Re: MY window tree!

["Lennart Borgman (gmail)" <lennart.borgman@gmail.com>]

martin rudalics wrote:

Hi Martin, thanks for answering so that we can clear this out. But I 
still think we are misunderstanding each other a little bit. Please see 
if my answers below.


>  > 1) I think I must search all buffers
> 
> No.  Only the buffers that have an ovlwin-window association.


There is unfortunately no way to find out if a buffer have that without 
looking at the overlays in the buffer AFAICS.


>  > 2) I must check all overlays in these buffers
> 
> Yes (unfortunately) but _only_ in the buffers mentioned above.
> 
>  > 3) The only thing I have to check in the overlays is the 'window prop
> 
> Yes.
> 
>  > 4) I only have to care if the prop value is a window in the saved tree
> 
> Yes.
> 
>  > 5) If that window is not on a frame any more I just replace the value
> 
> Together steps 1) and 4) assert that the window is not on a frame any
> more, hence, you don't have to check this.


If you are thinking of the normal use case (which is adding a BAR 
window, see winsav.el) you are right, but there may be other ways to use 
this too. In those cases the old windows may still be there on the old 
frame. (The user of these functions may for some reason be copying the 
window structure somewhere else. Do not ask me why, but the possibility 
to do that is there.)


>  > 6) Otherwise I make a new overlay -- seldom
> 
> _Never_ make a new overlay.


Yes, never in the normal use case.


>  > The above is what I am doing. Is any of those points incorrect in your
>  > opinion? Here is the code:
>  >
>  >     (dolist (buf (buffer-list))
> 
> `buffer-list' is bad.  I'd use something like
> 
> (dolist (buf (let (buffer buffers)
>            (dolist (win win-list buffers)
>              ;; I presume cadr refers to the "new" window.
>          (setq buffer (window-buffer (cadr win)))
>          (unless (memq buffer buffers)
>            (setq buffers (cons buffer buffers))))))
>   ...


Why should I only investigate those buffers?


> If the old window is still alive don't do anything.  Windows that
> survived the reconfiguration should not be on `win-list'.


In the normal use case what you are saying is correct, but there may be 
other cases.


>  > I believe it would be possible to right code to manipulate the internal
>  > tree as above. A solution building on that would probably use the
>  > resizing part from my elisp solution (or something similar).
> 
> The only time and space consuming operation is finding the overlays and
> changing their property.  There's nothing you can do about that.  Note
> that current solutions (like `edebug-current-windows') ignore overlays
> (and many other things like dedicated windows) completely.  This could
> be corrected with your algorithm, provided the save/restore step occurs
> smoothly.


If so that would be good of course.


> For `desktop-save', on the other hand, you should think of an option to
> ignore overlays, though.  Storing overlays on disk is hardly conceivable
> as long as we don't even bother to save text properties.


Yes, thanks, I have thought of that and just asked the maintainer of 
desktop.el if he is interested.