@Override
public Value value(final QueryContext ctx) throws QueryException {
final int o = (int) ctx.resources.output.size();
final Updates updates = ctx.resources.updates();
final ContextModifier tmp = updates.mod;
final TransformModifier pu = new TransformModifier();
updates.mod = pu;
try {
for (final Let fo : copies) {
final Iter ir = ctx.iter(fo.expr);
Item i = ir.next();
if (!(i instanceof ANode) || ir.next() != null) throw UPCOPYMULT.get(fo.info, fo.var.name);
// copy node to main memory data instance
i = ((ANode) i).dbCopy(ctx.context.options);
// add resulting node to variable
ctx.set(fo.var, i, info);
pu.addData(i.data());
}
final Value v = ctx.value(expr[0]);
if (!v.isEmpty()) throw BASEX_MOD.get(info);
updates.prepare();
updates.apply();
return ctx.value(expr[1]);
} finally {
ctx.resources.output.size(o);
updates.mod = tmp;
}
}
@Override
public Value value(final QueryContext qc) throws QueryException {
final FItem getKey = checkArity(exprs[1], 1, qc);
final long k = Math.min(toLong(exprs[2], qc), Integer.MAX_VALUE);
if (k < 1) return Empty.SEQ;
final Iter iter = exprs[0].iter(qc);
final MinHeap<Item, Item> heap =
new MinHeap<>(
new Comparator<Item>() {
@Override
public int compare(final Item it1, final Item it2) {
try {
return OpV.LT.eval(it1, it2, sc.collation, sc, info) ? -1 : 1;
} catch (final QueryException qe) {
throw new QueryRTException(qe);
}
}
});
try {
for (Item it; (it = iter.next()) != null; ) {
heap.insert(checkNoEmpty(getKey.invokeItem(qc, info, it)), it);
if (heap.size() > k) heap.removeMin();
}
} catch (final QueryRTException ex) {
throw ex.getCause();
}
final ValueBuilder vb = new ValueBuilder();
while (!heap.isEmpty()) vb.addFront(heap.removeMin());
return vb.value();
}
@Override
public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
final Iter ir = iter(qc);
final Item it = ir.next();
if (it == null || ir.size() == 1) return it;
final Item n = ir.next();
if (n != null) {
final ValueBuilder vb = new ValueBuilder().add(it).add(n);
if (ir.next() != null) vb.add(Str.get(DOTS));
throw SEQFOUND_X.get(info, vb.value());
}
return it;
}
@Override
public Value value(final QueryContext qc) throws QueryException {
final FItem f = checkArity(exprs[1], 1, qc);
final Iter iter = exprs[0].iter(qc);
Item it = iter.next();
if (it == null) return Empty.SEQ;
final Value v1 = f.invokeValue(qc, info, it);
it = iter.next();
if (it == null) return v1;
final ValueBuilder vb = new ValueBuilder().add(v1);
do {
vb.add(f.invokeValue(qc, info, it));
} while ((it = iter.next()) != null);
return vb.value();
}
@Override
public final Item ebv(final QueryContext qc, final InputInfo ii) throws QueryException {
final Item it;
if (seqType().zeroOrOne()) {
it = item(qc, info);
} else {
final Iter ir = iter(qc);
it = ir.next();
if (it != null && !(it instanceof ANode)) {
final Item n = ir.next();
if (n != null) {
final ValueBuilder vb = new ValueBuilder().add(it).add(n);
if (ir.next() != null) vb.add(Str.get(DOTS));
throw EBV_X.get(info, vb.value());
}
}
}
return it == null ? Bln.FALSE : it;
}
@Override
public Iter iter(final QueryContext qc) throws QueryException {
final Iter ir = exprs[0].iter(qc);
final long len = ir.size();
if (len == 0) throw ONEORMORE.get(info);
if (len > 0) return ir;
return new Iter() {
private boolean first = true;
@Override
public Item next() throws QueryException {
final Item it = ir.next();
if (first) {
if (it == null) throw ONEORMORE.get(info);
first = false;
}
return it;
}
};
}
/**
* Returns the next token of the specified iterator or {@code null}.
*
* @param iter iterator to be checked
* @return item
* @throws QueryException query exception
*/
private byte[] nextToken(final Iter iter) throws QueryException {
final Item it = iter.next();
return it == null ? null : toToken(it);
}
/**
* 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);
}