Re: [PCL-CVS] Interactive diff on a utf-8 encoded file

[Kevin Rodgers <ihs_4664@yahoo.com>]

[Followup-To: gnu.emacs.bug]

Jérôme Haguet wrote:

> Hello
> It does not seems to work.
> The following line
> (cvs-coding-system buffer-file-coding-system)
> return the coding-system of *cvs* buffer.


Yes, I was afraid it might.


> I replace it with
> (cvs-coding-system (find-operation-coding-system 'insert-file-contents
> file)))
> and it give me so far a good result ...


Great!

> But I do not know if it is the correct way to do it.


I think it might be more reliable to use buffer-file-coding-system if
the file is being visited in a buffer (which it ought to be), and only
fall back on find-operation-coding-system otherwise.  Also, that
function may return "a coding system, a cons of coding systems, or a
function symbol to call".

So I went looking through the sources to see how it's result is used.
Unfortunately, it's not very consistent, but there's a great example
for us to follow (which supports both points above): vc-coding-system-for-diff

Here's my latest version, based on that:


(defun cvs-retrieve-revision (fileinfo rev)
  "Retrieve the given REVision of the file in FILEINFO into a new buffer."
  (let* ((file (cvs-fileinfo->full-path fileinfo))
	 (rev-file (concat file "." rev)))
    (or (find-buffer-visiting rev-file)
        (let* ((buffer (find-buffer-visiting file))
               (coding-system (cond ((eq buffer (current-buffer))
                                     buffer-file-coding-system)
                                    (buffer (with-current-buffer buffer
                                              buffer-file-coding-system))
                                    (t (find-operation-coding-system
                                        'insert-file-contents
                                        file)))))
          (with-current-buffer (create-file-buffer rev-file)
            (message "Retrieving revision %s..." rev)
            (let* ((coding-system-for-read coding-system)
                   (res (call-process cvs-program nil t nil
                                      "-q" "update" "-p" "-r" rev file)))
              (when (and res (not (and (equal 0 res))))
                (error "Something went wrong retrieving revision %s: %s"
                       rev res))
              (set-buffer-modified-p nil)
              (let ((buffer-file-name (expand-file-name file)))
                (after-find-file))
              (toggle-read-only 1)
              (message "Retrieving revision %s... Done" rev)
              (current-buffer)))))))

> Last detail, the coding-system is still not correctly displayed at the
> lower-left corner of the window.

Hmmm, I'll forward that to gnu.emacs.bug along with our cvs-retrieve-revision.

-- 
Kevin Rodgers