When upload-pack advertises refs, it dereferences any tags
it sees, and shows the resulting sha1 to the client. It does
this by calling deref_tag. That function must load and parse
each tag object to find the sha1 of the tagged object.
However, it also ends up parsing the tagged object itself,
which is not strictly necessary for upload-pack's use.
Each tag produces two object loads (assuming it is not a
recursive tag), when it could get away with only a single
one. Dropping the second load halves the effort we spend.
The downside is that we are no longer verifying the
resulting object by loading it. In particular:
1. We never cross-check the "type" field given in the tag
object with the type of the pointed-to object. If the
tag says it points to a tag but doesn't, then we will
keep peeling and realize the error. If the tag says it
points to a non-tag but actually points to a tag, we
will stop peeling and just advertise the pointed-to
tag.
2. If we are missing the pointed-to object, we will not
realize (because we never even look it up in the object
db).
However, both of these are errors in the object database,
and both will be detected if a client actually requests the
broken objects in question. So we are simply pushing the
verification away from the advertising stage, and down to
the actual fetching stage.
On my test repo with 120K refs, this drops the time to
advertise the refs from ~3.2s to ~2.0s.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
into tag.h/c for later reuse and modification.
Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just like with committer dates, we parse the tagger date into the
struct tag so its available for further downstream processing.
However since the tagger header was not introduced until Git 0.99.1
we must consider it optional. For tags missing this header we use
the default date of 0.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Its documented as unused. So lets just drop it from the structure
since we haven't ever used it.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One caller of deref_tag() was not careful enough to make sure
what deref_tag() returned was not NULL (i.e. we found a tag
object that points at an object we do not have). Fix it, and
warn about refs that point at such an incomplete tag where
needed.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Again I left the v2.6.11-tree tag behind. My bad.
This commit makes sure that we do not barf when pushing a ref
that is a non-commitish tag. You can update a remote ref under
the following conditions:
* You can always use --force.
* Creating a brand new ref is OK.
* If the remote ref is exactly the same as what you are
pushing, it is OK (nothing is pushed).
* You can replace a commitish with another commitish which is a
descendant of it, if you can verify the ancestry between them;
this and the above means you have to have what you are replacing.
* Otherwise you cannot update; you need to use --force.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Make 'sha1' parameters const where possible
Signed-off-by: Jason McMullan <jason.mcmullan@timesys.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It turns out that parse_object() is loading and decompressing given
object to free it just before calling the specific object parsing
function which does mmap and decompress the same object again. This
patch introduces the ability to parse specific objects directly from a
memory buffer.
Without this patch, running git-fsck-cache on the kernel repositorytake:
real 0m13.006s
user 0m11.421s
sys 0m1.218s
With this patch applied:
real 0m8.060s
user 0m7.071s
sys 0m0.710s
The performance increase is significant, and this is kind of a
prerequisite for sane delta object support with fsck.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds preliminary support for tags in the library. It doesn't even
store the signature, however, let alone provide any way of checking it.
Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
