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+// <tr1/shared_ptr.h> -*- C++ -*-
+
+// Copyright (C) 2007, 2008, 2009 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/>.
+
+// 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)
+
+// GCC Note: based on version 1.32.0 of the Boost library.
+
+/** @file tr1/shared_ptr.h
+ * This is an internal header file, included by other library headers.
+ * You should not attempt to use it directly.
+ */
+
+#ifndef _TR1_SHARED_PTR_H
+#define _TR1_SHARED_PTR_H 1
+
+#if defined(_GLIBCXX_INCLUDE_AS_CXX0X)
+# error TR1 header cannot be included from C++0x header
+#endif
+
+namespace std
+{
+namespace tr1
+{
+
+ template<typename _Ptr, typename _Deleter, _Lock_policy _Lp>
+ class _Sp_counted_base_impl
+ : public _Sp_counted_base<_Lp>
+ {
+ public:
+ /**
+ * @brief
+ * @pre __d(__p) must not throw.
+ */
+ _Sp_counted_base_impl(_Ptr __p, _Deleter __d)
+ : _M_ptr(__p), _M_del(__d) { }
+
+ virtual void
+ _M_dispose() // nothrow
+ { _M_del(_M_ptr); }
+
+ virtual void*
+ _M_get_deleter(const std::type_info& __ti)
+ { return __ti == typeid(_Deleter) ? &_M_del : 0; }
+
+ private:
+ _Sp_counted_base_impl(const _Sp_counted_base_impl&);
+ _Sp_counted_base_impl& operator=(const _Sp_counted_base_impl&);
+
+ _Ptr _M_ptr; // copy constructor must not throw
+ _Deleter _M_del; // copy constructor must not throw
+ };
+
+ template<_Lock_policy _Lp = __default_lock_policy>
+ class __weak_count;
+
+ template<typename _Tp>
+ struct _Sp_deleter
+ {
+ typedef void result_type;
+ typedef _Tp* argument_type;
+ void operator()(_Tp* __p) const { delete __p; }
+ };
+
+ template<_Lock_policy _Lp = __default_lock_policy>
+ class __shared_count
+ {
+ public:
+ __shared_count()
+ : _M_pi(0) // nothrow
+ { }
+
+ template<typename _Ptr>
+ __shared_count(_Ptr __p) : _M_pi(0)
+ {
+ __try
+ {
+ typedef typename std::tr1::remove_pointer<_Ptr>::type _Tp;
+ _M_pi = new _Sp_counted_base_impl<_Ptr, _Sp_deleter<_Tp>, _Lp>(
+ __p, _Sp_deleter<_Tp>());
+ }
+ __catch(...)
+ {
+ delete __p;
+ __throw_exception_again;
+ }
+ }
+
+ template<typename _Ptr, typename _Deleter>
+ __shared_count(_Ptr __p, _Deleter __d) : _M_pi(0)
+ {
+ __try
+ {
+ _M_pi = new _Sp_counted_base_impl<_Ptr, _Deleter, _Lp>(__p, __d);
+ }
+ __catch(...)
+ {
+ __d(__p); // Call _Deleter on __p.
+ __throw_exception_again;
+ }
+ }
+
+ // 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_base_impl<_Tp*,
+ _Sp_deleter<_Tp>, _Lp >(__r.get(), _Sp_deleter<_Tp>()))
+ { __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; }
+
+ friend inline bool
+ operator==(const __shared_count& __a, const __shared_count& __b)
+ { return __a._M_pi == __b._M_pi; }
+
+ friend inline bool
+ operator<(const __shared_count& __a, const __shared_count& __b)
+ { return std::less<_Sp_counted_base<_Lp>*>()(__a._M_pi, __b._M_pi); }
+
+ void*
+ _M_get_deleter(const std::type_info& __ti) const
+ { return _M_pi ? _M_pi->_M_get_deleter(__ti) : 0; }
+
+ private:
+ friend class __weak_count<_Lp>;
+
+ _Sp_counted_base<_Lp>* _M_pi;
+ };
+
+
+ template<_Lock_policy _Lp>
+ class __weak_count
+ {
+ public:
+ __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; }
+
+ friend inline bool
+ operator==(const __weak_count<_Lp>& __a, const __weak_count<_Lp>& __b)
+ { return __a._M_pi == __b._M_pi; }
+
+ friend inline bool
+ operator<(const __weak_count<_Lp>& __a, const __weak_count<_Lp>& __b)
+ { return std::less<_Sp_counted_base<_Lp>*>()(__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();
+ }
+
+ // 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>
+ class enable_shared_from_this;
+
+ // 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>&, ...)
+ { }
+
+
+ struct __static_cast_tag { };
+ struct __const_cast_tag { };
+ struct __dynamic_cast_tag { };
+
+ /**
+ * @class __shared_ptr
+ *
+ * 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, _Lock_policy _Lp>
+ class __shared_ptr
+ {
+ public:
+ typedef _Tp element_type;
+
+ /** @brief Construct an empty %__shared_ptr.
+ * @post use_count()==0 && get()==0
+ */
+ __shared_ptr()
+ : _M_ptr(0), _M_refcount() // never throws
+ { }
+
+ /** @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)
+ : _M_ptr(__p), _M_refcount(__p)
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ // __glibcxx_function_requires(_CompleteConcept<_Tp1*>)
+ __enable_shared_from_this_helper(_M_refcount, __p, __p);
+ }
+
+ //
+ // Requirements: _Deleter's copy constructor and destructor must
+ // not throw
+ //
+ // __shared_ptr will release __p by calling __d(__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.
+ */
+ 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);
+ }
+
+ // generated copy constructor, assignment, destructor are fine.
+
+ /** @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>
+ __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r)
+ : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
+ { __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) }
+
+ /** @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, _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 !defined(__GXX_EXPERIMENTAL_CXX0X__) || _GLIBCXX_DEPRECATED
+ /**
+ * @post use_count() == 1 and __r.get() == 0
+ */
+ template<typename _Tp1>
+ explicit
+ __shared_ptr(std::auto_ptr<_Tp1>& __r)
+ : _M_ptr(__r.get()), _M_refcount()
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ // TODO requires _Tp1 is complete, delete __r.release() well-formed
+ _Tp1* __tmp = __r.get();
+ _M_refcount = __shared_count<_Lp>(__r);
+ __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp);
+ }
+
+#endif
+
+ template<typename _Tp1>
+ __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, __static_cast_tag)
+ : _M_ptr(static_cast<element_type*>(__r._M_ptr)),
+ _M_refcount(__r._M_refcount)
+ { }
+
+ template<typename _Tp1>
+ __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, __const_cast_tag)
+ : _M_ptr(const_cast<element_type*>(__r._M_ptr)),
+ _M_refcount(__r._M_refcount)
+ { }
+
+ template<typename _Tp1>
+ __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, __dynamic_cast_tag)
+ : _M_ptr(dynamic_cast<element_type*>(__r._M_ptr)),
+ _M_refcount(__r._M_refcount)
+ {
+ if (_M_ptr == 0) // need to allocate new counter -- the cast failed
+ _M_refcount = __shared_count<_Lp>();
+ }
+
+ 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 !defined(__GXX_EXPERIMENTAL_CXX0X__) || _GLIBCXX_DEPRECATED
+ template<typename _Tp1>
+ __shared_ptr&
+ operator=(std::auto_ptr<_Tp1>& __r)
+ {
+ __shared_ptr(__r).swap(*this);
+ return *this;
+ }
+#endif
+
+ 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); }
+
+ // Allow class instantiation when _Tp is [cv-qual] void.
+ typename std::tr1::add_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; }
+
+ // Implicit conversion to "bool"
+ private:
+ typedef _Tp* __shared_ptr::*__unspecified_bool_type;
+
+ public:
+ operator __unspecified_bool_type() const // never throws
+ { return _M_ptr == 0 ? 0 : &__shared_ptr::_M_ptr; }
+
+ 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);
+ }
+
+ private:
+ void*
+ _M_get_deleter(const std::type_info& __ti) const
+ { return _M_refcount._M_get_deleter(__ti); }
+
+ template<typename _Tp1, _Lock_policy _Lp1>
+ bool
+ _M_less(const __shared_ptr<_Tp1, _Lp1>& __rhs) const
+ { return _M_refcount < __rhs._M_refcount; }
+
+ 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>&);
+
+ // Friends injected into enclosing namespace and found by ADL:
+ template<typename _Tp1>
+ friend inline bool
+ operator==(const __shared_ptr& __a, const __shared_ptr<_Tp1, _Lp>& __b)
+ { return __a.get() == __b.get(); }
+
+ template<typename _Tp1>
+ friend inline bool
+ operator!=(const __shared_ptr& __a, const __shared_ptr<_Tp1, _Lp>& __b)
+ { return __a.get() != __b.get(); }
+
+ template<typename _Tp1>
+ friend inline bool
+ operator<(const __shared_ptr& __a, const __shared_ptr<_Tp1, _Lp>& __b)
+ { return __a._M_less(__b); }
+
+ _Tp* _M_ptr; // Contained pointer.
+ __shared_count<_Lp> _M_refcount; // Reference counter.
+ };
+
+ // 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
+ /** @warning The seemingly equivalent
+ * <code>shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))</code>
+ * will eventually result in undefined behaviour,
+ * attempting to delete the same object twice.
+ */
+ 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_tag()); }
+
+ /** @warning The seemingly equivalent
+ * <code>shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))</code>
+ * will eventually result in undefined behaviour,
+ * attempting to delete the same object twice.
+ */
+ 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_tag()); }
+
+ /** @warning The seemingly equivalent
+ * <code>shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))</code>
+ * will eventually result in undefined behaviour,
+ * attempting to delete the same object twice.
+ */
+ template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
+ inline __shared_ptr<_Tp, _Lp>
+ dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
+ { return __shared_ptr<_Tp, _Lp>(__r, __dynamic_cast_tag()); }
+
+ // 2.2.3.7 shared_ptr I/O
+ template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>
+ 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)
+ { return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); }
+
+
+ template<typename _Tp, _Lock_policy _Lp>
+ class __weak_ptr
+ {
+ public:
+ typedef _Tp element_type;
+
+ __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>
+ __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
+ : _M_refcount(__r._M_refcount) // never throws
+ {
+ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
+ _M_ptr = __r.lock().get();
+ }
+
+ template<typename _Tp1>
+ __weak_ptr(const __shared_ptr<_Tp1, _Lp>& __r)
+ : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
+ { __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) }
+
+ 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; }
+
+ 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>
+ bool
+ _M_less(const __weak_ptr<_Tp1, _Lp>& __rhs) const
+ { return _M_refcount < __rhs._M_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>;
+
+ // Friend injected into namespace and found by ADL.
+ template<typename _Tp1>
+ friend inline bool
+ operator<(const __weak_ptr& __lhs, const __weak_ptr<_Tp1, _Lp>& __rhs)
+ { return __lhs._M_less(__rhs); }
+
+ _Tp* _M_ptr; // Contained pointer.
+ __weak_count<_Lp> _M_refcount; // Reference counter.
+ };
+
+ // 2.2.4.7 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, _Lock_policy _Lp>
+ class __enable_shared_from_this
+ {
+ protected:
+ __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;
+ };
+
+
+ /// shared_ptr
+ // The actual shared_ptr, with forwarding constructors and
+ // assignment operators.
+ template<typename _Tp>
+ class shared_ptr
+ : public __shared_ptr<_Tp>
+ {
+ public:
+ shared_ptr()
+ : __shared_ptr<_Tp>() { }
+
+ template<typename _Tp1>
+ explicit
+ shared_ptr(_Tp1* __p)
+ : __shared_ptr<_Tp>(__p) { }
+
+ template<typename _Tp1, typename _Deleter>
+ shared_ptr(_Tp1* __p, _Deleter __d)
+ : __shared_ptr<_Tp>(__p, __d) { }
+
+ template<typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r)
+ : __shared_ptr<_Tp>(__r) { }
+
+ template<typename _Tp1>
+ explicit
+ shared_ptr(const weak_ptr<_Tp1>& __r)
+ : __shared_ptr<_Tp>(__r) { }
+
+#if !defined(__GXX_EXPERIMENTAL_CXX0X__) || _GLIBCXX_DEPRECATED
+ template<typename _Tp1>
+ explicit
+ shared_ptr(std::auto_ptr<_Tp1>& __r)
+ : __shared_ptr<_Tp>(__r) { }
+#endif
+
+ template<typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r, __static_cast_tag)
+ : __shared_ptr<_Tp>(__r, __static_cast_tag()) { }
+
+ template<typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r, __const_cast_tag)
+ : __shared_ptr<_Tp>(__r, __const_cast_tag()) { }
+
+ template<typename _Tp1>
+ shared_ptr(const shared_ptr<_Tp1>& __r, __dynamic_cast_tag)
+ : __shared_ptr<_Tp>(__r, __dynamic_cast_tag()) { }
+
+ template<typename _Tp1>
+ shared_ptr&
+ operator=(const shared_ptr<_Tp1>& __r) // never throws
+ {
+ this->__shared_ptr<_Tp>::operator=(__r);
+ return *this;
+ }
+
+#if !defined(__GXX_EXPERIMENTAL_CXX0X__) || _GLIBCXX_DEPRECATED
+ template<typename _Tp1>
+ shared_ptr&
+ operator=(std::auto_ptr<_Tp1>& __r)
+ {
+ this->__shared_ptr<_Tp>::operator=(__r);
+ return *this;
+ }
+#endif
+ };
+
+ // 2.2.3.8 shared_ptr specialized algorithms.
+ template<typename _Tp>
+ inline void
+ swap(__shared_ptr<_Tp>& __a, __shared_ptr<_Tp>& __b)
+ { __a.swap(__b); }
+
+ template<typename _Tp, typename _Tp1>
+ inline shared_ptr<_Tp>
+ static_pointer_cast(const shared_ptr<_Tp1>& __r)
+ { return shared_ptr<_Tp>(__r, __static_cast_tag()); }
+
+ template<typename _Tp, typename _Tp1>
+ inline shared_ptr<_Tp>
+ const_pointer_cast(const shared_ptr<_Tp1>& __r)
+ { return shared_ptr<_Tp>(__r, __const_cast_tag()); }
+
+ template<typename _Tp, typename _Tp1>
+ inline shared_ptr<_Tp>
+ dynamic_pointer_cast(const shared_ptr<_Tp1>& __r)
+ { return shared_ptr<_Tp>(__r, __dynamic_cast_tag()); }
+
+
+ /// weak_ptr
+ // The actual weak_ptr, with forwarding constructors and
+ // assignment operators.
+ template<typename _Tp>
+ class weak_ptr
+ : public __weak_ptr<_Tp>
+ {
+ public:
+ weak_ptr()
+ : __weak_ptr<_Tp>() { }
+
+ template<typename _Tp1>
+ weak_ptr(const weak_ptr<_Tp1>& __r)
+ : __weak_ptr<_Tp>(__r) { }
+
+ template<typename _Tp1>
+ weak_ptr(const shared_ptr<_Tp1>& __r)
+ : __weak_ptr<_Tp>(__r) { }
+
+ template<typename _Tp1>
+ weak_ptr&
+ operator=(const weak_ptr<_Tp1>& __r) // never throws
+ {
+ this->__weak_ptr<_Tp>::operator=(__r);
+ return *this;
+ }
+
+ template<typename _Tp1>
+ weak_ptr&
+ operator=(const shared_ptr<_Tp1>& __r) // never throws
+ {
+ this->__weak_ptr<_Tp>::operator=(__r);
+ return *this;
+ }
+
+ shared_ptr<_Tp>
+ lock() const // never throws
+ {
+#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
+ }
+ };
+
+ /// enable_shared_from_this
+ template<typename _Tp>
+ class enable_shared_from_this
+ {
+ protected:
+ 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>
+ 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
+ { _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)
+ {
+ if (__pe != 0)
+ __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
+ }
+
+ mutable weak_ptr<_Tp> _M_weak_this;
+ };
+
+}
+}
+
+#endif // _TR1_SHARED_PTR_H