diff options
Diffstat (limited to 'libdevcore/Result.h')
-rw-r--r-- | libdevcore/Result.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/libdevcore/Result.h b/libdevcore/Result.h new file mode 100644 index 00000000..4f7a063b --- /dev/null +++ b/libdevcore/Result.h @@ -0,0 +1,66 @@ +/* + 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; +}; + +} |