| /* |
| * Copyright (c) 1998, 2006, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.tools.jdi; |
| |
| import com.sun.jdi.*; |
| import com.sun.jdi.event.EventQueue; |
| import com.sun.jdi.event.EventSet; |
| |
| import java.util.*; |
| |
| public class EventQueueImpl extends MirrorImpl implements EventQueue { |
| |
| /* |
| * Note this is not a synchronized list. Iteration/update should be |
| * protected through the 'this' monitor. |
| */ |
| LinkedList<EventSet> eventSets = new LinkedList<EventSet>(); |
| |
| TargetVM target; |
| boolean closed = false; |
| |
| EventQueueImpl(VirtualMachine vm, TargetVM target) { |
| super(vm); |
| this.target = target; |
| target.addEventQueue(this); |
| } |
| |
| /* |
| * Override superclass back to default equality |
| */ |
| public boolean equals(Object obj) { |
| return this == obj; |
| } |
| |
| public int hashCode() { |
| return System.identityHashCode(this); |
| } |
| |
| synchronized void enqueue(EventSet eventSet) { |
| eventSets.add(eventSet); |
| notifyAll(); |
| } |
| |
| synchronized int size() { |
| return eventSets.size(); |
| } |
| |
| synchronized void close() { |
| if (!closed) { |
| closed = true; // OK for this the be first since synchronized |
| |
| // place VMDisconnectEvent into queue |
| enqueue(new EventSetImpl(vm, |
| (byte)JDWP.EventKind.VM_DISCONNECTED)); |
| } |
| } |
| |
| public EventSet remove() throws InterruptedException { |
| return remove(0); |
| } |
| |
| /** |
| * Filter out events not for user's eyes. |
| * Then filter out empty sets. |
| */ |
| public EventSet remove(long timeout) throws InterruptedException { |
| if (timeout < 0) { |
| throw new IllegalArgumentException("Timeout cannot be negative"); |
| } |
| |
| EventSet eventSet; |
| while (true) { |
| EventSetImpl fullEventSet = removeUnfiltered(timeout); |
| if (fullEventSet == null) { |
| eventSet = null; // timeout |
| break; |
| } |
| /* |
| * Remove events from the event set for which |
| * there is no corresponding enabled request ( |
| * this includes our internally requested events.) |
| * This never returns null |
| */ |
| eventSet = fullEventSet.userFilter(); |
| if (!eventSet.isEmpty()) { |
| break; |
| } |
| } |
| |
| if ((eventSet != null) && (eventSet.suspendPolicy() == JDWP.SuspendPolicy.ALL)) { |
| vm.notifySuspend(); |
| } |
| |
| return eventSet; |
| } |
| |
| EventSet removeInternal() throws InterruptedException { |
| EventSet eventSet; |
| do { |
| // Waiting forever, so removeUnfiltered() is never null |
| eventSet = removeUnfiltered(0).internalFilter(); |
| } while (eventSet == null || eventSet.isEmpty()); |
| |
| /* |
| * Currently, no internal events are requested with a suspend |
| * policy other than none, so we don't check for notifySuspend() |
| * here. If this changes in the future, there is much |
| * infrastructure that needs to be updated. |
| */ |
| |
| return eventSet; |
| } |
| |
| private TimerThread startTimerThread(long timeout) { |
| TimerThread thread = new TimerThread(timeout); |
| thread.setDaemon(true); |
| thread.start(); |
| return thread; |
| } |
| |
| private boolean shouldWait(TimerThread timerThread) { |
| return !closed && eventSets.isEmpty() && |
| ((timerThread == null) ? true : !timerThread.timedOut()); |
| } |
| |
| private EventSetImpl removeUnfiltered(long timeout) |
| throws InterruptedException { |
| EventSetImpl eventSet = null; |
| |
| /* |
| * Make sure the VM has completed initialization before |
| * trying to build events. |
| */ |
| vm.waitInitCompletion(); |
| |
| synchronized(this) { |
| if (!eventSets.isEmpty()) { |
| /* |
| * If there's already something there, no need |
| * for anything elaborate. |
| */ |
| eventSet = (EventSetImpl)eventSets.removeFirst(); |
| } else { |
| /* |
| * If a timeout was specified, create a thread to |
| * notify this one when a timeout |
| * occurs. We can't use the timed version of wait() |
| * because it is possible for multiple enqueue() calls |
| * before we see something in the eventSet queue |
| * (this is possible when multiple threads call |
| * remove() concurrently -- not a great idea, but |
| * it should be supported). Even if enqueue() did a |
| * notify() instead of notifyAll() we are not able to |
| * use a timed wait because there's no way to distinguish |
| * a timeout from a notify. That limitation implies a |
| * possible race condition between a timed out thread |
| * and a notified thread. |
| */ |
| TimerThread timerThread = null; |
| try { |
| if (timeout > 0) { |
| timerThread = startTimerThread(timeout); |
| } |
| |
| while (shouldWait(timerThread)) { |
| this.wait(); |
| } |
| } finally { |
| if ((timerThread != null) && !timerThread.timedOut()) { |
| timerThread.interrupt(); |
| } |
| } |
| |
| if (eventSets.isEmpty()) { |
| if (closed) { |
| throw new VMDisconnectedException(); |
| } |
| } else { |
| eventSet = (EventSetImpl)eventSets.removeFirst(); |
| } |
| } |
| } |
| |
| // The build is synchronized on the event set, don't hold |
| // the queue lock. |
| if (eventSet != null) { |
| target.notifyDequeueEventSet(); |
| eventSet.build(); |
| } |
| return eventSet; |
| } |
| |
| private class TimerThread extends Thread { |
| private boolean timedOut = false; |
| private long timeout; |
| |
| TimerThread(long timeout) { |
| super(vm.threadGroupForJDI(), "JDI Event Queue Timer"); |
| this.timeout = timeout; |
| } |
| |
| boolean timedOut() { |
| return timedOut; |
| } |
| |
| public void run() { |
| try { |
| Thread.sleep(timeout); |
| EventQueueImpl queue = EventQueueImpl.this; |
| synchronized(queue) { |
| timedOut = true; |
| queue.notifyAll(); |
| } |
| } catch (InterruptedException e) { |
| // Exit without notifying |
| } |
| } |
| } |
| } |