/*
* 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.cassandra.streaming.compress;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.cassandra.io.compress.CompressionMetadata;
import org.apache.cassandra.io.sstable.SSTableReader;
import org.apache.cassandra.io.util.FileUtils;
import org.apache.cassandra.io.util.RandomAccessReader;
import org.apache.cassandra.streaming.ProgressInfo;
import org.apache.cassandra.streaming.StreamSession;
import org.apache.cassandra.streaming.StreamWriter;
import org.apache.cassandra.utils.Pair;
/**
* StreamWriter for compressed SSTable.
*/
public class CompressedStreamWriter extends StreamWriter
{
public static final int CHUNK_SIZE = 10 * 1024 * 1024;
private final CompressionInfo compressionInfo;
public CompressedStreamWriter(SSTableReader sstable, Collection<Pair<Long, Long>> sections, CompressionInfo compressionInfo, StreamSession session)
{
super(sstable, sections, session);
this.compressionInfo = compressionInfo;
}
@Override
public void write(WritableByteChannel channel) throws IOException
{
long totalSize = totalSize();
RandomAccessReader file = sstable.openDataReader();
FileChannel fc = file.getChannel();
long progress = 0L;
// calculate chunks to transfer. we want to send continuous chunks altogether.
List<Pair<Long, Long>> sections = getTransferSections(compressionInfo.chunks);
try
{
// stream each of the required sections of the file
for (Pair<Long, Long> section : sections)
{
// length of the section to stream
long length = section.right - section.left;
// tracks write progress
long bytesTransferred = 0;
while (bytesTransferred < length)
{
int toTransfer = (int) Math.min(CHUNK_SIZE, length - bytesTransferred);
limiter.acquire(toTransfer);
long lastWrite = fc.transferTo(section.left + bytesTransferred, toTransfer, channel);
bytesTransferred += lastWrite;
progress += lastWrite;
session.progress(sstable.descriptor, ProgressInfo.Direction.OUT, progress, totalSize);
}
}
}
finally
{
// no matter what happens close file
FileUtils.closeQuietly(file);
}
}
@Override
protected long totalSize()
{
long size = 0;
// calculate total length of transferring chunks
for (CompressionMetadata.Chunk chunk : compressionInfo.chunks)
size += chunk.length + 4; // 4 bytes for CRC
return size;
}
// chunks are assumed to be sorted by offset
private List<Pair<Long, Long>> getTransferSections(CompressionMetadata.Chunk[] chunks)
{
List<Pair<Long, Long>> transferSections = new ArrayList<>();
Pair<Long, Long> lastSection = null;
for (CompressionMetadata.Chunk chunk : chunks)
{
if (lastSection != null)
{
if (chunk.offset == lastSection.right)
{
// extend previous section to end of this chunk
lastSection = Pair.create(lastSection.left, chunk.offset + chunk.length + 4); // 4 bytes for CRC
}
else
{
transferSections.add(lastSection);
lastSection = Pair.create(chunk.offset, chunk.offset + chunk.length + 4);
}
}
else
{
lastSection = Pair.create(chunk.offset, chunk.offset + chunk.length + 4);
}
}
if (lastSection != null)
transferSections.add(lastSection);
return transferSections;
}
}