accessible/src/msaa/nsAccessNodeWrap.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 2003
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Original Author: Aaron Leventhal (aaronl@netscape.com)
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
  27  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #include "nsAccessNodeWrap.h"
  40 #include "ISimpleDOMNode_i.c"
  41 #include "nsAccessibilityAtoms.h"
  42 #include "nsIAccessibilityService.h"
  43 #include "nsIAccessible.h"
  44 #include "nsAttrName.h"
  45 #include "nsIDocument.h"
  46 #include "nsIDOMCSSStyleDeclaration.h"
  47 #include "nsIDOMNodeList.h"
  48 #include "nsIDOMNSHTMLElement.h"
  49 #include "nsIDOMViewCSS.h"
  50 #include "nsIFrame.h"
  51 #include "nsINameSpaceManager.h"
  52 #include "nsIPrefService.h"
  53 #include "nsIPrefBranch.h"
  54 #include "nsIPresShell.h"
  55 #include "nsPIDOMWindow.h"
  56 #include "nsRootAccessible.h"
  57 #include "nsIServiceManager.h"
  58 #include "AccessibleApplication.h"
  59 #include "nsApplicationAccessibleWrap.h"
  60
  61 /// the accessible library and cached methods
  62 HINSTANCE nsAccessNodeWrap::gmAccLib = nsnull;
  63 HINSTANCE nsAccessNodeWrap::gmUserLib = nsnull;
  64 LPFNACCESSIBLEOBJECTFROMWINDOW nsAccessNodeWrap::gmAccessibleObjectFromWindow = nsnull;
  65 LPFNNOTIFYWINEVENT nsAccessNodeWrap::gmNotifyWinEvent = nsnull;
  66 LPFNGETGUITHREADINFO nsAccessNodeWrap::gmGetGUIThreadInfo = nsnull;
  67
  68 PRBool nsAccessNodeWrap::gIsEnumVariantSupportDisabled = 0;
  69 // Used to determine whether an IAccessible2 compatible screen reader is loaded.
  70 PRBool nsAccessNodeWrap::gIsIA2Disabled = PR_FALSE;
  71
  72 nsIAccessibleTextChangeEvent *nsAccessNodeWrap::gTextEvent = nsnull;
  73
  74 // Pref to disallow CtrlTab preview functionality if JAWS or Window-Eyes are
  75 // running.
  76 #define CTRLTAB_DISALLOW_FOR_SCREEN_READERS_PREF "browser.ctrlTab.disallowForScreenReaders"
  77
  78
  79 /* For documentation of the accessibility architecture,
  80  * see http://lxr.mozilla.org/seamonkey/source/accessible/accessible-docs.html
  81  */
  82
  83 /*
  84  * Class nsAccessNodeWrap
  85  */
  86
  87 //-----------------------------------------------------
  88 // construction
  89 //-----------------------------------------------------
  90
  91 nsAccessNodeWrap::nsAccessNodeWrap(nsIDOMNode *aNode, nsIWeakReference* aShell):
  92   nsAccessNode(aNode, aShell)
  93 {
  94 }
  95
  96 //-----------------------------------------------------
  97 // destruction
  98 //-----------------------------------------------------
  99 nsAccessNodeWrap::~nsAccessNodeWrap()
 100 {
 101 }
 102
 103 //-----------------------------------------------------
 104 // nsISupports methods
 105 //-----------------------------------------------------
 106
 107 NS_IMPL_ISUPPORTS_INHERITED1(nsAccessNodeWrap, nsAccessNode, nsIWinAccessNode);
 108
 109 //-----------------------------------------------------
 110 // nsIWinAccessNode methods
 111 //-----------------------------------------------------
 112
 113 NS_IMETHODIMP
 114 nsAccessNodeWrap::QueryNativeInterface(REFIID aIID, void** aInstancePtr)
 115 {
 116   return QueryInterface(aIID, aInstancePtr);
 117 }
 118
 119 //-----------------------------------------------------
 120 // IUnknown interface methods - see iunknown.h for documentation
 121 //-----------------------------------------------------
 122
 123 STDMETHODIMP nsAccessNodeWrap::QueryInterface(REFIID iid, void** ppv)
 124 {
 125   *ppv = nsnull;
 126
 127   if (IID_IUnknown == iid || IID_ISimpleDOMNode == iid)
 128     *ppv = static_cast<ISimpleDOMNode*>(this);
 129
 130   if (nsnull == *ppv)
 131     return E_NOINTERFACE;      //iid not supported.
 132
 133   (reinterpret_cast<IUnknown*>(*ppv))->AddRef();
 134   return S_OK;
 135 }
 136
 137 STDMETHODIMP
 138 nsAccessNodeWrap::QueryService(REFGUID guidService, REFIID iid, void** ppv)
 139 {
 140   // Can get to IAccessibleApplication from any node via QS
 141   if (iid == IID_IAccessibleApplication) {
 142     nsRefPtr<nsApplicationAccessibleWrap> app =
 143       GetApplicationAccessible();
 144     nsresult rv = app->QueryNativeInterface(iid, ppv);
 145     return NS_SUCCEEDED(rv) ? S_OK : E_NOINTERFACE;
 146   }
 147
 148   /**
 149    * To get an ISimpleDOMNode, ISimpleDOMDocument, ISimpleDOMText
 150    * or any IAccessible2 interface on should use IServiceProvider like this:
 151    * -----------------------------------------------------------------------
 152    * ISimpleDOMDocument *pAccDoc = NULL;
 153    * IServiceProvider *pServProv = NULL;
 154    * pAcc->QueryInterface(IID_IServiceProvider, (void**)&pServProv);
 155    * if (pServProv) {
 156    *   const GUID unused;
 157    *   pServProv->QueryService(unused, IID_ISimpleDOMDocument, (void**)&pAccDoc);
 158    *   pServProv->Release();
 159    * }
 160    */
 161
 162   return QueryInterface(iid, ppv);
 163 }
 164
 165 //-----------------------------------------------------
 166 // ISimpleDOMNode methods
 167 //-----------------------------------------------------
 168
 169 STDMETHODIMP nsAccessNodeWrap::get_nodeInfo(
 170     /* [out] */ BSTR __RPC_FAR *aNodeName,
 171     /* [out] */ short __RPC_FAR *aNameSpaceID,
 172     /* [out] */ BSTR __RPC_FAR *aNodeValue,
 173     /* [out] */ unsigned int __RPC_FAR *aNumChildren,
 174     /* [out] */ unsigned int __RPC_FAR *aUniqueID,
 175     /* [out] */ unsigned short __RPC_FAR *aNodeType)
 176 {
 177 __try{
 178   *aNodeName = nsnull;
 179   *aNodeValue = nsnull;
 180
 181   if (!mDOMNode)
 182     return E_FAIL;
 183
 184   nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
 185
 186   PRUint16 nodeType = 0;
 187   mDOMNode->GetNodeType(&nodeType);
 188   *aNodeType=static_cast<unsigned short>(nodeType);
 189
 190   if (*aNodeType !=  NODETYPE_TEXT) {
 191     nsAutoString nodeName;
 192     mDOMNode->GetNodeName(nodeName);
 193     *aNodeName =   ::SysAllocString(nodeName.get());
 194   }
 195
 196   nsAutoString nodeValue;
 197
 198   mDOMNode->GetNodeValue(nodeValue);
 199   *aNodeValue = ::SysAllocString(nodeValue.get());
 200   *aNameSpaceID = content ? static_cast<short>(content->GetNameSpaceID()) : 0;
 201
 202   // This is a unique ID for every content node.  The 3rd party
 203   // accessibility application can compare this to the childID we
 204   // return for events such as focus events, to correlate back to
 205   // data nodes in their internal object model.
 206   void *uniqueID;
 207   GetUniqueID(&uniqueID);
 208   *aUniqueID = - NS_PTR_TO_INT32(uniqueID);
 209
 210   *aNumChildren = 0;
 211   PRUint32 numChildren = 0;
 212   nsCOMPtr<nsIDOMNodeList> nodeList;
 213   mDOMNode->GetChildNodes(getter_AddRefs(nodeList));
 214   if (nodeList && NS_OK == nodeList->GetLength(&numChildren))
 215     *aNumChildren = static_cast<unsigned int>(numChildren);
 216
 217 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 218   return S_OK;
 219 }
 220
 221
 222
 223 STDMETHODIMP nsAccessNodeWrap::get_attributes(
 224     /* [in] */ unsigned short aMaxAttribs,
 225     /* [length_is][size_is][out] */ BSTR __RPC_FAR *aAttribNames,
 226     /* [length_is][size_is][out] */ short __RPC_FAR *aNameSpaceIDs,
 227     /* [length_is][size_is][out] */ BSTR __RPC_FAR *aAttribValues,
 228     /* [out] */ unsigned short __RPC_FAR *aNumAttribs)
 229 {
 230 __try{
 231   *aNumAttribs = 0;
 232
 233   nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
 234   if (!content)
 235     return E_FAIL;
 236
 237   PRUint32 numAttribs = content->GetAttrCount();
 238
 239   if (numAttribs > aMaxAttribs)
 240     numAttribs = aMaxAttribs;
 241   *aNumAttribs = static_cast<unsigned short>(numAttribs);
 242
 243   for (PRUint32 index = 0; index < numAttribs; index++) {
 244     aNameSpaceIDs[index] = 0; aAttribValues[index] = aAttribNames[index] = nsnull;
 245     nsAutoString attributeValue;
 246     const char *pszAttributeName;
 247
 248     const nsAttrName* name = content->GetAttrNameAt(index);
 249     aNameSpaceIDs[index] = static_cast<short>(name->NamespaceID());
 250     name->LocalName()->GetUTF8String(&pszAttributeName);
 251     aAttribNames[index] = ::SysAllocString(NS_ConvertUTF8toUTF16(pszAttributeName).get());
 252     content->GetAttr(name->NamespaceID(), name->LocalName(), attributeValue);
 253     aAttribValues[index] = ::SysAllocString(attributeValue.get());
 254   }
 255 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 256
 257   return S_OK;
 258 }
 259
 260
 261 STDMETHODIMP nsAccessNodeWrap::get_attributesForNames(
 262     /* [in] */ unsigned short aNumAttribs,
 263     /* [length_is][size_is][in] */ BSTR __RPC_FAR *aAttribNames,
 264     /* [length_is][size_is][in] */ short __RPC_FAR *aNameSpaceID,
 265     /* [length_is][size_is][retval] */ BSTR __RPC_FAR *aAttribValues)
 266 {
 267 __try {
 268   nsCOMPtr<nsIDOMElement> domElement(do_QueryInterface(mDOMNode));
 269   nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
 270
 271   if (!domElement || !content)
 272     return E_FAIL;
 273
 274   if (!content->GetDocument())
 275     return E_FAIL;
 276
 277   nsCOMPtr<nsINameSpaceManager> nameSpaceManager =
 278     do_GetService(NS_NAMESPACEMANAGER_CONTRACTID);
 279
 280   PRInt32 index;
 281
 282   for (index = 0; index < aNumAttribs; index++) {
 283     aAttribValues[index] = nsnull;
 284     if (aAttribNames[index]) {
 285       nsAutoString attributeValue, nameSpaceURI;
 286       nsAutoString attributeName(nsDependentString(static_cast<PRUnichar*>(aAttribNames[index])));
 287       nsresult rv;
 288
 289       if (aNameSpaceID[index]>0 &&
 290         NS_SUCCEEDED(nameSpaceManager->GetNameSpaceURI(aNameSpaceID[index], nameSpaceURI)))
 291           rv = domElement->GetAttributeNS(nameSpaceURI, attributeName, attributeValue);
 292       else
 293         rv = domElement->GetAttribute(attributeName, attributeValue);
 294
 295       if (NS_SUCCEEDED(rv))
 296         aAttribValues[index] = ::SysAllocString(attributeValue.get());
 297     }
 298   }
 299 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 300
 301   return S_OK;
 302 }
 303
 304 /* To do: use media type if not null */
 305 STDMETHODIMP nsAccessNodeWrap::get_computedStyle(
 306     /* [in] */ unsigned short aMaxStyleProperties,
 307     /* [in] */ boolean aUseAlternateView,
 308     /* [length_is][size_is][out] */ BSTR __RPC_FAR *aStyleProperties,
 309     /* [length_is][size_is][out] */ BSTR __RPC_FAR *aStyleValues,
 310     /* [out] */ unsigned short __RPC_FAR *aNumStyleProperties)
 311 {
 312 __try{
 313   *aNumStyleProperties = 0;
 314
 315   if (IsDefunct())
 316     return E_FAIL;
 317
 318   nsCOMPtr<nsIDOMCSSStyleDeclaration> cssDecl;
 319   nsCoreUtils::GetComputedStyleDeclaration(EmptyString(), mDOMNode,
 320                                            getter_AddRefs(cssDecl));
 321   NS_ENSURE_TRUE(cssDecl, E_FAIL);
 322
 323   PRUint32 length;
 324   cssDecl->GetLength(&length);
 325
 326   PRUint32 index, realIndex;
 327   for (index = realIndex = 0; index < length && realIndex < aMaxStyleProperties; index ++) {
 328     nsAutoString property, value;
 329     if (NS_SUCCEEDED(cssDecl->Item(index, property)) && property.CharAt(0) != '-')  // Ignore -moz-* properties
 330       cssDecl->GetPropertyValue(property, value);  // Get property value
 331     if (!value.IsEmpty()) {
 332       aStyleProperties[realIndex] =   ::SysAllocString(property.get());
 333       aStyleValues[realIndex]     =   ::SysAllocString(value.get());
 334       ++realIndex;
 335     }
 336   }
 337   *aNumStyleProperties = static_cast<unsigned short>(realIndex);
 338 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 339
 340   return S_OK;
 341 }
 342
 343
 344 STDMETHODIMP nsAccessNodeWrap::get_computedStyleForProperties(
 345     /* [in] */ unsigned short aNumStyleProperties,
 346     /* [in] */ boolean aUseAlternateView,
 347     /* [length_is][size_is][in] */ BSTR __RPC_FAR *aStyleProperties,
 348     /* [length_is][size_is][out] */ BSTR __RPC_FAR *aStyleValues)
 349 {
 350 __try {
 351   if (IsDefunct())
 352     return E_FAIL;
 353
 354   nsCOMPtr<nsIDOMCSSStyleDeclaration> cssDecl;
 355   nsCoreUtils::GetComputedStyleDeclaration(EmptyString(), mDOMNode,
 356                                            getter_AddRefs(cssDecl));
 357   NS_ENSURE_TRUE(cssDecl, E_FAIL);
 358
 359   PRUint32 index;
 360   for (index = 0; index < aNumStyleProperties; index ++) {
 361     nsAutoString value;
 362     if (aStyleProperties[index])
 363       cssDecl->GetPropertyValue(nsDependentString(static_cast<PRUnichar*>(aStyleProperties[index])), value);  // Get property value
 364     aStyleValues[index] = ::SysAllocString(value.get());
 365   }
 366 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 367
 368   return S_OK;
 369 }
 370
 371 STDMETHODIMP nsAccessNodeWrap::scrollTo(/* [in] */ boolean aScrollTopLeft)
 372 {
 373 __try {
 374   PRUint32 scrollType =
 375     aScrollTopLeft ? nsIAccessibleScrollType::SCROLL_TYPE_TOP_LEFT :
 376                      nsIAccessibleScrollType::SCROLL_TYPE_BOTTOM_RIGHT;
 377
 378   nsresult rv = ScrollTo(scrollType);
 379   if (NS_SUCCEEDED(rv))
 380     return S_OK;
 381 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 382
 383   return E_FAIL;
 384 }
 385
 386 ISimpleDOMNode* nsAccessNodeWrap::MakeAccessNode(nsIDOMNode *node)
 387 {
 388   if (!node)
 389     return NULL;
 390
 391   nsAccessNodeWrap *newNode = NULL;
 392
 393   nsCOMPtr<nsIContent> content(do_QueryInterface(node));
 394   nsCOMPtr<nsIDocument> doc;
 395
 396   if (content)
 397     doc = content->GetDocument();
 398   else {
 399     // Get the document via QueryInterface, since there is no content node
 400     doc = do_QueryInterface(node);
 401     content = do_QueryInterface(node);
 402   }
 403
 404   if (!doc)
 405     return NULL;
 406
 407   nsCOMPtr<nsIAccessibilityService> accService(do_GetService("@mozilla.org/accessibilityService;1"));
 408   if (!accService)
 409     return NULL;
 410
 411   ISimpleDOMNode *iNode = NULL;
 412   nsCOMPtr<nsIAccessible> nsAcc;
 413   accService->GetAccessibleInWeakShell(node, mWeakShell, getter_AddRefs(nsAcc));
 414   if (nsAcc) {
 415     nsCOMPtr<nsIAccessNode> accessNode(do_QueryInterface(nsAcc));
 416     NS_ASSERTION(accessNode, "nsIAccessible impl does not inherit from nsIAccessNode");
 417     IAccessible *msaaAccessible;
 418     nsAcc->GetNativeInterface((void**)&msaaAccessible); // addrefs
 419     msaaAccessible->QueryInterface(IID_ISimpleDOMNode, (void**)&iNode); // addrefs
 420     msaaAccessible->Release(); // Release IAccessible
 421   }
 422   else {
 423     newNode = new nsAccessNodeWrap(node, mWeakShell);
 424     if (!newNode)
 425       return NULL;
 426
 427     newNode->Init();
 428     iNode = static_cast<ISimpleDOMNode*>(newNode);
 429     iNode->AddRef();
 430   }
 431
 432   return iNode;
 433 }
 434
 435
 436 STDMETHODIMP nsAccessNodeWrap::get_parentNode(ISimpleDOMNode __RPC_FAR *__RPC_FAR *aNode)
 437 {
 438 __try {
 439   if (!mDOMNode)
 440     return E_FAIL;
 441
 442   nsCOMPtr<nsIDOMNode> node;
 443   mDOMNode->GetParentNode(getter_AddRefs(node));
 444   *aNode = MakeAccessNode(node);
 445 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 446
 447   return S_OK;
 448 }
 449
 450 STDMETHODIMP nsAccessNodeWrap::get_firstChild(ISimpleDOMNode __RPC_FAR *__RPC_FAR *aNode)
 451 {
 452 __try {
 453   if (!mDOMNode)
 454     return E_FAIL;
 455
 456   nsCOMPtr<nsIDOMNode> node;
 457   mDOMNode->GetFirstChild(getter_AddRefs(node));
 458   *aNode = MakeAccessNode(node);
 459 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 460
 461   return S_OK;
 462 }
 463
 464 STDMETHODIMP nsAccessNodeWrap::get_lastChild(ISimpleDOMNode __RPC_FAR *__RPC_FAR *aNode)
 465 {
 466   __try {
 467   if (!mDOMNode)
 468     return E_FAIL;
 469
 470   nsCOMPtr<nsIDOMNode> node;
 471   mDOMNode->GetLastChild(getter_AddRefs(node));
 472   *aNode = MakeAccessNode(node);
 473 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 474
 475   return S_OK;
 476 }
 477
 478 STDMETHODIMP nsAccessNodeWrap::get_previousSibling(ISimpleDOMNode __RPC_FAR *__RPC_FAR *aNode)
 479 {
 480 __try {
 481   if (!mDOMNode)
 482     return E_FAIL;
 483
 484   nsCOMPtr<nsIDOMNode> node;
 485   mDOMNode->GetPreviousSibling(getter_AddRefs(node));
 486   *aNode = MakeAccessNode(node);
 487 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 488
 489   return S_OK;
 490 }
 491
 492 STDMETHODIMP nsAccessNodeWrap::get_nextSibling(ISimpleDOMNode __RPC_FAR *__RPC_FAR *aNode)
 493 {
 494 __try {
 495   if (!mDOMNode)
 496     return E_FAIL;
 497
 498   nsCOMPtr<nsIDOMNode> node;
 499   mDOMNode->GetNextSibling(getter_AddRefs(node));
 500   *aNode = MakeAccessNode(node);
 501 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 502
 503   return S_OK;
 504 }
 505
 506 STDMETHODIMP
 507 nsAccessNodeWrap::get_childAt(unsigned aChildIndex,
 508                               ISimpleDOMNode __RPC_FAR *__RPC_FAR *aNode)
 509 {
 510 __try {
 511   *aNode = nsnull;
 512
 513   nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
 514   if (!content)
 515     return E_FAIL;  // Node already shut down
 516
 517   nsCOMPtr<nsIDOMNode> node =
 518     do_QueryInterface(content->GetChildAt(aChildIndex));
 519
 520   if (!node)
 521     return E_FAIL; // No such child
 522
 523   *aNode = MakeAccessNode(node);
 524 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 525
 526   return S_OK;
 527 }
 528
 529 STDMETHODIMP
 530 nsAccessNodeWrap::get_innerHTML(BSTR __RPC_FAR *aInnerHTML)
 531 {
 532 __try {
 533   *aInnerHTML = nsnull;
 534
 535   nsCOMPtr<nsIDOMNSHTMLElement> domNSElement(do_QueryInterface(mDOMNode));
 536   if (!domNSElement)
 537     return E_FAIL; // Node already shut down
 538
 539   nsAutoString innerHTML;
 540   domNSElement->GetInnerHTML(innerHTML);
 541   if (innerHTML.IsEmpty())
 542     return S_FALSE;
 543
 544   *aInnerHTML = ::SysAllocStringLen(innerHTML.get(), innerHTML.Length());
 545   if (!*aInnerHTML)
 546     return E_OUTOFMEMORY;
 547
 548 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 549
 550   return S_OK;
 551 }
 552
 553 STDMETHODIMP
 554 nsAccessNodeWrap::get_language(BSTR __RPC_FAR *aLanguage)
 555 {
 556 __try {
 557   *aLanguage = NULL;
 558
 559   nsAutoString language;
 560   if (NS_FAILED(GetLanguage(language))) {
 561     return E_FAIL;
 562   }
 563
 564   if (language.IsEmpty())
 565     return S_FALSE;
 566
 567   *aLanguage = ::SysAllocStringLen(language.get(), language.Length());
 568   if (!*aLanguage)
 569     return E_OUTOFMEMORY;
 570
 571 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 572
 573   return S_OK;
 574 }
 575
 576 STDMETHODIMP
 577 nsAccessNodeWrap::get_localInterface(
 578     /* [out] */ void __RPC_FAR *__RPC_FAR *localInterface)
 579 {
 580 __try {
 581   *localInterface = static_cast<nsIAccessNode*>(this);
 582   NS_ADDREF_THIS();
 583 } __except(FilterA11yExceptions(::GetExceptionCode(), GetExceptionInformation())) { }
 584   return S_OK;
 585 }
 586
 587 void nsAccessNodeWrap::InitAccessibility()
 588 {
 589   if (gIsAccessibilityActive) {
 590     return;
 591   }
 592
 593   nsCOMPtr<nsIPrefBranch> prefBranch(do_GetService(NS_PREFSERVICE_CONTRACTID));
 594   if (prefBranch) {
 595     prefBranch->GetBoolPref("accessibility.disableenumvariant", &gIsEnumVariantSupportDisabled);
 596   }
 597
 598   if (!gmUserLib) {
 599     gmUserLib =::LoadLibraryW(L"USER32.DLL");
 600   }
 601
 602   if (gmUserLib) {
 603     if (!gmNotifyWinEvent)
 604       gmNotifyWinEvent = (LPFNNOTIFYWINEVENT)GetProcAddress(gmUserLib,"NotifyWinEvent");
 605     if (!gmGetGUIThreadInfo)
 606       gmGetGUIThreadInfo = (LPFNGETGUITHREADINFO)GetProcAddress(gmUserLib,"GetGUIThreadInfo");
 607   }
 608
 609   DoATSpecificProcessing();
 610
 611   nsAccessNode::InitXPAccessibility();
 612 }
 613
 614 void nsAccessNodeWrap::ShutdownAccessibility()
 615 {
 616   NS_IF_RELEASE(gTextEvent);
 617   ::DestroyCaret();
 618
 619   if (!gIsAccessibilityActive) {
 620     return;
 621   }
 622
 623   nsAccessNode::ShutdownXPAccessibility();
 624 }
 625
 626 int nsAccessNodeWrap::FilterA11yExceptions(unsigned int aCode, EXCEPTION_POINTERS *aExceptionInfo)
 627 {
 628   if (aCode == EXCEPTION_ACCESS_VIOLATION) {
 629 #ifdef MOZ_CRASHREPORTER
 630     // MSAA swallows crashes (because it is COM-based)
 631     // but we still need to learn about those crashes so we can fix them
 632     // Make sure to pass them to the crash reporter
 633     nsCOMPtr<nsICrashReporter> crashReporter =
 634       do_GetService("@mozilla.org/toolkit/crash-reporter;1");
 635     if (crashReporter) {
 636       crashReporter->WriteMinidumpForException(aExceptionInfo);
 637     }
 638 #endif
 639   }
 640   else {
 641     NS_NOTREACHED("We should only be catching crash exceptions");
 642   }
 643   return EXCEPTION_CONTINUE_SEARCH;
 644 }
 645
 646 HRESULT
 647 GetHRESULT(nsresult aResult)
 648 {
 649   switch (aResult) {
 650     case NS_OK:
 651       return S_OK;
 652
 653     case NS_ERROR_INVALID_ARG: case NS_ERROR_INVALID_POINTER:
 654       return E_INVALIDARG;
 655
 656     case NS_ERROR_OUT_OF_MEMORY:
 657       return E_OUTOFMEMORY;
 658
 659     case NS_ERROR_NOT_IMPLEMENTED:
 660       return E_NOTIMPL;
 661
 662     default:
 663       return E_FAIL;
 664   }
 665 }
 666
 667 PRBool nsAccessNodeWrap::IsOnlyMsaaCompatibleJawsPresent()
 668 {
 669   HMODULE jhookhandle = ::GetModuleHandleW(L"jhook");
 670   if (!jhookhandle)
 671     return PR_FALSE;  // No JAWS, or some other screen reader, use IA2
 672
 673   PRUnichar fileName[MAX_PATH];
 674   ::GetModuleFileNameW(jhookhandle, fileName, MAX_PATH);
 675
 676   DWORD dummy;
 677   DWORD length = ::GetFileVersionInfoSizeW(fileName, &dummy);
 678
 679   LPBYTE versionInfo = new BYTE[length];
 680   ::GetFileVersionInfoW(fileName, 0, length, versionInfo);
 681
 682   UINT uLen;
 683   VS_FIXEDFILEINFO *fixedFileInfo;
 684   ::VerQueryValueW(versionInfo, L"\\", (LPVOID*)&fixedFileInfo, &uLen);
 685   DWORD dwFileVersionMS = fixedFileInfo->dwFileVersionMS;
 686   DWORD dwFileVersionLS = fixedFileInfo->dwFileVersionLS;
 687   delete [] versionInfo;
 688
 689   DWORD dwLeftMost = HIWORD(dwFileVersionMS);
 690 //  DWORD dwSecondLeft = LOWORD(dwFileVersionMS);
 691   DWORD dwSecondRight = HIWORD(dwFileVersionLS);
 692 //  DWORD dwRightMost = LOWORD(dwFileVersionLS);
 693
 694   return (dwLeftMost < 8
 695           || (dwLeftMost == 8 && dwSecondRight < 2173));
 696 }
 697
 698 void nsAccessNodeWrap::TurnOffNewTabSwitchingForJawsAndWE()
 699 {
 700   HMODULE srHandle = ::GetModuleHandleW(L"jhook");
 701   if (!srHandle) {
 702     // No JAWS, try Window-Eyes
 703     srHandle = ::GetModuleHandleW(L"gwm32inc");
 704     if (!srHandle) {
 705       // no screen reader we're interested in. Bail out.
 706       return;
 707     }
 708   }
 709
 710   // Check to see if the pref for disallowing CtrlTab is already set.
 711   // If so, bail out.
 712   // If not, set it.
 713   nsCOMPtr<nsIPrefBranch> prefs (do_GetService(NS_PREFSERVICE_CONTRACTID));
 714   if (prefs) {
 715     PRBool hasDisallowNewCtrlTabPref = PR_FALSE;
 716     nsresult rv = prefs->PrefHasUserValue(CTRLTAB_DISALLOW_FOR_SCREEN_READERS_PREF,
 717              &hasDisallowNewCtrlTabPref);
 718     if (NS_SUCCEEDED(rv) && hasDisallowNewCtrlTabPref) {
 719       // This pref has been set before. There is no default for it.
 720       // Do nothing further, respect the setting that's there.
 721       // That way, if noone touches it, it'll stay on after toggled once.
 722       // If someone decided to turn it off, we respect that, too.
 723       return;
 724     }
 725
 726     // Value has never been set, set it.
 727     prefs->SetBoolPref(CTRLTAB_DISALLOW_FOR_SCREEN_READERS_PREF, PR_TRUE);
 728   }
 729 }
 730
 731 void nsAccessNodeWrap::DoATSpecificProcessing()
 732 {
 733   if (IsOnlyMsaaCompatibleJawsPresent())
 734     // All versions below 8.0.2173 are not compatible
 735     gIsIA2Disabled  = PR_TRUE;
 736
 737   TurnOffNewTabSwitchingForJawsAndWE();
 738 }