Add ActionDispatcher to new Http lib

The ActionDispatcher is responsible for dispatching the CakePHP request
and response. It replicates the behavior that Dispatcher provides in
a more decoupled way. This class also handles ensuring that Dispatch
filter events are triggered at the appropriate point in time.

src/Http/ActionDispatcher.php

@@ -0,0 +1,152 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link          http://cakephp.org CakePHP(tm) Project
+ * @since         3.3.0
+ * @license       http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Http;
+
+use Cake\Controller\Controller;
+use Cake\Event\EventDispatcherTrait;
+use Cake\Event\EventListenerInterface;
+use Cake\Http\ControllerFactory;
+use Cake\Network\Request;
+use Cake\Network\Response;
+use Cake\Routing\DispatcherFactory;
+use Cake\Routing\Exception\MissingControllerException;
+use Cake\Routing\Router;
+use LogicException;
+
+/**
+ * This class provides compatibility with dispatcher filters
+ * and interacting with the controller layers.
+ *
+ * Long term this should just be the controller dispatcher, but
+ * for now it will do a bit more than that.
+ */
+class ActionDispatcher
+{
+    use EventDispatcherTrait;
+
+    /**
+     * Attached routing filters
+     *
+     * @var array
+     */
+    protected $filters = [];
+
+    /**
+     * Controller factory instance.
+     *
+     * @var \Cake\Http\ControllerFactory
+     */
+    protected $factory;
+
+    /**
+     * Constructor
+     *
+     * @param \Cake\Http\ControllerFactory $factory A controller factory instance.
+     */
+    public function __construct($factory = null)
+    {
+        // Compatibility with DispatcherFilters.
+        foreach (DispatcherFactory::filters() as $filter) {
+            $this->addFilter($filter);
+        }
+        $this->factory = $factory ?: new ControllerFactory();
+    }
+
+    /**
+     * Dispatches a Request & Response
+     *
+     * @param \Cake\Network\Request $request The request to dispatch.
+     * @param \Cake\Network\Response $response The response to dispatch.
+     * @return \Cake\Network\Response a modified/replaced response.
+     */
+    public function dispatch(Request $request, Response $response)
+    {
+        Router::pushRequest($request);
+        $beforeEvent = $this->dispatchEvent('Dispatcher.beforeDispatch', compact('request', 'response'));
+
+        $request = $beforeEvent->data['request'];
+        if ($beforeEvent->result instanceof Response) {
+            return $beforeEvent->result;
+        }
+        $controller = $this->factory->create($request, $response);
+        $response = $this->_invoke($controller);
+        if (isset($request->params['return'])) {
+            return $response;
+        }
+
+        $afterEvent = $this->dispatchEvent('Dispatcher.afterDispatch', compact('request', 'response'));
+        return $afterEvent->data['response'];
+    }
+
+    /**
+     * Invoke a controller's action and wrapping methods.
+     *
+     * @param \Cake\Controller\Controller $controller The controller to invoke.
+     * @return \Cake\Network\Response The response
+     * @throw \LogicException If the controller action returns a non-response value.
+     */
+    protected function _invoke(Controller $controller)
+    {
+        $result = $controller->startupProcess();
+        if ($result instanceof Response) {
+            return $result;
+        }
+
+        $response = $controller->invokeAction();
+        if ($response !== null && !($response instanceof Response)) {
+            throw new LogicException('Controller actions can only Cake\Network\Response instances');
+        }
+
+        if (!$response && $controller->autoRender) {
+            $response = $controller->render();
+        } elseif (!$response) {
+            $response = $controller->response;
+        }
+
+        $result = $controller->shutdownProcess();
+        if ($result instanceof Response) {
+            return $result;
+        }
+
+        return $response;
+    }
+
+    /**
+     * Add a filter to this dispatcher.
+     *
+     * The added filter will be attached to the event manager used
+     * by this dispatcher.
+     *
+     * @param \Cake\Event\EventListenerInterface $filter The filter to connect. Can be
+     *   any EventListenerInterface. Typically an instance of \Cake\Routing\DispatcherFilter.
+     * @return void
+     * @deprecated This is only available for backwards compatibility with DispatchFilters
+     */
+    public function addFilter(EventListenerInterface $filter)
+    {
+        $this->filters[] = $filter;
+        $this->eventManager()->on($filter);
+    }
+
+    /**
+     * Get the connected filters.
+     *
+     * @return array
+     */
+    public function getFilters()
+    {
+        return $this->filters;
+    }
+}