/**
* SECTION:gstbus
+ * @title: GstBus
* @short_description: Asynchronous message bus subsystem
* @see_also: #GstMessage, #GstElement
*
*
* Note that a #GstPipeline will set its bus into flushing state when changing
* from READY to NULL state.
- *
- * Last reviewed on 2012-03-28 (0.11.3)
*/
#include "gst_private.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
gpointer sync_handler_data;
GDestroyNotify sync_handler_notify;
- guint signal_watch_id;
guint num_signal_watchers;
guint num_sync_message_emitters;
- GSource *watch_id;
+ GSource *signal_watch;
gboolean enable_async;
GstPoll *poll;
};
#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,
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
G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
G_STRUCT_OFFSET (GstBusClass, message), NULL, NULL,
g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_MESSAGE);
-
- g_type_class_add_private (klass, sizeof (GstBusPrivate));
}
static void
gst_bus_init (GstBus * bus)
{
- 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);
- /* clear floating flag */
- gst_object_ref_sink (bus);
-
GST_DEBUG_OBJECT (bus, "created");
}
{
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;
}
* 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.
*/
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))
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
/* 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:
is_flushing:
{
GST_DEBUG_OBJECT (bus, "bus is flushing");
- gst_message_unref (message);
GST_OBJECT_UNLOCK (bus);
+ gst_message_unref (message);
return FALSE;
}
* 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.
*
* 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.
*/
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);
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);
}
/**
* @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.
*/
gst_atomic_queue_length (bus->priv->queue));
while ((message = gst_atomic_queue_pop (bus->priv->queue))) {
- if (bus->priv->poll)
- gst_poll_read_control (bus->priv->poll);
+ 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 */
* #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.
*/
* 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.
*/
*
* 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.
*/
* 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.
*/
* 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_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
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);
* 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)
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);
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);
}
/**
- * 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.
* 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.
*
* MT safe.
*
- * Returns: The event source id.
- * Rename to: gst_bus_add_watch
+ * Returns: The event source id or 0 if @bus already got an event source.
*/
guint
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.
*
- * Returns: The event source id.
+ * 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.
*
* 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)
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 *watch_id;
+
+ 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 no_watch;
+ }
+
+ watch_id = bus->priv->signal_watch;
+
+ GST_OBJECT_UNLOCK (bus);
+
+ g_source_destroy (watch_id);
+
+ return TRUE;
+
+no_watch:
+ GST_OBJECT_UNLOCK (bus);
+
+ return FALSE;
+}
+
typedef struct
{
GMainLoop *loop;
* gst_bus_poll:
* @bus: a #GstBus
* @events: a mask of #GstMessageType, representing the set of message types to
- * poll for.
+ * 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.
*
* @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"
* 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, GstClockTime timeout)
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);
* 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)
gst_bus_disable_sync_message_emission (GstBus * bus)
{
g_return_if_fail (GST_IS_BUS (bus));
- g_return_if_fail (bus->priv->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--;
goto done;
/* this should not fail because the counter above takes care of it */
- g_assert (bus->priv->signal_watch_id == 0);
+ g_assert (!bus->priv->signal_watch);
- bus->priv->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->priv->signal_watch_id == 0))
+ if (G_UNLIKELY (!bus->priv->signal_watch))
goto add_failed;
done:
void
gst_bus_remove_signal_watch (GstBus * bus)
{
- guint id = 0;
+ GSource *source = NULL;
g_return_if_fail (GST_IS_BUS (bus));
if (bus->priv->num_signal_watchers > 0)
goto done;
- id = bus->priv->signal_watch_id;
- bus->priv->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;
done:
GST_OBJECT_UNLOCK (bus);
- if (id)
- g_source_remove (id);
+ if (source)
+ g_source_destroy (source);
return;