RFR: 8152423: Generated temp files (+JXF...temp) for custom fonts not deleted on exit.

[Jim Graham]

In that case, in order to avoid race conditions (GC could be 
accidentally triggered by this or subsequent shutdown hooks in the 
system), it should be released by calling disposer.dispose() instead of 
directly calling Release (still setting fontFace to null just in case). 
  That will ensure only one release per fontFace.

Also, in the constructor it looks like we'll construct a disposer for a 
null fontFace.  I don't think it hurts anything, and probably shouldn't 
happen in practice, but still seems odd...

		...jim

On 05/05/2016 11:40 AM, Phil Race wrote:
>
> On 05/05/2016 11:26 AM, Jim Graham wrote:
>> Is this true of any other objects managed by DWDisposer?
>
> DWDisposer is only the class used to implement "dispose()" of
> a  single DWFontFile that occurs during running/gc.
>
> It doesn't really "manage" anything and I don't see it used
> to dispose any other resource.
>
>> Would it be better to simply run through the DWDisposer queue on
>> shutdown and force it to dispose (i.e. release) everything it has?
>
> There isn't a "DWDisposer" queue - it is the shared disposer queue for
> all resources across Prism - so far as I can tell anyway.
>
> This clean up on exit of font files is initiated from a shutdown
> hook specific to the temporary font files (shared, not DW specific).
> To be able to delete the files we need to be sure that Release() was
> called before File.delete().
> So we either would need the font file shutdown hook to take ownership
> of first releasing other Prism resources as well or find a way to kick
> off a different
> hook specific to DWDisposer and ensure it runs before the deletion hook.
> I am not sure there is any way to guarantee that order.
>
> Also if we do an 8ux backport I'd want to do it this simpler way there
> even if something different were done for 9.
>
> -phil.
>
>>
>>             ...jim
>>
>> On 05/05/2016 11:12 AM, Phil Race wrote:
>>> Please review :-
>>> Bug : https://bugs.openjdk.java.net/browse/JDK-8152423
>>> Fix : http://cr.openjdk.java.net/~prr/8152423/
>>> <http://cr.openjdk.java.net/%7Eprr/8152423/>
>>>
>>> "Release" was not being called on the DirectWrite font object
>>> so it held a reference to the file, which on Windows prevents
>>> the file from being deleted.
>>>
>>> -phil
>