0e4c073bcf
Motivation: ByteToMessageDecoder requires using an intermediate List to put results into. This intermediate list adds overhead (memory/CPU) which grows as the number of objects increases. This overhead can be avoided by directly propagating events through the ChannelPipeline via ctx.fireChannelRead(...). This also makes the semantics more clear and allows us to keep track if we need to call ctx.read() in all cases. Modifications: - Remove List from the method signature of ByteToMessageDecoder.decode(...) and decodeLast(...) - Adjust all sub-classes - Adjust unit tests - Fix javadocs. Result: Adjust ByteToMessageDecoder as noted in https://github.com/netty/netty/issues/8525.
65 lines
2.4 KiB
Java
65 lines
2.4 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.dns;
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import io.netty.channel.ChannelHandler;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.socket.DatagramPacket;
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import io.netty.handler.codec.MessageToMessageDecoder;
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import io.netty.util.internal.UnstableApi;
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import java.net.InetSocketAddress;
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/**
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* Decodes a {@link DatagramPacket} into a {@link DatagramDnsResponse}.
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*/
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@UnstableApi
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@ChannelHandler.Sharable
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public class DatagramDnsResponseDecoder extends MessageToMessageDecoder<DatagramPacket> {
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private final DnsResponseDecoder<InetSocketAddress> responseDecoder;
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/**
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* Creates a new decoder with {@linkplain DnsRecordDecoder#DEFAULT the default record decoder}.
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*/
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public DatagramDnsResponseDecoder() {
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this(DnsRecordDecoder.DEFAULT);
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}
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/**
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* Creates a new decoder with the specified {@code recordDecoder}.
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*/
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public DatagramDnsResponseDecoder(DnsRecordDecoder recordDecoder) {
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this.responseDecoder = new DnsResponseDecoder<InetSocketAddress>(recordDecoder) {
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@Override
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protected DnsResponse newResponse(InetSocketAddress sender, InetSocketAddress recipient,
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int id, DnsOpCode opCode, DnsResponseCode responseCode) {
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return new DatagramDnsResponse(sender, recipient, id, opCode, responseCode);
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}
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};
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
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DnsResponse response = decodeResponse(ctx, packet);
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ctx.fireChannelRead(response);
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}
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protected DnsResponse decodeResponse(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
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return responseDecoder.decode(packet.sender(), packet.recipient(), packet.content());
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}
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}
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