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

/**
 * Cache
 * 
 * Long description for file
 *
 * 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.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
 */


/**
  * Enter description here...
  *
  */
uses('model');

/**
 * Short description for class.
 * 
 * Long description for class
 *
 * @package    cake
 * @subpackage cake.libs
 * @since      CakePHP v 0.2.9
 */
class Cache extends Model {

/**
  * Identifier. Either an MD5 string or NULL.
  *
  * @var unknown_type
  */
   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 unknown_type
  */
   var $use_table = '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 no $id is given then $this->id is returned.
  *
  * @param unknown_type $id
  * @return unknown
  */
   function id ($id=null) 
   {
      if (!$id) return $this->id;
      return ($this->id = $id);
   }

/**
  * Save $content in cache for $keep_for seconds.
  *
  * @param string $content Content to keep in cache.
  * @param int $keep_for Number of seconds to keep data in cache.
  * @return unknown
  */
   function remember ($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->use_table} (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->use_table}");
   }
}

?>