io.netty.handler.codec.http2.Http2FlowController Maven / Gradle / Ivy
/*
* Copyright 2014 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.channel.ChannelHandlerContext;
import io.netty.util.internal.UnstableApi;
/**
* Base interface for all HTTP/2 flow controllers.
*/
@UnstableApi
public interface Http2FlowController {
/**
* Set the {@link ChannelHandlerContext} for which to apply flow control on.
*
* This must be called to properly initialize the {@link Http2FlowController}.
* Not calling this is considered a programming error.
* @param ctx The {@link ChannelHandlerContext} for which to apply flow control on.
* @throws Http2Exception if any protocol-related error occurred.
*/
void channelHandlerContext(ChannelHandlerContext ctx) throws Http2Exception;
/**
* Sets the connection-wide initial flow control window and updates all stream windows (but not the connection
* stream window) by the delta.
*
* Represents the value for
* SETTINGS_INITIAL_WINDOW_SIZE. This method should
* only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
*
* @param newWindowSize the new initial window size.
* @throws Http2Exception thrown if any protocol-related error occurred.
*/
void initialWindowSize(int newWindowSize) throws Http2Exception;
/**
* Gets the connection-wide initial flow control window size that is used as the basis for new stream flow
* control windows.
*
* Represents the value for
* SETTINGS_INITIAL_WINDOW_SIZE. The initial value
* returned by this method must be {@link Http2CodecUtil#DEFAULT_WINDOW_SIZE}.
*/
int initialWindowSize();
/**
* Get the portion of the flow control window for the given stream that is currently available for sending/receiving
* frames which are subject to flow control. This quantity is measured in number of bytes.
*/
int windowSize(Http2Stream stream);
/**
* Increments the size of the stream's flow control window by the given delta.
*
* In the case of a {@link Http2RemoteFlowController} this is called upon receipt of a
* {@code WINDOW_UPDATE} frame from the remote endpoint to mirror the changes to the window
* size.
*
* For a {@link Http2LocalFlowController} this can be called to request the expansion of the
* window size published by this endpoint. It is up to the implementation, however, as to when a
* {@code WINDOW_UPDATE} is actually sent.
*
* @param stream The subject stream. Use {@link Http2Connection#connectionStream()} for
* requesting the size of the connection window.
* @param delta the change in size of the flow control window.
* @throws Http2Exception thrown if a protocol-related error occurred.
*/
void incrementWindowSize(Http2Stream stream, int delta) throws Http2Exception;
}