[GTK] Improve detecting X11 display server

GdkX11 still imports on Wayland so check display server is X11 before
importing.

deluge/ui/gtk3/addtorrentdialog.py

@@ -34,7 +34,12 @@ from deluge.httpdownloader import download_file
 from deluge.ui.client import client
 from deluge.ui.common import TorrentInfo
 
-from .common import get_clipboard_text, listview_replace_treestore, reparent_iter
+from .common import (
+    get_clipboard_text,
+    listview_replace_treestore,
+    reparent_iter,
+    windowing,
+)
 from .dialogs import ErrorDialog
 from .edittrackersdialog import trackers_tiers_from_text
 from .path_chooser import PathChooser
@@ -174,11 +179,8 @@ class AddTorrentDialog(component.Component):
         self.dialog.present()
         if focus:
             timestamp = main_window.get_timestamp()
-            try:
+            if windowing('X11'):
                 self.dialog.get_window().set_user_time(timestamp)
-            except AttributeError:
-                # Not an X11 windowing system
-                pass
 
     def hide(self):
         self.dialog.hide()

deluge/ui/gtk3/common.py

@@ -16,7 +16,7 @@ import shutil
 import sys
 
 import six.moves.cPickle as pickle  # noqa: N813
-from gi.repository.Gdk import SELECTION_CLIPBOARD
+from gi.repository.Gdk import SELECTION_CLIPBOARD, Display
 from gi.repository.GdkPixbuf import Colorspace, Pixbuf
 from gi.repository.GLib import GError
 from gi.repository.Gtk import (
@@ -389,3 +389,7 @@ def get_clipboard_text():
     )
     if text:
         return text.strip()
+
+
+def windowing(like):
+    return like.lower() in str(type(Display.get_default())).lower()

deluge/ui/gtk3/gtkui.py

@@ -22,7 +22,6 @@ gi.require_version('Gtk', '3.0')  # NOQA: E402
 gi.require_version('Gdk', '3.0')  # NOQA: E402
 
 # isort:imports-thirdparty
-from gi.repository.Gdk import Display
 from gi.repository.GLib import set_prgname
 from gi.repository.Gtk import Builder, ResponseType
 from twisted.internet import defer, gtk3reactor
@@ -55,7 +54,7 @@ from deluge.ui.tracker_icons import TrackerIcons
 
 # isort:imports-localfolder
 from .addtorrentdialog import AddTorrentDialog
-from .common import associate_magnet_links
+from .common import associate_magnet_links, windowing
 from .connectionmanager import ConnectionManager
 from .dialogs import YesNoDialog
 from .filtertreeview import FilterTreeView
@@ -139,10 +138,6 @@ DEFAULT_PREFS = {
 }
 
 
-def windowing(like):
-    return like.lower() in str(type(Display.get_default())).lower()
-
-
 class GtkUI(object):
     def __init__(self, args):
         # Setup gtkbuilder/glade translation

deluge/ui/gtk3/mainwindow.py

@@ -24,17 +24,18 @@ from deluge.common import decode_bytes, fspeed, resource_filename
 from deluge.configmanager import ConfigManager
 from deluge.ui.client import client
 
-from .common import get_deluge_icon
+from .common import get_deluge_icon, windowing
 from .dialogs import PasswordDialog
 from .ipcinterface import process_args
 
-try:
+GdkX11 = None
-    from gi.repository import GdkX11
-except ImportError:
-    GdkX11 = None
-
 Wnck = None
-if GdkX11:
+if windowing('X11'):
+    try:
+        from gi.repository import GdkX11
+    except ImportError:
+        pass
+
     try:
         gi.require_version('Wnck', '3.0')
         from gi.repository import Wnck