1#ifndef CACHE_H 2#define CACHE_H 3 4#include <stdio.h> 5#include <sys/stat.h> 6#include <fcntl.h> 7#include <stddef.h> 8#include <stdlib.h> 9#include <stdarg.h> 10#include <string.h> 11#include <errno.h> 12#include <sys/mman.h> 13 14#include <openssl/sha.h> 15#include <zlib.h> 16 17/* 18 * Basic data structures for the directory cache 19 * 20 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's 21 * not even trying to be portable. It's trying to be efficient. It's 22 * just a cache, after all. 23 */ 24 25#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */ 26struct cache_header { 27 unsigned int signature; 28 unsigned int version; 29 unsigned int entries; 30 unsigned char sha1[20]; 31}; 32 33/* 34 * The "cache_time" is just the low 32 bits of the 35 * time. It doesn't matter if it overflows - we only 36 * check it for equality in the 32 bits we save. 37 */ 38struct cache_time { 39 unsigned int sec; 40 unsigned int nsec; 41}; 42 43/* 44 * dev/ino/uid/gid/size are also just tracked to the low 32 bits 45 * Again - this is just a (very strong in practice) heuristic that 46 * the inode hasn't changed. 47 */ 48struct cache_entry { 49 struct cache_time ctime; 50 struct cache_time mtime; 51 unsigned int st_dev; 52 unsigned int st_ino; 53 unsigned int st_mode; 54 unsigned int st_uid; 55 unsigned int st_gid; 56 unsigned int st_size; 57 unsigned char sha1[20]; 58 unsigned short namelen; 59 unsigned char name[0]; 60}; 61 62const char *sha1_file_directory; 63struct cache_entry **active_cache; 64unsigned int active_nr, active_alloc; 65 66#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY" 67#define DEFAULT_DB_ENVIRONMENT ".dircache/objects" 68 69#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7) 70#define ce_size(ce) cache_entry_size((ce)->namelen) 71 72#define alloc_nr(x) (((x)+16)*3/2) 73 74/* Initialize the cache information */ 75extern int read_cache(void); 76 77/* Return a statically allocated filename matching the sha1 signature */ 78extern char *sha1_file_name(unsigned char *sha1); 79 80/* Write a memory buffer out to the sha file */ 81extern int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size); 82 83/* Read and unpack a sha1 file into memory, write memory to a sha1 file */ 84extern void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size); 85extern int write_sha1_file(char *buf, unsigned len); 86 87/* Convert to/from hex/sha1 representation */ 88extern int get_sha1_hex(char *hex, unsigned char *sha1); 89extern char *sha1_to_hex(unsigned char *sha1); /* static buffer! */ 90 91/* General helper functions */ 92extern void usage(const char *err); 93 94#endif /* CACHE_H */