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* 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 com.datastax.oss.driver.internal.core.protocol;
import com.datastax.oss.driver.api.core.context.DriverContext;
import com.datastax.oss.driver.internal.core.util.DefaultDependencyChecker;
import com.datastax.oss.driver.internal.core.util.Dependency;
import com.datastax.oss.driver.shaded.netty.buffer.ByteBuf;
import java.io.IOException;
import java.nio.ByteBuffer;
import net.jcip.annotations.ThreadSafe;
import org.xerial.snappy.Snappy;
/**
* @implNote The Snappy protocol already encodes the uncompressed length in the compressed payload,
* so {@link #compress(ByteBuf)} and {@link #compressWithoutLength(ByteBuf)} produce the same
* output for this compressor. The corresponding parameters {@code
* prependWithUncompressedLength} and {@code uncompressedLength} are ignored by their respective
* methods.
*/
@ThreadSafe
public class SnappyCompressor extends ByteBufCompressor {
public SnappyCompressor(@SuppressWarnings("unused") DriverContext context) {
if (!DefaultDependencyChecker.isPresent(Dependency.SNAPPY)) {
throw new IllegalStateException(
"Could not find the Snappy library on the classpath "
+ "(the driver declares it as an optional dependency, "
+ "so you need to declare it explicitly)");
}
}
@Override
public String algorithm() {
return "snappy";
}
@Override
protected ByteBuf compressDirect(
ByteBuf input, /*ignored*/ boolean prependWithUncompressedLength) {
int maxCompressedLength = Snappy.maxCompressedLength(input.readableBytes());
// If the input is direct we will allocate a direct output buffer as well as this will allow us
// to use Snappy.compress(ByteBuffer, ByteBuffer) and so eliminate memory copies.
ByteBuf output = input.alloc().directBuffer(maxCompressedLength);
try {
ByteBuffer in = inputNioBuffer(input);
// Increase reader index.
input.readerIndex(input.writerIndex());
ByteBuffer out = outputNioBuffer(output);
int written = Snappy.compress(in, out);
// Set the writer index so the amount of written bytes is reflected
output.writerIndex(output.writerIndex() + written);
return output;
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw new RuntimeException(e);
}
}
@Override
protected ByteBuf compressHeap(ByteBuf input, /*ignored*/ boolean prependWithUncompressedLength) {
int maxCompressedLength = Snappy.maxCompressedLength(input.readableBytes());
int inOffset = input.arrayOffset() + input.readerIndex();
byte[] in = input.array();
int len = input.readableBytes();
// Increase reader index.
input.readerIndex(input.writerIndex());
// Allocate a heap buffer from the ByteBufAllocator as we may use a PooledByteBufAllocator and
// so can eliminate the overhead of allocate a new byte[].
ByteBuf output = input.alloc().heapBuffer(maxCompressedLength);
try {
// Calculate the correct offset.
int offset = output.arrayOffset() + output.writerIndex();
byte[] out = output.array();
int written = Snappy.compress(in, inOffset, len, out, offset);
// Increase the writerIndex with the written bytes.
output.writerIndex(output.writerIndex() + written);
return output;
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw new RuntimeException(e);
}
}
@Override
protected int readUncompressedLength(ByteBuf compressed) {
// Since compress methods don't actually prepend with a length, we have nothing to read here.
// Return a bogus length (it will be ignored by the decompress methods, so the actual value
// doesn't matter).
return -1;
}
@Override
protected ByteBuf decompressDirect(ByteBuf input, /*ignored*/ int uncompressedLength) {
ByteBuffer in = inputNioBuffer(input);
// Increase reader index.
input.readerIndex(input.writerIndex());
ByteBuf output = null;
try {
if (!Snappy.isValidCompressedBuffer(in)) {
throw new IllegalArgumentException(
"Provided frame does not appear to be Snappy compressed");
}
// If the input is direct we will allocate a direct output buffer as well as this will allow
// us to use Snappy.compress(ByteBuffer, ByteBuffer) and so eliminate memory copies.
output = input.alloc().directBuffer(Snappy.uncompressedLength(in));
ByteBuffer out = outputNioBuffer(output);
int size = Snappy.uncompress(in, out);
// Set the writer index so the amount of written bytes is reflected
output.writerIndex(output.writerIndex() + size);
return output;
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
if (output != null) {
output.release();
}
throw new RuntimeException(e);
}
}
@Override
protected ByteBuf decompressHeap(ByteBuf input, /*ignored*/ int uncompressedLength) {
// Not a direct buffer so use byte arrays...
int inOffset = input.arrayOffset() + input.readerIndex();
byte[] in = input.array();
int len = input.readableBytes();
// Increase reader index.
input.readerIndex(input.writerIndex());
ByteBuf output = null;
try {
if (!Snappy.isValidCompressedBuffer(in, inOffset, len)) {
throw new IllegalArgumentException(
"Provided frame does not appear to be Snappy compressed");
}
// Allocate a heap buffer from the ByteBufAllocator as we may use a PooledByteBufAllocator and
// so can eliminate the overhead of allocate a new byte[].
output = input.alloc().heapBuffer(Snappy.uncompressedLength(in, inOffset, len));
// Calculate the correct offset.
int offset = output.arrayOffset() + output.writerIndex();
byte[] out = output.array();
int written = Snappy.uncompress(in, inOffset, len, out, offset);
// Increase the writerIndex with the written bytes.
output.writerIndex(output.writerIndex() + written);
return output;
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
if (output != null) {
output.release();
}
throw new RuntimeException(e);
}
}
}