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 /* FIXME 0.11: Store this directly in the instance struct */
288 g_static_rec_mutex_init (&element->state_lock);
289 element->state_cond = g_cond_new ();
293 * gst_element_release_request_pad:
294 * @element: a #GstElement to release the request pad of.
295 * @pad: the #GstPad to release.
297 * Makes the element free the previously requested pad as obtained
298 * with gst_element_get_request_pad().
300 * This does not unref the pad. If the pad was created by using
301 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
302 * followed by gst_object_unref() to free the @pad.
307 gst_element_release_request_pad (GstElement * element, GstPad * pad)
309 GstElementClass *oclass;
311 g_return_if_fail (GST_IS_ELEMENT (element));
312 g_return_if_fail (GST_IS_PAD (pad));
314 oclass = GST_ELEMENT_GET_CLASS (element);
316 /* if the element implements a custom release function we call that, else we
317 * simply remove the pad from the element */
318 if (oclass->release_pad)
319 (oclass->release_pad) (element, pad);
321 gst_element_remove_pad (element, pad);
325 * gst_element_requires_clock:
326 * @element: a #GstElement to query
328 * Query if the element requires a clock.
330 * Returns: %TRUE if the element requires a clock
335 gst_element_requires_clock (GstElement * element)
339 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
341 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
347 * gst_element_provides_clock:
348 * @element: a #GstElement to query
350 * Query if the element provides a clock. A #GstClock provided by an
351 * element can be used as the global #GstClock for the pipeline.
352 * An element that can provide a clock is only required to do so in the PAUSED
353 * state, this means when it is fully negotiated and has allocated the resources
354 * to operate the clock.
356 * Returns: %TRUE if the element provides a clock
361 gst_element_provides_clock (GstElement * element)
365 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
367 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
373 * gst_element_provide_clock:
374 * @element: a #GstElement to query
376 * Get the clock provided by the given element.
377 * <note>An element is only required to provide a clock in the PAUSED
378 * state. Some elements can provide a clock in other states.</note>
380 * Returns: (transfer full): the GstClock provided by the element or %NULL
381 * if no clock could be provided. Unref after usage.
386 gst_element_provide_clock (GstElement * element)
388 GstClock *result = NULL;
389 GstElementClass *oclass;
391 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
393 oclass = GST_ELEMENT_GET_CLASS (element);
395 if (oclass->provide_clock)
396 result = oclass->provide_clock (element);
402 * gst_element_set_clock:
403 * @element: a #GstElement to set the clock for.
404 * @clock: the #GstClock to set for the element.
406 * Sets the clock for the element. This function increases the
407 * refcount on the clock. Any previously set clock on the object
410 * Returns: %TRUE if the element accepted the clock. An element can refuse a
411 * clock when it, for example, is not able to slave its internal clock to the
412 * @clock or when it requires a specific clock to operate.
417 gst_element_set_clock (GstElement * element, GstClock * clock)
419 GstElementClass *oclass;
423 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
424 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
426 oclass = GST_ELEMENT_GET_CLASS (element);
428 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
430 if (oclass->set_clock)
431 res = oclass->set_clock (element, clock);
434 /* only update the clock pointer if the element accepted the clock */
435 GST_OBJECT_LOCK (element);
436 clock_p = &element->clock;
437 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
438 GST_OBJECT_UNLOCK (element);
444 * gst_element_get_clock:
445 * @element: a #GstElement to get the clock of.
447 * Gets the currently configured clock of the element. This is the clock as was
448 * last set with gst_element_set_clock().
450 * Returns: (transfer full): the #GstClock of the element. unref after usage.
455 gst_element_get_clock (GstElement * element)
459 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
461 GST_OBJECT_LOCK (element);
462 if ((result = element->clock))
463 gst_object_ref (result);
464 GST_OBJECT_UNLOCK (element);
470 * gst_element_set_base_time:
471 * @element: a #GstElement.
472 * @time: the base time to set.
474 * Set the base time of an element. See gst_element_get_base_time().
479 gst_element_set_base_time (GstElement * element, GstClockTime time)
483 g_return_if_fail (GST_IS_ELEMENT (element));
485 GST_OBJECT_LOCK (element);
486 old = element->base_time;
487 element->base_time = time;
488 GST_OBJECT_UNLOCK (element);
490 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
491 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
492 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
496 * gst_element_get_base_time:
497 * @element: a #GstElement.
499 * Returns the base time of the element. The base time is the
500 * absolute time of the clock when this element was last put to
501 * PLAYING. Subtracting the base time from the clock time gives
502 * the running time of the element.
504 * Returns: the base time of the element.
509 gst_element_get_base_time (GstElement * element)
513 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
515 GST_OBJECT_LOCK (element);
516 result = element->base_time;
517 GST_OBJECT_UNLOCK (element);
523 * gst_element_set_start_time:
524 * @element: a #GstElement.
525 * @time: the base time to set.
527 * Set the start time of an element. The start time of the element is the
528 * running time of the element when it last went to the PAUSED state. In READY
529 * or after a flushing seek, it is set to 0.
531 * Toplevel elements like #GstPipeline will manage the start_time and
532 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
533 * on such a toplevel element will disable the distribution of the base_time to
534 * the children and can be useful if the application manages the base_time
535 * itself, for example if you want to synchronize capture from multiple
536 * pipelines, and you can also ensure that the pipelines have the same clock.
543 gst_element_set_start_time (GstElement * element, GstClockTime time)
547 g_return_if_fail (GST_IS_ELEMENT (element));
549 GST_OBJECT_LOCK (element);
550 old = GST_ELEMENT_START_TIME (element);
551 GST_ELEMENT_START_TIME (element) = time;
552 GST_OBJECT_UNLOCK (element);
554 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
555 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
556 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
560 * gst_element_get_start_time:
561 * @element: a #GstElement.
563 * Returns the start time of the element. The start time is the
564 * running time of the clock when this element was last put to PAUSED.
566 * Usually the start_time is managed by a toplevel element such as
571 * Returns: the start time of the element.
576 gst_element_get_start_time (GstElement * element)
580 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
582 GST_OBJECT_LOCK (element);
583 result = GST_ELEMENT_START_TIME (element);
584 GST_OBJECT_UNLOCK (element);
590 * gst_element_is_indexable:
591 * @element: a #GstElement.
593 * Queries if the element can be indexed.
595 * Returns: TRUE if the element can be indexed.
600 gst_element_is_indexable (GstElement * element)
604 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
606 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
612 * gst_element_set_index:
613 * @element: a #GstElement.
614 * @index: (transfer none): a #GstIndex.
616 * Set @index on the element. The refcount of the index
617 * will be increased, any previously set index is unreffed.
622 gst_element_set_index (GstElement * element, GstIndex * index)
624 GstElementClass *oclass;
626 g_return_if_fail (GST_IS_ELEMENT (element));
627 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
629 oclass = GST_ELEMENT_GET_CLASS (element);
631 if (oclass->set_index)
632 oclass->set_index (element, index);
636 * gst_element_get_index:
637 * @element: a #GstElement.
639 * Gets the index from the element.
641 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
642 * element. unref after usage.
647 gst_element_get_index (GstElement * element)
649 GstElementClass *oclass;
650 GstIndex *result = NULL;
652 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
654 oclass = GST_ELEMENT_GET_CLASS (element);
656 if (oclass->get_index)
657 result = oclass->get_index (element);
663 * gst_element_add_pad:
664 * @element: a #GstElement to add the pad to.
665 * @pad: (transfer full): the #GstPad to add to the element.
667 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
668 * see gst_object_set_parent() for refcounting information.
670 * Pads are not automatically activated so elements should perform the needed
671 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
672 * state. See gst_pad_set_active() for more information about activating pads.
674 * The pad and the element should be unlocked when calling this function.
676 * This function will emit the #GstElement::pad-added signal on the element.
678 * Returns: %TRUE if the pad could be added. This function can fail when
679 * a pad with the same name already existed or the pad already had another
685 gst_element_add_pad (GstElement * element, GstPad * pad)
690 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
691 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
693 /* locking pad to look at the name */
694 GST_OBJECT_LOCK (pad);
695 pad_name = g_strdup (GST_PAD_NAME (pad));
696 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
697 GST_STR_NULL (pad_name));
698 flushing = GST_PAD_IS_FLUSHING (pad);
699 GST_OBJECT_UNLOCK (pad);
701 /* then check to see if there's already a pad by that name here */
702 GST_OBJECT_LOCK (element);
703 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
706 /* try to set the pad's parent */
707 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
708 GST_OBJECT_CAST (element))))
711 /* check for flushing pads */
712 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
713 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
714 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
715 "use gst_pad_set_active(pad,TRUE) before adding it.",
716 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
718 GST_OBJECT_LOCK (pad);
719 GST_PAD_UNSET_FLUSHING (pad);
720 GST_OBJECT_UNLOCK (pad);
725 /* add it to the list */
726 switch (gst_pad_get_direction (pad)) {
728 element->srcpads = g_list_prepend (element->srcpads, pad);
729 element->numsrcpads++;
732 element->sinkpads = g_list_prepend (element->sinkpads, pad);
733 element->numsinkpads++;
738 element->pads = g_list_prepend (element->pads, pad);
740 element->pads_cookie++;
741 GST_OBJECT_UNLOCK (element);
743 /* emit the PAD_ADDED signal */
744 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
751 g_critical ("Padname %s is not unique in element %s, not adding",
752 pad_name, GST_ELEMENT_NAME (element));
753 GST_OBJECT_UNLOCK (element);
760 ("Pad %s already has parent when trying to add to element %s",
761 pad_name, GST_ELEMENT_NAME (element));
762 GST_OBJECT_UNLOCK (element);
768 GST_OBJECT_LOCK (pad);
770 ("Trying to add pad %s to element %s, but it has no direction",
771 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
772 GST_OBJECT_UNLOCK (pad);
773 GST_OBJECT_UNLOCK (element);
779 * gst_element_remove_pad:
780 * @element: a #GstElement to remove pad from.
781 * @pad: (transfer none): the #GstPad to remove from the element.
783 * Removes @pad from @element. @pad will be destroyed if it has not been
784 * referenced elsewhere using gst_object_unparent().
786 * This function is used by plugin developers and should not be used
787 * by applications. Pads that were dynamically requested from elements
788 * with gst_element_get_request_pad() should be released with the
789 * gst_element_release_request_pad() function instead.
791 * Pads are not automatically deactivated so elements should perform the needed
792 * steps to deactivate the pad in case this pad is removed in the PAUSED or
793 * PLAYING state. See gst_pad_set_active() for more information about
796 * The pad and the element should be unlocked when calling this function.
798 * This function will emit the #GstElement::pad-removed signal on the element.
800 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
801 * pad does not belong to the provided element.
806 gst_element_remove_pad (GstElement * element, GstPad * pad)
810 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
811 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
813 /* locking pad to look at the name and parent */
814 GST_OBJECT_LOCK (pad);
815 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
816 GST_STR_NULL (GST_PAD_NAME (pad)));
818 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
820 GST_OBJECT_UNLOCK (pad);
823 if ((peer = gst_pad_get_peer (pad))) {
824 /* window for MT unsafeness, someone else could unlink here
825 * and then we call unlink with wrong pads. The unlink
826 * function would catch this and safely return failed. */
827 if (GST_PAD_IS_SRC (pad))
828 gst_pad_unlink (pad, peer);
830 gst_pad_unlink (peer, pad);
832 gst_object_unref (peer);
835 GST_OBJECT_LOCK (element);
836 /* remove it from the list */
837 switch (gst_pad_get_direction (pad)) {
839 element->srcpads = g_list_remove (element->srcpads, pad);
840 element->numsrcpads--;
843 element->sinkpads = g_list_remove (element->sinkpads, pad);
844 element->numsinkpads--;
847 g_critical ("Removing pad without direction???");
850 element->pads = g_list_remove (element->pads, pad);
852 element->pads_cookie++;
853 GST_OBJECT_UNLOCK (element);
855 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
856 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
858 gst_object_unparent (GST_OBJECT_CAST (pad));
865 /* FIXME, locking order? */
866 GST_OBJECT_LOCK (element);
867 g_critical ("Padname %s:%s does not belong to element %s when removing",
868 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
869 GST_OBJECT_UNLOCK (element);
870 GST_OBJECT_UNLOCK (pad);
876 * gst_element_no_more_pads:
877 * @element: a #GstElement
879 * Use this function to signal that the element does not expect any more pads
880 * to show up in the current pipeline. This function should be called whenever
881 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
882 * pad templates use this in combination with autopluggers to figure out that
883 * the element is done initializing its pads.
885 * This function emits the #GstElement::no-more-pads signal.
890 gst_element_no_more_pads (GstElement * element)
892 g_return_if_fail (GST_IS_ELEMENT (element));
894 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
898 pad_compare_name (GstPad * pad1, const gchar * name)
902 GST_OBJECT_LOCK (pad1);
903 result = strcmp (GST_PAD_NAME (pad1), name);
904 GST_OBJECT_UNLOCK (pad1);
910 * gst_element_get_static_pad:
911 * @element: a #GstElement to find a static pad of.
912 * @name: the name of the static #GstPad to retrieve.
914 * Retrieves a pad from @element by name. This version only retrieves
915 * already-existing (i.e. 'static') pads.
917 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
923 gst_element_get_static_pad (GstElement * element, const gchar * name)
926 GstPad *result = NULL;
928 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
929 g_return_val_if_fail (name != NULL, NULL);
931 GST_OBJECT_LOCK (element);
933 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
935 result = GST_PAD_CAST (find->data);
936 gst_object_ref (result);
939 if (result == NULL) {
940 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
941 name, GST_ELEMENT_NAME (element));
943 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
944 GST_ELEMENT_NAME (element), name);
946 GST_OBJECT_UNLOCK (element);
952 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
953 const gchar * name, const GstCaps * caps)
955 GstPad *newpad = NULL;
956 GstElementClass *oclass;
958 oclass = GST_ELEMENT_GET_CLASS (element);
960 #ifndef G_DISABLE_CHECKS
961 /* Some sanity checking here */
965 /* Is this the template name? */
966 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
967 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
969 const gchar *str, *data;
972 /* Otherwise check if it's a valid name for the name template */
973 str = strchr (templ->name_template, '%');
974 g_return_val_if_fail (str != NULL, NULL);
975 g_return_val_if_fail (strncmp (templ->name_template, name,
976 str - templ->name_template) == 0, NULL);
977 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
979 data = name + (str - templ->name_template);
981 /* Can either be %s or %d or %u, do sanity checking for %d */
982 if (*(str + 1) == 'd') {
986 tmp = g_ascii_strtoll (data, &endptr, 10);
987 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
988 && *endptr == '\0', NULL);
989 } else if (*(str + 1) == 'u') {
993 tmp = g_ascii_strtoull (data, &endptr, 10);
994 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
998 pad = gst_element_get_static_pad (element, name);
1000 gst_object_unref (pad);
1001 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1002 g_critical ("Element %s already has a pad named %s, the behaviour of "
1003 " gst_element_get_request_pad() for existing pads is undefined!",
1004 GST_ELEMENT_NAME (element), name);
1009 if (oclass->request_new_pad)
1010 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1013 gst_object_ref (newpad);
1019 * gst_element_get_request_pad:
1020 * @element: a #GstElement to find a request pad of.
1021 * @name: the name of the request #GstPad to retrieve.
1023 * Retrieves a pad from the element by name. This version only retrieves
1024 * request pads. The pad should be released with
1025 * gst_element_release_request_pad().
1027 * This method is slow and will be deprecated in the future. New code should
1028 * use gst_element_request_pad() with the requested template.
1030 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1031 * Release after usage.
1034 gst_element_get_request_pad (GstElement * element, const gchar * name)
1036 GstPadTemplate *templ = NULL;
1038 const gchar *req_name = NULL;
1039 gboolean templ_found = FALSE;
1042 gchar *str, *endptr = NULL;
1043 GstElementClass *class;
1045 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1046 g_return_val_if_fail (name != NULL, NULL);
1048 class = GST_ELEMENT_GET_CLASS (element);
1050 /* if the name contains a %, we assume it's the complete template name. Get
1051 * the template and try to get a pad */
1052 if (strstr (name, "%")) {
1053 templ = gst_element_class_get_request_pad_template (class, name);
1058 /* there is no % in the name, try to find a matching template */
1059 list = class->padtemplates;
1060 while (!templ_found && list) {
1061 templ = (GstPadTemplate *) list->data;
1062 if (templ->presence == GST_PAD_REQUEST) {
1063 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1064 templ->name_template);
1065 /* see if we find an exact match */
1066 if (strcmp (name, templ->name_template) == 0) {
1071 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1072 and %d and %u, occurring at the end of the name_template, are the only
1074 else if ((str = strchr (templ->name_template, '%'))
1075 && strncmp (templ->name_template, name,
1076 str - templ->name_template) == 0
1077 && strlen (name) > str - templ->name_template) {
1078 data = name + (str - templ->name_template);
1079 if (*(str + 1) == 'd') {
1083 tmp = strtol (data, &endptr, 10);
1084 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1090 } else if (*(str + 1) == 'u') {
1094 tmp = strtoul (data, &endptr, 10);
1095 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1115 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1121 * gst_element_request_pad:
1122 * @element: a #GstElement to find a request pad of.
1123 * @templ: a #GstPadTemplate of which we want a pad of.
1124 * @name: (transfer none) (allow-none): the name of the request #GstPad
1125 * to retrieve. Can be %NULL.
1126 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1127 * request. Can be %NULL.
1129 * Retrieves a request pad from the element according to the provided template.
1131 * If the @caps are specified and the element implements thew new
1132 * request_new_pad_full virtual method, the element will use them to select
1133 * which pad to create.
1135 * The pad should be released with gst_element_release_request_pad().
1137 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1138 * Release after usage.
1143 gst_element_request_pad (GstElement * element,
1144 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1146 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1147 g_return_val_if_fail (templ != NULL, NULL);
1149 return _gst_element_request_pad (element, templ, name, caps);
1152 static GstIterator *
1153 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1155 GstIterator *result;
1157 GST_OBJECT_LOCK (element);
1158 result = gst_iterator_new_list (GST_TYPE_PAD,
1159 GST_OBJECT_GET_LOCK (element),
1160 &element->pads_cookie, padlist, (GObject *) element, NULL);
1161 GST_OBJECT_UNLOCK (element);
1167 * gst_element_iterate_pads:
1168 * @element: a #GstElement to iterate pads of.
1170 * Retrieves an iterattor of @element's pads. The iterator should
1171 * be freed after usage.
1173 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1179 gst_element_iterate_pads (GstElement * element)
1181 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1183 return gst_element_iterate_pad_list (element, &element->pads);
1187 * gst_element_iterate_src_pads:
1188 * @element: a #GstElement.
1190 * Retrieves an iterator of @element's source pads.
1192 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1198 gst_element_iterate_src_pads (GstElement * element)
1200 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1202 return gst_element_iterate_pad_list (element, &element->srcpads);
1206 * gst_element_iterate_sink_pads:
1207 * @element: a #GstElement.
1209 * Retrieves an iterator of @element's sink pads.
1211 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1217 gst_element_iterate_sink_pads (GstElement * element)
1219 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1221 return gst_element_iterate_pad_list (element, &element->sinkpads);
1225 * gst_element_class_add_pad_template:
1226 * @klass: the #GstElementClass to add the pad template to.
1227 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1229 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1230 * functions of classes. If a pad template with the same name as an already
1231 * existing one is added the old one is replaced by the new one.
1235 gst_element_class_add_pad_template (GstElementClass * klass,
1236 GstPadTemplate * templ)
1238 GList *template_list = klass->padtemplates;
1240 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1241 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1243 /* If we already have a pad template with the same name replace the
1245 while (template_list) {
1246 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1248 /* Found pad with the same name, replace and return */
1249 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1250 gst_object_unref (padtempl);
1251 template_list->data = templ;
1254 template_list = g_list_next (template_list);
1257 /* Take ownership of the floating ref */
1258 g_object_ref_sink (templ);
1260 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1261 klass->numpadtemplates++;
1265 * gst_element_class_add_metadata:
1266 * @klass: class to set metadata for
1267 * @key: the key to set
1268 * @value: the value to set
1270 * Set @key with @value as metadata in @klass.
1273 gst_element_class_add_metadata (GstElementClass * klass,
1274 const gchar * key, const gchar * value)
1276 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1277 g_return_if_fail (key != NULL);
1278 g_return_if_fail (value != NULL);
1280 gst_structure_set ((GstStructure *) klass->metadata,
1281 key, G_TYPE_STRING, value, NULL);
1285 * gst_element_class_set_metadata:
1286 * @klass: class to set metadata for
1287 * @longname: The long English name of the element. E.g. "File Sink"
1288 * @classification: String describing the type of element, as an unordered list
1289 * separated with slashes ('/'). See draft-klass.txt of the design docs
1290 * for more details and common types. E.g: "Sink/File"
1291 * @description: Sentence describing the purpose of the element.
1292 * E.g: "Write stream to a file"
1293 * @author: Name and contact details of the author(s). Use \n to separate
1294 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1296 * Sets the detailed information for a #GstElementClass.
1297 * <note>This function is for use in _class_init functions only.</note>
1300 gst_element_class_set_metadata (GstElementClass * klass,
1301 const gchar * longname, const gchar * classification,
1302 const gchar * description, const gchar * author)
1304 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1306 gst_structure_set ((GstStructure *) klass->metadata,
1307 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1308 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1309 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1310 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1314 * gst_element_class_get_metadata:
1315 * @klass: class to get metadata for
1316 * @key: the key to get
1318 * Get metadata with @key in @klass.
1320 * Returns: the metadata for @key.
1322 G_CONST_RETURN gchar *
1323 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1325 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1326 g_return_val_if_fail (key != NULL, NULL);
1328 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1332 * gst_element_class_get_pad_template_list:
1333 * @element_class: a #GstElementClass to get pad templates of.
1335 * Retrieves a list of the pad templates associated with @element_class. The
1336 * list must not be modified by the calling code.
1337 * <note>If you use this function in the #GInstanceInitFunc of an object class
1338 * that has subclasses, make sure to pass the g_class parameter of the
1339 * #GInstanceInitFunc here.</note>
1341 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1345 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1347 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1349 return element_class->padtemplates;
1353 * gst_element_class_get_pad_template:
1354 * @element_class: a #GstElementClass to get the pad template of.
1355 * @name: the name of the #GstPadTemplate to get.
1357 * Retrieves a padtemplate from @element_class with the given name.
1358 * <note>If you use this function in the #GInstanceInitFunc of an object class
1359 * that has subclasses, make sure to pass the g_class parameter of the
1360 * #GInstanceInitFunc here.</note>
1362 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1363 * if none was found. No unreferencing is necessary.
1366 gst_element_class_get_pad_template (GstElementClass *
1367 element_class, const gchar * name)
1371 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1372 g_return_val_if_fail (name != NULL, NULL);
1374 padlist = element_class->padtemplates;
1377 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1379 if (strcmp (padtempl->name_template, name) == 0)
1382 padlist = g_list_next (padlist);
1388 static GstPadTemplate *
1389 gst_element_class_get_request_pad_template (GstElementClass *
1390 element_class, const gchar * name)
1392 GstPadTemplate *tmpl;
1394 tmpl = gst_element_class_get_pad_template (element_class, name);
1395 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1401 /* get a random pad on element of the given direction.
1402 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1405 gst_element_get_random_pad (GstElement * element,
1406 gboolean need_linked, GstPadDirection dir)
1408 GstPad *result = NULL;
1411 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1415 GST_OBJECT_LOCK (element);
1416 pads = element->srcpads;
1419 GST_OBJECT_LOCK (element);
1420 pads = element->sinkpads;
1423 goto wrong_direction;
1425 for (; pads; pads = g_list_next (pads)) {
1426 GstPad *pad = GST_PAD_CAST (pads->data);
1428 GST_OBJECT_LOCK (pad);
1429 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1430 GST_DEBUG_PAD_NAME (pad));
1432 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1433 /* if we require a linked pad, and it is not linked, continue the
1435 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1436 GST_DEBUG_PAD_NAME (pad));
1437 GST_OBJECT_UNLOCK (pad);
1440 /* found a pad, stop search */
1441 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1442 GST_DEBUG_PAD_NAME (pad));
1443 GST_OBJECT_UNLOCK (pad);
1449 gst_object_ref (result);
1451 GST_OBJECT_UNLOCK (element);
1455 /* ERROR handling */
1458 g_warning ("unknown pad direction %d", dir);
1464 gst_element_default_send_event (GstElement * element, GstEvent * event)
1466 gboolean result = FALSE;
1469 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1470 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1471 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1474 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1475 "pushing %s event to random %s pad %s:%s",
1476 GST_EVENT_TYPE_NAME (event),
1477 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1478 GST_DEBUG_PAD_NAME (pad));
1480 result = gst_pad_push_event (pad, event);
1481 gst_object_unref (pad);
1483 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1484 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1485 gst_event_unref (event);
1491 * gst_element_send_event:
1492 * @element: a #GstElement to send the event to.
1493 * @event: (transfer full): the #GstEvent to send to the element.
1495 * Sends an event to an element. If the element doesn't implement an
1496 * event handler, the event will be pushed on a random linked sink pad for
1497 * upstream events or a random linked source pad for downstream events.
1499 * This function takes owership of the provided event so you should
1500 * gst_event_ref() it if you want to reuse the event after this call.
1502 * Returns: %TRUE if the event was handled.
1507 gst_element_send_event (GstElement * element, GstEvent * event)
1509 GstElementClass *oclass;
1510 gboolean result = FALSE;
1512 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1513 g_return_val_if_fail (event != NULL, FALSE);
1515 oclass = GST_ELEMENT_GET_CLASS (element);
1517 GST_STATE_LOCK (element);
1518 if (oclass->send_event) {
1519 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1520 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1521 result = oclass->send_event (element, event);
1523 result = gst_element_default_send_event (element, event);
1525 GST_STATE_UNLOCK (element);
1532 * @element: a #GstElement to send the event to.
1533 * @rate: The new playback rate
1534 * @format: The format of the seek values
1535 * @flags: The optional seek flags.
1536 * @cur_type: The type and flags for the new current position
1537 * @cur: The value of the new current position
1538 * @stop_type: The type and flags for the new stop position
1539 * @stop: The value of the new stop position
1541 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1542 * the parameters. The seek event is sent to the element using
1543 * gst_element_send_event().
1545 * Returns: %TRUE if the event was handled.
1550 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1551 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1552 GstSeekType stop_type, gint64 stop)
1557 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1560 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1561 result = gst_element_send_event (element, event);
1567 * gst_element_get_query_types:
1568 * @element: a #GstElement to query
1570 * Get an array of query types from the element.
1571 * If the element doesn't implement a query types function,
1572 * the query will be forwarded to the peer of a random linked sink pad.
1574 * Returns: An array of #GstQueryType elements that should not
1575 * be freed or modified.
1579 const GstQueryType *
1580 gst_element_get_query_types (GstElement * element)
1582 GstElementClass *oclass;
1583 const GstQueryType *result = NULL;
1585 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1587 oclass = GST_ELEMENT_GET_CLASS (element);
1589 if (oclass->get_query_types) {
1590 result = oclass->get_query_types (element);
1592 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1595 GstPad *peer = gst_pad_get_peer (pad);
1598 result = gst_pad_get_query_types (peer);
1600 gst_object_unref (peer);
1602 gst_object_unref (pad);
1609 gst_element_default_query (GstElement * element, GstQuery * query)
1611 gboolean result = FALSE;
1614 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1616 result = gst_pad_query (pad, query);
1618 gst_object_unref (pad);
1620 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1622 GstPad *peer = gst_pad_get_peer (pad);
1625 result = gst_pad_query (peer, query);
1627 gst_object_unref (peer);
1629 gst_object_unref (pad);
1636 * gst_element_query:
1637 * @element: a #GstElement to perform the query on.
1638 * @query: (transfer none): the #GstQuery.
1640 * Performs a query on the given element.
1642 * For elements that don't implement a query handler, this function
1643 * forwards the query to a random srcpad or to the peer of a
1644 * random linked sinkpad of this element.
1646 * Please note that some queries might need a running pipeline to work.
1648 * Returns: TRUE if the query could be performed.
1653 gst_element_query (GstElement * element, GstQuery * query)
1655 GstElementClass *oclass;
1656 gboolean result = FALSE;
1658 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1659 g_return_val_if_fail (query != NULL, FALSE);
1661 oclass = GST_ELEMENT_GET_CLASS (element);
1663 if (oclass->query) {
1664 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1665 GST_ELEMENT_NAME (element));
1666 result = oclass->query (element, query);
1668 result = gst_element_default_query (element, query);
1674 * gst_element_post_message:
1675 * @element: a #GstElement posting the message
1676 * @message: (transfer full): a #GstMessage to post
1678 * Post a message on the element's #GstBus. This function takes ownership of the
1679 * message; if you want to access the message after this call, you should add an
1680 * additional reference before calling.
1682 * Returns: %TRUE if the message was successfully posted. The function returns
1683 * %FALSE if the element did not have a bus.
1688 gst_element_post_message (GstElement * element, GstMessage * message)
1691 gboolean result = FALSE;
1693 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1694 g_return_val_if_fail (message != NULL, FALSE);
1696 GST_OBJECT_LOCK (element);
1699 if (G_UNLIKELY (bus == NULL))
1702 gst_object_ref (bus);
1703 GST_OBJECT_UNLOCK (element);
1705 /* we release the element lock when posting the message so that any
1706 * (synchronous) message handlers can operate on the element */
1707 result = gst_bus_post (bus, message);
1708 gst_object_unref (bus);
1715 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1716 "not posting message %p: no bus", message);
1717 GST_OBJECT_UNLOCK (element);
1718 gst_message_unref (message);
1724 * _gst_element_error_printf:
1725 * @format: the printf-like format to use, or %NULL
1727 * This function is only used internally by the gst_element_error() macro.
1729 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1735 _gst_element_error_printf (const gchar * format, ...)
1745 va_start (args, format);
1746 buffer = g_strdup_vprintf (format, args);
1752 * gst_element_message_full:
1753 * @element: a #GstElement to send message from
1754 * @type: the #GstMessageType
1755 * @domain: the GStreamer GError domain this message belongs to
1756 * @code: the GError code belonging to the domain
1757 * @text: (allow-none) (transfer full): an allocated text string to be used
1758 * as a replacement for the default message connected to code,
1760 * @debug: (allow-none) (transfer full): an allocated debug message to be
1761 * used as a replacement for the default debugging information,
1763 * @file: the source code file where the error was generated
1764 * @function: the source code function where the error was generated
1765 * @line: the source code line where the error was generated
1767 * Post an error, warning or info message on the bus from inside an element.
1769 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1770 * #GST_MESSAGE_INFO.
1774 void gst_element_message_full
1775 (GstElement * element, GstMessageType type,
1776 GQuark domain, gint code, gchar * text,
1777 gchar * debug, const gchar * file, const gchar * function, gint line)
1779 GError *gerror = NULL;
1783 gboolean has_debug = TRUE;
1784 GstMessage *message = NULL;
1787 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1788 g_return_if_fail (GST_IS_ELEMENT (element));
1789 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1790 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1792 /* check if we send the given text or the default error text */
1793 if ((text == NULL) || (text[0] == 0)) {
1794 /* text could have come from g_strdup_printf (""); */
1796 sent_text = gst_error_get_message (domain, code);
1800 /* construct a sent_debug with extra information from source */
1801 if ((debug == NULL) || (debug[0] == 0)) {
1802 /* debug could have come from g_strdup_printf (""); */
1806 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1808 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1809 file, line, function, name, debug);
1811 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1812 file, line, function, name);
1816 /* create gerror and post message */
1817 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1819 gerror = g_error_new_literal (domain, code, sent_text);
1822 case GST_MESSAGE_ERROR:
1824 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1826 case GST_MESSAGE_WARNING:
1827 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1830 case GST_MESSAGE_INFO:
1831 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1835 g_assert_not_reached ();
1838 gst_element_post_message (element, message);
1840 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1841 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1844 g_error_free (gerror);
1845 g_free (sent_debug);
1850 * gst_element_is_locked_state:
1851 * @element: a #GstElement.
1853 * Checks if the state of an element is locked.
1854 * If the state of an element is locked, state changes of the parent don't
1855 * affect the element.
1856 * This way you can leave currently unused elements inside bins. Just lock their
1857 * state before changing the state from #GST_STATE_NULL.
1861 * Returns: TRUE, if the element's state is locked.
1864 gst_element_is_locked_state (GstElement * element)
1868 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1870 GST_OBJECT_LOCK (element);
1871 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1872 GST_OBJECT_UNLOCK (element);
1878 * gst_element_set_locked_state:
1879 * @element: a #GstElement
1880 * @locked_state: TRUE to lock the element's state
1882 * Locks the state of an element, so state changes of the parent don't affect
1883 * this element anymore.
1887 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1888 * or the elements state-locking needed no change.
1891 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1895 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1897 GST_OBJECT_LOCK (element);
1898 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1900 if (G_UNLIKELY (old == locked_state))
1904 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1905 GST_ELEMENT_NAME (element));
1906 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1908 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1909 GST_ELEMENT_NAME (element));
1910 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1912 GST_OBJECT_UNLOCK (element);
1918 GST_CAT_DEBUG (GST_CAT_STATES,
1919 "elements %s was already in locked state %d",
1920 GST_ELEMENT_NAME (element), old);
1921 GST_OBJECT_UNLOCK (element);
1928 * gst_element_sync_state_with_parent:
1929 * @element: a #GstElement.
1931 * Tries to change the state of the element to the same as its parent.
1932 * If this function returns FALSE, the state of element is undefined.
1934 * Returns: TRUE, if the element's state could be synced to the parent's state.
1939 gst_element_sync_state_with_parent (GstElement * element)
1943 GstStateChangeReturn ret;
1945 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1947 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1948 GstState parent_current, parent_pending;
1950 GST_OBJECT_LOCK (parent);
1951 parent_current = GST_STATE (parent);
1952 parent_pending = GST_STATE_PENDING (parent);
1953 GST_OBJECT_UNLOCK (parent);
1955 /* set to pending if there is one, else we set it to the current state of
1957 if (parent_pending != GST_STATE_VOID_PENDING)
1958 target = parent_pending;
1960 target = parent_current;
1962 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1963 "syncing state (%s) to parent %s %s (%s, %s)",
1964 gst_element_state_get_name (GST_STATE (element)),
1965 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1966 gst_element_state_get_name (parent_current),
1967 gst_element_state_get_name (parent_pending));
1969 ret = gst_element_set_state (element, target);
1970 if (ret == GST_STATE_CHANGE_FAILURE)
1973 gst_object_unref (parent);
1977 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1984 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1985 "syncing state failed (%s)",
1986 gst_element_state_change_return_get_name (ret));
1987 gst_object_unref (parent);
1993 static GstStateChangeReturn
1994 gst_element_get_state_func (GstElement * element,
1995 GstState * state, GstState * pending, GstClockTime timeout)
1997 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1998 GstState old_pending;
2000 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2001 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2003 GST_OBJECT_LOCK (element);
2004 ret = GST_STATE_RETURN (element);
2005 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2006 gst_element_state_change_return_get_name (ret));
2008 /* we got an error, report immediately */
2009 if (ret == GST_STATE_CHANGE_FAILURE)
2012 /* we got no_preroll, report immediatly */
2013 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2016 /* no need to wait async if we are not async */
2017 if (ret != GST_STATE_CHANGE_ASYNC)
2020 old_pending = GST_STATE_PENDING (element);
2021 if (old_pending != GST_STATE_VOID_PENDING) {
2022 GTimeVal *timeval, abstimeout;
2025 if (timeout != GST_CLOCK_TIME_NONE) {
2026 glong add = timeout / 1000;
2031 /* make timeout absolute */
2032 g_get_current_time (&abstimeout);
2033 g_time_val_add (&abstimeout, add);
2034 timeval = &abstimeout;
2038 /* get cookie to detect state changes during waiting */
2039 cookie = element->state_cookie;
2041 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2042 "waiting for element to commit state");
2044 /* we have a pending state change, wait for it to complete */
2045 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2046 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2047 /* timeout triggered */
2048 ret = GST_STATE_CHANGE_ASYNC;
2050 if (cookie != element->state_cookie)
2053 /* could be success or failure */
2054 if (old_pending == GST_STATE (element)) {
2055 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2056 ret = GST_STATE_CHANGE_SUCCESS;
2058 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2059 ret = GST_STATE_CHANGE_FAILURE;
2062 /* if nothing is pending anymore we can return SUCCESS */
2063 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2064 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2065 ret = GST_STATE_CHANGE_SUCCESS;
2071 *state = GST_STATE (element);
2073 *pending = GST_STATE_PENDING (element);
2075 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2076 "state current: %s, pending: %s, result: %s",
2077 gst_element_state_get_name (GST_STATE (element)),
2078 gst_element_state_get_name (GST_STATE_PENDING (element)),
2079 gst_element_state_change_return_get_name (ret));
2080 GST_OBJECT_UNLOCK (element);
2087 *state = GST_STATE_VOID_PENDING;
2089 *pending = GST_STATE_VOID_PENDING;
2091 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2093 GST_OBJECT_UNLOCK (element);
2095 return GST_STATE_CHANGE_FAILURE;
2100 * gst_element_get_state:
2101 * @element: a #GstElement to get the state of.
2102 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2104 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2105 * state. Can be %NULL.
2106 * @timeout: a #GstClockTime to specify the timeout for an async
2107 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2109 * Gets the state of the element.
2111 * For elements that performed an ASYNC state change, as reported by
2112 * gst_element_set_state(), this function will block up to the
2113 * specified timeout value for the state change to complete.
2114 * If the element completes the state change or goes into
2115 * an error, this function returns immediately with a return value of
2116 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2118 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2119 * returns the current and pending state immediately.
2121 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2122 * successfully changed its state but is not able to provide data yet.
2123 * This mostly happens for live sources that only produce data in
2124 * %GST_STATE_PLAYING. While the state change return is equivalent to
2125 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2126 * some sink elements might not be able to complete their state change because
2127 * an element is not producing data to complete the preroll. When setting the
2128 * element to playing, the preroll will complete and playback will start.
2130 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2131 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2132 * element is still performing a state change or
2133 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2137 GstStateChangeReturn
2138 gst_element_get_state (GstElement * element,
2139 GstState * state, GstState * pending, GstClockTime timeout)
2141 GstElementClass *oclass;
2142 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2144 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2146 oclass = GST_ELEMENT_GET_CLASS (element);
2148 if (oclass->get_state)
2149 result = (oclass->get_state) (element, state, pending, timeout);
2155 * gst_element_abort_state:
2156 * @element: a #GstElement to abort the state of.
2158 * Abort the state change of the element. This function is used
2159 * by elements that do asynchronous state changes and find out
2160 * something is wrong.
2162 * This function should be called with the STATE_LOCK held.
2167 gst_element_abort_state (GstElement * element)
2171 #ifndef GST_DISABLE_GST_DEBUG
2175 g_return_if_fail (GST_IS_ELEMENT (element));
2177 GST_OBJECT_LOCK (element);
2178 pending = GST_STATE_PENDING (element);
2180 if (pending == GST_STATE_VOID_PENDING ||
2181 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2182 goto nothing_aborted;
2184 #ifndef GST_DISABLE_GST_DEBUG
2185 old_state = GST_STATE (element);
2187 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2188 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2189 gst_element_state_get_name (pending));
2193 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2195 GST_STATE_BROADCAST (element);
2196 GST_OBJECT_UNLOCK (element);
2202 GST_OBJECT_UNLOCK (element);
2207 /* Not static because GstBin has manual state handling too */
2209 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2210 GstState newstate, GstState pending)
2212 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2213 GstMessage *message;
2215 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2216 "notifying about state-changed %s to %s (%s pending)",
2217 gst_element_state_get_name (oldstate),
2218 gst_element_state_get_name (newstate),
2219 gst_element_state_get_name (pending));
2221 if (klass->state_changed)
2222 klass->state_changed (element, oldstate, newstate, pending);
2224 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2225 oldstate, newstate, pending);
2226 gst_element_post_message (element, message);
2230 * gst_element_continue_state:
2231 * @element: a #GstElement to continue the state change of.
2232 * @ret: The previous state return value
2234 * Commit the state change of the element and proceed to the next
2235 * pending state if any. This function is used
2236 * by elements that do asynchronous state changes.
2237 * The core will normally call this method automatically when an
2238 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2240 * If after calling this method the element still has not reached
2241 * the pending state, the next state change is performed.
2243 * This method is used internally and should normally not be called by plugins
2246 * Returns: The result of the commit state change.
2250 GstStateChangeReturn
2251 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2253 GstStateChangeReturn old_ret;
2254 GstState old_state, old_next;
2255 GstState current, next, pending;
2256 GstStateChange transition;
2258 GST_OBJECT_LOCK (element);
2259 old_ret = GST_STATE_RETURN (element);
2260 GST_STATE_RETURN (element) = ret;
2261 pending = GST_STATE_PENDING (element);
2263 /* check if there is something to commit */
2264 if (pending == GST_STATE_VOID_PENDING)
2265 goto nothing_pending;
2267 old_state = GST_STATE (element);
2268 /* this is the state we should go to next */
2269 old_next = GST_STATE_NEXT (element);
2270 /* update current state */
2271 current = GST_STATE (element) = old_next;
2273 /* see if we reached the final state */
2274 if (pending == current)
2277 next = GST_STATE_GET_NEXT (current, pending);
2278 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2280 GST_STATE_NEXT (element) = next;
2282 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2283 GST_OBJECT_UNLOCK (element);
2285 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2286 "committing state from %s to %s, pending %s, next %s",
2287 gst_element_state_get_name (old_state),
2288 gst_element_state_get_name (old_next),
2289 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2291 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2293 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2294 "continue state change %s to %s, final %s",
2295 gst_element_state_get_name (current),
2296 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2298 ret = gst_element_change_state (element, transition);
2304 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2305 GST_OBJECT_UNLOCK (element);
2310 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2311 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2313 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2314 "completed state change to %s", gst_element_state_get_name (pending));
2315 GST_OBJECT_UNLOCK (element);
2317 /* don't post silly messages with the same state. This can happen
2318 * when an element state is changed to what it already was. For bins
2319 * this can be the result of a lost state, which we check with the
2320 * previous return value.
2321 * We do signal the cond though as a _get_state() might be blocking
2323 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2324 _priv_gst_element_state_changed (element, old_state, old_next,
2325 GST_STATE_VOID_PENDING);
2327 GST_STATE_BROADCAST (element);
2334 * gst_element_lost_state:
2335 * @element: a #GstElement the state is lost of
2336 * @new_base_time: if a new base time should be distributed
2338 * Brings the element to the lost state. The current state of the
2339 * element is copied to the pending state so that any call to
2340 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2342 * An ASYNC_START message is posted with indication to distribute a new
2343 * base_time to the element when @new_base_time is %TRUE.
2344 * If the element was PLAYING, it will go to PAUSED. The element
2345 * will be restored to its PLAYING state by the parent pipeline when it
2348 * This is mostly used for elements that lost their preroll buffer
2349 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2350 * they will go to their pending state again when a new preroll buffer is
2351 * queued. This function can only be called when the element is currently
2352 * not in error or an async state change.
2354 * This function is used internally and should normally not be called from
2355 * plugins or applications.
2358 gst_element_lost_state (GstElement * element, gboolean new_base_time)
2360 GstState old_state, new_state;
2361 GstMessage *message;
2363 g_return_if_fail (GST_IS_ELEMENT (element));
2365 GST_OBJECT_LOCK (element);
2366 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2369 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2370 goto only_async_start;
2372 old_state = GST_STATE (element);
2374 /* when we were PLAYING, the new state is PAUSED. We will also not
2375 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2376 * when we preroll. */
2377 if (old_state > GST_STATE_PAUSED)
2378 new_state = GST_STATE_PAUSED;
2380 new_state = old_state;
2382 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2383 "lost state of %s to %s", gst_element_state_get_name (old_state),
2384 gst_element_state_get_name (new_state));
2386 GST_STATE (element) = new_state;
2387 GST_STATE_NEXT (element) = new_state;
2388 GST_STATE_PENDING (element) = new_state;
2389 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2391 GST_ELEMENT_START_TIME (element) = 0;
2392 GST_OBJECT_UNLOCK (element);
2394 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2397 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2398 gst_element_post_message (element, message);
2404 GST_OBJECT_UNLOCK (element);
2409 GST_OBJECT_UNLOCK (element);
2411 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2412 gst_element_post_message (element, message);
2418 * gst_element_set_state:
2419 * @element: a #GstElement to change state of.
2420 * @state: the element's new #GstState.
2422 * Sets the state of the element. This function will try to set the
2423 * requested state by going through all the intermediary states and calling
2424 * the class's state change function for each.
2426 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2427 * element will perform the remainder of the state change asynchronously in
2429 * An application can use gst_element_get_state() to wait for the completion
2430 * of the state change or it can wait for a state change message on the bus.
2432 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2433 * #GST_STATE_CHANGE_ASYNC.
2435 * Returns: Result of the state change using #GstStateChangeReturn.
2439 GstStateChangeReturn
2440 gst_element_set_state (GstElement * element, GstState state)
2442 GstElementClass *oclass;
2443 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2445 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2447 oclass = GST_ELEMENT_GET_CLASS (element);
2449 if (oclass->set_state)
2450 result = (oclass->set_state) (element, state);
2456 * default set state function, calculates the next state based
2457 * on current state and calls the change_state function
2459 static GstStateChangeReturn
2460 gst_element_set_state_func (GstElement * element, GstState state)
2462 GstState current, next, old_pending;
2463 GstStateChangeReturn ret;
2464 GstStateChange transition;
2465 GstStateChangeReturn old_ret;
2467 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2469 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2470 gst_element_state_get_name (state));
2472 /* state lock is taken to protect the set_state() and get_state()
2473 * procedures, it does not lock any variables. */
2474 GST_STATE_LOCK (element);
2476 /* now calculate how to get to the new state */
2477 GST_OBJECT_LOCK (element);
2478 old_ret = GST_STATE_RETURN (element);
2479 /* previous state change returned an error, remove all pending
2480 * and next states */
2481 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2482 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2483 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2484 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2487 current = GST_STATE (element);
2488 next = GST_STATE_NEXT (element);
2489 old_pending = GST_STATE_PENDING (element);
2491 /* this is the (new) state we should go to. TARGET is the last state we set on
2493 if (state != GST_STATE_TARGET (element)) {
2494 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2495 "setting target state to %s", gst_element_state_get_name (state));
2496 GST_STATE_TARGET (element) = state;
2497 /* increment state cookie so that we can track each state change. We only do
2498 * this if this is actually a new state change. */
2499 element->state_cookie++;
2501 GST_STATE_PENDING (element) = state;
2503 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2504 "current %s, old_pending %s, next %s, old return %s",
2505 gst_element_state_get_name (current),
2506 gst_element_state_get_name (old_pending),
2507 gst_element_state_get_name (next),
2508 gst_element_state_change_return_get_name (old_ret));
2510 /* if the element was busy doing a state change, we just update the
2511 * target state, it'll get to it async then. */
2512 if (old_pending != GST_STATE_VOID_PENDING) {
2513 /* upwards state change will happen ASYNC */
2514 if (old_pending <= state)
2516 /* element is going to this state already */
2517 else if (next == state)
2519 /* element was performing an ASYNC upward state change and
2520 * we request to go downward again. Start from the next pending
2522 else if (next > state
2523 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2527 next = GST_STATE_GET_NEXT (current, state);
2528 /* now we store the next state */
2529 GST_STATE_NEXT (element) = next;
2530 /* mark busy, we need to check that there is actually a state change
2531 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2532 * the default element change_state function has no way to know what the
2533 * old value was... could consider this a FIXME...*/
2534 if (current != next)
2535 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2537 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2539 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2540 "%s: setting state from %s to %s",
2541 (next != state ? "intermediate" : "final"),
2542 gst_element_state_get_name (current), gst_element_state_get_name (next));
2544 /* now signal any waiters, they will error since the cookie was incremented */
2545 GST_STATE_BROADCAST (element);
2547 GST_OBJECT_UNLOCK (element);
2549 ret = gst_element_change_state (element, transition);
2551 GST_STATE_UNLOCK (element);
2553 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2554 gst_element_state_change_return_get_name (ret));
2560 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2561 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2562 "element was busy with async state change");
2563 GST_OBJECT_UNLOCK (element);
2565 GST_STATE_UNLOCK (element);
2567 return GST_STATE_CHANGE_ASYNC;
2572 * gst_element_change_state:
2573 * @element: a #GstElement
2574 * @transition: the requested transition
2576 * Perform @transition on @element.
2578 * This function must be called with STATE_LOCK held and is mainly used
2581 * Returns: the #GstStateChangeReturn of the state transition.
2583 GstStateChangeReturn
2584 gst_element_change_state (GstElement * element, GstStateChange transition)
2586 GstElementClass *oclass;
2587 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2589 oclass = GST_ELEMENT_GET_CLASS (element);
2591 /* call the state change function so it can set the state */
2592 if (oclass->change_state)
2593 ret = (oclass->change_state) (element, transition);
2595 ret = GST_STATE_CHANGE_FAILURE;
2598 case GST_STATE_CHANGE_FAILURE:
2599 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2600 "have FAILURE change_state return");
2601 /* state change failure */
2602 gst_element_abort_state (element);
2604 case GST_STATE_CHANGE_ASYNC:
2608 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2609 "element will change state ASYNC");
2611 target = GST_STATE_TARGET (element);
2613 if (target > GST_STATE_READY)
2616 /* else we just continue the state change downwards */
2617 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2618 "forcing commit state %s <= %s",
2619 gst_element_state_get_name (target),
2620 gst_element_state_get_name (GST_STATE_READY));
2622 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2625 case GST_STATE_CHANGE_SUCCESS:
2626 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2627 "element changed state SUCCESS");
2628 /* we can commit the state now which will proceeed to
2630 ret = gst_element_continue_state (element, ret);
2632 case GST_STATE_CHANGE_NO_PREROLL:
2633 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2634 "element changed state NO_PREROLL");
2635 /* we can commit the state now which will proceeed to
2637 ret = gst_element_continue_state (element, ret);
2640 goto invalid_return;
2643 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2648 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2656 GST_OBJECT_LOCK (element);
2657 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2658 g_critical ("%s: unknown return value %d from a state change function",
2659 GST_ELEMENT_NAME (element), ret);
2661 /* we are in error now */
2662 ret = GST_STATE_CHANGE_FAILURE;
2663 GST_STATE_RETURN (element) = ret;
2664 GST_OBJECT_UNLOCK (element);
2670 /* gst_iterator_fold functions for pads_activate
2671 * Stop the iterator if activating one pad failed. */
2673 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2675 GstPad *pad = g_value_get_object (vpad);
2676 gboolean cont = TRUE;
2678 if (!(cont = gst_pad_set_active (pad, *active)))
2679 g_value_set_boolean (ret, FALSE);
2684 /* returns false on error or early cutout of the fold, true if all
2685 * pads in @iter were (de)activated successfully. */
2687 iterator_activate_fold_with_resync (GstIterator * iter,
2688 GstIteratorFoldFunction func, gpointer user_data)
2690 GstIteratorResult ires;
2693 /* no need to unset this later, it's just a boolean */
2694 g_value_init (&ret, G_TYPE_BOOLEAN);
2695 g_value_set_boolean (&ret, TRUE);
2698 ires = gst_iterator_fold (iter, func, &ret, user_data);
2700 case GST_ITERATOR_RESYNC:
2701 /* need to reset the result again */
2702 g_value_set_boolean (&ret, TRUE);
2703 gst_iterator_resync (iter);
2705 case GST_ITERATOR_DONE:
2706 /* all pads iterated, return collected value */
2709 /* iterator returned _ERROR or premature end with _OK,
2710 * mark an error and exit */
2711 g_value_set_boolean (&ret, FALSE);
2716 /* return collected value */
2717 return g_value_get_boolean (&ret);
2720 /* is called with STATE_LOCK
2722 * Pads are activated from source pads to sinkpads.
2725 gst_element_pads_activate (GstElement * element, gboolean active)
2730 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2731 "pads_activate with active %d", active);
2733 iter = gst_element_iterate_src_pads (element);
2735 iterator_activate_fold_with_resync (iter,
2736 (GstIteratorFoldFunction) activate_pads, &active);
2737 gst_iterator_free (iter);
2738 if (G_UNLIKELY (!res))
2741 iter = gst_element_iterate_sink_pads (element);
2743 iterator_activate_fold_with_resync (iter,
2744 (GstIteratorFoldFunction) activate_pads, &active);
2745 gst_iterator_free (iter);
2746 if (G_UNLIKELY (!res))
2749 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2750 "pads_activate successful");
2757 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2758 "source pads_activate failed");
2763 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2764 "sink pads_activate failed");
2769 /* is called with STATE_LOCK */
2770 static GstStateChangeReturn
2771 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2773 GstState state, next;
2774 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2776 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2778 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2779 next = GST_STATE_TRANSITION_NEXT (transition);
2781 /* if the element already is in the given state, we just return success */
2782 if (next == GST_STATE_VOID_PENDING || state == next)
2785 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2786 "default handler tries setting state from %s to %s (%04x)",
2787 gst_element_state_get_name (state),
2788 gst_element_state_get_name (next), transition);
2790 switch (transition) {
2791 case GST_STATE_CHANGE_NULL_TO_READY:
2793 case GST_STATE_CHANGE_READY_TO_PAUSED:
2794 if (!gst_element_pads_activate (element, TRUE)) {
2795 result = GST_STATE_CHANGE_FAILURE;
2798 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2800 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2802 case GST_STATE_CHANGE_PAUSED_TO_READY:
2803 case GST_STATE_CHANGE_READY_TO_NULL:
2804 /* deactivate pads in both cases, since they are activated on
2805 ready->paused but the element might not have made it to paused */
2806 if (!gst_element_pads_activate (element, FALSE)) {
2807 result = GST_STATE_CHANGE_FAILURE;
2811 /* this will catch real but unhandled state changes;
2812 * can only be caused by:
2813 * - a new state was added
2814 * - somehow the element was asked to jump across an intermediate state
2816 g_warning ("Unhandled state change from %s to %s",
2817 gst_element_state_get_name (state),
2818 gst_element_state_get_name (next));
2825 GST_OBJECT_LOCK (element);
2826 result = GST_STATE_RETURN (element);
2827 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2828 "element is already in the %s state",
2829 gst_element_state_get_name (state));
2830 GST_OBJECT_UNLOCK (element);
2837 * gst_element_get_factory:
2838 * @element: a #GstElement to request the element factory of.
2840 * Retrieves the factory that was used to create this element.
2842 * Returns: (transfer none): the #GstElementFactory used for creating this
2843 * element. no refcounting is needed.
2846 gst_element_get_factory (GstElement * element)
2848 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2850 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2854 gst_element_dispose (GObject * object)
2856 GstElement *element = GST_ELEMENT_CAST (object);
2860 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2862 if (GST_STATE (element) != GST_STATE_NULL)
2865 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2866 "removing %d pads", g_list_length (element->pads));
2867 /* first we break all our links with the outside */
2868 while (element->pads && element->pads->data) {
2869 /* don't call _remove_pad with NULL */
2870 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2872 if (G_UNLIKELY (element->pads != NULL)) {
2873 g_critical ("could not remove pads from element %s",
2874 GST_STR_NULL (GST_OBJECT_NAME (object)));
2877 GST_OBJECT_LOCK (element);
2878 clock_p = &element->clock;
2879 bus_p = &element->bus;
2880 gst_object_replace ((GstObject **) clock_p, NULL);
2881 gst_object_replace ((GstObject **) bus_p, NULL);
2882 GST_OBJECT_UNLOCK (element);
2884 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2886 G_OBJECT_CLASS (parent_class)->dispose (object);
2895 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2897 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2899 "You need to explicitly set elements to the NULL state before\n"
2900 "dropping the final reference, to allow them to clean up.\n"
2901 "This problem may also be caused by a refcounting bug in the\n"
2902 "application or some element.\n",
2903 GST_OBJECT_NAME (element),
2904 gst_element_state_get_name (GST_STATE (element)),
2905 is_locked ? " (locked)" : "");
2911 gst_element_finalize (GObject * object)
2913 GstElement *element = GST_ELEMENT_CAST (object);
2915 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2917 g_cond_free (element->state_cond);
2918 g_static_rec_mutex_free (&element->state_lock);
2920 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2922 G_OBJECT_CLASS (parent_class)->finalize (object);
2926 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2930 g_return_if_fail (GST_IS_ELEMENT (element));
2932 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2934 GST_OBJECT_LOCK (element);
2935 bus_p = &GST_ELEMENT_BUS (element);
2936 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2937 GST_OBJECT_UNLOCK (element);
2941 * gst_element_set_bus:
2942 * @element: a #GstElement to set the bus of.
2943 * @bus: (transfer none): the #GstBus to set.
2945 * Sets the bus of the element. Increases the refcount on the bus.
2946 * For internal use only, unless you're testing elements.
2951 gst_element_set_bus (GstElement * element, GstBus * bus)
2953 GstElementClass *oclass;
2955 g_return_if_fail (GST_IS_ELEMENT (element));
2957 oclass = GST_ELEMENT_GET_CLASS (element);
2959 if (oclass->set_bus)
2960 oclass->set_bus (element, bus);
2964 * gst_element_get_bus:
2965 * @element: a #GstElement to get the bus of.
2967 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2968 * bus for the application.
2970 * Returns: (transfer full): the element's #GstBus. unref after usage.
2975 gst_element_get_bus (GstElement * element)
2977 GstBus *result = NULL;
2979 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2981 GST_OBJECT_LOCK (element);
2982 if ((result = GST_ELEMENT_BUS (element)))
2983 gst_object_ref (result);
2984 GST_OBJECT_UNLOCK (element);
2986 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,