Simplify show-diff cache entry name handling.
[git/git.git] / cache.h
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1#ifndef CACHE_H
2#define CACHE_H
3
4#include <stdio.h>
5#include <sys/stat.h>
6#include <fcntl.h>
7#include <stddef.h>
8#include <stdlib.h>
9#include <stdarg.h>
bf0c6e83 10#include <string.h>
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11#include <errno.h>
12#include <sys/mman.h>
ccc4feb5 13#include <netinet/in.h>
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14
15#include <openssl/sha.h>
16#include <zlib.h>
17
18/*
19 * Basic data structures for the directory cache
20 *
21 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
22 * not even trying to be portable. It's trying to be efficient. It's
23 * just a cache, after all.
24 */
25
26#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */
27struct cache_header {
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28 unsigned int hdr_signature;
29 unsigned int hdr_version;
30 unsigned int hdr_entries;
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31 unsigned char sha1[20];
32};
33
34/*
35 * The "cache_time" is just the low 32 bits of the
36 * time. It doesn't matter if it overflows - we only
37 * check it for equality in the 32 bits we save.
38 */
39struct cache_time {
40 unsigned int sec;
41 unsigned int nsec;
42};
43
44/*
45 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
46 * Again - this is just a (very strong in practice) heuristic that
47 * the inode hasn't changed.
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48 *
49 * We save the fields in big-endian order to allow using the
50 * index file over NFS transparently.
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51 */
52struct cache_entry {
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53 struct cache_time ce_ctime;
54 struct cache_time ce_mtime;
55 unsigned int ce_dev;
56 unsigned int ce_ino;
57 unsigned int ce_mode;
58 unsigned int ce_uid;
59 unsigned int ce_gid;
60 unsigned int ce_size;
e83c5163 61 unsigned char sha1[20];
ccc4feb5 62 unsigned short ce_namelen;
59c1e249 63 char name[0];
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64};
65
66const char *sha1_file_directory;
67struct cache_entry **active_cache;
68unsigned int active_nr, active_alloc;
69
70#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
4bb04f21 71#define DEFAULT_DB_ENVIRONMENT ".git/objects"
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72
73#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
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74#define ce_namelen(ce) ntohs((ce)->ce_namelen)
75#define ce_size(ce) cache_entry_size(ce_namelen(ce))
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76
77#define alloc_nr(x) (((x)+16)*3/2)
78
734aab75 79/* Initialize and use the cache information */
e83c5163 80extern int read_cache(void);
197ee8c9 81extern int write_cache(int newfd, struct cache_entry **cache, int entries);
eb38c22f 82extern int cache_name_pos(const char *name, int namelen);
121481ab 83extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
197ee8c9 84extern int remove_file_from_cache(char *path);
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85extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
86
87#define MTIME_CHANGED 0x0001
88#define CTIME_CHANGED 0x0002
89#define OWNER_CHANGED 0x0004
90#define MODE_CHANGED 0x0008
91#define INODE_CHANGED 0x0010
92#define DATA_CHANGED 0x0020
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93
94/* Return a statically allocated filename matching the sha1 signature */
73134b6d 95extern char *sha1_file_name(const unsigned char *sha1);
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96
97/* Write a memory buffer out to the sha file */
73134b6d 98extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
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99
100/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
73134b6d 101extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
2ade9340 102extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
73134b6d 103extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
d6d3f9d0 104extern int write_sha1_file(char *buf, unsigned len, unsigned char *return_sha1);
24778e33 105extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size);
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106
107/* Convert to/from hex/sha1 representation */
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108extern int get_sha1_hex(const char *hex, unsigned char *sha1);
109extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
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110
111/* General helper functions */
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112extern void usage(const char *err);
113extern void die(const char *err, ...);
114extern int error(const char *err, ...);
115
79517a06 116extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
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117
118#endif /* CACHE_H */