xref: /freebsd/contrib/llvm-project/libcxx/include/__utility/scope_guard.h (revision 700637cbb5e582861067a11aaca4d053546871d2)
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 <__config>
14 #include <__utility/move.h>
15 
16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17 #  pragma GCC system_header
18 #endif
19 
20 _LIBCPP_PUSH_MACROS
21 #include <__undef_macros>
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 template <class _Func>
26 class __scope_guard {
27   _Func __func_;
28 
29 public:
__scope_guard(_Func __func)30   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __scope_guard(_Func __func) : __func_(std::move(__func)) {}
~__scope_guard()31   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__scope_guard() { __func_(); }
32 
33   __scope_guard(const __scope_guard&)            = delete;
34   __scope_guard& operator=(const __scope_guard&) = delete;
35   __scope_guard& operator=(__scope_guard&&)      = delete;
36 
37 // C++14 doesn't have mandatory RVO, so we have to provide a declaration even though no compiler will ever generate
38 // a call to the move constructor.
39 #if _LIBCPP_STD_VER <= 14
40   __scope_guard(__scope_guard&&);
41 #else
42   __scope_guard(__scope_guard&&) = delete;
43 #endif
44 };
45 
46 template <class _Func>
__make_scope_guard(_Func __func)47 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __scope_guard<_Func> __make_scope_guard(_Func __func) {
48   return __scope_guard<_Func>(std::move(__func));
49 }
50 
51 _LIBCPP_END_NAMESPACE_STD
52 
53 _LIBCPP_POP_MACROS
54 
55 #endif // _LIBCPP___UTILITY_SCOPE_GUARD_H
56