vtkMRMLLayerDMObjectEventObserver.h

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/*==============================================================================
 
  Program: 3D Slicer
 
  Copyright (c) Kitware SAS
 
  See COPYRIGHT.txt
  or http://www.slicer.org/copyright/copyright.txt for details.
 
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
 
  This file was originally developed by Thibault Pelletier, Kitware SAS,
  and was partially funded by ANR grants ANR-22-CE45-0034 and ANR-18-RHUS-005.
 
==============================================================================*/
 
#ifndef __vtkMRMLLayerDMObjectEventObserver_h
#define __vtkMRMLLayerDMObjectEventObserver_h
 
// LayerDM includes
#include "vtkSlicerLayerDMModuleMRMLExport.h"
 
// VTK includes
#include <vtkCommand.h>
#include <vtkObject.h>
#include <vtkSmartPointer.h>
#include <vtkWeakPointer.h>
 
// STL includes
#include <functional>
#include <map>
#include <set>
#include <variant>
#include <vector>
 
class vtkCallbackCommand;

class VTK_SLICER_LAYERDM_MODULE_MRML_EXPORT vtkMRMLLayerDMObjectEventObserver : public vtkObject
{
public:
  struct UpdateGuard;
  static vtkMRMLLayerDMObjectEventObserver* New();
  vtkTypeMacro(vtkMRMLLayerDMObjectEventObserver, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  bool UpdateObservation(vtkObject* prevObj, vtkObject* obj, unsigned long event = vtkCommand::ModifiedEvent);
  bool UpdateObservation(vtkObject* prevObj, vtkObject* obj, const std::vector<unsigned long>& events);

  void RemoveObservations(vtkObject* obj);

  void SetUpdateCallback(const std::function<void(vtkObject* node)>& callback);
  void SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId)>& callback);
  void SetUpdateCallback(const std::function<void(vtkObject* node, unsigned long eventId, void* callData)>& callback);

  void ClearCallback();

  bool SetBlocked(bool isBlocked);
  bool IsBlocked() const;

  struct UpdateGuard
  {
    UpdateGuard(vtkMRMLLayerDMObjectEventObserver* obs);
    ~UpdateGuard();
 
  private:
    vtkMRMLLayerDMObjectEventObserver* Observer;
    bool WasBlocked{};
  };
 
protected:
  vtkMRMLLayerDMObjectEventObserver();
  ~vtkMRMLLayerDMObjectEventObserver() override;
 
private:
  void AddObservation(vtkObject* obj, unsigned long event);

  void InvokeCallback(vtkObject* obj, unsigned long eventId, void* callData);

  void OnObjectDeleted(vtkObject* obj);
 
  vtkSmartPointer<vtkCallbackCommand> UpdateCommand;
  std::map<vtkObject*, std::map<unsigned long, unsigned long>> ObservedEventsMap;
  std::set<vtkObject*> DeleteEventObservers;
  std::variant<std::function<void(vtkObject* node)>,
               std::function<void(vtkObject* node, unsigned long eventId)>,
               std::function<void(vtkObject* node, unsigned long eventId, void* callData)>>
    Callback;
  bool Blocked;
};
 
#endif