forked from Kitware/VTK
-
Notifications
You must be signed in to change notification settings - Fork 0
/
vtkWeakPointer.h
318 lines (277 loc) · 9.99 KB
/
vtkWeakPointer.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
/*=========================================================================
Program: Visualization Toolkit
Module: vtkWeakPointer.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 vtkWeakPointer
* @brief a weak reference to a vtkObject.
*
* A weak reference to a vtkObject, which means that assigning
* a vtkObject to the vtkWeakPointer does not affect the reference count of the
* vtkObject. However, when the vtkObject is destroyed, the vtkWeakPointer gets
* initialized to nullptr, thus avoiding any dangling references.
*
* \code
* vtkTable *table = vtkTable::New();
* vtkWeakPointer<vtkTable> weakTable = table;
* \endcode
*
* Some time later the table may be deleted, but if it is tested for null then
* the weak pointer will not leave a dangling pointer.
*
* \code
* table->Delete();
* if (weakTable)
* {
* // Never executed as the weak table pointer will be null here
* cout << "Number of columns in table: " << weakTable->GetNumberOfColumns()
* << endl;
* }
* \endcode
*/
#ifndef vtkWeakPointer_h
#define vtkWeakPointer_h
#include "vtkWeakPointerBase.h"
#include "vtkMeta.h" // for IsComplete
#include "vtkNew.h" // for vtkNew
#include <type_traits> // for is_base_of
#include <utility> // for std::move
template <class T>
class vtkWeakPointer : public vtkWeakPointerBase
{
// These static asserts only fire when the function calling CheckTypes is
// used. Thus, this smart pointer class may still be used as a member variable
// with a forward declared T, so long as T is defined by the time the calling
// function is used.
template <typename U = T>
static void CheckTypes() noexcept
{
static_assert(vtk::detail::IsComplete<T>::value,
"vtkWeakPointer<T>'s T type has not been defined. Missing "
"include?");
static_assert(vtk::detail::IsComplete<U>::value,
"Cannot store an object with undefined type in "
"vtkWeakPointer. Missing include?");
static_assert(std::is_base_of<T, U>::value,
"Argument type is not compatible with vtkWeakPointer<T>'s "
"T type.");
static_assert(std::is_base_of<vtkObjectBase, T>::value,
"vtkWeakPointer can only be used with subclasses of "
"vtkObjectBase.");
}
public:
/**
* Initialize smart pointer to nullptr.
*/
vtkWeakPointer() noexcept
: vtkWeakPointerBase()
{
}
/**
* Initialize smart pointer with the given smart pointer.
* @{
*/
vtkWeakPointer(const vtkWeakPointer& r)
: vtkWeakPointerBase(r)
{
}
template <class U>
vtkWeakPointer(const vtkWeakPointer<U>& r)
: vtkWeakPointerBase(r)
{
vtkWeakPointer::CheckTypes<U>();
}
/* @} **/
/**
* Move r's object into the new weak pointer, setting r to nullptr.
* @{
*/
vtkWeakPointer(vtkWeakPointer&& r) noexcept
: vtkWeakPointerBase(std::move(r))
{
}
template <class U>
vtkWeakPointer(vtkWeakPointer<U>&& r) noexcept
: vtkWeakPointerBase(std::move(r))
{
vtkWeakPointer::CheckTypes<U>();
}
/* @} **/
/**
* Initialize smart pointer to given object.
* @{
*/
vtkWeakPointer(T* r)
: vtkWeakPointerBase(r)
{
vtkWeakPointer::CheckTypes();
}
template <typename U>
vtkWeakPointer(const vtkNew<U>& r)
: vtkWeakPointerBase(r.Object)
{ // Create a new reference on copy
vtkWeakPointer::CheckTypes<U>();
}
///@}
///@{
/**
* Assign object to reference.
*/
vtkWeakPointer& operator=(const vtkWeakPointer& r)
{
this->vtkWeakPointerBase::operator=(r);
return *this;
}
template <class U>
vtkWeakPointer& operator=(const vtkWeakPointer<U>& r)
{
vtkWeakPointer::CheckTypes<U>();
this->vtkWeakPointerBase::operator=(r);
return *this;
}
///@}
///@{
/**
* Move r's object into this weak pointer, setting r to nullptr.
*/
vtkWeakPointer& operator=(vtkWeakPointer&& r) noexcept
{
this->vtkWeakPointerBase::operator=(std::move(r));
return *this;
}
template <class U>
vtkWeakPointer& operator=(vtkWeakPointer<U>&& r) noexcept
{
vtkWeakPointer::CheckTypes<U>();
this->vtkWeakPointerBase::operator=(std::move(r));
return *this;
}
///@}
///@{
/**
* Assign object to reference.
*/
vtkWeakPointer& operator=(T* r)
{
vtkWeakPointer::CheckTypes();
this->vtkWeakPointerBase::operator=(r);
return *this;
}
template <typename U>
vtkWeakPointer& operator=(const vtkNew<U>& r)
{
vtkWeakPointer::CheckTypes<U>();
this->vtkWeakPointerBase::operator=(r.Object);
return *this;
}
///@}
///@{
/**
* Get the contained pointer.
*/
T* GetPointer() const noexcept { return static_cast<T*>(this->Object); }
T* Get() const noexcept { return static_cast<T*>(this->Object); }
operator T*() const noexcept { return static_cast<T*>(this->Object); }
/**
* Dereference the pointer and return a reference to the contained
* object.
*/
T& operator*() const noexcept { return *static_cast<T*>(this->Object); }
/**
* Provides normal pointer target member access using operator ->.
*/
T* operator->() const noexcept { return static_cast<T*>(this->Object); }
// Work-around for HP and IBM overload resolution bug. Since
// NullPointerOnly is a private type the only pointer value that can
// be passed by user code is a null pointer. This operator will be
// chosen by the compiler when comparing against null explicitly and
// avoid the bogus ambiguous overload error.
#if defined(__HP_aCC) || defined(__IBMCPP__)
#define VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(op) \
bool operator op(NullPointerOnly*) const { return ::operator op(*this, 0); }
private:
class NullPointerOnly
{
};
public:
VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(==)
VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(!=)
VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(<)
VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(<=)
VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(>)
VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND(>=)
#undef VTK_WEAK_POINTER_DEFINE_OPERATOR_WORKAROUND
#endif
protected:
vtkWeakPointer(T* r, const NoReference& n)
: vtkWeakPointerBase(r, n)
{
}
private:
// These are purposely not implemented to prevent callers from
// trying to take references from other smart pointers.
void TakeReference(const vtkWeakPointerBase&) = delete;
static void Take(const vtkWeakPointerBase&) = delete;
};
#define VTK_WEAK_POINTER_DEFINE_OPERATOR(op) \
template <class T, class U> \
inline bool operator op(const vtkWeakPointer<T>& l, const vtkWeakPointer<U>& r) \
{ \
return (l.GetPointer() op r.GetPointer()); \
} \
template <class T, class U> \
inline bool operator op(T* l, const vtkWeakPointer<U>& r) \
{ \
return (l op r.GetPointer()); \
} \
template <class T, class U> \
inline bool operator op(const vtkWeakPointer<T>& l, U* r) \
{ \
return (l.GetPointer() op r); \
} \
template <class T, class U> \
inline bool operator op(const vtkNew<T>& l, const vtkWeakPointer<U>& r) \
{ \
return (l.GetPointer() op r.GetPointer()); \
} \
template <class T, class U> \
inline bool operator op(const vtkWeakPointer<T>& l, const vtkNew<U>& r) \
{ \
return (l.GetPointer() op r.GetPointer); \
}
/**
* Compare smart pointer values.
*/
VTK_WEAK_POINTER_DEFINE_OPERATOR(==)
VTK_WEAK_POINTER_DEFINE_OPERATOR(!=)
VTK_WEAK_POINTER_DEFINE_OPERATOR(<)
VTK_WEAK_POINTER_DEFINE_OPERATOR(<=)
VTK_WEAK_POINTER_DEFINE_OPERATOR(>)
VTK_WEAK_POINTER_DEFINE_OPERATOR(>=)
#undef VTK_WEAK_POINTER_DEFINE_OPERATOR
namespace vtk
{
/// Construct a vtkWeakPointer<T> containing @a obj. @a obj's reference count
/// is not changed.
template <typename T>
vtkWeakPointer<T> TakeWeakPointer(T* obj)
{
return vtkWeakPointer<T>(obj);
}
} // end namespace vtk
/**
* Streaming operator to print smart pointer like regular pointers.
*/
template <class T>
inline ostream& operator<<(ostream& os, const vtkWeakPointer<T>& p)
{
return os << static_cast<const vtkWeakPointerBase&>(p);
}
#endif
// VTK-HeaderTest-Exclude: vtkWeakPointer.h