df46a349e0
Motivation: Http2MultiplexCodec and Http2MultiplexHandler had a very strong coupling with Http2FrameCodec which we can reduce easily. The end-goal should be to have no coupling at all. Modifications: - Reduce coupling by move some common logic to Http2CodecUtil - Move logic to check if a stream may have existed before to Http2FrameCodec - Use ArrayDeque as replacement for custom double-linked-list which makes the code a lot more readable - Use WindowUpdateFrame to signal consume bytes (just as users do when they use Http2FrameCodec directly) Result: Less coupling and cleaner code.
95 lines
3.4 KiB
Java
95 lines
3.4 KiB
Java
/*
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* Copyright 2016 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.http2;
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import io.netty.channel.ChannelDuplexHandler;
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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.util.internal.StringUtil;
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import io.netty.util.internal.UnstableApi;
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/**
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* A {@link ChannelDuplexHandler} providing additional functionality for HTTP/2. Specifically it allows to:
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* <ul>
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* <li>Create new outbound streams using {@link #newStream()}.</li>
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* <li>Iterate over all active streams using {@link #forEachActiveStream(Http2FrameStreamVisitor)}.</li>
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* </ul>
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*
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* <p>The {@link Http2FrameCodec} is required to be part of the {@link ChannelPipeline} before this handler is added,
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* or else an {@link IllegalStateException} will be thrown.
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*/
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@UnstableApi
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public abstract class Http2ChannelDuplexHandler extends ChannelDuplexHandler {
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private volatile Http2FrameCodec frameCodec;
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@Override
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public final void handlerAdded(ChannelHandlerContext ctx) throws Exception {
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frameCodec = requireHttp2FrameCodec(ctx);
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handlerAdded0(ctx);
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}
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protected void handlerAdded0(@SuppressWarnings("unused") ChannelHandlerContext ctx) throws Exception {
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// NOOP
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}
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@Override
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public final void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
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try {
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handlerRemoved0(ctx);
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} finally {
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frameCodec = null;
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}
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}
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protected void handlerRemoved0(@SuppressWarnings("unused") ChannelHandlerContext ctx) throws Exception {
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// NOOP
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}
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/**
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* Creates a new {@link Http2FrameStream} object.
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*
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* <p>This method is <em>thread-safe</em>.
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*/
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public final Http2FrameStream newStream() {
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Http2FrameCodec codec = frameCodec;
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if (codec == null) {
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throw new IllegalStateException(StringUtil.simpleClassName(Http2FrameCodec.class) + " not found." +
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" Has the handler been added to a pipeline?");
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}
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return codec.newStream();
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}
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/**
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* Allows to iterate over all currently active streams.
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*
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* <p>This method may only be called from the eventloop thread.
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*/
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protected final void forEachActiveStream(Http2FrameStreamVisitor streamVisitor) throws Http2Exception {
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frameCodec.forEachActiveStream(streamVisitor);
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}
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private static Http2FrameCodec requireHttp2FrameCodec(ChannelHandlerContext ctx) {
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ChannelHandlerContext frameCodecCtx = ctx.pipeline().context(Http2FrameCodec.class);
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if (frameCodecCtx == null) {
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throw new IllegalArgumentException(Http2FrameCodec.class.getSimpleName()
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+ " was not found in the channel pipeline.");
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}
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return (Http2FrameCodec) frameCodecCtx.handler();
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}
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}
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