include/ntfs-3g/cache.h

   1 /*
   2  * cache.h : deal with indexed LRU caches
   3  *
   4  * Copyright (c) 2008-2010 Jean-Pierre Andre
   5  *
   6  * This program/include file is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as published
   8  * by the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program/include file is distributed in the hope that it will be
  12  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program (in the main directory of the NTFS-3G
  18  * distribution in the file COPYING); if not, write to the Free Software
  19  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #ifndef _NTFS_CACHE_H_
  23 #define _NTFS_CACHE_H_
  24
  25 #include "volume.h"
  26
  27 struct CACHED_GENERIC {
  28         struct CACHED_GENERIC *next;
  29         struct CACHED_GENERIC *previous;
  30         void *variable;
  31         size_t varsize;
  32         union ALIGNMENT payload[0];
  33 } ;
  34
  35 struct CACHED_INODE {
  36         struct CACHED_INODE *next;
  37         struct CACHED_INODE *previous;
  38         const char *pathname;
  39         size_t varsize;
  40         union ALIGNMENT payload[0];
  41                 /* above fields must match "struct CACHED_GENERIC" */
  42         u64 inum;
  43 } ;
  44
  45 struct CACHED_NIDATA {
  46         struct CACHED_NIDATA *next;
  47         struct CACHED_NIDATA *previous;
  48         const char *pathname;   /* not used */
  49         size_t varsize;         /* not used */
  50         union ALIGNMENT payload[0];
  51                 /* above fields must match "struct CACHED_GENERIC" */
  52         u64 inum;
  53         ntfs_inode *ni;
  54 } ;
  55
  56 struct CACHED_LOOKUP {
  57         struct CACHED_LOOKUP *next;
  58         struct CACHED_LOOKUP *previous;
  59         const char *name;
  60         size_t namesize;
  61         union ALIGNMENT payload[0];
  62                 /* above fields must match "struct CACHED_GENERIC" */
  63         u64 parent;
  64         u64 inum;
  65 } ;
  66
  67 enum {
  68         CACHE_FREE = 1,
  69         CACHE_NOHASH = 2
  70 } ;
  71
  72 typedef int (*cache_compare)(const struct CACHED_GENERIC *cached,
  73                                 const struct CACHED_GENERIC *item);
  74 typedef void (*cache_free)(const struct CACHED_GENERIC *cached);
  75 typedef int (*cache_hash)(const struct CACHED_GENERIC *cached);
  76
  77 struct HASH_ENTRY {
  78         struct HASH_ENTRY *next;
  79         struct CACHED_GENERIC *entry;
  80 } ;
  81
  82 struct CACHE_HEADER {
  83         const char *name;
  84         struct CACHED_GENERIC *most_recent_entry;
  85         struct CACHED_GENERIC *oldest_entry;
  86         struct CACHED_GENERIC *free_entry;
  87         struct HASH_ENTRY *free_hash;
  88         struct HASH_ENTRY **first_hash;
  89         cache_free dofree;
  90         cache_hash dohash;
  91         unsigned long reads;
  92         unsigned long writes;
  93         unsigned long hits;
  94         int fixed_size;
  95         int max_hash;
  96         struct CACHED_GENERIC entry[0];
  97 } ;
  98
  99         /* cast to generic, avoiding gcc warnings */
 100 #define GENERIC(pstr) ((const struct CACHED_GENERIC*)(const void*)(pstr))
 101
 102 struct CACHED_GENERIC *ntfs_fetch_cache(struct CACHE_HEADER *cache,
 103                         const struct CACHED_GENERIC *wanted,
 104                         cache_compare compare);
 105 struct CACHED_GENERIC *ntfs_enter_cache(struct CACHE_HEADER *cache,
 106                         const struct CACHED_GENERIC *item,
 107                         cache_compare compare);
 108 int ntfs_invalidate_cache(struct CACHE_HEADER *cache,
 109                         const struct CACHED_GENERIC *item,
 110                         cache_compare compare, int flags);
 111 int ntfs_remove_cache(struct CACHE_HEADER *cache,
 112                         struct CACHED_GENERIC *item, int flags);
 113
 114 void ntfs_create_lru_caches(ntfs_volume *vol);
 115 void ntfs_free_lru_caches(ntfs_volume *vol);
 116
 117 #endif /* _NTFS_CACHE_H_ */
 118