/**
* Returns all summary path nodes for the specified location step or {@code null} if nodes cannot
* be retrieved or are found on different levels.
*
* @param data data reference
* @param last last step to be checked
* @return path nodes
*/
private ArrayList<PathNode> pathNodes(final Data data, final int last) {
// skip request if no path index exists or might be out-of-date
if (!data.meta.uptodate) return null;
ArrayList<PathNode> nodes = data.paths.root();
for (int s = 0; s <= last; s++) {
// only follow axis steps
final Step curr = axisStep(s);
if (curr == null) return null;
final boolean desc = curr.axis == DESC;
if (!desc && curr.axis != CHILD || curr.test.kind != Kind.NAME) return null;
final int name = data.elemNames.id(curr.test.name.local());
final ArrayList<PathNode> tmp = new ArrayList<>();
for (final PathNode node : PathSummary.desc(nodes, desc)) {
if (node.kind == Data.ELEM && name == node.name) {
// skip test if an element name occurs on different levels
if (!tmp.isEmpty() && tmp.get(0).level() != node.level()) return null;
tmp.add(node);
}
}
if (tmp.isEmpty()) return null;
nodes = tmp;
}
return nodes;
}
/**
* Algorithm of Tarjan for computing the strongly connected components of a graph.
*
* @param v current node
* @throws QueryException if a variable directly calls itself
*/
private void tarjan(final int v) throws QueryException {
final int ixv = 2 * v, llv = ixv + 1, idx = next++;
while (list.size() <= llv) list.add(-1);
list.set(ixv, idx);
list.set(llv, idx);
stack.push(v);
for (final int w : adjacentTo(v)) {
final int ixw = 2 * w, llw = ixw + 1;
if (list.size() <= ixw || list.get(ixw) < 0) {
// Successor w has not yet been visited; recurse on it
tarjan(w);
list.set(llv, Math.min(list.get(llv), list.get(llw)));
} else if (stack.contains(w)) {
// Successor w is in stack S and hence in the current SCC
list.set(llv, Math.min(list.get(llv), list.get(ixw)));
}
}
// If v is a root node, pop the stack and generate an SCC
if (list.get(llv) == list.get(ixv)) {
int w;
Scope[] out = null;
do {
w = stack.pop();
final Scope scp = scopes.get(w);
out = out == null ? new Scope[] {scp} : Array.add(out, scp);
} while (w != v);
result.add(out);
}
}
/**
* Performs the test-uris function.
*
* @param ctx query context
* @return resulting value
* @throws QueryException query exception
*/
private Item testUris(final QueryContext ctx) throws QueryException {
checkCreate(ctx);
final ArrayList<IO> inputs = new ArrayList<>();
final Iter ir = ctx.iter(expr[0]);
for (Item it; (it = ir.next()) != null; ) inputs.add(checkPath(it, ctx));
return new Suite(ctx, info).test(inputs);
}
/**
* Returns all summary path nodes for the specified location step or {@code null} if nodes cannot
* be retrieved or are found on different levels.
*
* @param data data reference
* @param l last step to be checked
* @return path nodes
*/
ArrayList<PathNode> pathNodes(final Data data, final int l) {
// skip request if no path index exists or might be out-of-date
if (!data.meta.uptodate) return null;
ArrayList<PathNode> in = data.paths.root();
for (int s = 0; s <= l; ++s) {
final Step curr = axisStep(s);
if (curr == null) return null;
final boolean desc = curr.axis == DESC;
if (!desc && curr.axis != CHILD || curr.test.mode != Mode.LN) return null;
final int name = data.tagindex.id(curr.test.name.local());
final ArrayList<PathNode> al = new ArrayList<>();
for (final PathNode pn : PathSummary.desc(in, desc)) {
if (pn.kind == Data.ELEM && name == pn.name) {
// skip test if a tag is found on different levels
if (!al.isEmpty() && al.get(0).level() != pn.level()) return null;
al.add(pn);
}
}
if (al.isEmpty()) return null;
in = al;
}
return in;
}
/**
* Returns the indices of all scopes called by the given one.
*
* @param node source node index
* @return destination node indices
* @throws QueryException if a variable directly calls itself
*/
private int[] adjacentTo(final int node) throws QueryException {
int[] adj = adjacent.get(node);
if (adj == null) {
adj = neighbors(scopes.get(node));
adjacent.set(node, adj);
}
return adj;
}
/**
* 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;
}
/**
* Gets the ID of the given scope.
*
* @param scp scope
* @return id if existing, {@code null} otherwise
*/
private int id(final Scope scp) {
if (ids != null) {
final Integer id = ids.get(scp);
return id == null ? -1 : id;
}
final int ss = scopes.size();
for (int s = 0; s < ss; s++) if (scopes.get(s) == scp) return s;
return -1;
}
/**
* Adds a new scope and returns its ID.
*
* @param scp scope to add
* @return the scope's ID
*/
private int add(final Scope scp) {
final int id = scopes.size();
if (id == MAP_THRESHOLD) {
ids = new IdentityHashMap<>();
for (final Scope s : scopes) ids.put(s, ids.size());
}
scopes.add(scp);
adjacent.add(null);
if (ids != null) ids.put(scp, id);
return id;
}
/**
* Performs the test function.
*
* @param ctx query context
* @return resulting value
* @throws QueryException query exception
*/
private Item test(final QueryContext ctx) throws QueryException {
final Unit unit = new Unit(ctx, info);
if (expr.length == 0) return unit.test(sc);
final ArrayList<StaticFunc> funcs = new ArrayList<>();
final Iter ir = ctx.iter(expr[0]);
for (Item it; (it = ir.next()) != null; ) {
final FItem fi = checkFunc(it, ctx);
if (fi.funcName() != null) {
final StaticFunc sf = ctx.funcs.get(fi.funcName(), fi.arity(), null, true);
if (sf != null) funcs.add(sf);
}
}
return unit.test(sc, funcs);
}
/**
* Checks if steps before index step need to be inverted and traversed.
*
* @param data data reference
* @param iStep index step
* @return result of check
*/
private boolean predSteps(final Data data, final int iStep) {
for (int s = iStep; s >= 0; s--) {
final Step step = axisStep(s);
// ensure that the index step does not use wildcard
if (step.test.kind == Kind.WILDCARD && s != iStep) continue;
// consider child steps with name test and without predicates
if (step.test.kind != Kind.NAME
|| step.axis != Axis.CHILD
|| s != iStep && step.preds.length > 0) return true;
// support only unique paths with nodes on the correct level
final ArrayList<PathNode> pn = data.paths.desc(step.test.name.local());
if (pn.size() != 1 || pn.get(0).level() != s + 1) return true;
}
return false;
}
/**
* Returns the strongly connected components of the dependency graph.
*
* @param p ID of the starting point
* @return the components
* @throws QueryException if a variable directly calls itself
*/
private Iterable<Scope[]> components(final int p) throws QueryException {
result.clear();
tarjan(p);
return result;
}
/**
* Binds the annotated variables.
*
* @param http http context
* @param arg argument array
* @throws QueryException query exception
* @throws IOException I/O exception
*/
void bind(final HTTPContext http, final Expr[] arg) throws QueryException, IOException {
// bind variables from segments
for (int s = 0; s < path.size; s++) {
final Matcher m = TEMPLATE.matcher(path.segment[s]);
if (!m.find()) continue;
final QNm qnm = new QNm(token(m.group(1)), context);
bind(qnm, arg, new Atm(http.segment(s)));
}
// cache request body
final String ct = http.contentType();
IOContent body = null;
if (requestBody != null) {
body = cache(http, null);
try {
// bind request body in the correct format
body.name(http.method + IO.XMLSUFFIX);
bind(requestBody, arg, Parser.item(body, context.context.prop, ct));
} catch (final IOException ex) {
error(INPUT_CONV, ex);
}
}
// bind query parameters
final Map<String, String[]> params = http.params();
for (final RestXqParam rxp : queryParams) bind(rxp, arg, params.get(rxp.key));
// bind form parameters
if (!formParams.isEmpty()) {
if (MimeTypes.APP_FORM.equals(ct)) {
// convert parameters encoded in a form
body = cache(http, body);
addParams(body.toString(), params);
}
for (final RestXqParam rxp : formParams) bind(rxp, arg, params.get(rxp.key));
}
// bind header parameters
for (final RestXqParam rxp : headerParams) {
final StringList sl = new StringList();
final Enumeration<?> en = http.req.getHeaders(rxp.key);
while (en.hasMoreElements()) {
for (final String s : en.nextElement().toString().split(", *")) sl.add(s);
}
bind(rxp, arg, sl.toArray());
}
// bind cookie parameters
final Cookie[] ck = http.req.getCookies();
for (final RestXqParam rxp : cookieParams) {
String v = null;
if (ck != null) {
for (final Cookie c : ck) {
if (rxp.key.equals(c.getName())) v = c.getValue();
}
}
if (v == null) bind(rxp, arg);
else bind(rxp, arg, v);
}
}
/**
* Checks a function for RESTFful annotations.
*
* @return {@code true} if module contains relevant annotations
* @throws QueryException query exception
*/
boolean analyze() throws QueryException {
// parse all annotations
final EnumSet<HTTPMethod> mth = EnumSet.noneOf(HTTPMethod.class);
final boolean[] declared = new boolean[function.args.length];
boolean found = false;
final int as = function.ann.size();
for (int a = 0; a < as; a++) {
final QNm name = function.ann.names[a];
final Value value = function.ann.values[a];
final byte[] local = name.local();
final byte[] uri = name.uri();
final boolean rexq = eq(uri, QueryText.RESTXQURI);
if (rexq) {
if (eq(PATH, local)) {
// annotation "path"
if (path != null) error(ANN_TWICE, "%", name.string());
path = new RestXqPath(toString(value, name));
for (final String s : path) {
if (s.trim().startsWith("{")) checkVariable(s, AtomType.AAT, declared);
}
} else if (eq(CONSUMES, local)) {
// annotation "consumes"
strings(value, name, consumes);
} else if (eq(PRODUCES, local)) {
// annotation "produces"
strings(value, name, produces);
} else if (eq(QUERY_PARAM, local)) {
// annotation "query-param"
queryParams.add(param(value, name, declared));
} else if (eq(FORM_PARAM, local)) {
// annotation "form-param"
formParams.add(param(value, name, declared));
} else if (eq(HEADER_PARAM, local)) {
// annotation "header-param"
headerParams.add(param(value, name, declared));
} else if (eq(COOKIE_PARAM, local)) {
// annotation "cookie-param"
cookieParams.add(param(value, name, declared));
} else {
// method annotations
final HTTPMethod m = HTTPMethod.get(string(local));
if (m == null) error(ANN_UNKNOWN, "%", name.string());
if (!value.isEmpty()) {
// remember post/put variable
if (requestBody != null) error(ANN_TWICE, "%", name.string());
if (m != POST && m != PUT) error(METHOD_VALUE, m);
requestBody = checkVariable(toString(value, name), declared);
}
if (mth.contains(m)) error(ANN_TWICE, "%", name.string());
mth.add(m);
}
} else if (eq(uri, QueryText.OUTPUTURI)) {
// serialization parameters
final String key = string(local);
final String val = toString(value, name);
if (output.get(key) == null) error(UNKNOWN_SER, key);
output.set(key, val);
}
found |= rexq;
}
if (!mth.isEmpty()) methods = mth;
if (found) {
if (path == null) error(ANN_MISSING, PATH);
for (int i = 0; i < declared.length; i++)
if (!declared[i]) error(VAR_UNDEFINED, function.args[i].name.string());
}
return found;
}
/**
* Converts descendant to child steps.
*
* @param ctx query context
* @param data data reference
* @return path
*/
Expr children(final QueryContext ctx, final Data data) {
// skip path check if no path index exists, or if it is out-of-date
if (!data.meta.uptodate || data.nspaces.globalNS() == null) return this;
Path path = this;
for (int s = 0; s < steps.length; ++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> pn = pathNodes(data, s);
if (pn == null) continue;
// cache child steps
final ArrayList<QNm> qnm = new ArrayList<>();
while (pn.get(0).par != null) {
QNm nm = new QNm(data.tagindex.key(pn.get(0).name));
// skip children with prefixes
if (nm.hasPrefix()) return this;
for (final PathNode p : pn) {
if (pn.get(0).name != p.name) nm = null;
}
qnm.add(nm);
pn = PathSummary.parent(pn);
}
ctx.compInfo(OPTCHILD, steps[s]);
// build new steps
int ts = qnm.size();
final Expr[] stps = new Expr[ts + steps.length - 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, Mode.LN, false, null);
stps[t] = Step.get(info, CHILD, nt, preds);
}
while (++s < steps.length) stps[ts++] = steps[s];
path = get(info, root, stps);
break;
}
// check if the all children in the path exist; don't test with namespaces
if (data.nspaces.size() == 0) {
LOOP:
for (int s = 0; s < path.steps.length; ++s) {
// only verify child steps; ignore namespaces
final Step st = path.axisStep(s);
if (st == null || st.axis != CHILD) break;
if (st.test.mode == Mode.ALL || st.test.mode == null) continue;
if (st.test.mode != Mode.LN) break;
// check if one of the addressed nodes is on the correct level
final int name = data.tagindex.id(st.test.name.local());
for (final PathNode pn : data.paths.desc(name, Data.ELEM)) {
if (pn.level() == s + 1) continue LOOP;
}
ctx.compInfo(OPTPATH, path);
return Empty.SEQ;
}
}
return path;
}