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An OSGi bundle for Saxon-HE
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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.expr.parser.*;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.*;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.tree.iter.AxisIterator;
import net.sf.saxon.tree.util.FastStringBuffer;
import net.sf.saxon.type.*;
import net.sf.saxon.value.Cardinality;
import net.sf.saxon.z.IntHashSet;
import net.sf.saxon.z.IntIterator;
import net.sf.saxon.z.IntSet;
import java.util.Iterator;
import java.util.List;
/**
* An AxisExpression is always obtained by simplifying a PathExpression.
* It represents a PathExpression that starts either at the context node, and uses
* a simple node-test with no filters. For example "*", "title", "./item",
* "@*", or "ancestor::chapter*".
*
* An AxisExpression delivers nodes in axis order (not in document order).
* To get nodes in document order, in the case of a reverse axis, the expression
* should be wrapped in a call on reverse().
*/
public final class AxisExpression extends Expression {
private byte axis;
/*@Nullable*/
private NodeTest test;
/*@Nullable*/
private ItemType itemType = null;
private ItemType contextItemType = null;
private int computedCardinality = -1;
private boolean doneWarnings = false;
private boolean contextMaybeUndefined = true;
/**
* Constructor for an AxisExpression whose origin is the context item
*
* @param axis The axis to be used in this AxisExpression: relevant constants are defined
* in class {@link net.sf.saxon.om.AxisInfo}.
* @param nodeTest The conditions to be satisfied by selected nodes. May be null,
* indicating that any node on the axis is acceptable
* @see net.sf.saxon.om.AxisInfo
*/
public AxisExpression(byte axis, /*@Nullable*/ NodeTest nodeTest) {
this.axis = axis;
this.test = nodeTest;
}
/**
* Get a name identifying the kind of expression, in terms meaningful to a user.
*
* @return a name identifying the kind of expression, in terms meaningful to a user.
* The name will always be in the form of a lexical XML QName, and should match the name used
* in explain() output displaying the expression.
*/
public String getExpressionName() {
return "axisStep";
}
/**
* Simplify an expression
*
* @param visitor an expression visitor
* @return the simplified expression
*/
/*@NotNull*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
Expression e2 = super.simplify(visitor);
if (e2 != this) {
return e2;
}
if (axis == AxisInfo.PARENT && (test == null || test instanceof AnyNodeTest)) {
ParentNodeExpression p = new ParentNodeExpression();
ExpressionTool.copyLocationInfo(this, p);
return p;
}
return this;
}
/**
* Type-check the expression
*/
/*@NotNull*/
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException {
if (contextItemType == null) {
XPathException err = new XPathException("Axis step " + toString(visitor.getConfiguration().getNamePool()) +
" cannot be used here: the context item is absent");
err.setIsTypeError(true);
err.setErrorCode("XPDY0002");
err.setLocator(this);
throw err;
} else {
contextMaybeUndefined = contextItemType.contextMaybeUndefined;
}
Configuration config = visitor.getConfiguration();
TypeHierarchy th = config.getTypeHierarchy();
int relation = th.relationship(contextItemType.itemType, AnyNodeTest.getInstance());
if (relation == TypeHierarchy.DISJOINT) {
XPathException err = new XPathException("Axis step " + toString(visitor.getConfiguration().getNamePool()) +
" cannot be used here: the context item is not a node");
err.setIsTypeError(true);
err.setErrorCode("XPTY0020");
err.setLocator(this);
throw err;
} else if (relation == TypeHierarchy.OVERLAPS || relation == TypeHierarchy.SUBSUMES) {
// need to insert a dynamic check of the context item type
ContextItemExpression exp = new ContextItemExpression();
ExpressionTool.copyLocationInfo(this, exp);
RoleLocator role = new RoleLocator(RoleLocator.AXIS_STEP, AxisInfo.axisName[axis], 0);
role.setErrorCode("XPTY0020");
ItemChecker checker = new ItemChecker(exp, AnyNodeTest.getInstance(), role);
ExpressionTool.copyLocationInfo(this, checker);
SimpleStepExpression step = new SimpleStepExpression(checker, this);
ExpressionTool.copyLocationInfo(this, step);
return step;
}
StaticContext env = visitor.getStaticContext();
if (this.contextItemType == contextItemType && doneWarnings) {
return this;
}
this.contextItemType = contextItemType.itemType;
doneWarnings = true;
ItemType contextType = this.contextItemType;
if (contextType instanceof NodeTest) {
int origin = contextType.getPrimitiveType();
if (origin != Type.NODE) {
if (AxisInfo.isAlwaysEmpty(axis, origin)) {
env.issueWarning("The " + AxisInfo.axisName[axis] + " axis starting at " +
(origin == Type.ELEMENT || origin == Type.ATTRIBUTE ? "an " : "a ") +
NodeKindTest.nodeKindName(origin) + " node will never select anything",
this);
return Literal.makeEmptySequence();
}
}
if (test != null) {
int kind = test.getPrimitiveType();
if (kind != Type.NODE) {
if (!AxisInfo.containsNodeKind(axis, kind)) {
env.issueWarning("The " + AxisInfo.axisName[axis] + " axis will never select any " +
NodeKindTest.nodeKindName(kind) + " nodes",
this);
return Literal.makeEmptySequence();
}
}
if (axis == AxisInfo.SELF && kind != Type.NODE && origin != Type.NODE && kind != origin) {
env.issueWarning("The self axis will never select any " +
NodeKindTest.nodeKindName(kind) +
" nodes when starting at " +
(origin == Type.ELEMENT || origin == Type.ATTRIBUTE ? "an " : "a ") +
NodeKindTest.nodeKindName(origin) + " node", this);
return Literal.makeEmptySequence();
}
if (axis == AxisInfo.SELF) {
itemType = new CombinedNodeTest(test, Token.INTERSECT, (NodeTest) contextType);
}
// If the content type of the context item is known, see whether the node test can select anything
if (contextType instanceof DocumentNodeTest && kind == Type.ELEMENT) {
NodeTest elementTest = ((DocumentNodeTest) contextType).getElementTest();
IntSet outermostElementNames = elementTest.getRequiredNodeNames();
if (outermostElementNames != null) {
IntSet selectedElementNames = test.getRequiredNodeNames();
if (selectedElementNames != null) {
if (axis == AxisInfo.CHILD) {
// check that the name appearing in the step is one of the names allowed by the nodetest
if (selectedElementNames.intersect(outermostElementNames).isEmpty()) {
env.issueWarning("Starting at a document node, the step is selecting an element whose name " +
"is not among the names of child elements permitted for this document node type", this);
return Literal.makeEmptySequence();
}
if (env.isSchemaAware() &&
elementTest instanceof SchemaNodeTest &&
outermostElementNames.size() == 1) {
IntIterator oeni = outermostElementNames.iterator();
int outermostElementName = (oeni.hasNext() ? oeni.next() : -1);
SchemaDeclaration decl = config.getElementDeclaration(outermostElementName);
if (decl == null) {
env.issueWarning("Element " + config.getNamePool().getDisplayName(outermostElementName) +
" is not declared in the schema", this);
itemType = elementTest;
} else {
SchemaType contentType = decl.getType();
itemType = new CombinedNodeTest(
elementTest, Token.INTERSECT,
new ContentTypeTest(Type.ELEMENT, contentType, config, true));
}
} else {
itemType = elementTest;
}
return this;
} else if (axis == AxisInfo.DESCENDANT) {
// check that the name appearing in the step is one of the names allowed by the nodetest
boolean canMatchOutermost = !selectedElementNames.intersect(outermostElementNames).isEmpty();
if (!canMatchOutermost) {
// The expression /descendant::x starting at the document node doesn't match the outermost
// element, so replace it by child::*/descendant::x, and check that
Expression path = ExpressionTool.makePathExpression(new AxisExpression(AxisInfo.CHILD, elementTest), new AxisExpression(AxisInfo.DESCENDANT, test), false);
ExpressionTool.copyLocationInfo(this, path);
return path.typeCheck(visitor, contextItemType);
}
}
}
}
}
SchemaType contentType = ((NodeTest) contextType).getContentType();
if (contentType == AnyType.getInstance()) {
// fast exit in non-schema-aware case
return this;
}
int targetfp = test.getFingerprint();
if (contentType.isSimpleType()) {
if ((axis == AxisInfo.CHILD || axis == AxisInfo.DESCENDANT || axis == AxisInfo.DESCENDANT_OR_SELF) &&
(kind == Type.ELEMENT || kind == Type.ATTRIBUTE || kind == Type.DOCUMENT)) {
env.issueWarning("The " + AxisInfo.axisName[axis] + " axis will never select any " +
NodeKindTest.nodeKindName(kind) +
" nodes when starting at " +
(origin == Type.ATTRIBUTE ? "an attribute node" : getStartingNodeDescription(contentType)),
this);
} else if (axis == AxisInfo.CHILD && kind == Type.TEXT &&
(visitor.getParentExpression() instanceof Atomizer)) {
env.issueWarning("Selecting the text nodes of an element with simple content may give the " +
"wrong answer in the presence of comments or processing instructions. It is usually " +
"better to omit the '/text()' step", this);
} else if (axis == AxisInfo.ATTRIBUTE) {
Iterator extensions = config.getExtensionsOfType(contentType);
boolean found = false;
if (targetfp == -1) {
while (extensions.hasNext()) {
ComplexType extension = (ComplexType) extensions.next();
if (extension.allowsAttributes()) {
found = true;
break;
}
}
} else {
while (extensions.hasNext()) {
ComplexType extension = (ComplexType) extensions.next();
try {
if (extension.getAttributeUseType(targetfp) != null) {
found = true;
break;
}
} catch (SchemaException e) {
// ignore the error
}
}
}
if (!found) {
env.issueWarning("The " + AxisInfo.axisName[axis] + " axis will never select " +
(targetfp == -1 ?
"any attribute nodes" :
"an attribute node named " + getDiagnosticName(targetfp, env)) +
" when starting at " + getStartingNodeDescription(contentType), this);
// Despite the warning, leave the expression unchanged. This is because
// we don't necessarily know about all extended types at compile time:
// in particular, we don't seal the XML Schema namespace to block extensions
// of built-in types
}
}
} else if (((ComplexType) contentType).isSimpleContent() &&
(axis == AxisInfo.CHILD || axis == AxisInfo.DESCENDANT || axis == AxisInfo.DESCENDANT_OR_SELF) &&
(kind == Type.ELEMENT || kind == Type.DOCUMENT)) {
// We don't need to consider extended types here, because a type with complex content
// can never be defined as an extension of a type with simple content
env.issueWarning("The " + AxisInfo.axisName[axis] + " axis will never select any " +
NodeKindTest.nodeKindName(kind) +
" nodes when starting at " +
getStartingNodeDescription(contentType) +
", as this type requires simple content", this);
return Literal.makeEmptySequence();
} else if (((ComplexType) contentType).isEmptyContent() &&
(axis == AxisInfo.CHILD || axis == AxisInfo.DESCENDANT || axis == AxisInfo.DESCENDANT_OR_SELF)) {
for (Iterator iter = config.getExtensionsOfType(contentType); iter.hasNext(); ) {
ComplexType extension = (ComplexType) iter.next();
if (!extension.isEmptyContent()) {
return this;
}
}
env.issueWarning("The " + AxisInfo.axisName[axis] + " axis will never select any" +
" nodes when starting at " +
getStartingNodeDescription(contentType) +
", as this type requires empty content", this);
return Literal.makeEmptySequence();
} else if (axis == AxisInfo.ATTRIBUTE) {
if (targetfp == -1) {
if (!((ComplexType) contentType).allowsAttributes()) {
env.issueWarning("The complex type " + contentType.getDescription() +
" allows no attributes other than the standard attributes in the xsi namespace", this);
}
} else {
try {
SchemaType schemaType;
if (targetfp == StandardNames.XSI_TYPE) {
schemaType = BuiltInAtomicType.QNAME;
} else if (targetfp == StandardNames.XSI_SCHEMA_LOCATION) {
schemaType = BuiltInListType.ANY_URIS;
} else if (targetfp == StandardNames.XSI_NO_NAMESPACE_SCHEMA_LOCATION) {
schemaType = BuiltInAtomicType.ANY_URI;
} else if (targetfp == StandardNames.XSI_NIL) {
schemaType = BuiltInAtomicType.BOOLEAN;
} else {
schemaType = ((ComplexType) contentType).getAttributeUseType(targetfp);
}
if (schemaType == null) {
env.issueWarning("The complex type " + contentType.getDescription() +
" does not allow an attribute named " + getDiagnosticName(targetfp, env), this);
return Literal.makeEmptySequence();
} else {
itemType = new CombinedNodeTest(
test,
Token.INTERSECT,
new ContentTypeTest(Type.ATTRIBUTE, schemaType, env.getConfiguration(), false));
}
} catch (SchemaException e) {
// ignore the exception
}
}
} else if (axis == AxisInfo.CHILD && kind == Type.ELEMENT) {
try {
int childElement = targetfp;
if (targetfp == -1) {
// select="child::*"
if (((ComplexType) contentType).containsElementWildcard()) {
return this;
}
IntHashSet children = new IntHashSet();
((ComplexType) contentType).gatherAllPermittedChildren(children, false);
if (children.isEmpty()) {
env.issueWarning("The complex type " + contentType.getDescription() +
" does not allow children", this);
return Literal.makeEmptySequence();
}
// if (children.contains(-1)) {
// return this;
// }
if (children.size() == 1) {
IntIterator iter = children.iterator();
if (iter.hasNext()) {
childElement = iter.next();
}
} else {
return this;
}
}
SchemaType schemaType = ((ComplexType) contentType).getElementParticleType(childElement, true);
if (schemaType == null) {
env.issueWarning("The complex type " + contentType.getDescription() +
" does not allow a child element named " + getDiagnosticName(childElement, env), this);
return Literal.makeEmptySequence();
} else {
itemType = new CombinedNodeTest(
test,
Token.INTERSECT,
new ContentTypeTest(Type.ELEMENT, schemaType, env.getConfiguration(), true));
computedCardinality = ((ComplexType) contentType).getElementParticleCardinality(childElement, true);
visitor.resetStaticProperties();
if (computedCardinality == StaticProperty.ALLOWS_ZERO) {
// this shouldn't happen, because we've already checked for this a different way.
// but it's worth being safe (there was a bug involving an incorrect inference here)
env.issueWarning("The complex type " + contentType.getDescription() +
" appears not to allow a child element named " + getDiagnosticName(childElement, env), this);
return Literal.makeEmptySequence();
}
if (!Cardinality.allowsMany(computedCardinality)) {
// if there can be at most one child of this name, create a FirstItemExpression
// to stop the search after the first one is found
return FirstItemExpression.makeFirstItemExpression(this);
}
}
} catch (SchemaException e) {
// ignore the exception
}
} else if (axis == AxisInfo.DESCENDANT && kind == Type.ELEMENT && targetfp != -1) {
// when searching for a specific element on the descendant axis, try to produce a more
// specific path that avoids searching branches of the tree where the element cannot occur
try {
IntHashSet descendants = new IntHashSet();
((ComplexType) contentType).gatherAllPermittedDescendants(descendants);
if (descendants.contains(-1)) {
return this;
}
if (descendants.contains(targetfp)) {
IntHashSet children = new IntHashSet();
((ComplexType) contentType).gatherAllPermittedChildren(children, false);
IntHashSet usefulChildren = new IntHashSet();
boolean considerSelf = false;
boolean considerDescendants = false;
for (IntIterator child = children.iterator(); child.hasNext(); ) {
int c = child.next();
if (c == targetfp) {
usefulChildren.add(c);
considerSelf = true;
}
SchemaType st = ((ComplexType) contentType).getElementParticleType(c, true);
if (st == null) {
throw new AssertionError("Can't find type for child element " + c);
}
if (st instanceof ComplexType) {
IntHashSet subDescendants = new IntHashSet();
((ComplexType) st).gatherAllPermittedDescendants(subDescendants);
if (subDescendants.contains(targetfp)) {
usefulChildren.add(c);
considerDescendants = true;
}
}
}
itemType = test;
if (considerDescendants) {
SchemaType st = ((ComplexType) contentType).getDescendantElementType(targetfp);
if (st != AnyType.getInstance()) {
itemType = new CombinedNodeTest(
test, Token.INTERSECT,
new ContentTypeTest(Type.ELEMENT, st, config, true));
}
//return this;
}
if (usefulChildren.size() < children.size()) {
NodeTest childTest = makeUnionNodeTest(usefulChildren, visitor.getConfiguration().getNamePool());
AxisExpression first = new AxisExpression(AxisInfo.CHILD, childTest);
ExpressionTool.copyLocationInfo(this, first);
byte nextAxis;
if (considerSelf) {
nextAxis = (considerDescendants ? AxisInfo.DESCENDANT_OR_SELF : AxisInfo.SELF);
} else {
nextAxis = AxisInfo.DESCENDANT;
}
AxisExpression next = new AxisExpression(nextAxis, (NodeTest) itemType);
ExpressionTool.copyLocationInfo(this, next);
Expression path = ExpressionTool.makePathExpression(first, next, false);
ExpressionTool.copyLocationInfo(this, path);
return path.typeCheck(visitor, contextItemType);
}
} else {
env.issueWarning("The complex type " + contentType.getDescription() +
" does not allow a descendant element named " + getDiagnosticName(targetfp, env), this);
}
} catch (SchemaException e) {
throw new AssertionError(e);
}
}
}
}
return this;
}
/*
* Get a string representation of a name to use in diagnostics
*/
private static String getDiagnosticName(int fp, StaticContext env) {
NamePool pool = env.getNamePool();
String uri = pool.getURI(fp);
NamespaceResolver resolver = env.getNamespaceResolver();
for (Iterator it = resolver.iteratePrefixes(); it.hasNext(); ) {
String prefix = it.next();
if (uri.equals(resolver.getURIForPrefix(prefix, true))) {
if (prefix.length() == 0) {
return "{" + uri + "}" + pool.getLocalName(fp);
} else {
return prefix + ":" + pool.getLocalName(fp);
}
}
}
return "{" + uri + "}" + pool.getLocalName(fp);
}
private static String getStartingNodeDescription(SchemaType type) {
String s = type.getDescription();
if (s.startsWith("of element")) {
return "a valid element named" + s.substring("of element".length());
} else if (s.startsWith("of attribute")) {
return "a valid attribute named" + s.substring("of attribute".length());
} else {
return "a node with " + (type.isSimpleType() ? "simple" : "complex") + " type " + s;
}
}
/**
* Make a union node test for a set of supplied element fingerprints
*
* @param elements the set of integer element fingerprints to be tested for. Must not
* be empty.
* @param pool the name pool
* @return a NodeTest that returns true if the node is an element whose name is one of the names
* in this set
*/
private NodeTest makeUnionNodeTest(IntHashSet elements, NamePool pool) {
NodeTest test = null;
for (IntIterator iter = elements.iterator(); iter.hasNext(); ) {
int fp = iter.next();
NodeTest nextTest = new NameTest(Type.ELEMENT, fp, pool);
if (test == null) {
test = nextTest;
} else {
test = new CombinedNodeTest(test, Token.UNION, nextTest);
}
}
return test;
}
/**
* Get the static type of the context item for this AxisExpression. May be null if not known.
*
* @return the statically-inferred type, or null if not known
*/
public ItemType getContextItemType() {
return contextItemType;
}
/**
* Perform optimisation of an expression and its subexpressions.
*
* This method is called after all references to functions and variables have been resolved
* to the declaration of the function or variable, and after all type checking has been done.
*
* @param visitor an expression visitor
* @param contextItemType the static type of "." at the point where this expression is invoked.
* The parameter is set to null if it is known statically that the context item will be undefined.
* If the type of the context item is not known statically, the argument is set to
* {@link net.sf.saxon.type.Type#ITEM_TYPE}
* @return the original expression, rewritten if appropriate to optimize execution
*/
// public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) {
// return this;
// }
/**
* Is this expression the same as another expression?
*/
public boolean equals(Object other) {
if (!(other instanceof AxisExpression)) {
return false;
}
if (axis != ((AxisExpression) other).axis) {
return false;
}
if (test == null) {
return ((AxisExpression) other).test == null;
}
return test.toString().equals(((AxisExpression) other).test.toString());
}
/**
* get HashCode for comparing two expressions
*/
public int hashCode() {
// generate an arbitrary hash code that depends on the axis and the node test
int h = 9375162 + axis << 20;
if (test != null) {
h ^= test.getPrimitiveType() << 16;
h ^= test.getFingerprint();
}
return h;
}
/**
* Determine which aspects of the context the expression depends on. The result is
* a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and
* XPathContext.CURRENT_NODE
*/
// public int getIntrinsicDependencies() {
// return StaticProperty.DEPENDS_ON_CONTEXT_ITEM;
// }
/**
* Copy an expression. This makes a deep copy.
*
* @return the copy of the original expression
*/
/*@NotNull*/
public Expression copy() {
AxisExpression a2 = new AxisExpression(axis, test);
a2.itemType = itemType;
a2.contextItemType = contextItemType;
a2.computedCardinality = computedCardinality;
a2.doneWarnings = doneWarnings;
return a2;
}
/**
* 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.
*/
public int computeSpecialProperties() {
return StaticProperty.CONTEXT_DOCUMENT_NODESET |
StaticProperty.SINGLE_DOCUMENT_NODESET |
StaticProperty.NON_CREATIVE |
(AxisInfo.isForwards[axis] ? StaticProperty.ORDERED_NODESET : StaticProperty.REVERSE_DOCUMENT_ORDER) |
(AxisInfo.isPeerAxis[axis] ? StaticProperty.PEER_NODESET : 0) |
(AxisInfo.isSubtreeAxis[axis] ? StaticProperty.SUBTREE_NODESET : 0) |
((axis == AxisInfo.ATTRIBUTE || axis == AxisInfo.NAMESPACE) ? StaticProperty.ATTRIBUTE_NS_NODESET : 0);
}
/**
* Determine the data type of the items returned by this expression
*
* @param th the type hierarchy cache
* @return Type.NODE or a subtype, based on the NodeTest in the axis step, plus
* information about the content type if this is known from schema analysis
*/
/*@NotNull*/
public final ItemType getItemType(TypeHierarchy th) {
if (itemType != null) {
return itemType;
}
int p = AxisInfo.principalNodeType[axis];
switch (p) {
case Type.ATTRIBUTE:
case Type.NAMESPACE:
return NodeKindTest.makeNodeKindTest(p);
default:
if (test == null) {
return AnyNodeTest.getInstance();
} else {
return test;
}
}
}
/**
* Determine the intrinsic dependencies of an expression, that is, those which are not derived
* from the dependencies of its subexpressions. For example, position() has an intrinsic dependency
* on the context position, while (position()+1) does not. The default implementation
* of the method returns 0, indicating "no dependencies".
*
* @return a set of bit-significant flags identifying the "intrinsic"
* dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
*/
@Override
public int getIntrinsicDependencies() {
return StaticProperty.DEPENDS_ON_CONTEXT_ITEM;
}
/**
* Determine the cardinality of the result of this expression
*/
public final int computeCardinality() {
if (computedCardinality != -1) {
// This takes care of the case where cardinality was computed during type checking of the child axis
return computedCardinality;
}
NodeTest originNodeType;
NodeTest nodeTest = test;
if (contextItemType instanceof NodeTest) {
originNodeType = (NodeTest) contextItemType;
} else if (contextItemType instanceof AnyItemType) {
originNodeType = AnyNodeTest.getInstance();
} else {
// context item not a node - we'll report a type error somewhere along the line
return StaticProperty.ALLOWS_ZERO_OR_MORE;
}
if (axis == AxisInfo.ATTRIBUTE && nodeTest instanceof NameTest) {
SchemaType contentType = originNodeType.getContentType();
if (contentType instanceof ComplexType) {
try {
return ((ComplexType) contentType).getAttributeUseCardinality(nodeTest.getFingerprint());
} catch (SchemaException err) {
// shouldn't happen; play safe
return StaticProperty.ALLOWS_ZERO_OR_ONE;
}
} else if (contentType instanceof SimpleType) {
return StaticProperty.EMPTY;
}
return StaticProperty.ALLOWS_ZERO_OR_ONE;
} else if (axis == AxisInfo.DESCENDANT && nodeTest instanceof NameTest && nodeTest.getPrimitiveType() == Type.ELEMENT) {
SchemaType contentType = originNodeType.getContentType();
if (contentType instanceof ComplexType) {
try {
return ((ComplexType) contentType).getDescendantElementCardinality(nodeTest.getFingerprint());
} catch (SchemaException err) {
// shouldn't happen; play safe
return StaticProperty.ALLOWS_ZERO_OR_MORE;
}
} else {
return StaticProperty.EMPTY;
}
} else if (axis == AxisInfo.SELF) {
return StaticProperty.ALLOWS_ZERO_OR_ONE;
} else {
return StaticProperty.ALLOWS_ZERO_OR_MORE;
}
// the parent axis isn't handled by this class
}
/**
* Determine whether the expression can be evaluated without reference to the part of the context
* document outside the subtree rooted at the context node.
*
* @return true if the expression has no dependencies on the context node, or if the only dependencies
* on the context node are downward selections using the self, child, descendant, attribute, and namespace
* axes.
*/
public boolean isSubtreeExpression() {
return AxisInfo.isSubtreeAxis[axis];
}
/**
* Get the axis
*
* @return the axis number, for example {@link net.sf.saxon.om.AxisInfo#CHILD}
*/
public byte getAxis() {
return axis;
}
/**
* Get the NodeTest. Returns null if the AxisExpression can return any node.
*
* @return the node test, or null if all nodes are returned
*/
public NodeTest getNodeTest() {
return test;
}
/**
* 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.
*
* @param pathMap the PathMap to which the expression should be added
* @param pathMapNodeSet
* @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
*/
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) {
if (pathMapNodeSet == null) {
ContextItemExpression cie = new ContextItemExpression();
cie.setContainer(getContainer());
pathMapNodeSet = new PathMap.PathMapNodeSet(pathMap.makeNewRoot(cie));
}
return pathMapNodeSet.createArc(axis, (test == null ? AnyNodeTest.getInstance() : test));
}
/**
* Ask whether there is a possibility that the context item will be undefined
*
* @return true if this is a possibility
*/
public boolean isContextPossiblyUndefined() {
return contextMaybeUndefined;
}
private void addFreeRangingMessage(int axis, List reasons) {
if (reasons != null) {
reasons.add("The " + AxisInfo.axisName[axis] + " axis in a general context is free-ranging (used at line " + getLineNumber() + ")");
}
}
/**
* Convert this expression to an equivalent XSLT pattern
*
* @param config the Saxon configuration
* @param is30 true if this is XSLT 3.0
* @return the equivalent pattern
* @throws net.sf.saxon.trans.XPathException
* if conversion is not possible
*/
@Override
public Pattern toPattern(Configuration config, boolean is30) throws XPathException {
NodeTest test = getNodeTest();
if (test == null) {
test = AnyNodeTest.getInstance();
}
if (test instanceof AnyNodeTest && (axis == AxisInfo.CHILD || axis == AxisInfo.DESCENDANT)) {
test = AnyChildNodeTest.getInstance();
}
int kind = test.getPrimitiveType();
if (axis == AxisInfo.SELF) {
return new ItemTypePattern(test);
} else if (axis == AxisInfo.ATTRIBUTE) {
if (kind == Type.NODE) {
// attribute::node() matches any attribute, and only an attribute
return new ItemTypePattern(NodeKindTest.ATTRIBUTE);
} else if (!AxisInfo.containsNodeKind(axis, kind)) {
// for example, attribute::comment()
return new ItemTypePattern(ErrorType.getInstance());
} else {
return new ItemTypePattern(test);
}
} else if (axis == AxisInfo.CHILD || axis == AxisInfo.DESCENDANT || axis == AxisInfo.DESCENDANT_OR_SELF) {
if (kind != Type.NODE && !AxisInfo.containsNodeKind(axis, kind)) {
return new ItemTypePattern(ErrorType.getInstance());
}
return new ItemTypePattern(test);
} else if (axis == AxisInfo.NAMESPACE) {
if (kind == Type.NODE) {
// namespace::node() matches any attribute, and only an attribute
return new ItemTypePattern(NodeKindTest.NAMESPACE);
} else if (!AxisInfo.containsNodeKind(axis, kind)) {
// for example, namespace::comment()
return new ItemTypePattern(ErrorType.getInstance());
} else {
return new ItemTypePattern(test);
}
} else {
throw new XPathException("Only downwards axes are allowed in a pattern", "XTSE0340");
}
// TODO: //A only matches an A element in a tree rooted at a document
}
/**
* Evaluate the path-expression in a given context to return a NodeSet
*
* @param context the evaluation context
*/
/*@NotNull*/
public AxisIterator iterate(XPathContext context) throws XPathException {
Item item = context.getContextItem();
if (item == null) {
// Might as well do the test anyway, whether or not contextMaybeUndefined is set
NamePool pool;
try {
pool = context.getConfiguration().getNamePool();
} catch (Exception err) {
pool = null;
}
XPathException err = new XPathException("The context item for axis step " +
(pool == null ? toString() : toString(pool)) + " is absent");
err.setErrorCode("XPDY0002");
err.setXPathContext(context);
err.setLocator(this);
err.setIsTypeError(true);
throw err;
}
try {
if (test == null) {
return ((NodeInfo) item).iterateAxis(axis);
} else {
return ((NodeInfo) item).iterateAxis(axis, test);
}
} catch (ClassCastException cce) {
NamePool pool;
try {
pool = context.getConfiguration().getNamePool();
} catch (Exception err) {
pool = null;
}
XPathException err = new XPathException("The context item for axis step " +
(pool == null ? toString() : toString(pool)) + " is not a node");
err.setErrorCode("XPTY0020");
err.setXPathContext(context);
err.setLocator(this);
err.setIsTypeError(true);
throw err;
} catch (UnsupportedOperationException err) {
if (err.getCause() instanceof XPathException) {
XPathException ec = (XPathException) err.getCause();
ec.maybeSetLocation(this);
ec.maybeSetContext(context);
throw ec;
} else {
// the namespace axis is not supported for all tree implementations
dynamicError(err.getMessage(), "XPST0010", context);
return null;
}
}
}
/**
* Iterate the axis from a given starting node, without regard to context
*
* @param origin the starting node
* @return the iterator over the axis
*/
public SequenceIterator iterate(Item origin) throws XPathException {
try {
if (test == null) {
return ((NodeInfo) origin).iterateAxis(axis);
} else {
return ((NodeInfo) origin).iterateAxis(axis, test);
}
} catch (ClassCastException cce) {
XPathException err = new XPathException("The context item for axis step " +
toString() + " is not a node");
err.setErrorCode("XPTY0020");
err.setLocator(this);
err.setIsTypeError(true);
throw err;
}
}
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*/
public void explain(ExpressionPresenter destination) {
destination.startElement("axis");
destination.emitAttribute("name", AxisInfo.axisName[axis]);
destination.emitAttribute("nodeTest", (test == null ? "node()" : test.toString()));
destination.endElement();
}
/**
* Represent the expression as a string. The resulting string will be a valid XPath 3.0 expression
* with no dependencies on namespace bindings other than the binding of the prefix "xs" to the XML Schema
* namespace.
*
* @return the expression as a string in XPath 3.0 syntax
*/
public String toString() {
FastStringBuffer fsb = new FastStringBuffer(FastStringBuffer.TINY);
fsb.append(AxisInfo.axisName[axis]);
fsb.append("::");
fsb.append(test == null ? "node()" : test.toString());
return fsb.toString();
}
/**
* Represent the expression as a string for diagnostics
*
* @param pool the name pool, used for expanding names in the node test
* @return a string representation of the expression
*/
public String toString(NamePool pool) {
FastStringBuffer fsb = new FastStringBuffer(FastStringBuffer.TINY);
fsb.append(AxisInfo.axisName[axis]);
fsb.append("::");
fsb.append(test == null ? "node()" : test.toString());
return fsb.toString();
}
}