sha1_file: do not access pack if unneeded

Currently, regardless of the contents of the "struct object_info" passed
to sha1_object_info_extended(), that function always accesses the
packfile whenever it returns information about a packed object, since it
needs to populate "u.packed".

Add the ability to pass NULL, and use NULL-ness of the argument to
activate an optimization in which sha1_object_info_extended() does not
needlessly access the packfile. A subsequent patch will make use of this
optimization.

A similar optimization is not made for the cached and loose cases as it
would not cause a significant performance improvement.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jonathan Tan 2017-06-21 17:40:23 -07:00 коммит произвёл Junio C Hamano
Родитель dfdd4afcf9
Коммит cd585e2a33
1 изменённых файлов: 11 добавлений и 0 удалений

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@ -2977,12 +2977,16 @@ static int sha1_loose_object_info(const unsigned char *sha1,
int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
{
static struct object_info blank_oi = OBJECT_INFO_INIT;
struct pack_entry e;
int rtype;
const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
lookup_replace_object(sha1) :
sha1;
if (!oi)
oi = &blank_oi;
if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
struct cached_object *co = find_cached_object(real);
if (co) {
@ -3020,6 +3024,13 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
}
}
if (oi == &blank_oi)
/*
* We know that the caller doesn't actually need the
* information below, so return early.
*/
return 0;
rtype = packed_object_info(e.p, e.offset, oi);
if (rtype < 0) {
mark_bad_packed_object(e.p, real);