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#include <netinet/in.h> 14 15#include <openssl/sha.h> 16#include <zlib.h> 17 18/* 19 * Basic data structures for the directory cache 20 * 21 * NOTE NOTE NOTE! This is all in the native CPU byte format. It's 22 * not even trying to be portable. It's trying to be efficient. It's 23 * just a cache, after all. 24 */ 25 26#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */ 27struct cache_header { 28 unsigned int hdr_signature; 29 unsigned int hdr_version; 30 unsigned int hdr_entries; 31 unsigned char sha1[20]; 32}; 33 34/* 35 * The "cache_time" is just the low 32 bits of the 36 * time. It doesn't matter if it overflows - we only 37 * check it for equality in the 32 bits we save. 38 */ 39struct cache_time { 40 unsigned int sec; 41 unsigned int nsec; 42}; 43 44/* 45 * dev/ino/uid/gid/size are also just tracked to the low 32 bits 46 * Again - this is just a (very strong in practice) heuristic that 47 * the inode hasn't changed. 48 * 49 * We save the fields in big-endian order to allow using the 50 * index file over NFS transparently. 51 */ 52struct cache_entry { 53 struct cache_time ce_ctime; 54 struct cache_time ce_mtime; 55 unsigned int ce_dev; 56 unsigned int ce_ino; 57 unsigned int ce_mode; 58 unsigned int ce_uid; 59 unsigned int ce_gid; 60 unsigned int ce_size; 61 unsigned char sha1[20]; 62 unsigned short ce_namelen; 63 char name[0]; 64}; 65 66const char *sha1_file_directory; 67struct cache_entry **active_cache; 68unsigned int active_nr, active_alloc; 69 70#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY" 71#define DEFAULT_DB_ENVIRONMENT ".git/objects" 72 73#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7) 74#define ce_namelen(ce) ntohs((ce)->ce_namelen) 75#define ce_size(ce) cache_entry_size(ce_namelen(ce)) 76 77#define alloc_nr(x) (((x)+16)*3/2) 78 79/* Initialize and use the cache information */ 80extern int read_cache(void); 81extern int write_cache(int newfd, struct cache_entry **cache, int entries); 82extern int cache_name_pos(const char *name, int namelen); 83extern int add_cache_entry(struct cache_entry *ce, int ok_to_add); 84extern int remove_file_from_cache(char *path); 85extern int cache_match_stat(struct cache_entry *ce, struct stat *st); 86 87#define MTIME_CHANGED 0x0001 88#define CTIME_CHANGED 0x0002 89#define OWNER_CHANGED 0x0004 90#define MODE_CHANGED 0x0008 91#define INODE_CHANGED 0x0010 92#define DATA_CHANGED 0x0020 93 94/* Return a statically allocated filename matching the sha1 signature */ 95extern char *sha1_file_name(const unsigned char *sha1); 96 97/* Write a memory buffer out to the sha file */ 98extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size); 99 100/* Read and unpack a sha1 file into memory, write memory to a sha1 file */ 101extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size); 102extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size); 103extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size); 104extern int write_sha1_file(char *buf, unsigned len, unsigned char *return_sha1); 105extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size); 106 107/* Convert to/from hex/sha1 representation */ 108extern int get_sha1_hex(const char *hex, unsigned char *sha1); 109extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */ 110 111/* General helper functions */ 112extern void usage(const char *err); 113extern void die(const char *err, ...); 114extern int error(const char *err, ...); 115 116extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2); 117 118#endif /* CACHE_H */