1 /* 2 * Copyright (c) 2015, 2018, 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 26 package jdk.internal.net.http; 27 28 import jdk.internal.net.http.common.FlowTube; 29 import jdk.internal.net.http.common.Logger; 30 import jdk.internal.net.http.frame.SettingsFrame; 31 import jdk.internal.net.http.frame.WindowUpdateFrame; 32 import jdk.internal.net.http.common.Utils; 33 import java.util.concurrent.atomic.AtomicInteger; 34 35 abstract class WindowUpdateSender { 36 37 final Logger debug = 38 Utils.getDebugLogger(this::dbgString, Utils.DEBUG); 39 40 final int limit; 41 final Http2Connection connection; 42 final AtomicInteger received = new AtomicInteger(); 43 WindowUpdateSender(Http2Connection connection)44 WindowUpdateSender(Http2Connection connection) { 45 this(connection, connection.clientSettings.getParameter(SettingsFrame.INITIAL_WINDOW_SIZE)); 46 } 47 WindowUpdateSender(Http2Connection connection, int initWindowSize)48 WindowUpdateSender(Http2Connection connection, int initWindowSize) { 49 this(connection, connection.getMaxReceiveFrameSize(), initWindowSize); 50 } 51 WindowUpdateSender(Http2Connection connection, int maxFrameSize, int initWindowSize)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 if (debug.on()) 63 debug.log("maxFrameSize=%d, initWindowSize=%d, limit=%d", 64 maxFrameSize, initWindowSize, limit); 65 } 66 getStreamId()67 abstract int getStreamId(); 68 update(int delta)69 void update(int delta) { 70 int rcv = received.addAndGet(delta); 71 if (debug.on()) debug.log("update: %d, received: %d, limit: %d", delta, rcv, limit); 72 if (rcv > limit) { 73 synchronized (this) { 74 int tosend = received.get(); 75 if( tosend > limit) { 76 received.getAndAdd(-tosend); 77 sendWindowUpdate(tosend); 78 } 79 } 80 } 81 } 82 sendWindowUpdate(int delta)83 void sendWindowUpdate(int delta) { 84 if (debug.on()) debug.log("sending window update: %d", delta); 85 connection.sendUnorderedFrame(new WindowUpdateFrame(getStreamId(), delta)); 86 } 87 88 volatile String dbgString; dbgString()89 String dbgString() { 90 String dbg = dbgString; 91 if (dbg != null) return dbg; 92 FlowTube tube = connection.connection.getConnectionFlow(); 93 if (tube == null) { 94 return "WindowUpdateSender(stream: " + getStreamId() + ")"; 95 } else { 96 int streamId = getStreamId(); 97 dbg = connection.dbgString() + ":WindowUpdateSender(stream: " + streamId + ")"; 98 return streamId == 0 ? dbg : (dbgString = dbg); 99 } 100 } 101 102 } 103