Add m-esr52 at 52.6.0

1 files changed, 852 insertions, 0 deletions

diff --git a/xpcom/glue/nsCycleCollectionParticipant.h b/xpcom/glue/nsCycleCollectionParticipant.h
new file mode 100644
index 0000000000..2dfbb6750e
--- /dev/null
+++ b/xpcom/glue/nsCycleCollectionParticipant.h
@@ -0,0 +1,852 @@
+/* -*- 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"
+
+#define NS_XPCOMCYCLECOLLECTIONPARTICIPANT_IID                                 \
+{                                                                              \
+    0x9674489b,                                                                \
+    0x1f6f,                                                                    \
+    0x4550,                                                                    \
+    { 0xa7, 0x30, 0xcc, 0xae, 0xdd, 0x10, 0x4c, 0xf9 }                         \
+}
+
+/**
+ * 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 T> 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<JS::Value>* aPtr, const char* aName,
+                     void* aClosure) const = 0;
+  virtual void Trace(JS::Heap<jsid>* aPtr, const char* aName,
+                     void* aClosure) const = 0;
+  virtual void Trace(JS::Heap<JSObject*>* 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<JSObject*>* aPtr, const char* aName,
+                     void* aClosure) const = 0;
+  virtual void Trace(JS::Heap<JSString*>* aPtr, const char* aName,
+                     void* aClosure) const = 0;
+  virtual void Trace(JS::Heap<JSScript*>* aPtr, const char* aName,
+                     void* aClosure) const = 0;
+  virtual void Trace(JS::Heap<JSFunction*>* 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<JS::Value>* aPtr, const char* aName,
+                     void* aClosure) const override;
+  virtual void Trace(JS::Heap<jsid>* aPtr, const char* aName,
+                     void* aClosure) const override;
+  virtual void Trace(JS::Heap<JSObject*>* 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<JSObject*>* aPtr, const char* aName,
+                     void* aClosure) const override;
+  virtual void Trace(JS::Heap<JSString*>* aPtr, const char* aName,
+                     void* aClosure) const override;
+  virtual void Trace(JS::Heap<JSScript*>* aPtr, const char* aName,
+                     void* aClosure) const override;
+  virtual void Trace(JS::Heap<JSFunction*>* aPtr, const char* aName,
+                     void* aClosure) const override;
+
+private:
+  Func mCallback;
+};
+
+/**
+ * Participant implementation classes
+ */
+class NS_NO_VTABLE nsCycleCollectionParticipant
+{
+public:
+  constexpr nsCycleCollectionParticipant() : mMightSkip(false) {}
+  constexpr explicit nsCycleCollectionParticipant(bool aSkip) : mMightSkip(aSkip) {}
+
+  NS_IMETHOD Traverse(void* aPtr, nsCycleCollectionTraversalCallback& aCb) = 0;
+
+  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) {}
+
+  // If CanSkip returns true, p is removed from the purple buffer during
+  // a call to nsCycleCollector_forgetSkippable().
+  // Note, calling CanSkip may remove objects from the purple buffer!
+  // If aRemovingAllowed is true, p can be removed from the purple buffer.
+  bool CanSkip(void* aPtr, bool aRemovingAllowed)
+  {
+    return mMightSkip ? CanSkipReal(aPtr, aRemovingAllowed) : false;
+  }
+
+  // If CanSkipInCC returns true, p is skipped when selecting roots for the
+  // cycle collector graph.
+  // Note, calling CanSkipInCC may remove other objects from the purple buffer!
+  bool CanSkipInCC(void* aPtr)
+  {
+    return mMightSkip ? CanSkipInCCReal(aPtr) : false;
+  }
+
+  // If CanSkipThis returns true, p is not added to the graph.
+  // This method is called during cycle collection, so don't
+  // change the state of any objects!
+  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;
+};
+
+class NS_NO_VTABLE nsScriptObjectTracer : public nsCycleCollectionParticipant
+{
+public:
+  constexpr nsScriptObjectTracer()
+    : nsCycleCollectionParticipant(false)
+  {
+  }
+  constexpr explicit nsScriptObjectTracer(bool aSkip)
+    : nsCycleCollectionParticipant(aSkip)
+  {
+  }
+
+  NS_IMETHOD_(void) Trace(void* aPtr, const TraceCallbacks& aCb,
+                          void* aClosure) override = 0;
+
+  // Implemented in nsCycleCollectorTraceJSHelpers.cpp.
+  static void NoteJSChild(JS::GCCellPtr aGCThing, const char* aName,
+                          void* aClosure);
+};
+
+class NS_NO_VTABLE nsXPCOMCycleCollectionParticipant : public nsScriptObjectTracer
+{
+public:
+  constexpr nsXPCOMCycleCollectionParticipant()
+    : nsScriptObjectTracer(false)
+  {
+  }
+  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
+
+#define NS_IMPL_QUERY_CYCLE_COLLECTION(_class)                                 \
+  if ( aIID.Equals(NS_GET_IID(nsXPCOMCycleCollectionParticipant)) ) {          \
+    *aInstancePtr = NS_CYCLE_COLLECTION_PARTICIPANT(_class);                   \
+    return NS_OK;                                                              \
+  } else
+
+#define NS_IMPL_QUERY_CYCLE_COLLECTION_ISUPPORTS(_class)                       \
+  if ( aIID.Equals(NS_GET_IID(nsCycleCollectionISupports)) ) {                 \
+    *aInstancePtr = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Upcast(this);       \
+    return NS_OK;                                                              \
+  } else
+
+#define NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION(_class)                        \
+  NS_IMPL_QUERY_CYCLE_COLLECTION(_class)
+
+#define NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_ISUPPORTS(_class)              \
+  NS_IMPL_QUERY_CYCLE_COLLECTION_ISUPPORTS(_class)
+
+#define NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(_class)                      \
+  NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION(_class)                              \
+  NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_ISUPPORTS(_class)
+
+#define NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(_class)                        \
+  NS_INTERFACE_MAP_BEGIN(_class)                                               \
+    NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION(_class)
+
+#define NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(_class)              \
+  NS_INTERFACE_MAP_BEGIN(_class)                                               \
+    NS_INTERFACE_MAP_ENTRY_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)
+
+#define NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(_class)            \
+  NS_IMETHODIMP _class::QueryInterface(REFNSIID aIID, void** aInstancePtr)    \
+  {                                                                           \
+    NS_PRECONDITION(aInstancePtr, "null out param");                          \
+                                                                              \
+    if ( aIID.Equals(NS_GET_IID(nsXPCOMCycleCollectionParticipant)) ) {       \
+      *aInstancePtr = NS_CYCLE_COLLECTION_PARTICIPANT(_class);                \
+      return NS_OK;                                                           \
+    }                                                                         \
+    nsresult rv;
+
+#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<typename T,
+         bool IsXPCOM = mozilla::IsBaseOf<nsISupports, T>::value>
+struct DowncastCCParticipantImpl
+{
+};
+
+// Specialization for XPCOM CC participants
+template<typename T>
+struct DowncastCCParticipantImpl<T, true>
+{
+  static T* Run(void* aPtr)
+  {
+    nsISupports* s = static_cast<nsISupports*>(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<typename T>
+struct DowncastCCParticipantImpl<T, false>
+{
+  static T* Run(void* aPtr) { return static_cast<T*>(aPtr); }
+};
+
+template<typename T>
+T*
+DowncastCCParticipant(void* aPtr)
+{
+  return DowncastCCParticipantImpl<T>::Run(aPtr);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Helpers for implementing CanSkip methods
+///////////////////////////////////////////////////////////////////////////////
+
+#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;                                                              \
+  }
+
+#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;                                                              \
+  }
+
+#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<nsISupports*>(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_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__);                              \
+  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<nsISupports*>(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)::Traverse                              \
+                         (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<nsISupports*>(p);                             \
+    if (NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::Traverse(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_STATIC_ASSERT_VALID_ARG_COUNT(__VA_ARGS__);                              \
+  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_SCRIPT_OBJECTS                       \
+  {                                                                            \
+  TraceCallbackFunc noteJsChild(&nsScriptObjectTracer::NoteJSChild);           \
+  Trace(p, noteJsChild, &cb);                                                  \
+  }
+
+#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<nsISupports*>(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 Traverse(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<typename T>                                                         \
+  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<type*>(reinterpret_cast<const type*>(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                                    \
+{                                                                              \
+  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 NS_CYCLE_COLLECTION_INNERCLASS ()                                    \
+  : 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                                            \
+{                                                                                      \
+  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 NS_CYCLE_COLLECTION_INNERCLASS ()                                             \
+  : 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)                                   \
+{                                                                                      \
+  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 Traverse(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:                                                                        \
+  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:                                                                        \
+  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)                                   \
+{                                                                                      \
+  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 Traverse(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<void*>(p);                                            \
+    }
+
+#define NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(_class)                          \
+  void DeleteCycleCollectable(void)                                            \
+  {                                                                            \
+    delete this;                                                               \
+  }                                                                            \
+  class NS_CYCLE_COLLECTION_INNERCLASS                                         \
+   : public nsCycleCollectionParticipant                                       \
+  {                                                                            \
+    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 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_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                                               \
+  {                                                                            \
+    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
+
+#endif // nsCycleCollectionParticipant_h__