mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
87 lines
2.6 KiB
C++
87 lines
2.6 KiB
C++
/*
|
|
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/>.
|
|
*/
|
|
// SPDX-License-Identifier: GPL-3.0
|
|
#pragma once
|
|
|
|
#include <string>
|
|
|
|
namespace solidity::util
|
|
{
|
|
|
|
/// 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>::err("Error message.")
|
|
/// return true;
|
|
/// }
|
|
///
|
|
|
|
template <class ResultType>
|
|
class [[nodiscard]] Result
|
|
{
|
|
public:
|
|
/// Constructs a result with _value and an empty message.
|
|
/// This is meant to be called with valid results. Please use
|
|
/// the static err() member function to signal an error.
|
|
Result(ResultType _value): Result(_value, std::string{}) {}
|
|
|
|
/// Constructs a result with a default-constructed value and an
|
|
/// error message.
|
|
static Result<ResultType> err(std::string _message)
|
|
{
|
|
return 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; }
|
|
|
|
/// Merges _other into this using the _merger
|
|
/// and appends the error messages. Meant to be called
|
|
/// with logical operators like logical_and, etc.
|
|
template<typename F>
|
|
void merge(Result<ResultType> const& _other, F _merger)
|
|
{
|
|
m_value = _merger(m_value, _other.get());
|
|
m_message += _other.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;
|
|
};
|
|
|
|
}
|