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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef mozilla_a11y_RemoteAccessible_h
#define mozilla_a11y_RemoteAccessible_h
#include "mozilla/a11y/Accessible.h"
#include "mozilla/a11y/CacheConstants.h"
#include "mozilla/a11y/HyperTextAccessibleBase.h"
#include "mozilla/a11y/Role.h"
#include "AccAttributes.h"
#include "nsIAccessibleText.h"
#include "nsIAccessibleTypes.h"
#include "nsTArray.h"
#include "nsRect.h"
#include "LocalAccessible.h"
namespace mozilla {
namespace a11y {
class Attribute;
class DocAccessibleParent;
class RemoteAccessible;
enum class RelationType;
* The class for an accessibility tree node that originated in the parent
* process.
class RemoteAccessible : public Accessible, public HyperTextAccessibleBase {
virtual ~RemoteAccessible() {
virtual bool IsRemote() const override { return true; }
void AddChildAt(uint32_t aIdx, RemoteAccessible* aChild) {
mChildren.InsertElementAt(aIdx, aChild);
if (IsHyperText()) {
virtual uint32_t ChildCount() const override { return mChildren.Length(); }
RemoteAccessible* RemoteChildAt(uint32_t aIdx) const {
return mChildren.SafeElementAt(aIdx);
RemoteAccessible* RemoteFirstChild() const {
return mChildren.Length() ? mChildren[0] : nullptr;
RemoteAccessible* RemoteLastChild() const {
return mChildren.Length() ? mChildren[mChildren.Length() - 1] : nullptr;
RemoteAccessible* RemotePrevSibling() const {
if (IsDoc()) {
// The normal code path doesn't work for documents because the parent
// might be a local OuterDoc, but IndexInParent() will return 1.
// A document is always a single child of an OuterDoc anyway.
return nullptr;
int32_t idx = IndexInParent();
if (idx == -1) {
return nullptr; // No parent.
return idx > 0 ? RemoteParent()->mChildren[idx - 1] : nullptr;
RemoteAccessible* RemoteNextSibling() const {
if (IsDoc()) {
// The normal code path doesn't work for documents because the parent
// might be a local OuterDoc, but IndexInParent() will return 1.
// A document is always a single child of an OuterDoc anyway.
return nullptr;
int32_t idx = IndexInParent();
if (idx == -1) {
return nullptr; // No parent.
MOZ_ASSERT(idx >= 0);
size_t newIdx = idx + 1;
return newIdx < RemoteParent()->mChildren.Length()
? RemoteParent()->mChildren[newIdx]
: nullptr;
// Accessible hierarchy method overrides
virtual Accessible* Parent() const override { return RemoteParent(); }
virtual Accessible* ChildAt(uint32_t aIndex) const override {
return RemoteChildAt(aIndex);
virtual Accessible* NextSibling() const override {
return RemoteNextSibling();
virtual Accessible* PrevSibling() const override {
return RemotePrevSibling();
// XXX evaluate if this is fast enough.
virtual int32_t IndexInParent() const override {
RemoteAccessible* parent = RemoteParent();
if (!parent) {
return -1;
return parent->mChildren.IndexOf(
static_cast<const RemoteAccessible*>(this));
virtual uint32_t EmbeddedChildCount() override;
virtual int32_t IndexOfEmbeddedChild(Accessible* aChild) override;
virtual Accessible* EmbeddedChildAt(uint32_t aChildIdx) override;
void Shutdown();
void SetChildDoc(DocAccessibleParent* aChildDoc);
void ClearChildDoc(DocAccessibleParent* aChildDoc);
* Remove The given child.
void RemoveChild(RemoteAccessible* aChild) {
if (IsHyperText()) {
* Return the proxy for the parent of the wrapped accessible.
RemoteAccessible* RemoteParent() const;
LocalAccessible* OuterDocOfRemoteBrowser() const;
* Get the role of the accessible we're proxying.
virtual role Role() const override { return mRole; }
* Return true if this is an embedded object.
bool IsEmbeddedObject() const { return !IsText(); }
virtual bool IsLink() const override {
if (IsHTMLLink()) {
// XXX: HTML links always return true for IsLink.
return true;
if (IsText()) {
return false;
if (Accessible* parent = Parent()) {
return parent->IsHyperText();
return false;
virtual bool HasNumericValue() const override {
// XXX: We combine the aria and native "has numeric value" field
// when we serialize the local accessible into eNumericValue.
return HasGenericType(eNumericValue);
// Methods that potentially access a cache.
virtual ENameValueFlag Name(nsString& aName) const override;
virtual void Description(nsString& aDescription) const override;
virtual void Value(nsString& aValue) const override;
virtual double CurValue() const override;
virtual double MinValue() const override;
virtual double MaxValue() const override;
virtual double Step() const override;
virtual bool SetCurValue(double aValue) override;
virtual Accessible* ChildAtPoint(
int32_t aX, int32_t aY,
LocalAccessible::EWhichChildAtPoint aWhichChild) override;
virtual LayoutDeviceIntRect Bounds() const override;
virtual nsRect BoundsInAppUnits() const override;
virtual Relation RelationByType(RelationType aType) const override;
virtual uint64_t State() override;
virtual already_AddRefed<AccAttributes> Attributes() override;
virtual nsAtom* TagName() const override;
virtual already_AddRefed<nsAtom> InputType() const override;
virtual already_AddRefed<nsAtom> DisplayStyle() const override;
virtual float Opacity() const override;
virtual void LiveRegionAttributes(nsAString* aLive, nsAString* aRelevant,
Maybe<bool>* aAtomic,
nsAString* aBusy) const override;
virtual Maybe<bool> ARIASelected() const override;
virtual uint8_t ActionCount() const override;
virtual void ActionNameAt(uint8_t aIndex, nsAString& aName) override;
virtual bool DoAction(uint8_t aIndex) const override;
virtual KeyBinding AccessKey() const override;
virtual void SelectionRanges(nsTArray<TextRange>* aRanges) const override;
MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual bool RemoveFromSelection(
int32_t aSelectionNum) override;
virtual Maybe<int32_t> GetIntARIAAttr(nsAtom* aAttrName) const override;
virtual void Language(nsAString& aLocale) override;
// EditableTextAccessible
MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void ReplaceText(
const nsAString& aText) override;
MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void InsertText(
const nsAString& aText, int32_t aPosition) override;
MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void CopyText(int32_t aStartPos,
int32_t aEndPos) override;
MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void CutText(int32_t aStartPos,
int32_t aEndPos) override;
MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void DeleteText(int32_t aStartPos,
int32_t aEndPos) override;
MOZ_CAN_RUN_SCRIPT virtual void PasteText(int32_t aPosition) override;
// SelectAccessible
virtual void SelectedItems(nsTArray<Accessible*>* aItems) override;
virtual uint32_t SelectedItemCount() override;
virtual Accessible* GetSelectedItem(uint32_t aIndex) override;
virtual bool IsItemSelected(uint32_t aIndex) override;
virtual bool AddItemToSelection(uint32_t aIndex) override;
virtual bool RemoveItemFromSelection(uint32_t aIndex) override;
virtual bool SelectAll() override;
virtual bool UnselectAll() override;
virtual void TakeSelection() override;
virtual void SetSelected(bool aSelect) override;
// Methods that interact with content.
virtual void TakeFocus() const override;
virtual void ScrollTo(uint32_t aHow) const override;
virtual void SetCaretOffset(int32_t aOffset) override;
* Allow the platform to store a pointers worth of data on us.
uintptr_t GetWrapper() const { return mWrapper; }
void SetWrapper(uintptr_t aWrapper) { mWrapper = aWrapper; }
virtual uint64_t ID() const override { return mID; }
* Return the document containing this proxy, or the proxy itself if it is a
* document.
DocAccessibleParent* Document() const { return mDoc; }
DocAccessibleParent* AsDoc() const { return IsDoc() ? mDoc : nullptr; }
void ApplyCache(CacheUpdateType aUpdateType, AccAttributes* aFields);
void UpdateStateCache(uint64_t aState, bool aEnabled) {
if (aState & kRemoteCalculatedStates) {
uint64_t state = 0;
if (mCachedFields) {
if (auto oldState =
mCachedFields->GetAttribute<uint64_t>(CacheKey::State)) {
state = *oldState;
} else {
mCachedFields = new AccAttributes();
if (aEnabled) {
state |= aState;
} else {
state &= ~aState;
mCachedFields->SetAttribute(CacheKey::State, state);
void InvalidateGroupInfo();
virtual void AppendTextTo(nsAString& aText, uint32_t aStartOffset = 0,
uint32_t aLength = UINT32_MAX) override;
virtual bool TableIsProbablyForLayout();
* Iterates through each atom in kRelationTypeAtoms, checking to see
* if it is present in aFields. If it is present (or if aFields contains
* a DeleteEntry() for this atom) and mCachedFields is initialized,
* fetches the old rel targets and removes their existing reverse relations
* stored in mReverseRelations.
* Returns an array of bools where the ith array entry corresponds
* to whether or not the rel at the ith entry of kRelationTypeAtoms
* requires a post-processing update.
nsTArray<bool> PreProcessRelations(AccAttributes* aFields);
* Takes in the array returned from PreProcessRelations.
* For each entry requiring an update, fetches the new relation
* targets stored in mCachedFields and appropriately
* updates their reverse relations in mReverseRelations.
void PostProcessRelations(const nsTArray<bool>& aToUpdate);
* This method is called during shutdown, before we clear our
* reverse rel map from the document's mReverseRelations cache.
* Here, we traverse our reverse relations, removing our ID from
* the corresponding forward relation's target list. This ensures
* the stored forward relations do not reference defunct accessibles.
void PruneRelationsOnShutdown();
uint32_t GetCachedTextLength();
Maybe<const nsTArray<int32_t>&> GetCachedTextLines();
nsRect GetCachedCharRect(int32_t aOffset);
RefPtr<const AccAttributes> GetCachedTextAttributes();
RefPtr<const AccAttributes> GetCachedARIAAttributes() const;
nsString GetCachedHTMLNameAttribute() const;
virtual HyperTextAccessibleBase* AsHyperTextBase() override {
return IsHyperText() ? static_cast<HyperTextAccessibleBase*>(this)
: nullptr;
virtual TableAccessible* AsTable() override;
virtual TableCellAccessible* AsTableCell() override;
virtual void DOMNodeID(nsString& aID) const override;
virtual void DOMNodeClass(nsString& aClass) const override;
virtual void ScrollToPoint(uint32_t aScrollType, int32_t aX,
int32_t aY) override;
#if !defined(XP_WIN)
void Announce(const nsString& aAnnouncement, uint16_t aPriority);
#endif // !defined(XP_WIN)
// HTMLMeterAccessible
int32_t ValueRegion() const;
// HyperTextAccessibleBase
virtual already_AddRefed<AccAttributes> DefaultTextAttributes() override;
virtual void ScrollSubstringToPoint(int32_t aStartOffset, int32_t aEndOffset,
uint32_t aCoordinateType, int32_t aX,
int32_t aY) override;
* Invalidate cached HyperText offsets. This should be called whenever a
* child is added or removed or the text of a text leaf child is changed.
* Although GetChildOffset can either fully or partially invalidate the
* offsets cache, calculating which offset to invalidate is not worthwhile
* because a client might not even query offsets. This is in contrast to
* LocalAccessible, where the offsets are always needed to fire text change
* events. For RemoteAccessible, it's cheaper overall to just rebuild the
* offsets cache when a client next needs it.
void InvalidateCachedHyperTextOffsets() {
if (mCachedFields) {
size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf);
virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf);
RemoteAccessible(uint64_t aID, DocAccessibleParent* aDoc, role aRole,
AccType aType, AccGenericType aGenericTypes,
uint8_t aRoleMapEntryIndex)
: Accessible(aType, aGenericTypes, aRoleMapEntryIndex),
mRole(aRole) {
explicit RemoteAccessible(DocAccessibleParent* aThisAsDoc)
: mParent(kNoParent),
mRole(roles::DOCUMENT) {
mGenericTypes = eDocument | eHyperText;
void SetParent(RemoteAccessible* aParent);
Maybe<nsRect> RetrieveCachedBounds() const;
bool ApplyTransform(nsRect& aCumulativeBounds) const;
bool ApplyScrollOffset(nsRect& aBounds) const;
void ApplyCrossDocOffset(nsRect& aBounds) const;
LayoutDeviceIntRect BoundsWithOffset(
Maybe<nsRect> aOffset, bool aBoundsAreForHittesting = false) const;
bool IsFixedPos() const;
bool IsOverflowHidden() const;
* Returns true if an accessible's frame has no scrollable overflow, and
* false otherwise.
* Does not return true for partially clipped accessibles.
bool IsClipped() const;
* Checks if our hittesting match has any clipped children and, if so
* descends it and subsequent TEXT_CONTAINERs in search of a text leaf.
* We do this because some sites use clipping to hide text that is only
* visible to a11y, while displaying a visual version of the same text on
* the web page. We want a hittest of the visible text to resolve to the
* hidden, a11y-only text node.
RemoteAccessible* DoFuzzyHittesting();
// This function is used exclusively for hit testing.
bool ContainsPoint(int32_t aX, int32_t aY);
virtual void ARIAGroupPosition(int32_t* aLevel, int32_t* aSetSize,
int32_t* aPosInSet) const override;
virtual AccGroupInfo* GetGroupInfo() const override;
virtual AccGroupInfo* GetOrCreateGroupInfo() override;
virtual void GetPositionAndSetSize(int32_t* aPosInSet,
int32_t* aSetSize) override;
virtual bool HasPrimaryAction() const override;
nsAtom* GetPrimaryAction() const;
virtual nsTArray<int32_t>& GetCachedHyperTextOffsets() override;
uintptr_t mParent;
static const uintptr_t kNoParent = UINTPTR_MAX;
friend DocAccessibleParent;
friend TextLeafPoint;
friend HyperTextAccessibleBase;
friend class xpcAccessible;
friend class CachedTableCellAccessible;
#ifdef XP_WIN
friend class sdnAccessible;
nsTArray<RemoteAccessible*> mChildren;
DocAccessibleParent* mDoc;
uintptr_t mWrapper;
uint64_t mID;
virtual const Accessible* Acc() const override { return this; }
RefPtr<AccAttributes> mCachedFields;
// XXX DocAccessibleParent gets to change this to change the role of
// documents.
role mRole : 27;
// RemoteAccessible downcasting method
inline RemoteAccessible* Accessible::AsRemote() {
return IsRemote() ? static_cast<RemoteAccessible*>(this) : nullptr;
} // namespace a11y
} // namespace mozilla