[libgit2.git] / src / pack.h

/*
 * Copyright (C) 2009-2012 the libgit2 contributors
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

#ifndef INCLUDE_pack_h__
#define INCLUDE_pack_h__

#include "git2/oid.h"

#include "common.h"
#include "map.h"
#include "mwindow.h"
#include "odb.h"

#define GIT_PACK_FILE_MODE 0444

#define PACK_SIGNATURE 0x5041434b	/* "PACK" */
#define PACK_VERSION 2
#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
struct git_pack_header {
	uint32_t hdr_signature;
	uint32_t hdr_version;
	uint32_t hdr_entries;
};

/*
 * 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.
 *
 * 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
 * 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.
 *
 * 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" */

struct git_pack_idx_header {
	uint32_t idx_signature;
	uint32_t idx_version;
};

struct git_pack_file {
	git_mwindow_file mwf;
	git_map index_map;

	uint32_t num_objects;
	uint32_t num_bad_objects;
	git_oid *bad_object_sha1; /* array of git_oid */

	int index_version;
	git_time_t mtime;
	unsigned pack_local:1, pack_keep:1, has_cache:1;
	git_oid sha1;
	git_vector cache;
	git_oid **oids;

	/* something like ".git/objects/pack/xxxxx.pack" */
	char pack_name[GIT_FLEX_ARRAY]; /* more */
};

struct git_pack_entry {
	git_off_t offset;
	git_oid sha1;
	struct git_pack_file *p;
};

int git_packfile_unpack_header(
		size_t *size_p,
		git_otype *type_p,
		git_mwindow_file *mwf,
		git_mwindow **w_curs,
		git_off_t *curpos);

int git_packfile_unpack(git_rawobj *obj, struct git_pack_file *p, git_off_t *obj_offset);
int packfile_unpack_compressed(
	git_rawobj *obj,
	struct git_pack_file *p,
	git_mwindow **w_curs,
	git_off_t *curpos,
	size_t size,
	git_otype type);

git_off_t get_delta_base(struct git_pack_file *p, git_mwindow **w_curs,
		git_off_t *curpos, git_otype type,
		git_off_t delta_obj_offset);

void packfile_free(struct git_pack_file *p);
int git_packfile_check(struct git_pack_file **pack_out, const char *path);
int git_pack_entry_find(
		struct git_pack_entry *e,
		struct git_pack_file *p,
		const git_oid *short_oid,
		size_t len);
int git_pack_foreach_entry(
		struct git_pack_file *p,
		int (*cb)(git_oid *oid, void *data),
		void *data);

#endif
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2009-2012 the libgit2 contributors
	3	*
	4	* This file is part of libgit2, distributed under the GNU GPL v2 with
	5	* a Linking Exception. For full terms see the included COPYING file.
	6	*/
	7
	8	#ifndef INCLUDE_pack_h__
	9	#define INCLUDE_pack_h__
	10
	11	#include "git2/oid.h"
	12
	13	#include "common.h"
	14	#include "map.h"
	15	#include "mwindow.h"
	16	#include "odb.h"
	17
	18	#define GIT_PACK_FILE_MODE 0444
	19
	20	#define PACK_SIGNATURE 0x5041434b /* "PACK" */
	21	#define PACK_VERSION 2
	22	#define pack_version_ok(v) ((v) == htonl(2) \|\| (v) == htonl(3))
	23	struct git_pack_header {
	24	uint32_t hdr_signature;
	25	uint32_t hdr_version;
	26	uint32_t hdr_entries;
	27	};
	28
	29	/*
	30	* The first four bytes of index formats later than version 1 should
	31	* start with this signature, as all older git binaries would find this
	32	* value illegal and abort reading the file.
	33	*
	34	* This is the case because the number of objects in a packfile
	35	* cannot exceed 1,431,660,000 as every object would need at least
	36	* 3 bytes of data and the overall packfile cannot exceed 4 GiB with
	37	* version 1 of the index file due to the offsets limited to 32 bits.
	38	* Clearly the signature exceeds this maximum.
	39	*
	40	* Very old git binaries will also compare the first 4 bytes to the
	41	* next 4 bytes in the index and abort with a "non-monotonic index"
	42	* error if the second 4 byte word is smaller than the first 4
	43	* byte word. This would be true in the proposed future index
	44	* format as idx_signature would be greater than idx_version.
	45	*/
	46
	47	#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
	48
	49	struct git_pack_idx_header {
	50	uint32_t idx_signature;
	51	uint32_t idx_version;
	52	};
	53
	54	struct git_pack_file {
	55	git_mwindow_file mwf;
	56	git_map index_map;
	57
	58	uint32_t num_objects;
	59	uint32_t num_bad_objects;
	60	git_oid bad_object_sha1; / array of git_oid */
	61
	62	int index_version;
	63	git_time_t mtime;
	64	unsigned pack_local:1, pack_keep:1, has_cache:1;
	65	git_oid sha1;
	66	git_vector cache;
	67	git_oid **oids;
	68
	69	/* something like ".git/objects/pack/xxxxx.pack" */
	70	char pack_name[GIT_FLEX_ARRAY]; /* more */
	71	};
	72
	73	struct git_pack_entry {
	74	git_off_t offset;
	75	git_oid sha1;
	76	struct git_pack_file *p;
	77	};
	78
	79	int git_packfile_unpack_header(
	80	size_t *size_p,
	81	git_otype *type_p,
	82	git_mwindow_file *mwf,
	83	git_mwindow **w_curs,
	84	git_off_t *curpos);
	85
	86	int git_packfile_unpack(git_rawobj obj, struct git_pack_file p, git_off_t *obj_offset);
	87	int packfile_unpack_compressed(
	88	git_rawobj *obj,
	89	struct git_pack_file *p,
	90	git_mwindow **w_curs,
	91	git_off_t *curpos,
	92	size_t size,
	93	git_otype type);
	94
	95	git_off_t get_delta_base(struct git_pack_file p, git_mwindow *w_curs,
	96	git_off_t *curpos, git_otype type,
	97	git_off_t delta_obj_offset);
	98
	99	void packfile_free(struct git_pack_file *p);
	100	int git_packfile_check(struct git_pack_file *pack_out, const char path);
	101	int git_pack_entry_find(
	102	struct git_pack_entry *e,
	103	struct git_pack_file *p,
	104	const git_oid *short_oid,
	105	size_t len);
	106	int git_pack_foreach_entry(
	107	struct git_pack_file *p,
	108	int (cb)(git_oid oid, void *data),
	109	void *data);
	110
	111	#endif