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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018-2023 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.om;
import net.sf.saxon.event.ProxyReceiver;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.event.Stripper;
import net.sf.saxon.pattern.*;
import net.sf.saxon.style.StylesheetModule;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.trans.rules.Rule;
import net.sf.saxon.type.AlphaCode;
import net.sf.saxon.type.SchemaType;
import net.sf.saxon.type.Type;
import java.util.HashMap;
import java.util.Iterator;
import java.util.TreeMap;
/**
* A whitespace stripping rule that strips elected elements unless xml:space indicates that whitespace
* should be preserved.
*/
public class SelectedElementsSpaceStrippingRule implements SpaceStrippingRule {
// This is a cut-down version of the Mode class, which until 9.3 was used for the job, even though
// it is over-engineered for the task.
private Rule anyElementRule = null;
private Rule unnamedElementRuleChain = null;
private final HashMap namedElementRules = new HashMap(32);
private int sequence = 0;
private final boolean rejectDuplicates; // in XSLT 3.0, duplicate conflicting rules are a static error
/**
* Create the ruleset
*
* @param rejectDuplicates indicates whether duplicate conflicting rules are a static error
*/
public SelectedElementsSpaceStrippingRule(boolean rejectDuplicates) {
this.rejectDuplicates = rejectDuplicates;
}
/**
* Decide whether an element is in the set of white-space preserving element names
*
* @param fingerprint identifies the name of the element whose whitespace is to
* be preserved
* @param schemaType the type annotation of the element
* @return ALWAYS_PRESERVE if the element is in the set of white-space preserving
* element types, ALWAYS_STRIP if the element is to be stripped regardless of the
* xml:space setting, and STRIP_DEFAULT otherwise
*/
@Override
public int isSpacePreserving(NodeName fingerprint, SchemaType schemaType) throws XPathException {
Rule rule = getRule(fingerprint);
if (rule == null) {
return Stripper.ALWAYS_PRESERVE;
}
return rule.getAction() == Stripper.PRESERVE ? Stripper.ALWAYS_PRESERVE : Stripper.STRIP_DEFAULT;
}
/**
* Add a rule
*
* @param test a NodeTest (*, *:local, prefix:*, or QName)
* @param action StripRuleTarget.STRIP or StripRuleTarget.PRESERVE
* @param module the stylesheet module containing the rule
* @param lineNumber the line where the strip-space or preserve-space instruction appears
* @throws XPathException if this rule is a conflicting duplicate
*/
public void addRule(NodeTest test, Stripper.StripRuleTarget action,
StylesheetModule module, int lineNumber) throws XPathException {
// 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 precedence = module.getPrecedence();
int minImportPrecedence = module.getMinImportPrecedence();
NodeTestPattern pattern = new NodeTestPattern(test);
//pattern.setSystemId(module.getRootElement().getSystemId());
//pattern.setLineNumber(lineNumber);
addRule(pattern, action, precedence, minImportPrecedence);
}
public void addRule(NodeTestPattern pattern, Stripper.StripRuleTarget action, int precedence, int minImportPrecedence)
throws XPathException {
NodeTest test = pattern.getNodeTest();
double priority = test.getDefaultPriority();
Rule newRule = new Rule(pattern, action, precedence, minImportPrecedence, priority, sequence++, 0);
int prio = priority == 0 ? 2 : priority == -0.25 ? 1 : 0;
newRule.setRank((precedence << 18) + (prio << 16) + sequence);
if (test instanceof NodeKindTest) {
newRule.setAlwaysMatches(true);
anyElementRule = addRuleToList(newRule, anyElementRule, true);
} else if (test instanceof NameTest) {
newRule.setAlwaysMatches(true);
int fp = test.getFingerprint();
NamePool pool = ((NameTest) test).getNamePool();
FingerprintedQName key = new FingerprintedQName(pool.getUnprefixedQName(fp), pool);
Rule chain = namedElementRules.get(key);
namedElementRules.put(key, addRuleToList(newRule, chain, true));
} else {
unnamedElementRuleChain = addRuleToList(newRule, unnamedElementRuleChain, false);
}
}
/**
* Insert a new rule into this list before others of the same precedence
* (we rely on the fact that all rules in a list have the same priority)
*
* @param newRule the new rule to be added into the list
* @param list the Rule at the head of the list, or null if the list is empty
* @param dropRemainder if only one rule needs to be retained
* @return the new head of the list (which might be the old head, or the new rule if it
* was inserted at the start)
*/
private Rule addRuleToList(Rule newRule, Rule list, boolean dropRemainder) throws XPathException {
if (list == null) {
return newRule;
}
int precedence = newRule.getPrecedence();
Rule rule = list;
Rule prev = null;
while (rule != null) {
if (rule.getPrecedence() <= precedence) {
if (rejectDuplicates && rule.getPrecedence() == precedence && !rule.getAction().equals(newRule.getAction())) {
throw new XPathException(
"There are conflicting xsl:strip-space and xsl:preserve-space declarations for " +
rule.getPattern() + " at the same import precedence", "XTSE0270");
}
newRule.setNext(dropRemainder ? null : rule);
if (prev == null) {
return newRule;
} else {
prev.setNext(newRule);
}
break;
} else {
prev = rule;
rule = rule.getNext();
}
}
if (rule == null) {
prev.setNext(newRule);
newRule.setNext(null);
}
return list;
}
/**
* Get the rule corresponding to a given element node, by finding the best pattern match.
*
* @param nodeName the name of the element node to be matched
* @return the best matching rule, if any (otherwise null).
*/
/*@Nullable*/
public Rule getRule(NodeName nodeName) {
// search the specific list for this node type / node name
Rule bestRule = namedElementRules.get(nodeName);
// search the list for *:local and prefix:* node tests
if (unnamedElementRuleChain != null) {
bestRule = searchRuleChain(nodeName, bestRule, unnamedElementRuleChain);
}
// See if there is a "*" rule matching all elements
if (anyElementRule != null) {
bestRule = searchRuleChain(nodeName, bestRule, anyElementRule);
}
return bestRule;
}
/**
* Search a chain of rules
*
* @param nodeName the name of the element node being matched
* @param bestRule the best rule so far in terms of precedence and priority (may be null)
* @param head the rule at the head of the chain to be searched
* @return the best match rule found in the chain, or the previous best rule, or null
*/
private Rule searchRuleChain(NodeName nodeName, Rule bestRule, Rule head) {
while (head != null) {
if (bestRule != null) {
int rank = head.compareRank(bestRule);
if (rank < 0) {
// if we already have a match, and the precedence or priority of this
// rule is lower, quit the search
break;
} else if (rank == 0) {
// this rule has the same precedence and priority as the matching rule already found
if (head.isAlwaysMatches() ||
((NodeTest) head.getPattern().getItemType()).matches(Type.ELEMENT, nodeName, null)) {
// reportAmbiguity(bestRule, head);
// We no longer report the recoverable error XTRE0270, we always
// take the recovery action.
// choose whichever one comes last (assuming the error wasn't fatal)
bestRule = head;
break;
} else {
// keep searching other rules of the same precedence and priority
}
} else {
// this rule has higher rank than the matching rule already found
if (head.isAlwaysMatches() ||
((NodeTest) head.getPattern().getItemType()).matches(Type.ELEMENT, nodeName, null)) {
bestRule = head;
}
}
} else if (head.isAlwaysMatches() ||
((NodeTest) head.getPattern().getItemType()).matches(Type.ELEMENT, nodeName, null)) {
bestRule = head;
break;
}
head = head.getNext();
}
return bestRule;
}
/**
* Get all the rules in rank order, highest-ranking rules first
* @return the rules in rank order
*/
public Iterator getRankedRules() {
TreeMap treeMap = new TreeMap();
Rule rule = anyElementRule;
while (rule != null) {
treeMap.put(-rule.getRank(), rule);
rule = rule.getNext();
}
rule = unnamedElementRuleChain;
while (rule != null) {
treeMap.put(-rule.getRank(), rule);
rule = rule.getNext();
}
for (Rule r : namedElementRules.values()) {
treeMap.put(-r.getRank(), r);
}
return treeMap.values().iterator();
}
/**
* Make a filter to implement these space-stripping rules, or null if no filtering
* is necessary
*
* @return a filter in the form of a ProxyReceiver, or null
* @param next the Receiver that is to receive the filtered event stream
*/
@Override
public ProxyReceiver makeStripper(Receiver next) {
return new Stripper(this, next);
}
/**
* Export this rule as part of an exported stylesheet
*
* @param presenter the output handler
*/
@Override
public void export(ExpressionPresenter presenter) throws XPathException {
presenter.startElement("strip");
Rule rule = anyElementRule;
while (rule != null) {
exportRule(rule, presenter);
rule = rule.getNext();
}
rule = unnamedElementRuleChain;
while (rule != null) {
exportRule(rule, presenter);
rule = rule.getNext();
}
for (Rule r : namedElementRules.values()) {
exportRule(r, presenter);
}
presenter.endElement();
}
private static void exportRule(Rule rule, ExpressionPresenter presenter) {
String which = rule.getAction() == Stripper.STRIP ? "s" : "p";
presenter.startElement(which);
presenter.emitAttribute("test", AlphaCode.fromItemType(rule.getPattern().getItemType()));
presenter.emitAttribute("prec", rule.getPrecedence()+"");
presenter.endElement();
}
// private static void exportRuleJS(Rule rule, StringBuilder fsb) {
// String which = rule.getAction() == Stripper.STRIP ? "true" : "false";
// NodeTest test = (NodeTest)rule.getPattern().getItemType();
// if (test instanceof NodeKindTest) {
// // elements="*"
// fsb.append("return " + which + ";");
// } else if (test instanceof NameTest) {
// fsb.append("if (uri=='" + test.getMatchingNodeName().getURI() +
// "' && local=='" + test.getMatchingNodeName().getLocalPart() +
// "') return " + which + ";" );
// } else if (test instanceof NamespaceTest) {
// fsb.append("if (uri=='" + ((NamespaceTest)test).getNamespaceURI() + "') return " + which + ";");
// } else if (test instanceof LocalNameTest) {
// fsb.append("if (local=='" + ((LocalNameTest) test).getLocalName() + "') return " + which + ";");
// } else {
// throw new IllegalStateException("Cannot export " + test.getClass());
// }
// }
}