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 36 template <class _Smart, class _Pointer, class... _Args> 37 class _LIBCPP_TEMPLATE_VIS 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 41 public: 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 84 private: 85 _Smart& __s_; 86 tuple<_Args...> __a_; 87 _Pointer __p_ = _Pointer(); 88 }; 89 90 template <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 103