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   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <fabien@symfony.com>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\DependencyInjection\Compiler;
  13  
  14  use Symfony\Component\DependencyInjection\ContainerBuilder;
  15  use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;
  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 $currentPath;
  30      private $checkedNodes;
  31  
  32      /**
  33       * Checks the ContainerBuilder object for circular references.
  34       */
  35      public function process(ContainerBuilder $container)
  36      {
  37          $graph = $container->getCompiler()->getServiceReferenceGraph();
  38  
  39          $this->checkedNodes = array();
  40          foreach ($graph->getNodes() as $id => $node) {
  41              $this->currentPath = array($id);
  42  
  43              $this->checkOutEdges($node->getOutEdges());
  44          }
  45      }
  46  
  47      /**
  48       * Checks for circular references.
  49       *
  50       * @param ServiceReferenceGraphEdge[] $edges An array of Edges
  51       *
  52       * @throws ServiceCircularReferenceException when a circular reference is found
  53       */
  54      private function checkOutEdges(array $edges)
  55      {
  56          foreach ($edges as $edge) {
  57              $node = $edge->getDestNode();
  58              $id = $node->getId();
  59  
  60              if (empty($this->checkedNodes[$id])) {
  61                  // don't check circular dependencies for lazy services
  62                  if (!$node->getValue() || !$node->getValue()->isLazy()) {
  63                      $searchKey = array_search($id, $this->currentPath);
  64                      $this->currentPath[] = $id;
  65  
  66                      if (false !== $searchKey) {
  67                          throw new ServiceCircularReferenceException($id, \array_slice($this->currentPath, $searchKey));
  68                      }
  69  
  70                      $this->checkOutEdges($node->getOutEdges());
  71                  }
  72  
  73                  $this->checkedNodes[$id] = true;
  74                  array_pop($this->currentPath);
  75              }
  76          }
  77      }
  78  }