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 /** @brief Call used by from cache_expire() */
88 static int expiry_callback(const char *key
, void *value
, void *u
) {
89 const struct cache_entry
*c
= value
;
90 const time_t *now
= u
;
97 /** @brief Expire the cache
99 * Called from time to time to expire cache entries. */
100 void cache_expire(void) {
105 hash_foreach(h
, expiry_callback
, &now
);
109 /** @brief Callback used by cache_clean() */
110 static int clean_callback(const char *key
, void *value
, void *u
) {
111 const struct cache_entry
*c
= value
;
112 const struct cache_type
*type
= u
;
114 if(!type
|| c
->type
== type
)
119 /** @brief Clean the cache
120 * @param type Pointer to type to clean
122 * Removes all entries of type @p type from the cache.
124 void cache_clean(const struct cache_type
*type
) {
126 hash_foreach(h
, clean_callback
, (void *)type
);
129 /** @brief Report cache size
131 * Returns the number of objects in the cache
133 size_t cache_count(void) {
134 return h ?
hash_count(h
) : 0;