Throw an exception if file_put_contents fails

* This will help with AppData hardening etc
* Introduced a GenericFileException for if nothing else is appropiate
  - Maybe the other File exceptions should base on this?

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

lib/private/Files/Node/File.php

@@ -26,6 +26,7 @@
 
 namespace OC\Files\Node;
 
+use OCP\Files\GenericFileException;
 use OCP\Files\NotPermittedException;
 
 class File extends Node implements \OCP\Files\File {
@@ -57,11 +58,14 @@ class File extends Node implements \OCP\Files\File {
 	/**
 	 * @param string $data
 	 * @throws \OCP\Files\NotPermittedException
+	 * @throws \OCP\Files\GenericFileException
 	 */
 	public function putContent($data) {
 		if ($this->checkPermissions(\OCP\Constants::PERMISSION_UPDATE)) {
 			$this->sendHooks(array('preWrite'));
-			$this->view->file_put_contents($this->path, $data);
+			if ($this->view->file_put_contents($this->path, $data) === false) {
+				throw new GenericFileException('file_put_contents failed');
+			}
 			$this->fileInfo = null;
 			$this->sendHooks(array('postWrite'));
 		} else {

lib/public/Files/File.php

@@ -53,7 +53,7 @@ interface File extends Node {
 	 *
 	 * @param string $data
 	 * @throws \OCP\Files\NotPermittedException
-	 * @return void
+	 * @throws \OCP\Files\GenericFileException
 	 * @since 6.0.0
 	 */
 	public function putContent($data);

lib/public/Files/GenericFileException.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * @copyright 2018, Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @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 OCP\Files;
+
+/**
+ * Class GenericFileException
+ *
+ * @package OCP\Files
+ * @since 14.0.0
+ */
+class GenericFileException extends \Exception {
+
+}