Method reader_tree

parquet/src/record/reader.rs:106–326

Builds tree of readers for the current schema recursively.

(
        &self,
        field: TypePtr,
        path: &mut Vec<String>,
        mut curr_def_level: i16,
        mut curr_rep_level: i16,
        paths: &HashMap<ColumnPath, usize>,
        row_group

    /// Builds tree of readers for the current schema recursively.
    fn reader_tree(
        &self,
        field: TypePtr,
        path: &mut Vec<String>,
        mut curr_def_level: i16,
        mut curr_rep_level: i16,
        paths: &HashMap<ColumnPath, usize>,
        row_group_reader: &dyn RowGroupReader,
    ) -> Result<Reader> {
        assert!(field.get_basic_info().has_repetition());
        // Update current definition and repetition levels for this type
        let repetition = field.get_basic_info().repetition();
        match repetition {
            Repetition::OPTIONAL => {
                curr_def_level += 1;
            }
            Repetition::REPEATED => {
                curr_def_level += 1;
                curr_rep_level += 1;
            }
            _ => {}
        }

        path.push(String::from(field.name()));
        let reader = if field.is_primitive() {
            let col_path = ColumnPath::new(path.to_vec());
            let orig_index = *paths
                .get(&col_path)
                .ok_or(general_err!("Path {:?} not found", col_path))?;
            let col_descr = row_group_reader
                .metadata()
                .column(orig_index)
                .column_descr_ptr();
            let col_reader = row_group_reader.get_column_reader(orig_index)?;
            let column = TripletIter::new(col_descr, col_reader, self.batch_size);
            let reader = Reader::PrimitiveReader(field.clone(), Box::new(column));
            if repetition == Repetition::REPEATED {
                Reader::RepeatedReader(
                    field,
                    curr_def_level - 1,
                    curr_rep_level - 1,
                    Box::new(reader),
                )
            } else {
                reader
            }
        } else {
            match field.get_basic_info().converted_type() {
                // List types
                ConvertedType::LIST => {
                    assert_eq!(field.get_fields().len(), 1, "Invalid list type {field:?}");

                    let repeated_field = field.get_fields()[0].clone();
                    assert_eq!(
                        repeated_field.get_basic_info().repetition(),
                        Repetition::REPEATED,
                        "Invalid list type {field:?}"
                    );