[PATCH v2 00/42] object_id part 13

[PATCH v2 00/42] object_id part 13

[brian m. carlson]

This is the thirteenth series of patches to convert to struct object_id
and the_hash_algo.

The series adds an oidread function to read object IDs from a buffer,
removes unused structure members (which therefore don't require
conversion), converts various functions to struct object_id, and
improves usage of the_hash_algo.  It also makes empty_blob_oid and
empty_tree_oid static, exposed only through the hash algorithm
abstraction, and updates all the hard-coded instances of the empty blob
and empty tree object IDs in scripts (excepting the testsuite).

Changes from v1:
* Add missing sign-off.
* Removed unneeded braces from init_pack_info.
* Express 51 in terms of the_hash_algo->hexsz.
* Fix comments referring to SHA-1.
* Update commit messages as suggested.
* Add and use empty_tree_oid_hex and empty_blob_oid_hex.

brian m. carlson (42):
  cache: add a function to read an object ID from a buffer
  server-info: remove unused members from struct pack_info
  Remove unused member in struct object_context
  packfile: remove unused member from struct pack_entry
  packfile: convert has_sha1_pack to object_id
  sha1-file: convert freshen functions to object_id
  packfile: convert find_pack_entry to object_id
  packfile: abstract away hash constant values
  pack-objects: abstract away hash algorithm
  pack-redundant: abstract away hash algorithm
  tree-walk: avoid hard-coded 20 constant
  tree-walk: convert get_tree_entry_follow_symlinks to object_id
  fsck: convert static functions to struct object_id
  submodule-config: convert structures to object_id
  split-index: convert struct split_index to object_id
  Update struct index_state to use struct object_id
  pack-redundant: convert linked lists to use struct object_id
  index-pack: abstract away hash function constant
  commit: convert uses of get_sha1_hex to get_oid_hex
  dir: convert struct untracked_cache_dir to object_id
  http: eliminate hard-coded constants
  revision: replace use of hard-coded constants
  upload-pack: replace use of several hard-coded constants
  diff: specify abbreviation size in terms of the_hash_algo
  builtin/receive-pack: avoid hard-coded constants for push certs
  sha1-file: add functions for hex empty tree and blob OIDs
  builtin/am: convert uses of EMPTY_TREE_SHA1_BIN to the_hash_algo
  builtin/merge: switch tree functions to use object_id
  merge: convert empty tree constant to the_hash_algo
  sequencer: convert one use of EMPTY_TREE_SHA1_HEX
  submodule: convert several uses of EMPTY_TREE_SHA1_HEX
  wt-status: convert two uses of EMPTY_TREE_SHA1_HEX
  builtin/receive-pack: convert one use of EMPTY_TREE_SHA1_HEX
  builtin/reset: convert use of EMPTY_TREE_SHA1_BIN
  sha1_file: convert cached object code to struct object_id
  cache-tree: use is_empty_tree_oid
  sequencer: use the_hash_algo for empty tree object ID
  dir: use the_hash_algo for empty blob object ID
  sha1_file: only expose empty object constants through git_hash_algo
  Update shell scripts to compute empty tree object ID
  add--interactive: compute the empty tree value
  merge-one-file: compute empty blob object ID

 builtin/am.c                         |  8 +--
 builtin/count-objects.c              |  2 +-
 builtin/fsck.c                       |  2 +-
 builtin/index-pack.c                 |  3 +-
 builtin/merge.c                      | 14 ++---
 builtin/pack-objects.c               | 32 +++++------
 builtin/pack-redundant.c             | 62 +++++++++++----------
 builtin/prune-packed.c               |  2 +-
 builtin/receive-pack.c               |  8 +--
 builtin/reset.c                      |  2 +-
 builtin/rev-parse.c                  |  4 +-
 cache-tree.c                         |  4 +-
 cache.h                              | 28 ++++------
 commit.c                             |  4 +-
 diff.c                               | 20 ++++---
 dir.c                                | 25 ++++-----
 dir.h                                |  5 +-
 fsck.c                               | 20 +++----
 git-add--interactive.perl            | 11 +++-
 git-filter-branch.sh                 |  4 +-
 git-merge-one-file.sh                |  2 +-
 git-rebase--interactive.sh           |  4 +-
 http.c                               | 13 ++---
 merge.c                              |  5 +-
 packfile.c                           | 79 ++++++++++++++-------------
 packfile.h                           |  4 +-
 read-cache.c                         | 34 ++++++------
 resolve-undo.c                       |  2 +-
 revision.c                           |  7 +--
 sequencer.c                          |  4 +-
 server-info.c                        |  9 +---
 sha1-file.c                          | 81 +++++++++++++++++-----------
 sha1-name.c                          |  5 +-
 split-index.c                        | 10 ++--
 split-index.h                        |  4 +-
 submodule-config.c                   | 66 +++++++++++------------
 submodule-config.h                   |  7 +--
 submodule.c                          |  6 +--
 t/helper/test-dump-split-index.c     |  4 +-
 t/helper/test-dump-untracked-cache.c |  2 +-
 templates/hooks--pre-commit.sample   |  2 +-
 tree-walk.c                          | 18 +++----
 tree-walk.h                          |  2 +-
 unpack-trees.c                       |  2 +-
 upload-pack.c                        | 18 +++----
 wt-status.c                          |  4 +-
 46 files changed, 348 insertions(+), 306 deletions(-)

[PATCH v2 01/42] cache: add a function to read an object ID from a buffer

[brian m. carlson]

In various places throughout the codebase, we need to read data into a
struct object_id from a pack or other unsigned char buffer.  Add an
inline function that does this based on the current hash algorithm in
use, and use it in several places.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache-tree.c   | 2 +-
 cache.h        | 5 +++++
 resolve-undo.c | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/cache-tree.c b/cache-tree.c
index 6a555f4d43..8c7e1258a4 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -523,7 +523,7 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 	if (0 <= it->entry_count) {
 		if (size < rawsz)
 			goto free_return;
-		memcpy(it->oid.hash, (const unsigned char*)buf, rawsz);
+		oidread(&it->oid, (const unsigned char *)buf);
 		buf += rawsz;
 		size -= rawsz;
 	}
diff --git a/cache.h b/cache.h
index 77b7acebb6..af6693f352 100644
--- a/cache.h
+++ b/cache.h
@@ -1008,6 +1008,11 @@ static inline void oidclr(struct object_id *oid)
 	memset(oid->hash, 0, GIT_MAX_RAWSZ);
 }
 
+static inline void oidread(struct object_id *oid, const unsigned char *hash)
+{
+	memcpy(oid->hash, hash, the_hash_algo->rawsz);
+}
+
 
 #define EMPTY_TREE_SHA1_HEX \
 	"4b825dc642cb6eb9a060e54bf8d69288fbee4904"
diff --git a/resolve-undo.c b/resolve-undo.c
index aed95b4b35..fc5b3b83d9 100644
--- a/resolve-undo.c
+++ b/resolve-undo.c
@@ -90,7 +90,7 @@ struct string_list *resolve_undo_read(const char *data, unsigned long size)
 				continue;
 			if (size < rawsz)
 				goto error;
-			memcpy(ui->oid[i].hash, (const unsigned char *)data, rawsz);
+			oidread(&ui->oid[i], (const unsigned char *)data);
 			size -= rawsz;
 			data += rawsz;
 		}

[PATCH v2 02/42] server-info: remove unused members from struct pack_info

[brian m. carlson]

The head member of struct pack_info is completely unused and the
nr_heads member is used only in one place, which is an assignment.  This
member was last usefully used in 3e15c67c90 (server-info: throw away T
computation as well, 2005-12-04).

Since this structure member is not useful, remove it.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 server-info.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/server-info.c b/server-info.c
index 83460ec0d6..7ce6dcd67b 100644
--- a/server-info.c
+++ b/server-info.c
@@ -92,8 +92,6 @@ static struct pack_info {
 	int old_num;
 	int new_num;
 	int nr_alloc;
-	int nr_heads;
-	unsigned char (*head)[20];
 } **info;
 static int num_pack;
 static const char *objdir;
@@ -225,12 +223,9 @@ static void init_pack_info(const char *infofile, int force)
 	else
 		stale = 1;
 
-	for (i = 0; i < num_pack; i++) {
-		if (stale) {
+	for (i = 0; i < num_pack; i++)
+		if (stale)
 			info[i]->old_num = -1;
-			info[i]->nr_heads = 0;
-		}
-	}
 
 	/* renumber them */
 	QSORT(info, num_pack, compare_info);

[PATCH v2 03/42] Remove unused member in struct object_context

[brian m. carlson]

The tree member of struct object_context is unused except in one place
where we write to it.  Since there are no users of this member, remove
it.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h     | 1 -
 sha1-name.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/cache.h b/cache.h
index af6693f352..be9fab43ec 100644
--- a/cache.h
+++ b/cache.h
@@ -1306,7 +1306,6 @@ static inline int hex2chr(const char *s)
 #define FALLBACK_DEFAULT_ABBREV 7
 
 struct object_context {
-	unsigned char tree[20];
 	unsigned mode;
 	/*
 	 * symlink_path is only used by get_tree_entry_follow_symlinks,
diff --git a/sha1-name.c b/sha1-name.c
index 5b93bf8da3..7043652a24 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -1698,7 +1698,6 @@ static int get_oid_with_context_1(const char *name,
 								   name, len);
 				}
 			}
-			hashcpy(oc->tree, tree_oid.hash);
 			if (flags & GET_OID_RECORD_PATH)
 				oc->path = xstrdup(filename);
 

[PATCH v2 04/42] packfile: remove unused member from struct pack_entry

[brian m. carlson]

The sha1 member in struct pack_entry is unused except for one instance
in which we store a value in it.  Since nobody ever reads this value,
don't bother to compute it and remove the member from struct pack_entry.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h    | 1 -
 packfile.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/cache.h b/cache.h
index be9fab43ec..37d3f0104b 100644
--- a/cache.h
+++ b/cache.h
@@ -1572,7 +1572,6 @@ struct pack_window {
 
 struct pack_entry {
 	off_t offset;
-	unsigned char sha1[20];
 	struct packed_git *p;
 };
 
diff --git a/packfile.c b/packfile.c
index 0bc67d0e00..5c219d0229 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1833,7 +1833,6 @@ static int fill_pack_entry(const unsigned char *sha1,
 		return 0;
 	e->offset = offset;
 	e->p = p;
-	hashcpy(e->sha1, sha1);
 	return 1;
 }
 

[PATCH v2 05/42] packfile: convert has_sha1_pack to object_id

[brian m. carlson]

Convert this function to take a pointer to struct object_id and rename
it has_object_pack for consistency with has_object_file.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/count-objects.c | 2 +-
 builtin/fsck.c          | 2 +-
 builtin/prune-packed.c  | 2 +-
 diff.c                  | 2 +-
 packfile.c              | 4 ++--
 packfile.h              | 2 +-
 revision.c              | 2 +-
 7 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/builtin/count-objects.c b/builtin/count-objects.c
index b054713e1a..d51e2ce1ec 100644
--- a/builtin/count-objects.c
+++ b/builtin/count-objects.c
@@ -66,7 +66,7 @@ static int count_loose(const struct object_id *oid, const char *path, void *data
 	else {
 		loose_size += on_disk_bytes(st);
 		loose++;
-		if (verbose && has_sha1_pack(oid->hash))
+		if (verbose && has_object_pack(oid))
 			packed_loose++;
 	}
 	return 0;
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 087360a675..3eb82ac44f 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -227,7 +227,7 @@ static void check_reachable_object(struct object *obj)
 	if (!(obj->flags & HAS_OBJ)) {
 		if (is_promisor_object(&obj->oid))
 			return;
-		if (has_sha1_pack(obj->oid.hash))
+		if (has_object_pack(&obj->oid))
 			return; /* it is in pack - forget about it */
 		printf("missing %s %s\n", printable_type(obj),
 			describe_object(obj));
diff --git a/builtin/prune-packed.c b/builtin/prune-packed.c
index 419238171d..4ff525e50f 100644
--- a/builtin/prune-packed.c
+++ b/builtin/prune-packed.c
@@ -25,7 +25,7 @@ static int prune_object(const struct object_id *oid, const char *path,
 {
 	int *opts = data;
 
-	if (!has_sha1_pack(oid->hash))
+	if (!has_object_pack(oid))
 		return 0;
 
 	if (*opts & PRUNE_PACKED_DRY_RUN)
diff --git a/diff.c b/diff.c
index 1289df4b1f..314c57e3c0 100644
--- a/diff.c
+++ b/diff.c
@@ -3472,7 +3472,7 @@ static int reuse_worktree_file(const char *name, const struct object_id *oid, in
 	 * objects however would tend to be slower as they need
 	 * to be individually opened and inflated.
 	 */
-	if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
+	if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
 		return 0;
 
 	/*
diff --git a/packfile.c b/packfile.c
index 5c219d0229..e65f943664 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1854,10 +1854,10 @@ int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack
 	return 0;
 }
 
-int has_sha1_pack(const unsigned char *sha1)
+int has_object_pack(const struct object_id *oid)
 {
 	struct pack_entry e;
-	return find_pack_entry(the_repository, sha1, &e);
+	return find_pack_entry(the_repository, oid->hash, &e);
 }
 
 int has_pack_index(const unsigned char *sha1)
diff --git a/packfile.h b/packfile.h
index a92c0b241c..14ca34bcbd 100644
--- a/packfile.h
+++ b/packfile.h
@@ -136,7 +136,7 @@ extern const struct packed_git *has_packed_and_bad(const unsigned char *sha1);
  */
 extern int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack_entry *e);
 
-extern int has_sha1_pack(const unsigned char *sha1);
+extern int has_object_pack(const struct object_id *oid);
 
 extern int has_pack_index(const unsigned char *sha1);
 
diff --git a/revision.c b/revision.c
index b42c836d7a..ce0e7b71f2 100644
--- a/revision.c
+++ b/revision.c
@@ -3086,7 +3086,7 @@ enum commit_action get_commit_action(struct rev_info *revs, struct commit *commi
 {
 	if (commit->object.flags & SHOWN)
 		return commit_ignore;
-	if (revs->unpacked && has_sha1_pack(commit->object.oid.hash))
+	if (revs->unpacked && has_object_pack(&commit->object.oid))
 		return commit_ignore;
 	if (commit->object.flags & UNINTERESTING)
 		return commit_ignore;

[PATCH v2 06/42] sha1-file: convert freshen functions to object_id

[brian m. carlson]

Convert the various functions for freshening objects and
has_loose_object_nonlocal to use struct object_id.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/pack-objects.c |  2 +-
 cache.h                |  2 +-
 sha1-file.c            | 36 ++++++++++++++++++------------------
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 4bdae5a1d8..907e112331 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1012,7 +1012,7 @@ static int want_object_in_pack(const struct object_id *oid,
 	int want;
 	struct list_head *pos;
 
-	if (!exclude && local && has_loose_object_nonlocal(oid->hash))
+	if (!exclude && local && has_loose_object_nonlocal(oid))
 		return 0;
 
 	/*
diff --git a/cache.h b/cache.h
index 37d3f0104b..f06737fb78 100644
--- a/cache.h
+++ b/cache.h
@@ -1275,7 +1275,7 @@ extern int has_object_file_with_flags(const struct object_id *oid, int flags);
  * with the specified name.  This function does not respect replace
  * references.
  */
-extern int has_loose_object_nonlocal(const unsigned char *sha1);
+extern int has_loose_object_nonlocal(const struct object_id *oid);
 
 extern void assert_oid_type(const struct object_id *oid, enum object_type expect);
 
diff --git a/sha1-file.c b/sha1-file.c
index 77ccaab928..1617e25495 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -709,42 +709,42 @@ int check_and_freshen_file(const char *fn, int freshen)
 	return 1;
 }
 
-static int check_and_freshen_local(const unsigned char *sha1, int freshen)
+static int check_and_freshen_local(const struct object_id *oid, int freshen)
 {
 	static struct strbuf buf = STRBUF_INIT;
 
 	strbuf_reset(&buf);
-	sha1_file_name(the_repository, &buf, sha1);
+	sha1_file_name(the_repository, &buf, oid->hash);
 
 	return check_and_freshen_file(buf.buf, freshen);
 }
 
-static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
+static int check_and_freshen_nonlocal(const struct object_id *oid, int freshen)
 {
 	struct alternate_object_database *alt;
 	prepare_alt_odb(the_repository);
 	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
-		const char *path = alt_sha1_path(alt, sha1);
+		const char *path = alt_sha1_path(alt, oid->hash);
 		if (check_and_freshen_file(path, freshen))
 			return 1;
 	}
 	return 0;
 }
 
-static int check_and_freshen(const unsigned char *sha1, int freshen)
+static int check_and_freshen(const struct object_id *oid, int freshen)
 {
-	return check_and_freshen_local(sha1, freshen) ||
-	       check_and_freshen_nonlocal(sha1, freshen);
+	return check_and_freshen_local(oid, freshen) ||
+	       check_and_freshen_nonlocal(oid, freshen);
 }
 
-int has_loose_object_nonlocal(const unsigned char *sha1)
+int has_loose_object_nonlocal(const struct object_id *oid)
 {
-	return check_and_freshen_nonlocal(sha1, 0);
+	return check_and_freshen_nonlocal(oid, 0);
 }
 
-static int has_loose_object(const unsigned char *sha1)
+static int has_loose_object(const struct object_id *oid)
 {
-	return check_and_freshen(sha1, 0);
+	return check_and_freshen(oid, 0);
 }
 
 static void mmap_limit_check(size_t length)
@@ -1661,15 +1661,15 @@ static int write_loose_object(const struct object_id *oid, char *hdr,
 	return finalize_object_file(tmp_file.buf, filename.buf);
 }
 
-static int freshen_loose_object(const unsigned char *sha1)
+static int freshen_loose_object(const struct object_id *oid)
 {
-	return check_and_freshen(sha1, 1);
+	return check_and_freshen(oid, 1);
 }
 
-static int freshen_packed_object(const unsigned char *sha1)
+static int freshen_packed_object(const struct object_id *oid)
 {
 	struct pack_entry e;
-	if (!find_pack_entry(the_repository, sha1, &e))
+	if (!find_pack_entry(the_repository, oid->hash, &e))
 		return 0;
 	if (e.p->freshened)
 		return 1;
@@ -1689,7 +1689,7 @@ int write_object_file(const void *buf, unsigned long len, const char *type,
 	 * it out into .git/objects/??/?{38} file.
 	 */
 	write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
-	if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
+	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		return 0;
 	return write_loose_object(oid, hdr, hdrlen, buf, len, 0);
 }
@@ -1708,7 +1708,7 @@ int hash_object_file_literally(const void *buf, unsigned long len,
 
 	if (!(flags & HASH_WRITE_OBJECT))
 		goto cleanup;
-	if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
+	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		goto cleanup;
 	status = write_loose_object(oid, header, hdrlen, buf, len, 0);
 
@@ -1726,7 +1726,7 @@ int force_object_loose(const struct object_id *oid, time_t mtime)
 	int hdrlen;
 	int ret;
 
-	if (has_loose_object(oid->hash))
+	if (has_loose_object(oid))
 		return 0;
 	buf = read_object(oid->hash, &type, &len);
 	if (!buf)

[PATCH v2 07/42] packfile: convert find_pack_entry to object_id

[brian m. carlson]

Convert find_pack_entry and the static function fill_pack_entry to take
pointers to struct object_id.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 packfile.c  | 12 ++++++------
 packfile.h  |  2 +-
 sha1-file.c |  6 +++---
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/packfile.c b/packfile.c
index e65f943664..84acd405e0 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1805,7 +1805,7 @@ struct packed_git *find_sha1_pack(const unsigned char *sha1,
 
 }
 
-static int fill_pack_entry(const unsigned char *sha1,
+static int fill_pack_entry(const struct object_id *oid,
 			   struct pack_entry *e,
 			   struct packed_git *p)
 {
@@ -1814,11 +1814,11 @@ static int fill_pack_entry(const unsigned char *sha1,
 	if (p->num_bad_objects) {
 		unsigned i;
 		for (i = 0; i < p->num_bad_objects; i++)
-			if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+			if (!hashcmp(oid->hash, p->bad_object_sha1 + 20 * i))
 				return 0;
 	}
 
-	offset = find_pack_entry_one(sha1, p);
+	offset = find_pack_entry_one(oid->hash, p);
 	if (!offset)
 		return 0;
 
@@ -1836,7 +1836,7 @@ static int fill_pack_entry(const unsigned char *sha1,
 	return 1;
 }
 
-int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack_entry *e)
+int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
 {
 	struct list_head *pos;
 
@@ -1846,7 +1846,7 @@ int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack
 
 	list_for_each(pos, &r->objects->packed_git_mru) {
 		struct packed_git *p = list_entry(pos, struct packed_git, mru);
-		if (fill_pack_entry(sha1, e, p)) {
+		if (fill_pack_entry(oid, e, p)) {
 			list_move(&p->mru, &r->objects->packed_git_mru);
 			return 1;
 		}
@@ -1857,7 +1857,7 @@ int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack
 int has_object_pack(const struct object_id *oid)
 {
 	struct pack_entry e;
-	return find_pack_entry(the_repository, oid->hash, &e);
+	return find_pack_entry(the_repository, oid, &e);
 }
 
 int has_pack_index(const unsigned char *sha1)
diff --git a/packfile.h b/packfile.h
index 14ca34bcbd..782029ed07 100644
--- a/packfile.h
+++ b/packfile.h
@@ -134,7 +134,7 @@ extern const struct packed_git *has_packed_and_bad(const unsigned char *sha1);
  * Iff a pack file in the given repository contains the object named by sha1,
  * return true and store its location to e.
  */
-extern int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack_entry *e);
+extern int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e);
 
 extern int has_object_pack(const struct object_id *oid);
 
diff --git a/sha1-file.c b/sha1-file.c
index 1617e25495..4328c61285 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -1268,7 +1268,7 @@ int oid_object_info_extended(const struct object_id *oid, struct object_info *oi
 	}
 
 	while (1) {
-		if (find_pack_entry(the_repository, real->hash, &e))
+		if (find_pack_entry(the_repository, real, &e))
 			break;
 
 		if (flags & OBJECT_INFO_IGNORE_LOOSE)
@@ -1281,7 +1281,7 @@ int oid_object_info_extended(const struct object_id *oid, struct object_info *oi
 		/* Not a loose object; someone else may have just packed it. */
 		if (!(flags & OBJECT_INFO_QUICK)) {
 			reprepare_packed_git(the_repository);
-			if (find_pack_entry(the_repository, real->hash, &e))
+			if (find_pack_entry(the_repository, real, &e))
 				break;
 		}
 
@@ -1669,7 +1669,7 @@ static int freshen_loose_object(const struct object_id *oid)
 static int freshen_packed_object(const struct object_id *oid)
 {
 	struct pack_entry e;
-	if (!find_pack_entry(the_repository, oid->hash, &e))
+	if (!find_pack_entry(the_repository, oid, &e))
 		return 0;
 	if (e.p->freshened)
 		return 1;

[PATCH v2 08/42] packfile: abstract away hash constant values

[brian m. carlson]

There are several instances of the constant 20 and 20-based values in
the packfile code.  Abstract away dependence on SHA-1 by using the
values from the_hash_algo instead.

Use unsigned values for temporary constants to provide the compiler with
more information about what kinds of values it should expect.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 packfile.c | 66 ++++++++++++++++++++++++++++++------------------------
 1 file changed, 37 insertions(+), 29 deletions(-)

diff --git a/packfile.c b/packfile.c
index 84acd405e0..b7bc4eab17 100644
--- a/packfile.c
+++ b/packfile.c
@@ -84,6 +84,7 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
 	uint32_t version, nr, i, *index;
 	int fd = git_open(path);
 	struct stat st;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	if (fd < 0)
 		return -1;
@@ -92,7 +93,7 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
 		return -1;
 	}
 	idx_size = xsize_t(st.st_size);
-	if (idx_size < 4 * 256 + 20 + 20) {
+	if (idx_size < 4 * 256 + hashsz + hashsz) {
 		close(fd);
 		return error("index file %s is too small", path);
 	}
@@ -129,11 +130,11 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
 		/*
 		 * Total size:
 		 *  - 256 index entries 4 bytes each
-		 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
-		 *  - 20-byte SHA1 of the packfile
-		 *  - 20-byte SHA1 file checksum
+		 *  - 24-byte entries * nr (object ID + 4-byte offset)
+		 *  - hash of the packfile
+		 *  - file checksum
 		 */
-		if (idx_size != 4*256 + nr * 24 + 20 + 20) {
+		if (idx_size != 4*256 + nr * (hashsz + 4) + hashsz + hashsz) {
 			munmap(idx_map, idx_size);
 			return error("wrong index v1 file size in %s", path);
 		}
@@ -142,16 +143,16 @@ static int check_packed_git_idx(const char *path, struct packed_git *p)
 		 * Minimum size:
 		 *  - 8 bytes of header
 		 *  - 256 index entries 4 bytes each
-		 *  - 20-byte sha1 entry * nr
+		 *  - object ID entry * nr
 		 *  - 4-byte crc entry * nr
 		 *  - 4-byte offset entry * nr
-		 *  - 20-byte SHA1 of the packfile
-		 *  - 20-byte SHA1 file checksum
+		 *  - hash of the packfile
+		 *  - file checksum
 		 * And after the 4-byte offset table might be a
 		 * variable sized table containing 8-byte entries
 		 * for offsets larger than 2^31.
 		 */
-		unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
+		unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 		unsigned long max_size = min_size;
 		if (nr)
 			max_size += (nr - 1)*8;
@@ -444,10 +445,11 @@ static int open_packed_git_1(struct packed_git *p)
 {
 	struct stat st;
 	struct pack_header hdr;
-	unsigned char sha1[20];
-	unsigned char *idx_sha1;
+	unsigned char hash[GIT_MAX_RAWSZ];
+	unsigned char *idx_hash;
 	long fd_flag;
 	ssize_t read_result;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	if (!p->index_data && open_pack_index(p))
 		return error("packfile %s index unavailable", p->pack_name);
@@ -507,15 +509,15 @@ static int open_packed_git_1(struct packed_git *p)
 			     " while index indicates %"PRIu32" objects",
 			     p->pack_name, ntohl(hdr.hdr_entries),
 			     p->num_objects);
-	if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
+	if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 		return error("end of packfile %s is unavailable", p->pack_name);
-	read_result = read_in_full(p->pack_fd, sha1, sizeof(sha1));
+	read_result = read_in_full(p->pack_fd, hash, hashsz);
 	if (read_result < 0)
 		return error_errno("error reading from %s", p->pack_name);
-	if (read_result != sizeof(sha1))
+	if (read_result != hashsz)
 		return error("packfile %s signature is unavailable", p->pack_name);
-	idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
-	if (hashcmp(sha1, idx_sha1))
+	idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
+	if (hashcmp(hash, idx_hash))
 		return error("packfile %s does not match index", p->pack_name);
 	return 0;
 }
@@ -530,7 +532,7 @@ static int open_packed_git(struct packed_git *p)
 
 static int in_window(struct pack_window *win, off_t offset)
 {
-	/* We must promise at least 20 bytes (one hash) after the
+	/* We must promise at least one full hash after the
 	 * offset is available from this window, otherwise the offset
 	 * is not actually in this window and a different window (which
 	 * has that one hash excess) must be used.  This is to support
@@ -538,7 +540,7 @@ static int in_window(struct pack_window *win, off_t offset)
 	 */
 	off_t win_off = win->offset;
 	return win_off <= offset
-		&& (offset + 20) <= (win_off + win->len);
+		&& (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 }
 
 unsigned char *use_pack(struct packed_git *p,
@@ -555,7 +557,7 @@ unsigned char *use_pack(struct packed_git *p,
 	 */
 	if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 		die("packfile %s cannot be accessed", p->pack_name);
-	if (offset > (p->pack_size - 20))
+	if (offset > (p->pack_size - the_hash_algo->rawsz))
 		die("offset beyond end of packfile (truncated pack?)");
 	if (offset < 0)
 		die(_("offset before end of packfile (broken .idx?)"));
@@ -675,7 +677,8 @@ struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 	p->pack_size = st.st_size;
 	p->pack_local = local;
 	p->mtime = st.st_mtime;
-	if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
+	if (path_len < the_hash_algo->hexsz ||
+	    get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->sha1))
 		hashclr(p->sha1);
 	return p;
 }
@@ -1028,7 +1031,8 @@ const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
 
 	for (p = the_repository->objects->packed_git; p; p = p->next)
 		for (i = 0; i < p->num_bad_objects; i++)
-			if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+			if (!hashcmp(sha1,
+				     p->bad_object_sha1 + the_hash_algo->rawsz * i))
 				return p;
 	return NULL;
 }
@@ -1066,7 +1070,7 @@ static off_t get_delta_base(struct packed_git *p,
 	} else if (type == OBJ_REF_DELTA) {
 		/* The base entry _must_ be in the same pack */
 		base_offset = find_pack_entry_one(base_info, p);
-		*curpos += 20;
+		*curpos += the_hash_algo->rawsz;
 	} else
 		die("I am totally screwed");
 	return base_offset;
@@ -1671,6 +1675,7 @@ int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32
 {
 	const unsigned char *index_fanout = p->index_data;
 	const unsigned char *index_lookup;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 	int index_lookup_width;
 
 	if (!index_fanout)
@@ -1678,10 +1683,10 @@ int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32
 
 	index_lookup = index_fanout + 4 * 256;
 	if (p->index_version == 1) {
-		index_lookup_width = 24;
+		index_lookup_width = hashsz + 4;
 		index_lookup += 4;
 	} else {
-		index_lookup_width = 20;
+		index_lookup_width = hashsz;
 		index_fanout += 8;
 		index_lookup += 8;
 	}
@@ -1694,6 +1699,7 @@ const unsigned char *nth_packed_object_sha1(struct packed_git *p,
 					    uint32_t n)
 {
 	const unsigned char *index = p->index_data;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 	if (!index) {
 		if (open_pack_index(p))
 			return NULL;
@@ -1703,10 +1709,10 @@ const unsigned char *nth_packed_object_sha1(struct packed_git *p,
 		return NULL;
 	index += 4 * 256;
 	if (p->index_version == 1) {
-		return index + 24 * n + 4;
+		return index + (hashsz + 4) * n + 4;
 	} else {
 		index += 8;
-		return index + 20 * n;
+		return index + hashsz * n;
 	}
 }
 
@@ -1738,12 +1744,13 @@ void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
 {
 	const unsigned char *index = p->index_data;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 	index += 4 * 256;
 	if (p->index_version == 1) {
-		return ntohl(*((uint32_t *)(index + 24 * n)));
+		return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
 	} else {
 		uint32_t off;
-		index += 8 + p->num_objects * (20 + 4);
+		index += 8 + p->num_objects * (hashsz + 4);
 		off = ntohl(*((uint32_t *)(index + 4 * n)));
 		if (!(off & 0x80000000))
 			return off;
@@ -1814,7 +1821,8 @@ static int fill_pack_entry(const struct object_id *oid,
 	if (p->num_bad_objects) {
 		unsigned i;
 		for (i = 0; i < p->num_bad_objects; i++)
-			if (!hashcmp(oid->hash, p->bad_object_sha1 + 20 * i))
+			if (!hashcmp(oid->hash,
+				     p->bad_object_sha1 + the_hash_algo->rawsz * i))
 				return 0;
 	}
 

[PATCH v2 09/42] pack-objects: abstract away hash algorithm

[brian m. carlson]

Instead of using hard-coded instances of the constant 20, use
the_hash_algo to look up the correct constant.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/pack-objects.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 907e112331..f014523613 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -264,6 +264,7 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
 	enum object_type type;
 	void *buf;
 	struct git_istream *st = NULL;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	if (!usable_delta) {
 		if (entry->type == OBJ_BLOB &&
@@ -320,7 +321,7 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
 		dheader[pos] = ofs & 127;
 		while (ofs >>= 7)
 			dheader[--pos] = 128 | (--ofs & 127);
-		if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+		if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
@@ -332,19 +333,19 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
 	} else if (type == OBJ_REF_DELTA) {
 		/*
 		 * Deltas with a base reference contain
-		 * an additional 20 bytes for the base sha1.
+		 * additional bytes for the base object ID.
 		 */
-		if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+		if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
 			return 0;
 		}
 		hashwrite(f, header, hdrlen);
-		hashwrite(f, entry->delta->idx.oid.hash, 20);
-		hdrlen += 20;
+		hashwrite(f, entry->delta->idx.oid.hash, hashsz);
+		hdrlen += hashsz;
 	} else {
-		if (limit && hdrlen + datalen + 20 >= limit) {
+		if (limit && hdrlen + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
@@ -376,6 +377,7 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 	unsigned char header[MAX_PACK_OBJECT_HEADER],
 		      dheader[MAX_PACK_OBJECT_HEADER];
 	unsigned hdrlen;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	if (entry->delta)
 		type = (allow_ofs_delta && entry->delta->idx.offset) ?
@@ -411,7 +413,7 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 		dheader[pos] = ofs & 127;
 		while (ofs >>= 7)
 			dheader[--pos] = 128 | (--ofs & 127);
-		if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+		if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
@@ -420,16 +422,16 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 		hdrlen += sizeof(dheader) - pos;
 		reused_delta++;
 	} else if (type == OBJ_REF_DELTA) {
-		if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+		if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
 		hashwrite(f, header, hdrlen);
-		hashwrite(f, entry->delta->idx.oid.hash, 20);
-		hdrlen += 20;
+		hashwrite(f, entry->delta->idx.oid.hash, hashsz);
+		hdrlen += hashsz;
 		reused_delta++;
 	} else {
-		if (limit && hdrlen + datalen + 20 >= limit) {
+		if (limit && hdrlen + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
@@ -752,7 +754,7 @@ static off_t write_reused_pack(struct hashfile *f)
 		die_errno("unable to seek in reused packfile");
 
 	if (reuse_packfile_offset < 0)
-		reuse_packfile_offset = reuse_packfile->pack_size - 20;
+		reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 
 	total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 
@@ -1438,7 +1440,7 @@ static void check_object(struct object_entry *entry)
 			if (reuse_delta && !entry->preferred_base)
 				base_ref = use_pack(p, &w_curs,
 						entry->in_pack_offset + used, NULL);
-			entry->in_pack_header_size = used + 20;
+			entry->in_pack_header_size = used + the_hash_algo->rawsz;
 			break;
 		case OBJ_OFS_DELTA:
 			buf = use_pack(p, &w_curs,
@@ -1850,7 +1852,7 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
 	/* Now some size filtering heuristics. */
 	trg_size = trg_entry->size;
 	if (!trg_entry->delta) {
-		max_size = trg_size/2 - 20;
+		max_size = trg_size/2 - the_hash_algo->rawsz;
 		ref_depth = 1;
 	} else {
 		max_size = trg_entry->delta_size;

[PATCH v2 10/42] pack-redundant: abstract away hash algorithm

[brian m. carlson]

Instead of using hard-coded instances of the constant 20, use
the_hash_algo to look up the correct constant.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/pack-redundant.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c
index 354478a127..0fe1ff3cb7 100644
--- a/builtin/pack-redundant.c
+++ b/builtin/pack-redundant.c
@@ -252,13 +252,14 @@ static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
 	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
 	const unsigned char *p1_base, *p2_base;
 	struct llist_item *p1_hint = NULL, *p2_hint = NULL;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	p1_base = p1->pack->index_data;
 	p2_base = p2->pack->index_data;
 	p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
 	p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
-	p1_step = (p1->pack->index_version < 2) ? 24 : 20;
-	p2_step = (p2->pack->index_version < 2) ? 24 : 20;
+	p1_step = hashsz + ((p1->pack->index_version < 2) ? 4 : 0);
+	p2_step = hashsz + ((p2->pack->index_version < 2) ? 4 : 0);
 
 	while (p1_off < p1->pack->num_objects * p1_step &&
 	       p2_off < p2->pack->num_objects * p2_step)
@@ -359,13 +360,14 @@ static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
 	size_t ret = 0;
 	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
 	const unsigned char *p1_base, *p2_base;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	p1_base = p1->index_data;
 	p2_base = p2->index_data;
 	p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
 	p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
-	p1_step = (p1->index_version < 2) ? 24 : 20;
-	p2_step = (p2->index_version < 2) ? 24 : 20;
+	p1_step = hashsz + ((p1->index_version < 2) ? 4 : 0);
+	p2_step = hashsz + ((p2->index_version < 2) ? 4 : 0);
 
 	while (p1_off < p1->num_objects * p1_step &&
 	       p2_off < p2->num_objects * p2_step)
@@ -558,7 +560,7 @@ static struct pack_list * add_pack(struct packed_git *p)
 
 	base = p->index_data;
 	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
-	step = (p->index_version < 2) ? 24 : 20;
+	step = the_hash_algo->rawsz + ((p->index_version < 2) ? 4 : 0);
 	while (off < p->num_objects * step) {
 		llist_insert_back(l.all_objects, base + off);
 		off += step;

[PATCH v2 11/42] tree-walk: avoid hard-coded 20 constant

[brian m. carlson]

Use the_hash_algo to look up the length of our current hash instead of
hard-coding the value 20.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 tree-walk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tree-walk.c b/tree-walk.c
index e11b3063af..27797c5406 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -105,7 +105,7 @@ static void entry_extract(struct tree_desc *t, struct name_entry *a)
 static int update_tree_entry_internal(struct tree_desc *desc, struct strbuf *err)
 {
 	const void *buf = desc->buffer;
-	const unsigned char *end = desc->entry.oid->hash + 20;
+	const unsigned char *end = desc->entry.oid->hash + the_hash_algo->rawsz;
 	unsigned long size = desc->size;
 	unsigned long len = end - (const unsigned char *)buf;
 

[PATCH v2 12/42] tree-walk: convert get_tree_entry_follow_symlinks to object_id

[brian m. carlson]

Since the only caller of this function already uses struct object_id,
update get_tree_entry_follow_symlinks to use it in parameters and
internally.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 sha1-name.c |  4 ++--
 tree-walk.c | 16 ++++++++--------
 tree-walk.h |  2 +-
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/sha1-name.c b/sha1-name.c
index 7043652a24..7c2d08a202 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -1685,8 +1685,8 @@ static int get_oid_with_context_1(const char *name,
 			if (new_filename)
 				filename = new_filename;
 			if (flags & GET_OID_FOLLOW_SYMLINKS) {
-				ret = get_tree_entry_follow_symlinks(tree_oid.hash,
-					filename, oid->hash, &oc->symlink_path,
+				ret = get_tree_entry_follow_symlinks(&tree_oid,
+					filename, oid, &oc->symlink_path,
 					&oc->mode);
 			} else {
 				ret = get_tree_entry(&tree_oid, filename, oid,
diff --git a/tree-walk.c b/tree-walk.c
index 27797c5406..8f5090862b 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -488,7 +488,7 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 struct dir_state {
 	void *tree;
 	unsigned long size;
-	unsigned char sha1[20];
+	struct object_id oid;
 };
 
 static int find_tree_entry(struct tree_desc *t, const char *name, struct object_id *result, unsigned *mode)
@@ -576,7 +576,7 @@ int get_tree_entry(const struct object_id *tree_oid, const char *name, struct ob
  * See the code for enum follow_symlink_result for a description of
  * the return values.
  */
-enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_sha1, const char *name, unsigned char *result, struct strbuf *result_path, unsigned *mode)
+enum follow_symlinks_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode)
 {
 	int retval = MISSING_OBJECT;
 	struct dir_state *parents = NULL;
@@ -589,7 +589,7 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s
 
 	init_tree_desc(&t, NULL, 0UL);
 	strbuf_addstr(&namebuf, name);
-	hashcpy(current_tree_oid.hash, tree_sha1);
+	oidcpy(&current_tree_oid, tree_oid);
 
 	while (1) {
 		int find_result;
@@ -609,11 +609,11 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s
 			ALLOC_GROW(parents, parents_nr + 1, parents_alloc);
 			parents[parents_nr].tree = tree;
 			parents[parents_nr].size = size;
-			hashcpy(parents[parents_nr].sha1, root.hash);
+			oidcpy(&parents[parents_nr].oid, &root);
 			parents_nr++;
 
 			if (namebuf.buf[0] == '\0') {
-				hashcpy(result, root.hash);
+				oidcpy(result, &root);
 				retval = FOUND;
 				goto done;
 			}
@@ -663,7 +663,7 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s
 
 		/* We could end up here via a symlink to dir/.. */
 		if (namebuf.buf[0] == '\0') {
-			hashcpy(result, parents[parents_nr - 1].sha1);
+			oidcpy(result, &parents[parents_nr - 1].oid);
 			retval = FOUND;
 			goto done;
 		}
@@ -677,7 +677,7 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s
 
 		if (S_ISDIR(*mode)) {
 			if (!remainder) {
-				hashcpy(result, current_tree_oid.hash);
+				oidcpy(result, &current_tree_oid);
 				retval = FOUND;
 				goto done;
 			}
@@ -687,7 +687,7 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s
 				      1 + first_slash - namebuf.buf);
 		} else if (S_ISREG(*mode)) {
 			if (!remainder) {
-				hashcpy(result, current_tree_oid.hash);
+				oidcpy(result, &current_tree_oid);
 				retval = FOUND;
 			} else {
 				retval = NOT_DIR;
diff --git a/tree-walk.h b/tree-walk.h
index 4617deeb0e..805f58f00f 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -64,7 +64,7 @@ enum follow_symlinks_result {
 		       */
 };
 
-enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_sha1, const char *name, unsigned char *result, struct strbuf *result_path, unsigned *mode);
+enum follow_symlinks_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode);
 
 struct traverse_info {
 	const char *traverse_path;

[PATCH v2 13/42] fsck: convert static functions to struct object_id

[brian m. carlson]

Convert two static functions to use struct object_id and parse_oid_hex,
instead of relying on harcoded 20 and 40-based constants.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 fsck.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/fsck.c b/fsck.c
index 9218c2a643..768011f812 100644
--- a/fsck.c
+++ b/fsck.c
@@ -711,30 +711,31 @@ static int fsck_ident(const char **ident, struct object *obj, struct fsck_option
 static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 	unsigned long size, struct fsck_options *options)
 {
-	unsigned char tree_sha1[20], sha1[20];
+	struct object_id tree_oid, oid;
 	struct commit_graft *graft;
 	unsigned parent_count, parent_line_count = 0, author_count;
 	int err;
 	const char *buffer_begin = buffer;
+	const char *p;
 
 	if (verify_headers(buffer, size, &commit->object, options))
 		return -1;
 
 	if (!skip_prefix(buffer, "tree ", &buffer))
 		return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
-	if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n') {
+	if (parse_oid_hex(buffer, &tree_oid, &p) || *p != '\n') {
 		err = report(options, &commit->object, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
 		if (err)
 			return err;
 	}
-	buffer += 41;
+	buffer = p + 1;
 	while (skip_prefix(buffer, "parent ", &buffer)) {
-		if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
+		if (parse_oid_hex(buffer, &oid, &p) || *p != '\n') {
 			err = report(options, &commit->object, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
 			if (err)
 				return err;
 		}
-		buffer += 41;
+		buffer = p + 1;
 		parent_line_count++;
 	}
 	graft = lookup_commit_graft(&commit->object.oid);
@@ -773,7 +774,7 @@ static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 	if (err)
 		return err;
 	if (!commit->tree) {
-		err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
+		err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", oid_to_hex(&tree_oid));
 		if (err)
 			return err;
 	}
@@ -799,11 +800,12 @@ static int fsck_commit(struct commit *commit, const char *data,
 static int fsck_tag_buffer(struct tag *tag, const char *data,
 	unsigned long size, struct fsck_options *options)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	int ret = 0;
 	const char *buffer;
 	char *to_free = NULL, *eol;
 	struct strbuf sb = STRBUF_INIT;
+	const char *p;
 
 	if (data)
 		buffer = data;
@@ -834,12 +836,12 @@ static int fsck_tag_buffer(struct tag *tag, const char *data,
 		ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 		goto done;
 	}
-	if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
+	if (parse_oid_hex(buffer, &oid, &p) || *p != '\n') {
 		ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 		if (ret)
 			goto done;
 	}
-	buffer += 41;
+	buffer = p + 1;
 
 	if (!skip_prefix(buffer, "type ", &buffer)) {
 		ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");

[PATCH v2 14/42] submodule-config: convert structures to object_id

[brian m. carlson]

Convert struct submodule and struct parse_config_parameter to use struct
object_id.  Adjust the functions which take members of these structures
as arguments to also use struct object_id.  Include cache.h into
submodule-config.h to make struct object_id visible.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 submodule-config.c | 66 +++++++++++++++++++++++-----------------------
 submodule-config.h |  7 ++---
 2 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/submodule-config.c b/submodule-config.c
index 3f2075764f..5537c88727 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -44,7 +44,7 @@ static int config_path_cmp(const void *unused_cmp_data,
 	const struct submodule_entry *b = entry_or_key;
 
 	return strcmp(a->config->path, b->config->path) ||
-	       hashcmp(a->config->gitmodules_sha1, b->config->gitmodules_sha1);
+	       oidcmp(&a->config->gitmodules_oid, &b->config->gitmodules_oid);
 }
 
 static int config_name_cmp(const void *unused_cmp_data,
@@ -56,7 +56,7 @@ static int config_name_cmp(const void *unused_cmp_data,
 	const struct submodule_entry *b = entry_or_key;
 
 	return strcmp(a->config->name, b->config->name) ||
-	       hashcmp(a->config->gitmodules_sha1, b->config->gitmodules_sha1);
+	       oidcmp(&a->config->gitmodules_oid, &b->config->gitmodules_oid);
 }
 
 static struct submodule_cache *submodule_cache_alloc(void)
@@ -109,17 +109,17 @@ void submodule_cache_free(struct submodule_cache *cache)
 	free(cache);
 }
 
-static unsigned int hash_sha1_string(const unsigned char *sha1,
-				     const char *string)
+static unsigned int hash_oid_string(const struct object_id *oid,
+				    const char *string)
 {
-	return memhash(sha1, 20) + strhash(string);
+	return memhash(oid->hash, the_hash_algo->rawsz) + strhash(string);
 }
 
 static void cache_put_path(struct submodule_cache *cache,
 			   struct submodule *submodule)
 {
-	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
-					     submodule->path);
+	unsigned int hash = hash_oid_string(&submodule->gitmodules_oid,
+					    submodule->path);
 	struct submodule_entry *e = xmalloc(sizeof(*e));
 	hashmap_entry_init(e, hash);
 	e->config = submodule;
@@ -129,8 +129,8 @@ static void cache_put_path(struct submodule_cache *cache,
 static void cache_remove_path(struct submodule_cache *cache,
 			      struct submodule *submodule)
 {
-	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
-					     submodule->path);
+	unsigned int hash = hash_oid_string(&submodule->gitmodules_oid,
+					    submodule->path);
 	struct submodule_entry e;
 	struct submodule_entry *removed;
 	hashmap_entry_init(&e, hash);
@@ -142,8 +142,8 @@ static void cache_remove_path(struct submodule_cache *cache,
 static void cache_add(struct submodule_cache *cache,
 		      struct submodule *submodule)
 {
-	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
-					     submodule->name);
+	unsigned int hash = hash_oid_string(&submodule->gitmodules_oid,
+					    submodule->name);
 	struct submodule_entry *e = xmalloc(sizeof(*e));
 	hashmap_entry_init(e, hash);
 	e->config = submodule;
@@ -151,14 +151,14 @@ static void cache_add(struct submodule_cache *cache,
 }
 
 static const struct submodule *cache_lookup_path(struct submodule_cache *cache,
-		const unsigned char *gitmodules_sha1, const char *path)
+		const struct object_id *gitmodules_oid, const char *path)
 {
 	struct submodule_entry *entry;
-	unsigned int hash = hash_sha1_string(gitmodules_sha1, path);
+	unsigned int hash = hash_oid_string(gitmodules_oid, path);
 	struct submodule_entry key;
 	struct submodule key_config;
 
-	hashcpy(key_config.gitmodules_sha1, gitmodules_sha1);
+	oidcpy(&key_config.gitmodules_oid, gitmodules_oid);
 	key_config.path = path;
 
 	hashmap_entry_init(&key, hash);
@@ -171,14 +171,14 @@ static const struct submodule *cache_lookup_path(struct submodule_cache *cache,
 }
 
 static struct submodule *cache_lookup_name(struct submodule_cache *cache,
-		const unsigned char *gitmodules_sha1, const char *name)
+		const struct object_id *gitmodules_oid, const char *name)
 {
 	struct submodule_entry *entry;
-	unsigned int hash = hash_sha1_string(gitmodules_sha1, name);
+	unsigned int hash = hash_oid_string(gitmodules_oid, name);
 	struct submodule_entry key;
 	struct submodule key_config;
 
-	hashcpy(key_config.gitmodules_sha1, gitmodules_sha1);
+	oidcpy(&key_config.gitmodules_oid, gitmodules_oid);
 	key_config.name = name;
 
 	hashmap_entry_init(&key, hash);
@@ -207,12 +207,12 @@ static int name_and_item_from_var(const char *var, struct strbuf *name,
 }
 
 static struct submodule *lookup_or_create_by_name(struct submodule_cache *cache,
-		const unsigned char *gitmodules_sha1, const char *name)
+		const struct object_id *gitmodules_oid, const char *name)
 {
 	struct submodule *submodule;
 	struct strbuf name_buf = STRBUF_INIT;
 
-	submodule = cache_lookup_name(cache, gitmodules_sha1, name);
+	submodule = cache_lookup_name(cache, gitmodules_oid, name);
 	if (submodule)
 		return submodule;
 
@@ -230,7 +230,7 @@ static struct submodule *lookup_or_create_by_name(struct submodule_cache *cache,
 	submodule->branch = NULL;
 	submodule->recommend_shallow = -1;
 
-	hashcpy(submodule->gitmodules_sha1, gitmodules_sha1);
+	oidcpy(&submodule->gitmodules_oid, gitmodules_oid);
 
 	cache_add(cache, submodule);
 
@@ -341,12 +341,12 @@ int parse_push_recurse_submodules_arg(const char *opt, const char *arg)
 	return parse_push_recurse(opt, arg, 1);
 }
 
-static void warn_multiple_config(const unsigned char *treeish_name,
+static void warn_multiple_config(const struct object_id *treeish_name,
 				 const char *name, const char *option)
 {
 	const char *commit_string = "WORKTREE";
 	if (treeish_name)
-		commit_string = sha1_to_hex(treeish_name);
+		commit_string = oid_to_hex(treeish_name);
 	warning("%s:.gitmodules, multiple configurations found for "
 			"'submodule.%s.%s'. Skipping second one!",
 			commit_string, name, option);
@@ -354,8 +354,8 @@ static void warn_multiple_config(const unsigned char *treeish_name,
 
 struct parse_config_parameter {
 	struct submodule_cache *cache;
-	const unsigned char *treeish_name;
-	const unsigned char *gitmodules_sha1;
+	const struct object_id *treeish_name;
+	const struct object_id *gitmodules_oid;
 	int overwrite;
 };
 
@@ -371,7 +371,7 @@ static int parse_config(const char *var, const char *value, void *data)
 		return 0;
 
 	submodule = lookup_or_create_by_name(me->cache,
-					     me->gitmodules_sha1,
+					     me->gitmodules_oid,
 					     name.buf);
 
 	if (!strcmp(item.buf, "path")) {
@@ -389,7 +389,7 @@ static int parse_config(const char *var, const char *value, void *data)
 		}
 	} else if (!strcmp(item.buf, "fetchrecursesubmodules")) {
 		/* when parsing worktree configurations we can die early */
-		int die_on_error = is_null_sha1(me->gitmodules_sha1);
+		int die_on_error = is_null_oid(me->gitmodules_oid);
 		if (!me->overwrite &&
 		    submodule->fetch_recurse != RECURSE_SUBMODULES_NONE)
 			warn_multiple_config(me->treeish_name, submodule->name,
@@ -511,10 +511,10 @@ static const struct submodule *config_from(struct submodule_cache *cache,
 
 	switch (lookup_type) {
 	case lookup_name:
-		submodule = cache_lookup_name(cache, oid.hash, key);
+		submodule = cache_lookup_name(cache, &oid, key);
 		break;
 	case lookup_path:
-		submodule = cache_lookup_path(cache, oid.hash, key);
+		submodule = cache_lookup_path(cache, &oid, key);
 		break;
 	}
 	if (submodule)
@@ -526,8 +526,8 @@ static const struct submodule *config_from(struct submodule_cache *cache,
 
 	/* fill the submodule config into the cache */
 	parameter.cache = cache;
-	parameter.treeish_name = treeish_name->hash;
-	parameter.gitmodules_sha1 = oid.hash;
+	parameter.treeish_name = treeish_name;
+	parameter.gitmodules_oid = &oid;
 	parameter.overwrite = 0;
 	git_config_from_mem(parse_config, CONFIG_ORIGIN_SUBMODULE_BLOB, rev.buf,
 			config, config_size, &parameter);
@@ -536,9 +536,9 @@ static const struct submodule *config_from(struct submodule_cache *cache,
 
 	switch (lookup_type) {
 	case lookup_name:
-		return cache_lookup_name(cache, oid.hash, key);
+		return cache_lookup_name(cache, &oid, key);
 	case lookup_path:
-		return cache_lookup_path(cache, oid.hash, key);
+		return cache_lookup_path(cache, &oid, key);
 	default:
 		return NULL;
 	}
@@ -567,7 +567,7 @@ static int gitmodules_cb(const char *var, const char *value, void *data)
 
 	parameter.cache = repo->submodule_cache;
 	parameter.treeish_name = NULL;
-	parameter.gitmodules_sha1 = null_sha1;
+	parameter.gitmodules_oid = &null_oid;
 	parameter.overwrite = 1;
 
 	return parse_config(var, value, &parameter);
diff --git a/submodule-config.h b/submodule-config.h
index a5503a5d17..11729fbc74 100644
--- a/submodule-config.h
+++ b/submodule-config.h
@@ -1,6 +1,7 @@
 #ifndef SUBMODULE_CONFIG_CACHE_H
 #define SUBMODULE_CONFIG_CACHE_H
 
+#include "cache.h"
 #include "hashmap.h"
 #include "submodule.h"
 #include "strbuf.h"
@@ -17,13 +18,13 @@ struct submodule {
 	const char *ignore;
 	const char *branch;
 	struct submodule_update_strategy update_strategy;
-	/* the sha1 blob id of the responsible .gitmodules file */
-	unsigned char gitmodules_sha1[20];
+	/* the object id of the responsible .gitmodules file */
+	struct object_id gitmodules_oid;
 	int recommend_shallow;
 };
 
 #define SUBMODULE_INIT { NULL, NULL, NULL, RECURSE_SUBMODULES_NONE, \
-	NULL, NULL, SUBMODULE_UPDATE_STRATEGY_INIT, {0}, -1 };
+	NULL, NULL, SUBMODULE_UPDATE_STRATEGY_INIT, { { 0 } }, -1 };
 
 struct submodule_cache;
 struct repository;

[PATCH v2 15/42] split-index: convert struct split_index to object_id

[brian m. carlson]

Convert the base_sha1 member of struct split_index to use struct
object_id and rename it base_oid.  Include cache.h to make the structure
visible.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/rev-parse.c              |  4 ++--
 read-cache.c                     | 22 +++++++++++-----------
 split-index.c                    | 10 +++++-----
 split-index.h                    |  4 +++-
 t/helper/test-dump-split-index.c |  2 +-
 5 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 36b2087782..55c0b90441 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -887,8 +887,8 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				if (read_cache() < 0)
 					die(_("Could not read the index"));
 				if (the_index.split_index) {
-					const unsigned char *sha1 = the_index.split_index->base_sha1;
-					const char *path = git_path("sharedindex.%s", sha1_to_hex(sha1));
+					const struct object_id *oid = &the_index.split_index->base_oid;
+					const char *path = git_path("sharedindex.%s", oid_to_hex(oid));
 					strbuf_reset(&buf);
 					puts(relative_path(path, prefix, &buf));
 				}
diff --git a/read-cache.c b/read-cache.c
index 10f1c6bb8a..f47666b975 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1878,7 +1878,7 @@ int read_index_from(struct index_state *istate, const char *path,
 	uint64_t start = getnanotime();
 	struct split_index *split_index;
 	int ret;
-	char *base_sha1_hex;
+	char *base_oid_hex;
 	char *base_path;
 
 	/* istate->initialized covers both .git/index and .git/sharedindex.xxx */
@@ -1889,7 +1889,7 @@ int read_index_from(struct index_state *istate, const char *path,
 	trace_performance_since(start, "read cache %s", path);
 
 	split_index = istate->split_index;
-	if (!split_index || is_null_sha1(split_index->base_sha1)) {
+	if (!split_index || is_null_oid(&split_index->base_oid)) {
 		post_read_index_from(istate);
 		return ret;
 	}
@@ -1899,12 +1899,12 @@ int read_index_from(struct index_state *istate, const char *path,
 	else
 		split_index->base = xcalloc(1, sizeof(*split_index->base));
 
-	base_sha1_hex = sha1_to_hex(split_index->base_sha1);
-	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_sha1_hex);
+	base_oid_hex = oid_to_hex(&split_index->base_oid);
+	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex);
 	ret = do_read_index(split_index->base, base_path, 1);
-	if (hashcmp(split_index->base_sha1, split_index->base->sha1))
+	if (hashcmp(split_index->base_oid.hash, split_index->base->sha1))
 		die("broken index, expect %s in %s, got %s",
-		    base_sha1_hex, base_path,
+		    base_oid_hex, base_path,
 		    sha1_to_hex(split_index->base->sha1));
 
 	freshen_shared_index(base_path, 0);
@@ -2499,7 +2499,7 @@ static int write_shared_index(struct index_state *istate,
 	ret = rename_tempfile(temp,
 			      git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
 	if (!ret) {
-		hashcpy(si->base_sha1, si->base->sha1);
+		hashcpy(si->base_oid.hash, si->base->sha1);
 		clean_shared_index_files(sha1_to_hex(si->base->sha1));
 	}
 
@@ -2554,13 +2554,13 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 	if (!si || alternate_index_output ||
 	    (istate->cache_changed & ~EXTMASK)) {
 		if (si)
-			hashclr(si->base_sha1);
+			oidclr(&si->base_oid);
 		ret = do_write_locked_index(istate, lock, flags);
 		goto out;
 	}
 
 	if (getenv("GIT_TEST_SPLIT_INDEX")) {
-		int v = si->base_sha1[0];
+		int v = si->base_oid.hash[0];
 		if ((v & 15) < 6)
 			istate->cache_changed |= SPLIT_INDEX_ORDERED;
 	}
@@ -2575,7 +2575,7 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 
 		temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
 		if (!temp) {
-			hashclr(si->base_sha1);
+			oidclr(&si->base_oid);
 			ret = do_write_locked_index(istate, lock, flags);
 			goto out;
 		}
@@ -2595,7 +2595,7 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 	/* Freshen the shared index only if the split-index was written */
 	if (!ret && !new_shared_index) {
 		const char *shared_index = git_path("sharedindex.%s",
-						    sha1_to_hex(si->base_sha1));
+						    oid_to_hex(&si->base_oid));
 		freshen_shared_index(shared_index, 1);
 	}
 
diff --git a/split-index.c b/split-index.c
index 3eb8ff1b43..660c75f31f 100644
--- a/split-index.c
+++ b/split-index.c
@@ -18,12 +18,12 @@ int read_link_extension(struct index_state *istate,
 	struct split_index *si;
 	int ret;
 
-	if (sz < 20)
+	if (sz < the_hash_algo->rawsz)
 		return error("corrupt link extension (too short)");
 	si = init_split_index(istate);
-	hashcpy(si->base_sha1, data);
-	data += 20;
-	sz -= 20;
+	hashcpy(si->base_oid.hash, data);
+	data += the_hash_algo->rawsz;
+	sz -= the_hash_algo->rawsz;
 	if (!sz)
 		return 0;
 	si->delete_bitmap = ewah_new();
@@ -45,7 +45,7 @@ int write_link_extension(struct strbuf *sb,
 			 struct index_state *istate)
 {
 	struct split_index *si = istate->split_index;
-	strbuf_add(sb, si->base_sha1, 20);
+	strbuf_add(sb, si->base_oid.hash, the_hash_algo->rawsz);
 	if (!si->delete_bitmap && !si->replace_bitmap)
 		return 0;
 	ewah_serialize_strbuf(si->delete_bitmap, sb);
diff --git a/split-index.h b/split-index.h
index 43d66826eb..7a435ca2c9 100644
--- a/split-index.h
+++ b/split-index.h
@@ -1,12 +1,14 @@
 #ifndef SPLIT_INDEX_H
 #define SPLIT_INDEX_H
 
+#include "cache.h"
+
 struct index_state;
 struct strbuf;
 struct ewah_bitmap;
 
 struct split_index {
-	unsigned char base_sha1[20];
+	struct object_id base_oid;
 	struct index_state *base;
 	struct ewah_bitmap *delete_bitmap;
 	struct ewah_bitmap *replace_bitmap;
diff --git a/t/helper/test-dump-split-index.c b/t/helper/test-dump-split-index.c
index 4e2fdb5e30..754e9bb624 100644
--- a/t/helper/test-dump-split-index.c
+++ b/t/helper/test-dump-split-index.c
@@ -20,7 +20,7 @@ int cmd__dump_split_index(int ac, const char **av)
 		printf("not a split index\n");
 		return 0;
 	}
-	printf("base %s\n", sha1_to_hex(si->base_sha1));
+	printf("base %s\n", oid_to_hex(&si->base_oid));
 	for (i = 0; i < the_index.cache_nr; i++) {
 		struct cache_entry *ce = the_index.cache[i];
 		printf("%06o %s %d\t%s\n", ce->ce_mode,

[PATCH v2 16/42] Update struct index_state to use struct object_id

[brian m. carlson]

Adjust struct index_state to use struct object_id instead of unsigned
char [20].

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h                          |  2 +-
 read-cache.c                     | 16 ++++++++--------
 t/helper/test-dump-split-index.c |  2 +-
 unpack-trees.c                   |  2 +-
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/cache.h b/cache.h
index f06737fb78..37d081b8e4 100644
--- a/cache.h
+++ b/cache.h
@@ -324,7 +324,7 @@ struct index_state {
 		 drop_cache_tree : 1;
 	struct hashmap name_hash;
 	struct hashmap dir_hash;
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct untracked_cache *untracked;
 	uint64_t fsmonitor_last_update;
 	struct ewah_bitmap *fsmonitor_dirty;
diff --git a/read-cache.c b/read-cache.c
index f47666b975..9dbaeeec43 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1806,7 +1806,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 	if (verify_hdr(hdr, mmap_size) < 0)
 		goto unmap;
 
-	hashcpy(istate->sha1, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
+	hashcpy(istate->oid.hash, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
 	istate->version = ntohl(hdr->hdr_version);
 	istate->cache_nr = ntohl(hdr->hdr_entries);
 	istate->cache_alloc = alloc_nr(istate->cache_nr);
@@ -1902,10 +1902,10 @@ int read_index_from(struct index_state *istate, const char *path,
 	base_oid_hex = oid_to_hex(&split_index->base_oid);
 	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex);
 	ret = do_read_index(split_index->base, base_path, 1);
-	if (hashcmp(split_index->base_oid.hash, split_index->base->sha1))
+	if (oidcmp(&split_index->base_oid, &split_index->base->oid))
 		die("broken index, expect %s in %s, got %s",
 		    base_oid_hex, base_path,
-		    sha1_to_hex(split_index->base->sha1));
+		    oid_to_hex(&split_index->base->oid));
 
 	freshen_shared_index(base_path, 0);
 	merge_base_index(istate);
@@ -2194,7 +2194,7 @@ static int verify_index_from(const struct index_state *istate, const char *path)
 	if (n != the_hash_algo->rawsz)
 		goto out;
 
-	if (hashcmp(istate->sha1, hash))
+	if (hashcmp(istate->oid.hash, hash))
 		goto out;
 
 	close(fd);
@@ -2373,7 +2373,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
 			return -1;
 	}
 
-	if (ce_flush(&c, newfd, istate->sha1))
+	if (ce_flush(&c, newfd, istate->oid.hash))
 		return -1;
 	if (close_tempfile_gently(tempfile)) {
 		error(_("could not close '%s'"), tempfile->filename.buf);
@@ -2497,10 +2497,10 @@ static int write_shared_index(struct index_state *istate,
 		return ret;
 	}
 	ret = rename_tempfile(temp,
-			      git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
+			      git_path("sharedindex.%s", oid_to_hex(&si->base->oid)));
 	if (!ret) {
-		hashcpy(si->base_oid.hash, si->base->sha1);
-		clean_shared_index_files(sha1_to_hex(si->base->sha1));
+		oidcpy(&si->base_oid, &si->base->oid);
+		clean_shared_index_files(oid_to_hex(&si->base->oid));
 	}
 
 	return ret;
diff --git a/t/helper/test-dump-split-index.c b/t/helper/test-dump-split-index.c
index 754e9bb624..63c689d6ee 100644
--- a/t/helper/test-dump-split-index.c
+++ b/t/helper/test-dump-split-index.c
@@ -14,7 +14,7 @@ int cmd__dump_split_index(int ac, const char **av)
 	int i;
 
 	do_read_index(&the_index, av[1], 1);
-	printf("own %s\n", sha1_to_hex(the_index.sha1));
+	printf("own %s\n", oid_to_hex(&the_index.oid));
 	si = the_index.split_index;
 	if (!si) {
 		printf("not a split index\n");
diff --git a/unpack-trees.c b/unpack-trees.c
index e73745051e..038ef7b926 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1287,7 +1287,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 	o->result.split_index = o->src_index->split_index;
 	if (o->result.split_index)
 		o->result.split_index->refcount++;
-	hashcpy(o->result.sha1, o->src_index->sha1);
+	oidcpy(&o->result.oid, &o->src_index->oid);
 	o->merge_size = len;
 	mark_all_ce_unused(o->src_index);
 

[PATCH v2 17/42] pack-redundant: convert linked lists to use struct object_id

[brian m. carlson]

Convert struct llist_item and the rest of the linked list code to use
struct object_id.  Add a use of GIT_MAX_HEXSZ to avoid a dependency on a
hard-coded constant.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/pack-redundant.c | 50 +++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c
index 0fe1ff3cb7..0494dceff7 100644
--- a/builtin/pack-redundant.c
+++ b/builtin/pack-redundant.c
@@ -20,7 +20,7 @@ static int load_all_packs, verbose, alt_odb;
 
 struct llist_item {
 	struct llist_item *next;
-	const unsigned char *sha1;
+	const struct object_id *oid;
 };
 static struct llist {
 	struct llist_item *front;
@@ -90,14 +90,14 @@ static struct llist * llist_copy(struct llist *list)
 		return ret;
 
 	new_item = ret->front = llist_item_get();
-	new_item->sha1 = list->front->sha1;
+	new_item->oid = list->front->oid;
 
 	old_item = list->front->next;
 	while (old_item) {
 		prev = new_item;
 		new_item = llist_item_get();
 		prev->next = new_item;
-		new_item->sha1 = old_item->sha1;
+		new_item->oid = old_item->oid;
 		old_item = old_item->next;
 	}
 	new_item->next = NULL;
@@ -108,10 +108,10 @@ static struct llist * llist_copy(struct llist *list)
 
 static inline struct llist_item *llist_insert(struct llist *list,
 					      struct llist_item *after,
-					       const unsigned char *sha1)
+					      const struct object_id *oid)
 {
 	struct llist_item *new_item = llist_item_get();
-	new_item->sha1 = sha1;
+	new_item->oid = oid;
 	new_item->next = NULL;
 
 	if (after != NULL) {
@@ -131,21 +131,21 @@ static inline struct llist_item *llist_insert(struct llist *list,
 }
 
 static inline struct llist_item *llist_insert_back(struct llist *list,
-						   const unsigned char *sha1)
+						   const struct object_id *oid)
 {
-	return llist_insert(list, list->back, sha1);
+	return llist_insert(list, list->back, oid);
 }
 
 static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
-			const unsigned char *sha1, struct llist_item *hint)
+			const struct object_id *oid, struct llist_item *hint)
 {
 	struct llist_item *prev = NULL, *l;
 
 	l = (hint == NULL) ? list->front : hint;
 	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
+		int cmp = oidcmp(l->oid, oid);
 		if (cmp > 0) { /* we insert before this entry */
-			return llist_insert(list, prev, sha1);
+			return llist_insert(list, prev, oid);
 		}
 		if (!cmp) { /* already exists */
 			return l;
@@ -154,11 +154,11 @@ static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
 		l = l->next;
 	}
 	/* insert at the end */
-	return llist_insert_back(list, sha1);
+	return llist_insert_back(list, oid);
 }
 
 /* returns a pointer to an item in front of sha1 */
-static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
+static inline struct llist_item * llist_sorted_remove(struct llist *list, const struct object_id *oid, struct llist_item *hint)
 {
 	struct llist_item *prev, *l;
 
@@ -166,7 +166,7 @@ static inline struct llist_item * llist_sorted_remove(struct llist *list, const
 	l = (hint == NULL) ? list->front : hint;
 	prev = NULL;
 	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
+		int cmp = oidcmp(l->oid, oid);
 		if (cmp > 0) /* not in list, since sorted */
 			return prev;
 		if (!cmp) { /* found */
@@ -201,7 +201,7 @@ static void llist_sorted_difference_inplace(struct llist *A,
 	b = B->front;
 
 	while (b) {
-		hint = llist_sorted_remove(A, b->sha1, hint);
+		hint = llist_sorted_remove(A, b->oid, hint);
 		b = b->next;
 	}
 }
@@ -268,9 +268,11 @@ static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
 		/* cmp ~ p1 - p2 */
 		if (cmp == 0) {
 			p1_hint = llist_sorted_remove(p1->unique_objects,
-					p1_base + p1_off, p1_hint);
+					(const struct object_id *)(p1_base + p1_off),
+					p1_hint);
 			p2_hint = llist_sorted_remove(p2->unique_objects,
-					p1_base + p1_off, p2_hint);
+					(const struct object_id *)(p1_base + p1_off),
+					p2_hint);
 			p1_off += p1_step;
 			p2_off += p2_step;
 			continue;
@@ -501,7 +503,7 @@ static void load_all_objects(void)
 		l = pl->all_objects->front;
 		while (l) {
 			hint = llist_insert_sorted_unique(all_objects,
-							  l->sha1, hint);
+							  l->oid, hint);
 			l = l->next;
 		}
 		pl = pl->next;
@@ -562,7 +564,7 @@ static struct pack_list * add_pack(struct packed_git *p)
 	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
 	step = the_hash_algo->rawsz + ((p->index_version < 2) ? 4 : 0);
 	while (off < p->num_objects * step) {
-		llist_insert_back(l.all_objects, base + off);
+		llist_insert_back(l.all_objects, (const struct object_id *)(base + off));
 		off += step;
 	}
 	/* this list will be pruned in cmp_two_packs later */
@@ -603,8 +605,8 @@ int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
 	int i;
 	struct pack_list *min, *red, *pl;
 	struct llist *ignore;
-	unsigned char *sha1;
-	char buf[42]; /* 40 byte sha1 + \n + \0 */
+	struct object_id *oid;
+	char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \n + \0 */
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage(pack_redundant_usage);
@@ -652,10 +654,10 @@ int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
 	llist_init(&ignore);
 	if (!isatty(0)) {
 		while (fgets(buf, sizeof(buf), stdin)) {
-			sha1 = xmalloc(20);
-			if (get_sha1_hex(buf, sha1))
-				die("Bad sha1 on stdin: %s", buf);
-			llist_insert_sorted_unique(ignore, sha1, NULL);
+			oid = xmalloc(sizeof(*oid));
+			if (get_oid_hex(buf, oid))
+				die("Bad object ID on stdin: %s", buf);
+			llist_insert_sorted_unique(ignore, oid, NULL);
 		}
 	}
 	llist_sorted_difference_inplace(all_objects, ignore);

[PATCH v2 18/42] index-pack: abstract away hash function constant

[brian m. carlson]

The code for reading certain pack v2 offsets had a hard-coded 5
representing the number of uint32_t words that we needed to skip over.
Specify this value in terms of a value from the_hash_algo.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/index-pack.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 78e66b9986..9d6d19525a 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -1543,12 +1543,13 @@ static void read_v2_anomalous_offsets(struct packed_git *p,
 {
 	const uint32_t *idx1, *idx2;
 	uint32_t i;
+	const uint32_t hashwords = the_hash_algo->rawsz / sizeof(uint32_t);
 
 	/* The address of the 4-byte offset table */
 	idx1 = (((const uint32_t *)p->index_data)
 		+ 2 /* 8-byte header */
 		+ 256 /* fan out */
-		+ 5 * p->num_objects /* 20-byte SHA-1 table */
+		+ hashwords * p->num_objects /* object ID table */
 		+ p->num_objects /* CRC32 table */
 		);
 

[PATCH v2 19/42] commit: convert uses of get_sha1_hex to get_oid_hex

[brian m. carlson]

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 commit.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/commit.c b/commit.c
index ca474a7c11..9617f85caa 100644
--- a/commit.c
+++ b/commit.c
@@ -331,7 +331,7 @@ int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long s
 	if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 			bufptr[tree_entry_len] != '\n')
 		return error("bogus commit object %s", oid_to_hex(&item->object.oid));
-	if (get_sha1_hex(bufptr + 5, parent.hash) < 0)
+	if (get_oid_hex(bufptr + 5, &parent) < 0)
 		return error("bad tree pointer in commit %s",
 			     oid_to_hex(&item->object.oid));
 	item->tree = lookup_tree(&parent);
@@ -343,7 +343,7 @@ int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long s
 		struct commit *new_parent;
 
 		if (tail <= bufptr + parent_entry_len + 1 ||
-		    get_sha1_hex(bufptr + 7, parent.hash) ||
+		    get_oid_hex(bufptr + 7, &parent) ||
 		    bufptr[parent_entry_len] != '\n')
 			return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
 		bufptr += parent_entry_len + 1;

[PATCH v2 20/42] dir: convert struct untracked_cache_dir to object_id

[brian m. carlson]

Convert the exclude_sha1 member of struct untracked_cache_dir and rename
it to exclude_oid.  Eliminate several hard-coded integral constants, and
update a function name that referred to SHA-1.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 dir.c                                | 23 ++++++++++++-----------
 dir.h                                |  5 +++--
 t/helper/test-dump-untracked-cache.c |  2 +-
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/dir.c b/dir.c
index 63a917be45..06f4c4a8bf 100644
--- a/dir.c
+++ b/dir.c
@@ -1240,11 +1240,11 @@ static void prep_exclude(struct dir_struct *dir,
 		    (!untracked || !untracked->valid ||
 		     /*
 		      * .. and .gitignore does not exist before
-		      * (i.e. null exclude_sha1). Then we can skip
+		      * (i.e. null exclude_oid). Then we can skip
 		      * loading .gitignore, which would result in
 		      * ENOENT anyway.
 		      */
-		     !is_null_sha1(untracked->exclude_sha1))) {
+		     !is_null_oid(&untracked->exclude_oid))) {
 			/*
 			 * dir->basebuf gets reused by the traversal, but we
 			 * need fname to remain unchanged to ensure the src
@@ -1275,9 +1275,9 @@ static void prep_exclude(struct dir_struct *dir,
 		 * order, though, if you do that.
 		 */
 		if (untracked &&
-		    hashcmp(oid_stat.oid.hash, untracked->exclude_sha1)) {
+		    oidcmp(&oid_stat.oid, &untracked->exclude_oid)) {
 			invalidate_gitignore(dir->untracked, untracked);
-			hashcpy(untracked->exclude_sha1, oid_stat.oid.hash);
+			oidcpy(&untracked->exclude_oid, &oid_stat.oid);
 		}
 		dir->exclude_stack = stk;
 		current = stk->baselen;
@@ -2622,9 +2622,10 @@ static void write_one_dir(struct untracked_cache_dir *untracked,
 		stat_data_to_disk(&stat_data, &untracked->stat_data);
 		strbuf_add(&wd->sb_stat, &stat_data, sizeof(stat_data));
 	}
-	if (!is_null_sha1(untracked->exclude_sha1)) {
+	if (!is_null_oid(&untracked->exclude_oid)) {
 		ewah_set(wd->sha1_valid, i);
-		strbuf_add(&wd->sb_sha1, untracked->exclude_sha1, 20);
+		strbuf_add(&wd->sb_sha1, untracked->exclude_oid.hash,
+			   the_hash_algo->rawsz);
 	}
 
 	intlen = encode_varint(untracked->untracked_nr, intbuf);
@@ -2825,16 +2826,16 @@ static void read_stat(size_t pos, void *cb)
 	ud->valid = 1;
 }
 
-static void read_sha1(size_t pos, void *cb)
+static void read_oid(size_t pos, void *cb)
 {
 	struct read_data *rd = cb;
 	struct untracked_cache_dir *ud = rd->ucd[pos];
-	if (rd->data + 20 > rd->end) {
+	if (rd->data + the_hash_algo->rawsz > rd->end) {
 		rd->data = rd->end + 1;
 		return;
 	}
-	hashcpy(ud->exclude_sha1, rd->data);
-	rd->data += 20;
+	hashcpy(ud->exclude_oid.hash, rd->data);
+	rd->data += the_hash_algo->rawsz;
 }
 
 static void load_oid_stat(struct oid_stat *oid_stat, const unsigned char *data,
@@ -2917,7 +2918,7 @@ struct untracked_cache *read_untracked_extension(const void *data, unsigned long
 	ewah_each_bit(rd.check_only, set_check_only, &rd);
 	rd.data = next + len;
 	ewah_each_bit(rd.valid, read_stat, &rd);
-	ewah_each_bit(rd.sha1_valid, read_sha1, &rd);
+	ewah_each_bit(rd.sha1_valid, read_oid, &rd);
 	next = rd.data;
 
 done:
diff --git a/dir.h b/dir.h
index b0758b82a2..de66be9f4e 100644
--- a/dir.h
+++ b/dir.h
@@ -3,6 +3,7 @@
 
 /* See Documentation/technical/api-directory-listing.txt */
 
+#include "cache.h"
 #include "strbuf.h"
 
 struct dir_entry {
@@ -118,8 +119,8 @@ struct untracked_cache_dir {
 	/* all data except 'dirs' in this struct are good */
 	unsigned int valid : 1;
 	unsigned int recurse : 1;
-	/* null SHA-1 means this directory does not have .gitignore */
-	unsigned char exclude_sha1[20];
+	/* null object ID means this directory does not have .gitignore */
+	struct object_id exclude_oid;
 	char name[FLEX_ARRAY];
 };
 
diff --git a/t/helper/test-dump-untracked-cache.c b/t/helper/test-dump-untracked-cache.c
index d7c55c2355..bd92fb305a 100644
--- a/t/helper/test-dump-untracked-cache.c
+++ b/t/helper/test-dump-untracked-cache.c
@@ -23,7 +23,7 @@ static void dump(struct untracked_cache_dir *ucd, struct strbuf *base)
 	len = base->len;
 	strbuf_addf(base, "%s/", ucd->name);
 	printf("%s %s", base->buf,
-	       sha1_to_hex(ucd->exclude_sha1));
+	       oid_to_hex(&ucd->exclude_oid));
 	if (ucd->recurse)
 		fputs(" recurse", stdout);
 	if (ucd->check_only)

[PATCH v2 21/42] http: eliminate hard-coded constants

[brian m. carlson]

Use the_hash_algo to find the right size for parsing pack names.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 http.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/http.c b/http.c
index 3034d10b68..312a5e1833 100644
--- a/http.c
+++ b/http.c
@@ -2047,7 +2047,8 @@ int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
 	int ret = 0, i = 0;
 	char *url, *data;
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char sha1[20];
+	unsigned char hash[GIT_MAX_RAWSZ];
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	end_url_with_slash(&buf, base_url);
 	strbuf_addstr(&buf, "objects/info/packs");
@@ -2063,13 +2064,13 @@ int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
 		switch (data[i]) {
 		case 'P':
 			i++;
-			if (i + 52 <= buf.len &&
+			if (i + hexsz + 12 <= buf.len &&
 			    starts_with(data + i, " pack-") &&
-			    starts_with(data + i + 46, ".pack\n")) {
-				get_sha1_hex(data + i + 6, sha1);
-				fetch_and_setup_pack_index(packs_head, sha1,
+			    starts_with(data + i + hexsz + 6, ".pack\n")) {
+				get_sha1_hex(data + i + 6, hash);
+				fetch_and_setup_pack_index(packs_head, hash,
 						      base_url);
-				i += 51;
+				i += hexsz + 11;
 				break;
 			}
 		default:

[PATCH v2 22/42] revision: replace use of hard-coded constants

[brian m. carlson]

Replace two uses of the hard-coded constant 40 with references to
the_hash_algo.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 revision.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/revision.c b/revision.c
index ce0e7b71f2..daf7fe6ff4 100644
--- a/revision.c
+++ b/revision.c
@@ -1751,6 +1751,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	const char *arg = argv[0];
 	const char *optarg;
 	int argcount;
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	/* pseudo revision arguments */
 	if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
@@ -2038,8 +2039,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->abbrev = strtoul(optarg, NULL, 10);
 		if (revs->abbrev < MINIMUM_ABBREV)
 			revs->abbrev = MINIMUM_ABBREV;
-		else if (revs->abbrev > 40)
-			revs->abbrev = 40;
+		else if (revs->abbrev > hexsz)
+			revs->abbrev = hexsz;
 	} else if (!strcmp(arg, "--abbrev-commit")) {
 		revs->abbrev_commit = 1;
 		revs->abbrev_commit_given = 1;

[PATCH v2 23/42] upload-pack: replace use of several hard-coded constants

[brian m. carlson]

Update several uses of hard-coded 40-based constants to use either
the_hash_algo or GIT_MAX_HEXSZ, as appropriate.  Replace a combined use
of oid_to_hex and memcpy with oid_to_hex_r, which not only avoids the
need for a constant, but is more efficient.  Make use of parse_oid_hex
to eliminate the need for constants and simplify the code at the same
time.  Update some comments to no longer refer to SHA-1 as well.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 upload-pack.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/upload-pack.c b/upload-pack.c
index 6261d4fab3..e9adbe2f87 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -450,7 +450,7 @@ static int get_common_commits(void)
 				break;
 			default:
 				got_common = 1;
-				memcpy(last_hex, oid_to_hex(&oid), 41);
+				oid_to_hex_r(last_hex, &oid);
 				if (multi_ack == 2)
 					packet_write_fmt(1, "ACK %s common\n", last_hex);
 				else if (multi_ack)
@@ -492,7 +492,7 @@ static int do_reachable_revlist(struct child_process *cmd,
 		"rev-list", "--stdin", NULL,
 	};
 	struct object *o;
-	char namebuf[42]; /* ^ + SHA-1 + LF */
+	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
 	int i;
 
 	cmd->argv = argv;
@@ -561,15 +561,17 @@ static int get_reachable_list(struct object_array *src,
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	int i;
 	struct object *o;
-	char namebuf[42]; /* ^ + SHA-1 + LF */
+	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	if (do_reachable_revlist(&cmd, src, reachable) < 0)
 		return -1;
 
-	while ((i = read_in_full(cmd.out, namebuf, 41)) == 41) {
+	while ((i = read_in_full(cmd.out, namebuf, hexsz + 1)) == hexsz + 1) {
 		struct object_id sha1;
+		const char *p;
 
-		if (namebuf[40] != '\n' || get_oid_hex(namebuf, &sha1))
+		if (parse_oid_hex(namebuf, &sha1, &p) || *p != '\n')
 			break;
 
 		o = lookup_object(sha1.hash);
@@ -820,11 +822,9 @@ static void receive_needs(void)
 			continue;
 		}
 		if (!skip_prefix(line, "want ", &arg) ||
-		    get_oid_hex(arg, &oid_buf))
+		    parse_oid_hex(arg, &oid_buf, &features))
 			die("git upload-pack: protocol error, "
-			    "expected to get sha, not '%s'", line);
-
-		features = arg + 40;
+			    "expected to get object ID, not '%s'", line);
 
 		if (parse_feature_request(features, "deepen-relative"))
 			deepen_relative = 1;

[PATCH v2 24/42] diff: specify abbreviation size in terms of the_hash_algo

[brian m. carlson]

Instead of using hard-coded 40 constants, refer to the_hash_algo for the
current hash size.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 diff.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/diff.c b/diff.c
index 314c57e3c0..b1666b9b2d 100644
--- a/diff.c
+++ b/diff.c
@@ -3897,13 +3897,14 @@ static void fill_metainfo(struct strbuf *msg,
 		*must_show_header = 0;
 	}
 	if (one && two && oidcmp(&one->oid, &two->oid)) {
-		int abbrev = o->flags.full_index ? 40 : DEFAULT_ABBREV;
+		const unsigned hexsz = the_hash_algo->hexsz;
+		int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
 
 		if (o->flags.binary) {
 			mmfile_t mf;
 			if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
 			    (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
-				abbrev = 40;
+				abbrev = hexsz;
 		}
 		strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
 			    diff_abbrev_oid(&one->oid, abbrev),
@@ -4138,6 +4139,11 @@ void diff_setup_done(struct diff_options *options)
 			      DIFF_FORMAT_NAME_STATUS |
 			      DIFF_FORMAT_CHECKDIFF |
 			      DIFF_FORMAT_NO_OUTPUT;
+	/*
+	 * This must be signed because we're comparing against a potentially
+	 * negative value.
+	 */
+	const int hexsz = the_hash_algo->hexsz;
 
 	if (options->set_default)
 		options->set_default(options);
@@ -4218,8 +4224,8 @@ void diff_setup_done(struct diff_options *options)
 			 */
 			read_cache();
 	}
-	if (40 < options->abbrev)
-		options->abbrev = 40; /* full */
+	if (hexsz < options->abbrev)
+		options->abbrev = hexsz; /* full */
 
 	/*
 	 * It does not make sense to show the first hit we happened
@@ -4797,8 +4803,8 @@ int diff_opt_parse(struct diff_options *options,
 		options->abbrev = strtoul(arg, NULL, 10);
 		if (options->abbrev < MINIMUM_ABBREV)
 			options->abbrev = MINIMUM_ABBREV;
-		else if (40 < options->abbrev)
-			options->abbrev = 40;
+		else if (the_hash_algo->hexsz < options->abbrev)
+			options->abbrev = the_hash_algo->hexsz;
 	}
 	else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
 		options->a_prefix = optarg;

[PATCH v2 25/42] builtin/receive-pack: avoid hard-coded constants for push certs

[brian m. carlson]

Use the GIT_SHA1_RAWSZ and GIT_SHA1_HEXSZ macros instead of hard-coding
the constants 20 and 40.  Switch one use of 20 with a format specifier
for a hex value to use the hex constant instead, as the original appears
to have been a typo.

At this point, avoid converting the hard-coded use of SHA-1 to use
the_hash_algo.  SHA-1, even if not collision resistant, is secure in the
context in which it is used here, and the hash algorithm of the repo
need not match what is used here.  When we adopt a new hash algorithm,
we can simply adopt the new algorithm wholesale here, as the nonce is
opaque and its length and validity are entirely controlled by the
server.  Consequently, defer updating this code until that point.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/receive-pack.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 4b68a28e92..6501d6b6cf 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -454,21 +454,21 @@ static void hmac_sha1(unsigned char *out,
 	/* RFC 2104 2. (6) & (7) */
 	git_SHA1_Init(&ctx);
 	git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));
-	git_SHA1_Update(&ctx, out, 20);
+	git_SHA1_Update(&ctx, out, GIT_SHA1_RAWSZ);
 	git_SHA1_Final(out, &ctx);
 }
 
 static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
 {
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char sha1[20];
+	unsigned char sha1[GIT_SHA1_RAWSZ];
 
 	strbuf_addf(&buf, "%s:%"PRItime, path, stamp);
 	hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;
 	strbuf_release(&buf);
 
 	/* RFC 2104 5. HMAC-SHA1-80 */
-	strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1));
+	strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, GIT_SHA1_HEXSZ, sha1_to_hex(sha1));
 	return strbuf_detach(&buf, NULL);
 }
 

[PATCH v2 26/42] sha1-file: add functions for hex empty tree and blob OIDs

[brian m. carlson]

Oftentimes, we'll want to refer to an empty tree or empty blob by its
hex name without having to call oid_to_hex or explicitly refer to
the_hash_algo.  Add helper functions that format these values into
static buffers and return them for easy use.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h     |  3 +++
 sha1-file.c | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/cache.h b/cache.h
index 37d081b8e4..7115770fa6 100644
--- a/cache.h
+++ b/cache.h
@@ -1049,6 +1049,9 @@ static inline int is_empty_tree_oid(const struct object_id *oid)
 	return !oidcmp(oid, the_hash_algo->empty_tree);
 }
 
+const char *empty_tree_oid_hex(void);
+const char *empty_blob_oid_hex(void);
+
 /* set default permissions by passing mode arguments to open(2) */
 int git_mkstemps_mode(char *pattern, int suffix_len, int mode);
 int git_mkstemp_mode(char *pattern, int mode);
diff --git a/sha1-file.c b/sha1-file.c
index 4328c61285..11598b43eb 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -100,6 +100,18 @@ const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
 	},
 };
 
+const char *empty_tree_oid_hex(void)
+{
+	static char buf[GIT_MAX_HEXSZ + 1];
+	return oid_to_hex_r(buf, the_hash_algo->empty_tree);
+}
+
+const char *empty_blob_oid_hex(void)
+{
+	static char buf[GIT_MAX_HEXSZ + 1];
+	return oid_to_hex_r(buf, the_hash_algo->empty_blob);
+}
+
 /*
  * This is meant to hold a *small* number of objects that you would
  * want read_sha1_file() to be able to return, but yet you do not want

[PATCH v2 27/42] builtin/am: convert uses of EMPTY_TREE_SHA1_BIN to the_hash_algo

[brian m. carlson]

Convert several uses of EMPTY_TREE_SHA1_BIN to use the_hash_algo
and struct object_id instead.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/am.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index d834f9e62b..206af06a18 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1542,7 +1542,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 	char *their_tree_name;
 
 	if (get_oid("HEAD", &our_tree) < 0)
-		hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&our_tree, the_hash_algo->empty_tree);
 
 	if (build_fake_ancestor(state, index_path))
 		return error("could not build fake ancestor");
@@ -2042,7 +2042,7 @@ static void am_skip(struct am_state *state)
 	am_rerere_clear();
 
 	if (get_oid("HEAD", &head))
-		hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&head, the_hash_algo->empty_tree);
 
 	if (clean_index(&head, &head))
 		die(_("failed to clean index"));
@@ -2105,11 +2105,11 @@ static void am_abort(struct am_state *state)
 	curr_branch = resolve_refdup("HEAD", 0, &curr_head, NULL);
 	has_curr_head = curr_branch && !is_null_oid(&curr_head);
 	if (!has_curr_head)
-		hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&curr_head, the_hash_algo->empty_tree);
 
 	has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
 	if (!has_orig_head)
-		hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&orig_head, the_hash_algo->empty_tree);
 
 	clean_index(&curr_head, &orig_head);
 

[PATCH v2 28/42] builtin/merge: switch tree functions to use object_id

[brian m. carlson]

The read_empty and reset_hard functions are static and their callers
have already changed to use struct object_id, so convert them as well.
To avoid dependency on the hash algorithm in use, switch from using
EMPTY_TREE_SHA1_HEX to using empty_tree_oid_hex.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/merge.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/builtin/merge.c b/builtin/merge.c
index 9db5a2cf16..7084bcfdea 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -280,7 +280,7 @@ static int save_state(struct object_id *stash)
 	return rc;
 }
 
-static void read_empty(unsigned const char *sha1, int verbose)
+static void read_empty(const struct object_id *oid, int verbose)
 {
 	int i = 0;
 	const char *args[7];
@@ -290,15 +290,15 @@ static void read_empty(unsigned const char *sha1, int verbose)
 		args[i++] = "-v";
 	args[i++] = "-m";
 	args[i++] = "-u";
-	args[i++] = EMPTY_TREE_SHA1_HEX;
-	args[i++] = sha1_to_hex(sha1);
+	args[i++] = empty_tree_oid_hex();
+	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
 		die(_("read-tree failed"));
 }
 
-static void reset_hard(unsigned const char *sha1, int verbose)
+static void reset_hard(const struct object_id *oid, int verbose)
 {
 	int i = 0;
 	const char *args[6];
@@ -308,7 +308,7 @@ static void reset_hard(unsigned const char *sha1, int verbose)
 		args[i++] = "-v";
 	args[i++] = "--reset";
 	args[i++] = "-u";
-	args[i++] = sha1_to_hex(sha1);
+	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
@@ -324,7 +324,7 @@ static void restore_state(const struct object_id *head,
 	if (is_null_oid(stash))
 		return;
 
-	reset_hard(head->hash, 1);
+	reset_hard(head, 1);
 
 	args[2] = oid_to_hex(stash);
 
@@ -1297,7 +1297,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		if (remoteheads->next)
 			die(_("Can merge only exactly one commit into empty head"));
 		remote_head_oid = &remoteheads->item->object.oid;
-		read_empty(remote_head_oid->hash, 0);
+		read_empty(remote_head_oid, 0);
 		update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 		goto done;

[PATCH v2 29/42] merge: convert empty tree constant to the_hash_algo

[brian m. carlson]

To avoid dependency on a particular hash algorithm, convert a use of
EMPTY_TREE_SHA1_HEX to use the_hash_algo->empty_tree instead.  Since
both branches now use oid_to_hex, condense the if statement into a
ternary.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 merge.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/merge.c b/merge.c
index f06a4773d4..5186cb6156 100644
--- a/merge.c
+++ b/merge.c
@@ -11,10 +11,7 @@
 
 static const char *merge_argument(struct commit *commit)
 {
-	if (commit)
-		return oid_to_hex(&commit->object.oid);
-	else
-		return EMPTY_TREE_SHA1_HEX;
+	return oid_to_hex(commit ? &commit->object.oid : the_hash_algo->empty_tree);
 }
 
 int index_has_changes(struct strbuf *sb)

[PATCH v2 30/42] sequencer: convert one use of EMPTY_TREE_SHA1_HEX

[brian m. carlson]

Convert one use of EMPTY_TREE_SHA1_HEX to use empty_tree_oid_hex to
avoid a dependency on a given hash algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 sequencer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sequencer.c b/sequencer.c
index 5e3a50fafc..75ed9676fe 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1481,7 +1481,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		unborn = get_oid("HEAD", &head);
 		if (unborn)
 			oidcpy(&head, the_hash_algo->empty_tree);
-		if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD",
+		if (index_differs_from(unborn ? empty_tree_oid_hex() : "HEAD",
 				       NULL, 0))
 			return error_dirty_index(opts);
 	}

[PATCH v2 31/42] submodule: convert several uses of EMPTY_TREE_SHA1_HEX

[brian m. carlson]

Convert several uses of EMPTY_TREE_SHA1_HEX to use empty_tree_oid_hex to
avoid a dependency on a given hash algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 submodule.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/submodule.c b/submodule.c
index 9a50168b23..ee7eea4877 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1567,7 +1567,7 @@ static void submodule_reset_index(const char *path)
 				   get_super_prefix_or_empty(), path);
 	argv_array_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
 
-	argv_array_push(&cp.args, EMPTY_TREE_SHA1_HEX);
+	argv_array_push(&cp.args, empty_tree_oid_hex());
 
 	if (run_command(&cp))
 		die("could not reset submodule index");
@@ -1659,9 +1659,9 @@ int submodule_move_head(const char *path,
 		argv_array_push(&cp.args, "-m");
 
 	if (!(flags & SUBMODULE_MOVE_HEAD_FORCE))
-		argv_array_push(&cp.args, old_head ? old_head : EMPTY_TREE_SHA1_HEX);
+		argv_array_push(&cp.args, old_head ? old_head : empty_tree_oid_hex());
 
-	argv_array_push(&cp.args, new_head ? new_head : EMPTY_TREE_SHA1_HEX);
+	argv_array_push(&cp.args, new_head ? new_head : empty_tree_oid_hex());
 
 	if (run_command(&cp)) {
 		ret = -1;

[PATCH v2 32/42] wt-status: convert two uses of EMPTY_TREE_SHA1_HEX

[brian m. carlson]

Convert two uses of EMPTY_TREE_SHA1_HEX to use empty_tree_oid_hex to
avoid a dependency on a given hash algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 wt-status.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/wt-status.c b/wt-status.c
index 50815e5faf..e44115b3be 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -603,7 +603,7 @@ static void wt_status_collect_changes_index(struct wt_status *s)
 
 	init_revisions(&rev, NULL);
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? EMPTY_TREE_SHA1_HEX : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.flags.override_submodule_config = 1;
@@ -981,7 +981,7 @@ static void wt_longstatus_print_verbose(struct wt_status *s)
 	rev.diffopt.ita_invisible_in_index = 1;
 
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? EMPTY_TREE_SHA1_HEX : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;

[PATCH v2 33/42] builtin/receive-pack: convert one use of EMPTY_TREE_SHA1_HEX

[brian m. carlson]

Convert one use of EMPTY_TREE_SHA1_HEX to use empty_tree_oid_hex to
avoid a dependency on a given hash algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/receive-pack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 6501d6b6cf..b6b3bc1334 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -968,7 +968,7 @@ static const char *push_to_deploy(unsigned char *sha1,
 		return "Working directory has unstaged changes";
 
 	/* diff-index with either HEAD or an empty tree */
-	diff_index[4] = head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX;
+	diff_index[4] = head_has_history() ? "HEAD" : empty_tree_oid_hex();
 
 	child_process_init(&child);
 	child.argv = diff_index;

[PATCH v2 34/42] builtin/reset: convert use of EMPTY_TREE_SHA1_BIN

[brian m. carlson]

Convert the last use of EMPTY_TREE_SHA1_BIN to use a direct copy from
the_hash_algo->empty_tree to avoid a dependency on a given hash
algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 builtin/reset.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/builtin/reset.c b/builtin/reset.c
index 7f1c3f02a3..a862c70fab 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -314,7 +314,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	unborn = !strcmp(rev, "HEAD") && get_oid("HEAD", &oid);
 	if (unborn) {
 		/* reset on unborn branch: treat as reset to empty tree */
-		hashcpy(oid.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&oid, the_hash_algo->empty_tree);
 	} else if (!pathspec.nr) {
 		struct commit *commit;
 		if (get_oid_committish(rev, &oid))

[PATCH v2 35/42] sha1_file: convert cached object code to struct object_id

[brian m. carlson]

Convert the code that looks up cached objects to use struct object_id.
Adjust the lookup for empty trees to use the_hash_algo.  Note that we
don't need to be concerned about the hard-coded object ID in the
empty_tree object since we never use it.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 sha1-file.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/sha1-file.c b/sha1-file.c
index 11598b43eb..4acbf8ee08 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -119,7 +119,7 @@ const char *empty_blob_oid_hex(void)
  * application).
  */
 static struct cached_object {
-	unsigned char sha1[20];
+	struct object_id oid;
 	enum object_type type;
 	void *buf;
 	unsigned long size;
@@ -127,22 +127,22 @@ static struct cached_object {
 static int cached_object_nr, cached_object_alloc;
 
 static struct cached_object empty_tree = {
-	EMPTY_TREE_SHA1_BIN_LITERAL,
+	{ EMPTY_TREE_SHA1_BIN_LITERAL },
 	OBJ_TREE,
 	"",
 	0
 };
 
-static struct cached_object *find_cached_object(const unsigned char *sha1)
+static struct cached_object *find_cached_object(const struct object_id *oid)
 {
 	int i;
 	struct cached_object *co = cached_objects;
 
 	for (i = 0; i < cached_object_nr; i++, co++) {
-		if (!hashcmp(co->sha1, sha1))
+		if (!oidcmp(&co->oid, oid))
 			return co;
 	}
-	if (!hashcmp(sha1, empty_tree.sha1))
+	if (!oidcmp(oid, the_hash_algo->empty_tree))
 		return &empty_tree;
 	return NULL;
 }
@@ -1260,7 +1260,7 @@ int oid_object_info_extended(const struct object_id *oid, struct object_info *oi
 		oi = &blank_oi;
 
 	if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
-		struct cached_object *co = find_cached_object(real->hash);
+		struct cached_object *co = find_cached_object(real);
 		if (co) {
 			if (oi->typep)
 				*(oi->typep) = co->type;
@@ -1369,7 +1369,7 @@ int pretend_object_file(void *buf, unsigned long len, enum object_type type,
 	struct cached_object *co;
 
 	hash_object_file(buf, len, type_name(type), oid);
-	if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
+	if (has_sha1_file(oid->hash) || find_cached_object(oid))
 		return 0;
 	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
 	co = &cached_objects[cached_object_nr++];
@@ -1377,7 +1377,7 @@ int pretend_object_file(void *buf, unsigned long len, enum object_type type,
 	co->type = type;
 	co->buf = xmalloc(len);
 	memcpy(co->buf, buf, len);
-	hashcpy(co->sha1, oid->hash);
+	oidcpy(&co->oid, oid);
 	return 0;
 }
 

[PATCH v2 36/42] cache-tree: use is_empty_tree_oid

[brian m. carlson]

When comparing an object ID against that of the empty tree, use the
is_empty_tree_oid function to ensure that we abstract over the hash
algorithm properly.  In addition, this is more readable than a plain
oidcmp.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cache-tree.c b/cache-tree.c
index 8c7e1258a4..25663825b5 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -385,7 +385,7 @@ static int update_one(struct cache_tree *it,
 		/*
 		 * "sub" can be an empty tree if all subentries are i-t-a.
 		 */
-		if (contains_ita && !oidcmp(oid, &empty_tree_oid))
+		if (contains_ita && is_empty_tree_oid(oid))
 			continue;
 
 		strbuf_grow(&buffer, entlen + 100);

[PATCH v2 37/42] sequencer: use the_hash_algo for empty tree object ID

[brian m. carlson]

To ensure that we are hash algorithm agnostic, use the_hash_algo to look
up the object ID for the empty tree instead of using the empty_tree_oid
variable.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 sequencer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sequencer.c b/sequencer.c
index 75ed9676fe..a487411fde 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1120,7 +1120,7 @@ static int try_to_commit(struct strbuf *msg, const char *author,
 
 	if (!(flags & ALLOW_EMPTY) && !oidcmp(current_head ?
 					      &current_head->tree->object.oid :
-					      &empty_tree_oid, &tree)) {
+					      the_hash_algo->empty_tree, &tree)) {
 		res = 1; /* run 'git commit' to display error message */
 		goto out;
 	}

[PATCH v2 38/42] dir: use the_hash_algo for empty blob object ID

[brian m. carlson]

To ensure that we are hash algorithm agnostic, use the_hash_algo to look
up the object ID for the empty blob instead of using the empty_tree_oid
variable.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 dir.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dir.c b/dir.c
index 06f4c4a8bf..e879c34c2e 100644
--- a/dir.c
+++ b/dir.c
@@ -828,7 +828,7 @@ static int add_excludes(const char *fname, const char *base, int baselen,
 		if (size == 0) {
 			if (oid_stat) {
 				fill_stat_data(&oid_stat->stat, &st);
-				oidcpy(&oid_stat->oid, &empty_blob_oid);
+				oidcpy(&oid_stat->oid, the_hash_algo->empty_blob);
 				oid_stat->valid = 1;
 			}
 			close(fd);

[PATCH v2 39/42] sha1_file: only expose empty object constants through git_hash_algo

[brian m. carlson]

There really isn't any case in which we want to expose the constants for
empty trees and blobs outside of using the hash algorithm abstraction.
Make these constants static and stop exposing the defines in cache.h.
Remove the constants which are no longer in use.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 cache.h     | 16 ----------------
 sha1-file.c | 13 +++++++++++--
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/cache.h b/cache.h
index 7115770fa6..ffe145c539 100644
--- a/cache.h
+++ b/cache.h
@@ -1013,22 +1013,6 @@ static inline void oidread(struct object_id *oid, const unsigned char *hash)
 	memcpy(oid->hash, hash, the_hash_algo->rawsz);
 }
 
-
-#define EMPTY_TREE_SHA1_HEX \
-	"4b825dc642cb6eb9a060e54bf8d69288fbee4904"
-#define EMPTY_TREE_SHA1_BIN_LITERAL \
-	 "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
-	 "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
-extern const struct object_id empty_tree_oid;
-#define EMPTY_TREE_SHA1_BIN (empty_tree_oid.hash)
-
-#define EMPTY_BLOB_SHA1_HEX \
-	"e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
-#define EMPTY_BLOB_SHA1_BIN_LITERAL \
-	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
-	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
-extern const struct object_id empty_blob_oid;
-
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {
 	return !hashcmp(sha1, the_hash_algo->empty_blob->hash);
diff --git a/sha1-file.c b/sha1-file.c
index 4acbf8ee08..bf6c8da3ff 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -35,12 +35,21 @@
 /* The maximum size for an object header. */
 #define MAX_HEADER_LEN 32
 
+
+#define EMPTY_TREE_SHA1_BIN_LITERAL \
+	 "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
+	 "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
+
+#define EMPTY_BLOB_SHA1_BIN_LITERAL \
+	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
+	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
+
 const unsigned char null_sha1[GIT_MAX_RAWSZ];
 const struct object_id null_oid;
-const struct object_id empty_tree_oid = {
+static const struct object_id empty_tree_oid = {
 	EMPTY_TREE_SHA1_BIN_LITERAL
 };
-const struct object_id empty_blob_oid = {
+static const struct object_id empty_blob_oid = {
 	EMPTY_BLOB_SHA1_BIN_LITERAL
 };
 

[PATCH v2 40/42] Update shell scripts to compute empty tree object ID

[brian m. carlson]

Several of our shell scripts hard-code the object ID of the empty tree.
To avoid any problems when changing hashes, compute this value on
startup of the script.  For performance, store the value in a variable
and reuse it throughout the life of the script.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 git-filter-branch.sh               | 4 +++-
 git-rebase--interactive.sh         | 4 +++-
 templates/hooks--pre-commit.sample | 2 +-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 64f21547c1..ccceaf19a7 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -11,6 +11,8 @@
 # The following functions will also be available in the commit filter:
 
 functions=$(cat << \EOF
+EMPTY_TREE=$(git hash-object -t tree /dev/null)
+
 warn () {
 	echo "$*" >&2
 }
@@ -46,7 +48,7 @@ git_commit_non_empty_tree()
 {
 	if test $# = 3 && test "$1" = $(git rev-parse "$3^{tree}"); then
 		map "$3"
-	elif test $# = 1 && test "$1" = 4b825dc642cb6eb9a060e54bf8d69288fbee4904; then
+	elif test $# = 1 && test "$1" = $EMPTY_TREE; then
 		:
 	else
 		git commit-tree "$@"
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index 9947e6265f..e5ae58a07e 100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -81,6 +81,8 @@ rewritten_pending="$state_dir"/rewritten-pending
 # and leaves CR at the end instead.
 cr=$(printf "\015")
 
+empty_tree=$(git hash-object -t tree /dev/null)
+
 strategy_args=${strategy:+--strategy=$strategy}
 test -n "$strategy_opts" &&
 eval '
@@ -238,7 +240,7 @@ is_empty_commit() {
 		die "$(eval_gettext "\$sha1: not a commit that can be picked")"
 	}
 	ptree=$(git rev-parse -q --verify "$1"^^{tree} 2>/dev/null) ||
-		ptree=4b825dc642cb6eb9a060e54bf8d69288fbee4904
+		ptree=$empty_tree
 	test "$tree" = "$ptree"
 }
 
diff --git a/templates/hooks--pre-commit.sample b/templates/hooks--pre-commit.sample
index 68d62d5446..6a75641638 100755
--- a/templates/hooks--pre-commit.sample
+++ b/templates/hooks--pre-commit.sample
@@ -12,7 +12,7 @@ then
 	against=HEAD
 else
 	# Initial commit: diff against an empty tree object
-	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
+	against=$(git hash-object -t tree /dev/null)
 fi
 
 # If you want to allow non-ASCII filenames set this variable to true.

[PATCH v2 41/42] add--interactive: compute the empty tree value

[brian m. carlson]

The interactive add script hard-codes the object ID of the empty tree.
To avoid any problems when changing hashes, compute this value when used
and cache it for any future uses.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 git-add--interactive.perl | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index c1f52e457f..36f38ced90 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -205,8 +205,15 @@ my $status_head = sprintf($status_fmt, __('staged'), __('unstaged'), __('path'))
 	}
 }
 
-sub get_empty_tree {
-	return '4b825dc642cb6eb9a060e54bf8d69288fbee4904';
+{
+	my $empty_tree;
+	sub get_empty_tree {
+		return $empty_tree if defined $empty_tree;
+
+		$empty_tree = run_cmd_pipe(qw(git hash-object -t tree /dev/null));
+		chomp $empty_tree;
+		return $empty_tree;
+	}
 }
 
 sub get_diff_reference {

[PATCH v2 42/42] merge-one-file: compute empty blob object ID

[brian m. carlson]

This script hard-codes the object ID of the empty blob.  To avoid any
problems when changing hashes, compute this value by calling git
hash-object.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 git-merge-one-file.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/git-merge-one-file.sh b/git-merge-one-file.sh
index 9879c59395..f6d9852d2f 100755
--- a/git-merge-one-file.sh
+++ b/git-merge-one-file.sh
@@ -120,7 +120,7 @@ case "${1:-.}${2:-.}${3:-.}" in
 	case "$1" in
 	'')
 		echo "Added $4 in both, but differently."
-		orig=$(git unpack-file e69de29bb2d1d6434b8b29ae775ad8c2e48c5391)
+		orig=$(git unpack-file $(git hash-object /dev/null))
 		;;
 	*)
 		echo "Auto-merging $4"

Re: [PATCH v2 00/42] object_id part 13

[Duy Nguyen]

On Wed, May 02, 2018 at 12:25:28AM +0000, brian m. carlson wrote:
> Changes from v1:
> * Add missing sign-off.
> * Removed unneeded braces from init_pack_info.
> * Express 51 in terms of the_hash_algo->hexsz.
> * Fix comments referring to SHA-1.
> * Update commit messages as suggested.
> * Add and use empty_tree_oid_hex and empty_blob_oid_hex.

Interdiff for people who don't have time to read 42 patches yet

diff --git a/builtin/merge.c b/builtin/merge.c
index 8d75ebe64b..7084bcfdea 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -290,7 +290,7 @@ static void read_empty(const struct object_id *oid, int verbose)
 		args[i++] = "-v";
 	args[i++] = "-m";
 	args[i++] = "-u";
-	args[i++] = oid_to_hex(the_hash_algo->empty_tree);
+	args[i++] = empty_tree_oid_hex();
 	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index c31ceb30c2..dca523f50f 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -968,7 +968,7 @@ static const char *push_to_deploy(unsigned char *sha1,
 		return "Working directory has unstaged changes";
 
 	/* diff-index with either HEAD or an empty tree */
-	diff_index[4] = head_has_history() ? "HEAD" : oid_to_hex(the_hash_algo->empty_tree);
+	diff_index[4] = head_has_history() ? "HEAD" : empty_tree_oid_hex();
 
 	child_process_init(&child);
 	child.argv = diff_index;
diff --git a/cache.h b/cache.h
index c5b041019b..71b3c1b15b 100644
--- a/cache.h
+++ b/cache.h
@@ -1033,6 +1033,9 @@ static inline int is_empty_tree_oid(const struct object_id *oid)
 	return !oidcmp(oid, the_hash_algo->empty_tree);
 }
 
+const char *empty_tree_oid_hex(void);
+const char *empty_blob_oid_hex(void);
+
 /* set default permissions by passing mode arguments to open(2) */
 int git_mkstemps_mode(char *pattern, int suffix_len, int mode);
 int git_mkstemp_mode(char *pattern, int mode);
diff --git a/http.c b/http.c
index ec70676748..312a5e1833 100644
--- a/http.c
+++ b/http.c
@@ -2070,7 +2070,7 @@ int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
 				get_sha1_hex(data + i + 6, hash);
 				fetch_and_setup_pack_index(packs_head, hash,
 						      base_url);
-				i += 51;
+				i += hexsz + 11;
 				break;
 			}
 		default:
diff --git a/sequencer.c b/sequencer.c
index 12c1e1cdbb..94b6513402 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1480,8 +1480,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		unborn = get_oid("HEAD", &head);
 		if (unborn)
 			oidcpy(&head, the_hash_algo->empty_tree);
-		if (index_differs_from(unborn ?
-				       oid_to_hex(the_hash_algo->empty_tree) : "HEAD",
+		if (index_differs_from(unborn ? empty_tree_oid_hex() : "HEAD",
 				       NULL, 0))
 			return error_dirty_index(opts);
 	}
diff --git a/server-info.c b/server-info.c
index 828ec5e538..7ce6dcd67b 100644
--- a/server-info.c
+++ b/server-info.c
@@ -223,11 +223,9 @@ static void init_pack_info(const char *infofile, int force)
 	else
 		stale = 1;
 
-	for (i = 0; i < num_pack; i++) {
-		if (stale) {
+	for (i = 0; i < num_pack; i++)
+		if (stale)
 			info[i]->old_num = -1;
-		}
-	}
 
 	/* renumber them */
 	QSORT(info, num_pack, compare_info);
diff --git a/sha1_file.c b/sha1_file.c
index 794753bd54..bf6c8da3ff 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -109,6 +109,18 @@ const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
 	},
 };
 
+const char *empty_tree_oid_hex(void)
+{
+	static char buf[GIT_MAX_HEXSZ + 1];
+	return oid_to_hex_r(buf, the_hash_algo->empty_tree);
+}
+
+const char *empty_blob_oid_hex(void)
+{
+	static char buf[GIT_MAX_HEXSZ + 1];
+	return oid_to_hex_r(buf, the_hash_algo->empty_blob);
+}
+
 /*
  * This is meant to hold a *small* number of objects that you would
  * want read_sha1_file() to be able to return, but yet you do not want
diff --git a/submodule.c b/submodule.c
index 22a96b7af0..ee7eea4877 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1567,7 +1567,7 @@ static void submodule_reset_index(const char *path)
 				   get_super_prefix_or_empty(), path);
 	argv_array_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
 
-	argv_array_push(&cp.args, oid_to_hex(the_hash_algo->empty_tree));
+	argv_array_push(&cp.args, empty_tree_oid_hex());
 
 	if (run_command(&cp))
 		die("could not reset submodule index");
@@ -1659,9 +1659,9 @@ int submodule_move_head(const char *path,
 		argv_array_push(&cp.args, "-m");
 
 	if (!(flags & SUBMODULE_MOVE_HEAD_FORCE))
-		argv_array_push(&cp.args, old_head ? old_head : oid_to_hex(the_hash_algo->empty_tree));
+		argv_array_push(&cp.args, old_head ? old_head : empty_tree_oid_hex());
 
-	argv_array_push(&cp.args, new_head ? new_head : oid_to_hex(the_hash_algo->empty_tree));
+	argv_array_push(&cp.args, new_head ? new_head : empty_tree_oid_hex());
 
 	if (run_command(&cp)) {
 		ret = -1;
diff --git a/upload-pack.c b/upload-pack.c
index 0858527c5b..1fb4942235 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -492,7 +492,7 @@ static int do_reachable_revlist(struct child_process *cmd,
 		"rev-list", "--stdin", NULL,
 	};
 	struct object *o;
-	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + SHA-1 + LF */
+	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
 	int i;
 
 	cmd->argv = argv;
@@ -561,7 +561,7 @@ static int get_reachable_list(struct object_array *src,
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	int i;
 	struct object *o;
-	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + SHA-1 + LF */
+	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
 	const unsigned hexsz = the_hash_algo->hexsz;
 
 	if (do_reachable_revlist(&cmd, src, reachable) < 0)
diff --git a/wt-status.c b/wt-status.c
index 857724bd60..e44115b3be 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -600,11 +600,10 @@ static void wt_status_collect_changes_index(struct wt_status *s)
 {
 	struct rev_info rev;
 	struct setup_revision_opt opt;
-	char hex[GIT_MAX_HEXSZ + 1];
 
 	init_revisions(&rev, NULL);
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? oid_to_hex_r(hex, the_hash_algo->empty_tree) : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.flags.override_submodule_config = 1;
@@ -976,14 +975,13 @@ static void wt_longstatus_print_verbose(struct wt_status *s)
 	struct setup_revision_opt opt;
 	int dirty_submodules;
 	const char *c = color(WT_STATUS_HEADER, s);
-	char hex[GIT_MAX_HEXSZ + 1];
 
 	init_revisions(&rev, NULL);
 	rev.diffopt.flags.allow_textconv = 1;
 	rev.diffopt.ita_invisible_in_index = 1;
 
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? oid_to_hex_r(hex, the_hash_algo->empty_tree) : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;


--
Duy

Re: [PATCH v2 00/42] object_id part 13

[brian m. carlson]

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On Wed, May 02, 2018 at 05:32:24PM +0200, Duy Nguyen wrote:
> Interdiff for people who don't have time to read 42 patches yet

Thanks for this.  I had intended to include tbdiff output in my series
but had forgotten when I reformatted the patches.
-- 
brian m. carlson: Houston, Texas, US
OpenPGP: https://keybase.io/bk2204

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