Method on_next_task

cpp/src/arrow/c/bridge.cc:2643–2672

  }

  static int on_next_task(ArrowAsyncDeviceStreamHandler* self, ArrowAsyncTask* task,
                          const char* metadata) {
    auto* private_data = reinterpret_cast<PrivateData*>(self->private_data);

    if (task == nullptr) {
      std::unique_lock<std::mutex> lock(private_data->state_->mutex_);
      private_data->state_->end_of_stream_ = true;
      lock.unlock();
      private_data->state_->cv_.notify_one();
      return 0;
    }

    std::shared_ptr<KeyValueMetadata> kvmetadata;
    if (metadata != nullptr) {
      auto maybe_decoded = DecodeMetadata(metadata);
      if (!maybe_decoded.ok()) {
        private_data->state_->error_ = std::move(maybe_decoded).status();
        private_data->state_->cv_.notify_one();
        return EINVAL;
      }

      kvmetadata = std::move(maybe_decoded->metadata);
    }

    std::unique_lock<std::mutex> lock(private_data->state_->mutex_);
    private_data->state_->batches_.push({*task, std::move(kvmetadata)});
    lock.unlock();
    private_data->state_->cv_.notify_one();
    return 0;
  }

  static void on_error(ArrowAsyncDeviceStreamHandler* self, int code, const char* message,
                       const char* metadata) {