Add more generic gst source manager object

Use device manager to add/remove all video providers dynamically, remove
v4l2 specific code.

Get the client proxy from subscribe instead of waiting for the
subscription callback. This way we can actually make an error on
failure.

Clean up the objects when the server disappears.

Remove subscription from the server, we don't need it. Install server
objects in bus_acquired.

src/client/pv-context.c

@@ -307,6 +307,33 @@ context_set_state (PvContext *context, PvContextState state)
     g_object_notify (G_OBJECT (context), "state");
   }
 }
+static void
+on_client_proxy (GObject *source_object,
+                 GAsyncResult *res,
+                 gpointer user_data)
+{
+  PvContext *context = user_data;
+  PvContextPrivate *priv = context->priv;
+  GError *error = NULL;
+
+  priv->client = pv_subscribe_get_proxy_finish (priv->subscribe,
+                                                res,
+                                                &error);
+  if (priv->client == NULL)
+    goto client_failed;
+
+  context_set_state (context, PV_CONTEXT_STATE_READY);
+
+  return;
+
+client_failed:
+  {
+    priv->error = error;
+    context_set_state (context, PV_STREAM_STATE_ERROR);
+    g_error ("failed to get client proxy: %s", error->message);
+    return;
+  }
+}
 
 static void
 on_client_connected (GObject *source_object,
@@ -330,6 +357,14 @@ on_client_connected (GObject *source_object,
 
   g_variant_get (ret, "(o)", &priv->client_path);
   g_variant_unref (ret);
+
+  pv_subscribe_get_proxy (priv->subscribe,
+                          PV_DBUS_SERVICE,
+                          priv->client_path,
+                          "org.pulsevideo.Client1",
+                          NULL,
+                          on_client_proxy,
+                          context);
 }
 
 static void
@@ -372,10 +407,6 @@ subscription_cb (PvSubscribe         *subscribe,
       break;
 
     case PV_SUBSCRIPTION_FLAGS_CLIENT:
-      if (g_strcmp0 (g_dbus_proxy_get_object_path (object), priv->client_path) == 0) {
-        priv->client = object;
-        context_set_state (context, PV_CONTEXT_STATE_READY);
-      }
       break;
 
     case PV_SUBSCRIPTION_FLAGS_SOURCE:

src/client/pv-introspect.c

@@ -49,7 +49,7 @@ pv_context_list_source_info (PvContext *context,
     GDBusProxy *proxy = walk->data;
     PvSourceInfo info;
 
-    info.name = "v4l2";
+    info.name = "gst";
 
     cb (context, &info, user_data);
   }

src/client/pv-subscribe.c

@@ -134,17 +134,28 @@ object_data_free (PvObjectData *data)
 static void
 remove_data (PvSubscribe *subscribe, PvObjectData *data)
 {
-  PvSubscribePrivate *priv = subscribe->priv;
-
   if (data->pending) {
     data->removed = TRUE;
   } else {
-    priv->objects = g_list_remove (priv->objects, data);
     notify_event (subscribe, data, PV_SUBSCRIPTION_EVENT_REMOVE);
     object_data_free (data);
   }
 }
 
+static void
+remove_all_data (PvSubscribe *subscribe)
+{
+  PvSubscribePrivate *priv = subscribe->priv;
+  GList *walk;
+
+  for (walk = priv->objects; walk; walk = g_list_next (walk)) {
+    PvObjectData *data = walk->data;
+    remove_data (subscribe, data);
+  }
+  g_list_free (priv->objects);
+  priv->objects = NULL;
+}
+
 static void
 on_proxy_created (GObject *source_object,
                   GAsyncResult *res,
@@ -185,8 +196,10 @@ on_proxy_created (GObject *source_object,
   if (--priv->pending_proxies == 0)
     subscription_set_state (subscribe, PV_SUBSCRIPTION_STATE_READY);
 
-  if (data->removed)
+  if (data->removed) {
+    priv->objects = g_list_remove (priv->objects, data);
     remove_data (subscribe, data);
+  }
 }
 
 
@@ -233,6 +246,7 @@ remove_interface (PvSubscribe *subscribe,
 
     if (g_strcmp0 (data->object_path, object_path) == 0 &&
         g_strcmp0 (data->interface_name, interface_name) == 0) {
+      priv->objects = g_list_remove (priv->objects, data);
       remove_data (subscribe, data);
       break;
     }
@@ -364,6 +378,7 @@ manager_proxy_appeared (PvSubscribe *subscribe)
 static void
 manager_proxy_disappeared (PvSubscribe *subscribe)
 {
+  remove_all_data (subscribe);
 }
 
 static void