ad2fbea797
This has the benefit of consistent placement for these macros (outside the namespace, not inside it). This, in turn, makes it more obvious that the condition applies to the entire namespace scope. Compile times are also reduced a bit, since the compiler doesn't have to open a namespace just to close it again. This is enforced with a clang-tidy check. As a drive-by this also fixes a few macro comments.
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 <__fwd/memory.h>
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#include <__memory/addressof.h>
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#include <__memory/pointer_traits.h>
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#include <__type_traits/is_pointer.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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#if _LIBCPP_STD_VER >= 23
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Smart, class _Pointer, class... _Args>
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class 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 _SmartPtr = __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<_SmartPtr>(__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<_SmartPtr>(__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, _SmartPtr, _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<_SmartPtr>(__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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[[nodiscard]] _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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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER >= 23
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___INOUT_PTR_H
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