| // Copyright 2019 The Marl Authors. |
| // |
| // Licensed 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 |
| // |
| // https://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. |
| |
| // Finally can be used to execute a lambda or function when the final reference |
| // to the Finally is dropped. |
| // |
| // The purpose of a finally is to perform cleanup or termination logic and is |
| // especially useful when there are multiple early returns within a function. |
| // |
| // A moveable Finally can be constructed with marl::make_finally(). |
| // A sharable Finally can be constructed with marl::make_shared_finally(). |
| |
| #ifndef marl_finally_h |
| #define marl_finally_h |
| |
| #include "export.h" |
| |
| #include <functional> |
| #include <memory> |
| #include <utility> |
| |
| namespace marl { |
| |
| // Finally is a pure virtual base class, implemented by the templated |
| // FinallyImpl. |
| class Finally { |
| public: |
| virtual ~Finally() = default; |
| }; |
| |
| // FinallyImpl implements a Finally. |
| // The template parameter F is the function type to be called when the finally |
| // is destructed. F must have the signature void(). |
| template <typename F> |
| class FinallyImpl : public Finally { |
| public: |
| MARL_NO_EXPORT inline FinallyImpl(const F& func); |
| MARL_NO_EXPORT inline FinallyImpl(F&& func); |
| MARL_NO_EXPORT inline FinallyImpl(FinallyImpl<F>&& other); |
| MARL_NO_EXPORT inline ~FinallyImpl(); |
| |
| private: |
| FinallyImpl(const FinallyImpl<F>& other) = delete; |
| FinallyImpl<F>& operator=(const FinallyImpl<F>& other) = delete; |
| FinallyImpl<F>& operator=(FinallyImpl<F>&&) = delete; |
| F func; |
| bool valid = true; |
| }; |
| |
| template <typename F> |
| FinallyImpl<F>::FinallyImpl(const F& func_) : func(func_) {} |
| |
| template <typename F> |
| FinallyImpl<F>::FinallyImpl(F&& func_) : func(std::move(func_)) {} |
| |
| template <typename F> |
| FinallyImpl<F>::FinallyImpl(FinallyImpl<F>&& other) |
| : func(std::move(other.func)) { |
| other.valid = false; |
| } |
| |
| template <typename F> |
| FinallyImpl<F>::~FinallyImpl() { |
| if (valid) { |
| func(); |
| } |
| } |
| |
| template <typename F> |
| inline FinallyImpl<F> make_finally(F&& f) { |
| return FinallyImpl<F>(std::forward<F>(f)); |
| } |
| |
| template <typename F> |
| inline std::shared_ptr<Finally> make_shared_finally(F&& f) { |
| return std::make_shared<FinallyImpl<F>>(std::forward<F>(f)); |
| } |
| |
| } // namespace marl |
| |
| #endif // marl_finally_h |