accessibilityobject.cpp

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VisiblePositionRange AccessibilityObject::visiblePositionRangeForUnorderedPositions(const VisiblePosition& visiblePos1, const VisiblePosition& visiblePos2) const
{
    if (visiblePos1.isNull() || visiblePos2.isNull())
        return VisiblePositionRange();

    VisiblePosition startPos;
    VisiblePosition endPos;
    bool alreadyInOrder;

    // upstream is ordered before downstream for the same position
    if (visiblePos1 == visiblePos2 && visiblePos2.affinity() == UPSTREAM)
        alreadyInOrder = false;

    // use selection order to see if the positions are in order
    else
        alreadyInOrder = VisibleSelection(visiblePos1, visiblePos2).isBaseFirst();

    if (alreadyInOrder) {
        startPos = visiblePos1;
        endPos = visiblePos2;
    } else {
        startPos = visiblePos2;
        endPos = visiblePos1;
    }

    return VisiblePositionRange(startPos, endPos);
}

VisiblePositionRange AccessibilityObject::positionOfLeftWord(const VisiblePosition& visiblePos) const
{
    VisiblePosition startPosition = startOfWord(visiblePos, LeftWordIfOnBoundary);
    VisiblePosition endPosition = endOfWord(startPosition);
    return VisiblePositionRange(startPosition, endPosition);
}

VisiblePositionRange AccessibilityObject::positionOfRightWord(const VisiblePosition& visiblePos) const
{
    VisiblePosition startPosition = startOfWord(visiblePos, RightWordIfOnBoundary);
    VisiblePosition endPosition = endOfWord(startPosition);
    return VisiblePositionRange(startPosition, endPosition);
}

static VisiblePosition updateAXLineStartForVisiblePosition(const VisiblePosition& visiblePosition)
{
    // A line in the accessibility sense should include floating objects, such as aligned image, as part of a line.
    // So let's update the position to include that.
    VisiblePosition tempPosition;
    VisiblePosition startPosition = visiblePosition;
    Position p;
    RenderObject* renderer;
    while (true) {
        tempPosition = startPosition.previous();
        if (tempPosition.isNull())
            break;
        p = tempPosition.deepEquivalent();
        if (!p.node())
            break;
        renderer = p.node()->renderer();
        if (!renderer || renderer->isRenderBlock() && !p.offset())
            break;
        InlineBox* box;
        int ignoredCaretOffset;
        p.getInlineBoxAndOffset(tempPosition.affinity(), box, ignoredCaretOffset);
        if (box)
            break;
        startPosition = tempPosition;
    }

    return startPosition;
}

VisiblePositionRange AccessibilityObject::leftLineVisiblePositionRange(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePositionRange();

    // make a caret selection for the position before marker position (to make sure
    // we move off of a line start)
    VisiblePosition prevVisiblePos = visiblePos.previous();
    if (prevVisiblePos.isNull())
        return VisiblePositionRange();

    VisiblePosition startPosition = startOfLine(prevVisiblePos);

    // keep searching for a valid line start position.  Unless the VisiblePosition is at the very beginning, there should
    // always be a valid line range.  However, startOfLine will return null for position next to a floating object,
    // since floating object doesn't really belong to any line.
    // This check will reposition the marker before the floating object, to ensure we get a line start.
    if (startPosition.isNull()) {
        while (startPosition.isNull() && prevVisiblePos.isNotNull()) {
            prevVisiblePos = prevVisiblePos.previous();
            startPosition = startOfLine(prevVisiblePos);
        }
    } else
        startPosition = updateAXLineStartForVisiblePosition(startPosition);

    VisiblePosition endPosition = endOfLine(prevVisiblePos);
    return VisiblePositionRange(startPosition, endPosition);
}

VisiblePositionRange AccessibilityObject::rightLineVisiblePositionRange(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePositionRange();

    // make sure we move off of a line end
    VisiblePosition nextVisiblePos = visiblePos.next();
    if (nextVisiblePos.isNull())
        return VisiblePositionRange();

    VisiblePosition startPosition = startOfLine(nextVisiblePos);

    // fetch for a valid line start position
    if (startPosition.isNull() ) {
        startPosition = visiblePos;
        nextVisiblePos = nextVisiblePos.next();
    } else
        startPosition = updateAXLineStartForVisiblePosition(startPosition);

    VisiblePosition endPosition = endOfLine(nextVisiblePos);

    // as long as the position hasn't reached the end of the doc,  keep searching for a valid line end position
    // Unless the VisiblePosition is at the very end, there should always be a valid line range.  However, endOfLine will
    // return null for position by a floating object, since floating object doesn't really belong to any line.
    // This check will reposition the marker after the floating object, to ensure we get a line end.
    while (endPosition.isNull() && nextVisiblePos.isNotNull()) {
        nextVisiblePos = nextVisiblePos.next();
        endPosition = endOfLine(nextVisiblePos);
    }

    return VisiblePositionRange(startPosition, endPosition);
}

VisiblePositionRange AccessibilityObject::sentenceForPosition(const VisiblePosition& visiblePos) const
{
    // FIXME: FO 2 IMPLEMENT (currently returns incorrect answer)
    // Related? <rdar://problem/3927736> Text selection broken in 8A336
    VisiblePosition startPosition = startOfSentence(visiblePos);
    VisiblePosition endPosition = endOfSentence(startPosition);
    return VisiblePositionRange(startPosition, endPosition);
}

VisiblePositionRange AccessibilityObject::paragraphForPosition(const VisiblePosition& visiblePos) const
{
    VisiblePosition startPosition = startOfParagraph(visiblePos);
    VisiblePosition endPosition = endOfParagraph(startPosition);
    return VisiblePositionRange(startPosition, endPosition);
}

static VisiblePosition startOfStyleRange(const VisiblePosition visiblePos)
{
    RenderObject* renderer = visiblePos.deepEquivalent().node()->renderer();
    RenderObject* startRenderer = renderer;
    RenderStyle* style = renderer->style();

    // traverse backward by renderer to look for style change
    for (RenderObject* r = renderer->previousInPreOrder(); r; r = r->previousInPreOrder()) {
        // skip non-leaf nodes
        if (r->firstChild())
            continue;

        // stop at style change
        if (r->style() != style)
            break;

        // remember match
        startRenderer = r;
    }

    return VisiblePosition(startRenderer->node(), 0, VP_DEFAULT_AFFINITY);
}

static VisiblePosition endOfStyleRange(const VisiblePosition visiblePos)
{
    RenderObject* renderer = visiblePos.deepEquivalent().node()->renderer();
    RenderObject* endRenderer = renderer;
    RenderStyle* style = renderer->style();

    // traverse forward by renderer to look for style change
    for (RenderObject* r = renderer->nextInPreOrder(); r; r = r->nextInPreOrder()) {
        // skip non-leaf nodes
        if (r->firstChild())
            continue;

        // stop at style change
        if (r->style() != style)
            break;

        // remember match
        endRenderer = r;
    }

    return VisiblePosition(endRenderer->node(), maxDeepOffset(endRenderer->node()), VP_DEFAULT_AFFINITY);
}

VisiblePositionRange AccessibilityObject::styleRangeForPosition(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePositionRange();

    return VisiblePositionRange(startOfStyleRange(visiblePos), endOfStyleRange(visiblePos));
}

// NOTE: Consider providing this utility method as AX API
VisiblePositionRange AccessibilityObject::visiblePositionRangeForRange(const PlainTextRange& range) const
{
    if (range.start + range.length > text().length())
        return VisiblePositionRange();

    VisiblePosition startPosition = visiblePositionForIndex(range.start);
    startPosition.setAffinity(DOWNSTREAM);
    VisiblePosition endPosition = visiblePositionForIndex(range.start + range.length);
    return VisiblePositionRange(startPosition, endPosition);
}

static bool replacedNodeNeedsCharacter(Node* replacedNode)
{
    // we should always be given a rendered node and a replaced node, but be safe
    // replaced nodes are either attachments (widgets) or images
    if (!replacedNode || !replacedNode->renderer() || !replacedNode->renderer()->isReplaced() || replacedNode->isTextNode()) {
        return false;
    }

    // create an AX object, but skip it if it is not supposed to be seen
    AccessibilityObject* object = replacedNode->renderer()->document()->axObjectCache()->getOrCreate(replacedNode->renderer());
    if (object->accessibilityIsIgnored())
        return false;

    return true;
}

String AccessibilityObject::stringForVisiblePositionRange(const VisiblePositionRange& visiblePositionRange) const
{
    if (visiblePositionRange.isNull())
        return String();

    Vector<UChar> resultVector;
    RefPtr<Range> range = makeRange(visiblePositionRange.start, visiblePositionRange.end);
    for (TextIterator it(range.get()); !it.atEnd(); it.advance()) {
        // non-zero length means textual node, zero length means replaced node (AKA "attachments" in AX)
        if (it.length() != 0) {
            resultVector.append(it.characters(), it.length());
        } else {
            // locate the node and starting offset for this replaced range
            int exception = 0;
            Node* node = it.range()->startContainer(exception);
            ASSERT(node == it.range()->endContainer(exception));
            int offset = it.range()->startOffset(exception);

            if (replacedNodeNeedsCharacter(node->childNode(offset))) {
                resultVector.append(objectReplacementCharacter);
            }
        }
    }

    return String::adopt(resultVector);
}

IntRect AccessibilityObject::boundsForVisiblePositionRange(const VisiblePositionRange&) const
{
    return IntRect();
}

int AccessibilityObject::lengthForVisiblePositionRange(const VisiblePositionRange& visiblePositionRange) const
{
    // FIXME: Multi-byte support
    if (visiblePositionRange.isNull())
        return -1;
    
    int length = 0;
    RefPtr<Range> range = makeRange(visiblePositionRange.start, visiblePositionRange.end);
    for (TextIterator it(range.get()); !it.atEnd(); it.advance()) {
        // non-zero length means textual node, zero length means replaced node (AKA "attachments" in AX)
        if (it.length() != 0) {
            length += it.length();
        } else {
            // locate the node and starting offset for this replaced range
            int exception = 0;
            Node* node = it.range()->startContainer(exception);
            ASSERT(node == it.range()->endContainer(exception));
            int offset = it.range()->startOffset(exception);

            if (replacedNodeNeedsCharacter(node->childNode(offset)))
                length++;
        }
    }
    
    return length;
}

void AccessibilityObject::setSelectedVisiblePositionRange(const VisiblePositionRange&) const
{
}

VisiblePosition AccessibilityObject::visiblePositionForPoint(const IntPoint&) const
{
    return VisiblePosition();
}

VisiblePosition AccessibilityObject::nextVisiblePosition(const VisiblePosition& visiblePos) const
{
    return visiblePos.next();
}

VisiblePosition AccessibilityObject::previousVisiblePosition(const VisiblePosition& visiblePos) const
{
    return visiblePos.previous();
}

VisiblePosition AccessibilityObject::nextWordEnd(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePosition();

    // make sure we move off of a word end
    VisiblePosition nextVisiblePos = visiblePos.next();
    if (nextVisiblePos.isNull())
        return VisiblePosition();

    return endOfWord(nextVisiblePos, LeftWordIfOnBoundary);
}

VisiblePosition AccessibilityObject::previousWordStart(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePosition();

    // make sure we move off of a word start
    VisiblePosition prevVisiblePos = visiblePos.previous();
    if (prevVisiblePos.isNull())
        return VisiblePosition();

    return startOfWord(prevVisiblePos, RightWordIfOnBoundary);
}

VisiblePosition AccessibilityObject::nextLineEndPosition(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePosition();

    // to make sure we move off of a line end
    VisiblePosition nextVisiblePos = visiblePos.next();
    if (nextVisiblePos.isNull())
        return VisiblePosition();