Andrew's git - gitweb.git/blob

   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" */
  42struct 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 */
  53struct 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 */
  66struct 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)
  90static 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
  99struct cache_entry **active_cache;
 100unsigned int active_nr, active_alloc, active_cache_changed;
 101
 102#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
 103#define DEFAULT_DB_ENVIRONMENT ".git/objects"
 104
 105#define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
 106
 107#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 108#define DEFAULT_INDEX_ENVIRONMENT ".git/index"
 109
 110#define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
 111
 112#define alloc_nr(x) (((x)+16)*3/2)
 113
 114/* Initialize and use the cache information */
 115extern int read_cache(void);
 116extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 117extern int cache_name_pos(const char *name, int namelen);
 118extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
 119extern int remove_entry_at(int pos);
 120extern int remove_file_from_cache(char *path);
 121extern int same_name(struct cache_entry *a, struct cache_entry *b);
 122extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 123extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 124
 125#define MTIME_CHANGED   0x0001
 126#define CTIME_CHANGED   0x0002
 127#define OWNER_CHANGED   0x0004
 128#define MODE_CHANGED    0x0008
 129#define INODE_CHANGED   0x0010
 130#define DATA_CHANGED    0x0020
 131#define TYPE_CHANGED    0x0040
 132
 133/* Return a statically allocated filename matching the sha1 signature */
 134extern char *sha1_file_name(const unsigned char *sha1);
 135
 136/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 137extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 138extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 139extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 140extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 141
 142extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 143
 144/* Read a tree into the cache */
 145extern int read_tree(void *buffer, unsigned long size, int stage);
 146
 147extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 148
 149extern int has_sha1_file(const unsigned char *sha1);
 150
 151/* Convert to/from hex/sha1 representation */
 152extern int get_sha1(const char *str, unsigned char *sha1);
 153extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 154extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 155
 156/* General helper functions */
 157extern void usage(const char *err);
 158extern void die(const char *err, ...);
 159extern int error(const char *err, ...);
 160
 161extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 162
 163extern void *read_object_with_reference(const unsigned char *sha1,
 164                                        const unsigned char *required_type,
 165                                        unsigned long *size,
 166                                        unsigned char *sha1_ret);
 167
 168const char *show_date(unsigned long time, int timezone);
 169void parse_date(char *date, char *buf, int bufsize);
 170void datestamp(char *buf, int bufsize);
 171
 172static inline void *xmalloc(int size)
 173{
 174        void *ret = malloc(size);
 175        if (!ret)
 176                die("Out of memory, malloc failed");
 177        return ret;
 178}
 179
 180static inline void *xrealloc(void *ptr, int size)
 181{
 182        void *ret = realloc(ptr, size);
 183        if (!ret)
 184                die("Out of memory, realloc failed");
 185        return ret;
 186}
 187
 188#endif /* CACHE_H */