1505 lines
42 KiB
C++
1505 lines
42 KiB
C++
// shared_ptr and weak_ptr implementation details -*- C++ -*-
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// Copyright (C) 2007-2014 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 3, 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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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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// GCC Note: Based on files from version 1.32.0 of the Boost library.
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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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/** @file bits/shared_ptr_base.h
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* This is an internal header file, included by other library headers.
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* Do not attempt to use it directly. @headername{memory}
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*/
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#ifndef _SHARED_PTR_BASE_H
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#define _SHARED_PTR_BASE_H 1
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#include <ext/aligned_buffer.h>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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#if _GLIBCXX_USE_DEPRECATED
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template<typename> class auto_ptr;
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#endif
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/**
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* @brief Exception possibly thrown by @c shared_ptr.
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* @ingroup exceptions
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*/
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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 noexcept;
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virtual ~bad_weak_ptr() noexcept;
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};
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// Substitute for bad_weak_ptr object in the case of -fno-exceptions.
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inline void
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__throw_bad_weak_ptr()
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{ _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); }
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using __gnu_cxx::_Lock_policy;
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using __gnu_cxx::__default_lock_policy;
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using __gnu_cxx::_S_single;
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using __gnu_cxx::_S_mutex;
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using __gnu_cxx::_S_atomic;
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// Empty helper class except when the template argument is _S_mutex.
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template<_Lock_policy _Lp>
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class _Mutex_base
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{
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protected:
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// The atomic policy uses fully-fenced builtins, single doesn't care.
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enum { _S_need_barriers = 0 };
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};
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template<>
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class _Mutex_base<_S_mutex>
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: public __gnu_cxx::__mutex
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{
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protected:
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// This policy is used when atomic builtins are not available.
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// The replacement atomic operations might not have the necessary
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// memory barriers.
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enum { _S_need_barriers = 1 };
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};
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template<_Lock_policy _Lp = __default_lock_policy>
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class _Sp_counted_base
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: public _Mutex_base<_Lp>
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{
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public:
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_Sp_counted_base() noexcept
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: _M_use_count(1), _M_weak_count(1) { }
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virtual
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~_Sp_counted_base() noexcept
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{ }
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// Called when _M_use_count drops to zero, to release the resources
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// managed by *this.
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virtual void
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_M_dispose() noexcept = 0;
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// Called when _M_weak_count drops to zero.
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virtual void
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_M_destroy() noexcept
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{ delete this; }
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virtual void*
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_M_get_deleter(const std::type_info&) noexcept = 0;
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void
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_M_add_ref_copy()
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{ __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); }
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void
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_M_add_ref_lock();
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void
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_M_release() noexcept
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{
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// Be race-detector-friendly. For more info see bits/c++config.
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count);
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if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
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{
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
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_M_dispose();
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// There must be a memory barrier between dispose() and destroy()
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// to ensure that the effects of dispose() are observed in the
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// thread that runs destroy().
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// See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html
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if (_Mutex_base<_Lp>::_S_need_barriers)
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{
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_GLIBCXX_READ_MEM_BARRIER;
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_GLIBCXX_WRITE_MEM_BARRIER;
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}
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// Be race-detector-friendly. For more info see bits/c++config.
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
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if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count,
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-1) == 1)
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{
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
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_M_destroy();
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}
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}
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}
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void
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_M_weak_add_ref() noexcept
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{ __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); }
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void
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_M_weak_release() noexcept
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{
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// Be race-detector-friendly. For more info see bits/c++config.
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
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if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1)
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{
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
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if (_Mutex_base<_Lp>::_S_need_barriers)
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{
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// See _M_release(),
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// destroy() must observe results of dispose()
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_GLIBCXX_READ_MEM_BARRIER;
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_GLIBCXX_WRITE_MEM_BARRIER;
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}
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_M_destroy();
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}
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}
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long
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_M_get_use_count() const noexcept
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{
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// No memory barrier is used here so there is no synchronization
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// with other threads.
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return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED);
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}
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private:
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_Sp_counted_base(_Sp_counted_base const&) = delete;
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_Sp_counted_base& operator=(_Sp_counted_base const&) = delete;
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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 void
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_Sp_counted_base<_S_single>::
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_M_add_ref_lock()
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{
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if (_M_use_count == 0)
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__throw_bad_weak_ptr();
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++_M_use_count;
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}
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template<>
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inline void
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_Sp_counted_base<_S_mutex>::
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_M_add_ref_lock()
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{
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__gnu_cxx::__scoped_lock sentry(*this);
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if (__gnu_cxx::__exchange_and_add_dispatch(&_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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template<>
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inline void
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_Sp_counted_base<_S_atomic>::
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_M_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 = _M_use_count;
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do
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{
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if (__count == 0)
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__throw_bad_weak_ptr();
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// Replace the current counter value with the old value + 1, as
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// long as it's not changed meanwhile.
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}
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while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
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true, __ATOMIC_ACQ_REL,
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__ATOMIC_RELAXED));
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}
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template<>
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inline void
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_Sp_counted_base<_S_single>::_M_add_ref_copy()
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{ ++_M_use_count; }
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template<>
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inline void
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_Sp_counted_base<_S_single>::_M_release() noexcept
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{
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if (--_M_use_count == 0)
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{
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_M_dispose();
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if (--_M_weak_count == 0)
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_M_destroy();
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}
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}
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template<>
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inline void
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_Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept
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{ ++_M_weak_count; }
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template<>
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inline void
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_Sp_counted_base<_S_single>::_M_weak_release() noexcept
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{
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if (--_M_weak_count == 0)
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_M_destroy();
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}
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template<>
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inline long
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_Sp_counted_base<_S_single>::_M_get_use_count() const noexcept
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{ return _M_use_count; }
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// Forward declarations.
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template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
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class __shared_ptr;
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template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
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class __weak_ptr;
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template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
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class __enable_shared_from_this;
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template<typename _Tp>
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class shared_ptr;
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template<typename _Tp>
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class weak_ptr;
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template<typename _Tp>
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struct owner_less;
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template<typename _Tp>
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class enable_shared_from_this;
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template<_Lock_policy _Lp = __default_lock_policy>
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class __weak_count;
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template<_Lock_policy _Lp = __default_lock_policy>
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class __shared_count;
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// Counted ptr with no deleter or allocator support
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template<typename _Ptr, _Lock_policy _Lp>
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class _Sp_counted_ptr final : public _Sp_counted_base<_Lp>
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{
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public:
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explicit
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_Sp_counted_ptr(_Ptr __p) noexcept
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: _M_ptr(__p) { }
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virtual void
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_M_dispose() noexcept
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{ delete _M_ptr; }
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virtual void
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_M_destroy() noexcept
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{ delete this; }
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virtual void*
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_M_get_deleter(const std::type_info&) noexcept
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{ return nullptr; }
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_Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
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_Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
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private:
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_Ptr _M_ptr;
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};
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template<>
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inline void
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_Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { }
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template<>
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inline void
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_Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { }
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template<>
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inline void
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_Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { }
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template<int _Nm, typename _Tp,
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bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
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struct _Sp_ebo_helper;
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/// Specialization using EBO.
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template<int _Nm, typename _Tp>
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struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp
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{
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explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { }
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static _Tp&
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_S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); }
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};
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/// Specialization not using EBO.
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template<int _Nm, typename _Tp>
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struct _Sp_ebo_helper<_Nm, _Tp, false>
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{
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explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { }
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static _Tp&
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_S_get(_Sp_ebo_helper& __eboh)
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{ return __eboh._M_tp; }
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private:
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_Tp _M_tp;
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};
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// Support for custom deleter and/or allocator
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template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
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class _Sp_counted_deleter final : public _Sp_counted_base<_Lp>
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{
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class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc>
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{
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typedef _Sp_ebo_helper<0, _Deleter> _Del_base;
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typedef _Sp_ebo_helper<1, _Alloc> _Alloc_base;
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public:
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_Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
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: _M_ptr(__p), _Del_base(__d), _Alloc_base(__a)
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{ }
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_Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); }
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_Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); }
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_Ptr _M_ptr;
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};
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public:
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// __d(__p) must not throw.
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_Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept
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: _M_impl(__p, __d, _Alloc()) { }
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// __d(__p) must not throw.
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_Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
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: _M_impl(__p, __d, __a) { }
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~_Sp_counted_deleter() noexcept { }
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virtual void
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_M_dispose() noexcept
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{ _M_impl._M_del()(_M_impl._M_ptr); }
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virtual void
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_M_destroy() noexcept
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{
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typedef typename allocator_traits<_Alloc>::template
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rebind_traits<_Sp_counted_deleter> _Alloc_traits;
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typename _Alloc_traits::allocator_type __a(_M_impl._M_alloc());
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_Alloc_traits::destroy(__a, this);
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_Alloc_traits::deallocate(__a, this, 1);
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}
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virtual void*
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_M_get_deleter(const std::type_info& __ti) noexcept
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{
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#ifdef __GXX_RTTI
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return __ti == typeid(_Deleter) ? &_M_impl._M_del() : nullptr;
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#else
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return nullptr;
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#endif
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}
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private:
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_Impl _M_impl;
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};
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// helpers for make_shared / allocate_shared
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struct _Sp_make_shared_tag { };
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template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
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class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp>
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{
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class _Impl : _Sp_ebo_helper<0, _Alloc>
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{
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typedef _Sp_ebo_helper<0, _Alloc> _A_base;
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public:
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explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { }
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_Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); }
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__gnu_cxx::__aligned_buffer<_Tp> _M_storage;
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};
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public:
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template<typename... _Args>
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_Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
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: _M_impl(__a)
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{
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 2070. allocate_shared should use allocator_traits<A>::construct
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allocator_traits<_Alloc>::construct(__a, _M_ptr(),
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std::forward<_Args>(__args)...); // might throw
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}
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~_Sp_counted_ptr_inplace() noexcept { }
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virtual void
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_M_dispose() noexcept
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{
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allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr());
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}
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// Override because the allocator needs to know the dynamic type
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virtual void
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_M_destroy() noexcept
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{
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typedef typename allocator_traits<_Alloc>::template
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rebind_traits<_Sp_counted_ptr_inplace> _Alloc_traits;
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typename _Alloc_traits::allocator_type __a(_M_impl._M_alloc());
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_Alloc_traits::destroy(__a, this);
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_Alloc_traits::deallocate(__a, this, 1);
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}
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// Sneaky trick so __shared_ptr can get the managed pointer
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virtual void*
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_M_get_deleter(const std::type_info& __ti) noexcept
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{
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#ifdef __GXX_RTTI
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if (__ti == typeid(_Sp_make_shared_tag))
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return const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
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#endif
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return nullptr;
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}
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private:
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_Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); }
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_Impl _M_impl;
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};
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template<_Lock_policy _Lp>
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class __shared_count
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{
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public:
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constexpr __shared_count() noexcept : _M_pi(0)
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{ }
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template<typename _Ptr>
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explicit
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__shared_count(_Ptr __p) : _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_ptr<_Ptr, _Lp>(__p);
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}
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__catch(...)
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{
|
|
delete __p;
|
|
__throw_exception_again;
|
|
}
|
|
}
|
|
|
|
template<typename _Ptr, typename _Deleter>
|
|
__shared_count(_Ptr __p, _Deleter __d)
|
|
: __shared_count(__p, std::move(__d), allocator<void>())
|
|
{ }
|
|
|
|
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 allocator_traits<_Alloc>::template
|
|
rebind_traits<_Sp_cd_type> _Alloc_traits;
|
|
typename _Alloc_traits::allocator_type __a2(__a);
|
|
_Sp_cd_type* __mem = 0;
|
|
__try
|
|
{
|
|
__mem = _Alloc_traits::allocate(__a2, 1);
|
|
_Alloc_traits::construct(__a2, __mem,
|
|
__p, std::move(__d), std::move(__a));
|
|
_M_pi = __mem;
|
|
}
|
|
__catch(...)
|
|
{
|
|
__d(__p); // Call _Deleter on __p.
|
|
if (__mem)
|
|
_Alloc_traits::deallocate(__a2, __mem, 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 allocator_traits<_Alloc>::template
|
|
rebind_traits<_Sp_cp_type> _Alloc_traits;
|
|
typename _Alloc_traits::allocator_type __a2(__a);
|
|
_Sp_cp_type* __mem = _Alloc_traits::allocate(__a2, 1);
|
|
__try
|
|
{
|
|
_Alloc_traits::construct(__a2, __mem, std::move(__a),
|
|
std::forward<_Args>(__args)...);
|
|
_M_pi = __mem;
|
|
}
|
|
__catch(...)
|
|
{
|
|
_Alloc_traits::deallocate(__a2, __mem, 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);
|
|
#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(0)
|
|
{
|
|
using _Ptr = typename unique_ptr<_Tp, _Del>::pointer;
|
|
using _Del2 = typename conditional<is_reference<_Del>::value,
|
|
reference_wrapper<typename remove_reference<_Del>::type>,
|
|
_Del>::type;
|
|
using _Sp_cd_type
|
|
= _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>;
|
|
using _Alloc = allocator<_Sp_cd_type>;
|
|
using _Alloc_traits = allocator_traits<_Alloc>;
|
|
_Alloc __a;
|
|
_Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1);
|
|
_Alloc_traits::construct(__a, __mem, __r.release(),
|
|
__r.get_deleter()); // non-throwing
|
|
_M_pi = __mem;
|
|
}
|
|
|
|
// Throw bad_weak_ptr when __r._M_get_use_count() == 0.
|
|
explicit __shared_count(const __weak_count<_Lp>& __r);
|
|
|
|
~__shared_count() noexcept
|
|
{
|
|
if (_M_pi != nullptr)
|
|
_M_pi->_M_release();
|
|
}
|
|
|
|
__shared_count(const __shared_count& __r) noexcept
|
|
: _M_pi(__r._M_pi)
|
|
{
|
|
if (_M_pi != 0)
|
|
_M_pi->_M_add_ref_copy();
|
|
}
|
|
|
|
__shared_count&
|
|
operator=(const __shared_count& __r) noexcept
|
|
{
|
|
_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) noexcept
|
|
{
|
|
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
|
|
__r._M_pi = _M_pi;
|
|
_M_pi = __tmp;
|
|
}
|
|
|
|
long
|
|
_M_get_use_count() const noexcept
|
|
{ return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
|
|
|
|
bool
|
|
_M_unique() const noexcept
|
|
{ return this->_M_get_use_count() == 1; }
|
|
|
|
void*
|
|
_M_get_deleter(const std::type_info& __ti) const noexcept
|
|
{ return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; }
|
|
|
|
bool
|
|
_M_less(const __shared_count& __rhs) const noexcept
|
|
{ return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
|
|
|
|
bool
|
|
_M_less(const __weak_count<_Lp>& __rhs) const noexcept
|
|
{ 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) noexcept
|
|
{ return __a._M_pi == __b._M_pi; }
|
|
|
|
private:
|
|
friend class __weak_count<_Lp>;
|
|
|
|
_Sp_counted_base<_Lp>* _M_pi;
|
|
};
|
|
|
|
|
|
template<_Lock_policy _Lp>
|
|
class __weak_count
|
|
{
|
|
public:
|
|
constexpr __weak_count() noexcept : _M_pi(0)
|
|
{ }
|
|
|
|
__weak_count(const __shared_count<_Lp>& __r) noexcept
|
|
: _M_pi(__r._M_pi)
|
|
{
|
|
if (_M_pi != 0)
|
|
_M_pi->_M_weak_add_ref();
|
|
}
|
|
|
|
__weak_count(const __weak_count<_Lp>& __r) noexcept
|
|
: _M_pi(__r._M_pi)
|
|
{
|
|
if (_M_pi != 0)
|
|
_M_pi->_M_weak_add_ref();
|
|
}
|
|
|
|
~__weak_count() noexcept
|
|
{
|
|
if (_M_pi != 0)
|
|
_M_pi->_M_weak_release();
|
|
}
|
|
|
|
__weak_count<_Lp>&
|
|
operator=(const __shared_count<_Lp>& __r) noexcept
|
|
{
|
|
_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) noexcept
|
|
{
|
|
_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) noexcept
|
|
{
|
|
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
|
|
__r._M_pi = _M_pi;
|
|
_M_pi = __tmp;
|
|
}
|
|
|
|
long
|
|
_M_get_use_count() const noexcept
|
|
{ return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
|
|
|
|
bool
|
|
_M_less(const __weak_count& __rhs) const noexcept
|
|
{ return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
|
|
|
|
bool
|
|
_M_less(const __shared_count<_Lp>& __rhs) const noexcept
|
|
{ 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) noexcept
|
|
{ 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*) noexcept;
|
|
|
|
// 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*) noexcept;
|
|
|
|
template<_Lock_policy _Lp>
|
|
inline void
|
|
__enable_shared_from_this_helper(const __shared_count<_Lp>&, ...) noexcept
|
|
{ }
|
|
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
class __shared_ptr
|
|
{
|
|
public:
|
|
typedef _Tp element_type;
|
|
|
|
constexpr __shared_ptr() noexcept
|
|
: _M_ptr(0), _M_refcount()
|
|
{ }
|
|
|
|
template<typename _Tp1>
|
|
explicit __shared_ptr(_Tp1* __p)
|
|
: _M_ptr(__p), _M_refcount(__p)
|
|
{
|
|
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
|
|
static_assert( !is_void<_Tp>::value, "incomplete type" );
|
|
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) noexcept
|
|
: _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
|
|
{ }
|
|
|
|
__shared_ptr(const __shared_ptr&) noexcept = default;
|
|
__shared_ptr& operator=(const __shared_ptr&) noexcept = default;
|
|
~__shared_ptr() = default;
|
|
|
|
template<typename _Tp1, typename = typename
|
|
std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type>
|
|
__shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
|
|
: _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
|
|
{ }
|
|
|
|
__shared_ptr(__shared_ptr&& __r) noexcept
|
|
: _M_ptr(__r._M_ptr), _M_refcount()
|
|
{
|
|
_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) noexcept
|
|
: _M_ptr(__r._M_ptr), _M_refcount()
|
|
{
|
|
_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*>)
|
|
auto __raw = _S_raw_ptr(__r.get());
|
|
_M_refcount = __shared_count<_Lp>(std::move(__r));
|
|
__enable_shared_from_this_helper(_M_refcount, __raw, __raw);
|
|
}
|
|
|
|
#if _GLIBCXX_USE_DEPRECATED
|
|
// Postcondition: use_count() == 1 and __r.get() == 0
|
|
template<typename _Tp1>
|
|
__shared_ptr(std::auto_ptr<_Tp1>&& __r);
|
|
#endif
|
|
|
|
/* TODO: use delegating constructor */
|
|
constexpr __shared_ptr(nullptr_t) noexcept
|
|
: _M_ptr(0), _M_refcount()
|
|
{ }
|
|
|
|
template<typename _Tp1>
|
|
__shared_ptr&
|
|
operator=(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
|
|
{
|
|
_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) noexcept
|
|
{
|
|
__shared_ptr(std::move(__r)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
template<class _Tp1>
|
|
__shared_ptr&
|
|
operator=(__shared_ptr<_Tp1, _Lp>&& __r) noexcept
|
|
{
|
|
__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() noexcept
|
|
{ __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 noexcept
|
|
{
|
|
_GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
|
|
return *_M_ptr;
|
|
}
|
|
|
|
_Tp*
|
|
operator->() const noexcept
|
|
{
|
|
_GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
|
|
return _M_ptr;
|
|
}
|
|
|
|
_Tp*
|
|
get() const noexcept
|
|
{ return _M_ptr; }
|
|
|
|
explicit operator bool() const // never throws
|
|
{ return _M_ptr == 0 ? false : true; }
|
|
|
|
bool
|
|
unique() const noexcept
|
|
{ return _M_refcount._M_unique(); }
|
|
|
|
long
|
|
use_count() const noexcept
|
|
{ return _M_refcount._M_get_use_count(); }
|
|
|
|
void
|
|
swap(__shared_ptr<_Tp, _Lp>& __other) noexcept
|
|
{
|
|
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)
|
|
{
|
|
typedef allocator_traits<_Alloc> _Alloc_traits;
|
|
_Alloc_traits::destroy(_M_alloc, __ptr);
|
|
_Alloc_traits::deallocate(_M_alloc, __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) };
|
|
typedef allocator_traits<_Alloc2> __traits;
|
|
_M_ptr = __traits::allocate(__del._M_alloc, 1);
|
|
__try
|
|
{
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2070. allocate_shared should use allocator_traits<A>::construct
|
|
__traits::construct(__del._M_alloc, _M_ptr,
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
__catch(...)
|
|
{
|
|
__traits::deallocate(__del._M_alloc, _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 noexcept
|
|
{ return _M_refcount._M_get_deleter(__ti); }
|
|
|
|
template<typename _Tp1>
|
|
static _Tp1*
|
|
_S_raw_ptr(_Tp1* __ptr)
|
|
{ return __ptr; }
|
|
|
|
template<typename _Tp1>
|
|
static auto
|
|
_S_raw_ptr(_Tp1 __ptr) -> decltype(std::__addressof(*__ptr))
|
|
{ return std::__addressof(*__ptr); }
|
|
|
|
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>&) noexcept;
|
|
|
|
_Tp* _M_ptr; // Contained pointer.
|
|
__shared_count<_Lp> _M_refcount; // Reference counter.
|
|
};
|
|
|
|
|
|
// 20.7.2.2.7 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) noexcept
|
|
{ return __a.get() == __b.get(); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
|
|
{ return !__a; }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
|
|
{ return !__a; }
|
|
|
|
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
|
|
inline bool
|
|
operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
|
|
const __shared_ptr<_Tp2, _Lp>& __b) noexcept
|
|
{ return __a.get() != __b.get(); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
|
|
{ return (bool)__a; }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
|
|
{ return (bool)__a; }
|
|
|
|
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
|
|
inline bool
|
|
operator<(const __shared_ptr<_Tp1, _Lp>& __a,
|
|
const __shared_ptr<_Tp2, _Lp>& __b) noexcept
|
|
{
|
|
typedef typename std::common_type<_Tp1*, _Tp2*>::type _CT;
|
|
return std::less<_CT>()(__a.get(), __b.get());
|
|
}
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
|
|
{ return std::less<_Tp*>()(__a.get(), nullptr); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
|
|
{ return std::less<_Tp*>()(nullptr, __a.get()); }
|
|
|
|
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
|
|
inline bool
|
|
operator<=(const __shared_ptr<_Tp1, _Lp>& __a,
|
|
const __shared_ptr<_Tp2, _Lp>& __b) noexcept
|
|
{ return !(__b < __a); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
|
|
{ return !(nullptr < __a); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
|
|
{ return !(__a < nullptr); }
|
|
|
|
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
|
|
inline bool
|
|
operator>(const __shared_ptr<_Tp1, _Lp>& __a,
|
|
const __shared_ptr<_Tp2, _Lp>& __b) noexcept
|
|
{ return (__b < __a); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
|
|
{ return std::less<_Tp*>()(nullptr, __a.get()); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
|
|
{ return std::less<_Tp*>()(__a.get(), nullptr); }
|
|
|
|
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
|
|
inline bool
|
|
operator>=(const __shared_ptr<_Tp1, _Lp>& __a,
|
|
const __shared_ptr<_Tp2, _Lp>& __b) noexcept
|
|
{ return !(__a < __b); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
|
|
{ return !(__a < nullptr); }
|
|
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline bool
|
|
operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
|
|
{ return !(nullptr < __a); }
|
|
|
|
template<typename _Sp>
|
|
struct _Sp_less : public binary_function<_Sp, _Sp, bool>
|
|
{
|
|
bool
|
|
operator()(const _Sp& __lhs, const _Sp& __rhs) const noexcept
|
|
{
|
|
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>>
|
|
{ };
|
|
|
|
// 20.7.2.2.8 shared_ptr specialized algorithms.
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline void
|
|
swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept
|
|
{ __a.swap(__b); }
|
|
|
|
// 20.7.2.2.9 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) noexcept
|
|
{ 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) noexcept
|
|
{ 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) noexcept
|
|
{
|
|
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() noexcept
|
|
: _M_ptr(0), _M_refcount()
|
|
{ }
|
|
|
|
__weak_ptr(const __weak_ptr&) noexcept = default;
|
|
__weak_ptr& operator=(const __weak_ptr&) noexcept = default;
|
|
~__weak_ptr() = default;
|
|
|
|
// 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) noexcept
|
|
: _M_refcount(__r._M_refcount)
|
|
{ _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) noexcept
|
|
: _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
|
|
{ }
|
|
|
|
template<typename _Tp1>
|
|
__weak_ptr&
|
|
operator=(const __weak_ptr<_Tp1, _Lp>& __r) noexcept
|
|
{
|
|
_M_ptr = __r.lock().get();
|
|
_M_refcount = __r._M_refcount;
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Tp1>
|
|
__weak_ptr&
|
|
operator=(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
|
|
{
|
|
_M_ptr = __r._M_ptr;
|
|
_M_refcount = __r._M_refcount;
|
|
return *this;
|
|
}
|
|
|
|
__shared_ptr<_Tp, _Lp>
|
|
lock() const noexcept
|
|
{
|
|
#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 noexcept
|
|
{ return _M_refcount._M_get_use_count(); }
|
|
|
|
bool
|
|
expired() const noexcept
|
|
{ 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() noexcept
|
|
{ __weak_ptr().swap(*this); }
|
|
|
|
void
|
|
swap(__weak_ptr& __s) noexcept
|
|
{
|
|
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) noexcept
|
|
{
|
|
_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.
|
|
};
|
|
|
|
// 20.7.2.3.6 weak_ptr specialized algorithms.
|
|
template<typename _Tp, _Lock_policy _Lp>
|
|
inline void
|
|
swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept
|
|
{ __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() noexcept { }
|
|
|
|
__enable_shared_from_this(const __enable_shared_from_this&) noexcept { }
|
|
|
|
__enable_shared_from_this&
|
|
operator=(const __enable_shared_from_this&) noexcept
|
|
{ return *this; }
|
|
|
|
~__enable_shared_from_this() { }
|
|
|
|
public:
|
|
__shared_ptr<_Tp, _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 noexcept
|
|
{ _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) noexcept
|
|
{
|
|
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.
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|
template<typename _Tp, _Lock_policy _Lp>
|
|
struct hash<__shared_ptr<_Tp, _Lp>>
|
|
: public __hash_base<size_t, __shared_ptr<_Tp, _Lp>>
|
|
{
|
|
size_t
|
|
operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept
|
|
{ return std::hash<_Tp*>()(__s.get()); }
|
|
};
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|
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_GLIBCXX_END_NAMESPACE_VERSION
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|
} // namespace
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|
|
|
#endif // _SHARED_PTR_BASE_H
|