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Apache Tephra Transaction System Core Module
/*
* 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 co.cask.tephra.persist;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Sets;
import org.apache.tephra.ChangeId;
import org.apache.tephra.TransactionType;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
/**
* Utilities to handle encoding and decoding of {@link TransactionEdit} entries, while maintaining compatibility
* with older versions of the serialized data. This class was included for backward compatibility reasons.
* It will be removed in future releases.
*/
@Deprecated
public class TransactionEditCodecs {
private static final TransactionEditCodec[] ALL_CODECS = {
new TransactionEditCodecV1(),
new TransactionEditCodecV2(),
new TransactionEditCodecV3(),
new TransactionEditCodecV4()
};
private static final SortedMap CODECS = new TreeMap<>();
static {
for (TransactionEditCodec codec : ALL_CODECS) {
CODECS.put(codec.getVersion(), codec);
}
}
/**
* Deserializes the encoded data from the given input stream, setting the values as fields
* on the given {@code TransactionEdit} instances. This method expects first value in the
* {code DataInput} to be a byte representing the codec version used to serialize the instance.
*
* @param dest the transaction edit to populate with the deserialized values
* @param in the input stream containing the encoded data
* @throws IOException if an error occurs while deserializing from the input stream
*/
public static void decode(TransactionEdit dest, DataInput in) throws IOException {
byte version = in.readByte();
TransactionEditCodec codec = CODECS.get(version);
if (codec == null) {
throw new IOException("TransactionEdit was serialized with an unknown codec version " + version +
". Was it written with a newer version of Tephra?");
}
codec.decode(dest, in);
}
/**
* Serializes the given {@code TransactionEdit} instance with the latest available codec.
* This will first write out the version of the codec used to serialize the instance so that
* the correct codec can be used when calling {@link #decode(TransactionEdit, DataInput)}.
*
* @param src the transaction edit to serialize
* @param out the output stream to contain the data
* @throws IOException if an error occurs while serializing to the output stream
*/
public static void encode(TransactionEdit src, DataOutput out) throws IOException {
TransactionEditCodec latestCodec = CODECS.get(CODECS.firstKey());
out.writeByte(latestCodec.getVersion());
latestCodec.encode(src, out);
}
/**
* Encodes the given transaction edit using a specific codec. Note that this is only exposed
* for use by tests.
*/
@VisibleForTesting
static void encode(TransactionEdit src, DataOutput out, TransactionEditCodec codec) throws IOException {
out.writeByte(codec.getVersion());
codec.encode(src, out);
}
/**
* Defines the interface used for encoding and decoding {@link TransactionEdit} instances to and from
* binary representations.
*/
interface TransactionEditCodec {
/**
* Reads the encoded values from the data input stream and sets the fields in the given {@code TransactionEdit}
* instance.
*
* @param dest the instance on which to set all the deserialized values
* @param in the input stream containing the serialized data
* @throws IOException if an error occurs while deserializing the data
*/
void decode(TransactionEdit dest, DataInput in) throws IOException;
/**
* Writes all the field values from the {@code TransactionEdit} instance in serialized form to the data
* output stream.
*
* @param src the instance to serialize to the stream
* @param out the output stream to contain the data
* @throws IOException if an error occurs while serializing the data
*/
void encode(TransactionEdit src, DataOutput out) throws IOException;
/**
* Returns the version number for this codec. Each codec should use a unique version number, with the newest
* codec having the lowest number.
*/
byte getVersion();
}
// package-private for unit-test access
static class TransactionEditCodecV1 implements TransactionEditCodec {
@Override
public void decode(TransactionEdit dest, DataInput in) throws IOException {
dest.setWritePointer(in.readLong());
int stateIdx = in.readInt();
try {
dest.setState(TransactionEdit.State.values()[stateIdx]);
} catch (ArrayIndexOutOfBoundsException e) {
throw new IOException("State enum ordinal value is out of range: " + stateIdx);
}
dest.setExpiration(in.readLong());
dest.setCommitPointer(in.readLong());
dest.setCanCommit(in.readBoolean());
int changeSize = in.readInt();
Set changes = Sets.newHashSet();
for (int i = 0; i < changeSize; i++) {
int currentLength = in.readInt();
byte[] currentBytes = new byte[currentLength];
in.readFully(currentBytes);
changes.add(new ChangeId(currentBytes));
}
dest.setChanges(changes);
// 1st version did not store this info. It is safe to set firstInProgress to 0, it may decrease performance until
// this tx is finished, but correctness will be preserved.
dest.setVisibilityUpperBound(0);
}
/** @deprecated use {@link TransactionEditCodecs.TransactionEditCodecV4} instead, it is still here for
* unit-tests only */
@Override
@Deprecated
public void encode(TransactionEdit src, DataOutput out) throws IOException {
out.writeLong(src.getWritePointer());
// use ordinal for predictable size, though this does not support evolution
out.writeInt(src.getState().ordinal());
out.writeLong(src.getExpiration());
out.writeLong(src.getCommitPointer());
out.writeBoolean(src.getCanCommit());
Set changes = src.getChanges();
if (changes == null) {
out.writeInt(0);
} else {
out.writeInt(changes.size());
for (ChangeId c : changes) {
byte[] cKey = c.getKey();
out.writeInt(cKey.length);
out.write(cKey);
}
}
// NOTE: we didn't have visibilityUpperBound in V1, it was added in V2
// we didn't have transaction type, truncateInvalidTx and truncateInvalidTxTime in V1 and V2,
// it was added in V3
}
@Override
public byte getVersion() {
return -1;
}
}
// package-private for unit-test access
static class TransactionEditCodecV2 extends TransactionEditCodecV1 implements TransactionEditCodec {
@Override
public void decode(TransactionEdit dest, DataInput in) throws IOException {
super.decode(dest, in);
dest.setVisibilityUpperBound(in.readLong());
}
/** @deprecated use {@link TransactionEditCodecs.TransactionEditCodecV4} instead, it is still here for
* unit-tests only */
@Override
public void encode(TransactionEdit src, DataOutput out) throws IOException {
super.encode(src, out);
out.writeLong(src.getVisibilityUpperBound());
// NOTE: we didn't have transaction type, truncateInvalidTx and truncateInvalidTxTime in V1 and V2,
// it was added in V3
}
@Override
public byte getVersion() {
return -2;
}
}
// TODO: refactor to avoid duplicate code among different version of codecs
// package-private for unit-test access
static class TransactionEditCodecV3 extends TransactionEditCodecV2 implements TransactionEditCodec {
@Override
public void decode(TransactionEdit dest, DataInput in) throws IOException {
super.decode(dest, in);
int typeIdx = in.readInt();
// null transaction type is represented as -1
if (typeIdx < 0) {
dest.setType(null);
} else {
try {
dest.setType(TransactionType.values()[typeIdx]);
} catch (ArrayIndexOutOfBoundsException e) {
throw new IOException("Type enum ordinal value is out of range: " + typeIdx);
}
}
int truncateInvalidTxSize = in.readInt();
Set truncateInvalidTx = emptySet(dest.getTruncateInvalidTx());
for (int i = 0; i < truncateInvalidTxSize; i++) {
truncateInvalidTx.add(in.readLong());
}
dest.setTruncateInvalidTx(truncateInvalidTx);
dest.setTruncateInvalidTxTime(in.readLong());
}
private Set emptySet(Set set) {
if (set == null) {
return Sets.newHashSet();
}
set.clear();
return set;
}
@Override
public void encode(TransactionEdit src, DataOutput out) throws IOException {
super.encode(src, out);
// null transaction type is represented as -1
if (src.getType() == null) {
out.writeInt(-1);
} else {
out.writeInt(src.getType().ordinal());
}
Set truncateInvalidTx = src.getTruncateInvalidTx();
if (truncateInvalidTx == null) {
out.writeInt(0);
} else {
out.writeInt(truncateInvalidTx.size());
for (long id : truncateInvalidTx) {
out.writeLong(id);
}
}
out.writeLong(src.getTruncateInvalidTxTime());
}
@Override
public byte getVersion() {
return -3;
}
}
static class TransactionEditCodecV4 extends TransactionEditCodecV3 {
@Override
public void decode(TransactionEdit dest, DataInput in) throws IOException {
super.decode(dest, in);
dest.setParentWritePointer(in.readLong());
int checkpointPointersLen = in.readInt();
if (checkpointPointersLen >= 0) {
long[] checkpointPointers = new long[checkpointPointersLen];
for (int i = 0; i < checkpointPointersLen; i++) {
checkpointPointers[i] = in.readLong();
}
dest.setCheckpointPointers(checkpointPointers);
}
}
@Override
public void encode(TransactionEdit src, DataOutput out) throws IOException {
super.encode(src, out);
out.writeLong(src.getParentWritePointer());
long[] checkpointPointers = src.getCheckpointPointers();
if (checkpointPointers == null) {
out.writeInt(-1);
} else {
out.writeInt(checkpointPointers.length);
for (int i = 0; i < checkpointPointers.length; i++) {
out.writeLong(checkpointPointers[i]);
}
}
}
@Override
public byte getVersion() {
return -4;
}
}
}
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