1 /*
2 * Copyright 2014 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5 * "License"); you may not use this file except in compliance with the License. You may obtain a
6 * copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software distributed under the License
11 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12 * or implied. See the License for the specific language governing permissions and limitations under
13 * the License.
14 */
15 package io.netty5.handler.codec.http2;
16
17 import io.netty5.buffer.api.Buffer;
18 import io.netty5.util.internal.UnstableApi;
19
20 /**
21 * A {@link Http2FlowController} for controlling the inbound flow of {@code DATA} frames from the remote endpoint.
22 */
23 @UnstableApi
24 public interface Http2LocalFlowController extends Http2FlowController {
25 /**
26 * Sets the writer to be use for sending {@code WINDOW_UPDATE} frames. This must be called before any flow
27 * controlled data is received.
28 *
29 * @param frameWriter the HTTP/2 frame writer.
30 */
31 Http2LocalFlowController frameWriter(Http2FrameWriter frameWriter);
32
33 /**
34 * Receives an inbound {@code DATA} frame from the remote endpoint and applies flow control policies to it for both
35 * the {@code stream} as well as the connection. If any flow control policies have been violated, an exception is
36 * raised immediately, otherwise the frame is considered to have "passed" flow control.
37 * <p/>
38 * If {@code stream} is {@code null} or closed, flow control should only be applied to the connection window and the
39 * bytes are immediately consumed.
40 *
41 * @param stream the subject stream for the received frame. The connection stream object must not be used. If {@code
42 * stream} is {@code null} or closed, flow control should only be applied to the connection window and the bytes are
43 * immediately consumed.
44 * @param data payload buffer for the frame.
45 * @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
46 * 256 (inclusive).
47 * @param endOfStream Indicates whether this is the last frame to be sent from the remote endpoint for this stream.
48 * @throws Http2Exception if any flow control errors are encountered.
49 */
50 void receiveFlowControlledFrame(Http2Stream stream, Buffer data, int padding,
51 boolean endOfStream) throws Http2Exception;
52
53 /**
54 * Indicates that the application has consumed a number of bytes for the given stream and is therefore ready to
55 * receive more data from the remote endpoint. The application must consume any bytes that it receives or the flow
56 * control window will collapse. Consuming bytes enables the flow controller to send {@code WINDOW_UPDATE} to
57 * restore a portion of the flow control window for the stream.
58 * <p/>
59 * If {@code stream} is {@code null} or closed (i.e. {@link Http2Stream#state()} method returns {@link
60 * Http2Stream.State#CLOSED}), calling this method has no effect.
61 *
62 * @param stream the stream for which window space should be freed. The connection stream object must not be used.
63 * If {@code stream} is {@code null} or closed (i.e. {@link Http2Stream#state()} method returns {@link
64 * Http2Stream.State#CLOSED}), calling this method has no effect.
65 * @param numBytes the number of bytes to be returned to the flow control window.
66 * @return true if a {@code WINDOW_UPDATE} was sent, false otherwise.
67 * @throws Http2Exception if the number of bytes returned exceeds the {@link #unconsumedBytes(Http2Stream)} for the
68 * stream.
69 */
70 boolean consumeBytes(Http2Stream stream, int numBytes) throws Http2Exception;
71
72 /**
73 * The number of bytes for the given stream that have been received but not yet consumed by the
74 * application.
75 *
76 * @param stream the stream for which window space should be freed.
77 * @return the number of unconsumed bytes for the stream.
78 */
79 int unconsumedBytes(Http2Stream stream);
80
81 /**
82 * Get the initial flow control window size for the given stream. This quantity is measured in number of bytes. Note
83 * the unavailable window portion can be calculated by {@link #initialWindowSize()} - {@link
84 * #windowSize(Http2Stream)}.
85 */
86 int initialWindowSize(Http2Stream stream);
87 }