accessibilityrenderobject.cpp

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    if (isNativeTextControl())
        return toRenderTextControl(m_renderer)->visiblePositionForIndex(index);
    
    if (!isTextControl() && !m_renderer->isText())
        return VisiblePosition();
    
    Node* node = m_renderer->node();
    if (!node)
        return VisiblePosition();
    
    if (index <= 0)
        return VisiblePosition(node, 0, DOWNSTREAM);
    
    ExceptionCode ec = 0;
    RefPtr<Range> range = Range::create(m_renderer->document());
    range->selectNodeContents(node, ec);
    CharacterIterator it(range.get());
    it.advance(index - 1);
    return VisiblePosition(it.range()->endContainer(ec), it.range()->endOffset(ec), UPSTREAM);
}
    
int AccessibilityRenderObject::indexForVisiblePosition(const VisiblePosition& pos) const
{
    if (isNativeTextControl())
        return toRenderTextControl(m_renderer)->indexForVisiblePosition(pos);
    
    if (!isTextControl())
        return 0;
    
    Node* node = m_renderer->node();
    if (!node)
        return 0;
    
    Position indexPosition = pos.deepEquivalent();
    if (!indexPosition.node() || indexPosition.node()->rootEditableElement() != node)
        return 0;
    
    ExceptionCode ec = 0;
    RefPtr<Range> range = Range::create(m_renderer->document());
    range->setStart(node, 0, ec);
    range->setEnd(indexPosition.node(), indexPosition.offset(), ec);
    return TextIterator::rangeLength(range.get());
}

IntRect AccessibilityRenderObject::boundsForVisiblePositionRange(const VisiblePositionRange& visiblePositionRange) const
{
    if (visiblePositionRange.isNull())
        return IntRect();
    
    // Create a mutable VisiblePositionRange.
    VisiblePositionRange range(visiblePositionRange);
    IntRect rect1 = range.start.absoluteCaretBounds();
    IntRect rect2 = range.end.absoluteCaretBounds();
    
    // readjust for position at the edge of a line.  This is to exclude line rect that doesn't need to be accounted in the range bounds
    if (rect2.y() != rect1.y()) {
        VisiblePosition endOfFirstLine = endOfLine(range.start);
        if (range.start == endOfFirstLine) {
            range.start.setAffinity(DOWNSTREAM);
            rect1 = range.start.absoluteCaretBounds();
        }
        if (range.end == endOfFirstLine) {
            range.end.setAffinity(UPSTREAM);
            rect2 = range.end.absoluteCaretBounds();
        }
    }
    
    IntRect ourrect = rect1;
    ourrect.unite(rect2);
    
    // if the rectangle spans lines and contains multiple text chars, use the range's bounding box intead
    if (rect1.bottom() != rect2.bottom()) {
        RefPtr<Range> dataRange = makeRange(range.start, range.end);
        IntRect boundingBox = dataRange->boundingBox();
        String rangeString = plainText(dataRange.get());
        if (rangeString.length() > 1 && !boundingBox.isEmpty())
            ourrect = boundingBox;
    }
    
#if PLATFORM(MAC)
    return m_renderer->document()->view()->contentsToScreen(ourrect);
#else
    return ourrect;
#endif
}
    
void AccessibilityRenderObject::setSelectedVisiblePositionRange(const VisiblePositionRange& range) const
{
    if (range.start.isNull() || range.end.isNull())
        return;
    
    // make selection and tell the document to use it. if it's zero length, then move to that position
    if (range.start == range.end) {
        m_renderer->document()->frame()->selection()->moveTo(range.start, true);
    }
    else {
        VisibleSelection newSelection = VisibleSelection(range.start, range.end);
        m_renderer->document()->frame()->selection()->setSelection(newSelection);
    }    
}

VisiblePosition AccessibilityRenderObject::visiblePositionForPoint(const IntPoint& point) const
{
    // convert absolute point to view coordinates
    FrameView* frameView = m_renderer->document()->topDocument()->renderer()->view()->frameView();
    RenderView* renderView = topRenderer();
    Node* innerNode = 0;
    
    // locate the node containing the point
    IntPoint pointResult;
    while (1) {
        IntPoint ourpoint;
#if PLATFORM(MAC)
        ourpoint = frameView->screenToContents(point);
#else
        ourpoint = point;
#endif
        HitTestRequest request(HitTestRequest::ReadOnly |
                               HitTestRequest::Active);
        HitTestResult result(ourpoint);
        renderView->layer()->hitTest(request, result);
        innerNode = result.innerNode();
        if (!innerNode || !innerNode->renderer())
            return VisiblePosition();
        
        pointResult = result.localPoint();
        
        // done if hit something other than a widget
        RenderObject* renderer = innerNode->renderer();
        if (!renderer->isWidget())
            break;
        
        // descend into widget (FRAME, IFRAME, OBJECT...)
        Widget* widget = static_cast<RenderWidget*>(renderer)->widget();
        if (!widget || !widget->isFrameView())
            break;
        Frame* frame = static_cast<FrameView*>(widget)->frame();
        if (!frame)
            break;
        renderView = frame->document()->renderView();
        frameView = static_cast<FrameView*>(widget);
    }
    
    return innerNode->renderer()->positionForPoint(pointResult);
}

// NOTE: Consider providing this utility method as AX API
VisiblePosition AccessibilityRenderObject::visiblePositionForIndex(unsigned indexValue, bool lastIndexOK) const
{
    if (!isTextControl())
        return VisiblePosition();
    
    // lastIndexOK specifies whether the position after the last character is acceptable
    if (indexValue >= text().length()) {
        if (!lastIndexOK || indexValue > text().length())
            return VisiblePosition();
    }
    VisiblePosition position = visiblePositionForIndex(indexValue);
    position.setAffinity(DOWNSTREAM);
    return position;
}

// NOTE: Consider providing this utility method as AX API
int AccessibilityRenderObject::index(const VisiblePosition& position) const
{
    if (!isTextControl())
        return -1;
    
    Node* node = position.deepEquivalent().node();
    if (!node)
        return -1;
    
    for (RenderObject* renderer = node->renderer(); renderer && renderer->node(); renderer = renderer->parent()) {
        if (renderer == m_renderer)
            return indexForVisiblePosition(position);
    }
    
    return -1;
}

// Given a line number, the range of characters of the text associated with this accessibility
// object that contains the line number.
PlainTextRange AccessibilityRenderObject::doAXRangeForLine(unsigned lineNumber) const
{
    if (!isTextControl())
        return PlainTextRange();
    
    // iterate to the specified line
    VisiblePosition visiblePos = visiblePositionForIndex(0);
    VisiblePosition savedVisiblePos;
    for (unsigned lineCount = lineNumber; lineCount != 0; lineCount -= 1) {
        savedVisiblePos = visiblePos;
        visiblePos = nextLinePosition(visiblePos, 0);
        if (visiblePos.isNull() || visiblePos == savedVisiblePos)
            return PlainTextRange();
    }
    
    // make a caret selection for the marker position, then extend it to the line
    // NOTE: ignores results of selection.modify because it returns false when
    // starting at an empty line.  The resulting selection in that case
    // will be a caret at visiblePos.
    SelectionController selection;
    selection.setSelection(VisibleSelection(visiblePos));
    selection.modify(SelectionController::EXTEND, SelectionController::LEFT, LineBoundary);
    selection.modify(SelectionController::EXTEND, SelectionController::RIGHT, LineBoundary);
    
    // calculate the indices for the selection start and end
    VisiblePosition startPosition = selection.selection().visibleStart();
    VisiblePosition endPosition = selection.selection().visibleEnd();
    int index1 = indexForVisiblePosition(startPosition);
    int index2 = indexForVisiblePosition(endPosition);
    
    // add one to the end index for a line break not caused by soft line wrap (to match AppKit)
    if (endPosition.affinity() == DOWNSTREAM && endPosition.next().isNotNull())
        index2 += 1;
    
    // return nil rather than an zero-length range (to match AppKit)
    if (index1 == index2)
        return PlainTextRange();
    
    return PlainTextRange(index1, index2 - index1);
}

// The composed character range in the text associated with this accessibility object that
// is specified by the given index value. This parameterized attribute returns the complete
// range of characters (including surrogate pairs of multi-byte glyphs) at the given index.
PlainTextRange AccessibilityRenderObject::doAXRangeForIndex(unsigned index) const
{
    if (!isTextControl())
        return PlainTextRange();
    
    String elementText = text();
    if (!elementText.length() || index > elementText.length() - 1)
        return PlainTextRange();
    
    return PlainTextRange(index, 1);
}

// A substring of the text associated with this accessibility object that is
// specified by the given character range.
String AccessibilityRenderObject::doAXStringForRange(const PlainTextRange& range) const
{
    if (isPasswordField())
        return String();
    
    if (range.length == 0)
        return "";
    
    if (!isTextControl())
        return String();
    
    String elementText = text();
    if (range.start + range.length > elementText.length())
        return String();
    
    return elementText.substring(range.start, range.length);
}

// The bounding rectangle of the text associated with this accessibility object that is
// specified by the given range. This is the bounding rectangle a sighted user would see
// on the display screen, in pixels.
IntRect AccessibilityRenderObject::doAXBoundsForRange(const PlainTextRange& range) const
{
    if (isTextControl())
        return boundsForVisiblePositionRange(visiblePositionRangeForRange(range));
    return IntRect();
}

AccessibilityObject* AccessibilityRenderObject::doAccessibilityHitTest(const IntPoint& point) const
{
    if (!m_renderer || !m_renderer->hasLayer())
        return 0;
    
    RenderLayer* layer = toRenderBox(m_renderer)->layer();
     
    HitTestRequest request(HitTestRequest::ReadOnly |
                           HitTestRequest::Active);
    HitTestResult hitTestResult = HitTestResult(point);
    layer->hitTest(request, hitTestResult);
    if (!hitTestResult.innerNode())
        return 0;
    Node* node = hitTestResult.innerNode()->shadowAncestorNode();
    RenderObject* obj = node->renderer();
    if (!obj)
        return 0;
    
    AccessibilityObject *result = obj->document()->axObjectCache()->getOrCreate(obj);

    if (obj->isListBox())
        return static_cast<AccessibilityListBox*>(result)->doAccessibilityHitTest(point);
        
    if (result->accessibilityIsIgnored())
        result = result->parentObjectUnignored();

    return result;
}

AccessibilityObject* AccessibilityRenderObject::focusedUIElement() const
{
    // get the focused node in the page
    Page* page = m_renderer->document()->page();
    if (!page)
        return 0;
    
    Document* focusedDocument = page->focusController()->focusedOrMainFrame()->document();
    Node* focusedNode = focusedDocument->focusedNode();
    if (!focusedNode)
        focusedNode = focusedDocument;
    
    RenderObject* focusedNodeRenderer = focusedNode->renderer();
    if (!focusedNodeRenderer)
        return 0;
    
    AccessibilityObject* obj = focusedNodeRenderer->document()->axObjectCache()->getOrCreate(focusedNodeRenderer);
    
    if (obj->shouldFocusActiveDescendant()) {
        if (AccessibilityObject* descendant = obj->activeDescendant())
            obj = descendant;
    }
    
    // the HTML element, for example, is focusable but has an AX object that is ignored
    if (obj->accessibilityIsIgnored())
        obj = obj->parentObjectUnignored();
    
    return obj;
}

bool AccessibilityRenderObject::shouldFocusActiveDescendant() const
{
    switch (ariaRoleAttribute()) {
    case GroupRole:
    case ComboBoxRole:
    case ListBoxRole:
    case MenuRole:
    case MenuBarRole:
    case RadioGroupRole:
    case RowRole:
    case PopUpButtonRole:
    case ProgressIndicatorRole:
    case ToolbarRole:
    case OutlineRole:
    /* FIXME: replace these with actual roles when they are added to AccessibilityRole
    composite
    alert
    alertdialog
    grid
    status
    timer
    tree
    */
        return true;
    default:
        return false;
    }
}

AccessibilityObject* AccessibilityRenderObject::activeDescendant() const
{
    if (renderer()->node() && !renderer()->node()->isElementNode())
        return 0;
    Element* element = static_cast<Element*>(renderer()->node());
        
    String activeDescendantAttrStr = element->getAttribute(aria_activedescendantAttr).string();
    if (activeDescendantAttrStr.isNull() || activeDescendantAttrStr.isEmpty())
        return 0;
    
    Element* target = renderer()->document()->getElementById(activeDescendantAttrStr);
    if (!target)
        return 0;
    
    AccessibilityObject* obj = renderer()->document()->axObjectCache()->getOrCreate(target->renderer());
    if (obj->isAccessibilityRenderObject())
    // an activedescendant is only useful if it has a renderer, because that's what's needed to post the notification
        return obj;
    return 0;
}


void AccessibilityRenderObject::handleActiveDescendantChanged()
{
    Element* element = static_cast<Element*>(renderer()->node());
    if (!element)
        return;
    Document* doc = renderer()->document();
    if (!doc->frame()->selection()->isFocusedAndActive() || doc->focusedNode() != element)
        return; 
    AccessibilityRenderObject* activedescendant = static_cast<AccessibilityRenderObject*>(activeDescendant());
    
    if (activedescendant && shouldFocusActiveDescendant())
        doc->axObjectCache()->postNotificationToElement(activedescendant->renderer(), "AXFocusedUIElementChanged");
}


AccessibilityObject* AccessibilityRenderObject::observableObject() const
{
    for (RenderObject* renderer = m_renderer; renderer && renderer->node(); renderer = renderer->parent()) {
        if (renderer->isTextControl())
            return renderer->document()->axObjectCache()->getOrCreate(renderer);
    }
    
    return 0;
}
    
typedef HashMap<String, AccessibilityRole, CaseFoldingHash> ARIARoleMap;

static const ARIARoleMap& createARIARoleMap()
{
    struct RoleEntry {
        String