Re: Friendlier dired experience [CODE INCLUDED]

[Boruch Baum]

On 2020-11-04 20:57, Michael Albinus wrote:
> When I'm working in a remote buffer, "diredc-trash-info" does not
> work. This is because you call shell-command, which runs the command on
> the remote host.
>
> When I have trashed a file, say "/ssh:ford:/tmp/xxx", it appears as
> "/home/albinus/.local/share/Trash/files/xxx", in the local trash can.
> "/home/albinus/.local/share/Trash/info/xxx.trashinfo" contains the line
>
> Path=/ssh%3aford%3a/tmp/xxx
>
> as expected. However, "M-x diredc-trash-restore" returns with the error
>
> dired-rename-file: Renaming: No such file or directory, 
> /home/albinus/.local/share/Trash/files/xxx, /ssh%3aford%3a/tmp/xxx
>
> I believe you must unhexlify the path in the .trashinfo. This is not
> only because of Tramp. A local file "/tmp/file with space", trashed via
> "M-x move-file-to-trash", has the entry
>
> Path=/tmp/file%20with%20space
>
> Calling "M-x diredc-trash-restore" restores it to "/tmp/file%20with%20space".

I was surprised that this turned out so difficult for me to do. The very
simple case for 8-bit ascii was easily handled by unhexlifying, but that
simple case got me thinking about unicode file names. Sure enough, the
trash meta-data for such file names are also hex encoded, but the
standard elisp commands I could find wouldn't handle them. Have I
overlooked something? The following code snippet performs two alternate
techniques (url-unhex-string, stolen-from-emacs-w3m-url-decode-string)
first for a simple case of a file name with an embedded space, and then
on a unicode file name. Only the function shamelessly stolen from the
emacs-w3m package worked for both cases. Tell me I've overlooked
something, please.

(cl-flet
  ((stolen-from-emacs-w3m-url-decode-string (str &optional coding regexp)
     (or regexp (setq regexp "%\\(?:\\([0-9a-f][0-9a-f]\\)\\|0d%0a\\)"))
     (let ((start 0)
         (case-fold-search t))
       (with-temp-buffer
         (set-buffer-multibyte nil)
         (while (string-match regexp str start)
         (insert (substring str start (match-beginning 0))
                (if (match-beginning 1)
                    (string-to-number (match-string 1 str) 16)
                  ?\n))
         (setq start (match-end 0)))
         (insert (substring str start))
         (decode-coding-string
          (buffer-string)
          (or (if (listp coding)
                (with-coding-priority coding
                  (car (detect-coding-region (point-min) (point-max))))
              coding)
              'iso-8859-1))))))
 (dolist (str '("hello%20world"
                "%d7%a9%d7%9c%d7%95%d7%9d%20%d7%a2%d7%95%d7%9c%d7%9d"))
   (insert (format "\n\nurl-unhex: %s\nw3m-url-decode: %s"
     (url-unhex-string str)
     (stolen-from-emacs-w3m-url-decode-string str)))))

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