so_5/wrapped_env_demo_3/main.cpp

/*
 * An example of use wrapped_env with simple_mtsafe environment
 * and two working threads with mchains and delayed messages.
 */

#include <so_5/all.hpp>

// Messages for exchanges between threads.
struct tick final : public so_5::signal_t {};
struct tack final : public so_5::signal_t {};

// Special signal to stop the exchange.
struct stop final : public so_5::signal_t {};

// Helper class for removing code duplication in handling the state of one
// working thread.
class thread_state final
{
  std::chrono::milliseconds pause_{ 750 };
  bool must_stop_{ false };

public :
  bool must_stop() const { return must_stop_; }

  template<typename Reply>
  void reply_or_stop( const so_5::mchain_t & to )
  {
    if( pause_ > std::chrono::milliseconds(5) )
    {
      pause_ = std::chrono::milliseconds(
          static_cast< decltype(pause_.count()) >(pause_.count() / 1.5) );
      so_5::send_delayed< Reply >( to, pause_ );
    }
    else
    {
      so_5::send< stop >( to );
      must_stop_ = true;
    }
  }
};

// Body for thread.
void thread_body( so_5::mchain_t recv_chain, so_5::mchain_t write_chain )
{
  thread_state state;
  receive(
    from(recv_chain).stop_on( [&state]{ return state.must_stop(); } ),
    [&]( so_5::mhood_t<tick> ) {
      std::cout << "Tick!" << std::endl;
      state.reply_or_stop< tack >( write_chain );
    },
    [&]( so_5::mhood_t<tack> ) {
      std::cout << "Tack!" << std::endl;
      state.reply_or_stop< tick >( write_chain );
    } );
}

// Just a helper function for preparation of environment params.
// It is needed just for shortening of main() function code.
so_5::environment_params_t make_env_params()
{
  so_5::environment_params_t env_params;
  env_params.infrastructure_factory(
      so_5::env_infrastructures::simple_mtsafe::factory() );
  return env_params;
}

int main()
{
  so_5::wrapped_env_t sobj( make_env_params() );

  // An instance for second working thread.
  // The thread itself will be started later.
  std::thread second_thread;
  // This thread must be joined later.
  const auto thread_joiner = so_5::auto_join( second_thread );

  // We need two simple mchains for exchange.
  auto ch1 = create_mchain( sobj );
  auto ch2 = create_mchain( sobj );
  // The chains must be closed automatically.
  const auto ch_closer = so_5::auto_close_drop_content( ch1, ch2 );

  // Launch another thread.
  second_thread = std::thread( thread_body, ch2, ch1 );

  // The first message must be initiated.
  so_5::send< tick >( ch1 );

  // Launch the interchange on the context of main thread.
  thread_body( ch1, ch2 );

  return 0;
}