xref: /llvm-project/libcxx/include/__utility/scope_guard.h (revision adb80d8a4cdc04936980fd88c6c8dd85ccac3135)
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___UTILITY_SCOPE_GUARD_H
11 #define _LIBCPP___UTILITY_SCOPE_GUARD_H
12 
13 #include <__assert>
14 #include <__config>
15 #include <__utility/move.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_PUSH_MACROS
22 #include <__undef_macros>
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 template <class _Func>
27 class __scope_guard {
28   _Func __func_;
29 
30 public:
31   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __scope_guard(_Func __func) : __func_(std::move(__func)) {}
32   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__scope_guard() { __func_(); }
33 
34   __scope_guard(const __scope_guard&)            = delete;
35   __scope_guard& operator=(const __scope_guard&) = delete;
36   __scope_guard& operator=(__scope_guard&&)      = delete;
37 
38 // C++14 doesn't have mandatory RVO, so we have to provide a declaration even though no compiler will ever generate
39 // a call to the move constructor.
40 #if _LIBCPP_STD_VER <= 14
41   __scope_guard(__scope_guard&&);
42 #else
43   __scope_guard(__scope_guard&&) = delete;
44 #endif
45 };
46 
47 template <class _Func>
48 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __scope_guard<_Func> __make_scope_guard(_Func __func) {
49   return __scope_guard<_Func>(std::move(__func));
50 }
51 
52 _LIBCPP_END_NAMESPACE_STD
53 
54 _LIBCPP_POP_MACROS
55 
56 #endif // _LIBCPP___UTILITY_SCOPE_GUARD_H
57