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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <string>
namespace dev
{
/// Simple generic result that holds a value and an optional error message.
/// Results can be implicitly converted to and created from the type of
/// the value they hold. The class is mainly designed for a result type of
/// bool or pointer type. The idea is that the default constructed value of
/// the result type is interpreted as an error value.
///
/// Result<bool> check()
/// {
/// if (false)
/// return Result<bool>("Error message.")
/// return true;
/// }
///
template <class ResultType>
class Result
{
public:
Result(ResultType _value): Result(_value, std::string{}) {}
Result(std::string _message): Result(ResultType{}, std::move(_message)) {}
/// @{
/// @name Wrapper functions
/// Wrapper functions that provide implicit conversions to and explicit retrieval of
/// the value this result holds.
operator ResultType const&() const { return m_value; }
ResultType const& get() const { return m_value; }
/// @}
/// @returns the error message (can be empty).
std::string const& message() const { return m_message; }
private:
explicit Result(ResultType _value, std::string _message):
m_value(std::move(_value)),
m_message(std::move(_message))
{}
ResultType m_value;
std::string m_message;
};
}
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