When we advertise a ref, the first thing we do is parse the
pointed-to object. This gives us two things:
1. a "struct object" we can use to store flags
2. the type of the object, so we know whether we need to
dereference it as a tag
Instead, we can just use lookup_unknown_object to get an
object struct, and then fill in just the type field using
sha1_object_info (which, in the case of packed files, can
find the information without actually inflating the object
data).
This can save time if you have a large number of refs, and
the client isn't actually going to request those refs (e.g.,
because most of them are already up-to-date).
The downside is that we are no longer verifying objects that
we advertise by fully parsing them (however, we do still
know we actually have them, because sha1_object_info must
find them to get the type). While we might fail to detect a
corrupt object here, if the client actually fetches the
object, we will parse (and verify) it then.
On a repository with 120K refs, the advertisement portion of
upload-pack goes from ~3.4s to 3.2s (the failure to speed up
more is largely due to the fact that most of these refs are
tags, which need dereferenced to find the tag destination
anyway).
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
upload-pack.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/upload-pack.c b/upload-pack.c
index 6f36f62..65cb0ff 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -720,11 +720,14 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
static const char *capabilities = "multi_ack thin-pack side-band"
" side-band-64k ofs-delta shallow no-progress"
" include-tag multi_ack_detailed";
- struct object *o = parse_object(sha1);
+ struct object *o = lookup_unknown_object(sha1);
const char *refname_nons = strip_namespace(refname);
- if (!o)
- die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
+ if (o->type == OBJ_NONE) {
+ o->type = sha1_object_info(sha1, NULL);
+ if (o->type < 0)
+ die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
+ }
if (capabilities)
packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname_nons,
@@ -738,6 +741,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
nr_our_refs++;
}
if (o->type == OBJ_TAG) {
+ o = parse_object(o->sha1);
o = deref_tag(o, refname, 0);
if (o)
packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname_nons);
--
1.7.6.5.14.g7b06f
--
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