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_EXPERIMENTAL___MEMORY
11#define _LIBCPP_EXPERIMENTAL___MEMORY
12
13#include <__memory/allocator_arg_t.h>
14#include <__memory/uses_allocator.h>
15#include <experimental/__config>
16#include <experimental/utility> // for erased_type
17#include <type_traits>
18
19#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20#  pragma GCC system_header
21#endif
22
23_LIBCPP_BEGIN_NAMESPACE_LFTS
24
25template <
26    class _Tp, class _Alloc
27  , bool = uses_allocator<_Tp, _Alloc>::value
28  , bool = __has_allocator_type<_Tp>::value
29  >
30struct __lfts_uses_allocator : public false_type {};
31
32template <class _Tp, class _Alloc>
33struct __lfts_uses_allocator<_Tp, _Alloc, false, false> : public false_type {};
34
35template <class _Tp, class _Alloc, bool HasAlloc>
36struct __lfts_uses_allocator<_Tp, _Alloc, true, HasAlloc> : public true_type {};
37
38template <class _Tp, class _Alloc>
39struct __lfts_uses_allocator<_Tp, _Alloc, false, true>
40  : public integral_constant<bool
41    , is_convertible<_Alloc, typename _Tp::allocator_type>::value
42      || is_same<erased_type, typename _Tp::allocator_type>::value
43    >
44{};
45
46template <bool _UsesAlloc, class _Tp, class _Alloc, class ..._Args>
47struct __lfts_uses_alloc_ctor_imp
48{
49    static const int value = 0;
50};
51
52template <class _Tp, class _Alloc, class ..._Args>
53struct __lfts_uses_alloc_ctor_imp<true, _Tp, _Alloc, _Args...>
54{
55    static const bool __ic_first
56        = is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
57
58    static const bool __ic_second =
59        __conditional_t<
60            __ic_first,
61            false_type,
62            is_constructible<_Tp, _Args..., _Alloc>
63        >::value;
64
65    static_assert(__ic_first || __ic_second,
66                  "Request for uses allocator construction is ill-formed");
67
68    static const int value = __ic_first ? 1 : 2;
69};
70
71template <class _Tp, class _Alloc, class ..._Args>
72struct __lfts_uses_alloc_ctor
73  : integral_constant<int,
74        __lfts_uses_alloc_ctor_imp<
75            __lfts_uses_allocator<_Tp, _Alloc>::value
76          , _Tp, _Alloc, _Args...
77        >::value
78    >
79{};
80
81template <class _Tp, class _Allocator, class... _Args>
82inline _LIBCPP_INLINE_VISIBILITY
83void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args )
84{
85    new (__storage) _Tp (_VSTD::forward<_Args>(__args)...);
86}
87
88// FIXME: This should have a version which takes a non-const alloc.
89template <class _Tp, class _Allocator, class... _Args>
90inline _LIBCPP_INLINE_VISIBILITY
91void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
92{
93    new (__storage) _Tp (allocator_arg, __a, _VSTD::forward<_Args>(__args)...);
94}
95
96// FIXME: This should have a version which takes a non-const alloc.
97template <class _Tp, class _Allocator, class... _Args>
98inline _LIBCPP_INLINE_VISIBILITY
99void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
100{
101    new (__storage) _Tp (_VSTD::forward<_Args>(__args)..., __a);
102}
103
104template <class _Tp, class _Alloc, class ..._Args>
105inline _LIBCPP_INLINE_VISIBILITY
106void __lfts_user_alloc_construct(
107    _Tp * __store, const _Alloc & __a, _Args &&... __args)
108{
109    ::std::experimental::fundamentals_v1::__user_alloc_construct_impl(
110        typename __lfts_uses_alloc_ctor<_Tp, _Alloc, _Args...>::type()
111       , __store, __a, _VSTD::forward<_Args>(__args)...
112       );
113}
114
115_LIBCPP_END_NAMESPACE_LFTS
116
117#endif /* _LIBCPP_EXPERIMENTAL___MEMORY */
118