/www/slight

<?php

/**

 * Flight: An extensible micro-framework.

 *

 * @copyright   Copyright (c) 2011, Mike Cao <mike@mikecao.com>

 * @license     MIT, http://flightphp.com/license

 */

namespace flight\core;

/**

 * The Dispatcher class is responsible for dispatching events. Events

 * are simply aliases for class methods or functions. The Dispatcher

 * allows you to hook other functions to an event that can modify the

 * input parameters and/or the output.

 */

class Dispatcher {

    /**

     * Mapped events.

     *

     * @var array

     */

    protected $events = array();

    /**

     * Method filters.

     *

     * @var array

     */

    protected $filters = array();

    /**

     * Dispatches an event.

     *

     * @param string $name Event name

     * @param array $params Callback parameters

     * @return string Output of callback

     */

    public function run($name, array $params = array()) {

        $output = '';

        // Run pre-filters

        if (!empty($this->filters[$name]['before'])) {

            $this->filter($this->filters[$name]['before'], $params, $output);

        }

        // Run requested method

        $output = $this->execute($this->get($name), $params);

        // Run post-filters

        if (!empty($this->filters[$name]['after'])) {

            $this->filter($this->filters[$name]['after'], $params, $output);

        }

        return $output;

    }

    /**

     * Assigns a callback to an event.

     *

     * @param string $name Event name

     * @param callback $callback Callback function

     */

    public function set($name, $callback) {

        $this->events[$name] = $callback;

    }

    /**

     * Gets an assigned callback.

     *

     * @param string $name Event name

     * @return callback $callback Callback function

     */

    public function get($name) {

        return isset($this->events[$name]) ? $this->events[$name] : null;

    }

    /**

     * Checks if an event has been set.

     *

     * @param string $name Event name

     * @return bool Event status

     */

    public function has($name) {

        return isset($this->events[$name]);

    }

    /**

     * Clears an event. If no name is given,

     * all events are removed.

     *

     * @param string $name Event name

     */

    public function clear($name = null) {

        if ($name !== null) {

            unset($this->events[$name]);

            unset($this->filters[$name]);

        }

        else {

            $this->events = array();

            $this->filters = array();

        }

    }

    /**

     * Hooks a callback to an event.

     *

     * @param string $name Event name

     * @param string $type Filter type

     * @param callback $callback Callback function

     */

    public function hook($name, $type, $callback) {

        $this->filters[$name][$type][] = $callback;

    }

    /**

     * Executes a chain of method filters.

     *

     * @param array $filters Chain of filters

     * @param array $params Method parameters

     * @param mixed $output Method output

     */

    public function filter($filters, &$params, &$output) {

        $args = array(&$params, &$output);

        foreach ($filters as $callback) {

            $continue = $this->execute($callback, $args);

            if ($continue === false) break;

        }

    }

    /**

     * Executes a callback function.

     *

     * @param callback $callback Callback function

     * @param array $params Function parameters

     * @return mixed Function results

     * @throws \Exception

     */

    public static function execute($callback, array &$params = array()) {

        if (is_callable($callback)) {

            return is_array($callback) ?

                self::invokeMethod($callback, $params) :

                self::callFunction($callback, $params);

        }

        else {

            throw new \Exception('Invalid callback specified.');

        }

    }

    /**

     * Calls a function.

     *

     * @param string $func Name of function to call

     * @param array $params Function parameters

     * @return mixed Function results

     */

    public static function callFunction($func, array &$params = array()) {

        switch (count($params)) {

            case 0:

                return $func();

            case 1:

                return $func($params[0]);

            case 2:

                return $func($params[0], $params[1]);

            case 3:

                return $func($params[0], $params[1], $params[2]);

            case 4:

                return $func($params[0], $params[1], $params[2], $params[3]);

            case 5:

                return $func($params[0], $params[1], $params[2], $params[3], $params[4]);

            default:

                return call_user_func_array($func, $params);

        }

    }

    /**

     * Invokes a method.

     *

     * @param mixed $func Class method

     * @param array $params Class method parameters

     * @return mixed Function results

     */

    public static function invokeMethod($func, array &$params = array()) {

        list($class, $method) = $func;

		$instance = is_object($class);

        switch (count($params)) {

            case 0:

                return ($instance) ?

                    $class->$method() :

                    $class::$method();

            case 1:

                return ($instance) ?

                    $class->$method($params[0]) :

                    $class::$method($params[0]);

            case 2:

                return ($instance) ?

                    $class->$method($params[0], $params[1]) :

                    $class::$method($params[0], $params[1]);

            case 3:

                return ($instance) ?

                    $class->$method($params[0], $params[1], $params[2]) :

                    $class::$method($params[0], $params[1], $params[2]);

            case 4:

                return ($instance) ?

                    $class->$method($params[0], $params[1], $params[2], $params[3]) :

                    $class::$method($params[0], $params[1], $params[2], $params[3]);

            case 5:

                return ($instance) ?

                    $class->$method($params[0], $params[1], $params[2], $params[3], $params[4]) :

                    $class::$method($params[0], $params[1], $params[2], $params[3], $params[4]);

            default:

                return call_user_func_array($func, $params);

        }

    }

    /**

     * Resets the object to the initial state.

     */

    public function reset() {

        $this->events = array();

        $this->filters = array();

    }

}