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 * A pad of an element can be retrieved by name with gst_element_get_pad().
45 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
47 * Elements can be linked through their pads.
48 * If the link is straightforward, use the gst_element_link()
49 * convenience function to link two elements, or gst_element_link_many()
50 * for more elements in a row.
51 * Use gst_element_link_filtered() to link two elements constrained by
52 * a specified set of #GstCaps.
53 * For finer control, use gst_element_link_pads() and
54 * gst_element_link_pads_filtered() to specify the pads to link on
55 * each element by name.
57 * Each element has a state (see #GstState). You can get and set the state
58 * of an element with gst_element_get_state() and gst_element_set_state().
59 * Setting a state triggers a #GstStateChange. To get a string representation
60 * of a #GstState, use gst_element_state_get_name().
62 * You can get and set a #GstClock on an element using gst_element_get_clock()
63 * and gst_element_set_clock().
64 * Some elements can provide a clock for the pipeline if
65 * gst_element_provides_clock() returns %TRUE. With the
66 * gst_element_provide_clock() method one can retrieve the clock provided by
68 * Not all elements require a clock to operate correctly. If
69 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
70 * element with gst_element_set_clock().
72 * Note that clock slection and distribution is normally handled by the
73 * toplevel #GstPipeline so the clock functions are only to be used in very
74 * specific situations.
76 * Last reviewed on 2009-05-29 (0.10.24)
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstelementmetadata.h"
86 #include "gstenumtypes.h"
88 #include "gstmarshal.h"
94 #include "gst-i18n-lib.h"
96 /* Element signals and args */
112 static void gst_element_class_init (GstElementClass * klass);
113 static void gst_element_init (GstElement * element);
114 static void gst_element_base_class_init (gpointer g_class);
115 static void gst_element_base_class_finalize (gpointer g_class);
117 static void gst_element_dispose (GObject * object);
118 static void gst_element_finalize (GObject * object);
120 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
121 GstStateChange transition);
122 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
123 GstState * state, GstState * pending, GstClockTime timeout);
124 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
126 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
128 static gboolean gst_element_default_send_event (GstElement * element,
130 static gboolean gst_element_default_query (GstElement * element,
133 static GstPadTemplate
134 * gst_element_class_get_request_pad_template (GstElementClass *
135 element_class, const gchar * name);
137 static GstObjectClass *parent_class = NULL;
138 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
140 /* this is used in gstelementfactory.c:gst_element_register() */
141 GQuark _gst_elementclass_factory = 0;
144 gst_element_get_type (void)
146 static volatile gsize gst_element_type = 0;
148 if (g_once_init_enter (&gst_element_type)) {
150 static const GTypeInfo element_info = {
151 sizeof (GstElementClass),
152 gst_element_base_class_init,
153 gst_element_base_class_finalize,
154 (GClassInitFunc) gst_element_class_init,
159 (GInstanceInitFunc) gst_element_init,
163 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
164 &element_info, G_TYPE_FLAG_ABSTRACT);
166 _gst_elementclass_factory =
167 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
168 g_once_init_leave (&gst_element_type, _type);
170 return gst_element_type;
174 gst_element_class_init (GstElementClass * klass)
176 GObjectClass *gobject_class;
177 GstObjectClass *gstobject_class;
179 gobject_class = (GObjectClass *) klass;
180 gstobject_class = (GstObjectClass *) klass;
182 parent_class = g_type_class_peek_parent (klass);
185 * GstElement::pad-added:
186 * @gstelement: the object which received the signal
187 * @new_pad: the pad that has been added
189 * a new #GstPad has been added to the element. Note that this signal will
190 * usually be emitted from the context of the streaming thread. Also keep in
191 * mind that if you add new elements to the pipeline in the signal handler
192 * you will need to set them to the desired target state with
193 * gst_element_set_state() or gst_element_sync_state_with_parent().
195 gst_element_signals[PAD_ADDED] =
196 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
197 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
198 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
200 * GstElement::pad-removed:
201 * @gstelement: the object which received the signal
202 * @old_pad: the pad that has been removed
204 * a #GstPad has been removed from the element
206 gst_element_signals[PAD_REMOVED] =
207 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
208 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
209 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
211 * GstElement::no-more-pads:
212 * @gstelement: the object which received the signal
214 * This signals that the element will not generate more dynamic pads.
215 * Note that this signal will usually be emitted from the context of
216 * the streaming thread.
218 gst_element_signals[NO_MORE_PADS] =
219 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
220 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
221 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
223 gobject_class->dispose = gst_element_dispose;
224 gobject_class->finalize = gst_element_finalize;
226 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
227 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
228 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
229 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
230 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
231 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
232 klass->numpadtemplates = 0;
234 klass->elementfactory = NULL;
238 gst_element_base_class_init (gpointer g_class)
240 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
241 GList *node, *padtemplates;
243 /* Copy the element details here so elements can inherit the
244 * details from their base class and classes only need to set
245 * the details in class_init instead of base_init */
246 element_class->metadata =
247 element_class->metadata ? gst_structure_copy (element_class->metadata) :
248 gst_structure_empty_new ("metadata");
250 /* Copy the pad templates so elements inherit them
251 * from their base class but elements can add pad templates in class_init
252 * instead of base_init.
254 /* FIXME: Do we consider GstPadTemplates as immutable? If so we can
255 * simply ref them instead of copying.
257 padtemplates = g_list_copy (element_class->padtemplates);
258 for (node = padtemplates; node != NULL; node = node->next) {
259 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
260 node->data = gst_pad_template_new (tmpl->name_template,
261 tmpl->direction, tmpl->presence, gst_caps_copy (tmpl->caps));
263 element_class->padtemplates = padtemplates;
265 /* set the factory, see gst_element_register() */
266 element_class->elementfactory =
267 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
268 _gst_elementclass_factory);
269 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
270 element_class->elementfactory);
274 gst_element_base_class_finalize (gpointer g_class)
276 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
278 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
279 g_list_free (klass->padtemplates);
281 gst_structure_free (klass->metadata);
285 gst_element_init (GstElement * element)
287 GST_STATE (element) = GST_STATE_NULL;
288 GST_STATE_TARGET (element) = GST_STATE_NULL;
289 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
290 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
291 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
293 /* FIXME 0.11: Store this directly in the instance struct */
294 element->state_lock = g_slice_new (GStaticRecMutex);
295 g_static_rec_mutex_init (element->state_lock);
296 element->state_cond = g_cond_new ();
300 * gst_element_release_request_pad:
301 * @element: a #GstElement to release the request pad of.
302 * @pad: the #GstPad to release.
304 * Makes the element free the previously requested pad as obtained
305 * with gst_element_get_request_pad().
307 * This does not unref the pad. If the pad was created by using
308 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
309 * followed by gst_object_unref() to free the @pad.
314 gst_element_release_request_pad (GstElement * element, GstPad * pad)
316 GstElementClass *oclass;
318 g_return_if_fail (GST_IS_ELEMENT (element));
319 g_return_if_fail (GST_IS_PAD (pad));
321 oclass = GST_ELEMENT_GET_CLASS (element);
323 /* if the element implements a custom release function we call that, else we
324 * simply remove the pad from the element */
325 if (oclass->release_pad)
326 (oclass->release_pad) (element, pad);
328 gst_element_remove_pad (element, pad);
332 * gst_element_requires_clock:
333 * @element: a #GstElement to query
335 * Query if the element requires a clock.
337 * Returns: %TRUE if the element requires a clock
342 gst_element_requires_clock (GstElement * element)
346 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
348 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
354 * gst_element_provides_clock:
355 * @element: a #GstElement to query
357 * Query if the element provides a clock. A #GstClock provided by an
358 * element can be used as the global #GstClock for the pipeline.
359 * An element that can provide a clock is only required to do so in the PAUSED
360 * state, this means when it is fully negotiated and has allocated the resources
361 * to operate the clock.
363 * Returns: %TRUE if the element provides a clock
368 gst_element_provides_clock (GstElement * element)
372 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
374 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
380 * gst_element_provide_clock:
381 * @element: a #GstElement to query
383 * Get the clock provided by the given element.
384 * <note>An element is only required to provide a clock in the PAUSED
385 * state. Some elements can provide a clock in other states.</note>
387 * Returns: (transfer full): the GstClock provided by the element or %NULL
388 * if no clock could be provided. Unref after usage.
393 gst_element_provide_clock (GstElement * element)
395 GstClock *result = NULL;
396 GstElementClass *oclass;
398 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
400 oclass = GST_ELEMENT_GET_CLASS (element);
402 if (oclass->provide_clock)
403 result = oclass->provide_clock (element);
409 * gst_element_set_clock:
410 * @element: a #GstElement to set the clock for.
411 * @clock: the #GstClock to set for the element.
413 * Sets the clock for the element. This function increases the
414 * refcount on the clock. Any previously set clock on the object
417 * Returns: %TRUE if the element accepted the clock. An element can refuse a
418 * clock when it, for example, is not able to slave its internal clock to the
419 * @clock or when it requires a specific clock to operate.
424 gst_element_set_clock (GstElement * element, GstClock * clock)
426 GstElementClass *oclass;
430 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
431 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
433 oclass = GST_ELEMENT_GET_CLASS (element);
435 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
437 if (oclass->set_clock)
438 res = oclass->set_clock (element, clock);
441 /* only update the clock pointer if the element accepted the clock */
442 GST_OBJECT_LOCK (element);
443 clock_p = &element->clock;
444 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
445 GST_OBJECT_UNLOCK (element);
451 * gst_element_get_clock:
452 * @element: a #GstElement to get the clock of.
454 * Gets the currently configured clock of the element. This is the clock as was
455 * last set with gst_element_set_clock().
457 * Returns: (transfer full): the #GstClock of the element. unref after usage.
462 gst_element_get_clock (GstElement * element)
466 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
468 GST_OBJECT_LOCK (element);
469 if ((result = element->clock))
470 gst_object_ref (result);
471 GST_OBJECT_UNLOCK (element);
477 * gst_element_set_base_time:
478 * @element: a #GstElement.
479 * @time: the base time to set.
481 * Set the base time of an element. See gst_element_get_base_time().
486 gst_element_set_base_time (GstElement * element, GstClockTime time)
490 g_return_if_fail (GST_IS_ELEMENT (element));
492 GST_OBJECT_LOCK (element);
493 old = element->base_time;
494 element->base_time = time;
495 GST_OBJECT_UNLOCK (element);
497 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
498 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
499 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
503 * gst_element_get_base_time:
504 * @element: a #GstElement.
506 * Returns the base time of the element. The base time is the
507 * absolute time of the clock when this element was last put to
508 * PLAYING. Subtracting the base time from the clock time gives
509 * the running time of the element.
511 * Returns: the base time of the element.
516 gst_element_get_base_time (GstElement * element)
520 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
522 GST_OBJECT_LOCK (element);
523 result = element->base_time;
524 GST_OBJECT_UNLOCK (element);
530 * gst_element_set_start_time:
531 * @element: a #GstElement.
532 * @time: the base time to set.
534 * Set the start time of an element. The start time of the element is the
535 * running time of the element when it last went to the PAUSED state. In READY
536 * or after a flushing seek, it is set to 0.
538 * Toplevel elements like #GstPipeline will manage the start_time and
539 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
540 * on such a toplevel element will disable the distribution of the base_time to
541 * the children and can be useful if the application manages the base_time
542 * itself, for example if you want to synchronize capture from multiple
543 * pipelines, and you can also ensure that the pipelines have the same clock.
550 gst_element_set_start_time (GstElement * element, GstClockTime time)
554 g_return_if_fail (GST_IS_ELEMENT (element));
556 GST_OBJECT_LOCK (element);
557 old = GST_ELEMENT_START_TIME (element);
558 GST_ELEMENT_START_TIME (element) = time;
559 GST_OBJECT_UNLOCK (element);
561 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
562 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
563 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
567 * gst_element_get_start_time:
568 * @element: a #GstElement.
570 * Returns the start time of the element. The start time is the
571 * running time of the clock when this element was last put to PAUSED.
573 * Usually the start_time is managed by a toplevel element such as
578 * Returns: the start time of the element.
583 gst_element_get_start_time (GstElement * element)
587 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
589 GST_OBJECT_LOCK (element);
590 result = GST_ELEMENT_START_TIME (element);
591 GST_OBJECT_UNLOCK (element);
597 * gst_element_is_indexable:
598 * @element: a #GstElement.
600 * Queries if the element can be indexed.
602 * Returns: TRUE if the element can be indexed.
607 gst_element_is_indexable (GstElement * element)
611 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
613 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
619 * gst_element_set_index:
620 * @element: a #GstElement.
621 * @index: (transfer none): a #GstIndex.
623 * Set @index on the element. The refcount of the index
624 * will be increased, any previously set index is unreffed.
629 gst_element_set_index (GstElement * element, GstIndex * index)
631 GstElementClass *oclass;
633 g_return_if_fail (GST_IS_ELEMENT (element));
634 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
636 oclass = GST_ELEMENT_GET_CLASS (element);
638 if (oclass->set_index)
639 oclass->set_index (element, index);
643 * gst_element_get_index:
644 * @element: a #GstElement.
646 * Gets the index from the element.
648 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
649 * element. unref after usage.
654 gst_element_get_index (GstElement * element)
656 GstElementClass *oclass;
657 GstIndex *result = NULL;
659 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
661 oclass = GST_ELEMENT_GET_CLASS (element);
663 if (oclass->get_index)
664 result = oclass->get_index (element);
670 * gst_element_add_pad:
671 * @element: a #GstElement to add the pad to.
672 * @pad: (transfer full): the #GstPad to add to the element.
674 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
675 * see gst_object_set_parent() for refcounting information.
677 * Pads are not automatically activated so elements should perform the needed
678 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
679 * state. See gst_pad_set_active() for more information about activating pads.
681 * The pad and the element should be unlocked when calling this function.
683 * This function will emit the #GstElement::pad-added signal on the element.
685 * Returns: %TRUE if the pad could be added. This function can fail when
686 * a pad with the same name already existed or the pad already had another
692 gst_element_add_pad (GstElement * element, GstPad * pad)
697 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
698 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
700 /* locking pad to look at the name */
701 GST_OBJECT_LOCK (pad);
702 pad_name = g_strdup (GST_PAD_NAME (pad));
703 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
704 GST_STR_NULL (pad_name));
705 flushing = GST_PAD_IS_FLUSHING (pad);
706 GST_OBJECT_UNLOCK (pad);
708 /* then check to see if there's already a pad by that name here */
709 GST_OBJECT_LOCK (element);
710 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
713 /* try to set the pad's parent */
714 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
715 GST_OBJECT_CAST (element))))
718 /* check for flushing pads */
719 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
720 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
721 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
722 "use gst_pad_set_active(pad,TRUE) before adding it.",
723 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
725 GST_OBJECT_LOCK (pad);
726 GST_PAD_UNSET_FLUSHING (pad);
727 GST_OBJECT_UNLOCK (pad);
732 /* add it to the list */
733 switch (gst_pad_get_direction (pad)) {
735 element->srcpads = g_list_prepend (element->srcpads, pad);
736 element->numsrcpads++;
739 element->sinkpads = g_list_prepend (element->sinkpads, pad);
740 element->numsinkpads++;
745 element->pads = g_list_prepend (element->pads, pad);
747 element->pads_cookie++;
748 GST_OBJECT_UNLOCK (element);
750 /* emit the PAD_ADDED signal */
751 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
758 g_critical ("Padname %s is not unique in element %s, not adding",
759 pad_name, GST_ELEMENT_NAME (element));
760 GST_OBJECT_UNLOCK (element);
767 ("Pad %s already has parent when trying to add to element %s",
768 pad_name, GST_ELEMENT_NAME (element));
769 GST_OBJECT_UNLOCK (element);
775 GST_OBJECT_LOCK (pad);
777 ("Trying to add pad %s to element %s, but it has no direction",
778 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
779 GST_OBJECT_UNLOCK (pad);
780 GST_OBJECT_UNLOCK (element);
786 * gst_element_remove_pad:
787 * @element: a #GstElement to remove pad from.
788 * @pad: (transfer none): the #GstPad to remove from the element.
790 * Removes @pad from @element. @pad will be destroyed if it has not been
791 * referenced elsewhere using gst_object_unparent().
793 * This function is used by plugin developers and should not be used
794 * by applications. Pads that were dynamically requested from elements
795 * with gst_element_get_request_pad() should be released with the
796 * gst_element_release_request_pad() function instead.
798 * Pads are not automatically deactivated so elements should perform the needed
799 * steps to deactivate the pad in case this pad is removed in the PAUSED or
800 * PLAYING state. See gst_pad_set_active() for more information about
803 * The pad and the element should be unlocked when calling this function.
805 * This function will emit the #GstElement::pad-removed signal on the element.
807 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
808 * pad does not belong to the provided element.
813 gst_element_remove_pad (GstElement * element, GstPad * pad)
817 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
818 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
820 /* locking pad to look at the name and parent */
821 GST_OBJECT_LOCK (pad);
822 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
823 GST_STR_NULL (GST_PAD_NAME (pad)));
825 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
827 GST_OBJECT_UNLOCK (pad);
830 if ((peer = gst_pad_get_peer (pad))) {
831 /* window for MT unsafeness, someone else could unlink here
832 * and then we call unlink with wrong pads. The unlink
833 * function would catch this and safely return failed. */
834 if (GST_PAD_IS_SRC (pad))
835 gst_pad_unlink (pad, peer);
837 gst_pad_unlink (peer, pad);
839 gst_object_unref (peer);
842 GST_OBJECT_LOCK (element);
843 /* remove it from the list */
844 switch (gst_pad_get_direction (pad)) {
846 element->srcpads = g_list_remove (element->srcpads, pad);
847 element->numsrcpads--;
850 element->sinkpads = g_list_remove (element->sinkpads, pad);
851 element->numsinkpads--;
854 g_critical ("Removing pad without direction???");
857 element->pads = g_list_remove (element->pads, pad);
859 element->pads_cookie++;
860 GST_OBJECT_UNLOCK (element);
862 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
863 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
865 gst_object_unparent (GST_OBJECT_CAST (pad));
872 /* FIXME, locking order? */
873 GST_OBJECT_LOCK (element);
874 g_critical ("Padname %s:%s does not belong to element %s when removing",
875 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
876 GST_OBJECT_UNLOCK (element);
877 GST_OBJECT_UNLOCK (pad);
883 * gst_element_no_more_pads:
884 * @element: a #GstElement
886 * Use this function to signal that the element does not expect any more pads
887 * to show up in the current pipeline. This function should be called whenever
888 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
889 * pad templates use this in combination with autopluggers to figure out that
890 * the element is done initializing its pads.
892 * This function emits the #GstElement::no-more-pads signal.
897 gst_element_no_more_pads (GstElement * element)
899 g_return_if_fail (GST_IS_ELEMENT (element));
901 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
905 pad_compare_name (GstPad * pad1, const gchar * name)
909 GST_OBJECT_LOCK (pad1);
910 result = strcmp (GST_PAD_NAME (pad1), name);
911 GST_OBJECT_UNLOCK (pad1);
917 * gst_element_get_static_pad:
918 * @element: a #GstElement to find a static pad of.
919 * @name: the name of the static #GstPad to retrieve.
921 * Retrieves a pad from @element by name. This version only retrieves
922 * already-existing (i.e. 'static') pads.
924 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
930 gst_element_get_static_pad (GstElement * element, const gchar * name)
933 GstPad *result = NULL;
935 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
936 g_return_val_if_fail (name != NULL, NULL);
938 GST_OBJECT_LOCK (element);
940 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
942 result = GST_PAD_CAST (find->data);
943 gst_object_ref (result);
946 if (result == NULL) {
947 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
948 name, GST_ELEMENT_NAME (element));
950 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
951 GST_ELEMENT_NAME (element), name);
953 GST_OBJECT_UNLOCK (element);
959 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
960 const gchar * name, const GstCaps * caps)
962 GstPad *newpad = NULL;
963 GstElementClass *oclass;
965 oclass = GST_ELEMENT_GET_CLASS (element);
967 #ifndef G_DISABLE_CHECKS
968 /* Some sanity checking here */
972 /* Is this the template name? */
973 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
974 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
976 const gchar *str, *data;
979 /* Otherwise check if it's a valid name for the name template */
980 str = strchr (templ->name_template, '%');
981 g_return_val_if_fail (str != NULL, NULL);
982 g_return_val_if_fail (strncmp (templ->name_template, name,
983 str - templ->name_template) == 0, NULL);
984 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
986 data = name + (str - templ->name_template);
988 /* Can either be %s or %d or %u, do sanity checking for %d */
989 if (*(str + 1) == 'd') {
993 tmp = g_ascii_strtoll (data, &endptr, 10);
994 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
995 && *endptr == '\0', NULL);
996 } else if (*(str + 1) == 'u') {
1000 tmp = g_ascii_strtoull (data, &endptr, 10);
1001 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
1005 pad = gst_element_get_static_pad (element, name);
1007 gst_object_unref (pad);
1008 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1009 g_critical ("Element %s already has a pad named %s, the behaviour of "
1010 " gst_element_get_request_pad() for existing pads is undefined!",
1011 GST_ELEMENT_NAME (element), name);
1016 if (oclass->request_new_pad)
1017 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1020 gst_object_ref (newpad);
1026 * gst_element_get_request_pad:
1027 * @element: a #GstElement to find a request pad of.
1028 * @name: the name of the request #GstPad to retrieve.
1030 * Retrieves a pad from the element by name. This version only retrieves
1031 * request pads. The pad should be released with
1032 * gst_element_release_request_pad().
1034 * This method is slow and will be deprecated in the future. New code should
1035 * use gst_element_request_pad() with the requested template.
1037 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1038 * Release after usage.
1041 gst_element_get_request_pad (GstElement * element, const gchar * name)
1043 GstPadTemplate *templ = NULL;
1045 const gchar *req_name = NULL;
1046 gboolean templ_found = FALSE;
1049 gchar *str, *endptr = NULL;
1050 GstElementClass *class;
1052 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1053 g_return_val_if_fail (name != NULL, NULL);
1055 class = GST_ELEMENT_GET_CLASS (element);
1057 /* if the name contains a %, we assume it's the complete template name. Get
1058 * the template and try to get a pad */
1059 if (strstr (name, "%")) {
1060 templ = gst_element_class_get_request_pad_template (class, name);
1065 /* there is no % in the name, try to find a matching template */
1066 list = class->padtemplates;
1067 while (!templ_found && list) {
1068 templ = (GstPadTemplate *) list->data;
1069 if (templ->presence == GST_PAD_REQUEST) {
1070 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1071 templ->name_template);
1072 /* see if we find an exact match */
1073 if (strcmp (name, templ->name_template) == 0) {
1078 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1079 and %d and %u, occurring at the end of the name_template, are the only
1081 else if ((str = strchr (templ->name_template, '%'))
1082 && strncmp (templ->name_template, name,
1083 str - templ->name_template) == 0
1084 && strlen (name) > str - templ->name_template) {
1085 data = name + (str - templ->name_template);
1086 if (*(str + 1) == 'd') {
1090 tmp = strtol (data, &endptr, 10);
1091 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1097 } else if (*(str + 1) == 'u') {
1101 tmp = strtoul (data, &endptr, 10);
1102 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1122 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1128 * gst_element_request_pad:
1129 * @element: a #GstElement to find a request pad of.
1130 * @templ: a #GstPadTemplate of which we want a pad of.
1131 * @name: (transfer none) (allow-none): the name of the request #GstPad
1132 * to retrieve. Can be %NULL.
1133 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1134 * request. Can be %NULL.
1136 * Retrieves a request pad from the element according to the provided template.
1138 * If the @caps are specified and the element implements thew new
1139 * request_new_pad_full virtual method, the element will use them to select
1140 * which pad to create.
1142 * The pad should be released with gst_element_release_request_pad().
1144 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1145 * Release after usage.
1150 gst_element_request_pad (GstElement * element,
1151 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1153 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1154 g_return_val_if_fail (templ != NULL, NULL);
1156 return _gst_element_request_pad (element, templ, name, caps);
1160 * gst_element_get_pad:
1161 * @element: a #GstElement.
1162 * @name: the name of the pad to retrieve.
1164 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1165 * first, then gst_element_get_request_pad().
1167 * Deprecated: This function is deprecated as it's unclear if the reference
1168 * to the result pad should be released with gst_object_unref() in case of a static pad
1169 * or gst_element_release_request_pad() in case of a request pad.
1170 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1172 * Returns: (transfer full): the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1173 * depending on the type of the pad.
1175 #ifndef GST_REMOVE_DEPRECATED
1176 #ifdef GST_DISABLE_DEPRECATED
1177 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1180 gst_element_get_pad (GstElement * element, const gchar * name)
1184 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1185 g_return_val_if_fail (name != NULL, NULL);
1187 pad = gst_element_get_static_pad (element, name);
1189 pad = gst_element_get_request_pad (element, name);
1193 #endif /* GST_REMOVE_DEPRECATED */
1195 static GstIterator *
1196 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1198 GstIterator *result;
1200 GST_OBJECT_LOCK (element);
1201 result = gst_iterator_new_list (GST_TYPE_PAD,
1202 GST_OBJECT_GET_LOCK (element),
1203 &element->pads_cookie, padlist, (GObject *) element, NULL);
1204 GST_OBJECT_UNLOCK (element);
1210 * gst_element_iterate_pads:
1211 * @element: a #GstElement to iterate pads of.
1213 * Retrieves an iterattor of @element's pads. The iterator should
1214 * be freed after usage.
1216 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1222 gst_element_iterate_pads (GstElement * element)
1224 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1226 return gst_element_iterate_pad_list (element, &element->pads);
1230 * gst_element_iterate_src_pads:
1231 * @element: a #GstElement.
1233 * Retrieves an iterator of @element's source pads.
1235 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1241 gst_element_iterate_src_pads (GstElement * element)
1243 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1245 return gst_element_iterate_pad_list (element, &element->srcpads);
1249 * gst_element_iterate_sink_pads:
1250 * @element: a #GstElement.
1252 * Retrieves an iterator of @element's sink pads.
1254 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1260 gst_element_iterate_sink_pads (GstElement * element)
1262 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1264 return gst_element_iterate_pad_list (element, &element->sinkpads);
1268 * gst_element_class_add_pad_template:
1269 * @klass: the #GstElementClass to add the pad template to.
1270 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1272 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1273 * functions of classes. If a pad template with the same name as an already
1274 * existing one is added the old one is replaced by the new one.
1278 gst_element_class_add_pad_template (GstElementClass * klass,
1279 GstPadTemplate * templ)
1281 GList *template_list = klass->padtemplates;
1283 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1284 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1286 /* If we already have a pad template with the same name replace the
1288 while (template_list) {
1289 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1291 /* Found pad with the same name, replace and return */
1292 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1293 gst_object_unref (padtempl);
1294 template_list->data = templ;
1297 template_list = g_list_next (template_list);
1300 /* Take ownership of the floating ref */
1301 g_object_ref_sink (templ);
1303 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1304 klass->numpadtemplates++;
1308 * gst_element_class_add_metadata:
1309 * @klass: class to set metadata for
1310 * @key: the key to set
1311 * @value: the value to set
1313 * Set @key with @value as metadata in @klass.
1316 gst_element_class_add_metadata (GstElementClass * klass,
1317 const gchar * key, const gchar * value)
1319 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1320 g_return_if_fail (key != NULL);
1321 g_return_if_fail (value != NULL);
1323 gst_structure_set ((GstStructure *) klass->metadata,
1324 key, G_TYPE_STRING, value, NULL);
1328 * gst_element_class_set_metadata:
1329 * @klass: class to set metadata for
1330 * @longname: The long English name of the element. E.g. "File Sink"
1331 * @classification: String describing the type of element, as an unordered list
1332 * separated with slashes ('/'). See draft-klass.txt of the design docs
1333 * for more details and common types. E.g: "Sink/File"
1334 * @description: Sentence describing the purpose of the element.
1335 * E.g: "Write stream to a file"
1336 * @author: Name and contact details of the author(s). Use \n to separate
1337 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1339 * Sets the detailed information for a #GstElementClass.
1340 * <note>This function is for use in _class_init functions only.</note>
1343 gst_element_class_set_metadata (GstElementClass * klass,
1344 const gchar * longname, const gchar * classification,
1345 const gchar * description, const gchar * author)
1347 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1349 gst_structure_set ((GstStructure *) klass->metadata,
1350 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1351 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1352 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1353 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1357 * gst_element_class_get_pad_template_list:
1358 * @element_class: a #GstElementClass to get pad templates of.
1360 * Retrieves a list of the pad templates associated with @element_class. The
1361 * list must not be modified by the calling code.
1362 * <note>If you use this function in the #GInstanceInitFunc of an object class
1363 * that has subclasses, make sure to pass the g_class parameter of the
1364 * #GInstanceInitFunc here.</note>
1366 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1370 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1372 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1374 return element_class->padtemplates;
1378 * gst_element_class_get_pad_template:
1379 * @element_class: a #GstElementClass to get the pad template of.
1380 * @name: the name of the #GstPadTemplate to get.
1382 * Retrieves a padtemplate from @element_class with the given name.
1383 * <note>If you use this function in the #GInstanceInitFunc of an object class
1384 * that has subclasses, make sure to pass the g_class parameter of the
1385 * #GInstanceInitFunc here.</note>
1387 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1388 * if none was found. No unreferencing is necessary.
1391 gst_element_class_get_pad_template (GstElementClass *
1392 element_class, const gchar * name)
1396 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1397 g_return_val_if_fail (name != NULL, NULL);
1399 padlist = element_class->padtemplates;
1402 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1404 if (strcmp (padtempl->name_template, name) == 0)
1407 padlist = g_list_next (padlist);
1413 static GstPadTemplate *
1414 gst_element_class_get_request_pad_template (GstElementClass *
1415 element_class, const gchar * name)
1417 GstPadTemplate *tmpl;
1419 tmpl = gst_element_class_get_pad_template (element_class, name);
1420 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1426 /* get a random pad on element of the given direction.
1427 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1430 gst_element_get_random_pad (GstElement * element,
1431 gboolean need_linked, GstPadDirection dir)
1433 GstPad *result = NULL;
1436 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1440 GST_OBJECT_LOCK (element);
1441 pads = element->srcpads;
1444 GST_OBJECT_LOCK (element);
1445 pads = element->sinkpads;
1448 goto wrong_direction;
1450 for (; pads; pads = g_list_next (pads)) {
1451 GstPad *pad = GST_PAD_CAST (pads->data);
1453 GST_OBJECT_LOCK (pad);
1454 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1455 GST_DEBUG_PAD_NAME (pad));
1457 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1458 /* if we require a linked pad, and it is not linked, continue the
1460 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1461 GST_DEBUG_PAD_NAME (pad));
1462 GST_OBJECT_UNLOCK (pad);
1465 /* found a pad, stop search */
1466 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1467 GST_DEBUG_PAD_NAME (pad));
1468 GST_OBJECT_UNLOCK (pad);
1474 gst_object_ref (result);
1476 GST_OBJECT_UNLOCK (element);
1480 /* ERROR handling */
1483 g_warning ("unknown pad direction %d", dir);
1489 gst_element_default_send_event (GstElement * element, GstEvent * event)
1491 gboolean result = FALSE;
1494 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1495 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1496 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1499 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1500 "pushing %s event to random %s pad %s:%s",
1501 GST_EVENT_TYPE_NAME (event),
1502 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1503 GST_DEBUG_PAD_NAME (pad));
1505 result = gst_pad_push_event (pad, event);
1506 gst_object_unref (pad);
1508 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1509 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1510 gst_event_unref (event);
1516 * gst_element_send_event:
1517 * @element: a #GstElement to send the event to.
1518 * @event: (transfer full): the #GstEvent to send to the element.
1520 * Sends an event to an element. If the element doesn't implement an
1521 * event handler, the event will be pushed on a random linked sink pad for
1522 * upstream events or a random linked source pad for downstream events.
1524 * This function takes owership of the provided event so you should
1525 * gst_event_ref() it if you want to reuse the event after this call.
1527 * Returns: %TRUE if the event was handled.
1532 gst_element_send_event (GstElement * element, GstEvent * event)
1534 GstElementClass *oclass;
1535 gboolean result = FALSE;
1537 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1538 g_return_val_if_fail (event != NULL, FALSE);
1540 oclass = GST_ELEMENT_GET_CLASS (element);
1542 GST_STATE_LOCK (element);
1543 if (oclass->send_event) {
1544 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1545 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1546 result = oclass->send_event (element, event);
1548 result = gst_element_default_send_event (element, event);
1550 GST_STATE_UNLOCK (element);
1557 * @element: a #GstElement to send the event to.
1558 * @rate: The new playback rate
1559 * @format: The format of the seek values
1560 * @flags: The optional seek flags.
1561 * @cur_type: The type and flags for the new current position
1562 * @cur: The value of the new current position
1563 * @stop_type: The type and flags for the new stop position
1564 * @stop: The value of the new stop position
1566 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1567 * the parameters. The seek event is sent to the element using
1568 * gst_element_send_event().
1570 * Returns: %TRUE if the event was handled.
1575 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1576 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1577 GstSeekType stop_type, gint64 stop)
1582 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1585 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1586 result = gst_element_send_event (element, event);
1592 * gst_element_get_query_types:
1593 * @element: a #GstElement to query
1595 * Get an array of query types from the element.
1596 * If the element doesn't implement a query types function,
1597 * the query will be forwarded to the peer of a random linked sink pad.
1599 * Returns: An array of #GstQueryType elements that should not
1600 * be freed or modified.
1604 const GstQueryType *
1605 gst_element_get_query_types (GstElement * element)
1607 GstElementClass *oclass;
1608 const GstQueryType *result = NULL;
1610 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1612 oclass = GST_ELEMENT_GET_CLASS (element);
1614 if (oclass->get_query_types) {
1615 result = oclass->get_query_types (element);
1617 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1620 GstPad *peer = gst_pad_get_peer (pad);
1623 result = gst_pad_get_query_types (peer);
1625 gst_object_unref (peer);
1627 gst_object_unref (pad);
1634 gst_element_default_query (GstElement * element, GstQuery * query)
1636 gboolean result = FALSE;
1639 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1641 result = gst_pad_query (pad, query);
1643 gst_object_unref (pad);
1645 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1647 GstPad *peer = gst_pad_get_peer (pad);
1650 result = gst_pad_query (peer, query);
1652 gst_object_unref (peer);
1654 gst_object_unref (pad);
1661 * gst_element_query:
1662 * @element: a #GstElement to perform the query on.
1663 * @query: (transfer none): the #GstQuery.
1665 * Performs a query on the given element.
1667 * For elements that don't implement a query handler, this function
1668 * forwards the query to a random srcpad or to the peer of a
1669 * random linked sinkpad of this element.
1671 * Please note that some queries might need a running pipeline to work.
1673 * Returns: TRUE if the query could be performed.
1678 gst_element_query (GstElement * element, GstQuery * query)
1680 GstElementClass *oclass;
1681 gboolean result = FALSE;
1683 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1684 g_return_val_if_fail (query != NULL, FALSE);
1686 oclass = GST_ELEMENT_GET_CLASS (element);
1688 if (oclass->query) {
1689 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1690 GST_ELEMENT_NAME (element));
1691 result = oclass->query (element, query);
1693 result = gst_element_default_query (element, query);
1699 * gst_element_post_message:
1700 * @element: a #GstElement posting the message
1701 * @message: (transfer full): a #GstMessage to post
1703 * Post a message on the element's #GstBus. This function takes ownership of the
1704 * message; if you want to access the message after this call, you should add an
1705 * additional reference before calling.
1707 * Returns: %TRUE if the message was successfully posted. The function returns
1708 * %FALSE if the element did not have a bus.
1713 gst_element_post_message (GstElement * element, GstMessage * message)
1716 gboolean result = FALSE;
1718 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1719 g_return_val_if_fail (message != NULL, FALSE);
1721 GST_OBJECT_LOCK (element);
1724 if (G_UNLIKELY (bus == NULL))
1727 gst_object_ref (bus);
1728 GST_OBJECT_UNLOCK (element);
1730 /* we release the element lock when posting the message so that any
1731 * (synchronous) message handlers can operate on the element */
1732 result = gst_bus_post (bus, message);
1733 gst_object_unref (bus);
1740 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1741 "not posting message %p: no bus", message);
1742 GST_OBJECT_UNLOCK (element);
1743 gst_message_unref (message);
1749 * _gst_element_error_printf:
1750 * @format: the printf-like format to use, or %NULL
1752 * This function is only used internally by the gst_element_error() macro.
1754 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1760 _gst_element_error_printf (const gchar * format, ...)
1770 va_start (args, format);
1771 buffer = g_strdup_vprintf (format, args);
1777 * gst_element_message_full:
1778 * @element: a #GstElement to send message from
1779 * @type: the #GstMessageType
1780 * @domain: the GStreamer GError domain this message belongs to
1781 * @code: the GError code belonging to the domain
1782 * @text: (allow-none) (transfer full): an allocated text string to be used
1783 * as a replacement for the default message connected to code,
1785 * @debug: (allow-none) (transfer full): an allocated debug message to be
1786 * used as a replacement for the default debugging information,
1788 * @file: the source code file where the error was generated
1789 * @function: the source code function where the error was generated
1790 * @line: the source code line where the error was generated
1792 * Post an error, warning or info message on the bus from inside an element.
1794 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1795 * #GST_MESSAGE_INFO.
1799 void gst_element_message_full
1800 (GstElement * element, GstMessageType type,
1801 GQuark domain, gint code, gchar * text,
1802 gchar * debug, const gchar * file, const gchar * function, gint line)
1804 GError *gerror = NULL;
1808 gboolean has_debug = TRUE;
1809 GstMessage *message = NULL;
1812 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1813 g_return_if_fail (GST_IS_ELEMENT (element));
1814 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1815 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1817 /* check if we send the given text or the default error text */
1818 if ((text == NULL) || (text[0] == 0)) {
1819 /* text could have come from g_strdup_printf (""); */
1821 sent_text = gst_error_get_message (domain, code);
1825 /* construct a sent_debug with extra information from source */
1826 if ((debug == NULL) || (debug[0] == 0)) {
1827 /* debug could have come from g_strdup_printf (""); */
1831 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1833 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1834 file, line, function, name, debug);
1836 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1837 file, line, function, name);
1841 /* create gerror and post message */
1842 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1844 gerror = g_error_new_literal (domain, code, sent_text);
1847 case GST_MESSAGE_ERROR:
1849 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1851 case GST_MESSAGE_WARNING:
1852 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1855 case GST_MESSAGE_INFO:
1856 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1860 g_assert_not_reached ();
1863 gst_element_post_message (element, message);
1865 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1866 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1869 g_error_free (gerror);
1870 g_free (sent_debug);
1875 * gst_element_is_locked_state:
1876 * @element: a #GstElement.
1878 * Checks if the state of an element is locked.
1879 * If the state of an element is locked, state changes of the parent don't
1880 * affect the element.
1881 * This way you can leave currently unused elements inside bins. Just lock their
1882 * state before changing the state from #GST_STATE_NULL.
1886 * Returns: TRUE, if the element's state is locked.
1889 gst_element_is_locked_state (GstElement * element)
1893 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1895 GST_OBJECT_LOCK (element);
1896 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1897 GST_OBJECT_UNLOCK (element);
1903 * gst_element_set_locked_state:
1904 * @element: a #GstElement
1905 * @locked_state: TRUE to lock the element's state
1907 * Locks the state of an element, so state changes of the parent don't affect
1908 * this element anymore.
1912 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1913 * or the elements state-locking needed no change.
1916 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1920 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1922 GST_OBJECT_LOCK (element);
1923 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1925 if (G_UNLIKELY (old == locked_state))
1929 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1930 GST_ELEMENT_NAME (element));
1931 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1933 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1934 GST_ELEMENT_NAME (element));
1935 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1937 GST_OBJECT_UNLOCK (element);
1943 GST_CAT_DEBUG (GST_CAT_STATES,
1944 "elements %s was already in locked state %d",
1945 GST_ELEMENT_NAME (element), old);
1946 GST_OBJECT_UNLOCK (element);
1953 * gst_element_sync_state_with_parent:
1954 * @element: a #GstElement.
1956 * Tries to change the state of the element to the same as its parent.
1957 * If this function returns FALSE, the state of element is undefined.
1959 * Returns: TRUE, if the element's state could be synced to the parent's state.
1964 gst_element_sync_state_with_parent (GstElement * element)
1968 GstStateChangeReturn ret;
1970 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1972 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1973 GstState parent_current, parent_pending;
1975 GST_OBJECT_LOCK (parent);
1976 parent_current = GST_STATE (parent);
1977 parent_pending = GST_STATE_PENDING (parent);
1978 GST_OBJECT_UNLOCK (parent);
1980 /* set to pending if there is one, else we set it to the current state of
1982 if (parent_pending != GST_STATE_VOID_PENDING)
1983 target = parent_pending;
1985 target = parent_current;
1987 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1988 "syncing state (%s) to parent %s %s (%s, %s)",
1989 gst_element_state_get_name (GST_STATE (element)),
1990 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1991 gst_element_state_get_name (parent_current),
1992 gst_element_state_get_name (parent_pending));
1994 ret = gst_element_set_state (element, target);
1995 if (ret == GST_STATE_CHANGE_FAILURE)
1998 gst_object_unref (parent);
2002 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2009 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2010 "syncing state failed (%s)",
2011 gst_element_state_change_return_get_name (ret));
2012 gst_object_unref (parent);
2018 static GstStateChangeReturn
2019 gst_element_get_state_func (GstElement * element,
2020 GstState * state, GstState * pending, GstClockTime timeout)
2022 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2023 GstState old_pending;
2025 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2026 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2028 GST_OBJECT_LOCK (element);
2029 ret = GST_STATE_RETURN (element);
2030 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2031 gst_element_state_change_return_get_name (ret));
2033 /* we got an error, report immediately */
2034 if (ret == GST_STATE_CHANGE_FAILURE)
2037 /* we got no_preroll, report immediatly */
2038 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2041 /* no need to wait async if we are not async */
2042 if (ret != GST_STATE_CHANGE_ASYNC)
2045 old_pending = GST_STATE_PENDING (element);
2046 if (old_pending != GST_STATE_VOID_PENDING) {
2047 GTimeVal *timeval, abstimeout;
2050 if (timeout != GST_CLOCK_TIME_NONE) {
2051 glong add = timeout / 1000;
2056 /* make timeout absolute */
2057 g_get_current_time (&abstimeout);
2058 g_time_val_add (&abstimeout, add);
2059 timeval = &abstimeout;
2063 /* get cookie to detect state changes during waiting */
2064 cookie = element->state_cookie;
2066 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2067 "waiting for element to commit state");
2069 /* we have a pending state change, wait for it to complete */
2070 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2071 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2072 /* timeout triggered */
2073 ret = GST_STATE_CHANGE_ASYNC;
2075 if (cookie != element->state_cookie)
2078 /* could be success or failure */
2079 if (old_pending == GST_STATE (element)) {
2080 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2081 ret = GST_STATE_CHANGE_SUCCESS;
2083 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2084 ret = GST_STATE_CHANGE_FAILURE;
2087 /* if nothing is pending anymore we can return SUCCESS */
2088 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2089 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2090 ret = GST_STATE_CHANGE_SUCCESS;
2096 *state = GST_STATE (element);
2098 *pending = GST_STATE_PENDING (element);
2100 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2101 "state current: %s, pending: %s, result: %s",
2102 gst_element_state_get_name (GST_STATE (element)),
2103 gst_element_state_get_name (GST_STATE_PENDING (element)),
2104 gst_element_state_change_return_get_name (ret));
2105 GST_OBJECT_UNLOCK (element);
2112 *state = GST_STATE_VOID_PENDING;
2114 *pending = GST_STATE_VOID_PENDING;
2116 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2118 GST_OBJECT_UNLOCK (element);
2120 return GST_STATE_CHANGE_FAILURE;
2125 * gst_element_get_state:
2126 * @element: a #GstElement to get the state of.
2127 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2129 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2130 * state. Can be %NULL.
2131 * @timeout: a #GstClockTime to specify the timeout for an async
2132 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2134 * Gets the state of the element.
2136 * For elements that performed an ASYNC state change, as reported by
2137 * gst_element_set_state(), this function will block up to the
2138 * specified timeout value for the state change to complete.
2139 * If the element completes the state change or goes into
2140 * an error, this function returns immediately with a return value of
2141 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2143 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2144 * returns the current and pending state immediately.
2146 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2147 * successfully changed its state but is not able to provide data yet.
2148 * This mostly happens for live sources that only produce data in
2149 * %GST_STATE_PLAYING. While the state change return is equivalent to
2150 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2151 * some sink elements might not be able to complete their state change because
2152 * an element is not producing data to complete the preroll. When setting the
2153 * element to playing, the preroll will complete and playback will start.
2155 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2156 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2157 * element is still performing a state change or
2158 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2162 GstStateChangeReturn
2163 gst_element_get_state (GstElement * element,
2164 GstState * state, GstState * pending, GstClockTime timeout)
2166 GstElementClass *oclass;
2167 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2169 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2171 oclass = GST_ELEMENT_GET_CLASS (element);
2173 if (oclass->get_state)
2174 result = (oclass->get_state) (element, state, pending, timeout);
2180 * gst_element_abort_state:
2181 * @element: a #GstElement to abort the state of.
2183 * Abort the state change of the element. This function is used
2184 * by elements that do asynchronous state changes and find out
2185 * something is wrong.
2187 * This function should be called with the STATE_LOCK held.
2192 gst_element_abort_state (GstElement * element)
2196 #ifndef GST_DISABLE_GST_DEBUG
2200 g_return_if_fail (GST_IS_ELEMENT (element));
2202 GST_OBJECT_LOCK (element);
2203 pending = GST_STATE_PENDING (element);
2205 if (pending == GST_STATE_VOID_PENDING ||
2206 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2207 goto nothing_aborted;
2209 #ifndef GST_DISABLE_GST_DEBUG
2210 old_state = GST_STATE (element);
2212 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2213 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2214 gst_element_state_get_name (pending));
2218 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2220 GST_STATE_BROADCAST (element);
2221 GST_OBJECT_UNLOCK (element);
2227 GST_OBJECT_UNLOCK (element);
2232 /* Not static because GstBin has manual state handling too */
2234 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2235 GstState newstate, GstState pending)
2237 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2238 GstMessage *message;
2240 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2241 "notifying about state-changed %s to %s (%s pending)",
2242 gst_element_state_get_name (oldstate),
2243 gst_element_state_get_name (newstate),
2244 gst_element_state_get_name (pending));
2246 if (klass->state_changed)
2247 klass->state_changed (element, oldstate, newstate, pending);
2249 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2250 oldstate, newstate, pending);
2251 gst_element_post_message (element, message);
2255 * gst_element_continue_state:
2256 * @element: a #GstElement to continue the state change of.
2257 * @ret: The previous state return value
2259 * Commit the state change of the element and proceed to the next
2260 * pending state if any. This function is used
2261 * by elements that do asynchronous state changes.
2262 * The core will normally call this method automatically when an
2263 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2265 * If after calling this method the element still has not reached
2266 * the pending state, the next state change is performed.
2268 * This method is used internally and should normally not be called by plugins
2271 * Returns: The result of the commit state change.
2275 GstStateChangeReturn
2276 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2278 GstStateChangeReturn old_ret;
2279 GstState old_state, old_next;
2280 GstState current, next, pending;
2281 GstStateChange transition;
2283 GST_OBJECT_LOCK (element);
2284 old_ret = GST_STATE_RETURN (element);
2285 GST_STATE_RETURN (element) = ret;
2286 pending = GST_STATE_PENDING (element);
2288 /* check if there is something to commit */
2289 if (pending == GST_STATE_VOID_PENDING)
2290 goto nothing_pending;
2292 old_state = GST_STATE (element);
2293 /* this is the state we should go to next */
2294 old_next = GST_STATE_NEXT (element);
2295 /* update current state */
2296 current = GST_STATE (element) = old_next;
2298 /* see if we reached the final state */
2299 if (pending == current)
2302 next = GST_STATE_GET_NEXT (current, pending);
2303 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2305 GST_STATE_NEXT (element) = next;
2307 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2308 GST_OBJECT_UNLOCK (element);
2310 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2311 "committing state from %s to %s, pending %s, next %s",
2312 gst_element_state_get_name (old_state),
2313 gst_element_state_get_name (old_next),
2314 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2316 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2318 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2319 "continue state change %s to %s, final %s",
2320 gst_element_state_get_name (current),
2321 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2323 ret = gst_element_change_state (element, transition);
2329 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2330 GST_OBJECT_UNLOCK (element);
2335 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2336 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2338 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2339 "completed state change to %s", gst_element_state_get_name (pending));
2340 GST_OBJECT_UNLOCK (element);
2342 /* don't post silly messages with the same state. This can happen
2343 * when an element state is changed to what it already was. For bins
2344 * this can be the result of a lost state, which we check with the
2345 * previous return value.
2346 * We do signal the cond though as a _get_state() might be blocking
2348 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2349 _priv_gst_element_state_changed (element, old_state, old_next,
2350 GST_STATE_VOID_PENDING);
2352 GST_STATE_BROADCAST (element);
2359 * gst_element_lost_state:
2360 * @element: a #GstElement the state is lost of
2361 * @new_base_time: if a new base time should be distributed
2363 * Brings the element to the lost state. The current state of the
2364 * element is copied to the pending state so that any call to
2365 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2367 * An ASYNC_START message is posted with indication to distribute a new
2368 * base_time to the element when @new_base_time is %TRUE.
2369 * If the element was PLAYING, it will go to PAUSED. The element
2370 * will be restored to its PLAYING state by the parent pipeline when it
2373 * This is mostly used for elements that lost their preroll buffer
2374 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2375 * they will go to their pending state again when a new preroll buffer is
2376 * queued. This function can only be called when the element is currently
2377 * not in error or an async state change.
2379 * This function is used internally and should normally not be called from
2380 * plugins or applications.
2383 gst_element_lost_state (GstElement * element, gboolean new_base_time)
2385 GstState old_state, new_state;
2386 GstMessage *message;
2388 g_return_if_fail (GST_IS_ELEMENT (element));
2390 GST_OBJECT_LOCK (element);
2391 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2394 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2395 goto only_async_start;
2397 old_state = GST_STATE (element);
2399 /* when we were PLAYING, the new state is PAUSED. We will also not
2400 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2401 * when we preroll. */
2402 if (old_state > GST_STATE_PAUSED)
2403 new_state = GST_STATE_PAUSED;
2405 new_state = old_state;
2407 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2408 "lost state of %s to %s", gst_element_state_get_name (old_state),
2409 gst_element_state_get_name (new_state));
2411 GST_STATE (element) = new_state;
2412 GST_STATE_NEXT (element) = new_state;
2413 GST_STATE_PENDING (element) = new_state;
2414 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2416 GST_ELEMENT_START_TIME (element) = 0;
2417 GST_OBJECT_UNLOCK (element);
2419 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2422 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2423 gst_element_post_message (element, message);
2429 GST_OBJECT_UNLOCK (element);
2434 GST_OBJECT_UNLOCK (element);
2436 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2437 gst_element_post_message (element, message);
2443 * gst_element_set_state:
2444 * @element: a #GstElement to change state of.
2445 * @state: the element's new #GstState.
2447 * Sets the state of the element. This function will try to set the
2448 * requested state by going through all the intermediary states and calling
2449 * the class's state change function for each.
2451 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2452 * element will perform the remainder of the state change asynchronously in
2454 * An application can use gst_element_get_state() to wait for the completion
2455 * of the state change or it can wait for a state change message on the bus.
2457 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2458 * #GST_STATE_CHANGE_ASYNC.
2460 * Returns: Result of the state change using #GstStateChangeReturn.
2464 GstStateChangeReturn
2465 gst_element_set_state (GstElement * element, GstState state)
2467 GstElementClass *oclass;
2468 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2470 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2472 oclass = GST_ELEMENT_GET_CLASS (element);
2474 if (oclass->set_state)
2475 result = (oclass->set_state) (element, state);
2481 * default set state function, calculates the next state based
2482 * on current state and calls the change_state function
2484 static GstStateChangeReturn
2485 gst_element_set_state_func (GstElement * element, GstState state)
2487 GstState current, next, old_pending;
2488 GstStateChangeReturn ret;
2489 GstStateChange transition;
2490 GstStateChangeReturn old_ret;
2492 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2494 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2495 gst_element_state_get_name (state));
2497 /* state lock is taken to protect the set_state() and get_state()
2498 * procedures, it does not lock any variables. */
2499 GST_STATE_LOCK (element);
2501 /* now calculate how to get to the new state */
2502 GST_OBJECT_LOCK (element);
2503 old_ret = GST_STATE_RETURN (element);
2504 /* previous state change returned an error, remove all pending
2505 * and next states */
2506 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2507 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2508 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2509 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2512 current = GST_STATE (element);
2513 next = GST_STATE_NEXT (element);
2514 old_pending = GST_STATE_PENDING (element);
2516 /* this is the (new) state we should go to. TARGET is the last state we set on
2518 if (state != GST_STATE_TARGET (element)) {
2519 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2520 "setting target state to %s", gst_element_state_get_name (state));
2521 GST_STATE_TARGET (element) = state;
2522 /* increment state cookie so that we can track each state change. We only do
2523 * this if this is actually a new state change. */
2524 element->state_cookie++;
2526 GST_STATE_PENDING (element) = state;
2528 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2529 "current %s, old_pending %s, next %s, old return %s",
2530 gst_element_state_get_name (current),
2531 gst_element_state_get_name (old_pending),
2532 gst_element_state_get_name (next),
2533 gst_element_state_change_return_get_name (old_ret));
2535 /* if the element was busy doing a state change, we just update the
2536 * target state, it'll get to it async then. */
2537 if (old_pending != GST_STATE_VOID_PENDING) {
2538 /* upwards state change will happen ASYNC */
2539 if (old_pending <= state)
2541 /* element is going to this state already */
2542 else if (next == state)
2544 /* element was performing an ASYNC upward state change and
2545 * we request to go downward again. Start from the next pending
2547 else if (next > state
2548 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2552 next = GST_STATE_GET_NEXT (current, state);
2553 /* now we store the next state */
2554 GST_STATE_NEXT (element) = next;
2555 /* mark busy, we need to check that there is actually a state change
2556 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2557 * the default element change_state function has no way to know what the
2558 * old value was... could consider this a FIXME...*/
2559 if (current != next)
2560 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2562 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2564 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2565 "%s: setting state from %s to %s",
2566 (next != state ? "intermediate" : "final"),
2567 gst_element_state_get_name (current), gst_element_state_get_name (next));
2569 /* now signal any waiters, they will error since the cookie was incremented */
2570 GST_STATE_BROADCAST (element);
2572 GST_OBJECT_UNLOCK (element);
2574 ret = gst_element_change_state (element, transition);
2576 GST_STATE_UNLOCK (element);
2578 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2579 gst_element_state_change_return_get_name (ret));
2585 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2586 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2587 "element was busy with async state change");
2588 GST_OBJECT_UNLOCK (element);
2590 GST_STATE_UNLOCK (element);
2592 return GST_STATE_CHANGE_ASYNC;
2597 * gst_element_change_state:
2598 * @element: a #GstElement
2599 * @transition: the requested transition
2601 * Perform @transition on @element.
2603 * This function must be called with STATE_LOCK held and is mainly used
2606 * Returns: the #GstStateChangeReturn of the state transition.
2608 GstStateChangeReturn
2609 gst_element_change_state (GstElement * element, GstStateChange transition)
2611 GstElementClass *oclass;
2612 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2614 oclass = GST_ELEMENT_GET_CLASS (element);
2616 /* call the state change function so it can set the state */
2617 if (oclass->change_state)
2618 ret = (oclass->change_state) (element, transition);
2620 ret = GST_STATE_CHANGE_FAILURE;
2623 case GST_STATE_CHANGE_FAILURE:
2624 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2625 "have FAILURE change_state return");
2626 /* state change failure */
2627 gst_element_abort_state (element);
2629 case GST_STATE_CHANGE_ASYNC:
2633 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2634 "element will change state ASYNC");
2636 target = GST_STATE_TARGET (element);
2638 if (target > GST_STATE_READY)
2641 /* else we just continue the state change downwards */
2642 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2643 "forcing commit state %s <= %s",
2644 gst_element_state_get_name (target),
2645 gst_element_state_get_name (GST_STATE_READY));
2647 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2650 case GST_STATE_CHANGE_SUCCESS:
2651 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2652 "element changed state SUCCESS");
2653 /* we can commit the state now which will proceeed to
2655 ret = gst_element_continue_state (element, ret);
2657 case GST_STATE_CHANGE_NO_PREROLL:
2658 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2659 "element changed state NO_PREROLL");
2660 /* we can commit the state now which will proceeed to
2662 ret = gst_element_continue_state (element, ret);
2665 goto invalid_return;
2668 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2673 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2681 GST_OBJECT_LOCK (element);
2682 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2683 g_critical ("%s: unknown return value %d from a state change function",
2684 GST_ELEMENT_NAME (element), ret);
2686 /* we are in error now */
2687 ret = GST_STATE_CHANGE_FAILURE;
2688 GST_STATE_RETURN (element) = ret;
2689 GST_OBJECT_UNLOCK (element);
2695 /* gst_iterator_fold functions for pads_activate
2696 * Stop the iterator if activating one pad failed. */
2698 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2700 GstPad *pad = g_value_get_object (vpad);
2701 gboolean cont = TRUE;
2703 if (!(cont = gst_pad_set_active (pad, *active)))
2704 g_value_set_boolean (ret, FALSE);
2709 /* returns false on error or early cutout of the fold, true if all
2710 * pads in @iter were (de)activated successfully. */
2712 iterator_activate_fold_with_resync (GstIterator * iter,
2713 GstIteratorFoldFunction func, gpointer user_data)
2715 GstIteratorResult ires;
2718 /* no need to unset this later, it's just a boolean */
2719 g_value_init (&ret, G_TYPE_BOOLEAN);
2720 g_value_set_boolean (&ret, TRUE);
2723 ires = gst_iterator_fold (iter, func, &ret, user_data);
2725 case GST_ITERATOR_RESYNC:
2726 /* need to reset the result again */
2727 g_value_set_boolean (&ret, TRUE);
2728 gst_iterator_resync (iter);
2730 case GST_ITERATOR_DONE:
2731 /* all pads iterated, return collected value */
2734 /* iterator returned _ERROR or premature end with _OK,
2735 * mark an error and exit */
2736 g_value_set_boolean (&ret, FALSE);
2741 /* return collected value */
2742 return g_value_get_boolean (&ret);
2745 /* is called with STATE_LOCK
2747 * Pads are activated from source pads to sinkpads.
2750 gst_element_pads_activate (GstElement * element, gboolean active)
2755 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2756 "pads_activate with active %d", active);
2758 iter = gst_element_iterate_src_pads (element);
2760 iterator_activate_fold_with_resync (iter,
2761 (GstIteratorFoldFunction) activate_pads, &active);
2762 gst_iterator_free (iter);
2763 if (G_UNLIKELY (!res))
2766 iter = gst_element_iterate_sink_pads (element);
2768 iterator_activate_fold_with_resync (iter,
2769 (GstIteratorFoldFunction) activate_pads, &active);
2770 gst_iterator_free (iter);
2771 if (G_UNLIKELY (!res))
2774 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2775 "pads_activate successful");
2782 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2783 "source pads_activate failed");
2788 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2789 "sink pads_activate failed");
2794 /* is called with STATE_LOCK */
2795 static GstStateChangeReturn
2796 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2798 GstState state, next;
2799 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2801 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2803 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2804 next = GST_STATE_TRANSITION_NEXT (transition);
2806 /* if the element already is in the given state, we just return success */
2807 if (next == GST_STATE_VOID_PENDING || state == next)
2810 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2811 "default handler tries setting state from %s to %s (%04x)",
2812 gst_element_state_get_name (state),
2813 gst_element_state_get_name (next), transition);
2815 switch (transition) {
2816 case GST_STATE_CHANGE_NULL_TO_READY:
2818 case GST_STATE_CHANGE_READY_TO_PAUSED:
2819 if (!gst_element_pads_activate (element, TRUE)) {
2820 result = GST_STATE_CHANGE_FAILURE;
2823 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2825 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2827 case GST_STATE_CHANGE_PAUSED_TO_READY:
2828 case GST_STATE_CHANGE_READY_TO_NULL:
2829 /* deactivate pads in both cases, since they are activated on
2830 ready->paused but the element might not have made it to paused */
2831 if (!gst_element_pads_activate (element, FALSE)) {
2832 result = GST_STATE_CHANGE_FAILURE;
2836 /* this will catch real but unhandled state changes;
2837 * can only be caused by:
2838 * - a new state was added
2839 * - somehow the element was asked to jump across an intermediate state
2841 g_warning ("Unhandled state change from %s to %s",
2842 gst_element_state_get_name (state),
2843 gst_element_state_get_name (next));
2850 GST_OBJECT_LOCK (element);
2851 result = GST_STATE_RETURN (element);
2852 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2853 "element is already in the %s state",
2854 gst_element_state_get_name (state));
2855 GST_OBJECT_UNLOCK (element);
2862 * gst_element_get_factory:
2863 * @element: a #GstElement to request the element factory of.
2865 * Retrieves the factory that was used to create this element.
2867 * Returns: (transfer none): the #GstElementFactory used for creating this
2868 * element. no refcounting is needed.
2871 gst_element_get_factory (GstElement * element)
2873 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2875 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2879 gst_element_dispose (GObject * object)
2881 GstElement *element = GST_ELEMENT_CAST (object);
2885 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2887 if (GST_STATE (element) != GST_STATE_NULL)
2890 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2891 "removing %d pads", g_list_length (element->pads));
2892 /* first we break all our links with the outside */
2893 while (element->pads && element->pads->data) {
2894 /* don't call _remove_pad with NULL */
2895 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2897 if (G_UNLIKELY (element->pads != NULL)) {
2898 g_critical ("could not remove pads from element %s",
2899 GST_STR_NULL (GST_OBJECT_NAME (object)));
2902 GST_OBJECT_LOCK (element);
2903 clock_p = &element->clock;
2904 bus_p = &element->bus;
2905 gst_object_replace ((GstObject **) clock_p, NULL);
2906 gst_object_replace ((GstObject **) bus_p, NULL);
2907 GST_OBJECT_UNLOCK (element);
2909 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2911 G_OBJECT_CLASS (parent_class)->dispose (object);
2920 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2922 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2924 "You need to explicitly set elements to the NULL state before\n"
2925 "dropping the final reference, to allow them to clean up.\n"
2926 "This problem may also be caused by a refcounting bug in the\n"
2927 "application or some element.\n",
2928 GST_OBJECT_NAME (element),
2929 gst_element_state_get_name (GST_STATE (element)),
2930 is_locked ? " (locked)" : "");
2936 gst_element_finalize (GObject * object)
2938 GstElement *element = GST_ELEMENT_CAST (object);
2940 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2942 GST_STATE_LOCK (element);
2943 if (element->state_cond)
2944 g_cond_free (element->state_cond);
2945 element->state_cond = NULL;
2946 GST_STATE_UNLOCK (element);
2947 g_static_rec_mutex_free (element->state_lock);
2948 g_slice_free (GStaticRecMutex, element->state_lock);
2949 element->state_lock = NULL;
2951 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2953 G_OBJECT_CLASS (parent_class)->finalize (object);
2957 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2961 g_return_if_fail (GST_IS_ELEMENT (element));
2963 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2965 GST_OBJECT_LOCK (element);
2966 bus_p = &GST_ELEMENT_BUS (element);
2967 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2968 GST_OBJECT_UNLOCK (element);
2972 * gst_element_set_bus:
2973 * @element: a #GstElement to set the bus of.
2974 * @bus: (transfer none): the #GstBus to set.
2976 * Sets the bus of the element. Increases the refcount on the bus.
2977 * For internal use only, unless you're testing elements.
2982 gst_element_set_bus (GstElement * element, GstBus * bus)
2984 GstElementClass *oclass;
2986 g_return_if_fail (GST_IS_ELEMENT (element));
2988 oclass = GST_ELEMENT_GET_CLASS (element);
2990 if (oclass->set_bus)
2991 oclass->set_bus (element, bus);
2995 * gst_element_get_bus:
2996 * @element: a #GstElement to get the bus of.
2998 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2999 * bus for the application.
3001 * Returns: (transfer full): the element's #GstBus. unref after usage.
3006 gst_element_get_bus (GstElement * element)
3008 GstBus *result = NULL;
3010 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3012 GST_OBJECT_LOCK (element);
3013 if ((result = GST_ELEMENT_BUS (element)))
3014 gst_object_ref (result);
3015 GST_OBJECT_UNLOCK (element);
3017 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,