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Elasticsearch subproject :server
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.index.translog;
import org.elasticsearch.common.io.Channels;
import org.elasticsearch.index.seqno.SequenceNumbers;
import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
final class TranslogSnapshot extends BaseTranslogReader {
private final int totalOperations;
private final Checkpoint checkpoint;
protected final long length;
private final ByteBuffer reusableBuffer;
private long position;
private int skippedOperations;
private int readOperations;
private BufferedChecksumStreamInput reuse;
/**
* Create a snapshot of translog file channel.
*/
TranslogSnapshot(final BaseTranslogReader reader, final long length) {
super(reader.generation, reader.channel, reader.path, reader.header);
this.length = length;
this.totalOperations = reader.totalOperations();
this.checkpoint = reader.getCheckpoint();
this.reusableBuffer = ByteBuffer.allocate(1024);
this.readOperations = 0;
this.position = reader.getFirstOperationOffset();
this.reuse = null;
}
@Override
public int totalOperations() {
return totalOperations;
}
int skippedOperations() {
return skippedOperations;
}
@Override
Checkpoint getCheckpoint() {
return checkpoint;
}
public Translog.Operation next() throws IOException {
while (readOperations < totalOperations) {
final Translog.Operation operation = readOperation();
if (operation.seqNo() <= checkpoint.trimmedAboveSeqNo || checkpoint.trimmedAboveSeqNo == SequenceNumbers.UNASSIGNED_SEQ_NO) {
return operation;
}
skippedOperations++;
}
return null;
}
private Translog.Operation readOperation() throws IOException {
final int opSize = readSize(reusableBuffer, position);
reuse = checksummedStream(reusableBuffer, position, opSize, reuse);
Translog.Operation op = read(reuse);
position += opSize;
readOperations++;
return op;
}
public long sizeInBytes() {
return length;
}
/**
* reads an operation at the given position into the given buffer.
*/
protected void readBytes(ByteBuffer buffer, long position) throws IOException {
try {
if (position >= length) {
throw new EOFException(
"read requested past EOF. pos ["
+ position
+ "] end: ["
+ length
+ "], generation: ["
+ getGeneration()
+ "], path: ["
+ path
+ "]"
);
}
if (position < getFirstOperationOffset()) {
throw new IOException(
"read requested before position of first ops. pos ["
+ position
+ "] first op on: ["
+ getFirstOperationOffset()
+ "], generation: ["
+ getGeneration()
+ "], path: ["
+ path
+ "]"
);
}
Channels.readFromFileChannelWithEofException(channel, position, buffer);
} catch (EOFException e) {
throw new TranslogCorruptedException(path.toString(), "translog truncated", e);
}
}
@Override
public String toString() {
return "TranslogSnapshot{"
+ "readOperations="
+ readOperations
+ ", position="
+ position
+ ", estimateTotalOperations="
+ totalOperations
+ ", length="
+ length
+ ", generation="
+ generation
+ ", reusableBuffer="
+ reusableBuffer
+ '}';
}
}