Quelle nsISupportsImpl.h Sprache: C

/* -*- 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(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 <int N>
 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<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.

#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<nsrefcnt> 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 <typename T>
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<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) \
 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 <typename Class, typename Interface>
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 <typename Class, typename Interface>
constexpr const nsIID& kImplementedIID = GetImplementedIID<Class, Interface>();

}

/**
* 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<char*>(static_cast<_interface*>((_class*)0x1000)) - \
 reinterpret_cast<char*>((_class*)0x1000))},

#define NS_INTERFACE_TABLE_ENTRY_AMBIGUOUS(_class, _interface, _implClass) \
 {&mozilla::detail::kImplementedIID<_class, _interface>, \
 int32_t(reinterpret_cast<char*>(static_cast<_interface*>( \
 static_cast<_implClass*>((_class*)0x1000))) - \
 reinterpret_cast<char*>((_class*)0x1000))},

#define NS_INTERFACE_TABLE_END_WITH_PTR(_ptr) \
 { nullptr, 0 } \
 } \
 ; \
 static_assert(std::size(table) > 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_IID(_interface) \
 mozilla::detail::kImplementedIID<std::remove_reference_t<decltype(*this)>, \
 _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 <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"); \
--> --------------------

--> maximum size reached

--> --------------------

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