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
27struct 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
35struct 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
45struct 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
56struct 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
67enum {
68	CACHE_FREE = 1,
69	CACHE_NOHASH = 2
70} ;
71
72typedef int (*cache_compare)(const struct CACHED_GENERIC *cached,
73				const struct CACHED_GENERIC *item);
74typedef void (*cache_free)(const struct CACHED_GENERIC *cached);
75typedef int (*cache_hash)(const struct CACHED_GENERIC *cached);
76
77struct HASH_ENTRY {
78	struct HASH_ENTRY *next;
79	struct CACHED_GENERIC *entry;
80} ;
81
82struct 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
102struct CACHED_GENERIC *ntfs_fetch_cache(struct CACHE_HEADER *cache,
103			const struct CACHED_GENERIC *wanted,
104			cache_compare compare);
105struct CACHED_GENERIC *ntfs_enter_cache(struct CACHE_HEADER *cache,
106			const struct CACHED_GENERIC *item,
107			cache_compare compare);
108int ntfs_invalidate_cache(struct CACHE_HEADER *cache,
109			const struct CACHED_GENERIC *item,
110			cache_compare compare, int flags);
111int ntfs_remove_cache(struct CACHE_HEADER *cache,
112			struct CACHED_GENERIC *item, int flags);
113
114void ntfs_create_lru_caches(ntfs_volume *vol);
115void ntfs_free_lru_caches(ntfs_volume *vol);
116
117#endif /* _NTFS_CACHE_H_ */
118
119