ResInsight/cafProjectDataModel/cafPdmPointer.h
2012-05-18 09:45:23 +02:00

82 lines
4.2 KiB
C++

//##################################################################################################
//
// Custom Visualization Core library
// Copyright (C) 2011-2012 Ceetron AS
//
// 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 of the License, 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 at <<http://www.gnu.org/licenses/gpl.html>>
// for more details.
//
//##################################################################################################
#pragma once
namespace caf
{
class PdmObject;
//==================================================================================================
/// Helper class for the PdmPointer class
/// The add and removing of references is put into a pure static class to
/// resolve circular include problems.
//
/// Overall idea of the referencing system:
/// The addressToObjectPointer is added to a std::set in the object pointed to.
/// when the object pointed to is deleted, its destructor sets the object pointers
/// it has addresses to to NULL
//==================================================================================================
class PdmPointerImpl
{
private:
template < class T > friend class PdmPointer;
static void addReference(PdmObject ** addressToObjectPointer);
static void removeReference(PdmObject ** addressToObjectPointer);
};
//==================================================================================================
/// Guarded pointer class to point at PdmObjects
/// Use a PdmPointer<SomePdmObject> in the same way as a normal pointer.
/// The guarding sets the pointer to NULL if the object pointed to dies
///
/// NOTE: This is not reference counting. The user is responsible to delete the objects pointed to.
/// It _can_ be used together with the cvf::ref system if neccesary (this is no recomendation)
//==================================================================================================
template < class T >
class PdmPointer
{
PdmObject* m_object;
public :
inline PdmPointer () : m_object(NULL) { }
inline PdmPointer ( T * p ) : m_object(p) { PdmPointerImpl::addReference(&m_object); }
inline PdmPointer ( const PdmPointer<T> & p ) : m_object ( p.m_object )
{ PdmPointerImpl::addReference(&m_object); }
inline ~PdmPointer () { PdmPointerImpl::removeReference(&m_object); }
T* p() const { return static_cast<T*>(const_cast<PdmObject*>(m_object)); }
bool isNull() const { return !m_object; }
bool notNull() const { return !isNull(); }
operator T* () const { return static_cast<T*>(const_cast<PdmObject*>(m_object)); }
T& operator* () const { return *static_cast<T*>(const_cast<PdmObject*>(m_object)); }
T* operator->() const { return static_cast<T*>(const_cast<PdmObject*>(m_object)); }
PdmPointer<T> & operator= ( const PdmPointer<T>& p ) { if (this != &p) PdmPointerImpl::removeReference(&m_object); m_object = p.m_object; PdmPointerImpl::addReference(&m_object); return *this; }
PdmPointer<T> & operator= ( T* p ) { if (m_object != p) PdmPointerImpl::removeReference(&m_object); m_object = p; PdmPointerImpl::addReference(&m_object); return *this; }
// Private methods used by PdmField<T*> and PdmPointersField<T*>. Do not use unless you mean it !
PdmObject* rawPtr() const { return m_object; }
void setRawPtr( PdmObject* p) { if (m_object != p) PdmPointerImpl::removeReference(&m_object); m_object = p; PdmPointerImpl::addReference(&m_object); }
};
} // End of namespace caf