gecko/accessible/src/base/nsARIAGridAccessible.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Mozilla Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsARIAGridAccessible.h"


////////////////////////////////////////////////////////////////////////////////
// nsARIAGridAccessible
////////////////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////////////////
// Constructor

nsARIAGridAccessible::nsARIAGridAccessible(nsIDOMNode* aDomNode,
                                           nsIWeakReference* aShell) :
  nsAccessibleWrap(aDomNode, aShell)
{
}

////////////////////////////////////////////////////////////////////////////////
// nsISupports

NS_IMPL_ISUPPORTS_INHERITED1(nsARIAGridAccessible,
                             nsAccessible,
                             nsIAccessibleTable)

////////////////////////////////////////////////////////////////////////////////
// nsIAccessibleTable

NS_IMETHODIMP
nsARIAGridAccessible::GetCaption(nsIAccessible **aCaption)
{
  NS_ENSURE_ARG_POINTER(aCaption);
  *aCaption = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  // XXX: should be pointed by aria-labelledby on grid?
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSummary(nsAString &aSummary)
{
  aSummary.Truncate();

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  // XXX: should be pointed by aria-describedby on grid?
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetColumns(PRInt32 *aColumns)
{
  NS_ENSURE_ARG_POINTER(aColumns);
  *aColumns = 0;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row = GetNextRow();
  nsCOMPtr<nsIAccessible> cell;
  while ((cell = GetNextCellInRow(row, cell)))
    (*aColumns)++;

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetColumnHeader(nsIAccessibleTable **aColumnHeader)
{
  NS_ENSURE_ARG_POINTER(aColumnHeader);
  *aColumnHeader = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  // XXX: what should we return here?
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetRows(PRInt32 *aRows)
{
  NS_ENSURE_ARG_POINTER(aRows);
  *aRows = 0;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row;
  while ((row = GetNextRow(row)))
    (*aRows)++;

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetRowHeader(nsIAccessibleTable **aRowHeader)
{
  NS_ENSURE_ARG_POINTER(aRowHeader);
  *aRowHeader = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  // XXX: what should we return here?
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsARIAGridAccessible::CellRefAt(PRInt32 aRow, PRInt32 aColumn,
                                nsIAccessible **aAccessible)
{
  NS_ENSURE_ARG_POINTER(aAccessible);
  *aAccessible = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row = GetRowAt(aRow);
  NS_ENSURE_ARG(row);

  nsCOMPtr<nsIAccessible> cell = GetCellInRowAt(row, aColumn);
  NS_ENSURE_ARG(cell);

  NS_ADDREF(*aAccessible = cell);
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetIndexAt(PRInt32 aRow, PRInt32 aColumn, PRInt32 *aIndex)
{
  NS_ENSURE_ARG_POINTER(aIndex);
  *aIndex = -1;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(aRow >= 0 && aColumn >= 0);

  PRInt32 rowCount = 0;
  GetRows(&rowCount);
  NS_ENSURE_ARG(aRow < rowCount);

  PRInt32 colCount = 0;
  GetColumns(&colCount);
  NS_ENSURE_ARG(aColumn < colCount);

  *aIndex = colCount * aRow + aColumn;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetColumnAtIndex(PRInt32 aIndex, PRInt32 *aColumn)
{
  NS_ENSURE_ARG_POINTER(aColumn);
  *aColumn = -1;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(aIndex >= 0);

  PRInt32 rowCount = 0;
  GetRows(&rowCount);
  
  PRInt32 colCount = 0;
  GetColumns(&colCount);

  NS_ENSURE_ARG(aIndex < rowCount * colCount);

  *aColumn = aIndex % colCount;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetRowAtIndex(PRInt32 aIndex, PRInt32 *aRow)
{
  NS_ENSURE_ARG_POINTER(aRow);
  *aRow = -1;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(aIndex >= 0);

  PRInt32 rowCount = 0;
  GetRows(&rowCount);

  PRInt32 colCount = 0;
  GetColumns(&colCount);

  NS_ENSURE_ARG(aIndex < rowCount * colCount);

  *aRow = aIndex / colCount;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetColumnExtentAt(PRInt32 aRow, PRInt32 aColumn,
                                        PRInt32 *aExtentCount)
{
  NS_ENSURE_ARG_POINTER(aExtentCount);
  *aExtentCount = 0;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(IsValidRowNColumn(aRow, aColumn));

  *aExtentCount = 1;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetRowExtentAt(PRInt32 aRow, PRInt32 aColumn,
                                      PRInt32 *aExtentCount)
{
  NS_ENSURE_ARG_POINTER(aExtentCount);
  *aExtentCount = 0;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(IsValidRowNColumn(aRow, aColumn));

  *aExtentCount = 1;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetColumnDescription(PRInt32 aColumn,
                                           nsAString& aDescription)
{
  aDescription.Truncate();

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(IsValidColumn(aColumn));

  // XXX: not implemented
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetRowDescription(PRInt32 aRow, nsAString& aDescription)
{
  aDescription.Truncate();

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(IsValidRow(aRow));

  // XXX: not implemented
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsARIAGridAccessible::IsColumnSelected(PRInt32 aColumn, PRBool *aIsSelected)
{
  NS_ENSURE_ARG_POINTER(aIsSelected);
  *aIsSelected = PR_FALSE;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  NS_ENSURE_ARG(IsValidColumn(aColumn));

  nsCOMPtr<nsIAccessible> row = GetNextRow();
  if (!row)
    return NS_OK;

  do {
    if (!IsARIASelected(row)) {
      nsCOMPtr<nsIAccessible> cell = GetCellInRowAt(row, aColumn);
      if (!cell) // Do not fail due to wrong markup
        return NS_OK;
      
      if (!IsARIASelected(cell))
        return NS_OK;
    }
  } while ((row = GetNextRow(row)));

  *aIsSelected = PR_TRUE;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::IsRowSelected(PRInt32 aRow, PRBool *aIsSelected)
{
  NS_ENSURE_ARG_POINTER(aIsSelected);
  *aIsSelected = PR_FALSE;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row = GetRowAt(aRow);
  NS_ENSURE_ARG(row);

  if (!IsARIASelected(row)) {
    nsCOMPtr<nsIAccessible> cell;
    while ((cell = GetNextCellInRow(row, cell))) {
      if (!IsARIASelected(cell))
        return NS_OK;
    }
  }

  *aIsSelected = PR_TRUE;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::IsCellSelected(PRInt32 aRow, PRInt32 aColumn,
                                     PRBool *aIsSelected)
{
  NS_ENSURE_ARG_POINTER(aIsSelected);
  *aIsSelected = PR_FALSE;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row(GetRowAt(aRow));
  NS_ENSURE_ARG(row);

  if (!IsARIASelected(row)) {
    nsCOMPtr<nsIAccessible> cell(GetCellInRowAt(row, aColumn));
    NS_ENSURE_ARG(cell);

    if (!IsARIASelected(cell))
      return NS_OK;
  }

  *aIsSelected = PR_TRUE;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSelectedCellsCount(PRUint32* aCount)
{
  NS_ENSURE_ARG_POINTER(aCount);
  *aCount = 0;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  PRInt32 colCount = 0;
  GetColumns(&colCount);
  
  nsCOMPtr<nsIAccessible> row;
  while ((row = GetNextRow(row))) {
    if (IsARIASelected(row)) {
      (*aCount) += colCount;
      continue;
    }

    nsCOMPtr<nsIAccessible> cell;
    while ((cell = GetNextCellInRow(row, cell))) {
      if (IsARIASelected(cell))
        (*aCount)++;
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSelectedColumnsCount(PRUint32* aCount)
{
  return GetSelectedColumnsArray(aCount);
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSelectedRowsCount(PRUint32* aCount)
{
  NS_ENSURE_ARG_POINTER(aCount);
  *aCount = 0;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row;
  while ((row = GetNextRow(row))) {
    if (IsARIASelected(row)) {
      (*aCount)++;
      continue;
    }

    nsCOMPtr<nsIAccessible> cell = GetNextCellInRow(row);
    if (!cell)
      continue;

    PRBool isRowSelected = PR_TRUE;
    do {
      if (!IsARIASelected(cell)) {
        isRowSelected = PR_FALSE;
        break;
      }
    } while ((cell = GetNextCellInRow(row, cell)));

    if (isRowSelected)
      (*aCount)++;
  }

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSelectedCells(PRUint32 *aCellsCount, PRInt32 **aCells)
{
  NS_ENSURE_ARG_POINTER(aCellsCount);
  *aCellsCount = 0;
  NS_ENSURE_ARG_POINTER(aCells);
  *aCells = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  PRInt32 rowCount = 0;
  GetRows(&rowCount);

  PRInt32 colCount = 0;
  GetColumns(&colCount);

  nsTArray<PRInt32> selCells(rowCount * colCount);

  nsCOMPtr<nsIAccessible> row;
  for (PRInt32 rowIdx = 0; row = GetNextRow(row); rowIdx++) {
    if (IsARIASelected(row)) {
      for (PRInt32 colIdx = 0; colIdx < colCount; colIdx++)
        selCells.AppendElement(rowIdx * colCount + colIdx);

      continue;
    }

    nsCOMPtr<nsIAccessible> cell;
    for (PRInt32 colIdx = 0; cell = GetNextCellInRow(row, cell); colIdx++) {
      if (IsARIASelected(cell))
        selCells.AppendElement(rowIdx * colCount + colIdx);
    }
  }

  PRUint32 selCellsCount = selCells.Length();
  if (!selCellsCount)
    return NS_OK;

  *aCells = static_cast<PRInt32*>(
    nsMemory::Clone(selCells.Elements(), selCellsCount * sizeof(PRInt32)));
  NS_ENSURE_TRUE(*aCells, NS_ERROR_OUT_OF_MEMORY);

  *aCellsCount = selCellsCount;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSelectedColumns(PRUint32 *aColumnsCount,
                                         PRInt32 **aColumns)
{
  NS_ENSURE_ARG_POINTER(aColumns);

  return GetSelectedColumnsArray(aColumnsCount, aColumns);
}

NS_IMETHODIMP
nsARIAGridAccessible::GetSelectedRows(PRUint32 *aRowsCount, PRInt32 **aRows)
{
  NS_ENSURE_ARG_POINTER(aRowsCount);
  *aRowsCount = 0;
  NS_ENSURE_ARG_POINTER(aRows);
  *aRows = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  PRInt32 rowCount = 0;
  GetRows(&rowCount);
  if (!rowCount)
    return NS_OK;

  nsTArray<PRInt32> selRows(rowCount);

  nsCOMPtr<nsIAccessible> row;
  for (PRInt32 rowIdx = 0; row = GetNextRow(row); rowIdx++) {
    if (IsARIASelected(row)) {
      selRows.AppendElement(rowIdx);
      continue;
    }

    nsCOMPtr<nsIAccessible> cell = GetNextCellInRow(row);
    if (!cell)
      continue;

    PRBool isRowSelected = PR_TRUE;
    do {
      if (!IsARIASelected(cell)) {
        isRowSelected = PR_FALSE;
        break;
      }
    } while ((cell = GetNextCellInRow(row, cell)));

    if (isRowSelected)
      selRows.AppendElement(rowIdx);
  }

  PRUint32 selRowsCount = selRows.Length();
  if (!selRowsCount)
    return NS_OK;

  *aRows = static_cast<PRInt32*>(
    nsMemory::Clone(selRows.Elements(), selRowsCount * sizeof(PRInt32)));
  NS_ENSURE_TRUE(*aRows, NS_ERROR_OUT_OF_MEMORY);

  *aRowsCount = selRowsCount;
  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::SelectRow(PRInt32 aRow)
{
  NS_ENSURE_ARG(IsValidRow(aRow));

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row;
  for (PRInt32 rowIdx = 0; row = GetNextRow(row); rowIdx++) {
    nsresult rv = SetARIASelected(row, rowIdx == aRow);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::SelectColumn(PRInt32 aColumn)
{
  NS_ENSURE_ARG(IsValidColumn(aColumn));

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row;
  while ((row = GetNextRow(row))) {
    // Unselect all cells in the row.
    nsresult rv = SetARIASelected(row, PR_FALSE);
    NS_ENSURE_SUCCESS(rv, rv);

    // Select cell at the column index.
    nsCOMPtr<nsIAccessible> cell = GetCellInRowAt(row, aColumn);
    if (cell) {
      rv = SetARIASelected(cell, PR_TRUE);
      NS_ENSURE_SUCCESS(rv, rv);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::UnselectRow(PRInt32 aRow)
{
  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row = GetRowAt(aRow);
  NS_ENSURE_ARG(row);

  return SetARIASelected(row, PR_FALSE);
}

NS_IMETHODIMP
nsARIAGridAccessible::UnselectColumn(PRInt32 aColumn)
{
  NS_ENSURE_ARG(IsValidColumn(aColumn));

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row;
  while ((row = GetNextRow(row))) {
    nsCOMPtr<nsIAccessible> cell = GetCellInRowAt(row, aColumn);
    if (cell) {
      nsresult rv = SetARIASelected(cell, PR_FALSE);
      NS_ENSURE_SUCCESS(rv, rv);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsARIAGridAccessible::IsProbablyForLayout(PRBool *aIsProbablyForLayout)
{
  NS_ENSURE_ARG_POINTER(aIsProbablyForLayout);
  *aIsProbablyForLayout = PR_FALSE;

  return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////
// Protected

PRBool
nsARIAGridAccessible::IsValidRow(PRInt32 aRow)
{
  if (aRow < 0)
    return PR_FALSE;
  
  PRInt32 rowCount = 0;
  GetRows(&rowCount);
  return aRow < rowCount;
}

PRBool
nsARIAGridAccessible::IsValidColumn(PRInt32 aColumn)
{
  if (aColumn < 0)
    return PR_FALSE;

  PRInt32 colCount = 0;
  GetColumns(&colCount);
  return aColumn < colCount;
}

PRBool
nsARIAGridAccessible::IsValidRowNColumn(PRInt32 aRow, PRInt32 aColumn)
{
  if (aRow < 0 || aColumn < 0)
    return PR_FALSE;
  
  PRInt32 rowCount = 0;
  GetRows(&rowCount);
  if (aRow >= rowCount)
    return PR_FALSE;

  PRInt32 colCount = 0;
  GetColumns(&colCount);
  return aColumn < colCount;
}

already_AddRefed<nsIAccessible>
nsARIAGridAccessible::GetRowAt(PRInt32 aRow)
{
  PRInt32 rowIdx = aRow;
  nsCOMPtr<nsIAccessible> row(GetNextRow());
  while (rowIdx != 0 && (row = GetNextRow(row)))
    rowIdx--;

  return row.forget();
}

already_AddRefed<nsIAccessible>
nsARIAGridAccessible::GetCellInRowAt(nsIAccessible *aRow, PRInt32 aColumn)
{
  PRInt32 colIdx = aColumn;
  nsCOMPtr<nsIAccessible> cell(GetNextCellInRow(aRow));
  while (colIdx != 0 && (cell = GetNextCellInRow(aRow, cell)))
    colIdx--;

  return cell.forget();
}

already_AddRefed<nsIAccessible>
nsARIAGridAccessible::GetNextRow(nsIAccessible *aRow)
{
  nsCOMPtr<nsIAccessible> nextRow, tmpAcc;
  if (!aRow)
    GetFirstChild(getter_AddRefs(nextRow));
  else
    aRow->GetNextSibling(getter_AddRefs(nextRow));

  while (nextRow) {
    if (nsAccUtils::Role(nextRow) == nsIAccessibleRole::ROLE_ROW)
      return nextRow.forget();

    nextRow->GetNextSibling(getter_AddRefs(tmpAcc));
    tmpAcc.swap(nextRow);
  }

  return nsnull;
}

already_AddRefed<nsIAccessible>
nsARIAGridAccessible::GetNextCellInRow(nsIAccessible *aRow, nsIAccessible *aCell)
{
  if (!aRow)
    return nsnull;

  nsCOMPtr<nsIAccessible> nextCell, tmpAcc;
  if (!aCell)
    aRow->GetFirstChild(getter_AddRefs(nextCell));
  else
    aCell->GetNextSibling(getter_AddRefs(nextCell));

  while (nextCell) {
    PRUint32 role = nsAccUtils::Role(nextCell);
    if (role == nsIAccessibleRole::ROLE_GRID_CELL ||
        role == nsIAccessibleRole::ROLE_ROWHEADER ||
        role == nsIAccessibleRole::ROLE_COLUMNHEADER)
      return nextCell.forget();

    nextCell->GetNextSibling(getter_AddRefs(tmpAcc));
    tmpAcc.swap(nextCell);
  }

  return nsnull;
}

PRBool
nsARIAGridAccessible::IsARIASelected(nsIAccessible *aAccessible)
{
  nsRefPtr<nsAccessible> acc = nsAccUtils::QueryAccessible(aAccessible);
  nsCOMPtr<nsIDOMNode> node;
  acc->GetDOMNode(getter_AddRefs(node));
  NS_ASSERTION(node, "No DOM node!");

  if (node) {
    nsCOMPtr<nsIContent> content(do_QueryInterface(node));
    if (content->AttrValueIs(kNameSpaceID_None,
                             nsAccessibilityAtoms::aria_selected,
                             nsAccessibilityAtoms::_true, eCaseMatters))
      return PR_TRUE;
  }

  return PR_FALSE;
}

nsresult
nsARIAGridAccessible::SetARIASelected(nsIAccessible *aAccessible,
                                      PRBool aIsSelected, PRBool aNotify)
{
  nsRefPtr<nsAccessible> acc = nsAccUtils::QueryAccessible(aAccessible);
  nsCOMPtr<nsIDOMNode> node;
  acc->GetDOMNode(getter_AddRefs(node));
  NS_ENSURE_STATE(node);

  nsCOMPtr<nsIContent> content(do_QueryInterface(node));

  nsresult rv = NS_OK;
  if (aIsSelected)
    rv = content->SetAttr(kNameSpaceID_None, nsAccessibilityAtoms::aria_selected,
                          NS_LITERAL_STRING("true"), aNotify);
  else
    rv = content->UnsetAttr(kNameSpaceID_None,
                            nsAccessibilityAtoms::aria_selected, aNotify);

  NS_ENSURE_SUCCESS(rv, rv);

  // No "smart" select/unselect for internal call.
  if (!aNotify)
    return NS_OK;

  // If row or cell accessible was selected then we're able to not bother about
  // selection of its cells or its row because our algorithm is row oriented,
  // i.e. we check selection on row firstly and then on cells.
  if (aIsSelected)
    return NS_OK;

  PRUint32 role = nsAccUtils::Role(aAccessible);

  // If the given accessible is row that was unselected then remove
  // aria-selected from cell accessible.
  if (role == nsIAccessibleRole::ROLE_ROW) {
    nsCOMPtr<nsIAccessible> cell;
    while ((cell = GetNextCellInRow(aAccessible, cell))) {
      rv = SetARIASelected(cell, PR_FALSE, PR_FALSE);
      NS_ENSURE_SUCCESS(rv, rv);
    }
    return NS_OK;
  }

  // If the given accessible is cell that was unselected and its row is selected
  // then remove aria-selected from row and put aria-selected on
  // siblings cells.
  if (role == nsIAccessibleRole::ROLE_GRID_CELL ||
      role == nsIAccessibleRole::ROLE_ROWHEADER ||
      role == nsIAccessibleRole::ROLE_COLUMNHEADER) {
    nsCOMPtr<nsIAccessible> row;
    aAccessible->GetParent(getter_AddRefs(row));

    if (nsAccUtils::Role(row) == nsIAccessibleRole::ROLE_ROW &&
        IsARIASelected(row)) {
      rv = SetARIASelected(row, PR_FALSE, PR_FALSE);
      NS_ENSURE_SUCCESS(rv, rv);

      nsCOMPtr<nsIAccessible> cell;
      while ((cell = GetNextCellInRow(row, cell))) {
        if (cell != aAccessible) {
          rv = SetARIASelected(cell, PR_TRUE, PR_FALSE);
          NS_ENSURE_SUCCESS(rv, rv);
        }
      }
    }
  }

  return NS_OK;
}

nsresult
nsARIAGridAccessible::GetSelectedColumnsArray(PRUint32 *aColumnsCount,
                                              PRInt32 **aColumns)
{
  NS_ENSURE_ARG_POINTER(aColumnsCount);
  *aColumnsCount = 0;
  if (aColumns)
    *aColumns = nsnull;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIAccessible> row = GetNextRow();
  if (!row)
    return NS_OK;

  PRInt32 colCount = 0;
  GetColumns(&colCount);
  if (!colCount)
    return NS_OK;

  PRInt32 selColCount = colCount;

  nsTArray<PRBool> isColSelArray(selColCount);
  isColSelArray.AppendElements(selColCount);
  for (PRInt32 i = 0; i < selColCount; i++)
    isColSelArray[i] = PR_TRUE;

  do {
    if (IsARIASelected(row))
      continue;

    PRInt32 colIdx = 0;
    nsCOMPtr<nsIAccessible> cell;
    for (colIdx = 0; cell = GetNextCellInRow(row, cell); colIdx++) {
      if (isColSelArray.SafeElementAt(colIdx, PR_FALSE) &&
          !IsARIASelected(cell)) {
        isColSelArray[colIdx] = PR_FALSE;
        selColCount--;
      }
    }
  } while ((row = GetNextRow(row)));

  if (!selColCount)
    return NS_OK;

  if (!aColumns) {
    *aColumnsCount = selColCount;
    return NS_OK;
  }

  *aColumns = static_cast<PRInt32*>(
    nsMemory::Alloc(selColCount * sizeof(PRInt32)));
  NS_ENSURE_TRUE(*aColumns, NS_ERROR_OUT_OF_MEMORY);

  *aColumnsCount = selColCount;
  for (PRInt32 colIdx = 0, idx = 0; colIdx < colCount; colIdx++) {
    if (isColSelArray[colIdx])
      (*aColumns)[idx++] = colIdx;
  }

  return NS_OK;
}


////////////////////////////////////////////////////////////////////////////////
// nsARIAGridCellAccessible
////////////////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////////////////
// Constructor

nsARIAGridCellAccessible::nsARIAGridCellAccessible(nsIDOMNode* aDomNode,
                                                   nsIWeakReference* aShell) :
  nsHyperTextAccessibleWrap(aDomNode, aShell)
{
}

////////////////////////////////////////////////////////////////////////////////
// nsISupports

NS_IMPL_ISUPPORTS_INHERITED0(nsARIAGridCellAccessible,
                             nsHyperTextAccessible)

////////////////////////////////////////////////////////////////////////////////
// nsAccessible

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

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

  nsCOMPtr<nsIAccessible> thisRow;
  GetParent(getter_AddRefs(thisRow));
  if (nsAccUtils::Role(thisRow) != nsIAccessibleRole::ROLE_ROW)
    return NS_OK;

  PRInt32 colIdx = 0, colCount = 0;
  nsCOMPtr<nsIAccessible> child, nextChild;
  thisRow->GetFirstChild(getter_AddRefs(child));
  while (child) {
    if (child == this)
      colIdx = colCount;

    PRUint32 role = nsAccUtils::Role(child);
    if (role == nsIAccessibleRole::ROLE_GRID_CELL ||
        role == nsIAccessibleRole::ROLE_ROWHEADER ||
        role == nsIAccessibleRole::ROLE_COLUMNHEADER)
      colCount++;

    child->GetNextSibling(getter_AddRefs(nextChild));
    child.swap(nextChild);
  }

  nsCOMPtr<nsIAccessible> table;
  thisRow->GetParent(getter_AddRefs(table));
  if (nsAccUtils::Role(table) != nsIAccessibleRole::ROLE_TABLE &&
      nsAccUtils::Role(table) != nsIAccessibleRole::ROLE_TREE_TABLE)
    return NS_OK;

  PRInt32 rowIdx = 0;
  table->GetFirstChild(getter_AddRefs(child));
  while (child && child != thisRow) {
    if (nsAccUtils::Role(child) == nsIAccessibleRole::ROLE_ROW)
      rowIdx++;

    child->GetNextSibling(getter_AddRefs(nextChild));
    child.swap(nextChild);
  }

  PRInt32 idx = rowIdx * colCount + colIdx;

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

  return NS_OK;
}