[PATCH] sha1_name: avoid quadratic list insertion in handle_one_ref

[PATCH] sha1_name: avoid quadratic list insertion in handle_one_ref

[René Scharfe]

Similar to 16445242 (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>
---
 sha1_name.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sha1_name.c b/sha1_name.c
index 63ee66f..7098b10 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -839,7 +839,7 @@ 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;
 }
 
@@ -1366,6 +1366,7 @@ 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 ||
-- 
2.1.0

Re: [PATCH] sha1_name: avoid quadratic list insertion in handle_one_ref

[Jeff King]

On Thu, Aug 21, 2014 at 08:30:29PM +0200, René Scharfe wrote:

> Similar to 16445242 (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.

Looks good, thanks.

I was hoping one of these would be fixing the quadratic http-push
behavior I mentioned yesterday, but alas. We seem to have a lot of
quadratic spots to fix. :)

-Peff