Re: Recent drawing optimizations

[David Ayers]

Ludovic Marcotte wrote:

> > However, for the GNUMail problems, this is only a workaround. GNUMail is
> > not supposed to make any of these calls in anything except the main
> > thread,
> >    
>
> It doesn't do any of these calls except in the main thread. The subthread 
> post distributed notifications when it wants to update the status label or 
> uses a NSConnection to the main thread to ask for passwords (prompting the 
> password panel), showing error (using alert panels) and stuff.
>
>  
>
> > so the root cause is that something is being run in the wrong
> > thread. I haven't looked closely at this, though, since I've been unable
> > to reproduce it. Ludovic?
> >    
>
> The stack trace Benhur posted shows where the crash is initiated. The 
> subthread in GNUMail post a distributed notification to update the status 
> label in the MailWindow. The MailWindowController adds itself as an 
> observer in the main thread for those distributed notifications 
> (GNUMailStatusLabelMessage). Upon reception of distributed notifications, 
> this will call, in the main thread, MailWindowController: 
> -updateStatusLabelWithMessage:.
>
> This used to work perfectly for months. I haven't changed anything lately 
> related to that.
>  
Here's my quick shot at this:

I believe the distributed notification center probably doesn't know 
anything about threads.  Any thread running a runloop can probably 
receive and process distributed notifications.  In a mutli threaded App 
it would be the responsiblity of the method invoked by notification 
center to make sure it runs in the correct thread by forwarding it to a 
proxy for the intended thread, if it doesn't happen to be that thread 
itself.

Cheers,
Dave