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