Граф коммитов

20 Коммитов

Автор SHA1 Сообщение Дата
Linus Torvalds 4c81b03e30 Make pack creation always fsync() the result
This means that we can depend on packs always being stable on disk,
simplifying a lot of the object serialization worries.  And unlike loose
objects, serializing pack creation IO isn't going to be a performance
killer.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-05-31 14:46:57 -07:00
Nicolas Pitre ec640ed1cf remove dead code from the csum-file interface
The provided name argument is always constant and valid in every
caller's context, so no need to have an array of PATH_MAX chars to copy
it into when a simple pointer will do.  Unfortunately that means getting
rid of wascally wabbits too.

The 'error' field is also unused.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-05 12:55:33 -08:00
Nicolas Pitre 218558af59 make display of total transferred more accurate
The throughput display needs a delay period before accounting and
displaying anything.  Yet it might be called after some amount of data
has already been transferred.  The display of total data is therefore
accounted late and therefore smaller than the reality.

Let's call display_throughput() with an absolute amount of transferred
data instead of a relative number, and let the throughput code find the
relative amount of data by itself as needed.  This way the displayed
total is always exact.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-05 12:53:14 -08:00
Nicolas Pitre 2a128d63dc add throughput display to git-push
This one triggers only when git-pack-objects is called with
--all-progress and --stdout which is the combination used by
git-push.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-10-30 16:08:40 -07:00
Nicolas Pitre 7ba502c47b pack-objects.c: fix some global variable abuse and memory leaks
To keep things well layered, sha1close() now returns the file descriptor
when it doesn't close the file.

An ugly cast was added to the return of write_idx_file() to avoid a
warning.  A proper fix will come separately.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-10-17 02:54:56 -04:00
Junio C Hamano 4175e9e3a8 More static
There still are quite a few symbols that ought to be static.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-13 02:02:10 -07:00
Dana L. How f02153696f Alter sha1close() 3rd argument to request flush only
update=0 suppressed writing the final SHA-1 but was not used.
Now final=0 suppresses SHA-1 finalization, SHA-1 writing,
and closing -- in other words,  only flush the buffer.

Signed-off-by: Dana L. How <danahow@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-20 21:55:26 -07:00
Dana How 960ccca680 Custom compression levels for objects and packs
Add config variables pack.compression and core.loosecompression ,
and switch --compression=level to pack-objects.

Loose objects will be compressed using core.loosecompression if set,
else core.compression if set, else Z_BEST_SPEED.
Packed objects will be compressed using --compression=level if seen,
else pack.compression if set, else core.compression if set,
else Z_DEFAULT_COMPRESSION.  This is the "pack compression level".

Loose objects added to a pack undeltified will be recompressed
to the pack compression level if it is unequal to the current
loose compression level by the preceding rules,  or if the loose
object was written while core.legacyheaders = true.  Newly
deltified loose objects are always compressed to the current
pack compression level.

Previously packed objects added to a pack are recompressed
to the current pack compression level exactly when their
deltification status changes,  since the previous pack data
cannot be reused.

In either case,  the --no-reuse-object switch from the first
patch below will always force recompression to the current pack
compression level,  instead of assuming the pack compression level
hasn't changed and pack data can be reused when possible.

This applies on top of the following patches from Nicolas Pitre:
[PATCH] allow for undeltified objects not to be reused
[PATCH] make "repack -f" imply "pack-objects --no-reuse-object"

Signed-off-by: Dana L. How <danahow@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-10 15:23:09 -07:00
Nicolas Pitre 78d1e84fe5 compute a CRC32 for each object as stored in a pack
The most important optimization for performance when repacking is the
ability to reuse data from a previous pack as is and bypass any delta
or even SHA1 computation by simply copying the raw data from one pack
to another directly.

The problem with  this is that any data corruption within a copied object
would go unnoticed and the new (repacked) pack would be self-consistent
with its own checksum despite containing a corrupted object.  This is a
real issue that already happened at least once in the past.

In some attempt to prevent this, we validate the copied data by inflating
it and making sure no error is signaled by zlib.  But this is still not
perfect as a significant portion of a pack content is made of object
headers and references to delta base objects which are not deflated and
therefore not validated when repacking actually making the pack data reuse
still not as safe as it could be.

Of course a full SHA1 validation could be performed, but that implies
full data inflating and delta replaying which is extremely costly, which
cost the data reuse optimization was designed to avoid in the first place.

So the best solution to this is simply to store a CRC32 of the raw pack
data for each object in the pack index.  This way any object in a pack can
be validated before being copied as is in another pack, including header
and any other non deflated data.

Why CRC32 instead of a faster checksum like Adler32?  Quoting Wikipedia:

   Jonathan Stone discovered in 2001 that Adler-32 has a weakness for very
   short messages. He wrote "Briefly, the problem is that, for very short
   packets, Adler32 is guaranteed to give poor coverage of the available
   bits. Don't take my word for it, ask Mark Adler. :-)" The problem is
   that sum A does not wrap for short messages. The maximum value of A for
   a 128-byte message is 32640, which is below the value 65521 used by the
   modulo operation. An extended explanation can be found in RFC 3309,
   which mandates the use of CRC32 instead of Adler-32 for SCTP, the
   Stream Control Transmission Protocol.

In the context of a GIT pack, we have lots of small objects, especially
deltas, which are likely to be quite small and in a size range for which
Adler32 is dimed not to be sufficient.  Another advantage of CRC32 is the
possibility for recovery from certain types of small corruptions like
single bit errors which are the most probable type of corruptions.

OK what this patch does is to compute the CRC32 of each object written to
a pack within pack-objects.  It is not written to the index yet and it is
obviously not validated when reusing pack data yet either.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-04-10 12:48:14 -07:00
Shawn Pearce e702496e43 Convert memcpy(a,b,20) to hashcpy(a,b).
This abstracts away the size of the hash values when copying them
from memory location to memory location, much as the introduction
of hashcmp abstracted away hash value comparsion.

A few call sites were using char* rather than unsigned char* so
I added the cast rather than open hashcpy to be void*.  This is a
reasonable tradeoff as most call sites already use unsigned char*
and the existing hashcmp is also declared to be unsigned char*.

[jc: Splitted the patch to "master" part, to be followed by a
 patch for merge-recursive.c which is not in "master" yet.

 Fixed the cast in the latter hunk to combine-diff.c which was
 wrong in the original.

 Also converted ones left-over in combine-diff.c, diff-lib.c and
 upload-pack.c ]

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-23 13:53:10 -07:00
David Rientjes 78b713a1d0 Make sha1flush void and remove conditional return.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-14 19:01:00 -07:00
Joachim B Haga 12f6c308d5 Make zlib compression level configurable, and change default.
With the change in default, "git add ." on kernel dir is about
twice as fast as before, with only minimal (0.5%) change in
object size. The speed difference is even more noticeable
when committing large files, which is now up to 8 times faster.

The configurability is through setting core.compression = [-1..9]
which maps to the zlib constants; -1 is the default, 0 is no
compression, and 1..9 are various speed/size tradeoffs, 9
being slowest.

Signed-off-by: Joachim B Haga (cjhaga@fys.uio.no)
Acked-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-07-03 13:55:11 -07:00
Florian Forster 1d7f171c3a Remove all void-pointer arithmetic.
ANSI C99 doesn't allow void-pointer arithmetic. This patch fixes this in
various ways. Usually the strategy that required the least changes was used.

Signed-off-by: Florian Forster <octo@verplant.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-20 01:59:46 -07:00
Junio C Hamano 1c15afb934 xread/xwrite: do not worry about EINTR at calling sites.
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>
2005-12-19 18:28:16 -08:00
Sergey Vlasov 7bf058f008 [PATCH] Plug memory leak in sha1close()
sha1create() and sha1fd() malloc the returned struct sha1file;
sha1close() should free it.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-08-08 22:51:46 -07:00
Junio C Hamano f312de018b [PATCH] Let umask do its work upon filesystem object creation.
IIRC our strategy was to let the users' umask take care of the
final mode bits.  This patch fixes places that deviate from it.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-06 10:39:59 -07:00
Linus Torvalds 4397f0148a csum-file: add "sha1fd()" to create a SHA1 csum file from an existing file descriptor
We'll use this soon to write pack-files to stdout.
2005-06-28 11:10:06 -07:00
Linus Torvalds 2700628e64 csum-file: fix missing buf pointer update
This would create broken pack archives for anything nontrivial.
2005-06-27 17:02:56 -07:00
Linus Torvalds e18088451d csum-file interface updates: return resulting SHA1
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.
2005-06-26 22:01:46 -07:00
Linus Torvalds c38138cd78 git-pack-objects: write the pack files with a SHA1 csum
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.
2005-06-26 20:27:56 -07:00