X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=gst%2Fgstbus.c;h=cddaf390b864f64c44a1839b19e57afe6feb1f38;hb=e6bd5b41935f125bf43e030dcb909c3537d33b31;hp=efb5269e8d4d47d42064d34b7d734f33cdda6c02;hpb=1fbcc71dbdff79d70b0abe1285f694f3d4596564;p=platform%2Fupstream%2Fgstreamer.git

diff --git a/gst/gstbus.c b/gst/gstbus.c
index efb5269..cddaf39 100644
--- a/gst/gstbus.c
+++ b/gst/gstbus.c
@@ -15,12 +15,13 @@
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
  */
 
 /**
  * SECTION:gstbus
+ * @title: GstBus
  * @short_description: Asynchronous message bus subsystem
  * @see_also: #GstMessage, #GstElement
  *
@@ -63,8 +64,6 @@
  *
  * Note that a #GstPipeline will set its bus into flushing state when changing
  * from READY to NULL state.
- *
- * Last reviewed on 2006-03-12 (0.10.5)
  */
 
 #include "gst_private.h"
@@ -74,12 +73,19 @@
 #endif
 #include <sys/types.h>
 
+#include "gstatomicqueue.h"
 #include "gstinfo.h"
 #include "gstpoll.h"
 
 #include "gstbus.h"
 #include "glib-compat-private.h"
 
+#ifdef G_OS_WIN32
+#  ifndef EWOULDBLOCK
+#  define EWOULDBLOCK EAGAIN    /* This is just to placate gcc */
+#  endif
+#endif /* G_OS_WIN32 */
+
 #define GST_CAT_DEFAULT GST_CAT_BUS
 /* bus signals */
 enum
@@ -99,13 +105,23 @@ enum
 };
 
 static void gst_bus_dispose (GObject * object);
+static void gst_bus_finalize (GObject * object);
 
 static guint gst_bus_signals[LAST_SIGNAL] = { 0 };
 
 struct _GstBusPrivate
 {
+  GstAtomicQueue *queue;
+  GMutex queue_lock;
+
+  GstBusSyncHandler sync_handler;
+  gpointer sync_handler_data;
+  GDestroyNotify sync_handler_notify;
+
+  guint num_signal_watchers;
+
   guint num_sync_message_emitters;
-  GSource *watch_id;
+  GSource *signal_watch;
 
   gboolean enable_async;
   GstPoll *poll;
@@ -113,7 +129,7 @@ struct _GstBusPrivate
 };
 
 #define gst_bus_parent_class parent_class
-G_DEFINE_TYPE (GstBus, gst_bus, GST_TYPE_OBJECT);
+G_DEFINE_TYPE_WITH_PRIVATE (GstBus, gst_bus, GST_TYPE_OBJECT);
 
 static void
 gst_bus_set_property (GObject * object,
@@ -140,6 +156,8 @@ gst_bus_constructed (GObject * object)
     bus->priv->poll = gst_poll_new_timer ();
     gst_poll_get_read_gpollfd (bus->priv->poll, &bus->priv->pollfd);
   }
+
+  G_OBJECT_CLASS (gst_bus_parent_class)->constructed (object);
 }
 
 static void
@@ -148,10 +166,12 @@ gst_bus_class_init (GstBusClass * klass)
   GObjectClass *gobject_class = (GObjectClass *) klass;
 
   gobject_class->dispose = gst_bus_dispose;
+  gobject_class->finalize = gst_bus_finalize;
   gobject_class->set_property = gst_bus_set_property;
   gobject_class->constructed = gst_bus_constructed;
 
-  /* GstBus:enable-async:
+  /**
+   * GstBus::enable-async:
    *
    * Enable async message delivery support for bus watches,
    * gst_bus_pop() and similar API. Without this only the
@@ -159,8 +179,6 @@ gst_bus_class_init (GstBusClass * klass)
    *
    * This property is used to create the child element buses
    * in #GstBin.
-   *
-   * Since: 0.10.33
    */
   g_object_class_install_property (gobject_class, PROP_ENABLE_ASYNC,
       g_param_spec_boolean ("enable-async", "Enable Async",
@@ -176,18 +194,14 @@ gst_bus_class_init (GstBusClass * klass)
    * A message has been posted on the bus. This signal is emitted from the
    * thread that posted the message so one has to be careful with locking.
    *
-   * This signal will not be emitted by default, you have to set up
-   * gst_bus_sync_signal_handler() as a sync handler if you want this
-   * signal to be emitted when a message is posted on the bus, like this:
-   * <programlisting>
-   * gst_bus_set_sync_handler (bus, gst_bus_sync_signal_handler, yourdata);
-   * </programlisting>
+   * This signal will not be emitted by default, you have to call
+   * gst_bus_enable_sync_message_emission() before.
    */
   gst_bus_signals[SYNC_MESSAGE] =
       g_signal_new ("sync-message", G_TYPE_FROM_CLASS (klass),
       G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
       G_STRUCT_OFFSET (GstBusClass, sync_message), NULL, NULL,
-      g_cclosure_marshal_VOID__BOXED, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
+      g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
 
   /**
    * GstBus::message:
@@ -202,19 +216,16 @@ gst_bus_class_init (GstBusClass * klass)
       g_signal_new ("message", G_TYPE_FROM_CLASS (klass),
       G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
       G_STRUCT_OFFSET (GstBusClass, message), NULL, NULL,
-      g_cclosure_marshal_VOID__BOXED, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
-
-  g_type_class_add_private (klass, sizeof (GstBusPrivate));
+      g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
 }
 
 static void
 gst_bus_init (GstBus * bus)
 {
-  bus->queue = gst_atomic_queue_new (32);
-  g_mutex_init (&bus->queue_lock);
-
-  bus->priv = G_TYPE_INSTANCE_GET_PRIVATE (bus, GST_TYPE_BUS, GstBusPrivate);
+  bus->priv = gst_bus_get_instance_private (bus);
   bus->priv->enable_async = DEFAULT_ENABLE_ASYNC;
+  g_mutex_init (&bus->priv->queue_lock);
+  bus->priv->queue = gst_atomic_queue_new (32);
 
   GST_DEBUG_OBJECT (bus, "created");
 }
@@ -224,19 +235,19 @@ gst_bus_dispose (GObject * object)
 {
   GstBus *bus = GST_BUS (object);
 
-  if (bus->queue) {
+  if (bus->priv->queue) {
     GstMessage *message;
 
-    g_mutex_lock (&bus->queue_lock);
+    g_mutex_lock (&bus->priv->queue_lock);
     do {
-      message = gst_atomic_queue_pop (bus->queue);
+      message = gst_atomic_queue_pop (bus->priv->queue);
       if (message)
         gst_message_unref (message);
     } while (message != NULL);
-    gst_atomic_queue_unref (bus->queue);
-    bus->queue = NULL;
-    g_mutex_unlock (&bus->queue_lock);
-    g_mutex_clear (&bus->queue_lock);
+    gst_atomic_queue_unref (bus->priv->queue);
+    bus->priv->queue = NULL;
+    g_mutex_unlock (&bus->priv->queue_lock);
+    g_mutex_clear (&bus->priv->queue_lock);
 
     if (bus->priv->poll)
       gst_poll_free (bus->priv->poll);
@@ -246,6 +257,17 @@ gst_bus_dispose (GObject * object)
   G_OBJECT_CLASS (parent_class)->dispose (object);
 }
 
+static void
+gst_bus_finalize (GObject * object)
+{
+  GstBus *bus = GST_BUS (object);
+
+  if (bus->priv->sync_handler_notify)
+    bus->priv->sync_handler_notify (bus->priv->sync_handler_data);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
 /**
  * gst_bus_new:
  *
@@ -258,9 +280,12 @@ gst_bus_new (void)
 {
   GstBus *result;
 
-  result = g_object_newv (gst_bus_get_type (), 0, NULL);
+  result = g_object_new (gst_bus_get_type (), NULL);
   GST_DEBUG_OBJECT (result, "created new bus");
 
+  /* clear floating flag */
+  gst_object_ref_sink (result);
+
   return result;
 }
 
@@ -272,7 +297,7 @@ gst_bus_new (void)
  * Post a message on the given bus. Ownership of the message
  * is taken by the bus.
  *
- * Returns: TRUE if the message could be posted, FALSE if the bus is flushing.
+ * Returns: %TRUE if the message could be posted, %FALSE if the bus is flushing.
  *
  * MT safe.
  */
@@ -290,13 +315,17 @@ gst_bus_post (GstBus * bus, GstMessage * message)
   GST_DEBUG_OBJECT (bus, "[msg %p] posting on bus %" GST_PTR_FORMAT, message,
       message);
 
+  /* check we didn't accidentally add a public flag that maps to same value */
+  g_assert (!GST_MINI_OBJECT_FLAG_IS_SET (message,
+          GST_MESSAGE_FLAG_ASYNC_DELIVERY));
+
   GST_OBJECT_LOCK (bus);
   /* check if the bus is flushing */
   if (GST_OBJECT_FLAG_IS_SET (bus, GST_BUS_FLUSHING))
     goto is_flushing;
 
-  handler = bus->sync_handler;
-  handler_data = bus->sync_handler_data;
+  handler = bus->priv->sync_handler;
+  handler_data = bus->priv->sync_handler_data;
   emit_sync_message = bus->priv->num_sync_message_emitters > 0;
   GST_OBJECT_UNLOCK (bus);
 
@@ -324,7 +353,7 @@ gst_bus_post (GstBus * bus, GstMessage * message)
     case GST_BUS_PASS:
       /* pass the message to the async queue, refcount passed in the queue */
       GST_DEBUG_OBJECT (bus, "[msg %p] pushing on async queue", message);
-      gst_atomic_queue_push (bus->queue, message);
+      gst_atomic_queue_push (bus->priv->queue, message);
       gst_poll_write_control (bus->priv->poll);
       GST_DEBUG_OBJECT (bus, "[msg %p] pushed on async queue", message);
 
@@ -339,6 +368,8 @@ gst_bus_post (GstBus * bus, GstMessage * message)
       g_cond_init (cond);
       g_mutex_init (lock);
 
+      GST_MINI_OBJECT_FLAG_SET (message, GST_MESSAGE_FLAG_ASYNC_DELIVERY);
+
       GST_DEBUG_OBJECT (bus, "[msg %p] waiting for async delivery", message);
 
       /* now we lock the message mutex, send the message to the async
@@ -346,17 +377,23 @@ gst_bus_post (GstBus * bus, GstMessage * message)
        * the cond will be signalled and we can continue */
       g_mutex_lock (lock);
 
-      gst_atomic_queue_push (bus->queue, message);
+      gst_atomic_queue_push (bus->priv->queue, message);
       gst_poll_write_control (bus->priv->poll);
 
       /* now block till the message is freed */
       g_cond_wait (cond, lock);
+
+      /* we acquired a new ref from gst_message_dispose() so we can clean up */
       g_mutex_unlock (lock);
 
       GST_DEBUG_OBJECT (bus, "[msg %p] delivered asynchronously", message);
 
+      GST_MINI_OBJECT_FLAG_UNSET (message, GST_MESSAGE_FLAG_ASYNC_DELIVERY);
+
       g_mutex_clear (lock);
       g_cond_clear (cond);
+
+      gst_message_unref (message);
       break;
     }
     default:
@@ -369,8 +406,8 @@ gst_bus_post (GstBus * bus, GstMessage * message)
 is_flushing:
   {
     GST_DEBUG_OBJECT (bus, "bus is flushing");
-    gst_message_unref (message);
     GST_OBJECT_UNLOCK (bus);
+    gst_message_unref (message);
 
     return FALSE;
   }
@@ -383,7 +420,7 @@ is_flushing:
  * Check if there are pending messages on the bus that
  * should be handled.
  *
- * Returns: TRUE if there are messages on the bus to be handled, FALSE
+ * Returns: %TRUE if there are messages on the bus to be handled, %FALSE
  * otherwise.
  *
  * MT safe.
@@ -396,7 +433,7 @@ gst_bus_have_pending (GstBus * bus)
   g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
 
   /* see if there is a message on the bus */
-  result = gst_atomic_queue_length (bus->queue) != 0;
+  result = gst_atomic_queue_length (bus->priv->queue) != 0;
 
   return result;
 }
@@ -408,7 +445,7 @@ gst_bus_have_pending (GstBus * bus)
  *
  * If @flushing, flush out and unref any messages queued in the bus. Releases
  * references to the message origin objects. Will flush future messages until
- * gst_bus_set_flushing() sets @flushing to #FALSE.
+ * gst_bus_set_flushing() sets @flushing to %FALSE.
  *
  * MT safe.
  */
@@ -416,6 +453,9 @@ void
 gst_bus_set_flushing (GstBus * bus, gboolean flushing)
 {
   GstMessage *message;
+  GList *message_list = NULL;
+
+  g_return_if_fail (GST_IS_BUS (bus));
 
   GST_OBJECT_LOCK (bus);
 
@@ -425,13 +465,15 @@ gst_bus_set_flushing (GstBus * bus, gboolean flushing)
     GST_DEBUG_OBJECT (bus, "set bus flushing");
 
     while ((message = gst_bus_pop (bus)))
-      gst_message_unref (message);
+      message_list = g_list_prepend (message_list, message);
   } else {
     GST_DEBUG_OBJECT (bus, "unset bus flushing");
     GST_OBJECT_FLAG_UNSET (bus, GST_BUS_FLUSHING);
   }
 
   GST_OBJECT_UNLOCK (bus);
+
+  g_list_free_full (message_list, (GDestroyNotify) gst_message_unref);
 }
 
 /**
@@ -448,14 +490,13 @@ gst_bus_set_flushing (GstBus * bus, gboolean flushing)
  * @timeout is #GST_CLOCK_TIME_NONE, this function will block forever until a
  * matching message was posted on the bus.
  *
- * Returns: (transfer full): a #GstMessage matching the filter in @types,
- *     or NULL if no matching message was found on the bus until the timeout
- *     expired. The message is taken from the bus and needs to be unreffed
- *     with gst_message_unref() after usage.
+ * Returns: (transfer full) (nullable): a #GstMessage matching the
+ *     filter in @types, or %NULL if no matching message was found on
+ *     the bus until the timeout expired. The message is taken from
+ *     the bus and needs to be unreffed with gst_message_unref() after
+ *     usage.
  *
  * MT safe.
- *
- * Since: 0.10.15
  */
 GstMessage *
 gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout,
@@ -470,29 +511,50 @@ gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout,
   g_return_val_if_fail (types != 0, NULL);
   g_return_val_if_fail (timeout == 0 || bus->priv->poll != NULL, NULL);
 
-  g_mutex_lock (&bus->queue_lock);
+  g_mutex_lock (&bus->priv->queue_lock);
 
   while (TRUE) {
     gint ret;
 
     GST_LOG_OBJECT (bus, "have %d messages",
-        gst_atomic_queue_length (bus->queue));
-
-    while ((message = gst_atomic_queue_pop (bus->queue))) {
-      if (bus->priv->poll)
-        gst_poll_read_control (bus->priv->poll);
+        gst_atomic_queue_length (bus->priv->queue));
+
+    while ((message = gst_atomic_queue_pop (bus->priv->queue))) {
+      if (bus->priv->poll) {
+        while (!gst_poll_read_control (bus->priv->poll)) {
+          if (errno == EWOULDBLOCK) {
+            /* Retry, this can happen if pushing to the queue has finished,
+             * popping here succeeded but writing control did not finish
+             * before we got to this line. */
+            /* Give other threads the chance to do something */
+            g_thread_yield ();
+            continue;
+          } else {
+            /* This is a real error and means that either the bus is in an
+             * inconsistent state, or the GstPoll is invalid. GstPoll already
+             * prints a critical warning about this, no need to do that again
+             * ourselves */
+            break;
+          }
+        }
+      }
 
       GST_DEBUG_OBJECT (bus, "got message %p, %s from %s, type mask is %u",
           message, GST_MESSAGE_TYPE_NAME (message),
           GST_MESSAGE_SRC_NAME (message), (guint) types);
       if ((GST_MESSAGE_TYPE (message) & types) != 0) {
-        /* exit the loop, we have a message */
-        goto beach;
-      } else {
-        GST_DEBUG_OBJECT (bus, "discarding message, does not match mask");
-        gst_message_unref (message);
-        message = NULL;
+        /* Extra check to ensure extended types don't get matched unless
+         * asked for */
+        if ((!GST_MESSAGE_TYPE_IS_EXTENDED (message))
+            || (types & GST_MESSAGE_EXTENDED)) {
+          /* exit the loop, we have a message */
+          goto beach;
+        }
       }
+
+      GST_DEBUG_OBJECT (bus, "discarding message, does not match mask");
+      gst_message_unref (message);
+      message = NULL;
     }
 
     /* no need to wait, exit loop */
@@ -515,9 +577,9 @@ gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout,
 
     /* only here in timeout case */
     g_assert (bus->priv->poll);
-    g_mutex_unlock (&bus->queue_lock);
+    g_mutex_unlock (&bus->priv->queue_lock);
     ret = gst_poll_wait (bus->priv->poll, timeout - elapsed);
-    g_mutex_lock (&bus->queue_lock);
+    g_mutex_lock (&bus->priv->queue_lock);
 
     if (ret == 0) {
       GST_INFO_OBJECT (bus, "timed out, breaking loop");
@@ -529,7 +591,7 @@ gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout,
 
 beach:
 
-  g_mutex_unlock (&bus->queue_lock);
+  g_mutex_unlock (&bus->priv->queue_lock);
 
   return message;
 }
@@ -546,14 +608,12 @@ beach:
  * #GST_CLOCK_TIME_NONE, this function will block forever until a message was
  * posted on the bus.
  *
- * Returns: (transfer full): the #GstMessage that is on the bus after the
- *     specified timeout or NULL if the bus is empty after the timeout expired.
- * The message is taken from the bus and needs to be unreffed with
- * gst_message_unref() after usage.
+ * Returns: (transfer full) (nullable): the #GstMessage that is on the
+ *     bus after the specified timeout or %NULL if the bus is empty
+ *     after the timeout expired.  The message is taken from the bus
+ *     and needs to be unreffed with gst_message_unref() after usage.
  *
  * MT safe.
- *
- * Since: 0.10.12
  */
 GstMessage *
 gst_bus_timed_pop (GstBus * bus, GstClockTime timeout)
@@ -571,16 +631,15 @@ gst_bus_timed_pop (GstBus * bus, GstClockTime timeout)
  * Get a message matching @type from the bus.  Will discard all messages on
  * the bus that do not match @type and that have been posted before the first
  * message that does match @type.  If there is no message matching @type on
- * the bus, all messages will be discarded.
+ * the bus, all messages will be discarded. It is not possible to use message
+ * enums beyond #GST_MESSAGE_EXTENDED in the @events mask.
  *
- * Returns: (transfer full): the next #GstMessage matching @type that is on
- *     the bus, or NULL if the bus is empty or there is no message matching
- *     @type. The message is taken from the bus and needs to be unreffed with
- *     gst_message_unref() after usage.
+ * Returns: (transfer full) (nullable): the next #GstMessage matching
+ *     @type that is on the bus, or %NULL if the bus is empty or there
+ *     is no message matching @type. The message is taken from the bus
+ *     and needs to be unreffed with gst_message_unref() after usage.
  *
  * MT safe.
- *
- * Since: 0.10.15
  */
 GstMessage *
 gst_bus_pop_filtered (GstBus * bus, GstMessageType types)
@@ -597,9 +656,10 @@ gst_bus_pop_filtered (GstBus * bus, GstMessageType types)
  *
  * Get a message from the bus.
  *
- * Returns: (transfer full): the #GstMessage that is on the bus, or NULL if the
- *     bus is empty. The message is taken from the bus and needs to be unreffed
- *     with gst_message_unref() after usage.
+ * Returns: (transfer full) (nullable): the #GstMessage that is on the
+ *     bus, or %NULL if the bus is empty. The message is taken from
+ *     the bus and needs to be unreffed with gst_message_unref() after
+ *     usage.
  *
  * MT safe.
  */
@@ -619,8 +679,8 @@ gst_bus_pop (GstBus * bus)
  * on the bus' message queue. A reference is returned, and needs to be unreffed
  * by the caller.
  *
- * Returns: (transfer full): the #GstMessage that is on the bus, or NULL if the
- *     bus is empty.
+ * Returns: (transfer full) (nullable): the #GstMessage that is on the
+ *     bus, or %NULL if the bus is empty.
  *
  * MT safe.
  */
@@ -631,11 +691,11 @@ gst_bus_peek (GstBus * bus)
 
   g_return_val_if_fail (GST_IS_BUS (bus), NULL);
 
-  g_mutex_lock (&bus->queue_lock);
-  message = gst_atomic_queue_peek (bus->queue);
+  g_mutex_lock (&bus->priv->queue_lock);
+  message = gst_atomic_queue_peek (bus->priv->queue);
   if (message)
     gst_message_ref (message);
-  g_mutex_unlock (&bus->queue_lock);
+  g_mutex_unlock (&bus->priv->queue_lock);
 
   GST_DEBUG_OBJECT (bus, "peek on bus, got message %p", message);
 
@@ -645,8 +705,9 @@ gst_bus_peek (GstBus * bus)
 /**
  * gst_bus_set_sync_handler:
  * @bus: a #GstBus to install the handler on
- * @func: The handler function to install
- * @data: User data that will be sent to the handler function.
+ * @func: (allow-none): The handler function to install
+ * @user_data: User data that will be sent to the handler function.
+ * @notify: called when @user_data becomes unused
  *
  * Sets the synchronous handler on the bus. The function will be called
  * every time a new message is posted on the bus. Note that the function
@@ -655,23 +716,37 @@ gst_bus_peek (GstBus * bus)
  * should handle messages asynchronously using the gst_bus watch and poll
  * functions.
  *
- * You cannot replace an existing sync_handler. You can pass NULL to this
+ * You cannot replace an existing sync_handler. You can pass %NULL to this
  * function, which will clear the existing handler.
  */
 void
-gst_bus_set_sync_handler (GstBus * bus, GstBusSyncHandler func, gpointer data)
+gst_bus_set_sync_handler (GstBus * bus, GstBusSyncHandler func,
+    gpointer user_data, GDestroyNotify notify)
 {
+  GDestroyNotify old_notify;
+
   g_return_if_fail (GST_IS_BUS (bus));
 
   GST_OBJECT_LOCK (bus);
-
   /* Assert if the user attempts to replace an existing sync_handler,
    * other than to clear it */
-  if (func != NULL && bus->sync_handler != NULL)
+  if (func != NULL && bus->priv->sync_handler != NULL)
     goto no_replace;
 
-  bus->sync_handler = func;
-  bus->sync_handler_data = data;
+  if ((old_notify = bus->priv->sync_handler_notify)) {
+    gpointer old_data = bus->priv->sync_handler_data;
+
+    bus->priv->sync_handler_data = NULL;
+    bus->priv->sync_handler_notify = NULL;
+    GST_OBJECT_UNLOCK (bus);
+
+    old_notify (old_data);
+
+    GST_OBJECT_LOCK (bus);
+  }
+  bus->priv->sync_handler = func;
+  bus->priv->sync_handler_data = user_data;
+  bus->priv->sync_handler_notify = notify;
   GST_OBJECT_UNLOCK (bus);
 
   return;
@@ -684,6 +759,31 @@ no_replace:
   }
 }
 
+/**
+ * gst_bus_get_pollfd:
+ * @bus: A #GstBus
+ * @fd: (out): A GPollFD to fill
+ *
+ * Gets the file descriptor from the bus which can be used to get notified about
+ * messages being available with functions like g_poll(), and allows integration
+ * into other event loops based on file descriptors.
+ * Whenever a message is available, the POLLIN / %G_IO_IN event is set.
+ *
+ * Warning: NEVER read or write anything to the returned fd but only use it
+ * for getting notifications via g_poll() or similar and then use the normal
+ * GstBus API, e.g. gst_bus_pop().
+ *
+ * Since: 1.14
+ */
+void
+gst_bus_get_pollfd (GstBus * bus, GPollFD * fd)
+{
+  g_return_if_fail (GST_IS_BUS (bus));
+  g_return_if_fail (bus->priv->poll != NULL);
+
+  *fd = bus->priv->pollfd;
+}
+
 /* GSource for the bus
  */
 typedef struct
@@ -763,8 +863,8 @@ gst_bus_source_finalize (GSource * source)
   GST_DEBUG_OBJECT (bus, "finalize source %p", source);
 
   GST_OBJECT_LOCK (bus);
-  if (bus->priv->watch_id == source)
-    bus->priv->watch_id = NULL;
+  if (bus->priv->signal_watch == source)
+    bus->priv->signal_watch = NULL;
   GST_OBJECT_UNLOCK (bus);
 
   gst_object_unref (bsource->bus);
@@ -786,7 +886,7 @@ static GSourceFuncs gst_bus_source_funcs = {
  * a message is on the bus. After the GSource is dispatched, the
  * message is popped off the bus and unreffed.
  *
- * Returns: (transfer full): a #GSource that can be added to a mainloop.
+ * Returns: (transfer full) (nullable): a #GSource that can be added to a mainloop.
  */
 GSource *
 gst_bus_create_watch (GstBus * bus)
@@ -816,13 +916,17 @@ gst_bus_add_watch_full_unlocked (GstBus * bus, gint priority,
   guint id;
   GSource *source;
 
-  if (bus->priv->watch_id) {
+  if (bus->priv->signal_watch) {
     GST_ERROR_OBJECT (bus,
         "Tried to add new watch while one was already there");
     return 0;
   }
 
   source = gst_bus_create_watch (bus);
+  if (!source) {
+    g_critical ("Creating bus watch failed");
+    return 0;
+  }
 
   if (priority != G_PRIORITY_DEFAULT)
     g_source_set_priority (source, priority);
@@ -834,7 +938,7 @@ gst_bus_add_watch_full_unlocked (GstBus * bus, gint priority,
   g_source_unref (source);
 
   if (id) {
-    bus->priv->watch_id = source;
+    bus->priv->signal_watch = source;
   }
 
   GST_DEBUG_OBJECT (bus, "New source %p with id %u", source, id);
@@ -842,7 +946,7 @@ gst_bus_add_watch_full_unlocked (GstBus * bus, gint priority,
 }
 
 /**
- * gst_bus_add_watch_full:
+ * gst_bus_add_watch_full: (rename-to gst_bus_add_watch)
  * @bus: a #GstBus to create the watch for.
  * @priority: The priority of the watch.
  * @func: A function to call when a message is received.
@@ -850,8 +954,8 @@ gst_bus_add_watch_full_unlocked (GstBus * bus, gint priority,
  * @notify: the function to call when the source is removed.
  *
  * Adds a bus watch to the default main context with the given @priority (e.g.
- * %G_PRIORITY_DEFAULT). Since 0.10.33 it is also possible to use a non-default
- * main context set up using g_main_context_push_thread_default() (before
+ * %G_PRIORITY_DEFAULT). It is also possible to use a non-default  main
+ * context set up using g_main_context_push_thread_default() (before
  * one had to create a bus watch source and attach it to the desired main
  * context 'manually').
  *
@@ -859,15 +963,21 @@ gst_bus_add_watch_full_unlocked (GstBus * bus, gint priority,
  * There can only be a single bus watch per bus, you must remove it before you
  * can set a new one.
  *
+ * The bus watch will only work if a GLib main loop is being run.
+ *
  * When @func is called, the message belongs to the caller; if you want to
  * keep a copy of it, call gst_message_ref() before leaving @func.
  *
- * The watch can be removed using g_source_remove() or by returning FALSE
- * from @func.
+ * The watch can be removed using gst_bus_remove_watch() or by returning %FALSE
+ * from @func. If the watch was added to the default main context it is also
+ * possible to remove the watch using g_source_remove().
+ *
+ * The bus watch will take its own reference to the @bus, so it is safe to unref
+ * @bus using gst_object_unref() after setting the bus watch.
  *
- * Returns: The event source id.
- * Rename to: gst_bus_add_watch
  * MT safe.
+ *
+ * Returns: The event source id or 0 if @bus already got an event source.
  */
 guint
 gst_bus_add_watch_full (GstBus * bus, gint priority,
@@ -891,8 +1001,8 @@ gst_bus_add_watch_full (GstBus * bus, gint priority,
  * @user_data: user data passed to @func.
  *
  * Adds a bus watch to the default main context with the default priority
- * (%G_PRIORITY_DEFAULT). Since 0.10.33 it is also possible to use a non-default
- * main context set up using g_main_context_push_thread_default() (before
+ * (%G_PRIORITY_DEFAULT). It is also possible to use a non-default main
+ * context set up using g_main_context_push_thread_default() (before
  * one had to create a bus watch source and attach it to the desired main
  * context 'manually').
  *
@@ -900,12 +1010,18 @@ gst_bus_add_watch_full (GstBus * bus, gint priority,
  * There can only be a single bus watch per bus, you must remove it before you
  * can set a new one.
  *
- * The watch can be removed using g_source_remove() or by returning FALSE
- * from @func.
+ * The bus watch will only work if a GLib main loop is being run.
+ *
+ * The watch can be removed using gst_bus_remove_watch() or by returning %FALSE
+ * from @func. If the watch was added to the default main context it is also
+ * possible to remove the watch using g_source_remove().
  *
- * Returns: The event source id.
+ * The bus watch will take its own reference to the @bus, so it is safe to unref
+ * @bus using gst_object_unref() after setting the bus watch.
  *
  * MT safe.
+ *
+ * Returns: The event source id or 0 if @bus already got an event source.
  */
 guint
 gst_bus_add_watch (GstBus * bus, GstBusFunc func, gpointer user_data)
@@ -914,6 +1030,55 @@ gst_bus_add_watch (GstBus * bus, GstBusFunc func, gpointer user_data)
       user_data, NULL);
 }
 
+/**
+ * gst_bus_remove_watch:
+ * @bus: a #GstBus to remove the watch from.
+ *
+ * Removes an installed bus watch from @bus.
+ *
+ * Returns: %TRUE on success or %FALSE if @bus has no event source.
+ *
+ * Since: 1.6
+ *
+ */
+gboolean
+gst_bus_remove_watch (GstBus * bus)
+{
+  GSource *source;
+
+  g_return_val_if_fail (GST_IS_BUS (bus), FALSE);
+
+  GST_OBJECT_LOCK (bus);
+
+  if (bus->priv->signal_watch == NULL) {
+    GST_ERROR_OBJECT (bus, "no bus watch was present");
+    goto error;
+  }
+
+  if (bus->priv->num_signal_watchers > 0) {
+    GST_ERROR_OBJECT (bus,
+        "trying to remove signal watch with gst_bus_remove_watch()");
+    goto error;
+  }
+
+  source =
+      bus->priv->signal_watch ? g_source_ref (bus->priv->signal_watch) : NULL;
+
+  GST_OBJECT_UNLOCK (bus);
+
+  if (source) {
+    g_source_destroy (source);
+    g_source_unref (source);
+  }
+
+  return TRUE;
+
+error:
+  GST_OBJECT_UNLOCK (bus);
+
+  return FALSE;
+}
+
 typedef struct
 {
   GMainLoop *loop;
@@ -981,8 +1146,8 @@ poll_destroy_timeout (GstBusPollData * poll_data)
  * gst_bus_poll:
  * @bus: a #GstBus
  * @events: a mask of #GstMessageType, representing the set of message types to
- * poll for.
- * @timeout: the poll timeout, as a #GstClockTimeDiff, or -1 to poll
+ * poll for (note special handling of extended message types below)
+ * @timeout: the poll timeout, as a #GstClockTime, or #GST_CLOCK_TIME_NONE to poll
  * indefinitely.
  *
  * Poll the bus for messages. Will block while waiting for messages to come.
@@ -990,6 +1155,8 @@ poll_destroy_timeout (GstBusPollData * poll_data)
  * @timeout is negative, this function will block indefinitely.
  *
  * All messages not in @events will be popped off the bus and will be ignored.
+ * It is not possible to use message enums beyond #GST_MESSAGE_EXTENDED in the
+ * @events mask
  *
  * Because poll is implemented using the "message" signal enabled by
  * gst_bus_add_signal_watch(), calling gst_bus_poll() will cause the "message"
@@ -1017,24 +1184,27 @@ poll_destroy_timeout (GstBusPollData * poll_data)
  * better handled by setting up an asynchronous bus watch and doing things
  * from there.
  *
- * Returns: (transfer full): the message that was received, or NULL if the
- *     poll timed out. The message is taken from the bus and needs to be
- *     unreffed with gst_message_unref() after usage.
+ * Returns: (transfer full) (nullable): the message that was received,
+ *     or %NULL if the poll timed out. The message is taken from the
+ *     bus and needs to be unreffed with gst_message_unref() after
+ *     usage.
  */
 GstMessage *
-gst_bus_poll (GstBus * bus, GstMessageType events, GstClockTimeDiff timeout)
+gst_bus_poll (GstBus * bus, GstMessageType events, GstClockTime timeout)
 {
   GstBusPollData *poll_data;
   GstMessage *ret;
   gulong id;
 
+  g_return_val_if_fail (GST_IS_BUS (bus), NULL);
+
   poll_data = g_slice_new (GstBusPollData);
   poll_data->source_running = TRUE;
   poll_data->loop = g_main_loop_new (NULL, FALSE);
   poll_data->events = events;
   poll_data->message = NULL;
 
-  if (timeout >= 0)
+  if (timeout != GST_CLOCK_TIME_NONE)
     poll_data->timeout_id = g_timeout_add_full (G_PRIORITY_DEFAULT_IDLE,
         timeout / GST_MSECOND, (GSourceFunc) poll_timeout, poll_data,
         (GDestroyNotify) poll_destroy_timeout);
@@ -1076,7 +1246,7 @@ gst_bus_poll (GstBus * bus, GstMessageType events, GstClockTimeDiff timeout)
  * A helper #GstBusFunc that can be used to convert all asynchronous messages
  * into signals.
  *
- * Returns: TRUE
+ * Returns: %TRUE
  */
 gboolean
 gst_bus_async_signal_func (GstBus * bus, GstMessage * message, gpointer data)
@@ -1173,7 +1343,7 @@ void
 gst_bus_disable_sync_message_emission (GstBus * bus)
 {
   g_return_if_fail (GST_IS_BUS (bus));
-  g_return_if_fail (bus->num_signal_watchers == 0);
+  g_return_if_fail (bus->priv->num_sync_message_emitters > 0);
 
   GST_OBJECT_LOCK (bus);
   bus->priv->num_sync_message_emitters--;
@@ -1186,8 +1356,8 @@ gst_bus_disable_sync_message_emission (GstBus * bus)
  * @priority: The priority of the watch.
  *
  * Adds a bus signal watch to the default main context with the given @priority
- * (e.g. %G_PRIORITY_DEFAULT). Since 0.10.33 it is also possible to use a
- * non-default main context set up using g_main_context_push_thread_default()
+ * (e.g. %G_PRIORITY_DEFAULT). It is also possible to use a non-default main
+ * context set up using g_main_context_push_thread_default()
  * (before one had to create a bus watch source and attach it to the desired
  * main context 'manually').
  *
@@ -1211,22 +1381,21 @@ gst_bus_add_signal_watch_full (GstBus * bus, gint priority)
   /* I know the callees don't take this lock, so go ahead and abuse it */
   GST_OBJECT_LOCK (bus);
 
-  if (bus->num_signal_watchers > 0)
+  if (bus->priv->num_signal_watchers > 0)
     goto done;
 
   /* this should not fail because the counter above takes care of it */
-  g_assert (bus->signal_watch_id == 0);
+  g_assert (!bus->priv->signal_watch);
 
-  bus->signal_watch_id =
-      gst_bus_add_watch_full_unlocked (bus, priority, gst_bus_async_signal_func,
+  gst_bus_add_watch_full_unlocked (bus, priority, gst_bus_async_signal_func,
       NULL, NULL);
 
-  if (G_UNLIKELY (bus->signal_watch_id == 0))
+  if (G_UNLIKELY (!bus->priv->signal_watch))
     goto add_failed;
 
 done:
 
-  bus->num_signal_watchers++;
+  bus->priv->num_signal_watchers++;
 
   GST_OBJECT_UNLOCK (bus);
   return;
@@ -1245,7 +1414,7 @@ add_failed:
  * @bus: a #GstBus on which you want to receive the "message" signal
  *
  * Adds a bus signal watch to the default main context with the default priority
- * (%G_PRIORITY_DEFAULT). Since 0.10.33 it is also possible to use a non-default
+ * (%G_PRIORITY_DEFAULT). It is also possible to use a non-default
  * main context set up using g_main_context_push_thread_default() (before
  * one had to create a bus watch source and attach it to the desired main
  * context 'manually').
@@ -1276,31 +1445,34 @@ gst_bus_add_signal_watch (GstBus * bus)
 void
 gst_bus_remove_signal_watch (GstBus * bus)
 {
-  guint id = 0;
+  GSource *source = NULL;
 
   g_return_if_fail (GST_IS_BUS (bus));
 
   /* I know the callees don't take this lock, so go ahead and abuse it */
   GST_OBJECT_LOCK (bus);
 
-  if (bus->num_signal_watchers == 0)
+  if (bus->priv->num_signal_watchers == 0)
     goto error;
 
-  bus->num_signal_watchers--;
+  bus->priv->num_signal_watchers--;
 
-  if (bus->num_signal_watchers > 0)
+  if (bus->priv->num_signal_watchers > 0)
     goto done;
 
-  id = bus->signal_watch_id;
-  bus->signal_watch_id = 0;
+  GST_DEBUG_OBJECT (bus, "removing signal watch %u",
+      g_source_get_id (bus->priv->signal_watch));
 
-  GST_DEBUG_OBJECT (bus, "removing signal watch %u", id);
+  source =
+      bus->priv->signal_watch ? g_source_ref (bus->priv->signal_watch) : NULL;
 
 done:
   GST_OBJECT_UNLOCK (bus);
 
-  if (id)
-    g_source_remove (id);
+  if (source) {
+    g_source_destroy (source);
+    g_source_unref (source);
+  }
 
   return;