No not fail on nonexisting acl users/groups

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/Migration/UnknownUsers.php

@@ -0,0 +1,83 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @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 OCA\Deck\Migration;
+
+use OCA\Deck\Db\Acl;
+use OCA\Deck\Db\AclMapper;
+use OCA\Deck\Db\Board;
+use OCA\Deck\Db\BoardMapper;
+use OCP\IGroupManager;
+use OCP\IUserManager;
+use OCP\Migration\IRepairStep;
+use OCP\Migration\IOutput;
+
+class UnknownUsers implements IRepairStep {
+
+	private $userManager;
+	private $groupManager;
+	private $aclMapper;
+	private $boardMapper;
+
+	public function __construct(IUserManager $userManager, IGroupManager $groupManager, AclMapper $aclMapper, BoardMapper $boardMapper) {
+		$this->userManager = $userManager;
+		$this->groupManager = $groupManager;
+		$this->aclMapper = $aclMapper;
+		$this->boardMapper = $boardMapper;
+	}
+
+	/*
+	 * @inheritdoc
+	 */
+	public function getName() {
+		return 'Delete orphaned ACL rules';
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function run(IOutput $output) {
+		$boards = $this->boardMapper->findAll();
+		/** @var Board $board */
+		foreach ($boards as $board) {
+			$acls = $this->aclMapper->findAll($board->getId());
+			/** @var Acl $acl */
+			foreach ($acls as $acl) {
+				if($acl->getType() === Acl::PERMISSION_TYPE_USER) {
+					$user = $this->userManager->get($acl->getParticipant());
+					if($user === null) {
+						$this->aclMapper->delete($acl);
+					}
+				}
+				if($acl->getType() === Acl::PERMISSION_TYPE_GROUP) {
+					$group = $this->groupManager->get($acl->getParticipant());
+					if($group === null) {
+						$this->aclMapper->delete($acl);
+					}
+				}
+
+			}
+		}
+	}
+}