netty5/codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2HeadersFrame.java

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/*
* Copyright 2016 The Netty Project
*
* The Netty Project 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 io.netty.handler.codec.http2;
import io.netty.util.internal.StringUtil;
import io.netty.util.internal.UnstableApi;
import static io.netty.handler.codec.http2.Http2CodecUtil.verifyPadding;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
/**
* The default {@link Http2HeadersFrame} implementation.
*/
@UnstableApi
public final class DefaultHttp2HeadersFrame extends AbstractHttp2StreamFrame implements Http2HeadersFrame {
private final Http2Headers headers;
private final boolean endStream;
private final int padding;
/**
* Equivalent to {@code new DefaultHttp2HeadersFrame(headers, false)}.
*
* @param headers the non-{@code null} headers to send
*/
public DefaultHttp2HeadersFrame(Http2Headers headers) {
this(headers, false);
}
/**
* Equivalent to {@code new DefaultHttp2HeadersFrame(headers, endStream, 0)}.
*
* @param headers the non-{@code null} headers to send
*/
public DefaultHttp2HeadersFrame(Http2Headers headers, boolean endStream) {
this(headers, endStream, 0);
}
/**
* Construct a new headers message.
*
* @param headers the non-{@code null} headers to send
* @param endStream whether these headers should terminate the stream
* @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
* 256 (inclusive).
*/
public DefaultHttp2HeadersFrame(Http2Headers headers, boolean endStream, int padding) {
this.headers = checkNotNull(headers, "headers");
this.endStream = endStream;
verifyPadding(padding);
this.padding = padding;
}
@Override
public DefaultHttp2HeadersFrame stream(Http2FrameStream stream) {
HTTP/2 Child Channel and FrameCodec Feature Parity. Motivation: This PR (unfortunately) does 4 things: 1) Add outbound flow control to the Http2MultiplexCodec: The HTTP/2 child channel API should interact with HTTP/2 outbound/remote flow control. That is, if a H2 stream used up all its flow control window, the corresponding child channel should be marked unwritable and a writability-changed event should be fired. Similarly, a unwritable child channel should be marked writable and a writability-event should be fired, once a WINDOW_UPDATE frame has been received. The changes are (mostly) contained in ChannelOutboundBuffer, AbstractHttp2StreamChannel and Http2MultiplexCodec. 2) Introduce a Http2Stream2 object, that is used instead of stream identifiers on stream frames. A Http2Stream2 object allows an application to attach state to it, and so a application handler no longer needs to maintain stream state (i.e. in a map(id -> state)) himself. 3) Remove stream state events, which are no longer necessary due to the introduction of Http2Stream2. Also those stream state events have been found hard and complex to work with, when porting gRPC to the Http2FrameCodec. 4) Add support for HTTP/2 frames that have not yet been implemented, like PING and SETTINGS. Also add a Http2FrameCodecBuilder that exposes options from the Http2ConnectionHandler API that couldn't else be used with the frame codec, like buffering outbound streams, window update ratio, frame logger, etc. Modifications: 1) A child channel's writability and a H2 stream's outbound flow control window interact, as described in the motivation. A channel handler is free to ignore the channel's writability, in which case the parent channel is reponsible for buffering writes until a WINDOW_UPDATE is received. The connection-level flow control window is ignored for now. That is, a child channel's writability is only affected by the stream-level flow control window. So a child channel could be marked writable, even though the connection-level flow control window is zero. 2) Modify Http2StreamFrame and the Http2FrameCodec to take a Http2Stream2 object intstead of a primitive integer. Introduce a special Http2ChannelDuplexHandler that has newStream() and forEachActiveStream() methods. It's recommended for a user to extend from this handler, to use those advanced features. 3) As explained in the documentation, a new inbound stream active can be detected by checking if the Http2Stream2.managedState() of a Http2HeadersFrame is null. An outbound stream active can be detected by adding a listener to the ChannelPromise of the write of the first Http2HeadersFrame. A stream closed event can be listened to by adding a listener to the Http2Stream2.closeFuture(). 4) Add a simple Http2FrameCodecBuilder and implement the missing frame types. Result: 1) The Http2MultiplexCodec supports outbound flow control. 2) The Http2FrameCodec API makes it easy for a user to manage custom stream specific state and to create new outbound streams. 3) The Http2FrameCodec API is much cleaner and easier to work with. Hacks like the ChannelCarryingHeadersFrame are no longer necessary. 4) The Http2FrameCodec now also supports PING and SETTINGS frames. The Http2FrameCodecBuilder allows the Http2FrameCodec to use some of the rich features of the Http2ConnectionHandler API.
2016-08-23 13:03:39 +02:00
super.stream(stream);
return this;
}
@Override
public String name() {
return "HEADERS";
}
@Override
public Http2Headers headers() {
return headers;
}
@Override
public boolean isEndStream() {
return endStream;
}
@Override
public int padding() {
return padding;
}
@Override
public String toString() {
return StringUtil.simpleClassName(this) + "(stream=" + stream() + ", headers=" + headers
+ ", endStream=" + endStream + ", padding=" + padding + ')';
}
@Override
public boolean equals(Object o) {
if (!(o instanceof DefaultHttp2HeadersFrame)) {
return false;
}
DefaultHttp2HeadersFrame other = (DefaultHttp2HeadersFrame) o;
return super.equals(other) && headers.equals(other.headers)
&& endStream == other.endStream && padding == other.padding;
}
@Override
public int hashCode() {
int hash = super.hashCode();
hash = hash * 31 + headers.hashCode();
hash = hash * 31 + (endStream ? 0 : 1);
hash = hash * 31 + padding;
return hash;
}
}