notifier.h

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/*
 * notifier.h
 *
 * Notified type safe function pointer class.
 *
 * Portable Tools Library
 *
 * Copyright (c) 1993-1998 Equivalence Pty. Ltd.
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Portable Windows Library.
 *
 * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
 *
 * Contributor(s): ______________________________________.
 */

#ifndef PTLIB_NOTIFIER_H
#define PTLIB_NOTIFIER_H

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

// General notification mechanism from one object to another

template <typename ParamType>
class PNotifierFunctionTemplate : public PSmartObject
{
  PCLASSINFO(PNotifierFunctionTemplate, PSmartObject);

  protected:
    PNotifierFunctionTemplate(
      void * target,    
      void * = NULL
    ) { m_target = PAssertNULL(target); }

  public:
    virtual void Call(
      PObject & notifier,  
      ParamType extra       
    ) const = 0;

    virtual void * GetTarget() const { return this->m_target; }

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

typedef PNotifierFunctionTemplate<P_INT_PTR> PNotifierFunction;


template <typename ParamType>
class PNotifierTemplate : public PSmartPointer
{
  PCLASSINFO(PNotifierTemplate, PSmartPointer);

  public:
    typedef PNotifierFunctionTemplate<ParamType> * FunctionPtr;

    PNotifierTemplate(
      FunctionPtr func = NULL   
    ) : PSmartPointer(func) { }

    virtual void operator()(
      PObject & notifier,  
      ParamType extra       
    ) const {
      FunctionPtr ptr = dynamic_cast<FunctionPtr>(GetObject());
      if (PAssertNULL(ptr) != NULL)
        ptr->Call(notifier, extra);
    }

    void * GetTarget() const
    {
      FunctionPtr ptr = dynamic_cast<FunctionPtr>(GetObject());
      return ptr != NULL ? ptr->GetTarget() : NULL;
    }
};

typedef PNotifierTemplate<P_INT_PTR> PNotifier;


#define PDECLARE_NOTIFIER_COMMON1(notifierType, notifiee, func, ParamType, BaseClass) \
  class func##_PNotifier : public BaseClass { \
    public: \
      func##_PNotifier(notifiee * target) : BaseClass(target, target) { } \
      virtual void Call(PObject & note, ParamType extra) const \

#define PDECLARE_NOTIFIER_COMMON2(notifierType, notifierArg, notifiee, func, ParamType, ParamArg, BaseClass) \
        { notifiee * target = reinterpret_cast<notifiee *>(this->GetTarget()); \
          if (target != NULL) \
            target->func(reinterpret_cast<notifierType &>(note), extra); \
        } \
      static PNotifierTemplate<ParamType> Create(notifiee * obj) { return new func##_PNotifier(obj); } \
      static PNotifierTemplate<ParamType> Create(notifiee & obj) { return new func##_PNotifier(&obj); } \
  }; \
  friend class func##_PNotifier; \
  virtual void func(notifierType & notifierArg, ParamType ParamArg) \

#define PDECLARE_NOTIFIER_COMMON(notifierType, notifierArg, notifiee, func, ParamType, ParamArg, BaseClass) \
       PDECLARE_NOTIFIER_COMMON1(notifierType, notifiee, func, ParamType, BaseClass) \
       PDECLARE_NOTIFIER_COMMON2(notifierType, notifierArg, notifiee, func, ParamType, ParamArg, BaseClass)


#define PDECLARE_NOTIFIER_EXT(notifierType, notifierArg, notifiee, func, ParamType, ParamArg) \
     PDECLARE_NOTIFIER_COMMON(notifierType, notifierArg, notifiee, func, ParamType, ParamArg, PNotifierFunctionTemplate<ParamType>)

#define PDECLARE_NOTIFIER2(notifierType,   notifiee, func, ParamType  ) \
     PDECLARE_NOTIFIER_EXT(notifierType, , notifiee, func, ParamType, )

#define PDECLARE_NOTIFIER(notifierType, notifiee, func) \
       PDECLARE_NOTIFIER2(notifierType, notifiee, func, P_INT_PTR)


#define PCREATE_NOTIFIER2_EXT(obj, notifiee, func, type) notifiee::func##_PNotifier::Create(obj)

#define PCREATE_NOTIFIER_EXT( obj, notifiee, func) notifiee::func##_PNotifier::Create(obj)


#define PCREATE_NOTIFIER2(func, type) P_DISABLE_MSVC_WARNINGS(4355, func##_PNotifier::Create(this))

#define PCREATE_NOTIFIER(func) P_DISABLE_MSVC_WARNINGS(4355, func##_PNotifier::Create(this))


#endif // PTLIB_NOTIFIER_H


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