/**
* Returns the initial context value of a path or {@code null}.
*
* @param qc query context (may be @code null)
* @return root
*/
private Value initial(final QueryContext qc) {
// current context value
final Value v = qc != null ? qc.value : null;
// no root or context expression: return context
if (root == null || root instanceof Context) return v;
// root reference
if (root instanceof Root) return v != null && v instanceof Item ? Root.root(v) : v;
// root is value: return root
if (root.isValue()) return (Value) root;
// data reference
final Data d = root.data();
if (d != null) return new DBNode(d, 0, Data.ELEM);
// otherwise, return null
return null;
}
@Override
public Data data() {
if (root != null) {
// data reference
final Data data = root.data();
if (data != null) {
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
if (axisStep(s) == null) return null;
}
return data;
}
}
return null;
}