/**
* Computes the number of results.
*
* @param qc query context (may be @code null)
* @return number of results
*/
private long size(final QueryContext qc) {
final Value rt = initial(qc);
// skip computation if value is not a document node
if (rt == null || rt.type != NodeType.DOC) return -1;
final Data data = rt.data();
// skip computation if no database instance is available, is out-of-date or
// if context does not contain all database nodes
if (data == null || !data.meta.uptodate || data.resources.docs().size() != rt.size()) return -1;
ArrayList<PathNode> nodes = data.paths.root();
long m = 1;
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
final Step curr = axisStep(s);
if (curr != null) {
nodes = curr.nodes(nodes, data);
if (nodes == null) return -1;
} else if (s + 1 == sl) {
m = steps[s].size();
} else {
// stop if a non-axis step is not placed last
return -1;
}
}
long sz = 0;
for (final PathNode pn : nodes) sz += pn.stats.count;
return sz * m;
}
/**
* Returns the path nodes that will result from this path.
*
* @param qc query context
* @return path nodes, or {@code null} if nodes cannot be evaluated
*/
public final ArrayList<PathNode> pathNodes(final QueryContext qc) {
final Value init = initial(qc);
final Data data = init != null && init.type == NodeType.DOC ? init.data() : null;
if (data == null || !data.meta.uptodate) return null;
ArrayList<PathNode> nodes = data.paths.root();
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
final Step curr = axisStep(s);
if (curr == null) return null;
nodes = curr.nodes(nodes, data);
if (nodes == null) return null;
}
return nodes;
}