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/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* 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 "common.h"
#include "git2/oid.h"
#include "array.h"
#include "map.h"
#include "mwindow.h"
#include "odb.h"
#include "offmap.h"
#include "oidmap.h"
#include "zstream.h"
#include "oid.h"
/**
* Function type for callbacks from git_pack_foreach_entry_offset.
*/
typedef int git_pack_foreach_entry_offset_cb(
const git_oid *id,
off64_t offset,
void *payload);
#define GIT_PACK_FILE_MODE 0444
#define PACK_SIGNATURE 0x5041434b /* "PACK" */
#define PACK_VERSION 2
#define pack_version_ok(v) ((v) == htonl(2))
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;
};
typedef struct git_pack_cache_entry {
size_t last_usage; /* enough? */
git_atomic32 refcount;
git_rawobj raw;
} git_pack_cache_entry;
struct pack_chain_elem {
off64_t base_key;
off64_t offset;
size_t size;
git_object_t type;
};
typedef git_array_t(struct pack_chain_elem) git_dependency_chain;
#define GIT_PACK_CACHE_MEMORY_LIMIT 16 * 1024 * 1024
#define GIT_PACK_CACHE_SIZE_LIMIT 1024 * 1024 /* don't bother caching anything over 1MB */
typedef struct {
size_t memory_used;
size_t memory_limit;
size_t use_ctr;
git_mutex lock;
git_offmap *entries;
} git_pack_cache;
struct git_pack_file {
git_mwindow_file mwf;
git_map index_map;
git_mutex lock; /* protect updates to index_map */
git_atomic32 refcount;
uint32_t num_objects;
uint32_t num_bad_objects;
git_oid *bad_object_ids; /* array of git_oid */
git_oid_t oid_type;
unsigned oid_hexsize:7,
oid_size:6,
pack_local:1,
pack_keep:1,
has_cache:1;
int index_version;
git_time_t mtime;
git_oidmap *idx_cache;
unsigned char **ids;
git_pack_cache bases; /* delta base cache */
time_t last_freshen; /* last time the packfile was freshened */
/* something like ".git/objects/pack/xxxxx.pack" */
char pack_name[GIT_FLEX_ARRAY]; /* more */
};
/**
* Return the position where an OID (or a prefix) would be inserted within
* the OID Lookup Table of an .idx file. This performs binary search
* between the lo and hi indices.
*
* The stride parameter is provided because .idx files version 1 store the
* OIDs interleaved with the 4-byte file offsets of the objects within the
* .pack file (stride = oid_size + 4), whereas files with version 2 store
* them in a contiguous flat array (stride = oid_size).
*/
int git_pack__lookup_id(
const void *id_lookup_table,
size_t stride,
unsigned lo,
unsigned hi,
const unsigned char *id_prefix,
const git_oid_t oid_type);
struct git_pack_entry {
off64_t offset;
git_oid id;
struct git_pack_file *p;
};
typedef struct git_packfile_stream {
off64_t curpos;
int done;
git_zstream zstream;
struct git_pack_file *p;
git_mwindow *mw;
} git_packfile_stream;
int git_packfile__object_header(size_t *out, unsigned char *hdr, size_t size, git_object_t type);
int git_packfile__name(char **out, const char *path);
int git_packfile_unpack_header(
size_t *size_p,
git_object_t *type_p,
struct git_pack_file *p,
git_mwindow **w_curs,
off64_t *curpos);
int git_packfile_resolve_header(
size_t *size_p,
git_object_t *type_p,
struct git_pack_file *p,
off64_t offset);
int git_packfile_unpack(git_rawobj *obj, struct git_pack_file *p, off64_t *obj_offset);
int git_packfile_stream_open(git_packfile_stream *obj, struct git_pack_file *p, off64_t curpos);
ssize_t git_packfile_stream_read(git_packfile_stream *obj, void *buffer, size_t len);
void git_packfile_stream_dispose(git_packfile_stream *obj);
int get_delta_base(
off64_t *delta_base_out,
struct git_pack_file *p,
git_mwindow **w_curs,
off64_t *curpos,
git_object_t type,
off64_t delta_obj_offset);
void git_packfile_free(struct git_pack_file *p, bool unlink_packfile);
int git_packfile_alloc(
struct git_pack_file **pack_out,
const char *path,
git_oid_t oid_type);
int git_pack_entry_find(
struct git_pack_entry *e,
struct git_pack_file *p,
const git_oid *short_id,
size_t len);
int git_pack_foreach_entry(
struct git_pack_file *p,
git_odb_foreach_cb cb,
void *data);
/**
* Similar to git_pack_foreach_entry, but:
* - It also provides the offset of the object within the
* packfile.
* - It does not sort the objects in any order.
* - It retains the lock while invoking the callback.
*/
int git_pack_foreach_entry_offset(
struct git_pack_file *p,
git_pack_foreach_entry_offset_cb cb,
void *data);
#endif
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