ebfc4513e0
Please note that the build will fail at the moment due to various checkstyle violations which should be fixed soon
115 lines
4.4 KiB
Java
115 lines
4.4 KiB
Java
/*
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* Copyright 2011 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.protobuf;
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import io.netty.buffer.ChannelBuffer;
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import io.netty.buffer.ChannelBufferInputStream;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelHandler.Sharable;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelPipeline;
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import io.netty.channel.MessageEvent;
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import io.netty.handler.codec.frame.FrameDecoder;
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import io.netty.handler.codec.frame.LengthFieldBasedFrameDecoder;
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import io.netty.handler.codec.frame.LengthFieldPrepender;
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import io.netty.handler.codec.oneone.OneToOneDecoder;
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import com.google.protobuf.ExtensionRegistry;
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import com.google.protobuf.Message;
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import com.google.protobuf.MessageLite;
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/**
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* Decodes a received {@link ChannelBuffer} into a
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* <a href="http://code.google.com/p/protobuf/">Google Protocol Buffers</a>
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* {@link Message} and {@link MessageLite}. Please note that this decoder must
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* be used with a proper {@link FrameDecoder} such as {@link ProtobufVarint32FrameDecoder}
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* or {@link LengthFieldBasedFrameDecoder} if you are using a stream-based
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* transport such as TCP/IP. A typical setup for TCP/IP would be:
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* <pre>
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* {@link ChannelPipeline} pipeline = ...;
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*
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* // Decoders
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* pipeline.addLast("frameDecoder",
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* new {@link LengthFieldBasedFrameDecoder}(1048576, 0, 4, 0, 4));
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* pipeline.addLast("protobufDecoder",
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* new {@link ProtobufDecoder}(MyMessage.getDefaultInstance()));
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*
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* // Encoder
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* pipeline.addLast("frameEncoder", new {@link LengthFieldPrepender}(4));
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* pipeline.addLast("protobufEncoder", new {@link ProtobufEncoder}());
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* </pre>
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* and then you can use a {@code MyMessage} instead of a {@link ChannelBuffer}
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* as a message:
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* <pre>
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* void messageReceived({@link ChannelHandlerContext} ctx, {@link MessageEvent} e) {
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* MyMessage req = (MyMessage) e.getMessage();
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* MyMessage res = MyMessage.newBuilder().setText(
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* "Did you say '" + req.getText() + "'?").build();
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* ch.write(res);
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* }
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* </pre>
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* @apiviz.landmark
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*/
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@Sharable
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public class ProtobufDecoder extends OneToOneDecoder {
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private final MessageLite prototype;
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private final ExtensionRegistry extensionRegistry;
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/**
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* Creates a new instance.
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*/
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public ProtobufDecoder(MessageLite prototype) {
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this(prototype, null);
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}
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public ProtobufDecoder(MessageLite prototype, ExtensionRegistry extensionRegistry) {
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if (prototype == null) {
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throw new NullPointerException("prototype");
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}
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this.prototype = prototype.getDefaultInstanceForType();
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this.extensionRegistry = extensionRegistry;
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}
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@Override
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protected Object decode(
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ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
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if (!(msg instanceof ChannelBuffer)) {
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return msg;
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}
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ChannelBuffer buf = (ChannelBuffer) msg;
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if (buf.hasArray()) {
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final int offset = buf.readerIndex();
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if (extensionRegistry == null) {
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return prototype.newBuilderForType().mergeFrom(
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buf.array(), buf.arrayOffset() + offset, buf.readableBytes()).build();
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} else {
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return prototype.newBuilderForType().mergeFrom(
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buf.array(), buf.arrayOffset() + offset, buf.readableBytes(), extensionRegistry).build();
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}
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} else {
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if (extensionRegistry == null) {
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return prototype.newBuilderForType().mergeFrom(
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new ChannelBufferInputStream((ChannelBuffer) msg)).build();
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} else {
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return prototype.newBuilderForType().mergeFrom(
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new ChannelBufferInputStream((ChannelBuffer) msg), extensionRegistry).build();
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}
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}
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}
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}
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