C++ Accessible::GetChildAt方法代码示例

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);
}

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
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);
    }
  }
}

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;
}

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;
}

Accessible*
nsAccessiblePivot::SearchBackward(Accessible* aAccessible,
                                  nsIAccessibleTraversalRule* aRule,
                                  bool aSearchCurrent,
                                  nsresult* aResult)
{
  *aResult = NS_OK;

  // Initial position could be unset, in that case return null.
  if (!aAccessible)
    return nullptr;

  RuleCache cache(aRule);
  uint16_t filtered = nsIAccessibleTraversalRule::FILTER_IGNORE;
  Accessible* accessible = AdjustStartPosition(aAccessible, cache,
                                               &filtered, aResult);
  NS_ENSURE_SUCCESS(*aResult, nullptr);

  if (aSearchCurrent && (filtered & nsIAccessibleTraversalRule::FILTER_MATCH)) {
    return accessible;
  }

  Accessible* root = GetActiveRoot();
  while (accessible != root) {
    Accessible* parent = accessible->Parent();
    int32_t idxInParent = accessible->IndexInParent();
    while (idxInParent > 0) {
      if (!(accessible = parent->GetChildAt(--idxInParent)))
        continue;

      *aResult = cache.ApplyFilter(accessible, &filtered);
      NS_ENSURE_SUCCESS(*aResult, nullptr);

      Accessible* lastChild = nullptr;
      while (!(filtered & nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE) &&
             (lastChild = accessible->LastChild())) {
        parent = accessible;
        accessible = lastChild;
        idxInParent = accessible->IndexInParent();
        *aResult = cache.ApplyFilter(accessible, &filtered);
        NS_ENSURE_SUCCESS(*aResult, nullptr);
      }

      if (filtered & nsIAccessibleTraversalRule::FILTER_MATCH)
        return accessible;
    }

    if (!(accessible = parent))
      break;

    *aResult = cache.ApplyFilter(accessible, &filtered);
    NS_ENSURE_SUCCESS(*aResult, nullptr);

    if (filtered & nsIAccessibleTraversalRule::FILTER_MATCH)
      return accessible;
  }

  return nullptr;
}

void XULTreeGridAccessible::ColDescription(uint32_t aColIdx,
                                           nsString& aDescription) {
  aDescription.Truncate();

  Accessible* treeColumns = Accessible::GetChildAt(0);
  if (treeColumns) {
    Accessible* treeColumnItem = treeColumns->GetChildAt(aColIdx);
    if (treeColumnItem) treeColumnItem->Name(aDescription);
  }
}

uint32_t ARIAGridCellAccessible::ColIdx() const {
  Accessible* row = Row();
  if (!row) return 0;

  int32_t indexInRow = IndexInParent();
  uint32_t colIdx = 0;
  for (int32_t idx = 0; idx < indexInRow; idx++) {
    Accessible* cell = row->GetChildAt(idx);
    if (cell->IsTableCell()) {
      colIdx += cell->AsTableCell()->ColExtent();
    }
  }

  return colIdx;
}

NS_IMETHODIMP
nsXULListCellAccessible::GetColumnHeaderCells(nsIArray **aHeaderCells)
{
  NS_ENSURE_ARG_POINTER(aHeaderCells);
  *aHeaderCells = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessibleTable> table;
  GetTable(getter_AddRefs(table));
  NS_ENSURE_STATE(table); // we expect to be in a listbox (table)

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

  nsRefPtr<Accessible> tableAcc(do_QueryObject(table));
  PRUint32 tableChildCount = tableAcc->ChildCount();
  for (PRUint32 childIdx = 0; childIdx < tableChildCount; childIdx++) {
    Accessible* child = tableAcc->GetChildAt(childIdx);
    if (child->Role() == roles::LIST) {
      list = child;
      break;
    }
  }

  if (list) {
    PRInt32 colIdx = -1;
    GetColumnIndex(&colIdx);

    nsIAccessible *headerCell = list->GetChildAt(colIdx);
    if (headerCell) {
      nsresult rv = NS_OK;
      nsCOMPtr<nsIMutableArray> headerCells =
        do_CreateInstance(NS_ARRAY_CONTRACTID, &rv);
      NS_ENSURE_SUCCESS(rv, rv);

      headerCells->AppendElement(headerCell, false);
      NS_ADDREF(*aHeaderCells = headerCells);
      return NS_OK;
    }
  }

  // No column header cell from XUL markup, try to get it from ARIA markup.
  return nsAccUtils::GetHeaderCellsFor(table, this,
                                       nsAccUtils::eColumnHeaderCells,
                                       aHeaderCells);
}

uint32_t
XULListCellAccessible::ColIdx() const
{
  Accessible* row = Parent();
  if (!row)
    return 0;

  int32_t indexInRow = IndexInParent();
  uint32_t colIdx = 0;
  for (int32_t idx = 0; idx < indexInRow; idx++) {
    Accessible* cell = row->GetChildAt(idx);
    roles::Role role = cell->Role();
    if (role == roles::CELL || role == roles::GRID_CELL ||
        role == roles::ROWHEADER || role == roles::COLUMNHEADER)
      colIdx++;
  }

  return colIdx;
}

Accessible*
XULListboxAccessible::CellAt(uint32_t aRowIndex, uint32_t aColumnIndex)
{
  nsCOMPtr<nsIDOMXULSelectControlElement> control =
    do_QueryInterface(mContent);
  NS_ENSURE_TRUE(control, nullptr);

  nsCOMPtr<nsIDOMXULSelectControlItemElement> item;
  control->GetItemAtIndex(aRowIndex, getter_AddRefs(item));
  if (!item)
    return nullptr;

  nsCOMPtr<nsIContent> itemContent(do_QueryInterface(item));
  if (!itemContent)
    return nullptr;

  Accessible* row = mDoc->GetAccessible(itemContent);
  NS_ENSURE_TRUE(row, nullptr);

  return row->GetChildAt(aColumnIndex);
}

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();
}

//.........这里部分代码省略.........
  if (rowCount <=1) {
    RETURN_LAYOUT_ANSWER(true, "Has only 1 row");
  }

  // Check for many columns.
  if (colCount >= 5) {
    RETURN_LAYOUT_ANSWER(false, ">=5 columns");
  }

  // Now we know there are 2-4 columns and 2 or more rows. Check to see if
  // there are visible borders on the cells.
  // XXX currently, we just check the first cell -- do we really need to do more?
  nsTableWrapperFrame* tableFrame = do_QueryFrame(el->GetPrimaryFrame());
  if (!tableFrame) {
    RETURN_LAYOUT_ANSWER(false, "table with no frame!");
  }

  nsIFrame* cellFrame = tableFrame->GetCellFrameAt(0, 0);
  if (!cellFrame) {
    RETURN_LAYOUT_ANSWER(false, "table's first cell has no frame!");
  }

  nsMargin border;
  cellFrame->GetXULBorder(border);
  if (border.top && border.bottom && border.left && border.right) {
    RETURN_LAYOUT_ANSWER(false, "Has nonzero border-width on table cell");
  }

  // Rules for non-bordered tables with 2-4 columns and 2+ rows from here on
  // forward.

  // Check for styled background color across rows (alternating background
  // color is a common feature for data tables).
  auto childCount = thisacc->ChildCount();
  nscolor rowColor = 0;
  nscolor prevRowColor;
  for (auto childIdx = 0U; childIdx < childCount; childIdx++) {
    Accessible* child = thisacc->GetChildAt(childIdx);
    if (child->IsHTMLTableRow()) {
      prevRowColor = rowColor;
      nsIFrame* rowFrame = child->GetFrame();
      MOZ_ASSERT(rowFrame, "Table hierarchy got screwed up");
      if (!rowFrame) {
        RETURN_LAYOUT_ANSWER(false, "Unexpected table hierarchy");
      }

      rowColor = rowFrame->StyleBackground()->BackgroundColor(rowFrame);

      if (childIdx > 0 && prevRowColor != rowColor) {
        RETURN_LAYOUT_ANSWER(
          false, "2 styles of row background color, non-bordered"
        );
      }
    }
  }

  // Check for many rows.
  const uint32_t kMaxLayoutRows = 20;
  if (rowCount > kMaxLayoutRows) { // A ton of rows, this is probably for data
    RETURN_LAYOUT_ANSWER(false, ">= kMaxLayoutRows (20) and non-bordered");
  }

  // Check for very wide table.
  nsIFrame* documentFrame = thisacc->Document()->GetFrame();
  nsSize documentSize = documentFrame->GetSize();
  if (documentSize.width > 0) {
    nsSize tableSize = thisacc->GetFrame()->GetSize();
    int32_t percentageOfDocWidth = (100 * tableSize.width) / documentSize.width;
    if (percentageOfDocWidth > 95) {
      // 3-4 columns, no borders, not a lot of rows, and 95% of the doc's width
      // Probably for layout
      RETURN_LAYOUT_ANSWER(
        true, "<= 4 columns, table width is 95% of document width"
      );
    }
  }

  // Two column rules.
  if (rowCount * colCount <= 10) {
    RETURN_LAYOUT_ANSWER(true, "2-4 columns, 10 cells or less, non-bordered");
  }

  static const nsLiteralString tags[] = {
    NS_LITERAL_STRING("embed"),
    NS_LITERAL_STRING("object"),
    NS_LITERAL_STRING("iframe")
  };
  for (auto& tag : tags) {
    nsCOMPtr<nsIHTMLCollection> descendants = el->GetElementsByTagName(tag);
    if (descendants->Length() > 0) {
      RETURN_LAYOUT_ANSWER(
        true, "Has no borders, and has iframe, object or embed, typical of advertisements"
      );
    }
  }

  RETURN_LAYOUT_ANSWER(
    false, "No layout factor strong enough, so will guess data"
  );
}

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.........