Linux/GTK X11 CLIPBOARD and PRIMARY clipboard sync

clipper.py

#!/usr/bin/python3
#
# Keep the X primary selection and the clipboard
# in sync. Polls regularly and, when one changes,
# it's copied to the other.
#
# To the extent possible under law, Alun Jones has waived all copyright and
# related or neighbouring rights to this work. This work is published from:
# United Kingdom.
#
# From https://www.ty-penguin.org.uk/~auj/blog/2019/05/24/clipper/
#
# If you are using XWayland you may need to set the environment variable
# GDK_BACKEND=x11 (otherwise the 'owner-change' signal is never received).

import gi
gi.require_version("Gtk", "3.0")
from gi.repository import Gtk, GLib, Gdk

class Clipper():
    cb = []
    waiting_for_clipboard = False

    def __init__(self):
        for board in (Gdk.SELECTION_PRIMARY, Gdk.SELECTION_CLIPBOARD):
            cb = Gtk.Clipboard.get(board)
            cb.connect('owner-change', self.changed)
            self.cb.append(cb)
        self.oldtext = None

    def changed(self, clipboard, event):
        if not self.waiting_for_clipboard:
            # Avoid infinite recursion if changed() is called again
            self.waiting_for_clipboard = True
            ct = clipboard.wait_for_text()
            self.waiting_for_clipboard = False

            if ct is not None and ct != self.oldtext:
                self.oldtext = ct
                for cb in self.cb:
                    if cb != clipboard:
                        cb.set_text(ct, -1)

    def run(self):
        Gtk.main()

Clipper().run()