mpd/src/win32/ComWorker.hxx

88 lines
2.2 KiB
C++

/*
* Copyright 2020-2021 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_WIN32_COM_WORKER_HXX
#define MPD_WIN32_COM_WORKER_HXX
#include "WinEvent.hxx"
#include "thread/Future.hxx"
#include "thread/Thread.hxx"
#include <boost/lockfree/spsc_queue.hpp>
#include <windows.h>
// Worker thread for all COM operation
class COMWorker {
Thread thread{BIND_THIS_METHOD(Work)};
boost::lockfree::spsc_queue<std::function<void()>> spsc_buffer{32};
std::atomic_flag running_flag = true;
WinEvent event{};
public:
COMWorker() {
thread.Start();
}
~COMWorker() noexcept {
Finish();
thread.Join();
}
COMWorker(const COMWorker &) = delete;
COMWorker &operator=(const COMWorker &) = delete;
template<typename Function>
auto Async(Function &&function) {
using R = std::invoke_result_t<std::decay_t<Function>>;
auto promise = std::make_shared<Promise<R>>();
auto future = promise->get_future();
Push([function = std::forward<Function>(function),
promise = std::move(promise)]() mutable {
try {
if constexpr (std::is_void_v<R>) {
std::invoke(std::forward<Function>(function));
promise->set_value();
} else {
promise->set_value(std::invoke(std::forward<Function>(function)));
}
} catch (...) {
promise->set_exception(std::current_exception());
}
});
return future;
}
private:
void Finish() noexcept {
running_flag.clear();
event.Set();
}
void Push(const std::function<void()> &function) {
spsc_buffer.push(function);
event.Set();
}
void Work() noexcept;
};
#endif