[PATCH v2 00/15] Hash function transition part 15

[PATCH v2 00/15] Hash function transition part 15

[brian m. carlson]

This is the fifteenth series in the ongoing hash function transition.

This series includes several conversions to use the_hash_algo, combined
with some use of parse_oid_hex and GIT_MAX_RAWSZ.

Changes from v1:
* Fix several other substantially similar issues in builtin/repack.
* Fix a comment style issue.
* Improve commit message as suggested by Stefan.
* Pull in Gábor's patch and place it at the beginning of the series.

SZEDER Gábor (1):
  object_id.cocci: match only expressions of type 'struct object_id'

brian m. carlson (14):
  pack-bitmap-write: use GIT_MAX_RAWSZ for allocation
  builtin/repack: replace hard-coded constants
  builtin/mktree: remove hard-coded constant
  builtin/fetch-pack: remove constants with parse_oid_hex
  pack-revindex: express constants in terms of the_hash_algo
  packfile: express constants in terms of the_hash_algo
  refs/packed-backend: express constants using the_hash_algo
  upload-pack: express constants in terms of the_hash_algo
  transport: use parse_oid_hex instead of a constant
  tag: express constant in terms of the_hash_algo
  apply: replace hard-coded constants
  apply: rename new_sha1_prefix and old_sha1_prefix
  submodule: make zero-oid comparison hash function agnostic
  rerere: convert to use the_hash_algo

 apply.c                            |  50 ++++++------
 builtin/fetch-pack.c               |  13 ++--
 builtin/mktree.c                   |   2 +-
 builtin/repack.c                   |  13 ++--
 contrib/coccinelle/object_id.cocci | 117 ++++++++++++++++-------------
 git-submodule.sh                   |   7 +-
 pack-bitmap-write.c                |   2 +-
 pack-revindex.c                    |  10 ++-
 packfile.c                         |   5 +-
 refs/packed-backend.c              |  14 ++--
 rerere.c                           |  81 ++++++++++----------
 tag.c                              |   2 +-
 transport.c                        |   7 +-
 upload-pack.c                      |  13 ++--
 14 files changed, 181 insertions(+), 155 deletions(-)

Range-diff against v1:
 -:  ---------- >  1:  35d9cefd9a object_id.cocci: match only expressions of type 'struct object_id'
 1:  223d6f6695 !  2:  bb2a15a6e9 pack-bitmap-write: use GIT_MAX_RAWSZ for allocation
    @@ -2,6 +2,7 @@
     
         pack-bitmap-write: use GIT_MAX_RAWSZ for allocation
     
    +    Reviewed-by: Stefan Beller <sbeller@google.com>
         Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
     
      diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
 2:  bbdb147d8d <  -:  ---------- builtin/repack: replace hard-coded constant
 -:  ---------- >  3:  95bdac161e builtin/repack: replace hard-coded constants
 3:  bf7b55fe4e =  4:  2a28675cfc builtin/mktree: remove hard-coded constant
 4:  155451f608 =  5:  7941bb0060 builtin/fetch-pack: remove constants with parse_oid_hex
 5:  9ec7065d62 !  6:  2ec9a22ea7 pack-revindex: express constants in terms of the_hash_algo
    @@ -3,7 +3,9 @@
         pack-revindex: express constants in terms of the_hash_algo
     
         Express the various constants used in terms of the_hash_algo.
    +    While we're at it, fix a comment style issue as well.
     
    +    Reviewed-by: Stefan Beller <sbeller@google.com>
         Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
     
      diff --git a/pack-revindex.c b/pack-revindex.c
    @@ -37,7 +39,8 @@
      	}
      
     -	/* This knows the pack format -- the 20-byte trailer
    -+	/* This knows the pack format -- the hash trailer
    ++	/*
    ++	 * This knows the pack format -- the hash trailer
      	 * follows immediately after the last object data.
      	 */
     -	p->revindex[num_ent].offset = p->pack_size - 20;
 6:  5e8576c6e4 !  7:  3ccb2b7217 packfile: express constants in terms of the_hash_algo
    @@ -5,6 +5,11 @@
         Replace uses of GIT_SHA1_RAWSZ with references to the_hash_algo to avoid
         dependence on a particular hash length.
     
    +    It's likely that in the future, we'll update the pack format to indicate
    +    what hash algorithm it uses, and then this code will change.  However,
    +    at least on an interim basis, make it easier to develop on a pure
    +    SHA-256 Git by using the_hash_algo here.
    +
         Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
     
      diff --git a/packfile.c b/packfile.c
 7:  4c7b6471db =  8:  39eb7e1069 refs/packed-backend: express constants using the_hash_algo
 8:  8318dcb630 =  9:  55269d5fc2 upload-pack: express constants in terms of the_hash_algo
 9:  16916c9fa2 = 10:  d30536a3bd transport: use parse_oid_hex instead of a constant
10:  9d8e2bc4ae = 11:  2139fe1fe1 tag: express constant in terms of the_hash_algo
11:  58f91f2167 = 12:  af815c4215 apply: replace hard-coded constants
12:  6899dfc4af = 13:  f651b226c8 apply: rename new_sha1_prefix and old_sha1_prefix
13:  cc974651cb = 14:  bf1d450aa5 submodule: make zero-oid comparison hash function agnostic
14:  b373f16c12 = 15:  d984036c1c rerere: convert to use the_hash_algo

[PATCH v2 01/15] object_id.cocci: match only expressions of type 'struct object_id'

[brian m. carlson]

From: SZEDER Gábor <szeder.dev@gmail.com>

Most of our semantic patches in 'contrib/coccinelle/object_id.cocci'
turn calls of SHA1-specific functions into calls of their
corresponding object_id counterparts, e.g. sha1_to_hex() to
oid_to_hex().  These semantic patches look something like this:

  @@
  expression E1;
  @@
  - sha1_to_hex(E1.hash)
  + oid_to_hex(&E1)

and match the access to the 'hash' field in any data type, not only in
'struct object_id', and, consquently, can produce wrong
transformations.

Case in point is the recent hash function transition patch "rerere:
convert to use the_hash_algo" [1], which, among other things, renamed
'struct rerere_dir's 'sha1' field to 'hash', and then 'make
coccicheck' started to suggest the following wrong transformations for
'rerere.c' [2]:

  -    return sha1_to_hex(id->collection->hash);
  +    return oid_to_hex(id->collection);

and

  -    DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->hash)));
  +    DIR *dir = opendir(git_path("rr-cache/%s", oid_to_hex(rr_dir)));

Avoid such wrong transformations by tightening semantic patches in
'object_id.cocci' to match only type of or pointers to 'struct
object_id'.

[1] https://public-inbox.org/git/20181008215701.779099-15-sandals@crustytoothpaste.net/
[2] https://travis-ci.org/git/git/jobs/440463476#L580

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 contrib/coccinelle/object_id.cocci | 117 ++++++++++++++++-------------
 1 file changed, 63 insertions(+), 54 deletions(-)

diff --git a/contrib/coccinelle/object_id.cocci b/contrib/coccinelle/object_id.cocci
index d8bdb48712..6a7cf3e02d 100644
--- a/contrib/coccinelle/object_id.cocci
+++ b/contrib/coccinelle/object_id.cocci
@@ -1,119 +1,127 @@
 @@
-expression E1;
+struct object_id OID;
 @@
-- is_null_sha1(E1.hash)
-+ is_null_oid(&E1)
+- is_null_sha1(OID.hash)
++ is_null_oid(&OID)
 
 @@
-expression E1;
+struct object_id *OIDPTR;
 @@
-- is_null_sha1(E1->hash)
-+ is_null_oid(E1)
+- is_null_sha1(OIDPTR->hash)
++ is_null_oid(OIDPTR)
 
 @@
-expression E1;
+struct object_id OID;
 @@
-- sha1_to_hex(E1.hash)
-+ oid_to_hex(&E1)
+- sha1_to_hex(OID.hash)
++ oid_to_hex(&OID)
 
 @@
 identifier f != oid_to_hex;
-expression E1;
+struct object_id *OIDPTR;
 @@
   f(...) {<...
-- sha1_to_hex(E1->hash)
-+ oid_to_hex(E1)
+- sha1_to_hex(OIDPTR->hash)
++ oid_to_hex(OIDPTR)
   ...>}
 
 @@
-expression E1, E2;
+expression E;
+struct object_id OID;
 @@
-- sha1_to_hex_r(E1, E2.hash)
-+ oid_to_hex_r(E1, &E2)
+- sha1_to_hex_r(E, OID.hash)
++ oid_to_hex_r(E, &OID)
 
 @@
 identifier f != oid_to_hex_r;
-expression E1, E2;
+expression E;
+struct object_id *OIDPTR;
 @@
    f(...) {<...
-- sha1_to_hex_r(E1, E2->hash)
-+ oid_to_hex_r(E1, E2)
+- sha1_to_hex_r(E, OIDPTR->hash)
++ oid_to_hex_r(E, OIDPTR)
   ...>}
 
 @@
-expression E1;
+struct object_id OID;
 @@
-- hashclr(E1.hash)
-+ oidclr(&E1)
+- hashclr(OID.hash)
++ oidclr(&OID)
 
 @@
 identifier f != oidclr;
-expression E1;
+struct object_id *OIDPTR;
 @@
   f(...) {<...
-- hashclr(E1->hash)
-+ oidclr(E1)
+- hashclr(OIDPTR->hash)
++ oidclr(OIDPTR)
   ...>}
 
 @@
-expression E1, E2;
+struct object_id OID1, OID2;
 @@
-- hashcmp(E1.hash, E2.hash)
-+ oidcmp(&E1, &E2)
+- hashcmp(OID1.hash, OID2.hash)
++ oidcmp(&OID1, &OID2)
 
 @@
 identifier f != oidcmp;
-expression E1, E2;
+struct object_id *OIDPTR1, OIDPTR2;
 @@
   f(...) {<...
-- hashcmp(E1->hash, E2->hash)
-+ oidcmp(E1, E2)
+- hashcmp(OIDPTR1->hash, OIDPTR2->hash)
++ oidcmp(OIDPTR1, OIDPTR2)
   ...>}
 
 @@
-expression E1, E2;
+struct object_id *OIDPTR;
+struct object_id OID;
 @@
-- hashcmp(E1->hash, E2.hash)
-+ oidcmp(E1, &E2)
+- hashcmp(OIDPTR->hash, OID.hash)
++ oidcmp(OIDPTR, &OID)
 
 @@
-expression E1, E2;
+struct object_id *OIDPTR;
+struct object_id OID;
 @@
-- hashcmp(E1.hash, E2->hash)
-+ oidcmp(&E1, E2)
+- hashcmp(OID.hash, OIDPTR->hash)
++ oidcmp(&OID, OIDPTR)
 
 @@
-expression E1, E2;
+struct object_id OID1, OID2;
 @@
-- hashcpy(E1.hash, E2.hash)
-+ oidcpy(&E1, &E2)
+- hashcpy(OID1.hash, OID2.hash)
++ oidcpy(&OID1, &OID2)
 
 @@
 identifier f != oidcpy;
-expression E1, E2;
+struct object_id *OIDPTR1;
+struct object_id *OIDPTR2;
 @@
   f(...) {<...
-- hashcpy(E1->hash, E2->hash)
-+ oidcpy(E1, E2)
+- hashcpy(OIDPTR1->hash, OIDPTR2->hash)
++ oidcpy(OIDPTR1, OIDPTR2)
   ...>}
 
 @@
-expression E1, E2;
+struct object_id *OIDPTR;
+struct object_id OID;
 @@
-- hashcpy(E1->hash, E2.hash)
-+ oidcpy(E1, &E2)
+- hashcpy(OIDPTR->hash, OID.hash)
++ oidcpy(OIDPTR, &OID)
 
 @@
-expression E1, E2;
+struct object_id *OIDPTR;
+struct object_id OID;
 @@
-- hashcpy(E1.hash, E2->hash)
-+ oidcpy(&E1, E2)
+- hashcpy(OID.hash, OIDPTR->hash)
++ oidcpy(&OID, OIDPTR)
 
 @@
-expression E1, E2;
+struct object_id *OIDPTR1;
+struct object_id *OIDPTR2;
 @@
-- oidcmp(E1, E2) == 0
-+ oideq(E1, E2)
+- oidcmp(OIDPTR1, OIDPTR2) == 0
++ oideq(OIDPTR1, OIDPTR2)
 
 @@
 identifier f != hasheq;
@@ -125,10 +133,11 @@ expression E1, E2;
   ...>}
 
 @@
-expression E1, E2;
+struct object_id *OIDPTR1;
+struct object_id *OIDPTR2;
 @@
-- oidcmp(E1, E2) != 0
-+ !oideq(E1, E2)
+- oidcmp(OIDPTR1, OIDPTR2) != 0
++ !oideq(OIDPTR1, OIDPTR2)
 
 @@
 identifier f != hasheq;

[PATCH v2 02/15] pack-bitmap-write: use GIT_MAX_RAWSZ for allocation

[brian m. carlson]

Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 pack-bitmap-write.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index fc82f37a02..6f0c78d6aa 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -37,7 +37,7 @@ struct bitmap_writer {
 
 	struct progress *progress;
 	int show_progress;
-	unsigned char pack_checksum[20];
+	unsigned char pack_checksum[GIT_MAX_RAWSZ];
 };
 
 static struct bitmap_writer writer;

[PATCH v2 03/15] builtin/repack: replace hard-coded constants

[brian m. carlson]

Note that while the error messages here are not translated, the end user
should never see them.  We invoke git pack-objects shortly before both
invocations, so we can be fairly certain that the data we're receiving
is in fact valid.

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

diff --git a/builtin/repack.c b/builtin/repack.c
index c6a7943d5c..0223f2880c 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -235,8 +235,8 @@ static void repack_promisor_objects(const struct pack_objects_args *args,
 	while (strbuf_getline_lf(&line, out) != EOF) {
 		char *promisor_name;
 		int fd;
-		if (line.len != 40)
-			die("repack: Expecting 40 character sha1 lines only from pack-objects.");
+		if (line.len != the_hash_algo->hexsz)
+			die("repack: Expecting full hex object ID lines only from pack-objects.");
 		string_list_append(names, line.buf);
 
 		/*
@@ -407,8 +407,8 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 
 	out = xfdopen(cmd.out, "r");
 	while (strbuf_getline_lf(&line, out) != EOF) {
-		if (line.len != 40)
-			die("repack: Expecting 40 character sha1 lines only from pack-objects.");
+		if (line.len != the_hash_algo->hexsz)
+			die("repack: Expecting full hex object ID lines only from pack-objects.");
 		string_list_append(&names, line.buf);
 	}
 	fclose(out);
@@ -535,14 +535,15 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	reprepare_packed_git(the_repository);
 
 	if (delete_redundant) {
+		const int hexsz = the_hash_algo->hexsz;
 		int opts = 0;
 		string_list_sort(&names);
 		for_each_string_list_item(item, &existing_packs) {
 			char *sha1;
 			size_t len = strlen(item->string);
-			if (len < 40)
+			if (len < hexsz)
 				continue;
-			sha1 = item->string + len - 40;
+			sha1 = item->string + len - hexsz;
 			if (!string_list_has_string(&names, sha1))
 				remove_redundant_pack(packdir, item->string);
 		}

[PATCH v2 04/15] builtin/mktree: remove hard-coded constant

[brian m. carlson]

Instead of using a hard-coded constant for the size of a hex object ID,
switch to use the computed pointer from parse_oid_hex that points after
the parsed object ID.

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

diff --git a/builtin/mktree.c b/builtin/mktree.c
index 2dc4ad6ba8..94e82b8504 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c
@@ -98,7 +98,7 @@ static void mktree_line(char *buf, size_t len, int nul_term_line, int allow_miss
 
 	*ntr++ = 0; /* now at the beginning of SHA1 */
 
-	path = ntr + 41;  /* at the beginning of name */
+	path = (char *)p + 1;  /* at the beginning of name */
 	if (!nul_term_line && path[0] == '"') {
 		struct strbuf p_uq = STRBUF_INIT;
 		if (unquote_c_style(&p_uq, path, NULL))

[PATCH v2 05/15] builtin/fetch-pack: remove constants with parse_oid_hex

[brian m. carlson]

Instead of using GIT_SHA1_HEXSZ, use parse_oid_hex to compute a pointer
and use that in comparisons.  This is both simpler to read and works
independent of the hash length.  Update references to SHA-1 in the same
function to refer to object IDs instead.

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

diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index 1a1bc63566..63e69a5801 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -16,13 +16,14 @@ static void add_sought_entry(struct ref ***sought, int *nr, int *alloc,
 {
 	struct ref *ref;
 	struct object_id oid;
+	const char *p;
 
-	if (!get_oid_hex(name, &oid)) {
-		if (name[GIT_SHA1_HEXSZ] == ' ') {
-			/* <sha1> <ref>, find refname */
-			name += GIT_SHA1_HEXSZ + 1;
-		} else if (name[GIT_SHA1_HEXSZ] == '\0') {
-			; /* <sha1>, leave sha1 as name */
+	if (!parse_oid_hex(name, &oid, &p)) {
+		if (*p == ' ') {
+			/* <oid> <ref>, find refname */
+			name = p + 1;
+		} else if (*p == '\0') {
+			; /* <oid>, leave oid as name */
 		} else {
 			/* <ref>, clear cruft from oid */
 			oidclr(&oid);

[PATCH v2 06/15] pack-revindex: express constants in terms of the_hash_algo

[brian m. carlson]

Express the various constants used in terms of the_hash_algo.
While we're at it, fix a comment style issue as well.

Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 pack-revindex.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/pack-revindex.c b/pack-revindex.c
index bb521cf7fb..3c58784a5f 100644
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -122,13 +122,14 @@ static void create_pack_revindex(struct packed_git *p)
 	unsigned num_ent = p->num_objects;
 	unsigned i;
 	const char *index = p->index_data;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	ALLOC_ARRAY(p->revindex, num_ent + 1);
 	index += 4 * 256;
 
 	if (p->index_version > 1) {
 		const uint32_t *off_32 =
-			(uint32_t *)(index + 8 + p->num_objects * (20 + 4));
+			(uint32_t *)(index + 8 + p->num_objects * (hashsz + 4));
 		const uint32_t *off_64 = off_32 + p->num_objects;
 		for (i = 0; i < num_ent; i++) {
 			uint32_t off = ntohl(*off_32++);
@@ -142,16 +143,17 @@ static void create_pack_revindex(struct packed_git *p)
 		}
 	} else {
 		for (i = 0; i < num_ent; i++) {
-			uint32_t hl = *((uint32_t *)(index + 24 * i));
+			uint32_t hl = *((uint32_t *)(index + (hashsz + 4) * i));
 			p->revindex[i].offset = ntohl(hl);
 			p->revindex[i].nr = i;
 		}
 	}
 
-	/* This knows the pack format -- the 20-byte trailer
+	/*
+	 * This knows the pack format -- the hash trailer
 	 * follows immediately after the last object data.
 	 */
-	p->revindex[num_ent].offset = p->pack_size - 20;
+	p->revindex[num_ent].offset = p->pack_size - hashsz;
 	p->revindex[num_ent].nr = -1;
 	sort_revindex(p->revindex, num_ent, p->pack_size);
 }

[PATCH v2 07/15] packfile: express constants in terms of the_hash_algo

[brian m. carlson]

Replace uses of GIT_SHA1_RAWSZ with references to the_hash_algo to avoid
dependence on a particular hash length.

It's likely that in the future, we'll update the pack format to indicate
what hash algorithm it uses, and then this code will change.  However,
at least on an interim basis, make it easier to develop on a pure
SHA-256 Git by using the_hash_algo here.

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

diff --git a/packfile.c b/packfile.c
index 841b36182f..17f993b5bf 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1121,13 +1121,14 @@ int unpack_object_header(struct packed_git *p,
 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
 {
 	unsigned i;
+	const unsigned hashsz = the_hash_algo->rawsz;
 	for (i = 0; i < p->num_bad_objects; i++)
-		if (hasheq(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
+		if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
 			return;
 	p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
 				      st_mult(GIT_MAX_RAWSZ,
 					      st_add(p->num_bad_objects, 1)));
-	hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
+	hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
 	p->num_bad_objects++;
 }
 

[PATCH v2 08/15] refs/packed-backend: express constants using the_hash_algo

[brian m. carlson]

Switch uses of GIT_SHA1_HEXSZ to use the_hash_algo so that they are
appropriate for the any given hash length.

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

diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 74e2996e93..c01c7f5901 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -274,8 +274,8 @@ struct snapshot_record {
 static int cmp_packed_ref_records(const void *v1, const void *v2)
 {
 	const struct snapshot_record *e1 = v1, *e2 = v2;
-	const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1;
-	const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1;
+	const char *r1 = e1->start + the_hash_algo->hexsz + 1;
+	const char *r2 = e2->start + the_hash_algo->hexsz + 1;
 
 	while (1) {
 		if (*r1 == '\n')
@@ -297,7 +297,7 @@ static int cmp_packed_ref_records(const void *v1, const void *v2)
  */
 static int cmp_record_to_refname(const char *rec, const char *refname)
 {
-	const char *r1 = rec + GIT_SHA1_HEXSZ + 1;
+	const char *r1 = rec + the_hash_algo->hexsz + 1;
 	const char *r2 = refname;
 
 	while (1) {
@@ -344,7 +344,7 @@ static void sort_snapshot(struct snapshot *snapshot)
 		if (!eol)
 			/* The safety check should prevent this. */
 			BUG("unterminated line found in packed-refs");
-		if (eol - pos < GIT_SHA1_HEXSZ + 2)
+		if (eol - pos < the_hash_algo->hexsz + 2)
 			die_invalid_line(snapshot->refs->path,
 					 pos, eof - pos);
 		eol++;
@@ -456,7 +456,7 @@ static void verify_buffer_safe(struct snapshot *snapshot)
 		return;
 
 	last_line = find_start_of_record(start, eof - 1);
-	if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2)
+	if (*(eof - 1) != '\n' || eof - last_line < the_hash_algo->hexsz + 2)
 		die_invalid_line(snapshot->refs->path,
 				 last_line, eof - last_line);
 }
@@ -796,7 +796,7 @@ static int next_record(struct packed_ref_iterator *iter)
 
 	iter->base.flags = REF_ISPACKED;
 
-	if (iter->eof - p < GIT_SHA1_HEXSZ + 2 ||
+	if (iter->eof - p < the_hash_algo->hexsz + 2 ||
 	    parse_oid_hex(p, &iter->oid, &p) ||
 	    !isspace(*p++))
 		die_invalid_line(iter->snapshot->refs->path,
@@ -826,7 +826,7 @@ static int next_record(struct packed_ref_iterator *iter)
 
 	if (iter->pos < iter->eof && *iter->pos == '^') {
 		p = iter->pos + 1;
-		if (iter->eof - p < GIT_SHA1_HEXSZ + 1 ||
+		if (iter->eof - p < the_hash_algo->hexsz + 1 ||
 		    parse_oid_hex(p, &iter->peeled, &p) ||
 		    *p++ != '\n')
 			die_invalid_line(iter->snapshot->refs->path,

[PATCH v2 09/15] upload-pack: express constants in terms of the_hash_algo

[brian m. carlson]

Convert all uses of the GIT_SHA1_HEXSZ to use the_hash_algo so that they
are appropriate for any given hash length.

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

diff --git a/upload-pack.c b/upload-pack.c
index 62a1000f44..1aae5dd828 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -443,6 +443,7 @@ static int do_reachable_revlist(struct child_process *cmd,
 	struct object *o;
 	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
 	int i;
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	cmd->argv = argv;
 	cmd->git_cmd = 1;
@@ -461,7 +462,7 @@ static int do_reachable_revlist(struct child_process *cmd,
 		goto error;
 
 	namebuf[0] = '^';
-	namebuf[GIT_SHA1_HEXSZ + 1] = '\n';
+	namebuf[hexsz + 1] = '\n';
 	for (i = get_max_object_index(); 0 < i; ) {
 		o = get_indexed_object(--i);
 		if (!o)
@@ -470,11 +471,11 @@ static int do_reachable_revlist(struct child_process *cmd,
 			o->flags &= ~TMP_MARK;
 		if (!is_our_ref(o))
 			continue;
-		memcpy(namebuf + 1, oid_to_hex(&o->oid), GIT_SHA1_HEXSZ);
-		if (write_in_full(cmd->in, namebuf, GIT_SHA1_HEXSZ + 2) < 0)
+		memcpy(namebuf + 1, oid_to_hex(&o->oid), hexsz);
+		if (write_in_full(cmd->in, namebuf, hexsz + 2) < 0)
 			goto error;
 	}
-	namebuf[GIT_SHA1_HEXSZ] = '\n';
+	namebuf[hexsz] = '\n';
 	for (i = 0; i < src->nr; i++) {
 		o = src->objects[i].item;
 		if (is_our_ref(o)) {
@@ -484,8 +485,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 		}
 		if (reachable && o->type == OBJ_COMMIT)
 			o->flags |= TMP_MARK;
-		memcpy(namebuf, oid_to_hex(&o->oid), GIT_SHA1_HEXSZ);
-		if (write_in_full(cmd->in, namebuf, GIT_SHA1_HEXSZ + 1) < 0)
+		memcpy(namebuf, oid_to_hex(&o->oid), hexsz);
+		if (write_in_full(cmd->in, namebuf, hexsz + 1) < 0)
 			goto error;
 	}
 	close(cmd->in);

[PATCH v2 10/15] transport: use parse_oid_hex instead of a constant

[brian m. carlson]

Use parse_oid_hex to compute a pointer instead of using GIT_SHA1_HEXSZ.
This simplifies the code and makes it independent of the hash length.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 transport.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/transport.c b/transport.c
index 1c76d64aba..44b9ddf670 100644
--- a/transport.c
+++ b/transport.c
@@ -1346,15 +1346,16 @@ static void read_alternate_refs(const char *path,
 	fh = xfdopen(cmd.out, "r");
 	while (strbuf_getline_lf(&line, fh) != EOF) {
 		struct object_id oid;
+		const char *p;
 
-		if (get_oid_hex(line.buf, &oid) ||
-		    line.buf[GIT_SHA1_HEXSZ] != ' ') {
+		if (parse_oid_hex(line.buf, &oid, &p) ||
+		    *p != ' ') {
 			warning(_("invalid line while parsing alternate refs: %s"),
 				line.buf);
 			break;
 		}
 
-		cb(line.buf + GIT_SHA1_HEXSZ + 1, &oid, data);
+		cb(p + 1, &oid, data);
 	}
 
 	fclose(fh);

[PATCH v2 11/15] tag: express constant in terms of the_hash_algo

[brian m. carlson]

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

diff --git a/tag.c b/tag.c
index 1db663d716..7445b8f6ea 100644
--- a/tag.c
+++ b/tag.c
@@ -144,7 +144,7 @@ int parse_tag_buffer(struct repository *r, struct tag *item, const void *data, u
 		return 0;
 	item->object.parsed = 1;
 
-	if (size < GIT_SHA1_HEXSZ + 24)
+	if (size < the_hash_algo->hexsz + 24)
 		return -1;
 	if (memcmp("object ", bufptr, 7) || parse_oid_hex(bufptr + 7, &oid, &bufptr) || *bufptr++ != '\n')
 		return -1;

[PATCH v2 12/15] apply: replace hard-coded constants

[brian m. carlson]

Replace several 40-based constants with references to GIT_MAX_HEXSZ or
the_hash_algo, as appropriate.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 apply.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/apply.c b/apply.c
index e485fbc6bc..792ecea36a 100644
--- a/apply.c
+++ b/apply.c
@@ -223,8 +223,8 @@ struct patch {
 	struct fragment *fragments;
 	char *result;
 	size_t resultsize;
-	char old_sha1_prefix[41];
-	char new_sha1_prefix[41];
+	char old_sha1_prefix[GIT_MAX_HEXSZ + 1];
+	char new_sha1_prefix[GIT_MAX_HEXSZ + 1];
 	struct patch *next;
 
 	/* three-way fallback result */
@@ -1093,9 +1093,10 @@ static int gitdiff_index(struct apply_state *state,
 	 */
 	const char *ptr, *eol;
 	int len;
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	ptr = strchr(line, '.');
-	if (!ptr || ptr[1] != '.' || 40 < ptr - line)
+	if (!ptr || ptr[1] != '.' || hexsz < ptr - line)
 		return 0;
 	len = ptr - line;
 	memcpy(patch->old_sha1_prefix, line, len);
@@ -1109,7 +1110,7 @@ static int gitdiff_index(struct apply_state *state,
 		ptr = eol;
 	len = ptr - line;
 
-	if (40 < len)
+	if (hexsz < len)
 		return 0;
 	memcpy(patch->new_sha1_prefix, line, len);
 	patch->new_sha1_prefix[len] = 0;
@@ -3142,13 +3143,14 @@ static int apply_binary(struct apply_state *state,
 {
 	const char *name = patch->old_name ? patch->old_name : patch->new_name;
 	struct object_id oid;
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	/*
 	 * For safety, we require patch index line to contain
-	 * full 40-byte textual SHA1 for old and new, at least for now.
+	 * full hex textual object ID for old and new, at least for now.
 	 */
-	if (strlen(patch->old_sha1_prefix) != 40 ||
-	    strlen(patch->new_sha1_prefix) != 40 ||
+	if (strlen(patch->old_sha1_prefix) != hexsz ||
+	    strlen(patch->new_sha1_prefix) != hexsz ||
 	    get_oid_hex(patch->old_sha1_prefix, &oid) ||
 	    get_oid_hex(patch->new_sha1_prefix, &oid))
 		return error(_("cannot apply binary patch to '%s' "
@@ -4055,7 +4057,7 @@ static int preimage_oid_in_gitlink_patch(struct patch *p, struct object_id *oid)
 	    starts_with(++preimage, heading) &&
 	    /* does it record full SHA-1? */
 	    !get_oid_hex(preimage + sizeof(heading) - 1, oid) &&
-	    preimage[sizeof(heading) + GIT_SHA1_HEXSZ - 1] == '\n' &&
+	    preimage[sizeof(heading) + the_hash_algo->hexsz - 1] == '\n' &&
 	    /* does the abbreviated name on the index line agree with it? */
 	    starts_with(preimage + sizeof(heading) - 1, p->old_sha1_prefix))
 		return 0; /* it all looks fine */

[PATCH v2 13/15] apply: rename new_sha1_prefix and old_sha1_prefix

[brian m. carlson]

Rename these structure members to "new_oid_prefix" and "old_oid_prefix".

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 apply.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/apply.c b/apply.c
index 792ecea36a..b9eb02ec12 100644
--- a/apply.c
+++ b/apply.c
@@ -223,8 +223,8 @@ struct patch {
 	struct fragment *fragments;
 	char *result;
 	size_t resultsize;
-	char old_sha1_prefix[GIT_MAX_HEXSZ + 1];
-	char new_sha1_prefix[GIT_MAX_HEXSZ + 1];
+	char old_oid_prefix[GIT_MAX_HEXSZ + 1];
+	char new_oid_prefix[GIT_MAX_HEXSZ + 1];
 	struct patch *next;
 
 	/* three-way fallback result */
@@ -1099,8 +1099,8 @@ static int gitdiff_index(struct apply_state *state,
 	if (!ptr || ptr[1] != '.' || hexsz < ptr - line)
 		return 0;
 	len = ptr - line;
-	memcpy(patch->old_sha1_prefix, line, len);
-	patch->old_sha1_prefix[len] = 0;
+	memcpy(patch->old_oid_prefix, line, len);
+	patch->old_oid_prefix[len] = 0;
 
 	line = ptr + 2;
 	ptr = strchr(line, ' ');
@@ -1112,8 +1112,8 @@ static int gitdiff_index(struct apply_state *state,
 
 	if (hexsz < len)
 		return 0;
-	memcpy(patch->new_sha1_prefix, line, len);
-	patch->new_sha1_prefix[len] = 0;
+	memcpy(patch->new_oid_prefix, line, len);
+	patch->new_oid_prefix[len] = 0;
 	if (*ptr == ' ')
 		return gitdiff_oldmode(state, ptr + 1, patch);
 	return 0;
@@ -2205,7 +2205,7 @@ static void reverse_patches(struct patch *p)
 		SWAP(p->new_mode, p->old_mode);
 		SWAP(p->is_new, p->is_delete);
 		SWAP(p->lines_added, p->lines_deleted);
-		SWAP(p->old_sha1_prefix, p->new_sha1_prefix);
+		SWAP(p->old_oid_prefix, p->new_oid_prefix);
 
 		for (; frag; frag = frag->next) {
 			SWAP(frag->newpos, frag->oldpos);
@@ -3149,10 +3149,10 @@ static int apply_binary(struct apply_state *state,
 	 * For safety, we require patch index line to contain
 	 * full hex textual object ID for old and new, at least for now.
 	 */
-	if (strlen(patch->old_sha1_prefix) != hexsz ||
-	    strlen(patch->new_sha1_prefix) != hexsz ||
-	    get_oid_hex(patch->old_sha1_prefix, &oid) ||
-	    get_oid_hex(patch->new_sha1_prefix, &oid))
+	if (strlen(patch->old_oid_prefix) != hexsz ||
+	    strlen(patch->new_oid_prefix) != hexsz ||
+	    get_oid_hex(patch->old_oid_prefix, &oid) ||
+	    get_oid_hex(patch->new_oid_prefix, &oid))
 		return error(_("cannot apply binary patch to '%s' "
 			       "without full index line"), name);
 
@@ -3162,7 +3162,7 @@ static int apply_binary(struct apply_state *state,
 		 * applies to.
 		 */
 		hash_object_file(img->buf, img->len, blob_type, &oid);
-		if (strcmp(oid_to_hex(&oid), patch->old_sha1_prefix))
+		if (strcmp(oid_to_hex(&oid), patch->old_oid_prefix))
 			return error(_("the patch applies to '%s' (%s), "
 				       "which does not match the "
 				       "current contents."),
@@ -3175,7 +3175,7 @@ static int apply_binary(struct apply_state *state,
 				       "'%s' but it is not empty"), name);
 	}
 
-	get_oid_hex(patch->new_sha1_prefix, &oid);
+	get_oid_hex(patch->new_oid_prefix, &oid);
 	if (is_null_oid(&oid)) {
 		clear_image(img);
 		return 0; /* deletion patch */
@@ -3191,7 +3191,7 @@ static int apply_binary(struct apply_state *state,
 		if (!result)
 			return error(_("the necessary postimage %s for "
 				       "'%s' cannot be read"),
-				     patch->new_sha1_prefix, name);
+				     patch->new_oid_prefix, name);
 		clear_image(img);
 		img->buf = result;
 		img->len = size;
@@ -3207,9 +3207,9 @@ static int apply_binary(struct apply_state *state,
 
 		/* verify that the result matches */
 		hash_object_file(img->buf, img->len, blob_type, &oid);
-		if (strcmp(oid_to_hex(&oid), patch->new_sha1_prefix))
+		if (strcmp(oid_to_hex(&oid), patch->new_oid_prefix))
 			return error(_("binary patch to '%s' creates incorrect result (expecting %s, got %s)"),
-				name, patch->new_sha1_prefix, oid_to_hex(&oid));
+				name, patch->new_oid_prefix, oid_to_hex(&oid));
 	}
 
 	return 0;
@@ -3565,7 +3565,7 @@ static int try_threeway(struct apply_state *state,
 	/* Preimage the patch was prepared for */
 	if (patch->is_new)
 		write_object_file("", 0, blob_type, &pre_oid);
-	else if (get_oid(patch->old_sha1_prefix, &pre_oid) ||
+	else if (get_oid(patch->old_oid_prefix, &pre_oid) ||
 		 read_blob_object(&buf, &pre_oid, patch->old_mode))
 		return error(_("repository lacks the necessary blob to fall back on 3-way merge."));
 
@@ -4059,11 +4059,11 @@ static int preimage_oid_in_gitlink_patch(struct patch *p, struct object_id *oid)
 	    !get_oid_hex(preimage + sizeof(heading) - 1, oid) &&
 	    preimage[sizeof(heading) + the_hash_algo->hexsz - 1] == '\n' &&
 	    /* does the abbreviated name on the index line agree with it? */
-	    starts_with(preimage + sizeof(heading) - 1, p->old_sha1_prefix))
+	    starts_with(preimage + sizeof(heading) - 1, p->old_oid_prefix))
 		return 0; /* it all looks fine */
 
 	/* we may have full object name on the index line */
-	return get_oid_hex(p->old_sha1_prefix, oid);
+	return get_oid_hex(p->old_oid_prefix, oid);
 }
 
 /* Build an index that contains just the files needed for a 3way merge */
@@ -4092,7 +4092,7 @@ static int build_fake_ancestor(struct apply_state *state, struct patch *list)
 			else
 				return error(_("sha1 information is lacking or "
 					       "useless for submodule %s"), name);
-		} else if (!get_oid_blob(patch->old_sha1_prefix, &oid)) {
+		} else if (!get_oid_blob(patch->old_oid_prefix, &oid)) {
 			; /* ok */
 		} else if (!patch->lines_added && !patch->lines_deleted) {
 			/* mode-only change: update the current */

[PATCH v2 14/15] submodule: make zero-oid comparison hash function agnostic

[brian m. carlson]

With SHA-256, the length of the all-zeros object ID is longer.  Add a
function to git-submodule.sh to check if a full hex object ID is the
all-zeros value, and use it to check the output we're parsing from git
diff-files or diff-index.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 git-submodule.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index 1b568e29b9..c09eb3e03d 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -82,6 +82,11 @@ isnumber()
 	n=$(($1 + 0)) 2>/dev/null && test "$n" = "$1"
 }
 
+# Given a full hex object ID, is this the zero OID?
+is_zero_oid () {
+	echo "$1" | sane_egrep '^0+$' >/dev/null 2>&1
+}
+
 # Sanitize the local git environment for use within a submodule. We
 # can't simply use clear_local_git_env since we want to preserve some
 # of the settings from GIT_CONFIG_PARAMETERS.
@@ -780,7 +785,7 @@ cmd_summary() {
 	while read -r mod_src mod_dst sha1_src sha1_dst status name
 	do
 		if test -z "$cached" &&
-			test $sha1_dst = 0000000000000000000000000000000000000000
+			is_zero_oid $sha1_dst
 		then
 			case "$mod_dst" in
 			160000)

[PATCH v2 15/15] rerere: convert to use the_hash_algo

[brian m. carlson]

Since this data is stored in the .git directory, it makes sense for us
to use the same hash algorithm for it as for everything else.  Convert
the remaining uses of SHA-1 to use the_hash_algo.  Use GIT_MAX_RAWSZ for
allocations.  Rename various struct members, local variables, and a
function to be named "hash" instead of "sha1".

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 rerere.c | 81 +++++++++++++++++++++++++++++---------------------------
 1 file changed, 42 insertions(+), 39 deletions(-)

diff --git a/rerere.c b/rerere.c
index 7aa149e849..ceb98015ff 100644
--- a/rerere.c
+++ b/rerere.c
@@ -29,7 +29,7 @@ static int rerere_dir_alloc;
 #define RR_HAS_POSTIMAGE 1
 #define RR_HAS_PREIMAGE 2
 static struct rerere_dir {
-	unsigned char sha1[20];
+	unsigned char hash[GIT_MAX_HEXSZ];
 	int status_alloc, status_nr;
 	unsigned char *status;
 } **rerere_dir;
@@ -52,7 +52,7 @@ static void free_rerere_id(struct string_list_item *item)
 
 static const char *rerere_id_hex(const struct rerere_id *id)
 {
-	return sha1_to_hex(id->collection->sha1);
+	return sha1_to_hex(id->collection->hash);
 }
 
 static void fit_variant(struct rerere_dir *rr_dir, int variant)
@@ -115,7 +115,7 @@ static int is_rr_file(const char *name, const char *filename, int *variant)
 static void scan_rerere_dir(struct rerere_dir *rr_dir)
 {
 	struct dirent *de;
-	DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->sha1)));
+	DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->hash)));
 
 	if (!dir)
 		return;
@@ -133,24 +133,24 @@ static void scan_rerere_dir(struct rerere_dir *rr_dir)
 	closedir(dir);
 }
 
-static const unsigned char *rerere_dir_sha1(size_t i, void *table)
+static const unsigned char *rerere_dir_hash(size_t i, void *table)
 {
 	struct rerere_dir **rr_dir = table;
-	return rr_dir[i]->sha1;
+	return rr_dir[i]->hash;
 }
 
 static struct rerere_dir *find_rerere_dir(const char *hex)
 {
-	unsigned char sha1[20];
+	unsigned char hash[GIT_MAX_RAWSZ];
 	struct rerere_dir *rr_dir;
 	int pos;
 
-	if (get_sha1_hex(hex, sha1))
+	if (get_sha1_hex(hex, hash))
 		return NULL; /* BUG */
-	pos = sha1_pos(sha1, rerere_dir, rerere_dir_nr, rerere_dir_sha1);
+	pos = sha1_pos(hash, rerere_dir, rerere_dir_nr, rerere_dir_hash);
 	if (pos < 0) {
 		rr_dir = xmalloc(sizeof(*rr_dir));
-		hashcpy(rr_dir->sha1, sha1);
+		hashcpy(rr_dir->hash, hash);
 		rr_dir->status = NULL;
 		rr_dir->status_nr = 0;
 		rr_dir->status_alloc = 0;
@@ -207,26 +207,27 @@ static void read_rr(struct string_list *rr)
 		return;
 	while (!strbuf_getwholeline(&buf, in, '\0')) {
 		char *path;
-		unsigned char sha1[20];
+		unsigned char hash[GIT_MAX_RAWSZ];
 		struct rerere_id *id;
 		int variant;
+		const unsigned hexsz = the_hash_algo->hexsz;
 
 		/* There has to be the hash, tab, path and then NUL */
-		if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
+		if (buf.len < hexsz + 2 || get_sha1_hex(buf.buf, hash))
 			die(_("corrupt MERGE_RR"));
 
-		if (buf.buf[40] != '.') {
+		if (buf.buf[hexsz] != '.') {
 			variant = 0;
-			path = buf.buf + 40;
+			path = buf.buf + hexsz;
 		} else {
 			errno = 0;
-			variant = strtol(buf.buf + 41, &path, 10);
+			variant = strtol(buf.buf + hexsz + 1, &path, 10);
 			if (errno)
 				die(_("corrupt MERGE_RR"));
 		}
 		if (*(path++) != '\t')
 			die(_("corrupt MERGE_RR"));
-		buf.buf[40] = '\0';
+		buf.buf[hexsz] = '\0';
 		id = new_rerere_id_hex(buf.buf);
 		id->variant = variant;
 		string_list_insert(rr, path)->util = id;
@@ -360,7 +361,7 @@ static void rerere_strbuf_putconflict(struct strbuf *buf, int ch, size_t size)
 }
 
 static int handle_conflict(struct strbuf *out, struct rerere_io *io,
-			   int marker_size, git_SHA_CTX *ctx)
+			   int marker_size, git_hash_ctx *ctx)
 {
 	enum {
 		RR_SIDE_1 = 0, RR_SIDE_2, RR_ORIGINAL
@@ -398,10 +399,12 @@ static int handle_conflict(struct strbuf *out, struct rerere_io *io,
 			strbuf_addbuf(out, &two);
 			rerere_strbuf_putconflict(out, '>', marker_size);
 			if (ctx) {
-				git_SHA1_Update(ctx, one.buf ? one.buf : "",
-					    one.len + 1);
-				git_SHA1_Update(ctx, two.buf ? two.buf : "",
-					    two.len + 1);
+				the_hash_algo->update_fn(ctx, one.buf ?
+							 one.buf : "",
+							 one.len + 1);
+				the_hash_algo->update_fn(ctx, two.buf ?
+							 two.buf : "",
+							 two.len + 1);
 			}
 			break;
 		} else if (hunk == RR_SIDE_1)
@@ -430,18 +433,18 @@ static int handle_conflict(struct strbuf *out, struct rerere_io *io,
  * Return 1 if conflict hunks are found, 0 if there are no conflict
  * hunks and -1 if an error occured.
  */
-static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
+static int handle_path(unsigned char *hash, struct rerere_io *io, int marker_size)
 {
-	git_SHA_CTX ctx;
+	git_hash_ctx ctx;
 	struct strbuf buf = STRBUF_INIT, out = STRBUF_INIT;
 	int has_conflicts = 0;
-	if (sha1)
-		git_SHA1_Init(&ctx);
+	if (hash)
+		the_hash_algo->init_fn(&ctx);
 
 	while (!io->getline(&buf, io)) {
 		if (is_cmarker(buf.buf, '<', marker_size)) {
 			has_conflicts = handle_conflict(&out, io, marker_size,
-							sha1 ? &ctx : NULL);
+							hash ? &ctx : NULL);
 			if (has_conflicts < 0)
 				break;
 			rerere_io_putmem(out.buf, out.len, io);
@@ -452,8 +455,8 @@ static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_siz
 	strbuf_release(&buf);
 	strbuf_release(&out);
 
-	if (sha1)
-		git_SHA1_Final(sha1, &ctx);
+	if (hash)
+		the_hash_algo->final_fn(hash, &ctx);
 
 	return has_conflicts;
 }
@@ -462,7 +465,7 @@ static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_siz
  * Scan the path for conflicts, do the "handle_path()" thing above, and
  * return the number of conflict hunks found.
  */
-static int handle_file(const char *path, unsigned char *sha1, const char *output)
+static int handle_file(const char *path, unsigned char *hash, const char *output)
 {
 	int has_conflicts = 0;
 	struct rerere_io_file io;
@@ -484,7 +487,7 @@ static int handle_file(const char *path, unsigned char *sha1, const char *output
 		}
 	}
 
-	has_conflicts = handle_path(sha1, (struct rerere_io *)&io, marker_size);
+	has_conflicts = handle_path(hash, (struct rerere_io *)&io, marker_size);
 
 	fclose(io.input);
 	if (io.io.wrerror)
@@ -814,7 +817,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 	 */
 	for (i = 0; i < conflict.nr; i++) {
 		struct rerere_id *id;
-		unsigned char sha1[20];
+		unsigned char hash[GIT_MAX_RAWSZ];
 		const char *path = conflict.items[i].string;
 		int ret;
 
@@ -823,7 +826,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 		 * conflict ID.  No need to write anything out
 		 * yet.
 		 */
-		ret = handle_file(path, sha1, NULL);
+		ret = handle_file(path, hash, NULL);
 		if (ret != 0 && string_list_has_string(rr, path)) {
 			remove_variant(string_list_lookup(rr, path)->util);
 			string_list_remove(rr, path, 1);
@@ -831,7 +834,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 		if (ret < 1)
 			continue;
 
-		id = new_rerere_id(sha1);
+		id = new_rerere_id(hash);
 		string_list_insert(rr, path)->util = id;
 
 		/* Ensure that the directory exists. */
@@ -942,7 +945,7 @@ static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
 	return 0;
 }
 
-static int handle_cache(const char *path, unsigned char *sha1, const char *output)
+static int handle_cache(const char *path, unsigned char *hash, const char *output)
 {
 	mmfile_t mmfile[3] = {{NULL}};
 	mmbuffer_t result = {NULL, 0};
@@ -1001,7 +1004,7 @@ static int handle_cache(const char *path, unsigned char *sha1, const char *outpu
 	 * Grab the conflict ID and optionally write the original
 	 * contents with conflict markers out.
 	 */
-	has_conflicts = handle_path(sha1, (struct rerere_io *)&io, marker_size);
+	has_conflicts = handle_path(hash, (struct rerere_io *)&io, marker_size);
 	strbuf_release(&io.input);
 	if (io.io.output)
 		fclose(io.io.output);
@@ -1012,7 +1015,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
 {
 	const char *filename;
 	struct rerere_id *id;
-	unsigned char sha1[20];
+	unsigned char hash[GIT_MAX_RAWSZ];
 	int ret;
 	struct string_list_item *item;
 
@@ -1020,12 +1023,12 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
 	 * Recreate the original conflict from the stages in the
 	 * index and compute the conflict ID
 	 */
-	ret = handle_cache(path, sha1, NULL);
+	ret = handle_cache(path, hash, NULL);
 	if (ret < 1)
 		return error(_("could not parse conflict hunks in '%s'"), path);
 
 	/* Nuke the recorded resolution for the conflict */
-	id = new_rerere_id(sha1);
+	id = new_rerere_id(hash);
 
 	for (id->variant = 0;
 	     id->variant < id->collection->status_nr;
@@ -1037,7 +1040,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
 		if (!has_rerere_resolution(id))
 			continue;
 
-		handle_cache(path, sha1, rerere_path(id, "thisimage"));
+		handle_cache(path, hash, rerere_path(id, "thisimage"));
 		if (read_mmfile(&cur, rerere_path(id, "thisimage"))) {
 			free(cur.ptr);
 			error(_("failed to update conflicted state in '%s'"), path);
@@ -1069,7 +1072,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
 	 * conflict in the working tree, run us again to record
 	 * the postimage.
 	 */
-	handle_cache(path, sha1, rerere_path(id, "preimage"));
+	handle_cache(path, hash, rerere_path(id, "preimage"));
 	fprintf_ln(stderr, _("Updated preimage for '%s'"), path);
 
 	/*

Re: [PATCH v2 00/15] Hash function transition part 15

[Junio C Hamano]

"brian m. carlson" <sandals@crustytoothpaste.net> writes:

> This is the fifteenth series in the ongoing hash function transition.
>
> This series includes several conversions to use the_hash_algo, combined
> with some use of parse_oid_hex and GIT_MAX_RAWSZ.
>
> Changes from v1:
> * Fix several other substantially similar issues in builtin/repack.
> * Fix a comment style issue.
> * Improve commit message as suggested by Stefan.
> * Pull in Gábor's patch and place it at the beginning of the series.

The previous round had attracted a handful of suggestions for
changes, and it seems that they are all addressed here.  We haven't
seen any more input, so let's move this to 'next' and to 'master'
soonish.

Thanks.