From 506ee49135ffb2658ccf2e71caa9ed352526a834 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Tim=20D=C3=BCsterhus?= <duesterhus@woltlab.com>
Date: Wed, 17 Feb 2021 11:24:42 +0100
Subject: [PATCH] Add interfaces and traits for reusable events

---
 .../system/event/ICancelableEvent.class.php   | 25 +++++++++++++
 .../files/lib/system/event/IEvent.class.php   | 16 +++++++++
 .../system/event/TCancelableEvent.class.php   | 36 +++++++++++++++++++
 3 files changed, 77 insertions(+)
 create mode 100644 wcfsetup/install/files/lib/system/event/ICancelableEvent.class.php
 create mode 100644 wcfsetup/install/files/lib/system/event/IEvent.class.php
 create mode 100644 wcfsetup/install/files/lib/system/event/TCancelableEvent.class.php

diff --git a/wcfsetup/install/files/lib/system/event/ICancelableEvent.class.php b/wcfsetup/install/files/lib/system/event/ICancelableEvent.class.php
new file mode 100644
index 0000000000..b01acae89c
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/event/ICancelableEvent.class.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace wcf\system\event;
+
+/**
+ * Indicates that the event may be cancelled, stopping the action from happening.
+ *
+ * @author  Tim Duesterhus
+ * @copyright   2001-2021 WoltLab GmbH
+ * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package WoltLabSuite\Core\System\Event
+ * @since   5.5
+ */
+interface ICancelableEvent extends IEvent
+{
+    /**
+     * Cancels the event.
+     */
+    public function cancel(): void;
+
+    /**
+     * Returns whether the event is cancelled.
+     */
+    public function isCancelled(): bool;
+}
diff --git a/wcfsetup/install/files/lib/system/event/IEvent.class.php b/wcfsetup/install/files/lib/system/event/IEvent.class.php
new file mode 100644
index 0000000000..dce3528d7a
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/event/IEvent.class.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace wcf\system\event;
+
+/**
+ * Marker interface for events.
+ *
+ * @author  Tim Duesterhus
+ * @copyright   2001-2021 WoltLab GmbH
+ * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package WoltLabSuite\Core\System\Event
+ * @since   5.5
+ */
+interface IEvent
+{
+}
diff --git a/wcfsetup/install/files/lib/system/event/TCancelableEvent.class.php b/wcfsetup/install/files/lib/system/event/TCancelableEvent.class.php
new file mode 100644
index 0000000000..9497d562c7
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/event/TCancelableEvent.class.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace wcf\system\event;
+
+/**
+ * Default implementation for cancelable events.
+ *
+ * @author  Tim Duesterhus
+ * @copyright   2001-2021 WoltLab GmbH
+ * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package WoltLabSuite\Core\System\Event
+ * @since   5.5
+ */
+trait TCancelableEvent
+{
+    /**
+     * @var bool
+     */
+    private $isCancelled = false;
+
+    /**
+     * @see ICancelableEvent::cancel()
+     */
+    public function cancel(): void
+    {
+        $this->isCancelled = true;
+    }
+
+    /**
+     * @see ICancelableEvent::isCancelled()
+     */
+    public function isCancelled(): bool
+    {
+        return $this->isCancelled;
+    }
+}
-- 
2.20.1