net.sf.saxon.expr.UserFunctionCall Maven / Gradle / Ivy
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 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;
import net.sf.saxon.Configuration;
import net.sf.saxon.event.SequenceReceiver;
import net.sf.saxon.evpull.EmptyEventIterator;
import net.sf.saxon.evpull.EventIterator;
import net.sf.saxon.expr.instruct.Executable;
import net.sf.saxon.expr.instruct.UserFunction;
import net.sf.saxon.expr.parser.*;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.Sequence;
import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trace.Location;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.AnyItemType;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.type.TypeHierarchy;
import net.sf.saxon.value.Cardinality;
import net.sf.saxon.value.Closure;
import net.sf.saxon.value.EmptySequence;
import net.sf.saxon.value.SequenceType;
import java.util.ArrayList;
import java.util.List;
/**
* This class represents a call to a user-defined function in the stylesheet or query.
*/
public class UserFunctionCall extends FunctionCall implements UserFunctionReference {
private SequenceType staticType;
private UserFunction function;
private int tailCall = NOT_TAIL_CALL;
/*@Nullable*/ private int[] argumentEvaluationModes = null;
public static final int NOT_TAIL_CALL = 0;
public static final int FOREIGN_TAIL_CALL = 1;
public static final int SELF_TAIL_CALL = 2;
/**
* Create a function call to a user-written function in a query or stylesheet
*/
public UserFunctionCall() {
}
/**
* Set the static type
*
* @param type the static type of the result of the function call
*/
public void setStaticType(SequenceType type) {
staticType = type;
}
/**
* Create the reference to the function to be called
*
* @param compiledFunction the function being called
*/
public void setFunction(UserFunction compiledFunction) {
function = compiledFunction;
}
/**
* Check the function call against the declared function signature
*
* @param compiledFunction the function being called
* @param visitor an expression visitor
*/
public void checkFunctionCall(UserFunction compiledFunction,
ExpressionVisitor visitor) throws XPathException {
Executable executable = visitor.getExecutable();
boolean isXSLT = executable != null && executable.getHostLanguage() == Configuration.XSLT;
int n = compiledFunction.getNumberOfArguments();
for (int i = 0; i < n; i++) {
Object name = compiledFunction.getFunctionName();
if (name == null) {
name = "";
}
RoleLocator role = new RoleLocator(
RoleLocator.FUNCTION, name, i);
if (isXSLT) {
role.setErrorCode("XTTE0790");
}
//role.setSourceLocator(this);
argument[i] = TypeChecker.staticTypeCheck(
argument[i],
compiledFunction.getArgumentType(i),
false,
role, visitor);
}
}
/**
* Get the function that is being called by this function call
*
* @return the function being called
*/
public UserFunction getFunction() {
return function;
}
/**
* Determine whether this is a tail call (not necessarily a recursive tail call)
*
* @return true if this function call is a tail call
*/
public boolean isTailCall() {
return tailCall != NOT_TAIL_CALL;
}
public boolean isRecursiveTailCall() {
return tailCall == SELF_TAIL_CALL;
}
/**
* Method called during the type checking phase
*/
public void checkArguments(/*@NotNull*/ ExpressionVisitor visitor) throws XPathException {
// these checks are now done in setFunction(), at the time when the function
// call is bound to an actual function
}
/**
* Get the qualified of the function being called
*
* @return the qualified name
*/
public final StructuredQName getFunctionName() {
StructuredQName n = super.getFunctionName();
if (n == null) {
return function.getFunctionName();
} else {
return n;
}
}
/**
* Get the evaluation modes that have been determined for each of the arguments
*
* @return an array of integers representing the evaluation modes, one for each argument
*/
public int[] getArgumentEvaluationModes() {
return argumentEvaluationModes;
}
/**
* Pre-evaluate a function at compile time. This version of the method suppresses
* early evaluation by doing nothing.
*
* @param visitor an expression visitor
*/
public Expression preEvaluate(ExpressionVisitor visitor) {
return this;
}
/**
* Determine the data type of the expression, if possible
*
* @param th the type hierarchy cache
* @return Type.ITEM (meaning not known in advance)
*/
/*@NotNull*/
public ItemType getItemType(TypeHierarchy th) {
if (staticType == null) {
// the actual type is not known yet, so we return an approximation
return AnyItemType.getInstance();
} else {
return staticType.getPrimaryType();
}
}
public int getIntrinsicDependencies() {
return StaticProperty.DEPENDS_ON_USER_FUNCTIONS;
}
/**
* Determine whether this is an updating expression as defined in the XQuery update specification
*
* @return true if this is an updating expression
*/
public boolean isUpdatingExpression() {
return function.isUpdating();
}
/**
* Compute the special properties of this expression. These properties are denoted by a bit-significant
* integer, possible values are in class {@link net.sf.saxon.expr.StaticProperty}. The "special" properties are properties
* other than cardinality and dependencies, and most of them relate to properties of node sequences, for
* example whether the nodes are in document order.
*
* @return the special properties, as a bit-significant integer
*/
protected int computeSpecialProperties() {
// Inherit the properties of the function being called if possible. But we have to prevent
// looping when the function is recursive. For safety, we only consider the properties of the
// function body if it contains no further function calls.
if (function == null) {
return super.computeSpecialProperties();
} else {
List calledFunctions = new ArrayList();
ExpressionTool.gatherCalledFunctions(function.getBody(), calledFunctions);
if (calledFunctions.isEmpty()) {
return function.getBody().computeSpecialProperties();
} else {
return super.computeSpecialProperties();
}
}
}
/**
* Copy an expression. This makes a deep copy.
*
* @return the copy of the original expression
*/
/*@NotNull*/
public Expression copy() {
if (function == null) {
// not bound yet, we have no way to register the new copy with the XSLFunction
throw new UnsupportedOperationException("UserFunctionCall.copy()");
}
UserFunctionCall ufc = new UserFunctionCall();
ufc.setFunction(function);
ufc.setStaticType(staticType);
Expression[] a2 = new Expression[argument.length];
for (int i = 0; i < argument.length; i++) {
a2[i] = argument[i].copy();
}
ufc.argument = a2;
if (argumentEvaluationModes != null) {
int[] am2 = new int[argumentEvaluationModes.length];
System.arraycopy(argumentEvaluationModes, 0, am2, 0, am2.length);
ufc.argumentEvaluationModes = am2;
}
return ufc;
}
/**
* Determine the cardinality of the result
*/
public int computeCardinality() {
if (staticType == null) {
// the actual type is not known yet, so we return an approximation
return StaticProperty.ALLOWS_ZERO_OR_MORE;
} else {
return staticType.getCardinality();
}
}
/*@NotNull*/
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException {
Expression e = super.typeCheck(visitor, contextItemType);
if (e != this) {
return e;
}
if (function != null) {
if (function.getFunctionName() == null) {
// This is an inline function item; add type-checking for the argument types and the result type
checkFunctionCall(function, visitor);
Expression body = function.getBody();
body = body.typeCheck(visitor, null);
TypeHierarchy th = visitor.getConfiguration().getTypeHierarchy();
RoleLocator role = new RoleLocator(RoleLocator.FUNCTION_RESULT, "", 0);
body = TypeChecker.staticTypeCheck(body, function.getResultType(th), visitor.getStaticContext().isInBackwardsCompatibleMode(), role, visitor);
function.setBody(body);
}
computeArgumentEvaluationModes();
if (staticType == SequenceType.ANY_SEQUENCE) {
// try to get a better type
staticType = function.getResultType(visitor.getConfiguration().getTypeHierarchy());
}
}
return this;
}
/*@NotNull*/
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException {
Expression e = super.optimize(visitor, contextItemType);
if (e == this && function != null) {
computeArgumentEvaluationModes();
Expression e2 = visitor.getConfiguration().obtainOptimizer().tryInlineFunctionCall(
this, visitor, contextItemType);
if (e2 != this) {
return visitor.optimize(e2, contextItemType);
}
return e2;
}
return e;
}
/**
* Promote this expression if possible
*/
public Expression promote(PromotionOffer offer, Expression parent) throws XPathException {
Expression exp = offer.accept(parent, this);
if (exp != null) {
return exp;
} else {
boolean changed = false;
if (offer.action != PromotionOffer.UNORDERED) {
for (int i = 0; i < argument.length; i++) {
Expression a2 = doPromotion(argument[i], offer);
changed |= (a2 != argument[i]);
argument[i] = a2;
}
}
if (changed && function != null) {
computeArgumentEvaluationModes();
}
return this;
}
}
/**
* Compute the evaluation mode of each argument
*/
public void computeArgumentEvaluationModes() {
argumentEvaluationModes = new int[argument.length];
for (int i = 0; i < argument.length; i++) {
int refs = function.getParameterDefinitions()[i].getReferenceCount();
if (refs == 0) {
// the argument is never referenced, so don't evaluate it
argumentEvaluationModes[i] = ExpressionTool.RETURN_EMPTY_SEQUENCE;
} else if (function.getParameterDefinitions()[i].isIndexedVariable()) {
argumentEvaluationModes[i] = ExpressionTool.MAKE_INDEXED_VARIABLE;
} else if ((argument[i].getDependencies() & StaticProperty.DEPENDS_ON_USER_FUNCTIONS) != 0) {
// if the argument contains a call to a user-defined function, then it might be a recursive call.
// It's better to evaluate it now, rather than waiting until we are on a new stack frame, as
// that can blow the stack if done repeatedly. (See test func42)
argumentEvaluationModes[i] = ExpressionTool.eagerEvaluationMode(argument[i]);
} else {
int m = ExpressionTool.lazyEvaluationMode(argument[i]);
if (m == ExpressionTool.MAKE_CLOSURE && refs > 1) {
m = ExpressionTool.MAKE_MEMO_CLOSURE;
}
argumentEvaluationModes[i] = m;
}
}
}
@Override
public boolean replaceSubExpression(Expression original, Expression replacement) {
boolean found = super.replaceSubExpression(original, replacement);
if (found && argumentEvaluationModes != null) {
computeArgumentEvaluationModes();
}
return found;
}
/**
* Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited
* by an expression in a source tree.
*
* The default implementation of this method assumes that an expression does no navigation other than
* the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the
* same context as the containing expression. The method must be overridden for any expression
* where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression,
* and RootExpression (because they perform navigation), and for the doc(), document(), and collection()
* functions because they create a new navigation root. Implementations also exist for PathExpression and
* FilterExpression because they have subexpressions that are evaluated in a different context from the
* calling expression.
*
* @param pathMap the PathMap to which the expression should be added
* @param pathMapNodeSet the PathMapNodeSet to which the paths embodied in this expression should be added
* @return the pathMapNode representing the focus established by this expression, in the case where this
* expression is the first operand of a path expression or filter expression. For an expression that does
* navigation, it represents the end of the arc in the path map that describes the navigation route. For other
* expressions, it is the same as the input pathMapNode.
*/
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) {
return addExternalFunctionCallToPathMap(pathMap, pathMapNodeSet);
}
/**
* Mark tail-recursive calls on stylesheet functions. This marks the function call as tailRecursive if
* if is a call to the containing function, and in this case it also returns "true" to the caller to indicate
* that a tail call was found.
*/
public int markTailFunctionCalls(StructuredQName qName, int arity) {
tailCall = (getFunctionName().equals(qName) &&
arity == getNumberOfArguments() ? SELF_TAIL_CALL : FOREIGN_TAIL_CALL);
return tailCall;
}
public int getImplementationMethod() {
if (Cardinality.allowsMany(getCardinality())) {
return ITERATE_METHOD | PROCESS_METHOD;
} else {
return EVALUATE_METHOD;
}
}
/**
* Call the function, returning the value as an item. This method will be used
* only when the cardinality is zero or one. If the function is tail recursive,
* it returns an Object representing the arguments to the next (recursive) call
*/
public Item evaluateItem(XPathContext c) throws XPathException {
return callFunction(c).head();
}
/**
* Call the function, returning an iterator over the results. (But if the function is
* tail recursive, it returns an iterator over the arguments of the recursive call)
*/
/*@NotNull*/
public SequenceIterator iterate(XPathContext c) throws XPathException {
return callFunction(c).iterate();
}
/**
* Evaluate an updating expression, adding the results to a Pending Update List.
* The default implementation of this method, which is used for non-updating expressions,
* throws an UnsupportedOperationException
*
* @param context the XPath dynamic evaluation context
* @param pul the pending update list to which the results should be written
*/
public void evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) throws XPathException {
Sequence[] actualArgs = evaluateArguments(context);
XPathContextMajor c2 = context.newCleanContext();
c2.setOrigin(this);
function.callUpdating(actualArgs, c2, pul);
}
/**
* This is the method that actually does the function call
*
* @param c the dynamic context
* @return the result of the function
* @throws XPathException if dynamic errors occur
*/
private Sequence callFunction(XPathContext c) throws XPathException {
Sequence[] actualArgs = evaluateArguments(c);
if (isTailCall()) {
((XPathContextMajor) c).requestTailCall(function, actualArgs);
return EmptySequence.getInstance();
}
XPathContextMajor c2 = c.newCleanContext();
c2.setOrigin(this);
c2.setTemporaryOutputState(true);
try {
return function.call(c2, actualArgs);
} catch (StackOverflowError err) {
throw new XPathException("Too many nested function calls. May be due to infinite recursion.", this);
}
}
/**
* Process the function call in push mode
*
* @param context the XPath dynamic context
* @throws XPathException
*/
public void process(XPathContext context) throws XPathException {
Sequence[] actualArgs = evaluateArguments(context);
if (isTailCall()) {
((XPathContextMajor) context).requestTailCall(function, actualArgs);
} else {
SequenceReceiver out = context.getReceiver();
XPathContextMajor c2 = context.newCleanContext();
c2.setReceiver(out);
c2.setTemporaryOutputState(true);
c2.setOrigin(this);
function.process(actualArgs, c2);
}
}
/**
* Process the function call in pull mode
*
* @param context the XPath dynamic context
* @throws XPathException
*/
public EventIterator iterateEvents(XPathContext context) throws XPathException {
Sequence[] actualArgs = evaluateArguments(context);
if (isTailCall()) {
((XPathContextMajor) context).requestTailCall(function, actualArgs);
return EmptyEventIterator.getInstance();
} else {
SequenceReceiver out = context.getReceiver();
XPathContextMajor c2 = context.newCleanContext();
c2.setReceiver(out);
c2.setOrigin(this);
return function.iterateEvents(actualArgs, c2);
}
}
public Sequence[] evaluateArguments(XPathContext c) throws XPathException {
int numArgs = argument.length;
Sequence[] actualArgs = new Sequence[numArgs];
if (argumentEvaluationModes == null) {
// should have been done at compile time
computeArgumentEvaluationModes();
}
for (int i = 0; i < numArgs; i++) {
int refs = function.getParameterDefinitions()[i].getReferenceCount();
actualArgs[i] = ExpressionTool.evaluate(argument[i], argumentEvaluationModes[i], c, refs);
if (actualArgs[i] == null) {
actualArgs[i] = EmptySequence.getInstance();
}
// If the argument has come in as a (non-memo) closure but there are multiple references to it,
// then we materialize it in memory now. This shouldn't really happen but it does (tour.xq)
if (refs > 1 && actualArgs[i] instanceof Closure) {
actualArgs[i] = ((Closure) actualArgs[i]).reduce();
}
}
return actualArgs;
}
/**
* Call the function dynamically. For this to be possible, the static arguments of the function call
* must have been set up as {@link SuppliedParameterReference} objects. The actual arguments are placed on the
* callee's stack, and the type conversion takes place "in situ".
*
* @param suppliedArguments the values to be used for the arguments of the function
* @param context the dynamic evaluation context
* @return the result of evaluating the function
*/
public Sequence dynamicCall(Sequence[] suppliedArguments, XPathContext context) throws XPathException {
Sequence[] convertedArgs = new Sequence[suppliedArguments.length];
XPathContextMajor c2 = context.newCleanContext();
c2.setOrigin(this);
c2.setCaller(context);
c2.openStackFrame(suppliedArguments.length);
for (int i = 0; i < suppliedArguments.length; i++) {
c2.setLocalVariable(i, suppliedArguments[i]);
convertedArgs[i] = ExpressionTool.lazyEvaluate(argument[i], c2, 10);
}
XPathContextMajor c3 = c2.newCleanContext();
c3.setOrigin(this);
return function.call(c3, convertedArgs);
}
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*/
public void explain(ExpressionPresenter out) {
out.startElement("functionCall");
if (getFunctionName() != null) {
out.emitAttribute("name", getDisplayName());
out.emitAttribute("tailCall",
((tailCall == NOT_TAIL_CALL ? "false" : (tailCall == SELF_TAIL_CALL ? "self" : "foreign"))));
}
for (int a = 0; a < argument.length; a++) {
argument[a].explain(out);
}
if (getFunctionName() == null) {
out.startElement("body");
function.getBody().explain(out);
out.endElement();
}
out.endElement();
}
public int getConstructType() {
return Location.FUNCTION_CALL;
}
public Object getProperty(String name) {
if (name.equals("target")) {
return function;
}
return super.getProperty(name);
}
public StructuredQName getObjectName() {
return getFunctionName();
}
/**
* Get the line number within the document or module containing a particular location
*
* @param locationId identifier of the location in question (as passed down the Receiver pipeline)
* @return the line number within the document or module.
*/
public int getLineNumber(long locationId) {
return getLineNumber();
}
/**
* Get the URI of the document or module containing a particular location
*
* @param locationId identifier of the location in question (as passed down the Receiver pipeline)
* @return the URI of the document or module.
*/
public String getSystemId(long locationId) {
return getSystemId();
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy