/**
* 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// skip computation if no database instance is available, is out-of-date or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;
}
/**
* Checks the response to an HTTP request.
*
* @param v query result
* @param itemsCount expected number of items
* @param expStatus expected status
*/
private static void checkResponse(final Value v, final int itemsCount, final int expStatus) {
assertEquals(itemsCount, v.size());
assertTrue(v.itemAt(0) instanceof FElem);
final FElem response = (FElem) v.itemAt(0);
assertNotNull(response.attributes());
if (!eq(response.attribute(STATUS), token(expStatus))) {
fail("Expected: " + expStatus + "\nFound: " + response);
}
}
/**
* Returns the root of the current context or {@code null}.
*
* @param ctx query context
* @return root
*/
final Value root(final QueryContext ctx) {
final Value v = ctx != null ? ctx.value : null;
// no root specified: return context, if it does not reference a document
// as e.g. happens in //a(b|c)
if (root == null) return v == null || v.type != NodeType.DOC ? v : null;
// root is value: return root
if (root.isValue()) return (Value) root;
// no root reference, no context: return null
if (!(root instanceof Root) || v == null) return null;
// return context sequence or root of current context
return v.size() == 1 ? Root.root(v) : v;
}
/**
* Returns a parameter.
*
* @param value value
* @param name name
* @param declared variable declaration flags
* @return parameter
* @throws QueryException HTTP exception
*/
private RestXqParam param(final Value value, final QNm name, final boolean[] declared)
throws QueryException {
// [CG] RESTXQ: allow identical field names?
final long vs = value.size();
if (vs < 2) error(ANN_PARAMS, "%", name.string(), 2);
// name of parameter
final String key = toString(value.itemAt(0), name);
// variable template
final QNm qnm = checkVariable(toString(value.itemAt(1), name), declared);
// default value
final ValueBuilder vb = new ValueBuilder();
for (int v = 2; v < vs; v++) vb.add(value.itemAt(v));
return new RestXqParam(qnm, key, vb.value());
}
/**
* Evaluates the specified query.
*
* @param query query
* @return success flag
*/
final boolean query(final String query) {
final Performance p = new Performance();
String error;
if (exception != null) {
error = Util.message(exception);
} else {
try {
long hits = 0;
final boolean run = options.get(MainOptions.RUNQUERY);
final boolean serial = options.get(MainOptions.SERIALIZE);
final int runs = Math.max(1, options.get(MainOptions.RUNS));
for (int r = 0; r < runs; ++r) {
// reuse existing processor instance
if (r != 0) qp = null;
qp(query, context);
parse(p);
if (r == 0) plan(false);
qp.compile();
info.compiling += p.time();
if (r == 0) plan(true);
if (!run) continue;
final PrintOutput po = r == 0 && serial ? out : new NullOutput();
try (final Serializer ser = qp.getSerializer(po)) {
if (maxResults >= 0) {
result = qp.cache(maxResults);
info.evaluating += p.time();
result.serialize(ser);
hits = result.size();
} else {
hits = 0;
final Iter ir = qp.iter();
info.evaluating += p.time();
for (Item it; (it = ir.next()) != null; ) {
ser.serialize(it);
++hits;
checkStop();
}
}
}
qp.close();
info.serializing += p.time();
}
// dump some query info
// out.flush();
// remove string list if global locking is used and if query is updating
if (soptions.get(StaticOptions.GLOBALLOCK) && qp.updating) {
info.readLocked = null;
info.writeLocked = null;
}
return info(info.toString(qp, out.size(), hits, options.get(MainOptions.QUERYINFO)));
} catch (final QueryException | IOException ex) {
exception = ex;
error = Util.message(ex);
} catch (final ProcException ex) {
error = INTERRUPTED;
} catch (final StackOverflowError ex) {
Util.debug(ex);
error = BASX_STACKOVERFLOW.desc;
} catch (final RuntimeException ex) {
extError("");
Util.debug(info());
throw ex;
} finally {
// close processor after exceptions
if (qp != null) qp.close();
}
}
return extError(error);
}
/**
* Adds items to the specified list.
*
* @param value value
* @param name name
* @param list list to add values to
* @throws QueryException HTTP exception
*/
private void strings(final Value value, final QNm name, final StringList list)
throws QueryException {
final long vs = value.size();
for (int v = 0; v < vs; v++) list.add(toString(value.itemAt(v), name));
}