include/canvas/base/disambiguationhelper.hxx

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  19
  20 #ifndef INCLUDED_CANVAS_DISAMBIGUATIONHELPER_HXX
  21 #define INCLUDED_CANVAS_DISAMBIGUATIONHELPER_HXX
  22
  23 #include <osl/mutex.hxx>
  24
  25
  26 /* Definition of the DisambiguationHelper class */
  27
  28 namespace canvas
  29 {
  30     /** Base class, initializing its own baseclass with m_aMutex.
  31
  32         This is necessary to make the CanvasBase, GraphicDeviceBase,
  33         etc. classes freely combinable - letting them perform this
  34         initialization would prohibit deriving e.g. CanvasBase from
  35         GraphicDeviceBase.
  36
  37         On top of that, disambiguates XEventListener::disposing and
  38         WeakComponentImplHelper::disposing.
  39
  40         Having two virtual methods with the same name, and not
  41         overriding them in every derived class, will hide one of
  42         them. Later trying to override the same method, will generate
  43         a new vtable slot, and lead to very hard to spot errors.
  44      */
  45     template< class Base > class DisambiguationHelper : public Base
  46     {
  47     public:
  48         typedef Base BaseType;
  49
  50         /** Construct DisambiguationHelper
  51
  52             This method is the whole purpose of this template:
  53             initializing a base class with the provided m_aMutex
  54             member (the WeakComponentImplHelper templates need that,
  55             as they require the lifetime of the mutex to extend
  56             theirs).
  57          */
  58         DisambiguationHelper() :
  59             BaseType( m_aMutex )
  60         {
  61         }
  62
  63         virtual void SAL_CALL disposing()
  64         { disposeThis(); }
  65
  66         virtual void SAL_CALL disposing( const ::com::sun::star::lang::EventObject& Source ) throw (::com::sun::star::uno::RuntimeException)
  67         { disposeEventSource(Source); }
  68
  69         virtual void disposeThis()
  70         {}
  71         virtual void disposeEventSource( const ::com::sun::star::lang::EventObject& ) throw (::com::sun::star::uno::RuntimeException)
  72         {}
  73
  74 protected:
  75         mutable ::osl::Mutex m_aMutex;
  76     };
  77 }
  78
  79 #endif /* INCLUDED_CANVAS_DISAMBIGUATIONHELPER_HXX */
  80
  81 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */