/*
* This file is part of DisOrder
* Copyright (C) 2006-2008 Richard Kettlewell
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
/** @file lib/cache.c @brief Object caching */
#include "common.h"
#include
#include "hash.h"
#include "mem.h"
#include "log.h"
#include "cache.h"
/** @brief The global cache */
static hash *h;
/** @brief One cache entry */
struct cache_entry {
/** @brief What type of object this is */
const struct cache_type *type;
/** @brief Pointer to object value */
const void *value;
/** @brief Time that object was inserted into cache */
time_t birth;
};
/** @brief Return true if object @p c has expired */
static int expired(const struct cache_entry *c, time_t now) {
return now - c->birth > c->type->lifetime;
}
/** @brief Insert an object into the cache
* @param type Pointer to object type
* @param key Unique key
* @param value Pointer to value
*/
void cache_put(const struct cache_type *type,
const char *key, const void *value) {
struct cache_entry *c;
if(!h)
h = hash_new(sizeof (struct cache_entry));
c = xmalloc(sizeof *c);
c->type = type;
c->value = value;
time(&c->birth);
hash_add(h, key, c, HASH_INSERT_OR_REPLACE);
}
/** @brief Look up an object in the cache
* @param type Pointer to object type
* @param key Unique key
* @return Pointer to object value or NULL if not found
*/
const void *cache_get(const struct cache_type *type, const char *key) {
const struct cache_entry *c;
if(h
&& (c = hash_find(h, key))
&& c->type == type
&& !expired(c, time(0)))
return c->value;
else
return 0;
}
/** @brief Call used by from cache_expire() */
static int expiry_callback(const char *key, void *value, void *u) {
const struct cache_entry *c = value;
const time_t *now = u;
if(expired(c, *now))
hash_remove(h, key);
return 0;
}
/** @brief Expire the cache
*
* Called from time to time to expire cache entries. */
void cache_expire(void) {
time_t now;
if(h) {
time(&now);
hash_foreach(h, expiry_callback, &now);
}
}
/** @brief Callback used by cache_clean() */
static int clean_callback(const char *key, void *value, void *u) {
const struct cache_entry *c = value;
const struct cache_type *type = u;
if(!type || c->type == type)
hash_remove(h, key);
return 0;
}
/** @brief Clean the cache
* @param type Pointer to type to clean
*
* Removes all entries of type @p type from the cache.
*/
void cache_clean(const struct cache_type *type) {
if(h)
hash_foreach(h, clean_callback, (void *)type);
}
/** @brief Report cache size
*
* Returns the number of objects in the cache
*/
size_t cache_count(void) {
return h ? hash_count(h) : 0;
}
/*
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*/