notifier.h

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#ifndef _PNOTIFIER_H
#define _PNOTIFIER_H

#include <ptlib.h>
#include <ptlib/smartptr.h>

// General notification mechanism from one object to another

class PNotifierFunction : public PSmartObject
{
  PCLASSINFO(PNotifierFunction, PSmartObject);

  public:
    PNotifierFunction(
      void * obj    
    ) { object = PAssertNULL(obj); }

    virtual void Call(
      PObject & notifier,  
      INT extra            
    ) const = 0;

  protected:
    // Member variables
    void * object;
};


class PNotifier : public PSmartPointer
{
  PCLASSINFO(PNotifier, PSmartPointer);

  public:
    PNotifier(
      PNotifierFunction * func = NULL   
    ) : PSmartPointer(func) { }

    virtual void operator()(
      PObject & notifier,  
      INT extra            
    ) const {
      if (PAssertNULL(object) != NULL)
        ((PNotifierFunction*)object)->Call(notifier,extra);
    }
};


#define PDECLARE_NOTIFIER(notifier, notifiee, func) \
  class func##_PNotifier : public PNotifierFunction { \
    public: \
      func##_PNotifier(notifiee * obj) : PNotifierFunction(obj) { } \
      virtual void Call(PObject & note, INT extra) const \
        { ((notifiee*)object)->func((notifier &)note, extra); } \
  }; \
  friend class func##_PNotifier; \
  virtual void func(notifier & note, INT extra)

#define PCREATE_NOTIFIER2(obj, func) PNotifier(new func##_PNotifier(obj))

#define PCREATE_NOTIFIER(func) PCREATE_NOTIFIER2(this, func)

#endif

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