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/*
  21 * Basic data structures for the directory cache
  22 *
  23 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's
  24 * not even trying to be portable. It's trying to be efficient. It's
  25 * just a cache, after all.
  26 */
  27
  28#define CACHE_SIGNATURE 0x44495243      /* "DIRC" */
  29struct cache_header {
  30        unsigned int hdr_signature;
  31        unsigned int hdr_version;
  32        unsigned int hdr_entries;
  33};
  34
  35/*
  36 * The "cache_time" is just the low 32 bits of the
  37 * time. It doesn't matter if it overflows - we only
  38 * check it for equality in the 32 bits we save.
  39 */
  40struct cache_time {
  41        unsigned int sec;
  42        unsigned int nsec;
  43};
  44
  45/*
  46 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
  47 * Again - this is just a (very strong in practice) heuristic that
  48 * the inode hasn't changed.
  49 *
  50 * We save the fields in big-endian order to allow using the
  51 * index file over NFS transparently.
  52 */
  53struct cache_entry {
  54        struct cache_time ce_ctime;
  55        struct cache_time ce_mtime;
  56        unsigned int ce_dev;
  57        unsigned int ce_ino;
  58        unsigned int ce_mode;
  59        unsigned int ce_uid;
  60        unsigned int ce_gid;
  61        unsigned int ce_size;
  62        unsigned char sha1[20];
  63        unsigned short ce_flags;
  64        char name[0];
  65};
  66
  67#define CE_NAMEMASK  (0x0fff)
  68#define CE_STAGEMASK (0x3000)
  69#define CE_STAGESHIFT 12
  70
  71#define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
  72#define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
  73#define ce_size(ce) cache_entry_size(ce_namelen(ce))
  74#define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
  75
  76#define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
  77#define create_ce_mode(mode) htonl(S_IFREG | ce_permissions(mode))
  78
  79#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
  80
  81const char *sha1_file_directory;
  82struct cache_entry **active_cache;
  83unsigned int active_nr, active_alloc;
  84
  85#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
  86#define DEFAULT_DB_ENVIRONMENT ".git/objects"
  87
  88#define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
  89
  90#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
  91#define DEFAULT_INDEX_ENVIRONMENT ".git/index"
  92
  93#define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
  94
  95#define alloc_nr(x) (((x)+16)*3/2)
  96
  97/* Initialize and use the cache information */
  98extern int read_cache(void);
  99extern int write_cache(int newfd, struct cache_entry **cache, int entries);
 100extern int cache_name_pos(const char *name, int namelen);
 101extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
 102extern int remove_entry_at(int pos);
 103extern int remove_file_from_cache(char *path);
 104extern int same_name(struct cache_entry *a, struct cache_entry *b);
 105extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 106
 107#define MTIME_CHANGED   0x0001
 108#define CTIME_CHANGED   0x0002
 109#define OWNER_CHANGED   0x0004
 110#define MODE_CHANGED    0x0008
 111#define INODE_CHANGED   0x0010
 112#define DATA_CHANGED    0x0020
 113
 114/* Return a statically allocated filename matching the sha1 signature */
 115extern char *sha1_file_name(const unsigned char *sha1);
 116
 117/* Write a memory buffer out to the sha file */
 118extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
 119
 120/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 121extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 122extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 123extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 124extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 125
 126extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 127
 128/* Read a tree into the cache */
 129extern int read_tree(void *buffer, unsigned long size, int stage);
 130
 131extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
 132
 133extern int has_sha1_file(const unsigned char *sha1);
 134
 135/* Convert to/from hex/sha1 representation */
 136extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 137extern char *sha1_to_hex(const unsigned char *sha1);    /* static buffer result! */
 138
 139/* General helper functions */
 140extern void usage(const char *err);
 141extern void die(const char *err, ...);
 142extern int error(const char *err, ...);
 143
 144extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
 145
 146extern void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
 147                                                unsigned long *size,
 148                                                unsigned char *tree_sha1_ret);
 149
 150static inline void *xmalloc(int size)
 151{
 152        void *ret = malloc(size);
 153        if (!ret)
 154                die("Out of memory, malloc failed");
 155        return ret;
 156}
 157
 158static inline void *xrealloc(void *ptr, int size)
 159{
 160        void *ret = realloc(ptr, size);
 161        if (!ret)
 162                die("Out of memory, realloc failed");
 163        return ret;
 164}
 165
 166#endif /* CACHE_H */