bug#24652: 25.1.50; gui-backend-get-selection does not work in xterm frame

[Olaf Rogalsky]

Hi emacs,

I try to get `gui-backend-get-selection' to work with xterm:

# In a xterm (version 324):
# 1.) put some text into the clipboard:
echo foobar | xsel -i -b
# 2.) try to insert the clipboard into a fresh *scratch* buffer:
emacs -nw -Q --eval "(progn (xterm--init-activate-get-selection) (insert 
(gui-backend-get-selection 'CLIPBOARD 'STRING)))"

No text from the clipboard is inserted, instead "Quit" is displayed in
the echo area.

# 3.) for further insight, lets do the same with (setq inhibit-quit t):
emacs -nw -Q --eval "(progn (setq inhibit-quit t) 
(xterm--init-activate-get-selection) (insert (gui-backend-get-selection 
'CLIPBOARD 'STRING)))"

Now the clipboard content is inserted!

My undestanding of the problem is: The xterm escape sequence to query the 
clipboard content is:

   "\e]52;p;?\a"

and xterm responds to this with

   "\e]52;p;<base64-encoded-clipboard-content>\a"

Note, that the last character of the response is an "\a", which is the
same as the keyboard quit key "\C-g" and hence, the
gui-backend-get-selection command is aborted before finsishing its work.

Possible solution: There is an alternative escape sequence for querying
the clipoard content:

   "\e]52;p;?\e\\"

and the response to this is

   "\e]52;p;<base64-encoded-clipboard-content>\e\\"

which does not suffer from the "\C-g" abortion.

Thanks, Olaf






In GNU Emacs 25.1.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8, cairo 
version 1.13.1)
 of 2016-09-21 built on blaubaer
Repository revision: d9741b61c8e446de084cc4dc609aaa8e5702118d
System Description:     Ubuntu 14.04.4 LTS

Recent messages:
Mark saved where search started
Making completion list...
Quit
Composing main Info directory...done
Making completion list...
C-x n C-g is undefined
Updating buffer list...done
Commands: m, u, t, RET, g, k, S, D, Q; q to quit; h for help
Entering debugger...
Quit [2 times]

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