mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
84 lines
2.5 KiB
C++
84 lines
2.5 KiB
C++
/*
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This file is part of solidity.
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solidity is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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solidity is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with solidity. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <string>
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namespace dev
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{
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/// Simple generic result that holds a value and an optional error message.
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/// Results can be implicitly converted to and created from the type of
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/// the value they hold.
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///
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/// Result<bool> check()
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/// {
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/// if (false)
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/// return Result<bool>(false, "Error message.")
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/// return true;
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/// }
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///
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/// A result can also be instantiated using one of the factory methods it provides:
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///
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/// using BoolResult = Result<bool>;
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/// BoolResult check()
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/// {
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/// if (false)
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/// return BoolResult::failure("Error message");
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/// return BoolResult::success(true);
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/// }
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///
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///
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struct ResultError { std::string reason; };
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template <class ResultType>
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class Result
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{
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public:
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/// @{
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/// @name Factory functions
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/// Factory functions that provide a verbose way to create a result
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static Result<ResultType> Ok(ResultType _value) { return Result(std::move(_value)); }
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static Result<ResultType> Err() { return Result(ResultError{std::string()}); }
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static Result<ResultType> Err(std::string _error) { return Result(ResultError{std::move(_error)}); }
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/// @}
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Result(ResultType _value): m_value(std::move(_value)) {}
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Result(ResultError _error): m_error(std::move(_error.reason)) {}
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Result(ResultType _value, ResultError _error): m_value(std::move(_value)), m_error(std::move(_error.reason)) {}
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/// @{
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/// @name Wrapper functions
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/// Wrapper functions that provide implicit conversions to and explicit retrieval of
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/// the value this result holds.
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/// If the result is an error, accessing the value results in undefined behaviour.
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operator ResultType const&() const { return m_value; }
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ResultType& operator*() const { return m_value; }
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ResultType const& get() const { return m_value; }
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ResultType& get() { return m_value; }
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/// @}
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/// @returns the error message (can be empty).
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std::string const& err() const { return m_error; }
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private:
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ResultType m_value;
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std::string m_error;
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};
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}
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