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The XSLT and XQuery Processor
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2015 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.expr.instruct;
import net.sf.saxon.event.ReceiverOptions;
import net.sf.saxon.expr.*;
import net.sf.saxon.expr.parser.*;
import net.sf.saxon.functions.SystemFunction;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.lib.StandardURIChecker;
import net.sf.saxon.lib.Validation;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.NodeKindTest;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.util.Orphan;
import net.sf.saxon.type.*;
import net.sf.saxon.value.*;
import net.sf.saxon.value.StringValue;
/**
* An instruction derived from an xsl:attribute element in stylesheet, or from
* an attribute constructor in XQuery, in cases where the attribute name is not known
* statically
*/
public final class ComputedAttribute extends AttributeCreator {
private Operand nameOp;
private Operand namespaceOp;
private boolean allowNameAsQName;
/**
* Construct an Attribute instruction
*
* @param attributeName An expression to calculate the attribute name
* @param namespace An expression to calculate the attribute namespace
* @param nsContext a NamespaceContext object containing the static namespace context of the
* stylesheet instruction
* @param validationAction e.g. validation=strict, lax, strip, preserve
* @param schemaType Type against which the attribute must be validated. This must not be a namespace-sensitive
* type; it is the caller's responsibility to check this.
* @param allowNameAsQName true if the attributeName expression is allowed to evaluate to a value
* of type xs:QName (true in XQuery, false in XSLT)
*/
public ComputedAttribute(Expression attributeName,
Expression namespace,
NamespaceResolver nsContext,
int validationAction,
SimpleType schemaType,
boolean allowNameAsQName) {
nameOp = new Operand(this, attributeName, OperandRole.SINGLE_ATOMIC);
if (namespace != null) {
namespaceOp = new Operand(this, namespace, OperandRole.SINGLE_ATOMIC);
}
setSchemaType(schemaType);
setValidationAction(validationAction);
setOptions(0);
this.allowNameAsQName = allowNameAsQName;
}
/**
* Indicate that two attributes with the same name are not acceptable.
* (This option is set in XQuery, but not in XSLT)
*/
public void setRejectDuplicates() {
setOptions(getOptions() | ReceiverOptions.REJECT_DUPLICATES);
}
/**
* Get the name of this instruction
*/
public int getInstructionNameCode() {
return StandardNames.XSL_ATTRIBUTE;
}
/**
* Get the expression used to compute the name of the attribute
*
* @return the expression used to compute the name of the attribute
*/
public Expression getNameExp() {
return nameOp.getChildExpression();
}
/**
* Get the expression used to compute the namespace part of the name of the attribute
*
* @return the expression used to compute the namespace part of the name of the attribute
*/
public Expression getNamespaceExp() {
return namespaceOp == null ? null : namespaceOp.getChildExpression();
}
public void setNameExp(Expression attributeName) {
nameOp.setChildExpression(attributeName);
}
public void setNamespace(Expression namespace) {
if (namespace != null) {
if (namespaceOp == null) {
namespaceOp = new Operand(this, namespace, OperandRole.SINGLE_ATOMIC);
} else {
namespaceOp.setChildExpression(namespace);
}
}
}
@Override
public Iterable operands() {
return operandSparseList(selectOp, nameOp, namespaceOp);
}
/**
* Get the namespace resolver used to resolve any prefix in the name of the attribute
*
* @return the namespace resolver if one has been saved; or null otherwise
*/
public NamespaceResolver getNamespaceResolver() {
return getRetainedStaticContext();
}
/**
* Get the static type of this expression
*
* @return the static type of the item returned by this expression
*/
/*@NotNull*/
public ItemType getItemType() {
return NodeKindTest.ATTRIBUTE;
}
/**
* Get the static cardinality of this expression
*
* @return the static cardinality (exactly one)
*/
public int getCardinality() {
return StaticProperty.ALLOWS_ZERO_OR_ONE;
}
/**
* Ask whether it is allowed for the name to be evaluted as an xs:QName instance (true in XQuery)
*
* @return the boolean if name is allowed as a QName
*/
public boolean isAllowNameAsQName() {
return allowNameAsQName;
}
/**
* 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.
*
* @return a set of flags indicating static properties of this expression
*/
public int computeSpecialProperties() {
return super.computeSpecialProperties() |
StaticProperty.SINGLE_DOCUMENT_NODESET;
}
public void localTypeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException {
nameOp.typeCheck(visitor, contextItemType);
RoleDiagnostic role = new RoleDiagnostic(RoleDiagnostic.INSTRUCTION, "attribute/name", 0);
if (allowNameAsQName) {
// Can only happen in XQuery
setNameExp(TypeChecker.staticTypeCheck(getNameExp(),
SequenceType.SINGLE_ATOMIC, false, role, visitor));
TypeHierarchy th = getConfiguration().getTypeHierarchy();
ItemType nameItemType = getNameExp().getItemType();
boolean maybeString = th.relationship(nameItemType, BuiltInAtomicType.STRING) != TypeHierarchy.DISJOINT ||
th.relationship(nameItemType, BuiltInAtomicType.UNTYPED_ATOMIC) != TypeHierarchy.DISJOINT;
boolean maybeQName = th.relationship(nameItemType, BuiltInAtomicType.QNAME) != TypeHierarchy.DISJOINT;
if (!(maybeString || maybeQName)) {
XPathException err = new XPathException(
"The attribute name must be either an xs:string, an xs:QName, or untyped atomic");
err.setErrorCode("XPTY0004");
err.setIsTypeError(true);
err.setLocation(getLocation());
throw err;
}
} else {
TypeHierarchy th = getConfiguration().getTypeHierarchy();
if (!th.isSubType(getNameExp().getItemType(), BuiltInAtomicType.STRING)) {
setNameExp(SystemFunction.makeCall("string", getRetainedStaticContext(), getNameExp()));
}
}
if (getNamespaceExp() != null) {
namespaceOp.typeCheck(visitor, contextItemType);
// Deleted MHK Aug 2014 because the namespace expression is an AVT and therefore necessarily a string
// role = new RoleLocator(RoleLocator.INSTRUCTION, "attribute/namespace", 0);
// namespace = TypeChecker.staticTypeCheck(
// namespace, SequenceType.SINGLE_STRING, false, role, visitor);
}
if (Literal.isAtomic(getNameExp())) {
// Check we have a valid lexical QName, whose prefix is in scope where necessary
try {
AtomicValue val = (AtomicValue) ((Literal) getNameExp()).getValue();
if (val instanceof StringValue) {
String[] parts = NameChecker.checkQNameParts(val.getStringValueCS());
if (getNamespaceExp() == null) {
String uri = getNamespaceResolver().getURIForPrefix(parts[0], true);
if (uri == null) {
XPathException se = new XPathException("Prefix " + parts[0] + " has not been declared");
if (isXSLT()) {
se.setErrorCode("XTDE0860");
se.setIsStaticError(true);
throw se;
} else {
se.setErrorCode("XQDY0074");
se.setIsStaticError(false);
throw se;
}
}
setNamespace(new StringLiteral(uri));
}
}
} catch (XPathException e) {
if (e.getErrorCodeQName() == null || e.getErrorCodeLocalPart().equals("FORG0001")) {
e.setErrorCode(isXSLT() ? "XTDE0850" : "XQDY0074");
}
e.maybeSetLocation(getLocation());
e.setIsStaticError(true);
throw e;
}
}
}
/*@NotNull*/
public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException {
Expression exp = super.optimize(visitor, contextItemType);
if (exp != this) {
return exp;
}
// If the name is known statically, use a FixedAttribute instead
if (getNameExp() instanceof Literal && (getNamespaceExp() == null || getNamespaceExp() instanceof Literal)) {
XPathContext context = visitor.getStaticContext().makeEarlyEvaluationContext();
NodeName nc = evaluateNodeName(context);
FixedAttribute fa = new FixedAttribute(nc, getValidationAction(), getSchemaType());
fa.setSelect(getSelect());
return fa;
}
return this;
}
/**
* Copy an expression. This makes a deep copy.
*
* @return the copy of the original expression
*/
/*@NotNull*/
public Expression copy() {
ComputedAttribute exp = new ComputedAttribute(
getNameExp() == null ? null : getNameExp().copy(),
getNamespaceExp() == null ? null : getNamespaceExp().copy(),
getRetainedStaticContext(), getValidationAction(), getSchemaType(), allowNameAsQName);
ExpressionTool.copyLocationInfo(this, exp);
exp.setSelect(getSelect().copy());
return exp;
}
/**
* Offer promotion for subexpressions. The offer will be accepted if the subexpression
* is not dependent on the factors (e.g. the context item) identified in the PromotionOffer.
* By default the offer is not accepted - this is appropriate in the case of simple expressions
* such as constant values and variable references where promotion would give no performance
* advantage. This method is always called at compile time.
*
* @param offer details of the offer, for example the offer to move
* expressions that don't depend on the context to an outer level in
* the containing expression
* @throws XPathException if any error is detected
*/
protected void promoteChildren(PromotionOffer offer) throws XPathException {
setNameExp(doPromotion(getNameExp(), offer));
if (getNamespaceExp() != null) {
setNamespace(doPromotion(getNamespaceExp(), offer));
}
super.promoteChildren(offer);
}
/**
* Check that any elements and attributes constructed or returned by this expression are acceptable
* in the content model of a given complex type. It's always OK to say yes, since the check will be
* repeated at run-time. The process of checking element and attribute constructors against the content
* model of a complex type also registers the type of content expected of those constructors, so the
* static validation can continue recursively.
*/
public void checkPermittedContents(SchemaType parentType, boolean whole) throws XPathException {
if (parentType instanceof SimpleType) {
String msg = "Attributes are not permitted here: ";
if (parentType.isAnonymousType()) {
msg += "the containing element is defined to have a simple type";
} else {
msg += "the containing element is of simple type " + parentType.getDescription();
}
XPathException err = new XPathException(msg);
err.setIsTypeError(true);
err.setLocation(getLocation());
throw err;
}
}
/**
* Determine the name to be used for the attribute, as an integer name code
*
* @param context Dynamic evaluation context
* @return the integer name code for the attribute name
* @throws XPathException
*/
public NodeName evaluateNodeName(XPathContext context) throws XPathException {
NamePool pool = context.getNamePool();
Item nameValue = getNameExp().evaluateItem(context);
String prefix;
String localName;
String uri = null;
if (nameValue instanceof StringValue) {
// this will always be the case in XSLT
CharSequence rawName = nameValue.getStringValueCS();
rawName = Whitespace.trimWhitespace(rawName); // required in XSLT; possibly wrong in XQuery
try {
String[] parts = NameChecker.getQNameParts(rawName);
prefix = parts[0];
localName = parts[1];
} catch (QNameException err) {
String errorCode = isXSLT() ? "XTDE0850" : "XQDY0074";
XPathException err1 = new XPathException("Invalid attribute name: " + rawName, errorCode, this.getLocation());
throw dynamicError(getLocation(), err1, context);
}
if (rawName.toString().equals("xmlns")) {
if (getNamespaceExp() == null) {
String errorCode = isXSLT() ? "XTDE0855" : "XQDY0044";
XPathException err = new XPathException("Invalid attribute name: " + rawName, errorCode, this.getLocation());
throw dynamicError(getLocation(), err, context);
}
}
if (prefix.equals("xmlns")) {
if (getNamespaceExp() == null) {
String errorCode = isXSLT() ? "XTDE0860" : "XQDY0044";
XPathException err = new XPathException("Invalid attribute name: " + rawName, errorCode, this.getLocation());
throw dynamicError(getLocation(), err, context);
} else {
// ignore the prefix "xmlns"
prefix = "";
}
}
} else if (nameValue instanceof QNameValue && allowNameAsQName) {
// this is allowed in XQuery
localName = ((QNameValue) nameValue).getLocalName();
uri = ((QNameValue) nameValue).getNamespaceURI();
if (localName.equals("xmlns") && uri.isEmpty()) {
XPathException err = new XPathException("Invalid attribute name: xmlns", "XQDY0044", this.getLocation());
throw dynamicError(getLocation(), err, context);
}
if (uri.isEmpty()) {
prefix = "";
} else {
prefix = ((QNameValue) nameValue).getPrefix();
if (prefix.isEmpty()) {
prefix = pool.suggestPrefixForURI(uri);
if (prefix == null) {
prefix = "ns0";
// If the prefix is a duplicate, a different one will be substituted
}
}
if (uri.equals(NamespaceConstant.XML) != "xml".equals(prefix)) {
String message;
if ("xml".equals(prefix)) {
message = "When the prefix is 'xml', the namespace URI must be " + NamespaceConstant.XML;
} else {
message = "When the namespace URI is " + NamespaceConstant.XML + ", the prefix must be 'xml'";
}
String errorCode = isXSLT() ? "XTDE0835" : "XQDY0044";
XPathException err = new XPathException(message, errorCode, this.getLocation());
throw dynamicError(getLocation(), err, context);
}
}
if ("xmlns".equals(prefix)) {
XPathException err = new XPathException("Invalid attribute namespace: http://www.w3.org/2000/xmlns/", "XQDY0044", this.getLocation());
throw dynamicError(getLocation(), err, context);
}
} else {
XPathException err = new XPathException("Attribute name must be either a string or a QName", "XPTY0004", this.getLocation());
err.setIsTypeError(true);
throw dynamicError(getLocation(), err, context);
}
if (getNamespaceExp() == null && uri == null) {
if (prefix.isEmpty()) {
uri = "";
} else {
uri = getRetainedStaticContext().getURIForPrefix(prefix, false);
if (uri == null) {
String errorCode = isXSLT() ? "XTDE0860" : "XQDY0074";
XPathException err = new XPathException("Undeclared prefix in attribute name: " + prefix, errorCode, this.getLocation());
throw dynamicError(getLocation(), err, context);
}
}
} else {
if (uri == null) {
// generate a name using the supplied namespace URI
if (getNamespaceExp() instanceof StringLiteral) {
uri = ((StringLiteral) getNamespaceExp()).getStringValue();
} else {
uri = getNamespaceExp().evaluateAsString(context).toString();
if (!StandardURIChecker.getInstance().isValidURI(uri)) {
XPathException de = new XPathException("The value of the namespace attribute must be a valid URI", "XTDE0865", this.getLocation());
throw dynamicError(getLocation(), de, context);
}
}
}
if (uri.isEmpty()) {
// there is a special rule for this case in the XSLT specification;
// we force the attribute to go in the null namespace
prefix = "";
} else {
// if a suggested prefix is given, use it; otherwise try to find a prefix
// associated with this URI; if all else fails, invent one.
if (prefix.isEmpty()) {
prefix = pool.suggestPrefixForURI(uri);
if (prefix == null) {
prefix = "ns0";
// this will be replaced later if it is already in use
}
}
}
}
if (uri.equals(NamespaceConstant.XMLNS)) {
String errorCode = isXSLT() ? "XTDE0865" : "XQDY0044";
XPathException err = new XPathException("Cannot create attribute in namespace " + uri, errorCode, this.getLocation());
throw dynamicError(getLocation(), err, context);
}
return new FingerprintedQName(prefix, uri, localName);
}
@Override
public Item evaluateItem(XPathContext context) throws XPathException {
Item node = super.evaluateItem(context);
validateOrphanAttribute((Orphan) node, context);
return node;
}
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*/
public void export(ExpressionPresenter out) {
out.startElement("compAtt", this);
if (getValidationAction() != Validation.SKIP) {
out.emitAttribute("validation", Validation.toString(getValidationAction()));
}
SimpleType type = getSchemaType();
if (type != null) {
out.emitAttribute("type", type.getStructuredQName().getEQName());
}
out.setChildRole("name");
getNameExp().export(out);
if (getNamespaceExp() != null) {
out.setChildRole("namespace");
getNamespaceExp().export(out);
}
out.setChildRole("select");
getSelect().export(out);
out.endElement();
}
}
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