Source/WebCore/dom/ExceptionOr.h

/*

Copyright (C) 2016 Apple Inc. All rights reserved.

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are met:
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    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.

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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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*/

#pragma once

#include "Exception.h"
#include <wtf/Variant.h>

namespace WebCore {

template<typename ReturnType> class ExceptionOr {
public:
    ExceptionOr(Exception&&);
    ExceptionOr(ReturnType&&);

    bool hasException() const;
    ExceptionCode exceptionCode() const;
    ReturnType&& takeReturnValue();

private:
    std::experimental::variant<Exception, ReturnType> m_value;
};

template<typename ReturnType> inline ExceptionOr<ReturnType>::ExceptionOr(Exception&& exception)
    : m_value(WTFMove(exception))
{
}

template<typename ReturnType> inline ExceptionOr<ReturnType>::ExceptionOr(ReturnType&& returnValue)
    : m_value(WTFMove(returnValue))
{
}

template<typename ReturnType> inline bool ExceptionOr<ReturnType>::hasException() const
{
    return std::experimental::holds_alternative<Exception>(m_value);
}

template<typename ReturnType> inline ExceptionCode ExceptionOr<ReturnType>::exceptionCode() const
{
    return std::experimental::get<Exception>(m_value).code();
}

template<typename ReturnType> inline ReturnType&& ExceptionOr<ReturnType>::takeReturnValue()
{
    return std::experimental::get<ReturnType>(WTFMove(m_value));
}

}