Added DAV client wrapper that support timeout values

Since SabreDAV does not support passing a timeout value to curl, this
commit adds a subclass for it that will set the timeout value to
curlRequest().

lib/private/davclient.php

+<?php
+/**
+ * ownCloud
+ *
+ * @author Vincent Petry
+ * @copyright 2013 Vincent Petry <pvince81@owncloud.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or any later version.
+ *
+ * This library 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 library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * This class extends the SabreDAV client with additional functionality
+ * like request timeout.
+ */
+
+class OC_DAVClient extends \Sabre_DAV_Client{
+
+	protected $requestTimeout;
+
+	/**
+	 * @brief Sets the request timeout or 0 to disable timeout.
+	 * @param int timeout in seconds or 0 to disable
+	 */
+	public function setRequestTimeout($timeout){
+		$this->requestTimeout = (int)$timeout;
+	}
+
+	protected function curlRequest($url, $settings) {
+		if ($this->requestTimeout > 0){
+			$settings[CURLOPT_TIMEOUT] = $this->requestTimeout;
+		}
+		return parent::curlRequest($url, $settings);
+	}
+}