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The XSLT and XQuery Processor
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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.style;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.Literal;
import net.sf.saxon.expr.StringLiteral;
import net.sf.saxon.expr.instruct.ForEach;
import net.sf.saxon.expr.sort.SortExpression;
import net.sf.saxon.expr.sort.SortKeyDefinitionList;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.AttributeInfo;
import net.sf.saxon.om.NodeName;
import net.sf.saxon.trans.SaxonErrorCode;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.Cardinality;
import net.sf.saxon.value.Whitespace;
/**
* Handler for xsl:for-each elements in stylesheet.
*/
public class XSLForEach extends StyleElement {
/*@Nullable*/ private Expression select = null;
private boolean containsTailCall = false;
private Expression threads = null;
private Expression separator = null;
/**
* Determine whether this node is an instruction.
*
* @return true - it is an instruction
*/
@Override
public boolean isInstruction() {
return true;
}
/**
* Specify that xsl:sort is a permitted child
*/
@Override
protected boolean isPermittedChild(StyleElement child) {
return (child instanceof XSLSort);
}
@Override
protected boolean markTailCalls() {
assert select != null;
if (Cardinality.allowsMany(select.getCardinality())) {
return false;
} else {
StyleElement last = getLastChildInstruction();
containsTailCall = last != null && last.markTailCalls();
return containsTailCall;
}
}
/**
* Determine whether this type of element is allowed to contain a template-body
*
* @return true: yes, it may contain a template-body
*/
@Override
protected boolean mayContainSequenceConstructor() {
return true;
}
@Override
protected void prepareAttributes() {
for (AttributeInfo att : attributes()) {
NodeName attName = att.getNodeName();
String f = attName.getDisplayName();
String value = att.getValue();
if (f.equals("select")) {
select = makeExpression(value, att);
} else if (f.equals("array")) {
requireXslt40("array");
select = arrayToSequence(makeExpression(value, att));
} else if (f.equals("map")) {
requireXslt40("map");
select = mapToSequence(makeExpression(value, att));
} else if (f.equals("separator")) {
requireXslt40("separator");
separator = makeAttributeValueTemplate(value, att);
} else if (attName.getLocalPart().equals("threads") && attName.hasURI(NamespaceConstant.SAXON)) {
threads = makeAttributeValueTemplate(Whitespace.trim(value), att);
if (getCompilation().getCompilerInfo().isCompileWithTracing()) {
compileWarning("saxon:threads - no multithreading takes place when compiling with trace enabled",
SaxonErrorCode.SXWN9012);
threads = new StringLiteral("0");
} else if (!"EE".equals(getConfiguration().getEditionCode())) {
compileWarning("saxon:threads - ignored when not running Saxon-EE",
SaxonErrorCode.SXWN9013);
threads = new StringLiteral("0");
}
} else {
checkUnknownAttribute(attName);
}
}
if (select == null) {
if (getEffectiveVersion() >= 40) {
compileError("One of the attributes select|array|map must be present");
} else {
reportAbsence("select");
}
select = Literal.makeEmptySequence();
}
}
@Override
public void validate(ComponentDeclaration decl) throws XPathException {
checkSortComesFirst(false);
select = typeCheck("select", select);
if (separator != null) {
separator = typeCheck("separator", separator);
}
if (threads != null) {
threads = typeCheck("threads", threads);
}
if (!hasChildNodes()) {
compileWarning("An empty xsl:for-each instruction has no effect", SaxonErrorCode.SXWN9009);
}
}
@Override
public Expression compile(Compilation compilation, ComponentDeclaration decl) throws XPathException {
SortKeyDefinitionList sortKeys = makeSortKeys(compilation, decl);
Expression sortedSequence = select;
if (sortKeys != null) {
sortedSequence = new SortExpression(select, sortKeys);
}
Expression block = compileSequenceConstructor(compilation, decl, true);
if (block == null) {
// body of for-each is empty: it's a no-op.
return Literal.makeEmptySequence();
}
try {
ForEach result = new ForEach(sortedSequence, block.simplify(), containsTailCall, threads);
result.setInstruction(true);
result.setLocation(allocateLocation());
if (separator != null) {
result.setSeparatorExpression(separator);
}
return result;
} catch (XPathException err) {
compileError(err);
return null;
}
}
}