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EventQueue.java (pop): Prevent racing condition to add events to the queue out of order by acquiring...

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* java/awt/EventQueue.java (pop): Prevent racing condition to add
        events to the queue out of order by acquiring locks in the proper
        order and not by releasing one before acquiring the other.

From-SVN: r76161
This commit is contained in:
Fernando Nasser 2004-01-19 17:38:36 +00:00 • committed by Fernando Nasser
parent 8f9f8d71c7
commit 605d10f7f2
2 changed files with 26 additions and 18 deletions
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6
libjava/ChangeLog
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@ -1,3 +1,9 @@
2004-01-19 Fernando Nasser <fnasser@redhat.com>
* java/awt/EventQueue.java (pop): Prevent racing condition to add
events to the queue out of order by acquiring locks in the proper
order and not by releasing one before acquiring the other.
2004-01-19 Fernando Nasser <fnasser@redhat.com>
* gnu/java/awt/peer/gtk/TestAWT.java (DialogWindow): Make text not

38
libjava/java/awt/EventQueue.java
View file

@ -358,32 +358,34 @@ public class EventQueue
if (prev == null)
throw new EmptyStackException();
// Don't synchronize both this and prev at the same time, or deadlock could
// occur.
/* The order is important here, we must get the prev lock first,
or deadlock could occur as callers usually get here following
prev's next pointer, and thus obtain prev's lock before trying
to get this lock. */
synchronized (prev)
{
prev.next = next;
if (next != null)
next.prev = prev;
}
synchronized (this)
{
int i = next_out;
while (i != next_in)
synchronized (this)
{
prev.postEvent(queue[i]);
next_out = i;
if (++i == queue.length)
i = 0;
}
// Empty the queue so it can be reused
next_in = 0;
next_out = 0;
int i = next_out;
while (i != next_in)
{
prev.postEvent(queue[i]);
next_out = i;
if (++i == queue.length)
i = 0;
}
// Empty the queue so it can be reused
next_in = 0;
next_out = 0;
// Tell our EventDispatchThread that it can end execution
dispatchThread.interrupt ();
dispatchThread = null;
// Tell our EventDispatchThread that it can end execution
dispatchThread.interrupt ();
dispatchThread = null;
}
}
}