/**
* Prune this directory if it is empty.
*
* @return NULL
*/
private function _prune()
{
if (empty($this->_files) && empty($this->_subdirectories)) {
$this->_element->delete();
if ($this->_parent instanceof Horde_Pear_Package_Xml_Directory) {
$this->_parent->_deleteSubdirectory($this->_element->getName());
}
}
}