[thirdparty/git.git] / cache.h

#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 <string.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;
	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 and use the cache information */
extern int read_cache(void);
extern int cache_name_pos(const char *name, int namelen);
extern int cache_match_stat(struct cache_entry *ce, struct stat *st);

#define MTIME_CHANGED	0x0001
#define CTIME_CHANGED	0x0002
#define OWNER_CHANGED	0x0004
#define MODE_CHANGED    0x0008
#define INODE_CHANGED   0x0010
#define DATA_CHANGED    0x0020

/* 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 * map_sha1_file(unsigned char *sha1, unsigned long *size);
extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
extern void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size);
extern int write_sha1_file(char *buf, unsigned len);
extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size);

/* 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 */
Commit	Line	Data
e83c5163 LT	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>
bf0c6e83	10	#include <string.h>
e83c5163 LT	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" */
	26	struct 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	*/
	38	struct 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	*/
	48	struct 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;
59c1e249	59	char name[0];
e83c5163 LT	60	};
	61
	62	const char *sha1_file_directory;
	63	struct cache_entry **active_cache;
	64	unsigned 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
734aab75	74	/* Initialize and use the cache information */
e83c5163	75	extern int read_cache(void);
eb38c22f	76	extern int cache_name_pos(const char *name, int namelen);
734aab75 LT	77	extern int cache_match_stat(struct cache_entry ce, struct stat st);
	78
	79	#define MTIME_CHANGED 0x0001
	80	#define CTIME_CHANGED 0x0002
	81	#define OWNER_CHANGED 0x0004
	82	#define MODE_CHANGED 0x0008
	83	#define INODE_CHANGED 0x0010
	84	#define DATA_CHANGED 0x0020
e83c5163 LT	85
	86	/* Return a statically allocated filename matching the sha1 signature */
	87	extern char sha1_file_name(unsigned char sha1);
	88
	89	/* Write a memory buffer out to the sha file */
	90	extern int write_sha1_buffer(unsigned char sha1, void buf, unsigned int size);
	91
	92	/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
24778e33	93	extern void * map_sha1_file(unsigned char sha1, unsigned long size);
2ade9340	94	extern void * unpack_sha1_file(void map, unsigned long mapsize, char type, unsigned long *size);
e83c5163 LT	95	extern void * read_sha1_file(unsigned char sha1, char type, unsigned long *size);
e83c5163 LT	96	extern int write_sha1_file(char *buf, unsigned len);
24778e33	97	extern int check_sha1_signature(unsigned char sha1, void buf, unsigned long size);
e83c5163 LT	98
	99	/* Convert to/from hex/sha1 representation */
	100	extern int get_sha1_hex(char hex, unsigned char sha1);
	101	extern char sha1_to_hex(unsigned char sha1); /* static buffer! */
	102
	103	/* General helper functions */
	104	extern void usage(const char *err);
	105
	106	#endif /* CACHE_H */