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 #include <sys/types.h>
  18 #include <dirent.h>
  19
  20 #include SHA1_HEADER
  21 #include <zlib.h>
  22
  23 #if ZLIB_VERNUM < 0x1200
  24 #define deflateBound(c,s)  ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
  25 #endif
  26
  27 #ifdef DT_UNKNOWN
  28 #define DTYPE(de)       ((de)->d_type)
  29 #else
  30 #define DT_UNKNOWN      0
  31 #define DT_DIR          1
  32 #define DT_REG          2
  33 #define DT_LNK          3
  34 #define DTYPE(de)       DT_UNKNOWN
  35 #endif
  36
  37 #ifdef __GNUC__
  38 #define NORETURN __attribute__((__noreturn__))
  39 #else
  40 #define NORETURN
  41 #endif
  42
  43 /*
  44  * Environment variables transition.
  45  * We accept older names for now but warn.
  46  */
  47 extern char *gitenv_bc(const char *);
  48 #define gitenv(e) (getenv(e) ? : gitenv_bc(e))
  49
  50 /*
  51  * Basic data structures for the directory cache
  52  */
  53
  54 #define CACHE_SIGNATURE 0x44495243      /* "DIRC" */
  55 struct cache_header {
  56         unsigned int hdr_signature;
  57         unsigned int hdr_version;
  58         unsigned int hdr_entries;
  59 };
  60
  61 /*
  62  * The "cache_time" is just the low 32 bits of the
  63  * time. It doesn't matter if it overflows - we only
  64  * check it for equality in the 32 bits we save.
  65  */
  66 struct cache_time {
  67         unsigned int sec;
  68         unsigned int nsec;
  69 };
  70
  71 /*
  72  * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  73  * Again - this is just a (very strong in practice) heuristic that
  74  * the inode hasn't changed.
  75  *
  76  * We save the fields in big-endian order to allow using the
  77  * index file over NFS transparently.
  78  */
  79 struct cache_entry {
  80         struct cache_time ce_ctime;
  81         struct cache_time ce_mtime;
  82         unsigned int ce_dev;
  83         unsigned int ce_ino;
  84         unsigned int ce_mode;
  85         unsigned int ce_uid;
  86         unsigned int ce_gid;
  87         unsigned int ce_size;
  88         unsigned char sha1[20];
  89         unsigned short ce_flags;
  90         char name[0];
  91 };
  92
  93 #define CE_NAMEMASK  (0x0fff)
  94 #define CE_STAGEMASK (0x3000)
  95 #define CE_UPDATE    (0x4000)
  96 #define CE_STAGESHIFT 12
  97
  98 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
  99 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
 100 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
 101 #define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
 102
 103 #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
 104 static inline unsigned int create_ce_mode(unsigned int mode)
 105 {
 106         if (S_ISLNK(mode))
 107                 return htonl(S_IFLNK);
 108         return htonl(S_IFREG | ce_permissions(mode));
 109 }
 110
 111 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
 112
 113 extern struct cache_entry **active_cache;
 114 extern unsigned int active_nr, active_alloc, active_cache_changed;
 115
 116 #define GIT_DIR_ENVIRONMENT "GIT_DIR"
 117 #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 118 #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 119 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 120
 121 extern char *get_object_directory(void);
 122 extern char *get_refs_directory(void);
 123 extern char *get_index_file(void);
 124
 125 #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
 126
 127 #define alloc_nr(x) (((x)+16)*3/2)
 128
 129 /* Initialize and use the cache information */
 130 extern int read_cache(void);
 131 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 132 extern int cache_name_pos(const char *name, int namelen);
 133 #define ADD_CACHE_OK_TO_ADD 1           /* Ok to add */
 134 #define ADD_CACHE_OK_TO_REPLACE 2       /* Ok to replace file/directory */
 135 #define ADD_CACHE_SKIP_DFCHECK 4        /* Ok to skip DF conflict checks */
 136 extern int add_cache_entry(struct cache_entry *ce, int option);
 137 extern int remove_cache_entry_at(int pos);
 138 extern int remove_file_from_cache(char *path);
 139 extern int ce_same_name(struct cache_entry *a, struct cache_entry *b);
 140 extern int ce_match_stat(struct cache_entry *ce, struct stat *st);
 141 extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 142 extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
 143
 144 struct cache_file {
 145         struct cache_file *next;
 146         char lockfile[PATH_MAX];
 147 };
 148 extern int hold_index_file_for_update(struct cache_file *, const char *path);
 149 extern int commit_index_file(struct cache_file *);
 150 extern void rollback_index_file(struct cache_file *);
 151
 152 #define MTIME_CHANGED   0x0001
 153 #define CTIME_CHANGED   0x0002
 154 #define OWNER_CHANGED   0x0004
 155 #define MODE_CHANGED    0x0008
 156 #define INODE_CHANGED   0x0010
 157 #define DATA_CHANGED    0x0020
 158 #define TYPE_CHANGED    0x0040
 159
 160 /* Return a statically allocated filename matching the sha1 signature */
 161 extern char *sha1_file_name(const unsigned char *sha1);
 162
 163 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 164 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 165 extern int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size);
 166 extern int parse_sha1_header(char *hdr, char *type, unsigned long *sizep);
 167 extern int sha1_object_info(const unsigned char *, char *, unsigned long *);
 168 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 169 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 170 extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 171
 172 extern int check_sha1_signature(const unsigned char *sha1, void *buf, unsigned long size, const char *type);
 173
 174 /* Read a tree into the cache */
 175 extern int read_tree(void *buffer, unsigned long size, int stage);
 176
 177 extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 178
 179 extern int has_sha1_file(const unsigned char *sha1);
 180
 181 /* Convert to/from hex/sha1 representation */
 182 extern int get_sha1(const char *str, unsigned char *sha1);
 183 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 184 extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 185
 186 /* General helper functions */
 187 extern void usage(const char *err) NORETURN;
 188 extern void die(const char *err, ...) NORETURN;
 189 extern int error(const char *err, ...);
 190
 191 extern int base_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
 192 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 193
 194 extern void *read_object_with_reference(const unsigned char *sha1,
 195                                         const char *required_type,
 196                                         unsigned long *size,
 197                                         unsigned char *sha1_ret);
 198
 199 const char *show_date(unsigned long time, int timezone);
 200 void parse_date(char *date, char *buf, int bufsize);
 201 void datestamp(char *buf, int bufsize);
 202
 203 static inline void *xmalloc(size_t size)
 204 {
 205         void *ret = malloc(size);
 206         if (!ret)
 207                 die("Out of memory, malloc failed");
 208         return ret;
 209 }
 210
 211 static inline void *xrealloc(void *ptr, size_t size)
 212 {
 213         void *ret = realloc(ptr, size);
 214         if (!ret)
 215                 die("Out of memory, realloc failed");
 216         return ret;
 217 }
 218
 219 static inline void *xcalloc(size_t nmemb, size_t size)
 220 {
 221         void *ret = calloc(nmemb, size);
 222         if (!ret)
 223                 die("Out of memory, calloc failed");
 224         return ret;
 225 }
 226
 227 struct checkout {
 228         const char *base_dir;
 229         int base_dir_len;
 230         unsigned force:1,
 231                  quiet:1,
 232                  not_new:1,
 233                  refresh_cache:1;
 234 };
 235
 236 extern int checkout_entry(struct cache_entry *ce, struct checkout *state);
 237
 238 extern struct alternate_object_database {
 239         char *base;
 240         char *name;
 241 } *alt_odb;
 242 extern void prepare_alt_odb(void);
 243
 244 extern struct packed_git {
 245         struct packed_git *next;
 246         unsigned long index_size;
 247         unsigned long pack_size;
 248         unsigned int *index_base;
 249         void *pack_base;
 250         unsigned int pack_last_used;
 251         unsigned int pack_use_cnt;
 252         char pack_name[0]; /* something like ".git/objects/pack/xxxxx.pack" */
 253 } *packed_git;
 254
 255 struct pack_entry {
 256         unsigned int offset;
 257         unsigned char sha1[20];
 258         struct packed_git *p;
 259 };
 260
 261 extern void prepare_packed_git(void);
 262 extern int use_packed_git(struct packed_git *);
 263 extern void unuse_packed_git(struct packed_git *);
 264 extern struct packed_git *add_packed_git(char *, int);
 265 extern int num_packed_objects(const struct packed_git *p);
 266 extern int nth_packed_object_sha1(const struct packed_git *, int, unsigned char*);
 267 extern int find_pack_entry_one(const unsigned char *, struct pack_entry *, struct packed_git *);
 268 extern void *unpack_entry_gently(struct pack_entry *, char *, unsigned long *);
 269
 270 #endif /* CACHE_H */