mirror of
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109 lines
3.6 KiB
C++
109 lines
3.6 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___INOUT_PTR_H
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#define _LIBCPP___INOUT_PTR_H
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#include <__config>
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#include <__memory/addressof.h>
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#include <__memory/pointer_traits.h>
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#include <__memory/shared_ptr.h>
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#include <__memory/unique_ptr.h>
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#include <__type_traits/is_same.h>
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#include <__type_traits/is_specialization.h>
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#include <__type_traits/is_void.h>
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#include <__utility/forward.h>
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#include <__utility/move.h>
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#include <tuple>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER >= 23
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template <class _Smart, class _Pointer, class... _Args>
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class _LIBCPP_TEMPLATE_VIS inout_ptr_t {
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static_assert(!__is_specialization_v<_Smart, shared_ptr>, "std::shared_ptr<> is not supported with std::inout_ptr.");
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public:
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_LIBCPP_HIDE_FROM_ABI explicit inout_ptr_t(_Smart& __smart, _Args... __args)
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: __s_(__smart), __a_(std::forward<_Args>(__args)...), __p_([&__smart] {
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if constexpr (is_pointer_v<_Smart>) {
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return __smart;
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} else {
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return __smart.get();
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}
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}()) {
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if constexpr (requires { __s_.release(); }) {
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__s_.release();
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} else {
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__s_ = _Smart();
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}
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}
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_LIBCPP_HIDE_FROM_ABI inout_ptr_t(const inout_ptr_t&) = delete;
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_LIBCPP_HIDE_FROM_ABI ~inout_ptr_t() {
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// LWG-3897 inout_ptr will not update raw pointer to null
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if constexpr (!is_pointer_v<_Smart>) {
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if (!__p_) {
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return;
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}
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}
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using _SP = __pointer_of_or_t<_Smart, _Pointer>;
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if constexpr (is_pointer_v<_Smart>) {
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std::apply([&](auto&&... __args) { __s_ = _Smart(static_cast<_SP>(__p_), std::forward<_Args>(__args)...); },
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std::move(__a_));
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} else if constexpr (__resettable_smart_pointer_with_args<_Smart, _Pointer, _Args...>) {
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std::apply([&](auto&&... __args) { __s_.reset(static_cast<_SP>(__p_), std::forward<_Args>(__args)...); },
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std::move(__a_));
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} else {
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static_assert(is_constructible_v<_Smart, _SP, _Args...>,
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"The smart pointer must be constructible from arguments of types _Smart, _Pointer, _Args...");
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std::apply([&](auto&&... __args) { __s_ = _Smart(static_cast<_SP>(__p_), std::forward<_Args>(__args)...); },
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std::move(__a_));
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}
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}
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_LIBCPP_HIDE_FROM_ABI operator _Pointer*() const noexcept { return std::addressof(const_cast<_Pointer&>(__p_)); }
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_LIBCPP_HIDE_FROM_ABI operator void**() const noexcept
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requires(!is_same_v<_Pointer, void*>)
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{
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static_assert(is_pointer_v<_Pointer>, "The conversion to void** requires _Pointer to be a raw pointer.");
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return reinterpret_cast<void**>(static_cast<_Pointer*>(*this));
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}
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private:
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_Smart& __s_;
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tuple<_Args...> __a_;
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_Pointer __p_;
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};
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template <class _Pointer = void, class _Smart, class... _Args>
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_LIBCPP_HIDE_FROM_ABI auto inout_ptr(_Smart& __s, _Args&&... __args) {
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using _Ptr = conditional_t<is_void_v<_Pointer>, __pointer_of_t<_Smart>, _Pointer>;
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return std::inout_ptr_t<_Smart, _Ptr, _Args&&...>(__s, std::forward<_Args>(__args)...);
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}
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#endif // _LIBCPP_STD_VER >= 23
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___INOUT_PTR_H
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