/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ // IWYU pragma: private, include "nsISupports.h" #ifndef nsISupportsImpl_h__ #define nsISupportsImpl_h__ #include "nscore.h" #include "nsISupports.h" #include "nsISupportsUtils.h" #if !defined(XPCOM_GLUE_AVOID_NSPR) # include "prthread.h" /* needed for cargo-culting headers */ #endif #include "nsDebug.h" #include "nsXPCOM.h" #include #include #include "mozilla/Attributes.h" #include "mozilla/Assertions.h" #include "mozilla/Atomics.h" #include "mozilla/Compiler.h" #include "mozilla/Likely.h" #include "mozilla/MacroArgs.h" #include "mozilla/MacroForEach.h" #define MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(X) \ static_assert(!std::is_destructible_v, \ "Reference-counted class " #X \ " should not have a public destructor. " \ "Make this class's destructor non-public"); inline nsISupports* ToSupports(decltype(nullptr)) { return nullptr; } inline nsISupports* ToSupports(nsISupports* aSupports) { return aSupports; } //////////////////////////////////////////////////////////////////////////////// // Macros to help detect thread-safety: #ifdef MOZ_THREAD_SAFETY_OWNERSHIP_CHECKS_SUPPORTED # include "prthread.h" /* needed for thread-safety checks */ class nsAutoOwningThread { public: nsAutoOwningThread(); // We move the actual assertion checks out-of-line to minimize code bloat, // but that means we have to pass a non-literal string to MOZ_CRASH_UNSAFE. // To make that more safe, the public interface requires a literal string // and passes that to the private interface; we can then be assured that we // effectively are passing a literal string to MOZ_CRASH_UNSAFE. template void AssertOwnership(const char (&aMsg)[N]) const { AssertCurrentThreadOwnsMe(aMsg); } bool IsCurrentThread() const; private: void AssertCurrentThreadOwnsMe(const char* aMsg) const; void* mThread; }; class nsISerialEventTarget; class nsAutoOwningEventTarget { public: nsAutoOwningEventTarget(); nsAutoOwningEventTarget(const nsAutoOwningEventTarget& aOther); // Per https://en.cppreference.com/w/cpp/language/move_constructor // there's no implicitly-declared move constructor if there are user-declared // copy constructors, and we have one, immediately above. nsAutoOwningEventTarget& operator=(const nsAutoOwningEventTarget& aRhs); // Per https://en.cppreference.com/w/cpp/language/move_assignment // there's no implicitly-declared move assignment operator if there are // user-declared copy assignment operators, and we have one, immediately // above. ~nsAutoOwningEventTarget(); // We move the actual assertion checks out-of-line to minimize code bloat, // but that means we have to pass a non-literal string to MOZ_CRASH_UNSAFE. // To make that more safe, the public interface requires a literal string // and passes that to the private interface; we can then be assured that we // effectively are passing a literal string to MOZ_CRASH_UNSAFE. template void AssertOwnership(const char (&aMsg)[N]) const { AssertCurrentThreadOwnsMe(aMsg); } bool IsCurrentThread() const; private: void AssertCurrentThreadOwnsMe(const char* aMsg) const; // A raw pointer to avoid nsCOMPtr.h dependency. nsISerialEventTarget* mTarget; }; # define NS_DECL_OWNINGTHREAD nsAutoOwningThread _mOwningThread; # define NS_DECL_OWNINGEVENTTARGET nsAutoOwningEventTarget _mOwningThread; # define NS_ASSERT_OWNINGTHREAD(_class) \ _mOwningThread.AssertOwnership(#_class " not thread-safe") #else // !MOZ_THREAD_SAFETY_OWNERSHIP_CHECKS_SUPPORTED # define NS_DECL_OWNINGTHREAD /* nothing */ # define NS_DECL_OWNINGEVENTTARGET /* nothing */ # define NS_ASSERT_OWNINGTHREAD(_class) ((void)0) #endif // MOZ_THREAD_SAFETY_OWNERSHIP_CHECKS_SUPPORTED // Macros for reference-count and constructor logging #if defined(NS_BUILD_REFCNT_LOGGING) # define NS_LOG_ADDREF(_p, _rc, _type, _size) \ NS_LogAddRef((_p), (_rc), (_type), (uint32_t)(_size)) # define NS_LOG_RELEASE(_p, _rc, _type) NS_LogRelease((_p), (_rc), (_type)) # define MOZ_ASSERT_CLASSNAME(_type) \ static_assert(std::is_class_v<_type>, \ "Token '" #_type "' is not a class type.") # define MOZ_ASSERT_NOT_ISUPPORTS(_type) \ static_assert(!std::is_base_of::value, \ "nsISupports classes don't need to call MOZ_COUNT_CTOR or " \ "MOZ_COUNT_DTOR"); // Note that the following constructor/destructor logging macros are redundant // for refcounted objects that log via the NS_LOG_ADDREF/NS_LOG_RELEASE macros. // Refcount logging is preferred. # define MOZ_COUNT_CTOR(_type) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ MOZ_ASSERT_NOT_ISUPPORTS(_type); \ NS_LogCtor((void*)this, #_type, sizeof(*this)); \ } while (0) # define MOZ_COUNT_CTOR_INHERITED(_type, _base) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ MOZ_ASSERT_CLASSNAME(_base); \ MOZ_ASSERT_NOT_ISUPPORTS(_type); \ NS_LogCtor((void*)this, #_type, sizeof(*this) - sizeof(_base)); \ } while (0) # define MOZ_LOG_CTOR(_ptr, _name, _size) \ do { \ NS_LogCtor((void*)_ptr, _name, _size); \ } while (0) # define MOZ_COUNT_DTOR(_type) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ MOZ_ASSERT_NOT_ISUPPORTS(_type); \ NS_LogDtor((void*)this, #_type, sizeof(*this)); \ } while (0) # define MOZ_COUNT_DTOR_INHERITED(_type, _base) \ do { \ MOZ_ASSERT_CLASSNAME(_type); \ MOZ_ASSERT_CLASSNAME(_base); \ MOZ_ASSERT_NOT_ISUPPORTS(_type); \ NS_LogDtor((void*)this, #_type, sizeof(*this) - sizeof(_base)); \ } while (0) # define MOZ_LOG_DTOR(_ptr, _name, _size) \ do { \ NS_LogDtor((void*)_ptr, _name, _size); \ } while (0) # define MOZ_COUNTED_DEFAULT_CTOR(_type) \ _type() { MOZ_COUNT_CTOR(_type); } # define MOZ_COUNTED_DTOR_META(_type, _prefix, _postfix) \ _prefix ~_type() _postfix { MOZ_COUNT_DTOR(_type); } # define MOZ_COUNTED_DTOR_NESTED(_type, _nestedName) \ ~_type() { MOZ_COUNT_DTOR(_nestedName); } /* nsCOMPtr.h allows these macros to be defined by clients * These logging functions require dynamic_cast, so they don't * do anything useful if we don't have dynamic_cast. * Note: The explicit comparison to nullptr is needed to avoid warnings * when _p is a nullptr itself. */ # define NSCAP_LOG_ASSIGNMENT(_c, _p) \ if (_p != nullptr) NS_LogCOMPtrAddRef((_c), ToSupports(_p)) # define NSCAP_LOG_RELEASE(_c, _p) \ if (_p) NS_LogCOMPtrRelease((_c), ToSupports(_p)) #else /* !NS_BUILD_REFCNT_LOGGING */ # define NS_LOG_ADDREF(_p, _rc, _type, _size) # define NS_LOG_RELEASE(_p, _rc, _type) # define MOZ_COUNT_CTOR(_type) # define MOZ_COUNT_CTOR_INHERITED(_type, _base) # define MOZ_LOG_CTOR(_ptr, _name, _size) # define MOZ_COUNT_DTOR(_type) # define MOZ_COUNT_DTOR_INHERITED(_type, _base) # define MOZ_LOG_DTOR(_ptr, _name, _size) # define MOZ_COUNTED_DEFAULT_CTOR(_type) _type() = default; # define MOZ_COUNTED_DTOR_META(_type, _prefix, _postfix) \ _prefix ~_type() _postfix = default; # define MOZ_COUNTED_DTOR_NESTED(_type, _nestedName) ~_type() = default; #endif /* NS_BUILD_REFCNT_LOGGING */ #define MOZ_COUNTED_DTOR(_type) MOZ_COUNTED_DTOR_META(_type, , ) #define MOZ_COUNTED_DTOR_OVERRIDE(_type) \ MOZ_COUNTED_DTOR_META(_type, , override) #define MOZ_COUNTED_DTOR_FINAL(_type) MOZ_COUNTED_DTOR_META(_type, , final) #define MOZ_COUNTED_DTOR_VIRTUAL(_type) MOZ_COUNTED_DTOR_META(_type, virtual, ) // Support for ISupports classes which interact with cycle collector. #ifdef HAVE_64BIT_BUILD # define NS_NUMBER_OF_FLAGS_IN_REFCNT 3 # define NS_IS_ON_MAINTHREAD (1 << 2) #else # define NS_NUMBER_OF_FLAGS_IN_REFCNT 2 #endif #define NS_IN_PURPLE_BUFFER (1 << 0) #define NS_IS_PURPLE (1 << 1) #define NS_REFCOUNT_CHANGE (1 << NS_NUMBER_OF_FLAGS_IN_REFCNT) #define NS_REFCOUNT_VALUE(_val) (_val >> NS_NUMBER_OF_FLAGS_IN_REFCNT) class nsCycleCollectingAutoRefCnt { public: typedef void (*Suspect)(void* aPtr, nsCycleCollectionParticipant* aCp, nsCycleCollectingAutoRefCnt* aRefCnt, bool* aShouldDelete); nsCycleCollectingAutoRefCnt() : mRefCntAndFlags(0) {} explicit nsCycleCollectingAutoRefCnt(uintptr_t aValue) : mRefCntAndFlags(aValue << NS_NUMBER_OF_FLAGS_IN_REFCNT) {} nsCycleCollectingAutoRefCnt(const nsCycleCollectingAutoRefCnt&) = delete; void operator=(const nsCycleCollectingAutoRefCnt&) = delete; MOZ_ALWAYS_INLINE uintptr_t incr(nsISupports* aOwner) { return incr(aOwner, nullptr); } MOZ_ALWAYS_INLINE uintptr_t incr(void* aOwner, nsCycleCollectionParticipant* aCp) { mRefCntAndFlags += NS_REFCOUNT_CHANGE; mRefCntAndFlags &= ~NS_IS_PURPLE; // For incremental cycle collection, use the purple buffer to track objects // that have been AddRef'd. if (!IsInPurpleBuffer()) { mRefCntAndFlags |= NS_IN_PURPLE_BUFFER; // Refcount isn't zero, so Suspect won't delete anything. MOZ_ASSERT(get() > 0); NS_CycleCollectorSuspect3(aOwner, aCp, this, nullptr); } return NS_REFCOUNT_VALUE(mRefCntAndFlags); } MOZ_ALWAYS_INLINE void stabilizeForDeletion() { // Set refcnt to 1 and mark us to be in the purple buffer. // This way decr won't call suspect again. mRefCntAndFlags = NS_REFCOUNT_CHANGE | NS_IN_PURPLE_BUFFER; } MOZ_ALWAYS_INLINE uintptr_t decr(nsISupports* aOwner, bool* aShouldDelete = nullptr) { return decr(aOwner, nullptr, aShouldDelete); } MOZ_ALWAYS_INLINE uintptr_t decr(void* aOwner, nsCycleCollectionParticipant* aCp, bool* aShouldDelete = nullptr) { MOZ_ASSERT(get() > 0); if (!IsInPurpleBuffer()) { mRefCntAndFlags -= NS_REFCOUNT_CHANGE; mRefCntAndFlags |= (NS_IN_PURPLE_BUFFER | NS_IS_PURPLE); uintptr_t retval = NS_REFCOUNT_VALUE(mRefCntAndFlags); // Suspect may delete 'aOwner' and 'this'! NS_CycleCollectorSuspect3(aOwner, aCp, this, aShouldDelete); return retval; } mRefCntAndFlags -= NS_REFCOUNT_CHANGE; mRefCntAndFlags |= (NS_IN_PURPLE_BUFFER | NS_IS_PURPLE); return NS_REFCOUNT_VALUE(mRefCntAndFlags); } MOZ_ALWAYS_INLINE void RemovePurple() { MOZ_ASSERT(IsPurple(), "must be purple"); mRefCntAndFlags &= ~NS_IS_PURPLE; } MOZ_ALWAYS_INLINE void RemoveFromPurpleBuffer() { MOZ_ASSERT(IsInPurpleBuffer()); mRefCntAndFlags &= ~(NS_IS_PURPLE | NS_IN_PURPLE_BUFFER); } MOZ_ALWAYS_INLINE bool IsPurple() const { return !!(mRefCntAndFlags & NS_IS_PURPLE); } MOZ_ALWAYS_INLINE bool IsInPurpleBuffer() const { return !!(mRefCntAndFlags & NS_IN_PURPLE_BUFFER); } // Cycle collected objects can only be used on a single thread, so if we ever // see an object on the main thread, it will always be on the main thread. // The cycle collector then uses this information to utilize faster nursery // purple buffer on the main thread. // The method works only on 64 bit systems. MOZ_ALWAYS_INLINE void SetIsOnMainThread() { #ifdef HAVE_64BIT_BUILD mRefCntAndFlags |= NS_IS_ON_MAINTHREAD; #endif } #ifdef HAVE_64BIT_BUILD // The NS_IS_ON_MAINTHREAD flag only exists on 64-bit builds. MOZ_ALWAYS_INLINE bool IsOnMainThread() { return !!(mRefCntAndFlags & NS_IS_ON_MAINTHREAD); } #endif MOZ_ALWAYS_INLINE nsrefcnt get() const { return NS_REFCOUNT_VALUE(mRefCntAndFlags); } MOZ_ALWAYS_INLINE operator nsrefcnt() const { return get(); } private: uintptr_t mRefCntAndFlags; }; class nsAutoRefCnt { public: nsAutoRefCnt() : mValue(0) {} explicit nsAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {} nsAutoRefCnt(const nsAutoRefCnt&) = delete; void operator=(const nsAutoRefCnt&) = delete; // only support prefix increment/decrement nsrefcnt operator++() { return ++mValue; } nsrefcnt operator--() { return --mValue; } nsrefcnt operator=(nsrefcnt aValue) { return (mValue = aValue); } operator nsrefcnt() const { return mValue; } nsrefcnt get() const { return mValue; } static const bool isThreadSafe = false; private: nsrefcnt operator++(int) = delete; nsrefcnt operator--(int) = delete; nsrefcnt mValue; }; namespace mozilla { class ThreadSafeAutoRefCnt { public: ThreadSafeAutoRefCnt() : mValue(0) {} explicit ThreadSafeAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {} ThreadSafeAutoRefCnt(const ThreadSafeAutoRefCnt&) = delete; void operator=(const ThreadSafeAutoRefCnt&) = delete; // only support prefix increment/decrement MOZ_ALWAYS_INLINE nsrefcnt operator++() { // Memory synchronization is not required when incrementing a // reference count. The first increment of a reference count on a // thread is not important, since the first use of the object on a // thread can happen before it. What is important is the transfer // of the pointer to that thread, which may happen prior to the // first increment on that thread. The necessary memory // synchronization is done by the mechanism that transfers the // pointer between threads. return mValue.fetch_add(1, std::memory_order_relaxed) + 1; } MOZ_ALWAYS_INLINE nsrefcnt operator--() { // Since this may be the last release on this thread, we need // release semantics so that prior writes on this thread are visible // to the thread that destroys the object when it reads mValue with // acquire semantics. nsrefcnt result = mValue.fetch_sub(1, std::memory_order_release) - 1; if (result == 0) { // We're going to destroy the object on this thread, so we need // acquire semantics to synchronize with the memory released by // the last release on other threads, that is, to ensure that // writes prior to that release are now visible on this thread. #ifdef MOZ_TSAN // TSan doesn't understand std::atomic_thread_fence, so in order // to avoid a false positive for every time a refcounted object // is deleted, we replace the fence with an atomic operation. mValue.load(std::memory_order_acquire); #else std::atomic_thread_fence(std::memory_order_acquire); #endif } return result; } MOZ_ALWAYS_INLINE nsrefcnt operator=(nsrefcnt aValue) { // Use release semantics since we're not sure what the caller is // doing. mValue.store(aValue, std::memory_order_release); return aValue; } MOZ_ALWAYS_INLINE operator nsrefcnt() const { return get(); } MOZ_ALWAYS_INLINE nsrefcnt get() const { // Use acquire semantics since we're not sure what the caller is // doing. return mValue.load(std::memory_order_acquire); } static const bool isThreadSafe = true; private: nsrefcnt operator++(int) = delete; nsrefcnt operator--(int) = delete; std::atomic mValue; }; namespace detail { // Type trait indicating whether a given XPCOM interface class may only be // implemented by types with threadsafe refcounts. This is specialized for // classes with the `rust_sync` annotation within XPIDL-generated header files, // and checked within macro-generated QueryInterface implementations. template class InterfaceNeedsThreadSafeRefCnt : public std::false_type {}; } } // namespace mozilla /////////////////////////////////////////////////////////////////////////////// /** * Declare the reference count variable and the implementations of the * AddRef and QueryInterface methods. */ #define NS_DECL_ISUPPORTS \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ using HasThreadSafeRefCnt = std::false_type; \ \ protected: \ nsAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: #define NS_DECL_ISUPPORTS_ONEVENTTARGET \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ using HasThreadSafeRefCnt = std::false_type; \ \ protected: \ nsAutoRefCnt mRefCnt; \ NS_DECL_OWNINGEVENTTARGET \ public: #define NS_DECL_THREADSAFE_ISUPPORTS \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ using HasThreadSafeRefCnt = std::true_type; \ \ protected: \ ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: #define NS_DECL_CYCLE_COLLECTING_ISUPPORTS \ NS_DECL_CYCLE_COLLECTING_ISUPPORTS_META(override) \ NS_IMETHOD_(void) DeleteCycleCollectable(void); \ \ public: #define NS_DECL_CYCLE_COLLECTING_ISUPPORTS_FINAL \ NS_DECL_CYCLE_COLLECTING_ISUPPORTS_META(final) \ NS_IMETHOD_(void) DeleteCycleCollectable(void); \ \ public: #define NS_DECL_CYCLE_COLLECTING_ISUPPORTS_META(...) \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) __VA_ARGS__; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) __VA_ARGS__; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) __VA_ARGS__; \ using HasThreadSafeRefCnt = std::false_type; \ \ protected: \ nsCycleCollectingAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: /////////////////////////////////////////////////////////////////////////////// /* * Implementation of AddRef and Release for non-nsISupports (ie "native") * cycle-collected classes that use the purple buffer to avoid leaks. */ #define NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = \ mRefCnt.incr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return count; #define NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = \ mRefCnt.decr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ NS_LOG_RELEASE(this, count, #_class); \ return count; #define NS_IMPL_CYCLE_COLLECTING_NATIVE_ADDREF(_class) \ NS_METHOD_(MozExternalRefCountType) _class::AddRef(void) { \ NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \ } #define NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE_WITH_LAST_RELEASE(_class, \ _last) \ NS_METHOD_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ bool shouldDelete = false; \ nsrefcnt count = \ mRefCnt.decr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant(), \ &shouldDelete); \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ mRefCnt.incr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ _last; \ mRefCnt.decr(static_cast(this), \ _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ if (shouldDelete) { \ mRefCnt.stabilizeForDeletion(); \ DeleteCycleCollectable(); \ } \ } \ return count; \ } #define NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE(_class) \ NS_METHOD_(MozExternalRefCountType) _class::Release(void) { \ NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ } #define NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(_class) \ NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING_META(_class, NS_METHOD_) #define NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING_VIRTUAL(_class) \ NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING_META(_class, NS_IMETHOD_) #define NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING_INHERITED(_class) \ NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING_META(_class, NS_METHOD_, \ override) #define NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING_META(_class, _decl, \ ...) \ public: \ _decl(MozExternalRefCountType) AddRef(void) __VA_ARGS__{ \ NS_IMPL_CC_NATIVE_ADDREF_BODY(_class)} _decl(MozExternalRefCountType) \ Release(void) __VA_ARGS__ { \ NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ } \ using HasThreadSafeRefCnt = std::false_type; \ \ protected: \ nsCycleCollectingAutoRefCnt mRefCnt; \ NS_DECL_OWNINGTHREAD \ public: /////////////////////////////////////////////////////////////////////////////// /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class. * * @param _class The name of the class implementing the method * @param _destroy A statement that is executed when the object's * refcount drops to zero. * @param _decl Name of the macro to be used for the return type of the * AddRef & Release methods (typically NS_IMETHOD_ or NS_METHOD_). * @param optional override Mark the AddRef & Release methods as overrides. */ #define NS_INLINE_DECL_REFCOUNTING_META(_class, _decl, _destroy, _owning, ...) \ public: \ _decl(MozExternalRefCountType) AddRef(void) __VA_ARGS__ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD(_class); \ ++mRefCnt; \ NS_LOG_ADDREF(this, mRefCnt, #_class, sizeof(*this)); \ return mRefCnt; \ } \ _decl(MozExternalRefCountType) Release(void) __VA_ARGS__ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ --mRefCnt; \ NS_LOG_RELEASE(this, mRefCnt, #_class); \ if (mRefCnt == 0) { \ mRefCnt = 1; /* stabilize */ \ _destroy; \ return 0; \ } \ return mRefCnt; \ } \ using HasThreadSafeRefCnt = std::false_type; \ \ protected: \ nsAutoRefCnt mRefCnt; \ _owning public: /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class. * * @param _class The name of the class implementing the method * @param _destroy A statement that is executed when the object's * refcount drops to zero. * @param optional override Mark the AddRef & Release methods as overrides. */ #define NS_INLINE_DECL_REFCOUNTING_WITH_DESTROY(_class, _destroy, ...) \ NS_INLINE_DECL_REFCOUNTING_META(_class, NS_METHOD_, _destroy, \ NS_DECL_OWNINGTHREAD, __VA_ARGS__) /** * Like NS_INLINE_DECL_REFCOUNTING_WITH_DESTROY with AddRef & Release declared * virtual. */ #define NS_INLINE_DECL_VIRTUAL_REFCOUNTING_WITH_DESTROY(_class, _destroy, ...) \ NS_INLINE_DECL_REFCOUNTING_META(_class, NS_IMETHOD_, _destroy, \ NS_DECL_OWNINGTHREAD, __VA_ARGS__) /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class. * * @param _class The name of the class implementing the method * @param optional override Mark the AddRef & Release methods as overrides. */ #define NS_INLINE_DECL_REFCOUNTING(_class, ...) \ NS_INLINE_DECL_REFCOUNTING_WITH_DESTROY(_class, delete (this), __VA_ARGS__) /** * Like NS_INLINE_DECL_REFCOUNTING, however the thread safety check will work * with any nsISerialEventTarget. This is a workaround until bug 1648031 is * properly resolved. Once this is done, it will be possible to use * NS_INLINE_DECL_REFCOUNTING under all circumstances. */ #define NS_INLINE_DECL_REFCOUNTING_ONEVENTTARGET(_class, ...) \ NS_INLINE_DECL_REFCOUNTING_META(_class, NS_METHOD_, delete (this), \ NS_DECL_OWNINGEVENTTARGET, __VA_ARGS__) #define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, _decl, _destroy, \ ...) \ public: \ _decl(MozExternalRefCountType) AddRef(void) __VA_ARGS__ { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ nsrefcnt count = ++mRefCnt; \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return (nsrefcnt)count; \ } \ _decl(MozExternalRefCountType) Release(void) __VA_ARGS__ { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ nsrefcnt count = --mRefCnt; \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ _destroy; \ return 0; \ } \ return count; \ } \ using HasThreadSafeRefCnt = std::true_type; \ \ protected: \ ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \ \ public: /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class in a threadsafe manner. * * DOES NOT DO REFCOUNT STABILIZATION! * * @param _class The name of the class implementing the method * @param _destroy A statement that is executed when the object's * refcount drops to zero. * @param optional override Mark the AddRef & Release methods as overrides. */ #define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DESTROY(_class, _destroy, \ ...) \ NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, NS_METHOD_, _destroy, \ __VA_ARGS__) /** * Like NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DESTROY with AddRef & Release * declared virtual. */ #define NS_INLINE_DECL_THREADSAFE_VIRTUAL_REFCOUNTING_WITH_DESTROY( \ _class, _destroy, ...) \ NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, NS_IMETHOD_, _destroy, \ __VA_ARGS__) /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class in a threadsafe manner. * * DOES NOT DO REFCOUNT STABILIZATION! * * @param _class The name of the class implementing the method * @param optional override Mark the AddRef & Release methods as overrides. */ #define NS_INLINE_DECL_THREADSAFE_REFCOUNTING(_class, ...) \ NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DESTROY(_class, delete (this), \ __VA_ARGS__) /** * Like NS_INLINE_DECL_THREADSAFE_REFCOUNTING with AddRef & Release declared * virtual. */ #define NS_INLINE_DECL_THREADSAFE_VIRTUAL_REFCOUNTING(_class, ...) \ NS_INLINE_DECL_THREADSAFE_VIRTUAL_REFCOUNTING_WITH_DESTROY( \ _class, delete (this), __VA_ARGS__) #if !defined(XPCOM_GLUE_AVOID_NSPR) class nsISerialEventTarget; namespace mozilla { // Forward-declare `GetMainThreadSerialEventTarget`, as `nsISupportsImpl.h` // cannot include `nsThreadUtils.h`. nsISerialEventTarget* GetMainThreadSerialEventTarget(); namespace detail { using DeleteVoidFunction = void(void*); void ProxyDeleteVoid(const char* aRunnableName, nsISerialEventTarget* aEventTarget, void* aSelf, DeleteVoidFunction* aDeleteFunc); } // namespace detail } // namespace mozilla /** * Helper for _WITH_DELETE_ON_EVENT_TARGET threadsafe refcounting macros which * provides an implementation of `_destroy` */ # define NS_PROXY_DELETE_TO_EVENT_TARGET(_class, _target) \ ::mozilla::detail::ProxyDeleteVoid( \ "ProxyDelete " #_class, _target, this, \ [](void* self) { delete static_cast<_class*>(self); }) /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class in a threadsafe manner, ensuring the * destructor runs on a specific nsISerialEventTarget. * * DOES NOT DO REFCOUNT STABILIZATION! * * @param _class The name of the class implementing the method * @param _target nsISerialEventTarget to run the class's destructor on * @param optional override Mark the AddRef & Release methods as overrides */ # define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DELETE_ON_EVENT_TARGET( \ _class, _target, ...) \ NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DESTROY( \ _class, NS_PROXY_DELETE_TO_EVENT_TARGET(_class, _target), __VA_ARGS__) /** * Use this macro to declare and implement the AddRef & Release methods for a * given non-XPCOM _class in a threadsafe manner, ensuring the * destructor runs on the main thread. * * DOES NOT DO REFCOUNT STABILIZATION! * * @param _class The name of the class implementing the method * @param optional override Mark the AddRef & Release methods as overrides */ # define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DELETE_ON_MAIN_THREAD( \ _class, ...) \ NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DELETE_ON_EVENT_TARGET( \ _class, ::mozilla::GetMainThreadSerialEventTarget(), __VA_ARGS__) #endif /** * Use this macro in interface classes that you want to be able to reference * using RefPtr, but don't want to provide a refcounting implemenation. The * refcounting implementation can be provided by concrete subclasses that * implement the interface. */ #define NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING \ public: \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) = 0; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) = 0; \ \ public: /** * Use this macro to implement the AddRef method for a given _class * @param _class The name of the class implementing the method * @param _name The class name to be passed to XPCOM leak checking */ #define NS_IMPL_NAMED_ADDREF(_class, _name) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ MOZ_ASSERT(_name != nullptr, "Must specify a name"); \ if (!mRefCnt.isThreadSafe) NS_ASSERT_OWNINGTHREAD(_class); \ nsrefcnt count = ++mRefCnt; \ NS_LOG_ADDREF(this, count, _name, sizeof(*this)); \ return count; \ } /** * Use this macro to implement the AddRef method for a given _class * @param _class The name of the class implementing the method */ #define NS_IMPL_ADDREF(_class) NS_IMPL_NAMED_ADDREF(_class, #_class) /** * Use this macro to implement the AddRef method for a given _class * implemented as a wholly owned aggregated object intended to implement * interface(s) for its owner * @param _class The name of the class implementing the method * @param _aggregator the owning/containing object */ #define NS_IMPL_ADDREF_USING_AGGREGATOR(_class, _aggregator) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(_aggregator, "null aggregator"); \ return (_aggregator)->AddRef(); \ } // We decrement the refcnt before logging the actual release, but when logging // named things, accessing the name may not be valid after the refcnt // decrement, because the object may have been destroyed on a different thread. // Use this macro to ensure that we have a local copy of the name prior to // the refcnt decrement. (We use a macro to make absolutely sure the name // isn't loaded in builds where it wouldn't be used.) #ifdef NS_BUILD_REFCNT_LOGGING # define NS_LOAD_NAME_BEFORE_RELEASE(localname, _name) \ const char* const localname = _name #else # define NS_LOAD_NAME_BEFORE_RELEASE(localname, _name) #endif /** * Use this macro to implement the Release method for a given * _class. * @param _class The name of the class implementing the method * @param _name The class name to be passed to XPCOM leak checking * @param _destroy A statement that is executed when the object's * refcount drops to zero. * * For example, * * NS_IMPL_RELEASE_WITH_DESTROY(Foo, "Foo", Destroy(this)) * * will cause * * Destroy(this); * * to be invoked when the object's refcount drops to zero. This * allows for arbitrary teardown activity to occur (e.g., deallocation * of object allocated with placement new). */ #define NS_IMPL_NAMED_RELEASE_WITH_DESTROY(_class, _name, _destroy) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ MOZ_ASSERT(_name != nullptr, "Must specify a name"); \ if (!mRefCnt.isThreadSafe) NS_ASSERT_OWNINGTHREAD(_class); \ NS_LOAD_NAME_BEFORE_RELEASE(nametmp, _name); \ nsrefcnt count = --mRefCnt; \ NS_LOG_RELEASE(this, count, nametmp); \ if (count == 0) { \ mRefCnt = 1; /* stabilize */ \ _destroy; \ return 0; \ } \ return count; \ } #define NS_IMPL_RELEASE_WITH_DESTROY(_class, _destroy) \ NS_IMPL_NAMED_RELEASE_WITH_DESTROY(_class, #_class, _destroy) /** * Use this macro to implement the Release method for a given _class * @param _class The name of the class implementing the method * * A note on the 'stabilization' of the refcnt to one. At that point, * the object's refcount will have gone to zero. The object's * destructor may trigger code that attempts to QueryInterface() and * Release() 'this' again. Doing so will temporarily increment and * decrement the refcount. (Only a logic error would make one try to * keep a permanent hold on 'this'.) To prevent re-entering the * destructor, we make sure that no balanced refcounting can return * the refcount to |0|. */ #define NS_IMPL_RELEASE(_class) \ NS_IMPL_RELEASE_WITH_DESTROY(_class, delete (this)) #define NS_IMPL_NAMED_RELEASE(_class, _name) \ NS_IMPL_NAMED_RELEASE_WITH_DESTROY(_class, _name, delete (this)) /** * Use this macro to implement the Release method for a given _class * implemented as a wholly owned aggregated object intended to implement * interface(s) for its owner * @param _class The name of the class implementing the method * @param _aggregator the owning/containing object */ #define NS_IMPL_RELEASE_USING_AGGREGATOR(_class, _aggregator) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(_aggregator, "null aggregator"); \ return (_aggregator)->Release(); \ } #define NS_IMPL_CYCLE_COLLECTING_ADDREF(_class) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsISupports* base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.incr(base); \ NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ return count; \ } #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(_class, _destroy) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ nsISupports* base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.decr(base); \ NS_LOG_RELEASE(this, count, #_class); \ return count; \ } \ NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { _destroy; } #define NS_IMPL_CYCLE_COLLECTING_RELEASE(_class) \ NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_DESTROY(_class, delete (this)) // _LAST_RELEASE can be useful when certain resources should be released // as soon as we know the object will be deleted. #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE(_class, _last) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ bool shouldDelete = false; \ nsISupports* base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.decr(base, &shouldDelete); \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ mRefCnt.incr(base); \ _last; \ mRefCnt.decr(base); \ if (shouldDelete) { \ mRefCnt.stabilizeForDeletion(); \ DeleteCycleCollectable(); \ } \ } \ return count; \ } \ NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { delete this; } // This macro is same as NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE // except it doesn't have DeleteCycleCollectable. #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_LAST_RELEASE_AND_DESTROY( \ _class, _last, _destroy) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ bool shouldDelete = false; \ nsISupports* base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.decr(base, &shouldDelete); \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ mRefCnt.incr(base); \ _last; \ mRefCnt.decr(base); \ if (shouldDelete) { \ mRefCnt.stabilizeForDeletion(); \ DeleteCycleCollectable(); \ } \ } \ return count; \ } \ NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { _destroy; } // _WITH_INTERRUPTABLE_LAST_RELEASE can be useful when certain resources // should be released as soon as we know the object will be deleted and the // instance may be cached for reuse. // _last is performed for cleaning up its resources. Then, _maybeInterrupt is // tested and when it returns true, this stops deleting the instance. // (Note that it's not allowed to grab the instance with nsCOMPtr or RefPtr // during _last is performed.) // Therefore, when _maybeInterrupt returns true, the instance has to be grabbed // by nsCOMPtr or RefPtr. #define NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_INTERRUPTABLE_LAST_RELEASE( \ _class, _last, _maybeInterrupt) \ NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) { \ MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ bool shouldDelete = false; \ nsISupports* base = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ nsrefcnt count = mRefCnt.decr(base, &shouldDelete); \ NS_LOG_RELEASE(this, count, #_class); \ if (count == 0) { \ mRefCnt.incr(base); \ _last; \ mRefCnt.decr(base); \ if (_maybeInterrupt) { \ MOZ_ASSERT(mRefCnt.get() > 0); \ return mRefCnt.get(); \ } \ if (shouldDelete) { \ mRefCnt.stabilizeForDeletion(); \ DeleteCycleCollectable(); \ } \ } \ return count; \ } \ NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { delete this; } /////////////////////////////////////////////////////////////////////////////// namespace mozilla::detail { // Helper which is roughly equivalent to NS_GET_IID, which also performs static // assertions that `Class` is allowed to implement the given XPCOM interface. // // These assertions are done like this to allow them to be used within the // `NS_INTERFACE_TABLE_ENTRY` macro, though they are also used in // `NS_IMPL_QUERY_BODY`. template constexpr const nsIID& GetImplementedIID() { if constexpr (mozilla::detail::InterfaceNeedsThreadSafeRefCnt< Interface>::value) { static_assert(Class::HasThreadSafeRefCnt::value, "Cannot implement a threadsafe interface with " "non-threadsafe refcounting!"); } return NS_GET_TEMPLATE_IID(Interface); } template constexpr const nsIID& kImplementedIID = GetImplementedIID(); } /** * There are two ways of implementing QueryInterface, and we use both: * * Table-driven QueryInterface uses a static table of IID->offset mappings * and a shared helper function. Using it tends to reduce codesize and improve * runtime performance (due to processor cache hits). * * Macro-driven QueryInterface generates a QueryInterface function directly * using common macros. This is necessary if special QueryInterface features * are being used (such as tearoffs and conditional interfaces). * * These methods can be combined into a table-driven function call followed * by custom code for tearoffs and conditionals. */ struct QITableEntry { const nsIID* iid; // null indicates end of the QITableEntry array int32_t offset; }; nsresult NS_FASTCALL NS_TableDrivenQI(void* aThis, REFNSIID aIID, void** aInstancePtr, const QITableEntry* aEntries); /** * Implement table-driven queryinterface */ #define NS_INTERFACE_TABLE_HEAD(_class) \ NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) { \ NS_ASSERTION(aInstancePtr, \ "QueryInterface requires a non-NULL destination!"); \ nsresult rv = NS_ERROR_FAILURE; #define NS_INTERFACE_TABLE_BEGIN static const QITableEntry table[] = { #define NS_INTERFACE_TABLE_ENTRY(_class, _interface) \ {&mozilla::detail::kImplementedIID<_class, _interface>, \ int32_t( \ reinterpret_cast(static_cast<_interface*>((_class*)0x1000)) - \ reinterpret_cast((_class*)0x1000))}, #define NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(_class, _interface, _implClass) \ {&mozilla::detail::kImplementedIID<_class, _interface>, \ int32_t(reinterpret_cast(static_cast<_interface*>( \ static_cast<_implClass*>((_class*)0x1000))) - \ reinterpret_cast((_class*)0x1000))}, /* * XXX: we want to use mozilla::ArrayLength (or equivalent, * MOZ_ARRAY_LENGTH) in this condition, but some versions of GCC don't * see that the static_assert condition is actually constant in those * cases, even with constexpr support (?). */ #define NS_INTERFACE_TABLE_END_WITH_PTR(_ptr) \ { nullptr, 0 } \ } \ ; \ static_assert((sizeof(table) / sizeof(table[0])) > 1, \ "need at least 1 interface"); \ rv = NS_TableDrivenQI(static_cast(_ptr), aIID, aInstancePtr, table); #define NS_INTERFACE_TABLE_END \ NS_INTERFACE_TABLE_END_WITH_PTR \ (this) #define NS_INTERFACE_TABLE_TAIL \ return rv; \ } #define NS_INTERFACE_TABLE_TAIL_INHERITING(_baseclass) \ if (NS_SUCCEEDED(rv)) return rv; \ return _baseclass::QueryInterface(aIID, aInstancePtr); \ } #define NS_INTERFACE_TABLE_TAIL_USING_AGGREGATOR(_aggregator) \ if (NS_SUCCEEDED(rv)) return rv; \ NS_ASSERTION(_aggregator, "null aggregator"); \ return _aggregator->QueryInterface(aIID, aInstancePtr) \ } /** * This implements query interface with two assumptions: First, the * class in question implements nsISupports and its own interface and * nothing else. Second, the implementation of the class's primary * inheritance chain leads to its own interface. * * @param _class The name of the class implementing the method * @param _classiiddef The name of the #define symbol that defines the IID * for the class (e.g. NS_ISUPPORTS_IID) */ #define NS_IMPL_QUERY_HEAD(_class) \ NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) { \ NS_ASSERTION(aInstancePtr, \ "QueryInterface requires a non-NULL destination!"); \ nsISupports* foundInterface; #define NS_IMPL_QUERY_BODY_IID(_interface) \ mozilla::detail::kImplementedIID, \ _interface> #define NS_IMPL_QUERY_BODY(_interface) \ if (aIID.Equals(NS_IMPL_QUERY_BODY_IID(_interface))) \ foundInterface = static_cast<_interface*>(this); \ else #define NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition) \ if ((condition) && aIID.Equals(NS_IMPL_QUERY_BODY_IID(_interface))) \ foundInterface = static_cast<_interface*>(this); \ else #define NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass) \ if (aIID.Equals(NS_IMPL_QUERY_BODY_IID(_interface))) \ foundInterface = static_cast<_interface*>(static_cast<_implClass*>(this)); \ else // Use this for querying to concrete class types which cannot be unambiguously // cast to nsISupports. See also nsQueryObject.h. #define NS_IMPL_QUERY_BODY_CONCRETE(_class) \ if (aIID.Equals(NS_IMPL_QUERY_BODY_IID(_class))) { \ *aInstancePtr = do_AddRef(static_cast<_class*>(this)).take(); \ return NS_OK; \ } else #define NS_IMPL_QUERY_BODY_AGGREGATED(_interface, _aggregate) \ if (aIID.Equals(NS_IMPL_QUERY_BODY_IID(_interface))) \ foundInterface = static_cast<_interface*>(_aggregate); \ else #define NS_IMPL_QUERY_TAIL_GUTS \ foundInterface = 0; \ nsresult status; \ if (!foundInterface) { \ /* nsISupports should be handled by this point. If not, fail. */ \ MOZ_ASSERT(!aIID.Equals(NS_GET_IID(nsISupports))); \ status = NS_NOINTERFACE; \ } else { \ NS_ADDREF(foundInterface); \ status = NS_OK; \ } \ *aInstancePtr = foundInterface; \ return status; \ } #define NS_IMPL_QUERY_TAIL_INHERITING(_baseclass) \ foundInterface = 0; \ nsresult status; \ if (!foundInterface) \ status = _baseclass::QueryInterface(aIID, (void**)&foundInterface); \ else { \ NS_ADDREF(foundInterface); \ status = NS_OK; \ } \ *aInstancePtr = foundInterface; \ return status; \ } #define NS_IMPL_QUERY_TAIL_USING_AGGREGATOR(_aggregator) \ foundInterface = 0; \ nsresult status; \ if (!foundInterface) { \ NS_ASSERTION(_aggregator, "null aggregator"); \ status = _aggregator->QueryInterface(aIID, (void**)&foundInterface); \ } else { \ NS_ADDREF(foundInterface); \ status = NS_OK; \ } \ *aInstancePtr = foundInterface; \ return status; \ } #define NS_IMPL_QUERY_TAIL(_supports_interface) \ NS_IMPL_QUERY_BODY_AMBIGUOUS(nsISupports, _supports_interface) \ NS_IMPL_QUERY_TAIL_GUTS /* This is the new scheme. Using this notation now will allow us to switch to a table driven mechanism when it's ready. Note the difference between this and the (currently) underlying NS_IMPL_QUERY_INTERFACE mechanism. You must explicitly mention |nsISupports| when using the interface maps. */ #define NS_INTERFACE_MAP_BEGIN(_implClass) NS_IMPL_QUERY_HEAD(_implClass) #define NS_INTERFACE_MAP_ENTRY(_interface) NS_IMPL_QUERY_BODY(_interface) #define NS_INTERFACE_MAP_ENTRY_CONDITIONAL(_interface, condition) \ NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition) #define NS_INTERFACE_MAP_ENTRY_AGGREGATED(_interface, _aggregate) \ NS_IMPL_QUERY_BODY_AGGREGATED(_interface, _aggregate) #define NS_INTERFACE_MAP_END NS_IMPL_QUERY_TAIL_GUTS #define NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(_interface, _implClass) \ NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass) #define NS_INTERFACE_MAP_ENTRY_CONCRETE(_class) \ NS_IMPL_QUERY_BODY_CONCRETE(_class) #define NS_INTERFACE_MAP_END_INHERITING(_baseClass) \ NS_IMPL_QUERY_TAIL_INHERITING(_baseClass) #define NS_INTERFACE_MAP_END_AGGREGATED(_aggregator) \ NS_IMPL_QUERY_TAIL_USING_AGGREGATOR(_aggregator) #define NS_INTERFACE_TABLE0(_class) \ NS_INTERFACE_TABLE_BEGIN \ NS_INTERFACE_TABLE_ENTRY(_class, nsISupports) \ NS_INTERFACE_TABLE_END #define NS_INTERFACE_TABLE(aClass, ...) \ static_assert(MOZ_ARG_COUNT(__VA_ARGS__) > 0, \ "Need more arguments to NS_INTERFACE_TABLE"); \ NS_INTERFACE_TABLE_BEGIN \ MOZ_FOR_EACH(NS_INTERFACE_TABLE_ENTRY, (aClass, ), (__VA_ARGS__)) \ NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(aClass, nsISupports, \ MOZ_ARG_1(__VA_ARGS__)) \ NS_INTERFACE_TABLE_END #define NS_IMPL_QUERY_INTERFACE0(_class) \ NS_INTERFACE_TABLE_HEAD(_class) \ NS_INTERFACE_TABLE0(_class) \ NS_INTERFACE_TABLE_TAIL #define NS_IMPL_QUERY_INTERFACE(aClass, ...) \ NS_INTERFACE_TABLE_HEAD(aClass) \ NS_INTERFACE_TABLE(aClass, __VA_ARGS__) \ NS_INTERFACE_TABLE_TAIL /** * Declare that you're going to inherit from something that already * implements nsISupports, but also implements an additional interface, thus * causing an ambiguity. In this case you don't need another mRefCnt, you * just need to forward the definitions to the appropriate superclass. E.g. * * class Bar : public Foo, public nsIBar { // both provide nsISupports * public: * NS_DECL_ISUPPORTS_INHERITED * ...other nsIBar and Bar methods... * }; */ #define NS_DECL_ISUPPORTS_INHERITED \ public: \ NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override; \ NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ NS_IMETHOD_(MozExternalRefCountType) Release(void) override; /** * These macros can be used in conjunction with NS_DECL_ISUPPORTS_INHERITED * to implement the nsISupports methods, forwarding the invocations to a * superclass that already implements nsISupports. Don't do anything for * subclasses of Runnable because it deals with subclass logging in its own * way, using the mName field. * * Note that I didn't make these inlined because they're virtual methods. */ namespace mozilla { class Runnable; namespace detail { class SupportsThreadSafeWeakPtrBase; // Don't NS_LOG_{ADDREF,RELEASE} when inheriting from `Runnable*` or types with // thread safe weak references, as it will generate incorrect refcnt logs due to // the thread-safe `Upgrade()` call's refcount modifications not calling through // the derived class' `AddRef()` and `Release()` methods. template constexpr bool ShouldLogInheritedRefcnt = !std::is_convertible_v && !std::is_base_of_v; } } // namespace mozilla #define NS_IMPL_ADDREF_INHERITED_GUTS(Class, Super) \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class) \ nsrefcnt r = Super::AddRef(); \ if constexpr (::mozilla::detail::ShouldLogInheritedRefcnt) { \ NS_LOG_ADDREF(this, r, #Class, sizeof(*this)); \ } \ return r /* Purposefully no trailing semicolon */ #define NS_IMPL_ADDREF_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) { \ NS_IMPL_ADDREF_INHERITED_GUTS(Class, Super); \ } #define NS_IMPL_RELEASE_INHERITED_GUTS(Class, Super) \ nsrefcnt r = Super::Release(); \ if constexpr (::mozilla::detail::ShouldLogInheritedRefcnt) { \ NS_LOG_RELEASE(this, r, #Class); \ } \ return r /* Purposefully no trailing semicolon */ #define NS_IMPL_RELEASE_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) { \ NS_IMPL_RELEASE_INHERITED_GUTS(Class, Super); \ } /** * As above but not logging the addref/release; needed if the base * class might be aggregated. */ #define NS_IMPL_NONLOGGING_ADDREF_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) { \ MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class) \ return Super::AddRef(); \ } #define NS_IMPL_NONLOGGING_RELEASE_INHERITED(Class, Super) \ NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) { \ return Super::Release(); \ } #define NS_INTERFACE_TABLE_INHERITED0(Class) /* Nothing to do here */ #define NS_INTERFACE_TABLE_INHERITED(aClass, ...) \ static_assert(MOZ_ARG_COUNT(__VA_ARGS__) > 0, \ "Need more arguments to NS_INTERFACE_TABLE_INHERITED"); \ NS_INTERFACE_TABLE_BEGIN \ MOZ_FOR_EACH(NS_INTERFACE_TABLE_ENTRY, (aClass, ), (__VA_ARGS__)) \ NS_INTERFACE_TABLE_END #define NS_IMPL_QUERY_INTERFACE_INHERITED(aClass, aSuper, ...) \ NS_INTERFACE_TABLE_HEAD(aClass) \ NS_INTERFACE_TABLE_INHERITED(aClass, __VA_ARGS__) \ NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper) /** * Convenience macros for implementing all nsISupports methods for * a simple class. * @param _class The name of the class implementing the method * @param _classiiddef The name of the #define symbol that defines the IID * for the class (e.g. NS_ISUPPORTS_IID) */ #define NS_IMPL_ISUPPORTS0(_class) \ NS_IMPL_ADDREF(_class) \ NS_IMPL_RELEASE(_class) \ NS_IMPL_QUERY_INTERFACE0(_class) #define NS_IMPL_ISUPPORTS(aClass, ...) \ NS_IMPL_ADDREF(aClass) \ NS_IMPL_RELEASE(aClass) \ NS_IMPL_QUERY_INTERFACE(aClass, __VA_ARGS__) // When possible, prefer NS_INLINE_DECL_REFCOUNTING_INHERITED to // NS_IMPL_ISUPPORTS_INHERITED0. #define NS_IMPL_ISUPPORTS_INHERITED0(aClass, aSuper) \ NS_INTERFACE_TABLE_HEAD(aClass) \ NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper) \ NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \ NS_IMPL_RELEASE_INHERITED(aClass, aSuper) #define NS_IMPL_ISUPPORTS_INHERITED(aClass, aSuper, ...) \ NS_IMPL_QUERY_INTERFACE_INHERITED(aClass, aSuper, __VA_ARGS__) \ NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \ NS_IMPL_RELEASE_INHERITED(aClass, aSuper) /** * A macro to declare and implement inherited addref/release for a class which * doesn't have or need to override QueryInterface from its base class. * * Note: This macro always overrides the `AddRef` and `Release` methods, * including when refcount logging is disabled, meaning that it will implement * the `AddRef` or `Release` method from another virtual base class. */ #define NS_INLINE_DECL_REFCOUNTING_INHERITED(Class, Super) \ NS_IMETHOD_(MozExternalRefCountType) AddRef() override { \ NS_IMPL_ADDREF_INHERITED_GUTS(Class, Super); \ } \ NS_IMETHOD_(MozExternalRefCountType) Release() override { \ NS_IMPL_RELEASE_INHERITED_GUTS(Class, Super); \ } /* * Macro to glue together a QI that starts with an interface table * and segues into an interface map (e.g. it uses singleton classinfo * or tearoffs). */ #define NS_INTERFACE_TABLE_TO_MAP_SEGUE \ if (rv == NS_OK) return rv; \ nsISupports* foundInterface; /////////////////////////////////////////////////////////////////////////////// /** * Macro to generate nsIClassInfo methods for classes which do not have * corresponding nsIFactory implementations. */ #define NS_IMPL_THREADSAFE_CI(_class) \ NS_IMETHODIMP \ _class::GetInterfaces(nsTArray& _array) { \ return NS_CI_INTERFACE_GETTER_NAME(_class)(_array); \ } \ \ NS_IMETHODIMP \ _class::GetScriptableHelper(nsIXPCScriptable** _retval) { \ *_retval = nullptr; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetContractID(nsACString& _contractID) { \ _contractID.SetIsVoid(true); \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetClassDescription(nsACString& _classDescription) { \ _classDescription.SetIsVoid(true); \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetClassID(nsCID** _classID) { \ *_classID = nullptr; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetFlags(uint32_t* _flags) { \ *_flags = nsIClassInfo::THREADSAFE; \ return NS_OK; \ } \ \ NS_IMETHODIMP \ _class::GetClassIDNoAlloc(nsCID* _classIDNoAlloc) { \ return NS_ERROR_NOT_AVAILABLE; \ } #endif