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/* -*- 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 */
#ifndef mozilla_dom_shadowroot_h__
#define mozilla_dom_shadowroot_h__
#include "mozilla/DOMEventTargetHelper.h"
#include "mozilla/dom/DocumentBinding.h"
#include "mozilla/dom/DocumentFragment.h"
#include "mozilla/dom/DocumentOrShadowRoot.h"
#include "mozilla/dom/NameSpaceConstants.h"
#include "mozilla/dom/ShadowRootBinding.h"
#include "mozilla/ServoBindings.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsStubMutationObserver.h"
#include "nsTHashtable.h"
class nsAtom;
class nsIContent;
namespace mozilla {
class EventChainPreVisitor;
class ServoStyleRuleMap;
enum class StyleRuleChangeKind : uint32_t;
namespace css {
class Rule;
namespace dom {
class CSSImportRule;
class Element;
class HTMLInputElement;
class ShadowRoot final : public DocumentFragment, public DocumentOrShadowRoot {
friend class DocumentOrShadowRoot;
using Declarative = Element::ShadowRootDeclarative;
using IsClonable = Element::ShadowRootClonable;
using IsSerializable = Element::ShadowRootSerializable;
NS_IMPL_FROMNODE_HELPER(ShadowRoot, IsShadowRoot());
ShadowRoot(Element* aElement, ShadowRootMode aMode,
Element::DelegatesFocus aDelegatesFocus,
SlotAssignmentMode aSlotAssignment, IsClonable aClonable,
IsSerializable aIsSerializable, Declarative aDeclarative,
already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
void AddSizeOfExcludingThis(nsWindowSizes&, size_t* aNodeSize) const final;
// Try to reassign an element or text to a slot.
void MaybeReassignContent(nsIContent& aElementOrText);
// Called when an element is inserted as a direct child of our host. Tries to
// slot the child in one of our slots.
void MaybeSlotHostChild(nsIContent&);
// Called when a direct child of our host is removed. Tries to un-slot the
// child from the currently-assigned slot, if any.
void MaybeUnslotHostChild(nsIContent&);
// Shadow DOM v1
Element* Host() const {
"ShadowRoot always has a host, how did we create "
"this ShadowRoot?");
return GetHost();
ShadowRootMode Mode() const { return mMode; }
bool DelegatesFocus() const {
return mDelegatesFocus == Element::DelegatesFocus::Yes;
SlotAssignmentMode SlotAssignment() const { return mSlotAssignment; }
bool Clonable() const { return mIsClonable == IsClonable::Yes; }
bool IsClosed() const { return mMode == ShadowRootMode::Closed; }
bool Serializable() const { return mIsSerializable == IsSerializable::Yes; }
void RemoveSheetFromStyles(StyleSheet&);
void RuleAdded(StyleSheet&, css::Rule&);
void RuleRemoved(StyleSheet&, css::Rule&);
void RuleChanged(StyleSheet&, css::Rule*, StyleRuleChangeKind);
void ImportRuleLoaded(CSSImportRule&, StyleSheet&);
void SheetCloned(StyleSheet&);
void StyleSheetApplicableStateChanged(StyleSheet&);
* Clones internal state, for example stylesheets, of aOther to 'this'.
void CloneInternalDataFrom(ShadowRoot* aOther);
void InsertSheetAt(size_t aIndex, StyleSheet&);
// Calls UnbindFromTree for each of our kids, and also flags us as no longer
// being connected.
void Unbind();
// Only intended for UA widgets / special shadow roots, or for handling
// failure cases when adopting (see BlastSubtreeToPieces).
// Forgets our shadow host and unbinds all our kids.
void Unattach();
// Calls BindToTree on each of our kids, and also maybe flags us as being
// connected.
nsresult Bind();
* Explicitly invalidates the style and layout of the flattened-tree subtree
* rooted at the element.
* You need to use this whenever the flat tree is going to be shuffled in a
* way that layout doesn't understand via the usual ContentInserted /
* ContentAppended / ContentRemoved notifications. For example, if removing an
* element will cause a change in the flat tree such that other element will
* start showing up (like fallback content), this method needs to be called on
* an ancestor of that element.
* It is important that this runs _before_ actually shuffling the flat tree
* around, so that layout knows the actual tree that it needs to invalidate.
void InvalidateStyleAndLayoutOnSubtree(Element*);
void InsertSheetIntoAuthorData(size_t aIndex, StyleSheet&,
const nsTArray<RefPtr<StyleSheet>>&);
void AppendStyleSheet(StyleSheet& aSheet) {
InsertSheetAt(SheetCount(), aSheet);
* Represents the insertion point in a slot for a given node.
struct SlotInsertionPoint {
HTMLSlotElement* mSlot = nullptr;
Maybe<uint32_t> mIndex;
SlotInsertionPoint() = default;
SlotInsertionPoint(HTMLSlotElement* aSlot, const Maybe<uint32_t>& aIndex)
: mSlot(aSlot), mIndex(aIndex) {}
* Return the assignment corresponding to the content node at this particular
* point in time.
* It's the caller's responsibility to actually call InsertAssignedNode /
* AppendAssignedNode in the slot as needed.
SlotInsertionPoint SlotInsertionPointFor(nsIContent&);
* Returns the effective slot name for a given slottable. In most cases, this
* is just the value of the slot attribute, if any, or the empty string, but
* this also deals with the <details> shadow tree specially.
void GetSlotNameFor(const nsIContent&, nsAString&) const;
* Re-assign the current main summary if it has changed.
* Must be called only if mIsDetailsShadowTree is true.
enum class SummaryChangeReason { Deletion, Insertion };
void MaybeReassignMainSummary(SummaryChangeReason);
void AddSlot(HTMLSlotElement* aSlot);
void RemoveSlot(HTMLSlotElement* aSlot);
bool HasSlots() const { return !mSlotMap.IsEmpty(); };
HTMLSlotElement* GetDefaultSlot() const {
SlotArray* list = mSlotMap.Get(u""_ns);
return list ? (*list)->ElementAt(0) : nullptr;
void PartAdded(const Element&);
void PartRemoved(const Element&);
const nsTArray<const Element*>& Parts() const { return mParts; }
const StyleAuthorStyles* GetServoStyles() const { return mServoStyles.get(); }
StyleAuthorStyles* GetServoStyles() { return mServoStyles.get(); }
mozilla::ServoStyleRuleMap& ServoStyleRuleMap();
JSObject* WrapNode(JSContext*, JS::Handle<JSObject*> aGivenProto) final;
void NodeInfoChanged(Document* aOldDoc) override;
void AddToIdTable(Element* aElement, nsAtom* aId);
void RemoveFromIdTable(Element* aElement, nsAtom* aId);
// WebIDL methods.
using mozilla::dom::DocumentOrShadowRoot::GetElementById;
Element* GetActiveElement();
* These methods allow UA Widget to insert DOM elements into the Shadow ROM
* without putting their DOM reflectors to content scope first.
* The inserted DOM will have their reflectors in the UA Widget scope.
nsINode* ImportNodeAndAppendChildAt(nsINode& aParentNode, nsINode& aNode,
bool aDeep, mozilla::ErrorResult& rv);
nsINode* CreateElementAndAppendChildAt(nsINode& aParentNode,
const nsAString& aTagName,
mozilla::ErrorResult& rv);
bool IsUAWidget() const { return HasBeenInUAWidget(); }
void SetIsUAWidget() {
bool IsAvailableToElementInternals() const {
return mIsAvailableToElementInternals;
void SetAvailableToElementInternals() {
mIsAvailableToElementInternals = true;
void GetEventTargetParent(EventChainPreVisitor& aVisitor) override;
bool IsDeclarative() const { return mIsDeclarative == Declarative::Yes; }
void SetIsDeclarative(Declarative aIsDeclarative) {
mIsDeclarative = aIsDeclarative;
void SetIsDeclarative(bool aIsDeclarative) {
mIsDeclarative = aIsDeclarative ? Declarative::Yes : Declarative::No;
void SetHTMLUnsafe(const nsAString& aHTML);
void GetHTML(const GetHTMLOptions& aOptions, nsAString& aResult);
// FIXME(emilio): This will need to become more fine-grained.
void ApplicableRulesChanged();
virtual ~ShadowRoot();
// Make sure that the first field is pointer-aligned so it doesn't get packed
// in the base class' padding, since otherwise rust-bindgen can't generate
// correct bindings for it, see
// The computed data from the style sheets.
UniquePtr<StyleAuthorStyles> mServoStyles;
UniquePtr<mozilla::ServoStyleRuleMap> mStyleRuleMap;
using SlotArray = TreeOrderedArray<HTMLSlotElement*>;
// Map from name of slot to an array of all slots in the shadow DOM with with
// the given name. The slots are stored as a weak pointer because the elements
// are in the shadow tree and should be kept alive by its parent.
nsClassHashtable<nsStringHashKey, SlotArray> mSlotMap;
// Unordered array of all elements that have a part attribute in this shadow
// tree.
nsTArray<const Element*> mParts;
const ShadowRootMode mMode;
Element::DelegatesFocus mDelegatesFocus;
const SlotAssignmentMode mSlotAssignment;
// Whether this is the <details> internal shadow tree.
bool mIsDetailsShadowTree : 1;
bool mIsAvailableToElementInternals : 1;
Declarative mIsDeclarative;
const IsClonable mIsClonable;
const IsSerializable mIsSerializable;
nsresult Clone(dom::NodeInfo*, nsINode** aResult) const override;
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_shadowroot_h__