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The XSLT and XQuery Processor
package net.sf.saxon.trans;
import net.sf.saxon.Configuration;
import net.sf.saxon.Controller;
import net.sf.saxon.event.PipelineConfiguration;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.XPathContextMajor;
import net.sf.saxon.expr.instruct.ComponentCode;
import net.sf.saxon.expr.instruct.ParameterSet;
import net.sf.saxon.expr.instruct.TailCall;
import net.sf.saxon.expr.instruct.TemplateRule;
import net.sf.saxon.expr.parser.Location;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.lib.TraceListener;
import net.sf.saxon.lib.TraceListener2;
import net.sf.saxon.om.*;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.tree.iter.LookaheadIterator;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.type.SchemaType;
import net.sf.saxon.type.Type;
import net.sf.saxon.type.Untyped;
import java.util.Set;
/**
* A Mode is a collection of rules; the selection of a rule to apply to a given element
* is determined by a Pattern. A SimpleMode is a mode contained within a single package,
* as opposed to a CompoundMode which can combine rules from several packages
*/
public abstract class Mode extends ComponentCode {
public static final StructuredQName OMNI_MODE =
new StructuredQName("saxon", NamespaceConstant.SAXON, "_omniMode");
public static final StructuredQName UNNAMED_MODE_NAME =
new StructuredQName("xsl", NamespaceConstant.XSLT, "unnamed");
public static final StructuredQName DEFAULT_MODE_NAME =
new StructuredQName("xsl", NamespaceConstant.XSLT, "default");
protected StructuredQName modeName;
private boolean streamable;
private int recoveryPolicy = Configuration.RECOVER_WITH_WARNINGS; // since 9.2 fixed at compile time
public boolean mustBeTyped = false;
public boolean mustBeUntyped = false;
public boolean hasRules = false;
public Mode(StructuredQName modeName) {
this.modeName = modeName;
}
/**
* Get the built-in template rules to be used with this Mode in the case where there is no
* explicit template rule
*
* @return the built-in rule set, defaulting to the TextOnlyCopyRuleSet if no other rule set has
* been supplied
*/
public abstract BuiltInRuleSet getBuiltInRuleSet();
/**
* Determine if this is the unnamed mode
*
* @return true if this is the unnamed mode
*/
public boolean isUnnamedMode() {
return modeName.equals(UNNAMED_MODE_NAME);
}
/**
* Get the name of the mode (for diagnostics only)
*
* @return the mode name. Null for the default (unnamed) mode
*/
public StructuredQName getModeName() {
return modeName;
}
/**
* Get the active component of this mode. For a simple mode this is the mode itself;
* for a compound mode it is the "overriding" part
*/
public abstract SimpleMode getActivePart();
/**
* Get the maximum precedence of the rules in this mode
*/
public abstract int getMaxPrecedence();
/**
* Get the highest rank of the rules in this mode
*
* @return the highest rank
*/
public abstract int getMaxRank();
/**
* Compute a rank for each rule, as a combination of the precedence and priority, to allow
* rapid comparison. This method also checks that there are no conflicts for
* property values in different xsl:mode declarations
*
* @param start the lowest rank to use
* @throws XPathException if an error occurs processing the rules
*/
public abstract void computeRankings(int start) throws XPathException;
/**
* Get a title for the mode: either "Mode mode-name" or "The unnamed mode" as appropriate
*
* @return a title for the mode
*/
public String getModeTitle() {
return isUnnamedMode() ? "The unnamed mode" : "Mode" + getModeName().getDisplayName();
}
@Override
public int getComponentKind() {
return StandardNames.XSL_MODE;
}
@Override
public SymbolicName getSymbolicName() {
return new SymbolicName(StandardNames.XSL_MODE, getModeName());
}
public int getConstructType() {
return StandardNames.XSL_MODE;
}
public StructuredQName getObjectName() {
return getModeName();
}
/**
* Ask whether there are any template rules in this mode
* (a mode could exist merely because it is referenced in apply-templates)
*
* @return true if no template rules exist in this mode
*/
public abstract boolean isEmpty();
/**
* Set the policy for handling recoverable errrors. Note that for some errors the decision can be
* made at run-time, but for the "ambiguous template match" error, the decision is (since 9.2)
* fixed at compile time.
*
* @param policy the recovery policy to be used. The options are {@link Configuration#RECOVER_SILENTLY},
* {@link Configuration#RECOVER_WITH_WARNINGS}, or {@link Configuration#DO_NOT_RECOVER}.
*/
public void setRecoveryPolicy(int policy) {
recoveryPolicy = policy;
}
/**
* Get the policy for handling recoverable errors. Note that for some errors the decision can be
* made at run-time, but for the "ambiguous template match" error, the decision is (since 9.2)
* fixed at compile time.
*
* @return the current policy.
*/
public int getRecoveryPolicy() {
return recoveryPolicy;
}
/**
* Say that this mode is (or is not) streamable
*
* @param streamable true if this mode is a streamable mode
*/
public void setStreamable(boolean streamable) {
this.streamable = streamable;
}
/**
* Ask whether this mode is declared to be streamable
*
* @return true if this mode is declared with the option streamable="yes"
*/
public boolean isDeclaredStreamable() {
return streamable;
}
/**
* Get the "explicit namespaces" matched by this mode. Returns a set containing all the namespaces
* matched by specific template rules in this mode
*
* @param pool the NamePool for the configuration
* @return the set of all namespace URIs of names explicitly matched by rules in this mode
*/
public abstract Set getExplicitNamespaces(NamePool pool);
/**
* Walk over all the rules, applying a specified action to each one.
*
* @param action an action that is to be applied to all the rules in this Mode
* @throws XPathException if an error occurs processing any of the rules
*/
public abstract void processRules(RuleAction action) throws XPathException;
/**
* Make a new XPath context for evaluating patterns if there is any possibility that the
* pattern uses local variables
*
* @param context The existing XPath context
* @return a new XPath context
*/
public XPathContext makeNewContext(XPathContext context) {
XPathContextMajor c2 = context.newContext();
c2.setOrigin(context.getController()); // WHY?
c2.openStackFrame(getStackFrameSlotsNeeded());
return c2;
}
/**
* Expand the context to handle stack frame - this should not be called repeatedly on the same context
*
* @param context The existing XPath context
* @return a new XPath context
*/
public XPathContext makeNewContextIfNeeded(XPathContext context) {
if (getStackFrameSlotsNeeded() > 0) {
context = makeNewContext(context);
}
return context;
}
/**
* Get the rule corresponding to a given item, by finding the best pattern match.
*
* @param item the item to be matched
* @param context the XPath dynamic evaluation context
* @return the best matching rule, if any (otherwise null).
* @throws XPathException if an error occurs matching a pattern
*/
public abstract Rule getRule(Item item, XPathContext context) throws XPathException;
/**
* Get the rule corresponding to a given item, by finding the best Pattern match.
*
* @param item the item to be matched
* @param context the XPath dynamic evaluation context
* @param filter a filter to select which rules should be considered
* @return the best matching rule, if any (otherwise null).
* @throws XPathException if an error occurs
*/
/*@Nullable*/
public abstract Rule getRule(Item item, XPathContext context, SimpleMode.RuleFilter filter) throws XPathException;
/**
* Get the rule corresponding to a given Node, by finding the best Pattern match, subject to a minimum
* and maximum precedence. (This supports xsl:apply-imports)
*
* @param item the item to be matched
* @param min the minimum import precedence
* @param max the maximum import precedence
* @param context the XPath dynamic evaluation context
* @return the Rule registered for that node, if any (otherwise null).
* @throws XPathException if an error occurs evaluating match patterns
*/
public Rule getRule(Item item, final int min, final int max, XPathContext context) throws XPathException {
RuleFilter filter = new RuleFilter() {
public boolean testRule(Rule r) {
int p = r.getPrecedence();
return p >= min && p <= max;
}
};
return getRule(item, context, filter);
}
/**
* Get the rule corresponding to a given Node, by finding the next-best Pattern match
* after the specified object.
*
* @param item the NodeInfo referring to the node to be matched
* @param currentRule the current rule; we are looking for the next match after the current rule
* @param context the XPath dynamic evaluation context
* @return the object (e.g. a NodeHandler) registered for that element, if any (otherwise null).
* @throws XPathException if an error occurs matching a pattern
*/
public Rule getNextMatchRule(Item item, final Rule currentRule, XPathContext context) throws XPathException {
SimpleMode.RuleFilter filter = new SimpleMode.RuleFilter() {
public boolean testRule(Rule r) {
int comp = r.compareRank(currentRule);
return comp < 0 || (comp == 0 && r.getSequence() < currentRule.getSequence());
}
};
return getRule(item, context, filter);
}
/**
* Export all template rules in this mode in a form that can be re-imported.
* Note that template rules with union patterns may have been split into multiple
* rules. We need to avoid outputting them more than once.
*
* @param out used to display the expression tree
*/
public abstract void exportTemplateRules(ExpressionPresenter out) throws XPathException;
/**
* Explain all template rules in this mode in a form that can be re-imported.
* Note that template rules with union patterns may have been split into multiple
* rules. We need to avoid outputting them more than once.
*
* @param out used to display the expression tree
*/
public abstract void explainTemplateRules(ExpressionPresenter out) throws XPathException;
/**
* Process selected nodes using the template rules registered for this mode.
*
* @param parameters A ParameterSet containing the parameters to
* the handler/template being invoked. Specify null if there are no
* parameters.
* @param tunnelParameters A ParameterSet containing the parameters to
* the handler/template being invoked. Specify null if there are no
* parameters.
* @param context A newly-created context object (this must be freshly created by the caller,
* as it will be modified by this method). The nodes to be processed are those
* selected by the currentIterator in this context object. There is also a precondition
* that this mode must be the current mode in this context object.
* @param locationId location of this apply-templates instruction in the stylesheet
* @return a TailCall returned by the last template to be invoked, or null,
* indicating that there are no outstanding tail calls.
* @throws XPathException if any dynamic error occurs
*/
/*@Nullable*/
public TailCall applyTemplates(
ParameterSet parameters,
ParameterSet tunnelParameters,
XPathContextMajor context,
Location locationId)
throws XPathException {
Controller controller = context.getController();
boolean tracing = controller.isTracing();
PipelineConfiguration pipe = context.getReceiver().getPipelineConfiguration();
SequenceIterator iterator = context.getCurrentIterator();
TailCall tc = null;
TraceListener traceListener = tracing ? controller.getTraceListener() : null;
// Iterate over this sequence
boolean lookahead = (iterator.getProperties() & SequenceIterator.LOOKAHEAD) != 0;
TemplateRule previousTemplate = null;
while (true) {
// process any tail calls returned from previous nodes. We need to do this before changing
// the context. If we have a LookaheadIterator, we can tell whether we're positioned at the
// end without changing the current position, and we can then return the last tail call to
// the caller and execute it further down the stack, reducing the risk of running out of stack
// space. In other cases, we need to execute the outstanding tail calls before moving the iterator
if (tc != null) {
if (lookahead && !((LookaheadIterator) iterator).hasNext()) {
break;
}
do {
tc = tc.processLeavingTail();
} while (tc != null);
}
Item item = iterator.next();
if (item == null) {
break;
}
if (mustBeTyped) {
if (item instanceof NodeInfo) {
int kind = ((NodeInfo) item).getNodeKind();
if (kind == Type.ELEMENT || kind == Type.ATTRIBUTE) {
SchemaType annotation = ((NodeInfo) item).getSchemaType();
if (annotation == Untyped.getInstance() || annotation == BuiltInAtomicType.UNTYPED_ATOMIC) {
throw new XPathException(getModeTitle() + " requires typed nodes, but the input is untyped", "XTTE3100");
}
}
}
} else if (mustBeUntyped) {
if (item instanceof NodeInfo) {
int kind = ((NodeInfo) item).getNodeKind();
if (kind == Type.ELEMENT || kind == Type.ATTRIBUTE) {
SchemaType annotation = ((NodeInfo) item).getSchemaType();
if (!(annotation == Untyped.getInstance() || annotation == BuiltInAtomicType.UNTYPED_ATOMIC)) {
throw new XPathException(getModeTitle() + " requires untyped nodes, but the input is typed", "XTTE3110");
}
}
}
}
pipe.pushCurrentAppliedItem(item);
// find the template rule for this node
if (tracing && traceListener instanceof TraceListener2) {
((TraceListener2)traceListener).startRuleSearch();
}
Rule rule = getRule(item, context);
if (tracing && traceListener instanceof TraceListener2) {
((TraceListener2) traceListener).endRuleSearch((rule != null) ? rule : getBuiltInRuleSet(), this, item);
}
if (rule == null) { // Use the default action for the node
// No need to open a new stack frame!
getBuiltInRuleSet().process(item, parameters, tunnelParameters, context, locationId);
} else {
TemplateRule template = (TemplateRule) rule.getAction();
if (template != previousTemplate) {
// Reuse the previous stackframe unless it's a different template rule
previousTemplate = template;
context.openStackFrame(template.getStackFrameMap());
context.setLocalParameters(parameters);
context.setTunnelParameters(tunnelParameters);
}
context.setCurrentTemplateRule(rule);
if (tracing) {
traceListener.startCurrentItem(item);
tc = template.applyLeavingTail(context);
if (tc != null) {
// disable tail call optimization while tracing
do {
tc = tc.processLeavingTail();
} while (tc != null);
}
traceListener.endCurrentItem(item);
} else {
tc = template.applyLeavingTail(context);
}
}
pipe.popCurrentAppliedItem();
}
// return the TailCall returned from the last node processed
return tc;
}
public abstract int getStackFrameSlotsNeeded();
/**
* Return a code string for a built-in rule set. This can be specialised in subclasses for PE/EE
*
* @param builtInRuleSet the rule set to get a code
* @return a simple string code or "???" if the ruleset is unknown
*/
public String getCodeForBuiltInRuleSet(BuiltInRuleSet builtInRuleSet) {
if (builtInRuleSet instanceof TextOnlyCopyRuleSet) {
return "TC";
} else {
return "???";
}
}
/**
* Return a built-in rule set for a code string. This can be specialised in subclasses for PE/EE
*
* @param code the code used in export
* @return a suitable ruleset
*/
public BuiltInRuleSet getBuiltInRuleSetForCode(String code) throws XPathException {
if (code.startsWith("TC")) {
return TextOnlyCopyRuleSet.getInstance();
} else {
throw new AssertionError();
}
}
public final void export(ExpressionPresenter presenter) throws XPathException {
int s = presenter.startElement("mode");
if (!isUnnamedMode()) {
presenter.emitAttribute("name", getModeName().getEQName());
}
presenter.emitAttribute("onNo", getCodeForBuiltInRuleSet(getBuiltInRuleSet()));
String flags = "";
if (isDeclaredStreamable()) {
flags += "s";
}
if (isUnnamedMode()) {
flags += "d";
}
if (mustBeTyped) {
flags += "t";
}
if (mustBeUntyped) {
flags += "u";
}
if (recoveryPolicy == Configuration.DO_NOT_RECOVER) {
flags += "F";
} else if (recoveryPolicy == Configuration.RECOVER_WITH_WARNINGS) {
flags += "W";
}
if (!flags.isEmpty()) {
presenter.emitAttribute("flags", flags);
}
presenter.emitAttribute("patternSlots", getStackFrameSlotsNeeded() + "");
exportTemplateRules(presenter);
int e = presenter.endElement();
if (s != e) {
throw new IllegalStateException("Export tree unbalanced for mode " + getModeName());
}
}
public void explain(ExpressionPresenter presenter) throws XPathException {
int s = presenter.startElement("mode");
if (!isUnnamedMode()) {
presenter.emitAttribute("name", getModeName());
}
presenter.emitAttribute("onNo", getCodeForBuiltInRuleSet(getBuiltInRuleSet()));
String flags = "";
if (isDeclaredStreamable()) {
flags += "s";
}
if (isUnnamedMode()) {
flags += "d";
}
if (mustBeTyped) {
flags += "t";
}
if (mustBeUntyped) {
flags += "u";
}
if (recoveryPolicy == Configuration.DO_NOT_RECOVER) {
flags += "F";
} else if (recoveryPolicy == Configuration.RECOVER_WITH_WARNINGS) {
flags += "W";
}
if (!flags.isEmpty()) {
presenter.emitAttribute("flags", flags);
}
presenter.emitAttribute("patternSlots", getStackFrameSlotsNeeded() + "");
explainTemplateRules(presenter);
int e = presenter.endElement();
if (s != e) {
throw new IllegalStateException("tree unbalanced");
}
}
/**
* Interface for helper classes used to filter a chain of rules
*/
protected interface RuleFilter {
/**
* Test a rule to see whether it should be included
*
* @param r the rule to be tested
* @return true if the rule qualifies
*/
boolean testRule(Rule r);
}
/**
* Interface for helper classes used to process all the rules in the Mode
*/
public interface RuleAction {
/**
* Process a given rule
*
* @param r the rule to be processed
* @throws XPathException if an error occurs, for example a dynamic error in evaluating a pattern
*/
void processRule(Rule r) throws XPathException;
}
}
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