@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);
}
@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 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
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;
}
@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 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;
}
}