owncloud/core

<?php
/**
 * @author Andreas Fischer <bantu@owncloud.com>
 * @author Georg Ehrke <georg@owncloud.com>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Markus Goetz <markus@woboq.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Roeland Jago Douma <rullzer@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;

use \OCP\AutoloadNotAllowedException;

class Autoloader {
    /** @var array */
    private $validRoots = [];

    /**
     * Optional low-latency memory cache for class to path mapping.
     *
     * @var \OC\Memcache\Cache
     */
    protected $memoryCache;

    /**
     * Autoloader constructor.
     *
     * @param string[] $validRoots
     */
    public function __construct(array $validRoots = []) {
        foreach ($validRoots as $root) {
            $this->validRoots[$root] = true;
        }
    }

    /**
     * Add a path to the list of valid php roots for auto loading
     *
     * @param string $root
     */
    public function addValidRoot($root) {
        $root = \stream_resolve_include_path($root);
        $this->validRoots[$root] = true;
    }

    /**
     * get the possible paths for a class
     *
     * @param string $class
     * @return array|bool an array of possible paths or false if the class is not part of ownCloud
     */
    public function findClass($class) {
        $class = \trim($class, '\\');

        $paths = [];
        if (\strpos($class, 'OCA\\') === 0) {
            list(, $app, $rest) = \explode('\\', $class, 3);
            $app = \strtolower($app);
            $appPath = \OC_App::getAppPath($app);
            if ($appPath && \stream_resolve_include_path($appPath)) {
                $paths[] = $appPath . '/' . \strtolower(\str_replace('\\', '/', $rest) . '.php');
                // If not found in the root of the app directory, insert '/lib' after app id and try again.
                $paths[] = $appPath . '/lib/' . \strtolower(\str_replace('\\', '/', $rest) . '.php');
            }
        }
        return $paths;
    }

    /**
     * @param string $fullPath
     * @return bool
     */
    protected function isValidPath($fullPath) {
        foreach ($this->validRoots as $root => $true) {
            if (\substr($fullPath, 0, \strlen($root) + 1) === $root . '/') {
                return true;
            }
        }
        throw new AutoloadNotAllowedException($fullPath);
    }

    /**
     * Load the specified class
     *
     * @param string $class
     * @return bool
     */
    public function load($class) {
        $pathsToRequire = null;
        if ($this->memoryCache) {
            $pathsToRequire = $this->memoryCache->get($class);
        }

        if (\class_exists($class, false)) {
            return false;
        }

        if (!\is_array($pathsToRequire)) {
            // No cache or cache miss
            $pathsToRequire = [];
            foreach ($this->findClass($class) as $path) {
                $fullPath = \stream_resolve_include_path($path);
                if ($fullPath && $this->isValidPath($fullPath)) {
                    $pathsToRequire[] = $fullPath;
                }
            }

            if ($this->memoryCache) {
                $this->memoryCache->set($class, $pathsToRequire, 60); // cache 60 sec
            }
        }

        foreach ($pathsToRequire as $fullPath) {
            require_once $fullPath;
        }

        return false;
    }

    /**
     * Sets the optional low-latency cache for class to path mapping.
     *
     * @param \OC\Memcache\Cache $memoryCache Instance of memory cache.
     */
    public function setMemoryCache(\OC\Memcache\Cache $memoryCache = null) {
        $this->memoryCache = $memoryCache;
    }
}