class CheckCircularReferencesPass

CheckCircularReferencesPassTest.php in drupal/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Compiler/CheckCircularReferencesPassTest.php

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 ServiceReferenceGraphEdge[] $edges An array of Edges
   *
   * @throws ServiceCircularReferenceException When a circular reference is found.
   */
  private function checkOutEdges(array $edges) {
    foreach ($edges as $edge) {
      $node = $edge
        ->getDestNode();
      $id = $node
        ->getId();
      $searchKey = array_search($id, $this->currentPath);
      $this->currentPath[] = $id;
      if (false !== $searchKey) {
        throw new ServiceCircularReferenceException($id, array_slice($this->currentPath, $searchKey));
      }
      $this
        ->checkOutEdges($node
        ->getOutEdges());
      array_pop($this->currentPath);
    }
  }

}