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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.StaticProperty;
import net.sf.saxon.expr.StringLiteral;
import net.sf.saxon.expr.instruct.ForEachGroup;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.expr.parser.RoleDiagnostic;
import net.sf.saxon.expr.parser.TypeChecker;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.lib.StringCollator;
import net.sf.saxon.om.AttributeInfo;
import net.sf.saxon.om.NodeName;
import net.sf.saxon.om.StandardNames;
import net.sf.saxon.pattern.Pattern;
import net.sf.saxon.trans.SaxonErrorCode;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.SpecificFunctionType;
import net.sf.saxon.value.SequenceType;
import net.sf.saxon.value.Whitespace;
import java.net.URI;
import java.net.URISyntaxException;
/**
* Handler for xsl:for-each-group elements in stylesheet. This is a new instruction
* defined in XSLT 2.0
*/
public final class XSLForEachGroup extends StyleElement {
/*@Nullable*/ private Expression select = null;
private Expression groupBy = null;
private Expression groupAdjacent = null;
private Expression breakWhen = null;
private Pattern starting = null;
private Pattern ending = null;
private Expression collationName;
private boolean composite = false;
/**
* 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;
}
/**
* 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() {
String groupByAtt = null;
String groupAdjacentAtt = null;
String startingAtt = null;
String endingAtt = null;
String breakWhenAtt = null;
String collationAtt = null;
for (AttributeInfo att : attributes()) {
NodeName attName = att.getNodeName();
String f = attName.getDisplayName();
String value = att.getValue();
switch (f) {
case "select":
select = makeExpression(value, att);
break;
case "array":
requireXslt40("array");
select = arrayToSequence(makeExpression(value, att));
break;
case "map":
requireXslt40("map");
select = mapToSequence(makeExpression(value, att));
break;
case "group-by":
groupByAtt = value;
groupBy = makeExpression(groupByAtt, att);
break;
case "group-adjacent":
groupAdjacentAtt = value;
groupAdjacent = makeExpression(groupAdjacentAtt, att);
break;
case "group-starting-with":
startingAtt = value;
break;
case "group-ending-with":
endingAtt = value;
break;
case "break-when":
// Saxon extension
requireXslt40("break-when");
breakWhenAtt = "function($group as item()*, $next as item()) as Q{http://www.w3.org/2001/XMLSchema}boolean " +
"{ Q{http://www.w3.org/2005/xpath-functions}boolean(" + value + ") }";
//System.err.println(breakWhenAtt);
breakWhen = makeExpression(breakWhenAtt, att);
break;
case "collation":
collationAtt = Whitespace.trim(value);
collationName = makeAttributeValueTemplate(collationAtt, att);
break;
case "composite":
composite = processBooleanAttribute("composite", value);
break;
default:
checkUnknownAttribute(attName);
break;
}
}
if (select == null) {
select = Literal.makeEmptySequence();
if (getEffectiveVersion() >= 40) {
compileError("One of the attributes select|array|map must be present");
} else {
reportAbsence("select");
}
}
int c = (groupByAtt == null ? 0 : 1) +
(groupAdjacentAtt == null ? 0 : 1) +
(startingAtt == null ? 0 : 1) +
(endingAtt == null ? 0 : 1) +
(breakWhenAtt == null ? 0 : 1);
if (c != 1) {
compileError("Exactly one of the attributes group-by, group-adjacent, group-starting-with, " +
"and group-ending-with must be specified", "XTSE1080"); //TODO: add break-when when it becomes mainstream
}
if (startingAtt != null) {
starting = makePattern(startingAtt, "group-starting-with");
}
if (endingAtt != null) {
ending = makePattern(endingAtt, "group-ending-with");
}
if (collationAtt != null) {
if (groupBy == null && groupAdjacent == null) {
compileError("A collation may be specified only if group-by or group-adjacent is specified", "XTSE1090");
} else {
if (collationName instanceof StringLiteral) {
String collation = ((StringLiteral) collationName).stringify();
URI collationURI;
try {
collationURI = new URI(collation);
if (!collationURI.isAbsolute()) {
URI base = new URI(getBaseURI());
collationURI = base.resolve(collationURI);
collationName = new StringLiteral(collationURI.toString());
}
} catch (URISyntaxException err) {
compileError("Collation name '" + collationName + "' is not a valid URI", "XTDE1110");
collationName = new StringLiteral(NamespaceConstant.CODEPOINT_COLLATION_URI);
}
}
}
} else {
String defaultCollation = getDefaultCollationName();
if (defaultCollation != null) {
collationName = new StringLiteral(defaultCollation);
}
}
if (composite && (starting != null || ending != null)) {
compileError("The composite attribute cannot be used with " +
(starting == null ? "grouping-ending-with" : "group-starting-with"), "XTSE1090");
}
}
@Override
public void validate(ComponentDeclaration decl) throws XPathException {
checkSortComesFirst(false);
TypeChecker tc = getConfiguration().getTypeChecker(false);
select = typeCheck("select", select);
ExpressionVisitor visitor = makeExpressionVisitor();
if (groupBy != null) {
groupBy = typeCheck("group-by", groupBy);
try {
RoleDiagnostic role =
new RoleDiagnostic(RoleDiagnostic.INSTRUCTION, "xsl:for-each-group/group-by", 0);
groupBy = tc.staticTypeCheck(groupBy, SequenceType.ATOMIC_SEQUENCE, role, visitor);
} catch (XPathException err) {
compileError(err);
}
} else if (groupAdjacent != null) {
groupAdjacent = typeCheck("group-adjacent", groupAdjacent);
try {
RoleDiagnostic role =
new RoleDiagnostic(RoleDiagnostic.INSTRUCTION, "xsl:for-each-group/group-adjacent", 0);
role.setErrorCode("XTTE1100");
groupAdjacent = tc.staticTypeCheck(groupAdjacent,
composite ? SequenceType.ATOMIC_SEQUENCE : SequenceType.SINGLE_ATOMIC,
role, visitor);
} catch (XPathException err) {
compileError(err);
}
} else if (breakWhen != null) {
breakWhen = typeCheck("break-when", breakWhen);
try {
SpecificFunctionType breakWhenType = new SpecificFunctionType(
new SequenceType[]{SequenceType.ANY_SEQUENCE, SequenceType.SINGLE_ITEM}, SequenceType.SINGLE_BOOLEAN);
RoleDiagnostic role =
new RoleDiagnostic(RoleDiagnostic.INSTRUCTION, "xsl:for-each-group/break-when", 0);
role.setErrorCode("XTTE1100");
breakWhen = tc.staticTypeCheck(breakWhen,
SequenceType.makeSequenceType(breakWhenType, StaticProperty.EXACTLY_ONE),
role, visitor);
} catch (XPathException err) {
compileError(err);
}
}
starting = typeCheck("group-starting-with", starting);
ending = typeCheck("group-ending-with", ending);
if ((starting != null || ending != null) && visitor.getStaticContext().getXPathVersion() < 30) {
try {
RoleDiagnostic role =
new RoleDiagnostic(RoleDiagnostic.INSTRUCTION, "xsl:for-each-group/select", 0);
role.setErrorCode("XTTE1120");
select = tc.staticTypeCheck(select, SequenceType.NODE_SEQUENCE, role, visitor);
} catch (XPathException err) {
String prefix = starting != null ?
"With group-starting-with attribute: " :
"With group-ending-with attribute: ";
compileError(prefix + err.getMessage(), err.getErrorCodeQName());
}
}
if (!hasChildNodes()) {
compileWarning("An empty xsl:for-each-group instruction has no effect", SaxonErrorCode.SXWN9009);
}
}
@Override
public Expression compile(Compilation compilation, ComponentDeclaration decl) throws XPathException {
StringCollator collator = null;
if (collationName instanceof StringLiteral) {
// if the collation name is constant, then we've already resolved it against the base URI
final String uri = ((StringLiteral) collationName).stringify();
collator = findCollation(uri, getBaseURI());
if (collator == null) {
compileError("The collation name '" + collationName + "' has not been defined", "XTDE1110");
}
}
byte algorithm = ForEachGroup.GROUP_BY;
Expression key = null;
if (groupBy != null) {
algorithm = ForEachGroup.GROUP_BY;
key = groupBy;
} else if (groupAdjacent != null) {
algorithm = ForEachGroup.GROUP_ADJACENT;
key = groupAdjacent;
} else if (starting != null) {
algorithm = ForEachGroup.GROUP_STARTING;
key = starting;
} else if (ending != null) {
algorithm = ForEachGroup.GROUP_ENDING;
key = ending;
} else if (breakWhen != null) {
algorithm = ForEachGroup.GROUP_BREAKING_WHEN;
key = breakWhen;
}
Expression action = compileSequenceConstructor(compilation, decl, true);
if (action == null) {
// body of for-each is empty: it's a no-op.
return Literal.makeEmptySequence();
}
try {
ForEachGroup instr = new ForEachGroup(select,
action.simplify(),
algorithm,
key,
collator,
collationName,
makeSortKeys(compilation, decl));
instr.setIsInFork(getParent().getFingerprint() == StandardNames.XSL_FORK);
instr.setComposite(composite);
return instr;
} catch (XPathException e) {
compileError(e);
return null;
}
}
}