/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            syncedsettings.h
 *
 *  Thu Mar 31 09:23:27 CEST 2016
 *  Copyright 2016 Christian Gl�ckner
 *  cgloeckner@freenet.de
 ****************************************************************************/

/*
 *  This file is part of DrumGizmo.
 *
 *  DrumGizmo is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  DrumGizmo 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with DrumGizmo; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#pragma once

#include <mutex>

// type trait helper

template <typename T, typename... Types>
struct pack_contains;

template <typename T, typename... Types>
struct pack_contains<T, T, Types...>
	: std::true_type {
};

template <typename T, typename Head, typename... Types>
struct pack_contains<T, Head, Types...>
	: pack_contains<T, Types...> {
};

template <typename T>
struct pack_contains<T>
	: std::false_type {
};

// --------------------------------------------------------------------

template <typename T>
class Group;

template <typename T>
class Accessor {
	private:
		std::lock_guard<std::mutex> lock;
		
	public:
		Accessor(Group<T>& parent)
			: lock{parent.mutex}
			, data{parent.data} {
		}
		
		T& data;
};

template <typename T>
class Group {
	private:
		friend class Accessor<T>;
		
		mutable std::mutex mutex;
		T data;
		
	public:
		Group()
			: mutex{}
			,  data{} {
		}
		
		Group(T const & data)
			: mutex{}
			, data{data} {
		}
		
		Group(T&& data)
			: mutex{}
			, data{std::move(data)} {
		}
		
		Group(Group<T> const & other)
			: mutex{}
			, data{} {
			std::lock_guard<std::mutex> lock{other.mutex};
			data = other.data;
		}
		
		Group(Group<T>&& other)
			: mutex{}
			, data{} {
			std::lock_guard<std::mutex> lock{other.mutex};
			std::swap(data, other.data);
		}
		
		operator T() const {
			std::lock_guard<std::mutex> lock{mutex};
			return data;
		}
};