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_SCOPEEXIT_H
15#define LLVM_ADT_SCOPEEXIT_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