protected function createDirectory($directory)
{
// create parent directory if needed
$parent = \Gaufrette\Util\Path::dirname($directory);
if (!$this->isDir($parent)) {
$this->createDirectory($parent);
}
// create the specified directory
$created = ftp_mkdir($this->getConnection(), $directory);
if (false === $created) {
throw new \RuntimeException(sprintf('Could not create the \'%s\' directory.', $directory));
}
}