New BeforeGroupChangedEvent before setDisplayName on groups

lib/private/Group/Group.php

@@ -38,6 +38,7 @@
 use OCP\Group\Backend\IHideFromCollaborationBackend;
 use OCP\Group\Backend\INamedBackend;
 use OCP\Group\Backend\ISetDisplayNameBackend;
+use OCP\Group\Events\BeforeGroupChangedEvent;
 use OCP\Group\Events\GroupChangedEvent;
 use OCP\GroupInterface;
 use OCP\IGroup;
@@ -109,6 +110,7 @@ public function getDisplayName() {
 	public function setDisplayName(string $displayName): bool {
 		$displayName = trim($displayName);
 		if ($displayName !== '') {
+			$this->dispatcher->dispatch(new BeforeGroupChangedEvent($this, 'displayName', $displayName, $this->displayName));
 			foreach ($this->backends as $backend) {
 				if (($backend instanceof ISetDisplayNameBackend)
 					&& $backend->setDisplayName($this->gid, $displayName)) {

lib/public/Group/Events/BeforeGroupChangedEvent.php

@@ -0,0 +1,94 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2023 Julien Veyssier <[email protected]>
+ *
+ * @author Julien Veyssier <[email protected]>
+ *
+ * @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 OCP\Group\Events;
+
+use OCP\EventDispatcher\Event;
+use OCP\IGroup;
+
+/**
+ * @since 26.0.0
+ */
+class BeforeGroupChangedEvent extends Event {
+	private IGroup $group;
+	private string $feature;
+	/** @var mixed */
+	private $value;
+	/** @var mixed */
+	private $oldValue;
+
+	/**
+	 * @since 26.0.0
+	 */
+	public function __construct(IGroup $group,
+		string $feature,
+		$value,
+		$oldValue = null) {
+		parent::__construct();
+		$this->group = $group;
+		$this->feature = $feature;
+		$this->value = $value;
+		$this->oldValue = $oldValue;
+	}
+
+	/**
+	 *
+	 * @since 26.0.0
+	 *
+	 * @return IGroup
+	 */
+	public function getGroup(): IGroup {
+		return $this->group;
+	}
+
+	/**
+	 *
+	 * @since 26.0.0
+	 *
+	 * @return string
+	 */
+	public function getFeature(): string {
+		return $this->feature;
+	}
+
+	/**
+	 * @since 26.0.0
+	 *
+	 * @return mixed
+	 */
+	public function getValue() {
+		return $this->value;
+	}
+
+	/**
+	 *
+	 * @since 26.0.0
+	 *
+	 * @return mixed
+	 */
+	public function getOldValue() {
+		return $this->oldValue;
+	}
+}