static AccessibilityObject* listObjectForSelection(AtkSelection* selection)
{
    AccessibilityObject* coreSelection = core(selection);

    // Only list boxes and menu lists supported so far.
    if (!coreSelection->isListBox() && !coreSelection->isMenuList())
        return 0;

    // For list boxes the list object is just itself.
    if (coreSelection->isListBox())
        return coreSelection;

    // For menu lists we need to return the first accessible child,
    // with role MenuListPopupRole, since that's the one holding the list
    // of items with role MenuListOptionRole.
    AccessibilityObject::AccessibilityChildrenVector children = coreSelection->children();
    if (!children.size())
        return 0;

    AccessibilityObject* listObject = children.at(0).get();
    if (!listObject->isMenuListPopup())
        return 0;

    return listObject;
}

static gint webkitAccessibleSelectionGetSelectionCount(AtkSelection* selection)
{
    g_return_val_if_fail(ATK_SELECTION(selection), 0);
    returnValIfWebKitAccessibleIsInvalid(WEBKIT_ACCESSIBLE(selection), 0);

    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection || !coreSelection->isAccessibilityRenderObject())
        return 0;

    if (coreSelection->isListBox()) {
        AccessibilityObject::AccessibilityChildrenVector selectedItems;
        coreSelection->selectedChildren(selectedItems);
        return static_cast<gint>(selectedItems.size());
    }

    if (coreSelection->isMenuList()) {
        RenderObject* renderer = coreSelection->renderer();
        if (!renderer)
            return 0;

        int selectedIndex = downcast<HTMLSelectElement>(renderer->node())->selectedIndex();
        return selectedIndex >= 0 && selectedIndex < static_cast<int>(downcast<HTMLSelectElement>(renderer->node())->listItems().size());
    }

    return 0;
}

static gint webkitAccessibleGetIndexInParent(AtkObject* object)
{
    AccessibilityObject* coreObject = core(object);
    AccessibilityObject* parent = coreObject->parentObjectUnignored();

    if (!parent && isRootObject(coreObject)) {
        AtkObject* atkParent = atkParentOfRootObject(object);
        if (!atkParent)
            return -1;

        unsigned count = atk_object_get_n_accessible_children(atkParent);
        for (unsigned i = 0; i < count; ++i) {
            AtkObject* child = atk_object_ref_accessible_child(atkParent, i);
            bool childIsObject = child == object;
            g_object_unref(child);
            if (childIsObject)
                return i;
        }
    }

    // Need to calculate the index of the cell in the table, as
    // rows won't be exposed to assistive technologies in GTK.
    if (parent && parent->isTableRow() && coreObject->isTableCell())
        return getIndexInParentForCellInRow(coreObject);

    AccessibilityObject::AccessibilityChildrenVector children = parent->children();
    unsigned count = children.size();
    for (unsigned i = 0; i < count; ++i) {
        if (children[i] == coreObject)
            return i;
    }

    return -1;
}

static AccessibilityObject* optionFromSelection(AtkSelection* selection, gint index)
{
    // i is the ith selection as opposed to the ith child.

    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection || !coreSelection->isAccessibilityRenderObject() || index < 0)
        return 0;

    AccessibilityObject::AccessibilityChildrenVector selectedItems;
    if (coreSelection->isListBox())
        coreSelection->selectedChildren(selectedItems);
    else if (coreSelection->isMenuList()) {
        RenderObject* renderer = coreSelection->renderer();
        if (!renderer)
            return 0;

        HTMLSelectElement* selectNode = toHTMLSelectElement(renderer->node());
        int selectedIndex = selectNode->selectedIndex();
        const Vector<HTMLElement*> listItems = selectNode->listItems();

        if (selectedIndex < 0 || selectedIndex >= static_cast<int>(listItems.size()))
            return 0;

        return optionFromList(selection, selectedIndex);
    }

    if (index < static_cast<gint>(selectedItems.size()))
        return selectedItems.at(index).get();

    return 0;
}

static gint cellIndex(AccessibilityTableCell* axCell, AccessibilityTable* axTable)
{
    // Calculate the cell's index as if we had a traditional Gtk+ table in
    // which cells are all direct children of the table, arranged row-first.
    AccessibilityObject::AccessibilityChildrenVector allCells;
    axTable->cells(allCells);
    AccessibilityObject::AccessibilityChildrenVector::iterator position;
    position = std::find(allCells.begin(), allCells.end(), axCell);
    if (position == allCells.end())
        return -1;
    return position - allCells.begin();
}

static AccessibilityTableCell* cellAtIndex(AtkTable* table, gint index)
{
    AccessibilityObject* accTable = core(table);
    if (accTable->isAccessibilityRenderObject()) {
        AccessibilityObject::AccessibilityChildrenVector allCells;
        toAccessibilityTable(accTable)->cells(allCells);
        if (0 <= index && static_cast<unsigned>(index) < allCells.size()) {
            AccessibilityObject* accCell = allCells.at(index).get();
            return toAccessibilityTableCell(accCell);
        }
    }
    return 0;
}

static gint webkit_accessible_get_index_in_parent(AtkObject* object)
{
    AccessibilityObject* coreObject = core(object);
    AccessibilityObject* parent = coreObject->parentObjectUnignored();

    g_return_val_if_fail(parent, 0);

    AccessibilityObject::AccessibilityChildrenVector children = parent->children();
    unsigned count = children.size();
    for (unsigned i = 0; i < count; ++i) {
        if (children[i] == coreObject)
            return i;
    }

    return 0;
}

static gboolean webkitAccessibleSelectionClearSelection(AtkSelection* selection)
{
    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection)
        return FALSE;

    AccessibilityObject::AccessibilityChildrenVector selectedItems;
    if (coreSelection->isListBox() || coreSelection->isMenuList()) {
        // Set the list of selected items to an empty list; then verify that it worked.
        AccessibilityListBox* listBox = static_cast<AccessibilityListBox*>(coreSelection);
        listBox->setSelectedChildren(selectedItems);
        listBox->selectedChildren(selectedItems);
        return !selectedItems.size();
    }
    return FALSE;
}

static AtkObject* webkit_accessible_table_get_row_header(AtkTable* table, gint row)
{
    AccessibilityObject* accTable = core(table);
    if (accTable->isAccessibilityRenderObject()) {
        AccessibilityObject::AccessibilityChildrenVector allRowHeaders;
        static_cast<AccessibilityTable*>(accTable)->rowHeaders(allRowHeaders);

        unsigned rowCount = allRowHeaders.size();
        for (unsigned k = 0; k < rowCount; ++k) {
            AccessibilityObject* rowObject = allRowHeaders[k]->parentObject();
            if (static_cast<AccessibilityTableRow*>(rowObject)->rowIndex() == row)
                return allRowHeaders[k]->wrapper();
        }
    }
    return 0;
}

static gboolean webkitAccessibleSelectionSelectAllSelection(AtkSelection* selection)
{
    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection || !coreSelection->isMultiSelectable())
        return FALSE;

    AccessibilityObject::AccessibilityChildrenVector children = coreSelection->children();
    if (coreSelection->isListBox()) {
        AccessibilityListBox* listBox = static_cast<AccessibilityListBox*>(coreSelection);
        listBox->setSelectedChildren(children);
        AccessibilityObject::AccessibilityChildrenVector selectedItems;
        listBox->selectedChildren(selectedItems);
        return selectedItems.size() == children.size();
    }

    return FALSE;
}

static AtkObject* webkitAccessibleTableGetRowHeader(AtkTable* table, gint row)
{
    AccessibilityObject* accTable = core(table);
    if (accTable->isAccessibilityRenderObject()) {
        AccessibilityObject::AccessibilityChildrenVector allRowHeaders;
        static_cast<AccessibilityTable*>(accTable)->rowHeaders(allRowHeaders);
        unsigned rowCount = allRowHeaders.size();
        for (unsigned k = 0; k < rowCount; ++k) {
            pair<unsigned, unsigned> rowRange;
            AccessibilityTableCell* cell = static_cast<AccessibilityTableCell*>(allRowHeaders.at(k).get());
            cell->rowIndexRange(rowRange);
            if (rowRange.first <= static_cast<unsigned>(row) && static_cast<unsigned>(row) < rowRange.first + rowRange.second)
                return allRowHeaders[k]->wrapper();
        }
    }
    return 0;
}

static AccessibilityObject* optionFromList(AtkSelection* selection, gint index)
{
    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection || index < 0)
        return 0;

    // Need to select the proper list object depending on the type.
    AccessibilityObject* listObject = listObjectForSelection(selection);
    if (!listObject)
        return 0;

    AccessibilityObject::AccessibilityChildrenVector options = listObject->children();
    if (index < static_cast<gint>(options.size()))
        return options.at(index).get();

    return 0;
}

void AccessibilityTable::cells(AccessibilityObject::AccessibilityChildrenVector& cells)
{
    if (!m_renderer)
        return;
    
    updateChildrenIfNecessary();
    
    for (const auto& row : m_rows)
        cells.appendVector(row->children());
}

static gboolean webkitAccessibleSelectionClearSelection(AtkSelection* selection)
{
    g_return_val_if_fail(ATK_SELECTION(selection), FALSE);
    returnValIfWebKitAccessibleIsInvalid(WEBKIT_ACCESSIBLE(selection), FALSE);

    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection)
        return FALSE;

    AccessibilityObject::AccessibilityChildrenVector selectedItems;
    if (coreSelection->isListBox() || coreSelection->isMenuList()) {
        // Set the list of selected items to an empty list; then verify that it worked.
        AccessibilityListBox* listBox = toAccessibilityListBox(coreSelection);
        listBox->setSelectedChildren(selectedItems);
        listBox->selectedChildren(selectedItems);
        return !selectedItems.size();
    }
    return FALSE;
}

void AccessibilityTable::cells(AccessibilityObject::AccessibilityChildrenVector& cells)
{
    if (!m_renderer)
        return;
    
    updateChildrenIfNecessary();
    
    for (size_t row = 0; row < m_rows.size(); ++row)
        cells.appendVector(m_rows[row]->children());
}

static gboolean webkitAccessibleSelectionSelectAllSelection(AtkSelection* selection)
{
    g_return_val_if_fail(ATK_SELECTION(selection), FALSE);
    returnValIfWebKitAccessibleIsInvalid(WEBKIT_ACCESSIBLE(selection), FALSE);

    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection || !coreSelection->isMultiSelectable())
        return FALSE;

    if (coreSelection->isListBox()) {
        const AccessibilityObject::AccessibilityChildrenVector& children = coreSelection->children();
        AccessibilityListBox* listBox = toAccessibilityListBox(coreSelection);
        listBox->setSelectedChildren(children);
        AccessibilityObject::AccessibilityChildrenVector selectedItems;
        listBox->selectedChildren(selectedItems);
        return selectedItems.size() == children.size();
    }

    return FALSE;
}

static AtkObject* webkitAccessibleTableGetRowHeader(AtkTable* table, gint row)
{
    g_return_val_if_fail(ATK_TABLE(table), 0);
    returnValIfWebKitAccessibleIsInvalid(WEBKIT_ACCESSIBLE(table), 0);

    AccessibilityObject* accTable = core(table);
    if (accTable->isAccessibilityRenderObject()) {
        AccessibilityObject::AccessibilityChildrenVector allRowHeaders;
        toAccessibilityTable(accTable)->rowHeaders(allRowHeaders);
        unsigned rowCount = allRowHeaders.size();
        for (unsigned k = 0; k < rowCount; ++k) {
            pair<unsigned, unsigned> rowRange;
            AccessibilityTableCell* cell = toAccessibilityTableCell(allRowHeaders.at(k).get());
            cell->rowIndexRange(rowRange);
            if (rowRange.first <= static_cast<unsigned>(row) && static_cast<unsigned>(row) < rowRange.first + rowRange.second)
                return allRowHeaders[k]->wrapper();
        }
    }
    return 0;
}

void AccessibilityTable::cells(AccessibilityObject::AccessibilityChildrenVector& cells)
{
    if (!m_renderer)
        return;
    
    updateChildrenIfNecessary();
    
    int numRows = m_rows.size();
    for (int row = 0; row < numRows; ++row) {
        AccessibilityChildrenVector rowChildren = m_rows[row]->children();
        cells.append(rowChildren);
    }
}

static gint webkitAccessibleSelectionGetSelectionCount(AtkSelection* selection)
{
    AccessibilityObject* coreSelection = core(selection);
    if (!coreSelection || !coreSelection->isAccessibilityRenderObject())
        return 0;

    if (coreSelection->isListBox()) {
        AccessibilityObject::AccessibilityChildrenVector selectedItems;
        coreSelection->selectedChildren(selectedItems);
        return static_cast<gint>(selectedItems.size());
    }

    if (coreSelection->isMenuList()) {
        RenderObject* renderer = coreSelection->renderer();
        if (!renderer)
            return 0;

        int selectedIndex = toHTMLSelectElement(renderer->node())->selectedIndex();
        return selectedIndex >= 0 && selectedIndex < static_cast<int>(toHTMLSelectElement(renderer->node())->listItems().size());
    }

    return 0;
}

static bool childrenContainOnlyStaticText(const AccessibilityObject::AccessibilityChildrenVector& children)
{
    if (!children.size())
        return false;
    for (const auto& child : children) {
        if (child->roleValue() == AccessibilityRole::StaticText)
            continue;
        if (child->roleValue() == AccessibilityRole::Group) {
            if (!childrenContainOnlyStaticText(child->children()))
                return false;
        } else
            return false;
    }
    return true;
}