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 #ifdef __GNUC__
  36 #define NORETURN __attribute__((__noreturn__))
  37 #else
  38 #define NORETURN
  39 #endif
  40
  41 /*
  42  * Environment variables transition.
  43  * We accept older names for now but warn.
  44  */
  45 extern char *gitenv_bc(const char *);
  46 #define gitenv(e) (getenv(e) ? : gitenv_bc(e))
  47
  48 /*
  49  * Basic data structures for the directory cache
  50  */
  51
  52 #define CACHE_SIGNATURE 0x44495243      /* "DIRC" */
  53 struct cache_header {
  54         unsigned int hdr_signature;
  55         unsigned int hdr_version;
  56         unsigned int hdr_entries;
  57 };
  58
  59 /*
  60  * The "cache_time" is just the low 32 bits of the
  61  * time. It doesn't matter if it overflows - we only
  62  * check it for equality in the 32 bits we save.
  63  */
  64 struct cache_time {
  65         unsigned int sec;
  66         unsigned int nsec;
  67 };
  68
  69 /*
  70  * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  71  * Again - this is just a (very strong in practice) heuristic that
  72  * the inode hasn't changed.
  73  *
  74  * We save the fields in big-endian order to allow using the
  75  * index file over NFS transparently.
  76  */
  77 struct cache_entry {
  78         struct cache_time ce_ctime;
  79         struct cache_time ce_mtime;
  80         unsigned int ce_dev;
  81         unsigned int ce_ino;
  82         unsigned int ce_mode;
  83         unsigned int ce_uid;
  84         unsigned int ce_gid;
  85         unsigned int ce_size;
  86         unsigned char sha1[20];
  87         unsigned short ce_flags;
  88         char name[0];
  89 };
  90
  91 #define CE_NAMEMASK  (0x0fff)
  92 #define CE_STAGEMASK (0x3000)
  93 #define CE_UPDATE    (0x4000)
  94 #define CE_STAGESHIFT 12
  95
  96 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
  97 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
  98 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
  99 #define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
 100
 101 #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
 102 static inline unsigned int create_ce_mode(unsigned int mode)
 103 {
 104         if (S_ISLNK(mode))
 105                 return htonl(S_IFLNK);
 106         return htonl(S_IFREG | ce_permissions(mode));
 107 }
 108
 109 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
 110
 111 extern struct cache_entry **active_cache;
 112 extern unsigned int active_nr, active_alloc, active_cache_changed;
 113
 114 #define GIT_DIR_ENVIRONMENT "GIT_DIR"
 115 #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 116 #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 117 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 118
 119 extern char *get_object_directory(void);
 120 extern char *get_refs_directory(void);
 121 extern char *get_index_file(void);
 122
 123 #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
 124
 125 #define alloc_nr(x) (((x)+16)*3/2)
 126
 127 /* Initialize and use the cache information */
 128 extern int read_cache(void);
 129 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 130 extern int cache_name_pos(const char *name, int namelen);
 131 #define ADD_CACHE_OK_TO_ADD 1           /* Ok to add */
 132 #define ADD_CACHE_OK_TO_REPLACE 2       /* Ok to replace file/directory */
 133 extern int add_cache_entry(struct cache_entry *ce, int option);
 134 extern int remove_cache_entry_at(int pos);
 135 extern int remove_file_from_cache(char *path);
 136 extern int ce_same_name(struct cache_entry *a, struct cache_entry *b);
 137 extern int ce_match_stat(struct cache_entry *ce, struct stat *st);
 138 extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 139 extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
 140
 141 struct cache_file {
 142         struct cache_file *next;
 143         char lockfile[PATH_MAX];
 144 };
 145 extern int hold_index_file_for_update(struct cache_file *, const char *path);
 146 extern int commit_index_file(struct cache_file *);
 147 extern void rollback_index_file(struct cache_file *);
 148
 149 #define MTIME_CHANGED   0x0001
 150 #define CTIME_CHANGED   0x0002
 151 #define OWNER_CHANGED   0x0004
 152 #define MODE_CHANGED    0x0008
 153 #define INODE_CHANGED   0x0010
 154 #define DATA_CHANGED    0x0020
 155 #define TYPE_CHANGED    0x0040
 156
 157 /* Return a statically allocated filename matching the sha1 signature */
 158 extern char *sha1_file_name(const unsigned char *sha1);
 159
 160 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 161 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 162 extern int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size);
 163 extern int parse_sha1_header(char *hdr, char *type, unsigned long *sizep);
 164 extern int sha1_delta_base(const unsigned char *, unsigned char *);
 165 extern int sha1_file_size(const unsigned char *, unsigned long *);
 166 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 167 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 168 extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 169
 170 extern int check_sha1_signature(const unsigned char *sha1, void *buf, unsigned long size, const char *type);
 171
 172 /* Read a tree into the cache */
 173 extern int read_tree(void *buffer, unsigned long size, int stage);
 174
 175 extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 176
 177 extern int has_sha1_file(const unsigned char *sha1);
 178
 179 /* Convert to/from hex/sha1 representation */
 180 extern int get_sha1(const char *str, unsigned char *sha1);
 181 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 182 extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 183
 184 /* General helper functions */
 185 extern void usage(const char *err) NORETURN;
 186 extern void die(const char *err, ...) NORETURN;
 187 extern int error(const char *err, ...);
 188
 189 extern int base_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
 190 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 191
 192 extern void *read_object_with_reference(const unsigned char *sha1,
 193                                         const char *required_type,
 194                                         unsigned long *size,
 195                                         unsigned char *sha1_ret);
 196
 197 const char *show_date(unsigned long time, int timezone);
 198 void parse_date(char *date, char *buf, int bufsize);
 199 void datestamp(char *buf, int bufsize);
 200
 201 static inline void *xmalloc(size_t size)
 202 {
 203         void *ret = malloc(size);
 204         if (!ret)
 205                 die("Out of memory, malloc failed");
 206         return ret;
 207 }
 208
 209 static inline void *xrealloc(void *ptr, size_t size)
 210 {
 211         void *ret = realloc(ptr, size);
 212         if (!ret)
 213                 die("Out of memory, realloc failed");
 214         return ret;
 215 }
 216
 217 static inline void *xcalloc(size_t nmemb, size_t size)
 218 {
 219         void *ret = calloc(nmemb, size);
 220         if (!ret)
 221                 die("Out of memory, calloc failed");
 222         return ret;
 223 }
 224
 225 struct checkout {
 226         const char *base_dir;
 227         int base_dir_len;
 228         unsigned force:1,
 229                  quiet:1,
 230                  not_new:1,
 231                  refresh_cache:1;
 232 };
 233
 234 extern int checkout_entry(struct cache_entry *ce, struct checkout *state);
 235
 236 #endif /* CACHE_H */