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comparison: xpcom/glue/nsISupportsImpl.h

xpcom/glue/nsISupportsImpl.h

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1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5 // IWYU pragma: private, include "nsISupports.h"
6
7
8 #ifndef nsISupportsImpl_h__
9 #define nsISupportsImpl_h__
10
11 #include "nscore.h"
12 #include "nsISupportsBase.h"
13 #include "nsISupportsUtils.h"
14
15
16 #if !defined(XPCOM_GLUE_AVOID_NSPR)
17 #include "prthread.h" /* needed for thread-safety checks */
18 #endif // !XPCOM_GLUE_AVOID_NSPR
19
20 #include "nsDebug.h"
21 #include "nsXPCOM.h"
22 #ifndef XPCOM_GLUE
23 #include "mozilla/Atomics.h"
24 #endif
25 #include "mozilla/Attributes.h"
26 #include "mozilla/Assertions.h"
27 #include "mozilla/Likely.h"
28 #include "mozilla/MacroArgs.h"
29 #include "mozilla/MacroForEach.h"
30
31 inline nsISupports*
32 ToSupports(nsISupports* p)
33 {
34 return p;
35 }
36
37 inline nsISupports*
38 ToCanonicalSupports(nsISupports* p)
39 {
40 return nullptr;
41 }
42
43 ////////////////////////////////////////////////////////////////////////////////
44 // Macros to help detect thread-safety:
45
46 #if (defined(DEBUG) || (defined(NIGHTLY_BUILD) && !defined(MOZ_PROFILING))) && !defined(XPCOM_GLUE_AVOID_NSPR)
47
48 class nsAutoOwningThread {
49 public:
50 nsAutoOwningThread() { mThread = PR_GetCurrentThread(); }
51 void *GetThread() const { return mThread; }
52
53 private:
54 void *mThread;
55 };
56
57 #define NS_DECL_OWNINGTHREAD nsAutoOwningThread _mOwningThread;
58 #define NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class) \
59 NS_CheckThreadSafe(agg->_mOwningThread.GetThread(), #_class " not thread-safe")
60 #define NS_ASSERT_OWNINGTHREAD(_class) NS_ASSERT_OWNINGTHREAD_AGGREGATE(this, _class)
61 #else // !DEBUG && !(NIGHTLY_BUILD && !MOZ_PROFILING)
62
63 #define NS_DECL_OWNINGTHREAD /* nothing */
64 #define NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class) ((void)0)
65 #define NS_ASSERT_OWNINGTHREAD(_class) ((void)0)
66
67 #endif // DEBUG || (NIGHTLY_BUILD && !MOZ_PROFILING)
68
69
70 // Macros for reference-count and constructor logging
71
72 #ifdef NS_BUILD_REFCNT_LOGGING
73
74 #define NS_LOG_ADDREF(_p, _rc, _type, _size) \
75 NS_LogAddRef((_p), (_rc), (_type), (uint32_t) (_size))
76
77 #define NS_LOG_RELEASE(_p, _rc, _type) \
78 NS_LogRelease((_p), (_rc), (_type))
79
80 // Note that the following constructor/destructor logging macros are redundant
81 // for refcounted objects that log via the NS_LOG_ADDREF/NS_LOG_RELEASE macros.
82 // Refcount logging is preferred.
83 #define MOZ_COUNT_CTOR(_type) \
84 do { \
85 NS_LogCtor((void*)this, #_type, sizeof(*this)); \
86 } while (0)
87
88 #define MOZ_COUNT_CTOR_INHERITED(_type, _base) \
89 do { \
90 NS_LogCtor((void*)this, #_type, sizeof(*this) - sizeof(_base)); \
91 } while (0)
92
93 #define MOZ_COUNT_DTOR(_type) \
94 do { \
95 NS_LogDtor((void*)this, #_type, sizeof(*this)); \
96 } while (0)
97
98 #define MOZ_COUNT_DTOR_INHERITED(_type, _base) \
99 do { \
100 NS_LogDtor((void*)this, #_type, sizeof(*this) - sizeof(_base)); \
101 } while (0)
102
103 /* nsCOMPtr.h allows these macros to be defined by clients
104 * These logging functions require dynamic_cast<void*>, so they don't
105 * do anything useful if we don't have dynamic_cast<void*>. */
106 #define NSCAP_LOG_ASSIGNMENT(_c, _p) \
107 if (_p) \
108 NS_LogCOMPtrAddRef((_c),static_cast<nsISupports*>(_p))
109
110 #define NSCAP_LOG_RELEASE(_c, _p) \
111 if (_p) \
112 NS_LogCOMPtrRelease((_c), static_cast<nsISupports*>(_p))
113
114 #else /* !NS_BUILD_REFCNT_LOGGING */
115
116 #define NS_LOG_ADDREF(_p, _rc, _type, _size)
117 #define NS_LOG_RELEASE(_p, _rc, _type)
118 #define MOZ_COUNT_CTOR(_type)
119 #define MOZ_COUNT_CTOR_INHERITED(_type, _base)
120 #define MOZ_COUNT_DTOR(_type)
121 #define MOZ_COUNT_DTOR_INHERITED(_type, _base)
122
123 #endif /* NS_BUILD_REFCNT_LOGGING */
124
125
126 // Support for ISupports classes which interact with cycle collector.
127
128 #define NS_NUMBER_OF_FLAGS_IN_REFCNT 2
129 #define NS_IN_PURPLE_BUFFER (1 << 0)
130 #define NS_IS_PURPLE (1 << 1)
131 #define NS_REFCOUNT_CHANGE (1 << NS_NUMBER_OF_FLAGS_IN_REFCNT)
132 #define NS_REFCOUNT_VALUE(_val) (_val >> NS_NUMBER_OF_FLAGS_IN_REFCNT)
133
134 class nsCycleCollectingAutoRefCnt {
135
136 public:
137 nsCycleCollectingAutoRefCnt()
138 : mRefCntAndFlags(0)
139 {}
140
141 nsCycleCollectingAutoRefCnt(uintptr_t aValue)
142 : mRefCntAndFlags(aValue << NS_NUMBER_OF_FLAGS_IN_REFCNT)
143 {
144 }
145
146 MOZ_ALWAYS_INLINE uintptr_t incr(nsISupports *owner)
147 {
148 return incr(owner, nullptr);
149 }
150
151 MOZ_ALWAYS_INLINE uintptr_t incr(void *owner, nsCycleCollectionParticipant *p)
152 {
153 mRefCntAndFlags += NS_REFCOUNT_CHANGE;
154 mRefCntAndFlags &= ~NS_IS_PURPLE;
155 // For incremental cycle collection, use the purple buffer to track objects
156 // that have been AddRef'd.
157 if (!IsInPurpleBuffer()) {
158 mRefCntAndFlags |= NS_IN_PURPLE_BUFFER;
159 // Refcount isn't zero, so Suspect won't delete anything.
160 MOZ_ASSERT(get() > 0);
161 NS_CycleCollectorSuspect3(owner, p, this, nullptr);
162 }
163 return NS_REFCOUNT_VALUE(mRefCntAndFlags);
164 }
165
166 MOZ_ALWAYS_INLINE void stabilizeForDeletion()
167 {
168 // Set refcnt to 1 and mark us to be in the purple buffer.
169 // This way decr won't call suspect again.
170 mRefCntAndFlags = NS_REFCOUNT_CHANGE | NS_IN_PURPLE_BUFFER;
171 }
172
173 MOZ_ALWAYS_INLINE uintptr_t decr(nsISupports *owner,
174 bool *shouldDelete = nullptr)
175 {
176 return decr(owner, nullptr, shouldDelete);
177 }
178
179 MOZ_ALWAYS_INLINE uintptr_t decr(void *owner, nsCycleCollectionParticipant *p,
180 bool *shouldDelete = nullptr)
181 {
182 MOZ_ASSERT(get() > 0);
183 if (!IsInPurpleBuffer()) {
184 mRefCntAndFlags -= NS_REFCOUNT_CHANGE;
185 mRefCntAndFlags |= (NS_IN_PURPLE_BUFFER | NS_IS_PURPLE);
186 uintptr_t retval = NS_REFCOUNT_VALUE(mRefCntAndFlags);
187 // Suspect may delete 'owner' and 'this'!
188 NS_CycleCollectorSuspect3(owner, p, this, shouldDelete);
189 return retval;
190 }
191 mRefCntAndFlags -= NS_REFCOUNT_CHANGE;
192 mRefCntAndFlags |= (NS_IN_PURPLE_BUFFER | NS_IS_PURPLE);
193 return NS_REFCOUNT_VALUE(mRefCntAndFlags);
194 }
195
196 MOZ_ALWAYS_INLINE void RemovePurple()
197 {
198 MOZ_ASSERT(IsPurple(), "must be purple");
199 mRefCntAndFlags &= ~NS_IS_PURPLE;
200 }
201
202 MOZ_ALWAYS_INLINE void RemoveFromPurpleBuffer()
203 {
204 MOZ_ASSERT(IsInPurpleBuffer());
205 mRefCntAndFlags &= ~(NS_IS_PURPLE | NS_IN_PURPLE_BUFFER);
206 }
207
208 MOZ_ALWAYS_INLINE bool IsPurple() const
209 {
210 return !!(mRefCntAndFlags & NS_IS_PURPLE);
211 }
212
213 MOZ_ALWAYS_INLINE bool IsInPurpleBuffer() const
214 {
215 return !!(mRefCntAndFlags & NS_IN_PURPLE_BUFFER);
216 }
217
218 MOZ_ALWAYS_INLINE nsrefcnt get() const
219 {
220 return NS_REFCOUNT_VALUE(mRefCntAndFlags);
221 }
222
223 MOZ_ALWAYS_INLINE operator nsrefcnt() const
224 {
225 return get();
226 }
227
228 private:
229 uintptr_t mRefCntAndFlags;
230 };
231
232 class nsAutoRefCnt {
233
234 public:
235 nsAutoRefCnt() : mValue(0) {}
236 nsAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {}
237
238 // only support prefix increment/decrement
239 nsrefcnt operator++() { return ++mValue; }
240 nsrefcnt operator--() { return --mValue; }
241
242 nsrefcnt operator=(nsrefcnt aValue) { return (mValue = aValue); }
243 operator nsrefcnt() const { return mValue; }
244 nsrefcnt get() const { return mValue; }
245
246 static const bool isThreadSafe = false;
247 private:
248 nsrefcnt operator++(int) MOZ_DELETE;
249 nsrefcnt operator--(int) MOZ_DELETE;
250 nsrefcnt mValue;
251 };
252
253 #ifndef XPCOM_GLUE
254 namespace mozilla {
255 class ThreadSafeAutoRefCnt {
256 public:
257 ThreadSafeAutoRefCnt() : mValue(0) {}
258 ThreadSafeAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {}
259
260 // only support prefix increment/decrement
261 MOZ_ALWAYS_INLINE nsrefcnt operator++() { return ++mValue; }
262 MOZ_ALWAYS_INLINE nsrefcnt operator--() { return --mValue; }
263
264 MOZ_ALWAYS_INLINE nsrefcnt operator=(nsrefcnt aValue) { return (mValue = aValue); }
265 MOZ_ALWAYS_INLINE operator nsrefcnt() const { return mValue; }
266 MOZ_ALWAYS_INLINE nsrefcnt get() const { return mValue; }
267
268 static const bool isThreadSafe = true;
269 private:
270 nsrefcnt operator++(int) MOZ_DELETE;
271 nsrefcnt operator--(int) MOZ_DELETE;
272 // In theory, RelaseAcquire consistency (but no weaker) is sufficient for
273 // the counter. Making it weaker could speed up builds on ARM (but not x86),
274 // but could break pre-existing code that assumes sequential consistency.
275 Atomic<nsrefcnt> mValue;
276 };
277 }
278 #endif
279
280 ///////////////////////////////////////////////////////////////////////////////
281
282 /**
283 * Declare the reference count variable and the implementations of the
284 * AddRef and QueryInterface methods.
285 */
286
287 #define NS_DECL_ISUPPORTS \
288 public: \
289 NS_IMETHOD QueryInterface(REFNSIID aIID, \
290 void** aInstancePtr); \
291 NS_IMETHOD_(MozExternalRefCountType) AddRef(void); \
292 NS_IMETHOD_(MozExternalRefCountType) Release(void); \
293 protected: \
294 nsAutoRefCnt mRefCnt; \
295 NS_DECL_OWNINGTHREAD \
296 public:
297
298 #define NS_DECL_THREADSAFE_ISUPPORTS \
299 public: \
300 NS_IMETHOD QueryInterface(REFNSIID aIID, \
301 void** aInstancePtr); \
302 NS_IMETHOD_(MozExternalRefCountType) AddRef(void); \
303 NS_IMETHOD_(MozExternalRefCountType) Release(void); \
304 protected: \
305 ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \
306 NS_DECL_OWNINGTHREAD \
307 public:
308
309 #define NS_DECL_CYCLE_COLLECTING_ISUPPORTS \
310 public: \
311 NS_IMETHOD QueryInterface(REFNSIID aIID, \
312 void** aInstancePtr); \
313 NS_IMETHOD_(MozExternalRefCountType) AddRef(void); \
314 NS_IMETHOD_(MozExternalRefCountType) Release(void); \
315 NS_IMETHOD_(void) DeleteCycleCollectable(void); \
316 protected: \
317 nsCycleCollectingAutoRefCnt mRefCnt; \
318 NS_DECL_OWNINGTHREAD \
319 public:
320
321
322 ///////////////////////////////////////////////////////////////////////////////
323
324 /*
325 * Implementation of AddRef and Release for non-nsISupports (ie "native")
326 * cycle-collected classes that use the purple buffer to avoid leaks.
327 */
328
329 #define NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \
330 MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \
331 NS_ASSERT_OWNINGTHREAD(_class); \
332 nsrefcnt count = \
333 mRefCnt.incr(static_cast<void*>(this), \
334 _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \
335 NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \
336 return count;
337
338 #define NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \
339 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
340 NS_ASSERT_OWNINGTHREAD(_class); \
341 nsrefcnt count = \
342 mRefCnt.decr(static_cast<void*>(this), \
343 _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \
344 NS_LOG_RELEASE(this, count, #_class); \
345 return count;
346
347 #define NS_IMPL_CYCLE_COLLECTING_NATIVE_ADDREF(_class) \
348 NS_METHOD_(MozExternalRefCountType) _class::AddRef(void) \
349 { \
350 NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \
351 }
352
353 #define NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE_WITH_LAST_RELEASE(_class, _last) \
354 NS_METHOD_(MozExternalRefCountType) _class::Release(void) \
355 { \
356 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
357 NS_ASSERT_OWNINGTHREAD(_class); \
358 bool shouldDelete = false; \
359 nsrefcnt count = \
360 mRefCnt.decr(static_cast<void*>(this), \
361 _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant(), \
362 &shouldDelete); \
363 NS_LOG_RELEASE(this, count, #_class); \
364 if (count == 0) { \
365 mRefCnt.incr(static_cast<void*>(this), \
366 _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \
367 _last; \
368 mRefCnt.decr(static_cast<void*>(this), \
369 _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \
370 if (shouldDelete) { \
371 mRefCnt.stabilizeForDeletion(); \
372 DeleteCycleCollectable(); \
373 } \
374 } \
375 return count; \
376 }
377
378 #define NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE(_class) \
379 NS_METHOD_(MozExternalRefCountType) _class::Release(void) \
380 { \
381 NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \
382 }
383
384 #define NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(_class) \
385 public: \
386 NS_METHOD_(MozExternalRefCountType) AddRef(void) { \
387 NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \
388 } \
389 NS_METHOD_(MozExternalRefCountType) Release(void) { \
390 NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \
391 } \
392 protected: \
393 nsCycleCollectingAutoRefCnt mRefCnt; \
394 NS_DECL_OWNINGTHREAD \
395 public:
396
397
398 ///////////////////////////////////////////////////////////////////////////////
399
400 /**
401 * Previously used to initialize the reference count, but no longer needed.
402 *
403 * DEPRECATED.
404 */
405 #define NS_INIT_ISUPPORTS() ((void)0)
406
407 /**
408 * Use this macro to declare and implement the AddRef & Release methods for a
409 * given non-XPCOM <i>_class</i>.
410 *
411 * @param _class The name of the class implementing the method
412 */
413 #define NS_INLINE_DECL_REFCOUNTING(_class) \
414 public: \
415 NS_METHOD_(MozExternalRefCountType) AddRef(void) { \
416 MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \
417 NS_ASSERT_OWNINGTHREAD(_class); \
418 ++mRefCnt; \
419 NS_LOG_ADDREF(this, mRefCnt, #_class, sizeof(*this)); \
420 return mRefCnt; \
421 } \
422 NS_METHOD_(MozExternalRefCountType) Release(void) { \
423 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
424 NS_ASSERT_OWNINGTHREAD(_class); \
425 --mRefCnt; \
426 NS_LOG_RELEASE(this, mRefCnt, #_class); \
427 if (mRefCnt == 0) { \
428 NS_ASSERT_OWNINGTHREAD(_class); \
429 mRefCnt = 1; /* stabilize */ \
430 delete this; \
431 return 0; \
432 } \
433 return mRefCnt; \
434 } \
435 protected: \
436 nsAutoRefCnt mRefCnt; \
437 NS_DECL_OWNINGTHREAD \
438 public:
439
440 /**
441 * Use this macro to declare and implement the AddRef & Release methods for a
442 * given non-XPCOM <i>_class</i> in a threadsafe manner.
443 *
444 * DOES NOT DO REFCOUNT STABILIZATION!
445 *
446 * @param _class The name of the class implementing the method
447 */
448 #define NS_INLINE_DECL_THREADSAFE_REFCOUNTING(_class) \
449 public: \
450 NS_METHOD_(MozExternalRefCountType) AddRef(void) { \
451 MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \
452 nsrefcnt count = ++mRefCnt; \
453 NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \
454 return (nsrefcnt) count; \
455 } \
456 NS_METHOD_(MozExternalRefCountType) Release(void) { \
457 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
458 nsrefcnt count = --mRefCnt; \
459 NS_LOG_RELEASE(this, count, #_class); \
460 if (count == 0) { \
461 delete (this); \
462 return 0; \
463 } \
464 return count; \
465 } \
466 protected: \
467 ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \
468 public:
469
470 /**
471 * Use this macro to implement the AddRef method for a given <i>_class</i>
472 * @param _class The name of the class implementing the method
473 */
474 #define NS_IMPL_ADDREF(_class) \
475 NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \
476 { \
477 MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \
478 if (!mRefCnt.isThreadSafe) \
479 NS_ASSERT_OWNINGTHREAD(_class); \
480 nsrefcnt count = ++mRefCnt; \
481 NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \
482 return count; \
483 }
484
485 /**
486 * Use this macro to implement the AddRef method for a given <i>_class</i>
487 * implemented as a wholly owned aggregated object intended to implement
488 * interface(s) for its owner
489 * @param _class The name of the class implementing the method
490 * @param _aggregator the owning/containing object
491 */
492 #define NS_IMPL_ADDREF_USING_AGGREGATOR(_class, _aggregator) \
493 NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \
494 { \
495 NS_PRECONDITION(_aggregator, "null aggregator"); \
496 return (_aggregator)->AddRef(); \
497 }
498
499 /**
500 * Use this macro to implement the Release method for a given
501 * <i>_class</i>.
502 * @param _class The name of the class implementing the method
503 * @param _destroy A statement that is executed when the object's
504 * refcount drops to zero.
505 *
506 * For example,
507 *
508 * NS_IMPL_RELEASE_WITH_DESTROY(Foo, Destroy(this))
509 *
510 * will cause
511 *
512 * Destroy(this);
513 *
514 * to be invoked when the object's refcount drops to zero. This
515 * allows for arbitrary teardown activity to occur (e.g., deallocation
516 * of object allocated with placement new).
517 */
518 #define NS_IMPL_RELEASE_WITH_DESTROY(_class, _destroy) \
519 NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \
520 { \
521 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
522 if (!mRefCnt.isThreadSafe) \
523 NS_ASSERT_OWNINGTHREAD(_class); \
524 nsrefcnt count = --mRefCnt; \
525 NS_LOG_RELEASE(this, count, #_class); \
526 if (count == 0) { \
527 if (!mRefCnt.isThreadSafe) \
528 NS_ASSERT_OWNINGTHREAD(_class); \
529 mRefCnt = 1; /* stabilize */ \
530 _destroy; \
531 return 0; \
532 } \
533 return count; \
534 }
535
536 /**
537 * Use this macro to implement the Release method for a given <i>_class</i>
538 * @param _class The name of the class implementing the method
539 *
540 * A note on the 'stabilization' of the refcnt to one. At that point,
541 * the object's refcount will have gone to zero. The object's
542 * destructor may trigger code that attempts to QueryInterface() and
543 * Release() 'this' again. Doing so will temporarily increment and
544 * decrement the refcount. (Only a logic error would make one try to
545 * keep a permanent hold on 'this'.) To prevent re-entering the
546 * destructor, we make sure that no balanced refcounting can return
547 * the refcount to |0|.
548 */
549 #define NS_IMPL_RELEASE(_class) \
550 NS_IMPL_RELEASE_WITH_DESTROY(_class, delete (this))
551
552 /**
553 * Use this macro to implement the Release method for a given <i>_class</i>
554 * implemented as a wholly owned aggregated object intended to implement
555 * interface(s) for its owner
556 * @param _class The name of the class implementing the method
557 * @param _aggregator the owning/containing object
558 */
559 #define NS_IMPL_RELEASE_USING_AGGREGATOR(_class, _aggregator) \
560 NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \
561 { \
562 NS_PRECONDITION(_aggregator, "null aggregator"); \
563 return (_aggregator)->Release(); \
564 }
565
566
567 #define NS_IMPL_CYCLE_COLLECTING_ADDREF(_class) \
568 NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \
569 { \
570 MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \
571 NS_ASSERT_OWNINGTHREAD(_class); \
572 nsISupports *base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \
573 nsrefcnt count = mRefCnt.incr(base); \
574 NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \
575 return count; \
576 }
577
578 #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(_class, _destroy) \
579 NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \
580 { \
581 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
582 NS_ASSERT_OWNINGTHREAD(_class); \
583 nsISupports *base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \
584 nsrefcnt count = mRefCnt.decr(base); \
585 NS_LOG_RELEASE(this, count, #_class); \
586 return count; \
587 } \
588 NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) \
589 { \
590 _destroy; \
591 }
592
593 #define NS_IMPL_CYCLE_COLLECTING_RELEASE(_class) \
594 NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(_class, delete (this))
595
596 // _LAST_RELEASE can be useful when certain resources should be released
597 // as soon as we know the object will be deleted.
598 #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE(_class, _last) \
599 NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \
600 { \
601 MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \
602 NS_ASSERT_OWNINGTHREAD(_class); \
603 bool shouldDelete = false; \
604 nsISupports *base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \
605 nsrefcnt count = mRefCnt.decr(base, &shouldDelete); \
606 NS_LOG_RELEASE(this, count, #_class); \
607 if (count == 0) { \
608 mRefCnt.incr(base); \
609 _last; \
610 mRefCnt.decr(base); \
611 if (shouldDelete) { \
612 mRefCnt.stabilizeForDeletion(); \
613 DeleteCycleCollectable(); \
614 } \
615 } \
616 return count; \
617 } \
618 NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) \
619 { \
620 delete this; \
621 }
622
623 ///////////////////////////////////////////////////////////////////////////////
624
625 /**
626 * There are two ways of implementing QueryInterface, and we use both:
627 *
628 * Table-driven QueryInterface uses a static table of IID->offset mappings
629 * and a shared helper function. Using it tends to reduce codesize and improve
630 * runtime performance (due to processor cache hits).
631 *
632 * Macro-driven QueryInterface generates a QueryInterface function directly
633 * using common macros. This is necessary if special QueryInterface features
634 * are being used (such as tearoffs and conditional interfaces).
635 *
636 * These methods can be combined into a table-driven function call followed
637 * by custom code for tearoffs and conditionals.
638 */
639
640 struct QITableEntry
641 {
642 const nsIID *iid; // null indicates end of the QITableEntry array
643 int32_t offset;
644 };
645
646 NS_COM_GLUE nsresult NS_FASTCALL
647 NS_TableDrivenQI(void* aThis, REFNSIID aIID,
648 void **aInstancePtr, const QITableEntry* entries);
649
650 /**
651 * Implement table-driven queryinterface
652 */
653
654 #define NS_INTERFACE_TABLE_HEAD(_class) \
655 NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) \
656 { \
657 NS_ASSERTION(aInstancePtr, \
658 "QueryInterface requires a non-NULL destination!"); \
659 nsresult rv = NS_ERROR_FAILURE;
660
661 #define NS_INTERFACE_TABLE_BEGIN \
662 static const QITableEntry table[] = {
663
664 #define NS_INTERFACE_TABLE_ENTRY(_class, _interface) \
665 { &_interface::COMTypeInfo<int>::kIID, \
666 int32_t(reinterpret_cast<char*>( \
667 static_cast<_interface*>((_class*) 0x1000)) - \
668 reinterpret_cast<char*>((_class*) 0x1000)) \
669 },
670
671 #define NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(_class, _interface, _implClass) \
672 { &_interface::COMTypeInfo<int>::kIID, \
673 int32_t(reinterpret_cast<char*>( \
674 static_cast<_interface*>( \
675 static_cast<_implClass*>( \
676 (_class*) 0x1000))) - \
677 reinterpret_cast<char*>((_class*) 0x1000)) \
678 },
679
680 /*
681 * XXX: we want to use mozilla::ArrayLength (or equivalent,
682 * MOZ_ARRAY_LENGTH) in this condition, but some versions of GCC don't
683 * see that the static_assert condition is actually constant in those
684 * cases, even with constexpr support (?).
685 */
686 #define NS_INTERFACE_TABLE_END_WITH_PTR(_ptr) \
687 { nullptr, 0 } }; \
688 static_assert((sizeof(table)/sizeof(table[0])) > 1, "need at least 1 interface"); \
689 rv = NS_TableDrivenQI(static_cast<void*>(_ptr), \
690 aIID, aInstancePtr, table);
691
692 #define NS_INTERFACE_TABLE_END \
693 NS_INTERFACE_TABLE_END_WITH_PTR(this)
694
695 #define NS_INTERFACE_TABLE_TAIL \
696 return rv; \
697 }
698
699 #define NS_INTERFACE_TABLE_TAIL_INHERITING(_baseclass) \
700 if (NS_SUCCEEDED(rv)) \
701 return rv; \
702 return _baseclass::QueryInterface(aIID, aInstancePtr); \
703 }
704
705 #define NS_INTERFACE_TABLE_TAIL_USING_AGGREGATOR(_aggregator) \
706 if (NS_SUCCEEDED(rv)) \
707 return rv; \
708 NS_ASSERTION(_aggregator, "null aggregator"); \
709 return _aggregator->QueryInterface(aIID, aInstancePtr) \
710 }
711
712 /**
713 * This implements query interface with two assumptions: First, the
714 * class in question implements nsISupports and its own interface and
715 * nothing else. Second, the implementation of the class's primary
716 * inheritance chain leads to its own interface.
717 *
718 * @param _class The name of the class implementing the method
719 * @param _classiiddef The name of the #define symbol that defines the IID
720 * for the class (e.g. NS_ISUPPORTS_IID)
721 */
722
723 #define NS_IMPL_QUERY_HEAD(_class) \
724 NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) \
725 { \
726 NS_ASSERTION(aInstancePtr, \
727 "QueryInterface requires a non-NULL destination!"); \
728 nsISupports* foundInterface;
729
730 #define NS_IMPL_QUERY_BODY(_interface) \
731 if ( aIID.Equals(NS_GET_IID(_interface)) ) \
732 foundInterface = static_cast<_interface*>(this); \
733 else
734
735 #define NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition) \
736 if ( (condition) && aIID.Equals(NS_GET_IID(_interface))) \
737 foundInterface = static_cast<_interface*>(this); \
738 else
739
740 #define NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass) \
741 if ( aIID.Equals(NS_GET_IID(_interface)) ) \
742 foundInterface = static_cast<_interface*>( \
743 static_cast<_implClass*>(this)); \
744 else
745
746 #define NS_IMPL_QUERY_BODY_AGGREGATED(_interface, _aggregate) \
747 if ( aIID.Equals(NS_GET_IID(_interface)) ) \
748 foundInterface = static_cast<_interface*>(_aggregate); \
749 else
750
751 #define NS_IMPL_QUERY_TAIL_GUTS \
752 foundInterface = 0; \
753 nsresult status; \
754 if ( !foundInterface ) \
755 { \
756 /* nsISupports should be handled by this point. If not, fail. */ \
757 MOZ_ASSERT(!aIID.Equals(NS_GET_IID(nsISupports))); \
758 status = NS_NOINTERFACE; \
759 } \
760 else \
761 { \
762 NS_ADDREF(foundInterface); \
763 status = NS_OK; \
764 } \
765 *aInstancePtr = foundInterface; \
766 return status; \
767 }
768
769 #define NS_IMPL_QUERY_TAIL_INHERITING(_baseclass) \
770 foundInterface = 0; \
771 nsresult status; \
772 if ( !foundInterface ) \
773 status = _baseclass::QueryInterface(aIID, (void**)&foundInterface); \
774 else \
775 { \
776 NS_ADDREF(foundInterface); \
777 status = NS_OK; \
778 } \
779 *aInstancePtr = foundInterface; \
780 return status; \
781 }
782
783 #define NS_IMPL_QUERY_TAIL_USING_AGGREGATOR(_aggregator) \
784 foundInterface = 0; \
785 nsresult status; \
786 if ( !foundInterface ) { \
787 NS_ASSERTION(_aggregator, "null aggregator"); \
788 status = _aggregator->QueryInterface(aIID, (void**)&foundInterface); \
789 } else \
790 { \
791 NS_ADDREF(foundInterface); \
792 status = NS_OK; \
793 } \
794 *aInstancePtr = foundInterface; \
795 return status; \
796 }
797
798 #define NS_IMPL_QUERY_TAIL(_supports_interface) \
799 NS_IMPL_QUERY_BODY_AMBIGUOUS(nsISupports, _supports_interface) \
800 NS_IMPL_QUERY_TAIL_GUTS
801
802
803 /*
804 This is the new scheme. Using this notation now will allow us to switch to
805 a table driven mechanism when it's ready. Note the difference between this
806 and the (currently) underlying NS_IMPL_QUERY_INTERFACE mechanism. You must
807 explicitly mention |nsISupports| when using the interface maps.
808 */
809 #define NS_INTERFACE_MAP_BEGIN(_implClass) NS_IMPL_QUERY_HEAD(_implClass)
810 #define NS_INTERFACE_MAP_ENTRY(_interface) NS_IMPL_QUERY_BODY(_interface)
811 #define NS_INTERFACE_MAP_ENTRY_CONDITIONAL(_interface, condition) \
812 NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition)
813 #define NS_INTERFACE_MAP_ENTRY_AGGREGATED(_interface,_aggregate) \
814 NS_IMPL_QUERY_BODY_AGGREGATED(_interface,_aggregate)
815
816 #define NS_INTERFACE_MAP_END NS_IMPL_QUERY_TAIL_GUTS
817 #define NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(_interface, _implClass) \
818 NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass)
819 #define NS_INTERFACE_MAP_END_INHERITING(_baseClass) \
820 NS_IMPL_QUERY_TAIL_INHERITING(_baseClass)
821 #define NS_INTERFACE_MAP_END_AGGREGATED(_aggregator) \
822 NS_IMPL_QUERY_TAIL_USING_AGGREGATOR(_aggregator)
823
824 #define NS_INTERFACE_TABLE0(_class) \
825 NS_INTERFACE_TABLE_BEGIN \
826 NS_INTERFACE_TABLE_ENTRY(_class, nsISupports) \
827 NS_INTERFACE_TABLE_END
828
829 #define NS_INTERFACE_TABLE(aClass, ...) \
830 MOZ_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__); \
831 NS_INTERFACE_TABLE_BEGIN \
832 MOZ_FOR_EACH(NS_INTERFACE_TABLE_ENTRY, (aClass,), (__VA_ARGS__)) \
833 NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(aClass, nsISupports, \
834 MOZ_ARG_1(__VA_ARGS__)) \
835 NS_INTERFACE_TABLE_END
836
837 #define NS_IMPL_QUERY_INTERFACE0(_class) \
838 NS_INTERFACE_TABLE_HEAD(_class) \
839 NS_INTERFACE_TABLE0(_class) \
840 NS_INTERFACE_TABLE_TAIL
841
842 #define NS_IMPL_QUERY_INTERFACE(aClass, ...) \
843 NS_INTERFACE_TABLE_HEAD(aClass) \
844 NS_INTERFACE_TABLE(aClass, __VA_ARGS__) \
845 NS_INTERFACE_TABLE_TAIL
846
847 /**
848 * Declare that you're going to inherit from something that already
849 * implements nsISupports, but also implements an additional interface, thus
850 * causing an ambiguity. In this case you don't need another mRefCnt, you
851 * just need to forward the definitions to the appropriate superclass. E.g.
852 *
853 * class Bar : public Foo, public nsIBar { // both provide nsISupports
854 * public:
855 * NS_DECL_ISUPPORTS_INHERITED
856 * ...other nsIBar and Bar methods...
857 * };
858 */
859 #define NS_DECL_ISUPPORTS_INHERITED \
860 public: \
861 NS_IMETHOD QueryInterface(REFNSIID aIID, \
862 void** aInstancePtr); \
863 NS_IMETHOD_(MozExternalRefCountType) AddRef(void); \
864 NS_IMETHOD_(MozExternalRefCountType) Release(void); \
865
866 /**
867 * These macros can be used in conjunction with NS_DECL_ISUPPORTS_INHERITED
868 * to implement the nsISupports methods, forwarding the invocations to a
869 * superclass that already implements nsISupports.
870 *
871 * Note that I didn't make these inlined because they're virtual methods.
872 */
873
874 #define NS_IMPL_ADDREF_INHERITED(Class, Super) \
875 NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) \
876 { \
877 nsrefcnt r = Super::AddRef(); \
878 NS_LOG_ADDREF(this, r, #Class, sizeof(*this)); \
879 return r; \
880 }
881
882 #define NS_IMPL_RELEASE_INHERITED(Class, Super) \
883 NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) \
884 { \
885 nsrefcnt r = Super::Release(); \
886 NS_LOG_RELEASE(this, r, #Class); \
887 return r; \
888 }
889
890 /**
891 * As above but not logging the addref/release; needed if the base
892 * class might be aggregated.
893 */
894 #define NS_IMPL_NONLOGGING_ADDREF_INHERITED(Class, Super) \
895 NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) \
896 { \
897 return Super::AddRef(); \
898 }
899
900 #define NS_IMPL_NONLOGGING_RELEASE_INHERITED(Class, Super) \
901 NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) \
902 { \
903 return Super::Release(); \
904 }
905
906 #define NS_INTERFACE_TABLE_INHERITED0(Class) /* Nothing to do here */
907
908 #define NS_INTERFACE_TABLE_INHERITED(aClass, ...) \
909 MOZ_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__); \
910 NS_INTERFACE_TABLE_BEGIN \
911 MOZ_FOR_EACH(NS_INTERFACE_TABLE_ENTRY, (aClass,), (__VA_ARGS__)) \
912 NS_INTERFACE_TABLE_END
913
914 #define NS_IMPL_QUERY_INTERFACE_INHERITED0(aClass, aSuper) \
915 NS_INTERFACE_TABLE_HEAD(aClass) \
916 NS_INTERFACE_TABLE_INHERITED0(aClass) \
917 NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper)
918
919 #define NS_IMPL_QUERY_INTERFACE_INHERITED(aClass, aSuper, ...) \
920 NS_INTERFACE_TABLE_HEAD(aClass) \
921 NS_INTERFACE_TABLE_INHERITED(aClass, __VA_ARGS__) \
922 NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper)
923
924 /**
925 * Convenience macros for implementing all nsISupports methods for
926 * a simple class.
927 * @param _class The name of the class implementing the method
928 * @param _classiiddef The name of the #define symbol that defines the IID
929 * for the class (e.g. NS_ISUPPORTS_IID)
930 */
931
932 #define NS_IMPL_ISUPPORTS0(_class) \
933 NS_IMPL_ADDREF(_class) \
934 NS_IMPL_RELEASE(_class) \
935 NS_IMPL_QUERY_INTERFACE0(_class)
936
937 #define NS_IMPL_ISUPPORTS(aClass, ...) \
938 NS_IMPL_ADDREF(aClass) \
939 NS_IMPL_RELEASE(aClass) \
940 NS_IMPL_QUERY_INTERFACE(aClass, __VA_ARGS__)
941
942 #define NS_IMPL_ISUPPORTS_INHERITED0(aClass, aSuper) \
943 NS_IMPL_QUERY_INTERFACE_INHERITED0(aClass, aSuper) \
944 NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \
945 NS_IMPL_RELEASE_INHERITED(aClass, aSuper) \
946
947 #define NS_IMPL_ISUPPORTS_INHERITED(aClass, aSuper, ...) \
948 NS_IMPL_QUERY_INTERFACE_INHERITED(aClass, aSuper, __VA_ARGS__) \
949 NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \
950 NS_IMPL_RELEASE_INHERITED(aClass, aSuper)
951
952 /*
953 * Macro to glue together a QI that starts with an interface table
954 * and segues into an interface map (e.g. it uses singleton classinfo
955 * or tearoffs).
956 */
957 #define NS_INTERFACE_TABLE_TO_MAP_SEGUE \
958 if (rv == NS_OK) return rv; \
959 nsISupports* foundInterface;
960
961
962 ///////////////////////////////////////////////////////////////////////////////
963 /**
964 *
965 * Threadsafe implementations of the ISupports convenience macros.
966 *
967 * @note These are not available when linking against the standalone glue,
968 * because the implementation requires PR_ symbols.
969 */
970 #define NS_INTERFACE_MAP_END_THREADSAFE NS_IMPL_QUERY_TAIL_GUTS
971
972 /**
973 * Macro to generate nsIClassInfo methods for classes which do not have
974 * corresponding nsIFactory implementations.
975 */
976 #define NS_IMPL_THREADSAFE_CI(_class) \
977 NS_IMETHODIMP \
978 _class::GetInterfaces(uint32_t* _count, nsIID*** _array) \
979 { \
980 return NS_CI_INTERFACE_GETTER_NAME(_class)(_count, _array); \
981 } \
982 \
983 NS_IMETHODIMP \
984 _class::GetHelperForLanguage(uint32_t _language, nsISupports** _retval) \
985 { \
986 *_retval = nullptr; \
987 return NS_OK; \
988 } \
989 \
990 NS_IMETHODIMP \
991 _class::GetContractID(char** _contractID) \
992 { \
993 *_contractID = nullptr; \
994 return NS_OK; \
995 } \
996 \
997 NS_IMETHODIMP \
998 _class::GetClassDescription(char** _classDescription) \
999 { \
1000 *_classDescription = nullptr; \
1001 return NS_OK; \
1002 } \
1003 \
1004 NS_IMETHODIMP \
1005 _class::GetClassID(nsCID** _classID) \
1006 { \
1007 *_classID = nullptr; \
1008 return NS_OK; \
1009 } \
1010 \
1011 NS_IMETHODIMP \
1012 _class::GetImplementationLanguage(uint32_t* _language) \
1013 { \
1014 *_language = nsIProgrammingLanguage::CPLUSPLUS; \
1015 return NS_OK; \
1016 } \
1017 \
1018 NS_IMETHODIMP \
1019 _class::GetFlags(uint32_t* _flags) \
1020 { \
1021 *_flags = nsIClassInfo::THREADSAFE; \
1022 return NS_OK; \
1023 } \
1024 \
1025 NS_IMETHODIMP \
1026 _class::GetClassIDNoAlloc(nsCID* _classIDNoAlloc) \
1027 { \
1028 return NS_ERROR_NOT_AVAILABLE; \
1029 }
1030
1031 #endif

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