Method build

parquet/src/arrow/push_decoder/reader_builder/data.rs:181–221

(self)

    }

    pub(crate) fn build(self) -> DataRequest {
        let Self {
            row_group_idx,
            row_count,
            batch_size,
            parquet_metadata,
            projection,
            selection,
            cache_projection,
            column_chunks,
        } = self;

        let row_group_meta_data = parquet_metadata.row_group(row_group_idx);

        // If no previously read column chunks are provided, create a new location to hold them
        let column_chunks =
            column_chunks.unwrap_or_else(|| vec![None; row_group_meta_data.columns().len()]);

        // Create an InMemoryRowGroup to hold the column chunks, this is a
        // temporary structure used to tell the ArrowReaders what pages are
        // needed for decoding
        let row_group = InMemoryRowGroup {
            row_count,
            column_chunks,
            offset_index: get_offset_index(parquet_metadata, row_group_idx),
            row_group_idx,
            metadata: parquet_metadata,
        };

        let FetchRanges {
            ranges,
            page_start_offsets,
        } = row_group.fetch_ranges(projection, selection, batch_size, cache_projection);

        DataRequest {
            // Save any previously read column chunks
            column_chunks: row_group.column_chunks,
            ranges,
            page_start_offsets,
        }
    }
}

fn get_offset_index(