Add background job placeholder for nc14

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/AppInfo/Application.php

@@ -89,6 +89,16 @@ class Application extends App {
 				return new ExpireGroupVersionsPlaceholder();
 			}
 		});
+
+		$container->registerService(\OCA\GroupFolders\BackgroundJob\ExpireGroupVersions::class, function(IAppContainer $c) {
+			if (interface_exists('OCA\Files_Versions\Versions\IVersionBackend')) {
+				return new \OCA\GroupFolders\BackgroundJob\ExpireGroupVersions(
+					$c->query(GroupVersionsExpireManager::class)
+				);
+			} else {
+				return new \OCA\GroupFolders\BackgroundJob\ExpireGroupVersionsPlaceholder();
+			}
+		});
 	}
 
 	public function register() {

lib/BackgroundJob/ExpireGroupVersionsPlaceholder.php

@@ -0,0 +1,34 @@
+<?php declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2018 Robin Appelman <robin@icewind.nl>
+ *
+ * @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\GroupFolders\BackgroundJob;
+
+class ExpireGroupVersionsPlaceholder extends \OC\BackgroundJob\TimedJob {
+
+	public function __construct() {
+		// Run once per hour
+		$this->setInterval(60 * 60);
+	}
+
+	protected function run($argument) {
+		// noop
+	}
+}