nextcloud/apps/files_sharing/lib/watcher.php

<?php
/**
 * @author Christopher Schäpers <kondou@ts.unde.re>
 * @author Michael Gapczynski <GapczynskiM@gmail.com>
 * @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\Cache;
use OCP\Files\Cache\ICacheEntry;

/**
 * check the storage backends for updates and change the cache accordingly
 */
class Shared_Watcher extends Watcher {
	/**
	 * @var \OC\Files\Storage\Shared $storage
	 */
	protected $storage;

	/**
	 * Update the cache for changes to $path
	 *
	 * @param string $path
	 * @param ICacheEntry $cachedData
	 */
	public function update($path, $cachedData) {
		parent::update($path, $cachedData);
		// since parent::update() has already updated the size of the subdirs,
		// only apply the update to the owner's parent dirs

		// find last parent before reaching the shared storage root,
		// which is the actual shared dir from the owner
		$sepPos = strpos($path, '/');
		if ($sepPos > 0) {
			$baseDir = substr($path, 0, $sepPos);
		} else {
			$baseDir = $path;
		}

		// find the path relative to the data dir
		$file = $this->storage->getFile($baseDir);
		$view = new \OC\Files\View('/' . $file['fileOwner']);

		// find the owner's storage and path
		/** @var \OC\Files\Storage\Storage $storage */
		list($storage, $internalPath) = $view->resolvePath($file['path']);

		// update the parent dirs' sizes in the owner's cache
		$storage->getCache()->correctFolderSize(dirname($internalPath));
	}

	/**
	 * remove deleted files in $path from the cache
	 *
	 * @param string $path
	 */
	public function cleanFolder($path) {
		if ($path != '') {
			parent::cleanFolder($path);
		}
	}

}