defer pr.closedMu.Unlock()
	if pr.closed {
		return nil
	}
	pr.closed = true
	if pr.closer != nil {
		pr.closer.Close()
	}
	return pr.rc.Close()
}

func (pr *progressReader) Stats() (bytesScanned, bytesProcessed int64) {
	if pr == nil {
		return 0, 0
	}
	return pr.scannedReader.BytesRead(), pr.processedReader.BytesRead()
}

func newProgressReader(rc io.ReadCloser, compType CompressionType) (*progressReader, error) {

	case jsonFormat:
		return json.NewRecord(sql.SelectFmtJSON)
	}

	panic(fmt.Errorf("unknown output format '%v'", s3Select.Output.format))
}

func (s3Select *S3Select) getProgress() (bytesScanned, bytesProcessed int64) {
	if s3Select.progressReader != nil {
		return s3Select.progressReader.Stats()
	}

	return -1, -1
}

// Open - opens S3 object by using callback for SQL selection query.