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 23namespace llvm { 24namespace detail { 25 26template <typename Callable> class scope_exit { 27 Callable ExitFunction; 28 bool Engaged = true; // False once moved-from or release()d. 29 30public: 31 template <typename Fp> 32 explicit scope_exit(Fp &&F) : ExitFunction(std::forward<Fp>(F)) {} 33 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 42 void release() { Engaged = false; } 43 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. 57template <typename Callable> 58[[nodiscard]] detail::scope_exit<std::decay_t<Callable>> 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