/*
* Copyright 2011 The Netty Project
*
* The Netty Project 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.jboss.netty.handler.codec.compression;
import java.util.concurrent.atomic.AtomicBoolean;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelFutureListener;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.LifeCycleAwareChannelHandler;
import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
import org.jboss.netty.util.internal.jzlib.JZlib;
import org.jboss.netty.util.internal.jzlib.ZStream;
/**
* Compresses a {@link ChannelBuffer} using the deflate algorithm.
* @apiviz.landmark
* @apiviz.has org.jboss.netty.handler.codec.compression.ZlibWrapper
*/
public class ZlibEncoder extends OneToOneEncoder implements LifeCycleAwareChannelHandler {
private static final byte[] EMPTY_ARRAY = new byte[0];
private final ZStream z = new ZStream();
private final AtomicBoolean finished = new AtomicBoolean();
private volatile ChannelHandlerContext ctx;
/**
* Creates a new zlib encoder with the default compression level ({@code 6}),
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the default wrapper ({@link ZlibWrapper#ZLIB}).
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder() {
this(6);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the default wrapper ({@link ZlibWrapper#ZLIB}).
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(int compressionLevel) {
this(ZlibWrapper.ZLIB, compressionLevel);
}
/**
* Creates a new zlib encoder with the default compression level ({@code 6}),
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified wrapper.
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(ZlibWrapper wrapper) {
this(wrapper, 6);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified wrapper.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(ZlibWrapper wrapper, int compressionLevel) {
this(wrapper, compressionLevel, 15, 8);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* the specified {@code windowBits}, the specified {@code memLevel}, and
* the specified wrapper.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
* @param windowBits
* The base two logarithm of the size of the history buffer. The
* value should be in the range {@code 9} to {@code 15} inclusive.
* Larger values result in better compression at the expense of
* memory usage. The default value is {@code 15}.
* @param memLevel
* How much memory should be allocated for the internal compression
* state. {@code 1} uses minimum memory and {@code 9} uses maximum
* memory. Larger values result in better and faster compression
* at the expense of memory usage. The default value is {@code 8}
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(ZlibWrapper wrapper, int compressionLevel, int windowBits, int memLevel) {
if (compressionLevel < 0 || compressionLevel > 9) {
throw new IllegalArgumentException(
"compressionLevel: " + compressionLevel + " (expected: 0-9)");
}
if (windowBits < 9 || windowBits > 15) {
throw new IllegalArgumentException(
"windowBits: " + windowBits + " (expected: 9-15)");
}
if (memLevel < 1 || memLevel > 9) {
throw new IllegalArgumentException(
"memLevel: " + memLevel + " (expected: 1-9)");
}
if (wrapper == null) {
throw new NullPointerException("wrapper");
}
if (wrapper == ZlibWrapper.ZLIB_OR_NONE) {
throw new IllegalArgumentException(
"wrapper '" + ZlibWrapper.ZLIB_OR_NONE + "' is not " +
"allowed for compression.");
}
synchronized (z) {
int resultCode = z.deflateInit(compressionLevel, windowBits, memLevel,
ZlibUtil.convertWrapperType(wrapper));
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "initialization failure", resultCode);
}
}
}
/**
* Creates a new zlib encoder with the default compression level ({@code 6}),
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified preset dictionary. The wrapper is always
* {@link ZlibWrapper#ZLIB} because it is the only format that supports
* the preset dictionary.
*
* @param dictionary the preset dictionary
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(byte[] dictionary) {
this(6, dictionary);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* default window bits ({@code 15}), default memory level ({@code 8}),
* and the specified preset dictionary. The wrapper is always
* {@link ZlibWrapper#ZLIB} because it is the only format that supports
* the preset dictionary.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
* @param dictionary the preset dictionary
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(int compressionLevel, byte[] dictionary) {
this(compressionLevel, 15, 8, dictionary);
}
/**
* Creates a new zlib encoder with the specified {@code compressionLevel},
* the specified {@code windowBits}, the specified {@code memLevel},
* and the specified preset dictionary. The wrapper is always
* {@link ZlibWrapper#ZLIB} because it is the only format that supports
* the preset dictionary.
*
* @param compressionLevel
* {@code 1} yields the fastest compression and {@code 9} yields the
* best compression. {@code 0} means no compression. The default
* compression level is {@code 6}.
* @param windowBits
* The base two logarithm of the size of the history buffer. The
* value should be in the range {@code 9} to {@code 15} inclusive.
* Larger values result in better compression at the expense of
* memory usage. The default value is {@code 15}.
* @param memLevel
* How much memory should be allocated for the internal compression
* state. {@code 1} uses minimum memory and {@code 9} uses maximum
* memory. Larger values result in better and faster compression
* at the expense of memory usage. The default value is {@code 8}
* @param dictionary the preset dictionary
*
* @throws CompressionException if failed to initialize zlib
*/
public ZlibEncoder(int compressionLevel, int windowBits, int memLevel, byte[] dictionary) {
if (compressionLevel < 0 || compressionLevel > 9) {
throw new IllegalArgumentException(
"compressionLevel: " + compressionLevel + " (expected: 0-9)");
}
if (windowBits < 9 || windowBits > 15) {
throw new IllegalArgumentException(
"windowBits: " + windowBits + " (expected: 9-15)");
}
if (memLevel < 1 || memLevel > 9) {
throw new IllegalArgumentException(
"memLevel: " + memLevel + " (expected: 1-9)");
}
if (dictionary == null) {
throw new NullPointerException("dictionary");
}
synchronized (z) {
int resultCode;
resultCode = z.deflateInit(compressionLevel, windowBits, memLevel,
JZlib.W_ZLIB); // Default: ZLIB format
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "initialization failure", resultCode);
} else {
resultCode = z.deflateSetDictionary(dictionary, dictionary.length);
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "failed to set the dictionary", resultCode);
}
}
}
}
public ChannelFuture close() {
ChannelHandlerContext ctx = this.ctx;
if (ctx == null) {
throw new IllegalStateException("not added to a pipeline");
}
return finishEncode(ctx, null);
}
public boolean isClosed() {
return finished.get();
}
@Override
protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
if (!(msg instanceof ChannelBuffer) || finished.get()) {
return msg;
}
ChannelBuffer result;
synchronized (z) {
try {
// Configure input.
ChannelBuffer uncompressed = (ChannelBuffer) msg;
byte[] in = new byte[uncompressed.readableBytes()];
uncompressed.readBytes(in);
z.next_in = in;
z.next_in_index = 0;
z.avail_in = in.length;
// Configure output.
byte[] out = new byte[(int) Math.ceil(in.length * 1.001) + 12];
z.next_out = out;
z.next_out_index = 0;
z.avail_out = out.length;
// Note that Z_PARTIAL_FLUSH has been deprecated.
int resultCode = z.deflate(JZlib.Z_SYNC_FLUSH);
if (resultCode != JZlib.Z_OK) {
ZlibUtil.fail(z, "compression failure", resultCode);
}
if (z.next_out_index != 0) {
result = ctx.getChannel().getConfig().getBufferFactory().getBuffer(
uncompressed.order(), out, 0, z.next_out_index);
} else {
result = ChannelBuffers.EMPTY_BUFFER;
}
} finally {
// Deference the external references explicitly to tell the VM that
// the allocated byte arrays are temporary so that the call stack
// can be utilized.
// I'm not sure if the modern VMs do this optimization though.
z.next_in = null;
z.next_out = null;
}
}
return result;
}
@Override
public void handleDownstream(ChannelHandlerContext ctx, ChannelEvent evt)
throws Exception {
if (evt instanceof ChannelStateEvent) {
ChannelStateEvent e = (ChannelStateEvent) evt;
switch (e.getState()) {
case OPEN:
case CONNECTED:
case BOUND:
if (Boolean.FALSE.equals(e.getValue()) || e.getValue() == null) {
finishEncode(ctx, evt);
return;
}
}
}
super.handleDownstream(ctx, evt);
}
private ChannelFuture finishEncode(final ChannelHandlerContext ctx, final ChannelEvent evt) {
if (!finished.compareAndSet(false, true)) {
if (evt != null) {
ctx.sendDownstream(evt);
}
return Channels.succeededFuture(ctx.getChannel());
}
ChannelBuffer footer;
ChannelFuture future;
synchronized (z) {
try {
// Configure input.
z.next_in = EMPTY_ARRAY;
z.next_in_index = 0;
z.avail_in = 0;
// Configure output.
byte[] out = new byte[32]; // room for ADLER32 + ZLIB / CRC32 + GZIP header
z.next_out = out;
z.next_out_index = 0;
z.avail_out = out.length;
// Write the ADLER32 checksum (stream footer).
int resultCode = z.deflate(JZlib.Z_FINISH);
if (resultCode != JZlib.Z_OK && resultCode != JZlib.Z_STREAM_END) {
future = Channels.failedFuture(
ctx.getChannel(),
ZlibUtil.exception(z, "compression failure", resultCode));
footer = null;
} else if (z.next_out_index != 0) {
future = Channels.future(ctx.getChannel());
footer =
ctx.getChannel().getConfig().getBufferFactory().getBuffer(
out, 0, z.next_out_index);
} else {
// Note that we should never use a SucceededChannelFuture
// here just in case any downstream handler or a sink wants
// to notify a write error.
future = Channels.future(ctx.getChannel());
footer = ChannelBuffers.EMPTY_BUFFER;
}
} finally {
z.deflateEnd();
// Deference the external references explicitly to tell the VM that
// the allocated byte arrays are temporary so that the call stack
// can be utilized.
// I'm not sure if the modern VMs do this optimization though.
z.next_in = null;
z.next_out = null;
}
}
if (footer != null) {
Channels.write(ctx, future, footer);
}
if (evt != null) {
future.addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture future) throws Exception {
ctx.sendDownstream(evt);
}
});
}
return future;
}
public void beforeAdd(ChannelHandlerContext ctx) throws Exception {
this.ctx = ctx;
}
public void afterAdd(ChannelHandlerContext ctx) throws Exception {
// Unused
}
public void beforeRemove(ChannelHandlerContext ctx) throws Exception {
// Unused
}
public void afterRemove(ChannelHandlerContext ctx) throws Exception {
// Unused
}
}