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/*
* Copyright (C) 2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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 APPLE INC. AND ITS 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 APPLE INC. OR ITS 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.
*/
#pragma once
#include <wtf/Expected.h>
namespace WebCore {
enum class CallbackResultType {
Success,
ExceptionThrown,
UnableToExecute
};
template<typename ReturnType> class CallbackResult {
public:
CallbackResult(CallbackResultType);
CallbackResult(ReturnType&&);
CallbackResultType type() const;
ReturnType&& releaseReturnValue();
private:
Expected<ReturnType, CallbackResultType> m_value;
};
template<> class CallbackResult<void> {
public:
CallbackResult() = default;
CallbackResult(CallbackResultType);
CallbackResultType type() const;
private:
CallbackResultType m_type = CallbackResultType::Success;
};
template<typename ReturnType> inline CallbackResult<ReturnType>::CallbackResult(CallbackResultType type)
: m_value(makeUnexpected(type))
{
}
template<typename ReturnType> inline CallbackResult<ReturnType>::CallbackResult(ReturnType&& returnValue)
: m_value(WTFMove(returnValue))
{
}
template<typename ReturnType> inline CallbackResultType CallbackResult<ReturnType>::type() const
{
return m_value.has_value() ? CallbackResultType::Success : m_value.error();
}
template<typename ReturnType> inline auto CallbackResult<ReturnType>::releaseReturnValue() -> ReturnType&&
{
ASSERT(m_value.has_value());
return WTFMove(m_value.value());
}
// Void specialization
inline CallbackResult<void>::CallbackResult(CallbackResultType type)
: m_type(type)
{
}
inline CallbackResultType CallbackResult<void>::type() const
{
return m_type;
}
}
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