chrome/browser/browser_accessibility.cc

   1 // Copyright (c) 2006-2008 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/browser_accessibility.h"
   6
   7 #include "chrome/browser/browser_accessibility_manager.h"
   8 #include "chrome/browser/iaccessible_function_ids.h"
   9
  10 BrowserAccessibility::BrowserAccessibility()
  11     : iaccessible_id_(-1),
  12       instance_active_(true) {
  13 }
  14
  15 HRESULT BrowserAccessibility::accDoDefaultAction(VARIANT var_id) {
  16   if (!instance_active()) {
  17     // Instance no longer active, fail gracefully.
  18     // TODO(klink): Once we have MSAA events, change these fails for having
  19     // BrowserAccessibilityManager firing the right event.
  20     return E_FAIL;
  21   }
  22
  23   if (var_id.vt != VT_I4)
  24     return E_INVALIDARG;
  25
  26   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_ACCDODEFAULTACTION, var_id,
  27                                 NULL, NULL)) {
  28     return E_FAIL;
  29   }
  30
  31   if (!response().return_code)
  32     return S_FALSE;
  33
  34   return S_OK;
  35 }
  36
  37 STDMETHODIMP BrowserAccessibility::accHitTest(LONG x_left, LONG y_top,
  38                                               VARIANT* child) {
  39   if (!instance_active()) {
  40     // Instance no longer active, fail gracefully.
  41     return E_FAIL;
  42   }
  43
  44   if (!child)
  45     return E_INVALIDARG;
  46
  47   if (!parent_hwnd()) {
  48     // Parent HWND needed for coordinate conversion.
  49     return E_FAIL;
  50   }
  51
  52   // Convert coordinates to test from screen into client window coordinates, to
  53   // maintain sandbox functionality on renderer side.
  54   POINT p = {x_left, y_top};
  55   ::ScreenToClient(parent_hwnd(), &p);
  56
  57   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_ACCHITTEST, EmptyVariant(),
  58                                 p.x, p.y)) {
  59     return E_FAIL;
  60   }
  61
  62   if (!response().return_code) {
  63     // The point is outside of the object's boundaries.
  64     child->vt = VT_EMPTY;
  65     return S_FALSE;
  66   }
  67
  68   if (response().output_long1 == -1) {
  69     if (CreateInstance(IID_IAccessible, response().iaccessible_id,
  70                        reinterpret_cast<void**>(&child->pdispVal)) == S_OK) {
  71       child->vt = VT_DISPATCH;
  72       // Increment the reference count for the retrieved interface.
  73       child->pdispVal->AddRef();
  74     } else {
  75       return E_NOINTERFACE;
  76     }
  77   } else {
  78     child->vt = VT_I4;
  79     child->lVal = response().output_long1;
  80   }
  81
  82   return S_OK;
  83 }
  84
  85 STDMETHODIMP BrowserAccessibility::accLocation(LONG* x_left, LONG* y_top,
  86                                                LONG* width, LONG* height,
  87                                                VARIANT var_id) {
  88   if (!instance_active()) {
  89     // Instance no longer active, fail gracefully.
  90     return E_FAIL;
  91   }
  92
  93   if (var_id.vt != VT_I4 || !x_left || !y_top || !width || !height ||
  94       !parent_hwnd()) {
  95     return E_INVALIDARG;
  96   }
  97
  98   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_ACCLOCATION, var_id, NULL,
  99                                 NULL)) {
 100     return E_FAIL;
 101   }
 102
 103   POINT top_left = {0, 0};
 104
 105   // Find the top left corner of the containing window in screen coords, and
 106   // adjust the output position by this amount.
 107   ::ClientToScreen(parent_hwnd(), &top_left);
 108
 109   *x_left = response().output_long1 + top_left.x;
 110   *y_top  = response().output_long2 + top_left.y;
 111
 112   *width  = response().output_long3;
 113   *height = response().output_long4;
 114
 115   return S_OK;
 116 }
 117
 118 STDMETHODIMP BrowserAccessibility::accNavigate(LONG nav_dir, VARIANT start,
 119                                                VARIANT* end) {
 120   if (!instance_active()) {
 121     // Instance no longer active, fail gracefully.
 122     return E_FAIL;
 123   }
 124
 125   if (start.vt != VT_I4 || !end)
 126     return E_INVALIDARG;
 127
 128   if ((nav_dir == NAVDIR_LASTCHILD || nav_dir == NAVDIR_FIRSTCHILD) &&
 129       start.lVal != CHILDID_SELF) {
 130     // MSAA states that navigating to first/last child can only be from self.
 131     return E_INVALIDARG;
 132   }
 133
 134   if (nav_dir == NAVDIR_DOWN || nav_dir == NAVDIR_UP ||
 135       nav_dir == NAVDIR_LEFT || nav_dir == NAVDIR_RIGHT) {
 136     // Directions not implemented, matching Mozilla and IE.
 137     return E_INVALIDARG;
 138   }
 139
 140   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_ACCNAVIGATE, start, nav_dir,
 141                                 NULL)) {
 142     return E_FAIL;
 143   }
 144
 145   if (!response().return_code) {
 146     // No screen element was found in the specified direction.
 147     end->vt = VT_EMPTY;
 148     return S_FALSE;
 149   }
 150
 151   if (response().output_long1 == -1) {
 152     if (CreateInstance(IID_IAccessible, response().iaccessible_id,
 153                        reinterpret_cast<void**>(&end->pdispVal)) == S_OK) {
 154       end->vt = VT_DISPATCH;
 155       // Increment the reference count for the retrieved interface.
 156       end->pdispVal->AddRef();
 157     } else {
 158       return E_NOINTERFACE;
 159     }
 160   } else {
 161     end->vt = VT_I4;
 162     end->lVal = response().output_long1;
 163   }
 164
 165   return S_OK;
 166 }
 167
 168 STDMETHODIMP BrowserAccessibility::get_accChild(VARIANT var_child,
 169                                                 IDispatch** disp_child) {
 170   if (!instance_active()) {
 171     // Instance no longer active, fail gracefully.
 172     return E_FAIL;
 173   }
 174
 175   if (var_child.vt != VT_I4 || !disp_child)
 176     return E_INVALIDARG;
 177
 178   // If var_child is the parent, remain with the same IDispatch.
 179   if (var_child.lVal == CHILDID_SELF && iaccessible_id_ != 0)
 180     return S_OK;
 181
 182   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCCHILD, var_child, NULL,
 183                                 NULL)) {
 184     return E_FAIL;
 185   }
 186
 187   if (!response().return_code) {
 188     // When at a leaf, children are handled by the parent object.
 189     *disp_child = NULL;
 190     return S_FALSE;
 191   }
 192
 193   // Retrieve the IUnknown interface for the parent view, and assign the
 194   // IDispatch returned.
 195   if (CreateInstance(IID_IAccessible, response().iaccessible_id,
 196                      reinterpret_cast<void**>(disp_child)) == S_OK) {
 197     // Increment the reference count for the retrieved interface.
 198     (*disp_child)->AddRef();
 199     return S_OK;
 200   } else {
 201     return E_NOINTERFACE;
 202   }
 203 }
 204
 205 STDMETHODIMP BrowserAccessibility::get_accChildCount(LONG* child_count) {
 206   if (!instance_active()) {
 207     // Instance no longer active, fail gracefully.
 208     return E_FAIL;
 209   }
 210
 211   if (!child_count)
 212     return E_INVALIDARG;
 213
 214   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCCHILDCOUNT,
 215                                 EmptyVariant(), NULL, NULL)) {
 216     return E_FAIL;
 217   }
 218
 219   *child_count = response().output_long1;
 220   return S_OK;
 221 }
 222
 223 STDMETHODIMP BrowserAccessibility::get_accDefaultAction(VARIANT var_id,
 224                                                         BSTR* def_action) {
 225   if (!instance_active()) {
 226     // Instance no longer active, fail gracefully.
 227     return E_FAIL;
 228   }
 229
 230   if (var_id.vt != VT_I4 || !def_action)
 231     return E_INVALIDARG;
 232
 233   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCDEFAULTACTION, var_id,
 234                                 NULL, NULL)) {
 235     return E_FAIL;
 236   }
 237
 238   if (!response().return_code) {
 239     // No string found.
 240     return S_FALSE;
 241   }
 242
 243   *def_action = CComBSTR(response().output_string.c_str()).Detach();
 244
 245   DCHECK(*def_action);
 246   return S_OK;
 247 }
 248
 249 STDMETHODIMP BrowserAccessibility::get_accDescription(VARIANT var_id,
 250                                                       BSTR* desc) {
 251   if (!instance_active()) {
 252     // Instance no longer active, fail gracefully.
 253     return E_FAIL;
 254   }
 255
 256   if (var_id.vt != VT_I4 || !desc)
 257     return E_INVALIDARG;
 258
 259   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCDESCRIPTION, var_id,
 260                                 NULL, NULL)) {
 261     return E_FAIL;
 262   }
 263
 264   if (!response().return_code) {
 265     // No string found.
 266     return S_FALSE;
 267   }
 268
 269   *desc = CComBSTR(response().output_string.c_str()).Detach();
 270
 271   DCHECK(*desc);
 272   return S_OK;
 273 }
 274
 275 STDMETHODIMP BrowserAccessibility::get_accFocus(VARIANT* focus_child) {
 276   if (!instance_active()) {
 277     // Instance no longer active, fail gracefully.
 278     return E_FAIL;
 279   }
 280
 281   if (!focus_child)
 282     return E_INVALIDARG;
 283
 284   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCFOCUS, EmptyVariant(),
 285                                 NULL, NULL)) {
 286     return E_FAIL;
 287   }
 288
 289   if (!response().return_code) {
 290     // The window that contains this object is not the active window.
 291     focus_child->vt = VT_EMPTY;
 292     return S_FALSE;
 293   }
 294
 295   if (response().output_long1 == -1) {
 296     if (CreateInstance(IID_IAccessible, response().iaccessible_id,
 297            reinterpret_cast<void**>(&focus_child->pdispVal)) == S_OK) {
 298       focus_child->vt = VT_DISPATCH;
 299       // Increment the reference count for the retrieved interface.
 300       focus_child->pdispVal->AddRef();
 301     } else {
 302       return E_NOINTERFACE;
 303     }
 304   } else {
 305     focus_child->vt = VT_I4;
 306     focus_child->lVal = response().output_long1;
 307   }
 308
 309   return S_OK;
 310 }
 311
 312 STDMETHODIMP BrowserAccessibility::get_accHelp(VARIANT var_id, BSTR* help) {
 313   if (!instance_active()) {
 314     // Instance no longer active, fail gracefully.
 315     return E_FAIL;
 316   }
 317
 318   if (var_id.vt != VT_I4 || !help)
 319     return E_INVALIDARG;
 320
 321   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCHELP, var_id, NULL,
 322                                 NULL)) {
 323     return E_FAIL;
 324   }
 325
 326   if (!response().return_code) {
 327     // No string found.
 328     return S_FALSE;
 329   }
 330
 331   *help = CComBSTR(response().output_string.c_str()).Detach();
 332
 333   DCHECK(*help);
 334   return S_OK;
 335 }
 336
 337 STDMETHODIMP BrowserAccessibility::get_accKeyboardShortcut(VARIANT var_id,
 338                                                            BSTR* acc_key) {
 339   if (!instance_active()) {
 340     // Instance no longer active, fail gracefully.
 341     return E_FAIL;
 342   }
 343
 344   if (var_id.vt != VT_I4 || !acc_key)
 345     return E_INVALIDARG;
 346
 347   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCKEYBOARDSHORTCUT,
 348                                 var_id, NULL, NULL)) {
 349     return E_FAIL;
 350   }
 351
 352   if (!response().return_code) {
 353     // No string found.
 354     return S_FALSE;
 355   }
 356
 357   *acc_key = CComBSTR(response().output_string.c_str()).Detach();
 358
 359   DCHECK(*acc_key);
 360   return S_OK;
 361 }
 362
 363 STDMETHODIMP BrowserAccessibility::get_accName(VARIANT var_id, BSTR* name) {
 364   if (!instance_active()) {
 365     // Instance no longer active, fail gracefully.
 366     return E_FAIL;
 367   }
 368
 369   if (var_id.vt != VT_I4 || !name)
 370     return E_INVALIDARG;
 371
 372   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCNAME, var_id, NULL,
 373                                 NULL)) {
 374     return E_FAIL;
 375   }
 376
 377   if (!response().return_code) {
 378     // No string found.
 379     return S_FALSE;
 380   }
 381
 382   *name = CComBSTR(response().output_string.c_str()).Detach();
 383
 384   DCHECK(*name);
 385   return S_OK;
 386 }
 387
 388 STDMETHODIMP BrowserAccessibility::get_accParent(IDispatch** disp_parent) {
 389   if (!instance_active()) {
 390     // Instance no longer active, fail gracefully.
 391     return E_FAIL;
 392   }
 393
 394   if (!disp_parent || !parent_hwnd())
 395     return E_INVALIDARG;
 396
 397   // Root node's parent is the containing HWND's IAccessible.
 398   if (iaccessible_id() == 0) {
 399     // For an object that has no parent (e.g. root), point the accessible parent
 400     // to the default implementation.
 401     HRESULT hr =
 402         ::CreateStdAccessibleObject(parent_hwnd(), OBJID_WINDOW,
 403                                     IID_IAccessible,
 404                                     reinterpret_cast<void**>(disp_parent));
 405
 406     if (!SUCCEEDED(hr)) {
 407       *disp_parent = NULL;
 408       return S_FALSE;
 409     }
 410     return S_OK;
 411   }
 412
 413   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCPARENT, EmptyVariant(),
 414                                 NULL, NULL)) {
 415     return E_FAIL;
 416   }
 417
 418   if (!response().return_code) {
 419     // No parent exists for this object.
 420     return S_FALSE;
 421   }
 422
 423   // Retrieve the IUnknown interface for the parent view, and assign the
 424   // IDispatch returned.
 425   if (CreateInstance(IID_IAccessible, response().iaccessible_id,
 426                      reinterpret_cast<void**>(disp_parent)) == S_OK) {
 427     // Increment the reference count for the retrieved interface.
 428     (*disp_parent)->AddRef();
 429     return S_OK;
 430   } else {
 431     return E_NOINTERFACE;
 432   }
 433 }
 434
 435 STDMETHODIMP BrowserAccessibility::get_accRole(VARIANT var_id, VARIANT* role) {
 436   if (!instance_active()) {
 437     // Instance no longer active, fail gracefully.
 438     return E_FAIL;
 439   }
 440
 441   if (var_id.vt != VT_I4 || !role)
 442     return E_INVALIDARG;
 443
 444   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCROLE, var_id, NULL,
 445                                 NULL)) {
 446     return E_FAIL;
 447   }
 448
 449   role->vt = VT_I4;
 450   role->lVal = response().output_long1;
 451
 452   return S_OK;
 453 }
 454
 455 STDMETHODIMP BrowserAccessibility::get_accState(VARIANT var_id,
 456                                                 VARIANT* state) {
 457   if (!instance_active()) {
 458     // Instance no longer active, fail gracefully.
 459     return E_FAIL;
 460   }
 461
 462   if (var_id.vt != VT_I4 || !state)
 463     return E_INVALIDARG;
 464
 465   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCSTATE, var_id, NULL,
 466                                 NULL)) {
 467     return E_FAIL;
 468   }
 469
 470   state->vt = VT_I4;
 471   state->lVal = response().output_long1;
 472
 473   return S_OK;
 474 }
 475
 476 STDMETHODIMP BrowserAccessibility::get_accValue(VARIANT var_id, BSTR* value) {
 477   if (!instance_active()) {
 478     // Instance no longer active, fail gracefully.
 479     return E_FAIL;
 480   }
 481
 482   if (var_id.vt != VT_I4 || !value)
 483     return E_INVALIDARG;
 484
 485   if (!RequestAccessibilityInfo(IACCESSIBLE_FUNC_GET_ACCVALUE, var_id, NULL,
 486                                 NULL)) {
 487         return E_FAIL;
 488   }
 489
 490   if (!response().return_code) {
 491     // No string found.
 492     return S_FALSE;
 493   }
 494
 495   *value = CComBSTR(response().output_string.c_str()).Detach();
 496
 497   DCHECK(*value);
 498   return S_OK;
 499 }
 500
 501 STDMETHODIMP BrowserAccessibility::accSelect(LONG flags_select,
 502                                              VARIANT var_id) {
 503   return DISP_E_MEMBERNOTFOUND;
 504 }
 505
 506 STDMETHODIMP BrowserAccessibility::get_accHelpTopic(BSTR* help_file,
 507                                                     VARIANT var_id,
 508                                                     LONG* topic_id) {
 509   if (help_file) {
 510     *help_file = NULL;
 511   }
 512   if (topic_id) {
 513     *topic_id = static_cast<LONG>(-1);
 514   }
 515   return DISP_E_MEMBERNOTFOUND;
 516 }
 517
 518 STDMETHODIMP BrowserAccessibility::get_accSelection(VARIANT* selected) {
 519   if (selected)
 520     selected->vt = VT_EMPTY;
 521
 522   return DISP_E_MEMBERNOTFOUND;
 523 }
 524
 525 STDMETHODIMP BrowserAccessibility::put_accName(VARIANT var_id, BSTR put_name) {
 526   return DISP_E_MEMBERNOTFOUND;
 527 }
 528
 529 STDMETHODIMP BrowserAccessibility::put_accValue(VARIANT var_id, BSTR put_val) {
 530   return DISP_E_MEMBERNOTFOUND;
 531 }
 532
 533 STDMETHODIMP BrowserAccessibility::CreateInstance(REFIID iid,
 534                                                   int iaccessible_id,
 535                                                   void** interface_ptr) {
 536   return BrowserAccessibilityManager::GetInstance()->
 537       CreateAccessibilityInstance(iid, iaccessible_id, instance_id(),
 538                                   interface_ptr);
 539 }
 540
 541 bool BrowserAccessibility::RequestAccessibilityInfo(int iaccessible_func_id,
 542                                                     VARIANT var_id, LONG input1,
 543                                                     LONG input2) {
 544   return BrowserAccessibilityManager::GetInstance()->RequestAccessibilityInfo(
 545       iaccessible_id(), instance_id(), iaccessible_func_id, var_id, input1,
 546       input2);
 547 }
 548
 549 ViewHostMsg_Accessibility_Out_Params BrowserAccessibility::response() {
 550   return BrowserAccessibilityManager::GetInstance()->response();
 551 }
 552
 553 HWND BrowserAccessibility::parent_hwnd() {
 554   return BrowserAccessibilityManager::GetInstance()->parent_hwnd(instance_id());
 555 }
 556