<?php

/*

 * This file is part of the Symfony package.

 *

 * (c) Fabien Potencier <fabien@symfony.com>

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace Symfony\Component\ClassLoader;

/**

 * ApcUniversalClassLoader implements a "universal" autoloader cached in APC for PHP 5.3.

 *

 * It is able to load classes that use either:

 *

 *  * The technical interoperability standards for PHP 5.3 namespaces and

 *    class names (http://groups.google.com/group/php-standards/web/psr-0-final-proposal);

 *

 *  * The PEAR naming convention for classes (http://pear.php.net/).

 *

 * Classes from a sub-namespace or a sub-hierarchy of PEAR classes can be

 * looked for in a list of locations to ease the vendoring of a sub-set of

 * classes for large projects.

 *

 * Example usage:

 *

 *     require 'vendor/symfony/src/Symfony/Component/ClassLoader/UniversalClassLoader.php';

 *     require 'vendor/symfony/src/Symfony/Component/ClassLoader/ApcUniversalClassLoader.php';

 *

 *     use Symfony\Component\ClassLoader\ApcUniversalClassLoader;

 *

 *     $loader = new ApcUniversalClassLoader('apc.prefix.');

 *

 *     // register classes with namespaces

 *     $loader->registerNamespaces(array(

 *         'Symfony\Component' => __DIR__.'/component',

 *         'Symfony'           => __DIR__.'/framework',

 *         'Sensio'            => array(__DIR__.'/src', __DIR__.'/vendor'),

 *     ));

 *

 *     // register a library using the PEAR naming convention

 *     $loader->registerPrefixes(array(

 *         'Swift_' => __DIR__.'/Swift',

 *     ));

 *

 *     // activate the autoloader

 *     $loader->register();

 *

 * In this example, if you try to use a class in the Symfony\Component

 * namespace or one of its children (Symfony\Component\Console for instance),

 * the autoloader will first look for the class under the component/

 * directory, and it will then fallback to the framework/ directory if not

 * found before giving up.

 *

 * @author Fabien Potencier <fabien@symfony.com>

 * @author Kris Wallsmith <kris@symfony.com>

 *

 * @api

 */

class ApcUniversalClassLoader extends UniversalClassLoader

{

    private $prefix;

    /**

     * Constructor.

     *

     * @param string $prefix A prefix to create a namespace in APC

     *

     * @api

     */

    public function __construct($prefix)

    {

        if (!extension_loaded('apc')) {

            throw new \RuntimeException('Unable to use ApcUniversalClassLoader as APC is not enabled.');

        }

        $this->prefix = $prefix;

    }

    /**

     * Finds a file by class name while caching lookups to APC.

     *

     * @param string $class A class name to resolve to file

     */

    public function findFile($class)

    {

        if (false === $file = apc_fetch($this->prefix.$class)) {

            apc_store($this->prefix.$class, $file = parent::findFile($class));

        }

        return $file;

    }

}