presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/storage/OrcStorageManager.java/OrcStorageManager/getColumnInfo
class OrcStorageManager:    private List<ColumnInfo> getColumnInfo(OrcReader reader)
    {
        Optional<OrcFileMetadata> metadata = getOrcFileMetadata(reader);
        if (metadata.isPresent()) {
            return getColumnInfoFromOrcUserMetadata(metadata.get());
        }

        // support for legacy files without metadata
        return getColumnInfoFromOrcColumnTypes(reader.getColumnNames(), reader.getFooter().getTypes());
    }