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

Source/modules/accessibility/AXLayoutObject.cpp

Index: Source/modules/accessibility/AXLayoutObject.cpp
diff --git a/Source/modules/accessibility/AXLayoutObject.cpp b/Source/modules/accessibility/AXLayoutObject.cpp
index 63b98a2f16d6dff009536f948c0fd6faf42f08b4..1a109b3f13a590651099e7e5e24cc1ca26f39a21 100644
--- a/Source/modules/accessibility/AXLayoutObject.cpp
+++ b/Source/modules/accessibility/AXLayoutObject.cpp
@@ -1834,46 +1834,165 @@ Widget* AXLayoutObject::widgetForAttachmentView() const
 }
 
 //
-// 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();
 
-    return visibleSelectionUnderObject();
+    int anchorOffset = selectionRange->startOffset();
+    ASSERT(anchorOffset >= 0);
+    int focusOffset = selectionRange->endOffset();
+    ASSERT(focusOffset >= 0);
+
+    return AXRange(
+        anchorObject, anchorOffset,
+        focusObject, focusOffset);
 }
 
-VisibleSelection AXLayoutObject::selection() const
+// 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
 {
-    return m_layoutObject->frame()->selection().selection();
+    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);
+    }
+
+    if (!node())
+        return 0;
+
+    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)
@@ -2008,33 +2127,6 @@ VisiblePosition AXLayoutObject::visiblePositionForIndex(int index) const
     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();
@@ -2116,23 +2208,6 @@ void AXLayoutObject::ariaListboxSelectedChildren(AccessibilityChildrenVector& re
     }
 }
 
-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)