fixed 500 error when accessing non-existing share and add a more comp…

…lete error message when this happens

core/templates/404.php

@@ -14,8 +14,8 @@
 <?php else: ?>
 	<ul>
 		<li class="error">
-			<?php p($l->t('File not found')); ?><br/>
-			<p class="hint"><?php p($l->t('The specified document has not been found on the server.')); ?></p>
+			<?php p($l->t('Resource not found.')); ?><br/>
+			<p class="hint"><?php p($l->t('Share may not longer exist: removed or expired. File or directory may have been deleted.')); ?></p>
 			<p class="hint"><a href="<?php p(OC_Helper::linkTo('', 'index.php')) ?>"><?php p($l->t('You can click here to return to %s.', array($theme->getName()))); ?></a></p>
 		</li>
 	</ul>

lib/public/appframework/http/notfoundresponse.php

@@ -0,0 +1,43 @@
+<?php
+/**
+ * @author Lukas Reschke <lukas@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCP\AppFramework\Http;
+
+use OCP\AppFramework\Http;
+use OCP\Template;
+
+/**
+ * A generic 404 response showing an 404 error page as well to the end-user
+ */
+class NotFoundResponse extends Response {
+
+	public function __construct() {
+		$this->setStatus(404);
+	}
+
+	/**
+	 * @return string
+	 */
+	public function render() {
+		$template = new Template('core', '404', 'guest');
+		return $template->fetchPage();
+	}
+}