create_tmp_packfile(): a helper function
[git/git.git] / pack.h
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1#ifndef PACK_H
2#define PACK_H
3
1974632c 4#include "object.h"
c0ad4657 5#include "csum-file.h"
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6
7/*
8 * Packed object header
9 */
10#define PACK_SIGNATURE 0x5041434b /* "PACK" */
29f049a0 11#define PACK_VERSION 2
d60fc1c8 12#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
a733cb60 13struct pack_header {
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14 uint32_t hdr_signature;
15 uint32_t hdr_version;
16 uint32_t hdr_entries;
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17};
18
df1b059d 19/*
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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.
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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
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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.
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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
ebcfb379 38struct pack_idx_option {
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39 unsigned flags;
40 /* flag bits */
41#define WRITE_IDX_VERIFY 01
42
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43 uint32_t version;
44 uint32_t off32_limit;
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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;
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53};
54
55extern void reset_pack_idx_option(struct pack_idx_option *);
aa7e44bf 56
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57/*
58 * Packed object index header
59 */
60struct pack_idx_header {
61 uint32_t idx_signature;
62 uint32_t idx_version;
63};
64
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65/*
66 * Common part of object structure used for write_idx_file
67 */
68struct pack_idx_entry {
69 unsigned char sha1[20];
70 uint32_t crc32;
71 off_t offset;
72};
73
ebcfb379 74extern 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);
c41a4a94 75extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
9b0aa728 76extern int verify_pack_index(struct packed_git *);
77d3ecee 77extern int verify_pack(struct packed_git *);
c0ad4657 78extern off_t write_pack_header(struct sha1file *f, uint32_t);
abeb40e5 79extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
106764e6 80extern char *index_pack_lockfile(int fd);
f965c525 81extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
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82
83#define PH_ERROR_EOF (-1)
84#define PH_ERROR_PACK_SIGNATURE (-2)
85#define PH_ERROR_PROTOCOL (-3)
86extern int read_pack_header(int fd, struct pack_header *);
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87
88extern struct sha1file *create_tmp_packfile(char **pack_tmp_name);
89
a733cb60 90#endif