Method PollOnce

cpp/src/arrow/acero/sorted_merge_node.cc:543–585

Gets a batch. Returns true if there is more data to process, false if we are done or an error occurred

  /// Gets a batch. Returns true if there is more data to process, false if we
  /// are done or an error occurred
  bool PollOnce() {
    std::lock_guard<std::mutex> guard(gate);
    if (!CheckEnded()) {
      return false;
    }

    // Process batches while we have data
    for (;;) {
      Result<std::shared_ptr<RecordBatch>> result = getNextBatch();

      if (result.ok()) {
        auto out_rb = *result;
        if (!out_rb) {
          break;
        }
        ExecBatch out_b(*out_rb);
        out_b.index = batches_produced++;
        Status st = output_->InputReceived(this, std::move(out_b));
        if (!st.ok()) {
          ARROW_LOG(FATAL) << "Error in output_::InputReceived: " << st.ToString();
          EndFromProcessThread(std::move(st));
        }
      } else {
        EndFromProcessThread(result.status());
        return false;
      }
    }

    // Report to the output the total batch count, if we've already
    // finished everything (there are two places where this can happen:
    // here and InputFinished)
    //
    // It may happen here in cases where InputFinished was called before
    // we were finished producing results (so we didn't know the output
    // size at that time)
    if (!CheckEnded()) {
      return false;
    }

    // There is no more we can do now but there is still work remaining
    // for later when more data arrives.
    return true;
  }

#ifdef ARROW_ENABLE_THREADING
  void EmitBatches() {