qsharedpointer.cpp

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40-
41#include "qsharedpointer.h"-
42-
43// to be sure we aren't causing a namespace clash:-
44#include "qshareddata.h"-
45-
46/*!-
47 \class QSharedPointer-
48 \inmodule QtCore-
49 \brief The QSharedPointer class holds a strong reference to a shared pointer-
50 \since 4.5-
51-
52 \reentrant-
53-
54 The QSharedPointer is an automatic, shared pointer in C++. It-
55 behaves exactly like a normal pointer for normal purposes,-
56 including respect for constness.-
57-
58 QSharedPointer will delete the pointer it is holding when it goes-
59 out of scope, provided no other QSharedPointer objects are-
60 referencing it.-
61-
62 A QSharedPointer object can be created from a normal pointer,-
63 another QSharedPointer object or by promoting a-
64 QWeakPointer object to a strong reference.-
65-
66 \section1 Thread-Safety-
67-
68 QSharedPointer and QWeakPointer are thread-safe and operate-
69 atomically on the pointer value. Different threads can also access-
70 the QSharedPointer or QWeakPointer pointing to the same object at-
71 the same time without need for locking mechanisms.-
72-
73 It should be noted that, while the pointer value can be accessed-
74 in this manner, QSharedPointer and QWeakPointer provide no-
75 guarantee about the object being pointed to. Thread-safety and-
76 reentrancy rules for that object still apply.-
77-
78 \section1 Other Pointer Classes-
79-
80 Qt also provides two other pointer wrapper classes: QPointer and-
81 QSharedDataPointer. They are incompatible with one another, since-
82 each has its very different use case.-
83-
84 QSharedPointer holds a shared pointer by means of an external-
85 reference count (i.e., a reference counter placed outside the-
86 object). Like its name indicates, the pointer value is shared-
87 among all instances of QSharedPointer and QWeakPointer. The-
88 contents of the object pointed to by the pointer should not be-
89 considered shared, however: there is only one object. For that-
90 reason, QSharedPointer does not provide a way to detach or make-
91 copies of the pointed object.-
92-
93 QSharedDataPointer, on the other hand, holds a pointer to shared-
94 data (i.e., a class derived from QSharedData). It does so by means-
95 of an internal reference count, placed in the QSharedData base-
96 class. This class can, therefore, detach based on the type of-
97 access made to the data being guarded: if it's a non-const access,-
98 it creates a copy atomically for the operation to complete.-
99-
100 QExplicitlySharedDataPointer is a variant of QSharedDataPointer, except-
101 that it only detaches if QExplicitlySharedDataPointer::detach() is-
102 explicitly called (hence the name).-
103-
104 QScopedPointer simply holds a pointer to a heap allocated object and-
105 deletes it in its destructor. This class is useful when an object needs to-
106 be heap allocated and deleted, but no more. QScopedPointer is lightweight,-
107 it makes no use of additional structure or reference counting.-
108-
109 Finally, QPointer holds a pointer to a QObject-derived object, but it-
110 does so weakly. QWeakPointer has the same functionality, but its use for-
111 that function is deprecated.-
112-
113 \section1 Optional Pointer Tracking-
114-
115 A feature of QSharedPointer that can be enabled at compile-time for-
116 debugging purposes is a pointer tracking mechanism. When enabled,-
117 QSharedPointer registers in a global set all the pointers that it tracks.-
118 This allows one to catch mistakes like assigning the same pointer to two-
119 QSharedPointer objects.-
120-
121 This function is enabled by defining the \tt{QT_SHAREDPOINTER_TRACK_POINTERS}-
122 macro before including the QSharedPointer header.-
123-
124 It is safe to use this feature even with code compiled without the-
125 feature. QSharedPointer will ensure that the pointer is removed from the-
126 tracker even from code compiled without pointer tracking.-
127-
128 Note, however, that the pointer tracking feature has limitations on-
129 multiple- or virtual-inheritance (that is, in cases where two different-
130 pointer addresses can refer to the same object). In that case, if a-
131 pointer is cast to a different type and its value changes,-
132 QSharedPointer's pointer tracking mechanism may fail to detect that the-
133 object being tracked is the same.-
134-
135 \omit-
136 \section1 QSharedPointer internals-
137-
138 QSharedPointer has two "private" members: the pointer itself being tracked-
139 and a d-pointer. Those members are private to the class, but QSharedPointer-
140 is friends with QWeakPointer and other QSharedPointer with different-
141 template arguments. (On some compilers, template friends are not supported,-
142 so the members are technically public)-
143-
144 The reason for keeping the pointer value itself outside the d-pointer is-
145 because of multiple inheritance needs. If you have two QSharedPointer-
146 objects of different pointer types, but pointing to the same object in-
147 memory, it could happen that the pointer values are different. The \tt-
148 differentPointers autotest exemplifies this problem. The same thing could-
149 happen in the case of virtual inheritance: a pointer of class matching-
150 the virtual base has different address compared to the pointer of the-
151 complete object. See the \tt virtualBaseDifferentPointers autotest for-
152 this problem.-
153-
154 The d pointer is a pointer to QtSharedPointer::ExternalRefCountData, but it-
155 always points to one of the two classes derived from ExternalRefCountData.-
156-
157 \section2 d-pointer-
158 \section3 QtSharedPointer::ExternalRefCountData-
159-
160 It is basically a reference-counted reference-counter plus a pointer to the-
161 function to be used to delete the pointer. It has three members: \tt-
162 strongref, \tt weakref, and \tt destroyer. The strong reference counter is-
163 controlling the lifetime of the object tracked by QSharedPointer. A-
164 positive value indicates that the object is alive. It's also the number of-
165 QSharedObject instances that are attached to this Data.-
166-
167 When the strong reference count decreases to zero, the object is deleted-
168 (see below for information on custom deleters). The strong reference count-
169 can also exceptionally be -1, indicating that there are no QSharedPointers-
170 attached to an object, which is tracked too. The only case where this is-
171 possible is that of QWeakPointers and QPointers tracking a QObject. Note-
172 that QWeakPointers tracking a QObject is a deprecated feature as of Qt 5.0,-
173 kept only for compatibility with Qt 4.x.-
174-
175 The weak reference count controls the lifetime of the d-pointer itself.-
176 It can be thought of as an internal/intrusive reference count for-
177 ExternalRefCountData itself. This count is equal to the number of-
178 QSharedPointers and QWeakPointers that are tracking this object. In case-
179 the object is a QObject being tracked by QPointer, this number is increased-
180 by 1, since QObjectPrivate tracks it too.-
181-
182 The third member is a pointer to the function that is used to delete the-
183 pointer being tracked. That happens when the destroy() function is called.-
184-
185 The size of this class is the size of the two atomic ints plus the size of-
186 a pointer. On 32-bit architectures, that's 12 bytes, whereas on 64-bit ones-
187 it's 16 bytes. There is no padding.-
188-
189 \section3 QtSharedPointer::ExternalRefCountWithCustomDeleter-
190-
191 This class derives from ExternalRefCountData and is a template class. As-
192 template parameters, it has the type of the pointer being tracked (\tt T)-
193 and a \tt Deleter, which is anything. It adds two fields to its parent-
194 class, matching those template parameters: a member of type \tt Deleter and-
195 a member of type \tt T*. Those members are actually inside a template-
196 struct of type CustomDeleter, which is partially-specialized for normal-
197 deletion. See below for more details on that.-
198-
199 The purpose of this class is to store the pointer to be deleted and the-
200 deleter code along with the d-pointer. This allows the last strong-
201 reference to call any arbitrary function that disposes of the object. For-
202 example, this allows calling QObject::deleteLater() on a given object.-
203 The pointer to the object is kept here because it needs to match the actual-
204 deleter function's parameters, regardless of what template argument the-
205 last QSharedPointer instance had.-
206-
207 This class is never instantiated directly: the constructors and-
208 destructor are private and, in C++11, deleted. Only the create() function-
209 may be called to return an object of this type. See below for construction-
210 details.-
211-
212 The size of this class depends on the size of \tt Deleter. If it's an empty-
213 functor (i.e., no members), ABIs generally assign it the size of 1. But-
214 given that it's followed by a pointer, padding bytes may be inserted so-
215 that the alignment of the class and of the pointer are correct. In that-
216 case, the size of this class is 12+4+4 = 20 bytes on 32-bit architectures,-
217 or 16+8+8 = 40 bytes on 64-bit architectures. If \tt Deleter is a function-
218 pointer, the size should be the same as the empty structure case. If \tt-
219 Deleter is a pointer to a member function (PMF), the size will be bigger-
220 and will depend on the ABI. For architectures using the Itanium C++ ABI, a-
221 PMF is twice the size of a normal pointer. In that case, the size of this-
222 structure will be 12+8+4 = 24 bytes on 32-bit architectures, 16+16+8 = 40-
223 bytes on 64-bit ones.-
224-
225 If the deleter was not specified when creating the QSharedPointer object-
226 (i.e., if a standard \tt delete call is expected), then there's an-
227 optimization that avoids the need to store another function pointer in-
228 ExternalRefCountWithCustomDeleter. Instead, a template specialization makes-
229 a direct delete call. The size of the structure, in this case, is 12+4 = 16-
230 bytes on 32-bit architectures, 16+8 = 24 bytes on 64-bit ones.-
231-
232 \section3 QtSharedPointer::ExternalRefCountWithContiguousData-
233-
234 This class also derives from ExternalRefCountData and it is-
235 also a template class. The template parameter is the type \tt T of the-
236 class which QSharedPointer tracks. It adds only one member to its parent,-
237 which is of type \tt T (the actual type, not a pointer to it).-
238-
239 The purpose of this class is to lay the \tt T object out next to the-
240 reference counts, saving one memory allocation per shared pointer. This-
241 is particularly interesting for small \tt T or for the cases when there-
242 are few if any QWeakPointer tracking the object. This class exists to-
243 implement the QSharedPointer::create() call.-
244-
245 Like ExternalRefCountWithCustomDeleter, this class is never instantiated-
246 directly. This class also provides a create() member that returns the-
247 pointer, and hides its constructors and destructor. With C++11, they're-
248 deleted.-
249-
250 The size of this class depends on the size of \tt T.-
251-
252 \section3 Instantiating ExternalRefCountWithCustomDeleter and ExternalRefCountWithContiguousData-
253-
254 Like explained above, these classes have private constructors. Moreover,-
255 they are not defined anywhere, so trying to call \tt{new ClassType} would-
256 result in a compilation or linker error. Instead, these classes must be-
257 constructed via their create() methods.-
258-
259 Instead of instantiating the class by the normal way, the create() method-
260 calls \tt{operator new} directly with the size of the class, then calls-
261 the parent class's constructor only (that is, ExternalRefCountData's constructor).-
262 This ensures that the inherited members are initialised properly.-
263-
264 After initialising the base class, the-
265 ExternalRefCountWithCustomDeleter::create() function initialises the new-
266 members directly, by using the placement \tt{operator new}. In the case-
267 of the ExternalRefCountWithContiguousData::create() function, the address-
268 to the still-uninitialised \tt T member is saved for the callee to use.-
269 The member is only initialised in QSharedPointer::create(), so that we-
270 avoid having many variants of the internal functions according to the-
271 arguments in use for calling the constructor.-
272-
273 When initialising the parent class, the create() functions pass the-
274 address of the static deleter() member function. That is, when the-
275 destroy() function is called by QSharedPointer, the deleter() functions-
276 are called instead. These functions static_cast the ExternalRefCountData*-
277 parameter to their own type and execute their deletion: for the-
278 ExternalRefCountWithCustomDeleter::deleter() case, it runs the user's-
279 custom deleter, then destroys the deleter; for-
280 ExternalRefCountWithContiguousData::deleter, it simply calls the \tt T-
281 destructor directly.-
282-
283 Only one non-inline function is required per template, which is-
284 the deleter() static member. All the other functions can be inlined.-
285 What's more, the address of deleter() is calculated only in code, which-
286 can be resolved at link-time if the linker can determine that the-
287 function lies in the current application or library module (since these-
288 classes are not exported, that is the case for Windows or for builds with-
289 \tt{-fvisibility=hidden}).-
290-
291 \section3 Modifications due to pointer-tracking-
292-
293 To ensure that pointers created with pointer-tracking enabled get-
294 un-tracked when destroyed, even if destroyed by code compiled without the-
295 feature, QSharedPointer modifies slightly the instructions of the-
296 previous sections.-
297-
298 When ExternalRefCountWithCustomDeleter or-
299 ExternalRefCountWithContiguousData are used, their create() functions-
300 will set the ExternalRefCountData::destroyer function-
301 pointer to safetyCheckDeleter() instead. These static member functions-
302 simply call internalSafetyCheckRemove() before passing control to the-
303 normal deleter() function.-
304-
305 If neither custom deleter nor QSharedPointer::create() are used, then-
306 QSharedPointer uses a custom deleter of its own: the normalDeleter()-
307 function, which simply calls \tt delete. By using a custom deleter, the-
308 safetyCheckDeleter() procedure described above kicks in.-
309-
310 \endomit-
311-
312 \sa QSharedDataPointer, QWeakPointer, QScopedPointer-
313*/-
314-
315/*!-
316 \class QWeakPointer-
317 \inmodule QtCore-
318 \brief The QWeakPointer class holds a weak reference to a shared pointer-
319 \since 4.5-
320 \reentrant-
321-
322 The QWeakPointer is an automatic weak reference to a-
323 pointer in C++. It cannot be used to dereference the pointer-
324 directly, but it can be used to verify if the pointer has been-
325 deleted or not in another context.-
326-
327 QWeakPointer objects can only be created by assignment from a-
328 QSharedPointer.-
329-
330 It's important to note that QWeakPointer provides no automatic casting-
331 operators to prevent mistakes from happening. Even though QWeakPointer-
332 tracks a pointer, it should not be considered a pointer itself, since it-
333 doesn't guarantee that the pointed object remains valid.-
334-
335 Therefore, to access the pointer that QWeakPointer is tracking, you must-
336 first promote it to QSharedPointer and verify if the resulting object is-
337 null or not. QSharedPointer guarantees that the object isn't deleted, so-
338 if you obtain a non-null object, you may use the pointer. See-
339 QWeakPointer::toStrongRef() for an example.-
340-
341 QWeakPointer also provides the QWeakPointer::data() method that returns-
342 the tracked pointer without ensuring that it remains valid. This function-
343 is provided if you can guarantee by external means that the object will-
344 not get deleted (or if you only need the pointer value) and the cost of-
345 creating a QSharedPointer using toStrongRef() is too high.-
346-
347 \omit-
348 \section1 QWeakPointer internals-
349-
350 QWeakPointer shares most of its internal functionality with-
351 \l{QSharedPointer#qsharedpointer-internals}{QSharedPointer}, so see that-
352 class's internal documentation for more information.-
353-
354 QWeakPointer requires an external reference counter in order to operate.-
355 Therefore, it is incompatible by design with \l QSharedData-derived-
356 classes.-
357-
358 It has a special QObject constructor, which works by calling-
359 QtSharedPointer::ExternalRefCountData::getAndRef, which retrieves the-
360 d-pointer from QObjectPrivate. If one isn't set yet, that function-
361 creates the d-pointer and atomically sets it.-
362-
363 If getAndRef needs to create a d-pointer, it sets the strongref to -1,-
364 indicating that the QObject is not shared: QWeakPointer is used only to-
365 determine whether the QObject has been deleted. In that case, it cannot-
366 be upgraded to QSharedPointer (see the previous section).-
367-
368 \endomit-
369-
370 \sa QSharedPointer, QScopedPointer-
371*/-
372-
373/*!-
374 \class QEnableSharedFromThis-
375 \inmodule QtCore-
376 \brief A base class that allows obtaining a QSharedPointer for an object already managed by a shared pointer-
377 \since 5.4-
378-
379 You can inherit this class when you need to create a QSharedPointer-
380 from any instance of a class; for instance, from within the-
381 object itself. The key point is that the technique of-
382 just returning QSharedPointer<T>(this) can not be used, because-
383 this winds up creating multiple distinct QSharedPointer objects-
384 with separate reference counts. For this reason you must never-
385 create more than one QSharedPointer from the same raw pointer.-
386-
387 QEnableSharedFromThis defines two member functions called-
388 sharedFromThis() that return a QSharedPointer<T> and-
389 QSharedPointer<const T>, depending on constness, to \c this:-
390-
391 \code-
392 class Y: public QEnableSharedFromThis<Y>-
393 {-
394 public:-
395 QSharedPointer<Y> f()-
396 {-
397 return sharedFromThis();-
398 }-
399 };-
400-
401 int main()-
402 {-
403 QSharedPointer<Y> p(new Y());-
404 QSharedPointer<Y> y = p->f();-
405 Q_ASSERT(p == y); // p and q must share ownership-
406 }-
407 \endcode-
408-
409 It is also possible to get a shared pointer from an object outside of-
410 the class itself. This is especially useful in code that provides an-
411 interface to scripts, where it is currently not possible to use shared-
412 pointers. For example:-
413-
414 \code-
415 class ScriptInterface : public QObject-
416 {-
417 Q_OBJECT-
418-
419 // ...-
420-
421 public slots:-
422 void slotCalledByScript(Y *managedBySharedPointer)-
423 {-
424 QSharedPointer<Y> yPtr = managedBySharedPointer->sharedFromThis();-
425 // Some other code unrelated to scripts that expects a QSharedPointer<Y> ...-
426 }-
427 };-
428 \endcode-
429*/-
430-
431/*!-
432 \fn QSharedPointer::QSharedPointer()-
433-
434 Creates a QSharedPointer that points to null (0).-
435*/-
436-
437/*!-
438 \fn QSharedPointer::~QSharedPointer()-
439-
440 Destroys this QSharedPointer object. If it is the last reference to-
441 the pointer stored, this will delete the pointer as well.-
442*/-
443-
444/*!-
445 \fn QSharedPointer::QSharedPointer(T *ptr)-
446-
447 Creates a QSharedPointer that points to \a ptr. The pointer \a ptr-
448 becomes managed by this QSharedPointer and must not be passed to-
449 another QSharedPointer object or deleted outside this object.-
450*/-
451-
452/*!-
453 \fn QSharedPointer::QSharedPointer(T *ptr, Deleter deleter)-
454-
455 Creates a QSharedPointer that points to \a ptr. The pointer \a ptr-
456 becomes managed by this QSharedPointer and must not be passed to-
457 another QSharedPointer object or deleted outside this object.-
458-
459 The \a deleter parameter specifies the custom deleter for this-
460 object. The custom deleter is called, instead of the operator delete(),-
461 when the strong reference count drops to 0. This is useful,-
462 for instance, for calling \l {QObject::}{deleteLater()} on a QObject instead:-
463-
464 \code-
465 static void doDeleteLater(MyObject *obj)-
466 {-
467 obj->deleteLater();-
468 }-
469-
470 void otherFunction()-
471 {-
472 QSharedPointer<MyObject> obj =-
473 QSharedPointer<MyObject>(new MyObject, doDeleteLater);-
474-
475 // continue using obj-
476 obj.clear(); // calls obj->deleteLater();-
477 }-
478 \endcode-
479-
480 It is also possible to specify a member function directly, as in:-
481 \code-
482 QSharedPointer<MyObject> obj =-
483 QSharedPointer<MyObject>(new MyObject, &QObject::deleteLater);-
484 \endcode-
485-
486 \sa clear()-
487*/-
488-
489/*!-
490 \fn QSharedPointer::QSharedPointer(const QSharedPointer<T> &other)-
491-
492 Creates a QSharedPointer object that shares \a other's pointer.-
493-
494 If \tt T is a derived type of the template parameter of this class,-
495 QSharedPointer will perform an automatic cast. Otherwise, you will-
496 get a compiler error.-
497*/-
498-
499/*!-
500 \fn QSharedPointer::QSharedPointer(const QWeakPointer<T> &other)-
501-
502 Creates a QSharedPointer by promoting the weak reference \a other-
503 to strong reference and sharing its pointer.-
504-
505 If \tt T is a derived type of the template parameter of this-
506 class, QSharedPointer will perform an automatic cast. Otherwise,-
507 you will get a compiler error.-
508-
509 \sa QWeakPointer::toStrongRef()-
510*/-
511-
512/*!-
513 \fn QSharedPointer &QSharedPointer::operator=(const QSharedPointer<T> &other)-
514-
515 Makes this object share \a other's pointer. The current pointer-
516 reference is discarded and, if it was the last, the pointer will-
517 be deleted.-
518-
519 If \tt T is a derived type of the template parameter of this-
520 class, QSharedPointer will perform an automatic cast. Otherwise,-
521 you will get a compiler error.-
522*/-
523-
524/*!-
525 \fn QSharedPointer &QSharedPointer::operator=(const QWeakPointer<T> &other)-
526-
527 Promotes \a other to a strong reference and makes this object-
528 share a reference to the pointer referenced by it. The current pointer-
529 reference is discarded and, if it was the last, the pointer will-
530 be deleted.-
531-
532 If \tt T is a derived type of the template parameter of this-
533 class, QSharedPointer will perform an automatic cast. Otherwise,-
534 you will get a compiler error.-
535*/-
536-
537/*!-
538 \fn void QSharedPointer::swap(QSharedPointer<T> &other);-
539 \since 5.3-
540-
541 Swaps this shared pointer instance with \a other. This function is-
542 very fast and never fails.-
543*/-
544-
545/*!-
546 \fn T *QSharedPointer::data() const-
547-
548 Returns the value of the pointer referenced by this object.-
549-
550 Note: do not delete the pointer returned by this function or pass-
551 it to another function that could delete it, including creating-
552 QSharedPointer or QWeakPointer objects.-
553*/-
554-
555/*!-
556 \fn T &QSharedPointer::operator *() const-
557-
558 Provides access to the shared pointer's members.-
559-
560 \sa isNull()-
561*/-
562-
563/*!-
564 \fn T *QSharedPointer::operator ->() const-
565-
566 Provides access to the shared pointer's members.-
567-
568 \sa isNull()-
569*/-
570-
571/*!-
572 \fn bool QSharedPointer::isNull() const-
573-
574 Returns \c true if this object is holding a reference to a null-
575 pointer.-
576*/-
577-
578/*!-
579 \fn QSharedPointer::operator bool() const-
580-
581 Returns \c true if this object is not null. This function is suitable-
582 for use in \tt if-constructs, like:-
583-
584 \code-
585 if (sharedptr) { ... }-
586 \endcode-
587-
588 \sa isNull()-
589*/-
590-
591/*!-
592 \fn bool QSharedPointer::operator !() const-
593-
594 Returns \c true if this object is null. This function is suitable-
595 for use in \tt if-constructs, like:-
596-
597 \code-
598 if (!sharedptr) { ... }-
599 \endcode-
600-
601 \sa isNull()-
602*/-
603-
604/*!-
605 \fn QSharedPointer<X> QSharedPointer::staticCast() const-
606-
607 Performs a static cast from this pointer's type to \tt X and returns-
608 a QSharedPointer that shares the reference. This function can be-
609 used for up- and for down-casting, but is more useful for-
610 up-casting.-
611-
612 Note: the template type \c X must have the same const and volatile-
613 qualifiers as the template of this object, or the cast will-
614 fail. Use constCast() if you need to drop those qualifiers.-
615-
616 \sa dynamicCast(), constCast(), qSharedPointerCast()-
617*/-
618-
619/*!-
620 \fn QSharedPointer<X> QSharedPointer::dynamicCast() const-
621-
622 Performs a dynamic cast from this pointer's type to \tt X and-
623 returns a QSharedPointer that shares the reference. If this-
624 function is used to up-cast, then QSharedPointer will perform a \tt-
625 dynamic_cast, which means that if the object being pointed by this-
626 QSharedPointer is not of type \tt X, the returned object will be-
627 null.-
628-
629 Note: the template type \c X must have the same const and volatile-
630 qualifiers as the template of this object, or the cast will-
631 fail. Use constCast() if you need to drop those qualifiers.-
632-
633 \sa qSharedPointerDynamicCast()-
634*/-
635-
636/*!-
637 \fn QSharedPointer<X> QSharedPointer::constCast() const-
638-
639 Performs a \tt const_cast from this pointer's type to \tt X and returns-
640 a QSharedPointer that shares the reference. This function can be-
641 used for up- and for down-casting, but is more useful for-
642 up-casting.-
643-
644 \sa isNull(), qSharedPointerConstCast()-
645*/-
646-
647/*!-
648 \fn QSharedPointer<X> QSharedPointer::objectCast() const-
649 \since 4.6-
650-
651 Performs a \l qobject_cast() from this pointer's type to \tt X and-
652 returns a QSharedPointer that shares the reference. If this-
653 function is used to up-cast, then QSharedPointer will perform a \tt-
654 qobject_cast, which means that if the object being pointed by this-
655 QSharedPointer is not of type \tt X, the returned object will be-
656 null.-
657-
658 Note: the template type \c X must have the same const and volatile-
659 qualifiers as the template of this object, or the cast will-
660 fail. Use constCast() if you need to drop those qualifiers.-
661-
662 \sa qSharedPointerObjectCast()-
663*/-
664-
665/*!-
666 \fn QSharedPointer<T> QSharedPointer::create()-
667 \since 5.1-
668-
669 Creates a QSharedPointer object and allocates a new item of type \tt T. The-
670 QSharedPointer internals and the object are allocated in one single memory-
671 allocation, which could help reduce memory fragmentation in a long-running-
672 application.-
673-
674 This function calls the default constructor for type \tt T.-
675*/-
676-
677/*!-
678 \fn QSharedPointer<T> QSharedPointer::create(...)-
679 \overload-
680 \since 5.1-
681-
682 Creates a QSharedPointer object and allocates a new item of type \tt T. The-
683 QSharedPointer internals and the object are allocated in one single memory-
684 allocation, which could help reduce memory fragmentation in a long-running-
685 application.-
686-
687 This function will attempt to call a constructor for type \tt T that can-
688 accept all the arguments passed. Arguments will be perfectly-forwarded.-
689-
690 \note This function is only fully available with a C++11 compiler that-
691 supports perfect forwarding of an arbitrary number of arguments.-
692-
693 If the compiler does not support the necessary C++11 features,-
694 then a restricted version is available since Qt 5.4: you may pass-
695 one (but just one) argument, and it will always be passed by const-
696 reference.-
697-
698 If you target Qt before version 5.4, you must use the overload-
699 that calls the default constructor.-
700*/-
701-
702/*!-
703 \fn QWeakPointer<T> QSharedPointer::toWeakRef() const-
704-
705 Returns a weak reference object that shares the pointer referenced-
706 by this object.-
707-
708 \sa QWeakPointer::QWeakPointer()-
709*/-
710-
711/*!-
712 \fn void QSharedPointer::clear()-
713-
714 Clears this QSharedPointer object, dropping the reference that it-
715 may have had to the pointer. If this was the last reference, then-
716 the pointer itself will be deleted.-
717*/-
718-
719/*!-
720 \fn void QSharedPointer::reset()-
721 \since 5.0-
722-
723 Same as clear(). For std::shared_ptr compatibility.-
724*/-
725-
726/*!-
727 \fn void QSharedPointer::reset(T *t)-
728 \since 5.0-
729-
730 Resets this QSharedPointer object to point to \a t-
731 instead. Equivalent to:-
732 \code-
733 QSharedPointer<T> other(t); this->swap(other);-
734 \endcode-
735*/-
736-
737/*!-
738 \fn void QSharedPointer::reset(T *t, Deleter deleter)-
739 \since 5.0-
740-
741 Resets this QSharedPointer object to point to \a t-
742 instead, with deleter \a deleter. Equivalent to:-
743 \code-
744 QSharedPointer<T> other(t, deleter); this->swap(other);-
745 \endcode-
746*/-
747-
748/*!-
749 \fn QWeakPointer::QWeakPointer()-
750-
751 Creates a QWeakPointer that points to nothing.-
752*/-
753-
754/*!-
755 \fn QWeakPointer::~QWeakPointer()-
756-
757 Destroys this QWeakPointer object. The pointer referenced-
758 by this object will not be deleted.-
759*/-
760-
761/*!-
762 \fn QWeakPointer::QWeakPointer(const QWeakPointer<T> &other)-
763-
764 Creates a QWeakPointer that holds a weak reference to the-
765 pointer referenced by \a other.-
766-
767 If \tt T is a derived type of the template parameter of this-
768 class, QWeakPointer will perform an automatic cast. Otherwise,-
769 you will get a compiler error.-
770*/-
771-
772/*!-
773 \fn QWeakPointer::QWeakPointer(const QSharedPointer<T> &other)-
774-
775 Creates a QWeakPointer that holds a weak reference to the-
776 pointer referenced by \a other.-
777-
778 If \tt T is a derived type of the template parameter of this-
779 class, QWeakPointer will perform an automatic cast. Otherwise,-
780 you will get a compiler error.-
781*/-
782-
783/*!-
784 \fn QWeakPointer::QWeakPointer(const QObject *obj)-
785 \since 4.6-
786 \deprecated-
787-
788 Creates a QWeakPointer that holds a weak reference directly to the-
789 QObject \a obj. This constructor is only available if the template type-
790 \tt T is QObject or derives from it (otherwise a compilation error will-
791 result).-
792-
793 You can use this constructor with any QObject, even if they were not-
794 created with \l QSharedPointer.-
795-
796 Note that QWeakPointers created this way on arbitrary QObjects usually-
797 cannot be promoted to QSharedPointer.-
798-
799 \sa QSharedPointer, QPointer-
800*/-
801-
802/*!-
803 \fn QWeakPointer &QWeakPointer::operator=(const QObject *obj)-
804 \since 4.6-
805 \deprecated-
806-
807 Makes this QWeakPointer hold a weak reference directly to the QObject-
808 \a obj. This function is only available if the template type \tt T is-
809 QObject or derives from it.-
810-
811 \sa QPointer-
812*/-
813-
814/*!-
815 \fn QWeakPointer &QWeakPointer::operator=(const QWeakPointer<T> &other)-
816-
817 Makes this object share \a other's pointer. The current pointer-
818 reference is discarded but is not deleted.-
819-
820 If \tt T is a derived type of the template parameter of this-
821 class, QWeakPointer will perform an automatic cast. Otherwise,-
822 you will get a compiler error.-
823*/-
824-
825/*!-
826 \fn QWeakPointer &QWeakPointer::operator=(const QSharedPointer<T> &other)-
827-
828 Makes this object share \a other's pointer. The current pointer-
829 reference is discarded but is not deleted.-
830-
831 If \tt T is a derived type of the template parameter of this-
832 class, QWeakPointer will perform an automatic cast. Otherwise,-
833 you will get a compiler error.-
834*/-
835-
836/*!-
837 \fn void QWeakPointer::swap(QWeakPointer<T> &other)-
838 \since 5.4-
839-
840 Swaps this weak pointer instance with \a other. This function is-
841 very fast and never fails.-
842*/-
843-
844/*!-
845 \fn bool QWeakPointer::isNull() const-
846-
847 Returns \c true if this object is holding a reference to a null-
848 pointer.-
849-
850 Note that, due to the nature of weak references, the pointer that-
851 QWeakPointer references can become null at any moment, so-
852 the value returned from this function can change from false to-
853 true from one call to the next.-
854*/-
855-
856/*!-
857 \fn QWeakPointer::operator bool() const-
858-
859 Returns \c true if this object is not null. This function is suitable-
860 for use in \tt if-constructs, like:-
861-
862 \code-
863 if (weakref) { ... }-
864 \endcode-
865-
866 Note that, due to the nature of weak references, the pointer that-
867 QWeakPointer references can become null at any moment, so-
868 the value returned from this function can change from true to-
869 false from one call to the next.-
870-
871 \sa isNull()-
872*/-
873-
874/*!-
875 \fn bool QWeakPointer::operator !() const-
876-
877 Returns \c true if this object is null. This function is suitable-
878 for use in \tt if-constructs, like:-
879-
880 \code-
881 if (!weakref) { ... }-
882 \endcode-
883-
884 Note that, due to the nature of weak references, the pointer that-
885 QWeakPointer references can become null at any moment, so-
886 the value returned from this function can change from false to-
887 true from one call to the next.-
888-
889 \sa isNull()-
890*/-
891-
892/*!-
893 \fn T *QWeakPointer::data() const-
894 \since 4.6-
895-
896 Returns the value of the pointer being tracked by this QWeakPointer,-
897 \b without ensuring that it cannot get deleted. To have that guarantee,-
898 use toStrongRef(), which returns a QSharedPointer object. If this-
899 function can determine that the pointer has already been deleted, it-
900 returns 0.-
901-
902 It is ok to obtain the value of the pointer and using that value itself,-
903 like for example in debugging statements:-
904-
905 \code-
906 qDebug("Tracking %p", weakref.data());-
907 \endcode-
908-
909 However, dereferencing the pointer is only allowed if you can guarantee-
910 by external means that the pointer does not get deleted. For example,-
911 if you can be certain that no other thread can delete it, nor the-
912 functions that you may call.-
913-
914 If that is the case, then the following code is valid:-
915-
916 \code-
917 // this pointer cannot be used in another thread-
918 // so other threads cannot delete it-
919 QWeakPointer<int> weakref = obtainReference();-
920-
921 Object *obj = weakref.data();-
922 if (obj) {-
923 // if the pointer wasn't deleted yet, we know it can't get-
924 // deleted by our own code here nor the functions we call-
925 otherFunction(obj);-
926 }-
927 \endcode-
928-
929 Use this function with care.-
930-
931 \sa isNull(), toStrongRef()-
932*/-
933-
934/*!-
935 \fn QSharedPointer<T> QWeakPointer::toStrongRef() const-
936-
937 Promotes this weak reference to a strong one and returns a-
938 QSharedPointer object holding that reference. When promoting to-
939 QSharedPointer, this function verifies if the object has been deleted-
940 already or not. If it hasn't, this function increases the reference-
941 count to the shared object, thus ensuring that it will not get-
942 deleted.-
943-
944 Since this function can fail to obtain a valid strong reference to the-
945 shared object, you should always verify if the conversion succeeded,-
946 by calling QSharedPointer::isNull() on the returned object.-
947-
948 For example, the following code promotes a QWeakPointer that was held-
949 to a strong reference and, if it succeeded, it prints the value of the-
950 integer that was held:-
951-
952 \code-
953 QWeakPointer<int> weakref;-
954-
955 // ...-
956-
957 QSharedPointer<int> strong = weakref.toStrongRef();-
958 if (strong)-
959 qDebug() << "The value is:" << *strong;-
960 else-
961 qDebug() << "The value has already been deleted";-
962 \endcode-
963-
964 \sa QSharedPointer::QSharedPointer()-
965*/-
966-
967/*!-
968 \fn QSharedPointer<T> QWeakPointer::lock() const-
969 \since 5.4-
970-
971 Same as toStrongRef().-
972-
973 This function is provided for API compatibility with std::weak_ptr.-
974*/-
975-
976/*!-
977 \fn void QWeakPointer::clear()-
978-
979 Clears this QWeakPointer object, dropping the reference that it-
980 may have had to the pointer.-
981*/-
982-
983/*!-
984 \fn QSharedPointer<T> QEnableSharedFromThis::sharedFromThis()-
985 \since 5.4-
986-
987 If \c this (that is, the subclass instance invoking this method) is being-
988 managed by a QSharedPointer, returns a shared pointer instance pointing to-
989 \c this; otherwise returns a QSharedPointer holding a null pointer.-
990*/-
991-
992/*!-
993 \fn QSharedPointer<const T> QEnableSharedFromThis::sharedFromThis() const-
994 \overload-
995 \since 5.4-
996-
997 Const overload of sharedFromThis().-
998*/-
999-
1000/*!-
1001 \fn bool operator==(const QSharedPointer<T> &ptr1, const QSharedPointer<X> &ptr2)-
1002 \relates QSharedPointer-
1003-
1004 Returns \c true if the pointer referenced by \a ptr1 is the-
1005 same pointer as that referenced by \a ptr2.-
1006-
1007 If \a ptr2's template parameter is different from \a ptr1's,-
1008 QSharedPointer will attempt to perform an automatic \tt static_cast-
1009 to ensure that the pointers being compared are equal. If \a ptr2's-
1010 template parameter is not a base or a derived type from-
1011 \a ptr1's, you will get a compiler error.-
1012*/-
1013-
1014/*!-
1015 \fn bool operator!=(const QSharedPointer<T> &ptr1, const QSharedPointer<X> &ptr2)-
1016 \relates QSharedPointer-
1017-
1018 Returns \c true if the pointer referenced by \a ptr1 is not the-
1019 same pointer as that referenced by \a ptr2.-
1020-
1021 If \a ptr2's template parameter is different from \a ptr1's,-
1022 QSharedPointer will attempt to perform an automatic \tt static_cast-
1023 to ensure that the pointers being compared are equal. If \a ptr2's-
1024 template parameter is not a base or a derived type from-
1025 \a ptr1's, you will get a compiler error.-
1026*/-
1027-
1028/*!-
1029 \fn bool operator==(const QSharedPointer<T> &ptr1, const X *ptr2)-
1030 \relates QSharedPointer-
1031-
1032 Returns \c true if the pointer referenced by \a ptr1 is the-
1033 same pointer as \a ptr2.-
1034-
1035 If \a ptr2's type is different from \a ptr1's,-
1036 QSharedPointer will attempt to perform an automatic \tt static_cast-
1037 to ensure that the pointers being compared are equal. If \a ptr2's-
1038 type is not a base or a derived type from this-
1039 \a ptr1's, you will get a compiler error.-
1040*/-
1041-
1042/*!-
1043 \fn bool operator!=(const QSharedPointer<T> &ptr1, const X *ptr2)-
1044 \relates QSharedPointer-
1045-
1046 Returns \c true if the pointer referenced by \a ptr1 is not the-
1047 same pointer as \a ptr2.-
1048-
1049 If \a ptr2's type is different from \a ptr1's,-
1050 QSharedPointer will attempt to perform an automatic \tt static_cast-
1051 to ensure that the pointers being compared are equal. If \a ptr2's-
1052 type is not a base or a derived type from this-
1053 \a ptr1's, you will get a compiler error.-
1054*/-
1055-
1056/*!-
1057 \fn bool operator==(const T *ptr1, const QSharedPointer<X> &ptr2)-
1058 \relates QSharedPointer-
1059-
1060 Returns \c true if the pointer \a ptr1 is the-
1061 same pointer as that referenced by \a ptr2.-
1062-
1063 If \a ptr2's template parameter is different from \a ptr1's type,-
1064 QSharedPointer will attempt to perform an automatic \tt static_cast-
1065 to ensure that the pointers being compared are equal. If \a ptr2's-
1066 template parameter is not a base or a derived type from-
1067 \a ptr1's type, you will get a compiler error.-
1068*/-
1069-
1070/*!-
1071 \fn bool operator!=(const T *ptr1, const QSharedPointer<X> &ptr2)-
1072 \relates QSharedPointer-
1073-
1074 Returns \c true if the pointer \a ptr1 is not the-
1075 same pointer as that referenced by \a ptr2.-
1076-
1077 If \a ptr2's template parameter is different from \a ptr1's type,-
1078 QSharedPointer will attempt to perform an automatic \tt static_cast-
1079 to ensure that the pointers being compared are equal. If \a ptr2's-
1080 template parameter is not a base or a derived type from-
1081 \a ptr1's type, you will get a compiler error.-
1082*/-
1083-
1084/*!-
1085 \fn bool operator==(const QSharedPointer<T> &ptr1, const QWeakPointer<X> &ptr2)-
1086 \relates QWeakPointer-
1087-
1088 Returns \c true if the pointer referenced by \a ptr1 is the-
1089 same pointer as that referenced by \a ptr2.-
1090-
1091 If \a ptr2's template parameter is different from \a ptr1's,-
1092 QSharedPointer will attempt to perform an automatic \tt static_cast-
1093 to ensure that the pointers being compared are equal. If \a ptr2's-
1094 template parameter is not a base or a derived type from-
1095 \a ptr1's, you will get a compiler error.-
1096*/-
1097-
1098/*!-
1099 \fn bool operator!=(const QSharedPointer<T> &ptr1, const QWeakPointer<X> &ptr2)-
1100 \relates QWeakPointer-
1101-
1102 Returns \c true if the pointer referenced by \a ptr1 is not the-
1103 same pointer as that referenced by \a ptr2.-
1104-
1105 If \a ptr2's template parameter is different from \a ptr1's,-
1106 QSharedPointer will attempt to perform an automatic \tt static_cast-
1107 to ensure that the pointers being compared are equal. If \a ptr2's-
1108 template parameter is not a base or a derived type from-
1109 \a ptr1's, you will get a compiler error.-
1110*/-
1111-
1112/*!-
1113 \fn bool operator==(const QWeakPointer<T> &ptr1, const QSharedPointer<X> &ptr2)-
1114 \relates QWeakPointer-
1115-
1116 Returns \c true if the pointer referenced by \a ptr1 is the-
1117 same pointer as that referenced by \a ptr2.-
1118-
1119 If \a ptr2's template parameter is different from \a ptr1's,-
1120 QSharedPointer will attempt to perform an automatic \tt static_cast-
1121 to ensure that the pointers being compared are equal. If \a ptr2's-
1122 template parameter is not a base or a derived type from-
1123 \a ptr1's, you will get a compiler error.-
1124*/-
1125-
1126/*!-
1127 \fn bool operator!=(const QWeakPointer<T> &ptr1, const QSharedPointer<X> &ptr2)-
1128 \relates QWeakPointer-
1129-
1130 Returns \c true if the pointer referenced by \a ptr1 is not the-
1131 same pointer as that referenced by \a ptr2.-
1132-
1133 If \a ptr2's template parameter is different from \a ptr1's,-
1134 QSharedPointer will attempt to perform an automatic \tt static_cast-
1135 to ensure that the pointers being compared are equal. If \a ptr2's-
1136 template parameter is not a base or a derived type from-
1137 \a ptr1's, you will get a compiler error.-
1138*/-
1139-
1140/*!-
1141 \fn QSharedPointer<X> qSharedPointerCast(const QSharedPointer<T> &other)-
1142 \relates QSharedPointer-
1143-
1144 Returns a shared pointer to the pointer held by \a other, cast to-
1145 type \tt X. The types \tt T and \tt X must belong to one-
1146 hierarchy for the \tt static_cast to succeed.-
1147-
1148 Note that \tt X must have the same cv-qualifiers (\tt const and-
1149 \tt volatile) that \tt T has, or the code will fail to-
1150 compile. Use qSharedPointerConstCast to cast away the constness.-
1151-
1152 \sa QSharedPointer::staticCast(), qSharedPointerDynamicCast(), qSharedPointerConstCast()-
1153*/-
1154-
1155/*!-
1156 \fn QSharedPointer<X> qSharedPointerCast(const QWeakPointer<T> &other)-
1157 \relates QSharedPointer-
1158 \relates QWeakPointer-
1159-
1160 Returns a shared pointer to the pointer held by \a other, cast to-
1161 type \tt X. The types \tt T and \tt X must belong to one-
1162 hierarchy for the \tt static_cast to succeed.-
1163-
1164 The \a other object is converted first to a strong reference. If-
1165 that conversion fails (because the object it's pointing to has-
1166 already been deleted), this function returns a null-
1167 QSharedPointer.-
1168-
1169 Note that \tt X must have the same cv-qualifiers (\tt const and-
1170 \tt volatile) that \tt T has, or the code will fail to-
1171 compile. Use qSharedPointerConstCast to cast away the constness.-
1172-
1173 \sa QWeakPointer::toStrongRef(), qSharedPointerDynamicCast(), qSharedPointerConstCast()-
1174*/-
1175-
1176/*!-
1177 \fn QSharedPointer<X> qSharedPointerDynamicCast(const QSharedPointer<T> &other)-
1178 \relates QSharedPointer-
1179-
1180 Returns a shared pointer to the pointer held by \a other, using a-
1181 dynamic cast to type \tt X to obtain an internal pointer of the-
1182 appropriate type. If the \tt dynamic_cast fails, the object-
1183 returned will be null.-
1184-
1185 Note that \tt X must have the same cv-qualifiers (\tt const and-
1186 \tt volatile) that \tt T has, or the code will fail to-
1187 compile. Use qSharedPointerConstCast to cast away the constness.-
1188-
1189 \sa QSharedPointer::dynamicCast(), qSharedPointerCast(), qSharedPointerConstCast()-
1190*/-
1191-
1192/*!-
1193 \fn QSharedPointer<X> qSharedPointerDynamicCast(const QWeakPointer<T> &other)-
1194 \relates QSharedPointer-
1195 \relates QWeakPointer-
1196-
1197 Returns a shared pointer to the pointer held by \a other, using a-
1198 dynamic cast to type \tt X to obtain an internal pointer of the-
1199 appropriate type. If the \tt dynamic_cast fails, the object-
1200 returned will be null.-
1201-
1202 The \a other object is converted first to a strong reference. If-
1203 that conversion fails (because the object it's pointing to has-
1204 already been deleted), this function also returns a null-
1205 QSharedPointer.-
1206-
1207 Note that \tt X must have the same cv-qualifiers (\tt const and-
1208 \tt volatile) that \tt T has, or the code will fail to-
1209 compile. Use qSharedPointerConstCast to cast away the constness.-
1210-
1211 \sa QWeakPointer::toStrongRef(), qSharedPointerCast(), qSharedPointerConstCast()-
1212*/-
1213-
1214/*!-
1215 \fn QSharedPointer<X> qSharedPointerConstCast(const QSharedPointer<T> &other)-
1216 \relates QSharedPointer-
1217-
1218 Returns a shared pointer to the pointer held by \a other, cast to-
1219 type \tt X. The types \tt T and \tt X must belong to one-
1220 hierarchy for the \tt const_cast to succeed. The \tt const and \tt-
1221 volatile differences between \tt T and \tt X are ignored.-
1222-
1223 \sa QSharedPointer::constCast(), qSharedPointerCast(), qSharedPointerDynamicCast()-
1224*/-
1225-
1226/*!-
1227 \fn QSharedPointer<X> qSharedPointerConstCast(const QWeakPointer<T> &other)-
1228 \relates QSharedPointer-
1229 \relates QWeakPointer-
1230-
1231 Returns a shared pointer to the pointer held by \a other, cast to-
1232 type \tt X. The types \tt T and \tt X must belong to one-
1233 hierarchy for the \tt const_cast to succeed. The \tt const and-
1234 \tt volatile differences between \tt T and \tt X are ignored.-
1235-
1236 The \a other object is converted first to a strong reference. If-
1237 that conversion fails (because the object it's pointing to has-
1238 already been deleted), this function returns a null-
1239 QSharedPointer.-
1240-
1241 \sa QWeakPointer::toStrongRef(), qSharedPointerCast(), qSharedPointerDynamicCast()-
1242*/-
1243-
1244/*!-
1245 \fn QSharedPointer<X> qSharedPointerObjectCast(const QSharedPointer<T> &other)-
1246 \relates QSharedPointer-
1247 \since 4.6-
1248-
1249 \brief The qSharedPointerObjectCast function is for casting a shared pointer.-
1250-
1251 Returns a shared pointer to the pointer held by \a other, using a-
1252 \l qobject_cast() to type \tt X to obtain an internal pointer of the-
1253 appropriate type. If the \tt qobject_cast fails, the object-
1254 returned will be null.-
1255-
1256 Note that \tt X must have the same cv-qualifiers (\tt const and-
1257 \tt volatile) that \tt T has, or the code will fail to-
1258 compile. Use qSharedPointerConstCast to cast away the constness.-
1259-
1260 \sa QSharedPointer::objectCast(), qSharedPointerCast(), qSharedPointerConstCast()-
1261*/-
1262-
1263/*!-
1264 \fn QSharedPointer<X> qSharedPointerObjectCast(const QWeakPointer<T> &other)-
1265 \relates QSharedPointer-
1266 \relates QWeakPointer-
1267 \since 4.6-
1268-
1269 \brief The qSharedPointerObjectCast function is for casting a shared pointer.-
1270-
1271 Returns a shared pointer to the pointer held by \a other, using a-
1272 \l qobject_cast() to type \tt X to obtain an internal pointer of the-
1273 appropriate type. If the \tt qobject_cast fails, the object-
1274 returned will be null.-
1275-
1276 The \a other object is converted first to a strong reference. If-
1277 that conversion fails (because the object it's pointing to has-
1278 already been deleted), this function also returns a null-
1279 QSharedPointer.-
1280-
1281 Note that \tt X must have the same cv-qualifiers (\tt const and-
1282 \tt volatile) that \tt T has, or the code will fail to-
1283 compile. Use qSharedPointerConstCast to cast away the constness.-
1284-
1285 \sa QWeakPointer::toStrongRef(), qSharedPointerCast(), qSharedPointerConstCast()-
1286*/-
1287-
1288-
1289/*!-
1290 \fn QWeakPointer<X> qWeakPointerCast(const QWeakPointer<T> &other)-
1291 \relates QWeakPointer-
1292-
1293 Returns a weak pointer to the pointer held by \a other, cast to-
1294 type \tt X. The types \tt T and \tt X must belong to one-
1295 hierarchy for the \tt static_cast to succeed.-
1296-
1297 Note that \tt X must have the same cv-qualifiers (\tt const and-
1298 \tt volatile) that \tt T has, or the code will fail to-
1299 compile. Use qSharedPointerConstCast to cast away the constness.-
1300*/-
1301-
1302#include <qset.h>-
1303#include <qmutex.h>-
1304-
1305#if !defined(QT_NO_QOBJECT)-
1306#include "private/qobject_p.h"-
1307-
1308QT_BEGIN_NAMESPACE-
1309-
1310/*!-
1311 \internal-
1312 This function is called for a just-created QObject \a obj, to enable-
1313 the use of QSharedPointer and QWeakPointer in the future.-
1314 */-
1315void QtSharedPointer::ExternalRefCountData::setQObjectShared(const QObject *, bool)-
1316{}-
1317-
1318/*!-
1319 \internal-
1320 This function is called when a QSharedPointer is created from a QWeakPointer-
1321-
1322 We check that the QWeakPointer was really created from a QSharedPointer, and-
1323 not from a QObject.-
1324*/-
1325void QtSharedPointer::ExternalRefCountData::checkQObjectShared(const QObject *)-
1326{-
1327 if (strongref.load() < 0)
strongref.load() < 0Description
TRUEevaluated 2 times by 1 test
Evaluated by:
  • tst_QSharedPointer
FALSEevaluated 60 times by 5 tests
Evaluated by:
  • tst_QAbstractNetworkCache
  • tst_QNetworkAccessManager_And_QProgressDialog
  • tst_QNetworkDiskCache
  • tst_QSharedPointer
  • tst_Spdy
2-60
1328 qWarning("QSharedPointer: cannot create a QSharedPointer from a QObject-tracking QWeakPointer");
executed 2 times by 1 test: QMessageLogger(__FILE__, 1328, __PRETTY_FUNCTION__).warning("QSharedPointer: cannot create a QSharedPointer from a QObject-tracking QWeakPointer");
Executed by:
  • tst_QSharedPointer
2
1329}
executed 62 times by 5 tests: end of block
Executed by:
  • tst_QAbstractNetworkCache
  • tst_QNetworkAccessManager_And_QProgressDialog
  • tst_QNetworkDiskCache
  • tst_QSharedPointer
  • tst_Spdy
62
1330-
1331QtSharedPointer::ExternalRefCountData *QtSharedPointer::ExternalRefCountData::getAndRef(const QObject *obj)-
1332{-
1333 Q_ASSERT(obj);-
1334 QObjectPrivate *d = QObjectPrivate::get(const_cast<QObject *>(obj));-
1335 Q_ASSERT_X(!d->wasDeleted, "QWeakPointer", "Detected QWeakPointer creation in a QObject being deleted");-
1336-
1337 ExternalRefCountData *that = d->sharedRefcount.load();-
1338 if (that) {
thatDescription
TRUEevaluated 217414 times by 223 tests
Evaluated by:
  • tst_Gestures
  • tst_ModelTest
  • tst_NetworkSelfTest
  • tst_QAbstractAnimation
  • tst_QAbstractButton
  • tst_QAbstractItemView
  • tst_QAbstractNetworkCache
  • tst_QAbstractPrintDialog
  • tst_QAbstractScrollArea
  • tst_QAbstractSlider
  • tst_QAbstractSpinBox
  • tst_QAccessibility
  • tst_QAction
  • tst_QActionGroup
  • tst_QAnimationGroup
  • tst_QApplication
  • tst_QBackingStore
  • tst_QBoxLayout
  • tst_QBrush
  • tst_QButtonGroup
  • tst_QCalendarWidget
  • tst_QCheckBox
  • tst_QColorDialog
  • tst_QColumnView
  • tst_QComboBox
  • ...
FALSEevaluated 68025 times by 243 tests
Evaluated by:
  • tst_Gestures
  • tst_ModelTest
  • tst_NetworkSelfTest
  • tst_QAbstractAnimation
  • tst_QAbstractButton
  • tst_QAbstractItemView
  • tst_QAbstractNetworkCache
  • tst_QAbstractPrintDialog
  • tst_QAbstractScrollArea
  • tst_QAbstractSlider
  • tst_QAbstractSpinBox
  • tst_QAbstractTextDocumentLayout
  • tst_QAccessibility
  • tst_QAction
  • tst_QActionGroup
  • tst_QAnimationGroup
  • tst_QApplication
  • tst_QBackingStore
  • tst_QBoxLayout
  • tst_QBrush
  • tst_QBuffer
  • tst_QButtonGroup
  • tst_QCalendarWidget
  • tst_QCheckBox
  • tst_QColorDialog
  • ...
68025-217414
1339 that->weakref.ref();-
1340 return that;
executed 217414 times by 223 tests: return that;
Executed by:
  • tst_Gestures
  • tst_ModelTest
  • tst_NetworkSelfTest
  • tst_QAbstractAnimation
  • tst_QAbstractButton
  • tst_QAbstractItemView
  • tst_QAbstractNetworkCache
  • tst_QAbstractPrintDialog
  • tst_QAbstractScrollArea
  • tst_QAbstractSlider
  • tst_QAbstractSpinBox
  • tst_QAccessibility
  • tst_QAction
  • tst_QActionGroup
  • tst_QAnimationGroup
  • tst_QApplication
  • tst_QBackingStore
  • tst_QBoxLayout
  • tst_QBrush
  • tst_QButtonGroup
  • tst_QCalendarWidget
  • tst_QCheckBox
  • tst_QColorDialog
  • tst_QColumnView
  • tst_QComboBox
  • ...
217414
1341 }-
1342-
1343 // we can create the refcount data because it doesn't exist-
1344 ExternalRefCountData *x = new ExternalRefCountData(Qt::Uninitialized);-
1345 x->strongref.store(-1);-
1346 x->weakref.store(2); // the QWeakPointer that called us plus the QObject itself-
1347 if (!d->sharedRefcount.testAndSetRelease(0, x)) {
!d->sharedRefc...tRelease(0, x)Description
TRUEnever evaluated
FALSEevaluated 68025 times by 243 tests
Evaluated by:
  • tst_Gestures
  • tst_ModelTest
  • tst_NetworkSelfTest
  • tst_QAbstractAnimation
  • tst_QAbstractButton
  • tst_QAbstractItemView
  • tst_QAbstractNetworkCache
  • tst_QAbstractPrintDialog
  • tst_QAbstractScrollArea
  • tst_QAbstractSlider
  • tst_QAbstractSpinBox
  • tst_QAbstractTextDocumentLayout
  • tst_QAccessibility
  • tst_QAction
  • tst_QActionGroup
  • tst_QAnimationGroup
  • tst_QApplication
  • tst_QBackingStore
  • tst_QBoxLayout
  • tst_QBrush
  • tst_QBuffer
  • tst_QButtonGroup
  • tst_QCalendarWidget
  • tst_QCheckBox
  • tst_QColorDialog
  • ...
0-68025
1348 delete x;-
1349 x = d->sharedRefcount.loadAcquire();-
1350 x->weakref.ref();-
1351 }
never executed: end of block
0
1352 return x;
executed 68025 times by 243 tests: return x;
Executed by:
  • tst_Gestures
  • tst_ModelTest
  • tst_NetworkSelfTest
  • tst_QAbstractAnimation
  • tst_QAbstractButton
  • tst_QAbstractItemView
  • tst_QAbstractNetworkCache
  • tst_QAbstractPrintDialog
  • tst_QAbstractScrollArea
  • tst_QAbstractSlider
  • tst_QAbstractSpinBox
  • tst_QAbstractTextDocumentLayout
  • tst_QAccessibility
  • tst_QAction
  • tst_QActionGroup
  • tst_QAnimationGroup
  • tst_QApplication
  • tst_QBackingStore
  • tst_QBoxLayout
  • tst_QBrush
  • tst_QBuffer
  • tst_QButtonGroup
  • tst_QCalendarWidget
  • tst_QCheckBox
  • tst_QColorDialog
  • ...
68025
1353}-
1354-
1355/**-
1356 \internal-
1357 Returns a QSharedPointer<QObject> if the variant contains-
1358 a QSharedPointer<T> where T inherits QObject. Otherwise the behaviour is undefined.-
1359*/-
1360QSharedPointer<QObject> QtSharedPointer::sharedPointerFromVariant_internal(const QVariant &variant)-
1361{-
1362 Q_ASSERT(QMetaType::typeFlags(variant.userType()) & QMetaType::SharedPointerToQObject);-
1363 return *reinterpret_cast<const QSharedPointer<QObject>*>(variant.constData());
executed 8 times by 2 tests: return *reinterpret_cast<const QSharedPointer<QObject>*>(variant.constData());
Executed by:
  • tst_QMetaType
  • tst_QSharedPointer
8
1364}-
1365-
1366/**-
1367 \internal-
1368 Returns a QWeakPointer<QObject> if the variant contains-
1369 a QWeakPointer<T> where T inherits QObject. Otherwise the behaviour is undefined.-
1370*/-
1371QWeakPointer<QObject> QtSharedPointer::weakPointerFromVariant_internal(const QVariant &variant)-
1372{-
1373 Q_ASSERT(QMetaType::typeFlags(variant.userType()) & QMetaType::WeakPointerToQObject || QMetaType::typeFlags(variant.userType()) & QMetaType::TrackingPointerToQObject);-
1374 return *reinterpret_cast<const QWeakPointer<QObject>*>(variant.constData());
executed 21 times by 3 tests: return *reinterpret_cast<const QWeakPointer<QObject>*>(variant.constData());
Executed by:
  • tst_QMetaType
  • tst_QPointer
  • tst_QSharedPointer
21
1375}-
1376-
1377QT_END_NAMESPACE-
1378-
1379#endif-
1380-
1381-
1382-
1383//# define QT_SHARED_POINTER_BACKTRACE_SUPPORT-
1384# ifdef QT_SHARED_POINTER_BACKTRACE_SUPPORT-
1385# if defined(__GLIBC__) && (__GLIBC__ >= 2) && !defined(__UCLIBC__) && !defined(QT_LINUXBASE)-
1386# define BACKTRACE_SUPPORTED-
1387# elif defined(Q_OS_MAC)-
1388# define BACKTRACE_SUPPORTED-
1389# endif-
1390# endif-
1391-
1392# if defined(BACKTRACE_SUPPORTED)-
1393# include <sys/types.h>-
1394# include <execinfo.h>-
1395# include <stdio.h>-
1396# include <unistd.h>-
1397# include <sys/wait.h>-
1398-
1399QT_BEGIN_NAMESPACE-
1400-
1401static inline QByteArray saveBacktrace() __attribute__((always_inline));-
1402static inline QByteArray saveBacktrace()-
1403{-
1404 static const int maxFrames = 32;-
1405-
1406 QByteArray stacktrace;-
1407 stacktrace.resize(sizeof(void*) * maxFrames);-
1408 int stack_size = backtrace((void**)stacktrace.data(), maxFrames);-
1409 stacktrace.resize(sizeof(void*) * stack_size);-
1410-
1411 return stacktrace;-
1412}-
1413-
1414static void printBacktrace(QByteArray stacktrace)-
1415{-
1416 void *const *stack = (void *const *)stacktrace.constData();-
1417 int stack_size = stacktrace.size() / sizeof(void*);-
1418 char **stack_symbols = backtrace_symbols(stack, stack_size);-
1419-
1420 int filter[2];-
1421 pid_t child = -1;-
1422 if (pipe(filter) != -1)-
1423 child = fork();-
1424 if (child == 0) {-
1425 // child process-
1426 dup2(fileno(stderr), fileno(stdout));-
1427 dup2(filter[0], fileno(stdin));-
1428 close(filter[0]);-
1429 close(filter[1]);-
1430 execlp("c++filt", "c++filt", "-n", NULL);-
1431-
1432 // execlp failed-
1433 execl("/bin/cat", "/bin/cat", NULL);-
1434 _exit(127);-
1435 }-
1436-
1437 // parent process-
1438 close(filter[0]);-
1439 FILE *output;-
1440 if (child == -1) {-
1441 // failed forking-
1442 close(filter[1]);-
1443 output = stderr;-
1444 } else {-
1445 output = fdopen(filter[1], "w");-
1446 }-
1447-
1448 fprintf(stderr, "Backtrace of the first creation (most recent frame first):\n");-
1449 for (int i = 0; i < stack_size; ++i) {-
1450 if (strlen(stack_symbols[i]))-
1451 fprintf(output, "#%-2d %s\n", i, stack_symbols[i]);-
1452 else-
1453 fprintf(output, "#%-2d %p\n", i, stack[i]);-
1454 }-
1455-
1456 if (child != -1) {-
1457 fclose(output);-
1458 waitpid(child, 0, 0);-
1459 }-
1460}-
1461-
1462QT_END_NAMESPACE-
1463-
1464# endif // BACKTRACE_SUPPORTED-
1465-
1466namespace {-
1467 QT_USE_NAMESPACE-
1468 struct Data {-
1469 const volatile void *pointer;-
1470# ifdef BACKTRACE_SUPPORTED-
1471 QByteArray backtrace;-
1472# endif-
1473 };-
1474-
1475 class KnownPointers-
1476 {-
1477 public:-
1478 QMutex mutex;-
1479 QHash<const void *, Data> dPointers;-
1480 QHash<const volatile void *, const void *> dataPointers;-
1481 };-
1482}-
1483-
1484Q_GLOBAL_STATIC(KnownPointers, knownPointers)
executed 2 times by 2 tests: end of block
Executed by:
  • tst_qsharedpointer - unknown status
  • tst_qsharedpointer_and_qwidget - unknown status
executed 2 times by 2 tests: guard.store(QtGlobalStatic::Destroyed);
Executed by:
  • tst_qsharedpointer - unknown status
  • tst_qsharedpointer_and_qwidget - unknown status
executed 387 times by 2 tests: return &holder.value;
Executed by:
  • tst_QSharedPointer
  • tst_QSharedPointer_and_QWidget
guard.load() =...c::InitializedDescription
TRUEevaluated 2 times by 2 tests
Evaluated by:
  • tst_qsharedpointer - unknown status
  • tst_qsharedpointer_and_qwidget - unknown status
FALSEnever evaluated
0-387
1485-
1486QT_BEGIN_NAMESPACE-
1487-
1488namespace QtSharedPointer {-
1489 Q_AUTOTEST_EXPORT void internalSafetyCheckCleanCheck();-
1490}-
1491-
1492/*!-
1493 \internal-
1494*/-
1495void QtSharedPointer::internalSafetyCheckAdd(const void *d_ptr, const volatile void *ptr)-
1496{-
1497 KnownPointers *const kp = knownPointers();-
1498 if (!kp)
!kpDescription
TRUEnever evaluated
FALSEevaluated 133 times by 1 test
Evaluated by:
  • tst_QSharedPointer
0-133
1499 return; // end-game: the application is being destroyed already
never executed: return;
0
1500-
1501 QMutexLocker lock(&kp->mutex);-
1502 Q_ASSERT(!kp->dPointers.contains(d_ptr));-
1503-
1504 //qDebug("Adding d=%p value=%p", d_ptr, ptr);-
1505-
1506 const void *other_d_ptr = kp->dataPointers.value(ptr, 0);-
1507 if (Q_UNLIKELY(other_d_ptr)) {
__builtin_expe...d_ptr), false)Description
TRUEnever evaluated
FALSEevaluated 133 times by 1 test
Evaluated by:
  • tst_QSharedPointer
0-133
1508# ifdef BACKTRACE_SUPPORTED-
1509 printBacktrace(knownPointers()->dPointers.value(other_d_ptr).backtrace);-
1510# endif-
1511 qFatal("QSharedPointer: internal self-check failed: pointer %p was already tracked "-
1512 "by another QSharedPointer object %p", ptr, other_d_ptr);-
1513 }
never executed: end of block
0
1514-
1515 Data data;-
1516 data.pointer = ptr;-
1517# ifdef BACKTRACE_SUPPORTED-
1518 data.backtrace = saveBacktrace();-
1519# endif-
1520-
1521 kp->dPointers.insert(d_ptr, data);-
1522 kp->dataPointers.insert(ptr, d_ptr);-
1523 Q_ASSERT(kp->dPointers.size() == kp->dataPointers.size());-
1524}
executed 133 times by 1 test: end of block
Executed by:
  • tst_QSharedPointer
133
1525-
1526/*!-
1527 \internal-
1528*/-
1529void QtSharedPointer::internalSafetyCheckRemove(const void *d_ptr)-
1530{-
1531 KnownPointers *const kp = knownPointers();-
1532 if (!kp)
!kpDescription
TRUEnever evaluated
FALSEevaluated 133 times by 1 test
Evaluated by:
  • tst_QSharedPointer
0-133
1533 return; // end-game: the application is being destroyed already
never executed: return;
0
1534-
1535 QMutexLocker lock(&kp->mutex);-
1536-
1537 const auto it = kp->dPointers.constFind(d_ptr);-
1538 if (Q_UNLIKELY(it == kp->dPointers.cend())) {
__builtin_expe...end()), false)Description
TRUEnever evaluated
FALSEevaluated 133 times by 1 test
Evaluated by:
  • tst_QSharedPointer
0-133
1539 qFatal("QSharedPointer: internal self-check inconsistency: pointer %p was not tracked. "-
1540 "To use QT_SHAREDPOINTER_TRACK_POINTERS, you have to enable it throughout "-
1541 "in your code.", d_ptr);-
1542 }
never executed: end of block
0
1543-
1544 const auto it2 = kp->dataPointers.constFind(it->pointer);-
1545 Q_ASSERT(it2 != kp->dataPointers.cend());-
1546-
1547 //qDebug("Removing d=%p value=%p", d_ptr, it->pointer);-
1548-
1549 // remove entries-
1550 kp->dataPointers.erase(it2);-
1551 kp->dPointers.erase(it);-
1552 Q_ASSERT(kp->dPointers.size() == kp->dataPointers.size());-
1553}
executed 133 times by 1 test: end of block
Executed by:
  • tst_QSharedPointer
133
1554-
1555/*!-
1556 \internal-
1557 Called by the QSharedPointer autotest-
1558*/-
1559void QtSharedPointer::internalSafetyCheckCleanCheck()-
1560{-
1561# ifdef QT_BUILD_INTERNAL-
1562 KnownPointers *const kp = knownPointers();-
1563 Q_ASSERT_X(kp, "internalSafetyCheckSelfCheck()", "Called after global statics deletion!");-
1564-
1565 if (Q_UNLIKELY(kp->dPointers.size() != kp->dataPointers.size()))
__builtin_expe...ize()), false)Description
TRUEnever evaluated
FALSEevaluated 121 times by 2 tests
Evaluated by:
  • tst_QSharedPointer
  • tst_QSharedPointer_and_QWidget
0-121
1566 qFatal("Internal consistency error: the number of pointers is not equal!");
never executed: QMessageLogger(__FILE__, 1566, __PRETTY_FUNCTION__).fatal("Internal consistency error: the number of pointers is not equal!");
0
1567-
1568 if (Q_UNLIKELY(!kp->dPointers.isEmpty()))
__builtin_expe...pty()), false)Description
TRUEnever evaluated
FALSEevaluated 121 times by 2 tests
Evaluated by:
  • tst_QSharedPointer
  • tst_QSharedPointer_and_QWidget
0-121
1569 qFatal("Pointer cleaning failed: %d entries remaining", kp->dPointers.size());
never executed: QMessageLogger(__FILE__, 1569, __PRETTY_FUNCTION__).fatal("Pointer cleaning failed: %d entries remaining", kp->dPointers.size());
0
1570# endif-
1571}
executed 121 times by 2 tests: end of block
Executed by:
  • tst_QSharedPointer
  • tst_QSharedPointer_and_QWidget
121
1572-
1573QT_END_NAMESPACE-
Source codeSwitch to Preprocessed file
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