Relates issue: NETTY-80 Compression codec

* Initial implementation of jzlib based zlib compression handler

NOTICE.txt

@@ -57,6 +57,14 @@ interchange format, which can be obtained at:
   * HOMEPAGE:
     * http://code.google.com/p/protobuf/
 
+This product optionally depends on 'JZlib', a re-implementation of zlib in pure
+Java, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.jzlib.txt (BSD Style License)
+  * HOMEPAGE:
+    * http://www.jcraft.com/jzlib/
+
 This product optionally depends on 'SLF4J', a simple logging facade for Java,
 which can be obtained at:
 

license/LICENSE.jzlib.txt

@@ -0,0 +1,26 @@
+Copyright (c) 2000,2001,2002,2003,2004 ymnk, JCraft,Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  1. Redistributions of source code must retain the above copyright notice,
+     this list of conditions and the following disclaimer.
+
+  2. Redistributions in binary form must reproduce the above copyright 
+     notice, this list of conditions and the following disclaimer in 
+     the documentation and/or other materials provided with the distribution.
+
+  3. The names of the authors may not be used to endorse or promote products
+     derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
+INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+

pom.xml

@@ -77,6 +77,15 @@
       <optional>true</optional>
     </dependency>
 
+    <!-- JCraft JZlib - completely optional -->
+    <dependency>
+      <groupId>com.jcraft</groupId>
+      <artifactId>jzlib</artifactId>
+      <version>1.0.7</version>
+      <scope>compile</scope>
+      <optional>true</optional>
+    </dependency>
+
     <!-- Servlet API - completely optional -->
     <dependency>
       <groupId>javax.servlet</groupId>

src/main/java/org/jboss/netty/handler/codec/compression/ZlibDecoder.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.ChannelPipelineCoverage;
+import org.jboss.netty.handler.codec.oneone.OneToOneDecoder;
+
+import com.jcraft.jzlib.JZlib;
+import com.jcraft.jzlib.ZStream;
+import com.jcraft.jzlib.ZStreamException;
+
+/**
+ * Decompresses a {@link ChannelBuffer} using the deflate algorithm.
+ *
+ * @author The Netty Project ([email protected])
+ * @author Trustin Lee ([email protected])
+ * @version $Rev$, $Date$
+ */
+@ChannelPipelineCoverage("one")
+public class ZlibDecoder extends OneToOneDecoder {
+
+    private final ZStream z = new ZStream();
+
+    // TODO Auto-detect wrappers (zlib, gzip, nowrapper as a fallback)
+
+    /**
+     * Creates a new instance.
+     */
+    public ZlibDecoder() {
+        z.inflateInit();
+    }
+
+    @Override
+    protected Object decode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
+        if (!(msg instanceof ChannelBuffer)) {
+            return msg;
+        }
+
+        try {
+            // Configure input.
+            ChannelBuffer compressed = (ChannelBuffer) msg;
+            byte[] in = new byte[compressed.readableBytes()];
+            compressed.readBytes(in);
+            z.next_in = in;
+            z.next_in_index = 0;
+            z.avail_in = in.length;
+
+            // Configure output.
+            byte[] out = new byte[in.length << 1];
+            ChannelBuffer decompressed = ChannelBuffers.dynamicBuffer(
+                    compressed.order(), out.length,
+                    ctx.getChannel().getConfig().getBufferFactory());
+            z.next_out = out;
+            z.next_out_index = 0;
+            z.avail_out = out.length;
+
+            do {
+                // Decompress 'in' into 'out'
+                int resultCode = z.inflate(JZlib.Z_SYNC_FLUSH);
+                switch (resultCode) {
+                case JZlib.Z_OK:
+                case JZlib.Z_BUF_ERROR:
+                    decompressed.writeBytes(out, 0, z.next_out_index);
+                    z.next_out_index = 0;
+                    z.avail_out = out.length;
+                    break;
+                default:
+                    throw new ZStreamException(
+                            "decompression failure (" + resultCode + ")" +
+                            (z.msg != null? ": " + z.msg : ""));
+                }
+            } while (z.avail_in > 0);
+
+            if (decompressed.writerIndex() != 0) { // readerIndex is always 0
+                return decompressed;
+            } else {
+                return 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;
+        }
+    }
+}

src/main/java/org/jboss/netty/handler/codec/compression/ZlibEncoder.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.ChannelPipelineCoverage;
+import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
+
+import com.jcraft.jzlib.JZlib;
+import com.jcraft.jzlib.ZStream;
+import com.jcraft.jzlib.ZStreamException;
+
+/**
+ * Compresses a {@link ChannelBuffer} using the deflate algorithm.
+ *
+ * @author The Netty Project ([email protected])
+ * @author Trustin Lee ([email protected])
+ * @version $Rev$, $Date$
+ */
+@ChannelPipelineCoverage("one")
+public class ZlibEncoder extends OneToOneEncoder {
+
+    private final ZStream z = new ZStream();
+
+    // TODO 'do not compress' once option
+    // TODO support three wrappers - zlib (default), gzip (unsupported by jzlib, but easy to implement), nowrap
+
+    /**
+     * Creates a new GZip encoder with the default compression level
+     * ({@link JZlib#Z_DEFAULT_COMPRESSION}).
+     */
+    public ZlibEncoder() {
+        this(JZlib.Z_DEFAULT_COMPRESSION);
+    }
+
+    /**
+     * Creates a new GZip encoder with the specified {@code compressionLevel}.
+     *
+     * @param compressionLevel
+     *        the compression level, as specified in {@link JZlib}.
+     *        The common values are
+     *        {@link JZlib#Z_BEST_COMPRESSION},
+     *        {@link JZlib#Z_BEST_SPEED},
+     *        {@link JZlib#Z_DEFAULT_COMPRESSION}, and
+     *        {@link JZlib#Z_NO_COMPRESSION}.
+     */
+    public ZlibEncoder(int compressionLevel) {
+        z.deflateInit(compressionLevel, false); // Default: ZLIB format
+    }
+
+    @Override
+    protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
+        if (!(msg instanceof ChannelBuffer)) {
+            return msg;
+        }
+
+        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) {
+                throw new ZStreamException(
+                        "compression failure (" + resultCode + ")" +
+                        (z.msg != null? ": " + z.msg : ""));
+            }
+
+            if (z.next_out_index != 0) {
+                return ctx.getChannel().getConfig().getBufferFactory().getBuffer(
+                        uncompressed.order(), out, 0, z.next_out_index);
+            } else {
+                return 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;
+        }
+    }
+}

src/main/java/org/jboss/netty/handler/codec/compression/package-info.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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.
+ */
+
+/**
+ * Encoder and decoder which compresses and decompresses {@link ChannelBuffer}s
+ * in a compression format such as <a href="http://en.wikipedia.org/wiki/Zlib">zlib</a>,
+ * <a href="http://en.wikipedia.org/wiki/Gzip">gzip</a>, and
+ * <a href="http://en.wikipedia.org/wiki/Bzip2">bzip2</a>.
+ *
+ * @apiviz.exclude \.codec\.(?!compression)[a-z0-9]+\.
+ */
+package org.jboss.netty.handler.codec.compression;
+// TODO Implement bzip2 handlers