1 /*
2 * Copyright 2021 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a 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
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.handler.codec.quic;
17
18 import io.netty.util.internal.ObjectUtil;
19
20 /**
21 * Allows to configure a strategy for when flushes should be happening.
22 */
23 public interface FlushStrategy {
24
25 /**
26 * Default {@link FlushStrategy} implementation.
27 */
28 FlushStrategy DEFAULT = afterNumBytes(20 * Quic.MAX_DATAGRAM_SIZE);
29
30 /**
31 * Returns {@code true} if a flush should happen now, {@code false} otherwise.
32 *
33 * @param numPackets the number of packets that were written since the last flush.
34 * @param numBytes the number of bytes that were written since the last flush.
35 * @return {@code true} if a flush should be done now, {@code false} otherwise.
36 */
37 boolean shouldFlushNow(int numPackets, int numBytes);
38
39 /**
40 * Implementation that flushes after a number of bytes.
41 *
42 * @param bytes the number of bytes after which we should issue a flush.
43 * @return the {@link FlushStrategy}.
44 */
45 static FlushStrategy afterNumBytes(int bytes) {
46 ObjectUtil.checkPositive(bytes, "bytes");
47 return (numPackets, numBytes) -> numBytes > bytes;
48 }
49
50 /**
51 * Implementation that flushes after a number of packets.
52 *
53 * @param packets the number of packets after which we should issue a flush.
54 * @return the {@link FlushStrategy}.
55 */
56 static FlushStrategy afterNumPackets(int packets) {
57 ObjectUtil.checkPositive(packets, "packets");
58 return (numPackets, numBytes) -> numPackets > packets;
59 }
60 }