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