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 <limits.h>
  14 #include <sys/mman.h>
  15 #include <sys/param.h>
  16 #include <netinet/in.h>
  17
  18 #include SHA1_HEADER
  19 #include <zlib.h>
  20
  21 #if ZLIB_VERNUM < 0x1200
  22 #define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
  23 #endif
  24
  25 #ifdef DT_UNKNOWN
  26 #define DTYPE(de)       ((de)->d_type)
  27 #else
  28 #define DT_UNKNOWN      0
  29 #define DT_DIR          1
  30 #define DT_REG          2
  31 #define DT_LNK          3
  32 #define DTYPE(de)       DT_UNKNOWN
  33 #endif
  34
  35 /*
  36  * Environment variables transition.
  37  * We accept older names for now but warn.
  38  */
  39 extern char *gitenv_bc(const char *);
  40 #define gitenv(e) (getenv(e) ? : gitenv_bc(e))
  41
  42 /*
  43  * Basic data structures for the directory cache
  44  */
  45
  46 #define CACHE_SIGNATURE 0x44495243      /* "DIRC" */
  47 struct cache_header {
  48         unsigned int hdr_signature;
  49         unsigned int hdr_version;
  50         unsigned int hdr_entries;
  51 };
  52
  53 /*
  54  * The "cache_time" is just the low 32 bits of the
  55  * time. It doesn't matter if it overflows - we only
  56  * check it for equality in the 32 bits we save.
  57  */
  58 struct cache_time {
  59         unsigned int sec;
  60         unsigned int nsec;
  61 };
  62
  63 /*
  64  * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  65  * Again - this is just a (very strong in practice) heuristic that
  66  * the inode hasn't changed.
  67  *
  68  * We save the fields in big-endian order to allow using the
  69  * index file over NFS transparently.
  70  */
  71 struct cache_entry {
  72         struct cache_time ce_ctime;
  73         struct cache_time ce_mtime;
  74         unsigned int ce_dev;
  75         unsigned int ce_ino;
  76         unsigned int ce_mode;
  77         unsigned int ce_uid;
  78         unsigned int ce_gid;
  79         unsigned int ce_size;
  80         unsigned char sha1[20];
  81         unsigned short ce_flags;
  82         char name[0];
  83 };
  84
  85 #define CE_NAMEMASK  (0x0fff)
  86 #define CE_STAGEMASK (0x3000)
  87 #define CE_STAGESHIFT 12
  88
  89 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
  90 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
  91 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
  92 #define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
  93
  94 #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
  95 static inline unsigned int create_ce_mode(unsigned int mode)
  96 {
  97         if (S_ISLNK(mode))
  98                 return htonl(S_IFLNK);
  99         return htonl(S_IFREG | ce_permissions(mode));
 100 }
 101
 102 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
 103
 104 extern struct cache_entry **active_cache;
 105 extern unsigned int active_nr, active_alloc, active_cache_changed;
 106
 107 #define GIT_DIR_ENVIRONMENT "GIT_DIR"
 108 #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 109 #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 110 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 111
 112 extern char *get_object_directory(void);
 113 extern char *get_index_file(void);
 114
 115 #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
 116
 117 #define alloc_nr(x) (((x)+16)*3/2)
 118
 119 /* Initialize and use the cache information */
 120 extern int read_cache(void);
 121 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 122 extern int cache_name_pos(const char *name, int namelen);
 123 #define ADD_CACHE_OK_TO_ADD 1           /* Ok to add */
 124 #define ADD_CACHE_OK_TO_REPLACE 2       /* Ok to replace file/directory */
 125 extern int add_cache_entry(struct cache_entry *ce, int option);
 126 extern int remove_cache_entry_at(int pos);
 127 extern int remove_file_from_cache(char *path);
 128 extern int ce_same_name(struct cache_entry *a, struct cache_entry *b);
 129 extern int ce_match_stat(struct cache_entry *ce, struct stat *st);
 130 extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 131 extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
 132
 133 struct cache_file {
 134         struct cache_file *next;
 135         char lockfile[PATH_MAX];
 136 };
 137 extern int hold_index_file_for_update(struct cache_file *, const char *path);
 138 extern int commit_index_file(struct cache_file *);
 139 extern void rollback_index_file(struct cache_file *);
 140
 141 #define MTIME_CHANGED   0x0001
 142 #define CTIME_CHANGED   0x0002
 143 #define OWNER_CHANGED   0x0004
 144 #define MODE_CHANGED    0x0008
 145 #define INODE_CHANGED   0x0010
 146 #define DATA_CHANGED    0x0020
 147 #define TYPE_CHANGED    0x0040
 148
 149 /* Return a statically allocated filename matching the sha1 signature */
 150 extern char *sha1_file_name(const unsigned char *sha1);
 151
 152 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 153 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 154 extern int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size);
 155 extern int parse_sha1_header(char *hdr, char *type, unsigned long *sizep);
 156 extern int sha1_delta_base(const unsigned char *, unsigned char *);
 157 extern int sha1_file_size(const unsigned char *, unsigned long *);
 158 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 159 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 160 extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 161
 162 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 163
 164 /* Read a tree into the cache */
 165 extern int read_tree(void *buffer, unsigned long size, int stage);
 166
 167 extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 168
 169 extern int has_sha1_file(const unsigned char *sha1);
 170
 171 /* Convert to/from hex/sha1 representation */
 172 extern int get_sha1(const char *str, unsigned char *sha1);
 173 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 174 extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 175
 176 /* General helper functions */
 177 extern void usage(const char *err);
 178 extern void die(const char *err, ...);
 179 extern int error(const char *err, ...);
 180
 181 extern int base_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
 182 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 183
 184 extern void *read_object_with_reference(const unsigned char *sha1,
 185                                         const char *required_type,
 186                                         unsigned long *size,
 187                                         unsigned char *sha1_ret);
 188
 189 const char *show_date(unsigned long time, int timezone);
 190 void parse_date(char *date, char *buf, int bufsize);
 191 void datestamp(char *buf, int bufsize);
 192
 193 static inline void *xmalloc(size_t size)
 194 {
 195         void *ret = malloc(size);
 196         if (!ret)
 197                 die("Out of memory, malloc failed");
 198         return ret;
 199 }
 200
 201 static inline void *xrealloc(void *ptr, size_t size)
 202 {
 203         void *ret = realloc(ptr, size);
 204         if (!ret)
 205                 die("Out of memory, realloc failed");
 206         return ret;
 207 }
 208
 209 static inline void *xcalloc(size_t nmemb, size_t size)
 210 {
 211         void *ret = calloc(nmemb, size);
 212         if (!ret)
 213                 die("Out of memory, calloc failed");
 214         return ret;
 215 }
 216
 217 #endif /* CACHE_H */