[PATCH 08/10] object-file API: replace check_object_signature() with stream_*

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Change the task of the the check_object_signature() function so that
it no longer confusingly does two unrelated things.

Now the "!map" branch of it is exposed as a renamed
stream_object_signature(). In preceding commits we migrated all of the
"if (map)" callers over to "hash_object_file_oideq()" or
"hash_object_file_literally()" followed by "!oideq(...)".

This makes the caller in parse_object() less confusing, as we'll now
no longer need to pass NULL for "map" and "OBJ_BAD" for the unused
"type" argument. The "verify_packfile()" caller is arguably a bit
worse off than before, but as we're only using this function in a
couple of places now a bit more verbosity there is acceptable.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 cache.h       | 11 ++++++++---
 object-file.c | 17 +++--------------
 object.c      |  2 +-
 pack-check.c  |  8 ++++++--
 4 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/cache.h b/cache.h
index d9c68c66d53..881ae36fd47 100644
--- a/cache.h
+++ b/cache.h
@@ -1319,9 +1319,14 @@ enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
 struct object_info;
 int parse_loose_header(const char *hdr, struct object_info *oi);
 
-int check_object_signature(struct repository *r, const struct object_id *oid,
-			   void *buf, unsigned long size, enum object_type type,
-			   struct object_id *real_oidp);
+
+/**
+ * stream_object_signature() tries to read the object named with "oid"
+ * using the streaming interface and rehash it to make sure the object
+ * name actually matches "oid" to detect object corruption.
+ */
+int stream_object_signature(struct repository *r, const struct object_id *oid,
+			    struct object_id *real_oidp);
 
 int finalize_object_file(const char *tmpfile, const char *filename);
 
diff --git a/object-file.c b/object-file.c
index 4a23a7aa79f..27f587d1dcd 100644
--- a/object-file.c
+++ b/object-file.c
@@ -1066,29 +1066,18 @@ int format_object_header(char *str, size_t size, enum object_type type,
 	return format_object_header_literally(str, size, name, objsize);
 }
 
-/*
- * With an in-core object data in "map", rehash it to make sure the
- * object name actually matches "oid" to detect object corruption.
- * With "map" == NULL, try reading the object named with "oid" using
- * the streaming interface and rehash it to do the same.
- */
-int check_object_signature(struct repository *r, const struct object_id *oid,
-			   void *map, unsigned long size, enum object_type type,
-			   struct object_id *real_oidp)
+int stream_object_signature(struct repository *r, const struct object_id *oid,
+			    struct object_id *real_oidp)
 {
 	struct object_id tmp;
 	struct object_id *real_oid = real_oidp ? real_oidp : &tmp;
+	unsigned long size;
 	enum object_type obj_type;
 	struct git_istream *st;
 	git_hash_ctx c;
 	char hdr[MAX_HEADER_LEN];
 	int hdrlen;
 
-	if (map) {
-		hash_object_file(r->hash_algo, map, size, type, real_oid);
-		return !oideq(oid, real_oid) ? -1 : 0;
-	}
-
 	st = open_istream(r, oid, &obj_type, &size, NULL);
 	if (!st)
 		return -1;
diff --git a/object.c b/object.c
index 795b1356a1b..bf51b2056e9 100644
--- a/object.c
+++ b/object.c
@@ -279,7 +279,7 @@ struct object *parse_object(struct repository *r, const struct object_id *oid)
 	if ((obj && obj->type == OBJ_BLOB && repo_has_object_file(r, oid)) ||
 	    (!obj && repo_has_object_file(r, oid) &&
 	     oid_object_info(r, oid, NULL) == OBJ_BLOB)) {
-		if (check_object_signature(r, repl, NULL, 0, OBJ_BAD, NULL) < 0) {
+		if (stream_object_signature(r, repl, NULL) < 0) {
 			error(_("hash mismatch %s"), oid_to_hex(oid));
 			return NULL;
 		}
diff --git a/pack-check.c b/pack-check.c
index faceae610d3..5d5169507ec 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -142,8 +142,12 @@ static int verify_packfile(struct repository *r,
 			err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
 				    oid_to_hex(&oid), p->pack_name,
 				    (uintmax_t)entries[i].offset);
-		else if (check_object_signature(r, &oid, data, size,
-						type, NULL))
+		else if (data && !hash_object_file_oideq(r->hash_algo, data,
+							 size, type, &oid,
+							 NULL))
+			err = error("packed %s from %s is corrupt",
+				    oid_to_hex(&oid), p->pack_name);
+		else if (!data && stream_object_signature(r, &oid, NULL))
 			err = error("packed %s from %s is corrupt",
 				    oid_to_hex(&oid), p->pack_name);
 		else if (fn) {
-- 
2.35.0.913.g12b4baa2536