Use xdo to feed escape keycodes into the focused window prior to

attempting mouse and keyboard grabs.

A frequent barrier to the screensaver starting is a modal window,
application popup menu or cinnamon popup being left open when
the user steps away from their computer. This will have the effect
of cancelling or closing these if they exist.

It sends two keystrokes in the event of a popup menu being raised
by a modal dialog (the first will cancel the popup, the second
the dialog).

note: cinnamon popups could be addressed differently (expo/overview
modes already are), but this wasn't possible with application
popups.

Ref: #93

debian/control

@@ -37,6 +37,7 @@ Depends:
  python3-gi-cairo,
  python3-setproctitle,
  python3-xapp (>= 1.0.1),
+ python3-xdo,
  python3-xlib,
  ${misc:Depends},
  ${python3:Depends},

src/manager.py

@@ -112,6 +112,7 @@ def set_active(self, active, msg=None):
         if active:
             if not status.Active:
                 self.cinnamon_client.exit_expo_and_overview()
+                utils.maybe_cancel_ui_grab()
                 if self.grab_helper.grab_root(False):
                     if not self.stage:
                         Gio.Application.get_default().hold()
@@ -372,6 +373,7 @@ def stage_refreshed(self):
         if status.Debug:
             print("manager: stage refresh complete")
 
+        utils.maybe_cancel_ui_grab()
         self.grab_stage()
 
         if status.Locked:

src/util/utils.py

@@ -5,6 +5,7 @@
 import grp
 import subprocess
 import xapp.os
+import xdo
 
 import config
 import status
@@ -148,3 +149,12 @@ def clear_clipboards(widget):
 
 def do_quit():
     Gtk.main_quit()
+
+
+# Most popup-menu-type actors and widgets can be closed via the escape key, making sure there's
+# no active grab when the screensaver starts.
+xdo = xdo.xdo()
+
+def maybe_cancel_ui_grab():
+    xdo.send_keysequence_window("Escape")
+    xdo.send_keysequence_window("Escape")