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cache.h
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#ifndef CACHE_H
#define CACHE_H
#include <unistd.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 <sys/param.h>
#include <netinet/in.h>
#include SHA1_HEADER
#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 hdr_signature;
unsigned int hdr_version;
unsigned int hdr_entries;
};
/*
* 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.
*
* We save the fields in big-endian order to allow using the
* index file over NFS transparently.
*/
struct cache_entry {
struct cache_time ce_ctime;
struct cache_time ce_mtime;
unsigned int ce_dev;
unsigned int ce_ino;
unsigned int ce_mode;
unsigned int ce_uid;
unsigned int ce_gid;
unsigned int ce_size;
unsigned char sha1[20];
unsigned short ce_flags;
char name[0];
};
#define CE_NAMEMASK (0x0fff)
#define CE_STAGEMASK (0x3000)
#define CE_STAGESHIFT 12
#define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
#define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
#define ce_size(ce) cache_entry_size(ce_namelen(ce))
#define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
#define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
#define create_ce_mode(mode) htonl(S_IFREG | ce_permissions(mode))
#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
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 ".git/objects"
#define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
#define DEFAULT_INDEX_ENVIRONMENT ".git/index"
#define get_index_file() (getenv(INDEX_ENVIRONMENT) ? : DEFAULT_INDEX_ENVIRONMENT)
#define alloc_nr(x) (((x)+16)*3/2)
/* Initialize and use the cache information */
extern int read_cache(void);
extern int write_cache(int newfd, struct cache_entry **cache, int entries);
extern int cache_name_pos(const char *name, int namelen);
extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
extern int remove_entry_at(int pos);
extern int remove_file_from_cache(char *path);
extern int same_name(struct cache_entry *a, struct cache_entry *b);
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(const unsigned char *sha1);
/* Write a memory buffer out to the sha file */
extern int write_sha1_buffer(const 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(const 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(const unsigned char *sha1, char *type, unsigned long *size);
extern int write_sha1_file(char *buf, unsigned long len, const char *type, unsigned char *return_sha1);
extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
/* Read a tree into the cache */
extern int read_tree(void *buffer, unsigned long size, int stage);
extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
extern int has_sha1_file(const unsigned char *sha1);
/* Convert to/from hex/sha1 representation */
extern int get_sha1_hex(const char *hex, unsigned char *sha1);
extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
/* General helper functions */
extern void usage(const char *err);
extern void die(const char *err, ...);
extern int error(const char *err, ...);
extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
extern void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
unsigned long *size,
unsigned char *tree_sha1_ret);
static inline void *xmalloc(int size)
{
void *ret = malloc(size);
if (!ret)
die("Out of memory, malloc failed");
return ret;
}
static inline void *xrealloc(void *ptr, int size)
{
void *ret = realloc(ptr, size);
if (!ret)
die("Out of memory, realloc failed");
return ret;
}
#endif /* CACHE_H */