ladybird/AK/Result.h
Andreas Kling 4a83a37f79 AK: Add release_value() and release_error() to AK::Result
These are nice when you want to move something out of the result,
and match the API we already have for Optional.
2021-01-09 19:57:50 +01:00

132 lines
3.0 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* 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 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 COPYRIGHT HOLDER 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.
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Optional.h>
namespace AK {
template<typename ValueType, typename ErrorType>
class [[nodiscard]] Result {
public:
Result(const ValueType& res)
: m_result(res)
{
}
Result(ValueType&& res)
: m_result(move(res))
{
}
Result(const ErrorType& error)
: m_error(error)
{
}
Result(ErrorType&& error)
: m_error(move(error))
{
}
Result(Result&& other) = default;
Result(const Result& other) = default;
~Result() = default;
ValueType& value()
{
return m_result.value();
}
ErrorType& error()
{
return m_error.value();
}
bool is_error() const
{
return m_error.has_value();
}
ValueType release_value()
{
return m_result.release_value();
}
ErrorType release_error()
{
return m_error.release_value();
}
private:
Optional<ValueType> m_result;
Optional<ErrorType> m_error;
};
// Partial specialization for void value type
template<typename ErrorType>
class [[nodiscard]] Result<void, ErrorType> {
public:
Result(const ErrorType& error)
: m_error(error)
{
}
Result(ErrorType&& error)
: m_error(move(error))
{
}
Result() = default;
Result(Result&& other) = default;
Result(const Result& other) = default;
~Result() = default;
ErrorType& error()
{
return m_error.value();
}
bool is_error() const
{
return m_error.has_value();
}
void release_error()
{
return m_error.release_value();
}
private:
Optional<ErrorType> m_error;
};
}
using AK::Result;