protected function _saveFile($data) {
		$uploadKeys = array('name', 'type', 'tmp_name', 'error', 'size');
		$grid = $this->connection->getGridFS();
		$file = null;
		$method = null;

		switch (true) {
			case  (is_array($data['file']) && array_keys($data['file']) == $uploadKeys):
				if (!$data['file']['error'] && is_uploaded_file($data['file']['tmp_name'])) {
					$method = 'storeFile';
					$file = $data['file']['tmp_name'];
					$data['filename'] = $data['file']['name'];
				}
			break;
			case (is_string($data['file']) && file_exists($data['file'])):
				$method = 'storeFile';
				$file = $data['file'];
			break;
			case $data['file']:
				$method = 'storeBytes';
				$file = $data['file'];
			break;
		}

		if (!$method || !$file) {
			return;
		}

		if (isset($data['_id'])) {
			$data += (array) get_object_vars($grid->get($data['_id']));
			$grid->delete($data['_id']);
		}
		unset($data['file']);
		return $grid->{$method}($file, $data);
	}