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improvements to wxWeakRef and related classes

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51187 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Vadim Zeitlin
2008-01-13 01:12:13 +00:00
parent 0fb0ecc452
commit cc6ceca789
12 changed files with 983 additions and 309 deletions
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338
include/wx/weakref.h
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@@ -2,7 +2,7 @@
// Name: wx/weakref.h
// Purpose: wxWeakRef - Generic weak references for wxWidgets
// Author: Arne Steinarson
// Created: 2007-12-27
// Created: 27 Dec 07
// RCS-ID: $Id$
// Copyright: (c) 2007 Arne Steinarson
// Licence: wxWindows licence
@@ -11,19 +11,243 @@
#ifndef _WX_WEAKREF_H_
#define _WX_WEAKREF_H_
#include <wx/tracker.h>
#include "wx/tracker.h"
// A weak reference to an object of type T, where T has type wxTrackable
// as one of its base classes (in a static or dynamic sense).
template<class T>
class wxWeakRef : public wxTrackerNode
#include "wx/meta/convertible.h"
#include "wx/meta/int2type.h"
template <class T>
struct wxIsStaticTrackable
{
enum { value = wxConvertibleTo<T, wxTrackable>::value };
};
// Weak ref implementation when T has wxTrackable as a known base class
template <class T>
class wxWeakRefStatic : public wxTrackerNode
{
public:
typedef T element_type;
wxWeakRef(T *pobj = NULL) : m_pobj(NULL) { Assign(pobj); }
wxWeakRefStatic() : m_pobj(NULL) { }
virtual ~wxWeakRef() { Assign(NULL); }
void Release()
{
// Release old object if any
if ( m_pobj )
{
// Remove ourselves from object tracker list
wxTrackable *pt = static_cast<wxTrackable*>(m_pobj);
pt->RemoveNode(this);
m_pobj = NULL;
}
}
protected:
void Assign(T* pobj)
{
if ( m_pobj == pobj )
return;
Release();
// Now set new trackable object
if ( pobj )
{
// Add ourselves to object tracker list
wxTrackable *pt = static_cast<wxTrackable*>(pobj);
pt->AddNode(this);
m_pobj = pobj;
}
}
void AssignCopy( const wxWeakRefStatic& wr )
{
Assign( wr.m_pobj );
}
virtual void OnObjectDestroy()
{
// Tracked object itself removes us from list of trackers
wxASSERT( m_pobj!=NULL );
m_pobj = NULL;
}
T *m_pobj;
};
#ifdef HAVE_PARTIAL_SPECIALIZATION
template<class T,bool use_static>
struct wxWeakRefImpl;
// Intermediate class, to select the static case above.
template <class T>
struct wxWeakRefImpl<T, true> : public wxWeakRefStatic<T>
{
enum { value = 1 };
};
// Weak ref implementation when T does not have wxTrackable as known base class
template<class T>
struct wxWeakRefImpl<T, false> : public wxTrackerNode
{
void Release()
{
// Release old object if any
if ( m_pobj )
{
// Remove ourselves from object tracker list
m_ptbase->RemoveNode(this);
m_pobj = NULL;
m_ptbase = NULL;
}
}
protected:
wxWeakRefImpl() : m_pobj(NULL), m_ptbase(NULL) { }
// Assign receives most derived class here and can use that
template <class TDerived>
void Assign( TDerived* pobj )
{
AssignHelper( pobj, wxInt2Type<wxIsStaticTrackable<TDerived>::value>() );
}
template <class TDerived>
void AssignHelper(TDerived* pobj, wxInt2Type<true>)
{
wxTrackable *ptbase = static_cast<wxTrackable*>(pobj);
DoAssign( pobj, ptbase );
}
#ifdef HAVE_DYNAMIC_CAST
void AssignHelper(T* pobj, wxInt2Type<false>)
{
// A last way to get a trackable pointer
wxTrackable *ptbase = dynamic_cast<wxTrackable*>(pobj);
if ( ptbase )
{
DoAssign( pobj, ptbase );
}
else
{
wxFAIL_MSG( "Tracked class should inherit from wxTrackable" );
Release();
}
}
#endif // HAVE_DYNAMIC_CAST
void AssignCopy(const wxWeakRefImpl& wr)
{
DoAssign( wr.m_pobj, wr.m_ptbase );
}
void DoAssign( T* pobj, wxTrackable *ptbase ) {
if( m_pobj==pobj ) return;
Release();
// Now set new trackable object
if( pobj )
{
// Add ourselves to object tracker list
wxASSERT( ptbase );
ptbase->AddNode( this );
m_pobj = pobj;
m_ptbase = ptbase;
}
}
virtual void OnObjectDestroy()
{
// Tracked object itself removes us from list of trackers
wxASSERT( m_pobj!=NULL );
m_pobj = NULL;
m_ptbase = NULL;
}
T *m_pobj;
wxTrackable *m_ptbase;
};
#endif // HAVE_PARTIAL_SPECIALIZATION
// A weak reference to an object of type T, where T has type wxTrackable
// (usually statically but if not dynamic_cast<> is tried).
template <class T>
class wxWeakRef : public
#ifdef HAVE_PARTIAL_SPECIALIZATION
wxWeakRefImpl<T, wxIsStaticTrackable<T>::value>
#else
wxWeakRefStatic<T>
#endif
{
public:
// Default ctor
wxWeakRef() { }
// When we have the full type here, static_cast<> will always work
// (or give a straight compiler error).
template <class TDerived>
wxWeakRef(TDerived* pobj)
{
Assign(pobj);
}
template <class TDerived>
wxWeakRef<T>& operator=(TDerived* pobj)
{
Assign(pobj);
return *this;
}
wxWeakRef<T>& operator=(const wxWeakRef<T>& wr)
{
AssignCopy(wr);
return *this;
}
virtual ~wxWeakRef() { Release(); }
// Smart pointer functions
T& operator*() const { return *m_pobj; }
T* operator->() const { return m_pobj; }
T* get() const { return m_pobj; }
// test for pointer validity: defining conversion to unspecified_bool_type
// and not more obvious bool to avoid implicit conversions to integer types
typedef T *(wxWeakRef<T>::*unspecified_bool_type)() const;
operator unspecified_bool_type() const
{
return this->m_pobj ? &wxWeakRef<T>::get : NULL;
}
};
// Weak ref implementation assign objects are queried for wxTrackable
// using dynamic_cast<>
template<class T>
class wxWeakRefDynamic : public wxTrackerNode
{
public:
wxWeakRefDynamic() : m_pobj(NULL) { }
wxWeakRefDynamic(T* pobj) : m_pobj(pobj)
{
Assign(pobj);
}
virtual ~wxWeakRefDynamic() { Release(); }
// Smart pointer functions
T& operator * (){ wxASSERT(this->m_pobj); return *m_pobj; }
T* operator -> (){ wxASSERT(this->m_pobj); return m_pobj; }
T* operator = (T* pobj) { Assign(pobj); return m_pobj; }
T* get(){ return this->m_pobj; }
// operator T* (){ return this->m_pobj; }
// test for pointer validity: defining conversion to unspecified_bool_type
// and not more obvious bool to avoid implicit conversions to integer types
@@ -33,92 +257,68 @@ public:
return m_pobj ? &wxWeakRef<T>::get : NULL;
}
T * get() const
{
return m_pobj;
}
T* operator->()
{
wxASSERT(m_pobj != NULL);
return m_pobj;
}
T& operator*() const
{
wxASSERT(m_pobj != NULL);
return *m_pobj;
}
T* operator=(T *pobj)
{
Assign(pobj);
return m_pobj;
}
// Assign from another weak ref, point to same object
T* operator = (const wxWeakRef<T> &wr)
{
Assign(wr);
return m_pobj;
}
virtual void OnObjectDestroy()
T* operator = (const wxWeakRef<T> &wr) { Assign( wr.get() ); return this->m_pobj; }
void Release()
{
// Tracked object itself removes us from list of trackers
wxASSERT( m_pobj );
m_pobj = NULL;
}
protected:
friend class wxTrackableBase;
friend class wxEvtHandler;
virtual wxTrackerNodeType GetType() { return WeakRef; }
void Assign(T* pobj)
{
if ( m_pobj == pobj )
return;
// First release old object if any
if ( m_pobj )
// Release old object if any
if( m_pobj )
{
// Remove ourselves from object tracker list
// This does static_cast if available, otherwise it tries dynamic cast
wxTrackableBase *pt = wxTrackableCaster<T,wxHasBase<T,wxTrackableBase>::value >::Cast(m_pobj);
wxTrackable *pt = dynamic_cast<wxTrackable*>(m_pobj);
wxASSERT(pt);
pt->RemoveNode(this);
m_pobj = NULL;
}
}
protected:
void Assign(T *pobj)
{
if ( m_pobj == pobj )
return;
Release();
// Now set new trackable object
if ( pobj )
{
wxTrackableBase *pt = wxTrackableCaster<T,wxHasBase<T,wxTrackableBase>::value >::Cast(pobj);
if( pt )
// Add ourselves to object tracker list
wxTrackable *pt = dynamic_cast<wxTrackable*>(pobj);
if ( pt )
{
pt->AddNode( this );
pt->AddNode(this);
m_pobj = pobj;
}
else
{
// If the tracked we want to track does not support wxTackableBase, then
// log a message and keep the NULL object pointer.
wxLogWarning( _T("wxWeakRef::Assign - Type does not provide wxTrackableBase - resetting tracked object") );
// If the object we want to track does not support wxTackable, then
// log a message and keep the NULL object pointer.
wxFAIL_MSG( "Tracked class should inherit from wxTrackable" );
}
}
}
void AssignCopy(const wxWeakRefDynamic& wr)
{
Assign(wr.m_pobj);
}
virtual void OnObjectDestroy()
{
wxASSERT_MSG( m_pobj, "tracked object should have removed us itself" );
m_pobj = NULL;
}
T *m_pobj;
};
// Provide some basic types of weak references
class WXDLLIMPEXP_FWD_BASE wxObject;
class WXDLLIMPEXP_FWD_BASE wxEvtHandler;
class WXDLLIMPEXP_FWD_CORE wxWindow;
class WXDLLIMPEXP_FWD_BASE wxWindow;
typedef wxWeakRef<wxObject> wxObjectRef;
typedef wxWeakRef<wxEvtHandler> wxEvtHandlerRef;
typedef wxWeakRef<wxWindow> wxWindowRef;