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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.expr.instruct;
import net.sf.saxon.expr.*;
import net.sf.saxon.expr.parser.ContextItemStaticInfo;
import net.sf.saxon.expr.parser.ExpressionTool;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.expr.parser.PathMap;
import net.sf.saxon.lib.ParseOptions;
import net.sf.saxon.lib.Validation;
import net.sf.saxon.pattern.MultipleNodeKindTest;
import net.sf.saxon.pattern.NodeKindTest;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.*;
import net.sf.saxon.value.SequenceType;
/**
* An abstract class to act as a common parent for instructions that create element nodes
* and document nodes.
*/
public abstract class ParentNodeConstructor extends Instruction
implements ValidatingInstruction, InstructionWithComplexContent {
private final static OperandRole SAME_FOCUS_CONTENT =
new OperandRole(0, OperandUsage.ABSORPTION, SequenceType.ANY_SEQUENCE);
protected Operand contentOp;
private ParseOptions validationOptions = null;
/**
* Flag set to true if validation=preserve and no schema type supplied for validation; also true
* when validation="strip" if there is no need to physically strip type annotations
*/
protected boolean preservingTypes = true;
/**
* Create a document or element node constructor instruction
*/
public ParentNodeConstructor() {
}
/**
* Get the schema type chosen for validation; null if not defined
*
* @return the type to be used for validation. (For a document constructor, this is the required
* type of the document element)
*/
@Override
public SchemaType getSchemaType() {
return validationOptions == null ? null : validationOptions.getTopLevelType();
}
/**
* Get the validation options
*
* @return the validation options for the content of the constructed node. May be null if no
* validation was requested.
*/
public ParseOptions getValidationOptions() {
return validationOptions;
}
/**
* Set the validation mode for the new document or element node
*
* @param mode the validation mode, for example {@link Validation#STRICT}
* @param schemaType the required type (for validation by type). Null if not
* validating by type
*/
public void setValidationAction(int mode, /*@Nullable*/ SchemaType schemaType) {
preservingTypes = mode == Validation.PRESERVE && schemaType == null;
if (!preservingTypes) {
if (validationOptions == null) {
validationOptions = new ParseOptions();
}
if (schemaType == Untyped.getInstance()) {
validationOptions.setSchemaValidationMode(Validation.SKIP);
} else {
validationOptions.setSchemaValidationMode(mode);
validationOptions.setTopLevelType(schemaType);
}
}
}
/**
* Get the validation mode for this instruction
*
* @return the validation mode, for example {@link Validation#STRICT} or {@link Validation#PRESERVE}
*/
@Override
public int getValidationAction() {
return validationOptions == null ? Validation.PRESERVE : validationOptions.getSchemaValidationMode();
}
/**
* Set that the newly constructed node and everything underneath it will automatically be untyped,
* without any need to physically remove type annotations, even though validation=STRIP is set.
*/
public void setNoNeedToStrip() {
preservingTypes = true;
}
/**
* Set the expression that constructs the content of the element
*
* @param content the content expression
*/
public void setContentExpression(Expression content) {
if (contentOp == null) {
contentOp = new Operand(this, content, SAME_FOCUS_CONTENT);
} else {
contentOp.setChildExpression(content);
}
}
/**
* Get the expression that constructs the content of the element
*
* @return the content expression
*/
@Override
public Expression getContentExpression() {
return contentOp == null ? null : contentOp.getChildExpression();
}
public Operand getContentOperand() {
return contentOp;
}
/**
* Get the cardinality of the sequence returned by evaluating this instruction
*
* @return the static cardinality
*/
@Override
protected int computeCardinality() {
return StaticProperty.EXACTLY_ONE;
}
/*@NotNull*/
@Override
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException {
typeCheckChildren(visitor, contextInfo);
checkContentSequence(visitor.getStaticContext());
return this;
}
/**
* Ask whether common subexpressions found in the operands of this expression can
* be extracted and evaluated outside the expression itself. The result is irrelevant
* in the case of operands evaluated with a different focus, which will never be
* extracted in this way, even if they have no focus dependency.
*
* @return false for this kind of expression
*/
@Override
public boolean allowExtractingCommonSubexpressions() {
return false;
}
/**
* Check that the child instructions don't violate any obvious constraints for this kind of node
*
* @param env the static context
* @throws XPathException if the check fails
*/
protected abstract void checkContentSequence(StaticContext env) throws XPathException;
/*@NotNull*/
@Override
public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException {
optimizeChildren(visitor, contextItemType);
if (!Literal.isEmptySequence(getContentExpression())) {
if (getContentExpression() instanceof Block) {
setContentExpression(((Block) getContentExpression()).mergeAdjacentTextInstructions());
}
// This code removed 25 Aug 2016. We no longer introduce copy operations. But we could go
// further, and try to get rid of more unnecessary copy operations (whether streaming or not...)
// Reinstated 14 Oct 2016
if (visitor.isOptimizeForStreaming()) {
visitor.obtainOptimizer().makeCopyOperationsExplicit(this, contentOp);
}
}
if (visitor.getStaticContext().getPackageData().isSchemaAware()) {
TypeHierarchy th = visitor.getConfiguration().getTypeHierarchy();
if (getValidationAction() == Validation.STRIP) {
if (getContentExpression().hasSpecialProperty(StaticProperty.ALL_NODES_UNTYPED) ||
th.relationship(getContentExpression().getItemType(), MultipleNodeKindTest.DOC_ELEM_ATTR) == Affinity.DISJOINT) {
// No need to strip type annotations if there are none needing to be stripped
setNoNeedToStrip();
}
}
} else {
setValidationAction(Validation.STRIP, null);
setNoNeedToStrip();
}
return this;
}
/**
* Determine whether this instruction creates new nodes.
* This implementation returns true.
*/
@Override
public final boolean mayCreateNewNodes() {
return true;
}
/**
* Ask whether it is guaranteed that every item in the result of this instruction
* is a newly created node
*
* @return true if result of the instruction is always either an empty sequence or
* a sequence consisting entirely of newly created nodes
*/
@Override
public boolean alwaysCreatesNewNodes() {
return true;
}
@Override
public int getCardinality() {
return StaticProperty.EXACTLY_ONE;
}
/**
* 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 pathMapNodeSet representing the points in the source document that are both reachable by this
* expression, and that represent possible results of this 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.
*/
@Override
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) {
PathMap.PathMapNodeSet result = super.addToPathMap(pathMap, pathMapNodeSet);
result.setReturnable(false);
TypeHierarchy th = getConfiguration().getTypeHierarchy();
ItemType type = getItemType();
if (th.relationship(type, NodeKindTest.ELEMENT) != Affinity.DISJOINT ||
th.relationship(type, NodeKindTest.DOCUMENT) != Affinity.DISJOINT) {
result.addDescendants();
}
return new PathMap.PathMapNodeSet(pathMap.makeNewRoot(this));
}
/**
* Determine whether this elementCreator performs validation or strips type annotations
*
* @return false if the instruction performs validation of the constructed output or if it strips
* type annotations, otherwise true
*/
public boolean isPreservingTypes() {
return preservingTypes;
}
public boolean isLocal() {
return ExpressionTool.isLocalConstructor(this);
}
}