2 * This file is part of DisOrder
3 * Copyright (C) 2006-2008 Richard Kettlewell
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 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 /** @file lib/cache.c @brief Object caching */
30 /** @brief The global cache */
33 /** @brief One cache entry */
35 /** @brief What type of object this is */
36 const struct cache_type *type;
38 /** @brief Pointer to object value */
41 /** @brief Time that object was inserted into cache */
45 /** @brief Return true if object @p c has expired */
46 static int expired(const struct cache_entry *c, time_t now) {
47 return now - c->birth > c->type->lifetime;
50 /** @brief Insert an object into the cache
51 * @param type Pointer to object type
52 * @param key Unique key
53 * @param value Pointer to value
55 void cache_put(const struct cache_type *type,
56 const char *key, const void *value) {
57 struct cache_entry *c;
60 h = hash_new(sizeof (struct cache_entry));
61 c = xmalloc(sizeof *c);
65 hash_add(h, key, c, HASH_INSERT_OR_REPLACE);
68 /** @brief Look up an object in the cache
69 * @param type Pointer to object type
70 * @param key Unique key
71 * @return Pointer to object value or NULL if not found
73 const void *cache_get(const struct cache_type *type, const char *key) {
74 const struct cache_entry *c;
77 && (c = hash_find(h, key))
79 && !expired(c, xtime(0)))
85 /** @brief Call used by from cache_expire() */
86 static int expiry_callback(const char *key, void *value, void *u) {
87 const struct cache_entry *c = value;
88 const time_t *now = u;
95 /** @brief Expire the cache
97 * Called from time to time to expire cache entries. */
98 void cache_expire(void) {
103 hash_foreach(h, expiry_callback, &now);
107 /** @brief Callback used by cache_clean() */
108 static int clean_callback(const char *key, void *value, void *u) {
109 const struct cache_entry *c = value;
110 const struct cache_type *type = u;
112 if(!type || c->type == type)
117 /** @brief Clean the cache
118 * @param type Pointer to type to clean
120 * Removes all entries of type @p type from the cache.
122 void cache_clean(const struct cache_type *type) {
124 hash_foreach(h, clean_callback, (void *)type);
127 /** @brief Report cache size
129 * Returns the number of objects in the cache
131 size_t cache_count(void) {
132 return h ? hash_count(h) : 0;