system/libraries/Driver.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		EllisLab Dev Team
 * @copyright	Copyright (c) 2006 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

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

/**
 * CodeIgniter Driver Library Class
 *
 * This class enables you to create "Driver" libraries that add runtime ability
 * to extend the capabilities of a class via additional driver objects
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Libraries
 * @author		EllisLab Dev Team
 * @link
 */
class CI_Driver_Library {

	protected $valid_drivers	= array();
	protected $lib_name;

    /**
     * Get magic method
     *
	 * The first time a child is used it won't exist, so we instantiate it
	 * subsequents calls will go straight to the proper child.
     *
     * @param   string  Child class name
     * @return  object  Child class
     */
	public function __get($child)
	{
        // Try to load the driver
		return load_driver($child);
    }

    /**
     * Load driver
     *
	 * Separate load_driver call to support explicit driver load by library or user
     *
     * @param   string  Child class name
     * @return  object  Child class
     */
	public function load_driver($child)
	{
		if ( ! isset($this->lib_name))
		{
			$this->lib_name = get_class($this);
		}

		// The class will be prefixed with the parent lib
		$child_class = $this->lib_name.'_'.$child;
	
		// Remove the CI_ prefix and lowercase
		$lib_name = ucfirst(strtolower(str_replace('CI_', '', $this->lib_name)));
		$driver_name = strtolower(str_replace('CI_', '', $child_class));
		
		if (in_array($driver_name, array_map('strtolower', $this->valid_drivers)))
		{
			// check and see if the driver is in a separate file
			if ( ! class_exists($child_class))
			{
				// check application path first
				foreach (get_instance()->load->get_package_paths(TRUE) as $path)
				{
					// loves me some nesting!
					foreach (array(ucfirst($driver_name), $driver_name) as $class)
					{
						$filepath = $path.'libraries/'.$lib_name.'/drivers/'.$class.'.php';

						if (file_exists($filepath))
						{
							include_once $filepath;
							break 2;
						}
					}
				}

				// it's a valid driver, but the file simply can't be found
				if ( ! class_exists($child_class))
				{
					log_message('error', "Unable to load the requested driver: ".$child_class);
					show_error("Unable to load the requested driver: ".$child_class);
				}
			}

			$obj = new $child_class;
			$obj->decorate($this);
			$this->$child = $obj;
			return $this->$child;
		}

		// The requested driver isn't valid!
		log_message('error', 'Invalid driver requested: '.$child_class);
		show_error('Invalid driver requested: '.$child_class);
	}
}
// END CI_Driver_Library CLASS


/**
 * CodeIgniter Driver Class
 *
 * This class enables you to create drivers for a Library based on the Driver Library.
 * It handles the drivers' access to the parent library
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Libraries
 * @author		EllisLab Dev Team
 * @link
 */
class CI_Driver {
	protected $parent;

	private $methods = array();
	private $properties = array();

	private static $reflections = array();

	/**
	 * Decorate
	 *
	 * Decorates the child with the parent driver lib's methods and properties
	 *
	 * @param	object
	 * @return	void
	 */
	public function decorate($parent)
	{
		$this->parent = $parent;

		// Lock down attributes to what is defined in the class
		// and speed up references in magic methods

		$class_name = get_class($parent);

		if ( ! isset(self::$reflections[$class_name]))
		{
			$r = new ReflectionObject($parent);

			foreach ($r->getMethods() as $method)
			{
				if ($method->isPublic())
				{
					$this->methods[] = $method->getName();
				}
			}

			foreach ($r->getProperties() as $prop)
			{
				if ($prop->isPublic())
				{
					$this->properties[] = $prop->getName();
				}
			}

			self::$reflections[$class_name] = array($this->methods, $this->properties);
		}
		else
		{
			list($this->methods, $this->properties) = self::$reflections[$class_name];
		}
	}

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

	/**
	 * __call magic method
	 *
	 * Handles access to the parent driver library's methods
	 *
	 * @access	public
	 * @param	string
	 * @param	array
	 * @return	mixed
	 */
	public function __call($method, $args = array())
	{
		if (in_array($method, $this->methods))
		{
			return call_user_func_array(array($this->parent, $method), $args);
		}

		$trace = debug_backtrace();
		_exception_handler(E_ERROR, "No such method '{$method}'", $trace[1]['file'], $trace[1]['line']);
		exit;
	}

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

	/**
	 * __get magic method
	 *
	 * Handles reading of the parent driver library's properties
	 *
	 * @param	string
	 * @return	mixed
	 */
	public function __get($var)
	{
		if (in_array($var, $this->properties))
		{
			return $this->parent->$var;
		}
	}

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

	/**
	 * __set magic method
	 *
	 * Handles writing to the parent driver library's properties
	 *
	 * @param	string
	 * @param	array
	 * @return	mixed
	 */
	public function __set($var, $val)
	{
		if (in_array($var, $this->properties))
		{
			$this->parent->$var = $val;
		}
	}

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

}
// END CI_Driver CLASS

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