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An OSGi bundle for Saxon-HE
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 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.ExpressionTool;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.expr.parser.Optimizer;
import net.sf.saxon.expr.parser.PathMap;
import net.sf.saxon.expr.sort.DocumentOrderIterator;
import net.sf.saxon.expr.sort.LocalOrderComparer;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.NodeKindTest;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.iter.EmptyIterator;
import net.sf.saxon.tree.iter.SingletonIterator;
import net.sf.saxon.type.Type;
import net.sf.saxon.value.*;
import net.sf.saxon.value.StringValue;
/**
* The XPath id() or element-with-id() function
* XPath 2.0 version: accepts any sequence as the first parameter; each item in the sequence
* is taken as an IDREFS value, that is, a space-separated list of ID values.
* Also accepts an optional second argument to identify the target document, this
* defaults to the context node.
*/
public class Id extends SystemFunctionCall implements Callable {
public static final int ID = 0;
public static final int ELEMENT_WITH_ID = 1;
private boolean isSingletonId = false;
/**
* Simplify: add a second implicit argument, the context document
* @param visitor an expression visitor
*/
/*@NotNull*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
Id id = (Id)super.simplify(visitor);
if (argument.length == 1) {
id.addContextDocumentArgument(1, getFunctionName().getLocalPart());
}
return id;
}
/**
* Type-check the expression. This also calls preEvaluate() to evaluate the function
* if all the arguments are constant; functions that do not require this behavior
* can override the preEvaluate method.
*/
/*@NotNull*/
public Expression typeCheck(ExpressionVisitor visitor, /*@Nullable*/ ExpressionVisitor.ContextItemType contextItemType) throws XPathException {
if (argument[1] instanceof RootExpression &&
contextItemType != null && contextItemType.itemType != null &&
contextItemType.itemType.isPlainType()) {
// intercept this to get better diagnostics
XPathException err = new XPathException(getFunctionName().getLocalPart() +
"() function called when the context item is not a node");
err.setErrorCode("XPTY0004");
err.setLocator(this);
throw err;
}
return super.typeCheck(visitor, contextItemType);
}
/**
* Static analysis: prevent sorting of the argument
*/
public void checkArguments(/*@NotNull*/ ExpressionVisitor visitor) throws XPathException {
super.checkArguments(visitor);
Optimizer opt = visitor.getConfiguration().obtainOptimizer();
argument[0] = ExpressionTool.unsorted(opt, argument[0], false);
isSingletonId = !Cardinality.allowsMany(argument[0].getCardinality());
}
/**
* preEvaluate: this method suppresses compile-time evaluation by doing nothing
* @param visitor an expression visitor
*/
public Expression preEvaluate(ExpressionVisitor visitor) {
return this;
}
/**
* 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
* property bit is set, it is true, but if it is unset, the value is unknown.
*/
public int computeSpecialProperties() {
int prop = StaticProperty.ORDERED_NODESET |
StaticProperty.SINGLE_DOCUMENT_NODESET |
StaticProperty.NON_CREATIVE;
if ((getNumberOfArguments() == 1) ||
(argument[1].getSpecialProperties() & StaticProperty.CONTEXT_DOCUMENT_NODESET) != 0) {
prop |= StaticProperty.CONTEXT_DOCUMENT_NODESET;
}
return prop;
}
/**
* Add a representation of a doc() call or similar function to a PathMap.
* This is a convenience method called by the addToPathMap() methods for doc(), document(), collection()
* and similar functions. These all create a new root expression in the path map.
*
* @param pathMap the PathMap to which the expression should be added
* @param pathMapNodeSet
* @return the pathMapNode representing the focus established by this expression, in the case where this
* expression is the first operand of a path expression or filter expression
*/
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) {
argument[0].addToPathMap(pathMap, pathMapNodeSet);
PathMap.PathMapNodeSet target = argument[1].addToPathMap(pathMap, pathMapNodeSet);
// indicate that the function navigates to all elements in the document
target = target.createArc(AxisInfo.DESCENDANT, NodeKindTest.ELEMENT);
return target;
}
/**
* Evaluate the function to return an iteration of selected nodes.
*/
/*@NotNull*/
public SequenceIterator iterate(XPathContext context) throws XPathException {
NodeInfo arg1;
try {
arg1 = (NodeInfo)argument[1].evaluateItem(context);
} catch (XPathException e) {
if (context.getContextItem() instanceof AtomicValue) {
// Override the unhelpful message that trickles down...
XPathException e2 = new XPathException("id() function called when the context item is not a node");
e2.setErrorCode("XPTY0004");
e2.setXPathContext(context);
e2.setLocator(this);
throw e2;
} else {
throw e;
}
}
arg1 = arg1.getRoot();
if (arg1.getNodeKind() != Type.DOCUMENT) {
dynamicError("In the " + getFunctionName().getLocalPart() + "() function," +
" the tree being searched must be one whose root is a document node", "FODC0001", context);
return null;
}
DocumentInfo doc = (DocumentInfo)arg1;
if (isSingletonId) {
AtomicValue arg = (AtomicValue)argument[0].evaluateItem(context);
if (arg==null) {
return EmptyIterator.getInstance();
}
String idrefs = arg.getStringValue();
return getIdSingle(doc, idrefs, operation);
} else {
SequenceIterator idrefs = argument[0].iterate(context);
return getIdMultiple(doc, idrefs, operation);
}
}
/**
* Get an iterator over the nodes that have an id equal to one of the values is a whitespace separated
* string
* @param doc The document to be searched
* @param idrefs a string containing zero or more whitespace-separated ID values to be found in the document
* @param operation either {@link #ID} or {@link #ELEMENT_WITH_ID}
* @return an iterator over the nodes whose ID is one of the specified values
* @throws XPathException
*/
public static SequenceIterator getIdSingle(DocumentInfo doc, String idrefs, int operation) throws XPathException {
boolean white = false;
for (int i=idrefs.length()-1; i>=0; i--) {
char c = idrefs.charAt(i);
if (c <= 0x20 && (c == 0x20 || c == 0x09 || c == 0x0a || c == 0x0d)) {
white = true;
break;
}
}
if (white) {
StringTokenIterator tokens = new StringTokenIterator(idrefs);
IdMappingFunction map = new IdMappingFunction();
map.document = doc;
map.operation = operation;
SequenceIterator result = new MappingIterator(tokens, map);
return new DocumentOrderIterator(result, LocalOrderComparer.getInstance());
} else {
return SingletonIterator.makeIterator(doc.selectID(idrefs, operation == ELEMENT_WITH_ID));
}
}
/**
* Get an iterator over the nodes that have an id equal to one of the values is a set of whitespace separated
* strings
* @param doc The document to be searched
* @param idrefs an iterator over a set of strings each of which is a string containing
* zero or more whitespace-separated ID values to be found in the document
* @return an iterator over the nodes whose ID is one of the specified values
* @throws XPathException
*/
public static SequenceIterator getIdMultiple(DocumentInfo doc, SequenceIterator idrefs, int operation) throws XPathException {
IdMappingFunction map = new IdMappingFunction();
map.document = doc;
map.operation = operation;
SequenceIterator result = new MappingIterator(idrefs, map);
return new DocumentOrderIterator(result, LocalOrderComparer.getInstance());
}
/**
* Evaluate the expression
*
*
*
* @param context the dynamic evaluation context
* @param arguments the values of the arguments, supplied as SequenceIterators
* @return the result of the evaluation, in the form of a SequenceIterator
* @throws net.sf.saxon.trans.XPathException
* if a dynamic error occurs during the evaluation of the expression
*/
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
NodeInfo start = (arguments.length == 1 ? getContextNode(context) : (NodeInfo)arguments[1].head());
NodeInfo arg1 = start.getRoot();
if (arg1.getNodeKind() != Type.DOCUMENT) {
dynamicError("In the " + getFunctionName().getLocalPart() + "() function," +
" the tree being searched must be one whose root is a document node", "FODC0001", context);
return null;
}
DocumentInfo doc = (DocumentInfo)arg1;
SequenceIterator idrefs = arguments[0].iterate();
return SequenceTool.toLazySequence(getIdMultiple(doc, idrefs, operation));
}
private static class IdMappingFunction implements MappingFunction {
public DocumentInfo document;
private int operation;
/**
* Evaluate the function for a single string value
* (implements the MappingFunction interface)
*/
public SequenceIterator map(StringValue item) throws XPathException {
String idrefs = Whitespace.trim(item.getStringValueCS());
// If this value contains a space, we need to break it up into its
// separate tokens; if not, we can process it directly
if (Whitespace.containsWhitespace(idrefs)) {
StringTokenIterator tokens = new StringTokenIterator(idrefs);
IdMappingFunction submap = new IdMappingFunction();
submap.document = document;
submap.operation = operation;
return new MappingIterator(tokens, submap);
} else {
return SingletonIterator.makeIterator(document.selectID(idrefs, operation == ELEMENT_WITH_ID));
}
}
}
}