<?php
/**
* MultiCache class class provides a convenient way to work with caches.
* It can use local file system, memcache or other external storage.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3.0 of the License, or (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*/
abstract class MultiCache {
/**
* Cache max size, bytes.
* If maxSize == -1 use cache driver specific value for cache max size.
*
* @var integer
*/
public $maxSize = 0;
/**
* Cache max items count.
*
* @var integer
*/
public $maxItemsCount = 0;
/**
* Cleans cache frequency factor.
*
* Clean cache operation will start randomly with random factor N
* if cache overflow.
*
* @var integer
*/
public $cleanCacheFactor = 10;
/**
* Gets data.
*
* @param mixed $key The key that will be associated with the item .
* @param mixed $default Default value.
*
* @return mixed Stored data.
*/
public abstract function get($key, $default = null);
/**
* Stores data.
*
* @param string $key The key that will be associated with the item.
* @param mixed $value The variable to store.
* @param integer $expire Expiration time of the item. Unix timestamp or
* number of seconds.
*/
public function set($key, $value, $expire = null) {
// Check cache limits
$err = null;
if (($m = $this->getMaxItemsCount()) && $this->getItemsCount() >= $m) {
$err = "Maximum items count attained!";
}
if (($m = $this->getMaxSize()) && $this->getSize() >= $m) {
$err = "Maximum items count attained!";
}
// Check error
if ($err != null) {
// Check clean cache factor
if ($this->cleanCacheFactor > 0 && mt_rand(0, $this->cleanCacheFactor - 1) == 0) {
$this->clean();
// Secondary check cache limits
if ((!($m = $this->getMaxItemsCount()) || $this->getItemsCount() < $m) &&
(!($m = $this->getMaxSize()) || $this->getSize() < $m))
{
return;
}
}
throw new Exception($err);
}
}
/**
* Removes data from the cache.
*
* @param string $key The key that will be associated with the item.
*/
public abstract function remove($key);
/**
* Removes all cached data.
*/
public abstract function removeAll();
/**
* Cleans expired cached data.
*/
public abstract function clean();
/**
* Gets items count.
*
* @return integer Items count
*/
public abstract function getItemsCount();
/**
* Gets cached data size.
*
* @return integer Cache size, bytes.
*/
public abstract function getSize();
/**
* Gets cache max size. If maxSize == -1 use cache driver specific value
* of cache max size.
*
* @return integer Cache maximum size, bytes.
*/
public function getMaxSize() {
return $this->maxSize >= 0 ? $this->maxSize : $this->getTotalMaxSize();
}
/**
* Gets total cache max size.
*
* @return integer Cache maximum size, bytes.
*/
public function getTotalMaxSize() {
return 0;
}
/**
* Gets max items count.
*
* @return integer Maximum items count.
*/
public function getMaxItemsCount() {
return $this->maxItemsCount;
}
}
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