/*
* eXist Open Source Native XML Database
* Copyright (C) 2008-2009 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xslt.pattern;
import java.io.IOException;
import java.io.Reader;
import java.text.NumberFormat;
import org.apache.log4j.Logger;
import org.exist.interpreter.ContextAtExist;
import org.exist.source.Source;
import org.exist.source.StringSource;
import org.exist.xquery.AnalyzeContextInfo;
import org.exist.xquery.AnyNodeTest;
import org.exist.xquery.Constants;
import org.exist.xquery.LocationStep;
import org.exist.xquery.PathExpr;
import org.exist.xquery.StaticXQueryException;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.parser.XQueryLexer;
import org.exist.xquery.parser.XQueryParser;
import org.exist.xquery.parser.XQueryTreeParser;
import org.exist.xquery.util.ExpressionDumper;
import antlr.RecognitionException;
import antlr.TokenStreamException;
import antlr.collections.AST;
/**
* [1] Pattern ::= PathPattern <br>
* | Pattern '|' PathPattern <br>
* [2] PathPattern ::= RelativePathPattern <br>
* | '/' RelativePathPattern? <br>
* | '//' RelativePathPattern <br>
* | IdKeyPattern (('/' | '//') RelativePathPattern)? <br>
* [3] RelativePathPattern ::= PatternStep (('/' | '//') RelativePathPattern)? <br>
* [4] PatternStep ::= PatternAxis? NodeTest XP PredicateListXP <br>
* [5] PatternAxis ::= ('child' '::' | 'attribute' '::' | '@') <br>
* [6] IdKeyPattern ::= 'id' '(' IdValue ')' <br>
* | 'key' '(' StringLiteralXP ',' KeyValue ')' <br>
* [7] IdValue ::= StringLiteralXP | VarRef XP <br>
* [8] KeyValue ::= Literal XP | VarRef XP <br>
* <br>
* The constructs NodeTest XP, PredicateList XP, VarRef XP, Literal XP, and StringLiteral XP are part of the XPath expression language, and are defined in [XPath 2.0].
*
* @author <a href="mailto:shabanovd@gmail.com">Dmitriy Shabanov</a>
*
*/
public class Pattern {
private final static Logger LOG = Logger.getLogger(Pattern.class);
static final String ELEMENT = "element()";
static final String ELEMENT_A = "element(*)";
static final String ATTRIBUTE = "attribute()";
static final String ATTRIBUTE_A = "attribute(*)";
public static void parse(ContextAtExist context, String pattern, PathExpr content) throws XPathException {
boolean xpointer = false;
//TODO: rewrite RootNode?
if (pattern.equals("//")) {
content.add(new LocationStep((XQueryContext) context, Constants.SELF_AXIS, new AnyNodeTest()));
return;
}
if (pattern.equals("/")) {
content.add(new LocationStep((XQueryContext) context, Constants.SELF_AXIS, new AnyNodeTest()));
return;
}
Source source = new StringSource(pattern);
Reader reader;
try {
reader = source.getReader();
} catch (IOException e1) {
return;//TODO: report error???
}
long start = System.currentTimeMillis();
XQueryLexer lexer = new XQueryLexer((XQueryContext) context, reader);
XQueryParser parser = new XQueryParser(lexer);
XQueryTreeParser treeParser = new XQueryTreeParser((XQueryContext) context);
try {
if (xpointer)
parser.xpointer();
else
parser.xpath();
if (parser.foundErrors()) {
LOG.debug(parser.getErrorMessage());
throw new StaticXQueryException(
parser.getErrorMessage());
}
AST ast = parser.getAST();
if (ast == null)
throw new XPathException("Unknown XQuery parser error: the parser returned an empty syntax tree.");
PathExpr expr = new PathExpr((XQueryContext) context);
if (xpointer)
treeParser.xpointer(ast, expr);
else
treeParser.xpath(ast, expr);
if (treeParser.foundErrors()) {
throw new StaticXQueryException(
treeParser.getErrorMessage(),
treeParser.getLastException());
}
expr.analyze(new AnalyzeContextInfo());
// if (context.optimizationsEnabled()) {
// Optimizer optimizer = new Optimizer(context);
// expr.accept(optimizer);
// if (optimizer.hasOptimized()) {
// context.reset(true);
// expr.resetState(true);
// expr.analyze(new AnalyzeContextInfo());
// }
// }
// Log the query if it is not too large, but avoid
// dumping huge queries to the log
if (context.getExpressionCount() < 150) {
LOG.debug("Query diagnostics:\n" + ExpressionDumper.dump(expr));
} else {
LOG.debug("Query diagnostics:\n" + "[skipped: more than 150 expressions]");
}
if (LOG.isDebugEnabled()) {
NumberFormat nf = NumberFormat.getNumberInstance();
LOG.debug("Compilation took " + nf.format(System.currentTimeMillis() - start) + " ms");
}
//return
content.add(expr);
} catch (RecognitionException e) {
LOG.debug("Error compiling query: " + e.getMessage(), e);
String msg = e.getMessage();
if (msg.endsWith(", found 'null'"))
msg = msg.substring(0, msg.length() - ", found 'null'".length());
throw new StaticXQueryException(e.getLine(), e.getColumn(), msg);
} catch (TokenStreamException e) {
LOG.debug("Error compiling query: " + e.getMessage(), e);
throw new StaticXQueryException(e.getMessage(), e);
}
}
}