/**
* Checks if the predicates are successful for the specified item.
*
* @param it item to be checked
* @param qc query context
* @return result of check
* @throws QueryException query exception
*/
protected final boolean preds(final Item it, final QueryContext qc) throws QueryException {
if (preds.length == 0) return true;
// set context value and position
final Value cv = qc.value;
try {
if (qc.scoring) {
double s = 0;
for (final Expr p : preds) {
qc.value = it;
final Item i = p.test(qc, info);
if (i == null) return false;
s += i.score();
}
it.score(Scoring.avg(s, preds.length));
} else {
for (final Expr p : preds) {
qc.value = it;
if (p.test(qc, info) == null) return false;
}
}
return true;
} finally {
qc.value = cv;
}
}
@Override
public final Expr inline(final QueryContext ctx, final VarScope scp, final Var v, final Expr e)
throws QueryException {
final Value oldVal = ctx.value;
try {
ctx.value = root(ctx);
final Expr rt = root == null ? null : root.inline(ctx, scp, v, e);
if (rt != null) {
setRoot(ctx, rt);
ctx.value = oldVal;
ctx.value = root(ctx);
}
boolean change = rt != null;
for (int i = 0; i < steps.length; i++) {
final Expr nw = steps[i].inline(ctx, scp, v, e);
if (nw != null) {
steps[i] = nw;
change = true;
}
}
return change ? optimize(ctx, scp) : null;
} finally {
ctx.value = oldVal;
}
}
@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 final Expr compile(final QueryContext qc, final VarScope scp) throws QueryException {
if (root != null) root = root.compile(qc, scp);
// no steps
if (steps.length == 0) return root == null ? new Context(info) : root;
final Value init = qc.value, cv = initial(qc);
final boolean doc = cv != null && cv.type == NodeType.DOC;
qc.value = cv;
try {
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
Expr e = steps[s];
// axis step: if input is a document, its type is temporarily generalized
final boolean as = e instanceof Step;
if (as && s == 0 && doc) cv.type = NodeType.NOD;
e = e.compile(qc, scp);
if (e.isEmpty()) return optPre(qc);
steps[s] = e;
// no axis step: invalidate context value
if (!as) qc.value = null;
}
} finally {
if (doc) cv.type = NodeType.DOC;
qc.value = init;
}
// optimize path
return optimize(qc, scp);
}
/**
* Converts descendant to child steps.
*
* @param qc query context
* @param rt root value
* @return original or new expression
*/
private Expr children(final QueryContext qc, final Value rt) {
// skip if index does not exist or is out-dated, or if several namespaces occur in the input
final Data data = rt.data();
if (data == null || !data.meta.uptodate || data.nspaces.globalNS() == null) return this;
Path path = this;
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
// don't allow predicates in preceding location steps
final Step prev = s > 0 ? axisStep(s - 1) : null;
if (prev != null && prev.preds.length != 0) break;
// ignore axes other than descendant, or numeric predicates
final Step curr = axisStep(s);
if (curr == null || curr.axis != DESC || curr.has(Flag.FCS)) continue;
// check if child steps can be retrieved for current step
ArrayList<PathNode> nodes = pathNodes(data, s);
if (nodes == null) continue;
// cache child steps
final ArrayList<QNm> qnm = new ArrayList<>();
while (nodes.get(0).parent != null) {
QNm nm = new QNm(data.elemNames.key(nodes.get(0).name));
// skip children with prefixes
if (nm.hasPrefix()) return this;
for (final PathNode p : nodes) {
if (nodes.get(0).name != p.name) nm = null;
}
qnm.add(nm);
nodes = PathSummary.parent(nodes);
}
qc.compInfo(OPTCHILD, steps[s]);
// build new steps
int ts = qnm.size();
final Expr[] stps = new Expr[ts + sl - s - 1];
for (int t = 0; t < ts; t++) {
final Expr[] preds = t == ts - 1 ? ((Preds) steps[s]).preds : new Expr[0];
final QNm nm = qnm.get(ts - t - 1);
final NameTest nt =
nm == null ? new NameTest(false) : new NameTest(nm, Kind.NAME, false, null);
stps[t] = Step.get(info, CHILD, nt, preds);
}
while (++s < sl) stps[ts++] = steps[s];
path = get(info, root, stps);
break;
}
// check if all steps yield results; if not, return empty sequence
final ArrayList<PathNode> nodes = pathNodes(qc);
if (nodes != null && nodes.isEmpty()) {
qc.compInfo(OPTPATH, path);
return Empty.SEQ;
}
return path;
}
@Override
public Expr optimize(final QueryContext qc, final VarScope scp) throws QueryException {
// number of predicates may change in loop
for (int p = 0; p < preds.length; p++) {
final Expr pred = preds[p];
if (pred instanceof CmpG || pred instanceof CmpV) {
final Cmp cmp = (Cmp) pred;
if (cmp.exprs[0].isFunction(Function.POSITION)) {
final Expr e2 = cmp.exprs[1];
final SeqType st2 = e2.seqType();
// position() = last() -> last()
// position() = $n (numeric) -> $n
if (e2.isFunction(Function.LAST) || st2.one() && st2.type.isNumber()) {
if (cmp instanceof CmpG && ((CmpG) cmp).op == OpG.EQ
|| cmp instanceof CmpV && ((CmpV) cmp).op == OpV.EQ) {
qc.compInfo(OPTWRITE, pred);
preds[p] = e2;
}
}
}
} else if (pred instanceof And) {
if (!pred.has(Flag.FCS)) {
// replace AND expression with predicates (don't swap position tests)
qc.compInfo(OPTPRED, pred);
final Expr[] and = ((Arr) pred).exprs;
final int m = and.length - 1;
final ExprList el = new ExprList(preds.length + m);
for (final Expr e : Arrays.asList(preds).subList(0, p)) el.add(e);
for (final Expr a : and) {
// wrap test with boolean() if the result is numeric
el.add(Function.BOOLEAN.get(null, info, a).optimizeEbv(qc, scp));
}
for (final Expr e : Arrays.asList(preds).subList(p + 1, preds.length)) el.add(e);
preds = el.finish();
}
} else if (pred instanceof ANum) {
final ANum it = (ANum) pred;
final long i = it.itr();
if (i == it.dbl()) {
preds[p] = Pos.get(i, info);
} else {
qc.compInfo(OPTREMOVE, this, pred);
return Empty.SEQ;
}
} else if (pred.isValue()) {
if (pred.ebv(qc, info).bool(info)) {
qc.compInfo(OPTREMOVE, this, pred);
preds = Array.delete(preds, p--);
} else {
// handle statically known predicates
qc.compInfo(OPTREMOVE, this, pred);
return Empty.SEQ;
}
}
}
return this;
}
@Override
public final Expr compile(final QueryContext ctx, final VarScope scp) throws QueryException {
if (root != null) setRoot(ctx, root.compile(ctx, scp));
final Value v = ctx.value;
try {
ctx.value = root(ctx);
return compilePath(ctx, scp);
} finally {
ctx.value = v;
}
}
@Override
public Expr compile(final QueryContext qc, final VarScope scp) throws QueryException {
final Value init = qc.value;
// never compile predicates with empty sequence as context value (#1016)
if (init != null && init.isEmpty()) qc.value = null;
try {
final int pl = preds.length;
for (int p = 0; p < pl; ++p) preds[p] = preds[p].compile(qc, scp).optimizeEbv(qc, scp);
return this;
} finally {
qc.value = init;
}
}
@Override
Value[] evalArgs(final QueryContext ctx) throws QueryException {
final int al = expr.length - 1;
final Value[] args = new Value[al];
for (int a = 0; a < al; ++a) args[a] = ctx.value(expr[a]);
return args;
}
/**
* Optimizes descendant-or-self steps and static types.
*
* @param ctx query context
*/
void optSteps(final QueryContext ctx) {
boolean opt = false;
Expr[] st = steps;
for (int l = 1; l < st.length; ++l) {
if (!(st[l - 1] instanceof Step && st[l] instanceof Step)) continue;
final Step prev = (Step) st[l - 1];
final Step curr = (Step) st[l];
if (!prev.simple(DESCORSELF, false)) continue;
if (curr.axis == CHILD && !curr.has(Flag.FCS)) {
// descendant-or-self::node()/child::X -> descendant::X
final int sl = st.length;
final Expr[] tmp = new Expr[sl - 1];
System.arraycopy(st, 0, tmp, 0, l - 1);
System.arraycopy(st, l, tmp, l - 1, sl - l);
st = tmp;
curr.axis = DESC;
opt = true;
} else if (curr.axis == ATTR && !curr.has(Flag.FCS)) {
// descendant-or-self::node()/@X -> descendant-or-self::*/@X
prev.test = new NameTest(false);
opt = true;
}
}
if (opt) ctx.compInfo(OPTDESC);
// set atomic type for single attribute steps to speedup predicate tests
if (root == null && st.length == 1 && st[0] instanceof Step) {
final Step curr = (Step) st[0];
if (curr.axis == ATTR && curr.test.mode == Mode.STD) curr.type = SeqType.NOD_ZO;
}
steps = st;
}
/**
* Sets a new root expression and eliminates a superfluous context item.
*
* @param ctx query context
* @param rt root expression
*/
private void setRoot(final QueryContext ctx, final Expr rt) {
root = rt;
if (root instanceof Context) {
ctx.compInfo(OPTREMCTX);
root = null;
}
}
/**
* Extracts entries from the archive.
*
* @param ctx query context
* @return text entries
* @throws QueryException query exception
*/
private TokenList extract(final QueryContext ctx) throws QueryException {
final B64 archive = (B64) checkType(checkItem(expr[0], ctx), AtomType.B64);
TokenSet hs = null;
if (expr.length > 1) {
// filter result to specified entries
hs = new TokenSet();
final Iter names = ctx.iter(expr[1]);
for (Item en; (en = names.next()) != null; ) {
hs.add(checkElmStr(en).string(info));
}
}
final TokenList tl = new TokenList();
final ArchiveIn in = ArchiveIn.get(archive.input(info), info);
try {
while (in.more()) {
final ZipEntry ze = in.entry();
if (ze.isDirectory()) continue;
if (hs == null || hs.delete(token(ze.getName())) != 0) tl.add(in.read());
}
} catch (final IOException ex) {
Util.debug(ex);
ARCH_FAIL.thrw(info, ex);
} finally {
in.close();
}
return tl;
}
/**
* Returns a serializer for the given output stream. Optional output declarations within the query
* will be included in the serializer instance.
*
* @param os output stream
* @return serializer instance
* @throws IOException query exception
* @throws QueryException query exception
*/
public Serializer getSerializer(final OutputStream os) throws IOException, QueryException {
compile();
try {
return Serializer.get(os, qc.serParams());
} catch (final QueryIOException ex) {
throw ex.getCause();
}
}
@Override
public Value value(final QueryContext qc) throws QueryException {
if (seqType().zeroOrOne()) {
final Value v = item(qc, info);
return v == null ? Empty.SEQ : v;
}
return qc.iter(this).value();
}
/**
* Parses the query.
*
* @throws QueryException query exception
*/
public void parse() throws QueryException {
if (parsed) return;
try {
qc.parseMain(query, null, sc);
} finally {
parsed = true;
updating = qc.updating;
}
}
/**
* Returns all tokens of the query.
*
* @param qc query context
* @return token list
* @throws QueryException query exception
*/
private TokenList tokens(final QueryContext qc) throws QueryException {
final TokenList tl = new TokenList();
final Iter ir = qc.iter(query);
for (byte[] qu; (qu = nextToken(ir)) != null; ) {
// skip empty tokens if not all results are needed
if (qu.length != 0 || mode == FTMode.ALL || mode == FTMode.ALL_WORDS) tl.add(qu);
}
return tl;
}
@Override
public Iter iter(final QueryContext qc) throws QueryException {
final Value seq = qc.value(ts);
for (final TypeCase tc : cases) {
final Iter iter = tc.iter(qc, seq);
if (iter != null) return iter;
}
// will never happen
throw Util.notExpected();
}
@Override
public Value value(final QueryContext qc) throws QueryException {
// don't catch errors from error handlers
try {
return qc.value(expr);
} catch (final QueryException ex) {
if (!ex.isCatchable()) throw ex;
for (final Catch c : catches) if (c.matches(ex)) return c.value(qc, ex);
throw ex;
}
}
@Override
public Expr compile(final QueryContext ctx) throws QueryException {
super.compile(ctx);
if (expr[0].isEmpty()) return optPre(null, ctx);
for (int e = 1; e < expr.length; ++e) {
if (expr[e].isEmpty()) {
ctx.compInfo(OPTREMOVE, description(), expr[e]);
expr = Array.delete(expr, e--);
}
}
// results must always be sorted
return expr.length == 1 && iterable ? expr[0] : this;
}
@Override
public Expr optimize(final QueryContext ctx, final VarScope scp) throws QueryException {
if (root instanceof Context) {
ctx.compInfo(OPTREMCTX);
root = null;
}
for (final Expr e : steps) {
// check for empty steps
if (e.isEmpty()) return optPre(null, ctx);
}
return this;
}
@Override
public final Expr compile(final QueryContext ctx, final VarScope scp) throws QueryException {
// invalidate current context value (will be overwritten by filter)
final Value cv = ctx.value;
try {
root = root.compile(ctx, scp);
// return empty root
if (root.isEmpty()) return optPre(null, ctx);
// convert filters without numeric predicates to axis paths
if (root instanceof AxisPath && !super.has(Flag.FCS))
return ((AxisPath) root.copy(ctx, scp)).addPreds(ctx, scp, preds).compile(ctx, scp);
// optimize filter expressions
ctx.value = null;
final Expr e = super.compile(ctx, scp);
if (e != this) return e;
// no predicates.. return root; otherwise, do some advanced compilations
return preds.length == 0 ? root : opt(ctx);
} finally {
ctx.value = cv;
}
}
/**
* Creates a new archive.
*
* @param ctx query context
* @return archive
* @throws QueryException query exception
*/
private B64 create(final QueryContext ctx) throws QueryException {
final Iter entr = ctx.iter(expr[0]);
final Iter cont = ctx.iter(expr[1]);
final Item opt = expr.length > 2 ? expr[2].item(ctx, info) : null;
final TokenMap map = new FuncParams(Q_OPTIONS, info).parse(opt);
final byte[] f = map.get(FORMAT);
final String format = f != null ? string(lc(f)) : "zip";
final ArchiveOut out = ArchiveOut.get(format, info);
// check algorithm
final byte[] alg = map.get(ALGORITHM);
int level = ZipEntry.DEFLATED;
if (alg != null) {
if (format.equals("zip") && !eq(alg, STORED, DEFLATE)
|| format.equals("gzip") && !eq(alg, DEFLATE)) {
ARCH_SUPP.thrw(info, ALGORITHM, alg);
}
if (eq(alg, STORED)) level = ZipEntry.STORED;
else if (eq(alg, DEFLATE)) level = ZipEntry.DEFLATED;
}
out.level(level);
try {
int e = 0;
int c = 0;
Item en, cn;
while (true) {
en = entr.next();
cn = cont.next();
if (en == null || cn == null) break;
if (out instanceof GZIPOut && c > 0)
ARCH_ONE.thrw(info, format.toUpperCase(Locale.ENGLISH));
add(checkElmStr(en), cn, out, level);
e++;
c++;
}
// count remaining entries
if (cn != null) do c++; while (cont.next() != null);
if (en != null) do e++; while (entr.next() != null);
if (e != c) throw ARCH_DIFF.thrw(info, e, c);
} catch (final IOException ex) {
Util.debug(ex);
throw ARCH_FAIL.thrw(info, ex);
} finally {
out.close();
}
return new B64(out.toArray());
}
/**
* Merges expensive descendant-or-self::node() steps.
*
* @param qc query context
* @return original or new expression
*/
private Expr mergeSteps(final QueryContext qc) {
boolean opt = false;
final int sl = steps.length;
final ExprList stps = new ExprList(sl);
for (int s = 0; s < sl; s++) {
final Expr step = steps[s];
// check for simple descendants-or-self step with succeeding step
if (s < sl - 1 && step instanceof Step) {
final Step curr = (Step) step;
if (curr.simple(DESCORSELF, false)) {
// check succeeding step
final Expr next = steps[s + 1];
// descendant-or-self::node()/child::X -> descendant::X
if (simpleChild(next)) {
((Step) next).axis = DESC;
opt = true;
continue;
}
// descendant-or-self::node()/(X, Y) -> (descendant::X | descendant::Y)
Expr e = mergeList(next);
if (e != null) {
steps[s + 1] = e;
opt = true;
continue;
}
// //(X, Y)[text()] -> (/descendant::X | /descendant::Y)[text()]
if (next instanceof Filter && !next.has(Flag.FCS)) {
final Filter f = (Filter) next;
e = mergeList(f.root);
if (e != null) {
f.root = e;
opt = true;
continue;
}
}
}
}
stps.add(step);
}
if (opt) {
qc.compInfo(OPTDESC);
return get(info, root, stps.finish());
}
return this;
}
/**
* Updates an archive.
*
* @param ctx query context
* @return updated archive
* @throws QueryException query exception
*/
private B64 update(final QueryContext ctx) throws QueryException {
final B64 archive = (B64) checkType(checkItem(expr[0], ctx), AtomType.B64);
// entries to be updated
final TokenObjMap<Item[]> hm = new TokenObjMap<Item[]>();
final Iter entr = ctx.iter(expr[1]);
final Iter cont = ctx.iter(expr[2]);
int e = 0;
int c = 0;
Item en, cn;
while (true) {
en = entr.next();
cn = cont.next();
if (en == null || cn == null) break;
hm.add(checkElmStr(en).string(info), new Item[] {en, cn});
e++;
c++;
}
// count remaining entries
if (cn != null) do c++; while (cont.next() != null);
if (en != null) do e++; while (entr.next() != null);
if (e != c) ARCH_DIFF.thrw(info, e, c);
final ArchiveIn in = ArchiveIn.get(archive.input(info), info);
final ArchiveOut out = ArchiveOut.get(in.format(), info);
try {
if (in instanceof GZIPIn) ARCH_MODIFY.thrw(info, in.format().toUpperCase(Locale.ENGLISH));
// delete entries to be updated
while (in.more()) if (!hm.contains(token(in.entry().getName()))) out.write(in);
// add new and updated entries
for (final byte[] h : hm) {
if (h == null) continue;
final Item[] it = hm.get(h);
add(it[0], it[1], out, ZipEntry.DEFLATED);
}
} catch (final IOException ex) {
Util.debug(ex);
ARCH_FAIL.thrw(info, ex);
} finally {
in.close();
out.close();
}
return new B64(out.toArray());
}
@Override
public Expr optimize(final QueryContext qc, final VarScope scp) throws QueryException {
super.optimize(qc, scp);
final ExprList el = new ExprList(exprs.length);
for (final Expr ex : exprs) {
if (ex.isEmpty()) {
// remove empty operands (return empty sequence if first value is empty)
if (el.isEmpty()) return optPre(qc);
qc.compInfo(OPTREMOVE_X_X, this, ex);
} else {
el.add(ex);
}
}
// ensure that results are always sorted
if (el.size() == 1 && iterable) return el.get(0);
// replace expressions with optimized list
exprs = el.finish();
return this;
}
/**
* Deletes files from an archive.
*
* @param ctx query context
* @return updated archive
* @throws QueryException query exception
*/
private B64 delete(final QueryContext ctx) throws QueryException {
final B64 archive = (B64) checkType(checkItem(expr[0], ctx), AtomType.B64);
// entries to be deleted
final TokenObjMap<Item[]> hm = new TokenObjMap<Item[]>();
final Iter names = ctx.iter(expr[1]);
for (Item en; (en = names.next()) != null; ) {
hm.add(checkElmStr(en).string(info), null);
}
final ArchiveIn in = ArchiveIn.get(archive.input(info), info);
final ArchiveOut out = ArchiveOut.get(in.format(), info);
try {
if (in instanceof GZIPIn) ARCH_MODIFY.thrw(info, in.format().toUpperCase(Locale.ENGLISH));
while (in.more()) if (!hm.contains(token(in.entry().getName()))) out.write(in);
} catch (final IOException ex) {
Util.debug(ex);
ARCH_FAIL.thrw(info, ex);
} finally {
in.close();
out.close();
}
return new B64(out.toArray());
}
/**
* Returns an equivalent expression which accesses an index. If the expression cannot be
* rewritten, the original expression is returned.
*
* <p>The following types of queries can be rewritten (in the examples, the equality comparison is
* used, which will be rewritten to {@link ValueAccess} instances):
*
* <pre>
* 1. A[text() = '...'] -> IA('...')
* 2. A[. = '...'] -> IA('...', A)
* 3. text()[. = '...'] -> IA('...')
* 4. A[B = '...'] -> IA('...', B)/parent::A
* 1. A[B/text() = '...'] -> IA('...')/parent::B/parent::A
* 2. A[B/C = '...'] -> IA('...', C)/parent::B/parent::A
* 7. A[@a = '...'] -> IA('...', @a)/parent::A
* 8. @a[. = '...'] -> IA('...', @a)</pre>
*
* Queries of type 1, 3, 5 will not yield any results if the string to be compared is empty.
*
* @param qc query context
* @param rt root value
* @return original or new expression
* @throws QueryException query exception
*/
private Expr index(final QueryContext qc, final Value rt) throws QueryException {
// only rewrite paths with data reference
final Data data = rt.data();
if (data == null) return this;
// cache index access costs
IndexInfo index = null;
// cheapest predicate and step
int iPred = 0, iStep = 0;
// check if path can be converted to an index access
final int sl = steps.length;
for (int s = 0; s < sl; s++) {
// only accept descendant steps without positional predicates
final Step step = axisStep(s);
if (step == null || !step.axis.down || step.has(Flag.FCS)) break;
// check if path is iterable (i.e., will be duplicate-free)
final boolean iter = pathNodes(data, s) != null;
final IndexContext ictx = new IndexContext(data, iter);
// choose cheapest index access
final int pl = step.preds.length;
for (int p = 0; p < pl; p++) {
final IndexInfo ii = new IndexInfo(ictx, qc, step);
if (!step.preds[p].indexAccessible(ii)) continue;
if (ii.costs == 0) {
// no results...
qc.compInfo(OPTNOINDEX, this);
return Empty.SEQ;
}
if (index == null || index.costs > ii.costs) {
index = ii;
iPred = p;
iStep = s;
}
}
}
// skip rewriting if no index access is possible, or if it is too expensive
if (index == null || index.costs > data.meta.size) return this;
// rewrite for index access
qc.compInfo(index.info);
// replace expressions for index access
final Step indexStep = index.step;
// collect remaining predicates
final int pl = indexStep.preds.length;
final ExprList newPreds = new ExprList(pl - 1);
for (int p = 0; p < pl; p++) {
if (p != iPred) newPreds.add(indexStep.preds[p]);
}
// invert steps that occur before index step and add them as predicate
final Test test = InvDocTest.get(rt);
final ExprList invSteps = new ExprList();
if (test != Test.DOC || !data.meta.uptodate || predSteps(data, iStep)) {
for (int s = iStep; s >= 0; s--) {
final Axis ax = axisStep(s).axis.invert();
if (s == 0) {
// add document test for collections and axes other than ancestors
if (test != Test.DOC || ax != Axis.ANC && ax != Axis.ANCORSELF)
invSteps.add(Step.get(info, ax, test));
} else {
final Step prev = axisStep(s - 1);
invSteps.add(Step.get(info, ax, prev.test, prev.preds));
}
}
}
if (!invSteps.isEmpty()) newPreds.add(get(info, null, invSteps.finish()));
// create resulting expression
final ExprList resultSteps = new ExprList();
final Expr resultRoot;
if (index.expr instanceof Path) {
final Path p = (Path) index.expr;
resultRoot = p.root;
resultSteps.add(p.steps);
} else {
resultRoot = index.expr;
}
if (!newPreds.isEmpty()) {
int ls = resultSteps.size() - 1;
Step step;
if (ls < 0 || !(resultSteps.get(ls) instanceof Step)) {
// add at least one self axis step
step = Step.get(info, Axis.SELF, Test.NOD);
ls++;
} else {
step = (Step) resultSteps.get(ls);
}
// add remaining predicates to last step
resultSteps.set(ls, step.addPreds(newPreds.finish()));
}
// add remaining steps
for (int s = iStep + 1; s < sl; s++) resultSteps.add(steps[s]);
return get(info, resultRoot, resultSteps.finish());
}
/**
* Adds an optimization info for pre-evaluating the specified expression.
*
* @param ex optimized expression
* @param qc query context
* @return optimized expression
*/
protected final Expr optPre(final Expr ex, final QueryContext qc) {
if (ex != this) qc.compInfo(OPTPRE_X, this);
return ex == null ? Empty.SEQ : ex;
}
/**
* Evaluates the specified function and creates a response.
*
* @throws Exception exception (including unexpected ones)
*/
void create() throws Exception {
// bind variables
final StaticFunc sf = function.function;
final Expr[] args = new Expr[sf.args.length];
function.bind(http, args, error);
// wrap function with a function call
final MainModule mm = new MainModule(sf, args);
// assign main module and http context and register process
query.mainModule(mm);
query.http(http);
query.context.register(query);
String redirect = null, forward = null;
RestXqRespBuilder resp = null;
try {
// compile and evaluate query
query.compile();
final Iter iter = query.iter();
Item item = iter.next();
// handle response element
if (item != null && item instanceof ANode) {
final ANode node = (ANode) item;
// send redirect to browser
if (REST_REDIRECT.eq(node)) {
final ANode ch = node.children().next();
if (ch == null || ch.type != NodeType.TXT) throw function.error(NO_VALUE, node.name());
redirect = string(ch.string()).trim();
return;
}
// server-side forwarding
if (REST_FORWARD.eq(node)) {
final ANode ch = node.children().next();
if (ch == null || ch.type != NodeType.TXT) throw function.error(NO_VALUE, node.name());
forward = string(ch.string()).trim();
return;
}
if (REST_RESPONSE.eq(node)) {
resp = new RestXqRespBuilder();
resp.build(node, function, iter, http);
return;
}
}
// HEAD method must return a single response element
if (function.methods.size() == 1 && function.methods.contains(HTTPMethod.HEAD.name()))
throw function.error(HEAD_METHOD);
// serialize result
final SerializerOptions sp = function.output;
http.sopts(sp);
http.initResponse();
final Serializer ser = Serializer.get(http.res.getOutputStream(), sp);
for (; item != null; item = iter.next()) ser.serialize(item);
ser.close();
} finally {
query.close();
query.context.unregister(query);
if (redirect != null) {
http.res.sendRedirect(redirect);
} else if (forward != null) {
http.req.getRequestDispatcher(forward).forward(http.req, http.res);
} else if (resp != null) {
if (resp.status != 0) http.status(resp.status, resp.message, resp.error);
http.res.getOutputStream().write(resp.cache.toArray());
}
}
}
/**
* Returns a result value.
*
* @return result value
* @throws QueryException query exception
*/
public Value value() throws QueryException {
parse();
return qc.iter().value();
}
