void kqueue_reactor::start_op()

in demo_example/asio/asio/detail/impl/kqueue_reactor.ipp [193:263]

• 64 lines of code
• 11 McCabe index (conditional complexity)

void kqueue_reactor::start_op(int op_type, socket_type descriptor,
    kqueue_reactor::per_descriptor_data& descriptor_data, reactor_op* op,
    bool is_continuation, bool allow_speculative)
{
  if (!descriptor_data)
  {
    op->ec_ = asio::error::bad_descriptor;
    post_immediate_completion(op, is_continuation);
    return;
  }

  mutex::scoped_lock descriptor_lock(descriptor_data->mutex_);

  if (descriptor_data->shutdown_)
  {
    post_immediate_completion(op, is_continuation);
    return;
  }

  if (descriptor_data->op_queue_[op_type].empty())
  {
    static const int num_kevents[max_ops] = { 1, 2, 1 };

    if (allow_speculative
        && (op_type != read_op
          || descriptor_data->op_queue_[except_op].empty()))
    {
      if (op->perform())
      {
        descriptor_lock.unlock();
        scheduler_.post_immediate_completion(op, is_continuation);
        return;
      }

      if (descriptor_data->num_kevents_ < num_kevents[op_type])
      {
        struct kevent events[2];
        ASIO_KQUEUE_EV_SET(&events[0], descriptor, EVFILT_READ,
            EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
        ASIO_KQUEUE_EV_SET(&events[1], descriptor, EVFILT_WRITE,
            EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
        if (::kevent(kqueue_fd_, events, num_kevents[op_type], 0, 0, 0) != -1)
        {
          descriptor_data->num_kevents_ = num_kevents[op_type];
        }
        else
        {
          op->ec_ = asio::error_code(errno,
              asio::error::get_system_category());
          scheduler_.post_immediate_completion(op, is_continuation);
          return;
        }
      }
    }
    else
    {
      if (descriptor_data->num_kevents_ < num_kevents[op_type])
        descriptor_data->num_kevents_ = num_kevents[op_type];

      struct kevent events[2];
      ASIO_KQUEUE_EV_SET(&events[0], descriptor, EVFILT_READ,
          EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
      ASIO_KQUEUE_EV_SET(&events[1], descriptor, EVFILT_WRITE,
          EV_ADD | EV_CLEAR, 0, 0, descriptor_data);
      ::kevent(kqueue_fd_, events, descriptor_data->num_kevents_, 0, 0, 0);
    }
  }

  descriptor_data->op_queue_[op_type].push(op);
  scheduler_.work_started();
}