Native Android accessibility.

content/browser/accessibility/browser_accessibility_android.cc

+// Copyright (c) 2013 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 "content/browser/accessibility/browser_accessibility_android.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_registrar.h"
+#include "base/android/jni_string.h"
+#include "base/utf_string_conversions.h"
+#include "content/browser/accessibility/browser_accessibility_manager_android.h"
+#include "content/common/accessibility_messages.h"
+#include "content/common/accessibility_node_data.h"
+#include "jni/BrowserAccessibility_jni.h"
+
+namespace content {
+
+// static
+BrowserAccessibility* BrowserAccessibility::Create() {
+  return new BrowserAccessibilityAndroid();
+}
+
+BrowserAccessibilityAndroid::BrowserAccessibilityAndroid() {
+  first_time_ = true;
+}
+
+bool BrowserAccessibilityAndroid::IsNative() const {
+  return true;
+}
+
+//
+// Actions, called from Java.
+//
+
+void BrowserAccessibilityAndroid::FocusJNI(JNIEnv* env, jobject obj) {
+  manager_->SetFocus(this, true);
+}
+
+void BrowserAccessibilityAndroid::ClickJNI(JNIEnv* env, jobject obj) {
+  manager_->DoDefaultAction(*this);
+}
+
+//
+// Const accessors, called from Java.
+//
+
+ScopedJavaLocalRef<jstring>
+BrowserAccessibilityAndroid::GetNameJNI(JNIEnv* env, jobject obj) const {
+  return base::android::ConvertUTF16ToJavaString(env, ComputeName());
+}
+
+ScopedJavaLocalRef<jobject>
+BrowserAccessibilityAndroid::GetAbsoluteRectJNI(JNIEnv* env, jobject obj) const {
+  gfx::Rect rect = GetLocalBoundsRect();
+
+  return Java_BrowserAccessibility_createRect(
+      env,
+      static_cast<int>(rect.x()),
+      static_cast<int>(rect.y()),
+      static_cast<int>(rect.right()),
+      static_cast<int>(rect.bottom()));
+}
+
+ScopedJavaLocalRef<jobject>
+BrowserAccessibilityAndroid::GetRectInParentJNI(JNIEnv* env, jobject obj) const {
+  gfx::Rect rect = GetLocalBoundsRect();
+  if (parent()) {
+    gfx::Rect parent_rect = parent()->GetLocalBoundsRect();
+    rect.Offset(-parent_rect.OffsetFromOrigin());
+  }
+  return Java_BrowserAccessibility_createRect(
+      env,
+      static_cast<int>(rect.x()),
+      static_cast<int>(rect.y()),
+      static_cast<int>(rect.right()),
+      static_cast<int>(rect.bottom()));
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsFocusableJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jboolean>(IsFocusable());
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsEditableTextJNI(JNIEnv* env, jobject obj) const {
+  return IsEditableText();
+}
+
+jint BrowserAccessibilityAndroid::GetParentJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jint>(parent()->renderer_id());
+}
+
+jint
+BrowserAccessibilityAndroid::GetChildCountJNI(JNIEnv* env, jobject obj) const {
+  if (IsLeaf())
+    return 0;
+  else
+    return static_cast<jint>(child_count());
+}
+
+jint BrowserAccessibilityAndroid::GetChildIdAtJNI(JNIEnv* env,
+                                               jobject obj,
+                                               jint child_index) const {
+  return static_cast<jint>(GetChild(child_index)->renderer_id());
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsCheckableJNI(JNIEnv* env, jobject obj) const {
+  bool checkable = false;
+  bool is_aria_pressed_defined;
+  bool is_mixed;
+  GetAriaTristate("aria-pressed", &is_aria_pressed_defined, &is_mixed);
+  if (role() == AccessibilityNodeData::ROLE_CHECKBOX ||
+      role() == AccessibilityNodeData::ROLE_RADIO_BUTTON ||
+      is_aria_pressed_defined) {
+    checkable = true;
+  }
+  if (HasState(AccessibilityNodeData::STATE_CHECKED))
+    checkable = true;
+  return static_cast<jboolean>(checkable);
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsCheckedJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jboolean>(
+      HasState(AccessibilityNodeData::STATE_CHECKED));
+}
+
+base::android::ScopedJavaLocalRef<jstring>
+BrowserAccessibilityAndroid::GetClassNameJNI(JNIEnv* env, jobject obj) const {
+  const char* class_name = NULL;
+
+  switch(role()) {
+    case AccessibilityNodeData::ROLE_EDITABLE_TEXT:
+    case AccessibilityNodeData::ROLE_SPIN_BUTTON:
+    case AccessibilityNodeData::ROLE_TEXTAREA:
+    case AccessibilityNodeData::ROLE_TEXT_FIELD:
+      class_name = "android.widget.EditText";
+      break;
+    case AccessibilityNodeData::ROLE_SLIDER:
+      class_name = "android.widget.SeekBar";
+      break;
+    case AccessibilityNodeData::ROLE_COMBO_BOX:
+      class_name = "android.widget.Spinner";
+      break;
+    case AccessibilityNodeData::ROLE_BUTTON:
+    case AccessibilityNodeData::ROLE_MENU_BUTTON:
+    case AccessibilityNodeData::ROLE_POPUP_BUTTON:
+      class_name = "android.widget.Button";
+      break;
+    case AccessibilityNodeData::ROLE_CHECKBOX:
+      class_name = "android.widget.CheckBox";
+      break;
+    case AccessibilityNodeData::ROLE_RADIO_BUTTON:
+      class_name = "android.widget.RadioButton";
+      break;
+    case AccessibilityNodeData::ROLE_TOGGLE_BUTTON:
+      class_name = "android.widget.ToggleButton";
+      break;
+    case AccessibilityNodeData::ROLE_CANVAS:
+    case AccessibilityNodeData::ROLE_IMAGE:
+      class_name = "android.widget.Image";
+      break;
+    case AccessibilityNodeData::ROLE_PROGRESS_INDICATOR:
+      class_name = "android.widget.ProgressBar";
+      break;
+    case AccessibilityNodeData::ROLE_TAB_LIST:
+      class_name = "android.widget.TabWidget";
+      break;
+    case AccessibilityNodeData::ROLE_GRID:
+    case AccessibilityNodeData::ROLE_TABLE:
+      class_name = "android.widget.GridView";
+      break;
+    case AccessibilityNodeData::ROLE_LIST:
+    case AccessibilityNodeData::ROLE_LISTBOX:
+      class_name = "android.widget.ListView";
+      break;
+    default:
+      class_name = "android.view.View";
+      break;
+  }
+
+  return base::android::ConvertUTF8ToJavaString(env, class_name);
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsEnabledJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jboolean>(
+      !HasState(AccessibilityNodeData::STATE_UNAVAILABLE));
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsFocusedJNI(JNIEnv* env, jobject obj) const {
+  return manager()->GetFocus(manager()->GetRoot()) == this;
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsPasswordJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jboolean>(
+      HasState(AccessibilityNodeData::STATE_PROTECTED));
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsScrollableJNI(JNIEnv* env, jobject obj) const {
+  int dummy;
+  bool scrollable = GetIntAttribute(
+      AccessibilityNodeData::ATTR_SCROLL_X_MAX, &dummy);
+  return static_cast<jboolean>(scrollable);
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsSelectedJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jboolean>(
+      HasState(AccessibilityNodeData::STATE_SELECTED));
+}
+
+jboolean
+BrowserAccessibilityAndroid::IsVisibleJNI(JNIEnv* env, jobject obj) const {
+  return static_cast<jboolean>(
+      !HasState(AccessibilityNodeData::STATE_INVISIBLE));
+}
+
+base::android::ScopedJavaLocalRef<jstring>
+BrowserAccessibilityAndroid::GetAriaLiveJNI(JNIEnv* env, jobject obj) const {
+  return base::android::ConvertUTF16ToJavaString(env, GetAriaLive());
+}
+
+jint BrowserAccessibilityAndroid::GetItemIndexJNI(JNIEnv* env, jobject obj) const {
+  int index = 0;
+  switch(role()) {
+    case AccessibilityNodeData::ROLE_LIST_ITEM:
+    case AccessibilityNodeData::ROLE_LISTBOX_OPTION:
+      index = index_in_parent();
+      break;
+    case AccessibilityNodeData::ROLE_SLIDER:
+    case AccessibilityNodeData::ROLE_PROGRESS_INDICATOR: {
+      float value_for_range;
+      if (GetFloatAttribute(
+              AccessibilityNodeData::ATTR_VALUE_FOR_RANGE, &value_for_range)) {
+        index = static_cast<int>(value_for_range);
+      }
+      break;
+    }
+  }
+  return static_cast<jint>(index);
+}
+
+jint
+BrowserAccessibilityAndroid::GetItemCountJNI(JNIEnv* env, jobject obj) const {
+  int count = 0;
+  switch(role()) {
+    case AccessibilityNodeData::ROLE_LIST:
+    case AccessibilityNodeData::ROLE_LISTBOX:
+      count = child_count();
+      break;
+    case AccessibilityNodeData::ROLE_SLIDER:
+    case AccessibilityNodeData::ROLE_PROGRESS_INDICATOR: {
+      float max_value_for_range;
+      if (GetFloatAttribute(AccessibilityNodeData::ATTR_MAX_VALUE_FOR_RANGE,
+                            &max_value_for_range)) {
+        count = static_cast<int>(max_value_for_range);
+      }
+      break;
+    }
+  }
+  return static_cast<jint>(count);
+}
+
+jint
+BrowserAccessibilityAndroid::GetScrollXJNI(JNIEnv* env, jobject obj) const {
+  int value = 0;
+  GetIntAttribute(AccessibilityNodeData::ATTR_SCROLL_X, &value);
+  return static_cast<jint>(value);
+}
+
+jint
+BrowserAccessibilityAndroid::GetScrollYJNI(JNIEnv* env, jobject obj) const {
+  int value = 0;
+  GetIntAttribute(AccessibilityNodeData::ATTR_SCROLL_Y, &value);
+  return static_cast<jint>(value);
+}
+
+jint
+BrowserAccessibilityAndroid::GetMaxScrollXJNI(JNIEnv* env, jobject obj) const {
+  int value = 0;
+  GetIntAttribute(AccessibilityNodeData::ATTR_SCROLL_X_MAX, &value);
+  return static_cast<jint>(value);
+}
+
+jint
+BrowserAccessibilityAndroid::GetMaxScrollYJNI(JNIEnv* env, jobject obj) const {
+  int value = 0;
+  GetIntAttribute(AccessibilityNodeData::ATTR_SCROLL_Y_MAX, &value);
+  return static_cast<jint>(value);
+}
+
+jboolean
+BrowserAccessibilityAndroid::GetClickableJNI(JNIEnv* env, jobject obj) const {
+  return (IsLeaf() && !ComputeName().empty());
+}
+
+jint BrowserAccessibilityAndroid::GetSelectionStartJNI(JNIEnv* env, jobject obj)
+    const {
+  int sel_start = 0;
+  GetIntAttribute(AccessibilityNodeData::ATTR_TEXT_SEL_START, &sel_start);
+  return sel_start;
+}
+
+jint BrowserAccessibilityAndroid::GetSelectionEndJNI(JNIEnv* env, jobject obj)
+    const {
+  int sel_end = 0;
+  GetIntAttribute(AccessibilityNodeData::ATTR_TEXT_SEL_END, &sel_end);
+  return sel_end;
+}
+
+jint BrowserAccessibilityAndroid::GetEditableTextLengthJNI(
+    JNIEnv* env, jobject obj) const {
+  return value().length();
+}
+
+int BrowserAccessibilityAndroid::GetTextChangeFromIndexJNI(
+    JNIEnv* env, jobject obj) const {
+  size_t index = 0;
+  while (index < old_value_.length() &&
+         index < new_value_.length() &&
+         old_value_[index] == new_value_[index]) {
+    index++;
+  }
+  return index;
+}
+
+jint BrowserAccessibilityAndroid::GetTextChangeAddedCountJNI(
+    JNIEnv* env, jobject obj) const {
+  size_t old_len = old_value_.length();
+  size_t new_len = new_value_.length();
+  size_t left = 0;
+  while (left < old_len &&
+         left < new_len &&
+         old_value_[left] == new_value_[left]) {
+    left++;
+  }
+  size_t right = 0;
+  while (right < old_len &&
+         right < new_len &&
+         old_value_[old_len - right - 1] == new_value_[new_len - right - 1]) {
+    right++;
+  }
+  return (new_len - left - right);
+}
+
+jint BrowserAccessibilityAndroid::GetTextChangeRemovedCountJNI(
+    JNIEnv* env, jobject obj) const {
+  size_t old_len = old_value_.length();
+  size_t new_len = new_value_.length();
+  size_t left = 0;
+  while (left < old_len &&
+         left < new_len &&
+         old_value_[left] == new_value_[left]) {
+    left++;
+  }
+  size_t right = 0;
+  while (right < old_len &&
+         right < new_len &&
+         old_value_[old_len - right - 1] == new_value_[new_len - right - 1]) {
+    right++;
+  }
+  return (old_len - left - right);
+}
+
+base::android::ScopedJavaLocalRef<jstring>
+BrowserAccessibilityAndroid::GetTextChangeBeforeTextJNI(
+    JNIEnv* env, jobject obj) const {
+  return base::android::ConvertUTF16ToJavaString(env, old_value_);
+}
+
+string16 BrowserAccessibilityAndroid::ComputeName() const {
+  if (IsIframe() ||
+      role() == AccessibilityNodeData::ROLE_WEB_AREA) {
+    return string16();
+  }
+
+  string16 description;
+  GetStringAttribute(AccessibilityNodeData::ATTR_DESCRIPTION,
+                           &description);
+
+  string16 text;
+  if (!name().empty())
+    text = name();
+  else if (!description.empty())
+    text = description;
+  else if (!value().empty())
+    text = value();
+
+  if (text.empty() && HasOnlyStaticTextChildren()) {
+    for (uint32 i = 0; i < child_count(); i++) {
+      BrowserAccessibility* child = GetChild(i);
+      text += static_cast<BrowserAccessibilityAndroid*>(child)->ComputeName();
+    }
+  }
+
+  switch(role()) {
+    case AccessibilityNodeData::ROLE_IMAGE_MAP_LINK:
+    case AccessibilityNodeData::ROLE_LINK:
+    case AccessibilityNodeData::ROLE_WEBCORE_LINK:
+      if (!text.empty())
+        text += ASCIIToUTF16(" ");
+      text += ASCIIToUTF16("Link");
+      break;
+    case AccessibilityNodeData::ROLE_HEADING:
+      // Only append "heading" if this node already has text.
+      if (!text.empty())
+        text += ASCIIToUTF16(" Heading");
+      break;
+  }
+
+  return text;
+}
+
+string16 BrowserAccessibilityAndroid::GetAriaLive() const {
+  string16 aria_live;
+  if (GetStringAttribute(AccessibilityNodeData::ATTR_CONTAINER_LIVE_STATUS,
+                         &aria_live)) {
+    return aria_live;
+  }
+  return string16();
+}
+
+bool BrowserAccessibilityAndroid::HasFocusableChild() const {
+  for (uint32 i = 0; i < child_count(); i++) {
+    BrowserAccessibility* child = GetChild(i);
+    if (child->HasState(AccessibilityNodeData::STATE_FOCUSABLE))
+      return true;
+    if (static_cast<BrowserAccessibilityAndroid*>(child)->HasFocusableChild())
+      return true;
+  }
+  return false;
+}
+
+bool BrowserAccessibilityAndroid::HasOnlyStaticTextChildren() const {
+  for (uint32 i = 0; i < child_count(); i++) {
+    BrowserAccessibility* child = GetChild(i);
+    if (child->role() != AccessibilityNodeData::ROLE_STATIC_TEXT)
+      return false;
+  }
+  return true;
+}
+
+bool BrowserAccessibilityAndroid::IsIframe() const {
+  string16 html_tag;
+  GetStringAttribute(AccessibilityNodeData::ATTR_HTML_TAG, &html_tag);
+  return html_tag == ASCIIToUTF16("iframe");
+}
+
+bool BrowserAccessibilityAndroid::IsFocusable() const {
+  bool focusable = HasState(AccessibilityNodeData::STATE_FOCUSABLE);
+  if (IsIframe() ||
+      role() == AccessibilityNodeData::ROLE_WEB_AREA) {
+    focusable = false;
+  }
+  return focusable;
+}
+
+bool BrowserAccessibilityAndroid::IsLeaf() const {
+  if (child_count() == 0)
+    return true;
+
+  // Iframes are always allowed to contain children.
+  if (IsIframe() ||
+      role() == AccessibilityNodeData::ROLE_ROOT_WEB_AREA ||
+      role() == AccessibilityNodeData::ROLE_WEB_AREA) {
+    return false;
+  }
+
+  // If it has a focusable child, we definitely can't leave out children.
+  if (HasFocusableChild())
+    return false;
+
+  // Headings with text can drop their children.
+  string16 name = ComputeName();
+  if (role() == AccessibilityNodeData::ROLE_HEADING && !name.empty())
+    return true;
+
+  // Focusable nodes with text can drop their children.
+  if (HasState(AccessibilityNodeData::STATE_FOCUSABLE) && !name.empty())
+    return true;
+
+  // Nodes with only static text as children can drop their children.
+  if (HasOnlyStaticTextChildren())
+    return true;
+
+  return false;
+}
+
+void BrowserAccessibilityAndroid::PostInitialize() {
+  BrowserAccessibility::PostInitialize();
+
+  if (IsEditableText()) {
+    if (value_ != new_value_) {
+      old_value_ = new_value_;
+      new_value_ = value_;
+    }
+  }
+
+  if (role_ == AccessibilityNodeData::ROLE_ALERT && first_time_)
+    manager_->NotifyAccessibilityEvent(AccessibilityNotificationAlert, this);
+
+  string16 live;
+  if (GetStringAttribute(AccessibilityNodeData::ATTR_CONTAINER_LIVE_STATUS,
+                         &live)) {
+    NotifyLiveRegionUpdate(live);
+  }
+
+  first_time_ = false;
+}
+
+void BrowserAccessibilityAndroid::NotifyLiveRegionUpdate(string16& aria_live) {
+  if (!EqualsASCII(aria_live, aria_strings::kAriaLivePolite) &&
+      !EqualsASCII(aria_live, aria_strings::kAriaLiveAssertive))
+    return;
+
+  string16 text = ComputeName();
+  if (cached_text_ != text) {
+    if (!text.empty()) {
+      manager_->NotifyAccessibilityEvent(AccessibilityNotificationObjectShow,
+                                         this);
+    }
+    cached_text_ = text;
+  }
+}
+
+bool RegisterBrowserAccessibility(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace content