posinset and setsize for input type, radio, exposed in AX tree

third_party/WebKit/Source/modules/accessibility/AXRadioInput.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+
+#include "modules/accessibility/AXRadioInput.h"
+
+#include "core/dom/ElementTraversal.h"
+#include "core/html/HTMLInputElement.h"
+#include "modules/accessibility/AXObjectCacheImpl.h"
+
+namespace blink {
+
+namespace {
+
+HTMLElement* nextElement(const HTMLElement& element, HTMLFormElement* stayWithin, bool forward)
+{
+    return forward ? Traversal<HTMLElement>::next(element, (Node* )stayWithin) : Traversal<HTMLElement>::previous(element, (Node* )stayWithin);

[dmazzoni, 2016/02/29 17:16:19]

Is it necessary to cast |stayWithin| to Node*? If it compiles without it, do
that, otherwise please use the proper C++ cast like static_cast<>, etc.

[je_julie(Not used), 2016/03/01 13:46:07]

I'll update it at next patch.

+}
+
+} // namespace
+
+using namespace HTMLNames;
+
+AXRadioInput::AXRadioInput(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
+    : AXLayoutObject(layoutObject, axObjectCache)
+{
+    // Updates posInSet and setSize for the current object and the next objects.
+    if (!calculatePosInSet())
+        return;
+    // When a new object is inserted, it needs to update setSize for the previous objects.
+    requestUpdateToNextNode(false);
+}
+
+AXRadioInput* AXRadioInput::create(LayoutObject* layoutObject, AXObjectCacheImpl& axObjectCache)
+{
+    return new AXRadioInput(layoutObject, axObjectCache);
+}
+
+void AXRadioInput::updatePosAndSetSize(int position)
+{
+    if (position)
+        m_posInSet = position;
+    m_setSize = sizeOfRadioGroup();
+}
+
+void AXRadioInput::requestUpdateToNextNode(bool forward)
+{
+    HTMLInputElement* nextElement = findNextFocusableRadioButtonInGroup(element(), forward);
+    AXObject* nextAXobject = axObjectCache().get(nextElement);
+    if (!nextAXobject || !nextAXobject->isAXRadioInput())
+        return;
+    int position = 0;
+    if (forward)

[dmazzoni, 2016/02/29 17:16:19]

What if |forward| is false, should position be posInSet() - 1?

[je_julie(Not used), 2016/03/01 13:46:07]

'requestUpdateToNextNode(false)' is only called in ctor and previous objects
will update only size, not position, as new objects are added.
If we call updatePosAndSetSize with 0, it keeps position.
I'll leave comment here at next patchset.

+        position = posInSet() + 1;
+    // It moves to backward only when a new node inserted to AX tree which already exists.
+    // it just needs update for setSize and its position is not changed.
+    toAXRadioInput(nextAXobject)->updatePosAndSetSize(position);
+    axObjectCache().postNotification(nextAXobject, AXObjectCacheImpl::AXAriaAttributeChanged);
+    toAXRadioInput(nextAXobject)->requestUpdateToNextNode(forward);
+}
+
+HTMLInputElement* AXRadioInput::findFirstFocusableRadioButtonInGroup(HTMLInputElement* current) const
+{
+    while (HTMLInputElement* prevElement = findNextFocusableRadioButtonInGroup(current, false))
+        current = prevElement;
+    return current;
+}
+
+int AXRadioInput::posInSet() const
+{
+    if (hasAttribute(aria_posinsetAttr))
+        return getAttribute(aria_posinsetAttr).toInt();
+    return m_posInSet;
+}
+
+int AXRadioInput::setSize() const
+{
+    if (hasAttribute(aria_setsizeAttr))
+        return getAttribute(aria_setsizeAttr).toInt();
+    return m_setSize;
+}
+
+bool AXRadioInput::calculatePosInSet()
+{
+    // Calculate 'posInSet' attribute when AXRadioInputs need to be updated
+    // as a new AXRadioInput Object is added or one of objects from RadioGroup is removed.
+    bool needToUpdatePrev = false;
+    int position = 1;
+    HTMLInputElement* prevElement = findNextFocusableRadioButtonInGroup(element(), false);
+    if (prevElement) {
+        AXObject* object = axObjectCache().get(prevElement);
+        // If the previous element doesn't have AXObject yet, caculate position from the first element.
+        // Otherwise, get position from the previous AXObject.
+        if (!object || !object->isAXRadioInput()) {
+            position = countFromFirstElement();
+        } else {
+            position = object->posInSet() + 1;
+            // It returns true if previous objects need to be updated.
+            // When AX tree exists already and a new node is inserted,
+            // as updating is started from the inserted node,
+            // we need to update setSize for previous nodes.
+            if (setSize() != object->setSize())
+                needToUpdatePrev = true;
+        }
+    }
+    updatePosAndSetSize(position);
+
+    // If it is not the last element, request update to the next node.
+    if (position != setSize())
+        requestUpdateToNextNode(true);
+    return needToUpdatePrev;
+}
+
+HTMLInputElement* AXRadioInput::findNextFocusableRadioButtonInGroup(HTMLInputElement* current, bool forward) const
+{
+    for (HTMLElement* htmlElement = nextElement(*current, current->form(), forward); htmlElement; htmlElement = nextElement(*htmlElement, current->form(), forward)) {
+        if (!isHTMLInputElement(*htmlElement))
+            continue;
+        HTMLInputElement* inputElement = toHTMLInputElement(htmlElement);
+        if (current->form() == inputElement->form() && inputElement->isRadioButton() && inputElement->name() == current->name())
+            return inputElement;
+    }
+    return nullptr;
+}
+
+int AXRadioInput::countFromFirstElement() const
+{
+    int count = 1;
+    HTMLInputElement* current = element();
+    while (HTMLInputElement* prevElement = findNextFocusableRadioButtonInGroup(current, false)) {
+        current = prevElement;
+        count++;
+    }
+    return count;
+}
+
+HTMLInputElement* AXRadioInput::element() const
+{
+    return toHTMLInputElement(m_layoutObject->node());
+}
+
+int AXRadioInput::sizeOfRadioGroup() const
+{
+    int size = element()->sizeOfRadioGroup();
+    // If it has no size in Group, it means that there is only itself.
+    if (!size)

[tkent, 2016/03/01 01:43:00]

Does this actually happen?

[je_julie(Not used), 2016/03/01 13:46:07]

It could happen when radio input element doesn't have name attribute and is not
grouped.

+        return 1;
+    return size;
+}
+
+} // namespace blink