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  * Basic data structures for the directory cache
  35  *
  36  * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
  37  * not even trying to be portable. It's trying to be efficient. It's
  38  * just a cache, after all.
  39  */
  40
  41 #define CACHE_SIGNATURE 0x44495243      /* "DIRC" */
  42 struct cache_header {
  43         unsigned int hdr_signature;
  44         unsigned int hdr_version;
  45         unsigned int hdr_entries;
  46 };
  47
  48 /*
  49  * The "cache_time" is just the low 32 bits of the
  50  * time. It doesn't matter if it overflows - we only
  51  * check it for equality in the 32 bits we save.
  52  */
  53 struct cache_time {
  54         unsigned int sec;
  55         unsigned int nsec;
  56 };
  57
  58 /*
  59  * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  60  * Again - this is just a (very strong in practice) heuristic that
  61  * the inode hasn't changed.
  62  *
  63  * We save the fields in big-endian order to allow using the
  64  * index file over NFS transparently.
  65  */
  66 struct cache_entry {
  67         struct cache_time ce_ctime;
  68         struct cache_time ce_mtime;
  69         unsigned int ce_dev;
  70         unsigned int ce_ino;
  71         unsigned int ce_mode;
  72         unsigned int ce_uid;
  73         unsigned int ce_gid;
  74         unsigned int ce_size;
  75         unsigned char sha1[20];
  76         unsigned short ce_flags;
  77         char name[0];
  78 };
  79
  80 #define CE_NAMEMASK  (0x0fff)
  81 #define CE_STAGEMASK (0x3000)
  82 #define CE_STAGESHIFT 12
  83
  84 #define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
  85 #define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
  86 #define ce_size(ce) cache_entry_size(ce_namelen(ce))
  87 #define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
  88
  89 #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
  90 static inline unsigned int create_ce_mode(unsigned int mode)
  91 {
  92         if (S_ISLNK(mode))
  93                 return htonl(S_IFLNK);
  94         return htonl(S_IFREG | ce_permissions(mode));
  95 }
  96
  97 #define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
  98
  99 struct cache_entry **active_cache;
 100 unsigned int active_nr, active_alloc, active_cache_changed;
 101
 102 #define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
 103 #define DEFAULT_DB_ENVIRONMENT ".git/objects"
 104 #define ALTERNATE_DB_ENVIRONMENT "SHA1_FILE_DIRECTORIES"
 105
 106 #define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
 107
 108 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 109 #define DEFAULT_INDEX_ENVIRONMENT ".git/index"
 110
 111 #define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
 112
 113 #define alloc_nr(x) (((x)+16)*3/2)
 114
 115 /* Initialize and use the cache information */
 116 extern int read_cache(void);
 117 extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 118 extern int cache_name_pos(const char *name, int namelen);
 119 extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
 120 extern int remove_entry_at(int pos);
 121 extern int remove_file_from_cache(char *path);
 122 extern int same_name(struct cache_entry *a, struct cache_entry *b);
 123 extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 124 extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 125
 126 #define MTIME_CHANGED   0x0001
 127 #define CTIME_CHANGED   0x0002
 128 #define OWNER_CHANGED   0x0004
 129 #define MODE_CHANGED    0x0008
 130 #define INODE_CHANGED   0x0010
 131 #define DATA_CHANGED    0x0020
 132 #define TYPE_CHANGED    0x0040
 133
 134 /* Return a statically allocated filename matching the sha1 signature */
 135 extern char *sha1_file_name(const unsigned char *sha1);
 136
 137 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 138 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 139 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 140 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 141 extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 142
 143 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 144
 145 /* Read a tree into the cache */
 146 extern int read_tree(void *buffer, unsigned long size, int stage);
 147
 148 extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 149
 150 extern int has_sha1_file(const unsigned char *sha1);
 151
 152 /* Convert to/from hex/sha1 representation */
 153 extern int get_sha1(const char *str, unsigned char *sha1);
 154 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 155 extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 156
 157 /* General helper functions */
 158 extern void usage(const char *err);
 159 extern void die(const char *err, ...);
 160 extern int error(const char *err, ...);
 161
 162 extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 163
 164 extern void *read_object_with_reference(const unsigned char *sha1,
 165                                         const unsigned char *required_type,
 166                                         unsigned long *size,
 167                                         unsigned char *sha1_ret);
 168
 169 const char *show_date(unsigned long time, int timezone);
 170 void parse_date(char *date, char *buf, int bufsize);
 171 void datestamp(char *buf, int bufsize);
 172
 173 static inline void *xmalloc(int size)
 174 {
 175         void *ret = malloc(size);
 176         if (!ret)
 177                 die("Out of memory, malloc failed");
 178         return ret;
 179 }
 180
 181 static inline void *xrealloc(void *ptr, int size)
 182 {
 183         void *ret = realloc(ptr, size);
 184         if (!ret)
 185                 die("Out of memory, realloc failed");
 186         return ret;
 187 }
 188
 189 #endif /* CACHE_H */