[3.1.2] Add %Output.SortAttr to deal with FCKeditor bug

If %Output.SortAttr is true, attributes are sorted to be
in alphabetical order. This was requested by frank farmer.

See also: http://htmlpurifier.org/phorum/read.php?2,1576

Signed-off-by: Edward Z. Yang <edwardzyang@thewritingpot.com>

NEWS

@@ -12,6 +12,8 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
 3.2.0, unknown release date
 
 3.1.2, unknown release date
+! %Output.AttrSort for when you need your attributes in alphabetical order to
+  deal with a bug in FCKEditor. Requested by frank farmer.
 
 3.1.1, released 2008-06-19
 # %URI.Munge now, by default, does not munge resources (for example, <img src="">)

configdoc/usage.xml

@@ -96,17 +96,22 @@
  </directive>
  <directive id="Output.CommentScriptContents">
   <file name="HTMLPurifier/Generator.php">
-   <line>40</line>
+   <line>45</line>
+  </file>
+ </directive>
+ <directive id="Output.SortAttr">
+  <file name="HTMLPurifier/Generator.php">
+   <line>46</line>
   </file>
  </directive>
  <directive id="Output.TidyFormat">
   <file name="HTMLPurifier/Generator.php">
-   <line>69</line>
+   <line>75</line>
   </file>
  </directive>
  <directive id="Output.Newline">
   <file name="HTMLPurifier/Generator.php">
-   <line>83</line>
+   <line>89</line>
   </file>
  </directive>
  <directive id="HTML.BlockWrapper">

library/HTMLPurifier/ConfigSchema/schema/Output.SortAttr.txt

@@ -0,0 +1,13 @@
+Output.SortAttr
+TYPE: bool
+VERSION: 3.1.2
+DEFAULT: false
+--DESCRIPTION--
+<p>
+  If true, HTML Purifier will sort attributes by name before writing them back
+  to the document, converting a tag like: <code>&lt;el b="" a="" c="" /&gt;</code>
+  to <code>&lt;el a="" b="" c="" /&gt;</code>. This is a workaround for
+  a bug in FCKeditor which causes it to swap attributes order, adding noise
+  to text diffs. If you're not seeing this bug, chances are, you don't need
+  this directive.
+</p>

library/HTMLPurifier/Generator.php

@@ -26,6 +26,11 @@ class HTMLPurifier_Generator
      */
     private $_def;
     
+    /**
+     * Cache of %Output.SortAttr
+     */
+    private $_sortAttr;
+    
     /**
      * Configuration for the generator
      */
@@ -38,6 +43,7 @@ class HTMLPurifier_Generator
     public function __construct($config, $context) {
         $this->config = $config;
         $this->_scriptFix = $config->get('Output', 'CommentScriptContents');
+        $this->_sortAttr = $config->get('Output', 'SortAttr');
         $this->_def = $config->getHTMLDefinition();
         $this->_xhtml = $this->_def->doctype->xml;
     }
@@ -142,6 +148,7 @@ class HTMLPurifier_Generator
      */
     public function generateAttributes($assoc_array_of_attributes, $element = false) {
         $html = '';
+        if ($this->_sortAttr) ksort($assoc_array_of_attributes);
         foreach ($assoc_array_of_attributes as $key => $value) {
             if (!$this->_xhtml) {
                 // Remove namespaced attributes

tests/HTMLPurifier/GeneratorTest.php

@@ -209,7 +209,6 @@ class HTMLPurifier_GeneratorTest extends HTMLPurifier_Harness
     }
     
     function test_generateFromTokens_XHTMLoff() {
-        $this->config = HTMLPurifier_Config::createDefault();
         $this->config->set('HTML', 'XHTML', false);
         
         // omit trailing slash
@@ -237,7 +236,6 @@ class HTMLPurifier_GeneratorTest extends HTMLPurifier_Harness
         // just don't test; Tidy is exploding on me.
         return;
         
-        $this->config = HTMLPurifier_Config::createDefault();
         $this->config->set('Core', 'TidyFormat', true);
         $this->config->set('Output', 'Newline', "\n");
         
@@ -253,5 +251,15 @@ class HTMLPurifier_GeneratorTest extends HTMLPurifier_Harness
         
     }
     
+    function test_generateFromTokens_sortAttr() {
+        $this->config->set('Output', 'SortAttr', true);
+        
+        $this->assertGeneration(
+            array( new HTMLPurifier_Token_Start('p', array('b'=>'c', 'a'=>'d')) ),
+            '<p a="d" b="c">'
+        );
+        
+    }
+    
 }