326 lines
11 KiB
Java
326 lines
11 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.compression;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelFuture;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelPromise;
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import io.netty.channel.ChannelPromiseNotifier;
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import io.netty.util.concurrent.EventExecutor;
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import java.util.concurrent.TimeUnit;
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import java.util.zip.CRC32;
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import java.util.zip.Deflater;
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/**
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* Compresses a {@link ByteBuf} using the deflate algorithm.
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*/
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public class JdkZlibEncoder extends ZlibEncoder {
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private final ZlibWrapper wrapper;
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private final Deflater deflater;
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private volatile boolean finished;
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private volatile ChannelHandlerContext ctx;
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/*
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* GZIP support
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*/
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private final CRC32 crc = new CRC32();
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private static final byte[] gzipHeader = {0x1f, (byte) 0x8b, Deflater.DEFLATED, 0, 0, 0, 0, 0, 0, 0};
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private boolean writeHeader = true;
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/**
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* Creates a new zlib encoder with the default compression level ({@code 6})
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* and the default wrapper ({@link ZlibWrapper#ZLIB}).
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*
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* @throws CompressionException if failed to initialize zlib
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*/
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public JdkZlibEncoder() {
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this(6);
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}
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/**
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* Creates a new zlib encoder with the specified {@code compressionLevel}
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* and the default wrapper ({@link ZlibWrapper#ZLIB}).
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*
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* @param compressionLevel
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* {@code 1} yields the fastest compression and {@code 9} yields the
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* best compression. {@code 0} means no compression. The default
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* compression level is {@code 6}.
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*
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* @throws CompressionException if failed to initialize zlib
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*/
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public JdkZlibEncoder(int compressionLevel) {
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this(ZlibWrapper.ZLIB, compressionLevel);
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}
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/**
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* Creates a new zlib encoder with the default compression level ({@code 6})
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* and the specified wrapper.
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*
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* @throws CompressionException if failed to initialize zlib
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*/
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public JdkZlibEncoder(ZlibWrapper wrapper) {
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this(wrapper, 6);
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}
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/**
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* Creates a new zlib encoder with the specified {@code compressionLevel}
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* and the specified wrapper.
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*
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* @param compressionLevel
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* {@code 1} yields the fastest compression and {@code 9} yields the
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* best compression. {@code 0} means no compression. The default
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* compression level is {@code 6}.
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*
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* @throws CompressionException if failed to initialize zlib
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*/
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public JdkZlibEncoder(ZlibWrapper wrapper, int compressionLevel) {
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if (compressionLevel < 0 || compressionLevel > 9) {
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throw new IllegalArgumentException(
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"compressionLevel: " + compressionLevel + " (expected: 0-9)");
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}
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if (wrapper == null) {
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throw new NullPointerException("wrapper");
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}
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if (wrapper == ZlibWrapper.ZLIB_OR_NONE) {
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throw new IllegalArgumentException(
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"wrapper '" + ZlibWrapper.ZLIB_OR_NONE + "' is not " +
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"allowed for compression.");
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}
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this.wrapper = wrapper;
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deflater = new Deflater(compressionLevel, wrapper != ZlibWrapper.ZLIB);
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}
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/**
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* Creates a new zlib encoder with the default compression level ({@code 6})
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* and the specified preset dictionary. The wrapper is always
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* {@link ZlibWrapper#ZLIB} because it is the only format that supports
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* the preset dictionary.
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*
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* @param dictionary the preset dictionary
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*
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* @throws CompressionException if failed to initialize zlib
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*/
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public JdkZlibEncoder(byte[] dictionary) {
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this(6, dictionary);
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}
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/**
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* Creates a new zlib encoder with the specified {@code compressionLevel}
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* and the specified preset dictionary. The wrapper is always
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* {@link ZlibWrapper#ZLIB} because it is the only format that supports
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* the preset dictionary.
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*
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* @param compressionLevel
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* {@code 1} yields the fastest compression and {@code 9} yields the
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* best compression. {@code 0} means no compression. The default
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* compression level is {@code 6}.
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* @param dictionary the preset dictionary
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*
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* @throws CompressionException if failed to initialize zlib
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*/
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public JdkZlibEncoder(int compressionLevel, byte[] dictionary) {
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if (compressionLevel < 0 || compressionLevel > 9) {
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throw new IllegalArgumentException(
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"compressionLevel: " + compressionLevel + " (expected: 0-9)");
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}
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if (dictionary == null) {
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throw new NullPointerException("dictionary");
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}
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wrapper = ZlibWrapper.ZLIB;
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deflater = new Deflater(compressionLevel);
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deflater.setDictionary(dictionary);
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}
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@Override
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public ChannelFuture close() {
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return close(ctx().newPromise());
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}
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@Override
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public ChannelFuture close(final ChannelPromise promise) {
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ChannelHandlerContext ctx = ctx();
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EventExecutor executor = ctx.executor();
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if (executor.inEventLoop()) {
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return finishEncode(ctx, promise);
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} else {
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final ChannelPromise p = ctx.newPromise();
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executor.execute(new Runnable() {
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@Override
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public void run() {
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ChannelFuture f = finishEncode(ctx(), p);
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f.addListener(new ChannelPromiseNotifier(promise));
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}
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});
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return p;
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}
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}
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private ChannelHandlerContext ctx() {
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ChannelHandlerContext ctx = this.ctx;
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if (ctx == null) {
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throw new IllegalStateException("not added to a pipeline");
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}
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return ctx;
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}
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@Override
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public boolean isClosed() {
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return finished;
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}
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@Override
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protected void encode(ChannelHandlerContext ctx, ByteBuf uncompressed, ByteBuf out) throws Exception {
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if (finished) {
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out.writeBytes(uncompressed);
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return;
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}
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int len = uncompressed.readableBytes();
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if (len == 0) {
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return;
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}
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int offset;
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byte[] inAry;
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if (uncompressed.hasArray()) {
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// if it is backed by an array we not need to to do a copy at all
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inAry = uncompressed.array();
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offset = uncompressed.arrayOffset() + uncompressed.readerIndex();
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// skip all bytes as we will consume all of them
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uncompressed.skipBytes(len);
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} else {
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inAry = new byte[len];
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uncompressed.readBytes(inAry);
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offset = 0;
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}
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if (writeHeader) {
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writeHeader = false;
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if (wrapper == ZlibWrapper.GZIP) {
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out.writeBytes(gzipHeader);
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}
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}
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if (wrapper == ZlibWrapper.GZIP) {
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crc.update(inAry, offset, len);
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}
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deflater.setInput(inAry, offset, len);
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while (!deflater.needsInput()) {
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deflate(out);
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}
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}
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@Override
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protected final ByteBuf allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg,
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boolean preferDirect) throws Exception {
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int sizeEstimate = (int) Math.ceil(msg.readableBytes() * 1.001) + 12;
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if (writeHeader) {
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switch (wrapper) {
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case GZIP:
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sizeEstimate += gzipHeader.length;
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break;
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case ZLIB:
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sizeEstimate += 2; // first two magic bytes
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break;
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}
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}
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return ctx.alloc().heapBuffer(sizeEstimate);
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}
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@Override
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public void close(final ChannelHandlerContext ctx, final ChannelPromise promise) throws Exception {
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ChannelFuture f = finishEncode(ctx, ctx.newPromise());
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f.addListener(new ChannelFutureListener() {
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@Override
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public void operationComplete(ChannelFuture f) throws Exception {
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ctx.close(promise);
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}
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});
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if (!f.isDone()) {
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// Ensure the channel is closed even if the write operation completes in time.
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ctx.executor().schedule(new Runnable() {
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@Override
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public void run() {
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ctx.close(promise);
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}
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}, 10, TimeUnit.SECONDS); // FIXME: Magic number
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}
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}
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private ChannelFuture finishEncode(final ChannelHandlerContext ctx, ChannelPromise promise) {
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if (finished) {
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promise.setSuccess();
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return promise;
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}
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finished = true;
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ByteBuf footer = ctx.alloc().heapBuffer();
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if (writeHeader && wrapper == ZlibWrapper.GZIP) {
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// Write the GZIP header first if not written yet. (i.e. user wrote nothing.)
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writeHeader = false;
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footer.writeBytes(gzipHeader);
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}
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deflater.finish();
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while (!deflater.finished()) {
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deflate(footer);
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if (!footer.isWritable()) {
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// no more space so write it to the channel and continue
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ctx.write(footer);
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footer = ctx.alloc().heapBuffer();
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}
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}
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if (wrapper == ZlibWrapper.GZIP) {
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int crcValue = (int) crc.getValue();
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int uncBytes = deflater.getTotalIn();
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footer.writeByte(crcValue);
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footer.writeByte(crcValue >>> 8);
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footer.writeByte(crcValue >>> 16);
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footer.writeByte(crcValue >>> 24);
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footer.writeByte(uncBytes);
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footer.writeByte(uncBytes >>> 8);
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footer.writeByte(uncBytes >>> 16);
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footer.writeByte(uncBytes >>> 24);
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}
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deflater.end();
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return ctx.writeAndFlush(footer, promise);
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}
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private void deflate(ByteBuf out) {
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int numBytes;
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do {
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int writerIndex = out.writerIndex();
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numBytes = deflater.deflate(
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out.array(), out.arrayOffset() + writerIndex, out.writableBytes(), Deflater.SYNC_FLUSH);
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out.writerIndex(writerIndex + numBytes);
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} while (numBytes > 0);
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}
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@Override
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public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
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this.ctx = ctx;
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}
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}
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