Added "pre_escape" option for filters

This allows filters to get their input pre-escaped for a given context

lib/Twig/Filter.php

@@ -48,4 +48,13 @@ abstract class Twig_Filter implements Twig_FilterInterface
 
         return array();
     }
+
+    public function getPreEscape()
+    {
+        if (isset($this->options['pre_escape'])) {
+            return $this->options['pre_escape'];
+        }
+
+        return null;
+    }
 }

lib/Twig/FilterInterface.php

@@ -18,4 +18,7 @@
 interface Twig_FilterInterface
 {
     public function compile();
+    public function needsEnvironment();
+    public function getSafe(Twig_Node $filterArgs);
+    public function getPreEscape();
 }

lib/Twig/NodeVisitor/Escaper.php

@@ -40,8 +40,6 @@ class Twig_NodeVisitor_Escaper implements Twig_NodeVisitorInterface
     {
         if ($node instanceof Twig_Node_AutoEscape) {
             $this->statusStack[] = $node->getAttribute('value');
-        } elseif ($node instanceof Twig_Node_Print) {
-            return $this->escapeNode($node, $env, $this->needEscaping($env));
         } elseif ($node instanceof Twig_Node_Block) {
             $this->statusStack[] = isset($this->blocks[$node->getAttribute('name')]) ? $this->blocks[$node->getAttribute('name')] : $this->needEscaping($env);
         }
@@ -59,6 +57,12 @@ class Twig_NodeVisitor_Escaper implements Twig_NodeVisitorInterface
      */
     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) {
@@ -68,14 +72,50 @@ class Twig_NodeVisitor_Escaper implements Twig_NodeVisitorInterface
         return $node;
     }
 
-    protected function escapeNode(Twig_NodeInterface $node, Twig_Environment $env, $type)
+    protected function escapePrintNode(Twig_Node_Print $node, Twig_Environment $env, $type)
     {
         if (false === $type) {
             return $node;
         }
 
-        $expression = $node instanceof Twig_Node_Print ? $node->getNode('expr') : $node;
+        $expression = $node->getNode('expr');
 
+        if ($this->isSafeFor($type, $expression, $env)) {
+            return $node;
+        }
+
+        return new Twig_Node_Print(
+            $this->getEscaperFilter($type, $expression),
+            $node->getLine()
+        );
+    }
+
+    protected function preEscapeFilterNode(Twig_Node_Expression_Filter $filter, Twig_Environment $env)
+    {
+        $filterMap = $env->getFilters();
+        $name = $filter->getNode('filter')->getAttribute('value');
+
+        if (isset($filterMap[$name])) {
+            $type = $filterMap[$name]->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) {
@@ -86,18 +126,7 @@ class Twig_NodeVisitor_Escaper implements Twig_NodeVisitorInterface
             $safe = $this->safeAnalysis->getSafe($expression);
         }
 
-        if (false !== in_array($type, $safe) || false !== in_array('all', $safe)) {
-            return $node;
-        }
-
-        if ($node instanceof Twig_Node_Print) {
-            return new Twig_Node_Print(
-                $this->getEscaperFilter($type, $expression),
-                $node->getLine()
-            );
-        }
-
-        return $this->getEscaperFilter($type, $node);
+        return in_array($type, $safe) || in_array('all', $safe);
     }
 
     protected function needEscaping(Twig_Environment $env)

test/Twig/Tests/Fixtures/tags/autoescape/with_filters.test

@@ -3,22 +3,22 @@
 --TEMPLATE--
 {% autoescape on %}
 
-(nl2br is an escaper filter)
+(escape_and_nl2br is an escaper filter)
 
 1. Don't escape escaper filter output
-( var is escaped by |nl2br, line-breaks are added, 
+( var is escaped by |escape_and_nl2br, line-breaks are added, 
   the output is not escaped )
-{{ var|nl2br }}
+{{ var|escape_and_nl2br }}
 
 2. Don't escape escaper filter output
-( var is escaped by |nl2br, line-breaks are added, 
+( var is escaped by |escape_and_nl2br, line-breaks are added, 
   the output is not escaped, |raw is redundant )
-{{ var|nl2br|raw }}
+{{ var|escape_and_nl2br|raw }}
 
 3. Explicit escape
-( var is escaped by |nl2br, line-breaks are added,
+( var is escaped by |escape_and_nl2br, line-breaks are added,
   the output is explicitly escaped by |escape )
-{{ var|nl2br|escape }}
+{{ var|escape_and_nl2br|escape }}
 
 4. Escape non-escaper filter output
 ( var is upper-cased by |upper,
@@ -26,16 +26,16 @@
 {{ var|upper }}
 
 5. Escape if last filter is not an escaper
-( var is escaped by |nl2br, line-breaks are added,
+( var is escaped by |escape_and_nl2br, line-breaks are added,
   the output is upper-cased by |upper,
   the output is auto-escaped as |upper is not an escaper )
-{{ var|nl2br|upper }}
+{{ var|escape_and_nl2br|upper }}
 
 6. Don't escape escaper filter output
 ( var is upper cased by upper,
-  the output is escaped by |nl2br, line-breaks are added,
-  the output is not escaped as |nl2br is an escaper )
-{{ var|upper|nl2br }}
+  the output is escaped by |escape_and_nl2br, line-breaks are added,
+  the output is not escaped as |escape_and_nl2br is an escaper )
+{{ var|upper|escape_and_nl2br }}
 
 7. Escape if last filter is not an escaper
 ( the output of |format is "<b>" ~ var ~ "</b>",
@@ -64,22 +64,22 @@
 return array('var' => "<Fabien>\nTwig")
 --EXPECT--
 
-(nl2br is an escaper filter)
+(escape_and_nl2br is an escaper filter)
 
 1. Don't escape escaper filter output
-( var is escaped by |nl2br, line-breaks are added, 
+( var is escaped by |escape_and_nl2br, line-breaks are added, 
   the output is not escaped )
 &lt;Fabien&gt;<br />
 Twig
 
 2. Don't escape escaper filter output
-( var is escaped by |nl2br, line-breaks are added, 
+( var is escaped by |escape_and_nl2br, line-breaks are added, 
   the output is not escaped, |raw is redundant )
 &lt;Fabien&gt;<br />
 Twig
 
 3. Explicit escape
-( var is escaped by |nl2br, line-breaks are added,
+( var is escaped by |escape_and_nl2br, line-breaks are added,
   the output is explicitly escaped by |escape )
 &amp;lt;Fabien&amp;gt;&lt;br /&gt;
 Twig
@@ -91,7 +91,7 @@ Twig
 TWIG
 
 5. Escape if last filter is not an escaper
-( var is escaped by |nl2br, line-breaks are added,
+( var is escaped by |escape_and_nl2br, line-breaks are added,
   the output is upper-cased by |upper,
   the output is auto-escaped as |upper is not an escaper )
 &amp;LT;FABIEN&amp;GT;&lt;BR /&gt;
@@ -99,8 +99,8 @@ TWIG
 
 6. Don't escape escaper filter output
 ( var is upper cased by upper,
-  the output is escaped by |nl2br, line-breaks are added,
-  the output is not escaped as |nl2br is an escaper )
+  the output is escaped by |escape_and_nl2br, line-breaks are added,
+  the output is not escaped as |escape_and_nl2br is an escaper )
 &lt;FABIEN&gt;<br />
 TWIG
 

test/Twig/Tests/Fixtures/tags/autoescape/with_pre_escape_filters.test

@@ -0,0 +1,68 @@
+--TEST--
+"autoescape" tag applies escaping after calling filters, and before calling pre_escape filters
+--TEMPLATE--
+{% autoescape on %}
+
+(nl2br is pre_escaped for "html" and declared safe for "html")
+
+1. Pre-escape and don't post-escape
+( var|escape|nl2br )
+{{ var|nl2br }}
+
+2. Don't double-pre-escape
+( var|escape|nl2br )
+{{ var|escape|nl2br }}
+
+3. Don't escape safe values
+( var|raw|nl2br )
+{{ var|raw|nl2br }}
+
+4. Don't escape safe values
+( var|escape|nl2br|nl2br )
+{{ var|nl2br|nl2br }}
+
+5. Re-escape values that are escaped for an other contexts
+( var|escape_something|escape|nl2br )
+{{ var|escape_something|nl2br }}
+
+6. Still escape when using filters not declared safe
+( var|escape|nl2br|upper|escape )
+{{ var|nl2br|upper }}
+
+{% endautoescape %}
+--DATA--
+return array('var' => "<Fabien>\nTwig")
+--EXPECT--
+
+(nl2br is pre_escaped for "html" and declared safe for "html")
+
+1. Pre-escape and don't post-escape
+( var|escape|nl2br )
+&lt;Fabien&gt;<br />
+Twig
+
+2. Don't double-pre-escape
+( var|escape|nl2br )
+&lt;Fabien&gt;<br />
+Twig
+
+3. Don't escape safe values
+( var|raw|nl2br )
+<Fabien><br />
+Twig
+
+4. Don't escape safe values
+( var|escape|nl2br|nl2br )
+&lt;Fabien&gt;<br /><br />
+Twig
+
+5. Re-escape values that are escaped for an other contexts
+( var|escape_something|escape|nl2br )
+&lt;FABIEN&gt;<br />
+TWIG
+
+6. Still escape when using filters not declared safe
+( var|escape|nl2br|upper|escape )
+&amp;LT;FABIEN&amp;GT;&lt;BR /&gt;
+TWIG
+

test/Twig/Tests/integrationTest.php

@@ -103,12 +103,34 @@ class TestExtension extends Twig_Extension
 {
     public function getFilters()
     {
-        return array('nl2br' => new Twig_Filter_Method($this, 'nl2br', array('needs_environment' => true, 'is_safe' => array('html'))));
+        return array(
+            'escape_and_nl2br' => new Twig_Filter_Method($this, 'escape_and_nl2br', array('needs_environment' => true, 'is_safe' => array('html'))),
+            'nl2br' => new Twig_Filter_Method($this, 'nl2br', array('pre_escape' => 'html', 'is_safe' => array('html'))),
+            'escape_something' => new Twig_Filter_Method($this, 'escape_something', array('is_safe' => array('something'))),
+        );
     }
 
-    public function nl2br($env, $value, $sep = '<br />')
+    /**
+     * nl2br which also escapes, for testing escaper filters
+     */
+    public function escape_and_nl2br($env, $value, $sep = '<br />')
     {
-        return str_replace("\n", $sep."\n", twig_escape_filter($env, $value, 'html'));
+        return $this->nl2br(twig_escape_filter($env, $value, 'html'), $sep);
+    }
+
+    /**
+     * nl2br only, for testing filters with pre_escape
+     */
+    public function nl2br($value, $sep = '<br />')
+    {
+        // not secure if $value contains html tags (not only entities)
+        // don't use
+        return str_replace("\n", "$sep\n", $value);
+    }
+
+    public function escape_something($value)
+    {
+        return strtoupper($value);
     }
 
     public function getName()