/** * Test if folder is subfolder of its parent folder. * * @param string $subfolder absolute path to folder which we need test * @param string $folder absolute path to tested folder parent folder * @return mixed true/false/null - is subfolder/is not subfolder/unable test */ public static function isSubFolder($subfolder, $folder) { $subfolder = JPath::clean($subfolder); $folder = JPath::clean($folder); if (!JoomDOCFileSystem::exists($subfolder) || !JoomDOCFileSystem::exists($folder)) { return null; } return JString::strpos($subfolder, $folder) === 0; }