Suggested patch for desktop.el, and 'slothful' lazy file loading

Suggested patch for desktop.el, and 'slothful' lazy file loading

[Paul Sexton]

Apologies if this is the wrong place to send a message like this. I 
originally sent it the email address of the maintainer of desktop.el,
terra@diku.dk, but that address is dead.

I have been using desktop.el in "lazy" mode i.e. with the settings

(setq desktop-restore-eager 10)
(setq desktop-lazy-verbose nil)

This is supposed to make it load the first 10 files normally, then load the 
rest "in the background" when Emacs is idle.

I have found that although the extra buffers are loaded in the
background, after each buffer is loaded the display still switches to
that buffer. This is very disconcerting - you are trying to work in 
buffer A but you are constantly switched against your will to
viewing buffer B, C, D, etc, as they are loaded.

The following trivial patch seems to fix this, and I have not encountered any
problems so far with it.


--- D:/paul/desktop.el    Fri Apr 08 08:21:40 2011
+++ D:/paul/desktop-new.el    Fri Apr 08 08:22:27 2011
@@ -1082,9 +1082,7 @@
             (cdr (assq 'buffer-file-coding-system
                    desktop-buffer-locals))))
            (buf (find-file-noselect desktop-buffer-file-name)))
-      (condition-case nil
-          (switch-to-buffer buf)
-        (error (pop-to-buffer buf)))
+          (set-buffer buf)
       (and (not (eq major-mode desktop-buffer-major-mode))
            (functionp desktop-buffer-major-mode)
            (funcall desktop-buffer-major-mode))


Also, I have written an emacs extension called 'slothful' which allows
true lazy loading of files - instead of actually loading the file, an
empty buffer is created pointing the file, and it automatically loads
only when the buffer is first displayed. I think this might be an
interesting addition to desktop. I have tested it myself, just loading
individual files.

If anyone wants to have a look at it the repository is at:

https://bitbucket.org/eeeickythump/slothful

Cheers
Paul

Re: Suggested patch for desktop.el, and 'slothful' lazy file loading

[Davis Herring]

> I have been using desktop.el in "lazy" mode i.e. with the settings
> 
> (setq desktop-restore-eager 10)
> (setq desktop-lazy-verbose nil)
> 
> This is supposed to make it load the first 10 files normally, then load the 
> rest "in the background" when Emacs is idle.
> 
> I have found that although the extra buffers are loaded in the
> background, after each buffer is loaded the display still switches to
> that buffer. This is very disconcerting - you are trying to work in 
> buffer A but you are constantly switched against your will to
> viewing buffer B, C, D, etc, as they are loaded.

I can't reproduce this (but I only have an old Emacs 22 to hand to test).

> The following trivial patch seems to fix this, and I have not encountered any
> problems so far with it.

I suppose that we use switch-to-buffer because it affects the buffer
list order, but I'm not sure; the reordering code is complicated and its
true goal is unclear.  If we can use `set-buffer', we can just use
`with-current-buffer'.

> Also, I have written an emacs extension called 'slothful' which allows
> true lazy loading of files - instead of actually loading the file, an
> empty buffer is created pointing the file, and it automatically loads
> only when the buffer is first displayed. I think this might be an
> interesting addition to desktop. I have tested it myself, just loading
> individual files.

A minor point: you can't restore point and mark in such a buffer, so
they would be lost at the next desktop-save.

Davis

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