[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  /*
   4   * This file is part of Twig.
   5   *
   6   * (c) Fabien Potencier
   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 Twig;
  13  
  14  use Twig\Node\Node;
  15  use Twig\NodeVisitor\NodeVisitorInterface;
  16  
  17  /**
  18   * A node traverser.
  19   *
  20   * It visits all nodes and their children and calls the given visitor for each.
  21   *
  22   * @author Fabien Potencier <fabien@symfony.com>
  23   */
  24  final class NodeTraverser
  25  {
  26      private $env;
  27      private $visitors = [];
  28  
  29      /**
  30       * @param NodeVisitorInterface[] $visitors
  31       */
  32      public function __construct(Environment $env, array $visitors = [])
  33      {
  34          $this->env = $env;
  35          foreach ($visitors as $visitor) {
  36              $this->addVisitor($visitor);
  37          }
  38      }
  39  
  40      public function addVisitor(NodeVisitorInterface $visitor)
  41      {
  42          $this->visitors[$visitor->getPriority()][] = $visitor;
  43      }
  44  
  45      /**
  46       * Traverses a node and calls the registered visitors.
  47       */
  48      public function traverse(Node $node): Node
  49      {
  50          ksort($this->visitors);
  51          foreach ($this->visitors as $visitors) {
  52              foreach ($visitors as $visitor) {
  53                  $node = $this->traverseForVisitor($visitor, $node);
  54              }
  55          }
  56  
  57          return $node;
  58      }
  59  
  60      /**
  61       * @return Node|null
  62       */
  63      private function traverseForVisitor(NodeVisitorInterface $visitor, Node $node)
  64      {
  65          $node = $visitor->enterNode($node, $this->env);
  66  
  67          foreach ($node as $k => $n) {
  68              if (false !== ($m = $this->traverseForVisitor($visitor, $n)) && null !== $m) {
  69                  if ($m !== $n) {
  70                      $node->setNode($k, $m);
  71                  }
  72              } else {
  73                  if (false === $m) {
  74                      @trigger_error('Returning "false" to remove a Node from NodeVisitorInterface::leaveNode() is deprecated since Twig version 2.9; return "null" instead.', \E_USER_DEPRECATED);
  75                  }
  76  
  77                  $node->removeNode($k);
  78              }
  79          }
  80  
  81          return $visitor->leaveNode($node, $this->env);
  82      }
  83  }
  84  
  85  class_alias('Twig\NodeTraverser', 'Twig_NodeTraverser');