renderer_accessibility_focus_only.cc revision 58537e28ecd584eab876aee8be7156509866d23a 
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/accessibility/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/public/web/WebDocument.h"
10#include "third_party/WebKit/public/web/WebElement.h"
11#include "third_party/WebKit/public/web/WebFrame.h"
12#include "third_party/WebKit/public/web/WebNode.h"
13#include "third_party/WebKit/public/web/WebView.h"
14
15using WebKit::WebDocument;
16using WebKit::WebElement;
17using WebKit::WebFrame;
18using WebKit::WebNode;
19using WebKit::WebView;
20
21namespace {
22// The root node will always have id 1. Let each child node have a new
23// id starting with 2.
24const int kInitialId = 2;
25}
26
27namespace content {
28
29RendererAccessibilityFocusOnly::RendererAccessibilityFocusOnly(
30    RenderViewImpl* render_view)
31    : RendererAccessibility(render_view),
32      next_id_(kInitialId) {
33}
34
35RendererAccessibilityFocusOnly::~RendererAccessibilityFocusOnly() {
36}
37
38void RendererAccessibilityFocusOnly::HandleWebAccessibilityEvent(
39    const WebKit::WebAXObject& obj, WebKit::WebAXEvent event) {
40  // Do nothing.
41}
42
43void RendererAccessibilityFocusOnly::FocusedNodeChanged(const WebNode& node) {
44  // Send the new accessible tree and post a native focus event.
45  HandleFocusedNodeChanged(node, true);
46}
47
48void RendererAccessibilityFocusOnly::DidFinishLoad(WebKit::WebFrame* frame) {
49  WebView* view = render_view()->GetWebView();
50  if (view->focusedFrame() != frame)
51    return;
52
53  WebDocument document = frame->document();
54  // Send an accessible tree to the browser, but do not post a native
55  // focus event. This is important so that if focus is initially in an
56  // editable text field, Windows will know to pop up the keyboard if the
57  // user touches it and focus doesn't change.
58  HandleFocusedNodeChanged(document.focusedNode(), false);
59}
60
61void RendererAccessibilityFocusOnly::HandleFocusedNodeChanged(
62    const WebNode& node,
63    bool send_focus_event) {
64  const WebDocument& document = GetMainDocument();
65  if (document.isNull())
66    return;
67
68  bool node_has_focus;
69  bool node_is_editable_text;
70  // Check HasIMETextFocus first, because it will correctly handle
71  // focus in a text box inside a ppapi plug-in. Otherwise fall back on
72  // checking the focused node in WebKit.
73  if (render_view_->HasIMETextFocus()) {
74    node_has_focus = true;
75    node_is_editable_text = true;
76  } else {
77    node_has_focus = !node.isNull();
78    node_is_editable_text =
79        node_has_focus && render_view_->IsEditableNode(node);
80  }
81
82  std::vector<AccessibilityHostMsg_EventParams> events;
83  events.push_back(AccessibilityHostMsg_EventParams());
84  AccessibilityHostMsg_EventParams& event = events[0];
85
86  // If we want to update the browser's accessibility tree but not send a
87  // native focus changed event, we can send a LayoutComplete
88  // event, which doesn't post a native event on Windows.
89  event.event_type =
90      send_focus_event ?
91      WebKit::WebAXEventFocus :
92      WebKit::WebAXEventLayoutComplete;
93
94  // Set the id that the event applies to: the root node if nothing
95  // has focus, otherwise the focused node.
96  event.id = node_has_focus ? next_id_ : 1;
97
98  event.nodes.resize(2);
99  AccessibilityNodeData& root = event.nodes[0];
100  AccessibilityNodeData& child = event.nodes[1];
101
102  // Always include the root of the tree, the document. It always has id 1.
103  root.id = 1;
104  root.role = WebKit::WebAXRoleRootWebArea;
105  root.state =
106      (1 << WebKit::WebAXStateReadonly) |
107      (1 << WebKit::WebAXStateFocusable);
108  if (!node_has_focus)
109    root.state |= (1 << WebKit::WebAXStateFocused);
110  root.location = gfx::Rect(render_view_->size());
111  root.child_ids.push_back(next_id_);
112
113  child.id = next_id_;
114  child.role = WebKit::WebAXRoleGroup;
115
116  if (!node.isNull() && node.isElementNode()) {
117    child.location = gfx::Rect(
118        const_cast<WebNode&>(node).to<WebElement>().boundsInViewportSpace());
119  } else if (render_view_->HasIMETextFocus()) {
120    child.location = root.location;
121  } else {
122    child.location = gfx::Rect();
123  }
124
125  if (node_has_focus) {
126    child.state =
127        (1 << WebKit::WebAXStateFocusable) |
128        (1 << WebKit::WebAXStateFocused);
129    if (!node_is_editable_text)
130      child.state |= (1 << WebKit::WebAXStateReadonly);
131  }
132
133#ifndef NDEBUG
134  if (logging_) {
135    LOG(INFO) << "Accessibility update: \n"
136        << "routing id=" << routing_id()
137        << " event="
138        << AccessibilityEventToString(event.event_type)
139        << "\n" << event.nodes[0].DebugString(true);
140  }
141#endif
142
143  Send(new AccessibilityHostMsg_Events(routing_id(), events));
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
152