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Diffstat (limited to 'libstdc++-v3/include/bits/shared_ptr_base.h')
| -rw-r--r-- | libstdc++-v3/include/bits/shared_ptr_base.h | 1386 |
1 files changed, 1386 insertions, 0 deletions
diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h b/libstdc++-v3/include/bits/shared_ptr_base.h new file mode 100644 index 000000000..bc34aff14 --- /dev/null +++ b/libstdc++-v3/include/bits/shared_ptr_base.h @@ -0,0 +1,1386 @@ +// shared_ptr and weak_ptr implementation details -*- C++ -*- + +// Copyright (C) 2007, 2008, 2009, 2010, 2011 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_base.h + * This is an internal header file, included by other library headers. + * Do not attempt to use it directly. @headername{memory} + */ + +#ifndef _SHARED_PTR_BASE_H +#define _SHARED_PTR_BASE_H 1 + +namespace std _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + + /** + * @brief Exception possibly thrown by @c shared_ptr. + * @ingroup exceptions + */ + class bad_weak_ptr : public std::exception + { + public: + virtual char const* + what() const throw(); + + virtual ~bad_weak_ptr() throw(); + }; + + // Substitute for bad_weak_ptr object in the case of -fno-exceptions. + inline void + __throw_bad_weak_ptr() + { +#if __EXCEPTIONS + throw bad_weak_ptr(); +#else + __builtin_abort(); +#endif + } + + using __gnu_cxx::_Lock_policy; + using __gnu_cxx::__default_lock_policy; + using __gnu_cxx::_S_single; + using __gnu_cxx::_S_mutex; + using __gnu_cxx::_S_atomic; + + // Empty helper class except when the template argument is _S_mutex. + template<_Lock_policy _Lp> + class _Mutex_base + { + protected: + // The atomic policy uses fully-fenced builtins, single doesn't care. + enum { _S_need_barriers = 0 }; + }; + + template<> + class _Mutex_base<_S_mutex> + : public __gnu_cxx::__mutex + { + protected: + // This policy is used when atomic builtins are not available. + // The replacement atomic operations might not have the necessary + // memory barriers. + enum { _S_need_barriers = 1 }; + }; + + template<_Lock_policy _Lp = __default_lock_policy> + class _Sp_counted_base + : public _Mutex_base<_Lp> + { + public: + _Sp_counted_base() + : _M_use_count(1), _M_weak_count(1) { } + + virtual + ~_Sp_counted_base() // nothrow + { } + + // Called when _M_use_count drops to zero, to release the resources + // managed by *this. + virtual void + _M_dispose() = 0; // nothrow + + // Called when _M_weak_count drops to zero. + virtual void + _M_destroy() // nothrow + { delete this; } + + virtual void* + _M_get_deleter(const std::type_info&) = 0; + + void + _M_add_ref_copy() + { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); } + + void + _M_add_ref_lock(); + + void + _M_release() // nothrow + { + // Be race-detector-friendly. For more info see bits/c++config. + _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count); + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1) + { + _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count); + _M_dispose(); + // There must be a memory barrier between dispose() and destroy() + // to ensure that the effects of dispose() are observed in the + // thread that runs destroy(). + // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html + if (_Mutex_base<_Lp>::_S_need_barriers) + { + _GLIBCXX_READ_MEM_BARRIER; + _GLIBCXX_WRITE_MEM_BARRIER; + } + + // Be race-detector-friendly. For more info see bits/c++config. + _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, + -1) == 1) + { + _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); + _M_destroy(); + } + } + } + + void + _M_weak_add_ref() // nothrow + { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); } + + void + _M_weak_release() // nothrow + { + // Be race-detector-friendly. For more info see bits/c++config. + _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1) + { + _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); + if (_Mutex_base<_Lp>::_S_need_barriers) + { + // See _M_release(), + // destroy() must observe results of dispose() + _GLIBCXX_READ_MEM_BARRIER; + _GLIBCXX_WRITE_MEM_BARRIER; + } + _M_destroy(); + } + } + + long + _M_get_use_count() const // nothrow + { + // No memory barrier is used here so there is no synchronization + // with other threads. + return const_cast<const volatile _Atomic_word&>(_M_use_count); + } + + private: + _Sp_counted_base(_Sp_counted_base const&); + _Sp_counted_base& operator=(_Sp_counted_base const&); + + _Atomic_word _M_use_count; // #shared + _Atomic_word _M_weak_count; // #weak + (#shared != 0) + }; + + template<> + inline void + _Sp_counted_base<_S_single>:: + _M_add_ref_lock() + { + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0) + { + _M_use_count = 0; + __throw_bad_weak_ptr(); + } + } + + template<> + inline void + _Sp_counted_base<_S_mutex>:: + _M_add_ref_lock() + { + __gnu_cxx::__scoped_lock sentry(*this); + if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0) + { + _M_use_count = 0; + __throw_bad_weak_ptr(); + } + } + + template<> + inline void + _Sp_counted_base<_S_atomic>:: + _M_add_ref_lock() + { + // Perform lock-free add-if-not-zero operation. + _Atomic_word __count; + do + { + __count = _M_use_count; + if (__count == 0) + __throw_bad_weak_ptr(); + + // Replace the current counter value with the old value + 1, as + // long as it's not changed meanwhile. + } + while (!__sync_bool_compare_and_swap(&_M_use_count, __count, + __count + 1)); + } + + + // Forward declarations. + template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> + class __shared_ptr; + + template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> + class __weak_ptr; + + template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> + class __enable_shared_from_this; + + template<typename _Tp> + class shared_ptr; + + template<typename _Tp> + class weak_ptr; + + template<typename _Tp> + struct owner_less; + + template<typename _Tp> + class enable_shared_from_this; + + template<_Lock_policy _Lp = __default_lock_policy> + class __weak_count; + + template<_Lock_policy _Lp = __default_lock_policy> + class __shared_count; + + + // Counted ptr with no deleter or allocator support + template<typename _Ptr, _Lock_policy _Lp> + class _Sp_counted_ptr : public _Sp_counted_base<_Lp> + { + public: + explicit + _Sp_counted_ptr(_Ptr __p) + : _M_ptr(__p) { } + + virtual void + _M_dispose() // nothrow + { delete _M_ptr; } + + virtual void + _M_destroy() // nothrow + { delete this; } + + virtual void* + _M_get_deleter(const std::type_info&) + { return 0; } + + _Sp_counted_ptr(const _Sp_counted_ptr&) = delete; + _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete; + + protected: + _Ptr _M_ptr; // copy constructor must not throw + }; + + template<> + inline void + _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() { } + + template<> + inline void + _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() { } + + template<> + inline void + _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() { } + + // Support for custom deleter and/or allocator + template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp> + class _Sp_counted_deleter : public _Sp_counted_base<_Lp> + { + typedef typename _Alloc::template + rebind<_Sp_counted_deleter>::other _My_alloc_type; + + // Helper class that stores the Deleter and also acts as an allocator. + // Used to dispose of the owned pointer and the internal refcount + // Requires that copies of _Alloc can free each other's memory. + struct _My_Deleter + : public _My_alloc_type // copy constructor must not throw + { + _Deleter _M_del; // copy constructor must not throw + _My_Deleter(_Deleter __d, const _Alloc& __a) + : _My_alloc_type(__a), _M_del(__d) { } + }; + + public: + // __d(__p) must not throw. + _Sp_counted_deleter(_Ptr __p, _Deleter __d) + : _M_ptr(__p), _M_del(__d, _Alloc()) { } + + // __d(__p) must not throw. + _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) + : _M_ptr(__p), _M_del(__d, __a) { } + + virtual void + _M_dispose() // nothrow + { _M_del._M_del(_M_ptr); } + + virtual void + _M_destroy() // nothrow + { + _My_alloc_type __a(_M_del); + this->~_Sp_counted_deleter(); + __a.deallocate(this, 1); + } + + virtual void* + _M_get_deleter(const std::type_info& __ti) + { +#ifdef __GXX_RTTI + return __ti == typeid(_Deleter) ? &_M_del._M_del : 0; +#else + return 0; +#endif + } + + protected: + _Ptr _M_ptr; // copy constructor must not throw + _My_Deleter _M_del; // copy constructor must not throw + }; + + // helpers for make_shared / allocate_shared + + template<typename _Tp> + struct _Sp_destroy_inplace + { + void operator()(_Tp* __p) const { if (__p) __p->~_Tp(); } + }; + + struct _Sp_make_shared_tag { }; + + template<typename _Tp, typename _Alloc, _Lock_policy _Lp> + class _Sp_counted_ptr_inplace + : public _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp> + { + typedef _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp> + _Base_type; + + public: + explicit + _Sp_counted_ptr_inplace(_Alloc __a) + : _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a) + , _M_storage() + { + void* __p = &_M_storage; + ::new (__p) _Tp(); // might throw + _Base_type::_M_ptr = static_cast<_Tp*>(__p); + } + + template<typename... _Args> + _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args) + : _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a) + , _M_storage() + { + void* __p = &_M_storage; + ::new (__p) _Tp(std::forward<_Args>(__args)...); // might throw + _Base_type::_M_ptr = static_cast<_Tp*>(__p); + } + + // Override because the allocator needs to know the dynamic type + virtual void + _M_destroy() // nothrow + { + typedef typename _Alloc::template + rebind<_Sp_counted_ptr_inplace>::other _My_alloc_type; + _My_alloc_type __a(_Base_type::_M_del); + this->~_Sp_counted_ptr_inplace(); + __a.deallocate(this, 1); + } + + // Sneaky trick so __shared_ptr can get the managed pointer + virtual void* + _M_get_deleter(const std::type_info& __ti) + { +#ifdef __GXX_RTTI + return __ti == typeid(_Sp_make_shared_tag) + ? static_cast<void*>(&_M_storage) + : _Base_type::_M_get_deleter(__ti); +#else + return 0; +#endif + } + + private: + typename aligned_storage<sizeof(_Tp), alignment_of<_Tp>::value>::type + _M_storage; + }; + + template<_Lock_policy _Lp> + class __shared_count + { + public: + constexpr __shared_count() : _M_pi(0) // nothrow + { } + + template<typename _Ptr> + explicit + __shared_count(_Ptr __p) : _M_pi(0) + { + __try + { + _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p); + } + __catch(...) + { + delete __p; + __throw_exception_again; + } + } + + template<typename _Ptr, typename _Deleter> + __shared_count(_Ptr __p, _Deleter __d) : _M_pi(0) + { + // The allocator's value_type doesn't matter, will rebind it anyway. + typedef std::allocator<int> _Alloc; + typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type; + typedef std::allocator<_Sp_cd_type> _Alloc2; + _Alloc2 __a2; + __try + { + _M_pi = __a2.allocate(1); + ::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d); + } + __catch(...) + { + __d(__p); // Call _Deleter on __p. + if (_M_pi) + __a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1); + __throw_exception_again; + } + } + + template<typename _Ptr, typename _Deleter, typename _Alloc> + __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0) + { + typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type; + typedef typename _Alloc::template rebind<_Sp_cd_type>::other _Alloc2; + _Alloc2 __a2(__a); + __try + { + _M_pi = __a2.allocate(1); + ::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d, __a); + } + __catch(...) + { + __d(__p); // Call _Deleter on __p. + if (_M_pi) + __a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1); + __throw_exception_again; + } + } + + template<typename _Tp, typename _Alloc, typename... _Args> + __shared_count(_Sp_make_shared_tag, _Tp*, const _Alloc& __a, + _Args&&... __args) + : _M_pi(0) + { + typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type; + typedef typename _Alloc::template rebind<_Sp_cp_type>::other _Alloc2; + _Alloc2 __a2(__a); + __try + { + _M_pi = __a2.allocate(1); + ::new(static_cast<void*>(_M_pi)) _Sp_cp_type(__a, + std::forward<_Args>(__args)...); + } + __catch(...) + { + if (_M_pi) + __a2.deallocate(static_cast<_Sp_cp_type*>(_M_pi), 1); + __throw_exception_again; + } + } + +#if _GLIBCXX_USE_DEPRECATED + // Special case for auto_ptr<_Tp> to provide the strong guarantee. + template<typename _Tp> + explicit + __shared_count(std::auto_ptr<_Tp>&& __r) + : _M_pi(new _Sp_counted_ptr<_Tp*, _Lp>(__r.get())) + { __r.release(); } +#endif + + // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee. + template<typename _Tp, typename _Del> + explicit + __shared_count(std::unique_ptr<_Tp, _Del>&& __r) + : _M_pi(_S_create_from_up(std::move(__r))) + { __r.release(); } + + // Throw bad_weak_ptr when __r._M_get_use_count() == 0. + explicit __shared_count(const __weak_count<_Lp>& __r); + + ~__shared_count() // nothrow + { + if (_M_pi != 0) + _M_pi->_M_release(); + } + + __shared_count(const __shared_count& __r) + : _M_pi(__r._M_pi) // nothrow + { + if (_M_pi != 0) + _M_pi->_M_add_ref_copy(); + } + + __shared_count& + operator=(const __shared_count& __r) // nothrow + { + _Sp_counted_base<_Lp>* __tmp = __r._M_pi; + if (__tmp != _M_pi) + { + if (__tmp != 0) + __tmp->_M_add_ref_copy(); + if (_M_pi != 0) + _M_pi->_M_release(); + _M_pi = __tmp; + } + return *this; + } + + void + _M_swap(__shared_count& __r) // nothrow + { + _Sp_counted_base<_Lp>* __tmp = __r._M_pi; + __r._M_pi = _M_pi; + _M_pi = __tmp; + } + + long + _M_get_use_count() const // nothrow + { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; } + + bool + _M_unique() const // nothrow + { return this->_M_get_use_count() == 1; } + + void* + _M_get_deleter(const std::type_info& __ti) const + { return _M_pi ? _M_pi->_M_get_deleter(__ti) : 0; } + + bool + _M_less(const __shared_count& __rhs) const + { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } + + bool + _M_less(const __weak_count<_Lp>& __rhs) const + { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } + + // Friend function injected into enclosing namespace and found by ADL + friend inline bool + operator==(const __shared_count& __a, const __shared_count& __b) + { return __a._M_pi == __b._M_pi; } + + private: + friend class __weak_count<_Lp>; + + template<typename _Tp, typename _Del> + static _Sp_counted_base<_Lp>* + _S_create_from_up(std::unique_ptr<_Tp, _Del>&& __r, + typename std::enable_if<!std::is_reference<_Del>::value>::type* = 0) + { + return new _Sp_counted_deleter<_Tp*, _Del, std::allocator<_Tp>, + _Lp>(__r.get(), __r.get_deleter()); + } + + template<typename _Tp, typename _Del> + static _Sp_counted_base<_Lp>* + _S_create_from_up(std::unique_ptr<_Tp, _Del>&& __r, + typename std::enable_if<std::is_reference<_Del>::value>::type* = 0) + { + typedef typename std::remove_reference<_Del>::type _Del1; + typedef std::reference_wrapper<_Del1> _Del2; + return new _Sp_counted_deleter<_Tp*, _Del2, std::allocator<_Tp>, + _Lp>(__r.get(), std::ref(__r.get_deleter())); + } + + _Sp_counted_base<_Lp>* _M_pi; + }; + + + template<_Lock_policy _Lp> + class __weak_count + { + public: + constexpr __weak_count() : _M_pi(0) // nothrow + { } + + __weak_count(const __shared_count<_Lp>& __r) : _M_pi(__r._M_pi) // nothrow + { + if (_M_pi != 0) + _M_pi->_M_weak_add_ref(); + } + + __weak_count(const __weak_count<_Lp>& __r) : _M_pi(__r._M_pi) // nothrow + { + if (_M_pi != 0) + _M_pi->_M_weak_add_ref(); + } + + ~__weak_count() // nothrow + { + if (_M_pi != 0) + _M_pi->_M_weak_release(); + } + + __weak_count<_Lp>& + operator=(const __shared_count<_Lp>& __r) // nothrow + { + _Sp_counted_base<_Lp>* __tmp = __r._M_pi; + if (__tmp != 0) + __tmp->_M_weak_add_ref(); + if (_M_pi != 0) + _M_pi->_M_weak_release(); + _M_pi = __tmp; + return *this; + } + + __weak_count<_Lp>& + operator=(const __weak_count<_Lp>& __r) // nothrow + { + _Sp_counted_base<_Lp>* __tmp = __r._M_pi; + if (__tmp != 0) + __tmp->_M_weak_add_ref(); + if (_M_pi != 0) + _M_pi->_M_weak_release(); + _M_pi = __tmp; + return *this; + } + + void + _M_swap(__weak_count<_Lp>& __r) // nothrow + { + _Sp_counted_base<_Lp>* __tmp = __r._M_pi; + __r._M_pi = _M_pi; + _M_pi = __tmp; + } + + long + _M_get_use_count() const // nothrow + { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; } + + bool + _M_less(const __weak_count& __rhs) const + { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } + + bool + _M_less(const __shared_count<_Lp>& __rhs) const + { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } + + // Friend function injected into enclosing namespace and found by ADL + friend inline bool + operator==(const __weak_count& __a, const __weak_count& __b) + { return __a._M_pi == __b._M_pi; } + + private: + friend class __shared_count<_Lp>; + + _Sp_counted_base<_Lp>* _M_pi; + }; + + // Now that __weak_count is defined we can define this constructor: + template<_Lock_policy _Lp> + inline __shared_count<_Lp>:: __shared_count(const __weak_count<_Lp>& __r) + : _M_pi(__r._M_pi) + { + if (_M_pi != 0) + _M_pi->_M_add_ref_lock(); + else + __throw_bad_weak_ptr(); + } + + + // Support for enable_shared_from_this. + + // Friend of __enable_shared_from_this. + template<_Lock_policy _Lp, typename _Tp1, typename _Tp2> + void + __enable_shared_from_this_helper(const __shared_count<_Lp>&, + const __enable_shared_from_this<_Tp1, + _Lp>*, const _Tp2*); + + // Friend of enable_shared_from_this. + template<typename _Tp1, typename _Tp2> + void + __enable_shared_from_this_helper(const __shared_count<>&, + const enable_shared_from_this<_Tp1>*, + const _Tp2*); + + template<_Lock_policy _Lp> + inline void + __enable_shared_from_this_helper(const __shared_count<_Lp>&, ...) + { } + + + template<typename _Tp, _Lock_policy _Lp> + class __shared_ptr + { + public: + typedef _Tp element_type; + + constexpr __shared_ptr() + : _M_ptr(0), _M_refcount() // never throws + { } + + template<typename _Tp1> + explicit __shared_ptr(_Tp1* __p) + : _M_ptr(__p), _M_refcount(__p) + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + static_assert( sizeof(_Tp1) > 0, "incomplete type" ); + __enable_shared_from_this_helper(_M_refcount, __p, __p); + } + + template<typename _Tp1, typename _Deleter> + __shared_ptr(_Tp1* __p, _Deleter __d) + : _M_ptr(__p), _M_refcount(__p, __d) + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + // TODO requires _Deleter CopyConstructible and __d(__p) well-formed + __enable_shared_from_this_helper(_M_refcount, __p, __p); + } + + template<typename _Tp1, typename _Deleter, typename _Alloc> + __shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a) + : _M_ptr(__p), _M_refcount(__p, __d, std::move(__a)) + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + // TODO requires _Deleter CopyConstructible and __d(__p) well-formed + __enable_shared_from_this_helper(_M_refcount, __p, __p); + } + + template<typename _Deleter> + __shared_ptr(nullptr_t __p, _Deleter __d) + : _M_ptr(0), _M_refcount(__p, __d) + { } + + template<typename _Deleter, typename _Alloc> + __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a) + : _M_ptr(0), _M_refcount(__p, __d, std::move(__a)) + { } + + template<typename _Tp1> + __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, _Tp* __p) + : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws + { } + + __shared_ptr(const __shared_ptr&) = default; // never throws + __shared_ptr& operator=(const __shared_ptr&) = default; // never throws + + template<typename _Tp1, typename = typename + std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> + __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r) + : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws + { } + + __shared_ptr(__shared_ptr&& __r) + : _M_ptr(__r._M_ptr), _M_refcount() // never throws + { + _M_refcount._M_swap(__r._M_refcount); + __r._M_ptr = 0; + } + + template<typename _Tp1, typename = typename + std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> + __shared_ptr(__shared_ptr<_Tp1, _Lp>&& __r) + : _M_ptr(__r._M_ptr), _M_refcount() // never throws + { + _M_refcount._M_swap(__r._M_refcount); + __r._M_ptr = 0; + } + + template<typename _Tp1> + explicit __shared_ptr(const __weak_ptr<_Tp1, _Lp>& __r) + : _M_refcount(__r._M_refcount) // may throw + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + + // It is now safe to copy __r._M_ptr, as + // _M_refcount(__r._M_refcount) did not throw. + _M_ptr = __r._M_ptr; + } + + // If an exception is thrown this constructor has no effect. + template<typename _Tp1, typename _Del> + __shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r) + : _M_ptr(__r.get()), _M_refcount() + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + _Tp1* __tmp = __r.get(); + _M_refcount = __shared_count<_Lp>(std::move(__r)); + __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp); + } + +#if _GLIBCXX_USE_DEPRECATED + // Postcondition: use_count() == 1 and __r.get() == 0 + template<typename _Tp1> + __shared_ptr(std::auto_ptr<_Tp1>&& __r) + : _M_ptr(__r.get()), _M_refcount() + { + __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) + static_assert( sizeof(_Tp1) > 0, "incomplete type" ); + _Tp1* __tmp = __r.get(); + _M_refcount = __shared_count<_Lp>(std::move(__r)); + __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp); + } +#endif + + /* TODO: use delegating constructor */ + constexpr __shared_ptr(nullptr_t) + : _M_ptr(0), _M_refcount() // never throws + { } + + template<typename _Tp1> + __shared_ptr& + operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws + { + _M_ptr = __r._M_ptr; + _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw + return *this; + } + +#if _GLIBCXX_USE_DEPRECATED + template<typename _Tp1> + __shared_ptr& + operator=(std::auto_ptr<_Tp1>&& __r) + { + __shared_ptr(std::move(__r)).swap(*this); + return *this; + } +#endif + + __shared_ptr& + operator=(__shared_ptr&& __r) + { + __shared_ptr(std::move(__r)).swap(*this); + return *this; + } + + template<class _Tp1> + __shared_ptr& + operator=(__shared_ptr<_Tp1, _Lp>&& __r) + { + __shared_ptr(std::move(__r)).swap(*this); + return *this; + } + + template<typename _Tp1, typename _Del> + __shared_ptr& + operator=(std::unique_ptr<_Tp1, _Del>&& __r) + { + __shared_ptr(std::move(__r)).swap(*this); + return *this; + } + + void + reset() // never throws + { __shared_ptr().swap(*this); } + + template<typename _Tp1> + void + reset(_Tp1* __p) // _Tp1 must be complete. + { + // Catch self-reset errors. + _GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr); + __shared_ptr(__p).swap(*this); + } + + template<typename _Tp1, typename _Deleter> + void + reset(_Tp1* __p, _Deleter __d) + { __shared_ptr(__p, __d).swap(*this); } + + template<typename _Tp1, typename _Deleter, typename _Alloc> + void + reset(_Tp1* __p, _Deleter __d, _Alloc __a) + { __shared_ptr(__p, __d, std::move(__a)).swap(*this); } + + // Allow class instantiation when _Tp is [cv-qual] void. + typename std::add_lvalue_reference<_Tp>::type + operator*() const // never throws + { + _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); + return *_M_ptr; + } + + _Tp* + operator->() const // never throws + { + _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); + return _M_ptr; + } + + _Tp* + get() const // never throws + { return _M_ptr; } + + explicit operator bool() const // never throws + { return _M_ptr == 0 ? false : true; } + + bool + unique() const // never throws + { return _M_refcount._M_unique(); } + + long + use_count() const // never throws + { return _M_refcount._M_get_use_count(); } + + void + swap(__shared_ptr<_Tp, _Lp>& __other) // never throws + { + std::swap(_M_ptr, __other._M_ptr); + _M_refcount._M_swap(__other._M_refcount); + } + + template<typename _Tp1> + bool + owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const + { return _M_refcount._M_less(__rhs._M_refcount); } + + template<typename _Tp1> + bool + owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const + { return _M_refcount._M_less(__rhs._M_refcount); } + +#ifdef __GXX_RTTI + protected: + // 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) + : _M_ptr(), _M_refcount(__tag, (_Tp*)0, __a, + std::forward<_Args>(__args)...) + { + // _M_ptr needs to point to the newly constructed object. + // This relies on _Sp_counted_ptr_inplace::_M_get_deleter. + void* __p = _M_refcount._M_get_deleter(typeid(__tag)); + _M_ptr = static_cast<_Tp*>(__p); + __enable_shared_from_this_helper(_M_refcount, _M_ptr, _M_ptr); + } +#else + template<typename _Alloc> + struct _Deleter + { + void operator()(_Tp* __ptr) + { + _M_alloc.destroy(__ptr); + _M_alloc.deallocate(__ptr, 1); + } + _Alloc _M_alloc; + }; + + template<typename _Alloc, typename... _Args> + __shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a, + _Args&&... __args) + : _M_ptr(), _M_refcount() + { + typedef typename _Alloc::template rebind<_Tp>::other _Alloc2; + _Deleter<_Alloc2> __del = { _Alloc2(__a) }; + _M_ptr = __del._M_alloc.allocate(1); + __try + { + __del._M_alloc.construct(_M_ptr, std::forward<_Args>(__args)...); + } + __catch(...) + { + __del._M_alloc.deallocate(_M_ptr, 1); + __throw_exception_again; + } + __shared_count<_Lp> __count(_M_ptr, __del, __del._M_alloc); + _M_refcount._M_swap(__count); + __enable_shared_from_this_helper(_M_refcount, _M_ptr, _M_ptr); + } +#endif + + template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc, + typename... _Args> + friend __shared_ptr<_Tp1, _Lp1> + __allocate_shared(const _Alloc& __a, _Args&&... __args); + + private: + void* + _M_get_deleter(const std::type_info& __ti) const + { return _M_refcount._M_get_deleter(__ti); } + + template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; + template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; + + template<typename _Del, typename _Tp1, _Lock_policy _Lp1> + friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&); + + _Tp* _M_ptr; // Contained pointer. + __shared_count<_Lp> _M_refcount; // Reference counter. + }; + + + // 20.8.13.2.7 shared_ptr comparisons + template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> + inline bool + operator==(const __shared_ptr<_Tp1, _Lp>& __a, + const __shared_ptr<_Tp2, _Lp>& __b) + { return __a.get() == __b.get(); } + + template<typename _Tp, _Lock_policy _Lp> + inline bool + operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) + { return __a.get() == nullptr; } + + template<typename _Tp, _Lock_policy _Lp> + inline bool + operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __b) + { return nullptr == __b.get(); } + + template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> + inline bool + operator!=(const __shared_ptr<_Tp1, _Lp>& __a, + const __shared_ptr<_Tp2, _Lp>& __b) + { return __a.get() != __b.get(); } + + template<typename _Tp, _Lock_policy _Lp> + inline bool + operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) + { return __a.get() != nullptr; } + + template<typename _Tp, _Lock_policy _Lp> + inline bool + operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __b) + { return nullptr != __b.get(); } + + template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> + inline bool + operator<(const __shared_ptr<_Tp1, _Lp>& __a, + const __shared_ptr<_Tp2, _Lp>& __b) + { return __a.get() < __b.get(); } + + template<typename _Sp> + struct _Sp_less : public binary_function<_Sp, _Sp, bool> + { + bool + operator()(const _Sp& __lhs, const _Sp& __rhs) const + { + typedef typename _Sp::element_type element_type; + return std::less<element_type*>()(__lhs.get(), __rhs.get()); + } + }; + + template<typename _Tp, _Lock_policy _Lp> + struct less<__shared_ptr<_Tp, _Lp>> + : public _Sp_less<__shared_ptr<_Tp, _Lp>> + { }; + + // 2.2.3.8 shared_ptr specialized algorithms. + template<typename _Tp, _Lock_policy _Lp> + inline void + swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) + { __a.swap(__b); } + + // 2.2.3.9 shared_ptr casts + + // The seemingly equivalent code: + // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get())) + // will eventually result in undefined behaviour, attempting to + // delete the same object twice. + /// static_pointer_cast + template<typename _Tp, typename _Tp1, _Lock_policy _Lp> + inline __shared_ptr<_Tp, _Lp> + static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) + { return __shared_ptr<_Tp, _Lp>(__r, static_cast<_Tp*>(__r.get())); } + + // The seemingly equivalent code: + // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get())) + // will eventually result in undefined behaviour, attempting to + // delete the same object twice. + /// const_pointer_cast + template<typename _Tp, typename _Tp1, _Lock_policy _Lp> + inline __shared_ptr<_Tp, _Lp> + const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) + { return __shared_ptr<_Tp, _Lp>(__r, const_cast<_Tp*>(__r.get())); } + + // The seemingly equivalent code: + // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get())) + // will eventually result in undefined behaviour, attempting to + // delete the same object twice. + /// dynamic_pointer_cast + template<typename _Tp, typename _Tp1, _Lock_policy _Lp> + inline __shared_ptr<_Tp, _Lp> + dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) + { + if (_Tp* __p = dynamic_cast<_Tp*>(__r.get())) + return __shared_ptr<_Tp, _Lp>(__r, __p); + return __shared_ptr<_Tp, _Lp>(); + } + + + template<typename _Tp, _Lock_policy _Lp> + class __weak_ptr + { + public: + typedef _Tp element_type; + + constexpr __weak_ptr() + : _M_ptr(0), _M_refcount() // never throws + { } + + // Generated copy constructor, assignment, destructor are fine. + + // The "obvious" converting constructor implementation: + // + // template<typename _Tp1> + // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r) + // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws + // { } + // + // has a serious problem. + // + // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr) + // conversion may require access to *__r._M_ptr (virtual inheritance). + // + // It is not possible to avoid spurious access violations since + // in multithreaded programs __r._M_ptr may be invalidated at any point. + template<typename _Tp1, typename = typename + std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> + __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r) + : _M_refcount(__r._M_refcount) // never throws + { _M_ptr = __r.lock().get(); } + + template<typename _Tp1, typename = typename + std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> + __weak_ptr(const __shared_ptr<_Tp1, _Lp>& __r) + : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws + { } + + template<typename _Tp1> + __weak_ptr& + operator=(const __weak_ptr<_Tp1, _Lp>& __r) // never throws + { + _M_ptr = __r.lock().get(); + _M_refcount = __r._M_refcount; + return *this; + } + + template<typename _Tp1> + __weak_ptr& + operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws + { + _M_ptr = __r._M_ptr; + _M_refcount = __r._M_refcount; + return *this; + } + + __shared_ptr<_Tp, _Lp> + lock() const // never throws + { +#ifdef __GTHREADS + // Optimization: avoid throw overhead. + if (expired()) + return __shared_ptr<element_type, _Lp>(); + + __try + { + return __shared_ptr<element_type, _Lp>(*this); + } + __catch(const bad_weak_ptr&) + { + // Q: How can we get here? + // A: Another thread may have invalidated r after the + // use_count test above. + return __shared_ptr<element_type, _Lp>(); + } + +#else + // Optimization: avoid try/catch overhead when single threaded. + return expired() ? __shared_ptr<element_type, _Lp>() + : __shared_ptr<element_type, _Lp>(*this); + +#endif + } // XXX MT + + long + use_count() const // never throws + { return _M_refcount._M_get_use_count(); } + + bool + expired() const // never throws + { return _M_refcount._M_get_use_count() == 0; } + + template<typename _Tp1> + bool + owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const + { return _M_refcount._M_less(__rhs._M_refcount); } + + template<typename _Tp1> + bool + owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const + { return _M_refcount._M_less(__rhs._M_refcount); } + + void + reset() // never throws + { __weak_ptr().swap(*this); } + + void + swap(__weak_ptr& __s) // never throws + { + std::swap(_M_ptr, __s._M_ptr); + _M_refcount._M_swap(__s._M_refcount); + } + + private: + // Used by __enable_shared_from_this. + void + _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) + { + _M_ptr = __ptr; + _M_refcount = __refcount; + } + + template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; + template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; + friend class __enable_shared_from_this<_Tp, _Lp>; + friend class enable_shared_from_this<_Tp>; + + _Tp* _M_ptr; // Contained pointer. + __weak_count<_Lp> _M_refcount; // Reference counter. + }; + + // 20.8.13.3.7 weak_ptr specialized algorithms. + template<typename _Tp, _Lock_policy _Lp> + inline void + swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) + { __a.swap(__b); } + + template<typename _Tp, typename _Tp1> + struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool> + { + bool + operator()(const _Tp& __lhs, const _Tp& __rhs) const + { return __lhs.owner_before(__rhs); } + + bool + operator()(const _Tp& __lhs, const _Tp1& __rhs) const + { return __lhs.owner_before(__rhs); } + + bool + operator()(const _Tp1& __lhs, const _Tp& __rhs) const + { return __lhs.owner_before(__rhs); } + }; + + template<typename _Tp, _Lock_policy _Lp> + struct owner_less<__shared_ptr<_Tp, _Lp>> + : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>> + { }; + + template<typename _Tp, _Lock_policy _Lp> + struct owner_less<__weak_ptr<_Tp, _Lp>> + : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>> + { }; + + + template<typename _Tp, _Lock_policy _Lp> + class __enable_shared_from_this + { + protected: + constexpr __enable_shared_from_this() { } + + __enable_shared_from_this(const __enable_shared_from_this&) { } + + __enable_shared_from_this& + operator=(const __enable_shared_from_this&) + { return *this; } + + ~__enable_shared_from_this() { } + + public: + __shared_ptr<_Tp, _Lp> + shared_from_this() + { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); } + + __shared_ptr<const _Tp, _Lp> + shared_from_this() const + { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); } + + private: + template<typename _Tp1> + void + _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const + { _M_weak_this._M_assign(__p, __n); } + + template<typename _Tp1> + friend void + __enable_shared_from_this_helper(const __shared_count<_Lp>& __pn, + const __enable_shared_from_this* __pe, + const _Tp1* __px) + { + if (__pe != 0) + __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn); + } + + mutable __weak_ptr<_Tp, _Lp> _M_weak_this; + }; + + + template<typename _Tp, _Lock_policy _Lp, typename _Alloc, typename... _Args> + inline __shared_ptr<_Tp, _Lp> + __allocate_shared(const _Alloc& __a, _Args&&... __args) + { + return __shared_ptr<_Tp, _Lp>(_Sp_make_shared_tag(), __a, + std::forward<_Args>(__args)...); + } + + template<typename _Tp, _Lock_policy _Lp, typename... _Args> + inline __shared_ptr<_Tp, _Lp> + __make_shared(_Args&&... __args) + { + typedef typename std::remove_const<_Tp>::type _Tp_nc; + return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(), + std::forward<_Args>(__args)...); + } + + /// std::hash specialization for __shared_ptr. + template<typename _Tp, _Lock_policy _Lp> + struct hash<__shared_ptr<_Tp, _Lp>> + : public std::unary_function<__shared_ptr<_Tp, _Lp>, size_t> + { + size_t + operator()(const __shared_ptr<_Tp, _Lp>& __s) const + { return std::hash<_Tp*>()(__s.get()); } + }; + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace + +#endif // _SHARED_PTR_BASE_H |