[PATCH] sha1_name: avoid unnecessary sha1 lookup in find_unique_abbrev
- From
Mike Hommey <mh@glandium.org>
- Date
- Nov 26, 2014, 10:12 UTC
- Message-ID
- <1416996767-12672-1-git-send-email-mh@glandium.org>
An example where this happens is when doing an ls-tree on a tree that contains a commit link. In that case, find_unique_abbrev is called to get a non-abbreviated hex sha1, but still, a lookup is done as to whether the sha1 is in the repository (which ends up looking for a loose object in .git/objects), while the result of that lookup is not used when returning a non-abbreviated hex sha1.
Signed-off-by: Mike Hommey <mh@glandium.org> --- sha1_name.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
This hit me on a corner case, where I kind of abuse commit links and have a tree with tens of thousands of them.
Without the patch: $ time git ls-tree -r HEAD | wc -l 114987
real 0m4.412s user 0m1.980s sys 0m2.480s
With the patch: $ time git ls-tree -r HEAD | wc -l 114987
real 0m0.205s user 0m0.196s sys 0m0.012s
diff --git a/sha1_name.c b/sha1_name.c index 5b004f5..cb88170 100644 --- a/sha1_name.c +++ b/sha1_name.c @@ -372,10 +372,10 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len) int status, exists; static char hex[41]; - exists = has_sha1_file(sha1); memcpy(hex, sha1_to_hex(sha1), 40); if (len == 40 || !len) return hex; + exists = has_sha1_file(sha1); while (len < 40) { unsigned char sha1_ret[20]; status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
-- 2.1.1