1 files changed, 107 insertions, 0 deletions
diff --git a/lib/private/Files/Storage/StorageFactory.php b/lib/private/Files/Storage/StorageFactory.php
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+++ b/lib/private/Files/Storage/StorageFactory.php
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+<?php
+/**
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ * @author Robin Appelman <icewind@owncloud.com>
+ * @author Vincent Petry <pvince81@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, 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 OC\Files\Storage;
+
+use OCP\Files\Mount\IMountPoint;
+use OCP\Files\Storage\IStorageFactory;
+
+class StorageFactory implements IStorageFactory {
+	/**
+	 * @var array[] [$name=>['priority'=>$priority, 'wrapper'=>$callable] $storageWrappers
+	 */
+	private $storageWrappers = [];
+
+	/**
+	 * allow modifier storage behaviour by adding wrappers around storages
+	 *
+	 * $callback should be a function of type (string $mountPoint, Storage $storage) => Storage
+	 *
+	 * @param string $wrapperName name of the wrapper
+	 * @param callable $callback callback
+	 * @param int $priority wrappers with the lower priority are applied last (meaning they get called first)
+	 * @param \OCP\Files\Mount\IMountPoint[] $existingMounts existing mount points to apply the wrapper to
+	 * @return bool true if the wrapper was added, false if there was already a wrapper with this
+	 * name registered
+	 */
+	public function addStorageWrapper($wrapperName, $callback, $priority = 50, $existingMounts = []) {
+		if (isset($this->storageWrappers[$wrapperName])) {
+			return false;
+		}
+
+		// apply to existing mounts before registering it to prevent applying it double in MountPoint::createStorage
+		foreach ($existingMounts as $mount) {
+			$mount->wrapStorage($callback);
+		}
+
+		$this->storageWrappers[$wrapperName] = ['wrapper' => $callback, 'priority' => $priority];
+		return true;
+	}
+
+	/**
+	 * Remove a storage wrapper by name.
+	 * Note: internal method only to be used for cleanup
+	 *
+	 * @param string $wrapperName name of the wrapper
+	 * @internal
+	 */
+	public function removeStorageWrapper($wrapperName) {
+		unset($this->storageWrappers[$wrapperName]);
+	}
+
+	/**
+	 * Create an instance of a storage and apply the registered storage wrappers
+	 *
+	 * @param \OCP\Files\Mount\IMountPoint $mountPoint
+	 * @param string $class
+	 * @param array $arguments
+	 * @return \OCP\Files\Storage
+	 */
+	public function getInstance(IMountPoint $mountPoint, $class, $arguments) {
+		return $this->wrap($mountPoint, new $class($arguments));
+	}
+
+	/**
+	 * @param \OCP\Files\Mount\IMountPoint $mountPoint
+	 * @param \OCP\Files\Storage $storage
+	 * @return \OCP\Files\Storage
+	 */
+	public function wrap(IMountPoint $mountPoint, $storage) {
+		$wrappers = array_values($this->storageWrappers);
+		usort($wrappers, function ($a, $b) {
+			return $b['priority'] - $a['priority'];
+		});
+		/** @var callable[] $wrappers */
+		$wrappers = array_map(function ($wrapper) {
+			return $wrapper['wrapper'];
+		}, $wrappers);
+		foreach ($wrappers as $wrapper) {
+			$storage = $wrapper($mountPoint->getMountPoint(), $storage, $mountPoint);
+			if (!($storage instanceof \OCP\Files\Storage)) {
+				throw new \Exception('Invalid result from storage wrapper');
+			}
+		}
+		return $storage;
+	}
+}