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 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1301 klass->numpadtemplates++;
1305 * gst_element_class_add_metadata:
1306 * @klass: class to set metadata for
1307 * @key: the key to set
1308 * @value: the value to set
1310 * Set @key with @value as metadata in @klass.
1313 gst_element_class_add_metadata (GstElementClass * klass,
1314 const gchar * key, const gchar * value)
1316 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1317 g_return_if_fail (key != NULL);
1318 g_return_if_fail (value != NULL);
1320 gst_structure_set ((GstStructure *) klass->metadata,
1321 key, G_TYPE_STRING, value, NULL);
1325 * gst_element_class_set_metadata:
1326 * @klass: class to set metadata for
1327 * @longname: The long English name of the element. E.g. "File Sink"
1328 * @classification: String describing the type of element, as an unordered list
1329 * separated with slashes ('/'). See draft-klass.txt of the design docs
1330 * for more details and common types. E.g: "Sink/File"
1331 * @description: Sentence describing the purpose of the element.
1332 * E.g: "Write stream to a file"
1333 * @author: Name and contact details of the author(s). Use \n to separate
1334 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1336 * Sets the detailed information for a #GstElementClass.
1337 * <note>This function is for use in _class_init functions only.</note>
1340 gst_element_class_set_metadata (GstElementClass * klass,
1341 const gchar * longname, const gchar * classification,
1342 const gchar * description, const gchar * author)
1344 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1346 gst_structure_set ((GstStructure *) klass->metadata,
1347 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1348 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1349 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1350 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1354 * gst_element_class_get_pad_template_list:
1355 * @element_class: a #GstElementClass to get pad templates of.
1357 * Retrieves a list of the pad templates associated with @element_class. The
1358 * list must not be modified by the calling code.
1359 * <note>If you use this function in the #GInstanceInitFunc of an object class
1360 * that has subclasses, make sure to pass the g_class parameter of the
1361 * #GInstanceInitFunc here.</note>
1363 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1367 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1369 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1371 return element_class->padtemplates;
1375 * gst_element_class_get_pad_template:
1376 * @element_class: a #GstElementClass to get the pad template of.
1377 * @name: the name of the #GstPadTemplate to get.
1379 * Retrieves a padtemplate from @element_class with the given name.
1380 * <note>If you use this function in the #GInstanceInitFunc of an object class
1381 * that has subclasses, make sure to pass the g_class parameter of the
1382 * #GInstanceInitFunc here.</note>
1384 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1385 * if none was found. No unreferencing is necessary.
1388 gst_element_class_get_pad_template (GstElementClass *
1389 element_class, const gchar * name)
1393 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1394 g_return_val_if_fail (name != NULL, NULL);
1396 padlist = element_class->padtemplates;
1399 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1401 if (strcmp (padtempl->name_template, name) == 0)
1404 padlist = g_list_next (padlist);
1410 static GstPadTemplate *
1411 gst_element_class_get_request_pad_template (GstElementClass *
1412 element_class, const gchar * name)
1414 GstPadTemplate *tmpl;
1416 tmpl = gst_element_class_get_pad_template (element_class, name);
1417 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1423 /* get a random pad on element of the given direction.
1424 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1427 gst_element_get_random_pad (GstElement * element,
1428 gboolean need_linked, GstPadDirection dir)
1430 GstPad *result = NULL;
1433 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1437 GST_OBJECT_LOCK (element);
1438 pads = element->srcpads;
1441 GST_OBJECT_LOCK (element);
1442 pads = element->sinkpads;
1445 goto wrong_direction;
1447 for (; pads; pads = g_list_next (pads)) {
1448 GstPad *pad = GST_PAD_CAST (pads->data);
1450 GST_OBJECT_LOCK (pad);
1451 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1452 GST_DEBUG_PAD_NAME (pad));
1454 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1455 /* if we require a linked pad, and it is not linked, continue the
1457 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1458 GST_DEBUG_PAD_NAME (pad));
1459 GST_OBJECT_UNLOCK (pad);
1462 /* found a pad, stop search */
1463 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1464 GST_DEBUG_PAD_NAME (pad));
1465 GST_OBJECT_UNLOCK (pad);
1471 gst_object_ref (result);
1473 GST_OBJECT_UNLOCK (element);
1477 /* ERROR handling */
1480 g_warning ("unknown pad direction %d", dir);
1486 gst_element_default_send_event (GstElement * element, GstEvent * event)
1488 gboolean result = FALSE;
1491 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1492 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1493 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1496 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1497 "pushing %s event to random %s pad %s:%s",
1498 GST_EVENT_TYPE_NAME (event),
1499 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1500 GST_DEBUG_PAD_NAME (pad));
1502 result = gst_pad_push_event (pad, event);
1503 gst_object_unref (pad);
1505 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1506 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1507 gst_event_unref (event);
1513 * gst_element_send_event:
1514 * @element: a #GstElement to send the event to.
1515 * @event: (transfer full): the #GstEvent to send to the element.
1517 * Sends an event to an element. If the element doesn't implement an
1518 * event handler, the event will be pushed on a random linked sink pad for
1519 * upstream events or a random linked source pad for downstream events.
1521 * This function takes owership of the provided event so you should
1522 * gst_event_ref() it if you want to reuse the event after this call.
1524 * Returns: %TRUE if the event was handled.
1529 gst_element_send_event (GstElement * element, GstEvent * event)
1531 GstElementClass *oclass;
1532 gboolean result = FALSE;
1534 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1535 g_return_val_if_fail (event != NULL, FALSE);
1537 oclass = GST_ELEMENT_GET_CLASS (element);
1539 GST_STATE_LOCK (element);
1540 if (oclass->send_event) {
1541 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1542 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1543 result = oclass->send_event (element, event);
1545 result = gst_element_default_send_event (element, event);
1547 GST_STATE_UNLOCK (element);
1554 * @element: a #GstElement to send the event to.
1555 * @rate: The new playback rate
1556 * @format: The format of the seek values
1557 * @flags: The optional seek flags.
1558 * @cur_type: The type and flags for the new current position
1559 * @cur: The value of the new current position
1560 * @stop_type: The type and flags for the new stop position
1561 * @stop: The value of the new stop position
1563 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1564 * the parameters. The seek event is sent to the element using
1565 * gst_element_send_event().
1567 * Returns: %TRUE if the event was handled.
1572 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1573 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1574 GstSeekType stop_type, gint64 stop)
1579 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1582 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1583 result = gst_element_send_event (element, event);
1589 * gst_element_get_query_types:
1590 * @element: a #GstElement to query
1592 * Get an array of query types from the element.
1593 * If the element doesn't implement a query types function,
1594 * the query will be forwarded to the peer of a random linked sink pad.
1596 * Returns: An array of #GstQueryType elements that should not
1597 * be freed or modified.
1601 const GstQueryType *
1602 gst_element_get_query_types (GstElement * element)
1604 GstElementClass *oclass;
1605 const GstQueryType *result = NULL;
1607 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1609 oclass = GST_ELEMENT_GET_CLASS (element);
1611 if (oclass->get_query_types) {
1612 result = oclass->get_query_types (element);
1614 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1617 GstPad *peer = gst_pad_get_peer (pad);
1620 result = gst_pad_get_query_types (peer);
1622 gst_object_unref (peer);
1624 gst_object_unref (pad);
1631 gst_element_default_query (GstElement * element, GstQuery ** query)
1633 gboolean result = FALSE;
1636 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1638 result = gst_pad_query (pad, query);
1640 gst_object_unref (pad);
1642 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1644 GstPad *peer = gst_pad_get_peer (pad);
1647 result = gst_pad_query (peer, query);
1649 gst_object_unref (peer);
1651 gst_object_unref (pad);
1658 * gst_element_query:
1659 * @element: a #GstElement to perform the query on.
1660 * @query: (transfer none): the #GstQuery.
1662 * Performs a query on the given element.
1664 * For elements that don't implement a query handler, this function
1665 * forwards the query to a random srcpad or to the peer of a
1666 * random linked sinkpad of this element.
1668 * Please note that some queries might need a running pipeline to work.
1670 * Returns: TRUE if the query could be performed.
1675 gst_element_query (GstElement * element, GstQuery ** query)
1677 GstElementClass *oclass;
1678 gboolean result = FALSE;
1680 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1681 g_return_val_if_fail (query != NULL, FALSE);
1682 g_return_val_if_fail (GST_IS_QUERY (*query), FALSE);
1684 oclass = GST_ELEMENT_GET_CLASS (element);
1686 if (oclass->query) {
1687 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1688 GST_ELEMENT_NAME (element));
1689 result = oclass->query (element, query);
1691 result = gst_element_default_query (element, query);
1697 * gst_element_post_message:
1698 * @element: a #GstElement posting the message
1699 * @message: (transfer full): a #GstMessage to post
1701 * Post a message on the element's #GstBus. This function takes ownership of the
1702 * message; if you want to access the message after this call, you should add an
1703 * additional reference before calling.
1705 * Returns: %TRUE if the message was successfully posted. The function returns
1706 * %FALSE if the element did not have a bus.
1711 gst_element_post_message (GstElement * element, GstMessage * message)
1714 gboolean result = FALSE;
1716 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1717 g_return_val_if_fail (message != NULL, FALSE);
1719 GST_OBJECT_LOCK (element);
1722 if (G_UNLIKELY (bus == NULL))
1725 gst_object_ref (bus);
1726 GST_OBJECT_UNLOCK (element);
1728 /* we release the element lock when posting the message so that any
1729 * (synchronous) message handlers can operate on the element */
1730 result = gst_bus_post (bus, message);
1731 gst_object_unref (bus);
1738 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1739 "not posting message %p: no bus", message);
1740 GST_OBJECT_UNLOCK (element);
1741 gst_message_unref (message);
1747 * _gst_element_error_printf:
1748 * @format: the printf-like format to use, or %NULL
1750 * This function is only used internally by the gst_element_error() macro.
1752 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1758 _gst_element_error_printf (const gchar * format, ...)
1768 va_start (args, format);
1769 buffer = g_strdup_vprintf (format, args);
1775 * gst_element_message_full:
1776 * @element: a #GstElement to send message from
1777 * @type: the #GstMessageType
1778 * @domain: the GStreamer GError domain this message belongs to
1779 * @code: the GError code belonging to the domain
1780 * @text: (allow-none) (transfer full): an allocated text string to be used
1781 * as a replacement for the default message connected to code,
1783 * @debug: (allow-none) (transfer full): an allocated debug message to be
1784 * used as a replacement for the default debugging information,
1786 * @file: the source code file where the error was generated
1787 * @function: the source code function where the error was generated
1788 * @line: the source code line where the error was generated
1790 * Post an error, warning or info message on the bus from inside an element.
1792 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1793 * #GST_MESSAGE_INFO.
1797 void gst_element_message_full
1798 (GstElement * element, GstMessageType type,
1799 GQuark domain, gint code, gchar * text,
1800 gchar * debug, const gchar * file, const gchar * function, gint line)
1802 GError *gerror = NULL;
1806 gboolean has_debug = TRUE;
1807 GstMessage *message = NULL;
1810 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1811 g_return_if_fail (GST_IS_ELEMENT (element));
1812 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1813 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1815 /* check if we send the given text or the default error text */
1816 if ((text == NULL) || (text[0] == 0)) {
1817 /* text could have come from g_strdup_printf (""); */
1819 sent_text = gst_error_get_message (domain, code);
1823 /* construct a sent_debug with extra information from source */
1824 if ((debug == NULL) || (debug[0] == 0)) {
1825 /* debug could have come from g_strdup_printf (""); */
1829 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1831 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1832 file, line, function, name, debug);
1834 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1835 file, line, function, name);
1839 /* create gerror and post message */
1840 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1842 gerror = g_error_new_literal (domain, code, sent_text);
1845 case GST_MESSAGE_ERROR:
1847 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1849 case GST_MESSAGE_WARNING:
1850 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1853 case GST_MESSAGE_INFO:
1854 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1858 g_assert_not_reached ();
1861 gst_element_post_message (element, message);
1863 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1864 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1867 g_error_free (gerror);
1868 g_free (sent_debug);
1873 * gst_element_is_locked_state:
1874 * @element: a #GstElement.
1876 * Checks if the state of an element is locked.
1877 * If the state of an element is locked, state changes of the parent don't
1878 * affect the element.
1879 * This way you can leave currently unused elements inside bins. Just lock their
1880 * state before changing the state from #GST_STATE_NULL.
1884 * Returns: TRUE, if the element's state is locked.
1887 gst_element_is_locked_state (GstElement * element)
1891 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1893 GST_OBJECT_LOCK (element);
1894 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1895 GST_OBJECT_UNLOCK (element);
1901 * gst_element_set_locked_state:
1902 * @element: a #GstElement
1903 * @locked_state: TRUE to lock the element's state
1905 * Locks the state of an element, so state changes of the parent don't affect
1906 * this element anymore.
1910 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1911 * or the elements state-locking needed no change.
1914 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1918 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1920 GST_OBJECT_LOCK (element);
1921 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1923 if (G_UNLIKELY (old == locked_state))
1927 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1928 GST_ELEMENT_NAME (element));
1929 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1931 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1932 GST_ELEMENT_NAME (element));
1933 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1935 GST_OBJECT_UNLOCK (element);
1941 GST_CAT_DEBUG (GST_CAT_STATES,
1942 "elements %s was already in locked state %d",
1943 GST_ELEMENT_NAME (element), old);
1944 GST_OBJECT_UNLOCK (element);
1951 * gst_element_sync_state_with_parent:
1952 * @element: a #GstElement.
1954 * Tries to change the state of the element to the same as its parent.
1955 * If this function returns FALSE, the state of element is undefined.
1957 * Returns: TRUE, if the element's state could be synced to the parent's state.
1962 gst_element_sync_state_with_parent (GstElement * element)
1966 GstStateChangeReturn ret;
1968 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1970 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1971 GstState parent_current, parent_pending;
1973 GST_OBJECT_LOCK (parent);
1974 parent_current = GST_STATE (parent);
1975 parent_pending = GST_STATE_PENDING (parent);
1976 GST_OBJECT_UNLOCK (parent);
1978 /* set to pending if there is one, else we set it to the current state of
1980 if (parent_pending != GST_STATE_VOID_PENDING)
1981 target = parent_pending;
1983 target = parent_current;
1985 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1986 "syncing state (%s) to parent %s %s (%s, %s)",
1987 gst_element_state_get_name (GST_STATE (element)),
1988 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1989 gst_element_state_get_name (parent_current),
1990 gst_element_state_get_name (parent_pending));
1992 ret = gst_element_set_state (element, target);
1993 if (ret == GST_STATE_CHANGE_FAILURE)
1996 gst_object_unref (parent);
2000 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2007 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2008 "syncing state failed (%s)",
2009 gst_element_state_change_return_get_name (ret));
2010 gst_object_unref (parent);
2016 static GstStateChangeReturn
2017 gst_element_get_state_func (GstElement * element,
2018 GstState * state, GstState * pending, GstClockTime timeout)
2020 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2021 GstState old_pending;
2023 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2024 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2026 GST_OBJECT_LOCK (element);
2027 ret = GST_STATE_RETURN (element);
2028 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2029 gst_element_state_change_return_get_name (ret));
2031 /* we got an error, report immediately */
2032 if (ret == GST_STATE_CHANGE_FAILURE)
2035 /* we got no_preroll, report immediatly */
2036 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2039 /* no need to wait async if we are not async */
2040 if (ret != GST_STATE_CHANGE_ASYNC)
2043 old_pending = GST_STATE_PENDING (element);
2044 if (old_pending != GST_STATE_VOID_PENDING) {
2045 GTimeVal *timeval, abstimeout;
2048 if (timeout != GST_CLOCK_TIME_NONE) {
2049 glong add = timeout / 1000;
2054 /* make timeout absolute */
2055 g_get_current_time (&abstimeout);
2056 g_time_val_add (&abstimeout, add);
2057 timeval = &abstimeout;
2061 /* get cookie to detect state changes during waiting */
2062 cookie = element->state_cookie;
2064 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2065 "waiting for element to commit state");
2067 /* we have a pending state change, wait for it to complete */
2068 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2069 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2070 /* timeout triggered */
2071 ret = GST_STATE_CHANGE_ASYNC;
2073 if (cookie != element->state_cookie)
2076 /* could be success or failure */
2077 if (old_pending == GST_STATE (element)) {
2078 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2079 ret = GST_STATE_CHANGE_SUCCESS;
2081 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2082 ret = GST_STATE_CHANGE_FAILURE;
2085 /* if nothing is pending anymore we can return SUCCESS */
2086 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2087 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2088 ret = GST_STATE_CHANGE_SUCCESS;
2094 *state = GST_STATE (element);
2096 *pending = GST_STATE_PENDING (element);
2098 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2099 "state current: %s, pending: %s, result: %s",
2100 gst_element_state_get_name (GST_STATE (element)),
2101 gst_element_state_get_name (GST_STATE_PENDING (element)),
2102 gst_element_state_change_return_get_name (ret));
2103 GST_OBJECT_UNLOCK (element);
2110 *state = GST_STATE_VOID_PENDING;
2112 *pending = GST_STATE_VOID_PENDING;
2114 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2116 GST_OBJECT_UNLOCK (element);
2118 return GST_STATE_CHANGE_FAILURE;
2123 * gst_element_get_state:
2124 * @element: a #GstElement to get the state of.
2125 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2127 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2128 * state. Can be %NULL.
2129 * @timeout: a #GstClockTime to specify the timeout for an async
2130 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2132 * Gets the state of the element.
2134 * For elements that performed an ASYNC state change, as reported by
2135 * gst_element_set_state(), this function will block up to the
2136 * specified timeout value for the state change to complete.
2137 * If the element completes the state change or goes into
2138 * an error, this function returns immediately with a return value of
2139 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2141 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2142 * returns the current and pending state immediately.
2144 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2145 * successfully changed its state but is not able to provide data yet.
2146 * This mostly happens for live sources that only produce data in
2147 * %GST_STATE_PLAYING. While the state change return is equivalent to
2148 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2149 * some sink elements might not be able to complete their state change because
2150 * an element is not producing data to complete the preroll. When setting the
2151 * element to playing, the preroll will complete and playback will start.
2153 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2154 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2155 * element is still performing a state change or
2156 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2160 GstStateChangeReturn
2161 gst_element_get_state (GstElement * element,
2162 GstState * state, GstState * pending, GstClockTime timeout)
2164 GstElementClass *oclass;
2165 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2167 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2169 oclass = GST_ELEMENT_GET_CLASS (element);
2171 if (oclass->get_state)
2172 result = (oclass->get_state) (element, state, pending, timeout);
2178 * gst_element_abort_state:
2179 * @element: a #GstElement to abort the state of.
2181 * Abort the state change of the element. This function is used
2182 * by elements that do asynchronous state changes and find out
2183 * something is wrong.
2185 * This function should be called with the STATE_LOCK held.
2190 gst_element_abort_state (GstElement * element)
2194 #ifndef GST_DISABLE_GST_DEBUG
2198 g_return_if_fail (GST_IS_ELEMENT (element));
2200 GST_OBJECT_LOCK (element);
2201 pending = GST_STATE_PENDING (element);
2203 if (pending == GST_STATE_VOID_PENDING ||
2204 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2205 goto nothing_aborted;
2207 #ifndef GST_DISABLE_GST_DEBUG
2208 old_state = GST_STATE (element);
2210 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2211 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2212 gst_element_state_get_name (pending));
2216 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2218 GST_STATE_BROADCAST (element);
2219 GST_OBJECT_UNLOCK (element);
2225 GST_OBJECT_UNLOCK (element);
2230 /* Not static because GstBin has manual state handling too */
2232 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2233 GstState newstate, GstState pending)
2235 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2236 GstMessage *message;
2238 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2239 "notifying about state-changed %s to %s (%s pending)",
2240 gst_element_state_get_name (oldstate),
2241 gst_element_state_get_name (newstate),
2242 gst_element_state_get_name (pending));
2244 if (klass->state_changed)
2245 klass->state_changed (element, oldstate, newstate, pending);
2247 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2248 oldstate, newstate, pending);
2249 gst_element_post_message (element, message);
2253 * gst_element_continue_state:
2254 * @element: a #GstElement to continue the state change of.
2255 * @ret: The previous state return value
2257 * Commit the state change of the element and proceed to the next
2258 * pending state if any. This function is used
2259 * by elements that do asynchronous state changes.
2260 * The core will normally call this method automatically when an
2261 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2263 * If after calling this method the element still has not reached
2264 * the pending state, the next state change is performed.
2266 * This method is used internally and should normally not be called by plugins
2269 * Returns: The result of the commit state change.
2273 GstStateChangeReturn
2274 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2276 GstStateChangeReturn old_ret;
2277 GstState old_state, old_next;
2278 GstState current, next, pending;
2279 GstStateChange transition;
2281 GST_OBJECT_LOCK (element);
2282 old_ret = GST_STATE_RETURN (element);
2283 GST_STATE_RETURN (element) = ret;
2284 pending = GST_STATE_PENDING (element);
2286 /* check if there is something to commit */
2287 if (pending == GST_STATE_VOID_PENDING)
2288 goto nothing_pending;
2290 old_state = GST_STATE (element);
2291 /* this is the state we should go to next */
2292 old_next = GST_STATE_NEXT (element);
2293 /* update current state */
2294 current = GST_STATE (element) = old_next;
2296 /* see if we reached the final state */
2297 if (pending == current)
2300 next = GST_STATE_GET_NEXT (current, pending);
2301 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2303 GST_STATE_NEXT (element) = next;
2305 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2306 GST_OBJECT_UNLOCK (element);
2308 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2309 "committing state from %s to %s, pending %s, next %s",
2310 gst_element_state_get_name (old_state),
2311 gst_element_state_get_name (old_next),
2312 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2314 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2316 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2317 "continue state change %s to %s, final %s",
2318 gst_element_state_get_name (current),
2319 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2321 ret = gst_element_change_state (element, transition);
2327 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2328 GST_OBJECT_UNLOCK (element);
2333 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2334 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2336 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2337 "completed state change to %s", gst_element_state_get_name (pending));
2338 GST_OBJECT_UNLOCK (element);
2340 /* don't post silly messages with the same state. This can happen
2341 * when an element state is changed to what it already was. For bins
2342 * this can be the result of a lost state, which we check with the
2343 * previous return value.
2344 * We do signal the cond though as a _get_state() might be blocking
2346 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2347 _priv_gst_element_state_changed (element, old_state, old_next,
2348 GST_STATE_VOID_PENDING);
2350 GST_STATE_BROADCAST (element);
2357 * gst_element_lost_state:
2358 * @element: a #GstElement the state is lost of
2359 * @new_base_time: if a new base time should be distributed
2361 * Brings the element to the lost state. The current state of the
2362 * element is copied to the pending state so that any call to
2363 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2365 * An ASYNC_START message is posted with indication to distribute a new
2366 * base_time to the element when @new_base_time is %TRUE.
2367 * If the element was PLAYING, it will go to PAUSED. The element
2368 * will be restored to its PLAYING state by the parent pipeline when it
2371 * This is mostly used for elements that lost their preroll buffer
2372 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2373 * they will go to their pending state again when a new preroll buffer is
2374 * queued. This function can only be called when the element is currently
2375 * not in error or an async state change.
2377 * This function is used internally and should normally not be called from
2378 * plugins or applications.
2381 gst_element_lost_state (GstElement * element, gboolean new_base_time)
2383 GstState old_state, new_state;
2384 GstMessage *message;
2386 g_return_if_fail (GST_IS_ELEMENT (element));
2388 GST_OBJECT_LOCK (element);
2389 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2392 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2393 goto only_async_start;
2395 old_state = GST_STATE (element);
2397 /* when we were PLAYING, the new state is PAUSED. We will also not
2398 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2399 * when we preroll. */
2400 if (old_state > GST_STATE_PAUSED)
2401 new_state = GST_STATE_PAUSED;
2403 new_state = old_state;
2405 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2406 "lost state of %s to %s", gst_element_state_get_name (old_state),
2407 gst_element_state_get_name (new_state));
2409 GST_STATE (element) = new_state;
2410 GST_STATE_NEXT (element) = new_state;
2411 GST_STATE_PENDING (element) = new_state;
2412 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2414 GST_ELEMENT_START_TIME (element) = 0;
2415 GST_OBJECT_UNLOCK (element);
2417 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2420 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2421 gst_element_post_message (element, message);
2427 GST_OBJECT_UNLOCK (element);
2432 GST_OBJECT_UNLOCK (element);
2434 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2435 gst_element_post_message (element, message);
2441 * gst_element_set_state:
2442 * @element: a #GstElement to change state of.
2443 * @state: the element's new #GstState.
2445 * Sets the state of the element. This function will try to set the
2446 * requested state by going through all the intermediary states and calling
2447 * the class's state change function for each.
2449 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2450 * element will perform the remainder of the state change asynchronously in
2452 * An application can use gst_element_get_state() to wait for the completion
2453 * of the state change or it can wait for a state change message on the bus.
2455 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2456 * #GST_STATE_CHANGE_ASYNC.
2458 * Returns: Result of the state change using #GstStateChangeReturn.
2462 GstStateChangeReturn
2463 gst_element_set_state (GstElement * element, GstState state)
2465 GstElementClass *oclass;
2466 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2468 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2470 oclass = GST_ELEMENT_GET_CLASS (element);
2472 if (oclass->set_state)
2473 result = (oclass->set_state) (element, state);
2479 * default set state function, calculates the next state based
2480 * on current state and calls the change_state function
2482 static GstStateChangeReturn
2483 gst_element_set_state_func (GstElement * element, GstState state)
2485 GstState current, next, old_pending;
2486 GstStateChangeReturn ret;
2487 GstStateChange transition;
2488 GstStateChangeReturn old_ret;
2490 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2492 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2493 gst_element_state_get_name (state));
2495 /* state lock is taken to protect the set_state() and get_state()
2496 * procedures, it does not lock any variables. */
2497 GST_STATE_LOCK (element);
2499 /* now calculate how to get to the new state */
2500 GST_OBJECT_LOCK (element);
2501 old_ret = GST_STATE_RETURN (element);
2502 /* previous state change returned an error, remove all pending
2503 * and next states */
2504 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2505 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2506 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2507 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2510 current = GST_STATE (element);
2511 next = GST_STATE_NEXT (element);
2512 old_pending = GST_STATE_PENDING (element);
2514 /* this is the (new) state we should go to. TARGET is the last state we set on
2516 if (state != GST_STATE_TARGET (element)) {
2517 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2518 "setting target state to %s", gst_element_state_get_name (state));
2519 GST_STATE_TARGET (element) = state;
2520 /* increment state cookie so that we can track each state change. We only do
2521 * this if this is actually a new state change. */
2522 element->state_cookie++;
2524 GST_STATE_PENDING (element) = state;
2526 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2527 "current %s, old_pending %s, next %s, old return %s",
2528 gst_element_state_get_name (current),
2529 gst_element_state_get_name (old_pending),
2530 gst_element_state_get_name (next),
2531 gst_element_state_change_return_get_name (old_ret));
2533 /* if the element was busy doing a state change, we just update the
2534 * target state, it'll get to it async then. */
2535 if (old_pending != GST_STATE_VOID_PENDING) {
2536 /* upwards state change will happen ASYNC */
2537 if (old_pending <= state)
2539 /* element is going to this state already */
2540 else if (next == state)
2542 /* element was performing an ASYNC upward state change and
2543 * we request to go downward again. Start from the next pending
2545 else if (next > state
2546 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2550 next = GST_STATE_GET_NEXT (current, state);
2551 /* now we store the next state */
2552 GST_STATE_NEXT (element) = next;
2553 /* mark busy, we need to check that there is actually a state change
2554 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2555 * the default element change_state function has no way to know what the
2556 * old value was... could consider this a FIXME...*/
2557 if (current != next)
2558 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2560 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2562 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2563 "%s: setting state from %s to %s",
2564 (next != state ? "intermediate" : "final"),
2565 gst_element_state_get_name (current), gst_element_state_get_name (next));
2567 /* now signal any waiters, they will error since the cookie was incremented */
2568 GST_STATE_BROADCAST (element);
2570 GST_OBJECT_UNLOCK (element);
2572 ret = gst_element_change_state (element, transition);
2574 GST_STATE_UNLOCK (element);
2576 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2577 gst_element_state_change_return_get_name (ret));
2583 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2584 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2585 "element was busy with async state change");
2586 GST_OBJECT_UNLOCK (element);
2588 GST_STATE_UNLOCK (element);
2590 return GST_STATE_CHANGE_ASYNC;
2595 * gst_element_change_state:
2596 * @element: a #GstElement
2597 * @transition: the requested transition
2599 * Perform @transition on @element.
2601 * This function must be called with STATE_LOCK held and is mainly used
2604 * Returns: the #GstStateChangeReturn of the state transition.
2606 GstStateChangeReturn
2607 gst_element_change_state (GstElement * element, GstStateChange transition)
2609 GstElementClass *oclass;
2610 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2612 oclass = GST_ELEMENT_GET_CLASS (element);
2614 /* call the state change function so it can set the state */
2615 if (oclass->change_state)
2616 ret = (oclass->change_state) (element, transition);
2618 ret = GST_STATE_CHANGE_FAILURE;
2621 case GST_STATE_CHANGE_FAILURE:
2622 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2623 "have FAILURE change_state return");
2624 /* state change failure */
2625 gst_element_abort_state (element);
2627 case GST_STATE_CHANGE_ASYNC:
2631 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2632 "element will change state ASYNC");
2634 target = GST_STATE_TARGET (element);
2636 if (target > GST_STATE_READY)
2639 /* else we just continue the state change downwards */
2640 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2641 "forcing commit state %s <= %s",
2642 gst_element_state_get_name (target),
2643 gst_element_state_get_name (GST_STATE_READY));
2645 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2648 case GST_STATE_CHANGE_SUCCESS:
2649 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2650 "element changed state SUCCESS");
2651 /* we can commit the state now which will proceeed to
2653 ret = gst_element_continue_state (element, ret);
2655 case GST_STATE_CHANGE_NO_PREROLL:
2656 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2657 "element changed state NO_PREROLL");
2658 /* we can commit the state now which will proceeed to
2660 ret = gst_element_continue_state (element, ret);
2663 goto invalid_return;
2666 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2671 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2679 GST_OBJECT_LOCK (element);
2680 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2681 g_critical ("%s: unknown return value %d from a state change function",
2682 GST_ELEMENT_NAME (element), ret);
2684 /* we are in error now */
2685 ret = GST_STATE_CHANGE_FAILURE;
2686 GST_STATE_RETURN (element) = ret;
2687 GST_OBJECT_UNLOCK (element);
2693 /* gst_iterator_fold functions for pads_activate
2694 * Stop the iterator if activating one pad failed. */
2696 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2698 GstPad *pad = g_value_get_object (vpad);
2699 gboolean cont = TRUE;
2701 if (!(cont = gst_pad_set_active (pad, *active)))
2702 g_value_set_boolean (ret, FALSE);
2707 /* returns false on error or early cutout of the fold, true if all
2708 * pads in @iter were (de)activated successfully. */
2710 iterator_activate_fold_with_resync (GstIterator * iter,
2711 GstIteratorFoldFunction func, gpointer user_data)
2713 GstIteratorResult ires;
2716 /* no need to unset this later, it's just a boolean */
2717 g_value_init (&ret, G_TYPE_BOOLEAN);
2718 g_value_set_boolean (&ret, TRUE);
2721 ires = gst_iterator_fold (iter, func, &ret, user_data);
2723 case GST_ITERATOR_RESYNC:
2724 /* need to reset the result again */
2725 g_value_set_boolean (&ret, TRUE);
2726 gst_iterator_resync (iter);
2728 case GST_ITERATOR_DONE:
2729 /* all pads iterated, return collected value */
2732 /* iterator returned _ERROR or premature end with _OK,
2733 * mark an error and exit */
2734 g_value_set_boolean (&ret, FALSE);
2739 /* return collected value */
2740 return g_value_get_boolean (&ret);
2743 /* is called with STATE_LOCK
2745 * Pads are activated from source pads to sinkpads.
2748 gst_element_pads_activate (GstElement * element, gboolean active)
2753 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2754 "pads_activate with active %d", active);
2756 iter = gst_element_iterate_src_pads (element);
2758 iterator_activate_fold_with_resync (iter,
2759 (GstIteratorFoldFunction) activate_pads, &active);
2760 gst_iterator_free (iter);
2761 if (G_UNLIKELY (!res))
2764 iter = gst_element_iterate_sink_pads (element);
2766 iterator_activate_fold_with_resync (iter,
2767 (GstIteratorFoldFunction) activate_pads, &active);
2768 gst_iterator_free (iter);
2769 if (G_UNLIKELY (!res))
2772 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2773 "pads_activate successful");
2780 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2781 "source pads_activate failed");
2786 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2787 "sink pads_activate failed");
2792 /* is called with STATE_LOCK */
2793 static GstStateChangeReturn
2794 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2796 GstState state, next;
2797 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2799 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2801 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2802 next = GST_STATE_TRANSITION_NEXT (transition);
2804 /* if the element already is in the given state, we just return success */
2805 if (next == GST_STATE_VOID_PENDING || state == next)
2808 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2809 "default handler tries setting state from %s to %s (%04x)",
2810 gst_element_state_get_name (state),
2811 gst_element_state_get_name (next), transition);
2813 switch (transition) {
2814 case GST_STATE_CHANGE_NULL_TO_READY:
2816 case GST_STATE_CHANGE_READY_TO_PAUSED:
2817 if (!gst_element_pads_activate (element, TRUE)) {
2818 result = GST_STATE_CHANGE_FAILURE;
2821 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2823 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2825 case GST_STATE_CHANGE_PAUSED_TO_READY:
2826 case GST_STATE_CHANGE_READY_TO_NULL:
2827 /* deactivate pads in both cases, since they are activated on
2828 ready->paused but the element might not have made it to paused */
2829 if (!gst_element_pads_activate (element, FALSE)) {
2830 result = GST_STATE_CHANGE_FAILURE;
2834 /* this will catch real but unhandled state changes;
2835 * can only be caused by:
2836 * - a new state was added
2837 * - somehow the element was asked to jump across an intermediate state
2839 g_warning ("Unhandled state change from %s to %s",
2840 gst_element_state_get_name (state),
2841 gst_element_state_get_name (next));
2848 GST_OBJECT_LOCK (element);
2849 result = GST_STATE_RETURN (element);
2850 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2851 "element is already in the %s state",
2852 gst_element_state_get_name (state));
2853 GST_OBJECT_UNLOCK (element);
2860 * gst_element_get_factory:
2861 * @element: a #GstElement to request the element factory of.
2863 * Retrieves the factory that was used to create this element.
2865 * Returns: (transfer none): the #GstElementFactory used for creating this
2866 * element. no refcounting is needed.
2869 gst_element_get_factory (GstElement * element)
2871 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2873 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2877 gst_element_dispose (GObject * object)
2879 GstElement *element = GST_ELEMENT_CAST (object);
2883 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2885 if (GST_STATE (element) != GST_STATE_NULL)
2888 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2889 "removing %d pads", g_list_length (element->pads));
2890 /* first we break all our links with the outside */
2891 while (element->pads && element->pads->data) {
2892 /* don't call _remove_pad with NULL */
2893 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2895 if (G_UNLIKELY (element->pads != NULL)) {
2896 g_critical ("could not remove pads from element %s",
2897 GST_STR_NULL (GST_OBJECT_NAME (object)));
2900 GST_OBJECT_LOCK (element);
2901 clock_p = &element->clock;
2902 bus_p = &element->bus;
2903 gst_object_replace ((GstObject **) clock_p, NULL);
2904 gst_object_replace ((GstObject **) bus_p, NULL);
2905 GST_OBJECT_UNLOCK (element);
2907 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2909 G_OBJECT_CLASS (parent_class)->dispose (object);
2918 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2920 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2922 "You need to explicitly set elements to the NULL state before\n"
2923 "dropping the final reference, to allow them to clean up.\n"
2924 "This problem may also be caused by a refcounting bug in the\n"
2925 "application or some element.\n",
2926 GST_OBJECT_NAME (element),
2927 gst_element_state_get_name (GST_STATE (element)),
2928 is_locked ? " (locked)" : "");
2934 gst_element_finalize (GObject * object)
2936 GstElement *element = GST_ELEMENT_CAST (object);
2938 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2940 GST_STATE_LOCK (element);
2941 if (element->state_cond)
2942 g_cond_free (element->state_cond);
2943 element->state_cond = NULL;
2944 GST_STATE_UNLOCK (element);
2945 g_static_rec_mutex_free (element->state_lock);
2946 g_slice_free (GStaticRecMutex, element->state_lock);
2947 element->state_lock = NULL;
2949 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2951 G_OBJECT_CLASS (parent_class)->finalize (object);
2955 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2959 g_return_if_fail (GST_IS_ELEMENT (element));
2961 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2963 GST_OBJECT_LOCK (element);
2964 bus_p = &GST_ELEMENT_BUS (element);
2965 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2966 GST_OBJECT_UNLOCK (element);
2970 * gst_element_set_bus:
2971 * @element: a #GstElement to set the bus of.
2972 * @bus: (transfer none): the #GstBus to set.
2974 * Sets the bus of the element. Increases the refcount on the bus.
2975 * For internal use only, unless you're testing elements.
2980 gst_element_set_bus (GstElement * element, GstBus * bus)
2982 GstElementClass *oclass;
2984 g_return_if_fail (GST_IS_ELEMENT (element));
2986 oclass = GST_ELEMENT_GET_CLASS (element);
2988 if (oclass->set_bus)
2989 oclass->set_bus (element, bus);
2993 * gst_element_get_bus:
2994 * @element: a #GstElement to get the bus of.
2996 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2997 * bus for the application.
2999 * Returns: (transfer full): the element's #GstBus. unref after usage.
3004 gst_element_get_bus (GstElement * element)
3006 GstBus *result = NULL;
3008 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3010 GST_OBJECT_LOCK (element);
3011 if ((result = GST_ELEMENT_BUS (element)))
3012 gst_object_ref (result);
3013 GST_OBJECT_UNLOCK (element);
3015 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,