chiark / gitweb /
Fiddle with CSS+HTML in effort to get more consistent buttons
[disorder] / lib / cache.c
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460b9539 1/*
2 * This file is part of DisOrder
5aff007d 3 * Copyright (C) 2006-2008 Richard Kettlewell
460b9539 4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
14ad73b9 20/** @file lib/cache.c @brief Object caching */
460b9539 21
05b75f8d 22#include "common.h"
460b9539 23
24#include <time.h>
25
26#include "hash.h"
27#include "mem.h"
28#include "log.h"
29#include "cache.h"
30
d7b6f0d1 31/** @brief The global cache */
460b9539 32static hash *h;
33
d7b6f0d1 34/** @brief One cache entry */
460b9539 35struct cache_entry {
d7b6f0d1 36 /** @brief What type of object this is */
460b9539 37 const struct cache_type *type;
d7b6f0d1 38
39 /** @brief Pointer to object value */
460b9539 40 const void *value;
d7b6f0d1 41
42 /** @brief Time that object was inserted into cache */
460b9539 43 time_t birth;
44};
45
d7b6f0d1 46/** @brief Return true if object @p c has expired */
460b9539 47static int expired(const struct cache_entry *c, time_t now) {
48 return now - c->birth > c->type->lifetime;
49}
50
d7b6f0d1 51/** @brief Insert an object into the cache
52 * @param type Pointer to object type
53 * @param key Unique key
54 * @param value Pointer to value
55 */
460b9539 56void cache_put(const struct cache_type *type,
57 const char *key, const void *value) {
58 struct cache_entry *c;
59
60 if(!h)
61 h = hash_new(sizeof (struct cache_entry));
62 c = xmalloc(sizeof *c);
63 c->type = type;
64 c->value = value;
65 time(&c->birth);
66 hash_add(h, key, c, HASH_INSERT_OR_REPLACE);
67}
68
d7b6f0d1 69/** @brief Look up an object in the cache
70 * @param type Pointer to object type
71 * @param key Unique key
72 * @return Pointer to object value or NULL if not found
73 */
460b9539 74const void *cache_get(const struct cache_type *type, const char *key) {
75 const struct cache_entry *c;
76
77 if(h
78 && (c = hash_find(h, key))
79 && c->type == type
80 && !expired(c, time(0)))
81 return c->value;
82 else
83 return 0;
84}
85
0e4472a0 86/** @brief Call used by from cache_expire() */
460b9539 87static int expiry_callback(const char *key, void *value, void *u) {
88 const struct cache_entry *c = value;
89 const time_t *now = u;
90
91 if(expired(c, *now))
92 hash_remove(h, key);
93 return 0;
94}
95
d7b6f0d1 96/** @brief Expire the cache
97 *
98 * Called from time to time to expire cache entries. */
460b9539 99void cache_expire(void) {
100 time_t now;
101
102 if(h) {
103 time(&now);
104 hash_foreach(h, expiry_callback, &now);
105 }
106}
107
0e4472a0 108/** @brief Callback used by cache_clean() */
460b9539 109static int clean_callback(const char *key, void *value, void *u) {
110 const struct cache_entry *c = value;
111 const struct cache_type *type = u;
112
113 if(!type || c->type == type)
114 hash_remove(h, key);
115 return 0;
116}
117
d7b6f0d1 118/** @brief Clean the cache
119 * @param type Pointer to type to clean
120 *
121 * Removes all entries of type @p type from the cache.
122 */
460b9539 123void cache_clean(const struct cache_type *type) {
124 if(h)
125 hash_foreach(h, clean_callback, (void *)type);
126}
127
d7b6f0d1 128/** @brief Report cache size
129 *
130 * Returns the number of objects in the cache
131 */
0b7c8909 132size_t cache_count(void) {
133 return h ? hash_count(h) : 0;
134}
135
460b9539 136/*
137Local Variables:
138c-basic-offset:2
139comment-column:40
140fill-column:79
141indent-tabs-mode:nil
142End:
143*/