create_tmp_packfile(): a helper function
[git/git.git] / pack.h
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))
13 struct 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
38 struct pack_idx_option {
39 unsigned flags;
40 /* flag bits */
41 #define WRITE_IDX_VERIFY 01
42
43 uint32_t version;
44 uint32_t off32_limit;
45
46 /*
47 * List of offsets that would fit within off32_limit but
48 * need to be written out as 64-bit entity for byte-for-byte
49 * verification.
50 */
51 int anomaly_alloc, anomaly_nr;
52 uint32_t *anomaly;
53 };
54
55 extern void reset_pack_idx_option(struct pack_idx_option *);
56
57 /*
58 * Packed object index header
59 */
60 struct pack_idx_header {
61 uint32_t idx_signature;
62 uint32_t idx_version;
63 };
64
65 /*
66 * Common part of object structure used for write_idx_file
67 */
68 struct pack_idx_entry {
69 unsigned char sha1[20];
70 uint32_t crc32;
71 off_t offset;
72 };
73
74 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);
75 extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
76 extern int verify_pack_index(struct packed_git *);
77 extern int verify_pack(struct packed_git *);
78 extern off_t write_pack_header(struct sha1file *f, uint32_t);
79 extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
80 extern char *index_pack_lockfile(int fd);
81 extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
82
83 #define PH_ERROR_EOF (-1)
84 #define PH_ERROR_PACK_SIGNATURE (-2)
85 #define PH_ERROR_PROTOCOL (-3)
86 extern int read_pack_header(int fd, struct pack_header *);
87
88 extern struct sha1file *create_tmp_packfile(char **pack_tmp_name);
89
90 #endif