// {
#include <boost/assert.hpp>
#include <iostream>
#include <mutex>
#include <thread>
void long_running_task() {
std::this_thread::sleep_for(std::chrono::milliseconds(100));
}
// }
class SerialPort {
enum class State { Init, Connected, Sending, Receiving };
public:
void connect();
std::string send_request(const std::string& request);
void print_state(std::ostream& os) const;
private:
mutable std::mutex guard_;
State state_ = State::Init;
};
void SerialPort::connect() {
long_running_task();
std::scoped_lock lock{guard_};
BOOST_ASSERT_MSG(state_ == State::Init, "port already connected");
state_ = State::Connected;
}
std::string SerialPort::send_request(const std::string& request) {
{
std::scoped_lock lock{guard_};
BOOST_ASSERT_MSG(state_ == State::Connected, "port not connected yet");
state_ = State::Sending;
}
long_running_task();
{
std::scoped_lock lock{guard_};
BOOST_ASSERT_MSG(state_ == State::Sending, "detected race");
state_ = State::Receiving;
}
long_running_task();
{
std::scoped_lock lock{guard_};
BOOST_ASSERT_MSG(state_ == State::Receiving, "detected race");
state_ = State::Connected;
}
return "ack";
