content/renderer/renderer_accessibility_focus_only.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/renderer/renderer_accessibility_focus_only.h"
   6
   7 #include "content/common/accessibility_node_data.h"
   8 #include "content/renderer/render_view_impl.h"
   9 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDocument.h"
  10 #include "third_party/WebKit/Source/WebKit/chromium/public/WebElement.h"
  11 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
  12 #include "third_party/WebKit/Source/WebKit/chromium/public/WebNode.h"
  13 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
  14
  15 using WebKit::WebDocument;
  16 using WebKit::WebElement;
  17 using WebKit::WebFrame;
  18 using WebKit::WebNode;
  19 using WebKit::WebView;
  20
  21 namespace {
  22 // The root node will always have id 1. Let each child node have a new
  23 // id starting with 2.
  24 const int kInitialId = 2;
  25 }
  26
  27 namespace content {
  28
  29 RendererAccessibilityFocusOnly::RendererAccessibilityFocusOnly(
  30     RenderViewImpl* render_view)
  31     : RendererAccessibility(render_view),
  32       next_id_(kInitialId) {
  33 }
  34
  35 RendererAccessibilityFocusOnly::~RendererAccessibilityFocusOnly() {
  36 }
  37
  38 void RendererAccessibilityFocusOnly::HandleWebAccessibilityNotification(
  39     const WebKit::WebAccessibilityObject& obj,
  40     WebKit::WebAccessibilityNotification notification) {
  41   // Do nothing.
  42 }
  43
  44 void RendererAccessibilityFocusOnly::FocusedNodeChanged(const WebNode& node) {
  45   // Send the new accessible tree and post a native focus event.
  46   HandleFocusedNodeChanged(node, true);
  47 }
  48
  49 void RendererAccessibilityFocusOnly::DidFinishLoad(WebKit::WebFrame* frame) {
  50   WebView* view = render_view()->GetWebView();
  51   if (view->focusedFrame() != frame)
  52     return;
  53
  54   WebDocument document = frame->document();
  55   // Send an accessible tree to the browser, but do not post a native
  56   // focus event. This is important so that if focus is initially in an
  57   // editable text field, Windows will know to pop up the keyboard if the
  58   // user touches it and focus doesn't change.
  59   HandleFocusedNodeChanged(document.focusedNode(), false);
  60 }
  61
  62 void RendererAccessibilityFocusOnly::HandleFocusedNodeChanged(
  63     const WebNode& node,
  64     bool send_focus_event) {
  65   const WebDocument& document = GetMainDocument();
  66   if (document.isNull())
  67     return;
  68
  69   bool node_has_focus;
  70   bool node_is_editable_text;
  71   // Check HasIMETextFocus first, because it will correctly handle
  72   // focus in a text box inside a ppapi plug-in. Otherwise fall back on
  73   // checking the focused node in WebKit.
  74   if (render_view_->HasIMETextFocus()) {
  75     node_has_focus = true;
  76     node_is_editable_text = true;
  77   } else {
  78     node_has_focus = !node.isNull();
  79     node_is_editable_text =
  80         node_has_focus && render_view_->IsEditableNode(node);
  81   }
  82
  83   std::vector<AccessibilityHostMsg_NotificationParams> notifications;
  84   notifications.push_back(AccessibilityHostMsg_NotificationParams());
  85   AccessibilityHostMsg_NotificationParams& notification = notifications[0];
  86
  87   // If we want to update the browser's accessibility tree but not send a
  88   // native focus changed notification, we can send a LayoutComplete
  89   // notification, which doesn't post a native event on Windows.
  90   notification.notification_type =
  91       send_focus_event ?
  92       AccessibilityNotificationFocusChanged :
  93       AccessibilityNotificationLayoutComplete;
  94
  95   // This means that the new tree we send supercedes any previous tree,
  96   // not just a previous node.
  97   notification.includes_children = true;
  98
  99   // Set the id that the notification applies to: the root node if nothing
 100   // has focus, otherwise the focused node.
 101   notification.id = node_has_focus ? next_id_ : 1;
 102
 103   // Always include the root of the tree, the document. It always has id 1.
 104   notification.acc_tree.id = 1;
 105   notification.acc_tree.role = AccessibilityNodeData::ROLE_ROOT_WEB_AREA;
 106   notification.acc_tree.state =
 107       (1 << AccessibilityNodeData::STATE_READONLY) |
 108       (1 << AccessibilityNodeData::STATE_FOCUSABLE);
 109   if (!node_has_focus)
 110     notification.acc_tree.state |= (1 << AccessibilityNodeData::STATE_FOCUSED);
 111   notification.acc_tree.location = gfx::Rect(render_view_->size());
 112
 113   notification.acc_tree.children.push_back(AccessibilityNodeData());
 114   AccessibilityNodeData& child = notification.acc_tree.children[0];
 115   child.id = next_id_;
 116   child.role = AccessibilityNodeData::ROLE_GROUP;
 117
 118   if (!node.isNull() && node.isElementNode()) {
 119     child.location = gfx::Rect(
 120         const_cast<WebNode&>(node).to<WebElement>().boundsInViewportSpace());
 121   } else {
 122     child.location = gfx::Rect();
 123   }
 124
 125   if (node_has_focus) {
 126     child.state =
 127         (1 << AccessibilityNodeData::STATE_FOCUSABLE) |
 128         (1 << AccessibilityNodeData::STATE_FOCUSED);
 129     if (!node_is_editable_text)
 130       child.state |= (1 << AccessibilityNodeData::STATE_READONLY);
 131   }
 132
 133 #ifndef NDEBUG
 134   if (logging_) {
 135     LOG(INFO) << "Accessibility update: \n"
 136         << "routing id=" << routing_id()
 137         << " notification="
 138         << AccessibilityNotificationToString(notification.notification_type)
 139         << "\n" << notification.acc_tree.DebugString(true);
 140   }
 141 #endif
 142
 143   Send(new AccessibilityHostMsg_Notifications(routing_id(), notifications));
 144
 145   // Increment the id, wrap back when we get past a million.
 146   next_id_++;
 147   if (next_id_ > 1000000)
 148     next_id_ = kInitialId;
 149 }
 150
 151 }  // namespace content