source: sourcecode/system/libraries/Driver.php @ 1

<?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 - 2012, 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;

        // The first time a child is used it won't exist, so we instantiate it
        // subsequents calls will go straight to the proper child.
        function __get($child)
        {
                if ( ! isset($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;
                                                }
                                        }
                                }

                                // 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 */