[libgovirt] proxy: Check if operation is cancelled before disconnecting signal

[Christophe Fergeau <teuf src gnome org>]

commit 65b5fce90f34f7b52801f09daa28696e53468bae
Author: Eduardo Lima (Etrunko) <etrunko redhat com>
Date:   Thu Feb 2 15:13:48 2017 -0200

    proxy: Check if operation is cancelled before disconnecting signal
    
    According to the documentation, g_cancellable_disconnect() waits for the
    signal handler to finish, and if it is called from the handler itself, it
    will result in a deadlock. To avoid it, we check if the operation is
    cancelled and if so, call g_signal_handler_disconnect() instead of
    g_cancellable_disconnect().
    
    https://developer.gnome.org/gio/stable/GCancellable.html#g-cancellable-disconnect
    
    Signed-off-by: Eduardo Lima (Etrunko) <etrunko redhat com>

 govirt/ovirt-proxy.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/govirt/ovirt-proxy.c b/govirt/ovirt-proxy.c
index 70c08ac..73c4d4a 100644
--- a/govirt/ovirt-proxy.c
+++ b/govirt/ovirt-proxy.c
@@ -216,7 +216,15 @@ static void ovirt_proxy_call_async_data_free(OvirtProxyCallAsyncData *data)
             g_object_unref(G_OBJECT(data->result));
         }
         if ((data->cancellable != NULL) && (data->cancellable_cb_id != 0)) {
-            g_cancellable_disconnect(data->cancellable, data->cancellable_cb_id);
+            if (g_cancellable_is_cancelled(data->cancellable)) {
+                /* Cancellable has already been cancelled, we don't need to use
+                 * g_cancellable_disconnect() to disconnect the signal handler
+                 * as we know the 'cancelled' signal is no longer going to be emitted
+                 */
+                g_signal_handler_disconnect(data->cancellable, data->cancellable_cb_id);
+            } else {
+                g_cancellable_disconnect(data->cancellable, data->cancellable_cb_id);
+            }
         }
         g_clear_object(&data->cancellable);
         g_slice_free(OvirtProxyCallAsyncData, data);