/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2007 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
package org.exist.xquery;
import antlr.RecognitionException;
import antlr.TokenStreamException;
import antlr.collections.AST;
import com.sun.xacml.ctx.RequestCtx;
import java.io.File;
import java.io.IOException;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.text.NumberFormat;
import java.util.Properties;
import org.apache.log4j.Logger;
import org.exist.debuggee.Debuggee;
import org.exist.security.EffectiveSubject;
import org.exist.security.Permission;
import org.exist.security.PermissionDeniedException;
import org.exist.security.Subject;
import org.exist.security.xacml.AccessContext;
import org.exist.security.xacml.ExistPDP;
import org.exist.security.xacml.XACMLSource;
import org.exist.source.DBSource;
import org.exist.source.FileSource;
import org.exist.source.Source;
import org.exist.source.StringSource;
import org.exist.storage.DBBroker;
import org.exist.storage.XQueryPool;
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 org.exist.xquery.util.HTTPUtils;
import org.exist.xquery.value.Sequence;
/**
* @author wolf
*/
//TODO: it possible to have one per database
public class XQuery {
private final static Logger LOG = Logger.getLogger(XQuery.class);
private final DBBroker broker;
/**
* @param broker DBBroker to use for compilation and execution
*/
public XQuery(final DBBroker broker) {
this.broker = broker;
}
public XQueryContext newContext(final AccessContext accessCtx) {
return new XQueryContext(broker.getBrokerPool(), accessCtx);
}
public XQueryPool getXQueryPool() {
return broker.getBrokerPool().getXQueryPool();
}
public CompiledXQuery compile(final XQueryContext context, final String expression) throws XPathException, PermissionDeniedException {
final Source source = new StringSource(expression);
try {
return compile(context, source);
} catch(final IOException ioe) {
//should not happen because expression is a String
throw new XPathException(ioe.getMessage());
}
}
public CompiledXQuery compile(final XQueryContext context, final Source source) throws XPathException, IOException, PermissionDeniedException {
return compile(context, source, false);
}
public CompiledXQuery compile(final XQueryContext context, final Source source, final boolean xpointer) throws XPathException, IOException, PermissionDeniedException {
context.setSource(source);
context.setXacmlSource(XACMLSource.getInstance(source));
Reader reader;
try {
reader = source.getReader();
} catch(final UnsupportedEncodingException e) {
throw new XPathException(ErrorCodes.XQST0087, "unsupported encoding " + e.getMessage());
}
try {
return compile(context, reader, xpointer);
} finally {
if(reader != null) {
reader.close();
}
}
}
private CompiledXQuery compile(final XQueryContext context, final Reader reader, final boolean xpointer) throws XPathException, PermissionDeniedException {
//check read permission
context.getSource().validate(broker.getSubject(), Permission.READ);
//TODO: move XQueryContext.getUserFromHttpSession() here, have to check if servlet.jar is in the classpath
//before compiling/executing that code though to avoid a dependency on servlet.jar - reflection? - deliriumsky
// how about - if(XQuery.class.getResource("servlet.jar") != null) do load my class with dependency and call method?
/*
<|wolf77|> I think last time I checked, I already had problems with the call to
<|wolf77|> HTTPUtils.addLastModifiedHeader( result, context );
<|wolf77|> in line 184 of XQuery.java, because it introduces another dependency on HTTP.
*/
final long start = System.currentTimeMillis();
final XQueryLexer lexer = new XQueryLexer(context, reader);
final XQueryParser parser = new XQueryParser(lexer);
final XQueryTreeParser treeParser = new XQueryTreeParser(context);
try {
if(xpointer) {
parser.xpointer();
} else {
parser.xpath();
}
if(parser.foundErrors()) {
LOG.debug(parser.getErrorMessage());
throw new StaticXQueryException(parser.getErrorMessage());
}
final AST ast = parser.getAST();
if(ast == null) {
throw new XPathException("Unknown XQuery parser error: the parser returned an empty syntax tree.");
}
// LOG.debug("Generated AST: " + ast.toStringTree());
final PathExpr expr = new PathExpr(context);
if(xpointer) {
treeParser.xpointer(ast, expr);
} else {
treeParser.xpath(ast, expr);
}
if(treeParser.foundErrors()) {
//AST treeAst = treeParser.getAST();
throw new StaticXQueryException(ast.getLine(), ast.getColumn(), treeParser.getErrorMessage(), treeParser.getLastException());
}
context.getRootContext().resolveForwardReferences();
context.analyzeAndOptimizeIfModulesChanged(expr);
// Log the query if it is not too large, but avoid
// dumping huge queries to the log
if(LOG.isDebugEnabled()){
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()) {
final NumberFormat nf = NumberFormat.getNumberInstance();
LOG.debug("Compilation took " + nf.format(System.currentTimeMillis() - start) + " ms");
}
return expr;
} catch(final 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(final TokenStreamException e) {
final String es = e.toString();
if(es.matches("^line \\d+:\\d+:.+")) {
LOG.debug("Error compiling query: " + e.getMessage(), e);
final int line = Integer.parseInt(es.substring(5, es.indexOf(':')));
final String tmpColumn = es.substring(es.indexOf(':') + 1);
final int column = Integer.parseInt(tmpColumn.substring(0, tmpColumn.indexOf(':')));
throw new StaticXQueryException(line, column, e.getMessage(), e);
} else {
LOG.debug("Error compiling query: " + e.getMessage(), e);
throw new StaticXQueryException(e.getMessage(), e);
}
}
}
public Sequence execute(final CompiledXQuery expression, final Sequence contextSequence) throws XPathException, PermissionDeniedException {
return execute(expression, contextSequence, null);
}
public Sequence execute(final CompiledXQuery expression, final Sequence contextSequence, final Properties outputProperties) throws XPathException, PermissionDeniedException {
final XQueryContext context = expression.getContext();
final Sequence result = execute(expression, contextSequence, outputProperties, true);
//TODO : move this elsewhere !
HTTPUtils.addLastModifiedHeader(result, context);
return result;
}
public Sequence execute(final CompiledXQuery expression, final Sequence contextSequence, final boolean resetContext) throws XPathException, PermissionDeniedException {
return execute(expression, contextSequence, null, resetContext);
}
public Sequence execute(final CompiledXQuery expression, final Sequence contextSequence, final Properties outputProperties, final boolean resetContext) throws XPathException, PermissionDeniedException {
//check execute permissions
expression.getContext().getSource().validate(broker.getSubject(), Permission.EXECUTE);
final long start = System.currentTimeMillis();
final XQueryContext context = expression.getContext();
//check access to the query
final XACMLSource source = expression.getSource();
try {
final ExistPDP pdp = context.getPDP();
if(pdp != null) {
final RequestCtx request = pdp.getRequestHelper().createQueryRequest(context, source);
pdp.evaluate(request);
}
} catch(final PermissionDeniedException pde) {
throw new XPathException("Permission to execute query: " + source.createId() + " denied.", pde);
}
expression.reset();
if(resetContext) {
//context.setBroker(broker);
context.getWatchDog().reset();
}
if(context.requireDebugMode()) {
final Debuggee debuggee = broker.getBrokerPool().getDebuggee();
if (debuggee != null) {
debuggee.joint(expression);
}
}
//do any preparation before execution
context.prepareForExecution();
final Subject callingUser = broker.getSubject();
//if setUid or setGid, become Effective User
EffectiveSubject effectiveSubject = null;
final Source src = expression.getContext().getSource();
if(src instanceof DBSource) {
final DBSource dbSrc = (DBSource)src;
final Permission perm = dbSrc.getPermissions();
if(perm.isSetUid()) {
if(perm.isSetGid()) {
//setUid and SetGid
effectiveSubject = new EffectiveSubject(perm.getOwner(), perm.getGroup());
} else {
//just setUid
effectiveSubject = new EffectiveSubject(perm.getOwner());
}
} else if(perm.isSetGid()) {
//just setGid, so we use the current user as the effective user
effectiveSubject = new EffectiveSubject(callingUser, perm.getGroup());
}
}
try {
if(effectiveSubject != null) {
broker.setSubject(effectiveSubject); //switch to effective user (e.g. setuid/setgid)
}
context.getProfiler().traceQueryStart();
broker.getBrokerPool().getProcessMonitor().queryStarted(context.getWatchDog());
try {
final Sequence result = expression.eval(contextSequence);
if(LOG.isDebugEnabled()) {
final NumberFormat nf = NumberFormat.getNumberInstance();
LOG.debug("Execution took " + nf.format(System.currentTimeMillis() - start) + " ms");
}
if(outputProperties != null) {
context.checkOptions(outputProperties); //must be done before context.reset!
}
return result;
} finally {
context.getProfiler().traceQueryEnd(context);
expression.reset();
if(resetContext) {
context.reset();
}
broker.getBrokerPool().getProcessMonitor().queryCompleted(context.getWatchDog());
}
} finally {
if(effectiveSubject != null) {
broker.setSubject(callingUser);
}
}
}
public Sequence execute(final String expression, final Sequence contextSequence, final AccessContext accessCtx) throws XPathException, PermissionDeniedException {
final XQueryContext context = new XQueryContext(broker.getBrokerPool(), accessCtx);
final CompiledXQuery compiled = compile(context, expression);
return execute(compiled, contextSequence);
}
public Sequence execute(File file, Sequence contextSequence, AccessContext accessCtx) throws XPathException, IOException, PermissionDeniedException {
final XQueryContext context = new XQueryContext(broker.getBrokerPool(), accessCtx);
final CompiledXQuery compiled = compile(context, new FileSource(file, "UTF-8", true));
return execute(compiled, contextSequence);
}
}