nextcloud-server/apps/dav/lib/CalDAV/PublicCalendarObject.php

<?php
/**
 * @copyright Copyright (c) 2017, Georg Ehrke
 *
 * @author Georg Ehrke <oc.list@georgehrke.com>
 * @author Roeland Jago Douma <roeland@famdouma.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\DAV\CalDAV;

class PublicCalendarObject extends CalendarObject {

	/**
	 * public calendars are always shared
	 * @return bool
	 */
	protected function isShared() {
		return true;
	}
}