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 "gstelementdetails.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 #ifndef GST_DISABLE_LOADSAVE
138 static xmlNodePtr gst_element_save_thyself (GstObject * object,
140 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
143 static GstObjectClass *parent_class = NULL;
144 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
146 /* this is used in gstelementfactory.c:gst_element_register() */
147 GQuark _gst_elementclass_factory = 0;
150 gst_element_get_type (void)
152 static volatile gsize gst_element_type = 0;
154 if (g_once_init_enter (&gst_element_type)) {
156 static const GTypeInfo element_info = {
157 sizeof (GstElementClass),
158 gst_element_base_class_init,
159 gst_element_base_class_finalize,
160 (GClassInitFunc) gst_element_class_init,
165 (GInstanceInitFunc) gst_element_init,
169 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
170 &element_info, G_TYPE_FLAG_ABSTRACT);
172 _gst_elementclass_factory =
173 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
174 g_once_init_leave (&gst_element_type, _type);
176 return gst_element_type;
180 gst_element_class_init (GstElementClass * klass)
182 GObjectClass *gobject_class;
183 GstObjectClass *gstobject_class;
185 gobject_class = (GObjectClass *) klass;
186 gstobject_class = (GstObjectClass *) klass;
188 parent_class = g_type_class_peek_parent (klass);
191 * GstElement::pad-added:
192 * @gstelement: the object which received the signal
193 * @new_pad: the pad that has been added
195 * a new #GstPad has been added to the element.
197 gst_element_signals[PAD_ADDED] =
198 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
199 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
200 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
202 * GstElement::pad-removed:
203 * @gstelement: the object which received the signal
204 * @old_pad: the pad that has been removed
206 * a #GstPad has been removed from the element
208 gst_element_signals[PAD_REMOVED] =
209 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
210 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
211 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
213 * GstElement::no-more-pads:
214 * @gstelement: the object which received the signal
216 * This signals that the element will not generate more dynamic pads.
218 gst_element_signals[NO_MORE_PADS] =
219 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
220 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
221 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
223 gobject_class->dispose = gst_element_dispose;
224 gobject_class->finalize = gst_element_finalize;
226 #ifndef GST_DISABLE_LOADSAVE
227 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
228 gstobject_class->restore_thyself =
229 GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
232 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
233 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
234 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
235 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
236 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
237 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
238 klass->numpadtemplates = 0;
240 klass->elementfactory = NULL;
244 gst_element_base_class_init (gpointer g_class)
246 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
248 /* FIXME 0.11: Copy the element details and instead of clearing the
249 * pad template list copy the list and increase the refcount of
250 * the pad templates by one.
252 * This will make it possible to add pad templates and set element
253 * details in the class_init functions and is the real GObject way
255 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
257 memset (&element_class->details, 0, sizeof (GstElementDetails));
258 element_class->padtemplates = NULL;
260 /* set the factory, see gst_element_register() */
261 element_class->elementfactory =
262 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
263 _gst_elementclass_factory);
264 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
265 element_class->elementfactory);
269 gst_element_base_class_finalize (gpointer g_class)
271 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
273 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
274 g_list_free (klass->padtemplates);
275 __gst_element_details_clear (&klass->details);
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 element->state_lock = g_new0 (GStaticRecMutex, 1);
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: 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: 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: 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: 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: 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'",
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: 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 /* FIXME, locking order? */
865 GST_OBJECT_LOCK (element);
866 g_critical ("Padname %s:%s does not belong to element %s when removing",
867 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
868 GST_OBJECT_UNLOCK (element);
869 GST_OBJECT_UNLOCK (pad);
875 * gst_element_no_more_pads:
876 * @element: a #GstElement
878 * Use this function to signal that the element does not expect any more pads
879 * to show up in the current pipeline. This function should be called whenever
880 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
881 * pad templates use this in combination with autopluggers to figure out that
882 * the element is done initializing its pads.
884 * This function emits the #GstElement::no-more-pads signal.
889 gst_element_no_more_pads (GstElement * element)
891 g_return_if_fail (GST_IS_ELEMENT (element));
893 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
897 pad_compare_name (GstPad * pad1, const gchar * name)
901 GST_OBJECT_LOCK (pad1);
902 result = strcmp (GST_PAD_NAME (pad1), name);
903 GST_OBJECT_UNLOCK (pad1);
909 * gst_element_get_static_pad:
910 * @element: a #GstElement to find a static pad of.
911 * @name: the name of the static #GstPad to retrieve.
913 * Retrieves a pad from @element by name. This version only retrieves
914 * already-existing (i.e. 'static') pads.
916 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
922 gst_element_get_static_pad (GstElement * element, const gchar * name)
925 GstPad *result = NULL;
927 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
928 g_return_val_if_fail (name != NULL, NULL);
930 GST_OBJECT_LOCK (element);
932 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
934 result = GST_PAD_CAST (find->data);
935 gst_object_ref (result);
938 if (result == NULL) {
939 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
940 name, GST_ELEMENT_NAME (element));
942 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
943 GST_ELEMENT_NAME (element), name);
945 GST_OBJECT_UNLOCK (element);
951 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
954 GstPad *newpad = NULL;
955 GstElementClass *oclass;
957 oclass = GST_ELEMENT_GET_CLASS (element);
959 if (oclass->request_new_pad)
960 newpad = (oclass->request_new_pad) (element, templ, name);
963 gst_object_ref (newpad);
969 * gst_element_get_request_pad:
970 * @element: a #GstElement to find a request pad of.
971 * @name: the name of the request #GstPad to retrieve.
973 * Retrieves a pad from the element by name. This version only retrieves
974 * request pads. The pad should be released with
975 * gst_element_release_request_pad().
977 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
980 gst_element_get_request_pad (GstElement * element, const gchar * name)
982 GstPadTemplate *templ = NULL;
984 const gchar *req_name = NULL;
985 gboolean templ_found = FALSE;
989 gchar *str, *endptr = NULL;
990 GstElementClass *class;
992 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
993 g_return_val_if_fail (name != NULL, NULL);
995 class = GST_ELEMENT_GET_CLASS (element);
997 /* if the name contains a %, we assume it's the complete template name. Get
998 * the template and try to get a pad */
999 if (strstr (name, "%")) {
1000 templ = gst_element_class_get_request_pad_template (class, name);
1005 /* there is no % in the name, try to find a matching template */
1006 list = class->padtemplates;
1007 while (!templ_found && list) {
1008 templ = (GstPadTemplate *) list->data;
1009 if (templ->presence == GST_PAD_REQUEST) {
1010 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1011 templ->name_template);
1012 /* see if we find an exact match */
1013 if (strcmp (name, templ->name_template) == 0) {
1018 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1019 and %d, occurring at the end of the name_template, are the only
1021 else if ((str = strchr (templ->name_template, '%'))
1022 && strncmp (templ->name_template, name,
1023 str - templ->name_template) == 0
1024 && strlen (name) > str - templ->name_template) {
1025 data = name + (str - templ->name_template);
1026 if (*(str + 1) == 'd') {
1028 n = (gint) strtol (data, &endptr, 10);
1029 if (endptr && *endptr == '\0') {
1049 pad = gst_element_request_pad (element, templ, req_name);
1055 * gst_element_get_pad:
1056 * @element: a #GstElement.
1057 * @name: the name of the pad to retrieve.
1059 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1060 * first, then gst_element_get_request_pad().
1062 * Deprecated: This function is deprecated as it's unclear if the reference
1063 * to the result pad should be released with gst_object_unref() in case of a static pad
1064 * or gst_element_release_request_pad() in case of a request pad.
1065 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1067 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1068 * depending on the type of the pad.
1070 #ifndef GST_REMOVE_DEPRECATED
1071 #ifdef GST_DISABLE_DEPRECATED
1072 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1075 gst_element_get_pad (GstElement * element, const gchar * name)
1079 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1080 g_return_val_if_fail (name != NULL, NULL);
1082 pad = gst_element_get_static_pad (element, name);
1084 pad = gst_element_get_request_pad (element, name);
1088 #endif /* GST_REMOVE_DEPRECATED */
1090 static GstIteratorItem
1091 iterate_pad (GstIterator * it, GstPad * pad)
1093 gst_object_ref (pad);
1094 return GST_ITERATOR_ITEM_PASS;
1097 static GstIterator *
1098 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1100 GstIterator *result;
1102 GST_OBJECT_LOCK (element);
1103 gst_object_ref (element);
1104 result = gst_iterator_new_list (GST_TYPE_PAD,
1105 GST_OBJECT_GET_LOCK (element),
1106 &element->pads_cookie,
1109 (GstIteratorItemFunction) iterate_pad,
1110 (GstIteratorDisposeFunction) gst_object_unref);
1111 GST_OBJECT_UNLOCK (element);
1117 * gst_element_iterate_pads:
1118 * @element: a #GstElement to iterate pads of.
1120 * Retrieves an iterattor of @element's pads. The iterator should
1121 * be freed after usage.
1123 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1128 gst_element_iterate_pads (GstElement * element)
1130 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1132 return gst_element_iterate_pad_list (element, &element->pads);
1136 * gst_element_iterate_src_pads:
1137 * @element: a #GstElement.
1139 * Retrieves an iterator of @element's source pads.
1141 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1146 gst_element_iterate_src_pads (GstElement * element)
1148 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1150 return gst_element_iterate_pad_list (element, &element->srcpads);
1154 * gst_element_iterate_sink_pads:
1155 * @element: a #GstElement.
1157 * Retrieves an iterator of @element's sink pads.
1159 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1164 gst_element_iterate_sink_pads (GstElement * element)
1166 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1168 return gst_element_iterate_pad_list (element, &element->sinkpads);
1172 * gst_element_class_add_pad_template:
1173 * @klass: the #GstElementClass to add the pad template to.
1174 * @templ: a #GstPadTemplate to add to the element class.
1176 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1177 * functions of classes.
1180 gst_element_class_add_pad_template (GstElementClass * klass,
1181 GstPadTemplate * templ)
1183 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1184 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1186 /* FIXME 0.11: allow replacing the pad templates by
1187 * calling this with the same name as an already existing pad
1188 * template. For this we _must_ _not_ ref the added pad template
1189 * a second time and _must_ document that this function takes
1190 * ownership of the pad template. Otherwise we will leak pad templates
1191 * or the caller unref's the pad template and it disappears */
1192 /* avoid registering pad templates with the same name */
1193 g_return_if_fail (gst_element_class_get_pad_template (klass,
1194 templ->name_template) == NULL);
1196 klass->padtemplates = g_list_append (klass->padtemplates,
1197 gst_object_ref (templ));
1198 klass->numpadtemplates++;
1202 * gst_element_class_set_details:
1203 * @klass: class to set details for
1204 * @details: details to set
1206 * Sets the detailed information for a #GstElementClass.
1207 * <note>This function is for use in _base_init functions only.</note>
1209 * The @details are copied.
1212 gst_element_class_set_details (GstElementClass * klass,
1213 const GstElementDetails * details)
1215 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1216 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1218 __gst_element_details_copy (&klass->details, details);
1222 * gst_element_class_set_details_simple:
1223 * @klass: class to set details for
1224 * @longname: The long English name of the element. E.g. "File Sink"
1225 * @classification: String describing the type of element, as an unordered list
1226 * separated with slashes ('/'). See draft-klass.txt of the design docs
1227 * for more details and common types. E.g: "Sink/File"
1228 * @description: Sentence describing the purpose of the element.
1229 * E.g: "Write stream to a file"
1230 * @author: Name and contact details of the author(s). Use \n to separate
1231 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1233 * Sets the detailed information for a #GstElementClass. Simpler version of
1234 * gst_element_class_set_details() that generates less linker overhead.
1235 * <note>This function is for use in _base_init functions only.</note>
1237 * The detail parameter strings are copied into the #GstElementDetails for
1238 * the element class.
1243 gst_element_class_set_details_simple (GstElementClass * klass,
1244 const gchar * longname, const gchar * classification,
1245 const gchar * description, const gchar * author)
1247 const GstElementDetails details =
1248 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1249 (gchar *) description, (gchar *) author);
1251 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1253 __gst_element_details_copy (&klass->details, &details);
1257 * gst_element_class_get_pad_template_list:
1258 * @element_class: a #GstElementClass to get pad templates of.
1260 * Retrieves a list of the pad templates associated with @element_class. The
1261 * list must not be modified by the calling code.
1262 * <note>If you use this function in the #GInstanceInitFunc of an object class
1263 * that has subclasses, make sure to pass the g_class parameter of the
1264 * #GInstanceInitFunc here.</note>
1266 * Returns: the #GList of padtemplates.
1269 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1271 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1273 return element_class->padtemplates;
1277 * gst_element_class_get_pad_template:
1278 * @element_class: a #GstElementClass to get the pad template of.
1279 * @name: the name of the #GstPadTemplate to get.
1281 * Retrieves a padtemplate from @element_class with the given name.
1282 * <note>If you use this function in the #GInstanceInitFunc of an object class
1283 * that has subclasses, make sure to pass the g_class parameter of the
1284 * #GInstanceInitFunc here.</note>
1286 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1287 * No unreferencing is necessary.
1290 gst_element_class_get_pad_template (GstElementClass * element_class,
1295 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1296 g_return_val_if_fail (name != NULL, NULL);
1298 padlist = element_class->padtemplates;
1301 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1303 if (strcmp (padtempl->name_template, name) == 0)
1306 padlist = g_list_next (padlist);
1312 static GstPadTemplate *
1313 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1316 GstPadTemplate *tmpl;
1318 tmpl = gst_element_class_get_pad_template (element_class, name);
1319 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1325 /* get a random pad on element of the given direction.
1326 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1329 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1330 GstPadDirection dir)
1332 GstPad *result = NULL;
1335 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1339 GST_OBJECT_LOCK (element);
1340 pads = element->srcpads;
1343 GST_OBJECT_LOCK (element);
1344 pads = element->sinkpads;
1347 goto wrong_direction;
1349 for (; pads; pads = g_list_next (pads)) {
1350 GstPad *pad = GST_PAD_CAST (pads->data);
1352 GST_OBJECT_LOCK (pad);
1353 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1354 GST_DEBUG_PAD_NAME (pad));
1356 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1357 /* if we require a linked pad, and it is not linked, continue the
1359 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1360 GST_DEBUG_PAD_NAME (pad));
1361 GST_OBJECT_UNLOCK (pad);
1364 /* found a pad, stop search */
1365 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1366 GST_DEBUG_PAD_NAME (pad));
1367 GST_OBJECT_UNLOCK (pad);
1373 gst_object_ref (result);
1375 GST_OBJECT_UNLOCK (element);
1379 /* ERROR handling */
1382 g_warning ("unknown pad direction %d", dir);
1388 gst_element_default_send_event (GstElement * element, GstEvent * event)
1390 gboolean result = FALSE;
1393 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1394 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1395 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1398 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1399 "pushing %s event to random %s pad %s:%s",
1400 GST_EVENT_TYPE_NAME (event),
1401 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1402 GST_DEBUG_PAD_NAME (pad));
1404 result = gst_pad_push_event (pad, event);
1405 gst_object_unref (pad);
1407 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1408 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1414 * gst_element_send_event:
1415 * @element: a #GstElement to send the event to.
1416 * @event: the #GstEvent to send to the element.
1418 * Sends an event to an element. If the element doesn't implement an
1419 * event handler, the event will be pushed on a random linked sink pad for
1420 * upstream events or a random linked source pad for downstream events.
1422 * This function takes owership of the provided event so you should
1423 * gst_event_ref() it if you want to reuse the event after this call.
1425 * Returns: %TRUE if the event was handled.
1430 gst_element_send_event (GstElement * element, GstEvent * event)
1432 GstElementClass *oclass;
1433 gboolean result = FALSE;
1435 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1436 g_return_val_if_fail (event != NULL, FALSE);
1438 oclass = GST_ELEMENT_GET_CLASS (element);
1440 GST_STATE_LOCK (element);
1441 if (oclass->send_event) {
1442 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1443 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1444 result = oclass->send_event (element, event);
1446 result = gst_element_default_send_event (element, event);
1448 GST_STATE_UNLOCK (element);
1455 * @element: a #GstElement to send the event to.
1456 * @rate: The new playback rate
1457 * @format: The format of the seek values
1458 * @flags: The optional seek flags.
1459 * @cur_type: The type and flags for the new current position
1460 * @cur: The value of the new current position
1461 * @stop_type: The type and flags for the new stop position
1462 * @stop: The value of the new stop position
1464 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1465 * the parameters. The seek event is sent to the element using
1466 * gst_element_send_event().
1468 * Returns: %TRUE if the event was handled.
1473 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1474 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1475 GstSeekType stop_type, gint64 stop)
1480 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1483 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1484 result = gst_element_send_event (element, event);
1490 * gst_element_get_query_types:
1491 * @element: a #GstElement to query
1493 * Get an array of query types from the element.
1494 * If the element doesn't implement a query types function,
1495 * the query will be forwarded to the peer of a random linked sink pad.
1497 * Returns: An array of #GstQueryType elements that should not
1498 * be freed or modified.
1502 const GstQueryType *
1503 gst_element_get_query_types (GstElement * element)
1505 GstElementClass *oclass;
1506 const GstQueryType *result = NULL;
1508 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1510 oclass = GST_ELEMENT_GET_CLASS (element);
1512 if (oclass->get_query_types) {
1513 result = oclass->get_query_types (element);
1515 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1518 GstPad *peer = gst_pad_get_peer (pad);
1521 result = gst_pad_get_query_types (peer);
1523 gst_object_unref (peer);
1525 gst_object_unref (pad);
1532 gst_element_default_query (GstElement * element, GstQuery * query)
1534 gboolean result = FALSE;
1537 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1539 result = gst_pad_query (pad, query);
1541 gst_object_unref (pad);
1543 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1545 GstPad *peer = gst_pad_get_peer (pad);
1548 result = gst_pad_query (peer, query);
1550 gst_object_unref (peer);
1552 gst_object_unref (pad);
1559 * gst_element_query:
1560 * @element: a #GstElement to perform the query on.
1561 * @query: the #GstQuery.
1563 * Performs a query on the given element.
1565 * For elements that don't implement a query handler, this function
1566 * forwards the query to a random srcpad or to the peer of a
1567 * random linked sinkpad of this element.
1569 * Returns: TRUE if the query could be performed.
1574 gst_element_query (GstElement * element, GstQuery * query)
1576 GstElementClass *oclass;
1577 gboolean result = FALSE;
1579 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1580 g_return_val_if_fail (query != NULL, FALSE);
1582 oclass = GST_ELEMENT_GET_CLASS (element);
1584 if (oclass->query) {
1585 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1586 GST_ELEMENT_NAME (element));
1587 result = oclass->query (element, query);
1589 result = gst_element_default_query (element, query);
1595 * gst_element_post_message:
1596 * @element: a #GstElement posting the message
1597 * @message: a #GstMessage to post
1599 * Post a message on the element's #GstBus. This function takes ownership of the
1600 * message; if you want to access the message after this call, you should add an
1601 * additional reference before calling.
1603 * Returns: %TRUE if the message was successfully posted. The function returns
1604 * %FALSE if the element did not have a bus.
1609 gst_element_post_message (GstElement * element, GstMessage * message)
1612 gboolean result = FALSE;
1614 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1615 g_return_val_if_fail (message != NULL, FALSE);
1617 GST_OBJECT_LOCK (element);
1620 if (G_UNLIKELY (bus == NULL))
1623 gst_object_ref (bus);
1624 GST_OBJECT_UNLOCK (element);
1626 /* we release the element lock when posting the message so that any
1627 * (synchronous) message handlers can operate on the element */
1628 result = gst_bus_post (bus, message);
1629 gst_object_unref (bus);
1636 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1637 "not posting message %p: no bus", message);
1638 GST_OBJECT_UNLOCK (element);
1639 gst_message_unref (message);
1645 * _gst_element_error_printf:
1646 * @format: the printf-like format to use, or %NULL
1648 * This function is only used internally by the gst_element_error() macro.
1650 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1655 _gst_element_error_printf (const gchar * format, ...)
1665 va_start (args, format);
1666 buffer = g_strdup_vprintf (format, args);
1672 * gst_element_message_full:
1673 * @element: a #GstElement to send message from
1674 * @type: the #GstMessageType
1675 * @domain: the GStreamer GError domain this message belongs to
1676 * @code: the GError code belonging to the domain
1677 * @text: an allocated text string to be used as a replacement for the
1678 * default message connected to code, or %NULL
1679 * @debug: an allocated debug message to be used as a replacement for the
1680 * default debugging information, or %NULL
1681 * @file: the source code file where the error was generated
1682 * @function: the source code function where the error was generated
1683 * @line: the source code line where the error was generated
1685 * Post an error, warning or info message on the bus from inside an element.
1687 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1688 * #GST_MESSAGE_INFO.
1692 void gst_element_message_full
1693 (GstElement * element, GstMessageType type,
1694 GQuark domain, gint code, gchar * text,
1695 gchar * debug, const gchar * file, const gchar * function, gint line)
1697 GError *gerror = NULL;
1701 gboolean has_debug = TRUE;
1702 GstMessage *message = NULL;
1705 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1706 g_return_if_fail (GST_IS_ELEMENT (element));
1707 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1708 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1710 /* check if we send the given text or the default error text */
1711 if ((text == NULL) || (text[0] == 0)) {
1712 /* text could have come from g_strdup_printf (""); */
1714 sent_text = gst_error_get_message (domain, code);
1718 /* construct a sent_debug with extra information from source */
1719 if ((debug == NULL) || (debug[0] == 0)) {
1720 /* debug could have come from g_strdup_printf (""); */
1724 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1726 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1727 file, line, function, name, debug);
1729 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1730 file, line, function, name);
1734 /* create gerror and post message */
1735 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1737 gerror = g_error_new_literal (domain, code, sent_text);
1740 case GST_MESSAGE_ERROR:
1742 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1744 case GST_MESSAGE_WARNING:
1745 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1748 case GST_MESSAGE_INFO:
1749 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1753 g_assert_not_reached ();
1756 gst_element_post_message (element, message);
1758 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1759 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1762 g_error_free (gerror);
1763 g_free (sent_debug);
1768 * gst_element_is_locked_state:
1769 * @element: a #GstElement.
1771 * Checks if the state of an element is locked.
1772 * If the state of an element is locked, state changes of the parent don't
1773 * affect the element.
1774 * This way you can leave currently unused elements inside bins. Just lock their
1775 * state before changing the state from #GST_STATE_NULL.
1779 * Returns: TRUE, if the element's state is locked.
1782 gst_element_is_locked_state (GstElement * element)
1786 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1788 GST_OBJECT_LOCK (element);
1789 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1790 GST_OBJECT_UNLOCK (element);
1796 * gst_element_set_locked_state:
1797 * @element: a #GstElement
1798 * @locked_state: TRUE to lock the element's state
1800 * Locks the state of an element, so state changes of the parent don't affect
1801 * this element anymore.
1805 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1806 * or the elements state-locking needed no change.
1809 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1813 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1815 GST_OBJECT_LOCK (element);
1816 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1818 if (G_UNLIKELY (old == locked_state))
1822 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1823 GST_ELEMENT_NAME (element));
1824 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1826 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1827 GST_ELEMENT_NAME (element));
1828 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1830 GST_OBJECT_UNLOCK (element);
1836 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1837 GST_ELEMENT_NAME (element), old);
1838 GST_OBJECT_UNLOCK (element);
1845 * gst_element_sync_state_with_parent:
1846 * @element: a #GstElement.
1848 * Tries to change the state of the element to the same as its parent.
1849 * If this function returns FALSE, the state of element is undefined.
1851 * Returns: TRUE, if the element's state could be synced to the parent's state.
1856 gst_element_sync_state_with_parent (GstElement * element)
1860 GstStateChangeReturn ret;
1862 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1864 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1865 GstState parent_current, parent_pending;
1867 GST_OBJECT_LOCK (parent);
1868 parent_current = GST_STATE (parent);
1869 parent_pending = GST_STATE_PENDING (parent);
1870 GST_OBJECT_UNLOCK (parent);
1872 /* set to pending if there is one, else we set it to the current state of
1874 if (parent_pending != GST_STATE_VOID_PENDING)
1875 target = parent_pending;
1877 target = parent_current;
1879 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1880 "syncing state (%s) to parent %s %s (%s, %s)",
1881 gst_element_state_get_name (GST_STATE (element)),
1882 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1883 gst_element_state_get_name (parent_current),
1884 gst_element_state_get_name (parent_pending));
1886 ret = gst_element_set_state (element, target);
1887 if (ret == GST_STATE_CHANGE_FAILURE)
1890 gst_object_unref (parent);
1894 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1901 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1902 "syncing state failed (%s)",
1903 gst_element_state_change_return_get_name (ret));
1904 gst_object_unref (parent);
1910 static GstStateChangeReturn
1911 gst_element_get_state_func (GstElement * element,
1912 GstState * state, GstState * pending, GstClockTime timeout)
1914 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1915 GstState old_pending;
1917 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1918 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1920 GST_OBJECT_LOCK (element);
1921 ret = GST_STATE_RETURN (element);
1922 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1923 gst_element_state_change_return_get_name (ret));
1925 /* we got an error, report immediately */
1926 if (ret == GST_STATE_CHANGE_FAILURE)
1929 /* we got no_preroll, report immediatly */
1930 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1933 /* no need to wait async if we are not async */
1934 if (ret != GST_STATE_CHANGE_ASYNC)
1937 old_pending = GST_STATE_PENDING (element);
1938 if (old_pending != GST_STATE_VOID_PENDING) {
1939 GTimeVal *timeval, abstimeout;
1942 if (timeout != GST_CLOCK_TIME_NONE) {
1943 glong add = timeout / 1000;
1948 /* make timeout absolute */
1949 g_get_current_time (&abstimeout);
1950 g_time_val_add (&abstimeout, add);
1951 timeval = &abstimeout;
1955 /* get cookie to detect state changes during waiting */
1956 cookie = element->state_cookie;
1958 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1959 "waiting for element to commit state");
1961 /* we have a pending state change, wait for it to complete */
1962 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1963 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1964 /* timeout triggered */
1965 ret = GST_STATE_CHANGE_ASYNC;
1967 if (cookie != element->state_cookie)
1970 /* could be success or failure */
1971 if (old_pending == GST_STATE (element)) {
1972 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1973 ret = GST_STATE_CHANGE_SUCCESS;
1975 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1976 ret = GST_STATE_CHANGE_FAILURE;
1979 /* if nothing is pending anymore we can return SUCCESS */
1980 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1981 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1982 ret = GST_STATE_CHANGE_SUCCESS;
1988 *state = GST_STATE (element);
1990 *pending = GST_STATE_PENDING (element);
1992 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1993 "state current: %s, pending: %s, result: %s",
1994 gst_element_state_get_name (GST_STATE (element)),
1995 gst_element_state_get_name (GST_STATE_PENDING (element)),
1996 gst_element_state_change_return_get_name (ret));
1997 GST_OBJECT_UNLOCK (element);
2004 *state = GST_STATE_VOID_PENDING;
2006 *pending = GST_STATE_VOID_PENDING;
2008 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2010 GST_OBJECT_UNLOCK (element);
2012 return GST_STATE_CHANGE_FAILURE;
2017 * gst_element_get_state:
2018 * @element: a #GstElement to get the state of.
2019 * @state: (out): a pointer to #GstState to hold the state. Can be %NULL.
2020 * @pending: (out): a pointer to #GstState to hold the pending state.
2022 * @timeout: a #GstClockTime to specify the timeout for an async
2023 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2025 * Gets the state of the element.
2027 * For elements that performed an ASYNC state change, as reported by
2028 * gst_element_set_state(), this function will block up to the
2029 * specified timeout value for the state change to complete.
2030 * If the element completes the state change or goes into
2031 * an error, this function returns immediately with a return value of
2032 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2034 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2035 * returns the current and pending state immediately.
2037 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2038 * successfully changed its state but is not able to provide data yet.
2039 * This mostly happens for live sources that only produce data in
2040 * %GST_STATE_PLAYING. While the state change return is equivalent to
2041 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2042 * some sink elements might not be able to complete their state change because
2043 * an element is not producing data to complete the preroll. When setting the
2044 * element to playing, the preroll will complete and playback will start.
2046 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2047 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2048 * element is still performing a state change or
2049 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2053 GstStateChangeReturn
2054 gst_element_get_state (GstElement * element,
2055 GstState * state, GstState * pending, GstClockTime timeout)
2057 GstElementClass *oclass;
2058 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2060 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2062 oclass = GST_ELEMENT_GET_CLASS (element);
2064 if (oclass->get_state)
2065 result = (oclass->get_state) (element, state, pending, timeout);
2071 * gst_element_abort_state:
2072 * @element: a #GstElement to abort the state of.
2074 * Abort the state change of the element. This function is used
2075 * by elements that do asynchronous state changes and find out
2076 * something is wrong.
2078 * This function should be called with the STATE_LOCK held.
2083 gst_element_abort_state (GstElement * element)
2087 #ifndef GST_DISABLE_GST_DEBUG
2091 g_return_if_fail (GST_IS_ELEMENT (element));
2093 GST_OBJECT_LOCK (element);
2094 pending = GST_STATE_PENDING (element);
2096 if (pending == GST_STATE_VOID_PENDING ||
2097 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2098 goto nothing_aborted;
2100 #ifndef GST_DISABLE_GST_DEBUG
2101 old_state = GST_STATE (element);
2103 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2104 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2105 gst_element_state_get_name (pending));
2109 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2111 GST_STATE_BROADCAST (element);
2112 GST_OBJECT_UNLOCK (element);
2118 GST_OBJECT_UNLOCK (element);
2124 * gst_element_continue_state:
2125 * @element: a #GstElement to continue the state change of.
2126 * @ret: The previous state return value
2128 * Commit the state change of the element and proceed to the next
2129 * pending state if any. This function is used
2130 * by elements that do asynchronous state changes.
2131 * The core will normally call this method automatically when an
2132 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2134 * If after calling this method the element still has not reached
2135 * the pending state, the next state change is performed.
2137 * This method is used internally and should normally not be called by plugins
2140 * Returns: The result of the commit state change.
2144 GstStateChangeReturn
2145 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2147 GstStateChangeReturn old_ret;
2148 GstState old_state, old_next;
2149 GstState current, next, pending;
2150 GstMessage *message;
2151 GstStateChange transition;
2153 GST_OBJECT_LOCK (element);
2154 old_ret = GST_STATE_RETURN (element);
2155 GST_STATE_RETURN (element) = ret;
2156 pending = GST_STATE_PENDING (element);
2158 /* check if there is something to commit */
2159 if (pending == GST_STATE_VOID_PENDING)
2160 goto nothing_pending;
2162 old_state = GST_STATE (element);
2163 /* this is the state we should go to next */
2164 old_next = GST_STATE_NEXT (element);
2165 /* update current state */
2166 current = GST_STATE (element) = old_next;
2168 /* see if we reached the final state */
2169 if (pending == current)
2172 next = GST_STATE_GET_NEXT (current, pending);
2173 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2175 GST_STATE_NEXT (element) = next;
2177 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2178 GST_OBJECT_UNLOCK (element);
2180 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2181 "committing state from %s to %s, pending %s, next %s",
2182 gst_element_state_get_name (old_state),
2183 gst_element_state_get_name (old_next),
2184 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2186 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2187 old_state, old_next, pending);
2188 gst_element_post_message (element, message);
2190 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2191 "continue state change %s to %s, final %s",
2192 gst_element_state_get_name (current),
2193 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2195 ret = gst_element_change_state (element, transition);
2201 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2202 GST_OBJECT_UNLOCK (element);
2207 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2208 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2210 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2211 "completed state change to %s", gst_element_state_get_name (pending));
2212 GST_OBJECT_UNLOCK (element);
2214 /* don't post silly messages with the same state. This can happen
2215 * when an element state is changed to what it already was. For bins
2216 * this can be the result of a lost state, which we check with the
2217 * previous return value.
2218 * We do signal the cond though as a _get_state() might be blocking
2220 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2221 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2222 "posting state-changed %s to %s",
2223 gst_element_state_get_name (old_state),
2224 gst_element_state_get_name (old_next));
2226 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2227 old_next, GST_STATE_VOID_PENDING);
2228 gst_element_post_message (element, message);
2231 GST_STATE_BROADCAST (element);
2238 * gst_element_lost_state_full:
2239 * @element: a #GstElement the state is lost of
2240 * @new_base_time: if a new base time should be distributed
2242 * Brings the element to the lost state. The current state of the
2243 * element is copied to the pending state so that any call to
2244 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2246 * An ASYNC_START message is posted with indication to distribute a new
2247 * base_time to the element when @new_base_time is %TRUE.
2248 * If the element was PLAYING, it will go to PAUSED. The element
2249 * will be restored to its PLAYING state by the parent pipeline when it
2252 * This is mostly used for elements that lost their preroll buffer
2253 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2254 * they will go to their pending state again when a new preroll buffer is
2255 * queued. This function can only be called when the element is currently
2256 * not in error or an async state change.
2258 * This function is used internally and should normally not be called from
2259 * plugins or applications.
2266 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2268 GstState old_state, new_state;
2269 GstMessage *message;
2271 g_return_if_fail (GST_IS_ELEMENT (element));
2273 GST_OBJECT_LOCK (element);
2274 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2277 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2278 goto only_async_start;
2280 old_state = GST_STATE (element);
2282 /* when we were PLAYING, the new state is PAUSED. We will also not
2283 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2284 * when we preroll. */
2285 if (old_state > GST_STATE_PAUSED)
2286 new_state = GST_STATE_PAUSED;
2288 new_state = old_state;
2290 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2291 "lost state of %s to %s", gst_element_state_get_name (old_state),
2292 gst_element_state_get_name (new_state));
2294 GST_STATE (element) = new_state;
2295 GST_STATE_NEXT (element) = new_state;
2296 GST_STATE_PENDING (element) = new_state;
2297 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2299 GST_ELEMENT_START_TIME (element) = 0;
2300 GST_OBJECT_UNLOCK (element);
2302 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2303 new_state, new_state, new_state);
2304 gst_element_post_message (element, message);
2307 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2308 gst_element_post_message (element, message);
2314 GST_OBJECT_UNLOCK (element);
2319 GST_OBJECT_UNLOCK (element);
2321 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2322 gst_element_post_message (element, message);
2328 * gst_element_lost_state:
2329 * @element: a #GstElement the state is lost of
2331 * Brings the element to the lost state. This function calls
2332 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2334 * This function is used internally and should normally not be called from
2335 * plugins or applications.
2340 gst_element_lost_state (GstElement * element)
2342 gst_element_lost_state_full (element, TRUE);
2346 * gst_element_set_state:
2347 * @element: a #GstElement to change state of.
2348 * @state: the element's new #GstState.
2350 * Sets the state of the element. This function will try to set the
2351 * requested state by going through all the intermediary states and calling
2352 * the class's state change function for each.
2354 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2355 * element will perform the remainder of the state change asynchronously in
2357 * An application can use gst_element_get_state() to wait for the completion
2358 * of the state change or it can wait for a state change message on the bus.
2360 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2361 * #GST_STATE_CHANGE_ASYNC.
2363 * Returns: Result of the state change using #GstStateChangeReturn.
2367 GstStateChangeReturn
2368 gst_element_set_state (GstElement * element, GstState state)
2370 GstElementClass *oclass;
2371 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2373 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2375 oclass = GST_ELEMENT_GET_CLASS (element);
2377 if (oclass->set_state)
2378 result = (oclass->set_state) (element, state);
2384 * default set state function, calculates the next state based
2385 * on current state and calls the change_state function
2387 static GstStateChangeReturn
2388 gst_element_set_state_func (GstElement * element, GstState state)
2390 GstState current, next, old_pending;
2391 GstStateChangeReturn ret;
2392 GstStateChange transition;
2393 GstStateChangeReturn old_ret;
2395 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2397 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2398 gst_element_state_get_name (state));
2400 /* state lock is taken to protect the set_state() and get_state()
2401 * procedures, it does not lock any variables. */
2402 GST_STATE_LOCK (element);
2404 /* now calculate how to get to the new state */
2405 GST_OBJECT_LOCK (element);
2406 old_ret = GST_STATE_RETURN (element);
2407 /* previous state change returned an error, remove all pending
2408 * and next states */
2409 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2410 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2411 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2412 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2415 current = GST_STATE (element);
2416 next = GST_STATE_NEXT (element);
2417 old_pending = GST_STATE_PENDING (element);
2419 /* this is the (new) state we should go to. TARGET is the last state we set on
2421 if (state != GST_STATE_TARGET (element)) {
2422 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2423 "setting target state to %s", gst_element_state_get_name (state));
2424 GST_STATE_TARGET (element) = state;
2425 /* increment state cookie so that we can track each state change. We only do
2426 * this if this is actually a new state change. */
2427 element->state_cookie++;
2429 GST_STATE_PENDING (element) = state;
2431 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2432 "current %s, old_pending %s, next %s, old return %s",
2433 gst_element_state_get_name (current),
2434 gst_element_state_get_name (old_pending),
2435 gst_element_state_get_name (next),
2436 gst_element_state_change_return_get_name (old_ret));
2438 /* if the element was busy doing a state change, we just update the
2439 * target state, it'll get to it async then. */
2440 if (old_pending != GST_STATE_VOID_PENDING) {
2441 /* upwards state change will happen ASYNC */
2442 if (old_pending <= state)
2444 /* element is going to this state already */
2445 else if (next == state)
2447 /* element was performing an ASYNC upward state change and
2448 * we request to go downward again. Start from the next pending
2450 else if (next > state
2451 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2455 next = GST_STATE_GET_NEXT (current, state);
2456 /* now we store the next state */
2457 GST_STATE_NEXT (element) = next;
2458 /* mark busy, we need to check that there is actually a state change
2459 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2460 * the default element change_state function has no way to know what the
2461 * old value was... could consider this a FIXME...*/
2462 if (current != next)
2463 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2465 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2467 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2468 "%s: setting state from %s to %s",
2469 (next != state ? "intermediate" : "final"),
2470 gst_element_state_get_name (current), gst_element_state_get_name (next));
2472 /* now signal any waiters, they will error since the cookie was incremented */
2473 GST_STATE_BROADCAST (element);
2475 GST_OBJECT_UNLOCK (element);
2477 ret = gst_element_change_state (element, transition);
2479 GST_STATE_UNLOCK (element);
2481 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2482 gst_element_state_change_return_get_name (ret));
2488 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2489 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2490 "element was busy with async state change");
2491 GST_OBJECT_UNLOCK (element);
2493 GST_STATE_UNLOCK (element);
2495 return GST_STATE_CHANGE_ASYNC;
2500 * gst_element_change_state:
2501 * @element: a #GstElement
2502 * @transition: the requested transition
2504 * Perform @transition on @element.
2506 * This function must be called with STATE_LOCK held and is mainly used
2509 * Returns: the #GstStateChangeReturn of the state transition.
2511 GstStateChangeReturn
2512 gst_element_change_state (GstElement * element, GstStateChange transition)
2514 GstElementClass *oclass;
2515 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2517 oclass = GST_ELEMENT_GET_CLASS (element);
2519 /* call the state change function so it can set the state */
2520 if (oclass->change_state)
2521 ret = (oclass->change_state) (element, transition);
2523 ret = GST_STATE_CHANGE_FAILURE;
2526 case GST_STATE_CHANGE_FAILURE:
2527 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2528 "have FAILURE change_state return");
2529 /* state change failure */
2530 gst_element_abort_state (element);
2532 case GST_STATE_CHANGE_ASYNC:
2536 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2537 "element will change state ASYNC");
2539 target = GST_STATE_TARGET (element);
2541 if (target > GST_STATE_READY)
2544 /* else we just continue the state change downwards */
2545 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2546 "forcing commit state %s <= %s",
2547 gst_element_state_get_name (target),
2548 gst_element_state_get_name (GST_STATE_READY));
2550 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2553 case GST_STATE_CHANGE_SUCCESS:
2554 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2555 "element changed state SUCCESS");
2556 /* we can commit the state now which will proceeed to
2558 ret = gst_element_continue_state (element, ret);
2560 case GST_STATE_CHANGE_NO_PREROLL:
2561 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2562 "element changed state NO_PREROLL");
2563 /* we can commit the state now which will proceeed to
2565 ret = gst_element_continue_state (element, ret);
2568 goto invalid_return;
2571 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2576 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2584 GST_OBJECT_LOCK (element);
2585 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2586 g_critical ("%s: unknown return value %d from a state change function",
2587 GST_ELEMENT_NAME (element), ret);
2589 /* we are in error now */
2590 ret = GST_STATE_CHANGE_FAILURE;
2591 GST_STATE_RETURN (element) = ret;
2592 GST_OBJECT_UNLOCK (element);
2598 /* gst_iterator_fold functions for pads_activate
2599 * Note how we don't stop the iterator when we fail an activation. This is
2600 * probably a FIXME since when one pad activation fails, we don't want to
2601 * continue our state change. */
2603 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2605 if (!gst_pad_set_active (pad, *active))
2606 g_value_set_boolean (ret, FALSE);
2608 /* unref the object that was reffed for us by _fold */
2609 gst_object_unref (pad);
2613 /* set the caps on the pad to NULL */
2615 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2617 gst_pad_set_caps (pad, NULL);
2618 gst_object_unref (pad);
2622 /* returns false on error or early cutout (will never happen because the fold
2623 * function always returns TRUE, see FIXME above) of the fold, true if all
2624 * pads in @iter were (de)activated successfully. */
2626 iterator_activate_fold_with_resync (GstIterator * iter,
2627 GstIteratorFoldFunction func, gpointer user_data)
2629 GstIteratorResult ires;
2632 /* no need to unset this later, it's just a boolean */
2633 g_value_init (&ret, G_TYPE_BOOLEAN);
2634 g_value_set_boolean (&ret, TRUE);
2637 ires = gst_iterator_fold (iter, func, &ret, user_data);
2639 case GST_ITERATOR_RESYNC:
2640 /* need to reset the result again */
2641 g_value_set_boolean (&ret, TRUE);
2642 gst_iterator_resync (iter);
2644 case GST_ITERATOR_DONE:
2645 /* all pads iterated, return collected value */
2648 /* iterator returned _ERROR or premature end with _OK,
2649 * mark an error and exit */
2650 g_value_set_boolean (&ret, FALSE);
2655 /* return collected value */
2656 return g_value_get_boolean (&ret);
2659 /* is called with STATE_LOCK
2661 * Pads are activated from source pads to sinkpads.
2664 gst_element_pads_activate (GstElement * element, gboolean active)
2669 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2670 "pads_activate with active %d", active);
2672 iter = gst_element_iterate_src_pads (element);
2674 iterator_activate_fold_with_resync (iter,
2675 (GstIteratorFoldFunction) activate_pads, &active);
2676 gst_iterator_free (iter);
2677 if (G_UNLIKELY (!res))
2680 iter = gst_element_iterate_sink_pads (element);
2682 iterator_activate_fold_with_resync (iter,
2683 (GstIteratorFoldFunction) activate_pads, &active);
2684 gst_iterator_free (iter);
2685 if (G_UNLIKELY (!res))
2689 /* clear the caps on all pads, this should never fail */
2690 iter = gst_element_iterate_pads (element);
2692 iterator_activate_fold_with_resync (iter,
2693 (GstIteratorFoldFunction) clear_caps, &active);
2694 gst_iterator_free (iter);
2695 if (G_UNLIKELY (!res))
2699 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2700 "pads_activate successful");
2707 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2708 "source pads_activate failed");
2713 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2714 "sink pads_activate failed");
2719 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2720 "failed to clear caps on pads");
2725 /* is called with STATE_LOCK */
2726 static GstStateChangeReturn
2727 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2729 GstState state, next;
2730 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2733 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2735 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2736 next = GST_STATE_TRANSITION_NEXT (transition);
2738 /* if the element already is in the given state, we just return success */
2739 if (next == GST_STATE_VOID_PENDING || state == next)
2742 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2743 "default handler tries setting state from %s to %s (%04x)",
2744 gst_element_state_get_name (state),
2745 gst_element_state_get_name (next), transition);
2747 switch (transition) {
2748 case GST_STATE_CHANGE_NULL_TO_READY:
2750 case GST_STATE_CHANGE_READY_TO_PAUSED:
2751 if (!gst_element_pads_activate (element, TRUE)) {
2752 result = GST_STATE_CHANGE_FAILURE;
2755 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2757 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2759 case GST_STATE_CHANGE_PAUSED_TO_READY:
2760 case GST_STATE_CHANGE_READY_TO_NULL:
2761 /* deactivate pads in both cases, since they are activated on
2762 ready->paused but the element might not have made it to paused */
2763 if (!gst_element_pads_activate (element, FALSE)) {
2764 result = GST_STATE_CHANGE_FAILURE;
2766 gst_element_set_base_time (element, 0);
2769 /* In null state release the reference to the clock */
2770 GST_OBJECT_LOCK (element);
2771 clock_p = &element->clock;
2772 gst_object_replace ((GstObject **) clock_p, NULL);
2773 GST_OBJECT_UNLOCK (element);
2776 /* this will catch real but unhandled state changes;
2777 * can only be caused by:
2778 * - a new state was added
2779 * - somehow the element was asked to jump across an intermediate state
2781 g_warning ("Unhandled state change from %s to %s",
2782 gst_element_state_get_name (state),
2783 gst_element_state_get_name (next));
2790 GST_OBJECT_LOCK (element);
2791 result = GST_STATE_RETURN (element);
2792 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2793 "element is already in the %s state",
2794 gst_element_state_get_name (state));
2795 GST_OBJECT_UNLOCK (element);
2802 * gst_element_get_factory:
2803 * @element: a #GstElement to request the element factory of.
2805 * Retrieves the factory that was used to create this element.
2807 * Returns: the #GstElementFactory used for creating this element.
2808 * no refcounting is needed.
2811 gst_element_get_factory (GstElement * element)
2813 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2815 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2819 gst_element_dispose (GObject * object)
2821 GstElement *element = GST_ELEMENT_CAST (object);
2825 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2827 if (GST_STATE (element) != GST_STATE_NULL)
2830 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2831 "removing %d pads", g_list_length (element->pads));
2832 /* first we break all our links with the outside */
2833 while (element->pads && element->pads->data) {
2834 /* don't call _remove_pad with NULL */
2835 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2837 if (G_UNLIKELY (element->pads != NULL)) {
2838 g_critical ("could not remove pads from element %s",
2839 GST_STR_NULL (GST_OBJECT_NAME (object)));
2842 GST_OBJECT_LOCK (element);
2843 clock_p = &element->clock;
2844 bus_p = &element->bus;
2845 gst_object_replace ((GstObject **) clock_p, NULL);
2846 gst_object_replace ((GstObject **) bus_p, NULL);
2847 GST_OBJECT_UNLOCK (element);
2849 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2851 G_OBJECT_CLASS (parent_class)->dispose (object);
2860 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2862 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2864 "You need to explicitly set elements to the NULL state before\n"
2865 "dropping the final reference, to allow them to clean up.\n"
2866 "This problem may also be caused by a refcounting bug in the\n"
2867 "application or some element.\n",
2868 GST_OBJECT_NAME (element),
2869 gst_element_state_get_name (GST_STATE (element)),
2870 is_locked ? " (locked)" : "");
2876 gst_element_finalize (GObject * object)
2878 GstElement *element = GST_ELEMENT_CAST (object);
2880 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2882 GST_STATE_LOCK (element);
2883 if (element->state_cond)
2884 g_cond_free (element->state_cond);
2885 element->state_cond = NULL;
2886 GST_STATE_UNLOCK (element);
2887 g_static_rec_mutex_free (element->state_lock);
2888 g_free (element->state_lock);
2889 element->state_lock = NULL;
2891 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2893 G_OBJECT_CLASS (parent_class)->finalize (object);
2896 #ifndef GST_DISABLE_LOADSAVE
2898 * gst_element_save_thyself:
2899 * @element: a #GstElement to save.
2900 * @parent: the xml parent node.
2902 * Saves the element as part of the given XML structure.
2904 * Returns: the new #xmlNodePtr.
2907 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2910 GstElementClass *oclass;
2911 GParamSpec **specs, *spec;
2914 GValue value = { 0, };
2915 GstElement *element;
2917 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2919 element = GST_ELEMENT_CAST (object);
2921 oclass = GST_ELEMENT_GET_CLASS (element);
2923 xmlNewChild (parent, NULL, (xmlChar *) "name",
2924 (xmlChar *) GST_ELEMENT_NAME (element));
2926 if (oclass->elementfactory != NULL) {
2927 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2929 xmlNewChild (parent, NULL, (xmlChar *) "type",
2930 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2934 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2936 for (i = 0; i < nspecs; i++) {
2938 if (spec->flags & G_PARAM_READABLE) {
2942 g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (spec));
2944 g_object_get_property (G_OBJECT (element), spec->name, &value);
2945 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2946 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2948 if (G_IS_PARAM_SPEC_STRING (spec))
2949 contents = g_value_dup_string (&value);
2950 else if (G_IS_PARAM_SPEC_ENUM (spec))
2951 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2952 else if (G_IS_PARAM_SPEC_INT64 (spec))
2953 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2954 g_value_get_int64 (&value));
2955 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
2956 if (g_value_get_boxed (&value) != NULL) {
2957 contents = g_strdup_value_contents (&value);
2959 contents = g_strdup ("NULL");
2962 contents = g_strdup_value_contents (&value);
2964 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2967 g_value_unset (&value);
2973 pads = g_list_last (GST_ELEMENT_PADS (element));
2976 GstPad *pad = GST_PAD_CAST (pads->data);
2978 /* figure out if it's a direct pad or a ghostpad */
2979 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
2980 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
2982 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
2984 pads = g_list_previous (pads);
2991 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
2993 xmlNodePtr children;
2994 GstElement *element;
2996 gchar *value = NULL;
2998 element = GST_ELEMENT_CAST (object);
2999 g_return_if_fail (element != NULL);
3002 children = self->xmlChildrenNode;
3004 if (!strcmp ((char *) children->name, "param")) {
3005 xmlNodePtr child = children->xmlChildrenNode;
3008 if (!strcmp ((char *) child->name, "name")) {
3009 name = (gchar *) xmlNodeGetContent (child);
3010 } else if (!strcmp ((char *) child->name, "value")) {
3011 value = (gchar *) xmlNodeGetContent (child);
3013 child = child->next;
3015 /* FIXME: can this just be g_object_set ? */
3016 gst_util_set_object_arg (G_OBJECT (element), name, value);
3017 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3021 children = children->next;
3025 children = self->xmlChildrenNode;
3027 if (!strcmp ((char *) children->name, "pad")) {
3028 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3030 children = children->next;
3033 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3034 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3036 #endif /* GST_DISABLE_LOADSAVE */
3039 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3043 g_return_if_fail (GST_IS_ELEMENT (element));
3045 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3047 GST_OBJECT_LOCK (element);
3048 bus_p = &GST_ELEMENT_BUS (element);
3049 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3050 GST_OBJECT_UNLOCK (element);
3054 * gst_element_set_bus:
3055 * @element: a #GstElement to set the bus of.
3056 * @bus: the #GstBus to set.
3058 * Sets the bus of the element. Increases the refcount on the bus.
3059 * For internal use only, unless you're testing elements.
3064 gst_element_set_bus (GstElement * element, GstBus * bus)
3066 GstElementClass *oclass;
3068 g_return_if_fail (GST_IS_ELEMENT (element));
3070 oclass = GST_ELEMENT_GET_CLASS (element);
3072 if (oclass->set_bus)
3073 oclass->set_bus (element, bus);
3077 * gst_element_get_bus:
3078 * @element: a #GstElement to get the bus of.
3080 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3081 * bus for the application.
3083 * Returns: the element's #GstBus. unref after usage.
3088 gst_element_get_bus (GstElement * element)
3090 GstBus *result = NULL;
3092 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3094 GST_OBJECT_LOCK (element);
3095 if ((result = GST_ELEMENT_BUS (element)))
3096 gst_object_ref (result);
3097 GST_OBJECT_UNLOCK (element);
3099 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,