inc/Twig/NodeVisitor/Sandbox.php

   1 <?php
   2
   3 /*
   4  * This file is part of Twig.
   5  *
   6  * (c) 2009 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 /**
  13  * Twig_NodeVisitor_Sandbox implements sandboxing.
  14  *
  15  * @author Fabien Potencier <fabien@symfony.com>
  16  */
  17 class Twig_NodeVisitor_Sandbox implements Twig_NodeVisitorInterface
  18 {
  19     protected $inAModule = false;
  20     protected $tags;
  21     protected $filters;
  22     protected $functions;
  23
  24     /**
  25      * Called before child nodes are visited.
  26      *
  27      * @param Twig_NodeInterface $node The node to visit
  28      * @param Twig_Environment   $env  The Twig environment instance
  29      *
  30      * @return Twig_NodeInterface The modified node
  31      */
  32     public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
  33     {
  34         if ($node instanceof Twig_Node_Module) {
  35             $this->inAModule = true;
  36             $this->tags = array();
  37             $this->filters = array();
  38             $this->functions = array();
  39
  40             return $node;
  41         } elseif ($this->inAModule) {
  42             // look for tags
  43             if ($node->getNodeTag()) {
  44                 $this->tags[] = $node->getNodeTag();
  45             }
  46
  47             // look for filters
  48             if ($node instanceof Twig_Node_Expression_Filter) {
  49                 $this->filters[] = $node->getNode('filter')->getAttribute('value');
  50             }
  51
  52             // look for functions
  53             if ($node instanceof Twig_Node_Expression_Function) {
  54                 $this->functions[] = $node->getAttribute('name');
  55             }
  56
  57             // wrap print to check __toString() calls
  58             if ($node instanceof Twig_Node_Print) {
  59                 return new Twig_Node_SandboxedPrint($node->getNode('expr'), $node->getLine(), $node->getNodeTag());
  60             }
  61         }
  62
  63         return $node;
  64     }
  65
  66     /**
  67      * Called after child nodes are visited.
  68      *
  69      * @param Twig_NodeInterface $node The node to visit
  70      * @param Twig_Environment   $env  The Twig environment instance
  71      *
  72      * @return Twig_NodeInterface The modified node
  73      */
  74     public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
  75     {
  76         if ($node instanceof Twig_Node_Module) {
  77             $this->inAModule = false;
  78
  79             return new Twig_Node_SandboxedModule($node, array_unique($this->filters), array_unique($this->tags), array_unique($this->functions));
  80         }
  81
  82         return $node;
  83     }
  84
  85     /**
  86      * {@inheritdoc}
  87      */
  88     public function getPriority()
  89     {
  90         return 0;
  91     }
  92 }