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Diffstat (limited to '')
| -rw-r--r-- | xpcom/base/nsISupportsImpl.h | 1539 |
1 files changed, 1539 insertions, 0 deletions
diff --git a/xpcom/base/nsISupportsImpl.h b/xpcom/base/nsISupportsImpl.h new file mode 100644 index 0000000000..6a232daae9 --- /dev/null +++ b/xpcom/base/nsISupportsImpl.h @@ -0,0 +1,1539 @@ +/* -*- 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 <atomic> +#include <type_traits> +#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<X>, \ + "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 <int N> + 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(); + + // 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 <int N> + void AssertOwnership(const char (&aMsg)[N]) const { + AssertCurrentThreadOwnsMe(aMsg); + } + + bool IsCurrentThread() const; + + private: + void AssertCurrentThreadOwnsMe(const char* aMsg) const; + + 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<nsISupports, _type>::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<void*>, so they don't + * do anything useful if we don't have dynamic_cast<void*>. + * 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. + +#define NS_NUMBER_OF_FLAGS_IN_REFCNT 2 +#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; + + template <Suspect suspect = NS_CycleCollectorSuspect3> + MOZ_ALWAYS_INLINE uintptr_t incr(nsISupports* aOwner) { + return incr<suspect>(aOwner, nullptr); + } + + template <Suspect suspect = NS_CycleCollectorSuspect3> + 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); + suspect(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; + } + + template <Suspect suspect = NS_CycleCollectorSuspect3> + MOZ_ALWAYS_INLINE uintptr_t decr(nsISupports* aOwner, + bool* aShouldDelete = nullptr) { + return decr<suspect>(aOwner, nullptr, aShouldDelete); + } + + template <Suspect suspect = NS_CycleCollectorSuspect3> + 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'! + suspect(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); + } + + 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<nsrefcnt> mValue; +}; + +} // 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_FINAL_DELETECYCLECOLLECTABLE \ + NS_DECL_CYCLE_COLLECTING_ISUPPORTS_META(override) \ + NS_IMETHOD_(void) DeleteCycleCollectable(void) final; \ + \ + 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<void*>(this), \ + _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ + NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ + return count; + +#define NS_IMPL_CC_MAIN_THREAD_ONLY_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<NS_CycleCollectorSuspectUsingNursery>( \ + static_cast<void*>(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<void*>(this), \ + _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ + NS_LOG_RELEASE(this, count, #_class); \ + return count; + +#define NS_IMPL_CC_MAIN_THREAD_ONLY_NATIVE_RELEASE_BODY(_class) \ + MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ + NS_ASSERT_OWNINGTHREAD(_class); \ + nsrefcnt count = mRefCnt.decr<NS_CycleCollectorSuspectUsingNursery>( \ + static_cast<void*>(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<void*>(this), \ + _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant(), \ + &shouldDelete); \ + NS_LOG_RELEASE(this, count, #_class); \ + if (count == 0) { \ + mRefCnt.incr(static_cast<void*>(this), \ + _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()); \ + _last; \ + mRefCnt.decr(static_cast<void*>(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: + +#define NS_INLINE_DECL_MAIN_THREAD_ONLY_CYCLE_COLLECTING_NATIVE_REFCOUNTING( \ + _class) \ + public: \ + NS_METHOD_(MozExternalRefCountType) \ + AddRef(void){NS_IMPL_CC_MAIN_THREAD_ONLY_NATIVE_ADDREF_BODY( \ + _class)} NS_METHOD_(MozExternalRefCountType) Release(void) { \ + NS_IMPL_CC_MAIN_THREAD_ONLY_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 <i>_class</i>. + * + * @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 <i>_class</i>. + * + * @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 <i>_class</i>. + * + * @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 <i>_class</i> 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 <i>_class</i> 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 <i>_class</i> 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 <i>_class</i> 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 <i>_class</i> + * @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 <i>_class</i> + * @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 <i>_class</i> + * 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 + * <i>_class</i>. + * @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 <i>_class</i> + * @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 <i>_class</i> + * 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_MAIN_THREAD_ONLY_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<NS_CycleCollectorSuspectUsingNursery>(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; } + +#define NS_IMPL_MAIN_THREAD_ONLY_CYCLE_COLLECTING_RELEASE(_class) \ + 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<NS_CycleCollectorSuspectUsingNursery>(base); \ + NS_LOG_RELEASE(this, count, #_class); \ + return count; \ + } \ + NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { 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_MAIN_THREAD_ONLY_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<NS_CycleCollectorSuspectUsingNursery>( \ + base, &shouldDelete); \ + NS_LOG_RELEASE(this, count, #_class); \ + if (count == 0) { \ + mRefCnt.incr<NS_CycleCollectorSuspectUsingNursery>(base); \ + _last; \ + mRefCnt.decr<NS_CycleCollectorSuspectUsingNursery>(base); \ + if (shouldDelete) { \ + mRefCnt.stabilizeForDeletion(); \ + DeleteCycleCollectable(); \ + } \ + } \ + return count; \ + } \ + NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { delete this; } + +// _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_MAIN_THREAD_ONLY_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<NS_CycleCollectorSuspectUsingNursery>( \ + base, &shouldDelete); \ + NS_LOG_RELEASE(this, count, #_class); \ + if (count == 0) { \ + mRefCnt.incr<NS_CycleCollectorSuspectUsingNursery>(base); \ + _last; \ + mRefCnt.decr<NS_CycleCollectorSuspectUsingNursery>(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; } + +// _LAST_RELEASE can be useful when certain resources should be released +// as soon as we know the object will be deleted. +#define NS_IMPL_MAIN_THREAD_ONLY_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<NS_CycleCollectorSuspectUsingNursery>( \ + base, &shouldDelete); \ + NS_LOG_RELEASE(this, count, #_class); \ + if (count == 0) { \ + mRefCnt.incr<NS_CycleCollectorSuspectUsingNursery>(base); \ + _last; \ + mRefCnt.decr<NS_CycleCollectorSuspectUsingNursery>(base); \ + if (shouldDelete) { \ + mRefCnt.stabilizeForDeletion(); \ + DeleteCycleCollectable(); \ + } \ + } \ + return count; \ + } \ + NS_IMETHODIMP_(void) _class::DeleteCycleCollectable(void) { _destroy; } + +/////////////////////////////////////////////////////////////////////////////// + +/** + * 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) \ + {&NS_GET_IID(_interface), \ + int32_t( \ + reinterpret_cast<char*>(static_cast<_interface*>((_class*)0x1000)) - \ + reinterpret_cast<char*>((_class*)0x1000))}, + +#define NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(_class, _interface, _implClass) \ + {&NS_GET_IID(_interface), \ + int32_t(reinterpret_cast<char*>(static_cast<_interface*>( \ + static_cast<_implClass*>((_class*)0x1000))) - \ + reinterpret_cast<char*>((_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<void*>(_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(_interface) \ + if (aIID.Equals(NS_GET_IID(_interface))) \ + foundInterface = static_cast<_interface*>(this); \ + else + +#define NS_IMPL_QUERY_BODY_CONDITIONAL(_interface, condition) \ + if ((condition) && aIID.Equals(NS_GET_IID(_interface))) \ + foundInterface = static_cast<_interface*>(this); \ + else + +#define NS_IMPL_QUERY_BODY_AMBIGUOUS(_interface, _implClass) \ + if (aIID.Equals(NS_GET_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_GET_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_GET_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 <typename T> +constexpr bool ShouldLogInheritedRefcnt = + !std::is_convertible_v<T*, Runnable*> && + !std::is_base_of_v<SupportsThreadSafeWeakPtrBase, T>; +} +} // 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<Class>) { \ + 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<Class>) { \ + 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<nsIID>& _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 |