vtkObject.h

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

  Program:   Visualization Toolkit
  Module:    vtkObject.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm 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 vtkObject_h
#define vtkObject_h

#include "vtkCommonCoreModule.h" // For export macro
#include "vtkObjectBase.h"
#include "vtkSetGet.h"
#include "vtkTimeStamp.h"
#include "vtkWeakPointerBase.h" // needed for vtkWeakPointer

class vtkSubjectHelper;
class vtkCommand;

class VTKCOMMONCORE_EXPORT vtkObject : public vtkObjectBase
{
public:
  vtkBaseTypeMacro(vtkObject, vtkObjectBase);

  static vtkObject* New();

#ifdef _WIN32
  // avoid dll boundary problems
  void* operator new(size_t tSize);
  void operator delete(void* p);
#endif

  virtual void DebugOn();

  virtual void DebugOff();

  bool GetDebug();

  void SetDebug(bool debugFlag);

  static void BreakOnError();

  virtual void Modified();

  virtual vtkMTimeType GetMTime();

  void PrintSelf(ostream& os, vtkIndent indent) override;


  static void SetGlobalWarningDisplay(int val);
  static void GlobalWarningDisplayOn() { vtkObject::SetGlobalWarningDisplay(1); }
  static void GlobalWarningDisplayOff() { vtkObject::SetGlobalWarningDisplay(0); }
  static int GetGlobalWarningDisplay();


  unsigned long AddObserver(unsigned long event, vtkCommand*, float priority = 0.0f);
  unsigned long AddObserver(const char* event, vtkCommand*, float priority = 0.0f);
  vtkCommand* GetCommand(unsigned long tag);
  void RemoveObserver(vtkCommand*);
  void RemoveObservers(unsigned long event, vtkCommand*);
  void RemoveObservers(const char* event, vtkCommand*);
  vtkTypeBool HasObserver(unsigned long event, vtkCommand*);
  vtkTypeBool HasObserver(const char* event, vtkCommand*);

  void RemoveObserver(unsigned long tag);
  void RemoveObservers(unsigned long event);
  void RemoveObservers(const char* event);
  void RemoveAllObservers(); // remove every last one of them
  vtkTypeBool HasObserver(unsigned long event);
  vtkTypeBool HasObserver(const char* event);


  template <class U, class T>
  unsigned long AddObserver(
    unsigned long event, U observer, void (T::*callback)(), float priority = 0.0f)
  {
    vtkClassMemberCallback<T>* callable = new vtkClassMemberCallback<T>(observer, callback);
    // callable is deleted when the observer is cleaned up (look at
    // vtkObjectCommandInternal)
    return this->AddTemplatedObserver(event, callable, priority);
  }
  template <class U, class T>
  unsigned long AddObserver(unsigned long event, U observer,
    void (T::*callback)(vtkObject*, unsigned long, void*), float priority = 0.0f)
  {
    vtkClassMemberCallback<T>* callable = new vtkClassMemberCallback<T>(observer, callback);
    // callable is deleted when the observer is cleaned up (look at
    // vtkObjectCommandInternal)
    return this->AddTemplatedObserver(event, callable, priority);
  }


  template <class U, class T>
  unsigned long AddObserver(unsigned long event, U observer,
    bool (T::*callback)(vtkObject*, unsigned long, void*), float priority = 0.0f)
  {
    vtkClassMemberCallback<T>* callable = new vtkClassMemberCallback<T>(observer, callback);
    // callable is deleted when the observer is cleaned up (look at
    // vtkObjectCommandInternal)
    return this->AddTemplatedObserver(event, callable, priority);
  }


  int InvokeEvent(unsigned long event, void* callData);
  int InvokeEvent(const char* event, void* callData);

  int InvokeEvent(unsigned long event) { return this->InvokeEvent(event, nullptr); }
  int InvokeEvent(const char* event) { return this->InvokeEvent(event, nullptr); }

protected:
  vtkObject();
  ~vtkObject() override;

  // See vtkObjectBase.h.
  void RegisterInternal(vtkObjectBase*, vtkTypeBool check) override;
  void UnRegisterInternal(vtkObjectBase*, vtkTypeBool check) override;

  bool Debug;                      // Enable debug messages
  vtkTimeStamp MTime;              // Keep track of modification time
  vtkSubjectHelper* SubjectHelper; // List of observers on this object


  void InternalGrabFocus(vtkCommand* mouseEvents, vtkCommand* keypressEvents = nullptr);
  void InternalReleaseFocus();

private:
  vtkObject(const vtkObject&) = delete;
  void operator=(const vtkObject&) = delete;

  class vtkClassMemberCallbackBase
  {
  public:

    virtual bool operator()(vtkObject*, unsigned long, void*) = 0;
    virtual ~vtkClassMemberCallbackBase() {}
  };


  template <class T>
  class vtkClassMemberHandlerPointer
  {
  public:
    void operator=(vtkObjectBase* o)
    {
      // The cast is needed in case "o" has multi-inheritance,
      // to offset the pointer to get the vtkObjectBase.
      if ((this->VoidPointer = dynamic_cast<T*>(o)) == nullptr)
      {
        // fallback to just using its vtkObjectBase as-is.
        this->VoidPointer = o;
      }
      this->WeakPointer = o;
      this->UseWeakPointer = true;
    }
    void operator=(void* o)
    {
      this->VoidPointer = o;
      this->WeakPointer = nullptr;
      this->UseWeakPointer = false;
    }
    T* GetPointer()
    {
      if (this->UseWeakPointer && !this->WeakPointer.GetPointer())
      {
        return nullptr;
      }
      return static_cast<T*>(this->VoidPointer);
    }

  private:
    vtkWeakPointerBase WeakPointer;
    void* VoidPointer;
    bool UseWeakPointer;
  };


  template <class T>
  class vtkClassMemberCallback : public vtkClassMemberCallbackBase
  {
    vtkClassMemberHandlerPointer<T> Handler;
    void (T::*Method1)();
    void (T::*Method2)(vtkObject*, unsigned long, void*);
    bool (T::*Method3)(vtkObject*, unsigned long, void*);

  public:
    vtkClassMemberCallback(T* handler, void (T::*method)())
    {
      this->Handler = handler;
      this->Method1 = method;
      this->Method2 = nullptr;
      this->Method3 = nullptr;
    }

    vtkClassMemberCallback(T* handler, void (T::*method)(vtkObject*, unsigned long, void*))
    {
      this->Handler = handler;
      this->Method1 = nullptr;
      this->Method2 = method;
      this->Method3 = nullptr;
    }

    vtkClassMemberCallback(T* handler, bool (T::*method)(vtkObject*, unsigned long, void*))
    {
      this->Handler = handler;
      this->Method1 = nullptr;
      this->Method2 = nullptr;
      this->Method3 = method;
    }
    ~vtkClassMemberCallback() override {}

    // Called when the event is invoked
    bool operator()(vtkObject* caller, unsigned long event, void* calldata) override
    {
      T* handler = this->Handler.GetPointer();
      if (handler)
      {
        if (this->Method1)
        {
          (handler->*this->Method1)();
        }
        else if (this->Method2)
        {
          (handler->*this->Method2)(caller, event, calldata);
        }
        else if (this->Method3)
        {
          return (handler->*this->Method3)(caller, event, calldata);
        }
      }
      return false;
    }
  };


  unsigned long AddTemplatedObserver(
    unsigned long event, vtkClassMemberCallbackBase* callable, float priority);
  // Friend to access AddTemplatedObserver().
  friend class vtkObjectCommandInternal;
};

#endif
// VTK-HeaderTest-Exclude: vtkObject.h