Introduce BackendService for managing external storage backends

Backends are registered to the BackendService through new data
structures:

Backends are concrete classes, deriving from
\OCA\Files_External\Lib\Backend\Backend. During construction, the
various configuration parameters of the Backend can be set, in a design
similar to Symfony Console.

DefinitionParameter stores a parameter configuration for an external
storage: name of parameter, human-readable name, type of parameter
(text, password, hidden, checkbox), flags (optional or not).

Storages in the StoragesController now get their parameters validated
server-side (fixes a TODO).

12 files changed, 958 insertions, 211 deletions

diff --git a/apps/files_external/lib/backend/backend.php b/apps/files_external/lib/backend/backend.php
new file mode 100644
index 00000000000..e7cd27a1d6c
--- /dev/null
+++ b/apps/files_external/lib/backend/backend.php
@@ -0,0 +1,94 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@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 OCA\Files_External\Lib\Backend;
+
+use \OCA\Files_External\Lib\StorageConfig;
+use \OCA\Files_External\Lib\VisibilityTrait;
+use \OCA\Files_External\Lib\FrontendDefinitionTrait;
+use \OCA\Files_External\Lib\PriorityTrait;
+use \OCA\Files_External\Lib\DependencyTrait;
+use \OCA\Files_External\Lib\StorageModifierTrait;
+
+/**
+ * Storage backend
+ */
+class Backend implements \JsonSerializable {
+
+	use VisibilityTrait;
+	use FrontendDefinitionTrait;
+	use PriorityTrait;
+	use DependencyTrait;
+	use StorageModifierTrait;
+
+	/** @var string storage class */
+	private $storageClass;
+
+	/**
+	 * @return string
+	 */
+	public function getClass() {
+		// return storage class for legacy compat
+		return $this->getStorageClass();
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getStorageClass() {
+		return $this->storageClass;
+	}
+
+	/**
+	 * @param string $class
+	 * @return self
+	 */
+	public function setStorageClass($class) {
+		$this->storageClass = $class;
+		return $this;
+	}
+
+	/**
+	 * Serialize into JSON for client-side JS
+	 *
+	 * @return array
+	 */
+	public function jsonSerialize() {
+		$data = $this->jsonSerializeDefinition();
+
+		$data['backend'] = $data['name']; // legacy compat
+		$data['priority'] = $this->getPriority();
+
+		return $data;
+	}
+
+	/**
+	 * Check if parameters are satisfied in a StorageConfig
+	 *
+	 * @param StorageConfig $storage
+	 * @return bool
+	 */
+	public function validateStorage(StorageConfig $storage) {
+		return $this->validateStorageDefinition($storage);
+	}
+
+}
+
diff --git a/apps/files_external/lib/config.php b/apps/files_external/lib/config.php
index 8fcf39cc767..11dec94621a 100644
--- a/apps/files_external/lib/config.php
+++ b/apps/files_external/lib/config.php
@@ -32,6 +32,9 @@
  */
 
 use phpseclib\Crypt\AES;
+use \OCP\AppFramework\IAppContainer;
+use \OCA\Files_External\Lib\BackendConfig;
+use \OCA\Files_External\Service\BackendService;
 
 /**
  * Class to configure mount.json globally and for users
@@ -51,71 +54,19 @@ class OC_Mount_Config {
 	// whether to skip backend test (for unit tests, as this static class is not mockable)
 	public static $skipTest = false;
 
-	private static $backends = array();
+	/** @var IAppContainer */
+	private static $appContainer;
 
 	/**
-	 * @param string $class
-	 * @param array $definition
-	 * @return bool
-	 */
-	public static function registerBackend($class, $definition) {
-		if (!isset($definition['backend'])) {
-			return false;
-		}
-
-		OC_Mount_Config::$backends[$class] = $definition;
-		return true;
-	}
-
-	/**
-	 * Setup backends
+	 * Teach OC_Mount_Config about the AppFramework
 	 *
-	 * @return array of previously registered backends
+	 * @param IAppContainer $appContainer
 	 */
-	public static function setUp($backends = array()) {
-		$backup = self::$backends;
-		self::$backends = $backends;
-
-		return $backup;
-	}
-
-	/**
-	 * Get details on each of the external storage backends, used for the mount config UI
-	 * If a custom UI is needed, add the key 'custom' and a javascript file with that name will be loaded
-	 * If the configuration parameter should be secret, add a '*' to the beginning of the value
-	 * If the configuration parameter is a boolean, add a '!' to the beginning of the value
-	 * If the configuration parameter is optional, add a '&' to the beginning of the value
-	 * If the configuration parameter is hidden, add a '#' to the beginning of the value
-	 *
-	 * @return array
-	 */
-	public static function getBackends() {
-		$sortFunc = function ($a, $b) {
-			return strcasecmp($a['backend'], $b['backend']);
-		};
-
-		$backEnds = array();
-
-		foreach (OC_Mount_Config::$backends as $class => $backend) {
-			if (isset($backend['has_dependencies']) and $backend['has_dependencies'] === true) {
-				if (!method_exists($class, 'checkDependencies')) {
-					\OCP\Util::writeLog('files_external',
-						"Backend class $class has dependencies but doesn't provide method checkDependencies()",
-						\OCP\Util::DEBUG);
-					continue;
-				} elseif ($class::checkDependencies() !== true) {
-					continue;
-				}
-			}
-			$backEnds[$class] = $backend;
-		}
-
-		uasort($backEnds, $sortFunc);
-
-		return $backEnds;
+	public static function initApp(IAppContainer $appContainer) {
+		self::$appContainer = $appContainer;
 	}
 
-	/**
+	/*
 	 * Hook that mounts the given user's visible mount points
 	 *
 	 * @param array $data
@@ -151,14 +102,14 @@ class OC_Mount_Config {
 	/**
 	 * Returns the mount points for the given user.
 	 * The mount point is relative to the data directory.
+	 * TODO: Move me into StoragesService
 	 *
 	 * @param string $user user
 	 * @return array of mount point string as key, mountpoint config as value
 	 */
 	public static function getAbsoluteMountPoints($user) {
 		$mountPoints = array();
-
-		$backends = self::getBackends();
+		$backendService = self::$appContainer->query('OCA\Files_External\Service\BackendService');
 
 		// Load system mount points
 		$mountConfig = self::readData();
@@ -166,18 +117,20 @@ class OC_Mount_Config {
 		// Global mount points (is this redundant?)
 		if (isset($mountConfig[self::MOUNT_TYPE_GLOBAL])) {
 			foreach ($mountConfig[self::MOUNT_TYPE_GLOBAL] as $mountPoint => $options) {
+				$backend = $backendService->getBackend($options['class']);
 				$options['personal'] = false;
 				$options['options'] = self::decryptPasswords($options['options']);
 				if (!isset($options['priority'])) {
-					$options['priority'] = $backends[$options['class']]['priority'];
+					$options['priority'] = $backend->getPriority();
 				}
 
+
 				// Override if priority greater
 				if ((!isset($mountPoints[$mountPoint]))
 					|| ($options['priority'] >= $mountPoints[$mountPoint]['priority'])
 				) {
 					$options['priority_type'] = self::MOUNT_TYPE_GLOBAL;
-					$options['backend'] = $backends[$options['class']]['backend'];
+					$options['backend'] = $backend->getText();
 					$mountPoints[$mountPoint] = $options;
 				}
 			}
@@ -190,10 +143,11 @@ class OC_Mount_Config {
 				foreach ($options as &$option) {
 					$option = self::setUserVars($user, $option);
 				}
+				$backend = $backendService->getBackend($options['class']);
 				$options['personal'] = false;
 				$options['options'] = self::decryptPasswords($options['options']);
 				if (!isset($options['priority'])) {
-					$options['priority'] = $backends[$options['class']]['priority'];
+					$options['priority'] = $backend->getPriority();
 				}
 
 				// Override if priority greater
@@ -201,7 +155,7 @@ class OC_Mount_Config {
 					|| ($options['priority'] >= $mountPoints[$mountPoint]['priority'])
 				) {
 					$options['priority_type'] = self::MOUNT_TYPE_GLOBAL;
-					$options['backend'] = $backends[$options['class']]['backend'];
+					$options['backend'] = $backend->getText();
 					$mountPoints[$mountPoint] = $options;
 				}
 			}
@@ -215,10 +169,11 @@ class OC_Mount_Config {
 						foreach ($options as &$option) {
 							$option = self::setUserVars($user, $option);
 						}
+						$backend = $backendService->getBackend($options['class']);
 						$options['personal'] = false;
 						$options['options'] = self::decryptPasswords($options['options']);
 						if (!isset($options['priority'])) {
-							$options['priority'] = $backends[$options['class']]['priority'];
+							$options['priority'] = $backend->getPriority();
 						}
 
 						// Override if priority greater or if priority type different
@@ -227,7 +182,7 @@ class OC_Mount_Config {
 							|| ($mountPoints[$mountPoint]['priority_type'] !== self::MOUNT_TYPE_GROUP)
 						) {
 							$options['priority_type'] = self::MOUNT_TYPE_GROUP;
-							$options['backend'] = $backends[$options['class']]['backend'];
+							$options['backend'] = $backend->getText();
 							$mountPoints[$mountPoint] = $options;
 						}
 					}
@@ -243,10 +198,11 @@ class OC_Mount_Config {
 						foreach ($options as &$option) {
 							$option = self::setUserVars($user, $option);
 						}
+						$backend = $backendService->getBackend($options['class']);
 						$options['personal'] = false;
 						$options['options'] = self::decryptPasswords($options['options']);
 						if (!isset($options['priority'])) {
-							$options['priority'] = $backends[$options['class']]['priority'];
+							$options['priority'] = $backend->getPriority();
 						}
 
 						// Override if priority greater or if priority type different
@@ -255,7 +211,7 @@ class OC_Mount_Config {
 							|| ($mountPoints[$mountPoint]['priority_type'] !== self::MOUNT_TYPE_USER)
 						) {
 							$options['priority_type'] = self::MOUNT_TYPE_USER;
-							$options['backend'] = $backends[$options['class']]['backend'];
+							$options['backend'] = $backend->getText();
 							$mountPoints[$mountPoint] = $options;
 						}
 					}
@@ -263,19 +219,18 @@ class OC_Mount_Config {
 			}
 		}
 
-		$personalBackends = self::getPersonalBackends();
-
 		// Load personal mount points
 		$mountConfig = self::readData($user);
 		if (isset($mountConfig[self::MOUNT_TYPE_USER][$user])) {
 			foreach ($mountConfig[self::MOUNT_TYPE_USER][$user] as $mountPoint => $options) {
-				if (isset($personalBackends[$options['class']])) {
+				$backend = $backendService->getBackend($options['class']);
+				if ($backend->isVisibleFor(BackendService::VISIBILITY_PERSONAL)) {
 					$options['personal'] = true;
 					$options['options'] = self::decryptPasswords($options['options']);
 
 					// Always override previous config
 					$options['priority_type'] = self::MOUNT_TYPE_PERSONAL;
-					$options['backend'] = $backends[$options['class']]['backend'];
+					$options['backend'] = $backend->getText();
 					$mountPoints[$mountPoint] = $options;
 				}
 			}
@@ -304,43 +259,6 @@ class OC_Mount_Config {
 		return $input;
 	}
 
-
-	/**
-	 * Get details on each of the external storage backends, used for the mount config UI
-	 * Some backends are not available as a personal backend, f.e. Local and such that have
-	 * been disabled by the admin.
-	 *
-	 * If a custom UI is needed, add the key 'custom' and a javascript file with that name will be loaded
-	 * If the configuration parameter should be secret, add a '*' to the beginning of the value
-	 * If the configuration parameter is a boolean, add a '!' to the beginning of the value
-	 * If the configuration parameter is optional, add a '&' to the beginning of the value
-	 * If the configuration parameter is hidden, add a '#' to the beginning of the value
-	 *
-	 * @return array
-	 */
-	public static function getPersonalBackends() {
-
-		// Check whether the user has permissions to add personal storage backends
-		// return an empty array if this is not the case
-		if (OCP\Config::getAppValue('files_external', 'allow_user_mounting', 'yes') !== 'yes') {
-			return array();
-		}
-
-		$backEnds = self::getBackends();
-
-		// Remove local storage and other disabled storages
-		unset($backEnds['\OC\Files\Storage\Local']);
-
-		$allowedBackEnds = explode(',', OCP\Config::getAppValue('files_external', 'user_mounting_backends', ''));
-		foreach ($backEnds as $backend => $null) {
-			if (!in_array($backend, $allowedBackEnds)) {
-				unset($backEnds[$backend]);
-			}
-		}
-
-		return $backEnds;
-	}
-
 	/**
 	 * Get the system mount points
 	 * The returned array is not in the same format as getUserMountPoints()
@@ -349,7 +267,7 @@ class OC_Mount_Config {
 	 */
 	public static function getSystemMountPoints() {
 		$mountPoints = self::readData();
-		$backends = self::getBackends();
+		$backendService = self::$appContainer->query('\OCA\Files_External\Service\BackendService');
 		$system = array();
 		if (isset($mountPoints[self::MOUNT_TYPE_GROUP])) {
 			foreach ($mountPoints[self::MOUNT_TYPE_GROUP] as $group => $mounts) {
@@ -358,9 +276,10 @@ class OC_Mount_Config {
 					if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
 						$mount['class'] = '\OC\Files\Storage\\' . substr($mount['class'], 15);
 					}
+					$backend = $backendService->getBackend($mount['class']);
 					$mount['options'] = self::decryptPasswords($mount['options']);
 					if (!isset($mount['priority'])) {
-						$mount['priority'] = $backends[$mount['class']]['priority'];
+						$mount['priority'] = $backend->getPriority();
 					}
 					// Remove '/$user/files/' from mount point
 					$mountPoint = substr($mountPoint, 13);
@@ -368,7 +287,7 @@ class OC_Mount_Config {
 					$config = array(
 						'class' => $mount['class'],
 						'mountpoint' => $mountPoint,
-						'backend' => $backends[$mount['class']]['backend'],
+						'backend' => $backend->getText(),
 						'priority' => $mount['priority'],
 						'options' => $mount['options'],
 						'applicable' => array('groups' => array($group), 'users' => array())
@@ -401,16 +320,17 @@ class OC_Mount_Config {
 					if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
 						$mount['class'] = '\OC\Files\Storage\\' . substr($mount['class'], 15);
 					}
+					$backend = $backendService->getBackend($mount['class']);
 					$mount['options'] = self::decryptPasswords($mount['options']);
 					if (!isset($mount['priority'])) {
-						$mount['priority'] = $backends[$mount['class']]['priority'];
+						$mount['priority'] = $backend->getPriority();
 					}
 					// Remove '/$user/files/' from mount point
 					$mountPoint = substr($mountPoint, 13);
 					$config = array(
 						'class' => $mount['class'],
 						'mountpoint' => $mountPoint,
-						'backend' => $backends[$mount['class']]['backend'],
+						'backend' => $backend->getText(),
 						'priority' => $mount['priority'],
 						'options' => $mount['options'],
 						'applicable' => array('groups' => array(), 'users' => array($user))
@@ -447,7 +367,7 @@ class OC_Mount_Config {
 	 */
 	public static function getPersonalMountPoints() {
 		$mountPoints = self::readData(OCP\User::getUser());
-		$backEnds = self::getBackends();
+		$backendService = self::$appContainer->query('\OCA\Files_External\Service\BackendService');
 		$uid = OCP\User::getUser();
 		$personal = array();
 		if (isset($mountPoints[self::MOUNT_TYPE_USER][$uid])) {
@@ -456,12 +376,13 @@ class OC_Mount_Config {
 				if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
 					$mount['class'] = '\OC\Files\Storage\\' . substr($mount['class'], 15);
 				}
+				$backend = $backendService->getBackend($mount['class']);
 				$mount['options'] = self::decryptPasswords($mount['options']);
 				$config = array(
 					'class' => $mount['class'],
 					// Remove '/uid/files/' from mount point
 					'mountpoint' => substr($mountPoint, strlen($uid) + 8),
-					'backend' => $backEnds[$mount['class']]['backend'],
+					'backend' => $backend->getText(),
 					'options' => $mount['options']
 				);
 				if (isset($mount['id'])) {
@@ -535,7 +456,7 @@ class OC_Mount_Config {
 										 $applicable,
 										 $isPersonal = false,
 										 $priority = null) {
-		$backends = self::getBackends();
+		$backendService = self::$appContainer->query('\OCA\Files_External\Service\BackendService');
 		$mountPoint = OC\Files\Filesystem::normalizePath($mountPoint);
 		$relMountPoint = $mountPoint;
 		if ($mountPoint === '' || $mountPoint === '/') {
@@ -543,15 +464,15 @@ class OC_Mount_Config {
 			return false;
 		}
 
-		if (!isset($backends[$class])) {
+		$backend = $backendService->getBackend($class);
+		if (!isset($backend)) {
 			// invalid backend
 			return false;
 		}
 		if ($isPersonal) {
 			// Verify that the mount point applies for the current user
 			// Prevent non-admin users from mounting local storage and other disabled backends
-			$allowed_backends = self::getPersonalBackends();
-			if ($applicable != OCP\User::getUser() || !isset($allowed_backends[$class])) {
+			if ($applicable != OCP\User::getUser() || !$backend->isVisibleFor(BackendConfig::VISIBILITY_PERSONAL)) {
 				return false;
 			}
 			$mountPoint = '/' . $applicable . '/files/' . ltrim($mountPoint, '/');
@@ -578,13 +499,8 @@ class OC_Mount_Config {
 
 		// Set default priority if none set
 		if (!isset($mountPoints[$mountType][$applicable][$mountPoint]['priority'])) {
-			if (isset($backends[$class]['priority'])) {
-				$mountPoints[$mountType][$applicable][$mountPoint]['priority']
-					= $backends[$class]['priority'];
-			} else {
-				$mountPoints[$mountType][$applicable][$mountPoint]['priority']
-					= 100;
-			}
+			$mountPoints[$mountType][$applicable][$mountPoint]['priority']
+				= $backend->getPriority();
 		}
 
 		self::writeData($isPersonal ? OCP\User::getUser() : null, $mountPoints);
@@ -721,74 +637,35 @@ class OC_Mount_Config {
 	}
 
 	/**
-	 * check dependencies
+	 * Get backend dependency message
+	 * TODO: move into AppFramework along with templates
+	 *
+	 * @param BackendConfig[] $backends
+	 * @return string
 	 */
-	public static function checkDependencies() {
-		$dependencies = array();
-		foreach (OC_Mount_Config::$backends as $class => $backend) {
-			if (isset($backend['has_dependencies']) and $backend['has_dependencies'] === true) {
-				$result = $class::checkDependencies();
-				if ($result !== true) {
-					if (!is_array($result)) {
-						$result = array($result);
-					}
-					foreach ($result as $key => $value) {
-						if (is_numeric($key)) {
-							OC_Mount_Config::addDependency($dependencies, $value, $backend['backend']);
-						} else {
-							OC_Mount_Config::addDependency($dependencies, $key, $backend['backend'], $value);
-						}
-					}
-				}
-			}
-		}
-
-		if (count($dependencies) > 0) {
-			return OC_Mount_Config::generateDependencyMessage($dependencies);
-		}
-		return '';
-	}
-
-	private static function addDependency(&$dependencies, $module, $backend, $message = null) {
-		if (!isset($dependencies[$module])) {
-			$dependencies[$module] = array();
-		}
-
-		if ($message === null) {
-			$dependencies[$module][] = $backend;
-		} else {
-			$dependencies[$module][] = array('backend' => $backend, 'message' => $message);
-		}
-	}
-
-	private static function generateDependencyMessage($dependencies) {
+	public static function dependencyMessage($backends) {
 		$l = new \OC_L10N('files_external');
-		$dependencyMessage = '';
-		foreach ($dependencies as $module => $backends) {
-			$dependencyGroup = array();
-			foreach ($backends as $backend) {
-				if (is_array($backend)) {
-					$dependencyMessage .= '<br />' . $l->t('<b>Note:</b> ') . $backend['message'];
+		$message = '';
+		$dependencyGroups = [];
+
+		foreach ($backends as $backend) {
+			foreach ($backend->checkDependencies() as $dependency) {
+				if ($message = $dependency->getMessage()) {
+					$message .= '<br />' . $l->t('<b>Note:</b> ') . $message;
 				} else {
-					$dependencyGroup[] = $backend;
+					$dependencyGroups[$dependency->getDependency()][] = $backend;
 				}
 			}
+		}
 
-			$dependencyGroupCount = count($dependencyGroup);
-			if ($dependencyGroupCount > 0) {
-				$backends = '';
-				for ($i = 0; $i < $dependencyGroupCount; $i++) {
-					if ($i > 0 && $i === $dependencyGroupCount - 1) {
-						$backends .= ' ' . $l->t('and') . ' ';
-					} elseif ($i > 0) {
-						$backends .= ', ';
-					}
-					$backends .= '<i>' . $dependencyGroup[$i] . '</i>';
-				}
-				$dependencyMessage .= '<br />' . OC_Mount_Config::getSingleDependencyMessage($l, $module, $backends);
-			}
+		foreach ($dependencyGroups as $module => $dependants) {
+			$backends = implode(', ', array_map(function($backend) {
+				return '<i>' . $backend->getText() . '</i>';
+			}, $dependants));
+			$message .= '<br />' . OC_Mount_Config::getSingleDependencyMessage($l, $module, $backends);
 		}
-		return $dependencyMessage;
+
+		return $message;
 	}
 
 	/**
diff --git a/apps/files_external/lib/config/configadapter.php b/apps/files_external/lib/config/configadapter.php
index b5c2ba4fc92..6956de1e748 100644
--- a/apps/files_external/lib/config/configadapter.php
+++ b/apps/files_external/lib/config/configadapter.php
@@ -24,14 +24,23 @@ namespace OCA\Files_External\Config;
 
 use OC\Files\Mount\MountPoint;
 use OCP\Files\Storage\IStorageFactory;
-use OCA\Files_External\PersonalMount;
+use OCA\Files_External\Lib\PersonalMount;
 use OCP\Files\Config\IMountProvider;
 use OCP\IUser;
+use OCA\Files_external\Service\UserStoragesService;
 
 /**
  * Make the old files_external config work with the new public mount config api
  */
 class ConfigAdapter implements IMountProvider {
+
+	/**
+	 * @param UserStoragesService $userStoragesService
+	 */
+	public function __construct(UserStoragesService $userStoragesService) {
+		$this->userStoragesService = $userStoragesService;
+	}
+
 	/**
 	 * Get all mountpoints applicable for the user
 	 *
@@ -49,7 +58,8 @@ class ConfigAdapter implements IMountProvider {
 			}
 			$mountOptions = isset($options['mountOptions']) ? $options['mountOptions'] : [];
 			if (isset($options['personal']) && $options['personal']) {
-				$mounts[] = new PersonalMount($options['class'], $mountPoint, $options['options'], $loader, $mountOptions);
+				$mount = new PersonalMount($this->userStoragesService, $options['id'], $options['class'], $mountPoint, $options['options'], $loader, $mountOptions);
+				$mounts[] = $mount;
 			} else {
 				$mounts[] = new MountPoint($options['class'], $mountPoint, $options['options'], $loader, $mountOptions);
 			}
diff --git a/apps/files_external/lib/definitionparameter.php b/apps/files_external/lib/definitionparameter.php
new file mode 100644
index 00000000000..4b560908b69
--- /dev/null
+++ b/apps/files_external/lib/definitionparameter.php
@@ -0,0 +1,179 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@karoshi.org.uk>
+ *
+ * @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 OCA\Files_External\Lib;
+
+/**
+ * Parameter for an external storage definition
+ */
+class DefinitionParameter implements \JsonSerializable {
+
+	/** Value constants */
+	const VALUE_TEXT = 0;
+	const VALUE_BOOLEAN = 1;
+	const VALUE_PASSWORD = 2;
+	const VALUE_HIDDEN = 3;
+
+	/** Flag constants */
+	const FLAG_NONE = 0;
+	const FLAG_OPTIONAL = 1;
+
+	/** @var string name of parameter */
+	private $name;
+
+	/** @var string human-readable parameter text */
+	private $text;
+
+	/** @var int value type, see self::VALUE_* constants */
+	private $type = self::VALUE_TEXT;
+
+	/** @var int flags, see self::FLAG_* constants */
+	private $flags = self::FLAG_NONE;
+
+	/**
+	 * @param string $name
+	 * @param string $text
+	 */
+	public function __construct($name, $text) {
+		$this->name = $name;
+		$this->text = $text;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getName() {
+		return $this->name;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getText() {
+		return $this->text;
+	}
+
+	/**
+	 * Get value type
+	 *
+	 * @return int
+	 */
+	public function getType() {
+		return $this->type;
+	}
+
+	/**
+	 * Set value type
+	 *
+	 * @param int $type
+	 * @return self
+	 */
+	public function setType($type) {
+		$this->type = $type;
+		return $this;
+	}
+
+	/**
+	 * @return int
+	 */
+	public function getFlags() {
+		return $this->flags;
+	}
+
+	/**
+	 * @param int $flags
+	 * @return self
+	 */
+	public function setFlags($flags) {
+		$this->flags = $flags;
+		return $this;
+	}
+
+	/**
+	 * @param int $flag
+	 * @return self
+	 */
+	public function setFlag($flag) {
+		$this->flags |= $flag;
+		return $this;
+	}
+
+	/**
+	 * @param int $flag
+	 * @return bool
+	 */
+	public function isFlagSet($flag) {
+		return (bool) $this->flags & $flag;
+	}
+
+	/**
+	 * Serialize into JSON for client-side JS
+	 *
+	 * @return string
+	 */
+	public function jsonSerialize() {
+		$prefix = '';
+		switch ($this->getType()) {
+			case self::VALUE_BOOLEAN:
+				$prefix = '!';
+				break;
+			case self::VALUE_PASSWORD:
+				$prefix = '*';
+				break;
+			case self::VALUE_HIDDEN:
+				$prefix = '#';
+				break;
+		}
+
+		switch ($this->getFlags()) {
+			case self::FLAG_OPTIONAL:
+				$prefix = '&' . $prefix;
+				break;
+		}
+
+		return $prefix . $this->getText();
+	}
+
+	/**
+	 * Validate a parameter value against this
+	 *
+	 * @param mixed $value Value to check
+	 * @return bool success
+	 */
+	public function validateValue($value) {
+		if ($this->getFlags() & self::FLAG_OPTIONAL) {
+			return true;
+		}
+		switch ($this->getType()) {
+		case self::VALUE_BOOLEAN:
+			if (!is_bool($value)) {
+				return false;
+			}
+			break;
+		default:
+			if (empty($value)) {
+				return false;
+			}
+			break;
+		}
+		return true;
+	}
+}
diff --git a/apps/files_external/lib/dependencytrait.php b/apps/files_external/lib/dependencytrait.php
new file mode 100644
index 00000000000..116421eab14
--- /dev/null
+++ b/apps/files_external/lib/dependencytrait.php
@@ -0,0 +1,86 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@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 OCA\Files_External\Lib;
+
+use \OCA\Files_External\Lib\MissingDependency;
+
+/**
+ * Trait for objects that have dependencies for use
+ */
+trait DependencyTrait {
+
+	/** @var callable|null dependency check */
+	private $dependencyCheck = null;
+
+	/**
+	 * @return bool
+	 */
+	public function hasDependencies() {
+		return !is_null($this->dependencyCheck);
+	}
+
+	/**
+	 * @param callable $dependencyCheck
+	 * @return self
+	 */
+	public function setDependencyCheck(callable $dependencyCheck) {
+		$this->dependencyCheck = $dependencyCheck;
+		return $this;
+	}
+
+	/**
+	 * Check if object is valid for use
+	 *
+	 * @return MissingDependency[] Unsatisfied dependencies
+	 */
+	public function checkDependencies() {
+		$ret = [];
+
+		if ($this->hasDependencies()) {
+			$result = call_user_func($this->dependencyCheck);
+			if ($result !== true) {
+				if (!is_array($result)) {
+					$result = [$result];
+				}
+				foreach ($result as $key => $value) {
+					if (!($value instanceof MissingDependency)) {
+						$module = null;
+						$message = null;
+						if (is_numeric($key)) {
+							$module = $value;
+						} else {
+							$module = $key;
+							$message = $value;
+						}
+						$value = new MissingDependency($module, $this);
+						$value->setMessage($message);
+					}
+					$ret[] = $value;
+				}
+			}
+		}
+
+		return $ret;
+	}
+
+}
+
diff --git a/apps/files_external/lib/frontenddefinitiontrait.php b/apps/files_external/lib/frontenddefinitiontrait.php
new file mode 100644
index 00000000000..4b826372d2f
--- /dev/null
+++ b/apps/files_external/lib/frontenddefinitiontrait.php
@@ -0,0 +1,147 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@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 OCA\Files_External\Lib;
+
+use \OCA\Files_External\Lib\DefinitionParameter;
+use \OCA\Files_External\Lib\StorageConfig;
+
+/**
+ * Trait for objects that have a frontend representation
+ */
+trait FrontendDefinitionTrait {
+
+	/** @var string human-readable mechanism name */
+	private $text;
+
+	/** @var DefinitionParameter[] parameters for mechanism */
+	private $parameters = [];
+
+	/** @var string|null custom JS */
+	private $customJs = null;
+
+	/**
+	 * @return string
+	 */
+	public function getText() {
+		return $this->text;
+	}
+
+	/**
+	 * @param string $text
+	 * @return self
+	 */
+	public function setText($text) {
+		$this->text = $text;
+		return $this;
+	}
+
+	/**
+	 * @param FrontendDefinitionTrait $a
+	 * @param FrontendDefinitionTrait $b
+	 * @return int
+	 */
+	public static function lexicalCompare(FrontendDefinitionTrait $a, FrontendDefinitionTrait $b) {
+		return strcmp($a->getText(), $b->getText());
+	}
+
+	/**
+	 * @return DefinitionParameter[]
+	 */
+	public function getParameters() {
+		return $this->parameters;
+	}
+
+	/**
+	 * @param DefinitionParameter[] $parameters
+	 * @return self
+	 */
+	public function addParameters(array $parameters) {
+		foreach ($parameters as $parameter) {
+			$this->addParameter($parameter);
+		}
+		return $this;
+	}
+
+	/**
+	 * @param DefinitionParameter $parameter
+	 * @return self
+	 */
+	public function addParameter(DefinitionParameter $parameter) {
+		$this->parameters[$parameter->getName()] = $parameter;
+		return $this;
+	}
+
+	/**
+	 * @return string|null
+	 */
+	public function getCustomJs() {
+		return $this->customJs;
+	}
+
+	/**
+	 * @param string $custom
+	 * @return self
+	 */
+	public function setCustomJs($custom) {
+		$this->customJs = $custom;
+		return $this;
+	}
+
+	/**
+	 * Serialize into JSON for client-side JS
+	 *
+	 * @return array
+	 */
+	public function jsonSerializeDefinition() {
+		$configuration = [];
+		foreach ($this->getParameters() as $parameter) {
+			$configuration[$parameter->getName()] = $parameter;
+		}
+
+		$data = [
+			'name' => $this->getText(),
+			'configuration' => $configuration,
+		];
+		if (isset($this->customJs)) {
+			$data['custom'] = $this->getCustomJs();
+		}
+		return $data;
+	}
+
+	/**
+	 * Check if parameters are satisfied in a StorageConfig
+	 *
+	 * @param StorageConfig $storage
+	 * @return bool
+	 */
+	public function validateStorageDefinition(StorageConfig $storage) {
+		$options = $storage->getBackendOptions();
+		foreach ($this->getParameters() as $name => $parameter) {
+			$value = isset($options[$name]) ? $options[$name] : null;
+			if (!$parameter->validateValue($value)) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+}
diff --git a/apps/files_external/lib/missingdependency.php b/apps/files_external/lib/missingdependency.php
new file mode 100644
index 00000000000..9b25aeacc9b
--- /dev/null
+++ b/apps/files_external/lib/missingdependency.php
@@ -0,0 +1,64 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@karoshi.org.uk>
+ *
+ * @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 OCA\Files_External\Lib;
+
+/**
+ * External storage backend dependency
+ */
+class MissingDependency {
+
+	/** @var string */
+	private $dependency;
+
+	/** @var string|null Custom message */
+	private $message = null;
+
+	/**
+	 * @param string $dependency
+	 */
+	public function __construct($dependency) {
+		$this->dependency = $dependency;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getDependency() {
+		return $this->dependency;
+	}
+
+	/**
+	 * @return string|null
+	 */
+	public function getMessage() {
+		return $this->message;
+	}
+
+	/**
+	 * @param string $message
+	 * @return self
+	 */
+	public function setMessage($message) {
+		$this->message = $message;
+		return $this;
+	}
+}
diff --git a/apps/files_external/lib/personalmount.php b/apps/files_external/lib/personalmount.php
index bbffc958641..d177f1a1ad0 100644
--- a/apps/files_external/lib/personalmount.php
+++ b/apps/files_external/lib/personalmount.php
@@ -20,15 +20,45 @@
  *
  */
 
-namespace OCA\Files_External;
+namespace OCA\Files_External\Lib;
 
 use OC\Files\Mount\MountPoint;
 use OC\Files\Mount\MoveableMount;
+use OCA\Files_External\Service\UserStoragesService;
 
 /**
  * Person mount points can be moved by the user
  */
 class PersonalMount extends MountPoint implements MoveableMount {
+	/** @var UserStoragesService */
+	protected $storagesService;
+
+	/** @var int */
+	protected $storageId;
+
+	/**
+	 * @param UserStoragesService $storagesService
+	 * @param int $storageId
+	 * @param string|\OC\Files\Storage\Storage $storage
+	 * @param string $mountpoint
+	 * @param array $arguments (optional) configuration for the storage backend
+	 * @param \OCP\Files\Storage\IStorageFactory $loader
+	 * @param array $mountOptions mount specific options
+	 */
+	public function __construct(
+		UserStoragesService $storagesService,
+		$storageId,
+		$storage,
+		$mountpoint,
+		$arguments = null,
+		$loader = null,
+		$mountOptions = null
+	) {
+		parent::__construct($storage, $mountpoint, $arguments, $loader, $mountOptions);
+		$this->storagesService = $storagesService;
+		$this->storageId = $storageId;
+	}
+
 	/**
 	 * Move the mount point to $target
 	 *
@@ -36,9 +66,13 @@ class PersonalMount extends MountPoint implements MoveableMount {
 	 * @return bool
 	 */
 	public function moveMount($target) {
-		$result = \OC_Mount_Config::movePersonalMountPoint($this->getMountPoint(), $target, \OC_Mount_Config::MOUNT_TYPE_USER);
+		$storage = $this->storagesService->getStorage($this->storageId);
+		// remove "/$user/files" prefix
+		$targetParts = explode('/', trim($target, '/'), 3);
+		$storage->setMountPoint($targetParts[2]);
+		$this->storagesService->updateStorage($storage);
 		$this->setMountPoint($target);
-		return $result;
+		return true;
 	}
 
 	/**
@@ -47,8 +81,7 @@ class PersonalMount extends MountPoint implements MoveableMount {
 	 * @return bool
 	 */
 	public function removeMount() {
-		$user = \OCP\User::getUser();
-		$relativeMountPoint = substr($this->getMountPoint(), strlen('/' . $user . '/files/'));
-		return \OC_Mount_Config::removeMountPoint($relativeMountPoint, \OC_Mount_Config::MOUNT_TYPE_USER, $user , true);
+		$this->storagesService->removeStorage($this->storageId);
+		return true;
 	}
 }
diff --git a/apps/files_external/lib/prioritytrait.php b/apps/files_external/lib/prioritytrait.php
new file mode 100644
index 00000000000..22f9fe275d8
--- /dev/null
+++ b/apps/files_external/lib/prioritytrait.php
@@ -0,0 +1,60 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@karoshi.org.uk>
+ *
+ * @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 OCA\Files_External\Lib;
+
+use \OCA\Files_External\Service\BackendService;
+
+/**
+ * Trait to implement priority mechanics for a configuration class
+ */
+trait PriorityTrait {
+
+	/** @var int initial priority */
+	protected $priority = BackendService::PRIORITY_DEFAULT;
+
+	/**
+	 * @return int
+	 */
+	public function getPriority() {
+		return $this->priority;
+	}
+
+	/**
+	 * @param int $priority
+	 * @return self
+	 */
+	public function setPriority($priority) {
+		$this->priority = $priority;
+		return $this;
+	}
+
+	/**
+	 * @param PriorityTrait $a
+	 * @param PriorityTrait $b
+	 * @return int
+	 */
+	public static function priorityCompare(PriorityTrait $a, PriorityTrait $b) {
+		return ($a->getPriority() - $b->getPriority());
+	}
+
+}
+
diff --git a/apps/files_external/lib/storageconfig.php b/apps/files_external/lib/storageconfig.php
index 92c27701d80..cf8271ff4eb 100644
--- a/apps/files_external/lib/storageconfig.php
+++ b/apps/files_external/lib/storageconfig.php
@@ -21,6 +21,8 @@
 
 namespace OCA\Files_external\Lib;
 
+use \OCA\Files_External\Lib\Backend\Backend;
+
 /**
  * External storage configuration
  */
@@ -34,11 +36,11 @@ class StorageConfig implements \JsonSerializable {
 	private $id;
 
 	/**
-	 * Backend class name
+	 * Backend
 	 *
-	 * @var string
+	 * @var Backend
 	 */
-	private $backendClass;
+	private $backend;
 
 	/**
 	 * Backend options
@@ -138,21 +140,17 @@ class StorageConfig implements \JsonSerializable {
 	}
 
 	/**
-	 * Returns the external storage backend class name
-	 *
-	 * @return string external storage backend class name
+	 * @return Backend
 	 */
-	public function getBackendClass() {
-		return $this->backendClass;
+	public function getBackend() {
+		return $this->backend;
 	}
 
 	/**
-	 * Sets the external storage backend class name
-	 *
-	 * @param string external storage backend class name
+	 * @param Backend
 	 */
-	public function setBackendClass($backendClass) {
-		$this->backendClass = $backendClass;
+	public function setBackend(Backend $backend) {
+		$this->backend= $backend;
 	}
 
 	/**
@@ -174,6 +172,25 @@ class StorageConfig implements \JsonSerializable {
 	}
 
 	/**
+	 * @param string $key
+	 * @return mixed
+	 */
+	public function getBackendOption($key) {
+		if (isset($this->backendOptions[$key])) {
+			return $this->backendOptions[$key];
+		}
+		return null;
+	}
+
+	/**
+	 * @param string $key
+	 * @param mixed $value
+	 */
+	public function setBackendOption($key, $value) {
+		$this->backendOptions[$key] = $value;
+	}
+
+	/**
 	 * Returns the mount priority
 	 *
 	 * @return int priority
@@ -283,7 +300,7 @@ class StorageConfig implements \JsonSerializable {
 			$result['id'] = $this->id;
 		}
 		$result['mountPoint'] = $this->mountPoint;
-		$result['backendClass'] = $this->backendClass;
+		$result['backendClass'] = $this->backend->getClass();
 		$result['backendOptions'] = $this->backendOptions;
 		if (!is_null($this->priority)) {
 			$result['priority'] = $this->priority;
diff --git a/apps/files_external/lib/storagemodifiertrait.php b/apps/files_external/lib/storagemodifiertrait.php
new file mode 100644
index 00000000000..f78116103db
--- /dev/null
+++ b/apps/files_external/lib/storagemodifiertrait.php
@@ -0,0 +1,51 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@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 OCA\Files_External\Lib;
+
+use \OCP\Files\Storage;
+use \OCA\Files_External\Lib\StorageConfig;
+
+/**
+ * Trait for objects that can modify StorageConfigs and wrap Storages
+ */
+trait StorageModifierTrait {
+
+	/**
+	 * Modify a StorageConfig parameters
+	 *
+	 * @param StorageConfig $storage
+	 */
+	public function manipulateStorageConfig(StorageConfig &$storage) {
+	}
+
+	/**
+	 * Wrap a Storage if necessary
+	 *
+	 * @param Storage $storage
+	 * @return Storage
+	 */
+	public function wrapStorage(Storage $storage) {
+		return $storage;
+	}
+
+}
+
diff --git a/apps/files_external/lib/visibilitytrait.php b/apps/files_external/lib/visibilitytrait.php
new file mode 100644
index 00000000000..06c95dd70c9
--- /dev/null
+++ b/apps/files_external/lib/visibilitytrait.php
@@ -0,0 +1,129 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@karoshi.org.uk>
+ *
+ * @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 OCA\Files_External\Lib;
+
+use \OCA\Files_External\Service\BackendService;
+
+/**
+ * Trait to implement visibility mechanics for a configuration class
+ */
+trait VisibilityTrait {
+
+	/** @var int visibility */
+	protected $visibility = BackendService::VISIBILITY_DEFAULT;
+
+	/** @var int allowed visibilities */
+	protected $allowedVisibility = BackendService::VISIBILITY_DEFAULT;
+
+	/**
+	 * @return int
+	 */
+	public function getVisibility() {
+		return $this->visibility;
+	}
+
+	/**
+	 * Check if the backend is visible for a user type
+	 *
+	 * @param int $visibility
+	 * @return bool
+	 */
+	public function isVisibleFor($visibility) {
+		if ($this->visibility & $visibility) {
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * @param int $visibility
+	 * @return self
+	 */
+	public function setVisibility($visibility) {
+		$this->visibility = $visibility;
+		$this->allowedVisibility |= $visibility;
+		return $this;
+	}
+
+	/**
+	 * @param int $visibility
+	 * @return self
+	 */
+	public function addVisibility($visibility) {
+		return $this->setVisibility($this->visibility | $visibility);
+	}
+
+	/**
+	 * @param int $visibility
+	 * @return self
+	 */
+	public function removeVisibility($visibility) {
+		return $this->setVisibility($this->visibility & ~$visibility);
+	}
+
+	/**
+	 * @return int
+	 */
+	public function getAllowedVisibility() {
+		return $this->allowedVisibility;
+	}
+
+	/**
+	 * Check if the backend is allowed to be visible for a user type
+	 *
+	 * @param int $allowedVisibility
+	 * @return bool
+	 */
+	public function isAllowedVisibleFor($allowedVisibility) {
+		if ($this->allowedVisibility & $allowedVisibility) {
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * @param int $allowedVisibility
+	 * @return self
+	 */
+	public function setAllowedVisibility($allowedVisibility) {
+		$this->allowedVisibility = $allowedVisibility;
+		$this->visibility &= $allowedVisibility;
+		return $this;
+	}
+
+	/**
+	 * @param int $allowedVisibility
+	 * @return self
+	 */
+	public function addAllowedVisibility($allowedVisibility) {
+		return $this->setAllowedVisibility($this->allowedVisibility | $allowedVisibility);
+	}
+
+	/**
+	 * @param int $allowedVisibility
+	 * @return self
+	 */
+	public function removeAllowedVisibility($allowedVisibility) {
+		return $this->setAllowedVisibility($this->allowedVisibility & ~$allowedVisibility);
+	}
+
+}