1179 lines
30 KiB
C++
1179 lines
30 KiB
C++
// <tr1/boost_shared_ptr.h> -*- C++ -*-
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// Copyright (C) 2005 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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// shared_count.hpp
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// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
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// shared_ptr.hpp
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// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
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// Copyright (C) 2001, 2002, 2003 Peter Dimov
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// weak_ptr.hpp
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// Copyright (C) 2001, 2002, 2003 Peter Dimov
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// enable_shared_from_this.hpp
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// Copyright (C) 2002 Peter Dimov
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// GCC Note: based on version 1.32.0 of the Boost library.
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/** @file boost_memory.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*/
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#ifndef _BOOST_SHARED_PTR_H
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#define _BOOST_SHARED_PTR_H 1
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// namespace std::tr1
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namespace std
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{
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_GLIBCXX_BEGIN_NAMESPACE(tr1)
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// TODO This should go into a separate header really.
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enum _Lock_policy { _S_lockfree, _S_mutex, _S_single };
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static const _Lock_policy __shared_ptr_default_lock_mode =
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#ifdef __GTHREADS
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// NOTE: This doesn't actually exist yet in the compiler.
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#ifdef _GLIBCXX_ATOMIC_BUILTINS
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_S_lockfree;
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#else
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_S_mutex;
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#endif
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#else
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_S_single;
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#endif
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// END TODO
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class bad_weak_ptr : public std::exception
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{
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public:
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virtual char const*
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what() const throw()
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{ return "tr1::bad_weak_ptr"; }
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};
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// Helper for exception objects in <tr1/memory>
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// TODO this should be defined in a different file.
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inline void
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__throw_bad_weak_ptr()
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{
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#if __EXCEPTIONS
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throw bad_weak_ptr();
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#else
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std::abort();
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#endif
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}
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template<typename _Tp>
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struct _Sp_deleter
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{
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typedef void result_type;
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typedef _Tp* argument_type;
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void
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operator()(_Tp* p) const
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{ delete p; }
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};
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// Empty helper class except when the template argument is _S_mutex.
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template <_Lock_policy __l>
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class _Mutex_base
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{
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};
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template <>
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class _Mutex_base<_S_mutex>
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{
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public:
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__gnu_cxx::mutex_type _M_mutex;
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_Mutex_base()
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{
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// For the case of __GTHREAD_MUTEX_INIT we haven't initialised
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// the mutex yet, so do it now.
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#if defined(__GTHREADS) && defined(__GTHREAD_MUTEX_INIT)
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__gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
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_M_mutex = __tmp;
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#endif
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}
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};
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template <_Lock_policy __l = __shared_ptr_default_lock_mode>
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class _Sp_counted_base
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: public _Mutex_base<__l>
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{
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public:
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_Sp_counted_base()
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: _M_use_count(1), _M_weak_count(1)
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{
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}
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virtual
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~_Sp_counted_base() // nothrow
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{ }
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// dispose() is called when _M_use_count drops to zero, to release
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// the resources managed by *this.
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virtual void
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dispose() = 0; // nothrow
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// destroy() is called when _M_weak_count drops to zero.
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virtual void
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destroy() // nothrow
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{
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delete this;
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}
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virtual void*
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get_deleter(const std::type_info&) = 0;
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void
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add_ref_copy()
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{
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__gnu_cxx::__atomic_add(&_M_use_count, 1);
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}
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void
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add_ref_lock();
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void
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release() // nothrow
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{
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if (__gnu_cxx::__exchange_and_add(&_M_use_count, -1) == 1)
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{
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dispose();
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#ifdef __GTHREADS
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_GLIBCXX_READ_MEM_BARRIER;
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_GLIBCXX_WRITE_MEM_BARRIER;
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#endif
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if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) == 1)
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destroy();
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}
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}
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void
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weak_add_ref() // nothrow
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{
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__gnu_cxx::__atomic_add(&_M_weak_count, 1);
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}
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void
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weak_release() // nothrow
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{
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if (__gnu_cxx::__exchange_and_add(&_M_weak_count, -1) == 1)
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{
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#ifdef __GTHREADS
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_GLIBCXX_READ_MEM_BARRIER;
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_GLIBCXX_WRITE_MEM_BARRIER;
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#endif
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destroy();
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}
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}
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long
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use_count() const // nothrow
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{
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return _M_use_count; // XXX is this MT safe?
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}
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private:
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_Sp_counted_base(_Sp_counted_base const&);
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_Sp_counted_base& operator=(_Sp_counted_base const&);
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_Atomic_word _M_use_count; // #shared
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_Atomic_word _M_weak_count; // #weak + (#shared != 0)
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};
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template<>
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inline
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void
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_Sp_counted_base<_S_single>::add_ref_lock()
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{
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if (__gnu_cxx::__exchange_and_add(&_M_use_count, 1) == 0)
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{
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_M_use_count = 0;
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__throw_bad_weak_ptr();
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}
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}
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#ifdef __GTHREADS
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template<>
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inline
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void
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_Sp_counted_base<_S_mutex>::add_ref_lock()
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{
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__gnu_cxx::lock lock(_M_mutex);
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if (__gnu_cxx::__exchange_and_add(&_M_use_count, 1) == 0)
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{
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_M_use_count = 0;
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__throw_bad_weak_ptr();
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}
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}
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#endif
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template<>
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inline
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void
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_Sp_counted_base<_S_lockfree>::add_ref_lock()
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{
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// Perform lock-free add-if-not-zero operation.
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_Atomic_word __count;
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do
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{
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__count = _M_use_count;
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if (__count == 0)
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{
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__throw_bad_weak_ptr();
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}
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/* Replace the current counter value with the old value + 1, as long
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* as it's not changed meanwhile. */
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}
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while (!__sync_bool_compare_and_swap(&_M_use_count, __count, __count + 1));
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}
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template<typename _Ptr, typename _Deleter, _Lock_policy __l>
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class _Sp_counted_base_impl
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: public _Sp_counted_base<__l>
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{
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public:
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/**
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* @brief
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* @pre d(p) must not throw.
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*/
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_Sp_counted_base_impl(_Ptr __p, _Deleter __d)
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: _M_ptr(__p), _M_del(__d)
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{ }
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virtual void
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dispose() // nothrow
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{
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_M_del(_M_ptr);
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}
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virtual void*
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get_deleter(const std::type_info& __ti)
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{
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return __ti == typeid(_Deleter) ? &_M_del : 0;
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}
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private:
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_Sp_counted_base_impl(const _Sp_counted_base_impl&);
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_Sp_counted_base_impl& operator=(const _Sp_counted_base_impl&);
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_Ptr _M_ptr; // copy constructor must not throw
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_Deleter _M_del; // copy constructor must not throw
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};
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template<_Lock_policy __l = __shared_ptr_default_lock_mode>
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class weak_count;
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template<_Lock_policy __l = __shared_ptr_default_lock_mode>
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class shared_count
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{
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private:
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_Sp_counted_base<__l>* _M_pi;
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friend class weak_count<__l>;
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public:
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shared_count()
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: _M_pi(0) // nothrow
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{ }
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template<typename _Ptr, typename _Deleter>
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shared_count(_Ptr __p, _Deleter __d)
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: _M_pi(0)
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{
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try
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{
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_M_pi = new _Sp_counted_base_impl<_Ptr, _Deleter, __l>(__p, __d);
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}
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catch(...)
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{
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__d(__p); // delete __p
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__throw_exception_again;
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}
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}
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// auto_ptr<_Tp> is special cased to provide the strong guarantee
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template<typename _Tp>
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explicit shared_count(std::auto_ptr<_Tp>& __r)
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: _M_pi(new _Sp_counted_base_impl<_Tp*,
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_Sp_deleter<_Tp>, __l >(__r.get(), _Sp_deleter<_Tp>()))
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{ __r.release(); }
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// throws bad_weak_ptr when __r.use_count() == 0
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explicit shared_count(const weak_count<__l>& __r);
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~shared_count() // nothrow
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{
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if (_M_pi != 0)
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_M_pi->release();
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}
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shared_count(const shared_count& __r)
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: _M_pi(__r._M_pi) // nothrow
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{
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if (_M_pi != 0)
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_M_pi->add_ref_copy();
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}
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shared_count&
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operator=(const shared_count& __r) // nothrow
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{
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_Sp_counted_base<__l>* __tmp = __r._M_pi;
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if(__tmp != _M_pi)
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{
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if(__tmp != 0)
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__tmp->add_ref_copy();
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if(_M_pi != 0)
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_M_pi->release();
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_M_pi = __tmp;
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}
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return *this;
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}
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void swap(shared_count& __r) // nothrow
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{
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_Sp_counted_base<__l>* __tmp = __r._M_pi;
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__r._M_pi = _M_pi;
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_M_pi = __tmp;
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}
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long
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use_count() const // nothrow
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{ return _M_pi != 0 ? _M_pi->use_count() : 0; }
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bool
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unique() const // nothrow
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{ return this->use_count() == 1; }
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friend inline bool
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operator==(const shared_count& __a, const shared_count& __b)
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{ return __a._M_pi == __b._M_pi; }
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friend inline bool
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operator<(const shared_count& __a, const shared_count& __b)
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{ return std::less<_Sp_counted_base<__l>*>()(__a._M_pi, __b._M_pi); }
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void*
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get_deleter(const std::type_info& __ti) const
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{ return _M_pi ? _M_pi->get_deleter(__ti) : 0; }
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};
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template<_Lock_policy __l>
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class weak_count
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{
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private:
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_Sp_counted_base<__l>* _M_pi;
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friend class shared_count<__l>;
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public:
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weak_count()
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: _M_pi(0) // nothrow
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{ }
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weak_count(const shared_count<__l>& __r)
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: _M_pi(__r._M_pi) // nothrow
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{
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if (_M_pi != 0)
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_M_pi->weak_add_ref();
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}
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weak_count(const weak_count<__l>& __r)
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: _M_pi(__r._M_pi) // nothrow
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{
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if (_M_pi != 0)
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_M_pi->weak_add_ref();
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}
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~weak_count() // nothrow
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{
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if (_M_pi != 0)
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_M_pi->weak_release();
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}
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weak_count<__l>&
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operator=(const shared_count<__l>& __r) // nothrow
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{
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_Sp_counted_base<__l>* __tmp = __r._M_pi;
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if (__tmp != 0)
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__tmp->weak_add_ref();
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if (_M_pi != 0)
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_M_pi->weak_release();
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_M_pi = __tmp;
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return *this;
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}
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weak_count<__l>&
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operator=(const weak_count<__l>& __r) // nothrow
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{
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_Sp_counted_base<__l> * __tmp = __r._M_pi;
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if (__tmp != 0)
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__tmp->weak_add_ref();
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if (_M_pi != 0)
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_M_pi->weak_release();
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_M_pi = __tmp;
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return *this;
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}
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void
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swap(weak_count<__l>& __r) // nothrow
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{
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_Sp_counted_base<__l> * __tmp = __r._M_pi;
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__r._M_pi = _M_pi;
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_M_pi = __tmp;
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}
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long
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use_count() const // nothrow
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{ return _M_pi != 0 ? _M_pi->use_count() : 0; }
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friend inline bool
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operator==(const weak_count<__l>& __a, const weak_count<__l>& __b)
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{ return __a._M_pi == __b._M_pi; }
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friend inline bool
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operator<(const weak_count<__l>& __a, const weak_count<__l>& __b)
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{ return std::less<_Sp_counted_base<__l>*>()(__a._M_pi, __b._M_pi); }
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};
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template<_Lock_policy __l>
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inline
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shared_count<__l>::shared_count(const weak_count<__l>& __r)
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: _M_pi(__r._M_pi)
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{
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if (_M_pi != 0)
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_M_pi->add_ref_lock();
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else
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__throw_bad_weak_ptr();
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}
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// fwd decls
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template<typename _Tp, _Lock_policy __l = __shared_ptr_default_lock_mode>
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class __shared_ptr;
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template<typename _Tp, _Lock_policy __l = __shared_ptr_default_lock_mode>
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class __weak_ptr;
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template<typename _Tp, _Lock_policy __l>
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class __enable_shared_from_this;
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struct __static_cast_tag {};
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struct __const_cast_tag {};
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struct __dynamic_cast_tag {};
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struct __polymorphic_cast_tag {};
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template<class _Tp>
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struct shared_ptr_traits
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{ typedef _Tp& reference; };
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template<>
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struct shared_ptr_traits<void>
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{ typedef void reference; };
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template<>
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struct shared_ptr_traits<void const>
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{ typedef void reference; };
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template<>
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struct shared_ptr_traits<void volatile>
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{ typedef void reference; };
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template<>
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struct shared_ptr_traits<void const volatile>
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{ typedef void reference; };
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// enable_shared_from_this support
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// friend of __enable_shared_from_this
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template<_Lock_policy __l, typename _Tp1, typename _Tp2>
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void
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__enable_shared_from_this_helper(const shared_count<__l>& __pn,
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const __enable_shared_from_this<_Tp1, __l>* __pe,
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const _Tp2* __px );
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template<_Lock_policy __l>
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inline void
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__enable_shared_from_this_helper(const shared_count<__l>&, ...)
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{ }
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// get_deleter must be declared before friend declaration by shared_ptr.
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template<typename _Del, typename _Tp, _Lock_policy __l>
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_Del* get_deleter(const __shared_ptr<_Tp, __l>&);
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|
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/**
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* @class shared_ptr <tr1/memory>
|
|
*
|
|
* A smart pointer with reference-counted copy semantics.
|
|
* The object pointed to is deleted when the last shared_ptr pointing to it
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* is destroyed or reset.
|
|
*/
|
|
template<typename _Tp, _Lock_policy __l>
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|
class __shared_ptr
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{
|
|
typedef typename shared_ptr_traits<_Tp>::reference _Reference;
|
|
|
|
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, _Sp_deleter<_Tp1>())
|
|
{
|
|
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
|
|
// __glibcxx_function_requires(_CompleteConcept<_Tp1*>)
|
|
|
|
__enable_shared_from_this_helper( _M_refcount, __p, __p );
|
|
}
|
|
|
|
//
|
|
// Requirements: D'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 D is 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()
|
|
* @throw std::bad_alloc, in which case
|
|
*/
|
|
template<typename _Tp1>
|
|
__shared_ptr(const __shared_ptr<_Tp1, __l>& __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, __l>& __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;
|
|
}
|
|
|
|
/**
|
|
* @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()
|
|
{
|
|
// TODO requires r.release() convertible to _Tp*, Tp1 is complete,
|
|
// delete r.release() well-formed
|
|
_Tp1 * __tmp = __r.get();
|
|
_M_refcount = shared_count<__l>(__r);
|
|
|
|
__enable_shared_from_this_helper( _M_refcount, __tmp, __tmp );
|
|
}
|
|
|
|
template<typename _Tp1>
|
|
__shared_ptr(const __shared_ptr<_Tp1, __l>& __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, __l>& __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, __l>& __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<__l>();
|
|
}
|
|
|
|
template<typename _Tp1>
|
|
__shared_ptr&
|
|
operator=(const __shared_ptr<_Tp1, __l>& __r) // never throws
|
|
{
|
|
_M_ptr = __r._M_ptr;
|
|
_M_refcount = __r._M_refcount; // shared_count::op= doesn't throw
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Tp1>
|
|
__shared_ptr&
|
|
operator=(std::auto_ptr<_Tp1>& __r)
|
|
{
|
|
__shared_ptr(__r).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
void
|
|
reset() // never throws
|
|
{ __shared_ptr().swap(*this); }
|
|
|
|
template<typename _Tp1>
|
|
void
|
|
reset(_Tp1* __p) // _Tp1 must be complete
|
|
{
|
|
_GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr); // catch self-reset
|
|
// errors
|
|
__shared_ptr(__p).swap(*this);
|
|
}
|
|
|
|
template<typename _Tp1, typename _Deleter>
|
|
void
|
|
reset(_Tp1 * __p, _Deleter __d)
|
|
{ __shared_ptr(__p, __d).swap(*this); }
|
|
|
|
// error to instantiate if _Tp is [cv-qual] void
|
|
_Reference
|
|
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.unique(); }
|
|
|
|
long
|
|
use_count() const // never throws
|
|
{ return _M_refcount.use_count(); }
|
|
|
|
void
|
|
swap(__shared_ptr<_Tp, __l>& __other) // never throws
|
|
{
|
|
std::swap(_M_ptr, __other._M_ptr);
|
|
_M_refcount.swap(__other._M_refcount);
|
|
}
|
|
|
|
private:
|
|
void*
|
|
_M_get_deleter(const std::type_info& __ti) const
|
|
{ return _M_refcount.get_deleter(__ti); }
|
|
|
|
template<typename _Tp1, _Lock_policy __l1>
|
|
bool
|
|
_M_less(const __shared_ptr<_Tp1, __l1>& __rhs) const
|
|
{ return _M_refcount < __rhs._M_refcount; }
|
|
|
|
template<typename _Tp1, _Lock_policy __l1> friend class __shared_ptr;
|
|
template<typename _Tp1, _Lock_policy __l1> friend class __weak_ptr;
|
|
|
|
template<typename _Del, typename _Tp1, _Lock_policy __l1>
|
|
friend _Del* get_deleter(const __shared_ptr<_Tp1, __l1>&);
|
|
|
|
// friends injected into enclosing namespace and found by ADL:
|
|
template<typename _Tp1>
|
|
friend inline bool
|
|
operator==(const __shared_ptr& __a, const __shared_ptr<_Tp1, __l>& __b)
|
|
{ return __a.get() == __b.get(); }
|
|
|
|
template<typename _Tp1>
|
|
friend inline bool
|
|
operator!=(const __shared_ptr& __a, const __shared_ptr<_Tp1, __l>& __b)
|
|
{ return __a.get() != __b.get(); }
|
|
|
|
template<typename _Tp1>
|
|
friend inline bool
|
|
operator<(const __shared_ptr& __a, const __shared_ptr<_Tp1, __l>& __b)
|
|
{ return __a._M_less(__b); }
|
|
|
|
_Tp* _M_ptr; // contained pointer
|
|
shared_count<__l> _M_refcount; // reference counter
|
|
}; // __shared_ptr
|
|
|
|
// 2.2.3.8 shared_ptr specialized algorithms.
|
|
template<typename _Tp, _Lock_policy __l>
|
|
inline void
|
|
swap(__shared_ptr<_Tp, __l>& __a, __shared_ptr<_Tp, __l>& __b)
|
|
{ __a.swap(__b); }
|
|
|
|
// 2.2.3.9 shared_ptr casts
|
|
/** @warning The seemingly equivalent
|
|
* <code>shared_ptr<T>(static_cast<T*>(r.get()))</code>
|
|
* will eventually result in undefined behaviour,
|
|
* attempting to delete the same object twice.
|
|
*/
|
|
template<typename _Tp, typename _Tp1, _Lock_policy __l>
|
|
__shared_ptr<_Tp, __l>
|
|
static_pointer_cast(const __shared_ptr<_Tp1, __l>& __r)
|
|
{
|
|
return __shared_ptr<_Tp, __l>(__r, __static_cast_tag());
|
|
}
|
|
|
|
/** @warning The seemingly equivalent
|
|
* <code>shared_ptr<T>(const_cast<T*>(r.get()))</code>
|
|
* will eventually result in undefined behaviour,
|
|
* attempting to delete the same object twice.
|
|
*/
|
|
template<typename _Tp, typename _Tp1, _Lock_policy __l>
|
|
__shared_ptr<_Tp, __l>
|
|
const_pointer_cast(const __shared_ptr<_Tp1, __l>& __r)
|
|
{
|
|
return __shared_ptr<_Tp, __l>(__r, __const_cast_tag());
|
|
}
|
|
|
|
/** @warning The seemingly equivalent
|
|
* <code>shared_ptr<T>(dynamic_cast<T*>(r.get()))</code>
|
|
* will eventually result in undefined behaviour,
|
|
* attempting to delete the same object twice.
|
|
*/
|
|
template<typename _Tp, typename _Tp1, _Lock_policy __l>
|
|
__shared_ptr<_Tp, __l>
|
|
dynamic_pointer_cast(const __shared_ptr<_Tp1, __l>& __r)
|
|
{
|
|
return __shared_ptr<_Tp, __l>(__r, __dynamic_cast_tag());
|
|
}
|
|
|
|
// 2.2.3.7 shared_ptr I/O
|
|
template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy __l>
|
|
std::basic_ostream<_Ch, _Tr>&
|
|
operator<<(std::basic_ostream<_Ch, _Tr>& __os, const __shared_ptr<_Tp, __l>& __p)
|
|
{
|
|
__os << __p.get();
|
|
return __os;
|
|
}
|
|
|
|
// 2.2.3.10 shared_ptr get_deleter (experimental)
|
|
template<typename _Del, typename _Tp, _Lock_policy __l>
|
|
inline _Del*
|
|
get_deleter(const __shared_ptr<_Tp, __l>& __p)
|
|
{ return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); }
|
|
|
|
|
|
template<typename _Tp, _Lock_policy __l>
|
|
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<class Y>
|
|
// __weak_ptr(__weak_ptr<Y> const & 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, __l>& 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, __l>& 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, __l>& 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, __l>& r) // never throws
|
|
{
|
|
_M_ptr = r._M_ptr;
|
|
_M_refcount = r._M_refcount;
|
|
return *this;
|
|
}
|
|
|
|
__shared_ptr<_Tp, __l>
|
|
lock() const // never throws
|
|
{
|
|
#ifdef __GTHREADS
|
|
|
|
// optimization: avoid throw overhead
|
|
if (expired())
|
|
return __shared_ptr<element_type, __l>();
|
|
|
|
try
|
|
{
|
|
return __shared_ptr<element_type, __l>(*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>();
|
|
}
|
|
|
|
#else
|
|
|
|
// optimization: avoid try/catch overhead when single threaded
|
|
return expired() ? __shared_ptr<element_type, __l>()
|
|
: __shared_ptr<element_type, __l>(*this);
|
|
|
|
#endif
|
|
} // XXX MT
|
|
|
|
long
|
|
use_count() const // never throws
|
|
{ return _M_refcount.use_count(); }
|
|
|
|
bool
|
|
expired() const // never throws
|
|
{ return _M_refcount.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.swap(__s._M_refcount);
|
|
}
|
|
|
|
private:
|
|
|
|
template<typename _Tp1>
|
|
bool
|
|
_M_less(const __weak_ptr<_Tp1, __l>& __rhs) const
|
|
{ return _M_refcount < __rhs._M_refcount; }
|
|
|
|
// used by __enable_shared_from_this
|
|
void
|
|
_M_assign(_Tp* __ptr, const shared_count<__l>& __refcount)
|
|
{
|
|
_M_ptr = __ptr;
|
|
_M_refcount = __refcount;
|
|
}
|
|
|
|
// friend injected into namespace and found by ADL
|
|
|
|
template<typename _Tp1>
|
|
friend inline bool
|
|
operator<(const __weak_ptr& __lhs, const __weak_ptr<_Tp1, __l>& __rhs)
|
|
{ return __lhs._M_less(__rhs); }
|
|
|
|
template<typename _Tp1, _Lock_policy __l1> friend class __weak_ptr;
|
|
template<typename _Tp1, _Lock_policy __l1> friend class __shared_ptr;
|
|
friend class __enable_shared_from_this<_Tp, __l>;
|
|
|
|
_Tp* _M_ptr; // contained pointer
|
|
weak_count<__l> _M_refcount; // reference counter
|
|
|
|
}; // __weak_ptr
|
|
|
|
// 2.2.4.7 weak_ptr specialized algorithms.
|
|
template<typename _Tp, _Lock_policy __l>
|
|
void
|
|
swap(__weak_ptr<_Tp, __l>& __a, __weak_ptr<_Tp, __l>& __b)
|
|
{ __a.swap(__b); }
|
|
|
|
|
|
template<typename _Tp, _Lock_policy __l = __shared_ptr_default_lock_mode>
|
|
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, __l>
|
|
shared_from_this()
|
|
{
|
|
__shared_ptr<_Tp, __l> __p(this->_M_weak_this);
|
|
return __p;
|
|
}
|
|
|
|
__shared_ptr<const _Tp, __l>
|
|
shared_from_this() const
|
|
{
|
|
__shared_ptr<const _Tp, __l> __p(this->_M_weak_this);
|
|
return __p;
|
|
}
|
|
|
|
private:
|
|
template<typename _Tp1>
|
|
void
|
|
_M_weak_assign(_Tp1* __p, const shared_count<__l>& __n) const
|
|
{ _M_weak_this._M_assign(__p, __n); }
|
|
|
|
template<typename _Tp1>
|
|
friend void
|
|
__enable_shared_from_this_helper(const shared_count<__l>& __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, __l> _M_weak_this;
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class shared_ptr;
|
|
|
|
// The actual TR1 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;
|
|
}
|
|
};
|
|
|
|
// The actual TR1 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)
|
|
{ }
|
|
|
|
template<typename _Tp1>
|
|
explicit shared_ptr(std::auto_ptr<_Tp1>& __r)
|
|
: __shared_ptr<_Tp>(__r)
|
|
{ }
|
|
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())
|
|
{ }
|
|
// Additional non-base assignment operators to avoid excessive errors.
|
|
template<typename _Tp1>
|
|
shared_ptr&
|
|
operator=(std::auto_ptr<_Tp1>& __r)
|
|
{
|
|
this->__shared_ptr<_Tp>::operator=(__r);
|
|
return *this;
|
|
}
|
|
template<typename _Tp1>
|
|
shared_ptr&
|
|
operator=(const shared_ptr<_Tp1>& __r) // never throws
|
|
{
|
|
this->__shared_ptr<_Tp>::operator=(__r);
|
|
return *this;
|
|
}
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class enable_shared_from_this
|
|
: public __enable_shared_from_this<_Tp>
|
|
{
|
|
protected:
|
|
enable_shared_from_this()
|
|
: __enable_shared_from_this<_Tp>()
|
|
{ }
|
|
|
|
enable_shared_from_this(const enable_shared_from_this&)
|
|
: __enable_shared_from_this<_Tp>(enable_shared_from_this<_Tp>())
|
|
{ }
|
|
};
|
|
|
|
_GLIBCXX_END_NAMESPACE
|
|
} // namespace std
|
|
|
|
#endif
|