/* -*- 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 nsCycleCollectionParticipant_h__ #define nsCycleCollectionParticipant_h__ #include "mozilla/MacroArgs.h" #include "mozilla/MacroForEach.h" #include "nsCycleCollectionNoteChild.h" #include "js/RootingAPI.h" /** * Note: the following two IIDs only differ in one bit in the last byte. This * is a hack and is intentional in order to speed up the comparison inside * NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED. */ #define NS_XPCOMCYCLECOLLECTIONPARTICIPANT_IID \ { \ 0xc61eac14, \ 0x5f7a, \ 0x4481, \ { 0x96, 0x5e, 0x7e, 0xaa, 0x6e, 0xff, 0xa8, 0x5e } \ } /** * Special IID to get at the base nsISupports for a class. Usually this is the * canonical nsISupports pointer, but in the case of tearoffs for example it is * the base nsISupports pointer of the tearoff. This allow the cycle collector * to have separate nsCycleCollectionParticipant's for tearoffs or aggregated * classes. */ #define NS_CYCLECOLLECTIONISUPPORTS_IID \ { \ 0xc61eac14, \ 0x5f7a, \ 0x4481, \ { 0x96, 0x5e, 0x7e, 0xaa, 0x6e, 0xff, 0xa8, 0x5f } \ } /** * Just holds the IID so NS_GET_IID works. */ class nsCycleCollectionISupports { public: NS_DECLARE_STATIC_IID_ACCESSOR(NS_CYCLECOLLECTIONISUPPORTS_IID) }; NS_DEFINE_STATIC_IID_ACCESSOR(nsCycleCollectionISupports, NS_CYCLECOLLECTIONISUPPORTS_IID) namespace JS { template class Heap; } /* namespace JS */ /* * A struct defining pure virtual methods which are called when tracing cycle * collection paticipants. The appropriate method is called depending on the * type of JS GC thing. */ struct TraceCallbacks { virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JSObject** aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JS::TenuredHeap* aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const = 0; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const = 0; }; /* * An implementation of TraceCallbacks that calls a single function for all JS * GC thing types encountered. Implemented in nsCycleCollectorTraceJSHelpers.cpp. */ struct TraceCallbackFunc : public TraceCallbacks { typedef void (*Func)(JS::GCCellPtr aPtr, const char* aName, void* aClosure); explicit TraceCallbackFunc(Func aCb) : mCallback(aCb) {} virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JSObject** aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JS::TenuredHeap* aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const override; virtual void Trace(JS::Heap* aPtr, const char* aName, void* aClosure) const override; private: Func mCallback; }; /** * Participant implementation classes */ class NS_NO_VTABLE nsCycleCollectionParticipant { public: constexpr explicit nsCycleCollectionParticipant(bool aSkip, bool aTraverseShouldTrace = false) : mMightSkip(aSkip) , mTraverseShouldTrace(aTraverseShouldTrace) { } NS_IMETHOD TraverseNative(void* aPtr, nsCycleCollectionTraversalCallback& aCb) = 0; nsresult TraverseNativeAndJS(void* aPtr, nsCycleCollectionTraversalCallback& aCb) { nsresult rv = TraverseNative(aPtr, aCb); if (mTraverseShouldTrace) { // Note, we always call Trace, even if Traverse returned // NS_SUCCESS_INTERRUPTED_TRAVERSE. TraceCallbackFunc noteJsChild(&nsCycleCollectionParticipant::NoteJSChild); Trace(aPtr, noteJsChild, &aCb); } return rv; } // Implemented in nsCycleCollectorTraceJSHelpers.cpp. static void NoteJSChild(JS::GCCellPtr aGCThing, const char* aName, void* aClosure); NS_IMETHOD_(void) Root(void* aPtr) = 0; NS_IMETHOD_(void) Unlink(void* aPtr) = 0; NS_IMETHOD_(void) Unroot(void* aPtr) = 0; NS_IMETHOD_(const char*) ClassName() = 0; NS_IMETHOD_(void) Trace(void* aPtr, const TraceCallbacks& aCb, void* aClosure) {} // CanSkip is called during nsCycleCollector_forgetSkippable. If it returns // true, aPtr is removed from the purple buffer and therefore might be left // out from the cycle collector graph the next time that's constructed (unless // it's reachable in some other way). // // CanSkip is allowed to expand the set of certainly-alive objects by removing // other objects from the purple buffer, marking JS things black (in the GC // sense), and so forth. Furthermore, if aRemovingAllowed is true, this call // is allowed to remove aPtr itself from the purple buffer. // // Things can return true from CanSkip if either they know they have no // outgoing edges at all in the cycle collection graph (because then they // can't be parts of a cycle) or they know for sure they're alive. bool CanSkip(void* aPtr, bool aRemovingAllowed) { return mMightSkip ? CanSkipReal(aPtr, aRemovingAllowed) : false; } // CanSkipInCC is called during construction of the initial set of roots for // the cycle collector graph. If it returns true, aPtr is left out of that // set of roots. Note that the set of roots includes whatever is in the // purple buffer (after earlier CanSkip calls) plus various other sources of // roots, so an object can end up having CanSkipInCC called on it even if it // returned true from CanSkip. One example of this would be an object that // can potentially trace JS things. // // CanSkipInCC is allowed to remove other objects from the purple buffer but // should not remove aPtr and should not mark JS things black. It should also // not modify any reference counts. // // Things can return true from CanSkipInCC if either they know they have no // outgoing edges at all in the cycle collection graph or they know for sure // they're alive _and_ none of their outgoing edges are to gray (in the GC // sense) gcthings. See also nsWrapperCache::HasNothingToTrace and // nsWrapperCache::IsBlackAndDoesNotNeedTracing. The restriction on not // having outgoing edges to gray gcthings is because if we _do_ have them that // means we have a "strong" edge to a JS thing and since we're alive we need // to trace through it and mark keep them alive. Outgoing edges to C++ things // don't matter here, because the criteria for when a CC participant is // considered alive are slightly different for JS and C++ things: JS things // are only considered alive when reachable via an edge from a live thing, // while C++ things are also considered alive when their refcount exceeds the // number of edges via which they are reachable. bool CanSkipInCC(void* aPtr) { return mMightSkip ? CanSkipInCCReal(aPtr) : false; } // CanSkipThis is called during construction of the cycle collector graph, // when we traverse an edge to aPtr and consider adding it to the graph. If // it returns true, aPtr is not added to the graph. // // CanSkipThis is not allowed to change the liveness or reference count of any // objects. // // Things can return true from CanSkipThis if either they know they have no // outgoing edges at all in the cycle collection graph or they know for sure // they're alive. // // Note that CanSkipThis doesn't have to worry about outgoing edges to gray GC // things, because if this object could have those it already got added to the // graph during root set construction. An object should never have // CanSkipThis called on it if it has outgoing strong references to JS things. bool CanSkipThis(void* aPtr) { return mMightSkip ? CanSkipThisReal(aPtr) : false; } NS_IMETHOD_(void) DeleteCycleCollectable(void* aPtr) = 0; protected: NS_IMETHOD_(bool) CanSkipReal(void* aPtr, bool aRemovingAllowed) { NS_ASSERTION(false, "Forgot to implement CanSkipReal?"); return false; } NS_IMETHOD_(bool) CanSkipInCCReal(void* aPtr) { NS_ASSERTION(false, "Forgot to implement CanSkipInCCReal?"); return false; } NS_IMETHOD_(bool) CanSkipThisReal(void* aPtr) { NS_ASSERTION(false, "Forgot to implement CanSkipThisReal?"); return false; } private: const bool mMightSkip; const bool mTraverseShouldTrace; }; class NS_NO_VTABLE nsScriptObjectTracer : public nsCycleCollectionParticipant { public: constexpr explicit nsScriptObjectTracer(bool aSkip) : nsCycleCollectionParticipant(aSkip, true) { } NS_IMETHOD_(void) Trace(void* aPtr, const TraceCallbacks& aCb, void* aClosure) override = 0; }; class NS_NO_VTABLE nsXPCOMCycleCollectionParticipant : public nsScriptObjectTracer { public: constexpr explicit nsXPCOMCycleCollectionParticipant(bool aSkip) : nsScriptObjectTracer(aSkip) { } NS_DECLARE_STATIC_IID_ACCESSOR(NS_XPCOMCYCLECOLLECTIONPARTICIPANT_IID) NS_IMETHOD_(void) Root(void* aPtr) override; NS_IMETHOD_(void) Unroot(void* aPtr) override; NS_IMETHOD_(void) Trace(void* aPtr, const TraceCallbacks& aCb, void* aClosure) override; static bool CheckForRightISupports(nsISupports* aSupports); }; NS_DEFINE_STATIC_IID_ACCESSOR(nsXPCOMCycleCollectionParticipant, NS_XPCOMCYCLECOLLECTIONPARTICIPANT_IID) /////////////////////////////////////////////////////////////////////////////// // Helpers for implementing a QI to nsXPCOMCycleCollectionParticipant /////////////////////////////////////////////////////////////////////////////// #define NS_CYCLE_COLLECTION_CLASSNAME(_class) \ _class::NS_CYCLE_COLLECTION_INNERCLASS // The IIDs for nsXPCOMCycleCollectionParticipant and nsCycleCollectionISupports // are special in that they only differ in their last byte. This allows for the // optimization below where we first check the first three words of the IID and // if we find a match we check the last word to decide which case we have to // deal with. #define NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(_class) \ if (TopThreeWordsEquals(aIID, NS_GET_IID(nsXPCOMCycleCollectionParticipant), \ NS_GET_IID(nsCycleCollectionISupports)) && \ /* The calls to LowWordEquals here are repeated inside the if branch. \ This is due to the fact that we need to maintain the if/else chain \ for these macros, so that the control flow never enters the if branch\ unless if we're certain one of the LowWordEquals() branches will get \ executed. */ \ (LowWordEquals(aIID, NS_GET_IID(nsXPCOMCycleCollectionParticipant)) || \ LowWordEquals(aIID, NS_GET_IID(nsCycleCollectionISupports)))) { \ if (LowWordEquals(aIID, NS_GET_IID(nsXPCOMCycleCollectionParticipant))) { \ *aInstancePtr = NS_CYCLE_COLLECTION_PARTICIPANT(_class); \ return NS_OK; \ } \ if (LowWordEquals(aIID, NS_GET_IID(nsCycleCollectionISupports))) { \ *aInstancePtr = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ return NS_OK; \ } else { \ /* Avoid warnings about foundInterface being left uninitialized. */ \ foundInterface = nullptr; \ } \ } else #define NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(_class) \ NS_INTERFACE_MAP_BEGIN(_class) \ NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(_class) #define NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(_class) \ if (rv == NS_OK) return rv; \ nsISupports* foundInterface; \ NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(_class) // The IIDs for nsXPCOMCycleCollectionParticipant and nsCycleCollectionISupports // are special in that they only differ in their last byte. This allows for the // optimization below where we first check the first three words of the IID and // if we find a match we check the last word to decide which case we have to // deal with. #define NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(_class) \ NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr) \ { \ NS_PRECONDITION(aInstancePtr, "null out param"); \ \ if (TopThreeWordsEquals(aIID, NS_GET_IID(nsXPCOMCycleCollectionParticipant), \ NS_GET_IID(nsCycleCollectionISupports))) { \ if (LowWordEquals(aIID, NS_GET_IID(nsXPCOMCycleCollectionParticipant))) { \ *aInstancePtr = NS_CYCLE_COLLECTION_PARTICIPANT(_class); \ return NS_OK; \ } \ if (LowWordEquals(aIID, NS_GET_IID(nsCycleCollectionISupports))) { \ *aInstancePtr = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this); \ return NS_OK; \ } \ } \ nsresult rv = NS_ERROR_FAILURE; #define NS_CYCLE_COLLECTION_UPCAST(obj, clazz) \ NS_CYCLE_COLLECTION_CLASSNAME(clazz)::Upcast(obj) #ifdef DEBUG #define NS_CHECK_FOR_RIGHT_PARTICIPANT(_ptr) _ptr->CheckForRightParticipant() #else #define NS_CHECK_FOR_RIGHT_PARTICIPANT(_ptr) #endif // The default implementation of this class template is empty, because it // should never be used: see the partial specializations below. template::value> struct DowncastCCParticipantImpl { }; // Specialization for XPCOM CC participants template struct DowncastCCParticipantImpl { static T* Run(void* aPtr) { nsISupports* s = static_cast(aPtr); MOZ_ASSERT(NS_CYCLE_COLLECTION_CLASSNAME(T)::CheckForRightISupports(s), "not the nsISupports pointer we expect"); T* rval = NS_CYCLE_COLLECTION_CLASSNAME(T)::Downcast(s); NS_CHECK_FOR_RIGHT_PARTICIPANT(rval); return rval; } }; // Specialization for native CC participants template struct DowncastCCParticipantImpl { static T* Run(void* aPtr) { return static_cast(aPtr); } }; template T* DowncastCCParticipant(void* aPtr) { return DowncastCCParticipantImpl::Run(aPtr); } /////////////////////////////////////////////////////////////////////////////// // Helpers for implementing CanSkip methods /////////////////////////////////////////////////////////////////////////////// // See documentation for nsCycleCollectionParticipant::CanSkip for documentation // about this method. #define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(_class) \ NS_IMETHODIMP_(bool) \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::CanSkipReal(void *p, \ bool aRemovingAllowed) \ { \ _class *tmp = DowncastCCParticipant<_class >(p); #define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_END \ (void)tmp; \ return false; \ } // See documentation for nsCycleCollectionParticipant::CanSkipInCC for // documentation about this method. #define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_BEGIN(_class) \ NS_IMETHODIMP_(bool) \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::CanSkipInCCReal(void *p) \ { \ _class *tmp = DowncastCCParticipant<_class >(p); #define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_END \ (void)tmp; \ return false; \ } // See documentation for nsCycleCollectionParticipant::CanSkipThis for // documentation about this method. #define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(_class) \ NS_IMETHODIMP_(bool) \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::CanSkipThisReal(void *p) \ { \ _class *tmp = DowncastCCParticipant<_class >(p); #define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_END \ (void)tmp; \ return false; \ } /////////////////////////////////////////////////////////////////////////////// // Helpers for implementing nsCycleCollectionParticipant::Unlink // // You need to use NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED if you want // the base class Unlink version to be called before your own implementation. // You can use NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED if you want the // base class Unlink to get called after your own implementation. You should // never use them together. /////////////////////////////////////////////////////////////////////////////// #define NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \ NS_IMETHODIMP_(void) \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::Unlink(void *p) \ { \ _class *tmp = DowncastCCParticipant<_class >(p); #define NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(_class, _base_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \ nsISupports *s = static_cast(p); \ NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::Unlink(s); #define NS_IMPL_CYCLE_COLLECTION_UNLINK_HELPER(_field) \ ImplCycleCollectionUnlink(tmp->_field); #define NS_IMPL_CYCLE_COLLECTION_UNLINK(...) \ MOZ_FOR_EACH(NS_IMPL_CYCLE_COLLECTION_UNLINK_HELPER, (), (__VA_ARGS__)) #define NS_IMPL_CYCLE_COLLECTION_UNLINK_END \ (void)tmp; \ } #define NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(_base_class) \ nsISupports *s = static_cast(p); \ NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::Unlink(s); \ (void)tmp; \ } #define NS_IMPL_CYCLE_COLLECTION_UNLINK_0(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_END /////////////////////////////////////////////////////////////////////////////// // Helpers for implementing nsCycleCollectionParticipant::Traverse /////////////////////////////////////////////////////////////////////////////// #define NS_IMPL_CYCLE_COLLECTION_DESCRIBE(_class, _refcnt) \ cb.DescribeRefCountedNode(_refcnt, #_class); #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(_class) \ NS_IMETHODIMP \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::TraverseNative \ (void *p, nsCycleCollectionTraversalCallback &cb) \ { \ _class *tmp = DowncastCCParticipant<_class >(p); #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(_class) \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(_class) \ NS_IMPL_CYCLE_COLLECTION_DESCRIBE(_class, tmp->mRefCnt.get()) // Base class' CC participant should return NS_SUCCESS_INTERRUPTED_TRAVERSE // from Traverse if it wants derived classes to not traverse anything from // their CC participant. #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(_class, _base_class) \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(_class) \ nsISupports *s = static_cast(p); \ if (NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::TraverseNative(s, cb) \ == NS_SUCCESS_INTERRUPTED_TRAVERSE) { \ return NS_SUCCESS_INTERRUPTED_TRAVERSE; \ } #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_HELPER(_field) \ ImplCycleCollectionTraverse(cb, tmp->_field, #_field, 0); #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE(...) \ MOZ_FOR_EACH(NS_IMPL_CYCLE_COLLECTION_TRAVERSE_HELPER, (), (__VA_ARGS__)) #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_RAWPTR(_field) \ CycleCollectionNoteChild(cb, tmp->_field, #_field); #define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END \ (void)tmp; \ return NS_OK; \ } /////////////////////////////////////////////////////////////////////////////// // Helpers for implementing nsScriptObjectTracer::Trace /////////////////////////////////////////////////////////////////////////////// #define NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(_class) \ void \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::Trace(void *p, \ const TraceCallbacks &aCallbacks, \ void *aClosure) \ { \ _class *tmp = DowncastCCParticipant<_class >(p); #define NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(_class, _base_class) \ NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(_class) \ nsISupports *s = static_cast(p); \ NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::Trace(s, aCallbacks, aClosure); #define NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(_field) \ aCallbacks.Trace(&tmp->_field, #_field, aClosure); // NB: The (void)tmp; hack in the TRACE_END macro exists to support // implementations that don't need to do anything in their Trace method. // Without this hack, some compilers warn about the unused tmp local. #define NS_IMPL_CYCLE_COLLECTION_TRACE_END \ (void)tmp; \ } /////////////////////////////////////////////////////////////////////////////// // Helpers for implementing a concrete nsCycleCollectionParticipant /////////////////////////////////////////////////////////////////////////////// // If a class defines a participant, then QIing an instance of that class to // nsXPCOMCycleCollectionParticipant should produce that participant. #ifdef DEBUG #define NS_CHECK_FOR_RIGHT_PARTICIPANT_BASE \ virtual void CheckForRightParticipant() #define NS_CHECK_FOR_RIGHT_PARTICIPANT_DERIVED \ virtual void CheckForRightParticipant() override #define NS_CHECK_FOR_RIGHT_PARTICIPANT_BODY(_class) \ { \ nsXPCOMCycleCollectionParticipant *p; \ CallQueryInterface(this, &p); \ MOZ_ASSERT(p == &NS_CYCLE_COLLECTION_INNERNAME, \ #_class " should QI to its own CC participant"); \ } #define NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL(_class) \ NS_CHECK_FOR_RIGHT_PARTICIPANT_BASE \ NS_CHECK_FOR_RIGHT_PARTICIPANT_BODY(_class) #define NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL_INHERITED(_class) \ NS_CHECK_FOR_RIGHT_PARTICIPANT_DERIVED \ NS_CHECK_FOR_RIGHT_PARTICIPANT_BODY(_class) #else #define NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL(_class) #define NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL_INHERITED(_class) #endif #define NS_DECL_CYCLE_COLLECTION_CLASS_NAME_METHOD(_class) \ NS_IMETHOD_(const char*) ClassName() override { return #_class; }; #define NS_DECL_CYCLE_COLLECTION_CLASS_BODY_NO_UNLINK(_class, _base) \ public: \ NS_IMETHOD TraverseNative(void *p, nsCycleCollectionTraversalCallback &cb) \ override; \ NS_DECL_CYCLE_COLLECTION_CLASS_NAME_METHOD(_class) \ NS_IMETHOD_(void) DeleteCycleCollectable(void *p) override \ { \ DowncastCCParticipant<_class>(p)->DeleteCycleCollectable(); \ } \ static _class* Downcast(nsISupports* s) \ { \ return static_cast<_class*>(static_cast<_base*>(s)); \ } \ static nsISupports* Upcast(_class *p) \ { \ return NS_ISUPPORTS_CAST(_base*, p); \ } \ template \ friend nsISupports* \ ToSupports(T* p, NS_CYCLE_COLLECTION_INNERCLASS* dummy); #define NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \ NS_DECL_CYCLE_COLLECTION_CLASS_BODY_NO_UNLINK(_class, _base) \ NS_IMETHOD_(void) Unlink(void *p) override; #define NS_PARTICIPANT_AS(type, participant) \ const_cast(reinterpret_cast(participant)) #define NS_IMPL_GET_XPCOM_CYCLE_COLLECTION_PARTICIPANT(_class) \ static constexpr nsXPCOMCycleCollectionParticipant* GetParticipant() \ { \ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \ } /** * We use this macro to force that classes that inherit from a ccable class and * declare their own participant declare themselves as inherited cc classes. * To avoid possibly unnecessary vtables we only do this checking in debug * builds. */ #ifdef DEBUG #define NOT_INHERITED_CANT_OVERRIDE virtual void BaseCycleCollectable() final {} #else #define NOT_INHERITED_CANT_OVERRIDE #endif #define NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(_class, _base) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsXPCOMCycleCollectionParticipant \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : nsXPCOMCycleCollectionParticipant(aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \ 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_CLASS(_class) \ NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(_class, _class) // Cycle collector helper for ambiguous classes that can sometimes be skipped. #define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_CLASS_AMBIGUOUS(_class, _base) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsXPCOMCycleCollectionParticipant \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = true) \ /* Ignore aSkip: we always want skippability. */ \ : nsXPCOMCycleCollectionParticipant(true) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \ 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_CLASS(_class) \ NS_DECL_CYCLE_COLLECTION_SKIPPABLE_CLASS_AMBIGUOUS(_class, _class) #define NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(_class, _base) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsXPCOMCycleCollectionParticipant \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : nsXPCOMCycleCollectionParticipant(aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \ NS_IMETHOD_(void) Trace(void *p, const TraceCallbacks &cb, void *closure) 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_SCRIPT_HOLDER_CLASS_AMBIGUOUS(_class, _base) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsXPCOMCycleCollectionParticipant \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = true) \ /* Ignore aSkip: we always want skippability. */ \ : nsXPCOMCycleCollectionParticipant(true) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_BODY(_class, _base) \ NS_IMETHOD_(void) Trace(void *p, const TraceCallbacks &cb, void *closure) override; \ 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_SCRIPT_HOLDER_CLASS(_class) \ NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS_AMBIGUOUS(_class, _class) #define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS_INHERITED(_class, \ _base_class) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public NS_CYCLE_COLLECTION_CLASSNAME(_base_class) \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = true) \ /* Ignore aSkip: we always want skippability. */ \ : NS_CYCLE_COLLECTION_CLASSNAME(_base_class) (true) {} \ 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_(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_SCRIPT_HOLDER_CLASS(_class) \ NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(_class, _class) #define NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY_NO_UNLINK(_class, \ _base_class) \ public: \ NS_IMETHOD TraverseNative(void *p, nsCycleCollectionTraversalCallback &cb) \ override; \ NS_DECL_CYCLE_COLLECTION_CLASS_NAME_METHOD(_class) \ static _class* Downcast(nsISupports* s) \ { \ return static_cast<_class*>(static_cast<_base_class*>( \ NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::Downcast(s))); \ } #define NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY(_class, _base_class) \ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY_NO_UNLINK(_class, _base_class) \ NS_IMETHOD_(void) Unlink(void *p) override; #define NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(_class, _base_class) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public NS_CYCLE_COLLECTION_CLASSNAME(_base_class) \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : NS_CYCLE_COLLECTION_CLASSNAME(_base_class) (aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY(_class, _base_class) \ 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_CLASS_INHERITED_NO_UNLINK(_class, \ _base_class) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public NS_CYCLE_COLLECTION_CLASSNAME(_base_class) \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : NS_CYCLE_COLLECTION_CLASSNAME(_base_class) (aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY_NO_UNLINK(_class, _base_class) \ 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_SCRIPT_HOLDER_CLASS_INHERITED(_class, \ _base_class) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public NS_CYCLE_COLLECTION_CLASSNAME(_base_class) \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : NS_CYCLE_COLLECTION_CLASSNAME(_base_class) (aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED_BODY(_class, _base_class) \ NS_IMETHOD_(void) Trace(void *p, const TraceCallbacks &cb, void *closure) \ 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; // Cycle collector participant declarations. #define NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS_BODY(_class) \ public: \ NS_IMETHOD_(void) Root(void *n) override; \ NS_IMETHOD_(void) Unlink(void *n) override; \ NS_IMETHOD_(void) Unroot(void *n) override; \ NS_IMETHOD TraverseNative(void *n, nsCycleCollectionTraversalCallback &cb) \ override; \ NS_DECL_CYCLE_COLLECTION_CLASS_NAME_METHOD(_class) \ NS_IMETHOD_(void) DeleteCycleCollectable(void *n) override \ { \ DowncastCCParticipant<_class>(n)->DeleteCycleCollectable(); \ } \ static _class* Downcast(void* s) \ { \ return DowncastCCParticipant<_class>(s); \ } \ static void* Upcast(_class *p) \ { \ return static_cast(p); \ } #define NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(_class) \ void DeleteCycleCollectable(void) \ { \ delete this; \ } \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsCycleCollectionParticipant \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : nsCycleCollectionParticipant(aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS_BODY(_class) \ static constexpr nsCycleCollectionParticipant* GetParticipant() \ { \ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \ } \ }; \ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; #define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_NATIVE_CLASS(_class) \ void DeleteCycleCollectable(void) \ { \ delete this; \ } \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsCycleCollectionParticipant \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = true) \ /* Ignore aSkip: we always want skippability. */ \ : nsCycleCollectionParticipant(true) {} \ private: \ NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS_BODY(_class) \ NS_IMETHOD_(bool) CanSkipReal(void *p, bool aRemovingAllowed) override; \ NS_IMETHOD_(bool) CanSkipInCCReal(void *p) override; \ NS_IMETHOD_(bool) CanSkipThisReal(void *p) override; \ static nsCycleCollectionParticipant* GetParticipant() \ { \ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \ } \ }; \ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; #define NS_DECL_CYCLE_COLLECTION_SKIPPABLE_NATIVE_CLASS_WITH_CUSTOM_DELETE(_class) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsCycleCollectionParticipant \ { \ public: \ constexpr NS_CYCLE_COLLECTION_INNERCLASS () \ : nsCycleCollectionParticipant(true) {} \ private: \ NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS_BODY(_class) \ NS_IMETHOD_(bool) CanSkipReal(void *p, bool aRemovingAllowed) override; \ NS_IMETHOD_(bool) CanSkipInCCReal(void *p) override; \ NS_IMETHOD_(bool) CanSkipThisReal(void *p) override; \ static nsCycleCollectionParticipant* GetParticipant() \ { \ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \ } \ }; \ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; #define NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(_class) \ void DeleteCycleCollectable(void) \ { \ delete this; \ } \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsScriptObjectTracer \ { \ public: \ constexpr explicit NS_CYCLE_COLLECTION_INNERCLASS (bool aSkip = false) \ : nsScriptObjectTracer(aSkip) {} \ private: \ NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS_BODY(_class) \ NS_IMETHOD_(void) Trace(void *p, const TraceCallbacks &cb, void *closure) \ override; \ static constexpr nsScriptObjectTracer* GetParticipant() \ { \ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \ } \ }; \ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; #define NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(_class, _root_function) \ NS_IMETHODIMP_(void) \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::Root(void *p) \ { \ _class *tmp = static_cast<_class*>(p); \ tmp->_root_function(); \ } #define NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(_class, _unroot_function) \ NS_IMETHODIMP_(void) \ NS_CYCLE_COLLECTION_CLASSNAME(_class)::Unroot(void *p) \ { \ _class *tmp = static_cast<_class*>(p); \ tmp->_unroot_function(); \ } #define NS_IMPL_CYCLE_COLLECTION_CLASS(_class) \ _class::NS_CYCLE_COLLECTION_INNERCLASS _class::NS_CYCLE_COLLECTION_INNERNAME; // NB: This is not something you usually want to use. It is here to allow // adding things to the CC graph to help debugging via CC logs, but it does not // traverse or unlink anything, so it is useless for anything else. #define NS_IMPL_CYCLE_COLLECTION_0(_class) \ NS_IMPL_CYCLE_COLLECTION_CLASS(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(_class) \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END #define NS_IMPL_CYCLE_COLLECTION(_class, ...) \ NS_IMPL_CYCLE_COLLECTION_CLASS(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK(__VA_ARGS__) \ 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 // If you are looking for NS_IMPL_CYCLE_COLLECTION_INHERITED_0(_class, _base) // you should instead not declare any cycle collected stuff in _class, so it // will just inherit the CC declarations from _base. #define NS_IMPL_CYCLE_COLLECTION_INHERITED(_class, _base, ...) \ NS_IMPL_CYCLE_COLLECTION_CLASS(_class) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(_class, _base) \ NS_IMPL_CYCLE_COLLECTION_UNLINK(__VA_ARGS__) \ NS_IMPL_CYCLE_COLLECTION_UNLINK_END \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(_class, _base) \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(__VA_ARGS__) \ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END #define NS_CYCLE_COLLECTION_NOTE_EDGE_NAME CycleCollectionNoteEdgeName /** * Convenience macros for defining nISupports methods in a cycle collected class. */ #define NS_IMPL_QUERY_INTERFACE_CYCLE_COLLECTION_INHERITED(aClass, aSuper, ...) \ NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(aClass) \ NS_INTERFACE_TABLE_INHERITED(aClass, __VA_ARGS__) \ NS_INTERFACE_TABLE_TAIL_INHERITING(aSuper) #define NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED(aClass, aSuper, ...) \ NS_IMPL_QUERY_INTERFACE_CYCLE_COLLECTION_INHERITED(aClass, aSuper, __VA_ARGS__) \ NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \ NS_IMPL_RELEASE_INHERITED(aClass, aSuper) #define NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(aClass, aSuper) \ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(aClass) \ NS_INTERFACE_MAP_END_INHERITING(aSuper) \ NS_IMPL_ADDREF_INHERITED(aClass, aSuper) \ NS_IMPL_RELEASE_INHERITED(aClass, aSuper) /** * Equivalency of the high three words where two IIDs have the same * top three words but not the same low word. */ inline bool TopThreeWordsEquals(const nsID& aID, const nsID& aOther1, const nsID& aOther2) { MOZ_ASSERT((((uint32_t*)&aOther1.m0)[0] == ((uint32_t*)&aOther2.m0)[0]) && (((uint32_t*)&aOther1.m0)[1] == ((uint32_t*)&aOther2.m0)[1]) && (((uint32_t*)&aOther1.m0)[2] == ((uint32_t*)&aOther2.m0)[2]) && (((uint32_t*)&aOther1.m0)[3] != ((uint32_t*)&aOther2.m0)[3])); return ((((uint32_t*)&aID.m0)[0] == ((uint32_t*)&aOther1.m0)[0]) && (((uint32_t*)&aID.m0)[1] == ((uint32_t*)&aOther1.m0)[1]) && (((uint32_t*)&aID.m0)[2] == ((uint32_t*)&aOther1.m0)[2])); } /** * Equivalency of the fourth word where the two IIDs have the same * top three words but not the same low word. */ inline bool LowWordEquals(const nsID& aID, const nsID& aOther) { return (((uint32_t*)&aID.m0)[3] == ((uint32_t*)&aOther.m0)[3]); } #endif // nsCycleCollectionParticipant_h__