vtkGarbageCollector.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#ifndef vtkGarbageCollector_h
#define vtkGarbageCollector_h

#include "vtkCommonCoreModule.h"        // For export macro
#include "vtkGarbageCollectorManager.h" // Needed for singleton initialization.
#include "vtkObject.h"

#include <mutex> // For `std::mutex` (cannot be forward-declared)

// This function is a friend of the collector so that it can call the
// internal report method.
VTK_ABI_NAMESPACE_BEGIN
void VTKCOMMONCORE_EXPORT vtkGarbageCollectorReportInternal(
  vtkGarbageCollector*, vtkObjectBase*, void*, const char*);

// This forward ref allows us to define methods with vtkNew.
template <class T>
class vtkNew;

// This allows vtkObjectBase to get at the methods it needs.
class vtkObjectBaseToGarbageCollectorFriendship;

class VTKCOMMONCORE_EXPORT vtkGarbageCollector : public vtkObject
{
public:
  vtkTypeMacro(vtkGarbageCollector, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;
  static vtkGarbageCollector* New();

  static void Collect();

  static void Collect(vtkObjectBase* root);


  static void DeferredCollectionPush();
  static void DeferredCollectionPop();


  static void SetGlobalDebugFlag(bool flag);
  static bool GetGlobalDebugFlag();

protected:
  vtkGarbageCollector();
  ~vtkGarbageCollector() override;

private:
  static vtkTypeBool GiveReference(vtkObjectBase* obj);

  static vtkTypeBool TakeReference(vtkObjectBase* obj);

  // Singleton management functions.
  static void ClassInitialize();
  static void ClassFinalize();

  friend class vtkGarbageCollectorManager;
  friend class vtkObjectBaseToGarbageCollectorFriendship;

  static std::mutex* WeakPtrMutex();

  // Internal report callback and friend function that calls it.
  virtual void Report(vtkObjectBase* obj, void* ptr, const char* desc);
  friend void VTKCOMMONCORE_EXPORT vtkGarbageCollectorReportInternal(
    vtkGarbageCollector*, vtkObjectBase*, void*, const char*);

  vtkGarbageCollector(const vtkGarbageCollector&) = delete;
  void operator=(const vtkGarbageCollector&) = delete;
};

class vtkSmartPointerBase;

void VTKCOMMONCORE_EXPORT vtkGarbageCollectorReport(
  vtkGarbageCollector* collector, vtkSmartPointerBase& ptr, const char* desc);

template <class T>
void vtkGarbageCollectorReport(vtkGarbageCollector* collector, vtkNew<T>& ptr, const char* desc)
{
  vtkGarbageCollectorReportInternal(
    collector, ptr.Object, reinterpret_cast<void*>(&ptr.Object), desc);
}

template <class T>
void vtkGarbageCollectorReport(vtkGarbageCollector* collector, T*& ptr, const char* desc)
{
  vtkGarbageCollectorReportInternal(collector, ptr, reinterpret_cast<void*>(&ptr), desc);
}

VTK_ABI_NAMESPACE_END
#endif