MeVis/Foundation/Sources/MLUtilities/mlEventSource.h

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// **InsertLicense** code
//-------------------------------------------------------------------------

//-------------------------------------------------------------------------
#ifndef __mlEventSource_H
#define __mlEventSource_H

#include "mlBase.h"

ML_START_NAMESPACE

class BaseEvent;

typedef void BaseEventCallback(void*, BaseEvent*);

//----------------------------------------------------------------------
class ML_UTILS_EXPORT EventSource : public Base
{
public:
  EventSource() {}
  virtual ~EventSource();

  void addEventListener(BaseEventCallback* cb, void* userData);

  void removeEventListener(BaseEventCallback* cb, void* userData);
  
  bool hasEventListeners() const;

  ML_ABSTRACT_CLASS_HEADER(EventSource)

protected:
  void sendEvent(BaseEvent* event, void* skipListener = NULL);

private:
  struct ListenerEntry {
    ListenerEntry(BaseEventCallback* aCB, void* aUserData) : cb(aCB), userData(aUserData) {}
    void sendEvent(BaseEvent* event) const { (*cb)(userData, event); }
    bool operator==(const ListenerEntry& b) const { return cb == b.cb && userData == b.userData; }

    BaseEventCallback* cb;
    void* userData;
  };

  std::list<ListenerEntry> _eventListeners;
};

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

class ML_UTILS_EXPORT BaseEvent
{
public:
  BaseEvent() : _source(NULL) {}
  virtual ~BaseEvent() {}
  
  EventSource* source() const { return _source; }
  
  ML_ABSTRACT_CLASS_HEADER(BaseEvent)

private:
  friend class EventSource;

  EventSource* _source;
};

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

class ML_UTILS_EXPORT EventSourceDeletedEvent : public BaseEvent
{
public:
  EventSourceDeletedEvent() {}

  ML_CLASS_HEADER(EventSourceDeletedEvent)
};


ML_END_NAMESPACE


template<typename ToTypePtr>
inline ToTypePtr mlbaseevent_cast(ML_UTILS_NAMESPACE::BaseEvent* from) {
  if (from) {
    if (from->getTypeId()->isDerivedFrom((static_cast<ToTypePtr>(0))->getClassTypeId())) {
      return static_cast<ToTypePtr>(from);
    } else {
      return NULL;
    }
  } else {
    return NULL;
  }
}

template<typename ToTypePtr>
inline ToTypePtr mlbaseevent_cast(const ML_UTILS_NAMESPACE::BaseEvent* from) {
  if (from) {
    if (from->getTypeId()->isDerivedFrom((static_cast<ToTypePtr>(0))->getClassTypeId())) {
      return static_cast<ToTypePtr>(from);
    } else {
      return NULL;
    }
  } else {
    return NULL;
  }
}


#endif // __mlEventSource_H