pack.h

   1 #ifndef PACK_H
   2 #define PACK_H
   3
   4 #include "object.h"
   5 #include "csum-file.h"
   6
   7 struct 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))
  15 struct 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
  40 struct 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
  58 extern void reset_pack_idx_option(struct pack_idx_option *);
  59
  60 /*
  61  * Packed object index header
  62  */
  63 struct 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  */
  71 struct pack_idx_entry {
  72         struct object_id oid;
  73         uint32_t crc32;
  74         off_t offset;
  75 };
  76
  77
  78 struct progress;
  79 /* Note, the data argument could be NULL if object type is blob */
  80 typedef int (*verify_fn)(const struct object_id *, enum object_type, unsigned long, void*, int*);
  81
  82 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);
  83 extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
  84 extern int verify_pack_index(struct packed_git *);
  85 extern int verify_pack(struct repository *, struct packed_git *, verify_fn fn, struct progress *, uint32_t);
  86 extern off_t write_pack_header(struct hashfile *f, uint32_t);
  87 extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
  88 extern 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
  95 extern 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)
 101 extern int read_pack_header(int fd, struct pack_header *);
 102
 103 extern struct hashfile *create_tmp_packfile(char **pack_tmp_name);
 104 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[]);
 105
 106 #endif