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;
178 gobject_class = (GObjectClass *) klass;
180 parent_class = g_type_class_peek_parent (klass);
183 * GstElement::pad-added:
184 * @gstelement: the object which received the signal
185 * @new_pad: the pad that has been added
187 * a new #GstPad has been added to the element. Note that this signal will
188 * usually be emitted from the context of the streaming thread. Also keep in
189 * mind that if you add new elements to the pipeline in the signal handler
190 * you will need to set them to the desired target state with
191 * gst_element_set_state() or gst_element_sync_state_with_parent().
193 gst_element_signals[PAD_ADDED] =
194 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
195 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
196 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
198 * GstElement::pad-removed:
199 * @gstelement: the object which received the signal
200 * @old_pad: the pad that has been removed
202 * a #GstPad has been removed from the element
204 gst_element_signals[PAD_REMOVED] =
205 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
206 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
207 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
209 * GstElement::no-more-pads:
210 * @gstelement: the object which received the signal
212 * This signals that the element will not generate more dynamic pads.
213 * Note that this signal will usually be emitted from the context of
214 * the streaming thread.
216 gst_element_signals[NO_MORE_PADS] =
217 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
218 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
219 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
221 gobject_class->dispose = gst_element_dispose;
222 gobject_class->finalize = gst_element_finalize;
224 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
225 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
226 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
227 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
228 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
229 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
230 klass->numpadtemplates = 0;
232 klass->elementfactory = NULL;
236 gst_element_base_class_init (gpointer g_class)
238 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
239 GList *node, *padtemplates;
241 /* Copy the element details here so elements can inherit the
242 * details from their base class and classes only need to set
243 * the details in class_init instead of base_init */
244 element_class->metadata =
245 element_class->metadata ? gst_structure_copy (element_class->metadata) :
246 gst_structure_empty_new ("metadata");
248 /* Copy the pad templates so elements inherit them
249 * from their base class but elements can add pad templates in class_init
250 * instead of base_init.
252 padtemplates = g_list_copy (element_class->padtemplates);
253 for (node = padtemplates; node != NULL; node = node->next) {
254 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
255 gst_object_ref (tmpl);
257 element_class->padtemplates = padtemplates;
259 /* set the factory, see gst_element_register() */
260 element_class->elementfactory =
261 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
262 _gst_elementclass_factory);
263 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
264 element_class->elementfactory);
268 gst_element_base_class_finalize (gpointer g_class)
270 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
272 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
273 g_list_free (klass->padtemplates);
275 gst_structure_free (klass->metadata);
279 gst_element_init (GstElement * element)
281 GST_STATE (element) = GST_STATE_NULL;
282 GST_STATE_TARGET (element) = GST_STATE_NULL;
283 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
284 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
285 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
287 g_static_rec_mutex_init (&element->state_lock);
288 element->state_cond = g_cond_new ();
292 * gst_element_release_request_pad:
293 * @element: a #GstElement to release the request pad of.
294 * @pad: the #GstPad to release.
296 * Makes the element free the previously requested pad as obtained
297 * with gst_element_get_request_pad().
299 * This does not unref the pad. If the pad was created by using
300 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
301 * followed by gst_object_unref() to free the @pad.
306 gst_element_release_request_pad (GstElement * element, GstPad * pad)
308 GstElementClass *oclass;
310 g_return_if_fail (GST_IS_ELEMENT (element));
311 g_return_if_fail (GST_IS_PAD (pad));
313 oclass = GST_ELEMENT_GET_CLASS (element);
315 /* if the element implements a custom release function we call that, else we
316 * simply remove the pad from the element */
317 if (oclass->release_pad)
318 (oclass->release_pad) (element, pad);
320 gst_element_remove_pad (element, pad);
324 * gst_element_requires_clock:
325 * @element: a #GstElement to query
327 * Query if the element requires a clock.
329 * Returns: %TRUE if the element requires a clock
334 gst_element_requires_clock (GstElement * element)
338 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
340 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
346 * gst_element_provides_clock:
347 * @element: a #GstElement to query
349 * Query if the element provides a clock. A #GstClock provided by an
350 * element can be used as the global #GstClock for the pipeline.
351 * An element that can provide a clock is only required to do so in the PAUSED
352 * state, this means when it is fully negotiated and has allocated the resources
353 * to operate the clock.
355 * Returns: %TRUE if the element provides a clock
360 gst_element_provides_clock (GstElement * element)
364 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
366 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
372 * gst_element_provide_clock:
373 * @element: a #GstElement to query
375 * Get the clock provided by the given element.
376 * <note>An element is only required to provide a clock in the PAUSED
377 * state. Some elements can provide a clock in other states.</note>
379 * Returns: (transfer full): the GstClock provided by the element or %NULL
380 * if no clock could be provided. Unref after usage.
385 gst_element_provide_clock (GstElement * element)
387 GstClock *result = NULL;
388 GstElementClass *oclass;
390 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
392 oclass = GST_ELEMENT_GET_CLASS (element);
394 if (oclass->provide_clock)
395 result = oclass->provide_clock (element);
401 * gst_element_set_clock:
402 * @element: a #GstElement to set the clock for.
403 * @clock: the #GstClock to set for the element.
405 * Sets the clock for the element. This function increases the
406 * refcount on the clock. Any previously set clock on the object
409 * Returns: %TRUE if the element accepted the clock. An element can refuse a
410 * clock when it, for example, is not able to slave its internal clock to the
411 * @clock or when it requires a specific clock to operate.
416 gst_element_set_clock (GstElement * element, GstClock * clock)
418 GstElementClass *oclass;
422 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
423 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
425 oclass = GST_ELEMENT_GET_CLASS (element);
427 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
429 if (oclass->set_clock)
430 res = oclass->set_clock (element, clock);
433 /* only update the clock pointer if the element accepted the clock */
434 GST_OBJECT_LOCK (element);
435 clock_p = &element->clock;
436 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
437 GST_OBJECT_UNLOCK (element);
443 * gst_element_get_clock:
444 * @element: a #GstElement to get the clock of.
446 * Gets the currently configured clock of the element. This is the clock as was
447 * last set with gst_element_set_clock().
449 * Returns: (transfer full): the #GstClock of the element. unref after usage.
454 gst_element_get_clock (GstElement * element)
458 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
460 GST_OBJECT_LOCK (element);
461 if ((result = element->clock))
462 gst_object_ref (result);
463 GST_OBJECT_UNLOCK (element);
469 * gst_element_set_base_time:
470 * @element: a #GstElement.
471 * @time: the base time to set.
473 * Set the base time of an element. See gst_element_get_base_time().
478 gst_element_set_base_time (GstElement * element, GstClockTime time)
482 g_return_if_fail (GST_IS_ELEMENT (element));
484 GST_OBJECT_LOCK (element);
485 old = element->base_time;
486 element->base_time = time;
487 GST_OBJECT_UNLOCK (element);
489 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
490 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
491 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
495 * gst_element_get_base_time:
496 * @element: a #GstElement.
498 * Returns the base time of the element. The base time is the
499 * absolute time of the clock when this element was last put to
500 * PLAYING. Subtracting the base time from the clock time gives
501 * the running time of the element.
503 * Returns: the base time of the element.
508 gst_element_get_base_time (GstElement * element)
512 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
514 GST_OBJECT_LOCK (element);
515 result = element->base_time;
516 GST_OBJECT_UNLOCK (element);
522 * gst_element_set_start_time:
523 * @element: a #GstElement.
524 * @time: the base time to set.
526 * Set the start time of an element. The start time of the element is the
527 * running time of the element when it last went to the PAUSED state. In READY
528 * or after a flushing seek, it is set to 0.
530 * Toplevel elements like #GstPipeline will manage the start_time and
531 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
532 * on such a toplevel element will disable the distribution of the base_time to
533 * the children and can be useful if the application manages the base_time
534 * itself, for example if you want to synchronize capture from multiple
535 * pipelines, and you can also ensure that the pipelines have the same clock.
542 gst_element_set_start_time (GstElement * element, GstClockTime time)
546 g_return_if_fail (GST_IS_ELEMENT (element));
548 GST_OBJECT_LOCK (element);
549 old = GST_ELEMENT_START_TIME (element);
550 GST_ELEMENT_START_TIME (element) = time;
551 GST_OBJECT_UNLOCK (element);
553 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
554 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
555 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
559 * gst_element_get_start_time:
560 * @element: a #GstElement.
562 * Returns the start time of the element. The start time is the
563 * running time of the clock when this element was last put to PAUSED.
565 * Usually the start_time is managed by a toplevel element such as
570 * Returns: the start time of the element.
575 gst_element_get_start_time (GstElement * element)
579 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
581 GST_OBJECT_LOCK (element);
582 result = GST_ELEMENT_START_TIME (element);
583 GST_OBJECT_UNLOCK (element);
589 * gst_element_is_indexable:
590 * @element: a #GstElement.
592 * Queries if the element can be indexed.
594 * Returns: TRUE if the element can be indexed.
599 gst_element_is_indexable (GstElement * element)
603 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
605 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
611 * gst_element_set_index:
612 * @element: a #GstElement.
613 * @index: (transfer none): a #GstIndex.
615 * Set @index on the element. The refcount of the index
616 * will be increased, any previously set index is unreffed.
621 gst_element_set_index (GstElement * element, GstIndex * index)
623 GstElementClass *oclass;
625 g_return_if_fail (GST_IS_ELEMENT (element));
626 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
628 oclass = GST_ELEMENT_GET_CLASS (element);
630 if (oclass->set_index)
631 oclass->set_index (element, index);
635 * gst_element_get_index:
636 * @element: a #GstElement.
638 * Gets the index from the element.
640 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
641 * element. unref after usage.
646 gst_element_get_index (GstElement * element)
648 GstElementClass *oclass;
649 GstIndex *result = NULL;
651 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
653 oclass = GST_ELEMENT_GET_CLASS (element);
655 if (oclass->get_index)
656 result = oclass->get_index (element);
662 * gst_element_add_pad:
663 * @element: a #GstElement to add the pad to.
664 * @pad: (transfer full): the #GstPad to add to the element.
666 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
667 * see gst_object_set_parent() for refcounting information.
669 * Pads are not automatically activated so elements should perform the needed
670 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
671 * state. See gst_pad_set_active() for more information about activating pads.
673 * The pad and the element should be unlocked when calling this function.
675 * This function will emit the #GstElement::pad-added signal on the element.
677 * Returns: %TRUE if the pad could be added. This function can fail when
678 * a pad with the same name already existed or the pad already had another
684 gst_element_add_pad (GstElement * element, GstPad * pad)
689 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
690 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
692 /* locking pad to look at the name */
693 GST_OBJECT_LOCK (pad);
694 pad_name = g_strdup (GST_PAD_NAME (pad));
695 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
696 GST_STR_NULL (pad_name));
697 flushing = GST_PAD_IS_FLUSHING (pad);
698 GST_OBJECT_UNLOCK (pad);
700 /* then check to see if there's already a pad by that name here */
701 GST_OBJECT_LOCK (element);
702 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
705 /* try to set the pad's parent */
706 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
707 GST_OBJECT_CAST (element))))
710 /* check for flushing pads */
711 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
712 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
713 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
714 "use gst_pad_set_active(pad,TRUE) before adding it.",
715 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
717 GST_OBJECT_LOCK (pad);
718 GST_PAD_UNSET_FLUSHING (pad);
719 GST_OBJECT_UNLOCK (pad);
724 /* add it to the list */
725 switch (gst_pad_get_direction (pad)) {
727 element->srcpads = g_list_prepend (element->srcpads, pad);
728 element->numsrcpads++;
731 element->sinkpads = g_list_prepend (element->sinkpads, pad);
732 element->numsinkpads++;
737 element->pads = g_list_prepend (element->pads, pad);
739 element->pads_cookie++;
740 GST_OBJECT_UNLOCK (element);
742 /* emit the PAD_ADDED signal */
743 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
750 g_critical ("Padname %s is not unique in element %s, not adding",
751 pad_name, GST_ELEMENT_NAME (element));
752 GST_OBJECT_UNLOCK (element);
759 ("Pad %s already has parent when trying to add to element %s",
760 pad_name, GST_ELEMENT_NAME (element));
761 GST_OBJECT_UNLOCK (element);
767 GST_OBJECT_LOCK (pad);
769 ("Trying to add pad %s to element %s, but it has no direction",
770 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
771 GST_OBJECT_UNLOCK (pad);
772 GST_OBJECT_UNLOCK (element);
778 * gst_element_remove_pad:
779 * @element: a #GstElement to remove pad from.
780 * @pad: (transfer none): the #GstPad to remove from the element.
782 * Removes @pad from @element. @pad will be destroyed if it has not been
783 * referenced elsewhere using gst_object_unparent().
785 * This function is used by plugin developers and should not be used
786 * by applications. Pads that were dynamically requested from elements
787 * with gst_element_get_request_pad() should be released with the
788 * gst_element_release_request_pad() function instead.
790 * Pads are not automatically deactivated so elements should perform the needed
791 * steps to deactivate the pad in case this pad is removed in the PAUSED or
792 * PLAYING state. See gst_pad_set_active() for more information about
795 * The pad and the element should be unlocked when calling this function.
797 * This function will emit the #GstElement::pad-removed signal on the element.
799 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
800 * pad does not belong to the provided element.
805 gst_element_remove_pad (GstElement * element, GstPad * pad)
809 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
810 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
812 /* locking pad to look at the name and parent */
813 GST_OBJECT_LOCK (pad);
814 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
815 GST_STR_NULL (GST_PAD_NAME (pad)));
817 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
819 GST_OBJECT_UNLOCK (pad);
822 if ((peer = gst_pad_get_peer (pad))) {
823 /* window for MT unsafeness, someone else could unlink here
824 * and then we call unlink with wrong pads. The unlink
825 * function would catch this and safely return failed. */
826 if (GST_PAD_IS_SRC (pad))
827 gst_pad_unlink (pad, peer);
829 gst_pad_unlink (peer, pad);
831 gst_object_unref (peer);
834 GST_OBJECT_LOCK (element);
835 /* remove it from the list */
836 switch (gst_pad_get_direction (pad)) {
838 element->srcpads = g_list_remove (element->srcpads, pad);
839 element->numsrcpads--;
842 element->sinkpads = g_list_remove (element->sinkpads, pad);
843 element->numsinkpads--;
846 g_critical ("Removing pad without direction???");
849 element->pads = g_list_remove (element->pads, pad);
851 element->pads_cookie++;
852 GST_OBJECT_UNLOCK (element);
854 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
855 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
857 gst_object_unparent (GST_OBJECT_CAST (pad));
864 /* locking order is element > pad */
865 GST_OBJECT_UNLOCK (pad);
867 GST_OBJECT_LOCK (element);
868 GST_OBJECT_LOCK (pad);
869 g_critical ("Padname %s:%s does not belong to element %s when removing",
870 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
871 GST_OBJECT_UNLOCK (pad);
872 GST_OBJECT_UNLOCK (element);
878 * gst_element_no_more_pads:
879 * @element: a #GstElement
881 * Use this function to signal that the element does not expect any more pads
882 * to show up in the current pipeline. This function should be called whenever
883 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
884 * pad templates use this in combination with autopluggers to figure out that
885 * the element is done initializing its pads.
887 * This function emits the #GstElement::no-more-pads signal.
892 gst_element_no_more_pads (GstElement * element)
894 g_return_if_fail (GST_IS_ELEMENT (element));
896 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
900 pad_compare_name (GstPad * pad1, const gchar * name)
904 GST_OBJECT_LOCK (pad1);
905 result = strcmp (GST_PAD_NAME (pad1), name);
906 GST_OBJECT_UNLOCK (pad1);
912 * gst_element_get_static_pad:
913 * @element: a #GstElement to find a static pad of.
914 * @name: the name of the static #GstPad to retrieve.
916 * Retrieves a pad from @element by name. This version only retrieves
917 * already-existing (i.e. 'static') pads.
919 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
925 gst_element_get_static_pad (GstElement * element, const gchar * name)
928 GstPad *result = NULL;
930 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
931 g_return_val_if_fail (name != NULL, NULL);
933 GST_OBJECT_LOCK (element);
935 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
937 result = GST_PAD_CAST (find->data);
938 gst_object_ref (result);
941 if (result == NULL) {
942 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
943 name, GST_ELEMENT_NAME (element));
945 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
946 GST_ELEMENT_NAME (element), name);
948 GST_OBJECT_UNLOCK (element);
954 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
955 const gchar * name, const GstCaps * caps)
957 GstPad *newpad = NULL;
958 GstElementClass *oclass;
960 oclass = GST_ELEMENT_GET_CLASS (element);
962 #ifndef G_DISABLE_CHECKS
963 /* Some sanity checking here */
967 /* Is this the template name? */
968 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
969 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
971 const gchar *str, *data;
974 /* Otherwise check if it's a valid name for the name template */
975 str = strchr (templ->name_template, '%');
976 g_return_val_if_fail (str != NULL, NULL);
977 g_return_val_if_fail (strncmp (templ->name_template, name,
978 str - templ->name_template) == 0, NULL);
979 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
981 data = name + (str - templ->name_template);
983 /* Can either be %s or %d or %u, do sanity checking for %d */
984 if (*(str + 1) == 'd') {
988 tmp = g_ascii_strtoll (data, &endptr, 10);
989 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
990 && *endptr == '\0', NULL);
991 } else if (*(str + 1) == 'u') {
995 tmp = g_ascii_strtoull (data, &endptr, 10);
996 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
1000 pad = gst_element_get_static_pad (element, name);
1002 gst_object_unref (pad);
1003 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1004 g_critical ("Element %s already has a pad named %s, the behaviour of "
1005 " gst_element_get_request_pad() for existing pads is undefined!",
1006 GST_ELEMENT_NAME (element), name);
1011 if (oclass->request_new_pad)
1012 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1015 gst_object_ref (newpad);
1021 * gst_element_get_request_pad:
1022 * @element: a #GstElement to find a request pad of.
1023 * @name: the name of the request #GstPad to retrieve.
1025 * Retrieves a pad from the element by name. This version only retrieves
1026 * request pads. The pad should be released with
1027 * gst_element_release_request_pad().
1029 * This method is slow and will be deprecated in the future. New code should
1030 * use gst_element_request_pad() with the requested template.
1032 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1033 * Release after usage.
1036 gst_element_get_request_pad (GstElement * element, const gchar * name)
1038 GstPadTemplate *templ = NULL;
1040 const gchar *req_name = NULL;
1041 gboolean templ_found = FALSE;
1044 gchar *str, *endptr = NULL;
1045 GstElementClass *class;
1047 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1048 g_return_val_if_fail (name != NULL, NULL);
1050 class = GST_ELEMENT_GET_CLASS (element);
1052 /* if the name contains a %, we assume it's the complete template name. Get
1053 * the template and try to get a pad */
1054 if (strstr (name, "%")) {
1055 templ = gst_element_class_get_request_pad_template (class, name);
1060 /* there is no % in the name, try to find a matching template */
1061 list = class->padtemplates;
1062 while (!templ_found && list) {
1063 templ = (GstPadTemplate *) list->data;
1064 if (templ->presence == GST_PAD_REQUEST) {
1065 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1066 templ->name_template);
1067 /* see if we find an exact match */
1068 if (strcmp (name, templ->name_template) == 0) {
1073 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1074 and %d and %u, occurring at the end of the name_template, are the only
1076 else if ((str = strchr (templ->name_template, '%'))
1077 && strncmp (templ->name_template, name,
1078 str - templ->name_template) == 0
1079 && strlen (name) > str - templ->name_template) {
1080 data = name + (str - templ->name_template);
1081 if (*(str + 1) == 'd') {
1085 tmp = strtol (data, &endptr, 10);
1086 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1092 } else if (*(str + 1) == 'u') {
1096 tmp = strtoul (data, &endptr, 10);
1097 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1117 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1123 * gst_element_request_pad:
1124 * @element: a #GstElement to find a request pad of.
1125 * @templ: a #GstPadTemplate of which we want a pad of.
1126 * @name: (transfer none) (allow-none): the name of the request #GstPad
1127 * to retrieve. Can be %NULL.
1128 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1129 * request. Can be %NULL.
1131 * Retrieves a request pad from the element according to the provided template.
1133 * If the @caps are specified and the element implements thew new
1134 * request_new_pad_full virtual method, the element will use them to select
1135 * which pad to create.
1137 * The pad should be released with gst_element_release_request_pad().
1139 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1140 * Release after usage.
1145 gst_element_request_pad (GstElement * element,
1146 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1148 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1149 g_return_val_if_fail (templ != NULL, NULL);
1151 return _gst_element_request_pad (element, templ, name, caps);
1154 static GstIterator *
1155 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1157 GstIterator *result;
1159 GST_OBJECT_LOCK (element);
1160 result = gst_iterator_new_list (GST_TYPE_PAD,
1161 GST_OBJECT_GET_LOCK (element),
1162 &element->pads_cookie, padlist, (GObject *) element, NULL);
1163 GST_OBJECT_UNLOCK (element);
1169 * gst_element_iterate_pads:
1170 * @element: a #GstElement to iterate pads of.
1172 * Retrieves an iterattor of @element's pads. The iterator should
1173 * be freed after usage.
1175 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1181 gst_element_iterate_pads (GstElement * element)
1183 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1185 return gst_element_iterate_pad_list (element, &element->pads);
1189 * gst_element_iterate_src_pads:
1190 * @element: a #GstElement.
1192 * Retrieves an iterator of @element's source pads.
1194 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1200 gst_element_iterate_src_pads (GstElement * element)
1202 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1204 return gst_element_iterate_pad_list (element, &element->srcpads);
1208 * gst_element_iterate_sink_pads:
1209 * @element: a #GstElement.
1211 * Retrieves an iterator of @element's sink pads.
1213 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1219 gst_element_iterate_sink_pads (GstElement * element)
1221 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1223 return gst_element_iterate_pad_list (element, &element->sinkpads);
1227 * gst_element_class_add_pad_template:
1228 * @klass: the #GstElementClass to add the pad template to.
1229 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1231 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1232 * functions of classes. If a pad template with the same name as an already
1233 * existing one is added the old one is replaced by the new one.
1237 gst_element_class_add_pad_template (GstElementClass * klass,
1238 GstPadTemplate * templ)
1240 GList *template_list = klass->padtemplates;
1242 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1243 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1245 /* If we already have a pad template with the same name replace the
1247 while (template_list) {
1248 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1250 /* Found pad with the same name, replace and return */
1251 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1252 gst_object_unref (padtempl);
1253 template_list->data = templ;
1256 template_list = g_list_next (template_list);
1259 /* Take ownership of the floating ref */
1260 g_object_ref_sink (templ);
1262 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1263 klass->numpadtemplates++;
1267 * gst_element_class_add_metadata:
1268 * @klass: class to set metadata for
1269 * @key: the key to set
1270 * @value: the value to set
1272 * Set @key with @value as metadata in @klass.
1275 gst_element_class_add_metadata (GstElementClass * klass,
1276 const gchar * key, const gchar * value)
1278 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1279 g_return_if_fail (key != NULL);
1280 g_return_if_fail (value != NULL);
1282 gst_structure_set ((GstStructure *) klass->metadata,
1283 key, G_TYPE_STRING, value, NULL);
1287 * gst_element_class_set_metadata:
1288 * @klass: class to set metadata for
1289 * @longname: The long English name of the element. E.g. "File Sink"
1290 * @classification: String describing the type of element, as an unordered list
1291 * separated with slashes ('/'). See draft-klass.txt of the design docs
1292 * for more details and common types. E.g: "Sink/File"
1293 * @description: Sentence describing the purpose of the element.
1294 * E.g: "Write stream to a file"
1295 * @author: Name and contact details of the author(s). Use \n to separate
1296 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1298 * Sets the detailed information for a #GstElementClass.
1299 * <note>This function is for use in _class_init functions only.</note>
1302 gst_element_class_set_metadata (GstElementClass * klass,
1303 const gchar * longname, const gchar * classification,
1304 const gchar * description, const gchar * author)
1306 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1308 gst_structure_set ((GstStructure *) klass->metadata,
1309 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1310 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1311 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1312 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1316 * gst_element_class_get_metadata:
1317 * @klass: class to get metadata for
1318 * @key: the key to get
1320 * Get metadata with @key in @klass.
1322 * Returns: the metadata for @key.
1325 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1327 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1328 g_return_val_if_fail (key != NULL, NULL);
1330 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1334 * gst_element_class_get_pad_template_list:
1335 * @element_class: a #GstElementClass to get pad templates of.
1337 * Retrieves a list of the pad templates associated with @element_class. The
1338 * list must not be modified by the calling code.
1339 * <note>If you use this function in the #GInstanceInitFunc of an object class
1340 * that has subclasses, make sure to pass the g_class parameter of the
1341 * #GInstanceInitFunc here.</note>
1343 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1347 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1349 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1351 return element_class->padtemplates;
1355 * gst_element_class_get_pad_template:
1356 * @element_class: a #GstElementClass to get the pad template of.
1357 * @name: the name of the #GstPadTemplate to get.
1359 * Retrieves a padtemplate from @element_class with the given name.
1360 * <note>If you use this function in the #GInstanceInitFunc of an object class
1361 * that has subclasses, make sure to pass the g_class parameter of the
1362 * #GInstanceInitFunc here.</note>
1364 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1365 * if none was found. No unreferencing is necessary.
1368 gst_element_class_get_pad_template (GstElementClass *
1369 element_class, const gchar * name)
1373 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1374 g_return_val_if_fail (name != NULL, NULL);
1376 padlist = element_class->padtemplates;
1379 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1381 if (strcmp (padtempl->name_template, name) == 0)
1384 padlist = g_list_next (padlist);
1390 static GstPadTemplate *
1391 gst_element_class_get_request_pad_template (GstElementClass *
1392 element_class, const gchar * name)
1394 GstPadTemplate *tmpl;
1396 tmpl = gst_element_class_get_pad_template (element_class, name);
1397 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1403 /* get a random pad on element of the given direction.
1404 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1407 gst_element_get_random_pad (GstElement * element,
1408 gboolean need_linked, GstPadDirection dir)
1410 GstPad *result = NULL;
1413 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1417 GST_OBJECT_LOCK (element);
1418 pads = element->srcpads;
1421 GST_OBJECT_LOCK (element);
1422 pads = element->sinkpads;
1425 goto wrong_direction;
1427 for (; pads; pads = g_list_next (pads)) {
1428 GstPad *pad = GST_PAD_CAST (pads->data);
1430 GST_OBJECT_LOCK (pad);
1431 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1432 GST_DEBUG_PAD_NAME (pad));
1434 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1435 /* if we require a linked pad, and it is not linked, continue the
1437 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1438 GST_DEBUG_PAD_NAME (pad));
1439 GST_OBJECT_UNLOCK (pad);
1442 /* found a pad, stop search */
1443 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1444 GST_DEBUG_PAD_NAME (pad));
1445 GST_OBJECT_UNLOCK (pad);
1451 gst_object_ref (result);
1453 GST_OBJECT_UNLOCK (element);
1457 /* ERROR handling */
1460 g_warning ("unknown pad direction %d", dir);
1466 gst_element_default_send_event (GstElement * element, GstEvent * event)
1468 gboolean result = FALSE;
1471 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1472 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1473 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1476 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1477 "pushing %s event to random %s pad %s:%s",
1478 GST_EVENT_TYPE_NAME (event),
1479 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1480 GST_DEBUG_PAD_NAME (pad));
1482 result = gst_pad_push_event (pad, event);
1483 gst_object_unref (pad);
1485 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1486 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1487 gst_event_unref (event);
1493 * gst_element_send_event:
1494 * @element: a #GstElement to send the event to.
1495 * @event: (transfer full): the #GstEvent to send to the element.
1497 * Sends an event to an element. If the element doesn't implement an
1498 * event handler, the event will be pushed on a random linked sink pad for
1499 * upstream events or a random linked source pad for downstream events.
1501 * This function takes owership of the provided event so you should
1502 * gst_event_ref() it if you want to reuse the event after this call.
1504 * Returns: %TRUE if the event was handled.
1509 gst_element_send_event (GstElement * element, GstEvent * event)
1511 GstElementClass *oclass;
1512 gboolean result = FALSE;
1514 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1515 g_return_val_if_fail (event != NULL, FALSE);
1517 oclass = GST_ELEMENT_GET_CLASS (element);
1519 GST_STATE_LOCK (element);
1520 if (oclass->send_event) {
1521 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1522 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1523 result = oclass->send_event (element, event);
1525 result = gst_element_default_send_event (element, event);
1527 GST_STATE_UNLOCK (element);
1534 * @element: a #GstElement to send the event to.
1535 * @rate: The new playback rate
1536 * @format: The format of the seek values
1537 * @flags: The optional seek flags.
1538 * @cur_type: The type and flags for the new current position
1539 * @cur: The value of the new current position
1540 * @stop_type: The type and flags for the new stop position
1541 * @stop: The value of the new stop position
1543 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1544 * the parameters. The seek event is sent to the element using
1545 * gst_element_send_event().
1547 * Returns: %TRUE if the event was handled.
1552 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1553 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1554 GstSeekType stop_type, gint64 stop)
1559 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1562 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1563 result = gst_element_send_event (element, event);
1569 * gst_element_get_query_types:
1570 * @element: a #GstElement to query
1572 * Get an array of query types from the element.
1573 * If the element doesn't implement a query types function,
1574 * the query will be forwarded to the peer of a random linked sink pad.
1576 * Returns: An array of #GstQueryType elements that should not
1577 * be freed or modified.
1581 const GstQueryType *
1582 gst_element_get_query_types (GstElement * element)
1584 GstElementClass *oclass;
1585 const GstQueryType *result = NULL;
1587 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1589 oclass = GST_ELEMENT_GET_CLASS (element);
1591 if (oclass->get_query_types) {
1592 result = oclass->get_query_types (element);
1594 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1597 GstPad *peer = gst_pad_get_peer (pad);
1600 result = gst_pad_get_query_types (peer);
1602 gst_object_unref (peer);
1604 gst_object_unref (pad);
1611 gst_element_default_query (GstElement * element, GstQuery * query)
1613 gboolean result = FALSE;
1616 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1618 result = gst_pad_query (pad, query);
1620 gst_object_unref (pad);
1622 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1624 GstPad *peer = gst_pad_get_peer (pad);
1627 result = gst_pad_query (peer, query);
1629 gst_object_unref (peer);
1631 gst_object_unref (pad);
1638 * gst_element_query:
1639 * @element: a #GstElement to perform the query on.
1640 * @query: (transfer none): the #GstQuery.
1642 * Performs a query on the given element.
1644 * For elements that don't implement a query handler, this function
1645 * forwards the query to a random srcpad or to the peer of a
1646 * random linked sinkpad of this element.
1648 * Please note that some queries might need a running pipeline to work.
1650 * Returns: TRUE if the query could be performed.
1655 gst_element_query (GstElement * element, GstQuery * query)
1657 GstElementClass *oclass;
1658 gboolean result = FALSE;
1660 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1661 g_return_val_if_fail (query != NULL, FALSE);
1663 oclass = GST_ELEMENT_GET_CLASS (element);
1665 if (oclass->query) {
1666 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1667 GST_ELEMENT_NAME (element));
1668 result = oclass->query (element, query);
1670 result = gst_element_default_query (element, query);
1676 * gst_element_post_message:
1677 * @element: a #GstElement posting the message
1678 * @message: (transfer full): a #GstMessage to post
1680 * Post a message on the element's #GstBus. This function takes ownership of the
1681 * message; if you want to access the message after this call, you should add an
1682 * additional reference before calling.
1684 * Returns: %TRUE if the message was successfully posted. The function returns
1685 * %FALSE if the element did not have a bus.
1690 gst_element_post_message (GstElement * element, GstMessage * message)
1693 gboolean result = FALSE;
1695 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1696 g_return_val_if_fail (message != NULL, FALSE);
1698 GST_OBJECT_LOCK (element);
1701 if (G_UNLIKELY (bus == NULL))
1704 gst_object_ref (bus);
1705 GST_OBJECT_UNLOCK (element);
1707 /* we release the element lock when posting the message so that any
1708 * (synchronous) message handlers can operate on the element */
1709 result = gst_bus_post (bus, message);
1710 gst_object_unref (bus);
1717 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1718 "not posting message %p: no bus", message);
1719 GST_OBJECT_UNLOCK (element);
1720 gst_message_unref (message);
1726 * _gst_element_error_printf:
1727 * @format: the printf-like format to use, or %NULL
1729 * This function is only used internally by the gst_element_error() macro.
1731 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1737 _gst_element_error_printf (const gchar * format, ...)
1747 va_start (args, format);
1748 buffer = g_strdup_vprintf (format, args);
1754 * gst_element_message_full:
1755 * @element: a #GstElement to send message from
1756 * @type: the #GstMessageType
1757 * @domain: the GStreamer GError domain this message belongs to
1758 * @code: the GError code belonging to the domain
1759 * @text: (allow-none) (transfer full): an allocated text string to be used
1760 * as a replacement for the default message connected to code,
1762 * @debug: (allow-none) (transfer full): an allocated debug message to be
1763 * used as a replacement for the default debugging information,
1765 * @file: the source code file where the error was generated
1766 * @function: the source code function where the error was generated
1767 * @line: the source code line where the error was generated
1769 * Post an error, warning or info message on the bus from inside an element.
1771 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1772 * #GST_MESSAGE_INFO.
1776 void gst_element_message_full
1777 (GstElement * element, GstMessageType type,
1778 GQuark domain, gint code, gchar * text,
1779 gchar * debug, const gchar * file, const gchar * function, gint line)
1781 GError *gerror = NULL;
1785 gboolean has_debug = TRUE;
1786 GstMessage *message = NULL;
1789 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1790 g_return_if_fail (GST_IS_ELEMENT (element));
1791 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1792 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1794 /* check if we send the given text or the default error text */
1795 if ((text == NULL) || (text[0] == 0)) {
1796 /* text could have come from g_strdup_printf (""); */
1798 sent_text = gst_error_get_message (domain, code);
1802 /* construct a sent_debug with extra information from source */
1803 if ((debug == NULL) || (debug[0] == 0)) {
1804 /* debug could have come from g_strdup_printf (""); */
1808 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1810 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1811 file, line, function, name, debug);
1813 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1814 file, line, function, name);
1818 /* create gerror and post message */
1819 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1821 gerror = g_error_new_literal (domain, code, sent_text);
1824 case GST_MESSAGE_ERROR:
1826 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1828 case GST_MESSAGE_WARNING:
1829 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1832 case GST_MESSAGE_INFO:
1833 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1837 g_assert_not_reached ();
1840 gst_element_post_message (element, message);
1842 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1843 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1846 g_error_free (gerror);
1847 g_free (sent_debug);
1852 * gst_element_is_locked_state:
1853 * @element: a #GstElement.
1855 * Checks if the state of an element is locked.
1856 * If the state of an element is locked, state changes of the parent don't
1857 * affect the element.
1858 * This way you can leave currently unused elements inside bins. Just lock their
1859 * state before changing the state from #GST_STATE_NULL.
1863 * Returns: TRUE, if the element's state is locked.
1866 gst_element_is_locked_state (GstElement * element)
1870 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1872 GST_OBJECT_LOCK (element);
1873 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1874 GST_OBJECT_UNLOCK (element);
1880 * gst_element_set_locked_state:
1881 * @element: a #GstElement
1882 * @locked_state: TRUE to lock the element's state
1884 * Locks the state of an element, so state changes of the parent don't affect
1885 * this element anymore.
1889 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1890 * or the elements state-locking needed no change.
1893 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1897 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1899 GST_OBJECT_LOCK (element);
1900 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1902 if (G_UNLIKELY (old == locked_state))
1906 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1907 GST_ELEMENT_NAME (element));
1908 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1910 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1911 GST_ELEMENT_NAME (element));
1912 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1914 GST_OBJECT_UNLOCK (element);
1920 GST_CAT_DEBUG (GST_CAT_STATES,
1921 "elements %s was already in locked state %d",
1922 GST_ELEMENT_NAME (element), old);
1923 GST_OBJECT_UNLOCK (element);
1930 * gst_element_sync_state_with_parent:
1931 * @element: a #GstElement.
1933 * Tries to change the state of the element to the same as its parent.
1934 * If this function returns FALSE, the state of element is undefined.
1936 * Returns: TRUE, if the element's state could be synced to the parent's state.
1941 gst_element_sync_state_with_parent (GstElement * element)
1945 GstStateChangeReturn ret;
1947 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1949 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1950 GstState parent_current, parent_pending;
1952 GST_OBJECT_LOCK (parent);
1953 parent_current = GST_STATE (parent);
1954 parent_pending = GST_STATE_PENDING (parent);
1955 GST_OBJECT_UNLOCK (parent);
1957 /* set to pending if there is one, else we set it to the current state of
1959 if (parent_pending != GST_STATE_VOID_PENDING)
1960 target = parent_pending;
1962 target = parent_current;
1964 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1965 "syncing state (%s) to parent %s %s (%s, %s)",
1966 gst_element_state_get_name (GST_STATE (element)),
1967 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1968 gst_element_state_get_name (parent_current),
1969 gst_element_state_get_name (parent_pending));
1971 ret = gst_element_set_state (element, target);
1972 if (ret == GST_STATE_CHANGE_FAILURE)
1975 gst_object_unref (parent);
1979 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1986 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1987 "syncing state failed (%s)",
1988 gst_element_state_change_return_get_name (ret));
1989 gst_object_unref (parent);
1995 static GstStateChangeReturn
1996 gst_element_get_state_func (GstElement * element,
1997 GstState * state, GstState * pending, GstClockTime timeout)
1999 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2000 GstState old_pending;
2002 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2003 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2005 GST_OBJECT_LOCK (element);
2006 ret = GST_STATE_RETURN (element);
2007 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2008 gst_element_state_change_return_get_name (ret));
2010 /* we got an error, report immediately */
2011 if (ret == GST_STATE_CHANGE_FAILURE)
2014 /* we got no_preroll, report immediatly */
2015 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2018 /* no need to wait async if we are not async */
2019 if (ret != GST_STATE_CHANGE_ASYNC)
2022 old_pending = GST_STATE_PENDING (element);
2023 if (old_pending != GST_STATE_VOID_PENDING) {
2024 GTimeVal *timeval, abstimeout;
2027 if (timeout != GST_CLOCK_TIME_NONE) {
2028 glong add = timeout / 1000;
2033 /* make timeout absolute */
2034 g_get_current_time (&abstimeout);
2035 g_time_val_add (&abstimeout, add);
2036 timeval = &abstimeout;
2040 /* get cookie to detect state changes during waiting */
2041 cookie = element->state_cookie;
2043 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2044 "waiting for element to commit state");
2046 /* we have a pending state change, wait for it to complete */
2047 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2048 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2049 /* timeout triggered */
2050 ret = GST_STATE_CHANGE_ASYNC;
2052 if (cookie != element->state_cookie)
2055 /* could be success or failure */
2056 if (old_pending == GST_STATE (element)) {
2057 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2058 ret = GST_STATE_CHANGE_SUCCESS;
2060 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2061 ret = GST_STATE_CHANGE_FAILURE;
2064 /* if nothing is pending anymore we can return SUCCESS */
2065 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2066 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2067 ret = GST_STATE_CHANGE_SUCCESS;
2073 *state = GST_STATE (element);
2075 *pending = GST_STATE_PENDING (element);
2077 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2078 "state current: %s, pending: %s, result: %s",
2079 gst_element_state_get_name (GST_STATE (element)),
2080 gst_element_state_get_name (GST_STATE_PENDING (element)),
2081 gst_element_state_change_return_get_name (ret));
2082 GST_OBJECT_UNLOCK (element);
2089 *state = GST_STATE_VOID_PENDING;
2091 *pending = GST_STATE_VOID_PENDING;
2093 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2095 GST_OBJECT_UNLOCK (element);
2097 return GST_STATE_CHANGE_FAILURE;
2102 * gst_element_get_state:
2103 * @element: a #GstElement to get the state of.
2104 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2106 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2107 * state. Can be %NULL.
2108 * @timeout: a #GstClockTime to specify the timeout for an async
2109 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2111 * Gets the state of the element.
2113 * For elements that performed an ASYNC state change, as reported by
2114 * gst_element_set_state(), this function will block up to the
2115 * specified timeout value for the state change to complete.
2116 * If the element completes the state change or goes into
2117 * an error, this function returns immediately with a return value of
2118 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2120 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2121 * returns the current and pending state immediately.
2123 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2124 * successfully changed its state but is not able to provide data yet.
2125 * This mostly happens for live sources that only produce data in
2126 * %GST_STATE_PLAYING. While the state change return is equivalent to
2127 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2128 * some sink elements might not be able to complete their state change because
2129 * an element is not producing data to complete the preroll. When setting the
2130 * element to playing, the preroll will complete and playback will start.
2132 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2133 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2134 * element is still performing a state change or
2135 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2139 GstStateChangeReturn
2140 gst_element_get_state (GstElement * element,
2141 GstState * state, GstState * pending, GstClockTime timeout)
2143 GstElementClass *oclass;
2144 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2146 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2148 oclass = GST_ELEMENT_GET_CLASS (element);
2150 if (oclass->get_state)
2151 result = (oclass->get_state) (element, state, pending, timeout);
2157 * gst_element_abort_state:
2158 * @element: a #GstElement to abort the state of.
2160 * Abort the state change of the element. This function is used
2161 * by elements that do asynchronous state changes and find out
2162 * something is wrong.
2164 * This function should be called with the STATE_LOCK held.
2169 gst_element_abort_state (GstElement * element)
2173 #ifndef GST_DISABLE_GST_DEBUG
2177 g_return_if_fail (GST_IS_ELEMENT (element));
2179 GST_OBJECT_LOCK (element);
2180 pending = GST_STATE_PENDING (element);
2182 if (pending == GST_STATE_VOID_PENDING ||
2183 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2184 goto nothing_aborted;
2186 #ifndef GST_DISABLE_GST_DEBUG
2187 old_state = GST_STATE (element);
2189 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2190 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2191 gst_element_state_get_name (pending));
2195 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2197 GST_STATE_BROADCAST (element);
2198 GST_OBJECT_UNLOCK (element);
2204 GST_OBJECT_UNLOCK (element);
2209 /* Not static because GstBin has manual state handling too */
2211 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2212 GstState newstate, GstState pending)
2214 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2215 GstMessage *message;
2217 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2218 "notifying about state-changed %s to %s (%s pending)",
2219 gst_element_state_get_name (oldstate),
2220 gst_element_state_get_name (newstate),
2221 gst_element_state_get_name (pending));
2223 if (klass->state_changed)
2224 klass->state_changed (element, oldstate, newstate, pending);
2226 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2227 oldstate, newstate, pending);
2228 gst_element_post_message (element, message);
2232 * gst_element_continue_state:
2233 * @element: a #GstElement to continue the state change of.
2234 * @ret: The previous state return value
2236 * Commit the state change of the element and proceed to the next
2237 * pending state if any. This function is used
2238 * by elements that do asynchronous state changes.
2239 * The core will normally call this method automatically when an
2240 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2242 * If after calling this method the element still has not reached
2243 * the pending state, the next state change is performed.
2245 * This method is used internally and should normally not be called by plugins
2248 * Returns: The result of the commit state change.
2252 GstStateChangeReturn
2253 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2255 GstStateChangeReturn old_ret;
2256 GstState old_state, old_next;
2257 GstState current, next, pending;
2258 GstStateChange transition;
2260 GST_OBJECT_LOCK (element);
2261 old_ret = GST_STATE_RETURN (element);
2262 GST_STATE_RETURN (element) = ret;
2263 pending = GST_STATE_PENDING (element);
2265 /* check if there is something to commit */
2266 if (pending == GST_STATE_VOID_PENDING)
2267 goto nothing_pending;
2269 old_state = GST_STATE (element);
2270 /* this is the state we should go to next */
2271 old_next = GST_STATE_NEXT (element);
2272 /* update current state */
2273 current = GST_STATE (element) = old_next;
2275 /* see if we reached the final state */
2276 if (pending == current)
2279 next = GST_STATE_GET_NEXT (current, pending);
2280 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2282 GST_STATE_NEXT (element) = next;
2284 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2285 GST_OBJECT_UNLOCK (element);
2287 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2288 "committing state from %s to %s, pending %s, next %s",
2289 gst_element_state_get_name (old_state),
2290 gst_element_state_get_name (old_next),
2291 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2293 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2295 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2296 "continue state change %s to %s, final %s",
2297 gst_element_state_get_name (current),
2298 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2300 ret = gst_element_change_state (element, transition);
2306 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2307 GST_OBJECT_UNLOCK (element);
2312 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2313 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2315 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2316 "completed state change to %s", gst_element_state_get_name (pending));
2317 GST_OBJECT_UNLOCK (element);
2319 /* don't post silly messages with the same state. This can happen
2320 * when an element state is changed to what it already was. For bins
2321 * this can be the result of a lost state, which we check with the
2322 * previous return value.
2323 * We do signal the cond though as a _get_state() might be blocking
2325 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2326 _priv_gst_element_state_changed (element, old_state, old_next,
2327 GST_STATE_VOID_PENDING);
2329 GST_STATE_BROADCAST (element);
2336 * gst_element_lost_state:
2337 * @element: a #GstElement the state is lost of
2339 * Brings the element to the lost state. The current state of the
2340 * element is copied to the pending state so that any call to
2341 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2343 * An ASYNC_START message is posted. If the element was PLAYING, it will
2344 * go to PAUSED. The element will be restored to its PLAYING state by
2345 * the parent pipeline when it prerolls again.
2347 * This is mostly used for elements that lost their preroll buffer
2348 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2349 * they will go to their pending state again when a new preroll buffer is
2350 * queued. This function can only be called when the element is currently
2351 * not in error or an async state change.
2353 * This function is used internally and should normally not be called from
2354 * plugins or applications.
2357 gst_element_lost_state (GstElement * element)
2359 GstState old_state, new_state;
2360 GstMessage *message;
2362 g_return_if_fail (GST_IS_ELEMENT (element));
2364 GST_OBJECT_LOCK (element);
2365 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2368 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2369 goto only_async_start;
2371 old_state = GST_STATE (element);
2373 /* when we were PLAYING, the new state is PAUSED. We will also not
2374 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2375 * when we preroll. */
2376 if (old_state > GST_STATE_PAUSED)
2377 new_state = GST_STATE_PAUSED;
2379 new_state = old_state;
2381 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2382 "lost state of %s to %s", gst_element_state_get_name (old_state),
2383 gst_element_state_get_name (new_state));
2385 GST_STATE (element) = new_state;
2386 GST_STATE_NEXT (element) = new_state;
2387 GST_STATE_PENDING (element) = new_state;
2388 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2389 GST_OBJECT_UNLOCK (element);
2391 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2393 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2394 gst_element_post_message (element, message);
2400 GST_OBJECT_UNLOCK (element);
2405 GST_OBJECT_UNLOCK (element);
2407 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2408 gst_element_post_message (element, message);
2414 * gst_element_set_state:
2415 * @element: a #GstElement to change state of.
2416 * @state: the element's new #GstState.
2418 * Sets the state of the element. This function will try to set the
2419 * requested state by going through all the intermediary states and calling
2420 * the class's state change function for each.
2422 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2423 * element will perform the remainder of the state change asynchronously in
2425 * An application can use gst_element_get_state() to wait for the completion
2426 * of the state change or it can wait for a state change message on the bus.
2428 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2429 * #GST_STATE_CHANGE_ASYNC.
2431 * Returns: Result of the state change using #GstStateChangeReturn.
2435 GstStateChangeReturn
2436 gst_element_set_state (GstElement * element, GstState state)
2438 GstElementClass *oclass;
2439 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2441 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2443 oclass = GST_ELEMENT_GET_CLASS (element);
2445 if (oclass->set_state)
2446 result = (oclass->set_state) (element, state);
2452 * default set state function, calculates the next state based
2453 * on current state and calls the change_state function
2455 static GstStateChangeReturn
2456 gst_element_set_state_func (GstElement * element, GstState state)
2458 GstState current, next, old_pending;
2459 GstStateChangeReturn ret;
2460 GstStateChange transition;
2461 GstStateChangeReturn old_ret;
2463 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2465 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2466 gst_element_state_get_name (state));
2468 /* state lock is taken to protect the set_state() and get_state()
2469 * procedures, it does not lock any variables. */
2470 GST_STATE_LOCK (element);
2472 /* now calculate how to get to the new state */
2473 GST_OBJECT_LOCK (element);
2474 old_ret = GST_STATE_RETURN (element);
2475 /* previous state change returned an error, remove all pending
2476 * and next states */
2477 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2478 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2479 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2480 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2483 current = GST_STATE (element);
2484 next = GST_STATE_NEXT (element);
2485 old_pending = GST_STATE_PENDING (element);
2487 /* this is the (new) state we should go to. TARGET is the last state we set on
2489 if (state != GST_STATE_TARGET (element)) {
2490 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2491 "setting target state to %s", gst_element_state_get_name (state));
2492 GST_STATE_TARGET (element) = state;
2493 /* increment state cookie so that we can track each state change. We only do
2494 * this if this is actually a new state change. */
2495 element->state_cookie++;
2497 GST_STATE_PENDING (element) = state;
2499 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2500 "current %s, old_pending %s, next %s, old return %s",
2501 gst_element_state_get_name (current),
2502 gst_element_state_get_name (old_pending),
2503 gst_element_state_get_name (next),
2504 gst_element_state_change_return_get_name (old_ret));
2506 /* if the element was busy doing a state change, we just update the
2507 * target state, it'll get to it async then. */
2508 if (old_pending != GST_STATE_VOID_PENDING) {
2509 /* upwards state change will happen ASYNC */
2510 if (old_pending <= state)
2512 /* element is going to this state already */
2513 else if (next == state)
2515 /* element was performing an ASYNC upward state change and
2516 * we request to go downward again. Start from the next pending
2518 else if (next > state
2519 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2523 next = GST_STATE_GET_NEXT (current, state);
2524 /* now we store the next state */
2525 GST_STATE_NEXT (element) = next;
2526 /* mark busy, we need to check that there is actually a state change
2527 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2528 * the default element change_state function has no way to know what the
2529 * old value was... could consider this a FIXME...*/
2530 if (current != next)
2531 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2533 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2535 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2536 "%s: setting state from %s to %s",
2537 (next != state ? "intermediate" : "final"),
2538 gst_element_state_get_name (current), gst_element_state_get_name (next));
2540 /* now signal any waiters, they will error since the cookie was incremented */
2541 GST_STATE_BROADCAST (element);
2543 GST_OBJECT_UNLOCK (element);
2545 ret = gst_element_change_state (element, transition);
2547 GST_STATE_UNLOCK (element);
2549 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2550 gst_element_state_change_return_get_name (ret));
2556 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2557 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2558 "element was busy with async state change");
2559 GST_OBJECT_UNLOCK (element);
2561 GST_STATE_UNLOCK (element);
2563 return GST_STATE_CHANGE_ASYNC;
2568 * gst_element_change_state:
2569 * @element: a #GstElement
2570 * @transition: the requested transition
2572 * Perform @transition on @element.
2574 * This function must be called with STATE_LOCK held and is mainly used
2577 * Returns: the #GstStateChangeReturn of the state transition.
2579 GstStateChangeReturn
2580 gst_element_change_state (GstElement * element, GstStateChange transition)
2582 GstElementClass *oclass;
2583 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2585 oclass = GST_ELEMENT_GET_CLASS (element);
2587 /* call the state change function so it can set the state */
2588 if (oclass->change_state)
2589 ret = (oclass->change_state) (element, transition);
2591 ret = GST_STATE_CHANGE_FAILURE;
2594 case GST_STATE_CHANGE_FAILURE:
2595 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2596 "have FAILURE change_state return");
2597 /* state change failure */
2598 gst_element_abort_state (element);
2600 case GST_STATE_CHANGE_ASYNC:
2604 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2605 "element will change state ASYNC");
2607 target = GST_STATE_TARGET (element);
2609 if (target > GST_STATE_READY)
2612 /* else we just continue the state change downwards */
2613 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2614 "forcing commit state %s <= %s",
2615 gst_element_state_get_name (target),
2616 gst_element_state_get_name (GST_STATE_READY));
2618 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2621 case GST_STATE_CHANGE_SUCCESS:
2622 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2623 "element changed state SUCCESS");
2624 /* we can commit the state now which will proceeed to
2626 ret = gst_element_continue_state (element, ret);
2628 case GST_STATE_CHANGE_NO_PREROLL:
2629 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2630 "element changed state NO_PREROLL");
2631 /* we can commit the state now which will proceeed to
2633 ret = gst_element_continue_state (element, ret);
2636 goto invalid_return;
2639 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2644 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2652 GST_OBJECT_LOCK (element);
2653 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2654 g_critical ("%s: unknown return value %d from a state change function",
2655 GST_ELEMENT_NAME (element), ret);
2657 /* we are in error now */
2658 ret = GST_STATE_CHANGE_FAILURE;
2659 GST_STATE_RETURN (element) = ret;
2660 GST_OBJECT_UNLOCK (element);
2666 /* gst_iterator_fold functions for pads_activate
2667 * Stop the iterator if activating one pad failed. */
2669 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2671 GstPad *pad = g_value_get_object (vpad);
2672 gboolean cont = TRUE;
2674 if (!(cont = gst_pad_set_active (pad, *active)))
2675 g_value_set_boolean (ret, FALSE);
2680 /* returns false on error or early cutout of the fold, true if all
2681 * pads in @iter were (de)activated successfully. */
2683 iterator_activate_fold_with_resync (GstIterator * iter,
2684 GstIteratorFoldFunction func, gpointer user_data)
2686 GstIteratorResult ires;
2689 /* no need to unset this later, it's just a boolean */
2690 g_value_init (&ret, G_TYPE_BOOLEAN);
2691 g_value_set_boolean (&ret, TRUE);
2694 ires = gst_iterator_fold (iter, func, &ret, user_data);
2696 case GST_ITERATOR_RESYNC:
2697 /* need to reset the result again */
2698 g_value_set_boolean (&ret, TRUE);
2699 gst_iterator_resync (iter);
2701 case GST_ITERATOR_DONE:
2702 /* all pads iterated, return collected value */
2705 /* iterator returned _ERROR or premature end with _OK,
2706 * mark an error and exit */
2707 g_value_set_boolean (&ret, FALSE);
2712 /* return collected value */
2713 return g_value_get_boolean (&ret);
2716 /* is called with STATE_LOCK
2718 * Pads are activated from source pads to sinkpads.
2721 gst_element_pads_activate (GstElement * element, gboolean active)
2726 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2727 "pads_activate with active %d", active);
2729 iter = gst_element_iterate_src_pads (element);
2731 iterator_activate_fold_with_resync (iter,
2732 (GstIteratorFoldFunction) activate_pads, &active);
2733 gst_iterator_free (iter);
2734 if (G_UNLIKELY (!res))
2737 iter = gst_element_iterate_sink_pads (element);
2739 iterator_activate_fold_with_resync (iter,
2740 (GstIteratorFoldFunction) activate_pads, &active);
2741 gst_iterator_free (iter);
2742 if (G_UNLIKELY (!res))
2745 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2746 "pads_activate successful");
2753 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2754 "source pads_activate failed");
2759 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2760 "sink pads_activate failed");
2765 /* is called with STATE_LOCK */
2766 static GstStateChangeReturn
2767 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2769 GstState state, next;
2770 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2772 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2774 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2775 next = GST_STATE_TRANSITION_NEXT (transition);
2777 /* if the element already is in the given state, we just return success */
2778 if (next == GST_STATE_VOID_PENDING || state == next)
2781 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2782 "default handler tries setting state from %s to %s (%04x)",
2783 gst_element_state_get_name (state),
2784 gst_element_state_get_name (next), transition);
2786 switch (transition) {
2787 case GST_STATE_CHANGE_NULL_TO_READY:
2789 case GST_STATE_CHANGE_READY_TO_PAUSED:
2790 if (!gst_element_pads_activate (element, TRUE)) {
2791 result = GST_STATE_CHANGE_FAILURE;
2794 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2796 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2798 case GST_STATE_CHANGE_PAUSED_TO_READY:
2799 case GST_STATE_CHANGE_READY_TO_NULL:
2800 /* deactivate pads in both cases, since they are activated on
2801 ready->paused but the element might not have made it to paused */
2802 if (!gst_element_pads_activate (element, FALSE)) {
2803 result = GST_STATE_CHANGE_FAILURE;
2807 /* this will catch real but unhandled state changes;
2808 * can only be caused by:
2809 * - a new state was added
2810 * - somehow the element was asked to jump across an intermediate state
2812 g_warning ("Unhandled state change from %s to %s",
2813 gst_element_state_get_name (state),
2814 gst_element_state_get_name (next));
2821 GST_OBJECT_LOCK (element);
2822 result = GST_STATE_RETURN (element);
2823 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2824 "element is already in the %s state",
2825 gst_element_state_get_name (state));
2826 GST_OBJECT_UNLOCK (element);
2833 * gst_element_get_factory:
2834 * @element: a #GstElement to request the element factory of.
2836 * Retrieves the factory that was used to create this element.
2838 * Returns: (transfer none): the #GstElementFactory used for creating this
2839 * element. no refcounting is needed.
2842 gst_element_get_factory (GstElement * element)
2844 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2846 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2850 gst_element_dispose (GObject * object)
2852 GstElement *element = GST_ELEMENT_CAST (object);
2856 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2858 if (GST_STATE (element) != GST_STATE_NULL)
2861 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2862 "removing %d pads", g_list_length (element->pads));
2863 /* first we break all our links with the outside */
2864 while (element->pads && element->pads->data) {
2865 /* don't call _remove_pad with NULL */
2866 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2868 if (G_UNLIKELY (element->pads != NULL)) {
2869 g_critical ("could not remove pads from element %s",
2870 GST_STR_NULL (GST_OBJECT_NAME (object)));
2873 GST_OBJECT_LOCK (element);
2874 clock_p = &element->clock;
2875 bus_p = &element->bus;
2876 gst_object_replace ((GstObject **) clock_p, NULL);
2877 gst_object_replace ((GstObject **) bus_p, NULL);
2878 GST_OBJECT_UNLOCK (element);
2880 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2882 G_OBJECT_CLASS (parent_class)->dispose (object);
2891 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2893 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2895 "You need to explicitly set elements to the NULL state before\n"
2896 "dropping the final reference, to allow them to clean up.\n"
2897 "This problem may also be caused by a refcounting bug in the\n"
2898 "application or some element.\n",
2899 GST_OBJECT_NAME (element),
2900 gst_element_state_get_name (GST_STATE (element)),
2901 is_locked ? " (locked)" : "");
2907 gst_element_finalize (GObject * object)
2909 GstElement *element = GST_ELEMENT_CAST (object);
2911 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2913 g_cond_free (element->state_cond);
2914 g_static_rec_mutex_free (&element->state_lock);
2916 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2918 G_OBJECT_CLASS (parent_class)->finalize (object);
2922 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2926 g_return_if_fail (GST_IS_ELEMENT (element));
2928 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2930 GST_OBJECT_LOCK (element);
2931 bus_p = &GST_ELEMENT_BUS (element);
2932 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2933 GST_OBJECT_UNLOCK (element);
2937 * gst_element_set_bus:
2938 * @element: a #GstElement to set the bus of.
2939 * @bus: (transfer none): the #GstBus to set.
2941 * Sets the bus of the element. Increases the refcount on the bus.
2942 * For internal use only, unless you're testing elements.
2947 gst_element_set_bus (GstElement * element, GstBus * bus)
2949 GstElementClass *oclass;
2951 g_return_if_fail (GST_IS_ELEMENT (element));
2953 oclass = GST_ELEMENT_GET_CLASS (element);
2955 if (oclass->set_bus)
2956 oclass->set_bus (element, bus);
2960 * gst_element_get_bus:
2961 * @element: a #GstElement to get the bus of.
2963 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2964 * bus for the application.
2966 * Returns: (transfer full): the element's #GstBus. unref after usage.
2971 gst_element_get_bus (GstElement * element)
2973 GstBus *result = NULL;
2975 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2977 GST_OBJECT_LOCK (element);
2978 if ((result = GST_ELEMENT_BUS (element)))
2979 gst_object_ref (result);
2980 GST_OBJECT_UNLOCK (element);
2982 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,