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