1 // Copyright 2021 The Tint Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef SRC_UTILS_DEFER_H_ 16 #define SRC_UTILS_DEFER_H_ 17 18 #include <utility> 19 20 #include "src/utils/concat.h" 21 22 namespace tint { 23 namespace utils { 24 25 /// Defer executes a function or function like object when it is destructed. 26 template <typename F> 27 class Defer { 28 public: 29 /// Constructor 30 /// @param f the function to call when the Defer is destructed Defer(F && f)31 explicit Defer(F&& f) : f_(std::move(f)) {} 32 33 /// Move constructor 34 Defer(Defer&&) = default; 35 36 /// Destructor 37 /// Calls the deferred function ~Defer()38 ~Defer() { f_(); } 39 40 private: 41 Defer(const Defer&) = delete; 42 Defer& operator=(const Defer&) = delete; 43 44 F f_; 45 }; 46 47 /// Constructor 48 /// @param f the function to call when the Defer is destructed 49 template <typename F> MakeDefer(F && f)50inline Defer<F> MakeDefer(F&& f) { 51 return Defer<F>(std::forward<F>(f)); 52 } 53 54 } // namespace utils 55 } // namespace tint 56 57 /// TINT_DEFER(S) executes the statement(s) `S` when exiting the current lexical 58 /// scope. 59 #define TINT_DEFER(S) \ 60 auto TINT_CONCAT(tint_defer_, __COUNTER__) = \ 61 ::tint::utils::MakeDefer([&] { S; }) 62 63 #endif // SRC_UTILS_DEFER_H_ 64