Add a wrapper to fall back to the share owner on public shares

Else it might happen that we setup a storage that has no real owner and
activities do boom etc (looking at you groupfolders and external
storages!).

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

apps/dav/appinfo/v1/publicwebdav.php

@@ -82,7 +82,9 @@ $server = $serverFactory->createServer($baseuri, $requestUri, $authPlugin, funct
 	\OC\Files\Filesystem::addStorageWrapper('sharePermissions', function ($mountPoint, $storage) use ($share) {
 		return new \OC\Files\Storage\Wrapper\PermissionsMask(['storage' => $storage, 'mask' => $share->getPermissions() | \OCP\Constants::PERMISSION_SHARE]);
 	});
-
+	\OC\Files\Filesystem::addStorageWrapper('shareOwner', function ($mountPoint, $storage) use ($share) {
+		return new \OCA\DAV\Storage\PublicOwnerWrapper(['storage' => $storage, 'owner' => $share->getShareOwner()]);
+	});
 	\OC\Files\Filesystem::logWarningWhenAddingStorageWrapper($previousLog);
 
 	OC_Util::tearDownFS();

apps/dav/composer/composer/autoload_classmap.php

@@ -210,6 +210,7 @@ return array(
     'OCA\\DAV\\RootCollection' => $baseDir . '/../lib/RootCollection.php',
     'OCA\\DAV\\Server' => $baseDir . '/../lib/Server.php',
     'OCA\\DAV\\Settings\\CalDAVSettings' => $baseDir . '/../lib/Settings/CalDAVSettings.php',
+    'OCA\\DAV\\Storage\\PublicOwnerWrapper' => $baseDir . '/../lib/Storage/PublicOwnerWrapper.php',
     'OCA\\DAV\\SystemTag\\SystemTagMappingNode' => $baseDir . '/../lib/SystemTag/SystemTagMappingNode.php',
     'OCA\\DAV\\SystemTag\\SystemTagNode' => $baseDir . '/../lib/SystemTag/SystemTagNode.php',
     'OCA\\DAV\\SystemTag\\SystemTagPlugin' => $baseDir . '/../lib/SystemTag/SystemTagPlugin.php',

apps/dav/composer/composer/autoload_static.php

@@ -225,6 +225,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\RootCollection' => __DIR__ . '/..' . '/../lib/RootCollection.php',
         'OCA\\DAV\\Server' => __DIR__ . '/..' . '/../lib/Server.php',
         'OCA\\DAV\\Settings\\CalDAVSettings' => __DIR__ . '/..' . '/../lib/Settings/CalDAVSettings.php',
+        'OCA\\DAV\\Storage\\PublicOwnerWrapper' => __DIR__ . '/..' . '/../lib/Storage/PublicOwnerWrapper.php',
         'OCA\\DAV\\SystemTag\\SystemTagMappingNode' => __DIR__ . '/..' . '/../lib/SystemTag/SystemTagMappingNode.php',
         'OCA\\DAV\\SystemTag\\SystemTagNode' => __DIR__ . '/..' . '/../lib/SystemTag/SystemTagNode.php',
         'OCA\\DAV\\SystemTag\\SystemTagPlugin' => __DIR__ . '/..' . '/../lib/SystemTag/SystemTagPlugin.php',

apps/dav/lib/Storage/PublicOwnerWrapper.php

@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2020, 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 OCA\DAV\Storage;
+
+use OC\Files\Storage\Wrapper\Wrapper;
+
+class PublicOwnerWrapper extends Wrapper {
+
+	/** @var string */
+	private $owner;
+
+	/**
+	 * @param array $arguments ['storage' => $storage, 'owner' => $owner]
+	 *
+	 * $storage: The storage the permissions mask should be applied on
+	 * $owner: The owner to use in case no owner is found
+	 */
+	public function __construct($arguments) {
+		parent::__construct($arguments);
+		$this->owner = $arguments['owner'];
+	}
+
+	public function getOwner($path) {
+		$owner = parent::getOwner($path);
+
+		if ($owner === null || $owner === false) {
+			return $this->owner;
+		}
+	}
+}