Hi Sergey,
In XAWT, we usually use the StateLock to synchronize access to peer
fields (such as background, label, etc.) I don't think that switching to
volatile is a good idea since it prevents us from performing atomic
read/writes to the fields. And this is exactly what we need for this
fix, actually. In other words, the following pattern works perfectly:
synchronized (lock) {
if (a != b) {
a = b;
// do stuff, or set a flag to do it later w/o the lock
}
}
whereas the following doesn't:
volatile a;
if (a != b) {
a = b;
// do stuff
}
The latter doesn't work because the value of 'a' may change from another
thread after the if() statement in the first thread is executed.
Please note that this is critical for AWT because it is a multi-threaded
GUI toolkit.
src/solaris/classes/sun/awt/X11/XListPeer.java
- target.paint(g);
+ handleExposeEvent(target, 0, 0, getWidth(), getHeight());
(the same applies to XWindow.repaint): can you please rename
XWindow.handleExposeEvent(Component...) to postPaintEvent() and make it
final? A good javadoc for this method would also be appreciated, because
currently seeing the name handle*() I'd think it needs to be done under
the awtLock().
Also, for the corresponding changes in XWindow.repaint(), could you
please elaborate a bit more? Looking at the code I see that
XWindow.paint() calls paintPeer(). And in repaint(), you either call
paint() or paintPeer() depending on the current thread. Why is it
needed? Can we just call paintPeer() (or paint() for that matter)
unconditionally since they both seem to result in the same call? Also,
why don't we post an event if reapint() is invoked on the EDT?
--
best regards,
Anthony
On 10/16/2013 06:00 PM, Sergey Bylokhov wrote:
Hello.
Please review the fix for jdk 8.
The fix has two parts
- Repaint method in the peer now paint the component in place if it
was called on EDT only.
- Most of setters were changed to stop recursion if they were called
on EDT.
Bug: https://bugs.openjdk.java.net/browse/JDK-7090424
Webrev can be found at: http://cr.openjdk.java.net/~serb/7090424/webrev.00
