1 /* 2 * Copyright (c) 2015, 2016, 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 jdk.incubator.http.internal.frame.SettingsFrame; 28 import jdk.incubator.http.internal.frame.WindowUpdateFrame; 29 30 import java.util.concurrent.atomic.AtomicInteger; 31 32 abstract class WindowUpdateSender { 33 34 35 final int limit; 36 final Http2Connection connection; 37 final AtomicInteger received = new AtomicInteger(0); 38 39 WindowUpdateSender(Http2Connection connection) { 40 this(connection, connection.clientSettings.getParameter(SettingsFrame.INITIAL_WINDOW_SIZE)); 41 } 42 43 WindowUpdateSender(Http2Connection connection, int initWindowSize) { 44 this(connection, connection.getMaxReceiveFrameSize(), initWindowSize); 45 } 46 47 WindowUpdateSender(Http2Connection connection, int maxFrameSize, int initWindowSize) { 48 this.connection = connection; 49 int v0 = Math.max(0, initWindowSize - maxFrameSize); 50 int v1 = (initWindowSize + (maxFrameSize - 1)) / maxFrameSize; 51 v1 = v1 * maxFrameSize / 2; 52 // send WindowUpdate heuristic: 53 // - we got data near half of window size 54 // or 55 // - remaining window size reached max frame size. 56 limit = Math.min(v0, v1); 57 } 58 59 abstract int getStreamId(); 60 61 void update(int delta) { 62 if (received.addAndGet(delta) > limit) { 63 synchronized (this) { 64 int tosend = received.get(); 65 if( tosend > limit) { 66 received.getAndAdd(-tosend); 67 sendWindowUpdate(tosend); 68 } 69 } 70 } 71 } 72 73 void sendWindowUpdate(int delta) { 74 connection.sendUnorderedFrame(new WindowUpdateFrame(getStreamId(), delta)); 75 } 76 77 78 }