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| -rw-r--r-- | dom/base/nsWrapperCache.h | 646 |
1 files changed, 646 insertions, 0 deletions
diff --git a/dom/base/nsWrapperCache.h b/dom/base/nsWrapperCache.h new file mode 100644 index 0000000000..d7232470d9 --- /dev/null +++ b/dom/base/nsWrapperCache.h @@ -0,0 +1,646 @@ +/* -*- 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___ */ |