[PATCH 0/4] Handle FETCH_HEAD generically

[PATCH 0/4] Handle FETCH_HEAD generically

[Han-Wen Nienhuys via GitGitGadget]

This moves the FETCH_HEAD handling into refs.c as discussed in 
https://public-inbox.org/git/xmqq5z9pav01.fsf@gitster.c.googlers.com/

Han-Wen Nienhuys (4):
  Split off reading loose ref data in separate function
  refs: fix comment about submodule ref_stores
  refs: move gitdir into base ref_store
  refs: read FETCH_HEAD generically

 refs.c                | 27 +++++++++++++++++++++++-
 refs/files-backend.c  | 49 ++++++++++++++++++++++---------------------
 refs/packed-backend.c |  1 +
 refs/refs-internal.h  | 11 +++++++++-
 4 files changed, 62 insertions(+), 26 deletions(-)


base-commit: dc04167d378fb29d30e1647ff6ff51dd182bc9a3
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-705%2Fhanwen%2Ffetch-head-generically-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-705/hanwen/fetch-head-generically-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/705
-- 
gitgitgadget

[PATCH 1/4] Split off reading loose ref data in separate function

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

This prepares for handling FETCH_HEAD (which is not a regular ref)
separately from the ref backend.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 refs/files-backend.c | 34 +++++++++++++++++++---------------
 refs/refs-internal.h |  6 ++++++
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 985631f33e..3a3573986f 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -360,7 +360,6 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
 	const char *buf;
-	const char *p;
 	struct stat st;
 	int fd;
 	int ret = -1;
@@ -465,6 +464,21 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	close(fd);
 	strbuf_rtrim(&sb_contents);
 	buf = sb_contents.buf;
+
+	ret = parse_loose_ref_contents(buf, oid, referent, type);
+
+out:
+	save_errno = errno;
+	strbuf_release(&sb_path);
+	strbuf_release(&sb_contents);
+	errno = save_errno;
+	return ret;
+}
+
+int parse_loose_ref_contents(const char *buf, struct object_id *oid,
+			     struct strbuf *referent, unsigned int *type)
+{
+	const char *p;
 	if (skip_prefix(buf, "ref:", &buf)) {
 		while (isspace(*buf))
 			buf++;
@@ -472,29 +486,19 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 		strbuf_reset(referent);
 		strbuf_addstr(referent, buf);
 		*type |= REF_ISSYMREF;
-		ret = 0;
-		goto out;
+		return 0;
 	}
 
 	/*
-	 * Please note that FETCH_HEAD has additional
-	 * data after the sha.
+	 * FETCH_HEAD has additional data after the sha.
 	 */
 	if (parse_oid_hex(buf, oid, &p) ||
 	    (*p != '\0' && !isspace(*p))) {
 		*type |= REF_ISBROKEN;
 		errno = EINVAL;
-		goto out;
+		return -1;
 	}
-
-	ret = 0;
-
-out:
-	save_errno = errno;
-	strbuf_release(&sb_path);
-	strbuf_release(&sb_contents);
-	errno = save_errno;
-	return ret;
+	return 0;
 }
 
 static void unlock_ref(struct ref_lock *lock)
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 357359a0be..24d79fb5c1 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -674,6 +674,12 @@ struct ref_store {
 	const struct ref_storage_be *be;
 };
 
+/*
+ * Parse contents of a loose ref file.
+ */
+int parse_loose_ref_contents(const char *buf, struct object_id *oid,
+			     struct strbuf *referent, unsigned int *type);
+
 /*
  * Fill in the generic part of refs and add it to our collection of
  * reference stores.
-- 
gitgitgadget

[PATCH 2/4] refs: fix comment about submodule ref_stores

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

Signed-off-by: Han-Wen Nienhuys <hanwen@google.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 24d79fb5c1..9188ddbec2 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -667,7 +667,7 @@ extern struct ref_storage_be refs_be_packed;
 /*
  * A representation of the reference store for the main repository or
  * a submodule. The ref_store instances for submodules are kept in a
- * linked list.
+ * hash map; see get_submodule_ref_store() for more info.
  */
 struct ref_store {
 	/* The backend describing this ref_store's storage scheme: */
-- 
gitgitgadget

[PATCH 3/4] refs: move gitdir into base ref_store

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 refs/files-backend.c  | 15 ++++++---------
 refs/packed-backend.c |  1 +
 refs/refs-internal.h  |  3 +++
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 3a3573986f..dd712e47f4 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -67,7 +67,6 @@ struct files_ref_store {
 	struct ref_store base;
 	unsigned int store_flags;
 
-	char *gitdir;
 	char *gitcommondir;
 
 	struct ref_cache *loose;
@@ -94,18 +93,17 @@ static struct ref_store *files_ref_store_create(const char *gitdir,
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
 
+	ref_store->gitdir = xstrdup(gitdir);
 	base_ref_store_init(ref_store, &refs_be_files);
 	refs->store_flags = flags;
 
-	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_ref_store = packed_ref_store_create(sb.buf, flags);
 	strbuf_release(&sb);
 
-	chdir_notify_reparent("files-backend $GIT_DIR",
-			      &refs->gitdir);
+	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
 	chdir_notify_reparent("files-backend $GIT_COMMONDIR",
 			      &refs->gitcommondir);
 
@@ -176,7 +174,7 @@ static void files_reflog_path(struct files_ref_store *refs,
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
-		strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
+		strbuf_addf(sb, "%s/logs/%s", refs->base.gitdir, refname);
 		break;
 	case REF_TYPE_OTHER_PSEUDOREF:
 	case REF_TYPE_MAIN_PSEUDOREF:
@@ -198,7 +196,7 @@ static void files_ref_path(struct files_ref_store *refs,
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
-		strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
+		strbuf_addf(sb, "%s/%s", refs->base.gitdir, refname);
 		break;
 	case REF_TYPE_MAIN_PSEUDOREF:
 		if (!skip_prefix(refname, "main-worktree/", &refname))
@@ -2203,12 +2201,11 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 		files_downcast(ref_store, REF_STORE_READ,
 			       "reflog_iterator_begin");
 
-	if (!strcmp(refs->gitdir, refs->gitcommondir)) {
+	if (!strcmp(refs->base.gitdir, refs->gitcommondir)) {
 		return reflog_iterator_begin(ref_store, refs->gitcommondir);
 	} else {
 		return merge_ref_iterator_begin(
-			0,
-			reflog_iterator_begin(ref_store, refs->gitdir),
+			0, reflog_iterator_begin(ref_store, refs->base.gitdir),
 			reflog_iterator_begin(ref_store, refs->gitcommondir),
 			reflog_iterator_select, refs);
 	}
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4458a0f69c..b912f2505f 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -200,6 +200,7 @@ struct ref_store *packed_ref_store_create(const char *path,
 	struct ref_store *ref_store = (struct ref_store *)refs;
 
 	base_ref_store_init(ref_store, &refs_be_packed);
+	ref_store->gitdir = xstrdup(path);
 	refs->store_flags = store_flags;
 
 	refs->path = xstrdup(path);
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 9188ddbec2..527b0a6e2e 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -672,6 +672,9 @@ extern struct ref_storage_be refs_be_packed;
 struct ref_store {
 	/* The backend describing this ref_store's storage scheme: */
 	const struct ref_storage_be *be;
+
+	/* The gitdir that this ref_store applies to: */
+	char *gitdir;
 };
 
 /*
-- 
gitgitgadget

[PATCH 4/4] refs: read FETCH_HEAD generically

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

The FETCH_HEAD ref must be stored in a file, regardless of the type of
ref backend. This is because it can hold more than just a single ref.

To accomodate FETCH_HEAD for alternate ref backends, read FETCH_HEAD
from a file generically in refs_read_raw_ref()

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 refs.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 2dd851fe81..ab7d62e237 100644
--- a/refs.c
+++ b/refs.c
@@ -1634,11 +1634,36 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
 	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
+static int refs_read_fetch_head(struct ref_store *ref_store,
+				struct object_id *oid, struct strbuf *referent,
+				unsigned int *type)
+{
+	struct strbuf full_path = STRBUF_INIT;
+	struct strbuf content = STRBUF_INIT;
+	int result = -1;
+	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, "FETCH_HEAD");
+
+	if (strbuf_read_file(&content, full_path.buf, 0) < 0)
+		goto done;
+
+	result = parse_loose_ref_contents(content.buf, oid, referent, type);
+
+done:
+	strbuf_release(&full_path);
+	strbuf_release(&content);
+	return result;
+}
+
 int refs_read_raw_ref(struct ref_store *ref_store,
 		      const char *refname, struct object_id *oid,
 		      struct strbuf *referent, unsigned int *type)
 {
-	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
+	if (!strcmp(refname, "FETCH_HEAD")) {
+		return refs_read_fetch_head(ref_store, oid, referent, type);
+	}
+
+	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
+					   type);
 }
 
 /* This function needs to return a meaningful errno on failure */
-- 
gitgitgadget

Re: [PATCH 0/4] Handle FETCH_HEAD generically

[Junio C Hamano]

"Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:

> This moves the FETCH_HEAD handling into refs.c as discussed in 
> https://public-inbox.org/git/xmqq5z9pav01.fsf@gitster.c.googlers.com/
>
> Han-Wen Nienhuys (4):
>   Split off reading loose ref data in separate function
>   refs: fix comment about submodule ref_stores
>   refs: move gitdir into base ref_store
>   refs: read FETCH_HEAD generically
>
>  refs.c                | 27 +++++++++++++++++++++++-
>  refs/files-backend.c  | 49 ++++++++++++++++++++++---------------------
>  refs/packed-backend.c |  1 +
>  refs/refs-internal.h  | 11 +++++++++-
>  4 files changed, 62 insertions(+), 26 deletions(-)

Nice.  Quite cleanly done.

Will queue; thanks.

[PATCH v2 0/4] Handle FETCH_HEAD and MERGE_HEAD generically

[Han-Wen Nienhuys via GitGitGadget]

This moves the FETCH_HEAD handling into refs.c as discussed in 
https://public-inbox.org/git/xmqq5z9pav01.fsf@gitster.c.googlers.com/

Han-Wen Nienhuys (4):
  refs: split off reading loose ref data in separate function
  refs: fix comment about submodule ref_stores
  refs: move gitdir into base ref_store
  refs: read FETCH_HEAD and MERGE_HEAD generically

 refs.c                | 28 ++++++++++++++++++++++++-
 refs/files-backend.c  | 49 ++++++++++++++++++++++---------------------
 refs/packed-backend.c |  1 +
 refs/refs-internal.h  | 11 +++++++++-
 4 files changed, 63 insertions(+), 26 deletions(-)


base-commit: 2befe97201e1f3175cce557866c5822793624b5a
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-705%2Fhanwen%2Ffetch-head-generically-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-705/hanwen/fetch-head-generically-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/705

Range-diff vs v1:

 1:  10b333695e ! 1:  557727064d Split off reading loose ref data in separate function
     @@ Metadata
      Author: Han-Wen Nienhuys <hanwen@google.com>
      
       ## Commit message ##
     -    Split off reading loose ref data in separate function
     +    refs: split off reading loose ref data in separate function
      
          This prepares for handling FETCH_HEAD (which is not a regular ref)
          separately from the ref backend.
 2:  52b397ec9e = 2:  6da0e62e73 refs: fix comment about submodule ref_stores
 3:  c624e17dc6 = 3:  6263b4b3f2 refs: move gitdir into base ref_store
 4:  d4e9c5f499 ! 4:  a3e903e4c0 refs: read FETCH_HEAD generically
     @@ Metadata
      Author: Han-Wen Nienhuys <hanwen@google.com>
      
       ## Commit message ##
     -    refs: read FETCH_HEAD generically
     +    refs: read FETCH_HEAD and MERGE_HEAD generically
      
     -    The FETCH_HEAD ref must be stored in a file, regardless of the type of
     -    ref backend. This is because it can hold more than just a single ref.
     +    The FETCH_HEAD and MERGE_HEAD refs must be stored in a file, regardless of the
     +    type of ref backend. This is because they can hold more than just a single ref.
      
     -    To accomodate FETCH_HEAD for alternate ref backends, read FETCH_HEAD
     -    from a file generically in refs_read_raw_ref()
     +    To accomodate them for alternate ref backends, read them from a file generically
     +    in refs_read_raw_ref()
      
          Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
      
     @@ refs.c: int for_each_rawref(each_ref_fn fn, void *cb_data)
       	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
       }
       
     -+static int refs_read_fetch_head(struct ref_store *ref_store,
     -+				struct object_id *oid, struct strbuf *referent,
     -+				unsigned int *type)
     ++static int refs_read_special_head(struct ref_store *ref_store,
     ++				  const char *refname, struct object_id *oid,
     ++				  struct strbuf *referent, unsigned int *type)
      +{
      +	struct strbuf full_path = STRBUF_INIT;
      +	struct strbuf content = STRBUF_INIT;
      +	int result = -1;
     -+	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, "FETCH_HEAD");
     ++	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
      +
      +	if (strbuf_read_file(&content, full_path.buf, 0) < 0)
      +		goto done;
     @@ refs.c: int for_each_rawref(each_ref_fn fn, void *cb_data)
       		      struct strbuf *referent, unsigned int *type)
       {
      -	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
     -+	if (!strcmp(refname, "FETCH_HEAD")) {
     -+		return refs_read_fetch_head(ref_store, oid, referent, type);
     ++	if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
     ++		return refs_read_special_head(ref_store, refname, oid, referent,
     ++					      type);
      +	}
      +
      +	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,

-- 
gitgitgadget

[PATCH v2 1/4] refs: split off reading loose ref data in separate function

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

This prepares for handling FETCH_HEAD (which is not a regular ref)
separately from the ref backend.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 refs/files-backend.c | 34 +++++++++++++++++++---------------
 refs/refs-internal.h |  6 ++++++
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 985631f33e..3a3573986f 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -360,7 +360,6 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
 	const char *buf;
-	const char *p;
 	struct stat st;
 	int fd;
 	int ret = -1;
@@ -465,6 +464,21 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 	close(fd);
 	strbuf_rtrim(&sb_contents);
 	buf = sb_contents.buf;
+
+	ret = parse_loose_ref_contents(buf, oid, referent, type);
+
+out:
+	save_errno = errno;
+	strbuf_release(&sb_path);
+	strbuf_release(&sb_contents);
+	errno = save_errno;
+	return ret;
+}
+
+int parse_loose_ref_contents(const char *buf, struct object_id *oid,
+			     struct strbuf *referent, unsigned int *type)
+{
+	const char *p;
 	if (skip_prefix(buf, "ref:", &buf)) {
 		while (isspace(*buf))
 			buf++;
@@ -472,29 +486,19 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 		strbuf_reset(referent);
 		strbuf_addstr(referent, buf);
 		*type |= REF_ISSYMREF;
-		ret = 0;
-		goto out;
+		return 0;
 	}
 
 	/*
-	 * Please note that FETCH_HEAD has additional
-	 * data after the sha.
+	 * FETCH_HEAD has additional data after the sha.
 	 */
 	if (parse_oid_hex(buf, oid, &p) ||
 	    (*p != '\0' && !isspace(*p))) {
 		*type |= REF_ISBROKEN;
 		errno = EINVAL;
-		goto out;
+		return -1;
 	}
-
-	ret = 0;
-
-out:
-	save_errno = errno;
-	strbuf_release(&sb_path);
-	strbuf_release(&sb_contents);
-	errno = save_errno;
-	return ret;
+	return 0;
 }
 
 static void unlock_ref(struct ref_lock *lock)
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 357359a0be..24d79fb5c1 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -674,6 +674,12 @@ struct ref_store {
 	const struct ref_storage_be *be;
 };
 
+/*
+ * Parse contents of a loose ref file.
+ */
+int parse_loose_ref_contents(const char *buf, struct object_id *oid,
+			     struct strbuf *referent, unsigned int *type);
+
 /*
  * Fill in the generic part of refs and add it to our collection of
  * reference stores.
-- 
gitgitgadget

[PATCH v2 2/4] refs: fix comment about submodule ref_stores

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

Signed-off-by: Han-Wen Nienhuys <hanwen@google.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 24d79fb5c1..9188ddbec2 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -667,7 +667,7 @@ extern struct ref_storage_be refs_be_packed;
 /*
  * A representation of the reference store for the main repository or
  * a submodule. The ref_store instances for submodules are kept in a
- * linked list.
+ * hash map; see get_submodule_ref_store() for more info.
  */
 struct ref_store {
 	/* The backend describing this ref_store's storage scheme: */
-- 
gitgitgadget

[PATCH v2 3/4] refs: move gitdir into base ref_store

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 refs/files-backend.c  | 15 ++++++---------
 refs/packed-backend.c |  1 +
 refs/refs-internal.h  |  3 +++
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 3a3573986f..dd712e47f4 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -67,7 +67,6 @@ struct files_ref_store {
 	struct ref_store base;
 	unsigned int store_flags;
 
-	char *gitdir;
 	char *gitcommondir;
 
 	struct ref_cache *loose;
@@ -94,18 +93,17 @@ static struct ref_store *files_ref_store_create(const char *gitdir,
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
 
+	ref_store->gitdir = xstrdup(gitdir);
 	base_ref_store_init(ref_store, &refs_be_files);
 	refs->store_flags = flags;
 
-	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_ref_store = packed_ref_store_create(sb.buf, flags);
 	strbuf_release(&sb);
 
-	chdir_notify_reparent("files-backend $GIT_DIR",
-			      &refs->gitdir);
+	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
 	chdir_notify_reparent("files-backend $GIT_COMMONDIR",
 			      &refs->gitcommondir);
 
@@ -176,7 +174,7 @@ static void files_reflog_path(struct files_ref_store *refs,
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
-		strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
+		strbuf_addf(sb, "%s/logs/%s", refs->base.gitdir, refname);
 		break;
 	case REF_TYPE_OTHER_PSEUDOREF:
 	case REF_TYPE_MAIN_PSEUDOREF:
@@ -198,7 +196,7 @@ static void files_ref_path(struct files_ref_store *refs,
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
-		strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
+		strbuf_addf(sb, "%s/%s", refs->base.gitdir, refname);
 		break;
 	case REF_TYPE_MAIN_PSEUDOREF:
 		if (!skip_prefix(refname, "main-worktree/", &refname))
@@ -2203,12 +2201,11 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
 		files_downcast(ref_store, REF_STORE_READ,
 			       "reflog_iterator_begin");
 
-	if (!strcmp(refs->gitdir, refs->gitcommondir)) {
+	if (!strcmp(refs->base.gitdir, refs->gitcommondir)) {
 		return reflog_iterator_begin(ref_store, refs->gitcommondir);
 	} else {
 		return merge_ref_iterator_begin(
-			0,
-			reflog_iterator_begin(ref_store, refs->gitdir),
+			0, reflog_iterator_begin(ref_store, refs->base.gitdir),
 			reflog_iterator_begin(ref_store, refs->gitcommondir),
 			reflog_iterator_select, refs);
 	}
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4458a0f69c..b912f2505f 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -200,6 +200,7 @@ struct ref_store *packed_ref_store_create(const char *path,
 	struct ref_store *ref_store = (struct ref_store *)refs;
 
 	base_ref_store_init(ref_store, &refs_be_packed);
+	ref_store->gitdir = xstrdup(path);
 	refs->store_flags = store_flags;
 
 	refs->path = xstrdup(path);
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 9188ddbec2..527b0a6e2e 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -672,6 +672,9 @@ extern struct ref_storage_be refs_be_packed;
 struct ref_store {
 	/* The backend describing this ref_store's storage scheme: */
 	const struct ref_storage_be *be;
+
+	/* The gitdir that this ref_store applies to: */
+	char *gitdir;
 };
 
 /*
-- 
gitgitgadget

[PATCH v2 4/4] refs: read FETCH_HEAD and MERGE_HEAD generically

[Han-Wen Nienhuys via GitGitGadget]

From: Han-Wen Nienhuys <hanwen@google.com>

The FETCH_HEAD and MERGE_HEAD refs must be stored in a file, regardless of the
type of ref backend. This is because they can hold more than just a single ref.

To accomodate them for alternate ref backends, read them from a file generically
in refs_read_raw_ref()

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 refs.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index cf91711968..3ee3afaf41 100644
--- a/refs.c
+++ b/refs.c
@@ -1527,11 +1527,37 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
 	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
+static int refs_read_special_head(struct ref_store *ref_store,
+				  const char *refname, struct object_id *oid,
+				  struct strbuf *referent, unsigned int *type)
+{
+	struct strbuf full_path = STRBUF_INIT;
+	struct strbuf content = STRBUF_INIT;
+	int result = -1;
+	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
+
+	if (strbuf_read_file(&content, full_path.buf, 0) < 0)
+		goto done;
+
+	result = parse_loose_ref_contents(content.buf, oid, referent, type);
+
+done:
+	strbuf_release(&full_path);
+	strbuf_release(&content);
+	return result;
+}
+
 int refs_read_raw_ref(struct ref_store *ref_store,
 		      const char *refname, struct object_id *oid,
 		      struct strbuf *referent, unsigned int *type)
 {
-	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
+	if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
+		return refs_read_special_head(ref_store, refname, oid, referent,
+					      type);
+	}
+
+	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
+					   type);
 }
 
 /* This function needs to return a meaningful errno on failure */
-- 
gitgitgadget

Re: [PATCH v2 0/4] Handle FETCH_HEAD and MERGE_HEAD generically

[Junio C Hamano]

"Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:

> This moves the FETCH_HEAD handling into refs.c as discussed in 
> https://public-inbox.org/git/xmqq5z9pav01.fsf@gitster.c.googlers.com/

Thanks.  The way the support for MERGE_HEAD is added to the series
looks very sensible, too.

Will replace.

>      -+static int refs_read_fetch_head(struct ref_store *ref_store,
>      -+				struct object_id *oid, struct strbuf *referent,
>      -+				unsigned int *type)
>      ++static int refs_read_special_head(struct ref_store *ref_store,
>      ++				  const char *refname, struct object_id *oid,
>      ++				  struct strbuf *referent, unsigned int *type)
>       +{
>       +	struct strbuf full_path = STRBUF_INIT;
>       +	struct strbuf content = STRBUF_INIT;
>       +	int result = -1;
>      -+	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, "FETCH_HEAD");
>      ++	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
>       +
>       +	if (strbuf_read_file(&content, full_path.buf, 0) < 0)
>       +		goto done;
>      @@ refs.c: int for_each_rawref(each_ref_fn fn, void *cb_data)
>        		      struct strbuf *referent, unsigned int *type)
>        {
>       -	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
>      -+	if (!strcmp(refname, "FETCH_HEAD")) {
>      -+		return refs_read_fetch_head(ref_store, oid, referent, type);
>      ++	if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
>      ++		return refs_read_special_head(ref_store, refname, oid, referent,
>      ++					      type);
>       +	}
>       +
>       +	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,