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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___OUT_PTR_H
11#define _LIBCPP___OUT_PTR_H
12
13#include <__config>
14#include <__memory/addressof.h>
15#include <__memory/pointer_traits.h>
16#include <__memory/shared_ptr.h>
17#include <__memory/unique_ptr.h>
18#include <__type_traits/is_pointer.h>
19#include <__type_traits/is_specialization.h>
20#include <__type_traits/is_void.h>
21#include <__utility/forward.h>
22#include <__utility/move.h>
23#include <tuple>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26# pragma GCC system_header
27#endif
28
29_LIBCPP_PUSH_MACROS
30#include <__undef_macros>
31
32_LIBCPP_BEGIN_NAMESPACE_STD
33
34#if _LIBCPP_STD_VER >= 23
35
36template <class _Smart, class _Pointer, class... _Args>
37class out_ptr_t {
38 static_assert(!__is_specialization_v<_Smart, shared_ptr> || sizeof...(_Args) > 0,
39 "Using std::shared_ptr<> without a deleter in std::out_ptr is not supported.");
40
41public:
42 _LIBCPP_HIDE_FROM_ABI explicit out_ptr_t(_Smart& __smart, _Args... __args)
43 : __s_(__smart), __a_(std::forward<_Args>(__args)...), __p_() {
44 using _Ptr = decltype(__smart);
45 if constexpr (__resettable_smart_pointer<_Ptr>) {
46 __s_.reset();
47 } else if constexpr (is_constructible_v<_Smart>) {
48 __s_ = _Smart();
49 } else {
50 static_assert(__resettable_smart_pointer<_Ptr> || is_constructible_v<_Smart>,
51 "The adapted pointer type must have a reset() member function or be default constructible.");
52 }
53 }
54
55 _LIBCPP_HIDE_FROM_ABI out_ptr_t(const out_ptr_t&) = delete;
56
57 _LIBCPP_HIDE_FROM_ABI ~out_ptr_t() {
58 if (!__p_) {
59 return;
60 }
61
62 using _SmartPtr = __pointer_of_or_t<_Smart, _Pointer>;
63 if constexpr (__resettable_smart_pointer_with_args<_Smart, _Pointer, _Args...>) {
64 std::apply([&](auto&&... __args) { __s_.reset(static_cast<_SmartPtr>(__p_), std::forward<_Args>(__args)...); },
65 std::move(__a_));
66 } else {
67 static_assert(is_constructible_v<_Smart, _SmartPtr, _Args...>,
68 "The smart pointer must be constructible from arguments of types _Smart, _Pointer, _Args...");
69 std::apply([&](auto&&... __args) { __s_ = _Smart(static_cast<_SmartPtr>(__p_), std::forward<_Args>(__args)...); },
70 std::move(__a_));
71 }
72 }
73
74 _LIBCPP_HIDE_FROM_ABI operator _Pointer*() const noexcept { return std::addressof(const_cast<_Pointer&>(__p_)); }
75
76 _LIBCPP_HIDE_FROM_ABI operator void**() const noexcept
77 requires(!is_same_v<_Pointer, void*>)
78 {
79 static_assert(is_pointer_v<_Pointer>, "The conversion to void** requires _Pointer to be a raw pointer.");
80
81 return reinterpret_cast<void**>(static_cast<_Pointer*>(*this));
82 }
83
84private:
85 _Smart& __s_;
86 tuple<_Args...> __a_;
87 _Pointer __p_ = _Pointer();
88};
89
90template <class _Pointer = void, class _Smart, class... _Args>
91_LIBCPP_HIDE_FROM_ABI auto out_ptr(_Smart& __s, _Args&&... __args) {
92 using _Ptr = conditional_t<is_void_v<_Pointer>, __pointer_of_t<_Smart>, _Pointer>;
93 return std::out_ptr_t<_Smart, _Ptr, _Args&&...>(__s, std::forward<_Args>(__args)...);
94}
95
96#endif // _LIBCPP_STD_VER >= 23
97
98_LIBCPP_END_NAMESPACE_STD
99
100_LIBCPP_POP_MACROS
101
102#endif // _LIBCPP___OUT_PTR_H