////////////////////////////////////////////////////////////////////////////////////////
//
//  Copyright 2026 OVITO GmbH, Germany
//
//  This file is part of OVITO (Open Visualization Tool).
//
//  OVITO is free software; you can redistribute it and/or modify it either under the
//  terms of the GNU General Public License version 3 as published by the Free Software
//  Foundation (the "GPL") or, at your option, under the terms of the MIT License.
//  If you do not alter this notice, a recipient may use your version of this
//  file under either the GPL or the MIT License.
//
//  You should have received a copy of the GPL along with this program in a
//  file LICENSE.GPL.txt.  You should have received a copy of the MIT License along
//  with this program in a file LICENSE.MIT.txt
//
//  This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND,
//  either express or implied. See the GPL or the MIT License for the specific language
//  governing rights and limitations.
//
////////////////////////////////////////////////////////////////////////////////////////

#pragma once


#include <ovito/core/Core.h>
#include "SharedFuture.h"

namespace Ovito {

/**
 * A weak reference to a SharedFuture
 */
template<typename R>
class WeakSharedFuture : private std::weak_ptr<Task>
{
public:

#ifndef Q_CC_MSVC
    constexpr WeakSharedFuture() noexcept = default;
#else
    constexpr WeakSharedFuture() noexcept : std::weak_ptr<Task>() {}
#endif

    WeakSharedFuture(const SharedFuture<R>& future) noexcept : std::weak_ptr<Task>(future.task()) {}

    WeakSharedFuture& operator=(const SharedFuture<R>& f) noexcept {
        std::weak_ptr<Task>::operator=(f.task());
        return *this;
    }

    void reset() noexcept {
        std::weak_ptr<Task>::reset();
    }

    SharedFuture<R> lock() const noexcept {
        return SharedFuture<R>(std::weak_ptr<Task>::lock());
    }

    bool expired() const noexcept {
        return std::weak_ptr<Task>::expired();
    }
};

}   // End of namespace
