2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * All elements have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate or
47 * gst_element_get_request_pad() with the template name such as "src_\%d".
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * gst_element_provides_clock() returns %TRUE. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If
72 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock slection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
79 * Last reviewed on 2009-05-29 (0.10.24)
82 #include "gst_private.h"
85 #include <gobject/gvaluecollector.h>
87 #include "gstelement.h"
88 #include "gstelementdetails.h"
89 #include "gstenumtypes.h"
91 #include "gstmarshal.h"
97 #include "gst-i18n-lib.h"
99 /* Element signals and args */
115 #ifdef GST_DISABLE_DEPRECATED
116 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
117 #include <libxml/parser.h>
118 xmlNodePtr gst_object_save_thyself (const GstObject * object,
120 GstObject *gst_object_load_thyself (xmlNodePtr parent);
121 void gst_pad_load_and_link (xmlNodePtr self, GstObject * parent);
125 static void gst_element_class_init (GstElementClass * klass);
126 static void gst_element_init (GstElement * element);
127 static void gst_element_base_class_init (gpointer g_class);
128 static void gst_element_base_class_finalize (gpointer g_class);
130 static void gst_element_dispose (GObject * object);
131 static void gst_element_finalize (GObject * object);
133 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
134 GstStateChange transition);
135 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
136 GstState * state, GstState * pending, GstClockTime timeout);
137 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
139 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
141 static gboolean gst_element_default_send_event (GstElement * element,
143 static gboolean gst_element_default_query (GstElement * element,
146 static GstPadTemplate
147 * gst_element_class_get_request_pad_template (GstElementClass *
148 element_class, const gchar * name);
150 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
151 static xmlNodePtr gst_element_save_thyself (GstObject * object,
153 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
156 static GstObjectClass *parent_class = NULL;
157 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
159 /* this is used in gstelementfactory.c:gst_element_register() */
160 GQuark _gst_elementclass_factory = 0;
163 gst_element_get_type (void)
165 static volatile gsize gst_element_type = 0;
167 if (g_once_init_enter (&gst_element_type)) {
169 static const GTypeInfo element_info = {
170 sizeof (GstElementClass),
171 gst_element_base_class_init,
172 gst_element_base_class_finalize,
173 (GClassInitFunc) gst_element_class_init,
178 (GInstanceInitFunc) gst_element_init,
182 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
183 &element_info, G_TYPE_FLAG_ABSTRACT);
185 _gst_elementclass_factory =
186 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
187 g_once_init_leave (&gst_element_type, _type);
189 return gst_element_type;
193 gst_element_class_init (GstElementClass * klass)
195 GObjectClass *gobject_class;
196 GstObjectClass *gstobject_class;
198 gobject_class = (GObjectClass *) klass;
199 gstobject_class = (GstObjectClass *) klass;
201 parent_class = g_type_class_peek_parent (klass);
204 * GstElement::pad-added:
205 * @gstelement: the object which received the signal
206 * @new_pad: the pad that has been added
208 * a new #GstPad has been added to the element. Note that this signal will
209 * usually be emitted from the context of the streaming thread. Also keep in
210 * mind that if you add new elements to the pipeline in the signal handler
211 * you will need to set them to the desired target state with
212 * gst_element_set_state() or gst_element_sync_state_with_parent().
214 gst_element_signals[PAD_ADDED] =
215 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
216 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
217 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
219 * GstElement::pad-removed:
220 * @gstelement: the object which received the signal
221 * @old_pad: the pad that has been removed
223 * a #GstPad has been removed from the element
225 gst_element_signals[PAD_REMOVED] =
226 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
227 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
228 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
230 * GstElement::no-more-pads:
231 * @gstelement: the object which received the signal
233 * This signals that the element will not generate more dynamic pads.
234 * Note that this signal will usually be emitted from the context of
235 * the streaming thread.
237 gst_element_signals[NO_MORE_PADS] =
238 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
239 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
240 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
242 gobject_class->dispose = gst_element_dispose;
243 gobject_class->finalize = gst_element_finalize;
245 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
246 gstobject_class->save_thyself =
247 ((gpointer (*)(GstObject * object,
248 gpointer self)) * GST_DEBUG_FUNCPTR (gst_element_save_thyself));
249 gstobject_class->restore_thyself =
250 ((void (*)(GstObject * object,
251 gpointer self)) *GST_DEBUG_FUNCPTR (gst_element_restore_thyself));
254 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
255 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
256 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
257 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
258 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
259 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
260 klass->numpadtemplates = 0;
262 klass->elementfactory = NULL;
266 gst_element_base_class_init (gpointer g_class)
268 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
270 /* FIXME 0.11: Copy the element details and instead of clearing the
271 * pad template list copy the list and increase the refcount of
272 * the pad templates by one.
274 * This will make it possible to add pad templates and set element
275 * details in the class_init functions and is the real GObject way
277 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
279 memset (&element_class->details, 0, sizeof (GstElementDetails));
280 element_class->meta_data = NULL;
281 element_class->padtemplates = NULL;
283 /* set the factory, see gst_element_register() */
284 element_class->elementfactory =
285 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
286 _gst_elementclass_factory);
287 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
288 element_class->elementfactory);
292 gst_element_base_class_finalize (gpointer g_class)
294 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
296 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
297 g_list_free (klass->padtemplates);
298 __gst_element_details_clear (&klass->details);
299 if (klass->meta_data) {
300 gst_structure_free (klass->meta_data);
301 klass->meta_data = NULL;
306 gst_element_init (GstElement * element)
308 GST_STATE (element) = GST_STATE_NULL;
309 GST_STATE_TARGET (element) = GST_STATE_NULL;
310 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
311 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
312 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
314 /* FIXME 0.11: Store this directly in the instance struct */
315 element->state_lock = g_slice_new (GStaticRecMutex);
316 g_static_rec_mutex_init (element->state_lock);
317 element->state_cond = g_cond_new ();
321 * gst_element_release_request_pad:
322 * @element: a #GstElement to release the request pad of.
323 * @pad: the #GstPad to release.
325 * Makes the element free the previously requested pad as obtained
326 * with gst_element_get_request_pad().
328 * This does not unref the pad. If the pad was created by using
329 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
330 * followed by gst_object_unref() to free the @pad.
335 gst_element_release_request_pad (GstElement * element, GstPad * pad)
337 GstElementClass *oclass;
339 g_return_if_fail (GST_IS_ELEMENT (element));
340 g_return_if_fail (GST_IS_PAD (pad));
342 oclass = GST_ELEMENT_GET_CLASS (element);
344 /* if the element implements a custom release function we call that, else we
345 * simply remove the pad from the element */
346 if (oclass->release_pad)
347 (oclass->release_pad) (element, pad);
349 gst_element_remove_pad (element, pad);
353 * gst_element_requires_clock:
354 * @element: a #GstElement to query
356 * Query if the element requires a clock.
358 * Returns: %TRUE if the element requires a clock
363 gst_element_requires_clock (GstElement * element)
367 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
369 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
375 * gst_element_provides_clock:
376 * @element: a #GstElement to query
378 * Query if the element provides a clock. A #GstClock provided by an
379 * element can be used as the global #GstClock for the pipeline.
380 * An element that can provide a clock is only required to do so in the PAUSED
381 * state, this means when it is fully negotiated and has allocated the resources
382 * to operate the clock.
384 * Returns: %TRUE if the element provides a clock
389 gst_element_provides_clock (GstElement * element)
393 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
395 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
401 * gst_element_provide_clock:
402 * @element: a #GstElement to query
404 * Get the clock provided by the given element.
405 * <note>An element is only required to provide a clock in the PAUSED
406 * state. Some elements can provide a clock in other states.</note>
408 * Returns: (transfer full): the GstClock provided by the element or %NULL
409 * if no clock could be provided. Unref after usage.
414 gst_element_provide_clock (GstElement * element)
416 GstClock *result = NULL;
417 GstElementClass *oclass;
419 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
421 oclass = GST_ELEMENT_GET_CLASS (element);
423 if (oclass->provide_clock)
424 result = oclass->provide_clock (element);
430 * gst_element_set_clock:
431 * @element: a #GstElement to set the clock for.
432 * @clock: the #GstClock to set for the element.
434 * Sets the clock for the element. This function increases the
435 * refcount on the clock. Any previously set clock on the object
438 * Returns: %TRUE if the element accepted the clock. An element can refuse a
439 * clock when it, for example, is not able to slave its internal clock to the
440 * @clock or when it requires a specific clock to operate.
445 gst_element_set_clock (GstElement * element, GstClock * clock)
447 GstElementClass *oclass;
451 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
452 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
454 oclass = GST_ELEMENT_GET_CLASS (element);
456 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
458 if (oclass->set_clock)
459 res = oclass->set_clock (element, clock);
462 /* only update the clock pointer if the element accepted the clock */
463 GST_OBJECT_LOCK (element);
464 clock_p = &element->clock;
465 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
466 GST_OBJECT_UNLOCK (element);
472 * gst_element_get_clock:
473 * @element: a #GstElement to get the clock of.
475 * Gets the currently configured clock of the element. This is the clock as was
476 * last set with gst_element_set_clock().
478 * Returns: (transfer full): the #GstClock of the element. unref after usage.
483 gst_element_get_clock (GstElement * element)
487 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
489 GST_OBJECT_LOCK (element);
490 if ((result = element->clock))
491 gst_object_ref (result);
492 GST_OBJECT_UNLOCK (element);
498 * gst_element_set_base_time:
499 * @element: a #GstElement.
500 * @time: the base time to set.
502 * Set the base time of an element. See gst_element_get_base_time().
507 gst_element_set_base_time (GstElement * element, GstClockTime time)
511 g_return_if_fail (GST_IS_ELEMENT (element));
513 GST_OBJECT_LOCK (element);
514 old = element->base_time;
515 element->base_time = time;
516 GST_OBJECT_UNLOCK (element);
518 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
519 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
520 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
524 * gst_element_get_base_time:
525 * @element: a #GstElement.
527 * Returns the base time of the element. The base time is the
528 * absolute time of the clock when this element was last put to
529 * PLAYING. Subtracting the base time from the clock time gives
530 * the running time of the element.
532 * Returns: the base time of the element.
537 gst_element_get_base_time (GstElement * element)
541 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
543 GST_OBJECT_LOCK (element);
544 result = element->base_time;
545 GST_OBJECT_UNLOCK (element);
551 * gst_element_set_start_time:
552 * @element: a #GstElement.
553 * @time: the base time to set.
555 * Set the start time of an element. The start time of the element is the
556 * running time of the element when it last went to the PAUSED state. In READY
557 * or after a flushing seek, it is set to 0.
559 * Toplevel elements like #GstPipeline will manage the start_time and
560 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
561 * on such a toplevel element will disable the distribution of the base_time to
562 * the children and can be useful if the application manages the base_time
563 * itself, for example if you want to synchronize capture from multiple
564 * pipelines, and you can also ensure that the pipelines have the same clock.
571 gst_element_set_start_time (GstElement * element, GstClockTime time)
575 g_return_if_fail (GST_IS_ELEMENT (element));
577 GST_OBJECT_LOCK (element);
578 old = GST_ELEMENT_START_TIME (element);
579 GST_ELEMENT_START_TIME (element) = time;
580 GST_OBJECT_UNLOCK (element);
582 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
583 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
584 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
588 * gst_element_get_start_time:
589 * @element: a #GstElement.
591 * Returns the start time of the element. The start time is the
592 * running time of the clock when this element was last put to PAUSED.
594 * Usually the start_time is managed by a toplevel element such as
599 * Returns: the start time of the element.
604 gst_element_get_start_time (GstElement * element)
608 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
610 GST_OBJECT_LOCK (element);
611 result = GST_ELEMENT_START_TIME (element);
612 GST_OBJECT_UNLOCK (element);
618 * gst_element_is_indexable:
619 * @element: a #GstElement.
621 * Queries if the element can be indexed.
623 * Returns: TRUE if the element can be indexed.
628 gst_element_is_indexable (GstElement * element)
632 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
634 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
640 * gst_element_set_index:
641 * @element: a #GstElement.
642 * @index: (transfer none): a #GstIndex.
644 * Set @index on the element. The refcount of the index
645 * will be increased, any previously set index is unreffed.
650 gst_element_set_index (GstElement * element, GstIndex * index)
652 GstElementClass *oclass;
654 g_return_if_fail (GST_IS_ELEMENT (element));
655 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
657 oclass = GST_ELEMENT_GET_CLASS (element);
659 if (oclass->set_index)
660 oclass->set_index (element, index);
664 * gst_element_get_index:
665 * @element: a #GstElement.
667 * Gets the index from the element.
669 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
670 * element. unref after usage.
675 gst_element_get_index (GstElement * element)
677 GstElementClass *oclass;
678 GstIndex *result = NULL;
680 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
682 oclass = GST_ELEMENT_GET_CLASS (element);
684 if (oclass->get_index)
685 result = oclass->get_index (element);
691 * gst_element_add_pad:
692 * @element: a #GstElement to add the pad to.
693 * @pad: (transfer full): the #GstPad to add to the element.
695 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
696 * see gst_object_set_parent() for refcounting information.
698 * Pads are not automatically activated so elements should perform the needed
699 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
700 * state. See gst_pad_set_active() for more information about activating pads.
702 * The pad and the element should be unlocked when calling this function.
704 * This function will emit the #GstElement::pad-added signal on the element.
706 * Returns: %TRUE if the pad could be added. This function can fail when
707 * a pad with the same name already existed or the pad already had another
713 gst_element_add_pad (GstElement * element, GstPad * pad)
718 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
719 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
721 /* locking pad to look at the name */
722 GST_OBJECT_LOCK (pad);
723 pad_name = g_strdup (GST_PAD_NAME (pad));
724 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
725 GST_STR_NULL (pad_name));
726 flushing = GST_PAD_IS_FLUSHING (pad);
727 GST_OBJECT_UNLOCK (pad);
729 /* then check to see if there's already a pad by that name here */
730 GST_OBJECT_LOCK (element);
731 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
734 /* try to set the pad's parent */
735 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
736 GST_OBJECT_CAST (element))))
739 /* check for flushing pads */
740 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
741 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
742 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
743 "use gst_pad_set_active(pad,TRUE) before adding it.",
744 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
746 GST_OBJECT_LOCK (pad);
747 GST_PAD_UNSET_FLUSHING (pad);
748 GST_OBJECT_UNLOCK (pad);
753 /* add it to the list */
754 switch (gst_pad_get_direction (pad)) {
756 element->srcpads = g_list_prepend (element->srcpads, pad);
757 element->numsrcpads++;
760 element->sinkpads = g_list_prepend (element->sinkpads, pad);
761 element->numsinkpads++;
766 element->pads = g_list_prepend (element->pads, pad);
768 element->pads_cookie++;
769 GST_OBJECT_UNLOCK (element);
771 /* emit the PAD_ADDED signal */
772 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
779 g_critical ("Padname %s is not unique in element %s, not adding",
780 pad_name, GST_ELEMENT_NAME (element));
781 GST_OBJECT_UNLOCK (element);
788 ("Pad %s already has parent when trying to add to element %s",
789 pad_name, GST_ELEMENT_NAME (element));
790 GST_OBJECT_UNLOCK (element);
796 GST_OBJECT_LOCK (pad);
798 ("Trying to add pad %s to element %s, but it has no direction",
799 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
800 GST_OBJECT_UNLOCK (pad);
801 GST_OBJECT_UNLOCK (element);
807 * gst_element_remove_pad:
808 * @element: a #GstElement to remove pad from.
809 * @pad: (transfer none): the #GstPad to remove from the element.
811 * Removes @pad from @element. @pad will be destroyed if it has not been
812 * referenced elsewhere using gst_object_unparent().
814 * This function is used by plugin developers and should not be used
815 * by applications. Pads that were dynamically requested from elements
816 * with gst_element_get_request_pad() should be released with the
817 * gst_element_release_request_pad() function instead.
819 * Pads are not automatically deactivated so elements should perform the needed
820 * steps to deactivate the pad in case this pad is removed in the PAUSED or
821 * PLAYING state. See gst_pad_set_active() for more information about
824 * The pad and the element should be unlocked when calling this function.
826 * This function will emit the #GstElement::pad-removed signal on the element.
828 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
829 * pad does not belong to the provided element.
834 gst_element_remove_pad (GstElement * element, GstPad * pad)
838 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
839 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
841 /* locking pad to look at the name and parent */
842 GST_OBJECT_LOCK (pad);
843 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
844 GST_STR_NULL (GST_PAD_NAME (pad)));
846 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
848 GST_OBJECT_UNLOCK (pad);
851 if ((peer = gst_pad_get_peer (pad))) {
852 /* window for MT unsafeness, someone else could unlink here
853 * and then we call unlink with wrong pads. The unlink
854 * function would catch this and safely return failed. */
855 if (GST_PAD_IS_SRC (pad))
856 gst_pad_unlink (pad, peer);
858 gst_pad_unlink (peer, pad);
860 gst_object_unref (peer);
863 GST_OBJECT_LOCK (element);
864 /* remove it from the list */
865 switch (gst_pad_get_direction (pad)) {
867 element->srcpads = g_list_remove (element->srcpads, pad);
868 element->numsrcpads--;
871 element->sinkpads = g_list_remove (element->sinkpads, pad);
872 element->numsinkpads--;
875 g_critical ("Removing pad without direction???");
878 element->pads = g_list_remove (element->pads, pad);
880 element->pads_cookie++;
881 GST_OBJECT_UNLOCK (element);
883 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
884 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
886 gst_object_unparent (GST_OBJECT_CAST (pad));
893 /* FIXME, locking order? */
894 GST_OBJECT_LOCK (element);
895 g_critical ("Padname %s:%s does not belong to element %s when removing",
896 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
897 GST_OBJECT_UNLOCK (element);
898 GST_OBJECT_UNLOCK (pad);
904 * gst_element_no_more_pads:
905 * @element: a #GstElement
907 * Use this function to signal that the element does not expect any more pads
908 * to show up in the current pipeline. This function should be called whenever
909 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
910 * pad templates use this in combination with autopluggers to figure out that
911 * the element is done initializing its pads.
913 * This function emits the #GstElement::no-more-pads signal.
918 gst_element_no_more_pads (GstElement * element)
920 g_return_if_fail (GST_IS_ELEMENT (element));
922 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
926 pad_compare_name (GstPad * pad1, const gchar * name)
930 GST_OBJECT_LOCK (pad1);
931 result = strcmp (GST_PAD_NAME (pad1), name);
932 GST_OBJECT_UNLOCK (pad1);
938 * gst_element_get_static_pad:
939 * @element: a #GstElement to find a static pad of.
940 * @name: the name of the static #GstPad to retrieve.
942 * Retrieves a pad from @element by name. This version only retrieves
943 * already-existing (i.e. 'static') pads.
945 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
951 gst_element_get_static_pad (GstElement * element, const gchar * name)
954 GstPad *result = NULL;
956 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
957 g_return_val_if_fail (name != NULL, NULL);
959 GST_OBJECT_LOCK (element);
961 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
963 result = GST_PAD_CAST (find->data);
964 gst_object_ref (result);
967 if (result == NULL) {
968 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
969 name, GST_ELEMENT_NAME (element));
971 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
972 GST_ELEMENT_NAME (element), name);
974 GST_OBJECT_UNLOCK (element);
980 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
981 const gchar * name, const GstCaps * caps)
983 GstPad *newpad = NULL;
984 GstElementClass *oclass;
986 oclass = GST_ELEMENT_GET_CLASS (element);
988 #ifndef G_DISABLE_CHECKS
989 /* Some sanity checking here */
993 /* Is this the template name? */
994 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
995 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
997 const gchar *str, *data;
1000 /* Otherwise check if it's a valid name for the name template */
1001 str = strchr (templ->name_template, '%');
1002 g_return_val_if_fail (str != NULL, NULL);
1003 g_return_val_if_fail (strncmp (templ->name_template, name,
1004 str - templ->name_template) == 0, NULL);
1005 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
1007 data = name + (str - templ->name_template);
1009 /* Can either be %s or %d or %u, do sanity checking for %d */
1010 if (*(str + 1) == 'd') {
1014 tmp = g_ascii_strtoll (data, &endptr, 10);
1015 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
1016 && *endptr == '\0', NULL);
1017 } else if (*(str + 1) == 'u') {
1021 tmp = g_ascii_strtoull (data, &endptr, 10);
1022 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
1026 pad = gst_element_get_static_pad (element, name);
1028 gst_object_unref (pad);
1029 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1030 g_critical ("Element %s already has a pad named %s, the behaviour of "
1031 " gst_element_get_request_pad() for existing pads is undefined!",
1032 GST_ELEMENT_NAME (element), name);
1037 if (oclass->request_new_pad_full)
1038 newpad = (oclass->request_new_pad_full) (element, templ, name, caps);
1039 else if (oclass->request_new_pad)
1040 newpad = (oclass->request_new_pad) (element, templ, name);
1043 gst_object_ref (newpad);
1049 * gst_element_get_request_pad:
1050 * @element: a #GstElement to find a request pad of.
1051 * @name: the name of the request #GstPad to retrieve.
1053 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1054 * retrieves request pads. The pad should be released with
1055 * gst_element_release_request_pad().
1057 * This method is slow and will be deprecated in the future. New code should
1058 * use gst_element_request_pad() with the requested template.
1060 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1061 * Release after usage.
1064 gst_element_get_request_pad (GstElement * element, const gchar * name)
1066 GstPadTemplate *templ = NULL;
1068 const gchar *req_name = NULL;
1069 gboolean templ_found = FALSE;
1072 gchar *str, *endptr = NULL;
1073 GstElementClass *class;
1075 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1076 g_return_val_if_fail (name != NULL, NULL);
1078 class = GST_ELEMENT_GET_CLASS (element);
1080 /* if the name contains a %, we assume it's the complete template name. Get
1081 * the template and try to get a pad */
1082 if (strstr (name, "%")) {
1083 templ = gst_element_class_get_request_pad_template (class, name);
1088 /* there is no % in the name, try to find a matching template */
1089 list = class->padtemplates;
1090 while (!templ_found && list) {
1091 templ = (GstPadTemplate *) list->data;
1092 if (templ->presence == GST_PAD_REQUEST) {
1093 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1094 templ->name_template);
1095 /* see if we find an exact match */
1096 if (strcmp (name, templ->name_template) == 0) {
1101 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1102 and %d and %u, occurring at the end of the name_template, are the only
1104 else if ((str = strchr (templ->name_template, '%'))
1105 && strncmp (templ->name_template, name,
1106 str - templ->name_template) == 0
1107 && strlen (name) > str - templ->name_template) {
1108 data = name + (str - templ->name_template);
1109 if (*(str + 1) == 'd') {
1113 tmp = strtol (data, &endptr, 10);
1114 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1120 } else if (*(str + 1) == 'u') {
1124 tmp = strtoul (data, &endptr, 10);
1125 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1145 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1151 * gst_element_request_pad:
1152 * @element: a #GstElement to find a request pad of.
1153 * @templ: a #GstPadTemplate of which we want a pad of.
1154 * @name: (transfer none) (allow-none): the name of the request #GstPad
1155 * to retrieve. Can be %NULL.
1156 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1157 * request. Can be %NULL.
1159 * Retrieves a request pad from the element according to the provided template.
1160 * Pad templates can be looked up using
1161 * gst_element_factory_get_static_pad_templates().
1163 * If the @caps are specified and the element implements thew new
1164 * request_new_pad_full virtual method, the element will use them to select
1165 * which pad to create.
1167 * The pad should be released with gst_element_release_request_pad().
1169 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1170 * Release after usage.
1175 gst_element_request_pad (GstElement * element,
1176 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1178 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1179 g_return_val_if_fail (templ != NULL, NULL);
1181 return _gst_element_request_pad (element, templ, name, caps);
1185 * gst_element_get_pad:
1186 * @element: a #GstElement.
1187 * @name: the name of the pad to retrieve.
1189 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1190 * first, then gst_element_get_request_pad().
1192 * Deprecated: This function is deprecated as it's unclear if the reference
1193 * to the result pad should be released with gst_object_unref() in case of a static pad
1194 * or gst_element_release_request_pad() in case of a request pad.
1195 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1197 * Returns: (transfer full): the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1198 * depending on the type of the pad.
1200 #ifndef GST_REMOVE_DEPRECATED
1201 #ifdef GST_DISABLE_DEPRECATED
1202 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1205 gst_element_get_pad (GstElement * element, const gchar * name)
1209 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1210 g_return_val_if_fail (name != NULL, NULL);
1212 pad = gst_element_get_static_pad (element, name);
1214 pad = gst_element_get_request_pad (element, name);
1218 #endif /* GST_REMOVE_DEPRECATED */
1220 static GstIteratorItem
1221 iterate_pad (GstIterator * it, GstPad * pad)
1223 gst_object_ref (pad);
1224 return GST_ITERATOR_ITEM_PASS;
1227 static GstIterator *
1228 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1230 GstIterator *result;
1232 GST_OBJECT_LOCK (element);
1233 gst_object_ref (element);
1234 result = gst_iterator_new_list (GST_TYPE_PAD,
1235 GST_OBJECT_GET_LOCK (element),
1236 &element->pads_cookie,
1239 (GstIteratorItemFunction) iterate_pad,
1240 (GstIteratorDisposeFunction) gst_object_unref);
1241 GST_OBJECT_UNLOCK (element);
1247 * gst_element_iterate_pads:
1248 * @element: a #GstElement to iterate pads of.
1250 * Retrieves an iterator of @element's pads. The iterator should
1251 * be freed after usage. Also more specialized iterators exists such as
1252 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1254 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1260 gst_element_iterate_pads (GstElement * element)
1262 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1264 return gst_element_iterate_pad_list (element, &element->pads);
1268 * gst_element_iterate_src_pads:
1269 * @element: a #GstElement.
1271 * Retrieves an iterator of @element's source pads.
1273 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1279 gst_element_iterate_src_pads (GstElement * element)
1281 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1283 return gst_element_iterate_pad_list (element, &element->srcpads);
1287 * gst_element_iterate_sink_pads:
1288 * @element: a #GstElement.
1290 * Retrieves an iterator of @element's sink pads.
1292 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1298 gst_element_iterate_sink_pads (GstElement * element)
1300 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1302 return gst_element_iterate_pad_list (element, &element->sinkpads);
1306 * gst_element_class_add_pad_template:
1307 * @klass: the #GstElementClass to add the pad template to.
1308 * @templ: (transfer none): a #GstPadTemplate to add to the element class.
1310 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1311 * functions of classes.
1314 gst_element_class_add_pad_template (GstElementClass * klass,
1315 GstPadTemplate * templ)
1317 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1318 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1320 /* FIXME 0.11: allow replacing the pad templates by
1321 * calling this with the same name as an already existing pad
1322 * template. For this we _must_ _not_ ref the added pad template
1323 * a second time and _must_ document that this function takes
1324 * ownership of the pad template. Otherwise we will leak pad templates
1325 * or the caller unref's the pad template and it disappears */
1326 /* avoid registering pad templates with the same name */
1327 g_return_if_fail (gst_element_class_get_pad_template (klass,
1328 templ->name_template) == NULL);
1330 klass->padtemplates = g_list_append (klass->padtemplates,
1331 gst_object_ref (templ));
1332 klass->numpadtemplates++;
1336 gst_element_class_add_meta_data (GstElementClass * klass,
1337 const gchar * key, const gchar * value)
1339 if (!klass->meta_data) {
1340 /* FIXME: use a quark for "metadata" */
1341 klass->meta_data = gst_structure_empty_new ("metadata");
1344 gst_structure_set ((GstStructure *) klass->meta_data,
1345 key, G_TYPE_STRING, value, NULL);
1349 * gst_element_class_set_documentation_uri:
1350 * @klass: class to set details for
1351 * @uri: uri of element documentation
1353 * Set uri pointing to user documentation. Applications can use this to show
1354 * help for e.g. effects to users.
1359 gst_element_class_set_documentation_uri (GstElementClass * klass,
1362 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1364 gst_element_class_add_meta_data (klass, "doc-uri", uri);
1368 * gst_element_class_set_icon_name:
1369 * @klass: class to set details for
1370 * @name: name of an icon
1372 * Elements that bridge to certain other products can include an icon of that
1373 * used product. Application can show the icon in menus/selectors to help
1374 * identifying specific elements.
1379 gst_element_class_set_icon_name (GstElementClass * klass, const gchar * name)
1381 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1383 gst_element_class_add_meta_data (klass, "icon-name", name);
1386 /* FIXME-0.11: deprecate and remove gst_element_class_set_details*() */
1388 * gst_element_class_set_details:
1389 * @klass: class to set details for
1390 * @details: details to set
1392 * Sets the detailed information for a #GstElementClass.
1393 * <note>This function is for use in _base_init functions only.</note>
1395 * The @details are copied.
1397 * Deprecated: Use gst_element_class_set_details_simple() instead.
1399 #ifndef GST_REMOVE_DEPRECATED
1400 #ifdef GST_DISABLE_DEPRECATED
1401 void gst_element_class_set_details (GstElementClass * klass,
1402 const GstElementDetails * details);
1405 gst_element_class_set_details (GstElementClass * klass,
1406 const GstElementDetails * details)
1408 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1409 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1411 __gst_element_details_copy (&klass->details, details);
1416 * gst_element_class_set_details_simple:
1417 * @klass: class to set details for
1418 * @longname: The long English name of the element. E.g. "File Sink"
1419 * @classification: String describing the type of element, as an unordered list
1420 * separated with slashes ('/'). See draft-klass.txt of the design docs
1421 * for more details and common types. E.g: "Sink/File"
1422 * @description: Sentence describing the purpose of the element.
1423 * E.g: "Write stream to a file"
1424 * @author: Name and contact details of the author(s). Use \n to separate
1425 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1427 * Sets the detailed information for a #GstElementClass. Simpler version of
1428 * gst_element_class_set_details() that generates less linker overhead.
1429 * <note>This function is for use in _base_init functions only.</note>
1431 * The detail parameter strings are copied into the #GstElementDetails for
1432 * the element class.
1437 gst_element_class_set_details_simple (GstElementClass * klass,
1438 const gchar * longname, const gchar * classification,
1439 const gchar * description, const gchar * author)
1441 const GstElementDetails details =
1442 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1443 (gchar *) description, (gchar *) author);
1445 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1447 __gst_element_details_copy (&klass->details, &details);
1451 * gst_element_class_get_pad_template_list:
1452 * @element_class: a #GstElementClass to get pad templates of.
1454 * Retrieves a list of the pad templates associated with @element_class. The
1455 * list must not be modified by the calling code.
1456 * <note>If you use this function in the #GInstanceInitFunc of an object class
1457 * that has subclasses, make sure to pass the g_class parameter of the
1458 * #GInstanceInitFunc here.</note>
1460 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1464 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1466 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1468 return element_class->padtemplates;
1472 * gst_element_class_get_pad_template:
1473 * @element_class: a #GstElementClass to get the pad template of.
1474 * @name: the name of the #GstPadTemplate to get.
1476 * Retrieves a padtemplate from @element_class with the given name.
1477 * <note>If you use this function in the #GInstanceInitFunc of an object class
1478 * that has subclasses, make sure to pass the g_class parameter of the
1479 * #GInstanceInitFunc here.</note>
1481 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1482 * if none was found. No unreferencing is necessary.
1485 gst_element_class_get_pad_template (GstElementClass *
1486 element_class, const gchar * name)
1490 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1491 g_return_val_if_fail (name != NULL, NULL);
1493 padlist = element_class->padtemplates;
1496 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1498 if (strcmp (padtempl->name_template, name) == 0)
1501 padlist = g_list_next (padlist);
1507 static GstPadTemplate *
1508 gst_element_class_get_request_pad_template (GstElementClass *
1509 element_class, const gchar * name)
1511 GstPadTemplate *tmpl;
1513 tmpl = gst_element_class_get_pad_template (element_class, name);
1514 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1520 /* get a random pad on element of the given direction.
1521 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1524 gst_element_get_random_pad (GstElement * element,
1525 gboolean need_linked, GstPadDirection dir)
1527 GstPad *result = NULL;
1530 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1534 GST_OBJECT_LOCK (element);
1535 pads = element->srcpads;
1538 GST_OBJECT_LOCK (element);
1539 pads = element->sinkpads;
1542 goto wrong_direction;
1544 for (; pads; pads = g_list_next (pads)) {
1545 GstPad *pad = GST_PAD_CAST (pads->data);
1547 GST_OBJECT_LOCK (pad);
1548 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1549 GST_DEBUG_PAD_NAME (pad));
1551 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1552 /* if we require a linked pad, and it is not linked, continue the
1554 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1555 GST_DEBUG_PAD_NAME (pad));
1556 GST_OBJECT_UNLOCK (pad);
1559 /* found a pad, stop search */
1560 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1561 GST_DEBUG_PAD_NAME (pad));
1562 GST_OBJECT_UNLOCK (pad);
1568 gst_object_ref (result);
1570 GST_OBJECT_UNLOCK (element);
1574 /* ERROR handling */
1577 g_warning ("unknown pad direction %d", dir);
1583 gst_element_default_send_event (GstElement * element, GstEvent * event)
1585 gboolean result = FALSE;
1588 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1589 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1590 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1593 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1594 "pushing %s event to random %s pad %s:%s",
1595 GST_EVENT_TYPE_NAME (event),
1596 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1597 GST_DEBUG_PAD_NAME (pad));
1599 result = gst_pad_push_event (pad, event);
1600 gst_object_unref (pad);
1602 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1603 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1604 gst_event_unref (event);
1610 * gst_element_send_event:
1611 * @element: a #GstElement to send the event to.
1612 * @event: (transfer full): the #GstEvent to send to the element.
1614 * Sends an event to an element. If the element doesn't implement an
1615 * event handler, the event will be pushed on a random linked sink pad for
1616 * upstream events or a random linked source pad for downstream events.
1618 * This function takes owership of the provided event so you should
1619 * gst_event_ref() it if you want to reuse the event after this call.
1621 * Returns: %TRUE if the event was handled.
1626 gst_element_send_event (GstElement * element, GstEvent * event)
1628 GstElementClass *oclass;
1629 gboolean result = FALSE;
1631 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1632 g_return_val_if_fail (event != NULL, FALSE);
1634 oclass = GST_ELEMENT_GET_CLASS (element);
1636 GST_STATE_LOCK (element);
1637 if (oclass->send_event) {
1638 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1639 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1640 result = oclass->send_event (element, event);
1642 result = gst_element_default_send_event (element, event);
1644 GST_STATE_UNLOCK (element);
1651 * @element: a #GstElement to send the event to.
1652 * @rate: The new playback rate
1653 * @format: The format of the seek values
1654 * @flags: The optional seek flags.
1655 * @cur_type: The type and flags for the new current position
1656 * @cur: The value of the new current position
1657 * @stop_type: The type and flags for the new stop position
1658 * @stop: The value of the new stop position
1660 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1661 * the parameters. The seek event is sent to the element using
1662 * gst_element_send_event().
1664 * Returns: %TRUE if the event was handled.
1669 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1670 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1671 GstSeekType stop_type, gint64 stop)
1676 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1679 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1680 result = gst_element_send_event (element, event);
1686 * gst_element_get_query_types:
1687 * @element: a #GstElement to query
1689 * Get an array of query types from the element.
1690 * If the element doesn't implement a query types function,
1691 * the query will be forwarded to the peer of a random linked sink pad.
1693 * Returns: An array of #GstQueryType elements that should not
1694 * be freed or modified.
1698 const GstQueryType *
1699 gst_element_get_query_types (GstElement * element)
1701 GstElementClass *oclass;
1702 const GstQueryType *result = NULL;
1704 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1706 oclass = GST_ELEMENT_GET_CLASS (element);
1708 if (oclass->get_query_types) {
1709 result = oclass->get_query_types (element);
1711 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1714 GstPad *peer = gst_pad_get_peer (pad);
1717 result = gst_pad_get_query_types (peer);
1719 gst_object_unref (peer);
1721 gst_object_unref (pad);
1728 gst_element_default_query (GstElement * element, GstQuery * query)
1730 gboolean result = FALSE;
1733 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1735 result = gst_pad_query (pad, query);
1737 gst_object_unref (pad);
1739 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1741 GstPad *peer = gst_pad_get_peer (pad);
1744 result = gst_pad_query (peer, query);
1746 gst_object_unref (peer);
1748 gst_object_unref (pad);
1755 * gst_element_query:
1756 * @element: a #GstElement to perform the query on.
1757 * @query: (transfer none): the #GstQuery.
1759 * Performs a query on the given element.
1761 * For elements that don't implement a query handler, this function
1762 * forwards the query to a random srcpad or to the peer of a
1763 * random linked sinkpad of this element.
1765 * Please note that some queries might need a running pipeline to work.
1767 * Returns: TRUE if the query could be performed.
1772 gst_element_query (GstElement * element, GstQuery * query)
1774 GstElementClass *oclass;
1775 gboolean result = FALSE;
1777 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1778 g_return_val_if_fail (query != NULL, FALSE);
1780 oclass = GST_ELEMENT_GET_CLASS (element);
1782 if (oclass->query) {
1783 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1784 GST_ELEMENT_NAME (element));
1785 result = oclass->query (element, query);
1787 result = gst_element_default_query (element, query);
1793 * gst_element_post_message:
1794 * @element: a #GstElement posting the message
1795 * @message: (transfer full): a #GstMessage to post
1797 * Post a message on the element's #GstBus. This function takes ownership of the
1798 * message; if you want to access the message after this call, you should add an
1799 * additional reference before calling.
1801 * Returns: %TRUE if the message was successfully posted. The function returns
1802 * %FALSE if the element did not have a bus.
1807 gst_element_post_message (GstElement * element, GstMessage * message)
1810 gboolean result = FALSE;
1812 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1813 g_return_val_if_fail (message != NULL, FALSE);
1815 GST_OBJECT_LOCK (element);
1818 if (G_UNLIKELY (bus == NULL))
1821 gst_object_ref (bus);
1822 GST_OBJECT_UNLOCK (element);
1824 /* we release the element lock when posting the message so that any
1825 * (synchronous) message handlers can operate on the element */
1826 result = gst_bus_post (bus, message);
1827 gst_object_unref (bus);
1834 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1835 "not posting message %p: no bus", message);
1836 GST_OBJECT_UNLOCK (element);
1837 gst_message_unref (message);
1843 * _gst_element_error_printf:
1844 * @format: the printf-like format to use, or %NULL
1846 * This function is only used internally by the gst_element_error() macro.
1848 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1854 _gst_element_error_printf (const gchar * format, ...)
1864 va_start (args, format);
1865 buffer = g_strdup_vprintf (format, args);
1871 * gst_element_message_full:
1872 * @element: a #GstElement to send message from
1873 * @type: the #GstMessageType
1874 * @domain: the GStreamer GError domain this message belongs to
1875 * @code: the GError code belonging to the domain
1876 * @text: (allow-none) (transfer full): an allocated text string to be used
1877 * as a replacement for the default message connected to code,
1879 * @debug: (allow-none) (transfer full): an allocated debug message to be
1880 * used as a replacement for the default debugging information,
1882 * @file: the source code file where the error was generated
1883 * @function: the source code function where the error was generated
1884 * @line: the source code line where the error was generated
1886 * Post an error, warning or info message on the bus from inside an element.
1888 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1889 * #GST_MESSAGE_INFO.
1893 void gst_element_message_full
1894 (GstElement * element, GstMessageType type,
1895 GQuark domain, gint code, gchar * text,
1896 gchar * debug, const gchar * file, const gchar * function, gint line)
1898 GError *gerror = NULL;
1902 gboolean has_debug = TRUE;
1903 GstMessage *message = NULL;
1906 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1907 g_return_if_fail (GST_IS_ELEMENT (element));
1908 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1909 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1911 /* check if we send the given text or the default error text */
1912 if ((text == NULL) || (text[0] == 0)) {
1913 /* text could have come from g_strdup_printf (""); */
1915 sent_text = gst_error_get_message (domain, code);
1919 /* construct a sent_debug with extra information from source */
1920 if ((debug == NULL) || (debug[0] == 0)) {
1921 /* debug could have come from g_strdup_printf (""); */
1925 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1927 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1928 file, line, function, name, debug);
1930 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1931 file, line, function, name);
1935 /* create gerror and post message */
1936 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1938 gerror = g_error_new_literal (domain, code, sent_text);
1941 case GST_MESSAGE_ERROR:
1943 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1945 case GST_MESSAGE_WARNING:
1946 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1949 case GST_MESSAGE_INFO:
1950 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1954 g_assert_not_reached ();
1957 gst_element_post_message (element, message);
1959 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1960 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1963 g_error_free (gerror);
1964 g_free (sent_debug);
1969 * gst_element_is_locked_state:
1970 * @element: a #GstElement.
1972 * Checks if the state of an element is locked.
1973 * If the state of an element is locked, state changes of the parent don't
1974 * affect the element.
1975 * This way you can leave currently unused elements inside bins. Just lock their
1976 * state before changing the state from #GST_STATE_NULL.
1980 * Returns: TRUE, if the element's state is locked.
1983 gst_element_is_locked_state (GstElement * element)
1987 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1989 GST_OBJECT_LOCK (element);
1990 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1991 GST_OBJECT_UNLOCK (element);
1997 * gst_element_set_locked_state:
1998 * @element: a #GstElement
1999 * @locked_state: TRUE to lock the element's state
2001 * Locks the state of an element, so state changes of the parent don't affect
2002 * this element anymore.
2006 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
2007 * or the elements state-locking needed no change.
2010 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2014 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2016 GST_OBJECT_LOCK (element);
2017 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2019 if (G_UNLIKELY (old == locked_state))
2023 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2024 GST_ELEMENT_NAME (element));
2025 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
2027 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2028 GST_ELEMENT_NAME (element));
2029 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
2031 GST_OBJECT_UNLOCK (element);
2037 GST_CAT_DEBUG (GST_CAT_STATES,
2038 "elements %s was already in locked state %d",
2039 GST_ELEMENT_NAME (element), old);
2040 GST_OBJECT_UNLOCK (element);
2047 * gst_element_sync_state_with_parent:
2048 * @element: a #GstElement.
2050 * Tries to change the state of the element to the same as its parent.
2051 * If this function returns FALSE, the state of element is undefined.
2053 * Returns: TRUE, if the element's state could be synced to the parent's state.
2058 gst_element_sync_state_with_parent (GstElement * element)
2062 GstStateChangeReturn ret;
2064 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2066 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2067 GstState parent_current, parent_pending;
2069 GST_OBJECT_LOCK (parent);
2070 parent_current = GST_STATE (parent);
2071 parent_pending = GST_STATE_PENDING (parent);
2072 GST_OBJECT_UNLOCK (parent);
2074 /* set to pending if there is one, else we set it to the current state of
2076 if (parent_pending != GST_STATE_VOID_PENDING)
2077 target = parent_pending;
2079 target = parent_current;
2081 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2082 "syncing state (%s) to parent %s %s (%s, %s)",
2083 gst_element_state_get_name (GST_STATE (element)),
2084 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2085 gst_element_state_get_name (parent_current),
2086 gst_element_state_get_name (parent_pending));
2088 ret = gst_element_set_state (element, target);
2089 if (ret == GST_STATE_CHANGE_FAILURE)
2092 gst_object_unref (parent);
2096 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2103 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2104 "syncing state failed (%s)",
2105 gst_element_state_change_return_get_name (ret));
2106 gst_object_unref (parent);
2112 static GstStateChangeReturn
2113 gst_element_get_state_func (GstElement * element,
2114 GstState * state, GstState * pending, GstClockTime timeout)
2116 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2117 GstState old_pending;
2119 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2120 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2122 GST_OBJECT_LOCK (element);
2123 ret = GST_STATE_RETURN (element);
2124 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2125 gst_element_state_change_return_get_name (ret));
2127 /* we got an error, report immediately */
2128 if (ret == GST_STATE_CHANGE_FAILURE)
2131 /* we got no_preroll, report immediatly */
2132 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2135 /* no need to wait async if we are not async */
2136 if (ret != GST_STATE_CHANGE_ASYNC)
2139 old_pending = GST_STATE_PENDING (element);
2140 if (old_pending != GST_STATE_VOID_PENDING) {
2141 GTimeVal *timeval, abstimeout;
2144 if (timeout != GST_CLOCK_TIME_NONE) {
2145 glong add = timeout / 1000;
2150 /* make timeout absolute */
2151 g_get_current_time (&abstimeout);
2152 g_time_val_add (&abstimeout, add);
2153 timeval = &abstimeout;
2157 /* get cookie to detect state changes during waiting */
2158 cookie = element->state_cookie;
2160 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2161 "waiting for element to commit state");
2163 /* we have a pending state change, wait for it to complete */
2164 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2165 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2166 /* timeout triggered */
2167 ret = GST_STATE_CHANGE_ASYNC;
2169 if (cookie != element->state_cookie)
2172 /* could be success or failure */
2173 if (old_pending == GST_STATE (element)) {
2174 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2175 ret = GST_STATE_CHANGE_SUCCESS;
2177 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2178 ret = GST_STATE_CHANGE_FAILURE;
2181 /* if nothing is pending anymore we can return SUCCESS */
2182 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2183 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2184 ret = GST_STATE_CHANGE_SUCCESS;
2190 *state = GST_STATE (element);
2192 *pending = GST_STATE_PENDING (element);
2194 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2195 "state current: %s, pending: %s, result: %s",
2196 gst_element_state_get_name (GST_STATE (element)),
2197 gst_element_state_get_name (GST_STATE_PENDING (element)),
2198 gst_element_state_change_return_get_name (ret));
2199 GST_OBJECT_UNLOCK (element);
2206 *state = GST_STATE_VOID_PENDING;
2208 *pending = GST_STATE_VOID_PENDING;
2210 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2212 GST_OBJECT_UNLOCK (element);
2214 return GST_STATE_CHANGE_FAILURE;
2219 * gst_element_get_state:
2220 * @element: a #GstElement to get the state of.
2221 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2223 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2224 * state. Can be %NULL.
2225 * @timeout: a #GstClockTime to specify the timeout for an async
2226 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2228 * Gets the state of the element.
2230 * For elements that performed an ASYNC state change, as reported by
2231 * gst_element_set_state(), this function will block up to the
2232 * specified timeout value for the state change to complete.
2233 * If the element completes the state change or goes into
2234 * an error, this function returns immediately with a return value of
2235 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2237 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2238 * returns the current and pending state immediately.
2240 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2241 * successfully changed its state but is not able to provide data yet.
2242 * This mostly happens for live sources that only produce data in
2243 * %GST_STATE_PLAYING. While the state change return is equivalent to
2244 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2245 * some sink elements might not be able to complete their state change because
2246 * an element is not producing data to complete the preroll. When setting the
2247 * element to playing, the preroll will complete and playback will start.
2249 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2250 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2251 * element is still performing a state change or
2252 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2256 GstStateChangeReturn
2257 gst_element_get_state (GstElement * element,
2258 GstState * state, GstState * pending, GstClockTime timeout)
2260 GstElementClass *oclass;
2261 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2263 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2265 oclass = GST_ELEMENT_GET_CLASS (element);
2267 if (oclass->get_state)
2268 result = (oclass->get_state) (element, state, pending, timeout);
2274 * gst_element_abort_state:
2275 * @element: a #GstElement to abort the state of.
2277 * Abort the state change of the element. This function is used
2278 * by elements that do asynchronous state changes and find out
2279 * something is wrong.
2281 * This function should be called with the STATE_LOCK held.
2286 gst_element_abort_state (GstElement * element)
2290 #ifndef GST_DISABLE_GST_DEBUG
2294 g_return_if_fail (GST_IS_ELEMENT (element));
2296 GST_OBJECT_LOCK (element);
2297 pending = GST_STATE_PENDING (element);
2299 if (pending == GST_STATE_VOID_PENDING ||
2300 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2301 goto nothing_aborted;
2303 #ifndef GST_DISABLE_GST_DEBUG
2304 old_state = GST_STATE (element);
2306 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2307 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2308 gst_element_state_get_name (pending));
2312 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2314 GST_STATE_BROADCAST (element);
2315 GST_OBJECT_UNLOCK (element);
2321 GST_OBJECT_UNLOCK (element);
2326 /* Not static because GstBin has manual state handling too */
2328 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2329 GstState newstate, GstState pending)
2331 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2332 GstMessage *message;
2334 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2335 "notifying about state-changed %s to %s (%s pending)",
2336 gst_element_state_get_name (oldstate),
2337 gst_element_state_get_name (newstate),
2338 gst_element_state_get_name (pending));
2340 if (klass->state_changed)
2341 klass->state_changed (element, oldstate, newstate, pending);
2343 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2344 oldstate, newstate, pending);
2345 gst_element_post_message (element, message);
2349 * gst_element_continue_state:
2350 * @element: a #GstElement to continue the state change of.
2351 * @ret: The previous state return value
2353 * Commit the state change of the element and proceed to the next
2354 * pending state if any. This function is used
2355 * by elements that do asynchronous state changes.
2356 * The core will normally call this method automatically when an
2357 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2359 * If after calling this method the element still has not reached
2360 * the pending state, the next state change is performed.
2362 * This method is used internally and should normally not be called by plugins
2365 * Returns: The result of the commit state change.
2369 GstStateChangeReturn
2370 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2372 GstStateChangeReturn old_ret;
2373 GstState old_state, old_next;
2374 GstState current, next, pending;
2375 GstStateChange transition;
2377 GST_OBJECT_LOCK (element);
2378 old_ret = GST_STATE_RETURN (element);
2379 GST_STATE_RETURN (element) = ret;
2380 pending = GST_STATE_PENDING (element);
2382 /* check if there is something to commit */
2383 if (pending == GST_STATE_VOID_PENDING)
2384 goto nothing_pending;
2386 old_state = GST_STATE (element);
2387 /* this is the state we should go to next */
2388 old_next = GST_STATE_NEXT (element);
2389 /* update current state */
2390 current = GST_STATE (element) = old_next;
2392 /* see if we reached the final state */
2393 if (pending == current)
2396 next = GST_STATE_GET_NEXT (current, pending);
2397 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2399 GST_STATE_NEXT (element) = next;
2401 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2402 GST_OBJECT_UNLOCK (element);
2404 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2405 "committing state from %s to %s, pending %s, next %s",
2406 gst_element_state_get_name (old_state),
2407 gst_element_state_get_name (old_next),
2408 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2410 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2412 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2413 "continue state change %s to %s, final %s",
2414 gst_element_state_get_name (current),
2415 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2417 ret = gst_element_change_state (element, transition);
2423 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2424 GST_OBJECT_UNLOCK (element);
2429 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2430 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2432 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2433 "completed state change to %s", gst_element_state_get_name (pending));
2434 GST_OBJECT_UNLOCK (element);
2436 /* don't post silly messages with the same state. This can happen
2437 * when an element state is changed to what it already was. For bins
2438 * this can be the result of a lost state, which we check with the
2439 * previous return value.
2440 * We do signal the cond though as a _get_state() might be blocking
2442 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2443 _priv_gst_element_state_changed (element, old_state, old_next,
2444 GST_STATE_VOID_PENDING);
2446 GST_STATE_BROADCAST (element);
2453 * gst_element_lost_state_full:
2454 * @element: a #GstElement the state is lost of
2455 * @new_base_time: if a new base time should be distributed
2457 * Brings the element to the lost state. The current state of the
2458 * element is copied to the pending state so that any call to
2459 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2461 * An ASYNC_START message is posted with indication to distribute a new
2462 * base_time to the element when @new_base_time is %TRUE.
2463 * If the element was PLAYING, it will go to PAUSED. The element
2464 * will be restored to its PLAYING state by the parent pipeline when it
2467 * This is mostly used for elements that lost their preroll buffer
2468 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2469 * they will go to their pending state again when a new preroll buffer is
2470 * queued. This function can only be called when the element is currently
2471 * not in error or an async state change.
2473 * This function is used internally and should normally not be called from
2474 * plugins or applications.
2481 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2483 GstState old_state, new_state;
2484 GstMessage *message;
2486 g_return_if_fail (GST_IS_ELEMENT (element));
2488 GST_OBJECT_LOCK (element);
2489 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2492 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2493 goto only_async_start;
2495 old_state = GST_STATE (element);
2497 /* when we were PLAYING, the new state is PAUSED. We will also not
2498 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2499 * when we preroll. */
2500 if (old_state > GST_STATE_PAUSED)
2501 new_state = GST_STATE_PAUSED;
2503 new_state = old_state;
2505 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2506 "lost state of %s to %s", gst_element_state_get_name (old_state),
2507 gst_element_state_get_name (new_state));
2509 GST_STATE (element) = new_state;
2510 GST_STATE_NEXT (element) = new_state;
2511 GST_STATE_PENDING (element) = new_state;
2512 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2514 GST_ELEMENT_START_TIME (element) = 0;
2515 GST_OBJECT_UNLOCK (element);
2517 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2520 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2521 gst_element_post_message (element, message);
2527 GST_OBJECT_UNLOCK (element);
2532 GST_OBJECT_UNLOCK (element);
2534 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2535 gst_element_post_message (element, message);
2541 * gst_element_lost_state:
2542 * @element: a #GstElement the state is lost of
2544 * Brings the element to the lost state. This function calls
2545 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2547 * This function is used internally and should normally not be called from
2548 * plugins or applications.
2553 gst_element_lost_state (GstElement * element)
2555 gst_element_lost_state_full (element, TRUE);
2559 * gst_element_set_state:
2560 * @element: a #GstElement to change state of.
2561 * @state: the element's new #GstState.
2563 * Sets the state of the element. This function will try to set the
2564 * requested state by going through all the intermediary states and calling
2565 * the class's state change function for each.
2567 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2568 * element will perform the remainder of the state change asynchronously in
2570 * An application can use gst_element_get_state() to wait for the completion
2571 * of the state change or it can wait for a state change message on the bus.
2573 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2574 * #GST_STATE_CHANGE_ASYNC.
2576 * Returns: Result of the state change using #GstStateChangeReturn.
2580 GstStateChangeReturn
2581 gst_element_set_state (GstElement * element, GstState state)
2583 GstElementClass *oclass;
2584 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2586 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2588 oclass = GST_ELEMENT_GET_CLASS (element);
2590 if (oclass->set_state)
2591 result = (oclass->set_state) (element, state);
2597 * default set state function, calculates the next state based
2598 * on current state and calls the change_state function
2600 static GstStateChangeReturn
2601 gst_element_set_state_func (GstElement * element, GstState state)
2603 GstState current, next, old_pending;
2604 GstStateChangeReturn ret;
2605 GstStateChange transition;
2606 GstStateChangeReturn old_ret;
2608 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2610 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2611 gst_element_state_get_name (state));
2613 /* state lock is taken to protect the set_state() and get_state()
2614 * procedures, it does not lock any variables. */
2615 GST_STATE_LOCK (element);
2617 /* now calculate how to get to the new state */
2618 GST_OBJECT_LOCK (element);
2619 old_ret = GST_STATE_RETURN (element);
2620 /* previous state change returned an error, remove all pending
2621 * and next states */
2622 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2623 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2624 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2625 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2628 current = GST_STATE (element);
2629 next = GST_STATE_NEXT (element);
2630 old_pending = GST_STATE_PENDING (element);
2632 /* this is the (new) state we should go to. TARGET is the last state we set on
2634 if (state != GST_STATE_TARGET (element)) {
2635 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2636 "setting target state to %s", gst_element_state_get_name (state));
2637 GST_STATE_TARGET (element) = state;
2638 /* increment state cookie so that we can track each state change. We only do
2639 * this if this is actually a new state change. */
2640 element->state_cookie++;
2642 GST_STATE_PENDING (element) = state;
2644 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2645 "current %s, old_pending %s, next %s, old return %s",
2646 gst_element_state_get_name (current),
2647 gst_element_state_get_name (old_pending),
2648 gst_element_state_get_name (next),
2649 gst_element_state_change_return_get_name (old_ret));
2651 /* if the element was busy doing a state change, we just update the
2652 * target state, it'll get to it async then. */
2653 if (old_pending != GST_STATE_VOID_PENDING) {
2654 /* upwards state change will happen ASYNC */
2655 if (old_pending <= state)
2657 /* element is going to this state already */
2658 else if (next == state)
2660 /* element was performing an ASYNC upward state change and
2661 * we request to go downward again. Start from the next pending
2663 else if (next > state
2664 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2668 next = GST_STATE_GET_NEXT (current, state);
2669 /* now we store the next state */
2670 GST_STATE_NEXT (element) = next;
2671 /* mark busy, we need to check that there is actually a state change
2672 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2673 * the default element change_state function has no way to know what the
2674 * old value was... could consider this a FIXME...*/
2675 if (current != next)
2676 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2678 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2680 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2681 "%s: setting state from %s to %s",
2682 (next != state ? "intermediate" : "final"),
2683 gst_element_state_get_name (current), gst_element_state_get_name (next));
2685 /* now signal any waiters, they will error since the cookie was incremented */
2686 GST_STATE_BROADCAST (element);
2688 GST_OBJECT_UNLOCK (element);
2690 ret = gst_element_change_state (element, transition);
2692 GST_STATE_UNLOCK (element);
2694 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2695 gst_element_state_change_return_get_name (ret));
2701 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2702 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2703 "element was busy with async state change");
2704 GST_OBJECT_UNLOCK (element);
2706 GST_STATE_UNLOCK (element);
2708 return GST_STATE_CHANGE_ASYNC;
2713 * gst_element_change_state:
2714 * @element: a #GstElement
2715 * @transition: the requested transition
2717 * Perform @transition on @element.
2719 * This function must be called with STATE_LOCK held and is mainly used
2722 * Returns: the #GstStateChangeReturn of the state transition.
2724 GstStateChangeReturn
2725 gst_element_change_state (GstElement * element, GstStateChange transition)
2727 GstElementClass *oclass;
2728 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2730 oclass = GST_ELEMENT_GET_CLASS (element);
2732 /* call the state change function so it can set the state */
2733 if (oclass->change_state)
2734 ret = (oclass->change_state) (element, transition);
2736 ret = GST_STATE_CHANGE_FAILURE;
2739 case GST_STATE_CHANGE_FAILURE:
2740 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2741 "have FAILURE change_state return");
2742 /* state change failure */
2743 gst_element_abort_state (element);
2745 case GST_STATE_CHANGE_ASYNC:
2749 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2750 "element will change state ASYNC");
2752 target = GST_STATE_TARGET (element);
2754 if (target > GST_STATE_READY)
2757 /* else we just continue the state change downwards */
2758 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2759 "forcing commit state %s <= %s",
2760 gst_element_state_get_name (target),
2761 gst_element_state_get_name (GST_STATE_READY));
2763 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2766 case GST_STATE_CHANGE_SUCCESS:
2767 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2768 "element changed state SUCCESS");
2769 /* we can commit the state now which will proceeed to
2771 ret = gst_element_continue_state (element, ret);
2773 case GST_STATE_CHANGE_NO_PREROLL:
2774 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2775 "element changed state NO_PREROLL");
2776 /* we can commit the state now which will proceeed to
2778 ret = gst_element_continue_state (element, ret);
2781 goto invalid_return;
2784 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2789 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2797 GST_OBJECT_LOCK (element);
2798 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2799 g_critical ("%s: unknown return value %d from a state change function",
2800 GST_ELEMENT_NAME (element), ret);
2802 /* we are in error now */
2803 ret = GST_STATE_CHANGE_FAILURE;
2804 GST_STATE_RETURN (element) = ret;
2805 GST_OBJECT_UNLOCK (element);
2811 /* gst_iterator_fold functions for pads_activate
2812 * Stop the iterator if activating one pad failed. */
2814 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2816 gboolean cont = TRUE;
2818 if (!(cont = gst_pad_set_active (pad, *active)))
2819 g_value_set_boolean (ret, FALSE);
2821 /* unref the object that was reffed for us by _fold */
2822 gst_object_unref (pad);
2826 /* set the caps on the pad to NULL */
2828 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2830 gst_pad_set_caps (pad, NULL);
2831 gst_object_unref (pad);
2835 /* returns false on error or early cutout of the fold, true if all
2836 * pads in @iter were (de)activated successfully. */
2838 iterator_activate_fold_with_resync (GstIterator * iter,
2839 GstIteratorFoldFunction func, gpointer user_data)
2841 GstIteratorResult ires;
2844 /* no need to unset this later, it's just a boolean */
2845 g_value_init (&ret, G_TYPE_BOOLEAN);
2846 g_value_set_boolean (&ret, TRUE);
2849 ires = gst_iterator_fold (iter, func, &ret, user_data);
2851 case GST_ITERATOR_RESYNC:
2852 /* need to reset the result again */
2853 g_value_set_boolean (&ret, TRUE);
2854 gst_iterator_resync (iter);
2856 case GST_ITERATOR_DONE:
2857 /* all pads iterated, return collected value */
2860 /* iterator returned _ERROR or premature end with _OK,
2861 * mark an error and exit */
2862 g_value_set_boolean (&ret, FALSE);
2867 /* return collected value */
2868 return g_value_get_boolean (&ret);
2871 /* is called with STATE_LOCK
2873 * Pads are activated from source pads to sinkpads.
2876 gst_element_pads_activate (GstElement * element, gboolean active)
2881 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2882 "pads_activate with active %d", active);
2884 iter = gst_element_iterate_src_pads (element);
2886 iterator_activate_fold_with_resync (iter,
2887 (GstIteratorFoldFunction) activate_pads, &active);
2888 gst_iterator_free (iter);
2889 if (G_UNLIKELY (!res))
2892 iter = gst_element_iterate_sink_pads (element);
2894 iterator_activate_fold_with_resync (iter,
2895 (GstIteratorFoldFunction) activate_pads, &active);
2896 gst_iterator_free (iter);
2897 if (G_UNLIKELY (!res))
2901 /* clear the caps on all pads, this should never fail */
2902 iter = gst_element_iterate_pads (element);
2904 iterator_activate_fold_with_resync (iter,
2905 (GstIteratorFoldFunction) clear_caps, &active);
2906 gst_iterator_free (iter);
2907 if (G_UNLIKELY (!res))
2911 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2912 "pads_activate successful");
2919 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2920 "source pads_activate failed");
2925 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2926 "sink pads_activate failed");
2931 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2932 "failed to clear caps on pads");
2937 /* is called with STATE_LOCK */
2938 static GstStateChangeReturn
2939 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2941 GstState state, next;
2942 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2945 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2947 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2948 next = GST_STATE_TRANSITION_NEXT (transition);
2950 /* if the element already is in the given state, we just return success */
2951 if (next == GST_STATE_VOID_PENDING || state == next)
2954 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2955 "default handler tries setting state from %s to %s (%04x)",
2956 gst_element_state_get_name (state),
2957 gst_element_state_get_name (next), transition);
2959 switch (transition) {
2960 case GST_STATE_CHANGE_NULL_TO_READY:
2962 case GST_STATE_CHANGE_READY_TO_PAUSED:
2963 if (!gst_element_pads_activate (element, TRUE)) {
2964 result = GST_STATE_CHANGE_FAILURE;
2967 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2969 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2971 case GST_STATE_CHANGE_PAUSED_TO_READY:
2972 case GST_STATE_CHANGE_READY_TO_NULL:
2973 /* deactivate pads in both cases, since they are activated on
2974 ready->paused but the element might not have made it to paused */
2975 if (!gst_element_pads_activate (element, FALSE)) {
2976 result = GST_STATE_CHANGE_FAILURE;
2978 gst_element_set_base_time (element, 0);
2981 /* In null state release the reference to the clock */
2982 GST_OBJECT_LOCK (element);
2983 clock_p = &element->clock;
2984 gst_object_replace ((GstObject **) clock_p, NULL);
2985 GST_OBJECT_UNLOCK (element);
2988 /* this will catch real but unhandled state changes;
2989 * can only be caused by:
2990 * - a new state was added
2991 * - somehow the element was asked to jump across an intermediate state
2993 g_warning ("Unhandled state change from %s to %s",
2994 gst_element_state_get_name (state),
2995 gst_element_state_get_name (next));
3002 GST_OBJECT_LOCK (element);
3003 result = GST_STATE_RETURN (element);
3004 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3005 "element is already in the %s state",
3006 gst_element_state_get_name (state));
3007 GST_OBJECT_UNLOCK (element);
3014 * gst_element_get_factory:
3015 * @element: a #GstElement to request the element factory of.
3017 * Retrieves the factory that was used to create this element.
3019 * Returns: (transfer none): the #GstElementFactory used for creating this
3020 * element. no refcounting is needed.
3023 gst_element_get_factory (GstElement * element)
3025 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3027 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3031 gst_element_dispose (GObject * object)
3033 GstElement *element = GST_ELEMENT_CAST (object);
3037 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
3039 if (GST_STATE (element) != GST_STATE_NULL)
3042 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3043 "removing %d pads", g_list_length (element->pads));
3044 /* first we break all our links with the outside */
3045 while (element->pads && element->pads->data) {
3046 /* don't call _remove_pad with NULL */
3047 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
3049 if (G_UNLIKELY (element->pads != NULL)) {
3050 g_critical ("could not remove pads from element %s",
3051 GST_STR_NULL (GST_OBJECT_NAME (object)));
3054 GST_OBJECT_LOCK (element);
3055 clock_p = &element->clock;
3056 bus_p = &element->bus;
3057 gst_object_replace ((GstObject **) clock_p, NULL);
3058 gst_object_replace ((GstObject **) bus_p, NULL);
3059 GST_OBJECT_UNLOCK (element);
3061 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
3063 G_OBJECT_CLASS (parent_class)->dispose (object);
3072 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
3074 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3076 "You need to explicitly set elements to the NULL state before\n"
3077 "dropping the final reference, to allow them to clean up.\n"
3078 "This problem may also be caused by a refcounting bug in the\n"
3079 "application or some element.\n",
3080 GST_OBJECT_NAME (element),
3081 gst_element_state_get_name (GST_STATE (element)),
3082 is_locked ? " (locked)" : "");
3088 gst_element_finalize (GObject * object)
3090 GstElement *element = GST_ELEMENT_CAST (object);
3092 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
3094 GST_STATE_LOCK (element);
3095 if (element->state_cond)
3096 g_cond_free (element->state_cond);
3097 element->state_cond = NULL;
3098 GST_STATE_UNLOCK (element);
3099 g_static_rec_mutex_free (element->state_lock);
3100 g_slice_free (GStaticRecMutex, element->state_lock);
3101 element->state_lock = NULL;
3103 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
3105 G_OBJECT_CLASS (parent_class)->finalize (object);
3108 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
3110 * gst_element_save_thyself:
3111 * @element: a #GstElement to save.
3112 * @parent: the xml parent node.
3114 * Saves the element as part of the given XML structure.
3116 * Returns: the new #xmlNodePtr.
3119 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
3122 GstElementClass *oclass;
3123 GParamSpec **specs, *spec;
3126 GValue value = { 0, };
3127 GstElement *element;
3129 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
3131 element = GST_ELEMENT_CAST (object);
3133 oclass = GST_ELEMENT_GET_CLASS (element);
3135 xmlNewChild (parent, NULL, (xmlChar *) "name",
3136 (xmlChar *) GST_ELEMENT_NAME (element));
3138 if (oclass->elementfactory != NULL) {
3139 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
3141 xmlNewChild (parent, NULL, (xmlChar *) "type",
3142 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
3146 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
3148 for (i = 0; i < nspecs; i++) {
3150 if (spec->flags & G_PARAM_READABLE) {
3154 g_value_init (&value, spec->value_type);
3156 g_object_get_property (G_OBJECT (element), spec->name, &value);
3157 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
3158 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
3160 if (G_IS_PARAM_SPEC_STRING (spec))
3161 contents = g_value_dup_string (&value);
3162 else if (G_IS_PARAM_SPEC_ENUM (spec))
3163 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
3164 else if (G_IS_PARAM_SPEC_INT64 (spec))
3165 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
3166 g_value_get_int64 (&value));
3167 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
3168 if (g_value_get_boxed (&value) != NULL) {
3169 contents = g_strdup_value_contents (&value);
3171 contents = g_strdup ("NULL");
3174 contents = g_strdup_value_contents (&value);
3176 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
3179 g_value_unset (&value);
3185 pads = g_list_last (GST_ELEMENT_PADS (element));
3188 GstPad *pad = GST_PAD_CAST (pads->data);
3190 /* figure out if it's a direct pad or a ghostpad */
3191 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
3192 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
3194 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
3196 pads = g_list_previous (pads);
3203 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3205 xmlNodePtr children;
3206 GstElement *element;
3208 gchar *value = NULL;
3210 element = GST_ELEMENT_CAST (object);
3211 g_return_if_fail (element != NULL);
3214 children = self->xmlChildrenNode;
3216 if (!strcmp ((char *) children->name, "param")) {
3217 xmlNodePtr child = children->xmlChildrenNode;
3220 if (!strcmp ((char *) child->name, "name")) {
3221 name = (gchar *) xmlNodeGetContent (child);
3222 } else if (!strcmp ((char *) child->name, "value")) {
3223 value = (gchar *) xmlNodeGetContent (child);
3225 child = child->next;
3227 /* FIXME: can this just be g_object_set ? */
3228 gst_util_set_object_arg (G_OBJECT (element), name, value);
3229 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3233 children = children->next;
3237 children = self->xmlChildrenNode;
3239 if (!strcmp ((char *) children->name, "pad")) {
3240 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3242 children = children->next;
3245 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3246 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3248 #endif /* GST_DISABLE_LOADSAVE */
3251 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3255 g_return_if_fail (GST_IS_ELEMENT (element));
3257 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3259 GST_OBJECT_LOCK (element);
3260 bus_p = &GST_ELEMENT_BUS (element);
3261 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3262 GST_OBJECT_UNLOCK (element);
3266 * gst_element_set_bus:
3267 * @element: a #GstElement to set the bus of.
3268 * @bus: (transfer none): the #GstBus to set.
3270 * Sets the bus of the element. Increases the refcount on the bus.
3271 * For internal use only, unless you're testing elements.
3276 gst_element_set_bus (GstElement * element, GstBus * bus)
3278 GstElementClass *oclass;
3280 g_return_if_fail (GST_IS_ELEMENT (element));
3282 oclass = GST_ELEMENT_GET_CLASS (element);
3284 if (oclass->set_bus)
3285 oclass->set_bus (element, bus);
3289 * gst_element_get_bus:
3290 * @element: a #GstElement to get the bus of.
3292 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3293 * bus for the application.
3295 * Returns: (transfer full): the element's #GstBus. unref after usage.
3300 gst_element_get_bus (GstElement * element)
3302 GstBus *result = NULL;
3304 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3306 GST_OBJECT_LOCK (element);
3307 if ((result = GST_ELEMENT_BUS (element)))
3308 gst_object_ref (result);
3309 GST_OBJECT_UNLOCK (element);
3311 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,