[mutter/wip/carlosg/remote-session-checks: 3/4] backends: Ensure remote desktop dbus interface state

[Carlos Garnacho <carlosg src gnome org>]

commit b1651130f7404fe56b5ffe24c6e71e825e853a01
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat May 16 10:44:04 2020 +0200

    backends: Ensure remote desktop dbus interface state
    
    Ensure that it does receive Start and Stop orderly, and error out
    otherwise.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1258

 src/backends/meta-remote-desktop-session.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/meta-remote-desktop-session.c b/src/backends/meta-remote-desktop-session.c
index 059e1e878..48b0c2e29 100644
--- a/src/backends/meta-remote-desktop-session.c
+++ b/src/backends/meta-remote-desktop-session.c
@@ -55,6 +55,7 @@ struct _MetaRemoteDesktopSession
 
   MetaScreenCastSession *screen_cast_session;
   gulong screen_cast_session_closed_handler_id;
+  guint started : 1;
 
   ClutterVirtualInputDevice *virtual_pointer;
   ClutterVirtualInputDevice *virtual_keyboard;
@@ -119,7 +120,7 @@ meta_remote_desktop_session_start (MetaRemoteDesktopSession *session,
   ClutterBackend *backend = clutter_get_default_backend ();
   ClutterSeat *seat = clutter_backend_get_default_seat (backend);
 
-  g_assert (!session->virtual_pointer && !session->virtual_keyboard);
+  g_assert (!session->started);
 
   if (session->screen_cast_session)
     {
@@ -135,6 +136,7 @@ meta_remote_desktop_session_start (MetaRemoteDesktopSession *session,
     clutter_seat_create_virtual_device (seat, CLUTTER_TOUCHSCREEN_DEVICE);
 
   init_remote_access_handle (session);
+  session->started = TRUE;
 
   return TRUE;
 }
@@ -145,6 +147,8 @@ meta_remote_desktop_session_close (MetaRemoteDesktopSession *session)
   MetaDBusRemoteDesktopSession *skeleton =
     META_DBUS_REMOTE_DESKTOP_SESSION (session);
 
+  session->started = FALSE;
+
   if (session->screen_cast_session)
     {
       g_clear_signal_handler (&session->screen_cast_session_closed_handler_id,
@@ -256,6 +260,14 @@ handle_start (MetaDBusRemoteDesktopSession *skeleton,
   MetaRemoteDesktopSession *session = META_REMOTE_DESKTOP_SESSION (skeleton);
   GError *error = NULL;
 
+  if (session->started)
+    {
+      g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Already started");
+      return TRUE;
+    }
+
   if (!check_permission (session, invocation))
     {
       g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
@@ -288,6 +300,14 @@ handle_stop (MetaDBusRemoteDesktopSession *skeleton,
 {
   MetaRemoteDesktopSession *session = META_REMOTE_DESKTOP_SESSION (skeleton);
 
+  if (!session->started)
+    {
+      g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Session not started");
+      return TRUE;
+    }
+
   if (!check_permission (session, invocation))
     {
       g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,