[gnome-media] Avoid crashing when switching profiles quickly

[Bastien Nocera <hadess src gnome org>]

commit 1c7dbbecaeaef26d6228fc841ce142bdcafec961
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Sep 16 16:36:58 2009 +0100

    Avoid crashing when switching profiles quickly
    
    When switching profiles quickly, we were getting callbacks
    about old operations which we're not interested in, because
    they don't match the latest requested profile.
    
    So keep track of the last requested change, and cancel already
    running operations when asking for a new profile.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=595438

 gnome-volume-control/src/gvc-mixer-card.c |   25 +++++++++++++++----------
 1 files changed, 15 insertions(+), 10 deletions(-)
---
diff --git a/gnome-volume-control/src/gvc-mixer-card.c b/gnome-volume-control/src/gvc-mixer-card.c
index 9037ff2..dc4ccca 100644
--- a/gnome-volume-control/src/gvc-mixer-card.c
+++ b/gnome-volume-control/src/gvc-mixer-card.c
@@ -47,6 +47,7 @@ struct GvcMixerCardPrivate
         char          *target_profile;
         char          *human_profile;
         GList         *profiles;
+        pa_operation  *profile_op;
 };
 
 enum
@@ -209,6 +210,9 @@ _pa_context_set_card_profile_by_index_cb (pa_context                       *cont
         }
         g_free (card->priv->target_profile);
         card->priv->target_profile = NULL;
+
+        pa_operation_unref (card->priv->profile_op);
+        card->priv->profile_op = NULL;
 }
 
 gboolean
@@ -223,25 +227,26 @@ gvc_mixer_card_change_profile (GvcMixerCard *card,
                 return TRUE;
         if (g_strcmp0 (profile, card->priv->target_profile) == 0)
                 return TRUE;
+        if (card->priv->profile_op != NULL) {
+                pa_operation_cancel (card->priv->profile_op);
+                pa_operation_unref (card->priv->profile_op);
+                card->priv->profile_op = NULL;
+        }
 
         if (card->priv->profile != NULL) {
-                pa_operation *o;
-
                 g_free (card->priv->target_profile);
                 card->priv->target_profile = g_strdup (profile);
 
-                o = pa_context_set_card_profile_by_index (card->priv->pa_context,
-                                                          card->priv->index,
-                                                          card->priv->target_profile,
-                                                          _pa_context_set_card_profile_by_index_cb,
-                                                          card);
+                card->priv->profile_op = pa_context_set_card_profile_by_index (card->priv->pa_context,
+                                                                               card->priv->index,
+                                                                               card->priv->target_profile,
+                                                                               _pa_context_set_card_profile_by_index_cb,
+                                                                               card);
 
-                if (o == NULL) {
+                if (card->priv->profile_op == NULL) {
                         g_warning ("pa_context_set_card_profile_by_index() failed");
                         return FALSE;
                 }
-
-                pa_operation_unref (o);
         } else {
                 g_assert (card->priv->human_profile == NULL);
                 card->priv->profile = g_strdup (profile);