CodeIgniter Caching Class Subfolder

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package     CodeIgniter
 * @author      ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2006 - 2012 EllisLab, Inc.
 * @license     http://codeigniter.com/user_guide/license.html
 * @link        http://codeigniter.com
 * @since       Version 2.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * CodeIgniter Caching Class
 *
 * @package     CodeIgniter
 * @subpackage  Libraries
 * @category    Core
 * @author      ExpressionEngine Dev Team
 * @author      Valerii Kot
 * $this->cache->model('model name', 'model method', 'model param', 'subfolder/chache file name', time);
 * $this->cache->save('subfolder/chache file name', $data, time);
 * support subfolder/subfolder/subfolder/subfolder/subfolder/ ...
 * $this->cache->delete('subfolder/chache file name'); delete chache file
 * $this->cache->clean(); delete all cache
 * $this->cache->clean('subfolder'); delete all cache in subfolder
 * @link
 */
class CI_Cache extends CI_Driver_Library {

    protected $valid_drivers    = array(
        'cache_apc', 'cache_file', 'cache_memcached', 'cache_dummy'
    );

    protected $_cache_path      = NULL;     // Path of cache files (if file-based cache)
    protected $_adapter         = 'dummy';
    protected $_backup_driver;

    // ------------------------------------------------------------------------

    /**
     * Constructor
     *
     * @param array
     */
    public function __construct($config = array())
    {
        if ( ! empty($config))
        {
            $this->_initialize($config);
        }
    }

    // ------------------------------------------------------------------------

    /**
     * Get
     *
     * Look for a value in the cache.  If it exists, return the data
     * if not, return FALSE
     *
     * @param   string
     * @return  mixed       value that is stored/FALSE on failure
     */
    public function get($id)
    {
        return $this->{$this->_adapter}->get($id);
    }

    // ------------------------------------------------------------------------

    /**
     * Cache Save
     *
     * @param   string      Unique Key
     * @param   mixed       Data to store
     * @param   int         Length of time (in seconds) to cache the data
     *
     * @return  boolean     true on success/false on failure
     */
    public function save($id, $data, $ttl = 60)
    {
        if($this->_adapter == 'cache_file'){
            return $this->{$this->_adapter}->save($id, $data, $ttl);
        }else{
            $folder = explode('/', $id);
            if (count($folder) > 1 ) {
                $subfolder = '';
                for ($i=0; $i < (count($folder) - 1); $i++) {
                    $subfolder .= $folder[$i] . '/';
                }
                if (!is_dir('application/cache/'.$subfolder)) {
                    mkdir('./application/cache/'.$subfolder, 0777, TRUE);
                }
            }
            return $this->{$this->_adapter}->save($id, $data, $ttl);
        }
    }

    public function model($model, $method, $param = array(), $id, $ttl = 60)
    {
        if ($this->get($id)) {
            return $this->get($id);
        } else {
            $ci=& get_instance();
            $ci->load->model($model);
            $data = $ci->{$model}->{$method}($param);
            if ($this->save($id, $data, $ttl)) {
                return $data;
            } else {
                return FALSE;
            }
        }
    }

    // ------------------------------------------------------------------------

    /**
     * Delete from Cache
     *
     * @param   mixed       unique identifier of the item in the cache
     * @return  boolean     true on success/false on failure
     */
    public function delete($id)
    {
        return $this->{$this->_adapter}->delete($id);
    }

    // ------------------------------------------------------------------------

    /**
     * Clean the cache
     *
     * @return  boolean     false on failure/true on success
     */
    public function clean($folder = '')
    {
        if ($folder != '') {
            $ci=& get_instance();
            $ci->load->helper('file');
            return delete_files('application/cache/'.$folder, TRUE);
        }else{
            return $this->{$this->_adapter}->clean();
        }

    }

    // ------------------------------------------------------------------------

    /**
     * Cache Info
     *
     * @param   string      user/filehits
     * @return  mixed       array on success, false on failure
     */
    public function cache_info($type = 'user')
    {
        return $this->{$this->_adapter}->cache_info($type);
    }

    // ------------------------------------------------------------------------

    /**
     * Get Cache Metadata
     *
     * @param   mixed       key to get cache metadata on
     * @return  mixed       return value from child method
     */
    public function get_metadata($id)
    {
        return $this->{$this->_adapter}->get_metadata($id);
    }

    // ------------------------------------------------------------------------

    /**
     * Initialize
     *
     * Initialize class properties based on the configuration array.
     *
     * @param   array
     * @return  void
     */
    private function _initialize($config)
    {
        $default_config = array(
                'adapter',
                'memcached'
            );

        foreach ($default_config as $key)
        {
            if (isset($config[$key]))
            {
                $param = '_'.$key;

                $this->{$param} = $config[$key];
            }
        }

        if (isset($config['backup']))
        {
            if (in_array('cache_'.$config['backup'], $this->valid_drivers))
            {
                $this->_backup_driver = $config['backup'];
            }
        }
    }

    // ------------------------------------------------------------------------

    /**
     * Is the requested driver supported in this environment?
     *
     * @param   string  The driver to test.
     * @return  array
     */
    public function is_supported($driver)
    {
        static $support = array();

        if ( ! isset($support[$driver]))
        {
            $support[$driver] = $this->{$driver}->is_supported();
        }

        return $support[$driver];
    }

    // ------------------------------------------------------------------------

    /**
     * __get()
     *
     * @param   child
     * @return  object
     */
    public function __get($child)
    {
        $obj = parent::__get($child);

        if ( ! $this->is_supported($child))
        {
            $this->_adapter = $this->_backup_driver;
        }

        return $obj;
    }

    // ------------------------------------------------------------------------
}
// End Class

/* End of file Cache.php */
/* Location: ./system/libraries/Cache/Cache.php */