1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/accessible/src/generic/DocAccessible.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,625 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef mozilla_a11y_DocAccessible_h__
1.10 +#define mozilla_a11y_DocAccessible_h__
1.11 +
1.12 +#include "nsIAccessibleDocument.h"
1.13 +#include "nsIAccessiblePivot.h"
1.14 +
1.15 +#include "AccEvent.h"
1.16 +#include "HyperTextAccessibleWrap.h"
1.17 +
1.18 +#include "nsClassHashtable.h"
1.19 +#include "nsDataHashtable.h"
1.20 +#include "nsIDocument.h"
1.21 +#include "nsIDocumentObserver.h"
1.22 +#include "nsIEditor.h"
1.23 +#include "nsIObserver.h"
1.24 +#include "nsIScrollPositionListener.h"
1.25 +#include "nsITimer.h"
1.26 +#include "nsIWeakReference.h"
1.27 +
1.28 +class nsAccessiblePivot;
1.29 +
1.30 +class nsIScrollableView;
1.31 +
1.32 +const uint32_t kDefaultCacheSize = 256;
1.33 +
1.34 +namespace mozilla {
1.35 +namespace a11y {
1.36 +
1.37 +class DocManager;
1.38 +class NotificationController;
1.39 +class RelatedAccIterator;
1.40 +template<class Class, class Arg>
1.41 +class TNotification;
1.42 +
1.43 +class DocAccessible : public HyperTextAccessibleWrap,
1.44 + public nsIAccessibleDocument,
1.45 + public nsIDocumentObserver,
1.46 + public nsIObserver,
1.47 + public nsIScrollPositionListener,
1.48 + public nsSupportsWeakReference,
1.49 + public nsIAccessiblePivotObserver
1.50 +{
1.51 + NS_DECL_ISUPPORTS_INHERITED
1.52 + NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DocAccessible, Accessible)
1.53 +
1.54 + NS_DECL_NSIACCESSIBLEDOCUMENT
1.55 +
1.56 + NS_DECL_NSIOBSERVER
1.57 +
1.58 + NS_DECL_NSIACCESSIBLEPIVOTOBSERVER
1.59 +
1.60 +public:
1.61 +
1.62 + DocAccessible(nsIDocument* aDocument, nsIContent* aRootContent,
1.63 + nsIPresShell* aPresShell);
1.64 + virtual ~DocAccessible();
1.65 +
1.66 + // nsIAccessible
1.67 + NS_IMETHOD TakeFocus(void);
1.68 +
1.69 + // nsIScrollPositionListener
1.70 + virtual void ScrollPositionWillChange(nscoord aX, nscoord aY) {}
1.71 + virtual void ScrollPositionDidChange(nscoord aX, nscoord aY);
1.72 +
1.73 + // nsIDocumentObserver
1.74 + NS_DECL_NSIDOCUMENTOBSERVER
1.75 +
1.76 + // Accessible
1.77 + virtual void Init();
1.78 + virtual void Shutdown();
1.79 + virtual nsIFrame* GetFrame() const;
1.80 + virtual nsINode* GetNode() const { return mDocumentNode; }
1.81 + nsIDocument* DocumentNode() const { return mDocumentNode; }
1.82 +
1.83 + virtual mozilla::a11y::ENameValueFlag Name(nsString& aName);
1.84 + virtual void Description(nsString& aDescription);
1.85 + virtual Accessible* FocusedChild();
1.86 + virtual mozilla::a11y::role NativeRole();
1.87 + virtual uint64_t NativeState();
1.88 + virtual uint64_t NativeInteractiveState() const;
1.89 + virtual bool NativelyUnavailable() const;
1.90 + virtual void ApplyARIAState(uint64_t* aState) const;
1.91 + virtual already_AddRefed<nsIPersistentProperties> Attributes();
1.92 +
1.93 +#ifdef A11Y_LOG
1.94 + virtual nsresult HandleAccEvent(AccEvent* aEvent);
1.95 +#endif
1.96 +
1.97 + virtual void GetBoundsRect(nsRect& aRect, nsIFrame** aRelativeFrame);
1.98 +
1.99 + // HyperTextAccessible
1.100 + virtual already_AddRefed<nsIEditor> GetEditor() const;
1.101 +
1.102 + // DocAccessible
1.103 +
1.104 + /**
1.105 + * Return presentation shell for this document accessible.
1.106 + */
1.107 + nsIPresShell* PresShell() const { return mPresShell; }
1.108 +
1.109 + /**
1.110 + * Return the presentation shell's context.
1.111 + */
1.112 + nsPresContext* PresContext() const { return mPresShell->GetPresContext(); }
1.113 +
1.114 + /**
1.115 + * Return true if associated DOM document was loaded and isn't unloading.
1.116 + */
1.117 + bool IsContentLoaded() const
1.118 + {
1.119 + // eDOMLoaded flag check is used for error pages as workaround to make this
1.120 + // method return correct result since error pages do not receive 'pageshow'
1.121 + // event and as consequence nsIDocument::IsShowing() returns false.
1.122 + return mDocumentNode && mDocumentNode->IsVisible() &&
1.123 + (mDocumentNode->IsShowing() || HasLoadState(eDOMLoaded));
1.124 + }
1.125 +
1.126 + /**
1.127 + * Document load states.
1.128 + */
1.129 + enum LoadState {
1.130 + // initial tree construction is pending
1.131 + eTreeConstructionPending = 0,
1.132 + // initial tree construction done
1.133 + eTreeConstructed = 1,
1.134 + // DOM document is loaded.
1.135 + eDOMLoaded = 1 << 1,
1.136 + // document is ready
1.137 + eReady = eTreeConstructed | eDOMLoaded,
1.138 + // document and all its subdocuments are ready
1.139 + eCompletelyLoaded = eReady | 1 << 2
1.140 + };
1.141 +
1.142 + /**
1.143 + * Return true if the document has given document state.
1.144 + */
1.145 + bool HasLoadState(LoadState aState) const
1.146 + { return (mLoadState & static_cast<uint32_t>(aState)) ==
1.147 + static_cast<uint32_t>(aState); }
1.148 +
1.149 + /**
1.150 + * Return a native window handler or pointer depending on platform.
1.151 + */
1.152 + virtual void* GetNativeWindow() const;
1.153 +
1.154 + /**
1.155 + * Return the parent document.
1.156 + */
1.157 + DocAccessible* ParentDocument() const
1.158 + { return mParent ? mParent->Document() : nullptr; }
1.159 +
1.160 + /**
1.161 + * Return the child document count.
1.162 + */
1.163 + uint32_t ChildDocumentCount() const
1.164 + { return mChildDocuments.Length(); }
1.165 +
1.166 + /**
1.167 + * Return the child document at the given index.
1.168 + */
1.169 + DocAccessible* GetChildDocumentAt(uint32_t aIndex) const
1.170 + { return mChildDocuments.SafeElementAt(aIndex, nullptr); }
1.171 +
1.172 + /**
1.173 + * Fire accessible event asynchronously.
1.174 + */
1.175 + void FireDelayedEvent(AccEvent* aEvent);
1.176 + void FireDelayedEvent(uint32_t aEventType, Accessible* aTarget);
1.177 +
1.178 + /**
1.179 + * Fire value change event on the given accessible if applicable.
1.180 + */
1.181 + void MaybeNotifyOfValueChange(Accessible* aAccessible);
1.182 +
1.183 + /**
1.184 + * Get/set the anchor jump.
1.185 + */
1.186 + Accessible* AnchorJump()
1.187 + { return GetAccessibleOrContainer(mAnchorJumpElm); }
1.188 +
1.189 + void SetAnchorJump(nsIContent* aTargetNode)
1.190 + { mAnchorJumpElm = aTargetNode; }
1.191 +
1.192 + /**
1.193 + * Bind the child document to the tree.
1.194 + */
1.195 + void BindChildDocument(DocAccessible* aDocument);
1.196 +
1.197 + /**
1.198 + * Process the generic notification.
1.199 + *
1.200 + * @note The caller must guarantee that the given instance still exists when
1.201 + * notification is processed.
1.202 + * @see NotificationController::HandleNotification
1.203 + */
1.204 + template<class Class, class Arg>
1.205 + void HandleNotification(Class* aInstance,
1.206 + typename TNotification<Class, Arg>::Callback aMethod,
1.207 + Arg* aArg);
1.208 +
1.209 + /**
1.210 + * Return the cached accessible by the given DOM node if it's in subtree of
1.211 + * this document accessible or the document accessible itself, otherwise null.
1.212 + *
1.213 + * @return the accessible object
1.214 + */
1.215 + Accessible* GetAccessible(nsINode* aNode) const;
1.216 +
1.217 + /**
1.218 + * Return an accessible for the given node even if the node is not in
1.219 + * document's node map cache (like HTML area element).
1.220 + *
1.221 + * XXX: it should be really merged with GetAccessible().
1.222 + */
1.223 + Accessible* GetAccessibleEvenIfNotInMap(nsINode* aNode) const;
1.224 + Accessible* GetAccessibleEvenIfNotInMapOrContainer(nsINode* aNode) const;
1.225 +
1.226 + /**
1.227 + * Return whether the given DOM node has an accessible or not.
1.228 + */
1.229 + bool HasAccessible(nsINode* aNode) const
1.230 + { return GetAccessible(aNode); }
1.231 +
1.232 + /**
1.233 + * Return the cached accessible by the given unique ID within this document.
1.234 + *
1.235 + * @note the unique ID matches with the uniqueID() of Accessible
1.236 + *
1.237 + * @param aUniqueID [in] the unique ID used to cache the node.
1.238 + */
1.239 + Accessible* GetAccessibleByUniqueID(void* aUniqueID)
1.240 + {
1.241 + return UniqueID() == aUniqueID ?
1.242 + this : mAccessibleCache.GetWeak(aUniqueID);
1.243 + }
1.244 +
1.245 + /**
1.246 + * Return the cached accessible by the given unique ID looking through
1.247 + * this and nested documents.
1.248 + */
1.249 + Accessible* GetAccessibleByUniqueIDInSubtree(void* aUniqueID);
1.250 +
1.251 + /**
1.252 + * Return an accessible for the given DOM node or container accessible if
1.253 + * the node is not accessible.
1.254 + */
1.255 + Accessible* GetAccessibleOrContainer(nsINode* aNode) const;
1.256 +
1.257 + /**
1.258 + * Return a container accessible for the given DOM node.
1.259 + */
1.260 + Accessible* GetContainerAccessible(nsINode* aNode) const
1.261 + {
1.262 + return aNode ? GetAccessibleOrContainer(aNode->GetParentNode()) : nullptr;
1.263 + }
1.264 +
1.265 + /**
1.266 + * Return an accessible for the given node or its first accessible descendant.
1.267 + */
1.268 + Accessible* GetAccessibleOrDescendant(nsINode* aNode) const;
1.269 +
1.270 + /**
1.271 + * Return true if the given ID is referred by relation attribute.
1.272 + *
1.273 + * @note Different elements may share the same ID if they are hosted inside
1.274 + * XBL bindings. Be careful the result of this method may be senseless
1.275 + * while it's called for XUL elements (where XBL is used widely).
1.276 + */
1.277 + bool IsDependentID(const nsAString& aID) const
1.278 + { return mDependentIDsHash.Get(aID, nullptr); }
1.279 +
1.280 + /**
1.281 + * Initialize the newly created accessible and put it into document caches.
1.282 + *
1.283 + * @param aAccessible [in] created accessible
1.284 + * @param aRoleMapEntry [in] the role map entry role the ARIA role or nullptr
1.285 + * if none
1.286 + */
1.287 + void BindToDocument(Accessible* aAccessible, nsRoleMapEntry* aRoleMapEntry);
1.288 +
1.289 + /**
1.290 + * Remove from document and shutdown the given accessible.
1.291 + */
1.292 + void UnbindFromDocument(Accessible* aAccessible);
1.293 +
1.294 + /**
1.295 + * Notify the document accessible that content was inserted.
1.296 + */
1.297 + void ContentInserted(nsIContent* aContainerNode,
1.298 + nsIContent* aStartChildNode,
1.299 + nsIContent* aEndChildNode);
1.300 +
1.301 + /**
1.302 + * Notify the document accessible that content was removed.
1.303 + */
1.304 + void ContentRemoved(nsIContent* aContainerNode, nsIContent* aChildNode);
1.305 +
1.306 + /**
1.307 + * Updates accessible tree when rendered text is changed.
1.308 + */
1.309 + void UpdateText(nsIContent* aTextNode);
1.310 +
1.311 + /**
1.312 + * Recreate an accessible, results in hide/show events pair.
1.313 + */
1.314 + void RecreateAccessible(nsIContent* aContent);
1.315 +
1.316 +protected:
1.317 +
1.318 + void LastRelease();
1.319 +
1.320 + // Accessible
1.321 + virtual void CacheChildren();
1.322 +
1.323 + // DocAccessible
1.324 + virtual nsresult AddEventListeners();
1.325 + virtual nsresult RemoveEventListeners();
1.326 +
1.327 + /**
1.328 + * Marks this document as loaded or loading.
1.329 + */
1.330 + void NotifyOfLoad(uint32_t aLoadEventType);
1.331 + void NotifyOfLoading(bool aIsReloading);
1.332 +
1.333 + friend class DocManager;
1.334 +
1.335 + /**
1.336 + * Perform initial update (create accessible tree).
1.337 + * Can be overridden by wrappers to prepare initialization work.
1.338 + */
1.339 + virtual void DoInitialUpdate();
1.340 +
1.341 + /**
1.342 + * Process document load notification, fire document load and state busy
1.343 + * events if applicable.
1.344 + */
1.345 + void ProcessLoad();
1.346 +
1.347 + /**
1.348 + * Add/remove scroll listeners, @see nsIScrollPositionListener interface.
1.349 + */
1.350 + void AddScrollListener();
1.351 + void RemoveScrollListener();
1.352 +
1.353 + /**
1.354 + * Append the given document accessible to this document's child document
1.355 + * accessibles.
1.356 + */
1.357 + bool AppendChildDocument(DocAccessible* aChildDocument)
1.358 + {
1.359 + return mChildDocuments.AppendElement(aChildDocument);
1.360 + }
1.361 +
1.362 + /**
1.363 + * Remove the given document accessible from this document's child document
1.364 + * accessibles.
1.365 + */
1.366 + void RemoveChildDocument(DocAccessible* aChildDocument)
1.367 + {
1.368 + mChildDocuments.RemoveElement(aChildDocument);
1.369 + }
1.370 +
1.371 + /**
1.372 + * Add dependent IDs pointed by accessible element by relation attribute to
1.373 + * cache. If the relation attribute is missed then all relation attributes
1.374 + * are checked.
1.375 + *
1.376 + * @param aRelProvider [in] accessible that element has relation attribute
1.377 + * @param aRelAttr [in, optional] relation attribute
1.378 + */
1.379 + void AddDependentIDsFor(dom::Element* aRelProviderElm,
1.380 + nsIAtom* aRelAttr = nullptr);
1.381 +
1.382 + /**
1.383 + * Remove dependent IDs pointed by accessible element by relation attribute
1.384 + * from cache. If the relation attribute is absent then all relation
1.385 + * attributes are checked.
1.386 + *
1.387 + * @param aRelProvider [in] accessible that element has relation attribute
1.388 + * @param aRelAttr [in, optional] relation attribute
1.389 + */
1.390 + void RemoveDependentIDsFor(dom::Element* aRelProviderElm,
1.391 + nsIAtom* aRelAttr = nullptr);
1.392 +
1.393 + /**
1.394 + * Update or recreate an accessible depending on a changed attribute.
1.395 + *
1.396 + * @param aElement [in] the element the attribute was changed on
1.397 + * @param aAttribute [in] the changed attribute
1.398 + * @return true if an action was taken on the attribute change
1.399 + */
1.400 + bool UpdateAccessibleOnAttrChange(mozilla::dom::Element* aElement,
1.401 + nsIAtom* aAttribute);
1.402 +
1.403 + /**
1.404 + * Fire accessible events when attribute is changed.
1.405 + *
1.406 + * @param aAccessible [in] accessible the DOM attribute is changed for
1.407 + * @param aNameSpaceID [in] namespace of changed attribute
1.408 + * @param aAttribute [in] changed attribute
1.409 + */
1.410 + void AttributeChangedImpl(Accessible* aAccessible,
1.411 + int32_t aNameSpaceID, nsIAtom* aAttribute);
1.412 +
1.413 + /**
1.414 + * Fire accessible events when ARIA attribute is changed.
1.415 + *
1.416 + * @param aAccessible [in] accesislbe the DOM attribute is changed for
1.417 + * @param aAttribute [in] changed attribute
1.418 + */
1.419 + void ARIAAttributeChanged(Accessible* aAccessible, nsIAtom* aAttribute);
1.420 +
1.421 + /**
1.422 + * Process ARIA active-descendant attribute change.
1.423 + */
1.424 + void ARIAActiveDescendantChanged(Accessible* aAccessible);
1.425 +
1.426 + /**
1.427 + * Update the accessible tree for inserted content.
1.428 + */
1.429 + void ProcessContentInserted(Accessible* aContainer,
1.430 + const nsTArray<nsCOMPtr<nsIContent> >* aInsertedContent);
1.431 +
1.432 + /**
1.433 + * Used to notify the document to make it process the invalidation list.
1.434 + *
1.435 + * While children are cached we may encounter the case there's no accessible
1.436 + * for referred content by related accessible. Store these related nodes to
1.437 + * invalidate their containers later.
1.438 + */
1.439 + void ProcessInvalidationList();
1.440 +
1.441 + /**
1.442 + * Update the accessible tree for content insertion or removal.
1.443 + */
1.444 + void UpdateTree(Accessible* aContainer, nsIContent* aChildNode,
1.445 + bool aIsInsert);
1.446 +
1.447 + /**
1.448 + * Helper for UpdateTree() method. Go down to DOM subtree and updates
1.449 + * accessible tree. Return one of these flags.
1.450 + */
1.451 + enum EUpdateTreeFlags {
1.452 + eNoAccessible = 0,
1.453 + eAccessible = 1,
1.454 + eAlertAccessible = 2
1.455 + };
1.456 +
1.457 + uint32_t UpdateTreeInternal(Accessible* aChild, bool aIsInsert,
1.458 + AccReorderEvent* aReorderEvent);
1.459 +
1.460 + /**
1.461 + * Create accessible tree.
1.462 + *
1.463 + * @param aRoot [in] a root of subtree to create
1.464 + * @param aFocusedAcc [in, optional] a focused accessible under created
1.465 + * subtree if any
1.466 + */
1.467 + void CacheChildrenInSubtree(Accessible* aRoot,
1.468 + Accessible** aFocusedAcc = nullptr);
1.469 +
1.470 + /**
1.471 + * Remove accessibles in subtree from node to accessible map.
1.472 + */
1.473 + void UncacheChildrenInSubtree(Accessible* aRoot);
1.474 +
1.475 + /**
1.476 + * Shutdown any cached accessible in the subtree.
1.477 + *
1.478 + * @param aAccessible [in] the root of the subrtee to invalidate accessible
1.479 + * child/parent refs in
1.480 + */
1.481 + void ShutdownChildrenInSubtree(Accessible* aAccessible);
1.482 +
1.483 + /**
1.484 + * Return true if the document is a target of document loading events
1.485 + * (for example, state busy change or document reload events).
1.486 + *
1.487 + * Rules: The root chrome document accessible is never an event target
1.488 + * (for example, Firefox UI window). If the sub document is loaded within its
1.489 + * parent document then the parent document is a target only (aka events
1.490 + * coalescence).
1.491 + */
1.492 + bool IsLoadEventTarget() const;
1.493 +
1.494 + /**
1.495 + * Used to fire scrolling end event after page scroll.
1.496 + *
1.497 + * @param aTimer [in] the timer object
1.498 + * @param aClosure [in] the document accessible where scrolling happens
1.499 + */
1.500 + static void ScrollTimerCallback(nsITimer* aTimer, void* aClosure);
1.501 +
1.502 +protected:
1.503 +
1.504 + /**
1.505 + * State and property flags, kept by mDocFlags.
1.506 + */
1.507 + enum {
1.508 + // Whether scroll listeners were added.
1.509 + eScrollInitialized = 1 << 0,
1.510 +
1.511 + // Whether the document is a tab document.
1.512 + eTabDocument = 1 << 1
1.513 + };
1.514 +
1.515 + /**
1.516 + * Cache of accessibles within this document accessible.
1.517 + */
1.518 + AccessibleHashtable mAccessibleCache;
1.519 + nsDataHashtable<nsPtrHashKey<const nsINode>, Accessible*>
1.520 + mNodeToAccessibleMap;
1.521 +
1.522 + nsIDocument* mDocumentNode;
1.523 + nsCOMPtr<nsITimer> mScrollWatchTimer;
1.524 + uint16_t mScrollPositionChangedTicks; // Used for tracking scroll events
1.525 +
1.526 + /**
1.527 + * Bit mask of document load states (@see LoadState).
1.528 + */
1.529 + uint32_t mLoadState : 3;
1.530 +
1.531 + /**
1.532 + * Bit mask of other states and props.
1.533 + */
1.534 + uint32_t mDocFlags : 28;
1.535 +
1.536 + /**
1.537 + * Type of document load event fired after the document is loaded completely.
1.538 + */
1.539 + uint32_t mLoadEventType;
1.540 +
1.541 + /**
1.542 + * Reference to anchor jump element.
1.543 + */
1.544 + nsCOMPtr<nsIContent> mAnchorJumpElm;
1.545 +
1.546 + /**
1.547 + * A generic state (see items below) before the attribute value was changed.
1.548 + * @see AttributeWillChange and AttributeChanged notifications.
1.549 + */
1.550 + union {
1.551 + // ARIA attribute value
1.552 + nsIAtom* mARIAAttrOldValue;
1.553 +
1.554 + // True if the accessible state bit was on
1.555 + bool mStateBitWasOn;
1.556 + };
1.557 +
1.558 + nsTArray<nsRefPtr<DocAccessible> > mChildDocuments;
1.559 +
1.560 + /**
1.561 + * The virtual cursor of the document.
1.562 + */
1.563 + nsRefPtr<nsAccessiblePivot> mVirtualCursor;
1.564 +
1.565 + /**
1.566 + * A storage class for pairing content with one of its relation attributes.
1.567 + */
1.568 + class AttrRelProvider
1.569 + {
1.570 + public:
1.571 + AttrRelProvider(nsIAtom* aRelAttr, nsIContent* aContent) :
1.572 + mRelAttr(aRelAttr), mContent(aContent) { }
1.573 +
1.574 + nsIAtom* mRelAttr;
1.575 + nsCOMPtr<nsIContent> mContent;
1.576 +
1.577 + private:
1.578 + AttrRelProvider();
1.579 + AttrRelProvider(const AttrRelProvider&);
1.580 + AttrRelProvider& operator =(const AttrRelProvider&);
1.581 + };
1.582 +
1.583 + typedef nsTArray<nsAutoPtr<AttrRelProvider> > AttrRelProviderArray;
1.584 + typedef nsClassHashtable<nsStringHashKey, AttrRelProviderArray>
1.585 + DependentIDsHashtable;
1.586 +
1.587 + /**
1.588 + * The cache of IDs pointed by relation attributes.
1.589 + */
1.590 + DependentIDsHashtable mDependentIDsHash;
1.591 +
1.592 + static PLDHashOperator
1.593 + CycleCollectorTraverseDepIDsEntry(const nsAString& aKey,
1.594 + AttrRelProviderArray* aProviders,
1.595 + void* aUserArg);
1.596 +
1.597 + friend class RelatedAccIterator;
1.598 +
1.599 + /**
1.600 + * Used for our caching algorithm. We store the list of nodes that should be
1.601 + * invalidated.
1.602 + *
1.603 + * @see ProcessInvalidationList
1.604 + */
1.605 + nsTArray<nsIContent*> mInvalidationList;
1.606 +
1.607 + /**
1.608 + * Used to process notification from core and accessible events.
1.609 + */
1.610 + nsRefPtr<NotificationController> mNotificationController;
1.611 + friend class EventQueue;
1.612 + friend class NotificationController;
1.613 +
1.614 +private:
1.615 +
1.616 + nsIPresShell* mPresShell;
1.617 +};
1.618 +
1.619 +inline DocAccessible*
1.620 +Accessible::AsDoc()
1.621 +{
1.622 + return IsDoc() ? static_cast<DocAccessible*>(this) : nullptr;
1.623 +}
1.624 +
1.625 +} // namespace a11y
1.626 +} // namespace mozilla
1.627 +
1.628 +#endif
