diff -r 6d109e3804ac -r 9a001a04b634 Twig-1.3.0/lib/Twig/NodeVisitor/Escaper.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Twig-1.3.0/lib/Twig/NodeVisitor/Escaper.php	Tue Oct 25 23:56:28 2011 +0200
@@ -0,0 +1,161 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) 2009 Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Twig_NodeVisitor_Escaper implements output escaping.
+ *
+ * @package    twig
+ * @author     Fabien Potencier <fabien@symfony.com>
+ */
+class Twig_NodeVisitor_Escaper implements Twig_NodeVisitorInterface
+{
+    protected $statusStack = array();
+    protected $blocks = array();
+
+    protected $safeAnalysis;
+    protected $traverser;
+
+    function __construct()
+    {
+        $this->safeAnalysis = new Twig_NodeVisitor_SafeAnalysis();
+    }
+
+    /**
+     * Called before child nodes are visited.
+     *
+     * @param Twig_NodeInterface $node The node to visit
+     * @param Twig_Environment   $env  The Twig environment instance
+     *
+     * @param Twig_NodeInterface The modified node
+     */
+    public function enterNode(Twig_NodeInterface $node, Twig_Environment $env)
+    {
+        if ($node instanceof Twig_Node_AutoEscape) {
+            $this->statusStack[] = $node->getAttribute('value');
+        } elseif ($node instanceof Twig_Node_Block) {
+            $this->statusStack[] = isset($this->blocks[$node->getAttribute('name')]) ? $this->blocks[$node->getAttribute('name')] : $this->needEscaping($env);
+        }
+
+        return $node;
+    }
+
+    /**
+     * Called after child nodes are visited.
+     *
+     * @param Twig_NodeInterface $node The node to visit
+     * @param Twig_Environment   $env  The Twig environment instance
+     *
+     * @param Twig_NodeInterface The modified node
+     */
+    public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env)
+    {
+        if ($node instanceof Twig_Node_Expression_Filter) {
+            return $this->preEscapeFilterNode($node, $env);
+        } elseif ($node instanceof Twig_Node_Print) {
+            return $this->escapePrintNode($node, $env, $this->needEscaping($env));
+        }
+
+        if ($node instanceof Twig_Node_AutoEscape || $node instanceof Twig_Node_Block) {
+            array_pop($this->statusStack);
+        } elseif ($node instanceof Twig_Node_BlockReference) {
+            $this->blocks[$node->getAttribute('name')] = $this->needEscaping($env);
+        }
+
+        return $node;
+    }
+
+    protected function escapePrintNode(Twig_Node_Print $node, Twig_Environment $env, $type)
+    {
+        if (false === $type) {
+            return $node;
+        }
+
+        $expression = $node->getNode('expr');
+
+        if ($this->isSafeFor($type, $expression, $env)) {
+            return $node;
+        }
+
+        $class = get_class($node);
+
+        return new $class(
+            $this->getEscaperFilter($type, $expression),
+            $node->getLine()
+        );
+    }
+
+    protected function preEscapeFilterNode(Twig_Node_Expression_Filter $filter, Twig_Environment $env)
+    {
+        $name = $filter->getNode('filter')->getAttribute('value');
+
+        if (false !== $f = $env->getFilter($name)) {
+            $type = $f->getPreEscape();
+            if (null === $type) {
+                return $filter;
+            }
+
+            $node = $filter->getNode('node');
+            if ($this->isSafeFor($type, $node, $env)) {
+                return $filter;
+            }
+
+            $filter->setNode('node', $this->getEscaperFilter($type, $node));
+
+            return $filter;
+        }
+
+        return $filter;
+    }
+
+    protected function isSafeFor($type, Twig_NodeInterface $expression, $env)
+    {
+        $safe = $this->safeAnalysis->getSafe($expression);
+
+        if (null === $safe) {
+            if (null === $this->traverser) {
+                $this->traverser = new Twig_NodeTraverser($env, array($this->safeAnalysis));
+            }
+            $this->traverser->traverse($expression);
+            $safe = $this->safeAnalysis->getSafe($expression);
+        }
+
+        return in_array($type, $safe) || in_array('all', $safe);
+    }
+
+    protected function needEscaping(Twig_Environment $env)
+    {
+        if (count($this->statusStack)) {
+            return $this->statusStack[count($this->statusStack) - 1];
+        }
+
+        if ($env->hasExtension('escaper') && $env->getExtension('escaper')->isGlobal()) {
+            return 'html';
+        }
+
+        return false;
+    }
+
+    protected function getEscaperFilter($type, Twig_NodeInterface $node)
+    {
+        $line = $node->getLine();
+        $name = new Twig_Node_Expression_Constant('escape', $line);
+        $args = new Twig_Node(array(new Twig_Node_Expression_Constant((string) $type, $line), new Twig_Node_Expression_Constant(null, $line), new Twig_Node_Expression_Constant(true, $line)));
+        return new Twig_Node_Expression_Filter($node, $name, $args, $line);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getPriority()
+    {
+        return 0;
+    }
+}