tb_widgets_listener.h

// ================================================================================
// ==      This file is a part of Turbo Badger. (C) 2011-2014, Emil Segerås      ==
// ==                     See tb_core.h for more information.                    ==
// ================================================================================

#ifndef TB_WIDGETSLISTENER_H
#define TB_WIDGETSLISTENER_H

#include "tb_core.h"
#include "tb_linklist.h"
#include "tb_widgets.h"

namespace tb {

class TBWidget;

class TBWidgetListenerGlobalLink : public TBLinkOf<TBWidgetListenerGlobalLink> { };

class TBWidgetListener : public TBLinkOf<TBWidgetListener>, public TBWidgetListenerGlobalLink
{
public:
    static void AddGlobalListener(TBWidgetListener *listener);
    static void RemoveGlobalListener(TBWidgetListener *listener);

    virtual void OnWidgetDelete(TBWidget * /*widget*/) {}

    virtual bool OnWidgetDying(TBWidget * /*widget*/) { return false; }

    virtual void OnWidgetAdded(TBWidget * /*parent*/, TBWidget * /*child*/) {}

    virtual void OnWidgetRemove(TBWidget * /*parent*/, TBWidget * /*child*/) {}

    virtual void OnWidgetFocusChanged(TBWidget * /*widget*/, bool /*focused*/) {}

    virtual bool OnWidgetInvokeEvent(TBWidget * /*widget*/, const TBWidgetEvent & /*ev*/) { return false; }
private:
    friend class TBWidget;
    static void InvokeWidgetDelete(TBWidget *widget);
    static bool InvokeWidgetDying(TBWidget *widget);
    static void InvokeWidgetAdded(TBWidget *parent, TBWidget *child);
    static void InvokeWidgetRemove(TBWidget *parent, TBWidget *child);
    static void InvokeWidgetFocusChanged(TBWidget *widget, bool focused);
    static bool InvokeWidgetInvokeEvent(TBWidget *widget, const TBWidgetEvent &ev);
};

class TBWidgetSafePointer : private TBWidgetListener
{
public:
    TBWidgetSafePointer() : m_widget(nullptr)                   { }
    TBWidgetSafePointer(TBWidget *widget) : m_widget(nullptr)   { Set(widget); }
    ~TBWidgetSafePointer()                                      { Set(nullptr); }

    void Set(TBWidget *widget);

    TBWidget *Get() const { return m_widget; }
private:
    virtual void OnWidgetDelete(TBWidget *widget);
    TBWidget *m_widget;
};

} // namespace tb

#endif // TB_WIDGETSLISTENER_H