7f2468e96a
wxWeakRef can work with forward-declared classes provided dynamic_cast<> is available but this wasn't detected as being the case due to the use of the obsolete HAVE_DYNAMIC_CAST in its code. Replace HAVE_DYNAMIC_CAST with !wxNO_RTTI to fix this. Also add a unit test checking that this does work. Closes #11916. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63986 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
354 lines
8.7 KiB
C++
354 lines
8.7 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: wx/weakref.h
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// Purpose: wxWeakRef - Generic weak references for wxWidgets
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// Author: Arne Steinarson
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// Created: 27 Dec 07
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// RCS-ID: $Id$
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// Copyright: (c) 2007 Arne Steinarson
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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#ifndef _WX_WEAKREF_H_
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#define _WX_WEAKREF_H_
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#include "wx/tracker.h"
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// Some compilers (VC6, Borland, g++ < 3.3) have problem with template specialization.
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// However, this is only used for optimization purposes (a smaller wxWeakRef pointer)
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// (and the corner case of wxWeakRef<wxObject>). So for those compilers, we can fall
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// back to the non-optimal case, where we use a the same type of weak ref (static one)
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// in all cases. See defs.h for various setting these defines depending on compiler.
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#if !defined(HAVE_PARTIAL_SPECIALIZATION) || \
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!defined(HAVE_TEMPLATE_OVERLOAD_RESOLUTION) || \
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(defined(__GNUC__) && !wxCHECK_GCC_VERSION(3, 3))
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#define USE_ONLY_STATIC_WEAKREF
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#endif
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#ifndef USE_ONLY_STATIC_WEAKREF
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// Avoid including this for simpler compilers
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#include "wx/meta/convertible.h"
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#include "wx/meta/int2type.h"
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template <class T>
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struct wxIsStaticTrackable
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{
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enum { value = wxConvertibleTo<T, wxTrackable>::value };
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};
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#endif // !USE_ONLY_STATIC_WEAKREF
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// Weak ref implementation when T has wxTrackable as a known base class
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template <class T>
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class wxWeakRefStatic : public wxTrackerNode
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{
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public:
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wxWeakRefStatic() : m_pobj(NULL) { }
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void Release()
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{
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// Release old object if any
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if ( m_pobj )
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{
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// Remove ourselves from object tracker list
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wxTrackable *pt = static_cast<wxTrackable*>(m_pobj);
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pt->RemoveNode(this);
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m_pobj = NULL;
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}
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}
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virtual void OnObjectDestroy()
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{
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// Tracked object itself removes us from list of trackers
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wxASSERT(m_pobj != NULL);
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m_pobj = NULL;
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}
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protected:
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void Assign(T* pobj)
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{
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if ( m_pobj == pobj )
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return;
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Release();
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// Now set new trackable object
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if ( pobj )
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{
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// Add ourselves to object tracker list
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wxTrackable *pt = static_cast<wxTrackable*>(pobj);
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pt->AddNode(this);
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m_pobj = pobj;
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}
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}
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void AssignCopy(const wxWeakRefStatic& wr)
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{
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Assign( wr.m_pobj );
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}
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T *m_pobj;
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};
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#ifndef USE_ONLY_STATIC_WEAKREF
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template<class T,bool use_static>
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struct wxWeakRefImpl;
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// Intermediate class, to select the static case above.
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template <class T>
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struct wxWeakRefImpl<T, true> : public wxWeakRefStatic<T>
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{
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enum { value = 1 };
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};
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// Weak ref implementation when T does not have wxTrackable as known base class
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template<class T>
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struct wxWeakRefImpl<T, false> : public wxTrackerNode
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{
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void Release()
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{
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// Release old object if any
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if ( m_pobj )
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{
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// Remove ourselves from object tracker list
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m_ptbase->RemoveNode(this);
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m_pobj = NULL;
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m_ptbase = NULL;
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}
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}
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virtual void OnObjectDestroy()
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{
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// Tracked object itself removes us from list of trackers
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wxASSERT(m_pobj != NULL);
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m_pobj = NULL;
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m_ptbase = NULL;
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}
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protected:
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wxWeakRefImpl() : m_pobj(NULL), m_ptbase(NULL) { }
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// Assign receives most derived class here and can use that
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template <class TDerived>
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void Assign( TDerived* pobj )
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{
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AssignHelper( pobj, wxInt2Type<wxIsStaticTrackable<TDerived>::value>() );
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}
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template <class TDerived>
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void AssignHelper(TDerived* pobj, wxInt2Type<true>)
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{
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wxTrackable *ptbase = static_cast<wxTrackable*>(pobj);
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DoAssign( pobj, ptbase );
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}
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#ifndef wxNO_RTTI
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void AssignHelper(T* pobj, wxInt2Type<false>)
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{
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// A last way to get a trackable pointer
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wxTrackable *ptbase = dynamic_cast<wxTrackable*>(pobj);
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if ( ptbase )
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{
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DoAssign( pobj, ptbase );
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}
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else
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{
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wxFAIL_MSG( "Tracked class should inherit from wxTrackable" );
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Release();
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}
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}
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#endif // RTTI enabled
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void AssignCopy(const wxWeakRefImpl& wr)
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{
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DoAssign(wr.m_pobj, wr.m_ptbase);
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}
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void DoAssign( T* pobj, wxTrackable *ptbase ) {
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if( m_pobj==pobj ) return;
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Release();
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// Now set new trackable object
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if( pobj )
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{
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// Add ourselves to object tracker list
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wxASSERT( ptbase );
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ptbase->AddNode( this );
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m_pobj = pobj;
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m_ptbase = ptbase;
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}
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}
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T *m_pobj;
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wxTrackable *m_ptbase;
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};
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#endif // #ifndef USE_ONLY_STATIC_WEAKREF
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// A weak reference to an object of type T, where T has base wxTrackable
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// (usually statically but if not dynamic_cast<> is tried).
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template <class T>
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class wxWeakRef : public
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#ifdef USE_ONLY_STATIC_WEAKREF
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wxWeakRefStatic<T>
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#else
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wxWeakRefImpl<T, wxIsStaticTrackable<T>::value != 0>
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#endif
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{
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public:
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typedef T element_type;
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// Default ctor
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wxWeakRef() { }
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// Enabling this ctor for VC6 results in mysterious compilation failures in
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// wx/window.h when assigning wxWindow pointers (FIXME-VC6)
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#ifndef __VISUALC6__
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// Ctor from the object of this type: this is needed as the template ctor
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// below is not used by at least g++4 when a literal NULL is used
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wxWeakRef(T *pobj)
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{
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Assign(pobj);
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}
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#endif // !__VISUALC6__
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// When we have the full type here, static_cast<> will always work
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// (or give a straight compiler error).
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template <class TDerived>
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wxWeakRef(TDerived* pobj)
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{
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Assign(pobj);
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}
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// We need this copy ctor, since otherwise a default compiler (binary) copy
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// happens (if embedded as an object member).
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wxWeakRef(const wxWeakRef<T>& wr)
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{
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Assign(wr.get());
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}
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wxWeakRef<T>& operator=(const wxWeakRef<T>& wr)
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{
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AssignCopy(wr);
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return *this;
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}
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virtual ~wxWeakRef() { this->Release(); }
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// Smart pointer functions
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T& operator*() const { return *this->m_pobj; }
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T* operator->() const { return this->m_pobj; }
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T* get() const { return this->m_pobj; }
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operator T*() const { return this->m_pobj; }
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};
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#ifndef wxNO_RTTI
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// Weak ref implementation assign objects are queried for wxTrackable
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// using dynamic_cast<>
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template <class T>
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class wxWeakRefDynamic : public wxTrackerNode
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{
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public:
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wxWeakRefDynamic() : m_pobj(NULL) { }
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wxWeakRefDynamic(T* pobj) : m_pobj(pobj)
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{
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Assign(pobj);
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}
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wxWeakRefDynamic(const wxWeakRef<T>& wr)
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{
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Assign(wr.get());
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}
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virtual ~wxWeakRefDynamic() { Release(); }
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// Smart pointer functions
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T& operator*() const { wxASSERT(m_pobj); return *m_pobj; }
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T* operator->() const { wxASSERT(m_pobj); return m_pobj; }
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T* get() const { return m_pobj; }
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operator T* () const { return m_pobj; }
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T* operator = (T* pobj) { Assign(pobj); return m_pobj; }
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// Assign from another weak ref, point to same object
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T* operator = (const wxWeakRef<T> &wr) { Assign( wr.get() ); return m_pobj; }
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void Release()
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{
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// Release old object if any
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if( m_pobj )
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{
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// Remove ourselves from object tracker list
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wxTrackable *pt = dynamic_cast<wxTrackable*>(m_pobj);
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wxASSERT(pt);
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pt->RemoveNode(this);
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m_pobj = NULL;
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}
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}
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virtual void OnObjectDestroy()
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{
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wxASSERT_MSG(m_pobj, "tracked object should have removed us itself");
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m_pobj = NULL;
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}
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protected:
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void Assign(T *pobj)
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{
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if ( m_pobj == pobj )
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return;
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Release();
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// Now set new trackable object
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if ( pobj )
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{
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// Add ourselves to object tracker list
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wxTrackable *pt = dynamic_cast<wxTrackable*>(pobj);
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if ( pt )
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{
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pt->AddNode(this);
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m_pobj = pobj;
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}
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else
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{
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// If the object we want to track does not support wxTackable, then
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// log a message and keep the NULL object pointer.
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wxFAIL_MSG( "Tracked class should inherit from wxTrackable" );
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}
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}
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}
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T *m_pobj;
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};
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#endif // RTTI enabled
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// Provide some basic types of weak references
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class WXDLLIMPEXP_FWD_BASE wxEvtHandler;
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class WXDLLIMPEXP_FWD_CORE wxWindow;
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typedef wxWeakRef<wxEvtHandler> wxEvtHandlerRef;
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typedef wxWeakRef<wxWindow> wxWindowRef;
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#endif // _WX_WEAKREF_H_
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