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
|
/*
* Copyright 2022 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_MEMORY_ALWAYS_VALID_POINTER_H_
#define RTC_BASE_MEMORY_ALWAYS_VALID_POINTER_H_
#include <memory>
#include <utility>
#include "rtc_base/checks.h"
namespace webrtc {
// This template allows the instantiation of a pointer to Interface in such a
// way that if it is passed a null pointer, an object of class Default will be
// created, which will be deallocated when the pointer is deleted.
template <typename Interface, typename Default = Interface>
class AlwaysValidPointer {
public:
explicit AlwaysValidPointer(Interface* pointer)
: owned_instance_(pointer ? nullptr : std::make_unique<Default>()),
pointer_(pointer ? pointer : owned_instance_.get()) {
RTC_DCHECK(pointer_);
}
template <typename Arg,
typename std::enable_if<!(std::is_invocable<Arg>::value),
bool>::type = true>
AlwaysValidPointer(Interface* pointer, Arg arg)
: owned_instance_(pointer ? nullptr
: std::make_unique<Default>(std::move(arg))),
pointer_(pointer ? pointer : owned_instance_.get()) {
RTC_DCHECK(pointer_);
}
// Multiple arguments
template <typename Arg1, typename... Args>
AlwaysValidPointer(Interface* pointer, Arg1 arg1, Args... args)
: owned_instance_(pointer
? nullptr
: std::make_unique<Default>(std::move(arg1),
std::move(args...))),
pointer_(pointer ? pointer : owned_instance_.get()) {
RTC_DCHECK(pointer_);
}
// Create a pointer by
// a) using |pointer|, without taking ownership
// b) calling |function| and taking ownership of the result
template <typename Func,
typename std::enable_if<std::is_invocable<Func>::value,
bool>::type = true>
AlwaysValidPointer(Interface* pointer, Func function)
: owned_instance_(pointer ? nullptr : function()),
pointer_(owned_instance_ ? owned_instance_.get() : pointer) {
RTC_DCHECK(pointer_);
}
// Create a pointer by
// a) taking over ownership of |instance|
// b) or fallback to |pointer|, without taking ownership.
// c) or Default.
AlwaysValidPointer(std::unique_ptr<Interface>&& instance, Interface* pointer)
: owned_instance_(
instance
? std::move(instance)
: (pointer == nullptr ? std::make_unique<Default>() : nullptr)),
pointer_(owned_instance_ ? owned_instance_.get() : pointer) {
RTC_DCHECK(pointer_);
}
// Create a pointer by
// a) taking over ownership of |instance|
// b) or fallback to |pointer|, without taking ownership.
// c) or Default (with forwarded args).
template <typename... Args>
AlwaysValidPointer(std::unique_ptr<Interface>&& instance,
Interface* pointer,
Args... args)
: owned_instance_(
instance ? std::move(instance)
: (pointer == nullptr
? std::make_unique<Default>(std::move(args...))
: nullptr)),
pointer_(owned_instance_ ? owned_instance_.get() : pointer) {
RTC_DCHECK(pointer_);
}
Interface* get() { return pointer_; }
Interface* operator->() { return pointer_; }
Interface& operator*() { return *pointer_; }
Interface* get() const { return pointer_; }
Interface* operator->() const { return pointer_; }
Interface& operator*() const { return *pointer_; }
private:
const std::unique_ptr<Interface> owned_instance_;
Interface* const pointer_;
};
// This class is similar to AlwaysValidPointer, but it does not create
// a default object and crashes if none of the input pointers are non-null.
template <typename Interface>
class AlwaysValidPointerNoDefault {
public:
explicit AlwaysValidPointerNoDefault(Interface* pointer) : pointer_(pointer) {
RTC_CHECK(pointer_);
}
// Create a pointer by
// a) taking over ownership of |instance|
// b) or fallback to |pointer|, without taking ownership.
// At least one of the arguments must be non-null.
explicit AlwaysValidPointerNoDefault(std::unique_ptr<Interface> instance,
Interface* pointer = nullptr)
: owned_instance_(std::move(instance)),
pointer_(owned_instance_ ? owned_instance_.get() : pointer) {
RTC_CHECK(pointer_);
}
Interface* get() { return pointer_; }
Interface* operator->() { return pointer_; }
Interface& operator*() { return *pointer_; }
Interface* get() const { return pointer_; }
Interface* operator->() const { return pointer_; }
Interface& operator*() const { return *pointer_; }
private:
const std::unique_ptr<Interface> owned_instance_;
Interface* const pointer_;
};
template <typename T, typename U, typename V, typename W>
bool operator==(const AlwaysValidPointer<T, U>& a,
const AlwaysValidPointer<V, W>& b) {
return a.get() == b.get();
}
template <typename T, typename U, typename V, typename W>
bool operator!=(const AlwaysValidPointer<T, U>& a,
const AlwaysValidPointer<V, W>& b) {
return !(a == b);
}
template <typename T, typename U>
bool operator==(const AlwaysValidPointer<T, U>& a, std::nullptr_t) {
return a.get() == nullptr;
}
template <typename T, typename U>
bool operator!=(const AlwaysValidPointer<T, U>& a, std::nullptr_t) {
return !(a == nullptr);
}
template <typename T, typename U>
bool operator==(std::nullptr_t, const AlwaysValidPointer<T, U>& a) {
return a.get() == nullptr;
}
template <typename T, typename U>
bool operator!=(std::nullptr_t, const AlwaysValidPointer<T, U>& a) {
return !(a == nullptr);
}
template <typename T, typename U>
bool operator==(const AlwaysValidPointerNoDefault<T>& a,
const AlwaysValidPointerNoDefault<U>& b) {
return a.get() == b.get();
}
template <typename T, typename U>
bool operator!=(const AlwaysValidPointerNoDefault<T>& a,
const AlwaysValidPointerNoDefault<U>& b) {
return !(a == b);
}
template <typename T>
bool operator==(const AlwaysValidPointerNoDefault<T>& a, std::nullptr_t) {
return a.get() == nullptr;
}
template <typename T>
bool operator!=(const AlwaysValidPointerNoDefault<T>& a, std::nullptr_t) {
return !(a == nullptr);
}
template <typename T>
bool operator==(std::nullptr_t, const AlwaysValidPointerNoDefault<T>& a) {
return a.get() == nullptr;
}
template <typename T>
bool operator!=(std::nullptr_t, const AlwaysValidPointerNoDefault<T>& a) {
return !(a == nullptr);
}
// Comparison with raw pointer.
template <typename T, typename U, typename V>
bool operator==(const AlwaysValidPointer<T, U>& a, const V* b) {
return a.get() == b;
}
template <typename T, typename U, typename V>
bool operator!=(const AlwaysValidPointer<T, U>& a, const V* b) {
return !(a == b);
}
template <typename T, typename U, typename V>
bool operator==(const T* a, const AlwaysValidPointer<U, V>& b) {
return a == b.get();
}
template <typename T, typename U, typename V>
bool operator!=(const T* a, const AlwaysValidPointer<U, V>& b) {
return !(a == b);
}
template <typename T, typename U>
bool operator==(const AlwaysValidPointerNoDefault<T>& a, const U* b) {
return a.get() == b;
}
template <typename T, typename U>
bool operator!=(const AlwaysValidPointerNoDefault<T>& a, const U* b) {
return !(a == b);
}
template <typename T, typename U>
bool operator==(const T* a, const AlwaysValidPointerNoDefault<U>& b) {
return a == b.get();
}
template <typename T, typename U>
bool operator!=(const T* a, const AlwaysValidPointerNoDefault<U>& b) {
return !(a == b);
}
} // namespace webrtc
#endif // RTC_BASE_MEMORY_ALWAYS_VALID_POINTER_H_
|
