packfile: introduce function to read object info from a store

Extract the logic to read object info for a packed object from
`do_oid_object_into_extended()` into a standalone function that operates
on the packfile store. This function will be used in a subsequent
commit.

Note that this change allows us to make `find_pack_entry()` an internal
implementation detail. As a consequence though we have to move around
`packfile_store_freshen_object()` so that it is defined after that
function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

odb.c

@@ -666,8 +666,6 @@ static int do_oid_object_info_extended(struct object_database *odb,
 {
 	static struct object_info blank_oi = OBJECT_INFO_INIT;
 	const struct cached_object *co;
-	struct pack_entry e;
-	int rtype;
 	const struct object_id *real = oid;
 	int already_retried = 0;
 
@@ -702,8 +700,8 @@ static int do_oid_object_info_extended(struct object_database *odb,
 	while (1) {
 		struct odb_source *source;
 
-		if (find_pack_entry(odb->repo, real, &e))
-			break;
+		if (!packfile_store_read_object_info(odb->packfiles, real, oi, flags))
+			return 0;
 
 		/* Most likely it's a loose object. */
 		for (source = odb->sources; source; source = source->next)
@@ -713,8 +711,8 @@ static int do_oid_object_info_extended(struct object_database *odb,
 		/* Not a loose object; someone else may have just packed it. */
 		if (!(flags & OBJECT_INFO_QUICK)) {
 			odb_reprepare(odb->repo->objects);
-			if (find_pack_entry(odb->repo, real, &e))
-				break;
+			if (!packfile_store_read_object_info(odb->packfiles, real, oi, flags))
+				return 0;
 		}
 
 		/*
@@ -747,25 +745,6 @@ static int do_oid_object_info_extended(struct object_database *odb,
 		}
 		return -1;
 	}
-
-	if (oi == &blank_oi)
-		/*
-		 * We know that the caller doesn't actually need the
-		 * information below, so return early.
-		 */
-		return 0;
-	rtype = packed_object_info(odb->repo, e.p, e.offset, oi);
-	if (rtype < 0) {
-		mark_bad_packed_object(e.p, real);
-		return do_oid_object_info_extended(odb, real, oi, 0);
-	} else if (oi->whence == OI_PACKED) {
-		oi->u.packed.offset = e.offset;
-		oi->u.packed.pack = e.p;
-		oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
-					 rtype == OBJ_OFS_DELTA);
-	}
-
-	return 0;
 }
 
 static int oid_object_info_convert(struct repository *r,

packfile.c

@@ -819,22 +819,6 @@ struct packed_git *packfile_store_load_pack(struct packfile_store *store,
 	return p;
 }
 
-int packfile_store_freshen_object(struct packfile_store *store,
-				  const struct object_id *oid)
-{
-	struct pack_entry e;
-	if (!find_pack_entry(store->odb->repo, oid, &e))
-		return 0;
-	if (e.p->is_cruft)
-		return 0;
-	if (e.p->freshened)
-		return 1;
-	if (utime(e.p->pack_name, NULL))
-		return 0;
-	e.p->freshened = 1;
-	return 1;
-}
-
 void (*report_garbage)(unsigned seen_bits, const char *path);
 
 static void report_helper(const struct string_list *list,
@@ -2064,7 +2048,9 @@ static int fill_pack_entry(const struct object_id *oid,
 	return 1;
 }
 
-int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
+static int find_pack_entry(struct repository *r,
+			   const struct object_id *oid,
+			   struct pack_entry *e)
 {
 	struct list_head *pos;
 
@@ -2087,6 +2073,57 @@ int find_pack_entry(struct repository *r, const struct object_id *oid, struct pa
 	return 0;
 }
 
+int packfile_store_freshen_object(struct packfile_store *store,
+				  const struct object_id *oid)
+{
+	struct pack_entry e;
+	if (!find_pack_entry(store->odb->repo, oid, &e))
+		return 0;
+	if (e.p->is_cruft)
+		return 0;
+	if (e.p->freshened)
+		return 1;
+	if (utime(e.p->pack_name, NULL))
+		return 0;
+	e.p->freshened = 1;
+	return 1;
+}
+
+int packfile_store_read_object_info(struct packfile_store *store,
+				    const struct object_id *oid,
+				    struct object_info *oi,
+				    unsigned flags UNUSED)
+{
+	static struct object_info blank_oi = OBJECT_INFO_INIT;
+	struct pack_entry e;
+	int rtype;
+
+	if (!find_pack_entry(store->odb->repo, oid, &e))
+		return 1;
+
+	/*
+	 * We know that the caller doesn't actually need the
+	 * information below, so return early.
+	 */
+	if (oi == &blank_oi)
+		return 0;
+
+	rtype = packed_object_info(store->odb->repo, e.p, e.offset, oi);
+	if (rtype < 0) {
+		mark_bad_packed_object(e.p, oid);
+		return -1;
+	}
+
+	if (oi->whence == OI_PACKED) {
+		oi->u.packed.offset = e.offset;
+		oi->u.packed.pack = e.p;
+		oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
+					 rtype == OBJ_OFS_DELTA);
+	}
+
+	return 0;
+}
+
 static void maybe_invalidate_kept_pack_cache(struct repository *r,
 					     unsigned flags)
 {

packfile.h

@@ -144,6 +144,17 @@ void packfile_store_add_pack(struct packfile_store *store,
 #define repo_for_each_pack(repo, p) \
 	for (p = packfile_store_get_packs(repo->objects->packfiles); p; p = p->next)
 
+/*
+ * Try to read the object identified by its ID from the object store and
+ * populate the object info with its data. Returns 1 in case the object was
+ * not found, 0 if it was and read successfully, and a negative error code in
+ * case the object was corrupted.
+ */
+int packfile_store_read_object_info(struct packfile_store *store,
+				    const struct object_id *oid,
+				    struct object_info *oi,
+				    unsigned flags);
+
 /*
  * Get all packs managed by the given store, including packfiles that are
  * referenced by multi-pack indices.
@@ -357,7 +368,6 @@ const struct packed_git *has_packed_and_bad(struct repository *, const struct ob
  * Iff a pack file in the given repository contains the object named by sha1,
  * return true and store its location to e.
  */
-int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e);
 int find_kept_pack_entry(struct repository *r, const struct object_id *oid, unsigned flags, struct pack_entry *e);
 
 int has_object_pack(struct repository *r, const struct object_id *oid);