C++ Accessible::ChildCount方法代码示例

nsresult
ARIAGridCellAccessible::GetAttributesInternal(nsIPersistentProperties* aAttributes)
{
  if (IsDefunct())
    return NS_ERROR_FAILURE;
  
  nsresult rv = HyperTextAccessibleWrap::GetAttributesInternal(aAttributes);
  NS_ENSURE_SUCCESS(rv, rv);

  // Expose "table-cell-index" attribute.

  Accessible* thisRow = Parent();
  if (!thisRow || thisRow->Role() != roles::ROW)
    return NS_OK;

  int32_t colIdx = 0, colCount = 0;
  uint32_t childCount = thisRow->ChildCount();
  for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
    Accessible* child = thisRow->GetChildAt(childIdx);
    if (child == this)
      colIdx = colCount;

    roles::Role role = child->Role();
    if (role == roles::GRID_CELL || role == roles::ROWHEADER ||
        role == roles::COLUMNHEADER)
      colCount++;
  }

  Accessible* table = thisRow->Parent();
  if (!table)
    return NS_OK;

  roles::Role tableRole = table->Role();
  if (tableRole != roles::TABLE && tableRole != roles::TREE_TABLE)
    return NS_OK;

  int32_t rowIdx = 0;
  childCount = table->ChildCount();
  for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
    Accessible* child = table->GetChildAt(childIdx);
    if (child == thisRow)
      break;

    if (child->Role() == roles::ROW)
      rowIdx++;
  }

  int32_t idx = rowIdx * colCount + colIdx;

  nsAutoString stringIdx;
  stringIdx.AppendInt(idx);
  nsAccUtils::SetAccAttr(aAttributes, nsGkAtoms::tableCellIndex,
                         stringIdx);

  return NS_OK;
}

void
XULListCellAccessible::ColHeaderCells(nsTArray<Accessible*>* aCells)
{
  TableAccessible* table = Table();
  NS_ASSERTION(table, "cell not in a table!");
  if (!table)
    return;

  // Get column header cell from XUL listhead.
  Accessible* list = nullptr;

  Accessible* tableAcc = table->AsAccessible();
  uint32_t tableChildCount = tableAcc->ChildCount();
  for (uint32_t childIdx = 0; childIdx < tableChildCount; childIdx++) {
    Accessible* child = tableAcc->GetChildAt(childIdx);
    if (child->Role() == roles::LIST) {
      list = child;
      break;
    }
  }

  if (list) {
    Accessible* headerCell = list->GetChildAt(ColIdx());
    if (headerCell) {
      aCells->AppendElement(headerCell);
      return;
    }
  }

  // No column header cell from XUL markup, try to get it from ARIA markup.
  TableCellAccessible::ColHeaderCells(aCells);
}

void
XULListboxAccessible::SelectedCells(nsTArray<Accessible*>* aCells)
{
  nsCOMPtr<nsIDOMXULMultiSelectControlElement> control =
    do_QueryInterface(mContent);
  NS_ASSERTION(control,
               "Doesn't implement nsIDOMXULMultiSelectControlElement.");

  nsCOMPtr<nsIDOMNodeList> selectedItems;
  control->GetSelectedItems(getter_AddRefs(selectedItems));
  if (!selectedItems)
    return;

  uint32_t selectedItemsCount = 0;
  DebugOnly<nsresult> rv = selectedItems->GetLength(&selectedItemsCount);
  NS_ASSERTION(NS_SUCCEEDED(rv), "GetLength() Shouldn't fail!");

  for (uint32_t index = 0; index < selectedItemsCount; index++) {
    nsCOMPtr<nsIDOMNode> itemNode;
    selectedItems->Item(index, getter_AddRefs(itemNode));
    nsCOMPtr<nsIContent> itemContent(do_QueryInterface(itemNode));
    Accessible* item = mDoc->GetAccessible(itemContent);

    if (item) {
      uint32_t cellCount = item->ChildCount();
      for (uint32_t cellIdx = 0; cellIdx < cellCount; cellIdx++) {
        Accessible* cell = mChildren[cellIdx];
        if (cell->Role() == roles::CELL)
          aCells->AppendElement(cell);
      }
    }
  }
}

Accessible*
AccGroupInfo::NextItemTo(Accessible* aItem)
{
  AccGroupInfo* groupInfo = aItem->GetGroupInfo();
  if (!groupInfo)
    return nullptr;

  // If the item in middle of the group then search next item in siblings.
  if (groupInfo->PosInSet() >= groupInfo->SetSize())
    return nullptr;

  Accessible* parent = aItem->Parent();
  uint32_t childCount = parent->ChildCount();
  for (uint32_t idx = aItem->IndexInParent() + 1; idx < childCount; idx++) {
    Accessible* nextItem = parent->GetChildAt(idx);
    AccGroupInfo* nextGroupInfo = nextItem->GetGroupInfo();
    if (nextGroupInfo &&
        nextGroupInfo->ConceptualParent() == groupInfo->ConceptualParent()) {
      return nextItem;
    }
  }

  NS_NOTREACHED("Item in the middle of the group but there's no next item!");
  return nullptr;
}

void
XULToolbarButtonAccessible::GetPositionAndSizeInternal(int32_t* aPosInSet,
                                                       int32_t* aSetSize)
{
  int32_t setSize = 0;
  int32_t posInSet = 0;

  Accessible* parent = Parent();
  if (!parent)
    return;

  uint32_t childCount = parent->ChildCount();
  for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
    Accessible* child = parent->GetChildAt(childIdx);
    if (IsSeparator(child)) { // end of a group of buttons
      if (posInSet)
        break; // we've found our group, so we're done

      setSize = 0; // not our group, so start a new group

    } else {
      setSize++; // another button in the group

      if (child == this)
        posInSet = setSize; // we've found our button
    }
  }

  *aPosInSet = posInSet;
  *aSetSize = setSize;
}

nsIContent*
nsXFormsSelectableAccessible::GetItemByIndex(PRUint32* aIndex,
                                             Accessible* aAccessible)
{
  Accessible* accessible = aAccessible ? aAccessible : this;
  PRUint32 childCount = accessible->ChildCount();
  for (PRUint32 childIdx = 0; childIdx < childCount; childIdx++) {
    Accessible* child = accessible->GetChildAt(childIdx);
    nsIContent* childContent = child->GetContent();
    nsINodeInfo *nodeInfo = childContent->NodeInfo();
    if (nodeInfo->NamespaceEquals(NS_LITERAL_STRING(NS_NAMESPACE_XFORMS))) {
      if (nodeInfo->Equals(nsGkAtoms::item)) {
        if (!*aIndex)
          return childContent;

        --*aIndex;
      } else if (nodeInfo->Equals(nsGkAtoms::choices)) {
        nsIContent* itemContent = GetItemByIndex(aIndex, child);
        if (itemContent)
          return itemContent;
      }
    }
  }

  return nsnull;
}

void
TextRange::EmbeddedChildren(nsTArray<Accessible*>* aChildren) const
{
  if (mStartContainer == mEndContainer) {
    int32_t startIdx = mStartContainer->GetChildIndexAtOffset(mStartOffset);
    int32_t endIdx = mStartContainer->GetChildIndexAtOffset(mEndOffset);
    for (int32_t idx = startIdx; idx <= endIdx; idx++) {
      Accessible* child = mStartContainer->GetChildAt(idx);
      if (nsAccUtils::IsEmbeddedObject(child))
        aChildren->AppendElement(child);
    }
    return;
  }

  Accessible* p1 = mStartContainer->GetChildAtOffset(mStartOffset);
  Accessible* p2 = mEndContainer->GetChildAtOffset(mEndOffset);

  uint32_t pos1 = 0, pos2 = 0;
  AutoTArray<Accessible*, 30> parents1, parents2;
  Accessible* container =
    CommonParent(p1, p2, &parents1, &pos1, &parents2, &pos2);

  // Traverse the tree up to the container and collect embedded objects.
  for (uint32_t idx = 0; idx < pos1 - 1; idx++) {
    Accessible* parent = parents1[idx + 1];
    Accessible* child = parents1[idx];
    uint32_t childCount = parent->ChildCount();
    for (uint32_t childIdx = child->IndexInParent(); childIdx < childCount; childIdx++) {
      Accessible* next = parent->GetChildAt(childIdx);
      if (nsAccUtils::IsEmbeddedObject(next))
        aChildren->AppendElement(next);
    }
  }

  // Traverse through direct children in the container.
  int32_t endIdx = parents2[pos2 - 1]->IndexInParent();
  int32_t childIdx = parents1[pos1 - 1]->IndexInParent() + 1;
  for (; childIdx < endIdx; childIdx++) {
    Accessible* next = container->GetChildAt(childIdx);
    if (nsAccUtils::IsEmbeddedObject(next))
      aChildren->AppendElement(next);
  }

  // Traverse down from the container to end point.
  for (int32_t idx = pos2 - 2; idx > 0; idx--) {
    Accessible* parent = parents2[idx];
    Accessible* child = parents2[idx - 1];
    int32_t endIdx = child->IndexInParent();
    for (int32_t childIdx = 0; childIdx < endIdx; childIdx++) {
      Accessible* next = parent->GetChildAt(childIdx);
      if (nsAccUtils::IsEmbeddedObject(next))
        aChildren->AppendElement(next);
    }
  }
}

NS_IMETHODIMP
nsXULListboxAccessible::GetSelectedCells(nsIArray **aCells)
{
  NS_ENSURE_ARG_POINTER(aCells);
  *aCells = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsresult rv = NS_OK;
  nsCOMPtr<nsIMutableArray> selCells =
    do_CreateInstance(NS_ARRAY_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIDOMXULMultiSelectControlElement> control =
    do_QueryInterface(mContent);
  NS_ASSERTION(control,
               "Doesn't implement nsIDOMXULMultiSelectControlElement.");

  nsCOMPtr<nsIDOMNodeList> selectedItems;
  control->GetSelectedItems(getter_AddRefs(selectedItems));
  if (!selectedItems)
    return NS_OK;

  PRUint32 selectedItemsCount = 0;
  rv = selectedItems->GetLength(&selectedItemsCount);
  NS_ENSURE_SUCCESS(rv, rv);

  NS_ENSURE_TRUE(mDoc, NS_ERROR_FAILURE);
  PRUint32 index = 0;
  for (; index < selectedItemsCount; index++) {
    nsCOMPtr<nsIDOMNode> itemNode;
    selectedItems->Item(index, getter_AddRefs(itemNode));
    nsCOMPtr<nsIContent> itemContent(do_QueryInterface(itemNode));
    Accessible* item = mDoc->GetAccessible(itemContent);

    if (item) {
      PRUint32 cellCount = item->ChildCount();
      for (PRUint32 cellIdx = 0; cellIdx < cellCount; cellIdx++) {
        Accessible* cell = mChildren[cellIdx];
        if (cell->Role() == roles::CELL)
          selCells->AppendElement(static_cast<nsIAccessible*>(cell), false);
      }
    }
  }

  NS_ADDREF(*aCells = selCells);
  return NS_OK;
}

already_AddRefed<nsIPersistentProperties>
ARIAGridCellAccessible::NativeAttributes()
{
    nsCOMPtr<nsIPersistentProperties> attributes =
        HyperTextAccessibleWrap::NativeAttributes();

    // Expose "table-cell-index" attribute.
    Accessible* thisRow = Row();
    if (!thisRow)
        return attributes.forget();

    int32_t colIdx = 0, colCount = 0;
    uint32_t childCount = thisRow->ChildCount();
    for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
        Accessible* child = thisRow->GetChildAt(childIdx);
        if (child == this)
            colIdx = colCount;

        roles::Role role = child->Role();
        if (role == roles::CELL || role == roles::GRID_CELL ||
                role == roles::ROWHEADER || role == roles::COLUMNHEADER)
            colCount++;
    }

    int32_t rowIdx = RowIndexFor(thisRow);

    nsAutoString stringIdx;
    stringIdx.AppendInt(rowIdx * colCount + colIdx);
    nsAccUtils::SetAccAttr(attributes, nsGkAtoms::tableCellIndex, stringIdx);

#ifdef DEBUG
    nsAutoString unused;
    attributes->SetStringProperty(NS_LITERAL_CSTRING("cppclass"),
                                  NS_LITERAL_STRING("ARIAGridCellAccessible"),
                                  unused);
#endif

    return attributes.forget();
}

bool
HTMLTableAccessible::IsProbablyLayoutTable()
{
  // Implement a heuristic to determine if table is most likely used for layout
  // XXX do we want to look for rowspan or colspan, especialy that span all but a couple cells
  // at the beginning or end of a row/col, and especially when they occur at the edge of a table?
  // XXX expose this info via object attributes to AT-SPI

  // XXX For now debugging descriptions are always on via SHOW_LAYOUT_HEURISTIC
  // This will allow release trunk builds to be used by testers to refine the algorithm
  // Change to |#define SHOW_LAYOUT_HEURISTIC DEBUG| before final release
#ifdef SHOW_LAYOUT_HEURISTIC
#define RETURN_LAYOUT_ANSWER(isLayout, heuristic) \
  { \
    mLayoutHeuristic = isLayout ? \
      NS_LITERAL_STRING("layout table: " heuristic) : \
      NS_LITERAL_STRING("data table: " heuristic); \
    return isLayout; \
  }
#else
#define RETURN_LAYOUT_ANSWER(isLayout, heuristic) { return isLayout; }
#endif

  DocAccessible* docAccessible = Document();
  if (docAccessible) {
    uint64_t docState = docAccessible->State();
    if (docState & states::EDITABLE) {  // Need to see all elements while document is being edited
      RETURN_LAYOUT_ANSWER(false, "In editable document");
    }
  }

  // Check to see if an ARIA role overrides the role from native markup,
  // but for which we still expose table semantics (treegrid, for example).
  if (Role() != roles::TABLE)
    RETURN_LAYOUT_ANSWER(false, "Has role attribute");

  if (mContent->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::role)) {
    // Role attribute is present, but overridden roles have already been dealt with.
    // Only landmarks and other roles that don't override the role from native
    // markup are left to deal with here.
    RETURN_LAYOUT_ANSWER(false, "Has role attribute, weak role, and role is table");
  }

  NS_ASSERTION(mContent->IsHTMLElement(nsGkAtoms::table),
    "table should not be built by CSS display:table style");

  // Check if datatable attribute has "0" value.
  if (mContent->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::datatable,
                            NS_LITERAL_STRING("0"), eCaseMatters)) {
    RETURN_LAYOUT_ANSWER(true, "Has datatable = 0 attribute, it's for layout");
  }

  // Check for legitimate data table attributes.
  nsAutoString summary;
  if (mContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::summary, summary) &&
      !summary.IsEmpty())
    RETURN_LAYOUT_ANSWER(false, "Has summary -- legitimate table structures");

  // Check for legitimate data table elements.
  Accessible* caption = FirstChild();
  if (caption && caption->Role() == roles::CAPTION && caption->HasChildren())
    RETURN_LAYOUT_ANSWER(false, "Not empty caption -- legitimate table structures");

  for (nsIContent* childElm = mContent->GetFirstChild(); childElm;
       childElm = childElm->GetNextSibling()) {
    if (!childElm->IsHTMLElement())
      continue;

    if (childElm->IsAnyOfHTMLElements(nsGkAtoms::col,
                                      nsGkAtoms::colgroup,
                                      nsGkAtoms::tfoot,
                                      nsGkAtoms::thead)) {
      RETURN_LAYOUT_ANSWER(false,
                           "Has col, colgroup, tfoot or thead -- legitimate table structures");
    }

    if (childElm->IsHTMLElement(nsGkAtoms::tbody)) {
      for (nsIContent* rowElm = childElm->GetFirstChild(); rowElm;
           rowElm = rowElm->GetNextSibling()) {
        if (rowElm->IsHTMLElement(nsGkAtoms::tr)) {
          for (nsIContent* cellElm = rowElm->GetFirstChild(); cellElm;
               cellElm = cellElm->GetNextSibling()) {
            if (cellElm->IsHTMLElement()) {

              if (cellElm->NodeInfo()->Equals(nsGkAtoms::th)) {
                RETURN_LAYOUT_ANSWER(false,
                                     "Has th -- legitimate table structures");
              }

              if (cellElm->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::headers) ||
                  cellElm->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::scope) ||
                  cellElm->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::abbr)) {
                RETURN_LAYOUT_ANSWER(false,
                                     "Has headers, scope, or abbr attribute -- legitimate table structures");
              }

              Accessible* cell = mDoc->GetAccessible(cellElm);
              if (cell && cell->ChildCount() == 1 &&
                  cell->FirstChild()->IsAbbreviation()) {
                RETURN_LAYOUT_ANSWER(false,
//.........这里部分代码省略.........

void
RootAccessible::HandlePopupHidingEvent(nsINode* aPopupNode)
{
  // Get popup accessible. There are cases when popup element isn't accessible
  // but an underlying widget is and behaves like popup, an example is
  // autocomplete popups.
  DocAccessible* document = nsAccUtils::GetDocAccessibleFor(aPopupNode);
  if (!document)
    return;

  Accessible* popup = document->GetAccessible(aPopupNode);
  if (!popup) {
    Accessible* popupContainer = document->GetContainerAccessible(aPopupNode);
    if (!popupContainer)
      return;

    uint32_t childCount = popupContainer->ChildCount();
    for (uint32_t idx = 0; idx < childCount; idx++) {
      Accessible* child = popupContainer->GetChildAt(idx);
      if (child->IsAutoCompletePopup()) {
        popup = child;
        break;
      }
    }

    // No popup no events. Focus is managed by DOM. This is a case for
    // menupopups of menus on Linux since there are no accessible for popups.
    if (!popup)
      return;
  }

  // In case of autocompletes and comboboxes fire state change event for
  // expanded state. Note, HTML form autocomplete isn't a subject of state
  // change event because they aren't autocompletes strictly speaking.
  // When popup closes (except nested popups and menus) then fire focus event to
  // where it was. The focus event is expected even if popup didn't take a focus.

  static const uint32_t kNotifyOfFocus = 1;
  static const uint32_t kNotifyOfState = 2;
  uint32_t notifyOf = 0;

  // HTML select is target of popuphidding event. Otherwise get container
  // widget. No container widget means this is either tooltip or menupopup.
  // No events in the former case.
  Accessible* widget = nullptr;
  if (popup->IsCombobox()) {
    widget = popup;
  } else {
    widget = popup->ContainerWidget();
    if (!widget) {
      if (!popup->IsMenuPopup())
        return;

      widget = popup;
    }
  }

  if (popup->IsAutoCompletePopup()) {
    // No focus event for autocomplete because it's managed by
    // DOMMenuItemInactive events.
    if (widget->IsAutoComplete())
      notifyOf = kNotifyOfState;

  } else if (widget->IsCombobox()) {
    // Fire focus for active combobox, otherwise the focus is managed by DOM
    // focus notifications. Always fire state change event.
    if (widget->IsActiveWidget())
      notifyOf = kNotifyOfFocus;
    notifyOf |= kNotifyOfState;

  } else if (widget->IsMenuButton()) {
    // Can be a part of autocomplete.
    Accessible* compositeWidget = widget->ContainerWidget();
    if (compositeWidget && compositeWidget->IsAutoComplete()) {
      widget = compositeWidget;
      notifyOf = kNotifyOfState;
    }

    // Autocomplete (like searchbar) can be inactive when popup hiddens
    notifyOf |= kNotifyOfFocus;

  } else if (widget == popup) {
    // Top level context menus and alerts.
    // Ignore submenus and menubar. When submenu is closed then sumbenu
    // container menuitem takes a focus via DOMMenuItemActive notification.
    // For menubars processing we listen DOMMenubarActive/Inactive
    // notifications.
    notifyOf = kNotifyOfFocus;
  }

  // Restore focus to where it was.
  if (notifyOf & kNotifyOfFocus) {
    FocusMgr()->ActiveItemChanged(nullptr);
#ifdef A11Y_LOG
    if (logging::IsEnabled(logging::eFocus))
      logging::ActiveItemChangeCausedBy("popuphiding", popup);
#endif
  }

  // Fire expanded state change event.
//.........这里部分代码省略.........

bool
TableAccessible::IsProbablyLayoutTable()
{
  // Implement a heuristic to determine if table is most likely used for layout.

  // XXX do we want to look for rowspan or colspan, especialy that span all but
  // a couple cells  at the beginning or end of a row/col, and especially when
  // they occur at the edge of a table?

  // XXX For now debugging descriptions are always on via SHOW_LAYOUT_HEURISTIC
  // This will allow release trunk builds to be used by testers to refine
  // the algorithm. Integrate it into Logging.
  // Change to |#define SHOW_LAYOUT_HEURISTIC DEBUG| before final release
#ifdef SHOW_LAYOUT_HEURISTIC
#define RETURN_LAYOUT_ANSWER(isLayout, heuristic) \
  { \
    mLayoutHeuristic = isLayout ? \
      NS_LITERAL_STRING("layout table: " heuristic) : \
      NS_LITERAL_STRING("data table: " heuristic); \
    return isLayout; \
  }
#else
#define RETURN_LAYOUT_ANSWER(isLayout, heuristic) { return isLayout; }
#endif

  Accessible* thisacc = AsAccessible();

  // Need to see all elements while document is being edited.
  if (thisacc->Document()->State() & states::EDITABLE) {
    RETURN_LAYOUT_ANSWER(false, "In editable document");
  }

  // Check to see if an ARIA role overrides the role from native markup,
  // but for which we still expose table semantics (treegrid, for example).
  if (thisacc->HasARIARole()) {
    RETURN_LAYOUT_ANSWER(false, "Has role attribute");
  }

  dom::Element* el = thisacc->Elm();
  if (el->IsMathMLElement(nsGkAtoms::mtable_)) {
    RETURN_LAYOUT_ANSWER(false, "MathML matrix");
  }

  MOZ_ASSERT(el->IsHTMLElement(nsGkAtoms::table),
             "Table should not be built by CSS display:table style");

  // Check if datatable attribute has "0" value.
  if (el->AttrValueIs(kNameSpaceID_None, nsGkAtoms::datatable,
                      NS_LITERAL_STRING("0"), eCaseMatters)) {
    RETURN_LAYOUT_ANSWER(true, "Has datatable = 0 attribute, it's for layout");
  }

  // Check for legitimate data table attributes.
  nsAutoString summary;
  if (el->GetAttr(kNameSpaceID_None, nsGkAtoms::summary, summary) &&
      !summary.IsEmpty()) {
    RETURN_LAYOUT_ANSWER(false, "Has summary -- legitimate table structures");
  }

  // Check for legitimate data table elements.
  Accessible* caption = thisacc->FirstChild();
  if (caption && caption->IsHTMLCaption() && caption->HasChildren()) {
    RETURN_LAYOUT_ANSWER(false, "Not empty caption -- legitimate table structures");
  }

  for (nsIContent* childElm = el->GetFirstChild(); childElm;
       childElm = childElm->GetNextSibling()) {
    if (!childElm->IsHTMLElement())
      continue;

    if (childElm->IsAnyOfHTMLElements(nsGkAtoms::col,
                                      nsGkAtoms::colgroup,
                                      nsGkAtoms::tfoot,
                                      nsGkAtoms::thead)) {
      RETURN_LAYOUT_ANSWER(false,
                           "Has col, colgroup, tfoot or thead -- legitimate table structures");
    }

    if (childElm->IsHTMLElement(nsGkAtoms::tbody)) {
      for (nsIContent* rowElm = childElm->GetFirstChild(); rowElm;
           rowElm = rowElm->GetNextSibling()) {
        if (rowElm->IsHTMLElement(nsGkAtoms::tr)) {
          for (nsIContent* cellElm = rowElm->GetFirstChild(); cellElm;
               cellElm = cellElm->GetNextSibling()) {
            if (cellElm->IsHTMLElement()) {

              if (cellElm->NodeInfo()->Equals(nsGkAtoms::th)) {
                RETURN_LAYOUT_ANSWER(false,
                                     "Has th -- legitimate table structures");
              }

              if (cellElm->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::headers) ||
                  cellElm->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::scope) ||
                  cellElm->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::abbr)) {
                RETURN_LAYOUT_ANSWER(false,
                                     "Has headers, scope, or abbr attribute -- legitimate table structures");
              }

              Accessible* cell = thisacc->Document()->GetAccessible(cellElm);
              if (cell && cell->ChildCount() == 1 &&
//.........这里部分代码省略.........