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/* -*- 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/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);

  constexpr nsCycleCollectingAutoRefCnt() : mRefCntAndFlags(0) {}

  constexpr 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:

  constexpr nsAutoRefCnt() : mValue(0) {}

  constexpr 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:

  constexpr ThreadSafeAutoRefCnt() : mValue(0) {}

  constexpr 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_METHOD_(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()); \

  if (count == 0) {                                                           \

    NS_CycleCollectableHasRefCntZero();                                       \

  }                                                                           \

  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());  \

      NS_CycleCollectableHasRefCntZero();                                      \

      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 <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_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);                                     \

    if (count == 0) {                                                        \

      NS_CycleCollectableHasRefCntZero();                                    \

    }                                                                        \

    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);                                                    \

      NS_CycleCollectableHasRefCntZero();                                    \

      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);                                                    \

      NS_CycleCollectableHasRefCntZero();                                    \

      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();                                                \

      }                                                                      \

      NS_CycleCollectableHasRefCntZero();                                    \

      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_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"); \

  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