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 element->state_lock = g_slice_new (GStaticRecMutex);
289 g_static_rec_mutex_init (element->state_lock);
290 element->state_cond = g_cond_new ();
294 * gst_element_release_request_pad:
295 * @element: a #GstElement to release the request pad of.
296 * @pad: the #GstPad to release.
298 * Makes the element free the previously requested pad as obtained
299 * with gst_element_get_request_pad().
301 * This does not unref the pad. If the pad was created by using
302 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
303 * followed by gst_object_unref() to free the @pad.
308 gst_element_release_request_pad (GstElement * element, GstPad * pad)
310 GstElementClass *oclass;
312 g_return_if_fail (GST_IS_ELEMENT (element));
313 g_return_if_fail (GST_IS_PAD (pad));
315 oclass = GST_ELEMENT_GET_CLASS (element);
317 /* if the element implements a custom release function we call that, else we
318 * simply remove the pad from the element */
319 if (oclass->release_pad)
320 (oclass->release_pad) (element, pad);
322 gst_element_remove_pad (element, pad);
326 * gst_element_requires_clock:
327 * @element: a #GstElement to query
329 * Query if the element requires a clock.
331 * Returns: %TRUE if the element requires a clock
336 gst_element_requires_clock (GstElement * element)
340 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
342 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
348 * gst_element_provides_clock:
349 * @element: a #GstElement to query
351 * Query if the element provides a clock. A #GstClock provided by an
352 * element can be used as the global #GstClock for the pipeline.
353 * An element that can provide a clock is only required to do so in the PAUSED
354 * state, this means when it is fully negotiated and has allocated the resources
355 * to operate the clock.
357 * Returns: %TRUE if the element provides a clock
362 gst_element_provides_clock (GstElement * element)
366 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
368 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
374 * gst_element_provide_clock:
375 * @element: a #GstElement to query
377 * Get the clock provided by the given element.
378 * <note>An element is only required to provide a clock in the PAUSED
379 * state. Some elements can provide a clock in other states.</note>
381 * Returns: (transfer full): the GstClock provided by the element or %NULL
382 * if no clock could be provided. Unref after usage.
387 gst_element_provide_clock (GstElement * element)
389 GstClock *result = NULL;
390 GstElementClass *oclass;
392 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
394 oclass = GST_ELEMENT_GET_CLASS (element);
396 if (oclass->provide_clock)
397 result = oclass->provide_clock (element);
403 * gst_element_set_clock:
404 * @element: a #GstElement to set the clock for.
405 * @clock: the #GstClock to set for the element.
407 * Sets the clock for the element. This function increases the
408 * refcount on the clock. Any previously set clock on the object
411 * Returns: %TRUE if the element accepted the clock. An element can refuse a
412 * clock when it, for example, is not able to slave its internal clock to the
413 * @clock or when it requires a specific clock to operate.
418 gst_element_set_clock (GstElement * element, GstClock * clock)
420 GstElementClass *oclass;
424 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
425 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
427 oclass = GST_ELEMENT_GET_CLASS (element);
429 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
431 if (oclass->set_clock)
432 res = oclass->set_clock (element, clock);
435 /* only update the clock pointer if the element accepted the clock */
436 GST_OBJECT_LOCK (element);
437 clock_p = &element->clock;
438 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
439 GST_OBJECT_UNLOCK (element);
445 * gst_element_get_clock:
446 * @element: a #GstElement to get the clock of.
448 * Gets the currently configured clock of the element. This is the clock as was
449 * last set with gst_element_set_clock().
451 * Returns: (transfer full): the #GstClock of the element. unref after usage.
456 gst_element_get_clock (GstElement * element)
460 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
462 GST_OBJECT_LOCK (element);
463 if ((result = element->clock))
464 gst_object_ref (result);
465 GST_OBJECT_UNLOCK (element);
471 * gst_element_set_base_time:
472 * @element: a #GstElement.
473 * @time: the base time to set.
475 * Set the base time of an element. See gst_element_get_base_time().
480 gst_element_set_base_time (GstElement * element, GstClockTime time)
484 g_return_if_fail (GST_IS_ELEMENT (element));
486 GST_OBJECT_LOCK (element);
487 old = element->base_time;
488 element->base_time = time;
489 GST_OBJECT_UNLOCK (element);
491 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
492 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
493 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
497 * gst_element_get_base_time:
498 * @element: a #GstElement.
500 * Returns the base time of the element. The base time is the
501 * absolute time of the clock when this element was last put to
502 * PLAYING. Subtracting the base time from the clock time gives
503 * the running time of the element.
505 * Returns: the base time of the element.
510 gst_element_get_base_time (GstElement * element)
514 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
516 GST_OBJECT_LOCK (element);
517 result = element->base_time;
518 GST_OBJECT_UNLOCK (element);
524 * gst_element_set_start_time:
525 * @element: a #GstElement.
526 * @time: the base time to set.
528 * Set the start time of an element. The start time of the element is the
529 * running time of the element when it last went to the PAUSED state. In READY
530 * or after a flushing seek, it is set to 0.
532 * Toplevel elements like #GstPipeline will manage the start_time and
533 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
534 * on such a toplevel element will disable the distribution of the base_time to
535 * the children and can be useful if the application manages the base_time
536 * itself, for example if you want to synchronize capture from multiple
537 * pipelines, and you can also ensure that the pipelines have the same clock.
544 gst_element_set_start_time (GstElement * element, GstClockTime time)
548 g_return_if_fail (GST_IS_ELEMENT (element));
550 GST_OBJECT_LOCK (element);
551 old = GST_ELEMENT_START_TIME (element);
552 GST_ELEMENT_START_TIME (element) = time;
553 GST_OBJECT_UNLOCK (element);
555 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
556 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
557 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
561 * gst_element_get_start_time:
562 * @element: a #GstElement.
564 * Returns the start time of the element. The start time is the
565 * running time of the clock when this element was last put to PAUSED.
567 * Usually the start_time is managed by a toplevel element such as
572 * Returns: the start time of the element.
577 gst_element_get_start_time (GstElement * element)
581 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
583 GST_OBJECT_LOCK (element);
584 result = GST_ELEMENT_START_TIME (element);
585 GST_OBJECT_UNLOCK (element);
591 * gst_element_is_indexable:
592 * @element: a #GstElement.
594 * Queries if the element can be indexed.
596 * Returns: TRUE if the element can be indexed.
601 gst_element_is_indexable (GstElement * element)
605 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
607 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
613 * gst_element_set_index:
614 * @element: a #GstElement.
615 * @index: (transfer none): a #GstIndex.
617 * Set @index on the element. The refcount of the index
618 * will be increased, any previously set index is unreffed.
623 gst_element_set_index (GstElement * element, GstIndex * index)
625 GstElementClass *oclass;
627 g_return_if_fail (GST_IS_ELEMENT (element));
628 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
630 oclass = GST_ELEMENT_GET_CLASS (element);
632 if (oclass->set_index)
633 oclass->set_index (element, index);
637 * gst_element_get_index:
638 * @element: a #GstElement.
640 * Gets the index from the element.
642 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
643 * element. unref after usage.
648 gst_element_get_index (GstElement * element)
650 GstElementClass *oclass;
651 GstIndex *result = NULL;
653 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
655 oclass = GST_ELEMENT_GET_CLASS (element);
657 if (oclass->get_index)
658 result = oclass->get_index (element);
664 * gst_element_add_pad:
665 * @element: a #GstElement to add the pad to.
666 * @pad: (transfer full): the #GstPad to add to the element.
668 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
669 * see gst_object_set_parent() for refcounting information.
671 * Pads are not automatically activated so elements should perform the needed
672 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
673 * state. See gst_pad_set_active() for more information about activating pads.
675 * The pad and the element should be unlocked when calling this function.
677 * This function will emit the #GstElement::pad-added signal on the element.
679 * Returns: %TRUE if the pad could be added. This function can fail when
680 * a pad with the same name already existed or the pad already had another
686 gst_element_add_pad (GstElement * element, GstPad * pad)
691 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
692 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
694 /* locking pad to look at the name */
695 GST_OBJECT_LOCK (pad);
696 pad_name = g_strdup (GST_PAD_NAME (pad));
697 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
698 GST_STR_NULL (pad_name));
699 flushing = GST_PAD_IS_FLUSHING (pad);
700 GST_OBJECT_UNLOCK (pad);
702 /* then check to see if there's already a pad by that name here */
703 GST_OBJECT_LOCK (element);
704 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
707 /* try to set the pad's parent */
708 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
709 GST_OBJECT_CAST (element))))
712 /* check for flushing pads */
713 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
714 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
715 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
716 "use gst_pad_set_active(pad,TRUE) before adding it.",
717 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
719 GST_OBJECT_LOCK (pad);
720 GST_PAD_UNSET_FLUSHING (pad);
721 GST_OBJECT_UNLOCK (pad);
726 /* add it to the list */
727 switch (gst_pad_get_direction (pad)) {
729 element->srcpads = g_list_prepend (element->srcpads, pad);
730 element->numsrcpads++;
733 element->sinkpads = g_list_prepend (element->sinkpads, pad);
734 element->numsinkpads++;
739 element->pads = g_list_prepend (element->pads, pad);
741 element->pads_cookie++;
742 GST_OBJECT_UNLOCK (element);
744 /* emit the PAD_ADDED signal */
745 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
752 g_critical ("Padname %s is not unique in element %s, not adding",
753 pad_name, GST_ELEMENT_NAME (element));
754 GST_OBJECT_UNLOCK (element);
761 ("Pad %s already has parent when trying to add to element %s",
762 pad_name, GST_ELEMENT_NAME (element));
763 GST_OBJECT_UNLOCK (element);
769 GST_OBJECT_LOCK (pad);
771 ("Trying to add pad %s to element %s, but it has no direction",
772 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
773 GST_OBJECT_UNLOCK (pad);
774 GST_OBJECT_UNLOCK (element);
780 * gst_element_remove_pad:
781 * @element: a #GstElement to remove pad from.
782 * @pad: (transfer none): the #GstPad to remove from the element.
784 * Removes @pad from @element. @pad will be destroyed if it has not been
785 * referenced elsewhere using gst_object_unparent().
787 * This function is used by plugin developers and should not be used
788 * by applications. Pads that were dynamically requested from elements
789 * with gst_element_get_request_pad() should be released with the
790 * gst_element_release_request_pad() function instead.
792 * Pads are not automatically deactivated so elements should perform the needed
793 * steps to deactivate the pad in case this pad is removed in the PAUSED or
794 * PLAYING state. See gst_pad_set_active() for more information about
797 * The pad and the element should be unlocked when calling this function.
799 * This function will emit the #GstElement::pad-removed signal on the element.
801 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
802 * pad does not belong to the provided element.
807 gst_element_remove_pad (GstElement * element, GstPad * pad)
811 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
812 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
814 /* locking pad to look at the name and parent */
815 GST_OBJECT_LOCK (pad);
816 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
817 GST_STR_NULL (GST_PAD_NAME (pad)));
819 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
821 GST_OBJECT_UNLOCK (pad);
824 if ((peer = gst_pad_get_peer (pad))) {
825 /* window for MT unsafeness, someone else could unlink here
826 * and then we call unlink with wrong pads. The unlink
827 * function would catch this and safely return failed. */
828 if (GST_PAD_IS_SRC (pad))
829 gst_pad_unlink (pad, peer);
831 gst_pad_unlink (peer, pad);
833 gst_object_unref (peer);
836 GST_OBJECT_LOCK (element);
837 /* remove it from the list */
838 switch (gst_pad_get_direction (pad)) {
840 element->srcpads = g_list_remove (element->srcpads, pad);
841 element->numsrcpads--;
844 element->sinkpads = g_list_remove (element->sinkpads, pad);
845 element->numsinkpads--;
848 g_critical ("Removing pad without direction???");
851 element->pads = g_list_remove (element->pads, pad);
853 element->pads_cookie++;
854 GST_OBJECT_UNLOCK (element);
856 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
857 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
859 gst_object_unparent (GST_OBJECT_CAST (pad));
866 /* FIXME, locking order? */
867 GST_OBJECT_LOCK (element);
868 g_critical ("Padname %s:%s does not belong to element %s when removing",
869 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
870 GST_OBJECT_UNLOCK (element);
871 GST_OBJECT_UNLOCK (pad);
877 * gst_element_no_more_pads:
878 * @element: a #GstElement
880 * Use this function to signal that the element does not expect any more pads
881 * to show up in the current pipeline. This function should be called whenever
882 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
883 * pad templates use this in combination with autopluggers to figure out that
884 * the element is done initializing its pads.
886 * This function emits the #GstElement::no-more-pads signal.
891 gst_element_no_more_pads (GstElement * element)
893 g_return_if_fail (GST_IS_ELEMENT (element));
895 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
899 pad_compare_name (GstPad * pad1, const gchar * name)
903 GST_OBJECT_LOCK (pad1);
904 result = strcmp (GST_PAD_NAME (pad1), name);
905 GST_OBJECT_UNLOCK (pad1);
911 * gst_element_get_static_pad:
912 * @element: a #GstElement to find a static pad of.
913 * @name: the name of the static #GstPad to retrieve.
915 * Retrieves a pad from @element by name. This version only retrieves
916 * already-existing (i.e. 'static') pads.
918 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
924 gst_element_get_static_pad (GstElement * element, const gchar * name)
927 GstPad *result = NULL;
929 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
930 g_return_val_if_fail (name != NULL, NULL);
932 GST_OBJECT_LOCK (element);
934 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
936 result = GST_PAD_CAST (find->data);
937 gst_object_ref (result);
940 if (result == NULL) {
941 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
942 name, GST_ELEMENT_NAME (element));
944 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
945 GST_ELEMENT_NAME (element), name);
947 GST_OBJECT_UNLOCK (element);
953 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
954 const gchar * name, const GstCaps * caps)
956 GstPad *newpad = NULL;
957 GstElementClass *oclass;
959 oclass = GST_ELEMENT_GET_CLASS (element);
961 #ifndef G_DISABLE_CHECKS
962 /* Some sanity checking here */
966 /* Is this the template name? */
967 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
968 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
970 const gchar *str, *data;
973 /* Otherwise check if it's a valid name for the name template */
974 str = strchr (templ->name_template, '%');
975 g_return_val_if_fail (str != NULL, NULL);
976 g_return_val_if_fail (strncmp (templ->name_template, name,
977 str - templ->name_template) == 0, NULL);
978 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
980 data = name + (str - templ->name_template);
982 /* Can either be %s or %d or %u, do sanity checking for %d */
983 if (*(str + 1) == 'd') {
987 tmp = g_ascii_strtoll (data, &endptr, 10);
988 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
989 && *endptr == '\0', NULL);
990 } else if (*(str + 1) == 'u') {
994 tmp = g_ascii_strtoull (data, &endptr, 10);
995 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
999 pad = gst_element_get_static_pad (element, name);
1001 gst_object_unref (pad);
1002 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1003 g_critical ("Element %s already has a pad named %s, the behaviour of "
1004 " gst_element_get_request_pad() for existing pads is undefined!",
1005 GST_ELEMENT_NAME (element), name);
1010 if (oclass->request_new_pad)
1011 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1014 gst_object_ref (newpad);
1020 * gst_element_get_request_pad:
1021 * @element: a #GstElement to find a request pad of.
1022 * @name: the name of the request #GstPad to retrieve.
1024 * Retrieves a pad from the element by name. This version only retrieves
1025 * request pads. The pad should be released with
1026 * gst_element_release_request_pad().
1028 * This method is slow and will be deprecated in the future. New code should
1029 * use gst_element_request_pad() with the requested template.
1031 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1032 * Release after usage.
1035 gst_element_get_request_pad (GstElement * element, const gchar * name)
1037 GstPadTemplate *templ = NULL;
1039 const gchar *req_name = NULL;
1040 gboolean templ_found = FALSE;
1043 gchar *str, *endptr = NULL;
1044 GstElementClass *class;
1046 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1047 g_return_val_if_fail (name != NULL, NULL);
1049 class = GST_ELEMENT_GET_CLASS (element);
1051 /* if the name contains a %, we assume it's the complete template name. Get
1052 * the template and try to get a pad */
1053 if (strstr (name, "%")) {
1054 templ = gst_element_class_get_request_pad_template (class, name);
1059 /* there is no % in the name, try to find a matching template */
1060 list = class->padtemplates;
1061 while (!templ_found && list) {
1062 templ = (GstPadTemplate *) list->data;
1063 if (templ->presence == GST_PAD_REQUEST) {
1064 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1065 templ->name_template);
1066 /* see if we find an exact match */
1067 if (strcmp (name, templ->name_template) == 0) {
1072 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1073 and %d and %u, occurring at the end of the name_template, are the only
1075 else if ((str = strchr (templ->name_template, '%'))
1076 && strncmp (templ->name_template, name,
1077 str - templ->name_template) == 0
1078 && strlen (name) > str - templ->name_template) {
1079 data = name + (str - templ->name_template);
1080 if (*(str + 1) == 'd') {
1084 tmp = strtol (data, &endptr, 10);
1085 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1091 } else if (*(str + 1) == 'u') {
1095 tmp = strtoul (data, &endptr, 10);
1096 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1116 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1122 * gst_element_request_pad:
1123 * @element: a #GstElement to find a request pad of.
1124 * @templ: a #GstPadTemplate of which we want a pad of.
1125 * @name: (transfer none) (allow-none): the name of the request #GstPad
1126 * to retrieve. Can be %NULL.
1127 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1128 * request. Can be %NULL.
1130 * Retrieves a request pad from the element according to the provided template.
1132 * If the @caps are specified and the element implements thew new
1133 * request_new_pad_full virtual method, the element will use them to select
1134 * which pad to create.
1136 * The pad should be released with gst_element_release_request_pad().
1138 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1139 * Release after usage.
1144 gst_element_request_pad (GstElement * element,
1145 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1147 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1148 g_return_val_if_fail (templ != NULL, NULL);
1150 return _gst_element_request_pad (element, templ, name, caps);
1153 static GstIterator *
1154 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1156 GstIterator *result;
1158 GST_OBJECT_LOCK (element);
1159 result = gst_iterator_new_list (GST_TYPE_PAD,
1160 GST_OBJECT_GET_LOCK (element),
1161 &element->pads_cookie, padlist, (GObject *) element, NULL);
1162 GST_OBJECT_UNLOCK (element);
1168 * gst_element_iterate_pads:
1169 * @element: a #GstElement to iterate pads of.
1171 * Retrieves an iterattor of @element's pads. The iterator should
1172 * be freed after usage.
1174 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1180 gst_element_iterate_pads (GstElement * element)
1182 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1184 return gst_element_iterate_pad_list (element, &element->pads);
1188 * gst_element_iterate_src_pads:
1189 * @element: a #GstElement.
1191 * Retrieves an iterator of @element's source pads.
1193 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1199 gst_element_iterate_src_pads (GstElement * element)
1201 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1203 return gst_element_iterate_pad_list (element, &element->srcpads);
1207 * gst_element_iterate_sink_pads:
1208 * @element: a #GstElement.
1210 * Retrieves an iterator of @element's sink pads.
1212 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1218 gst_element_iterate_sink_pads (GstElement * element)
1220 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1222 return gst_element_iterate_pad_list (element, &element->sinkpads);
1226 * gst_element_class_add_pad_template:
1227 * @klass: the #GstElementClass to add the pad template to.
1228 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1230 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1231 * functions of classes. If a pad template with the same name as an already
1232 * existing one is added the old one is replaced by the new one.
1236 gst_element_class_add_pad_template (GstElementClass * klass,
1237 GstPadTemplate * templ)
1239 GList *template_list = klass->padtemplates;
1241 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1242 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1244 /* If we already have a pad template with the same name replace the
1246 while (template_list) {
1247 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1249 /* Found pad with the same name, replace and return */
1250 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1251 gst_object_unref (padtempl);
1252 template_list->data = templ;
1255 template_list = g_list_next (template_list);
1258 /* Take ownership of the floating ref */
1259 g_object_ref_sink (templ);
1261 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1262 klass->numpadtemplates++;
1266 * gst_element_class_add_metadata:
1267 * @klass: class to set metadata for
1268 * @key: the key to set
1269 * @value: the value to set
1271 * Set @key with @value as metadata in @klass.
1274 gst_element_class_add_metadata (GstElementClass * klass,
1275 const gchar * key, const gchar * value)
1277 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1278 g_return_if_fail (key != NULL);
1279 g_return_if_fail (value != NULL);
1281 gst_structure_set ((GstStructure *) klass->metadata,
1282 key, G_TYPE_STRING, value, NULL);
1286 * gst_element_class_set_metadata:
1287 * @klass: class to set metadata for
1288 * @longname: The long English name of the element. E.g. "File Sink"
1289 * @classification: String describing the type of element, as an unordered list
1290 * separated with slashes ('/'). See draft-klass.txt of the design docs
1291 * for more details and common types. E.g: "Sink/File"
1292 * @description: Sentence describing the purpose of the element.
1293 * E.g: "Write stream to a file"
1294 * @author: Name and contact details of the author(s). Use \n to separate
1295 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1297 * Sets the detailed information for a #GstElementClass.
1298 * <note>This function is for use in _class_init functions only.</note>
1301 gst_element_class_set_metadata (GstElementClass * klass,
1302 const gchar * longname, const gchar * classification,
1303 const gchar * description, const gchar * author)
1305 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1307 gst_structure_set ((GstStructure *) klass->metadata,
1308 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1309 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1310 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1311 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1315 * gst_element_class_get_metadata:
1316 * @klass: class to get metadata for
1317 * @key: the key to get
1319 * Get metadata with @key in @klass.
1321 * Returns: the metadata for @key.
1323 G_CONST_RETURN gchar *
1324 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1326 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1327 g_return_val_if_fail (key != NULL, NULL);
1329 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1333 * gst_element_class_get_pad_template_list:
1334 * @element_class: a #GstElementClass to get pad templates of.
1336 * Retrieves a list of the pad templates associated with @element_class. The
1337 * list must not be modified by the calling code.
1338 * <note>If you use this function in the #GInstanceInitFunc of an object class
1339 * that has subclasses, make sure to pass the g_class parameter of the
1340 * #GInstanceInitFunc here.</note>
1342 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1346 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1348 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1350 return element_class->padtemplates;
1354 * gst_element_class_get_pad_template:
1355 * @element_class: a #GstElementClass to get the pad template of.
1356 * @name: the name of the #GstPadTemplate to get.
1358 * Retrieves a padtemplate from @element_class with the given name.
1359 * <note>If you use this function in the #GInstanceInitFunc of an object class
1360 * that has subclasses, make sure to pass the g_class parameter of the
1361 * #GInstanceInitFunc here.</note>
1363 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1364 * if none was found. No unreferencing is necessary.
1367 gst_element_class_get_pad_template (GstElementClass *
1368 element_class, const gchar * name)
1372 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1373 g_return_val_if_fail (name != NULL, NULL);
1375 padlist = element_class->padtemplates;
1378 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1380 if (strcmp (padtempl->name_template, name) == 0)
1383 padlist = g_list_next (padlist);
1389 static GstPadTemplate *
1390 gst_element_class_get_request_pad_template (GstElementClass *
1391 element_class, const gchar * name)
1393 GstPadTemplate *tmpl;
1395 tmpl = gst_element_class_get_pad_template (element_class, name);
1396 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1402 /* get a random pad on element of the given direction.
1403 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1406 gst_element_get_random_pad (GstElement * element,
1407 gboolean need_linked, GstPadDirection dir)
1409 GstPad *result = NULL;
1412 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1416 GST_OBJECT_LOCK (element);
1417 pads = element->srcpads;
1420 GST_OBJECT_LOCK (element);
1421 pads = element->sinkpads;
1424 goto wrong_direction;
1426 for (; pads; pads = g_list_next (pads)) {
1427 GstPad *pad = GST_PAD_CAST (pads->data);
1429 GST_OBJECT_LOCK (pad);
1430 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1431 GST_DEBUG_PAD_NAME (pad));
1433 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1434 /* if we require a linked pad, and it is not linked, continue the
1436 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1437 GST_DEBUG_PAD_NAME (pad));
1438 GST_OBJECT_UNLOCK (pad);
1441 /* found a pad, stop search */
1442 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1443 GST_DEBUG_PAD_NAME (pad));
1444 GST_OBJECT_UNLOCK (pad);
1450 gst_object_ref (result);
1452 GST_OBJECT_UNLOCK (element);
1456 /* ERROR handling */
1459 g_warning ("unknown pad direction %d", dir);
1465 gst_element_default_send_event (GstElement * element, GstEvent * event)
1467 gboolean result = FALSE;
1470 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1471 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1472 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1475 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1476 "pushing %s event to random %s pad %s:%s",
1477 GST_EVENT_TYPE_NAME (event),
1478 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1479 GST_DEBUG_PAD_NAME (pad));
1481 result = gst_pad_push_event (pad, event);
1482 gst_object_unref (pad);
1484 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1485 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1486 gst_event_unref (event);
1492 * gst_element_send_event:
1493 * @element: a #GstElement to send the event to.
1494 * @event: (transfer full): the #GstEvent to send to the element.
1496 * Sends an event to an element. If the element doesn't implement an
1497 * event handler, the event will be pushed on a random linked sink pad for
1498 * upstream events or a random linked source pad for downstream events.
1500 * This function takes owership of the provided event so you should
1501 * gst_event_ref() it if you want to reuse the event after this call.
1503 * Returns: %TRUE if the event was handled.
1508 gst_element_send_event (GstElement * element, GstEvent * event)
1510 GstElementClass *oclass;
1511 gboolean result = FALSE;
1513 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1514 g_return_val_if_fail (event != NULL, FALSE);
1516 oclass = GST_ELEMENT_GET_CLASS (element);
1518 GST_STATE_LOCK (element);
1519 if (oclass->send_event) {
1520 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1521 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1522 result = oclass->send_event (element, event);
1524 result = gst_element_default_send_event (element, event);
1526 GST_STATE_UNLOCK (element);
1533 * @element: a #GstElement to send the event to.
1534 * @rate: The new playback rate
1535 * @format: The format of the seek values
1536 * @flags: The optional seek flags.
1537 * @cur_type: The type and flags for the new current position
1538 * @cur: The value of the new current position
1539 * @stop_type: The type and flags for the new stop position
1540 * @stop: The value of the new stop position
1542 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1543 * the parameters. The seek event is sent to the element using
1544 * gst_element_send_event().
1546 * Returns: %TRUE if the event was handled.
1551 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1552 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1553 GstSeekType stop_type, gint64 stop)
1558 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1561 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1562 result = gst_element_send_event (element, event);
1568 * gst_element_get_query_types:
1569 * @element: a #GstElement to query
1571 * Get an array of query types from the element.
1572 * If the element doesn't implement a query types function,
1573 * the query will be forwarded to the peer of a random linked sink pad.
1575 * Returns: An array of #GstQueryType elements that should not
1576 * be freed or modified.
1580 const GstQueryType *
1581 gst_element_get_query_types (GstElement * element)
1583 GstElementClass *oclass;
1584 const GstQueryType *result = NULL;
1586 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1588 oclass = GST_ELEMENT_GET_CLASS (element);
1590 if (oclass->get_query_types) {
1591 result = oclass->get_query_types (element);
1593 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1596 GstPad *peer = gst_pad_get_peer (pad);
1599 result = gst_pad_get_query_types (peer);
1601 gst_object_unref (peer);
1603 gst_object_unref (pad);
1610 gst_element_default_query (GstElement * element, GstQuery * query)
1612 gboolean result = FALSE;
1615 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1617 result = gst_pad_query (pad, query);
1619 gst_object_unref (pad);
1621 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1623 GstPad *peer = gst_pad_get_peer (pad);
1626 result = gst_pad_query (peer, query);
1628 gst_object_unref (peer);
1630 gst_object_unref (pad);
1637 * gst_element_query:
1638 * @element: a #GstElement to perform the query on.
1639 * @query: (transfer none): the #GstQuery.
1641 * Performs a query on the given element.
1643 * For elements that don't implement a query handler, this function
1644 * forwards the query to a random srcpad or to the peer of a
1645 * random linked sinkpad of this element.
1647 * Please note that some queries might need a running pipeline to work.
1649 * Returns: TRUE if the query could be performed.
1654 gst_element_query (GstElement * element, GstQuery * query)
1656 GstElementClass *oclass;
1657 gboolean result = FALSE;
1659 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1660 g_return_val_if_fail (query != NULL, FALSE);
1662 oclass = GST_ELEMENT_GET_CLASS (element);
1664 if (oclass->query) {
1665 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1666 GST_ELEMENT_NAME (element));
1667 result = oclass->query (element, query);
1669 result = gst_element_default_query (element, query);
1675 * gst_element_post_message:
1676 * @element: a #GstElement posting the message
1677 * @message: (transfer full): a #GstMessage to post
1679 * Post a message on the element's #GstBus. This function takes ownership of the
1680 * message; if you want to access the message after this call, you should add an
1681 * additional reference before calling.
1683 * Returns: %TRUE if the message was successfully posted. The function returns
1684 * %FALSE if the element did not have a bus.
1689 gst_element_post_message (GstElement * element, GstMessage * message)
1692 gboolean result = FALSE;
1694 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1695 g_return_val_if_fail (message != NULL, FALSE);
1697 GST_OBJECT_LOCK (element);
1700 if (G_UNLIKELY (bus == NULL))
1703 gst_object_ref (bus);
1704 GST_OBJECT_UNLOCK (element);
1706 /* we release the element lock when posting the message so that any
1707 * (synchronous) message handlers can operate on the element */
1708 result = gst_bus_post (bus, message);
1709 gst_object_unref (bus);
1716 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1717 "not posting message %p: no bus", message);
1718 GST_OBJECT_UNLOCK (element);
1719 gst_message_unref (message);
1725 * _gst_element_error_printf:
1726 * @format: the printf-like format to use, or %NULL
1728 * This function is only used internally by the gst_element_error() macro.
1730 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1736 _gst_element_error_printf (const gchar * format, ...)
1746 va_start (args, format);
1747 buffer = g_strdup_vprintf (format, args);
1753 * gst_element_message_full:
1754 * @element: a #GstElement to send message from
1755 * @type: the #GstMessageType
1756 * @domain: the GStreamer GError domain this message belongs to
1757 * @code: the GError code belonging to the domain
1758 * @text: (allow-none) (transfer full): an allocated text string to be used
1759 * as a replacement for the default message connected to code,
1761 * @debug: (allow-none) (transfer full): an allocated debug message to be
1762 * used as a replacement for the default debugging information,
1764 * @file: the source code file where the error was generated
1765 * @function: the source code function where the error was generated
1766 * @line: the source code line where the error was generated
1768 * Post an error, warning or info message on the bus from inside an element.
1770 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1771 * #GST_MESSAGE_INFO.
1775 void gst_element_message_full
1776 (GstElement * element, GstMessageType type,
1777 GQuark domain, gint code, gchar * text,
1778 gchar * debug, const gchar * file, const gchar * function, gint line)
1780 GError *gerror = NULL;
1784 gboolean has_debug = TRUE;
1785 GstMessage *message = NULL;
1788 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1789 g_return_if_fail (GST_IS_ELEMENT (element));
1790 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1791 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1793 /* check if we send the given text or the default error text */
1794 if ((text == NULL) || (text[0] == 0)) {
1795 /* text could have come from g_strdup_printf (""); */
1797 sent_text = gst_error_get_message (domain, code);
1801 /* construct a sent_debug with extra information from source */
1802 if ((debug == NULL) || (debug[0] == 0)) {
1803 /* debug could have come from g_strdup_printf (""); */
1807 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1809 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1810 file, line, function, name, debug);
1812 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1813 file, line, function, name);
1817 /* create gerror and post message */
1818 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1820 gerror = g_error_new_literal (domain, code, sent_text);
1823 case GST_MESSAGE_ERROR:
1825 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1827 case GST_MESSAGE_WARNING:
1828 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1831 case GST_MESSAGE_INFO:
1832 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1836 g_assert_not_reached ();
1839 gst_element_post_message (element, message);
1841 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1842 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1845 g_error_free (gerror);
1846 g_free (sent_debug);
1851 * gst_element_is_locked_state:
1852 * @element: a #GstElement.
1854 * Checks if the state of an element is locked.
1855 * If the state of an element is locked, state changes of the parent don't
1856 * affect the element.
1857 * This way you can leave currently unused elements inside bins. Just lock their
1858 * state before changing the state from #GST_STATE_NULL.
1862 * Returns: TRUE, if the element's state is locked.
1865 gst_element_is_locked_state (GstElement * element)
1869 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1871 GST_OBJECT_LOCK (element);
1872 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1873 GST_OBJECT_UNLOCK (element);
1879 * gst_element_set_locked_state:
1880 * @element: a #GstElement
1881 * @locked_state: TRUE to lock the element's state
1883 * Locks the state of an element, so state changes of the parent don't affect
1884 * this element anymore.
1888 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1889 * or the elements state-locking needed no change.
1892 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1896 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1898 GST_OBJECT_LOCK (element);
1899 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1901 if (G_UNLIKELY (old == locked_state))
1905 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1906 GST_ELEMENT_NAME (element));
1907 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1909 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1910 GST_ELEMENT_NAME (element));
1911 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1913 GST_OBJECT_UNLOCK (element);
1919 GST_CAT_DEBUG (GST_CAT_STATES,
1920 "elements %s was already in locked state %d",
1921 GST_ELEMENT_NAME (element), old);
1922 GST_OBJECT_UNLOCK (element);
1929 * gst_element_sync_state_with_parent:
1930 * @element: a #GstElement.
1932 * Tries to change the state of the element to the same as its parent.
1933 * If this function returns FALSE, the state of element is undefined.
1935 * Returns: TRUE, if the element's state could be synced to the parent's state.
1940 gst_element_sync_state_with_parent (GstElement * element)
1944 GstStateChangeReturn ret;
1946 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1948 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1949 GstState parent_current, parent_pending;
1951 GST_OBJECT_LOCK (parent);
1952 parent_current = GST_STATE (parent);
1953 parent_pending = GST_STATE_PENDING (parent);
1954 GST_OBJECT_UNLOCK (parent);
1956 /* set to pending if there is one, else we set it to the current state of
1958 if (parent_pending != GST_STATE_VOID_PENDING)
1959 target = parent_pending;
1961 target = parent_current;
1963 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1964 "syncing state (%s) to parent %s %s (%s, %s)",
1965 gst_element_state_get_name (GST_STATE (element)),
1966 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1967 gst_element_state_get_name (parent_current),
1968 gst_element_state_get_name (parent_pending));
1970 ret = gst_element_set_state (element, target);
1971 if (ret == GST_STATE_CHANGE_FAILURE)
1974 gst_object_unref (parent);
1978 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1985 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1986 "syncing state failed (%s)",
1987 gst_element_state_change_return_get_name (ret));
1988 gst_object_unref (parent);
1994 static GstStateChangeReturn
1995 gst_element_get_state_func (GstElement * element,
1996 GstState * state, GstState * pending, GstClockTime timeout)
1998 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1999 GstState old_pending;
2001 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2002 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2004 GST_OBJECT_LOCK (element);
2005 ret = GST_STATE_RETURN (element);
2006 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2007 gst_element_state_change_return_get_name (ret));
2009 /* we got an error, report immediately */
2010 if (ret == GST_STATE_CHANGE_FAILURE)
2013 /* we got no_preroll, report immediatly */
2014 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2017 /* no need to wait async if we are not async */
2018 if (ret != GST_STATE_CHANGE_ASYNC)
2021 old_pending = GST_STATE_PENDING (element);
2022 if (old_pending != GST_STATE_VOID_PENDING) {
2023 GTimeVal *timeval, abstimeout;
2026 if (timeout != GST_CLOCK_TIME_NONE) {
2027 glong add = timeout / 1000;
2032 /* make timeout absolute */
2033 g_get_current_time (&abstimeout);
2034 g_time_val_add (&abstimeout, add);
2035 timeval = &abstimeout;
2039 /* get cookie to detect state changes during waiting */
2040 cookie = element->state_cookie;
2042 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2043 "waiting for element to commit state");
2045 /* we have a pending state change, wait for it to complete */
2046 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2047 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2048 /* timeout triggered */
2049 ret = GST_STATE_CHANGE_ASYNC;
2051 if (cookie != element->state_cookie)
2054 /* could be success or failure */
2055 if (old_pending == GST_STATE (element)) {
2056 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2057 ret = GST_STATE_CHANGE_SUCCESS;
2059 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2060 ret = GST_STATE_CHANGE_FAILURE;
2063 /* if nothing is pending anymore we can return SUCCESS */
2064 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2065 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2066 ret = GST_STATE_CHANGE_SUCCESS;
2072 *state = GST_STATE (element);
2074 *pending = GST_STATE_PENDING (element);
2076 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2077 "state current: %s, pending: %s, result: %s",
2078 gst_element_state_get_name (GST_STATE (element)),
2079 gst_element_state_get_name (GST_STATE_PENDING (element)),
2080 gst_element_state_change_return_get_name (ret));
2081 GST_OBJECT_UNLOCK (element);
2088 *state = GST_STATE_VOID_PENDING;
2090 *pending = GST_STATE_VOID_PENDING;
2092 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2094 GST_OBJECT_UNLOCK (element);
2096 return GST_STATE_CHANGE_FAILURE;
2101 * gst_element_get_state:
2102 * @element: a #GstElement to get the state of.
2103 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2105 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2106 * state. Can be %NULL.
2107 * @timeout: a #GstClockTime to specify the timeout for an async
2108 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2110 * Gets the state of the element.
2112 * For elements that performed an ASYNC state change, as reported by
2113 * gst_element_set_state(), this function will block up to the
2114 * specified timeout value for the state change to complete.
2115 * If the element completes the state change or goes into
2116 * an error, this function returns immediately with a return value of
2117 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2119 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2120 * returns the current and pending state immediately.
2122 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2123 * successfully changed its state but is not able to provide data yet.
2124 * This mostly happens for live sources that only produce data in
2125 * %GST_STATE_PLAYING. While the state change return is equivalent to
2126 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2127 * some sink elements might not be able to complete their state change because
2128 * an element is not producing data to complete the preroll. When setting the
2129 * element to playing, the preroll will complete and playback will start.
2131 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2132 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2133 * element is still performing a state change or
2134 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2138 GstStateChangeReturn
2139 gst_element_get_state (GstElement * element,
2140 GstState * state, GstState * pending, GstClockTime timeout)
2142 GstElementClass *oclass;
2143 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2145 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2147 oclass = GST_ELEMENT_GET_CLASS (element);
2149 if (oclass->get_state)
2150 result = (oclass->get_state) (element, state, pending, timeout);
2156 * gst_element_abort_state:
2157 * @element: a #GstElement to abort the state of.
2159 * Abort the state change of the element. This function is used
2160 * by elements that do asynchronous state changes and find out
2161 * something is wrong.
2163 * This function should be called with the STATE_LOCK held.
2168 gst_element_abort_state (GstElement * element)
2172 #ifndef GST_DISABLE_GST_DEBUG
2176 g_return_if_fail (GST_IS_ELEMENT (element));
2178 GST_OBJECT_LOCK (element);
2179 pending = GST_STATE_PENDING (element);
2181 if (pending == GST_STATE_VOID_PENDING ||
2182 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2183 goto nothing_aborted;
2185 #ifndef GST_DISABLE_GST_DEBUG
2186 old_state = GST_STATE (element);
2188 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2189 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2190 gst_element_state_get_name (pending));
2194 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2196 GST_STATE_BROADCAST (element);
2197 GST_OBJECT_UNLOCK (element);
2203 GST_OBJECT_UNLOCK (element);
2208 /* Not static because GstBin has manual state handling too */
2210 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2211 GstState newstate, GstState pending)
2213 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2214 GstMessage *message;
2216 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2217 "notifying about state-changed %s to %s (%s pending)",
2218 gst_element_state_get_name (oldstate),
2219 gst_element_state_get_name (newstate),
2220 gst_element_state_get_name (pending));
2222 if (klass->state_changed)
2223 klass->state_changed (element, oldstate, newstate, pending);
2225 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2226 oldstate, newstate, pending);
2227 gst_element_post_message (element, message);
2231 * gst_element_continue_state:
2232 * @element: a #GstElement to continue the state change of.
2233 * @ret: The previous state return value
2235 * Commit the state change of the element and proceed to the next
2236 * pending state if any. This function is used
2237 * by elements that do asynchronous state changes.
2238 * The core will normally call this method automatically when an
2239 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2241 * If after calling this method the element still has not reached
2242 * the pending state, the next state change is performed.
2244 * This method is used internally and should normally not be called by plugins
2247 * Returns: The result of the commit state change.
2251 GstStateChangeReturn
2252 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2254 GstStateChangeReturn old_ret;
2255 GstState old_state, old_next;
2256 GstState current, next, pending;
2257 GstStateChange transition;
2259 GST_OBJECT_LOCK (element);
2260 old_ret = GST_STATE_RETURN (element);
2261 GST_STATE_RETURN (element) = ret;
2262 pending = GST_STATE_PENDING (element);
2264 /* check if there is something to commit */
2265 if (pending == GST_STATE_VOID_PENDING)
2266 goto nothing_pending;
2268 old_state = GST_STATE (element);
2269 /* this is the state we should go to next */
2270 old_next = GST_STATE_NEXT (element);
2271 /* update current state */
2272 current = GST_STATE (element) = old_next;
2274 /* see if we reached the final state */
2275 if (pending == current)
2278 next = GST_STATE_GET_NEXT (current, pending);
2279 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2281 GST_STATE_NEXT (element) = next;
2283 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2284 GST_OBJECT_UNLOCK (element);
2286 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2287 "committing state from %s to %s, pending %s, next %s",
2288 gst_element_state_get_name (old_state),
2289 gst_element_state_get_name (old_next),
2290 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2292 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2294 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2295 "continue state change %s to %s, final %s",
2296 gst_element_state_get_name (current),
2297 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2299 ret = gst_element_change_state (element, transition);
2305 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2306 GST_OBJECT_UNLOCK (element);
2311 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2312 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2314 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2315 "completed state change to %s", gst_element_state_get_name (pending));
2316 GST_OBJECT_UNLOCK (element);
2318 /* don't post silly messages with the same state. This can happen
2319 * when an element state is changed to what it already was. For bins
2320 * this can be the result of a lost state, which we check with the
2321 * previous return value.
2322 * We do signal the cond though as a _get_state() might be blocking
2324 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2325 _priv_gst_element_state_changed (element, old_state, old_next,
2326 GST_STATE_VOID_PENDING);
2328 GST_STATE_BROADCAST (element);
2335 * gst_element_lost_state:
2336 * @element: a #GstElement the state is lost of
2337 * @new_base_time: if a new base time should be distributed
2339 * Brings the element to the lost state. The current state of the
2340 * element is copied to the pending state so that any call to
2341 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2343 * An ASYNC_START message is posted with indication to distribute a new
2344 * base_time to the element when @new_base_time is %TRUE.
2345 * If the element was PLAYING, it will go to PAUSED. The element
2346 * will be restored to its PLAYING state by the parent pipeline when it
2349 * This is mostly used for elements that lost their preroll buffer
2350 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2351 * they will go to their pending state again when a new preroll buffer is
2352 * queued. This function can only be called when the element is currently
2353 * not in error or an async state change.
2355 * This function is used internally and should normally not be called from
2356 * plugins or applications.
2359 gst_element_lost_state (GstElement * element, gboolean new_base_time)
2361 GstState old_state, new_state;
2362 GstMessage *message;
2364 g_return_if_fail (GST_IS_ELEMENT (element));
2366 GST_OBJECT_LOCK (element);
2367 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2370 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2371 goto only_async_start;
2373 old_state = GST_STATE (element);
2375 /* when we were PLAYING, the new state is PAUSED. We will also not
2376 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2377 * when we preroll. */
2378 if (old_state > GST_STATE_PAUSED)
2379 new_state = GST_STATE_PAUSED;
2381 new_state = old_state;
2383 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2384 "lost state of %s to %s", gst_element_state_get_name (old_state),
2385 gst_element_state_get_name (new_state));
2387 GST_STATE (element) = new_state;
2388 GST_STATE_NEXT (element) = new_state;
2389 GST_STATE_PENDING (element) = new_state;
2390 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2392 GST_ELEMENT_START_TIME (element) = 0;
2393 GST_OBJECT_UNLOCK (element);
2395 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2398 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2399 gst_element_post_message (element, message);
2405 GST_OBJECT_UNLOCK (element);
2410 GST_OBJECT_UNLOCK (element);
2412 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2413 gst_element_post_message (element, message);
2419 * gst_element_set_state:
2420 * @element: a #GstElement to change state of.
2421 * @state: the element's new #GstState.
2423 * Sets the state of the element. This function will try to set the
2424 * requested state by going through all the intermediary states and calling
2425 * the class's state change function for each.
2427 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2428 * element will perform the remainder of the state change asynchronously in
2430 * An application can use gst_element_get_state() to wait for the completion
2431 * of the state change or it can wait for a state change message on the bus.
2433 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2434 * #GST_STATE_CHANGE_ASYNC.
2436 * Returns: Result of the state change using #GstStateChangeReturn.
2440 GstStateChangeReturn
2441 gst_element_set_state (GstElement * element, GstState state)
2443 GstElementClass *oclass;
2444 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2446 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2448 oclass = GST_ELEMENT_GET_CLASS (element);
2450 if (oclass->set_state)
2451 result = (oclass->set_state) (element, state);
2457 * default set state function, calculates the next state based
2458 * on current state and calls the change_state function
2460 static GstStateChangeReturn
2461 gst_element_set_state_func (GstElement * element, GstState state)
2463 GstState current, next, old_pending;
2464 GstStateChangeReturn ret;
2465 GstStateChange transition;
2466 GstStateChangeReturn old_ret;
2468 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2470 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2471 gst_element_state_get_name (state));
2473 /* state lock is taken to protect the set_state() and get_state()
2474 * procedures, it does not lock any variables. */
2475 GST_STATE_LOCK (element);
2477 /* now calculate how to get to the new state */
2478 GST_OBJECT_LOCK (element);
2479 old_ret = GST_STATE_RETURN (element);
2480 /* previous state change returned an error, remove all pending
2481 * and next states */
2482 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2483 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2484 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2485 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2488 current = GST_STATE (element);
2489 next = GST_STATE_NEXT (element);
2490 old_pending = GST_STATE_PENDING (element);
2492 /* this is the (new) state we should go to. TARGET is the last state we set on
2494 if (state != GST_STATE_TARGET (element)) {
2495 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2496 "setting target state to %s", gst_element_state_get_name (state));
2497 GST_STATE_TARGET (element) = state;
2498 /* increment state cookie so that we can track each state change. We only do
2499 * this if this is actually a new state change. */
2500 element->state_cookie++;
2502 GST_STATE_PENDING (element) = state;
2504 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2505 "current %s, old_pending %s, next %s, old return %s",
2506 gst_element_state_get_name (current),
2507 gst_element_state_get_name (old_pending),
2508 gst_element_state_get_name (next),
2509 gst_element_state_change_return_get_name (old_ret));
2511 /* if the element was busy doing a state change, we just update the
2512 * target state, it'll get to it async then. */
2513 if (old_pending != GST_STATE_VOID_PENDING) {
2514 /* upwards state change will happen ASYNC */
2515 if (old_pending <= state)
2517 /* element is going to this state already */
2518 else if (next == state)
2520 /* element was performing an ASYNC upward state change and
2521 * we request to go downward again. Start from the next pending
2523 else if (next > state
2524 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2528 next = GST_STATE_GET_NEXT (current, state);
2529 /* now we store the next state */
2530 GST_STATE_NEXT (element) = next;
2531 /* mark busy, we need to check that there is actually a state change
2532 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2533 * the default element change_state function has no way to know what the
2534 * old value was... could consider this a FIXME...*/
2535 if (current != next)
2536 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2538 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2540 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2541 "%s: setting state from %s to %s",
2542 (next != state ? "intermediate" : "final"),
2543 gst_element_state_get_name (current), gst_element_state_get_name (next));
2545 /* now signal any waiters, they will error since the cookie was incremented */
2546 GST_STATE_BROADCAST (element);
2548 GST_OBJECT_UNLOCK (element);
2550 ret = gst_element_change_state (element, transition);
2552 GST_STATE_UNLOCK (element);
2554 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2555 gst_element_state_change_return_get_name (ret));
2561 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2562 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2563 "element was busy with async state change");
2564 GST_OBJECT_UNLOCK (element);
2566 GST_STATE_UNLOCK (element);
2568 return GST_STATE_CHANGE_ASYNC;
2573 * gst_element_change_state:
2574 * @element: a #GstElement
2575 * @transition: the requested transition
2577 * Perform @transition on @element.
2579 * This function must be called with STATE_LOCK held and is mainly used
2582 * Returns: the #GstStateChangeReturn of the state transition.
2584 GstStateChangeReturn
2585 gst_element_change_state (GstElement * element, GstStateChange transition)
2587 GstElementClass *oclass;
2588 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2590 oclass = GST_ELEMENT_GET_CLASS (element);
2592 /* call the state change function so it can set the state */
2593 if (oclass->change_state)
2594 ret = (oclass->change_state) (element, transition);
2596 ret = GST_STATE_CHANGE_FAILURE;
2599 case GST_STATE_CHANGE_FAILURE:
2600 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2601 "have FAILURE change_state return");
2602 /* state change failure */
2603 gst_element_abort_state (element);
2605 case GST_STATE_CHANGE_ASYNC:
2609 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2610 "element will change state ASYNC");
2612 target = GST_STATE_TARGET (element);
2614 if (target > GST_STATE_READY)
2617 /* else we just continue the state change downwards */
2618 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2619 "forcing commit state %s <= %s",
2620 gst_element_state_get_name (target),
2621 gst_element_state_get_name (GST_STATE_READY));
2623 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2626 case GST_STATE_CHANGE_SUCCESS:
2627 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2628 "element changed state SUCCESS");
2629 /* we can commit the state now which will proceeed to
2631 ret = gst_element_continue_state (element, ret);
2633 case GST_STATE_CHANGE_NO_PREROLL:
2634 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2635 "element changed state NO_PREROLL");
2636 /* we can commit the state now which will proceeed to
2638 ret = gst_element_continue_state (element, ret);
2641 goto invalid_return;
2644 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2649 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2657 GST_OBJECT_LOCK (element);
2658 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2659 g_critical ("%s: unknown return value %d from a state change function",
2660 GST_ELEMENT_NAME (element), ret);
2662 /* we are in error now */
2663 ret = GST_STATE_CHANGE_FAILURE;
2664 GST_STATE_RETURN (element) = ret;
2665 GST_OBJECT_UNLOCK (element);
2671 /* gst_iterator_fold functions for pads_activate
2672 * Stop the iterator if activating one pad failed. */
2674 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2676 GstPad *pad = g_value_get_object (vpad);
2677 gboolean cont = TRUE;
2679 if (!(cont = gst_pad_set_active (pad, *active)))
2680 g_value_set_boolean (ret, FALSE);
2685 /* returns false on error or early cutout of the fold, true if all
2686 * pads in @iter were (de)activated successfully. */
2688 iterator_activate_fold_with_resync (GstIterator * iter,
2689 GstIteratorFoldFunction func, gpointer user_data)
2691 GstIteratorResult ires;
2694 /* no need to unset this later, it's just a boolean */
2695 g_value_init (&ret, G_TYPE_BOOLEAN);
2696 g_value_set_boolean (&ret, TRUE);
2699 ires = gst_iterator_fold (iter, func, &ret, user_data);
2701 case GST_ITERATOR_RESYNC:
2702 /* need to reset the result again */
2703 g_value_set_boolean (&ret, TRUE);
2704 gst_iterator_resync (iter);
2706 case GST_ITERATOR_DONE:
2707 /* all pads iterated, return collected value */
2710 /* iterator returned _ERROR or premature end with _OK,
2711 * mark an error and exit */
2712 g_value_set_boolean (&ret, FALSE);
2717 /* return collected value */
2718 return g_value_get_boolean (&ret);
2721 /* is called with STATE_LOCK
2723 * Pads are activated from source pads to sinkpads.
2726 gst_element_pads_activate (GstElement * element, gboolean active)
2731 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2732 "pads_activate with active %d", active);
2734 iter = gst_element_iterate_src_pads (element);
2736 iterator_activate_fold_with_resync (iter,
2737 (GstIteratorFoldFunction) activate_pads, &active);
2738 gst_iterator_free (iter);
2739 if (G_UNLIKELY (!res))
2742 iter = gst_element_iterate_sink_pads (element);
2744 iterator_activate_fold_with_resync (iter,
2745 (GstIteratorFoldFunction) activate_pads, &active);
2746 gst_iterator_free (iter);
2747 if (G_UNLIKELY (!res))
2750 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2751 "pads_activate successful");
2758 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2759 "source pads_activate failed");
2764 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2765 "sink pads_activate failed");
2770 /* is called with STATE_LOCK */
2771 static GstStateChangeReturn
2772 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2774 GstState state, next;
2775 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2777 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2779 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2780 next = GST_STATE_TRANSITION_NEXT (transition);
2782 /* if the element already is in the given state, we just return success */
2783 if (next == GST_STATE_VOID_PENDING || state == next)
2786 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2787 "default handler tries setting state from %s to %s (%04x)",
2788 gst_element_state_get_name (state),
2789 gst_element_state_get_name (next), transition);
2791 switch (transition) {
2792 case GST_STATE_CHANGE_NULL_TO_READY:
2794 case GST_STATE_CHANGE_READY_TO_PAUSED:
2795 if (!gst_element_pads_activate (element, TRUE)) {
2796 result = GST_STATE_CHANGE_FAILURE;
2799 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2801 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2803 case GST_STATE_CHANGE_PAUSED_TO_READY:
2804 case GST_STATE_CHANGE_READY_TO_NULL:
2805 /* deactivate pads in both cases, since they are activated on
2806 ready->paused but the element might not have made it to paused */
2807 if (!gst_element_pads_activate (element, FALSE)) {
2808 result = GST_STATE_CHANGE_FAILURE;
2812 /* this will catch real but unhandled state changes;
2813 * can only be caused by:
2814 * - a new state was added
2815 * - somehow the element was asked to jump across an intermediate state
2817 g_warning ("Unhandled state change from %s to %s",
2818 gst_element_state_get_name (state),
2819 gst_element_state_get_name (next));
2826 GST_OBJECT_LOCK (element);
2827 result = GST_STATE_RETURN (element);
2828 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2829 "element is already in the %s state",
2830 gst_element_state_get_name (state));
2831 GST_OBJECT_UNLOCK (element);
2838 * gst_element_get_factory:
2839 * @element: a #GstElement to request the element factory of.
2841 * Retrieves the factory that was used to create this element.
2843 * Returns: (transfer none): the #GstElementFactory used for creating this
2844 * element. no refcounting is needed.
2847 gst_element_get_factory (GstElement * element)
2849 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2851 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2855 gst_element_dispose (GObject * object)
2857 GstElement *element = GST_ELEMENT_CAST (object);
2861 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2863 if (GST_STATE (element) != GST_STATE_NULL)
2866 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2867 "removing %d pads", g_list_length (element->pads));
2868 /* first we break all our links with the outside */
2869 while (element->pads && element->pads->data) {
2870 /* don't call _remove_pad with NULL */
2871 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2873 if (G_UNLIKELY (element->pads != NULL)) {
2874 g_critical ("could not remove pads from element %s",
2875 GST_STR_NULL (GST_OBJECT_NAME (object)));
2878 GST_OBJECT_LOCK (element);
2879 clock_p = &element->clock;
2880 bus_p = &element->bus;
2881 gst_object_replace ((GstObject **) clock_p, NULL);
2882 gst_object_replace ((GstObject **) bus_p, NULL);
2883 GST_OBJECT_UNLOCK (element);
2885 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2887 G_OBJECT_CLASS (parent_class)->dispose (object);
2896 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2898 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2900 "You need to explicitly set elements to the NULL state before\n"
2901 "dropping the final reference, to allow them to clean up.\n"
2902 "This problem may also be caused by a refcounting bug in the\n"
2903 "application or some element.\n",
2904 GST_OBJECT_NAME (element),
2905 gst_element_state_get_name (GST_STATE (element)),
2906 is_locked ? " (locked)" : "");
2912 gst_element_finalize (GObject * object)
2914 GstElement *element = GST_ELEMENT_CAST (object);
2916 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2918 GST_STATE_LOCK (element);
2919 if (element->state_cond)
2920 g_cond_free (element->state_cond);
2921 element->state_cond = NULL;
2922 GST_STATE_UNLOCK (element);
2923 g_static_rec_mutex_free (element->state_lock);
2924 g_slice_free (GStaticRecMutex, element->state_lock);
2925 element->state_lock = NULL;
2927 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2929 G_OBJECT_CLASS (parent_class)->finalize (object);
2933 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2937 g_return_if_fail (GST_IS_ELEMENT (element));
2939 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2941 GST_OBJECT_LOCK (element);
2942 bus_p = &GST_ELEMENT_BUS (element);
2943 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2944 GST_OBJECT_UNLOCK (element);
2948 * gst_element_set_bus:
2949 * @element: a #GstElement to set the bus of.
2950 * @bus: (transfer none): the #GstBus to set.
2952 * Sets the bus of the element. Increases the refcount on the bus.
2953 * For internal use only, unless you're testing elements.
2958 gst_element_set_bus (GstElement * element, GstBus * bus)
2960 GstElementClass *oclass;
2962 g_return_if_fail (GST_IS_ELEMENT (element));
2964 oclass = GST_ELEMENT_GET_CLASS (element);
2966 if (oclass->set_bus)
2967 oclass->set_bus (element, bus);
2971 * gst_element_get_bus:
2972 * @element: a #GstElement to get the bus of.
2974 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2975 * bus for the application.
2977 * Returns: (transfer full): the element's #GstBus. unref after usage.
2982 gst_element_get_bus (GstElement * element)
2984 GstBus *result = NULL;
2986 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2988 GST_OBJECT_LOCK (element);
2989 if ((result = GST_ELEMENT_BUS (element)))
2990 gst_object_ref (result);
2991 GST_OBJECT_UNLOCK (element);
2993 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,