diff.c: don't add extra '/' to pathname
[git/git.git] / cache.h
1 #ifndef CACHE_H
2 #define CACHE_H
3
4 #include <unistd.h>
5 #include <stdio.h>
6 #include <sys/stat.h>
7 #include <fcntl.h>
8 #include <stddef.h>
9 #include <stdlib.h>
10 #include <stdarg.h>
11 #include <string.h>
12 #include <errno.h>
13 #include <sys/mman.h>
14 #include <sys/param.h>
15 #include <netinet/in.h>
16
17 #include SHA1_HEADER
18 #include <zlib.h>
19
20 /*
21 * Basic data structures for the directory cache
22 *
23 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
24 * not even trying to be portable. It's trying to be efficient. It's
25 * just a cache, after all.
26 */
27
28 #define CACHE_SIGNATURE 0x44495243 /* "DIRC" */
29 struct cache_header {
30 unsigned int hdr_signature;
31 unsigned int hdr_version;
32 unsigned int hdr_entries;
33 };
34
35 /*
36 * The "cache_time" is just the low 32 bits of the
37 * time. It doesn't matter if it overflows - we only
38 * check it for equality in the 32 bits we save.
39 */
40 struct cache_time {
41 unsigned int sec;
42 unsigned int nsec;
43 };
44
45 /*
46 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
47 * Again - this is just a (very strong in practice) heuristic that
48 * the inode hasn't changed.
49 *
50 * We save the fields in big-endian order to allow using the
51 * index file over NFS transparently.
52 */
53 struct cache_entry {
54 struct cache_time ce_ctime;
55 struct cache_time ce_mtime;
56 unsigned int ce_dev;
57 unsigned int ce_ino;
58 unsigned int ce_mode;
59 unsigned int ce_uid;
60 unsigned int ce_gid;
61 unsigned int ce_size;
62 unsigned char sha1[20];
63 unsigned short ce_flags;
64 char name[0];
65 };
66
67 #define CE_NAMEMASK (0x0fff)
68 #define CE_STAGEMASK (0x3000)
69 #define CE_STAGESHIFT 12
70
71 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
72 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
73 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
74 #define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
75
76 #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
77 #define create_ce_mode(mode) htonl(S_IFREG | ce_permissions(mode))
78
79 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
80
81 const char *sha1_file_directory;
82 struct cache_entry **active_cache;
83 unsigned int active_nr, active_alloc;
84
85 #define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
86 #define DEFAULT_DB_ENVIRONMENT ".git/objects"
87
88 #define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
89
90 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
91 #define DEFAULT_INDEX_ENVIRONMENT ".git/index"
92
93 #define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
94
95 #define alloc_nr(x) (((x)+16)*3/2)
96
97 /* Initialize and use the cache information */
98 extern int read_cache(void);
99 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
100 extern int cache_name_pos(const char *name, int namelen);
101 extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
102 extern int remove_entry_at(int pos);
103 extern int remove_file_from_cache(char *path);
104 extern int same_name(struct cache_entry *a, struct cache_entry *b);
105 extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
106
107 #define MTIME_CHANGED 0x0001
108 #define CTIME_CHANGED 0x0002
109 #define OWNER_CHANGED 0x0004
110 #define MODE_CHANGED 0x0008
111 #define INODE_CHANGED 0x0010
112 #define DATA_CHANGED 0x0020
113
114 /* Return a statically allocated filename matching the sha1 signature */
115 extern char *sha1_file_name(const unsigned char *sha1);
116
117 /* Write a memory buffer out to the sha file */
118 extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
119
120 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
121 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
122 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
123 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
124 extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
125
126 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
127
128 /* Read a tree into the cache */
129 extern int read_tree(void *buffer, unsigned long size, int stage);
130
131 extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
132
133 extern int has_sha1_file(const unsigned char *sha1);
134
135 /* Convert to/from hex/sha1 representation */
136 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
137 extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
138
139 /* General helper functions */
140 extern void usage(const char *err);
141 extern void die(const char *err, ...);
142 extern int error(const char *err, ...);
143
144 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
145
146 extern void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
147 unsigned long *size,
148 unsigned char *tree_sha1_ret);
149
150 static inline void *xmalloc(int size)
151 {
152 void *ret = malloc(size);
153 if (!ret)
154 die("Out of memory, malloc failed");
155 return ret;
156 }
157
158 static inline void *xrealloc(void *ptr, int size)
159 {
160 void *ret = realloc(ptr, size);
161 if (!ret)
162 die("Out of memory, realloc failed");
163 return ret;
164 }
165
166 #endif /* CACHE_H */