/*
* Copyright (C) 2006-2013 Bitronix Software (http://www.bitronix.be)
*
* Licensed 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 bitronix.tm.journal;
import bitronix.tm.utils.Uid;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.transaction.Status;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Used to write {@link TransactionLogRecord} objects to a log file.
*
* @author Ludovic Orban
* @author Brett Wooldridge
*/
public class TransactionLogAppender {
private final static Logger log = LoggerFactory.getLogger(TransactionLogAppender.class);
/**
* int-encoded "xntB" ASCII string.
* This will be useful after swapping log files since we will potentially overwrite old logs not necessarily of the
* same size. Very useful when debugging and eventually restoring broken log files.
*/
public static final int END_RECORD = 0x786e7442;
private final File file;
private final RandomAccessFile randomeAccessFile;
private final FileChannel fc;
private final FileLock lock;
private final TransactionLogHeader header;
private final long maxFileLength;
private final AtomicInteger outstandingWrites;
private final HashMap<Uid, Set<String>> danglingRecords;
private long position;
/**
* Create an appender that will write to specified file up to the specified maximum length.
* @param file the underlying File used to write to disk.
* @param maxFileLength size of the file on disk that can never be bypassed.
* @throws IOException if an I/O error occurs.
*/
public TransactionLogAppender(File file, long maxFileLength) throws IOException {
this.file = file;
this.randomeAccessFile = new RandomAccessFile(file, "rw");
this.fc = randomeAccessFile.getChannel();
this.header = new TransactionLogHeader(fc, maxFileLength);
this.maxFileLength = maxFileLength;
this.lock = fc.tryLock(0, TransactionLogHeader.TIMESTAMP_HEADER, false);
if (this.lock == null)
throw new IOException("transaction log file " + file.getName() + " is locked. Is another instance already running?");
this.outstandingWrites = new AtomicInteger();
this.danglingRecords = new HashMap<Uid, Set<String>>();
this.position = header.getPosition();
}
/**
* Get the current file position and advance the position by recordSize if
* the maximum file length won't be exceeded. Callers to this method are
* synchronized within the DiskJournal and it is guaranteed there will
* never be two callers to this method. This creates a Java memory barrier
* that guarantees that 'position' will never be viewed inconsistently
* between threads.
*
* @param tlog the TransactionLogRecord
* @return true if the log should rollover, false otherwise
* @throws IOException if an I/O error occurs
*/
protected boolean setPositionAndAdvance(TransactionLogRecord tlog) throws IOException {
int tlogSize = tlog.calculateTotalRecordSize();
if (position + tlogSize > maxFileLength) {
return true;
}
long writePosition = position;
position += tlogSize;
tlog.setWritePosition(writePosition);
outstandingWrites.incrementAndGet();
return false;
}
/**
* Write a {@link TransactionLogRecord} to disk.
* @param tlog the record to write to disk.
* @throws IOException if an I/O error occurs.
*/
protected void writeLog(TransactionLogRecord tlog) throws IOException {
try {
int status = tlog.getStatus();
Uid gtrid = tlog.getGtrid();
int recordSize = tlog.calculateTotalRecordSize();
ByteBuffer buf = ByteBuffer.allocate(recordSize);
buf.putInt(tlog.getStatus());
buf.putInt(tlog.getRecordLength());
buf.putInt(tlog.getHeaderLength());
buf.putLong(tlog.getTime());
buf.putInt(tlog.getSequenceNumber());
buf.putInt(tlog.getCrc32());
buf.put((byte) gtrid.getArray().length);
buf.put(gtrid.getArray());
Set<String> uniqueNames = tlog.getUniqueNames();
buf.putInt(uniqueNames.size());
for (String uniqueName : uniqueNames) {
buf.putShort((short) uniqueName.length());
buf.put(uniqueName.getBytes());
}
buf.putInt(tlog.getEndRecord());
buf.flip();
if (log.isDebugEnabled()) { log.debug("between " + tlog.getWritePosition() + " and " + tlog.getWritePosition() + tlog.calculateTotalRecordSize() + ", writing " + tlog); }
final long writePosition = tlog.getWritePosition();
while (buf.hasRemaining()) {
fc.write(buf, writePosition + buf.position());
}
trackOutstanding(status, gtrid, uniqueNames);
}
finally {
if (outstandingWrites.decrementAndGet() == 0) {
header.setPosition(position);
}
}
}
protected List<TransactionLogRecord> getDanglingLogs() {
synchronized (danglingRecords) {
List<Uid> sortedUids = new ArrayList<Uid>(danglingRecords.keySet());
Collections.sort(sortedUids, new Comparator<Uid>() {
public int compare(Uid uid1, Uid uid2) {
return Integer.valueOf(uid1.extractSequence()).compareTo(uid2.extractSequence());
}
});
List<TransactionLogRecord> outstandingLogs = new ArrayList<TransactionLogRecord>(danglingRecords.size());
for (Uid uid : sortedUids) {
Set<String> uniqueNames = danglingRecords.get(uid);
outstandingLogs.add(new TransactionLogRecord(Status.STATUS_COMMITTING, uid, uniqueNames));
}
return outstandingLogs;
}
}
protected void clearDanglingLogs() {
synchronized (danglingRecords) {
danglingRecords.clear();
}
}
/**
* This method tracks outstanding (uncommitted) resources by gtrid. Access
* to the danglingRecords map, and the TreeSets contained within are guarded
* by a synchronization lock on danglingRecords itself.
*
* @param status the transaction log record status
* @param gtrid the transaction id
* @param uniqueNames the set of uniquely named resources
*/
private void trackOutstanding(int status, Uid gtrid, Set<String> uniqueNames) {
if (uniqueNames.isEmpty()) {
return;
}
switch (status) {
case Status.STATUS_COMMITTING: {
synchronized (danglingRecords) {
Set<String> outstanding = danglingRecords.get(gtrid);
if (outstanding == null) {
outstanding = new TreeSet<String>(uniqueNames);
danglingRecords.put(gtrid, outstanding);
}
outstanding.addAll(uniqueNames);
}
break;
}
case Status.STATUS_ROLLEDBACK:
case Status.STATUS_COMMITTED:
case Status.STATUS_UNKNOWN: {
synchronized (danglingRecords) {
Set<String> outstanding = danglingRecords.get(gtrid);
if (outstanding != null && outstanding.removeAll(uniqueNames) && outstanding.isEmpty()) {
danglingRecords.remove(gtrid);
}
}
break;
}
}
}
/**
* Return a {@link TransactionLogHeader} that allows reading and controlling the log file's header.
* @throws IOException if an I/O error occurs
*/
void rewind() throws IOException {
header.rewind();
position = header.getPosition();
}
/**
* Get the log file header timestamp.
* @return the log file header timestamp
*/
long getTimestamp() {
return header.getTimestamp();
}
/**
* Set the log file header timestamp
* @param timestamp the timestamp to set in the log
* @throws IOException if an I/O error occurs
*/
void setTimestamp(long timestamp) throws IOException {
header.setTimestamp(timestamp);
}
/**
* Get STATE_HEADER.
* @return the STATE_HEADER value.
*/
public byte getState() {
return header.getState();
}
/**
* Set STATE_HEADER.
* @param state the STATE_HEADER value.
* @throws IOException if an I/O error occurs.
*/
public void setState(byte state) throws IOException {
header.setState(state);
}
/**
* Get the current file position.
* @return the file position
*/
public long getPosition() {
return position;
}
/**
* Close the appender and the underlying file.
* @throws IOException if an I/O error occurs.
*/
protected void close() throws IOException {
header.setState(TransactionLogHeader.CLEAN_LOG_STATE);
fc.force(false);
if (lock != null)
lock.release();
fc.close();
randomeAccessFile.close();
}
/**
* Creates a cursor on this journal file allowing iteration of its records.
* This opens a new read-only file descriptor independent of the write-only one
* still used for writing transaction logs.
* @return a TransactionLogCursor.
* @throws IOException if an I/O error occurs.
*/
protected TransactionLogCursor getCursor() throws IOException {
return new TransactionLogCursor(file);
}
/**
* Force flushing the logs to disk
* @throws IOException if an I/O error occurs.
*/
protected void force() throws IOException {
if (log.isDebugEnabled()) { log.debug("forcing log writing"); }
fc.force(false);
if (log.isDebugEnabled()) { log.debug("done forcing log"); }
}
public String toString() {
return "a TransactionLogAppender on " + file.getName();
}
}