1 <?php

     2 

     3 /*

     4  * This file is part of the Symfony framework.

     5  *

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

     7  *

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

     9  * with this source code in the file LICENSE.

    10  */

    11 

    12 namespace Symfony\Component\DependencyInjection\Compiler;

    13 

    14 use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;

    15 use Symfony\Component\DependencyInjection\ContainerBuilder;

    16 

    17 /**

    18  * Checks your services for circular references

    19  *

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

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

    22  *

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

    24  *

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

    26  */

    27 class CheckCircularReferencesPass implements CompilerPassInterface

    28 {

    29     private $currentId;

    30     private $currentPath;

    31 

    32     /**

    33      * Checks the ContainerBuilder object for circular references.

    34      *

    35      * @param ContainerBuilder $container The ContainerBuilder instances

    36      */

    37     public function process(ContainerBuilder $container)

    38     {

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

    40 

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

    42             $this->currentId = $id;

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

    44 

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

    46         }

    47     }

    48 

    49     /**

    50      * Checks for circular references.

    51      *

    52      * @param array $edges An array of Nodes

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

    54      */

    55     private function checkOutEdges(array $edges)

    56     {

    57         foreach ($edges as $edge) {

    58             $node = $edge->getDestNode();

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

    60 

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

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

    63             }

    64 

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

    66             array_pop($this->currentPath);

    67         }

    68     }

    69 }