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| 1 | /* | ||
| 2 | * Copyright (c) 1998, 2006, 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 com.sun.tools.jdi; | ||
| 27 | |||
| 28 | import com.sun.jdi.*; | ||
| 29 | import com.sun.jdi.event.EventQueue; | ||
| 30 | import com.sun.jdi.event.EventSet; | ||
| 31 | |||
| 32 | import java.util.*; | ||
| 33 | |||
| 34 | public class EventQueueImpl extends MirrorImpl implements EventQueue { | ||
| 35 | |||
| 36 | /* | ||
| 37 | * Note this is not a synchronized list. Iteration/update should be | ||
| 38 | * protected through the 'this' monitor. | ||
| 39 | */ | ||
| 40 | LinkedList<EventSet> eventSets = new LinkedList<EventSet>(); | ||
| 41 | |||
| 42 | TargetVM target; | ||
| 43 | boolean closed = false; | ||
| 44 | |||
| 45 | EventQueueImpl(VirtualMachine vm, TargetVM target) { | ||
| 46 | super(vm); | ||
| 47 | this.target = target; | ||
| 48 | target.addEventQueue(this); | ||
| 49 | } | ||
| 50 | |||
| 51 | /* | ||
| 52 | * Override superclass back to default equality | ||
| 53 | */ | ||
| 54 | public boolean equals(Object obj) { | ||
| 55 | return this == obj; | ||
| 56 | } | ||
| 57 | |||
| 58 | public int hashCode() { | ||
| 59 | return System.identityHashCode(this); | ||
| 60 | } | ||
| 61 | |||
| 62 | synchronized void enqueue(EventSet eventSet) { | ||
| 63 | eventSets.add(eventSet); | ||
| 64 | notifyAll(); | ||
| 65 | } | ||
| 66 | |||
| 67 | synchronized int size() { | ||
| 68 | return eventSets.size(); | ||
| 69 | } | ||
| 70 | |||
| 71 | synchronized void close() { | ||
| 72 | if (!closed) { | ||
| 73 | closed = true; // OK for this the be first since synchronized | ||
| 74 | |||
| 75 | // place VMDisconnectEvent into queue | ||
| 76 | enqueue(new EventSetImpl(vm, | ||
| 77 | (byte)JDWP.EventKind.VM_DISCONNECTED)); | ||
| 78 | } | ||
| 79 | } | ||
| 80 | |||
| 81 | public EventSet remove() throws InterruptedException { | ||
| 82 | return remove(0); | ||
| 83 | } | ||
| 84 | |||
| 85 | /** | ||
| 86 | * Filter out events not for user's eyes. | ||
| 87 | * Then filter out empty sets. | ||
| 88 | */ | ||
| 89 | public EventSet remove(long timeout) throws InterruptedException { | ||
| 90 | if (timeout < 0) { | ||
| 91 | throw new IllegalArgumentException("Timeout cannot be negative"); | ||
| 92 | } | ||
| 93 | |||
| 94 | EventSet eventSet; | ||
| 95 | while (true) { | ||
| 96 | EventSetImpl fullEventSet = removeUnfiltered(timeout); | ||
| 97 | if (fullEventSet == null) { | ||
| 98 | eventSet = null; // timeout | ||
| 99 | break; | ||
| 100 | } | ||
| 101 | /* | ||
| 102 | * Remove events from the event set for which | ||
| 103 | * there is no corresponding enabled request ( | ||
| 104 | * this includes our internally requested events.) | ||
| 105 | * This never returns null | ||
| 106 | */ | ||
| 107 | eventSet = fullEventSet.userFilter(); | ||
| 108 | if (!eventSet.isEmpty()) { | ||
| 109 | break; | ||
| 110 | } | ||
| 111 | } | ||
| 112 | |||
| 113 | if ((eventSet != null) && (eventSet.suspendPolicy() == JDWP.SuspendPolicy.ALL)) { | ||
| 114 | vm.notifySuspend(); | ||
| 115 | } | ||
| 116 | |||
| 117 | return eventSet; | ||
| 118 | } | ||
| 119 | |||
| 120 | EventSet removeInternal() throws InterruptedException { | ||
| 121 | EventSet eventSet; | ||
| 122 | do { | ||
| 123 | // Waiting forever, so removeUnfiltered() is never null | ||
| 124 | eventSet = removeUnfiltered(0).internalFilter(); | ||
| 125 | } while (eventSet == null || eventSet.isEmpty()); | ||
| 126 | |||
| 127 | /* | ||
| 128 | * Currently, no internal events are requested with a suspend | ||
| 129 | * policy other than none, so we don't check for notifySuspend() | ||
| 130 | * here. If this changes in the future, there is much | ||
| 131 | * infrastructure that needs to be updated. | ||
| 132 | */ | ||
| 133 | |||
| 134 | return eventSet; | ||
| 135 | } | ||
| 136 | |||
| 137 | private TimerThread startTimerThread(long timeout) { | ||
| 138 | TimerThread thread = new TimerThread(timeout); | ||
| 139 | thread.setDaemon(true); | ||
| 140 | thread.start(); | ||
| 141 | return thread; | ||
| 142 | } | ||
| 143 | |||
| 144 | private boolean shouldWait(TimerThread timerThread) { | ||
| 145 | return !closed && eventSets.isEmpty() && | ||
| 146 | ((timerThread == null) ? true : !timerThread.timedOut()); | ||
| 147 | } | ||
| 148 | |||
| 149 | private EventSetImpl removeUnfiltered(long timeout) | ||
| 150 | throws InterruptedException { | ||
| 151 | EventSetImpl eventSet = null; | ||
| 152 | |||
| 153 | /* | ||
| 154 | * Make sure the VM has completed initialization before | ||
| 155 | * trying to build events. | ||
| 156 | */ | ||
| 157 | vm.waitInitCompletion(); | ||
| 158 | |||
| 159 | synchronized(this) { | ||
| 160 | if (!eventSets.isEmpty()) { | ||
| 161 | /* | ||
| 162 | * If there's already something there, no need | ||
| 163 | * for anything elaborate. | ||
| 164 | */ | ||
| 165 | eventSet = (EventSetImpl)eventSets.removeFirst(); | ||
| 166 | } else { | ||
| 167 | /* | ||
| 168 | * If a timeout was specified, create a thread to | ||
| 169 | * notify this one when a timeout | ||
| 170 | * occurs. We can't use the timed version of wait() | ||
| 171 | * because it is possible for multiple enqueue() calls | ||
| 172 | * before we see something in the eventSet queue | ||
| 173 | * (this is possible when multiple threads call | ||
| 174 | * remove() concurrently -- not a great idea, but | ||
| 175 | * it should be supported). Even if enqueue() did a | ||
| 176 | * notify() instead of notifyAll() we are not able to | ||
| 177 | * use a timed wait because there's no way to distinguish | ||
| 178 | * a timeout from a notify. That limitation implies a | ||
| 179 | * possible race condition between a timed out thread | ||
| 180 | * and a notified thread. | ||
| 181 | */ | ||
| 182 | TimerThread timerThread = null; | ||
| 183 | try { | ||
| 184 | if (timeout > 0) { | ||
| 185 | timerThread = startTimerThread(timeout); | ||
| 186 | } | ||
| 187 | |||
| 188 | while (shouldWait(timerThread)) { | ||
| 189 | this.wait(); | ||
| 190 | } | ||
| 191 | } finally { | ||
| 192 | if ((timerThread != null) && !timerThread.timedOut()) { | ||
| 193 | timerThread.interrupt(); | ||
| 194 | } | ||
| 195 | } | ||
| 196 | |||
| 197 | if (eventSets.isEmpty()) { | ||
| 198 | if (closed) { | ||
| 199 | throw new VMDisconnectedException(); | ||
| 200 | } | ||
| 201 | } else { | ||
| 202 | eventSet = (EventSetImpl)eventSets.removeFirst(); | ||
| 203 | } | ||
| 204 | } | ||
| 205 | } | ||
| 206 | |||
| 207 | // The build is synchronized on the event set, don't hold | ||
| 208 | // the queue lock. | ||
| 209 | if (eventSet != null) { | ||
| 210 | target.notifyDequeueEventSet(); | ||
| 211 | eventSet.build(); | ||
| 212 | } | ||
| 213 | return eventSet; | ||
| 214 | } | ||
| 215 | |||
| 216 | private class TimerThread extends Thread { | ||
| 217 | private boolean timedOut = false; | ||
| 218 | private long timeout; | ||
| 219 | |||
| 220 | TimerThread(long timeout) { | ||
| 221 | super(vm.threadGroupForJDI(), "JDI Event Queue Timer"); | ||
| 222 | this.timeout = timeout; | ||
| 223 | } | ||
| 224 | |||
| 225 | boolean timedOut() { | ||
| 226 | return timedOut; | ||
| 227 | } | ||
| 228 | |||
| 229 | public void run() { | ||
| 230 | try { | ||
| 231 | Thread.sleep(timeout); | ||
| 232 | EventQueueImpl queue = EventQueueImpl.this; | ||
| 233 | synchronized(queue) { | ||
| 234 | timedOut = true; | ||
| 235 | queue.notifyAll(); | ||
| 236 | } | ||
| 237 | } catch (InterruptedException e) { | ||
| 238 | // Exit without notifying | ||
| 239 | } | ||
| 240 | } | ||
| 241 | } | ||
| 242 | } | ||