protected function samePrefix($url)
{
$partsA = explode('/', $url);
$partsB = explode('/', $this->currentFileName);
$n = count($partsA);
if ($n != count($partsB)) {
return false;
}
unset($partsA[$n - 1]);
unset($partsB[$n - 1]);
return $partsA == $partsB;
}