1/*-
2 * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#ifndef __NSCD_CACHEPLCS_H__
30#define __NSCD_CACHEPLCS_H__
31
32#include <sys/queue.h>
33
34/* common policy definitions */
35#define CACHELIB_MAX_FREQUENCY 100
36
37/*
38 * cache_policy_item_ represents some abstract cache element in the policy
39 * queue. connected_item pointers to the corresponding cache_policy_item_ in
40 * another policy queue.
41 */
42struct cache_policy_item_ {
43	char	*key;
44    	size_t	key_size;
45
46	size_t	request_count;
47	struct timeval last_request_time;
48	struct timeval creation_time;
49
50	struct cache_policy_item_ *connected_item;
51};
52
53/*
54 * cache_policy_ represents an abstract policy queue. It can be customized by
55 * setting appropriate function pointers
56 */
57struct cache_policy_ {
58	struct cache_policy_item_* (*create_item_func)(void);
59	void (*destroy_item_func)(struct cache_policy_item_ *);
60
61	void (*add_item_func)(struct cache_policy_ *,
62		struct cache_policy_item_ *);
63	void (*remove_item_func)(struct cache_policy_ *,
64		struct cache_policy_item_ *);
65	void (*update_item_func)(struct cache_policy_ *,
66		struct cache_policy_item_ *);
67
68	struct cache_policy_item_ *(*get_first_item_func)(
69		struct cache_policy_ *);
70	struct cache_policy_item_ *(*get_last_item_func)(
71		struct cache_policy_ *);
72	struct cache_policy_item_ *(*get_next_item_func)(
73		struct cache_policy_ *, struct cache_policy_item_ *);
74	struct cache_policy_item_ *(*get_prev_item_func)(
75		struct cache_policy_ *, struct cache_policy_item_ *);
76};
77
78/*
79 * LFU cache policy item "inherited" from cache_policy_item_ structure
80 */
81struct cache_lfu_policy_item_ {
82	struct cache_policy_item_ parent_data;
83	int	frequency;
84
85	TAILQ_ENTRY(cache_lfu_policy_item_) entries;
86};
87
88TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
89
90/*
91 * LFU policy queue "inherited" from cache_policy_.
92 */
93struct cache_lfu_policy_ {
94	struct cache_policy_ parent_data;
95	struct cache_lfu_policy_group_ groups[CACHELIB_MAX_FREQUENCY];
96};
97
98/*
99 * LRU and FIFO policies item "inherited" from cache_policy_item_
100 */
101struct cache_queue_policy_item_ {
102	struct cache_policy_item_ parent_data;
103	TAILQ_ENTRY(cache_queue_policy_item_) entries;
104};
105
106/*
107 * LRU and FIFO policies "inherited" from cache_policy_
108 */
109struct cache_queue_policy_ {
110	struct cache_policy_ parent_data;
111	TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
112};
113
114typedef struct cache_queue_policy_ cache_fifo_policy_;
115typedef struct cache_queue_policy_ cache_lru_policy_;
116
117/* fifo policy routines */
118struct cache_policy_ *init_cache_fifo_policy(void);
119void destroy_cache_fifo_policy(struct cache_policy_ *);
120
121/* lru policy routines */
122struct cache_policy_ *init_cache_lru_policy(void);
123void destroy_cache_lru_policy(struct cache_policy_ *);
124
125/* lfu policy routines */
126struct cache_policy_ *init_cache_lfu_policy(void);
127void destroy_cache_lfu_policy(struct cache_policy_ *);
128
129#endif
130