[OpenJDK 2D-Dev] [9] Review request for 8130136: Swing window sometimes fails to repaint partially when it becomes exposed

[Alexey Ivanov]

Hello,

Please review the fix for jdk9:
     bug: https://bugs.openjdk.java.net/browse/JDK-8130136
     webrev: http://cr.openjdk.java.net/~aivanov/8130136/jdk9/webrev.00/


Problem description:
Sometimes a window fails to repaint when it becomes exposed.

When repaint failure occurs, SetDIBitsToDevice() in 
GDIBlitLoops_nativeBlit() returns 0 with error 87 ("Parameter Error"). 
It happens because invalid, already released, hDC is passed to 
SetDIBitsToDevice().


Root cause:
When a window is disposed, the DCs associated with it are released. The 
handles can be reused for another window.

A thread disposes the window and releases hDC. At this time, DC handle 
is reused for another window. When Disposer thread cleans up for a died 
thread, it tries to release the cached hDC. But that handle is already 
associated with another window. Thus a valid pair hWnd/hDC becomes 
invalid: painting to released DC fails.


The fix:
Save both hDC and hWnd in the thread local storage, and pair hDC with 
hWnd when removing it to avoid accidentally releasing hDC which is 
already reused for another window.


Regards,
Alexey