Andrew's git - gitweb.git/blob

94f22c21d1b0002a6e9af824c17d8e797ccde4a0
   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)
  90#define create_ce_mode(mode) htonl(S_IFREG | ce_permissions(mode))
  91
  92#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
  93
  94const char *sha1_file_directory;
  95struct cache_entry **active_cache;
  96unsigned int active_nr, active_alloc;
  97
  98#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
  99#define DEFAULT_DB_ENVIRONMENT ".git/objects"
 100
 101#define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
 102
 103#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
 104#define DEFAULT_INDEX_ENVIRONMENT ".git/index"
 105
 106#define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
 107
 108#define alloc_nr(x) (((x)+16)*3/2)
 109
 110/* Initialize and use the cache information */
 111extern int read_cache(void);
 112extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 113extern int cache_name_pos(const char *name, int namelen);
 114extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
 115extern int remove_entry_at(int pos);
 116extern int remove_file_from_cache(char *path);
 117extern int same_name(struct cache_entry *a, struct cache_entry *b);
 118extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 119extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
 120
 121#define MTIME_CHANGED   0x0001
 122#define CTIME_CHANGED   0x0002
 123#define OWNER_CHANGED   0x0004
 124#define MODE_CHANGED    0x0008
 125#define INODE_CHANGED   0x0010
 126#define DATA_CHANGED    0x0020
 127
 128/* Return a statically allocated filename matching the sha1 signature */
 129extern char *sha1_file_name(const unsigned char *sha1);
 130
 131/* Write a memory buffer out to the sha file */
 132extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
 133
 134/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 135extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 136extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 137extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 138extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 139
 140extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 141
 142/* Read a tree into the cache */
 143extern int read_tree(void *buffer, unsigned long size, int stage);
 144
 145extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 146
 147extern int has_sha1_file(const unsigned char *sha1);
 148
 149/* Convert to/from hex/sha1 representation */
 150extern int get_sha1(const char *str, unsigned char *sha1);
 151extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 152extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 153
 154/* General helper functions */
 155extern void usage(const char *err);
 156extern void die(const char *err, ...);
 157extern int error(const char *err, ...);
 158
 159extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 160
 161extern void *read_object_with_reference(const unsigned char *sha1,
 162                                        const unsigned char *required_type,
 163                                        unsigned long *size,
 164                                        unsigned char *sha1_ret);
 165
 166void parse_date(char *date, char *buf, int bufsize);
 167void datestamp(char *buf, int bufsize);
 168
 169static inline void *xmalloc(int size)
 170{
 171        void *ret = malloc(size);
 172        if (!ret)
 173                die("Out of memory, malloc failed");
 174        return ret;
 175}
 176
 177static inline void *xrealloc(void *ptr, int size)
 178{
 179        void *ret = realloc(ptr, size);
 180        if (!ret)
 181                die("Out of memory, realloc failed");
 182        return ret;
 183}
 184
 185#endif /* CACHE_H */