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// This file defines the make_scope_exit function, which executes user-defined 10// cleanup logic at scope exit. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_ADT_SCOPE_EXIT_H 15#define LLVM_ADT_SCOPE_EXIT_H 16 17#include "llvm/Support/Compiler.h" 18 19#include <type_traits> 20#include <utility> 21 22namespace llvm { 23namespace detail { 24 25template <typename Callable> class scope_exit { 26 Callable ExitFunction; 27 bool Engaged = true; // False once moved-from or release()d. 28 29public: 30 template <typename Fp> 31 explicit scope_exit(Fp &&F) : ExitFunction(std::forward<Fp>(F)) {} 32 33 scope_exit(scope_exit &&Rhs) 34 : ExitFunction(std::move(Rhs.ExitFunction)), Engaged(Rhs.Engaged) { 35 Rhs.release(); 36 } 37 scope_exit(const scope_exit &) = delete; 38 scope_exit &operator=(scope_exit &&) = delete; 39 scope_exit &operator=(const scope_exit &) = delete; 40 41 void release() { Engaged = false; } 42 43 ~scope_exit() { 44 if (Engaged) 45 ExitFunction(); 46 } 47}; 48 49} // end namespace detail 50 51// Keeps the callable object that is passed in, and execute it at the 52// destruction of the returned object (usually at the scope exit where the 53// returned object is kept). 54// 55// Interface is specified by p0052r2. 56template <typename Callable> 57LLVM_NODISCARD detail::scope_exit<typename std::decay<Callable>::type> 58make_scope_exit(Callable &&F) { 59 return detail::scope_exit<typename std::decay<Callable>::type>( 60 std::forward<Callable>(F)); 61} 62 63} // end namespace llvm 64 65#endif 66