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gecko-dev/xpcom/base/nsISupportsImpl.h

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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/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 <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); \
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))},
/*
* XXX: we want to use mozilla::ArrayLength (or equivalent,
* MOZ_ARRAY_LENGTH) in this condition, but some versions of GCC don't
* see that the static_assert condition is actually constant in those
* cases, even with constexpr support (?).
*/
#define NS_INTERFACE_TABLE_END_WITH_PTR(_ptr) \
{ nullptr, 0 } \
} \
; \
static_assert((sizeof(table) / sizeof(table[0])) > 1, \
"need at least 1 interface"); \
rv = NS_TableDrivenQI(static_cast<void*>(_ptr), aIID, aInstancePtr, table);
#define NS_INTERFACE_TABLE_END \
NS_INTERFACE_TABLE_END_WITH_PTR \
(this)
#define NS_INTERFACE_TABLE_TAIL \
return rv; \
}
#define NS_INTERFACE_TABLE_TAIL_INHERITING(_baseclass) \
if (NS_SUCCEEDED(rv)) return rv; \
return _baseclass::QueryInterface(aIID, aInstancePtr); \
}
#define NS_INTERFACE_TABLE_TAIL_USING_AGGREGATOR(_aggregator) \
if (NS_SUCCEEDED(rv)) return rv; \
NS_ASSERTION(_aggregator, "null aggregator"); \
return _aggregator->QueryInterface(aIID, aInstancePtr) \
}
/**
* This implements query interface with two assumptions: First, the
* class in question implements nsISupports and its own interface and
* nothing else. Second, the implementation of the class's primary
* inheritance chain leads to its own interface.
*
* @param _class The name of the class implementing the method
* @param _classiiddef The name of the #define symbol that defines the IID
* for the class (e.g. NS_ISUPPORTS_IID)
*/
#define NS_IMPL_QUERY_HEAD(_class) \
NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) { \
NS_ASSERTION(aInstancePtr, \
"QueryInterface requires a non-NULL destination!"); \
nsISupports* foundInterface;
#define NS_IMPL_QUERY_BODY_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
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