--- /dev/null
+<?php
+
+/**
+ * Definition that allows a set of elements, and allows no children.
+ * @note This is a hack to reuse code from HTMLPurifier_ChildDef_Required,
+ * really, one shouldn't inherit from the other. Only altered behavior
+ * is to overload a returned false with an array. Thus, it will never
+ * return false.
+ */
+class HTMLPurifier_ChildDef_Optional extends HTMLPurifier_ChildDef_Required
+{
+ /**
+ * @type bool
+ */
+ public $allow_empty = true;
+
+ /**
+ * @type string
+ */
+ public $type = 'optional';
+
+ /**
+ * @param array $children
+ * @param HTMLPurifier_Config $config
+ * @param HTMLPurifier_Context $context
+ * @return array
+ */
+ public function validateChildren($children, $config, $context)
+ {
+ $result = parent::validateChildren($children, $config, $context);
+ // we assume that $children is not modified
+ if ($result === false) {
+ if (empty($children)) {
+ return true;
+ } elseif ($this->whitespace) {
+ return $children;
+ } else {
+ return array();
+ }
+ }
+ return $result;
+ }
+}
+
+// vim: et sw=4 sts=4