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