builtin/pack-objects: use packfile_store_for_each_object()

When enumerating objects that are supposed to be stored in a new cruft
pack we use `for_each_packed_object()` and then derive each object's
mtime individually. Refactor this logic to instead use the new
`packfile_store_for_each_object()` function with an object info request
that asks for the respective mtimes.

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

Author: pks-t

builtin/pack-objects.c

@@ -4314,25 +4314,12 @@ static void show_edge(struct commit *commit)
 }
 
 static int add_object_in_unpacked_pack(const struct object_id *oid,
-				       struct packed_git *pack,
-				       uint32_t pos,
+				       struct object_info *oi,
 				       void *data UNUSED)
 {
 	if (cruft) {
-		off_t offset;
-		time_t mtime;
-
-		if (pack->is_cruft) {
-			if (load_pack_mtimes(pack) < 0)
-				die(_("could not load cruft pack .mtimes"));
-			mtime = nth_packed_mtime(pack, pos);
-		} else {
-			mtime = pack->mtime;
-		}
-		offset = nth_packed_object_offset(pack, pos);
-
-		add_cruft_object_entry(oid, OBJ_NONE, pack, offset,
-				       NULL, mtime);
+		add_cruft_object_entry(oid, OBJ_NONE, oi->u.packed.pack,
+				       oi->u.packed.offset, NULL, *oi->mtimep);
 	} else {
 		add_object_entry(oid, OBJ_NONE, "", 0);
 	}
@@ -4341,14 +4328,25 @@ static int add_object_in_unpacked_pack(const struct object_id *oid,
 
 static void add_objects_in_unpacked_packs(void)
 {
-	if (for_each_packed_object(to_pack.repo,
-				   add_object_in_unpacked_pack,
-				   NULL,
-				   ODB_FOR_EACH_OBJECT_PACK_ORDER |
-				   ODB_FOR_EACH_OBJECT_LOCAL_ONLY |
-				   ODB_FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS |
-				   ODB_FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS))
-		die(_("cannot open pack index"));
+	struct odb_source *source;
+	time_t mtime;
+	struct object_info oi = {
+		.mtimep = &mtime,
+	};
+
+	odb_prepare_alternates(to_pack.repo->objects);
+	for (source = to_pack.repo->objects->sources; source; source = source->next) {
+		if (!source->local)
+			continue;
+
+		if (packfile_store_for_each_object(source->packfiles, &oi,
+						   add_object_in_unpacked_pack, NULL,
+						   ODB_FOR_EACH_OBJECT_PACK_ORDER |
+						   ODB_FOR_EACH_OBJECT_LOCAL_ONLY |
+						   ODB_FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS |
+						   ODB_FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS))
+			die(_("cannot open pack index"));
+	}
 }
 
 static int add_loose_object(const struct object_id *oid, const char *path,