diff options
Diffstat (limited to 'cache.h')
| -rw-r--r-- | cache.h | 93 |
1 files changed, 93 insertions, 0 deletions
@@ -0,0 +1,93 @@ +#ifndef CACHE_H +#define CACHE_H + +#include <stdio.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <stddef.h> +#include <stdlib.h> +#include <stdarg.h> +#include <errno.h> +#include <sys/mman.h> + +#include <openssl/sha.h> +#include <zlib.h> + +/* + * Basic data structures for the directory cache + * + * NOTE NOTE NOTE! This is all in the native CPU byte format. It's + * not even trying to be portable. It's trying to be efficient. It's + * just a cache, after all. + */ + +#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */ +struct cache_header { + unsigned int signature; + unsigned int version; + unsigned int entries; + unsigned char sha1[20]; +}; + +/* + * The "cache_time" is just the low 32 bits of the + * time. It doesn't matter if it overflows - we only + * check it for equality in the 32 bits we save. + */ +struct cache_time { + unsigned int sec; + unsigned int nsec; +}; + +/* + * dev/ino/uid/gid/size are also just tracked to the low 32 bits + * Again - this is just a (very strong in practice) heuristic that + * the inode hasn't changed. + */ +struct cache_entry { + struct cache_time ctime; + struct cache_time mtime; + unsigned int st_dev; + unsigned int st_ino; + unsigned int st_mode; + unsigned int st_uid; + unsigned int st_gid; + unsigned int st_size; + unsigned char sha1[20]; + unsigned short namelen; + unsigned char name[0]; +}; + +const char *sha1_file_directory; +struct cache_entry **active_cache; +unsigned int active_nr, active_alloc; + +#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY" +#define DEFAULT_DB_ENVIRONMENT ".dircache/objects" + +#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7) +#define ce_size(ce) cache_entry_size((ce)->namelen) + +#define alloc_nr(x) (((x)+16)*3/2) + +/* Initialize the cache information */ +extern int read_cache(void); + +/* Return a statically allocated filename matching the sha1 signature */ +extern char *sha1_file_name(unsigned char *sha1); + +/* Write a memory buffer out to the sha file */ +extern int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size); + +/* Read and unpack a sha1 file into memory, write memory to a sha1 file */ +extern void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size); +extern int write_sha1_file(char *buf, unsigned len); + +/* Convert to/from hex/sha1 representation */ +extern int get_sha1_hex(char *hex, unsigned char *sha1); +extern char *sha1_to_hex(unsigned char *sha1); /* static buffer! */ + +/* General helper functions */ +extern void usage(const char *err); + +#endif /* CACHE_H */ |