Method AppendReal

cpp/src/arrow/util/task_group.cc:92–127

  }

  void AppendReal(FnOnce<Status()> task) override {
    DCHECK(!finished_);
    if (stop_token_.IsStopRequested()) {
      UpdateStatus(stop_token_.Poll());
      return;
    }

    // The hot path is unlocked thanks to atomics
    // Only if an error occurs is the lock taken
    if (ok_.load(std::memory_order_acquire)) {
      nremaining_.fetch_add(1, std::memory_order_acquire);

      auto self = checked_pointer_cast<ThreadedTaskGroup>(shared_from_this());

      auto callable = [self = std::move(self), task = std::move(task),
                       stop_token = stop_token_]() mutable {
        if (self->ok_.load(std::memory_order_acquire)) {
          Status st;
          if (stop_token.IsStopRequested()) {
            st = stop_token.Poll();
          } else {
            // XXX what about exceptions?
            st = std::move(task)();
          }
          self->UpdateStatus(std::move(st));
        }
        self->OneTaskDone();
      };
      auto st = executor_->Spawn(std::move(callable));
      bool spawn_successful = st.ok();
      UpdateStatus(std::move(st));
      if (!spawn_successful) {
        OneTaskDone();
      }
    }
  }

  Status current_status() override {
    std::lock_guard<std::mutex> lock(mutex_);