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., 51 Franklin St, Fifth Floor,
21 * Boston, MA 02110-1301, 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_CHANGED</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.
376 g_object_class_install_property (gobject_class, PROP_ASYNC_HANDLING,
377 g_param_spec_boolean ("async-handling", "Async Handling",
378 "The bin will handle Asynchronous state changes",
379 DEFAULT_ASYNC_HANDLING, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
382 * GstBin::element-added:
384 * @element: the #GstElement that was added to the bin
386 * Will be emitted after the element was added to the bin.
388 gst_bin_signals[ELEMENT_ADDED] =
389 g_signal_new ("element-added", G_TYPE_FROM_CLASS (klass),
390 G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_added), NULL,
391 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
393 * GstBin::element-removed:
395 * @element: the #GstElement that was removed from the bin
397 * Will be emitted after the element was removed from the bin.
399 gst_bin_signals[ELEMENT_REMOVED] =
400 g_signal_new ("element-removed", G_TYPE_FROM_CLASS (klass),
401 G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_removed), NULL,
402 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
404 * GstBin::do-latency:
407 * Will be emitted when the bin needs to perform latency calculations. This
408 * signal is only emited for toplevel bins or when async-handling is
411 * Only one signal handler is invoked. If no signals are connected, the
412 * default handler is invoked, which will query and distribute the lowest
413 * possible latency to all sinks.
415 * Connect to this signal if the default latency calculations are not
416 * sufficient, like when you need different latencies for different sinks in
419 gst_bin_signals[DO_LATENCY] =
420 g_signal_new ("do-latency", G_TYPE_FROM_CLASS (klass),
421 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstBinClass, do_latency),
422 _gst_boolean_accumulator, NULL, g_cclosure_marshal_generic,
423 G_TYPE_BOOLEAN, 0, G_TYPE_NONE);
426 * GstBin:message-forward:
428 * Forward all children messages, even those that would normally be filtered by
429 * the bin. This can be interesting when one wants to be notified of the EOS
430 * state of individual elements, for example.
432 * The messages are converted to an ELEMENT message with the bin as the
433 * source. The structure of the message is named 'GstBinForwarded' and contains
434 * a field named 'message' of type GST_TYPE_MESSAGE that contains the original
437 g_object_class_install_property (gobject_class, PROP_MESSAGE_FORWARD,
438 g_param_spec_boolean ("message-forward", "Message Forward",
439 "Forwards all children messages",
440 DEFAULT_MESSAGE_FORWARD, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
442 gobject_class->dispose = gst_bin_dispose;
444 gst_element_class_set_static_metadata (gstelement_class, "Generic bin",
446 "Simple container object",
447 "Erik Walthinsen <omega@cse.ogi.edu>,"
448 "Wim Taymans <wim.taymans@gmail.com>");
450 gstelement_class->change_state =
451 GST_DEBUG_FUNCPTR (gst_bin_change_state_func);
452 gstelement_class->state_changed = GST_DEBUG_FUNCPTR (gst_bin_state_changed);
453 gstelement_class->get_state = GST_DEBUG_FUNCPTR (gst_bin_get_state_func);
455 gstelement_class->get_index = GST_DEBUG_FUNCPTR (gst_bin_get_index_func);
456 gstelement_class->set_index = GST_DEBUG_FUNCPTR (gst_bin_set_index_func);
458 gstelement_class->provide_clock =
459 GST_DEBUG_FUNCPTR (gst_bin_provide_clock_func);
460 gstelement_class->set_clock = GST_DEBUG_FUNCPTR (gst_bin_set_clock_func);
462 gstelement_class->send_event = GST_DEBUG_FUNCPTR (gst_bin_send_event);
463 gstelement_class->query = GST_DEBUG_FUNCPTR (gst_bin_query);
465 klass->add_element = GST_DEBUG_FUNCPTR (gst_bin_add_func);
466 klass->remove_element = GST_DEBUG_FUNCPTR (gst_bin_remove_func);
467 klass->handle_message = GST_DEBUG_FUNCPTR (gst_bin_handle_message_func);
469 klass->do_latency = GST_DEBUG_FUNCPTR (gst_bin_do_latency_func);
471 GST_DEBUG ("creating bin thread pool");
474 g_thread_pool_new ((GFunc) gst_bin_continue_func, NULL, -1, FALSE, &err);
476 g_critical ("could alloc threadpool %s", err->message);
481 gst_bin_init (GstBin * bin)
485 bin->numchildren = 0;
486 bin->children = NULL;
487 bin->children_cookie = 0;
488 bin->messages = NULL;
489 bin->provided_clock = NULL;
490 bin->clock_dirty = FALSE;
492 /* Set up a bus for listening to child elements */
493 bus = g_object_new (GST_TYPE_BUS, "enable-async", FALSE, NULL);
494 bin->child_bus = bus;
495 GST_DEBUG_OBJECT (bin, "using bus %" GST_PTR_FORMAT " to listen to children",
497 gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bin_bus_handler, bin,
500 bin->priv = GST_BIN_GET_PRIVATE (bin);
501 bin->priv->asynchandling = DEFAULT_ASYNC_HANDLING;
502 bin->priv->structure_cookie = 0;
503 bin->priv->message_forward = DEFAULT_MESSAGE_FORWARD;
507 gst_bin_dispose (GObject * object)
509 GstBin *bin = GST_BIN_CAST (object);
510 GstBus **child_bus_p = &bin->child_bus;
511 GstClock **provided_clock_p = &bin->provided_clock;
512 GstElement **clock_provider_p = &bin->clock_provider;
514 GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
516 GST_OBJECT_LOCK (object);
517 gst_object_replace ((GstObject **) child_bus_p, NULL);
518 gst_object_replace ((GstObject **) provided_clock_p, NULL);
519 gst_object_replace ((GstObject **) clock_provider_p, NULL);
520 bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
521 GST_OBJECT_UNLOCK (object);
523 while (bin->children) {
524 gst_bin_remove (bin, GST_ELEMENT_CAST (bin->children->data));
526 if (G_UNLIKELY (bin->children != NULL)) {
527 g_critical ("could not remove elements from bin '%s'",
528 GST_STR_NULL (GST_OBJECT_NAME (object)));
531 G_OBJECT_CLASS (parent_class)->dispose (object);
536 * @name: the name of the new bin
538 * Creates a new bin with the given name.
540 * Returns: (transfer floating): a new #GstBin
543 gst_bin_new (const gchar * name)
545 return gst_element_factory_make ("bin", name);
549 gst_bin_set_property (GObject * object, guint prop_id,
550 const GValue * value, GParamSpec * pspec)
554 gstbin = GST_BIN_CAST (object);
557 case PROP_ASYNC_HANDLING:
558 GST_OBJECT_LOCK (gstbin);
559 gstbin->priv->asynchandling = g_value_get_boolean (value);
560 GST_OBJECT_UNLOCK (gstbin);
562 case PROP_MESSAGE_FORWARD:
563 GST_OBJECT_LOCK (gstbin);
564 gstbin->priv->message_forward = g_value_get_boolean (value);
565 GST_OBJECT_UNLOCK (gstbin);
568 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
574 gst_bin_get_property (GObject * object, guint prop_id,
575 GValue * value, GParamSpec * pspec)
579 gstbin = GST_BIN_CAST (object);
582 case PROP_ASYNC_HANDLING:
583 GST_OBJECT_LOCK (gstbin);
584 g_value_set_boolean (value, gstbin->priv->asynchandling);
585 GST_OBJECT_UNLOCK (gstbin);
587 case PROP_MESSAGE_FORWARD:
588 GST_OBJECT_LOCK (gstbin);
589 g_value_set_boolean (value, gstbin->priv->message_forward);
590 GST_OBJECT_UNLOCK (gstbin);
593 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
599 /* return the cached index */
601 gst_bin_get_index_func (GstElement * element)
606 bin = GST_BIN_CAST (element);
608 GST_OBJECT_LOCK (bin);
609 if ((result = bin->priv->index))
610 gst_object_ref (result);
611 GST_OBJECT_UNLOCK (bin);
616 /* set the index on all elements in this bin
621 gst_bin_set_index_func (GstElement * element, GstIndex * index)
627 GValue data = { 0, };
629 bin = GST_BIN_CAST (element);
631 GST_OBJECT_LOCK (bin);
632 old = bin->priv->index;
633 if (G_UNLIKELY (old == index))
636 gst_object_ref (index);
637 bin->priv->index = index;
638 GST_OBJECT_UNLOCK (bin);
641 gst_object_unref (old);
643 it = gst_bin_iterate_elements (bin);
645 /* set the index on all elements in the bin */
648 switch (gst_iterator_next (it, &data)) {
649 case GST_ITERATOR_OK:
651 GstElement *child = g_value_get_object (&data);
653 GST_DEBUG_OBJECT (bin, "setting index on '%s'",
654 GST_ELEMENT_NAME (child));
655 gst_element_set_index (child, index);
657 g_value_reset (&data);
660 case GST_ITERATOR_RESYNC:
661 GST_DEBUG_OBJECT (bin, "iterator doing resync");
662 gst_iterator_resync (it);
665 case GST_ITERATOR_DONE:
666 GST_DEBUG_OBJECT (bin, "iterator done");
671 g_value_unset (&data);
672 gst_iterator_free (it);
677 GST_DEBUG_OBJECT (bin, "index was already set");
678 GST_OBJECT_UNLOCK (bin);
684 /* set the clock on all elements in this bin
689 gst_bin_set_clock_func (GstElement * element, GstClock * clock)
695 GValue data = { 0, };
697 bin = GST_BIN_CAST (element);
699 it = gst_bin_iterate_elements (bin);
703 switch (gst_iterator_next (it, &data)) {
704 case GST_ITERATOR_OK:
706 GstElement *child = g_value_get_object (&data);
708 res &= gst_element_set_clock (child, clock);
710 g_value_reset (&data);
713 case GST_ITERATOR_RESYNC:
714 GST_DEBUG_OBJECT (bin, "iterator doing resync");
715 gst_iterator_resync (it);
719 case GST_ITERATOR_DONE:
720 GST_DEBUG_OBJECT (bin, "iterator done");
725 g_value_unset (&data);
726 gst_iterator_free (it);
729 res = GST_ELEMENT_CLASS (parent_class)->set_clock (element, clock);
734 /* get the clock for this bin by asking all of the children in this bin
736 * The ref of the returned clock in increased so unref after usage.
738 * We loop the elements in state order and pick the last clock we can
739 * get. This makes sure we get a clock from the source.
744 gst_bin_provide_clock_func (GstElement * element)
746 GstClock *result = NULL;
747 GstElement *provider = NULL;
752 GstClock **provided_clock_p;
753 GstElement **clock_provider_p;
755 bin = GST_BIN_CAST (element);
757 GST_OBJECT_LOCK (bin);
758 if (!bin->clock_dirty)
761 GST_DEBUG_OBJECT (bin, "finding new clock");
763 it = gst_bin_sort_iterator_new (bin);
764 GST_OBJECT_UNLOCK (bin);
768 switch (gst_iterator_next (it, &val)) {
769 case GST_ITERATOR_OK:
771 GstElement *child = g_value_get_object (&val);
774 clock = gst_element_provide_clock (child);
776 GST_DEBUG_OBJECT (bin, "found candidate clock %p by element %s",
777 clock, GST_ELEMENT_NAME (child));
779 gst_object_unref (result);
780 gst_object_unref (provider);
783 provider = gst_object_ref (child);
786 g_value_reset (&val);
789 case GST_ITERATOR_RESYNC:
790 gst_iterator_resync (it);
793 case GST_ITERATOR_DONE:
798 g_value_unset (&val);
799 gst_iterator_free (it);
801 GST_OBJECT_LOCK (bin);
802 if (!bin->clock_dirty) {
804 gst_object_unref (provider);
806 gst_object_unref (result);
812 provided_clock_p = &bin->provided_clock;
813 clock_provider_p = &bin->clock_provider;
814 gst_object_replace ((GstObject **) provided_clock_p, (GstObject *) result);
815 gst_object_replace ((GstObject **) clock_provider_p, (GstObject *) provider);
816 bin->clock_dirty = FALSE;
817 GST_DEBUG_OBJECT (bin,
818 "provided new clock %" GST_PTR_FORMAT " by provider %" GST_PTR_FORMAT,
820 /* Provider is not being returned to caller, just the result */
822 gst_object_unref (provider);
823 GST_OBJECT_UNLOCK (bin);
829 if ((result = bin->provided_clock))
830 gst_object_ref (result);
831 GST_DEBUG_OBJECT (bin, "returning old clock %p", result);
832 GST_OBJECT_UNLOCK (bin);
839 * functions for manipulating cached messages
844 GstMessageType types;
847 /* check if a message is of given src and type */
849 message_check (GstMessage * message, MessageFind * target)
854 eq &= GST_MESSAGE_SRC (message) == target->src;
856 eq &= (GST_MESSAGE_TYPE (message) & target->types) != 0;
857 GST_LOG ("looking at message %p: %d", message, eq);
863 find_message (GstBin * bin, GstObject * src, GstMessageType types)
871 result = g_list_find_custom (bin->messages, &find,
872 (GCompareFunc) message_check);
875 GST_DEBUG_OBJECT (bin, "we found a message %p from %s matching types %08x",
876 result->data, GST_OBJECT_NAME (GST_MESSAGE_CAST (result->data)->src),
879 GST_DEBUG_OBJECT (bin, "no message found matching types %08x", types);
880 #ifndef GST_DISABLE_GST_DEBUG
884 for (i = 0; i < 32; i++)
885 if (types & (1 << i))
886 GST_DEBUG_OBJECT (bin, " %s", gst_message_type_get_name (1 << i));
894 /* with LOCK, returns TRUE if message had a valid SRC, takes ownership of
897 * A message that is cached and has the same SRC and type is replaced
898 * by the given message.
901 bin_replace_message (GstBin * bin, GstMessage * message, GstMessageType types)
907 if ((src = GST_MESSAGE_SRC (message))) {
908 /* first find the previous message posted by this element */
909 if ((previous = find_message (bin, src, types))) {
910 GstMessage *previous_msg;
912 /* if we found a previous message, replace it */
913 previous_msg = previous->data;
914 previous->data = message;
916 GST_DEBUG_OBJECT (bin, "replace old message %s from %s with %s message",
917 GST_MESSAGE_TYPE_NAME (previous_msg), GST_ELEMENT_NAME (src),
918 GST_MESSAGE_TYPE_NAME (message));
920 gst_message_unref (previous_msg);
922 /* keep new message */
923 bin->messages = g_list_prepend (bin->messages, message);
925 GST_DEBUG_OBJECT (bin, "got new message %p, %s from %s",
926 message, GST_MESSAGE_TYPE_NAME (message), GST_ELEMENT_NAME (src));
929 GST_DEBUG_OBJECT (bin, "got message %s from (NULL), not processing",
930 GST_MESSAGE_TYPE_NAME (message));
932 gst_message_unref (message);
937 /* with LOCK. Remove all messages of given types */
939 bin_remove_messages (GstBin * bin, GstObject * src, GstMessageType types)
947 for (walk = bin->messages; walk; walk = next) {
948 GstMessage *message = (GstMessage *) walk->data;
950 next = g_list_next (walk);
952 if (message_check (message, &find) == 0) {
953 GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
954 "deleting message %p of types 0x%08x", message, types);
955 bin->messages = g_list_delete_link (bin->messages, walk);
956 gst_message_unref (message);
958 GST_DEBUG_OBJECT (GST_MESSAGE_SRC (message),
959 "not deleting message %p of type 0x%08x", message,
960 GST_MESSAGE_TYPE (message));
966 /* Check if the bin is EOS. We do this by scanning all sinks and
967 * checking if they posted an EOS message.
969 * call with bin LOCK */
971 is_eos (GstBin * bin, guint32 * seqnum)
978 for (walk = bin->children; walk; walk = g_list_next (walk)) {
981 element = GST_ELEMENT_CAST (walk->data);
982 if (bin_element_is_sink (element, bin) == 0) {
983 /* check if element posted EOS */
985 find_message (bin, GST_OBJECT_CAST (element), GST_MESSAGE_EOS))) {
986 GST_DEBUG ("sink '%s' posted EOS", GST_ELEMENT_NAME (element));
987 *seqnum = gst_message_get_seqnum (GST_MESSAGE_CAST (msgs->data));
990 GST_DEBUG ("sink '%s' did not post EOS yet",
991 GST_ELEMENT_NAME (element));
997 /* FIXME: Some tests (e.g. elements/capsfilter) use
998 * pipelines with a dangling sinkpad but no sink element.
999 * These tests assume that no EOS message is ever
1000 * posted on the bus so let's keep that behaviour.
1001 * In valid pipelines this doesn't make a difference.
1003 return result && n_eos > 0;
1007 /* Check if the bin is STREAM_START. We do this by scanning all sinks and
1008 * checking if they posted an STREAM_START message.
1010 * call with bin LOCK */
1012 is_stream_start (GstBin * bin, guint32 * seqnum)
1015 gint n_stream_start = 0;
1019 for (walk = bin->children; walk; walk = g_list_next (walk)) {
1020 GstElement *element;
1022 element = GST_ELEMENT_CAST (walk->data);
1023 if (bin_element_is_sink (element, bin) == 0) {
1024 /* check if element posted STREAM_START */
1026 find_message (bin, GST_OBJECT_CAST (element),
1027 GST_MESSAGE_STREAM_START))) {
1028 GST_DEBUG ("sink '%s' posted STREAM_START", GST_ELEMENT_NAME (element));
1029 *seqnum = gst_message_get_seqnum (GST_MESSAGE_CAST (msgs->data));
1032 GST_DEBUG ("sink '%s' did not post STREAM_START yet",
1033 GST_ELEMENT_NAME (element));
1044 unlink_pads (const GValue * item, gpointer user_data)
1049 pad = g_value_get_object (item);
1051 if ((peer = gst_pad_get_peer (pad))) {
1052 if (gst_pad_get_direction (pad) == GST_PAD_SRC)
1053 gst_pad_unlink (pad, peer);
1055 gst_pad_unlink (peer, pad);
1056 gst_object_unref (peer);
1060 /* vmethod that adds an element to a bin
1065 gst_bin_add_func (GstBin * bin, GstElement * element)
1069 gboolean is_sink, is_source, provides_clock, requires_clock;
1070 GstMessage *clock_message = NULL, *async_message = NULL;
1071 GstStateChangeReturn ret;
1073 GST_DEBUG_OBJECT (bin, "element :%s", GST_ELEMENT_NAME (element));
1075 /* we obviously can't add ourself to ourself */
1076 if (G_UNLIKELY (GST_ELEMENT_CAST (element) == GST_ELEMENT_CAST (bin)))
1079 /* get the element name to make sure it is unique in this bin. */
1080 GST_OBJECT_LOCK (element);
1081 elem_name = g_strdup (GST_ELEMENT_NAME (element));
1082 is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SINK);
1083 is_source = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SOURCE);
1085 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1087 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1088 GST_OBJECT_UNLOCK (element);
1090 GST_OBJECT_LOCK (bin);
1092 /* then check to see if the element's name is already taken in the bin,
1093 * we can safely take the lock here. This check is probably bogus because
1094 * you can safely change the element name after this check and before setting
1095 * the object parent. The window is very small though... */
1096 if (G_UNLIKELY (!gst_object_check_uniqueness (bin->children, elem_name)))
1097 goto duplicate_name;
1099 /* set the element's parent and add the element to the bin's list of children */
1100 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (element),
1101 GST_OBJECT_CAST (bin))))
1104 /* if we add a sink we become a sink */
1106 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was sink",
1108 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_SINK);
1111 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was source",
1113 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_SOURCE);
1115 if (provides_clock) {
1116 GST_DEBUG_OBJECT (bin, "element \"%s\" can provide a clock", elem_name);
1118 gst_message_new_clock_provide (GST_OBJECT_CAST (element), NULL, TRUE);
1119 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1121 if (requires_clock) {
1122 GST_DEBUG_OBJECT (bin, "element \"%s\" requires a clock", elem_name);
1123 GST_OBJECT_FLAG_SET (bin, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1126 bin->children = g_list_prepend (bin->children, element);
1128 bin->children_cookie++;
1129 bin->priv->structure_cookie++;
1131 /* distribute the bus */
1132 gst_element_set_bus (element, bin->child_bus);
1134 /* propagate the current base_time, start_time and clock */
1135 gst_element_set_base_time (element, GST_ELEMENT_CAST (bin)->base_time);
1136 gst_element_set_start_time (element, GST_ELEMENT_START_TIME (bin));
1137 /* it's possible that the element did not accept the clock but
1138 * that is not important right now. When the pipeline goes to PLAYING,
1139 * a new clock will be selected */
1140 gst_element_set_clock (element, GST_ELEMENT_CLOCK (bin));
1143 /* set the cached index on the children */
1144 if (bin->priv->index)
1145 gst_element_set_index (element, bin->priv->index);
1148 ret = GST_STATE_RETURN (bin);
1149 /* no need to update the state if we are in error */
1150 if (ret == GST_STATE_CHANGE_FAILURE)
1151 goto no_state_recalc;
1153 /* update the bin state, the new element could have been an ASYNC or
1154 * NO_PREROLL element */
1155 ret = GST_STATE_RETURN (element);
1156 GST_DEBUG_OBJECT (bin, "added %s element",
1157 gst_element_state_change_return_get_name (ret));
1160 case GST_STATE_CHANGE_ASYNC:
1162 /* create message to track this aync element when it posts an async-done
1164 async_message = gst_message_new_async_start (GST_OBJECT_CAST (element));
1167 case GST_STATE_CHANGE_NO_PREROLL:
1168 /* ignore all async elements we might have and commit our state */
1169 bin_handle_async_done (bin, ret, FALSE, GST_CLOCK_TIME_NONE);
1171 case GST_STATE_CHANGE_FAILURE:
1178 GST_OBJECT_UNLOCK (bin);
1180 /* post the messages on the bus of the element so that the bin can handle
1183 gst_element_post_message (GST_ELEMENT_CAST (element), clock_message);
1186 gst_element_post_message (GST_ELEMENT_CAST (element), async_message);
1188 /* unlink all linked pads */
1189 it = gst_element_iterate_pads (element);
1190 gst_iterator_foreach (it, (GstIteratorForeachFunction) unlink_pads, NULL);
1191 gst_iterator_free (it);
1193 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "added element \"%s\"",
1196 g_signal_emit (bin, gst_bin_signals[ELEMENT_ADDED], 0, element);
1197 gst_child_proxy_child_added ((GstChildProxy *) bin, (GObject *) element,
1204 /* ERROR handling here */
1207 GST_OBJECT_LOCK (bin);
1208 g_warning ("Cannot add bin '%s' to itself", GST_ELEMENT_NAME (bin));
1209 GST_OBJECT_UNLOCK (bin);
1214 g_warning ("Name '%s' is not unique in bin '%s', not adding",
1215 elem_name, GST_ELEMENT_NAME (bin));
1216 GST_OBJECT_UNLOCK (bin);
1222 g_warning ("Element '%s' already has parent", elem_name);
1223 GST_OBJECT_UNLOCK (bin);
1232 * @element: (transfer full): the #GstElement to add
1234 * Adds the given element to the bin. Sets the element's parent, and thus
1235 * takes ownership of the element. An element can only be added to one bin.
1237 * If the element's pads are linked to other pads, the pads will be unlinked
1238 * before the element is added to the bin.
1241 * When you add an element to an already-running pipeline, you will have to
1242 * take care to set the state of the newly-added element to the desired
1243 * state (usually PLAYING or PAUSED, same you set the pipeline to originally)
1244 * with gst_element_set_state(), or use gst_element_sync_state_with_parent().
1245 * The bin or pipeline will not take care of this for you.
1250 * Returns: TRUE if the element could be added, FALSE if
1251 * the bin does not want to accept the element.
1254 gst_bin_add (GstBin * bin, GstElement * element)
1256 GstBinClass *bclass;
1259 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
1260 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1262 bclass = GST_BIN_GET_CLASS (bin);
1264 if (G_UNLIKELY (bclass->add_element == NULL))
1267 GST_CAT_DEBUG (GST_CAT_PARENTAGE, "adding element %s to bin %s",
1268 GST_STR_NULL (GST_ELEMENT_NAME (element)),
1269 GST_STR_NULL (GST_ELEMENT_NAME (bin)));
1271 result = bclass->add_element (bin, element);
1275 /* ERROR handling */
1278 g_warning ("adding elements to bin '%s' is not supported",
1279 GST_ELEMENT_NAME (bin));
1284 /* remove an element from the bin
1289 gst_bin_remove_func (GstBin * bin, GstElement * element)
1293 gboolean is_sink, is_source, provides_clock, requires_clock;
1294 gboolean othersink, othersource, otherprovider, otherrequirer, found;
1295 GstMessage *clock_message = NULL;
1296 GstClock **provided_clock_p;
1297 GstElement **clock_provider_p;
1299 gboolean other_async, this_async, have_no_preroll;
1300 GstStateChangeReturn ret;
1302 GST_DEBUG_OBJECT (bin, "element :%s", GST_ELEMENT_NAME (element));
1304 GST_OBJECT_LOCK (bin);
1306 GST_OBJECT_LOCK (element);
1307 elem_name = g_strdup (GST_ELEMENT_NAME (element));
1309 if (GST_OBJECT_PARENT (element) != GST_OBJECT_CAST (bin))
1312 /* remove the parent ref */
1313 GST_OBJECT_PARENT (element) = NULL;
1315 /* grab element name so we can print it */
1316 is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SINK);
1317 is_source = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SOURCE);
1319 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1321 GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1322 GST_OBJECT_UNLOCK (element);
1326 othersource = FALSE;
1327 otherprovider = FALSE;
1328 otherrequirer = FALSE;
1329 have_no_preroll = FALSE;
1330 /* iterate the elements, we collect which ones are async and no_preroll. We
1331 * also remove the element when we find it. */
1332 for (walk = bin->children; walk; walk = next) {
1333 GstElement *child = GST_ELEMENT_CAST (walk->data);
1335 next = g_list_next (walk);
1337 if (child == element) {
1339 /* remove the element */
1340 bin->children = g_list_delete_link (bin->children, walk);
1342 gboolean child_sink, child_source, child_provider, child_requirer;
1344 GST_OBJECT_LOCK (child);
1345 child_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SINK);
1346 child_source = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SOURCE);
1348 GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1350 GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1351 /* when we remove a sink, check if there are other sinks. */
1352 if (is_sink && !othersink && child_sink)
1354 if (is_source && !othersource && child_source)
1356 if (provides_clock && !otherprovider && child_provider)
1357 otherprovider = TRUE;
1358 if (requires_clock && !otherrequirer && child_requirer)
1359 otherrequirer = TRUE;
1360 /* check if we have NO_PREROLL children */
1361 if (GST_STATE_RETURN (child) == GST_STATE_CHANGE_NO_PREROLL)
1362 have_no_preroll = TRUE;
1363 GST_OBJECT_UNLOCK (child);
1367 /* the element must have been in the bin's list of children */
1368 if (G_UNLIKELY (!found))
1371 /* we now removed the element from the list of elements, increment the cookie
1372 * so that others can detect a change in the children list. */
1374 bin->children_cookie++;
1375 bin->priv->structure_cookie++;
1377 if (is_sink && !othersink) {
1378 /* we're not a sink anymore */
1379 GST_DEBUG_OBJECT (bin, "we removed the last sink");
1380 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_SINK);
1382 if (is_source && !othersource) {
1383 /* we're not a source anymore */
1384 GST_DEBUG_OBJECT (bin, "we removed the last source");
1385 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_SOURCE);
1387 if (provides_clock && !otherprovider) {
1388 /* we're not a clock provider anymore */
1389 GST_DEBUG_OBJECT (bin, "we removed the last clock provider");
1390 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_PROVIDE_CLOCK);
1392 if (requires_clock && !otherrequirer) {
1393 /* we're not a clock requirer anymore */
1394 GST_DEBUG_OBJECT (bin, "we removed the last clock requirer");
1395 GST_OBJECT_FLAG_UNSET (bin, GST_ELEMENT_FLAG_REQUIRE_CLOCK);
1398 /* if the clock provider for this element is removed, we lost
1399 * the clock as well, we need to inform the parent of this
1400 * so that it can select a new clock */
1401 if (bin->clock_provider == element) {
1402 GST_DEBUG_OBJECT (bin, "element \"%s\" provided the clock", elem_name);
1403 bin->clock_dirty = TRUE;
1405 gst_message_new_clock_lost (GST_OBJECT_CAST (bin), bin->provided_clock);
1406 provided_clock_p = &bin->provided_clock;
1407 clock_provider_p = &bin->clock_provider;
1408 gst_object_replace ((GstObject **) provided_clock_p, NULL);
1409 gst_object_replace ((GstObject **) clock_provider_p, NULL);
1412 /* remove messages for the element, if there was a pending ASYNC_START
1413 * message we must see if removing the element caused the bin to lose its
1416 other_async = FALSE;
1417 for (walk = bin->messages; walk; walk = next) {
1418 GstMessage *message = (GstMessage *) walk->data;
1419 GstElement *src = GST_ELEMENT_CAST (GST_MESSAGE_SRC (message));
1422 next = g_list_next (walk);
1425 switch (GST_MESSAGE_TYPE (message)) {
1426 case GST_MESSAGE_ASYNC_START:
1432 GST_DEBUG_OBJECT (src, "looking at message %p", message);
1434 case GST_MESSAGE_STRUCTURE_CHANGE:
1438 GST_DEBUG_OBJECT (src, "looking at structure change message %p",
1440 /* it's unlikely that this message is still in the list of messages
1441 * because this would mean that a link/unlink is busy in another thread
1442 * while we remove the element. We still have to remove the message
1443 * because we might not receive the done message anymore when the element
1444 * is removed from the bin. */
1445 gst_message_parse_structure_change (message, NULL, &owner, NULL);
1446 if (owner == element)
1457 /* delete all message types */
1458 GST_DEBUG_OBJECT (src, "deleting message %p of element \"%s\"",
1459 message, elem_name);
1460 bin->messages = g_list_delete_link (bin->messages, walk);
1461 gst_message_unref (message);
1465 /* get last return */
1466 ret = GST_STATE_RETURN (bin);
1468 /* no need to update the state if we are in error */
1469 if (ret == GST_STATE_CHANGE_FAILURE)
1470 goto no_state_recalc;
1472 if (!other_async && this_async) {
1473 /* all other elements were not async and we removed the async one,
1474 * handle the async-done case because we are not async anymore now. */
1475 GST_DEBUG_OBJECT (bin,
1476 "we removed the last async element, have no_preroll %d",
1479 /* the current state return of the bin depends on if there are no_preroll
1480 * elements in the pipeline or not */
1481 if (have_no_preroll)
1482 ret = GST_STATE_CHANGE_NO_PREROLL;
1484 ret = GST_STATE_CHANGE_SUCCESS;
1486 bin_handle_async_done (bin, ret, FALSE, GST_CLOCK_TIME_NONE);
1488 GST_DEBUG_OBJECT (bin,
1489 "recalc state preroll: %d, other async: %d, this async %d",
1490 have_no_preroll, other_async, this_async);
1492 if (have_no_preroll) {
1493 ret = GST_STATE_CHANGE_NO_PREROLL;
1494 } else if (other_async) {
1495 /* there are other async elements and we were not doing an async state
1496 * change, change our pending state and go async */
1497 if (GST_STATE_PENDING (bin) == GST_STATE_VOID_PENDING) {
1498 GST_STATE_NEXT (bin) = GST_STATE (bin);
1499 GST_STATE_PENDING (bin) = GST_STATE (bin);
1501 ret = GST_STATE_CHANGE_ASYNC;
1503 GST_STATE_RETURN (bin) = ret;
1507 gst_element_set_bus (element, NULL);
1508 /* Clear the clock we provided to the element */
1509 gst_element_set_clock (element, NULL);
1510 GST_OBJECT_UNLOCK (bin);
1513 gst_element_post_message (GST_ELEMENT_CAST (bin), clock_message);
1515 /* unlink all linked pads */
1516 it = gst_element_iterate_pads (element);
1517 gst_iterator_foreach (it, (GstIteratorForeachFunction) unlink_pads, NULL);
1518 gst_iterator_free (it);
1520 GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
1523 g_signal_emit (bin, gst_bin_signals[ELEMENT_REMOVED], 0, element);
1524 gst_child_proxy_child_removed ((GstChildProxy *) bin, (GObject *) element,
1528 /* element is really out of our control now */
1529 gst_object_unref (element);
1533 /* ERROR handling */
1536 g_warning ("Element '%s' is not in bin '%s'", elem_name,
1537 GST_ELEMENT_NAME (bin));
1538 GST_OBJECT_UNLOCK (element);
1539 GST_OBJECT_UNLOCK (bin);
1548 * @element: (transfer none): the #GstElement to remove
1550 * Removes the element from the bin, unparenting it as well.
1551 * Unparenting the element means that the element will be dereferenced,
1552 * so if the bin holds the only reference to the element, the element
1553 * will be freed in the process of removing it from the bin. If you
1554 * want the element to still exist after removing, you need to call
1555 * gst_object_ref() before removing it from the bin.
1557 * If the element's pads are linked to other pads, the pads will be unlinked
1558 * before the element is removed from the bin.
1562 * Returns: TRUE if the element could be removed, FALSE if
1563 * the bin does not want to remove the element.
1566 gst_bin_remove (GstBin * bin, GstElement * element)
1568 GstBinClass *bclass;
1571 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
1572 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1574 bclass = GST_BIN_GET_CLASS (bin);
1576 if (G_UNLIKELY (bclass->remove_element == NULL))
1579 GST_CAT_DEBUG (GST_CAT_PARENTAGE, "removing element %s from bin %s",
1580 GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
1582 result = bclass->remove_element (bin, element);
1586 /* ERROR handling */
1589 g_warning ("removing elements from bin '%s' is not supported",
1590 GST_ELEMENT_NAME (bin));
1596 * gst_bin_iterate_elements:
1599 * Gets an iterator for the elements in this bin.
1601 * Each element yielded by the iterator will have its refcount increased, so
1604 * MT safe. Caller owns returned value.
1606 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1609 gst_bin_iterate_elements (GstBin * bin)
1611 GstIterator *result;
1613 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1615 GST_OBJECT_LOCK (bin);
1616 result = gst_iterator_new_list (GST_TYPE_ELEMENT,
1617 GST_OBJECT_GET_LOCK (bin),
1618 &bin->children_cookie, &bin->children, (GObject *) bin, NULL);
1619 GST_OBJECT_UNLOCK (bin);
1624 static GstIteratorItem
1625 iterate_child_recurse (GstIterator * it, const GValue * item)
1627 GstElement *child = g_value_get_object (item);
1629 if (GST_IS_BIN (child)) {
1630 GstIterator *other = gst_bin_iterate_recurse (GST_BIN_CAST (child));
1632 gst_iterator_push (it, other);
1634 return GST_ITERATOR_ITEM_PASS;
1638 * gst_bin_iterate_recurse:
1641 * Gets an iterator for the elements in this bin.
1642 * This iterator recurses into GstBin children.
1644 * Each element yielded by the iterator will have its refcount increased, so
1647 * MT safe. Caller owns returned value.
1649 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1652 gst_bin_iterate_recurse (GstBin * bin)
1654 GstIterator *result;
1656 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1658 GST_OBJECT_LOCK (bin);
1659 result = gst_iterator_new_list (GST_TYPE_ELEMENT,
1660 GST_OBJECT_GET_LOCK (bin),
1661 &bin->children_cookie,
1663 (GObject *) bin, (GstIteratorItemFunction) iterate_child_recurse);
1664 GST_OBJECT_UNLOCK (bin);
1669 /* returns 0 when TRUE because this is a GCompareFunc */
1672 bin_element_is_sink (GstElement * child, GstBin * bin)
1676 /* we lock the child here for the remainder of the function to
1677 * get its name and flag safely. */
1678 GST_OBJECT_LOCK (child);
1679 is_sink = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SINK);
1681 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
1682 "child %s %s sink", GST_OBJECT_NAME (child), is_sink ? "is" : "is not");
1684 GST_OBJECT_UNLOCK (child);
1685 return is_sink ? 0 : 1;
1689 sink_iterator_filter (const GValue * vchild, GValue * vbin)
1691 GstBin *bin = g_value_get_object (vbin);
1692 GstElement *child = g_value_get_object (vchild);
1694 return (bin_element_is_sink (child, bin));
1698 * gst_bin_iterate_sinks:
1701 * Gets an iterator for all elements in the bin that have the
1702 * #GST_ELEMENT_FLAG_SINK flag set.
1704 * Each element yielded by the iterator will have its refcount increased, so
1707 * MT safe. Caller owns returned value.
1709 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1712 gst_bin_iterate_sinks (GstBin * bin)
1714 GstIterator *children;
1715 GstIterator *result;
1716 GValue vbin = { 0, };
1718 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1720 g_value_init (&vbin, GST_TYPE_BIN);
1721 g_value_set_object (&vbin, bin);
1723 children = gst_bin_iterate_elements (bin);
1724 result = gst_iterator_filter (children,
1725 (GCompareFunc) sink_iterator_filter, &vbin);
1727 g_value_unset (&vbin);
1732 /* returns 0 when TRUE because this is a GCompareFunc */
1735 bin_element_is_src (GstElement * child, GstBin * bin)
1739 /* we lock the child here for the remainder of the function to
1740 * get its name and other info safely. */
1741 GST_OBJECT_LOCK (child);
1742 is_src = GST_OBJECT_FLAG_IS_SET (child, GST_ELEMENT_FLAG_SOURCE);
1744 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
1745 "child %s %s src", GST_OBJECT_NAME (child), is_src ? "is" : "is not");
1747 GST_OBJECT_UNLOCK (child);
1748 return is_src ? 0 : 1;
1752 src_iterator_filter (const GValue * vchild, GValue * vbin)
1754 GstBin *bin = g_value_get_object (vbin);
1755 GstElement *child = g_value_get_object (vchild);
1757 return (bin_element_is_src (child, bin));
1761 * gst_bin_iterate_sources:
1764 * Gets an iterator for all elements in the bin that have the
1765 * #GST_ELEMENT_FLAG_SOURCE flag set.
1767 * Each element yielded by the iterator will have its refcount increased, so
1770 * MT safe. Caller owns returned value.
1772 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
1775 gst_bin_iterate_sources (GstBin * bin)
1777 GstIterator *children;
1778 GstIterator *result;
1779 GValue vbin = { 0, };
1781 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1783 g_value_init (&vbin, GST_TYPE_BIN);
1784 g_value_set_object (&vbin, bin);
1786 children = gst_bin_iterate_elements (bin);
1787 result = gst_iterator_filter (children,
1788 (GCompareFunc) src_iterator_filter, &vbin);
1790 g_value_unset (&vbin);
1798 static GstStateChangeReturn
1799 gst_bin_get_state_func (GstElement * element, GstState * state,
1800 GstState * pending, GstClockTime timeout)
1802 GstStateChangeReturn ret;
1804 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "getting state");
1807 GST_ELEMENT_CLASS (parent_class)->get_state (element, state, pending,
1813 /***********************************************
1814 * Topologically sorted iterator
1815 * see http://en.wikipedia.org/wiki/Topological_sorting
1817 * For each element in the graph, an entry is kept in a HashTable
1818 * with its number of srcpad connections (degree).
1819 * We then change state of all elements without dependencies
1820 * (degree 0) and decrement the degree of all elements connected
1821 * on the sinkpads. When an element reaches degree 0, its state is
1823 * When all elements are handled the algorithm stops.
1825 typedef struct _GstBinSortIterator
1828 GQueue queue; /* elements queued for state change */
1829 GstBin *bin; /* bin we iterate */
1830 gint mode; /* adding or removing dependency */
1831 GstElement *best; /* next element with least dependencies */
1832 gint best_deg; /* best degree */
1833 GHashTable *hash; /* hashtable with element dependencies */
1834 gboolean dirty; /* we detected structure change */
1835 } GstBinSortIterator;
1838 gst_bin_sort_iterator_copy (const GstBinSortIterator * it,
1839 GstBinSortIterator * copy)
1841 GHashTableIter iter;
1842 gpointer key, value;
1844 copy->queue = it->queue;
1845 g_queue_foreach (©->queue, (GFunc) gst_object_ref, NULL);
1847 copy->bin = gst_object_ref (it->bin);
1849 copy->best = gst_object_ref (it->best);
1851 copy->hash = g_hash_table_new (NULL, NULL);
1852 g_hash_table_iter_init (&iter, it->hash);
1853 while (g_hash_table_iter_next (&iter, &key, &value))
1854 g_hash_table_insert (copy->hash, key, value);
1857 /* we add and subtract 1 to make sure we don't confuse NULL and 0 */
1858 #define HASH_SET_DEGREE(bit, elem, deg) \
1859 g_hash_table_replace (bit->hash, elem, GINT_TO_POINTER(deg+1))
1860 #define HASH_GET_DEGREE(bit, elem) \
1861 (GPOINTER_TO_INT(g_hash_table_lookup (bit->hash, elem))-1)
1863 /* add element to queue of next elements in the iterator.
1864 * We push at the tail to give higher priority elements a
1867 add_to_queue (GstBinSortIterator * bit, GstElement * element)
1869 GST_DEBUG_OBJECT (bit->bin, "adding '%s' to queue",
1870 GST_ELEMENT_NAME (element));
1871 gst_object_ref (element);
1872 g_queue_push_tail (&bit->queue, element);
1873 HASH_SET_DEGREE (bit, element, -1);
1877 remove_from_queue (GstBinSortIterator * bit, GstElement * element)
1881 if ((find = g_queue_find (&bit->queue, element))) {
1882 GST_DEBUG_OBJECT (bit->bin, "removing '%s' from queue",
1883 GST_ELEMENT_NAME (element));
1885 g_queue_delete_link (&bit->queue, find);
1886 gst_object_unref (element);
1888 GST_DEBUG_OBJECT (bit->bin, "unable to remove '%s' from queue",
1889 GST_ELEMENT_NAME (element));
1893 /* clear the queue, unref all objects as we took a ref when
1894 * we added them to the queue */
1896 clear_queue (GQueue * queue)
1900 while ((p = g_queue_pop_head (queue)))
1901 gst_object_unref (p);
1904 /* set all degrees to 0. Elements marked as a sink are
1905 * added to the queue immediately. Since we only look at the SINK flag of the
1906 * element, it is possible that we add non-sinks to the queue. These will be
1907 * removed from the queue again when we can prove that it provides data for some
1910 reset_degree (GstElement * element, GstBinSortIterator * bit)
1914 /* sinks are added right away */
1915 GST_OBJECT_LOCK (element);
1916 is_sink = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_FLAG_SINK);
1917 GST_OBJECT_UNLOCK (element);
1920 add_to_queue (bit, element);
1922 /* others are marked with 0 and handled when sinks are done */
1923 HASH_SET_DEGREE (bit, element, 0);
1927 /* adjust the degree of all elements connected to the given
1928 * element. If a degree of an element drops to 0, it is
1929 * added to the queue of elements to schedule next.
1931 * We have to make sure not to cross the bin boundary this element
1935 update_degree (GstElement * element, GstBinSortIterator * bit)
1937 gboolean linked = FALSE;
1939 GST_OBJECT_LOCK (element);
1940 /* don't touch degree if element has no sinkpads */
1941 if (element->numsinkpads != 0) {
1942 /* loop over all sinkpads, decrement degree for all connected
1943 * elements in this bin */
1946 for (pads = element->sinkpads; pads; pads = g_list_next (pads)) {
1949 pad = GST_PAD_CAST (pads->data);
1951 /* we're iterating over the sinkpads, check if it's busy in a link/unlink */
1952 if (G_UNLIKELY (find_message (bit->bin, GST_OBJECT_CAST (pad),
1953 GST_MESSAGE_STRUCTURE_CHANGE))) {
1954 /* mark the iterator as dirty because we won't be updating the degree
1955 * of the peer parent now. This would result in the 'loop detected'
1956 * later on because the peer parent element could become the best next
1957 * element with a degree > 0. We will simply continue our state
1958 * changes and we'll eventually resync when the unlink completed and
1959 * the iterator cookie is updated. */
1964 if ((peer = gst_pad_get_peer (pad))) {
1965 GstElement *peer_element;
1967 if ((peer_element = gst_pad_get_parent_element (peer))) {
1968 GST_OBJECT_LOCK (peer_element);
1969 /* check that we don't go outside of this bin */
1970 if (GST_OBJECT_CAST (peer_element)->parent ==
1971 GST_OBJECT_CAST (bit->bin)) {
1972 gint old_deg, new_deg;
1974 old_deg = HASH_GET_DEGREE (bit, peer_element);
1976 /* check to see if we added an element as sink that was not really a
1977 * sink because it was connected to some other element. */
1978 if (old_deg == -1) {
1979 remove_from_queue (bit, peer_element);
1982 new_deg = old_deg + bit->mode;
1984 GST_DEBUG_OBJECT (bit->bin,
1985 "change element %s, degree %d->%d, linked to %s",
1986 GST_ELEMENT_NAME (peer_element), old_deg, new_deg,
1987 GST_ELEMENT_NAME (element));
1989 /* update degree, it is possible that an element was in 0 and
1990 * reaches -1 here. This would mean that the element had no sinkpads
1991 * but became linked while the state change was happening. We will
1992 * resync on this with the structure change message. */
1994 /* degree hit 0, add to queue */
1995 add_to_queue (bit, peer_element);
1997 HASH_SET_DEGREE (bit, peer_element, new_deg);
2001 GST_OBJECT_UNLOCK (peer_element);
2002 gst_object_unref (peer_element);
2004 gst_object_unref (peer);
2009 GST_DEBUG_OBJECT (bit->bin, "element %s not linked on any sinkpads",
2010 GST_ELEMENT_NAME (element));
2012 GST_OBJECT_UNLOCK (element);
2015 /* find the next best element not handled yet. This is the one
2016 * with the lowest non-negative degree */
2018 find_element (GstElement * element, GstBinSortIterator * bit)
2022 /* element is already handled */
2023 if ((degree = HASH_GET_DEGREE (bit, element)) < 0)
2026 /* first element or element with smaller degree */
2027 if (bit->best == NULL || bit->best_deg > degree) {
2028 bit->best = element;
2029 bit->best_deg = degree;
2033 /* get next element in iterator. the returned element has the
2034 * refcount increased */
2035 static GstIteratorResult
2036 gst_bin_sort_iterator_next (GstBinSortIterator * bit, GValue * result)
2039 GstBin *bin = bit->bin;
2041 /* empty queue, we have to find a next best element */
2042 if (g_queue_is_empty (&bit->queue)) {
2044 bit->best_deg = G_MAXINT;
2045 g_list_foreach (bin->children, (GFunc) find_element, bit);
2046 if ((best = bit->best)) {
2047 /* when we detected an unlink, don't warn because our degrees might be
2048 * screwed up. We will resync later */
2049 if (bit->best_deg != 0 && !bit->dirty) {
2050 /* we don't fail on this one yet */
2051 GST_WARNING_OBJECT (bin, "loop dected in graph");
2052 g_warning ("loop detected in the graph of bin '%s'!!",
2053 GST_ELEMENT_NAME (bin));
2055 /* best unhandled element, schedule as next element */
2056 GST_DEBUG_OBJECT (bin, "queue empty, next best: %s",
2057 GST_ELEMENT_NAME (best));
2058 HASH_SET_DEGREE (bit, best, -1);
2059 g_value_set_object (result, best);
2061 GST_DEBUG_OBJECT (bin, "queue empty, elements exhausted");
2062 /* no more unhandled elements, we are done */
2063 return GST_ITERATOR_DONE;
2066 /* everything added to the queue got reffed */
2067 best = g_queue_pop_head (&bit->queue);
2068 g_value_set_object (result, best);
2069 gst_object_unref (best);
2072 GST_DEBUG_OBJECT (bin, "queue head gives %s", GST_ELEMENT_NAME (best));
2073 /* update degrees of linked elements */
2074 update_degree (best, bit);
2076 return GST_ITERATOR_OK;
2079 /* clear queues, recalculate the degrees and restart. */
2081 gst_bin_sort_iterator_resync (GstBinSortIterator * bit)
2083 GstBin *bin = bit->bin;
2085 GST_DEBUG_OBJECT (bin, "resync");
2087 clear_queue (&bit->queue);
2089 g_list_foreach (bin->children, (GFunc) reset_degree, bit);
2090 /* calc degrees, incrementing */
2092 g_list_foreach (bin->children, (GFunc) update_degree, bit);
2093 /* for the rest of the function we decrement the degrees */
2097 /* clear queues, unref bin and free iterator. */
2099 gst_bin_sort_iterator_free (GstBinSortIterator * bit)
2101 GstBin *bin = bit->bin;
2103 GST_DEBUG_OBJECT (bin, "free");
2104 clear_queue (&bit->queue);
2105 g_hash_table_destroy (bit->hash);
2106 gst_object_unref (bin);
2109 /* should be called with the bin LOCK held */
2110 static GstIterator *
2111 gst_bin_sort_iterator_new (GstBin * bin)
2113 GstBinSortIterator *result;
2115 /* we don't need an ItemFunction because we ref the items in the _next
2117 result = (GstBinSortIterator *)
2118 gst_iterator_new (sizeof (GstBinSortIterator),
2120 GST_OBJECT_GET_LOCK (bin),
2121 &bin->priv->structure_cookie,
2122 (GstIteratorCopyFunction) gst_bin_sort_iterator_copy,
2123 (GstIteratorNextFunction) gst_bin_sort_iterator_next,
2124 (GstIteratorItemFunction) NULL,
2125 (GstIteratorResyncFunction) gst_bin_sort_iterator_resync,
2126 (GstIteratorFreeFunction) gst_bin_sort_iterator_free);
2127 g_queue_init (&result->queue);
2128 result->hash = g_hash_table_new (NULL, NULL);
2129 gst_object_ref (bin);
2131 gst_bin_sort_iterator_resync (result);
2133 return (GstIterator *) result;
2137 * gst_bin_iterate_sorted:
2140 * Gets an iterator for the elements in this bin in topologically
2141 * sorted order. This means that the elements are returned from
2142 * the most downstream elements (sinks) to the sources.
2144 * This function is used internally to perform the state changes
2145 * of the bin elements and for clock selection.
2147 * Each element yielded by the iterator will have its refcount increased, so
2150 * MT safe. Caller owns returned value.
2152 * Returns: (transfer full): a #GstIterator of #GstElement, or NULL
2155 gst_bin_iterate_sorted (GstBin * bin)
2157 GstIterator *result;
2159 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
2161 GST_OBJECT_LOCK (bin);
2162 result = gst_bin_sort_iterator_new (bin);
2163 GST_OBJECT_UNLOCK (bin);
2168 static GstStateChangeReturn
2169 gst_bin_element_set_state (GstBin * bin, GstElement * element,
2170 GstClockTime base_time, GstClockTime start_time, GstState current,
2173 GstStateChangeReturn ret;
2174 GstState child_current, child_pending;
2178 GST_STATE_LOCK (element);
2180 GST_OBJECT_LOCK (element);
2181 /* set base_time and start time on child */
2182 GST_ELEMENT_START_TIME (element) = start_time;
2183 element->base_time = base_time;
2184 /* peel off the locked flag */
2185 locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2186 /* Get the previous set_state result to preserve NO_PREROLL and ASYNC */
2187 ret = GST_STATE_RETURN (element);
2188 child_current = GST_STATE (element);
2189 child_pending = GST_STATE_PENDING (element);
2190 GST_OBJECT_UNLOCK (element);
2192 /* skip locked elements */
2193 if (G_UNLIKELY (locked))
2196 /* if the element was no preroll, just start changing the state regardless
2197 * if it had async elements (in the case of a bin) because they won't preroll
2199 if (G_UNLIKELY (ret == GST_STATE_CHANGE_NO_PREROLL)) {
2200 GST_DEBUG_OBJECT (element, "element is NO_PREROLL, ignore async elements");
2204 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2205 "current %s pending %s, desired next %s",
2206 gst_element_state_get_name (child_current),
2207 gst_element_state_get_name (child_pending),
2208 gst_element_state_get_name (next));
2210 /* always recurse into bins so that we can set the base time */
2211 if (GST_IS_BIN (element))
2214 /* Try not to change the state of elements that are already in the state we're
2216 if (child_current == next && child_pending == GST_STATE_VOID_PENDING) {
2217 /* child is already at the requested state, return previous return. Note that
2218 * if the child has a pending state to next, we will still call the
2219 * set_state function */
2221 } else if (next > current) {
2222 /* upward state change */
2223 if (child_pending == GST_STATE_VOID_PENDING) {
2224 /* .. and the child is not busy doing anything */
2225 if (child_current > next) {
2226 /* .. and is already past the requested state, assume it got there
2228 ret = GST_STATE_CHANGE_SUCCESS;
2231 } else if (child_pending > child_current) {
2232 /* .. and the child is busy going upwards */
2233 if (child_current >= next) {
2234 /* .. and is already past the requested state, assume it got there
2236 ret = GST_STATE_CHANGE_SUCCESS;
2240 /* .. and the child is busy going downwards */
2241 if (child_current > next) {
2242 /* .. and is already past the requested state, assume it got there
2244 ret = GST_STATE_CHANGE_SUCCESS;
2248 } else if (next < current) {
2249 /* downward state change */
2250 if (child_pending == GST_STATE_VOID_PENDING) {
2251 /* .. and the child is not busy doing anything */
2252 if (child_current < next) {
2253 /* .. and is already past the requested state, assume it got there
2255 ret = GST_STATE_CHANGE_SUCCESS;
2258 } else if (child_pending < child_current) {
2259 /* .. and the child is busy going downwards */
2260 if (child_current <= next) {
2261 /* .. and is already past the requested state, assume it got there
2263 ret = GST_STATE_CHANGE_SUCCESS;
2267 /* .. and the child is busy going upwards */
2268 if (child_current < next) {
2269 /* .. and is already past the requested state, assume it got there
2271 ret = GST_STATE_CHANGE_SUCCESS;
2278 GST_OBJECT_LOCK (bin);
2279 /* the element was busy with an upwards async state change, we must wait for
2280 * an ASYNC_DONE message before we attemp to change the state. */
2282 find_message (bin, GST_OBJECT_CAST (element),
2283 GST_MESSAGE_ASYNC_START))) {
2284 #ifndef GST_DISABLE_GST_DEBUG
2285 GstMessage *message = GST_MESSAGE_CAST (found->data);
2287 GST_DEBUG_OBJECT (element, "element message %p, %s async busy",
2288 message, GST_ELEMENT_NAME (GST_MESSAGE_SRC (message)));
2290 /* only wait for upward state changes */
2291 if (next > current) {
2292 /* We found an async element check if we can force its state to change or
2293 * if we have to wait for it to preroll. */
2297 GST_OBJECT_UNLOCK (bin);
2300 GST_DEBUG_OBJECT (bin,
2301 "setting element %s to %s, base_time %" GST_TIME_FORMAT,
2302 GST_ELEMENT_NAME (element), gst_element_state_get_name (next),
2303 GST_TIME_ARGS (base_time));
2306 ret = gst_element_set_state (element, next);
2308 GST_STATE_UNLOCK (element);
2314 GST_DEBUG_OBJECT (element,
2315 "element is locked, return previous return %s",
2316 gst_element_state_change_return_get_name (ret));
2317 GST_STATE_UNLOCK (element);
2322 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2323 "skipping transition from %s to %s",
2324 gst_element_state_get_name (child_current),
2325 gst_element_state_get_name (next));
2326 GST_STATE_UNLOCK (element);
2331 GST_DEBUG_OBJECT (element, "element was busy, delaying state change");
2332 GST_OBJECT_UNLOCK (bin);
2333 GST_STATE_UNLOCK (element);
2334 return GST_STATE_CHANGE_ASYNC;
2338 /* gst_iterator_fold functions for pads_activate
2339 * Stop the iterator if activating one pad failed. */
2341 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2343 GstPad *pad = g_value_get_object (vpad);
2344 gboolean cont = TRUE;
2346 if (!(cont = gst_pad_set_active (pad, *active)))
2347 g_value_set_boolean (ret, FALSE);
2352 /* returns false on error or early cutout of the fold, true if all
2353 * pads in @iter were (de)activated successfully. */
2355 iterator_activate_fold_with_resync (GstIterator * iter, gpointer user_data)
2357 GstIteratorResult ires;
2360 /* no need to unset this later, it's just a boolean */
2361 g_value_init (&ret, G_TYPE_BOOLEAN);
2362 g_value_set_boolean (&ret, TRUE);
2365 ires = gst_iterator_fold (iter, (GstIteratorFoldFunction) activate_pads,
2368 case GST_ITERATOR_RESYNC:
2369 /* need to reset the result again */
2370 g_value_set_boolean (&ret, TRUE);
2371 gst_iterator_resync (iter);
2373 case GST_ITERATOR_DONE:
2374 /* all pads iterated, return collected value */
2377 /* iterator returned _ERROR or premature end with _OK,
2378 * mark an error and exit */
2379 g_value_set_boolean (&ret, FALSE);
2384 /* return collected value */
2385 return g_value_get_boolean (&ret);
2388 /* is called with STATE_LOCK
2391 gst_bin_src_pads_activate (GstBin * bin, gboolean active)
2396 GST_DEBUG_OBJECT (bin, "%s pads", active ? "activate" : "deactivate");
2398 iter = gst_element_iterate_src_pads ((GstElement *) bin);
2399 fold_ok = iterator_activate_fold_with_resync (iter, &active);
2400 gst_iterator_free (iter);
2401 if (G_UNLIKELY (!fold_ok))
2404 GST_DEBUG_OBJECT (bin, "pad %sactivation successful", active ? "" : "de");
2411 GST_DEBUG_OBJECT (bin, "pad %sactivation failed", active ? "" : "de");
2417 * gst_bin_recalculate_latency:
2420 * Query @bin for the current latency using and reconfigures this latency to all the
2421 * elements with a LATENCY event.
2423 * This method is typically called on the pipeline when a #GST_MESSAGE_LATENCY
2424 * is posted on the bus.
2426 * This function simply emits the 'do-latency' signal so any custom latency
2427 * calculations will be performed.
2429 * Returns: %TRUE if the latency could be queried and reconfigured.
2432 gst_bin_recalculate_latency (GstBin * bin)
2436 g_signal_emit (bin, gst_bin_signals[DO_LATENCY], 0, &res);
2437 GST_DEBUG_OBJECT (bin, "latency returned %d", res);
2443 gst_bin_do_latency_func (GstBin * bin)
2446 GstElement *element;
2447 GstClockTime min_latency, max_latency;
2450 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
2452 element = GST_ELEMENT_CAST (bin);
2454 GST_DEBUG_OBJECT (element, "querying latency");
2456 query = gst_query_new_latency ();
2457 if ((res = gst_element_query (element, query))) {
2460 gst_query_parse_latency (query, &live, &min_latency, &max_latency);
2462 GST_DEBUG_OBJECT (element,
2463 "got min latency %" GST_TIME_FORMAT ", max latency %"
2464 GST_TIME_FORMAT ", live %d", GST_TIME_ARGS (min_latency),
2465 GST_TIME_ARGS (max_latency), live);
2467 if (max_latency < min_latency) {
2468 /* this is an impossible situation, some parts of the pipeline might not
2469 * work correctly. We post a warning for now. */
2470 GST_ELEMENT_WARNING (element, CORE, CLOCK, (NULL),
2471 ("Impossible to configure latency: max %" GST_TIME_FORMAT " < min %"
2472 GST_TIME_FORMAT ". Add queues or other buffering elements.",
2473 GST_TIME_ARGS (max_latency), GST_TIME_ARGS (min_latency)));
2476 /* configure latency on elements */
2477 res = gst_element_send_event (element, gst_event_new_latency (min_latency));
2479 GST_INFO_OBJECT (element, "configured latency of %" GST_TIME_FORMAT,
2480 GST_TIME_ARGS (min_latency));
2482 GST_WARNING_OBJECT (element,
2483 "did not really configure latency of %" GST_TIME_FORMAT,
2484 GST_TIME_ARGS (min_latency));
2487 /* this is not a real problem, we just don't configure any latency. */
2488 GST_WARNING_OBJECT (element, "failed to query latency");
2490 gst_query_unref (query);
2496 gst_bin_state_changed (GstElement * element, GstState oldstate,
2497 GstState newstate, GstState pending)
2499 GstElementClass *pklass = (GstElementClass *) parent_class;
2501 if (newstate == GST_STATE_PLAYING && pending == GST_STATE_VOID_PENDING)
2502 bin_do_eos (GST_BIN_CAST (element));
2504 if (pklass->state_changed)
2505 pklass->state_changed (element, oldstate, newstate, pending);
2508 static GstStateChangeReturn
2509 gst_bin_change_state_func (GstElement * element, GstStateChange transition)
2512 GstStateChangeReturn ret;
2513 GstState current, next;
2514 gboolean have_async;
2515 gboolean have_no_preroll;
2516 GstClockTime base_time, start_time;
2519 GValue data = { 0, };
2521 /* we don't need to take the STATE_LOCK, it is already taken */
2522 current = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2523 next = (GstState) GST_STATE_TRANSITION_NEXT (transition);
2525 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2526 "changing state of children from %s to %s",
2527 gst_element_state_get_name (current), gst_element_state_get_name (next));
2529 bin = GST_BIN_CAST (element);
2532 case GST_STATE_PLAYING:
2536 GST_OBJECT_LOCK (bin);
2537 toplevel = BIN_IS_TOPLEVEL (bin);
2538 GST_OBJECT_UNLOCK (bin);
2541 gst_bin_recalculate_latency (bin);
2544 case GST_STATE_PAUSED:
2545 /* Clear EOS list on next PAUSED */
2546 GST_OBJECT_LOCK (bin);
2547 GST_DEBUG_OBJECT (element, "clearing EOS elements");
2548 bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
2549 bin->priv->posted_eos = FALSE;
2550 if (current == GST_STATE_READY)
2551 bin_remove_messages (bin, NULL, GST_MESSAGE_STREAM_START);
2552 GST_OBJECT_UNLOCK (bin);
2553 if (current == GST_STATE_READY)
2554 if (!(gst_bin_src_pads_activate (bin, TRUE)))
2555 goto activate_failure;
2557 case GST_STATE_READY:
2558 /* Clear message list on next READY */
2559 GST_OBJECT_LOCK (bin);
2560 GST_DEBUG_OBJECT (element, "clearing all cached messages");
2561 bin_remove_messages (bin, NULL, GST_MESSAGE_ANY);
2562 GST_OBJECT_UNLOCK (bin);
2563 if (current == GST_STATE_PAUSED)
2564 if (!(gst_bin_src_pads_activate (bin, FALSE)))
2565 goto activate_failure;
2567 case GST_STATE_NULL:
2568 if (current == GST_STATE_READY)
2569 if (!(gst_bin_src_pads_activate (bin, FALSE)))
2570 goto activate_failure;
2576 /* this flag is used to make the async state changes return immediately. We
2577 * don't want them to interfere with this state change */
2578 GST_OBJECT_LOCK (bin);
2579 bin->polling = TRUE;
2580 GST_OBJECT_UNLOCK (bin);
2582 /* iterate in state change order */
2583 it = gst_bin_iterate_sorted (bin);
2585 /* mark if we've seen an ASYNC element in the bin when we did a state change.
2586 * Note how we don't reset this value when a resync happens, the reason being
2587 * that the async element posted ASYNC_START and we want to post ASYNC_DONE
2588 * even after a resync when the async element is gone */
2592 /* take base_time */
2593 base_time = gst_element_get_base_time (element);
2594 start_time = gst_element_get_start_time (element);
2596 have_no_preroll = FALSE;
2600 switch (gst_iterator_next (it, &data)) {
2601 case GST_ITERATOR_OK:
2605 child = g_value_get_object (&data);
2607 /* set state and base_time now */
2608 ret = gst_bin_element_set_state (bin, child, base_time, start_time,
2612 case GST_STATE_CHANGE_SUCCESS:
2613 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2614 "child '%s' changed state to %d(%s) successfully",
2615 GST_ELEMENT_NAME (child), next,
2616 gst_element_state_get_name (next));
2618 case GST_STATE_CHANGE_ASYNC:
2620 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2621 "child '%s' is changing state asynchronously to %s",
2622 GST_ELEMENT_NAME (child), gst_element_state_get_name (next));
2626 case GST_STATE_CHANGE_FAILURE:{
2629 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2630 "child '%s' failed to go to state %d(%s)",
2631 GST_ELEMENT_NAME (child),
2632 next, gst_element_state_get_name (next));
2634 /* Only fail if the child is still inside
2635 * this bin. It might've been removed already
2636 * because of the error by the bin subclass
2637 * to ignore the error. */
2638 parent = gst_object_get_parent (GST_OBJECT_CAST (child));
2639 if (parent == GST_OBJECT_CAST (element)) {
2640 /* element is still in bin, really error now */
2641 gst_object_unref (parent);
2644 /* child removed from bin, let the resync code redo the state
2646 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2647 "child '%s' was removed from the bin",
2648 GST_ELEMENT_NAME (child));
2651 gst_object_unref (parent);
2655 case GST_STATE_CHANGE_NO_PREROLL:
2656 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2657 "child '%s' changed state to %d(%s) successfully without preroll",
2658 GST_ELEMENT_NAME (child), next,
2659 gst_element_state_get_name (next));
2660 have_no_preroll = TRUE;
2663 g_assert_not_reached ();
2666 g_value_reset (&data);
2669 case GST_ITERATOR_RESYNC:
2670 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "iterator doing resync");
2671 gst_iterator_resync (it);
2674 case GST_ITERATOR_DONE:
2675 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "iterator done");
2681 ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
2682 if (G_UNLIKELY (ret == GST_STATE_CHANGE_FAILURE))
2685 if (have_no_preroll) {
2686 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
2687 "we have NO_PREROLL elements %s -> NO_PREROLL",
2688 gst_element_state_change_return_get_name (ret));
2689 ret = GST_STATE_CHANGE_NO_PREROLL;
2690 } else if (have_async) {
2691 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
2692 "we have ASYNC elements %s -> ASYNC",
2693 gst_element_state_change_return_get_name (ret));
2694 ret = GST_STATE_CHANGE_ASYNC;
2698 g_value_unset (&data);
2699 gst_iterator_free (it);
2701 GST_OBJECT_LOCK (bin);
2702 bin->polling = FALSE;
2703 /* it's possible that we did not get ASYNC from the children while the bin is
2704 * simulating ASYNC behaviour by posting an ASYNC_DONE message on the bus with
2705 * itself as the source. In that case we still want to check if the state
2706 * change completed. */
2707 if (ret != GST_STATE_CHANGE_ASYNC && !bin->priv->pending_async_done) {
2708 /* no element returned ASYNC and there are no pending async_done messages,
2709 * we can just complete. */
2710 GST_DEBUG_OBJECT (bin, "no async elements");
2713 /* when we get here an ASYNC element was found */
2714 if (GST_STATE_TARGET (bin) <= GST_STATE_READY) {
2715 /* we ignore ASYNC state changes when we go to READY or NULL */
2716 GST_DEBUG_OBJECT (bin, "target state %s <= READY",
2717 gst_element_state_get_name (GST_STATE_TARGET (bin)));
2721 GST_DEBUG_OBJECT (bin, "check async elements");
2722 /* check if all elements managed to commit their state already */
2723 if (!find_message (bin, NULL, GST_MESSAGE_ASYNC_START)) {
2724 /* nothing found, remove all old ASYNC_DONE messages. This can happen when
2725 * all the elements commited their state while we were doing the state
2726 * change. We will still return ASYNC for consistency but we commit the
2727 * state already so that a _get_state() will return immediately. */
2728 bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
2730 GST_DEBUG_OBJECT (bin, "async elements commited");
2731 bin_handle_async_done (bin, GST_STATE_CHANGE_SUCCESS, FALSE,
2732 GST_CLOCK_TIME_NONE);
2736 bin->priv->pending_async_done = FALSE;
2737 GST_OBJECT_UNLOCK (bin);
2739 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2740 "done changing bin's state from %s to %s, now in %s, ret %s",
2741 gst_element_state_get_name (current),
2742 gst_element_state_get_name (next),
2743 gst_element_state_get_name (GST_STATE (element)),
2744 gst_element_state_change_return_get_name (ret));
2751 GST_CAT_WARNING_OBJECT (GST_CAT_STATES, element,
2752 "failure (de)activating src pads");
2753 return GST_STATE_CHANGE_FAILURE;
2758 * This function is a utility event handler for seek events.
2759 * It will send the event to all sinks or sources depending on the
2762 * Applications are free to override this behaviour and
2763 * implement their own seek handler, but this will work for
2764 * pretty much all cases in practice.
2767 gst_bin_send_event (GstElement * element, GstEvent * event)
2769 GstBin *bin = GST_BIN_CAST (element);
2771 gboolean res = TRUE;
2772 gboolean done = FALSE;
2773 GValue data = { 0, };
2775 if (GST_EVENT_IS_DOWNSTREAM (event)) {
2776 iter = gst_bin_iterate_sources (bin);
2777 GST_DEBUG_OBJECT (bin, "Sending %s event to src children",
2778 GST_EVENT_TYPE_NAME (event));
2780 iter = gst_bin_iterate_sinks (bin);
2781 GST_DEBUG_OBJECT (bin, "Sending %s event to sink children",
2782 GST_EVENT_TYPE_NAME (event));
2786 switch (gst_iterator_next (iter, &data)) {
2787 case GST_ITERATOR_OK:
2789 GstElement *child = g_value_get_object (&data);;
2791 gst_event_ref (event);
2792 res &= gst_element_send_event (child, event);
2793 GST_LOG_OBJECT (child, "After handling %s event: %d",
2794 GST_EVENT_TYPE_NAME (event), res);
2797 case GST_ITERATOR_RESYNC:
2798 gst_iterator_resync (iter);
2801 case GST_ITERATOR_DONE:
2804 case GST_ITERATOR_ERROR:
2805 g_assert_not_reached ();
2809 g_value_unset (&data);
2810 gst_iterator_free (iter);
2811 gst_event_unref (event);
2816 /* this is the function called by the threadpool. When async elements commit
2817 * their state, this function will attempt to bring the bin to the next state.
2820 gst_bin_continue_func (BinContinueData * data)
2823 GstState current, next, pending;
2824 GstStateChange transition;
2827 pending = data->pending;
2829 GST_DEBUG_OBJECT (bin, "waiting for state lock");
2830 GST_STATE_LOCK (bin);
2832 GST_DEBUG_OBJECT (bin, "doing state continue");
2833 GST_OBJECT_LOCK (bin);
2835 /* if a new state change happened after this thread was scheduled, we return
2837 if (data->cookie != GST_ELEMENT_CAST (bin)->state_cookie)
2840 current = GST_STATE (bin);
2841 next = GST_STATE_GET_NEXT (current, pending);
2842 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2844 GST_STATE_NEXT (bin) = next;
2845 GST_STATE_PENDING (bin) = pending;
2847 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
2848 GST_OBJECT_UNLOCK (bin);
2850 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
2851 "continue state change %s to %s, final %s",
2852 gst_element_state_get_name (current),
2853 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2855 gst_element_change_state (GST_ELEMENT_CAST (bin), transition);
2857 GST_STATE_UNLOCK (bin);
2858 GST_DEBUG_OBJECT (bin, "state continue done");
2860 gst_object_unref (bin);
2861 g_slice_free (BinContinueData, data);
2866 GST_OBJECT_UNLOCK (bin);
2867 GST_STATE_UNLOCK (bin);
2868 GST_DEBUG_OBJECT (bin, "state continue aborted due to intervening change");
2869 gst_object_unref (bin);
2870 g_slice_free (BinContinueData, data);
2875 static GstBusSyncReply
2876 bin_bus_handler (GstBus * bus, GstMessage * message, GstBin * bin)
2878 GstBinClass *bclass;
2880 bclass = GST_BIN_GET_CLASS (bin);
2881 if (bclass->handle_message)
2882 bclass->handle_message (bin, message);
2884 gst_message_unref (message);
2886 return GST_BUS_DROP;
2890 bin_push_state_continue (BinContinueData * data)
2897 klass = GST_BIN_GET_CLASS (bin);
2899 GST_DEBUG_OBJECT (bin, "pushing continue on thread pool");
2900 g_thread_pool_push (klass->pool, data, NULL);
2903 /* an element started an async state change, if we were not busy with a state
2904 * change, we perform a lost state.
2905 * This function is called with the OBJECT lock.
2908 bin_handle_async_start (GstBin * bin)
2910 GstState old_state, new_state;
2912 GstMessage *amessage = NULL;
2914 if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
2917 /* get our toplevel state */
2918 toplevel = BIN_IS_TOPLEVEL (bin);
2920 /* prepare an ASYNC_START message, we always post the start message even if we
2921 * are busy with a state change or when we are NO_PREROLL. */
2923 /* non toplevel bin, prepare async-start for the parent */
2924 amessage = gst_message_new_async_start (GST_OBJECT_CAST (bin));
2926 if (bin->polling || GST_STATE_PENDING (bin) != GST_STATE_VOID_PENDING)
2929 /* async starts are ignored when we are NO_PREROLL */
2930 if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_NO_PREROLL)
2931 goto was_no_preroll;
2933 old_state = GST_STATE (bin);
2935 /* when we PLAYING we go back to PAUSED, when preroll happens, we go back to
2936 * PLAYING after optionally redistributing the base_time. */
2937 if (old_state > GST_STATE_PAUSED)
2938 new_state = GST_STATE_PAUSED;
2940 new_state = old_state;
2942 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
2943 "lost state of %s, new %s", gst_element_state_get_name (old_state),
2944 gst_element_state_get_name (new_state));
2946 GST_STATE (bin) = new_state;
2947 GST_STATE_NEXT (bin) = new_state;
2948 GST_STATE_PENDING (bin) = new_state;
2949 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
2950 GST_OBJECT_UNLOCK (bin);
2953 _priv_gst_element_state_changed (GST_ELEMENT_CAST (bin), new_state, new_state,
2958 /* post our ASYNC_START. */
2959 GST_DEBUG_OBJECT (bin, "posting ASYNC_START to parent");
2960 gst_element_post_message (GST_ELEMENT_CAST (bin), amessage);
2962 GST_OBJECT_LOCK (bin);
2968 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
2973 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
2974 GST_OBJECT_UNLOCK (bin);
2979 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "ignoring, we are NO_PREROLL");
2980 GST_OBJECT_UNLOCK (bin);
2985 /* this function is called when there are no more async elements in the bin. We
2986 * post a state changed message and an ASYNC_DONE message.
2987 * This function is called with the OBJECT lock.
2990 bin_handle_async_done (GstBin * bin, GstStateChangeReturn ret,
2991 gboolean flag_pending, GstClockTime running_time)
2993 GstState current, pending, target;
2994 GstStateChangeReturn old_ret;
2995 GstState old_state, old_next;
2996 gboolean toplevel, state_changed = FALSE;
2997 GstMessage *amessage = NULL;
2998 BinContinueData *cont = NULL;
3000 if (GST_STATE_RETURN (bin) == GST_STATE_CHANGE_FAILURE)
3003 pending = GST_STATE_PENDING (bin);
3008 /* check if there is something to commit */
3009 if (pending == GST_STATE_VOID_PENDING)
3010 goto nothing_pending;
3012 old_ret = GST_STATE_RETURN (bin);
3013 GST_STATE_RETURN (bin) = ret;
3015 /* move to the next target state */
3016 target = GST_STATE_TARGET (bin);
3017 pending = GST_STATE_PENDING (bin) = target;
3019 amessage = gst_message_new_async_done (GST_OBJECT_CAST (bin), running_time);
3021 old_state = GST_STATE (bin);
3022 /* this is the state we should go to next */
3023 old_next = GST_STATE_NEXT (bin);
3025 if (old_next != GST_STATE_PLAYING) {
3026 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3027 "committing state from %s to %s, old pending %s",
3028 gst_element_state_get_name (old_state),
3029 gst_element_state_get_name (old_next),
3030 gst_element_state_get_name (pending));
3032 /* update current state */
3033 current = GST_STATE (bin) = old_next;
3035 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3036 "setting state from %s to %s, pending %s",
3037 gst_element_state_get_name (old_state),
3038 gst_element_state_get_name (old_state),
3039 gst_element_state_get_name (pending));
3040 current = old_state;
3043 /* get our toplevel state */
3044 toplevel = BIN_IS_TOPLEVEL (bin);
3046 /* see if we reached the final state. If we are not toplevel, we also have to
3047 * stop here, the parent will continue our state. */
3048 if ((pending == current) || !toplevel) {
3049 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3050 "completed state change, pending VOID");
3052 /* mark VOID pending */
3053 pending = GST_STATE_VOID_PENDING;
3054 GST_STATE_PENDING (bin) = pending;
3055 GST_STATE_NEXT (bin) = GST_STATE_VOID_PENDING;
3057 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin,
3058 "continue state change, pending %s",
3059 gst_element_state_get_name (pending));
3061 cont = g_slice_new (BinContinueData);
3063 /* ref to the bin */
3064 cont->bin = gst_object_ref (bin);
3065 /* cookie to detect concurrent state change */
3066 cont->cookie = GST_ELEMENT_CAST (bin)->state_cookie;
3067 /* pending target state */
3068 cont->pending = pending;
3070 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_ASYNC;
3071 GST_STATE_NEXT (bin) = GST_STATE_GET_NEXT (old_state, pending);
3074 if (old_next != GST_STATE_PLAYING) {
3075 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
3076 state_changed = TRUE;
3079 GST_OBJECT_UNLOCK (bin);
3081 if (state_changed) {
3082 _priv_gst_element_state_changed (GST_ELEMENT_CAST (bin), old_state,
3086 /* post our combined ASYNC_DONE when all is ASYNC_DONE. */
3087 GST_DEBUG_OBJECT (bin, "posting ASYNC_DONE to parent");
3088 gst_element_post_message (GST_ELEMENT_CAST (bin), amessage);
3091 GST_OBJECT_LOCK (bin);
3093 /* toplevel, start continue state */
3094 GST_DEBUG_OBJECT (bin, "all async-done, starting state continue");
3095 bin_push_state_continue (cont);
3097 GST_DEBUG_OBJECT (bin, "state change complete");
3098 GST_STATE_BROADCAST (bin);
3104 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "we had an error");
3109 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin, "state change busy");
3110 /* if we were busy with a state change and we are requested to flag a
3111 * pending async done, we do so here */
3113 bin->priv->pending_async_done = TRUE;
3118 GST_CAT_INFO_OBJECT (GST_CAT_STATES, bin, "nothing pending");
3124 bin_do_eos (GstBin * bin)
3129 GST_OBJECT_LOCK (bin);
3130 /* If all sinks are EOS, we're in PLAYING and no state change is pending
3131 * we forward the EOS message to the parent bin or application
3133 eos = GST_STATE (bin) == GST_STATE_PLAYING
3134 && GST_STATE_PENDING (bin) == GST_STATE_VOID_PENDING
3135 && is_eos (bin, &seqnum);
3136 GST_OBJECT_UNLOCK (bin);
3139 && g_atomic_int_compare_and_exchange (&bin->priv->posted_eos, FALSE,
3141 GstMessage *tmessage;
3143 /* Clear out any further messages, and reset posted_eos so we can
3144 detect any new EOS that happens (eg, after a seek). Since all
3145 sinks have now posted an EOS, there will be no further EOS events
3146 seen unless there is a new logical EOS */
3147 GST_OBJECT_LOCK (bin);
3148 bin_remove_messages (bin, NULL, GST_MESSAGE_EOS);
3149 bin->priv->posted_eos = FALSE;
3150 GST_OBJECT_UNLOCK (bin);
3152 tmessage = gst_message_new_eos (GST_OBJECT_CAST (bin));
3153 gst_message_set_seqnum (tmessage, seqnum);
3154 GST_DEBUG_OBJECT (bin,
3155 "all sinks posted EOS, posting seqnum #%" G_GUINT32_FORMAT, seqnum);
3156 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3161 bin_do_stream_start (GstBin * bin)
3164 gboolean stream_start;
3166 GST_OBJECT_LOCK (bin);
3167 /* If all sinks are STREAM_START we forward the STREAM_START message
3168 * to the parent bin or application
3170 stream_start = is_stream_start (bin, &seqnum);
3171 GST_OBJECT_UNLOCK (bin);
3174 GstMessage *tmessage;
3176 GST_OBJECT_LOCK (bin);
3177 bin_remove_messages (bin, NULL, GST_MESSAGE_STREAM_START);
3178 GST_OBJECT_UNLOCK (bin);
3180 tmessage = gst_message_new_stream_start (GST_OBJECT_CAST (bin));
3181 gst_message_set_seqnum (tmessage, seqnum);
3182 GST_DEBUG_OBJECT (bin,
3183 "all sinks posted STREAM_START, posting seqnum #%" G_GUINT32_FORMAT,
3185 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3189 /* must be called with the object lock. This function releases the lock to post
3192 bin_do_message_forward (GstBin * bin, GstMessage * message)
3194 if (bin->priv->message_forward) {
3195 GstMessage *forwarded;
3197 GST_DEBUG_OBJECT (bin, "pass %s message upward",
3198 GST_MESSAGE_TYPE_NAME (message));
3199 GST_OBJECT_UNLOCK (bin);
3201 /* we need to convert these messages to element messages so that our parent
3202 * bin can easily ignore them and so that the application can easily
3203 * distinguish between the internally forwarded and the real messages. */
3204 forwarded = gst_message_new_element (GST_OBJECT_CAST (bin),
3205 gst_structure_new ("GstBinForwarded",
3206 "message", GST_TYPE_MESSAGE, message, NULL));
3208 gst_element_post_message (GST_ELEMENT_CAST (bin), forwarded);
3210 GST_OBJECT_LOCK (bin);
3214 /* handle child messages:
3216 * This method is called synchronously when a child posts a message on
3219 * GST_MESSAGE_EOS: This message is only posted by sinks
3220 * in the PLAYING state. If all sinks posted the EOS message, post
3223 * GST_MESSAGE_STATE_DIRTY: Deprecated
3225 * GST_MESSAGE_SEGMENT_START: just collect, never forward upwards. If an
3226 * element posts segment_start twice, only the last message is kept.
3228 * GST_MESSAGE_SEGMENT_DONE: replace SEGMENT_START message from same poster
3229 * with the segment_done message. If there are no more segment_start
3230 * messages, post segment_done message upwards.
3232 * GST_MESSAGE_DURATION_CHANGED: clear any cached durations.
3233 * Whenever someone performs a duration query on the bin, we store the
3234 * result so we can answer it quicker the next time. Any element that
3235 * changes its duration marks our cached values invalid.
3236 * This message is also posted upwards. This is currently disabled
3237 * because too many elements don't post DURATION messages when the
3240 * GST_MESSAGE_CLOCK_LOST: This message is posted by an element when it
3241 * can no longer provide a clock. The default bin behaviour is to
3242 * check if the lost clock was the one provided by the bin. If so and
3243 * we are currently in the PLAYING state, we forward the message to
3245 * This message is also generated when we remove a clock provider from
3246 * a bin. If this message is received by the application, it should
3247 * PAUSE the pipeline and set it back to PLAYING to force a new clock
3248 * and a new base_time distribution.
3250 * GST_MESSAGE_CLOCK_PROVIDE: This message is generated when an element
3251 * can provide a clock. This mostly happens when we add a new clock
3252 * provider to the bin. The default behaviour of the bin is to mark the
3253 * currently selected clock as dirty, which will perform a clock
3254 * recalculation the next time we are asked to provide a clock.
3255 * This message is never sent to the application but is forwarded to
3258 * GST_MESSAGE_ASYNC_START: Create an internal ELEMENT message that stores
3259 * the state of the element and the fact that the element will need a
3260 * new base_time. This message is not forwarded to the application.
3262 * GST_MESSAGE_ASYNC_DONE: Find the internal ELEMENT message we kept for the
3263 * element when it posted ASYNC_START. If all elements are done, post a
3264 * ASYNC_DONE message to the parent.
3266 * OTHER: post upwards.
3269 gst_bin_handle_message_func (GstBin * bin, GstMessage * message)
3272 GstMessageType type;
3273 GstMessage *tmessage;
3276 src = GST_MESSAGE_SRC (message);
3277 type = GST_MESSAGE_TYPE (message);
3279 GST_DEBUG_OBJECT (bin, "[msg %p] handling child %s message of type %s",
3280 message, src ? GST_ELEMENT_NAME (src) : "(NULL)",
3281 GST_MESSAGE_TYPE_NAME (message));
3284 case GST_MESSAGE_ERROR:
3286 GST_OBJECT_LOCK (bin);
3288 GST_DEBUG_OBJECT (bin, "got ERROR message, unlocking state change");
3289 GST_STATE_RETURN (bin) = GST_STATE_CHANGE_FAILURE;
3290 GST_STATE_BROADCAST (bin);
3291 GST_OBJECT_UNLOCK (bin);
3295 case GST_MESSAGE_EOS:
3298 /* collect all eos messages from the children */
3299 GST_OBJECT_LOCK (bin);
3300 bin_do_message_forward (bin, message);
3301 /* ref message for future use */
3302 bin_replace_message (bin, message, GST_MESSAGE_EOS);
3303 GST_OBJECT_UNLOCK (bin);
3308 case GST_MESSAGE_STREAM_START:
3311 /* collect all stream_start messages from the children */
3312 GST_OBJECT_LOCK (bin);
3313 /* ref message for future use */
3314 bin_replace_message (bin, message, GST_MESSAGE_STREAM_START);
3315 GST_OBJECT_UNLOCK (bin);
3317 bin_do_stream_start (bin);
3320 case GST_MESSAGE_STATE_DIRTY:
3322 GST_WARNING_OBJECT (bin, "received deprecated STATE_DIRTY message");
3325 gst_message_unref (message);
3328 case GST_MESSAGE_SEGMENT_START:{
3329 gboolean post = FALSE;
3333 gst_message_parse_segment_start (message, &format, &position);
3334 seqnum = gst_message_get_seqnum (message);
3336 GST_OBJECT_LOCK (bin);
3337 bin_do_message_forward (bin, message);
3338 /* if this is the first segment-start, post to parent but not to the
3340 if (!find_message (bin, NULL, GST_MESSAGE_SEGMENT_START) &&
3341 (GST_OBJECT_PARENT (bin) != NULL)) {
3344 /* replace any previous segment_start message from this source
3345 * with the new segment start message */
3346 bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
3347 GST_OBJECT_UNLOCK (bin);
3349 tmessage = gst_message_new_segment_start (GST_OBJECT_CAST (bin),
3351 gst_message_set_seqnum (tmessage, seqnum);
3353 /* post segment start with initial format and position. */
3354 GST_DEBUG_OBJECT (bin, "posting SEGMENT_START (%u) bus message: %p",
3356 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3360 case GST_MESSAGE_SEGMENT_DONE:
3362 gboolean post = FALSE;
3366 gst_message_parse_segment_done (message, &format, &position);
3367 seqnum = gst_message_get_seqnum (message);
3369 GST_OBJECT_LOCK (bin);
3370 bin_do_message_forward (bin, message);
3371 bin_replace_message (bin, message, GST_MESSAGE_SEGMENT_START);
3372 /* if there are no more segment_start messages, everybody posted
3373 * a segment_done and we can post one on the bus. */
3375 /* we don't care who still has a pending segment start */
3376 if (!find_message (bin, NULL, GST_MESSAGE_SEGMENT_START)) {
3379 /* remove all old segment_done messages */
3380 bin_remove_messages (bin, NULL, GST_MESSAGE_SEGMENT_DONE);
3382 GST_OBJECT_UNLOCK (bin);
3384 tmessage = gst_message_new_segment_done (GST_OBJECT_CAST (bin),
3386 gst_message_set_seqnum (tmessage, seqnum);
3388 /* post segment done with latest format and position. */
3389 GST_DEBUG_OBJECT (bin, "posting SEGMENT_DONE (%u) bus message: %p",
3391 gst_element_post_message (GST_ELEMENT_CAST (bin), tmessage);
3395 case GST_MESSAGE_DURATION_CHANGED:
3397 /* FIXME: remove all cached durations, next time somebody asks
3398 * for duration, we will recalculate. */
3400 GST_OBJECT_LOCK (bin);
3401 bin_remove_messages (bin, NULL, GST_MESSAGE_DURATION);
3402 GST_OBJECT_UNLOCK (bin);
3406 case GST_MESSAGE_CLOCK_LOST:
3408 GstClock **provided_clock_p;
3409 GstElement **clock_provider_p;
3410 gboolean playing, provided, forward;
3413 gst_message_parse_clock_lost (message, &clock);
3415 GST_OBJECT_LOCK (bin);
3416 bin->clock_dirty = TRUE;
3417 /* if we lost the clock that we provided, post to parent but
3418 * only if we are PLAYING. */
3419 provided = (clock == bin->provided_clock);
3420 playing = (GST_STATE (bin) == GST_STATE_PLAYING);
3421 forward = playing & provided;
3423 GST_DEBUG_OBJECT (bin,
3424 "Lost clock %" GST_PTR_FORMAT " provided by %" GST_PTR_FORMAT,
3425 bin->provided_clock, bin->clock_provider);
3426 provided_clock_p = &bin->provided_clock;
3427 clock_provider_p = &bin->clock_provider;
3428 gst_object_replace ((GstObject **) provided_clock_p, NULL);
3429 gst_object_replace ((GstObject **) clock_provider_p, NULL);
3431 GST_DEBUG_OBJECT (bin, "provided %d, playing %d, forward %d",
3432 provided, playing, forward);
3433 GST_OBJECT_UNLOCK (bin);
3439 gst_message_unref (message);
3442 case GST_MESSAGE_CLOCK_PROVIDE:
3446 GST_OBJECT_LOCK (bin);
3447 bin->clock_dirty = TRUE;
3448 /* a new clock is available, post to parent but not
3449 * to the application */
3450 forward = GST_OBJECT_PARENT (bin) != NULL;
3451 GST_OBJECT_UNLOCK (bin);
3457 gst_message_unref (message);
3460 case GST_MESSAGE_ASYNC_START:
3464 GST_DEBUG_OBJECT (bin, "ASYNC_START message %p, %s", message,
3465 src ? GST_OBJECT_NAME (src) : "(NULL)");
3467 GST_OBJECT_LOCK (bin);
3468 bin_do_message_forward (bin, message);
3470 /* we ignore the message if we are going to <= READY */
3471 if ((target = GST_STATE_TARGET (bin)) <= GST_STATE_READY)
3472 goto ignore_start_message;
3474 /* takes ownership of the message */
3475 bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
3477 bin_handle_async_start (bin);
3478 GST_OBJECT_UNLOCK (bin);
3481 ignore_start_message:
3483 GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
3484 gst_element_state_get_name (target));
3485 GST_OBJECT_UNLOCK (bin);
3486 gst_message_unref (message);
3490 case GST_MESSAGE_ASYNC_DONE:
3492 GstClockTime running_time;
3495 GST_DEBUG_OBJECT (bin, "ASYNC_DONE message %p, %s", message,
3496 src ? GST_OBJECT_NAME (src) : "(NULL)");
3498 gst_message_parse_async_done (message, &running_time);
3500 GST_OBJECT_LOCK (bin);
3501 bin_do_message_forward (bin, message);
3503 /* ignore messages if we are shutting down */
3504 if ((target = GST_STATE_TARGET (bin)) <= GST_STATE_READY)
3505 goto ignore_done_message;
3507 bin_replace_message (bin, message, GST_MESSAGE_ASYNC_START);
3508 /* if there are no more ASYNC_START messages, everybody posted
3509 * a ASYNC_DONE and we can post one on the bus. When checking, we
3510 * don't care who still has a pending ASYNC_START */
3511 if (!find_message (bin, NULL, GST_MESSAGE_ASYNC_START)) {
3512 /* nothing found, remove all old ASYNC_DONE messages */
3513 bin_remove_messages (bin, NULL, GST_MESSAGE_ASYNC_DONE);
3515 GST_DEBUG_OBJECT (bin, "async elements commited");
3516 /* when we get an async done message when a state change was busy, we
3517 * need to set the pending_done flag so that at the end of the state
3518 * change we can see if we need to verify pending async elements, hence
3519 * the TRUE argument here. */
3520 bin_handle_async_done (bin, GST_STATE_CHANGE_SUCCESS, TRUE,
3523 GST_DEBUG_OBJECT (bin, "there are more async elements pending");
3525 GST_OBJECT_UNLOCK (bin);
3528 ignore_done_message:
3530 GST_DEBUG_OBJECT (bin, "ignoring message, target %s",
3531 gst_element_state_get_name (target));
3532 GST_OBJECT_UNLOCK (bin);
3533 gst_message_unref (message);
3537 case GST_MESSAGE_STRUCTURE_CHANGE:
3541 gst_message_parse_structure_change (message, NULL, NULL, &busy);
3543 GST_OBJECT_LOCK (bin);
3545 /* while the pad is busy, avoid following it when doing state changes.
3546 * Don't update the cookie yet, we will do that after the structure
3547 * change finished and we are ready to inspect the new updated
3549 bin_replace_message (bin, message, GST_MESSAGE_STRUCTURE_CHANGE);
3552 /* a pad link/unlink ended, signal the state change iterator that we
3553 * need to resync by updating the structure_cookie. */
3554 bin_remove_messages (bin, GST_MESSAGE_SRC (message),
3555 GST_MESSAGE_STRUCTURE_CHANGE);
3556 bin->priv->structure_cookie++;
3558 GST_OBJECT_UNLOCK (bin);
3561 gst_message_unref (message);
3572 /* Send all other messages upward */
3573 GST_DEBUG_OBJECT (bin, "posting message upward");
3574 gst_element_post_message (GST_ELEMENT_CAST (bin), message);
3579 /* generic struct passed to all query fold methods */
3588 typedef void (*QueryInitFunction) (GstBin * bin, QueryFold * fold);
3589 typedef void (*QueryDoneFunction) (GstBin * bin, QueryFold * fold);
3591 /* for duration/position we collect all durations/positions and take
3592 * the MAX of all valid results */
3594 bin_query_min_max_init (GstBin * bin, QueryFold * fold)
3602 bin_query_duration_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3604 GstElement *item = g_value_get_object (vitem);
3606 if (gst_element_query (item, fold->query)) {
3609 g_value_set_boolean (ret, TRUE);
3611 gst_query_parse_duration (fold->query, NULL, &duration);
3613 GST_DEBUG_OBJECT (item, "got duration %" G_GINT64_FORMAT, duration);
3615 if (duration == -1) {
3616 /* duration query succeeded, but duration is unknown */
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);
3639 /* FIXME: re-implement duration caching */
3642 GST_OBJECT_LOCK (bin);
3643 bin->messages = g_list_prepend (bin->messages,
3644 gst_message_new_duration (GST_OBJECT_CAST (bin), format, fold->max));
3645 GST_OBJECT_UNLOCK (bin);
3650 bin_query_position_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3652 GstElement *item = g_value_get_object (vitem);
3654 if (gst_element_query (item, fold->query)) {
3657 g_value_set_boolean (ret, TRUE);
3659 gst_query_parse_position (fold->query, NULL, &position);
3661 GST_DEBUG_OBJECT (item, "got position %" G_GINT64_FORMAT, position);
3663 if (position > fold->max)
3664 fold->max = position;
3671 bin_query_position_done (GstBin * bin, QueryFold * fold)
3675 gst_query_parse_position (fold->query, &format, NULL);
3676 /* store max in query result */
3677 gst_query_set_position (fold->query, format, fold->max);
3679 GST_DEBUG_OBJECT (bin, "max position %" G_GINT64_FORMAT, fold->max);
3683 bin_query_latency_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3685 GstElement *item = g_value_get_object (vitem);
3687 if (gst_element_query (item, fold->query)) {
3688 GstClockTime min, max;
3691 gst_query_parse_latency (fold->query, &live, &min, &max);
3693 GST_DEBUG_OBJECT (item,
3694 "got latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
3695 ", live %d", GST_TIME_ARGS (min), GST_TIME_ARGS (max), live);
3697 /* for the combined latency we collect the MAX of all min latencies and
3698 * the MIN of all max latencies */
3700 if (min > fold->min)
3702 if (fold->max == -1)
3704 else if (max < fold->max)
3706 if (fold->live == FALSE)
3710 g_value_set_boolean (ret, FALSE);
3711 GST_DEBUG_OBJECT (item, "failed query");
3718 bin_query_latency_done (GstBin * bin, QueryFold * fold)
3720 /* store max in query result */
3721 gst_query_set_latency (fold->query, fold->live, fold->min, fold->max);
3723 GST_DEBUG_OBJECT (bin,
3724 "latency min %" GST_TIME_FORMAT ", max %" GST_TIME_FORMAT
3725 ", live %d", GST_TIME_ARGS (fold->min), GST_TIME_ARGS (fold->max),
3729 /* generic fold, return first valid result */
3731 bin_query_generic_fold (const GValue * vitem, GValue * ret, QueryFold * fold)
3733 GstElement *item = g_value_get_object (vitem);
3736 if ((res = gst_element_query (item, fold->query))) {
3737 g_value_set_boolean (ret, TRUE);
3738 GST_DEBUG_OBJECT (item, "answered query %p", fold->query);
3741 /* and stop as soon as we have a valid result */
3746 gst_bin_query (GstElement * element, GstQuery * query)
3748 GstBin *bin = GST_BIN_CAST (element);
3750 gboolean res = FALSE;
3751 GstIteratorFoldFunction fold_func;
3752 QueryInitFunction fold_init = NULL;
3753 QueryDoneFunction fold_done = NULL;
3754 QueryFold fold_data;
3757 switch (GST_QUERY_TYPE (query)) {
3758 case GST_QUERY_DURATION:
3760 /* FIXME: implement duration caching in GstBin again */
3765 gst_query_parse_duration (query, &qformat, NULL);
3767 /* find cached duration query */
3768 GST_OBJECT_LOCK (bin);
3769 for (cached = bin->messages; cached; cached = g_list_next (cached)) {
3770 GstMessage *message = (GstMessage *) cached->data;
3772 if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_DURATION &&
3773 GST_MESSAGE_SRC (message) == GST_OBJECT_CAST (bin)) {
3777 gst_message_parse_duration (message, &format, &duration);
3779 /* if cached same format, copy duration in query result */
3780 if (format == qformat) {
3781 GST_DEBUG_OBJECT (bin, "return cached duration %" G_GINT64_FORMAT,
3783 GST_OBJECT_UNLOCK (bin);
3785 gst_query_set_duration (query, qformat, duration);
3791 GST_OBJECT_UNLOCK (bin);
3793 GST_FIXME ("implement duration caching in GstBin again");
3795 /* no cached value found, iterate and collect durations */
3796 fold_func = (GstIteratorFoldFunction) bin_query_duration_fold;
3797 fold_init = bin_query_min_max_init;
3798 fold_done = bin_query_duration_done;
3801 case GST_QUERY_POSITION:
3803 fold_func = (GstIteratorFoldFunction) bin_query_position_fold;
3804 fold_init = bin_query_min_max_init;
3805 fold_done = bin_query_position_done;
3808 case GST_QUERY_LATENCY:
3810 fold_func = (GstIteratorFoldFunction) bin_query_latency_fold;
3811 fold_init = bin_query_min_max_init;
3812 fold_done = bin_query_latency_done;
3817 fold_func = (GstIteratorFoldFunction) bin_query_generic_fold;
3821 fold_data.query = query;
3823 /* set the result of the query to FALSE initially */
3824 g_value_init (&ret, G_TYPE_BOOLEAN);
3825 g_value_set_boolean (&ret, res);
3827 iter = gst_bin_iterate_sinks (bin);
3828 GST_DEBUG_OBJECT (bin, "Sending query %p (type %s) to sink children",
3829 query, GST_QUERY_TYPE_NAME (query));
3832 fold_init (bin, &fold_data);
3835 GstIteratorResult ires;
3837 ires = gst_iterator_fold (iter, fold_func, &ret, &fold_data);
3840 case GST_ITERATOR_RESYNC:
3841 gst_iterator_resync (iter);
3843 fold_init (bin, &fold_data);
3844 g_value_set_boolean (&ret, res);
3846 case GST_ITERATOR_OK:
3847 case GST_ITERATOR_DONE:
3848 res = g_value_get_boolean (&ret);
3849 if (fold_done != NULL && res)
3850 fold_done (bin, &fold_data);
3858 gst_iterator_free (iter);
3860 GST_DEBUG_OBJECT (bin, "query %p result %d", query, res);
3866 compare_name (const GValue * velement, const gchar * name)
3869 GstElement *element = g_value_get_object (velement);
3871 GST_OBJECT_LOCK (element);
3872 eq = strcmp (GST_ELEMENT_NAME (element), name);
3873 GST_OBJECT_UNLOCK (element);
3879 * gst_bin_get_by_name:
3881 * @name: the element name to search for
3883 * Gets the element with the given name from a bin. This
3884 * function recurses into child bins.
3886 * Returns NULL if no element with the given name is found in the bin.
3888 * MT safe. Caller owns returned reference.
3890 * Returns: (transfer full): the #GstElement with the given name, or NULL
3893 gst_bin_get_by_name (GstBin * bin, const gchar * name)
3895 GstIterator *children;
3896 GValue result = { 0, };
3897 GstElement *element;
3900 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
3902 GST_CAT_INFO (GST_CAT_PARENTAGE, "[%s]: looking up child element %s",
3903 GST_ELEMENT_NAME (bin), name);
3905 children = gst_bin_iterate_recurse (bin);
3906 found = gst_iterator_find_custom (children,
3907 (GCompareFunc) compare_name, &result, (gpointer) name);
3908 gst_iterator_free (children);
3911 element = g_value_dup_object (&result);
3912 g_value_unset (&result);
3921 * gst_bin_get_by_name_recurse_up:
3923 * @name: the element name to search for
3925 * Gets the element with the given name from this bin. If the
3926 * element is not found, a recursion is performed on the parent bin.
3929 * - no element with the given name is found in the bin
3931 * MT safe. Caller owns returned reference.
3933 * Returns: (transfer full): the #GstElement with the given name, or NULL
3936 gst_bin_get_by_name_recurse_up (GstBin * bin, const gchar * name)
3940 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
3941 g_return_val_if_fail (name != NULL, NULL);
3943 result = gst_bin_get_by_name (bin, name);
3948 parent = gst_object_get_parent (GST_OBJECT_CAST (bin));
3950 if (GST_IS_BIN (parent)) {
3951 result = gst_bin_get_by_name_recurse_up (GST_BIN_CAST (parent), name);
3953 gst_object_unref (parent);
3961 compare_interface (const GValue * velement, GValue * interface)
3963 GstElement *element = g_value_get_object (velement);
3964 GType interface_type = (GType) g_value_get_pointer (interface);
3967 if (G_TYPE_CHECK_INSTANCE_TYPE (element, interface_type)) {
3976 * gst_bin_get_by_interface:
3978 * @iface: the #GType of an interface
3980 * Looks for an element inside the bin that implements the given
3981 * interface. If such an element is found, it returns the element.
3982 * You can cast this element to the given interface afterwards. If you want
3983 * all elements that implement the interface, use
3984 * gst_bin_iterate_all_by_interface(). This function recurses into child bins.
3986 * MT safe. Caller owns returned reference.
3988 * Returns: (transfer full): A #GstElement inside the bin implementing the interface
3991 gst_bin_get_by_interface (GstBin * bin, GType iface)
3993 GstIterator *children;
3994 GValue result = { 0, };
3995 GstElement *element;
3997 GValue viface = { 0, };
3999 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
4000 g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
4002 g_value_init (&viface, G_TYPE_POINTER);
4003 g_value_set_pointer (&viface, (gpointer) iface);
4005 children = gst_bin_iterate_recurse (bin);
4006 found = gst_iterator_find_custom (children, (GCompareFunc) compare_interface,
4008 gst_iterator_free (children);
4011 element = g_value_dup_object (&result);
4012 g_value_unset (&result);
4016 g_value_unset (&viface);
4022 * gst_bin_iterate_all_by_interface:
4024 * @iface: the #GType of an interface
4026 * Looks for all elements inside the bin that implements the given
4027 * interface. You can safely cast all returned elements to the given interface.
4028 * The function recurses inside child bins. The iterator will yield a series
4029 * of #GstElement that should be unreffed after use.
4031 * Each element yielded by the iterator will have its refcount increased, so
4034 * MT safe. Caller owns returned value.
4036 * Returns: (transfer full): a #GstIterator of #GstElement for all elements
4037 * in the bin implementing the given interface, or NULL
4040 gst_bin_iterate_all_by_interface (GstBin * bin, GType iface)
4042 GstIterator *children;
4043 GstIterator *result;
4044 GValue viface = { 0, };
4046 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
4047 g_return_val_if_fail (G_TYPE_IS_INTERFACE (iface), NULL);
4049 g_value_init (&viface, G_TYPE_POINTER);
4050 g_value_set_pointer (&viface, (gpointer) iface);
4052 children = gst_bin_iterate_recurse (bin);
4053 result = gst_iterator_filter (children, (GCompareFunc) compare_interface,
4056 g_value_unset (&viface);