2 * This file is part of DisOrder
3 * Copyright (C) 2006 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 2 of the License, or
8 * (at your option) any later version.
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.
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
20 /** @file lib/cache.c @brief Object caching */
32 /** @brief The global cache */
35 /** @brief One cache entry */
37 /** @brief What type of object this is */
38 const struct cache_type *type;
40 /** @brief Pointer to object value */
43 /** @brief Time that object was inserted into cache */
47 /** @brief Return true if object @p c has expired */
48 static int expired(const struct cache_entry *c, time_t now) {
49 return now - c->birth > c->type->lifetime;
52 /** @brief Insert an object into the cache
53 * @param type Pointer to object type
54 * @param key Unique key
55 * @param value Pointer to value
57 void cache_put(const struct cache_type *type,
58 const char *key, const void *value) {
59 struct cache_entry *c;
62 h = hash_new(sizeof (struct cache_entry));
63 c = xmalloc(sizeof *c);
67 hash_add(h, key, c, HASH_INSERT_OR_REPLACE);
70 /** @brief Look up an object in the cache
71 * @param type Pointer to object type
72 * @param key Unique key
73 * @return Pointer to object value or NULL if not found
75 const void *cache_get(const struct cache_type *type, const char *key) {
76 const struct cache_entry *c;
79 && (c = hash_find(h, key))
81 && !expired(c, time(0)))
87 static int expiry_callback(const char *key, void *value, void *u) {
88 const struct cache_entry *c = value;
89 const time_t *now = u;
96 /** @brief Expire the cache
98 * Called from time to time to expire cache entries. */
99 void cache_expire(void) {
104 hash_foreach(h, expiry_callback, &now);
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;