1 files changed, 81 insertions, 0 deletions
diff --git a/vcl/inc/impdel.hxx b/vcl/inc/impdel.hxx
new file mode 100644
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+++ b/vcl/inc/impdel.hxx
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_VCL_IMPDEL_HXX
+#define INCLUDED_VCL_IMPDEL_HXX
+
+#include <algorithm>
+#include <vector>
+
+namespace vcl
+{
+
+class DeletionListener;
+
+class DeletionNotifier
+{
+    std::vector< DeletionListener* > m_aListeners;
+    protected:
+    DeletionNotifier() {}
+
+    ~DeletionNotifier()
+    { notifyDelete(); }
+
+    inline void notifyDelete();
+
+    public:
+    void addDel( DeletionListener* pListener )
+    { m_aListeners.push_back( pListener ); }
+
+    void removeDel( DeletionListener* pListener )
+    { std::erase(m_aListeners, pListener); }
+};
+
+class DeletionListener
+{
+    DeletionNotifier*  m_pNotifier;
+    public:
+    DeletionListener( DeletionNotifier* pNotifier )
+    :  m_pNotifier( pNotifier )
+       {
+           if( m_pNotifier )
+               m_pNotifier->addDel( this );
+       }
+   ~DeletionListener()
+   {
+       if( m_pNotifier )
+           m_pNotifier->removeDel( this );
+   }
+   void deleted() { m_pNotifier = nullptr; }
+   bool isDeleted() const { return (m_pNotifier == nullptr); }
+};
+
+inline void DeletionNotifier::notifyDelete()
+{
+    for( auto& rListener : m_aListeners )
+       rListener->deleted();
+
+    m_aListeners.clear();
+}
+
+} // namespace vcl
+
+#endif // INCLUDED_VCL_IMPDEL_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */