ZendDataCache.php 2.75 KB
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<?php
/**
 * @link http://www.yiiframework.com/
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 * @copyright Copyright (c) 2008 Yii Software LLC
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 * @license http://www.yiiframework.com/license/
 */

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namespace yii\caching;

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/**
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 * ZendDataCache provides Zend data caching in terms of an application component.
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 *
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 * To use this application component, the [Zend Data Cache PHP extension](http://www.zend.com/en/products/server/)
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 * must be loaded.
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 *
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 * See [[Cache]] for common cache operations that ZendDataCache supports.
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 *
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 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
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 */
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class ZendDataCache extends Cache
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{
	/**
	 * Retrieves a value from cache with a specified key.
	 * This is the implementation of the method declared in the parent class.
	 * @param string $key a unique key identifying the cached value
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	 * @return string|boolean the value stored in cache, false if the value is not in the cache or expired.
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	 */
	protected function getValue($key)
	{
		$result = zend_shm_cache_fetch($key);
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		return $result === null ? false : $result;
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	}

	/**
	 * Stores a value identified by a key in cache.
	 * This is the implementation of the method declared in the parent class.
	 *
	 * @param string $key the key identifying the value to be cached
	 * @param string $value the value to be cached
	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
	 * @return boolean true if the value is successfully stored into cache, false otherwise
	 */
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	protected function setValue($key, $value, $expire)
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	{
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		return zend_shm_cache_store($key, $value, $expire);
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	}

	/**
	 * 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 $key the key identifying the value to be cached
	 * @param string $value the value to be cached
	 * @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
	 * @return boolean true if the value is successfully stored into cache, false otherwise
	 */
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	protected function addValue($key, $value, $expire)
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	{
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		return zend_shm_cache_fetch($key) === null ? $this->setValue($key, $value, $expire) : false;
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	}

	/**
	 * Deletes a value with the specified key from cache
	 * This is the implementation of the method declared in the parent class.
	 * @param string $key the key of the value to be deleted
	 * @return boolean if no error happens during deletion
	 */
	protected function deleteValue($key)
	{
		return zend_shm_cache_delete($key);
	}

	/**
	 * Deletes all values from cache.
	 * This is the implementation of the method declared in the parent class.
	 * @return boolean whether the flush operation was successful.
	 */
	protected function flushValues()
	{
		return zend_shm_cache_clear();
	}
}