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>
Jonathan Tan committed
Jun 21, 2017 at 17:40 UTC
cd585e2a33841d725b821adbb9b48654fc7d0b61
1 file changed
+11
sha1_file.c
+11
@@ -2977,12 +2977,16 @@ static int sha1_loose_object_info(const unsigned char *sha1,
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int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
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{
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+ static struct object_info blank_oi = OBJECT_INFO_INIT;
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struct pack_entry e;
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int rtype;
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const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
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lookup_replace_object(sha1) :
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sha1;
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+ if (!oi)
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+ oi = &blank_oi;
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+
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if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
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struct cached_object *co = find_cached_object(real);
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if (co) {
@@ -3020,6 +3024,13 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
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}
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}
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+ if (oi == &blank_oi)
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+ /*
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+ * We know that the caller doesn't actually need the
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+ * information below, so return early.
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+ */
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+ return 0;
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+
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rtype = packed_object_info(e.p, e.offset, oi);
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if (rtype < 0) {
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mark_bad_packed_object(e.p, real);