object: add repository argument to lookup_object

Add a repository argument to allow callers of lookup_object to be more
specific about which repository to handle. This is a small mechanical
change; it doesn't change the implementation to handle repositories
other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

object.c

@@ -84,7 +84,7 @@ static void insert_obj_hash(struct object *obj, struct object **hash, unsigned i
  * Look up the record for the given sha1 in the hash map stored in
  * obj_hash.  Return NULL if it was not found.
  */
-struct object *lookup_object(const unsigned char *sha1)
+struct object *lookup_object_the_repository(const unsigned char *sha1)
 {
 	unsigned int i, first;
 	struct object *obj;
@@ -179,7 +179,7 @@ void *object_as_type(struct object *obj, enum object_type type, int quiet)
 
 struct object *lookup_unknown_object(const unsigned char *sha1)
 {
-	struct object *obj = lookup_object(sha1);
+	struct object *obj = lookup_object(the_repository, sha1);
 	if (!obj)
 		obj = create_object(the_repository, sha1,
 				    alloc_object_node(the_repository));
@@ -255,7 +255,7 @@ struct object *parse_object_the_repository(const struct object_id *oid)
 	void *buffer;
 	struct object *obj;
 
-	obj = lookup_object(oid->hash);
+	obj = lookup_object(the_repository, oid->hash);
 	if (obj && obj->parsed)
 		return obj;
 
@@ -267,7 +267,7 @@ struct object *parse_object_the_repository(const struct object_id *oid)
 			return NULL;
 		}
 		parse_blob_buffer(lookup_blob(oid), NULL, 0);
-		return lookup_object(oid->hash);
+		return lookup_object(the_repository, oid->hash);
 	}
 
 	buffer = read_object_file(oid, &type, &size);