Method ToTableAsync

cpp/src/arrow/dataset/scanner.cc:711–733

}

Future<std::shared_ptr<Table>> AsyncScanner::ToTableAsync(Executor* cpu_executor) {
  auto scan_options = scan_options_;
  ARROW_ASSIGN_OR_RAISE(
      auto positioned_batch_gen,
      ScanBatchesUnorderedAsync(cpu_executor, /*sequence_fragments=*/false,
                                /*use_legacy_batching=*/true));
  /// Wraps the state in a shared_ptr to ensure that failing ScanTasks don't
  /// invalidate concurrently running tasks when Finish() early returns
  /// and the mutex/batches fail out of scope.
  auto state = std::make_shared<AsyncTableAssemblyState>();

  auto table_building_task = [state](const EnumeratedRecordBatch& batch) {
    state->Emplace(batch);
    return batch;
  };

  auto table_building_gen =
      MakeMappedGenerator(positioned_batch_gen, table_building_task);

  return DiscardAllFromAsyncGenerator(table_building_gen).Then([state, scan_options]() {
    return Table::FromRecordBatches(scan_options->projected_schema, state->Finish());
  });
}

Future<int64_t> AsyncScanner::CountRowsAsync(Executor* executor) {
  ARROW_ASSIGN_OR_RAISE(auto fragment_gen, GetFragments());