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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___INOUT_PTR_H |
| 11 | +#define _LIBCPP___INOUT_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_same.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 | + |
| 36 | +template <class _Smart, class _Pointer, class... _Args> |
| 37 | +class _LIBCPP_TEMPLATE_VIS inout_ptr_t { |
| 38 | + static_assert(!__is_specialization_v<_Smart, shared_ptr>, "std::shared_ptr<> is not supported with std::inout_ptr."); |
| 39 | + |
| 40 | +public: |
| 41 | + _LIBCPP_HIDE_FROM_ABI explicit inout_ptr_t(_Smart& __smart, _Args... __args) |
| 42 | + : __s_(__smart), __a_(std::forward<_Args>(__args)...), __p_([&__smart] { |
| 43 | + if constexpr (is_pointer_v<_Smart>) { |
| 44 | + return __smart; |
| 45 | + } else { |
| 46 | + return __smart.get(); |
| 47 | + } |
| 48 | + }()) { |
| 49 | + if constexpr (requires { __s_.release(); }) { |
| 50 | + __s_.release(); |
| 51 | + } else { |
| 52 | + __s_ = _Smart(); |
| 53 | + } |
| 54 | + } |
| 55 | + |
| 56 | + _LIBCPP_HIDE_FROM_ABI inout_ptr_t(const inout_ptr_t&) = delete; |
| 57 | + |
| 58 | + _LIBCPP_HIDE_FROM_ABI ~inout_ptr_t() { |
| 59 | + // LWG-3897 inout_ptr will not update raw pointer to null |
| 60 | + if constexpr (!is_pointer_v<_Smart>) { |
| 61 | + if (!__p_) { |
| 62 | + return; |
| 63 | + } |
| 64 | + } |
| 65 | + |
| 66 | + using _SP = __pointer_of_or_t<_Smart, _Pointer>; |
| 67 | + if constexpr (is_pointer_v<_Smart>) { |
| 68 | + std::apply([&](auto&&... __args) { __s_ = _Smart(static_cast<_SP>(__p_), std::forward<_Args>(__args)...); }, |
| 69 | + std::move(__a_)); |
| 70 | + } else if constexpr (__resettable_smart_pointer_with_args<_Smart, _Pointer, _Args...>) { |
| 71 | + std::apply([&](auto&&... __args) { __s_.reset(static_cast<_SP>(__p_), std::forward<_Args>(__args)...); }, |
| 72 | + std::move(__a_)); |
| 73 | + } else { |
| 74 | + static_assert(is_constructible_v<_Smart, _SP, _Args...>, |
| 75 | + "The smart pointer must be constructible from arguments of types _Smart, _Pointer, _Args..."); |
| 76 | + std::apply([&](auto&&... __args) { __s_ = _Smart(static_cast<_SP>(__p_), std::forward<_Args>(__args)...); }, |
| 77 | + std::move(__a_)); |
| 78 | + } |
| 79 | + } |
| 80 | + |
| 81 | + _LIBCPP_HIDE_FROM_ABI operator _Pointer*() const noexcept { return std::addressof(const_cast<_Pointer&>(__p_)); } |
| 82 | + |
| 83 | + _LIBCPP_HIDE_FROM_ABI operator void**() const noexcept |
| 84 | + requires(!is_same_v<_Pointer, void*>) |
| 85 | + { |
| 86 | + static_assert(is_pointer_v<_Pointer>, "The conversion to void** requires _Pointer to be a raw pointer."); |
| 87 | + |
| 88 | + return reinterpret_cast<void**>(static_cast<_Pointer*>(*this)); |
| 89 | + } |
| 90 | + |
| 91 | +private: |
| 92 | + _Smart& __s_; |
| 93 | + tuple<_Args...> __a_; |
| 94 | + _Pointer __p_; |
| 95 | +}; |
| 96 | + |
| 97 | +template <class _Pointer = void, class _Smart, class... _Args> |
| 98 | +_LIBCPP_HIDE_FROM_ABI auto inout_ptr(_Smart& __s, _Args&&... __args) { |
| 99 | + using _Ptr = conditional_t<is_void_v<_Pointer>, __pointer_of_t<_Smart>, _Pointer>; |
| 100 | + return std::inout_ptr_t<_Smart, _Ptr, _Args&&...>(__s, std::forward<_Args>(__args)...); |
| 101 | +} |
| 102 | + |
| 103 | +#endif // _LIBCPP_STD_VER >= 23 |
| 104 | + |
| 105 | +_LIBCPP_END_NAMESPACE_STD |
| 106 | + |
| 107 | +_LIBCPP_POP_MACROS |
| 108 | + |
| 109 | +#endif // _LIBCPP___INOUT_PTR_H |
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