92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
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/////////////////////////////////////////////////////////////////////////////
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// Name: wx/tracker.h
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// Purpose: Support class for object lifetime tracking (wxWeakRef<T>)
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// Author: Arne Steinarson
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// Created: 28 Dec 07
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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_TRACKER_H_
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#define _WX_TRACKER_H_
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#include "wx/defs.h"
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class wxEventConnectionRef;
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// This class represents an object tracker and is stored in a linked list
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// in the tracked object. It is only used in one of its derived forms.
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class WXDLLIMPEXP_BASE wxTrackerNode
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{
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public:
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wxTrackerNode() : m_nxt(NULL) { }
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virtual ~wxTrackerNode() { }
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virtual void OnObjectDestroy() = 0;
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virtual wxEventConnectionRef *ToEventConnection() { return NULL; }
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private:
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wxTrackerNode *m_nxt;
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friend class wxTrackable; // For list access
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friend class wxEvtHandler; // For list access
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};
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// Add-on base class for a trackable object.
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class WXDLLIMPEXP_BASE wxTrackable
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{
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public:
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void AddNode(wxTrackerNode *prn)
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{
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prn->m_nxt = m_first;
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m_first = prn;
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}
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void RemoveNode(wxTrackerNode *prn)
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{
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for ( wxTrackerNode **pprn = &m_first; *pprn; pprn = &(*pprn)->m_nxt )
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{
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if ( *pprn == prn )
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{
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*pprn = prn->m_nxt;
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return;
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}
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}
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wxFAIL_MSG( "removing invalid tracker node" );
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}
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wxTrackerNode *GetFirst() const { return m_first; }
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protected:
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// this class is only supposed to be used as a base class but never be
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// created nor destroyed directly so all ctors and dtor are protected
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wxTrackable() : m_first(NULL) { }
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// copy ctor and assignment operator intentionally do not copy m_first: the
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// objects which track the original trackable shouldn't track the new copy
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wxTrackable(const wxTrackable& WXUNUSED(other)) : m_first(NULL) { }
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wxTrackable& operator=(const wxTrackable& WXUNUSED(other)) { return *this; }
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// dtor is not virtual: this class is not supposed to be used
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// polymorphically and adding a virtual table to it would add unwanted
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// overhead
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~wxTrackable()
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{
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// Notify all registered refs
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while ( m_first )
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{
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wxTrackerNode * const first = m_first;
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m_first = first->m_nxt;
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first->OnObjectDestroy();
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}
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}
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wxTrackerNode *m_first;
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};
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#endif // _WX_TRACKER_H_
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