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 * Environment variables transition.
  35 * We accept older names for now but warn.
  36 */
  37extern 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" */
  49struct 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 */
  60struct 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 */
  73struct 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)
  97static 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
 106extern struct cache_entry **active_cache;
 107extern 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
 114extern char *get_object_directory(void);
 115extern 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 */
 122extern int read_cache(void);
 123extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 124extern 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 */
 127extern int add_cache_entry(struct cache_entry *ce, int option);
 128extern int remove_entry_at(int pos);
 129extern int remove_file_from_cache(char *path);
 130extern int same_name(struct cache_entry *a, struct cache_entry *b);
 131extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 132extern 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 */
 143extern char *sha1_file_name(const unsigned char *sha1);
 144
 145/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 146extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 147extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 148extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 149extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 150
 151extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 152
 153/* Read a tree into the cache */
 154extern int read_tree(void *buffer, unsigned long size, int stage);
 155
 156extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 157
 158extern int has_sha1_file(const unsigned char *sha1);
 159
 160/* Convert to/from hex/sha1 representation */
 161extern int get_sha1(const char *str, unsigned char *sha1);
 162extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 163extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 164
 165/* General helper functions */
 166extern void usage(const char *err);
 167extern void die(const char *err, ...);
 168extern int error(const char *err, ...);
 169
 170extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 171
 172extern 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
 177const char *show_date(unsigned long time, int timezone);
 178void parse_date(char *date, char *buf, int bufsize);
 179void datestamp(char *buf, int bufsize);
 180
 181static 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
 189static 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 */