Re: NSMenuView patch

[Wolfgang Lux]

Hi Fred!

> First off, we are talking about a method here that is already 350  
> lines
> long. This surely is wrong and needs to be changed. The patch only
> slightly shortens the method, but makes a few things clearer, which
> surly is a good thing.
> Christopher also took create care to release the captured mouse on all
> possible paths. This is very important, as otherwise the application
> could stop responding. But now consider that somebody else works on  
> this
> method in the future. The person might easily not know about that
> necessity and accidentally break stuff. Even in this patch the mouse
> sometimes gets release after a tracking in a submenu. I don't have a
> clue how this is supposed to work. We always have to release the mouse
> before handling over control to a different window. This of course is
> easy to fix for now. But who will remember this for future changes?
>
> As much as I like the idea of this patch, I think it is too fragile  
> code
> to be added. We should think hard on how to restructure the code  
> here to
> make it less fragile and then we might be able to safely add a mouse
> capture to it.

The safe solution is of course to move the body of this method without  
the code for capturing the mouse into a new private method - 
_trackWithEvent: and to define trackWithEvent: as a thin wrapper  
around the new method, which performs mouse capturing. E.g., something  
like

  - (BOOL)trackWithEvent:(NSEvent *)event
  {
    BOOL result;

    [_window _captureMouse: self];
    NS_DURING
      result = [self _trackWithEvent: self];
    NS_HANDLER
      [_window _releaseMouse: self];
      [localException raise];
    NS_ENDHANDLER
    [_window _releaseMouse: self];
    return result;
  }

Just my 0.02€
Wolfgang