After experimenting with code to add the ability to encode a delta
against part of the deltified file, it turns out that resulting packs
are _bigger_ than when this ability is not used. The raw delta output
might be smaller, but it doesn't compress as well using gzip with a
negative net saving on average.
Said bit would in fact be more useful to allow for encoding the copying
of chunks larger than 64KB providing more savings with large files.
This will correspond to packs version 3.
While the current code still produces packs version 2, it is made future
proof so pack versions 2 and 3 are accepted. Any pack version 2 are
compatible with version 3 since the redefined bit was never used before.
When enough time has passed, code to use that bit to produce version 3
packs could be added.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We had errno==EINTR check after read(2)/write(2) sprinkled all
over the places, always doing continue. Consolidate them into
xread()/xwrite() wrapper routines.
Credits for suggestion goes to HPA -- bugs are mine.
Signed-off-by: Junio C Hamano <junkio@cox.net>
These commands are converted to run from a subdirectory.
commit-tree convert-objects merge-base merge-index mktag
pack-objects pack-redundant prune-packed read-tree tar-tree
unpack-file unpack-objects update-server-info write-tree
Signed-off-by: Junio C Hamano <junkio@cox.net>
This patch documents the -n command-line option to git-unpack-objects,
as it was previously undocumented.
Signed-off-by: Nikolai Weibull <nikolai@bitwi.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>
- Call inflateEnd to release zlib state after use.
- After resolving delta, free base object data.
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We used to print the index of the object we unpacked, not how many we
had unpacked. Which caused slightly confusing progress reports like
100% (2/3) done
rather than the more obvious "3/3" for 100% ;)
This ends up being very calming for big "git clone"s, since otherwise
you just get very frustrated with a long silence, wondering whether it's
working at all.
Use "-q" to quiet it down.
Now if we could just do the same for the initial "figure out what to
pack" phase, which can also be quite slow if the other end is busy (or
not packed and not in cache)...
zlib actually writes a header for that case, and while ignoring that
header will get us the right data, it will also end up messing up our
stream position. So we actually want zlib to "uncompress" even an empty
object.
It can no longer be as verbose, since it doesn't have a good way to
resolve deltas (now that it is purely streaming, it cannot seek around
to read the objects a delta is based on).
But it can check that the thing unpacks cleanly at least as far as pack
syntax goes - all the objects uncompress cleanly, and the pack has the
right final SHA1.
I'd like to add back the "dry-run" thing, but it turns out that to do it
well, I'd have to keep all the object data in memory (which is not
acceptable). So I'll clean it up a bit and make it do as many checks as
it can.
This makes it match the new delta encoding, and admittedly makes the
code easier to follow.
This also updates the PACK file version to 2, since this (and the delta
encoding change in the previous commit) are incompatible with the old
format.
It gets a bit more complicated to unpack in a streaming environment, but
here it is. The rewrite is actually a lot cleaner in other ways, it's
just a bit more subtle.
Standalone unpack-objects command was not adjusted for header length
encoding change when dealing with deltified entry. This fixes it.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This also adds a header with a signature, version info, and the number
of objects to the pack file. It also encodes the file length and type
more efficiently.
Also, make the writing of the SHA1 as a end-header be conditional: not
every user will necessarily want to write the SHA1 to the file itself,
even though current users do (but we migh end up using the same helper
functions for the object files themselves, that don't do this).
This also makes the packed index file contain the SHA1 of the packed
data file at the end (just before its own SHA1). That way you can
validate the pairing of the two if you want to.
We want to be able to check their integrity later, and putting the
sha1-sum of the contents at the end is a good thing. The writing
routines are generic, so we could try to re-use them for the index file,
instead of having the same logic duplicated.
Update unpack-objects to know about the extra 20 bytes at the end
of the index.
This actually successfully packed and unpacked a git archive down to
1.3MB (17MB unpacked).
Right now unpacking is way too noisy, lots of debug messages left.
This finishes the initial round of git-pack-object /
git-unpack-object pair. They are now good enough to be used as
a transport medium:
- Fix delta direction in pack-objects; the original was
computing delta to create the base object from the object to
be squashed, which was quite unfriendly for unpacker ;-).
- Add a script to test the very basics.
- Implement unpacker for both regular and deltified objects.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
So far it just reads the header and generates the list of objects.
It also sorts them by the order they are written in the pack file,
since that ends up being the same order we got them originally, and
is thus "most recent first".
