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-rw-r--r--dom/base/nsWrapperCache.h646
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diff --git a/dom/base/nsWrapperCache.h b/dom/base/nsWrapperCache.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/. */
+
+#ifndef nsWrapperCache_h___
+#define nsWrapperCache_h___
+
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ServoUtils.h"
+#include "mozilla/RustCell.h"
+#include "js/HeapAPI.h"
+#include "js/TracingAPI.h"
+#include "js/TypeDecls.h"
+#include "nsISupports.h"
+#include "nsISupportsUtils.h"
+#include <type_traits>
+
+namespace mozilla::dom {
+class ContentProcessMessageManager;
+class InProcessBrowserChildMessageManager;
+class BrowserChildMessageManager;
+} // namespace mozilla::dom
+class SandboxPrivate;
+class nsWindowRoot;
+
+#define NS_WRAPPERCACHE_IID \
+ { \
+ 0x6f3179a1, 0x36f7, 0x4a5c, { \
+ 0x8c, 0xf1, 0xad, 0xc8, 0x7c, 0xde, 0x3e, 0x87 \
+ } \
+ }
+
+// There are two sets of flags used by DOM nodes. One comes from reusing the
+// remaining bits of the inherited nsWrapperCache flags (mFlags), and another is
+// exclusive to nsINode (mBoolFlags).
+//
+// Both sets of flags are 32 bits. On 64-bit platforms, this can cause two
+// wasted 32-bit fields due to alignment requirements. Some compilers are
+// smart enough to coalesce the fields if we make mBoolFlags the first member
+// of nsINode, but others (such as MSVC) are not.
+//
+// So we just store mBoolFlags directly on nsWrapperCache on 64-bit platforms.
+// This may waste space for some other nsWrapperCache-derived objects that have
+// a 32-bit field as their first member, but those objects are unlikely to be as
+// numerous or performance-critical as DOM nodes.
+#ifdef HAVE_64BIT_BUILD
+static_assert(sizeof(void*) == 8, "These architectures should be 64-bit");
+# define BOOL_FLAGS_ON_WRAPPER_CACHE
+#else
+static_assert(sizeof(void*) == 4, "Only support 32-bit and 64-bit");
+#endif
+
+/**
+ * Class to store the wrapper for an object. This can only be used with objects
+ * that only have one non-security wrapper at a time (for an XPCWrappedNative
+ * this is usually ensured by setting an explicit parent in the PreCreate hook
+ * for the class).
+ *
+ * An instance of nsWrapperCache can be gotten from an object that implements
+ * a wrapper cache by calling QueryInterface on it. Note that this breaks XPCOM
+ * rules a bit (this object doesn't derive from nsISupports).
+ *
+ * The cache can store objects other than wrappers. We allow wrappers to use a
+ * separate JSObject to store their state (mostly expandos). If the wrapper is
+ * collected and we want to preserve this state we actually store the state
+ * object in the cache.
+ *
+ * The cache can store 3 types of objects: a DOM binding object (regular JS
+ * object or proxy), an nsOuterWindowProxy or an XPCWrappedNative wrapper.
+ *
+ * The finalizer for the wrapper clears the cache.
+ *
+ * A compacting GC can move the wrapper object. Pointers to moved objects are
+ * usually found and updated by tracing the heap, however non-preserved wrappers
+ * are weak references and are not traced, so another approach is
+ * necessary. Instead a class hook (objectMovedOp) is provided that is called
+ * when an object is moved and is responsible for ensuring pointers are
+ * updated. It does this by calling UpdateWrapper() on the wrapper
+ * cache. SetWrapper() asserts that the hook is implemented for any wrapper set.
+ *
+ * A number of the methods are implemented in nsWrapperCacheInlines.h because we
+ * have to include some JS headers that don't play nicely with the rest of the
+ * codebase. Include nsWrapperCacheInlines.h if you need to call those methods.
+ */
+
+class JS_HAZ_ROOTED nsWrapperCache {
+ public:
+ NS_DECLARE_STATIC_IID_ACCESSOR(NS_WRAPPERCACHE_IID)
+
+ nsWrapperCache() = default;
+ ~nsWrapperCache() {
+ // Preserved wrappers should never end up getting cleared, but this can
+ // happen during shutdown when a leaked wrapper object is finalized, causing
+ // its wrapper to be cleared.
+ MOZ_ASSERT(!PreservingWrapper() || js::RuntimeIsBeingDestroyed(),
+ "Destroying cache with a preserved wrapper!");
+ }
+
+ /**
+ * Get the cached wrapper.
+ *
+ * This getter clears the gray bit before handing out the JSObject which means
+ * that the object is guaranteed to be kept alive past the next CC.
+ */
+ JSObject* GetWrapper() const;
+
+ /**
+ * Get the cached wrapper.
+ *
+ * This getter does not change the color of the JSObject meaning that the
+ * object returned is not guaranteed to be kept alive past the next CC.
+ *
+ * This should only be called if you are certain that the return value won't
+ * be passed into a JSAPI function and that it won't be stored without being
+ * rooted (or otherwise signaling the stored value to the CC).
+ */
+ JSObject* GetWrapperPreserveColor() const;
+
+ /**
+ * Get the cached wrapper.
+ *
+ * This getter does not check whether the wrapper is dead and in the process
+ * of being finalized.
+ *
+ * This should only be called if you really need to see the raw contents of
+ * this cache, for example as part of finalization. Don't store the result
+ * anywhere or pass it into JSAPI functions that may cause the value to
+ * escape.
+ */
+ JSObject* GetWrapperMaybeDead() const { return mWrapper; }
+
+#ifdef DEBUG
+ private:
+ static bool HasJSObjectMovedOp(JSObject* aWrapper);
+
+ static void AssertUpdatedWrapperZone(const JSObject* aNewObject,
+ const JSObject* aOldObject);
+
+ public:
+#endif
+
+ void SetWrapper(JSObject* aWrapper) {
+ MOZ_ASSERT(!PreservingWrapper(), "Clearing a preserved wrapper!");
+ MOZ_ASSERT(aWrapper, "Use ClearWrapper!");
+ MOZ_ASSERT(HasJSObjectMovedOp(aWrapper),
+ "Object has not provided the hook to update the wrapper if it "
+ "is moved");
+
+ SetWrapperJSObject(aWrapper);
+ }
+
+ /**
+ * Clear the cache.
+ */
+ void ClearWrapper() {
+ // Preserved wrappers should never end up getting cleared, but this can
+ // happen during shutdown when a leaked wrapper object is finalized, causing
+ // its wrapper to be cleared.
+ MOZ_ASSERT(!PreservingWrapper() || js::RuntimeIsBeingDestroyed(),
+ "Clearing a preserved wrapper!");
+ SetWrapperJSObject(nullptr);
+ }
+
+ /**
+ * Clear the cache if it still contains a specific wrapper object. This should
+ * be called from the finalizer for the wrapper.
+ */
+ void ClearWrapper(JSObject* obj) {
+ if (obj == mWrapper) {
+ ClearWrapper();
+ }
+ }
+
+ /**
+ * Update the wrapper when the object moves between globals.
+ */
+ template <typename T>
+ void UpdateWrapperForNewGlobal(T* aScriptObjectHolder, JSObject* aNewWrapper);
+
+ /**
+ * Update the wrapper if the object it contains is moved.
+ *
+ * This method must be called from the objectMovedOp class extension hook for
+ * any wrapper cached object.
+ */
+ void UpdateWrapper(JSObject* aNewObject, const JSObject* aOldObject) {
+#ifdef DEBUG
+ AssertUpdatedWrapperZone(aNewObject, aOldObject);
+#endif
+ if (mWrapper) {
+ MOZ_ASSERT(mWrapper == aOldObject);
+ mWrapper = aNewObject;
+ }
+ }
+
+ bool PreservingWrapper() const {
+ return HasWrapperFlag(WRAPPER_BIT_PRESERVED);
+ }
+
+ /**
+ * Wrap the object corresponding to this wrapper cache. If non-null is
+ * returned, the object has already been stored in the wrapper cache.
+ */
+ virtual JSObject* WrapObject(JSContext* cx,
+ JS::Handle<JSObject*> aGivenProto) = 0;
+
+ /**
+ * Returns true if the object has a wrapper that is known live from the point
+ * of view of cycle collection.
+ */
+ bool HasKnownLiveWrapper() const;
+
+ /**
+ * Returns true if the object has a known-live wrapper (from the CC point of
+ * view) and all the GC things it is keeping alive are already known-live from
+ * CC's point of view.
+ */
+ bool HasKnownLiveWrapperAndDoesNotNeedTracing(nsISupports* aThis);
+
+ bool HasNothingToTrace(nsISupports* aThis);
+
+ /**
+ * Mark our wrapper, if any, as live as far as the CC is concerned.
+ */
+ void MarkWrapperLive();
+
+ // Only meant to be called by code that preserves a wrapper.
+ void SetPreservingWrapper(bool aPreserve) {
+ if (aPreserve) {
+ SetWrapperFlags(WRAPPER_BIT_PRESERVED);
+ } else {
+ UnsetWrapperFlags(WRAPPER_BIT_PRESERVED);
+ }
+ }
+
+ void TraceWrapper(const TraceCallbacks& aCallbacks, void* aClosure) {
+ if (PreservingWrapper() && mWrapper) {
+ aCallbacks.Trace(this, "Preserved wrapper", aClosure);
+ }
+ }
+
+ /*
+ * The following methods for getting and manipulating flags allow the unused
+ * bits of mFlags to be used by derived classes.
+ */
+
+ using FlagsType = uint32_t;
+
+ FlagsType GetFlags() const {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_ASSERT(!mozilla::IsInServoTraversal());
+ return mFlags.Get() & ~kWrapperFlagsMask;
+ }
+
+ // This can be called from stylo threads too, so it needs to be atomic, as
+ // this value may be mutated from multiple threads during servo traversal from
+ // rust.
+ bool HasFlag(FlagsType aFlag) const {
+ MOZ_ASSERT((aFlag & kWrapperFlagsMask) == 0, "Bad flag mask");
+ return __atomic_load_n(mFlags.AsPtr(), __ATOMIC_RELAXED) & aFlag;
+ }
+
+ // Identical to HasFlag, but more explicit about its handling of multiple
+ // flags. This can be called from stylo threads too.
+ bool HasAnyOfFlags(FlagsType aFlags) const { return HasFlag(aFlags); }
+
+ // This can also be called from stylo, in the sequential part of the
+ // traversal, though it's probably not worth differentiating them for the
+ // purposes of assertions.
+ bool HasAllFlags(FlagsType aFlags) const {
+ MOZ_ASSERT((aFlags & kWrapperFlagsMask) == 0, "Bad flag mask");
+ return (__atomic_load_n(mFlags.AsPtr(), __ATOMIC_RELAXED) & aFlags) ==
+ aFlags;
+ }
+
+ void SetFlags(FlagsType aFlagsToSet) {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_ASSERT((aFlagsToSet & kWrapperFlagsMask) == 0, "Bad flag mask");
+ mFlags.Set(mFlags.Get() | aFlagsToSet);
+ }
+
+ void UnsetFlags(FlagsType aFlagsToUnset) {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_ASSERT((aFlagsToUnset & kWrapperFlagsMask) == 0, "Bad flag mask");
+ mFlags.Set(mFlags.Get() & ~aFlagsToUnset);
+ }
+
+ void PreserveWrapper(nsISupports* aScriptObjectHolder) {
+ if (PreservingWrapper()) {
+ return;
+ }
+
+ nsISupports* ccISupports;
+ aScriptObjectHolder->QueryInterface(NS_GET_IID(nsCycleCollectionISupports),
+ reinterpret_cast<void**>(&ccISupports));
+ MOZ_ASSERT(ccISupports);
+
+ nsXPCOMCycleCollectionParticipant* participant;
+ CallQueryInterface(ccISupports, &participant);
+ PreserveWrapper(ccISupports, participant);
+ }
+
+ void PreserveWrapper(void* aScriptObjectHolder,
+ nsScriptObjectTracer* aTracer) {
+ if (PreservingWrapper()) {
+ return;
+ }
+
+ JSObject* wrapper = GetWrapper(); // Read barrier for incremental GC.
+ HoldJSObjects(aScriptObjectHolder, aTracer, JS::GetObjectZone(wrapper));
+ SetPreservingWrapper(true);
+#ifdef DEBUG
+ // Make sure the cycle collector will be able to traverse to the wrapper.
+ CheckCCWrapperTraversal(aScriptObjectHolder, aTracer);
+#endif
+ }
+
+ void ReleaseWrapper(void* aScriptObjectHolder);
+
+ void TraceWrapper(JSTracer* aTrc, const char* name) {
+ if (mWrapper) {
+ js::UnsafeTraceManuallyBarrieredEdge(aTrc, &mWrapper, name);
+ }
+ }
+
+ protected:
+ void PoisonWrapper() {
+ if (mWrapper) {
+ // Set the pointer to a value that will cause a crash if it is
+ // dereferenced.
+ mWrapper = reinterpret_cast<JSObject*>(1);
+ }
+ }
+
+ private:
+ void SetWrapperJSObject(JSObject* aWrapper);
+
+ // We'd like to assert that these aren't used from servo threads, but we don't
+ // have a great way to do that because:
+ // * We can't just assert that they get used on the main thread, because
+ // these are used from workers.
+ // * We can't just assert that they aren't used when IsInServoTraversal(),
+ // because the traversal has a sequential, main-thread-only phase, where we
+ // run animations that can fiddle with JS promises.
+ FlagsType GetWrapperFlags() const { return mFlags.Get() & kWrapperFlagsMask; }
+
+ bool HasWrapperFlag(FlagsType aFlag) const {
+ MOZ_ASSERT((aFlag & ~kWrapperFlagsMask) == 0, "Bad wrapper flag bits");
+ return !!(mFlags.Get() & aFlag);
+ }
+
+ void SetWrapperFlags(FlagsType aFlagsToSet) {
+ MOZ_ASSERT((aFlagsToSet & ~kWrapperFlagsMask) == 0,
+ "Bad wrapper flag bits");
+ mFlags.Set(mFlags.Get() | aFlagsToSet);
+ }
+
+ void UnsetWrapperFlags(FlagsType aFlagsToUnset) {
+ MOZ_ASSERT((aFlagsToUnset & ~kWrapperFlagsMask) == 0,
+ "Bad wrapper flag bits");
+ mFlags.Set(mFlags.Get() & ~aFlagsToUnset);
+ }
+
+ void HoldJSObjects(void* aScriptObjectHolder, nsScriptObjectTracer* aTracer,
+ JS::Zone* aZone);
+
+#ifdef DEBUG
+ public:
+ void CheckCCWrapperTraversal(void* aScriptObjectHolder,
+ nsScriptObjectTracer* aTracer);
+
+ private:
+#endif // DEBUG
+
+ /**
+ * If this bit is set then we're preserving the wrapper, which in effect ties
+ * the lifetime of the JS object stored in the cache to the lifetime of the
+ * native object. We rely on the cycle collector to break the cycle that this
+ * causes between the native object and the JS object, so it is important that
+ * any native object that supports preserving of its wrapper
+ * traces/traverses/unlinks the cached JS object (see
+ * NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER and
+ * NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER).
+ */
+ enum { WRAPPER_BIT_PRESERVED = 1 << 0 };
+
+ enum { kWrapperFlagsMask = WRAPPER_BIT_PRESERVED };
+
+ JSObject* mWrapper = nullptr;
+
+ // Rust code needs to read and write some flags atomically, but we don't want
+ // to make the wrapper flags atomic whole-sale because main-thread code would
+ // become more expensive (loads wouldn't change, but flag setting /
+ // unsetting could become slower enough to be noticeable). Making this an
+ // Atomic whole-sale needs more measuring.
+ //
+ // In order to not mess with aliasing rules the type should not be frozen, so
+ // we use a RustCell, which contains an UnsafeCell internally. See also the
+ // handling of ServoData (though that's a bit different).
+ mozilla::RustCell<FlagsType> mFlags{0};
+
+ protected:
+#ifdef BOOL_FLAGS_ON_WRAPPER_CACHE
+ uint32_t mBoolFlags = 0;
+#endif
+};
+
+enum { WRAPPER_CACHE_FLAGS_BITS_USED = 1 };
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsWrapperCache, NS_WRAPPERCACHE_IID)
+
+#define NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY \
+ if (aIID.Equals(NS_GET_IID(nsWrapperCache))) { \
+ *aInstancePtr = static_cast<nsWrapperCache*>(this); \
+ return NS_OK; \
+ }
+
+#define NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY \
+ NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY \
+ else
+
+// Cycle collector macros for wrapper caches.
+//
+// The NS_DECL_*WRAPPERCACHE_* macros make it easier to mark classes as holding
+// just a single pointer to a JS value. That information is then used for
+// certain GC optimizations.
+
+#define NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS_AMBIGUOUS(_class, _base) \
+ class NS_CYCLE_COLLECTION_INNERCLASS \
+ : public nsXPCOMCycleCollectionParticipant { \
+ public: \
+ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS(Flags aFlags = 0) \
+ : nsXPCOMCycleCollectionParticipant(aFlags | \
+ FlagMaybeSingleZoneJSHolder) {} \
+ \
+ private: \
+ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \
+ NS_IMETHOD_(void) \
+ Trace(void* p, const TraceCallbacks& cb, void* closure) override; \
+ NS_IMETHOD_(void) \
+ TraceWrapper(void* aPtr, const TraceCallbacks& aCb, void* aClosure) final; \
+ NS_IMPL_GET_XPCOM_CYCLE_COLLECTION_PARTICIPANT(_class) \
+ }; \
+ NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL(_class) \
+ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; \
+ NOT_INHERITED_CANT_OVERRIDE
+
+#define NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS_AMBIGUOUS(_class, _class)
+
+#define NS_DECL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS_INHERITED(_class, \
+ _base_class) \
+ class NS_CYCLE_COLLECTION_INNERCLASS \
+ : public NS_CYCLE_COLLECTION_CLASSNAME(_base_class) { \
+ public: \
+ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS(Flags aFlags) \
+ : NS_CYCLE_COLLECTION_CLASSNAME(_base_class)( \
+ aFlags | FlagMaybeSingleZoneJSHolder) {} \
+ \
+ private: \
+ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY(_class, _base_class) \
+ NS_IMETHOD_(void) \
+ Trace(void* p, const TraceCallbacks& cb, void* closure) override; \
+ NS_IMETHOD_(void) \
+ TraceWrapper(void* aPtr, const TraceCallbacks& aCb, void* aClosure) final; \
+ NS_IMPL_GET_XPCOM_CYCLE_COLLECTION_PARTICIPANT(_class) \
+ }; \
+ NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL_INHERITED(_class) \
+ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME;
+
+#define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS_AMBIGUOUS( \
+ _class, _base) \
+ class NS_CYCLE_COLLECTION_INNERCLASS \
+ : public nsXPCOMCycleCollectionParticipant { \
+ public: \
+ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS(Flags aFlags) \
+ : nsXPCOMCycleCollectionParticipant(aFlags | FlagMightSkip | \
+ FlagMaybeSingleZoneJSHolder) {} \
+ \
+ private: \
+ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \
+ NS_IMETHOD_(void) \
+ Trace(void* p, const TraceCallbacks& cb, void* closure) override; \
+ NS_IMETHOD_(void) \
+ TraceWrapper(void* aPtr, const TraceCallbacks& aCb, void* aClosure) final; \
+ NS_IMETHOD_(bool) CanSkipReal(void* p, bool aRemovingAllowed) override; \
+ NS_IMETHOD_(bool) CanSkipInCCReal(void* p) override; \
+ NS_IMETHOD_(bool) CanSkipThisReal(void* p) override; \
+ NS_IMPL_GET_XPCOM_CYCLE_COLLECTION_PARTICIPANT(_class) \
+ }; \
+ NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL(_class) \
+ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; \
+ NOT_INHERITED_CANT_OVERRIDE
+
+#define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS(_class) \
+ NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS_AMBIGUOUS(_class, \
+ _class)
+
+#define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS_INHERITED( \
+ _class, _base_class) \
+ class NS_CYCLE_COLLECTION_INNERCLASS \
+ : public NS_CYCLE_COLLECTION_CLASSNAME(_base_class) { \
+ public: \
+ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS(Flags aFlags = 0) \
+ : NS_CYCLE_COLLECTION_CLASSNAME(_base_class)( \
+ aFlags | FlagMightSkip | FlagMaybeSingleZoneJSHolder) {} \
+ \
+ private: \
+ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base_class) \
+ NS_IMETHOD_(void) \
+ Trace(void* p, const TraceCallbacks& cb, void* closure) override; \
+ NS_IMETHOD_(void) \
+ TraceWrapper(void* aPtr, const TraceCallbacks& aCb, void* aClosure) final; \
+ NS_IMETHOD_(bool) CanSkipReal(void* p, bool aRemovingAllowed) override; \
+ NS_IMETHOD_(bool) CanSkipInCCReal(void* p) override; \
+ NS_IMETHOD_(bool) CanSkipThisReal(void* p) override; \
+ NS_IMPL_GET_XPCOM_CYCLE_COLLECTION_PARTICIPANT(_class) \
+ }; \
+ NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL_INHERITED(_class) \
+ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME;
+
+#define NS_DECL_CYCLE_COLLECTION_NATIVE_WRAPPERCACHE_CLASS(_class) \
+ void DeleteCycleCollectable(void) { delete this; } \
+ class NS_CYCLE_COLLECTION_INNERCLASS : public nsScriptObjectTracer { \
+ public: \
+ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS(Flags aFlags = 0) \
+ : nsScriptObjectTracer(aFlags | FlagMaybeSingleZoneJSHolder) {} \
+ \
+ private: \
+ NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS_BODY(_class) \
+ NS_IMETHOD_(void) \
+ Trace(void* p, const TraceCallbacks& cb, void* closure) override; \
+ NS_IMETHOD_(void) \
+ TraceWrapper(void* aPtr, const TraceCallbacks& aCb, void* aClosure) final; \
+ static constexpr nsScriptObjectTracer* GetParticipant() { \
+ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \
+ } \
+ }; \
+ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME;
+
+#define NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER \
+ tmp->TraceWrapper(aCallbacks, aClosure);
+
+#define NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ tmp->ReleaseWrapper(p);
+
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ static_assert(std::is_base_of<nsWrapperCache, _class>::value, \
+ "Class should inherit nsWrapperCache"); \
+ NS_IMPL_CYCLE_COLLECTION_SINGLE_ZONE_SCRIPT_HOLDER_CLASS(_class) \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(_class) \
+ TraceWrapper(p, aCallbacks, aClosure); \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_END \
+ void NS_CYCLE_COLLECTION_CLASSNAME(_class)::TraceWrapper( \
+ void* p, const TraceCallbacks& aCallbacks, void* aClosure) { \
+ _class* tmp = DowncastCCParticipant<_class>(p); \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER \
+ }
+
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_0(_class) \
+ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(_class, ...) \
+ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WEAK(_class, ...) \
+ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_REFERENCE \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WEAK_PTR(_class, ...) \
+ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_PTR \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(_class) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+// This is used for wrapper cached classes that inherit from cycle
+// collected non-wrapper cached classes.
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_INHERITED(_class, _base, ...) \
+ static_assert(!std::is_base_of<nsWrapperCache, _base>::value, \
+ "Base class should not inherit nsWrapperCache"); \
+ NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(_class) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(_class, _base) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(_class, _base) \
+ /* Assert somewhere, in this case in the traverse method, that the */ \
+ /* parent isn't a single zone holder*/ \
+ MOZ_ASSERT(!_base::NS_CYCLE_COLLECTION_INNERNAME.IsSingleZoneJSHolder()); \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(__VA_ARGS__) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+// if NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WITH_JS_MEMBERS is used to implement
+// a wrappercache class, one needs to use
+// NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS and its variants in the class
+// declaration.
+#define NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WITH_JS_MEMBERS( \
+ class_, native_members_, js_members_) \
+ static_assert(std::is_base_of<nsWrapperCache, class_>::value, \
+ "Class should inherit nsWrapperCache"); \
+ NS_IMPL_CYCLE_COLLECTION_CLASS(class_) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(class_) \
+ using ::ImplCycleCollectionUnlink; \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK( \
+ MOZ_FOR_EACH_EXPAND_HELPER native_members_) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK(MOZ_FOR_EACH_EXPAND_HELPER js_members_) \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(class_) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE( \
+ MOZ_FOR_EACH_EXPAND_HELPER native_members_) \
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(class_) \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBERS( \
+ MOZ_FOR_EACH_EXPAND_HELPER js_members_) \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER \
+ NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+#endif /* nsWrapperCache_h___ */