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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2023 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.Expression;
import net.sf.saxon.expr.StringLiteral;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.accum.Accumulator;
import net.sf.saxon.expr.accum.AccumulatorManager;
import net.sf.saxon.expr.accum.AccumulatorRegistry;
import net.sf.saxon.expr.accum.IAccumulatorData;
import net.sf.saxon.om.*;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.trans.XsltController;
import net.sf.saxon.transpile.CSharpSimpleEnum;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.type.Type;
/**
* Non-streaming implementation of accumulator-before() and accumulator-after()
*/
public abstract class AccumulatorFn extends SystemFunction {
@CSharpSimpleEnum
public enum Phase {AFTER, BEFORE, UNSPECIFIED}
public abstract Phase getPhase();
private Sequence getAccumulatorValue(String name, Phase phase, XPathContext context) throws XPathException {
AccumulatorRegistry registry = getRetainedStaticContext().getPackageData().getAccumulatorRegistry();
Accumulator accumulator = getAccumulator(name, registry);
Item node = context.getContextItem();
if (node == null) {
throw new XPathException("No context item for evaluation of accumulator function", "XTDE3350", context);
}
if (!(node instanceof NodeInfo)) {
throw new XPathException("Context item for evaluation of accumulator function must be a node", "XTTE3360", context);
}
int kind = ((NodeInfo)node).getNodeKind();
if (kind == Type.ATTRIBUTE || kind == Type.NAMESPACE) {
throw new XPathException("Context item for evaluation of accumulator function must not be an attribute or namespace node", "XTTE3360", context);
}
Sequence streamedAccVal = registry.getStreamingAccumulatorValue((NodeInfo) node, accumulator, phase);
if (streamedAccVal != null) {
return streamedAccVal;
}
TreeInfo root = ((NodeInfo)node).getTreeInfo();
XsltController controller = (XsltController)context.getController();
if (!accumulator.isUniversallyApplicable() && !controller.getAccumulatorManager().isApplicable(root, accumulator)) {
throw new XPathException("Accumulator " + name + " is not applicable to the current document", "XTDE3362");
}
AccumulatorManager manager = controller.getAccumulatorManager();
IAccumulatorData data = manager.getAccumulatorData(root, accumulator, context);
return data.getValue((NodeInfo) node, phase == Phase.AFTER);
}
/**
* Get the accumulator, given its name
*
* @param name the name (as written - a lexical EQName)
* @param registry the accumulator registry, or null if there are no accumulators registered
* @return the accumulator
* @throws XPathException if the accumulator is not recognised or if the name is invalid
*/
private Accumulator getAccumulator(String name, AccumulatorRegistry registry) throws XPathException {
StructuredQName qName;
try {
qName = StructuredQName.fromLexicalQName(name, false, true, getRetainedStaticContext());
} catch (XPathException err) {
throw new XPathException("Invalid accumulator name: " + err.getMessage(), "XTDE3340");
}
Accumulator accumulator = registry == null ? null : registry.getAccumulator(qName);
if (accumulator == null) {
throw new XPathException("Accumulator " + name + " has not been declared", "XTDE3340");
}
return accumulator;
}
/**
* Get the return type, given knowledge of the actual arguments
*
* @param args the actual arguments supplied
* @return the best available item type that the function will return
*/
@Override
public ItemType getResultItemType(Expression[] args) {
try {
if (args[0] instanceof StringLiteral) {
AccumulatorRegistry registry = getRetainedStaticContext().getPackageData().getAccumulatorRegistry();
Accumulator accumulator = getAccumulator(((StringLiteral) args[0]).stringify(), registry);
return accumulator.getType().getPrimaryType();
}
} catch (Exception e) {
//
}
return super.getResultItemType(args);
}
/**
* Get the cardinality, given knowledge of the actual arguments
*
* @param args the actual arguments supplied
* @return the most precise available cardinality that the function will return
*/
@Override
public int getCardinality(Expression[] args) {
try {
if (args[0] instanceof StringLiteral) {
AccumulatorRegistry registry = getRetainedStaticContext().getPackageData().getAccumulatorRegistry();
Accumulator accumulator = getAccumulator(((StringLiteral) args[0]).stringify(), registry);
return accumulator.getType().getCardinality();
}
} catch (Exception e) {
//
}
return super.getCardinality(args);
}
/**
* Call the Callable.
*
* @param context the dynamic evaluation context
* @param arguments the values of the arguments, supplied as Sequences.
* Generally it is advisable, if calling iterate() to process a supplied sequence, to
* call it only once; if the value is required more than once, it should first be converted
* to a {@link net.sf.saxon.om.GroundedValue} by calling the utility methd
* SequenceTool.toGroundedValue().
* If the expected value is a single item, the item should be obtained by calling
* Sequence.head(): it cannot be assumed that the item will be passed as an instance of
* {@link net.sf.saxon.om.Item} or {@link net.sf.saxon.value.AtomicValue}.
* It is the caller's responsibility to perform any type conversions required
* to convert arguments to the type expected by the callee. An exception is where
* this Callable is explicitly an argument-converting wrapper around the original
* Callable.
* @return the result of the evaluation, in the form of a Sequence. It is the responsibility
* of the callee to ensure that the type of result conforms to the expected result type.
* @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 {
String name = arguments[0].head().getStringValue();
return getAccumulatorValue(name, getPhase(), context);
}
public static class AccumulatorBefore extends AccumulatorFn {
public AccumulatorBefore() {
//System.err.println("acc-before");
}
@Override
public Phase getPhase() {
return Phase.BEFORE;
}
}
public static class AccumulatorAfter extends AccumulatorFn {
@Override
public Phase getPhase() {
return Phase.AFTER;
}
@Override
public String getStreamerName() {
return "AccumulatorAfter";
}
}
}