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::AXSelection AXLayoutObject::selection() const
 {
-    if (!isTextControl())
-        return PlainTextRange();
+    AXSelection textSelection = textControlSelection();

[dmazzoni, 2015/06/16 17:24:03]

This only seems to work if *this* is a text control. Shouldn't it try to handle
the case where you call selection() on the root of the tree but a text control
has focus?

+    if (!textSelection.isNull())
+        return textSelection;
 
-    if (m_layoutObject->isTextControl()) {
-        HTMLTextFormControlElement* textControl = toLayoutTextControl(m_layoutObject)->textFormControlElement();
-        return PlainTextRange(textControl->selectionStart(), textControl->selectionEnd() - textControl->selectionStart());
+    if (!node())
+        return AXSelection();
+
+    VisibleSelection selection = visibleSelection();
+    RefPtrWillBeRawPtr<Range> selectionRange = selection.firstRange();
+    if (!selectionRange)
+        return AXSelection();
+
+    Node* anchorNode = selectionRange->startContainer();
+    ASSERT(anchorNode);
+    AXObject* anchorObject = axObjectCache()->get(anchorNode);

[dmazzoni, 2015/06/16 17:24:03]

I think you need to handle the case where this object is ignored.

As an example, if the selection start is inside an object that has
aria-hidden=true, I think we should walk up to the parent of that object and
consider the parent to be the start of the selection.

+    Node* focusNode = selectionRange->endContainer();
+    ASSERT(focusNode);
+    AXObject* focusObject = axObjectCache()->get(focusNode);
+
+    if (!anchorObject || !focusObject)
+        return AXSelection();
+
+    AXID anchorId = anchorObject->axObjectID();
+    AXID focusId = focusObject->axObjectID();
+
+    int anchorOffset = selectionRange->startOffset();
+    ASSERT(anchorOffset >= 0);
+    int focusOffset = selectionRange->endOffset();
+    ASSERT(focusOffset >= 0);
+
+    return AXSelection(
+        anchorId, static_cast<unsigned>(anchorOffset),
+        focusId, static_cast<unsigned>(focusOffset));
+}
+
+AXObject::AXSelection AXLayoutObject::selectionUnderObject() const

[dmazzoni, 2015/06/16 17:24:03]

Can you explain what this does?

+{
+    AXSelection textSelection = textControlSelection();
+    if (!textSelection.isNull())
+        return textSelection;
+
+    if (!node())
+        return AXSelection();
+
+    VisibleSelection selection = visibleSelection();
+    RefPtrWillBeRawPtr<Range> selectionRange = selection.firstRange();
+    if (!selectionRange)
+        return AXSelection();
+
+    int start = indexForVisiblePosition(selection.visibleStart());
+    int end = indexForVisiblePosition(selection.visibleEnd());
+
+    return AXSelection(start, end);
+}
+
+AXObject::AXSelection AXLayoutObject::textControlSelection() const
+{
+    if (layoutObject() && layoutObject()->isTextControl()) {
+        HTMLTextFormControlElement* textControl = toLayoutTextControl(
+            layoutObject())->textFormControlElement();
+        AXID id = axObjectID();
+        unsigned start = textControl->selectionStart();
+        unsigned end = textControl->selectionEnd();
+        return AXSelection(id, start, id, end);
     }
 
-    return visibleSelectionUnderObject();
+    return AXSelection();
 }
 
-VisibleSelection AXLayoutObject::selection() const
+VisibleSelection AXLayoutObject::visibleSelection() const
 {
-    return m_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 AXSelection& 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.hasAnchor())
+        anchorObject = axObjectCache()->objectFromAXID(selection.anchorId);
+
+    AXObject* focusObject = this;
+    if (selection.hasFocus())
+        focusObject = axObjectCache()->objectFromAXID(selection.focusId);
+
+    if (!anchorObject || !focusObject)
+        return;
+
+    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();
+    Node* focusNode = focusObject->node();
+    if (!anchorNode || !focusNode)

[dmazzoni, 2015/06/16 17:24:03]

Some objects in the tree have a layoutObject but not a node - you should maybe
walk up the parents until you find an ancestor with a node.

One example is an anonymous block, another example is CSS-generated text.

+        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,

[dmazzoni, 2015/06/16 17:24:03]

I think you need to check that both the anchorNode and focusNode are part of the
same Document or maybe the same TreeScope, since Blink doesn't let a selection
span frames.

+        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