<AWT Dev> Code Review Request for CR 7128738 - dragged dialog freezes system on dispose

[Oleg Pekhovskiy]

Hi Anthony,

thanks you for your proposal!

Freezing behavior occurs only until JVM finishes, when all other java 
objects are disposed.
In example provided in CR's evaluation field the primary frame prevents 
JVM from finishing, that causes freezing.

So, the test, I propose, disposes the primary frame, that eliminates 
freezing:
http://cr.openjdk.java.net/~bagiras/8/7128738.2

Thanks,
Oleg

3/14/2012 6:16 AM, Anthony Petrov wrote:
> Hi Oleg,
>
> The fix looks good to me. It would be cool to write a regression test 
> for the issue, btw. You could start dragging a frame using Robot, and 
> then call dispose() a couple seconds before releasing a mouse button. 
> The test would fail by time-out w/o the fix.
>
> -- 
> best regards,
> Anthony
>
> On 3/14/2012 1:54 AM, Oleg Pekhovskiy wrote:
>> Hi guys,
>>
>> please review the fix for:
>> http://bugs.sun.com/view_bug.do?bug_id=7128738
>>
>> webrev:
>> http://cr.openjdk.java.net/~bagiras/7128738.1
>>
>> Description:
>>
>> Entering 'move window' mode clicking window title bar sends 
>> WM_SYSCOMMAND with SC_MOVE inside WM_NCLBUTTONDOWN.
>> As a result additional message pump (for mouse capture) is created 
>> blocking the handlers' chain WM_NCLBUTTONDOWN -> WM_SYSCOMMAND.
>>
>> So when JFrame.dispose() is called during this situation, deleting of 
>> native AwtFrame object could NOT be done because 
>> AwtComponent::CanBeDeleted() returns FALSE
>> (because of WM_NCLBUTTONDOWN & WM_SYSCOMMAND) and WM_AWT_DELETEOBJECT 
>> message is reposted over and over again (eating CPU time).
>>
>> Thus I added ReleaseDragCapture(0) to AwtComponent::Dispose() to 
>> release mouse capture and finish the additional message pump
>> so that AwtComponent::CanBeDeleted() returns TRUE and AwtFrame object 
>> is deleted.
>>
>> Thanks,
>> Oleg