VTK  9.1.0
vtkNew.h
Go to the documentation of this file.
1/*=========================================================================
2
3 Program: Visualization Toolkit
4 Module: vtkNew.h
5
6 Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
7 All rights reserved.
8 See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
9
10 This software is distributed WITHOUT ANY WARRANTY; without even
11 the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
12 PURPOSE. See the above copyright notice for more information.
13
14=========================================================================*/
44#ifndef vtkNew_h
45#define vtkNew_h
46
47#include "vtkIOStream.h"
48#include "vtkMeta.h" // for IsComplete
49
50#include <type_traits> // for is_base_of
51
52class vtkObjectBase;
53
54template <class T>
55class vtkNew
56{
57 // Allow other smart pointers friend access:
58 template <typename U>
59 friend class vtkNew;
60 template <typename U>
61 friend class vtkSmartPointer;
62 template <typename U>
63 friend class vtkWeakPointer;
64
65 // These static asserts only fire when the function calling CheckTypes is
66 // used. Thus, this smart pointer class may still be used as a member variable
67 // with a forward declared T, so long as T is defined by the time the calling
68 // function is used.
69 template <typename U = T>
70 static void CheckTypes() noexcept
71 {
73 "vtkNew<T>'s T type has not been defined. Missing include?");
75 "Cannot store an object with undefined type in "
76 "vtkNew. Missing include?");
77 static_assert(std::is_base_of<T, U>::value,
78 "Argument type is not compatible with vtkNew<T>'s "
79 "T type.");
81 "vtkNew can only be used with subclasses of vtkObjectBase.");
82 }
83
84public:
89 : Object(T::New())
90 {
91 vtkNew::CheckTypes();
92 }
93
99 vtkNew(vtkNew&& o) noexcept
100 : Object(o.Object)
101 {
102 o.Object = nullptr;
103 }
104
105 template <typename U>
106 vtkNew(vtkNew<U>&& o) noexcept
107 : Object(o.Object)
108 {
109 vtkNew::CheckTypes<U>();
110
111 o.Object = nullptr;
112 }
114
116
119 ~vtkNew() { this->Reset(); }
120
121 void Reset()
122 {
123 T* obj = this->Object;
124 if (obj)
125 {
126 this->Object = nullptr;
127 obj->Delete();
128 }
129 }
131
136 T* operator->() const noexcept { return this->Object; }
137
139
145 T* GetPointer() const noexcept { return this->Object; }
146 T* Get() const noexcept { return this->Object; }
147 operator T*() const noexcept { return static_cast<T*>(this->Object); }
149
155 T& operator*() const noexcept { return *static_cast<T*>(this->Object); }
156
157private:
158 vtkNew(vtkNew<T> const&) = delete;
159 void operator=(vtkNew<T> const&) = delete;
160 T* Object;
161};
162
163#endif
164// VTK-HeaderTest-Exclude: vtkNew.h
Allocate and hold a VTK object.
Definition: vtkNew.h:56
void Reset()
Deletes reference to instance of T.
Definition: vtkNew.h:121
T * Get() const noexcept
Get a raw pointer to the contained object.
Definition: vtkNew.h:146
friend class vtkNew
Definition: vtkNew.h:59
vtkNew()
Create a new T on construction.
Definition: vtkNew.h:88
T * operator->() const noexcept
Enable pointer-like dereference syntax.
Definition: vtkNew.h:136
vtkNew(vtkNew &&o) noexcept
Move the object into the constructed vtkNew wrapper, stealing its reference.
Definition: vtkNew.h:99
~vtkNew()
Deletes reference to instance of T.
Definition: vtkNew.h:119
vtkNew(vtkNew< U > &&o) noexcept
Move the object into the constructed vtkNew wrapper, stealing its reference.
Definition: vtkNew.h:106
T * GetPointer() const noexcept
Get a raw pointer to the contained object.
Definition: vtkNew.h:145
T & operator*() const noexcept
Dereference the pointer and return a reference to the contained object.
Definition: vtkNew.h:155
abstract base class for most VTK objects
Definition: vtkObjectBase.h:70
virtual void Delete()
Delete a VTK object.
Hold a reference to a vtkObjectBase instance.
vtkObjectBase * Object
a weak reference to a vtkObject.
vtkWeakPointer & operator=(const vtkWeakPointer &r)
Assign object to reference.
@ value
Definition: vtkX3D.h:226
This file contains a variety of metaprogramming constructs for working with vtk types.