a11y: Implement QAccessibleSelectionInterface for item views

In QAccessibleTable's model, cells (rather than rows or columns)
are direct children of the table and therefore items handled in
the selection, so forward/make use of the corresponding methods
that handle cells.
(In QAccessibleTable::select and QAccessibleTable::unselect,
cast the child cell to QAccessibleTableCell*, as is already
done in QAccessibleTable::indexOfChild and
QAccessibleTree::indexOfChild.)

This can be tested e.g. by calling the methods from the
AT-SPI Selection interface using Accerciser and the
"interview" example
(qtbase/examples/widgets/itemviews/interview/interview).

Change-Id: Ic650a8a01b56653cae4f2cb26e28aed4dc566a7e
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

src/widgets/accessible/itemviews.cpp

@@ -366,6 +366,85 @@ bool QAccessibleTable::unselectColumn(int column)
     return true;
 }
 
+int QAccessibleTable::selectedItemCount() const
+{
+    return selectedCellCount();
+}
+
+QList<QAccessibleInterface*> QAccessibleTable::selectedItems() const
+{
+    return selectedCells();
+}
+
+bool QAccessibleTable::isSelected(QAccessibleInterface *childCell) const
+{
+    if (!childCell || childCell->parent() != this) {
+        qWarning() << "QAccessibleTable::isSelected: Accessible interface must be a direct child of the table interface.";
+        return false;
+    }
+
+    const QAccessibleTableCellInterface *cell = childCell->tableCellInterface();
+    if (cell)
+        return cell->isSelected();
+
+    return false;
+}
+
+bool QAccessibleTable::select(QAccessibleInterface *childCell)
+{
+    if (!childCell || childCell->parent() != this) {
+        qWarning() << "QAccessibleTable::select: Accessible interface must be a direct child of the table interface.";
+        return false;
+    }
+
+    if (!childCell->tableCellInterface()) {
+        qWarning() << "QAccessibleTable::select: Accessible interface doesn't implement table cell interface.";
+        return false;
+    }
+
+    if (childCell->role() == QAccessible::Cell || childCell->role() == QAccessible::ListItem || childCell->role() == QAccessible::TreeItem) {
+        QAccessibleTableCell* cell = static_cast<QAccessibleTableCell*>(childCell);
+        cell->selectCell();
+        return true;
+    }
+
+    return false;
+}
+
+bool QAccessibleTable::unselect(QAccessibleInterface *childCell)
+{
+    if (!childCell || childCell->parent() != this) {
+        qWarning() << "QAccessibleTable::select: Accessible interface must be a direct child of the table interface.";
+        return false;
+    }
+
+    if (!childCell->tableCellInterface()) {
+        qWarning() << "QAccessibleTable::unselect: Accessible interface doesn't implement table cell interface.";
+        return false;
+    }
+
+    if (childCell->role() == QAccessible::Cell || childCell->role() == QAccessible::ListItem || childCell->role() == QAccessible::TreeItem) {
+        QAccessibleTableCell* cell = static_cast<QAccessibleTableCell*>(childCell);
+        cell->unselectCell();
+        return true;
+    }
+
+    return false;
+}
+
+bool QAccessibleTable::selectAll()
+{
+    view()->selectAll();
+    return true;
+}
+
+bool QAccessibleTable::clear()
+{
+    view()->selectionModel()->clearSelection();
+    return true;
+}
+
+
 QAccessible::Role QAccessibleTable::role() const
 {
     return m_role;
@@ -533,6 +612,8 @@ QAccessibleInterface *QAccessibleTable::child(int logicalIndex) const
 
 void *QAccessibleTable::interface_cast(QAccessible::InterfaceType t)
 {
+    if (t == QAccessible::SelectionInterface)
+       return static_cast<QAccessibleSelectionInterface*>(this);
     if (t == QAccessible::TableInterface)
        return static_cast<QAccessibleTableInterface*>(this);
    return nullptr;

src/widgets/accessible/itemviews_p.h

@@ -31,7 +31,7 @@ QT_BEGIN_NAMESPACE
 class QAccessibleTableCell;
 class QAccessibleTableHeaderCell;
 
-class QAccessibleTable :public QAccessibleTableInterface, public QAccessibleObject
+class QAccessibleTable :public QAccessibleTableInterface, public QAccessibleSelectionInterface, public QAccessibleObject
 {
 public:
     explicit QAccessibleTable(QWidget *w);
@@ -75,6 +75,15 @@ public:
     virtual bool unselectRow(int row) override;
     virtual bool unselectColumn(int column) override;
 
+    // QAccessibleSelectionInterface
+    virtual int selectedItemCount() const override;
+    virtual QList<QAccessibleInterface*> selectedItems() const override;
+    virtual bool isSelected(QAccessibleInterface *childCell) const override;
+    virtual bool select(QAccessibleInterface *childCell) override;
+    virtual bool unselect(QAccessibleInterface *childCell) override;
+    virtual bool selectAll() override;
+    virtual bool clear() override;
+
     QAbstractItemView *view() const;
 
     void modelChange(QAccessibleTableModelChangeEvent *event) override;