From cc533eaee5b800a534b93484598779debcdf5591 Mon Sep 17 00:00:00 2001 From: Gaming4JC Date: Sat, 4 Jan 2020 19:48:30 -0500 Subject: Bug 1377993 - Make node slots less memory hungry in common cases. Tag UXP Issue #1344 --- dom/base/Element.cpp | 16 ++--- dom/base/Element.h | 4 +- dom/base/FragmentOrElement.cpp | 145 +++++++++++++++++++++++++---------------- dom/base/FragmentOrElement.h | 128 +++++++++++++++++++++++------------- dom/base/ShadowRoot.cpp | 4 +- dom/base/nsNodeUtils.cpp | 9 ++- 6 files changed, 188 insertions(+), 118 deletions(-) (limited to 'dom/base') diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp index 7d926f6bb..81cc41210 100644 --- a/dom/base/Element.cpp +++ b/dom/base/Element.cpp @@ -1595,7 +1595,7 @@ Element::BindToTree(nsIDocument* aDocument, nsIContent* aParent, #endif { if (aBindingParent) { - nsDOMSlots *slots = DOMSlots(); + nsExtendedDOMSlots* slots = ExtendedDOMSlots(); slots->mBindingParent = aBindingParent; // Weak, so no addref happens. } @@ -1618,7 +1618,7 @@ Element::BindToTree(nsIDocument* aDocument, nsIContent* aParent, } ShadowRoot* parentContainingShadow = aParent->GetContainingShadow(); if (parentContainingShadow) { - DOMSlots()->mContainingShadow = parentContainingShadow; + ExtendedDOMSlots()->mContainingShadow = parentContainingShadow; } } @@ -2007,7 +2007,7 @@ Element::UnbindFromTree(bool aDeep, bool aNullParent) } #endif - nsDOMSlots* slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { if (clearBindingParent) { slots->mBindingParent = nullptr; @@ -2055,7 +2055,7 @@ Element::UnbindFromTree(bool aDeep, bool aNullParent) nsICSSDeclaration* Element::GetSMILOverrideStyle() { - Element::nsDOMSlots *slots = DOMSlots(); + Element::nsExtendedDOMSlots* slots = ExtendedDOMSlots(); if (!slots->mSMILOverrideStyle) { slots->mSMILOverrideStyle = new nsDOMCSSAttributeDeclaration(this, true); @@ -2067,7 +2067,7 @@ Element::GetSMILOverrideStyle() DeclarationBlock* Element::GetSMILOverrideStyleDeclaration() { - Element::nsDOMSlots *slots = GetExistingDOMSlots(); + Element::nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); return slots ? slots->mSMILOverrideStyleDeclaration.get() : nullptr; } @@ -2075,7 +2075,7 @@ nsresult Element::SetSMILOverrideStyleDeclaration(DeclarationBlock* aDeclaration, bool aNotify) { - Element::nsDOMSlots *slots = DOMSlots(); + Element::nsExtendedDOMSlots* slots = ExtendedDOMSlots(); slots->mSMILOverrideStyleDeclaration = aDeclaration; @@ -3988,7 +3988,7 @@ Element::ClearDataset() nsDataHashtable, int32_t>* Element::RegisteredIntersectionObservers() { - nsDOMSlots* slots = DOMSlots(); + nsExtendedDOMSlots* slots = ExtendedDOMSlots(); return &slots->mRegisteredIntersectionObservers; } @@ -4041,7 +4041,7 @@ Element::UpdateIntersectionObservation(DOMIntersectionObserver* aObserver, int32 void Element::SetCustomElementData(CustomElementData* aData) { - nsDOMSlots *slots = DOMSlots(); + nsExtendedDOMSlots *slots = ExtendedDOMSlots(); MOZ_ASSERT(!slots->mCustomElementData, "Custom element data may not be changed once set."); slots->mCustomElementData = aData; } diff --git a/dom/base/Element.h b/dom/base/Element.h index 6d8bc823e..e7218ee93 100644 --- a/dom/base/Element.h +++ b/dom/base/Element.h @@ -398,7 +398,7 @@ public: */ inline CustomElementData* GetCustomElementData() const { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { return slots->mCustomElementData; } @@ -837,7 +837,7 @@ public: ShadowRoot *FastGetShadowRoot() const { - nsDOMSlots* slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); return slots ? slots->mShadowRoot.get() : nullptr; } diff --git a/dom/base/FragmentOrElement.cpp b/dom/base/FragmentOrElement.cpp index bf0679d9f..5755fb817 100644 --- a/dom/base/FragmentOrElement.cpp +++ b/dom/base/FragmentOrElement.cpp @@ -530,8 +530,7 @@ nsNodeSupportsWeakRefTearoff::GetWeakReference(nsIWeakReference** aInstancePtr) //---------------------------------------------------------------------- FragmentOrElement::nsDOMSlots::nsDOMSlots() : nsINode::nsSlots(), - mDataset(nullptr), - mBindingParent(nullptr) + mDataset(nullptr) { } @@ -543,84 +542,104 @@ FragmentOrElement::nsDOMSlots::~nsDOMSlots() } void -FragmentOrElement::nsDOMSlots::Traverse(nsCycleCollectionTraversalCallback &cb, bool aIsXUL) +FragmentOrElement::nsDOMSlots::Traverse(nsCycleCollectionTraversalCallback &cb) { NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mStyle"); cb.NoteXPCOMChild(mStyle.get()); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mSMILOverrideStyle"); - cb.NoteXPCOMChild(mSMILOverrideStyle.get()); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mAttributeMap"); cb.NoteXPCOMChild(mAttributeMap.get()); - if (aIsXUL) { - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mControllers"); - cb.NoteXPCOMChild(mControllers); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mChildrenList"); + cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIDOMNodeList*, mChildrenList)); + + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mClassList"); + cb.NoteXPCOMChild(mClassList.get()); + + if (!mExtendedSlots) { + return; } - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mXBLBinding"); - cb.NoteNativeChild(mXBLBinding, NS_CYCLE_COLLECTION_PARTICIPANT(nsXBLBinding)); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mSMILOverrideStyle"); + cb.NoteXPCOMChild(mExtendedSlots->mSMILOverrideStyle.get()); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mXBLInsertionParent"); - cb.NoteXPCOMChild(mXBLInsertionParent.get()); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mControllers"); + cb.NoteXPCOMChild(mExtendedSlots->mControllers); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mShadowRoot"); - cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIContent*, mShadowRoot)); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mLabelsList"); + cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIDOMNodeList*,mExtendedSlots-> mLabelsList)); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mContainingShadow"); - cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIContent*, mContainingShadow)); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mShadowRoot"); + cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIContent*, mExtendedSlots->mShadowRoot)); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mChildrenList"); - cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIDOMNodeList*, mChildrenList)); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mContainingShadow"); + cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIContent*, mExtendedSlots->mContainingShadow)); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mLabelsList"); - cb.NoteXPCOMChild(NS_ISUPPORTS_CAST(nsIDOMNodeList*, mLabelsList)); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mXBLBinding"); + cb.NoteNativeChild(mExtendedSlots->mXBLBinding, + NS_CYCLE_COLLECTION_PARTICIPANT(nsXBLBinding)); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mClassList"); - cb.NoteXPCOMChild(mClassList.get()); + NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mExtendedSlots->mXBLInsertionParent"); + cb.NoteXPCOMChild(mExtendedSlots->mXBLInsertionParent.get()); - if (mCustomElementData) { - for (uint32_t i = 0; i < mCustomElementData->mCallbackQueue.Length(); i++) { - mCustomElementData->mCallbackQueue[i]->Traverse(cb); + if (mExtendedSlots->mCustomElementData) { + for (uint32_t i = 0; + i < mExtendedSlots->mCustomElementData->mCallbackQueue.Length(); i++) { + mExtendedSlots->mCustomElementData->mCallbackQueue[i]->Traverse(cb); } } - for (auto iter = mRegisteredIntersectionObservers.Iter(); !iter.Done(); iter.Next()) { + for (auto iter = mExtendedSlots->mRegisteredIntersectionObservers.Iter(); + !iter.Done(); iter.Next()) { DOMIntersectionObserver* observer = iter.Key(); - NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mSlots->mRegisteredIntersectionObservers[i]"); + 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); } void -FragmentOrElement::nsDOMSlots::Unlink(bool aIsXUL) +FragmentOrElement::nsDOMSlots::Unlink() { mStyle = nullptr; - mSMILOverrideStyle = nullptr; if (mAttributeMap) { mAttributeMap->DropReference(); mAttributeMap = nullptr; } - if (aIsXUL) - NS_IF_RELEASE(mControllers); - - MOZ_ASSERT(!mXBLBinding); - - mXBLInsertionParent = nullptr; - mShadowRoot = nullptr; - mContainingShadow = nullptr; mChildrenList = nullptr; - mLabelsList = nullptr; - mCustomElementData = nullptr; mClassList = nullptr; - mRegisteredIntersectionObservers.Clear(); + + if (!mExtendedSlots) { + return; + } + + mExtendedSlots->mSMILOverrideStyle = nullptr; + mExtendedSlots->mControllers = nullptr; + mExtendedSlots->mLabelsList = nullptr; + mExtendedSlots->mShadowRoot = nullptr; + mExtendedSlots->mContainingShadow = nullptr; + MOZ_ASSERT(!(mExtendedSlots->mXBLBinding)); + mExtendedSlots->mXBLInsertionParent = nullptr; + mExtendedSlots->mCustomElementData = nullptr; + mExtendedSlots->mRegisteredIntersectionObservers.Clear(); + nsCOMPtr frameLoader = + do_QueryInterface(mExtendedSlots->mFrameLoaderOrOpener); + if (frameLoader) { + static_cast(frameLoader.get())->Destroy(); + } + mExtendedSlots->mFrameLoaderOrOpener = nullptr; } size_t FragmentOrElement::nsDOMSlots::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const { size_t n = aMallocSizeOf(this); + if (mExtendedSlots) { + n += aMallocSizeOf(mExtendedSlots.get()); + } if (mAttributeMap) { n += mAttributeMap->SizeOfIncludingThis(aMallocSizeOf); @@ -641,6 +660,19 @@ FragmentOrElement::nsDOMSlots::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) c return n; } +FragmentOrElement::nsExtendedDOMSlots::nsExtendedDOMSlots() + : mBindingParent(nullptr) +{ +} + +FragmentOrElement::nsExtendedDOMSlots::~nsExtendedDOMSlots() +{ + nsCOMPtr frameLoader = do_QueryInterface(mFrameLoaderOrOpener); + if (frameLoader) { + static_cast(frameLoader.get())->Destroy(); + } +} + FragmentOrElement::FragmentOrElement(already_AddRefed& aNodeInfo) : nsIContent(aNodeInfo) { @@ -962,7 +994,7 @@ FragmentOrElement::IsLink(nsIURI** aURI) const nsIContent* FragmentOrElement::GetBindingParent() const { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { return slots->mBindingParent; @@ -974,7 +1006,7 @@ nsXBLBinding* FragmentOrElement::GetXBLBinding() const { if (HasFlag(NODE_MAY_BE_IN_BINDING_MNGR)) { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { return slots->mXBLBinding; } @@ -1009,11 +1041,11 @@ FragmentOrElement::SetXBLBinding(nsXBLBinding* aBinding, if (aBinding) { SetFlags(NODE_MAY_BE_IN_BINDING_MNGR); - nsDOMSlots *slots = DOMSlots(); + nsExtendedDOMSlots* slots = ExtendedDOMSlots(); slots->mXBLBinding = aBinding; bindingManager->AddBoundContent(this); } else { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { slots->mXBLBinding = nullptr; } @@ -1028,7 +1060,7 @@ nsIContent* FragmentOrElement::GetXBLInsertionParent() const { if (HasFlag(NODE_MAY_BE_IN_BINDING_MNGR)) { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { return slots->mXBLInsertionParent; } @@ -1040,7 +1072,7 @@ FragmentOrElement::GetXBLInsertionParent() const ShadowRoot* FragmentOrElement::GetContainingShadow() const { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { return slots->mContainingShadow; } @@ -1050,21 +1082,21 @@ FragmentOrElement::GetContainingShadow() const void FragmentOrElement::SetShadowRoot(ShadowRoot* aShadowRoot) { - nsDOMSlots *slots = DOMSlots(); + nsExtendedDOMSlots* slots = ExtendedDOMSlots(); slots->mShadowRoot = aShadowRoot; } nsTArray& FragmentOrElement::DestInsertionPoints() { - nsDOMSlots *slots = DOMSlots(); + nsExtendedDOMSlots* slots = ExtendedDOMSlots(); return slots->mDestInsertionPoints; } nsTArray* FragmentOrElement::GetExistingDestInsertionPoints() const { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { return &slots->mDestInsertionPoints; } @@ -1075,11 +1107,11 @@ void FragmentOrElement::SetXBLInsertionParent(nsIContent* aContent) { if (aContent) { - nsDOMSlots *slots = DOMSlots(); + nsExtendedDOMSlots* slots = ExtendedDOMSlots(); SetFlags(NODE_MAY_BE_IN_BINDING_MNGR); slots->mXBLInsertionParent = aContent; } else { - nsDOMSlots *slots = GetExistingDOMSlots(); + nsExtendedDOMSlots* slots = GetExistingExtendedDOMSlots(); if (slots) { slots->mXBLInsertionParent = nullptr; } @@ -1348,14 +1380,15 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(FragmentOrElement) { nsDOMSlots *slots = tmp->GetExistingDOMSlots(); if (slots) { - if (tmp->IsElement()) { + if (slots->mExtendedSlots && tmp->IsElement()) { Element* elem = tmp->AsElement(); - for (auto iter = slots->mRegisteredIntersectionObservers.Iter(); !iter.Done(); iter.Next()) { + for (auto iter = slots->mExtendedSlots->mRegisteredIntersectionObservers.Iter(); + !iter.Done(); iter.Next()) { DOMIntersectionObserver* observer = iter.Key(); observer->UnlinkTarget(*elem); } } - slots->Unlink(tmp->IsXULElement()); + slots->Unlink(); } } @@ -1920,7 +1953,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INTERNAL(FragmentOrElement) { nsDOMSlots *slots = tmp->GetExistingDOMSlots(); if (slots) { - slots->Traverse(cb, tmp->IsXULElement()); + slots->Traverse(cb); } } NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END diff --git a/dom/base/FragmentOrElement.h b/dom/base/FragmentOrElement.h index a3a59ee43..4edd88908 100644 --- a/dom/base/FragmentOrElement.h +++ b/dom/base/FragmentOrElement.h @@ -15,6 +15,7 @@ #include "mozilla/Attributes.h" #include "mozilla/MemoryReporting.h" +#include "mozilla/UniquePtr.h" #include "nsAttrAndChildArray.h" // member #include "nsCycleCollectionParticipant.h" // NS_DECL_CYCLE_* #include "nsIContent.h" // base class @@ -239,8 +240,6 @@ protected: nsresult CopyInnerTo(FragmentOrElement* aDest); public: - // Because of a bug in MS C++ compiler nsDOMSlots must be declared public, - // otherwise nsXULElement::nsXULSlots doesn't compile. /** * There are a set of DOM- and scripting-specific instance variables * that may only be instantiated when a content object is accessed @@ -249,29 +248,13 @@ public: * in a side structure that's only allocated when the content is * accessed through the DOM. */ - class nsDOMSlots : public nsINode::nsSlots + + class nsExtendedDOMSlots { public: - nsDOMSlots(); - virtual ~nsDOMSlots(); - - void Traverse(nsCycleCollectionTraversalCallback &cb, bool aIsXUL); - void Unlink(bool aIsXUL); - - size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const; - - /** - * The .style attribute (an interface that forwards to the actual - * style rules) - * @see nsGenericHTMLElement::GetStyle - */ - nsCOMPtr mStyle; + nsExtendedDOMSlots(); - /** - * The .dataset attribute. - * @see nsGenericHTMLElement::GetDataset - */ - nsDOMStringMap* mDataset; // [Weak] + ~nsExtendedDOMSlots(); /** * SMIL Overridde style rules (for SMIL animation of CSS properties) @@ -285,35 +268,17 @@ public: RefPtr mSMILOverrideStyleDeclaration; /** - * An object implementing nsIDOMMozNamedAttrMap for this content (attributes) - * @see FragmentOrElement::GetAttributes - */ - RefPtr mAttributeMap; - - union { - /** - * The nearest enclosing content node with a binding that created us. - * @see FragmentOrElement::GetBindingParent - */ - nsIContent* mBindingParent; // [Weak] - - /** - * The controllers of the XUL Element. - */ - nsIControllers* mControllers; // [OWNER] - }; + * The nearest enclosing content node with a binding that created us. + * @see FragmentOrElement::GetBindingParent + */ + nsIContent* mBindingParent; // [Weak] /** - * An object implementing the .children property for this element. - */ - RefPtr mChildrenList; + * The controllers of the XUL Element. + */ + nsCOMPtr mControllers; /** - * An object implementing the .classList property for this element. - */ - RefPtr mClassList; - - /* * An object implementing the .labels property for this element. */ RefPtr mLabelsList; @@ -354,6 +319,55 @@ public: */ nsDataHashtable, int32_t> mRegisteredIntersectionObservers; + + /** + * For XUL to hold either frameloader or opener. + */ + nsCOMPtr mFrameLoaderOrOpener; + + }; + + class nsDOMSlots : public nsINode::nsSlots + { + public: + nsDOMSlots(); + virtual ~nsDOMSlots(); + + void Traverse(nsCycleCollectionTraversalCallback &cb); + void Unlink(); + + size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const; + + /** + * The .style attribute (an interface that forwards to the actual + * style rules) + * @see nsGenericHTMLElement::GetStyle + */ + nsCOMPtr mStyle; + + /** + * The .dataset attribute. + * @see nsGenericHTMLElement::GetDataset + */ + nsDOMStringMap* mDataset; // [Weak] + + /** + * An object implementing nsIDOMMozNamedAttrMap for this content (attributes) + * @see FragmentOrElement::GetAttributes + */ + RefPtr mAttributeMap; + + /** + * An object implementing the .children property for this element. + */ + RefPtr mChildrenList; + + /** + * An object implementing the .classList property for this element. + */ + RefPtr mClassList; + + mozilla::UniquePtr mExtendedSlots; }; protected: @@ -373,6 +387,26 @@ protected: return static_cast(GetExistingSlots()); } + nsExtendedDOMSlots* ExtendedDOMSlots() + { + nsDOMSlots* slots = DOMSlots(); + if (!slots->mExtendedSlots) { + slots->mExtendedSlots = MakeUnique(); + } + + return slots->mExtendedSlots.get(); + } + + nsExtendedDOMSlots* GetExistingExtendedDOMSlots() const + { + nsDOMSlots* slots = GetExistingDOMSlots(); + if (slots) { + return slots->mExtendedSlots.get(); + } + + return nullptr; + } + /** * Calls SetIsElementInStyleScopeFlagOnSubtree for each shadow tree attached * to this node, which is assumed to be an Element. diff --git a/dom/base/ShadowRoot.cpp b/dom/base/ShadowRoot.cpp index 9540754f7..831987a96 100644 --- a/dom/base/ShadowRoot.cpp +++ b/dom/base/ShadowRoot.cpp @@ -75,8 +75,8 @@ ShadowRoot::ShadowRoot(nsIContent* aContent, SetFlags(NODE_IS_IN_SHADOW_TREE); - DOMSlots()->mBindingParent = aContent; - DOMSlots()->mContainingShadow = this; + ExtendedDOMSlots()->mBindingParent = aContent; + ExtendedDOMSlots()->mContainingShadow = this; // Add the ShadowRoot as a mutation observer on the host to watch // for mutations because the insertion points in this ShadowRoot diff --git a/dom/base/nsNodeUtils.cpp b/dom/base/nsNodeUtils.cpp index 75d408151..c38f08a3d 100644 --- a/dom/base/nsNodeUtils.cpp +++ b/dom/base/nsNodeUtils.cpp @@ -301,9 +301,12 @@ nsNodeUtils::LastRelease(nsINode* aNode) Element* elem = aNode->AsElement(); FragmentOrElement::nsDOMSlots* domSlots = static_cast(slots); - for (auto iter = domSlots->mRegisteredIntersectionObservers.Iter(); !iter.Done(); iter.Next()) { - DOMIntersectionObserver* observer = iter.Key(); - observer->UnlinkTarget(*elem); + if (domSlots->mExtendedSlots) { + for (auto iter = domSlots->mExtendedSlots->mRegisteredIntersectionObservers.Iter(); + !iter.Done(); iter.Next()) { + DOMIntersectionObserver* observer = iter.Key(); + observer->UnlinkTarget(*elem); + } } } -- cgit v1.2.3