OpenLCP/protocol/esta/sacn/universesender.cpp

/*
  universesender.cpp

  Copyright (c) 2020 Kevin Matz (kevin.matz@gmail.com)

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
#include "universesender.h"
#include "universe.h"

namespace sACN {

/**
 * @brief UniverseSender::UniverseSender
 * @param universe
 */
UniverseSender::UniverseSender(Universe * universe)
    : mUniverse(universe)
    , terminated_resend(3)
    , minimum_update_time(22700)
    , last_null_data({0})
    , retransmission_count(0)
    , keep_alive_interval(800)
    , enable_(true)
    , worker_(&UniverseSender::loop_, this)
{
}


/**
 * @brief UniverseSender::~UniverseSender
 */
UniverseSender::~UniverseSender()
{
  if (isSending())
    {
      kill();
      worker_.join();
    }
}


/**
 * @brief UniverseSender::isSending
 * @return
 */
bool UniverseSender::isSending()
{
  return (worker_.joinable());
}


/**
 * @brief UniverseSender::flush
 */
void UniverseSender::flush()
{
  request_.notify_all();
}


/**
 * @brief UniverseSender::kill
 */
void UniverseSender::kill()
{
  control_mutex_.lock();
  enable_ = false;
  control_mutex_.unlock();
  flush();
}


/**
 * @brief UniverseSender::loop_
 */
void UniverseSender::loop_()
{
  bool enabled = true; // at least 1 loop
  bool new_data;
  std::chrono::nanoseconds elapsed;
  std::chrono::microseconds sleep;
  std::mutex mtx; // std::conditional_variable requires in the sleeping thread.  Why??

  while (enabled || terminated_resend > 0)
    {
      // enforce strict minimum update times
      elapsed = std::chrono::system_clock::now() - mUniverse->last_updated_;
      if (elapsed < minimum_update_time)
        std::this_thread::sleep_for(minimum_update_time - elapsed);

      // check for control permission to continue looping
      control_mutex_.lock();
      enabled = enable_;
      control_mutex_.unlock();

      if (enable_)
        {
          mUniverse->setStatus(Universe::DMX_ACTIVE);
          mUniverse->null_start_mutex.lock();
          new_data = (mUniverse->null_start_data != last_null_data);
          if (new_data)
            {
              last_null_data = mUniverse->null_start_data;
              retransmission_count = 0;
            }
          mUniverse->null_start_mutex.unlock();
          if (++retransmission_count > 3)
            {
              retransmission_count = 3;         // prevent counter from overflowing
              sleep = keep_alive_interval;
            }
          else
            sleep = minimum_update_time;
        }
      else
        {
          mUniverse->setStatus(Universe::sACN_TERMINATED);  // note the changed operating status
          mUniverse->metadata_->options.stream_terminated = true; // set the stream_terminated bit
          --terminated_resend;         // stream_terminated must be sent 3 times
          sleep = minimum_update_time; // stay throttled up through the termination sequence
        }

      // send the sACN message
      mUniverse->sendDMP(mUniverse->as_DMP_());
      mUniverse->last_updated_ = std::chrono::system_clock::now();
      /// > \cite sACN 6.2.5 E1.31 Data Packet: Sequence Number
      /// >
      /// > ... The sequence number for a universe shall be incremented by one for
      /// > every packet sent on that universe...
      mUniverse->metadata_->sequence_number++;

      // sleep before the next cycle
      request_.wait_for(mtx, sleep);
    }
}


} // namespace sACN