cpio-mode

cpio-mode

[Douglas Lewan]

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All,

Two or three years ago I joined this mailing list and announced that I
wanted to write a cpio mode for emacs.

Well, after various surprising events and mishaps I'm back, and expect to
have something worth showing soon.

What is the customary way of sharing such code? I'm currently working under
CVS on my local box and expect to continue doing my detailed work there,
but if there's a preferred way to share, then I'd like to integrate that.

Thanks.

-- 
,Doug
Douglas Lewan
(908) 720-7908
What one programmer can do in one month, two programmers can do in two
months. -- Fred Brooks

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Re: cpio-mode

[Michael Albinus]

Douglas Lewan <d.lewan2000@gmail.com> writes:

> All,

Hi Doug,

> Two or three years ago I joined this mailing list and announced that I
> wanted to write a cpio mode for emacs.
>
> Well, after various surprising events and mishaps I'm back, and expect
> to have something worth showing soon.

Time passes, and I have committed tramp-archive.el to Emacs' master
branch, which supports also cpio archives (read-only for now). See
<http://lists.gnu.org/archive/html/emacs-devel/2017-12/msg00263.html>.

Could you pls compare this with your work?

> Thanks.

Best regards, Michael.

Re: cpio-mode

[Douglas Lewan]

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Michael,

First: Oh, my! I've been reading about a missing cpio mode in the emacs
TODO file for years, I'd sort of assumed that there was little work on it.
(I do admit that when I'd last joined this list, I did receive a few
attempts to start such a project.)

Your work sounds similar to mine. Indeed, my goal is to write something
like a dired front end to all the cpio formats, with relatively easy
extensibility to others. This should include editing, adding and deleting
archive members. That's turned out to be a little more than I was
expecting. Once I started looking more closely, dired is much larger that I
was expecting.

FYI The design is coarsely given in this diagram.

;; +----------------------+   +-------------+   +-------------+
;; | Format specific code |   |             |   |             |
;; | +---------------+    |   |             |   |             |
;; | | cpio-bin      |    |   |             |   |             |
;; | | +--------------+   |   |    CPIO     |   | dired-like  |
;; | +-|cpio-crc      |   |<->|    Logic    |<->|     UI      |
;; |   | +-------------+  |   |             |   |             |
;; |   +-| hpbin       |  |   |             |   |             |
;; |     | +------------+ |   |             |   |             |
;; |     +-| ···        | |   |             |   |             |
;; |       +------------+ |   |             |   |             |
;; +----------------------+   +-------------+   +-------------+
;;             Λ                     Λ                 Λ
;;             |                     |                 |
;;             V                     V                 V
;; +----------------------------------------------------------+
;; | generic code                                             |
;; |          +------------+ +--------------+ +-----+         |
;; |          | cpio-modes | | cpio-generic | | ··· |         |
;; |          +------------+ +--------------+ +-----+         |
;; +----------------------------------------------------------+

Could you point me to your code? Thanks.


On Fri, Feb 2, 2018 at 8:48 AM, Michael Albinus <michael.albinus@gmx.de>
wrote:

> Douglas Lewan <d.lewan2000@gmail.com> writes:
>
> > All,
>
> Hi Doug,
>
> > Two or three years ago I joined this mailing list and announced that I
> > wanted to write a cpio mode for emacs.
> >
> > Well, after various surprising events and mishaps I'm back, and expect
> > to have something worth showing soon.
>
> Time passes, and I have committed tramp-archive.el to Emacs' master
> branch, which supports also cpio archives (read-only for now). See
> <http://lists.gnu.org/archive/html/emacs-devel/2017-12/msg00263.html>.
>
> Could you pls compare this with your work?
>
> > Thanks.
>
> Best regards, Michael.
>



-- 
,Doug
Douglas Lewan
(908) 720-7908
What one programmer can do in one month, two programmers can do in two
months. -- Fred Brooks

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Re: cpio-mode

[Michael Albinus]

Douglas Lewan <d.lewan2000@gmail.com> writes:

> Michael,

Hi Doug,

> First: Oh, my! I've been reading about a missing cpio mode in the
> emacs TODO file for years, I'd sort of assumed that there was little
> work on it. (I do admit that when I'd last joined this list, I did
> receive a few attempts to start such a project.)

I haven't updated the TODO file yet, so you wouldn't still know it ...

> Your work sounds similar to mine. Indeed, my goal is to write
> something like a dired front end to all the cpio formats, with
> relatively easy extensibility to others.

That fits perfectly. I have written a *back end*, based on the file name
handler approach of Emacs. See (info "(elisp) Magic File Names")

In fact, most of the basic operations mentioned there got a new
implementation in file .../lisp/net/tramp-archive.el. You don't need to
configure anything in your Emacs, those alternative implementations come
into play based on the file name. Just open the virtual file
"/path/to/file.cpio/", and you have a dired buffer with the contents of
the archive. Call (copy-file "/path/to/file.cpio/foo" "/tmp") etc pp.

I have written something about in the Tramp manual, check
(info "(tramp) Archive file names")

There are also test cases which could give you an impression what's
possible, see .../test/lisp/net/tramp-archive-tests.el.

This implementation has some limitations, though. It is based on GVFS,
the Gnome Virtual File System. In practice, it works only for GNU/Linux
systems. Another drawback is, that the Gnome folks haven't implemented
write access for archives, although it would be possible. Here I'm still
a little bit undecided how to continue.

> This should include editing,
> adding and deleting archive members. That's turned out to be a little
> more than I was expecting. Once I started looking more closely, dired
> is much larger that I was expecting.
>
> FYI The design is coarsely given in this diagram.
>
> ;; +----------------------+   +-------------+   +-------------+
> ;; | Format specific code |   |             |   |             |
> ;; | +---------------+    |   |             |   |             |
> ;; | | cpio-bin      |    |   |             |   |             |
> ;; | | +--------------+   |   |    CPIO     |   | dired-like  |
> ;; | +-|cpio-crc      |   |<->|    Logic    |<->|     UI      |
> ;; |   | +-------------+  |   |             |   |             |
> ;; |   +-| hpbin       |  |   |             |   |             |
> ;; |     | +------------+ |   |             |   |             |
> ;; |     +-| ···        | |   |             |   |             |
> ;; |       +------------+ |   |             |   |             |
> ;; +----------------------+   +-------------+   +-------------+
> ;;             Λ                     Λ                 Λ
> ;;             |                     |                 |
> ;;             V                     V                 V
> ;; +----------------------------------------------------------+
> ;; | generic code                                             |
> ;; |          +------------+ +--------------+ +-----+         |
> ;; |          | cpio-modes | | cpio-generic | | ··· |         |
> ;; |          +------------+ +--------------+ +-----+         |
> ;; +----------------------------------------------------------+
>
> Could you point me to your code? Thanks.

At a first glance, what you call "generic code" could be based on the
back end. Maybe there's something missing, but it could be a starter.

Best regards, Michael.