1 //===- llvm/ADT/ScopeExit.h - Execute code at scope exit --------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// 9 /// \file 10 /// This file defines the make_scope_exit function, which executes user-defined 11 /// cleanup logic at scope exit. 12 /// 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ADT_SCOPEEXIT_H 16 #define LLVM_ADT_SCOPEEXIT_H 17 18 #include "llvm/Support/Compiler.h" 19 20 #include <type_traits> 21 #include <utility> 22 23 namespace llvm { 24 namespace detail { 25 26 template <typename Callable> class scope_exit { 27 Callable ExitFunction; 28 bool Engaged = true; // False once moved-from or release()d. 29 30 public: 31 template <typename Fp> scope_exit(Fp && F)32 explicit scope_exit(Fp &&F) : ExitFunction(std::forward<Fp>(F)) {} 33 scope_exit(scope_exit && Rhs)34 scope_exit(scope_exit &&Rhs) 35 : ExitFunction(std::move(Rhs.ExitFunction)), Engaged(Rhs.Engaged) { 36 Rhs.release(); 37 } 38 scope_exit(const scope_exit &) = delete; 39 scope_exit &operator=(scope_exit &&) = delete; 40 scope_exit &operator=(const scope_exit &) = delete; 41 release()42 void release() { Engaged = false; } 43 ~scope_exit()44 ~scope_exit() { 45 if (Engaged) 46 ExitFunction(); 47 } 48 }; 49 50 } // end namespace detail 51 52 // Keeps the callable object that is passed in, and execute it at the 53 // destruction of the returned object (usually at the scope exit where the 54 // returned object is kept). 55 // 56 // Interface is specified by p0052r2. 57 template <typename Callable> 58 [[nodiscard]] detail::scope_exit<std::decay_t<Callable>> make_scope_exit(Callable && F)59make_scope_exit(Callable &&F) { 60 return detail::scope_exit<std::decay_t<Callable>>(std::forward<Callable>(F)); 61 } 62 63 } // end namespace llvm 64 65 #endif 66