ClickHouse/dbms/src/Processors/Formats/Impl/ORCBlockInputFormat.cpp

#include "ORCBlockInputFormat.h"
#if USE_ORC

#include <Formats/FormatFactory.h>
#include <IO/BufferBase.h>
#include <IO/ReadBufferFromMemory.h>
#include <IO/WriteBufferFromString.h>
#include <IO/WriteHelpers.h>
#include <IO/copyData.h>
#include <arrow/io/memory.h>
#include "ArrowColumnToCHColumn.h"

namespace DB
{
    ORCBlockInputFormat::ORCBlockInputFormat(ReadBuffer &in_, Block header_, const Context &context_)
            : IInputFormat(std::move(header_), in_), context{context_} {
    }

    Chunk ORCBlockInputFormat::generate()
    {
        Chunk res;

        auto &header = getPort().getHeader();

        if (!in.eof())
        {
            if (row_group_current < row_group_total)
                throw Exception{"Got new data, but data from previous chunks was not read " +
                                std::to_string(row_group_current) + "/" + std::to_string(row_group_total),
                                ErrorCodes::CANNOT_READ_ALL_DATA};

            file_data.clear();
            {
                WriteBufferFromString file_buffer(file_data);
                copyData(in, file_buffer);
            }

            std::unique_ptr<arrow::Buffer> local_buffer = std::make_unique<arrow::Buffer>(file_data);


            std::shared_ptr<arrow::io::RandomAccessFile> in_stream(new arrow::io::BufferReader(*local_buffer));

            bool ok = arrow::adapters::orc::ORCFileReader::Open(in_stream, arrow::default_memory_pool(),
                                                                &file_reader).ok();
            if (!ok)
                return res;

            row_group_total = file_reader->NumberOfRows();
            row_group_current = 0;

        } else
            return res;

        if (row_group_current >= row_group_total)
            return res;
        std::shared_ptr<arrow::Table> table;

        arrow::Status read_status = file_reader->Read(&table);

        ArrowColumnToCHColumn::arrowTableToCHChunk(res, table, read_status, header, row_group_current, context, "ORC");

        return res;
    }

    void ORCBlockInputFormat::resetParser()
    {
        IInputFormat::resetParser();

        file_reader.reset();
        file_data.clear();
        row_group_total = 0;
        row_group_current = 0;
    }

    void registerInputFormatProcessorORC(FormatFactory &factory)
    {
        factory.registerInputFormatProcessor(
                "ORC",
                [](ReadBuffer &buf,
                   const Block &sample,
                   const Context &context,
                   const RowInputFormatParams &,
                   const FormatSettings & /* settings */)
                   {
                    return std::make_shared<ORCBlockInputFormat>(buf, sample, context);
                });
    }

}
#else

namespace DB
{
    class FormatFactory;
    void registerInputFormatProcessorORC(FormatFactory &)
    {
    }
}

#endif