@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();
}
/**
* Returns the entries of an archive.
*
* @param ctx query context
* @return entries
* @throws QueryException query exception
*/
private Iter entries(final QueryContext ctx) throws QueryException {
final B64 archive = (B64) checkType(checkItem(expr[0], ctx), AtomType.B64);
final ValueBuilder vb = new ValueBuilder();
final ArchiveIn in = ArchiveIn.get(archive.input(info), info);
try {
while (in.more()) {
final ZipEntry ze = in.entry();
if (ze.isDirectory()) continue;
final FElem e = new FElem(Q_ENTRY, NS);
long s = ze.getSize();
if (s != -1) e.add(Q_SIZE, token(s));
s = ze.getTime();
if (s != -1) e.add(Q_LAST_MOD, new Dtm(s, info).string(info));
s = ze.getCompressedSize();
if (s != -1) e.add(Q_COMP_SIZE, token(s));
e.add(ze.getName());
vb.add(e);
}
return vb;
} catch (final IOException ex) {
Util.debug(ex);
throw ARCH_FAIL.thrw(info, ex);
} finally {
in.close();
}
}
/**
* Binds the specified parameter to a variable.
*
* @param rxp parameter
* @param args argument array
* @param values values to be bound; the parameter's default value is assigned if the argument is
* {@code null} or empty
* @throws QueryException query exception
*/
private void bind(final RestXqParam rxp, final Expr[] args, final String... values)
throws QueryException {
final Value val;
if (values == null || values.length == 0) {
val = rxp.value;
} else {
final ValueBuilder vb = new ValueBuilder();
for (final String s : values) vb.add(new Atm(s));
val = vb.value();
}
bind(rxp.name, args, val);
}
/**
* 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());
}
/**
* Extracts binary entries.
*
* @param ctx query context
* @return binary entry
* @throws QueryException query exception
*/
private ValueBuilder extractBinary(final QueryContext ctx) throws QueryException {
final ValueBuilder vb = new ValueBuilder();
for (final byte[] b : extract(ctx)) vb.add(new B64(b));
return vb;
}
/**
* Extracts text entries.
*
* @param ctx query context
* @return text entry
* @throws QueryException query exception
*/
private ValueBuilder extractText(final QueryContext ctx) throws QueryException {
final String enc = encoding(2, ARCH_ENCODING, ctx);
final ValueBuilder vb = new ValueBuilder();
for (final byte[] b : extract(ctx)) vb.add(Str.get(encode(b, enc)));
return vb;
}
