kernel/git - git - PowerEL Git System

Commit Graph

Author	SHA1	Message	Date
Junio C Hamano	6c52614864	csum-file: introduce sha1file_checkpoint It is useful to be able to rewind a check-summed file to a certain previous state after writing data into it using sha1write() API. The fast-import command does this after streaming a blob data to the packfile being generated and then noticing that the same blob has already been written, and it does this with a private code truncate_pack() that is commented as "Yes, this is a layering violation". Introduce two API functions, sha1file_checkpoint(), that allows the caller to save a state of a sha1file, and then later revert it to the saved state. Use it to reimplement truncate_pack(). Signed-off-by: Junio C Hamano <gitster@pobox.com>	13 years ago
Junio C Hamano	e337a04de2	index-pack: --verify Given an existing .pack file and the .idx file that describes it, this new mode of operation reads and re-index the packfile and makes sure the existing .idx file matches the result byte-for-byte. All the objects in the .pack file are validated during this operation as well. Unlike verify-pack, which visits each object described in the .idx file in the SHA-1 order, index-pack efficiently exploits the delta-chain to avoid rebuilding the objects that are used as the base of deltified objects over and over again while validating the objects, resulting in much quicker verification of the .pack file and its .idx file. This version however cannot verify a .pack/.idx pair with a handcrafted v2 index that uses 64-bit offset representation for offsets that would fit within 31-bit. You can create such an .idx file by giving a custom offset to --index-version option to the command. Signed-off-by: Junio C Hamano <gitster@pobox.com>	14 years ago
Nicolas Pitre	838cd34664	fix pread()'s short read in index-pack Since v1.6.0.2~13^2~ the completion of a thin pack uses sha1write() for its ability to compute a SHA1 on the written data. This also provides data buffering which, along with commit `92392b4a45`, will confuse pread() whenever an appended object is 1) freed due to memory pressure because of the depth-first delta processing, and 2) needed again because it has many delta children, and 3) its data is still buffered by sha1write(). Let's fix the issue by simply forcing cached data out when such an object is written so it can be pread()'d at leisure. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Shawn O. Pearce <spearce@spearce.org>	16 years ago
Nicolas Pitre	9126f0091f	fix openssl headers conflicting with custom SHA1 implementations On ARM I have the following compilation errors: CC fast-import.o In file included from cache.h:8, from builtin.h:6, from fast-import.c:142: arm/sha1.h:14: error: conflicting types for 'SHA_CTX' /usr/include/openssl/sha.h:105: error: previous declaration of 'SHA_CTX' was here arm/sha1.h:16: error: conflicting types for 'SHA1_Init' /usr/include/openssl/sha.h:115: error: previous declaration of 'SHA1_Init' was here arm/sha1.h:17: error: conflicting types for 'SHA1_Update' /usr/include/openssl/sha.h:116: error: previous declaration of 'SHA1_Update' was here arm/sha1.h:18: error: conflicting types for 'SHA1_Final' /usr/include/openssl/sha.h:117: error: previous declaration of 'SHA1_Final' was here make: *** [fast-import.o] Error 1 This is because openssl header files are always included in git-compat-util.h since commit `684ec6c63c` whenever NO_OPENSSL is not set, which somehow brings in <openssl/sha1.h> clashing with the custom ARM version. Compilation of git is probably broken on PPC too for the same reason. Turns out that the only file requiring openssl/ssl.h and openssl/err.h is imap-send.c. But only moving those problematic includes there doesn't solve the issue as it also includes cache.h which brings in the conflicting local SHA1 header file. As suggested by Jeff King, the best solution is to rename our references to SHA1 functions and structure to something git specific, and define those according to the implementation used. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Shawn O. Pearce <spearce@spearce.org>	16 years ago
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>	17 years ago
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>	17 years ago
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>	17 years ago
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>	17 years ago
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>	18 years ago
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>	18 years ago
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>	18 years ago
Timo Sirainen	4ec99bf080	[PATCH] -Werror fixes GCC's format __attribute__ is good for checking errors, especially with -Wformat=2 parameter. This fixes most of the reported problems against 2005-08-09 snapshot.	20 years ago
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.	20 years ago
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.	20 years ago
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.	20 years ago

16 Commits (5594bcad21da70d2e9704cf96baa91b8d99dc27b)