wxWidgets/include/wx/clntdata.h

/////////////////////////////////////////////////////////////////////////////
// Name:        wx/clntdata.h
// Purpose:     A mixin class for holding a wxClientData or void pointer
// Author:      Robin Dunn
// Modified by:
// Created:     9-Oct-2001
// RCS-ID:      $Id$
// Copyright:   (c) wxWindows team
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#ifndef _WX_CLNTDATAH__
#define _WX_CLNTDATAH__

#ifdef __GNUG__
    #pragma interface "clntdata.h"
#endif

#include "wx/defs.h"
#include "wx/string.h"

// ----------------------------------------------------------------------------

// what kind of client data do we have?
enum wxClientDataType
{
    wxClientData_None,    // we don't know yet because we don't have it at all
    wxClientData_Object,  // our client data is typed and we own it
    wxClientData_Void     // client data is untyped and we don't own it
};

class WXDLLEXPORT wxClientData
{
public:
    wxClientData() { }
    virtual ~wxClientData() { }
};

class WXDLLEXPORT wxStringClientData : public wxClientData
{
public:
    wxStringClientData() : m_data() { }
    wxStringClientData( const wxString &data ) : m_data(data) { }
    void SetData( const wxString &data ) { m_data = data; }
    const wxString& GetData() const { return m_data; }

private:
    wxString  m_data;
};



// This class is a mixin that provides storage and management of "client
// data."  The client data stored can either be a pointer to a wxClientData
// object in which case it is managed by the container (i.e.  it will delete
// the data when it's destroyed) or an untyped pointer which won't be deleted
// by the container - but not both of them
//
// NOTE:  This functionality is currently duplicated in wxEvtHandler in order
//        to avoid having more than one vtable in that class heirachy.

class WXDLLEXPORT wxClientDataContainer
{
public:
    wxClientDataContainer();
    virtual ~wxClientDataContainer();

    void SetClientObject( wxClientData *data ) { DoSetClientObject(data); }
    wxClientData *GetClientObject() const { return DoGetClientObject(); }

    void SetClientData( void *data ) { DoSetClientData(data); }
    void *GetClientData() const { return DoGetClientData(); }

protected:
    // The user data: either an object which will be deleted by the container
    // when it's deleted or some raw pointer which we do nothing with - only
    // one type of data can be used with the given window (i.e. you cannot set
    // the void data and then associate the container with wxClientData or vice
    // versa)
    union
    {
        wxClientData *m_clientObject;
        void         *m_clientData;
    };

    // client data accessors
    virtual void DoSetClientObject( wxClientData *data );
    virtual wxClientData *DoGetClientObject() const;

    virtual void DoSetClientData( void *data );
    virtual void *DoGetClientData() const;

    // what kind of data do we have?
    wxClientDataType m_clientDataType;

};

// ----------------------------------------------------------------------------
#endif