Update HTML Purifier to version 4.4.0.

61 files changed, 1029 insertions, 360 deletions

diff --git a/lib/htmlpurifier/library/HTMLPurifier.includes.php b/lib/htmlpurifier/library/HTMLPurifier.includes.php
index b9baf8f0a..0ceff6a92 100644
--- a/lib/htmlpurifier/library/HTMLPurifier.includes.php
+++ b/lib/htmlpurifier/library/HTMLPurifier.includes.php
@@ -7,7 +7,7 @@
  * primary concern and you are using an opcode cache. PLEASE DO NOT EDIT THIS
  * FILE, changes will be overwritten the next time the script is run.
  *
- * @version 4.3.0
+ * @version 4.4.0
  *
  * @warning
  *      You must *not* include any other HTML Purifier files before this file,
@@ -73,6 +73,7 @@ require 'HTMLPurifier/UnitConverter.php';
 require 'HTMLPurifier/VarParser.php';
 require 'HTMLPurifier/VarParserException.php';
 require 'HTMLPurifier/AttrDef/CSS.php';
+require 'HTMLPurifier/AttrDef/Clone.php';
 require 'HTMLPurifier/AttrDef/Enum.php';
 require 'HTMLPurifier/AttrDef/Integer.php';
 require 'HTMLPurifier/AttrDef/Lang.php';
@@ -90,6 +91,7 @@ require 'HTMLPurifier/AttrDef/CSS/DenyElementDecorator.php';
 require 'HTMLPurifier/AttrDef/CSS/Filter.php';
 require 'HTMLPurifier/AttrDef/CSS/Font.php';
 require 'HTMLPurifier/AttrDef/CSS/FontFamily.php';
+require 'HTMLPurifier/AttrDef/CSS/Ident.php';
 require 'HTMLPurifier/AttrDef/CSS/ImportantDecorator.php';
 require 'HTMLPurifier/AttrDef/CSS/Length.php';
 require 'HTMLPurifier/AttrDef/CSS/ListStyle.php';
@@ -130,10 +132,12 @@ require 'HTMLPurifier/AttrTransform/SafeEmbed.php';
 require 'HTMLPurifier/AttrTransform/SafeObject.php';
 require 'HTMLPurifier/AttrTransform/SafeParam.php';
 require 'HTMLPurifier/AttrTransform/ScriptRequired.php';
+require 'HTMLPurifier/AttrTransform/TargetBlank.php';
 require 'HTMLPurifier/AttrTransform/Textarea.php';
 require 'HTMLPurifier/ChildDef/Chameleon.php';
 require 'HTMLPurifier/ChildDef/Custom.php';
 require 'HTMLPurifier/ChildDef/Empty.php';
+require 'HTMLPurifier/ChildDef/List.php';
 require 'HTMLPurifier/ChildDef/Required.php';
 require 'HTMLPurifier/ChildDef/Optional.php';
 require 'HTMLPurifier/ChildDef/StrictBlockquote.php';
@@ -148,6 +152,7 @@ require 'HTMLPurifier/HTMLModule/CommonAttributes.php';
 require 'HTMLPurifier/HTMLModule/Edit.php';
 require 'HTMLPurifier/HTMLModule/Forms.php';
 require 'HTMLPurifier/HTMLModule/Hypertext.php';
+require 'HTMLPurifier/HTMLModule/Iframe.php';
 require 'HTMLPurifier/HTMLModule/Image.php';
 require 'HTMLPurifier/HTMLModule/Legacy.php';
 require 'HTMLPurifier/HTMLModule/List.php';
@@ -164,6 +169,7 @@ require 'HTMLPurifier/HTMLModule/Scripting.php';
 require 'HTMLPurifier/HTMLModule/StyleAttribute.php';
 require 'HTMLPurifier/HTMLModule/Tables.php';
 require 'HTMLPurifier/HTMLModule/Target.php';
+require 'HTMLPurifier/HTMLModule/TargetBlank.php';
 require 'HTMLPurifier/HTMLModule/Text.php';
 require 'HTMLPurifier/HTMLModule/Tidy.php';
 require 'HTMLPurifier/HTMLModule/XMLCommonAttributes.php';
@@ -202,6 +208,7 @@ require 'HTMLPurifier/URIFilter/DisableResources.php';
 require 'HTMLPurifier/URIFilter/HostBlacklist.php';
 require 'HTMLPurifier/URIFilter/MakeAbsolute.php';
 require 'HTMLPurifier/URIFilter/Munge.php';
+require 'HTMLPurifier/URIFilter/SafeIframe.php';
 require 'HTMLPurifier/URIScheme/data.php';
 require 'HTMLPurifier/URIScheme/file.php';
 require 'HTMLPurifier/URIScheme/ftp.php';
diff --git a/lib/htmlpurifier/library/HTMLPurifier.php b/lib/htmlpurifier/library/HTMLPurifier.php
index 914ba25ae..e599e1c0c 100644
--- a/lib/htmlpurifier/library/HTMLPurifier.php
+++ b/lib/htmlpurifier/library/HTMLPurifier.php
@@ -19,7 +19,7 @@
  */
 
 /*
-    HTML Purifier 4.3.0 - Standards Compliant HTML Filtering
+    HTML Purifier 4.4.0 - Standards Compliant HTML Filtering
     Copyright (C) 2006-2008 Edward Z. Yang
 
     This library is free software; you can redistribute it and/or
@@ -55,10 +55,10 @@ class HTMLPurifier
 {
 
     /** Version of HTML Purifier */
-    public $version = '4.3.0';
+    public $version = '4.4.0';
 
     /** Constant with version of HTML Purifier */
-    const VERSION = '4.3.0';
+    const VERSION = '4.4.0';
 
     /** Global configuration object */
     public $config;
diff --git a/lib/htmlpurifier/library/HTMLPurifier.safe-includes.php b/lib/htmlpurifier/library/HTMLPurifier.safe-includes.php
index a5c0d5bb8..d49b196c4 100644
--- a/lib/htmlpurifier/library/HTMLPurifier.safe-includes.php
+++ b/lib/htmlpurifier/library/HTMLPurifier.safe-includes.php
@@ -67,6 +67,7 @@ require_once $__dir . '/HTMLPurifier/UnitConverter.php';
 require_once $__dir . '/HTMLPurifier/VarParser.php';
 require_once $__dir . '/HTMLPurifier/VarParserException.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS.php';
+require_once $__dir . '/HTMLPurifier/AttrDef/Clone.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/Enum.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/Integer.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/Lang.php';
@@ -84,6 +85,7 @@ require_once $__dir . '/HTMLPurifier/AttrDef/CSS/DenyElementDecorator.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS/Filter.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS/Font.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS/FontFamily.php';
+require_once $__dir . '/HTMLPurifier/AttrDef/CSS/Ident.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS/ImportantDecorator.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS/Length.php';
 require_once $__dir . '/HTMLPurifier/AttrDef/CSS/ListStyle.php';
@@ -124,10 +126,12 @@ require_once $__dir . '/HTMLPurifier/AttrTransform/SafeEmbed.php';
 require_once $__dir . '/HTMLPurifier/AttrTransform/SafeObject.php';
 require_once $__dir . '/HTMLPurifier/AttrTransform/SafeParam.php';
 require_once $__dir . '/HTMLPurifier/AttrTransform/ScriptRequired.php';
+require_once $__dir . '/HTMLPurifier/AttrTransform/TargetBlank.php';
 require_once $__dir . '/HTMLPurifier/AttrTransform/Textarea.php';
 require_once $__dir . '/HTMLPurifier/ChildDef/Chameleon.php';
 require_once $__dir . '/HTMLPurifier/ChildDef/Custom.php';
 require_once $__dir . '/HTMLPurifier/ChildDef/Empty.php';
+require_once $__dir . '/HTMLPurifier/ChildDef/List.php';
 require_once $__dir . '/HTMLPurifier/ChildDef/Required.php';
 require_once $__dir . '/HTMLPurifier/ChildDef/Optional.php';
 require_once $__dir . '/HTMLPurifier/ChildDef/StrictBlockquote.php';
@@ -142,6 +146,7 @@ require_once $__dir . '/HTMLPurifier/HTMLModule/CommonAttributes.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Edit.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Forms.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Hypertext.php';
+require_once $__dir . '/HTMLPurifier/HTMLModule/Iframe.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Image.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Legacy.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/List.php';
@@ -158,6 +163,7 @@ require_once $__dir . '/HTMLPurifier/HTMLModule/Scripting.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/StyleAttribute.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Tables.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Target.php';
+require_once $__dir . '/HTMLPurifier/HTMLModule/TargetBlank.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Text.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/Tidy.php';
 require_once $__dir . '/HTMLPurifier/HTMLModule/XMLCommonAttributes.php';
@@ -196,6 +202,7 @@ require_once $__dir . '/HTMLPurifier/URIFilter/DisableResources.php';
 require_once $__dir . '/HTMLPurifier/URIFilter/HostBlacklist.php';
 require_once $__dir . '/HTMLPurifier/URIFilter/MakeAbsolute.php';
 require_once $__dir . '/HTMLPurifier/URIFilter/Munge.php';
+require_once $__dir . '/HTMLPurifier/URIFilter/SafeIframe.php';
 require_once $__dir . '/HTMLPurifier/URIScheme/data.php';
 require_once $__dir . '/HTMLPurifier/URIScheme/file.php';
 require_once $__dir . '/HTMLPurifier/URIScheme/ftp.php';
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/CSS/Ident.php b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/CSS/Ident.php
new file mode 100644
index 000000000..779794a0b
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/CSS/Ident.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * Validates based on {ident} CSS grammar production
+ */
+class HTMLPurifier_AttrDef_CSS_Ident extends HTMLPurifier_AttrDef
+{
+
+    public function validate($string, $config, $context) {
+
+        $string = trim($string);
+
+        // early abort: '' and '0' (strings that convert to false) are invalid
+        if (!$string) return false;
+
+        $pattern = '/^(-?[A-Za-z_][A-Za-z_\-0-9]*)$/';
+        if (!preg_match($pattern, $string)) return false;
+        return $string;
+
+    }
+
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/Clone.php b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/Clone.php
new file mode 100644
index 000000000..ce68dbd54
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/Clone.php
@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * Dummy AttrDef that mimics another AttrDef, BUT it generates clones
+ * with make.
+ */
+class HTMLPurifier_AttrDef_Clone extends HTMLPurifier_AttrDef
+{
+    /**
+     * What we're cloning
+     */
+    protected $clone;
+
+    public function __construct($clone) {
+        $this->clone = $clone;
+    }
+
+    public function validate($v, $config, $context) {
+        return $this->clone->validate($v, $config, $context);
+    }
+
+    public function make($string) {
+        return clone $this->clone;
+    }
+
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/Color.php b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/Color.php
index d01e20454..00d865723 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/Color.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/Color.php
@@ -14,7 +14,7 @@ class HTMLPurifier_AttrDef_HTML_Color extends HTMLPurifier_AttrDef
         $string = trim($string);
 
         if (empty($string)) return false;
-        if (isset($colors[$string])) return $colors[$string];
+        if (isset($colors[strtolower($string)])) return $colors[$string];
         if ($string[0] === '#') $hex = substr($string, 1);
         else $hex = $string;
 
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/ID.php b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/ID.php
index 81d03762d..0015fa1eb 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/ID.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/HTML/ID.php
@@ -12,12 +12,22 @@
 class HTMLPurifier_AttrDef_HTML_ID extends HTMLPurifier_AttrDef
 {
 
-    // ref functionality disabled, since we also have to verify
-    // whether or not the ID it refers to exists
+    // selector is NOT a valid thing to use for IDREFs, because IDREFs
+    // *must* target IDs that exist, whereas selector #ids do not.
+
+    /**
+     * Determines whether or not we're validating an ID in a CSS
+     * selector context.
+     */
+    protected $selector;
+
+    public function __construct($selector = false) {
+        $this->selector = $selector;
+    }
 
     public function validate($id, $config, $context) {
 
-        if (!$config->get('Attr.EnableID')) return false;
+        if (!$this->selector && !$config->get('Attr.EnableID')) return false;
 
         $id = trim($id); // trim it first
 
@@ -33,10 +43,10 @@ class HTMLPurifier_AttrDef_HTML_ID extends HTMLPurifier_AttrDef
                 '%Attr.IDPrefix is set', E_USER_WARNING);
         }
 
-        //if (!$this->ref) {
+        if (!$this->selector) {
             $id_accumulator =& $context->get('IDAccumulator');
             if (isset($id_accumulator->ids[$id])) return false;
-        //}
+        }
 
         // we purposely avoid using regex, hopefully this is faster
 
@@ -56,7 +66,7 @@ class HTMLPurifier_AttrDef_HTML_ID extends HTMLPurifier_AttrDef
             return false;
         }
 
-        if (/*!$this->ref && */$result) $id_accumulator->add($id);
+        if (!$this->selector && $result) $id_accumulator->add($id);
 
         // if no change was made to the ID, return the result
         // else, return the new id if stripping whitespace made it
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI.php b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI.php
index 01a6d83e9..c2b684671 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI.php
@@ -19,7 +19,7 @@ class HTMLPurifier_AttrDef_URI extends HTMLPurifier_AttrDef
     }
 
     public function make($string) {
-        $embeds = (bool) $string;
+        $embeds = ($string === 'embedded');
         return new HTMLPurifier_AttrDef_URI($embeds);
     }
 
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI/Host.php b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI/Host.php
index feca469d7..125decb2d 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI/Host.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrDef/URI/Host.php
@@ -44,9 +44,8 @@ class HTMLPurifier_AttrDef_URI_Host extends HTMLPurifier_AttrDef
 
         // A regular domain name.
 
-        // This breaks I18N domain names, but we don't have proper IRI support,
-        // so force users to insert Punycode. If there's complaining we'll
-        // try to fix things into an international friendly form.
+        // This doesn't match I18N domain names, but we don't have proper IRI support,
+        // so force users to insert Punycode.
 
         // The productions describing this are:
         $a   = '[a-z]';     // alpha
@@ -57,10 +56,44 @@ class HTMLPurifier_AttrDef_URI_Host extends HTMLPurifier_AttrDef
         // toplabel    = alpha | alpha *( alphanum | "-" ) alphanum
         $toplabel      = "$a($and*$an)?";
         // hostname    = *( domainlabel "." ) toplabel [ "." ]
-        $match = preg_match("/^($domainlabel\.)*$toplabel\.?$/i", $string);
-        if (!$match) return false;
+        if (preg_match("/^($domainlabel\.)*$toplabel\.?$/i", $string)) {
+            return $string;
+        }
+
+        // If we have Net_IDNA2 support, we can support IRIs by
+        // punycoding them. (This is the most portable thing to do,
+        // since otherwise we have to assume browsers support
+
+        if ($config->get('Core.EnableIDNA')) {
+            $idna = new Net_IDNA2(array('encoding' => 'utf8', 'overlong' => false, 'strict' => true));
+            // we need to encode each period separately
+            $parts = explode('.', $string);
+            try {
+                $new_parts = array();
+                foreach ($parts as $part) {
+                    $encodable = false;
+                    for ($i = 0, $c = strlen($part); $i < $c; $i++) {
+                        if (ord($part[$i]) > 0x7a) {
+                            $encodable = true;
+                            break;
+                        }
+                    }
+                    if (!$encodable) {
+                        $new_parts[] = $part;
+                    } else {
+                        $new_parts[] = $idna->encode($part);
+                    }
+                }
+                $string = implode('.', $new_parts);
+                if (preg_match("/^($domainlabel\.)*$toplabel\.?$/i", $string)) {
+                    return $string;
+                }
+            } catch (Exception $e) {
+                // XXX error reporting
+            }
+        }
 
-        return $string;
+        return false;
     }
 
 }
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/Nofollow.php b/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/Nofollow.php
index 573b42c9c..f7fb1209b 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/Nofollow.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/Nofollow.php
@@ -24,9 +24,13 @@ class HTMLPurifier_AttrTransform_Nofollow extends HTMLPurifier_AttrTransform
         $url = $this->parser->parse($attr['href']);
         $scheme = $url->getSchemeObj($config, $context);
 
-        if (!is_null($url->host) && $scheme !== false && $scheme->browsable) {
+        if ($scheme->browsable && !$url->isLocal($config, $context)) {
             if (isset($attr['rel'])) {
-                $attr['rel'] .= ' nofollow';
+                $rels = explode(' ', $attr);
+                if (!in_array('nofollow', $rels)) {
+                    $rels[] = 'nofollow';
+                }
+                $attr['rel'] = implode(' ', $rels);
             } else {
                 $attr['rel'] = 'nofollow';
             }
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/TargetBlank.php b/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/TargetBlank.php
new file mode 100644
index 000000000..a6502c749
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/TargetBlank.php
@@ -0,0 +1,38 @@
+<?php
+
+// must be called POST validation
+
+/**
+ * Adds target="blank" to all outbound links.  This transform is
+ * only attached if Attr.TargetBlank is TRUE.  This works regardless
+ * of whether or not Attr.AllowedFrameTargets
+ */
+class HTMLPurifier_AttrTransform_TargetBlank extends HTMLPurifier_AttrTransform
+{
+    private $parser;
+
+    public function __construct() {
+        $this->parser = new HTMLPurifier_URIParser();
+    }
+
+    public function transform($attr, $config, $context) {
+
+        if (!isset($attr['href'])) {
+            return $attr;
+        }
+
+        // XXX Kind of inefficient
+        $url = $this->parser->parse($attr['href']);
+        $scheme = $url->getSchemeObj($config, $context);
+
+        if ($scheme->browsable && !$url->isBenign($config, $context)) {
+            $attr['target'] = 'blank';
+        }
+
+        return $attr;
+
+    }
+
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrTypes.php b/lib/htmlpurifier/library/HTMLPurifier/AttrTypes.php
index fc2ea4e58..6f985ff93 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/AttrTypes.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrTypes.php
@@ -15,6 +15,13 @@ class HTMLPurifier_AttrTypes
      * types.
      */
     public function __construct() {
+        // XXX This is kind of poor, since we don't actually /clone/
+        // instances; instead, we use the supplied make() attribute. So,
+        // the underlying class must know how to deal with arguments.
+        // With the old implementation of Enum, that ignored its
+        // arguments when handling a make dispatch, the IAlign
+        // definition wouldn't work.
+
         // pseudo-types, must be instantiated via shorthand
         $this->info['Enum']    = new HTMLPurifier_AttrDef_Enum();
         $this->info['Bool']    = new HTMLPurifier_AttrDef_HTML_Bool();
@@ -29,6 +36,9 @@ class HTMLPurifier_AttrTypes
         $this->info['URI']      = new HTMLPurifier_AttrDef_URI();
         $this->info['LanguageCode'] = new HTMLPurifier_AttrDef_Lang();
         $this->info['Color']    = new HTMLPurifier_AttrDef_HTML_Color();
+        $this->info['IAlign']   = self::makeEnum('top,middle,bottom,left,right');
+        $this->info['LAlign']   = self::makeEnum('top,bottom,left,right');
+        $this->info['FrameTarget'] = new HTMLPurifier_AttrDef_HTML_FrameTarget();
 
         // unimplemented aliases
         $this->info['ContentType'] = new HTMLPurifier_AttrDef_Text();
@@ -44,6 +54,10 @@ class HTMLPurifier_AttrTypes
         $this->info['Number']   = new HTMLPurifier_AttrDef_Integer(false, false, true);
     }
 
+    private static function makeEnum($in) {
+        return new HTMLPurifier_AttrDef_Clone(new HTMLPurifier_AttrDef_Enum(explode(',', $in)));
+    }
+
     /**
      * Retrieves a type
      * @param $type String type name
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ChildDef/List.php b/lib/htmlpurifier/library/HTMLPurifier/ChildDef/List.php
new file mode 100644
index 000000000..cdaa2893a
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ChildDef/List.php
@@ -0,0 +1,120 @@
+<?php
+
+/**
+ * Definition for list containers ul and ol.
+ */
+class HTMLPurifier_ChildDef_List extends HTMLPurifier_ChildDef
+{
+    public $type = 'list';
+    // lying a little bit, so that we can handle ul and ol ourselves
+    // XXX: This whole business with 'wrap' is all a bit unsatisfactory
+    public $elements = array('li' => true, 'ul' => true, 'ol' => true);
+    public function validateChildren($tokens_of_children, $config, $context) {
+        // Flag for subclasses
+        $this->whitespace = false;
+
+        // if there are no tokens, delete parent node
+        if (empty($tokens_of_children)) return false;
+
+        // the new set of children
+        $result = array();
+
+        // current depth into the nest
+        $nesting = 0;
+
+        // a little sanity check to make sure it's not ALL whitespace
+        $all_whitespace = true;
+
+        $seen_li = false;
+        $need_close_li = false;
+
+        foreach ($tokens_of_children as $token) {
+            if (!empty($token->is_whitespace)) {
+                $result[] = $token;
+                continue;
+            }
+            $all_whitespace = false; // phew, we're not talking about whitespace
+
+            if ($nesting == 1 && $need_close_li) {
+                $result[] = new HTMLPurifier_Token_End('li');
+                $nesting--;
+                $need_close_li = false;
+            }
+
+            $is_child = ($nesting == 0);
+
+            if ($token instanceof HTMLPurifier_Token_Start) {
+                $nesting++;
+            } elseif ($token instanceof HTMLPurifier_Token_End) {
+                $nesting--;
+            }
+
+            if ($is_child) {
+                if ($token->name === 'li') {
+                    // good
+                    $seen_li = true;
+                } elseif ($token->name === 'ul' || $token->name === 'ol') {
+                    // we want to tuck this into the previous li
+                    $need_close_li = true;
+                    $nesting++;
+                    if (!$seen_li) {
+                        // create a new li element
+                        $result[] = new HTMLPurifier_Token_Start('li');
+                    } else {
+                        // backtrack until </li> found
+                        while(true) {
+                            $t = array_pop($result);
+                            if ($t instanceof HTMLPurifier_Token_End) {
+                                // XXX actually, these invariants could very plausibly be violated
+                                // if we are doing silly things with modifying the set of allowed elements.
+                                // FORTUNATELY, it doesn't make a difference, since the allowed
+                                // elements are hard-coded here!
+                                if ($t->name !== 'li') {
+                                    trigger_error("Only li present invariant violated in List ChildDef", E_USER_ERROR);
+                                    return false;
+                                }
+                                break;
+                            } elseif ($t instanceof HTMLPurifier_Token_Empty) { // bleagh
+                                if ($t->name !== 'li') {
+                                    trigger_error("Only li present invariant violated in List ChildDef", E_USER_ERROR);
+                                    return false;
+                                }
+                                // XXX this should have a helper for it...
+                                $result[] = new HTMLPurifier_Token_Start('li', $t->attr, $t->line, $t->col, $t->armor);
+                                break;
+                            } else {
+                                if (!$t->is_whitespace) {
+                                    trigger_error("Only whitespace present invariant violated in List ChildDef", E_USER_ERROR);
+                                    return false;
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    // start wrapping (this doesn't precisely mimic
+                    // browser behavior, but what browsers do is kind of
+                    // hard to mimic in a standards compliant way
+                    // XXX Actually, this has no impact in practice,
+                    // because this gets handled earlier. Arguably,
+                    // we should rip out all of that processing
+                    $result[] = new HTMLPurifier_Token_Start('li');
+                    $nesting++;
+                    $seen_li = true;
+                    $need_close_li = true;
+                }
+            }
+            $result[] = $token;
+        }
+        if ($need_close_li) {
+            $result[] = new HTMLPurifier_Token_End('li');
+        }
+        if (empty($result)) return false;
+        if ($all_whitespace) {
+            return false;
+        }
+        if ($tokens_of_children == $result) return true;
+        return $result;
+    }
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ChildDef/Table.php b/lib/htmlpurifier/library/HTMLPurifier/ChildDef/Table.php
index 34f0227dd..9a93421a1 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/ChildDef/Table.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/ChildDef/Table.php
@@ -1,7 +1,33 @@
 <?php
 
 /**
- * Definition for tables
+ * Definition for tables.  The general idea is to extract out all of the
+ * essential bits, and then reconstruct it later.
+ *
+ * This is a bit confusing, because the DTDs and the W3C
+ * validators seem to disagree on the appropriate definition. The
+ * DTD claims:
+ *
+ *      (CAPTION?, (COL*|COLGROUP*), THEAD?, TFOOT?, TBODY+)
+ *
+ * But actually, the HTML4 spec then has this to say:
+ *
+ *      The TBODY start tag is always required except when the table
+ *      contains only one table body and no table head or foot sections.
+ *      The TBODY end tag may always be safely omitted.
+ *
+ * So the DTD is kind of wrong.  The validator is, unfortunately, kind
+ * of on crack.
+ *
+ * The definition changed again in XHTML1.1; and in my opinion, this
+ * formulation makes the most sense.
+ *
+ *      caption?, ( col* | colgroup* ), (( thead?, tfoot?, tbody+ ) | ( tr+ ))
+ *
+ * Essentially, we have two modes: thead/tfoot/tbody mode, and tr mode.
+ * If we encounter a thead, tfoot or tbody, we are placed in the former
+ * mode, and we *must* wrap any stray tr segments with a tbody. But if
+ * we don't run into any of them, just have tr tags is OK.
  */
 class HTMLPurifier_ChildDef_Table extends HTMLPurifier_ChildDef
 {
@@ -33,6 +59,8 @@ class HTMLPurifier_ChildDef_Table extends HTMLPurifier_ChildDef
         $collection = array(); // collected nodes
         $tag_index = 0; // the first node might be whitespace,
                             // so this tells us where the start tag is
+        $tbody_mode = false; // if true, then we need to wrap any stray
+                             // <tr>s with a <tbody>.
 
         foreach ($tokens_of_children as $token) {
             $is_child = ($nesting == 0);
@@ -51,8 +79,9 @@ class HTMLPurifier_ChildDef_Table extends HTMLPurifier_ChildDef
                     // okay, let's stash the tokens away
                     // first token tells us the type of the collection
                     switch ($collection[$tag_index]->name) {
-                        case 'tr':
                         case 'tbody':
+                            $tbody_mode = true;
+                        case 'tr':
                             $content[] = $collection;
                             break;
                         case 'caption':
@@ -61,13 +90,28 @@ class HTMLPurifier_ChildDef_Table extends HTMLPurifier_ChildDef
                             break;
                         case 'thead':
                         case 'tfoot':
+                            $tbody_mode = true;
+                            // XXX This breaks rendering properties with
+                            // Firefox, which never floats a <thead> to
+                            // the top. Ever. (Our scheme will float the
+                            // first <thead> to the top.)  So maybe
+                            // <thead>s that are not first should be
+                            // turned into <tbody>? Very tricky, indeed.
+
                             // access the appropriate variable, $thead or $tfoot
                             $var = $collection[$tag_index]->name;
                             if ($$var === false) {
                                 $$var = $collection;
                             } else {
-                                // transmutate the first and less entries into
-                                // tbody tags, and then put into content
+                                // Oops, there's a second one! What
+                                // should we do?  Current behavior is to
+                                // transmutate the first and last entries into
+                                // tbody tags, and then put into content.
+                                // Maybe a better idea is to *attach
+                                // it* to the existing thead or tfoot?
+                                // We don't do this, because Firefox
+                                // doesn't float an extra tfoot to the
+                                // bottom like it does for the first one.
                                 $collection[$tag_index]->name = 'tbody';
                                 $collection[count($collection)-1]->name = 'tbody';
                                 $content[] = $collection;
@@ -126,7 +170,48 @@ class HTMLPurifier_ChildDef_Table extends HTMLPurifier_ChildDef
         if ($cols !== false)    foreach ($cols as $token_array) $ret = array_merge($ret, $token_array);
         if ($thead !== false)   $ret = array_merge($ret, $thead);
         if ($tfoot !== false)   $ret = array_merge($ret, $tfoot);
-        foreach ($content as $token_array) $ret = array_merge($ret, $token_array);
+
+        if ($tbody_mode) {
+            // a little tricky, since the start of the collection may be
+            // whitespace
+            $inside_tbody = false;
+            foreach ($content as $token_array) {
+                // find the starting token
+                foreach ($token_array as $t) {
+                    if ($t->name === 'tr' || $t->name === 'tbody') {
+                        break;
+                    }
+                } // iterator variable carries over
+                if ($t->name === 'tr') {
+                    if ($inside_tbody) {
+                        $ret = array_merge($ret, $token_array);
+                    } else {
+                        $ret[] = new HTMLPurifier_Token_Start('tbody');
+                        $ret = array_merge($ret, $token_array);
+                        $inside_tbody = true;
+                    }
+                } elseif ($t->name === 'tbody') {
+                    if ($inside_tbody) {
+                        $ret[] = new HTMLPurifier_Token_End('tbody');
+                        $inside_tbody = false;
+                        $ret = array_merge($ret, $token_array);
+                    } else {
+                        $ret = array_merge($ret, $token_array);
+                    }
+                } else {
+                    trigger_error("tr/tbody in content invariant failed in Table ChildDef", E_USER_ERROR);
+                }
+            }
+            if ($inside_tbody) {
+                $ret[] = new HTMLPurifier_Token_End('tbody');
+            }
+        } else {
+            foreach ($content as $token_array) {
+                // invariant: everything in here is <tr>s
+                $ret = array_merge($ret, $token_array);
+            }
+        }
+
         if (!empty($collection) && $is_collecting == false){
             // grab the trailing space
             $ret = array_merge($ret, $collection);
diff --git a/lib/htmlpurifier/library/HTMLPurifier/Config.php b/lib/htmlpurifier/library/HTMLPurifier/Config.php
index b6551398f..554980f22 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/Config.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/Config.php
@@ -20,7 +20,7 @@ class HTMLPurifier_Config
     /**
      * HTML Purifier's version
      */
-    public $version = '4.3.0';
+    public $version = '4.4.0';
 
     /**
      * Bool indicator whether or not to automatically finalize
@@ -44,7 +44,7 @@ class HTMLPurifier_Config
     /**
      * Parser for variables
      */
-    protected $parser;
+    protected $parser = null;
 
     /**
      * Reference HTMLPurifier_ConfigSchema for value checking
@@ -668,7 +668,7 @@ class HTMLPurifier_Config
      */
     public function finalize() {
         $this->finalized = true;
-        unset($this->parser);
+        $this->parser = null;
     }
 
     /**
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/Interchange/Namespace.php b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/Interchange/Namespace.php
deleted file mode 100755
index 3ffac0a0f..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/Interchange/Namespace.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-
-/**
- * Interchange component class describing namespaces.
- */
-class HTMLPurifier_ConfigSchema_Interchange_Namespace
-{
-
-    /**
-     * Name of namespace defined.
-     */
-    public $namespace;
-
-    /**
-     * HTML description.
-     */
-    public $description;
-
-}
-
-// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema.ser b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema.ser
index 245ba5d2d..b106bcf79 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema.ser
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema.ser
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Attr.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Attr.txt
deleted file mode 100755
index 2d72049d6..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Attr.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Attr
-DESCRIPTION: Features regarding attribute validation.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormat.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormat.txt
deleted file mode 100755
index 161a52ef4..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormat.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-AutoFormat
-DESCRIPTION: Configuration for activating auto-formatting functionality (also known as <code>Injector</code>s)
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormatParam.PurifierLinkifyDocURL.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormatParam.PurifierLinkifyDocURL.txt
deleted file mode 100755
index 3e8309e39..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormatParam.PurifierLinkifyDocURL.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-AutoFormatParam.PurifierLinkifyDocURL
-TYPE: string
-VERSION: 2.0.1
-DEFAULT: '#%s'
---DESCRIPTION--
-
-<p>
-  Location of configuration documentation to link to, let %s substitute
-  into the configuration's namespace and directive names sans the percent
-  sign.
-</p>
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormatParam.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormatParam.txt
deleted file mode 100755
index 6097a557e..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/AutoFormatParam.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-AutoFormatParam
-DESCRIPTION: Configuration for customizing auto-formatting functionality
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/CSS.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/CSS.txt
deleted file mode 100755
index d14b49093..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/CSS.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-CSS
-DESCRIPTION: Configuration regarding allowed CSS.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Cache.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Cache.txt
deleted file mode 100755
index 57f30239a..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Cache.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Cache
-DESCRIPTION: Configuration for DefinitionCache and related subclasses.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.ColorKeywords.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.ColorKeywords.txt
index 08b381d34..c572c14ec 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.ColorKeywords.txt
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.ColorKeywords.txt
@@ -24,5 +24,6 @@ array (
 --DESCRIPTION--
 
 Lookup array of color names to six digit hexadecimal number corresponding
-to color, with preceding hash mark. Used when parsing colors.
+to color, with preceding hash mark. Used when parsing colors.  The lookup
+is done in a case-insensitive manner.
 --# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.EnableIDNA.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.EnableIDNA.txt
new file mode 100644
index 000000000..ce243c35d
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.EnableIDNA.txt
@@ -0,0 +1,9 @@
+Core.EnableIDNA
+TYPE: bool
+DEFAULT: false
+VERSION: 4.4.0
+--DESCRIPTION--
+Allows international domain names in URLs.  This configuration option
+requires the PEAR Net_IDNA2 module to be installed.  It operates by
+punycoding any internationalized host names for maximum portability.
+--# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.txt
deleted file mode 100755
index 5edfe0786..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Core.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Core
-DESCRIPTION: Core features that are always available.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Filter.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Filter.txt
deleted file mode 100755
index f2d25a1b2..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Filter.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Filter
-DESCRIPTION: Directives for turning filters on and off, or specifying custom filters.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksEscaping.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksEscaping.txt
deleted file mode 100755
index d436ed015..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksEscaping.txt
+++ /dev/null
@@ -1,14 +0,0 @@
-FilterParam.ExtractStyleBlocksEscaping
-TYPE: bool
-VERSION: 3.0.0
-DEFAULT: true
-ALIASES: Filter.ExtractStyleBlocksEscaping
---DESCRIPTION--
-
-<p>
-  Whether or not to escape the dangerous characters &lt;, &gt; and &amp;
-  as \3C, \3E and \26, respectively. This is can be safely set to false
-  if the contents of StyleBlocks will be placed in an external stylesheet,
-  where there is no risk of it being interpreted as HTML.
-</p>
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksScope.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksScope.txt
deleted file mode 100755
index 3943529c7..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksScope.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-FilterParam.ExtractStyleBlocksScope
-TYPE: string/null
-VERSION: 3.0.0
-DEFAULT: NULL
-ALIASES: Filter.ExtractStyleBlocksScope
---DESCRIPTION--
-
-<p>
-  If you would like users to be able to define external stylesheets, but
-  only allow them to specify CSS declarations for a specific node and
-  prevent them from fiddling with other elements, use this directive.
-  It accepts any valid CSS selector, and will prepend this to any
-  CSS declaration extracted from the document. For example, if this
-  directive is set to <code>#user-content</code> and a user uses the
-  selector <code>a:hover</code>, the final selector will be
-  <code>#user-content a:hover</code>.
-</p>
-<p>
-  The comma shorthand may be used; consider the above example, with
-  <code>#user-content, #user-content2</code>, the final selector will
-  be <code>#user-content a:hover, #user-content2 a:hover</code>.
-</p>
-<p>
-  <strong>Warning:</strong> It is possible for users to bypass this measure
-  using a naughty + selector. This is a bug in CSS Tidy 1.3, not HTML
-  Purifier, and I am working to get it fixed. Until then, HTML Purifier
-  performs a basic check to prevent this.
-</p>
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksTidyImpl.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksTidyImpl.txt
deleted file mode 100755
index cafccf8b5..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.ExtractStyleBlocksTidyImpl.txt
+++ /dev/null
@@ -1,15 +0,0 @@
-FilterParam.ExtractStyleBlocksTidyImpl
-TYPE: mixed/null
-VERSION: 3.1.0
-DEFAULT: NULL
---DESCRIPTION--
-<p>
-  If left NULL, HTML Purifier will attempt to instantiate a <code>csstidy</code>
-  class to use for internal cleaning. This will usually be good enough.
-</p>
-<p>
-  However, for trusted user input, you can set this to <code>false</code> to
-  disable cleaning. In addition, you can supply your own concrete implementation
-  of Tidy's interface to use, although I don't know why you'd want to do that.
-</p>
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.txt
deleted file mode 100755
index dff9784b1..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/FilterParam.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-FilterParam
-DESCRIPTION: Configuration for filters.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.AllowedComments.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.AllowedComments.txt
new file mode 100644
index 000000000..140e21423
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.AllowedComments.txt
@@ -0,0 +1,10 @@
+HTML.AllowedComments
+TYPE: lookup
+VERSION: 4.4.0
+DEFAULT: array()
+--DESCRIPTION--
+A whitelist which indicates what explicit comment bodies should be
+allowed, modulo leading and trailing whitespace.  See also %HTML.AllowedCommentsRegexp
+(these directives are union'ed together, so a comment is considered
+valid if any directive deems it valid.)
+--# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.AllowedCommentsRegexp.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.AllowedCommentsRegexp.txt
new file mode 100644
index 000000000..f22e977d4
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.AllowedCommentsRegexp.txt
@@ -0,0 +1,15 @@
+HTML.AllowedCommentsRegexp
+TYPE: string/null
+VERSION: 4.4.0
+DEFAULT: NULL
+--DESCRIPTION--
+A regexp, which if it matches the body of a comment, indicates that
+it should be allowed. Trailing and leading spaces are removed prior
+to running this regular expression.
+<strong>Warning:</strong> Make sure you specify
+correct anchor metacharacters <code>^regex$</code>, otherwise you may accept
+comments that you did not mean to! In particular, the regex <code>/foo|bar/</code>
+is probably not sufficiently strict, since it also allows <code>foobar</code>.
+See also %HTML.AllowedComments (these directives are union'ed together,
+so a comment is considered valid if any directive deems it valid.)
+--# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.SafeIframe.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.SafeIframe.txt
new file mode 100644
index 000000000..5eb6ec2b5
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.SafeIframe.txt
@@ -0,0 +1,13 @@
+HTML.SafeIframe
+TYPE: bool
+VERSION: 4.4.0
+DEFAULT: false
+--DESCRIPTION--
+<p>
+    Whether or not to permit iframe tags in untrusted documents.  This
+    directive must be accompanied by a whitelist of permitted iframes,
+    such as %URI.SafeIframeRegexp, otherwise it will fatally error.
+    This directive has no effect on strict doctypes, as iframes are not
+    valid.
+</p>
+--# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.TargetBlank.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.TargetBlank.txt
new file mode 100644
index 000000000..587a16778
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.TargetBlank.txt
@@ -0,0 +1,8 @@
+HTML.TargetBlank
+TYPE: bool
+VERSION: 4.4.0
+DEFAULT: FALSE
+--DESCRIPTION--
+If enabled, <code>target=blank</code> attributes are added to all outgoing links.
+(This includes links from an HTTPS version of a page to an HTTP version.)
+--# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.txt
deleted file mode 100755
index f32ceb5b6..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/HTML.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-HTML
-DESCRIPTION: Configuration regarding allowed HTML.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Output.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Output.txt
deleted file mode 100755
index 7849d60d2..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Output.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Output
-DESCRIPTION: Configuration relating to the generation of (X)HTML.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Test.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Test.txt
deleted file mode 100755
index 5025f9d14..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/Test.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-Test
-DESCRIPTION: Developer testing configuration for our unit tests.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/URI.SafeIframeRegexp.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/URI.SafeIframeRegexp.txt
new file mode 100644
index 000000000..79084832b
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/URI.SafeIframeRegexp.txt
@@ -0,0 +1,22 @@
+URI.SafeIframeRegexp
+TYPE: string/null
+VERSION: 4.4.0
+DEFAULT: NULL
+--DESCRIPTION--
+<p>
+    A PCRE regular expression that will be matched against an iframe URI.  This is
+    a relatively inflexible scheme, but works well enough for the most common
+    use-case of iframes: embedded video.  This directive only has an effect if
+    %HTML.SafeIframe is enabled.  Here are some example values:
+</p>
+<ul>
+    <li><code>%^http://www.youtube.com/embed/%</code> - Allow YouTube videos</li>
+    <li><code>%^http://player.vimeo.com/video/%</code> - Allow Vimeo videos</li>
+    <li><code>%^http://(www.youtube.com/embed/|player.vimeo.com/video/)%</code> - Allow both</li>
+</ul>
+<p>
+    Note that this directive does not give you enough granularity to, say, disable
+    all <code>autoplay</code> videos.  Pipe up on the HTML Purifier forums if this
+    is a capability you want.
+</p>
+--# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/URI.txt b/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/URI.txt
deleted file mode 100755
index a13060f36..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/ConfigSchema/schema/URI.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-URI
-DESCRIPTION: Features regarding Uniform Resource Identifiers.
---# vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/Encoder.php b/lib/htmlpurifier/library/HTMLPurifier/Encoder.php
index 2b3140caa..9fa76bd18 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/Encoder.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/Encoder.php
@@ -20,6 +20,68 @@ class HTMLPurifier_Encoder
     public static function muteErrorHandler() {}
 
     /**
+     * iconv wrapper which mutes errors, but doesn't work around bugs.
+     */
+    public static function unsafeIconv($in, $out, $text) {
+        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
+        $r = iconv($in, $out, $text);
+        restore_error_handler();
+        return $r;
+    }
+
+    /**
+     * iconv wrapper which mutes errors and works around bugs.
+     */
+    public static function iconv($in, $out, $text, $max_chunk_size = 8000) {
+        $code = self::testIconvTruncateBug();
+        if ($code == self::ICONV_OK) {
+            return self::unsafeIconv($in, $out, $text);
+        } elseif ($code == self::ICONV_TRUNCATES) {
+            // we can only work around this if the input character set
+            // is utf-8
+            if ($in == 'utf-8') {
+                if ($max_chunk_size < 4) {
+                    trigger_error('max_chunk_size is too small', E_USER_WARNING);
+                    return false;
+                }
+                // split into 8000 byte chunks, but be careful to handle
+                // multibyte boundaries properly
+                if (($c = strlen($text)) <= $max_chunk_size) {
+                    return self::unsafeIconv($in, $out, $text);
+                }
+                $r = '';
+                $i = 0;
+                while (true) {
+                    if ($i + $max_chunk_size >= $c) {
+                        $r .= self::unsafeIconv($in, $out, substr($text, $i));
+                        break;
+                    }
+                    // wibble the boundary
+                    if (0x80 != (0xC0 & ord($text[$i + $max_chunk_size]))) {
+                        $chunk_size = $max_chunk_size;
+                    } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 1]))) {
+                        $chunk_size = $max_chunk_size - 1;
+                    } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 2]))) {
+                        $chunk_size = $max_chunk_size - 2;
+                    } elseif (0x80 != (0xC0 & ord($text[$i + $max_chunk_size - 3]))) {
+                        $chunk_size = $max_chunk_size - 3;
+                    } else {
+                        return false; // rather confusing UTF-8...
+                    }
+                    $chunk = substr($text, $i, $chunk_size); // substr doesn't mind overlong lengths
+                    $r .= self::unsafeIconv($in, $out, $chunk);
+                    $i += $chunk_size;
+                }
+                return $r;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+    /**
      * Cleans a UTF-8 string for well-formedness and SGML validity
      *
      * It will parse according to UTF-8 and return a valid UTF8 string, with
@@ -260,6 +322,14 @@ class HTMLPurifier_Encoder
         return $ret;
     }
 
+    public static function iconvAvailable() {
+        static $iconv = null;
+        if ($iconv === null) {
+            $iconv = function_exists('iconv') && self::testIconvTruncateBug() != self::ICONV_UNUSABLE;
+        }
+        return $iconv;
+    }
+
     /**
      * Converts a string to UTF-8 based on configuration.
      */
@@ -267,25 +337,22 @@ class HTMLPurifier_Encoder
         $encoding = $config->get('Core.Encoding');
         if ($encoding === 'utf-8') return $str;
         static $iconv = null;
-        if ($iconv === null) $iconv = function_exists('iconv');
-        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
+        if ($iconv === null) $iconv = self::iconvAvailable();
         if ($iconv && !$config->get('Test.ForceNoIconv')) {
-            $str = iconv($encoding, 'utf-8//IGNORE', $str);
+            // unaffected by bugs, since UTF-8 support all characters
+            $str = self::unsafeIconv($encoding, 'utf-8//IGNORE', $str);
             if ($str === false) {
                 // $encoding is not a valid encoding
-                restore_error_handler();
                 trigger_error('Invalid encoding ' . $encoding, E_USER_ERROR);
                 return '';
             }
             // If the string is bjorked by Shift_JIS or a similar encoding
             // that doesn't support all of ASCII, convert the naughty
             // characters to their true byte-wise ASCII/UTF-8 equivalents.
-            $str = strtr($str, HTMLPurifier_Encoder::testEncodingSupportsASCII($encoding));
-            restore_error_handler();
+            $str = strtr($str, self::testEncodingSupportsASCII($encoding));
             return $str;
         } elseif ($encoding === 'iso-8859-1') {
             $str = utf8_encode($str);
-            restore_error_handler();
             return $str;
         }
         trigger_error('Encoding not supported, please install iconv', E_USER_ERROR);
@@ -298,16 +365,15 @@ class HTMLPurifier_Encoder
      */
     public static function convertFromUTF8($str, $config, $context) {
         $encoding = $config->get('Core.Encoding');
-        if ($encoding === 'utf-8') return $str;
-        static $iconv = null;
-        if ($iconv === null) $iconv = function_exists('iconv');
         if ($escape = $config->get('Core.EscapeNonASCIICharacters')) {
-            $str = HTMLPurifier_Encoder::convertToASCIIDumbLossless($str);
+            $str = self::convertToASCIIDumbLossless($str);
         }
-        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
+        if ($encoding === 'utf-8') return $str;
+        static $iconv = null;
+        if ($iconv === null) $iconv = self::iconvAvailable();
         if ($iconv && !$config->get('Test.ForceNoIconv')) {
             // Undo our previous fix in convertToUTF8, otherwise iconv will barf
-            $ascii_fix = HTMLPurifier_Encoder::testEncodingSupportsASCII($encoding);
+            $ascii_fix = self::testEncodingSupportsASCII($encoding);
             if (!$escape && !empty($ascii_fix)) {
                 $clear_fix = array();
                 foreach ($ascii_fix as $utf8 => $native) $clear_fix[$utf8] = '';
@@ -315,15 +381,17 @@ class HTMLPurifier_Encoder
             }
             $str = strtr($str, array_flip($ascii_fix));
             // Normal stuff
-            $str = iconv('utf-8', $encoding . '//IGNORE', $str);
-            restore_error_handler();
+            $str = self::iconv('utf-8', $encoding . '//IGNORE', $str);
             return $str;
         } elseif ($encoding === 'iso-8859-1') {
             $str = utf8_decode($str);
-            restore_error_handler();
             return $str;
         }
         trigger_error('Encoding not supported', E_USER_ERROR);
+        // You might be tempted to assume that the ASCII representation
+        // might be OK, however, this is *not* universally true over all
+        // encodings.  So we take the conservative route here, rather
+        // than forcibly turn on %Core.EscapeNonASCIICharacters
     }
 
     /**
@@ -373,6 +441,49 @@ class HTMLPurifier_Encoder
         return $result;
     }
 
+    /** No bugs detected in iconv. */
+    const ICONV_OK = 0;
+
+    /** Iconv truncates output if converting from UTF-8 to another
+     *  character set with //IGNORE, and a non-encodable character is found */
+    const ICONV_TRUNCATES = 1;
+
+    /** Iconv does not support //IGNORE, making it unusable for
+     *  transcoding purposes */
+    const ICONV_UNUSABLE = 2;
+
+    /**
+     * glibc iconv has a known bug where it doesn't handle the magic
+     * //IGNORE stanza correctly.  In particular, rather than ignore
+     * characters, it will return an EILSEQ after consuming some number
+     * of characters, and expect you to restart iconv as if it were
+     * an E2BIG.  Old versions of PHP did not respect the errno, and
+     * returned the fragment, so as a result you would see iconv
+     * mysteriously truncating output. We can work around this by
+     * manually chopping our input into segments of about 8000
+     * characters, as long as PHP ignores the error code.  If PHP starts
+     * paying attention to the error code, iconv becomes unusable.
+     *
+     * @returns Error code indicating severity of bug.
+     */
+    public static function testIconvTruncateBug() {
+        static $code = null;
+        if ($code === null) {
+            // better not use iconv, otherwise infinite loop!
+            $r = self::unsafeIconv('utf-8', 'ascii//IGNORE', "\xCE\xB1" . str_repeat('a', 9000));
+            if ($r === false) {
+                $code = self::ICONV_UNUSABLE;
+            } elseif (($c = strlen($r)) < 9000) {
+                $code = self::ICONV_TRUNCATES;
+            } elseif ($c > 9000) {
+                trigger_error('Your copy of iconv is extremely buggy. Please notify HTML Purifier maintainers: include your iconv version as per phpversion()', E_USER_ERROR);
+            } else {
+                $code = self::ICONV_OK;
+            }
+        }
+        return $code;
+    }
+
     /**
      * This expensive function tests whether or not a given character
      * encoding supports ASCII. 7/8-bit encodings like Shift_JIS will
@@ -385,6 +496,11 @@ class HTMLPurifier_Encoder
      *      which can be used to "undo" any overzealous iconv action.
      */
     public static function testEncodingSupportsASCII($encoding, $bypass = false) {
+        // All calls to iconv here are unsafe, proof by case analysis:
+        // If ICONV_OK, no difference.
+        // If ICONV_TRUNCATE, all calls involve one character inputs,
+        // so bug is not triggered.
+        // If ICONV_UNUSABLE, this call is irrelevant
         static $encodings = array();
         if (!$bypass) {
             if (isset($encodings[$encoding])) return $encodings[$encoding];
@@ -398,24 +514,22 @@ class HTMLPurifier_Encoder
             if (strpos($lenc, 'iso-8859-') === 0) return array();
         }
         $ret = array();
-        set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler'));
-        if (iconv('UTF-8', $encoding, 'a') === false) return false;
+        if (self::unsafeIconv('UTF-8', $encoding, 'a') === false) return false;
         for ($i = 0x20; $i <= 0x7E; $i++) { // all printable ASCII chars
             $c = chr($i); // UTF-8 char
-            $r = iconv('UTF-8', "$encoding//IGNORE", $c); // initial conversion
+            $r = self::unsafeIconv('UTF-8', "$encoding//IGNORE", $c); // initial conversion
             if (
                 $r === '' ||
                 // This line is needed for iconv implementations that do not
                 // omit characters that do not exist in the target character set
-                ($r === $c && iconv($encoding, 'UTF-8//IGNORE', $r) !== $c)
+                ($r === $c && self::unsafeIconv($encoding, 'UTF-8//IGNORE', $r) !== $c)
             ) {
                 // Reverse engineer: what's the UTF-8 equiv of this byte
                 // sequence? This assumes that there's no variable width
                 // encoding that doesn't support ASCII.
-                $ret[iconv($encoding, 'UTF-8//IGNORE', $c)] = $c;
+                $ret[self::unsafeIconv($encoding, 'UTF-8//IGNORE', $c)] = $c;
             }
         }
-        restore_error_handler();
         $encodings[$encoding] = $ret;
         return $ret;
     }
diff --git a/lib/htmlpurifier/library/HTMLPurifier/Filter/ExtractStyleBlocks.php b/lib/htmlpurifier/library/HTMLPurifier/Filter/ExtractStyleBlocks.php
index bbf78a663..320aa4f16 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/Filter/ExtractStyleBlocks.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/Filter/ExtractStyleBlocks.php
@@ -1,5 +1,11 @@
 <?php
 
+// why is this a top level function? Because PHP 5.2.0 doesn't seem to
+// understand how to interpret this filter if it's a static method.
+// It's all really silly, but if we go this route it might be reasonable
+// to coalesce all of these methods into one.
+function htmlpurifier_filter_extractstyleblocks_muteerrorhandler() {}
+
 /**
  * This filter extracts <style> blocks from input HTML, cleans them up
  * using CSSTidy, and then places them in $purifier->context->get('StyleBlocks')
@@ -21,8 +27,15 @@ class HTMLPurifier_Filter_ExtractStyleBlocks extends HTMLPurifier_Filter
     private $_styleMatches = array();
     private $_tidy;
 
+    private $_id_attrdef;
+    private $_class_attrdef;
+    private $_enum_attrdef;
+
     public function __construct() {
         $this->_tidy = new csstidy();
+        $this->_id_attrdef = new HTMLPurifier_AttrDef_HTML_ID(true);
+        $this->_class_attrdef = new HTMLPurifier_AttrDef_CSS_Ident();
+        $this->_enum_attrdef = new HTMLPurifier_AttrDef_Enum(array('first-child', 'link', 'visited', 'active', 'hover', 'focus'));
     }
 
     /**
@@ -77,27 +90,166 @@ class HTMLPurifier_Filter_ExtractStyleBlocks extends HTMLPurifier_Filter
             $css = substr($css, 0, -3);
         }
         $css = trim($css);
+        set_error_handler('htmlpurifier_filter_extractstyleblocks_muteerrorhandler');
         $this->_tidy->parse($css);
+        restore_error_handler();
         $css_definition = $config->getDefinition('CSS');
+        $html_definition = $config->getDefinition('HTML');
+        $new_css = array();
         foreach ($this->_tidy->css as $k => $decls) {
             // $decls are all CSS declarations inside an @ selector
             $new_decls = array();
             foreach ($decls as $selector => $style) {
                 $selector = trim($selector);
                 if ($selector === '') continue; // should not happen
-                if ($selector[0] === '+') {
-                    if ($selector !== '' && $selector[0] === '+') continue;
-                }
-                if (!empty($scopes)) {
-                    $new_selector = array(); // because multiple ones are possible
-                    $selectors = array_map('trim', explode(',', $selector));
-                    foreach ($scopes as $s1) {
-                        foreach ($selectors as $s2) {
-                            $new_selector[] = "$s1 $s2";
+                // Parse the selector
+                // Here is the relevant part of the CSS grammar:
+                //
+                // ruleset
+                //   : selector [ ',' S* selector ]* '{' ...
+                // selector
+                //   : simple_selector [ combinator selector | S+ [ combinator? selector ]? ]?
+                // combinator
+                //   : '+' S*
+                //   : '>' S*
+                // simple_selector
+                //   : element_name [ HASH | class | attrib | pseudo ]*
+                //   | [ HASH | class | attrib | pseudo ]+
+                // element_name
+                //   : IDENT | '*'
+                //   ;
+                // class
+                //   : '.' IDENT
+                //   ;
+                // attrib
+                //   : '[' S* IDENT S* [ [ '=' | INCLUDES | DASHMATCH ] S*
+                //     [ IDENT | STRING ] S* ]? ']'
+                //   ;
+                // pseudo
+                //   : ':' [ IDENT | FUNCTION S* [IDENT S*]? ')' ]
+                //   ;
+                //
+                // For reference, here are the relevant tokens:
+                //
+                // HASH         #{name}
+                // IDENT        {ident}
+                // INCLUDES     ==
+                // DASHMATCH    |=
+                // STRING       {string}
+                // FUNCTION     {ident}\(
+                //
+                // And the lexical scanner tokens
+                //
+                // name         {nmchar}+
+                // nmchar       [_a-z0-9-]|{nonascii}|{escape}
+                // nonascii     [\240-\377]
+                // escape       {unicode}|\\[^\r\n\f0-9a-f]
+                // unicode      \\{h}}{1,6}(\r\n|[ \t\r\n\f])?
+                // ident        -?{nmstart}{nmchar*}
+                // nmstart      [_a-z]|{nonascii}|{escape}
+                // string       {string1}|{string2}
+                // string1      \"([^\n\r\f\\"]|\\{nl}|{escape})*\"
+                // string2      \'([^\n\r\f\\"]|\\{nl}|{escape})*\'
+                //
+                // We'll implement a subset (in order to reduce attack
+                // surface); in particular:
+                //
+                //      - No Unicode support
+                //      - No escapes support
+                //      - No string support (by proxy no attrib support)
+                //      - element_name is matched against allowed
+                //        elements (some people might find this
+                //        annoying...)
+                //      - Pseudo-elements one of :first-child, :link,
+                //        :visited, :active, :hover, :focus
+
+                // handle ruleset
+                $selectors = array_map('trim', explode(',', $selector));
+                $new_selectors = array();
+                foreach ($selectors as $sel) {
+                    // split on +, > and spaces
+                    $basic_selectors = preg_split('/\s*([+> ])\s*/', $sel, -1, PREG_SPLIT_DELIM_CAPTURE);
+                    // even indices are chunks, odd indices are
+                    // delimiters
+                    $nsel = null;
+                    $delim = null; // guaranteed to be non-null after
+                                   // two loop iterations
+                    for ($i = 0, $c = count($basic_selectors); $i < $c; $i++) {
+                        $x = $basic_selectors[$i];
+                        if ($i % 2) {
+                            // delimiter
+                            if ($x === ' ') {
+                                $delim = ' ';
+                            } else {
+                                $delim = ' ' . $x . ' ';
+                            }
+                        } else {
+                            // simple selector
+                            $components = preg_split('/([#.:])/', $x, -1, PREG_SPLIT_DELIM_CAPTURE);
+                            $sdelim = null;
+                            $nx = null;
+                            for ($j = 0, $cc = count($components); $j < $cc; $j ++) {
+                                $y = $components[$j];
+                                if ($j === 0) {
+                                    if ($y === '*' || isset($html_definition->info[$y = strtolower($y)])) {
+                                        $nx = $y;
+                                    } else {
+                                        // $nx stays null; this matters
+                                        // if we don't manage to find
+                                        // any valid selector content,
+                                        // in which case we ignore the
+                                        // outer $delim
+                                    }
+                                } elseif ($j % 2) {
+                                    // set delimiter
+                                    $sdelim = $y;
+                                } else {
+                                    $attrdef = null;
+                                    if ($sdelim === '#') {
+                                        $attrdef = $this->_id_attrdef;
+                                    } elseif ($sdelim === '.') {
+                                        $attrdef = $this->_class_attrdef;
+                                    } elseif ($sdelim === ':') {
+                                        $attrdef = $this->_enum_attrdef;
+                                    } else {
+                                        throw new HTMLPurifier_Exception('broken invariant sdelim and preg_split');
+                                    }
+                                    $r = $attrdef->validate($y, $config, $context);
+                                    if ($r !== false) {
+                                        if ($r !== true) {
+                                            $y = $r;
+                                        }
+                                        if ($nx === null) {
+                                            $nx = '';
+                                        }
+                                        $nx .= $sdelim . $y;
+                                    }
+                                }
+                            }
+                            if ($nx !== null) {
+                                if ($nsel === null) {
+                                    $nsel = $nx;
+                                } else {
+                                    $nsel .= $delim . $nx;
+                                }
+                            } else {
+                                // delimiters to the left of invalid
+                                // basic selector ignored
+                            }
+                        }
+                    }
+                    if ($nsel !== null) {
+                        if (!empty($scopes)) {
+                            foreach ($scopes as $s) {
+                                $new_selectors[] = "$s $nsel";
+                            }
+                        } else {
+                            $new_selectors[] = $nsel;
                         }
                     }
-                    $selector = implode(', ', $new_selector); // now it's a string
                 }
+                if (empty($new_selectors)) continue;
+                $selector = implode(', ', $new_selectors);
                 foreach ($style as $name => $value) {
                     if (!isset($css_definition->info[$name])) {
                         unset($style[$name]);
@@ -110,10 +262,11 @@ class HTMLPurifier_Filter_ExtractStyleBlocks extends HTMLPurifier_Filter
                 }
                 $new_decls[$selector] = $style;
             }
-            $this->_tidy->css[$k] = $new_decls;
+            $new_css[$k] = $new_decls;
         }
         // remove stuff that shouldn't be used, could be reenabled
         // after security risks are analyzed
+        $this->_tidy->css = $new_css;
         $this->_tidy->import = array();
         $this->_tidy->charset = null;
         $this->_tidy->namespace = null;
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLDefinition.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLDefinition.php
index 33bb38ac5..b079d44c1 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/HTMLDefinition.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLDefinition.php
@@ -147,7 +147,7 @@ class HTMLPurifier_HTMLDefinition extends HTMLPurifier_Definition
         return $this->_anonModule;
     }
 
-    private $_anonModule;
+    private $_anonModule = null;
 
 
     // PUBLIC BUT INTERNAL VARIABLES --------------------------------------
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Forms.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Forms.php
index 44c22f6f8..b963529a7 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Forms.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Forms.php
@@ -35,7 +35,7 @@ class HTMLPurifier_HTMLModule_Forms extends HTMLPurifier_HTMLModule
             'name' => 'CDATA',
             'readonly' => 'Bool#readonly',
             'size' => 'Number',
-            'src' => 'URI#embeds',
+            'src' => 'URI#embedded',
             'tabindex' => 'Number',
             'type' => 'Enum#text,password,checkbox,button,radio,submit,reset,file,hidden,image',
             'value' => 'CDATA',
@@ -84,7 +84,8 @@ class HTMLPurifier_HTMLModule_Forms extends HTMLPurifier_HTMLModule
         $button->excludes = $this->makeLookup(
             'form', 'fieldset', // Form
             'input', 'select', 'textarea', 'label', 'button', // Formctrl
-            'a' // as per HTML 4.01 spec, this is omitted by modularization
+            'a', // as per HTML 4.01 spec, this is omitted by modularization
+            'isindex', 'iframe' // legacy items
         );
 
         // Extra exclusion: img usemap="" is not permitted within this element.
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Iframe.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Iframe.php
new file mode 100644
index 000000000..287071edf
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Iframe.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * XHTML 1.1 Iframe Module provides inline frames.
+ *
+ * @note This module is not considered safe unless an Iframe
+ * whitelisting mechanism is specified.  Currently, the only
+ * such mechanism is %URL.SafeIframeRegexp
+ */
+class HTMLPurifier_HTMLModule_Iframe extends HTMLPurifier_HTMLModule
+{
+
+    public $name = 'Iframe';
+    public $safe = false;
+
+    public function setup($config) {
+        if ($config->get('HTML.SafeIframe')) {
+            $this->safe = true;
+        }
+        $this->addElement(
+            'iframe', 'Inline', 'Flow', 'Common',
+            array(
+                'src' => 'URI#embedded',
+                'width' => 'Length',
+                'height' => 'Length',
+                'name' => 'ID',
+                'scrolling' => 'Enum#yes,no,auto',
+                'frameborder' => 'Enum#0,1',
+                'longdesc' => 'URI',
+                'marginheight' => 'Pixels',
+                'marginwidth' => 'Pixels',
+            )
+        );
+    }
+
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Legacy.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Legacy.php
index df33927ba..f278eeced 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Legacy.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Legacy.php
@@ -89,7 +89,7 @@ class HTMLPurifier_HTMLModule_Legacy extends HTMLPurifier_HTMLModule
         $hr->attr['width'] = 'Length';
 
         $img = $this->addBlankElement('img');
-        $img->attr['align'] = 'Enum#top,middle,bottom,left,right';
+        $img->attr['align'] = 'IAlign';
         $img->attr['border'] = 'Pixels';
         $img->attr['hspace'] = 'Pixels';
         $img->attr['vspace'] = 'Pixels';
@@ -136,6 +136,22 @@ class HTMLPurifier_HTMLModule_Legacy extends HTMLPurifier_HTMLModule
         $ul->attr['compact'] = 'Bool#compact';
         $ul->attr['type'] = 'Enum#square,disc,circle';
 
+        // "safe" modifications to "unsafe" elements
+        // WARNING: If you want to add support for an unsafe, legacy
+        // attribute, make a new TrustedLegacy module with the trusted
+        // bit set appropriately
+
+        $form = $this->addBlankElement('form');
+        $form->content_model = 'Flow | #PCDATA';
+        $form->content_model_type = 'optional';
+        $form->attr['target'] = 'FrameTarget';
+
+        $input = $this->addBlankElement('input');
+        $input->attr['align'] = 'IAlign';
+
+        $legend = $this->addBlankElement('legend');
+        $legend->attr['align'] = 'LAlign';
+
     }
 
 }
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/List.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/List.php
index 74d4522f4..79ccefafd 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/List.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/List.php
@@ -20,10 +20,16 @@ class HTMLPurifier_HTMLModule_List extends HTMLPurifier_HTMLModule
     public $content_sets = array('Flow' => 'List');
 
     public function setup($config) {
-        $ol = $this->addElement('ol', 'List', 'Required: li', 'Common');
-        $ol->wrap = "li";
-        $ul = $this->addElement('ul', 'List', 'Required: li', 'Common');
-        $ul->wrap = "li";
+        $ol = $this->addElement('ol', 'List', new HTMLPurifier_ChildDef_List(), 'Common');
+        $ul = $this->addElement('ul', 'List', new HTMLPurifier_ChildDef_List(), 'Common');
+        // XXX The wrap attribute is handled by MakeWellFormed.  This is all
+        // quite unsatisfactory, because we generated this
+        // *specifically* for lists, and now a big chunk of the handling
+        // is done properly by the List ChildDef.  So actually, we just
+        // want enough information to make autoclosing work properly,
+        // and then hand off the tricky stuff to the ChildDef.
+        $ol->wrap = 'li';
+        $ul->wrap = 'li';
         $this->addElement('dl', 'List', 'Required: dt | dd', 'Common');
 
         $this->addElement('li', false, 'Flow', 'Common');
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Tables.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Tables.php
index f314ced3f..45c42bb3e 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Tables.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/Tables.php
@@ -37,6 +37,9 @@ class HTMLPurifier_HTMLModule_Tables extends HTMLPurifier_HTMLModule
                 'abbr'    => 'Text',
                 'colspan' => 'Number',
                 'rowspan' => 'Number',
+                // Apparently, as of HTML5 this attribute only applies
+                // to 'th' elements.
+                'scope'   => 'Enum#row,col,rowgroup,colgroup',
             ),
             $cell_align
         );
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/TargetBlank.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/TargetBlank.php
new file mode 100644
index 000000000..e1305ec5d
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModule/TargetBlank.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * Module adds the target=blank attribute transformation to a tags.  It
+ * is enabled by HTML.TargetBlank
+ */
+class HTMLPurifier_HTMLModule_TargetBlank extends HTMLPurifier_HTMLModule
+{
+
+    public $name = 'TargetBlank';
+
+    public function setup($config) {
+        $a = $this->addBlankElement('a');
+        $a->attr_transform_post[] = new HTMLPurifier_AttrTransform_TargetBlank();
+    }
+
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/HTMLModuleManager.php b/lib/htmlpurifier/library/HTMLPurifier/HTMLModuleManager.php
index 362e3b78d..7a06fc022 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/HTMLModuleManager.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/HTMLModuleManager.php
@@ -65,11 +65,11 @@ class HTMLPurifier_HTMLModuleManager
             'Presentation', 'Edit', 'Bdo', 'Tables', 'Image',
             'StyleAttribute',
             // Unsafe:
-            'Scripting', 'Object',  'Forms',
+            'Scripting', 'Object', 'Forms',
             // Sorta legacy, but present in strict:
             'Name',
         );
-        $transitional = array('Legacy', 'Target');
+        $transitional = array('Legacy', 'Target', 'Iframe');
         $xml = array('XMLCommonAttributes');
         $non_xml = array('NonXMLCommonAttributes');
 
@@ -112,7 +112,9 @@ class HTMLPurifier_HTMLModuleManager
 
         $this->doctypes->register(
             'XHTML 1.1', true,
-            array_merge($common, $xml, array('Ruby')),
+            // Iframe is a real XHTML 1.1 module, despite being
+            // "transitional"!
+            array_merge($common, $xml, array('Ruby', 'Iframe')),
             array('Tidy_Strict', 'Tidy_XHTML', 'Tidy_Proprietary', 'Tidy_Strict', 'Tidy_Name'), // Tidy_XHTML1_1
             array(),
             '-//W3C//DTD XHTML 1.1//EN',
@@ -229,6 +231,9 @@ class HTMLPurifier_HTMLModuleManager
         if ($config->get('HTML.Nofollow')) {
             $modules[] = 'Nofollow';
         }
+        if ($config->get('HTML.TargetBlank')) {
+            $modules[] = 'TargetBlank';
+        }
 
         // merge in custom modules
         $modules = array_merge($modules, $this->userModules);
@@ -364,6 +369,13 @@ class HTMLPurifier_HTMLModuleManager
                 // :TODO:
                 // non-standalone definitions that don't have a standalone
                 // to merge into could be deferred to the end
+                // HOWEVER, it is perfectly valid for a non-standalone
+                // definition to lack a standalone definition, even
+                // after all processing: this allows us to safely
+                // specify extra attributes for elements that may not be
+                // enabled all in one place.  In particular, this might
+                // be the case for trusted elements.  WARNING: care must
+                // be taken that the /extra/ definitions are all safe.
                 continue;
             }
 
diff --git a/lib/htmlpurifier/library/HTMLPurifier/Lexer/PEARSax3.php b/lib/htmlpurifier/library/HTMLPurifier/Lexer/PEARSax3.php
deleted file mode 100644
index 1d358c7b6..000000000
--- a/lib/htmlpurifier/library/HTMLPurifier/Lexer/PEARSax3.php
+++ /dev/null
@@ -1,139 +0,0 @@
-<?php
-
-/**
- * Proof-of-concept lexer that uses the PEAR package XML_HTMLSax3 to parse HTML.
- *
- * PEAR, not suprisingly, also has a SAX parser for HTML.  I don't know
- * very much about implementation, but it's fairly well written.  However, that
- * abstraction comes at a price: performance. You need to have it installed,
- * and if the API changes, it might break our adapter. Not sure whether or not
- * it's UTF-8 aware, but it has some entity parsing trouble (in all areas,
- * text and attributes).
- *
- * Quite personally, I don't recommend using the PEAR class, and the defaults
- * don't use it. The unit tests do perform the tests on the SAX parser too, but
- * whatever it does for poorly formed HTML is up to it.
- *
- * @todo Generalize so that XML_HTMLSax is also supported.
- *
- * @warning Entity-resolution inside attributes is broken.
- */
-
-class HTMLPurifier_Lexer_PEARSax3 extends HTMLPurifier_Lexer
-{
-
-    /**
-     * Internal accumulator array for SAX parsers.
-     */
-    protected $tokens = array();
-    protected $last_token_was_empty;
-
-    private $parent_handler;
-    private $stack = array();
-
-    public function tokenizeHTML($string, $config, $context) {
-
-        $this->tokens = array();
-        $this->last_token_was_empty = false;
-
-        $string = $this->normalize($string, $config, $context);
-
-        $this->parent_handler = set_error_handler(array($this, 'muteStrictErrorHandler'));
-
-        $parser = new XML_HTMLSax3();
-        $parser->set_object($this);
-        $parser->set_element_handler('openHandler','closeHandler');
-        $parser->set_data_handler('dataHandler');
-        $parser->set_escape_handler('escapeHandler');
-
-        // doesn't seem to work correctly for attributes
-        $parser->set_option('XML_OPTION_ENTITIES_PARSED', 1);
-
-        $parser->parse($string);
-
-        restore_error_handler();
-
-        return $this->tokens;
-
-    }
-
-    /**
-     * Open tag event handler, interface is defined by PEAR package.
-     */
-    public function openHandler(&$parser, $name, $attrs, $closed) {
-        // entities are not resolved in attrs
-        foreach ($attrs as $key => $attr) {
-            $attrs[$key] = $this->parseData($attr);
-        }
-        if ($closed) {
-            $this->tokens[] = new HTMLPurifier_Token_Empty($name, $attrs);
-            $this->last_token_was_empty = true;
-        } else {
-            $this->tokens[] = new HTMLPurifier_Token_Start($name, $attrs);
-        }
-        $this->stack[] = $name;
-        return true;
-    }
-
-    /**
-     * Close tag event handler, interface is defined by PEAR package.
-     */
-    public function closeHandler(&$parser, $name) {
-        // HTMLSax3 seems to always send empty tags an extra close tag
-        // check and ignore if you see it:
-        // [TESTME] to make sure it doesn't overreach
-        if ($this->last_token_was_empty) {
-            $this->last_token_was_empty = false;
-            return true;
-        }
-        $this->tokens[] = new HTMLPurifier_Token_End($name);
-        if (!empty($this->stack)) array_pop($this->stack);
-        return true;
-    }
-
-    /**
-     * Data event handler, interface is defined by PEAR package.
-     */
-    public function dataHandler(&$parser, $data) {
-        $this->last_token_was_empty = false;
-        $this->tokens[] = new HTMLPurifier_Token_Text($data);
-        return true;
-    }
-
-    /**
-     * Escaped text handler, interface is defined by PEAR package.
-     */
-    public function escapeHandler(&$parser, $data) {
-        if (strpos($data, '--') === 0) {
-            // remove trailing and leading double-dashes
-            $data = substr($data, 2);
-            if (strlen($data) >= 2 && substr($data, -2) == "--") {
-                $data = substr($data, 0, -2);
-            }
-            if (isset($this->stack[sizeof($this->stack) - 1]) &&
-                $this->stack[sizeof($this->stack) - 1] == "style") {
-                $this->tokens[] = new HTMLPurifier_Token_Text($data);
-            } else {
-                $this->tokens[] = new HTMLPurifier_Token_Comment($data);
-            }
-            $this->last_token_was_empty = false;
-        }
-        // CDATA is handled elsewhere, but if it was handled here:
-        //if (strpos($data, '[CDATA[') === 0) {
-        //    $this->tokens[] = new HTMLPurifier_Token_Text(
-        //        substr($data, 7, strlen($data) - 9) );
-        //}
-        return true;
-    }
-
-    /**
-     * An error handler that mutes strict errors
-     */
-    public function muteStrictErrorHandler($errno, $errstr, $errfile=null, $errline=null, $errcontext=null) {
-        if ($errno == E_STRICT) return;
-        return call_user_func($this->parent_handler, $errno, $errstr, $errfile, $errline, $errcontext);
-    }
-
-}
-
-// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/Strategy/Composite.php b/lib/htmlpurifier/library/HTMLPurifier/Strategy/Composite.php
index 816490b79..92aefd33e 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/Strategy/Composite.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/Strategy/Composite.php
@@ -11,8 +11,6 @@ abstract class HTMLPurifier_Strategy_Composite extends HTMLPurifier_Strategy
      */
     protected $strategies = array();
 
-    abstract public function __construct();
-
     public function execute($tokens, $config, $context) {
         foreach ($this->strategies as $strategy) {
             $tokens = $strategy->execute($tokens, $config, $context);
diff --git a/lib/htmlpurifier/library/HTMLPurifier/Strategy/RemoveForeignElements.php b/lib/htmlpurifier/library/HTMLPurifier/Strategy/RemoveForeignElements.php
index cf3a33e40..bccaf14d3 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/Strategy/RemoveForeignElements.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/Strategy/RemoveForeignElements.php
@@ -21,6 +21,9 @@ class HTMLPurifier_Strategy_RemoveForeignElements extends HTMLPurifier_Strategy
 
         // currently only used to determine if comments should be kept
         $trusted = $config->get('HTML.Trusted');
+        $comment_lookup = $config->get('HTML.AllowedComments');
+        $comment_regexp = $config->get('HTML.AllowedCommentsRegexp');
+        $check_comments = $comment_lookup !== array() || $comment_regexp !== null;
 
         $remove_script_contents = $config->get('Core.RemoveScriptContents');
         $hidden_elements     = $config->get('Core.HiddenElements');
@@ -128,23 +131,37 @@ class HTMLPurifier_Strategy_RemoveForeignElements extends HTMLPurifier_Strategy
                 if ($textify_comments !== false) {
                     $data = $token->data;
                     $token = new HTMLPurifier_Token_Text($data);
-                } elseif ($trusted) {
-                    // keep, but perform comment cleaning
+                } elseif ($trusted || $check_comments) {
+                    // always cleanup comments
+                    $trailing_hyphen = false;
                     if ($e) {
                         // perform check whether or not there's a trailing hyphen
                         if (substr($token->data, -1) == '-') {
-                            $e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Trailing hyphen in comment removed');
+                            $trailing_hyphen = true;
                         }
                     }
                     $token->data = rtrim($token->data, '-');
                     $found_double_hyphen = false;
                     while (strpos($token->data, '--') !== false) {
-                        if ($e && !$found_double_hyphen) {
-                            $e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Hyphens in comment collapsed');
-                        }
-                        $found_double_hyphen = true; // prevent double-erroring
+                        $found_double_hyphen = true;
                         $token->data = str_replace('--', '-', $token->data);
                     }
+                    if ($trusted || !empty($comment_lookup[trim($token->data)]) || ($comment_regexp !== NULL && preg_match($comment_regexp, trim($token->data)))) {
+                        // OK good
+                        if ($e) {
+                            if ($trailing_hyphen) {
+                                $e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Trailing hyphen in comment removed');
+                            }
+                            if ($found_double_hyphen) {
+                                $e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Hyphens in comment collapsed');
+                            }
+                        }
+                    } else {
+                        if ($e) {
+                            $e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Comment removed');
+                        }
+                        continue;
+                    }
                 } else {
                     // strip comments
                     if ($e) $e->send(E_NOTICE, 'Strategy_RemoveForeignElements: Comment removed');
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URI.php b/lib/htmlpurifier/library/HTMLPurifier/URI.php
index efdfb2c68..f158ef5e3 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URI.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URI.php
@@ -40,7 +40,7 @@ class HTMLPurifier_URI
         } else {
             // no scheme: retrieve the default one
             $def = $config->getDefinition('URI');
-            $scheme_obj = $registry->getScheme($def->defaultScheme, $config, $context);
+            $scheme_obj = $def->getDefaultScheme($config, $context);
             if (!$scheme_obj) {
                 // something funky happened to the default scheme object
                 trigger_error(
@@ -199,6 +199,44 @@ class HTMLPurifier_URI
         return $result;
     }
 
+    /**
+     * Returns true if this URL might be considered a 'local' URL given
+     * the current context.  This is true when the host is null, or
+     * when it matches the host supplied to the configuration.
+     *
+     * Note that this does not do any scheme checking, so it is mostly
+     * only appropriate for metadata that doesn't care about protocol
+     * security.  isBenign is probably what you actually want.
+     */
+    public function isLocal($config, $context) {
+        if ($this->host === null) return true;
+        $uri_def = $config->getDefinition('URI');
+        if ($uri_def->host === $this->host) return true;
+        return false;
+    }
+
+    /**
+     * Returns true if this URL should be considered a 'benign' URL,
+     * that is:
+     *
+     *      - It is a local URL (isLocal), and
+     *      - It has a equal or better level of security
+     */
+    public function isBenign($config, $context) {
+        if (!$this->isLocal($config, $context)) return false;
+
+        $scheme_obj = $this->getSchemeObj($config, $context);
+        if (!$scheme_obj) return false; // conservative approach
+
+        $current_scheme_obj = $config->getDefinition('URI')->getDefaultScheme($config, $context);
+        if ($current_scheme_obj->secure) {
+            if (!$scheme_obj->secure) {
+                return false;
+            }
+        }
+        return true;
+    }
+
 }
 
 // vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIDefinition.php b/lib/htmlpurifier/library/HTMLPurifier/URIDefinition.php
index ea2b8fe24..40e57bb7d 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIDefinition.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIDefinition.php
@@ -27,6 +27,7 @@ class HTMLPurifier_URIDefinition extends HTMLPurifier_Definition
         $this->registerFilter(new HTMLPurifier_URIFilter_DisableExternal());
         $this->registerFilter(new HTMLPurifier_URIFilter_DisableExternalResources());
         $this->registerFilter(new HTMLPurifier_URIFilter_HostBlacklist());
+        $this->registerFilter(new HTMLPurifier_URIFilter_SafeIframe());
         $this->registerFilter(new HTMLPurifier_URIFilter_MakeAbsolute());
         $this->registerFilter(new HTMLPurifier_URIFilter_Munge());
     }
@@ -52,9 +53,13 @@ class HTMLPurifier_URIDefinition extends HTMLPurifier_Definition
 
     protected function setupFilters($config) {
         foreach ($this->registeredFilters as $name => $filter) {
-            $conf = $config->get('URI.' . $name);
-            if ($conf !== false && $conf !== null) {
+            if ($filter->always_load) {
                 $this->addFilter($filter, $config);
+            } else {
+                $conf = $config->get('URI.' . $name);
+                if ($conf !== false && $conf !== null) {
+                    $this->addFilter($filter, $config);
+                }
             }
         }
         unset($this->registeredFilters);
@@ -72,6 +77,10 @@ class HTMLPurifier_URIDefinition extends HTMLPurifier_Definition
         if (is_null($this->defaultScheme)) $this->defaultScheme = $config->get('URI.DefaultScheme');
     }
 
+    public function getDefaultScheme($config, $context) {
+        return HTMLPurifier_URISchemeRegistry::instance()->getScheme($this->defaultScheme, $config, $context);
+    }
+
     public function filter(&$uri, $config, $context) {
         foreach ($this->filters as $name => $f) {
             $result = $f->filter($uri, $config, $context);
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php b/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php
index c116f93df..6a1b0b08e 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIFilter.php
@@ -4,7 +4,21 @@
  * Chainable filters for custom URI processing.
  *
  * These filters can perform custom actions on a URI filter object,
- * including transformation or blacklisting.
+ * including transformation or blacklisting.  A filter named Foo
+ * must have a corresponding configuration directive %URI.Foo,
+ * unless always_load is specified to be true.
+ *
+ * The following contexts may be available while URIFilters are being
+ * processed:
+ *
+ *      - EmbeddedURI: true if URI is an embedded resource that will
+ *        be loaded automatically on page load
+ *      - CurrentToken: a reference to the token that is currently
+ *        being processed
+ *      - CurrentAttr: the name of the attribute that is currently being
+ *        processed
+ *      - CurrentCSSProperty: the name of the CSS property that is
+ *        currently being processed (if applicable)
  *
  * @warning This filter is called before scheme object validation occurs.
  *          Make sure, if you require a specific scheme object, you
@@ -25,7 +39,15 @@ abstract class HTMLPurifier_URIFilter
     public $post = false;
 
     /**
-     * Performs initialization for the filter
+     * True if this filter should always be loaded (this permits
+     * a filter to be named Foo without the corresponding %URI.Foo
+     * directive existing.)
+     */
+    public $always_load = false;
+
+    /**
+     * Performs initialization for the filter.  If the filter returns
+     * false, this means that it shouldn't be considered active.
      */
     public function prepare($config) {return true;}
 
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIFilter/HostBlacklist.php b/lib/htmlpurifier/library/HTMLPurifier/URIFilter/HostBlacklist.php
index 045aa0992..55fde3bf4 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIFilter/HostBlacklist.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIFilter/HostBlacklist.php
@@ -1,5 +1,9 @@
 <?php
 
+// It's not clear to me whether or not Punycode means that hostnames
+// do not have canonical forms anymore. As far as I can tell, it's
+// not a problem (punycoding should be identity when no Unicode
+// points are involved), but I'm not 100% sure
 class HTMLPurifier_URIFilter_HostBlacklist extends HTMLPurifier_URIFilter
 {
     public $name = 'HostBlacklist';
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIFilter/Munge.php b/lib/htmlpurifier/library/HTMLPurifier/URIFilter/Munge.php
index efa10a645..de695df14 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIFilter/Munge.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIFilter/Munge.php
@@ -20,13 +20,8 @@ class HTMLPurifier_URIFilter_Munge extends HTMLPurifier_URIFilter
 
         $scheme_obj = $uri->getSchemeObj($config, $context);
         if (!$scheme_obj) return true; // ignore unknown schemes, maybe another postfilter did it
-        if (is_null($uri->host) || empty($scheme_obj->browsable)) {
-            return true;
-        }
-        // don't redirect if target host is our host
-        if ($uri->host === $config->getDefinition('URI')->host) {
-            return true;
-        }
+        if (!$scheme_obj->browsable) return true; // ignore non-browseable schemes, since we can't munge those in a reasonable way
+        if ($uri->isBenign($config, $context)) return true; // don't redirect if a benign URL
 
         $this->makeReplace($uri, $config, $context);
         $this->replace = array_map('rawurlencode', $this->replace);
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIFilter/SafeIframe.php b/lib/htmlpurifier/library/HTMLPurifier/URIFilter/SafeIframe.php
new file mode 100644
index 000000000..284bb13de
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIFilter/SafeIframe.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Implements safety checks for safe iframes.
+ *
+ * @warning This filter is *critical* for ensuring that %HTML.SafeIframe
+ * works safely.
+ */
+class HTMLPurifier_URIFilter_SafeIframe extends HTMLPurifier_URIFilter
+{
+    public $name = 'SafeIframe';
+    public $always_load = true;
+    protected $regexp = NULL;
+    // XXX: The not so good bit about how this is all setup now is we
+    // can't check HTML.SafeIframe in the 'prepare' step: we have to
+    // defer till the actual filtering.
+    public function prepare($config) {
+        $this->regexp = $config->get('URI.SafeIframeRegexp');
+        return true;
+    }
+    public function filter(&$uri, $config, $context) {
+        // check if filter not applicable
+        if (!$config->get('HTML.SafeIframe')) return true;
+        // check if the filter should actually trigger
+        if (!$context->get('EmbeddedURI', true)) return true;
+        $token = $context->get('CurrentToken', true);
+        if (!($token && $token->name == 'iframe')) return true;
+        // check if we actually have some whitelists enabled
+        if ($this->regexp === null) return false;
+        // actually check the whitelists
+        return preg_match($this->regexp, $uri->toString());
+    }
+}
+
+// vim: et sw=4 sts=4
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIScheme.php b/lib/htmlpurifier/library/HTMLPurifier/URIScheme.php
index 25eb8410b..7be958143 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIScheme.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIScheme.php
@@ -20,6 +20,12 @@ abstract class HTMLPurifier_URIScheme
     public $browsable = false;
 
     /**
+     * Whether or not data transmitted over this scheme is encrypted.
+     * https is secure, http is not.
+     */
+    public $secure = false;
+
+    /**
      * Whether or not the URI always uses <hier_part>, resolves edge cases
      * with making relative URIs absolute
      */
diff --git a/lib/htmlpurifier/library/HTMLPurifier/URIScheme/https.php b/lib/htmlpurifier/library/HTMLPurifier/URIScheme/https.php
index 29e380919..159c2874e 100644
--- a/lib/htmlpurifier/library/HTMLPurifier/URIScheme/https.php
+++ b/lib/htmlpurifier/library/HTMLPurifier/URIScheme/https.php
@@ -6,6 +6,7 @@
 class HTMLPurifier_URIScheme_https extends HTMLPurifier_URIScheme_http {
 
     public $default_port = 443;
+    public $secure = true;
 
 }