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eXist-db NoSQL Database Core
/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2015 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.
*/
package org.exist.xmldb;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.exist.EXistException;
import org.exist.debuggee.Debuggee;
import org.exist.security.PermissionDeniedException;
import org.exist.security.Subject;
import org.exist.source.DBSource;
import org.exist.source.FileSource;
import org.exist.source.Source;
import org.exist.storage.BrokerPool;
import org.exist.storage.DBBroker;
import org.exist.storage.XQueryPool;
import org.exist.storage.lock.Lock.LockMode;
import org.exist.storage.lock.LockedDocumentMap;
import org.exist.storage.serializers.EXistOutputKeys;
import org.exist.storage.txn.Txn;
import org.exist.util.LockException;
import org.exist.xmldb.function.LocalXmldbFunction;
import org.exist.xquery.value.AnyURIValue;
import org.exist.xquery.value.BinaryValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.w3c.dom.Node;
import org.xmldb.api.base.*;
import org.xmldb.api.base.Collection;
import org.xmldb.api.modules.XMLResource;
import java.io.Writer;
import java.util.*;
import org.exist.dom.persistent.BinaryDocument;
import org.exist.dom.persistent.DefaultDocumentSet;
import org.exist.dom.persistent.DocumentImpl;
import org.exist.dom.persistent.ExtArrayNodeSet;
import org.exist.dom.persistent.MutableDocumentSet;
import org.exist.dom.persistent.NodeProxy;
import org.exist.dom.persistent.NodeSet;
import org.exist.security.Permission;
import com.evolvedbinary.j8fu.Either;
import org.exist.xquery.CompiledXQuery;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQuery;
import org.exist.xquery.XQueryContext;
public class LocalXPathQueryService extends AbstractLocalService implements EXistXPathQueryService, EXistXQueryService {
private final static Logger LOG = LogManager.getLogger(LocalXPathQueryService.class);
private final TreeMap namespaceDecls = new TreeMap<>();
private final TreeMap variableDecls = new TreeMap<>();
private boolean xpathCompatible = true;
private String moduleLoadPath = null;
private final Properties properties;
private boolean lockDocuments = false;
private LockedDocumentMap lockedDocuments = null;
private DBBroker reservedBroker = null;
public LocalXPathQueryService(final Subject user, final BrokerPool pool, final LocalCollection collection) {
super(user, pool, collection);
this.properties = new Properties(collection.getProperties());
}
@Override
public String getName() throws XMLDBException {
return "XPathQueryService";
}
@Override
public String getVersion() throws XMLDBException {
return "1.0";
}
@Override
public void clearNamespaces() throws XMLDBException {
namespaceDecls.clear();
}
@Override
public String getNamespace(final String prefix) throws XMLDBException {
return namespaceDecls.get(prefix);
}
@Override
public String getProperty(final String property) throws XMLDBException {
return properties.getProperty(property);
}
@Override
public ResourceSet query(final String query) throws XMLDBException {
return query(query, null);
}
@Override
public ResourceSet query(final XMLResource res, final String query) throws XMLDBException {
return query(res, query, null);
}
@Override
public ResourceSet query(final String query, final String sortBy) throws XMLDBException {
return withDb((broker, transaction) -> {
final XmldbURI[] docs = new XmldbURI[] { XmldbURI.create(collection.getName(broker, transaction)) };
return doQuery(broker, transaction, query, docs, null, sortBy);
});
}
@Override
public ResourceSet query(final XMLResource res, final String query, final String sortBy) throws XMLDBException {
final Node n = ((LocalXMLResource) res).root;
return withDb((broker, transaction) -> {
if (n != null && n instanceof org.exist.dom.memtree.NodeImpl) {
final XmldbURI[] docs = new XmldbURI[]{ getCollectionUri(broker, transaction, res.getParentCollection()) };
return doQuery(broker, transaction, query, docs, (org.exist.dom.memtree.NodeImpl) n, sortBy);
}
final NodeProxy node = ((LocalXMLResource) res).getNode(broker, transaction);
if (node == null) {
// resource is a document
//TODO : use dedicated function in XmldbURI
final XmldbURI[] docs = new XmldbURI[]{ getCollectionUri(broker, transaction, res.getParentCollection()).append(res.getDocumentId()) };
return doQuery(broker, transaction, query, docs, null, sortBy);
} else {
final NodeSet set = new ExtArrayNodeSet(1);
set.add(node);
final XmldbURI[] docs = new XmldbURI[]{node.getOwnerDocument().getURI()};
return doQuery(broker, transaction, query, docs, set, sortBy);
}
});
}
private ResourceSet doQuery(final DBBroker broker, final Txn transaction, final String query, final XmldbURI[] docs, final Sequence contextSet, final String sortExpr) throws XMLDBException {
final Either maybeExpr = compileAndCheck(broker, transaction, query);
if(maybeExpr.isLeft()) {
final XPathException e = maybeExpr.left().get();
throw new XMLDBException(ErrorCodes.VENDOR_ERROR, e.getMessage(), e);
} else {
return execute(broker, transaction, docs, contextSet, maybeExpr.right().get(), sortExpr);
}
}
@Override
public ResourceSet execute(final CompiledExpression expression) throws XMLDBException {
return withDb((broker, transaction) ->
execute(broker, transaction, null, null, expression, null));
}
@Override
public ResourceSet execute(final XMLResource res, final CompiledExpression expression) throws XMLDBException {
return withDb((broker, transaction) -> {
final NodeProxy node = ((LocalXMLResource) res).getNode(broker, transaction);
if (node == null) {
// resource is a document
final XmldbURI[] docs = new XmldbURI[]{ getCollectionUri(broker, transaction, res.getParentCollection()).append(res.getDocumentId()) };
return execute(broker, transaction, docs, null, expression, null);
} else {
final NodeSet set = new ExtArrayNodeSet(1);
set.add(node);
final XmldbURI[] docs = new XmldbURI[]{node.getOwnerDocument().getURI()};
return execute(broker, transaction, docs, set, expression, null);
}
});
}
private ResourceSet execute(final DBBroker broker, final Txn transaction, XmldbURI[] docs, final Sequence contextSet, final CompiledExpression expression, final String sortExpr) throws XMLDBException {
final long start = System.currentTimeMillis();
final CompiledXQuery expr = (CompiledXQuery)expression;
Sequence result = null;
final XQueryContext context = expr.getContext();
try {
context.setStaticallyKnownDocuments(docs);
if (lockedDocuments != null) {
context.setProtectedDocs(lockedDocuments);
}
setupContext(null, context);
final XQuery xquery = brokerPool.getXQueryService();
result = xquery.execute(broker, expr, contextSet, properties);
} catch (final Exception e) {
// need to catch all runtime exceptions here to be able to release locked documents
throw new XMLDBException(ErrorCodes.VENDOR_ERROR, e.getMessage(), e);
} finally {
/*
* Run the cleanup tasks, but don't close BinaryValues which
* are in the result set as the user has not yet accessed them.
*
* Final cleanup of those BinaryValues is done by the user
* calling EXistResource#close(), ResourceSet#clear() or CompiledExpression#reset().
*/
final Sequence resSeq = result;
context.runCleanupTasks(o -> {
if(resSeq != null && o instanceof BinaryValue) {
for(int i = 0; i < resSeq.getItemCount(); i++) {
if (resSeq.itemAt(i) == o) {
return false;
}
}
}
return true;
});
}
LOG.debug("query took " + (System.currentTimeMillis() - start) + " ms.");
if(result != null) {
final Properties resourceSetProperties = new Properties(properties);
resourceSetProperties.setProperty(EXistOutputKeys.XDM_SERIALIZATION, "yes");
return new LocalResourceSet(user, brokerPool, collection, resourceSetProperties, result, sortExpr);
} else {
return null;
}
}
@Override
public ResourceSet execute(final Source source) throws XMLDBException {
return execute((broker, transaction) -> source);
}
@Override
public ResourceSet executeStoredQuery(final String uri) throws XMLDBException {
return execute((broker, transaction) -> {
final DocumentImpl resource = broker.getResource(new XmldbURI(uri), Permission.READ | Permission.EXECUTE);
if (resource == null) {
throw new XMLDBException(ErrorCodes.INVALID_URI, "No stored XQuery exists at: " + uri);
}
return new DBSource(broker, (BinaryDocument) resource, false);
});
}
private ResourceSet execute(final LocalXmldbFunction sourceOp) throws XMLDBException {
return withDb((broker, transaction) -> {
final long start = System.currentTimeMillis();
final Source source = sourceOp.apply(broker, transaction);
final XmldbURI[] docs = new XmldbURI[]{XmldbURI.create(collection.getName(broker, transaction))};
final XQuery xquery = brokerPool.getXQueryService();
final XQueryPool pool = brokerPool.getXQueryPool();
XQueryContext context;
CompiledXQuery compiled = pool.borrowCompiledXQuery(broker, source);
if (compiled == null) {
context = new XQueryContext(broker.getBrokerPool());
} else {
context = compiled.getContext();
context.prepareForReuse();
}
context.setStaticallyKnownDocuments(docs);
if (variableDecls.containsKey(Debuggee.PREFIX + ":session")) {
context.declareVariable(Debuggee.SESSION, variableDecls.get(Debuggee.PREFIX + ":session"));
variableDecls.remove(Debuggee.PREFIX + ":session");
}
setupContext(source, context);
if (compiled == null) {
compiled = xquery.compile(broker, context, source);
}
try {
final Sequence result = xquery.execute(broker, compiled, null, properties);
if(LOG.isDebugEnabled()) {
LOG.debug("query took " + (System.currentTimeMillis() - start) + " ms.");
}
final Properties resourceSetProperties = new Properties(properties);
resourceSetProperties.setProperty(EXistOutputKeys.XDM_SERIALIZATION, "yes");
return result != null ? new LocalResourceSet(user, brokerPool, collection, resourceSetProperties, result, null) : null;
} finally {
compiled.getContext().runCleanupTasks();
pool.returnCompiledXQuery(source, compiled);
}
});
}
@Override
public CompiledExpression compile(final String query) throws XMLDBException {
return withDb((broker, transaction) -> {
final Either maybeExpr = compileAndCheck(broker, transaction, query);
if(maybeExpr.isLeft()) {
final XPathException e = maybeExpr.left().get();
throw new XMLDBException(ErrorCodes.VENDOR_ERROR, e.getMessage(), e);
} else {
return maybeExpr.right().get();
}
});
}
@Override
public CompiledExpression compileAndCheck(final String query) throws XMLDBException, XPathException {
final Either result = withDb((broker, transaction) -> compileAndCheck(broker, transaction, query));
if(result.isLeft()) {
throw result.left().get();
} else {
return result.right().get();
}
}
private Either compileAndCheck(final DBBroker broker, final Txn transaction, final String query) throws XMLDBException {
final long start = System.currentTimeMillis();
final XQuery xquery = broker.getBrokerPool().getXQueryService();
final XQueryContext context = new XQueryContext(broker.getBrokerPool());
try {
setupContext(null, context);
final CompiledExpression expr = xquery.compile(broker, context, query);
if(LOG.isDebugEnabled()) {
LOG.debug("compilation took " + (System.currentTimeMillis() - start));
}
return Either.Right(expr);
} catch (final PermissionDeniedException e) {
throw new XMLDBException(ErrorCodes.PERMISSION_DENIED, e.getMessage(), e);
} catch(final IllegalArgumentException e) {
throw new XMLDBException(ErrorCodes.VENDOR_ERROR, e.getMessage(), e);
} catch(final XPathException e) {
return Either.Left(e);
}
}
@Override
public ResourceSet queryResource(final String resource, final String query) throws XMLDBException {
return withDb((broker, transaction) -> {
final LocalXMLResource res = (LocalXMLResource) collection.getResource(broker, transaction, resource);
if (res == null) {
throw new XMLDBException(ErrorCodes.INVALID_RESOURCE, "resource '" + resource + "' not found");
}
final XmldbURI[] docs = new XmldbURI[]{ getCollectionUri(broker, transaction, res.getParentCollection()).append(res.getDocumentId()) };
return doQuery(broker, transaction, query, docs, null, null);
});
}
protected void setupContext(final Source source, final XQueryContext context) throws XMLDBException, XPathException {
try {
context.setBaseURI(new AnyURIValue(properties.getProperty("base-uri", collection.getPath())));
} catch(final XPathException e) {
throw new XMLDBException(ErrorCodes.INVALID_URI,"Invalid base uri",e);
}
if(moduleLoadPath != null) {
context.setModuleLoadPath(moduleLoadPath);
} else if (source != null) {
String modulePath = null;
if (source instanceof DBSource) {
modulePath = ((DBSource) source).getDocumentPath().removeLastSegment().toString();
} else if (source instanceof FileSource) {
modulePath = ((FileSource) source).getPath().getParent().toString();
}
if (modulePath != null) {
context.setModuleLoadPath(modulePath);
}
}
// declare namespace/prefix mappings
for (final Map.Entry entry : namespaceDecls.entrySet()) {
context.declareNamespace(entry.getKey(), entry.getValue());
}
// declare static variables
for (final Map.Entry entry : variableDecls.entrySet()) {
context.declareVariable(entry.getKey(), entry.getValue());
}
}
/**
* Execute all following queries in a protected environment.
* Protected means: it is guaranteed that documents referenced by the
* query or the result set are not modified by other threads
* until {@link #endProtected} is called.
*/
@Override
public void beginProtected() throws XMLDBException {
try {
int retries = BEGIN_PROTECTED_MAX_LOCKING_RETRIES == - 1 ? -1 : BEGIN_PROTECTED_MAX_LOCKING_RETRIES - 2;
boolean deadlockCaught;
do {
reservedBroker = brokerPool.get(Optional.of(user));
deadlockCaught = false;
MutableDocumentSet docs = null;
try {
final org.exist.collections.Collection coll = reservedBroker.getCollection(collection.getPathURI());
lockedDocuments = new LockedDocumentMap();
docs = new DefaultDocumentSet();
coll.allDocs(reservedBroker, docs, true, lockedDocuments, LockMode.WRITE_LOCK);
return;
} catch (final LockException e) {
LOG.warn("Deadlock detected. Starting over again. Docs: {}; locked: {}. Cause: {}", docs.getDocumentCount(), lockedDocuments.size(), e.getMessage());
lockedDocuments.unlock();
reservedBroker.close();
deadlockCaught = true;
} catch (final PermissionDeniedException e) {
throw new XMLDBException(ErrorCodes.PERMISSION_DENIED,
"Permission denied on document");
}
retries--;
} while (deadlockCaught && retries >= -1);
} catch (final EXistException e) {
if(reservedBroker != null) {
reservedBroker.close();
}
throw new XMLDBException(ErrorCodes.VENDOR_ERROR, e.getMessage());
}
throw new XMLDBException(ErrorCodes.VENDOR_ERROR, "Unable to beginProtected after " + BEGIN_PROTECTED_MAX_LOCKING_RETRIES + " retries");
}
/**
* Close the protected environment. All locks held
* by the current thread are released. The result set
* is no longer guaranteed to be stable.
*/
@Override
public void endProtected() {
lockDocuments = false;
if(lockedDocuments != null) {
lockedDocuments.unlock();
}
lockedDocuments = null;
if (reservedBroker != null) {
reservedBroker.close();
}
reservedBroker = null;
}
@Override
public void removeNamespace(final String ns) throws XMLDBException {
for (final Iterator i = namespaceDecls.values().iterator(); i.hasNext();) {
if (i.next().equals(ns)) {
i.remove();
}
}
}
@Override
public void setCollection(final Collection col) throws XMLDBException {
}
@Override
public void setNamespace(final String prefix, final String namespace) throws XMLDBException {
namespaceDecls.put(prefix, namespace);
}
@Override
public void setProperty(final String property, final String value) throws XMLDBException {
properties.setProperty(property, value);
}
@Override
public void declareVariable(final String qname, final Object initialValue) throws XMLDBException {
variableDecls.put(qname, initialValue);
}
@Override
public void clearVariables() throws XMLDBException {
variableDecls.clear();
}
@Override
public void setXPathCompatibility(final boolean backwardsCompatible) {
this.xpathCompatible = backwardsCompatible;
}
@Override
public void setModuleLoadPath(final String path) {
moduleLoadPath = path;
}
@Override
public void dump(final CompiledExpression expression, final Writer writer) throws XMLDBException {
final CompiledXQuery expr = (CompiledXQuery)expression;
expr.dump(writer);
}
}
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