Class task_wait_handle

3rdparty/asyncplusplus/include/async++/scheduler.h:33–82

Task handle used by a wait handler

// Task handle used by a wait handler
class task_wait_handle {
	detail::task_base* handle;

	// Allow construction in wait_for_task()
	friend LIBASYNC_EXPORT void detail::wait_for_task(detail::task_base* t);
	task_wait_handle(detail::task_base* t)
		: handle(t) {}

	// Execution function for use by wait handlers
	template<typename Func>
	struct wait_exec_func: private detail::func_base<Func> {
		template<typename F>
		explicit wait_exec_func(F&& f)
			: detail::func_base<Func>(std::forward<F>(f)) {}
		void operator()(detail::task_base*)
		{
			// Just call the function directly, all this wrapper does is remove
			// the task_base* parameter.
			this->get_func()();
		}
	};

public:
	task_wait_handle()
		: handle(nullptr) {}

	// Check if the handle is valid
	explicit operator bool() const
	{
		return handle != nullptr;
	}

	// Check if the task has finished executing
	bool ready() const
	{
		return detail::is_finished(handle->state.load(std::memory_order_acquire));
	}

	// Queue a function to be executed when the task has finished executing.
	template<typename Func>
	void on_finish(Func&& func)
	{
		// Make sure the function type is callable
		static_assert(detail::is_callable<Func()>::value, "Invalid function type passed to on_finish()");

		auto cont = new detail::task_func<typename std::remove_reference<decltype(inline_scheduler())>::type, wait_exec_func<typename std::decay<Func>::type>, detail::fake_void>(std::forward<Func>(func));
		cont->sched = std::addressof(inline_scheduler());
		handle->add_continuation(inline_scheduler(), detail::task_ptr(cont));
	}
};

// Wait handler function prototype
typedef void (*wait_handler)(task_wait_handle t);