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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.db.streaming;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import org.apache.cassandra.db.TypeSizes;
import org.apache.cassandra.io.IVersionedSerializer;
import org.apache.cassandra.io.compress.CompressionMetadata;
import org.apache.cassandra.io.compress.CompressionMetadata.Chunk;
import org.apache.cassandra.io.sstable.format.SSTableReader;
import org.apache.cassandra.schema.CompressionParams;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
/**
* Container that carries compression parameters and chunks to decompress data from stream.
*/
public abstract class CompressionInfo
{
public static final IVersionedSerializer serializer = new CompressionInfoSerializer();
/**
* Returns the compression parameters.
*
* @return the compression parameters.
*/
public abstract CompressionParams parameters();
/**
* Returns the offset and length of the file chunks.
*
* @return the offset and length of the file chunks.
*/
public abstract CompressionMetadata.Chunk[] chunks();
/**
* Computes the size of the file to transfer.
*
* @return the size of the file in bytes
*/
public long getTotalSize()
{
long size = 0;
for (CompressionMetadata.Chunk chunk : chunks())
{
size += chunk.length + 4; // 4 bytes for CRC
}
return size;
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
if (!(o instanceof CompressionInfo))
return false;
CompressionInfo that = (CompressionInfo) o;
return Objects.equals(parameters(), that.parameters())
&& Arrays.equals(chunks(), that.chunks());
}
@Override
public int hashCode()
{
return Objects.hash(parameters(), chunks());
}
/**
* Create a {@code CompressionInfo} instance which is fully initialized.
*
* @param chunks the file chunks
* @param parameters the compression parameters
*/
public static CompressionInfo newInstance(CompressionMetadata.Chunk[] chunks, CompressionParams parameters)
{
assert chunks != null && parameters != null;
return new CompressionInfo()
{
@Override
public Chunk[] chunks()
{
return chunks;
}
@Override
public CompressionParams parameters()
{
return parameters;
}
};
}
/**
* Create a {@code CompressionInfo} that will computes the file chunks only upon request.
*
* The instance returned by that method will only computes the file chunks when the {@code chunks},
* {@code equals} or {@code hashcode} methods are called for the first time. This is done to reduce the GC
* pressure. See CASSANDRA-10680 for more details
.
*
* @param metadata the compression metadata
* @param sections the file sections
* @return a {@code CompressionInfo} that will computes the file chunks only upon request.
*/
static CompressionInfo newLazyInstance(CompressionMetadata metadata, List sections)
{
if (metadata == null)
{
return null;
}
return new CompressionInfo()
{
private volatile Chunk[] chunks;
@Override
public synchronized Chunk[] chunks()
{
if (chunks == null)
chunks = metadata.getChunksForSections(sections);
return chunks;
}
@Override
public CompressionParams parameters()
{
return metadata.parameters;
}
@Override
public long getTotalSize()
{
// If the chunks have not been loaded yet we avoid to compute them.
if (chunks == null)
return metadata.getTotalSizeForSections(sections);
return super.getTotalSize();
}
};
}
static class CompressionInfoSerializer implements IVersionedSerializer
{
public void serialize(CompressionInfo info, DataOutputPlus out, int version) throws IOException
{
if (info == null)
{
out.writeInt(-1);
return;
}
Chunk[] chunks = info.chunks();
int chunkCount = chunks.length;
out.writeInt(chunkCount);
for (int i = 0; i < chunkCount; i++)
CompressionMetadata.Chunk.serializer.serialize(chunks[i], out, version);
// compression params
CompressionParams.serializer.serialize(info.parameters(), out, version);
}
public CompressionInfo deserialize(DataInputPlus in, int version) throws IOException
{
// chunks
int chunkCount = in.readInt();
if (chunkCount < 0)
return null;
CompressionMetadata.Chunk[] chunks = new CompressionMetadata.Chunk[chunkCount];
for (int i = 0; i < chunkCount; i++)
chunks[i] = CompressionMetadata.Chunk.serializer.deserialize(in, version);
// compression params
CompressionParams parameters = CompressionParams.serializer.deserialize(in, version);
return CompressionInfo.newInstance(chunks, parameters);
}
public long serializedSize(CompressionInfo info, int version)
{
if (info == null)
return TypeSizes.sizeof(-1);
// chunks
Chunk[] chunks = info.chunks();
int chunkCount = chunks.length;
long size = TypeSizes.sizeof(chunkCount);
for (int i = 0; i < chunkCount; i++)
size += CompressionMetadata.Chunk.serializer.serializedSize(chunks[i], version);
// compression params
size += CompressionParams.serializer.serializedSize(info.parameters(), version);
return size;
}
}
}