io.netty.handler.codec.http2.Http2LocalFlowController 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:
*
* https://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.buffer.ByteBuf;
/**
* A {@link Http2FlowController} for controlling the inbound flow of {@code DATA} frames from the remote endpoint.
*/
public interface Http2LocalFlowController extends Http2FlowController {
/**
* Sets the writer to be use for sending {@code WINDOW_UPDATE} frames. This must be called before any flow
* controlled data is received.
*
* @param frameWriter the HTTP/2 frame writer.
*/
Http2LocalFlowController frameWriter(Http2FrameWriter frameWriter);
/**
* Receives an inbound {@code DATA} frame from the remote endpoint and applies flow control policies to it for both
* the {@code stream} as well as the connection. If any flow control policies have been violated, an exception is
* raised immediately, otherwise the frame is considered to have "passed" flow control.
*
* If {@code stream} is {@code null} or closed, flow control should only be applied to the connection window and the
* bytes are immediately consumed.
*
* @param stream the subject stream for the received frame. The connection stream object must not be used. If {@code
* stream} is {@code null} or closed, flow control should only be applied to the connection window and the bytes are
* immediately consumed.
* @param data payload buffer for the frame.
* @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
* 256 (inclusive).
* @param endOfStream Indicates whether this is the last frame to be sent from the remote endpoint for this stream.
* @throws Http2Exception if any flow control errors are encountered.
*/
void receiveFlowControlledFrame(Http2Stream stream, ByteBuf data, int padding,
boolean endOfStream) throws Http2Exception;
/**
* Indicates that the application has consumed a number of bytes for the given stream and is therefore ready to
* receive more data from the remote endpoint. The application must consume any bytes that it receives or the flow
* control window will collapse. Consuming bytes enables the flow controller to send {@code WINDOW_UPDATE} to
* restore a portion of the flow control window for the stream.
*
* If {@code stream} is {@code null} or closed (i.e. {@link Http2Stream#state()} method returns {@link
* Http2Stream.State#CLOSED}), calling this method has no effect.
*
* @param stream the stream for which window space should be freed. The connection stream object must not be used.
* If {@code stream} is {@code null} or closed (i.e. {@link Http2Stream#state()} method returns {@link
* Http2Stream.State#CLOSED}), calling this method has no effect.
* @param numBytes the number of bytes to be returned to the flow control window.
* @return true if a {@code WINDOW_UPDATE} was sent, false otherwise.
* @throws Http2Exception if the number of bytes returned exceeds the {@link #unconsumedBytes(Http2Stream)} for the
* stream.
*/
boolean consumeBytes(Http2Stream stream, int numBytes) throws Http2Exception;
/**
* The number of bytes for the given stream that have been received but not yet consumed by the
* application.
*
* @param stream the stream for which window space should be freed.
* @return the number of unconsumed bytes for the stream.
*/
int unconsumedBytes(Http2Stream stream);
/**
* Get the initial flow control window size for the given stream. This quantity is measured in number of bytes. Note
* the unavailable window portion can be calculated by {@link #initialWindowSize()} - {@link
* #windowSize(Http2Stream)}.
*/
int initialWindowSize(Http2Stream stream);
}