Start preparing for 1.8.4.2
[alt-git.git] / pack.h
blobaa6ee7d606f1d5336bff9a3067b44057c362e788
1 #ifndef PACK_H
2 #define PACK_H
4 #include "object.h"
5 #include "csum-file.h"
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))
13 struct pack_header {
14 uint32_t hdr_signature;
15 uint32_t hdr_version;
16 uint32_t hdr_entries;
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.
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.
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.
36 #define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
38 struct 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
44 uint32_t version;
45 uint32_t off32_limit;
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.
52 int anomaly_alloc, anomaly_nr;
53 uint32_t *anomaly;
56 extern void reset_pack_idx_option(struct pack_idx_option *);
59 * Packed object index header
61 struct pack_idx_header {
62 uint32_t idx_signature;
63 uint32_t idx_version;
67 * Common part of object structure used for write_idx_file
69 struct pack_idx_entry {
70 unsigned char sha1[20];
71 uint32_t crc32;
72 off_t offset;
76 struct progress;
77 typedef int (*verify_fn)(const unsigned char*, enum object_type, unsigned long, void*, int*);
79 extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, unsigned char *sha1);
80 extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
81 extern int verify_pack_index(struct packed_git *);
82 extern int verify_pack(struct packed_git *, verify_fn fn, struct progress *, uint32_t);
83 extern off_t write_pack_header(struct sha1file *f, uint32_t);
84 extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
85 extern char *index_pack_lockfile(int fd);
86 extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
88 #define PH_ERROR_EOF (-1)
89 #define PH_ERROR_PACK_SIGNATURE (-2)
90 #define PH_ERROR_PROTOCOL (-3)
91 extern int read_pack_header(int fd, struct pack_header *);
93 extern struct sha1file *create_tmp_packfile(char **pack_tmp_name);
94 extern void finish_tmp_packfile(char *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[]);
96 #endif