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7186109: Simplify lock machinery for PostEventQueue & EventQueue

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Reviewed-by: art, anthony, dholmes
This commit is contained in:
Oleg Pekhovskiy 2012-09-13 19:53:13 +04:00
parent 589854449e
commit 08a51f1378
4 changed files with 148 additions and 48 deletions
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4
jdk/src/macosx/classes/sun/lwawt/macosx/LWCToolkit.java
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@ -536,7 +536,7 @@ public class LWCToolkit extends LWToolkit {
SunToolkit.postEvent(appContext, invocationEvent);
// 3746956 - flush events from PostEventQueue to prevent them from getting stuck and causing a deadlock
sun.awt.SunToolkitSubclass.flushPendingEvents(appContext);
SunToolkit.flushPendingEvents(appContext);
} else {
// This should be the equivalent to EventQueue.invokeAndWait
((LWCToolkit)Toolkit.getDefaultToolkit()).getSystemEventQueueForInvokeAndWait().postEvent(invocationEvent);
@ -561,7 +561,7 @@ public class LWCToolkit extends LWToolkit {
SunToolkit.postEvent(appContext, invocationEvent);
// 3746956 - flush events from PostEventQueue to prevent them from getting stuck and causing a deadlock
sun.awt.SunToolkitSubclass.flushPendingEvents(appContext);
SunToolkit.flushPendingEvents(appContext);
} else {
// This should be the equivalent to EventQueue.invokeAndWait
((LWCToolkit)Toolkit.getDefaultToolkit()).getSystemEventQueueForInvokeAndWait().postEvent(invocationEvent);

9
jdk/src/share/classes/java/awt/EventQueue.java
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@ -1046,6 +1046,10 @@ public class EventQueue {
}
final boolean detachDispatchThread(EventDispatchThread edt, boolean forceDetach) {
/*
* Minimize discard possibility for non-posted events
*/
SunToolkit.flushPendingEvents();
/*
* This synchronized block is to secure that the event dispatch
* thread won't die in the middle of posting a new event to the
@ -1060,11 +1064,8 @@ public class EventQueue {
/*
* Don't detach the thread if any events are pending. Not
* sure if it's a possible scenario, though.
*
* Fix for 4648733. Check both the associated java event
* queue and the PostEventQueue.
*/
if (!forceDetach && (peekEvent() != null) || !SunToolkit.isPostEventQueueEmpty()) {
if (!forceDetach && (peekEvent() != null)) {
return false;
}
dispatchThread = null;

92
jdk/src/share/classes/sun/awt/SunToolkit.java
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@ -506,40 +506,25 @@ public abstract class SunToolkit extends Toolkit
postEvent(targetToAppContext(e.getSource()), pe);
}
protected static final Lock flushLock = new ReentrantLock();
private static boolean isFlushingPendingEvents = false;
/*
* Flush any pending events which haven't been posted to the AWT
* EventQueue yet.
*/
public static void flushPendingEvents() {
flushLock.lock();
try {
// Don't call flushPendingEvents() recursively
if (!isFlushingPendingEvents) {
isFlushingPendingEvents = true;
AppContext appContext = AppContext.getAppContext();
PostEventQueue postEventQueue =
(PostEventQueue)appContext.get(POST_EVENT_QUEUE_KEY);
if (postEventQueue != null) {
postEventQueue.flush();
}
}
} finally {
isFlushingPendingEvents = false;
flushLock.unlock();
}
AppContext appContext = AppContext.getAppContext();
flushPendingEvents(appContext);
}
public static boolean isPostEventQueueEmpty() {
AppContext appContext = AppContext.getAppContext();
/*
* Flush the PostEventQueue for the right AppContext.
* The default flushPendingEvents only flushes the thread-local context,
* which is not always correct, c.f. 3746956
*/
public static void flushPendingEvents(AppContext appContext) {
PostEventQueue postEventQueue =
(PostEventQueue)appContext.get(POST_EVENT_QUEUE_KEY);
(PostEventQueue)appContext.get(POST_EVENT_QUEUE_KEY);
if (postEventQueue != null) {
return postEventQueue.noEvents();
} else {
return true;
postEventQueue.flush();
}
}
@ -2045,17 +2030,12 @@ class PostEventQueue {
private EventQueueItem queueTail = null;
private final EventQueue eventQueue;
// For the case when queue is cleared but events are not posted
private volatile boolean isFlushing = false;
private Thread flushThread = null;
PostEventQueue(EventQueue eq) {
eventQueue = eq;
}
public synchronized boolean noEvents() {
return queueHead == null && !isFlushing;
}
/*
* Continually post pending AWTEvents to the Java EventQueue. The method
* is synchronized to ensure the flush is completed before a new event
@ -2066,20 +2046,48 @@ class PostEventQueue {
* potentially lead to deadlock
*/
public void flush() {
EventQueueItem tempQueue;
synchronized (this) {
tempQueue = queueHead;
queueHead = queueTail = null;
isFlushing = true;
}
Thread newThread = Thread.currentThread();
try {
while (tempQueue != null) {
eventQueue.postEvent(tempQueue.event);
tempQueue = tempQueue.next;
EventQueueItem tempQueue;
synchronized (this) {
// Avoid method recursion
if (newThread == flushThread) {
return;
}
// Wait for other threads' flushing
while (flushThread != null) {
wait();
}
// Skip everything if queue is empty
if (queueHead == null) {
return;
}
// Remember flushing thread
flushThread = newThread;
tempQueue = queueHead;
queueHead = queueTail = null;
}
try {
while (tempQueue != null) {
eventQueue.postEvent(tempQueue.event);
tempQueue = tempQueue.next;
}
}
finally {
// Only the flushing thread can get here
synchronized (this) {
// Forget flushing thread, inform other pending threads
flushThread = null;
notifyAll();
}
}
}
finally {
isFlushing = false;
catch (InterruptedException e) {
// Couldn't allow exception go up, so at least recover the flag
newThread.interrupt();
}
}

91
jdk/test/java/awt/EventQueue/PostEventOrderingTest/PostEventOrderingTest.java Normal file
View File

@ -0,0 +1,91 @@
/*
* Copyright (c) 2012, 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.
*/
/**
* @test PostEventOrderingTest.java
* @bug 4171596 6699589
* @summary Checks that the posting of events between the PostEventQueue
* @summary and the EventQueue maintains proper ordering.
* @run main PostEventOrderingTest
* @author fredx
*/
import java.awt.*;
import java.awt.event.*;
import sun.awt.AppContext;
import sun.awt.SunToolkit;
public class PostEventOrderingTest {
static boolean testPassed = true;
public static void main(String[] args) throws Throwable {
EventQueue q = Toolkit.getDefaultToolkit().getSystemEventQueue();
for (int i = 0; i < 100; i++) {
for (int j = 0; j < 100; j++) {
q.postEvent(new PostActionEvent());
for (int k = 0; k < 10; k++) {
SunToolkit.postEvent(AppContext.getAppContext(), new PostActionEvent());
}
}
for (int k = 0; k < 100; k++) {
SunToolkit.postEvent(AppContext.getAppContext(), new PostActionEvent());
}
}
for (;;) {
Thread.currentThread().sleep(100);
if (q.peekEvent() == null) {
Thread.currentThread().sleep(100);
if (q.peekEvent() == null)
break;
}
}
if (!testPassed) {
throw new Exception("PostEventOrderingTest FAILED -- events dispatched out of order.");
} else {
System.out.println("PostEventOrderingTest passed!");
}
}
}
class PostActionEvent extends ActionEvent implements ActiveEvent {
static int counter = 0;
static int mostRecent = -1;
int myval;
public PostActionEvent() {
super("", ACTION_PERFORMED, "" + counter);
myval = counter++;
}
public void dispatch() {
//System.out.println("myval = "+myval+", mostRecent = "+mostRecent+", diff = "+(myval-mostRecent)+".");
if ((myval - mostRecent) != 1)
PostEventOrderingTest.testPassed = false;
mostRecent = myval;
}
}