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<?php
/**
* TXCache class file
*
* @author Wei Zhuo <weizhuo[at]gmail[dot]com>
* @link http://www.pradosoft.com/
* @copyright Copyright © 2005-2015 PradoSoft
* @license http://www.pradosoft.com/license/
* @package System.Caching
*/
/**
* TXCache class
*
* TXCache implements a cache application module based on {@link http://xcache.lighttpd.net/ xcache}.
*
* By definition, cache does not ensure the existence of a value
* even if it never expires. Cache is not meant to be an persistent storage.
*
* To use this module, the xcache PHP extension must be loaded and configured in the php.ini.
*
* Some usage examples of TXCache are as follows,
* <code>
* $cache=new TXCache; // TXCache may also be loaded as a Prado application module
* $cache->init(null);
* $cache->add('object',$object);
* $object2=$cache->get('object');
* </code>
*
* If loaded, TXCache will register itself with {@link TApplication} as the
* cache module. It can be accessed via {@link TApplication::getCache()}.
*
* TXCache may be configured in application configuration file as follows
* <code>
* <module id="cache" class="System.Caching.TXCache" />
* </code>
*
* @author Wei Zhuo <weizhuo[at]gmail[dot]com>
* @package System.Caching
* @since 3.1.1
*/
class TXCache extends TCache
{
/**
* Initializes this module.
* This method is required by the IModule interface.
* @param TXmlElement configuration for this module, can be null
* @throws TConfigurationException if xcache extension is not installed or not started, check your php.ini
*/
public function init($config)
{
if(!function_exists('xcache_isset'))
throw new TConfigurationException('xcache_extension_required');
$enabled = (int)ini_get('xcache.cacher') !== 0;
$var_size = (int)ini_get('xcache.var_size');
if(!($enabled && $var_size > 0))
throw new TConfigurationException('xcache_extension_not_enabled');
parent::init($config);
}
/**
* Retrieves a value from cache with a specified key.
* This is the implementation of the method declared in the parent class.
* @param string a unique key identifying the cached value
* @return string the value stored in cache, false if the value is not in the cache or expired.
*/
protected function getValue($key)
{
return xcache_isset($key) ? xcache_get($key) : false;
}
/**
* Stores a value identified by a key in cache.
* This is the implementation of the method declared in the parent class.
*
* @param string the key identifying the value to be cached
* @param string the value to be cached
* @param integer the number of seconds in which the cached value will expire. 0 means never expire.
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
protected function setValue($key,$value,$expire)
{
return xcache_set($key,$value,$expire);
}
/**
* Stores a value identified by a key into cache if the cache does not contain this key.
* This is the implementation of the method declared in the parent class.
*
* @param string the key identifying the value to be cached
* @param string the value to be cached
* @param integer the number of seconds in which the cached value will expire. 0 means never expire.
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
protected function addValue($key,$value,$expire)
{
return !xcache_isset($key) ? $this->setValue($key,$value,$expire) : false;
}
/**
* Deletes a value with the specified key from cache
* This is the implementation of the method declared in the parent class.
* @param string the key of the value to be deleted
* @return boolean if no error happens during deletion
*/
protected function deleteValue($key)
{
return xcache_unset($key);
}
/**
* Deletes all values from cache.
* Be careful of performing this operation if the cache is shared by multiple applications.
*/
public function flush()
{
for($i=0, $max=xcache_count(XC_TYPE_VAR); $i<$max; $i++)
{
if(xcache_clear_cache(XC_TYPE_VAR, $i)===false)
return false;
}
return true;
}
}
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