1 /* 2 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package jdk.incubator.http; 26 27 import java.lang.System.Logger.Level; 28 import jdk.incubator.http.internal.frame.SettingsFrame; 29 import jdk.incubator.http.internal.frame.WindowUpdateFrame; 30 import jdk.incubator.http.internal.common.Utils; 31 32 import java.util.concurrent.atomic.AtomicInteger; 33 34 abstract class WindowUpdateSender { 35 36 final static boolean DEBUG = Utils.DEBUG; 37 final System.Logger debug = 38 Utils.getDebugLogger(this::dbgString, DEBUG); 39 40 final int limit; 41 final Http2Connection connection; 42 final AtomicInteger received = new AtomicInteger(0); 43 44 WindowUpdateSender(Http2Connection connection) { 45 this(connection, connection.clientSettings.getParameter(SettingsFrame.INITIAL_WINDOW_SIZE)); 46 } 47 48 WindowUpdateSender(Http2Connection connection, int initWindowSize) { 49 this(connection, connection.getMaxReceiveFrameSize(), initWindowSize); 50 } 51 52 WindowUpdateSender(Http2Connection connection, int maxFrameSize, int initWindowSize) { 53 this.connection = connection; 54 int v0 = Math.max(0, initWindowSize - maxFrameSize); 55 int v1 = (initWindowSize + (maxFrameSize - 1)) / maxFrameSize; 56 v1 = v1 * maxFrameSize / 2; 57 // send WindowUpdate heuristic: 58 // - we got data near half of window size 59 // or 60 // - remaining window size reached max frame size. 61 limit = Math.min(v0, v1); 62 } 63 64 abstract int getStreamId(); 65 66 void update(int delta) { 67 debug.log(Level.DEBUG, "update: %d", delta); 68 if (received.addAndGet(delta) > limit) { 69 synchronized (this) { 70 int tosend = received.get(); 71 if( tosend > limit) { 72 received.getAndAdd(-tosend); 73 sendWindowUpdate(tosend); 74 } 75 } 76 } 77 } 78 79 void sendWindowUpdate(int delta) { 80 debug.log(Level.DEBUG, "sending window update: %d", delta); 81 connection.sendUnorderedFrame(new WindowUpdateFrame(getStreamId(), delta)); 82 } 83 84 String dbgString() { 85 return "WindowUpdateSender(stream: " + getStreamId() + ")"; 86 } 87 88 }