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Re: File watch support in autorevert.el
From: |
Eli Zaretskii |
Subject: |
Re: File watch support in autorevert.el |
Date: |
Fri, 11 Jan 2013 12:05:51 +0200 |
> From: Michael Albinus <address@hidden>
> Date: Thu, 10 Jan 2013 15:28:27 +0100
>
> As a proof of concept, I have installed a patch in autorevert.el
> implementing file watches. This shall work for `auto-revert-mode' and
> `global-auto-revert-mode' for buffers visiting files.
> `auto-revert-tail-mode' is not supported (yet).
Thanks.
> The implementation uses `inotify-*-watch' functions. I have also added
> the calls for `w32-*-watch' functions, but this is untested.
The functions' names are w32notify-*-watch. I fixed that in the trunk
revision 111482. I also did some simple testing, and it seems to
generally work (but see the problems described below).
> Any feedback is welcome.
My feedback is as follows:
. The code as written is too naive: it blindly assumes that every
single notification reported by the filesystem for a given watch is
necessarily the one requested in the auto-revert-notify-add-watch
call. But that assumption is false, at least on Windows, where the
implementation actually watches events to the entire parent
directory of the file we are interested in. So Emacs reverts the
file whenever _any_ file in the same directory was changed. I
believe similar problems can happen with inotify, albeit much more
rarely. For that reason, I think auto-revert-notify-handler should
filter events by ASPECTS/ACTION member, and on Windows also by FILE
member of the event.
. It isn't clear to me that using IN_CLOSE_WRITE with inotify is TRT:
AFAIU, that would mean we only revert a file when the application
writing to it closes its descriptor. IOW, if the application makes
several changes to the file during a prolonged operation, and
doesn't close and reopen the file in between, we will only see the
changes at the end, but not during the operation. Wouldn't it be
better to use IN_MODIFY instead?
. At least on Windows, turning on auto-revert-mode and then modifying
and saving the file announces that it was auto-reverted. This
didn't happen with the auto-revert method that doesn't use file
notifications. Is this a bug?
. I believe some of the features added to autorevert.el, such as a
hash list of watch descriptors, should be in some infrastructure
with appropriate APIs.
- File watch support in autorevert.el, Michael Albinus, 2013/01/10
- Re: File watch support in autorevert.el, Stefan Monnier, 2013/01/10
- Re: File watch support in autorevert.el,
Eli Zaretskii <=
- Re: File watch support in autorevert.el, Stefan Monnier, 2013/01/11
- Re: File watch support in autorevert.el, Eli Zaretskii, 2013/01/11
- Re: File watch support in autorevert.el, Michael Albinus, 2013/01/11
- Re: File watch support in autorevert.el, Eli Zaretskii, 2013/01/11
- Re: File watch support in autorevert.el, Michael Albinus, 2013/01/11
- Re: File watch support in autorevert.el, Eli Zaretskii, 2013/01/11
- Re: File watch support in autorevert.el, Michael Albinus, 2013/01/11
- Re: File watch support in autorevert.el, Stefan Monnier, 2013/01/11
- Re: File watch support in autorevert.el, Michael Albinus, 2013/01/11
- Re: File watch support in autorevert.el, Eli Zaretskii, 2013/01/12