<?php

/*

 * This file is part of the Symfony framework.

 *

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

 *

 * This source file is subject to the MIT license that is bundled

 * with this source code in the file LICENSE.

 */

namespace Symfony\Component\DependencyInjection\Compiler;

use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;

use Symfony\Component\DependencyInjection\ContainerBuilder;

/**

 * Checks your services for circular references

 *

 * References from method calls are ignored since we might be able to resolve

 * these references depending on the order in which services are called.

 *

 * Circular reference from method calls will only be detected at run-time.

 *

 * @author Johannes M. Schmitt <schmittjoh@gmail.com>

 */

class CheckCircularReferencesPass implements CompilerPassInterface

{

    private $currentId;

    private $currentPath;

    /**

     * Checks the ContainerBuilder object for circular references.

     *

     * @param ContainerBuilder $container The ContainerBuilder instances

     */

    public function process(ContainerBuilder $container)

    {

        $graph = $container->getCompiler()->getServiceReferenceGraph();

        foreach ($graph->getNodes() as $id => $node) {

            $this->currentId = $id;

            $this->currentPath = array($id);

            $this->checkOutEdges($node->getOutEdges());

        }

    }

    /**

     * Checks for circular references.

     *

     * @param array $edges An array of Nodes

     * @throws \RuntimeException When a circular reference is found.

     */

    private function checkOutEdges(array $edges)

    {

        foreach ($edges as $edge) {

            $node = $edge->getDestNode();

            $this->currentPath[] = $id = $node->getId();

            if ($this->currentId === $id) {

                throw new ServiceCircularReferenceException($this->currentId, $this->currentPath);

            }

            $this->checkOutEdges($node->getOutEdges());

            array_pop($this->currentPath);

        }

    }

}