1//===----------------------------------------------------------------------===//
 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#ifndef _LIBCPP___MEMORY_TEMP_VALUE_H
10#define _LIBCPP___MEMORY_TEMP_VALUE_H
11
12#include <__config>
13#include <__memory/addressof.h>
14#include <__memory/allocator_traits.h>
15#include <__type_traits/aligned_storage.h>
16#include <__utility/forward.h>
17
18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19#  pragma GCC system_header
20#endif
21
22_LIBCPP_BEGIN_NAMESPACE_STD
23
24template <class _Tp, class _Alloc>
25struct __temp_value {
26  typedef allocator_traits<_Alloc> _Traits;
27
28#ifdef _LIBCPP_CXX03_LANG
29  typename aligned_storage<sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)>::type __v;
30#else
31  union {
32    _Tp __v;
33  };
34#endif
35  _Alloc& __a;
36
37  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp* __addr() {
38#ifdef _LIBCPP_CXX03_LANG
39    return reinterpret_cast<_Tp*>(std::addressof(__v));
40#else
41    return std::addressof(__v);
42#endif
43  }
44
45  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& get() { return *__addr(); }
46
47  template <class... _Args>
48  _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI _LIBCPP_CONSTEXPR_SINCE_CXX20 __temp_value(_Alloc& __alloc, _Args&&... __args)
49      : __a(__alloc) {
50    _Traits::construct(__a, __addr(), std::forward<_Args>(__args)...);
51  }
52
53  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__temp_value() { _Traits::destroy(__a, __addr()); }
54};
55
56_LIBCPP_END_NAMESPACE_STD
57
58#endif // _LIBCPP___MEMORY_TEMP_VALUE_H