sha1_name: avoid quadratic list insertion in handle_one_ref

Similar to 1644524 (fetch-pack: avoid quadratic list insertion in
mark_complete), sort only after all refs are collected instead of while
inserting.  The result is the same, but it's more efficient that way.
The difference will only be measurable in repositories with a large
number of refs.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_name.c

@@ -835,7 +835,7 @@ static int handle_one_ref(const char *path,
 	}
 	if (object->type != OBJ_COMMIT)
 		return 0;
-	commit_list_insert_by_date((struct commit *)object, list);
+	commit_list_insert((struct commit *)object, list);
 	return 0;
 }
 
@@ -1377,6 +1377,7 @@ static int get_sha1_with_context_1(const char *name,
 		if (!only_to_die && namelen > 2 && name[1] == '/') {
 			struct commit_list *list = NULL;
 			for_each_ref(handle_one_ref, &list);
+			commit_list_sort_by_date(&list);
 			return get_sha1_oneline(name + 2, sha1, list);
 		}
 		if (namelen < 3 ||