Implements the ability to get and set the caret position and the current selection from anywhere in…

Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 1816 matching lines @@
 }
 
 Widget* AXLayoutObject::widgetForAttachmentView() const
 {
     if (!isAttachment())
         return 0;
     return toLayoutPart(m_layoutObject)->widget();
 }
 
 //
-// Selected text.
+// Get the current selection.
 //
 
-AXObject::PlainTextRange AXLayoutObject::selectedTextRange() const
+AXObject::AXRange AXLayoutObject::selection() const
 {
-    if (!isTextControl())
-        return PlainTextRange();
+    AXRange textSelection = textControlSelection();
+    if (!textSelection.isNull())
+        return textSelection;
 
-    if (m_layoutObject->isTextControl()) {
-        HTMLTextFormControlElement* textControl = toLayoutTextControl(m_layoutObject)->textFormControlElement();
-        return PlainTextRange(textControl->selectionStart(), textControl->selectionEnd() - textControl->selectionStart());
+    // Find the closest parent that has a node.

[dmazzoni, 2015/06/22 17:13:35]

I don't think you need to find a parent with a node here. If layoutObject() is
null, exit early - and otherwise just get visibleSelection().

+    const AXObject* axObject = this;
+    while (axObject
+        && (!axObject->isAXLayoutObject() || !axObject->node()
+        || axObject->accessibilityIsIgnored()))
+        axObject = axObject->parentObject();
+    if (!axObject)
+        return AXRange();
+
+    VisibleSelection selection = axObject->visibleSelection();
+    RefPtrWillBeRawPtr<Range> selectionRange = selection.firstRange();
+    if (!selectionRange)
+        return AXRange();
+
+    Node* anchorNode = selectionRange->startContainer();
+    ASSERT(anchorNode);
+    RefPtrWillBeRawPtr<AXObject> anchorObject = axObjectCache()->get(anchorNode);
+    Node* focusNode = selectionRange->endContainer();
+    ASSERT(focusNode);
+    RefPtrWillBeRawPtr<AXObject> focusObject = axObjectCache()->get(focusNode);
+
+    if (!anchorObject || !focusObject)

[dmazzoni, 2015/06/22 17:13:35]

Here's where you need to walk up the tree. anchorNode and focusNode might both
be reasonable but might not have AX objects for some reason. Walk up until you
find one that does.

+        return AXRange();
+
+    int anchorOffset = selectionRange->startOffset();
+    ASSERT(anchorOffset >= 0);
+    int focusOffset = selectionRange->endOffset();
+    ASSERT(focusOffset >= 0);
+
+    return AXRange(
+        anchorObject, anchorOffset,
+        focusObject, focusOffset);
+}
+
+// Gets only the start and end offsets of the selection computed using the
+// current object as the starting point. Returns a null selection if there is
+// no selection in the subtree rooted at this object.
+AXObject::AXRange AXLayoutObject::selectionUnderObject() const
+{
+    AXRange textSelection = textControlSelection();
+    if (!textSelection.isNull())
+        return textSelection;
+
+    if (!node())
+        return AXRange();
+
+    VisibleSelection selection = visibleSelection();
+    RefPtrWillBeRawPtr<Range> selectionRange = selection.firstRange();
+    if (!selectionRange
+        || !selectionRange->intersectsNode(node(), IGNORE_EXCEPTION))

[dmazzoni, 2015/06/22 17:13:35]

It looks like selectionUnderObject returns a selection that intersects this node
- but that might be one that starts before this node and ends after this node.
Is that what you want?

+        return AXRange();
+
+    int start = indexForVisiblePosition(selection.visibleStart());
+    int end = indexForVisiblePosition(selection.visibleEnd());
+
+    return AXRange(start, end);
+}
+
+AXObject::AXRange AXLayoutObject::textControlSelection() const
+{
+    if (!layoutObject())
+        return AXRange();
+
+    Node* node = isHTMLTextFormControlElement(node()) ? node() :
+        document()->focusedElement();
+
+    if (!node)
+        return AXRange();
+
+    AXObject axObject = axObjectCache()->get(node);
+    if (!axObject)
+        return AXRange();
+
+    HTMLTextFormControlElement* textControl = toHTMLTextFormControlElement(node);
+    int start = textControl->selectionStart();
+    int end = textControl->selectionEnd();
+    return AXRange(axObject, start, axObject, end);
+}
+
+VisibleSelection AXLayoutObject::visibleSelection() const

[dmazzoni, 2015/06/22 17:13:35]

I'd just delete this helper, because any function that calls it should already
early-out if layoutObject() is null, and it doesn't do anything other than
return layoutObject()->frame()->selection().selection().

+{
+    return layoutObject() ?
+        layoutObject()->frame()->selection().selection() : VisibleSelection();
+}
+
+int AXLayoutObject::indexForVisiblePosition(const VisiblePosition& position) const
+{
+    if (layoutObject() && layoutObject()->isTextControl()) {
+        HTMLTextFormControlElement* textControl = toLayoutTextControl(
+            layoutObject())->textFormControlElement();
+        return textControl->indexForVisiblePosition(position);
     }
 
-    return visibleSelectionUnderObject();
-}
+    if (!node())
+        return 0;
 
-VisibleSelection AXLayoutObject::selection() const
-{
-    return m_layoutObject->frame()->selection().selection();
+    Position indexPosition = position.deepEquivalent();
+    if (indexPosition.isNull())
+        return 0;
+
+    RefPtrWillBeRawPtr<Range> range = Range::create(*document());
+    range->setStart(node(), 0, IGNORE_EXCEPTION);
+    range->setEnd(indexPosition, IGNORE_EXCEPTION);
+
+    return TextIterator::rangeLength(range->startPosition(), range->endPosition());
 }
 
 //
 // Modify or take an action on an object.
 //
 
-void AXLayoutObject::setSelectedTextRange(const PlainTextRange& range)
+void AXLayoutObject::setSelection(const AXRange& selection)
 {
-    if (m_layoutObject->isTextControl()) {
-        HTMLTextFormControlElement* textControl = toLayoutTextControl(m_layoutObject)->textFormControlElement();
-        textControl->setSelectionRange(range.start, range.start + range.length, SelectionHasNoDirection, NotDispatchSelectEvent);
+    if (selection.isNull())
+        return;
+
+    AXObject* anchorObject = this;
+    if (selection.anchorObject
+        && axObjectCache()->isIDinUse(selection.anchorObject->axObjectID()))

[dmazzoni, 2015/06/22 17:13:35]

Rather than isIDinUse, just check selection.anchorObject->isDetached to see if
it's valid.

Maybe also check that selection.anchorObject->axObjectCache() ==
axObjectCache(), and same for focusObject.

Checking isIDinUse could be subtly wrong if you're passed an AXObject from a
totally different cache that has its own ID mapping!

+        anchorObject = selection.anchorObject.get();
+
+    AXObject* focusObject = this;
+    if (selection.focusObject
+        && axObjectCache()->isIDinUse(selection.focusObject->axObjectID()))
+        focusObject = selection.focusObject.get();
+
+    if (anchorObject == this && anchorObject == focusObject
+        && layoutObject() && layoutObject()->isTextControl()) {
+        HTMLTextFormControlElement* textControl = toLayoutTextControl(
+            layoutObject())->textFormControlElement();
+        textControl->setSelectionRange(selection.anchorOffset, selection.focusOffset,
+            SelectionHasNoDirection, NotDispatchSelectEvent);
         return;
     }
 
-    Document& document = m_layoutObject->document();
-    LocalFrame* frame = document.frame();
+    Node* anchorNode = anchorObject->node();

[dmazzoni, 2015/06/22 17:13:35]

Need to walk up the tree here - someone might want to select a range where the
start or end of the range is a valid object in the tree that doesn't have a
node.

+    Node* focusNode = focusObject->node();
+    if (!anchorNode || !focusNode)
+        return;
+
+    Document* objectDocument = document();
+    ASSERT(objectDocument);
+    LocalFrame* frame = objectDocument->frame();
     if (!frame)
         return;
-    Node* node = m_layoutObject->node();
-    frame->selection().setSelection(VisibleSelection(Position(node, range.start, Position::PositionIsOffsetInAnchor),
-        Position(node, range.start + range.length, Position::PositionIsOffsetInAnchor), DOWNSTREAM));
+
+    frame->selection().setSelection(VisibleSelection(Position(anchorNode,
+        selection.anchorOffset, Position::PositionIsOffsetInAnchor),
+        Position(focusNode, selection.focusOffset,
+        Position::PositionIsOffsetInAnchor), DOWNSTREAM));
 }
 
 void AXLayoutObject::setValue(const String& string)
 {
     if (!node() || !node()->isElementNode())
         return;
     if (!m_layoutObject || !m_layoutObject->isBoxModelObject())
         return;
 
     LayoutBoxModelObject* layoutObject = toLayoutBoxModelObject(m_layoutObject);
@@ skipping 114 matching lines @@
     Position start, end;
     bool selected = Range::selectNodeContents(node, start, end);
     if (!selected)
         return VisiblePosition();
 
     CharacterIterator it(start, end);
     it.advance(index - 1);
     return VisiblePosition(Position(it.currentContainer(), it.endOffset(), Position::PositionIsOffsetInAnchor), UPSTREAM);
 }
 
-int AXLayoutObject::indexForVisiblePosition(const VisiblePosition& pos) const
-{
-    if (m_layoutObject->isTextControl()) {
-        HTMLTextFormControlElement* textControl = toLayoutTextControl(m_layoutObject)->textFormControlElement();
-        return textControl->indexForVisiblePosition(pos);
-    }
-
-    if (!isTextControl())
-        return 0;
-
-    Node* node = m_layoutObject->node();
-    if (!node)
-        return 0;
-
-    Position indexPosition = pos.deepEquivalent();
-    if (indexPosition.isNull()
-        || (highestEditableRoot(indexPosition) != node
-        && highestEditableRoot(indexPosition, HasEditableAXRole) != node))
-        return 0;
-
-    RefPtrWillBeRawPtr<Range> range = Range::create(m_layoutObject->document());
-    range->setStart(node, 0, IGNORE_EXCEPTION);
-    range->setEnd(indexPosition, IGNORE_EXCEPTION);
-
-    return TextIterator::rangeLength(range->startPosition(), range->endPosition());
-}
-
 void AXLayoutObject::addInlineTextBoxChildren(bool force)
 {
     Settings* settings = document()->settings();
     if (!force && (!settings || !settings->inlineTextBoxAccessibilityEnabled()))
         return;
 
     if (!layoutObject() || !layoutObject()->isText())
         return;
 
     if (layoutObject()->needsLayout()) {
@@ skipping 61 matching lines @@
     for (const auto& child : children()) {
         // Every child should have aria-role option, and if so, check for selected attribute/state.
         if (child->isSelected() && child->ariaRoleAttribute() == ListBoxOptionRole) {
             result.append(child);
             if (!isMulti)
                 return;
         }
     }
 }
 
-AXObject::PlainTextRange AXLayoutObject::visibleSelectionUnderObject() const
-{
-    Node* node = m_layoutObject->node();
-    if (!node)
-        return PlainTextRange();
-
-    VisibleSelection visibleSelection = selection();
-    RefPtrWillBeRawPtr<Range> currentSelectionRange = visibleSelection.toNormalizedRange();
-    if (!currentSelectionRange || !currentSelectionRange->intersectsNode(node, IGNORE_EXCEPTION))
-        return PlainTextRange();
-
-    int start = indexForVisiblePosition(visibleSelection.visibleStart());
-    int end = indexForVisiblePosition(visibleSelection.visibleEnd());
-
-    return PlainTextRange(start, end - start);
-}
-
 bool AXLayoutObject::nodeIsTextControl(const Node* node) const
 {
     if (!node)
         return false;
 
     const AXObject* axObjectForNode = axObjectCache()->getOrCreate(const_cast<Node*>(node));
     if (!axObjectForNode)
         return false;
 
     return axObjectForNode->isTextControl();
@@ skipping 361 matching lines @@
         if (label && label->layoutObject()) {
             LayoutRect labelRect = axObjectCache()->getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink