mirror of
https://github.com/git/git.git
synced 2024-11-24 18:33:43 +08:00
5180cacc20
Make a separate helper for parsing the header of an object file (really carefully) and for unpacking the rest. This means that anybody who uses the "unpack_sha1_header()" interface can easily look at the header and decide to unpack the rest too, without doing any extra work.
216 lines
6.5 KiB
C
216 lines
6.5 KiB
C
#ifndef CACHE_H
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#define CACHE_H
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#include <unistd.h>
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#include <stdio.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <string.h>
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#include <errno.h>
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#include <limits.h>
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <netinet/in.h>
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#include SHA1_HEADER
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#include <zlib.h>
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#if ZLIB_VERNUM < 0x1200
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#define deflateBound(c,s) ((s) + (((s) + 7) >> 3) + (((s) + 63) >> 6) + 11)
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#endif
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#ifdef DT_UNKNOWN
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#define DTYPE(de) ((de)->d_type)
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#else
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#define DT_UNKNOWN 0
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#define DT_DIR 1
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#define DT_REG 2
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#define DT_LNK 3
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#define DTYPE(de) DT_UNKNOWN
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#endif
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/*
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* Environment variables transition.
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* We accept older names for now but warn.
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*/
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extern char *gitenv_bc(const char *);
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#define gitenv(e) (getenv(e) ? : gitenv_bc(e))
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/*
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* Basic data structures for the directory cache
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*/
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#define CACHE_SIGNATURE 0x44495243 /* "DIRC" */
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struct cache_header {
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unsigned int hdr_signature;
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unsigned int hdr_version;
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unsigned int hdr_entries;
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};
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/*
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* The "cache_time" is just the low 32 bits of the
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* time. It doesn't matter if it overflows - we only
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* check it for equality in the 32 bits we save.
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*/
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struct cache_time {
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unsigned int sec;
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unsigned int nsec;
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};
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/*
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* dev/ino/uid/gid/size are also just tracked to the low 32 bits
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* Again - this is just a (very strong in practice) heuristic that
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* the inode hasn't changed.
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*
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* We save the fields in big-endian order to allow using the
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* index file over NFS transparently.
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*/
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struct cache_entry {
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struct cache_time ce_ctime;
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struct cache_time ce_mtime;
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unsigned int ce_dev;
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unsigned int ce_ino;
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unsigned int ce_mode;
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unsigned int ce_uid;
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unsigned int ce_gid;
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unsigned int ce_size;
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unsigned char sha1[20];
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unsigned short ce_flags;
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char name[0];
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};
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#define CE_NAMEMASK (0x0fff)
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#define CE_STAGEMASK (0x3000)
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#define CE_STAGESHIFT 12
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#define create_ce_flags(len, stage) htons((len) | ((stage) << CE_STAGESHIFT))
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#define ce_namelen(ce) (CE_NAMEMASK & ntohs((ce)->ce_flags))
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#define ce_size(ce) cache_entry_size(ce_namelen(ce))
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#define ce_stage(ce) ((CE_STAGEMASK & ntohs((ce)->ce_flags)) >> CE_STAGESHIFT)
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#define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
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static inline unsigned int create_ce_mode(unsigned int mode)
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{
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if (S_ISLNK(mode))
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return htonl(S_IFLNK);
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return htonl(S_IFREG | ce_permissions(mode));
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}
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#define cache_entry_size(len) ((offsetof(struct cache_entry,name) + (len) + 8) & ~7)
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extern struct cache_entry **active_cache;
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extern unsigned int active_nr, active_alloc, active_cache_changed;
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#define GIT_DIR_ENVIRONMENT "GIT_DIR"
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#define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
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#define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
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#define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
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extern char *get_object_directory(void);
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extern char *get_index_file(void);
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#define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
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#define alloc_nr(x) (((x)+16)*3/2)
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/* Initialize and use the cache information */
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extern int read_cache(void);
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extern int write_cache(int newfd, struct cache_entry **cache, int entries);
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extern int cache_name_pos(const char *name, int namelen);
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#define ADD_CACHE_OK_TO_ADD 1 /* Ok to add */
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#define ADD_CACHE_OK_TO_REPLACE 2 /* Ok to replace file/directory */
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extern int add_cache_entry(struct cache_entry *ce, int option);
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extern int remove_cache_entry_at(int pos);
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extern int remove_file_from_cache(char *path);
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extern int ce_same_name(struct cache_entry *a, struct cache_entry *b);
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extern int ce_match_stat(struct cache_entry *ce, struct stat *st);
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extern int index_fd(unsigned char *sha1, int fd, struct stat *st);
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extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
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struct cache_file {
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struct cache_file *next;
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char lockfile[PATH_MAX];
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};
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extern int hold_index_file_for_update(struct cache_file *, const char *path);
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extern int commit_index_file(struct cache_file *);
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extern void rollback_index_file(struct cache_file *);
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#define MTIME_CHANGED 0x0001
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#define CTIME_CHANGED 0x0002
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#define OWNER_CHANGED 0x0004
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#define MODE_CHANGED 0x0008
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#define INODE_CHANGED 0x0010
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#define DATA_CHANGED 0x0020
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#define TYPE_CHANGED 0x0040
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/* Return a statically allocated filename matching the sha1 signature */
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extern char *sha1_file_name(const unsigned char *sha1);
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/* Read and unpack a sha1 file into memory, write memory to a sha1 file */
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extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
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extern int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size);
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extern int parse_sha1_header(char *hdr, char *type, unsigned long *sizep);
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extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
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extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
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extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
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extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
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/* Read a tree into the cache */
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extern int read_tree(void *buffer, unsigned long size, int stage);
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extern int write_sha1_from_fd(const unsigned char *sha1, int fd);
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extern int has_sha1_file(const unsigned char *sha1);
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/* Convert to/from hex/sha1 representation */
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extern int get_sha1(const char *str, unsigned char *sha1);
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extern int get_sha1_hex(const char *hex, unsigned char *sha1);
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extern char *sha1_to_hex(const unsigned char *sha1); /* static buffer result! */
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/* General helper functions */
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extern void usage(const char *err);
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extern void die(const char *err, ...);
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extern int error(const char *err, ...);
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extern int base_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
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extern int cache_name_compare(const char *name1, int len1, const char *name2, int len2);
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extern void *read_object_with_reference(const unsigned char *sha1,
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const char *required_type,
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unsigned long *size,
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unsigned char *sha1_ret);
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const char *show_date(unsigned long time, int timezone);
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void parse_date(char *date, char *buf, int bufsize);
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void datestamp(char *buf, int bufsize);
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static inline void *xmalloc(size_t size)
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{
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void *ret = malloc(size);
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if (!ret)
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die("Out of memory, malloc failed");
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return ret;
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}
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static inline void *xrealloc(void *ptr, size_t size)
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{
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void *ret = realloc(ptr, size);
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if (!ret)
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die("Out of memory, realloc failed");
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return ret;
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}
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static inline void *xcalloc(size_t nmemb, size_t size)
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{
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void *ret = calloc(nmemb, size);
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if (!ret)
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die("Out of memory, calloc failed");
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return ret;
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}
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#endif /* CACHE_H */
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