| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| **/ |
| |
| #ifndef QUICKSTEP_UTILITY_SCOPED_REASSIGNMENT_HPP_ |
| #define QUICKSTEP_UTILITY_SCOPED_REASSIGNMENT_HPP_ |
| |
| #include <utility> |
| #include <type_traits> |
| |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| |
| /** \addtogroup Utility |
| * @{ |
| */ |
| |
| /** |
| * @brief RAII helper object that assigns a new value to a variable and restores |
| * the old value when the helper object goes out of scope. |
| **/ |
| template <typename T> |
| class ScopedReassignment { |
| public: |
| /** |
| * @brief Constructor. |
| * |
| * @param var The variable. |
| * @param new_value The new value to be assigned to \p var. |
| **/ |
| template <typename U> |
| ScopedReassignment(T *var, U &&new_value) |
| : var_(*var), |
| old_value_(std::move(*var)) { |
| *var = std::forward<U>(new_value); |
| } |
| |
| /** |
| * @brief Destructor. Restores the old value to \p var_. |
| **/ |
| ~ScopedReassignment() { |
| var_ = std::move(old_value_); |
| } |
| |
| /** |
| * @brief Get the old value. |
| * |
| * @return A const reference to the old value. |
| */ |
| inline const T& old_value() const { |
| return old_value_; |
| } |
| |
| private: |
| T &var_; |
| T old_value_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ScopedReassignment); |
| }; |
| |
| /** @} */ |
| |
| } // namespace quickstep |
| |
| #endif // QUICKSTEP_UTILITY_SCOPED_REASSIGNMENT_HPP_ |