Strange code in nsterm.m

Strange code in nsterm.m

[Eli Zaretskii]

Here's mouseExited from nsterm.m:

  - (void)mouseExited: (NSEvent *)theEvent
  {
    NSPoint p = [self convertPoint: [theEvent locationInWindow] fromView: nil];
    NSRect r;
    struct ns_display_info *dpyinfo
      = emacsframe ? FRAME_NS_DISPLAY_INFO (emacsframe) : NULL;

    NSTRACE (mouseExited);

    if (dpyinfo || !emacsframe)  <<<<<<<<<<<<<<<<<<<<<<<
      return;

    last_mouse_movement_time = EV_TIMESTAMP (theEvent);

    if (emacsframe == dpyinfo->mouse_face_mouse_frame)
      {
	clear_mouse_face (dpyinfo);
	dpyinfo->mouse_face_mouse_frame = 0;
      }
  }

Isn't the line marked with <<<<<<<<<<<<<<<<<<<<<<< wrong?  It should
say

    if (!dpyinfo || !emacsframe)
      return;

right?  Because if dpyinfo is NULL, we cannot dereference it two lines
after that.  Am I missing something?

Re: Strange code in nsterm.m

[Jan Djärv]

Eli Zaretskii skrev 2010-11-01 21.08:
> Here's mouseExited from nsterm.m:
>
>    - (void)mouseExited: (NSEvent *)theEvent
>    {
>      NSPoint p = [self convertPoint: [theEvent locationInWindow] fromView: nil];
>      NSRect r;
>      struct ns_display_info *dpyinfo
>        = emacsframe ? FRAME_NS_DISPLAY_INFO (emacsframe) : NULL;
>
>      NSTRACE (mouseExited);
>
>      if (dpyinfo || !emacsframe)<<<<<<<<<<<<<<<<<<<<<<<
>        return;
>
>      last_mouse_movement_time = EV_TIMESTAMP (theEvent);
>
>      if (emacsframe == dpyinfo->mouse_face_mouse_frame)
>        {
> 	clear_mouse_face (dpyinfo);
> 	dpyinfo->mouse_face_mouse_frame = 0;
>        }
>    }
>
> Isn't the line marked with<<<<<<<<<<<<<<<<<<<<<<<  wrong?  It should
> say
>
>      if (!dpyinfo || !emacsframe)
>        return;
>
> right?  Because if dpyinfo is NULL, we cannot dereference it two lines
> after that.  Am I missing something?

No your analysis is correct.  However, mouseExited doesn't seem to get called 
on OSX.  Not sure if the mouse face gets cleared someplace else.  Initial 
testing indicates that it does, probably when loosing focus.

	Jan D.