pack.h

   1 #ifndef PACK_H
   2 #define PACK_H
   3
   4 #include "object.h"
   5 #include "csum-file.h"
   6
   7 struct packed_git;
   8 struct pack_window;
   9 struct repository;
  10
  11 /*
  12  * Packed object header
  13  */
  14 #define PACK_SIGNATURE 0x5041434b       /* "PACK" */
  15 #define PACK_VERSION 2
  16 #define pack_version_ok(v) pack_version_ok_native(ntohl(v))
  17 #define pack_version_ok_native(v) ((v) == 2 || (v) == 3)
  18 struct pack_header {
  19         uint32_t hdr_signature;
  20         uint32_t hdr_version;
  21         uint32_t hdr_entries;
  22 };
  23
  24 /*
  25  * The first four bytes of index formats later than version 1 should
  26  * start with this signature, as all older git binaries would find this
  27  * value illegal and abort reading the file.
  28  *
  29  * This is the case because the number of objects in a packfile
  30  * cannot exceed 1,431,660,000 as every object would need at least
  31  * 3 bytes of data and the overall packfile cannot exceed 4 GiB with
  32  * version 1 of the index file due to the offsets limited to 32 bits.
  33  * Clearly the signature exceeds this maximum.
  34  *
  35  * Very old git binaries will also compare the first 4 bytes to the
  36  * next 4 bytes in the index and abort with a "non-monotonic index"
  37  * error if the second 4 byte word is smaller than the first 4
  38  * byte word.  This would be true in the proposed future index
  39  * format as idx_signature would be greater than idx_version.
  40  */
  41 #define PACK_IDX_SIGNATURE 0xff744f63   /* "\377tOc" */
  42
  43 struct pack_idx_option {
  44         unsigned flags;
  45         /* flag bits */
  46 #define WRITE_IDX_VERIFY 01 /* verify only, do not write the idx file */
  47 #define WRITE_IDX_STRICT 02
  48 #define WRITE_REV 04
  49 #define WRITE_REV_VERIFY 010
  50 #define WRITE_MTIMES 020
  51
  52         uint32_t version;
  53         uint32_t off32_limit;
  54
  55         /*
  56          * List of offsets that would fit within off32_limit but
  57          * need to be written out as 64-bit entity for byte-for-byte
  58          * verification.
  59          */
  60         int anomaly_alloc, anomaly_nr;
  61         uint32_t *anomaly;
  62
  63         size_t delta_base_cache_limit;
  64 };
  65
  66 void reset_pack_idx_option(struct pack_idx_option *);
  67
  68 /*
  69  * Packed object index header
  70  */
  71 struct pack_idx_header {
  72         uint32_t idx_signature;
  73         uint32_t idx_version;
  74 };
  75
  76 /*
  77  * Common part of object structure used for write_idx_file
  78  */
  79 struct pack_idx_entry {
  80         struct object_id oid;
  81         uint32_t crc32;
  82         off_t offset;
  83 };
  84
  85
  86 struct progress;
  87 /* Note, the data argument could be NULL if object type is blob */
  88 typedef int (*verify_fn)(const struct object_id *, enum object_type, unsigned long, void*, int*);
  89
  90 const char *write_idx_file(struct repository *repo,
  91                            const char *index_name,
  92                            struct pack_idx_entry **objects,
  93                            int nr_objects,
  94                            const struct pack_idx_option *,
  95                            const unsigned char *sha1);
  96 int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
  97 int verify_pack_index(struct packed_git *);
  98 int verify_pack(struct repository *, struct packed_git *, verify_fn fn, struct progress *, uint32_t);
  99 off_t write_pack_header(struct hashfile *f, uint32_t);
 100 void fixup_pack_header_footer(const struct git_hash_algo *, int,
 101                               unsigned char *, const char *, uint32_t,
 102                               unsigned char *, off_t);
 103 char *index_pack_lockfile(struct repository *r, int fd, int *is_well_formed);
 104
 105 struct ref;
 106
 107 void write_promisor_file(const char *promisor_name, struct ref **sought, int nr_sought);
 108
 109 char *write_rev_file(struct repository *repo,
 110                      const char *rev_name,
 111                      struct pack_idx_entry **objects,
 112                      uint32_t nr_objects,
 113                      const unsigned char *hash,
 114                      unsigned flags);
 115 char *write_rev_file_order(struct repository *repo,
 116                            const char *rev_name,
 117                            uint32_t *pack_order,
 118                            uint32_t nr_objects,
 119                            const unsigned char *hash,
 120                            unsigned flags);
 121
 122 /*
 123  * The "hdr" output buffer should be at least this big, which will handle sizes
 124  * up to 2^67.
 125  */
 126 #define MAX_PACK_OBJECT_HEADER 10
 127 int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
 128                                  enum object_type, uintmax_t);
 129
 130 #define PH_ERROR_EOF            (-1)
 131 #define PH_ERROR_PACK_SIGNATURE (-2)
 132 #define PH_ERROR_PROTOCOL       (-3)
 133 int read_pack_header(int fd, struct pack_header *);
 134
 135 struct packing_data;
 136
 137 struct hashfile *create_tmp_packfile(struct repository *repo,
 138                                      char **pack_tmp_name);
 139 void stage_tmp_packfiles(struct repository *repo,
 140                          struct strbuf *name_buffer,
 141                          const char *pack_tmp_name,
 142                          struct pack_idx_entry **written_list,
 143                          uint32_t nr_written,
 144                          struct packing_data *to_pack,
 145                          struct pack_idx_option *pack_idx_opts,
 146                          unsigned char hash[],
 147                          char **idx_tmp_name);
 148 void rename_tmp_packfile_idx(struct strbuf *basename,
 149                              char **idx_tmp_name);
 150
 151 #endif