From 6c4a060d7d895c90610eb442cb4f910fe43ef13a Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 4 Oct 2012 04:02:53 -0400 Subject: [PATCH] peel_ref: check object type before loading The point of peel_ref is to dereference tags; if the base object is not a tag, then we can return early without even loading the object into memory. This patch accomplishes that by checking sha1_object_info for the type. For a packed object, we can get away with just looking in the pack index. For a loose object, we only need to inflate the first couple of header bytes. This is a bit of a gamble; if we do find a tag object, then we will end up loading the content anyway, and the extra lookup will have been wasteful. However, if it is not a tag object, then we save loading the object entirely. Depending on the ratio of non-tags to tags in the input, this can be a minor win or minor loss. However, it does give us one potential major win: if a ref points to a large blob (e.g., via an unannotated tag), then we can avoid looking at it entirely. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- refs.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/refs.c b/refs.c index f672ad93a..02e47b115 100644 --- a/refs.c +++ b/refs.c @@ -1225,8 +1225,15 @@ int peel_ref(const char *refname, unsigned char *sha1) } fallback: - o = parse_object(base); - if (o && o->type == OBJ_TAG) { + o = lookup_unknown_object(base); + if (o->type == OBJ_NONE) { + int type = sha1_object_info(base, NULL); + if (type < 0) + return -1; + o->type = type; + } + + if (o->type == OBJ_TAG) { o = deref_tag_noverify(o); if (o) { hashcpy(sha1, o->sha1); -- 2.26.2