1/*
2* Copyright (C) 2008 Apple Inc. All rights reserved.
3*
4* Redistribution and use in source and binary forms, with or without
5* modification, are permitted provided that the following conditions
6* are met:
7*
8* 1.  Redistributions of source code must retain the above copyright
9*     notice, this list of conditions and the following disclaimer.
10* 2.  Redistributions in binary form must reproduce the above copyright
11*     notice, this list of conditions and the following disclaimer in the
12*     documentation and/or other materials provided with the distribution.
13* 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14*     its contributors may be used to endorse or promote products derived
15*     from this software without specific prior written permission.
16*
17* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27*/
28
29#include "config.h"
30#include "core/accessibility/AccessibilityRenderObject.h"
31
32#include "bindings/v8/ExceptionStatePlaceholder.h"
33#include "core/accessibility/AXObjectCache.h"
34#include "core/accessibility/AccessibilityImageMapLink.h"
35#include "core/accessibility/AccessibilitySVGRoot.h"
36#include "core/accessibility/AccessibilitySpinButton.h"
37#include "core/accessibility/AccessibilityTable.h"
38#include "core/dom/NodeTraversal.h"
39#include "core/editing/FrameSelection.h"
40#include "core/editing/RenderedPosition.h"
41#include "core/editing/VisibleUnits.h"
42#include "core/editing/htmlediting.h"
43#include "core/html/HTMLHtmlElement.h"
44#include "core/html/HTMLImageElement.h"
45#include "core/html/HTMLLabelElement.h"
46#include "core/html/HTMLOptionElement.h"
47#include "core/html/HTMLSelectElement.h"
48#include "core/html/HTMLTextAreaElement.h"
49#include "core/loader/ProgressTracker.h"
50#include "core/page/Page.h"
51#include "core/platform/LocalizedStrings.h"
52#include "core/rendering/HitTestResult.h"
53#include "core/rendering/RenderFieldset.h"
54#include "core/rendering/RenderFileUploadControl.h"
55#include "core/rendering/RenderHTMLCanvas.h"
56#include "core/rendering/RenderImage.h"
57#include "core/rendering/RenderInline.h"
58#include "core/rendering/RenderLayer.h"
59#include "core/rendering/RenderListMarker.h"
60#include "core/rendering/RenderMenuList.h"
61#include "core/rendering/RenderTextControlSingleLine.h"
62#include "core/rendering/RenderTextFragment.h"
63#include "core/rendering/RenderWidget.h"
64#include "core/svg/SVGDocument.h"
65#include "core/svg/SVGSVGElement.h"
66#include "core/svg/graphics/SVGImage.h"
67#include "wtf/StdLibExtras.h"
68
69using namespace std;
70
71namespace WebCore {
72
73using namespace HTMLNames;
74
75static inline RenderObject* firstChildInContinuation(RenderObject* renderer)
76{
77    RenderObject* r = toRenderInline(renderer)->continuation();
78
79    while (r) {
80        if (r->isRenderBlock())
81            return r;
82        if (RenderObject* child = r->firstChild())
83            return child;
84        r = toRenderInline(r)->continuation();
85    }
86
87    return 0;
88}
89
90static inline bool isInlineWithContinuation(RenderObject* object)
91{
92    if (!object->isBoxModelObject())
93        return false;
94
95    RenderBoxModelObject* renderer = toRenderBoxModelObject(object);
96    if (!renderer->isRenderInline())
97        return false;
98
99    return toRenderInline(renderer)->continuation();
100}
101
102static inline RenderObject* firstChildConsideringContinuation(RenderObject* renderer)
103{
104    RenderObject* firstChild = renderer->firstChild();
105
106    if (!firstChild && isInlineWithContinuation(renderer))
107        firstChild = firstChildInContinuation(renderer);
108
109    return firstChild;
110}
111
112static inline RenderInline* startOfContinuations(RenderObject* r)
113{
114    if (r->isInlineElementContinuation()) {
115        return toRenderInline(r->node()->renderer());
116    }
117
118    // Blocks with a previous continuation always have a next continuation
119    if (r->isRenderBlock() && toRenderBlock(r)->inlineElementContinuation())
120        return toRenderInline(toRenderBlock(r)->inlineElementContinuation()->node()->renderer());
121
122    return 0;
123}
124
125static inline RenderObject* endOfContinuations(RenderObject* renderer)
126{
127    RenderObject* prev = renderer;
128    RenderObject* cur = renderer;
129
130    if (!cur->isRenderInline() && !cur->isRenderBlock())
131        return renderer;
132
133    while (cur) {
134        prev = cur;
135        if (cur->isRenderInline()) {
136            cur = toRenderInline(cur)->inlineElementContinuation();
137            ASSERT(cur || !toRenderInline(prev)->continuation());
138        } else
139            cur = toRenderBlock(cur)->inlineElementContinuation();
140    }
141
142    return prev;
143}
144
145static inline RenderObject* childBeforeConsideringContinuations(RenderInline* r, RenderObject* child)
146{
147    RenderBoxModelObject* curContainer = r;
148    RenderObject* cur = 0;
149    RenderObject* prev = 0;
150
151    while (curContainer) {
152        if (curContainer->isRenderInline()) {
153            cur = curContainer->firstChild();
154            while (cur) {
155                if (cur == child)
156                    return prev;
157                prev = cur;
158                cur = cur->nextSibling();
159            }
160
161            curContainer = toRenderInline(curContainer)->continuation();
162        } else if (curContainer->isRenderBlock()) {
163            if (curContainer == child)
164                return prev;
165
166            prev = curContainer;
167            curContainer = toRenderBlock(curContainer)->inlineElementContinuation();
168        }
169    }
170
171    ASSERT_NOT_REACHED();
172
173    return 0;
174}
175
176static inline bool firstChildIsInlineContinuation(RenderObject* renderer)
177{
178    return renderer->firstChild() && renderer->firstChild()->isInlineElementContinuation();
179}
180
181static inline bool lastChildHasContinuation(RenderObject* renderer)
182{
183    return renderer->lastChild() && isInlineWithContinuation(renderer->lastChild());
184}
185
186static RenderBoxModelObject* nextContinuation(RenderObject* renderer)
187{
188    ASSERT(renderer);
189    if (renderer->isRenderInline() && !renderer->isReplaced())
190        return toRenderInline(renderer)->continuation();
191    if (renderer->isRenderBlock())
192        return toRenderBlock(renderer)->inlineElementContinuation();
193    return 0;
194}
195
196AccessibilityRenderObject::AccessibilityRenderObject(RenderObject* renderer)
197    : AccessibilityNodeObject(renderer->node())
198    , m_renderer(renderer)
199    , m_cachedElementRectDirty(true)
200{
201#ifndef NDEBUG
202    m_renderer->setHasAXObject(true);
203#endif
204}
205
206PassRefPtr<AccessibilityRenderObject> AccessibilityRenderObject::create(RenderObject* renderer)
207{
208    return adoptRef(new AccessibilityRenderObject(renderer));
209}
210
211AccessibilityRenderObject::~AccessibilityRenderObject()
212{
213    ASSERT(isDetached());
214}
215
216LayoutRect AccessibilityRenderObject::elementRect() const
217{
218    if (!m_explicitElementRect.isEmpty())
219        return m_explicitElementRect;
220    if (!m_renderer)
221        return LayoutRect();
222    if (!m_renderer->isBox())
223        return computeElementRect();
224
225    for (const AccessibilityObject* obj = this; obj; obj = obj->parentObject()) {
226        if (obj->isAccessibilityRenderObject())
227            static_cast<const AccessibilityRenderObject*>(obj)->checkCachedElementRect();
228    }
229    for (const AccessibilityObject* obj = this; obj; obj = obj->parentObject()) {
230        if (obj->isAccessibilityRenderObject())
231            static_cast<const AccessibilityRenderObject*>(obj)->updateCachedElementRect();
232    }
233
234    return m_cachedElementRect;
235}
236
237void AccessibilityRenderObject::setRenderer(RenderObject* renderer)
238{
239    m_renderer = renderer;
240    setNode(renderer->node());
241}
242
243RenderBoxModelObject* AccessibilityRenderObject::renderBoxModelObject() const
244{
245    if (!m_renderer || !m_renderer->isBoxModelObject())
246        return 0;
247    return toRenderBoxModelObject(m_renderer);
248}
249
250RenderView* AccessibilityRenderObject::topRenderer() const
251{
252    Document* topDoc = topDocument();
253    if (!topDoc)
254        return 0;
255
256    return topDoc->renderView();
257}
258
259Document* AccessibilityRenderObject::topDocument() const
260{
261    if (!document())
262        return 0;
263    return document()->topDocument();
264}
265
266HTMLLabelElement* AccessibilityRenderObject::labelElementContainer() const
267{
268    if (!m_renderer)
269        return 0;
270
271    // the control element should not be considered part of the label
272    if (isControl())
273        return 0;
274
275    // find if this has a parent that is a label
276    for (Node* parentNode = m_renderer->node(); parentNode; parentNode = parentNode->parentNode()) {
277        if (isHTMLLabelElement(parentNode))
278            return toHTMLLabelElement(parentNode);
279    }
280
281    return 0;
282}
283
284bool AccessibilityRenderObject::shouldNotifyActiveDescendant() const
285{
286    // We want to notify that the combo box has changed its active descendant,
287    // but we do not want to change the focus, because focus should remain with the combo box.
288    if (isComboBox())
289        return true;
290
291    return shouldFocusActiveDescendant();
292}
293
294ScrollableArea* AccessibilityRenderObject::getScrollableAreaIfScrollable() const
295{
296    // If the parent is a scroll view, then this object isn't really scrollable, the parent ScrollView should handle the scrolling.
297    if (parentObject() && parentObject()->isAccessibilityScrollView())
298        return 0;
299
300    if (!m_renderer || !m_renderer->isBox())
301        return 0;
302
303    RenderBox* box = toRenderBox(m_renderer);
304    if (!box->canBeScrolledAndHasScrollableArea())
305        return 0;
306
307    return box->layer();
308}
309
310AccessibilityRole AccessibilityRenderObject::determineAccessibilityRole()
311{
312    if (!m_renderer)
313        return UnknownRole;
314
315    m_ariaRole = determineAriaRoleAttribute();
316
317    Node* node = m_renderer->node();
318    AccessibilityRole ariaRole = ariaRoleAttribute();
319    if (ariaRole != UnknownRole)
320        return ariaRole;
321
322    RenderBoxModelObject* cssBox = renderBoxModelObject();
323
324    if (node && node->isLink()) {
325        if (cssBox && cssBox->isImage())
326            return ImageMapRole;
327        return WebCoreLinkRole;
328    }
329    if (cssBox && cssBox->isListItem())
330        return ListItemRole;
331    if (m_renderer->isListMarker())
332        return ListMarkerRole;
333    if (node && node->hasTagName(buttonTag))
334        return buttonRoleType();
335    if (node && node->hasTagName(legendTag))
336        return LegendRole;
337    if (m_renderer->isText())
338        return StaticTextRole;
339    if (cssBox && cssBox->isImage()) {
340        if (node && node->hasTagName(inputTag))
341            return ariaHasPopup() ? PopUpButtonRole : ButtonRole;
342        if (isSVGImage())
343            return SVGRootRole;
344        return ImageRole;
345    }
346
347    // Note: if JavaScript is disabled, the renderer won't be a RenderHTMLCanvas.
348    if (node && node->hasTagName(canvasTag) && m_renderer->isCanvas())
349        return CanvasRole;
350
351    if (cssBox && cssBox->isRenderView()) {
352        // If the iframe is seamless, it should not be announced as a web area to AT clients.
353        if (document() && document()->shouldDisplaySeamlesslyWithParent())
354            return SeamlessWebAreaRole;
355        return WebAreaRole;
356    }
357
358    if (cssBox && cssBox->isTextField())
359        return TextFieldRole;
360
361    if (cssBox && cssBox->isTextArea())
362        return TextAreaRole;
363
364    if (node && node->hasTagName(inputTag)) {
365        HTMLInputElement* input = toHTMLInputElement(node);
366        if (input->isCheckbox())
367            return CheckBoxRole;
368        if (input->isRadioButton())
369            return RadioButtonRole;
370        if (input->isTextButton())
371            return buttonRoleType();
372
373        const AtomicString& type = input->getAttribute(typeAttr);
374        if (equalIgnoringCase(type, "color"))
375            return ColorWellRole;
376    }
377
378    if (isFileUploadButton())
379        return ButtonRole;
380
381    if (cssBox && cssBox->isMenuList())
382        return PopUpButtonRole;
383
384    if (headingLevel())
385        return HeadingRole;
386
387    if (m_renderer->isSVGImage())
388        return ImageRole;
389    if (m_renderer->isSVGRoot())
390        return SVGRootRole;
391
392    if (node && node->hasTagName(ddTag))
393        return DescriptionListDetailRole;
394
395    if (node && node->hasTagName(dtTag))
396        return DescriptionListTermRole;
397
398    if (node && (node->hasTagName(rpTag) || node->hasTagName(rtTag)))
399        return AnnotationRole;
400
401    // Table sections should be ignored.
402    if (m_renderer->isTableSection())
403        return IgnoredRole;
404
405    if (m_renderer->isHR())
406        return HorizontalRuleRole;
407
408    if (node && node->hasTagName(pTag))
409        return ParagraphRole;
410
411    if (node && isHTMLLabelElement(node))
412        return LabelRole;
413
414    if (node && node->hasTagName(divTag))
415        return DivRole;
416
417    if (node && node->hasTagName(formTag))
418        return FormRole;
419
420    if (node && node->hasTagName(articleTag))
421        return DocumentArticleRole;
422
423    if (node && node->hasTagName(mainTag))
424        return LandmarkMainRole;
425
426    if (node && node->hasTagName(navTag))
427        return LandmarkNavigationRole;
428
429    if (node && node->hasTagName(asideTag))
430        return LandmarkComplementaryRole;
431
432    if (node && node->hasTagName(sectionTag))
433        return DocumentRegionRole;
434
435    if (node && node->hasTagName(addressTag))
436        return LandmarkContentInfoRole;
437
438    // The HTML element should not be exposed as an element. That's what the RenderView element does.
439    if (node && isHTMLHtmlElement(node))
440        return IgnoredRole;
441
442    // There should only be one banner/contentInfo per page. If header/footer are being used within an article or section
443    // then it should not be exposed as whole page's banner/contentInfo
444    if (node && node->hasTagName(headerTag) && !isDescendantOfElementType(articleTag) && !isDescendantOfElementType(sectionTag))
445        return LandmarkBannerRole;
446    if (node && node->hasTagName(footerTag) && !isDescendantOfElementType(articleTag) && !isDescendantOfElementType(sectionTag))
447        return FooterRole;
448
449    if (m_renderer->isBlockFlow())
450        return GroupRole;
451
452    // If the element does not have role, but it has ARIA attributes, accessibility should fallback to exposing it as a group.
453    if (supportsARIAAttributes())
454        return GroupRole;
455
456    return UnknownRole;
457}
458
459void AccessibilityRenderObject::init()
460{
461    AccessibilityNodeObject::init();
462}
463
464void AccessibilityRenderObject::detach()
465{
466    AccessibilityNodeObject::detach();
467
468    detachRemoteSVGRoot();
469
470#ifndef NDEBUG
471    if (m_renderer)
472        m_renderer->setHasAXObject(false);
473#endif
474    m_renderer = 0;
475}
476
477//
478// Check object role or purpose.
479//
480
481bool AccessibilityRenderObject::isAttachment() const
482{
483    RenderBoxModelObject* renderer = renderBoxModelObject();
484    if (!renderer)
485        return false;
486    // Widgets are the replaced elements that we represent to AX as attachments
487    bool isWidget = renderer->isWidget();
488    ASSERT(!isWidget || (renderer->isReplaced() && !isImage()));
489    return isWidget;
490}
491
492bool AccessibilityRenderObject::isFileUploadButton() const
493{
494    if (m_renderer && m_renderer->node() && m_renderer->node()->hasTagName(inputTag)) {
495        HTMLInputElement* input = toHTMLInputElement(m_renderer->node());
496        return input->isFileUpload();
497    }
498
499    return false;
500}
501
502static bool isLinkable(const AccessibilityObject& object)
503{
504    if (!object.renderer())
505        return false;
506
507    // See https://wiki.mozilla.org/Accessibility/AT-Windows-API for the elements
508    // Mozilla considers linkable.
509    return object.isLink() || object.isImage() || object.renderer()->isText();
510}
511
512bool AccessibilityRenderObject::isLinked() const
513{
514    if (!isLinkable(*this))
515        return false;
516
517    Element* anchor = anchorElement();
518    if (!anchor || !isHTMLAnchorElement(anchor))
519        return false;
520
521    return !toHTMLAnchorElement(anchor)->href().isEmpty();
522}
523
524bool AccessibilityRenderObject::isLoaded() const
525{
526    return !m_renderer->document()->parser();
527}
528
529bool AccessibilityRenderObject::isOffScreen() const
530{
531    ASSERT(m_renderer);
532    IntRect contentRect = pixelSnappedIntRect(m_renderer->absoluteClippedOverflowRect());
533    FrameView* view = m_renderer->frame()->view();
534    IntRect viewRect = view->visibleContentRect();
535    viewRect.intersect(contentRect);
536    return viewRect.isEmpty();
537}
538
539bool AccessibilityRenderObject::isReadOnly() const
540{
541    ASSERT(m_renderer);
542
543    if (isWebArea()) {
544        Document* document = m_renderer->document();
545        if (!document)
546            return true;
547
548        HTMLElement* body = document->body();
549        if (body && body->rendererIsEditable())
550            return false;
551
552        return !document->rendererIsEditable();
553    }
554
555    return AccessibilityNodeObject::isReadOnly();
556}
557
558bool AccessibilityRenderObject::isVisited() const
559{
560    // FIXME: Is it a privacy violation to expose visited information to accessibility APIs?
561    return m_renderer->style()->isLink() && m_renderer->style()->insideLink() == InsideVisitedLink;
562}
563
564//
565// Check object state.
566//
567
568bool AccessibilityRenderObject::isFocused() const
569{
570    if (!m_renderer)
571        return false;
572
573    Document* document = m_renderer->document();
574    if (!document)
575        return false;
576
577    Element* focusedElement = document->focusedElement();
578    if (!focusedElement)
579        return false;
580
581    // A web area is represented by the Document node in the DOM tree, which isn't focusable.
582    // Check instead if the frame's selection controller is focused
583    if (focusedElement == m_renderer->node()
584        || (roleValue() == WebAreaRole && document->frame()->selection()->isFocusedAndActive()))
585        return true;
586
587    return false;
588}
589
590bool AccessibilityRenderObject::isSelected() const
591{
592    if (!m_renderer)
593        return false;
594
595    Node* node = m_renderer->node();
596    if (!node)
597        return false;
598
599    const AtomicString& ariaSelected = getAttribute(aria_selectedAttr);
600    if (equalIgnoringCase(ariaSelected, "true"))
601        return true;
602
603    if (isTabItem() && isTabItemSelected())
604        return true;
605
606    return false;
607}
608
609//
610// Check whether certain properties can be modified.
611//
612
613bool AccessibilityRenderObject::canSetValueAttribute() const
614{
615    if (equalIgnoringCase(getAttribute(aria_readonlyAttr), "true"))
616        return false;
617
618    if (isProgressIndicator() || isSlider())
619        return true;
620
621    if (isTextControl() && !isNativeTextControl())
622        return true;
623
624    // Any node could be contenteditable, so isReadOnly should be relied upon
625    // for this information for all elements.
626    return !isReadOnly();
627}
628
629//
630// Whether objects are ignored, i.e. not included in the tree.
631//
632
633AccessibilityObjectInclusion AccessibilityRenderObject::defaultObjectInclusion() const
634{
635    // The following cases can apply to any element that's a subclass of AccessibilityRenderObject.
636
637    if (!m_renderer)
638        return IgnoreObject;
639
640    if (m_renderer->style()->visibility() != VISIBLE) {
641        // aria-hidden is meant to override visibility as the determinant in AX hierarchy inclusion.
642        if (equalIgnoringCase(getAttribute(aria_hiddenAttr), "false"))
643            return DefaultBehavior;
644
645        return IgnoreObject;
646    }
647
648    return AccessibilityObject::defaultObjectInclusion();
649}
650
651bool AccessibilityRenderObject::computeAccessibilityIsIgnored() const
652{
653#ifndef NDEBUG
654    ASSERT(m_initialized);
655#endif
656
657    // Check first if any of the common reasons cause this element to be ignored.
658    // Then process other use cases that need to be applied to all the various roles
659    // that AccessibilityRenderObjects take on.
660    AccessibilityObjectInclusion decision = defaultObjectInclusion();
661    if (decision == IncludeObject)
662        return false;
663    if (decision == IgnoreObject)
664        return true;
665
666    // If this element is within a parent that cannot have children, it should not be exposed.
667    if (isDescendantOfBarrenParent())
668        return true;
669
670    if (roleValue() == IgnoredRole)
671        return true;
672
673    if (roleValue() == PresentationalRole || inheritsPresentationalRole())
674        return true;
675
676    // An ARIA tree can only have tree items and static text as children.
677    if (!isAllowedChildOfTree())
678        return true;
679
680    // TODO: we should refactor this - but right now this is necessary to make
681    // sure scroll areas stay in the tree.
682    if (isAttachment())
683        return false;
684
685    // ignore popup menu items because AppKit does
686    for (RenderObject* parent = m_renderer->parent(); parent; parent = parent->parent()) {
687        if (parent->isBoxModelObject() && toRenderBoxModelObject(parent)->isMenuList())
688            return true;
689    }
690
691    // find out if this element is inside of a label element.
692    // if so, it may be ignored because it's the label for a checkbox or radio button
693    AccessibilityObject* controlObject = correspondingControlForLabelElement();
694    if (controlObject && !controlObject->exposesTitleUIElement() && controlObject->isCheckboxOrRadio())
695        return true;
696
697    // NOTE: BRs always have text boxes now, so the text box check here can be removed
698    if (m_renderer->isText()) {
699        // static text beneath MenuItems and MenuButtons are just reported along with the menu item, so it's ignored on an individual level
700        AccessibilityObject* parent = parentObjectUnignored();
701        if (parent && (parent->ariaRoleAttribute() == MenuItemRole || parent->ariaRoleAttribute() == MenuButtonRole))
702            return true;
703        RenderText* renderText = toRenderText(m_renderer);
704        if (m_renderer->isBR() || !renderText->firstTextBox())
705            return true;
706
707        // static text beneath TextControls is reported along with the text control text so it's ignored.
708        for (AccessibilityObject* parent = parentObject(); parent; parent = parent->parentObject()) {
709            if (parent->roleValue() == TextFieldRole)
710                return true;
711        }
712
713        // text elements that are just empty whitespace should not be returned
714        return renderText->text().impl()->containsOnlyWhitespace();
715    }
716
717    if (isHeading())
718        return false;
719
720    if (isLink())
721        return false;
722
723    // all controls are accessible
724    if (isControl())
725        return false;
726
727    if (ariaRoleAttribute() != UnknownRole)
728        return false;
729
730    // don't ignore labels, because they serve as TitleUIElements
731    Node* node = m_renderer->node();
732    if (node && isHTMLLabelElement(node))
733        return false;
734
735    // Anything that is content editable should not be ignored.
736    // However, one cannot just call node->rendererIsEditable() since that will ask if its parents
737    // are also editable. Only the top level content editable region should be exposed.
738    if (hasContentEditableAttributeSet())
739        return false;
740
741    // List items play an important role in defining the structure of lists. They should not be ignored.
742    if (roleValue() == ListItemRole)
743        return false;
744
745    // if this element has aria attributes on it, it should not be ignored.
746    if (supportsARIAAttributes())
747        return false;
748
749    // <span> tags are inline tags and not meant to convey information if they have no other aria
750    // information on them. If we don't ignore them, they may emit signals expected to come from
751    // their parent. In addition, because included spans are GroupRole objects, and GroupRole
752    // objects are often containers with meaningful information, the inclusion of a span can have
753    // the side effect of causing the immediate parent accessible to be ignored. This is especially
754    // problematic for platforms which have distinct roles for textual block elements.
755    if (node && node->hasTagName(spanTag))
756        return true;
757
758    if (m_renderer->isBlockFlow() && m_renderer->childrenInline() && !canSetFocusAttribute())
759        return !toRenderBlock(m_renderer)->firstLineBox() && !mouseButtonListener();
760
761    // ignore images seemingly used as spacers
762    if (isImage()) {
763
764        // If the image can take focus, it should not be ignored, lest the user not be able to interact with something important.
765        if (canSetFocusAttribute())
766            return false;
767
768        if (node && node->isElementNode()) {
769            Element* elt = toElement(node);
770            const AtomicString& alt = elt->getAttribute(altAttr);
771            // don't ignore an image that has an alt tag
772            if (!alt.string().containsOnlyWhitespace())
773                return false;
774            // informal standard is to ignore images with zero-length alt strings
775            if (!alt.isNull())
776                return true;
777        }
778
779        if (isNativeImage()) {
780            // check for one-dimensional image
781            RenderImage* image = toRenderImage(m_renderer);
782            if (image->height() <= 1 || image->width() <= 1)
783                return true;
784
785            // check whether rendered image was stretched from one-dimensional file image
786            if (image->cachedImage()) {
787                LayoutSize imageSize = image->cachedImage()->imageSizeForRenderer(m_renderer, image->view()->zoomFactor());
788                return imageSize.height() <= 1 || imageSize.width() <= 1;
789            }
790        }
791        return false;
792    }
793
794    if (isCanvas()) {
795        if (canvasHasFallbackContent())
796            return false;
797        RenderHTMLCanvas* canvas = toRenderHTMLCanvas(m_renderer);
798        if (canvas->height() <= 1 || canvas->width() <= 1)
799            return true;
800        // Otherwise fall through; use presence of help text, title, or description to decide.
801    }
802
803    if (isWebArea() || isSeamlessWebArea() || m_renderer->isListMarker())
804        return false;
805
806    // Using the help text, title or accessibility description (so we
807    // check if there's some kind of accessible name for the element)
808    // to decide an element's visibility is not as definitive as
809    // previous checks, so this should remain as one of the last.
810    //
811    // These checks are simplified in the interest of execution speed;
812    // for example, any element having an alt attribute will make it
813    // not ignored, rather than just images.
814    if (!getAttribute(aria_helpAttr).isEmpty() || !getAttribute(aria_describedbyAttr).isEmpty() || !getAttribute(altAttr).isEmpty() || !getAttribute(titleAttr).isEmpty())
815        return false;
816
817    // Don't ignore generic focusable elements like <div tabindex=0>
818    // unless they're completely empty, with no children.
819    if (isGenericFocusableElement() && node->firstChild())
820        return false;
821
822    if (!ariaAccessibilityDescription().isEmpty())
823        return false;
824
825    // By default, objects should be ignored so that the AX hierarchy is not
826    // filled with unnecessary items.
827    return true;
828}
829
830//
831// Properties of static elements.
832//
833
834const AtomicString& AccessibilityRenderObject::accessKey() const
835{
836    Node* node = m_renderer->node();
837    if (!node)
838        return nullAtom;
839    if (!node->isElementNode())
840        return nullAtom;
841    return toElement(node)->getAttribute(accesskeyAttr);
842}
843
844AccessibilityObject* AccessibilityRenderObject::correspondingControlForLabelElement() const
845{
846    HTMLLabelElement* labelElement = labelElementContainer();
847    if (!labelElement)
848        return 0;
849
850    HTMLElement* correspondingControl = labelElement->control();
851    if (!correspondingControl)
852        return 0;
853
854    // Make sure the corresponding control isn't a descendant of this label
855    // that's in the middle of being destroyed.
856    if (correspondingControl->renderer() && !correspondingControl->renderer()->parent())
857        return 0;
858
859    return axObjectCache()->getOrCreate(correspondingControl);
860}
861
862bool AccessibilityRenderObject::exposesTitleUIElement() const
863{
864    if (!isControl())
865        return false;
866
867    // If this control is ignored (because it's invisible),
868    // then the label needs to be exposed so it can be visible to accessibility.
869    if (accessibilityIsIgnored())
870        return true;
871
872    // Checkboxes and radio buttons use the text of their title ui element as their own AXTitle.
873    // This code controls whether the title ui element should appear in the AX tree (usually, no).
874    // It should appear if the control already has a label (which will be used as the AXTitle instead).
875    if (isCheckboxOrRadio())
876        return hasTextAlternative();
877
878    // When controls have their own descriptions, the title element should be ignored.
879    if (hasTextAlternative())
880        return false;
881
882    return true;
883}
884
885AccessibilityOrientation AccessibilityRenderObject::orientation() const
886{
887    const AtomicString& ariaOrientation = getAttribute(aria_orientationAttr);
888    if (equalIgnoringCase(ariaOrientation, "horizontal"))
889        return AccessibilityOrientationHorizontal;
890    if (equalIgnoringCase(ariaOrientation, "vertical"))
891        return AccessibilityOrientationVertical;
892
893    return AccessibilityObject::orientation();
894}
895
896String AccessibilityRenderObject::text() const
897{
898    if (isPasswordField())
899        return String();
900
901    return AccessibilityNodeObject::text();
902}
903
904int AccessibilityRenderObject::textLength() const
905{
906    ASSERT(isTextControl());
907
908    if (isPasswordField())
909        return -1; // need to return something distinct from 0
910
911    return text().length();
912}
913
914AccessibilityObject* AccessibilityRenderObject::titleUIElement() const
915{
916    if (!m_renderer)
917        return 0;
918
919    // if isFieldset is true, the renderer is guaranteed to be a RenderFieldset
920    if (isFieldset())
921        return axObjectCache()->getOrCreate(toRenderFieldset(m_renderer)->findLegend(RenderFieldset::IncludeFloatingOrOutOfFlow));
922
923    Node* node = m_renderer->node();
924    if (!node || !node->isElementNode())
925        return 0;
926    HTMLLabelElement* label = labelForElement(toElement(node));
927    if (label && label->renderer())
928        return axObjectCache()->getOrCreate(label);
929
930    return 0;
931}
932
933KURL AccessibilityRenderObject::url() const
934{
935    if (isAnchor() && isHTMLAnchorElement(m_renderer->node())) {
936        if (HTMLAnchorElement* anchor = toHTMLAnchorElement(anchorElement()))
937            return anchor->href();
938    }
939
940    if (isWebArea())
941        return m_renderer->document()->url();
942
943    if (isImage() && m_renderer->node() && m_renderer->node()->hasTagName(imgTag))
944        return toHTMLImageElement(m_renderer->node())->src();
945
946    if (isInputImage())
947        return toHTMLInputElement(m_renderer->node())->src();
948
949    return KURL();
950}
951
952//
953// Properties of interactive elements.
954//
955
956String AccessibilityRenderObject::actionVerb() const
957{
958    switch (roleValue()) {
959    case ButtonRole:
960    case ToggleButtonRole:
961        return AXButtonActionVerb();
962    case TextFieldRole:
963    case TextAreaRole:
964        return AXTextFieldActionVerb();
965    case RadioButtonRole:
966        return AXRadioButtonActionVerb();
967    case CheckBoxRole:
968        return isChecked() ? AXCheckedCheckBoxActionVerb() : AXUncheckedCheckBoxActionVerb();
969    case LinkRole:
970    case WebCoreLinkRole:
971        return AXLinkActionVerb();
972    default:
973        return emptyString();
974    }
975}
976
977void AccessibilityRenderObject::selectedChildren(AccessibilityChildrenVector& result)
978{
979    ASSERT(result.isEmpty());
980
981    // only listboxes should be asked for their selected children.
982    AccessibilityRole role = roleValue();
983    if (role == ListBoxRole) // native list boxes would be AccessibilityListBoxes, so only check for aria list boxes
984        ariaListboxSelectedChildren(result);
985    else if (role == TreeRole || role == TreeGridRole || role == TableRole)
986        ariaSelectedRows(result);
987}
988
989String AccessibilityRenderObject::stringValue() const
990{
991    if (!m_renderer)
992        return String();
993
994    if (isPasswordField())
995        return String();
996
997    RenderBoxModelObject* cssBox = renderBoxModelObject();
998
999    if (ariaRoleAttribute() == StaticTextRole) {
1000        String staticText = text();
1001        if (!staticText.length())
1002            staticText = textUnderElement();
1003        return staticText;
1004    }
1005
1006    if (m_renderer->isText())
1007        return textUnderElement();
1008
1009    if (cssBox && cssBox->isMenuList()) {
1010        // RenderMenuList will go straight to the text() of its selected item.
1011        // This has to be overridden in the case where the selected item has an ARIA label.
1012        HTMLSelectElement* selectElement = toHTMLSelectElement(m_renderer->node());
1013        int selectedIndex = selectElement->selectedIndex();
1014        const Vector<HTMLElement*> listItems = selectElement->listItems();
1015        if (selectedIndex >= 0 && static_cast<size_t>(selectedIndex) < listItems.size()) {
1016            const AtomicString& overriddenDescription = listItems[selectedIndex]->fastGetAttribute(aria_labelAttr);
1017            if (!overriddenDescription.isNull())
1018                return overriddenDescription;
1019        }
1020        return toRenderMenuList(m_renderer)->text();
1021    }
1022
1023    if (m_renderer->isListMarker())
1024        return toRenderListMarker(m_renderer)->text();
1025
1026    if (isWebArea()) {
1027        // FIXME: Why would a renderer exist when the Document isn't attached to a frame?
1028        if (m_renderer->frame())
1029            return String();
1030
1031        ASSERT_NOT_REACHED();
1032    }
1033
1034    if (isTextControl())
1035        return text();
1036
1037    if (m_renderer->isFileUploadControl())
1038        return toRenderFileUploadControl(m_renderer)->fileTextValue();
1039
1040    // FIXME: We might need to implement a value here for more types
1041    // FIXME: It would be better not to advertise a value at all for the types for which we don't implement one;
1042    // this would require subclassing or making accessibilityAttributeNames do something other than return a
1043    // single static array.
1044    return String();
1045}
1046
1047//
1048// ARIA attributes.
1049//
1050
1051AccessibilityObject* AccessibilityRenderObject::activeDescendant() const
1052{
1053    if (!m_renderer)
1054        return 0;
1055
1056    if (m_renderer->node() && !m_renderer->node()->isElementNode())
1057        return 0;
1058    Element* element = toElement(m_renderer->node());
1059
1060    const AtomicString& activeDescendantAttrStr = element->getAttribute(aria_activedescendantAttr);
1061    if (activeDescendantAttrStr.isNull() || activeDescendantAttrStr.isEmpty())
1062        return 0;
1063
1064    Element* target = element->treeScope()->getElementById(activeDescendantAttrStr);
1065    if (!target)
1066        return 0;
1067
1068    AccessibilityObject* obj = axObjectCache()->getOrCreate(target);
1069    if (obj && obj->isAccessibilityRenderObject())
1070    // an activedescendant is only useful if it has a renderer, because that's what's needed to post the notification
1071        return obj;
1072    return 0;
1073}
1074
1075void AccessibilityRenderObject::ariaFlowToElements(AccessibilityChildrenVector& flowTo) const
1076{
1077    Vector<Element*> elements;
1078    elementsFromAttribute(elements, aria_flowtoAttr);
1079
1080    AXObjectCache* cache = axObjectCache();
1081    unsigned count = elements.size();
1082    for (unsigned k = 0; k < count; ++k) {
1083        Element* element = elements[k];
1084        AccessibilityObject* flowToElement = cache->getOrCreate(element);
1085        if (flowToElement)
1086            flowTo.append(flowToElement);
1087    }
1088}
1089
1090bool AccessibilityRenderObject::ariaHasPopup() const
1091{
1092    return elementAttributeValue(aria_haspopupAttr);
1093}
1094
1095bool AccessibilityRenderObject::ariaRoleHasPresentationalChildren() const
1096{
1097    switch (m_ariaRole) {
1098    case ButtonRole:
1099    case SliderRole:
1100    case ImageRole:
1101    case ProgressIndicatorRole:
1102    case SpinButtonRole:
1103    // case SeparatorRole:
1104        return true;
1105    default:
1106        return false;
1107    }
1108}
1109
1110bool AccessibilityRenderObject::isPresentationalChildOfAriaRole() const
1111{
1112    // Walk the parent chain looking for a parent that has presentational children
1113    AccessibilityObject* parent;
1114    for (parent = parentObject(); parent && !parent->ariaRoleHasPresentationalChildren(); parent = parent->parentObject())
1115    { }
1116
1117    return parent;
1118}
1119
1120bool AccessibilityRenderObject::shouldFocusActiveDescendant() const
1121{
1122    switch (ariaRoleAttribute()) {
1123    case GroupRole:
1124    case ListBoxRole:
1125    case MenuRole:
1126    case MenuBarRole:
1127    case RadioGroupRole:
1128    case RowRole:
1129    case PopUpButtonRole:
1130    case ProgressIndicatorRole:
1131    case ToolbarRole:
1132    case OutlineRole:
1133    case TreeRole:
1134    case GridRole:
1135    /* FIXME: replace these with actual roles when they are added to AccessibilityRole
1136    composite
1137    alert
1138    alertdialog
1139    status
1140    timer
1141    */
1142        return true;
1143    default:
1144        return false;
1145    }
1146}
1147
1148bool AccessibilityRenderObject::supportsARIADragging() const
1149{
1150    const AtomicString& grabbed = getAttribute(aria_grabbedAttr);
1151    return equalIgnoringCase(grabbed, "true") || equalIgnoringCase(grabbed, "false");
1152}
1153
1154bool AccessibilityRenderObject::supportsARIADropping() const
1155{
1156    const AtomicString& dropEffect = getAttribute(aria_dropeffectAttr);
1157    return !dropEffect.isEmpty();
1158}
1159
1160bool AccessibilityRenderObject::supportsARIAFlowTo() const
1161{
1162    return !getAttribute(aria_flowtoAttr).isEmpty();
1163}
1164
1165bool AccessibilityRenderObject::supportsARIAOwns() const
1166{
1167    if (!m_renderer)
1168        return false;
1169    const AtomicString& ariaOwns = getAttribute(aria_ownsAttr);
1170
1171    return !ariaOwns.isEmpty();
1172}
1173
1174//
1175// ARIA live-region features.
1176//
1177
1178const AtomicString& AccessibilityRenderObject::ariaLiveRegionStatus() const
1179{
1180    DEFINE_STATIC_LOCAL(const AtomicString, liveRegionStatusAssertive, ("assertive", AtomicString::ConstructFromLiteral));
1181    DEFINE_STATIC_LOCAL(const AtomicString, liveRegionStatusPolite, ("polite", AtomicString::ConstructFromLiteral));
1182    DEFINE_STATIC_LOCAL(const AtomicString, liveRegionStatusOff, ("off", AtomicString::ConstructFromLiteral));
1183
1184    const AtomicString& liveRegionStatus = getAttribute(aria_liveAttr);
1185    // These roles have implicit live region status.
1186    if (liveRegionStatus.isEmpty()) {
1187        switch (roleValue()) {
1188        case ApplicationAlertDialogRole:
1189        case ApplicationAlertRole:
1190            return liveRegionStatusAssertive;
1191        case ApplicationLogRole:
1192        case ApplicationStatusRole:
1193            return liveRegionStatusPolite;
1194        case ApplicationTimerRole:
1195        case ApplicationMarqueeRole:
1196            return liveRegionStatusOff;
1197        default:
1198            break;
1199        }
1200    }
1201
1202    return liveRegionStatus;
1203}
1204
1205const AtomicString& AccessibilityRenderObject::ariaLiveRegionRelevant() const
1206{
1207    DEFINE_STATIC_LOCAL(const AtomicString, defaultLiveRegionRelevant, ("additions text", AtomicString::ConstructFromLiteral));
1208    const AtomicString& relevant = getAttribute(aria_relevantAttr);
1209
1210    // Default aria-relevant = "additions text".
1211    if (relevant.isEmpty())
1212        return defaultLiveRegionRelevant;
1213
1214    return relevant;
1215}
1216
1217bool AccessibilityRenderObject::ariaLiveRegionAtomic() const
1218{
1219    return elementAttributeValue(aria_atomicAttr);
1220}
1221
1222bool AccessibilityRenderObject::ariaLiveRegionBusy() const
1223{
1224    return elementAttributeValue(aria_busyAttr);
1225}
1226
1227//
1228// Accessibility Text.
1229//
1230
1231String AccessibilityRenderObject::textUnderElement() const
1232{
1233    if (!m_renderer)
1234        return String();
1235
1236    if (m_renderer->isFileUploadControl())
1237        return toRenderFileUploadControl(m_renderer)->buttonValue();
1238
1239    if (m_renderer->isText()) {
1240        // If possible, use a text iterator to get the text, so that whitespace
1241        // is handled consistently.
1242        if (Node* node = this->node()) {
1243            if (Frame* frame = node->document()->frame()) {
1244                // catch stale WebCoreAXObject (see <rdar://problem/3960196>)
1245                if (frame->document() != node->document())
1246                    return String();
1247
1248                return plainText(rangeOfContents(node).get(), textIteratorBehaviorForTextRange());
1249            }
1250        }
1251
1252        // Sometimes text fragments don't have Nodes associated with them (like when
1253        // CSS content is used to insert text or when a RenderCounter is used.)
1254        RenderText* renderTextObject = toRenderText(m_renderer);
1255        if (renderTextObject->isTextFragment())
1256            return String(static_cast<RenderTextFragment*>(m_renderer)->contentString());
1257        else
1258            return String(renderTextObject->text());
1259    }
1260
1261    return AccessibilityNodeObject::textUnderElement();
1262}
1263
1264//
1265// Accessibility Text - (To be deprecated).
1266//
1267
1268String AccessibilityRenderObject::helpText() const
1269{
1270    if (!m_renderer)
1271        return String();
1272
1273    const AtomicString& ariaHelp = getAttribute(aria_helpAttr);
1274    if (!ariaHelp.isEmpty())
1275        return ariaHelp;
1276
1277    String describedBy = ariaDescribedByAttribute();
1278    if (!describedBy.isEmpty())
1279        return describedBy;
1280
1281    String description = accessibilityDescription();
1282    for (RenderObject* curr = m_renderer; curr; curr = curr->parent()) {
1283        if (curr->node() && curr->node()->isHTMLElement()) {
1284            const AtomicString& summary = toElement(curr->node())->getAttribute(summaryAttr);
1285            if (!summary.isEmpty())
1286                return summary;
1287
1288            // The title attribute should be used as help text unless it is already being used as descriptive text.
1289            const AtomicString& title = toElement(curr->node())->getAttribute(titleAttr);
1290            if (!title.isEmpty() && description != title)
1291                return title;
1292        }
1293
1294        // Only take help text from an ancestor element if its a group or an unknown role. If help was
1295        // added to those kinds of elements, it is likely it was meant for a child element.
1296        AccessibilityObject* axObj = axObjectCache()->getOrCreate(curr);
1297        if (axObj) {
1298            AccessibilityRole role = axObj->roleValue();
1299            if (role != GroupRole && role != UnknownRole)
1300                break;
1301        }
1302    }
1303
1304    return String();
1305}
1306
1307//
1308// Position and size.
1309//
1310
1311void AccessibilityRenderObject::checkCachedElementRect() const
1312{
1313    if (m_cachedElementRectDirty)
1314        return;
1315
1316    if (!m_renderer)
1317        return;
1318
1319    if (!m_renderer->isBox())
1320        return;
1321
1322    bool dirty = false;
1323    RenderBox* box = toRenderBox(m_renderer);
1324    if (box->frameRect() != m_cachedFrameRect)
1325        dirty = true;
1326
1327    if (box->canBeScrolledAndHasScrollableArea()) {
1328        ScrollableArea* scrollableArea = box->layer();
1329        if (scrollableArea && scrollableArea->scrollPosition() != m_cachedScrollPosition)
1330            dirty = true;
1331    }
1332
1333    if (dirty)
1334        markCachedElementRectDirty();
1335}
1336
1337void AccessibilityRenderObject::updateCachedElementRect() const
1338{
1339    if (!m_cachedElementRectDirty)
1340        return;
1341
1342    if (!m_renderer)
1343        return;
1344
1345    if (!m_renderer->isBox())
1346        return;
1347
1348    RenderBox* box = toRenderBox(m_renderer);
1349    m_cachedFrameRect = box->frameRect();
1350
1351    if (box->canBeScrolledAndHasScrollableArea()) {
1352        ScrollableArea* scrollableArea = box->layer();
1353        if (scrollableArea)
1354            m_cachedScrollPosition = scrollableArea->scrollPosition();
1355    }
1356
1357    m_cachedElementRect = computeElementRect();
1358    m_cachedElementRectDirty = false;
1359}
1360
1361void AccessibilityRenderObject::markCachedElementRectDirty() const
1362{
1363    if (m_cachedElementRectDirty)
1364        return;
1365
1366    // Marks children recursively, if this element changed.
1367    m_cachedElementRectDirty = true;
1368    for (AccessibilityObject* child = firstChild(); child; child = child->nextSibling())
1369        child->markCachedElementRectDirty();
1370}
1371
1372IntPoint AccessibilityRenderObject::clickPoint()
1373{
1374    // Headings are usually much wider than their textual content. If the mid point is used, often it can be wrong.
1375    if (isHeading() && children().size() == 1)
1376        return children()[0]->clickPoint();
1377
1378    // use the default position unless this is an editable web area, in which case we use the selection bounds.
1379    if (!isWebArea() || isReadOnly())
1380        return AccessibilityObject::clickPoint();
1381
1382    LayoutRect bounds = elementRect();
1383    return IntPoint(bounds.x() + (bounds.width() / 2), bounds.y() - (bounds.height() / 2));
1384}
1385
1386//
1387// Hit testing.
1388//
1389
1390AccessibilityObject* AccessibilityRenderObject::accessibilityHitTest(const IntPoint& point) const
1391{
1392    if (!m_renderer || !m_renderer->hasLayer())
1393        return 0;
1394
1395    RenderLayer* layer = toRenderBox(m_renderer)->layer();
1396
1397    HitTestRequest request(HitTestRequest::ReadOnly | HitTestRequest::Active);
1398    HitTestResult hitTestResult = HitTestResult(point);
1399    layer->hitTest(request, hitTestResult);
1400    if (!hitTestResult.innerNode())
1401        return 0;
1402    Node* node = hitTestResult.innerNode()->deprecatedShadowAncestorNode();
1403
1404    if (isHTMLAreaElement(node))
1405        return accessibilityImageMapHitTest(toHTMLAreaElement(node), point);
1406
1407    if (node->hasTagName(optionTag))
1408        node = toHTMLOptionElement(node)->ownerSelectElement();
1409
1410    RenderObject* obj = node->renderer();
1411    if (!obj)
1412        return 0;
1413
1414    AccessibilityObject* result = obj->document()->axObjectCache()->getOrCreate(obj);
1415    result->updateChildrenIfNecessary();
1416
1417    // Allow the element to perform any hit-testing it might need to do to reach non-render children.
1418    result = result->elementAccessibilityHitTest(point);
1419
1420    if (result && result->accessibilityIsIgnored()) {
1421        // If this element is the label of a control, a hit test should return the control.
1422        if (result->isAccessibilityRenderObject()) {
1423            AccessibilityObject* controlObject = static_cast<AccessibilityRenderObject*>(result)->correspondingControlForLabelElement();
1424            if (controlObject && !controlObject->exposesTitleUIElement())
1425                return controlObject;
1426        }
1427
1428        result = result->parentObjectUnignored();
1429    }
1430
1431    return result;
1432}
1433
1434AccessibilityObject* AccessibilityRenderObject::elementAccessibilityHitTest(const IntPoint& point) const
1435{
1436    if (isSVGImage())
1437        return remoteSVGElementHitTest(point);
1438
1439    return AccessibilityObject::elementAccessibilityHitTest(point);
1440}
1441
1442//
1443// High-level accessibility tree access.
1444//
1445
1446AccessibilityObject* AccessibilityRenderObject::parentObject() const
1447{
1448    if (!m_renderer)
1449        return 0;
1450
1451    if (ariaRoleAttribute() == MenuBarRole)
1452        return axObjectCache()->getOrCreate(m_renderer->parent());
1453
1454    // menuButton and its corresponding menu are DOM siblings, but Accessibility needs them to be parent/child
1455    if (ariaRoleAttribute() == MenuRole) {
1456        AccessibilityObject* parent = menuButtonForMenu();
1457        if (parent)
1458            return parent;
1459    }
1460
1461    RenderObject* parentObj = renderParentObject();
1462    if (parentObj)
1463        return axObjectCache()->getOrCreate(parentObj);
1464
1465    // WebArea's parent should be the scroll view containing it.
1466    if (isWebArea() || isSeamlessWebArea())
1467        return axObjectCache()->getOrCreate(m_renderer->frame()->view());
1468
1469    return 0;
1470}
1471
1472AccessibilityObject* AccessibilityRenderObject::parentObjectIfExists() const
1473{
1474    // WebArea's parent should be the scroll view containing it.
1475    if (isWebArea() || isSeamlessWebArea())
1476        return axObjectCache()->get(m_renderer->frame()->view());
1477
1478    return axObjectCache()->get(renderParentObject());
1479}
1480
1481//
1482// Low-level accessibility tree exploration, only for use within the accessibility module.
1483//
1484
1485AccessibilityObject* AccessibilityRenderObject::firstChild() const
1486{
1487    if (!m_renderer)
1488        return 0;
1489
1490    RenderObject* firstChild = firstChildConsideringContinuation(m_renderer);
1491
1492    if (!firstChild)
1493        return 0;
1494
1495    return axObjectCache()->getOrCreate(firstChild);
1496}
1497
1498AccessibilityObject* AccessibilityRenderObject::nextSibling() const
1499{
1500    if (!m_renderer)
1501        return 0;
1502
1503    RenderObject* nextSibling = 0;
1504
1505    // Case 1: node is a block and has an inline continuation. Next sibling is the inline continuation's
1506    // first child.
1507    RenderInline* inlineContinuation;
1508    if (m_renderer->isRenderBlock() && (inlineContinuation = toRenderBlock(m_renderer)->inlineElementContinuation()))
1509        nextSibling = firstChildConsideringContinuation(inlineContinuation);
1510
1511    // Case 2: Anonymous block parent of the start of a continuation - skip all the way to
1512    // after the parent of the end, since everything in between will be linked up via the continuation.
1513    else if (m_renderer->isAnonymousBlock() && lastChildHasContinuation(m_renderer)) {
1514        RenderObject* lastParent = endOfContinuations(m_renderer->lastChild())->parent();
1515        while (lastChildHasContinuation(lastParent))
1516            lastParent = endOfContinuations(lastParent->lastChild())->parent();
1517        nextSibling = lastParent->nextSibling();
1518    }
1519
1520    // Case 3: node has an actual next sibling
1521    else if (RenderObject* ns = m_renderer->nextSibling())
1522        nextSibling = ns;
1523
1524    // Case 4: node is an inline with a continuation. Next sibling is the next sibling of the end
1525    // of the continuation chain.
1526    else if (isInlineWithContinuation(m_renderer))
1527        nextSibling = endOfContinuations(m_renderer)->nextSibling();
1528
1529    // Case 5: node has no next sibling, and its parent is an inline with a continuation.
1530    else if (isInlineWithContinuation(m_renderer->parent())) {
1531        RenderObject* continuation = toRenderInline(m_renderer->parent())->continuation();
1532
1533        // Case 5a: continuation is a block - in this case the block itself is the next sibling.
1534        if (continuation->isRenderBlock())
1535            nextSibling = continuation;
1536        // Case 5b: continuation is an inline - in this case the inline's first child is the next sibling
1537        else
1538            nextSibling = firstChildConsideringContinuation(continuation);
1539    }
1540
1541    if (!nextSibling)
1542        return 0;
1543
1544    return axObjectCache()->getOrCreate(nextSibling);
1545}
1546
1547void AccessibilityRenderObject::addChildren()
1548{
1549    // If the need to add more children in addition to existing children arises,
1550    // childrenChanged should have been called, leaving the object with no children.
1551    ASSERT(!m_haveChildren);
1552
1553    m_haveChildren = true;
1554
1555    if (!canHaveChildren())
1556        return;
1557
1558    for (RefPtr<AccessibilityObject> obj = firstChild(); obj; obj = obj->nextSibling())
1559        addChild(obj.get());
1560
1561    addHiddenChildren();
1562    addAttachmentChildren();
1563    addImageMapChildren();
1564    addTextFieldChildren();
1565    addCanvasChildren();
1566    addRemoteSVGChildren();
1567}
1568
1569bool AccessibilityRenderObject::canHaveChildren() const
1570{
1571    if (!m_renderer)
1572        return false;
1573
1574    return AccessibilityNodeObject::canHaveChildren();
1575}
1576
1577void AccessibilityRenderObject::updateChildrenIfNecessary()
1578{
1579    if (needsToUpdateChildren())
1580        clearChildren();
1581
1582    AccessibilityObject::updateChildrenIfNecessary();
1583}
1584
1585void AccessibilityRenderObject::clearChildren()
1586{
1587    AccessibilityObject::clearChildren();
1588    m_childrenDirty = false;
1589}
1590
1591AccessibilityObject* AccessibilityRenderObject::observableObject() const
1592{
1593    // Find the object going up the parent chain that is used in accessibility to monitor certain notifications.
1594    for (RenderObject* renderer = m_renderer; renderer && renderer->node(); renderer = renderer->parent()) {
1595        if (renderObjectIsObservable(renderer))
1596            return axObjectCache()->getOrCreate(renderer);
1597    }
1598
1599    return 0;
1600}
1601
1602//
1603// Properties of the object's owning document or page.
1604//
1605
1606double AccessibilityRenderObject::estimatedLoadingProgress() const
1607{
1608    if (!m_renderer)
1609        return 0;
1610
1611    if (isLoaded())
1612        return 1.0;
1613
1614    Page* page = m_renderer->document()->page();
1615    if (!page)
1616        return 0;
1617
1618    return page->progress()->estimatedProgress();
1619}
1620
1621//
1622// DOM and Render tree access.
1623//
1624
1625Node* AccessibilityRenderObject::node() const
1626{
1627    return m_renderer ? m_renderer->node() : 0;
1628}
1629
1630Document* AccessibilityRenderObject::document() const
1631{
1632    if (!m_renderer)
1633        return 0;
1634    return m_renderer->document();
1635}
1636
1637FrameView* AccessibilityRenderObject::documentFrameView() const
1638{
1639    if (!m_renderer || !m_renderer->document())
1640        return 0;
1641
1642    // this is the RenderObject's Document's Frame's FrameView
1643    return m_renderer->document()->view();
1644}
1645
1646Element* AccessibilityRenderObject::anchorElement() const
1647{
1648    if (!m_renderer)
1649        return 0;
1650
1651    AXObjectCache* cache = axObjectCache();
1652    RenderObject* currRenderer;
1653
1654    // Search up the render tree for a RenderObject with a DOM node.  Defer to an earlier continuation, though.
1655    for (currRenderer = m_renderer; currRenderer && !currRenderer->node(); currRenderer = currRenderer->parent()) {
1656        if (currRenderer->isAnonymousBlock()) {
1657            RenderObject* continuation = toRenderBlock(currRenderer)->continuation();
1658            if (continuation)
1659                return cache->getOrCreate(continuation)->anchorElement();
1660        }
1661    }
1662
1663    // bail if none found
1664    if (!currRenderer)
1665        return 0;
1666
1667    // search up the DOM tree for an anchor element
1668    // NOTE: this assumes that any non-image with an anchor is an HTMLAnchorElement
1669    Node* node = currRenderer->node();
1670    for ( ; node; node = node->parentNode()) {
1671        if (isHTMLAnchorElement(node) || (node->renderer() && cache->getOrCreate(node->renderer())->isAnchor()))
1672            return toElement(node);
1673    }
1674
1675    return 0;
1676}
1677
1678Widget* AccessibilityRenderObject::widgetForAttachmentView() const
1679{
1680    if (!isAttachment())
1681        return 0;
1682    return toRenderWidget(m_renderer)->widget();
1683}
1684
1685//
1686// Selected text.
1687//
1688
1689PlainTextRange AccessibilityRenderObject::selectedTextRange() const
1690{
1691    ASSERT(isTextControl());
1692
1693    if (isPasswordField())
1694        return PlainTextRange();
1695
1696    AccessibilityRole ariaRole = ariaRoleAttribute();
1697    if (isNativeTextControl() && ariaRole == UnknownRole) {
1698        HTMLTextFormControlElement* textControl = toRenderTextControl(m_renderer)->textFormControlElement();
1699        return PlainTextRange(textControl->selectionStart(), textControl->selectionEnd() - textControl->selectionStart());
1700    }
1701
1702    if (ariaRole == UnknownRole)
1703        return PlainTextRange();
1704
1705    return ariaSelectedTextRange();
1706}
1707
1708VisibleSelection AccessibilityRenderObject::selection() const
1709{
1710    return m_renderer->frame()->selection()->selection();
1711}
1712
1713String AccessibilityRenderObject::selectedText() const
1714{
1715    ASSERT(isTextControl());
1716
1717    if (isPasswordField())
1718        return String(); // need to return something distinct from empty string
1719
1720    if (isNativeTextControl()) {
1721        HTMLTextFormControlElement* textControl = toRenderTextControl(m_renderer)->textFormControlElement();
1722        return textControl->selectedText();
1723    }
1724
1725    if (ariaRoleAttribute() == UnknownRole)
1726        return String();
1727
1728    return stringForRange(ariaSelectedTextRange());
1729}
1730
1731//
1732// Modify or take an action on an object.
1733//
1734
1735void AccessibilityRenderObject::setFocused(bool on)
1736{
1737    if (!canSetFocusAttribute())
1738        return;
1739
1740    Document* document = this->document();
1741    if (!on)
1742        document->setFocusedElement(0);
1743    else {
1744        Node* node = this->node();
1745        if (node && node->isElementNode()) {
1746            // If this node is already the currently focused node, then calling focus() won't do anything.
1747            // That is a problem when focus is removed from the webpage to chrome, and then returns.
1748            // In these cases, we need to do what keyboard and mouse focus do, which is reset focus first.
1749            if (document->focusedElement() == node)
1750                document->setFocusedElement(0);
1751
1752            toElement(node)->focus();
1753        } else {
1754            document->setFocusedElement(0);
1755        }
1756    }
1757}
1758
1759void AccessibilityRenderObject::setSelectedTextRange(const PlainTextRange& range)
1760{
1761    if (isNativeTextControl()) {
1762        HTMLTextFormControlElement* textControl = toRenderTextControl(m_renderer)->textFormControlElement();
1763        textControl->setSelectionRange(range.start, range.start + range.length);
1764        return;
1765    }
1766
1767    Document* document = m_renderer->document();
1768    if (!document)
1769        return;
1770    Frame* frame = document->frame();
1771    if (!frame)
1772        return;
1773    Node* node = m_renderer->node();
1774    frame->selection()->setSelection(VisibleSelection(Position(node, range.start, Position::PositionIsOffsetInAnchor),
1775        Position(node, range.start + range.length, Position::PositionIsOffsetInAnchor), DOWNSTREAM));
1776}
1777
1778void AccessibilityRenderObject::setValue(const String& string)
1779{
1780    if (!m_renderer || !m_renderer->node() || !m_renderer->node()->isElementNode())
1781        return;
1782    if (!m_renderer->isBoxModelObject())
1783        return;
1784    RenderBoxModelObject* renderer = toRenderBoxModelObject(m_renderer);
1785
1786    // FIXME: Do we want to do anything here for ARIA textboxes?
1787    if (renderer->isTextField()) {
1788        // FIXME: This is not safe!  Other elements could have a TextField renderer.
1789        toHTMLInputElement(m_renderer->node())->setValue(string);
1790    } else if (renderer->isTextArea()) {
1791        // FIXME: This is not safe!  Other elements could have a TextArea renderer.
1792        toHTMLTextAreaElement(m_renderer->node())->setValue(string);
1793    }
1794}
1795
1796void AccessibilityRenderObject::scrollTo(const IntPoint& point) const
1797{
1798    if (!m_renderer || !m_renderer->isBox())
1799        return;
1800
1801    RenderBox* box = toRenderBox(m_renderer);
1802    if (!box->canBeScrolledAndHasScrollableArea())
1803        return;
1804
1805    RenderLayer* layer = box->layer();
1806    layer->scrollToOffset(toIntSize(point), RenderLayer::ScrollOffsetClamped);
1807}
1808
1809//
1810// Notifications that this object may have changed.
1811//
1812
1813void AccessibilityRenderObject::handleActiveDescendantChanged()
1814{
1815    Element* element = toElement(renderer()->node());
1816    if (!element)
1817        return;
1818    Document* doc = renderer()->document();
1819    if (!doc->frame()->selection()->isFocusedAndActive() || doc->focusedElement() != element)
1820        return;
1821    AccessibilityRenderObject* activedescendant = static_cast<AccessibilityRenderObject*>(activeDescendant());
1822
1823    if (activedescendant && shouldNotifyActiveDescendant())
1824        doc->axObjectCache()->postNotification(m_renderer, AXObjectCache::AXActiveDescendantChanged, true);
1825}
1826
1827void AccessibilityRenderObject::handleAriaExpandedChanged()
1828{
1829    // Find if a parent of this object should handle aria-expanded changes.
1830    AccessibilityObject* containerParent = this->parentObject();
1831    while (containerParent) {
1832        bool foundParent = false;
1833
1834        switch (containerParent->roleValue()) {
1835        case TreeRole:
1836        case TreeGridRole:
1837        case GridRole:
1838        case TableRole:
1839        case BrowserRole:
1840            foundParent = true;
1841            break;
1842        default:
1843            break;
1844        }
1845
1846        if (foundParent)
1847            break;
1848
1849        containerParent = containerParent->parentObject();
1850    }
1851
1852    // Post that the row count changed.
1853    if (containerParent)
1854        axObjectCache()->postNotification(containerParent, document(), AXObjectCache::AXRowCountChanged, true);
1855
1856    // Post that the specific row either collapsed or expanded.
1857    if (roleValue() == RowRole || roleValue() == TreeItemRole)
1858        axObjectCache()->postNotification(this, document(), isExpanded() ? AXObjectCache::AXRowExpanded : AXObjectCache::AXRowCollapsed, true);
1859}
1860
1861//
1862// Text metrics. Most of these should be deprecated, needs major cleanup.
1863//
1864
1865// NOTE: Consider providing this utility method as AX API
1866int AccessibilityRenderObject::index(const VisiblePosition& position) const
1867{
1868    if (position.isNull() || !isTextControl())
1869        return -1;
1870
1871    if (renderObjectContainsPosition(m_renderer, position.deepEquivalent()))
1872        return indexForVisiblePosition(position);
1873
1874    return -1;
1875}
1876
1877VisiblePosition AccessibilityRenderObject::visiblePositionForIndex(int index) const
1878{
1879    if (!m_renderer)
1880        return VisiblePosition();
1881
1882    if (isNativeTextControl())
1883        return toRenderTextControl(m_renderer)->textFormControlElement()->visiblePositionForIndex(index);
1884
1885    if (!allowsTextRanges() && !m_renderer->isText())
1886        return VisiblePosition();
1887
1888    Node* node = m_renderer->node();
1889    if (!node)
1890        return VisiblePosition();
1891
1892    if (index <= 0)
1893        return VisiblePosition(firstPositionInOrBeforeNode(node), DOWNSTREAM);
1894
1895    RefPtr<Range> range = Range::create(m_renderer->document());
1896    range->selectNodeContents(node, IGNORE_EXCEPTION);
1897    CharacterIterator it(range.get());
1898    it.advance(index - 1);
1899    return VisiblePosition(Position(it.range()->endContainer(), it.range()->endOffset(), Position::PositionIsOffsetInAnch\
1900or), UPSTREAM);
1901}
1902
1903int AccessibilityRenderObject::indexForVisiblePosition(const VisiblePosition& pos) const
1904{
1905    if (isNativeTextControl()) {
1906        HTMLTextFormControlElement* textControl = toRenderTextControl(m_renderer)->textFormControlElement();
1907        return textControl->indexForVisiblePosition(pos);
1908    }
1909
1910    if (!isTextControl())
1911        return 0;
1912
1913    Node* node = m_renderer->node();
1914    if (!node)
1915        return 0;
1916
1917    Position indexPosition = pos.deepEquivalent();
1918    if (indexPosition.isNull() || highestEditableRoot(indexPosition, HasEditableAXRole) != node)
1919        return 0;
1920
1921    RefPtr<Range> range = Range::create(m_renderer->document());
1922    range->setStart(node, 0, IGNORE_EXCEPTION);
1923    range->setEnd(indexPosition, IGNORE_EXCEPTION);
1924
1925    return TextIterator::rangeLength(range.get());
1926}
1927
1928void AccessibilityRenderObject::lineBreaks(Vector<int>& lineBreaks) const
1929{
1930    if (!isTextControl())
1931        return;
1932
1933    VisiblePosition visiblePos = visiblePositionForIndex(0);
1934    VisiblePosition savedVisiblePos = visiblePos;
1935    visiblePos = nextLinePosition(visiblePos, 0);
1936    while (!visiblePos.isNull() && visiblePos != savedVisiblePos) {
1937        lineBreaks.append(indexForVisiblePosition(visiblePos));
1938        savedVisiblePos = visiblePos;
1939        visiblePos = nextLinePosition(visiblePos, 0);
1940    }
1941}
1942
1943// A substring of the text associated with this accessibility object that is
1944// specified by the given character range.
1945String AccessibilityRenderObject::stringForRange(const PlainTextRange& range) const
1946{
1947    if (!range.length)
1948        return String();
1949
1950    if (!isTextControl())
1951        return String();
1952
1953    String elementText = isPasswordField() ? String() : text();
1954    if (range.start + range.length > elementText.length())
1955        return String();
1956
1957    return elementText.substring(range.start, range.length);
1958}
1959
1960//
1961// Private.
1962//
1963
1964bool AccessibilityRenderObject::isAllowedChildOfTree() const
1965{
1966    // Determine if this is in a tree. If so, we apply special behavior to make it work like an AXOutline.
1967    AccessibilityObject* axObj = parentObject();
1968    bool isInTree = false;
1969    while (axObj) {
1970        if (axObj->isTree()) {
1971            isInTree = true;
1972            break;
1973        }
1974        axObj = axObj->parentObject();
1975    }
1976
1977    // If the object is in a tree, only tree items should be exposed (and the children of tree items).
1978    if (isInTree) {
1979        AccessibilityRole role = roleValue();
1980        if (role != TreeItemRole && role != StaticTextRole)
1981            return false;
1982    }
1983    return true;
1984}
1985
1986bool AccessibilityRenderObject::hasTextAlternative() const
1987{
1988    // ARIA: section 2A, bullet #3 says if aria-labeledby or aria-label appears, it should
1989    // override the "label" element association.
1990    if (!ariaLabeledByAttribute().isEmpty() || !getAttribute(aria_labelAttr).isEmpty())
1991        return true;
1992
1993    return false;
1994}
1995
1996void AccessibilityRenderObject::ariaListboxSelectedChildren(AccessibilityChildrenVector& result)
1997{
1998    bool isMulti = isMultiSelectable();
1999
2000    AccessibilityChildrenVector childObjects = children();
2001    unsigned childrenSize = childObjects.size();
2002    for (unsigned k = 0; k < childrenSize; ++k) {
2003        // Every child should have aria-role option, and if so, check for selected attribute/state.
2004        AccessibilityObject* child = childObjects[k].get();
2005        if (child->isSelected() && child->ariaRoleAttribute() == ListBoxOptionRole) {
2006            result.append(child);
2007            if (!isMulti)
2008                return;
2009        }
2010    }
2011}
2012
2013PlainTextRange AccessibilityRenderObject::ariaSelectedTextRange() const
2014{
2015    Node* node = m_renderer->node();
2016    if (!node)
2017        return PlainTextRange();
2018
2019    VisibleSelection visibleSelection = selection();
2020    RefPtr<Range> currentSelectionRange = visibleSelection.toNormalizedRange();
2021    if (!currentSelectionRange || !currentSelectionRange->intersectsNode(node, IGNORE_EXCEPTION))
2022        return PlainTextRange();
2023
2024    int start = indexForVisiblePosition(visibleSelection.start());
2025    int end = indexForVisiblePosition(visibleSelection.end());
2026
2027    return PlainTextRange(start, end - start);
2028}
2029
2030bool AccessibilityRenderObject::nodeIsTextControl(const Node* node) const
2031{
2032    if (!node)
2033        return false;
2034
2035    const AccessibilityObject* axObjectForNode = axObjectCache()->getOrCreate(const_cast<Node*>(node));
2036    if (!axObjectForNode)
2037        return false;
2038
2039    return axObjectForNode->isTextControl();
2040}
2041
2042bool AccessibilityRenderObject::isTabItemSelected() const
2043{
2044    if (!isTabItem() || !m_renderer)
2045        return false;
2046
2047    Node* node = m_renderer->node();
2048    if (!node || !node->isElementNode())
2049        return false;
2050
2051    // The ARIA spec says a tab item can also be selected if it is aria-labeled by a tabpanel
2052    // that has keyboard focus inside of it, or if a tabpanel in its aria-controls list has KB
2053    // focus inside of it.
2054    AccessibilityObject* focusedElement = focusedUIElement();
2055    if (!focusedElement)
2056        return false;
2057
2058    Vector<Element*> elements;
2059    elementsFromAttribute(elements, aria_controlsAttr);
2060
2061    unsigned count = elements.size();
2062    for (unsigned k = 0; k < count; ++k) {
2063        Element* element = elements[k];
2064        AccessibilityObject* tabPanel = axObjectCache()->getOrCreate(element);
2065
2066        // A tab item should only control tab panels.
2067        if (!tabPanel || tabPanel->roleValue() != TabPanelRole)
2068            continue;
2069
2070        AccessibilityObject* checkFocusElement = focusedElement;
2071        // Check if the focused element is a descendant of the element controlled by the tab item.
2072        while (checkFocusElement) {
2073            if (tabPanel == checkFocusElement)
2074                return true;
2075            checkFocusElement = checkFocusElement->parentObject();
2076        }
2077    }
2078
2079    return false;
2080}
2081
2082AccessibilityObject* AccessibilityRenderObject::internalLinkElement() const
2083{
2084    Element* element = anchorElement();
2085    if (!element)
2086        return 0;
2087
2088    // Right now, we do not support ARIA links as internal link elements
2089    if (!isHTMLAnchorElement(element))
2090        return 0;
2091    HTMLAnchorElement* anchor = toHTMLAnchorElement(element);
2092
2093    KURL linkURL = anchor->href();
2094    String fragmentIdentifier = linkURL.fragmentIdentifier();
2095    if (fragmentIdentifier.isEmpty())
2096        return 0;
2097
2098    // check if URL is the same as current URL
2099    KURL documentURL = m_renderer->document()->url();
2100    if (!equalIgnoringFragmentIdentifier(documentURL, linkURL))
2101        return 0;
2102
2103    Node* linkedNode = m_renderer->document()->findAnchor(fragmentIdentifier);
2104    if (!linkedNode)
2105        return 0;
2106
2107    // The element we find may not be accessible, so find the first accessible object.
2108    return firstAccessibleObjectFromNode(linkedNode);
2109}
2110
2111AccessibilityObject* AccessibilityRenderObject::accessibilityImageMapHitTest(HTMLAreaElement* area, const IntPoint& point) const
2112{
2113    if (!area)
2114        return 0;
2115
2116    AccessibilityObject* parent = axObjectCache()->getOrCreate(area->imageElement());
2117    if (!parent)
2118        return 0;
2119
2120    AccessibilityObject::AccessibilityChildrenVector children = parent->children();
2121    unsigned count = children.size();
2122    for (unsigned k = 0; k < count; ++k) {
2123        if (children[k]->elementRect().contains(point))
2124            return children[k].get();
2125    }
2126
2127    return 0;
2128}
2129
2130bool AccessibilityRenderObject::renderObjectIsObservable(RenderObject* renderer) const
2131{
2132    // AX clients will listen for AXValueChange on a text control.
2133    if (renderer->isTextControl())
2134        return true;
2135
2136    // AX clients will listen for AXSelectedChildrenChanged on listboxes.
2137    Node* node = renderer->node();
2138    if (nodeHasRole(node, "listbox") || (renderer->isBoxModelObject() && toRenderBoxModelObject(renderer)->isListBox()))
2139        return true;
2140
2141    // Textboxes should send out notifications.
2142    if (nodeHasRole(node, "textbox"))
2143        return true;
2144
2145    return false;
2146}
2147
2148RenderObject* AccessibilityRenderObject::renderParentObject() const
2149{
2150    if (!m_renderer)
2151        return 0;
2152
2153    RenderObject* parent = m_renderer->parent();
2154
2155    // Case 1: node is a block and is an inline's continuation. Parent
2156    // is the start of the continuation chain.
2157    RenderObject* startOfConts = 0;
2158    RenderObject* firstChild = 0;
2159    if (m_renderer->isRenderBlock() && (startOfConts = startOfContinuations(m_renderer)))
2160        parent = startOfConts;
2161
2162    // Case 2: node's parent is an inline which is some node's continuation; parent is
2163    // the earliest node in the continuation chain.
2164    else if (parent && parent->isRenderInline() && (startOfConts = startOfContinuations(parent)))
2165        parent = startOfConts;
2166
2167    // Case 3: The first sibling is the beginning of a continuation chain. Find the origin of that continuation.
2168    else if (parent && (firstChild = parent->firstChild()) && firstChild->node()) {
2169        // Get the node's renderer and follow that continuation chain until the first child is found
2170        RenderObject* nodeRenderFirstChild = firstChild->node()->renderer();
2171        while (nodeRenderFirstChild != firstChild) {
2172            for (RenderObject* contsTest = nodeRenderFirstChild; contsTest; contsTest = nextContinuation(contsTest)) {
2173                if (contsTest == firstChild) {
2174                    parent = nodeRenderFirstChild->parent();
2175                    break;
2176                }
2177            }
2178            if (firstChild == parent->firstChild())
2179                break;
2180            firstChild = parent->firstChild();
2181            if (!firstChild->node())
2182                break;
2183            nodeRenderFirstChild = firstChild->node()->renderer();
2184        }
2185    }
2186
2187    return parent;
2188}
2189
2190bool AccessibilityRenderObject::isDescendantOfElementType(const QualifiedName& tagName) const
2191{
2192    for (RenderObject* parent = m_renderer->parent(); parent; parent = parent->parent()) {
2193        if (parent->node() && parent->node()->hasTagName(tagName))
2194            return true;
2195    }
2196    return false;
2197}
2198
2199bool AccessibilityRenderObject::isSVGImage() const
2200{
2201    return remoteSVGRootElement();
2202}
2203
2204void AccessibilityRenderObject::detachRemoteSVGRoot()
2205{
2206    if (AccessibilitySVGRoot* root = remoteSVGRootElement())
2207        root->setParent(0);
2208}
2209
2210AccessibilitySVGRoot* AccessibilityRenderObject::remoteSVGRootElement() const
2211{
2212    if (!m_renderer || !m_renderer->isRenderImage())
2213        return 0;
2214
2215    ImageResource* cachedImage = toRenderImage(m_renderer)->cachedImage();
2216    if (!cachedImage)
2217        return 0;
2218
2219    Image* image = cachedImage->image();
2220    if (!image || !image->isSVGImage())
2221        return 0;
2222
2223    SVGImage* svgImage = static_cast<SVGImage*>(image);
2224    FrameView* frameView = svgImage->frameView();
2225    if (!frameView)
2226        return 0;
2227    Frame* frame = frameView->frame();
2228    if (!frame)
2229        return 0;
2230
2231    Document* doc = frame->document();
2232    if (!doc || !doc->isSVGDocument())
2233        return 0;
2234
2235    SVGSVGElement* rootElement = toSVGDocument(doc)->rootElement();
2236    if (!rootElement)
2237        return 0;
2238    RenderObject* rendererRoot = rootElement->renderer();
2239    if (!rendererRoot)
2240        return 0;
2241
2242    AccessibilityObject* rootSVGObject = frame->document()->axObjectCache()->getOrCreate(rendererRoot);
2243
2244    // In order to connect the AX hierarchy from the SVG root element from the loaded resource
2245    // the parent must be set, because there's no other way to get back to who created the image.
2246    ASSERT(rootSVGObject && rootSVGObject->isAccessibilitySVGRoot());
2247    if (!rootSVGObject->isAccessibilitySVGRoot())
2248        return 0;
2249
2250    return toAccessibilitySVGRoot(rootSVGObject);
2251}
2252
2253AccessibilityObject* AccessibilityRenderObject::remoteSVGElementHitTest(const IntPoint& point) const
2254{
2255    AccessibilityObject* remote = remoteSVGRootElement();
2256    if (!remote)
2257        return 0;
2258
2259    IntSize offset = point - roundedIntPoint(elementRect().location());
2260    return remote->accessibilityHitTest(IntPoint(offset));
2261}
2262
2263// The boundingBox for elements within the remote SVG element needs to be offset by its position
2264// within the parent page, otherwise they are in relative coordinates only.
2265void AccessibilityRenderObject::offsetBoundingBoxForRemoteSVGElement(LayoutRect& rect) const
2266{
2267    for (AccessibilityObject* parent = parentObject(); parent; parent = parent->parentObject()) {
2268        if (parent->isAccessibilitySVGRoot()) {
2269            rect.moveBy(parent->parentObject()->elementRect().location());
2270            break;
2271        }
2272    }
2273}
2274
2275// Hidden children are those that are not rendered or visible, but are specifically marked as aria-hidden=false,
2276// meaning that they should be exposed to the AX hierarchy.
2277void AccessibilityRenderObject::addHiddenChildren()
2278{
2279    Node* node = this->node();
2280    if (!node)
2281        return;
2282
2283    // First do a quick run through to determine if we have any hidden nodes (most often we will not).
2284    // If we do have hidden nodes, we need to determine where to insert them so they match DOM order as close as possible.
2285    bool shouldInsertHiddenNodes = false;
2286    for (Node* child = node->firstChild(); child; child = child->nextSibling()) {
2287        if (!child->renderer() && isNodeAriaVisible(child)) {
2288            shouldInsertHiddenNodes = true;
2289            break;
2290        }
2291    }
2292
2293    if (!shouldInsertHiddenNodes)
2294        return;
2295
2296    // Iterate through all of the children, including those that may have already been added, and
2297    // try to insert hidden nodes in the correct place in the DOM order.
2298    unsigned insertionIndex = 0;
2299    for (Node* child = node->firstChild(); child; child = child->nextSibling()) {
2300        if (child->renderer()) {
2301            // Find out where the last render sibling is located within m_children.
2302            AccessibilityObject* childObject = axObjectCache()->get(child->renderer());
2303            if (childObject && childObject->accessibilityIsIgnored()) {
2304                AccessibilityChildrenVector children = childObject->children();
2305                if (children.size())
2306                    childObject = children.last().get();
2307                else
2308                    childObject = 0;
2309            }
2310
2311            if (childObject)
2312                insertionIndex = m_children.find(childObject) + 1;
2313            continue;
2314        }
2315
2316        if (!isNodeAriaVisible(child))
2317            continue;
2318
2319        unsigned previousSize = m_children.size();
2320        if (insertionIndex > previousSize)
2321            insertionIndex = previousSize;
2322
2323        insertChild(axObjectCache()->getOrCreate(child), insertionIndex);
2324        insertionIndex += (m_children.size() - previousSize);
2325    }
2326}
2327
2328void AccessibilityRenderObject::addTextFieldChildren()
2329{
2330    Node* node = this->node();
2331    if (!node || !node->hasTagName(inputTag))
2332        return;
2333
2334    HTMLInputElement* input = toHTMLInputElement(node);
2335    HTMLElement* spinButtonElement = input->innerSpinButtonElement();
2336    if (!spinButtonElement || !spinButtonElement->isSpinButtonElement())
2337        return;
2338
2339    AccessibilitySpinButton* axSpinButton = static_cast<AccessibilitySpinButton*>(axObjectCache()->getOrCreate(SpinButtonRole));
2340    axSpinButton->setSpinButtonElement(static_cast<SpinButtonElement*>(spinButtonElement));
2341    axSpinButton->setParent(this);
2342    m_children.append(axSpinButton);
2343}
2344
2345void AccessibilityRenderObject::addImageMapChildren()
2346{
2347    RenderBoxModelObject* cssBox = renderBoxModelObject();
2348    if (!cssBox || !cssBox->isRenderImage())
2349        return;
2350
2351    HTMLMapElement* map = toRenderImage(cssBox)->imageMap();
2352    if (!map)
2353        return;
2354
2355    for (Element* current = ElementTraversal::firstWithin(map); current; current = ElementTraversal::next(current, map)) {
2356        // add an <area> element for this child if it has a link
2357        if (isHTMLAreaElement(current) && current->isLink()) {
2358            AccessibilityImageMapLink* areaObject = static_cast<AccessibilityImageMapLink*>(axObjectCache()->getOrCreate(ImageMapLinkRole));
2359            areaObject->setHTMLAreaElement(toHTMLAreaElement(current));
2360            areaObject->setHTMLMapElement(map);
2361            areaObject->setParent(this);
2362            if (!areaObject->accessibilityIsIgnored())
2363                m_children.append(areaObject);
2364            else
2365                axObjectCache()->remove(areaObject->axObjectID());
2366        }
2367    }
2368}
2369
2370void AccessibilityRenderObject::addCanvasChildren()
2371{
2372    if (!node() || !node()->hasTagName(canvasTag))
2373        return;
2374
2375    // If it's a canvas, it won't have rendered children, but it might have accessible fallback content.
2376    // Clear m_haveChildren because AccessibilityNodeObject::addChildren will expect it to be false.
2377    ASSERT(!m_children.size());
2378    m_haveChildren = false;
2379    AccessibilityNodeObject::addChildren();
2380}
2381
2382void AccessibilityRenderObject::addAttachmentChildren()
2383{
2384    if (!isAttachment())
2385        return;
2386
2387    // FrameView's need to be inserted into the AX hierarchy when encountered.
2388    Widget* widget = widgetForAttachmentView();
2389    if (!widget || !widget->isFrameView())
2390        return;
2391
2392    AccessibilityObject* axWidget = axObjectCache()->getOrCreate(widget);
2393    if (!axWidget->accessibilityIsIgnored())
2394        m_children.append(axWidget);
2395}
2396
2397void AccessibilityRenderObject::addRemoteSVGChildren()
2398{
2399    AccessibilitySVGRoot* root = remoteSVGRootElement();
2400    if (!root)
2401        return;
2402
2403    root->setParent(this);
2404
2405    if (root->accessibilityIsIgnored()) {
2406        AccessibilityChildrenVector children = root->children();
2407        unsigned length = children.size();
2408        for (unsigned i = 0; i < length; ++i)
2409            m_children.append(children[i]);
2410    } else
2411        m_children.append(root);
2412}
2413
2414void AccessibilityRenderObject::ariaSelectedRows(AccessibilityChildrenVector& result)
2415{
2416    // Get all the rows.
2417    AccessibilityChildrenVector allRows;
2418    if (isTree())
2419        ariaTreeRows(allRows);
2420    else if (isAccessibilityTable() && toAccessibilityTable(this)->supportsSelectedRows())
2421        allRows = toAccessibilityTable(this)->rows();
2422
2423    // Determine which rows are selected.
2424    bool isMulti = isMultiSelectable();
2425
2426    // Prefer active descendant over aria-selected.
2427    AccessibilityObject* activeDesc = activeDescendant();
2428    if (activeDesc && (activeDesc->isTreeItem() || activeDesc->isTableRow())) {
2429        result.append(activeDesc);
2430        if (!isMulti)
2431            return;
2432    }
2433
2434    unsigned count = allRows.size();
2435    for (unsigned k = 0; k < count; ++k) {
2436        if (allRows[k]->isSelected()) {
2437            result.append(allRows[k]);
2438            if (!isMulti)
2439                break;
2440        }
2441    }
2442}
2443
2444bool AccessibilityRenderObject::elementAttributeValue(const QualifiedName& attributeName) const
2445{
2446    if (!m_renderer)
2447        return false;
2448
2449    return equalIgnoringCase(getAttribute(attributeName), "true");
2450}
2451
2452bool AccessibilityRenderObject::inheritsPresentationalRole() const
2453{
2454    // ARIA states if an item can get focus, it should not be presentational.
2455    if (canSetFocusAttribute())
2456        return false;
2457
2458    // ARIA spec says that when a parent object is presentational, and it has required child elements,
2459    // those child elements are also presentational. For example, <li> becomes presentational from <ul>.
2460    // http://www.w3.org/WAI/PF/aria/complete#presentation
2461    if (roleValue() != ListItemRole && roleValue() != ListMarkerRole)
2462        return false;
2463
2464    AccessibilityObject* parent = parentObject();
2465    if (!parent->isAccessibilityRenderObject())
2466        return false;
2467
2468    Node* elementNode = static_cast<AccessibilityRenderObject*>(parent)->node();
2469    if (!elementNode || !elementNode->isElementNode())
2470        return false;
2471
2472    QualifiedName tagName = toElement(elementNode)->tagQName();
2473    if (tagName == ulTag || tagName == olTag || tagName == dlTag)
2474        return parent->roleValue() == PresentationalRole;
2475
2476    return false;
2477}
2478
2479LayoutRect AccessibilityRenderObject::computeElementRect() const
2480{
2481    RenderObject* obj = m_renderer;
2482
2483    if (!obj)
2484        return LayoutRect();
2485
2486    if (obj->node()) // If we are a continuation, we want to make sure to use the primary renderer.
2487        obj = obj->node()->renderer();
2488
2489    // absoluteFocusRingQuads will query the hierarchy below this element, which for large webpages can be very slow.
2490    // For a web area, which will have the most elements of any element, absoluteQuads should be used.
2491    // We should also use absoluteQuads for SVG elements, otherwise transforms won't be applied.
2492    Vector<FloatQuad> quads;
2493
2494    if (obj->isText())
2495        toRenderText(obj)->absoluteQuads(quads, 0, RenderText::ClipToEllipsis);
2496    else if (isWebArea() || isSeamlessWebArea() || obj->isSVGRoot())
2497        obj->absoluteQuads(quads);
2498    else
2499        obj->absoluteFocusRingQuads(quads);
2500
2501    LayoutRect result = boundingBoxForQuads(obj, quads);
2502
2503    Document* document = this->document();
2504    if (document && document->isSVGDocument())
2505        offsetBoundingBoxForRemoteSVGElement(result);
2506
2507    // The size of the web area should be the content size, not the clipped size.
2508    if ((isWebArea() || isSeamlessWebArea()) && obj->frame()->view())
2509        result.setSize(obj->frame()->view()->contentsSize());
2510
2511    // Checkboxes and radio buttons include their label as part of their rect.
2512    if (isCheckboxOrRadio()) {
2513        HTMLLabelElement* label = labelForElement(toElement(m_renderer->node()));
2514        if (label && label->renderer()) {
2515            LayoutRect labelRect = axObjectCache()->getOrCreate(label)->elementRect();
2516            result.unite(labelRect);
2517        }
2518    }
2519
2520    return result;
2521}
2522
2523} // namespace WebCore
2524