Method OpenAsync

cpp/src/parquet/file_reader.cc:793–818

}

Future<std::unique_ptr<ParquetFileReader::Contents>>
ParquetFileReader::Contents::OpenAsync(std::shared_ptr<ArrowInputFile> source,
                                       const ReaderProperties& props,
                                       std::shared_ptr<FileMetaData> metadata) {
  BEGIN_PARQUET_CATCH_EXCEPTIONS
  std::unique_ptr<ParquetFileReader::Contents> result(
      new SerializedFile(std::move(source), props));
  SerializedFile* file = static_cast<SerializedFile*>(result.get());
  if (metadata == nullptr) {
    // TODO(ARROW-12259): workaround since we have Future<(move-only type)>
    struct {
      Result<std::unique_ptr<ParquetFileReader::Contents>> operator()() {
        return std::move(result);
      }

      std::unique_ptr<ParquetFileReader::Contents> result;
    } Continuation;
    Continuation.result = std::move(result);
    return file->ParseMetaDataAsync().Then(std::move(Continuation));
  } else {
    file->set_metadata(std::move(metadata));
    return Future<std::unique_ptr<ParquetFileReader::Contents>>::MakeFinished(
        std::move(result));
  }
  END_PARQUET_CATCH_EXCEPTIONS
}

std::unique_ptr<ParquetFileReader> ParquetFileReader::Open(
    std::shared_ptr<::arrow::io::RandomAccessFile> source, const ReaderProperties& props,