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Diffstat (limited to 'xpcom/glue/nsISupportsImpl.h')
| -rw-r--r-- | xpcom/glue/nsISupportsImpl.h | 1090 |
1 files changed, 1090 insertions, 0 deletions
diff --git a/xpcom/glue/nsISupportsImpl.h b/xpcom/glue/nsISupportsImpl.h new file mode 100644 index 000000000..26db3c525 --- /dev/null +++ b/xpcom/glue/nsISupportsImpl.h @@ -0,0 +1,1090 @@ +/* -*- 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 "nsISupportsBase.h" +#include "nsISupportsUtils.h" + + +#if !defined(XPCOM_GLUE_AVOID_NSPR) +#include "prthread.h" /* needed for thread-safety checks */ +#endif // !XPCOM_GLUE_AVOID_NSPR + +#include "nsDebug.h" +#include "nsXPCOM.h" +#include "mozilla/Atomics.h" +#include "mozilla/Attributes.h" +#include "mozilla/Assertions.h" +#include "mozilla/Compiler.h" +#include "mozilla/Likely.h" +#include "mozilla/MacroArgs.h" +#include "mozilla/MacroForEach.h" +#include "mozilla/TypeTraits.h" + +#define MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(X) \ + static_assert(!mozilla::IsDestructible<X>::value, \ + "Reference-counted class " #X " should not have a public destructor. " \ + "Make this class's destructor non-public"); + +inline nsISupports* +ToSupports(nsISupports* aSupports) +{ + return aSupports; +} + +inline nsISupports* +ToCanonicalSupports(nsISupports* aSupports) +{ + return nullptr; +} + +//////////////////////////////////////////////////////////////////////////////// +// Macros to help detect thread-safety: + +#ifdef MOZ_THREAD_SAFETY_OWNERSHIP_CHECKS_SUPPORTED + +class nsAutoOwningThread +{ +public: + nsAutoOwningThread() { mThread = PR_GetCurrentThread(); } + void* GetThread() const { return mThread; } + +private: + void* mThread; +}; + +#define NS_DECL_OWNINGTHREAD nsAutoOwningThread _mOwningThread; +#define NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class) \ + NS_CheckThreadSafe(agg->_mOwningThread.GetThread(), #_class " not thread-safe") +#define NS_ASSERT_OWNINGTHREAD(_class) NS_ASSERT_OWNINGTHREAD_AGGREGATE(this, _class) +#else // !DEBUG && !(NIGHTLY_BUILD && !MOZ_PROFILING) + +#define NS_DECL_OWNINGTHREAD /* nothing */ +#define NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class) ((void)0) +#define NS_ASSERT_OWNINGTHREAD(_class) ((void)0) + +#endif // DEBUG || (NIGHTLY_BUILD && !MOZ_PROFILING) + + +// 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)) + +#include "mozilla/TypeTraits.h" +#define MOZ_ASSERT_CLASSNAME(_type) \ + static_assert(mozilla::IsClass<_type>::value, \ + "Token '" #_type "' is not a class type.") + +// 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); \ + 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); \ + 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); \ + 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); \ + 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) + +/* 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),static_cast<nsISupports*>(_p)) + +#define NSCAP_LOG_RELEASE(_c, _p) \ + if (_p) \ + NS_LogCOMPtrRelease((_c), static_cast<nsISupports*>(_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) + +#endif /* NS_BUILD_REFCNT_LOGGING */ + + +// 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: + 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); + } + + 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++() { return ++mValue; } + MOZ_ALWAYS_INLINE nsrefcnt operator--() { return --mValue; } + + MOZ_ALWAYS_INLINE nsrefcnt operator=(nsrefcnt aValue) + { + return (mValue = aValue); + } + MOZ_ALWAYS_INLINE operator nsrefcnt() const { return mValue; } + MOZ_ALWAYS_INLINE nsrefcnt get() const { return mValue; } + + static const bool isThreadSafe = true; +private: + nsrefcnt operator++(int) = delete; + nsrefcnt operator--(int) = delete; + // In theory, RelaseAcquire consistency (but no weaker) is sufficient for + // the counter. Making it weaker could speed up builds on ARM (but not x86), + // but could break pre-existing code that assumes sequential consistency. + 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; \ + typedef mozilla::FalseType HasThreadSafeRefCnt; \ +protected: \ + nsAutoRefCnt mRefCnt; \ + NS_DECL_OWNINGTHREAD \ +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; \ + typedef mozilla::TrueType HasThreadSafeRefCnt; \ +protected: \ + ::mozilla::ThreadSafeAutoRefCnt mRefCnt; \ + NS_DECL_OWNINGTHREAD \ +public: + +#define NS_DECL_CYCLE_COLLECTING_ISUPPORTS \ +public: \ + NS_IMETHOD QueryInterface(REFNSIID aIID, \ + void** aInstancePtr) override; \ + NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override; \ + NS_IMETHOD_(MozExternalRefCountType) Release(void) override; \ + NS_IMETHOD_(void) DeleteCycleCollectable(void); \ + typedef mozilla::FalseType HasThreadSafeRefCnt; \ +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_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_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) \ +public: \ + NS_METHOD_(MozExternalRefCountType) AddRef(void) { \ + NS_IMPL_CC_NATIVE_ADDREF_BODY(_class) \ + } \ + NS_METHOD_(MozExternalRefCountType) Release(void) { \ + NS_IMPL_CC_NATIVE_RELEASE_BODY(_class) \ + } \ + typedef mozilla::FalseType HasThreadSafeRefCnt; \ +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 optional override Mark the AddRef & Release methods as overrides. + */ +#define NS_INLINE_DECL_REFCOUNTING_WITH_DESTROY(_class, _destroy, ...) \ +public: \ + NS_METHOD_(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; \ + } \ + NS_METHOD_(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; \ + } \ + typedef mozilla::FalseType HasThreadSafeRefCnt; \ +protected: \ + nsAutoRefCnt 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 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__) + +#define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, _decl, ...) \ +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) { \ + delete (this); \ + return 0; \ + } \ + return count; \ + } \ + typedef mozilla::TrueType HasThreadSafeRefCnt; \ +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 + */ +#define NS_INLINE_DECL_THREADSAFE_REFCOUNTING(_class, ...) \ +NS_INLINE_DECL_THREADSAFE_REFCOUNTING_META(_class, NS_METHOD_, __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_REFCOUNTING_META(_class, NS_IMETHOD_, __VA_ARGS__) + +/** + * 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_IMETHODIMP_(MozExternalRefCountType) _class::AddRef(void) \ +{ \ + MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class) \ + MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt"); \ + if (!mRefCnt.isThreadSafe) \ + NS_ASSERT_OWNINGTHREAD(_class); \ + nsrefcnt count = ++mRefCnt; \ + NS_LOG_ADDREF(this, count, #_class, sizeof(*this)); \ + return count; \ +} + +/** + * 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) \ + NS_PRECONDITION(_aggregator, "null aggregator"); \ + return (_aggregator)->AddRef(); \ +} + +/** + * 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 _destroy A statement that is executed when the object's + * refcount drops to zero. + * + * For example, + * + * NS_IMPL_RELEASE_WITH_DESTROY(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_RELEASE_WITH_DESTROY(_class, _destroy) \ +NS_IMETHODIMP_(MozExternalRefCountType) _class::Release(void) \ +{ \ + MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release"); \ + if (!mRefCnt.isThreadSafe) \ + NS_ASSERT_OWNINGTHREAD(_class); \ + nsrefcnt count = --mRefCnt; \ + NS_LOG_RELEASE(this, count, #_class); \ + if (count == 0) { \ + mRefCnt = 1; /* stabilize */ \ + _destroy; \ + return 0; \ + } \ + return count; \ +} + +/** + * 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)) + +/** + * 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) \ +{ \ + NS_PRECONDITION(_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; \ +} + +/////////////////////////////////////////////////////////////////////////////// + +/** + * 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 + +#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_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, ...) \ + MOZ_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__); \ + 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. + * + * Note that I didn't make these inlined because they're virtual methods. + */ + +#define NS_IMPL_ADDREF_INHERITED(Class, Super) \ +NS_IMETHODIMP_(MozExternalRefCountType) Class::AddRef(void) \ +{ \ + MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(Class) \ + nsrefcnt r = Super::AddRef(); \ + NS_LOG_ADDREF(this, r, #Class, sizeof(*this)); \ + return r; \ +} + +#define NS_IMPL_RELEASE_INHERITED(Class, Super) \ +NS_IMETHODIMP_(MozExternalRefCountType) Class::Release(void) \ +{ \ + nsrefcnt r = Super::Release(); \ + NS_LOG_RELEASE(this, r, #Class); \ + return r; \ +} + +/** + * 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, ...) \ + MOZ_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__); \ + 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__) + +#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) + +/* + * 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; + + +/////////////////////////////////////////////////////////////////////////////// +/** + * + * Threadsafe implementations of the ISupports convenience macros. + * + * @note These are not available when linking against the standalone glue, + * because the implementation requires PR_ symbols. + */ +#define NS_INTERFACE_MAP_END_THREADSAFE NS_IMPL_QUERY_TAIL_GUTS + +/** + * Macro to generate nsIClassInfo methods for classes which do not have + * corresponding nsIFactory implementations. + */ +#define NS_IMPL_THREADSAFE_CI(_class) \ +NS_IMETHODIMP \ +_class::GetInterfaces(uint32_t* _count, nsIID*** _array) \ +{ \ + return NS_CI_INTERFACE_GETTER_NAME(_class)(_count, _array); \ +} \ + \ +NS_IMETHODIMP \ +_class::GetScriptableHelper(nsIXPCScriptable** _retval) \ +{ \ + *_retval = nullptr; \ + return NS_OK; \ +} \ + \ +NS_IMETHODIMP \ +_class::GetContractID(char** _contractID) \ +{ \ + *_contractID = nullptr; \ + return NS_OK; \ +} \ + \ +NS_IMETHODIMP \ +_class::GetClassDescription(char** _classDescription) \ +{ \ + *_classDescription = nullptr; \ + 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 |