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 */
29 /** @brief The global cache */
32 /** @brief One cache entry */
34 /** @brief What type of object this is */
35 const struct cache_type *type;
37 /** @brief Pointer to object value */
40 /** @brief Time that object was inserted into cache */
44 /** @brief Return true if object @p c has expired */
45 static int expired(const struct cache_entry *c, time_t now) {
46 return now - c->birth > c->type->lifetime;
49 /** @brief Insert an object into the cache
50 * @param type Pointer to object type
51 * @param key Unique key
52 * @param value Pointer to value
54 void cache_put(const struct cache_type *type,
55 const char *key, const void *value) {
56 struct cache_entry *c;
59 h = hash_new(sizeof (struct cache_entry));
60 c = xmalloc(sizeof *c);
64 hash_add(h, key, c, HASH_INSERT_OR_REPLACE);
67 /** @brief Look up an object in the cache
68 * @param type Pointer to object type
69 * @param key Unique key
70 * @return Pointer to object value or NULL if not found
72 const void *cache_get(const struct cache_type *type, const char *key) {
73 const struct cache_entry *c;
76 && (c = hash_find(h, key))
78 && !expired(c, time(0)))
84 /** @brief Call used by from cache_expire() */
85 static int expiry_callback(const char *key, void *value, void *u) {
86 const struct cache_entry *c = value;
87 const time_t *now = u;
94 /** @brief Expire the cache
96 * Called from time to time to expire cache entries. */
97 void cache_expire(void) {
102 hash_foreach(h, expiry_callback, &now);
106 /** @brief Callback used by cache_clean() */
107 static int clean_callback(const char *key, void *value, void *u) {
108 const struct cache_entry *c = value;
109 const struct cache_type *type = u;
111 if(!type || c->type == type)
116 /** @brief Clean the cache
117 * @param type Pointer to type to clean
119 * Removes all entries of type @p type from the cache.
121 void cache_clean(const struct cache_type *type) {
123 hash_foreach(h, clean_callback, (void *)type);
126 /** @brief Report cache size
128 * Returns the number of objects in the cache
130 size_t cache_count(void) {
131 return h ? hash_count(h) : 0;