owncloud/core

<?php
/**
 * @author Daniel Jagszent <daniel@jagszent.de>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Vincent Petry <pvince81@owncloud.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @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;
use OCP\Files\Cache\IWatcher;

/**
 * check the storage backends for updates and change the cache accordingly
 */
class Watcher implements IWatcher {
    protected $watchPolicy = self::CHECK_ONCE;

    protected $checkedPaths = [];

    /**
     * @var \OC\Files\Storage\Storage $storage
     */
    protected $storage;

    /**
     * @var Cache $cache
     */
    protected $cache;

    /**
     * @var Scanner $scanner ;
     */
    protected $scanner;

    /**
     * @param \OC\Files\Storage\Storage $storage
     */
    public function __construct(\OC\Files\Storage\Storage $storage) {
        $this->storage = $storage;
        $this->cache = $storage->getCache();
        $this->scanner = $storage->getScanner();
    }

    /**
     * @param int $policy either \OC\Files\Cache\Watcher::CHECK_NEVER, \OC\Files\Cache\Watcher::CHECK_ONCE, \OC\Files\Cache\Watcher::CHECK_ALWAYS
     */
    public function setPolicy($policy) {
        $this->watchPolicy = $policy;
    }

    /**
     * @return int either \OC\Files\Cache\Watcher::CHECK_NEVER, \OC\Files\Cache\Watcher::CHECK_ONCE, \OC\Files\Cache\Watcher::CHECK_ALWAYS
     */
    public function getPolicy() {
        return $this->watchPolicy;
    }

    /**
     * check $path for updates and update if needed
     *
     * @param string $path
     * @param ICacheEntry|null $cachedEntry
     * @return boolean true if path was updated
     */
    public function checkUpdate($path, $cachedEntry = null) {
        if ($cachedEntry === null) {
            $cachedEntry = $this->cache->get($path);
        }
        if ($this->needsUpdate($path, $cachedEntry)) {
            $this->update($path, $cachedEntry);
            return true;
        } else {
            return false;
        }
    }

    /**
     * Update the cache for changes to $path
     *
     * @param string $path
     * @param ICacheEntry|bool $cachedData false if there is currently no cached data
     */
    public function update($path, $cachedData) {
        if ($this->storage->is_dir($path)) {
            $this->scanner->scan($path, Scanner::SCAN_SHALLOW, Scanner::REUSE_ETAG | Scanner::REUSE_SIZE | Scanner::REUSE_ONLY_FOR_FILES);
        } else {
            $this->scanner->scanFile($path);
        }
        if ((isset($cachedData['mimetype'])) && ($cachedData['mimetype'] === 'httpd/unix-directory')) {
            $this->cleanFolder($path);
        }
        if ($this->cache instanceof Cache) {
            $this->cache->correctFolderSize($path);
        }
    }

    /**
     * Check if the cache for $path needs to be updated
     *
     * @param string $path
     * @param ICacheEntry|bool $cachedData false if there is currently no cached data
     * @return bool
     */
    public function needsUpdate($path, $cachedData) {
        if ($this->watchPolicy === self::CHECK_ALWAYS or ($this->watchPolicy === self::CHECK_ONCE and \array_search($path, $this->checkedPaths) === false)) {
            $this->checkedPaths[] = $path;
            if (isset($cachedData['storage_mtime'])) {
                $storageMtime = $cachedData['storage_mtime'];
            } else {
                $storageMtime = 0;
            }
            return $this->storage->hasUpdated($path, $storageMtime);
        }
        return false;
    }

    /**
     * remove deleted files in $path from the cache
     *
     * @param string $path
     */
    public function cleanFolder($path) {
        $cachedContent = $this->cache->getFolderContents($path);
        foreach ($cachedContent as $entry) {
            if (!$this->storage->file_exists($entry['path'])) {
                $this->cache->remove($entry['path']);
            }
        }
    }
}