mlEventSource.h

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/*************************************************************************************
**
** Copyright 2011, MeVis Medical Solutions AG
**
** The user may use this file in accordance with the license agreement provided with
** the Software or, alternatively, in accordance with the terms contained in a
** written agreement between the user and MeVis Medical Solutions AG.
**
** For further information use the contact form at https://www.mevislab.de/contact
**
**************************************************************************************/
 
#ifndef ML_EVENT_SOURCE_H
#define ML_EVENT_SOURCE_H
 
 
#include "mlBase.h"
 
ML_START_NAMESPACE
 
class BaseEvent;
 
typedef void BaseEventCallback(void*, BaseEvent*);
 
//----------------------------------------------------------------------
class ML_UTILS_EXPORT EventSource : public Base
{
public:
  EventSource();
  EventSource(const EventSource& evSource);
  ~EventSource() override;
 
  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 = nullptr);
 
private:
  struct ListenerEntry {
    ListenerEntry() : cb(nullptr), userData(nullptr) {}
    ListenerEntry(BaseEventCallback* aCB, void* aUserData) : cb(aCB), userData(aUserData) {}
    void sendEvent(BaseEvent* event) const { (*cb)(userData, event); }
    bool isValid() const { return (cb != nullptr); }
    bool operator==(const ListenerEntry& b) const { return cb == b.cb && userData == b.userData; }
 
    BaseEventCallback* cb;
    void* userData;
  };
 
  std::vector<ListenerEntry> _eventListeners;
  bool _inEventListenerIteration;
  bool _eventListenersRemovedInIteration;
};
 
//----------------------------------------------------------------------
 
class ML_UTILS_EXPORT BaseEvent
{
public:
  BaseEvent() : _source(nullptr) {}
  virtual ~BaseEvent() {}
 
  EventSource* source() const { return _source; }
 
  ML_ABSTRACT_ROOT_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