Re: Clipboard and coding systems

[Kenichi Handa <handa@m17n.org>]

In article <871xfuzyo8.fsf@marant.org>, Jérôme Marant <jmarant@nerim.net> writes:

> 2) Start Emacs, type `abéècd' in a fresh buffer, copy the typed text,
> _exit from Emacs_ and paste within the following command in a Xterm:

> amboise:~$ echo 'abéècd' > foo

> Then,

> amboise:~$ hex foo
> 0x00000000: 61 62 8e e9 8e e8 63 64 - 0a                      ab....cdJ

> Can this be explained or is it a bug?

Thank you for the report.  But, I found the fix is not easy.
The explanation is complex and difficult.

This problem is because Emacs stores internal multibyte
sequence into a cut buffer.  So, I at first thought that we
can simply encode STRING by locale-coding-system in
x-set-cut-buffer.  But, then x-cut-buffer-or-selection-value
doesn't work when we copy a string that can't be encoded by
locale-coding-system.  That is because
x-cut-buffer-or-selection-value looks up a cut buffer by
x-get-cut-buffer and compare it with
x-last-selected-text-cut, and they differs.

So, my question is: Should Emacs still support pasting form
an application that uses only a cut buffer?  If not, we can
make x-cut-buffer-or-selection-value not check a cut buffer,
then, we can store encoded string in a cut buffer by
x-set-cut-buffer?

Another way is to solve this problem (the comment before
x-cut-buffer-or-selection-value) not in
x-cut-buffer-or-selection-value.

;;; If this function is called twice and finds the same text,
;;; it returns nil the second time.  This is so that a single
;;; selection won't be added to the kill ring over and over.

---
Ken'ichi HANDA
handa@m17n.org