/*
* Copyright (C) 2012-2015 DataStax Inc.
*
* Licensed 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.driver.core;
import com.datastax.driver.core.exceptions.DriverInternalError;
import io.netty.buffer.ByteBuf;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xerial.snappy.Snappy;
import java.io.IOException;
import java.nio.ByteBuffer;
class SnappyCompressor extends FrameCompressor {
private static final Logger logger = LoggerFactory.getLogger(SnappyCompressor.class);
static final SnappyCompressor instance;
static {
SnappyCompressor i;
try {
i = new SnappyCompressor();
} catch (NoClassDefFoundError e) {
i = null;
logger.warn("Cannot find Snappy class, you should make sure the Snappy library is in the classpath if you intend to use it. Snappy compression will not be available for the protocol.");
} catch (Throwable e) {
i = null;
logger.warn("Error loading Snappy library ({}). Snappy compression will not be available for the protocol.", e.toString());
}
instance = i;
}
private SnappyCompressor() {
// this would throw java.lang.NoClassDefFoundError if Snappy class
// wasn't found at runtime which should be processed by the calling method
Snappy.getNativeLibraryVersion();
}
@Override
Frame compress(Frame frame) throws IOException {
ByteBuf input = frame.body;
ByteBuf frameBody = input.isDirect() ? compressDirect(input) : compressHeap(input);
return frame.with(frameBody);
}
private ByteBuf compressDirect(ByteBuf input) throws IOException {
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);
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw e;
}
return output;
}
private ByteBuf compressHeap(ByteBuf input) throws IOException {
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);
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw e;
}
return output;
}
@Override
Frame decompress(Frame frame) throws IOException {
ByteBuf input = frame.body;
ByteBuf frameBody = input.isDirect() ? decompressDirect(input) : decompressHeap(input);
return frame.with(frameBody);
}
private ByteBuf decompressDirect(ByteBuf input) throws IOException {
ByteBuffer in = inputNioBuffer(input);
// Increase reader index.
input.readerIndex(input.writerIndex());
if (!Snappy.isValidCompressedBuffer(in))
throw new DriverInternalError("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.
ByteBuf output = input.alloc().directBuffer(Snappy.uncompressedLength(in));
try {
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);
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw e;
}
return output;
}
private ByteBuf decompressHeap(ByteBuf input) throws IOException {
// 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());
if (!Snappy.isValidCompressedBuffer(in, inOffset, len))
throw new DriverInternalError("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[].
ByteBuf output = input.alloc().heapBuffer(Snappy.uncompressedLength(in, inOffset, len));
try {
// 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);
} catch (IOException e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw e;
}
return output;
}
}