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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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.functions.registry;
import net.sf.saxon.functions.hof.AtomicConstructorFunction;
import net.sf.saxon.Configuration;
import net.sf.saxon.expr.*;
import net.sf.saxon.functions.CallableFunction;
import net.sf.saxon.functions.FunctionLibrary;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.Function;
import net.sf.saxon.om.NamespaceResolver;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.trans.SymbolicName;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.*;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.EmptySequence;
import net.sf.saxon.value.SequenceType;
import java.util.List;
/**
* The ConstructorFunctionLibrary represents the collection of constructor functions for atomic types. These
* are provided for the built-in types such as xs:integer and xs:date, and also for user-defined atomic types.
*/
public class ConstructorFunctionLibrary implements FunctionLibrary {
private final Configuration config;
/**
* Create a SystemFunctionLibrary
*
* @param config the Configuration
*/
public ConstructorFunctionLibrary(Configuration config) {
this.config = config;
}
/**
* Test whether a function with a given name and arity is available; if so, return a function
* item that can be dynamically called.
* This supports the function-lookup() function in XPath 3.0.
*
* @param functionName the qualified name of the function being called
* @param staticContext the static context to be used by the function, in the event that
* it is a system function with dependencies on the static context
* @return if a function of this name and arity is available for calling, then a corresponding
* function item; or null if the function does not exist
* @throws net.sf.saxon.trans.XPathException
* in the event of certain errors, for example attempting to get a function
* that is private
*/
@Override
public Function getFunctionItem(SymbolicName.F functionName, StaticContext staticContext) throws XPathException {
if (functionName.getArity() != 1) {
return null;
}
final String uri = functionName.getComponentName().getURI();
final String localName = functionName.getComponentName().getLocalPart();
final SchemaType type = config.getSchemaType(new StructuredQName("", uri, localName));
if (type == null || type.isComplexType()) {
return null;
}
final NamespaceResolver resolver = ((SimpleType) type).isNamespaceSensitive() ? staticContext.getNamespaceResolver() : null;
if (type instanceof AtomicType) {
return new AtomicConstructorFunction((AtomicType) type, resolver);
} else if (type instanceof ListType) {
return new ListConstructorFunction((ListType)type, resolver, true);
} else {
Callable callable = new CallableDelegate((context, arguments) -> {
AtomicValue value = (AtomicValue) arguments[0].head();
if (value == null) {
return EmptySequence.getInstance();
}
return UnionConstructorFunction.cast(value, (UnionType) type, resolver, context.getConfiguration().getConversionRules());
});
SequenceType returnType = ((UnionType) type).getResultTypeOfCast();
return new CallableFunction(1, callable,
new SpecificFunctionType(new SequenceType[]{SequenceType.OPTIONAL_ATOMIC}, returnType));
}
}
@Override
public boolean isAvailable(SymbolicName.F functionName, int languageLevel) {
if (functionName.getArity() != 1) {
return false;
}
final String uri = functionName.getComponentName().getURI();
final String localName = functionName.getComponentName().getLocalPart();
final SchemaType type = config.getSchemaType(new StructuredQName("", uri, localName));
if (type == null || type.isComplexType()) {
return false;
}
if (type.isAtomicType() && ((AtomicType) type).isAbstract()) {
return false;
}
return type != AnySimpleType.getInstance();
}
/**
* Bind a static function call, given the URI and local parts of the function name,
* and the list of expressions supplied as arguments. This method is called at compile
* time.
*
* @param functionName The QName of the function
* @param arguments The expressions supplied statically in the function call. The intention is
* that the static type of the arguments (obtainable via getItemType() and getCardinality() may
* be used as part of the binding algorithm.
* @param env The static context
* @param reasons If no matching function is found by the function library, it may add
* a diagnostic explanation to this list explaining why none of the available
* functions could be used.
* @return An object representing the constructor function to be called, if one is found;
* null if no constructor function was found matching the required name and arity.
*/
@Override
public Expression bind(SymbolicName.F functionName, Expression[] arguments, StaticContext env, List reasons) {
final String uri = functionName.getComponentName().getURI();
final String localName = functionName.getComponentName().getLocalPart();
boolean builtInNamespace = uri.equals(NamespaceConstant.SCHEMA);
if (builtInNamespace) {
// it's a constructor function: treat it as shorthand for a cast expression
if (functionName.getArity() != 1) {
reasons.add("A constructor function must have exactly one argument");
return null;
}
SimpleType type = Type.getBuiltInSimpleType(uri, localName);
if (type != null) {
if (type.isAtomicType()) {
if (((AtomicType) type).isAbstract()) {
reasons.add("Abstract type used in constructor function: {" + uri + '}' + localName);
return null;
} else {
CastExpression cast = new CastExpression(arguments[0], (AtomicType) type, true);
if (arguments[0] instanceof StringLiteral) {
cast.setOperandIsStringLiteral(true);
}
return cast;
}
} else if (type.isUnionType()) {
NamespaceResolver resolver = env.getNamespaceResolver();
UnionConstructorFunction ucf = new UnionConstructorFunction((UnionType) type, resolver, true);
return new StaticFunctionCall(ucf, arguments);
} else {
NamespaceResolver resolver = env.getNamespaceResolver();
try {
ListConstructorFunction lcf = new ListConstructorFunction((ListType)type, resolver, true);
return new StaticFunctionCall(lcf, arguments);
} catch (MissingComponentException e) {
reasons.add("Missing schema component: " + e.getMessage());
return null;
}
}
} else {
reasons.add("Unknown constructor function: {" + uri + '}' + localName);
return null;
}
}
// Now see if it's a constructor function for a user-defined type
if (arguments.length == 1) {
SchemaType st = config.getSchemaType(new StructuredQName("", uri, localName));
if (st instanceof SimpleType) {
if (st instanceof AtomicType) {
return new CastExpression(arguments[0], (AtomicType) st, true);
} else if (st instanceof ListType && env.getXPathVersion() >= 30) {
NamespaceResolver resolver = env.getNamespaceResolver();
try {
ListConstructorFunction lcf = new ListConstructorFunction((ListType) st, resolver, true);
return new StaticFunctionCall(lcf, arguments);
} catch (MissingComponentException e) {
reasons.add("Missing schema component: " + e.getMessage());
return null;
}
} else if (((SimpleType) st).isUnionType() && env.getXPathVersion() >= 30) {
NamespaceResolver resolver = env.getNamespaceResolver();
UnionConstructorFunction ucf = new UnionConstructorFunction((UnionType) st, resolver, true);
return new StaticFunctionCall(ucf, arguments);
}
}
}
return null;
}
/**
* This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows
* new functions to be added, then additions to this copy will not affect the original, or
* vice versa.
*
* @return a copy of this function library. This must be an instance of the original class.
*/
@Override
public FunctionLibrary copy() {
return this;
}
}