Andrew's git - gitweb.git/blob

7696766dde0c8bd566a4529d6fa755da32f1482e
   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 */
  38extern 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 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
  45 * not even trying to be portable. It's trying to be efficient. It's
  46 * just a cache, after all.
  47 */
  48
  49#define CACHE_SIGNATURE 0x44495243      /* "DIRC" */
  50struct cache_header {
  51        unsigned int hdr_signature;
  52        unsigned int hdr_version;
  53        unsigned int hdr_entries;
  54};
  55
  56/*
  57 * The "cache_time" is just the low 32 bits of the
  58 * time. It doesn't matter if it overflows - we only
  59 * check it for equality in the 32 bits we save.
  60 */
  61struct cache_time {
  62        unsigned int sec;
  63        unsigned int nsec;
  64};
  65
  66/*
  67 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  68 * Again - this is just a (very strong in practice) heuristic that
  69 * the inode hasn't changed.
  70 *
  71 * We save the fields in big-endian order to allow using the
  72 * index file over NFS transparently.
  73 */
  74struct cache_entry {
  75        struct cache_time ce_ctime;
  76        struct cache_time ce_mtime;
  77        unsigned int ce_dev;
  78        unsigned int ce_ino;
  79        unsigned int ce_mode;
  80        unsigned int ce_uid;
  81        unsigned int ce_gid;
  82        unsigned int ce_size;
  83        unsigned char sha1[20];
  84        unsigned short ce_flags;
  85        char name[0];
  86};
  87
  88#define CE_NAMEMASK  (0x0fff)
  89#define CE_STAGEMASK (0x3000)
  90#define CE_STAGESHIFT 12
  91
  92#define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
  93#define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
  94#define ce_size(ce) cache_entry_size(ce_namelen(ce))
  95#define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
  96
  97#define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
  98static inline unsigned int create_ce_mode(unsigned int mode)
  99{
 100        if (S_ISLNK(mode))
 101                return htonl(S_IFLNK);
 102        return htonl(S_IFREG | ce_permissions(mode));
 103}
 104
 105#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
 106
 107extern struct cache_entry **active_cache;
 108extern unsigned int active_nr, active_alloc, active_cache_changed;
 109
 110#define GIT_DIR_ENVIRONMENT "GIT_DIR"
 111#define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 112#define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 113#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 114
 115extern char *get_object_directory(void);
 116extern char *get_index_file(void);
 117
 118#define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
 119
 120#define alloc_nr(x) (((x)+16)*3/2)
 121
 122/* Initialize and use the cache information */
 123extern int read_cache(void);
 124extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 125extern int cache_name_pos(const char *name, int namelen);
 126#define ADD_CACHE_OK_TO_ADD 1           /* Ok to add */
 127#define ADD_CACHE_OK_TO_REPLACE 2       /* Ok to replace file/directory */
 128extern int add_cache_entry(struct cache_entry *ce, int option);
 129extern int remove_entry_at(int pos);
 130extern int remove_file_from_cache(char *path);
 131extern int same_name(struct cache_entry *a, struct cache_entry *b);
 132extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 133extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 134
 135#define MTIME_CHANGED   0x0001
 136#define CTIME_CHANGED   0x0002
 137#define OWNER_CHANGED   0x0004
 138#define MODE_CHANGED    0x0008
 139#define INODE_CHANGED   0x0010
 140#define DATA_CHANGED    0x0020
 141#define TYPE_CHANGED    0x0040
 142
 143/* Return a statically allocated filename matching the sha1 signature */
 144extern char *sha1_file_name(const unsigned char *sha1);
 145
 146/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 147extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 148extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 149extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 150extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 151
 152extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 153
 154/* Read a tree into the cache */
 155extern int read_tree(void *buffer, unsigned long size, int stage);
 156
 157extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 158
 159extern int has_sha1_file(const unsigned char *sha1);
 160
 161/* Convert to/from hex/sha1 representation */
 162extern int get_sha1(const char *str, unsigned char *sha1);
 163extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 164extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 165
 166/* General helper functions */
 167extern void usage(const char *err);
 168extern void die(const char *err, ...);
 169extern int error(const char *err, ...);
 170
 171extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 172
 173extern void *read_object_with_reference(const unsigned char *sha1,
 174                                        const unsigned char *required_type,
 175                                        unsigned long *size,
 176                                        unsigned char *sha1_ret);
 177
 178const char *show_date(unsigned long time, int timezone);
 179void parse_date(char *date, char *buf, int bufsize);
 180void datestamp(char *buf, int bufsize);
 181
 182static inline void *xmalloc(size_t size)
 183{
 184        void *ret = malloc(size);
 185        if (!ret)
 186                die("Out of memory, malloc failed");
 187        return ret;
 188}
 189
 190static inline void *xrealloc(void *ptr, size_t size)
 191{
 192        void *ret = realloc(ptr, size);
 193        if (!ret)
 194                die("Out of memory, realloc failed");
 195        return ret;
 196}
 197
 198static inline void *xcalloc(size_t nmemb, size_t size)
 199{
 200        void *ret = calloc(nmemb, size);
 201        if (!ret)
 202                die("Out of memory, calloc failed");
 203        return ret;
 204}
 205
 206#endif /* CACHE_H */