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gcc/libstdc++-v3/include/bits/shared_ptr.h
Jonathan Wakely 2ea259393d shared_ptr.h: Do not swap rvalues. 
2009-06-23  Jonathan Wakely  <jwakely.gcc@gmail.com>

	* include/bits/shared_ptr.h: Do not swap rvalues.
	* testsuite/20_util/owner_less/cmp.cc: Add missing test variables.
	* testsuite/20_util/shared_ptr/comparison/cmp.cc: Likewise.
	* testsuite/20_util/shared_ptr/comparison/less.cc: Likewise.
	* testsuite/20_util/weak_ptr/observers/owner_before.cc: Likewise.
	* testsuite/20_util/tuple/swap.cc: Likewise.

From-SVN: r148880
2009-06-23 23:33:17 +01:00

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// shared_ptr and weak_ptr implementation -*- C++ -*-
// Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
// shared_count.hpp
// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
// shared_ptr.hpp
// Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
// Copyright (C) 2001, 2002, 2003 Peter Dimov
// weak_ptr.hpp
// Copyright (C) 2001, 2002, 2003 Peter Dimov
// enable_shared_from_this.hpp
// Copyright (C) 2002 Peter Dimov
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// GCC Note: based on version 1.32.0 of the Boost library.
/** @file bits/shared_ptr.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*/
#ifndef _SHARED_PTR_H
#define _SHARED_PTR_H 1
#ifndef __GXX_EXPERIMENTAL_CXX0X__
# include <c++0x_warning.h>
#endif
#if defined(_GLIBCXX_INCLUDE_AS_TR1)
# error C++0x header cannot be included from TR1 header
#endif
_GLIBCXX_BEGIN_NAMESPACE(std)
/**
* @addtogroup pointer_abstractions
* @{
*/
// counted ptr with no deleter or allocator support
template<typename _Ptr, _Lock_policy _Lp>
class _Sp_counted_ptr
: public _Sp_counted_base<_Lp>
{
public:
_Sp_counted_ptr(_Ptr __p)
: _M_ptr(__p) { }
virtual void
_M_dispose() // nothrow
{ delete _M_ptr; }
virtual void
_M_destroy() // nothrow
{ delete this; }
virtual void*
_M_get_deleter(const std::type_info& __ti)
{ return 0; }
_Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
_Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
protected:
_Ptr _M_ptr; // copy constructor must not throw
};
// support for custom deleter and/or allocator
template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
class _Sp_counted_deleter
: public _Sp_counted_ptr<_Ptr, _Lp>
{
typedef typename _Alloc::template
rebind<_Sp_counted_deleter>::other _My_alloc_type;
// Helper class that stores the Deleter and also acts as an allocator.
// Used to dispose of the owned pointer and the internal refcount
// Requires that copies of _Alloc can free each other's memory.
struct _My_Deleter
: public _My_alloc_type // copy constructor must not throw
{
_Deleter _M_del; // copy constructor must not throw
_My_Deleter(_Deleter __d, const _Alloc& __a)
: _My_alloc_type(__a), _M_del(__d) { }
};
protected:
typedef _Sp_counted_ptr<_Ptr, _Lp> _Base_type;
public:
/**
* @brief
* @pre __d(__p) must not throw.
*/
_Sp_counted_deleter(_Ptr __p, _Deleter __d)
: _Base_type(__p), _M_del(__d, _Alloc()) { }
/**
* @brief
* @pre __d(__p) must not throw.
*/
_Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a)
: _Base_type(__p), _M_del(__d, __a) { }
virtual void
_M_dispose() // nothrow
{ _M_del._M_del(_Base_type::_M_ptr); }
virtual void
_M_destroy() // nothrow
{
_My_alloc_type __a(_M_del);
this->~_Sp_counted_deleter();
__a.deallocate(this, 1);
}
virtual void*
_M_get_deleter(const std::type_info& __ti)
{ return __ti == typeid(_Deleter) ? &_M_del._M_del : 0; }
protected:
_My_Deleter _M_del; // copy constructor must not throw
};
// helpers for make_shared / allocate_shared
template<typename _Tp>
struct _Sp_destroy_inplace
{
void operator()(_Tp* __p) const { if (__p) __p->~_Tp(); }
};
struct _Sp_make_shared_tag { };
template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
class _Sp_counted_ptr_inplace
: public _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp>
{
typedef _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp>
_Base_type;
public:
_Sp_counted_ptr_inplace(_Alloc __a)
: _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a)
, _M_storage()
{
void* __p = &_M_storage;
::new (__p) _Tp(); // might throw
_Base_type::_Base_type::_M_ptr = static_cast<_Tp*>(__p);
}
template<typename... _Args>
_Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
: _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a)
, _M_storage()
{
void* __p = &_M_storage;
::new (__p) _Tp(std::forward<_Args>(__args)...); // might throw
_Base_type::_Base_type::_M_ptr = static_cast<_Tp*>(__p);
}
// override because the allocator needs to know the dynamic type
virtual void
_M_destroy() // nothrow
{
typedef typename _Alloc::template
rebind<_Sp_counted_ptr_inplace>::other _My_alloc_type;
_My_alloc_type __a(_Base_type::_M_del);
this->~_Sp_counted_ptr_inplace();
__a.deallocate(this, 1);
}
// sneaky trick so __shared_ptr can get the managed pointer
virtual void*
_M_get_deleter(const std::type_info& __ti)
{
return __ti == typeid(_Sp_make_shared_tag)
? static_cast<void*>(&_M_storage)
: _Base_type::_M_get_deleter(__ti);
}
private:
typename aligned_storage<sizeof(_Tp), alignment_of<_Tp>::value>::type
_M_storage;
};
template<_Lock_policy _Lp = __default_lock_policy>
class __weak_count;
template<_Lock_policy _Lp = __default_lock_policy>
class __shared_count
{
public:
__shared_count()
: _M_pi(0) // nothrow
{ }
template<typename _Ptr>
__shared_count(_Ptr __p) : _M_pi(0)
{
__try
{
_M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
}
__catch(...)
{
delete __p;
__throw_exception_again;
}
}
template<typename _Ptr, typename _Deleter>
__shared_count(_Ptr __p, _Deleter __d) : _M_pi(0)
{
// allocator's value_type doesn't matter, will rebind it anyway
typedef std::allocator<int> _Alloc;
typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
typedef std::allocator<_Sp_cd_type> _Alloc2;
_Alloc2 __a2;
__try
{
_M_pi = __a2.allocate(1);
::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d);
}
__catch(...)
{
__d(__p); // Call _Deleter on __p.
if (_M_pi)
__a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1);
__throw_exception_again;
}
}
template<typename _Ptr, typename _Deleter, typename _Alloc>
__shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
{
typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
typedef typename _Alloc::template rebind<_Sp_cd_type>::other _Alloc2;
_Alloc2 __a2(__a);
__try
{
_M_pi = __a2.allocate(1);
::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d, __a);
}
__catch(...)
{
__d(__p); // Call _Deleter on __p.
if (_M_pi)
__a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1);
__throw_exception_again;
}
}
template<typename _Tp, typename _Alloc, typename... _Args>
__shared_count(_Sp_make_shared_tag, _Tp*, _Alloc __a, _Args&&... __args)
: _M_pi(0)
{
typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
typedef typename _Alloc::template rebind<_Sp_cp_type>::other _Alloc2;
_Alloc2 __a2(__a);
__try
{
_M_pi = __a2.allocate(1);
::new(static_cast<void*>(_M_pi)) _Sp_cp_type(__a,
std::forward<_Args>(__args)...);
}
__catch(...)
{
if (_M_pi)
__a2.deallocate(static_cast<_Sp_cp_type*>(_M_pi), 1);
__throw_exception_again;
}
}
#if _GLIBCXX_DEPRECATED
// Special case for auto_ptr<_Tp> to provide the strong guarantee.
template<typename _Tp>
explicit
__shared_count(std::auto_ptr<_Tp>&& __r)
: _M_pi(new _Sp_counted_ptr<_Tp*, _Lp>(__r.get()))
{ __r.release(); }
#endif
// Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
template<typename _Tp, typename _Del>
explicit
__shared_count(std::unique_ptr<_Tp, _Del>&& __r)
: _M_pi(_S_create_from_up(std::move(__r)))
{ __r.release(); }
// Throw bad_weak_ptr when __r._M_get_use_count() == 0.
explicit
__shared_count(const __weak_count<_Lp>& __r);
~__shared_count() // nothrow
{
if (_M_pi != 0)
_M_pi->_M_release();
}
__shared_count(const __shared_count& __r)
: _M_pi(__r._M_pi) // nothrow
{
if (_M_pi != 0)
_M_pi->_M_add_ref_copy();
}
__shared_count&
operator=(const __shared_count& __r) // nothrow
{
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
if (__tmp != _M_pi)
{
if (__tmp != 0)
__tmp->_M_add_ref_copy();
if (_M_pi != 0)
_M_pi->_M_release();
_M_pi = __tmp;
}
return *this;
}
void
_M_swap(__shared_count& __r) // nothrow
{
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
__r._M_pi = _M_pi;
_M_pi = __tmp;
}
long
_M_get_use_count() const // nothrow
{ return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
bool
_M_unique() const // nothrow
{ return this->_M_get_use_count() == 1; }
void*
_M_get_deleter(const std::type_info& __ti) const
{ return _M_pi ? _M_pi->_M_get_deleter(__ti) : 0; }
bool
_M_less(const __shared_count& __rhs) const
{ return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
bool
_M_less(const __weak_count<_Lp>& __rhs) const
{ return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
// friend function injected into enclosing namespace and found by ADL
friend inline bool
operator==(const __shared_count& __a, const __shared_count& __b)
{ return __a._M_pi == __b._M_pi; }
private:
friend class __weak_count<_Lp>;
template<typename _Tp, typename _Del>
static _Sp_counted_base<_Lp>*
_S_create_from_up(std::unique_ptr<_Tp, _Del>&& __r,
typename std::enable_if<!std::is_reference<_Del>::value>::type* = 0)
{
return new _Sp_counted_deleter<_Tp*, _Del, std::allocator<_Tp>,
_Lp>(__r.get(), __r.get_deleter());
}
template<typename _Tp, typename _Del>
static _Sp_counted_base<_Lp>*
_S_create_from_up(std::unique_ptr<_Tp, _Del>&& __r,
typename std::enable_if<std::is_reference<_Del>::value>::type* = 0)
{
typedef typename std::remove_reference<_Del>::type _Del1;
typedef std::reference_wrapper<_Del1> _Del2;
return new _Sp_counted_deleter<_Tp*, _Del2, std::allocator<_Tp>,
_Lp>(__r.get(), std::ref(__r.get_deleter()));
}
_Sp_counted_base<_Lp>* _M_pi;
};
template<_Lock_policy _Lp>
class __weak_count
{
public:
__weak_count()
: _M_pi(0) // nothrow
{ }
__weak_count(const __shared_count<_Lp>& __r)
: _M_pi(__r._M_pi) // nothrow
{
if (_M_pi != 0)
_M_pi->_M_weak_add_ref();
}
__weak_count(const __weak_count<_Lp>& __r)
: _M_pi(__r._M_pi) // nothrow
{
if (_M_pi != 0)
_M_pi->_M_weak_add_ref();
}
~__weak_count() // nothrow
{
if (_M_pi != 0)
_M_pi->_M_weak_release();
}
__weak_count<_Lp>&
operator=(const __shared_count<_Lp>& __r) // nothrow
{
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
if (__tmp != 0)
__tmp->_M_weak_add_ref();
if (_M_pi != 0)
_M_pi->_M_weak_release();
_M_pi = __tmp;
return *this;
}
__weak_count<_Lp>&
operator=(const __weak_count<_Lp>& __r) // nothrow
{
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
if (__tmp != 0)
__tmp->_M_weak_add_ref();
if (_M_pi != 0)
_M_pi->_M_weak_release();
_M_pi = __tmp;
return *this;
}
void
_M_swap(__weak_count<_Lp>& __r) // nothrow
{
_Sp_counted_base<_Lp>* __tmp = __r._M_pi;
__r._M_pi = _M_pi;
_M_pi = __tmp;
}
long
_M_get_use_count() const // nothrow
{ return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
bool
_M_less(const __weak_count& __rhs) const
{ return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
bool
_M_less(const __shared_count<_Lp>& __rhs) const
{ return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
// friend function injected into enclosing namespace and found by ADL
friend inline bool
operator==(const __weak_count& __a, const __weak_count& __b)
{ return __a._M_pi == __b._M_pi; }
private:
friend class __shared_count<_Lp>;
_Sp_counted_base<_Lp>* _M_pi;
};
// now that __weak_count is defined we can define this constructor:
template<_Lock_policy _Lp>
inline
__shared_count<_Lp>::
__shared_count(const __weak_count<_Lp>& __r)
: _M_pi(__r._M_pi)
{
if (_M_pi != 0)
_M_pi->_M_add_ref_lock();
else
__throw_bad_weak_ptr();
}
// Forward declarations.
template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
class __shared_ptr;
template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
class __weak_ptr;
template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
class __enable_shared_from_this;
template<typename _Tp>
class shared_ptr;
template<typename _Tp>
class weak_ptr;
template<typename _Tp>
class enable_shared_from_this;
// Support for enable_shared_from_this.
// Friend of __enable_shared_from_this.
template<_Lock_policy _Lp, typename _Tp1, typename _Tp2>
void
__enable_shared_from_this_helper(const __shared_count<_Lp>&,
const __enable_shared_from_this<_Tp1,
_Lp>*, const _Tp2*);
// Friend of enable_shared_from_this.
template<typename _Tp1, typename _Tp2>
void
__enable_shared_from_this_helper(const __shared_count<>&,
const enable_shared_from_this<_Tp1>*,
const _Tp2*);
template<_Lock_policy _Lp>
inline void
__enable_shared_from_this_helper(const __shared_count<_Lp>&, ...)
{ }
template<typename _Tp, _Lock_policy _Lp>
class __shared_ptr
{
public:
typedef _Tp element_type;
/** @brief Construct an empty %__shared_ptr.
* @post use_count()==0 && get()==0
*/
__shared_ptr()
: _M_ptr(0), _M_refcount() // never throws
{ }
/** @brief Construct a %__shared_ptr that owns the pointer @a __p.
* @param __p A pointer that is convertible to element_type*.
* @post use_count() == 1 && get() == __p
* @throw std::bad_alloc, in which case @c delete @a __p is called.
*/
template<typename _Tp1>
explicit
__shared_ptr(_Tp1* __p)
: _M_ptr(__p), _M_refcount(__p)
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
// __glibcxx_function_requires(_CompleteConcept<_Tp1*>)
__enable_shared_from_this_helper(_M_refcount, __p, __p);
}
//
// Requirements: _Deleter's copy constructor and destructor must
// not throw
//
// __shared_ptr will release __p by calling __d(__p)
//
/** @brief Construct a %__shared_ptr that owns the pointer @a __p
* and the deleter @a __d.
* @param __p A pointer.
* @param __d A deleter.
* @post use_count() == 1 && get() == __p
* @throw std::bad_alloc, in which case @a __d(__p) is called.
*/
template<typename _Tp1, typename _Deleter>
__shared_ptr(_Tp1* __p, _Deleter __d)
: _M_ptr(__p), _M_refcount(__p, __d)
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
// TODO requires _Deleter CopyConstructible and __d(__p) well-formed
__enable_shared_from_this_helper(_M_refcount, __p, __p);
}
//
// Requirements: _Deleter's copy constructor and destructor must
// not throw _Alloc's copy constructor and destructor must not
// throw.
//
// __shared_ptr will release __p by calling __d(__p)
//
/** @brief Construct a %__shared_ptr that owns the pointer @a __p
* and the deleter @a __d.
* @param __p A pointer.
* @param __d A deleter.
* @param __a An allocator.
* @post use_count() == 1 && get() == __p
* @throw std::bad_alloc, in which case @a __d(__p) is called.
*/
template<typename _Tp1, typename _Deleter, typename _Alloc>
__shared_ptr(_Tp1* __p, _Deleter __d, const _Alloc& __a)
: _M_ptr(__p), _M_refcount(__p, __d, __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);
}
/** @brief Constructs a %__shared_ptr instance that stores @a __p
* and shares ownership with @a __r.
* @param __r A %__shared_ptr.
* @param __p A pointer that will remain valid while @a *__r is valid.
* @post get() == __p && use_count() == __r.use_count()
*
* This can be used to construct a @c shared_ptr to a sub-object
* of an object managed by an existing @c shared_ptr.
*
* @code
* shared_ptr< pair<int,int> > pii(new pair<int,int>());
* shared_ptr<int> pi(pii, &pii->first);
* assert(pii.use_count() == 2);
* @endcode
*/
template<typename _Tp1>
__shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, _Tp* __p)
: _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
{ }
// generated copy constructor, assignment, destructor are fine.
/** @brief If @a __r is empty, constructs an empty %__shared_ptr;
* otherwise construct a %__shared_ptr that shares ownership
* with @a __r.
* @param __r A %__shared_ptr.
* @post get() == __r.get() && use_count() == __r.use_count()
*/
template<typename _Tp1>
__shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r)
: _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
{ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) }
/** @brief Move-constructs a %__shared_ptr instance from @a __r.
* @param __r A %__shared_ptr rvalue.
* @post *this contains the old value of @a __r, @a __r is empty.
*/
__shared_ptr(__shared_ptr&& __r)
: _M_ptr(__r._M_ptr), _M_refcount() // never throws
{
_M_refcount._M_swap(__r._M_refcount);
__r._M_ptr = 0;
}
/** @brief Move-constructs a %__shared_ptr instance from @a __r.
* @param __r A %__shared_ptr rvalue.
* @post *this contains the old value of @a __r, @a __r is empty.
*/
template<typename _Tp1>
__shared_ptr(__shared_ptr<_Tp1, _Lp>&& __r)
: _M_ptr(__r._M_ptr), _M_refcount() // never throws
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
_M_refcount._M_swap(__r._M_refcount);
__r._M_ptr = 0;
}
/** @brief Constructs a %__shared_ptr that shares ownership with @a __r
* and stores a copy of the pointer stored in @a __r.
* @param __r A weak_ptr.
* @post use_count() == __r.use_count()
* @throw bad_weak_ptr when __r.expired(),
* in which case the constructor has no effect.
*/
template<typename _Tp1>
explicit
__shared_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
: _M_refcount(__r._M_refcount) // may throw
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
// It is now safe to copy __r._M_ptr, as _M_refcount(__r._M_refcount)
// did not throw.
_M_ptr = __r._M_ptr;
}
template<typename _Tp1, typename _Del>
explicit
__shared_ptr(const std::unique_ptr<_Tp1, _Del>&) = delete;
/**
* If an exception is thrown this constructor has no effect.
*/
template<typename _Tp1, typename _Del>
explicit
__shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
: _M_ptr(__r.get()), _M_refcount()
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
_Tp1* __tmp = __r.get();
_M_refcount = __shared_count<_Lp>(std::move(__r));
__enable_shared_from_this_helper(_M_refcount, __tmp, __tmp);
}
#if _GLIBCXX_DEPRECATED
/**
* @post use_count() == 1 and __r.get() == 0
*/
template<typename _Tp1>
explicit
__shared_ptr(std::auto_ptr<_Tp1>&& __r)
: _M_ptr(__r.get()), _M_refcount()
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
// TODO requires _Tp1 is complete, delete __r.release() well-formed
_Tp1* __tmp = __r.get();
_M_refcount = __shared_count<_Lp>(std::move(__r));
__enable_shared_from_this_helper(_M_refcount, __tmp, __tmp);
}
#endif
template<typename _Tp1>
__shared_ptr&
operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws
{
_M_ptr = __r._M_ptr;
_M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
return *this;
}
#if _GLIBCXX_DEPRECATED
template<typename _Tp1>
__shared_ptr&
operator=(std::auto_ptr<_Tp1>&& __r)
{
__shared_ptr(std::move(__r)).swap(*this);
return *this;
}
#endif
__shared_ptr&
operator=(__shared_ptr&& __r)
{
__shared_ptr(std::move(__r)).swap(*this);
return *this;
}
template<class _Tp1>
__shared_ptr&
operator=(__shared_ptr<_Tp1, _Lp>&& __r)
{
__shared_ptr(std::move(__r)).swap(*this);
return *this;
}
template<typename _Tp1, typename _Del>
__shared_ptr&
operator=(const std::unique_ptr<_Tp1, _Del>& __r) = delete;
template<typename _Tp1, typename _Del>
__shared_ptr&
operator=(std::unique_ptr<_Tp1, _Del>&& __r)
{
__shared_ptr(std::move(__r)).swap(*this);
return *this;
}
void
reset() // never throws
{ __shared_ptr().swap(*this); }
template<typename _Tp1>
void
reset(_Tp1* __p) // _Tp1 must be complete.
{
// Catch self-reset errors.
_GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr);
__shared_ptr(__p).swap(*this);
}
template<typename _Tp1, typename _Deleter>
void
reset(_Tp1* __p, _Deleter __d)
{ __shared_ptr(__p, __d).swap(*this); }
template<typename _Tp1, typename _Deleter, typename _Alloc>
void
reset(_Tp1* __p, _Deleter __d, const _Alloc& __a)
{ __shared_ptr(__p, __d, __a).swap(*this); }
// Allow class instantiation when _Tp is [cv-qual] void.
typename std::add_lvalue_reference<_Tp>::type
operator*() const // never throws
{
_GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
return *_M_ptr;
}
_Tp*
operator->() const // never throws
{
_GLIBCXX_DEBUG_ASSERT(_M_ptr != 0);
return _M_ptr;
}
_Tp*
get() const // never throws
{ return _M_ptr; }
explicit operator bool() const // never throws
{ return _M_ptr == 0 ? false : true; }
bool
unique() const // never throws
{ return _M_refcount._M_unique(); }
long
use_count() const // never throws
{ return _M_refcount._M_get_use_count(); }
void
swap(__shared_ptr<_Tp, _Lp>& __other) // never throws
{
std::swap(_M_ptr, __other._M_ptr);
_M_refcount._M_swap(__other._M_refcount);
}
template<typename _Tp1>
bool
owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const
{ return _M_refcount._M_less(__rhs._M_refcount); }
template<typename _Tp1>
bool
owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const
{ return _M_refcount._M_less(__rhs._M_refcount); }
protected:
// This constructor is non-standard, it is used by allocate_shared.
template<typename _Alloc, typename... _Args>
__shared_ptr(_Sp_make_shared_tag __tag, _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);
}
template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
typename... _Args>
friend __shared_ptr<_Tp1, _Lp1>
__allocate_shared(_Alloc __a, _Args&&... __args);
private:
void*
_M_get_deleter(const std::type_info& __ti) const
{ return _M_refcount._M_get_deleter(__ti); }
template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&);
_Tp* _M_ptr; // Contained pointer.
__shared_count<_Lp> _M_refcount; // Reference counter.
};
// 20.8.13.2.7 shared_ptr comparisons
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
inline bool
operator==(const __shared_ptr<_Tp1, _Lp>& __a,
const __shared_ptr<_Tp2, _Lp>& __b)
{ return __a.get() == __b.get(); }
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
inline bool
operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
const __shared_ptr<_Tp2, _Lp>& __b)
{ return __a.get() != __b.get(); }
template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
inline bool
operator<(const __shared_ptr<_Tp1, _Lp>& __a,
const __shared_ptr<_Tp2, _Lp>& __b)
{ return __a.get() < __b.get(); }
template<typename _Sp>
struct _Sp_less : public binary_function<_Sp, _Sp, bool>
{
bool
operator()(const _Sp& __lhs, const _Sp& __rhs) const
{
return std::less<typename _Sp::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>>
{ };
// XXX LessThanComparable<_Tp> concept should provide >, >= and <=
template<typename _Tp, _Lock_policy _Lp>
inline bool
operator>(const __shared_ptr<_Tp, _Lp>& __a,
const __shared_ptr<_Tp, _Lp>& __b)
{ return __a.get() > __b.get(); }
template<typename _Tp, _Lock_policy _Lp>
inline bool
operator>=(const __shared_ptr<_Tp, _Lp>& __a,
const __shared_ptr<_Tp, _Lp>& __b)
{ return __a.get() >= __b.get(); }
template<typename _Tp, _Lock_policy _Lp>
inline bool
operator<=(const __shared_ptr<_Tp, _Lp>& __a,
const __shared_ptr<_Tp, _Lp>& __b)
{ return __a.get() <= __b.get(); }
// 2.2.3.8 shared_ptr specialized algorithms.
template<typename _Tp, _Lock_policy _Lp>
inline void
swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b)
{ __a.swap(__b); }
// 2.2.3.9 shared_ptr casts
/** @warning The seemingly equivalent
* <code>shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))</code>
* will eventually result in undefined behaviour,
* attempting to delete the same object twice.
*/
template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
inline __shared_ptr<_Tp, _Lp>
static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
{ return __shared_ptr<_Tp, _Lp>(__r, static_cast<_Tp*>(__r.get())); }
/** @warning The seemingly equivalent
* <code>shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))</code>
* will eventually result in undefined behaviour,
* attempting to delete the same object twice.
*/
template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
inline __shared_ptr<_Tp, _Lp>
const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
{ return __shared_ptr<_Tp, _Lp>(__r, const_cast<_Tp*>(__r.get())); }
/** @warning The seemingly equivalent
* <code>shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))</code>
* will eventually result in undefined behaviour,
* attempting to delete the same object twice.
*/
template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
inline __shared_ptr<_Tp, _Lp>
dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r)
{
if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
return __shared_ptr<_Tp, _Lp>(__r, __p);
return __shared_ptr<_Tp, _Lp>();
}
// 2.2.3.7 shared_ptr I/O
template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp>
std::basic_ostream<_Ch, _Tr>&
operator<<(std::basic_ostream<_Ch, _Tr>& __os,
const __shared_ptr<_Tp, _Lp>& __p)
{
__os << __p.get();
return __os;
}
// 2.2.3.10 shared_ptr get_deleter (experimental)
template<typename _Del, typename _Tp, _Lock_policy _Lp>
inline _Del*
get_deleter(const __shared_ptr<_Tp, _Lp>& __p)
{ return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); }
template<typename _Tp, _Lock_policy _Lp>
class __weak_ptr
{
public:
typedef _Tp element_type;
__weak_ptr()
: _M_ptr(0), _M_refcount() // never throws
{ }
// Generated copy constructor, assignment, destructor are fine.
// The "obvious" converting constructor implementation:
//
// template<typename _Tp1>
// __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
// : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
// { }
//
// has a serious problem.
//
// __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
// conversion may require access to *__r._M_ptr (virtual inheritance).
//
// It is not possible to avoid spurious access violations since
// in multithreaded programs __r._M_ptr may be invalidated at any point.
template<typename _Tp1>
__weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
: _M_refcount(__r._M_refcount) // never throws
{
__glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
_M_ptr = __r.lock().get();
}
template<typename _Tp1>
__weak_ptr(const __shared_ptr<_Tp1, _Lp>& __r)
: _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
{ __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) }
template<typename _Tp1>
__weak_ptr&
operator=(const __weak_ptr<_Tp1, _Lp>& __r) // never throws
{
_M_ptr = __r.lock().get();
_M_refcount = __r._M_refcount;
return *this;
}
template<typename _Tp1>
__weak_ptr&
operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws
{
_M_ptr = __r._M_ptr;
_M_refcount = __r._M_refcount;
return *this;
}
__shared_ptr<_Tp, _Lp>
lock() const // never throws
{
#ifdef __GTHREADS
// Optimization: avoid throw overhead.
if (expired())
return __shared_ptr<element_type, _Lp>();
__try
{
return __shared_ptr<element_type, _Lp>(*this);
}
__catch(const bad_weak_ptr&)
{
// Q: How can we get here?
// A: Another thread may have invalidated r after the
// use_count test above.
return __shared_ptr<element_type, _Lp>();
}
#else
// Optimization: avoid try/catch overhead when single threaded.
return expired() ? __shared_ptr<element_type, _Lp>()
: __shared_ptr<element_type, _Lp>(*this);
#endif
} // XXX MT
long
use_count() const // never throws
{ return _M_refcount._M_get_use_count(); }
bool
expired() const // never throws
{ return _M_refcount._M_get_use_count() == 0; }
template<typename _Tp1>
bool
owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const
{ return _M_refcount._M_less(__rhs._M_refcount); }
template<typename _Tp1>
bool
owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const
{ return _M_refcount._M_less(__rhs._M_refcount); }
void
reset() // never throws
{ __weak_ptr().swap(*this); }
void
swap(__weak_ptr& __s) // never throws
{
std::swap(_M_ptr, __s._M_ptr);
_M_refcount._M_swap(__s._M_refcount);
}
// comparisons
template<typename _Tp1>
bool operator<(const __weak_ptr<_Tp1, _Lp>&) const = delete;
template<typename _Tp1>
bool operator<=(const __weak_ptr<_Tp1, _Lp>&) const = delete;
template<typename _Tp1>
bool operator>(const __weak_ptr<_Tp1, _Lp>&) const = delete;
template<typename _Tp1>
bool operator>=(const __weak_ptr<_Tp1, _Lp>&) const = delete;
private:
// Used by __enable_shared_from_this.
void
_M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount)
{
_M_ptr = __ptr;
_M_refcount = __refcount;
}
template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
friend class __enable_shared_from_this<_Tp, _Lp>;
friend class enable_shared_from_this<_Tp>;
_Tp* _M_ptr; // Contained pointer.
__weak_count<_Lp> _M_refcount; // Reference counter.
};
// 20.8.13.3.7 weak_ptr specialized algorithms.
template<typename _Tp, _Lock_policy _Lp>
inline void
swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b)
{ __a.swap(__b); }
/// owner_less
template<typename _Tp> struct owner_less;
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:
__enable_shared_from_this() { }
__enable_shared_from_this(const __enable_shared_from_this&) { }
__enable_shared_from_this&
operator=(const __enable_shared_from_this&)
{ return *this; }
~__enable_shared_from_this() { }
public:
__shared_ptr<_Tp, _Lp>
shared_from_this()
{ return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
__shared_ptr<const _Tp, _Lp>
shared_from_this() const
{ return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
private:
template<typename _Tp1>
void
_M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const
{ _M_weak_this._M_assign(__p, __n); }
template<typename _Tp1>
friend void
__enable_shared_from_this_helper(const __shared_count<_Lp>& __pn,
const __enable_shared_from_this* __pe,
const _Tp1* __px)
{
if (__pe != 0)
__pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
}
mutable __weak_ptr<_Tp, _Lp> _M_weak_this;
};
/**
* @brief A smart pointer with reference-counted copy semantics.
*
* The object pointed to is deleted when the last shared_ptr pointing to
* it is destroyed or reset.
*/
template<typename _Tp>
class shared_ptr
: public __shared_ptr<_Tp>
{
public:
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, typename _Deleter, typename _Alloc>
shared_ptr(_Tp1* __p, _Deleter __d, const _Alloc& __a)
: __shared_ptr<_Tp>(__p, __d, __a) { }
// Aliasing constructor
template<typename _Tp1>
shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p)
: __shared_ptr<_Tp>(__r, __p) { }
template<typename _Tp1>
shared_ptr(const shared_ptr<_Tp1>& __r)
: __shared_ptr<_Tp>(__r) { }
shared_ptr(shared_ptr&& __r)
: __shared_ptr<_Tp>(std::move(__r)) { }
template<typename _Tp1>
shared_ptr(shared_ptr<_Tp1>&& __r)
: __shared_ptr<_Tp>(std::move(__r)) { }
template<typename _Tp1>
explicit
shared_ptr(const weak_ptr<_Tp1>& __r)
: __shared_ptr<_Tp>(__r) { }
#if _GLIBCXX_DEPRECATED
template<typename _Tp1>
explicit
shared_ptr(std::auto_ptr<_Tp1>&& __r)
: __shared_ptr<_Tp>(std::move(__r)) { }
#endif
template<typename _Tp1, typename _Del>
explicit
shared_ptr(const std::unique_ptr<_Tp1, _Del>&) = delete;
template<typename _Tp1, typename _Del>
explicit
shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
: __shared_ptr<_Tp>(std::move(__r)) { }
template<typename _Tp1>
shared_ptr&
operator=(const shared_ptr<_Tp1>& __r) // never throws
{
this->__shared_ptr<_Tp>::operator=(__r);
return *this;
}
#if _GLIBCXX_DEPRECATED
template<typename _Tp1>
shared_ptr&
operator=(std::auto_ptr<_Tp1>&& __r)
{
this->__shared_ptr<_Tp>::operator=(std::move(__r));
return *this;
}
#endif
shared_ptr&
operator=(shared_ptr&& __r)
{
this->__shared_ptr<_Tp>::operator=(std::move(__r));
return *this;
}
template<class _Tp1>
shared_ptr&
operator=(shared_ptr<_Tp1>&& __r)
{
this->__shared_ptr<_Tp>::operator=(std::move(__r));
return *this;
}
template<typename _Tp1, typename _Del>
shared_ptr&
operator=(const std::unique_ptr<_Tp1, _Del>& __r) = delete;
template<typename _Tp1, typename _Del>
shared_ptr&
operator=(std::unique_ptr<_Tp1, _Del>&& __r)
{
this->__shared_ptr<_Tp>::operator=(std::move(__r));
return *this;
}
private:
// This constructor is non-standard, it is used by allocate_shared.
template<typename _Alloc, typename... _Args>
shared_ptr(_Sp_make_shared_tag __tag, _Alloc __a, _Args&&... __args)
: __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...)
{ }
template<typename _Tp1, typename _Alloc, typename... _Args>
friend shared_ptr<_Tp1>
allocate_shared(_Alloc __a, _Args&&... __args);
};
// 20.8.13.2.7 shared_ptr comparisons
template<typename _Tp1, typename _Tp2>
inline bool
operator==(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
{ return __a.get() == __b.get(); }
template<typename _Tp1, typename _Tp2>
inline bool
operator!=(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
{ return __a.get() != __b.get(); }
template<typename _Tp1, typename _Tp2>
inline bool
operator<(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b)
{ return __a.get() < __b.get(); }
template<typename _Tp>
struct less<shared_ptr<_Tp>>
: public _Sp_less<shared_ptr<_Tp>>
{ };
// 20.8.13.2.9 shared_ptr specialized algorithms.
template<typename _Tp>
inline void
swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b)
{ __a.swap(__b); }
// 20.8.13.2.10 shared_ptr casts.
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
static_pointer_cast(const shared_ptr<_Tp1>& __r)
{ return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); }
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
const_pointer_cast(const shared_ptr<_Tp1>& __r)
{ return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); }
template<typename _Tp, typename _Tp1>
inline shared_ptr<_Tp>
dynamic_pointer_cast(const shared_ptr<_Tp1>& __r)
{
if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
return shared_ptr<_Tp>(__r, __p);
return shared_ptr<_Tp>();
}
/**
* @brief A smart pointer with weak semantics.
*
* With forwarding constructors and assignment operators.
*/
template<typename _Tp>
class weak_ptr
: public __weak_ptr<_Tp>
{
public:
weak_ptr()
: __weak_ptr<_Tp>() { }
template<typename _Tp1>
weak_ptr(const weak_ptr<_Tp1>& __r)
: __weak_ptr<_Tp>(__r) { }
template<typename _Tp1>
weak_ptr(const shared_ptr<_Tp1>& __r)
: __weak_ptr<_Tp>(__r) { }
template<typename _Tp1>
weak_ptr&
operator=(const weak_ptr<_Tp1>& __r) // never throws
{
this->__weak_ptr<_Tp>::operator=(__r);
return *this;
}
template<typename _Tp1>
weak_ptr&
operator=(const shared_ptr<_Tp1>& __r) // never throws
{
this->__weak_ptr<_Tp>::operator=(__r);
return *this;
}
shared_ptr<_Tp>
lock() const // never throws
{
#ifdef __GTHREADS
if (this->expired())
return shared_ptr<_Tp>();
__try
{
return shared_ptr<_Tp>(*this);
}
__catch(const bad_weak_ptr&)
{
return shared_ptr<_Tp>();
}
#else
return this->expired() ? shared_ptr<_Tp>()
: shared_ptr<_Tp>(*this);
#endif
}
// comparisons
template<typename _Tp1>
bool operator<(const weak_ptr<_Tp1>&) const = delete;
template<typename _Tp1>
bool operator<=(const weak_ptr<_Tp1>&) const = delete;
template<typename _Tp1>
bool operator>(const weak_ptr<_Tp1>&) const = delete;
template<typename _Tp1>
bool operator>=(const weak_ptr<_Tp1>&) const = delete;
};
// 20.8.13.3.7 weak_ptr specialized algorithms.
template<typename _Tp>
inline void
swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b)
{ __a.swap(__b); }
/// owner_less
template<typename _Tp>
struct owner_less<shared_ptr<_Tp>>
: public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>>
{ };
template<typename _Tp>
struct owner_less<weak_ptr<_Tp>>
: public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>>
{ };
/**
* @brief Base class allowing use of member function shared_from_this.
*/
template<typename _Tp>
class enable_shared_from_this
{
protected:
enable_shared_from_this() { }
enable_shared_from_this(const enable_shared_from_this&) { }
enable_shared_from_this&
operator=(const enable_shared_from_this&)
{ return *this; }
~enable_shared_from_this() { }
public:
shared_ptr<_Tp>
shared_from_this()
{ return shared_ptr<_Tp>(this->_M_weak_this); }
shared_ptr<const _Tp>
shared_from_this() const
{ return shared_ptr<const _Tp>(this->_M_weak_this); }
private:
template<typename _Tp1>
void
_M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const
{ _M_weak_this._M_assign(__p, __n); }
template<typename _Tp1>
friend void
__enable_shared_from_this_helper(const __shared_count<>& __pn,
const enable_shared_from_this* __pe,
const _Tp1* __px)
{
if (__pe != 0)
__pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn);
}
mutable weak_ptr<_Tp> _M_weak_this;
};
template<typename _Tp, _Lock_policy _Lp, typename _Alloc, typename... _Args>
inline __shared_ptr<_Tp, _Lp>
__allocate_shared(_Alloc __a, _Args&&... __args)
{
return __shared_ptr<_Tp, _Lp>(_Sp_make_shared_tag(),
std::forward<_Alloc>(__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 __allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
std::forward<_Args>(__args)...);
}
/** @brief Create an object that is owned by a shared_ptr.
* @param __a An allocator.
* @param __args Arguments for the @a _Tp object's constructor.
* @return A shared_ptr that owns the newly created object.
* @throw An exception thrown from @a _Alloc::allocate or from the
* constructor of @a _Tp.
*
* A copy of @a __a will be used to allocate memory for the shared_ptr
* and the new object.
*/
template<typename _Tp, typename _Alloc, typename... _Args>
inline shared_ptr<_Tp>
allocate_shared(_Alloc __a, _Args&&... __args)
{
return shared_ptr<_Tp>(_Sp_make_shared_tag(), std::forward<_Alloc>(__a),
std::forward<_Args>(__args)...);
}
/** @brief Create an object that is owned by a shared_ptr.
* @param __args Arguments for the @a _Tp object's constructor.
* @return A shared_ptr that owns the newly created object.
* @throw std::bad_alloc, or an exception thrown from the
* constructor of @a _Tp.
*/
template<typename _Tp, typename... _Args>
inline shared_ptr<_Tp>
make_shared(_Args&&... __args)
{
typedef typename std::remove_const<_Tp>::type _Tp_nc;
return allocate_shared<_Tp>(std::allocator<_Tp_nc>(),
std::forward<_Args>(__args)...);
}
// @} group pointer_abstractions
_GLIBCXX_END_NAMESPACE
#endif // _SHARED_PTR_H
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