Add event dispatcher to OCP

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

3 files changed, 303 insertions, 0 deletions

diff --git a/lib/private/EventDispatcher/EventDispatcher.php b/lib/private/EventDispatcher/EventDispatcher.php
new file mode 100644
index 00000000000..8db2f3101be
--- /dev/null
+++ b/lib/private/EventDispatcher/EventDispatcher.php
@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\EventDispatcher;
+
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\IContainer;
+use OCP\ILogger;
+use OCP\IServerContainer;
+use Symfony\Component\EventDispatcher\EventDispatcher as SymfonyDispatcher;
+
+class EventDispatcher implements IEventDispatcher {
+
+	/** @var SymfonyDispatcher */
+	private $dispatcher;
+
+	/** @var IContainer */
+	private $container;
+
+	/** @var ILogger */
+	private $logger;
+
+	public function __construct(SymfonyDispatcher $dispatcher,
+								IServerContainer $container,
+								ILogger $logger) {
+		$this->dispatcher = $dispatcher;
+		$this->container = $container;
+		$this->logger = $logger;
+	}
+
+	public function addListener(string $eventName,
+								callable $listener,
+								int $priority = 0): void {
+		$this->dispatcher->addListener($eventName, $listener, $priority);
+	}
+
+	public function addServiceListener(string $eventName,
+									   string $className,
+									   int $priority = 0): void {
+		$listener = new ServiceEventListener(
+			$this->container,
+			$className,
+			$this->logger
+		);
+
+		$this->addListener($eventName, $listener, $priority);
+	}
+
+	public function dispatch(string $eventName,
+							 Event $event): void {
+
+		$this->dispatcher->dispatch($eventName, $event);
+	}
+
+	/**
+	 * @return SymfonyDispatcher
+	 */
+	public function getSymfonyDispatcher(): SymfonyDispatcher {
+		return $this->dispatcher;
+	}
+
+}
diff --git a/lib/private/EventDispatcher/ServiceEventListener.php b/lib/private/EventDispatcher/ServiceEventListener.php
new file mode 100644
index 00000000000..f5b6cd9b79d
--- /dev/null
+++ b/lib/private/EventDispatcher/ServiceEventListener.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\EventDispatcher;
+
+use OCP\AppFramework\QueryException;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use OCP\IContainer;
+use OCP\ILogger;
+
+/**
+ * Lazy service event listener
+ *
+ * Makes it possible to lazy-route a dispatched event to a service instance
+ * created by the service container
+ */
+final class ServiceEventListener {
+
+	/** @var IContainer */
+	private $container;
+
+	/** @var string */
+	private $class;
+
+	/** @var ILogger */
+	private $logger;
+
+	/** @var null|IEventListener */
+	private $service;
+
+	public function __construct(IContainer $container,
+								string $class,
+								ILogger $logger) {
+		$this->container = $container;
+		$this->class = $class;
+		$this->logger = $logger;
+	}
+
+	public function __invoke(Event $event) {
+		if ($this->service === null) {
+			try {
+				$this->service = $this->container->query($this->class);
+			} catch (QueryException $e) {
+				$this->logger->logException($e, [
+					'level' => ILogger::ERROR,
+					'message' => "Could not load event listener service " . $this->class,
+				]);
+				return;
+			}
+		}
+
+		$this->service->handle($event);
+	}
+
+}
diff --git a/lib/private/EventDispatcher/SymfonyAdapter.php b/lib/private/EventDispatcher/SymfonyAdapter.php
new file mode 100644
index 00000000000..f2f2fbf59fd
--- /dev/null
+++ b/lib/private/EventDispatcher/SymfonyAdapter.php
@@ -0,0 +1,140 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\EventDispatcher;
+
+use function is_callable;
+use OCP\EventDispatcher\Event;
+use Symfony\Component\EventDispatcher\Event as SymfonyEvent;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+class SymfonyAdapter implements EventDispatcherInterface {
+
+	/** @var EventDispatcher */
+	private $eventDispatcher;
+
+	public function __construct(EventDispatcher $eventDispatcher) {
+		$this->eventDispatcher = $eventDispatcher;
+	}
+
+	/**
+	 * Dispatches an event to all registered listeners.
+	 *
+	 * @param string $eventName The name of the event to dispatch. The name of
+	 *                              the event is the name of the method that is
+	 *                              invoked on listeners.
+	 * @param SymfonyEvent|null $event The event to pass to the event handlers/listeners
+	 *                              If not supplied, an empty Event instance is created
+	 *
+	 * @return SymfonyEvent
+	 */
+	public function dispatch($eventName, SymfonyEvent $event = null) {
+		if ($event instanceof Event) {
+			$this->eventDispatcher->dispatch($eventName, $event);
+		} else {
+			// Legacy event
+			$this->eventDispatcher->getSymfonyDispatcher()->dispatch($eventName, $event);
+		}
+	}
+
+	/**
+	 * Adds an event listener that listens on the specified events.
+	 *
+	 * @param string $eventName The event to listen on
+	 * @param callable $listener The listener
+	 * @param int $priority The higher this value, the earlier an event
+	 *                            listener will be triggered in the chain (defaults to 0)
+	 */
+	public function addListener($eventName, $listener, $priority = 0) {
+		if (is_callable($listener)) {
+			$this->eventDispatcher->addListener($eventName, $listener, $priority);
+		} else {
+			// Legacy listener
+			$this->eventDispatcher->getSymfonyDispatcher()->addListener($eventName, $listener, $priority);
+		}
+	}
+
+	/**
+	 * Adds an event subscriber.
+	 *
+	 * The subscriber is asked for all the events it is
+	 * interested in and added as a listener for these events.
+	 */
+	public function addSubscriber(EventSubscriberInterface $subscriber) {
+		$this->eventDispatcher->getSymfonyDispatcher()->addSubscriber($subscriber);
+	}
+
+	/**
+	 * Removes an event listener from the specified events.
+	 *
+	 * @param string $eventName The event to remove a listener from
+	 * @param callable $listener The listener to remove
+	 */
+	public function removeListener($eventName, $listener) {
+		$this->eventDispatcher->getSymfonyDispatcher()->removeListener($eventName, $listener);
+	}
+
+	public function removeSubscriber(EventSubscriberInterface $subscriber) {
+		$this->eventDispatcher->getSymfonyDispatcher()->removeSubscriber($subscriber);
+	}
+
+	/**
+	 * Gets the listeners of a specific event or all listeners sorted by descending priority.
+	 *
+	 * @param string|null $eventName The name of the event
+	 *
+	 * @return array The event listeners for the specified event, or all event listeners by event name
+	 */
+	public function getListeners($eventName = null) {
+		return $this->eventDispatcher->getSymfonyDispatcher()->getListeners($eventName);
+	}
+
+	/**
+	 * Gets the listener priority for a specific event.
+	 *
+	 * Returns null if the event or the listener does not exist.
+	 *
+	 * @param string $eventName The name of the event
+	 * @param callable $listener The listener
+	 *
+	 * @return int|null The event listener priority
+	 */
+	public function getListenerPriority($eventName, $listener) {
+		return $this->eventDispatcher->getSymfonyDispatcher()->getListenerPriority($eventName, $listener);
+	}
+
+	/**
+	 * Checks whether an event has any registered listeners.
+	 *
+	 * @param string|null $eventName The name of the event
+	 *
+	 * @return bool true if the specified event has any listeners, false otherwise
+	 */
+	public function hasListeners($eventName = null) {
+		return $this->eventDispatcher->getSymfonyDispatcher()->hasListeners($eventName);
+	}
+
+}