Andrew's git - gitweb.git/blob

   1#ifndef PACK_H
   2#define PACK_H
   3
   4#include "object.h"
   5#include "csum-file.h"
   6
   7struct repository;
   8
   9/*
  10 * Packed object header
  11 */
  12#define PACK_SIGNATURE 0x5041434b       /* "PACK" */
  13#define PACK_VERSION 2
  14#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
  15struct pack_header {
  16        uint32_t hdr_signature;
  17        uint32_t hdr_version;
  18        uint32_t hdr_entries;
  19};
  20
  21/*
  22 * The first four bytes of index formats later than version 1 should
  23 * start with this signature, as all older git binaries would find this
  24 * value illegal and abort reading the file.
  25 *
  26 * This is the case because the number of objects in a packfile
  27 * cannot exceed 1,431,660,000 as every object would need at least
  28 * 3 bytes of data and the overall packfile cannot exceed 4 GiB with
  29 * version 1 of the index file due to the offsets limited to 32 bits.
  30 * Clearly the signature exceeds this maximum.
  31 *
  32 * Very old git binaries will also compare the first 4 bytes to the
  33 * next 4 bytes in the index and abort with a "non-monotonic index"
  34 * error if the second 4 byte word is smaller than the first 4
  35 * byte word.  This would be true in the proposed future index
  36 * format as idx_signature would be greater than idx_version.
  37 */
  38#define PACK_IDX_SIGNATURE 0xff744f63   /* "\377tOc" */
  39
  40struct pack_idx_option {
  41        unsigned flags;
  42        /* flag bits */
  43#define WRITE_IDX_VERIFY 01 /* verify only, do not write the idx file */
  44#define WRITE_IDX_STRICT 02
  45
  46        uint32_t version;
  47        uint32_t off32_limit;
  48
  49        /*
  50         * List of offsets that would fit within off32_limit but
  51         * need to be written out as 64-bit entity for byte-for-byte
  52         * verification.
  53         */
  54        int anomaly_alloc, anomaly_nr;
  55        uint32_t *anomaly;
  56};
  57
  58extern void reset_pack_idx_option(struct pack_idx_option *);
  59
  60/*
  61 * Packed object index header
  62 */
  63struct pack_idx_header {
  64        uint32_t idx_signature;
  65        uint32_t idx_version;
  66};
  67
  68/*
  69 * Common part of object structure used for write_idx_file
  70 */
  71struct pack_idx_entry {
  72        struct object_id oid;
  73        uint32_t crc32;
  74        off_t offset;
  75};
  76
  77
  78struct progress;
  79/* Note, the data argument could be NULL if object type is blob */
  80typedef int (*verify_fn)(const struct object_id *, enum object_type, unsigned long, void*, int*);
  81
  82extern 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);
  83extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
  84extern int verify_pack_index(struct packed_git *);
  85extern int verify_pack(struct repository *, struct packed_git *, verify_fn fn, struct progress *, uint32_t);
  86extern off_t write_pack_header(struct hashfile *f, uint32_t);
  87extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
  88extern char *index_pack_lockfile(int fd);
  89
  90/*
  91 * The "hdr" output buffer should be at least this big, which will handle sizes
  92 * up to 2^67.
  93 */
  94#define MAX_PACK_OBJECT_HEADER 10
  95extern int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
  96                                        enum object_type, uintmax_t);
  97
  98#define PH_ERROR_EOF            (-1)
  99#define PH_ERROR_PACK_SIGNATURE (-2)
 100#define PH_ERROR_PROTOCOL       (-3)
 101extern int read_pack_header(int fd, struct pack_header *);
 102
 103extern struct hashfile *create_tmp_packfile(char **pack_tmp_name);
 104extern 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[]);
 105
 106#endif