org.apache.activemq.store.kahadb.disk.journal.Journal Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of activemq-osgi Show documentation
Show all versions of activemq-osgi Show documentation
Puts together an ActiveMQ OSGi bundle
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq.store.kahadb.disk.journal;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.zip.Adler32;
import java.util.zip.Checksum;
import org.apache.activemq.store.kahadb.disk.util.LinkedNode;
import org.apache.activemq.util.IOHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.activemq.util.ByteSequence;
import org.apache.activemq.util.DataByteArrayInputStream;
import org.apache.activemq.util.DataByteArrayOutputStream;
import org.apache.activemq.store.kahadb.disk.util.LinkedNodeList;
import org.apache.activemq.store.kahadb.disk.util.SchedulerTimerTask;
import org.apache.activemq.store.kahadb.disk.util.Sequence;
/**
* Manages DataFiles
*
*
*/
public class Journal {
public static final String CALLER_BUFFER_APPENDER = "org.apache.kahadb.journal.CALLER_BUFFER_APPENDER";
public static final boolean callerBufferAppender = Boolean.parseBoolean(System.getProperty(CALLER_BUFFER_APPENDER, "false"));
private static final int MAX_BATCH_SIZE = 32*1024*1024;
// ITEM_HEAD_SPACE = length + type+ reserved space + SOR
public static final int RECORD_HEAD_SPACE = 4 + 1;
public static final byte USER_RECORD_TYPE = 1;
public static final byte BATCH_CONTROL_RECORD_TYPE = 2;
// Batch Control Item holds a 4 byte size of the batch and a 8 byte checksum of the batch.
public static final byte[] BATCH_CONTROL_RECORD_MAGIC = bytes("WRITE BATCH");
public static final int BATCH_CONTROL_RECORD_SIZE = RECORD_HEAD_SPACE+BATCH_CONTROL_RECORD_MAGIC.length+4+8;
public static final byte[] BATCH_CONTROL_RECORD_HEADER = createBatchControlRecordHeader();
private static byte[] createBatchControlRecordHeader() {
try {
DataByteArrayOutputStream os = new DataByteArrayOutputStream();
os.writeInt(BATCH_CONTROL_RECORD_SIZE);
os.writeByte(BATCH_CONTROL_RECORD_TYPE);
os.write(BATCH_CONTROL_RECORD_MAGIC);
ByteSequence sequence = os.toByteSequence();
sequence.compact();
return sequence.getData();
} catch (IOException e) {
throw new RuntimeException("Could not create batch control record header.", e);
}
}
public static final String DEFAULT_DIRECTORY = ".";
public static final String DEFAULT_ARCHIVE_DIRECTORY = "data-archive";
public static final String DEFAULT_FILE_PREFIX = "db-";
public static final String DEFAULT_FILE_SUFFIX = ".log";
public static final int DEFAULT_MAX_FILE_LENGTH = 1024 * 1024 * 32;
public static final int DEFAULT_CLEANUP_INTERVAL = 1000 * 30;
public static final int PREFERED_DIFF = 1024 * 512;
public static final int DEFAULT_MAX_WRITE_BATCH_SIZE = 1024 * 1024 * 4;
private static final Logger LOG = LoggerFactory.getLogger(Journal.class);
protected final Map inflightWrites = new ConcurrentHashMap();
protected File directory = new File(DEFAULT_DIRECTORY);
protected File directoryArchive;
private boolean directoryArchiveOverridden = false;
protected String filePrefix = DEFAULT_FILE_PREFIX;
protected String fileSuffix = DEFAULT_FILE_SUFFIX;
protected boolean started;
protected int maxFileLength = DEFAULT_MAX_FILE_LENGTH;
protected int preferedFileLength = DEFAULT_MAX_FILE_LENGTH - PREFERED_DIFF;
protected int writeBatchSize = DEFAULT_MAX_WRITE_BATCH_SIZE;
protected FileAppender appender;
protected DataFileAccessorPool accessorPool;
protected Map fileMap = new HashMap();
protected Map fileByFileMap = new LinkedHashMap();
protected LinkedNodeList dataFiles = new LinkedNodeList();
protected final AtomicReference lastAppendLocation = new AtomicReference();
protected Runnable cleanupTask;
protected AtomicLong totalLength = new AtomicLong();
protected boolean archiveDataLogs;
private ReplicationTarget replicationTarget;
protected boolean checksum;
protected boolean checkForCorruptionOnStartup;
protected boolean enableAsyncDiskSync = true;
private Timer timer;
public interface DataFileRemovedListener {
void fileRemoved(DataFile datafile);
}
private DataFileRemovedListener dataFileRemovedListener;
public synchronized void start() throws IOException {
if (started) {
return;
}
long start = System.currentTimeMillis();
accessorPool = new DataFileAccessorPool(this);
started = true;
preferedFileLength = Math.max(PREFERED_DIFF, getMaxFileLength() - PREFERED_DIFF);
appender = callerBufferAppender ? new CallerBufferingDataFileAppender(this) : new DataFileAppender(this);
File[] files = directory.listFiles(new FilenameFilter() {
public boolean accept(File dir, String n) {
return dir.equals(directory) && n.startsWith(filePrefix) && n.endsWith(fileSuffix);
}
});
if (files != null) {
for (File file : files) {
try {
String n = file.getName();
String numStr = n.substring(filePrefix.length(), n.length()-fileSuffix.length());
int num = Integer.parseInt(numStr);
DataFile dataFile = new DataFile(file, num, preferedFileLength);
fileMap.put(dataFile.getDataFileId(), dataFile);
totalLength.addAndGet(dataFile.getLength());
} catch (NumberFormatException e) {
// Ignore file that do not match the pattern.
}
}
// Sort the list so that we can link the DataFiles together in the
// right order.
List l = new ArrayList(fileMap.values());
Collections.sort(l);
for (DataFile df : l) {
if (df.getLength() == 0) {
// possibly the result of a previous failed write
LOG.info("ignoring zero length, partially initialised journal data file: " + df);
continue;
}
dataFiles.addLast(df);
fileByFileMap.put(df.getFile(), df);
if( isCheckForCorruptionOnStartup() ) {
lastAppendLocation.set(recoveryCheck(df));
}
}
}
getCurrentWriteFile();
if( lastAppendLocation.get()==null ) {
DataFile df = dataFiles.getTail();
lastAppendLocation.set(recoveryCheck(df));
}
cleanupTask = new Runnable() {
public void run() {
cleanup();
}
};
this.timer = new Timer("KahaDB Scheduler", true);
TimerTask task = new SchedulerTimerTask(cleanupTask);
this.timer.scheduleAtFixedRate(task, DEFAULT_CLEANUP_INTERVAL,DEFAULT_CLEANUP_INTERVAL);
long end = System.currentTimeMillis();
LOG.trace("Startup took: "+(end-start)+" ms");
}
private static byte[] bytes(String string) {
try {
return string.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
protected Location recoveryCheck(DataFile dataFile) throws IOException {
Location location = new Location();
location.setDataFileId(dataFile.getDataFileId());
location.setOffset(0);
DataFileAccessor reader = accessorPool.openDataFileAccessor(dataFile);
try {
while( true ) {
int size = checkBatchRecord(reader, location.getOffset());
if ( size>=0 ) {
location.setOffset(location.getOffset()+BATCH_CONTROL_RECORD_SIZE+size);
} else {
// Perhaps it's just some corruption... scan through the file to find the next valid batch record. We
// may have subsequent valid batch records.
int nextOffset = findNextBatchRecord(reader, location.getOffset()+1);
if( nextOffset >=0 ) {
Sequence sequence = new Sequence(location.getOffset(), nextOffset - 1);
LOG.info("Corrupt journal records found in '"+dataFile.getFile()+"' between offsets: "+sequence);
dataFile.corruptedBlocks.add(sequence);
location.setOffset(nextOffset);
} else {
break;
}
}
}
} catch (IOException e) {
} finally {
accessorPool.closeDataFileAccessor(reader);
}
int existingLen = dataFile.getLength();
dataFile.setLength(location.getOffset());
if (existingLen > dataFile.getLength()) {
totalLength.addAndGet(dataFile.getLength() - existingLen);
}
if( !dataFile.corruptedBlocks.isEmpty() ) {
// Is the end of the data file corrupted?
if( dataFile.corruptedBlocks.getTail().getLast()+1 == location.getOffset() ) {
dataFile.setLength((int) dataFile.corruptedBlocks.removeLastSequence().getFirst());
}
}
return location;
}
private int findNextBatchRecord(DataFileAccessor reader, int offset) throws IOException {
ByteSequence header = new ByteSequence(BATCH_CONTROL_RECORD_HEADER);
byte data[] = new byte[1024*4];
ByteSequence bs = new ByteSequence(data, 0, reader.read(offset, data));
int pos = 0;
while( true ) {
pos = bs.indexOf(header, pos);
if( pos >= 0 ) {
return offset+pos;
} else {
// need to load the next data chunck in..
if( bs.length != data.length ) {
// If we had a short read then we were at EOF
return -1;
}
offset += bs.length-BATCH_CONTROL_RECORD_HEADER.length;
bs = new ByteSequence(data, 0, reader.read(offset, data));
pos=0;
}
}
}
public int checkBatchRecord(DataFileAccessor reader, int offset) throws IOException {
byte controlRecord[] = new byte[BATCH_CONTROL_RECORD_SIZE];
DataByteArrayInputStream controlIs = new DataByteArrayInputStream(controlRecord);
reader.readFully(offset, controlRecord);
// Assert that it's a batch record.
for( int i=0; i < BATCH_CONTROL_RECORD_HEADER.length; i++ ) {
if( controlIs.readByte() != BATCH_CONTROL_RECORD_HEADER[i] ) {
return -1;
}
}
int size = controlIs.readInt();
if( size > MAX_BATCH_SIZE ) {
return -1;
}
if( isChecksum() ) {
long expectedChecksum = controlIs.readLong();
if( expectedChecksum == 0 ) {
// Checksuming was not enabled when the record was stored.
// we can't validate the record :(
return size;
}
byte data[] = new byte[size];
reader.readFully(offset+BATCH_CONTROL_RECORD_SIZE, data);
Checksum checksum = new Adler32();
checksum.update(data, 0, data.length);
if( expectedChecksum!=checksum.getValue() ) {
return -1;
}
}
return size;
}
void addToTotalLength(int size) {
totalLength.addAndGet(size);
}
public long length() {
return totalLength.get();
}
synchronized DataFile getCurrentWriteFile() throws IOException {
if (dataFiles.isEmpty()) {
rotateWriteFile();
}
return dataFiles.getTail();
}
synchronized DataFile rotateWriteFile() {
int nextNum = !dataFiles.isEmpty() ? dataFiles.getTail().getDataFileId().intValue() + 1 : 1;
File file = getFile(nextNum);
DataFile nextWriteFile = new DataFile(file, nextNum, preferedFileLength);
// actually allocate the disk space
fileMap.put(nextWriteFile.getDataFileId(), nextWriteFile);
fileByFileMap.put(file, nextWriteFile);
dataFiles.addLast(nextWriteFile);
return nextWriteFile;
}
public File getFile(int nextNum) {
String fileName = filePrefix + nextNum + fileSuffix;
File file = new File(directory, fileName);
return file;
}
synchronized DataFile getDataFile(Location item) throws IOException {
Integer key = Integer.valueOf(item.getDataFileId());
DataFile dataFile = fileMap.get(key);
if (dataFile == null) {
LOG.error("Looking for key " + key + " but not found in fileMap: " + fileMap);
throw new IOException("Could not locate data file " + getFile(item.getDataFileId()));
}
return dataFile;
}
synchronized File getFile(Location item) throws IOException {
Integer key = Integer.valueOf(item.getDataFileId());
DataFile dataFile = fileMap.get(key);
if (dataFile == null) {
LOG.error("Looking for key " + key + " but not found in fileMap: " + fileMap);
throw new IOException("Could not locate data file " + getFile(item.getDataFileId()));
}
return dataFile.getFile();
}
private DataFile getNextDataFile(DataFile dataFile) {
return dataFile.getNext();
}
public synchronized void close() throws IOException {
if (!started) {
return;
}
if (this.timer != null) {
this.timer.cancel();
}
accessorPool.close();
appender.close();
fileMap.clear();
fileByFileMap.clear();
dataFiles.clear();
lastAppendLocation.set(null);
started = false;
}
protected synchronized void cleanup() {
if (accessorPool != null) {
accessorPool.disposeUnused();
}
}
public synchronized boolean delete() throws IOException {
// Close all open file handles...
appender.close();
accessorPool.close();
boolean result = true;
for (Iterator i = fileMap.values().iterator(); i.hasNext();) {
DataFile dataFile = i.next();
totalLength.addAndGet(-dataFile.getLength());
result &= dataFile.delete();
}
fileMap.clear();
fileByFileMap.clear();
lastAppendLocation.set(null);
dataFiles = new LinkedNodeList();
// reopen open file handles...
accessorPool = new DataFileAccessorPool(this);
appender = new DataFileAppender(this);
return result;
}
public synchronized void removeDataFiles(Set files) throws IOException {
for (Integer key : files) {
// Can't remove the data file (or subsequent files) that is currently being written to.
if( key >= lastAppendLocation.get().getDataFileId() ) {
continue;
}
DataFile dataFile = fileMap.get(key);
if( dataFile!=null ) {
forceRemoveDataFile(dataFile);
}
}
}
private synchronized void forceRemoveDataFile(DataFile dataFile) throws IOException {
accessorPool.disposeDataFileAccessors(dataFile);
fileByFileMap.remove(dataFile.getFile());
fileMap.remove(dataFile.getDataFileId());
totalLength.addAndGet(-dataFile.getLength());
dataFile.unlink();
if (archiveDataLogs) {
File directoryArchive = getDirectoryArchive();
if (directoryArchive.exists()) {
LOG.debug("Archive directory exists: {}", directoryArchive);
} else {
if (directoryArchive.isAbsolute())
if (LOG.isDebugEnabled()) {
LOG.debug("Archive directory [{}] does not exist - creating it now",
directoryArchive.getAbsolutePath());
}
IOHelper.mkdirs(directoryArchive);
}
LOG.debug("Moving data file {} to {} ", dataFile, directoryArchive.getCanonicalPath());
dataFile.move(directoryArchive);
LOG.debug("Successfully moved data file");
} else {
LOG.debug("Deleting data file: {}", dataFile);
if ( dataFile.delete() ) {
LOG.debug("Discarded data file: {}", dataFile);
} else {
LOG.warn("Failed to discard data file : {}", dataFile.getFile());
}
}
if (dataFileRemovedListener != null) {
dataFileRemovedListener.fileRemoved(dataFile);
}
}
/**
* @return the maxFileLength
*/
public int getMaxFileLength() {
return maxFileLength;
}
/**
* @param maxFileLength the maxFileLength to set
*/
public void setMaxFileLength(int maxFileLength) {
this.maxFileLength = maxFileLength;
}
@Override
public String toString() {
return directory.toString();
}
public synchronized void appendedExternally(Location loc, int length) throws IOException {
DataFile dataFile = null;
if( dataFiles.getTail().getDataFileId() == loc.getDataFileId() ) {
// It's an update to the current log file..
dataFile = dataFiles.getTail();
dataFile.incrementLength(length);
} else if( dataFiles.getTail().getDataFileId()+1 == loc.getDataFileId() ) {
// It's an update to the next log file.
int nextNum = loc.getDataFileId();
File file = getFile(nextNum);
dataFile = new DataFile(file, nextNum, preferedFileLength);
// actually allocate the disk space
fileMap.put(dataFile.getDataFileId(), dataFile);
fileByFileMap.put(file, dataFile);
dataFiles.addLast(dataFile);
} else {
throw new IOException("Invalid external append.");
}
}
public synchronized Location getNextLocation(Location location) throws IOException, IllegalStateException {
Location cur = null;
while (true) {
if (cur == null) {
if (location == null) {
DataFile head = dataFiles.getHead();
if( head == null ) {
return null;
}
cur = new Location();
cur.setDataFileId(head.getDataFileId());
cur.setOffset(0);
} else {
// Set to the next offset..
if (location.getSize() == -1) {
cur = new Location(location);
} else {
cur = new Location(location);
cur.setOffset(location.getOffset() + location.getSize());
}
}
} else {
cur.setOffset(cur.getOffset() + cur.getSize());
}
DataFile dataFile = getDataFile(cur);
// Did it go into the next file??
if (dataFile.getLength() <= cur.getOffset()) {
dataFile = getNextDataFile(dataFile);
if (dataFile == null) {
return null;
} else {
cur.setDataFileId(dataFile.getDataFileId().intValue());
cur.setOffset(0);
}
}
// Load in location size and type.
DataFileAccessor reader = accessorPool.openDataFileAccessor(dataFile);
try {
reader.readLocationDetails(cur);
} finally {
accessorPool.closeDataFileAccessor(reader);
}
if (cur.getType() == 0) {
return null;
} else if (cur.getType() == USER_RECORD_TYPE) {
// Only return user records.
return cur;
}
}
}
public synchronized Location getNextLocation(File file, Location lastLocation, boolean thisFileOnly) throws IllegalStateException, IOException {
DataFile df = fileByFileMap.get(file);
return getNextLocation(df, lastLocation, thisFileOnly);
}
public synchronized Location getNextLocation(DataFile dataFile, Location lastLocation, boolean thisFileOnly) throws IOException, IllegalStateException {
Location cur = null;
while (true) {
if (cur == null) {
if (lastLocation == null) {
DataFile head = dataFile.getHeadNode();
cur = new Location();
cur.setDataFileId(head.getDataFileId());
cur.setOffset(0);
} else {
// Set to the next offset..
cur = new Location(lastLocation);
cur.setOffset(cur.getOffset() + cur.getSize());
}
} else {
cur.setOffset(cur.getOffset() + cur.getSize());
}
// Did it go into the next file??
if (dataFile.getLength() <= cur.getOffset()) {
if (thisFileOnly) {
return null;
} else {
dataFile = getNextDataFile(dataFile);
if (dataFile == null) {
return null;
} else {
cur.setDataFileId(dataFile.getDataFileId().intValue());
cur.setOffset(0);
}
}
}
// Load in location size and type.
DataFileAccessor reader = accessorPool.openDataFileAccessor(dataFile);
try {
reader.readLocationDetails(cur);
} finally {
accessorPool.closeDataFileAccessor(reader);
}
if (cur.getType() == 0) {
return null;
} else if (cur.getType() > 0) {
// Only return user records.
return cur;
}
}
}
public synchronized ByteSequence read(Location location) throws IOException, IllegalStateException {
DataFile dataFile = getDataFile(location);
DataFileAccessor reader = accessorPool.openDataFileAccessor(dataFile);
ByteSequence rc = null;
try {
rc = reader.readRecord(location);
} finally {
accessorPool.closeDataFileAccessor(reader);
}
return rc;
}
public Location write(ByteSequence data, boolean sync) throws IOException, IllegalStateException {
Location loc = appender.storeItem(data, Location.USER_TYPE, sync);
return loc;
}
public Location write(ByteSequence data, Runnable onComplete) throws IOException, IllegalStateException {
Location loc = appender.storeItem(data, Location.USER_TYPE, onComplete);
return loc;
}
public void update(Location location, ByteSequence data, boolean sync) throws IOException {
DataFile dataFile = getDataFile(location);
DataFileAccessor updater = accessorPool.openDataFileAccessor(dataFile);
try {
updater.updateRecord(location, data, sync);
} finally {
accessorPool.closeDataFileAccessor(updater);
}
}
public File getDirectory() {
return directory;
}
public void setDirectory(File directory) {
this.directory = directory;
}
public String getFilePrefix() {
return filePrefix;
}
public void setFilePrefix(String filePrefix) {
this.filePrefix = filePrefix;
}
public Map getInflightWrites() {
return inflightWrites;
}
public Location getLastAppendLocation() {
return lastAppendLocation.get();
}
public void setLastAppendLocation(Location lastSyncedLocation) {
this.lastAppendLocation.set(lastSyncedLocation);
}
public File getDirectoryArchive() {
if (!directoryArchiveOverridden && (directoryArchive == null)) {
// create the directoryArchive relative to the journal location
directoryArchive = new File(directory.getAbsolutePath() +
File.separator + DEFAULT_ARCHIVE_DIRECTORY);
}
return directoryArchive;
}
public void setDirectoryArchive(File directoryArchive) {
directoryArchiveOverridden = true;
this.directoryArchive = directoryArchive;
}
public boolean isArchiveDataLogs() {
return archiveDataLogs;
}
public void setArchiveDataLogs(boolean archiveDataLogs) {
this.archiveDataLogs = archiveDataLogs;
}
synchronized public Integer getCurrentDataFileId() {
if (dataFiles.isEmpty())
return null;
return dataFiles.getTail().getDataFileId();
}
/**
* Get a set of files - only valid after start()
*
* @return files currently being used
*/
public Set getFiles() {
return fileByFileMap.keySet();
}
public synchronized Map getFileMap() {
return new TreeMap(fileMap);
}
public long getDiskSize() {
long tailLength=0;
synchronized( this ) {
if( !dataFiles.isEmpty() ) {
tailLength = dataFiles.getTail().getLength();
}
}
long rc = totalLength.get();
// The last file is actually at a minimum preferedFileLength big.
if( tailLength < preferedFileLength ) {
rc -= tailLength;
rc += preferedFileLength;
}
return rc;
}
public void setReplicationTarget(ReplicationTarget replicationTarget) {
this.replicationTarget = replicationTarget;
}
public ReplicationTarget getReplicationTarget() {
return replicationTarget;
}
public String getFileSuffix() {
return fileSuffix;
}
public void setFileSuffix(String fileSuffix) {
this.fileSuffix = fileSuffix;
}
public boolean isChecksum() {
return checksum;
}
public void setChecksum(boolean checksumWrites) {
this.checksum = checksumWrites;
}
public boolean isCheckForCorruptionOnStartup() {
return checkForCorruptionOnStartup;
}
public void setCheckForCorruptionOnStartup(boolean checkForCorruptionOnStartup) {
this.checkForCorruptionOnStartup = checkForCorruptionOnStartup;
}
public void setWriteBatchSize(int writeBatchSize) {
this.writeBatchSize = writeBatchSize;
}
public int getWriteBatchSize() {
return writeBatchSize;
}
public void setSizeAccumulator(AtomicLong storeSizeAccumulator) {
this.totalLength = storeSizeAccumulator;
}
public void setEnableAsyncDiskSync(boolean val) {
this.enableAsyncDiskSync = val;
}
public boolean isEnableAsyncDiskSync() {
return enableAsyncDiskSync;
}
public void setDataFileRemovedListener(DataFileRemovedListener dataFileRemovedListener) {
this.dataFileRemovedListener = dataFileRemovedListener;
}
public static class WriteCommand extends LinkedNode {
public final Location location;
public final ByteSequence data;
final boolean sync;
public final Runnable onComplete;
public WriteCommand(Location location, ByteSequence data, boolean sync) {
this.location = location;
this.data = data;
this.sync = sync;
this.onComplete = null;
}
public WriteCommand(Location location, ByteSequence data, Runnable onComplete) {
this.location = location;
this.data = data;
this.onComplete = onComplete;
this.sync = false;
}
}
public static class WriteKey {
private final int file;
private final long offset;
private final int hash;
public WriteKey(Location item) {
file = item.getDataFileId();
offset = item.getOffset();
// TODO: see if we can build a better hash
hash = (int)(file ^ offset);
}
public int hashCode() {
return hash;
}
public boolean equals(Object obj) {
if (obj instanceof WriteKey) {
WriteKey di = (WriteKey)obj;
return di.file == file && di.offset == offset;
}
return false;
}
}
}