/*
 * Copyright (C) 2016 Max Kellermann <max@duempel.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the
 * distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef BOUND_METHOD_HXX
#define BOUND_METHOD_HXX

#include <utility>

/**
 * This class can invoke a method of a given object.  To do this, it
 * stores a pointer to the member function and a reference to the
 * object.
 *
 * This is a utility to build callbacks.
 *
 * @param T the class whose method is going to be invoked
 * @param R the method's return type
 * @param Args argument types
 */
template<typename T, typename R, typename... Args>
class BoundMethod final {
	T &instance;
	R (T::*method)(Args... args);

public:
	explicit constexpr BoundMethod(T &_instance,
				       R (T::*_method)(Args... args))
		:instance(_instance), method(_method) {}

	template<typename... Args2>
	R operator()(Args2&&... args) {
		return (instance.*method)(std::forward<Args2>(args)...);
	}
};

#endif