File: StrongPointer.h

package info (click to toggle)
android-platform-tools 34.0.5-12
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 150,900 kB
  • sloc: cpp: 805,786; java: 293,500; ansic: 128,288; xml: 127,491; python: 41,481; sh: 14,245; javascript: 9,665; cs: 3,846; asm: 2,049; makefile: 1,917; yacc: 440; awk: 368; ruby: 183; sql: 140; perl: 88; lex: 67
file content (361 lines) | stat: -rw-r--r-- 11,962 bytes parent folder | download | duplicates (2)
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
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
/*
 * Copyright (C) 2005 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ANDROID_STRONG_POINTER_H
#define ANDROID_STRONG_POINTER_H

#include <functional>
#include <type_traits>  // for common_type.

// ---------------------------------------------------------------------------
namespace android {

template<typename T> class wp;

// ---------------------------------------------------------------------------

template<typename T>
class sp {
public:
    inline sp() : m_ptr(nullptr) { }

    // The old way of using sp<> was like this. This is bad because it relies
    // on implicit conversion to sp<>, which we would like to remove (if an
    // object is being managed some other way, this is double-ownership). We
    // want to move away from this:
    //
    //     sp<Foo> foo = new Foo(...); // DO NOT DO THIS
    //
    // Instead, prefer to do this:
    //
    //     sp<Foo> foo = sp<Foo>::make(...); // DO THIS
    //
    // Sometimes, in order to use this, when a constructor is marked as private,
    // you may need to add this to your class:
    //
    //     friend class sp<Foo>;
    template <typename... Args>
    static inline sp<T> make(Args&&... args);

    // if nullptr, returns nullptr
    //
    // if a strong pointer is already available, this will retrieve it,
    // otherwise, this will abort
    static inline sp<T> fromExisting(T* other);

    // for more information about this macro and correct RefBase usage, see
    // the comment at the top of utils/RefBase.h
#if defined(ANDROID_UTILS_REF_BASE_DISABLE_IMPLICIT_CONSTRUCTION)
    sp(std::nullptr_t) : sp() {}
#else
    sp(T* other);  // NOLINT(implicit)
    template <typename U>
    sp(U* other);  // NOLINT(implicit)
    sp& operator=(T* other);
    template <typename U>
    sp& operator=(U* other);
#endif

    sp(const sp<T>& other);
    sp(sp<T>&& other) noexcept;

    template<typename U> sp(const sp<U>& other);  // NOLINT(implicit)
    template<typename U> sp(sp<U>&& other);  // NOLINT(implicit)

    // Cast a strong pointer directly from one type to another. Constructors
    // allow changing types, but only if they are pointer-compatible. This does
    // a static_cast internally.
    template <typename U>
    static inline sp<T> cast(const sp<U>& other);

    ~sp();

    // Assignment

    sp& operator = (const sp<T>& other);
    sp& operator=(sp<T>&& other) noexcept;

    template<typename U> sp& operator = (const sp<U>& other);
    template<typename U> sp& operator = (sp<U>&& other);

    //! Special optimization for use by ProcessState (and nobody else).
    void force_set(T* other);

    // Reset

    void clear();

    // Accessors

    inline T&       operator* () const     { return *m_ptr; }
    inline T*       operator-> () const    { return m_ptr;  }
    inline T*       get() const            { return m_ptr; }
    inline explicit operator bool () const { return m_ptr != nullptr; }

    // Punt these to the wp<> implementation.
    template<typename U>
    inline bool operator == (const wp<U>& o) const {
        return o == *this;
    }

    template<typename U>
    inline bool operator != (const wp<U>& o) const {
        return o != *this;
    }

private:
    template<typename Y> friend class sp;
    template<typename Y> friend class wp;
    void set_pointer(T* ptr);
    T* m_ptr;
};

#define COMPARE_STRONG(_op_)                                           \
    template <typename T, typename U>                                  \
    static inline bool operator _op_(const sp<T>& t, const sp<U>& u) { \
        return t.get() _op_ u.get();                                   \
    }                                                                  \
    template <typename T, typename U>                                  \
    static inline bool operator _op_(const T* t, const sp<U>& u) {     \
        return t _op_ u.get();                                         \
    }                                                                  \
    template <typename T, typename U>                                  \
    static inline bool operator _op_(const sp<T>& t, const U* u) {     \
        return t.get() _op_ u;                                         \
    }                                                                  \
    template <typename T>                                              \
    static inline bool operator _op_(const sp<T>& t, std::nullptr_t) { \
        return t.get() _op_ nullptr;                                   \
    }                                                                  \
    template <typename T>                                              \
    static inline bool operator _op_(std::nullptr_t, const sp<T>& t) { \
        return nullptr _op_ t.get();                                   \
    }

template <template <typename C> class comparator, typename T, typename U>
static inline bool _sp_compare_(T* a, U* b) {
    return comparator<typename std::common_type<T*, U*>::type>()(a, b);
}

#define COMPARE_STRONG_FUNCTIONAL(_op_, _compare_)                     \
    template <typename T, typename U>                                  \
    static inline bool operator _op_(const sp<T>& t, const sp<U>& u) { \
        return _sp_compare_<_compare_>(t.get(), u.get());              \
    }                                                                  \
    template <typename T, typename U>                                  \
    static inline bool operator _op_(const T* t, const sp<U>& u) {     \
        return _sp_compare_<_compare_>(t, u.get());                    \
    }                                                                  \
    template <typename T, typename U>                                  \
    static inline bool operator _op_(const sp<T>& t, const U* u) {     \
        return _sp_compare_<_compare_>(t.get(), u);                    \
    }                                                                  \
    template <typename T>                                              \
    static inline bool operator _op_(const sp<T>& t, std::nullptr_t) { \
        return _sp_compare_<_compare_>(t.get(), nullptr);              \
    }                                                                  \
    template <typename T>                                              \
    static inline bool operator _op_(std::nullptr_t, const sp<T>& t) { \
        return _sp_compare_<_compare_>(nullptr, t.get());              \
    }

COMPARE_STRONG(==)
COMPARE_STRONG(!=)
COMPARE_STRONG_FUNCTIONAL(>, std::greater)
COMPARE_STRONG_FUNCTIONAL(<, std::less)
COMPARE_STRONG_FUNCTIONAL(<=, std::less_equal)
COMPARE_STRONG_FUNCTIONAL(>=, std::greater_equal)

#undef COMPARE_STRONG
#undef COMPARE_STRONG_FUNCTIONAL

// For code size reasons, we do not want these inlined or templated.
void sp_report_race();

// ---------------------------------------------------------------------------
// No user serviceable parts below here.

// TODO: Ideally we should find a way to increment the reference count before running the
// constructor, so that generating an sp<> to this in the constructor is no longer dangerous.
template <typename T>
template <typename... Args>
sp<T> sp<T>::make(Args&&... args) {
    T* t = new T(std::forward<Args>(args)...);
    sp<T> result;
    result.m_ptr = t;
    t->incStrong(t);
    return result;
}

template <typename T>
sp<T> sp<T>::fromExisting(T* other) {
    if (other) {
        other->incStrongRequireStrong(other);
        sp<T> result;
        result.m_ptr = other;
        return result;
    }
    return nullptr;
}

#if !defined(ANDROID_UTILS_REF_BASE_DISABLE_IMPLICIT_CONSTRUCTION)
template<typename T>
sp<T>::sp(T* other)
        : m_ptr(other) {
    if (other) {
        other->incStrong(this);
    }
}

template <typename T>
template <typename U>
sp<T>::sp(U* other) : m_ptr(other) {
    if (other) {
        (static_cast<T*>(other))->incStrong(this);
    }
}

template <typename T>
sp<T>& sp<T>::operator=(T* other) {
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    if (other) {
        other->incStrong(this);
    }
    if (oldPtr) oldPtr->decStrong(this);
    if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
    m_ptr = other;
    return *this;
}
#endif

template<typename T>
sp<T>::sp(const sp<T>& other)
        : m_ptr(other.m_ptr) {
    if (m_ptr)
        m_ptr->incStrong(this);
}

template <typename T>
sp<T>::sp(sp<T>&& other) noexcept : m_ptr(other.m_ptr) {
    other.m_ptr = nullptr;
}

template<typename T> template<typename U>
sp<T>::sp(const sp<U>& other)
        : m_ptr(other.m_ptr) {
    if (m_ptr)
        m_ptr->incStrong(this);
}

template<typename T> template<typename U>
sp<T>::sp(sp<U>&& other)
        : m_ptr(other.m_ptr) {
    other.m_ptr = nullptr;
}

template <typename T>
template <typename U>
sp<T> sp<T>::cast(const sp<U>& other) {
    return sp<T>::fromExisting(static_cast<T*>(other.get()));
}

template<typename T>
sp<T>::~sp() {
    if (m_ptr)
        m_ptr->decStrong(this);
}

template<typename T>
sp<T>& sp<T>::operator =(const sp<T>& other) {
    // Force m_ptr to be read twice, to heuristically check for data races.
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    T* otherPtr(other.m_ptr);
    if (otherPtr) otherPtr->incStrong(this);
    if (oldPtr) oldPtr->decStrong(this);
    if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
    m_ptr = otherPtr;
    return *this;
}

template <typename T>
sp<T>& sp<T>::operator=(sp<T>&& other) noexcept {
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    if (oldPtr) oldPtr->decStrong(this);
    if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
    m_ptr = other.m_ptr;
    other.m_ptr = nullptr;
    return *this;
}

template<typename T> template<typename U>
sp<T>& sp<T>::operator =(const sp<U>& other) {
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    T* otherPtr(other.m_ptr);
    if (otherPtr) otherPtr->incStrong(this);
    if (oldPtr) oldPtr->decStrong(this);
    if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
    m_ptr = otherPtr;
    return *this;
}

template<typename T> template<typename U>
sp<T>& sp<T>::operator =(sp<U>&& other) {
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    if (m_ptr) m_ptr->decStrong(this);
    if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
    m_ptr = other.m_ptr;
    other.m_ptr = nullptr;
    return *this;
}

#if !defined(ANDROID_UTILS_REF_BASE_DISABLE_IMPLICIT_CONSTRUCTION)
template<typename T> template<typename U>
sp<T>& sp<T>::operator =(U* other) {
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    if (other) (static_cast<T*>(other))->incStrong(this);
    if (oldPtr) oldPtr->decStrong(this);
    if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
    m_ptr = other;
    return *this;
}
#endif

template<typename T>
void sp<T>::force_set(T* other) {
    other->forceIncStrong(this);
    m_ptr = other;
}

template<typename T>
void sp<T>::clear() {
    T* oldPtr(*const_cast<T* volatile*>(&m_ptr));
    if (oldPtr) {
        oldPtr->decStrong(this);
        if (oldPtr != *const_cast<T* volatile*>(&m_ptr)) sp_report_race();
        m_ptr = nullptr;
    }
}

template<typename T>
void sp<T>::set_pointer(T* ptr) {
    m_ptr = ptr;
}

}  // namespace android

// ---------------------------------------------------------------------------

#endif // ANDROID_STRONG_POINTER_H