boost.asio and custom coroutines experiment

main.cpp

#include <vector>
#include <iostream>
#include <future>
#include <boost/optional.hpp>
#include <boost/filesystem.hpp>
#include <boost/thread.hpp>
#include <boost/asio.hpp>
#include <boost/asio/use_future.hpp>
#include <boost/asio/spawn.hpp>
struct scheduler
	: boost::asio::io_service::service
{
	static boost::asio::io_service::id id;
	boost::asio::io_service io_service_tasks;
	boost::optional<boost::asio::io_service::work> io_service_work;
	boost::thread tasks_thread;
	scheduler(boost::asio::io_service & io_service)
		: boost::asio::io_service::service(io_service)
		, io_service_tasks()
	{
	}
	void shutdown_service()
	{
		io_service_work.reset();
		tasks_thread.join();
	}
	void start()
	{
		io_service_work = boost::in_place(boost::ref(io_service_tasks));
		tasks_thread = boost::thread(boost::bind(&scheduler::thread_func, this));
	}
	void thread_func()
	{
		std::cout << "start scheduler" << std::endl;
		std::size_t total = io_service_tasks.run();
		std::cout << "stop scheduler total tasks " << total << std::endl;
	}
	template <typename T>
	struct async_callback
	{
		T t_;
		async_callback(T t) : t_(t) {}
		void operator()(const boost::system::error_code & ec)
		{
			t_(ec);
		}
	};
	template <typename Op, typename Callback>
	void schedule(Op op, boost::asio::basic_yield_context<Callback> callback)
	{
		io_service_tasks.post(
			[=]()
			{
				std::cout << "schedule work in background..." << std::endl;
				boost::system::error_code ec;
				//op(ec);
				std::cout << "scheduled work is done..." << std::endl;
				//callback(ec);
				//this->get_io_service().post(boost::bind(callback, ec));
			});
	}
};
boost::asio::io_service::id scheduler::id;

void handler(boost::asio::io_service & io_service,
	boost::asio::yield_context yield)
{
	boost::system::error_code ec;
	boost::asio::use_service<scheduler>(io_service)
		.schedule([](boost::system::error_code & ec) { boost::filesystem::create_directories("/tmp/boostfs", ec); }, yield[ec]);
	std::cout << "handler done" << std::endl;
//	boost::system::error_code ec;
//	boost::asio::deadline_timer timer(io_service);
//	timer.expires_from_now(boost::posix_time::seconds(1));
}

int
main()
{
	boost::asio::io_service io_service;
	boost::asio::use_service<scheduler>(io_service).start();
  boost::asio::spawn(io_service,
		boost::bind(&handler, boost::ref(io_service), _1));
	io_service.run();
}