tor-browser

nsINode.h (107682B)

---

/* -*- 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 nsINode_h___
#define nsINode_h___

#include <iosfwd>

#include "js/TypeDecls.h"  // for Handle, Value, JSObject, JSContext
#include "mozilla/DoublyLinkedList.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/Likely.h"
#include "mozilla/LinkedList.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "mozilla/dom/DOMString.h"
#include "mozilla/dom/EventTarget.h"  // for base class
#include "mozilla/dom/NodeBinding.h"
#include "mozilla/dom/NodeInfo.h"  // member (in nsCOMPtr)
#include "nsCOMPtr.h"              // for member, local
#include "nsGkAtoms.h"             // for nsGkAtoms::baseURIProperty
#include "nsIMutationObserver.h"
#include "nsIWeakReference.h"
#include "nsNodeInfoManager.h"  // for use in NodePrincipal()
#include "nsPropertyTable.h"    // for typedefs
#include "nsTHashtable.h"

// Including 'windows.h' will #define GetClassInfo to something else.
#ifdef XP_WIN
#  ifdef GetClassInfo
#    undef GetClassInfo
#  endif
#endif

class AttrArray;
class nsAttrChildContentList;
template <typename T>
class nsCOMArray;
class nsDOMAttributeMap;
class nsFrameSelection;
class nsGenericHTMLElement;
class nsIAnimationObserver;
class nsIContent;
class nsIContentSecurityPolicy;
class nsIFrame;
class nsIFormControl;
class nsIHTMLCollection;
class nsMultiMutationObserver;
class nsINode;
class nsINodeList;
class nsIPolicyContainer;
class nsIPrincipal;
class nsIURI;
class nsNodeSupportsWeakRefTearoff;
class nsDOMMutationObserver;
class nsRange;
class nsWindowSizes;

namespace mozilla {
class EventListenerManager;
struct StyleSelectorList;
template <typename T>
class Maybe;
class PresShell;
class TextEditor;
class WidgetEvent;
namespace dom {
/**
* @return true if aChar is what the WHATWG defines as a 'ascii whitespace'.
* https://infra.spec.whatwg.org/#ascii-whitespace
*/
inline bool IsSpaceCharacter(char16_t aChar) {
 return aChar == ' ' || aChar == '\t' || aChar == '\n' || aChar == '\r' ||
        aChar == '\f';
}
inline bool IsSpaceCharacter(char aChar) {
 return aChar == ' ' || aChar == '\t' || aChar == '\n' || aChar == '\r' ||
        aChar == '\f';
}
class AbstractRange;
class AccessibleNode;
template <typename T>
class AncestorsOfTypeIterator;
struct BoxQuadOptions;
struct ConvertCoordinateOptions;
class DocGroup;
class Document;
class DocumentFragment;
class DocumentOrShadowRoot;
class DOMPoint;
class DOMQuad;
class DOMRectReadOnly;
class Element;
class EventHandlerNonNull;
template <typename T>
class FlatTreeAncestorsOfTypeIterator;
class HTMLDialogElement;
template <typename T>
class InclusiveAncestorsOfTypeIterator;
template <typename T>
class InclusiveFlatTreeAncestorsOfTypeIterator;
class LinkStyle;
class MutationObservers;
template <typename T>
class Optional;
class OwningNodeOrString;
class SelectionNodeCache;
template <typename>
class Sequence;
class ShadowRoot;
class SVGUseElement;
class Text;
class TextOrElementOrDocument;
struct DOMPointInit;
struct GetRootNodeOptions;
enum class AllowRangeCrossShadowBoundary : bool;  // defined in AbstractRange.h
enum class CallerType : uint32_t;
}  // namespace dom
}  // namespace mozilla

#define NODE_FLAG_BIT(n_) \
 (nsWrapperCache::FlagsType(1U) << (WRAPPER_CACHE_FLAGS_BITS_USED + (n_)))

enum : uint32_t {
 // This bit will be set if the node has a listener manager.
 NODE_HAS_LISTENERMANAGER = NODE_FLAG_BIT(0),

 // Whether this node has had any properties set on it
 NODE_HAS_PROPERTIES = NODE_FLAG_BIT(1),

 // Whether the node has some ancestor, possibly itself, that is native
 // anonymous.  This includes ancestors crossing XBL scopes, in cases when an
 // XBL binding is attached to an element which has a native anonymous
 // ancestor.  This flag is set-once: once a node has it, it must not be
 // removed.
 // NOTE: Should only be used on nsIContent nodes
 NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE = NODE_FLAG_BIT(2),

 // Whether this node is the root of a native anonymous (from the perspective
 // of its parent) subtree.  This flag is set-once: once a node has it, it
 // must not be removed.
 // NOTE: Should only be used on nsIContent nodes
 NODE_IS_NATIVE_ANONYMOUS_ROOT = NODE_FLAG_BIT(3),

 NODE_IS_EDITABLE = NODE_FLAG_BIT(4),

 // Whether the node participates in a shadow tree.
 NODE_IS_IN_SHADOW_TREE = NODE_FLAG_BIT(5),

 // This node needs to go through frame construction to get a frame (or
 // undisplayed entry).
 NODE_NEEDS_FRAME = NODE_FLAG_BIT(6),

 // At least one descendant in the flattened tree has NODE_NEEDS_FRAME set.
 // This should be set on every node on the flattened tree path between the
 // node(s) with NODE_NEEDS_FRAME and the root content.
 NODE_DESCENDANTS_NEED_FRAMES = NODE_FLAG_BIT(7),

 // Set if the node has the accesskey attribute set.
 NODE_HAS_ACCESSKEY = NODE_FLAG_BIT(8),

 NODE_HAS_BEEN_IN_UA_WIDGET = NODE_FLAG_BIT(9),

 // Set if the node has a nonce value and a header delivered CSP.
 NODE_HAS_NONCE_AND_HEADER_CSP = NODE_FLAG_BIT(10),

 NODE_KEEPS_DOMARENA = NODE_FLAG_BIT(11),

 NODE_MAY_HAVE_ELEMENT_CHILDREN = NODE_FLAG_BIT(12),

 NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT = NODE_FLAG_BIT(13),

 // Remaining bits are node type specific.
 NODE_TYPE_SPECIFIC_BITS_OFFSET = 14
};

// Flags for selectors that persist to the DOM node.
enum class NodeSelectorFlags : uint32_t {
 // Node has an :empty or :-moz-only-whitespace selector
 HasEmptySelector = 1 << 0,

 /// A child of the node has a selector such that any insertion,
 /// removal, or appending of children requires restyling the parent, if the
 /// parent is an element. If the parent is the shadow root, the child's
 /// siblings are restyled.
 HasSlowSelector = 1 << 1,

 /// A child of the node has a :first-child, :-moz-first-node,
 /// :only-child, :last-child or :-moz-last-node selector.
 HasEdgeChildSelector = 1 << 2,

 /// A child of the node has a selector such that any insertion or
 /// removal of children requires restyling later siblings of that
 /// element.  Additionally (in this manner it is stronger than
 /// NODE_HAS_SLOW_SELECTOR), if a child's style changes due to any
 /// other content tree changes (e.g., the child changes to or from
 /// matching :empty due to a grandchild insertion or removal), the
 /// child's later siblings must also be restyled.
 HasSlowSelectorLaterSiblings = 1 << 3,

 /// HasSlowSelector* was set by the presence of :nth (But not of).
 HasSlowSelectorNth = 1 << 4,

 /// A child of this node might be matched by :nth-child(.. of <selector>) or
 /// :nth-last-child(.. of <selector>). If a DOM mutation may have caused the
 /// selector to either match or no longer match that child, the child's
 /// siblings are restyled.
 HasSlowSelectorNthOf = 1 << 5,

 /// All instances of :nth flags.
 HasSlowSelectorNthAll = HasSlowSelectorNthOf | HasSlowSelectorNth,

 /// Set of selector flags that may trigger a restyle on DOM append, with
 /// restyle on siblings or a single parent (And perhaps their subtrees).
 AllSimpleRestyleFlagsForAppend = HasEmptySelector | HasSlowSelector |
                                  HasEdgeChildSelector | HasSlowSelectorNthAll,

 /// Set of selector flags that may trigger a restyle as a result of any
 /// DOM mutation.
 AllSimpleRestyleFlags =
     AllSimpleRestyleFlagsForAppend | HasSlowSelectorLaterSiblings,

 // This node was evaluated as an anchor for a relative selector.
 RelativeSelectorAnchor = 1 << 6,

 // This node was evaluated as an anchor for a relative selector, and that
 // relative selector was not the subject of the overall selector.
 RelativeSelectorAnchorNonSubject = 1 << 7,

 // This node's sibling(s) performed a relative selector search to this node.
 RelativeSelectorSearchDirectionSibling = 1 << 8,

 // This node's ancestor(s) performed a relative selector search to this node.
 RelativeSelectorSearchDirectionAncestor = 1 << 9,

 // This node's sibling(s) and ancestor(s), and/or this node's ancestor's
 // sibling(s) performed a relative selector search to this node.
 RelativeSelectorSearchDirectionAncestorSibling =
     RelativeSelectorSearchDirectionSibling |
     RelativeSelectorSearchDirectionAncestor,
};

MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(NodeSelectorFlags);

enum class BatchRemovalOrder {
 FrontToBack,
 BackToFront,
};

struct BatchRemovalState {
 // Whether we're the fist kid getting removed in the batch. Note that that's
 // different to whether we're the first _child_, if we're removing
 // back-to-front.
 bool mIsFirst = true;
};

// Make sure we have space for our bits
#define ASSERT_NODE_FLAGS_SPACE(n)                         \
 static_assert(WRAPPER_CACHE_FLAGS_BITS_USED + (n) <=     \
                   sizeof(nsWrapperCache::FlagsType) * 8, \
               "Not enough space for our bits")
ASSERT_NODE_FLAGS_SPACE(NODE_TYPE_SPECIFIC_BITS_OFFSET);

/**
* Class used to detect unexpected mutations. To use the class create an
* nsMutationGuard on the stack before unexpected mutations could occur.
* You can then at any time call Mutated to check if any unexpected mutations
* have occurred.
*/
class nsMutationGuard {
public:
 nsMutationGuard() { mStartingGeneration = sGeneration; }

 /**
  * Returns true if any unexpected mutations have occurred. You can pass in
  * an 8-bit ignore count to ignore a number of expected mutations.
  *
  * We don't need to care about overflow because subtraction of uint64_t's is
  * finding the difference between two elements of the group Z < 2^64.  Once
  * we know the difference between two elements we only need to check that is
  * less than the given number of mutations to know less than that many
  * mutations occured.  Assuming constant 1ns mutations it would take 584
  * years for sGeneration to fully wrap around so we can ignore a guard living
  * through a full wrap around.
  */
 bool Mutated(uint8_t aIgnoreCount) const {
   return (sGeneration - mStartingGeneration) > aIgnoreCount;
 }

 // This function should be called whenever a mutation that we want to keep
 // track of happen. For now this is only done when children are added or
 // removed, but we might do it for attribute changes too in the future.
 static void DidMutate() { sGeneration++; }

private:
 // This is the value sGeneration had when the guard was constructed.
 uint64_t mStartingGeneration;

 // This value is incremented on every mutation, for the life of the process.
 static uint64_t sGeneration;
};

/**
* A class that implements nsIWeakReference
*/
class nsNodeWeakReference final : public nsIWeakReference {
public:
 explicit nsNodeWeakReference(nsINode* aNode);

 // nsISupports
 NS_DECL_ISUPPORTS

 // nsIWeakReference
 NS_DECL_NSIWEAKREFERENCE

 void NoticeNodeDestruction() { mObject = nullptr; }

private:
 ~nsNodeWeakReference();
};

// This should be used for any nsINode sub-class that has fields of its own
// that it needs to measure; any sub-class that doesn't use it will inherit
// AddSizeOfExcludingThis from its super-class. AddSizeOfIncludingThis() need
// not be defined, it is inherited from nsINode.
#define NS_DECL_ADDSIZEOFEXCLUDINGTHIS                       \
 virtual void AddSizeOfExcludingThis(nsWindowSizes& aSizes, \
                                     size_t* aNodeSize) const override;

// IID for the nsINode interface
// Must be kept in sync with xpcom/rust/xpcom/src/interfaces/nonidl.rs
#define NS_INODE_IID \
 {0x70ba4547, 0x7699, 0x44fc, {0xb3, 0x20, 0x52, 0xdb, 0xe3, 0xd1, 0xf9, 0x0a}}

/**
* An internal interface that abstracts some DOMNode-related parts that both
* nsIContent and Document share.  An instance of this interface has a list
* of nsIContent children and provides access to them.
*/
class nsINode : public mozilla::dom::EventTarget {
#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
 void AssertInvariantsOnNodeInfoChange();
#endif
public:
 using BoxQuadOptions = mozilla::dom::BoxQuadOptions;
 using ConvertCoordinateOptions = mozilla::dom::ConvertCoordinateOptions;
 using DocGroup = mozilla::dom::DocGroup;
 using Document = mozilla::dom::Document;
 using DOMPoint = mozilla::dom::DOMPoint;
 using DOMPointInit = mozilla::dom::DOMPointInit;
 using DOMQuad = mozilla::dom::DOMQuad;
 using DOMRectReadOnly = mozilla::dom::DOMRectReadOnly;
 using OwningNodeOrString = mozilla::dom::OwningNodeOrString;
 using TextOrElementOrDocument = mozilla::dom::TextOrElementOrDocument;
 using CallerType = mozilla::dom::CallerType;
 using ErrorResult = mozilla::ErrorResult;

 // XXXbz Maybe we should codegen a class holding these constants and
 // inherit from it...
 static const auto ELEMENT_NODE = mozilla::dom::Node_Binding::ELEMENT_NODE;
 static const auto ATTRIBUTE_NODE = mozilla::dom::Node_Binding::ATTRIBUTE_NODE;
 static const auto TEXT_NODE = mozilla::dom::Node_Binding::TEXT_NODE;
 static const auto CDATA_SECTION_NODE =
     mozilla::dom::Node_Binding::CDATA_SECTION_NODE;
 static const auto ENTITY_REFERENCE_NODE =
     mozilla::dom::Node_Binding::ENTITY_REFERENCE_NODE;
 static const auto ENTITY_NODE = mozilla::dom::Node_Binding::ENTITY_NODE;
 static const auto PROCESSING_INSTRUCTION_NODE =
     mozilla::dom::Node_Binding::PROCESSING_INSTRUCTION_NODE;
 static const auto COMMENT_NODE = mozilla::dom::Node_Binding::COMMENT_NODE;
 static const auto DOCUMENT_NODE = mozilla::dom::Node_Binding::DOCUMENT_NODE;
 static const auto DOCUMENT_TYPE_NODE =
     mozilla::dom::Node_Binding::DOCUMENT_TYPE_NODE;
 static const auto DOCUMENT_FRAGMENT_NODE =
     mozilla::dom::Node_Binding::DOCUMENT_FRAGMENT_NODE;
 static const auto NOTATION_NODE = mozilla::dom::Node_Binding::NOTATION_NODE;
 static const auto MAX_NODE_TYPE = NOTATION_NODE;

 void* operator new(size_t aSize, nsNodeInfoManager* aManager);
 void* operator new(size_t aSize) = delete;
 void operator delete(void* aPtr);

 template <class T>
 using Sequence = mozilla::dom::Sequence<T>;

 NS_INLINE_DECL_STATIC_IID(NS_INODE_IID)

 // The |aNodeSize| outparam on this function is where the actual node size
 // value is put. It gets added to the appropriate value within |aSizes| by
 // AddSizeOfNodeTree().
 //
 // Among the sub-classes that inherit (directly or indirectly) from nsINode,
 // measurement of the following members may be added later if DMD finds it is
 // worthwhile:
 // - nsGenericHTMLElement:  mForm, mFieldSet
 // - nsGenericHTMLFrameElement: mFrameLoader (bug 672539)
 // - HTMLBodyElement:       mContentStyleRule
 // - HTMLDataListElement:   mOptions
 // - HTMLFieldSetElement:   mElements, mDependentElements, mFirstLegend
 // - HTMLFormElement:       many!
 // - HTMLFrameSetElement:   mRowSpecs, mColSpecs
 // - HTMLInputElement:      mInputData, mFiles, mFileList, mStaticDocfileList
 // - nsHTMLMapElement:      mAreas
 // - HTMLMediaElement:      many!
 // - nsHTMLOutputElement:   mDefaultValue, mTokenList
 // - nsHTMLRowElement:      mCells
 // - nsHTMLSelectElement:   mOptions, mRestoreState
 // - nsHTMLTableElement:    mTBodies, mRows, mTableInheritedAttributes
 // - nsHTMLTableSectionElement: mRows
 // - nsHTMLTextAreaElement: mControllers, mState
 //
 // The following members don't need to be measured:
 // - nsIContent: mPrimaryFrame, because it's non-owning and measured elsewhere
 //
 virtual void AddSizeOfExcludingThis(nsWindowSizes& aSizes,
                                     size_t* aNodeSize) const;

 // SizeOfIncludingThis doesn't need to be overridden by sub-classes because
 // sub-classes of nsINode are guaranteed to be laid out in memory in such a
 // way that |this| points to the start of the allocated object, even in
 // methods of nsINode's sub-classes, so aSizes.mState.mMallocSizeOf(this) is
 // always safe to call no matter which object it was invoked on.
 void AddSizeOfIncludingThis(nsWindowSizes& aSizes, size_t* aNodeSize) const;

 friend class nsNodeWeakReference;
 friend class nsNodeSupportsWeakRefTearoff;
 friend class AttrArray;

#ifdef MOZILLA_INTERNAL_API
 explicit nsINode(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
#endif

 virtual ~nsINode();

 bool IsContainerNode() const {
   return IsElement() || IsDocument() || IsDocumentFragment();
 }

 /**
  * Returns true if the node is a HTMLTemplate element.
  */
 bool IsTemplateElement() const { return IsHTMLElement(nsGkAtoms::_template); }

 bool IsSlotable() const { return IsElement() || IsText(); }

 /**
  * Returns true if this is a document node.
  */
 bool IsDocument() const {
   // One less pointer-chase than checking NodeType().
   return !GetParentNode() && IsInUncomposedDoc();
 }

 /**
  * Return this node as a document. Asserts IsDocument().
  *
  * This is defined inline in Document.h.
  */
 inline Document* AsDocument();
 inline const Document* AsDocument() const;

 /**
  * Returns true if this is a document fragment node.
  */
 bool IsDocumentFragment() const {
   return NodeType() == DOCUMENT_FRAGMENT_NODE;
 }

 virtual bool IsHTMLFormControlElement() const { return false; }

 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-descendant
  *
  * @param aNode must not be nullptr.
  */
 bool IsInclusiveDescendantOf(const nsINode* aNode) const;

 /**
  * https://dom.spec.whatwg.org/#concept-shadow-including-descendant
  *
  * @param aNode must not be nullptr.
  */
 bool IsShadowIncludingDescendantOf(const nsINode* aNode) const;

 /**
  * https://dom.spec.whatwg.org/#concept-shadow-including-inclusive-descendant
  *
  * @param aNode must not be nullptr.
  */
 bool IsShadowIncludingInclusiveDescendantOf(const nsINode* aNode) const;

 /**
  * Returns true if the given node is this node or one of its descendants
  * in the "flat tree."
  *
  * @param aNode must not be nullptr.
  */
 bool IsInclusiveFlatTreeDescendantOf(const nsINode* aNode) const;

 /**
  * Return this node as a document fragment. Asserts IsDocumentFragment().
  *
  * This is defined inline in DocumentFragment.h.
  */
 inline mozilla::dom::DocumentFragment* AsDocumentFragment();
 inline const mozilla::dom::DocumentFragment* AsDocumentFragment() const;

 JSObject* WrapObject(JSContext*, JS::Handle<JSObject*> aGivenProto) final;

 /**
  * Hook for constructing JS::ubi::Concrete specializations for memory
  * reporting. Specializations are defined in NodeUbiReporting.h.
  */
 virtual void ConstructUbiNode(void* storage) = 0;

 /**
  * returns true if we are in priviliged code or
  * layout.css.getBoxQuads.enabled == true.
  */
 static bool HasBoxQuadsSupport(JSContext* aCx, JSObject* /* unused */);

protected:
 /**
  * WrapNode is called from WrapObject to actually wrap this node, WrapObject
  * does some additional checks and fix-up that's common to all nodes. WrapNode
  * should just call the DOM binding's Wrap function.
  *
  * aGivenProto is the prototype to use (or null if the default one should be
  * used) and should just be passed directly on to the DOM binding's Wrap
  * function.
  */
 virtual JSObject* WrapNode(JSContext* aCx,
                            JS::Handle<JSObject*> aGivenProto) = 0;

public:
 mozilla::dom::ParentObject GetParentObject()
     const;  // Implemented in Document.h

 /**
  * Returns the first child of a node or the first child of
  * a template element's content if the provided node is a
  * template element.
  */
 nsIContent* GetFirstChildOfTemplateOrNode();

 /**
  * Return the scope chain parent for this node, for use in things
  * like event handler compilation.  Returning null means to use the
  * global object as the scope chain parent.
  */
 virtual nsINode* GetScopeChainParent() const;

 MOZ_CAN_RUN_SCRIPT mozilla::dom::Element* GetParentFlexElement();

 /**
  * Returns the nearest inclusive open popover for a given node, see
  * https://html.spec.whatwg.org/multipage/popover.html#nearest-inclusive-open-popover
  */
 mozilla::dom::Element* GetNearestInclusiveOpenPopover() const;

 /**
  * https://html.spec.whatwg.org/multipage/popover.html#nearest-inclusive-target-popover-for-invoker
  */
 mozilla::dom::Element* GetNearestInclusiveTargetPopoverForInvoker() const;

 nsGenericHTMLElement* GetEffectiveCommandForElement() const;

 /**
  * https://html.spec.whatwg.org/multipage/popover.html#popover-target-element
  */
 nsGenericHTMLElement* GetEffectivePopoverTargetElement() const;

 /**
  * https://html.spec.whatwg.org/multipage/popover.html#topmost-clicked-popover
  */
 mozilla::dom::Element* GetTopmostClickedPopover() const;

 /**
  * https://html.spec.whatwg.org/multipage/interactive-elements.html#nearest-clicked-dialog
  */
 mozilla::dom::HTMLDialogElement* NearestClickedDialog(mozilla::WidgetEvent*);

 bool IsNode() const final { return true; }

 NS_IMPL_FROMEVENTTARGET_HELPER(nsINode, IsNode())

 /**
  * Return whether the node is an Element node. Faster than using `NodeType()`.
  */
 bool IsElement() const { return GetBoolFlag(NodeIsElement); }

 virtual bool IsTextControlElement() const { return false; }
 virtual bool IsGenericHTMLFormControlElementWithState() const {
   return false;
 }

 // Returns non-null if this element subclasses `LinkStyle`.
 virtual const mozilla::dom::LinkStyle* AsLinkStyle() const { return nullptr; }
 mozilla::dom::LinkStyle* AsLinkStyle() {
   return const_cast<mozilla::dom::LinkStyle*>(
       static_cast<const nsINode*>(this)->AsLinkStyle());
 }

 /**
  * Return this node as an Element.  Should only be used for nodes
  * for which IsElement() is true.  This is defined inline in Element.h.
  */
 inline mozilla::dom::Element* AsElement();
 inline const mozilla::dom::Element* AsElement() const;

 /**
  * Return whether the node is an nsStyledElement instance or not.
  */
 virtual bool IsStyledElement() const { return false; }

 /**
  * Return this node as nsIContent.  Should only be used for nodes for which
  * IsContent() is true.
  *
  * The assertion in nsIContent's constructor makes this safe.
  */
 nsIContent* AsContent() {
   MOZ_ASSERT(IsContent());
   return reinterpret_cast<nsIContent*>(this);
 }
 const nsIContent* AsContent() const {
   MOZ_ASSERT(IsContent());
   return reinterpret_cast<const nsIContent*>(this);
 }

 /*
  * Return whether the node is a Text node (which might be an actual
  * textnode, or might be a CDATA section).
  */
 bool IsText() const {
   uint32_t nodeType = NodeType();
   return nodeType == TEXT_NODE || nodeType == CDATA_SECTION_NODE;
 }

 /**
  * Return this node as Text if it is one, otherwise null.  This is defined
  * inline in Text.h.
  */
 inline mozilla::dom::Text* GetAsText();
 inline const mozilla::dom::Text* GetAsText() const;

 /**
  * Return this node as Text.  Asserts IsText().  This is defined inline in
  * Text.h.
  */
 inline mozilla::dom::Text* AsText();
 inline const mozilla::dom::Text* AsText() const;

 /**
  * Return this node if the instance type inherits nsIFormControl, or an
  * nsIFormControl instance which ia associated with this node.  Otherwise,
  * returns nullptr.
  */
 [[nodiscard]] virtual nsIFormControl* GetAsFormControl() { return nullptr; }
 [[nodiscard]] virtual const nsIFormControl* GetAsFormControl() const {
   return nullptr;
 }

 /*
  * Return whether the node is a ProcessingInstruction node.
  */
 bool IsProcessingInstruction() const {
   return NodeType() == PROCESSING_INSTRUCTION_NODE;
 }

 /*
  * Return whether the node is a CharacterData node (text, cdata,
  * comment, processing instruction)
  */
 bool IsCharacterData() const {
   uint32_t nodeType = NodeType();
   return nodeType == TEXT_NODE || nodeType == CDATA_SECTION_NODE ||
          nodeType == PROCESSING_INSTRUCTION_NODE || nodeType == COMMENT_NODE;
 }

 /**
  * Return whether the node is a Comment node.
  */
 bool IsComment() const { return NodeType() == COMMENT_NODE; }

 /**
  * Return whether the node is an Attr node.
  */
 bool IsAttr() const { return NodeType() == ATTRIBUTE_NODE; }

 /**
  * Return if this node has any children.
  */
 bool HasChildren() const { return !!mFirstChild; }

 /**
  * Get the number of children
  * @return the number of children
  */
 uint32_t GetChildCount() const { return mChildCount; }

 /** Get the number of flat tree children */
 uint32_t GetFlatTreeChildCount() const;

 /**
  * NOTE: this function is going to be removed soon (hopefully!) Don't use it
  * in new code.
  *
  * Get a child by index
  * @param aIndex the index of the child to get
  * @return the child, or null if index out of bounds
  */
 nsIContent* GetChildAt_Deprecated(uint32_t aIndex) const;

 /** Get the child at aIndex in flat tree **/
 nsINode* GetChildAtInFlatTree(uint32_t aIndex) const;

 /**
  * Get the index of a child within this content.
  *
  * @param aPossibleChild the child to get the index of.
  * @return the index of the child, or Nothing if not a child. Be aware that
  *         anonymous children (e.g. a <div> child of an <input> element) will
  *         result in Nothing.
  *
  * If the return value is Some, then calling GetChildAt_Deprecated() with
  * that value will return aPossibleChild.
  */
 mozilla::Maybe<uint32_t> ComputeIndexOf(const nsINode* aPossibleChild) const;

 /**
  * Return true if ComputeIndexOf() may cache the computed index for further
  * calls.
  */
 [[nodiscard]] bool MaybeCachesComputedIndex() const;

 /**
  * Get the index of a child within this content's flat tree children.
  *
  * @param aPossibleChild the child to get the index of.
  * @return the index of the child, or Nothing if not a child. Be aware that
  *         anonymous children (e.g. a <div> child of an <input> element) will
  *         result in Nothing.
  */
 mozilla::Maybe<uint32_t> ComputeFlatTreeIndexOf(
     const nsINode* aPossibleChild) const;

 /**
  * Get the index of this within parent node (ComputeIndexInParentNode) or
  * parent content (nsIContent) node (ComputeIndexInParentContent).
  *
  * @return the index of this node in the parent, or Nothing there is no
  *         parent (content) node or the parent does not have this node anymore
  *         (e.g., being removed from the parent). Be aware that anonymous
  *         children (e.g. a <div> child of an <input> element) will result in
  *         Nothing.
  *
  * If the return value is Some, then calling GetChildAt_Deprecated() with
  * that value will return this.
  */
 mozilla::Maybe<uint32_t> ComputeIndexInParentNode() const;
 mozilla::Maybe<uint32_t> ComputeIndexInParentContent() const;

 /**
  * Return true if the parent node may cache the computed index for further
  * calls.
  */
 [[nodiscard]] bool MaybeParentCachesComputedIndex() const;

 /**
  * Get the index of a child within this content.
  *
  * @param aPossibleChild the child to get the index of.
  * @return the index of the child, or -1 if not a child. Be aware that
  *         anonymous children (e.g. a <div> child of an <input> element) will
  *         result in -1.
  *
  * If the return value is not -1, then calling GetChildAt_Deprecated() with
  * that value will return aPossibleChild.
  */
 int32_t ComputeIndexOf_Deprecated(const nsINode* aPossibleChild) const;

 /**
  * Returns the "node document" of this node.
  *
  * https://dom.spec.whatwg.org/#concept-node-document
  *
  * Note that in the case that this node is a document node this method
  * will return |this|.  That is different to the Node.ownerDocument DOM
  * attribute (implemented by nsINode::GetOwnerDocument) which is specified to
  * be null in that case:
  *
  * https://dom.spec.whatwg.org/#dom-node-ownerdocument
  *
  * For all other cases OwnerDoc and GetOwnerDocument behave identically.
  */
 Document* OwnerDoc() const MOZ_NONNULL_RETURN {
   return mNodeInfo->GetDocument();
 }

 /**
  * Return the "owner document" of this node as an nsINode*.  Implemented
  * in Document.h.
  */
 inline nsINode* OwnerDocAsNode() const MOZ_NONNULL_RETURN;

 /**
  * Returns true if the content has an ancestor that is a document.
  *
  * @return whether this content is in a document tree
  */
 bool IsInUncomposedDoc() const { return GetBoolFlag(IsInDocument); }

 /**
  * Get the document that this content is currently in, if any. This will be
  * null if the content has no ancestor that is a document.
  *
  * @return the current document
  */

 Document* GetUncomposedDoc() const {
   return IsInUncomposedDoc() ? OwnerDoc() : nullptr;
 }

 /**
  * Returns true if we're connected, and thus GetComposedDoc() would return a
  * non-null value.
  */
 bool IsInComposedDoc() const { return GetBoolFlag(IsConnected); }

 /**
  * This method returns the owner document if the node is connected to it
  * (as defined in the DOM spec), otherwise it returns null.
  * In other words, returns non-null even in the case the node is in
  * Shadow DOM, if there is a possibly shadow boundary crossing path from
  * the node to its owner document.
  */
 Document* GetComposedDoc() const {
   return IsInComposedDoc() ? OwnerDoc() : nullptr;
 }

 /**
  * Returns OwnerDoc() if the node is in uncomposed document and ShadowRoot if
  * the node is in Shadow DOM.
  */
 mozilla::dom::DocumentOrShadowRoot* GetContainingDocumentOrShadowRoot() const;

 /**
  * Returns OwnerDoc() if the node is in uncomposed document and ShadowRoot if
  * the node is in Shadow DOM and is in composed document.
  */
 mozilla::dom::DocumentOrShadowRoot* GetUncomposedDocOrConnectedShadowRoot()
     const;

 /**
  * To be called when reference count of the node drops to zero.
  */
 void LastRelease();

 /**
  * The values returned by this function are the ones defined for
  * Node.nodeType
  */
 uint16_t NodeType() const { return mNodeInfo->NodeType(); }
 const nsString& NodeName() const { return mNodeInfo->NodeName(); }
 const nsString& LocalName() const { return mNodeInfo->LocalName(); }

 /**
  * Get the NodeInfo for this element
  * @return the nodes node info
  */
 inline mozilla::dom::NodeInfo* NodeInfo() const { return mNodeInfo; }

 /**
  * Called when we have been adopted, and the information of the
  * node has been changed.
  *
  * The new document can be reached via OwnerDoc().
  *
  * If you override this method,
  * please call up to the parent NodeInfoChanged.
  *
  * If you change this, change also the similar method in Link.
  */
 virtual void NodeInfoChanged(Document* aOldDoc) {
#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
   AssertInvariantsOnNodeInfoChange();
#endif
 }

 inline bool IsInNamespace(int32_t aNamespace) const {
   return mNodeInfo->NamespaceID() == aNamespace;
 }

 /**
  * Returns the DocGroup of the "node document" of this node.
  */
 DocGroup* GetDocGroup() const;

 /**
  * Print a debugger friendly descriptor of this element. This will describe
  * the position of this element in the document.
  */
 friend std::ostream& operator<<(std::ostream& aStream, const nsINode& aNode);

protected:
 // These 2 methods are useful for the recursive templates IsHTMLElement,
 // IsSVGElement, etc.
 inline bool IsNodeInternal() const { return false; }

 template <typename First, typename... Args>
 inline bool IsNodeInternal(First aFirst, Args... aArgs) const {
   return mNodeInfo->Equals(aFirst) || IsNodeInternal(aArgs...);
 }

public:
 inline bool IsHTMLElement() const {
   return IsElement() && IsInNamespace(kNameSpaceID_XHTML);
 }

 inline bool IsHTMLElement(const nsAtom* aTag) const {
   return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_XHTML);
 }

 template <typename First, typename... Args>
 inline bool IsAnyOfHTMLElements(First aFirst, Args... aArgs) const {
   return IsHTMLElement() && IsNodeInternal(aFirst, aArgs...);
 }

 inline bool IsSVGElement() const {
   return IsElement() && IsInNamespace(kNameSpaceID_SVG);
 }

 inline bool IsSVGElement(const nsAtom* aTag) const {
   return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_SVG);
 }

 template <typename First, typename... Args>
 inline bool IsAnyOfSVGElements(First aFirst, Args... aArgs) const {
   return IsSVGElement() && IsNodeInternal(aFirst, aArgs...);
 }

 virtual bool IsSVGAnimationElement() const { return false; }
 virtual bool IsSVGComponentTransferFunctionElement() const { return false; }
 virtual bool IsSVGFilterPrimitiveElement() const { return false; }
 virtual bool IsSVGFilterPrimitiveChildElement() const { return false; }
 virtual bool IsSVGGeometryElement() const { return false; }
 virtual bool IsSVGGraphicsElement() const { return false; }

 inline bool IsXULElement() const {
   return IsElement() && IsInNamespace(kNameSpaceID_XUL);
 }

 inline bool IsXULElement(const nsAtom* aTag) const {
   return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_XUL);
 }

 template <typename First, typename... Args>
 inline bool IsAnyOfXULElements(First aFirst, Args... aArgs) const {
   return IsXULElement() && IsNodeInternal(aFirst, aArgs...);
 }

 inline bool IsMathMLElement() const {
   return IsElement() && IsInNamespace(kNameSpaceID_MathML);
 }

 inline bool IsMathMLElement(const nsAtom* aTag) const {
   return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_MathML);
 }

 template <typename First, typename... Args>
 inline bool IsAnyOfMathMLElements(First aFirst, Args... aArgs) const {
   return IsMathMLElement() && IsNodeInternal(aFirst, aArgs...);
 }

 bool IsShadowRoot() const {
   const bool isShadowRoot = IsInShadowTree() && !GetParentNode();
   MOZ_ASSERT_IF(isShadowRoot, IsDocumentFragment());
   return isShadowRoot;
 }

 bool IsHTMLHeadingElement() const {
   return IsAnyOfHTMLElements(nsGkAtoms::h1, nsGkAtoms::h2, nsGkAtoms::h3,
                              nsGkAtoms::h4, nsGkAtoms::h5, nsGkAtoms::h6);
 }

 /**
  * Check whether the conditional processing attributes other than
  * systemLanguage "return true" if they apply to and are specified
  * on the given SVG element. Returns true if this element should be
  * rendered, false if it should not.
  */
 virtual bool PassesConditionalProcessingTests() const { return true; }

 /**
  * Insert a content node before another or at the end.
  * This method handles calling BindToTree on the child appropriately.
  *
  * @param aKid the content to insert
  * @param aBeforeThis an existing node. Use nullptr if you want to
  *        add aKid at the end.
  * @param aNotify whether to notify the document (current document for
  *        nsIContent, and |this| for Document) that the insert has occurred
  * @param aRv The error, if any.
  *        Throw NS_ERROR_DOM_HIERARCHY_REQUEST_ERR if one attempts to have
  *        more than one element node as a child of a document.  Doing this
  *        will also assert -- you shouldn't be doing it!  Check with
  *        Document::GetRootElement() first if you're not sure.  Apart from
  *        this one constraint, this doesn't do any checking on whether aKid is
  *        a valid child of |this|.
  *        Throw NS_ERROR_OUT_OF_MEMORY in some cases (from BindToTree).
  * @param aOldParent In case the method is called as part of moveBefore,
  *        the argument tells which node used to be the parent of aKid.
  * @param aMutationEffectOnScript Indicate how this change after
  *        trustworthiness of parent script.
  */
 virtual void InsertChildBefore(
     nsIContent* aKid, nsIContent* aBeforeThis, bool aNotify,
     mozilla::ErrorResult& aRv, nsINode* aOldParent = nullptr,
     MutationEffectOnScript aMutationEffectOnScript =
         MutationEffectOnScript::DropTrustWorthiness);

 /**
  * Append a content node to the end of the child list.  This method handles
  * calling BindToTree on the child appropriately.
  *
  * @param aKid the content to append
  * @param aNotify whether to notify the document (current document for
  *        nsIContent, and |this| for Document) that the append has occurred
  * @param aRv The error, if any.
  *        Throw NS_ERROR_DOM_HIERARCHY_REQUEST_ERR if one attempts to have
  *        more than one element node as a child of a document.  Doing this
  *        will also assert -- you shouldn't be doing it!  Check with
  *        Document::GetRootElement() first if you're not sure.  Apart from
  *        this one constraint, this doesn't do any checking on whether aKid is
  *        a valid child of |this|.
  *        Throw NS_ERROR_OUT_OF_MEMORY in some cases (from BindToTree).
  * @param aMutationEffectOnScript Indicate how this change after
  *        trustworthiness of parent script.
  */
 void AppendChildTo(nsIContent* aKid, bool aNotify, mozilla::ErrorResult& aRv,
                    MutationEffectOnScript aMutationEffectOnScript =
                        MutationEffectOnScript::DropTrustWorthiness) {
   InsertChildBefore(aKid, nullptr, aNotify, aRv, nullptr,
                     aMutationEffectOnScript);
 }

 template <BatchRemovalOrder aOrder = BatchRemovalOrder::FrontToBack>
 void RemoveAllChildren(bool aNotify) {
   BatchRemovalState state{};
   while (HasChildren()) {
     nsIContent* nodeToRemove = aOrder == BatchRemovalOrder::FrontToBack
                                    ? GetFirstChild()
                                    : GetLastChild();
     RemoveChildNode(nodeToRemove, aNotify, &state, nullptr,
                     MutationEffectOnScript::KeepTrustWorthiness);
     state.mIsFirst = false;
   }
 }

 /**
  * Remove a child from this node.  This method handles calling UnbindFromTree
  * on the child appropriately.
  *
  * @param aKid the content to remove
  * @param aNotify whether to notify the document (current document for
  *        nsIContent, and |this| for Document) that the remove has occurred
  * @param BatchRemovalState The current state of our batch removal.
  * @param aNewParent In case the method is called as part of moveBefore,
  *        the argument tells which node will be aKid's new parent.
  * @param aMutationEffectOnScript Indicate how this change after
  *        trustworthiness of parent script.
  */
 virtual void RemoveChildNode(nsIContent* aKid, bool aNotify,
                              const BatchRemovalState* = nullptr,
                              nsINode* aNewParent = nullptr,
                              MutationEffectOnScript aMutationEffectOnScript =
                                  MutationEffectOnScript::DropTrustWorthiness);

 /**
  * Get a property associated with this node.
  *
  * @param aPropertyName  name of property to get.
  * @param aStatus        out parameter for storing resulting status.
  *                       Set to NS_PROPTABLE_PROP_NOT_THERE if the property
  *                       is not set.
  * @return               the property. Null if the property is not set
  *                       (though a null return value does not imply the
  *                       property was not set, i.e. it can be set to null).
  */
 void* GetProperty(const nsAtom* aPropertyName,
                   nsresult* aStatus = nullptr) const;

 /**
  * Set a property to be associated with this node. This will overwrite an
  * existing value if one exists. The existing value is destroyed using the
  * destructor function given when that value was set.
  *
  * @param aPropertyName  name of property to set.
  * @param aValue         new value of property.
  * @param aDtor          destructor function to be used when this property
  *                       is destroyed.
  * @param aTransfer      if true the property will not be deleted when the
  *                       ownerDocument of the node changes, if false it
  *                       will be deleted.
  *
  * @return NS_PROPTABLE_PROP_OVERWRITTEN (success value) if the property
  *                                       was already set
  * @throws NS_ERROR_OUT_OF_MEMORY if that occurs
  */
 nsresult SetProperty(nsAtom* aPropertyName, void* aValue,
                      NSPropertyDtorFunc aDtor = nullptr,
                      bool aTransfer = false);

 /**
  * A generic destructor for property values allocated with new.
  */
 template <class T>
 static void DeleteProperty(void*, nsAtom*, void* aPropertyValue, void*) {
   delete static_cast<T*>(aPropertyValue);
 }

 /**
  * Removes a property associated with this node. The value is destroyed using
  * the destruction function given when that value was set.
  *
  * @param aPropertyName  name of property to destroy.
  */
 void RemoveProperty(const nsAtom* aPropertyName);

 /**
  * Take a property associated with this node. The value will not be destroyed
  * but rather returned. It is the caller's responsibility to destroy the value
  * after that point.
  *
  * @param aPropertyName  name of property to unset.
  * @param aStatus        out parameter for storing resulting status.
  *                       Set to NS_PROPTABLE_PROP_NOT_THERE if the property
  *                       is not set.
  * @return               the property. Null if the property is not set
  *                       (though a null return value does not imply the
  *                       property was not set, i.e. it can be set to null).
  */
 void* TakeProperty(const nsAtom* aPropertyName, nsresult* aStatus = nullptr);

 bool HasProperties() const { return HasFlag(NODE_HAS_PROPERTIES); }

 /**
  * Return the principal of this node.  This is guaranteed to never be a null
  * pointer.
  */
 nsIPrincipal* NodePrincipal() const {
   return mNodeInfo->NodeInfoManager()->DocumentPrincipal();
 }

 /**
  * Return the Policy Container of this node's document, if any.
  */
 nsIPolicyContainer* GetPolicyContainer() const;

 /**
  * Get the parent nsIContent for this node.
  * @return the parent, or null if no parent or the parent is not an nsIContent
  */
 nsIContent* GetParent() const {
   return MOZ_LIKELY(GetBoolFlag(ParentIsContent)) ? mParent->AsContent()
                                                   : nullptr;
 }

 /**
  * Get the parent nsINode for this node. This can be either an nsIContent, a
  * Document or an Attr.
  * @return the parent node
  */
 nsINode* GetParentNode() const { return mParent; }

private:
 nsIContent* DoGetShadowHost() const;

public:
 nsINode* GetParentOrShadowHostNode() const {
   if (MOZ_LIKELY(mParent)) {
     return mParent;
   }
   // We could put this in nsIContentInlines.h or such to avoid this
   // reinterpret_cast, but it doesn't seem worth it.
   return IsInShadowTree() ? reinterpret_cast<nsINode*>(DoGetShadowHost())
                           : nullptr;
 }

 enum FlattenedParentType { eNormal, eForStyle, eForSelection };

 /**
  * Returns the node that is the parent of this node in the flattened
  * tree. This differs from the normal parent if the node is filtered
  * into an insertion point, or if the node is a direct child of a
  * shadow root.
  *
  * @return the flattened tree parent
  */
 inline nsINode* GetFlattenedTreeParentNode() const;

 nsINode* GetFlattenedTreeParentNodeNonInline() const;

 /**
  * Like GetFlattenedTreeParentNode, but returns the document for any native
  * anonymous content that was generated for ancestor frames of the document
  * element's primary frame, such as scrollbar elements created by the root
  * scroll frame.
  */
 inline nsINode* GetFlattenedTreeParentNodeForStyle() const;

 /**
  * Similar to GetFlattenedTreeParentNode, it does two things differently
  *   1. For contents that are not in the flattened tree, use its
  *   parent rather than nullptr.
  *   2. For contents that are slotted into a UA shadow tree, use its
  *   parent rather than the slot element.
  */
 inline nsINode* GetFlattenedTreeParentNodeForSelection() const;

 inline mozilla::dom::Element* GetFlattenedTreeParentElement() const;
 inline mozilla::dom::Element* GetFlattenedTreeParentElementForStyle() const;

 /**
  * Get the parent nsINode for this node if it is an Element.
  *
  * Defined inline in Element.h
  *
  * @return the parent node
  */
 inline mozilla::dom::Element* GetParentElement() const;

 /**
  * Get the parent Element of this node, traversing over a ShadowRoot
  * to its host if necessary.
  */
 mozilla::dom::Element* GetParentElementCrossingShadowRoot() const;

 /**
  * Get closest element node for the node.  Meaning that if the node is an
  * element node, returns itself.  Otherwise, returns parent element or null.
  * Note that if the node is a non-element node and it's root of a shadow DOM,
  * this returns nullptr.  If you want to get inclusive flattened tree ancestor
  * in this case, use GetInclusiveFlattenedTreeAncestorElement().
  */
 inline mozilla::dom::Element* GetAsElementOrParentElement() const;

 /**
  * Get inclusive ancestor element in the flattened tree.
  */
 inline mozilla::dom::Element* GetInclusiveFlattenedTreeAncestorElement()
     const;

 /**
  * Get the root of the subtree this node belongs to.  This never returns
  * null.  It may return 'this' (e.g. for document nodes, and nodes that
  * are the roots of disconnected subtrees).
  */
 nsINode* SubtreeRoot() const;

 /*
  * Get context object's shadow-including root if options's composed is true,
  * and context object's root otherwise.
  */
 nsINode* GetRootNode(const mozilla::dom::GetRootNodeOptions& aOptions);

 virtual mozilla::EventListenerManager* GetExistingListenerManager()
     const override;
 virtual mozilla::EventListenerManager* GetOrCreateListenerManager() override;

 mozilla::Maybe<mozilla::dom::EventCallbackDebuggerNotificationType>
 GetDebuggerNotificationType() const override;

 bool ComputeDefaultWantsUntrusted(mozilla::ErrorResult& aRv) final;

 virtual bool IsApzAware() const override;

 virtual nsPIDOMWindowOuter* GetOwnerGlobalForBindingsInternal() override;
 virtual nsIGlobalObject* GetOwnerGlobal() const override;

 using mozilla::dom::EventTarget::DispatchEvent;
 // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
 MOZ_CAN_RUN_SCRIPT_BOUNDARY bool DispatchEvent(
     mozilla::dom::Event& aEvent, mozilla::dom::CallerType aCallerType,
     mozilla::ErrorResult& aRv) override;

 MOZ_CAN_RUN_SCRIPT
 nsresult PostHandleEvent(mozilla::EventChainPostVisitor& aVisitor) override;

 /**
  * Adds a mutation observer to be notified when this node, or any of its
  * descendants, are modified. The node will hold a weak reference to the
  * observer, which means that it is the responsibility of the observer to
  * remove itself in case it dies before the node.  If an observer is added
  * while observers are being notified, it may also be notified.  In general,
  * adding observers while inside a notification is not a good idea.  An
  * observer that is already observing the node must not be added without
  * being removed first.
  *
  * For mutation observers that implement nsIAnimationObserver, use
  * AddAnimationObserver instead.
  */
 void AddMutationObserver(nsIMutationObserver* aMutationObserver) {
   nsSlots* s = Slots();
   if (aMutationObserver) {
     NS_ASSERTION(!s->mMutationObservers.contains(aMutationObserver),
                  "Observer already in the list");

     s->mMutationObservers.pushBack(aMutationObserver);
   }
 }

 void AddMutationObserver(nsMultiMutationObserver* aMultiMutationObserver);

 /**
  * Same as above, but only adds the observer if its not observing
  * the node already.
  *
  * For mutation observers that implement nsIAnimationObserver, use
  * AddAnimationObserverUnlessExists instead.
  */
 void AddMutationObserverUnlessExists(nsIMutationObserver* aMutationObserver) {
   nsSlots* s = Slots();
   if (aMutationObserver &&
       !s->mMutationObservers.contains(aMutationObserver)) {
     s->mMutationObservers.pushBack(aMutationObserver);
   }
 }

 void AddMutationObserverUnlessExists(
     nsMultiMutationObserver* aMultiMutationObserver);
 /**
  * Same as AddMutationObserver, but for nsIAnimationObservers.  This
  * additionally records on the document that animation observers have
  * been registered, which is used to determine whether notifications
  * must be fired when animations are added, removed or changed.
  */
 void AddAnimationObserver(nsIAnimationObserver* aAnimationObserver);

 /**
  * Same as above, but only adds the observer if its not observing
  * the node already.
  */
 void AddAnimationObserverUnlessExists(
     nsIAnimationObserver* aAnimationObserver);

 /**
  * Removes a mutation observer.
  */
 void RemoveMutationObserver(nsIMutationObserver* aMutationObserver) {
   nsSlots* s = GetExistingSlots();
   if (s) {
     s->mMutationObservers.remove(aMutationObserver);
   }
 }

 void RemoveMutationObserver(nsMultiMutationObserver* aMultiMutationObserver);

 mozilla::SafeDoublyLinkedList<nsIMutationObserver>* GetMutationObservers();

 /**
  * Helper methods to access ancestor node(s) of type T.
  * The implementations of the methods are in mozilla/dom/AncestorIterator.h.
  */
 template <typename T>
 inline mozilla::dom::AncestorsOfTypeIterator<T> AncestorsOfType() const;

 template <typename T>
 inline mozilla::dom::InclusiveAncestorsOfTypeIterator<T>
 InclusiveAncestorsOfType() const;

 template <typename T>
 inline mozilla::dom::FlatTreeAncestorsOfTypeIterator<T>
 FlatTreeAncestorsOfType() const;

 template <typename T>
 inline mozilla::dom::InclusiveFlatTreeAncestorsOfTypeIterator<T>
 InclusiveFlatTreeAncestorsOfType() const;

 template <typename T>
 T* FirstAncestorOfType() const;

private:
 /**
  * Walks aNode, its attributes and, if aDeep is true, its descendant nodes.
  * If aClone is true the nodes will be cloned. If aNewNodeInfoManager is
  * not null, it is used to create new nodeinfos for the nodes. Also reparents
  * the XPConnect wrappers for the nodes into aReparentScope if non-null.
  *
  * @param aNode Node to adopt/clone.
  * @param aClone If true the node will be cloned and the cloned node will
  *               be returned.
  * @param aDeep If true the function will be called recursively on
  *              descendants of the node
  * @param aNewNodeInfoManager The nodeinfo manager to use to create new
  *                            nodeinfos for aNode and its attributes and
  *                            descendants. May be null if the nodeinfos
  *                            shouldn't be changed.
  * @param aReparentScope Scope into which wrappers should be reparented, or
  *                             null if no reparenting should be done.
  * @param aParent If aClone is true the cloned node will be appended to
  *                aParent's children. May be null. If not null then aNode
  *                must be an nsIContent.
  * @param aError The error, if any.
  *
  * @return If aClone is true then the cloned node will be returned,
  *          unless an error occurred.  In error conditions, null
  *          will be returned.
  */
 static already_AddRefed<nsINode> CloneAndAdopt(
     nsINode* aNode, bool aClone, bool aDeep,
     nsNodeInfoManager* aNewNodeInfoManager,
     JS::Handle<JSObject*> aReparentScope, nsINode* aParent,
     mozilla::ErrorResult& aError);

public:
 /**
  * Walks the node, its attributes and descendant nodes. If aNewNodeInfoManager
  * is not null, it is used to create new nodeinfos for the nodes. Also
  * reparents the XPConnect wrappers for the nodes into aReparentScope if
  * non-null.
  *
  * @param aNewNodeInfoManager The nodeinfo manager to use to create new
  *                            nodeinfos for the node and its attributes and
  *                            descendants. May be null if the nodeinfos
  *                            shouldn't be changed.
  * @param aReparentScope New scope for the wrappers, or null if no reparenting
  *                       should be done.
  * @param aError The error, if any.
  */
 void Adopt(nsNodeInfoManager* aNewNodeInfoManager,
            JS::Handle<JSObject*> aReparentScope,
            mozilla::ErrorResult& aError);

 /**
  * Clones the node, its attributes and, if aDeep is true, its descendant nodes
  * If aNewNodeInfoManager is not null, it is used to create new nodeinfos for
  * the clones.
  *
  * @param aDeep If true the function will be called recursively on
  *              descendants of the node
  * @param aNewNodeInfoManager The nodeinfo manager to use to create new
  *                            nodeinfos for the node and its attributes and
  *                            descendants. May be null if the nodeinfos
  *                            shouldn't be changed.
  * @param aError The error, if any.
  *
  * @return The newly created node.  Null in error conditions.
  */
 already_AddRefed<nsINode> Clone(bool aDeep,
                                 nsNodeInfoManager* aNewNodeInfoManager,
                                 mozilla::ErrorResult& aError);

 /**
  * Clones this node. This needs to be overriden by all node classes. aNodeInfo
  * should be identical to this node's nodeInfo, except for the document which
  * may be different. When cloning an element, all attributes of the element
  * will be cloned. The children of the node will not be cloned.
  *
  * @param aNodeInfo the nodeinfo to use for the clone
  * @param aResult the clone
  */
 virtual nsresult Clone(mozilla::dom::NodeInfo*, nsINode** aResult) const = 0;

 // A callback that gets called when we are forcefully unbound from a node (due
 // to the node going away). You shouldn't take a strong ref to the node from
 // the callback.
 using UnbindCallback = void (*)(nsISupports*, nsINode*);
 // We should keep alive these objects.
 struct BoundObject {
   nsCOMPtr<nsISupports> mObject;
   UnbindCallback mDtor = nullptr;

   BoundObject(nsISupports* aObject, UnbindCallback aDtor)
       : mObject(aObject), mDtor(aDtor) {}

   bool operator==(nsISupports* aOther) const {
     return mObject.get() == aOther;
   }
 };

 // This class can be extended by subclasses that wish to store more
 // information in the slots.
 class nsSlots {
  public:
   nsSlots();

   // If needed we could remove the vtable pointer this dtor causes by
   // putting a DestroySlots function on nsINode
   virtual ~nsSlots();

   virtual void Traverse(nsCycleCollectionTraversalCallback&);
   virtual void Unlink(nsINode&);

   /**
    * A list of mutation observers
    */
   mozilla::SafeDoublyLinkedList<nsIMutationObserver> mMutationObservers;

   /**
    * An object implementing NodeList for this content (childNodes)
    * @see NodeList
    * @see nsGenericHTMLElement::GetChildNodes
    */
   RefPtr<nsAttrChildContentList> mChildNodes;

   /**
    * Weak reference to this node.  This is cleared by the destructor of
    * nsNodeWeakReference.
    */
   nsNodeWeakReference* MOZ_NON_OWNING_REF mWeakReference;

   /** A list of objects that we should keep alive. See Bind/UnbindObject. */
   nsTArray<BoundObject> mBoundObjects;

   /**
    * A set of ranges which are in the selection and which have this node as
    * their endpoints' closest common inclusive ancestor
    * (https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor).  This is
    * a UniquePtr instead of just a LinkedList, because that prevents us from
    * pushing DOMSlots up to the next allocation bucket size, at the cost of
    * some complexity.
    */
   mozilla::UniquePtr<mozilla::LinkedList<mozilla::dom::AbstractRange>>
       mClosestCommonInclusiveAncestorRanges;
 };

 /**
  * Functions for managing flags and slots
  */
#ifdef DEBUG
 nsSlots* DebugGetSlots() { return Slots(); }
#endif

 void SetFlags(FlagsType aFlagsToSet) {
   NS_ASSERTION(
       !(aFlagsToSet &
         (NODE_IS_NATIVE_ANONYMOUS_ROOT | NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE |
          NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME |
          NODE_HAS_BEEN_IN_UA_WIDGET)) ||
           IsContent(),
       "Flag only permitted on nsIContent nodes");
   nsWrapperCache::SetFlags(aFlagsToSet);
 }

 void UnsetFlags(FlagsType aFlagsToUnset) {
   NS_ASSERTION(!(aFlagsToUnset & (NODE_HAS_BEEN_IN_UA_WIDGET |
                                   NODE_IS_NATIVE_ANONYMOUS_ROOT)),
                "Trying to unset write-only flags");
   nsWrapperCache::UnsetFlags(aFlagsToUnset);
 }

 void SetEditableFlag(bool aEditable) {
   if (aEditable) {
     SetFlags(NODE_IS_EDITABLE);
   } else {
     UnsetFlags(NODE_IS_EDITABLE);
   }
 }

 inline bool IsEditable() const;

 /**
  * Check if this node is an editing host. For avoiding confusion, this always
  * returns false if the node is in the design mode document.
  */
 inline bool IsEditingHost() const;

 /**
  * Check if this node is in design mode or not.  When this returns true and:
  * - if this is a Document node, it's the design mode root.
  * - if this is a content node, it's connected, it's not in a shadow tree
  *   (except shadow tree for UI widget and native anonymous subtree) and its
  *   uncomposed document is in design mode.
  * Note that returning true does NOT mean the node or its children is
  * editable.  E.g., when this node is in a shadow tree of a UA widget and its
  * host is in design mode.
  */
 inline bool IsInDesignMode() const;

 /**
  * Returns true if |this| or any of its ancestors is native anonymous.
  */
 bool IsInNativeAnonymousSubtree() const {
   return HasFlag(NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE);
 }

 /**
  * If |this| or any ancestor is native anonymous, return the root of the
  * native anonymous subtree. Note that in case of nested native anonymous
  * content, this returns the innermost root, not the outermost.
  */
 nsIContent* GetClosestNativeAnonymousSubtreeRoot() const {
   if (!IsInNativeAnonymousSubtree()) {
     MOZ_ASSERT(!HasBeenInUAWidget(), "UA widget implies anonymous");
     return nullptr;
   }
   MOZ_ASSERT(IsContent(), "How did non-content end up in NAC?");
   if (HasBeenInUAWidget()) {
     // reinterpret_cast because in this header we don't know ShadowRoot is an
     // nsIContent. ShadowRoot constructor asserts this is correct.
     return reinterpret_cast<nsIContent*>(GetContainingShadow());
   }
   for (const nsINode* node = this; node; node = node->GetParentNode()) {
     if (node->IsRootOfNativeAnonymousSubtree()) {
       return const_cast<nsINode*>(node)->AsContent();
     }
   }
   // FIXME(emilio): This should not happen, usually, but editor removes nodes
   // in native anonymous subtrees, and we don't clean nodes from the current
   // event content stack from ContentRemoved, so it can actually happen, see
   // bug 1510208.
   NS_WARNING("GetClosestNativeAnonymousSubtreeRoot on disconnected NAC!");
   return nullptr;
 }

 /**
  * If |this| or any ancestor is native anonymous, return the parent of the
  * native anonymous subtree. Note that in case of nested native anonymous
  * content, this returns the parent or host of the innermost root, not the
  * outermost.
  */
 nsIContent* GetClosestNativeAnonymousSubtreeRootParentOrHost() const {
   // We could put this in nsIContentInlines.h or such to avoid this
   // reinterpret_cast, but it doesn't seem worth it.
   const auto* root = reinterpret_cast<const nsINode*>(
       GetClosestNativeAnonymousSubtreeRoot());
   if (!root) {
     return nullptr;
   }
   if (nsIContent* parent = root->GetParent()) {
     return parent;
   }
   if (MOZ_UNLIKELY(root->IsInShadowTree())) {
     return root->DoGetShadowHost();
   }
   return nullptr;
 }

 /**
  * Gets the root of the node tree for this content if it is in a shadow tree.
  */
 mozilla::dom::ShadowRoot* GetContainingShadow() const;
 /**
  * Gets the shadow host if this content is in a shadow tree. That is, the host
  * of |GetContainingShadow|, if its not null.
  *
  * @return The shadow host, if this is in shadow tree, or null.
  */
 mozilla::dom::Element* GetContainingShadowHost() const;

 bool IsInSVGUseShadowTree() const {
   return !!GetContainingSVGUseShadowHost();
 }

 mozilla::dom::SVGUseElement* GetContainingSVGUseShadowHost() const {
   if (!IsInShadowTree()) {
     return nullptr;
   }
   return DoGetContainingSVGUseShadowHost();
 }

 // Whether this node has ever been part of a UA widget shadow tree.
 bool HasBeenInUAWidget() const { return HasFlag(NODE_HAS_BEEN_IN_UA_WIDGET); }

 // True for native anonymous content and for content in UA widgets.
 // Only nsIContent can fulfill this condition.
 bool ChromeOnlyAccess() const { return IsInNativeAnonymousSubtree(); }

 // Whether we're chrome-only for event targeting. UA widgets can use regular
 // shadow DOM retargeting for these.
 bool ChromeOnlyAccessForEvents() const {
   return ChromeOnlyAccess() && !HasBeenInUAWidget();
 }

 bool IsInShadowTree() const { return HasFlag(NODE_IS_IN_SHADOW_TREE); }

 /**
  * Get whether this node is C++-generated anonymous content
  * @see nsIAnonymousContentCreator
  * @return whether this content is anonymous
  */
 bool IsRootOfNativeAnonymousSubtree() const {
   NS_ASSERTION(
       !HasFlag(NODE_IS_NATIVE_ANONYMOUS_ROOT) || IsInNativeAnonymousSubtree(),
       "Some flags seem to be missing!");
   return HasFlag(NODE_IS_NATIVE_ANONYMOUS_ROOT);
 }

 // Whether this node is the root of a ChromeOnlyAccess DOM subtree.
 bool IsRootOfChromeAccessOnlySubtree() const {
   return IsRootOfNativeAnonymousSubtree();
 }

 /** Whether this is the container of a ::before pseudo-element. */
 bool IsGeneratedContentContainerForBefore() const {
   return IsRootOfNativeAnonymousSubtree() &&
          mNodeInfo->NameAtom() == nsGkAtoms::mozgeneratedcontentbefore;
 }

 /** Whether this is the container of an ::after pseudo-element. */
 bool IsGeneratedContentContainerForAfter() const {
   return IsRootOfNativeAnonymousSubtree() &&
          mNodeInfo->NameAtom() == nsGkAtoms::mozgeneratedcontentafter;
 }

 /** Whether this is the container of a ::marker pseudo-element. */
 bool IsGeneratedContentContainerForMarker() const {
   return IsRootOfNativeAnonymousSubtree() &&
          mNodeInfo->NameAtom() == nsGkAtoms::mozgeneratedcontentmarker;
 }

 /** Whether this is the container of a ::backdrop pseudo-element. */
 bool IsGeneratedContentContainerForBackdrop() const {
   return IsRootOfNativeAnonymousSubtree() &&
          mNodeInfo->NameAtom() == nsGkAtoms::mozgeneratedcontentbackdrop;
 }

 /**
  * Returns true if |this| node is the closest common inclusive ancestor
  * (https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor) of the
  * start/end nodes of a Range in a Selection or a descendant of such a common
  * ancestor. This node is definitely not selected when |false| is returned,
  * but it may or may not be selected when |true| is returned.
  */
 bool IsMaybeSelected() const {
   return IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection() ||
          IsClosestCommonInclusiveAncestorForRangeInSelection();
 }

 /**
  * Return true if any part of (this, aStartOffset) .. (this, aEndOffset)
  * overlaps any nsRange in
  * GetClosestCommonInclusiveAncestorForRangeInSelection ranges (i.e.
  * where this is a descendant of a range's common inclusive ancestor node).
  * If a nsRange starts in (this, aEndOffset) or if it ends in
  * (this, aStartOffset) then it is non-overlapping and the result is false
  * for that nsRange.  Collapsed ranges always counts as non-overlapping.
  *
  * @param aStartOffset has to be less or equal to aEndOffset.
  * @param aCache A cache which contains all fully selected nodes for each
  *               selection. If present, this provides a fast path to check if
  *               a node is fully selected.
  */
 bool IsSelected(uint32_t aStartOffset, uint32_t aEndOffset,
                 mozilla::dom::SelectionNodeCache* aCache = nullptr) const;

#ifdef DEBUG
 void AssertIsRootElementSlow(bool) const;
#endif

 /** Returns whether we're the root element of our document. */
 bool IsRootElement() const {
   // This should be faster than pointer-chasing in the common cases, plus it
   // is also correct mid-unbind.
   const bool isRoot = !GetParent() && IsInUncomposedDoc() && IsElement();
#ifdef DEBUG
   AssertIsRootElementSlow(isRoot);
#endif
   return isRoot;
 }

 /**
  * Get the root element of the text editor associated with this node or the
  * root element of the text editor of the ancestor 'TextControlElement' if
  * this is in its native anonymous subtree.  I.e., this returns anonymous
  * `<div>` element of a `TextEditor`. Note that this can be used only for
  * getting root content of `<input>` or `<textarea>`.  I.e., this method
  * doesn't support HTML editors. Note that this may create a `TextEditor`
  * instance, and it means that the `TextEditor` may modify its native
  * anonymous subtree and may run selection listeners.
  */
 MOZ_CAN_RUN_SCRIPT mozilla::dom::Element* GetAnonymousRootElementOfTextEditor(
     mozilla::TextEditor** aTextEditor = nullptr);

 enum class IgnoreOwnIndependentSelection : bool { No, Yes };
 using AllowCrossShadowBoundary = mozilla::dom::AllowRangeCrossShadowBoundary;

 /**
  * Get the selection root for this node.
  * Note that if this node is not in an editor, the result comes from the
  * nsFrameSelection that is related to aPresShell, so the result might not be
  * the ancestor of this node.
  * Be aware that if this node and the computed selection limiter are not in
  * same subtree, this returns the root content of the closest subtree.
  *
  * @param aIgnoreOwnIndependentSelection
  *                    If "Yes", return selection root for selecting this node.
  *                    If "No", return independent selection root which is
  *                    in a native anonymous subtree hosted by this node.
  *                    For example, when this is a text control element,
  *                    return the document's selection root if "No" or return
  *                    the native anonymous <div> if "Yes".
  */
 MOZ_CAN_RUN_SCRIPT nsIContent* GetSelectionRootContent(
     mozilla::PresShell* aPresShell,
     IgnoreOwnIndependentSelection aIgnoreOwnIndependentSelection,
     AllowCrossShadowBoundary aAllowCrossShadowBoundary);

 [[nodiscard]] nsFrameSelection* GetFrameSelection() const;

 bool HasScheduledSelectionChangeEvent() {
   return HasFlag(NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT);
 }

 void SetHasScheduledSelectionChangeEvent() {
   SetFlags(NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT);
 }

 void ClearHasScheduledSelectionChangeEvent() {
   UnsetFlags(NODE_HAS_SCHEDULED_SELECTION_CHANGE_EVENT);
 }

 nsINodeList* ChildNodes();

 nsIContent* GetFirstChild() const { return mFirstChild; }

 nsIContent* GetLastChild() const;

 /**
  * Implementation is in Document.h, because it needs to cast from
  * Document* to nsINode*.
  */
 Document* GetOwnerDocument() const;

 // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
 MOZ_CAN_RUN_SCRIPT_BOUNDARY void Normalize();

 /**
  * Get the base URI for any relative URIs within this piece of
  * content. Generally, this is the document's base URI, but certain
  * content carries a local base for backward compatibility.
  *
  * @return the base URI.  May return null.
  */
 virtual nsIURI* GetBaseURI(bool aTryUseXHRDocBaseURI = false) const = 0;
 nsIURI* GetBaseURIObject() const;

 /**
  * Return true if the node may be apz aware. There are two cases. One is that
  * the node is apz aware (such as HTMLInputElement with number type). The
  * other is that the node has apz aware listeners. This is a non-virtual
  * function which calls IsNodeApzAwareInternal only when the MayBeApzAware is
  * set. We check the details in IsNodeApzAwareInternal which may be overriden
  * by child classes
  */
 bool IsNodeApzAware() const {
   return NodeMayBeApzAware() ? IsNodeApzAwareInternal() : false;
 }

 /**
  * Override this function and set the flag MayBeApzAware in case the node has
  * to let APZC be aware of it. It's used when the node may handle the apz
  * aware events and may do preventDefault to stop APZC to do default actions.
  *
  * For example, instead of scrolling page by APZ, we handle mouse wheel event
  * in HTMLInputElement with number type as increasing / decreasing its value.
  */
 virtual bool IsNodeApzAwareInternal() const;

 void GetTextContent(nsAString& aTextContent, mozilla::OOMReporter& aError) {
   GetTextContentInternal(aTextContent, aError);
 }
 MOZ_CAN_RUN_SCRIPT virtual void SetTextContent(
     const nsAString& aTextContent, nsIPrincipal* aSubjectPrincipal,
     mozilla::ErrorResult& aError) {
   SetTextContentInternal(aTextContent, aSubjectPrincipal, aError);
 }
 void SetTextContent(const nsAString& aTextContent,
                     mozilla::ErrorResult& aError) {
   SetTextContentInternal(aTextContent, nullptr, aError);
 }

 mozilla::dom::Element* QuerySelector(const nsACString& aSelector,
                                      mozilla::ErrorResult& aResult);
 already_AddRefed<nsINodeList> QuerySelectorAll(const nsACString& aSelector,
                                                mozilla::ErrorResult& aResult);

protected:
 // Document and ShadowRoot override this with its own (faster) version.
 // This should really only be called for elements and document fragments.
 mozilla::dom::Element* GetElementById(const nsAString& aId);

 void AppendChildToChildList(nsIContent* aKid);
 void InsertChildToChildList(nsIContent* aKid, nsIContent* aNextSibling);
 void DisconnectChild(nsIContent* aKid);

public:
 void LookupPrefix(const nsAString& aNamespace, nsAString& aResult);
 bool IsDefaultNamespace(const nsAString& aNamespaceURI) {
   nsAutoString defaultNamespace;
   LookupNamespaceURI(u""_ns, defaultNamespace);
   return aNamespaceURI.Equals(defaultNamespace);
 }
 void LookupNamespaceURI(const nsAString& aNamespacePrefix,
                         nsAString& aNamespaceURI);

 nsIContent* GetNextSibling() const { return mNextSibling; }
 nsIContent* GetPreviousSibling() const;

 /**
  * Return true if the node is being removed from the parent, it means that
  * the node still knows the container which it's disconnected from, but the
  * node has already been removed from the child node chain of the container.
  * I.e., Return true between a call of DisconnectChild of the parent and
  * a call of UnbindFromTree of the node.
  */
 bool IsBeingRemoved() const {
   return mParent && !mNextSibling && !mPreviousOrLastSibling;
 }

 /**
  * Get the next node in the pre-order tree traversal of the DOM.  If
  * aRoot is non-null, then it must be an ancestor of |this|
  * (possibly equal to |this|) and only nodes that are descendants of
  * aRoot, not including aRoot itself, will be returned.  Returns
  * null if there are no more nodes to traverse.
  */
 nsIContent* GetNextNode(const nsINode* aRoot = nullptr) const {
   return GetNextNodeImpl(aRoot, false);
 }

 /**
  * Get the next node in the pre-order tree traversal of the DOM but ignoring
  * the children of this node.  If aRoot is non-null, then it must be an
  * ancestor of |this| (possibly equal to |this|) and only nodes that are
  * descendants of aRoot, not including aRoot itself, will be returned.
  * Returns null if there are no more nodes to traverse.
  */
 nsIContent* GetNextNonChildNode(const nsINode* aRoot = nullptr) const {
   return GetNextNodeImpl(aRoot, true);
 }

 /**
  * Returns true if 'this' is either document or element or
  * document fragment and aOther is a descendant in the same
  * anonymous tree.
  */
 bool Contains(const nsINode* aOther) const;

 bool UnoptimizableCCNode() const;

 /**
  * Return true if the DevTools is observing the mutations in the owner
  * document.
  */
 [[nodiscard]] bool MaybeNeedsToNotifyDevToolsOfNodeRemovalsInOwnerDoc() const;

 /**
  * Return true when the DevTools should be notified of the removal of this
  * node.
  */
 [[nodiscard]] bool DevToolsShouldBeNotifiedOfThisRemoval() const;

 /**
  * Notify DevTools of the removals of all children of this node.
  * TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
  */
 MOZ_CAN_RUN_SCRIPT_BOUNDARY void NotifyDevToolsOfRemovalsOfChildren();

 void QueueDevtoolsAnonymousEvent(bool aIsRemove);

private:
 mozilla::dom::SVGUseElement* DoGetContainingSVGUseShadowHost() const;

 nsIContent* GetNextNodeImpl(const nsINode* aRoot,
                             const bool aSkipChildren) const {
#ifdef DEBUG
   if (aRoot) {
     // TODO: perhaps nsINode::IsInclusiveDescendantOf could be used instead.
     const nsINode* cur = this;
     for (; cur; cur = cur->GetParentNode())
       if (cur == aRoot) break;
     NS_ASSERTION(cur, "aRoot not an ancestor of |this|?");
   }
#endif
   if (!aSkipChildren) {
     nsIContent* kid = GetFirstChild();
     if (kid) {
       return kid;
     }
   }
   if (this == aRoot) {
     return nullptr;
   }
   const nsINode* cur = this;
   while (1) {
     nsIContent* next = cur->GetNextSibling();
     if (next) {
       return next;
     }
     nsINode* parent = cur->GetParentNode();
     if (parent == aRoot) {
       return nullptr;
     }
     cur = parent;
   }
   MOZ_ASSERT_UNREACHABLE("How did we get here?");
 }

public:
 /**
  * Get the previous nsIContent in the pre-order tree traversal of the DOM.  If
  * aRoot is non-null, then it must be an ancestor of |this|
  * (possibly equal to |this|) and only nsIContents that are descendants of
  * aRoot, including aRoot itself, will be returned.  Returns
  * null if there are no more nsIContents to traverse.
  */
 nsIContent* GetPrevNode(const nsINode* aRoot = nullptr) const {
#ifdef DEBUG
   if (aRoot) {
     // TODO: perhaps nsINode::IsInclusiveDescendantOf could be used instead.
     const nsINode* cur = this;
     for (; cur; cur = cur->GetParentNode())
       if (cur == aRoot) break;
     NS_ASSERTION(cur, "aRoot not an ancestor of |this|?");
   }
#endif

   if (this == aRoot) {
     return nullptr;
   }
   nsIContent* cur = this->GetParent();
   nsIContent* iter = this->GetPreviousSibling();
   while (iter) {
     cur = iter;
     iter = reinterpret_cast<nsINode*>(iter)->GetLastChild();
   }
   return cur;
 }

 /**
  * Boolean flags
  */
private:
 enum BooleanFlag {
   // Set if we're being used from -moz-element or observed via a mask,
   // clipPath, filter or use element.
   NodeHasDirectRenderingObservers,
   // Set if our parent chain (including this node itself) terminates
   // in a document
   IsInDocument,
   // Set if we're part of the composed doc.
   // https://dom.spec.whatwg.org/#connected
   IsConnected,
   // Set if mParent is an nsIContent
   ParentIsContent,
   // Set if this node is an Element
   NodeIsElement,
   // Set if the element has a non-empty id attribute. This can in rare
   // cases lie for nsXMLElement, such as when the node has been moved between
   // documents with different id mappings.
   ElementHasID,
   // Set if the element might have a class.
   ElementMayHaveClass,
   // Set if the element might have inline style.
   ElementMayHaveStyle,
   // Set if the element has a name attribute set.
   ElementHasName,
   // Set if the element has a part attribute set.
   ElementHasPart,
   // Set if the element might have a contenteditable attribute set.
   ElementMayHaveContentEditableAttr,
   // Set if the element has a contenteditable attribute whose value makes the
   // element editable.
   ElementHasContentEditableAttrTrueOrPlainTextOnly,
   // Set if the node is the closest common inclusive ancestor of the start/end
   // nodes of a Range that is in a Selection.
   NodeIsClosestCommonInclusiveAncestorForRangeInSelection,
   // Set if the node is a descendant of a node with the above bit set.
   NodeIsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection,
   // Set if CanSkipInCC check has been done for this subtree root.
   NodeIsCCMarkedRoot,
   // Maybe set if this node is in black subtree.
   NodeIsCCBlackTree,
   // Maybe set if the node is a root of a subtree
   // which needs to be kept in the purple buffer.
   NodeIsPurpleRoot,
   // Set if the element has some style states locked
   ElementHasLockedStyleStates,
   // Set if element has pointer locked
   ElementHasPointerLock,
   // Set if the node may have DOMMutationObserver attached to it.
   NodeMayHaveDOMMutationObserver,
   // Set if node is Content
   NodeIsContent,
   // Set if the node has animations or transitions
   ElementHasAnimations,
   // Set if node has a dir attribute with a valid value (ltr, rtl, or auto).
   // Note that we cannot compute this from the dir attribute event state
   // flags, because we can't use those to distinguish
   // <bdi dir="some-invalid-value"> and <bdi dir="auto">.
   NodeHasValidDirAttribute,
   // Set if a node in the node's parent chain has dir=auto and nothing
   // inbetween nor the node itself establishes its own direction.
   NodeAncestorHasDirAuto,
   // Set if the node or an ancestor is assigned to a dir=auto slot and
   // nothing between nor the node itself establishes its own direction.
   // Except for when the node assigned to the dir=auto slot establishes
   // its own direction, then the flag is still set.
   NodeAffectsDirAutoSlot,
   // Set if the node is handling a click.
   NodeHandlingClick,
   // Set if the element has a parser insertion mode other than "in body",
   // per the HTML5 "Parse state" section.
   ElementHasWeirdParserInsertionMode,
   // Parser sets this flag if it has notified about the node.
   ParserHasNotified,
   // Sets if the node is apz aware or we have apz aware listeners.
   MayBeApzAware,
   // Set if the element might have any kind of anonymous content children,
   // which would not be found through the element's children list.
   ElementMayHaveAnonymousChildren,
   // Set if element has CustomElementData.
   ElementHasCustomElementData,
   // Set if the element was created from prototype cache and
   // its l10n attributes haven't been changed.
   ElementCreatedFromPrototypeAndHasUnmodifiedL10n,
   // Guard value
   BooleanFlagCount
 };

 void SetBoolFlag(BooleanFlag name, bool value) {
   static_assert(BooleanFlagCount <= 8 * sizeof(mBoolFlags),
                 "Too many boolean flags");
   mBoolFlags = (mBoolFlags & ~(1U << name)) | (value << name);
 }

 void SetBoolFlag(BooleanFlag name) {
   static_assert(BooleanFlagCount <= 8 * sizeof(mBoolFlags),
                 "Too many boolean flags");
   mBoolFlags |= (1U << name);
 }

 void ClearBoolFlag(BooleanFlag name) {
   static_assert(BooleanFlagCount <= 8 * sizeof(mBoolFlags),
                 "Too many boolean flags");
   mBoolFlags &= ~(1U << name);
 }

 bool GetBoolFlag(BooleanFlag name) const {
   static_assert(BooleanFlagCount <= 8 * sizeof(mBoolFlags),
                 "Too many boolean flags");
   return mBoolFlags & (1U << name);
 }

public:
 bool HasDirectRenderingObservers() const {
   return GetBoolFlag(NodeHasDirectRenderingObservers);
 }
 void SetHasDirectRenderingObservers(bool aValue) {
   SetBoolFlag(NodeHasDirectRenderingObservers, aValue);
 }
 bool IsContent() const { return GetBoolFlag(NodeIsContent); }
 bool HasID() const { return GetBoolFlag(ElementHasID); }
 bool MayHaveClass() const { return GetBoolFlag(ElementMayHaveClass); }
 void SetMayHaveClass() { SetBoolFlag(ElementMayHaveClass); }
 bool MayHaveStyle() const { return GetBoolFlag(ElementMayHaveStyle); }
 bool HasName() const { return GetBoolFlag(ElementHasName); }
 bool HasPartAttribute() const { return GetBoolFlag(ElementHasPart); }
 bool MayHaveContentEditableAttr() const {
   return GetBoolFlag(ElementMayHaveContentEditableAttr);
 }
 /**
  * HasContentEditableAttrTrueOrPlainTextOnly() should not be called between
  * nsGenericHTMLElement::BeforeSetAttr and nsGenericHTMLElement::AfterSetAttr
  * because this is set and cleared by nsGenericHTMLElement::AfterSetAttr.
  */
 bool HasContentEditableAttrTrueOrPlainTextOnly() const {
   return GetBoolFlag(ElementHasContentEditableAttrTrueOrPlainTextOnly);
 }
 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor
  */
 bool IsClosestCommonInclusiveAncestorForRangeInSelection() const {
   return GetBoolFlag(NodeIsClosestCommonInclusiveAncestorForRangeInSelection);
 }
 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor
  */
 void SetClosestCommonInclusiveAncestorForRangeInSelection() {
   SetBoolFlag(NodeIsClosestCommonInclusiveAncestorForRangeInSelection);
 }
 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor
  */
 void ClearClosestCommonInclusiveAncestorForRangeInSelection() {
   ClearBoolFlag(NodeIsClosestCommonInclusiveAncestorForRangeInSelection);
 }
 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor
  */
 bool IsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection() const {
   return GetBoolFlag(
       NodeIsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection);
 }
 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor
  */
 void SetDescendantOfClosestCommonInclusiveAncestorForRangeInSelection() {
   SetBoolFlag(
       NodeIsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection);
 }
 /**
  * https://dom.spec.whatwg.org/#concept-tree-inclusive-ancestor
  */
 void ClearDescendantOfClosestCommonInclusiveAncestorForRangeInSelection() {
   ClearBoolFlag(
       NodeIsDescendantOfClosestCommonInclusiveAncestorForRangeInSelection);
 }

 void SetCCMarkedRoot(bool aValue) { SetBoolFlag(NodeIsCCMarkedRoot, aValue); }
 bool CCMarkedRoot() const { return GetBoolFlag(NodeIsCCMarkedRoot); }
 void SetInCCBlackTree(bool aValue) { SetBoolFlag(NodeIsCCBlackTree, aValue); }
 bool InCCBlackTree() const { return GetBoolFlag(NodeIsCCBlackTree); }
 void SetIsPurpleRoot(bool aValue) { SetBoolFlag(NodeIsPurpleRoot, aValue); }
 bool IsPurpleRoot() const { return GetBoolFlag(NodeIsPurpleRoot); }
 bool MayHaveDOMMutationObserver() {
   return GetBoolFlag(NodeMayHaveDOMMutationObserver);
 }
 void SetMayHaveDOMMutationObserver() {
   SetBoolFlag(NodeMayHaveDOMMutationObserver, true);
 }
 bool HasListenerManager() { return HasFlag(NODE_HAS_LISTENERMANAGER); }
 bool HasPointerLock() const { return GetBoolFlag(ElementHasPointerLock); }
 void SetPointerLock() { SetBoolFlag(ElementHasPointerLock); }
 void ClearPointerLock() { ClearBoolFlag(ElementHasPointerLock); }
 bool MayHaveAnimations() const { return GetBoolFlag(ElementHasAnimations); }
 void SetMayHaveAnimations() { SetBoolFlag(ElementHasAnimations); }
 void ClearMayHaveAnimations() { ClearBoolFlag(ElementHasAnimations); }
 void SetHasValidDir() { SetBoolFlag(NodeHasValidDirAttribute); }
 void ClearHasValidDir() { ClearBoolFlag(NodeHasValidDirAttribute); }
 bool HasValidDir() const { return GetBoolFlag(NodeHasValidDirAttribute); }
 void SetAncestorHasDirAuto() { SetBoolFlag(NodeAncestorHasDirAuto); }
 void ClearAncestorHasDirAuto() { ClearBoolFlag(NodeAncestorHasDirAuto); }
 bool AncestorHasDirAuto() const {
   return GetBoolFlag(NodeAncestorHasDirAuto);
 }
 void SetAffectsDirAutoSlot() { SetBoolFlag(NodeAffectsDirAutoSlot); }
 void ClearAffectsDirAutoSlot() { ClearBoolFlag(NodeAffectsDirAutoSlot); }

 // Set if the node or an ancestor is assigned to a dir=auto slot.
 bool AffectsDirAutoSlot() const {
   return GetBoolFlag(NodeAffectsDirAutoSlot);
 }

 // Implemented in nsIContentInlines.h.
 inline bool NodeOrAncestorHasDirAuto() const;

 void SetParserHasNotified() { SetBoolFlag(ParserHasNotified); };
 bool HasParserNotified() { return GetBoolFlag(ParserHasNotified); }

 void SetMayBeApzAware() { SetBoolFlag(MayBeApzAware); }
 bool NodeMayBeApzAware() const { return GetBoolFlag(MayBeApzAware); }

 void SetMayHaveAnonymousChildren() {
   SetBoolFlag(ElementMayHaveAnonymousChildren);
 }
 bool MayHaveAnonymousChildren() const {
   return GetBoolFlag(ElementMayHaveAnonymousChildren);
 }

 void SetHasCustomElementData() { SetBoolFlag(ElementHasCustomElementData); }
 bool HasCustomElementData() const {
   return GetBoolFlag(ElementHasCustomElementData);
 }

 void SetElementCreatedFromPrototypeAndHasUnmodifiedL10n() {
   SetBoolFlag(ElementCreatedFromPrototypeAndHasUnmodifiedL10n);
 }
 bool HasElementCreatedFromPrototypeAndHasUnmodifiedL10n() {
   return GetBoolFlag(ElementCreatedFromPrototypeAndHasUnmodifiedL10n);
 }
 void ClearElementCreatedFromPrototypeAndHasUnmodifiedL10n() {
   ClearBoolFlag(ElementCreatedFromPrototypeAndHasUnmodifiedL10n);
 }

 inline mozilla::dom::ShadowRoot* GetShadowRoot() const;

 // Return the shadow root of the node if it is a shadow host and
 // it meets the requirements for being a shadow host of a selection.
 // For example, <details>, <video> and <use> elements are not valid
 // shadow host for selection.
 mozilla::dom::ShadowRoot* GetShadowRootForSelection() const;

protected:
 void SetParentIsContent(bool aValue) { SetBoolFlag(ParentIsContent, aValue); }
 void SetIsInDocument() { SetBoolFlag(IsInDocument); }
 void ClearInDocument() { ClearBoolFlag(IsInDocument); }
 void SetIsConnected(bool aConnected) { SetBoolFlag(IsConnected, aConnected); }
 void SetNodeIsContent() { SetBoolFlag(NodeIsContent); }
 void SetIsElement() { SetBoolFlag(NodeIsElement); }
 void SetHasID() { SetBoolFlag(ElementHasID); }
 void ClearHasID() { ClearBoolFlag(ElementHasID); }
 void SetMayHaveStyle() { SetBoolFlag(ElementMayHaveStyle); }
 void SetHasName() { SetBoolFlag(ElementHasName); }
 void ClearHasName() { ClearBoolFlag(ElementHasName); }
 void SetHasPartAttribute(bool aPart) { SetBoolFlag(ElementHasPart, aPart); }
 void SetMayHaveContentEditableAttr() {
   SetBoolFlag(ElementMayHaveContentEditableAttr);
 }
 void ClearMayHaveContentEditableAttr() {
   ClearBoolFlag(ElementMayHaveContentEditableAttr);
 }
 void SetHasContentEditableAttrTrueOrPlainTextOnly() {
   SetBoolFlag(ElementHasContentEditableAttrTrueOrPlainTextOnly);
 }
 void ClearHasContentEditableAttrTrueOrPlainTextOnly() {
   ClearBoolFlag(ElementHasContentEditableAttrTrueOrPlainTextOnly);
 }
 void SetHasLockedStyleStates() { SetBoolFlag(ElementHasLockedStyleStates); }
 void ClearHasLockedStyleStates() {
   ClearBoolFlag(ElementHasLockedStyleStates);
 }
 bool HasLockedStyleStates() const {
   return GetBoolFlag(ElementHasLockedStyleStates);
 }
 void SetHasWeirdParserInsertionMode() {
   SetBoolFlag(ElementHasWeirdParserInsertionMode);
 }
 bool HasWeirdParserInsertionMode() const {
   return GetBoolFlag(ElementHasWeirdParserInsertionMode);
 }
 bool HandlingClick() const { return GetBoolFlag(NodeHandlingClick); }
 void SetHandlingClick() { SetBoolFlag(NodeHandlingClick); }
 void ClearHandlingClick() { ClearBoolFlag(NodeHandlingClick); }

 void SetSubtreeRootPointer(nsINode* aSubtreeRoot) {
   NS_ASSERTION(aSubtreeRoot, "aSubtreeRoot can never be null!");
   NS_ASSERTION(!(IsContent() && IsInUncomposedDoc()) && !IsInShadowTree(),
                "Shouldn't be here!");
   mSubtreeRoot = aSubtreeRoot;
 }

 void ClearSubtreeRootPointer() { mSubtreeRoot = nullptr; }

public:
 // Makes nsINode object keep aObject alive. If a callback is provided, it's
 // called before deleting the node.
 void BindObject(nsISupports* aObject, UnbindCallback = nullptr);
 // After calling UnbindObject nsINode, object doesn't keep aObject alive
 // anymore.
 void UnbindObject(nsISupports* aObject);

 void GenerateXPath(nsAString& aResult);

 already_AddRefed<mozilla::dom::AccessibleNode> GetAccessibleNode();

 /**
  * Returns the length of this node, as specified at
  * <http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-node-length>
  */
 uint32_t Length() const;

 void GetNodeName(mozilla::dom::DOMString& aNodeName) {
   const nsString& nodeName = NodeName();
   aNodeName.SetKnownLiveString(nodeName);
 }
 [[nodiscard]] nsresult GetBaseURI(nsAString& aBaseURI) const;
 // Return the base URI for the document.
 // The returned value may differ if the document is loaded via XHR, and
 // when accessed from chrome privileged script and
 // from content privileged script for compatibility.
 void GetBaseURIFromJS(nsAString& aBaseURI, CallerType aCallerType,
                       ErrorResult& aRv) const;
 bool HasChildNodes() const { return HasChildren(); }

 uint16_t CompareDocumentPosition(const nsINode& aOther) const;
 void GetNodeValue(nsAString& aNodeValue) { GetNodeValueInternal(aNodeValue); }
 MOZ_CAN_RUN_SCRIPT virtual void SetNodeValue(const nsAString& aNodeValue,
                                              mozilla::ErrorResult& aError) {
   SetNodeValueInternal(aNodeValue, aError);
 }
 virtual void GetNodeValueInternal(nsAString& aNodeValue);
 virtual void SetNodeValueInternal(
     const nsAString& aNodeValue, mozilla::ErrorResult& aError,
     MutationEffectOnScript aMutationEffectOnScript =
         MutationEffectOnScript::DropTrustWorthiness) {
   // The DOM spec says that when nodeValue is defined to be null "setting it
   // has no effect", so we don't throw an exception.
 }
 void EnsurePreInsertionValidity(nsINode& aNewChild, nsINode* aRefChild,
                                 mozilla::ErrorResult& aError);
 nsINode* InsertBefore(nsINode& aNode, nsINode* aChild,
                       mozilla::ErrorResult& aError) {
   return InsertBeforeInternal(
       aNode, aChild, MutationEffectOnScript::DropTrustWorthiness, aError);
 }
 nsINode* InsertBeforeInternal(nsINode& aNode, nsINode* aChild,
                               MutationEffectOnScript aMutationEffectOnScript,
                               mozilla::ErrorResult& aError) {
   return ReplaceOrInsertBefore(false, &aNode, aChild, aMutationEffectOnScript,
                                aError);
 }

 /**
  * See <https://dom.spec.whatwg.org/#dom-node-appendchild>.
  */
 nsINode* AppendChild(nsINode& aNode, mozilla::ErrorResult& aError) {
   return AppendChildInternal(
       aNode, MutationEffectOnScript::DropTrustWorthiness, aError);
 }
 nsINode* AppendChildInternal(nsINode& aNode,
                              MutationEffectOnScript aMutationEffectOnScript,
                              mozilla::ErrorResult& aError) {
   return InsertBeforeInternal(aNode, nullptr, aMutationEffectOnScript,
                               aError);
 }

 nsINode* ReplaceChild(nsINode& aNode, nsINode& aChild,
                       mozilla::ErrorResult& aError) {
   return ReplaceChildInternal(
       aNode, aChild, MutationEffectOnScript::DropTrustWorthiness, aError);
 }
 nsINode* ReplaceChildInternal(nsINode& aNode, nsINode& aChild,
                               MutationEffectOnScript aMutationEffectOnScript,
                               mozilla::ErrorResult& aError) {
   return ReplaceOrInsertBefore(true, &aNode, &aChild, aMutationEffectOnScript,
                                aError);
 }

 nsINode* RemoveChild(nsINode& aChild, mozilla::ErrorResult& aError) {
   return RemoveChildInternal(
       aChild, MutationEffectOnScript::DropTrustWorthiness, aError);
 }
 // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
 MOZ_CAN_RUN_SCRIPT_BOUNDARY nsINode* RemoveChildInternal(
     nsINode& aChild, MutationEffectOnScript aMutationEffectOnScript,
     mozilla::ErrorResult& aError);
 already_AddRefed<nsINode> CloneNode(bool aDeep, mozilla::ErrorResult& aError);
 bool IsSameNode(nsINode* aNode);
 bool IsEqualNode(nsINode* aNode);
 void GetNamespaceURI(nsAString& aNamespaceURI) const {
   mNodeInfo->GetNamespaceURI(aNamespaceURI);
 }
#ifdef MOZILLA_INTERNAL_API
 void GetPrefix(nsAString& aPrefix) { mNodeInfo->GetPrefix(aPrefix); }
#endif
 void GetLocalName(mozilla::dom::DOMString& aLocalName) const {
   const nsString& localName = LocalName();
   aLocalName.SetKnownLiveString(localName);
 }

 nsDOMAttributeMap* GetAttributes();

 // Helper method to remove this node from its parent. This is not exposed
 // through WebIDL.
 // Only call this if the node has a parent node.
 nsresult RemoveFromParent() {
   nsINode* parent = GetParentNode();
   mozilla::ErrorResult rv;
   parent->RemoveChildInternal(
       *this, MutationEffectOnScript::DropTrustWorthiness, rv);
   return rv.StealNSResult();
 }

 // ChildNode methods
 inline mozilla::dom::Element* GetPreviousElementSibling() const;
 inline mozilla::dom::Element* GetNextElementSibling() const;

 MOZ_CAN_RUN_SCRIPT void Before(const Sequence<OwningNodeOrString>& aNodes,
                                ErrorResult& aRv);
 MOZ_CAN_RUN_SCRIPT void After(const Sequence<OwningNodeOrString>& aNodes,
                               ErrorResult& aRv);
 MOZ_CAN_RUN_SCRIPT void ReplaceWith(
     const Sequence<OwningNodeOrString>& aNodes, ErrorResult& aRv);
 /**
  * Remove this node from its parent, if any.
  */
 void Remove();

 // ParentNode methods
 mozilla::dom::Element* GetFirstElementChild() const;
 mozilla::dom::Element* GetLastElementChild() const;

 already_AddRefed<nsIHTMLCollection> GetElementsByAttribute(
     const nsAString& aAttribute, const nsAString& aValue);
 already_AddRefed<nsIHTMLCollection> GetElementsByAttributeNS(
     const nsAString& aNamespaceURI, const nsAString& aAttribute,
     const nsAString& aValue, ErrorResult& aRv);

 MOZ_CAN_RUN_SCRIPT void Prepend(const Sequence<OwningNodeOrString>& aNodes,
                                 ErrorResult& aRv);
 MOZ_CAN_RUN_SCRIPT void Append(const Sequence<OwningNodeOrString>& aNodes,
                                ErrorResult& aRv);
 MOZ_CAN_RUN_SCRIPT void ReplaceChildren(
     const Sequence<OwningNodeOrString>& aNodes, ErrorResult& aRv);
 MOZ_CAN_RUN_SCRIPT void ReplaceChildren(
     nsINode* aNode, ErrorResult& aRv,
     MutationEffectOnScript aMutationEffectOnScript =
         MutationEffectOnScript::DropTrustWorthiness);

 MOZ_CAN_RUN_SCRIPT void MoveBefore(nsINode& aNode, nsINode* aChild,
                                    ErrorResult& aRv);

 void GetBoxQuads(const BoxQuadOptions& aOptions,
                  nsTArray<RefPtr<DOMQuad>>& aResult, CallerType aCallerType,
                  ErrorResult& aRv);

 void GetBoxQuadsFromWindowOrigin(const BoxQuadOptions& aOptions,
                                  nsTArray<RefPtr<DOMQuad>>& aResult,
                                  ErrorResult& aRv);

 already_AddRefed<DOMQuad> ConvertQuadFromNode(
     DOMQuad& aQuad, const TextOrElementOrDocument& aFrom,
     const ConvertCoordinateOptions& aOptions, CallerType aCallerType,
     ErrorResult& aRv);
 already_AddRefed<DOMQuad> ConvertRectFromNode(
     DOMRectReadOnly& aRect, const TextOrElementOrDocument& aFrom,
     const ConvertCoordinateOptions& aOptions, CallerType aCallerType,
     ErrorResult& aRv);
 already_AddRefed<DOMPoint> ConvertPointFromNode(
     const DOMPointInit& aPoint, const TextOrElementOrDocument& aFrom,
     const ConvertCoordinateOptions& aOptions, CallerType aCallerType,
     ErrorResult& aRv);

 /**
  * See nsSlots::mClosestCommonInclusiveAncestorRanges.
  */
 const mozilla::LinkedList<mozilla::dom::AbstractRange>*
 GetExistingClosestCommonInclusiveAncestorRanges() const {
   if (!HasSlots()) {
     return nullptr;
   }
   return GetExistingSlots()->mClosestCommonInclusiveAncestorRanges.get();
 }

 /**
  * See nsSlots::mClosestCommonInclusiveAncestorRanges.
  */
 mozilla::LinkedList<mozilla::dom::AbstractRange>*
 GetExistingClosestCommonInclusiveAncestorRanges() {
   if (!HasSlots()) {
     return nullptr;
   }
   return GetExistingSlots()->mClosestCommonInclusiveAncestorRanges.get();
 }

 /**
  * See nsSlots::mClosestCommonInclusiveAncestorRanges.
  */
 mozilla::UniquePtr<mozilla::LinkedList<mozilla::dom::AbstractRange>>&
 GetClosestCommonInclusiveAncestorRangesPtr() {
   return Slots()->mClosestCommonInclusiveAncestorRanges;
 }

 nsIWeakReference* GetExistingWeakReference() {
   return HasSlots() ? GetExistingSlots()->mWeakReference : nullptr;
 }

 void QueueAncestorRevealingAlgorithm();

 MOZ_CAN_RUN_SCRIPT void AncestorRevealingAlgorithm(ErrorResult& aRv);

protected:
 // Override this function to create a custom slots class.
 // Must not return null.
 virtual nsINode::nsSlots* CreateSlots();

 bool HasSlots() const { return mSlots != nullptr; }

 nsSlots* GetExistingSlots() const { return mSlots; }

 nsSlots* Slots() {
   if (!HasSlots()) {
     mSlots = CreateSlots();
     MOZ_ASSERT(mSlots);
   }
   return GetExistingSlots();
 }

 /**
  * Invalidate cached child array inside mChildNodes
  * of type nsParentNodeChildContentList.
  */
 void InvalidateChildNodes();

 virtual void GetTextContentInternal(nsAString& aTextContent,
                                     mozilla::OOMReporter& aError);
 virtual void SetTextContentInternal(
     const nsAString& aTextContent, nsIPrincipal* aSubjectPrincipal,
     mozilla::ErrorResult& aError,
     MutationEffectOnScript aMutationEffectOnScript =
         MutationEffectOnScript::DropTrustWorthiness) {}

 void EnsurePreInsertionValidity1(mozilla::ErrorResult& aError);
 void EnsurePreInsertionValidity2(bool aReplace, nsINode& aNewChild,
                                  nsINode* aRefChild,
                                  mozilla::ErrorResult& aError);
 // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
 MOZ_CAN_RUN_SCRIPT_BOUNDARY nsINode* ReplaceOrInsertBefore(
     bool aReplace, nsINode* aNewChild, nsINode* aRefChild,
     MutationEffectOnScript aMutationEffectOnScript,
     mozilla::ErrorResult& aError);

 /**
  * Returns the Element that should be used for resolving namespaces
  * on this node (ie the ownerElement for attributes, the documentElement for
  * documents, the node itself for elements and for other nodes the parentNode
  * if it is an element).
  */
 virtual mozilla::dom::Element* GetNameSpaceElement() = 0;

 /**
  * Parse the given selector string into a servo SelectorList.
  *
  * Never returns null if aRv is not failing.
  *
  * Note that the selector list returned here is owned by the owner doc's
  * selector cache.
  */
 const mozilla::StyleSelectorList* ParseSelectorList(
     const nsACString& aSelectorString, mozilla::ErrorResult&);

public:
 /* Event stuff that documents and elements share.

    Note that we include DOCUMENT_ONLY_EVENT events here so that we
    can forward all the document stuff to this implementation.
 */
#define EVENT(name_, id_, type_, struct_)                         \
 mozilla::dom::EventHandlerNonNull* GetOn##name_() {             \
   return GetEventHandler(nsGkAtoms::on##name_);                 \
 }                                                               \
 void SetOn##name_(mozilla::dom::EventHandlerNonNull* handler) { \
   SetEventHandler(nsGkAtoms::on##name_, handler);               \
 }
#define TOUCH_EVENT EVENT
#define DOCUMENT_ONLY_EVENT EVENT
#include "mozilla/EventNameList.h"
#undef DOCUMENT_ONLY_EVENT
#undef TOUCH_EVENT
#undef EVENT

 NodeSelectorFlags GetSelectorFlags() const {
   return static_cast<NodeSelectorFlags>(mSelectorFlags.Get());
 }

protected:
 static bool Traverse(nsINode* tmp, nsCycleCollectionTraversalCallback& cb);
 static void Unlink(nsINode* tmp);

 RefPtr<mozilla::dom::NodeInfo> mNodeInfo;

 // mParent is an owning ref most of the time, except for the case of document
 // nodes, so it cannot be represented by nsCOMPtr, so mark is as
 // MOZ_OWNING_REF.
 nsINode* MOZ_OWNING_REF mParent;

private:
#ifndef BOOL_FLAGS_ON_WRAPPER_CACHE
 // Boolean flags.
 uint32_t mBoolFlags;
#endif

 mozilla::RustCell<uint32_t> mSelectorFlags{0};

 uint32_t mChildCount;

protected:
 // mNextSibling and mFirstChild are strong references while
 // mPreviousOrLastSibling is a weak ref. |mFirstChild->mPreviousOrLastSibling|
 // points to the last child node.
 nsCOMPtr<nsIContent> mFirstChild;
 nsCOMPtr<nsIContent> mNextSibling;
 nsIContent* MOZ_NON_OWNING_REF mPreviousOrLastSibling;

 union {
   // Pointer to our primary frame.  Might be null.
   nsIFrame* mPrimaryFrame;

   // Pointer to the root of our subtree.  Might be null.
   // This reference is non-owning and safe, since it either points to the
   // object itself, or is reset by ClearSubtreeRootPointer.
   nsINode* MOZ_NON_OWNING_REF mSubtreeRoot;
 };

 // Storage for more members that are usually not needed; allocated lazily.
 nsSlots* mSlots;
};

NON_VIRTUAL_ADDREF_RELEASE(nsINode)

template <>
struct fmt::formatter<nsINode> : ostream_formatter {};

inline nsINode* mozilla::dom::EventTarget::GetAsNode() {
 return IsNode() ? AsNode() : nullptr;
}

inline const nsINode* mozilla::dom::EventTarget::GetAsNode() const {
 return const_cast<mozilla::dom::EventTarget*>(this)->GetAsNode();
}

inline nsINode* mozilla::dom::EventTarget::AsNode() {
 MOZ_DIAGNOSTIC_ASSERT(IsNode());
 return static_cast<nsINode*>(this);
}

inline const nsINode* mozilla::dom::EventTarget::AsNode() const {
 MOZ_DIAGNOSTIC_ASSERT(IsNode());
 return static_cast<const nsINode*>(this);
}

// Useful inline function for getting a node given an nsIContent and a Document.
// Returns the first argument cast to nsINode if it is non-null, otherwise
// returns the second (which may be null).  We use type variables instead of
// nsIContent* and Document* because the actual types must be
// known for the cast to work.
template <class C, class D>
inline nsINode* NODE_FROM(C& aContent, D& aDocument) {
 if (aContent) return static_cast<nsINode*>(aContent);
 return static_cast<nsINode*>(aDocument);
}

inline nsISupports* ToSupports(nsINode* aPointer) { return aPointer; }

// Some checks are faster to do on nsIContent or Element than on
// nsINode, so spit out FromNode versions taking those types too.
#define NS_IMPL_FROMNODE_GENERIC(_class, _check, _const)                 \
 template <typename T>                                                  \
 static auto FromNode(_const T& aNode)                                  \
     -> decltype(static_cast<_const _class*>(&aNode)) {                 \
   return aNode._check ? static_cast<_const _class*>(&aNode) : nullptr; \
 }                                                                      \
 template <typename T>                                                  \
 static _const _class* FromNode(_const T* aNode) {                      \
   return FromNode(*aNode);                                             \
 }                                                                      \
 template <typename T>                                                  \
 static _const _class* FromNodeOrNull(_const T* aNode) {                \
   return aNode ? FromNode(*aNode) : nullptr;                           \
 }                                                                      \
 template <typename T>                                                  \
 static auto FromEventTarget(_const T& aEventTarget)                    \
     -> decltype(static_cast<_const _class*>(&aEventTarget)) {          \
   return aEventTarget.IsNode() && aEventTarget.AsNode()->_check        \
              ? static_cast<_const _class*>(&aEventTarget)              \
              : nullptr;                                                \
 }                                                                      \
 template <typename T>                                                  \
 static _const _class* FromEventTarget(_const T* aEventTarget) {        \
   return FromEventTarget(*aEventTarget);                               \
 }                                                                      \
 template <typename T>                                                  \
 static _const _class* FromEventTargetOrNull(_const T* aEventTarget) {  \
   return aEventTarget ? FromEventTarget(*aEventTarget) : nullptr;      \
 }

#define NS_IMPL_FROMNODE_HELPER(_class, _check)                                \
 NS_IMPL_FROMNODE_GENERIC(_class, _check, )                                   \
 NS_IMPL_FROMNODE_GENERIC(_class, _check, const)                              \
                                                                              \
 template <typename T>                                                        \
 static _class* FromNode(T&& aNode) {                                         \
   /* We need the double-cast in case aNode is a smartptr.  Those */          \
   /* can cast to superclasses of the type they're templated on, */           \
   /* but not directly to subclasses.  */                                     \
   return aNode->_check ? static_cast<_class*>(static_cast<nsINode*>(aNode))  \
                        : nullptr;                                            \
 }                                                                            \
 template <typename T>                                                        \
 static _class* FromNodeOrNull(T&& aNode) {                                   \
   return aNode ? FromNode(aNode) : nullptr;                                  \
 }                                                                            \
 template <typename T>                                                        \
 static _class* FromEventTarget(T&& aEventTarget) {                           \
   /* We need the double-cast in case aEventTarget is a smartptr.  Those */   \
   /* can cast to superclasses of the type they're templated on, */           \
   /* but not directly to subclasses.  */                                     \
   return aEventTarget->IsNode() && aEventTarget->AsNode()->_check            \
              ? static_cast<_class*>(static_cast<EventTarget*>(aEventTarget)) \
              : nullptr;                                                      \
 }                                                                            \
 template <typename T>                                                        \
 static _class* FromEventTargetOrNull(T&& aEventTarget) {                     \
   return aEventTarget ? FromEventTarget(aEventTarget) : nullptr;             \
 }

#define NS_IMPL_FROMNODE(_class, _nsid) \
 NS_IMPL_FROMNODE_HELPER(_class, IsInNamespace(_nsid))

#define NS_IMPL_FROMNODE_WITH_TAG(_class, _nsid, _tag) \
 NS_IMPL_FROMNODE_HELPER(_class, NodeInfo()->Equals(nsGkAtoms::_tag, _nsid))

#define NS_IMPL_FROMNODE_HTML_WITH_TAG(_class, _tag) \
 NS_IMPL_FROMNODE_WITH_TAG(_class, kNameSpaceID_XHTML, _tag)

#endif /* nsINode_h___ */