[PATCH/RFC 00/11] Remove submodule from files-backend.c

[PATCH/RFC 00/11] Remove submodule from files-backend.c

[Nguyễn Thái Ngọc Duy]

This is on top of mh/submodule-hash, it:

 - centralizes path manipulation around submodule, $GIT_DIR... in
   files-backend.c to a new function files_path() with the intention
   to make it easier to change later. files_path() is destined to
   become

      strbuf_addbuf(&sb, refs->gitdir);
      strbuf_complete(&sb, '/');
      strbuf_vaddf(&sb, fmt, vap);

   but that can only be achieved once we get compound ref store.

 - removes git_path() and submodule_git_path() from files-backend.c. No
   more magic path translation as far as ref backend is concerned.

 - moves submodule path resolution code outside the backend.
   files-backend is now oblivious of submodules and in theory a
   submodule ref-store supports all operations (but I could be wrong,
   I didn't stare hard)

 - exposes get_submodule_ref_store() and get_main_ref_store() as public
   API. A new set of API around ref-store will be added. And
   get_worktree_ref_store() of course. The *_submodule() API might be
   removed, we'll see.

The problem with set_worktree_head_symref() (which peeks into another
gitdir) should be solved once we have get_worktree_ref_store(). That's
my next step.

Compound ref store will have to wait until I'm done with my
gc-in-worktree problem as I think I can live without it for now. I
think after compound ref store is in place, adding lmdb backend back
should be much cleaner because it does not care about either
submodules or worktrees.

Nguyễn Thái Ngọc Duy (11):
  refs-internal.c: make files_log_ref_write() static
  files-backend: convert git_path() to strbuf_git_path()
  files-backend: add files_path()
  files-backend: replace *git_path*() with files_path()
  refs.c: share is_per_worktree_ref() to files-backend.c
  refs-internal.h: correct is_per_worktree_ref()
  files-backend: remove the use of git_path()
  refs.c: factor submodule code out of get_ref_store()
  refs: move submodule code out of files-backend.c
  files-backend: remove submodule_allowed from files_downcast()
  refs: split and make get_*_ref_store() public API

 refs.c               | 125 ++++++++++++------
 refs.h               |  13 ++
 refs/files-backend.c | 350 ++++++++++++++++++++++++++++++---------------------
 refs/refs-internal.h |  28 ++---
 4 files changed, 316 insertions(+), 200 deletions(-)

-- 
2.11.0.157.gd943d85

[PATCH 01/11] refs-internal.c: make files_log_ref_write() static

[Nguyễn Thái Ngọc Duy]

Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
but probably never used outside refs-internal.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 3 +++
 refs/refs-internal.h | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index cdb6b8ff5..75565c3aa 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+			       const unsigned char *new_sha1, const char *msg,
+			       int flags, struct strbuf *err);
 
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 33adbf93b..59e65958a 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -222,10 +222,6 @@ struct ref_transaction {
 	enum ref_transaction_state state;
 };
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err);
-
 /*
  * Check for entries in extras that are within the specified
  * directory, where dirname is a reference directory name including
-- 
2.11.0.157.gd943d85

Re: [PATCH 01/11] refs-internal.c: make files_log_ref_write() static

[Ramsay Jones]

On 13/02/17 15:20, Nguyễn Thái Ngọc Duy wrote:
> Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
> but probably never used outside refs-internal.c
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 3 +++
>  refs/refs-internal.h | 4 ----
>  2 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index cdb6b8ff5..75565c3aa 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
>  					  const char *dirname, size_t len,
>  					  int incomplete);
>  static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
> +static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
> +			       const unsigned char *new_sha1, const char *msg,
> +			       int flags, struct strbuf *err);

Why? I don't like adding forward declarations unless it
is absolutely necessary (ie mutually recursive functions),
and even in the current 'pu' branch (@c04899d50), the
definition of this function appears before all uses in
this file. (ie, just add static to the definition).

What am I missing?

ATB,
Ramsay Jones

>  
>  static struct ref_dir *get_ref_dir(struct ref_entry *entry)
>  {
> diff --git a/refs/refs-internal.h b/refs/refs-internal.h
> index 33adbf93b..59e65958a 100644
> --- a/refs/refs-internal.h
> +++ b/refs/refs-internal.h
> @@ -222,10 +222,6 @@ struct ref_transaction {
>  	enum ref_transaction_state state;
>  };
>  
> -int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
> -			const unsigned char *new_sha1, const char *msg,
> -			int flags, struct strbuf *err);
> -
>  /*
>   * Check for entries in extras that are within the specified
>   * directory, where dirname is a reference directory name including
> 

Re: [PATCH 01/11] refs-internal.c: make files_log_ref_write() static

[Duy Nguyen]

On Tue, Feb 14, 2017 at 3:14 AM, Ramsay Jones
<ramsay@ramsayjones.plus.com> wrote:
>
>
> On 13/02/17 15:20, Nguyễn Thái Ngọc Duy wrote:
>> Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
>> but probably never used outside refs-internal.c
>>
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>>  refs/files-backend.c | 3 +++
>>  refs/refs-internal.h | 4 ----
>>  2 files changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/refs/files-backend.c b/refs/files-backend.c
>> index cdb6b8ff5..75565c3aa 100644
>> --- a/refs/files-backend.c
>> +++ b/refs/files-backend.c
>> @@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
>>                                         const char *dirname, size_t len,
>>                                         int incomplete);
>>  static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
>> +static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
>> +                            const unsigned char *new_sha1, const char *msg,
>> +                            int flags, struct strbuf *err);
>
> Why? I don't like adding forward declarations unless it
> is absolutely necessary (ie mutually recursive functions),
> and even in the current 'pu' branch (@c04899d50), the
> definition of this function appears before all uses in
> this file. (ie, just add static to the definition).
>
> What am I missing?

It may have been needed at one point. With all the code changes and
movements, I guess I forgot to remove it.
-- 
Duy

[PATCH 02/11] files-backend: convert git_path() to strbuf_git_path()

[Nguyễn Thái Ngọc Duy]

git_path() and friends are going to be killed in files-backend.c in near
future. And because there's a risk with overwriting buffer in
git_path(), let's convert them all to strbuf_git_path(). We'll have
easier time killing/converting strbuf_git_path() then because we won't
have to worry about memory management again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 114 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 90 insertions(+), 24 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 75565c3aa..6582c9b2d 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2169,6 +2169,8 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	static int timeout_configured = 0;
 	static int timeout_value = 1000;
 	struct packed_ref_cache *packed_ref_cache;
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
 
 	files_assert_main_repository(refs, "lock_packed_refs");
 
@@ -2177,10 +2179,13 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	if (hold_lock_file_for_update_timeout(
-			    &packlock, git_path("packed-refs"),
-			    flags, timeout_value) < 0)
+	strbuf_git_path(&sb, "packed-refs");
+	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
+						flags, timeout_value);
+	strbuf_release(&sb);
+	if (ret < 0)
 		return -1;
+
 	/*
 	 * Get the current packed-refs while holding the lock.  If the
 	 * packed-refs file has been modified since we last read it,
@@ -2335,6 +2340,9 @@ static void try_remove_empty_parents(char *name)
 	for (q = p; *q; q++)
 		;
 	while (1) {
+		struct strbuf sb = STRBUF_INIT;
+		int ret;
+
 		while (q > p && *q != '/')
 			q--;
 		while (q > p && *(q-1) == '/')
@@ -2342,7 +2350,10 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		if (rmdir(git_path("%s", name)))
+		strbuf_git_path(&sb, "%s", name);
+		ret = rmdir(sb.buf);
+		strbuf_release(&sb);
+		if (ret)
 			break;
 	}
 }
@@ -2431,7 +2442,11 @@ static int repack_without_refs(struct files_ref_store *refs,
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(refs, 0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "packed-refs");
+		unable_to_lock_message(sb.buf, errno, err);
+		strbuf_release(&sb);
 		return -1;
 	}
 	packed = get_packed_refs(refs);
@@ -2529,11 +2544,12 @@ static int rename_tmp_log(const char *newrefname)
 {
 	int attempts_remaining = 4;
 	struct strbuf path = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
 	int ret = -1;
 
- retry:
-	strbuf_reset(&path);
 	strbuf_git_path(&path, "logs/%s", newrefname);
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+ retry:
 	switch (safe_create_leading_directories_const(path.buf)) {
 	case SCLD_OK:
 		break; /* success */
@@ -2546,7 +2562,7 @@ static int rename_tmp_log(const char *newrefname)
 		goto out;
 	}
 
-	if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
+	if (rename(tmp_renamed_log.buf, path.buf)) {
 		if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
 			/*
 			 * rename(a, b) when b is an existing
@@ -2574,6 +2590,7 @@ static int rename_tmp_log(const char *newrefname)
 	ret = 0;
 out:
 	strbuf_release(&path);
+	strbuf_release(&tmp_renamed_log);
 	return ret;
 }
 
@@ -2614,9 +2631,15 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
-	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+	struct strbuf sb_oldref = STRBUF_INIT;
+	struct strbuf sb_newref = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
+	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	log = !lstat(sb_oldref.buf, &loginfo);
+	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2630,7 +2653,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
+	if (ret)
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
@@ -2709,13 +2737,19 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
+	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
+	strbuf_release(&sb_newref);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
 
 	return 1;
 }
@@ -3111,22 +3145,32 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
+	int ret;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_exists");
 
-	return !lstat(git_path("logs/%s", refname), &st) &&
-		S_ISREG(st.st_mode);
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "delete_reflog");
 
-	return remove_path(git_path("logs/%s", refname));
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = remove_path(sb.buf);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
@@ -3181,7 +3225,9 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3287,7 +3333,9 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3369,12 +3417,15 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 {
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
+	struct strbuf sb = STRBUF_INIT;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_iterator_begin");
 
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	iter->dir_iterator = dir_iterator_begin(git_path("logs"));
+	strbuf_git_path(&sb, "logs");
+	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	strbuf_release(&sb);
 	return ref_iterator;
 }
 
@@ -3843,8 +3894,13 @@ static int files_transaction_commit(struct ref_store *ref_store,
 		ret = TRANSACTION_GENERIC_ERROR;
 		goto cleanup;
 	}
-	for_each_string_list_item(ref_to_delete, &refs_to_delete)
-		unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
+	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		unlink_or_warn(sb.buf);
+		strbuf_release(&sb);
+	}
 	clear_loose_ref_cache(refs);
 
 cleanup:
@@ -4098,18 +4154,28 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct strbuf sb = STRBUF_INIT;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "init_db");
 
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	strbuf_git_path(&sb, "refs/heads");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
+	strbuf_git_path(&sb, "refs/tags");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		strbuf_git_path(&sb, "refs/heads");
+		adjust_shared_perm(sb.buf);
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "refs/tags");
+		adjust_shared_perm(sb.buf);
 	}
+	strbuf_release(&sb);
 	return 0;
 }
 
-- 
2.11.0.157.gd943d85

Re: [PATCH 02/11] files-backend: convert git_path() to strbuf_git_path()

[Ramsay Jones]

On 13/02/17 15:20, Nguyễn Thái Ngọc Duy wrote:
> git_path() and friends are going to be killed in files-backend.c in near
> future. And because there's a risk with overwriting buffer in
> git_path(), let's convert them all to strbuf_git_path(). We'll have
> easier time killing/converting strbuf_git_path() then because we won't
> have to worry about memory management again.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 114 ++++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 90 insertions(+), 24 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 75565c3aa..6582c9b2d 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -2169,6 +2169,8 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
>  	static int timeout_configured = 0;
>  	static int timeout_value = 1000;
>  	struct packed_ref_cache *packed_ref_cache;
> +	struct strbuf sb = STRBUF_INIT;
> +	int ret;
>  
>  	files_assert_main_repository(refs, "lock_packed_refs");
>  
> @@ -2177,10 +2179,13 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
>  		timeout_configured = 1;
>  	}
>  
> -	if (hold_lock_file_for_update_timeout(
> -			    &packlock, git_path("packed-refs"),
> -			    flags, timeout_value) < 0)
> +	strbuf_git_path(&sb, "packed-refs");
> +	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
> +						flags, timeout_value);
> +	strbuf_release(&sb);
> +	if (ret < 0)
>  		return -1;
> +
>  	/*
>  	 * Get the current packed-refs while holding the lock.  If the
>  	 * packed-refs file has been modified since we last read it,
> @@ -2335,6 +2340,9 @@ static void try_remove_empty_parents(char *name)
>  	for (q = p; *q; q++)
>  		;
>  	while (1) {
> +		struct strbuf sb = STRBUF_INIT;
> +		int ret;
> +
>  		while (q > p && *q != '/')
>  			q--;
>  		while (q > p && *(q-1) == '/')
> @@ -2342,7 +2350,10 @@ static void try_remove_empty_parents(char *name)
>  		if (q == p)
>  			break;
>  		*q = '\0';
> -		if (rmdir(git_path("%s", name)))
> +		strbuf_git_path(&sb, "%s", name);
> +		ret = rmdir(sb.buf);
> +		strbuf_release(&sb);
> +		if (ret)
>  			break;
>  	}
>  }
> @@ -2431,7 +2442,11 @@ static int repack_without_refs(struct files_ref_store *refs,
>  		return 0; /* no refname exists in packed refs */
>  
>  	if (lock_packed_refs(refs, 0)) {
> -		unable_to_lock_message(git_path("packed-refs"), errno, err);
> +		struct strbuf sb = STRBUF_INIT;
> +
> +		strbuf_git_path(&sb, "packed-refs");
> +		unable_to_lock_message(sb.buf, errno, err);
> +		strbuf_release(&sb);
>  		return -1;
>  	}
>  	packed = get_packed_refs(refs);
> @@ -2529,11 +2544,12 @@ static int rename_tmp_log(const char *newrefname)
>  {
>  	int attempts_remaining = 4;
>  	struct strbuf path = STRBUF_INIT;
> +	struct strbuf tmp_renamed_log = STRBUF_INIT;
>  	int ret = -1;
>  
> - retry:
> -	strbuf_reset(&path);
>  	strbuf_git_path(&path, "logs/%s", newrefname);
> +	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
> + retry:
>  	switch (safe_create_leading_directories_const(path.buf)) {
>  	case SCLD_OK:
>  		break; /* success */
> @@ -2546,7 +2562,7 @@ static int rename_tmp_log(const char *newrefname)
>  		goto out;
>  	}
>  
> -	if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
> +	if (rename(tmp_renamed_log.buf, path.buf)) {
>  		if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
>  			/*
>  			 * rename(a, b) when b is an existing
> @@ -2574,6 +2590,7 @@ static int rename_tmp_log(const char *newrefname)
>  	ret = 0;
>  out:
>  	strbuf_release(&path);
> +	strbuf_release(&tmp_renamed_log);
>  	return ret;
>  }
>  
> @@ -2614,9 +2631,15 @@ static int files_rename_ref(struct ref_store *ref_store,
>  	int flag = 0, logmoved = 0;
>  	struct ref_lock *lock;
>  	struct stat loginfo;
> -	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
> +	struct strbuf sb_oldref = STRBUF_INIT;
> +	struct strbuf sb_newref = STRBUF_INIT;
> +	struct strbuf tmp_renamed_log = STRBUF_INIT;
> +	int log, ret;
>  	struct strbuf err = STRBUF_INIT;
>  
> +	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> +	log = !lstat(sb_oldref.buf, &loginfo);
> +	strbuf_release(&sb_oldref);
>  	if (log && S_ISLNK(loginfo.st_mode))
>  		return error("reflog for %s is a symlink", oldrefname);
>  
> @@ -2630,7 +2653,12 @@ static int files_rename_ref(struct ref_store *ref_store,
>  	if (!rename_ref_available(oldrefname, newrefname))
>  		return 1;
>  
> -	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
> +	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> +	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
> +	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);

It probably won't make too much difference, but the two code
sequences above are not similar in terms of side-effects when
'log' is false. In that case, the two calls to git_path() and
the call to rename() are not made in the original code. In the
new sequence, the two calls to strbuf_git_path() are always made
(but rename() is not).

> +	strbuf_release(&sb_oldref);
> +	strbuf_release(&tmp_renamed_log);
> +	if (ret)
>  		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
>  			oldrefname, strerror(errno));
>  
> @@ -2709,13 +2737,19 @@ static int files_rename_ref(struct ref_store *ref_store,
>  	log_all_ref_updates = flag;
>  
>   rollbacklog:
> -	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
> +	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
> +	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> +	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))

ditto

>  		error("unable to restore logfile %s from %s: %s",
>  			oldrefname, newrefname, strerror(errno));
> +	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
>  	if (!logmoved && log &&
> -	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
> +	    rename(tmp_renamed_log.buf, sb_oldref.buf))

similar

>  		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
>  			oldrefname, strerror(errno));
> +	strbuf_release(&sb_newref);
> +	strbuf_release(&sb_oldref);
> +	strbuf_release(&tmp_renamed_log);
>  
>  	return 1;
>  }

ATB,
Ramsay Jones

[PATCH 03/11] files-backend: add files_path()

[Nguyễn Thái Ngọc Duy]

This will be the replacement for both git_path() and git_path_submodule()
in this file. The idea is backend takes a git path and use that,
oblivious of submodule, linked worktrees and such.

This is the middle step towards that. Eventually the "submodule" field
in 'struct files_ref_store' should be replace by "gitdir". And a
compound ref_store is created to combine two files backends together,
one represents the shared refs in $GIT_COMMON_DIR, one per-worktree. At
that point, files_path() becomes a wrapper of strbuf_vaddf().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6582c9b2d..39217a2ca 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -169,6 +169,9 @@ static int files_log_ref_write(const char *refname, const unsigned char *old_sha
 			       const unsigned char *new_sha1, const char *msg,
 			       int flags, struct strbuf *err);
 
+void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		const char *fmt, ...) __attribute__((format (printf, 3, 4)));
+
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
 	struct ref_dir *dir;
@@ -930,6 +933,23 @@ struct files_ref_store {
 /* Lock used for the main packed-refs file: */
 static struct lock_file packlock;
 
+void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		const char *fmt, ...)
+{
+	struct strbuf tmp = STRBUF_INIT;
+	va_list vap;
+
+	va_start(vap, fmt);
+	strbuf_vaddf(&tmp, fmt, vap);
+	va_end(vap);
+	if (refs->submodule)
+		strbuf_git_path_submodule(sb, refs->submodule,
+					  "%s", tmp.buf);
+	else
+		strbuf_git_path(sb, "%s", tmp.buf);
+	strbuf_release(&tmp);
+}
+
 /*
  * Increment the reference count of *packed_refs.
  */
-- 
2.11.0.157.gd943d85

Re: [PATCH 03/11] files-backend: add files_path()

[Ramsay Jones]

On 13/02/17 15:20, Nguyễn Thái Ngọc Duy wrote:
> This will be the replacement for both git_path() and git_path_submodule()
> in this file. The idea is backend takes a git path and use that,
> oblivious of submodule, linked worktrees and such.
> 
> This is the middle step towards that. Eventually the "submodule" field
> in 'struct files_ref_store' should be replace by "gitdir". And a
> compound ref_store is created to combine two files backends together,
> one represents the shared refs in $GIT_COMMON_DIR, one per-worktree. At
> that point, files_path() becomes a wrapper of strbuf_vaddf().
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 6582c9b2d..39217a2ca 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -169,6 +169,9 @@ static int files_log_ref_write(const char *refname, const unsigned char *old_sha
>  			       const unsigned char *new_sha1, const char *msg,
>  			       int flags, struct strbuf *err);
>  
> +void files_path(struct files_ref_store *refs, struct strbuf *sb,
> +		const char *fmt, ...) __attribute__((format (printf, 3, 4)));
> +

Why?

>  static struct ref_dir *get_ref_dir(struct ref_entry *entry)
>  {
>  	struct ref_dir *dir;
> @@ -930,6 +933,23 @@ struct files_ref_store {
>  /* Lock used for the main packed-refs file: */
>  static struct lock_file packlock;
>  
> +void files_path(struct files_ref_store *refs, struct strbuf *sb,
> +		const char *fmt, ...)
> +{
> +	struct strbuf tmp = STRBUF_INIT;
> +	va_list vap;
> +
> +	va_start(vap, fmt);
> +	strbuf_vaddf(&tmp, fmt, vap);
> +	va_end(vap);
> +	if (refs->submodule)
> +		strbuf_git_path_submodule(sb, refs->submodule,
> +					  "%s", tmp.buf);
> +	else
> +		strbuf_git_path(sb, "%s", tmp.buf);
> +	strbuf_release(&tmp);
> +}
> +
>  /*
>   * Increment the reference count of *packed_refs.
>   */
> 

ATB,
Ramsay Jones

[PATCH 04/11] files-backend: replace *git_path*() with files_path()

[Nguyễn Thái Ngọc Duy]

This centralizes all path rewriting of files-backend.c in one place so
we have easier time removing the path rewriting later. There could be
some hidden indirect git_path() though, I didn't audit the code to the
bottom.

Side note: set_worktree_head_symref() is a bad boy and should not be in
files-backend.c (probably should not exist in the first place). But
we'll leave it there until we have better multi-worktree support in refs
before we update it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 193 ++++++++++++++++++++++++++-------------------------
 1 file changed, 98 insertions(+), 95 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 39217a2ca..c69e4fe84 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,12 +165,13 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
-static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int files_log_ref_write(struct files_ref_store *refs,
+			       const char *refname, const unsigned char *old_sha1,
 			       const unsigned char *new_sha1, const char *msg,
 			       int flags, struct strbuf *err);
 
-void files_path(struct files_ref_store *refs, struct strbuf *sb,
-		const char *fmt, ...) __attribute__((format (printf, 3, 4)));
+static void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		       const char *fmt, ...) __attribute__((format (printf, 3, 4)));
 
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
@@ -933,8 +934,8 @@ struct files_ref_store {
 /* Lock used for the main packed-refs file: */
 static struct lock_file packlock;
 
-void files_path(struct files_ref_store *refs, struct strbuf *sb,
-		const char *fmt, ...)
+static void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		       const char *fmt, ...)
 {
 	struct strbuf tmp = STRBUF_INIT;
 	va_list vap;
@@ -1180,12 +1181,10 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
 {
 	char *packed_refs_file;
+	struct strbuf sb = STRBUF_INIT;
 
-	if (refs->submodule)
-		packed_refs_file = git_pathdup_submodule(refs->submodule,
-							 "packed-refs");
-	else
-		packed_refs_file = git_pathdup("packed-refs");
+	files_path(refs, &sb, "packed-refs");
+	packed_refs_file = strbuf_detach(&sb, NULL);
 
 	if (refs->packed &&
 	    !stat_validity_check(&refs->packed->validity, packed_refs_file))
@@ -1251,10 +1250,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 	size_t path_baselen;
 	int err = 0;
 
-	if (refs->submodule)
-		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
-	else
-		strbuf_git_path(&path, "%s", dirname);
+	files_path(refs, &path, "%s", dirname);
 	path_baselen = path.len;
 
 	if (err) {
@@ -1396,10 +1392,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	*type = 0;
 	strbuf_reset(&sb_path);
 
-	if (refs->submodule)
-		strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
-	else
-		strbuf_git_path(&sb_path, "%s", refname);
+	files_path(refs, &sb_path, "%s", refname);
 
 	path = sb_path.buf;
 
@@ -1587,7 +1580,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	*lock_p = lock = xcalloc(1, sizeof(*lock));
 
 	lock->ref_name = xstrdup(refname);
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 
 retry:
 	switch (safe_create_leading_directories(ref_file.buf)) {
@@ -2054,7 +2047,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	if (flags & REF_DELETING)
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
 					lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
@@ -2199,7 +2192,7 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	strbuf_git_path(&sb, "packed-refs");
+	files_path(refs, &sb, "packed-refs");
 	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
 						flags, timeout_value);
 	strbuf_release(&sb);
@@ -2345,7 +2338,7 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
  * Remove empty parents, but spare refs/ and immediate subdirs.
  * Note: munges *name.
  */
-static void try_remove_empty_parents(char *name)
+static void try_remove_empty_parents(struct files_ref_store *refs, char *name)
 {
 	char *p, *q;
 	int i;
@@ -2370,7 +2363,7 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		strbuf_git_path(&sb, "%s", name);
+		files_path(refs, &sb, "%s", name);
 		ret = rmdir(sb.buf);
 		strbuf_release(&sb);
 		if (ret)
@@ -2379,7 +2372,7 @@ static void try_remove_empty_parents(char *name)
 }
 
 /* make sure nobody touched the ref, and unlink */
-static void prune_ref(struct ref_to_prune *r)
+static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -2399,13 +2392,13 @@ static void prune_ref(struct ref_to_prune *r)
 	}
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
-	try_remove_empty_parents(r->name);
+	try_remove_empty_parents(refs, r->name);
 }
 
-static void prune_refs(struct ref_to_prune *r)
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	while (r) {
-		prune_ref(r);
+		prune_ref(refs, r);
 		r = r->next;
 	}
 }
@@ -2428,7 +2421,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 	if (commit_packed_refs(refs))
 		die_errno("unable to overwrite old ref-pack file");
 
-	prune_refs(cbdata.ref_to_prune);
+	prune_refs(refs, cbdata.ref_to_prune);
 	return 0;
 }
 
@@ -2464,7 +2457,7 @@ static int repack_without_refs(struct files_ref_store *refs,
 	if (lock_packed_refs(refs, 0)) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "packed-refs");
+		files_path(refs, &sb, "packed-refs");
 		unable_to_lock_message(sb.buf, errno, err);
 		strbuf_release(&sb);
 		return -1;
@@ -2560,15 +2553,15 @@ static int files_delete_refs(struct ref_store *ref_store,
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 {
 	int attempts_remaining = 4;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf tmp_renamed_log = STRBUF_INIT;
 	int ret = -1;
 
-	strbuf_git_path(&path, "logs/%s", newrefname);
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &path, "logs/%s", newrefname);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
  retry:
 	switch (safe_create_leading_directories_const(path.buf)) {
 	case SCLD_OK:
@@ -2657,7 +2650,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	log = !lstat(sb_oldref.buf, &loginfo);
 	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
@@ -2673,8 +2666,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
 	strbuf_release(&sb_oldref);
 	strbuf_release(&tmp_renamed_log);
@@ -2701,7 +2694,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			struct strbuf path = STRBUF_INIT;
 			int result;
 
-			strbuf_git_path(&path, "%s", newrefname);
+			files_path(refs, &path, "%s", newrefname);
 			result = remove_empty_directories(&path);
 			strbuf_release(&path);
 
@@ -2715,7 +2708,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 		}
 	}
 
-	if (log && rename_tmp_log(newrefname))
+	if (log && rename_tmp_log(refs, newrefname))
 		goto rollback;
 
 	logmoved = log;
@@ -2757,12 +2750,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_newref, "logs/%s", newrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
 	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
@@ -2818,11 +2811,13 @@ static int commit_ref(struct ref_lock *lock)
  * should_autocreate_reflog returns non-zero.  Otherwise, create it
  * regardless of the ref name.  Fill in *err and return -1 on failure.
  */
-static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
+static int log_ref_setup(struct files_ref_store *refs, const char *refname,
+			 struct strbuf *logfile, struct strbuf *err,
+			 int force_create)
 {
 	int logfd, oflags = O_APPEND | O_WRONLY;
 
-	strbuf_git_path(logfile, "logs/%s", refname);
+	files_path(refs, logfile, "logs/%s", refname);
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (safe_create_leading_directories(logfile->buf) < 0) {
 			strbuf_addf(err, "unable to create directory for '%s': "
@@ -2865,11 +2860,10 @@ static int files_create_reflog(struct ref_store *ref_store,
 {
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "create_reflog");
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "create_reflog");
-
-	ret = log_ref_setup(refname, &sb, err, force_create);
+	ret = log_ref_setup(refs, refname, &sb, err, force_create);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -2900,7 +2894,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
+static int log_ref_write_1(struct files_ref_store *refs,
+			   const char *refname, const unsigned char *old_sha1,
 			   const unsigned char *new_sha1, const char *msg,
 			   struct strbuf *logfile, int flags,
 			   struct strbuf *err)
@@ -2910,7 +2905,7 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
+	result = log_ref_setup(refs, refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
 
 	if (result)
 		return result;
@@ -2934,21 +2929,23 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int log_ref_write(struct files_ref_store *refs,
+			 const char *refname, const unsigned char *old_sha1,
 			 const unsigned char *new_sha1, const char *msg,
 			 int flags, struct strbuf *err)
 {
-	return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
-				   err);
+	return files_log_ref_write(refs, refname, old_sha1, new_sha1,
+				   msg, flags, err);
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+int files_log_ref_write(struct files_ref_store *refs,
+			const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)
 {
 	struct strbuf sb = STRBUF_INIT;
-	int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
-				  err);
+	int ret = log_ref_write_1(refs, refname, old_sha1, new_sha1, msg,
+				  &sb, flags, err);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -3005,7 +3002,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
+	if (log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
+			  sha1, logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
 			    lock->ref_name, old_msg);
@@ -3036,8 +3034,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
-					  logmsg, 0, &log_err)) {
+			if (log_ref_write(refs, "HEAD", lock->old_oid.hash,
+					  sha1, logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
 			}
@@ -3069,23 +3067,26 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 	return ret;
 }
 
-static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+static void update_symref_reflog(struct files_ref_store *refs,
+				 struct ref_lock *lock, const char *refname,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
 	if (logmsg && !read_ref(target, new_sha1) &&
-	    log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
+	    log_ref_write(refs, refname, lock->old_oid.hash,
+			  new_sha1, logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
 }
 
-static int create_symref_locked(struct ref_lock *lock, const char *refname,
+static int create_symref_locked(struct files_ref_store *refs,
+				struct ref_lock *lock, const char *refname,
 				const char *target, const char *logmsg)
 {
 	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(lock, refname, target, logmsg);
+		update_symref_reflog(refs, lock, refname, target, logmsg);
 		return 0;
 	}
 
@@ -3093,7 +3094,7 @@ static int create_symref_locked(struct ref_lock *lock, const char *refname,
 		return error("unable to fdopen %s: %s",
 			     lock->lk->tempfile.filename.buf, strerror(errno));
 
-	update_symref_reflog(lock, refname, target, logmsg);
+	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
 	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
@@ -3122,13 +3123,19 @@ static int files_create_symref(struct ref_store *ref_store,
 		return -1;
 	}
 
-	ret = create_symref_locked(lock, refname, target, logmsg);
+	ret = create_symref_locked(refs, lock, refname, target, logmsg);
 	unlock_ref(lock);
 	return ret;
 }
 
 int set_worktree_head_symref(const char *gitdir, const char *target)
 {
+	/*
+	 * FIXME: this obviously will not work well for future refs
+	 * backends. This function needs to die.
+	 */
+	struct files_ref_store *refs =
+		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3155,7 +3162,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	lock->lk = &head_lock;
 	lock->ref_name = xstrdup(head_rel);
 
-	ret = create_symref_locked(lock, head_rel, target, NULL);
+	ret = create_symref_locked(refs, lock, head_rel, target, NULL);
 
 	unlock_ref(lock); /* will free lock */
 	strbuf_release(&head_path);
@@ -3165,14 +3172,13 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_exists");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
 	strbuf_release(&sb);
 	return ret;
@@ -3181,13 +3187,12 @@ static int files_reflog_exists(struct ref_store *ref_store,
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "delete_reflog");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = remove_path(sb.buf);
 	strbuf_release(&sb);
 	return ret;
@@ -3237,15 +3242,14 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     each_reflog_ent_fn fn,
 					     void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
 	int ret = 0, at_tail = 1;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3346,14 +3350,13 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     const char *refname,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3435,15 +3438,14 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_iterator_begin");
-
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	strbuf_git_path(&sb, "logs");
+	files_path(refs, &sb, "logs");
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
 	strbuf_release(&sb);
 	return ref_iterator;
@@ -3867,8 +3869,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (log_ref_write(lock->ref_name, lock->old_oid.hash,
-					  update->new_sha1,
+			if (log_ref_write(refs, lock->ref_name,
+					  lock->old_oid.hash, update->new_sha1,
 					  update->msg, update->flags, err)) {
 				char *old_msg = strbuf_detach(err, NULL);
 
@@ -3917,7 +3919,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		files_path(refs, &sb, "logs/%s", ref_to_delete->string);
 		unlink_or_warn(sb.buf);
 		strbuf_release(&sb);
 	}
@@ -4079,6 +4081,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	int status = 0;
 	int type;
 	struct strbuf err = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 
 	memset(&cb, 0, sizeof(cb));
 	cb.flags = flags;
@@ -4103,7 +4106,8 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		return 0;
 	}
 
-	log_file = git_pathdup("logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
+	log_file = strbuf_detach(&sb, NULL);
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 		/*
 		 * Even though holding $GIT_DIR/logs/$reflog.lock has
@@ -4174,25 +4178,24 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "init_db");
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	strbuf_git_path(&sb, "refs/heads");
+	files_path(refs, &sb, "refs/heads");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
-	strbuf_git_path(&sb, "refs/tags");
+	files_path(refs, &sb, "refs/tags");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		strbuf_git_path(&sb, "refs/heads");
+		files_path(refs, &sb, "refs/heads");
 		adjust_shared_perm(sb.buf);
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "refs/tags");
+		files_path(refs, &sb, "refs/tags");
 		adjust_shared_perm(sb.buf);
 	}
 	strbuf_release(&sb);
-- 
2.11.0.157.gd943d85

Re: [PATCH 04/11] files-backend: replace *git_path*() with files_path()

[Ramsay Jones]

On 13/02/17 15:20, Nguyễn Thái Ngọc Duy wrote:
> This centralizes all path rewriting of files-backend.c in one place so
> we have easier time removing the path rewriting later. There could be
> some hidden indirect git_path() though, I didn't audit the code to the
> bottom.
> 
> Side note: set_worktree_head_symref() is a bad boy and should not be in
> files-backend.c (probably should not exist in the first place). But
> we'll leave it there until we have better multi-worktree support in refs
> before we update it.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 193 ++++++++++++++++++++++++++-------------------------
>  1 file changed, 98 insertions(+), 95 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 39217a2ca..c69e4fe84 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -165,12 +165,13 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
>  					  const char *dirname, size_t len,
>  					  int incomplete);
>  static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
> -static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
> +static int files_log_ref_write(struct files_ref_store *refs,
> +			       const char *refname, const unsigned char *old_sha1,
>  			       const unsigned char *new_sha1, const char *msg,
>  			       int flags, struct strbuf *err);
>  
> -void files_path(struct files_ref_store *refs, struct strbuf *sb,
> -		const char *fmt, ...) __attribute__((format (printf, 3, 4)));

You only added this in the last commit, so maybe mark it static in
the previous patch! Also, just in case you were wondering, the 'Why?'
of the previous email was, "Why do you need this forward declaration?"
(hint: you don't ;-)

> +static void files_path(struct files_ref_store *refs, struct strbuf *sb,
> +		       const char *fmt, ...) __attribute__((format (printf, 3, 4)));
>  
>  static struct ref_dir *get_ref_dir(struct ref_entry *entry)
>  {
> @@ -933,8 +934,8 @@ struct files_ref_store {
>  /* Lock used for the main packed-refs file: */
>  static struct lock_file packlock;
>  
> -void files_path(struct files_ref_store *refs, struct strbuf *sb,
> -		const char *fmt, ...)
> +static void files_path(struct files_ref_store *refs, struct strbuf *sb,
> +		       const char *fmt, ...)
>  {
>  	struct strbuf tmp = STRBUF_INIT;
>  	va_list vap;

ATB,
Ramsay Jones

Re: [PATCH 04/11] files-backend: replace *git_path*() with files_path()

[Duy Nguyen]

On Tue, Feb 14, 2017 at 3:58 AM, Ramsay Jones
<ramsay@ramsayjones.plus.com> wrote:
>> -void files_path(struct files_ref_store *refs, struct strbuf *sb,
>> -             const char *fmt, ...) __attribute__((format (printf, 3, 4)));
>
> You only added this in the last commit, so maybe mark it static in
> the previous patch! Also, just in case you were wondering, the 'Why?'
> of the previous email was, "Why do you need this forward declaration?"
> (hint: you don't ;-)

Yeah, my compiler considers unused static functions an error. But I
guess I should adjust those million compiler flags instead of doing it
like this. I'll need to check if it's an error with DEVELOPER_CFLAGS
because people may bisect with that.
-- 
Duy

[PATCH 05/11] refs.c: share is_per_worktree_ref() to files-backend.c

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 6 ------
 refs/refs-internal.h | 6 ++++++
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/refs.c b/refs.c
index f03dcf58b..2cacd934e 100644
--- a/refs.c
+++ b/refs.c
@@ -489,12 +489,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-static int is_per_worktree_ref(const char *refname)
-{
-	return !strcmp(refname, "HEAD") ||
-		starts_with(refname, "refs/bisect/");
-}
-
 static int is_pseudoref_syntax(const char *refname)
 {
 	const char *c;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 59e65958a..f4aed49f5 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -651,4 +651,10 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 				    int resolve_flags,
 				    unsigned char *sha1, int *flags);
 
+static inline int is_per_worktree_ref(const char *refname)
+{
+	return !strcmp(refname, "HEAD") ||
+		starts_with(refname, "refs/bisect/");
+}
+
 #endif /* REFS_REFS_INTERNAL_H */
-- 
2.11.0.157.gd943d85

[PATCH 06/11] refs-internal.h: correct is_per_worktree_ref()

[Nguyễn Thái Ngọc Duy]

All refs outside refs/ directory is per-worktree, not just HEAD.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/refs-internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index f4aed49f5..69d02b6ba 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -653,7 +653,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 
 static inline int is_per_worktree_ref(const char *refname)
 {
-	return !strcmp(refname, "HEAD") ||
+	return !starts_with(refname, "refs/") ||
 		starts_with(refname, "refs/bisect/");
 }
 
-- 
2.11.0.157.gd943d85

Re: [PATCH 06/11] refs-internal.h: correct is_per_worktree_ref()

[Stefan Beller]

On Mon, Feb 13, 2017 at 7:20 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> All refs outside refs/ directory is per-worktree, not just HEAD.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/refs-internal.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/refs/refs-internal.h b/refs/refs-internal.h
> index f4aed49f5..69d02b6ba 100644
> --- a/refs/refs-internal.h
> +++ b/refs/refs-internal.h
> @@ -653,7 +653,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
>
>  static inline int is_per_worktree_ref(const char *refname)
>  {
> -       return !strcmp(refname, "HEAD") ||
> +       return !starts_with(refname, "refs/") ||
>                 starts_with(refname, "refs/bisect/");

you're loosing HEAD here? (assuming we get HEAD in
short form here, as well as long form refs/HEAD)

>  }
>
> --
> 2.11.0.157.gd943d85
>

Re: [PATCH 06/11] refs-internal.h: correct is_per_worktree_ref()

[Duy Nguyen]

On Tue, Feb 14, 2017 at 5:37 AM, Stefan Beller <sbeller@google.com> wrote:
> On Mon, Feb 13, 2017 at 7:20 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
>> All refs outside refs/ directory is per-worktree, not just HEAD.
>>
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>>  refs/refs-internal.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/refs/refs-internal.h b/refs/refs-internal.h
>> index f4aed49f5..69d02b6ba 100644
>> --- a/refs/refs-internal.h
>> +++ b/refs/refs-internal.h
>> @@ -653,7 +653,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
>>
>>  static inline int is_per_worktree_ref(const char *refname)
>>  {
>> -       return !strcmp(refname, "HEAD") ||
>> +       return !starts_with(refname, "refs/") ||
>>                 starts_with(refname, "refs/bisect/");
>
> you're loosing HEAD here? (assuming we get HEAD in
> short form here, as well as long form refs/HEAD)

I don't understand. if refname is HEAD then both !strcmp(...) and
!starts_with(refname, "refs/") return 1. If it's refs/HEAD, both
return 0. In other words, there's no functional changes?
-- 
Duy

Re: [PATCH 06/11] refs-internal.h: correct is_per_worktree_ref()

[Stefan Beller]

On Tue, Feb 14, 2017 at 1:40 AM, Duy Nguyen <pclouds@gmail.com> wrote:
> On Tue, Feb 14, 2017 at 5:37 AM, Stefan Beller <sbeller@google.com> wrote:
>> On Mon, Feb 13, 2017 at 7:20 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
>>> All refs outside refs/ directory is per-worktree, not just HEAD.
>>>
>>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>>> ---
>>>  refs/refs-internal.h | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/refs/refs-internal.h b/refs/refs-internal.h
>>> index f4aed49f5..69d02b6ba 100644
>>> --- a/refs/refs-internal.h
>>> +++ b/refs/refs-internal.h
>>> @@ -653,7 +653,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
>>>
>>>  static inline int is_per_worktree_ref(const char *refname)
>>>  {
>>> -       return !strcmp(refname, "HEAD") ||
>>> +       return !starts_with(refname, "refs/") ||
>>>                 starts_with(refname, "refs/bisect/");
>>
>> you're loosing HEAD here? (assuming we get HEAD in
>> short form here, as well as long form refs/HEAD)
>
> I don't understand. if refname is HEAD then both !strcmp(...) and
> !starts_with(refname, "refs/") return 1. If it's refs/HEAD, both
> return 0. In other words, there's no functional changes?

eh, my bad. You're right.

[PATCH 07/11] files-backend: remove the use of git_path()

[Nguyễn Thái Ngọc Duy]

Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
deciding what goes where. The end goal is to pass $GIT_DIR only. A
refs "view" of a linked worktree is a logical ref store that combines
two files backends together.

(*) Not entirely true since strbuf_git_path_submodule() still does path
translation underneath. But that's for another patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index c69e4fe84..50eb9edb6 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -927,6 +927,9 @@ struct files_ref_store {
 	 */
 	const char *submodule;
 
+	struct strbuf gitdir;
+	struct strbuf gitcommondir;
+
 	struct ref_entry *loose;
 	struct packed_ref_cache *packed;
 };
@@ -939,6 +942,7 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 {
 	struct strbuf tmp = STRBUF_INIT;
 	va_list vap;
+	const char *ref;
 
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
@@ -946,8 +950,12 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	if (refs->submodule)
 		strbuf_git_path_submodule(sb, refs->submodule,
 					  "%s", tmp.buf);
+	else if (is_per_worktree_ref(tmp.buf) ||
+		 (skip_prefix(tmp.buf, "logs/", &ref) &&
+		  is_per_worktree_ref(ref)))
+		strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
 	else
-		strbuf_git_path(sb, "%s", tmp.buf);
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
 	strbuf_release(&tmp);
 }
 
@@ -1006,7 +1014,15 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
-	refs->submodule = xstrdup_or_null(submodule);
+	strbuf_init(&refs->gitdir, 0);
+	strbuf_init(&refs->gitcommondir, 0);
+
+	if (submodule) {
+		refs->submodule = xstrdup_or_null(submodule);
+	} else {
+		strbuf_addstr(&refs->gitdir, get_git_dir());
+		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
+	}
 
 	return ref_store;
 }
-- 
2.11.0.157.gd943d85

Re: [PATCH 07/11] files-backend: remove the use of git_path()

[Stefan Beller]

> +
> +       if (submodule) {
> +               refs->submodule = xstrdup_or_null(submodule);

drop the _or_null here?

So in this patch we have either
* submodule set
* or gitdir/gitcommondir set

which means that we exercise the commondir for regular repos.
In the future when we want to be able to have a combination of worktrees
and submodules this ought to be possible by setting submodule != NULL
and still populating the gitdir/commondir buffers.

Thanks,
Stefan

Re: [PATCH 07/11] files-backend: remove the use of git_path()

[Duy Nguyen]

On Tue, Feb 14, 2017 at 6:09 AM, Stefan Beller <sbeller@google.com> wrote:
>> +
>> +       if (submodule) {
>> +               refs->submodule = xstrdup_or_null(submodule);
>
> drop the _or_null here?
>
> So in this patch we have either
> * submodule set
> * or gitdir/gitcommondir set
>
> which means that we exercise the commondir for regular repos.
> In the future when we want to be able to have a combination of worktrees
> and submodules this ought to be possible by setting submodule != NULL
> and still populating the gitdir/commondir buffers.

You probably have seen it by now. In the near future, submodule is
completely gone from here. We convert to a .git dir before we pass in
here. In a farther future, gitcommondir will be gone too with all the
per-worktree logic in this file. A linked worktree consists of two
backends actually, one per-worktree (which remains files-based), the
other for shared refs, which could be files, lmdb or whatever.
Stacking up submodule on top of a linked worktree should not be a
problem.
-- 
Duy

[PATCH 08/11] refs.c: factor submodule code out of get_ref_store()

[Nguyễn Thái Ngọc Duy]

This code is going to be expanded a bit soon. Keep it out for
better readability later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/refs.c b/refs.c
index 2cacd934e..8ef7a52ba 100644
--- a/refs.c
+++ b/refs.c
@@ -1445,6 +1445,18 @@ static struct ref_store *lookup_ref_store(const char *submodule)
 	return entry ? entry->refs : NULL;
 }
 
+static struct ref_store *init_submodule_ref_store(const char *submodule)
+{
+	struct strbuf submodule_sb = STRBUF_INIT;
+	struct ref_store *refs = NULL;
+
+	strbuf_addstr(&submodule_sb, submodule);
+	if (is_nonbare_repository_dir(&submodule_sb))
+		refs = ref_store_init(submodule);
+	strbuf_release(&submodule_sb);
+	return refs;
+}
+
 struct ref_store *get_ref_store(const char *submodule)
 {
 	struct ref_store *refs;
@@ -1457,14 +1469,8 @@ struct ref_store *get_ref_store(const char *submodule)
 	} else {
 		refs = lookup_ref_store(submodule);
 
-		if (!refs) {
-			struct strbuf submodule_sb = STRBUF_INIT;
-
-			strbuf_addstr(&submodule_sb, submodule);
-			if (is_nonbare_repository_dir(&submodule_sb))
-				refs = ref_store_init(submodule);
-			strbuf_release(&submodule_sb);
-		}
+		if (!refs)
+			refs = init_submodule_ref_store(submodule);
 	}
 
 	return refs;
-- 
2.11.0.157.gd943d85

Re: [PATCH 08/11] refs.c: factor submodule code out of get_ref_store()

[Stefan Beller]

On Mon, Feb 13, 2017 at 7:20 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> This code is going to be expanded a bit soon. Keep it out for
> better readability later.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---

Looks good,
Thanks,
Stefan

[PATCH 09/11] refs: move submodule code out of files-backend.c

[Nguyễn Thái Ngọc Duy]

files-backend is now initialized with a $GIT_DIR. Converting a submodule
path to where real submodule gitdir is located is done in get_ref_store().

The new code in init_submodule_ref_store() is basically a copy of
strbuf_git_path_submodule().

This gives a slight performance improvement for submodules since we
don't convert submodule path to gitdir at every backend call like
before. We pay that once at ref-store creation.

More cleanup in files_downcast() follows shortly. It's separate to keep
noises from this patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 48 +++++++++++++++++++++++++++++++++++++++++-------
 refs/files-backend.c | 25 +++++++------------------
 refs/refs-internal.h |  6 +++---
 3 files changed, 51 insertions(+), 28 deletions(-)

diff --git a/refs.c b/refs.c
index 8ef7a52ba..9ac194945 100644
--- a/refs.c
+++ b/refs.c
@@ -9,6 +9,7 @@
 #include "refs/refs-internal.h"
 #include "object.h"
 #include "tag.h"
+#include "submodule-config.h"
 
 /*
  * List of all available backends
@@ -1410,7 +1411,7 @@ static void register_ref_store(struct ref_store *refs, const char *submodule)
  * Create, record, and return a ref_store instance for the specified
  * submodule (or the main repository if submodule is NULL).
  */
-static struct ref_store *ref_store_init(const char *submodule)
+static struct ref_store *ref_store_init(const char *submodule, const char *gitdir)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1419,7 +1420,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(submodule);
+	refs = be->init(gitdir);
 	register_ref_store(refs, submodule);
 	return refs;
 }
@@ -1445,15 +1446,48 @@ static struct ref_store *lookup_ref_store(const char *submodule)
 	return entry ? entry->refs : NULL;
 }
 
-static struct ref_store *init_submodule_ref_store(const char *submodule)
+static struct ref_store *init_submodule_ref_store(const char *path)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
+	struct strbuf git_submodule_common_dir = STRBUF_INIT;
+	struct strbuf git_submodule_dir = STRBUF_INIT;
+	struct strbuf buf = STRBUF_INIT;
+	const char *git_dir;
+	const struct submodule *sub;
 	struct ref_store *refs = NULL;
 
-	strbuf_addstr(&submodule_sb, submodule);
-	if (is_nonbare_repository_dir(&submodule_sb))
-		refs = ref_store_init(submodule);
+	strbuf_addstr(&submodule_sb, path);
+	if (!is_nonbare_repository_dir(&submodule_sb))
+		goto done;
+
+	strbuf_addstr(&buf, path);
+	strbuf_complete(&buf, '/');
+	strbuf_addstr(&buf, ".git");
+
+	git_dir = read_gitfile(buf.buf);
+	if (git_dir) {
+		strbuf_reset(&buf);
+		strbuf_addstr(&buf, git_dir);
+	}
+	if (!is_git_directory(buf.buf)) {
+		gitmodules_config();
+		sub = submodule_from_path(null_sha1, path);
+		if (!sub)
+			goto done;
+		strbuf_reset(&buf);
+		strbuf_git_path(&buf, "%s/%s", "modules", sub->name);
+	}
+	strbuf_addch(&buf, '/');
+	strbuf_addbuf(&git_submodule_dir, &buf);
+
+	refs = ref_store_init(path, git_submodule_dir.buf);
+
+done:
+	strbuf_release(&git_submodule_dir);
+	strbuf_release(&git_submodule_common_dir);
 	strbuf_release(&submodule_sb);
+	strbuf_release(&buf);
+
 	return refs;
 }
 
@@ -1465,7 +1499,7 @@ struct ref_store *get_ref_store(const char *submodule)
 		refs = lookup_ref_store(NULL);
 
 		if (!refs)
-			refs = ref_store_init(NULL);
+			refs = ref_store_init(NULL, NULL);
 	} else {
 		refs = lookup_ref_store(submodule);
 
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 50eb9edb6..834bc6fdf 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -920,13 +920,6 @@ struct packed_ref_cache {
 struct files_ref_store {
 	struct ref_store base;
 
-	/*
-	 * The name of the submodule represented by this object, or
-	 * NULL if it represents the main repository's reference
-	 * store:
-	 */
-	const char *submodule;
-
 	struct strbuf gitdir;
 	struct strbuf gitcommondir;
 
@@ -947,12 +940,9 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
 	va_end(vap);
-	if (refs->submodule)
-		strbuf_git_path_submodule(sb, refs->submodule,
-					  "%s", tmp.buf);
-	else if (is_per_worktree_ref(tmp.buf) ||
-		 (skip_prefix(tmp.buf, "logs/", &ref) &&
-		  is_per_worktree_ref(ref)))
+	if (is_per_worktree_ref(tmp.buf) ||
+	    (skip_prefix(tmp.buf, "logs/", &ref) &&
+	     is_per_worktree_ref(ref)))
 		strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
 	else
 		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
@@ -1007,7 +997,7 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *submodule)
+static struct ref_store *files_ref_store_create(const char *gitdir)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
@@ -1017,8 +1007,9 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 	strbuf_init(&refs->gitdir, 0);
 	strbuf_init(&refs->gitcommondir, 0);
 
-	if (submodule) {
-		refs->submodule = xstrdup_or_null(submodule);
+	if (gitdir) {
+		strbuf_addstr(&refs->gitdir, gitdir);
+		get_common_dir_noenv(&refs->gitcommondir, gitdir);
 	} else {
 		strbuf_addstr(&refs->gitdir, get_git_dir());
 		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
@@ -1034,8 +1025,6 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	if (refs->submodule)
-		die("BUG: %s called for a submodule", caller);
 }
 
 /*
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 69d02b6ba..d7112770d 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -476,12 +476,12 @@ struct ref_store;
 /* refs backends */
 
 /*
- * Initialize the ref_store for the specified submodule, or for the
- * main repository if submodule == NULL. These functions should call
+ * Initialize the ref_store for the specified gitdir, or for the
+ * current repository if gitdir == NULL. These functions should call
  * base_ref_store_init() to initialize the shared part of the
  * ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *submodule);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
-- 
2.11.0.157.gd943d85

Re: [PATCH 09/11] refs: move submodule code out of files-backend.c

[Stefan Beller]

On Mon, Feb 13, 2017 at 7:20 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> files-backend is now initialized with a $GIT_DIR. Converting a submodule
> path to where real submodule gitdir is located is done in get_ref_store().
>
> The new code in init_submodule_ref_store() is basically a copy of
> strbuf_git_path_submodule().
>
> This gives a slight performance improvement for submodules since we
> don't convert submodule path to gitdir at every backend call like
> before. We pay that once at ref-store creation.
>
> More cleanup in files_downcast() follows shortly. It's separate to keep
> noises from this patch.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.c               | 48 +++++++++++++++++++++++++++++++++++++++++-------
>  refs/files-backend.c | 25 +++++++------------------
>  refs/refs-internal.h |  6 +++---
>  3 files changed, 51 insertions(+), 28 deletions(-)
>
> diff --git a/refs.c b/refs.c
> index 8ef7a52ba..9ac194945 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -9,6 +9,7 @@
>  #include "refs/refs-internal.h"
>  #include "object.h"
>  #include "tag.h"
> +#include "submodule-config.h"
>
>  /*
>   * List of all available backends
> @@ -1410,7 +1411,7 @@ static void register_ref_store(struct ref_store *refs, const char *submodule)
>   * Create, record, and return a ref_store instance for the specified
>   * submodule (or the main repository if submodule is NULL).
>   */
> -static struct ref_store *ref_store_init(const char *submodule)
> +static struct ref_store *ref_store_init(const char *submodule, const char *gitdir)
>  {
>         const char *be_name = "files";
>         struct ref_storage_be *be = find_ref_storage_backend(be_name);
> @@ -1419,7 +1420,7 @@ static struct ref_store *ref_store_init(const char *submodule)
>         if (!be)
>                 die("BUG: reference backend %s is unknown", be_name);
>
> -       refs = be->init(submodule);
> +       refs = be->init(gitdir);
>         register_ref_store(refs, submodule);
>         return refs;
>  }
> @@ -1445,15 +1446,48 @@ static struct ref_store *lookup_ref_store(const char *submodule)
>         return entry ? entry->refs : NULL;
>  }
>
> -static struct ref_store *init_submodule_ref_store(const char *submodule)
> +static struct ref_store *init_submodule_ref_store(const char *path)
>  {
>         struct strbuf submodule_sb = STRBUF_INIT;
> +       struct strbuf git_submodule_common_dir = STRBUF_INIT;
> +       struct strbuf git_submodule_dir = STRBUF_INIT;
> +       struct strbuf buf = STRBUF_INIT;
> +       const char *git_dir;
> +       const struct submodule *sub;
>         struct ref_store *refs = NULL;
>
> -       strbuf_addstr(&submodule_sb, submodule);
> -       if (is_nonbare_repository_dir(&submodule_sb))
> -               refs = ref_store_init(submodule);
> +       strbuf_addstr(&submodule_sb, path);
> +       if (!is_nonbare_repository_dir(&submodule_sb))
> +               goto done;
> +
> +       strbuf_addstr(&buf, path);
> +       strbuf_complete(&buf, '/');
> +       strbuf_addstr(&buf, ".git");
> +
> +       git_dir = read_gitfile(buf.buf);

if buf.buf is a (git) directory as opposed to a git file,
we error out in read_gitfile. Did you mean to use
read_gitfile_gently here or rather even resolve_gitdir_gently ?

> +       if (git_dir) {

when not using the _gently version git_dir is always
non NULL here (or we're dead)?

> +               strbuf_reset(&buf);
> +               strbuf_addstr(&buf, git_dir);
> +       }
> +       if (!is_git_directory(buf.buf)) {
> +               gitmodules_config();
> +               sub = submodule_from_path(null_sha1, path);
> +               if (!sub)
> +                       goto done;
> +               strbuf_reset(&buf);
> +               strbuf_git_path(&buf, "%s/%s", "modules", sub->name);

You can inline "modules" into the format string?

> +       }
> +       strbuf_addch(&buf, '/');
> +       strbuf_addbuf(&git_submodule_dir, &buf);
> +
> +       refs = ref_store_init(path, git_submodule_dir.buf);

strbuf_detach (git_submodule_dir) here, such that we keep
the string alive despite the release of the strbuf below?

so essentially this function
* takes a submodule path
* checks if there is a repo at the given path in the working tree
* resolves the gitfile if any
* if the gitfile could not resolve to a valid repo just make up the
  location to be $GIT_DIR/modules/<name>

sounds confusing to me. I need to reread it later.

>
> -       if (submodule) {
> -               refs->submodule = xstrdup_or_null(submodule);
> +       if (gitdir) {
> +               strbuf_addstr(&refs->gitdir, gitdir);
> +               get_common_dir_noenv(&refs->gitcommondir, gitdir);

Oh I see. we loose the _or_null here, so my remark on the previous patch
might be just unneeded work.

>         } else {
>                 strbuf_addstr(&refs->gitdir, get_git_dir());
>                 strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
> @@ -1034,8 +1025,6 @@ static struct ref_store *files_ref_store_create(const char *submodule)
>  static void files_assert_main_repository(struct files_ref_store *refs,
>                                          const char *caller)
>  {
> -       if (refs->submodule)
> -               die("BUG: %s called for a submodule", caller);
>  }

In a followup we'd get rid of files_assert_main_repository
presumably?

Thanks,
Stefan

Re: [PATCH 09/11] refs: move submodule code out of files-backend.c

[Duy Nguyen]

On Tue, Feb 14, 2017 at 6:35 AM, Stefan Beller <sbeller@google.com> wrote:
>> +       git_dir = read_gitfile(buf.buf);
>
> if buf.buf is a (git) directory as opposed to a git file,
> we error out in read_gitfile. Did you mean to use
> read_gitfile_gently here or rather even resolve_gitdir_gently ?

This is what strbuf_git_path_submodule() does. I don't know the
backstory so I'm going to keep it as it is to keep the behavior
exactly (or very close) as before. We can replace it with a better
version (with explanation and all).

>> +       if (git_dir) {
>
> when not using the _gently version git_dir is always
> non NULL here (or we're dead)?
>
>> +               strbuf_reset(&buf);
>> +               strbuf_addstr(&buf, git_dir);
>> +       }
>> +       if (!is_git_directory(buf.buf)) {
>> +               gitmodules_config();
>> +               sub = submodule_from_path(null_sha1, path);
>> +               if (!sub)
>> +                       goto done;
>> +               strbuf_reset(&buf);
>> +               strbuf_git_path(&buf, "%s/%s", "modules", sub->name);
>
> You can inline "modules" into the format string?

Hm.. because this is strbuf_git_path_submodule() code. Perhaps it's
better to split it to a separate function and call it from here? Then
you can make more improvements on top that benefit everybody.

>>         } else {
>>                 strbuf_addstr(&refs->gitdir, get_git_dir());
>>                 strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
>> @@ -1034,8 +1025,6 @@ static struct ref_store *files_ref_store_create(const char *submodule)
>>  static void files_assert_main_repository(struct files_ref_store *refs,
>>                                          const char *caller)
>>  {
>> -       if (refs->submodule)
>> -               die("BUG: %s called for a submodule", caller);
>>  }
>
> In a followup we'd get rid of files_assert_main_repository
> presumably?

Yes. Can't delete it now because I would need to touch all callers.
-- 
Duy

[PATCH 10/11] files-backend: remove submodule_allowed from files_downcast()

[Nguyễn Thái Ngọc Duy]

Since submodule or not is irrelevant to files-backend after the last
patch, remove the parameter from files_downcast() and kill
files_assert_main_repository().

PS. This implies that all ref operations are allowed for submodules. But
we may need to look more closely to see if that's really true...

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 69 ++++++++++++++++------------------------------------
 1 file changed, 21 insertions(+), 48 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 834bc6fdf..2fb270b6f 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1019,23 +1019,13 @@ static struct ref_store *files_ref_store_create(const char *gitdir)
 }
 
 /*
- * Die if refs is for a submodule (i.e., not for the main repository).
- * caller is used in any necessary error messages.
- */
-static void files_assert_main_repository(struct files_ref_store *refs,
-					 const char *caller)
-{
-}
-
-/*
  * Downcast ref_store to files_ref_store. Die if ref_store is not a
  * files_ref_store. If submodule_allowed is not true, then also die if
  * files_ref_store is for a submodule (i.e., not for the main
  * repository). caller is used in any necessary error messages.
  */
-static struct files_ref_store *files_downcast(
-		struct ref_store *ref_store, int submodule_allowed,
-		const char *caller)
+static struct files_ref_store *files_downcast(struct ref_store *ref_store,
+					      const char *caller)
 {
 	struct files_ref_store *refs;
 
@@ -1045,9 +1035,6 @@ static struct files_ref_store *files_downcast(
 
 	refs = (struct files_ref_store *)ref_store;
 
-	if (!submodule_allowed)
-		files_assert_main_repository(refs, caller);
-
 	return refs;
 }
 
@@ -1383,7 +1370,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "read_raw_ref");
+		files_downcast(ref_store, "read_raw_ref");
 	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
@@ -1576,7 +1563,6 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	int ret = TRANSACTION_GENERIC_ERROR;
 
 	assert(err);
-	files_assert_main_repository(refs, "lock_raw_ref");
 
 	*type = 0;
 
@@ -1800,7 +1786,7 @@ static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
 static int files_peel_ref(struct ref_store *ref_store,
 			  const char *refname, unsigned char *sha1)
 {
-	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
+	struct files_ref_store *refs = files_downcast(ref_store, "peel_ref");
 	int flag;
 	unsigned char base[20];
 
@@ -1909,7 +1895,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 		const char *prefix, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "ref_iterator_begin");
+		files_downcast(ref_store, "ref_iterator_begin");
 	struct ref_dir *loose_dir, *packed_dir;
 	struct ref_iterator *loose_iter, *packed_iter;
 	struct files_ref_iterator *iter;
@@ -2042,7 +2028,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	int attempts_remaining = 3;
 	int resolved;
 
-	files_assert_main_repository(refs, "lock_ref_sha1_basic");
 	assert(err);
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
@@ -2190,8 +2175,6 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	files_assert_main_repository(refs, "lock_packed_refs");
-
 	if (!timeout_configured) {
 		git_config_get_int("core.packedrefstimeout", &timeout_value);
 		timeout_configured = 1;
@@ -2231,8 +2214,6 @@ static int commit_packed_refs(struct files_ref_store *refs)
 	int save_errno = 0;
 	FILE *out;
 
-	files_assert_main_repository(refs, "commit_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 
@@ -2264,8 +2245,6 @@ static void rollback_packed_refs(struct files_ref_store *refs)
 	struct packed_ref_cache *packed_ref_cache =
 		get_packed_ref_cache(refs);
 
-	files_assert_main_repository(refs, "rollback_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 	rollback_lock_file(packed_ref_cache->lock);
@@ -2411,7 +2390,7 @@ static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "pack_refs");
+		files_downcast(ref_store, "pack_refs");
 	struct pack_refs_cb_data cbdata;
 
 	memset(&cbdata, 0, sizeof(cbdata));
@@ -2444,7 +2423,6 @@ static int repack_without_refs(struct files_ref_store *refs,
 	struct string_list_item *refname;
 	int ret, needs_repacking = 0, removed = 0;
 
-	files_assert_main_repository(refs, "repack_without_refs");
 	assert(err);
 
 	/* Look for a packed ref */
@@ -2512,7 +2490,7 @@ static int files_delete_refs(struct ref_store *ref_store,
 			     struct string_list *refnames, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_refs");
+		files_downcast(ref_store, "delete_refs");
 	struct strbuf err = STRBUF_INIT;
 	int i, result = 0;
 
@@ -2619,7 +2597,7 @@ static int files_verify_refname_available(struct ref_store *ref_store,
 					  struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "verify_refname_available");
+		files_downcast(ref_store, "verify_refname_available");
 	struct ref_dir *packed_refs = get_packed_refs(refs);
 	struct ref_dir *loose_refs = get_loose_refs(refs);
 
@@ -2644,7 +2622,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			    const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "rename_ref");
+		files_downcast(ref_store, "rename_ref");
 	unsigned char sha1[20], orig_sha1[20];
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
@@ -2866,7 +2844,7 @@ static int files_create_reflog(struct ref_store *ref_store,
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_reflog");
+		files_downcast(ref_store, "create_reflog");
 
 	ret = log_ref_setup(refs, refname, &sb, err, force_create);
 	strbuf_release(&sb);
@@ -3004,8 +2982,6 @@ static int commit_ref_update(struct files_ref_store *refs,
 			     const unsigned char *sha1, const char *logmsg,
 			     struct strbuf *err)
 {
-	files_assert_main_repository(refs, "commit_ref_update");
-
 	clear_loose_ref_cache(refs);
 	if (log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
 			  sha1, logmsg, 0, err)) {
@@ -3114,7 +3090,7 @@ static int files_create_symref(struct ref_store *ref_store,
 			       const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_symref");
+		files_downcast(ref_store, "create_symref");
 	struct strbuf err = STRBUF_INIT;
 	struct ref_lock *lock;
 	int ret;
@@ -3140,7 +3116,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
+		files_downcast(get_ref_store(NULL), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3178,7 +3154,7 @@ static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_exists");
+		files_downcast(ref_store, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
@@ -3193,7 +3169,7 @@ static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_reflog");
+		files_downcast(ref_store, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
@@ -3248,7 +3224,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
+		files_downcast(ref_store, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
@@ -3356,7 +3332,7 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent");
+		files_downcast(ref_store, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
@@ -3444,7 +3420,7 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_iterator_begin");
+		files_downcast(ref_store, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
@@ -3656,8 +3632,6 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 	int ret;
 	struct ref_lock *lock;
 
-	files_assert_main_repository(refs, "lock_ref_for_update");
-
 	if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
 		update->flags |= REF_DELETING;
 
@@ -3782,7 +3756,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 				    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "ref_transaction_commit");
+		files_downcast(ref_store, "ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
@@ -3956,7 +3930,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 					    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "initial_ref_transaction_commit");
+		files_downcast(ref_store, "initial_ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
@@ -4078,7 +4052,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			       void *policy_cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_expire");
+		files_downcast(ref_store, "reflog_expire");
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
@@ -4183,8 +4157,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "init_db");
+	struct files_ref_store *refs = files_downcast(ref_store, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
 	/*
-- 
2.11.0.157.gd943d85

Re: [PATCH 10/11] files-backend: remove submodule_allowed from files_downcast()

[Stefan Beller]

On Mon, Feb 13, 2017 at 7:20 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> Since submodule or not is irrelevant to files-backend after the last
> patch, remove the parameter from files_downcast() and kill
> files_assert_main_repository().
>
> PS. This implies that all ref operations are allowed for submodules. But
> we may need to look more closely to see if that's really true...
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---

Looks good,
Stefan

[PATCH 11/11] refs: split and make get_*_ref_store() public API

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 59 ++++++++++++++++++++++++++++++----------------------
 refs.h               | 13 ++++++++++++
 refs/files-backend.c |  2 +-
 refs/refs-internal.h | 12 -----------
 4 files changed, 48 insertions(+), 38 deletions(-)

diff --git a/refs.c b/refs.c
index 9ac194945..48350da87 100644
--- a/refs.c
+++ b/refs.c
@@ -1160,7 +1160,7 @@ int head_ref(each_ref_fn fn, void *cb_data)
 static int do_for_each_ref(const char *submodule, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(submodule);
+	struct ref_store *refs = get_submodule_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
@@ -1304,7 +1304,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->init_db(refs, err);
 }
@@ -1312,7 +1312,7 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_ref_store(NULL), refname,
+	return resolve_ref_recursively(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1333,10 +1333,10 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
 		/* We need to strip off one or more trailing slashes */
 		char *stripped = xmemdupz(submodule, len);
 
-		refs = get_ref_store(stripped);
+		refs = get_submodule_ref_store(stripped);
 		free(stripped);
 	} else {
-		refs = get_ref_store(submodule);
+		refs = get_submodule_ref_store(submodule);
 	}
 
 	if (!refs)
@@ -1491,15 +1491,24 @@ static struct ref_store *init_submodule_ref_store(const char *path)
 	return refs;
 }
 
-struct ref_store *get_ref_store(const char *submodule)
+struct ref_store *get_main_ref_store(void)
 {
 	struct ref_store *refs;
 
-	if (!submodule || !*submodule) {
-		refs = lookup_ref_store(NULL);
+	refs = lookup_ref_store(NULL);
 
-		if (!refs)
-			refs = ref_store_init(NULL, NULL);
+	if (!refs)
+		refs = ref_store_init(NULL, NULL);
+
+	return refs;
+}
+
+struct ref_store *get_submodule_ref_store(const char *submodule)
+{
+	struct ref_store *refs;
+
+	if (!submodule || !*submodule) {
+		return get_main_ref_store();
 	} else {
 		refs = lookup_ref_store(submodule);
 
@@ -1519,14 +1528,14 @@ void base_ref_store_init(struct ref_store *refs,
 /* backend functions */
 int pack_refs(unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->pack_refs(refs, flags);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->peel_ref(refs, refname, sha1);
 }
@@ -1534,7 +1543,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_symref(refs, ref_target, refs_heads_master,
 				       logmsg);
@@ -1543,7 +1552,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1553,14 +1562,14 @@ int verify_refname_available(const char *refname,
 			     const struct string_list *skip,
 			     struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
 }
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1571,7 +1580,7 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent_reverse(refs, refname,
 						     fn, cb_data);
@@ -1580,14 +1589,14 @@ int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_exists(refs, refname);
 }
@@ -1595,14 +1604,14 @@ int reflog_exists(const char *refname)
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_reflog(refs, refname);
 }
@@ -1614,7 +1623,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_expire(refs, refname, sha1, flags,
 				       prepare_fn, should_prune_fn,
@@ -1624,21 +1633,21 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
 int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_refs(refs, refnames, flags);
 }
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index 694784391..f5fba16c8 100644
--- a/refs.h
+++ b/refs.h
@@ -553,4 +553,17 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 
 int ref_storage_backend_exists(const char *name);
 
+/*
+ * Return the ref_store instance for the specified submodule. For the
+ * main repository, use submodule==NULL; such a call cannot fail. For
+ * a submodule, the submodule must exist and be a nonbare repository,
+ * otherwise return NULL. If the requested reference store has not yet
+ * been initialized, initialize it first.
+ *
+ * For backwards compatibility, submodule=="" is treated the same as
+ * submodule==NULL.
+ */
+struct ref_store *get_submodule_ref_store(const char *submodule);
+struct ref_store *get_main_ref_store(void);
+
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 2fb270b6f..eab156733 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3116,7 +3116,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), "set_head_symref");
+		files_downcast(get_main_ref_store(), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index d7112770d..cb6882779 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -634,18 +634,6 @@ struct ref_store {
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-/*
- * Return the ref_store instance for the specified submodule. For the
- * main repository, use submodule==NULL; such a call cannot fail. For
- * a submodule, the submodule must exist and be a nonbare repository,
- * otherwise return NULL. If the requested reference store has not yet
- * been initialized, initialize it first.
- *
- * For backwards compatibility, submodule=="" is treated the same as
- * submodule==NULL.
- */
-struct ref_store *get_ref_store(const char *submodule);
-
 const char *resolve_ref_recursively(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
-- 
2.11.0.157.gd943d85

Re: [PATCH 11/11] refs: split and make get_*_ref_store() public API

[Stefan Beller]

>
> +/*
> + * Return the ref_store instance for the specified submodule. For the
> + * main repository, use submodule==NULL; such a call cannot fail.

So now we have both a get_main as well as a get_submodule function,
but the submodule function can return the main as well?

I'd rather see this as a BUG; or asking another way:
What is the difference between get_submodule_ref_store(NULL)
and get_main_ref_store() ?

As you went through all call sites (by renaming the function), we'd
be able to tell that there is no caller with NULL, or is it?

Stefan

> For
> + * a submodule, the submodule must exist and be a nonbare repository,
> + * otherwise return NULL. If the requested reference store has not yet
> + * been initialized, initialize it first.
> + *
> + * For backwards compatibility, submodule=="" is treated the same as
> + * submodule==NULL.
> + */
> +struct ref_store *get_submodule_ref_store(const char *submodule);
> +struct ref_store *get_main_ref_store(void);

Re: [PATCH 11/11] refs: split and make get_*_ref_store() public API

[Duy Nguyen]

On Tue, Feb 14, 2017 at 6:55 AM, Stefan Beller <sbeller@google.com> wrote:
>>
>> +/*
>> + * Return the ref_store instance for the specified submodule. For the
>> + * main repository, use submodule==NULL; such a call cannot fail.
>
> So now we have both a get_main as well as a get_submodule function,
> but the submodule function can return the main as well?
>
> I'd rather see this as a BUG; or asking another way:
> What is the difference between get_submodule_ref_store(NULL)
> and get_main_ref_store() ?

Technical debts :) In order to do that, we need to make sure
_submodule() never takes NULL as main repo. But current code does. On
example is revision.c where submodule==NULL is the main repo. In the
end, I agree that get_submodule_ref_store(NULL) should be a bug.

> As you went through all call sites (by renaming the function), we'd
> be able to tell that there is no caller with NULL, or is it?

Direct call sites are just middle men though, e.g.
for_each_ref_submodule(). I'll attempt to clean this up at some point
in future (probably at the same time I attempt to kill *_submodule ref
api). But I think for now I'll just put a TODO or FIXME comment here.
-- 
Duy

Re: [PATCH 11/11] refs: split and make get_*_ref_store() public API

[Junio C Hamano]

Duy Nguyen <pclouds@gmail.com> writes:

> Direct call sites are just middle men though, e.g.
> for_each_ref_submodule(). I'll attempt to clean this up at some point
> in future (probably at the same time I attempt to kill *_submodule ref
> api). But I think for now I'll just put a TODO or FIXME comment here.

So we'd have get_*_ref_store() for various cases and then will have
a unifying for_each_ref_in_refstore() that takes a ref-store, which
supersedes all the ad-hoc iterators like for_each_ref_submodule(),
for_each_namespaced_ref(), etc?

That's a very sensible longer-term goal, methinks.

I am wondering what we should do to for_each_{tag,branch,...}_ref().  
Would that become

	ref_store = get_ref_main_store();
	tag_ref_store = filter_ref_store(ref_store, "refs/tags/");
	for_each_ref_in_refstore(tag_ref_store, ...);

or do you plan to have some other pattern?

Re: [PATCH 11/11] refs: split and make get_*_ref_store() public API

[Duy Nguyen]

On Wed, Feb 15, 2017 at 1:24 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Duy Nguyen <pclouds@gmail.com> writes:
>
>> Direct call sites are just middle men though, e.g.
>> for_each_ref_submodule(). I'll attempt to clean this up at some point
>> in future (probably at the same time I attempt to kill *_submodule ref
>> api). But I think for now I'll just put a TODO or FIXME comment here.
>
> So we'd have get_*_ref_store() for various cases and then will have
> a unifying for_each_ref_in_refstore() that takes a ref-store, which
> supersedes all the ad-hoc iterators like for_each_ref_submodule(),
> for_each_namespaced_ref(), etc?
>
> That's a very sensible longer-term goal, methinks.

Ah I forgot about ref namespace. I'll need to try something out in that area.

> I am wondering what we should do to for_each_{tag,branch,...}_ref().
> Would that become
>
>         ref_store = get_ref_main_store();
>         tag_ref_store = filter_ref_store(ref_store, "refs/tags/");
>         for_each_ref_in_refstore(tag_ref_store, ...);
>
> or do you plan to have some other pattern?

Long term, I think that's what Mike wants. Though the filter_ref_store
might return an (opaque) iterator instead of a ref store and
for_each_refstore() becomes a thin wrapper around the iterator
interface.
-- 
Duy

Re: [PATCH 11/11] refs: split and make get_*_ref_store() public API

[Junio C Hamano]

Duy Nguyen <pclouds@gmail.com> writes:

> Long term, I think that's what Mike wants. Though the filter_ref_store
> might return an (opaque) iterator instead of a ref store and
> for_each_refstore() becomes a thin wrapper around the iterator
> interface.

Ah, yes, an iterator would be a lot more suitable abstraction there.

Thanks.

Re: [PATCH 11/11] refs: split and make get_*_ref_store() public API

[Stefan Beller]

On Tue, Feb 14, 2017 at 2:04 AM, Duy Nguyen <pclouds@gmail.com> wrote:
> On Tue, Feb 14, 2017 at 6:55 AM, Stefan Beller <sbeller@google.com> wrote:
>>>
>>> +/*
>>> + * Return the ref_store instance for the specified submodule. For the
>>> + * main repository, use submodule==NULL; such a call cannot fail.
>>
>> So now we have both a get_main as well as a get_submodule function,
>> but the submodule function can return the main as well?
>>
>> I'd rather see this as a BUG; or asking another way:
>> What is the difference between get_submodule_ref_store(NULL)
>> and get_main_ref_store() ?
>
> Technical debts :) In order to do that, we need to make sure
> _submodule() never takes NULL as main repo. But current code does. On
> example is revision.c where submodule==NULL is the main repo. In the
> end, I agree that get_submodule_ref_store(NULL) should be a bug.
>
>> As you went through all call sites (by renaming the function), we'd
>> be able to tell that there is no caller with NULL, or is it?
>
> Direct call sites are just middle men though, e.g.
> for_each_ref_submodule(). I'll attempt to clean this up at some point
> in future (probably at the same time I attempt to kill *_submodule ref
> api). But I think for now I'll just put a TODO or FIXME comment here.

ok, fine with me.

My line of thinking when originally responding was to put the FIXME
comment at the caller site, and there we'd differentiate between the
two cases and call the appropriate function.

> --
> Duy

[PATCH v2 00/16] Remove submodule from files-backend.c

[Nguyễn Thái Ngọc Duy]

[-- Attachment #1: Type: plain, Size: 3039 bytes --]

[PATCH v2 01/16] refs-internal.c: make files_log_ref_write() static

[Nguyễn Thái Ngọc Duy]

Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
but probably never used outside refs-internal.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 3 +++
 refs/refs-internal.h | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index cdb6b8ff5..75565c3aa 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+			       const unsigned char *new_sha1, const char *msg,
+			       int flags, struct strbuf *err);
 
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 33adbf93b..59e65958a 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -222,10 +222,6 @@ struct ref_transaction {
 	enum ref_transaction_state state;
 };
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err);
-
 /*
  * Check for entries in extras that are within the specified
  * directory, where dirname is a reference directory name including
-- 
2.11.0.157.gd943d85

[PATCH v2 02/16] files-backend: convert git_path() to strbuf_git_path()

[Nguyễn Thái Ngọc Duy]

git_path() and friends are going to be killed in files-backend.c in near
future. And because there's a risk with overwriting buffer in
git_path(), let's convert them all to strbuf_git_path(). We'll have
easier time killing/converting strbuf_git_path() then because we won't
have to worry about memory management again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 111 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 89 insertions(+), 22 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 75565c3aa..f0c878b92 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2169,6 +2169,8 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	static int timeout_configured = 0;
 	static int timeout_value = 1000;
 	struct packed_ref_cache *packed_ref_cache;
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
 
 	files_assert_main_repository(refs, "lock_packed_refs");
 
@@ -2177,10 +2179,13 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	if (hold_lock_file_for_update_timeout(
-			    &packlock, git_path("packed-refs"),
-			    flags, timeout_value) < 0)
+	strbuf_git_path(&sb, "packed-refs");
+	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
+						flags, timeout_value);
+	strbuf_release(&sb);
+	if (ret < 0)
 		return -1;
+
 	/*
 	 * Get the current packed-refs while holding the lock.  If the
 	 * packed-refs file has been modified since we last read it,
@@ -2335,6 +2340,9 @@ static void try_remove_empty_parents(char *name)
 	for (q = p; *q; q++)
 		;
 	while (1) {
+		struct strbuf sb = STRBUF_INIT;
+		int ret;
+
 		while (q > p && *q != '/')
 			q--;
 		while (q > p && *(q-1) == '/')
@@ -2342,7 +2350,10 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		if (rmdir(git_path("%s", name)))
+		strbuf_git_path(&sb, "%s", name);
+		ret = rmdir(sb.buf);
+		strbuf_release(&sb);
+		if (ret)
 			break;
 	}
 }
@@ -2431,7 +2442,11 @@ static int repack_without_refs(struct files_ref_store *refs,
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(refs, 0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "packed-refs");
+		unable_to_lock_message(sb.buf, errno, err);
+		strbuf_release(&sb);
 		return -1;
 	}
 	packed = get_packed_refs(refs);
@@ -2529,8 +2544,10 @@ static int rename_tmp_log(const char *newrefname)
 {
 	int attempts_remaining = 4;
 	struct strbuf path = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
 	int ret = -1;
 
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
  retry:
 	strbuf_reset(&path);
 	strbuf_git_path(&path, "logs/%s", newrefname);
@@ -2546,7 +2563,7 @@ static int rename_tmp_log(const char *newrefname)
 		goto out;
 	}
 
-	if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
+	if (rename(tmp_renamed_log.buf, path.buf)) {
 		if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
 			/*
 			 * rename(a, b) when b is an existing
@@ -2574,6 +2591,7 @@ static int rename_tmp_log(const char *newrefname)
 	ret = 0;
 out:
 	strbuf_release(&path);
+	strbuf_release(&tmp_renamed_log);
 	return ret;
 }
 
@@ -2614,9 +2632,15 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
-	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+	struct strbuf sb_oldref = STRBUF_INIT;
+	struct strbuf sb_newref = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
+	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	log = !lstat(sb_oldref.buf, &loginfo);
+	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2630,7 +2654,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
+	if (ret)
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
@@ -2709,13 +2738,19 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
+	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
+	strbuf_release(&sb_newref);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
 
 	return 1;
 }
@@ -3111,22 +3146,32 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
+	int ret;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_exists");
 
-	return !lstat(git_path("logs/%s", refname), &st) &&
-		S_ISREG(st.st_mode);
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "delete_reflog");
 
-	return remove_path(git_path("logs/%s", refname));
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = remove_path(sb.buf);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
@@ -3181,7 +3226,9 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3287,7 +3334,9 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3369,12 +3418,15 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 {
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
+	struct strbuf sb = STRBUF_INIT;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_iterator_begin");
 
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	iter->dir_iterator = dir_iterator_begin(git_path("logs"));
+	strbuf_git_path(&sb, "logs");
+	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	strbuf_release(&sb);
 	return ref_iterator;
 }
 
@@ -3843,8 +3895,13 @@ static int files_transaction_commit(struct ref_store *ref_store,
 		ret = TRANSACTION_GENERIC_ERROR;
 		goto cleanup;
 	}
-	for_each_string_list_item(ref_to_delete, &refs_to_delete)
-		unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
+	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		unlink_or_warn(sb.buf);
+		strbuf_release(&sb);
+	}
 	clear_loose_ref_cache(refs);
 
 cleanup:
@@ -4098,18 +4155,28 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct strbuf sb = STRBUF_INIT;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "init_db");
 
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	strbuf_git_path(&sb, "refs/heads");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
+	strbuf_git_path(&sb, "refs/tags");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		strbuf_git_path(&sb, "refs/heads");
+		adjust_shared_perm(sb.buf);
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "refs/tags");
+		adjust_shared_perm(sb.buf);
 	}
+	strbuf_release(&sb);
 	return 0;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v2 03/16] files-backend: add files_path()

[Nguyễn Thái Ngọc Duy]

This will be the replacement for both git_path() and git_path_submodule()
in this file. The idea is backend takes a git path and use that,
oblivious of submodule, linked worktrees and such.

This is the middle step towards that. Eventually the "submodule" field
in 'struct files_ref_store' should be replace by "gitdir". And a
compound ref_store is created to combine two files backends together,
one represents the shared refs in $GIT_COMMON_DIR, one per-worktree. At
that point, files_path() becomes a wrapper of strbuf_vaddf().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index f0c878b92..abb8a95e0 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -930,6 +930,24 @@ struct files_ref_store {
 /* Lock used for the main packed-refs file: */
 static struct lock_file packlock;
 
+__attribute__((format (printf, 3, 4)))
+static void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		       const char *fmt, ...)
+{
+	struct strbuf tmp = STRBUF_INIT;
+	va_list vap;
+
+	va_start(vap, fmt);
+	strbuf_vaddf(&tmp, fmt, vap);
+	va_end(vap);
+	if (refs->submodule)
+		strbuf_git_path_submodule(sb, refs->submodule,
+					  "%s", tmp.buf);
+	else
+		strbuf_git_path(sb, "%s", tmp.buf);
+	strbuf_release(&tmp);
+}
+
 /*
  * Increment the reference count of *packed_refs.
  */
-- 
2.11.0.157.gd943d85

[PATCH v2 04/16] files-backend: replace *git_path*() with files_path()

[Nguyễn Thái Ngọc Duy]

This centralizes all path rewriting of files-backend.c in one place so
we have easier time removing the path rewriting later. There could be
some hidden indirect git_path() though, I didn't audit the code to the
bottom.

Side note: set_worktree_head_symref() is a bad boy and should not be in
files-backend.c (probably should not exist in the first place). But
we'll leave it there until we have better multi-worktree support in refs
before we update it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 185 ++++++++++++++++++++++++++-------------------------
 1 file changed, 94 insertions(+), 91 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index abb8a95e0..24f5bf7f1 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,7 +165,8 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
-static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int files_log_ref_write(struct files_ref_store *refs,
+			       const char *refname, const unsigned char *old_sha1,
 			       const unsigned char *new_sha1, const char *msg,
 			       int flags, struct strbuf *err);
 
@@ -1178,12 +1179,10 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
 {
 	char *packed_refs_file;
+	struct strbuf sb = STRBUF_INIT;
 
-	if (refs->submodule)
-		packed_refs_file = git_pathdup_submodule(refs->submodule,
-							 "packed-refs");
-	else
-		packed_refs_file = git_pathdup("packed-refs");
+	files_path(refs, &sb, "packed-refs");
+	packed_refs_file = strbuf_detach(&sb, NULL);
 
 	if (refs->packed &&
 	    !stat_validity_check(&refs->packed->validity, packed_refs_file))
@@ -1249,10 +1248,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 	size_t path_baselen;
 	int err = 0;
 
-	if (refs->submodule)
-		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
-	else
-		strbuf_git_path(&path, "%s", dirname);
+	files_path(refs, &path, "%s", dirname);
 	path_baselen = path.len;
 
 	if (err) {
@@ -1394,10 +1390,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	*type = 0;
 	strbuf_reset(&sb_path);
 
-	if (refs->submodule)
-		strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
-	else
-		strbuf_git_path(&sb_path, "%s", refname);
+	files_path(refs, &sb_path, "%s", refname);
 
 	path = sb_path.buf;
 
@@ -1585,7 +1578,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	*lock_p = lock = xcalloc(1, sizeof(*lock));
 
 	lock->ref_name = xstrdup(refname);
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 
 retry:
 	switch (safe_create_leading_directories(ref_file.buf)) {
@@ -2052,7 +2045,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	if (flags & REF_DELETING)
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
 					lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
@@ -2197,7 +2190,7 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	strbuf_git_path(&sb, "packed-refs");
+	files_path(refs, &sb, "packed-refs");
 	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
 						flags, timeout_value);
 	strbuf_release(&sb);
@@ -2343,7 +2336,7 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
  * Remove empty parents, but spare refs/ and immediate subdirs.
  * Note: munges *name.
  */
-static void try_remove_empty_parents(char *name)
+static void try_remove_empty_parents(struct files_ref_store *refs, char *name)
 {
 	char *p, *q;
 	int i;
@@ -2368,7 +2361,7 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		strbuf_git_path(&sb, "%s", name);
+		files_path(refs, &sb, "%s", name);
 		ret = rmdir(sb.buf);
 		strbuf_release(&sb);
 		if (ret)
@@ -2377,7 +2370,7 @@ static void try_remove_empty_parents(char *name)
 }
 
 /* make sure nobody touched the ref, and unlink */
-static void prune_ref(struct ref_to_prune *r)
+static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -2397,13 +2390,13 @@ static void prune_ref(struct ref_to_prune *r)
 	}
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
-	try_remove_empty_parents(r->name);
+	try_remove_empty_parents(refs, r->name);
 }
 
-static void prune_refs(struct ref_to_prune *r)
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	while (r) {
-		prune_ref(r);
+		prune_ref(refs, r);
 		r = r->next;
 	}
 }
@@ -2426,7 +2419,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 	if (commit_packed_refs(refs))
 		die_errno("unable to overwrite old ref-pack file");
 
-	prune_refs(cbdata.ref_to_prune);
+	prune_refs(refs, cbdata.ref_to_prune);
 	return 0;
 }
 
@@ -2462,7 +2455,7 @@ static int repack_without_refs(struct files_ref_store *refs,
 	if (lock_packed_refs(refs, 0)) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "packed-refs");
+		files_path(refs, &sb, "packed-refs");
 		unable_to_lock_message(sb.buf, errno, err);
 		strbuf_release(&sb);
 		return -1;
@@ -2558,17 +2551,17 @@ static int files_delete_refs(struct ref_store *ref_store,
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 {
 	int attempts_remaining = 4;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf tmp_renamed_log = STRBUF_INIT;
 	int ret = -1;
 
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
  retry:
 	strbuf_reset(&path);
-	strbuf_git_path(&path, "logs/%s", newrefname);
+	files_path(refs, &path, "logs/%s", newrefname);
 	switch (safe_create_leading_directories_const(path.buf)) {
 	case SCLD_OK:
 		break; /* success */
@@ -2656,7 +2649,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	log = !lstat(sb_oldref.buf, &loginfo);
 	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
@@ -2672,8 +2665,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
 	strbuf_release(&sb_oldref);
 	strbuf_release(&tmp_renamed_log);
@@ -2700,7 +2693,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			struct strbuf path = STRBUF_INIT;
 			int result;
 
-			strbuf_git_path(&path, "%s", newrefname);
+			files_path(refs, &path, "%s", newrefname);
 			result = remove_empty_directories(&path);
 			strbuf_release(&path);
 
@@ -2714,7 +2707,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 		}
 	}
 
-	if (log && rename_tmp_log(newrefname))
+	if (log && rename_tmp_log(refs, newrefname))
 		goto rollback;
 
 	logmoved = log;
@@ -2756,12 +2749,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_newref, "logs/%s", newrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
 	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
@@ -2817,11 +2810,13 @@ static int commit_ref(struct ref_lock *lock)
  * should_autocreate_reflog returns non-zero.  Otherwise, create it
  * regardless of the ref name.  Fill in *err and return -1 on failure.
  */
-static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
+static int log_ref_setup(struct files_ref_store *refs, const char *refname,
+			 struct strbuf *logfile, struct strbuf *err,
+			 int force_create)
 {
 	int logfd, oflags = O_APPEND | O_WRONLY;
 
-	strbuf_git_path(logfile, "logs/%s", refname);
+	files_path(refs, logfile, "logs/%s", refname);
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (safe_create_leading_directories(logfile->buf) < 0) {
 			strbuf_addf(err, "unable to create directory for '%s': "
@@ -2864,11 +2859,10 @@ static int files_create_reflog(struct ref_store *ref_store,
 {
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "create_reflog");
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "create_reflog");
-
-	ret = log_ref_setup(refname, &sb, err, force_create);
+	ret = log_ref_setup(refs, refname, &sb, err, force_create);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -2899,7 +2893,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
+static int log_ref_write_1(struct files_ref_store *refs,
+			   const char *refname, const unsigned char *old_sha1,
 			   const unsigned char *new_sha1, const char *msg,
 			   struct strbuf *logfile, int flags,
 			   struct strbuf *err)
@@ -2909,7 +2904,7 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
+	result = log_ref_setup(refs, refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
 
 	if (result)
 		return result;
@@ -2933,21 +2928,23 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int log_ref_write(struct files_ref_store *refs,
+			 const char *refname, const unsigned char *old_sha1,
 			 const unsigned char *new_sha1, const char *msg,
 			 int flags, struct strbuf *err)
 {
-	return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
-				   err);
+	return files_log_ref_write(refs, refname, old_sha1, new_sha1,
+				   msg, flags, err);
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+int files_log_ref_write(struct files_ref_store *refs,
+			const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)
 {
 	struct strbuf sb = STRBUF_INIT;
-	int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
-				  err);
+	int ret = log_ref_write_1(refs, refname, old_sha1, new_sha1, msg,
+				  &sb, flags, err);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -3004,7 +3001,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
+	if (log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
+			  sha1, logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
 			    lock->ref_name, old_msg);
@@ -3035,8 +3033,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
-					  logmsg, 0, &log_err)) {
+			if (log_ref_write(refs, "HEAD", lock->old_oid.hash,
+					  sha1, logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
 			}
@@ -3068,23 +3066,26 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 	return ret;
 }
 
-static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+static void update_symref_reflog(struct files_ref_store *refs,
+				 struct ref_lock *lock, const char *refname,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
 	if (logmsg && !read_ref(target, new_sha1) &&
-	    log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
+	    log_ref_write(refs, refname, lock->old_oid.hash,
+			  new_sha1, logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
 }
 
-static int create_symref_locked(struct ref_lock *lock, const char *refname,
+static int create_symref_locked(struct files_ref_store *refs,
+				struct ref_lock *lock, const char *refname,
 				const char *target, const char *logmsg)
 {
 	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(lock, refname, target, logmsg);
+		update_symref_reflog(refs, lock, refname, target, logmsg);
 		return 0;
 	}
 
@@ -3092,7 +3093,7 @@ static int create_symref_locked(struct ref_lock *lock, const char *refname,
 		return error("unable to fdopen %s: %s",
 			     lock->lk->tempfile.filename.buf, strerror(errno));
 
-	update_symref_reflog(lock, refname, target, logmsg);
+	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
 	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
@@ -3121,13 +3122,19 @@ static int files_create_symref(struct ref_store *ref_store,
 		return -1;
 	}
 
-	ret = create_symref_locked(lock, refname, target, logmsg);
+	ret = create_symref_locked(refs, lock, refname, target, logmsg);
 	unlock_ref(lock);
 	return ret;
 }
 
 int set_worktree_head_symref(const char *gitdir, const char *target)
 {
+	/*
+	 * FIXME: this obviously will not work well for future refs
+	 * backends. This function needs to die.
+	 */
+	struct files_ref_store *refs =
+		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3154,7 +3161,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	lock->lk = &head_lock;
 	lock->ref_name = xstrdup(head_rel);
 
-	ret = create_symref_locked(lock, head_rel, target, NULL);
+	ret = create_symref_locked(refs, lock, head_rel, target, NULL);
 
 	unlock_ref(lock); /* will free lock */
 	strbuf_release(&head_path);
@@ -3164,14 +3171,13 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_exists");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
 	strbuf_release(&sb);
 	return ret;
@@ -3180,13 +3186,12 @@ static int files_reflog_exists(struct ref_store *ref_store,
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "delete_reflog");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = remove_path(sb.buf);
 	strbuf_release(&sb);
 	return ret;
@@ -3236,15 +3241,14 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     each_reflog_ent_fn fn,
 					     void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
 	int ret = 0, at_tail = 1;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3345,14 +3349,13 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     const char *refname,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3434,15 +3437,14 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_iterator_begin");
-
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	strbuf_git_path(&sb, "logs");
+	files_path(refs, &sb, "logs");
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
 	strbuf_release(&sb);
 	return ref_iterator;
@@ -3866,8 +3868,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (log_ref_write(lock->ref_name, lock->old_oid.hash,
-					  update->new_sha1,
+			if (log_ref_write(refs, lock->ref_name,
+					  lock->old_oid.hash, update->new_sha1,
 					  update->msg, update->flags, err)) {
 				char *old_msg = strbuf_detach(err, NULL);
 
@@ -3916,7 +3918,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		files_path(refs, &sb, "logs/%s", ref_to_delete->string);
 		unlink_or_warn(sb.buf);
 		strbuf_release(&sb);
 	}
@@ -4078,6 +4080,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	int status = 0;
 	int type;
 	struct strbuf err = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 
 	memset(&cb, 0, sizeof(cb));
 	cb.flags = flags;
@@ -4102,7 +4105,8 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		return 0;
 	}
 
-	log_file = git_pathdup("logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
+	log_file = strbuf_detach(&sb, NULL);
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 		/*
 		 * Even though holding $GIT_DIR/logs/$reflog.lock has
@@ -4173,25 +4177,24 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "init_db");
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	strbuf_git_path(&sb, "refs/heads");
+	files_path(refs, &sb, "refs/heads");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
-	strbuf_git_path(&sb, "refs/tags");
+	files_path(refs, &sb, "refs/tags");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		strbuf_git_path(&sb, "refs/heads");
+		files_path(refs, &sb, "refs/heads");
 		adjust_shared_perm(sb.buf);
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "refs/tags");
+		files_path(refs, &sb, "refs/tags");
 		adjust_shared_perm(sb.buf);
 	}
 	strbuf_release(&sb);
-- 
2.11.0.157.gd943d85

Re: [PATCH v2 04/16] files-backend: replace *git_path*() with files_path()

[Michael Haggerty]

On 02/16/2017 12:48 PM, Nguyễn Thái Ngọc Duy wrote:
> This centralizes all path rewriting of files-backend.c in one place so
> we have easier time removing the path rewriting later. There could be
> some hidden indirect git_path() though, I didn't audit the code to the
> bottom.

Almost all of the calls to `files_path()` [1] take one of the following
forms:

* `files_path(refs, &sb, "packed-refs")`
* `files_path(refs, &sb, "%s", refname)`
* `files_path(refs, &sb, "logs/%s", refname)`

(though sometimes `refname` is not the name of a reference but rather
the name of a directory containing references, like "refs/heads").

This suggests to me that it would be more natural to have three
functions, `files_packed_refs_path()`, `files_loose_ref_path()`, and
`files_reflog_path()`, with no `fmt` arguments. Aside from making the
callers a bit simpler and the implementation of each of the three
functions simpler (they wouldn't have to deal with variable argument
lists), at the cost of needing three similar functions.

But I think the split would also be advantageous from a design point of
view. The relative path locations of loose reference files, reflog
files, and the packed-refs file is kind of a coincidence, and it would
be advantageous to encode that policy in three functions rather than
continuing to spread knowledge of those assumptions around.

It would also make it easier to switch to a new system of encoding
reference names, for example so that reference names that differ only in
case can be stored on a case-insensitive filesystem, or to store reflogs
using a naming scheme that is not susceptible to D/F conflicts so that
we can retain reflogs for deleted references.

Michael

[1] The only exception I see is one call `files_path(refs, &sb,
"logs")`, which is a prelude to iterating over the reflog files. This is
actually an example of the code giving us a hint that the design is
wrong: if you iterate only over the directories under `git_path(logs)`,
you miss the reflogs for worktree references.

Re: [PATCH v2 04/16] files-backend: replace *git_path*() with files_path()

[Duy Nguyen]

On Mon, Feb 20, 2017 at 6:23 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/16/2017 12:48 PM, Nguyễn Thái Ngọc Duy wrote:
>> This centralizes all path rewriting of files-backend.c in one place so
>> we have easier time removing the path rewriting later. There could be
>> some hidden indirect git_path() though, I didn't audit the code to the
>> bottom.
>
> Almost all of the calls to `files_path()` [1] take one of the following
> forms:
>
> * `files_path(refs, &sb, "packed-refs")`
> * `files_path(refs, &sb, "%s", refname)`
> * `files_path(refs, &sb, "logs/%s", refname)`
>
> (though sometimes `refname` is not the name of a reference but rather
> the name of a directory containing references, like "refs/heads").
>
> This suggests to me that it would be more natural to have three
> functions, `files_packed_refs_path()`, `files_loose_ref_path()`, and
> `files_reflog_path()`, with no `fmt` arguments. Aside from making the
> callers a bit simpler and the implementation of each of the three
> functions simpler (they wouldn't have to deal with variable argument
> lists), at the cost of needing three similar functions.
>
> But I think the split would also be advantageous from a design point of
> view. The relative path locations of loose reference files, reflog
> files, and the packed-refs file is kind of a coincidence, and it would
> be advantageous to encode that policy in three functions rather than
> continuing to spread knowledge of those assumptions around.
>
> It would also make it easier to switch to a new system of encoding
> reference names, for example so that reference names that differ only in
> case can be stored on a case-insensitive filesystem, or to store reflogs
> using a naming scheme that is not susceptible to D/F conflicts so that
> we can retain reflogs for deleted references.

I agree. I didn't see it clearly at the beginning (and made several
mistakes in earlier iterations) but as you have seen files_path() the
separation is pretty clear there. I was going to do it when
introducing the "linked worktree" backend. But since you pointed it
out, I'll update it in this series too.

> Michael
>
> [1] The only exception I see is one call `files_path(refs, &sb,
> "logs")`, which is a prelude to iterating over the reflog files. This is
> actually an example of the code giving us a hint that the design is
> wrong: if you iterate only over the directories under `git_path(logs)`,
> you miss the reflogs for worktree references.

Oh yes, I had to fix the reflog iterator [1] exactly for that :)

[1] https://public-inbox.org/git/20170217141908.18012-14-pclouds@gmail.com/T/#u
-- 
Duy

[PATCH v2 05/16] refs.c: share is_per_worktree_ref() to files-backend.c

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 6 ------
 refs/refs-internal.h | 6 ++++++
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/refs.c b/refs.c
index 4f845798b..7a474198e 100644
--- a/refs.c
+++ b/refs.c
@@ -489,12 +489,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-static int is_per_worktree_ref(const char *refname)
-{
-	return !strcmp(refname, "HEAD") ||
-		starts_with(refname, "refs/bisect/");
-}
-
 static int is_pseudoref_syntax(const char *refname)
 {
 	const char *c;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 59e65958a..f4aed49f5 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -651,4 +651,10 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 				    int resolve_flags,
 				    unsigned char *sha1, int *flags);
 
+static inline int is_per_worktree_ref(const char *refname)
+{
+	return !strcmp(refname, "HEAD") ||
+		starts_with(refname, "refs/bisect/");
+}
+
 #endif /* REFS_REFS_INTERNAL_H */
-- 
2.11.0.157.gd943d85

[PATCH v2 06/16] refs-internal.h: correct is_per_worktree_ref()

[Nguyễn Thái Ngọc Duy]

All refs outside refs/ directory is per-worktree, not just HEAD.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/refs-internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index f4aed49f5..69d02b6ba 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -653,7 +653,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 
 static inline int is_per_worktree_ref(const char *refname)
 {
-	return !strcmp(refname, "HEAD") ||
+	return !starts_with(refname, "refs/") ||
 		starts_with(refname, "refs/bisect/");
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v2 07/16] files-backend: remove the use of git_path()

[Nguyễn Thái Ngọc Duy]

Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
deciding what goes where. The end goal is to pass $GIT_DIR only. A
refs "view" of a linked worktree is a logical ref store that combines
two files backends together.

(*) Not entirely true since strbuf_git_path_submodule() still does path
translation underneath. But that's for another patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 24f5bf7f1..74e31d041 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -924,6 +924,9 @@ struct files_ref_store {
 	 */
 	const char *submodule;
 
+	struct strbuf gitdir;
+	struct strbuf gitcommondir;
+
 	struct ref_entry *loose;
 	struct packed_ref_cache *packed;
 };
@@ -937,6 +940,7 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 {
 	struct strbuf tmp = STRBUF_INIT;
 	va_list vap;
+	const char *ref;
 
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
@@ -944,8 +948,12 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	if (refs->submodule)
 		strbuf_git_path_submodule(sb, refs->submodule,
 					  "%s", tmp.buf);
+	else if (is_per_worktree_ref(tmp.buf) ||
+		 (skip_prefix(tmp.buf, "logs/", &ref) &&
+		  is_per_worktree_ref(ref)))
+		strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
 	else
-		strbuf_git_path(sb, "%s", tmp.buf);
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
 	strbuf_release(&tmp);
 }
 
@@ -1004,7 +1012,15 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
-	refs->submodule = xstrdup_or_null(submodule);
+	strbuf_init(&refs->gitdir, 0);
+	strbuf_init(&refs->gitcommondir, 0);
+
+	if (submodule) {
+		refs->submodule = xstrdup(submodule);
+	} else {
+		strbuf_addstr(&refs->gitdir, get_git_dir());
+		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
+	}
 
 	return ref_store;
 }
-- 
2.11.0.157.gd943d85

[PATCH v2 08/16] refs.c: introduce get_main_ref_store()

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/refs.c b/refs.c
index 7a474198e..10994d992 100644
--- a/refs.c
+++ b/refs.c
@@ -1445,15 +1445,23 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
+static struct ref_store *get_main_ref_store(void)
+{
+	struct ref_store *refs;
+
+	if (main_ref_store)
+		return main_ref_store;
+
+	refs = ref_store_init(NULL);
+	return refs;
+}
+
 struct ref_store *get_ref_store(const char *submodule)
 {
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
-		refs = lookup_ref_store(NULL);
-
-		if (!refs)
-			refs = ref_store_init(NULL);
+		return get_main_ref_store();
 	} else {
 		refs = lookup_ref_store(submodule);
 
-- 
2.11.0.157.gd943d85

[PATCH v2 09/16] refs: rename lookup_ref_store() to lookup_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

With get_main_ref_store() being used inside get_ref_store(),
lookup_ref_store() is only used for submodule code path. Rename to
reflect that and delete dead code.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index 10994d992..ea13a5b86 100644
--- a/refs.c
+++ b/refs.c
@@ -1384,17 +1384,13 @@ static struct ref_store *main_ref_store;
 static struct hashmap submodule_ref_stores;
 
 /*
- * Return the ref_store instance for the specified submodule (or the
- * main repository if submodule is NULL). If that ref_store hasn't
- * been initialized yet, return NULL.
+ * Return the ref_store instance for the specified submodule. If that
+ * ref_store hasn't been initialized yet, return NULL.
  */
-static struct ref_store *lookup_ref_store(const char *submodule)
+static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 {
 	struct submodule_hash_entry *entry;
 
-	if (!submodule)
-		return main_ref_store;
-
 	if (!submodule_ref_stores.tablesize)
 		/* It's initialized on demand in register_ref_store(). */
 		return NULL;
@@ -1463,7 +1459,7 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
 	} else {
-		refs = lookup_ref_store(submodule);
+		refs = lookup_submodule_ref_store(submodule);
 
 		if (!refs) {
 			struct strbuf submodule_sb = STRBUF_INIT;
@@ -1474,7 +1470,6 @@ struct ref_store *get_ref_store(const char *submodule)
 			strbuf_release(&submodule_sb);
 		}
 	}
-
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v2 10/16] refs.c: flatten get_ref_store() a bit

[Nguyễn Thái Ngọc Duy]

This helps the future changes in this code. And because get_ref_store()
is destined to become get_submodule_ref_store(), the "get main store"
code path will be removed eventually. After this the patch to delete
that code will be cleaner.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/refs.c b/refs.c
index ea13a5b86..76a0e7b5a 100644
--- a/refs.c
+++ b/refs.c
@@ -1454,22 +1454,21 @@ static struct ref_store *get_main_ref_store(void)
 
 struct ref_store *get_ref_store(const char *submodule)
 {
+	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
-	} else {
-		refs = lookup_submodule_ref_store(submodule);
+	}
 
-		if (!refs) {
-			struct strbuf submodule_sb = STRBUF_INIT;
+	refs = lookup_submodule_ref_store(submodule);
+	if (refs)
+		return refs;
 
-			strbuf_addstr(&submodule_sb, submodule);
-			if (is_nonbare_repository_dir(&submodule_sb))
-				refs = ref_store_init(submodule);
-			strbuf_release(&submodule_sb);
-		}
-	}
+	strbuf_addstr(&submodule_sb, submodule);
+	if (is_nonbare_repository_dir(&submodule_sb))
+		refs = ref_store_init(submodule);
+	strbuf_release(&submodule_sb);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v2 11/16] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

This is the last function in this code (besides public API) that takes
submodule argument and handles both main/submodule cases. Break it down,
move main store registration in get_main_ref_store() and keep the rest
in register_submodule_ref_store().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/refs.c b/refs.c
index 76a0e7b5a..55a80a83d 100644
--- a/refs.c
+++ b/refs.c
@@ -1402,25 +1402,19 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 
 /*
  * Register the specified ref_store to be the one that should be used
- * for submodule (or the main repository if submodule is NULL). It is
- * a fatal error to call this function twice for the same submodule.
+ * for submodule. It is a fatal error to call this function twice for
+ * the same submodule.
  */
-static void register_ref_store(struct ref_store *refs, const char *submodule)
+static void register_submodule_ref_store(struct ref_store *refs,
+					 const char *submodule)
 {
-	if (!submodule) {
-		if (main_ref_store)
-			die("BUG: main_ref_store initialized twice");
-
-		main_ref_store = refs;
-	} else {
-		if (!submodule_ref_stores.tablesize)
-			hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
+	if (!submodule_ref_stores.tablesize)
+		hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
 
-		if (hashmap_put(&submodule_ref_stores,
-				alloc_submodule_hash_entry(submodule, refs)))
-			die("BUG: ref_store for submodule '%s' initialized twice",
-			    submodule);
-	}
+	if (hashmap_put(&submodule_ref_stores,
+			alloc_submodule_hash_entry(submodule, refs)))
+		die("BUG: ref_store for submodule '%s' initialized twice",
+		    submodule);
 }
 
 /*
@@ -1437,7 +1431,6 @@ static struct ref_store *ref_store_init(const char *submodule)
 		die("BUG: reference backend %s is unknown", be_name);
 
 	refs = be->init(submodule);
-	register_ref_store(refs, submodule);
 	return refs;
 }
 
@@ -1449,6 +1442,12 @@ static struct ref_store *get_main_ref_store(void)
 		return main_ref_store;
 
 	refs = ref_store_init(NULL);
+	if (refs) {
+		if (main_ref_store)
+			die("BUG: main_ref_store initialized twice");
+
+		main_ref_store = refs;
+	}
 	return refs;
 }
 
@@ -1469,6 +1468,9 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (is_nonbare_repository_dir(&submodule_sb))
 		refs = ref_store_init(submodule);
 	strbuf_release(&submodule_sb);
+
+	if (refs)
+		register_submodule_ref_store(refs, submodule);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v2 12/16] refs.c: make get_main_ref_store() public and use it

[Nguyễn Thái Ngọc Duy]

get_ref_store() will soon be renamed to get_submodule_ref_store().
Together with future get_worktree_ref_store(), the three functions
provide an appropriate ref store for different operation modes. New APIs
will be added to operate directly on ref stores.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 36 ++++++++++++++++++------------------
 refs.h |  2 ++
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/refs.c b/refs.c
index 55a80a83d..25f657a6f 100644
--- a/refs.c
+++ b/refs.c
@@ -1303,7 +1303,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->init_db(refs, err);
 }
@@ -1311,7 +1311,7 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_ref_store(NULL), refname,
+	return resolve_ref_recursively(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1434,7 +1434,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
-static struct ref_store *get_main_ref_store(void)
+struct ref_store *get_main_ref_store(void)
 {
 	struct ref_store *refs;
 
@@ -1483,14 +1483,14 @@ void base_ref_store_init(struct ref_store *refs,
 /* backend functions */
 int pack_refs(unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->pack_refs(refs, flags);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->peel_ref(refs, refname, sha1);
 }
@@ -1498,7 +1498,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_symref(refs, ref_target, refs_heads_master,
 				       logmsg);
@@ -1507,7 +1507,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1517,14 +1517,14 @@ int verify_refname_available(const char *refname,
 			     const struct string_list *skip,
 			     struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
 }
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1535,7 +1535,7 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent_reverse(refs, refname,
 						     fn, cb_data);
@@ -1544,14 +1544,14 @@ int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_exists(refs, refname);
 }
@@ -1559,14 +1559,14 @@ int reflog_exists(const char *refname)
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_reflog(refs, refname);
 }
@@ -1578,7 +1578,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_expire(refs, refname, sha1, flags,
 				       prepare_fn, should_prune_fn,
@@ -1588,21 +1588,21 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
 int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_refs(refs, refnames, flags);
 }
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index 694784391..f803528fc 100644
--- a/refs.h
+++ b/refs.h
@@ -553,4 +553,6 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 
 int ref_storage_backend_exists(const char *name);
 
+struct ref_store *get_main_ref_store(void);
+
 #endif /* REFS_H */
-- 
2.11.0.157.gd943d85

[PATCH v2 13/16] path.c: move some code out of strbuf_git_path_submodule()

[Nguyễn Thái Ngọc Duy]

refs is learning to avoid path rewriting that is done by
strbuf_git_path_submodule(). Factor out this code so it could be reused
by refs*

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 path.c      | 34 +++++++---------------------------
 submodule.c | 31 +++++++++++++++++++++++++++++++
 submodule.h |  1 +
 3 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/path.c b/path.c
index efcedafba..3451d2916 100644
--- a/path.c
+++ b/path.c
@@ -475,35 +475,16 @@ const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 static int do_submodule_path(struct strbuf *buf, const char *path,
 			     const char *fmt, va_list args)
 {
-	const char *git_dir;
 	struct strbuf git_submodule_common_dir = STRBUF_INIT;
 	struct strbuf git_submodule_dir = STRBUF_INIT;
-	const struct submodule *sub;
-	int err = 0;
+	int ret;
 
-	strbuf_addstr(buf, path);
-	strbuf_complete(buf, '/');
-	strbuf_addstr(buf, ".git");
-
-	git_dir = read_gitfile(buf->buf);
-	if (git_dir) {
-		strbuf_reset(buf);
-		strbuf_addstr(buf, git_dir);
-	}
-	if (!is_git_directory(buf->buf)) {
-		gitmodules_config();
-		sub = submodule_from_path(null_sha1, path);
-		if (!sub) {
-			err = SUBMODULE_PATH_ERR_NOT_CONFIGURED;
-			goto cleanup;
-		}
-		strbuf_reset(buf);
-		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
-	}
-
-	strbuf_addch(buf, '/');
-	strbuf_addbuf(&git_submodule_dir, buf);
+	ret = submodule_to_gitdir(&git_submodule_dir, path);
+	if (ret)
+		goto cleanup;
 
+	strbuf_complete(&git_submodule_dir, '/');
+	strbuf_addbuf(buf, &git_submodule_dir);
 	strbuf_vaddf(buf, fmt, args);
 
 	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
@@ -514,8 +495,7 @@ static int do_submodule_path(struct strbuf *buf, const char *path,
 cleanup:
 	strbuf_release(&git_submodule_dir);
 	strbuf_release(&git_submodule_common_dir);
-
-	return err;
+	return ret;
 }
 
 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
diff --git a/submodule.c b/submodule.c
index ece17315d..3ce589d55 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1335,3 +1335,34 @@ void prepare_submodule_repo_env(struct argv_array *out)
 	}
 	argv_array_push(out, "GIT_DIR=.git");
 }
+
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
+{
+	const struct submodule *sub;
+	const char *git_dir;
+	int ret = 0;
+
+	strbuf_reset(buf);
+	strbuf_addstr(buf, submodule);
+	strbuf_complete(buf, '/');
+	strbuf_addstr(buf, ".git");
+
+	git_dir = read_gitfile(buf->buf);
+	if (git_dir) {
+		strbuf_reset(buf);
+		strbuf_addstr(buf, git_dir);
+	}
+	if (!is_git_directory(buf->buf)) {
+		gitmodules_config();
+		sub = submodule_from_path(null_sha1, submodule);
+		if (!sub) {
+			ret = -1;
+			goto cleanup;
+		}
+		strbuf_reset(buf);
+		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
+	}
+
+cleanup:
+	return ret;
+}
diff --git a/submodule.h b/submodule.h
index 23d76682b..2728494ce 100644
--- a/submodule.h
+++ b/submodule.h
@@ -70,6 +70,7 @@ extern int push_unpushed_submodules(struct sha1_array *commits,
 				    int dry_run);
 void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
 int parallel_submodules(void);
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 /*
  * Prepare the "env_array" parameter of a "struct child_process" for executing
-- 
2.11.0.157.gd943d85

[PATCH v2 14/16] refs: move submodule code out of files-backend.c

[Nguyễn Thái Ngọc Duy]

files-backend is now initialized with a $GIT_DIR. Converting a submodule
path to where real submodule gitdir is located is done in get_ref_store().

The new code in init_submodule_ref_store() is basically a copy of
strbuf_git_path_submodule().

This gives a slight performance improvement for submodules since we
don't convert submodule path to gitdir at every backend call like
before. We pay that once at ref-store creation.

More cleanup in files_downcast() follows shortly. It's separate to keep
noises from this patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 18 +++++++++++++-----
 refs/files-backend.c | 26 ++++++++------------------
 refs/refs-internal.h |  6 +++---
 3 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/refs.c b/refs.c
index 25f657a6f..58ac9a2a8 100644
--- a/refs.c
+++ b/refs.c
@@ -9,6 +9,7 @@
 #include "refs/refs-internal.h"
 #include "object.h"
 #include "tag.h"
+#include "submodule.h"
 
 /*
  * List of all available backends
@@ -1419,9 +1420,9 @@ static void register_submodule_ref_store(struct ref_store *refs,
 
 /*
  * Create, record, and return a ref_store instance for the specified
- * submodule (or the main repository if submodule is NULL).
+ * gitdir (or the main repository if gitdir is NULL).
  */
-static struct ref_store *ref_store_init(const char *submodule)
+static struct ref_store *ref_store_init(const char *gitdir)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1430,7 +1431,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(submodule);
+	refs = be->init(gitdir);
 	return refs;
 }
 
@@ -1455,6 +1456,7 @@ struct ref_store *get_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
+	int ret;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
@@ -1465,8 +1467,14 @@ struct ref_store *get_ref_store(const char *submodule)
 		return refs;
 
 	strbuf_addstr(&submodule_sb, submodule);
-	if (is_nonbare_repository_dir(&submodule_sb))
-		refs = ref_store_init(submodule);
+	ret = is_nonbare_repository_dir(&submodule_sb);
+	strbuf_release(&submodule_sb);
+	if (!ret)
+		return refs;
+
+	ret = submodule_to_gitdir(&submodule_sb, submodule);
+	if (!ret)
+		refs = ref_store_init(submodule_sb.buf);
 	strbuf_release(&submodule_sb);
 
 	if (refs)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 74e31d041..e8946e638 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -917,13 +917,6 @@ struct packed_ref_cache {
 struct files_ref_store {
 	struct ref_store base;
 
-	/*
-	 * The name of the submodule represented by this object, or
-	 * NULL if it represents the main repository's reference
-	 * store:
-	 */
-	const char *submodule;
-
 	struct strbuf gitdir;
 	struct strbuf gitcommondir;
 
@@ -945,12 +938,9 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
 	va_end(vap);
-	if (refs->submodule)
-		strbuf_git_path_submodule(sb, refs->submodule,
-					  "%s", tmp.buf);
-	else if (is_per_worktree_ref(tmp.buf) ||
-		 (skip_prefix(tmp.buf, "logs/", &ref) &&
-		  is_per_worktree_ref(ref)))
+	if (is_per_worktree_ref(tmp.buf) ||
+	    (skip_prefix(tmp.buf, "logs/", &ref) &&
+	     is_per_worktree_ref(ref)))
 		strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
 	else
 		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
@@ -1005,7 +995,7 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *submodule)
+static struct ref_store *files_ref_store_create(const char *gitdir)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
@@ -1015,8 +1005,9 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 	strbuf_init(&refs->gitdir, 0);
 	strbuf_init(&refs->gitcommondir, 0);
 
-	if (submodule) {
-		refs->submodule = xstrdup(submodule);
+	if (gitdir) {
+		strbuf_addstr(&refs->gitdir, gitdir);
+		get_common_dir_noenv(&refs->gitcommondir, gitdir);
 	} else {
 		strbuf_addstr(&refs->gitdir, get_git_dir());
 		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
@@ -1032,8 +1023,7 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	if (refs->submodule)
-		die("BUG: %s called for a submodule", caller);
+	/* This function is to be deleted in the next patch */
 }
 
 /*
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 69d02b6ba..d7112770d 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -476,12 +476,12 @@ struct ref_store;
 /* refs backends */
 
 /*
- * Initialize the ref_store for the specified submodule, or for the
- * main repository if submodule == NULL. These functions should call
+ * Initialize the ref_store for the specified gitdir, or for the
+ * current repository if gitdir == NULL. These functions should call
  * base_ref_store_init() to initialize the shared part of the
  * ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *submodule);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
-- 
2.11.0.157.gd943d85

[PATCH v2 15/16] files-backend: remove submodule_allowed from files_downcast()

[Nguyễn Thái Ngọc Duy]

Since submodule or not is irrelevant to files-backend after the last
patch, remove the parameter from files_downcast() and kill
files_assert_main_repository().

PS. This implies that all ref operations are allowed for submodules. But
we may need to look more closely to see if that's really true...

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 70 ++++++++++++++++------------------------------------
 1 file changed, 21 insertions(+), 49 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index e8946e638..d9fc29d8d 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1017,24 +1017,13 @@ static struct ref_store *files_ref_store_create(const char *gitdir)
 }
 
 /*
- * Die if refs is for a submodule (i.e., not for the main repository).
- * caller is used in any necessary error messages.
- */
-static void files_assert_main_repository(struct files_ref_store *refs,
-					 const char *caller)
-{
-	/* This function is to be deleted in the next patch */
-}
-
-/*
  * Downcast ref_store to files_ref_store. Die if ref_store is not a
  * files_ref_store. If submodule_allowed is not true, then also die if
  * files_ref_store is for a submodule (i.e., not for the main
  * repository). caller is used in any necessary error messages.
  */
-static struct files_ref_store *files_downcast(
-		struct ref_store *ref_store, int submodule_allowed,
-		const char *caller)
+static struct files_ref_store *files_downcast(struct ref_store *ref_store,
+					      const char *caller)
 {
 	struct files_ref_store *refs;
 
@@ -1044,9 +1033,6 @@ static struct files_ref_store *files_downcast(
 
 	refs = (struct files_ref_store *)ref_store;
 
-	if (!submodule_allowed)
-		files_assert_main_repository(refs, caller);
-
 	return refs;
 }
 
@@ -1382,7 +1368,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "read_raw_ref");
+		files_downcast(ref_store, "read_raw_ref");
 	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
@@ -1575,7 +1561,6 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	int ret = TRANSACTION_GENERIC_ERROR;
 
 	assert(err);
-	files_assert_main_repository(refs, "lock_raw_ref");
 
 	*type = 0;
 
@@ -1799,7 +1784,7 @@ static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
 static int files_peel_ref(struct ref_store *ref_store,
 			  const char *refname, unsigned char *sha1)
 {
-	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
+	struct files_ref_store *refs = files_downcast(ref_store, "peel_ref");
 	int flag;
 	unsigned char base[20];
 
@@ -1908,7 +1893,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 		const char *prefix, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "ref_iterator_begin");
+		files_downcast(ref_store, "ref_iterator_begin");
 	struct ref_dir *loose_dir, *packed_dir;
 	struct ref_iterator *loose_iter, *packed_iter;
 	struct files_ref_iterator *iter;
@@ -2041,7 +2026,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	int attempts_remaining = 3;
 	int resolved;
 
-	files_assert_main_repository(refs, "lock_ref_sha1_basic");
 	assert(err);
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
@@ -2189,8 +2173,6 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	files_assert_main_repository(refs, "lock_packed_refs");
-
 	if (!timeout_configured) {
 		git_config_get_int("core.packedrefstimeout", &timeout_value);
 		timeout_configured = 1;
@@ -2230,8 +2212,6 @@ static int commit_packed_refs(struct files_ref_store *refs)
 	int save_errno = 0;
 	FILE *out;
 
-	files_assert_main_repository(refs, "commit_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 
@@ -2263,8 +2243,6 @@ static void rollback_packed_refs(struct files_ref_store *refs)
 	struct packed_ref_cache *packed_ref_cache =
 		get_packed_ref_cache(refs);
 
-	files_assert_main_repository(refs, "rollback_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 	rollback_lock_file(packed_ref_cache->lock);
@@ -2410,7 +2388,7 @@ static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "pack_refs");
+		files_downcast(ref_store, "pack_refs");
 	struct pack_refs_cb_data cbdata;
 
 	memset(&cbdata, 0, sizeof(cbdata));
@@ -2443,7 +2421,6 @@ static int repack_without_refs(struct files_ref_store *refs,
 	struct string_list_item *refname;
 	int ret, needs_repacking = 0, removed = 0;
 
-	files_assert_main_repository(refs, "repack_without_refs");
 	assert(err);
 
 	/* Look for a packed ref */
@@ -2511,7 +2488,7 @@ static int files_delete_refs(struct ref_store *ref_store,
 			     struct string_list *refnames, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_refs");
+		files_downcast(ref_store, "delete_refs");
 	struct strbuf err = STRBUF_INIT;
 	int i, result = 0;
 
@@ -2619,7 +2596,7 @@ static int files_verify_refname_available(struct ref_store *ref_store,
 					  struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "verify_refname_available");
+		files_downcast(ref_store, "verify_refname_available");
 	struct ref_dir *packed_refs = get_packed_refs(refs);
 	struct ref_dir *loose_refs = get_loose_refs(refs);
 
@@ -2644,7 +2621,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			    const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "rename_ref");
+		files_downcast(ref_store, "rename_ref");
 	unsigned char sha1[20], orig_sha1[20];
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
@@ -2866,7 +2843,7 @@ static int files_create_reflog(struct ref_store *ref_store,
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_reflog");
+		files_downcast(ref_store, "create_reflog");
 
 	ret = log_ref_setup(refs, refname, &sb, err, force_create);
 	strbuf_release(&sb);
@@ -3004,8 +2981,6 @@ static int commit_ref_update(struct files_ref_store *refs,
 			     const unsigned char *sha1, const char *logmsg,
 			     struct strbuf *err)
 {
-	files_assert_main_repository(refs, "commit_ref_update");
-
 	clear_loose_ref_cache(refs);
 	if (log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
 			  sha1, logmsg, 0, err)) {
@@ -3114,7 +3089,7 @@ static int files_create_symref(struct ref_store *ref_store,
 			       const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_symref");
+		files_downcast(ref_store, "create_symref");
 	struct strbuf err = STRBUF_INIT;
 	struct ref_lock *lock;
 	int ret;
@@ -3140,7 +3115,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
+		files_downcast(get_ref_store(NULL), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3178,7 +3153,7 @@ static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_exists");
+		files_downcast(ref_store, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
@@ -3193,7 +3168,7 @@ static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_reflog");
+		files_downcast(ref_store, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
@@ -3248,7 +3223,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
+		files_downcast(ref_store, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
@@ -3356,7 +3331,7 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent");
+		files_downcast(ref_store, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
@@ -3444,7 +3419,7 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_iterator_begin");
+		files_downcast(ref_store, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
@@ -3656,8 +3631,6 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 	int ret;
 	struct ref_lock *lock;
 
-	files_assert_main_repository(refs, "lock_ref_for_update");
-
 	if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
 		update->flags |= REF_DELETING;
 
@@ -3782,7 +3755,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 				    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "ref_transaction_commit");
+		files_downcast(ref_store, "ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
@@ -3956,7 +3929,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 					    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "initial_ref_transaction_commit");
+		files_downcast(ref_store, "initial_ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
@@ -4078,7 +4051,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			       void *policy_cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_expire");
+		files_downcast(ref_store, "reflog_expire");
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
@@ -4183,8 +4156,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "init_db");
+	struct files_ref_store *refs = files_downcast(ref_store, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
 	/*
-- 
2.11.0.157.gd943d85

[PATCH v2 16/16] refs: rename get_ref_store() to get_submodule_ref_store() and make it public

[Nguyễn Thái Ngọc Duy]

This function is intended to replace *_submodule() refs API. It provides
a ref store for a specific submodule, which can be operated on by a new
set of refs API.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 12 ++++++++----
 refs.h               | 11 +++++++++++
 refs/files-backend.c |  2 +-
 refs/refs-internal.h | 12 ------------
 4 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/refs.c b/refs.c
index 58ac9a2a8..e7206a420 100644
--- a/refs.c
+++ b/refs.c
@@ -1160,7 +1160,7 @@ int head_ref(each_ref_fn fn, void *cb_data)
 static int do_for_each_ref(const char *submodule, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(submodule);
+	struct ref_store *refs = get_submodule_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
@@ -1333,10 +1333,10 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
 		/* We need to strip off one or more trailing slashes */
 		char *stripped = xmemdupz(submodule, len);
 
-		refs = get_ref_store(stripped);
+		refs = get_submodule_ref_store(stripped);
 		free(stripped);
 	} else {
-		refs = get_ref_store(submodule);
+		refs = get_submodule_ref_store(submodule);
 	}
 
 	if (!refs)
@@ -1452,13 +1452,17 @@ struct ref_store *get_main_ref_store(void)
 	return refs;
 }
 
-struct ref_store *get_ref_store(const char *submodule)
+struct ref_store *get_submodule_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 	int ret;
 
 	if (!submodule || !*submodule) {
+		/*
+		 * FIXME: This case is ideally not allowed. But that
+		 * can't happen until we clean up all the callers.
+		 */
 		return get_main_ref_store();
 	}
 
diff --git a/refs.h b/refs.h
index f803528fc..1287ba59c 100644
--- a/refs.h
+++ b/refs.h
@@ -554,5 +554,16 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int ref_storage_backend_exists(const char *name);
 
 struct ref_store *get_main_ref_store(void);
+/*
+ * Return the ref_store instance for the specified submodule. For the
+ * main repository, use submodule==NULL; such a call cannot fail. For
+ * a submodule, the submodule must exist and be a nonbare repository,
+ * otherwise return NULL. If the requested reference store has not yet
+ * been initialized, initialize it first.
+ *
+ * For backwards compatibility, submodule=="" is treated the same as
+ * submodule==NULL.
+ */
+struct ref_store *get_submodule_ref_store(const char *submodule);
 
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index d9fc29d8d..685ea5c14 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3115,7 +3115,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), "set_head_symref");
+		files_downcast(get_main_ref_store(), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index d7112770d..cb6882779 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -634,18 +634,6 @@ struct ref_store {
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-/*
- * Return the ref_store instance for the specified submodule. For the
- * main repository, use submodule==NULL; such a call cannot fail. For
- * a submodule, the submodule must exist and be a nonbare repository,
- * otherwise return NULL. If the requested reference store has not yet
- * been initialized, initialize it first.
- *
- * For backwards compatibility, submodule=="" is treated the same as
- * submodule==NULL.
- */
-struct ref_store *get_ref_store(const char *submodule);
-
 const char *resolve_ref_recursively(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
-- 
2.11.0.157.gd943d85

Re: [PATCH v2 00/16] Remove submodule from files-backend.c

[Stefan Beller]

This series looks good to me.

Thanks,
Stefan

[PATCH v3 00/16] Remove submodule from files-backend.c

[Nguyễn Thái Ngọc Duy]

v3 only changes 07/16 but it's kinda important because I broke
packed-refs. packed-refs' path became $GIT_DIR/packed-refs instead of
$GIT_COMMON_DIR/packed-refs and as a result the majority of refs will
disappear in linked worktrees. Interdiff

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 685ea5c14..82be3f90f 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -938,9 +938,11 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
 	va_end(vap);
-	if (is_per_worktree_ref(tmp.buf) ||
-	    (skip_prefix(tmp.buf, "logs/", &ref) &&
-	     is_per_worktree_ref(ref)))
+	if (!strcmp(tmp.buf, "packed-refs") || !strcmp(tmp.buf, "logs"))
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
+	else if (is_per_worktree_ref(tmp.buf) ||
+		 (skip_prefix(tmp.buf, "logs/", &ref) &&
+		  is_per_worktree_ref(ref)))
 		strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
 	else
 		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);

Nguyễn Thái Ngọc Duy (16):
  refs-internal.c: make files_log_ref_write() static
  files-backend: convert git_path() to strbuf_git_path()
  files-backend: add files_path()
  files-backend: replace *git_path*() with files_path()
  refs.c: share is_per_worktree_ref() to files-backend.c
  refs-internal.h: correct is_per_worktree_ref()
  files-backend: remove the use of git_path()
  refs.c: introduce get_main_ref_store()
  refs: rename lookup_ref_store() to lookup_submodule_ref_store()
  refs.c: flatten get_ref_store() a bit
  refs.c: kill register_ref_store(), add register_submodule_ref_store()
  refs.c: make get_main_ref_store() public and use it
  path.c: move some code out of strbuf_git_path_submodule()
  refs: move submodule code out of files-backend.c
  files-backend: remove submodule_allowed from files_downcast()
  refs: rename get_ref_store() to get_submodule_ref_store() and make it public

 path.c               |  34 ++---
 refs.c               | 144 +++++++++++----------
 refs.h               |  13 ++
 refs/files-backend.c | 349 +++++++++++++++++++++++++++++++--------------------
 refs/refs-internal.h |  28 ++---
 submodule.c          |  31 +++++
 submodule.h          |   1 +
 7 files changed, 348 insertions(+), 252 deletions(-)

-- 
2.11.0.157.gd943d85

[PATCH v3 01/16] refs-internal.c: make files_log_ref_write() static

[Nguyễn Thái Ngọc Duy]

Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
but probably never used outside refs-internal.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 3 +++
 refs/refs-internal.h | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index cdb6b8ff5..75565c3aa 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+			       const unsigned char *new_sha1, const char *msg,
+			       int flags, struct strbuf *err);
 
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 33adbf93b..59e65958a 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -222,10 +222,6 @@ struct ref_transaction {
 	enum ref_transaction_state state;
 };
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err);
-
 /*
  * Check for entries in extras that are within the specified
  * directory, where dirname is a reference directory name including
-- 
2.11.0.157.gd943d85

[PATCH v3 02/16] files-backend: convert git_path() to strbuf_git_path()

[Nguyễn Thái Ngọc Duy]

git_path() and friends are going to be killed in files-backend.c in near
future. And because there's a risk with overwriting buffer in
git_path(), let's convert them all to strbuf_git_path(). We'll have
easier time killing/converting strbuf_git_path() then because we won't
have to worry about memory management again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 111 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 89 insertions(+), 22 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 75565c3aa..f0c878b92 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2169,6 +2169,8 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	static int timeout_configured = 0;
 	static int timeout_value = 1000;
 	struct packed_ref_cache *packed_ref_cache;
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
 
 	files_assert_main_repository(refs, "lock_packed_refs");
 
@@ -2177,10 +2179,13 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	if (hold_lock_file_for_update_timeout(
-			    &packlock, git_path("packed-refs"),
-			    flags, timeout_value) < 0)
+	strbuf_git_path(&sb, "packed-refs");
+	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
+						flags, timeout_value);
+	strbuf_release(&sb);
+	if (ret < 0)
 		return -1;
+
 	/*
 	 * Get the current packed-refs while holding the lock.  If the
 	 * packed-refs file has been modified since we last read it,
@@ -2335,6 +2340,9 @@ static void try_remove_empty_parents(char *name)
 	for (q = p; *q; q++)
 		;
 	while (1) {
+		struct strbuf sb = STRBUF_INIT;
+		int ret;
+
 		while (q > p && *q != '/')
 			q--;
 		while (q > p && *(q-1) == '/')
@@ -2342,7 +2350,10 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		if (rmdir(git_path("%s", name)))
+		strbuf_git_path(&sb, "%s", name);
+		ret = rmdir(sb.buf);
+		strbuf_release(&sb);
+		if (ret)
 			break;
 	}
 }
@@ -2431,7 +2442,11 @@ static int repack_without_refs(struct files_ref_store *refs,
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(refs, 0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "packed-refs");
+		unable_to_lock_message(sb.buf, errno, err);
+		strbuf_release(&sb);
 		return -1;
 	}
 	packed = get_packed_refs(refs);
@@ -2529,8 +2544,10 @@ static int rename_tmp_log(const char *newrefname)
 {
 	int attempts_remaining = 4;
 	struct strbuf path = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
 	int ret = -1;
 
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
  retry:
 	strbuf_reset(&path);
 	strbuf_git_path(&path, "logs/%s", newrefname);
@@ -2546,7 +2563,7 @@ static int rename_tmp_log(const char *newrefname)
 		goto out;
 	}
 
-	if (rename(git_path(TMP_RENAMED_LOG), path.buf)) {
+	if (rename(tmp_renamed_log.buf, path.buf)) {
 		if ((errno==EISDIR || errno==ENOTDIR) && --attempts_remaining > 0) {
 			/*
 			 * rename(a, b) when b is an existing
@@ -2574,6 +2591,7 @@ static int rename_tmp_log(const char *newrefname)
 	ret = 0;
 out:
 	strbuf_release(&path);
+	strbuf_release(&tmp_renamed_log);
 	return ret;
 }
 
@@ -2614,9 +2632,15 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
-	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+	struct strbuf sb_oldref = STRBUF_INIT;
+	struct strbuf sb_newref = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
+	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	log = !lstat(sb_oldref.buf, &loginfo);
+	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2630,7 +2654,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
+	if (ret)
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
@@ -2709,13 +2738,19 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
+	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
+	strbuf_release(&sb_newref);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
 
 	return 1;
 }
@@ -3111,22 +3146,32 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
+	int ret;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_exists");
 
-	return !lstat(git_path("logs/%s", refname), &st) &&
-		S_ISREG(st.st_mode);
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "delete_reflog");
 
-	return remove_path(git_path("logs/%s", refname));
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = remove_path(sb.buf);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
@@ -3181,7 +3226,9 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3287,7 +3334,9 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3369,12 +3418,15 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 {
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
+	struct strbuf sb = STRBUF_INIT;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_iterator_begin");
 
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	iter->dir_iterator = dir_iterator_begin(git_path("logs"));
+	strbuf_git_path(&sb, "logs");
+	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	strbuf_release(&sb);
 	return ref_iterator;
 }
 
@@ -3843,8 +3895,13 @@ static int files_transaction_commit(struct ref_store *ref_store,
 		ret = TRANSACTION_GENERIC_ERROR;
 		goto cleanup;
 	}
-	for_each_string_list_item(ref_to_delete, &refs_to_delete)
-		unlink_or_warn(git_path("logs/%s", ref_to_delete->string));
+	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		unlink_or_warn(sb.buf);
+		strbuf_release(&sb);
+	}
 	clear_loose_ref_cache(refs);
 
 cleanup:
@@ -4098,18 +4155,28 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct strbuf sb = STRBUF_INIT;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "init_db");
 
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	strbuf_git_path(&sb, "refs/heads");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
+	strbuf_git_path(&sb, "refs/tags");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		strbuf_git_path(&sb, "refs/heads");
+		adjust_shared_perm(sb.buf);
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "refs/tags");
+		adjust_shared_perm(sb.buf);
 	}
+	strbuf_release(&sb);
 	return 0;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v3 03/16] files-backend: add files_path()

[Nguyễn Thái Ngọc Duy]

This will be the replacement for both git_path() and git_path_submodule()
in this file. The idea is backend takes a git path and use that,
oblivious of submodule, linked worktrees and such.

This is the middle step towards that. Eventually the "submodule" field
in 'struct files_ref_store' should be replace by "gitdir". And a
compound ref_store is created to combine two files backends together,
one represents the shared refs in $GIT_COMMON_DIR, one per-worktree. At
that point, files_path() becomes a wrapper of strbuf_vaddf().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index f0c878b92..abb8a95e0 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -930,6 +930,24 @@ struct files_ref_store {
 /* Lock used for the main packed-refs file: */
 static struct lock_file packlock;
 
+__attribute__((format (printf, 3, 4)))
+static void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		       const char *fmt, ...)
+{
+	struct strbuf tmp = STRBUF_INIT;
+	va_list vap;
+
+	va_start(vap, fmt);
+	strbuf_vaddf(&tmp, fmt, vap);
+	va_end(vap);
+	if (refs->submodule)
+		strbuf_git_path_submodule(sb, refs->submodule,
+					  "%s", tmp.buf);
+	else
+		strbuf_git_path(sb, "%s", tmp.buf);
+	strbuf_release(&tmp);
+}
+
 /*
  * Increment the reference count of *packed_refs.
  */
-- 
2.11.0.157.gd943d85

Re: [PATCH v3 03/16] files-backend: add files_path()

[Junio C Hamano]

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> This will be the replacement for both git_path() and git_path_submodule()
> in this file. The idea is backend takes a git path and use that,
> oblivious of submodule, linked worktrees and such.
>
> This is the middle step towards that. Eventually the "submodule" field
> in 'struct files_ref_store' should be replace by "gitdir". And a

s/replace/&d/;

> compound ref_store is created to combine two files backends together,
> one represents the shared refs in $GIT_COMMON_DIR, one per-worktree. At
> that point, files_path() becomes a wrapper of strbuf_vaddf().

I like the general direction, obviously ;-)

>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index f0c878b92..abb8a95e0 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -930,6 +930,24 @@ struct files_ref_store {
>  /* Lock used for the main packed-refs file: */
>  static struct lock_file packlock;
>  
> +__attribute__((format (printf, 3, 4)))
> +static void files_path(struct files_ref_store *refs, struct strbuf *sb,
> +		       const char *fmt, ...)
> +{
> +	struct strbuf tmp = STRBUF_INIT;
> +	va_list vap;
> +
> +	va_start(vap, fmt);
> +	strbuf_vaddf(&tmp, fmt, vap);
> +	va_end(vap);
> +	if (refs->submodule)
> +		strbuf_git_path_submodule(sb, refs->submodule,
> +					  "%s", tmp.buf);
> +	else
> +		strbuf_git_path(sb, "%s", tmp.buf);
> +	strbuf_release(&tmp);
> +}
> +
>  /*
>   * Increment the reference count of *packed_refs.
>   */

[PATCH v3 04/16] files-backend: replace *git_path*() with files_path()

[Nguyễn Thái Ngọc Duy]

This centralizes all path rewriting of files-backend.c in one place so
we have easier time removing the path rewriting later. There could be
some hidden indirect git_path() though, I didn't audit the code to the
bottom.

Side note: set_worktree_head_symref() is a bad boy and should not be in
files-backend.c (probably should not exist in the first place). But
we'll leave it there until we have better multi-worktree support in refs
before we update it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 185 ++++++++++++++++++++++++++-------------------------
 1 file changed, 94 insertions(+), 91 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index abb8a95e0..24f5bf7f1 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,7 +165,8 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
-static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int files_log_ref_write(struct files_ref_store *refs,
+			       const char *refname, const unsigned char *old_sha1,
 			       const unsigned char *new_sha1, const char *msg,
 			       int flags, struct strbuf *err);
 
@@ -1178,12 +1179,10 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
 {
 	char *packed_refs_file;
+	struct strbuf sb = STRBUF_INIT;
 
-	if (refs->submodule)
-		packed_refs_file = git_pathdup_submodule(refs->submodule,
-							 "packed-refs");
-	else
-		packed_refs_file = git_pathdup("packed-refs");
+	files_path(refs, &sb, "packed-refs");
+	packed_refs_file = strbuf_detach(&sb, NULL);
 
 	if (refs->packed &&
 	    !stat_validity_check(&refs->packed->validity, packed_refs_file))
@@ -1249,10 +1248,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 	size_t path_baselen;
 	int err = 0;
 
-	if (refs->submodule)
-		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
-	else
-		strbuf_git_path(&path, "%s", dirname);
+	files_path(refs, &path, "%s", dirname);
 	path_baselen = path.len;
 
 	if (err) {
@@ -1394,10 +1390,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	*type = 0;
 	strbuf_reset(&sb_path);
 
-	if (refs->submodule)
-		strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
-	else
-		strbuf_git_path(&sb_path, "%s", refname);
+	files_path(refs, &sb_path, "%s", refname);
 
 	path = sb_path.buf;
 
@@ -1585,7 +1578,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	*lock_p = lock = xcalloc(1, sizeof(*lock));
 
 	lock->ref_name = xstrdup(refname);
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 
 retry:
 	switch (safe_create_leading_directories(ref_file.buf)) {
@@ -2052,7 +2045,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	if (flags & REF_DELETING)
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
 					lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
@@ -2197,7 +2190,7 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	strbuf_git_path(&sb, "packed-refs");
+	files_path(refs, &sb, "packed-refs");
 	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
 						flags, timeout_value);
 	strbuf_release(&sb);
@@ -2343,7 +2336,7 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
  * Remove empty parents, but spare refs/ and immediate subdirs.
  * Note: munges *name.
  */
-static void try_remove_empty_parents(char *name)
+static void try_remove_empty_parents(struct files_ref_store *refs, char *name)
 {
 	char *p, *q;
 	int i;
@@ -2368,7 +2361,7 @@ static void try_remove_empty_parents(char *name)
 		if (q == p)
 			break;
 		*q = '\0';
-		strbuf_git_path(&sb, "%s", name);
+		files_path(refs, &sb, "%s", name);
 		ret = rmdir(sb.buf);
 		strbuf_release(&sb);
 		if (ret)
@@ -2377,7 +2370,7 @@ static void try_remove_empty_parents(char *name)
 }
 
 /* make sure nobody touched the ref, and unlink */
-static void prune_ref(struct ref_to_prune *r)
+static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -2397,13 +2390,13 @@ static void prune_ref(struct ref_to_prune *r)
 	}
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
-	try_remove_empty_parents(r->name);
+	try_remove_empty_parents(refs, r->name);
 }
 
-static void prune_refs(struct ref_to_prune *r)
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	while (r) {
-		prune_ref(r);
+		prune_ref(refs, r);
 		r = r->next;
 	}
 }
@@ -2426,7 +2419,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 	if (commit_packed_refs(refs))
 		die_errno("unable to overwrite old ref-pack file");
 
-	prune_refs(cbdata.ref_to_prune);
+	prune_refs(refs, cbdata.ref_to_prune);
 	return 0;
 }
 
@@ -2462,7 +2455,7 @@ static int repack_without_refs(struct files_ref_store *refs,
 	if (lock_packed_refs(refs, 0)) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "packed-refs");
+		files_path(refs, &sb, "packed-refs");
 		unable_to_lock_message(sb.buf, errno, err);
 		strbuf_release(&sb);
 		return -1;
@@ -2558,17 +2551,17 @@ static int files_delete_refs(struct ref_store *ref_store,
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 {
 	int attempts_remaining = 4;
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf tmp_renamed_log = STRBUF_INIT;
 	int ret = -1;
 
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
  retry:
 	strbuf_reset(&path);
-	strbuf_git_path(&path, "logs/%s", newrefname);
+	files_path(refs, &path, "logs/%s", newrefname);
 	switch (safe_create_leading_directories_const(path.buf)) {
 	case SCLD_OK:
 		break; /* success */
@@ -2656,7 +2649,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	log = !lstat(sb_oldref.buf, &loginfo);
 	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
@@ -2672,8 +2665,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
 	strbuf_release(&sb_oldref);
 	strbuf_release(&tmp_renamed_log);
@@ -2700,7 +2693,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			struct strbuf path = STRBUF_INIT;
 			int result;
 
-			strbuf_git_path(&path, "%s", newrefname);
+			files_path(refs, &path, "%s", newrefname);
 			result = remove_empty_directories(&path);
 			strbuf_release(&path);
 
@@ -2714,7 +2707,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 		}
 	}
 
-	if (log && rename_tmp_log(newrefname))
+	if (log && rename_tmp_log(refs, newrefname))
 		goto rollback;
 
 	logmoved = log;
@@ -2756,12 +2749,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_newref, "logs/%s", newrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
 	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
@@ -2817,11 +2810,13 @@ static int commit_ref(struct ref_lock *lock)
  * should_autocreate_reflog returns non-zero.  Otherwise, create it
  * regardless of the ref name.  Fill in *err and return -1 on failure.
  */
-static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
+static int log_ref_setup(struct files_ref_store *refs, const char *refname,
+			 struct strbuf *logfile, struct strbuf *err,
+			 int force_create)
 {
 	int logfd, oflags = O_APPEND | O_WRONLY;
 
-	strbuf_git_path(logfile, "logs/%s", refname);
+	files_path(refs, logfile, "logs/%s", refname);
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (safe_create_leading_directories(logfile->buf) < 0) {
 			strbuf_addf(err, "unable to create directory for '%s': "
@@ -2864,11 +2859,10 @@ static int files_create_reflog(struct ref_store *ref_store,
 {
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "create_reflog");
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "create_reflog");
-
-	ret = log_ref_setup(refname, &sb, err, force_create);
+	ret = log_ref_setup(refs, refname, &sb, err, force_create);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -2899,7 +2893,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
+static int log_ref_write_1(struct files_ref_store *refs,
+			   const char *refname, const unsigned char *old_sha1,
 			   const unsigned char *new_sha1, const char *msg,
 			   struct strbuf *logfile, int flags,
 			   struct strbuf *err)
@@ -2909,7 +2904,7 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	if (log_all_ref_updates < 0)
 		log_all_ref_updates = !is_bare_repository();
 
-	result = log_ref_setup(refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
+	result = log_ref_setup(refs, refname, logfile, err, flags & REF_FORCE_CREATE_REFLOG);
 
 	if (result)
 		return result;
@@ -2933,21 +2928,23 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
 	return 0;
 }
 
-static int log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int log_ref_write(struct files_ref_store *refs,
+			 const char *refname, const unsigned char *old_sha1,
 			 const unsigned char *new_sha1, const char *msg,
 			 int flags, struct strbuf *err)
 {
-	return files_log_ref_write(refname, old_sha1, new_sha1, msg, flags,
-				   err);
+	return files_log_ref_write(refs, refname, old_sha1, new_sha1,
+				   msg, flags, err);
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+int files_log_ref_write(struct files_ref_store *refs,
+			const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)
 {
 	struct strbuf sb = STRBUF_INIT;
-	int ret = log_ref_write_1(refname, old_sha1, new_sha1, msg, &sb, flags,
-				  err);
+	int ret = log_ref_write_1(refs, refname, old_sha1, new_sha1, msg,
+				  &sb, flags, err);
 	strbuf_release(&sb);
 	return ret;
 }
@@ -3004,7 +3001,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (log_ref_write(lock->ref_name, lock->old_oid.hash, sha1, logmsg, 0, err)) {
+	if (log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
+			  sha1, logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
 			    lock->ref_name, old_msg);
@@ -3035,8 +3033,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (log_ref_write("HEAD", lock->old_oid.hash, sha1,
-					  logmsg, 0, &log_err)) {
+			if (log_ref_write(refs, "HEAD", lock->old_oid.hash,
+					  sha1, logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
 			}
@@ -3068,23 +3066,26 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 	return ret;
 }
 
-static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+static void update_symref_reflog(struct files_ref_store *refs,
+				 struct ref_lock *lock, const char *refname,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
 	if (logmsg && !read_ref(target, new_sha1) &&
-	    log_ref_write(refname, lock->old_oid.hash, new_sha1, logmsg, 0, &err)) {
+	    log_ref_write(refs, refname, lock->old_oid.hash,
+			  new_sha1, logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
 }
 
-static int create_symref_locked(struct ref_lock *lock, const char *refname,
+static int create_symref_locked(struct files_ref_store *refs,
+				struct ref_lock *lock, const char *refname,
 				const char *target, const char *logmsg)
 {
 	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(lock, refname, target, logmsg);
+		update_symref_reflog(refs, lock, refname, target, logmsg);
 		return 0;
 	}
 
@@ -3092,7 +3093,7 @@ static int create_symref_locked(struct ref_lock *lock, const char *refname,
 		return error("unable to fdopen %s: %s",
 			     lock->lk->tempfile.filename.buf, strerror(errno));
 
-	update_symref_reflog(lock, refname, target, logmsg);
+	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
 	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
@@ -3121,13 +3122,19 @@ static int files_create_symref(struct ref_store *ref_store,
 		return -1;
 	}
 
-	ret = create_symref_locked(lock, refname, target, logmsg);
+	ret = create_symref_locked(refs, lock, refname, target, logmsg);
 	unlock_ref(lock);
 	return ret;
 }
 
 int set_worktree_head_symref(const char *gitdir, const char *target)
 {
+	/*
+	 * FIXME: this obviously will not work well for future refs
+	 * backends. This function needs to die.
+	 */
+	struct files_ref_store *refs =
+		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3154,7 +3161,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	lock->lk = &head_lock;
 	lock->ref_name = xstrdup(head_rel);
 
-	ret = create_symref_locked(lock, head_rel, target, NULL);
+	ret = create_symref_locked(refs, lock, head_rel, target, NULL);
 
 	unlock_ref(lock); /* will free lock */
 	strbuf_release(&head_path);
@@ -3164,14 +3171,13 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_exists");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
 	strbuf_release(&sb);
 	return ret;
@@ -3180,13 +3186,12 @@ static int files_reflog_exists(struct ref_store *ref_store,
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "delete_reflog");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = remove_path(sb.buf);
 	strbuf_release(&sb);
 	return ret;
@@ -3236,15 +3241,14 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     each_reflog_ent_fn fn,
 					     void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
 	int ret = 0, at_tail = 1;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3345,14 +3349,13 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     const char *refname,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3434,15 +3437,14 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_iterator_begin");
-
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	strbuf_git_path(&sb, "logs");
+	files_path(refs, &sb, "logs");
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
 	strbuf_release(&sb);
 	return ref_iterator;
@@ -3866,8 +3868,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (log_ref_write(lock->ref_name, lock->old_oid.hash,
-					  update->new_sha1,
+			if (log_ref_write(refs, lock->ref_name,
+					  lock->old_oid.hash, update->new_sha1,
 					  update->msg, update->flags, err)) {
 				char *old_msg = strbuf_detach(err, NULL);
 
@@ -3916,7 +3918,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		files_path(refs, &sb, "logs/%s", ref_to_delete->string);
 		unlink_or_warn(sb.buf);
 		strbuf_release(&sb);
 	}
@@ -4078,6 +4080,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	int status = 0;
 	int type;
 	struct strbuf err = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 
 	memset(&cb, 0, sizeof(cb));
 	cb.flags = flags;
@@ -4102,7 +4105,8 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		return 0;
 	}
 
-	log_file = git_pathdup("logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
+	log_file = strbuf_detach(&sb, NULL);
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 		/*
 		 * Even though holding $GIT_DIR/logs/$reflog.lock has
@@ -4173,25 +4177,24 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "init_db");
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	strbuf_git_path(&sb, "refs/heads");
+	files_path(refs, &sb, "refs/heads");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
-	strbuf_git_path(&sb, "refs/tags");
+	files_path(refs, &sb, "refs/tags");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		strbuf_git_path(&sb, "refs/heads");
+		files_path(refs, &sb, "refs/heads");
 		adjust_shared_perm(sb.buf);
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "refs/tags");
+		files_path(refs, &sb, "refs/tags");
 		adjust_shared_perm(sb.buf);
 	}
 	strbuf_release(&sb);
-- 
2.11.0.157.gd943d85

Re: [PATCH v3 04/16] files-backend: replace *git_path*() with files_path()

[Junio C Hamano]

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> This centralizes all path rewriting of files-backend.c in one place so
> we have easier time removing the path rewriting later. There could be
> some hidden indirect git_path() though, I didn't audit the code to the
> bottom.
>
> Side note: set_worktree_head_symref() is a bad boy and should not be in
> files-backend.c (probably should not exist in the first place). But
> we'll leave it there until we have better multi-worktree support in refs
> before we update it.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 185 ++++++++++++++++++++++++++-------------------------
>  1 file changed, 94 insertions(+), 91 deletions(-)

In this step, files_path() is still "if refs->submodule field is
there, then use that to call strbuf_git_path_submodule() and
otherwise call strbuf_git_path()."  That is a very sensible
refactoring for things like packed-refs-file in this hunk:

>  static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
>  {
>  	char *packed_refs_file;
> +	struct strbuf sb = STRBUF_INIT;
>  
> -	if (refs->submodule)
> -		packed_refs_file = git_pathdup_submodule(refs->submodule,
> -							 "packed-refs");
> -	else
> -		packed_refs_file = git_pathdup("packed-refs");
> +	files_path(refs, &sb, "packed-refs");
> +	packed_refs_file = strbuf_detach(&sb, NULL);

But the original code of some other changes do not follow that
pattern, e.g.

> @@ -1585,7 +1578,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
>  	*lock_p = lock = xcalloc(1, sizeof(*lock));
>  
>  	lock->ref_name = xstrdup(refname);
> -	strbuf_git_path(&ref_file, "%s", refname);
> +	files_path(refs, &ref_file, "%s", refname);

Is it the right way to review these changes to make sure that a
conversion from the original that is an unconditional
strbuf_git_path() to files_path() happens only if the function is
"files-assert-main-repository" clean?  lock_raw_ref() certainly is
one of those functions where the caller should not have a non-empty
submodule field in refs.

> @@ -2052,7 +2045,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
>  	if (flags & REF_DELETING)
>  		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
>  
> -	strbuf_git_path(&ref_file, "%s", refname);
> +	files_path(refs, &ref_file, "%s", refname);

So is this one; lock_ref_sha1_basic() is protected with assert-main-repo.

> @@ -2343,7 +2336,7 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
>   * Remove empty parents, but spare refs/ and immediate subdirs.
>   * Note: munges *name.
>   */
> -static void try_remove_empty_parents(char *name)
> +static void try_remove_empty_parents(struct files_ref_store *refs, char *name)
>  {
>  	char *p, *q;
>  	int i;
> @@ -2368,7 +2361,7 @@ static void try_remove_empty_parents(char *name)
>  		if (q == p)
>  			break;
>  		*q = '\0';
> -		strbuf_git_path(&sb, "%s", name);
> +		files_path(refs, &sb, "%s", name);

But here it gets iffy.  try_remove_empty_parents() itself does not
assert, and its sole caller prune_ref() does not, either.  The sole
caller of prune_ref() which is prune_refs() does not.  As we climb
the call chain up, we reach files_pack_refs().  Am I confused to
doubt that the method is inherently main-repo only?

    ... ah, OK, files_downcast() at the beginning of pack_refs
    forbids submodule.  So this is safe.


> @@ -2462,7 +2455,7 @@ static int repack_without_refs(struct files_ref_store *refs,
>  	if (lock_packed_refs(refs, 0)) {
>  		struct strbuf sb = STRBUF_INIT;
>  
> -		strbuf_git_path(&sb, "packed-refs");
> +		files_path(refs, &sb, "packed-refs");

This is safe, as repack_without_refs() asserts that it is main-repo
only.

> @@ -2558,17 +2551,17 @@ static int files_delete_refs(struct ref_store *ref_store,
>   */
>  #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
>  
> -static int rename_tmp_log(const char *newrefname)
> +static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
>  {

The sole caller files_rename_ref() is main-repo only and that is
guaranteed when downcast is done.

> -static int log_ref_setup(const char *refname, struct strbuf *logfile, struct strbuf *err, int force_create)
> +static int log_ref_setup(struct files_ref_store *refs, const char *refname,
> +			 struct strbuf *logfile, struct strbuf *err,
> +			 int force_create)
>  {
>  	int logfd, oflags = O_APPEND | O_WRONLY;
>  
> -	strbuf_git_path(logfile, "logs/%s", refname);
> +	files_path(refs, logfile, "logs/%s", refname);

This and friends of log_ref_write() eventually rolls up to
commit_ref_update() that has the main-repo only assertion, so they
should be safe.

Another entry point files_create_symref() via create_symref_locked()
also reaches log_ref_write() and friends but the safety is guaranteed
via the downcast that asserts.

OK, overall I really like the loss of "Check the validity but we do
not need the result" with this step.  The same checks are still done
but the code looks much less hacky.

[PATCH v3 05/16] refs.c: share is_per_worktree_ref() to files-backend.c

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 6 ------
 refs/refs-internal.h | 6 ++++++
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/refs.c b/refs.c
index 4f845798b..7a474198e 100644
--- a/refs.c
+++ b/refs.c
@@ -489,12 +489,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-static int is_per_worktree_ref(const char *refname)
-{
-	return !strcmp(refname, "HEAD") ||
-		starts_with(refname, "refs/bisect/");
-}
-
 static int is_pseudoref_syntax(const char *refname)
 {
 	const char *c;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 59e65958a..f4aed49f5 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -651,4 +651,10 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 				    int resolve_flags,
 				    unsigned char *sha1, int *flags);
 
+static inline int is_per_worktree_ref(const char *refname)
+{
+	return !strcmp(refname, "HEAD") ||
+		starts_with(refname, "refs/bisect/");
+}
+
 #endif /* REFS_REFS_INTERNAL_H */
-- 
2.11.0.157.gd943d85

[PATCH v3 06/16] refs-internal.h: correct is_per_worktree_ref()

[Nguyễn Thái Ngọc Duy]

All refs outside refs/ directory is per-worktree, not just HEAD.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/refs-internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index f4aed49f5..69d02b6ba 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -653,7 +653,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 
 static inline int is_per_worktree_ref(const char *refname)
 {
-	return !strcmp(refname, "HEAD") ||
+	return !starts_with(refname, "refs/") ||
 		starts_with(refname, "refs/bisect/");
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v3 07/16] files-backend: remove the use of git_path()

[Nguyễn Thái Ngọc Duy]

Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
deciding what goes where. The end goal is to pass $GIT_DIR only. A
refs "view" of a linked worktree is a logical ref store that combines
two files backends together.

(*) Not entirely true since strbuf_git_path_submodule() still does path
translation underneath. But that's for another patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 24f5bf7f1..07cf2cb93 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -924,6 +924,9 @@ struct files_ref_store {
 	 */
 	const char *submodule;
 
+	struct strbuf gitdir;
+	struct strbuf gitcommondir;
+
 	struct ref_entry *loose;
 	struct packed_ref_cache *packed;
 };
@@ -937,6 +940,7 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 {
 	struct strbuf tmp = STRBUF_INIT;
 	va_list vap;
+	const char *ref;
 
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
@@ -944,8 +948,14 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	if (refs->submodule)
 		strbuf_git_path_submodule(sb, refs->submodule,
 					  "%s", tmp.buf);
+	else if (!strcmp(tmp.buf, "packed-refs") || !strcmp(tmp.buf, "logs"))
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
+	else if (is_per_worktree_ref(tmp.buf) ||
+		 (skip_prefix(tmp.buf, "logs/", &ref) &&
+		  is_per_worktree_ref(ref)))
+		strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
 	else
-		strbuf_git_path(sb, "%s", tmp.buf);
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
 	strbuf_release(&tmp);
 }
 
@@ -1004,7 +1014,15 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
-	refs->submodule = xstrdup_or_null(submodule);
+	strbuf_init(&refs->gitdir, 0);
+	strbuf_init(&refs->gitcommondir, 0);
+
+	if (submodule) {
+		refs->submodule = xstrdup(submodule);
+	} else {
+		strbuf_addstr(&refs->gitdir, get_git_dir());
+		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
+	}
 
 	return ref_store;
 }
-- 
2.11.0.157.gd943d85

[PATCH v3 08/16] refs.c: introduce get_main_ref_store()

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/refs.c b/refs.c
index 7a474198e..10994d992 100644
--- a/refs.c
+++ b/refs.c
@@ -1445,15 +1445,23 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
+static struct ref_store *get_main_ref_store(void)
+{
+	struct ref_store *refs;
+
+	if (main_ref_store)
+		return main_ref_store;
+
+	refs = ref_store_init(NULL);
+	return refs;
+}
+
 struct ref_store *get_ref_store(const char *submodule)
 {
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
-		refs = lookup_ref_store(NULL);
-
-		if (!refs)
-			refs = ref_store_init(NULL);
+		return get_main_ref_store();
 	} else {
 		refs = lookup_ref_store(submodule);
 
-- 
2.11.0.157.gd943d85

[PATCH v3 09/16] refs: rename lookup_ref_store() to lookup_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

With get_main_ref_store() being used inside get_ref_store(),
lookup_ref_store() is only used for submodule code path. Rename to
reflect that and delete dead code.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index 10994d992..ea13a5b86 100644
--- a/refs.c
+++ b/refs.c
@@ -1384,17 +1384,13 @@ static struct ref_store *main_ref_store;
 static struct hashmap submodule_ref_stores;
 
 /*
- * Return the ref_store instance for the specified submodule (or the
- * main repository if submodule is NULL). If that ref_store hasn't
- * been initialized yet, return NULL.
+ * Return the ref_store instance for the specified submodule. If that
+ * ref_store hasn't been initialized yet, return NULL.
  */
-static struct ref_store *lookup_ref_store(const char *submodule)
+static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 {
 	struct submodule_hash_entry *entry;
 
-	if (!submodule)
-		return main_ref_store;
-
 	if (!submodule_ref_stores.tablesize)
 		/* It's initialized on demand in register_ref_store(). */
 		return NULL;
@@ -1463,7 +1459,7 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
 	} else {
-		refs = lookup_ref_store(submodule);
+		refs = lookup_submodule_ref_store(submodule);
 
 		if (!refs) {
 			struct strbuf submodule_sb = STRBUF_INIT;
@@ -1474,7 +1470,6 @@ struct ref_store *get_ref_store(const char *submodule)
 			strbuf_release(&submodule_sb);
 		}
 	}
-
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v3 10/16] refs.c: flatten get_ref_store() a bit

[Nguyễn Thái Ngọc Duy]

This helps the future changes in this code. And because get_ref_store()
is destined to become get_submodule_ref_store(), the "get main store"
code path will be removed eventually. After this the patch to delete
that code will be cleaner.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/refs.c b/refs.c
index ea13a5b86..76a0e7b5a 100644
--- a/refs.c
+++ b/refs.c
@@ -1454,22 +1454,21 @@ static struct ref_store *get_main_ref_store(void)
 
 struct ref_store *get_ref_store(const char *submodule)
 {
+	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
-	} else {
-		refs = lookup_submodule_ref_store(submodule);
+	}
 
-		if (!refs) {
-			struct strbuf submodule_sb = STRBUF_INIT;
+	refs = lookup_submodule_ref_store(submodule);
+	if (refs)
+		return refs;
 
-			strbuf_addstr(&submodule_sb, submodule);
-			if (is_nonbare_repository_dir(&submodule_sb))
-				refs = ref_store_init(submodule);
-			strbuf_release(&submodule_sb);
-		}
-	}
+	strbuf_addstr(&submodule_sb, submodule);
+	if (is_nonbare_repository_dir(&submodule_sb))
+		refs = ref_store_init(submodule);
+	strbuf_release(&submodule_sb);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v3 11/16] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

This is the last function in this code (besides public API) that takes
submodule argument and handles both main/submodule cases. Break it down,
move main store registration in get_main_ref_store() and keep the rest
in register_submodule_ref_store().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/refs.c b/refs.c
index 76a0e7b5a..55a80a83d 100644
--- a/refs.c
+++ b/refs.c
@@ -1402,25 +1402,19 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 
 /*
  * Register the specified ref_store to be the one that should be used
- * for submodule (or the main repository if submodule is NULL). It is
- * a fatal error to call this function twice for the same submodule.
+ * for submodule. It is a fatal error to call this function twice for
+ * the same submodule.
  */
-static void register_ref_store(struct ref_store *refs, const char *submodule)
+static void register_submodule_ref_store(struct ref_store *refs,
+					 const char *submodule)
 {
-	if (!submodule) {
-		if (main_ref_store)
-			die("BUG: main_ref_store initialized twice");
-
-		main_ref_store = refs;
-	} else {
-		if (!submodule_ref_stores.tablesize)
-			hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
+	if (!submodule_ref_stores.tablesize)
+		hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
 
-		if (hashmap_put(&submodule_ref_stores,
-				alloc_submodule_hash_entry(submodule, refs)))
-			die("BUG: ref_store for submodule '%s' initialized twice",
-			    submodule);
-	}
+	if (hashmap_put(&submodule_ref_stores,
+			alloc_submodule_hash_entry(submodule, refs)))
+		die("BUG: ref_store for submodule '%s' initialized twice",
+		    submodule);
 }
 
 /*
@@ -1437,7 +1431,6 @@ static struct ref_store *ref_store_init(const char *submodule)
 		die("BUG: reference backend %s is unknown", be_name);
 
 	refs = be->init(submodule);
-	register_ref_store(refs, submodule);
 	return refs;
 }
 
@@ -1449,6 +1442,12 @@ static struct ref_store *get_main_ref_store(void)
 		return main_ref_store;
 
 	refs = ref_store_init(NULL);
+	if (refs) {
+		if (main_ref_store)
+			die("BUG: main_ref_store initialized twice");
+
+		main_ref_store = refs;
+	}
 	return refs;
 }
 
@@ -1469,6 +1468,9 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (is_nonbare_repository_dir(&submodule_sb))
 		refs = ref_store_init(submodule);
 	strbuf_release(&submodule_sb);
+
+	if (refs)
+		register_submodule_ref_store(refs, submodule);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

Re: [PATCH v3 11/16] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Junio C Hamano]

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> This is the last function in this code (besides public API) that takes
> submodule argument and handles both main/submodule cases. Break it down,
> move main store registration in get_main_ref_store() and keep the rest
> in register_submodule_ref_store().

Very nice.

[PATCH v3 12/16] refs.c: make get_main_ref_store() public and use it

[Nguyễn Thái Ngọc Duy]

get_ref_store() will soon be renamed to get_submodule_ref_store().
Together with future get_worktree_ref_store(), the three functions
provide an appropriate ref store for different operation modes. New APIs
will be added to operate directly on ref stores.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 36 ++++++++++++++++++------------------
 refs.h |  2 ++
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/refs.c b/refs.c
index 55a80a83d..25f657a6f 100644
--- a/refs.c
+++ b/refs.c
@@ -1303,7 +1303,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->init_db(refs, err);
 }
@@ -1311,7 +1311,7 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_ref_store(NULL), refname,
+	return resolve_ref_recursively(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1434,7 +1434,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
-static struct ref_store *get_main_ref_store(void)
+struct ref_store *get_main_ref_store(void)
 {
 	struct ref_store *refs;
 
@@ -1483,14 +1483,14 @@ void base_ref_store_init(struct ref_store *refs,
 /* backend functions */
 int pack_refs(unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->pack_refs(refs, flags);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->peel_ref(refs, refname, sha1);
 }
@@ -1498,7 +1498,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_symref(refs, ref_target, refs_heads_master,
 				       logmsg);
@@ -1507,7 +1507,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1517,14 +1517,14 @@ int verify_refname_available(const char *refname,
 			     const struct string_list *skip,
 			     struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
 }
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1535,7 +1535,7 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent_reverse(refs, refname,
 						     fn, cb_data);
@@ -1544,14 +1544,14 @@ int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_exists(refs, refname);
 }
@@ -1559,14 +1559,14 @@ int reflog_exists(const char *refname)
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_reflog(refs, refname);
 }
@@ -1578,7 +1578,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_expire(refs, refname, sha1, flags,
 				       prepare_fn, should_prune_fn,
@@ -1588,21 +1588,21 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
 int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_refs(refs, refnames, flags);
 }
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index 694784391..f803528fc 100644
--- a/refs.h
+++ b/refs.h
@@ -553,4 +553,6 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 
 int ref_storage_backend_exists(const char *name);
 
+struct ref_store *get_main_ref_store(void);
+
 #endif /* REFS_H */
-- 
2.11.0.157.gd943d85

[PATCH v3 13/16] path.c: move some code out of strbuf_git_path_submodule()

[Nguyễn Thái Ngọc Duy]

refs is learning to avoid path rewriting that is done by
strbuf_git_path_submodule(). Factor out this code so it could be reused
by refs*

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 path.c      | 34 +++++++---------------------------
 submodule.c | 31 +++++++++++++++++++++++++++++++
 submodule.h |  1 +
 3 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/path.c b/path.c
index efcedafba..3451d2916 100644
--- a/path.c
+++ b/path.c
@@ -475,35 +475,16 @@ const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 static int do_submodule_path(struct strbuf *buf, const char *path,
 			     const char *fmt, va_list args)
 {
-	const char *git_dir;
 	struct strbuf git_submodule_common_dir = STRBUF_INIT;
 	struct strbuf git_submodule_dir = STRBUF_INIT;
-	const struct submodule *sub;
-	int err = 0;
+	int ret;
 
-	strbuf_addstr(buf, path);
-	strbuf_complete(buf, '/');
-	strbuf_addstr(buf, ".git");
-
-	git_dir = read_gitfile(buf->buf);
-	if (git_dir) {
-		strbuf_reset(buf);
-		strbuf_addstr(buf, git_dir);
-	}
-	if (!is_git_directory(buf->buf)) {
-		gitmodules_config();
-		sub = submodule_from_path(null_sha1, path);
-		if (!sub) {
-			err = SUBMODULE_PATH_ERR_NOT_CONFIGURED;
-			goto cleanup;
-		}
-		strbuf_reset(buf);
-		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
-	}
-
-	strbuf_addch(buf, '/');
-	strbuf_addbuf(&git_submodule_dir, buf);
+	ret = submodule_to_gitdir(&git_submodule_dir, path);
+	if (ret)
+		goto cleanup;
 
+	strbuf_complete(&git_submodule_dir, '/');
+	strbuf_addbuf(buf, &git_submodule_dir);
 	strbuf_vaddf(buf, fmt, args);
 
 	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
@@ -514,8 +495,7 @@ static int do_submodule_path(struct strbuf *buf, const char *path,
 cleanup:
 	strbuf_release(&git_submodule_dir);
 	strbuf_release(&git_submodule_common_dir);
-
-	return err;
+	return ret;
 }
 
 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
diff --git a/submodule.c b/submodule.c
index ece17315d..3ce589d55 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1335,3 +1335,34 @@ void prepare_submodule_repo_env(struct argv_array *out)
 	}
 	argv_array_push(out, "GIT_DIR=.git");
 }
+
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
+{
+	const struct submodule *sub;
+	const char *git_dir;
+	int ret = 0;
+
+	strbuf_reset(buf);
+	strbuf_addstr(buf, submodule);
+	strbuf_complete(buf, '/');
+	strbuf_addstr(buf, ".git");
+
+	git_dir = read_gitfile(buf->buf);
+	if (git_dir) {
+		strbuf_reset(buf);
+		strbuf_addstr(buf, git_dir);
+	}
+	if (!is_git_directory(buf->buf)) {
+		gitmodules_config();
+		sub = submodule_from_path(null_sha1, submodule);
+		if (!sub) {
+			ret = -1;
+			goto cleanup;
+		}
+		strbuf_reset(buf);
+		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
+	}
+
+cleanup:
+	return ret;
+}
diff --git a/submodule.h b/submodule.h
index 23d76682b..2728494ce 100644
--- a/submodule.h
+++ b/submodule.h
@@ -70,6 +70,7 @@ extern int push_unpushed_submodules(struct sha1_array *commits,
 				    int dry_run);
 void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
 int parallel_submodules(void);
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 /*
  * Prepare the "env_array" parameter of a "struct child_process" for executing
-- 
2.11.0.157.gd943d85

[PATCH v3 14/16] refs: move submodule code out of files-backend.c

[Nguyễn Thái Ngọc Duy]

files-backend is now initialized with a $GIT_DIR. Converting a submodule
path to where real submodule gitdir is located is done in get_ref_store().

The new code in init_submodule_ref_store() is basically a copy of
strbuf_git_path_submodule().

This gives a slight performance improvement for submodules since we
don't convert submodule path to gitdir at every backend call like
before. We pay that once at ref-store creation.

More cleanup in files_downcast() follows shortly. It's separate to keep
noises from this patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 18 +++++++++++++-----
 refs/files-backend.c | 22 ++++++----------------
 refs/refs-internal.h |  6 +++---
 3 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/refs.c b/refs.c
index 25f657a6f..58ac9a2a8 100644
--- a/refs.c
+++ b/refs.c
@@ -9,6 +9,7 @@
 #include "refs/refs-internal.h"
 #include "object.h"
 #include "tag.h"
+#include "submodule.h"
 
 /*
  * List of all available backends
@@ -1419,9 +1420,9 @@ static void register_submodule_ref_store(struct ref_store *refs,
 
 /*
  * Create, record, and return a ref_store instance for the specified
- * submodule (or the main repository if submodule is NULL).
+ * gitdir (or the main repository if gitdir is NULL).
  */
-static struct ref_store *ref_store_init(const char *submodule)
+static struct ref_store *ref_store_init(const char *gitdir)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1430,7 +1431,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(submodule);
+	refs = be->init(gitdir);
 	return refs;
 }
 
@@ -1455,6 +1456,7 @@ struct ref_store *get_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
+	int ret;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
@@ -1465,8 +1467,14 @@ struct ref_store *get_ref_store(const char *submodule)
 		return refs;
 
 	strbuf_addstr(&submodule_sb, submodule);
-	if (is_nonbare_repository_dir(&submodule_sb))
-		refs = ref_store_init(submodule);
+	ret = is_nonbare_repository_dir(&submodule_sb);
+	strbuf_release(&submodule_sb);
+	if (!ret)
+		return refs;
+
+	ret = submodule_to_gitdir(&submodule_sb, submodule);
+	if (!ret)
+		refs = ref_store_init(submodule_sb.buf);
 	strbuf_release(&submodule_sb);
 
 	if (refs)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 07cf2cb93..627466043 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -917,13 +917,6 @@ struct packed_ref_cache {
 struct files_ref_store {
 	struct ref_store base;
 
-	/*
-	 * The name of the submodule represented by this object, or
-	 * NULL if it represents the main repository's reference
-	 * store:
-	 */
-	const char *submodule;
-
 	struct strbuf gitdir;
 	struct strbuf gitcommondir;
 
@@ -945,10 +938,7 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
 	va_end(vap);
-	if (refs->submodule)
-		strbuf_git_path_submodule(sb, refs->submodule,
-					  "%s", tmp.buf);
-	else if (!strcmp(tmp.buf, "packed-refs") || !strcmp(tmp.buf, "logs"))
+	if (!strcmp(tmp.buf, "packed-refs") || !strcmp(tmp.buf, "logs"))
 		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
 	else if (is_per_worktree_ref(tmp.buf) ||
 		 (skip_prefix(tmp.buf, "logs/", &ref) &&
@@ -1007,7 +997,7 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *submodule)
+static struct ref_store *files_ref_store_create(const char *gitdir)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
@@ -1017,8 +1007,9 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 	strbuf_init(&refs->gitdir, 0);
 	strbuf_init(&refs->gitcommondir, 0);
 
-	if (submodule) {
-		refs->submodule = xstrdup(submodule);
+	if (gitdir) {
+		strbuf_addstr(&refs->gitdir, gitdir);
+		get_common_dir_noenv(&refs->gitcommondir, gitdir);
 	} else {
 		strbuf_addstr(&refs->gitdir, get_git_dir());
 		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
@@ -1034,8 +1025,7 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	if (refs->submodule)
-		die("BUG: %s called for a submodule", caller);
+	/* This function is to be deleted in the next patch */
 }
 
 /*
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 69d02b6ba..d7112770d 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -476,12 +476,12 @@ struct ref_store;
 /* refs backends */
 
 /*
- * Initialize the ref_store for the specified submodule, or for the
- * main repository if submodule == NULL. These functions should call
+ * Initialize the ref_store for the specified gitdir, or for the
+ * current repository if gitdir == NULL. These functions should call
  * base_ref_store_init() to initialize the shared part of the
  * ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *submodule);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
-- 
2.11.0.157.gd943d85

[PATCH v3 15/16] files-backend: remove submodule_allowed from files_downcast()

[Nguyễn Thái Ngọc Duy]

Since submodule or not is irrelevant to files-backend after the last
patch, remove the parameter from files_downcast() and kill
files_assert_main_repository().

PS. This implies that all ref operations are allowed for submodules. But
we may need to look more closely to see if that's really true...

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 70 ++++++++++++++++------------------------------------
 1 file changed, 21 insertions(+), 49 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 627466043..d35032fcd 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1019,24 +1019,13 @@ static struct ref_store *files_ref_store_create(const char *gitdir)
 }
 
 /*
- * Die if refs is for a submodule (i.e., not for the main repository).
- * caller is used in any necessary error messages.
- */
-static void files_assert_main_repository(struct files_ref_store *refs,
-					 const char *caller)
-{
-	/* This function is to be deleted in the next patch */
-}
-
-/*
  * Downcast ref_store to files_ref_store. Die if ref_store is not a
  * files_ref_store. If submodule_allowed is not true, then also die if
  * files_ref_store is for a submodule (i.e., not for the main
  * repository). caller is used in any necessary error messages.
  */
-static struct files_ref_store *files_downcast(
-		struct ref_store *ref_store, int submodule_allowed,
-		const char *caller)
+static struct files_ref_store *files_downcast(struct ref_store *ref_store,
+					      const char *caller)
 {
 	struct files_ref_store *refs;
 
@@ -1046,9 +1035,6 @@ static struct files_ref_store *files_downcast(
 
 	refs = (struct files_ref_store *)ref_store;
 
-	if (!submodule_allowed)
-		files_assert_main_repository(refs, caller);
-
 	return refs;
 }
 
@@ -1384,7 +1370,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "read_raw_ref");
+		files_downcast(ref_store, "read_raw_ref");
 	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
@@ -1577,7 +1563,6 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	int ret = TRANSACTION_GENERIC_ERROR;
 
 	assert(err);
-	files_assert_main_repository(refs, "lock_raw_ref");
 
 	*type = 0;
 
@@ -1801,7 +1786,7 @@ static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
 static int files_peel_ref(struct ref_store *ref_store,
 			  const char *refname, unsigned char *sha1)
 {
-	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
+	struct files_ref_store *refs = files_downcast(ref_store, "peel_ref");
 	int flag;
 	unsigned char base[20];
 
@@ -1910,7 +1895,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 		const char *prefix, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "ref_iterator_begin");
+		files_downcast(ref_store, "ref_iterator_begin");
 	struct ref_dir *loose_dir, *packed_dir;
 	struct ref_iterator *loose_iter, *packed_iter;
 	struct files_ref_iterator *iter;
@@ -2043,7 +2028,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	int attempts_remaining = 3;
 	int resolved;
 
-	files_assert_main_repository(refs, "lock_ref_sha1_basic");
 	assert(err);
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
@@ -2191,8 +2175,6 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	files_assert_main_repository(refs, "lock_packed_refs");
-
 	if (!timeout_configured) {
 		git_config_get_int("core.packedrefstimeout", &timeout_value);
 		timeout_configured = 1;
@@ -2232,8 +2214,6 @@ static int commit_packed_refs(struct files_ref_store *refs)
 	int save_errno = 0;
 	FILE *out;
 
-	files_assert_main_repository(refs, "commit_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 
@@ -2265,8 +2245,6 @@ static void rollback_packed_refs(struct files_ref_store *refs)
 	struct packed_ref_cache *packed_ref_cache =
 		get_packed_ref_cache(refs);
 
-	files_assert_main_repository(refs, "rollback_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 	rollback_lock_file(packed_ref_cache->lock);
@@ -2412,7 +2390,7 @@ static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "pack_refs");
+		files_downcast(ref_store, "pack_refs");
 	struct pack_refs_cb_data cbdata;
 
 	memset(&cbdata, 0, sizeof(cbdata));
@@ -2445,7 +2423,6 @@ static int repack_without_refs(struct files_ref_store *refs,
 	struct string_list_item *refname;
 	int ret, needs_repacking = 0, removed = 0;
 
-	files_assert_main_repository(refs, "repack_without_refs");
 	assert(err);
 
 	/* Look for a packed ref */
@@ -2513,7 +2490,7 @@ static int files_delete_refs(struct ref_store *ref_store,
 			     struct string_list *refnames, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_refs");
+		files_downcast(ref_store, "delete_refs");
 	struct strbuf err = STRBUF_INIT;
 	int i, result = 0;
 
@@ -2621,7 +2598,7 @@ static int files_verify_refname_available(struct ref_store *ref_store,
 					  struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "verify_refname_available");
+		files_downcast(ref_store, "verify_refname_available");
 	struct ref_dir *packed_refs = get_packed_refs(refs);
 	struct ref_dir *loose_refs = get_loose_refs(refs);
 
@@ -2646,7 +2623,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			    const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "rename_ref");
+		files_downcast(ref_store, "rename_ref");
 	unsigned char sha1[20], orig_sha1[20];
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
@@ -2868,7 +2845,7 @@ static int files_create_reflog(struct ref_store *ref_store,
 	int ret;
 	struct strbuf sb = STRBUF_INIT;
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_reflog");
+		files_downcast(ref_store, "create_reflog");
 
 	ret = log_ref_setup(refs, refname, &sb, err, force_create);
 	strbuf_release(&sb);
@@ -3006,8 +2983,6 @@ static int commit_ref_update(struct files_ref_store *refs,
 			     const unsigned char *sha1, const char *logmsg,
 			     struct strbuf *err)
 {
-	files_assert_main_repository(refs, "commit_ref_update");
-
 	clear_loose_ref_cache(refs);
 	if (log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
 			  sha1, logmsg, 0, err)) {
@@ -3116,7 +3091,7 @@ static int files_create_symref(struct ref_store *ref_store,
 			       const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_symref");
+		files_downcast(ref_store, "create_symref");
 	struct strbuf err = STRBUF_INIT;
 	struct ref_lock *lock;
 	int ret;
@@ -3142,7 +3117,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
+		files_downcast(get_ref_store(NULL), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3180,7 +3155,7 @@ static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_exists");
+		files_downcast(ref_store, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
@@ -3195,7 +3170,7 @@ static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_reflog");
+		files_downcast(ref_store, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
@@ -3250,7 +3225,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
+		files_downcast(ref_store, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
@@ -3358,7 +3333,7 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent");
+		files_downcast(ref_store, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
@@ -3446,7 +3421,7 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_iterator_begin");
+		files_downcast(ref_store, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
@@ -3658,8 +3633,6 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 	int ret;
 	struct ref_lock *lock;
 
-	files_assert_main_repository(refs, "lock_ref_for_update");
-
 	if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
 		update->flags |= REF_DELETING;
 
@@ -3784,7 +3757,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 				    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "ref_transaction_commit");
+		files_downcast(ref_store, "ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
@@ -3958,7 +3931,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 					    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "initial_ref_transaction_commit");
+		files_downcast(ref_store, "initial_ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
@@ -4080,7 +4053,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			       void *policy_cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_expire");
+		files_downcast(ref_store, "reflog_expire");
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
@@ -4185,8 +4158,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "init_db");
+	struct files_ref_store *refs = files_downcast(ref_store, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
 	/*
-- 
2.11.0.157.gd943d85

[PATCH v3 16/16] refs: rename get_ref_store() to get_submodule_ref_store() and make it public

[Nguyễn Thái Ngọc Duy]

This function is intended to replace *_submodule() refs API. It provides
a ref store for a specific submodule, which can be operated on by a new
set of refs API.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 12 ++++++++----
 refs.h               | 11 +++++++++++
 refs/files-backend.c |  2 +-
 refs/refs-internal.h | 12 ------------
 4 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/refs.c b/refs.c
index 58ac9a2a8..e7206a420 100644
--- a/refs.c
+++ b/refs.c
@@ -1160,7 +1160,7 @@ int head_ref(each_ref_fn fn, void *cb_data)
 static int do_for_each_ref(const char *submodule, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(submodule);
+	struct ref_store *refs = get_submodule_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
@@ -1333,10 +1333,10 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
 		/* We need to strip off one or more trailing slashes */
 		char *stripped = xmemdupz(submodule, len);
 
-		refs = get_ref_store(stripped);
+		refs = get_submodule_ref_store(stripped);
 		free(stripped);
 	} else {
-		refs = get_ref_store(submodule);
+		refs = get_submodule_ref_store(submodule);
 	}
 
 	if (!refs)
@@ -1452,13 +1452,17 @@ struct ref_store *get_main_ref_store(void)
 	return refs;
 }
 
-struct ref_store *get_ref_store(const char *submodule)
+struct ref_store *get_submodule_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 	int ret;
 
 	if (!submodule || !*submodule) {
+		/*
+		 * FIXME: This case is ideally not allowed. But that
+		 * can't happen until we clean up all the callers.
+		 */
 		return get_main_ref_store();
 	}
 
diff --git a/refs.h b/refs.h
index f803528fc..1287ba59c 100644
--- a/refs.h
+++ b/refs.h
@@ -554,5 +554,16 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int ref_storage_backend_exists(const char *name);
 
 struct ref_store *get_main_ref_store(void);
+/*
+ * Return the ref_store instance for the specified submodule. For the
+ * main repository, use submodule==NULL; such a call cannot fail. For
+ * a submodule, the submodule must exist and be a nonbare repository,
+ * otherwise return NULL. If the requested reference store has not yet
+ * been initialized, initialize it first.
+ *
+ * For backwards compatibility, submodule=="" is treated the same as
+ * submodule==NULL.
+ */
+struct ref_store *get_submodule_ref_store(const char *submodule);
 
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index d35032fcd..82be3f90f 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3117,7 +3117,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), "set_head_symref");
+		files_downcast(get_main_ref_store(), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index d7112770d..cb6882779 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -634,18 +634,6 @@ struct ref_store {
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-/*
- * Return the ref_store instance for the specified submodule. For the
- * main repository, use submodule==NULL; such a call cannot fail. For
- * a submodule, the submodule must exist and be a nonbare repository,
- * otherwise return NULL. If the requested reference store has not yet
- * been initialized, initialize it first.
- *
- * For backwards compatibility, submodule=="" is treated the same as
- * submodule==NULL.
- */
-struct ref_store *get_ref_store(const char *submodule);
-
 const char *resolve_ref_recursively(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
-- 
2.11.0.157.gd943d85

[PATCH v4 00/15] Remove submodule from files-backend.c

[Nguyễn Thái Ngọc Duy]

v4:

 - is based on master+mh/ref-remove-empty-directory+mh/submodule-hash
   instead of mh/submodule-hash alone. It could merge with pu cleanly.

 - 06/16 from v5, "correct is_per_worktree_ref", is removed. The
   "remove the use of git_path" patch is updated to handle it
   correctly even without that patch. More on this later.

 - update "replace" typo in a commit message

The story behind the 06/16 removal is, in my simple view, there are
per-repo and per-worktree refs. But refs.c and backends see them as
three types: per-worktree, pseudo and normal/per-repo. Refs like
ORIG_HEAD are _both_ per-worktree and pseudo.

06/16 reclassifies ORIG_HEAD from pseudo to per-worktree, which
triggers a failure in t1400 because as pseudo refs, reflog will not be
created while it will be for per-worktree. This new test is on master,
not maint. I now fall back to treating both per-worktree and pseudo as
per-worktree in files_path() only and keep classification unchanged.

Side note, my other two series seem to apply cleanly on top of this
v3, so no resend.

Nguyễn Thái Ngọc Duy (15):
  refs-internal.c: make files_log_ref_write() static
  files-backend: convert git_path() to strbuf_git_path()
  files-backend: add files_path()
  files-backend: replace *git_path*() with files_path()
  refs.c: share is_per_worktree_ref() to files-backend.c
  files-backend: remove the use of git_path()
  refs.c: introduce get_main_ref_store()
  refs: rename lookup_ref_store() to lookup_submodule_ref_store()
  refs.c: flatten get_ref_store() a bit
  refs.c: kill register_ref_store(), add register_submodule_ref_store()
  refs.c: make get_main_ref_store() public and use it
  path.c: move some code out of strbuf_git_path_submodule()
  refs: move submodule code out of files-backend.c
  files-backend: remove submodule_allowed from files_downcast()
  refs: rename get_ref_store() to get_submodule_ref_store() and make it public

 path.c               |  34 +----
 refs.c               | 144 +++++++++---------
 refs.h               |  13 ++
 refs/files-backend.c | 406 ++++++++++++++++++++++++++++++++-------------------
 refs/refs-internal.h |  28 ++--
 submodule.c          |  31 ++++
 submodule.h          |   1 +
 7 files changed, 396 insertions(+), 261 deletions(-)

-- 
2.11.0.157.gd943d85

[PATCH v4 01/15] refs-internal.c: make files_log_ref_write() static

[Nguyễn Thái Ngọc Duy]

Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
but probably never used outside refs-internal.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 3 +++
 refs/refs-internal.h | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index db3bd42a9..1ebd59ec0 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+			       const unsigned char *new_sha1, const char *msg,
+			       int flags, struct strbuf *err);
 
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index fa93c9a32..f732473e1 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -228,10 +228,6 @@ struct ref_transaction {
 	enum ref_transaction_state state;
 };
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err);
-
 /*
  * Check for entries in extras that are within the specified
  * directory, where dirname is a reference directory name including
-- 
2.11.0.157.gd943d85

[PATCH v4 02/15] files-backend: convert git_path() to strbuf_git_path()

[Nguyễn Thái Ngọc Duy]

git_path() and friends are going to be killed in files-backend.c in near
future. And because there's a risk with overwriting buffer in
git_path(), let's convert them all to strbuf_git_path(). We'll have
easier time killing/converting strbuf_git_path() then because we won't
have to worry about memory management again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 146 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 115 insertions(+), 31 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 1ebd59ec0..c6c86f850 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2151,6 +2151,8 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	static int timeout_configured = 0;
 	static int timeout_value = 1000;
 	struct packed_ref_cache *packed_ref_cache;
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
 
 	files_assert_main_repository(refs, "lock_packed_refs");
 
@@ -2159,10 +2161,13 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	if (hold_lock_file_for_update_timeout(
-			    &packlock, git_path("packed-refs"),
-			    flags, timeout_value) < 0)
+	strbuf_git_path(&sb, "packed-refs");
+	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
+						flags, timeout_value);
+	strbuf_release(&sb);
+	if (ret < 0)
 		return -1;
+
 	/*
 	 * Get the current packed-refs while holding the lock.  If the
 	 * packed-refs file has been modified since we last read it,
@@ -2312,6 +2317,7 @@ enum {
 static void try_remove_empty_parents(const char *refname, unsigned int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 	char *p, *q;
 	int i;
 
@@ -2333,14 +2339,19 @@ static void try_remove_empty_parents(const char *refname, unsigned int flags)
 		if (q == p)
 			break;
 		strbuf_setlen(&buf, q - buf.buf);
-		if ((flags & REMOVE_EMPTY_PARENTS_REF) &&
-		    rmdir(git_path("%s", buf.buf)))
+
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "%s", buf.buf);
+		if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REF;
-		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) &&
-		    rmdir(git_path("logs/%s", buf.buf)))
+
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "logs/%s", buf.buf);
+		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
 	}
 	strbuf_release(&buf);
+	strbuf_release(&sb);
 }
 
 /* make sure nobody touched the ref, and unlink */
@@ -2426,7 +2437,11 @@ static int repack_without_refs(struct files_ref_store *refs,
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(refs, 0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "packed-refs");
+		unable_to_lock_message(sb.buf, errno, err);
+		strbuf_release(&sb);
 		return -1;
 	}
 	packed = get_packed_refs(refs);
@@ -2504,9 +2519,11 @@ static int files_delete_refs(struct ref_store *ref_store,
 
 static int rename_tmp_log_callback(const char *path, void *cb)
 {
+	struct strbuf sb = STRBUF_INIT;
 	int *true_errno = cb;
 
-	if (rename(git_path(TMP_RENAMED_LOG), path)) {
+	strbuf_git_path(&sb, TMP_RENAMED_LOG);
+	if (rename(sb.buf, path)) {
 		/*
 		 * rename(a, b) when b is an existing directory ought
 		 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
@@ -2515,30 +2532,40 @@ static int rename_tmp_log_callback(const char *path, void *cb)
 		 * that it knows to retry.
 		 */
 		*true_errno = errno;
+		strbuf_release(&sb);
 		if (errno == ENOTDIR)
 			errno = EISDIR;
 		return -1;
 	} else {
+		strbuf_release(&sb);
 		return 0;
 	}
 }
 
 static int rename_tmp_log(const char *newrefname)
 {
-	char *path = git_pathdup("logs/%s", newrefname);
+	struct strbuf sb = STRBUF_INIT;
+	const char *path;
 	int ret, true_errno;
 
+	strbuf_git_path(&sb, "logs/%s", newrefname);
+	path = sb.buf;
 	ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
 	if (ret) {
 		if (errno == EISDIR)
 			error("directory not empty: %s", path);
-		else
+		else {
+			struct strbuf tmp_renamed = STRBUF_INIT;
+
+			strbuf_git_path(&tmp_renamed, TMP_RENAMED_LOG);
 			error("unable to move logfile %s to %s: %s",
-			      git_path(TMP_RENAMED_LOG), path,
+			      tmp_renamed.buf, path,
 			      strerror(true_errno));
+			strbuf_release(&tmp_renamed);
+		}
 	}
 
-	free(path);
+	strbuf_release(&sb);
 	return ret;
 }
 
@@ -2579,9 +2606,15 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
-	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+	struct strbuf sb_oldref = STRBUF_INIT;
+	struct strbuf sb_newref = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
+	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	log = !lstat(sb_oldref.buf, &loginfo);
+	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2595,7 +2628,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
+	if (ret)
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
@@ -2674,13 +2712,19 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
+	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
+	strbuf_release(&sb_newref);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
 
 	return 1;
 }
@@ -2854,18 +2898,24 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
 				  git_committer_info(0), msg);
 	if (result) {
+		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
+		strbuf_git_path(&sb, "logs/%s", refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
-			    git_path("logs/%s", refname), strerror(save_errno));
+			    sb.buf, strerror(save_errno));
+		strbuf_release(&sb);
 		close(logfd);
 		return -1;
 	}
 	if (close(logfd)) {
+		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
+		strbuf_git_path(&sb, "logs/%s", refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
-			    git_path("logs/%s", refname), strerror(save_errno));
+			    sb.buf, strerror(save_errno));
+		strbuf_release(&sb);
 		return -1;
 	}
 	return 0;
@@ -3085,22 +3135,32 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
+	int ret;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_exists");
 
-	return !lstat(git_path("logs/%s", refname), &st) &&
-		S_ISREG(st.st_mode);
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "delete_reflog");
 
-	return remove_path(git_path("logs/%s", refname));
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = remove_path(sb.buf);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
@@ -3155,7 +3215,9 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3261,7 +3323,9 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3343,12 +3407,15 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 {
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
+	struct strbuf sb = STRBUF_INIT;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_iterator_begin");
 
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	iter->dir_iterator = dir_iterator_begin(git_path("logs"));
+	strbuf_git_path(&sb, "logs");
+	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	strbuf_release(&sb);
 	return ref_iterator;
 }
 
@@ -3686,6 +3753,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	char *head_ref = NULL;
 	int head_type;
 	struct object_id head_oid;
+	struct strbuf sb = STRBUF_INIT;
 
 	assert(err);
 
@@ -3807,7 +3875,9 @@ static int files_transaction_commit(struct ref_store *ref_store,
 			if (!(update->type & REF_ISPACKED) ||
 			    update->type & REF_ISSYMREF) {
 				/* It is a loose reference. */
-				if (unlink_or_msg(git_path("%s", lock->ref_name), err)) {
+				strbuf_reset(&sb);
+				strbuf_git_path(&sb, "%s", lock->ref_name);
+				if (unlink_or_msg(sb.buf, err)) {
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto cleanup;
 				}
@@ -3827,9 +3897,13 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 	/* Delete the reflogs of any references that were deleted: */
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
-		if (!unlink_or_warn(git_path("logs/%s", ref_to_delete->string)))
+		struct strbuf sb = STRBUF_INIT;
+
+		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		if (!unlink_or_warn(sb.buf))
 			try_remove_empty_parents(ref_to_delete->string,
 						 REMOVE_EMPTY_PARENTS_REFLOG);
+		strbuf_release(&sb);
 	}
 
 	clear_loose_ref_cache(refs);
@@ -4101,18 +4175,28 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct strbuf sb = STRBUF_INIT;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "init_db");
 
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	strbuf_git_path(&sb, "refs/heads");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
+	strbuf_git_path(&sb, "refs/tags");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		strbuf_git_path(&sb, "refs/heads");
+		adjust_shared_perm(sb.buf);
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "refs/tags");
+		adjust_shared_perm(sb.buf);
 	}
+	strbuf_release(&sb);
 	return 0;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v4 03/15] files-backend: add files_path()

[Nguyễn Thái Ngọc Duy]

This will be the replacement for both git_path() and git_path_submodule()
in this file. The idea is backend takes a git path and use that,
oblivious of submodule, linked worktrees and such.

This is the middle step towards that. Eventually the "submodule" field
in 'struct files_ref_store' should be replaced by "gitdir". And a
compound ref_store is created to combine two files backends together,
one represents the shared refs in $GIT_COMMON_DIR, one per-worktree. At
that point, files_path() becomes a wrapper of strbuf_vaddf().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index c6c86f850..7eaf28bd6 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -930,6 +930,24 @@ struct files_ref_store {
 /* Lock used for the main packed-refs file: */
 static struct lock_file packlock;
 
+__attribute__((format (printf, 3, 4)))
+static void files_path(struct files_ref_store *refs, struct strbuf *sb,
+		       const char *fmt, ...)
+{
+	struct strbuf tmp = STRBUF_INIT;
+	va_list vap;
+
+	va_start(vap, fmt);
+	strbuf_vaddf(&tmp, fmt, vap);
+	va_end(vap);
+	if (refs->submodule)
+		strbuf_git_path_submodule(sb, refs->submodule,
+					  "%s", tmp.buf);
+	else
+		strbuf_git_path(sb, "%s", tmp.buf);
+	strbuf_release(&tmp);
+}
+
 /*
  * Increment the reference count of *packed_refs.
  */
-- 
2.11.0.157.gd943d85

[PATCH v4 04/15] files-backend: replace *git_path*() with files_path()

[Nguyễn Thái Ngọc Duy]

This centralizes all path rewriting of files-backend.c in one place so
we have easier time removing the path rewriting later. There could be
some hidden indirect git_path() though, I didn't audit the code to the
bottom.

Side note: set_worktree_head_symref() is a bad boy and should not be in
files-backend.c (probably should not exist in the first place). But
we'll leave it there until we have better multi-worktree support in refs
before we update it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 208 +++++++++++++++++++++++++++------------------------
 1 file changed, 111 insertions(+), 97 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 7eaf28bd6..b599ddf92 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,7 +165,8 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
-static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int files_log_ref_write(struct files_ref_store *refs,
+			       const char *refname, const unsigned char *old_sha1,
 			       const unsigned char *new_sha1, const char *msg,
 			       int flags, struct strbuf *err);
 
@@ -1178,12 +1179,10 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
 {
 	char *packed_refs_file;
+	struct strbuf sb = STRBUF_INIT;
 
-	if (refs->submodule)
-		packed_refs_file = git_pathdup_submodule(refs->submodule,
-							 "packed-refs");
-	else
-		packed_refs_file = git_pathdup("packed-refs");
+	files_path(refs, &sb, "packed-refs");
+	packed_refs_file = strbuf_detach(&sb, NULL);
 
 	if (refs->packed &&
 	    !stat_validity_check(&refs->packed->validity, packed_refs_file))
@@ -1249,10 +1248,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 	size_t path_baselen;
 	int err = 0;
 
-	if (refs->submodule)
-		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
-	else
-		strbuf_git_path(&path, "%s", dirname);
+	files_path(refs, &path, "%s", dirname);
 	path_baselen = path.len;
 
 	if (err) {
@@ -1394,10 +1390,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	*type = 0;
 	strbuf_reset(&sb_path);
 
-	if (refs->submodule)
-		strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
-	else
-		strbuf_git_path(&sb_path, "%s", refname);
+	files_path(refs, &sb_path, "%s", refname);
 
 	path = sb_path.buf;
 
@@ -1585,7 +1578,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	*lock_p = lock = xcalloc(1, sizeof(*lock));
 
 	lock->ref_name = xstrdup(refname);
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 
 retry:
 	switch (safe_create_leading_directories(ref_file.buf)) {
@@ -2057,7 +2050,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	if (flags & REF_DELETING)
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_path(refs, &ref_file, "%s", refname);
 	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
 					lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
@@ -2179,7 +2172,7 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 		timeout_configured = 1;
 	}
 
-	strbuf_git_path(&sb, "packed-refs");
+	files_path(refs, &sb, "packed-refs");
 	ret = hold_lock_file_for_update_timeout(&packlock, sb.buf,
 						flags, timeout_value);
 	strbuf_release(&sb);
@@ -2332,7 +2325,9 @@ enum {
  * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
  * REMOVE_EMPTY_PARENTS_REFLOG.
  */
-static void try_remove_empty_parents(const char *refname, unsigned int flags)
+static void try_remove_empty_parents(struct files_ref_store *refs,
+				     const char *refname,
+				     unsigned int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
@@ -2359,12 +2354,12 @@ static void try_remove_empty_parents(const char *refname, unsigned int flags)
 		strbuf_setlen(&buf, q - buf.buf);
 
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "%s", buf.buf);
+		files_path(refs, &sb, "%s", buf.buf);
 		if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REF;
 
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "logs/%s", buf.buf);
+		files_path(refs, &sb, "logs/%s", buf.buf);
 		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
 	}
@@ -2373,7 +2368,7 @@ static void try_remove_empty_parents(const char *refname, unsigned int flags)
 }
 
 /* make sure nobody touched the ref, and unlink */
-static void prune_ref(struct ref_to_prune *r)
+static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -2395,10 +2390,10 @@ static void prune_ref(struct ref_to_prune *r)
 	strbuf_release(&err);
 }
 
-static void prune_refs(struct ref_to_prune *r)
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	while (r) {
-		prune_ref(r);
+		prune_ref(refs, r);
 		r = r->next;
 	}
 }
@@ -2421,7 +2416,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 	if (commit_packed_refs(refs))
 		die_errno("unable to overwrite old ref-pack file");
 
-	prune_refs(cbdata.ref_to_prune);
+	prune_refs(refs, cbdata.ref_to_prune);
 	return 0;
 }
 
@@ -2457,7 +2452,7 @@ static int repack_without_refs(struct files_ref_store *refs,
 	if (lock_packed_refs(refs, 0)) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "packed-refs");
+		files_path(refs, &sb, "packed-refs");
 		unable_to_lock_message(sb.buf, errno, err);
 		strbuf_release(&sb);
 		return -1;
@@ -2535,12 +2530,17 @@ static int files_delete_refs(struct ref_store *ref_store,
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
-static int rename_tmp_log_callback(const char *path, void *cb)
+struct rename_tmp_log_cb {
+	struct files_ref_store *refs;
+	int true_errno;
+};
+
+static int rename_tmp_log_callback(const char *path, void *cb_)
 {
 	struct strbuf sb = STRBUF_INIT;
-	int *true_errno = cb;
+	struct rename_tmp_log_cb *cb = cb_;
 
-	strbuf_git_path(&sb, TMP_RENAMED_LOG);
+	files_path(cb->refs, &sb, TMP_RENAMED_LOG);
 	if (rename(sb.buf, path)) {
 		/*
 		 * rename(a, b) when b is an existing directory ought
@@ -2549,7 +2549,7 @@ static int rename_tmp_log_callback(const char *path, void *cb)
 		 * but report EISDIR to raceproof_create_file() so
 		 * that it knows to retry.
 		 */
-		*true_errno = errno;
+		cb->true_errno = errno;
 		strbuf_release(&sb);
 		if (errno == ENOTDIR)
 			errno = EISDIR;
@@ -2560,25 +2560,27 @@ static int rename_tmp_log_callback(const char *path, void *cb)
 	}
 }
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 {
 	struct strbuf sb = STRBUF_INIT;
+	struct rename_tmp_log_cb cb;
 	const char *path;
-	int ret, true_errno;
+	int ret;
 
-	strbuf_git_path(&sb, "logs/%s", newrefname);
+	files_path(refs, &sb, "logs/%s", newrefname);
 	path = sb.buf;
-	ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
+	cb.refs = refs;
+	ret = raceproof_create_file(path, rename_tmp_log_callback, &cb);
 	if (ret) {
 		if (errno == EISDIR)
 			error("directory not empty: %s", path);
 		else {
 			struct strbuf tmp_renamed = STRBUF_INIT;
 
-			strbuf_git_path(&tmp_renamed, TMP_RENAMED_LOG);
+			files_path(refs, &tmp_renamed, TMP_RENAMED_LOG);
 			error("unable to move logfile %s to %s: %s",
 			      tmp_renamed.buf, path,
-			      strerror(true_errno));
+			      strerror(cb.true_errno));
 			strbuf_release(&tmp_renamed);
 		}
 	}
@@ -2630,7 +2632,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	log = !lstat(sb_oldref.buf, &loginfo);
 	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
@@ -2646,8 +2648,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
 	strbuf_release(&sb_oldref);
 	strbuf_release(&tmp_renamed_log);
@@ -2674,7 +2676,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			struct strbuf path = STRBUF_INIT;
 			int result;
 
-			strbuf_git_path(&path, "%s", newrefname);
+			files_path(refs, &path, "%s", newrefname);
 			result = remove_empty_directories(&path);
 			strbuf_release(&path);
 
@@ -2688,7 +2690,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 		}
 	}
 
-	if (log && rename_tmp_log(newrefname))
+	if (log && rename_tmp_log(refs, newrefname))
 		goto rollback;
 
 	logmoved = log;
@@ -2730,12 +2732,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_path(refs, &sb_newref, "logs/%s", newrefname);
+	files_path(refs, &sb_oldref, "logs/%s", oldrefname);
 	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	files_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
 	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
@@ -2803,10 +2805,15 @@ static int open_or_create_logfile(const char *path, void *cb)
  * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
  * return -1.
  */
-static int log_ref_setup(const char *refname, int force_create,
+static int log_ref_setup(struct files_ref_store *refs,
+			 const char *refname, int force_create,
 			 int *logfd, struct strbuf *err)
 {
-	char *logfile = git_pathdup("logs/%s", refname);
+	struct strbuf sb = STRBUF_INIT;
+	char *logfile;
+
+	files_path(refs, &sb, "logs/%s", refname);
+	logfile = strbuf_detach(&sb, NULL);
 
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
@@ -2856,12 +2863,11 @@ static int files_create_reflog(struct ref_store *ref_store,
 			       const char *refname, int force_create,
 			       struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "create_reflog");
 	int fd;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "create_reflog");
-
-	if (log_ref_setup(refname, force_create, &fd, err))
+	if (log_ref_setup(refs, refname, force_create, &fd, err))
 		return -1;
 
 	if (fd >= 0)
@@ -2896,7 +2902,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	return 0;
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+int files_log_ref_write(struct files_ref_store *refs,
+			const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)
 {
@@ -2905,7 +2912,7 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 	if (log_all_ref_updates == LOG_REFS_UNSET)
 		log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
 
-	result = log_ref_setup(refname, flags & REF_FORCE_CREATE_REFLOG,
+	result = log_ref_setup(refs, refname, flags & REF_FORCE_CREATE_REFLOG,
 			       &logfd, err);
 
 	if (result)
@@ -2919,7 +2926,7 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
-		strbuf_git_path(&sb, "logs/%s", refname);
+		files_path(refs, &sb, "logs/%s", refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
 			    sb.buf, strerror(save_errno));
 		strbuf_release(&sb);
@@ -2930,7 +2937,7 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
-		strbuf_git_path(&sb, "logs/%s", refname);
+		files_path(refs, &sb, "logs/%s", refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
 			    sb.buf, strerror(save_errno));
 		strbuf_release(&sb);
@@ -2991,8 +2998,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (files_log_ref_write(lock->ref_name, lock->old_oid.hash, sha1,
-				logmsg, 0, err)) {
+	if (files_log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
+				sha1, logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
 			    lock->ref_name, old_msg);
@@ -3023,8 +3030,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (files_log_ref_write("HEAD", lock->old_oid.hash, sha1,
-					  logmsg, 0, &log_err)) {
+			if (files_log_ref_write(refs, "HEAD", lock->old_oid.hash,
+						sha1, logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
 			}
@@ -3056,24 +3063,26 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 	return ret;
 }
 
-static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+static void update_symref_reflog(struct files_ref_store *refs,
+				 struct ref_lock *lock, const char *refname,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
 	if (logmsg && !read_ref(target, new_sha1) &&
-	    files_log_ref_write(refname, lock->old_oid.hash, new_sha1,
+	    files_log_ref_write(refs, refname, lock->old_oid.hash, new_sha1,
 				logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
 }
 
-static int create_symref_locked(struct ref_lock *lock, const char *refname,
+static int create_symref_locked(struct files_ref_store *refs,
+				struct ref_lock *lock, const char *refname,
 				const char *target, const char *logmsg)
 {
 	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(lock, refname, target, logmsg);
+		update_symref_reflog(refs, lock, refname, target, logmsg);
 		return 0;
 	}
 
@@ -3081,7 +3090,7 @@ static int create_symref_locked(struct ref_lock *lock, const char *refname,
 		return error("unable to fdopen %s: %s",
 			     lock->lk->tempfile.filename.buf, strerror(errno));
 
-	update_symref_reflog(lock, refname, target, logmsg);
+	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
 	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
@@ -3110,13 +3119,19 @@ static int files_create_symref(struct ref_store *ref_store,
 		return -1;
 	}
 
-	ret = create_symref_locked(lock, refname, target, logmsg);
+	ret = create_symref_locked(refs, lock, refname, target, logmsg);
 	unlock_ref(lock);
 	return ret;
 }
 
 int set_worktree_head_symref(const char *gitdir, const char *target)
 {
+	/*
+	 * FIXME: this obviously will not work well for future refs
+	 * backends. This function needs to die.
+	 */
+	struct files_ref_store *refs =
+		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3143,7 +3158,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	lock->lk = &head_lock;
 	lock->ref_name = xstrdup(head_rel);
 
-	ret = create_symref_locked(lock, head_rel, target, NULL);
+	ret = create_symref_locked(refs, lock, head_rel, target, NULL);
 
 	unlock_ref(lock); /* will free lock */
 	strbuf_release(&head_path);
@@ -3153,14 +3168,13 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_exists");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
 	strbuf_release(&sb);
 	return ret;
@@ -3169,13 +3183,12 @@ static int files_reflog_exists(struct ref_store *ref_store,
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "delete_reflog");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	ret = remove_path(sb.buf);
 	strbuf_release(&sb);
 	return ret;
@@ -3225,15 +3238,14 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     each_reflog_ent_fn fn,
 					     void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
 	int ret = 0, at_tail = 1;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3334,14 +3346,13 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     const char *refname,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3423,15 +3434,14 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_iterator_begin");
-
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	strbuf_git_path(&sb, "logs");
+	files_path(refs, &sb, "logs");
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
 	strbuf_release(&sb);
 	return ref_iterator;
@@ -3856,7 +3866,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (files_log_ref_write(lock->ref_name,
+			if (files_log_ref_write(refs,
+						lock->ref_name,
 						lock->old_oid.hash,
 						update->new_sha1,
 						update->msg, update->flags,
@@ -3894,7 +3905,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 			    update->type & REF_ISSYMREF) {
 				/* It is a loose reference. */
 				strbuf_reset(&sb);
-				strbuf_git_path(&sb, "%s", lock->ref_name);
+				files_path(refs, &sb, "%s", lock->ref_name);
 				if (unlink_or_msg(sb.buf, err)) {
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto cleanup;
@@ -3917,9 +3928,10 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
 		struct strbuf sb = STRBUF_INIT;
 
-		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		files_path(refs, &sb, "logs/%s", ref_to_delete->string);
 		if (!unlink_or_warn(sb.buf))
-			try_remove_empty_parents(ref_to_delete->string,
+			try_remove_empty_parents(refs,
+						 ref_to_delete->string,
 						 REMOVE_EMPTY_PARENTS_REFLOG);
 		strbuf_release(&sb);
 	}
@@ -3943,7 +3955,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 			 * can only work because we have already
 			 * removed the lockfile.)
 			 */
-			try_remove_empty_parents(update->refname,
+			try_remove_empty_parents(refs,
+						 update->refname,
 						 REMOVE_EMPTY_PARENTS_REF);
 		}
 	}
@@ -4098,6 +4111,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	int status = 0;
 	int type;
 	struct strbuf err = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 
 	memset(&cb, 0, sizeof(cb));
 	cb.flags = flags;
@@ -4122,7 +4136,8 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		return 0;
 	}
 
-	log_file = git_pathdup("logs/%s", refname);
+	files_path(refs, &sb, "logs/%s", refname);
+	log_file = strbuf_detach(&sb, NULL);
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 		/*
 		 * Even though holding $GIT_DIR/logs/$reflog.lock has
@@ -4193,25 +4208,24 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "init_db");
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	strbuf_git_path(&sb, "refs/heads");
+	files_path(refs, &sb, "refs/heads");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
-	strbuf_git_path(&sb, "refs/tags");
+	files_path(refs, &sb, "refs/tags");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		strbuf_git_path(&sb, "refs/heads");
+		files_path(refs, &sb, "refs/heads");
 		adjust_shared_perm(sb.buf);
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "refs/tags");
+		files_path(refs, &sb, "refs/tags");
 		adjust_shared_perm(sb.buf);
 	}
 	strbuf_release(&sb);
-- 
2.11.0.157.gd943d85

[PATCH v4 05/15] refs.c: share is_per_worktree_ref() to files-backend.c

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 6 ------
 refs/refs-internal.h | 6 ++++++
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/refs.c b/refs.c
index 81b64b4ed..c6af84357 100644
--- a/refs.c
+++ b/refs.c
@@ -489,12 +489,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-static int is_per_worktree_ref(const char *refname)
-{
-	return !strcmp(refname, "HEAD") ||
-		starts_with(refname, "refs/bisect/");
-}
-
 static int is_pseudoref_syntax(const char *refname)
 {
 	const char *c;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index f732473e1..8c5febf54 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -657,4 +657,10 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 				    int resolve_flags,
 				    unsigned char *sha1, int *flags);
 
+static inline int is_per_worktree_ref(const char *refname)
+{
+	return !strcmp(refname, "HEAD") ||
+		starts_with(refname, "refs/bisect/");
+}
+
 #endif /* REFS_REFS_INTERNAL_H */
-- 
2.11.0.157.gd943d85

[PATCH v4 06/15] files-backend: remove the use of git_path()

[Nguyễn Thái Ngọc Duy]

Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
deciding what goes where. The end goal is to pass $GIT_DIR only. A
refs "view" of a linked worktree is a logical ref store that combines
two files backends together.

(*) Not entirely true since strbuf_git_path_submodule() still does path
translation underneath. But that's for another patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index b599ddf92..dbcaf9bda 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -924,6 +924,9 @@ struct files_ref_store {
 	 */
 	const char *submodule;
 
+	struct strbuf gitdir;
+	struct strbuf gitcommondir;
+
 	struct ref_entry *loose;
 	struct packed_ref_cache *packed;
 };
@@ -937,15 +940,33 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 {
 	struct strbuf tmp = STRBUF_INIT;
 	va_list vap;
+	const char *ref;
 
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
 	va_end(vap);
-	if (refs->submodule)
+	if (refs->submodule) {
 		strbuf_git_path_submodule(sb, refs->submodule,
 					  "%s", tmp.buf);
-	else
-		strbuf_git_path(sb, "%s", tmp.buf);
+	} else if (!strcmp(tmp.buf, "packed-refs") ||
+		   !strcmp(tmp.buf, "logs")) { /* non refname path */
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
+	} else if (skip_prefix(tmp.buf, "logs/", &ref)) { /* reflog */
+		if (is_per_worktree_ref(ref))
+			strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
+		else
+			strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
+	} else {		/* refname */
+		switch (ref_type(tmp.buf)) {
+		case REF_TYPE_PER_WORKTREE:
+		case REF_TYPE_PSEUDOREF:
+			strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
+			break;
+		case REF_TYPE_NORMAL:
+			strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
+			break;
+		}
+	}
 	strbuf_release(&tmp);
 }
 
@@ -1004,7 +1025,15 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
-	refs->submodule = xstrdup_or_null(submodule);
+	strbuf_init(&refs->gitdir, 0);
+	strbuf_init(&refs->gitcommondir, 0);
+
+	if (submodule) {
+		refs->submodule = xstrdup(submodule);
+	} else {
+		strbuf_addstr(&refs->gitdir, get_git_dir());
+		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
+	}
 
 	return ref_store;
 }
-- 
2.11.0.157.gd943d85

Re: [PATCH v4 06/15] files-backend: remove the use of git_path()

[Michael Haggerty]

On 02/18/2017 02:32 PM, Nguyễn Thái Ngọc Duy wrote:
> Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
> deciding what goes where. The end goal is to pass $GIT_DIR only. A
> refs "view" of a linked worktree is a logical ref store that combines
> two files backends together.
> 
> (*) Not entirely true since strbuf_git_path_submodule() still does path
> translation underneath. But that's for another patch.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 37 +++++++++++++++++++++++++++++++++----
>  1 file changed, 33 insertions(+), 4 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index b599ddf92..dbcaf9bda 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -924,6 +924,9 @@ struct files_ref_store {
>  	 */
>  	const char *submodule;
>  
> +	struct strbuf gitdir;
> +	struct strbuf gitcommondir;

Is there a reason for these to be `strbuf`s rather than `const char *`?
(One reason would be if you planned to use the `len` field, but I don't
think you do so.)

> @@ -937,15 +940,33 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
>  {
>  	struct strbuf tmp = STRBUF_INIT;
>  	va_list vap;
> +	const char *ref;
>  
>  	va_start(vap, fmt);
>  	strbuf_vaddf(&tmp, fmt, vap);
>  	va_end(vap);
> -	if (refs->submodule)
> +	if (refs->submodule) {
>  		strbuf_git_path_submodule(sb, refs->submodule,
>  					  "%s", tmp.buf);
> -	else
> -		strbuf_git_path(sb, "%s", tmp.buf);
> +	} else if (!strcmp(tmp.buf, "packed-refs") ||
> +		   !strcmp(tmp.buf, "logs")) { /* non refname path */
> +		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
> +	} else if (skip_prefix(tmp.buf, "logs/", &ref)) { /* reflog */
> +		if (is_per_worktree_ref(ref))
> +			strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
> +		else
> +			strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);

This code would also be simpler if there were separate functions for
packed-refs, loose references, and reflogs.

> [...]

Michael

Re: [PATCH v4 06/15] files-backend: remove the use of git_path()

[Duy Nguyen]

On Mon, Feb 20, 2017 at 6:34 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/18/2017 02:32 PM, Nguyễn Thái Ngọc Duy wrote:
>> Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
>> deciding what goes where. The end goal is to pass $GIT_DIR only. A
>> refs "view" of a linked worktree is a logical ref store that combines
>> two files backends together.
>>
>> (*) Not entirely true since strbuf_git_path_submodule() still does path
>> translation underneath. But that's for another patch.
>>
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>>  refs/files-backend.c | 37 +++++++++++++++++++++++++++++++++----
>>  1 file changed, 33 insertions(+), 4 deletions(-)
>>
>> diff --git a/refs/files-backend.c b/refs/files-backend.c
>> index b599ddf92..dbcaf9bda 100644
>> --- a/refs/files-backend.c
>> +++ b/refs/files-backend.c
>> @@ -924,6 +924,9 @@ struct files_ref_store {
>>        */
>>       const char *submodule;
>>
>> +     struct strbuf gitdir;
>> +     struct strbuf gitcommondir;
>
> Is there a reason for these to be `strbuf`s rather than `const char *`?
> (One reason would be if you planned to use the `len` field, but I don't
> think you do so.)

Nope. I just didn't think about char *. It may have to lose "const"
though because in submodule case we may need a new allocation.

>
>> @@ -937,15 +940,33 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
>>  {
>>       struct strbuf tmp = STRBUF_INIT;
>>       va_list vap;
>> +     const char *ref;
>>
>>       va_start(vap, fmt);
>>       strbuf_vaddf(&tmp, fmt, vap);
>>       va_end(vap);
>> -     if (refs->submodule)
>> +     if (refs->submodule) {
>>               strbuf_git_path_submodule(sb, refs->submodule,
>>                                         "%s", tmp.buf);
>> -     else
>> -             strbuf_git_path(sb, "%s", tmp.buf);
>> +     } else if (!strcmp(tmp.buf, "packed-refs") ||
>> +                !strcmp(tmp.buf, "logs")) { /* non refname path */
>> +             strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
>> +     } else if (skip_prefix(tmp.buf, "logs/", &ref)) { /* reflog */
>> +             if (is_per_worktree_ref(ref))
>> +                     strbuf_addf(sb, "%s/%s", refs->gitdir.buf, tmp.buf);
>> +             else
>> +                     strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
>
> This code would also be simpler if there were separate functions for
> packed-refs, loose references, and reflogs.

And maybe keep the path to packed-refs, the base path up to "logs" in
struct files_ref_store too (they will be calculated at ref store
init)? That way the files_packed_refs_path() does no calculation.
files_reflog_path() and files_ref_path() will just do string
concatenation, no fancy addf.
-- 
Duy

[PATCH v4 07/15] refs.c: introduce get_main_ref_store()

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/refs.c b/refs.c
index c6af84357..c3bdc99d8 100644
--- a/refs.c
+++ b/refs.c
@@ -1450,15 +1450,23 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
+static struct ref_store *get_main_ref_store(void)
+{
+	struct ref_store *refs;
+
+	if (main_ref_store)
+		return main_ref_store;
+
+	refs = ref_store_init(NULL);
+	return refs;
+}
+
 struct ref_store *get_ref_store(const char *submodule)
 {
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
-		refs = lookup_ref_store(NULL);
-
-		if (!refs)
-			refs = ref_store_init(NULL);
+		return get_main_ref_store();
 	} else {
 		refs = lookup_ref_store(submodule);
 
-- 
2.11.0.157.gd943d85

[PATCH v4 08/15] refs: rename lookup_ref_store() to lookup_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

With get_main_ref_store() being used inside get_ref_store(),
lookup_ref_store() is only used for submodule code path. Rename to
reflect that and delete dead code.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index c3bdc99d8..6aab5e4ac 100644
--- a/refs.c
+++ b/refs.c
@@ -1389,17 +1389,13 @@ static struct ref_store *main_ref_store;
 static struct hashmap submodule_ref_stores;
 
 /*
- * Return the ref_store instance for the specified submodule (or the
- * main repository if submodule is NULL). If that ref_store hasn't
- * been initialized yet, return NULL.
+ * Return the ref_store instance for the specified submodule. If that
+ * ref_store hasn't been initialized yet, return NULL.
  */
-static struct ref_store *lookup_ref_store(const char *submodule)
+static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 {
 	struct submodule_hash_entry *entry;
 
-	if (!submodule)
-		return main_ref_store;
-
 	if (!submodule_ref_stores.tablesize)
 		/* It's initialized on demand in register_ref_store(). */
 		return NULL;
@@ -1468,7 +1464,7 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
 	} else {
-		refs = lookup_ref_store(submodule);
+		refs = lookup_submodule_ref_store(submodule);
 
 		if (!refs) {
 			struct strbuf submodule_sb = STRBUF_INIT;
@@ -1479,7 +1475,6 @@ struct ref_store *get_ref_store(const char *submodule)
 			strbuf_release(&submodule_sb);
 		}
 	}
-
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v4 09/15] refs.c: flatten get_ref_store() a bit

[Nguyễn Thái Ngọc Duy]

This helps the future changes in this code. And because get_ref_store()
is destined to become get_submodule_ref_store(), the "get main store"
code path will be removed eventually. After this the patch to delete
that code will be cleaner.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/refs.c b/refs.c
index 6aab5e4ac..549eeccb4 100644
--- a/refs.c
+++ b/refs.c
@@ -1459,22 +1459,21 @@ static struct ref_store *get_main_ref_store(void)
 
 struct ref_store *get_ref_store(const char *submodule)
 {
+	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
-	} else {
-		refs = lookup_submodule_ref_store(submodule);
+	}
 
-		if (!refs) {
-			struct strbuf submodule_sb = STRBUF_INIT;
+	refs = lookup_submodule_ref_store(submodule);
+	if (refs)
+		return refs;
 
-			strbuf_addstr(&submodule_sb, submodule);
-			if (is_nonbare_repository_dir(&submodule_sb))
-				refs = ref_store_init(submodule);
-			strbuf_release(&submodule_sb);
-		}
-	}
+	strbuf_addstr(&submodule_sb, submodule);
+	if (is_nonbare_repository_dir(&submodule_sb))
+		refs = ref_store_init(submodule);
+	strbuf_release(&submodule_sb);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v4 10/15] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

This is the last function in this code (besides public API) that takes
submodule argument and handles both main/submodule cases. Break it down,
move main store registration in get_main_ref_store() and keep the rest
in register_submodule_ref_store().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/refs.c b/refs.c
index 549eeccb4..8b640bd05 100644
--- a/refs.c
+++ b/refs.c
@@ -1407,25 +1407,19 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 
 /*
  * Register the specified ref_store to be the one that should be used
- * for submodule (or the main repository if submodule is NULL). It is
- * a fatal error to call this function twice for the same submodule.
+ * for submodule. It is a fatal error to call this function twice for
+ * the same submodule.
  */
-static void register_ref_store(struct ref_store *refs, const char *submodule)
+static void register_submodule_ref_store(struct ref_store *refs,
+					 const char *submodule)
 {
-	if (!submodule) {
-		if (main_ref_store)
-			die("BUG: main_ref_store initialized twice");
-
-		main_ref_store = refs;
-	} else {
-		if (!submodule_ref_stores.tablesize)
-			hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
+	if (!submodule_ref_stores.tablesize)
+		hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
 
-		if (hashmap_put(&submodule_ref_stores,
-				alloc_submodule_hash_entry(submodule, refs)))
-			die("BUG: ref_store for submodule '%s' initialized twice",
-			    submodule);
-	}
+	if (hashmap_put(&submodule_ref_stores,
+			alloc_submodule_hash_entry(submodule, refs)))
+		die("BUG: ref_store for submodule '%s' initialized twice",
+		    submodule);
 }
 
 /*
@@ -1442,7 +1436,6 @@ static struct ref_store *ref_store_init(const char *submodule)
 		die("BUG: reference backend %s is unknown", be_name);
 
 	refs = be->init(submodule);
-	register_ref_store(refs, submodule);
 	return refs;
 }
 
@@ -1454,6 +1447,12 @@ static struct ref_store *get_main_ref_store(void)
 		return main_ref_store;
 
 	refs = ref_store_init(NULL);
+	if (refs) {
+		if (main_ref_store)
+			die("BUG: main_ref_store initialized twice");
+
+		main_ref_store = refs;
+	}
 	return refs;
 }
 
@@ -1474,6 +1473,9 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (is_nonbare_repository_dir(&submodule_sb))
 		refs = ref_store_init(submodule);
 	strbuf_release(&submodule_sb);
+
+	if (refs)
+		register_submodule_ref_store(refs, submodule);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v4 11/15] refs.c: make get_main_ref_store() public and use it

[Nguyễn Thái Ngọc Duy]

get_ref_store() will soon be renamed to get_submodule_ref_store().
Together with future get_worktree_ref_store(), the three functions
provide an appropriate ref store for different operation modes. New APIs
will be added to operate directly on ref stores.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 36 ++++++++++++++++++------------------
 refs.h |  2 ++
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/refs.c b/refs.c
index 8b640bd05..1b60e6180 100644
--- a/refs.c
+++ b/refs.c
@@ -1308,7 +1308,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->init_db(refs, err);
 }
@@ -1316,7 +1316,7 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_ref_store(NULL), refname,
+	return resolve_ref_recursively(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1439,7 +1439,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
-static struct ref_store *get_main_ref_store(void)
+struct ref_store *get_main_ref_store(void)
 {
 	struct ref_store *refs;
 
@@ -1488,14 +1488,14 @@ void base_ref_store_init(struct ref_store *refs,
 /* backend functions */
 int pack_refs(unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->pack_refs(refs, flags);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->peel_ref(refs, refname, sha1);
 }
@@ -1503,7 +1503,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_symref(refs, ref_target, refs_heads_master,
 				       logmsg);
@@ -1512,7 +1512,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1522,14 +1522,14 @@ int verify_refname_available(const char *refname,
 			     const struct string_list *skip,
 			     struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
 }
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1540,7 +1540,7 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent_reverse(refs, refname,
 						     fn, cb_data);
@@ -1549,14 +1549,14 @@ int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_exists(refs, refname);
 }
@@ -1564,14 +1564,14 @@ int reflog_exists(const char *refname)
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_reflog(refs, refname);
 }
@@ -1583,7 +1583,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_expire(refs, refname, sha1, flags,
 				       prepare_fn, should_prune_fn,
@@ -1593,21 +1593,21 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
 int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_refs(refs, refnames, flags);
 }
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index 9fbff90e7..a35b687d7 100644
--- a/refs.h
+++ b/refs.h
@@ -555,4 +555,6 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 
 int ref_storage_backend_exists(const char *name);
 
+struct ref_store *get_main_ref_store(void);
+
 #endif /* REFS_H */
-- 
2.11.0.157.gd943d85

Re: [PATCH v4 11/15] refs.c: make get_main_ref_store() public and use it

[Michael Haggerty]

On 02/18/2017 02:32 PM, Nguyễn Thái Ngọc Duy wrote:
> get_ref_store() will soon be renamed to get_submodule_ref_store().
> Together with future get_worktree_ref_store(), the three functions
> provide an appropriate ref store for different operation modes. New APIs
> will be added to operate directly on ref stores.

I see where you're going with this, but as of the end of this patch
series, there is still nothing that a caller outside of the refs module
can do with a `struct ref_store *`. This means that it would be enough
to put this declaration (and that of `get_submodule_ref_store()`, added
in a later patch) in refs/refs-internal.h for now.

If you want to move the declarations straight to `refs.h` now to avoid
code churn in some later patch series, then please mention that fact in
the commit message.

Michael

[PATCH v4 12/15] path.c: move some code out of strbuf_git_path_submodule()

[Nguyễn Thái Ngọc Duy]

refs is learning to avoid path rewriting that is done by
strbuf_git_path_submodule(). Factor out this code so it could be reused
by refs*

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 path.c      | 34 +++++++---------------------------
 submodule.c | 31 +++++++++++++++++++++++++++++++
 submodule.h |  1 +
 3 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/path.c b/path.c
index efcedafba..3451d2916 100644
--- a/path.c
+++ b/path.c
@@ -475,35 +475,16 @@ const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 static int do_submodule_path(struct strbuf *buf, const char *path,
 			     const char *fmt, va_list args)
 {
-	const char *git_dir;
 	struct strbuf git_submodule_common_dir = STRBUF_INIT;
 	struct strbuf git_submodule_dir = STRBUF_INIT;
-	const struct submodule *sub;
-	int err = 0;
+	int ret;
 
-	strbuf_addstr(buf, path);
-	strbuf_complete(buf, '/');
-	strbuf_addstr(buf, ".git");
-
-	git_dir = read_gitfile(buf->buf);
-	if (git_dir) {
-		strbuf_reset(buf);
-		strbuf_addstr(buf, git_dir);
-	}
-	if (!is_git_directory(buf->buf)) {
-		gitmodules_config();
-		sub = submodule_from_path(null_sha1, path);
-		if (!sub) {
-			err = SUBMODULE_PATH_ERR_NOT_CONFIGURED;
-			goto cleanup;
-		}
-		strbuf_reset(buf);
-		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
-	}
-
-	strbuf_addch(buf, '/');
-	strbuf_addbuf(&git_submodule_dir, buf);
+	ret = submodule_to_gitdir(&git_submodule_dir, path);
+	if (ret)
+		goto cleanup;
 
+	strbuf_complete(&git_submodule_dir, '/');
+	strbuf_addbuf(buf, &git_submodule_dir);
 	strbuf_vaddf(buf, fmt, args);
 
 	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
@@ -514,8 +495,7 @@ static int do_submodule_path(struct strbuf *buf, const char *path,
 cleanup:
 	strbuf_release(&git_submodule_dir);
 	strbuf_release(&git_submodule_common_dir);
-
-	return err;
+	return ret;
 }
 
 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
diff --git a/submodule.c b/submodule.c
index 3b98766a6..36b8d1d11 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1514,3 +1514,34 @@ void absorb_git_dir_into_superproject(const char *prefix,
 		strbuf_release(&sb);
 	}
 }
+
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
+{
+	const struct submodule *sub;
+	const char *git_dir;
+	int ret = 0;
+
+	strbuf_reset(buf);
+	strbuf_addstr(buf, submodule);
+	strbuf_complete(buf, '/');
+	strbuf_addstr(buf, ".git");
+
+	git_dir = read_gitfile(buf->buf);
+	if (git_dir) {
+		strbuf_reset(buf);
+		strbuf_addstr(buf, git_dir);
+	}
+	if (!is_git_directory(buf->buf)) {
+		gitmodules_config();
+		sub = submodule_from_path(null_sha1, submodule);
+		if (!sub) {
+			ret = -1;
+			goto cleanup;
+		}
+		strbuf_reset(buf);
+		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
+	}
+
+cleanup:
+	return ret;
+}
diff --git a/submodule.h b/submodule.h
index 05ab674f0..fc3d0303e 100644
--- a/submodule.h
+++ b/submodule.h
@@ -81,6 +81,7 @@ extern int push_unpushed_submodules(struct sha1_array *commits,
 				    int dry_run);
 extern void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
 extern int parallel_submodules(void);
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 /*
  * Prepare the "env_array" parameter of a "struct child_process" for executing
-- 
2.11.0.157.gd943d85

[PATCH v4 13/15] refs: move submodule code out of files-backend.c

[Nguyễn Thái Ngọc Duy]

files-backend is now initialized with a $GIT_DIR. Converting a submodule
path to where real submodule gitdir is located is done in get_ref_store().

The new code in init_submodule_ref_store() is basically a copy of
strbuf_git_path_submodule().

This gives a slight performance improvement for submodules since we
don't convert submodule path to gitdir at every backend call like
before. We pay that once at ref-store creation.

More cleanup in files_downcast() follows shortly. It's separate to keep
noises from this patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 18 +++++++++++++-----
 refs/files-backend.c | 24 +++++++-----------------
 refs/refs-internal.h |  6 +++---
 3 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/refs.c b/refs.c
index 1b60e6180..8035c3ea7 100644
--- a/refs.c
+++ b/refs.c
@@ -9,6 +9,7 @@
 #include "refs/refs-internal.h"
 #include "object.h"
 #include "tag.h"
+#include "submodule.h"
 
 /*
  * List of all available backends
@@ -1424,9 +1425,9 @@ static void register_submodule_ref_store(struct ref_store *refs,
 
 /*
  * Create, record, and return a ref_store instance for the specified
- * submodule (or the main repository if submodule is NULL).
+ * gitdir (or the main repository if gitdir is NULL).
  */
-static struct ref_store *ref_store_init(const char *submodule)
+static struct ref_store *ref_store_init(const char *gitdir)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1435,7 +1436,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(submodule);
+	refs = be->init(gitdir);
 	return refs;
 }
 
@@ -1460,6 +1461,7 @@ struct ref_store *get_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
+	int ret;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
@@ -1470,8 +1472,14 @@ struct ref_store *get_ref_store(const char *submodule)
 		return refs;
 
 	strbuf_addstr(&submodule_sb, submodule);
-	if (is_nonbare_repository_dir(&submodule_sb))
-		refs = ref_store_init(submodule);
+	ret = is_nonbare_repository_dir(&submodule_sb);
+	strbuf_release(&submodule_sb);
+	if (!ret)
+		return refs;
+
+	ret = submodule_to_gitdir(&submodule_sb, submodule);
+	if (!ret)
+		refs = ref_store_init(submodule_sb.buf);
 	strbuf_release(&submodule_sb);
 
 	if (refs)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index dbcaf9bda..529c80af1 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -917,13 +917,6 @@ struct packed_ref_cache {
 struct files_ref_store {
 	struct ref_store base;
 
-	/*
-	 * The name of the submodule represented by this object, or
-	 * NULL if it represents the main repository's reference
-	 * store:
-	 */
-	const char *submodule;
-
 	struct strbuf gitdir;
 	struct strbuf gitcommondir;
 
@@ -945,11 +938,8 @@ static void files_path(struct files_ref_store *refs, struct strbuf *sb,
 	va_start(vap, fmt);
 	strbuf_vaddf(&tmp, fmt, vap);
 	va_end(vap);
-	if (refs->submodule) {
-		strbuf_git_path_submodule(sb, refs->submodule,
-					  "%s", tmp.buf);
-	} else if (!strcmp(tmp.buf, "packed-refs") ||
-		   !strcmp(tmp.buf, "logs")) { /* non refname path */
+	if (!strcmp(tmp.buf, "packed-refs") || !strcmp(tmp.buf, "logs")) {
+		/* non refname path */
 		strbuf_addf(sb, "%s/%s", refs->gitcommondir.buf, tmp.buf);
 	} else if (skip_prefix(tmp.buf, "logs/", &ref)) { /* reflog */
 		if (is_per_worktree_ref(ref))
@@ -1018,7 +1008,7 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *submodule)
+static struct ref_store *files_ref_store_create(const char *gitdir)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
@@ -1028,8 +1018,9 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 	strbuf_init(&refs->gitdir, 0);
 	strbuf_init(&refs->gitcommondir, 0);
 
-	if (submodule) {
-		refs->submodule = xstrdup(submodule);
+	if (gitdir) {
+		strbuf_addstr(&refs->gitdir, gitdir);
+		get_common_dir_noenv(&refs->gitcommondir, gitdir);
 	} else {
 		strbuf_addstr(&refs->gitdir, get_git_dir());
 		strbuf_addstr(&refs->gitcommondir, get_git_common_dir());
@@ -1045,8 +1036,7 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	if (refs->submodule)
-		die("BUG: %s called for a submodule", caller);
+	/* This function is to be deleted in the next patch */
 }
 
 /*
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 8c5febf54..3ef020acf 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -482,12 +482,12 @@ struct ref_store;
 /* refs backends */
 
 /*
- * Initialize the ref_store for the specified submodule, or for the
- * main repository if submodule == NULL. These functions should call
+ * Initialize the ref_store for the specified gitdir, or for the
+ * current repository if gitdir == NULL. These functions should call
  * base_ref_store_init() to initialize the shared part of the
  * ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *submodule);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
-- 
2.11.0.157.gd943d85

[PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Nguyễn Thái Ngọc Duy]

Since submodule or not is irrelevant to files-backend after the last
patch, remove the parameter from files_downcast() and kill
files_assert_main_repository().

PS. This implies that all ref operations are allowed for submodules. But
we may need to look more closely to see if that's really true...

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 70 ++++++++++++++++------------------------------------
 1 file changed, 21 insertions(+), 49 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 529c80af1..b8ccf4e47 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1030,24 +1030,13 @@ static struct ref_store *files_ref_store_create(const char *gitdir)
 }
 
 /*
- * Die if refs is for a submodule (i.e., not for the main repository).
- * caller is used in any necessary error messages.
- */
-static void files_assert_main_repository(struct files_ref_store *refs,
-					 const char *caller)
-{
-	/* This function is to be deleted in the next patch */
-}
-
-/*
  * Downcast ref_store to files_ref_store. Die if ref_store is not a
  * files_ref_store. If submodule_allowed is not true, then also die if
  * files_ref_store is for a submodule (i.e., not for the main
  * repository). caller is used in any necessary error messages.
  */
-static struct files_ref_store *files_downcast(
-		struct ref_store *ref_store, int submodule_allowed,
-		const char *caller)
+static struct files_ref_store *files_downcast(struct ref_store *ref_store,
+					      const char *caller)
 {
 	struct files_ref_store *refs;
 
@@ -1057,9 +1046,6 @@ static struct files_ref_store *files_downcast(
 
 	refs = (struct files_ref_store *)ref_store;
 
-	if (!submodule_allowed)
-		files_assert_main_repository(refs, caller);
-
 	return refs;
 }
 
@@ -1395,7 +1381,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "read_raw_ref");
+		files_downcast(ref_store, "read_raw_ref");
 	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
@@ -1588,7 +1574,6 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	int ret = TRANSACTION_GENERIC_ERROR;
 
 	assert(err);
-	files_assert_main_repository(refs, "lock_raw_ref");
 
 	*type = 0;
 
@@ -1812,7 +1797,7 @@ static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
 static int files_peel_ref(struct ref_store *ref_store,
 			  const char *refname, unsigned char *sha1)
 {
-	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
+	struct files_ref_store *refs = files_downcast(ref_store, "peel_ref");
 	int flag;
 	unsigned char base[20];
 
@@ -1921,7 +1906,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 		const char *prefix, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "ref_iterator_begin");
+		files_downcast(ref_store, "ref_iterator_begin");
 	struct ref_dir *loose_dir, *packed_dir;
 	struct ref_iterator *loose_iter, *packed_iter;
 	struct files_ref_iterator *iter;
@@ -2059,7 +2044,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	int resolve_flags = RESOLVE_REF_NO_RECURSE;
 	int resolved;
 
-	files_assert_main_repository(refs, "lock_ref_sha1_basic");
 	assert(err);
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
@@ -2184,8 +2168,6 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	files_assert_main_repository(refs, "lock_packed_refs");
-
 	if (!timeout_configured) {
 		git_config_get_int("core.packedrefstimeout", &timeout_value);
 		timeout_configured = 1;
@@ -2225,8 +2207,6 @@ static int commit_packed_refs(struct files_ref_store *refs)
 	int save_errno = 0;
 	FILE *out;
 
-	files_assert_main_repository(refs, "commit_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 
@@ -2258,8 +2238,6 @@ static void rollback_packed_refs(struct files_ref_store *refs)
 	struct packed_ref_cache *packed_ref_cache =
 		get_packed_ref_cache(refs);
 
-	files_assert_main_repository(refs, "rollback_packed_refs");
-
 	if (!packed_ref_cache->lock)
 		die("internal error: packed-refs not locked");
 	rollback_lock_file(packed_ref_cache->lock);
@@ -2420,7 +2398,7 @@ static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "pack_refs");
+		files_downcast(ref_store, "pack_refs");
 	struct pack_refs_cb_data cbdata;
 
 	memset(&cbdata, 0, sizeof(cbdata));
@@ -2453,7 +2431,6 @@ static int repack_without_refs(struct files_ref_store *refs,
 	struct string_list_item *refname;
 	int ret, needs_repacking = 0, removed = 0;
 
-	files_assert_main_repository(refs, "repack_without_refs");
 	assert(err);
 
 	/* Look for a packed ref */
@@ -2503,7 +2480,7 @@ static int files_delete_refs(struct ref_store *ref_store,
 			     struct string_list *refnames, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_refs");
+		files_downcast(ref_store, "delete_refs");
 	struct strbuf err = STRBUF_INIT;
 	int i, result = 0;
 
@@ -2615,7 +2592,7 @@ static int files_verify_refname_available(struct ref_store *ref_store,
 					  struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "verify_refname_available");
+		files_downcast(ref_store, "verify_refname_available");
 	struct ref_dir *packed_refs = get_packed_refs(refs);
 	struct ref_dir *loose_refs = get_loose_refs(refs);
 
@@ -2640,7 +2617,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			    const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "rename_ref");
+		files_downcast(ref_store, "rename_ref");
 	unsigned char sha1[20], orig_sha1[20];
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
@@ -2883,7 +2860,7 @@ static int files_create_reflog(struct ref_store *ref_store,
 			       struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_reflog");
+		files_downcast(ref_store, "create_reflog");
 	int fd;
 
 	if (log_ref_setup(refs, refname, force_create, &fd, err))
@@ -3014,8 +2991,6 @@ static int commit_ref_update(struct files_ref_store *refs,
 			     const unsigned char *sha1, const char *logmsg,
 			     struct strbuf *err)
 {
-	files_assert_main_repository(refs, "commit_ref_update");
-
 	clear_loose_ref_cache(refs);
 	if (files_log_ref_write(refs, lock->ref_name, lock->old_oid.hash,
 				sha1, logmsg, 0, err)) {
@@ -3124,7 +3099,7 @@ static int files_create_symref(struct ref_store *ref_store,
 			       const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_symref");
+		files_downcast(ref_store, "create_symref");
 	struct strbuf err = STRBUF_INIT;
 	struct ref_lock *lock;
 	int ret;
@@ -3150,7 +3125,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
+		files_downcast(get_ref_store(NULL), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3188,7 +3163,7 @@ static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_exists");
+		files_downcast(ref_store, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
@@ -3203,7 +3178,7 @@ static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_reflog");
+		files_downcast(ref_store, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
@@ -3258,7 +3233,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
+		files_downcast(ref_store, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
@@ -3366,7 +3341,7 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent");
+		files_downcast(ref_store, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
@@ -3454,7 +3429,7 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_iterator_begin");
+		files_downcast(ref_store, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
@@ -3666,8 +3641,6 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 	int ret;
 	struct ref_lock *lock;
 
-	files_assert_main_repository(refs, "lock_ref_for_update");
-
 	if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
 		update->flags |= REF_DELETING;
 
@@ -3792,7 +3765,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 				    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "ref_transaction_commit");
+		files_downcast(ref_store, "ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
@@ -4000,7 +3973,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 					    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "initial_ref_transaction_commit");
+		files_downcast(ref_store, "initial_ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
@@ -4122,7 +4095,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			       void *policy_cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_expire");
+		files_downcast(ref_store, "reflog_expire");
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
@@ -4227,8 +4200,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "init_db");
+	struct files_ref_store *refs = files_downcast(ref_store, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
 	/*
-- 
2.11.0.157.gd943d85

Re: [PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Michael Haggerty]

On 02/18/2017 02:33 PM, Nguyễn Thái Ngọc Duy wrote:
> Since submodule or not is irrelevant to files-backend after the last
> patch, remove the parameter from files_downcast() and kill
> files_assert_main_repository().
> 
> PS. This implies that all ref operations are allowed for submodules. But
> we may need to look more closely to see if that's really true...

I think you are jumping the gun here.

Even after your changes, there is still a significant difference between
the main repository and submodules: we have access to the object
database for the main repository, but not for submodules.

So, for example, the following don't work for submodules:

* `parse_object()` is used to ensure that references are only pointed at
valid objects, and that branches are only pointed at commit objects.

* `peel_object()` is used to write the peeled version of references in
`packed-refs`, and to peel references while they are being iterated
over. Since this doesn't work, I think you can't write `packed-refs` in
a submodule.

These limitations, I think, imply that submodule references have to be
treated as read-only.

When I was working on a patch series similar to yours, I introduced a
boolean "main_repository" flag in `struct ref_store`, and use that
member to implement `files_assert_main_repository()`. That way
`files_ref_store::submodule` can still be removed, which is the more
important goal from a design standpoint.

Michael

Re: [PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Duy Nguyen]

On Mon, Feb 20, 2017 at 7:11 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/18/2017 02:33 PM, Nguyễn Thái Ngọc Duy wrote:
>> Since submodule or not is irrelevant to files-backend after the last
>> patch, remove the parameter from files_downcast() and kill
>> files_assert_main_repository().
>>
>> PS. This implies that all ref operations are allowed for submodules. But
>> we may need to look more closely to see if that's really true...
>
> I think you are jumping the gun here.
>
> Even after your changes, there is still a significant difference between
> the main repository and submodules: we have access to the object
> database for the main repository, but not for submodules.
>
> So, for example, the following don't work for submodules:
>
> * `parse_object()` is used to ensure that references are only pointed at
> valid objects, and that branches are only pointed at commit objects.
>
> * `peel_object()` is used to write the peeled version of references in
> `packed-refs`, and to peel references while they are being iterated
> over. Since this doesn't work, I think you can't write `packed-refs` in
> a submodule.
>
> These limitations, I think, imply that submodule references have to be
> treated as read-only.

Behind the scene submodule does add_submodule_odb(), which basically
makes the submodule's odb an alternate of in-core odb. So odb access
works. I was puzzled how submodules could by pass odb access at the
beginning only to find that out. technical/api-ref-iteration.txt also
mentions that you need to add_submodule_odb(), so I think it's
deliberate (albeit hacky) design.

> When I was working on a patch series similar to yours, I introduced a
> boolean "main_repository" flag in `struct ref_store`, and use that
> member to implement `files_assert_main_repository()`. That way
> `files_ref_store::submodule` can still be removed, which is the more
> important goal from a design standpoint.

I could keep the submodule check back (and replace the submodule
string in files_ref_store with just a flag). But I really think all
backend functions work with submodule. Perhaps add some tests to
exercise/verify that files-backend-on-submodule works?
-- 
Duy

Re: [PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Michael Haggerty]

On 02/20/2017 01:21 PM, Duy Nguyen wrote:
> On Mon, Feb 20, 2017 at 7:11 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>> On 02/18/2017 02:33 PM, Nguyễn Thái Ngọc Duy wrote:
>>> Since submodule or not is irrelevant to files-backend after the last
>>> patch, remove the parameter from files_downcast() and kill
>>> files_assert_main_repository().
>>>
>>> PS. This implies that all ref operations are allowed for submodules. But
>>> we may need to look more closely to see if that's really true...
>>
>> I think you are jumping the gun here.
>>
>> Even after your changes, there is still a significant difference between
>> the main repository and submodules: we have access to the object
>> database for the main repository, but not for submodules.
>>
>> So, for example, the following don't work for submodules:
>>
>> * `parse_object()` is used to ensure that references are only pointed at
>> valid objects, and that branches are only pointed at commit objects.
>>
>> * `peel_object()` is used to write the peeled version of references in
>> `packed-refs`, and to peel references while they are being iterated
>> over. Since this doesn't work, I think you can't write `packed-refs` in
>> a submodule.
>>
>> These limitations, I think, imply that submodule references have to be
>> treated as read-only.
> 
> Behind the scene submodule does add_submodule_odb(), which basically
> makes the submodule's odb an alternate of in-core odb. So odb access
> works. I was puzzled how submodules could by pass odb access at the
> beginning only to find that out. technical/api-ref-iteration.txt also
> mentions that you need to add_submodule_odb(), so I think it's
> deliberate (albeit hacky) design.

That's interesting. I didn't know it before.

But I still don't think that means that reference writing can work
correctly. If I try to set a submodule branch to an SHA-1 and I verify
that the SHA-1 points to a valid commit, how do I know that the commit
is in the same submodule that holds the reference?

> [...]

Michael

Re: [PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Duy Nguyen]

On Mon, Feb 20, 2017 at 7:30 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/20/2017 01:21 PM, Duy Nguyen wrote:
>> On Mon, Feb 20, 2017 at 7:11 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>>> On 02/18/2017 02:33 PM, Nguyễn Thái Ngọc Duy wrote:
>>>> Since submodule or not is irrelevant to files-backend after the last
>>>> patch, remove the parameter from files_downcast() and kill
>>>> files_assert_main_repository().
>>>>
>>>> PS. This implies that all ref operations are allowed for submodules. But
>>>> we may need to look more closely to see if that's really true...
>>>
>>> I think you are jumping the gun here.
>>>
>>> Even after your changes, there is still a significant difference between
>>> the main repository and submodules: we have access to the object
>>> database for the main repository, but not for submodules.
>>>
>>> So, for example, the following don't work for submodules:
>>>
>>> * `parse_object()` is used to ensure that references are only pointed at
>>> valid objects, and that branches are only pointed at commit objects.
>>>
>>> * `peel_object()` is used to write the peeled version of references in
>>> `packed-refs`, and to peel references while they are being iterated
>>> over. Since this doesn't work, I think you can't write `packed-refs` in
>>> a submodule.
>>>
>>> These limitations, I think, imply that submodule references have to be
>>> treated as read-only.
>>
>> Behind the scene submodule does add_submodule_odb(), which basically
>> makes the submodule's odb an alternate of in-core odb. So odb access
>> works. I was puzzled how submodules could by pass odb access at the
>> beginning only to find that out. technical/api-ref-iteration.txt also
>> mentions that you need to add_submodule_odb(), so I think it's
>> deliberate (albeit hacky) design.
>
> That's interesting. I didn't know it before.
>
> But I still don't think that means that reference writing can work
> correctly. If I try to set a submodule branch to an SHA-1 and I verify
> that the SHA-1 points to a valid commit, how do I know that the commit
> is in the same submodule that holds the reference?

Good point. So will the new flag be "read_only" (no reference to
submodule), or "submodule"? This flag will be passed in at ref-store
init time and kept in files_ref_store.
-- 
Duy

Re: [PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Michael Haggerty]

On 02/20/2017 01:33 PM, Duy Nguyen wrote:
> On Mon, Feb 20, 2017 at 7:30 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>> On 02/20/2017 01:21 PM, Duy Nguyen wrote:
>>> On Mon, Feb 20, 2017 at 7:11 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>>>> [...]
>>>> These limitations, I think, imply that submodule references have to be
>>>> treated as read-only.
>>>
>>> Behind the scene submodule does add_submodule_odb(), which basically
>>> makes the submodule's odb an alternate of in-core odb. So odb access
>>> works. I was puzzled how submodules could by pass odb access at the
>>> beginning only to find that out. technical/api-ref-iteration.txt also
>>> mentions that you need to add_submodule_odb(), so I think it's
>>> deliberate (albeit hacky) design.
>>
>> That's interesting. I didn't know it before.
>>
>> But I still don't think that means that reference writing can work
>> correctly. If I try to set a submodule branch to an SHA-1 and I verify
>> that the SHA-1 points to a valid commit, how do I know that the commit
>> is in the same submodule that holds the reference?
> 
> Good point. So will the new flag be "read_only" (no reference to
> submodule), or "submodule"? This flag will be passed in at ref-store
> init time and kept in files_ref_store.

I haven't checked carefully whether there are other operations that
don't work and/or don't make sense for submodules. If not, then
`read_only` would also be a fine name for the flag.

Michael

Re: [PATCH v4 14/15] files-backend: remove submodule_allowed from files_downcast()

[Duy Nguyen]

On Mon, Feb 20, 2017 at 7:11 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/18/2017 02:33 PM, Nguyễn Thái Ngọc Duy wrote:
>> Since submodule or not is irrelevant to files-backend after the last
>> patch, remove the parameter from files_downcast() and kill
>> files_assert_main_repository().
>>
>> PS. This implies that all ref operations are allowed for submodules. But
>> we may need to look more closely to see if that's really true...
>
> I think you are jumping the gun here.
>
> Even after your changes, there is still a significant difference between
> the main repository and submodules: we have access to the object
> database for the main repository, but not for submodules.

I did jump the gun for another reason: files-backend makes function
calls to the frontend, which unconditionally target the main ref store
(e.g. resolve_ref_unsafe, delete_ref...). Of course, because
store-aware api does not exist. My decision (off-list) to add
test-ref-store was the right call. I would not have seen these because
I was not (and still am not) familiar with files-backend.c enough to
see its dark corners.

files-backend.c is not all unicorn and rainbow :(
-- 
Duy

[PATCH v4 15/15] refs: rename get_ref_store() to get_submodule_ref_store() and make it public

[Nguyễn Thái Ngọc Duy]

This function is intended to replace *_submodule() refs API. It provides
a ref store for a specific submodule, which can be operated on by a new
set of refs API.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 12 ++++++++----
 refs.h               | 11 +++++++++++
 refs/files-backend.c |  2 +-
 refs/refs-internal.h | 12 ------------
 4 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/refs.c b/refs.c
index 8035c3ea7..bc2247b59 100644
--- a/refs.c
+++ b/refs.c
@@ -1165,7 +1165,7 @@ int head_ref(each_ref_fn fn, void *cb_data)
 static int do_for_each_ref(const char *submodule, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(submodule);
+	struct ref_store *refs = get_submodule_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
@@ -1338,10 +1338,10 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
 		/* We need to strip off one or more trailing slashes */
 		char *stripped = xmemdupz(submodule, len);
 
-		refs = get_ref_store(stripped);
+		refs = get_submodule_ref_store(stripped);
 		free(stripped);
 	} else {
-		refs = get_ref_store(submodule);
+		refs = get_submodule_ref_store(submodule);
 	}
 
 	if (!refs)
@@ -1457,13 +1457,17 @@ struct ref_store *get_main_ref_store(void)
 	return refs;
 }
 
-struct ref_store *get_ref_store(const char *submodule)
+struct ref_store *get_submodule_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 	int ret;
 
 	if (!submodule || !*submodule) {
+		/*
+		 * FIXME: This case is ideally not allowed. But that
+		 * can't happen until we clean up all the callers.
+		 */
 		return get_main_ref_store();
 	}
 
diff --git a/refs.h b/refs.h
index a35b687d7..5bd065f12 100644
--- a/refs.h
+++ b/refs.h
@@ -556,5 +556,16 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int ref_storage_backend_exists(const char *name);
 
 struct ref_store *get_main_ref_store(void);
+/*
+ * Return the ref_store instance for the specified submodule. For the
+ * main repository, use submodule==NULL; such a call cannot fail. For
+ * a submodule, the submodule must exist and be a nonbare repository,
+ * otherwise return NULL. If the requested reference store has not yet
+ * been initialized, initialize it first.
+ *
+ * For backwards compatibility, submodule=="" is treated the same as
+ * submodule==NULL.
+ */
+struct ref_store *get_submodule_ref_store(const char *submodule);
 
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index b8ccf4e47..603601f1b 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3125,7 +3125,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), "set_head_symref");
+		files_downcast(get_main_ref_store(), "set_head_symref");
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 3ef020acf..ed6527ce1 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -640,18 +640,6 @@ struct ref_store {
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-/*
- * Return the ref_store instance for the specified submodule. For the
- * main repository, use submodule==NULL; such a call cannot fail. For
- * a submodule, the submodule must exist and be a nonbare repository,
- * otherwise return NULL. If the requested reference store has not yet
- * been initialized, initialize it first.
- *
- * For backwards compatibility, submodule=="" is treated the same as
- * submodule==NULL.
- */
-struct ref_store *get_ref_store(const char *submodule);
-
 const char *resolve_ref_recursively(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
-- 
2.11.0.157.gd943d85

Re: [PATCH v4 00/15] Remove submodule from files-backend.c

[Michael Haggerty]

On 02/18/2017 02:32 PM, Nguyễn Thái Ngọc Duy wrote:
> v4:

I very much like the direction of this patch series. I reviewed the
design pretty carefully and left some comments about it, and skimmed
through the code changes. But I haven't yet reviewed the code in detail.
I'll wait for your reaction to my design comments before doing so.

Thanks,
Michael

Re: [PATCH v4 00/15] Remove submodule from files-backend.c

[Duy Nguyen]

On Mon, Feb 20, 2017 at 7:42 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/18/2017 02:32 PM, Nguyễn Thái Ngọc Duy wrote:
>> v4:
>
> I very much like the direction of this patch series. I reviewed the
> design pretty carefully and left some comments about it, and skimmed
> through the code changes. But I haven't yet reviewed the code in detail.
> I'll wait for your reaction to my design comments before doing so.

Unless there are some mails in transit, thanks for the review. The
comments I haven't replied to usually mean "I agree" (but not writing
unless I could add anything after).
-- 
Duy

[PATCH v5 00/24] Remove submodule from files-backend.c

[Nguyễn Thái Ngọc Duy]

v5 goes a bit longer than v4, basically:

 - files_path() is broken down into three smaller functions,
   files_{packed_refs,reflog,refname}_path().

 - most of store-based api is added because..

 - test-ref-store.c is added with t1405 and t1406 for some basic tests
   I'm not aimimg for complete ref store coverage. But we can continue
   to improve from there.

 - refs_store_init() now takes a "permission" flag, like open().
   Operations are allowed or forbidden based on this flag. The
   submodule_allowed flag is killed. files_assert_main.. remains.

 - get_*_ref_store() remain public api because it's used by
   test-ref-store.c and pack-refs.c.

 - files-backend.c should now make no function calls that implicitly
   target the main store. But this will have to be tested more to be
   sure. I'm tempted to add a tracing backend just for this purpose.

Junio, if you take this on 'pu', you'll have to kick my other two
series out (they should not even compile). I'm not resending them
until I get a "looks mostly ok" from Michael. No point in updating
them when this series keeps moving.

This series is also available on my github repo. branch
files-backend-git-dir-2.

Nguyễn Thái Ngọc Duy (24):
  refs.h: add forward declaration for structs used in this file
  files-backend: make files_log_ref_write() static
  files-backend: add and use files_packed_refs_path()
  files-backend: convert git_path() to strbuf_git_path()
  files-backend: move "logs/" out of TMP_RENAMED_LOG
  files-backend: add and use files_reflog_path()
  files-backend: add and use files_refname_path()
  files-backend: remove the use of git_path()
  refs.c: introduce get_main_ref_store()
  refs: rename lookup_ref_store() to lookup_submodule_ref_store()
  refs.c: flatten get_ref_store() a bit
  refs.c: kill register_ref_store(), add register_submodule_ref_store()
  refs.c: make get_main_ref_store() public and use it
  path.c: move some code out of strbuf_git_path_submodule()
  refs: move submodule code out of files-backend.c
  files-backend: replace submodule_allowed check in files_downcast()
  refs: rename get_ref_store() to get_submodule_ref_store() and make it public
  refs: add new ref-store api
  refs: new transaction related ref-store api
  files-backend: avoid ref api targetting main ref store
  refs: delete pack_refs() in favor of refs_pack_refs()
  t/helper: add test-ref-store to test ref-store functions
  t1405: some basic tests on main ref store
  t1406: new tests for submodule ref store

 Makefile                                |   1 +
 builtin/pack-refs.c                     |   2 +-
 path.c                                  |  34 +--
 refs.c                                  | 411 ++++++++++++++++++--------
 refs.h                                  | 100 ++++++-
 refs/files-backend.c                    | 509 +++++++++++++++++++++-----------
 refs/refs-internal.h                    |  64 +---
 submodule.c                             |  31 ++
 submodule.h                             |   1 +
 t/helper/.gitignore                     |   1 +
 t/helper/test-ref-store.c (new)         | 274 +++++++++++++++++
 t/t1405-main-ref-store.sh (new +x)      | 123 ++++++++
 t/t1406-submodule-ref-store.sh (new +x) |  95 ++++++
 13 files changed, 1269 insertions(+), 377 deletions(-)
 create mode 100644 t/helper/test-ref-store.c
 create mode 100755 t/t1405-main-ref-store.sh
 create mode 100755 t/t1406-submodule-ref-store.sh

-- 
2.11.0.157.gd943d85

[PATCH v5 01/24] refs.h: add forward declaration for structs used in this file

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/refs.h b/refs.h
index 9fbff90e7..c494b641a 100644
--- a/refs.h
+++ b/refs.h
@@ -1,6 +1,11 @@
 #ifndef REFS_H
 #define REFS_H
 
+struct object_id;
+struct ref_transaction;
+struct strbuf;
+struct string_list;
+
 /*
  * Resolve a reference, recursively following symbolic refererences.
  *
@@ -144,7 +149,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
  * `ref_transaction_commit` is called.  So `ref_transaction_verify`
  * won't report a verification failure until the commit is attempted.
  */
-struct ref_transaction;
 
 /*
  * Bit values set in the flags argument passed to each_ref_fn() and
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 01/24] refs.h: add forward declaration for structs used in this file

[Stefan Beller]

On Wed, Feb 22, 2017 at 6:04 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/refs.h b/refs.h
> index 9fbff90e7..c494b641a 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -1,6 +1,11 @@
>  #ifndef REFS_H
>  #define REFS_H
>
> +struct object_id;
> +struct ref_transaction;
> +struct strbuf;
> +struct string_list;
> +
>  /*
>   * Resolve a reference, recursively following symbolic refererences.
>   *
> @@ -144,7 +149,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
>   * `ref_transaction_commit` is called.  So `ref_transaction_verify`
>   * won't report a verification failure until the commit is attempted.
>   */
> -struct ref_transaction;

Leaving the detailed comment about ref_transaction dangling?
I can understand if you don't want to move it with the declaration,
as you want all declarations terse in a few lines.
Maybe move the comment to be part of the first large comment
(The one that you can see in the first hunk, starting with
" * Resolve a reference, recursively following")

Maybe Michael has a better idea how to make this comment
more accessible to the casual refs-reader.

Thanks,
Stefan

Re: [PATCH v5 01/24] refs.h: add forward declaration for structs used in this file

[Duy Nguyen]

On Thu, Feb 23, 2017 at 1:18 AM, Stefan Beller <sbeller@google.com> wrote:
> On Wed, Feb 22, 2017 at 6:04 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>>  refs.h | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/refs.h b/refs.h
>> index 9fbff90e7..c494b641a 100644
>> --- a/refs.h
>> +++ b/refs.h
>> @@ -1,6 +1,11 @@
>>  #ifndef REFS_H
>>  #define REFS_H
>>
>> +struct object_id;
>> +struct ref_transaction;
>> +struct strbuf;
>> +struct string_list;
>> +
>>  /*
>>   * Resolve a reference, recursively following symbolic refererences.
>>   *
>> @@ -144,7 +149,6 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
>>   * `ref_transaction_commit` is called.  So `ref_transaction_verify`
>>   * won't report a verification failure until the commit is attempted.
>>   */
>> -struct ref_transaction;
>
> Leaving the detailed comment about ref_transaction dangling?
> I can understand if you don't want to move it with the declaration,
> as you want all declarations terse in a few lines.
> Maybe move the comment to be part of the first large comment
> (The one that you can see in the first hunk, starting with
> " * Resolve a reference, recursively following")

I thought the comment block covered the following declarations too,
not just ref_transaction. But on second read it's not that.
Transaction functions are way down below. I'll probably move
ref_transaction back where it was.
-- 
Duy

[PATCH v5 02/24] files-backend: make files_log_ref_write() static

[Nguyễn Thái Ngọc Duy]

Created in 5f3c3a4e6f (files_log_ref_write: new function - 2015-11-10)
but probably never used outside refs-internal.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 3 +++
 refs/refs-internal.h | 4 ----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index db3bd42a9..1ebd59ec0 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,6 +165,9 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+			       const unsigned char *new_sha1, const char *msg,
+			       int flags, struct strbuf *err);
 
 static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 {
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index fa93c9a32..f732473e1 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -228,10 +228,6 @@ struct ref_transaction {
 	enum ref_transaction_state state;
 };
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err);
-
 /*
  * Check for entries in extras that are within the specified
  * directory, where dirname is a reference directory name including
-- 
2.11.0.157.gd943d85

[PATCH v5 03/24] files-backend: add and use files_packed_refs_path()

[Nguyễn Thái Ngọc Duy]

Keep repo-related path handling in one place. This will make it easier
to add submodule/multiworktree support later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 1ebd59ec0..4676525de 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -923,6 +923,8 @@ struct files_ref_store {
 	 */
 	const char *submodule;
 
+	char *packed_refs_path;
+
 	struct ref_entry *loose;
 	struct packed_ref_cache *packed;
 };
@@ -985,7 +987,14 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
-	refs->submodule = xstrdup_or_null(submodule);
+	if (submodule) {
+		refs->submodule = xstrdup(submodule);
+		refs->packed_refs_path = git_pathdup_submodule(
+			refs->submodule, "packed-refs");
+		return ref_store;
+	}
+
+	refs->packed_refs_path = git_pathdup("packed-refs");
 
 	return ref_store;
 }
@@ -1153,19 +1162,18 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 	strbuf_release(&line);
 }
 
+static const char *files_packed_refs_path(struct files_ref_store *refs)
+{
+	return refs->packed_refs_path;
+}
+
 /*
  * Get the packed_ref_cache for the specified files_ref_store,
  * creating it if necessary.
  */
 static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
 {
-	char *packed_refs_file;
-
-	if (refs->submodule)
-		packed_refs_file = git_pathdup_submodule(refs->submodule,
-							 "packed-refs");
-	else
-		packed_refs_file = git_pathdup("packed-refs");
+	const char *packed_refs_file = files_packed_refs_path(refs);
 
 	if (refs->packed &&
 	    !stat_validity_check(&refs->packed->validity, packed_refs_file))
@@ -1184,7 +1192,6 @@ static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *ref
 			fclose(f);
 		}
 	}
-	free(packed_refs_file);
 	return refs->packed;
 }
 
@@ -2160,7 +2167,7 @@ static int lock_packed_refs(struct files_ref_store *refs, int flags)
 	}
 
 	if (hold_lock_file_for_update_timeout(
-			    &packlock, git_path("packed-refs"),
+			    &packlock, files_packed_refs_path(refs),
 			    flags, timeout_value) < 0)
 		return -1;
 	/*
@@ -2426,7 +2433,7 @@ static int repack_without_refs(struct files_ref_store *refs,
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(refs, 0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		unable_to_lock_message(files_packed_refs_path(refs), errno, err);
 		return -1;
 	}
 	packed = get_packed_refs(refs);
-- 
2.11.0.157.gd943d85

[PATCH v5 04/24] files-backend: convert git_path() to strbuf_git_path()

[Nguyễn Thái Ngọc Duy]

git_path() and friends are going to be killed in files-backend.c in near
future. And because there's a risk with overwriting buffer in
git_path(), let's convert them all to strbuf_git_path(). We'll have
easier time killing/converting strbuf_git_path() then because we won't
have to worry about memory management again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 139 +++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 106 insertions(+), 33 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 4676525de..435db1293 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2319,6 +2319,7 @@ enum {
 static void try_remove_empty_parents(const char *refname, unsigned int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 	char *p, *q;
 	int i;
 
@@ -2340,14 +2341,19 @@ static void try_remove_empty_parents(const char *refname, unsigned int flags)
 		if (q == p)
 			break;
 		strbuf_setlen(&buf, q - buf.buf);
-		if ((flags & REMOVE_EMPTY_PARENTS_REF) &&
-		    rmdir(git_path("%s", buf.buf)))
+
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "%s", buf.buf);
+		if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REF;
-		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) &&
-		    rmdir(git_path("logs/%s", buf.buf)))
+
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "logs/%s", buf.buf);
+		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
 	}
 	strbuf_release(&buf);
+	strbuf_release(&sb);
 }
 
 /* make sure nobody touched the ref, and unlink */
@@ -2509,11 +2515,16 @@ static int files_delete_refs(struct ref_store *ref_store,
  */
 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
 
-static int rename_tmp_log_callback(const char *path, void *cb)
+struct rename_cb {
+	const char *tmp_renamed_log;
+	int true_errno;
+};
+
+static int rename_tmp_log_callback(const char *path, void *cb_data)
 {
-	int *true_errno = cb;
+	struct rename_cb *cb = cb_data;
 
-	if (rename(git_path(TMP_RENAMED_LOG), path)) {
+	if (rename(cb->tmp_renamed_log, path)) {
 		/*
 		 * rename(a, b) when b is an existing directory ought
 		 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
@@ -2521,7 +2532,7 @@ static int rename_tmp_log_callback(const char *path, void *cb)
 		 * but report EISDIR to raceproof_create_file() so
 		 * that it knows to retry.
 		 */
-		*true_errno = errno;
+		cb->true_errno = errno;
 		if (errno == ENOTDIR)
 			errno = EISDIR;
 		return -1;
@@ -2532,20 +2543,26 @@ static int rename_tmp_log_callback(const char *path, void *cb)
 
 static int rename_tmp_log(const char *newrefname)
 {
-	char *path = git_pathdup("logs/%s", newrefname);
-	int ret, true_errno;
+	struct strbuf path = STRBUF_INIT;
+	struct strbuf tmp = STRBUF_INIT;
+	struct rename_cb cb;
+	int ret;
 
-	ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
+	strbuf_git_path(&path, "logs/%s", newrefname);
+	strbuf_git_path(&tmp, TMP_RENAMED_LOG);
+	cb.tmp_renamed_log = tmp.buf;
+	ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
 	if (ret) {
 		if (errno == EISDIR)
-			error("directory not empty: %s", path);
+			error("directory not empty: %s", path.buf);
 		else
 			error("unable to move logfile %s to %s: %s",
-			      git_path(TMP_RENAMED_LOG), path,
-			      strerror(true_errno));
+			      tmp.buf, path.buf,
+			      strerror(cb.true_errno));
 	}
 
-	free(path);
+	strbuf_release(&path);
+	strbuf_release(&tmp);
 	return ret;
 }
 
@@ -2586,9 +2603,15 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
-	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+	struct strbuf sb_oldref = STRBUF_INIT;
+	struct strbuf sb_newref = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
+	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	log = !lstat(sb_oldref.buf, &loginfo);
+	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2602,7 +2625,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
+	if (ret)
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
@@ -2681,13 +2709,19 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
+	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
+	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
+	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
+	strbuf_release(&sb_newref);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
 
 	return 1;
 }
@@ -2861,18 +2895,24 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
 				  git_committer_info(0), msg);
 	if (result) {
+		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
+		strbuf_git_path(&sb, "logs/%s", refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
-			    git_path("logs/%s", refname), strerror(save_errno));
+			    sb.buf, strerror(save_errno));
+		strbuf_release(&sb);
 		close(logfd);
 		return -1;
 	}
 	if (close(logfd)) {
+		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
+		strbuf_git_path(&sb, "logs/%s", refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
-			    git_path("logs/%s", refname), strerror(save_errno));
+			    sb.buf, strerror(save_errno));
+		strbuf_release(&sb);
 		return -1;
 	}
 	return 0;
@@ -3092,22 +3132,32 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
+	int ret;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_exists");
 
-	return !lstat(git_path("logs/%s", refname), &st) &&
-		S_ISREG(st.st_mode);
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "delete_reflog");
 
-	return remove_path(git_path("logs/%s", refname));
+	strbuf_git_path(&sb, "logs/%s", refname);
+	ret = remove_path(sb.buf);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
@@ -3162,7 +3212,9 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3268,7 +3320,9 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "for_each_reflog_ent");
 
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	strbuf_git_path(&sb, "logs/%s", refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3350,12 +3404,15 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 {
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
+	struct strbuf sb = STRBUF_INIT;
 
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "reflog_iterator_begin");
 
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	iter->dir_iterator = dir_iterator_begin(git_path("logs"));
+	strbuf_git_path(&sb, "logs");
+	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	strbuf_release(&sb);
 	return ref_iterator;
 }
 
@@ -3693,6 +3750,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	char *head_ref = NULL;
 	int head_type;
 	struct object_id head_oid;
+	struct strbuf sb = STRBUF_INIT;
 
 	assert(err);
 
@@ -3814,7 +3872,9 @@ static int files_transaction_commit(struct ref_store *ref_store,
 			if (!(update->type & REF_ISPACKED) ||
 			    update->type & REF_ISSYMREF) {
 				/* It is a loose reference. */
-				if (unlink_or_msg(git_path("%s", lock->ref_name), err)) {
+				strbuf_reset(&sb);
+				strbuf_git_path(&sb, "%s", lock->ref_name);
+				if (unlink_or_msg(sb.buf, err)) {
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto cleanup;
 				}
@@ -3834,7 +3894,9 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 	/* Delete the reflogs of any references that were deleted: */
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
-		if (!unlink_or_warn(git_path("logs/%s", ref_to_delete->string)))
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		if (!unlink_or_warn(sb.buf))
 			try_remove_empty_parents(ref_to_delete->string,
 						 REMOVE_EMPTY_PARENTS_REFLOG);
 	}
@@ -3842,6 +3904,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	clear_loose_ref_cache(refs);
 
 cleanup:
+	strbuf_release(&sb);
 	transaction->state = REF_TRANSACTION_CLOSED;
 
 	for (i = 0; i < transaction->nr; i++) {
@@ -4108,18 +4171,28 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct strbuf sb = STRBUF_INIT;
+
 	/* Check validity (but we don't need the result): */
 	files_downcast(ref_store, 0, "init_db");
 
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
+	strbuf_git_path(&sb, "refs/heads");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
+	strbuf_git_path(&sb, "refs/tags");
+	safe_create_dir(sb.buf, 1);
+	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
+		strbuf_git_path(&sb, "refs/heads");
+		adjust_shared_perm(sb.buf);
+		strbuf_reset(&sb);
+		strbuf_git_path(&sb, "refs/tags");
+		adjust_shared_perm(sb.buf);
 	}
+	strbuf_release(&sb);
 	return 0;
 }
 
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 04/24] files-backend: convert git_path() to strbuf_git_path()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> git_path() and friends are going to be killed in files-backend.c in near
> future. And because there's a risk with overwriting buffer in
> git_path(), let's convert them all to strbuf_git_path(). We'll have
> easier time killing/converting strbuf_git_path() then because we won't
> have to worry about memory management again.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 139 +++++++++++++++++++++++++++++++++++++++------------
>  1 file changed, 106 insertions(+), 33 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 4676525de..435db1293 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> [...]
> @@ -2586,9 +2603,15 @@ static int files_rename_ref(struct ref_store *ref_store,
>  	int flag = 0, logmoved = 0;
>  	struct ref_lock *lock;
>  	struct stat loginfo;
> -	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
> +	struct strbuf sb_oldref = STRBUF_INIT;
> +	struct strbuf sb_newref = STRBUF_INIT;
> +	struct strbuf tmp_renamed_log = STRBUF_INIT;
> +	int log, ret;
>  	struct strbuf err = STRBUF_INIT;
>  
> +	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> +	log = !lstat(sb_oldref.buf, &loginfo);
> +	strbuf_release(&sb_oldref);
>  	if (log && S_ISLNK(loginfo.st_mode))
>  		return error("reflog for %s is a symlink", oldrefname);
>  
> @@ -2602,7 +2625,12 @@ static int files_rename_ref(struct ref_store *ref_store,
>  	if (!rename_ref_available(oldrefname, newrefname))
>  		return 1;
>  
> -	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
> +	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> +	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
> +	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
> +	strbuf_release(&sb_oldref);
> +	strbuf_release(&tmp_renamed_log);
> +	if (ret)
>  		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
>  			oldrefname, strerror(errno));
>  
> @@ -2681,13 +2709,19 @@ static int files_rename_ref(struct ref_store *ref_store,
>  	log_all_ref_updates = flag;
>  
>   rollbacklog:
> -	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
> +	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
> +	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> +	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
>  		error("unable to restore logfile %s from %s: %s",
>  			oldrefname, newrefname, strerror(errno));
> +	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
>  	if (!logmoved && log &&
> -	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
> +	    rename(tmp_renamed_log.buf, sb_oldref.buf))
>  		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
>  			oldrefname, strerror(errno));

It feels like you're writing, releasing, re-writing these strbufs more
than necessary. Maybe it would be clearer to set them once, and on
errors set `ret = error()` then jump to a label here...

> +	strbuf_release(&sb_newref);
> +	strbuf_release(&sb_oldref);
> +	strbuf_release(&tmp_renamed_log);
>  

...and change this to `return ret`?

>  	return 1;
>  }
> [...]
> @@ -4108,18 +4171,28 @@ static int files_reflog_expire(struct ref_store *ref_store,
>  
>  static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
>  {
> +	struct strbuf sb = STRBUF_INIT;
> +
>  	/* Check validity (but we don't need the result): */
>  	files_downcast(ref_store, 0, "init_db");
>  
>  	/*
>  	 * Create .git/refs/{heads,tags}
>  	 */
> -	safe_create_dir(git_path("refs/heads"), 1);
> -	safe_create_dir(git_path("refs/tags"), 1);
> +	strbuf_git_path(&sb, "refs/heads");
> +	safe_create_dir(sb.buf, 1);
> +	strbuf_reset(&sb);
> +	strbuf_git_path(&sb, "refs/tags");
> +	safe_create_dir(sb.buf, 1);
> +	strbuf_reset(&sb);
>  	if (get_shared_repository()) {
> -		adjust_shared_perm(git_path("refs/heads"));
> -		adjust_shared_perm(git_path("refs/tags"));
> +		strbuf_git_path(&sb, "refs/heads");
> +		adjust_shared_perm(sb.buf);
> +		strbuf_reset(&sb);
> +		strbuf_git_path(&sb, "refs/tags");
> +		adjust_shared_perm(sb.buf);
>  	}
> +	strbuf_release(&sb);
>  	return 0;
>  }

It looks to me like `safe_create_dir()` already has the ability to
`adjust_shared_perm()`, or am I missing something? (I realize that this
is preexisting code.)

Michael

Re: [PATCH v5 04/24] files-backend: convert git_path() to strbuf_git_path()

[Duy Nguyen]

On Wed, Mar 1, 2017 at 12:06 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>> @@ -2681,13 +2709,19 @@ static int files_rename_ref(struct ref_store *ref_store,
>>       log_all_ref_updates = flag;
>>
>>   rollbacklog:
>> -     if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
>> +     strbuf_git_path(&sb_newref, "logs/%s", newrefname);
>> +     strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
>> +     if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
>>               error("unable to restore logfile %s from %s: %s",
>>                       oldrefname, newrefname, strerror(errno));
>> +     strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
>>       if (!logmoved && log &&
>> -         rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
>> +         rename(tmp_renamed_log.buf, sb_oldref.buf))
>>               error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
>>                       oldrefname, strerror(errno));
>
> It feels like you're writing, releasing, re-writing these strbufs more
> than necessary. Maybe it would be clearer to set them once, and on
> errors set `ret = error()` then jump to a label here...
>
>> +     strbuf_release(&sb_newref);
>> +     strbuf_release(&sb_oldref);
>> +     strbuf_release(&tmp_renamed_log);
>>
>
> ...and change this to `return ret`?

If that's ok with you, will do. I kept the patch dumb so the reader
does not have to keep track of many things when they check if there
are any behavior changes.

>>  static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
>>  {
>> +     struct strbuf sb = STRBUF_INIT;
>> +
>>       /* Check validity (but we don't need the result): */
>>       files_downcast(ref_store, 0, "init_db");
>>
>>       /*
>>        * Create .git/refs/{heads,tags}
>>        */
>> -     safe_create_dir(git_path("refs/heads"), 1);
>> -     safe_create_dir(git_path("refs/tags"), 1);
>> +     strbuf_git_path(&sb, "refs/heads");
>> +     safe_create_dir(sb.buf, 1);
>> +     strbuf_reset(&sb);
>> +     strbuf_git_path(&sb, "refs/tags");
>> +     safe_create_dir(sb.buf, 1);
>> +     strbuf_reset(&sb);
>>       if (get_shared_repository()) {
>> -             adjust_shared_perm(git_path("refs/heads"));
>> -             adjust_shared_perm(git_path("refs/tags"));
>> +             strbuf_git_path(&sb, "refs/heads");
>> +             adjust_shared_perm(sb.buf);
>> +             strbuf_reset(&sb);
>> +             strbuf_git_path(&sb, "refs/tags");
>> +             adjust_shared_perm(sb.buf);
>>       }
>> +     strbuf_release(&sb);
>>       return 0;
>>  }
>
> It looks to me like `safe_create_dir()` already has the ability to
> `adjust_shared_perm()`, or am I missing something? (I realize that this
> is preexisting code.)

Yeah you're right. I guess this code was written when
safe_create_dir() didn't do that. That certainly shortens this patch.
-- 
Duy

[PATCH v5 05/24] files-backend: move "logs/" out of TMP_RENAMED_LOG

[Nguyễn Thái Ngọc Duy]

This makes reflog path building consistent, always in the form of

    strbuf_git_path(sb, "logs/%s", refname);

It reduces the mental workload a bit in the next patch when that
function call is converted.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 435db1293..69946b0de 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2513,7 +2513,7 @@ static int files_delete_refs(struct ref_store *ref_store,
  * IOW, to avoid cross device rename errors, the temporary renamed log must
  * live into logs/refs.
  */
-#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
+#define TMP_RENAMED_LOG  "refs/.tmp-renamed-log"
 
 struct rename_cb {
 	const char *tmp_renamed_log;
@@ -2549,7 +2549,7 @@ static int rename_tmp_log(const char *newrefname)
 	int ret;
 
 	strbuf_git_path(&path, "logs/%s", newrefname);
-	strbuf_git_path(&tmp, TMP_RENAMED_LOG);
+	strbuf_git_path(&tmp, "logs/%s", TMP_RENAMED_LOG);
 	cb.tmp_renamed_log = tmp.buf;
 	ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
 	if (ret) {
@@ -2626,12 +2626,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 		return 1;
 
 	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	strbuf_git_path(&tmp_renamed_log, "logs/%s", TMP_RENAMED_LOG);
 	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
 	strbuf_release(&sb_oldref);
 	strbuf_release(&tmp_renamed_log);
 	if (ret)
-		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
+		return error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
 	if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
@@ -2714,10 +2714,10 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
-	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
+	strbuf_git_path(&tmp_renamed_log, "logs/%s", TMP_RENAMED_LOG);
 	if (!logmoved && log &&
 	    rename(tmp_renamed_log.buf, sb_oldref.buf))
-		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
+		error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 	strbuf_release(&sb_newref);
 	strbuf_release(&sb_oldref);
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 05/24] files-backend: move "logs/" out of TMP_RENAMED_LOG

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> This makes reflog path building consistent, always in the form of
> 
>     strbuf_git_path(sb, "logs/%s", refname);
> 
> It reduces the mental workload a bit in the next patch when that
> function call is converted.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 435db1293..69946b0de 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -2513,7 +2513,7 @@ static int files_delete_refs(struct ref_store *ref_store,
>   * IOW, to avoid cross device rename errors, the temporary renamed log must
>   * live into logs/refs.
>   */
> -#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
> +#define TMP_RENAMED_LOG  "refs/.tmp-renamed-log"

The constant name feels a little bit misleading now that it is not the
name of a logfile but rather a reference name. OTOH "tmp-renamed-log" is
*in* the reference name so I guess it's not really wrong.

>  struct rename_cb {
>  	const char *tmp_renamed_log;
> @@ -2549,7 +2549,7 @@ static int rename_tmp_log(const char *newrefname)
>  	int ret;
>  
>  	strbuf_git_path(&path, "logs/%s", newrefname);
> -	strbuf_git_path(&tmp, TMP_RENAMED_LOG);
> +	strbuf_git_path(&tmp, "logs/%s", TMP_RENAMED_LOG);
>  	cb.tmp_renamed_log = tmp.buf;
>  	ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
>  	if (ret) {
> @@ -2626,12 +2626,12 @@ static int files_rename_ref(struct ref_store *ref_store,
>  		return 1;
>  
>  	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
> -	strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
> +	strbuf_git_path(&tmp_renamed_log, "logs/%s", TMP_RENAMED_LOG);
>  	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
>  	strbuf_release(&sb_oldref);
>  	strbuf_release(&tmp_renamed_log);
>  	if (ret)
> -		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
> +		return error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
>  			oldrefname, strerror(errno));

It seems like it would be preferable to use `sb_oldref.buf` and
`tmp.buf` when building the error message. But I guess that `tmp.buf`
might include some path preceding "logs/" that is unwanted in the error
message? But it's a shame to hardcode the file naming scheme here again.

Maybe we *do* want the path in the error message?

It just occurred to me: this temporary logfile lives in the main
repository, right? What if a worktree reference is being renamed? Part
of the advertised use of worktrees is that the worktree might live far
from the main directory, or even on removable media. But it's not
possible to rename files across partitions. Maybe this will come out in
the wash once worktrees are ref_stores themselves.

For that matter, what if a user tries to rename a worktree ref into a
common ref or vice versa?

>  	if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
> [...]

Michael

Re: [PATCH v5 05/24] files-backend: move "logs/" out of TMP_RENAMED_LOG

[Duy Nguyen]

On Wed, Mar 1, 2017 at 12:19 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>> @@ -2513,7 +2513,7 @@ static int files_delete_refs(struct ref_store *ref_store,
>>   * IOW, to avoid cross device rename errors, the temporary renamed log must
>>   * live into logs/refs.
>>   */
>> -#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
>> +#define TMP_RENAMED_LOG  "refs/.tmp-renamed-log"
>
> The constant name feels a little bit misleading now that it is not the
> name of a logfile but rather a reference name. OTOH "tmp-renamed-log" is
> *in* the reference name so I guess it's not really wrong.

Heh.. I had a similar internal debate and almost renamed it to
tmp_renamed_refname. But then it's technically not a valid ref name
either (starting with a leading dot). My lazy side came in and
declared that doing nothing was always the right way.

>>  struct rename_cb {
>>       const char *tmp_renamed_log;
>> @@ -2549,7 +2549,7 @@ static int rename_tmp_log(const char *newrefname)
>>       int ret;
>>
>>       strbuf_git_path(&path, "logs/%s", newrefname);
>> -     strbuf_git_path(&tmp, TMP_RENAMED_LOG);
>> +     strbuf_git_path(&tmp, "logs/%s", TMP_RENAMED_LOG);
>>       cb.tmp_renamed_log = tmp.buf;
>>       ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
>>       if (ret) {
>> @@ -2626,12 +2626,12 @@ static int files_rename_ref(struct ref_store *ref_store,
>>               return 1;
>>
>>       strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
>> -     strbuf_git_path(&tmp_renamed_log, TMP_RENAMED_LOG);
>> +     strbuf_git_path(&tmp_renamed_log, "logs/%s", TMP_RENAMED_LOG);
>>       ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
>>       strbuf_release(&sb_oldref);
>>       strbuf_release(&tmp_renamed_log);
>>       if (ret)
>> -             return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
>> +             return error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
>>                       oldrefname, strerror(errno));
>
> It seems like it would be preferable to use `sb_oldref.buf` and
> `tmp.buf` when building the error message. But I guess that `tmp.buf`
> might include some path preceding "logs/" that is unwanted in the error
> message? But it's a shame to hardcode the file naming scheme here again.
>
> Maybe we *do* want the path in the error message?

It's an error, every piece of details matters. So yeah I'm inclined we
should print full path.

> It just occurred to me: this temporary logfile lives in the main
> repository, right? What if a worktree reference is being renamed? Part
> of the advertised use of worktrees is that the worktree might live far
> from the main directory, or even on removable media. But it's not
> possible to rename files across partitions. Maybe this will come out in
> the wash once worktrees are ref_stores themselves.

The actual working directory may be separated, but all the things that
belong to .git (even of a linked worktree) stay in the main worktree's
.git directory. And I don't think we ever support having a .git
directory on multiple partitions. You can rename refs freely even when
the worktree is on a detached removable drive.

> For that matter, what if a user tries to rename a worktree ref into a
> common ref or vice versa?

Interesting. It should work, it's just a
rename(".git/worktrees/blah/refs/bisect/good",
".git/refs/heads/saved") after the path translation done by
git_path().
-- 
Duy

[PATCH v5 06/24] files-backend: add and use files_reflog_path()

[Nguyễn Thái Ngọc Duy]

Keep repo-related path handling in one place. This will make it easier
to add submodule/multiworktree support later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 148 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 89 insertions(+), 59 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 69946b0de..7b4ea4c56 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -165,7 +165,8 @@ static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
 					  const char *dirname, size_t len,
 					  int incomplete);
 static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
-static int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+static int files_log_ref_write(struct files_ref_store *refs,
+			       const char *refname, const unsigned char *old_sha1,
 			       const unsigned char *new_sha1, const char *msg,
 			       int flags, struct strbuf *err);
 
@@ -1167,6 +1168,18 @@ static const char *files_packed_refs_path(struct files_ref_store *refs)
 	return refs->packed_refs_path;
 }
 
+static void files_reflog_path(struct files_ref_store *refs,
+			      struct strbuf *sb,
+			      const char *refname)
+{
+	if (!refname) {
+		strbuf_git_path(sb, "logs");
+		return;
+	}
+
+	strbuf_git_path(sb, "logs/%s", refname);
+}
+
 /*
  * Get the packed_ref_cache for the specified files_ref_store,
  * creating it if necessary.
@@ -2316,7 +2329,9 @@ enum {
  * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
  * REMOVE_EMPTY_PARENTS_REFLOG.
  */
-static void try_remove_empty_parents(const char *refname, unsigned int flags)
+static void try_remove_empty_parents(struct files_ref_store *refs,
+				     const char *refname,
+				     unsigned int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
@@ -2348,7 +2363,7 @@ static void try_remove_empty_parents(const char *refname, unsigned int flags)
 			flags &= ~REMOVE_EMPTY_PARENTS_REF;
 
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "logs/%s", buf.buf);
+		files_reflog_path(refs, &sb, buf.buf);
 		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
 	}
@@ -2541,15 +2556,15 @@ static int rename_tmp_log_callback(const char *path, void *cb_data)
 	}
 }
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 {
 	struct strbuf path = STRBUF_INIT;
 	struct strbuf tmp = STRBUF_INIT;
 	struct rename_cb cb;
 	int ret;
 
-	strbuf_git_path(&path, "logs/%s", newrefname);
-	strbuf_git_path(&tmp, "logs/%s", TMP_RENAMED_LOG);
+	files_reflog_path(refs, &path, newrefname);
+	files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
 	cb.tmp_renamed_log = tmp.buf;
 	ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
 	if (ret) {
@@ -2609,7 +2624,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_reflog_path(refs, &sb_oldref, oldrefname);
 	log = !lstat(sb_oldref.buf, &loginfo);
 	strbuf_release(&sb_oldref);
 	if (log && S_ISLNK(loginfo.st_mode))
@@ -2625,8 +2640,8 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (!rename_ref_available(oldrefname, newrefname))
 		return 1;
 
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
-	strbuf_git_path(&tmp_renamed_log, "logs/%s", TMP_RENAMED_LOG);
+	files_reflog_path(refs, &sb_oldref, oldrefname);
+	files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	ret = log && rename(sb_oldref.buf, tmp_renamed_log.buf);
 	strbuf_release(&sb_oldref);
 	strbuf_release(&tmp_renamed_log);
@@ -2667,7 +2682,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 		}
 	}
 
-	if (log && rename_tmp_log(newrefname))
+	if (log && rename_tmp_log(refs, newrefname))
 		goto rollback;
 
 	logmoved = log;
@@ -2709,12 +2724,12 @@ static int files_rename_ref(struct ref_store *ref_store,
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	strbuf_git_path(&sb_newref, "logs/%s", newrefname);
-	strbuf_git_path(&sb_oldref, "logs/%s", oldrefname);
+	files_reflog_path(refs, &sb_newref, newrefname);
+	files_reflog_path(refs, &sb_oldref, oldrefname);
 	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
-	strbuf_git_path(&tmp_renamed_log, "logs/%s", TMP_RENAMED_LOG);
+	files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 	if (!logmoved && log &&
 	    rename(tmp_renamed_log.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
@@ -2782,10 +2797,15 @@ static int open_or_create_logfile(const char *path, void *cb)
  * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
  * return -1.
  */
-static int log_ref_setup(const char *refname, int force_create,
+static int log_ref_setup(struct files_ref_store *refs,
+			 const char *refname, int force_create,
 			 int *logfd, struct strbuf *err)
 {
-	char *logfile = git_pathdup("logs/%s", refname);
+	struct strbuf logfile_sb = STRBUF_INIT;
+	char *logfile;
+
+	files_reflog_path(refs, &logfile_sb, refname);
+	logfile = strbuf_detach(&logfile_sb, NULL);
 
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
@@ -2835,12 +2855,11 @@ static int files_create_reflog(struct ref_store *ref_store,
 			       const char *refname, int force_create,
 			       struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "create_reflog");
 	int fd;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "create_reflog");
-
-	if (log_ref_setup(refname, force_create, &fd, err))
+	if (log_ref_setup(refs, refname, force_create, &fd, err))
 		return -1;
 
 	if (fd >= 0)
@@ -2875,7 +2894,8 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
 	return 0;
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
+int files_log_ref_write(struct files_ref_store *refs,
+			const char *refname, const unsigned char *old_sha1,
 			const unsigned char *new_sha1, const char *msg,
 			int flags, struct strbuf *err)
 {
@@ -2884,7 +2904,8 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 	if (log_all_ref_updates == LOG_REFS_UNSET)
 		log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
 
-	result = log_ref_setup(refname, flags & REF_FORCE_CREATE_REFLOG,
+	result = log_ref_setup(refs, refname,
+			       flags & REF_FORCE_CREATE_REFLOG,
 			       &logfd, err);
 
 	if (result)
@@ -2898,7 +2919,7 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
-		strbuf_git_path(&sb, "logs/%s", refname);
+		files_reflog_path(refs, &sb, refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
 			    sb.buf, strerror(save_errno));
 		strbuf_release(&sb);
@@ -2909,7 +2930,7 @@ int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
 		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
-		strbuf_git_path(&sb, "logs/%s", refname);
+		files_reflog_path(refs, &sb, refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
 			    sb.buf, strerror(save_errno));
 		strbuf_release(&sb);
@@ -2970,7 +2991,8 @@ static int commit_ref_update(struct files_ref_store *refs,
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (files_log_ref_write(lock->ref_name, lock->old_oid.hash, sha1,
+	if (files_log_ref_write(refs, lock->ref_name,
+				lock->old_oid.hash, sha1,
 				logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
@@ -3002,8 +3024,9 @@ static int commit_ref_update(struct files_ref_store *refs,
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (files_log_ref_write("HEAD", lock->old_oid.hash, sha1,
-					  logmsg, 0, &log_err)) {
+			if (files_log_ref_write(refs, "HEAD",
+						lock->old_oid.hash, sha1,
+						logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
 			}
@@ -3035,24 +3058,26 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 	return ret;
 }
 
-static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+static void update_symref_reflog(struct files_ref_store *refs,
+				 struct ref_lock *lock, const char *refname,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
 	if (logmsg && !read_ref(target, new_sha1) &&
-	    files_log_ref_write(refname, lock->old_oid.hash, new_sha1,
-				logmsg, 0, &err)) {
+	    files_log_ref_write(refs, refname, lock->old_oid.hash,
+				new_sha1, logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
 }
 
-static int create_symref_locked(struct ref_lock *lock, const char *refname,
+static int create_symref_locked(struct files_ref_store *refs,
+				struct ref_lock *lock, const char *refname,
 				const char *target, const char *logmsg)
 {
 	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(lock, refname, target, logmsg);
+		update_symref_reflog(refs, lock, refname, target, logmsg);
 		return 0;
 	}
 
@@ -3060,7 +3085,7 @@ static int create_symref_locked(struct ref_lock *lock, const char *refname,
 		return error("unable to fdopen %s: %s",
 			     lock->lk->tempfile.filename.buf, strerror(errno));
 
-	update_symref_reflog(lock, refname, target, logmsg);
+	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
 	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
@@ -3089,13 +3114,20 @@ static int files_create_symref(struct ref_store *ref_store,
 		return -1;
 	}
 
-	ret = create_symref_locked(lock, refname, target, logmsg);
+	ret = create_symref_locked(refs, lock, refname, target, logmsg);
 	unlock_ref(lock);
 	return ret;
 }
 
 int set_worktree_head_symref(const char *gitdir, const char *target)
 {
+	/*
+	 * FIXME: this obviously will not work well for future refs
+	 * backends. This function needs to die.
+	 */
+	struct files_ref_store *refs =
+		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
+
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3122,7 +3154,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	lock->lk = &head_lock;
 	lock->ref_name = xstrdup(head_rel);
 
-	ret = create_symref_locked(lock, head_rel, target, NULL);
+	ret = create_symref_locked(refs, lock, head_rel, target, NULL);
 
 	unlock_ref(lock); /* will free lock */
 	strbuf_release(&head_path);
@@ -3132,14 +3164,13 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_exists");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_reflog_path(refs, &sb, refname);
 	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
 	strbuf_release(&sb);
 	return ret;
@@ -3148,13 +3179,12 @@ static int files_reflog_exists(struct ref_store *ref_store,
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "delete_reflog");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_reflog_path(refs, &sb, refname);
 	ret = remove_path(sb.buf);
 	strbuf_release(&sb);
 	return ret;
@@ -3204,15 +3234,14 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     each_reflog_ent_fn fn,
 					     void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
 	int ret = 0, at_tail = 1;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_reflog_path(refs, &sb, refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3313,14 +3342,13 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     const char *refname,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent");
-
-	strbuf_git_path(&sb, "logs/%s", refname);
+	files_reflog_path(refs, &sb, refname);
 	logfp = fopen(sb.buf, "r");
 	strbuf_release(&sb);
 	if (!logfp)
@@ -3402,15 +3430,14 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_iterator_begin");
-
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	strbuf_git_path(&sb, "logs");
+	files_reflog_path(refs, &sb, NULL);
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
 	strbuf_release(&sb);
 	return ref_iterator;
@@ -3835,7 +3862,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (files_log_ref_write(lock->ref_name,
+			if (files_log_ref_write(refs,
+						lock->ref_name,
 						lock->old_oid.hash,
 						update->new_sha1,
 						update->msg, update->flags,
@@ -3895,9 +3923,9 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	/* Delete the reflogs of any references that were deleted: */
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "logs/%s", ref_to_delete->string);
+		files_reflog_path(refs, &sb, ref_to_delete->string);
 		if (!unlink_or_warn(sb.buf))
-			try_remove_empty_parents(ref_to_delete->string,
+			try_remove_empty_parents(refs, ref_to_delete->string,
 						 REMOVE_EMPTY_PARENTS_REFLOG);
 	}
 
@@ -3921,7 +3949,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 			 * can only work because we have already
 			 * removed the lockfile.)
 			 */
-			try_remove_empty_parents(update->refname,
+			try_remove_empty_parents(refs, update->refname,
 						 REMOVE_EMPTY_PARENTS_REF);
 		}
 	}
@@ -4072,6 +4100,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
+	struct strbuf log_file_sb = STRBUF_INIT;
 	char *log_file;
 	int status = 0;
 	int type;
@@ -4100,7 +4129,8 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		return 0;
 	}
 
-	log_file = git_pathdup("logs/%s", refname);
+	files_reflog_path(refs, &log_file_sb, refname);
+	log_file = strbuf_detach(&log_file_sb, NULL);
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 		/*
 		 * Even though holding $GIT_DIR/logs/$reflog.lock has
-- 
2.11.0.157.gd943d85

[PATCH v5 07/24] files-backend: add and use files_refname_path()

[Nguyễn Thái Ngọc Duy]

Keep repo-related path handling in one place. This will make it easier
to add submodule/multiworktree support later.

This automatically adds the "if submodule then use the submodule version
of git_path" to other call sites too. But it does not mean those
operations are sumodule-ready. Not yet.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 45 +++++++++++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 20 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 7b4ea4c56..72f4e1746 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1180,6 +1180,18 @@ static void files_reflog_path(struct files_ref_store *refs,
 	strbuf_git_path(sb, "logs/%s", refname);
 }
 
+static void files_refname_path(struct files_ref_store *refs,
+			       struct strbuf *sb,
+			       const char *refname)
+{
+	if (refs->submodule) {
+		strbuf_git_path_submodule(sb, refs->submodule, "%s", refname);
+		return;
+	}
+
+	strbuf_git_path(sb, "%s", refname);
+}
+
 /*
  * Get the packed_ref_cache for the specified files_ref_store,
  * creating it if necessary.
@@ -1251,10 +1263,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 	size_t path_baselen;
 	int err = 0;
 
-	if (refs->submodule)
-		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
-	else
-		strbuf_git_path(&path, "%s", dirname);
+	files_refname_path(refs, &path, dirname);
 	path_baselen = path.len;
 
 	if (err) {
@@ -1396,10 +1405,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	*type = 0;
 	strbuf_reset(&sb_path);
 
-	if (refs->submodule)
-		strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
-	else
-		strbuf_git_path(&sb_path, "%s", refname);
+	files_refname_path(refs, &sb_path, refname);
 
 	path = sb_path.buf;
 
@@ -1587,7 +1593,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
 	*lock_p = lock = xcalloc(1, sizeof(*lock));
 
 	lock->ref_name = xstrdup(refname);
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_refname_path(refs, &ref_file, refname);
 
 retry:
 	switch (safe_create_leading_directories(ref_file.buf)) {
@@ -2059,7 +2065,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 	if (flags & REF_DELETING)
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_refname_path(refs, &ref_file, refname);
 	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
 					lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
@@ -2358,7 +2364,7 @@ static void try_remove_empty_parents(struct files_ref_store *refs,
 		strbuf_setlen(&buf, q - buf.buf);
 
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "%s", buf.buf);
+		files_refname_path(refs, &sb, buf.buf);
 		if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REF;
 
@@ -2668,7 +2674,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			struct strbuf path = STRBUF_INIT;
 			int result;
 
-			strbuf_git_path(&path, "%s", newrefname);
+			files_refname_path(refs, &path, newrefname);
 			result = remove_empty_directories(&path);
 			strbuf_release(&path);
 
@@ -3901,7 +3907,7 @@ static int files_transaction_commit(struct ref_store *ref_store,
 			    update->type & REF_ISSYMREF) {
 				/* It is a loose reference. */
 				strbuf_reset(&sb);
-				strbuf_git_path(&sb, "%s", lock->ref_name);
+				files_refname_path(refs, &sb, lock->ref_name);
 				if (unlink_or_msg(sb.buf, err)) {
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto cleanup;
@@ -4201,25 +4207,24 @@ static int files_reflog_expire(struct ref_store *ref_store,
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, 0, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "init_db");
-
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	strbuf_git_path(&sb, "refs/heads");
+	files_refname_path(refs, &sb, "refs/heads");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
-	strbuf_git_path(&sb, "refs/tags");
+	files_refname_path(refs, &sb, "refs/tags");
 	safe_create_dir(sb.buf, 1);
 	strbuf_reset(&sb);
 	if (get_shared_repository()) {
-		strbuf_git_path(&sb, "refs/heads");
+		files_refname_path(refs, &sb, "refs/heads");
 		adjust_shared_perm(sb.buf);
 		strbuf_reset(&sb);
-		strbuf_git_path(&sb, "refs/tags");
+		files_refname_path(refs, &sb, "refs/tags");
 		adjust_shared_perm(sb.buf);
 	}
 	strbuf_release(&sb);
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 07/24] files-backend: add and use files_refname_path()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> Keep repo-related path handling in one place. This will make it easier
> to add submodule/multiworktree support later.
> 
> This automatically adds the "if submodule then use the submodule version
> of git_path" to other call sites too. But it does not mean those
> operations are sumodule-ready. Not yet.

s/sumodule/submodule/

> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 45 +++++++++++++++++++++++++--------------------
>  1 file changed, 25 insertions(+), 20 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 7b4ea4c56..72f4e1746 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -1180,6 +1180,18 @@ static void files_reflog_path(struct files_ref_store *refs,
>  	strbuf_git_path(sb, "logs/%s", refname);
>  }
>  
> +static void files_refname_path(struct files_ref_store *refs,
> +			       struct strbuf *sb,
> +			       const char *refname)
> +{
> +	if (refs->submodule) {
> +		strbuf_git_path_submodule(sb, refs->submodule, "%s", refname);
> +		return;
> +	}
> +
> +	strbuf_git_path(sb, "%s", refname);
> +}

Maybe it's just me, but I find it odd to exit early here when the first
exit isn't due to an error. For me, structuring this like `if ()
call1(); else call2();` would make it clearer that the two code paths
are equally-valid alternatives, and either one or the other will be
executed.

I had the same feeling when I read `files_reflog_path()`

>  /*
>   * Get the packed_ref_cache for the specified files_ref_store,
>   * creating it if necessary.
> @@ -1251,10 +1263,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
>  	size_t path_baselen;
>  	int err = 0;
>  
> -	if (refs->submodule)
> -		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
> -	else
> -		strbuf_git_path(&path, "%s", dirname);
> +	files_refname_path(refs, &path, dirname);

It's so nice to see these ugly `if (refs->submodule)` code blocks
disappearing!

> [...]

Michael

Re: [PATCH v5 07/24] files-backend: add and use files_refname_path()

[Duy Nguyen]

On Wed, Mar 1, 2017 at 12:41 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
>> Keep repo-related path handling in one place. This will make it easier
>> to add submodule/multiworktree support later.
>>
>> This automatically adds the "if submodule then use the submodule version
>> of git_path" to other call sites too. But it does not mean those
>> operations are sumodule-ready. Not yet.
>
> s/sumodule/submodule/
>
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>>  refs/files-backend.c | 45 +++++++++++++++++++++++++--------------------
>>  1 file changed, 25 insertions(+), 20 deletions(-)
>>
>> diff --git a/refs/files-backend.c b/refs/files-backend.c
>> index 7b4ea4c56..72f4e1746 100644
>> --- a/refs/files-backend.c
>> +++ b/refs/files-backend.c
>> @@ -1180,6 +1180,18 @@ static void files_reflog_path(struct files_ref_store *refs,
>>       strbuf_git_path(sb, "logs/%s", refname);
>>  }
>>
>> +static void files_refname_path(struct files_ref_store *refs,
>> +                            struct strbuf *sb,
>> +                            const char *refname)
>> +{
>> +     if (refs->submodule) {
>> +             strbuf_git_path_submodule(sb, refs->submodule, "%s", refname);
>> +             return;
>> +     }
>> +
>> +     strbuf_git_path(sb, "%s", refname);
>> +}
>
> Maybe it's just me, but I find it odd to exit early here when the first
> exit isn't due to an error. For me, structuring this like `if ()
> call1(); else call2();` would make it clearer that the two code paths
> are equally-valid alternatives, and either one or the other will be
> executed.

Its original version probably looked better. This is another case of
future patches influencing back the past ones: I structure the patch
so that in future we mostly add lines, or delete whole (in this case,
I believe), not modify a lot of lines. I think the readability does
not degrade too much though, so it's probably ok.
-- 
Duy

Re: [PATCH v5 07/24] files-backend: add and use files_refname_path()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> Keep repo-related path handling in one place. This will make it easier
> to add submodule/multiworktree support later.
> 
> This automatically adds the "if submodule then use the submodule version
> of git_path" to other call sites too. But it does not mean those
> operations are sumodule-ready. Not yet.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 45 +++++++++++++++++++++++++--------------------
>  1 file changed, 25 insertions(+), 20 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 7b4ea4c56..72f4e1746 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> [...]
> @@ -1251,10 +1263,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
>  	size_t path_baselen;
>  	int err = 0;
>  
> -	if (refs->submodule)
> -		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
> -	else
> -		strbuf_git_path(&path, "%s", dirname);
> +	files_refname_path(refs, &path, dirname);
>  	path_baselen = path.len;
>  
>  	if (err) {

I just noticed another thing. After this change, `err` is never set, so
the `if (err)` block (and `err` itself) can be deleted.

> [...]

Michael

[PATCH v5 08/24] files-backend: remove the use of git_path()

[Nguyễn Thái Ngọc Duy]

Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
deciding what goes where (*). The end goal is to pass $GIT_DIR only. A
refs "view" of a linked worktree is a logical ref store that combines
two files backends together.

(*) Not entirely true since strbuf_git_path_submodule() still does path
translation underneath. But that's for another patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 43 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 38 insertions(+), 5 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 72f4e1746..a390eaadf 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -923,7 +923,8 @@ struct files_ref_store {
 	 * store:
 	 */
 	const char *submodule;
-
+	char *gitdir;
+	char *gitcommondir;
 	char *packed_refs_path;
 
 	struct ref_entry *loose;
@@ -985,6 +986,8 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
+	struct strbuf sb = STRBUF_INIT;
+	const char *gitdir = get_git_dir();
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
@@ -995,7 +998,11 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 		return ref_store;
 	}
 
-	refs->packed_refs_path = git_pathdup("packed-refs");
+	refs->gitdir = xstrdup(gitdir);
+	get_common_dir_noenv(&sb, gitdir);
+	refs->gitcommondir = strbuf_detach(&sb, NULL);
+	strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
+	refs->packed_refs_path = strbuf_detach(&sb, NULL);
 
 	return ref_store;
 }
@@ -1173,11 +1180,26 @@ static void files_reflog_path(struct files_ref_store *refs,
 			      const char *refname)
 {
 	if (!refname) {
-		strbuf_git_path(sb, "logs");
+		/*
+		 * FIXME: of course this is wrong in multi worktree
+		 * setting. To be fixed real soon.
+		 */
+		strbuf_addf(sb, "%s/logs", refs->gitcommondir);
 		return;
 	}
 
-	strbuf_git_path(sb, "logs/%s", refname);
+	switch (ref_type(refname)) {
+	case REF_TYPE_PER_WORKTREE:
+	case REF_TYPE_PSEUDOREF:
+		strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
+		break;
+	case REF_TYPE_NORMAL:
+		strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
+		break;
+	default:
+		die("BUG: unknown ref type %d of ref %s",
+		    ref_type(refname), refname);
+	}
 }
 
 static void files_refname_path(struct files_ref_store *refs,
@@ -1189,7 +1211,18 @@ static void files_refname_path(struct files_ref_store *refs,
 		return;
 	}
 
-	strbuf_git_path(sb, "%s", refname);
+	switch (ref_type(refname)) {
+	case REF_TYPE_PER_WORKTREE:
+	case REF_TYPE_PSEUDOREF:
+		strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
+		break;
+	case REF_TYPE_NORMAL:
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
+		break;
+	default:
+		die("BUG: unknown ref type %d of ref %s",
+		    ref_type(refname), refname);
+	}
 }
 
 /*
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 08/24] files-backend: remove the use of git_path()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> Given $GIT_DIR and $GIT_COMMON_DIR, files-backend is now in charge of
> deciding what goes where (*). The end goal is to pass $GIT_DIR only. A
> refs "view" of a linked worktree is a logical ref store that combines
> two files backends together.
> 
> (*) Not entirely true since strbuf_git_path_submodule() still does path
> translation underneath. But that's for another patch.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs/files-backend.c | 43 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 38 insertions(+), 5 deletions(-)
> 
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index 72f4e1746..a390eaadf 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -923,7 +923,8 @@ struct files_ref_store {
>  	 * store:
>  	 */
>  	const char *submodule;
> -
> +	char *gitdir;
> +	char *gitcommondir;
>  	char *packed_refs_path;
>  
>  	struct ref_entry *loose;
> @@ -985,6 +986,8 @@ static struct ref_store *files_ref_store_create(const char *submodule)
>  {
>  	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
>  	struct ref_store *ref_store = (struct ref_store *)refs;
> +	struct strbuf sb = STRBUF_INIT;
> +	const char *gitdir = get_git_dir();
>  
>  	base_ref_store_init(ref_store, &refs_be_files);
>  
> @@ -995,7 +998,11 @@ static struct ref_store *files_ref_store_create(const char *submodule)
>  		return ref_store;
>  	}
>  
> -	refs->packed_refs_path = git_pathdup("packed-refs");
> +	refs->gitdir = xstrdup(gitdir);
> +	get_common_dir_noenv(&sb, gitdir);
> +	refs->gitcommondir = strbuf_detach(&sb, NULL);
> +	strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
> +	refs->packed_refs_path = strbuf_detach(&sb, NULL);

`git_path()` and friends avoid adding an extra `/` if `git_dir()`
already ends in a slash or if it is the empty string. Here you don't
have that functionality. Is that intentional?

Same thing below, too.

>  
>  	return ref_store;
>  }
> @@ -1173,11 +1180,26 @@ static void files_reflog_path(struct files_ref_store *refs,
>  			      const char *refname)
>  {
>  	if (!refname) {
> -		strbuf_git_path(sb, "logs");
> +		/*
> +		 * FIXME: of course this is wrong in multi worktree
> +		 * setting. To be fixed real soon.
> +		 */
> +		strbuf_addf(sb, "%s/logs", refs->gitcommondir);
>  		return;
>  	}
>  
> -	strbuf_git_path(sb, "logs/%s", refname);
> +	switch (ref_type(refname)) {
> +	case REF_TYPE_PER_WORKTREE:
> +	case REF_TYPE_PSEUDOREF:
> +		strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
> +		break;
> +	case REF_TYPE_NORMAL:
> +		strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
> +		break;
> +	default:
> +		die("BUG: unknown ref type %d of ref %s",
> +		    ref_type(refname), refname);
> +	}
>  }
>  
>  static void files_refname_path(struct files_ref_store *refs,
> @@ -1189,7 +1211,18 @@ static void files_refname_path(struct files_ref_store *refs,
>  		return;
>  	}
>  
> -	strbuf_git_path(sb, "%s", refname);
> +	switch (ref_type(refname)) {
> +	case REF_TYPE_PER_WORKTREE:
> +	case REF_TYPE_PSEUDOREF:
> +		strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
> +		break;
> +	case REF_TYPE_NORMAL:
> +		strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
> +		break;
> +	default:
> +		die("BUG: unknown ref type %d of ref %s",
> +		    ref_type(refname), refname);
> +	}
>  }
>  
>  /*
> 

Michael

Re: [PATCH v5 08/24] files-backend: remove the use of git_path()

[Duy Nguyen]

On Wed, Mar 1, 2017 at 12:50 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>> @@ -995,7 +998,11 @@ static struct ref_store *files_ref_store_create(const char *submodule)
>>               return ref_store;
>>       }
>>
>> -     refs->packed_refs_path = git_pathdup("packed-refs");
>> +     refs->gitdir = xstrdup(gitdir);
>> +     get_common_dir_noenv(&sb, gitdir);
>> +     refs->gitcommondir = strbuf_detach(&sb, NULL);
>> +     strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
>> +     refs->packed_refs_path = strbuf_detach(&sb, NULL);
>
> `git_path()` and friends avoid adding an extra `/` if `git_dir()`
> already ends in a slash or if it is the empty string. Here you don't
> have that functionality. Is that intentional?

Kind of. I noticed that behavior but the thinking was, this $GIT_DIR
thing is going to get replaced soon anyway, and because the the uses
of these paths are very clear (in three groups) that avoiding
redundant slashes does not buy us anything extra, it's just more code.
-- 
Duy

[PATCH v5 09/24] refs.c: introduce get_main_ref_store()

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/refs.c b/refs.c
index 81b64b4ed..dab1a21ac 100644
--- a/refs.c
+++ b/refs.c
@@ -1456,15 +1456,23 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
+static struct ref_store *get_main_ref_store(void)
+{
+	struct ref_store *refs;
+
+	if (main_ref_store)
+		return main_ref_store;
+
+	refs = ref_store_init(NULL);
+	return refs;
+}
+
 struct ref_store *get_ref_store(const char *submodule)
 {
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
-		refs = lookup_ref_store(NULL);
-
-		if (!refs)
-			refs = ref_store_init(NULL);
+		return get_main_ref_store();
 	} else {
 		refs = lookup_ref_store(submodule);
 
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 09/24] refs.c: introduce get_main_ref_store()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index 81b64b4ed..dab1a21ac 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -1456,15 +1456,23 @@ static struct ref_store *ref_store_init(const char *submodule)
>  	return refs;
>  }
>  
> +static struct ref_store *get_main_ref_store(void)
> +{
> +	struct ref_store *refs;
> +
> +	if (main_ref_store)
> +		return main_ref_store;
> +
> +	refs = ref_store_init(NULL);
> +	return refs;

Unnecessary temporary variable?

> [...]

Michael

Re: [PATCH v5 09/24] refs.c: introduce get_main_ref_store()

[Duy Nguyen]

On Wed, Mar 1, 2017 at 12:51 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>>  refs.c | 16 ++++++++++++----
>>  1 file changed, 12 insertions(+), 4 deletions(-)
>>
>> diff --git a/refs.c b/refs.c
>> index 81b64b4ed..dab1a21ac 100644
>> --- a/refs.c
>> +++ b/refs.c
>> @@ -1456,15 +1456,23 @@ static struct ref_store *ref_store_init(const char *submodule)
>>       return refs;
>>  }
>>
>> +static struct ref_store *get_main_ref_store(void)
>> +{
>> +     struct ref_store *refs;
>> +
>> +     if (main_ref_store)
>> +             return main_ref_store;
>> +
>> +     refs = ref_store_init(NULL);
>> +     return refs;
>
> Unnecessary temporary variable?

That's the price for doing too much mechanical conversion :-P On
second read, I think I did that on purpose (or by luck) because the
"kill register_ref_store" patch needs this intermediate "refs" so we
can save it to main_ref_store. Cleaner future patch for the minor
uncleanliness in the current one.
-- 
Duy

[PATCH v5 10/24] refs: rename lookup_ref_store() to lookup_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

With get_main_ref_store() being used inside get_ref_store(),
lookup_ref_store() is only used for submodule code path. Rename to
reflect that and delete dead code.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index dab1a21ac..8b36d97c0 100644
--- a/refs.c
+++ b/refs.c
@@ -1395,17 +1395,13 @@ static struct ref_store *main_ref_store;
 static struct hashmap submodule_ref_stores;
 
 /*
- * Return the ref_store instance for the specified submodule (or the
- * main repository if submodule is NULL). If that ref_store hasn't
- * been initialized yet, return NULL.
+ * Return the ref_store instance for the specified submodule. If that
+ * ref_store hasn't been initialized yet, return NULL.
  */
-static struct ref_store *lookup_ref_store(const char *submodule)
+static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 {
 	struct submodule_hash_entry *entry;
 
-	if (!submodule)
-		return main_ref_store;
-
 	if (!submodule_ref_stores.tablesize)
 		/* It's initialized on demand in register_ref_store(). */
 		return NULL;
@@ -1474,7 +1470,7 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
 	} else {
-		refs = lookup_ref_store(submodule);
+		refs = lookup_submodule_ref_store(submodule);
 
 		if (!refs) {
 			struct strbuf submodule_sb = STRBUF_INIT;
@@ -1485,7 +1481,6 @@ struct ref_store *get_ref_store(const char *submodule)
 			strbuf_release(&submodule_sb);
 		}
 	}
-
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v5 11/24] refs.c: flatten get_ref_store() a bit

[Nguyễn Thái Ngọc Duy]

This helps the future changes in this code. And because get_ref_store()
is destined to become get_submodule_ref_store(), the "get main store"
code path will be removed eventually. After this the patch to delete
that code will be cleaner.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/refs.c b/refs.c
index 8b36d97c0..c284cb4f4 100644
--- a/refs.c
+++ b/refs.c
@@ -1465,22 +1465,21 @@ static struct ref_store *get_main_ref_store(void)
 
 struct ref_store *get_ref_store(const char *submodule)
 {
+	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
-	} else {
-		refs = lookup_submodule_ref_store(submodule);
+	}
 
-		if (!refs) {
-			struct strbuf submodule_sb = STRBUF_INIT;
+	refs = lookup_submodule_ref_store(submodule);
+	if (refs)
+		return refs;
 
-			strbuf_addstr(&submodule_sb, submodule);
-			if (is_nonbare_repository_dir(&submodule_sb))
-				refs = ref_store_init(submodule);
-			strbuf_release(&submodule_sb);
-		}
-	}
+	strbuf_addstr(&submodule_sb, submodule);
+	if (is_nonbare_repository_dir(&submodule_sb))
+		refs = ref_store_init(submodule);
+	strbuf_release(&submodule_sb);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

[PATCH v5 12/24] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Nguyễn Thái Ngọc Duy]

This is the last function in this code (besides public API) that takes
submodule argument and handles both main/submodule cases. Break it down,
move main store registration in get_main_ref_store() and keep the rest
in register_submodule_ref_store().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c | 50 ++++++++++++++++++++++++++------------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/refs.c b/refs.c
index c284cb4f4..6adc38e42 100644
--- a/refs.c
+++ b/refs.c
@@ -1412,29 +1412,6 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 }
 
 /*
- * Register the specified ref_store to be the one that should be used
- * for submodule (or the main repository if submodule is NULL). It is
- * a fatal error to call this function twice for the same submodule.
- */
-static void register_ref_store(struct ref_store *refs, const char *submodule)
-{
-	if (!submodule) {
-		if (main_ref_store)
-			die("BUG: main_ref_store initialized twice");
-
-		main_ref_store = refs;
-	} else {
-		if (!submodule_ref_stores.tablesize)
-			hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
-
-		if (hashmap_put(&submodule_ref_stores,
-				alloc_submodule_hash_entry(submodule, refs)))
-			die("BUG: ref_store for submodule '%s' initialized twice",
-			    submodule);
-	}
-}
-
-/*
  * Create, record, and return a ref_store instance for the specified
  * submodule (or the main repository if submodule is NULL).
  */
@@ -1448,7 +1425,6 @@ static struct ref_store *ref_store_init(const char *submodule)
 		die("BUG: reference backend %s is unknown", be_name);
 
 	refs = be->init(submodule);
-	register_ref_store(refs, submodule);
 	return refs;
 }
 
@@ -1460,9 +1436,32 @@ static struct ref_store *get_main_ref_store(void)
 		return main_ref_store;
 
 	refs = ref_store_init(NULL);
+	if (refs) {
+		if (main_ref_store)
+			die("BUG: main_ref_store initialized twice");
+
+		main_ref_store = refs;
+	}
 	return refs;
 }
 
+/*
+ * Register the specified ref_store to be the one that should be used
+ * for submodule. It is a fatal error to call this function twice for
+ * the same submodule.
+ */
+static void register_submodule_ref_store(struct ref_store *refs,
+					 const char *submodule)
+{
+	if (!submodule_ref_stores.tablesize)
+		hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
+
+	if (hashmap_put(&submodule_ref_stores,
+			alloc_submodule_hash_entry(submodule, refs)))
+		die("BUG: ref_store for submodule '%s' initialized twice",
+		    submodule);
+}
+
 struct ref_store *get_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
@@ -1480,6 +1479,9 @@ struct ref_store *get_ref_store(const char *submodule)
 	if (is_nonbare_repository_dir(&submodule_sb))
 		refs = ref_store_init(submodule);
 	strbuf_release(&submodule_sb);
+
+	if (refs)
+		register_submodule_ref_store(refs, submodule);
 	return refs;
 }
 
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 12/24] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> This is the last function in this code (besides public API) that takes
> submodule argument and handles both main/submodule cases. Break it down,
> move main store registration in get_main_ref_store() and keep the rest
> in register_submodule_ref_store().
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.c | 50 ++++++++++++++++++++++++++------------------------
>  1 file changed, 26 insertions(+), 24 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index c284cb4f4..6adc38e42 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -1412,29 +1412,6 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
>  }
>  
>  /*
> - * Register the specified ref_store to be the one that should be used
> - * for submodule (or the main repository if submodule is NULL). It is
> - * a fatal error to call this function twice for the same submodule.
> - */
> -static void register_ref_store(struct ref_store *refs, const char *submodule)
> -{
> -	if (!submodule) {
> -		if (main_ref_store)
> -			die("BUG: main_ref_store initialized twice");
> -
> -		main_ref_store = refs;
> -	} else {
> -		if (!submodule_ref_stores.tablesize)
> -			hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
> -
> -		if (hashmap_put(&submodule_ref_stores,
> -				alloc_submodule_hash_entry(submodule, refs)))
> -			die("BUG: ref_store for submodule '%s' initialized twice",
> -			    submodule);
> -	}
> -}
> -
> -/*
>   * Create, record, and return a ref_store instance for the specified
>   * submodule (or the main repository if submodule is NULL).
>   */
> @@ -1448,7 +1425,6 @@ static struct ref_store *ref_store_init(const char *submodule)
>  		die("BUG: reference backend %s is unknown", be_name);
>  
>  	refs = be->init(submodule);
> -	register_ref_store(refs, submodule);
>  	return refs;
>  }
>  
> @@ -1460,9 +1436,32 @@ static struct ref_store *get_main_ref_store(void)
>  		return main_ref_store;
>  
>  	refs = ref_store_init(NULL);
> +	if (refs) {
> +		if (main_ref_store)
> +			die("BUG: main_ref_store initialized twice");
> +
> +		main_ref_store = refs;
> +	}
>  	return refs;

Superfluous test: I don't think `ref_store_init()` ever returns NULL.
This also implies that you could check `main_ref_store` before calling
`ref_store_init()`, and eliminate a temporary.

>  }
>  
> +/*
> + * Register the specified ref_store to be the one that should be used
> + * for submodule. It is a fatal error to call this function twice for
> + * the same submodule.
> + */
> +static void register_submodule_ref_store(struct ref_store *refs,
> +					 const char *submodule)
> +{
> +	if (!submodule_ref_stores.tablesize)
> +		hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
> +
> +	if (hashmap_put(&submodule_ref_stores,
> +			alloc_submodule_hash_entry(submodule, refs)))
> +		die("BUG: ref_store for submodule '%s' initialized twice",
> +		    submodule);
> +}
> +
>  struct ref_store *get_ref_store(const char *submodule)
>  {
>  	struct strbuf submodule_sb = STRBUF_INIT;
> @@ -1480,6 +1479,9 @@ struct ref_store *get_ref_store(const char *submodule)
>  	if (is_nonbare_repository_dir(&submodule_sb))
>  		refs = ref_store_init(submodule);
>  	strbuf_release(&submodule_sb);
> +
> +	if (refs)

I think `refs` should always be non-NULL here for the same reason.

> +		register_submodule_ref_store(refs, submodule);
>  	return refs;
>  }

Michael

Re: [PATCH v5 12/24] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Duy Nguyen]

On Wed, Mar 1, 2017 at 1:03 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>>  struct ref_store *get_ref_store(const char *submodule)
>>  {
>>       struct strbuf submodule_sb = STRBUF_INIT;
>> @@ -1480,6 +1479,9 @@ struct ref_store *get_ref_store(const char *submodule)
>>       if (is_nonbare_repository_dir(&submodule_sb))
>>               refs = ref_store_init(submodule);
>>       strbuf_release(&submodule_sb);
>> +
>> +     if (refs)
>
> I think `refs` should always be non-NULL here for the same reason.

That's true if is_nonbar_repo... returns true. If it's false (e.g.
uninitialized submodule) then refs remains NULL from before (I didn't
know about this until I hit a segfault in rev-list in another series)
-- 
Duy

Re: [PATCH v5 12/24] refs.c: kill register_ref_store(), add register_submodule_ref_store()

[Michael Haggerty]

On 03/01/2017 01:00 PM, Duy Nguyen wrote:
> On Wed, Mar 1, 2017 at 1:03 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
>>>  struct ref_store *get_ref_store(const char *submodule)
>>>  {
>>>       struct strbuf submodule_sb = STRBUF_INIT;
>>> @@ -1480,6 +1479,9 @@ struct ref_store *get_ref_store(const char *submodule)
>>>       if (is_nonbare_repository_dir(&submodule_sb))
>>>               refs = ref_store_init(submodule);
>>>       strbuf_release(&submodule_sb);
>>> +
>>> +     if (refs)
>>
>> I think `refs` should always be non-NULL here for the same reason.
> 
> That's true if is_nonbar_repo... returns true. If it's false (e.g.
> uninitialized submodule) then refs remains NULL from before (I didn't
> know about this until I hit a segfault in rev-list in another series)

Oh, yes, true.

But given that, I think the code would be clearer if the two calls were
in the same if; i.e.,

 	refs = lookup_submodule_ref_store(submodule);
 	if (refs)
 		return refs;

 	strbuf_addstr(&submodule_sb, submodule);
 	if (is_nonbare_repository_dir(&submodule_sb)) {
 		refs = ref_store_init(submodule);
		register_submodule_ref_store(refs, submodule);
	}
 	strbuf_release(&submodule_sb);

 	return refs;

or even the `if (!is_nonbare_repository_dir(...)) goto cleanup;` pattern
to make it clearer that this is an error return.

Michael

[PATCH v5 13/24] refs.c: make get_main_ref_store() public and use it

[Nguyễn Thái Ngọc Duy]

get_ref_store() will soon be renamed to get_submodule_ref_store().
Together with future get_worktree_ref_store(), the three functions
provide an appropriate ref store for different operation modes. New APIs
will be added to operate directly on ref stores.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 36 ++++++++++++++++++------------------
 refs.h               |  3 +++
 refs/files-backend.c |  2 +-
 3 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/refs.c b/refs.c
index 6adc38e42..562834fc0 100644
--- a/refs.c
+++ b/refs.c
@@ -1314,7 +1314,7 @@ const char *resolve_ref_recursively(struct ref_store *refs,
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->init_db(refs, err);
 }
@@ -1322,7 +1322,7 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_ref_store(NULL), refname,
+	return resolve_ref_recursively(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1428,7 +1428,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	return refs;
 }
 
-static struct ref_store *get_main_ref_store(void)
+struct ref_store *get_main_ref_store(void)
 {
 	struct ref_store *refs;
 
@@ -1494,14 +1494,14 @@ void base_ref_store_init(struct ref_store *refs,
 /* backend functions */
 int pack_refs(unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->pack_refs(refs, flags);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->peel_ref(refs, refname, sha1);
 }
@@ -1509,7 +1509,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_symref(refs, ref_target, refs_heads_master,
 				       logmsg);
@@ -1518,7 +1518,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1528,14 +1528,14 @@ int verify_refname_available(const char *refname,
 			     const struct string_list *skip,
 			     struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
 }
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1546,7 +1546,7 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent_reverse(refs, refname,
 						     fn, cb_data);
@@ -1555,14 +1555,14 @@ int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_exists(refs, refname);
 }
@@ -1570,14 +1570,14 @@ int reflog_exists(const char *refname)
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_reflog(refs, refname);
 }
@@ -1589,7 +1589,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->reflog_expire(refs, refname, sha1, flags,
 				       prepare_fn, should_prune_fn,
@@ -1599,21 +1599,21 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
 int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->delete_refs(refs, refnames, flags);
 }
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index c494b641a..29013cb7e 100644
--- a/refs.h
+++ b/refs.h
@@ -2,6 +2,7 @@
 #define REFS_H
 
 struct object_id;
+struct ref_store;
 struct ref_transaction;
 struct strbuf;
 struct string_list;
@@ -559,4 +560,6 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 
 int ref_storage_backend_exists(const char *name);
 
+struct ref_store *get_main_ref_store(void);
+
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index a390eaadf..d80c27837 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3165,7 +3165,7 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_ref_store(NULL), 0, "set_head_symref");
+		files_downcast(get_main_ref_store(), 0, "set_head_symref");
 
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 13/24] refs.c: make get_main_ref_store() public and use it

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> get_ref_store() will soon be renamed to get_submodule_ref_store().
> Together with future get_worktree_ref_store(), the three functions
> provide an appropriate ref store for different operation modes. New APIs
> will be added to operate directly on ref stores.

Nice.

Michael

[PATCH v5 14/24] path.c: move some code out of strbuf_git_path_submodule()

[Nguyễn Thái Ngọc Duy]

refs is learning to avoid path rewriting that is done by
strbuf_git_path_submodule(). Factor out this code so it could be reused
by refs*

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 path.c      | 34 +++++++---------------------------
 submodule.c | 31 +++++++++++++++++++++++++++++++
 submodule.h |  1 +
 3 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/path.c b/path.c
index efcedafba..3451d2916 100644
--- a/path.c
+++ b/path.c
@@ -475,35 +475,16 @@ const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
 static int do_submodule_path(struct strbuf *buf, const char *path,
 			     const char *fmt, va_list args)
 {
-	const char *git_dir;
 	struct strbuf git_submodule_common_dir = STRBUF_INIT;
 	struct strbuf git_submodule_dir = STRBUF_INIT;
-	const struct submodule *sub;
-	int err = 0;
+	int ret;
 
-	strbuf_addstr(buf, path);
-	strbuf_complete(buf, '/');
-	strbuf_addstr(buf, ".git");
-
-	git_dir = read_gitfile(buf->buf);
-	if (git_dir) {
-		strbuf_reset(buf);
-		strbuf_addstr(buf, git_dir);
-	}
-	if (!is_git_directory(buf->buf)) {
-		gitmodules_config();
-		sub = submodule_from_path(null_sha1, path);
-		if (!sub) {
-			err = SUBMODULE_PATH_ERR_NOT_CONFIGURED;
-			goto cleanup;
-		}
-		strbuf_reset(buf);
-		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
-	}
-
-	strbuf_addch(buf, '/');
-	strbuf_addbuf(&git_submodule_dir, buf);
+	ret = submodule_to_gitdir(&git_submodule_dir, path);
+	if (ret)
+		goto cleanup;
 
+	strbuf_complete(&git_submodule_dir, '/');
+	strbuf_addbuf(buf, &git_submodule_dir);
 	strbuf_vaddf(buf, fmt, args);
 
 	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
@@ -514,8 +495,7 @@ static int do_submodule_path(struct strbuf *buf, const char *path,
 cleanup:
 	strbuf_release(&git_submodule_dir);
 	strbuf_release(&git_submodule_common_dir);
-
-	return err;
+	return ret;
 }
 
 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
diff --git a/submodule.c b/submodule.c
index 3b98766a6..36b8d1d11 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1514,3 +1514,34 @@ void absorb_git_dir_into_superproject(const char *prefix,
 		strbuf_release(&sb);
 	}
 }
+
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
+{
+	const struct submodule *sub;
+	const char *git_dir;
+	int ret = 0;
+
+	strbuf_reset(buf);
+	strbuf_addstr(buf, submodule);
+	strbuf_complete(buf, '/');
+	strbuf_addstr(buf, ".git");
+
+	git_dir = read_gitfile(buf->buf);
+	if (git_dir) {
+		strbuf_reset(buf);
+		strbuf_addstr(buf, git_dir);
+	}
+	if (!is_git_directory(buf->buf)) {
+		gitmodules_config();
+		sub = submodule_from_path(null_sha1, submodule);
+		if (!sub) {
+			ret = -1;
+			goto cleanup;
+		}
+		strbuf_reset(buf);
+		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
+	}
+
+cleanup:
+	return ret;
+}
diff --git a/submodule.h b/submodule.h
index 05ab674f0..fc3d0303e 100644
--- a/submodule.h
+++ b/submodule.h
@@ -81,6 +81,7 @@ extern int push_unpushed_submodules(struct sha1_array *commits,
 				    int dry_run);
 extern void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
 extern int parallel_submodules(void);
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 /*
  * Prepare the "env_array" parameter of a "struct child_process" for executing
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 14/24] path.c: move some code out of strbuf_git_path_submodule()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> refs is learning to avoid path rewriting that is done by
> strbuf_git_path_submodule(). Factor out this code so it could be reused
> by refs*
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  path.c      | 34 +++++++---------------------------
>  submodule.c | 31 +++++++++++++++++++++++++++++++
>  submodule.h |  1 +
>  3 files changed, 39 insertions(+), 27 deletions(-)
> 
> diff --git a/path.c b/path.c
> index efcedafba..3451d2916 100644
> --- a/path.c
> +++ b/path.c
> @@ -475,35 +475,16 @@ const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
>  static int do_submodule_path(struct strbuf *buf, const char *path,
>  			     const char *fmt, va_list args)
>  {
> -	const char *git_dir;
>  	struct strbuf git_submodule_common_dir = STRBUF_INIT;
>  	struct strbuf git_submodule_dir = STRBUF_INIT;
> -	const struct submodule *sub;
> -	int err = 0;
> +	int ret;
>  
> -	strbuf_addstr(buf, path);
> -	strbuf_complete(buf, '/');
> -	strbuf_addstr(buf, ".git");
> -
> -	git_dir = read_gitfile(buf->buf);
> -	if (git_dir) {
> -		strbuf_reset(buf);
> -		strbuf_addstr(buf, git_dir);
> -	}
> -	if (!is_git_directory(buf->buf)) {
> -		gitmodules_config();
> -		sub = submodule_from_path(null_sha1, path);
> -		if (!sub) {
> -			err = SUBMODULE_PATH_ERR_NOT_CONFIGURED;

I didn't read this patch too carefully, but where the old code used the
constant `SUBMODULE_PATH_ERR_NOT_CONFIGURED`, the new code returns -1.
In fact, now the constant is totally unused. It looks like there's some
more cleanup that could happen.

> -			goto cleanup;
> -		}
> -		strbuf_reset(buf);
> -		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
> -	}
> -
> -	strbuf_addch(buf, '/');
> -	strbuf_addbuf(&git_submodule_dir, buf);
> +	ret = submodule_to_gitdir(&git_submodule_dir, path);
> +	if (ret)
> +		goto cleanup;
>  
> +	strbuf_complete(&git_submodule_dir, '/');
> +	strbuf_addbuf(buf, &git_submodule_dir);
>  	strbuf_vaddf(buf, fmt, args);
>  
>  	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
> @@ -514,8 +495,7 @@ static int do_submodule_path(struct strbuf *buf, const char *path,
>  cleanup:
>  	strbuf_release(&git_submodule_dir);
>  	strbuf_release(&git_submodule_common_dir);
> -
> -	return err;
> +	return ret;
>  }
>  
>  char *git_pathdup_submodule(const char *path, const char *fmt, ...)
> diff --git a/submodule.c b/submodule.c
> index 3b98766a6..36b8d1d11 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -1514,3 +1514,34 @@ void absorb_git_dir_into_superproject(const char *prefix,
>  		strbuf_release(&sb);
>  	}
>  }
> +
> +int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
> +{
> +	const struct submodule *sub;
> +	const char *git_dir;
> +	int ret = 0;
> +
> +	strbuf_reset(buf);
> +	strbuf_addstr(buf, submodule);
> +	strbuf_complete(buf, '/');
> +	strbuf_addstr(buf, ".git");
> +
> +	git_dir = read_gitfile(buf->buf);
> +	if (git_dir) {
> +		strbuf_reset(buf);
> +		strbuf_addstr(buf, git_dir);
> +	}
> +	if (!is_git_directory(buf->buf)) {
> +		gitmodules_config();
> +		sub = submodule_from_path(null_sha1, submodule);
> +		if (!sub) {
> +			ret = -1;
> +			goto cleanup;
> +		}
> +		strbuf_reset(buf);
> +		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
> +	}
> +
> +cleanup:
> +	return ret;
> +}
> diff --git a/submodule.h b/submodule.h
> index 05ab674f0..fc3d0303e 100644
> --- a/submodule.h
> +++ b/submodule.h
> @@ -81,6 +81,7 @@ extern int push_unpushed_submodules(struct sha1_array *commits,
>  				    int dry_run);
>  extern void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
>  extern int parallel_submodules(void);
> +int submodule_to_gitdir(struct strbuf *buf, const char *submodule);

A docstring is always nice :-)

>  
>  /*
>   * Prepare the "env_array" parameter of a "struct child_process" for executing
> 

Michael

[PATCH v5 15/24] refs: move submodule code out of files-backend.c

[Nguyễn Thái Ngọc Duy]

files-backend is now initialized with a $GIT_DIR. Converting a submodule
path to where real submodule gitdir is located is done in get_ref_store().

This gives a slight performance improvement for submodules since we
don't convert submodule path to gitdir at every backend call like
before. We pay that once at ref-store creation.

More cleanup in files_downcast() and files_assert_main_repository()
follows shortly. It's separate to keep noises from this patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 20 ++++++++++++++------
 refs/files-backend.c | 24 ++----------------------
 refs/refs-internal.h |  9 ++++-----
 3 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/refs.c b/refs.c
index 562834fc0..67acae60c 100644
--- a/refs.c
+++ b/refs.c
@@ -9,6 +9,7 @@
 #include "refs/refs-internal.h"
 #include "object.h"
 #include "tag.h"
+#include "submodule.h"
 
 /*
  * List of all available backends
@@ -1413,9 +1414,9 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 
 /*
  * Create, record, and return a ref_store instance for the specified
- * submodule (or the main repository if submodule is NULL).
+ * gitdir.
  */
-static struct ref_store *ref_store_init(const char *submodule)
+static struct ref_store *ref_store_init(const char *gitdir)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1424,7 +1425,7 @@ static struct ref_store *ref_store_init(const char *submodule)
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(submodule);
+	refs = be->init(gitdir);
 	return refs;
 }
 
@@ -1435,7 +1436,7 @@ struct ref_store *get_main_ref_store(void)
 	if (main_ref_store)
 		return main_ref_store;
 
-	refs = ref_store_init(NULL);
+	refs = ref_store_init(get_git_dir());
 	if (refs) {
 		if (main_ref_store)
 			die("BUG: main_ref_store initialized twice");
@@ -1466,6 +1467,7 @@ struct ref_store *get_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
+	int ret;
 
 	if (!submodule || !*submodule) {
 		return get_main_ref_store();
@@ -1476,8 +1478,14 @@ struct ref_store *get_ref_store(const char *submodule)
 		return refs;
 
 	strbuf_addstr(&submodule_sb, submodule);
-	if (is_nonbare_repository_dir(&submodule_sb))
-		refs = ref_store_init(submodule);
+	ret = is_nonbare_repository_dir(&submodule_sb);
+	strbuf_release(&submodule_sb);
+	if (!ret)
+		return refs;
+
+	ret = submodule_to_gitdir(&submodule_sb, submodule);
+	if (!ret)
+		refs = ref_store_init(submodule_sb.buf);
 	strbuf_release(&submodule_sb);
 
 	if (refs)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index d80c27837..37443369b 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -917,12 +917,6 @@ struct packed_ref_cache {
 struct files_ref_store {
 	struct ref_store base;
 
-	/*
-	 * The name of the submodule represented by this object, or
-	 * NULL if it represents the main repository's reference
-	 * store:
-	 */
-	const char *submodule;
 	char *gitdir;
 	char *gitcommondir;
 	char *packed_refs_path;
@@ -982,22 +976,14 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *submodule)
+static struct ref_store *files_ref_store_create(const char *gitdir)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
-	const char *gitdir = get_git_dir();
 
 	base_ref_store_init(ref_store, &refs_be_files);
 
-	if (submodule) {
-		refs->submodule = xstrdup(submodule);
-		refs->packed_refs_path = git_pathdup_submodule(
-			refs->submodule, "packed-refs");
-		return ref_store;
-	}
-
 	refs->gitdir = xstrdup(gitdir);
 	get_common_dir_noenv(&sb, gitdir);
 	refs->gitcommondir = strbuf_detach(&sb, NULL);
@@ -1014,8 +1000,7 @@ static struct ref_store *files_ref_store_create(const char *submodule)
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	if (refs->submodule)
-		die("BUG: %s called for a submodule", caller);
+	/* This function is to be deleted in the next patch */
 }
 
 /*
@@ -1206,11 +1191,6 @@ static void files_refname_path(struct files_ref_store *refs,
 			       struct strbuf *sb,
 			       const char *refname)
 {
-	if (refs->submodule) {
-		strbuf_git_path_submodule(sb, refs->submodule, "%s", refname);
-		return;
-	}
-
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index f732473e1..dfa181792 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -482,12 +482,11 @@ struct ref_store;
 /* refs backends */
 
 /*
- * Initialize the ref_store for the specified submodule, or for the
- * main repository if submodule == NULL. These functions should call
- * base_ref_store_init() to initialize the shared part of the
- * ref_store and to record the ref_store for later lookup.
+ * Initialize the ref_store for the specified gitdir. These functions
+ * should call base_ref_store_init() to initialize the shared part of
+ * the ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *submodule);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 15/24] refs: move submodule code out of files-backend.c

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> files-backend is now initialized with a $GIT_DIR. Converting a submodule
> path to where real submodule gitdir is located is done in get_ref_store().
> 
> This gives a slight performance improvement for submodules since we
> don't convert submodule path to gitdir at every backend call like
> before. We pay that once at ref-store creation.
> 
> More cleanup in files_downcast() and files_assert_main_repository()
> follows shortly. It's separate to keep noises from this patch.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.c               | 20 ++++++++++++++------
>  refs/files-backend.c | 24 ++----------------------
>  refs/refs-internal.h |  9 ++++-----
>  3 files changed, 20 insertions(+), 33 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index 562834fc0..67acae60c 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -9,6 +9,7 @@
>  #include "refs/refs-internal.h"
>  #include "object.h"
>  #include "tag.h"
> +#include "submodule.h"
>  
>  /*
>   * List of all available backends
> @@ -1413,9 +1414,9 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
>  
>  /*
>   * Create, record, and return a ref_store instance for the specified
> - * submodule (or the main repository if submodule is NULL).
> + * gitdir.
>   */
> -static struct ref_store *ref_store_init(const char *submodule)
> +static struct ref_store *ref_store_init(const char *gitdir)
>  {
>  	const char *be_name = "files";
>  	struct ref_storage_be *be = find_ref_storage_backend(be_name);
> @@ -1424,7 +1425,7 @@ static struct ref_store *ref_store_init(const char *submodule)
>  	if (!be)
>  		die("BUG: reference backend %s is unknown", be_name);
>  
> -	refs = be->init(submodule);
> +	refs = be->init(gitdir);
>  	return refs;
>  }
>  
> @@ -1435,7 +1436,7 @@ struct ref_store *get_main_ref_store(void)
>  	if (main_ref_store)
>  		return main_ref_store;
>  
> -	refs = ref_store_init(NULL);
> +	refs = ref_store_init(get_git_dir());
>  	if (refs) {
>  		if (main_ref_store)
>  			die("BUG: main_ref_store initialized twice");
> @@ -1466,6 +1467,7 @@ struct ref_store *get_ref_store(const char *submodule)
>  {
>  	struct strbuf submodule_sb = STRBUF_INIT;
>  	struct ref_store *refs;
> +	int ret;
>  
>  	if (!submodule || !*submodule) {
>  		return get_main_ref_store();
> @@ -1476,8 +1478,14 @@ struct ref_store *get_ref_store(const char *submodule)
>  		return refs;
>  
>  	strbuf_addstr(&submodule_sb, submodule);
> -	if (is_nonbare_repository_dir(&submodule_sb))
> -		refs = ref_store_init(submodule);
> +	ret = is_nonbare_repository_dir(&submodule_sb);
> +	strbuf_release(&submodule_sb);
> +	if (!ret)
> +		return refs;

`refs` is always NULL here, right? Then it would be more transparent to
return NULL. Or maybe use the `goto cleanup` pattern, which makes it
clearer which are error-handling paths (and lets you get avoid the
temporary variable `ret`)).

> +
> +	ret = submodule_to_gitdir(&submodule_sb, submodule);
> +	if (!ret)
> +		refs = ref_store_init(submodule_sb.buf);
>  	strbuf_release(&submodule_sb);
>  
>  	if (refs)
> diff --git a/refs/files-backend.c b/refs/files-backend.c
> index d80c27837..37443369b 100644
> --- a/refs/files-backend.c
> +++ b/refs/files-backend.c
> @@ -917,12 +917,6 @@ struct packed_ref_cache {
>  struct files_ref_store {
>  	struct ref_store base;
>  
> -	/*
> -	 * The name of the submodule represented by this object, or
> -	 * NULL if it represents the main repository's reference
> -	 * store:
> -	 */
> -	const char *submodule;
>  	char *gitdir;
>  	char *gitcommondir;
>  	char *packed_refs_path;
> @@ -982,22 +976,14 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
>   * Create a new submodule ref cache and add it to the internal
>   * set of caches.
>   */
> -static struct ref_store *files_ref_store_create(const char *submodule)
> +static struct ref_store *files_ref_store_create(const char *gitdir)
>  {
>  	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
>  	struct ref_store *ref_store = (struct ref_store *)refs;
>  	struct strbuf sb = STRBUF_INIT;
> -	const char *gitdir = get_git_dir();
>  
>  	base_ref_store_init(ref_store, &refs_be_files);
>  
> -	if (submodule) {
> -		refs->submodule = xstrdup(submodule);
> -		refs->packed_refs_path = git_pathdup_submodule(
> -			refs->submodule, "packed-refs");
> -		return ref_store;
> -	}
> -
>  	refs->gitdir = xstrdup(gitdir);
>  	get_common_dir_noenv(&sb, gitdir);
>  	refs->gitcommondir = strbuf_detach(&sb, NULL);
> @@ -1014,8 +1000,7 @@ static struct ref_store *files_ref_store_create(const char *submodule)
>  static void files_assert_main_repository(struct files_ref_store *refs,
>  					 const char *caller)
>  {
> -	if (refs->submodule)
> -		die("BUG: %s called for a submodule", caller);
> +	/* This function is to be deleted in the next patch */

I don't think the above comment is correct anymore. Possibly the commit
log message is also out of date too, but I haven't read far enough ahead
to know.

> [...]

Michael

[PATCH v5 16/24] files-backend: replace submodule_allowed check in files_downcast()

[Nguyễn Thái Ngọc Duy]

files-backend.c is unlearning submodules. Instead of having a specific
check for submodules to see what operation is allowed, files backend
now takes a set of flags at init. Each operation will check if the
required flags is present before performing.

For now we have four flags: read, write and odb access. Main ref store
has all flags, obviously, while submodule stores are read-only and have
access to odb (*).

The "main" flag stays because many functions in the backend calls
frontend ones without a ref store, so these functions always target the
main ref store. Ideally the flag should be gone after ref-store-aware
api is in place and used by backends.

(*) Submodule code needs for_each_ref. Try take REF_STORE_ODB flag
out. At least t3404 would fail. The "have access to odb" in submodule is
a bit hacky since we don't know from he whether add_submodule_odb() has
been called.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 15 ++++++---
 refs/files-backend.c | 86 +++++++++++++++++++++++++++++++++-------------------
 refs/refs-internal.h |  9 +++++-
 3 files changed, 73 insertions(+), 37 deletions(-)

diff --git a/refs.c b/refs.c
index 67acae60c..2dc97891a 100644
--- a/refs.c
+++ b/refs.c
@@ -1416,7 +1416,8 @@ static struct ref_store *lookup_submodule_ref_store(const char *submodule)
  * Create, record, and return a ref_store instance for the specified
  * gitdir.
  */
-static struct ref_store *ref_store_init(const char *gitdir)
+static struct ref_store *ref_store_init(const char *gitdir,
+					unsigned int flags)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1425,7 +1426,7 @@ static struct ref_store *ref_store_init(const char *gitdir)
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(gitdir);
+	refs = be->init(gitdir, flags);
 	return refs;
 }
 
@@ -1436,7 +1437,11 @@ struct ref_store *get_main_ref_store(void)
 	if (main_ref_store)
 		return main_ref_store;
 
-	refs = ref_store_init(get_git_dir());
+	refs = ref_store_init(get_git_dir(),
+			      (REF_STORE_READ |
+			       REF_STORE_WRITE |
+			       REF_STORE_ODB |
+			       REF_STORE_MAIN));
 	if (refs) {
 		if (main_ref_store)
 			die("BUG: main_ref_store initialized twice");
@@ -1485,7 +1490,9 @@ struct ref_store *get_ref_store(const char *submodule)
 
 	ret = submodule_to_gitdir(&submodule_sb, submodule);
 	if (!ret)
-		refs = ref_store_init(submodule_sb.buf);
+		/* pretend that add_submodule_odb() has been called */
+		refs = ref_store_init(submodule_sb.buf,
+				      REF_STORE_READ | REF_STORE_ODB);
 	strbuf_release(&submodule_sb);
 
 	if (refs)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 37443369b..474d1027c 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -916,6 +916,7 @@ struct packed_ref_cache {
  */
 struct files_ref_store {
 	struct ref_store base;
+	unsigned int store_flags;
 
 	char *gitdir;
 	char *gitcommondir;
@@ -976,13 +977,15 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *gitdir)
+static struct ref_store *files_ref_store_create(const char *gitdir,
+						unsigned int flags)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
 
 	base_ref_store_init(ref_store, &refs_be_files);
+	refs->store_flags = flags;
 
 	refs->gitdir = xstrdup(gitdir);
 	get_common_dir_noenv(&sb, gitdir);
@@ -994,13 +997,17 @@ static struct ref_store *files_ref_store_create(const char *gitdir)
 }
 
 /*
- * Die if refs is for a submodule (i.e., not for the main repository).
- * caller is used in any necessary error messages.
+ * Die if refs is not the main ref store. caller is used in any
+ * necessary error messages.
  */
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	/* This function is to be deleted in the next patch */
+	if (refs->store_flags & REF_STORE_MAIN)
+		return;
+
+	die("BUG: unallowed operation (%s), only works "
+	    "on main ref store\n", caller);
 }
 
 /*
@@ -1009,9 +1016,9 @@ static void files_assert_main_repository(struct files_ref_store *refs,
  * files_ref_store is for a submodule (i.e., not for the main
  * repository). caller is used in any necessary error messages.
  */
-static struct files_ref_store *files_downcast(
-		struct ref_store *ref_store, int submodule_allowed,
-		const char *caller)
+static struct files_ref_store *files_downcast(struct ref_store *ref_store,
+					      unsigned int required_flags,
+					      const char *caller)
 {
 	struct files_ref_store *refs;
 
@@ -1021,8 +1028,9 @@ static struct files_ref_store *files_downcast(
 
 	refs = (struct files_ref_store *)ref_store;
 
-	if (!submodule_allowed)
-		files_assert_main_repository(refs, caller);
+	if ((refs->store_flags & required_flags) != required_flags)
+		die("BUG: unallowed operation (%s), requires %x, has %x\n",
+		    caller, required_flags, refs->store_flags);
 
 	return refs;
 }
@@ -1404,7 +1412,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "read_raw_ref");
+		files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
 	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
@@ -1821,10 +1829,14 @@ static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
 static int files_peel_ref(struct ref_store *ref_store,
 			  const char *refname, unsigned char *sha1)
 {
-	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
+			       "peel_ref");
 	int flag;
 	unsigned char base[20];
 
+	files_assert_main_repository(refs, "peel_ref");
+
 	if (current_ref_iter && current_ref_iter->refname == refname) {
 		struct object_id peeled;
 
@@ -1929,21 +1941,23 @@ static struct ref_iterator *files_ref_iterator_begin(
 		struct ref_store *ref_store,
 		const char *prefix, unsigned int flags)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "ref_iterator_begin");
+	struct files_ref_store *refs;
 	struct ref_dir *loose_dir, *packed_dir;
 	struct ref_iterator *loose_iter, *packed_iter;
 	struct files_ref_iterator *iter;
 	struct ref_iterator *ref_iterator;
 
-	if (!refs)
-		return empty_ref_iterator_begin();
-
 	if (ref_paranoia < 0)
 		ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
 	if (ref_paranoia)
 		flags |= DO_FOR_EACH_INCLUDE_BROKEN;
 
+	refs = files_downcast(ref_store,
+			      REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB),
+			      "ref_iterator_begin");
+	if (!refs)
+		return empty_ref_iterator_begin();
+
 	iter = xcalloc(1, sizeof(*iter));
 	ref_iterator = &iter->base;
 	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
@@ -2424,7 +2438,8 @@ static void prune_refs(struct ref_to_prune *r)
 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "pack_refs");
+		files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
+			       "pack_refs");
 	struct pack_refs_cb_data cbdata;
 
 	memset(&cbdata, 0, sizeof(cbdata));
@@ -2503,7 +2518,7 @@ static int files_delete_refs(struct ref_store *ref_store,
 			     struct string_list *refnames, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_refs");
+		files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
 	struct strbuf err = STRBUF_INIT;
 	int i, result = 0;
 
@@ -2607,7 +2622,7 @@ static int files_verify_refname_available(struct ref_store *ref_store,
 					  struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "verify_refname_available");
+		files_downcast(ref_store, REF_STORE_READ, "verify_refname_available");
 	struct ref_dir *packed_refs = get_packed_refs(refs);
 	struct ref_dir *loose_refs = get_loose_refs(refs);
 
@@ -2632,7 +2647,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 			    const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "rename_ref");
+		files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
 	unsigned char sha1[20], orig_sha1[20];
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
@@ -2875,7 +2890,7 @@ static int files_create_reflog(struct ref_store *ref_store,
 			       struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_reflog");
+		files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
 	int fd;
 
 	if (log_ref_setup(refs, refname, force_create, &fd, err))
@@ -3119,7 +3134,7 @@ static int files_create_symref(struct ref_store *ref_store,
 			       const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_symref");
+		files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
 	struct strbuf err = STRBUF_INIT;
 	struct ref_lock *lock;
 	int ret;
@@ -3145,7 +3160,9 @@ int set_worktree_head_symref(const char *gitdir, const char *target)
 	 * backends. This function needs to die.
 	 */
 	struct files_ref_store *refs =
-		files_downcast(get_main_ref_store(), 0, "set_head_symref");
+		files_downcast(get_main_ref_store(),
+			       REF_STORE_WRITE,
+			       "set_head_symref");
 
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
@@ -3184,7 +3201,7 @@ static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_exists");
+		files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	int ret;
@@ -3199,7 +3216,7 @@ static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_reflog");
+		files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
 	struct strbuf sb = STRBUF_INIT;
 	int ret;
 
@@ -3254,7 +3271,8 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 					     void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
+		files_downcast(ref_store, REF_STORE_READ,
+			       "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
@@ -3362,7 +3380,8 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "for_each_reflog_ent");
+		files_downcast(ref_store, REF_STORE_READ,
+			       "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
@@ -3450,7 +3469,8 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_iterator_begin");
+		files_downcast(ref_store, REF_STORE_READ,
+			       "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
 	struct strbuf sb = STRBUF_INIT;
@@ -3788,7 +3808,8 @@ static int files_transaction_commit(struct ref_store *ref_store,
 				    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "ref_transaction_commit");
+		files_downcast(ref_store, REF_STORE_WRITE,
+			       "ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
@@ -3993,7 +4014,8 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 					    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "initial_ref_transaction_commit");
+		files_downcast(ref_store, REF_STORE_WRITE,
+			       "initial_ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
@@ -4115,7 +4137,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			       void *policy_cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_expire");
+		files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
@@ -4221,7 +4243,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "init_db");
+		files_downcast(ref_store, REF_STORE_WRITE, "init_db");
 	struct strbuf sb = STRBUF_INIT;
 
 	/*
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index dfa181792..0cca280b5 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -481,12 +481,19 @@ struct ref_store;
 
 /* refs backends */
 
+/* ref_store_init flags */
+#define REF_STORE_READ		(1 << 0)
+#define REF_STORE_WRITE		(1 << 1) /* can perform update operations */
+#define REF_STORE_ODB		(1 << 2) /* has access to object database */
+#define REF_STORE_MAIN		(1 << 3)
+
 /*
  * Initialize the ref_store for the specified gitdir. These functions
  * should call base_ref_store_init() to initialize the shared part of
  * the ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *gitdir);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir,
+					    unsigned int flags);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 16/24] files-backend: replace submodule_allowed check in files_downcast()

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> files-backend.c is unlearning submodules. Instead of having a specific
> check for submodules to see what operation is allowed, files backend
> now takes a set of flags at init. Each operation will check if the
> required flags is present before performing.
> 
> For now we have four flags: read, write and odb access. Main ref store
> has all flags, obviously, while submodule stores are read-only and have
> access to odb (*).

I'm surprised that you have implemented a "read" flag. Do you expect
ever to support ref-stores that are unreadable? In other words, couldn't
"read" just be assumed for any ref store?

> The "main" flag stays because many functions in the backend calls
> frontend ones without a ref store, so these functions always target the
> main ref store. Ideally the flag should be gone after ref-store-aware
> api is in place and used by backends.
> 
> (*) Submodule code needs for_each_ref. Try take REF_STORE_ODB flag
> out. At least t3404 would fail. The "have access to odb" in submodule is
> a bit hacky since we don't know from he whether add_submodule_odb() has
> been called.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.c               | 15 ++++++---
>  refs/files-backend.c | 86 +++++++++++++++++++++++++++++++++-------------------
>  refs/refs-internal.h |  9 +++++-
>  3 files changed, 73 insertions(+), 37 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index 67acae60c..2dc97891a 100644
> --- a/refs.c
> +++ b/refs.c
> [...]
> @@ -1821,10 +1829,14 @@ static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
>  static int files_peel_ref(struct ref_store *ref_store,
>  			  const char *refname, unsigned char *sha1)
>  {
> -	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
> +	struct files_ref_store *refs =
> +		files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
> +			       "peel_ref");
>  	int flag;
>  	unsigned char base[20];
>  
> +	files_assert_main_repository(refs, "peel_ref");

Instead of this call, couldn't you add `REF_STORE_MAIN` to the flags
passed to `files_downcase()`?

> +
>  	if (current_ref_iter && current_ref_iter->refname == refname) {
>  		struct object_id peeled;
>  
> [...]

Michael

[PATCH v5 17/24] refs: rename get_ref_store() to get_submodule_ref_store() and make it public

[Nguyễn Thái Ngọc Duy]

This function is intended to replace *_submodule() refs API. It provides
a ref store for a specific submodule, which can be operated on by a new
set of refs API.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 12 ++++++++----
 refs.h               | 11 +++++++++++
 refs/refs-internal.h | 12 ------------
 3 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/refs.c b/refs.c
index 2dc97891a..7843d3085 100644
--- a/refs.c
+++ b/refs.c
@@ -1171,7 +1171,7 @@ int head_ref(each_ref_fn fn, void *cb_data)
 static int do_for_each_ref(const char *submodule, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(submodule);
+	struct ref_store *refs = get_submodule_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
@@ -1344,10 +1344,10 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
 		/* We need to strip off one or more trailing slashes */
 		char *stripped = xmemdupz(submodule, len);
 
-		refs = get_ref_store(stripped);
+		refs = get_submodule_ref_store(stripped);
 		free(stripped);
 	} else {
-		refs = get_ref_store(submodule);
+		refs = get_submodule_ref_store(submodule);
 	}
 
 	if (!refs)
@@ -1468,13 +1468,17 @@ static void register_submodule_ref_store(struct ref_store *refs,
 		    submodule);
 }
 
-struct ref_store *get_ref_store(const char *submodule)
+struct ref_store *get_submodule_ref_store(const char *submodule)
 {
 	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
 	int ret;
 
 	if (!submodule || !*submodule) {
+		/*
+		 * FIXME: This case is ideally not allowed. But that
+		 * can't happen until we clean up all the callers.
+		 */
 		return get_main_ref_store();
 	}
 
diff --git a/refs.h b/refs.h
index 29013cb7e..2efba6ba9 100644
--- a/refs.h
+++ b/refs.h
@@ -561,5 +561,16 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int ref_storage_backend_exists(const char *name);
 
 struct ref_store *get_main_ref_store(void);
+/*
+ * Return the ref_store instance for the specified submodule. For the
+ * main repository, use submodule==NULL; such a call cannot fail. For
+ * a submodule, the submodule must exist and be a nonbare repository,
+ * otherwise return NULL. If the requested reference store has not yet
+ * been initialized, initialize it first.
+ *
+ * For backwards compatibility, submodule=="" is treated the same as
+ * submodule==NULL.
+ */
+struct ref_store *get_submodule_ref_store(const char *submodule);
 
 #endif /* REFS_H */
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 0cca280b5..f20dde39e 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -646,18 +646,6 @@ struct ref_store {
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-/*
- * Return the ref_store instance for the specified submodule. For the
- * main repository, use submodule==NULL; such a call cannot fail. For
- * a submodule, the submodule must exist and be a nonbare repository,
- * otherwise return NULL. If the requested reference store has not yet
- * been initialized, initialize it first.
- *
- * For backwards compatibility, submodule=="" is treated the same as
- * submodule==NULL.
- */
-struct ref_store *get_ref_store(const char *submodule);
-
 const char *resolve_ref_recursively(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
-- 
2.11.0.157.gd943d85

[PATCH v5 18/24] refs: add new ref-store api

[Nguyễn Thái Ngọc Duy]

This is not meant to cover all existing API. It adds enough to test ref
stores with the new test program test-ref-store, coming soon and to be
used by files-backend.c.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 235 +++++++++++++++++++++++++++++++++++++--------------
 refs.h               |  71 ++++++++++++++++
 refs/files-backend.c |  13 +--
 refs/refs-internal.h |  31 +------
 4 files changed, 253 insertions(+), 97 deletions(-)

diff --git a/refs.c b/refs.c
index 7843d3085..9137ac283 100644
--- a/refs.c
+++ b/refs.c
@@ -185,13 +185,20 @@ struct ref_filter {
 	void *cb_data;
 };
 
-int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
+int refs_read_ref_full(struct ref_store *refs, const char *refname,
+		       int resolve_flags, unsigned char *sha1, int *flags)
 {
-	if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
+	if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
 		return 0;
 	return -1;
 }
 
+int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
+{
+	return refs_read_ref_full(get_main_ref_store(), refname,
+				  resolve_flags, sha1, flags);
+}
+
 int read_ref(const char *refname, unsigned char *sha1)
 {
 	return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
@@ -286,34 +293,52 @@ void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_li
 	for_each_rawref(warn_if_dangling_symref, &data);
 }
 
+int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
+}
+
 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in("refs/tags/", fn, cb_data);
+	return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
+	return refs_for_each_tag_ref(get_submodule_ref_store(submodule),
+				     fn, cb_data);
+}
+
+int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 }
 
 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in("refs/heads/", fn, cb_data);
+	return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
+	return refs_for_each_branch_ref(get_submodule_ref_store(submodule),
+					fn, cb_data);
+}
+
+int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 }
 
 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in("refs/remotes/", fn, cb_data);
+	return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
+	return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
+					fn, cb_data);
 }
 
 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
@@ -1120,14 +1145,17 @@ const char *find_descendant_ref(const char *dirname,
 	return NULL;
 }
 
-int rename_ref_available(const char *old_refname, const char *new_refname)
+int refs_rename_ref_available(struct ref_store *refs,
+			      const char *old_refname,
+			      const char *new_refname)
 {
 	struct string_list skip = STRING_LIST_INIT_NODUP;
 	struct strbuf err = STRBUF_INIT;
 	int ok;
 
 	string_list_insert(&skip, old_refname);
-	ok = !verify_refname_available(new_refname, NULL, &skip, &err);
+	ok = !refs_verify_refname_available(refs, new_refname,
+					    NULL, &skip, &err);
 	if (!ok)
 		error("%s", err.buf);
 
@@ -1168,10 +1196,9 @@ int head_ref(each_ref_fn fn, void *cb_data)
  * non-zero value, stop the iteration and return that value;
  * otherwise, return 0.
  */
-static int do_for_each_ref(const char *submodule, const char *prefix,
+static int do_for_each_ref(struct ref_store *refs, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_submodule_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
@@ -1183,19 +1210,30 @@ static int do_for_each_ref(const char *submodule, const char *prefix,
 	return do_for_each_ref_iterator(iter, fn, cb_data);
 }
 
+int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
+}
+
 int for_each_ref(each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
+	return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
+	return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
+}
+
+int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
+			 each_ref_fn fn, void *cb_data)
+{
+	return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
 }
 
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
+	return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
 }
 
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
@@ -1204,19 +1242,23 @@ int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsig
 
 	if (broken)
 		flag = DO_FOR_EACH_INCLUDE_BROKEN;
-	return do_for_each_ref(NULL, prefix, fn, 0, flag, cb_data);
+	return do_for_each_ref(get_main_ref_store(),
+			       prefix, fn, 0, flag, cb_data);
 }
 
 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
-		each_ref_fn fn, void *cb_data)
+			      each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
+	return refs_for_each_ref_in(get_submodule_ref_store(submodule),
+				    prefix, fn, cb_data);
 }
 
 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, git_replace_ref_base, fn,
-			       strlen(git_replace_ref_base), 0, cb_data);
+	return do_for_each_ref(get_main_ref_store(),
+			       git_replace_ref_base, fn,
+			       strlen(git_replace_ref_base),
+			       0, cb_data);
 }
 
 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
@@ -1224,19 +1266,25 @@ int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
 	struct strbuf buf = STRBUF_INIT;
 	int ret;
 	strbuf_addf(&buf, "%srefs/", get_git_namespace());
-	ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
+	ret = do_for_each_ref(get_main_ref_store(),
+			      buf.buf, fn, 0, 0, cb_data);
 	strbuf_release(&buf);
 	return ret;
 }
 
-int for_each_rawref(each_ref_fn fn, void *cb_data)
+int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, "", fn, 0,
+	return do_for_each_ref(refs, "", fn, 0,
 			       DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 }
 
+int for_each_rawref(each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
+}
+
 /* This function needs to return a meaningful errno on failure */
-const char *resolve_ref_recursively(struct ref_store *refs,
+const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
 				    unsigned char *sha1, int *flags)
@@ -1323,7 +1371,7 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_main_ref_store(), refname,
+	return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1353,7 +1401,7 @@ int resolve_gitlink_ref(const char *submodule, const char *refname,
 	if (!refs)
 		return -1;
 
-	if (!resolve_ref_recursively(refs, refname, 0, sha1, &flags) ||
+	if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
 	    is_null_sha1(sha1))
 		return -1;
 	return 0;
@@ -1511,27 +1559,42 @@ void base_ref_store_init(struct ref_store *refs,
 }
 
 /* backend functions */
+int refs_pack_refs(struct ref_store *refs, unsigned int flags)
+{
+	return refs->be->pack_refs(refs, flags);
+}
+
 int pack_refs(unsigned int flags)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_pack_refs(get_main_ref_store(), flags);
+}
 
-	return refs->be->pack_refs(refs, flags);
+int refs_peel_ref(struct ref_store *refs, const char *refname,
+		  unsigned char *sha1)
+{
+	return refs->be->peel_ref(refs, refname, sha1);
 }
 
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_peel_ref(get_main_ref_store(), refname, sha1);
+}
 
-	return refs->be->peel_ref(refs, refname, sha1);
+int refs_create_symref(struct ref_store *refs,
+		       const char *ref_target,
+		       const char *refs_heads_master,
+		       const char *logmsg)
+{
+	return refs->be->create_symref(refs, ref_target,
+				       refs_heads_master,
+				       logmsg);
 }
 
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_main_ref_store();
-
-	return refs->be->create_symref(refs, ref_target, refs_heads_master,
-				       logmsg);
+	return refs_create_symref(get_main_ref_store(), ref_target,
+				  refs_heads_master, logmsg);
 }
 
 int ref_transaction_commit(struct ref_transaction *transaction,
@@ -1542,19 +1605,17 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	return refs->be->transaction_commit(refs, transaction, err);
 }
 
-int verify_refname_available(const char *refname,
-			     const struct string_list *extra,
-			     const struct string_list *skip,
-			     struct strbuf *err)
+int refs_verify_refname_available(struct ref_store *refs,
+				  const char *refname,
+				  const struct string_list *extra,
+				  const struct string_list *skip,
+				  struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
-
 	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
 }
 
-int for_each_reflog(each_ref_fn fn, void *cb_data)
+int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_main_ref_store();
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1562,43 +1623,84 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 	return do_for_each_ref_iterator(iter, fn, cb_data);
 }
 
-int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
-				void *cb_data)
+int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
+}
 
+int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
+				     const char *refname,
+				     each_reflog_ent_fn fn,
+				     void *cb_data)
+{
 	return refs->be->for_each_reflog_ent_reverse(refs, refname,
 						     fn, cb_data);
 }
 
+int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
+				void *cb_data)
+{
+	return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
+						refname, fn, cb_data);
+}
+
+int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
+			     each_reflog_ent_fn fn, void *cb_data)
+{
+	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
+}
+
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_for_each_reflog_ent(get_main_ref_store(), refname,
+					fn, cb_data);
+}
 
-	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
+int refs_reflog_exists(struct ref_store *refs, const char *refname)
+{
+	return refs->be->reflog_exists(refs, refname);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_reflog_exists(get_main_ref_store(), refname);
+}
 
-	return refs->be->reflog_exists(refs, refname);
+int refs_create_reflog(struct ref_store *refs, const char *refname,
+		       int force_create, struct strbuf *err)
+{
+	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_create_reflog(get_main_ref_store(), refname,
+				  force_create, err);
+}
 
-	return refs->be->create_reflog(refs, refname, force_create, err);
+int refs_delete_reflog(struct ref_store *refs, const char *refname)
+{
+	return refs->be->delete_reflog(refs, refname);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_delete_reflog(get_main_ref_store(), refname);
+}
 
-	return refs->be->delete_reflog(refs, refname);
+int refs_reflog_expire(struct ref_store *refs,
+		       const char *refname, const unsigned char *sha1,
+		       unsigned int flags,
+		       reflog_expiry_prepare_fn prepare_fn,
+		       reflog_expiry_should_prune_fn should_prune_fn,
+		       reflog_expiry_cleanup_fn cleanup_fn,
+		       void *policy_cb_data)
+{
+	return refs->be->reflog_expire(refs, refname, sha1, flags,
+				       prepare_fn, should_prune_fn,
+				       cleanup_fn, policy_cb_data);
 }
 
 int reflog_expire(const char *refname, const unsigned char *sha1,
@@ -1608,11 +1710,10 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_main_ref_store();
-
-	return refs->be->reflog_expire(refs, refname, sha1, flags,
-				       prepare_fn, should_prune_fn,
-				       cleanup_fn, policy_cb_data);
+	return refs_reflog_expire(get_main_ref_store(),
+				  refname, sha1, flags,
+				  prepare_fn, should_prune_fn,
+				  cleanup_fn, policy_cb_data);
 }
 
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
@@ -1623,16 +1724,24 @@ int initial_ref_transaction_commit(struct ref_transaction *transaction,
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
-int delete_refs(struct string_list *refnames, unsigned int flags)
+int refs_delete_refs(struct ref_store *refs, struct string_list *refnames,
+		     unsigned int flags)
 {
-	struct ref_store *refs = get_main_ref_store();
-
 	return refs->be->delete_refs(refs, refnames, flags);
 }
 
-int rename_ref(const char *oldref, const char *newref, const char *logmsg)
+int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_main_ref_store();
+	return refs_delete_refs(get_main_ref_store(), refnames, flags);
+}
 
+int refs_rename_ref(struct ref_store *refs, const char *oldref,
+		    const char *newref, const char *logmsg)
+{
 	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
+
+int rename_ref(const char *oldref, const char *newref, const char *logmsg)
+{
+	return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
+}
diff --git a/refs.h b/refs.h
index 2efba6ba9..70d4eb87c 100644
--- a/refs.h
+++ b/refs.h
@@ -58,16 +58,47 @@ struct string_list;
 #define RESOLVE_REF_NO_RECURSE 0x02
 #define RESOLVE_REF_ALLOW_BAD_NAME 0x04
 
+const char *refs_resolve_ref_unsafe(struct ref_store *refs,
+				    const char *refname,
+				    int resolve_flags,
+				    unsigned char *sha1,
+				    int *flags);
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags);
 
 char *resolve_refdup(const char *refname, int resolve_flags,
 		     unsigned char *sha1, int *flags);
 
+int refs_read_ref_full(struct ref_store *refs, const char *refname,
+		       int resolve_flags, unsigned char *sha1, int *flags);
 int read_ref_full(const char *refname, int resolve_flags,
 		  unsigned char *sha1, int *flags);
 int read_ref(const char *refname, unsigned char *sha1);
 
+/*
+ * Return 0 if a reference named refname could be created without
+ * conflicting with the name of an existing reference. Otherwise,
+ * return a negative value and write an explanation to err. If extras
+ * is non-NULL, it is a list of additional refnames with which refname
+ * is not allowed to conflict. If skip is non-NULL, ignore potential
+ * conflicts with refs in skip (e.g., because they are scheduled for
+ * deletion in the same operation). Behavior is undefined if the same
+ * name is listed in both extras and skip.
+ *
+ * Two reference names conflict if one of them exactly matches the
+ * leading components of the other; e.g., "foo/bar" conflicts with
+ * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
+ * "foo/barbados".
+ *
+ * extras and skip must be sorted.
+ */
+
+int refs_verify_refname_available(struct ref_store *refs,
+				  const char *refname,
+				  const struct string_list *extra,
+				  const struct string_list *skip,
+				  struct strbuf *err);
+
 int ref_exists(const char *refname);
 
 int should_autocreate_reflog(const char *refname);
@@ -84,6 +115,8 @@ extern int refs_init_db(struct strbuf *err);
  * Symbolic references are considered unpeelable, even if they
  * ultimately resolve to a peelable tag.
  */
+int refs_peel_ref(struct ref_store *refs, const char *refname,
+		  unsigned char *sha1);
 int peel_ref(const char *refname, unsigned char *sha1);
 
 /**
@@ -196,6 +229,17 @@ typedef int each_ref_fn(const char *refname,
  * modifies the reference also returns a nonzero value to immediately
  * stop the iteration.
  */
+int refs_for_each_ref(struct ref_store *refs,
+		      each_ref_fn fn, void *cb_data);
+int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
+			 each_ref_fn fn, void *cb_data);
+int refs_for_each_tag_ref(struct ref_store *refs,
+			  each_ref_fn fn, void *cb_data);
+int refs_for_each_branch_ref(struct ref_store *refs,
+			     each_ref_fn fn, void *cb_data);
+int refs_for_each_remote_ref(struct ref_store *refs,
+			     each_ref_fn fn, void *cb_data);
+
 int head_ref(each_ref_fn fn, void *cb_data);
 int for_each_ref(each_ref_fn fn, void *cb_data);
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
@@ -225,6 +269,7 @@ int head_ref_namespaced(each_ref_fn fn, void *cb_data);
 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
 
 /* can be used to learn about broken ref and symref */
+int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data);
 int for_each_rawref(each_ref_fn fn, void *cb_data);
 
 static inline const char *has_glob_specials(const char *pattern)
@@ -248,6 +293,7 @@ void warn_dangling_symrefs(FILE *fp, const char *msg_fmt,
  * Write a packed-refs file for the current repository.
  * flags: Combination of the above PACK_REFS_* flags.
  */
+int refs_pack_refs(struct ref_store *refs, unsigned int flags);
 int pack_refs(unsigned int flags);
 
 /*
@@ -263,6 +309,8 @@ int pack_refs(unsigned int flags);
 /*
  * Setup reflog before using. Fill in err and return -1 on failure.
  */
+int refs_create_reflog(struct ref_store *refs, const char *refname,
+		       int force_create, struct strbuf *err);
 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err);
 
 /** Reads log for the value of ref during at_time. **/
@@ -272,6 +320,7 @@ int read_ref_at(const char *refname, unsigned int flags,
 		unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
 
 /** Check if a particular reflog exists */
+int refs_reflog_exists(struct ref_store *refs, const char *refname);
 int reflog_exists(const char *refname);
 
 /*
@@ -290,9 +339,12 @@ int delete_ref(const char *refname, const unsigned char *old_sha1,
  * an all-or-nothing transaction). flags is passed through to
  * ref_transaction_delete().
  */
+int refs_delete_refs(struct ref_store *refs, struct string_list *refnames,
+		     unsigned int flags);
 int delete_refs(struct string_list *refnames, unsigned int flags);
 
 /** Delete a reflog */
+int refs_delete_reflog(struct ref_store *refs, const char *refname);
 int delete_reflog(const char *refname);
 
 /* iterate over reflog entries */
@@ -301,6 +353,12 @@ typedef int each_reflog_ent_fn(
 		const char *committer, unsigned long timestamp,
 		int tz, const char *msg, void *cb_data);
 
+int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
+			     each_reflog_ent_fn fn, void *cb_data);
+int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
+				     const char *refname,
+				     each_reflog_ent_fn fn,
+				     void *cb_data);
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 
@@ -308,6 +366,7 @@ int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void
  * Calls the specified function for each reflog file until it returns nonzero,
  * and returns the value
  */
+int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data);
 int for_each_reflog(each_ref_fn fn, void *cb_data);
 
 #define REFNAME_ALLOW_ONELEVEL 1
@@ -328,8 +387,12 @@ const char *prettify_refname(const char *refname);
 char *shorten_unambiguous_ref(const char *refname, int strict);
 
 /** rename ref, return 0 on success **/
+int refs_rename_ref(struct ref_store *refs, const char *oldref,
+		    const char *newref, const char *logmsg);
 int rename_ref(const char *oldref, const char *newref, const char *logmsg);
 
+int refs_create_symref(struct ref_store *refs, const char *refname,
+		       const char *target, const char *logmsg);
 int create_symref(const char *refname, const char *target, const char *logmsg);
 
 /*
@@ -551,6 +614,14 @@ typedef void reflog_expiry_cleanup_fn(void *cb_data);
  * enum expire_reflog_flags. The three function pointers are described
  * above. On success, return zero.
  */
+int refs_reflog_expire(struct ref_store *refs,
+		       const char *refname,
+		       const unsigned char *sha1,
+		       unsigned int flags,
+		       reflog_expiry_prepare_fn prepare_fn,
+		       reflog_expiry_should_prune_fn should_prune_fn,
+		       reflog_expiry_cleanup_fn cleanup_fn,
+		       void *policy_cb_data);
 int reflog_expire(const char *refname, const unsigned char *sha1,
 		  unsigned int flags,
 		  reflog_expiry_prepare_fn prepare_fn,
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 474d1027c..dafddefd3 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1320,7 +1320,7 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 					 create_dir_entry(refs, refname.buf,
 							  refname.len, 1));
 		} else {
-			if (!resolve_ref_recursively(&refs->base,
+			if (!refs_resolve_ref_unsafe(&refs->base,
 						     refname.buf,
 						     RESOLVE_REF_READING,
 						     sha1, &flag)) {
@@ -1629,7 +1629,8 @@ static int lock_raw_ref(struct files_ref_store *refs,
 		 * another reference such as "refs/foo". There is no
 		 * reason to expect this error to be transitory.
 		 */
-		if (verify_refname_available(refname, extras, skip, err)) {
+		if (refs_verify_refname_available(&refs->base, refname,
+						  extras, skip, err)) {
 			if (mustexist) {
 				/*
 				 * To the user the relevant error is
@@ -2671,7 +2672,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (flag & REF_ISSYMREF)
 		return error("refname %s is a symbolic ref, renaming it is not supported",
 			oldrefname);
-	if (!rename_ref_available(oldrefname, newrefname))
+	if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname))
 		return 1;
 
 	files_reflog_path(refs, &sb_oldref, oldrefname);
@@ -4055,9 +4056,9 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 		if ((update->flags & REF_HAVE_OLD) &&
 		    !is_null_sha1(update->old_sha1))
 			die("BUG: initial ref transaction with old_sha1 set");
-		if (verify_refname_available(update->refname,
-					     &affected_refnames, NULL,
-					     err)) {
+		if (refs_verify_refname_available(&refs->base, update->refname,
+						  &affected_refnames, NULL,
+						  err)) {
 			ret = TRANSACTION_NAME_CONFLICT;
 			goto cleanup;
 		}
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index f20dde39e..5f26208c2 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -112,28 +112,6 @@ enum peel_status {
 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1);
 
 /*
- * Return 0 if a reference named refname could be created without
- * conflicting with the name of an existing reference. Otherwise,
- * return a negative value and write an explanation to err. If extras
- * is non-NULL, it is a list of additional refnames with which refname
- * is not allowed to conflict. If skip is non-NULL, ignore potential
- * conflicts with refs in skip (e.g., because they are scheduled for
- * deletion in the same operation). Behavior is undefined if the same
- * name is listed in both extras and skip.
- *
- * Two reference names conflict if one of them exactly matches the
- * leading components of the other; e.g., "foo/bar" conflicts with
- * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
- * "foo/barbados".
- *
- * extras and skip must be sorted.
- */
-int verify_refname_available(const char *newname,
-			     const struct string_list *extras,
-			     const struct string_list *skip,
-			     struct strbuf *err);
-
-/*
  * Copy the reflog message msg to buf, which has been allocated sufficiently
  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
  * because reflog file is one line per entry.
@@ -252,7 +230,9 @@ const char *find_descendant_ref(const char *dirname,
  * processes (though rename_ref() catches some races that might get by
  * this check).
  */
-int rename_ref_available(const char *old_refname, const char *new_refname);
+int refs_rename_ref_available(struct ref_store *refs,
+			      const char *old_refname,
+			      const char *new_refname);
 
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define SYMREF_MAXDEPTH 5
@@ -646,9 +626,4 @@ struct ref_store {
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-const char *resolve_ref_recursively(struct ref_store *refs,
-				    const char *refname,
-				    int resolve_flags,
-				    unsigned char *sha1, int *flags);
-
 #endif /* REFS_REFS_INTERNAL_H */
-- 
2.11.0.157.gd943d85

[PATCH v5 19/24] refs: new transaction related ref-store api

[Nguyễn Thái Ngọc Duy]

The transaction struct now takes a ref store at creation and will
operate on that ref store alone.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs.c               | 54 ++++++++++++++++++++++++++++++++++++++++------------
 refs.h               |  8 ++++++++
 refs/refs-internal.h |  1 +
 3 files changed, 51 insertions(+), 12 deletions(-)

diff --git a/refs.c b/refs.c
index 9137ac283..851b5e125 100644
--- a/refs.c
+++ b/refs.c
@@ -618,16 +618,19 @@ static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1
 	return 0;
 }
 
-int delete_ref(const char *refname, const unsigned char *old_sha1,
-	       unsigned int flags)
+int refs_delete_ref(struct ref_store *refs, const char *refname,
+		    const unsigned char *old_sha1,
+		    unsigned int flags)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF)
+	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
+		assert(refs == get_main_ref_store());
 		return delete_pseudoref(refname, old_sha1);
+	}
 
-	transaction = ref_transaction_begin(&err);
+	transaction = ref_store_transaction_begin(refs, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, refname, old_sha1,
 				   flags, NULL, &err) ||
@@ -642,6 +645,13 @@ int delete_ref(const char *refname, const unsigned char *old_sha1,
 	return 0;
 }
 
+int delete_ref(const char *refname, const unsigned char *old_sha1,
+	       unsigned int flags)
+{
+	return refs_delete_ref(get_main_ref_store(), refname,
+			       old_sha1, flags);
+}
+
 int copy_reflog_msg(char *buf, const char *msg)
 {
 	char *cp = buf;
@@ -801,11 +811,20 @@ int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time,
 	return 1;
 }
 
-struct ref_transaction *ref_transaction_begin(struct strbuf *err)
+struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
+						    struct strbuf *err)
 {
+	struct ref_transaction *tr;
 	assert(err);
 
-	return xcalloc(1, sizeof(struct ref_transaction));
+	tr = xcalloc(1, sizeof(struct ref_transaction));
+	tr->ref_store = refs;
+	return tr;
+}
+
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
+{
+	return ref_store_transaction_begin(get_main_ref_store(), err);
 }
 
 void ref_transaction_free(struct ref_transaction *transaction)
@@ -922,18 +941,20 @@ int update_ref_oid(const char *msg, const char *refname,
 		old_oid ? old_oid->hash : NULL, flags, onerr);
 }
 
-int update_ref(const char *msg, const char *refname,
-	       const unsigned char *new_sha1, const unsigned char *old_sha1,
-	       unsigned int flags, enum action_on_err onerr)
+int refs_update_ref(struct ref_store *refs, const char *msg,
+		    const char *refname, const unsigned char *new_sha1,
+		    const unsigned char *old_sha1, unsigned int flags,
+		    enum action_on_err onerr)
 {
 	struct ref_transaction *t = NULL;
 	struct strbuf err = STRBUF_INIT;
 	int ret = 0;
 
 	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
+		assert(refs == get_main_ref_store());
 		ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 	} else {
-		t = ref_transaction_begin(&err);
+		t = ref_store_transaction_begin(refs, &err);
 		if (!t ||
 		    ref_transaction_update(t, refname, new_sha1, old_sha1,
 					   flags, msg, &err) ||
@@ -964,6 +985,15 @@ int update_ref(const char *msg, const char *refname,
 	return 0;
 }
 
+int update_ref(const char *msg, const char *refname,
+	       const unsigned char *new_sha1,
+	       const unsigned char *old_sha1,
+	       unsigned int flags, enum action_on_err onerr)
+{
+	return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
+			       old_sha1, flags, onerr);
+}
+
 char *shorten_unambiguous_ref(const char *refname, int strict)
 {
 	int i;
@@ -1600,7 +1630,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
+	struct ref_store *refs = transaction->ref_store;
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
@@ -1719,7 +1749,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
+	struct ref_store *refs = transaction->ref_store;
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
diff --git a/refs.h b/refs.h
index 70d4eb87c..342cecd23 100644
--- a/refs.h
+++ b/refs.h
@@ -330,6 +330,9 @@ int reflog_exists(const char *refname);
  * exists, regardless of its old value. It is an error for old_sha1 to
  * be NULL_SHA1. flags is passed through to ref_transaction_delete().
  */
+int refs_delete_ref(struct ref_store *refs, const char *refname,
+		    const unsigned char *old_sha1,
+		    unsigned int flags);
 int delete_ref(const char *refname, const unsigned char *old_sha1,
 	       unsigned int flags);
 
@@ -414,6 +417,8 @@ enum action_on_err {
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
+struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
+						    struct strbuf *err);
 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
@@ -548,6 +553,9 @@ void ref_transaction_free(struct ref_transaction *transaction);
  * ref_transaction_update(). Handle errors as requested by the `onerr`
  * argument.
  */
+int refs_update_ref(struct ref_store *refs, const char *msg, const char *refname,
+		    const unsigned char *new_sha1, const unsigned char *old_sha1,
+		    unsigned int flags, enum action_on_err onerr);
 int update_ref(const char *msg, const char *refname,
 	       const unsigned char *new_sha1, const unsigned char *old_sha1,
 	       unsigned int flags, enum action_on_err onerr);
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 5f26208c2..690498698 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -200,6 +200,7 @@ enum ref_transaction_state {
  * as atomically as possible.  This structure is opaque to callers.
  */
 struct ref_transaction {
+	struct ref_store *ref_store;
 	struct ref_update **updates;
 	size_t alloc;
 	size_t nr;
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 19/24] refs: new transaction related ref-store api

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> The transaction struct now takes a ref store at creation and will
> operate on that ref store alone.
> 
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  refs.c               | 54 ++++++++++++++++++++++++++++++++++++++++------------
>  refs.h               |  8 ++++++++
>  refs/refs-internal.h |  1 +
>  3 files changed, 51 insertions(+), 12 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index 9137ac283..851b5e125 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -618,16 +618,19 @@ static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1
>  	return 0;
>  }
>  
> -int delete_ref(const char *refname, const unsigned char *old_sha1,
> -	       unsigned int flags)
> +int refs_delete_ref(struct ref_store *refs, const char *refname,
> +		    const unsigned char *old_sha1,
> +		    unsigned int flags)
>  {
>  	struct ref_transaction *transaction;
>  	struct strbuf err = STRBUF_INIT;
>  
> -	if (ref_type(refname) == REF_TYPE_PSEUDOREF)
> +	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
> +		assert(refs == get_main_ref_store());

Hmmm, I would have expected this to be checked via `(refs.flags &
REF_STORE_MAIN)`. I guess this is temporary; once we have compound ref
stores either version will need to be changed again. So I don't see a
strong argument for one vs. the other.

It might be more natural to make `delete_pseudoref()` take a `refs`
argument and do the check internally.

(Same comments below where `write_pseudoref()` is called.)

Michael

>  		return delete_pseudoref(refname, old_sha1);
> +	}
>  
> -	transaction = ref_transaction_begin(&err);
> +	transaction = ref_store_transaction_begin(refs, &err);
>  	if (!transaction ||
>  	    ref_transaction_delete(transaction, refname, old_sha1,
>  				   flags, NULL, &err) ||
> @@ -642,6 +645,13 @@ int delete_ref(const char *refname, const unsigned char *old_sha1,
>  	return 0;
>  }
>  
> +int delete_ref(const char *refname, const unsigned char *old_sha1,
> +	       unsigned int flags)
> +{
> +	return refs_delete_ref(get_main_ref_store(), refname,
> +			       old_sha1, flags);
> +}
> +
>  int copy_reflog_msg(char *buf, const char *msg)
>  {
>  	char *cp = buf;
> @@ -801,11 +811,20 @@ int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time,
>  	return 1;
>  }
>  
> -struct ref_transaction *ref_transaction_begin(struct strbuf *err)
> +struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
> +						    struct strbuf *err)
>  {
> +	struct ref_transaction *tr;
>  	assert(err);
>  
> -	return xcalloc(1, sizeof(struct ref_transaction));
> +	tr = xcalloc(1, sizeof(struct ref_transaction));
> +	tr->ref_store = refs;
> +	return tr;
> +}
> +
> +struct ref_transaction *ref_transaction_begin(struct strbuf *err)
> +{
> +	return ref_store_transaction_begin(get_main_ref_store(), err);
>  }
>  
>  void ref_transaction_free(struct ref_transaction *transaction)
> @@ -922,18 +941,20 @@ int update_ref_oid(const char *msg, const char *refname,
>  		old_oid ? old_oid->hash : NULL, flags, onerr);
>  }
>  
> -int update_ref(const char *msg, const char *refname,
> -	       const unsigned char *new_sha1, const unsigned char *old_sha1,
> -	       unsigned int flags, enum action_on_err onerr)
> +int refs_update_ref(struct ref_store *refs, const char *msg,
> +		    const char *refname, const unsigned char *new_sha1,
> +		    const unsigned char *old_sha1, unsigned int flags,
> +		    enum action_on_err onerr)
>  {
>  	struct ref_transaction *t = NULL;
>  	struct strbuf err = STRBUF_INIT;
>  	int ret = 0;
>  
>  	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
> +		assert(refs == get_main_ref_store());
>  		ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
>  	} else {
> -		t = ref_transaction_begin(&err);
> +		t = ref_store_transaction_begin(refs, &err);
>  		if (!t ||
>  		    ref_transaction_update(t, refname, new_sha1, old_sha1,
>  					   flags, msg, &err) ||
> @@ -964,6 +985,15 @@ int update_ref(const char *msg, const char *refname,
>  	return 0;
>  }
>  
> +int update_ref(const char *msg, const char *refname,
> +	       const unsigned char *new_sha1,
> +	       const unsigned char *old_sha1,
> +	       unsigned int flags, enum action_on_err onerr)
> +{
> +	return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
> +			       old_sha1, flags, onerr);
> +}
> +
>  char *shorten_unambiguous_ref(const char *refname, int strict)
>  {
>  	int i;
> @@ -1600,7 +1630,7 @@ int create_symref(const char *ref_target, const char *refs_heads_master,
>  int ref_transaction_commit(struct ref_transaction *transaction,
>  			   struct strbuf *err)
>  {
> -	struct ref_store *refs = get_main_ref_store();
> +	struct ref_store *refs = transaction->ref_store;
>  
>  	return refs->be->transaction_commit(refs, transaction, err);
>  }
> @@ -1719,7 +1749,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
>  int initial_ref_transaction_commit(struct ref_transaction *transaction,
>  				   struct strbuf *err)
>  {
> -	struct ref_store *refs = get_main_ref_store();
> +	struct ref_store *refs = transaction->ref_store;
>  
>  	return refs->be->initial_transaction_commit(refs, transaction, err);
>  }
> diff --git a/refs.h b/refs.h
> index 70d4eb87c..342cecd23 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -330,6 +330,9 @@ int reflog_exists(const char *refname);
>   * exists, regardless of its old value. It is an error for old_sha1 to
>   * be NULL_SHA1. flags is passed through to ref_transaction_delete().
>   */
> +int refs_delete_ref(struct ref_store *refs, const char *refname,
> +		    const unsigned char *old_sha1,
> +		    unsigned int flags);
>  int delete_ref(const char *refname, const unsigned char *old_sha1,
>  	       unsigned int flags);
>  
> @@ -414,6 +417,8 @@ enum action_on_err {
>   * Begin a reference transaction.  The reference transaction must
>   * be freed by calling ref_transaction_free().
>   */
> +struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
> +						    struct strbuf *err);
>  struct ref_transaction *ref_transaction_begin(struct strbuf *err);
>  
>  /*
> @@ -548,6 +553,9 @@ void ref_transaction_free(struct ref_transaction *transaction);
>   * ref_transaction_update(). Handle errors as requested by the `onerr`
>   * argument.
>   */
> +int refs_update_ref(struct ref_store *refs, const char *msg, const char *refname,
> +		    const unsigned char *new_sha1, const unsigned char *old_sha1,
> +		    unsigned int flags, enum action_on_err onerr);
>  int update_ref(const char *msg, const char *refname,
>  	       const unsigned char *new_sha1, const unsigned char *old_sha1,
>  	       unsigned int flags, enum action_on_err onerr);
> diff --git a/refs/refs-internal.h b/refs/refs-internal.h
> index 5f26208c2..690498698 100644
> --- a/refs/refs-internal.h
> +++ b/refs/refs-internal.h
> @@ -200,6 +200,7 @@ enum ref_transaction_state {
>   * as atomically as possible.  This structure is opaque to callers.
>   */
>  struct ref_transaction {
> +	struct ref_store *ref_store;
>  	struct ref_update **updates;
>  	size_t alloc;
>  	size_t nr;
> 

[PATCH v5 20/24] files-backend: avoid ref api targetting main ref store

[Nguyễn Thái Ngọc Duy]

A small step towards making files-backend works as a non-main ref store
using the newly added store-aware API.

For the record, `join` and `nm` on refs.o and files-backend.o tell me
that files-backend no longer uses functions that defaults to
get_main_ref_store().

I'm not yet comfortable at the idea of removing
files_assert_main_repository() (or converting REF_STORE_MAIN to
REF_STORE_WRITE). More staring and testing is required before that can
happen. Well, except peel_ref(). I'm pretty sure that function is safe.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 refs/files-backend.c | 85 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 49 insertions(+), 36 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index dafddefd3..09c280fd3 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1836,8 +1836,6 @@ static int files_peel_ref(struct ref_store *ref_store,
 	int flag;
 	unsigned char base[20];
 
-	files_assert_main_repository(refs, "peel_ref");
-
 	if (current_ref_iter && current_ref_iter->refname == refname) {
 		struct object_id peeled;
 
@@ -1847,7 +1845,8 @@ static int files_peel_ref(struct ref_store *ref_store,
 		return 0;
 	}
 
-	if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
+	if (refs_read_ref_full(ref_store, refname,
+			       RESOLVE_REF_READING, base, &flag))
 		return -1;
 
 	/*
@@ -2017,15 +2016,15 @@ static struct ref_iterator *files_ref_iterator_begin(
  * on success. On error, write an error message to err, set errno, and
  * return a negative value.
  */
-static int verify_lock(struct ref_lock *lock,
+static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
 		       const unsigned char *old_sha1, int mustexist,
 		       struct strbuf *err)
 {
 	assert(err);
 
-	if (read_ref_full(lock->ref_name,
-			  mustexist ? RESOLVE_REF_READING : 0,
-			  lock->old_oid.hash, NULL)) {
+	if (refs_read_ref_full(ref_store, lock->ref_name,
+			       mustexist ? RESOLVE_REF_READING : 0,
+			       lock->old_oid.hash, NULL)) {
 		if (old_sha1) {
 			int save_errno = errno;
 			strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
@@ -2094,8 +2093,9 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
 	files_refname_path(refs, &ref_file, refname);
-	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
-					lock->old_oid.hash, type);
+	resolved = !!refs_resolve_ref_unsafe(&refs->base,
+					     refname, resolve_flags,
+					     lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
 		/*
 		 * we are trying to lock foo but we used to
@@ -2112,8 +2112,9 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 					    refname);
 			goto error_return;
 		}
-		resolved = !!resolve_ref_unsafe(refname, resolve_flags,
-						lock->old_oid.hash, type);
+		resolved = !!refs_resolve_ref_unsafe(&refs->base,
+						     refname, resolve_flags,
+						     lock->old_oid.hash, type);
 	}
 	if (!resolved) {
 		last_errno = errno;
@@ -2151,7 +2152,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 		goto error_return;
 	}
 
-	if (verify_lock(lock, old_sha1, mustexist, err)) {
+	if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
 		last_errno = errno;
 		goto error_return;
 	}
@@ -2406,7 +2407,7 @@ static void try_remove_empty_parents(struct files_ref_store *refs,
 }
 
 /* make sure nobody touched the ref, and unlink */
-static void prune_ref(struct ref_to_prune *r)
+static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -2414,7 +2415,7 @@ static void prune_ref(struct ref_to_prune *r)
 	if (check_refname_format(r->name, 0))
 		return;
 
-	transaction = ref_transaction_begin(&err);
+	transaction = ref_store_transaction_begin(&refs->base, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, r->name, r->sha1,
 				   REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
@@ -2428,10 +2429,10 @@ static void prune_ref(struct ref_to_prune *r)
 	strbuf_release(&err);
 }
 
-static void prune_refs(struct ref_to_prune *r)
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	while (r) {
-		prune_ref(r);
+		prune_ref(refs, r);
 		r = r->next;
 	}
 }
@@ -2455,7 +2456,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 	if (commit_packed_refs(refs))
 		die_errno("unable to overwrite old ref-pack file");
 
-	prune_refs(cbdata.ref_to_prune);
+	prune_refs(refs, cbdata.ref_to_prune);
 	return 0;
 }
 
@@ -2547,7 +2548,7 @@ static int files_delete_refs(struct ref_store *ref_store,
 	for (i = 0; i < refnames->nr; i++) {
 		const char *refname = refnames->items[i].string;
 
-		if (delete_ref(refname, NULL, flags))
+		if (refs_delete_ref(&refs->base, refname, NULL, flags))
 			result |= error(_("could not remove reference %s"), refname);
 	}
 
@@ -2665,8 +2666,9 @@ static int files_rename_ref(struct ref_store *ref_store,
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
-	if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				orig_sha1, &flag))
+	if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
+				     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+				     orig_sha1, &flag))
 		return error("refname %s not found", oldrefname);
 
 	if (flag & REF_ISSYMREF)
@@ -2684,7 +2686,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 		return error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
-	if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
+	if (refs_delete_ref(&refs->base, oldrefname, orig_sha1, REF_NODEREF)) {
 		error("unable to delete old %s", oldrefname);
 		goto rollback;
 	}
@@ -2696,9 +2698,10 @@ static int files_rename_ref(struct ref_store *ref_store,
 	 * the safety anyway; we want to delete the reference whatever
 	 * its current value.
 	 */
-	if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-			   sha1, NULL) &&
-	    delete_ref(newrefname, NULL, REF_NODEREF)) {
+	if (!refs_read_ref_full(&refs->base, newrefname,
+				RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+				sha1, NULL) &&
+	    refs_delete_ref(&refs->base, newrefname, NULL, REF_NODEREF)) {
 		if (errno == EISDIR) {
 			struct strbuf path = STRBUF_INIT;
 			int result;
@@ -3054,8 +3057,9 @@ static int commit_ref_update(struct files_ref_store *refs,
 		int head_flag;
 		const char *head_ref;
 
-		head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
-					      head_sha1, &head_flag);
+		head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
+						   RESOLVE_REF_READING,
+						   head_sha1, &head_flag);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
@@ -3099,7 +3103,9 @@ static void update_symref_reflog(struct files_ref_store *refs,
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
-	if (logmsg && !read_ref(target, new_sha1) &&
+	if (logmsg &&
+	    !refs_read_ref_full(&refs->base, target,
+				RESOLVE_REF_READING, new_sha1, NULL) &&
 	    files_log_ref_write(refs, refname, lock->old_oid.hash,
 				new_sha1, logmsg, 0, &err)) {
 		error("%s", err.buf);
@@ -3403,6 +3409,7 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store,
 struct files_reflog_iterator {
 	struct ref_iterator base;
 
+	struct ref_store *ref_store;
 	struct dir_iterator *dir_iterator;
 	struct object_id oid;
 };
@@ -3424,8 +3431,9 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 		if (ends_with(diter->basename, ".lock"))
 			continue;
 
-		if (read_ref_full(diter->relative_path, 0,
-				  iter->oid.hash, &flags)) {
+		if (refs_read_ref_full(iter->ref_store,
+				       diter->relative_path, 0,
+				       iter->oid.hash, &flags)) {
 			error("bad ref for %s", diter->path.buf);
 			continue;
 		}
@@ -3479,6 +3487,7 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
 	files_reflog_path(refs, &sb, NULL);
 	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	iter->ref_store = ref_store;
 	strbuf_release(&sb);
 	return ref_iterator;
 }
@@ -3718,8 +3727,9 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 			 * the transaction, so we have to read it here
 			 * to record and possibly check old_sha1:
 			 */
-			if (read_ref_full(referent.buf, 0,
-					  lock->old_oid.hash, NULL)) {
+			if (refs_read_ref_full(&refs->base,
+					       referent.buf, 0,
+					       lock->old_oid.hash, NULL)) {
 				if (update->flags & REF_HAVE_OLD) {
 					strbuf_addf(err, "cannot lock ref '%s': "
 						    "error reading reference",
@@ -3873,8 +3883,10 @@ static int files_transaction_commit(struct ref_store *ref_store,
 	 * head_ref within the transaction, then split_head_update()
 	 * arranges for the reflog of HEAD to be updated, too.
 	 */
-	head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,
-				  head_oid.hash, &head_type);
+	head_ref = (char *)refs_resolve_ref_unsafe(ref_store, "HEAD",
+						   RESOLVE_REF_NO_RECURSE,
+						   head_oid.hash, &head_type);
+	head_ref = xstrdup_or_null(head_ref);
 
 	if (head_ref && !(head_type & REF_ISSYMREF)) {
 		free(head_ref);
@@ -4047,7 +4059,8 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 	 * so here we really only check that none of the references
 	 * that we are creating already exists.
 	 */
-	if (for_each_rawref(ref_present, &affected_refnames))
+	if (refs_for_each_rawref(&refs->base, ref_present,
+				 &affected_refnames))
 		die("BUG: initial ref transaction called with existing refs");
 
 	for (i = 0; i < transaction->nr; i++) {
@@ -4166,7 +4179,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 		strbuf_release(&err);
 		return -1;
 	}
-	if (!reflog_exists(refname)) {
+	if (!refs_reflog_exists(ref_store, refname)) {
 		unlock_ref(lock);
 		return 0;
 	}
@@ -4197,7 +4210,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	}
 
 	(*prepare_fn)(refname, sha1, cb.policy_cb);
-	for_each_reflog_ent(refname, expire_reflog_ent, &cb);
+	refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
 	(*cleanup_fn)(cb.policy_cb);
 
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
-- 
2.11.0.157.gd943d85

Re: [PATCH v5 20/24] files-backend: avoid ref api targetting main ref store

[Michael Haggerty]

On 02/22/2017 03:04 PM, Nguyễn Thái Ngọc Duy wrote:
> A small step towards making files-backend works as a non-m