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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.index.translog;
import org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.store.InputStreamDataInput;
import org.apache.lucene.store.OutputStreamDataOutput;
import org.apache.lucene.util.IOUtils;
import org.elasticsearch.common.io.stream.*;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
/**
* Version 1 of the translog file format. Writes a header to identify the
* format, also writes checksums for each operation
*/
public class ChecksummedTranslogStream implements TranslogStream {
public static final int VERSION = 1;
ChecksummedTranslogStream() {
}
private void verifyChecksum(BufferedChecksumStreamInput in) throws IOException {
// This absolutely must come first, or else reading the checksum becomes part of the checksum
long expectedChecksum = in.getChecksum();
long readChecksum = in.readInt() & 0xFFFF_FFFFL;
if (readChecksum != expectedChecksum) {
throw new TranslogCorruptedException("translog stream is corrupted, expected: 0x" +
Long.toHexString(expectedChecksum) + ", got: 0x" + Long.toHexString(readChecksum));
}
}
@Override
public Translog.Operation read(StreamInput inStream) throws IOException {
// TODO: validate size to prevent OOME
int opSize = inStream.readInt();
// This BufferedChecksumStreamInput remains unclosed on purpose,
// because closing it closes the underlying stream, which we don't
// want to do here.
BufferedChecksumStreamInput in = new BufferedChecksumStreamInput(inStream);
Translog.Operation operation;
try {
Translog.Operation.Type type = Translog.Operation.Type.fromId(in.readByte());
operation = TranslogStreams.newOperationFromType(type);
operation.readFrom(in);
} catch (AssertionError|Exception e) {
throw new TranslogCorruptedException("translog corruption while reading from stream", e);
}
verifyChecksum(in);
return operation;
}
@Override
public void write(StreamOutput outStream, Translog.Operation op) throws IOException {
// We first write to a NoopStreamOutput to get the size of the
// operation. We could write to a byte array and then send that as an
// alternative, but here we choose to use CPU over allocating new
// byte arrays.
NoopStreamOutput noopOut = new NoopStreamOutput();
noopOut.writeByte(op.opType().id());
op.writeTo(noopOut);
noopOut.writeInt(0); // checksum holder
int size = noopOut.getCount();
// This BufferedChecksumStreamOutput remains unclosed on purpose,
// because closing it closes the underlying stream, which we don't
// want to do here.
BufferedChecksumStreamOutput out = new BufferedChecksumStreamOutput(outStream);
outStream.writeInt(size); // opSize is not checksummed
out.writeByte(op.opType().id());
op.writeTo(out);
long checksum = out.getChecksum();
out.writeInt((int)checksum);
}
@Override
public int writeHeader(FileChannel channel) throws IOException {
// This OutputStreamDataOutput is intentionally not closed because
// closing it will close the FileChannel
OutputStreamDataOutput out = new OutputStreamDataOutput(Channels.newOutputStream(channel));
CodecUtil.writeHeader(out, TranslogStreams.TRANSLOG_CODEC, VERSION);
return CodecUtil.headerLength(TranslogStreams.TRANSLOG_CODEC);
}
@Override
public StreamInput openInput(File translogFile) throws IOException {
final FileInputStream fileInputStream = new FileInputStream(translogFile);
boolean success = false;
try {
final InputStreamStreamInput in = new InputStreamStreamInput(fileInputStream);
CodecUtil.checkHeader(new InputStreamDataInput(in), TranslogStreams.TRANSLOG_CODEC, VERSION, VERSION);
success = true;
return in;
} catch (EOFException e) {
throw new TruncatedTranslogException("translog header truncated", e);
} catch (IOException e) {
throw new TranslogCorruptedException("translog header corrupted", e);
} finally {
if (success == false) {
IOUtils.closeWhileHandlingException(fileInputStream);
}
}
}
}