Implement "carryover" functionality, requested by Kinderlehrer <bitweaver@7doves.com>

This commit is a limited implementation of the "active formatting
elements" algorithm implemented in HTML5, which preserves certain
formatting elements such as <a> and <b> when exiting or entering nodes.

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

library/HTMLPurifier/ChildDef.php

@@ -28,7 +28,7 @@ abstract class HTMLPurifier_ChildDef
      * Get lookup of tag names that should not close this element automatically.
      * All other elements will do so.
      */
-    public function getNonAutoCloseElements($config) {
+    public function getAllowedElements($config) {
         return $this->elements;
     }
 

library/HTMLPurifier/ChildDef/StrictBlockquote.php

@@ -15,7 +15,7 @@ class HTMLPurifier_ChildDef_StrictBlockquote extends HTMLPurifier_ChildDef_Requi
      * @note We don't want MakeWellFormed to auto-close inline elements since
      *       they might be allowed.
      */
-    public function getNonAutoCloseElements($config) {
+    public function getAllowedElements($config) {
         $this->init($config);
         return $this->fake_elements;
     }

library/HTMLPurifier/ElementDef.php

@@ -5,6 +5,8 @@
  * HTMLPurifier_HTMLDefinition and HTMLPurifier_HTMLModule.
  * @note This class is inspected by HTMLPurifier_Printer_HTMLDefinition.
  *       Please update that class too.
+ * @warning If you add new properties to this class, you MUST update
+ *          the mergeIn() method.
  */
 class HTMLPurifier_ElementDef
 {
@@ -90,6 +92,17 @@ class HTMLPurifier_ElementDef
      */
     public $excludes = array();
 
+    /**
+     * This tag is explicitly auto-closed by the following tags.
+     */
+    public $autoclose = array();
+
+    /**
+     * Whether or not this is a formatting element affected by the
+     * "Active Formatting Elements" algorithm.
+     */
+    public $formatting;
+
     /**
      * Low-level factory constructor for creating new standalone element defs
      */
@@ -137,6 +150,7 @@ class HTMLPurifier_ElementDef
             $this->child = false;
         }
         if(!is_null($def->child)) $this->child = $def->child;
+        if(!is_null($def->formatting)) $this->formatting = $def->formatting;
         if($def->descendants_are_inline) $this->descendants_are_inline = $def->descendants_are_inline;
 
     }

library/HTMLPurifier/HTMLModule/Hypertext.php

@@ -22,6 +22,7 @@ class HTMLPurifier_HTMLModule_Hypertext extends HTMLPurifier_HTMLModule
                 // 'type' => 'ContentType',
             )
         );
+        $a->formatting = true;
         $a->excludes = array('a' => true);
     }
 

library/HTMLPurifier/HTMLModule/Legacy.php

@@ -41,9 +41,15 @@ class HTMLPurifier_HTMLModule_Legacy extends HTMLPurifier_HTMLModule
         $this->addElement('menu', 'Block', 'Required: li', 'Common', array(
             'compact' => 'Bool#compact'
         ));
-        $this->addElement('s', 'Inline', 'Inline', 'Common');
-        $this->addElement('strike', 'Inline', 'Inline', 'Common');
-        $this->addElement('u', 'Inline', 'Inline', 'Common');
+
+        $s = $this->addElement('s', 'Inline', 'Inline', 'Common');
+        $s->formatting = true;
+
+        $strike = $this->addElement('strike', 'Inline', 'Inline', 'Common');
+        $strike->formatting = true;
+
+        $u = $this->addElement('u', 'Inline', 'Inline', 'Common');
+        $u->formatting = true;
 
         // setup modifications to old elements
 

library/HTMLPurifier/HTMLModule/Presentation.php

@@ -16,14 +16,19 @@ class HTMLPurifier_HTMLModule_Presentation extends HTMLPurifier_HTMLModule
     public $name = 'Presentation';
 
     public function setup($config) {
-        $this->addElement('b',      'Inline', 'Inline', 'Common');
-        $this->addElement('big',    'Inline', 'Inline', 'Common');
         $this->addElement('hr',     'Block',  'Empty',  'Common');
-        $this->addElement('i',      'Inline', 'Inline', 'Common');
-        $this->addElement('small',  'Inline', 'Inline', 'Common');
         $this->addElement('sub',    'Inline', 'Inline', 'Common');
         $this->addElement('sup',    'Inline', 'Inline', 'Common');
-        $this->addElement('tt',     'Inline', 'Inline', 'Common');
+        $b = $this->addElement('b',      'Inline', 'Inline', 'Common');
+        $b->formatting = true;
+        $big = $this->addElement('big',    'Inline', 'Inline', 'Common');
+        $big->formatting = true;
+        $i = $this->addElement('i',      'Inline', 'Inline', 'Common');
+        $i->formatting = true;
+        $small = $this->addElement('small',  'Inline', 'Inline', 'Common');
+        $small->formatting = true;
+        $tt = $this->addElement('tt',     'Inline', 'Inline', 'Common');
+        $tt->formatting = true;
     }
 
 }

library/HTMLPurifier/HTMLModule/Text.php

@@ -26,15 +26,21 @@ class HTMLPurifier_HTMLModule_Text extends HTMLPurifier_HTMLModule
         $this->addElement('abbr',    'Inline', 'Inline', 'Common');
         $this->addElement('acronym', 'Inline', 'Inline', 'Common');
         $this->addElement('cite',    'Inline', 'Inline', 'Common');
-        $this->addElement('code',    'Inline', 'Inline', 'Common');
         $this->addElement('dfn',     'Inline', 'Inline', 'Common');
-        $this->addElement('em',      'Inline', 'Inline', 'Common');
         $this->addElement('kbd',     'Inline', 'Inline', 'Common');
         $this->addElement('q',       'Inline', 'Inline', 'Common', array('cite' => 'URI'));
         $this->addElement('samp',    'Inline', 'Inline', 'Common');
-        $this->addElement('strong',  'Inline', 'Inline', 'Common');
         $this->addElement('var',     'Inline', 'Inline', 'Common');
 
+        $em = $this->addElement('em',      'Inline', 'Inline', 'Common');
+        $em->formatting = true;
+
+        $strong = $this->addElement('strong',  'Inline', 'Inline', 'Common');
+        $strong->formatting = true;
+
+        $code = $this->addElement('code',    'Inline', 'Inline', 'Common');
+        $code->formatting = true;
+
         // Inline Structural ----------------------------------------------
         $this->addElement('span', 'Inline', 'Inline', 'Common');
         $this->addElement('br',   'Inline', 'Empty',  'Core');
@@ -53,7 +59,9 @@ class HTMLPurifier_HTMLModule_Text extends HTMLPurifier_HTMLModule
         $this->addElement('h6', 'Heading', 'Inline', 'Common');
 
         // Block Structural -----------------------------------------------
-        $this->addElement('p', 'Block', 'Inline', 'Common');
+        $p = $this->addElement('p', 'Block', 'Inline', 'Common');
+        $p->autoclose = array_flip(array("address", "blockquote", "center", "dir", "div", "dl", "fieldset", "ol", "p", "ul"));
+
         $this->addElement('div', 'Block', 'Flow', 'Common');
 
     }

library/HTMLPurifier/Language/messages/en.php

@@ -37,6 +37,7 @@ $messages = array(
 'Strategy_MakeWellFormed: Unnecessary end tag removed' => 'Unnecessary $CurrentToken.Serialized tag removed',
 'Strategy_MakeWellFormed: Unnecessary end tag to text' => 'Unnecessary $CurrentToken.Serialized tag converted to text',
 'Strategy_MakeWellFormed: Tag auto closed'             => '$1.Compact started on line $1.Line auto-closed by $CurrentToken.Compact',
+'Strategy_MakeWellFormed: Tag carryover'               => '$1.Compact started on line $1.Line auto-continued into $CurrentToken.Compact',
 'Strategy_MakeWellFormed: Stray end tag removed'       => 'Stray $CurrentToken.Serialized tag removed',
 'Strategy_MakeWellFormed: Stray end tag to text'       => 'Stray $CurrentToken.Serialized tag converted to text',
 'Strategy_MakeWellFormed: Tag closed by element end'   => '$1.Compact tag started on line $1.Line closed by end of $CurrentToken.Serialized',

library/HTMLPurifier/Strategy/MakeWellFormed.php

@@ -159,12 +159,9 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
                 continue;
             }
 
-            // if all goes well, this token will be passed through unharmed
             $token = $tokens[$t];
 
-            //echo '<hr>';
-            //printTokens($tokens, $t);
-            //var_dump($this->stack);
+            //echo '<br>'; printTokens($tokens, $t); printTokens($this->stack);
 
             // quick-check: if it's not a tag, no need to process
             if (empty($token->is_tag)) {
@@ -214,18 +211,36 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
                     $this->stack[] = $parent;
 
                     if (isset($definition->info[$parent->name])) {
-                        $elements = $definition->info[$parent->name]->child->getNonAutoCloseElements($config);
+                        $elements = $definition->info[$parent->name]->child->getAllowedElements($config);
                         $autoclose = !isset($elements[$token->name]);
                     } else {
                         $autoclose = false;
                     }
 
+                    $carryover = false;
+                    if ($autoclose && $definition->info[$parent->name]->formatting) {
+                        $carryover = true;
+                    }
+
                     if ($autoclose) {
-                        if ($e) $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent);
-                        // insert parent end tag before this tag
+                        // errors need to be updated
                         $new_token = new HTMLPurifier_Token_End($parent->name);
                         $new_token->start = $parent;
-                        $this->insertBefore($new_token);
+                        if ($carryover) {
+                            $element = clone $parent;
+                            $element->armor['MakeWellFormed_TagClosedError'] = true;
+                            $element->carryover = true;
+                            $this->processToken(array($new_token, $token, $element));
+                        } else {
+                            $this->insertBefore($new_token);
+                        }
+                        if ($e && !isset($parent->armor['MakeWellFormed_TagClosedError'])) {
+                            if (!$carryover) {
+                                $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent);
+                            } else {
+                                $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag carryover', $parent);
+                            }
+                        }
                         $reprocess = true;
                         continue;
                     }
@@ -339,12 +354,20 @@ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
             }
 
             // insert tags, in FORWARD $j order: c,b,a with </a></b></c>
+            $replace = array($token);
             for ($j = 1; $j < $c; $j++) {
                 // ...as well as from the insertions
                 $new_token = new HTMLPurifier_Token_End($skipped_tags[$j]->name);
                 $new_token->start = $skipped_tags[$j];
-                $this->insertBefore($new_token);
+                array_unshift($replace, $new_token);
+                if (isset($definition->info[$new_token->name]) && $definition->info[$new_token->name]->formatting) {
+                    $element = clone $skipped_tags[$j];
+                    $element->carryover = true;
+                    $element->armor['MakeWellFormed_TagClosedError'] = true;
+                    $replace[] = $element;
+                }
             }
+            $this->processToken($replace);
             $reprocess = true;
             continue;
         }

library/HTMLPurifier/TagTransform/Font.php

@@ -11,6 +11,9 @@
  *       Thanks to
  *       http://style.cleverchimp.com/font_size_intervals/altintervals.html
  *       for reasonable mappings.
+ * @warning This doesn't work completely correctly; specifically, this
+ *          TagTransform operates before well-formedness is enforced, so
+ *          the "active formatting elements" algorithm doesn't get applied.
  */
 class HTMLPurifier_TagTransform_Font extends HTMLPurifier_TagTransform
 {

library/HTMLPurifier/Token.php

@@ -19,6 +19,7 @@ class HTMLPurifier_Token {
      */
     public $skip;
     public $rewind;
+    public $carryover;
 
     public function __get($n) {
       if ($n === 'type') {

tests/HTMLPurifier/HTMLT/inline-wraps-block.htmlt

@@ -0,0 +1,5 @@
+--HTML--
+<a href="foo.html"><h1>Foobar</h1></a>
+--EXPECT--
+<a href="foo.html"></a><h1><a href="foo.html">Foobar</a></h1><a href="foo.html"></a>
+--# vim: et sw=4 sts=4

tests/HTMLPurifier/Harness.php

@@ -6,8 +6,8 @@
 class HTMLPurifier_Harness extends UnitTestCase
 {
 
-    public function __construct() {
-        parent::__construct();
+    public function __construct($name = null) {
+        parent::__construct($name);
     }
 
     protected $config, $context, $purifier;

tests/HTMLPurifier/Strategy/CoreTest.php

@@ -22,7 +22,7 @@ class HTMLPurifier_Strategy_CoreTest extends HTMLPurifier_StrategyHarness
     function testFixNesting() {
         $this->assertResult(
             '<b><div>Fix nesting.</div></b>',
-            '<b></b><div>Fix nesting.</div>'
+            '<b></b><div><b>Fix nesting.</b></div><b></b>'
         );
     }
 
@@ -36,7 +36,7 @@ class HTMLPurifier_Strategy_CoreTest extends HTMLPurifier_StrategyHarness
     function testFirstThree() {
         $this->assertResult(
             '<foo><b><div>All three.</div></b>',
-            '<b></b><div>All three.</div>'
+            '<b></b><div><b>All three.</b></div><b></b>'
         );
     }
 

tests/HTMLPurifier/Strategy/MakeWellFormed/EndInsertInjectorTest.php

@@ -22,7 +22,7 @@ class HTMLPurifier_Strategy_MakeWellFormed_EndInsertInjectorTest extends HTMLPur
         $this->assertResult('<i><i>Foo', '<i><i>Foo<b>Comment</b></i><b>Comment</b></i>');
     }
     function testEndOfNodeProcessing() {
-        $this->assertResult('<div><i>Foo</div>', '<div><i>Foo<b>Comment</b></i></div>');
+        $this->assertResult('<div><i>Foo</div>asdf', '<div><i>Foo<b>Comment</b></i></div><i>asdf<b>Comment</b></i>');
     }
     function testEmptyToStartEndProcessing() {
         $this->assertResult('<i />', '<i><b>Comment</b></i>');

tests/HTMLPurifier/Strategy/MakeWellFormedTest.php

@@ -26,7 +26,7 @@ class HTMLPurifier_Strategy_MakeWellFormedTest extends HTMLPurifier_StrategyHarn
     function testUnclosedTagTerminatedByParentNodeEnd() {
         $this->assertResult(
             '<b><i>Bold and italic?</b>',
-            '<b><i>Bold and italic?</i></b>'
+            '<b><i>Bold and italic?</i></b><i></i>'
         );
     }
 
@@ -81,8 +81,8 @@ class HTMLPurifier_Strategy_MakeWellFormedTest extends HTMLPurifier_StrategyHarn
 
     function testAutoCloseMultiple() {
         $this->assertResult(
-            '<span><span><div></div>',
-            '<span><span></span></span><div></div>'
+            '<b><span><div></div>asdf',
+            '<b><span></span></b><div><b></b></div><b>asdf</b>'
         );
     }
 
@@ -102,6 +102,20 @@ class HTMLPurifier_Strategy_MakeWellFormedTest extends HTMLPurifier_StrategyHarn
         );
     }
 
+    function testLongCarryOver() {
+        $this->assertResult(
+            '<b>asdf<div>asdf<i>df</i></div>asdf</b>',
+            '<b>asdf</b><div><b>asdf<i>df</i></b></div><b>asdf</b>'
+        );
+    }
+
+    function testInterleaved() {
+        $this->assertResult(
+            '<u>foo<i>bar</u>baz</i>',
+            '<u>foo<i>bar</i></u><i>baz</i>'
+        );
+    }
+
 }
 
 // vim: et sw=4 sts=4

tests/HTMLPurifier/Strategy/MakeWellFormed_ErrorsTest.php

@@ -20,8 +20,15 @@ class HTMLPurifier_Strategy_MakeWellFormed_ErrorsTest extends HTMLPurifier_Strat
         $this->invoke('</b>');
     }
 
-    function testTagAutoClosed() {
-        $this->expectErrorCollection(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', new HTMLPurifier_Token_Start('b', array(), 1, 0));
+    function testTagAutoclose() {
+        $this->expectErrorCollection(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', new HTMLPurifier_Token_Start('p', array(), 1, 0));
+        $this->expectContext('CurrentToken', new HTMLPurifier_Token_Start('div', array(), 1, 6));
+        $this->invoke('<p>Foo<div>Bar</div>');
+    }
+
+    function testTagCarryOver() {
+        $b = new HTMLPurifier_Token_Start('b', array(), 1, 0);
+        $this->expectErrorCollection(E_NOTICE, 'Strategy_MakeWellFormed: Tag carryover', $b);
         $this->expectContext('CurrentToken', new HTMLPurifier_Token_Start('div', array(), 1, 6));
         $this->invoke('<b>Foo<div>Bar</div>');
     }