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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2022 Saxonica Limited
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.functions;
import net.sf.saxon.expr.*;
import net.sf.saxon.expr.parser.PathMap;
import net.sf.saxon.expr.parser.RetainedStaticContext;
import net.sf.saxon.expr.sort.LocalOrderComparer;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.NodeSetPattern;
import net.sf.saxon.pattern.Pattern;
import net.sf.saxon.trans.KeyDefinition;
import net.sf.saxon.trans.KeyDefinitionSet;
import net.sf.saxon.trans.KeyManager;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.iter.EmptyIterator;
import net.sf.saxon.tree.iter.SingletonIterator;
import net.sf.saxon.tree.util.Navigator;
import net.sf.saxon.type.Type;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.EmptySequence;
import java.util.ArrayList;
import java.util.List;
public class KeyFn extends SystemFunction implements StatefulSystemFunction {
private KeyDefinitionSet staticKeySet = null;
public KeyManager getKeyManager() {
return getRetainedStaticContext().getPackageData().getKeyManager();
}
public NamespaceResolver getNamespaceResolver() {
return getRetainedStaticContext();
}
/**
* Factory method to create an internal call on key() with a known key definition
*
* @param keySet the set of KeyDefinitions (always a single KeyDefinition)
* @param name the name allocated to the key (first argument of the function)
* @param value the value being searched for (second argument of the function)
* @param doc the document being searched (third argument)
* @return a call on the key() function
*/
public static Expression internalKeyCall(KeyManager keyManager, KeyDefinitionSet keySet,
String name, Expression value, Expression doc,
RetainedStaticContext rsc) {
KeyFn fn = (KeyFn) SystemFunction.makeFunction("key", rsc, 3);
assert fn != null;
fn.staticKeySet = keySet;
try {
fn.fixArguments(new StringLiteral(name), value, doc);
} catch (XPathException e) {
// ignore the failure
}
return fn.makeFunctionCall(new StringLiteral(name), value, doc);
}
/**
* Get the static properties of this expression (other than its type). The result is
* bit-signficant. These properties are used for optimizations. In general, if
* a property bit is set, it is true, but if it is unset, the value is unknown.
*
* @param arguments expressions supplied as arguments in the function call
*/
@Override
public int getSpecialProperties(Expression[] arguments) {
int prop = StaticProperty.ORDERED_NODESET |
StaticProperty.SINGLE_DOCUMENT_NODESET |
StaticProperty.NO_NODES_NEWLY_CREATED;
if ((getArity() == 2) ||
(arguments[2].getSpecialProperties() & StaticProperty.CONTEXT_DOCUMENT_NODESET) != 0) {
prop |= StaticProperty.CONTEXT_DOCUMENT_NODESET;
}
return prop;
}
@Override
public SystemFunction copy() {
KeyFn k2 = (KeyFn) SystemFunction.makeFunction(getFunctionName().getLocalPart(), getRetainedStaticContext(), getArity());
k2.staticKeySet = staticKeySet;
return k2;
}
/**
* Allow the function to create an optimized call based on the values of the actual arguments.
* This binds the key definition in the common case where the key name is defined statically
*
* @param arguments the supplied arguments to the function call. Note: modifying the contents
* of this array should not be attempted, it is likely to have no effect.
* @return either a function call on this function, or an expression that delivers
* the same result, or null indicating that no optimization has taken place
* @throws XPathException if an error is detected
*/
@Override
public Expression fixArguments(final Expression... arguments) throws XPathException {
if (arguments[0] instanceof StringLiteral && staticKeySet == null) {
KeyManager keyManager = getKeyManager();
String keyName = ((StringLiteral) arguments[0]).stringify();
staticKeySet = getKeyDefinitionSet(keyManager, keyName);
}
return null;
}
/**
* Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited
* by an expression in a source tree.
* The default implementation of this method assumes that an expression does no navigation other than
* the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the
* same context as the containing expression. The method must be overridden for any expression
* where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression,
* and RootExpression (because they perform navigation), and for the doc(), document(), and collection()
* functions because they create a new navigation root. Implementations also exist for PathExpression and
* FilterExpression because they have subexpressions that are evaluated in a different context from the
* calling expression.
*
* @param pathMap the PathMap to which the expression should be added
* @param pathMapNodeSet the PathMapNodeSet to which the paths embodied in this expression should be added
* @return the pathMapNodeSet representing the points in the source document that are both reachable by this
* expression, and that represent possible results of this expression. For an expression that does
* navigation, it represents the end of the arc in the path map that describes the navigation route. For other
* expressions, it is the same as the input pathMapNode.
*/
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) {
if (staticKeySet != null) {
PathMap.PathMapNodeSet result = new PathMap.PathMapNodeSet();
for (KeyDefinition kd : staticKeySet.getKeyDefinitions()) {
Pattern pat = kd.getMatch();
if (pat instanceof NodeSetPattern) {
Expression selector = ((NodeSetPattern) pat).getSelectionExpression();
PathMap.PathMapNodeSet selected = selector.addToPathMap(pathMap, pathMapNodeSet);
Expression use = kd.getUse();
PathMap.PathMapNodeSet used = use.addToPathMap(pathMap, selected);
result.addNodeSet(selected);
} else {
throw new IllegalStateException("Can't add key() call to pathmap");
}
}
return result;
} else {
throw new IllegalStateException("Can't add dynamic key() call to pathmap");
}
}
/**
* Evaluate the expression
*
* @param context the dynamic evaluation context
* @param arguments the values of the arguments, supplied as Sequences
* @return the result of the evaluation, in the form of a Sequence
* @throws net.sf.saxon.trans.XPathException if a dynamic error occurs during the evaluation of the expression
*/
@Override
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
NodeInfo origin;
if (arguments.length == 3) {
origin = (NodeInfo) getOrigin(context, arguments[2]);
} else {
origin = getContextRoot(context);
}
if (origin.getRoot().getNodeKind() != Type.DOCUMENT) {
throw new XPathException("In the key() function," +
" the node supplied in the third argument (or the context node if absent)" +
" must be in a tree whose root is a document node", "XTDE1270", context);
}
KeyDefinitionSet selectedKeySet = staticKeySet;
KeyManager keyManager = getKeyManager();
if (selectedKeySet == null) {
selectedKeySet = getKeyDefinitionSet(keyManager, arguments[0].head().getStringValue());
}
return search(keyManager, context, arguments[1], origin, selectedKeySet);
}
private static NodeInfo getContextRoot(XPathContext context) throws XPathException {
Item contextItem = context.getContextItem();
if (contextItem == null) {
throw new XPathException("Cannot call the key() function when there is no context item", "XTDE1270", context);
} else if (!(contextItem instanceof NodeInfo)) {
throw new XPathException("Cannot call the key() function when the context item is not a node", "XTDE1270", context);
}
return ((NodeInfo) contextItem).getRoot();
}
private static Item getOrigin(XPathContext context, Sequence argument2) throws XPathException {
Item arg2;
try {
arg2 = argument2.head();
} catch (XPathException e) {
String code = e.getErrorCodeLocalPart();
if ("XPDY0002".equals(code) && argument2 instanceof RootExpression) {
throw new XPathException("Cannot call the key() function when there is no context node", "XTDE1270", context);
} else if ("XPDY0050".equals(code)) {
throw new XPathException("In the key() function," +
" the node supplied in the third argument (or the context node if absent)" +
" must be in a tree whose root is a document node", "XTDE1270", context);
} else if ("XPTY0020".equals(code) || "XPTY0019".equals(code)) {
throw new XPathException("Cannot call the key() function when the context item is an atomic value",
"XTDE1270", context);
}
throw e;
}
return arg2;
}
private KeyDefinitionSet getKeyDefinitionSet(KeyManager keyManager, String keyName) throws XPathException {
KeyDefinitionSet selectedKeySet;
StructuredQName qName = null;
try {
qName = StructuredQName.fromLexicalQName(
keyName, false, true,
getNamespaceResolver());
} catch (XPathException err) {
throw new XPathException("Invalid key name: " + err.getMessage(), "XTDE1260");
}
selectedKeySet = keyManager.getKeyDefinitionSet(qName);
if (selectedKeySet == null) {
throw new XPathException("Key '" + keyName + "' has not been defined", "XTDE1260");
}
return selectedKeySet;
}
protected static Sequence search(
final KeyManager keyManager, XPathContext context, Sequence sought, NodeInfo origin, KeyDefinitionSet selectedKeySet) throws XPathException {
NodeInfo doc = origin.getRoot();
if (selectedKeySet.isComposite()) {
SequenceIterator soughtKey = sought.iterate();
SequenceIterator all =
keyManager.selectByCompositeKey(selectedKeySet, doc.getTreeInfo(), soughtKey, context);
if (origin.equals(doc)) {
return new LazySequence(all);
}
return new LazySequence(ItemMappingIterator.filter(all,
item -> Navigator.isAncestorOrSelf(origin, (NodeInfo) item)));
} else {
// Changed by bug 2929 and bug 4656
SequenceIterator allResults = null;
if (sought instanceof AtomicValue) {
SequenceIterator results = keyManager.selectByKey(selectedKeySet, doc.getTreeInfo(), (AtomicValue)sought, context);
if (results instanceof EmptyIterator) {
return EmptySequence.getInstance();
} else if (results instanceof SingletonIterator) {
NodeInfo result = (NodeInfo)results.next();
if (doc.equals(origin) || Navigator.isAncestorOrSelf(origin, result)) {
return result;
} else {
return EmptySequence.getInstance();
}
} else {
if (doc.equals(origin)) {
return new LazySequence(results);
} else {
new LazySequence(ItemMappingIterator.filter(results, item ->
Navigator.isAncestorOrSelf(origin, (NodeInfo) item)));
}
}
}
SequenceIterator keys = sought.iterate();
AtomicValue keyValue;
List allKeyIterators = new ArrayList<>();
while ((keyValue = (AtomicValue) keys.next()) != null) {
SequenceIterator someResults = keyManager.selectByKey(selectedKeySet, doc.getTreeInfo(), keyValue, context);
allKeyIterators.add(someResults);
}
if (allKeyIterators.isEmpty()) {
return EmptySequence.getInstance();
} else if (allKeyIterators.size() == 1) {
allResults = allKeyIterators.get(0);
} else {
allResults = new UnionIterator(allKeyIterators, LocalOrderComparer.getInstance());
}
if (origin.equals(doc)) {
return new LazySequence(allResults);
}
return new LazySequence(ItemMappingIterator.filter(allResults, item ->
Navigator.isAncestorOrSelf(origin, (NodeInfo) item)));
}
}
}