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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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
#ifndef mozilla_a11y_DocAccessible_h__
#define mozilla_a11y_DocAccessible_h__
#include "HyperTextAccessible.h"
#include "AccEvent.h"
#include "nsClassHashtable.h"
#include "nsTHashMap.h"
#include "mozilla/UniquePtr.h"
#include "nsIDocumentObserver.h"
#include "nsITimer.h"
#include "nsTHashSet.h"
#include "nsWeakReference.h"
const uint32_t kDefaultCacheLength = 128;
namespace mozilla {
class EditorBase;
class PresShell;
namespace dom {
class Document;
}
namespace a11y {
class DocManager;
class NotificationController;
class DocAccessibleChild;
class RelatedAccIterator;
template <class Class, class... Args>
class TNotification;
/**
* An accessibility tree node that originated in a content process and
* represents a document. Tabs, in-process iframes, and out-of-process iframes
* all use this class to represent the doc they contain.
*/
class DocAccessible : public HyperTextAccessible,
public nsIDocumentObserver,
public nsSupportsWeakReference {
NS_DECL_ISUPPORTS_INHERITED
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocAccessible, LocalAccessible)
protected:
typedef mozilla::dom::Document Document;
public:
DocAccessible(Document* aDocument, PresShell* aPresShell);
// nsIDocumentObserver
NS_DECL_NSIDOCUMENTOBSERVER
// LocalAccessible
virtual void Init();
virtual void Shutdown() override;
virtual nsIFrame* GetFrame() const override;
virtual nsINode* GetNode() const override;
Document* DocumentNode() const { return mDocumentNode; }
virtual mozilla::a11y::ENameValueFlag Name(nsString& aName) const override;
virtual void Description(nsString& aDescription) const override;
virtual Accessible* FocusedChild() override;
virtual mozilla::a11y::role NativeRole() const override;
virtual uint64_t NativeState() const override;
virtual uint64_t NativeInteractiveState() const override;
virtual bool NativelyUnavailable() const override;
virtual void ApplyARIAState(uint64_t* aState) const override;
virtual void TakeFocus() const override;
#ifdef A11Y_LOG
virtual nsresult HandleAccEvent(AccEvent* aEvent) override;
#endif
virtual nsRect RelativeBounds(nsIFrame** aRelativeFrame) const override;
// ActionAccessible
virtual bool HasPrimaryAction() const override;
virtual void ActionNameAt(uint8_t aIndex, nsAString& aName) override;
// HyperTextAccessible
virtual already_AddRefed<EditorBase> GetEditor() const override;
// DocAccessible
/**
* Return document URL.
*/
void URL(nsAString& aURL) const;
/**
* Return DOM document title.
*/
void Title(nsString& aTitle) const;
/**
* Return DOM document mime type.
*/
void MimeType(nsAString& aType) const;
/**
* Return DOM document type.
*/
void DocType(nsAString& aType) const;
/**
* Adds an entry to queued cache updates indicating aAcc requires
* a cache update on domain aNewDomain. If we've already queued an update
* for aAcc, aNewDomain is or'd with the existing domain(s)
* and the map is updated. Otherwise, the entry is simply inserted.
* This function also schedules processing on the controller.
* Note that this CANNOT be used for anything which fires events, since events
* must be fired after their associated cache update.
*/
void QueueCacheUpdate(LocalAccessible* aAcc, uint64_t aNewDomain);
/**
* Walks the dependent ids and elements maps for the given accessible and
* queues a CacheDomain::Relations cache update fore each related acc.
* We call this when we observe an ID mutation or when an acc is bound
* to its document.
*/
void QueueCacheUpdateForDependentRelations(LocalAccessible* aAcc);
/**
* Returns true if the instance has shutdown.
*/
bool HasShutdown() const { return !mPresShell; }
/**
* Return presentation shell for this document accessible.
*/
PresShell* PresShellPtr() const {
MOZ_DIAGNOSTIC_ASSERT(!HasShutdown());
return mPresShell;
}
/**
* Return the presentation shell's context.
*/
nsPresContext* PresContext() const;
/**
* Return true if associated DOM document was loaded and isn't unloading.
*/
bool IsContentLoaded() const;
bool IsHidden() const;
void SetViewportCacheDirty(bool aDirty) { mViewportCacheDirty = aDirty; }
/**
* Document load states.
*/
enum LoadState {
// initial tree construction is pending
eTreeConstructionPending = 0,
// initial tree construction done
eTreeConstructed = 1,
// DOM document is loaded.
eDOMLoaded = 1 << 1,
// document is ready
eReady = eTreeConstructed | eDOMLoaded,
// document and all its subdocuments are ready
eCompletelyLoaded = eReady | 1 << 2
};
/**
* Return true if the document has given document state.
*/
bool HasLoadState(LoadState aState) const {
return (mLoadState & static_cast<uint32_t>(aState)) ==
static_cast<uint32_t>(aState);
}
/**
* Return a native window handler or pointer depending on platform.
*/
virtual void* GetNativeWindow() const;
/**
* Return the parent document.
*/
DocAccessible* ParentDocument() const {
return mParent ? mParent->Document() : nullptr;
}
/**
* Return the child document count.
*/
uint32_t ChildDocumentCount() const { return mChildDocuments.Length(); }
/**
* Return the child document at the given index.
*/
DocAccessible* GetChildDocumentAt(uint32_t aIndex) const {
return mChildDocuments.SafeElementAt(aIndex, nullptr);
}
/**
* Fire accessible event asynchronously.
*/
void FireDelayedEvent(AccEvent* aEvent);
void FireDelayedEvent(uint32_t aEventType, LocalAccessible* aTarget);
void FireEventsOnInsertion(LocalAccessible* aContainer);
/**
* Fire value change event on the given accessible if applicable.
*/
void MaybeNotifyOfValueChange(LocalAccessible* aAccessible);
/**
* Get/set the anchor jump.
*/
LocalAccessible* AnchorJump() {
return GetAccessibleOrContainer(mAnchorJumpElm);
}
void SetAnchorJump(nsIContent* aTargetNode) { mAnchorJumpElm = aTargetNode; }
/**
* Bind the child document to the tree.
*/
void BindChildDocument(DocAccessible* aDocument);
/**
* Process the generic notification.
*
* @note The caller must guarantee that the given instance still exists when
* notification is processed.
* @see NotificationController::HandleNotification
*/
template <class Class, class... Args>
void HandleNotification(
Class* aInstance,
typename TNotification<Class, Args...>::Callback aMethod, Args*... aArgs);
/**
* Return the cached accessible by the given DOM node if it's in subtree of
* this document accessible or the document accessible itself, otherwise null.
*
* @return the accessible object
*/
LocalAccessible* GetAccessible(nsINode* aNode) const;
/**
* Return an accessible for the given node even if the node is not in
* document's node map cache (like HTML area element).
*
* XXX: it should be really merged with GetAccessible().
*/
LocalAccessible* GetAccessibleEvenIfNotInMap(nsINode* aNode) const;
LocalAccessible* GetAccessibleEvenIfNotInMapOrContainer(nsINode* aNode) const;
/**
* Return whether the given DOM node has an accessible or not.
*/
bool HasAccessible(nsINode* aNode) const { return GetAccessible(aNode); }
/**
* Return the cached accessible by the given unique ID within this document.
*
* @note the unique ID matches with the uniqueID() of Accessible
*
* @param aUniqueID [in] the unique ID used to cache the node.
*/
LocalAccessible* GetAccessibleByUniqueID(void* aUniqueID) {
return UniqueID() == aUniqueID ? this : mAccessibleCache.GetWeak(aUniqueID);
}
/**
* Return the cached accessible by the given unique ID looking through
* this and nested documents.
*/
LocalAccessible* GetAccessibleByUniqueIDInSubtree(void* aUniqueID);
/**
* Return an accessible for the given DOM node or container accessible if
* the node is not accessible. If aNoContainerIfPruned is true it will return
* null if the node is in a pruned subtree (eg. aria-hidden or unselected deck
* panel)
*/
LocalAccessible* GetAccessibleOrContainer(
nsINode* aNode, bool aNoContainerIfPruned = false) const;
/**
* Return a container accessible for the given DOM node.
*/
LocalAccessible* GetContainerAccessible(nsINode* aNode) const;
/**
* Return an accessible for the given node if any, or an immediate accessible
* container for it.
*/
LocalAccessible* AccessibleOrTrueContainer(
nsINode* aNode, bool aNoContainerIfPruned = false) const;
/**
* Return an accessible for the given node or its first accessible descendant.
*/
LocalAccessible* GetAccessibleOrDescendant(nsINode* aNode) const;
/**
* Returns aria-owns seized child at the given index.
*/
LocalAccessible* ARIAOwnedAt(LocalAccessible* aParent,
uint32_t aIndex) const {
nsTArray<RefPtr<LocalAccessible>>* children = mARIAOwnsHash.Get(aParent);
if (children) {
return children->SafeElementAt(aIndex);
}
return nullptr;
}
uint32_t ARIAOwnedCount(LocalAccessible* aParent) const {
nsTArray<RefPtr<LocalAccessible>>* children = mARIAOwnsHash.Get(aParent);
return children ? children->Length() : 0;
}
/**
* Return true if the given ID is referred by relation attribute.
*/
bool IsDependentID(dom::Element* aElement, const nsAString& aID) const {
return GetRelProviders(aElement, aID);
}
/**
* Initialize the newly created accessible and put it into document caches.
*
* @param aAccessible [in] created accessible
* @param aRoleMapEntry [in] the role map entry role the ARIA role or
* nullptr if none
*/
void BindToDocument(LocalAccessible* aAccessible,
const nsRoleMapEntry* aRoleMapEntry);
/**
* Remove from document and shutdown the given accessible.
*/
void UnbindFromDocument(LocalAccessible* aAccessible);
/**
* Notify the document accessible that content was inserted.
*/
void ContentInserted(nsIContent* aStartChildNode, nsIContent* aEndChildNode);
/**
* @see nsAccessibilityService::ScheduleAccessibilitySubtreeUpdate
*/
void ScheduleTreeUpdate(nsIContent* aContent);
/**
* Update the tree on content removal.
*/
void ContentRemoved(LocalAccessible* aAccessible);
void ContentRemoved(nsIContent* aContentNode);
/**
* Updates accessible tree when rendered text is changed.
*/
void UpdateText(nsIContent* aTextNode);
/**
* Recreate an accessible, results in hide/show events pair.
*/
void RecreateAccessible(nsIContent* aContent);
/**
* Schedule ARIA owned element relocation if needed. Return true if relocation
* was scheduled.
*/
bool RelocateARIAOwnedIfNeeded(nsIContent* aEl);
/**
* Return a notification controller associated with the document.
*/
NotificationController* Controller() const { return mNotificationController; }
/**
* If this document is in a content process return the object responsible for
* communicating with the main process for it.
*/
DocAccessibleChild* IPCDoc() const { return mIPCDoc; }
/**
* Notify the document that a DOM node has been scrolled. document will
* dispatch throttled accessibility events for scrolling, and a scroll-end
* event. This function also queues a cache update for ScrollPosition.
*/
void HandleScroll(nsINode* aTarget);
/**
* Retrieves the scroll frame (if it exists) for the given accessible
* and returns its scroll position and scroll range. If the given
* accessible is `this`, return the scroll position and range of
* the root scroll frame. Return values have been scaled by the
* PresShell's resolution.
*/
std::pair<nsPoint, nsRect> ComputeScrollData(LocalAccessible* aAcc);
/**
* Only works in content process documents.
*/
bool IsAccessibleBeingMoved(LocalAccessible* aAcc) {
return mMovedAccessibles.Contains(aAcc);
}
void AttrElementWillChange(dom::Element* aElement, nsAtom* aAttr);
void AttrElementChanged(dom::Element* aElement, nsAtom* aAttr);
protected:
virtual ~DocAccessible();
void LastRelease();
// DocAccessible
virtual nsresult AddEventListeners();
virtual nsresult RemoveEventListeners();
/**
* Marks this document as loaded or loading.
*/
void NotifyOfLoad(uint32_t aLoadEventType);
void NotifyOfLoading(bool aIsReloading);
friend class DocManager;
/**
* Perform initial update (create accessible tree).
* Can be overridden by wrappers to prepare initialization work.
*/
virtual void DoInitialUpdate();
/**
* Updates root element and picks up ARIA role on it if any.
*/
void UpdateRootElIfNeeded();
/**
* Process document load notification, fire document load and state busy
* events if applicable.
*/
void ProcessLoad();
/**
* Append the given document accessible to this document's child document
* accessibles.
*/
bool AppendChildDocument(DocAccessible* aChildDocument) {
// pretended earlier, or change the return type to void.
mChildDocuments.AppendElement(aChildDocument);
return true;
}
/**
* Remove the given document accessible from this document's child document
* accessibles.
*/
void RemoveChildDocument(DocAccessible* aChildDocument) {
mChildDocuments.RemoveElement(aChildDocument);
}
/**
* Add dependent IDs pointed by accessible element by relation attribute to
* cache. If the relation attribute is missed then all relation attributes
* are checked.
*
* @param aRelProvider [in] accessible that element has relation attribute
* @param aRelAttr [in, optional] relation attribute
*/
void AddDependentIDsFor(LocalAccessible* aRelProvider,
nsAtom* aRelAttr = nullptr);
/**
* Remove dependent IDs pointed by accessible element by relation attribute
* from cache. If the relation attribute is absent then all relation
* attributes are checked.
*
* @param aRelProvider [in] accessible that element has relation attribute
* @param aRelAttr [in, optional] relation attribute
*/
void RemoveDependentIDsFor(LocalAccessible* aRelProvider,
nsAtom* aRelAttr = nullptr);
/**
* Add dependent elements targeted by a relation attribute on an accessible
* element to the dependent elements cache. This is used for reflected IDL
* attributes which return DOM elements and reflect a content attribute, where
* the IDL attribute has been set to an element. For example, if the
* .popoverTargetElement IDL attribute is set to an element using JS, the
* target element will be added to the dependent elements cache. If the
* relation attribute is not specified, then all relation attributes are
* checked.
*
* @param aRelProvider [in] the accessible with the relation IDL attribute.
* @param aRelAttr [in, optional] the name of the reflected content attribute.
* For example, for the popoverTargetElement IDL attribute, this would be
* "popovertarget".
*/
void AddDependentElementsFor(LocalAccessible* aRelProvider,
nsAtom* aRelAttr = nullptr);
/**
* Remove dependent elements targeted by a relation attribute on an accessible
* element from the dependent elements cache. If the relation attribute is
* not specified, then all relation attributes are checked.
*
* @param aRelProvider [in] the accessible with the relation IDL attribute.
* @param aRelAttr [in, optional] the name of the reflected content attribute.
*/
void RemoveDependentElementsFor(LocalAccessible* aRelProvider,
nsAtom* aRelAttr = nullptr);
/**
* Update or recreate an accessible depending on a changed attribute.
*
* @param aElement [in] the element the attribute was changed on
* @param aAttribute [in] the changed attribute
* @return true if an action was taken on the attribute change
*/
bool UpdateAccessibleOnAttrChange(mozilla::dom::Element* aElement,
nsAtom* aAttribute);
/**
* Process ARIA active-descendant attribute change.
*/
void ARIAActiveDescendantChanged(LocalAccessible* aAccessible);
/**
* Update the accessible tree for inserted content.
*/
void ProcessContentInserted(
LocalAccessible* aContainer,
const nsTArray<nsCOMPtr<nsIContent>>* aInsertedContent);
void ProcessContentInserted(LocalAccessible* aContainer,
nsIContent* aInsertedContent);
/**
* Used to notify the document to make it process the invalidation list.
*
* While children are cached we may encounter the case there's no accessible
* for referred content by related accessible. Store these related nodes to
* invalidate their containers later.
*/
void ProcessInvalidationList();
/**
* Process mPendingUpdates
*/
void ProcessPendingUpdates();
/**
* Called from NotificationController to process this doc's
* queued cache updates. For each acc in the map, this function
* sends a cache update with its corresponding CacheDomain.
*/
void ProcessQueuedCacheUpdates();
/**
* Called from NotificationController before mutation events are processed to
* notify the parent process which Accessibles are being moved (if any).
*/
void SendAccessiblesWillMove();
/**
* Called from NotificationController after all mutation events have been
* processed to clear our data about mutations during this tick.
*/
void ClearMutationData() {
mMovedAccessibles.Clear();
mInsertedAccessibles.Clear();
mRemovedNodes.Clear();
}
/**
* Steals or puts back accessible subtrees.
*/
void DoARIAOwnsRelocation(LocalAccessible* aOwner);
/**
* Moves children back under their original parents.
*/
void PutChildrenBack(nsTArray<RefPtr<LocalAccessible>>* aChildren,
uint32_t aStartIdx);
bool MoveChild(LocalAccessible* aChild, LocalAccessible* aNewParent,
int32_t aIdxInParent);
/**
* Create accessible tree.
*
* @param aRoot [in] a root of subtree to create
* @param aFocusedAcc [in, optional] a focused accessible under created
* subtree if any
*/
void CacheChildrenInSubtree(LocalAccessible* aRoot,
LocalAccessible** aFocusedAcc = nullptr);
void CreateSubtree(LocalAccessible* aRoot);
/**
* Remove accessibles in subtree from node to accessible map.
*/
void UncacheChildrenInSubtree(LocalAccessible* aRoot);
/**
* Shutdown any cached accessible in the subtree.
*
* @param aAccessible [in] the root of the subrtee to invalidate accessible
* child/parent refs in
*/
void ShutdownChildrenInSubtree(LocalAccessible* aAccessible);
/**
* Return true if the document is a target of document loading events
* (for example, state busy change or document reload events).
*
* Rules: The root chrome document accessible is never an event target
* (for example, Firefox UI window). If the sub document is loaded within its
* parent document then the parent document is a target only (aka events
* coalescence).
*/
bool IsLoadEventTarget() const;
/*
* Set the object responsible for communicating with the main process on
* behalf of this document.
*/
void SetIPCDoc(DocAccessibleChild* aIPCDoc);
friend class DocAccessibleChild;
/**
* Used to fire scrolling end event after page scroll.
*
* @param aTimer [in] the timer object
* @param aClosure [in] the document accessible where scrolling happens
*/
static void ScrollTimerCallback(nsITimer* aTimer, void* aClosure);
void DispatchScrollingEvent(nsINode* aTarget, uint32_t aEventType);
/**
* Check if an id attribute change affects aria-activedescendant and handle
* the aria-activedescendant change if appropriate.
* If the currently focused element has aria-activedescendant and an
* element's id changes to match this, the id was probably moved from the
* previous active descendant, thus making this element the new active
* descendant. In that case, accessible focus must be changed accordingly.
*/
void ARIAActiveDescendantIDMaybeMoved(LocalAccessible* aAccessible);
/**
* Traverse content subtree and for each node do one of 3 things:
* 1. Check if content node has an accessible that should be removed and
* remove it.
* 2. Check if content node has an accessible that needs to be recreated.
* Remove it and schedule it for reinsertion.
* 3. Check if content node has no accessible but needs one. Schedule one for
* insertion.
*
* Returns true if the root node should be reinserted.
*/
bool PruneOrInsertSubtree(nsIContent* aRoot);
protected:
/**
* State and property flags, kept by mDocFlags.
*/
enum {
// Whether the document is a top level content document in this process.
eTopLevelContentDocInProcess = 1 << 0
};
/**
* Cache of accessibles within this document accessible.
*/
AccessibleHashtable mAccessibleCache;
nsTHashMap<nsPtrHashKey<const nsINode>, LocalAccessible*>
mNodeToAccessibleMap;
Document* mDocumentNode;
nsCOMPtr<nsITimer> mScrollWatchTimer;
nsTHashMap<nsPtrHashKey<nsINode>, TimeStamp> mLastScrollingDispatch;
/**
* Bit mask of document load states (@see LoadState).
*/
uint32_t mLoadState : 3;
/**
* Bit mask of other states and props.
*/
uint32_t mDocFlags : 27;
/**
* Tracks whether we have seen changes to this document's content that
* indicate we should re-send the viewport cache we use for hittesting.
* This value is set in `BundleFieldsForCache` and processed in
* `ProcessQueuedCacheUpdates`.
*/
bool mViewportCacheDirty : 1;
/**
* Type of document load event fired after the document is loaded completely.
*/
uint32_t mLoadEventType;
/**
* Reference to anchor jump element.
*/
nsCOMPtr<nsIContent> mAnchorJumpElm;
/**
* A generic state (see items below) before the attribute value was changed.
* @see AttributeWillChange and AttributeChanged notifications.
*/
// Previous state bits before attribute change
uint64_t mPrevStateBits;
nsTArray<RefPtr<DocAccessible>> mChildDocuments;
/**
* A storage class for pairing content with one of its relation attributes.
*/
class AttrRelProvider {
public:
AttrRelProvider(nsAtom* aRelAttr, nsIContent* aContent)
: mRelAttr(aRelAttr), mContent(aContent) {}
nsAtom* mRelAttr;
nsCOMPtr<nsIContent> mContent;
private:
AttrRelProvider();
AttrRelProvider(const AttrRelProvider&);
AttrRelProvider& operator=(const AttrRelProvider&);
};
typedef nsTArray<mozilla::UniquePtr<AttrRelProvider>> AttrRelProviders;
typedef nsClassHashtable<nsStringHashKey, AttrRelProviders>
DependentIDsHashtable;
/**
* Returns/creates/removes attribute relation providers associated with
* a DOM document if the element is in uncomposed document or associated
* with shadow DOM the element is in.
*/
AttrRelProviders* GetRelProviders(dom::Element* aElement,
const nsAString& aID) const;
AttrRelProviders* GetOrCreateRelProviders(dom::Element* aElement,
const nsAString& aID);
void RemoveRelProvidersIfEmpty(dom::Element* aElement, const nsAString& aID);
/**
* A map used to look up the target node for an implicit reverse relation
* where the target of the explicit relation is specified as an id.
* For example:
* <div id="label">Name:</div><input aria-labelledby="label">
* The div should get a LABEL_FOR relation targeting the input. To facilitate
* that, mDependentIDsHashes maps from "label" to an AttrRelProvider
* specifying aria-labelledby and the input. Because ids are scoped to the
* nearest ancestor document or shadow root, mDependentIDsHashes maps from the
* DocumentOrShadowRoot first.
*/
nsClassHashtable<nsPtrHashKey<dom::DocumentOrShadowRoot>,
DependentIDsHashtable>
mDependentIDsHashes;
/**
* A map used to look up the target element for an implicit reverse relation
* where the target of the explicit relation is also specified as an element.
* This is similar to mDependentIDsHashes, except that this is used when a
* DOM property is used to set the relation target element directly, rather
* than using an id. For example:
* <button>More info</button><div popover>Some info</div>
* The button's .popoverTargetElement property is set to the div so that the
* button invokes the popover.
* To facilitate finding the invoker given the popover, mDependentElementsMap
* maps from the div to an AttrRelProvider specifying popovertarget and the
* button.
*/
nsTHashMap<nsIContent*, AttrRelProviders> mDependentElementsMap;
friend class RelatedAccIterator;
/**
* Used for our caching algorithm. We store the list of nodes that should be
* invalidated.
*
* @see ProcessInvalidationList
*/
nsTArray<RefPtr<nsIContent>> mInvalidationList;
/**
* Holds a list of aria-owns relocations.
*/
nsClassHashtable<nsPtrHashKey<LocalAccessible>,
nsTArray<RefPtr<LocalAccessible>>>
mARIAOwnsHash;
/**
* Keeps a list of pending subtrees to update post-refresh.
*/
nsTArray<RefPtr<nsIContent>> mPendingUpdates;
/**
* Used to process notification from core and accessible events.
*/
RefPtr<NotificationController> mNotificationController;
friend class EventTree;
friend class NotificationController;
private:
void SetRoleMapEntryForDoc(dom::Element* aElement);
/**
* This must be called whenever an Accessible is moved in a content process.
* It keeps track of Accessibles moved during this tick.
*/
void TrackMovedAccessible(LocalAccessible* aAcc);
/**
* For hidden subtrees, fire a name/description change event if the subtree
* is a target of aria-labelledby/describedby.
* This does nothing if it is called on a node which is not part of a hidden
* aria-labelledby/describedby target.
*/
void MaybeHandleChangeToHiddenNameOrDescription(nsIContent* aChild);
void MaybeFireEventsForChangedPopover(LocalAccessible* aAcc);
PresShell* mPresShell;
// Exclusively owned by IPDL so don't manually delete it!
// Cleared in ActorDestroy
DocAccessibleChild* mIPCDoc;
// These data structures map between LocalAccessibles and CacheDomains,
// tracking cache updates that have been queued during the current tick but
// not yet sent. If there are a lot of nearby text cache updates (e.g. during
// a reflow), it is much more performant to process them in order because we
// then benefit from the layout line cursor. However, we still only want to
// process each LocalAccessible only once. Therefore, we use an array for
// ordering and a hash map to avoid duplicates, since Gecko has no ordered
// set data structure. The array contains pairs of LocalAccessible and cache
// domain. The hash map maps from LocalAccessible to the corresponding index
// in the array. These data structures must be kept in sync. It is possible
// for these to contain a reference to the document they live on. We clear
// them in Shutdown() to avoid cyclical references.
nsTArray<std::pair<RefPtr<LocalAccessible>, uint64_t>>
mQueuedCacheUpdatesArray;
nsTHashMap<LocalAccessible*, size_t> mQueuedCacheUpdatesHash;
// A set of Accessibles moved during this tick. Only used in content
// processes.
nsTHashSet<RefPtr<LocalAccessible>> mMovedAccessibles;
// A set of Accessibles inserted during this tick. Only used in content
// processes. This is needed to prevent insertions + moves of the same
// Accessible in the same tick from being tracked as moves.
nsTHashSet<RefPtr<LocalAccessible>> mInsertedAccessibles;
// A set of DOM nodes removed during this tick. This avoids a lot of pointless
// recursive DOM traversals.
nsTHashSet<nsIContent*> mRemovedNodes;
};
inline DocAccessible* LocalAccessible::AsDoc() {
return IsDoc() ? static_cast<DocAccessible*>(this) : nullptr;
}
} // namespace a11y
} // namespace mozilla
#endif