vtkUndoElement.h

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/*=========================================================================

  Program:   ParaView
  Module:    vtkUndoElement.h

  Copyright (c) Kitware, Inc.
  All rights reserved.
  See Copyright.txt or http://www.paraview.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#ifndef vtkUndoElement_h
#define vtkUndoElement_h

#include "vtkObject.h"
#include "vtkPVVTKExtensionsCoreModule.h" // needed for export macro
class vtkCollection;

class VTKPVVTKEXTENSIONSCORE_EXPORT vtkUndoElement : public vtkObject
{
public:
  vtkTypeMacro(vtkUndoElement, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  virtual int Undo() = 0;

  virtual int Redo() = 0;


  vtkGetMacro(Mergeable, bool);

  virtual bool Merge(vtkUndoElement* vtkNotUsed(new_element)) { return false; }

  // Set the working context if run inside a UndoSet context, so object
  // that are cross referenced can leave long enough to be associated
  // to another object. Otherwise the undo of a Delete will create the object
  // again but as no-one is holding a reference to that newly created object
  // it will be automatically deleted. Therefore, we provide a collection
  // that will hold a reference during an undoset so the object has a chance
  // to be attached to the ProxyManager or any other object.
  virtual void SetUndoSetWorkingContext(vtkCollection* workCTX)
  {
    this->UndoSetWorkingContext = workCTX;
  }

protected:
  vtkUndoElement();
  ~vtkUndoElement() override;


  bool Mergeable;
  vtkSetMacro(Mergeable, bool);
  vtkCollection* UndoSetWorkingContext;

private:
  vtkUndoElement(const vtkUndoElement&) = delete;
  void operator=(const vtkUndoElement&) = delete;
};

#endif