3 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
4 * 2004 Wim Taymans <wim.taymans@gmail.com>
6 * gstbin.c: GstBin container object and support code
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
28 * @short_description: Base class and element that can contain other elements
30 * #GstBin is an element that can contain other #GstElement, allowing them to be
32 * Pads from the child elements can be ghosted to the bin, see #GstGhostPad.
33 * This makes the bin look like any other elements and enables creation of
34 * higher-level abstraction elements.
36 * A new #GstBin is created with gst_bin_new(). Use a #GstPipeline instead if you
37 * want to create a toplevel bin because a normal bin doesn't have a bus or
38 * handle clock distribution of its own.
40 * After the bin has been created you will typically add elements to it with
41 * gst_bin_add(). You can remove elements with gst_bin_remove().
43 * An element can be retrieved from a bin with gst_bin_get_by_name(), using the
44 * elements name. gst_bin_get_by_name_recurse_up() is mainly used for internal
45 * purposes and will query the parent bins when the element is not found in the
48 * An iterator of elements in a bin can be retrieved with
49 * gst_bin_iterate_elements(). Various other iterators exist to retrieve the
52 * gst_object_unref() is used to drop your reference to the bin.
54 * The #GstBin::element-added signal is fired whenever a new element is added to
55 * the bin. Likewise the #GstBin::element-removed signal is fired whenever an
56 * element is removed from the bin.
58 * <refsect2><title>Notes</title>
60 * A #GstBin internally intercepts every #GstMessage posted by its children and
61 * implements the following default behaviour for each of them:
64 * <term>GST_MESSAGE_EOS</term>
65 * <listitem><para>This message is only posted by sinks in the PLAYING
66 * state. If all sinks posted the EOS message, this bin will post and EOS
67 * message upwards.</para></listitem>
70 * <term>GST_MESSAGE_SEGMENT_START</term>
71 * <listitem><para>just collected and never forwarded upwards.
72 * The messages are used to decide when all elements have completed playback
73 * of their segment.</para></listitem>
76 * <term>GST_MESSAGE_SEGMENT_DONE</term>
77 * <listitem><para> Is posted by #GstBin when all elements that posted
78 * a SEGMENT_START have posted a SEGMENT_DONE.</para></listitem>
81 * <term>GST_MESSAGE_DURATION</term>
82 * <listitem><para> Is posted by an element that detected a change
83 * in the stream duration. The default bin behaviour is to clear any
84 * cached duration values so that the next duration query will perform
85 * a full duration recalculation. The duration change is posted to the
86 * application so that it can refetch the new duration with a duration
87 * query. Note that these messages can be posted before the bin is
88 * prerolled, in which case the duration query might fail.
92 * <term>GST_MESSAGE_CLOCK_LOST</term>
93 * <listitem><para> This message is posted by an element when it
94 * can no longer provide a clock. The default bin behaviour is to
95 * check if the lost clock was the one provided by the bin. If so and
96 * the bin is currently in the PLAYING state, the message is forwarded to
98 * This message is also generated when a clock provider is removed from
99 * the bin. If this message is received by the application, it should
100 * PAUSE the pipeline and set it back to PLAYING to force a new clock
105 * <term>GST_MESSAGE_CLOCK_PROVIDE</term>
106 * <listitem><para> This message is generated when an element
107 * can provide a clock. This mostly happens when a new clock
108 * provider is added to the bin. The default behaviour of the bin is to
109 * mark the currently selected clock as dirty, which will perform a clock
110 * recalculation the next time the bin is asked to provide a clock.
111 * This message is never sent tot the application but is forwarded to
112 * the parent of the bin.
116 * <term>OTHERS</term>
117 * <listitem><para> posted upwards.</para></listitem>
122 * A #GstBin implements the following default behaviour for answering to a
126 * <term>GST_QUERY_DURATION</term>
127 * <listitem><para>If the query has been asked before with the same format
128 * and the bin is a toplevel bin (ie. has no parent),
129 * use the cached previous value. If no previous value was cached, the
130 * query is sent to all sink elements in the bin and the MAXIMUM of all
131 * values is returned. If the bin is a toplevel bin the value is cached.
132 * If no sinks are available in the bin, the query fails.
136 * <term>GST_QUERY_POSITION</term>
137 * <listitem><para>The query is sent to all sink elements in the bin and the
138 * MAXIMUM of all values is returned. If no sinks are available in the bin,
143 * <term>OTHERS</term>
144 * <listitem><para>the query is forwarded to all sink elements, the result
145 * of the first sink that answers the query successfully is returned. If no
146 * sink is in the bin, the query fails.</para></listitem>
150 * A #GstBin will by default forward any event sent to it to all sink elements.
151 * If all the sinks return TRUE, the bin will also return TRUE, else FALSE is
152 * returned. If no sinks are in the bin, the event handler will return TRUE.
157 * Last reviewed on 2012-03-28 (0.11.3)
160 #include "gst_private.h"
162 #include "gstevent.h"
165 #include "gsterror.h"
167 #include "gstutils.h"
168 #include "gstchildproxy.h"
170 GST_DEBUG_CATEGORY_STATIC (bin_debug);
171 #define GST_CAT_DEFAULT bin_debug
173 /* a bin is toplevel if it has no parent or when it is configured to behave like
175 #define BIN_IS_TOPLEVEL(bin) ((GST_OBJECT_PARENT (bin) == NULL) || bin->priv->asynchandling)
177 #define GST_BIN_GET_PRIVATE(obj) \
178 (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_BIN, GstBinPrivate))
180 struct _GstBinPrivate
182 gboolean asynchandling;
183 /* if we get an ASYNC_DONE message from ourselves, this means that the
184 * subclass will simulate ASYNC behaviour without having ASYNC children. When
185 * such an ASYNC_DONE message is posted while we are doing a state change, we
186 * have to process the message after finishing the state change even when no
187 * child returned GST_STATE_CHANGE_ASYNC. */
188 gboolean pending_async_done;
190 guint32 structure_cookie;
197 /* forward messages from our children */
198 gboolean message_forward;
210 static void gst_bin_dispose (GObject * object);
212 static void gst_bin_set_property (GObject * object, guint prop_id,
213 const GValue * value, GParamSpec * pspec);
214 static void gst_bin_get_property (GObject * object, guint prop_id,
215 GValue * value, GParamSpec * pspec);
217 static GstStateChangeReturn gst_bin_change_state_func (GstElement * element,
218 GstStateChange transition);
219 static void gst_bin_state_changed (GstElement * element, GstState oldstate,
220 GstState newstate, GstState pending);
221 static GstStateChangeReturn gst_bin_get_state_func (GstElement * element,
222 GstState * state, GstState * pending, GstClockTime timeout);
223 static void bin_handle_async_done (GstBin * bin, GstStateChangeReturn ret,
224 gboolean flag_pending, GstClockTime running_time);
225 static void bin_handle_async_start (GstBin * bin);
226 static void bin_push_state_continue (BinContinueData * data);
227 static void bin_do_eos (GstBin * bin);
229 static gboolean gst_bin_add_func (GstBin * bin, GstElement * element);
230 static gboolean gst_bin_remove_func (GstBin * bin, GstElement * element);
233 static void gst_bin_set_index_func (GstElement * element, GstIndex * index);
234 static GstIndex *gst_bin_get_index_func (GstElement * element);
237 static GstClock *gst_bin_provide_clock_func (GstElement * element);
238 static gboolean gst_bin_set_clock_func (GstElement * element, GstClock * clock);
240 static void gst_bin_handle_message_func (GstBin * bin, GstMessage * message);
241 static gboolean gst_bin_send_event (GstElement * element, GstEvent * event);
242 static GstBusSyncReply bin_bus_handler (GstBus * bus,
243 GstMessage * message, GstBin * bin);
244 static gboolean gst_bin_query (GstElement * element, GstQuery * query);
246 static gboolean gst_bin_do_latency_func (GstBin * bin);
248 static void bin_remove_messages (GstBin * bin, GstObject * src,
249 GstMessageType types);
250 static void gst_bin_continue_func (BinContinueData * data);
251 static gint bin_element_is_sink (GstElement * child, GstBin * bin);
252 static gint bin_element_is_src (GstElement * child, GstBin * bin);
254 static GstIterator *gst_bin_sort_iterator_new (GstBin * bin);
256 /* Bin signals and properties */
265 #define DEFAULT_ASYNC_HANDLING FALSE
266 #define DEFAULT_MESSAGE_FORWARD FALSE
272 PROP_MESSAGE_FORWARD,
276 static void gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data);
278 static guint gst_bin_signals[LAST_SIGNAL] = { 0 };
282 static const GInterfaceInfo iface_info = { \
283 gst_bin_child_proxy_init, \
287 g_type_add_interface_static (g_define_type_id, GST_TYPE_CHILD_PROXY, &iface_info); \
289 GST_DEBUG_CATEGORY_INIT (bin_debug, "bin", GST_DEBUG_BOLD, \
290 "debugging info for the 'bin' container element"); \
294 #define gst_bin_parent_class parent_class
295 G_DEFINE_TYPE_WITH_CODE (GstBin, gst_bin, GST_TYPE_ELEMENT, _do_init);
298 gst_bin_child_proxy_get_child_by_index (GstChildProxy * child_proxy,
304 bin = GST_BIN_CAST (child_proxy);
306 GST_OBJECT_LOCK (bin);
307 if ((res = g_list_nth_data (bin->children, index)))
308 gst_object_ref (res);
309 GST_OBJECT_UNLOCK (bin);
311 return (GObject *) res;
315 gst_bin_child_proxy_get_children_count (GstChildProxy * child_proxy)
320 bin = GST_BIN_CAST (child_proxy);
322 GST_OBJECT_LOCK (bin);
323 num = bin->numchildren;
324 GST_OBJECT_UNLOCK (bin);
330 gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data)
332 GstChildProxyInterface *iface = g_iface;
334 iface->get_children_count = gst_bin_child_proxy_get_children_count;
335 iface->get_child_by_index = gst_bin_child_proxy_get_child_by_index;
339 _gst_boolean_accumulator (GSignalInvocationHint * ihint,
340 GValue * return_accu, const GValue * handler_return, gpointer dummy)
344 myboolean = g_value_get_boolean (handler_return);
345 if (!(ihint->run_type & G_SIGNAL_RUN_CLEANUP))
346 g_value_set_boolean (return_accu, myboolean);
348 GST_DEBUG ("invocation %d, %d", ihint->run_type, myboolean);
355 gst_bin_class_init (GstBinClass * klass)
357 GObjectClass *gobject_class;
358 GstElementClass *gstelement_class;
361 gobject_class = (GObjectClass *) klass;
362 gstelement_class = (GstElementClass *) klass;
364 g_type_class_add_private (klass, sizeof (GstBinPrivate));
366 gobject_class->set_property = gst_bin_set_property;
367 gobject_class->get_property = gst_bin_get_property;
370 * GstBin:async-handling:
372 * If set to #TRUE, the bin will handle asynchronous state changes.
373 * This should be used only if the bin subclass is modifying the state
374 * of its children on its own.
378 g_object_class_install_property (gobject_class, PROP_ASYNC_HANDLING,
379 g_param_spec_boolean ("async-handling", "Async Handling",
380 "The bin will handle Asynchronous state changes",
381 DEFAULT_ASYNC_HANDLING, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
384 * GstBin::element-added:
386 * @element: the #GstElement that was added to the bin
388 * Will be emitted after the element was added to the bin.
390 gst_bin_signals[ELEMENT_ADDED] =
391 g_signal_new ("element-added", G_TYPE_FROM_CLASS (klass),
392 G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_added), NULL,
393 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
395 * GstBin::element-removed:
397 * @element: the #GstElement that was removed from the bin
399 * Will be emitted after the element was removed from the bin.
401 gst_bin_signals[ELEMENT_REMOVED] =
402 g_signal_new ("element-removed", G_TYPE_FROM_CLASS (klass),
403 G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_removed), NULL,
404 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
406 * GstBin::do-latency:
409 * Will be emitted when the bin needs to perform latency calculations. This
410 * signal is only emited for toplevel bins or when async-handling is
413 * Only one signal handler is invoked. If no signals are connected, the
414 * default handler is invoked, which will query and distribute the lowest
415 * possible latency to all sinks.
417 * Connect to this signal if the default latency calculations are not
418 * sufficient, like when you need different latencies for different sinks in
423 gst_bin_signals[DO_LATENCY] =
424 g_signal_new ("do-latency", G_TYPE_FROM_CLASS (klass),
425 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstBinClass, do_latency),
426 _gst_boolean_accumulator, NULL, g_cclosure_marshal_generic,
427 G_TYPE_BOOLEAN, 0, G_TYPE_NONE);
430 * GstBin:message-forward:
432 * Forward all children messages, even those that would normally be filtered by
433 * the bin. This can be interesting when one wants to be notified of the EOS
434 * state of individual elements, for example.
436 * The messages are converted to an ELEMENT message with the bin as the
437 * source. The structure of the message is named 'GstBinForwarded' and contains
438 * a field named 'message' of type GST_TYPE_MESSAGE that contains the original
443 g_object_class_install_property (gobject_class, PROP_MESSAGE_FORWARD,
444 g_param_spec_boolean ("message-forward", "Message Forward",
445 "Forwards all children messages",
446 DEFAULT_MESSAGE_FORWARD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
448 gobject_class->dispose = gst_bin_dispose;
450 gst_element_class_set_metadata (gstelement_class, "Generic bin",
452 "Simple container object",
453 "Erik Walthinsen <omega@cse.ogi.edu>,"
454 "Wim Taymans <wim.taymans@gmail.com>");
456 gstelement_class->change_state =
457 GST_DEBUG_FUNCPTR (gst_bin_change_state_func);
458 gstelement_class->state_changed = GST_DEBUG_FUNCPTR (gst_bin_state_changed);
459 gstelement_class->get_state = GST_DEBUG_FUNCPTR (gst_bin_get_state_func);
461 gstelement_class->get_index = GST_DEBUG_FUNCPTR (gst_bin_get_index_func);
462 gstelement_class->set_index = GST_DEBUG_FUNCPTR (gst_bin_set_index_func);
464 gstelement_class->provide_clock =
465 GST_DEBUG_FUNCPTR (gst_bin_provide_clock_func);
466 gstelement_class->set_clock = GST_DEBUG_FUNCPTR (gst_bin_set_clock_func);
468 gstelement_class->send_event = GST_DEBUG_FUNCPTR (gst_bin_send_event);
469 gstelement_class->query = GST_DEBUG_FUNCPTR (gst_bin_query);
471 klass->add_element = GST_DEBUG_FUNCPTR (gst_bin_add_func);
472 klass->remove_element = GST_DEBUG_FUNCPTR (gst_bin_remove_func);
473 klass->handle_message = GST_DEBUG_FUNCPTR (gst_bin_handle_message_func);
475 klass->do_latency = GST_DEBUG_FUNCPTR (gst_bin_do_latency_func);
477 GST_DEBUG ("creating bin thread pool");
480 g_thread_pool_new ((GFunc) gst_bin_continue_func, NULL, -1, FALSE, &err);
482 g_critical ("could alloc threadpool %s", err->message);
487 gst_bin_init (GstBin * bin)
491 bin->numchildren = 0;
492 bin->children = NULL;
493 bin->children_cookie = 0;
494 bin->messages = NULL;
495 bin->provided_clock = NULL;
496 bin->clock_dirty = FALSE;
498 /* Set up a bus for listening to child elements */
499 bus = g_object_new (GST_TYPE_BUS, "enable-async", FALSE, NULL);
500 bin->child_bus = bus;
501 GST_DEBUG_OBJECT (bin, "using bus %" GST_PTR_FORMAT " to listen to children",
503 gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bin_bus_handler, bin,
506 bin->priv = GST_BIN_GET_PRIVATE (bin);
507 bin->priv->asynchandling = DEFAULT_ASYNC_HANDLING;
508 bin->priv->structure_cookie = 0;
509 bin->priv->message_forward = DEFAULT_MESSAGE_FORWARD;
513 gst_bin_dispose (GObject * object)
515 GstBin *bin = GST_BIN_CAST (object);
516 GstBus **child_bus_p = &bin->child_bus;
517 GstClock **provided_clock_p = &bin->provided_clock;
518 GstElement **clock_provider_p = &bin->clock_provider;
520 GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
522 GST_OBJECT_LOCK (object);
523 gst_object_replace ((GstObject **) child_bus_p, NULL);
524 gst_object_replace ((GstObject **) provided_clock_p, NULL);
525 gst_object_replace ((GstObject **) clock_provider_p, NULL);
526 bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
527 GST_OBJECT_UNLOCK (object);
529 while (bin->children) {
530 gst_bin_remove (bin, GST_ELEMENT_CAST (bin->children->data));
532 if (G_UNLIKELY (bin->children != NULL)) {
533 g_critical ("could not remove elements from bin '%s'",
534 GST_STR_NULL (GST_OBJECT_NAME (object)));
537 G_OBJECT_CLASS (parent_class)->dispose (object);
542 * @name: the name of the new bin
544 * Creates a new bin with the given name.
546 * Returns: (transfer floating): a new #GstBin
549 gst_bin_new (const gchar * name)
551 return gst_element_factory_make ("bin", name);
555 gst_bin_set_property (GObject * object, guint prop_id,
556 const GValue * value, GParamSpec * pspec)
560 gstbin = GST_BIN_CAST (object);
563 case PROP_ASYNC_HANDLING:
564 GST_OBJECT_LOCK (gstbin);
565 gstbin->priv->asynchandling = g_value_get_boolean (value);
566 GST_OBJECT_UNLOCK (gstbin);
568 case PROP_MESSAGE_FORWARD:
569 GST_OBJECT_LOCK (gstbin);
570 gstbin->priv->message_forward = g_value_get_boolean (value);
571 GST_OBJECT_UNLOCK (gstbin);
574 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
580 gst_bin_get_property (GObject * object, guint prop_id,
581 GValue * value, GParamSpec * pspec)
585 gstbin = GST_BIN_CAST (object);
588 case PROP_ASYNC_HANDLING:
589 GST_OBJECT_LOCK (gstbin);
590 g_value_set_boolean (value, gstbin->priv->asynchandling);
591 GST_OBJECT_UNLOCK (gstbin);
593 case PROP_MESSAGE_FORWARD:
594 GST_OBJECT_LOCK (gstbin);
595 g_value_set_boolean (value, gstbin->priv->message_forward);
596 GST_OBJECT_UNLOCK (gstbin);
599 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
605 /* return the cached index */
607 gst_bin_get_index_func (GstElement * element)
612 bin = GST_BIN_CAST (element);
614 GST_OBJECT_LOCK (bin);
615 if ((result = bin->priv->index))
616 gst_object_ref (result);
617 GST_OBJECT_UNLOCK (bin);
622 /* set the index on all elements in this bin
627 gst_bin_set_index_func (GstElement * element, GstIndex * index)
633 GValue data = { 0, };
635 bin = GST_BIN_CAST (element);
637 GST_OBJECT_LOCK (bin);
638 old = bin->priv->index;
639 if (G_UNLIKELY (old == index))
642 gst_object_ref (index);
643 bin->priv->index = index;
644 GST_OBJECT_UNLOCK (bin);
647 gst_object_unref (old);
649 it = gst_bin_iterate_elements (bin);
651 /* set the index on all elements in the bin */
654 switch (gst_iterator_next (it, &data)) {
655 case GST_ITERATOR_OK:
657 GstElement *child = g_value_get_object (&data);
659 GST_DEBUG_OBJECT (bin, "setting index on '%s'",
660 GST_ELEMENT_NAME (child));
661 gst_element_set_index (child, index);
663 g_value_reset (&data);
666 case GST_ITERATOR_RESYNC:
667 GST_DEBUG_OBJECT (bin, "iterator doing resync");
668 gst_iterator_resync (it);
671 case GST_ITERATOR_DONE:
672 GST_DEBUG_OBJECT (bin, "iterator done");
677 g_value_unset (&data);
678 gst_iterator_free (it);
683 GST_DEBUG_OBJECT (bin, "index was already set");
684 GST_OBJECT_UNLOCK (bin);
690 /* set the clock on all elements in this bin
695 gst_bin_set_clock_func (GstElement * element, GstClock * clock)
701 GValue data = { 0, };
703 bin = GST_BIN_CAST (element);
705 it = gst_bin_iterate_elements (bin);
709 switch (gst_iterator_next (it, &data)) {
710 case GST_ITERATOR_OK:
712 GstElement *child = g_value_get_object (&data);
714 res &= gst_element_set_clock (child, clock);
716 g_value_reset (&data);
719 case GST_ITERATOR_RESYNC:
720 GST_DEBUG_OBJECT (bin, "iterator doing resync");
721 gst_iterator_resync (it);
725 case GST_ITERATOR_DONE:
726 GST_DEBUG_OBJECT (bin, "iterator done");
731 g_value_unset (&data);
732 gst_iterator_free (it);
735 res = GST_ELEMENT_CLASS (parent_class)->set_clock (element, clock);
740 /* get the clock for this bin by asking all of the children in this bin
742 * The ref of the returned clock in increased so unref after usage.
744 * We loop the elements in state order and pick the last clock we can
745 * get. This makes sure we get a clock from the source.
750 gst_bin_provide_clock_func (GstElement * element)
752 GstClock *result = NULL;
753 GstElement *provider = NULL;
758 GstClock **provided_clock_p;
759 GstElement **clock_provider_p;
761 bin = GST_BIN_CAST (element);
763 GST_OBJECT_LOCK (bin);
764 if (!bin->clock_dirty)
767 GST_DEBUG_OBJECT (bin, "finding new clock");
769 it = gst_bin_sort_iterator_new (bin);
770 GST_OBJECT_UNLOCK (bin);
774 switch (gst_iterator_next (it, &val)) {
775 case GST_ITERATOR_OK:
777 GstElement *child = g_value_get_object (&val);
780 clock = gst_element_provide_clock (child);
782 GST_DEBUG_OBJECT (bin, "found candidate clock %p by element %s",
783 clock, GST_ELEMENT_NAME (child));
785 gst_object_unref (result);
786 gst_object_unref (provider);
789 provider = gst_object_ref (child);
792 g_value_reset (&val);
795 case GST_ITERATOR_RESYNC:
796 gst_iterator_resync (it);
799 case GST_ITERATOR_DONE:
804 g_value_unset (&val);
805 gst_iterator_free (it);
807 GST_OBJECT_LOCK (bin);
808 if (!bin->clock_dirty) {
810 gst_object_unref (provider);
812 gst_object_unref (result);
818 provided_clock_p = &bin->provided_clock;
819 clock_provider_p = &bin->clock_provider;
820 gst_object_replace ((GstObject **) provided_clock_p, (GstObject *) result);
821 gst_object_replace ((GstObject **) clock_provider_p, (GstObject *) provider);
822 bin->clock_dirty = FALSE;
823 GST_DEBUG_OBJECT (bin,
824 "provided new clock %" GST_PTR_FORMAT " by provider %" GST_PTR_FORMAT,
826 /* Provider is not being returned to caller, just the result */
828 gst_object_unref (provider);
829 GST_OBJECT_UNLOCK (bin);
835 if ((result = bin->provided_clock))
836 gst_object_ref (result);
837 GST_DEBUG_OBJECT (bin, "returning old clock %p", result);
838 GST_OBJECT_UNLOCK (bin);
845 * functions for manipulating cached messages
850 GstMessageType types;
853 /* check if a message is of given src and type */
855 message_check (GstMessage * message, MessageFind * target)
860 eq &= GST_MESSAGE_SRC (message) == target->src;
862 eq &= (GST_MESSAGE_TYPE (message) & target->types) != 0;
863 GST_LOG ("looking at message %p: %d", message, eq);
869 find_message (GstBin * bin, GstObject * src, GstMessageType types)
877 result = g_list_find_custom (bin->messages, &find,
878 (GCompareFunc) message_check);
881 GST_DEBUG_OBJECT (bin, "we found a message %p from %s matching types %08x",
882 result->data, GST_OBJECT_NAME (GST_MESSAGE_CAST (result->data)->src),
885 GST_DEBUG_OBJECT (bin, "no message found matching types %08x", types);
886 #ifndef GST_DISABLE_GST_DEBUG
890 for (i = 0; i < 32; i++)
891 if (types & (1 << i))
892 GST_DEBUG_OBJECT (bin, " %s", gst_message_type_get_name (1 << i));
900 /* with LOCK, returns TRUE if message had a valid SRC, takes ownership of
903 * A message that is cached and has the same SRC and type is replaced
904 * by the given message.
907 bin_replace_message (GstBin * bin, GstMessage * message, GstMessageType types)
913 if ((src = GST_MESSAGE_SRC (message))) {
914 /* first find the previous message posted by this element */
915 if ((previous = find_message (bin, src, types))) {
916 GstMessage *previous_msg;
918 /* if we found a previous message, replace it */
919 previous_msg = previous->data;
920 previous->data = message;
922 GST_DEBUG_OBJECT (bin, "replace old message %s from %s with %s message",
923 GST_MESSAGE_TYPE_NAME (previous_msg), GST_ELEMENT_NAME (src),
924 GST_MESSAGE_TYPE_NAME (message));
926 gst_message_unref (previous_msg);
928 /* keep new message */
929 bin->messages = g_list_prepend (bin->messages, message);
931 GST_DEBUG_OBJECT (bin, "got new message %p, %s from %s",
932 message, GST_MESSAGE_TYPE_NAME (message), GST_ELEMENT_NAME (src));
935 GST_DEBUG_OBJECT (bin, "got message %s from (NULL), not processing",
936 GST_MESSAGE_TYPE_NAME (message));
938 gst_message_unref (message);
943 /* with LOCK. Remove all messages of given types */
945 bin_remove_messages (GstBin * bin, GstObject * src, GstMessageType types)
953 for (walk = bin->messages; walk; walk = next) {
954 GstMessage *message = (GstMessage *) walk->data;
956 next = g_list_next (walk);
958 if (message_check (message, &find) == 0) {
959 GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
960 "deleting message %p of types 0x%08x", message, types);
961 bin->messages = g_list_delete_link (bin->messages, walk);
962 gst_message_unref (message);
964 GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
965 "not deleting message %p of type 0x%08x", message,
966 GST_MESSAGE_TYPE (message));
972 /* Check if the bin is EOS. We do this by scanning all sinks and
973 * checking if they posted an EOS message.
975 * call with bin LOCK */
977 is_eos (GstBin * bin, guint32 * seqnum)
984 for (walk = bin->children; walk; walk = g_list_next (walk)) {
987 element = GST_ELEMENT_CAST (walk->data);
988 if (bin_element_is_sink (element, bin) == 0) {
989 /* check if element posted EOS */
991 find_message (bin, GST_OBJECT_CAST (element), GST_MESSAGE_EOS))) {
992 GST_DEBUG ("sink '%s' posted EOS", GST_ELEMENT_NAME (element));
993 *seqnum = gst_message_get_seqnum (GST_MESSAGE_CAST (msgs->data));
996 GST_DEBUG ("sink '%s' did not post EOS yet",
997 GST_ELEMENT_NAME (element));
1003 /* FIXME: Some tests (e.g. elements/capsfilter) use
1004 * pipelines with a dangling sinkpad but no sink element.
1005 * These tests assume that no EOS message is ever
1006 * posted on the bus so let's keep that behaviour.
1007 * In valid pipelines this doesn't make a difference.
1009 return result && n_eos > 0;
1013 /* Check if the bin is STREAM_START. We do this by scanning all sinks and
1014 * checking if they posted an STREAM_START message.
1016 * call with bin LOCK */
1018 is_stream_start (GstBin * bin, guint32 * seqnum)
1021 gint n_stream_start = 0;
1025 for (walk = bin->children; walk; walk = g_list_next (walk)) {
1026 GstElement *element;
1028 element = GST_ELEMENT_CAST (walk->data);
1029 if (bin_element_is_sink (element, bin) == 0) {
1030 /* check if element posted STREAM_START */
1032 find_message (bin, GST_OBJECT_CAST (element),
1033 GST_MESSAGE_STREAM_START))) {
1034 GST_DEBUG ("sink '%s' posted STREAM_START", GST_ELEMENT_NAME (element));
1035 *seqnum = gst_message_get_seqnum (GST_MESSAGE_CAST (msgs->data));
1038 GST_DEBUG ("sink '%s' did not post STREAM_START yet",
1039 GST_ELEMENT_NAME (element));
1050 unlink_pads (const GValue * item, gpointer user_data)
1055 pad = g_value_get_object (item);
1057 if ((peer = gst_pad_get_peer (pad))) {
1058 if (gst_pad_get_direction (pad) == GST_PAD_SRC)
1059 gst_pad_unlink (pad, peer);
1061 gst_pad_unlink (peer, pad);
1062 gst_object_unref (peer);
1066 /* vmethod that adds an element to a bin
1071 gst_bin_add_func (GstBin * bin, GstElement * element)
1075 gboolean is_sink, is_source, provides_clock, requires_clock;
1076 GstMessage *clock_message = NULL, *async_message = NULL;
1077 GstStateChangeReturn ret;
1079 GST_DEBUG_OBJECT (bin, "element :%s", GST_ELEMENT_NAME (element));
1081 /* we obviously can't add ourself to ourself */
1082 if (G_UNLIKELY (GST_ELEMENT_CAST (element) == GST_ELEMENT_CAST (bin)))
1085 /* get the element name to make sure it is unique in this bin. */
1086 GST_OBJECT_LOCK (element);
1087 elem_name = g_strdup (GST_ELEMENT_NAME (element));
1088 is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SINK);
1089 is_source = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SOURCE);
1091 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1093 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1094 GST_OBJECT_UNLOCK (element);
1096 GST_OBJECT_LOCK (bin);
1098 /* then check to see if the element's name is already taken in the bin,
1099 * we can safely take the lock here. This check is probably bogus because
1100 * you can safely change the element name after this check and before setting
1101 * the object parent. The window is very small though... */
1102 if (G_UNLIKELY (!gst_object_check_uniqueness (bin->children, elem_name)))
1103 goto duplicate_name;
1105 /* set the element's parent and add the element to the bin's list of children */
1106 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (element),
1107 GST_OBJECT_CAST (bin))))
1110 /* if we add a sink we become a sink */
1112 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was sink",
1114 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_SINK);
1117 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was source",
1119 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_SOURCE);
1121 if (provides_clock) {
1122 GST_DEBUG_OBJECT (bin, "element \"%s\" can provide a clock", elem_name);
1124 gst_message_new_clock_provide (GST_OBJECT_CAST (element), NULL, TRUE);
1125 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1127 if (requires_clock) {
1128 GST_DEBUG_OBJECT (bin, "element \"%s\" requires a clock", elem_name);
1129 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1132 bin->children = g_list_prepend (bin->children, element);
1134 bin->children_cookie++;
1135 bin->priv->structure_cookie++;
1137 /* distribute the bus */
1138 gst_element_set_bus (element, bin->child_bus);
1140 /* propagate the current base_time, start_time and clock */
1141 gst_element_set_base_time (element, GST_ELEMENT_CAST (bin)->base_time);
1142 gst_element_set_start_time (element, GST_ELEMENT_START_TIME (bin));
1143 /* it's possible that the element did not accept the clock but
1144 * that is not important right now. When the pipeline goes to PLAYING,
1145 * a new clock will be selected */
1146 gst_element_set_clock (element, GST_ELEMENT_CLOCK (bin));
1149 /* set the cached index on the children */
1150 if (bin->priv->index)
1151 gst_element_set_index (element, bin->priv->index);
1154 ret = GST_STATE_RETURN (bin);
1155 /* no need to update the state if we are in error */
1156 if (ret == GST_STATE_CHANGE_FAILURE)
1157 goto no_state_recalc;
1159 /* update the bin state, the new element could have been an ASYNC or
1160 * NO_PREROLL element */
1161 ret = GST_STATE_RETURN (element);
1162 GST_DEBUG_OBJECT (bin, "added %s element",
1163 gst_element_state_change_return_get_name (ret));
1166 case GST_STATE_CHANGE_ASYNC:
1168 /* create message to track this aync element when it posts an async-done
1170 async_message = gst_message_new_async_start (GST_OBJECT_CAST (element));
1173 case GST_STATE_CHANGE_NO_PREROLL:
1174 /* ignore all async elements we might have and commit our state */
1175 bin_handle_async_done (bin, ret, FALSE, GST_CLOCK_TIME_NONE);
1177 case GST_STATE_CHANGE_FAILURE:
1184 GST_OBJECT_UNLOCK (bin);
1186 /* post the messages on the bus of the element so that the bin can handle
1189 gst_element_post_message (GST_ELEMENT_CAST (element), clock_message);
1192 gst_element_post_message (GST_ELEMENT_CAST (element), async_message);
1194 /* unlink all linked pads */
1195 it = gst_element_iterate_pads (element);
1196 gst_iterator_foreach (it, (GstIteratorForeachFunction) unlink_pads, NULL);
1197 gst_iterator_free (it);
1199 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "added element \"%s\"",
1202 g_signal_emit (bin, gst_bin_signals[ELEMENT_ADDED], 0, element);
1203 gst_child_proxy_child_added ((GstChildProxy *) bin, (GObject *) element,
1210 /* ERROR handling here */
1213 GST_OBJECT_LOCK (bin);
1214 g_warning ("Cannot add bin '%s' to itself", GST_ELEMENT_NAME (bin));
1215 GST_OBJECT_UNLOCK (bin);
1220 g_warning ("Name '%s' is not unique in bin '%s', not adding",
1221 elem_name, GST_ELEMENT_NAME (bin));
1222 GST_OBJECT_UNLOCK (bin);
1228 g_warning ("Element '%s' already has parent", elem_name);
1229 GST_OBJECT_UNLOCK (bin);
1238 * @element: (transfer full): the #GstElement to add
1240 * Adds the given element to the bin. Sets the element's parent, and thus
1241 * takes ownership of the element. An element can only be added to one bin.
1243 * If the element's pads are linked to other pads, the pads will be unlinked
1244 * before the element is added to the bin.
1247 * When you add an element to an already-running pipeline, you will have to
1248 * take care to set the state of the newly-added element to the desired
1249 * state (usually PLAYING or PAUSED, same you set the pipeline to originally)
1250 * with gst_element_set_state(), or use gst_element_sync_state_with_parent().
1251 * The bin or pipeline will not take care of this for you.
1256 * Returns: TRUE if the element could be added, FALSE if
1257 * the bin does not want to accept the element.
1260 gst_bin_add (GstBin * bin, GstElement * element)
1262 GstBinClass *bclass;
1265 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
1266 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1268 bclass = GST_BIN_GET_CLASS (bin);
1270 if (G_UNLIKELY (bclass->add_element == NULL))
1273 GST_CAT_DEBUG (GST_CAT_PARENTAGE, "adding element %s to bin %s",
1274 GST_STR_NULL (GST_ELEMENT_NAME (element)),
1275 GST_STR_NULL (GST_ELEMENT_NAME (bin)));
1277 result = bclass->add_element (bin, element);
1281 /* ERROR handling */
1284 g_warning ("adding elements to bin '%s' is not supported",
1285 GST_ELEMENT_NAME (bin));
1290 /* remove an element from the bin
1295 gst_bin_remove_func (GstBin * bin, GstElement * element)
1299 gboolean is_sink, is_source, provides_clock, requires_clock;
1300 gboolean othersink, othersource, otherprovider, otherrequirer, found;
1301 GstMessage *clock_message = NULL;
1302 GstClock **provided_clock_p;
1303 GstElement **clock_provider_p;
1305 gboolean other_async, this_async, have_no_preroll;
1306 GstStateChangeReturn ret;
1308 GST_DEBUG_OBJECT (bin, "element :%s", GST_ELEMENT_NAME (element));
1310 GST_OBJECT_LOCK (bin);
1312 GST_OBJECT_LOCK (element);
1313 elem_name = g_strdup (GST_ELEMENT_NAME (element));
1315 if (GST_OBJECT_PARENT (element) != GST_OBJECT_CAST (bin))
1318 /* remove the parent ref */
1319 GST_OBJECT_PARENT (element) = NULL;
1321 /* grab element name so we can print it */
1322 is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SINK);
1323 is_source = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SOURCE);
1325 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1327 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1328 GST_OBJECT_UNLOCK (element);
1332 othersource = FALSE;
1333 otherprovider = FALSE;
1334 otherrequirer = FALSE;
1335 have_no_preroll = FALSE;
1336 /* iterate the elements, we collect which ones are async and no_preroll. We
1337 * also remove the element when we find it. */
1338 for (walk = bin->children; walk; walk = next) {
1339 GstElement *child = GST_ELEMENT_CAST (walk->data);
1341 next = g_list_next (walk);
1343 if (child == element) {
1345 /* remove the element */
1346 bin->children = g_list_delete_link (bin->children, walk);
1348 gboolean child_sink, child_source, child_provider, child_requirer;
1350 GST_OBJECT_LOCK (child);
1351 child_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SINK);
1352 child_source = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SOURCE);
1354 GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1356 GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1357 /* when we remove a sink, check if there are other sinks. */
1358 if (is_sink && !othersink && child_sink)
1360 if (is_source && !othersource && child_source)
1362 if (provides_clock && !otherprovider && child_provider)
1363 otherprovider = TRUE;
1364 if (requires_clock && !otherrequirer && child_requirer)
1365 otherrequirer = TRUE;
1366 /* check if we have NO_PREROLL children */
1367 if (GST_STATE_RETURN (child) == GST_STATE_CHANGE_NO_PREROLL)
1368 have_no_preroll = TRUE;
1369 GST_OBJECT_UNLOCK (child);
1373 /* the element must have been in the bin's list of children */
1374 if (G_UNLIKELY (!found))
1377 /* we now removed the element from the list of elements, increment the cookie
1378 * so that others can detect a change in the children list. */
1380 bin->children_cookie++;
1381 bin->priv->structure_cookie++;
1383 if (is_sink && !othersink) {
1384 /* we're not a sink anymore */
1385 GST_DEBUG_OBJECT (bin, "we removed the last sink");
1386 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_SINK);
1388 if (is_source && !othersource) {
1389 /* we're not a source anymore */
1390 GST_DEBUG_OBJECT (bin, "we removed the last source");
1391 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_SOURCE);
1393 if (provides_clock && !otherprovider) {
1394 /* we're not a clock provider anymore */
1395 GST_DEBUG_OBJECT (bin, "we removed the last clock provider");
1396 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1398 if (requires_clock && !otherrequirer) {
1399 /* we're not a clock requirer anymore */
1400 GST_DEBUG_OBJECT (bin, "we removed the last clock requirer");
1401 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1404 /* if the clock provider for this element is removed, we lost
1405 * the clock as well, we need to inform the parent of this
1406 * so that it can select a new clock */
1407 if (bin->clock_provider == element) {
1408 GST_DEBUG_OBJECT (bin, "element \"%s\" provided the clock", elem_name);
1409 bin->clock_dirty = TRUE;
1411 gst_message_new_clock_lost (GST_OBJECT_CAST (bin), bin->provided_clock);
1412 provided_clock_p = &bin->provided_clock;
1413 clock_provider_p = &bin->clock_provider;
1414 gst_object_replace ((GstObject **) provided_clock_p, NULL);
1415 gst_object_replace ((GstObject **) clock_provider_p, NULL);
1418 /* remove messages for the element, if there was a pending ASYNC_START
1419 * message we must see if removing the element caused the bin to lose its
1422 other_async = FALSE;
1423 for (walk = bin->messages; walk; walk = next) {
1424 GstMessage *message = (GstMessage *) walk->data;
1425 GstElement *src = GST_ELEMENT_CAST (GST_MESSAGE_SRC (message));
1428 next = g_list_next (walk);
1431 switch (GST_MESSAGE_TYPE (message)) {
1432 case GST_MESSAGE_ASYNC_START:
1438 GST_DEBUG_OBJECT (src, "looking at message %p", message);
1440 case GST_MESSAGE_STRUCTURE_CHANGE:
1444 GST_DEBUG_OBJECT (src, "looking at structure change message %p",
1446 /* it's unlikely that this message is still in the list of messages
1447 * because this would mean that a link/unlink is busy in another thread
1448 * while we remove the element. We still have to remove the message
1449 * because we might not receive the done message anymore when the element
1450 * is removed from the bin. */
1451 gst_message_parse_structure_change (message, NULL, &owner, NULL);
1452 if (owner == element)
1463 /* delete all message types */
1464 GST_DEBUG_OBJECT (src, "deleting message %p of element \"%s\"",
1465 message, elem_name);
1466 bin->messages = g_list_delete_link (bin->messages, walk);
1467 gst_message_unref (message);
1471 /* get last return */
1472 ret = GST_STATE_RETURN (bin);
1474 /* no need to update the state if we are in error */
1475 if (ret == GST_STATE_CHANGE_FAILURE)
1476 goto no_state_recalc;
1478 if (!other_async && this_async) {
1479 /* all other elements were not async and we removed the async one,
1480 * handle the async-done case because we are not async anymore now. */
1481 GST_DEBUG_OBJECT (bin,
1482 "we removed the last async element, have no_preroll %d",
1485 /* the current state return of the bin depends on if there are no_preroll
1486 * elements in the pipeline or not */
1487 if (have_no_preroll)
1488 ret = GST_STATE_CHANGE_NO_PREROLL;
1490 ret = GST_STATE_CHANGE_SUCCESS;
1492 bin_handle_async_done (bin, ret, FALSE, GST_CLOCK_TIME_NONE);
1494 GST_DEBUG_OBJECT (bin,
1495 "recalc state preroll: %d, other async: %d, this async %d",
1496 have_no_preroll, other_async, this_async);
1498 if (have_no_preroll) {
1499 ret = GST_STATE_CHANGE_NO_PREROLL;
1500 } else if (other_async) {
1501 /* there are other async elements and we were not doing an async state
1502 * change, change our pending state and go async */
1503 if (GST_STATE_PENDING (bin) == GST_STATE_VOID_PENDING) {
1504 GST_STATE_NEXT (bin) = GST_STATE (bin);
1505 GST_STATE_PENDING (bin) = GST_STATE (bin);
1507 ret = GST_STATE_CHANGE_ASYNC;
1509 GST_STATE_RETURN (bin) = ret;
1513 gst_element_set_bus (element, NULL);
1514 /* Clear the clock we provided to the element */
1515 gst_element_set_clock (element, NULL);
1516 GST_OBJECT_UNLOCK (bin);
1519 gst_element_post_message (GST_ELEMENT_CAST (bin), clock_message);
1521 /* unlink all linked pads */
1522 it = gst_element_iterate_pads (element);
1523 gst_iterator_foreach (it, (GstIteratorForeachFunction) unlink_pads, NULL);
1524 gst_iterator_free (it);
1526 GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
1529 g_signal_emit (bin, gst_bin_signals[ELEMENT_REMOVED], 0, element);
1530 gst_child_proxy_child_removed ((GstChildProxy *) bin, (GObject *) element,
1534 /* element is really out of our control now */
1535 gst_object_unref (element);
1539 /* ERROR handling */
1542 g_warning ("Element '%s' is not in bin '%s'", elem_name,
1543 GST_ELEMENT_NAME (bin));
1544 GST_OBJECT_UNLOCK (element);
1545 GST_OBJECT_UNLOCK (bin);
1554 * @element: (transfer none): the #GstElement to remove
1556 * Removes the element from the bin, unparenting it as well.
1557 * Unparenting the element means that the element will be dereferenced,
1558 * so if the bin holds the only reference to the element, the element
1559 * will be freed in the process of removing it from the bin. If you
1560 * want the element to still exist after removing, you need to call
1561 * gst_object_ref() before removing it from the bin.
1563 * If the element's pads are linked to other pads, the pads will be unlinked
1564 * before the element is removed from the bin.
1568 * Returns: TRUE if the element could be removed, FALSE if
1569 * the bin does not want to remove the element.
1572 gst_bin_remove (GstBin * bin, GstElement * element)
1574 GstBinClass *bclass;
1577 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
1578 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1580 bclass = GST_BIN_GET_CLASS (bin);
1582 if (G_UNLIKELY (bclass->remove_element == NULL))
1585 GST_CAT_DEBUG (GST_CAT_PARENTAGE, "removing element %s from bin %s",
1586 GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
1588 result = bclass->remove_element (bin, element);
1592 /* ERROR handling */
1595 g_warning ("removing elements from bin '%s' is not supported",
1596 GST_ELEMENT_NAME (bin));
1602 * gst_bin_iterate_elements:
1605 * Gets an iterator for the elements in this bin.
1607 * Each element yielded by the iterator will have its refcount increased, so
1610 * MT safe. Caller owns returned value.
1612 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1615 gst_bin_iterate_elements (GstBin * bin)
1617 GstIterator *result;
1619 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1621 GST_OBJECT_LOCK (bin);
1622 result = gst_iterator_new_list (GST_TYPE_ELEMENT,
1623 GST_OBJECT_GET_LOCK (bin),
1624 &bin->children_cookie, &bin->children, (GObject *) bin, NULL);
1625 GST_OBJECT_UNLOCK (bin);
1630 static GstIteratorItem
1631 iterate_child_recurse (GstIterator * it, const GValue * item)
1633 GstElement *child = g_value_get_object (item);
1635 if (GST_IS_BIN (child)) {
1636 GstIterator *other = gst_bin_iterate_recurse (GST_BIN_CAST (child));
1638 gst_iterator_push (it, other);
1640 return GST_ITERATOR_ITEM_PASS;
1644 * gst_bin_iterate_recurse:
1647 * Gets an iterator for the elements in this bin.
1648 * This iterator recurses into GstBin children.
1650 * Each element yielded by the iterator will have its refcount increased, so
1653 * MT safe. Caller owns returned value.
1655 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1658 gst_bin_iterate_recurse (GstBin * bin)
1660 GstIterator *result;
1662 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1664 GST_OBJECT_LOCK (bin);
1665 result = gst_iterator_new_list (GST_TYPE_ELEMENT,
1666 GST_OBJECT_GET_LOCK (bin),
1667 &bin->children_cookie,
1669 (GObject *) bin, (GstIteratorItemFunction) iterate_child_recurse);
1670 GST_OBJECT_UNLOCK (bin);
1675 /* returns 0 when TRUE because this is a GCompareFunc */
1678 bin_element_is_sink (GstElement * child, GstBin * bin)
1682 /* we lock the child here for the remainder of the function to
1683 * get its name and flag safely. */
1684 GST_OBJECT_LOCK (child);
1685 is_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SINK);
1687 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
1688 "child %s %s sink", GST_OBJECT_NAME (child), is_sink ? "is" : "is not");
1690 GST_OBJECT_UNLOCK (child);
1691 return is_sink ? 0 : 1;
1695 sink_iterator_filter (const GValue * vchild, GValue * vbin)
1697 GstBin *bin = g_value_get_object (vbin);
1698 GstElement *child = g_value_get_object (vchild);
1700 return (bin_element_is_sink (child, bin));
1704 * gst_bin_iterate_sinks:
1707 * Gets an iterator for all elements in the bin that have the
1708 * #GST_ELEMENT_FLAG_SINK flag set.
1710 * Each element yielded by the iterator will have its refcount increased, so
1713 * MT safe. Caller owns returned value.
1715 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1718 gst_bin_iterate_sinks (GstBin * bin)
1720 GstIterator *children;
1721 GstIterator *result;
1722 GValue vbin = { 0, };
1724 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1726 g_value_init (&vbin, GST_TYPE_BIN);
1727 g_value_set_object (&vbin, bin);
1729 children = gst_bin_iterate_elements (bin);
1730 result = gst_iterator_filter (children,
1731 (GCompareFunc) sink_iterator_filter, &vbin);
1733 g_value_unset (&vbin);
1738 /* returns 0 when TRUE because this is a GCompareFunc */
1741 bin_element_is_src (GstElement * child, GstBin * bin)
1745 /* we lock the child here for the remainder of the function to
1746 * get its name and other info safely. */
1747 GST_OBJECT_LOCK (child);
1748 is_src = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SOURCE);
1750 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
1751 "child %s %s src", GST_OBJECT_NAME (child), is_src ? "is" : "is not");
1753 GST_OBJECT_UNLOCK (child);
1754 return is_src ? 0 : 1;
1758 src_iterator_filter (const GValue * vchild, GValue * vbin)
1760 GstBin *bin = g_value_get_object (vbin);
1761 GstElement *child = g_value_get_object (vchild);
1763 return (bin_element_is_src (child, bin));
1767 * gst_bin_iterate_sources:
1770 * Gets an iterator for all elements in the bin that have the
1771 * #GST_ELEMENT_FLAG_SOURCE flag set.
1773 * Each element yielded by the iterator will have its refcount increased, so
1776 * MT safe. Caller owns returned value.
1778 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1781 gst_bin_iterate_sources (GstBin * bin)
1783 GstIterator *children;
1784 GstIterator *result;
1785 GValue vbin = { 0, };
1787 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1789 g_value_init (&vbin, GST_TYPE_BIN);
1790 g_value_set_object (&vbin, bin);
1792 children = gst_bin_iterate_elements (bin);
1793 result = gst_iterator_filter (children,
1794 (GCompareFunc) src_iterator_filter, &vbin);
1796 g_value_unset (&vbin);
1804 static GstStateChangeReturn
1805 gst_bin_get_state_func (GstElement * element, GstState * state,
1806 GstState * pending, GstClockTime timeout)
1808 GstStateChangeReturn ret;
1810 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "getting state");
1813 GST_ELEMENT_CLASS (parent_class)->get_state (element, state, pending,
1819 /***********************************************
1820 * Topologically sorted iterator
1821 * see http://en.wikipedia.org/wiki/Topological_sorting
1823 * For each element in the graph, an entry is kept in a HashTable
1824 * with its number of srcpad connections (degree).
1825 * We then change state of all elements without dependencies
1826 * (degree 0) and decrement the degree of all elements connected
1827 * on the sinkpads. When an element reaches degree 0, its state is
1829 * When all elements are handled the algorithm stops.
1831 typedef struct _GstBinSortIterator
1834 GQueue queue; /* elements queued for state change */
1835 GstBin *bin; /* bin we iterate */
1836 gint mode; /* adding or removing dependency */
1837 GstElement *best; /* next element with least dependencies */
1838 gint best_deg; /* best degree */
1839 GHashTable *hash; /* hashtable with element dependencies */
1840 gboolean dirty; /* we detected structure change */
1841 } GstBinSortIterator;
1844 gst_bin_sort_iterator_copy (const GstBinSortIterator * it,
1845 GstBinSortIterator * copy)
1847 GHashTableIter iter;
1848 gpointer key, value;
1850 copy->queue = it->queue;
1851 g_queue_foreach (©->queue, (GFunc) gst_object_ref, NULL);
1853 copy->bin = gst_object_ref (it->bin);
1855 copy->best = gst_object_ref (it->best);
1857 copy->hash = g_hash_table_new (NULL, NULL);
1858 g_hash_table_iter_init (&iter, it->hash);
1859 while (g_hash_table_iter_next (&iter, &key, &value))
1860 g_hash_table_insert (copy->hash, key, value);
1863 /* we add and subtract 1 to make sure we don't confuse NULL and 0 */
1864 #define HASH_SET_DEGREE(bit, elem, deg) \
1865 g_hash_table_replace (bit->hash, elem, GINT_TO_POINTER(deg+1))
1866 #define HASH_GET_DEGREE(bit, elem) \
1867 (GPOINTER_TO_INT(g_hash_table_lookup (bit->hash, elem))-1)
1869 /* add element to queue of next elements in the iterator.
1870 * We push at the tail to give higher priority elements a
1873 add_to_queue (GstBinSortIterator * bit, GstElement * element)
1875 GST_DEBUG_OBJECT (bit->bin, "adding '%s' to queue",
1876 GST_ELEMENT_NAME (element));
1877 gst_object_ref (element);
1878 g_queue_push_tail (&bit->queue, element);
1879 HASH_SET_DEGREE (bit, element, -1);
1883 remove_from_queue (GstBinSortIterator * bit, GstElement * element)
1887 if ((find = g_queue_find (&bit->queue, element))) {
1888 GST_DEBUG_OBJECT (bit->bin, "removing '%s' from queue",
1889 GST_ELEMENT_NAME (element));
1891 g_queue_delete_link (&bit->queue, find);
1892 gst_object_unref (element);
1894 GST_DEBUG_OBJECT (bit->bin, "unable to remove '%s' from queue",
1895 GST_ELEMENT_NAME (element));
1899 /* clear the queue, unref all objects as we took a ref when
1900 * we added them to the queue */
1902 clear_queue (GQueue * queue)
1906 while ((p = g_queue_pop_head (queue)))
1907 gst_object_unref (p);
1910 /* set all degrees to 0. Elements marked as a sink are
1911 * added to the queue immediately. Since we only look at the SINK flag of the
1912 * element, it is possible that we add non-sinks to the queue. These will be
1913 * removed from the queue again when we can prove that it provides data for some
1916 reset_degree (GstElement * element, GstBinSortIterator * bit)
1920 /* sinks are added right away */
1921 GST_OBJECT_LOCK (element);
1922 is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SINK);
1923 GST_OBJECT_UNLOCK (element);
1926 add_to_queue (bit, element);
1928 /* others are marked with 0 and handled when sinks are done */
1929 HASH_SET_DEGREE (bit, element, 0);
1933 /* adjust the degree of all elements connected to the given
1934 * element. If a degree of an element drops to 0, it is
1935 * added to the queue of elements to schedule next.
1937 * We have to make sure not to cross the bin boundary this element
1941 update_degree (GstElement * element, GstBinSortIterator * bit)
1943 gboolean linked = FALSE;
1945 GST_OBJECT_LOCK (element);
1946 /* don't touch degree if element has no sinkpads */
1947 if (element->numsinkpads != 0) {
1948 /* loop over all sinkpads, decrement degree for all connected
1949 * elements in this bin */
1952 for (pads = element->sinkpads; pads; pads = g_list_next (pads)) {
1955 pad = GST_PAD_CAST (pads->data);
1957 /* we're iterating over the sinkpads, check if it's busy in a link/unlink */
1958 if (G_UNLIKELY (find_message (bit->bin, GST_OBJECT_CAST (pad),
1959 GST_MESSAGE_STRUCTURE_CHANGE))) {
1960 /* mark the iterator as dirty because we won't be updating the degree
1961 * of the peer parent now. This would result in the 'loop detected'
1962 * later on because the peer parent element could become the best next
1963 * element with a degree > 0. We will simply continue our state
1964 * changes and we'll eventually resync when the unlink completed and
1965 * the iterator cookie is updated. */
1970 if ((peer = gst_pad_get_peer (pad))) {
1971 GstElement *peer_element;
1973 if ((peer_element = gst_pad_get_parent_element (peer))) {
1974 GST_OBJECT_LOCK (peer_element);
1975 /* check that we don't go outside of this bin */
1976 if (GST_OBJECT_CAST (peer_element)->parent ==
1977 GST_OBJECT_CAST (bit->bin)) {
1978 gint old_deg, new_deg;
1980 old_deg = HASH_GET_DEGREE (bit, peer_element);
1982 /* check to see if we added an element as sink that was not really a
1983 * sink because it was connected to some other element. */
1984 if (old_deg == -1) {
1985 remove_from_queue (bit, peer_element);
1988 new_deg = old_deg + bit->mode;
1990 GST_DEBUG_OBJECT (bit->bin,
1991 "change element %s, degree %d->%d, linked to %s",
1992 GST_ELEMENT_NAME (peer_element), old_deg, new_deg,
1993 GST_ELEMENT_NAME (element));
1995 /* update degree, it is possible that an element was in 0 and
1996 * reaches -1 here. This would mean that the element had no sinkpads
1997 * but became linked while the state change was happening. We will
1998 * resync on this with the structure change message. */
2000 /* degree hit 0, add to queue */
2001 add_to_queue (bit, peer_element);
2003 HASH_SET_DEGREE (bit, peer_element, new_deg);
2007 GST_OBJECT_UNLOCK (peer_element);
2008 gst_object_unref (peer_element);
2010 gst_object_unref (peer);
2015 GST_DEBUG_OBJECT (bit->bin, "element %s not linked on any sinkpads",
2016 GST_ELEMENT_NAME (element));
2018 GST_OBJECT_UNLOCK (element);
2021 /* find the next best element not handled yet. This is the one
2022 * with the lowest non-negative degree */
2024 find_element (GstElement * element, GstBinSortIterator * bit)
2028 /* element is already handled */
2029 if ((degree = HASH_GET_DEGREE (bit, element)) < 0)
2032 /* first element or element with smaller degree */
2033 if (bit->best == NULL || bit->best_deg > degree) {
2034 bit->best = element;
2035 bit->best_deg = degree;
2039 /* get next element in iterator. the returned element has the
2040 * refcount increased */
2041 static GstIteratorResult
2042 gst_bin_sort_iterator_next (GstBinSortIterator * bit, GValue * result)
2045 GstBin *bin = bit->bin;
2047 /* empty queue, we have to find a next best element */
2048 if (g_queue_is_empty (&bit->queue)) {
2050 bit->best_deg = G_MAXINT;
2051 g_list_foreach (bin->children, (GFunc) find_element, bit);
2052 if ((best = bit->best)) {
2053 /* when we detected an unlink, don't warn because our degrees might be
2054 * screwed up. We will resync later */
2055 if (bit->best_deg != 0 && !bit->dirty) {
2056 /* we don't fail on this one yet */
2057 GST_WARNING_OBJECT (bin, "loop dected in graph");
2058 g_warning ("loop detected in the graph of bin '%s'!!",
2059 GST_ELEMENT_NAME (bin));
2061 /* best unhandled element, schedule as next element */
2062 GST_DEBUG_OBJECT (bin, "queue empty, next best: %s",
2063 GST_ELEMENT_NAME (best));
2064 HASH_SET_DEGREE (bit, best, -1);
2065 g_value_set_object (result, best);
2067 GST_DEBUG_OBJECT (bin, "queue empty, elements exhausted");
2068 /* no more unhandled elements, we are done */
2069 return GST_ITERATOR_DONE;
2072 /* everything added to the queue got reffed */
2073 best = g_queue_pop_head (&bit->queue);
2074 g_value_set_object (result, best);
2075 gst_object_unref (best);
2078 GST_DEBUG_OBJECT (bin, "queue head gives %s", GST_ELEMENT_NAME (best));
2079 /* update degrees of linked elements */
2080 update_degree (best, bit);
2082 return GST_ITERATOR_OK;
2085 /* clear queues, recalculate the degrees and restart. */
2087 gst_bin_sort_iterator_resync (GstBinSortIterator * bit)
2089 GstBin *bin = bit->bin;
2091 GST_DEBUG_OBJECT (bin, "resync");
2093 clear_queue (&bit->queue);
2095 g_list_foreach (bin->children, (GFunc) reset_degree, bit);
2096 /* calc degrees, incrementing */
2098 g_list_foreach (bin->children, (GFunc) update_degree, bit);
2099 /* for the rest of the function we decrement the degrees */
2103 /* clear queues, unref bin and free iterator. */
2105 gst_bin_sort_iterator_free (GstBinSortIterator * bit)
2107 GstBin *bin = bit->bin;
2109 GST_DEBUG_OBJECT (bin, "free");
2110 clear_queue (&bit->queue);
2111 g_hash_table_destroy (bit->hash);
2112 gst_object_unref (bin);
2115 /* should be called with the bin LOCK held */
2116 static GstIterator *
2117 gst_bin_sort_iterator_new (GstBin * bin)
2119 GstBinSortIterator *result;
2121 /* we don't need an ItemFunction because we ref the items in the _next
2123 result = (GstBinSortIterator *)
2124 gst_iterator_new (sizeof (GstBinSortIterator),
2126 GST_OBJECT_GET_LOCK (bin),
2127 &bin->priv->structure_cookie,
2128 (GstIteratorCopyFunction) gst_bin_sort_iterator_copy,
2129 (GstIteratorNextFunction) gst_bin_sort_iterator_next,
2130 (GstIteratorItemFunction) NULL,
2131 (GstIteratorResyncFunction) gst_bin_sort_iterator_resync,
2132 (GstIteratorFreeFunction) gst_bin_sort_iterator_free);
2133 g_queue_init (&result->queue);
2134 result->hash = g_hash_table_new (NULL, NULL);
2135 gst_object_ref (bin);
2137 gst_bin_sort_iterator_resync (result);
2139 return (GstIterator *) result;
2143 * gst_bin_iterate_sorted:
2146 * Gets an iterator for the elements in this bin in topologically
2147 * sorted order. This means that the elements are returned from
2148 * the most downstream elements (sinks) to the sources.
2150 * This function is used internally to perform the state changes
2151 * of the bin elements and for clock selection.
2153 * Each element yielded by the iterator will have its refcount increased, so
2156 * MT safe. Caller owns returned value.
2158 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
2161 gst_bin_iterate_sorted (GstBin * bin)
2163 GstIterator *result;
2165 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
2167 GST_OBJECT_LOCK (bin);
2168 result = gst_bin_sort_iterator_new (bin);
2169 GST_OBJECT_UNLOCK (bin);
2174 static GstStateChangeReturn
2175 gst_bin_element_set_state (GstBin * bin, GstElement * element,
2176 GstClockTime base_time, GstClockTime start_time, GstState current,
2179 GstStateChangeReturn ret;
2180 GstState child_current, child_pending;
2184 GST_STATE_LOCK (element);
2186 GST_OBJECT_LOCK (element);
2187 /* set base_time and start time on child */
2188 GST_ELEMENT_START_TIME (element) = start_time;
2189 element->base_time = base_time;
2190 /* peel off the locked flag */
2191 locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2192 /* Get the previous set_state result to preserve NO_PREROLL and ASYNC */
2193 ret = GST_STATE_RETURN (element);
2194 child_current = GST_STATE (element);
2195 child_pending = GST_STATE_PENDING (element);
2196 GST_OBJECT_UNLOCK (element);
2198 /* skip locked elements */
2199 if (G_UNLIKELY (locked))
2202 /* if the element was no preroll, just start changing the state regardless
2203 * if it had async elements (in the case of a bin) because they won't preroll
2205 if (G_UNLIKELY (ret == GST_STATE_CHANGE_NO_PREROLL)) {
2206 GST_DEBUG_OBJECT (element, "element is NO_PREROLL, ignore async elements");
2210 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2211 "current %s pending %s, desired next %s",
2212 gst_element_state_get_name (child_current),
2213 gst_element_state_get_name (child_pending),
2214 gst_element_state_get_name (next));
2216 /* always recurse into bins so that we can set the base time */
2217 if (GST_IS_BIN (element))
2220 /* Try not to change the state of elements that are already in the state we're
2222 if (child_current == next && child_pending == GST_STATE_VOID_PENDING) {
2223 /* child is already at the requested state, return previous return. Note that
2224 * if the child has a pending state to next, we will still call the
2225 * set_state function */
2227 } else if (next > current) {
2228 /* upward state change */
2229 if (child_pending == GST_STATE_VOID_PENDING) {
2230 /* .. and the child is not busy doing anything */
2231 if (child_current > next) {
2232 /* .. and is already past the requested state, assume it got there
2234 ret = GST_STATE_CHANGE_SUCCESS;
2237 } else if (child_pending > child_current) {
2238 /* .. and the child is busy going upwards */
2239 if (child_current >= next) {
2240 /* .. and is already past the requested state, assume it got there
2242 ret = GST_STATE_CHANGE_SUCCESS;
2246 /* .. and the child is busy going downwards */
2247 if (child_current > next) {
2248 /* .. and is already past the requested state, assume it got there
2250 ret = GST_STATE_CHANGE_SUCCESS;
2254 } else if (next < current) {
2255 /* downward state change */
2256 if (child_pending == GST_STATE_VOID_PENDING) {
2257 /* .. and the child is not busy doing anything */
2258 if (child_current < next) {
2259 /* .. and is already past the requested state, assume it got there
2261 ret = GST_STATE_CHANGE_SUCCESS;
2264 } else if (child_pending < child_current) {
2265 /* .. and the child is busy going downwards */
2266 if (child_current <= next) {
2267 /* .. and is already past the requested state, assume it got there
2269 ret = GST_STATE_CHANGE_SUCCESS;
2273 /* .. and the child is busy going upwards */
2274 if (child_current < next) {
2275 /* .. and is already past the requested state, assume it got there
2277 ret = GST_STATE_CHANGE_SUCCESS;
2284 GST_OBJECT_LOCK (bin);
2285 /* the element was busy with an upwards async state change, we must wait for
2286 * an ASYNC_DONE message before we attemp to change the state. */
2288 find_message (bin, GST_OBJECT_CAST (element),
2289 GST_MESSAGE_ASYNC_START))) {
2290 #ifndef GST_DISABLE_GST_DEBUG
2291 GstMessage *message = GST_MESSAGE_CAST (found->data);
2293 GST_DEBUG_OBJECT (element, "element message %p, %s async busy",
2294 message, GST_ELEMENT_NAME (GST_MESSAGE_SRC (message)));
2296 /* only wait for upward state changes */
2297 if (next > current) {
2298 /* We found an async element check if we can force its state to change or
2299 * if we have to wait for it to preroll. */
2303 GST_OBJECT_UNLOCK (bin);
2306 GST_DEBUG_OBJECT (bin,
2307 "setting element %s to %s, base_time %" GST_TIME_FORMAT,
2308 GST_ELEMENT_NAME (element), gst_element_state_get_name (next),
2309 GST_TIME_ARGS (base_time));
2312 ret = gst_element_set_state (element, next);
2314 GST_STATE_UNLOCK (element);
2320 GST_DEBUG_OBJECT (element,
2321 "element is locked, return previous return %s",
2322 gst_element_state_change_return_get_name (ret));
2323 GST_STATE_UNLOCK (element);
2328 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2329 "skipping transition from %s to %s",
2330 gst_element_state_get_name (child_current),
2331 gst_element_state_get_name (next));
2332 GST_STATE_UNLOCK (element);
2337 GST_DEBUG_OBJECT (element, "element was busy, delaying state change");
2338 GST_OBJECT_UNLOCK (bin);
2339 GST_STATE_UNLOCK (element);
2340 return GST_STATE_CHANGE_ASYNC;
2344 /* gst_iterator_fold functions for pads_activate
2345 * Stop the iterator if activating one pad failed. */
2347 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2349 GstPad *pad = g_value_get_object (vpad);
2350 gboolean cont = TRUE;
2352 if (!(cont = gst_pad_set_active (pad, *active)))
2353 g_value_set_boolean (ret, FALSE);
2358 /* returns false on error or early cutout of the fold, true if all
2359 * pads in @iter were (de)activated successfully. */
2361 iterator_activate_fold_with_resync (GstIterator * iter, gpointer user_data)
2363 GstIteratorResult ires;
2366 /* no need to unset this later, it's just a boolean */
2367 g_value_init (&ret, G_TYPE_BOOLEAN);
2368 g_value_set_boolean (&ret, TRUE);
2371 ires = gst_iterator_fold (iter, (GstIteratorFoldFunction) activate_pads,
2374 case GST_ITERATOR_RESYNC:
2375 /* need to reset the result again */
2376 g_value_set_boolean (&ret, TRUE);
2377 gst_iterator_resync (iter);
2379 case GST_ITERATOR_DONE:
2380 /* all pads iterated, return collected value */
2383 /* iterator returned _ERROR or premature end with _OK,
2384 * mark an error and exit */
2385 g_value_set_boolean (&ret, FALSE);
2390 /* return collected value */
2391 return g_value_get_boolean (&ret);
2394 /* is called with STATE_LOCK
2397 gst_bin_src_pads_activate (GstBin * bin, gboolean active)
2402 GST_DEBUG_OBJECT (bin, "%s pads", active ? "activate" : "deactivate");
2404 iter = gst_element_iterate_src_pads ((GstElement *) bin);
2405 fold_ok = iterator_activate_fold_with_resync (iter, &active);
2406 gst_iterator_free (iter);
2407 if (G_UNLIKELY (!fold_ok))
2410 GST_DEBUG_OBJECT (bin, "pad %sactivation successful", active ? "" : "de");
2417 GST_DEBUG_OBJECT (bin, "pad %sactivation failed", active ? "" : "de");
2423 * gst_bin_recalculate_latency:
2426 * Query @bin for the current latency using and reconfigures this latency to all the
2427 * elements with a LATENCY event.
2429 * This method is typically called on the pipeline when a #GST_MESSAGE_LATENCY
2430 * is posted on the bus.
2432 * This function simply emits the 'do-latency' signal so any custom latency
2433 * calculations will be performed.
2435 * Returns: %TRUE if the latency could be queried and reconfigured.
2440 gst_bin_recalculate_latency (GstBin * bin)
2444 g_signal_emit (bin, gst_bin_signals[DO_LATENCY], 0, &res);
2445 GST_DEBUG_OBJECT (bin, "latency returned %d", res);
2451 gst_bin_do_latency_func (GstBin * bin)
2454 GstElement *element;
2455 GstClockTime min_latency, max_latency;
2458 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
2460 element = GST_ELEMENT_CAST (bin);
2462 GST_DEBUG_OBJECT (element, "querying latency");
2464 query = gst_query_new_latency ();
2465 if ((res = gst_element_query (element, query))) {
2468 gst_query_parse_latency (query, &live, &min_latency, &max_latency);
2470 GST_DEBUG_OBJECT (element,
2471 "got min latency %" GST_TIME_FORMAT ", max latency %"
2472 GST_TIME_FORMAT ", live %d", GST_TIME_ARGS (min_latency),
2473 GST_TIME_ARGS (max_latency), live);
2475 if (max_latency < min_latency) {
2476 /* this is an impossible situation, some parts of the pipeline might not
2477 * work correctly. We post a warning for now. */
2478 GST_ELEMENT_WARNING (element, CORE, CLOCK, (NULL),
2479 ("Impossible to configure latency: max %" GST_TIME_FORMAT " < min %"
2480 GST_TIME_FORMAT ". Add queues or other buffering elements.",
2481 GST_TIME_ARGS (max_latency), GST_TIME_ARGS (min_latency)));
2484 /* configure latency on elements */
2485 res = gst_element_send_event (element, gst_event_new_latency (min_latency));
2487 GST_INFO_OBJECT (element, "configured latency of %" GST_TIME_FORMAT,
2488 GST_TIME_ARGS (min_latency));
2490 GST_WARNING_OBJECT (element,
2491 "did not really configure latency of %" GST_TIME_FORMAT,
2492 GST_TIME_ARGS (min_latency));
2495 /* this is not a real problem, we just don't configure any latency. */
2496 GST_WARNING_OBJECT (element, "failed to query latency");
2498 gst_query_unref (query);
2504 gst_bin_state_changed (GstElement * element, GstState oldstate,
2505 GstState newstate, GstState pending)
2507 GstElementClass *pklass = (GstElementClass *) parent_class;
2509 if (newstate == GST_STATE_PLAYING && pending == GST_STATE_VOID_PENDING)
2510 bin_do_eos (GST_BIN_CAST (element));
2512 if (pklass->state_changed)
2513 pklass->state_changed (element, oldstate, newstate, pending);
2516 static GstStateChangeReturn
2517 gst_bin_change_state_func (GstElement * element, GstStateChange transition)
2520 GstStateChangeReturn ret;
2521 GstState current, next;
2522 gboolean have_async;
2523 gboolean have_no_preroll;
2524 GstClockTime base_time, start_time;
2527 GValue data = { 0, };
2529 /* we don't need to take the STATE_LOCK, it is already taken */
2530 current = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2531 next = (GstState) GST_STATE_TRANSITION_NEXT (transition);
2533 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2534 "changing state of children from %s to %s",
2535 gst_element_state_get_name (current), gst_element_state_get_name (next));
2537 bin = GST_BIN_CAST (element);
2540 case GST_STATE_PLAYING:
2544 GST_OBJECT_LOCK (bin);
2545 toplevel = BIN_IS_TOPLEVEL (bin);
2546 GST_OBJECT_UNLOCK (bin);
2549 gst_bin_recalculate_latency (bin);
2552 case GST_STATE_PAUSED:
2553 /* Clear EOS list on next PAUSED */
2554 GST_OBJECT_LOCK (bin);
2555 GST_DEBUG_OBJECT (element, "clearing EOS elements");
2556 bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
2557 bin->priv->posted_eos = FALSE;
2558 if (current == GST_STATE_READY)
2559 bin_remove_messages (bin, NULL, GST_MESSAGE_STREAM_START);
2560 GST_OBJECT_UNLOCK (bin);
2561 if (current == GST_STATE_READY)
2562 if (!(gst_bin_src_pads_activate (bin, TRUE)))
2563 goto activate_failure;
2565 case GST_STATE_READY:
2566 /* Clear message list on next READY */
2567 GST_OBJECT_LOCK (bin);
2568 GST_DEBUG_OBJECT (element, "clearing all cached messages");
2569 bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
2570 GST_OBJECT_UNLOCK (bin);
2571 if (current == GST_STATE_PAUSED)
2572 if (!(gst_bin_src_pads_activate (bin, FALSE)))
2573 goto activate_failure;
2575 case GST_STATE_NULL:
2576 if (current == GST_STATE_READY)
2577 if (!(gst_bin_src_pads_activate (bin, FALSE)))
2578 goto activate_failure;
2584 /* this flag is used to make the async state changes return immediately. We
2585 * don't want them to interfere with this state change */
2586 GST_OBJECT_LOCK (bin);
2587 bin->polling = TRUE;
2588 GST_OBJECT_UNLOCK (bin);
2590 /* iterate in state change order */
2591 it = gst_bin_iterate_sorted (bin);
2593 /* mark if we've seen an ASYNC element in the bin when we did a state change.
2594 * Note how we don't reset this value when a resync happens, the reason being
2595 * that the async element posted ASYNC_START and we want to post ASYNC_DONE
2596 * even after a resync when the async element is gone */
2600 /* take base_time */
2601 base_time = gst_element_get_base_time (element);
2602 start_time = gst_element_get_start_time (element);
2604 have_no_preroll = FALSE;
2608 switch (gst_iterator_next (it, &data)) {
2609 case GST_ITERATOR_OK:
2613 child = g_value_get_object (&data);
2615 /* set state and base_time now */
2616 ret = gst_bin_element_set_state (bin, child, base_time, start_time,
2620 case GST_STATE_CHANGE_SUCCESS:
2621 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2622 "child '%s' changed state to %d(%s) successfully",
2623 GST_ELEMENT_NAME (child), next,
2624 gst_element_state_get_name (next));
2626 case GST_STATE_CHANGE_ASYNC:
2628 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2629 "child '%s' is changing state asynchronously to %s",
2630 GST_ELEMENT_NAME (child), gst_element_state_get_name (next));
2634 case GST_STATE_CHANGE_FAILURE:{
2637 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2638 "child '%s' failed to go to state %d(%s)",
2639 GST_ELEMENT_NAME (child),
2640 next, gst_element_state_get_name (next));
2642 /* Only fail if the child is still inside
2643 * this bin. It might've been removed already
2644 * because of the error by the bin subclass
2645 * to ignore the error. */
2646 parent = gst_object_get_parent (GST_OBJECT_CAST (child));
2647 if (parent == GST_OBJECT_CAST (element)) {
2648 /* element is still in bin, really error now */
2649 gst_object_unref (parent);
2652 /* child removed from bin, let the resync code redo the state
2654 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2655 "child '%s' was removed from the bin",
2656 GST_ELEMENT_NAME (child));
2659 gst_object_unref (parent);
2663 case GST_STATE_CHANGE_NO_PREROLL:
2664 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2665 "child '%s' changed state to %d(%s) successfully without preroll",
2666 GST_ELEMENT_NAME (child), next,
2667 gst_element_state_get_name (next));
2668 have_no_preroll = TRUE;
2671 g_assert_not_reached ();
2674 g_value_reset (&data);
2677 case GST_ITERATOR_RESYNC:
2678 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "iterator doing resync");
2679 gst_iterator_resync (it);
2682 case GST_ITERATOR_DONE:
2683 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "iterator done");
2689 ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
2690 if (G_UNLIKELY (ret == GST_STATE_CHANGE_FAILURE))
2693 if (have_no_preroll) {
2694 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
2695 "we have NO_PREROLL elements %s -> NO_PREROLL",
2696 gst_element_state_change_return_get_name (ret));
2697 ret = GST_STATE_CHANGE_NO_PREROLL;
2698 } else if (have_async) {
2699 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
2700 "we have ASYNC elements %s -> ASYNC",
2701 gst_element_state_change_return_get_name (ret));
2702 ret = GST_STATE_CHANGE_ASYNC;
2706 g_value_unset (&data);
2707 gst_iterator_free (it);
2709 GST_OBJECT_LOCK (bin);
2710 bin->polling = FALSE;
2711 /* it's possible that we did not get ASYNC from the children while the bin is
2712 * simulating ASYNC behaviour by posting an ASYNC_DONE message on the bus with
2713 * itself as the source. In that case we still want to check if the state
2714 * change completed. */
2715 if (ret != GST_STATE_CHANGE_ASYNC && !bin->priv->pending_async_done) {
2716 /* no element returned ASYNC and there are no pending async_done messages,
2717 * we can just complete. */
2718 GST_DEBUG_OBJECT (bin, "no async elements");
2721 /* when we get here an ASYNC element was found */
2722 if (GST_STATE_TARGET (bin) <= GST_STATE_READY) {
2723 /* we ignore ASYNC state changes when we go to READY or NULL */
2724 GST_DEBUG_OBJECT (bin, "target state %s <= READY",
2725 gst_element_state_get_name (GST_STATE_TARGET (bin)));
2729 GST_DEBUG_OBJECT (bin, "check async elements");
2730 /* check if all elements managed to commit their state already */
2731 if (!find_message (bin, NULL, GST_MESSAGE_ASYNC_START)) {
2732 /* nothing found, remove all old ASYNC_DONE messages. This can happen when
2733 * all the elements commited their state while we were doing the state
2734 * change. We will still return ASYNC for consistency but we commit the
2735 * state already so that a _get_state() will return immediately. */
2736 bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
2738 GST_DEBUG_OBJECT (bin, "async elements commited");
2739 bin_handle_async_done (bin, GST_STATE_CHANGE_SUCCESS, FALSE,
2740 GST_CLOCK_TIME_NONE);
2744 bin->priv->pending_async_done = FALSE;
2745 GST_OBJECT_UNLOCK (bin);
2747 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2748 "done changing bin's state from %s to %s, now in %s, ret %s",
2749 gst_element_state_get_name (current),
2750 gst_element_state_get_name (next),
2751 gst_element_state_get_name (GST_STATE (element)),
2752 gst_element_state_change_return_get_name (ret));
2759 GST_CAT_WARNING_OBJECT (GST_CAT_STATES, element,
2760 "failure (de)activating src pads");
2761 return GST_STATE_CHANGE_FAILURE;
2766 * This function is a utility event handler for seek events.
2767 * It will send the event to all sinks or sources depending on the
2770 * Applications are free to override this behaviour and
2771 * implement their own seek handler, but this will work for
2772 * pretty much all cases in practice.
2775 gst_bin_send_event (GstElement * element, GstEvent * event)
2777 GstBin *bin = GST_BIN_CAST (element);
2779 gboolean res = TRUE;
2780 gboolean done = FALSE;
2781 GValue data = { 0, };
2783 if (GST_EVENT_IS_DOWNSTREAM (event)) {
2784 iter = gst_bin_iterate_sources (bin);
2785 GST_DEBUG_OBJECT (bin, "Sending %s event to src children",
2786 GST_EVENT_TYPE_NAME (event));
2788 iter = gst_bin_iterate_sinks (bin);
2789 GST_DEBUG_OBJECT (bin, "Sending %s event to sink children",
2790 GST_EVENT_TYPE_NAME (event));
2794 switch (gst_iterator_next (iter, &data)) {
2795 case GST_ITERATOR_OK:
2797 GstElement *child = g_value_get_object (&data);;
2799 gst_event_ref (event);
2800 res &= gst_element_send_event (child, event);
2801 GST_LOG_OBJECT (child, "After handling %s event: %d",
2802 GST_EVENT_TYPE_NAME (event), res);
2805 case GST_ITERATOR_RESYNC:
2806 gst_iterator_resync (iter);
2809 case GST_ITERATOR_DONE:
2812 case GST_ITERATOR_ERROR:
2813 g_assert_not_reached ();
2817 g_value_unset (&data);
2818 gst_iterator_free (iter);
2819 gst_event_unref (event);
2824 /* this is the function called by the threadpool. When async elements commit
2825 * their state, this function will attempt to bring the bin to the next state.
2828 gst_bin_continue_func (BinContinueData * data)
2831 GstState current, next, pending;
2832 GstStateChange transition;
2835 pending = data->pending;
2837 GST_DEBUG_OBJECT (bin, "waiting for state lock");
2838 GST_STATE_LOCK (bin);
2840 GST_DEBUG_OBJECT (bin, "doing state continue");
2841 GST_OBJECT_LOCK (bin);
2843 /* if a new state change happened after this thread was scheduled, we return
2845 if (data->cookie != GST_ELEMENT_CAST (bin)->state_cookie)
2848 current = GST_STATE (bin);
2849 next = GST_STATE_GET_NEXT (current, pending);
2850 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2852 GST_STATE_NEXT (bin) = next;
2853 GST_STATE_PENDING (bin) = pending;
2855 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
2856 GST_OBJECT_UNLOCK (bin);
2858 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
2859 "continue state change %s to %s, final %s",
2860 gst_element_state_get_name (current),
2861 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2863 gst_element_change_state (GST_ELEMENT_CAST (bin), transition);
2865 GST_STATE_UNLOCK (bin);
2866 GST_DEBUG_OBJECT (bin, "state continue done");
2868 gst_object_unref (bin);
2869 g_slice_free (BinContinueData, data);
2874 GST_OBJECT_UNLOCK (bin);
2875 GST_STATE_UNLOCK (bin);
2876 GST_DEBUG_OBJECT (bin, "state continue aborted due to intervening change");
2877 gst_object_unref (bin);
2878 g_slice_free (BinContinueData, data);
2883 static GstBusSyncReply
2884 bin_bus_handler (GstBus * bus, GstMessage * message, GstBin * bin)
2886 GstBinClass *bclass;
2888 bclass = GST_BIN_GET_CLASS (bin);
2889 if (bclass->handle_message)
2890 bclass->handle_message (bin, message);
2892 gst_message_unref (message);
2894 return GST_BUS_DROP;
2898 bin_push_state_continue (BinContinueData * data)
2905 klass = GST_BIN_GET_CLASS (bin);
2907 GST_DEBUG_OBJECT (bin, "pushing continue on thread pool");
2908 g_thread_pool_push (klass->pool, data, NULL);
2911 /* an element started an async state change, if we were not busy with a state
2912 * change, we perform a lost state.
2913 * This function is called with the OBJECT lock.
2916 bin_handle_async_start (GstBin * bin)
2918 GstState old_state, new_state;
2920 GstMessage *amessage = NULL;
2922 if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
2925 /* get our toplevel state */
2926 toplevel = BIN_IS_TOPLEVEL (bin);
2928 /* prepare an ASYNC_START message, we always post the start message even if we
2929 * are busy with a state change or when we are NO_PREROLL. */
2931 /* non toplevel bin, prepare async-start for the parent */
2932 amessage = gst_message_new_async_start (GST_OBJECT_CAST (bin));
2934 if (bin->polling || GST_STATE_PENDING (bin) != GST_STATE_VOID_PENDING)
2937 /* async starts are ignored when we are NO_PREROLL */
2938 if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_NO_PREROLL)
2939 goto was_no_preroll;
2941 old_state = GST_STATE (bin);
2943 /* when we PLAYING we go back to PAUSED, when preroll happens, we go back to
2944 * PLAYING after optionally redistributing the base_time. */
2945 if (old_state > GST_STATE_PAUSED)
2946 new_state = GST_STATE_PAUSED;
2948 new_state = old_state;
2950 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
2951 "lost state of %s, new %s", gst_element_state_get_name (old_state),
2952 gst_element_state_get_name (new_state));
2954 GST_STATE (bin) = new_state;
2955 GST_STATE_NEXT (bin) = new_state;
2956 GST_STATE_PENDING (bin) = new_state;
2957 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
2958 GST_OBJECT_UNLOCK (bin);
2961 _priv_gst_element_state_changed (GST_ELEMENT_CAST (bin), new_state, new_state,
2966 /* post our ASYNC_START. */
2967 GST_DEBUG_OBJECT (bin, "posting ASYNC_START to parent");
2968 gst_element_post_message (GST_ELEMENT_CAST (bin), amessage);
2970 GST_OBJECT_LOCK (bin);
2976 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
2981 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
2982 GST_OBJECT_UNLOCK (bin);
2987 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "ignoring, we are NO_PREROLL");
2988 GST_OBJECT_UNLOCK (bin);
2993 /* this function is called when there are no more async elements in the bin. We
2994 * post a state changed message and an ASYNC_DONE message.
2995 * This function is called with the OBJECT lock.
2998 bin_handle_async_done (GstBin * bin, GstStateChangeReturn ret,
2999 gboolean flag_pending, GstClockTime running_time)
3001 GstState current, pending, target;
3002 GstStateChangeReturn old_ret;
3003 GstState old_state, old_next;
3004 gboolean toplevel, state_changed = FALSE;
3005 GstMessage *amessage = NULL;
3006 BinContinueData *cont = NULL;
3008 if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
3011 pending = GST_STATE_PENDING (bin);
3016 /* check if there is something to commit */
3017 if (pending == GST_STATE_VOID_PENDING)
3018 goto nothing_pending;
3020 old_ret = GST_STATE_RETURN (bin);
3021 GST_STATE_RETURN (bin) = ret;
3023 /* move to the next target state */
3024 target = GST_STATE_TARGET (bin);
3025 pending = GST_STATE_PENDING (bin) = target;
3027 amessage = gst_message_new_async_done (GST_OBJECT_CAST (bin), running_time);
3029 old_state = GST_STATE (bin);
3030 /* this is the state we should go to next */
3031 old_next = GST_STATE_NEXT (bin);
3033 if (old_next != GST_STATE_PLAYING) {
3034 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3035 "committing state from %s to %s, old pending %s",
3036 gst_element_state_get_name (old_state),
3037 gst_element_state_get_name (old_next),
3038 gst_element_state_get_name (pending));
3040 /* update current state */
3041 current = GST_STATE (bin) = old_next;
3043 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3044 "setting state from %s to %s, pending %s",
3045 gst_element_state_get_name (old_state),
3046 gst_element_state_get_name (old_state),
3047 gst_element_state_get_name (pending));
3048 current = old_state;
3051 /* get our toplevel state */
3052 toplevel = BIN_IS_TOPLEVEL (bin);
3054 /* see if we reached the final state. If we are not toplevel, we also have to
3055 * stop here, the parent will continue our state. */
3056 if ((pending == current) || !toplevel) {
3057 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3058 "completed state change, pending VOID");
3060 /* mark VOID pending */
3061 pending = GST_STATE_VOID_PENDING;
3062 GST_STATE_PENDING (bin) = pending;
3063 GST_STATE_NEXT (bin) = GST_STATE_VOID_PENDING;
3065 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3066 "continue state change, pending %s",
3067 gst_element_state_get_name (pending));
3069 cont = g_slice_new (BinContinueData);
3071 /* ref to the bin */
3072 cont->bin = gst_object_ref (bin);
3073 /* cookie to detect concurrent state change */
3074 cont->cookie = GST_ELEMENT_CAST (bin)->state_cookie;
3075 /* pending target state */
3076 cont->pending = pending;
3078 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
3079 GST_STATE_NEXT (bin) = GST_STATE_GET_NEXT (old_state, pending);
3082 if (old_next != GST_STATE_PLAYING) {
3083 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
3084 state_changed = TRUE;
3087 GST_OBJECT_UNLOCK (bin);
3089 if (state_changed) {
3090 _priv_gst_element_state_changed (GST_ELEMENT_CAST (bin), old_state,
3094 /* post our combined ASYNC_DONE when all is ASYNC_DONE. */
3095 GST_DEBUG_OBJECT (bin, "posting ASYNC_DONE to parent");
3096 gst_element_post_message (GST_ELEMENT_CAST (bin), amessage);
3099 GST_OBJECT_LOCK (bin);
3101 /* toplevel, start continue state */
3102 GST_DEBUG_OBJECT (bin, "all async-done, starting state continue");
3103 bin_push_state_continue (cont);
3105 GST_DEBUG_OBJECT (bin, "state change complete");
3106 GST_STATE_BROADCAST (bin);
3112 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
3117 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
3118 /* if we were busy with a state change and we are requested to flag a
3119 * pending async done, we do so here */
3121 bin->priv->pending_async_done = TRUE;
3126 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "nothing pending");
3132 bin_do_eos (GstBin * bin)
3137 GST_OBJECT_LOCK (bin);
3138 /* If all sinks are EOS, we're in PLAYING and no state change is pending
3139 * we forward the EOS message to the parent bin or application
3141 eos = GST_STATE (bin) == GST_STATE_PLAYING
3142 && GST_STATE_PENDING (bin) == GST_STATE_VOID_PENDING
3143 && is_eos (bin, &seqnum);
3144 GST_OBJECT_UNLOCK (bin);
3147 && g_atomic_int_compare_and_exchange (&bin->priv->posted_eos, FALSE,
3149 GstMessage *tmessage;
3151 /* Clear out any further messages, and reset posted_eos so we can
3152 detect any new EOS that happens (eg, after a seek). Since all
3153 sinks have now posted an EOS, there will be no further EOS events
3154 seen unless there is a new logical EOS */
3155 GST_OBJECT_LOCK (bin);
3156 bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
3157 bin->priv->posted_eos = FALSE;
3158 GST_OBJECT_UNLOCK (bin);
3160 tmessage = gst_message_new_eos (GST_OBJECT_CAST (bin));
3161 gst_message_set_seqnum (tmessage, seqnum);
3162 GST_DEBUG_OBJECT (bin,
3163 "all sinks posted EOS, posting seqnum #%" G_GUINT32_FORMAT, seqnum);
3164 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3169 bin_do_stream_start (GstBin * bin)
3172 gboolean stream_start;
3174 GST_OBJECT_LOCK (bin);
3175 /* If all sinks are STREAM_START we forward the STREAM_START message
3176 * to the parent bin or application
3178 stream_start = is_stream_start (bin, &seqnum);
3179 GST_OBJECT_UNLOCK (bin);
3182 GstMessage *tmessage;
3184 GST_OBJECT_LOCK (bin);
3185 bin_remove_messages (bin, NULL, GST_MESSAGE_STREAM_START);
3186 GST_OBJECT_UNLOCK (bin);
3188 tmessage = gst_message_new_stream_start (GST_OBJECT_CAST (bin));
3189 gst_message_set_seqnum (tmessage, seqnum);
3190 GST_DEBUG_OBJECT (bin,
3191 "all sinks posted STREAM_START, posting seqnum #%" G_GUINT32_FORMAT,
3193 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3197 /* must be called with the object lock. This function releases the lock to post
3200 bin_do_message_forward (GstBin * bin, GstMessage * message)
3202 if (bin->priv->message_forward) {
3203 GstMessage *forwarded;
3205 GST_DEBUG_OBJECT (bin, "pass %s message upward",
3206 GST_MESSAGE_TYPE_NAME (message));
3207 GST_OBJECT_UNLOCK (bin);
3209 /* we need to convert these messages to element messages so that our parent
3210 * bin can easily ignore them and so that the application can easily
3211 * distinguish between the internally forwarded and the real messages. */
3212 forwarded = gst_message_new_element (GST_OBJECT_CAST (bin),
3213 gst_structure_new ("GstBinForwarded",
3214 "message", GST_TYPE_MESSAGE, message, NULL));
3216 gst_element_post_message (GST_ELEMENT_CAST (bin), forwarded);
3218 GST_OBJECT_LOCK (bin);
3222 /* handle child messages:
3224 * This method is called synchronously when a child posts a message on
3227 * GST_MESSAGE_EOS: This message is only posted by sinks
3228 * in the PLAYING state. If all sinks posted the EOS message, post
3231 * GST_MESSAGE_STATE_DIRTY: Deprecated
3233 * GST_MESSAGE_SEGMENT_START: just collect, never forward upwards. If an
3234 * element posts segment_start twice, only the last message is kept.
3236 * GST_MESSAGE_SEGMENT_DONE: replace SEGMENT_START message from same poster
3237 * with the segment_done message. If there are no more segment_start
3238 * messages, post segment_done message upwards.
3240 * GST_MESSAGE_DURATION: remove all previously cached duration messages.
3241 * Whenever someone performs a duration query on the bin, we store the
3242 * result so we can answer it quicker the next time. Any element that
3243 * changes its duration marks our cached values invalid.
3244 * This message is also posted upwards. This is currently disabled
3245 * because too many elements don't post DURATION messages when the
3248 * GST_MESSAGE_CLOCK_LOST: This message is posted by an element when it
3249 * can no longer provide a clock. The default bin behaviour is to
3250 * check if the lost clock was the one provided by the bin. If so and
3251 * we are currently in the PLAYING state, we forward the message to
3253 * This message is also generated when we remove a clock provider from
3254 * a bin. If this message is received by the application, it should
3255 * PAUSE the pipeline and set it back to PLAYING to force a new clock
3256 * and a new base_time distribution.
3258 * GST_MESSAGE_CLOCK_PROVIDE: This message is generated when an element
3259 * can provide a clock. This mostly happens when we add a new clock
3260 * provider to the bin. The default behaviour of the bin is to mark the
3261 * currently selected clock as dirty, which will perform a clock
3262 * recalculation the next time we are asked to provide a clock.
3263 * This message is never sent to the application but is forwarded to
3266 * GST_MESSAGE_ASYNC_START: Create an internal ELEMENT message that stores
3267 * the state of the element and the fact that the element will need a
3268 * new base_time. This message is not forwarded to the application.
3270 * GST_MESSAGE_ASYNC_DONE: Find the internal ELEMENT message we kept for the
3271 * element when it posted ASYNC_START. If all elements are done, post a
3272 * ASYNC_DONE message to the parent.
3274 * OTHER: post upwards.
3277 gst_bin_handle_message_func (GstBin * bin, GstMessage * message)
3280 GstMessageType type;
3281 GstMessage *tmessage;
3284 src = GST_MESSAGE_SRC (message);
3285 type = GST_MESSAGE_TYPE (message);
3287 GST_DEBUG_OBJECT (bin, "[msg %p] handling child %s message of type %s",
3288 message, src ? GST_ELEMENT_NAME (src) : "(NULL)",
3289 GST_MESSAGE_TYPE_NAME (message));
3292 case GST_MESSAGE_ERROR:
3294 GST_OBJECT_LOCK (bin);
3296 GST_DEBUG_OBJECT (bin, "got ERROR message, unlocking state change");
3297 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_FAILURE;
3298 GST_STATE_BROADCAST (bin);
3299 GST_OBJECT_UNLOCK (bin);
3303 case GST_MESSAGE_EOS:
3306 /* collect all eos messages from the children */
3307 GST_OBJECT_LOCK (bin);
3308 bin_do_message_forward (bin, message);
3309 /* ref message for future use */
3310 bin_replace_message (bin, message, GST_MESSAGE_EOS);
3311 GST_OBJECT_UNLOCK (bin);
3316 case GST_MESSAGE_STREAM_START:
3319 /* collect all stream_start messages from the children */
3320 GST_OBJECT_LOCK (bin);
3321 /* ref message for future use */
3322 bin_replace_message (bin, message, GST_MESSAGE_STREAM_START);
3323 GST_OBJECT_UNLOCK (bin);
3325 bin_do_stream_start (bin);
3328 case GST_MESSAGE_STATE_DIRTY:
3330 GST_WARNING_OBJECT (bin, "received deprecated STATE_DIRTY message");
3333 gst_message_unref (message);
3336 case GST_MESSAGE_SEGMENT_START:{
3337 gboolean post = FALSE;
3341 gst_message_parse_segment_start (message, &format, &position);
3342 seqnum = gst_message_get_seqnum (message);
3344 GST_OBJECT_LOCK (bin);
3345 bin_do_message_forward (bin, message);
3346 /* if this is the first segment-start, post to parent but not to the
3348 if (!find_message (bin, NULL, GST_MESSAGE_SEGMENT_START) &&
3349 (GST_OBJECT_PARENT (bin) != NULL)) {
3352 /* replace any previous segment_start message from this source
3353 * with the new segment start message */
3354 bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
3355 GST_OBJECT_UNLOCK (bin);
3357 tmessage = gst_message_new_segment_start (GST_OBJECT_CAST (bin),
3359 gst_message_set_seqnum (tmessage, seqnum);
3361 /* post segment start with initial format and position. */
3362 GST_DEBUG_OBJECT (bin, "posting SEGMENT_START (%u) bus message: %p",
3364 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3368 case GST_MESSAGE_SEGMENT_DONE:
3370 gboolean post = FALSE;
3374 gst_message_parse_segment_done (message, &format, &position);
3375 seqnum = gst_message_get_seqnum (message);
3377 GST_OBJECT_LOCK (bin);
3378 bin_do_message_forward (bin, message);
3379 bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
3380 /* if there are no more segment_start messages, everybody posted
3381 * a segment_done and we can post one on the bus. */
3383 /* we don't care who still has a pending segment start */
3384 if (!find_message (bin, NULL, GST_MESSAGE_SEGMENT_START)) {
3387 /* remove all old segment_done messages */
3388 bin_remove_messages (bin, NULL, GST_MESSAGE_SEGMENT_DONE);
3390 GST_OBJECT_UNLOCK (bin);
3392 tmessage = gst_message_new_segment_done (GST_OBJECT_CAST (bin),
3394 gst_message_set_seqnum (tmessage, seqnum);
3396 /* post segment done with latest format and position. */
3397 GST_DEBUG_OBJECT (bin, "posting SEGMENT_DONE (%u) bus message: %p",
3399 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3403 case GST_MESSAGE_DURATION:
3405 /* remove all cached duration messages, next time somebody asks
3406 * for duration, we will recalculate. */
3407 GST_OBJECT_LOCK (bin);
3408 bin_remove_messages (bin, NULL, GST_MESSAGE_DURATION);
3409 GST_OBJECT_UNLOCK (bin);
3412 case GST_MESSAGE_CLOCK_LOST:
3414 GstClock **provided_clock_p;
3415 GstElement **clock_provider_p;
3416 gboolean playing, provided, forward;
3419 gst_message_parse_clock_lost (message, &clock);
3421 GST_OBJECT_LOCK (bin);
3422 bin->clock_dirty = TRUE;
3423 /* if we lost the clock that we provided, post to parent but
3424 * only if we are PLAYING. */
3425 provided = (clock == bin->provided_clock);
3426 playing = (GST_STATE (bin) == GST_STATE_PLAYING);
3427 forward = playing & provided;
3429 GST_DEBUG_OBJECT (bin,
3430 "Lost clock %" GST_PTR_FORMAT " provided by %" GST_PTR_FORMAT,
3431 bin->provided_clock, bin->clock_provider);
3432 provided_clock_p = &bin->provided_clock;
3433 clock_provider_p = &bin->clock_provider;
3434 gst_object_replace ((GstObject **) provided_clock_p, NULL);
3435 gst_object_replace ((GstObject **) clock_provider_p, NULL);
3437 GST_DEBUG_OBJECT (bin, "provided %d, playing %d, forward %d",
3438 provided, playing, forward);
3439 GST_OBJECT_UNLOCK (bin);
3445 gst_message_unref (message);
3448 case GST_MESSAGE_CLOCK_PROVIDE:
3452 GST_OBJECT_LOCK (bin);
3453 bin->clock_dirty = TRUE;
3454 /* a new clock is available, post to parent but not
3455 * to the application */
3456 forward = GST_OBJECT_PARENT (bin) != NULL;
3457 GST_OBJECT_UNLOCK (bin);
3463 gst_message_unref (message);
3466 case GST_MESSAGE_ASYNC_START:
3470 GST_DEBUG_OBJECT (bin, "ASYNC_START message %p, %s", message,
3471 src ? GST_OBJECT_NAME (src) : "(NULL)");
3473 GST_OBJECT_LOCK (bin);
3474 bin_do_message_forward (bin, message);
3476 /* we ignore the message if we are going to <= READY */
3477 if ((target = GST_STATE_TARGET (bin)) <= GST_STATE_READY)
3478 goto ignore_start_message;
3480 /* takes ownership of the message */
3481 bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
3483 bin_handle_async_start (bin);
3484 GST_OBJECT_UNLOCK (bin);
3487 ignore_start_message:
3489 GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
3490 gst_element_state_get_name (target));
3491 GST_OBJECT_UNLOCK (bin);
3492 gst_message_unref (message);
3496 case GST_MESSAGE_ASYNC_DONE:
3498 GstClockTime running_time;
3501 GST_DEBUG_OBJECT (bin, "ASYNC_DONE message %p, %s", message,
3502 src ? GST_OBJECT_NAME (src) : "(NULL)");
3504 gst_message_parse_async_done (message, &running_time);
3506 GST_OBJECT_LOCK (bin);
3507 bin_do_message_forward (bin, message);
3509 /* ignore messages if we are shutting down */
3510 if ((target = GST_STATE_TARGET (bin)) <= GST_STATE_READY)
3511 goto ignore_done_message;
3513 bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
3514 /* if there are no more ASYNC_START messages, everybody posted
3515 * a ASYNC_DONE and we can post one on the bus. When checking, we
3516 * don't care who still has a pending ASYNC_START */
3517 if (!find_message (bin, NULL, GST_MESSAGE_ASYNC_START)) {
3518 /* nothing found, remove all old ASYNC_DONE messages */
3519 bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
3521 GST_DEBUG_OBJECT (bin, "async elements commited");
3522 /* when we get an async done message when a state change was busy, we
3523 * need to set the pending_done flag so that at the end of the state
3524 * change we can see if we need to verify pending async elements, hence
3525 * the TRUE argument here. */
3526 bin_handle_async_done (bin, GST_STATE_CHANGE_SUCCESS, TRUE,
3529 GST_DEBUG_OBJECT (bin, "there are more async elements pending");
3531 GST_OBJECT_UNLOCK (bin);
3534 ignore_done_message:
3536 GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
3537 gst_element_state_get_name (target));
3538 GST_OBJECT_UNLOCK (bin);
3539 gst_message_unref (message);
3543 case GST_MESSAGE_STRUCTURE_CHANGE:
3547 gst_message_parse_structure_change (message, NULL, NULL, &busy);
3549 GST_OBJECT_LOCK (bin);
3551 /* while the pad is busy, avoid following it when doing state changes.
3552 * Don't update the cookie yet, we will do that after the structure
3553 * change finished and we are ready to inspect the new updated
3555 bin_replace_message (bin, message, GST_MESSAGE_STRUCTURE_CHANGE);
3558 /* a pad link/unlink ended, signal the state change iterator that we
3559 * need to resync by updating the structure_cookie. */
3560 bin_remove_messages (bin, GST_MESSAGE_SRC (message),
3561 GST_MESSAGE_STRUCTURE_CHANGE);
3562 bin->priv->structure_cookie++;
3564 GST_OBJECT_UNLOCK (bin);
3567 gst_message_unref (message);
3578 /* Send all other messages upward */
3579 GST_DEBUG_OBJECT (bin, "posting message upward");
3580 gst_element_post_message (GST_ELEMENT_CAST (bin), message);
3585 /* generic struct passed to all query fold methods */
3594 typedef void (*QueryInitFunction) (GstBin * bin, QueryFold * fold);
3595 typedef void (*QueryDoneFunction) (GstBin * bin, QueryFold * fold);
3597 /* for duration/position we collect all durations/positions and take
3598 * the MAX of all valid results */
3600 bin_query_min_max_init (GstBin * bin, QueryFold * fold)
3608 bin_query_duration_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3610 GstElement *item = g_value_get_object (vitem);
3612 if (gst_element_query (item, fold->query)) {
3615 g_value_set_boolean (ret, TRUE);
3617 gst_query_parse_duration (fold->query, NULL, &duration);
3619 GST_DEBUG_OBJECT (item, "got duration %" G_GINT64_FORMAT, duration);
3621 if (duration > fold->max)
3622 fold->max = duration;
3629 bin_query_duration_done (GstBin * bin, QueryFold * fold)
3633 gst_query_parse_duration (fold->query, &format, NULL);
3634 /* store max in query result */
3635 gst_query_set_duration (fold->query, format, fold->max);
3637 GST_DEBUG_OBJECT (bin, "max duration %" G_GINT64_FORMAT, fold->max);
3640 GST_OBJECT_LOCK (bin);
3641 bin->messages = g_list_prepend (bin->messages,
3642 gst_message_new_duration (GST_OBJECT_CAST (bin), format, fold->max));
3643 GST_OBJECT_UNLOCK (bin);
3647 bin_query_position_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3649 GstElement *item = g_value_get_object (vitem);
3651 if (gst_element_query (item, fold->query)) {
3654 g_value_set_boolean (ret, TRUE);
3656 gst_query_parse_position (fold->query, NULL, &position);
3658 GST_DEBUG_OBJECT (item, "got position %" G_GINT64_FORMAT, position);
3660 if (position > fold->max)
3661 fold->max = position;
3668 bin_query_position_done (GstBin * bin, QueryFold * fold)
3672 gst_query_parse_position (fold->query, &format, NULL);
3673 /* store max in query result */
3674 gst_query_set_position (fold->query, format, fold->max);
3676 GST_DEBUG_OBJECT (bin, "max position %" G_GINT64_FORMAT, fold->max);
3680 bin_query_latency_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3682 GstElement *item = g_value_get_object (vitem);
3684 if (gst_element_query (item, fold->query)) {
3685 GstClockTime min, max;
3688 gst_query_parse_latency (fold->query, &live, &min, &max);
3690 GST_DEBUG_OBJECT (item,
3691 "got latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
3692 ", live %d", GST_TIME_ARGS (min), GST_TIME_ARGS (max), live);
3694 /* for the combined latency we collect the MAX of all min latencies and
3695 * the MIN of all max latencies */
3697 if (min > fold->min)
3699 if (fold->max == -1)
3701 else if (max < fold->max)
3703 if (fold->live == FALSE)
3707 g_value_set_boolean (ret, FALSE);
3708 GST_DEBUG_OBJECT (item, "failed query");
3715 bin_query_latency_done (GstBin * bin, QueryFold * fold)
3717 /* store max in query result */
3718 gst_query_set_latency (fold->query, fold->live, fold->min, fold->max);
3720 GST_DEBUG_OBJECT (bin,
3721 "latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
3722 ", live %d", GST_TIME_ARGS (fold->min), GST_TIME_ARGS (fold->max),
3726 /* generic fold, return first valid result */
3728 bin_query_generic_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3730 GstElement *item = g_value_get_object (vitem);
3733 if ((res = gst_element_query (item, fold->query))) {
3734 g_value_set_boolean (ret, TRUE);
3735 GST_DEBUG_OBJECT (item, "answered query %p", fold->query);
3738 /* and stop as soon as we have a valid result */
3743 gst_bin_query (GstElement * element, GstQuery * query)
3745 GstBin *bin = GST_BIN_CAST (element);
3747 gboolean res = FALSE;
3748 GstIteratorFoldFunction fold_func;
3749 QueryInitFunction fold_init = NULL;
3750 QueryDoneFunction fold_done = NULL;
3751 QueryFold fold_data;
3754 switch (GST_QUERY_TYPE (query)) {
3755 case GST_QUERY_DURATION:
3760 gst_query_parse_duration (query, &qformat, NULL);
3762 /* find cached duration query */
3763 GST_OBJECT_LOCK (bin);
3764 for (cached = bin->messages; cached; cached = g_list_next (cached)) {
3765 GstMessage *message = (GstMessage *) cached->data;
3767 if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_DURATION &&
3768 GST_MESSAGE_SRC (message) == GST_OBJECT_CAST (bin)) {
3772 gst_message_parse_duration (message, &format, &duration);
3774 /* if cached same format, copy duration in query result */
3775 if (format == qformat) {
3776 GST_DEBUG_OBJECT (bin, "return cached duration %" G_GINT64_FORMAT,
3778 GST_OBJECT_UNLOCK (bin);
3780 gst_query_set_duration (query, qformat, duration);
3786 GST_OBJECT_UNLOCK (bin);
3787 /* no cached value found, iterate and collect durations */
3788 fold_func = (GstIteratorFoldFunction) bin_query_duration_fold;
3789 fold_init = bin_query_min_max_init;
3790 fold_done = bin_query_duration_done;
3793 case GST_QUERY_POSITION:
3795 fold_func = (GstIteratorFoldFunction) bin_query_position_fold;
3796 fold_init = bin_query_min_max_init;
3797 fold_done = bin_query_position_done;
3800 case GST_QUERY_LATENCY:
3802 fold_func = (GstIteratorFoldFunction) bin_query_latency_fold;
3803 fold_init = bin_query_min_max_init;
3804 fold_done = bin_query_latency_done;
3809 fold_func = (GstIteratorFoldFunction) bin_query_generic_fold;
3813 fold_data.query = query;
3815 /* set the result of the query to FALSE initially */
3816 g_value_init (&ret, G_TYPE_BOOLEAN);
3817 g_value_set_boolean (&ret, res);
3819 iter = gst_bin_iterate_sinks (bin);
3820 GST_DEBUG_OBJECT (bin, "Sending query %p (type %s) to sink children",
3821 query, GST_QUERY_TYPE_NAME (query));
3824 fold_init (bin, &fold_data);
3827 GstIteratorResult ires;
3829 ires = gst_iterator_fold (iter, fold_func, &ret, &fold_data);
3832 case GST_ITERATOR_RESYNC:
3833 gst_iterator_resync (iter);
3835 fold_init (bin, &fold_data);
3836 g_value_set_boolean (&ret, res);
3838 case GST_ITERATOR_OK:
3839 case GST_ITERATOR_DONE:
3840 res = g_value_get_boolean (&ret);
3841 if (fold_done != NULL && res)
3842 fold_done (bin, &fold_data);
3850 gst_iterator_free (iter);
3853 GST_DEBUG_OBJECT (bin, "query %p result %d", query, res);
3859 compare_name (const GValue * velement, const gchar * name)
3862 GstElement *element = g_value_get_object (velement);
3864 GST_OBJECT_LOCK (element);
3865 eq = strcmp (GST_ELEMENT_NAME (element), name);
3866 GST_OBJECT_UNLOCK (element);
3872 * gst_bin_get_by_name:
3874 * @name: the element name to search for
3876 * Gets the element with the given name from a bin. This
3877 * function recurses into child bins.
3879 * Returns NULL if no element with the given name is found in the bin.
3881 * MT safe. Caller owns returned reference.
3883 * Returns: (transfer full): the #GstElement with the given name, or NULL
3886 gst_bin_get_by_name (GstBin * bin, const gchar * name)
3888 GstIterator *children;
3889 GValue result = { 0, };
3890 GstElement *element;
3893 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
3895 GST_CAT_INFO (GST_CAT_PARENTAGE, "[%s]: looking up child element %s",
3896 GST_ELEMENT_NAME (bin), name);
3898 children = gst_bin_iterate_recurse (bin);
3899 found = gst_iterator_find_custom (children,
3900 (GCompareFunc) compare_name, &result, (gpointer) name);
3901 gst_iterator_free (children);
3904 element = g_value_dup_object (&result);
3905 g_value_unset (&result);
3914 * gst_bin_get_by_name_recurse_up:
3916 * @name: the element name to search for
3918 * Gets the element with the given name from this bin. If the
3919 * element is not found, a recursion is performed on the parent bin.
3922 * - no element with the given name is found in the bin
3924 * MT safe. Caller owns returned reference.
3926 * Returns: (transfer full): the #GstElement with the given name, or NULL
3929 gst_bin_get_by_name_recurse_up (GstBin * bin, const gchar * name)
3933 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
3934 g_return_val_if_fail (name != NULL, NULL);
3936 result = gst_bin_get_by_name (bin, name);
3941 parent = gst_object_get_parent (GST_OBJECT_CAST (bin));
3943 if (GST_IS_BIN (parent)) {
3944 result = gst_bin_get_by_name_recurse_up (GST_BIN_CAST (parent), name);
3946 gst_object_unref (parent);
3954 compare_interface (const GValue * velement, GValue * interface)
3956 GstElement *element = g_value_get_object (velement);
3957 GType interface_type = (GType) g_value_get_pointer (interface);
3960 if (G_TYPE_CHECK_INSTANCE_TYPE (element, interface_type)) {
3969 * gst_bin_get_by_interface:
3971 * @iface: the #GType of an interface
3973 * Looks for an element inside the bin that implements the given
3974 * interface. If such an element is found, it returns the element.
3975 * You can cast this element to the given interface afterwards. If you want
3976 * all elements that implement the interface, use
3977 * gst_bin_iterate_all_by_interface(). This function recurses into child bins.
3979 * MT safe. Caller owns returned reference.
3981 * Returns: (transfer full): A #GstElement inside the bin implementing the interface
3984 gst_bin_get_by_interface (GstBin * bin, GType iface)
3986 GstIterator *children;
3987 GValue result = { 0, };
3988 GstElement *element;
3990 GValue viface = { 0, };
3992 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
3993 g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
3995 g_value_init (&viface, G_TYPE_POINTER);
3996 g_value_set_pointer (&viface, (gpointer) iface);
3998 children = gst_bin_iterate_recurse (bin);
3999 found = gst_iterator_find_custom (children, (GCompareFunc) compare_interface,
4001 gst_iterator_free (children);
4004 element = g_value_dup_object (&result);
4005 g_value_unset (&result);
4009 g_value_unset (&viface);
4015 * gst_bin_iterate_all_by_interface:
4017 * @iface: the #GType of an interface
4019 * Looks for all elements inside the bin that implements the given
4020 * interface. You can safely cast all returned elements to the given interface.
4021 * The function recurses inside child bins. The iterator will yield a series
4022 * of #GstElement that should be unreffed after use.
4024 * Each element yielded by the iterator will have its refcount increased, so
4027 * MT safe. Caller owns returned value.
4029 * Returns: (transfer full): a #GstIterator of #GstElement for all elements
4030 * in the bin implementing the given interface, or NULL
4033 gst_bin_iterate_all_by_interface (GstBin * bin, GType iface)
4035 GstIterator *children;
4036 GstIterator *result;
4037 GValue viface = { 0, };
4039 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
4040 g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
4042 g_value_init (&viface, G_TYPE_POINTER);
4043 g_value_set_pointer (&viface, (gpointer) iface);
4045 children = gst_bin_iterate_recurse (bin);
4046 result = gst_iterator_filter (children, (GCompareFunc) compare_interface,
4049 g_value_unset (&viface);