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Change pack file format. Hopefully for the last time. 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.
2005-06-28 23:21:02 +02:00
#ifndef PACK_H
#define PACK_H
Remove TYPE_* constant macros and use object_type enums consistently. This updates the type-enumeration constants introduced to reduce the memory footprint of "struct object" to match the type bits already used in the packfile format, by removing the former (i.e. TYPE_* constant macros) and using the latter (i.e. enum object_type) throughout the code for consistency. Eventually we can stop passing around the "type strings" entirely, and this will help - no confusion about two different integer enumeration. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-07-12 05:45:31 +02:00
#include "object.h"
write_pack_header(): a helper function Factor out a small logic out of the private write_pack_file() function in builtin/pack-objects.c Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 20:40:48 +02:00
#include "csum-file.h"
Change pack file format. Hopefully for the last time. 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.
2005-06-28 23:21:02 +02:00
/*
* Packed object header
*/
#define PACK_SIGNATURE 0x5041434b /* "PACK" */
Revert "move pack creation to version 3" This reverts commit 16854571aae6302f457c5fbee41ac64669b09595. Git as recent as v1.1.6 do not understand version 3 delta. v1.2.0 is Ok and I personally would say it is old enough, but the improvement between version 2 and version 3 delta is not bit enough to justify breaking older clients. We should resurrect this later, but when we do so we shold make it conditional. Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-10-15 08:37:41 +02:00
#define PACK_VERSION 2
remove delta-against-self bit 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>
2006-02-09 23:50:04 +01:00
#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
Change pack file format. Hopefully for the last time. 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.
2005-06-28 23:21:02 +02:00
struct pack_header {
Use fixed-size integers for the on-disk pack structure. Plain integer types without a fixed size can vary between platforms. Even though all common platforms use 32-bit ints, there is no guarantee that this won't change at some point. Furthermore, specifying an integer type with explicit size makes the definition of structures more obvious. Signed-off-by: Simon 'corecode' Schubert <corecode@fs.ei.tum.de> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-17 09:07:23 +01:00
uint32_t hdr_signature;
uint32_t hdr_version;
uint32_t hdr_entries;
Change pack file format. Hopefully for the last time. 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.
2005-06-28 23:21:02 +02:00
};
Document pack .idx file format upgrade strategy. Way back when Junio developed the 64 bit index topic he came up with a means of changing the .idx file format so that older Git clients would recognize that they don't understand the file and refuse to read it, while newer clients could tell the difference between the old-style and new-style .idx files. Unfortunately this wasn't recorded anywhere. This change documents how we might go about changing the .idx file format by using a special signature in the first four bytes. Credit (and possible blame) goes completely to Junio for thinking up this technique. The change also modifies the error message of the current Git code so that users get a recommendation to upgrade their Git software should this version or later encounter a new-style .idx which it cannot process. We already do this for the .pack files, but since we usually process the .idx files first its important that these files are recognized and encourage an upgrade. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-18 02:43:57 +01:00
/*
[PATCH] clean up pack index handling a bit Especially with the new index format to come, it is more appropriate to encapsulate more into check_packed_git_idx() and assume less of the index format in struct packed_git. To that effect, the index_base is renamed to index_data with void * type so it is not used directly but other pointers initialized with it. This allows for a couple pointer cast removal, as well as providing a better generic name to grep for when adding support for new index versions or formats. And index_data is declared const too while at it. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-16 21:42:50 +01:00
* The first four bytes of index formats later than version 1 should
* start with this signature, as all older git binaries would find this
* value illegal and abort reading the file.
Document pack .idx file format upgrade strategy. Way back when Junio developed the 64 bit index topic he came up with a means of changing the .idx file format so that older Git clients would recognize that they don't understand the file and refuse to read it, while newer clients could tell the difference between the old-style and new-style .idx files. Unfortunately this wasn't recorded anywhere. This change documents how we might go about changing the .idx file format by using a special signature in the first four bytes. Credit (and possible blame) goes completely to Junio for thinking up this technique. The change also modifies the error message of the current Git code so that users get a recommendation to upgrade their Git software should this version or later encounter a new-style .idx which it cannot process. We already do this for the .pack files, but since we usually process the .idx files first its important that these files are recognized and encourage an upgrade. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-18 02:43:57 +01:00
*
* This is the case because the number of objects in a packfile
* cannot exceed 1,431,660,000 as every object would need at least
[PATCH] clean up pack index handling a bit Especially with the new index format to come, it is more appropriate to encapsulate more into check_packed_git_idx() and assume less of the index format in struct packed_git. To that effect, the index_base is renamed to index_data with void * type so it is not used directly but other pointers initialized with it. This allows for a couple pointer cast removal, as well as providing a better generic name to grep for when adding support for new index versions or formats. And index_data is declared const too while at it. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-16 21:42:50 +01:00
* 3 bytes of data and the overall packfile cannot exceed 4 GiB with
* version 1 of the index file due to the offsets limited to 32 bits.
* Clearly the signature exceeds this maximum.
Document pack .idx file format upgrade strategy. Way back when Junio developed the 64 bit index topic he came up with a means of changing the .idx file format so that older Git clients would recognize that they don't understand the file and refuse to read it, while newer clients could tell the difference between the old-style and new-style .idx files. Unfortunately this wasn't recorded anywhere. This change documents how we might go about changing the .idx file format by using a special signature in the first four bytes. Credit (and possible blame) goes completely to Junio for thinking up this technique. The change also modifies the error message of the current Git code so that users get a recommendation to upgrade their Git software should this version or later encounter a new-style .idx which it cannot process. We already do this for the .pack files, but since we usually process the .idx files first its important that these files are recognized and encourage an upgrade. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-18 02:43:57 +01:00
*
* Very old git binaries will also compare the first 4 bytes to the
* next 4 bytes in the index and abort with a "non-monotonic index"
* error if the second 4 byte word is smaller than the first 4
* byte word. This would be true in the proposed future index
* format as idx_signature would be greater than idx_version.
*/
#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
write_idx_file: introduce a struct to hold idx customization options Remove two globals, pack_idx_default version and pack_idx_off32_limit, and place them in a pack_idx_option structure. Allow callers to pass it to write_idx_file() as a parameter. Adjust all callers to the API change. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-26 00:43:25 +01:00
struct pack_idx_option {
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>
2011-02-03 02:29:01 +01:00
unsigned flags;
/* flag bits */
receive-pack, fetch-pack: reject bogus pack that records objects twice When receive-pack & fetch-pack are run and store the pack obtained over the wire to a local repository, they internally run the index-pack command with the --strict option. Make sure that we reject incoming packfile that records objects twice to avoid spreading such a damage. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-17 07:04:13 +01:00
#define WRITE_IDX_VERIFY 01 /* verify only, do not write the idx file */
#define WRITE_IDX_STRICT 02
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>
2011-02-03 02:29:01 +01:00
write_idx_file: introduce a struct to hold idx customization options Remove two globals, pack_idx_default version and pack_idx_off32_limit, and place them in a pack_idx_option structure. Allow callers to pass it to write_idx_file() as a parameter. Adjust all callers to the API change. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-26 00:43:25 +01:00
uint32_t version;
uint32_t off32_limit;
index-pack --verify: read anomalous offsets from v2 idx file A pack v2 .idx file usually records offset using 64-bit representation only when the offset does not fit within 31-bit, but you can handcraft your .idx file to record smaller offset using 64-bit, storing all zero in the upper 4-byte. By inspecting the original idx file when running index-pack --verify, encode such low offsets that do not need to be in 64-bit but are encoded using 64-bit just like the original idx file so that we can still validate the pack/idx pair by comparing the idx file recomputed with the original. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-26 01:55:26 +01:00
/*
* List of offsets that would fit within off32_limit but
* need to be written out as 64-bit entity for byte-for-byte
* verification.
*/
int anomaly_alloc, anomaly_nr;
uint32_t *anomaly;
write_idx_file: introduce a struct to hold idx customization options Remove two globals, pack_idx_default version and pack_idx_off32_limit, and place them in a pack_idx_option structure. Allow callers to pass it to write_idx_file() as a parameter. Adjust all callers to the API change. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-26 00:43:25 +01:00
};
extern void reset_pack_idx_option(struct pack_idx_option *);
Unify write_index_file functions This patch unifies the write_index_file functions in builtin-pack-objects.c and index-pack.c. As the name "index" is overloaded in git, move in the direction of using "idx" and "pack idx" when refering to the pack index. There should be no change in functionality. Signed-off-by: Geert Bosch <bosch@gnat.com> Acked-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-06-01 21:18:05 +02:00
[PATCH] clean up pack index handling a bit Especially with the new index format to come, it is more appropriate to encapsulate more into check_packed_git_idx() and assume less of the index format in struct packed_git. To that effect, the index_base is renamed to index_data with void * type so it is not used directly but other pointers initialized with it. This allows for a couple pointer cast removal, as well as providing a better generic name to grep for when adding support for new index versions or formats. And index_data is declared const too while at it. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-16 21:42:50 +01:00
/*
* Packed object index header
*/
struct pack_idx_header {
uint32_t idx_signature;
uint32_t idx_version;
};
Unify write_index_file functions This patch unifies the write_index_file functions in builtin-pack-objects.c and index-pack.c. As the name "index" is overloaded in git, move in the direction of using "idx" and "pack idx" when refering to the pack index. There should be no change in functionality. Signed-off-by: Geert Bosch <bosch@gnat.com> Acked-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-06-01 21:18:05 +02:00
/*
* Common part of object structure used for write_idx_file
*/
struct pack_idx_entry {
unsigned char sha1[20];
uint32_t crc32;
off_t offset;
};
fsck: avoid reading every object twice During verify_pack() all objects are read for SHA-1 check. Then fsck_sha1() is called on every object, which read the object again (fsck_sha1 -> parse_object -> read_sha1_file). Avoid reading an object twice, do fsck_sha1 while we have an object uncompressed data in verify_pack. On git.git, with this patch I got: $ /usr/bin/time ./git fsck >/dev/null 98.97user 0.90system 1:40.01elapsed 99%CPU (0avgtext+0avgdata 616624maxresident)k 0inputs+0outputs (0major+194186minor)pagefaults 0swaps Without it: $ /usr/bin/time ./git fsck >/dev/null 231.23user 2.35system 3:53.82elapsed 99%CPU (0avgtext+0avgdata 636688maxresident)k 0inputs+0outputs (0major+461629minor)pagefaults 0swaps Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07 03:59:25 +01:00
fsck: print progress fsck is usually a long process and it would be nice if it prints progress from time to time. Progress meter is not printed when --verbose is given because --verbose prints a lot, there's no need for "alive" indicator. Progress meter may provide "% complete" information but it would be lost anyway in the flood of text. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07 03:59:26 +01:00
struct progress;
fsck: avoid reading every object twice During verify_pack() all objects are read for SHA-1 check. Then fsck_sha1() is called on every object, which read the object again (fsck_sha1 -> parse_object -> read_sha1_file). Avoid reading an object twice, do fsck_sha1 while we have an object uncompressed data in verify_pack. On git.git, with this patch I got: $ /usr/bin/time ./git fsck >/dev/null 98.97user 0.90system 1:40.01elapsed 99%CPU (0avgtext+0avgdata 616624maxresident)k 0inputs+0outputs (0major+194186minor)pagefaults 0swaps Without it: $ /usr/bin/time ./git fsck >/dev/null 231.23user 2.35system 3:53.82elapsed 99%CPU (0avgtext+0avgdata 636688maxresident)k 0inputs+0outputs (0major+461629minor)pagefaults 0swaps Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07 03:59:25 +01:00
typedef int (*verify_fn)(const unsigned char*, enum object_type, unsigned long, void*, int*);
pack-objects: name pack files after trailer hash Our current scheme for naming packfiles is to calculate the sha1 hash of the sorted list of objects contained in the packfile. This gives us a unique name, so we are reasonably sure that two packs with the same name will contain the same objects. It does not, however, tell us that two such packs have the exact same bytes. This makes things awkward if we repack the same set of objects. Due to run-to-run variations, the bytes may not be identical (e.g., changed zlib or git versions, different source object reuse due to new packs in the repository, or even different deltas due to races during a multi-threaded delta search). In theory, this could be helpful to a program that cares that the packfile contains a certain set of objects, but does not care about the particular representation. In practice, no part of git makes use of that, and in many cases it is potentially harmful. For example, if a dumb http client fetches the .idx file, it must be sure to get the exact .pack that matches it. Similarly, a partial transfer of a .pack file cannot be safely resumed, as the actual bytes may have changed. This could also affect a local client which opened the .idx and .pack files, closes the .pack file (due to memory or file descriptor limits), and then re-opens a changed packfile. In all of these cases, git can detect the problem, as we have the sha1 of the bytes themselves in the pack trailer (which we verify on transfer), and the .idx file references the trailer from the matching packfile. But it would be simpler and more efficient to actually get the correct bytes, rather than noticing the problem and having to restart the operation. This patch simply uses the pack trailer sha1 as the pack name. It should be similarly unique, but covers the exact representation of the objects. Other parts of git should not care, as the pack name is returned by pack-objects and is essentially opaque. One test needs to be updated, because it actually corrupts a pack and expects that re-packing the corrupted bytes will use the same name. It won't anymore, but we can easily just use the name that pack-objects hands back. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-05 21:28:07 +01:00
extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, const unsigned char *sha1);
verify-pack: check packed object CRC when using index version 2 To do so, check_pack_crc() moved from builtin-pack-objects.c to pack-check.c where it is more logical to share. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-25 05:19:02 +02:00
extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
Extract verify_pack_index for reuse from verify_pack The dumb HTTP transport should verify an index is completely valid before trying to use it. That requires checking the header/footer but also checking the complete content SHA-1. All of this logic is already in the front half of verify_pack, so pull it out into a new function that can be reused. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-04-19 16:23:07 +02:00
extern int verify_pack_index(struct packed_git *);
fsck: print progress fsck is usually a long process and it would be nice if it prints progress from time to time. Progress meter is not printed when --verbose is given because --verbose prints a lot, there's no need for "alive" indicator. Progress meter may provide "% complete" information but it would be lost anyway in the flood of text. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07 03:59:26 +01:00
extern int verify_pack(struct packed_git *, verify_fn fn, struct progress *, uint32_t);
write_pack_header(): a helper function Factor out a small logic out of the private write_pack_file() function in builtin/pack-objects.c Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 20:40:48 +02:00
extern off_t write_pack_header(struct sha1file *f, uint32_t);
improve reliability of fixup_pack_header_footer() Currently, this function has the potential to read corrupted pack data from disk and give it a valid SHA1 checksum. Let's add the ability to validate SHA1 checksum of existing data along the way, including before and after any arbitrary point in the pack. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-08-29 22:07:59 +02:00
extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
Refactor index-pack "keep $sha1" handling for reuse There is a subtle (but important) linkage between receive-pack and index-pack that allows index-pack to create a packfile but protect it from being deleted by a concurrent `git repack -a -d` operation. The linkage works by having index-pack mark the newly created pack with a ".keep" file and then it passes the SHA-1 name of that new packfile to receive-pack along its stdout channel. The receive-pack process must unkeep the packfile by deleting the .keep file, but can it can only do so after all elgible refs have been updated in the receiving repository. This ensures that the packfile is either kept or its objects are reachable, preventing a concurrent repacker from deleting the packfile before it can determine that its objects are actually needed by the repository. The new builtin-fetch code needs to perform the same actions if it choose to run index-pack rather than unpack-objects, so I am moving this code out to its own function where both receive-pack and fetch-pack are able to invoke it when necessary. The caller is responsible for deleting the returned ".keep" and freeing the path if the returned path is not NULL. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-09-14 09:31:16 +02:00
extern char *index_pack_lockfile(int fd);
move encode_in_pack_object_header() to a better place Commit 1b22b6c897 made duplicated versions of encode_header() into a common version called encode_in_pack_object_header(). There is however a better location that sha1_file.c for such a function though, as sha1_file.c contains nothing related to the creation of packs, and it is quite populated already. Also the comment that was moved to the header file should really remain near the function as it covers implementation details and provides no information about the actual function interface. Signed-off-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-23 21:02:37 +01:00
extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
Refactor the pack header reading function out of receive-pack.c Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-01-23 06:55:18 +01:00
#define PH_ERROR_EOF (-1)
#define PH_ERROR_PACK_SIGNATURE (-2)
#define PH_ERROR_PROTOCOL (-3)
extern int read_pack_header(int fd, struct pack_header *);
create_tmp_packfile(): a helper function Factor out a small logic out of the private write_pack_file() function in builtin/pack-objects.c Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 20:52:14 +02:00
extern struct sha1file *create_tmp_packfile(char **pack_tmp_name);
finish_tmp_packfile():use strbuf for pathname construction The old version fixes a maximum length on the buffer, which could be a problem if one is not certain of the length of get_object_directory(). Using strbuf can avoid the protential bug. Helped-by: Michael Haggerty <mhagger@alum.mit.edu> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Sun He <sunheehnus@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-03 10:24:29 +01:00
extern void finish_tmp_packfile(struct strbuf *name_buffer, const char *pack_tmp_name, struct pack_idx_entry **written_list, uint32_t nr_written, struct pack_idx_option *pack_idx_opts, unsigned char sha1[]);
create_tmp_packfile(): a helper function Factor out a small logic out of the private write_pack_file() function in builtin/pack-objects.c Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 20:52:14 +02:00
Change pack file format. Hopefully for the last time. 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.
2005-06-28 23:21:02 +02:00
#endif
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