Thomas Geymayer
9975c751a7
- Add SGVirtualWeakReferenced to be used as base class for reference counted objects supporting weak references and virtual base classes. - Modify SGWeakPtr to copy with SGVirtualWeakReferenced objects.
99 lines
2.7 KiB
C++
99 lines
2.7 KiB
C++
// Copyright (C) 2004-2009 Mathias Froehlich - Mathias.Froehlich@web.de
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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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 GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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#ifndef SGWeakPtr_HXX
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#define SGWeakPtr_HXX
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#include "SGWeakReferenced.hxx"
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/**
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* Class for handling weak references to classes derived from SGWeakReferenced
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* or SGVirtualWeakReferenced.
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*/
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template<typename T>
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class SGWeakPtr {
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public:
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typedef T element_type;
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SGWeakPtr(void)
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{ }
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SGWeakPtr(const SGWeakPtr& p) : mWeakData(p.mWeakData)
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{ }
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SGWeakPtr(T* ptr)
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{ assign(ptr); }
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template<typename U>
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SGWeakPtr(const SGSharedPtr<U>& p)
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{ assign(p.get()); }
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template<typename U>
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SGWeakPtr(const SGWeakPtr<U>& p)
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{ SGSharedPtr<T> sharedPtr = p.lock(); assign(sharedPtr.get()); }
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~SGWeakPtr(void)
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{ }
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template<typename U>
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SGWeakPtr& operator=(const SGSharedPtr<U>& p)
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{ assign(p.get()); return *this; }
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template<typename U>
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SGWeakPtr& operator=(const SGWeakPtr<U>& p)
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{ SGSharedPtr<T> sharedPtr = p.lock(); assign(sharedPtr.get()); return *this; }
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SGWeakPtr& operator=(const SGWeakPtr& p)
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{ mWeakData = p.mWeakData; return *this; }
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template<typename U>
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bool operator==(const SGWeakPtr<U>& rhs) const
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{ return mWeakData == rhs.mWeakData; }
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template<typename U>
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bool operator!=(const SGWeakPtr<U>& rhs) const
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{ return mWeakData != rhs.mWeakData; }
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template<typename U>
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bool operator<(const SGWeakPtr<U>& rhs) const
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{ return mWeakData < rhs.mWeakData; }
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SGSharedPtr<T> lock(void) const
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{
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if (!mWeakData)
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return SGSharedPtr<T>();
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SGSharedPtr<T> sharedPtr;
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sharedPtr.assignNonRef(mWeakData->getPointer<T>());
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return sharedPtr;
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}
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bool expired() const
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{ return !mWeakData || mWeakData->mRefcount == 0; }
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void reset()
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{ mWeakData.reset(); }
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void clear()
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{ mWeakData.reset(); }
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void swap(SGWeakPtr& weakPtr)
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{ mWeakData.swap(weakPtr.mWeakData); }
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private:
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void assign(T* p)
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{
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if (p)
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mWeakData = p->mWeakData;
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else
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mWeakData = 0;
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}
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// The indirect reference itself.
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SGSharedPtr<SGWeakReferenced::WeakData> mWeakData;
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};
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#endif
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