vendor/twig/twig/src/NodeTraverser.php line 53

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  1. <?php
  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. */
  12. namespace Twig;
  14. use Twig\Node\Node;
  15. use Twig\NodeVisitor\NodeVisitorInterface;
  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 = [];
  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. }
  40. public function addVisitor(NodeVisitorInterface $visitor): void
  41. {
  42. $this->visitors[$visitor->getPriority()][] = $visitor;
  43. }
  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. }
  57. return $node;
  58. }
  60. private function traverseForVisitor(NodeVisitorInterface $visitor, Node $node): ?Node
  61. {
  62. $node = $visitor->enterNode($node, $this->env);
  64. foreach ($node as $k => $n) {
  65. if (null !== $m = $this->traverseForVisitor($visitor, $n)) {
  66. if ($m !== $n) {
  67. $node->setNode($k, $m);
  68. }
  69. } else {
  70. $node->removeNode($k);
  71. }
  72. }
  74. return $visitor->leaveNode($node, $this->env);
  75. }
  76. }