Initial skeleton of Accessibility Object Model Phase 1

third_party/WebKit/Source/core/dom/AccessibleNode.cpp

+// Copyright 2017 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 "core/dom/AccessibleNode.h"
+
+#include "core/dom/AXObjectCache.h"
+#include "core/dom/Element.h"
+#include "core/dom/QualifiedName.h"
+#include "core/frame/Settings.h"
+
+namespace blink {
+
+AccessibleNode::AccessibleNode(Element* element) : m_element(element) {
+  DCHECK(RuntimeEnabledFeatures::accessibilityObjectModelEnabled());
+}
+
+AccessibleNode::~AccessibleNode() {}
+
+// static
+const AtomicString& AccessibleNode::getProperty(Element* element,
+                                                AOMStringProperty property) {
+  DCHECK_GE(property, AOMStringProperty::kFirst);
+  DCHECK_LT(property, AOMStringProperty::kCount);
+
+  if (AccessibleNode* accessibleNode = element->existingAccessibleNode()) {
+    unsigned propertyIndex = static_cast<unsigned>(property);
+    if (accessibleNode->m_stringPropertyDirty[propertyIndex])

[esprehn, 2017/03/24 01:59:39]

value = accessibleNode->m_stringProperties[index];
if (!value.isNull())
  return value;

+      return accessibleNode->m_stringProperties[propertyIndex];
+  }
+
+  // Fall back on the equivalent ARIA attribute.
+  switch (property) {
+    case AOMStringProperty::kRole:
+      return element->getAttribute(HTMLNames::roleAttr);
+    case AOMStringProperty::kLabel:
+      return element->getAttribute(HTMLNames::aria_labelAttr);
+    default:
+      NOTREACHED();
+      return nullAtom;
+  }
+}
+
+AtomicString AccessibleNode::role() const {
+  return getProperty(m_element, AOMStringProperty::kRole);
+}
+
+void AccessibleNode::setRole(const AtomicString& role) {
+  if (!m_element)

[esprehn, 2017/03/24 01:59:39]

How does the node still exist but the accessibleNode not exist? I don't think
that should happen if the lifetime is correct.

[dmazzoni, 2017/03/24 17:51:12]

Did you mean that backwards? The case we're guarding against here
is that the element is deleted, but there's still a reference
to the AccessibleNode.

I added a test for this that explicitly calls gc(). Without
null-checking m_element it crashes.

+    return;
+
+  const unsigned kRoleIndex = static_cast<unsigned>(AOMStringProperty::kRole);
+  m_stringProperties[kRoleIndex] = role;
+  m_stringPropertyDirty[kRoleIndex] = true;

[esprehn, 2017/03/24 01:59:39]

remove

+
+  // TODO(dmazzoni): Make a cleaner API for this rather than pretending
+  // the DOM attribute changed.
+  if (AXObjectCache* cache = m_element->document().axObjectCache())
+    cache->handleAttributeChanged(HTMLNames::roleAttr, m_element);
+}
+
+AtomicString AccessibleNode::label() const {
+  return getProperty(m_element, AOMStringProperty::kLabel);
+}
+
+void AccessibleNode::setLabel(const AtomicString& label) {
+  const unsigned kLabelIndex = static_cast<unsigned>(AOMStringProperty::kLabel);
+  m_stringProperties[kLabelIndex] = label;
+  m_stringPropertyDirty[kLabelIndex] = true;

[esprehn, 2017/03/24 01:59:39]

ditto

+
+  if (AXObjectCache* cache = m_element->document().axObjectCache())
+    cache->handleAttributeChanged(HTMLNames::aria_labelAttr, m_element);
+}
+
+DEFINE_TRACE(AccessibleNode) {
+  visitor->trace(m_element);
+}
+
+}  // namespace blink