<?php
  /**
   * Container for all Memcache-based cache methods. Inherits additional methods from <CacheCore>. Adheres
   * to the ICacheCore interface.
   *
   * @version 2012.04.17
   * @copyright 2006-2012 Ryan Parman
   * @copyright 2006-2010 Foleeo, Inc.
   * @copyright 2012 Amazon.com, Inc. or its affiliates.
   * @copyright 2008-2010 Contributors
   * @license http://opensource.org/licenses/bsd-license.php Simplified BSD License
   * @link http://github.com/skyzyx/cachecore CacheCore
   * @link http://getcloudfusion.com CloudFusion
   * @link http://php.net/memcache Memcache
   * @link http://php.net/memcached Memcached
   */
  class CacheMC extends CacheCore implements ICacheCore
  {
  	/**
  	 * Holds the Memcache object.
  	 */
  	var $memcache = null;
  
  	/**
  	 * Whether the Memcached extension is being used (as opposed to Memcache).
  	 */
  	var $is_memcached = false;
  
  
  	/*%******************************************************************************************%*/
  	// CONSTRUCTOR
  
  	/**
  	 * Constructs a new instance of this class.
  	 *
  	 * @param string $name (Required) A name to uniquely identify the cache object.
  	 * @param string $location (Optional) The location to store the cache object in. This may vary by cache method. The default value is NULL.
  	 * @param integer $expires (Optional) The number of seconds until a cache object is considered stale. The default value is 0.
  	 * @param boolean $gzip (Optional) Whether data should be gzipped before being stored. The default value is true.
  	 * @return object Reference to the cache object.
  	 */
  	public function __construct($name, $location = null, $expires = 0, $gzip = true)
  	{
  		parent::__construct($name, null, $expires, $gzip);
  		$this->id = $this->name;
  
  		// Prefer Memcached over Memcache.
  		if (class_exists('Memcached'))
  		{
  			$this->memcache = new Memcached();
  			$this->is_memcached = true;
  		}
  		elseif (class_exists('Memcache'))
  		{
  			$this->memcache = new Memcache();
  		}
  		else
  		{
  			return false;
  		}
  
  		// Enable compression, if available
  		if ($this->gzip)
  		{
  			if ($this->is_memcached)
  			{
  				$this->memcache->setOption(Memcached::OPT_COMPRESSION, true);
  			}
  			else
  			{
  				$this->gzip = MEMCACHE_COMPRESSED;
  			}
  		}
  
  		// Process Memcached servers.
  		if (isset($location) && sizeof($location) > 0)
  		{
  			foreach ($location as $loc)
  			{
  				if (isset($loc['port']) && !empty($loc['port']))
  				{
  					$this->memcache->addServer($loc['host'], $loc['port']);
  				}
  				else
  				{
  					$this->memcache->addServer($loc['host'], 11211);
  				}
  			}
  		}
  
  		return $this;
  	}
  
  	/**
  	 * Creates a new cache.
  	 *
  	 * @param mixed $data (Required) The data to cache.
  	 * @return boolean Whether the operation was successful.
  	 */
  	public function create($data)
  	{
  		if ($this->is_memcached)
  		{
  			return $this->memcache->set($this->id, $data, $this->expires);
  		}
  		return $this->memcache->set($this->id, $data, $this->gzip, $this->expires);
  	}
  
  	/**
  	 * Reads a cache.
  	 *
  	 * @return mixed Either the content of the cache object, or boolean `false`.
  	 */
  	public function read()
  	{
  		if ($this->is_memcached)
  		{
  			return $this->memcache->get($this->id);
  		}
  		return $this->memcache->get($this->id, $this->gzip);
  	}
  
  	/**
  	 * Updates an existing cache.
  	 *
  	 * @param mixed $data (Required) The data to cache.
  	 * @return boolean Whether the operation was successful.
  	 */
  	public function update($data)
  	{
  		if ($this->is_memcached)
  		{
  			return $this->memcache->replace($this->id, $data, $this->expires);
  		}
  		return $this->memcache->replace($this->id, $data, $this->gzip, $this->expires);
  	}
  
  	/**
  	 * Deletes a cache.
  	 *
  	 * @return boolean Whether the operation was successful.
  	 */
  	public function delete()
  	{
  		return $this->memcache->delete($this->id);
  	}
  
  	/**
  	 * Implemented here, but always returns `false`. Memcache manages its own expirations.
  	 *
  	 * @return boolean Whether the cache is expired or not.
  	 */
  	public function is_expired()
  	{
  		return false;
  	}
  
  	/**
  	 * Implemented here, but always returns `false`. Memcache manages its own expirations.
  	 *
  	 * @return mixed Either the Unix time stamp of the cache creation, or boolean `false`.
  	 */
  	public function timestamp()
  	{
  		return false;
  	}
  
  	/**
  	 * Implemented here, but always returns `false`. Memcache manages its own expirations.
  	 *
  	 * @return boolean Whether the operation was successful.
  	 */
  	public function reset()
  	{
  		return false;
  	}
  }
  
  
  /*%******************************************************************************************%*/
  // EXCEPTIONS
  
  class CacheMC_Exception extends CacheCore_Exception {}