<?php
/* SVN FILE: $Id$ */

/**
 * Caching for Cake.
 * 
 * 
 *
 * PHP versions 4 and 5
 *
 * CakePHP :  Rapid Development Framework <http://www.cakephp.org/>
 * Copyright (c) 2005, CakePHP Authors/Developers
 *
 * Author(s): Michal Tatarynowicz aka Pies <tatarynowicz@gmail.com>
 *            Larry E. Masters aka PhpNut <nut@phpnut.com>
 *            Kamil Dzielinski aka Brego <brego.dk@gmail.com>
 *
 *  Licensed under The MIT License
 *  Redistributions of files must retain the above copyright notice.
 *
 * @filesource 
 * @author       CakePHP Authors/Developers
 * @copyright    Copyright (c) 2005, CakePHP Authors/Developers
 * @link         https://trac.cakephp.org/wiki/Authors Authors/Developers
 * @package      cake
 * @subpackage   cake.cake.libs
 * @since        CakePHP v 0.2.9
 * @version      $Revision$
 * @modifiedby   $LastChangedBy$
 * @lastmodified $Date$
 * @license      http://www.opensource.org/licenses/mit-license.php The MIT License
 */


/**
  * Included libraries.
  *
  */
uses(DS.'model'.DS.'model');

/**
 * Caching for Cake.
 * 
 * 
 *
 * @package    cake
 * @subpackage cake.cake.libs
 * @since      CakePHP v 0.2.9
 */
class Cache extends Model {

	/**
      * Identifier. Either an MD5 string or NULL.
      *
      * @var string
      */
	var $id = null;

	/**
      * Content container for cache data.
      *
      * @var unknown_type
      */
	var $data = null;

	/**
      * Content to be cached.
      *
      * @var unknown_type
      */
	var $for_caching = null;

	/**
      * Name of the database table used for caching.
      *
      * @var string
      */
	var $useTable = 'cache';

	/**
      * Constructor. Generates an md5'ed id for internal use. Calls the constructor on Model as well.
      *
      * @param unknown_type $id
      */
	function __construct ($id)
	{
		$this->id = (md5($id));
		parent::__construct($this->id);
	}

	/**
      * Returns this object's id after setting it. If called without parameters the current object's id is returned.
      *
      * @param unknown_type $id
      * @return unknown
      */
	function id ($id=null)
	{
		if (!$id) return $this->id;
		return ($this->id = $id);
	}

	/**
      * Store given content in cache database.
      *
      * @param string $content 		Content to keep in cache.
      * @param int $keep_for 		Number of seconds to keep data in cache.
      * @return boolean				Success
      */
	function remember ($content, $keep_for=CACHE_PAGES_FOR)
	{
		$data = addslashes($this->for_caching.$content);
		$expire = date("Y-m-d H:i:s",time()+($keep_for>0? $keep_for: 999999999));
		return $this->query("REPLACE {$this->useTable} (id,data,expire) VALUES ('{$this->id}', '{$data}', '{$expire}')");
	}

	/**
	  * Returns content from the Cache object itself, if the Cache object has a non-empty data property. 
	  * Else from the database cache.
 	  *
	  * @return unknown
  	  */
	function restore()
	{
		if (empty($this->data['data']))
		return $this->find("id='{$this->id}' AND expire>NOW()");

		return $this->data['data'];
	}

	/**
      * Returns true if the cache data property has current (non-stale) content for given id.
      *
      * @return boolean
      */
	function has()
	{
		return is_array($this->data = $this->find("id='{$this->id}' AND expire>NOW()"));
	}

	/**
      * Appends $string to the for_caching property of the Cache object.
      *
      * @param string $string
      */
	function append($string)
	{
		$this->for_caching .= $string;
	}

	/**
      * Clears the cache database table.
      *
      * @return unknown
      */
	function clear()
	{
		return $this->query("DELETE FROM {$this->useTable}");
	}
}

?>