a10243d192f5444a58a056ef5a21a4386af26fb3
1#ifndef CACHE_H
2#define CACHE_H
3#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#include SHA1_HEADER
18#include <zlib.h>
19#if ZLIB_VERNUM < 0x1200
21#define deflateBound(c,s) ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
22#endif
23/*
25 * Basic data structures for the directory cache
26 *
27 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
28 * not even trying to be portable. It's trying to be efficient. It's
29 * just a cache, after all.
30 */
31#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */
33struct cache_header {
34 unsigned int hdr_signature;
35 unsigned int hdr_version;
36 unsigned int hdr_entries;
37};
38/*
40 * The "cache_time" is just the low 32 bits of the
41 * time. It doesn't matter if it overflows - we only
42 * check it for equality in the 32 bits we save.
43 */
44struct cache_time {
45 unsigned int sec;
46 unsigned int nsec;
47};
48/*
50 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
51 * Again - this is just a (very strong in practice) heuristic that
52 * the inode hasn't changed.
53 *
54 * We save the fields in big-endian order to allow using the
55 * index file over NFS transparently.
56 */
57struct cache_entry {
58 struct cache_time ce_ctime;
59 struct cache_time ce_mtime;
60 unsigned int ce_dev;
61 unsigned int ce_ino;
62 unsigned int ce_mode;
63 unsigned int ce_uid;
64 unsigned int ce_gid;
65 unsigned int ce_size;
66 unsigned char sha1[20];
67 unsigned short ce_flags;
68 char name[0];
69};
70#define CE_NAMEMASK (0x0fff)
72#define CE_STAGEMASK (0x3000)
73#define CE_STAGESHIFT 12
74#define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
76#define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
77#define ce_size(ce) cache_entry_size(ce_namelen(ce))
78#define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
79#define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
81#define create_ce_mode(mode) htonl(S_IFREG | ce_permissions(mode))
82#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
84const char *sha1_file_directory;
86struct cache_entry **active_cache;
87unsigned int active_nr, active_alloc;
88#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
90#define DEFAULT_DB_ENVIRONMENT ".git/objects"
91#define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
93#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
95#define DEFAULT_INDEX_ENVIRONMENT ".git/index"
96#define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
98#define alloc_nr(x) (((x)+16)*3/2)
100/* Initialize and use the cache information */
102extern int read_cache(void);
103extern int write_cache(int newfd, struct cache_entry **cache, int entries);
104extern int cache_name_pos(const char *name, int namelen);
105extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
106extern int remove_entry_at(int pos);
107extern int remove_file_from_cache(char *path);
108extern int same_name(struct cache_entry *a, struct cache_entry *b);
109extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
110#define MTIME_CHANGED 0x0001
112#define CTIME_CHANGED 0x0002
113#define OWNER_CHANGED 0x0004
114#define MODE_CHANGED 0x0008
115#define INODE_CHANGED 0x0010
116#define DATA_CHANGED 0x0020
117/* Return a statically allocated filename matching the sha1 signature */
119extern char *sha1_file_name(const unsigned char *sha1);
120/* Write a memory buffer out to the sha file */
122extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
123/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
125extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
126extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
127extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
128extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
129extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
131/* Read a tree into the cache */
133extern int read_tree(void *buffer, unsigned long size, int stage);
134extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
136extern int has_sha1_file(const unsigned char *sha1);
138/* Convert to/from hex/sha1 representation */
140extern int get_sha1_hex(const char *hex, unsigned char *sha1);
141extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
142/* General helper functions */
144extern void usage(const char *err);
145extern void die(const char *err, ...);
146extern int error(const char *err, ...);
147extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
149extern void *read_object_with_reference(const unsigned char *sha1,
151 const unsigned char *required_type,
152 unsigned long *size,
153 unsigned char *sha1_ret);
154void parse_date(char *date, char *buf, int bufsize);
156void datestamp(char *buf, int bufsize);
157static inline void *xmalloc(int size)
159{
160 void *ret = malloc(size);
161 if (!ret)
162 die("Out of memory, malloc failed");
163 return ret;
164}
165static inline void *xrealloc(void *ptr, int size)
167{
168 void *ret = realloc(ptr, size);
169 if (!ret)
170 die("Out of memory, realloc failed");
171 return ret;
172}
173#endif /* CACHE_H */