// shared_ptr and weak_ptr implementation -*- C++ -*- // Copyright (C) 2007-2013 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/>. // GCC Note: Based on files from version 1.32.0 of the Boost library. // shared_count.hpp // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. // shared_ptr.hpp // Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes. // Copyright (C) 2001, 2002, 2003 Peter Dimov // weak_ptr.hpp // Copyright (C) 2001, 2002, 2003 Peter Dimov // enable_shared_from_this.hpp // Copyright (C) 2002 Peter Dimov // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) /** @file bits/shared_ptr.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{memory} */ #ifndef _SHARED_PTR_H #define _SHARED_PTR_H 1 #include <bits/shared_ptr_base.h> namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @addtogroup pointer_abstractions * @{ */ /// 2.2.3.7 shared_ptr I/O template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp> inline std::basic_ostream<_Ch, _Tr>& operator<<(std::basic_ostream<_Ch, _Tr>& __os, const __shared_ptr<_Tp, _Lp>& __p) { __os << __p.get(); return __os; } /// 2.2.3.10 shared_ptr get_deleter (experimental) template<typename _Del, typename _Tp, _Lock_policy _Lp> inline _Del* get_deleter(const __shared_ptr<_Tp, _Lp>& __p) noexcept { #ifdef __GXX_RTTI return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); #else return 0; #endif } /** * @brief A smart pointer with reference-counted copy semantics. * * The object pointed to is deleted when the last shared_ptr pointing to * it is destroyed or reset. */ template<typename _Tp> class shared_ptr : public __shared_ptr<_Tp> { public: /** * @brief Construct an empty %shared_ptr. * @post use_count()==0 && get()==0 */ constexpr shared_ptr() noexcept : __shared_ptr<_Tp>() { } shared_ptr(const shared_ptr&) noexcept = default; /** * @brief Construct a %shared_ptr that owns the pointer @a __p. * @param __p A pointer that is convertible to element_type*. * @post use_count() == 1 && get() == __p * @throw std::bad_alloc, in which case @c delete @a __p is called. */ template<typename _Tp1> explicit shared_ptr(_Tp1* __p) : __shared_ptr<_Tp>(__p) { } /** * @brief Construct a %shared_ptr that owns the pointer @a __p * and the deleter @a __d. * @param __p A pointer. * @param __d A deleter. * @post use_count() == 1 && get() == __p * @throw std::bad_alloc, in which case @a __d(__p) is called. * * Requirements: _Deleter's copy constructor and destructor must * not throw * * __shared_ptr will release __p by calling __d(__p) */ template<typename _Tp1, typename _Deleter> shared_ptr(_Tp1* __p, _Deleter __d) : __shared_ptr<_Tp>(__p, __d) { } /** * @brief Construct a %shared_ptr that owns a null pointer * and the deleter @a __d. * @param __p A null pointer constant. * @param __d A deleter. * @post use_count() == 1 && get() == __p * @throw std::bad_alloc, in which case @a __d(__p) is called. * * Requirements: _Deleter's copy constructor and destructor must * not throw * * The last owner will call __d(__p) */ template<typename _Deleter> shared_ptr(nullptr_t __p, _Deleter __d) : __shared_ptr<_Tp>(__p, __d) { } /** * @brief Construct a %shared_ptr that owns the pointer @a __p * and the deleter @a __d. * @param __p A pointer. * @param __d A deleter. * @param __a An allocator. * @post use_count() == 1 && get() == __p * @throw std::bad_alloc, in which case @a __d(__p) is called. * * Requirements: _Deleter's copy constructor and destructor must * not throw _Alloc's copy constructor and destructor must not * throw. * * __shared_ptr will release __p by calling __d(__p) */ template<typename _Tp1, typename _Deleter, typename _Alloc> shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a) : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { } /** * @brief Construct a %shared_ptr that owns a null pointer * and the deleter @a __d. * @param __p A null pointer constant. * @param __d A deleter. * @param __a An allocator. * @post use_count() == 1 && get() == __p * @throw std::bad_alloc, in which case @a __d(__p) is called. * * Requirements: _Deleter's copy constructor and destructor must * not throw _Alloc's copy constructor and destructor must not * throw. * * The last owner will call __d(__p) */ template<typename _Deleter, typename _Alloc> shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a) : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { } // Aliasing constructor /** * @brief Constructs a %shared_ptr instance that stores @a __p * and shares ownership with @a __r. * @param __r A %shared_ptr. * @param __p A pointer that will remain valid while @a *__r is valid. * @post get() == __p && use_count() == __r.use_count() * * This can be used to construct a @c shared_ptr to a sub-object * of an object managed by an existing @c shared_ptr. * * @code * shared_ptr< pair<int,int> > pii(new pair<int,int>()); * shared_ptr<int> pi(pii, &pii->first); * assert(pii.use_count() == 2); * @endcode */ template<typename _Tp1> shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p) noexcept : __shared_ptr<_Tp>(__r, __p) { } /** * @brief If @a __r is empty, constructs an empty %shared_ptr; * otherwise construct a %shared_ptr that shares ownership * with @a __r. * @param __r A %shared_ptr. * @post get() == __r.get() && use_count() == __r.use_count() */ template<typename _Tp1, typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> shared_ptr(const shared_ptr<_Tp1>& __r) noexcept : __shared_ptr<_Tp>(__r) { } /** * @brief Move-constructs a %shared_ptr instance from @a __r. * @param __r A %shared_ptr rvalue. * @post *this contains the old value of @a __r, @a __r is empty. */ shared_ptr(shared_ptr&& __r) noexcept : __shared_ptr<_Tp>(std::move(__r)) { } /** * @brief Move-constructs a %shared_ptr instance from @a __r. * @param __r A %shared_ptr rvalue. * @post *this contains the old value of @a __r, @a __r is empty. */ template<typename _Tp1, typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> shared_ptr(shared_ptr<_Tp1>&& __r) noexcept : __shared_ptr<_Tp>(std::move(__r)) { } /** * @brief Constructs a %shared_ptr that shares ownership with @a __r * and stores a copy of the pointer stored in @a __r. * @param __r A weak_ptr. * @post use_count() == __r.use_count() * @throw bad_weak_ptr when __r.expired(), * in which case the constructor has no effect. */ template<typename _Tp1> explicit shared_ptr(const weak_ptr<_Tp1>& __r) : __shared_ptr<_Tp>(__r) { } #if _GLIBCXX_USE_DEPRECATED template<typename _Tp1> shared_ptr(std::auto_ptr<_Tp1>&& __r); #endif template<typename _Tp1, typename _Del> shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r) : __shared_ptr<_Tp>(std::move(__r)) { } /** * @brief Construct an empty %shared_ptr. * @param __p A null pointer constant. * @post use_count() == 0 && get() == nullptr */ constexpr shared_ptr(nullptr_t __p) noexcept : __shared_ptr<_Tp>(__p) { } shared_ptr& operator=(const shared_ptr&) noexcept = default; template<typename _Tp1> shared_ptr& operator=(const shared_ptr<_Tp1>& __r) noexcept { this->__shared_ptr<_Tp>::operator=(__r); return *this; } #if _GLIBCXX_USE_DEPRECATED template<typename _Tp1> shared_ptr& operator=(std::auto_ptr<_Tp1>&& __r) { this->__shared_ptr<_Tp>::operator=(std::move(__r)); return *this; } #endif shared_ptr& operator=(shared_ptr&& __r) noexcept { this->__shared_ptr<_Tp>::operator=(std::move(__r)); return *this; } template<class _Tp1> shared_ptr& operator=(shared_ptr<_Tp1>&& __r) noexcept { this->__shared_ptr<_Tp>::operator=(std::move(__r)); return *this; } template<typename _Tp1, typename _Del> shared_ptr& operator=(std::unique_ptr<_Tp1, _Del>&& __r) { this->__shared_ptr<_Tp>::operator=(std::move(__r)); return *this; } private: // This constructor is non-standard, it is used by allocate_shared. template<typename _Alloc, typename... _Args> shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a, _Args&&... __args) : __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...) { } template<typename _Tp1, typename _Alloc, typename... _Args> friend shared_ptr<_Tp1> allocate_shared(const _Alloc& __a, _Args&&... __args); }; // 20.7.2.2.7 shared_ptr comparisons 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 !__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 { typedef typename std::common_type<_Tp1*, _Tp2*>::type _CT; return std::less<_CT>()(__a.get(), __b.get()); } template<typename _Tp> inline bool operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept { return std::less<_Tp*>()(__a.get(), nullptr); } template<typename _Tp> inline bool operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept { return std::less<_Tp*>()(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 { return std::less<_Tp*>()(nullptr, __a.get()); } template<typename _Tp> inline bool operator>(nullptr_t, const shared_ptr<_Tp>& __a) noexcept { return std::less<_Tp*>()(__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); } template<typename _Tp> struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>> { }; // 20.7.2.2.8 shared_ptr specialized algorithms. template<typename _Tp> inline void swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) noexcept { __a.swap(__b); } // 20.7.2.2.9 shared_ptr casts. template<typename _Tp, typename _Tp1> inline shared_ptr<_Tp> static_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept { return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); } template<typename _Tp, typename _Tp1> inline shared_ptr<_Tp> const_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept { return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); } template<typename _Tp, typename _Tp1> inline shared_ptr<_Tp> dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) noexcept { if (_Tp* __p = dynamic_cast<_Tp*>(__r.get())) return shared_ptr<_Tp>(__r, __p); return shared_ptr<_Tp>(); } /** * @brief A smart pointer with weak semantics. * * With forwarding constructors and assignment operators. */ template<typename _Tp> class weak_ptr : public __weak_ptr<_Tp> { public: constexpr weak_ptr() noexcept : __weak_ptr<_Tp>() { } template<typename _Tp1, typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> weak_ptr(const weak_ptr<_Tp1>& __r) noexcept : __weak_ptr<_Tp>(__r) { } template<typename _Tp1, typename = typename std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> weak_ptr(const shared_ptr<_Tp1>& __r) noexcept : __weak_ptr<_Tp>(__r) { } template<typename _Tp1> weak_ptr& operator=(const weak_ptr<_Tp1>& __r) noexcept { this->__weak_ptr<_Tp>::operator=(__r); return *this; } template<typename _Tp1> weak_ptr& operator=(const shared_ptr<_Tp1>& __r) noexcept { this->__weak_ptr<_Tp>::operator=(__r); return *this; } shared_ptr<_Tp> lock() const noexcept { #ifdef __GTHREADS if (this->expired()) return shared_ptr<_Tp>(); __try { return shared_ptr<_Tp>(*this); } __catch(const bad_weak_ptr&) { return shared_ptr<_Tp>(); } #else return this->expired() ? shared_ptr<_Tp>() : shared_ptr<_Tp>(*this); #endif } }; // 20.7.2.3.6 weak_ptr specialized algorithms. template<typename _Tp> inline void swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) noexcept { __a.swap(__b); } /// Primary template owner_less template<typename _Tp> struct 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>> { }; /** * @brief Base class allowing use of member function 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); } private: template<typename _Tp1> void _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const noexcept { _M_weak_this._M_assign(__p, __n); } template<typename _Tp1> friend void __enable_shared_from_this_helper(const __shared_count<>& __pn, const enable_shared_from_this* __pe, const _Tp1* __px) noexcept { if (__pe != 0) __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn); } mutable weak_ptr<_Tp> _M_weak_this; }; /** * @brief Create an object that is owned by a shared_ptr. * @param __a An allocator. * @param __args Arguments for the @a _Tp object's constructor. * @return A shared_ptr that owns the newly created object. * @throw An exception thrown from @a _Alloc::allocate or from the * constructor of @a _Tp. * * A copy of @a __a will be used to allocate memory for the shared_ptr * and the new object. */ template<typename _Tp, typename _Alloc, typename... _Args> inline shared_ptr<_Tp> allocate_shared(const _Alloc& __a, _Args&&... __args) { return shared_ptr<_Tp>(_Sp_make_shared_tag(), __a, std::forward<_Args>(__args)...); } /** * @brief Create an object that is owned by a shared_ptr. * @param __args Arguments for the @a _Tp object's constructor. * @return A shared_ptr that owns the newly created object. * @throw std::bad_alloc, or an exception thrown from the * constructor of @a _Tp. */ template<typename _Tp, typename... _Args> inline shared_ptr<_Tp> make_shared(_Args&&... __args) { typedef typename std::remove_const<_Tp>::type _Tp_nc; return std::allocate_shared<_Tp>(std::allocator<_Tp_nc>(), std::forward<_Args>(__args)...); } /// std::hash specialization for shared_ptr. template<typename _Tp> struct hash<shared_ptr<_Tp>> : public __hash_base<size_t, shared_ptr<_Tp>> { size_t operator()(const shared_ptr<_Tp>& __s) const noexcept { return std::hash<_Tp*>()(__s.get()); } }; // @} group pointer_abstractions _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif // _SHARED_PTR_H