[glib/wip/tingping/socketclient-cancel-2] gsocketclient: Fix potential critical when cancelling connect

[Patrick Griffis <pgriffis src gnome org>]

commit 313e7cbad779fb36e3d999474e00a0a249d9f273
Author: Patrick Griffis <pgriffis igalia com>
Date:   Tue Apr 16 10:22:35 2019 -0700

    gsocketclient: Fix potential critical when cancelling connect
    
    We are manually tracking the completion state of the connect task
    so avoid just calling g_task_return_error_if_cancelled() without
    checking that.
    
    Fixes #1747

 gio/gsocketclient.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)
---
diff --git a/gio/gsocketclient.c b/gio/gsocketclient.c
index 83cb945c7..5faa02ecb 100644
--- a/gio/gsocketclient.c
+++ b/gio/gsocketclient.c
@@ -1427,15 +1427,24 @@ g_socket_client_async_connect_complete (GSocketClientAsyncConnectData *data)
       data->connection = (GIOStream *)wrapper_connection;
     }
 
-  if (!g_task_return_error_if_cancelled (data->task))
+  if (!data->completed)
     {
-      g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_COMPLETE, data->connectable, 
data->connection);
-      g_task_return_pointer (data->task, g_steal_pointer (&data->connection), g_object_unref);
+      GError *error = NULL;
+
+      if (g_cancellable_set_error_if_cancelled (g_task_get_cancellable (data->task), &error))
+        {
+          g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_COMPLETE, data->connectable, NULL);
+          g_task_return_error (data->task, g_steal_pointer (&error));
+        }
+      else
+        {
+          g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_COMPLETE, data->connectable, 
data->connection);
+          g_task_return_pointer (data->task, g_steal_pointer (&data->connection), g_object_unref);
+        }
+
+      data->completed = TRUE;
     }
-  else
-    g_socket_client_emit_event (data->client, G_SOCKET_CLIENT_COMPLETE, data->connectable, NULL);
 
-  data->completed = TRUE;
   g_object_unref (data->task);
 }