Convert the index file reading/writing to use network byte order.
[git/git.git] / cache.h
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>
10 #include <string.h>
11 #include <errno.h>
12 #include <sys/mman.h>
13 #include <netinet/in.h>
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" */
27 struct cache_header {
28 unsigned int hdr_signature;
29 unsigned int hdr_version;
30 unsigned int hdr_entries;
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 */
39 struct 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.
48 *
49 * We save the fields in big-endian order to allow using the
50 * index file over NFS transparently.
51 */
52 struct cache_entry {
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;
61 unsigned char sha1[20];
62 unsigned short ce_namelen;
63 char name[0];
64 };
65
66 const char *sha1_file_directory;
67 struct cache_entry **active_cache;
68 unsigned int active_nr, active_alloc;
69
70 #define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
71 #define DEFAULT_DB_ENVIRONMENT ".git/objects"
72
73 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
74 #define ce_namelen(ce) ntohs((ce)->ce_namelen)
75 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
76
77 #define alloc_nr(x) (((x)+16)*3/2)
78
79 /* Initialize and use the cache information */
80 extern int read_cache(void);
81 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
82 extern int cache_name_pos(const char *name, int namelen);
83 extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
84 extern int remove_file_from_cache(char *path);
85 extern 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
93
94 /* Return a statically allocated filename matching the sha1 signature */
95 extern char *sha1_file_name(const unsigned char *sha1);
96
97 /* Write a memory buffer out to the sha file */
98 extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
99
100 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
101 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
102 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
103 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
104 extern int write_sha1_file(char *buf, unsigned len, unsigned char *return_sha1);
105 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size);
106
107 /* Convert to/from hex/sha1 representation */
108 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
109 extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
110
111 /* General helper functions */
112 extern void usage(const char *err);
113 extern void die(const char *err, ...);
114 extern int error(const char *err, ...);
115
116 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
117
118 #endif /* CACHE_H */