MDL-9151 HTML Purifier cleaning support - enable switch is in experimental section

MDL-9435 Reviewved url cleaning in redirect()

lib/htmlpurifier/HTMLPurifier/ChildDef.php

@@ -0,0 +1,55 @@
+<?php
+
+// HTMLPurifier_ChildDef and inheritance have three types of output:
+// true = leave nodes as is
+// false = delete parent node and all children
+// array(...) = replace children nodes with these
+
+HTMLPurifier_ConfigSchema::define(
+    'Core', 'EscapeInvalidChildren', false, 'bool',
+    'When true, a child is found that is not allowed in the context of the '.
+    'parent element will be transformed into text as if it were ASCII. When '.
+    'false, that element and all internal tags will be dropped, though text '.
+    'will be preserved.  There is no option for dropping the element but '.
+    'preserving child nodes.'
+);
+
+/**
+ * Defines allowed child nodes and validates tokens against it.
+ */
+class HTMLPurifier_ChildDef
+{
+    /**
+     * Type of child definition, usually right-most part of class name lowercase.
+     * Used occasionally in terms of context.
+     * @public
+     */
+    var $type;
+    
+    /**
+     * Bool that indicates whether or not an empty array of children is okay
+     * 
+     * This is necessary for redundant checking when changes affecting
+     * a child node may cause a parent node to now be disallowed.
+     * 
+     * @public
+     */
+    var $allow_empty;
+    
+    /**
+     * Validates nodes according to definition and returns modification.
+     * 
+     * @public
+     * @param $tokens_of_children Array of HTMLPurifier_Token
+     * @param $config HTMLPurifier_Config object
+     * @param $context HTMLPurifier_Context object
+     * @return bool true to leave nodes as is
+     * @return bool false to remove parent node
+     * @return array of replacement child tokens
+     */
+    function validateChildren($tokens_of_children, $config, &$context) {
+        trigger_error('Call to abstract function', E_USER_ERROR);
+    }
+}
+
+?>