experimental/bits/shared_ptr.h
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// Experimental shared_ptr with array support -*- C++ -*-
// Copyright (C) 2015-2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file experimental/bits/shared_ptr.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{experimental/memory}
*/
#ifndef _GLIBCXX_EXPERIMENTAL_SHARED_PTR_H
#define _GLIBCXX_EXPERIMENTAL_SHARED_PTR_H 1
#pragma GCC system_header
#if __cplusplus >= 201402L
#include <memory>
#include <experimental/type_traits>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace experimental
{
inline namespace fundamentals_v2
{
// 8.2.1
template<typename _Tp> class shared_ptr;
template<typename _Tp> class weak_ptr;
template<typename _Tp> class enable_shared_from_this;
template<typename _Yp, typename _Tp>
constexpr bool __sp_compatible_v
= std::__sp_compatible_with<_Yp*, _Tp*>::value;
template<typename _Tp, typename _Yp>
constexpr bool __sp_is_constructible_v
= std::__sp_is_constructible<_Tp, _Yp>::value;
template<typename _Tp>
class shared_ptr : public __shared_ptr<_Tp>
{
using _Base_type = __shared_ptr<_Tp>;
public:
using element_type = typename _Base_type::element_type;
private:
// Constraint for construction from a pointer of type _Yp*:
template<typename _Yp>
using _SafeConv = enable_if_t<__sp_is_constructible_v<_Tp, _Yp>>;
template<typename _Tp1, typename _Res = void>
using _Compatible
= enable_if_t<__sp_compatible_v<_Tp1, _Tp>, _Res>;
template<typename _Tp1, typename _Del,
typename _Ptr = typename unique_ptr<_Tp1, _Del>::pointer,
typename _Res = void>
using _UniqCompatible = enable_if_t<
__sp_compatible_v<_Tp1, _Tp>
&& experimental::is_convertible_v<_Ptr, element_type*>,
_Res>;
public:
// 8.2.1.1, shared_ptr constructors
constexpr shared_ptr() noexcept = default;
template<typename _Tp1, typename = _SafeConv<_Tp1>>
explicit
shared_ptr(_Tp1* __p) : _Base_type(__p)
{ _M_enable_shared_from_this_with(__p); }
template<typename _Tp1, typename _Deleter, typename = _SafeConv<_Tp1>>
shared_ptr(_Tp1* __p, _Deleter __d)
: _Base_type(__p, __d)
{ _M_enable_shared_from_this_with(__p); }
template<typename _Tp1, typename _Deleter, typename _Alloc,
typename = _SafeConv<_Tp1>>
shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
: _Base_type(__p, __d, __a)
{ _M_enable_shared_from_this_with(__p); }
template<typename _Deleter>
shared_ptr(nullptr_t __p, _Deleter __d)
: _Base_type(__p, __d) { }
template<typename _Deleter, typename _Alloc>
shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
: _Base_type(__p, __d, __a) { }
template<typename _Tp1>
shared_ptr(const shared_ptr<_Tp1>& __r, element_type* __p) noexcept
: _Base_type(__r, __p) { }
shared_ptr(const shared_ptr& __r) noexcept
: _Base_type(__r) { }
template<typename _Tp1, typename = _Compatible<_Tp1>>
shared_ptr(const shared_ptr<_Tp1>& __r) noexcept
: _Base_type(__r) { }
shared_ptr(shared_ptr&& __r) noexcept
: _Base_type(std::move(__r)) { }
template<typename _Tp1, typename = _Compatible<_Tp1>>
shared_ptr(shared_ptr<_Tp1>&& __r) noexcept
: _Base_type(std::move(__r)) { }
template<typename _Tp1, typename = _Compatible<_Tp1>>
explicit
shared_ptr(const weak_ptr<_Tp1>& __r)
: _Base_type(__r) { }
#if _GLIBCXX_USE_DEPRECATED
template<typename _Tp1, typename = _Compatible<_Tp1>>
shared_ptr(std::auto_ptr<_Tp1>&& __r)
: _Base_type(std::move(__r))
{ _M_enable_shared_from_this_with(static_cast<_Tp1*>(this->get())); }
#endif
template<typename _Tp1, typename _Del,
typename = _UniqCompatible<_Tp1, _Del>>
shared_ptr(unique_ptr<_Tp1, _Del>&& __r)
: _Base_type(std::move(__r))
{
// XXX assume conversion from __r.get() to this->get() to __elem_t*
// is a round trip, which might not be true in all cases.
using __elem_t = typename unique_ptr<_Tp1, _Del>::element_type;
_M_enable_shared_from_this_with(static_cast<__elem_t*>(this->get()));
}
constexpr shared_ptr(nullptr_t __p)
: _Base_type(__p) { }
// C++14 §20.8.2.2
~shared_ptr() = default;
// C++14 §20.8.2.3
shared_ptr& operator=(const shared_ptr&) noexcept = default;
template <typename _Tp1>
_Compatible<_Tp1, shared_ptr&>
operator=(const shared_ptr<_Tp1>& __r) noexcept
{
_Base_type::operator=(__r);
return *this;
}
shared_ptr&
operator=(shared_ptr&& __r) noexcept
{
_Base_type::operator=(std::move(__r));
return *this;
}
template <typename _Tp1>
_Compatible<_Tp1, shared_ptr&>
operator=(shared_ptr<_Tp1>&& __r) noexcept
{
_Base_type::operator=(std::move(__r));
return *this;
}
#if _GLIBCXX_USE_DEPRECATED
template<typename _Tp1>
_Compatible<_Tp1, shared_ptr&>
operator=(std::auto_ptr<_Tp1>&& __r)
{
__shared_ptr<_Tp>::operator=(std::move(__r));
return *this;
}
#endif
template <typename _Tp1, typename _Del>
_UniqCompatible<_Tp1, _Del, shared_ptr&>
operator=(unique_ptr<_Tp1, _Del>&& __r)
{
_Base_type::operator=(std::move(__r));
return *this;
}
// C++14 §20.8.2.2.4
// swap & reset
// 8.2.1.2 shared_ptr observers
// in __shared_ptr
private:
template<typename _Alloc, typename... _Args>
shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,
_Args&&... __args)
: _Base_type(__tag, __a, std::forward<_Args>(__args)...)
{ _M_enable_shared_from_this_with(this->get()); }
template<typename _Tp1, typename _Alloc, typename... _Args>
friend shared_ptr<_Tp1>
allocate_shared(const _Alloc& __a, _Args&&... __args);
shared_ptr(const weak_ptr<_Tp>& __r, std::nothrow_t)
: _Base_type(__r, std::nothrow) { }
friend class weak_ptr<_Tp>;
template<typename _Yp>
using __esft_base_t =
decltype(__expt_enable_shared_from_this_base(std::declval<_Yp*>()));
// Detect an accessible and unambiguous enable_shared_from_this base.
template<typename _Yp, typename = void>
struct __has_esft_base
: false_type { };
template<typename _Yp>
struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>>
: __bool_constant<!is_array_v<_Tp>> { }; // ignore base for arrays
template<typename _Yp>
typename enable_if<__has_esft_base<_Yp>::value>::type
_M_enable_shared_from_this_with(const _Yp* __p) noexcept
{
if (auto __base = __expt_enable_shared_from_this_base(__p))
{
__base->_M_weak_this
= shared_ptr<_Yp>(*this, const_cast<_Yp*>(__p));
}
}
template<typename _Yp>
typename enable_if<!__has_esft_base<_Yp>::value>::type
_M_enable_shared_from_this_with(const _Yp*) noexcept
{ }
};
// C++14 §20.8.2.2.7 //DOING
template<typename _Tp1, typename _Tp2>
bool operator==(const shared_ptr<_Tp1>& __a,
const shared_ptr<_Tp2>& __b) noexcept
{ return __a.get() == __b.get(); }
template<typename _Tp>
inline bool
operator==(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
{ return !__a; }
template<typename _Tp>
inline bool
operator==(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
{ return !__a; }
template<typename _Tp1, typename _Tp2>
inline bool
operator!=(const shared_ptr<_Tp1>& __a,
const shared_ptr<_Tp2>& __b) noexcept
{ return __a.get() != __b.get(); }
template<typename _Tp>
inline bool
operator!=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
{ return (bool)__a; }
template<typename _Tp>
inline bool
operator!=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
{ return (bool)__a; }
template<typename _Tp1, typename _Tp2>
inline bool
operator<(const shared_ptr<_Tp1>& __a,
const shared_ptr<_Tp2>& __b) noexcept
{
using __elem_t1 = typename shared_ptr<_Tp1>::element_type;
using __elem_t2 = typename shared_ptr<_Tp2>::element_type;
using _CT = common_type_t<__elem_t1*, __elem_t2*>;
return std::less<_CT>()(__a.get(), __b.get());
}
template<typename _Tp>
inline bool
operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return std::less<__elem_t*>()(__a.get(), nullptr);
}
template<typename _Tp>
inline bool
operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return std::less<__elem_t*>()(nullptr, __a.get());
}
template<typename _Tp1, typename _Tp2>
inline bool
operator<=(const shared_ptr<_Tp1>& __a,
const shared_ptr<_Tp2>& __b) noexcept
{ return !(__b < __a); }
template<typename _Tp>
inline bool
operator<=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
{ return !(nullptr < __a); }
template<typename _Tp>
inline bool
operator<=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
{ return !(__a < nullptr); }
template<typename _Tp1, typename _Tp2>
inline bool
operator>(const shared_ptr<_Tp1>& __a,
const shared_ptr<_Tp2>& __b) noexcept
{ return (__b < __a); }
template<typename _Tp>
inline bool
operator>(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return std::less<__elem_t*>()(nullptr, __a.get());
}
template<typename _Tp>
inline bool
operator>(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return std::less<__elem_t*>()(__a.get(), nullptr);
}
template<typename _Tp1, typename _Tp2>
inline bool
operator>=(const shared_ptr<_Tp1>& __a,
const shared_ptr<_Tp2>& __b) noexcept
{ return !(__a < __b); }
template<typename _Tp>
inline bool
operator>=(const shared_ptr<_Tp>& __a, nullptr_t) noexcept
{ return !(__a < nullptr); }
template<typename _Tp>
inline bool
operator>=(nullptr_t, const shared_ptr<_Tp>& __a) noexcept
{ return !(nullptr < __a); }
// C++14 §20.8.2.2.8
template<typename _Tp>
inline void
swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) noexcept
{ __a.swap(__b); }
// 8.2.1.3, shared_ptr casts
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
static_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return shared_ptr<_Tp>(__r, static_cast<__elem_t*>(__r.get()));
}
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
if (_Tp* __p = dynamic_cast<__elem_t*>(__r.get()))
return shared_ptr<_Tp>(__r, __p);
return shared_ptr<_Tp>();
}
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
const_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return shared_ptr<_Tp>(__r, const_cast<__elem_t*>(__r.get()));
}
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
reinterpret_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept
{
using __elem_t = typename shared_ptr<_Tp>::element_type;
return shared_ptr<_Tp>(__r, reinterpret_cast<__elem_t*>(__r.get()));
}
// C++14 §20.8.2.3
template<typename _Tp>
class weak_ptr : public __weak_ptr<_Tp>
{
template<typename _Tp1, typename _Res = void>
using _Compatible = enable_if_t<__sp_compatible_v<_Tp1, _Tp>, _Res>;
using _Base_type = __weak_ptr<_Tp>;
public:
constexpr weak_ptr() noexcept = default;
template<typename _Tp1, typename = _Compatible<_Tp1>>
weak_ptr(const shared_ptr<_Tp1>& __r) noexcept
: _Base_type(__r) { }
weak_ptr(const weak_ptr&) noexcept = default;
template<typename _Tp1, typename = _Compatible<_Tp1>>
weak_ptr(const weak_ptr<_Tp1>& __r) noexcept
: _Base_type(__r) { }
weak_ptr(weak_ptr&&) noexcept = default;
template<typename _Tp1, typename = _Compatible<_Tp1>>
weak_ptr(weak_ptr<_Tp1>&& __r) noexcept
: _Base_type(std::move(__r)) { }
weak_ptr&
operator=(const weak_ptr& __r) noexcept = default;
template<typename _Tp1>
_Compatible<_Tp1, weak_ptr&>
operator=(const weak_ptr<_Tp1>& __r) noexcept
{
this->_Base_type::operator=(__r);
return *this;
}
template<typename _Tp1>
_Compatible<_Tp1, weak_ptr&>
operator=(const shared_ptr<_Tp1>& __r) noexcept
{
this->_Base_type::operator=(__r);
return *this;
}
weak_ptr&
operator=(weak_ptr&& __r) noexcept = default;
template<typename _Tp1>
_Compatible<_Tp1, weak_ptr&>
operator=(weak_ptr<_Tp1>&& __r) noexcept
{
this->_Base_type::operator=(std::move(__r));
return *this;
}
shared_ptr<_Tp>
lock() const noexcept
{ return shared_ptr<_Tp>(*this, std::nothrow); }
friend class enable_shared_from_this<_Tp>;
};
// C++14 §20.8.2.3.6
template<typename _Tp>
inline void
swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) noexcept
{ __a.swap(__b); }
/// C++14 §20.8.2.2.10
template<typename _Del, typename _Tp>
inline _Del*
get_deleter(const shared_ptr<_Tp>& __p) noexcept
{ return std::get_deleter<_Del>(__p); }
// C++14 §20.8.2.2.11
template<typename _Ch, typename _Tr, typename _Tp>
inline std::basic_ostream<_Ch, _Tr>&
operator<<(std::basic_ostream<_Ch, _Tr>& __os, const shared_ptr<_Tp>& __p)
{
__os << __p.get();
return __os;
}
// C++14 §20.8.2.4
template<typename _Tp = void> class owner_less;
/// Partial specialization of owner_less for shared_ptr.
template<typename _Tp>
struct owner_less<shared_ptr<_Tp>>
: public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
{ };
/// Partial specialization of owner_less for weak_ptr.
template<typename _Tp>
struct owner_less<weak_ptr<_Tp>>
: public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
{ };
template<>
class owner_less<void>
{
template<typename _Tp, typename _Up>
bool
operator()(shared_ptr<_Tp> const& __lhs,
shared_ptr<_Up> const& __rhs) const
{ return __lhs.owner_before(__rhs); }
template<typename _Tp, typename _Up>
bool
operator()(shared_ptr<_Tp> const& __lhs,
weak_ptr<_Up> const& __rhs) const
{ return __lhs.owner_before(__rhs); }
template<typename _Tp, typename _Up>
bool
operator()(weak_ptr<_Tp> const& __lhs,
shared_ptr<_Up> const& __rhs) const
{ return __lhs.owner_before(__rhs); }
template<typename _Tp, typename _Up>
bool
operator()(weak_ptr<_Tp> const& __lhs,
weak_ptr<_Up> const& __rhs) const
{ return __lhs.owner_before(__rhs); }
typedef void is_transparent;
};
// C++14 §20.8.2.6
template<typename _Tp>
inline bool
atomic_is_lock_free(const shared_ptr<_Tp>* __p)
{ return std::atomic_is_lock_free<_Tp, __default_lock_policy>(__p); }
template<typename _Tp>
shared_ptr<_Tp> atomic_load(const shared_ptr<_Tp>* __p)
{ return std::atomic_load<_Tp>(__p); }
template<typename _Tp>
shared_ptr<_Tp>
atomic_load_explicit(const shared_ptr<_Tp>* __p, memory_order __mo)
{ return std::atomic_load_explicit<_Tp>(__p, __mo); }
template<typename _Tp>
void atomic_store(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r)
{ return std::atomic_store<_Tp>(__p, __r); }
template<typename _Tp>
shared_ptr<_Tp>
atomic_store_explicit(const shared_ptr<_Tp>* __p,
shared_ptr<_Tp> __r,
memory_order __mo)
{ return std::atomic_store_explicit<_Tp>(__p, __r, __mo); }
template<typename _Tp>
void atomic_exchange(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r)
{ return std::atomic_exchange<_Tp>(__p, __r); }
template<typename _Tp>
shared_ptr<_Tp>
atomic_exchange_explicit(const shared_ptr<_Tp>* __p,
shared_ptr<_Tp> __r,
memory_order __mo)
{ return std::atomic_exchange_explicit<_Tp>(__p, __r, __mo); }
template<typename _Tp>
bool atomic_compare_exchange_weak(shared_ptr<_Tp>* __p,
shared_ptr<_Tp>* __v,
shared_ptr<_Tp> __w)
{ return std::atomic_compare_exchange_weak<_Tp>(__p, __v, __w); }
template<typename _Tp>
bool atomic_compare_exchange_strong(shared_ptr<_Tp>* __p,
shared_ptr<_Tp>* __v,
shared_ptr<_Tp> __w)
{ return std::atomic_compare_exchange_strong<_Tp>(__p, __v, __w); }
template<typename _Tp>
bool atomic_compare_exchange_weak_explicit(shared_ptr<_Tp>* __p,
shared_ptr<_Tp>* __v,
shared_ptr<_Tp> __w,
memory_order __success,
memory_order __failure)
{ return std::atomic_compare_exchange_weak_explicit<_Tp>(__p, __v, __w,
__success,
__failure); }
template<typename _Tp>
bool atomic_compare_exchange_strong_explicit(shared_ptr<_Tp>* __p,
shared_ptr<_Tp>* __v,
shared_ptr<_Tp> __w,
memory_order __success,
memory_order __failure)
{ return std::atomic_compare_exchange_strong_explicit<_Tp>(__p, __v, __w,
__success,
__failure); }
//enable_shared_from_this
template<typename _Tp>
class enable_shared_from_this
{
protected:
constexpr enable_shared_from_this() noexcept { }
enable_shared_from_this(const enable_shared_from_this&) noexcept { }
enable_shared_from_this&
operator=(const enable_shared_from_this&) noexcept
{ return *this; }
~enable_shared_from_this() { }
public:
shared_ptr<_Tp>
shared_from_this()
{ return shared_ptr<_Tp>(this->_M_weak_this); }
shared_ptr<const _Tp>
shared_from_this() const
{ return shared_ptr<const _Tp>(this->_M_weak_this); }
weak_ptr<_Tp>
weak_from_this() noexcept
{ return _M_weak_this; }
weak_ptr<const _Tp>
weak_from_this() const noexcept
{ return _M_weak_this; }
private:
template<typename _Tp1>
void
_M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const noexcept
{ _M_weak_this._M_assign(__p, __n); }
// Found by ADL when this is an associated class.
friend const enable_shared_from_this*
__expt_enable_shared_from_this_base(const enable_shared_from_this* __p)
{ return __p; }
template<typename>
friend class shared_ptr;
mutable weak_ptr<_Tp> _M_weak_this;
};
} // namespace fundamentals_v2
} // namespace experimental
/// std::hash specialization for shared_ptr.
template<typename _Tp>
struct hash<experimental::shared_ptr<_Tp>>
: public __hash_base<size_t, experimental::shared_ptr<_Tp>>
{
size_t
operator()(const experimental::shared_ptr<_Tp>& __s) const noexcept
{ return std::hash<_Tp*>()(__s.get()); }
};
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __cplusplus <= 201103L
#endif // _GLIBCXX_EXPERIMENTAL_SHARED_PTR_H
std::weak_ptr
A smart pointer with weak semantics.
Definition: bits/shared_ptr.h:535
std::auto_ptr
A simple smart pointer providing strict ownership semantics.
Definition: auto_ptr.h:89
std::hash< _Tp * >
Partial specializations for pointer types.
Definition: functional_hash.h:106
std::enable_if_t
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition: type_traits:2294
std::memory_order
memory_order
Enumeration for memory_order.
Definition: atomic_base.h:55
std::lock
void lock(_L1 &__l1, _L2 &__l2, _L3 &... __l3)
Generic lock.
Definition: mutex:542
type_traits
std::false_type
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:78
std::owner_less
Primary template owner_less.
Definition: bits/shared_ptr.h:616
std::forward
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:74
std::hash
Primary class template hash.
Definition: system_error:142
std::shared_ptr
A smart pointer with reference-counted copy semantics.
Definition: bits/shared_ptr.h:103
memory
std::basic_ostream
Template class basic_ostream.
Definition: iosfwd:86
std::less
One of the comparison functors.
Definition: stl_function.h:340
std
ISO C++ entities toplevel namespace is std.
std::allocate_shared
shared_ptr< _Tp > allocate_shared(const _Alloc &__a, _Args &&... __args)
Create an object that is owned by a shared_ptr.
Definition: bits/shared_ptr.h:703