Task.hh

#ifndef VTESTBED_GUI_TASK_HH
#define VTESTBED_GUI_TASK_HH

#include <atomic>
#include <exception>
#include <thread>

namespace vtb {

    namespace gui {

        class Task {

        private:
            enum class State {
                Initial,
                Running,
                Finished
            };

        private:
            std::thread _thread;
            std::exception_ptr _exception;
            std::atomic<State> _state{State::Initial};

        public:

            Task() = default;

            template <class Function>
            inline void
            run(Function function) {
                this->_state = State::Running;
                this->_thread = std::thread{
                    [function,this] () {
                        try {
                            function();
                            this->_exception = nullptr;
                        } catch (...) {
                            this->_exception = std::current_exception();
                        }
                        this->_state = State::Finished;
                    }
                };
            }

            inline bool
            initial() const {
                return this->_state == State::Initial;
            }

            inline bool
            finished() const {
                return this->_state == State::Finished;
            }

            inline bool
            running() const {
                return this->_state == State::Running;
            }

            inline void
            wait() {
                if (this->_thread.joinable()) {
                    this->_thread.join();
                }
                auto ptr = this->_exception;
                clear();
                if (ptr) {
                    std::rethrow_exception(ptr);
                }
            }

            inline void
            clear() {
                this->_exception = nullptr;
                this->_state = State::Initial;
            }

        };

    }

}

#endif // vim:filetype=cpp