src/chrome/browser/ui/views/accessibility/accessibility_event_router_views.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 "chrome/browser/ui/views/accessibility/accessibility_event_router_views.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/callback.h"
   9 #include "base/memory/singleton.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "base/strings/utf_string_conversions.h"
  12 #include "chrome/browser/accessibility/accessibility_extension_api.h"
  13 #include "chrome/browser/browser_process.h"
  14 #include "chrome/browser/chrome_notification_types.h"
  15 #include "chrome/browser/profiles/profile.h"
  16 #include "chrome/browser/profiles/profile_manager.h"
  17 #include "content/public/browser/notification_service.h"
  18 #include "ui/accessibility/ax_view_state.h"
  19 #include "ui/views/controls/menu/menu_item_view.h"
  20 #include "ui/views/controls/menu/submenu_view.h"
  21 #include "ui/views/controls/tree/tree_view.h"
  22 #include "ui/views/focus/view_storage.h"
  23 #include "ui/views/view.h"
  24 #include "ui/views/widget/widget.h"
  25
  26 using views::FocusManager;
  27
  28 AccessibilityEventRouterViews::AccessibilityEventRouterViews()
  29     : most_recent_profile_(NULL) {
  30   // Register for notification when profile is destroyed to ensure that all
  31   // observers are detatched at that time.
  32   registrar_.Add(this, chrome::NOTIFICATION_PROFILE_DESTROYED,
  33                  content::NotificationService::AllSources());
  34 }
  35
  36 AccessibilityEventRouterViews::~AccessibilityEventRouterViews() {
  37 }
  38
  39 // static
  40 AccessibilityEventRouterViews* AccessibilityEventRouterViews::GetInstance() {
  41   return Singleton<AccessibilityEventRouterViews>::get();
  42 }
  43
  44 void AccessibilityEventRouterViews::HandleAccessibilityEvent(
  45     views::View* view, ui::AXEvent event_type) {
  46   if (!ExtensionAccessibilityEventRouter::GetInstance()->
  47       IsAccessibilityEnabled()) {
  48     return;
  49   }
  50
  51   if (event_type == ui::AX_EVENT_TEXT_CHANGED ||
  52       event_type == ui::AX_EVENT_SELECTION_CHANGED) {
  53     // These two events should only be sent for views that have focus. This
  54     // enforces the invariant that we fire events triggered by user action and
  55     // not by programmatic logic. For example, the location bar can be updated
  56     // by javascript while the user focus is within some other part of the
  57     // user interface. In contrast, the other supported events here do not
  58     // depend on focus. For example, a menu within a menubar can open or close
  59     // while focus is within the location bar or anywhere else as a result of
  60     // user action. Note that the below logic can at some point be removed if
  61     // we pass more information along to the listener such as focused state.
  62     if (!view->GetFocusManager() ||
  63         view->GetFocusManager()->GetFocusedView() != view)
  64       return;
  65   }
  66
  67   // Don't dispatch the accessibility event until the next time through the
  68   // event loop, to handle cases where the view's state changes after
  69   // the call to post the event. It's safe to use base::Unretained(this)
  70   // because AccessibilityEventRouterViews is a singleton.
  71   views::ViewStorage* view_storage = views::ViewStorage::GetInstance();
  72   int view_storage_id = view_storage->CreateStorageID();
  73   view_storage->StoreView(view_storage_id, view);
  74   base::MessageLoop::current()->PostTask(
  75       FROM_HERE,
  76       base::Bind(
  77           &AccessibilityEventRouterViews::DispatchEventOnViewStorageId,
  78           view_storage_id,
  79           event_type));
  80 }
  81
  82 void AccessibilityEventRouterViews::HandleMenuItemFocused(
  83     const base::string16& menu_name,
  84     const base::string16& menu_item_name,
  85     int item_index,
  86     int item_count,
  87     bool has_submenu) {
  88   if (!ExtensionAccessibilityEventRouter::GetInstance()->
  89       IsAccessibilityEnabled()) {
  90     return;
  91   }
  92
  93   if (!most_recent_profile_)
  94     return;
  95
  96   AccessibilityMenuItemInfo info(most_recent_profile_,
  97                                  base::UTF16ToUTF8(menu_item_name),
  98                                  base::UTF16ToUTF8(menu_name),
  99                                  has_submenu,
 100                                  item_index,
 101                                  item_count);
 102   SendControlAccessibilityNotification(
 103       ui::AX_EVENT_FOCUS, &info);
 104 }
 105
 106 void AccessibilityEventRouterViews::Observe(
 107     int type,
 108     const content::NotificationSource& source,
 109     const content::NotificationDetails& details) {
 110   DCHECK_EQ(type, chrome::NOTIFICATION_PROFILE_DESTROYED);
 111   Profile* profile = content::Source<Profile>(source).ptr();
 112   if (profile == most_recent_profile_)
 113     most_recent_profile_ = NULL;
 114 }
 115
 116 //
 117 // Private methods
 118 //
 119
 120 void AccessibilityEventRouterViews::DispatchEventOnViewStorageId(
 121     int view_storage_id,
 122     ui::AXEvent type) {
 123   views::ViewStorage* view_storage = views::ViewStorage::GetInstance();
 124   views::View* view = view_storage->RetrieveView(view_storage_id);
 125   view_storage->RemoveView(view_storage_id);
 126   if (!view)
 127     return;
 128
 129   AccessibilityEventRouterViews* instance =
 130       AccessibilityEventRouterViews::GetInstance();
 131   instance->DispatchAccessibilityEvent(view, type);
 132 }
 133
 134 void AccessibilityEventRouterViews::DispatchAccessibilityEvent(
 135     views::View* view, ui::AXEvent type) {
 136   // Get the profile associated with this view. If it's not found, use
 137   // the most recent profile where accessibility events were sent, or
 138   // the default profile.
 139   Profile* profile = NULL;
 140   views::Widget* widget = view->GetWidget();
 141   if (widget) {
 142     profile = reinterpret_cast<Profile*>(
 143         widget->GetNativeWindowProperty(Profile::kProfileKey));
 144   }
 145   if (!profile)
 146     profile = most_recent_profile_;
 147   if (!profile) {
 148     if (g_browser_process->profile_manager())
 149       profile = g_browser_process->profile_manager()->GetLastUsedProfile();
 150   }
 151   if (!profile) {
 152     LOG(WARNING) << "Accessibility notification but no profile";
 153     return;
 154   }
 155
 156   most_recent_profile_ = profile;
 157
 158   if (type == ui::AX_EVENT_MENU_START ||
 159       type == ui::AX_EVENT_MENU_POPUP_START ||
 160       type == ui::AX_EVENT_MENU_END ||
 161       type == ui::AX_EVENT_MENU_POPUP_END) {
 162     SendMenuNotification(view, type, profile);
 163     return;
 164   }
 165
 166   ui::AXViewState state;
 167   view->GetAccessibleState(&state);
 168
 169   if (type == ui::AX_EVENT_ALERT &&
 170       !(state.role == ui::AX_ROLE_ALERT ||
 171         state.role == ui::AX_ROLE_WINDOW)) {
 172     SendAlertControlNotification(view, type, profile);
 173     return;
 174   }
 175
 176   switch (state.role) {
 177   case ui::AX_ROLE_ALERT:
 178   case ui::AX_ROLE_DIALOG:
 179   case ui::AX_ROLE_WINDOW:
 180     SendWindowNotification(view, type, profile);
 181     break;
 182   case ui::AX_ROLE_POP_UP_BUTTON:
 183   case ui::AX_ROLE_MENU_BAR:
 184   case ui::AX_ROLE_MENU_LIST_POPUP:
 185     SendMenuNotification(view, type, profile);
 186     break;
 187   case ui::AX_ROLE_BUTTON_DROP_DOWN:
 188   case ui::AX_ROLE_BUTTON:
 189     SendButtonNotification(view, type, profile);
 190     break;
 191   case ui::AX_ROLE_CHECK_BOX:
 192     SendCheckboxNotification(view, type, profile);
 193     break;
 194   case ui::AX_ROLE_COMBO_BOX:
 195     SendComboboxNotification(view, type, profile);
 196     break;
 197   case ui::AX_ROLE_LINK:
 198     SendLinkNotification(view, type, profile);
 199     break;
 200   case ui::AX_ROLE_LOCATION_BAR:
 201   case ui::AX_ROLE_TEXT_FIELD:
 202     SendTextfieldNotification(view, type, profile);
 203     break;
 204   case ui::AX_ROLE_MENU_ITEM:
 205     SendMenuItemNotification(view, type, profile);
 206     break;
 207   case ui::AX_ROLE_RADIO_BUTTON:
 208     // Not used anymore?
 209   case ui::AX_ROLE_SLIDER:
 210     SendSliderNotification(view, type, profile);
 211     break;
 212   case ui::AX_ROLE_TREE:
 213     SendTreeNotification(view, type, profile);
 214     break;
 215   case ui::AX_ROLE_TREE_ITEM:
 216     SendTreeItemNotification(view, type, profile);
 217     break;
 218   default:
 219     // If this is encountered, please file a bug with the role that wasn't
 220     // caught so we can add accessibility extension API support.
 221     NOTREACHED();
 222   }
 223 }
 224
 225 // static
 226 void AccessibilityEventRouterViews::SendButtonNotification(
 227     views::View* view,
 228     ui::AXEvent event,
 229     Profile* profile) {
 230   AccessibilityButtonInfo info(
 231       profile, GetViewName(view), GetViewContext(view));
 232   SendControlAccessibilityNotification(event, &info);
 233 }
 234
 235 // static
 236 void AccessibilityEventRouterViews::SendLinkNotification(
 237     views::View* view,
 238     ui::AXEvent event,
 239     Profile* profile) {
 240   AccessibilityLinkInfo info(profile, GetViewName(view), GetViewContext(view));
 241   SendControlAccessibilityNotification(event, &info);
 242 }
 243
 244 // static
 245 void AccessibilityEventRouterViews::SendMenuNotification(
 246     views::View* view,
 247     ui::AXEvent event,
 248     Profile* profile) {
 249   AccessibilityMenuInfo info(profile, GetViewName(view));
 250   SendMenuAccessibilityNotification(event, &info);
 251 }
 252
 253 // static
 254 void AccessibilityEventRouterViews::SendMenuItemNotification(
 255     views::View* view,
 256     ui::AXEvent event,
 257     Profile* profile) {
 258   std::string name = GetViewName(view);
 259   std::string context = GetViewContext(view);
 260
 261   bool has_submenu = false;
 262   int index = -1;
 263   int count = -1;
 264
 265   if (!strcmp(view->GetClassName(), views::MenuItemView::kViewClassName))
 266     has_submenu = static_cast<views::MenuItemView*>(view)->HasSubmenu();
 267
 268   views::View* parent_menu = view->parent();
 269   while (parent_menu != NULL && strcmp(parent_menu->GetClassName(),
 270                                        views::SubmenuView::kViewClassName)) {
 271     parent_menu = parent_menu->parent();
 272   }
 273   if (parent_menu) {
 274     count = 0;
 275     RecursiveGetMenuItemIndexAndCount(parent_menu, view, &index, &count);
 276   }
 277
 278   AccessibilityMenuItemInfo info(
 279       profile, name, context, has_submenu, index, count);
 280   SendControlAccessibilityNotification(event, &info);
 281 }
 282
 283 // static
 284 void AccessibilityEventRouterViews::SendTreeNotification(
 285     views::View* view,
 286     ui::AXEvent event,
 287     Profile* profile) {
 288   AccessibilityTreeInfo info(profile, GetViewName(view));
 289   SendControlAccessibilityNotification(event, &info);
 290 }
 291
 292 // static
 293 void AccessibilityEventRouterViews::SendTreeItemNotification(
 294     views::View* view,
 295     ui::AXEvent event,
 296     Profile* profile) {
 297   std::string name = GetViewName(view);
 298   std::string context = GetViewContext(view);
 299
 300   if (strcmp(view->GetClassName(), views::TreeView::kViewClassName) != 0) {
 301     NOTREACHED();
 302     return;
 303   }
 304
 305   views::TreeView* tree = static_cast<views::TreeView*>(view);
 306   ui::TreeModelNode* selected_node = tree->GetSelectedNode();
 307   ui::TreeModel* model = tree->model();
 308
 309   int siblings_count = model->GetChildCount(model->GetRoot());
 310   int children_count = -1;
 311   int index = -1;
 312   int depth = -1;
 313   bool is_expanded = false;
 314
 315   if (selected_node) {
 316     children_count = model->GetChildCount(selected_node);
 317     is_expanded = tree->IsExpanded(selected_node);
 318     ui::TreeModelNode* parent_node = model->GetParent(selected_node);
 319     if (parent_node) {
 320       index = model->GetIndexOf(parent_node, selected_node);
 321       siblings_count = model->GetChildCount(parent_node);
 322     }
 323     // Get node depth.
 324     depth = 0;
 325     while (parent_node) {
 326       depth++;
 327       parent_node = model->GetParent(parent_node);
 328     }
 329   }
 330
 331   AccessibilityTreeItemInfo info(
 332       profile, name, context, depth, index, siblings_count, children_count,
 333       is_expanded);
 334   SendControlAccessibilityNotification(event, &info);
 335 }
 336
 337 // static
 338 void AccessibilityEventRouterViews::SendTextfieldNotification(
 339     views::View* view,
 340     ui::AXEvent event,
 341     Profile* profile) {
 342   ui::AXViewState state;
 343   view->GetAccessibleState(&state);
 344   std::string name = base::UTF16ToUTF8(state.name);
 345   std::string context = GetViewContext(view);
 346   bool password = state.HasStateFlag(ui::AX_STATE_PROTECTED);
 347   AccessibilityTextBoxInfo info(profile, name, context, password);
 348   std::string value = base::UTF16ToUTF8(state.value);
 349   info.SetValue(value, state.selection_start, state.selection_end);
 350   SendControlAccessibilityNotification(event, &info);
 351 }
 352
 353 // static
 354 void AccessibilityEventRouterViews::SendComboboxNotification(
 355     views::View* view,
 356     ui::AXEvent event,
 357     Profile* profile) {
 358   ui::AXViewState state;
 359   view->GetAccessibleState(&state);
 360   std::string name = base::UTF16ToUTF8(state.name);
 361   std::string value = base::UTF16ToUTF8(state.value);
 362   std::string context = GetViewContext(view);
 363   AccessibilityComboBoxInfo info(
 364       profile, name, context, value, state.index, state.count);
 365   SendControlAccessibilityNotification(event, &info);
 366 }
 367
 368 // static
 369 void AccessibilityEventRouterViews::SendCheckboxNotification(
 370     views::View* view,
 371     ui::AXEvent event,
 372     Profile* profile) {
 373   ui::AXViewState state;
 374   view->GetAccessibleState(&state);
 375   std::string name = base::UTF16ToUTF8(state.name);
 376   std::string context = GetViewContext(view);
 377   AccessibilityCheckboxInfo info(
 378       profile,
 379       name,
 380       context,
 381       state.HasStateFlag(ui::AX_STATE_CHECKED));
 382   SendControlAccessibilityNotification(event, &info);
 383 }
 384
 385 // static
 386 void AccessibilityEventRouterViews::SendWindowNotification(
 387     views::View* view,
 388     ui::AXEvent event,
 389     Profile* profile) {
 390   ui::AXViewState state;
 391   view->GetAccessibleState(&state);
 392   std::string window_text;
 393
 394   // If it's an alert, try to get the text from the contents of the
 395   // static text, not the window title.
 396   if (state.role == ui::AX_ROLE_ALERT)
 397     window_text = RecursiveGetStaticText(view);
 398
 399   // Otherwise get it from the window's accessible name.
 400   if (window_text.empty())
 401     window_text = base::UTF16ToUTF8(state.name);
 402
 403   AccessibilityWindowInfo info(profile, window_text);
 404   SendWindowAccessibilityNotification(event, &info);
 405 }
 406
 407 // static
 408 void AccessibilityEventRouterViews::SendSliderNotification(
 409     views::View* view,
 410     ui::AXEvent event,
 411     Profile* profile) {
 412   ui::AXViewState state;
 413   view->GetAccessibleState(&state);
 414
 415   std::string name = base::UTF16ToUTF8(state.name);
 416   std::string value = base::UTF16ToUTF8(state.value);
 417   std::string context = GetViewContext(view);
 418   AccessibilitySliderInfo info(
 419       profile,
 420       name,
 421       context,
 422       value);
 423   SendControlAccessibilityNotification(event, &info);
 424 }
 425
 426 // static
 427 void AccessibilityEventRouterViews::SendAlertControlNotification(
 428     views::View* view,
 429     ui::AXEvent event,
 430     Profile* profile) {
 431   ui::AXViewState state;
 432   view->GetAccessibleState(&state);
 433
 434   std::string name = base::UTF16ToUTF8(state.name);
 435   AccessibilityAlertInfo info(
 436       profile,
 437       name);
 438   SendControlAccessibilityNotification(event, &info);
 439 }
 440
 441 // static
 442 std::string AccessibilityEventRouterViews::GetViewName(views::View* view) {
 443   ui::AXViewState state;
 444   view->GetAccessibleState(&state);
 445   return base::UTF16ToUTF8(state.name);
 446 }
 447
 448 // static
 449 std::string AccessibilityEventRouterViews::GetViewContext(views::View* view) {
 450   for (views::View* parent = view->parent();
 451        parent;
 452        parent = parent->parent()) {
 453     ui::AXViewState state;
 454     parent->GetAccessibleState(&state);
 455
 456     // Two cases are handled right now. More could be added in the future
 457     // depending on how the UI evolves.
 458
 459     // A control inside of alert, toolbar or dialog should use that container's
 460     // accessible name.
 461     if ((state.role == ui::AX_ROLE_ALERT ||
 462          state.role == ui::AX_ROLE_DIALOG ||
 463          state.role == ui::AX_ROLE_TOOLBAR) &&
 464         !state.name.empty()) {
 465       return base::UTF16ToUTF8(state.name);
 466     }
 467
 468     // A control inside of an alert or dialog (including an infobar)
 469     // should grab the first static text descendant as the context;
 470     // that's the prompt.
 471     if (state.role == ui::AX_ROLE_ALERT ||
 472         state.role == ui::AX_ROLE_DIALOG) {
 473       views::View* static_text_child = FindDescendantWithAccessibleRole(
 474           parent, ui::AX_ROLE_STATIC_TEXT);
 475       if (static_text_child) {
 476         ui::AXViewState state;
 477         static_text_child->GetAccessibleState(&state);
 478         if (!state.name.empty())
 479           return base::UTF16ToUTF8(state.name);
 480       }
 481       return std::string();
 482     }
 483   }
 484
 485   return std::string();
 486 }
 487
 488 // static
 489 views::View* AccessibilityEventRouterViews::FindDescendantWithAccessibleRole(
 490     views::View* view, ui::AXRole role) {
 491   ui::AXViewState state;
 492   view->GetAccessibleState(&state);
 493   if (state.role == role)
 494     return view;
 495
 496   for (int i = 0; i < view->child_count(); i++) {
 497     views::View* child = view->child_at(i);
 498     views::View* result = FindDescendantWithAccessibleRole(child, role);
 499     if (result)
 500       return result;
 501   }
 502
 503   return NULL;
 504 }
 505
 506 // static
 507 void AccessibilityEventRouterViews::RecursiveGetMenuItemIndexAndCount(
 508     views::View* menu,
 509     views::View* item,
 510     int* index,
 511     int* count) {
 512   for (int i = 0; i < menu->child_count(); ++i) {
 513     views::View* child = menu->child_at(i);
 514     if (!child->visible())
 515       continue;
 516
 517     int previous_count = *count;
 518     RecursiveGetMenuItemIndexAndCount(child, item, index, count);
 519     ui::AXViewState state;
 520     child->GetAccessibleState(&state);
 521     if (state.role == ui::AX_ROLE_MENU_ITEM &&
 522         *count == previous_count) {
 523       if (item == child)
 524         *index = *count;
 525       (*count)++;
 526     } else if (state.role == ui::AX_ROLE_BUTTON) {
 527       if (item == child)
 528         *index = *count;
 529       (*count)++;
 530     }
 531   }
 532 }
 533
 534 // static
 535 std::string AccessibilityEventRouterViews::RecursiveGetStaticText(
 536     views::View* view) {
 537   ui::AXViewState state;
 538   view->GetAccessibleState(&state);
 539   if (state.role == ui::AX_ROLE_STATIC_TEXT)
 540     return base::UTF16ToUTF8(state.name);
 541
 542   for (int i = 0; i < view->child_count(); ++i) {
 543     views::View* child = view->child_at(i);
 544     std::string result = RecursiveGetStaticText(child);
 545     if (!result.empty())
 546       return result;
 547   }
 548   return std::string();
 549 }