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nmWTAI-Platform/3rd/VTK7.1/include/vtkNew.h

134 lines
3.2 KiB
C++

/*=========================================================================
Program: Visualization Toolkit
Module: vtkNew.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.
=========================================================================*/
/**
* @class vtkNew
* @brief Allocate and hold a VTK object.
*
* vtkNew is a class template that on construction allocates and
* initializes an instance of its template argument using T::New().
* It assumes ownership of one reference during its lifetime, and calls
* T->Delete() on destruction.
*
* Automatic casting is intentionally unavailable, calling GetPointer() will
* return a raw pointer. Users of this method should ensure that they do not
* return this pointer if the vtkNew will go out of scope without
* incrementing its reference count using vtkSmartPointer or similar.
*
* \code
* vtkNew<vtkClass> a;
* a->SomeMethod();
*
* vtkSmartPointer<vtkClass> b = a.GetPointer();
* b->SomeOtherMethod();
* \endcode
*
* It should be noted that vtkNew is not a drop in replacement for
* vtkSmartPointer as it is not implicitly cast to a pointer in functions
* requiring a pointer. The GetPointer() method must be used, for example,
*
* \code
* vtkNew<vtkRenderer> ren;
* vtkNew<vtkRenderWindow> renWin;
* renWin->AddRenderer(ren.GetPointer());
* vtkNew<vtkRenderWindowInteractor> iren;
* iren->SetRenderWindow(renWin.GetPointer());
* \endcode
*
* @sa
* vtkSmartPointer vtkWeakPointer
*/
#ifndef vtkNew_h
#define vtkNew_h
#include "vtkIOStream.h"
class vtkObjectBase;
template <class T>
class vtkNew
{
/**
* Compile time checking that the class is derived from vtkObjectBase.
*/
void CheckObjectBase(vtkObjectBase*) {}
public:
/**
* Create a new T on construction.
*/
vtkNew() : Object(T::New())
{
this->CheckObjectBase(this->Object);
}
//@{
/**
* Deletes reference to instance of T on destruction.
*/
~vtkNew()
{
T* obj = this->Object;
if (obj)
{
this->Object = 0;
obj->Delete();
}
}
//@}
/**
* Enable pointer-like dereference syntax. Returns a pointer to the contained
* object.
*/
T* operator->() const
{
return this->Object;
}
//@{
/**
* Get a raw pointer to the contained object. When using this function be
* careful that the reference count does not drop to 0 when using the pointer
* returned. This will happen when the vtkNew object goes out of
* scope for example.
*/
T* GetPointer() const
{
return this->Object;
}
T* Get() const
{
return this->Object;
}
//@}
private:
vtkNew(vtkNew<T> const&) VTK_DELETE_FUNCTION;
void operator=(vtkNew<T> const&) VTK_DELETE_FUNCTION;
T* Object;
};
/**
* Streaming operator to print vtkNew like regular pointers.
*/
template <class T>
inline ostream& operator << (ostream& os, const vtkNew<T>& p)
{
return os << p.GetPointer();
}
#endif
// VTK-HeaderTest-Exclude: vtkNew.h