package net.sf.saxon.trans;
import net.sf.saxon.Configuration;
import net.sf.saxon.functions.NormalizeSpace;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.XPathContextMajor;
import net.sf.saxon.om.Navigator;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.pattern.NoNodeTest;
import net.sf.saxon.pattern.Pattern;
import net.sf.saxon.type.Type;
import java.io.Serializable;
/**
* A Mode is a collection of rules; the selection of a rule to apply to a given element
* is determined by a Pattern.
*
* @author Michael H. Kay
*/
public class Mode implements Serializable {
public static final int DEFAULT_MODE = -1;
public static final int ALL_MODES = -2;
public static final int NAMED_MODE = -3;
public static final int STRIPPER_MODE = -4;
private Rule[] ruleDict = new Rule[101 + Type.MAX_NODE_TYPE];
private int sequence = 0; // sequence number for the rules in this Mode
private boolean isDefault;
private boolean isStripper;
/**
* Default constructor - creates a Mode containing no rules
* @param usage one of {@link #DEFAULT_MODE}, {@link #NAMED_MODE}, {@link #STRIPPER_MODE}
*/
public Mode(int usage) {
this.isDefault = (usage == DEFAULT_MODE);
this.isStripper = (usage == STRIPPER_MODE);
}
/**
* Construct a new Mode, copying the contents of an existing Mode
*
* @param omniMode the existing mode. May be null, in which case it is not copied
*/
public Mode(Mode omniMode) {
isDefault = false;
isStripper = false;
if (omniMode != null) {
for (int i = 0; i < this.ruleDict.length; i++) {
if (omniMode.ruleDict[i] != null) {
this.ruleDict[i] = new Rule(omniMode.ruleDict[i]);
}
}
this.sequence = omniMode.sequence;
}
}
/**
* Determine if this is the default mode
*/
public boolean isDefaultMode() {
return isDefault;
}
/**
* Add a rule to the Mode. <br>
* The rule effectively replaces any other rule for the same pattern/mode at the same or a lower
* priority.
*
* @param p a Pattern
* @param obj the Object to return from getRule() when the supplied node matches this Pattern
* @param precedence the import precedence of the rule
* @param priority the explicit or implicit priority of the rule
*/
public void addRule(Pattern p, Object obj, int precedence, double priority) {
// System.err.println("Add rule, pattern = " + p.toString() + " class " + p.getClass() + ", priority=" + priority);
// Ignore a pattern that will never match, e.g. "@comment"
if (p.getNodeTest() instanceof NoNodeTest) {
return;
}
// for fast lookup, we maintain one list for each element name for patterns that can only
// match elements of a given name, one list for each node type for patterns that can only
// match one kind of non-element node, and one generic list.
// Each list is sorted in precedence/priority order so we find the highest-priority rule first
int fingerprint = p.getFingerprint();
int type = p.getNodeKind();
int key = getList(fingerprint, type);
// System.err.println("Fingerprint " + fingerprint + " key " + key + " type " + type);
Rule newRule = new Rule(p, obj, precedence, priority, sequence++);
Rule rule = ruleDict[key];
if (rule == null) {
ruleDict[key] = newRule;
return;
}
// insert the new rule into this list before others of the same precedence/priority
Rule prev = null;
while (rule != null) {
if ((rule.precedence < precedence) ||
(rule.precedence == precedence && rule.priority <= priority)) {
newRule.next = rule;
if (prev == null) {
ruleDict[key] = newRule;
} else {
prev.next = newRule;
}
break;
} else {
prev = rule;
rule = rule.next;
}
}
if (rule == null) {
prev.next = newRule;
newRule.next = null;
}
}
/**
* Determine which list to use for a given pattern (we must also search the generic list)
*/
public int getList(int fingerprint, int type) {
if (type == Type.ELEMENT) {
if (fingerprint == -1) {
return Type.NODE; // the generic list
} else {
return Type.MAX_NODE_TYPE +
(fingerprint % 101);
}
} else {
return type;
}
}
/**
* Get the rule corresponding to a given Node, by finding the best Pattern match.
*
* @param node the NodeInfo referring to the node to be matched
* @return the object (e.g. a NodeHandler) registered for that element, if any (otherwise null).
*/
public Object getRule(NodeInfo node, XPathContext context) throws XPathException {
int fingerprint = node.getFingerprint();
// This is inefficient with wrapped object models (DOM, XOM, JDOM),
// but there's not much we can do about it
int type = node.getNodeKind();
int key = getList(fingerprint, type);
int policy = context.getController().getRecoveryPolicy();
// If there are match patterns in the stylesheet that use local variables, we need to allocate
// a new stack frame for evaluating the match patterns. We base this on the match pattern with
// the highest number of range variables, so we can reuse the same stack frame for all rules
// that we test against. If no patterns use range variables, we don't bother allocating a new
// stack frame.
context = perhapsMakeNewContext(context);
Rule specificRule = null;
Rule generalRule = null;
int specificPrecedence = -1;
double specificPriority = Double.NEGATIVE_INFINITY;
// search the specific list for this node type / node name
if (key != Type.NODE) {
Rule r = ruleDict[key];
while (r != null) {
// if we already have a match, and the precedence or priority of this
// rule is lower, quit the search for a second match
if (specificRule != null) {
if (r.precedence < specificPrecedence ||
(r.precedence == specificPrecedence && r.priority < specificPriority)) {
break;
}
}
if (r.pattern.matches(node, context)) {
// is this a second match?
if (specificRule != null) {
if (r.precedence == specificPrecedence && r.priority == specificPriority) {
reportAmbiguity(node, specificRule, r, context);
}
break;
}
specificRule = r;
specificPrecedence = r.precedence;
specificPriority = r.priority;
if (policy == Configuration.RECOVER_SILENTLY) {
break; // find the first; they are in priority order
}
}
r = r.next;
}
}
// search the general list
Rule r2 = ruleDict[Type.NODE];
while (r2 != null) {
if (r2.precedence < specificPrecedence ||
(r2.precedence == specificPrecedence && r2.priority < specificPriority)) {
break; // no point in looking at a lower priority rule than the one we've got
}
if (r2.pattern.matches(node, context)) {
// is it a second match?
if (generalRule != null) {
if (r2.precedence == generalRule.precedence && r2.priority == generalRule.priority) {
reportAmbiguity(node, r2, generalRule, context);
}
break;
} else {
generalRule = r2;
if (policy == Configuration.RECOVER_SILENTLY) {
break; // find only the first; they are in priority order
}
}
}
r2 = r2.next;
}
if (specificRule != null && generalRule == null) {
return specificRule.object;
}
if (specificRule == null && generalRule != null) {
return generalRule.object;
}
if (specificRule != null && generalRule != null) {
if (specificRule.precedence == generalRule.precedence &&
specificRule.priority == generalRule.priority) {
// This situation is exceptional: we have a "specific" pattern and
// a "general" pattern with the same priority. We have to select
// the one that was added last
// (Bug reported by Norman Walsh Jan 2002)
Object result = (specificRule.sequence > generalRule.sequence ?
specificRule.object :
generalRule.object);
if (policy != Configuration.RECOVER_SILENTLY) {
reportAmbiguity(node, specificRule, generalRule, context);
}
return result;
}
if (specificRule.precedence > generalRule.precedence ||
(specificRule.precedence == generalRule.precedence &&
specificRule.priority >= generalRule.priority)) {
return specificRule.object;
} else {
return generalRule.object;
}
}
return null;
}
/**
* 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 (or the existing context if no new context was created)
*/
private XPathContext perhapsMakeNewContext(XPathContext context) {
int patternLocals = context.getController().getExecutable().getLargestPatternStackFrame();
if (patternLocals > 0) {
context = context.newContext();
context.setOrigin(context.getController());
((XPathContextMajor)context).openStackFrame(patternLocals);
}
return context;
}
/**
* 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 node the NodeInfo referring to the node to be matched
* @return the object (e.g. a NodeHandler) registered for that element, if any (otherwise null).
*/
public Object getRule(NodeInfo node, int min, int max, XPathContext context) throws XPathException {
int fing = node.getFingerprint();
int type = node.getNodeKind();
int key = getList(fing, type);
Rule specificRule = null;
Rule generalRule = null;
context = perhapsMakeNewContext(context);
// search the the specific list for this node type / name
if (key != Type.NODE) {
Rule r = ruleDict[key];
while (r != null) {
if (r.precedence >= min && r.precedence <= max &&
r.pattern.matches(node, context)) {
specificRule = r;
break; // find the first; they are in priority order
}
r = r.next;
}
}
// search the generic list
Rule r2 = ruleDict[Type.NODE];
while (r2 != null) {
if (r2.precedence >= min && r2.precedence <= max && r2.pattern.matches(node, context)) {
generalRule = r2;
break; // find only the first; they are in priority order
}
r2 = r2.next;
}
if (specificRule != null && generalRule == null) {
return specificRule.object;
}
if (specificRule == null && generalRule != null) {
return generalRule.object;
}
if (specificRule != null && generalRule != null) {
if (specificRule.precedence > generalRule.precedence ||
(specificRule.precedence == generalRule.precedence &&
specificRule.priority >= generalRule.priority)) {
return specificRule.object;
} else {
return generalRule.object;
}
}
return null;
}
/**
* Get the rule corresponding to a given Node, by finding the next-best Pattern match
* after the specified object.
*
* @param node the NodeInfo referring to the node to be matched
* @return the object (e.g. a NodeHandler) registered for that element, if any (otherwise null).
*/
public Object getNextMatchRule(NodeInfo node, Object currentHandler, XPathContext context) throws XPathException {
int fingerprint = node.getFingerprint();
int type = node.getNodeKind();
int key = getList(fingerprint, type);
int policy = context.getController().getRecoveryPolicy();
int currentPrecedence = -1;
double currentPriority = -1.0;
int currentSequence = -1;
context = perhapsMakeNewContext(context);
// First find the Rule object corresponding to the current handler
Rule r = ruleDict[key];
while (r != null) {
if (r.object == currentHandler) {
currentPrecedence = r.precedence;
currentPriority = r.priority;
currentSequence = r.sequence;
break;
} else {
r = r.next;
}
}
if (r == null) {
r = ruleDict[Type.NODE];
while (r != null) {
if (r.object == currentHandler) {
currentPrecedence = r.precedence;
currentPriority = r.priority;
currentSequence = r.sequence;
break;
} else {
r = r.next;
}
}
if (r == null) {
DynamicError de = new DynamicError("Internal error: current template doesn't match current node");
de.setXPathContext(context);
de.setErrorCode("SAXON:0000");
throw de;
}
}
Rule specificRule = null;
Rule generalRule = null;
int specificPrecedence = -1;
double specificPriority = Double.NEGATIVE_INFINITY;
// search the specific list for this node type / node name
// System.err.println("Hash key = " + key);
if (key != Type.NODE) {
r = ruleDict[key];
while (r != null) {
// skip this rule if its template is the current template. (There can be more than
// one rule for the same template in the case of a union pattern.)
if (r.object == currentHandler) {
// skip this rule
} else
// skip this rule unless it's "below" the current rule in search order
if ((r.precedence > currentPrecedence) ||
(r.precedence == currentPrecedence &&
(r.priority > currentPriority ||
(r.priority == currentPriority && r.sequence >= currentSequence)))) {
// skip this rule
} else {
// quit the search on finding the second (recoverable error) match
if (specificRule != null) {
if (r.precedence < specificPrecedence ||
(r.precedence == specificPrecedence && r.priority < specificPriority)) {
break;
}
}
//System.err.println("Testing " + Navigator.getPath(node) + " against " + r.pattern);
if (r.pattern.matches(node, context)) {
//System.err.println("Matches");
// is this a second match?
if (specificRule != null) {
if (r.precedence == specificPrecedence && r.priority == specificPriority) {
reportAmbiguity(node, specificRule, r, context);
}
break;
}
specificRule = r;
specificPrecedence = r.precedence;
specificPriority = r.priority;
if (policy == Configuration.RECOVER_SILENTLY) {
break; // find the first; they are in priority order
}
}
}
r = r.next;
}
}
// search the general list
Rule r2 = ruleDict[Type.NODE];
while (r2 != null) {
// skip this rule if the template is the current template
if (r2.object == currentHandler) {
// skip this rule
} else
// skip this rule unless it's "after" the current rule in search order
if ((r2.precedence > currentPrecedence) ||
(r2.precedence == currentPrecedence &&
(r2.priority > currentPriority ||
(r2.priority == currentPriority && r2.sequence >= currentSequence)))) {
// skip this rule
} else {
if (r2.precedence < specificPrecedence ||
(r2.precedence == specificPrecedence && r2.priority < specificPriority)) {
break; // no point in looking at a lower priority rule than the one we've got
}
if (r2.pattern.matches(node, context)) {
// is it a second match?
if (generalRule != null) {
if (r2.precedence == generalRule.precedence && r2.priority == generalRule.priority) {
reportAmbiguity(node, r2, generalRule, context);
}
break;
} else {
generalRule = r2;
if (policy == Configuration.RECOVER_SILENTLY) {
break; // find only the first; they are in priority order
}
}
}
}
r2 = r2.next;
}
if (specificRule != null && generalRule == null) {
return specificRule.object;
}
if (specificRule == null && generalRule != null) {
return generalRule.object;
}
if (specificRule != null && generalRule != null) {
if (specificRule.precedence == generalRule.precedence &&
specificRule.priority == generalRule.priority) {
// This situation is exceptional: we have a "specific" pattern and
// a "general" pattern with the same priority. We have to select
// the one that was added last
// (Bug reported by Norman Walsh Jan 2002)
Object result = (specificRule.sequence > generalRule.sequence ?
specificRule.object :
generalRule.object);
if (policy != Configuration.RECOVER_SILENTLY) {
reportAmbiguity(node, specificRule, generalRule, context);
}
return result;
}
if (specificRule.precedence > generalRule.precedence ||
(specificRule.precedence == generalRule.precedence &&
specificRule.priority >= generalRule.priority)) {
return specificRule.object;
} else {
return generalRule.object;
}
}
return null;
}
/**
* Report an ambiguity, that is, the situation where two rules of the same
* precedence and priority match the same node
*
* @param node The node that matches two or more rules
* @param r1 The first rule that the node matches
* @param r2 The second rule that the node matches
* @param c The controller for the transformation
*/
private void reportAmbiguity(NodeInfo node, Rule r1, Rule r2, XPathContext c)
throws XPathException {
// don't report an error if the conflict is between two branches of the same
// Union pattern
if (r1.object == r2.object) {
return;
}
String path;
String errorCode = "XTRE0540";
if (isStripper) {
// don't report an error if the conflict is between strip-space and strip-space, or
// preserve-space and preserve-space
if (r1.object.equals(r2.object)) {
return;
}
errorCode = "XTRE0270";
path = "xsl:strip-space";
} else {
path = Navigator.getPath(node);
}
Pattern pat1 = r1.pattern;
Pattern pat2 = r2.pattern;
DynamicError err = new DynamicError("Ambiguous rule match for " + path + '\n' +
"Matches both \"" + showPattern(pat1) + "\" on line " + pat1.getLineNumber() + " of " + pat1.getSystemId() +
"\nand \"" + showPattern(pat2) + "\" on line " + pat2.getLineNumber() + " of " + pat2.getSystemId());
err.setErrorCode(errorCode);
err.setLocator(c.getOrigin().getInstructionInfo());
c.getController().recoverableError(err);
}
private static String showPattern(Pattern p) {
// Complex patterns can be laid out with lots of whitespace, which looks messy in the error message
return NormalizeSpace.normalize(p.toString()).toString();
}
/**
* Inner class Rule used to support the implementation
*/
public static class Rule implements Serializable {
public Pattern pattern;
public Object object;
public int precedence;
public double priority;
public int sequence;
public Rule next;
/**
* Create a Rule
*
* @param p the pattern that this rule matches
* @param o the object invoked by this rule (usually a Template)
* @param prec the precedence of the rule
* @param prio the priority of the rule
* @param seq a sequence number for ordering of rules
*/
public Rule(Pattern p, Object o, int prec, double prio, int seq) {
pattern = p;
object = o;
precedence = prec;
priority = prio;
next = null;
sequence = seq;
}
/**
* Copy a rule, including the chain of rules linked to it
*
* @param r
*/
public Rule(Rule r) {
this.pattern = r.pattern;
this.object = r.object;
this.precedence = r.precedence;
this.priority = r.priority;
this.sequence = r.sequence;
if (r.next == null) {
this.next = null;
} else {
this.next = new Rule(r.next);
}
}
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//
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