[rhythmbox] xfade: always handle bus messages on the main thread

[Jonathan Matthew <jmatthew src gnome org>]

commit 38625a66cd1dc10abef89be85b9b2976fc2978bd
Author: Jonathan Matthew <jonathan d14n org>
Date:   Sun Aug 17 00:18:11 2014 +1000

    xfade: always handle bus messages on the main thread
    
    Since all signals emitted from the player need to be emitted on the
    main thread, we can't do anything much with bus messages elsewhere.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734123

 backends/gstreamer/rb-player-gst-xfade.c |   57 +++++++++++++++++++++++------
 1 files changed, 45 insertions(+), 12 deletions(-)
---
diff --git a/backends/gstreamer/rb-player-gst-xfade.c b/backends/gstreamer/rb-player-gst-xfade.c
index 92c45da..d76565e 100644
--- a/backends/gstreamer/rb-player-gst-xfade.c
+++ b/backends/gstreamer/rb-player-gst-xfade.c
@@ -273,6 +273,9 @@ struct _RBPlayerGstXFadePrivate
        guint stream_reap_id;
        guint stop_sink_id;
        guint bus_watch_id;
+
+       guint bus_idle_id;
+       GList *idle_messages;
 };
 
 
@@ -785,6 +788,14 @@ rb_player_gst_xfade_dispose (GObject *object)
 
        g_rec_mutex_lock (&player->priv->sink_lock);
        stop_sink (player);
+
+       if (player->priv->bus_idle_id != 0) {
+               g_source_remove (player->priv->bus_idle_id);
+               player->priv->bus_idle_id = 0;
+
+               rb_list_destroy_free (player->priv->idle_messages, (GDestroyNotify) gst_mini_object_unref);
+               player->priv->idle_messages = NULL;
+       }
        g_rec_mutex_unlock (&player->priv->sink_lock);
 
        if (player->priv->pipeline != NULL) {
@@ -1967,6 +1978,26 @@ rb_player_gst_xfade_bus_cb (GstBus *bus, GstMessage *message, RBPlayerGstXFade *
        return TRUE;
 }
 
+static gboolean
+bus_idle_cb (RBPlayerGstXFade *player)
+{
+       GList *messages, *l;
+       GstBus *bus;
+
+       g_rec_mutex_lock (&player->priv->sink_lock);
+       messages = player->priv->idle_messages;
+       player->priv->idle_messages = NULL;
+       player->priv->bus_idle_id = 0;
+       g_rec_mutex_unlock (&player->priv->sink_lock);
+
+       bus = gst_element_get_bus (GST_ELEMENT (player->priv->pipeline));
+       for (l = messages; l != NULL; l = l->next)
+               rb_player_gst_xfade_bus_cb (bus, l->data, player);
+
+       rb_list_destroy_free (messages, (GDestroyNotify) gst_mini_object_unref);
+       return FALSE;
+}
+
 static void
 stream_source_setup_cb (GstElement *decoder, GstElement *source, RBXFadeStream *stream)
 {
@@ -2570,6 +2601,7 @@ preroll_stream (RBPlayerGstXFade *player, RBXFadeStream *stream)
 {
        GstStateChangeReturn state;
        GstMessage *message;
+       GList *messages;
        GstBus *bus;
 
        stream->block_probe_id =
@@ -2586,15 +2618,21 @@ preroll_stream (RBPlayerGstXFade *player, RBXFadeStream *stream)
        case GST_STATE_CHANGE_FAILURE:
                rb_debug ("preroll for stream %s failed (state change failed)", stream->uri);
 
-               /* process bus messages in case we got a redirect for this stream */
+               /* process messages in an idle handler in case we got a redirect */
                bus = gst_element_get_bus (GST_ELEMENT (player->priv->pipeline));
+               messages = NULL;
                message = gst_bus_pop (bus);
                while (message != NULL) {
-                       rb_player_gst_xfade_bus_cb (bus, message, player);
-                       gst_message_unref (message);
+                       messages = g_list_prepend (messages, message);
                        message = gst_bus_pop (bus);
                }
                g_object_unref (bus);
+
+               g_rec_mutex_lock (&player->priv->sink_lock);
+               player->priv->idle_messages = g_list_concat (player->priv->idle_messages, g_list_reverse 
(messages));
+               if (player->priv->bus_idle_id == 0)
+                       player->priv->bus_idle_id = g_idle_add ((GSourceFunc) bus_idle_cb, player);
+               g_rec_mutex_unlock (&player->priv->sink_lock);
                break;
 
        case GST_STATE_CHANGE_NO_PREROLL:
@@ -2961,8 +2999,6 @@ static gboolean
 start_sink (RBPlayerGstXFade *player, GError **error)
 {
        GList *messages = NULL;
-       GList *t;
-       GstBus *bus;
        gboolean ret;
 
        g_rec_mutex_lock (&player->priv->sink_lock);
@@ -2975,6 +3011,10 @@ start_sink (RBPlayerGstXFade *player, GError **error)
                /* prevent messages from being processed by the main thread while we're starting the sink */
                g_source_remove (player->priv->bus_watch_id);
                ret = start_sink_locked (player, &messages, error);
+
+               player->priv->idle_messages = g_list_concat (player->priv->idle_messages, messages);
+               if (player->priv->bus_idle_id == 0)
+                       player->priv->bus_idle_id = g_idle_add ((GSourceFunc) bus_idle_cb, player);
                add_bus_watch (player);
                break;
 
@@ -2987,13 +3027,6 @@ start_sink (RBPlayerGstXFade *player, GError **error)
        }
        g_rec_mutex_unlock (&player->priv->sink_lock);
 
-       bus = gst_element_get_bus (GST_ELEMENT (player->priv->pipeline));
-       for (t = messages; t != NULL; t = t->next) {
-               rb_player_gst_xfade_bus_cb (bus, t->data, player);
-       }
-       gst_object_unref (bus);
-
-       rb_list_destroy_free (messages, (GDestroyNotify) gst_mini_object_unref);
        return ret;
 }