[PATCH] Byteorder fix for read-tree, new -m semantics version.
[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_flags;
63 char name[0];
64 };
65
66 #define CE_NAMEMASK (0x0fff)
67 #define CE_STAGEMASK (0x3000)
68
69 #define create_ce_flags(len, stage) htons((len) | ((stage) << 12))
70
71 const char *sha1_file_directory;
72 struct cache_entry **active_cache;
73 unsigned int active_nr, active_alloc;
74
75 #define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
76 #define DEFAULT_DB_ENVIRONMENT ".git/objects"
77
78 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
79 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
80 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
81
82 #define alloc_nr(x) (((x)+16)*3/2)
83
84 /* Initialize and use the cache information */
85 extern int read_cache(void);
86 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
87 extern int cache_name_pos(const char *name, int namelen);
88 extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
89 extern int remove_file_from_cache(char *path);
90 extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
91
92 #define MTIME_CHANGED 0x0001
93 #define CTIME_CHANGED 0x0002
94 #define OWNER_CHANGED 0x0004
95 #define MODE_CHANGED 0x0008
96 #define INODE_CHANGED 0x0010
97 #define DATA_CHANGED 0x0020
98
99 /* Return a statically allocated filename matching the sha1 signature */
100 extern char *sha1_file_name(const unsigned char *sha1);
101
102 /* Write a memory buffer out to the sha file */
103 extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
104
105 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
106 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
107 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
108 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
109 extern int write_sha1_file(char *buf, unsigned len, unsigned char *return_sha1);
110 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size);
111
112 /* Convert to/from hex/sha1 representation */
113 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
114 extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
115
116 /* General helper functions */
117 extern void usage(const char *err);
118 extern void die(const char *err, ...);
119 extern int error(const char *err, ...);
120
121 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
122
123 #endif /* CACHE_H */