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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.style;
import net.sf.saxon.expr.Component;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.Literal;
import net.sf.saxon.expr.TailCallLoop;
import net.sf.saxon.expr.instruct.SlotManager;
import net.sf.saxon.expr.instruct.UserFunction;
import net.sf.saxon.expr.instruct.UserFunctionParameter;
import net.sf.saxon.expr.parser.*;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.*;
import net.sf.saxon.trace.LocationKind;
import net.sf.saxon.trans.*;
import net.sf.saxon.tree.iter.AxisIterator;
import net.sf.saxon.value.SequenceType;
import net.sf.saxon.value.Whitespace;
/**
* Handler for xsl:function elements in stylesheet (XSLT 2.0).
* Attributes:
* name gives the name of the function
* saxon:memo-function=yes|no indicates whether it acts as a memo function.
*/
public class XSLFunction extends StyleElement implements StylesheetComponent {
private boolean doneAttributes = false;
/*@Nullable*/ private String nameAtt = null;
private String asAtt = null;
private SequenceType resultType;
private SlotManager stackFrameMap;
private boolean memoFunction = false;
private String overrideExtensionFunctionAtt = null;
private boolean overrideExtensionFunction = true;
private int numberOfArguments = -1; // -1 means not yet known
private UserFunction compiledFunction;
private Visibility visibility;
private FunctionStreamability streamability;
private UserFunction.Determinism determinism = UserFunction.Determinism.PROACTIVE;
/**
* Get the corresponding Procedure object that results from the compilation of this
* StylesheetProcedure
*/
public UserFunction getCompiledProcedure() {
return compiledFunction;
}
/**
* Ask whether this node is a declaration, that is, a permitted child of xsl:stylesheet
* (including xsl:include and xsl:import).
*
* @return true for this element
*/
@Override
public boolean isDeclaration() {
return true;
}
public void prepareAttributes() throws XPathException {
if (doneAttributes) {
return;
}
doneAttributes = true;
AttributeCollection atts = getAttributeList();
overrideExtensionFunctionAtt = null;
String visibilityAtt = null;
String cacheAtt = null;
String newEachTimeAtt = null;
String streamabilityAtt = null;
for (int a = 0; a < atts.getLength(); a++) {
String uri = atts.getURI(a);
String local = atts.getLocalName(a);
if ("".equals(uri)) {
if (local.equals("name")) {
nameAtt = Whitespace.trim(atts.getValue(a));
assert nameAtt != null;
if (nameAtt.indexOf(':') < 0) {
nameAtt = "Q{" + NamespaceConstant.SAXON + "}error-function-name";
compileError("Function name must have a namespace prefix", "XTSE0740");
}
try {
setObjectName(makeQName(nameAtt));
} catch (NamespaceException err) {
compileError(err.getMessage(), "XTSE0280");
} catch (XPathException err) {
compileError(err);
}
} else if (local.equals("as")) {
asAtt = atts.getValue(a);
} else if (local.equals("visibility")) {
visibilityAtt = Whitespace.trim(atts.getValue(a));
} else if (local.equals("streamability")) {
streamabilityAtt = Whitespace.trim(atts.getValue(a));
} else if (local.equals("override")) {
String overrideAtt = Whitespace.trim(atts.getValue(a));
boolean override = processBooleanAttribute("override", overrideAtt);
if (overrideExtensionFunctionAtt != null) {
if (override != overrideExtensionFunction) {
compileError("Attributes override-extension-function and override are both used, but do not match", "XTSE0020");
}
} else {
overrideExtensionFunctionAtt = overrideAtt;
overrideExtensionFunction = override;
}
if (isXslt30Processor()) {
compileWarning("The xsl:function/@override attribute is deprecated; use override-extension-function", SaxonErrorCode.SXWN9014);
}
} else if (local.equals("override-extension-function") && isXslt30Processor()) {
String overrideExtAtt = Whitespace.trim(atts.getValue(a));
boolean overrideExt = processBooleanAttribute("override-extension-function", overrideExtAtt);
if (overrideExtensionFunctionAtt != null) {
if (overrideExt != overrideExtensionFunction) {
compileError("Attributes override-extension-function and override are both used, but do not match", "XTSE0020");
}
} else {
overrideExtensionFunctionAtt = overrideExtAtt;
overrideExtensionFunction = overrideExt;
}
if (local.equals("override")) {
compileWarning("The xsl:function/@override attribute is deprecated; use override-extension-function", SaxonErrorCode.SXWN9014);
}
} else if (local.equals("cache")) {
cacheAtt = Whitespace.trim(atts.getValue(a));
} else if (local.equals("new-each-time")) {
newEachTimeAtt = Whitespace.trim(atts.getValue(a));
} else {
checkUnknownAttribute(atts.getNodeName(a));
}
} else if (local.equals("memo-function") && uri.equals(NamespaceConstant.SAXON)) {
memoFunction = processBooleanAttribute("saxon:memo-function", atts.getValue(a));
} else {
checkUnknownAttribute(atts.getNodeName(a));
}
}
if (nameAtt == null) {
reportAbsence("name");
nameAtt = "xsl:unnamed-function-" + generateId();
}
if (asAtt == null) {
resultType = SequenceType.ANY_SEQUENCE;
} else {
resultType = makeSequenceType(asAtt);
}
if (visibilityAtt == null) {
visibility = Visibility.PRIVATE;
} else {
check30attribute("visibility");
visibility = interpretVisibilityValue(visibilityAtt, "");
}
if (streamabilityAtt == null) {
streamability = FunctionStreamability.UNCLASSIFIED;
} else {
check30attribute("streamability");
streamability = getStreamabilityValue(streamabilityAtt);
}
if (newEachTimeAtt != null) {
if ("maybe".equals(newEachTimeAtt)) {
determinism = UserFunction.Determinism.ELIDABLE;
} else {
try {
boolean b = processBooleanAttribute("new-each-time", newEachTimeAtt);
determinism = b ? UserFunction.Determinism.PROACTIVE : UserFunction.Determinism.DETERMINISTIC;
} catch (XPathException e) {
invalidAttribute("new-each-time", "yes|no|maybe");
}
}
}
boolean cache = false;
if (cacheAtt != null) {
cache = processBooleanAttribute("cache", cacheAtt);
}
if (determinism == UserFunction.Determinism.DETERMINISTIC || cache) {
memoFunction = true;
}
}
private FunctionStreamability getStreamabilityValue(String s) throws XPathException {
if (s.contains(":")) {
// QNames are allowed but not recognized by Saxon
try {
makeQName(s);
} catch (NamespaceException e) {
throw new XPathException(e);
}
return FunctionStreamability.UNCLASSIFIED;
}
for (FunctionStreamability v : FunctionStreamability.values()) {
if (v.streamabilityStr.equals(s)) {
return v;
}
}
invalidAttribute("visibility", "unclassified|absorbing|inspection|filter|shallow-descent|deep-descent|ascent");
return null;
}
/**
* Get a name identifying the object of the expression, for example a function name, template name,
* variable name, key name, element name, etc. This is used only where the name is known statically.
* If there is no name, the value will be -1.
*/
/*@NotNull*/
public StructuredQName getObjectName() {
StructuredQName qn = super.getObjectName();
if (qn == null) {
nameAtt = Whitespace.trim(getAttributeValue("", "name"));
if (nameAtt == null) {
return new StructuredQName("saxon", NamespaceConstant.SAXON, "badly-named-function" + generateId());
}
try {
qn = makeQName(nameAtt);
setObjectName(qn);
} catch (NamespaceException err) {
return new StructuredQName("saxon", NamespaceConstant.SAXON, "badly-named-function" + generateId());
} catch (XPathException err) {
return new StructuredQName("saxon", NamespaceConstant.SAXON, "badly-named-function" + generateId());
}
}
return qn;
}
/**
* Determine whether this type of element is allowed to contain a template-body.
*
* @return true: yes, it may contain a general template-body
*/
public boolean mayContainSequenceConstructor() {
return true;
}
protected boolean mayContainParam(String attName) {
return !"required".equals(attName);
}
/**
* Specify that xsl:param is a permitted child
*/
protected boolean isPermittedChild(StyleElement child) {
return child instanceof XSLLocalParam;
}
public Visibility getVisibility() {
if (visibility == null) {
try {
String vAtt = getAttributeValue("", "visibility");
return vAtt == null ? Visibility.PRIVATE : interpretVisibilityValue(Whitespace.trim(vAtt), "");
} catch (XPathException e) {
return Visibility.PRIVATE;
}
}
return visibility;
}
public SymbolicName getSymbolicName() {
return new SymbolicName(StandardNames.XSL_FUNCTION, getObjectName(), getNumberOfArguments());
}
public void checkCompatibility(Component component) throws XPathException {
if (compiledFunction == null) {
getCompiledFunction();
}
UserFunction other = (UserFunction) component.getCode();
if (!compiledFunction.getSymbolicName().equals(other.getSymbolicName())) {
// Can't happen
compileError("The overriding xsl:function " + nameAtt + " does not match the overridden function: " +
"the function name/arity does not match", "XTSE3070");
}
if (!compiledFunction.getResultType().equals(other.getResultType())) {
compileError("The overriding xsl:function " + nameAtt + " does not match the overridden function: " +
"the return type does not match", "XTSE3070");
}
if (!compiledFunction.getDeclaredStreamability().equals(other.getDeclaredStreamability())) {
compileError("The overriding xsl:function " + nameAtt + " does not match the overridden function: " +
"the streamability category does not match", "XTSE3070");
}
if (!compiledFunction.getDeterminism().equals(other.getDeterminism())) {
compileError("The overriding xsl:function " + nameAtt + " does not match the overridden function: " +
"the new-each-time attribute does not match", "XTSE3070");
}
for (int i = 0; i < getNumberOfArguments(); i++) {
if (!compiledFunction.getArgumentType(i).equals(other.getArgumentType(i))) {
compileError("The overriding xsl:function " + nameAtt + " does not match the overridden function: " +
"the type of the " + RoleDiagnostic.ordinal(i + 1) + " argument does not match", "XTSE3070");
}
}
}
/**
* Is override-extension-function="yes"?.
*
* @return true if override-extension-function="yes" was specified, otherwise false
*/
public boolean isOverrideExtensionFunction() {
if (overrideExtensionFunctionAtt == null) {
// this is a forwards reference
try {
prepareAttributes();
} catch (XPathException e) {
// no action: error will be caught later
}
}
return overrideExtensionFunction;
}
public void index(ComponentDeclaration decl, PrincipalStylesheetModule top) throws XPathException {
//getSkeletonCompiledFunction();
getCompiledFunction();
top.indexFunction(decl);
}
/**
* Notify all references to this function of the data type.
*
* @throws XPathException
*/
public void fixupReferences() throws XPathException {
// for (UserFunctionReference reference : references) {
// if (reference instanceof UserFunctionCall) {
// ((UserFunctionCall) reference).setStaticType(resultType);
// }
// }
super.fixupReferences();
}
public void validate(ComponentDeclaration decl) throws XPathException {
stackFrameMap = getConfiguration().makeSlotManager();
// check the element is at the top level of the stylesheet
checkTopLevel("XTSE0010", true);
int arity = getNumberOfArguments();
// if (compiledFunction != null) {
// completeCompiledFunction();
// }
if (arity == 0 && streamability != FunctionStreamability.UNCLASSIFIED) {
compileError("A function with no arguments must have streamability=unclassified", "XTSE3155");
}
}
/**
* Compile the function definition to create an executable representation
* The compileDeclaration() method has the side-effect of binding
* all references to the function to the executable representation
* (a UserFunction object)
*
* @throws XPathException
*/
public void compileDeclaration(Compilation compilation, ComponentDeclaration decl) throws XPathException {
Expression exp = compileSequenceConstructor(compilation, decl, false);
if (exp == null) {
exp = Literal.makeEmptySequence();
} else if (Literal.isEmptySequence(exp)) {
// no action
} else {
if (visibility == Visibility.ABSTRACT) {
compileError("A function defined with visibility='abstract' must have no body");
}
exp = exp.simplify();
}
UserFunction fn = getCompiledFunction();
fn.setBody(exp);
fn.setStackFrameMap(stackFrameMap);
bindParameterDefinitions(fn);
fn.setRetainedStaticContext(makeRetainedStaticContext());
if (memoFunction && !fn.isMemoFunction()) {
compileWarning("Memo functions are not available in Saxon-HE: saxon:memo-function attribute ignored",
SaxonErrorCode.SXWN9011);
}
Component overridden = getOverriddenComponent();
if (overridden != null) {
checkCompatibility(overridden);
}
}
public void optimize(ComponentDeclaration declaration) throws XPathException {
Expression exp = compiledFunction.getBody();
ExpressionTool.resetPropertiesWithinSubtree(exp);
ExpressionVisitor visitor = makeExpressionVisitor();
Expression exp2 = exp;
Optimizer opt = getConfiguration().obtainOptimizer();
try {
if (opt.getOptimizationLevel() != Optimizer.NO_OPTIMIZATION) {
exp2 = exp.optimize(visitor, ContextItemStaticInfo.ABSENT);
}
} catch (XPathException err) {
err.maybeSetLocation(getLocation());
compileError(err);
}
// Try to extract new global variables from the body of the function
if (opt.getOptimizationLevel() != Optimizer.NO_OPTIMIZATION) {
Expression exp3 = opt.promoteExpressionsToGlobal(exp2, getCompilation().getPrincipalStylesheetModule(), visitor);
if (exp3 != null) {
exp2 = exp3.optimize(visitor, ContextItemStaticInfo.DEFAULT);
}
}
// Add trace wrapper code if required
exp2 = makeTraceInstruction(this, exp2);
allocateLocalSlots(exp2);
if (exp2 != exp) {
compiledFunction.setBody(exp2);
}
int tailCalls = ExpressionTool.markTailFunctionCalls(exp2, getObjectName(), getNumberOfArguments());
if (tailCalls != 0) {
compiledFunction.setTailRecursive(tailCalls > 0, tailCalls > 1);
compiledFunction.setBody(new TailCallLoop(compiledFunction, compiledFunction.getBody()));
}
compiledFunction.computeEvaluationMode();
if (isExplaining()) {
exp2.explain(getConfiguration().getLogger());
}
}
/**
* Generate byte code if appropriate
*
* @param opt the optimizer
* @throws net.sf.saxon.trans.XPathException
* if bytecode generation fails
*/
public void generateByteCode(Optimizer opt) throws XPathException {
// Generate byte code if appropriate
if (getCompilation().getCompilerInfo().isGenerateByteCode()) {
try {
Expression cbody = opt.compileToByteCode(compiledFunction.getBody(), nameAtt,
Expression.PROCESS_METHOD | Expression.ITERATE_METHOD);
if (cbody != null) {
compiledFunction.setBody(cbody);
}
} catch (Exception e) {
System.err.println("Failed while compiling function " + nameAtt);
e.printStackTrace();
throw new XPathException(e);
}
}
}
/**
* Get associated stack frame details.
* @return the associated SlotManager object
*/
public SlotManager getSlotManager() {
return stackFrameMap;
}
/**
* Get the type of value returned by this function
*
* @return the declared result type, or the inferred result type
* if this is more precise
*/
public SequenceType getResultType() {
if (resultType == null) {
// may be handling a forwards reference - see hof-038
String asAtt = getAttributeValue("", "as");
if (asAtt != null) {
try {
resultType = makeSequenceType(asAtt);
} catch (XPathException err) {
// the error will be reported when we get round to processing the function declaration
}
}
}
return resultType == null ? SequenceType.ANY_SEQUENCE : resultType;
}
/**
* Get the number of arguments declared by this function (that is, its arity).
*
* @return the arity of the function
*/
public int getNumberOfArguments() {
if (numberOfArguments == -1) {
numberOfArguments = 0;
AxisIterator kids = iterateAxis(AxisInfo.CHILD);
while (true) {
Item child = kids.next();
if (child instanceof XSLLocalParam) {
numberOfArguments++;
} else {
return numberOfArguments;
}
}
}
return numberOfArguments;
}
/**
* Set the definitions of the parameters in the compiled function, as an array.
*
* @param fn the compiled object representing the user-written function
*/
public void setParameterDefinitions(UserFunction fn) {
UserFunctionParameter[] params = new UserFunctionParameter[getNumberOfArguments()];
fn.setParameterDefinitions(params);
int count = 0;
AxisIterator kids = iterateAxis(AxisInfo.CHILD);
while (true) {
NodeInfo node = kids.next();
if (node == null) {
return;
}
if (node instanceof XSLLocalParam) {
UserFunctionParameter param = new UserFunctionParameter();
params[count++] = param;
param.setRequiredType(((XSLLocalParam) node).getRequiredType());
param.setVariableQName(((XSLLocalParam) node).getVariableQName());
param.setSlotNumber(((XSLLocalParam) node).getSlotNumber());
} else {
break;
}
}
}
public void bindParameterDefinitions(UserFunction fn) {
UserFunctionParameter[] params = fn.getParameterDefinitions();
int count = 0;
AxisIterator kids = iterateAxis(AxisInfo.CHILD);
while (true) {
NodeInfo node = kids.next();
if (node == null) {
return;
}
if (node instanceof XSLLocalParam) {
UserFunctionParameter param = params[count++];
param.setRequiredType(((XSLLocalParam) node).getRequiredType());
param.setVariableQName(((XSLLocalParam) node).getVariableQName());
param.setSlotNumber(((XSLLocalParam) node).getSlotNumber());
((XSLLocalParam) node).getSourceBinding().fixupBinding(param);
// int refs = ExpressionTool.getReferenceCount(fn.getBody(), param, false);
// param.setReferenceCount(refs);
}
}
}
/**
* Get the argument types
*
* @return the declared types of the arguments
*/
public SequenceType[] getArgumentTypes() {
SequenceType[] types = new SequenceType[getNumberOfArguments()];
int count = 0;
AxisIterator kids = iterateAxis(AxisInfo.CHILD);
while (true) {
NodeInfo node = kids.next();
if (node == null) {
return types;
}
if (node instanceof XSLLocalParam) {
types[count++] = ((XSLLocalParam) node).getRequiredType();
}
}
}
/**
* Get the compiled function
*
* @return the object representing the compiled user-written function
*/
public UserFunction getCompiledFunction() {
if (compiledFunction == null) {
try {
prepareAttributes();
UserFunction fn = getConfiguration().newUserFunction(memoFunction);
fn.setPackageData(getCompilation().getPackageData());
fn.setFunctionName(getObjectName());
setParameterDefinitions(fn);
fn.setResultType(getResultType());
fn.setLineNumber(getLineNumber());
fn.setSystemId(getSystemId());
fn.makeDeclaringComponent(visibility, getContainingPackage());
fn.setDeclaredVisibility(getDeclaredVisibility());
fn.setDeclaredStreamability(streamability);
fn.setDeterminism(determinism);
compiledFunction = fn;
} catch (XPathException err) {
return null;
}
}
return compiledFunction;
}
/**
* Get the type of construct. This will be a constant in
* class {@link LocationKind}. This method is part of the
* {@link net.sf.saxon.trace.InstructionInfo} interface
*/
public int getConstructType() {
return StandardNames.XSL_FUNCTION;
}
}
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