[gnome-bluetooth/wip/hadess/async-unregister] agent: Fix possible hang when switching Settings panels

[Bastien Nocera <hadess src gnome org>]

commit ac9be930e3809718a325d111b074dd140b2c9f2a
Author: Bastien Nocera <hadess hadess net>
Date:   Fri Feb 19 15:12:46 2021 +0100

    agent: Fix possible hang when switching Settings panels
    
    There are usually 2 reasons why the agent might go away:
    - we're switching panels in the Settings
    - the Settings executable is exit()ing
    
    In the former case, we can't actually do anything if unregistering the
    agent fails, and we can already remove our object path without waiting
    on anyone, so just print some debug if it fails.
    
    In the latter case, we'll be gone from the bus before before the method
    has time to answer.
    
    This fixes possible hangs while unregistering the agent when switching
    panels with some broken Bluetooth adapters and/or drivers.
    
    Closes: #49

 lib/bluetooth-agent.c | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)
---
diff --git a/lib/bluetooth-agent.c b/lib/bluetooth-agent.c
index b005b9ba..d12aa96b 100644
--- a/lib/bluetooth-agent.c
+++ b/lib/bluetooth-agent.c
@@ -513,42 +513,29 @@ gboolean bluetooth_agent_register(BluetoothAgent *agent)
        return TRUE;
 }
 
-static gboolean
-error_matches_remote_error (GError     *error,
-                           const char *remote_error)
+static void
+agent_unregister_cb (GObject      *object,
+                    GAsyncResult *res,
+                    gpointer      user_data)
 {
-       g_autofree char *str = NULL;
-       gboolean ret;
-
-       if (error == NULL)
-               return FALSE;
-
-       str = g_dbus_error_get_remote_error (error);
-       ret = (g_strcmp0 (str, remote_error) == 0);
+       g_autoptr(GError) error = NULL;
 
-       return ret;
+       if (!agent_manager1_call_unregister_agent_finish (AGENT_MANAGER1 (object), res, &error))
+               g_debug ("Failed to unregister agent: %s", error->message);
+       else
+               g_debug ("Unregistered agent successfully");
 }
 
 gboolean bluetooth_agent_unregister(BluetoothAgent *agent)
 {
-       g_autoptr(GError) error = NULL;
-
        g_return_val_if_fail (BLUETOOTH_IS_AGENT (agent), FALSE);
 
        if (agent->agent_manager == NULL)
                return FALSE;
 
-       if (agent_manager1_call_unregister_agent_sync (agent->agent_manager,
-                                                      agent->path,
-                                                      NULL, &error) == FALSE) {
-               /* Ignore errors if the adapter is gone */
-               if (g_error_matches (error, G_DBUS_ERROR, G_DBUS_ERROR_UNKNOWN_METHOD) == FALSE &&
-                   error_matches_remote_error (error, "org.bluez.Error.DoesNotExist") == FALSE) {
-                       g_printerr ("Agent unregistration failed: %s '%s'\n",
-                                   error->message,
-                                   g_quark_to_string (error->domain));
-               }
-       }
+       agent_manager1_call_unregister_agent (agent->agent_manager,
+                                             agent->path,
+                                             NULL, agent_unregister_cb, NULL);
 
        g_clear_object (&agent->agent_manager);
        g_clear_pointer (&agent->path, g_free);