3785ca9311
Motivation: Netty was missing support for Protobuf nano runtime targeted at weaker systems such as Android devices. Modifications: Added ProtobufDecoderNano and ProtobufDecoderNano in order to provide support for Nano runtime. modified ProtobufVarint32FrameDecoder and ProtobufLengthFieldPrepender in order to remove any on either Nano or Lite runtime by copying the code for handling Protobuf varint32 in from Protobuf library. modified Licenses and NOTICE in order to reflect the changes i made. added Protobuf Nano runtime as optional dependency Result: Netty now supports Protobuf Nano runtime.
89 lines
3.3 KiB
Java
89 lines
3.3 KiB
Java
/*
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* Copyright 2015 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 com.google.protobuf.nano.MessageNano;
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import java.util.List;
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import io.netty.buffer.ByteBuf;
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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.handler.codec.ByteToMessageDecoder;
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import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
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import io.netty.handler.codec.MessageToMessageDecoder;
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import io.netty.util.internal.ObjectUtil;
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/**
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* Decodes a received {@link ByteBuf} into a
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* <a href="http://code.google.com/p/protobuf/">Google Protocol Buffers</a>
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* {@link MessageNano}. Please note that this decoder must
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* be used with a proper {@link ByteToMessageDecoder} such as {@link LengthFieldBasedFrameDecoder}
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* if you are using a stream-based 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 ProtobufDecoderNano}(MyMessage.getDefaultInstance()));
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*
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* // Encoder
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* pipeline.addLast("frameEncoder", new {@link io.netty.handler.codec.LengthFieldPrepender}(4));
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* pipeline.addLast("protobufEncoder", new {@link ProtobufEncoderNano}());
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* </pre>
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* and then you can use a {@code MyMessage} instead of a {@link ByteBuf}
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* as a message:
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* <pre>
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* void channelRead({@link ChannelHandlerContext} ctx, Object msg) {
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* MyMessage req = (MyMessage) msg;
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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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*/
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@Sharable
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public class ProtobufDecoderNano extends MessageToMessageDecoder<ByteBuf> {
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private final Class<? extends MessageNano> clazz;
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/**
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* Creates a new instance.
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*/
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public ProtobufDecoderNano(Class<? extends MessageNano> clazz) {
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this.clazz = ObjectUtil.checkNotNull(clazz, "You must provide a Class");
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out)
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throws Exception {
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final byte[] array;
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final int offset;
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final int length = msg.readableBytes();
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if (msg.hasArray()) {
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array = msg.array();
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offset = msg.arrayOffset() + msg.readerIndex();
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} else {
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array = new byte[length];
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msg.getBytes(msg.readerIndex(), array, 0, length);
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offset = 0;
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}
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MessageNano prototype = clazz.newInstance();
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out.add(MessageNano.mergeFrom(prototype, array, offset, length));
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}
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}
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