Bug 1316277 - Move intersection observer list from DOMSlots to a property. r=mrbkap

--HG--
extra : rebase_source : fcaa7d31e0a99ad666e0091c56cd9858e3afcc4b

dom/base/Element.cpp

@@ -4194,13 +4194,6 @@ Element::ClearDataset()
   slots->mDataset = nullptr;
 }
 
-nsDataHashtable<nsRefPtrHashKey<DOMIntersectionObserver>, int32_t>*
-Element::RegisteredIntersectionObservers()
-{
-  nsExtendedDOMSlots* slots = ExtendedDOMSlots();
-  return &slots->mRegisteredIntersectionObservers;
-}
-
 enum nsPreviousIntersectionThreshold {
   eUninitialized = -2,
   eNonIntersecting = -1
@@ -4209,7 +4202,20 @@ enum nsPreviousIntersectionThreshold {
 void
 Element::RegisterIntersectionObserver(DOMIntersectionObserver* aObserver)
 {
-  RegisteredIntersectionObservers()->LookupForAdd(aObserver).OrInsert([]() {
+  IntersectionObserverList* observers =
+    static_cast<IntersectionObserverList*>(
+      GetProperty(nsGkAtoms::intersectionobserverlist)
+    );
+
+  if (!observers) {
+    observers = new IntersectionObserverList();
+    observers->Put(aObserver, eUninitialized);
+    SetProperty(nsGkAtoms::intersectionobserverlist, observers,
+                nsINode::DeleteProperty<IntersectionObserverList>);
+    return;
+  }
+
+  observers->LookupForAdd(aObserver).OrInsert([]() {
     // Value can be:
     //   -2:   Makes sure next calculated threshold always differs, leading to a
     //         notification task being scheduled.
@@ -4222,14 +4228,44 @@ Element::RegisterIntersectionObserver(DOMIntersectionObserver* aObserver)
 void
 Element::UnregisterIntersectionObserver(DOMIntersectionObserver* aObserver)
 {
-  RegisteredIntersectionObservers()->Remove(aObserver);
+  IntersectionObserverList* observers =
+    static_cast<IntersectionObserverList*>(
+      GetProperty(nsGkAtoms::intersectionobserverlist)
+    );
+  if (observers) {
+    observers->Remove(aObserver);
+  }
+}
+
+void
+Element::UnlinkIntersectionObservers()
+{
+  IntersectionObserverList* observers =
+    static_cast<IntersectionObserverList*>(
+      GetProperty(nsGkAtoms::intersectionobserverlist)
+    );
+  if (!observers) {
+    return;
+  }
+  for (auto iter = observers->Iter(); !iter.Done(); iter.Next()) {
+    DOMIntersectionObserver* observer = iter.Key();
+    observer->UnlinkTarget(*this);
+  }
+  observers->Clear();
 }
 
 bool
 Element::UpdateIntersectionObservation(DOMIntersectionObserver* aObserver, int32_t aThreshold)
 {
+  IntersectionObserverList* observers =
+    static_cast<IntersectionObserverList*>(
+      GetProperty(nsGkAtoms::intersectionobserverlist)
+    );
+  if (!observers) {
+    return false;
+  }
   bool updated = false;
-  if (auto entry = RegisteredIntersectionObservers()->Lookup(aObserver)) {
+  if (auto entry = observers->Lookup(aObserver)) {
     updated = entry.Data() != aThreshold;
     entry.Data() = aThreshold;
   }

dom/base/Element.h

@@ -73,6 +73,8 @@ namespace dom {
   class ElementOrCSSPseudoElement;
   class UnrestrictedDoubleOrKeyframeAnimationOptions;
   enum class CallerType : uint32_t;
+  typedef nsDataHashtable<nsRefPtrHashKey<DOMIntersectionObserver>, int32_t>
+    IntersectionObserverList;
 } // namespace dom
 } // namespace mozilla
 
@@ -1436,6 +1438,7 @@ public:
 
   void RegisterIntersectionObserver(DOMIntersectionObserver* aObserver);
   void UnregisterIntersectionObserver(DOMIntersectionObserver* aObserver);
+  void UnlinkIntersectionObservers();
   bool UpdateIntersectionObservation(DOMIntersectionObserver* aObserver, int32_t threshold);
 
 protected:
@@ -1721,9 +1724,6 @@ protected:
   nsDOMTokenList* GetTokenList(nsIAtom* aAtom,
                                const DOMTokenListSupportedTokenArray aSupportedTokens = nullptr);
 
-  nsDataHashtable<nsRefPtrHashKey<DOMIntersectionObserver>, int32_t>*
-    RegisteredIntersectionObservers();
-
 private:
   /**
    * Hook for implementing GetClasses.  This is guaranteed to only be

dom/base/FragmentOrElement.cpp

@@ -816,14 +816,6 @@ FragmentOrElement::nsDOMSlots::Traverse(nsCycleCollectionTraversalCallback &cb)
     }
   }
 
-  for (auto iter = mExtendedSlots->mRegisteredIntersectionObservers.Iter();
-       !iter.Done(); iter.Next()) {
-    DOMIntersectionObserver* observer = iter.Key();
-    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb,
-                                       "mExtendedSlots->mRegisteredIntersectionObservers[i]");
-    cb.NoteXPCOMChild(observer);
-  }
-
   NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mFrameLoaderOrOpener");
   cb.NoteXPCOMChild(mExtendedSlots->mFrameLoaderOrOpener);
 }
@@ -856,7 +848,6 @@ FragmentOrElement::nsDOMSlots::Unlink()
     }
     mExtendedSlots->mCustomElementData = nullptr;
   }
-  mExtendedSlots->mRegisteredIntersectionObservers.Clear();
   nsCOMPtr<nsIFrameLoader> frameLoader =
     do_QueryInterface(mExtendedSlots->mFrameLoaderOrOpener);
   if (frameLoader) {
@@ -1563,6 +1554,11 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(FragmentOrElement)
   // which is dispatched in UnbindFromTree.
 
   if (tmp->HasProperties()) {
+    if (tmp->IsElement()) {
+      Element* elem = tmp->AsElement();
+      elem->UnlinkIntersectionObservers();
+    }
+
     if (tmp->IsHTMLElement() || tmp->IsSVGElement()) {
       nsIAtom*** props = Element::HTMLSVGPropertiesToTraverseAndUnlink();
       for (uint32_t i = 0; props[i]; ++i) {
@@ -1617,14 +1613,6 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(FragmentOrElement)
   {
     nsDOMSlots *slots = tmp->GetExistingDOMSlots();
     if (slots) {
-      if (slots->mExtendedSlots && tmp->IsElement()) {
-        Element* elem = tmp->AsElement();
-        for (auto iter = slots->mExtendedSlots->mRegisteredIntersectionObservers.Iter();
-             !iter.Done(); iter.Next()) {
-          DOMIntersectionObserver* observer = iter.Key();
-          observer->UnlinkTarget(*elem);
-        }
-      }
       slots->Unlink();
     }
   }
@@ -2145,6 +2133,19 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(FragmentOrElement)
 #endif
 
   if (tmp->HasProperties()) {
+    if (tmp->IsElement()) {
+      Element* elem = tmp->AsElement();
+      IntersectionObserverList* observers =
+        static_cast<IntersectionObserverList*>(
+          elem->GetProperty(nsGkAtoms::intersectionobserverlist)
+        );
+      if (observers) {
+        for (auto iter = observers->Iter(); !iter.Done(); iter.Next()) {
+          DOMIntersectionObserver* observer = iter.Key();
+          cb.NoteXPCOMChild(observer);
+        }
+      }
+    }
     if (tmp->IsHTMLElement() || tmp->IsSVGElement()) {
       nsIAtom*** props = Element::HTMLSVGPropertiesToTraverseAndUnlink();
       for (uint32_t i = 0; props[i]; ++i) {

dom/base/FragmentOrElement.h

@@ -40,7 +40,6 @@ namespace mozilla {
 class DeclarationBlock;
 namespace dom {
 struct CustomElementData;
-class DOMIntersectionObserver;
 class Element;
 } // namespace dom
 } // namespace mozilla
@@ -313,12 +312,6 @@ public:
      */
     RefPtr<CustomElementData> mCustomElementData;
 
-    /**
-     * Registered Intersection Observers on the element.
-     */
-    nsDataHashtable<nsRefPtrHashKey<DOMIntersectionObserver>, int32_t>
-      mRegisteredIntersectionObservers;
-
     /**
      * For XUL to hold either frameloader or opener.
      */

dom/base/nsGkAtomList.h

@@ -582,6 +582,7 @@ GK_ATOM(int64, "int64")
 GK_ATOM(integer, "integer")
 GK_ATOM(integrity, "integrity")
 GK_ATOM(intersection, "intersection")
+GK_ATOM(intersectionobserverlist, "intersectionobserverlist")
 GK_ATOM(is, "is")
 GK_ATOM(iscontainer, "iscontainer")
 GK_ATOM(isempty, "isempty")

dom/base/nsNodeUtils.cpp

@@ -293,19 +293,6 @@ nsNodeUtils::LastRelease(nsINode* aNode)
                                               NodeWillBeDestroyed, (aNode));
     }
 
-    if (aNode->IsElement()) {
-      Element* elem = aNode->AsElement();
-      FragmentOrElement::nsDOMSlots* domSlots =
-        static_cast<FragmentOrElement::nsDOMSlots*>(slots);
-      if (domSlots->mExtendedSlots) {
-        for (auto iter = domSlots->mExtendedSlots->mRegisteredIntersectionObservers.Iter();
-             !iter.Done(); iter.Next()) {
-          DOMIntersectionObserver* observer = iter.Key();
-          observer->UnlinkTarget(*elem);
-        }
-      }
-    }
-
     delete slots;
     aNode->mSlots = nullptr;
   }
@@ -320,6 +307,12 @@ nsNodeUtils::LastRelease(nsINode* aNode)
   }
   else {
     if (aNode->HasProperties()) {
+      if (aNode->IsElement()) {
+        Element* elem = aNode->AsElement();
+        elem->UnlinkIntersectionObservers();
+        elem->DeleteProperty(nsGkAtoms::intersectionobserverlist);
+      }
+
       // Strong reference to the document so that deleting properties can't
       // delete the document.
       nsCOMPtr<nsIDocument> document = aNode->OwnerDoc();