mirror-llvm-project/libcxx/include/experimental/memory
Nikolas Klauser ad2fbea797
[libc++] Consistently use version guards outside namespace macros (#181136)
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.
2026-06-29 14:44:44 +02:00

203 lines
6 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_EXPERIMENTAL_MEMORY
#define _LIBCPP_EXPERIMENTAL_MEMORY
/*
experimental/memory synopsis
namespace std::experimental::inline fundamentals_v2 {
template <class W> class observer_ptr {
public:
using element_type = W;
using pointer = add_pointer_t<W>; // exposition-only
using reference = add_lvalue_reference_t<W>; // exposition-only
// default ctor
constexpr observer_ptr() noexcept;
// pointer-accepting ctors
constexpr observer_ptr(nullptr_t) noexcept;
constexpr explicit observer_ptr(pointer) noexcept;
// copying ctors (in addition to compiler-generated copy ctor)
template <class W2> constexpr observer_ptr(observer_ptr<W2>) noexcept;
// observers
constexpr pointer get() const noexcept;
constexpr reference operator*() const;
constexpr pointer operator->() const noexcept;
constexpr explicit operator bool() const noexcept;
// conversions
constexpr explicit operator pointer() const noexcept;
// modifiers
constexpr pointer release() noexcept;
constexpr void reset(pointer = nullptr) noexcept;
constexpr void swap(observer_ptr&) noexcept;
};
}
*/
#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
# include <__cxx03/__config>
#else
# include <__config>
# include <__cstddef/nullptr_t.h>
# include <__cstddef/size_t.h>
# include <__functional/hash.h>
# include <__functional/operations.h>
# include <__type_traits/add_pointer.h>
# include <__type_traits/add_reference.h>
# include <__type_traits/common_type.h>
# include <__type_traits/enable_if.h>
# include <__type_traits/is_convertible.h>
# include <version>
# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
# endif
# ifdef _LIBCPP_ENABLE_EXPERIMENTAL
# if _LIBCPP_STD_VER >= 17
_LIBCPP_BEGIN_NAMESPACE_LFTS_V2
template <class _Wp>
class observer_ptr {
public:
using element_type = _Wp;
// constructors
_LIBCPP_HIDE_FROM_ABI constexpr observer_ptr() noexcept : __ptr_(nullptr) {}
_LIBCPP_HIDE_FROM_ABI constexpr observer_ptr(nullptr_t) noexcept : __ptr_(nullptr) {}
_LIBCPP_HIDE_FROM_ABI constexpr explicit observer_ptr(element_type* __p) noexcept : __ptr_(__p) {}
template <class _W2, __enable_if_t<is_convertible<_W2*, _Wp*>::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI constexpr observer_ptr(observer_ptr<_W2> __other) noexcept : __ptr_(__other.get()) {}
// observers
_LIBCPP_HIDE_FROM_ABI constexpr element_type* get() const noexcept { return __ptr_; }
_LIBCPP_HIDE_FROM_ABI constexpr add_lvalue_reference_t<_Wp> operator*() const { return *__ptr_; }
_LIBCPP_HIDE_FROM_ABI constexpr element_type* operator->() const noexcept { return __ptr_; }
_LIBCPP_HIDE_FROM_ABI constexpr explicit operator bool() const noexcept { return __ptr_ != nullptr; }
// conversions
_LIBCPP_HIDE_FROM_ABI constexpr explicit operator element_type*() const noexcept { return __ptr_; }
// modifiers
_LIBCPP_HIDE_FROM_ABI constexpr void reset(element_type* __p = nullptr) noexcept { __ptr_ = __p; }
_LIBCPP_HIDE_FROM_ABI constexpr void swap(observer_ptr& __other) noexcept {
observer_ptr __tmp = __other;
__other = *this;
*this = __tmp;
}
_LIBCPP_HIDE_FROM_ABI constexpr element_type* release() noexcept {
observer_ptr __p;
__p.swap(*this);
return __p.get();
}
private:
element_type* __ptr_;
};
// specializations
template <class _Wp>
_LIBCPP_HIDE_FROM_ABI constexpr void swap(observer_ptr<_Wp>& __a, observer_ptr<_Wp>& __b) noexcept {
__a.swap(__b);
}
template <class _Wp>
_LIBCPP_HIDE_FROM_ABI observer_ptr<_Wp> make_observer(_Wp* __ptr) noexcept {
return observer_ptr<_Wp>{__ptr};
}
template <class _W1, class _W2>
_LIBCPP_HIDE_FROM_ABI bool operator==(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {
return __a.get() == __b.get();
}
template <class _W1, class _W2>
_LIBCPP_HIDE_FROM_ABI bool operator!=(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {
return !(__a == __b);
}
template <class _Wp>
_LIBCPP_HIDE_FROM_ABI bool operator==(observer_ptr<_Wp> __p, nullptr_t) {
return !__p;
}
template <class _Wp>
_LIBCPP_HIDE_FROM_ABI bool operator==(nullptr_t, observer_ptr<_Wp> __p) {
return !__p;
}
template <class _Wp>
_LIBCPP_HIDE_FROM_ABI bool operator!=(observer_ptr<_Wp> __p, nullptr_t) {
return (bool)__p;
}
template <class _Wp>
_LIBCPP_HIDE_FROM_ABI bool operator!=(nullptr_t, observer_ptr<_Wp> __p) {
return (bool)__p;
}
template <class _W1, class _W2>
_LIBCPP_HIDE_FROM_ABI bool operator<(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {
return std::less<typename std::common_type<_W1*, _W2*>::type>()(__a.get(), __b.get());
}
template <class _W1, class _W2>
_LIBCPP_HIDE_FROM_ABI bool operator>(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {
return __b < __a;
}
template <class _W1, class _W2>
_LIBCPP_HIDE_FROM_ABI bool operator<=(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {
return !(__a > __b);
}
template <class _W1, class _W2>
_LIBCPP_HIDE_FROM_ABI bool operator>=(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {
return !(__a < __b);
}
_LIBCPP_END_NAMESPACE_LFTS_V2
_LIBCPP_BEGIN_NAMESPACE_STD
// hash
template <class _Tp>
struct hash<experimental::observer_ptr<_Tp>> {
_LIBCPP_HIDE_FROM_ABI size_t operator()(const experimental::observer_ptr<_Tp>& __ptr) const noexcept {
return hash<_Tp*>()(__ptr.get());
}
};
_LIBCPP_END_NAMESPACE_STD
# endif // _LIBCPP_STD_VER >= 17
# endif // _LIBCPP_ENABLE_EXPERIMENTAL
# if defined(_LIBCPP_KEEP_TRANSITIVE_INCLUDES_LLVM23) && _LIBCPP_STD_VER <= 20
# include <cstddef>
# include <limits>
# endif
#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
#endif /* _LIBCPP_EXPERIMENTAL_MEMORY */