path: root/include/ntfs-3g/cache.h (plain)
blob: 67c332518bfd60911251795587580a6f850b337a

1	/*
2	* cache.h : deal with indexed LRU caches
3	*
4	* Copyright (c) 2008-2009 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	void *fixed[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	/* above fields must match "struct CACHED_GENERIC" */
41	u64 inum;
42	} ;
43
44	struct CACHED_NIDATA {
45	struct CACHED_NIDATA *next;
46	struct CACHED_NIDATA *previous;
47	const char *pathname; /* not used */
48	size_t varsize; /* not used */
49	/* above fields must match "struct CACHED_GENERIC" */
50	u64 inum;
51	ntfs_inode *ni;
52	} ;
53
54	struct CACHED_LOOKUP {
55	struct CACHED_LOOKUP *next;
56	struct CACHED_LOOKUP *previous;
57	const char *name;
58	size_t namesize;
59	/* above fields must match "struct CACHED_GENERIC" */
60	u64 parent;
61	u64 inum;
62	} ;
63
64	enum {
65	CACHE_FREE = 1,
66	CACHE_NOHASH = 2
67	} ;
68
69	typedef int (*cache_compare)(const struct CACHED_GENERIC *cached,
70	const struct CACHED_GENERIC *item);
71	typedef void (*cache_free)(const struct CACHED_GENERIC *cached);
72	typedef int (*cache_hash)(const struct CACHED_GENERIC *cached);
73
74	struct HASH_ENTRY {
75	struct HASH_ENTRY *next;
76	struct CACHED_GENERIC *entry;
77	} ;
78
79	struct CACHE_HEADER {
80	const char *name;
81	struct CACHED_GENERIC *most_recent_entry;
82	struct CACHED_GENERIC *oldest_entry;
83	struct CACHED_GENERIC *free_entry;
84	struct HASH_ENTRY *free_hash;
85	struct HASH_ENTRY **first_hash;
86	cache_free dofree;
87	cache_hash dohash;
88	unsigned long reads;
89	unsigned long writes;
90	unsigned long hits;
91	int fixed_size;
92	int max_hash;
93	struct CACHED_GENERIC entry[0];
94	} ;
95
96	/* cast to generic, avoiding gcc warnings */
97	#define GENERIC(pstr) ((const struct CACHED_GENERIC*)(const void*)(pstr))
98
99	struct CACHED_GENERIC *ntfs_fetch_cache(struct CACHE_HEADER *cache,
100	const struct CACHED_GENERIC *wanted,
101	cache_compare compare);
102	struct CACHED_GENERIC *ntfs_enter_cache(struct CACHE_HEADER *cache,
103	const struct CACHED_GENERIC *item,
104	cache_compare compare);
105	int ntfs_invalidate_cache(struct CACHE_HEADER *cache,
106	const struct CACHED_GENERIC *item,
107	cache_compare compare, int flags);
108	int ntfs_remove_cache(struct CACHE_HEADER *cache,
109	struct CACHED_GENERIC *item, int flags);
110
111	void ntfs_create_lru_caches(ntfs_volume *vol);
112	void ntfs_free_lru_caches(ntfs_volume *vol);
113
114	#endif /* _NTFS_CACHE_H_ */
115
116