util.js: Lock the screen before switching to the greeter.

Move some relevant code out of the user applet - calling the
util.switchToGreeter will lock the screen first.

Author: mtwebster

files/usr/share/cinnamon/applets/[email protected]/applet.js

@@ -85,15 +85,7 @@ class CinnamonUserApplet extends Applet.TextApplet {
         if (!Main.lockdownSettings.get_boolean('disable-user-switching')) {
             item = new PopupMenu.PopupIconMenuItem(_("Switch User"), "xsi-switch-user", St.IconType.SYMBOLIC);
             item.connect('activate', Lang.bind(this, function() {
-                let lockedId = Main.screensaverController.connect("locked-changed", () => {
-                    Util.switchToGreeter();
-                    Main.screensaverController.disconnect(lockedId);
-                })
-
-                GLib.idle_add(GLib.PRIORITY_DEFAULT, () => {
-                    Main.screensaverController.lockScreen(false);
-                    return GLib.SOURCE_REMOVE;
-                });
+                Util.switchToGreeter();
             }));
             this.menu.addMenuItem(item);
         }

js/misc/util.js

@@ -817,21 +817,27 @@ function wiggle(actor, params) {
 /**
  * switchToGreeter:
  *
- * Switches to the display manager's login greeter, allowing another user
- * to log in without logging out the current user. Tries multiple display
- * manager methods in order of preference.
+ * Locks the screen and switches to the greeter, allowing another user
+ * to log in without logging out the current user. If the screen is
+ * already locked (e.g. called from the screensaver itself), switches
+ * immediately.
  */
 function switchToGreeter() {
-    GLib.idle_add(GLib.PRIORITY_DEFAULT, _doSwitchToGreeter);
-}
+    let controller = Main.screensaverController;
 
-function _doSwitchToGreeter() {
-    // Check if user switching is locked down
-    if (Main.lockdownSettings.get_boolean('disable-user-switching')) {
-        global.logWarning("User switching is locked down");
-        return GLib.SOURCE_REMOVE;
+    if (controller.locked) {
+        GLib.idle_add(GLib.PRIORITY_DEFAULT, _doSwitchToGreeter);
+        return;
     }
 
+    controller.lockScreen(false, (wasLocked) => {
+        if (!wasLocked)
+            return;
+        GLib.idle_add(GLib.PRIORITY_DEFAULT, _doSwitchToGreeter);
+    });
+}
+
+function _doSwitchToGreeter() {
     if (_processIsRunning('gdm')) {
         // Old GDM
         try {