2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * All elements have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * A pad of an element can be retrieved by name with gst_element_get_pad().
45 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
47 * Elements can be linked through their pads.
48 * If the link is straightforward, use the gst_element_link()
49 * convenience function to link two elements, or gst_element_link_many()
50 * for more elements in a row.
51 * Use gst_element_link_filtered() to link two elements constrained by
52 * a specified set of #GstCaps.
53 * For finer control, use gst_element_link_pads() and
54 * gst_element_link_pads_filtered() to specify the pads to link on
55 * each element by name.
57 * Each element has a state (see #GstState). You can get and set the state
58 * of an element with gst_element_get_state() and gst_element_set_state().
59 * Setting a state triggers a #GstStateChange. To get a string representation
60 * of a #GstState, use gst_element_state_get_name().
62 * You can get and set a #GstClock on an element using gst_element_get_clock()
63 * and gst_element_set_clock().
64 * Some elements can provide a clock for the pipeline if
65 * gst_element_provides_clock() returns %TRUE. With the
66 * gst_element_provide_clock() method one can retrieve the clock provided by
68 * Not all elements require a clock to operate correctly. If
69 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
70 * element with gst_element_set_clock().
72 * Note that clock slection and distribution is normally handled by the
73 * toplevel #GstPipeline so the clock functions are only to be used in very
74 * specific situations.
76 * Last reviewed on 2009-05-29 (0.10.24)
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstelementmetadata.h"
86 #include "gstenumtypes.h"
88 #include "gstmarshal.h"
94 #include "gst-i18n-lib.h"
96 /* Element signals and args */
112 static void gst_element_class_init (GstElementClass * klass);
113 static void gst_element_init (GstElement * element);
114 static void gst_element_base_class_init (gpointer g_class);
115 static void gst_element_base_class_finalize (gpointer g_class);
117 static void gst_element_dispose (GObject * object);
118 static void gst_element_finalize (GObject * object);
120 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
121 GstStateChange transition);
122 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
123 GstState * state, GstState * pending, GstClockTime timeout);
124 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
126 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
128 static gboolean gst_element_default_send_event (GstElement * element,
130 static gboolean gst_element_default_query (GstElement * element,
133 static GstPadTemplate
134 * gst_element_class_get_request_pad_template (GstElementClass *
135 element_class, const gchar * name);
137 static GstObjectClass *parent_class = NULL;
138 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
140 /* this is used in gstelementfactory.c:gst_element_register() */
141 GQuark _gst_elementclass_factory = 0;
144 gst_element_get_type (void)
146 static volatile gsize gst_element_type = 0;
148 if (g_once_init_enter (&gst_element_type)) {
150 static const GTypeInfo element_info = {
151 sizeof (GstElementClass),
152 gst_element_base_class_init,
153 gst_element_base_class_finalize,
154 (GClassInitFunc) gst_element_class_init,
159 (GInstanceInitFunc) gst_element_init,
163 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
164 &element_info, G_TYPE_FLAG_ABSTRACT);
166 _gst_elementclass_factory =
167 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
168 g_once_init_leave (&gst_element_type, _type);
170 return gst_element_type;
174 gst_element_class_init (GstElementClass * klass)
176 GObjectClass *gobject_class;
177 GstObjectClass *gstobject_class;
179 gobject_class = (GObjectClass *) klass;
180 gstobject_class = (GstObjectClass *) klass;
182 parent_class = g_type_class_peek_parent (klass);
185 * GstElement::pad-added:
186 * @gstelement: the object which received the signal
187 * @new_pad: the pad that has been added
189 * a new #GstPad has been added to the element. Note that this signal will
190 * usually be emitted from the context of the streaming thread. Also keep in
191 * mind that if you add new elements to the pipeline in the signal handler
192 * you will need to set them to the desired target state with
193 * gst_element_set() or gst_element_sync_state_with_parent().
195 gst_element_signals[PAD_ADDED] =
196 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
197 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
198 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
200 * GstElement::pad-removed:
201 * @gstelement: the object which received the signal
202 * @old_pad: the pad that has been removed
204 * a #GstPad has been removed from the element
206 gst_element_signals[PAD_REMOVED] =
207 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
208 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
209 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
211 * GstElement::no-more-pads:
212 * @gstelement: the object which received the signal
214 * This signals that the element will not generate more dynamic pads.
215 * Note that this signal will usually be emitted from the context of
216 * the streaming thread.
218 gst_element_signals[NO_MORE_PADS] =
219 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
220 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
221 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
223 gobject_class->dispose = gst_element_dispose;
224 gobject_class->finalize = gst_element_finalize;
226 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
227 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
228 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
229 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
230 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
231 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
232 klass->numpadtemplates = 0;
234 klass->elementfactory = NULL;
238 gst_element_base_class_init (gpointer g_class)
240 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
242 /* FIXME 0.11: Instead of clearing the
243 * pad template list copy the list and increase the refcount of
244 * the pad templates by one.
246 * This will make it possible to add pad templates and set element
247 * details in the class_init functions and is the real GObject way
249 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
251 element_class->metadata = gst_structure_empty_new ("metadata");
252 element_class->padtemplates = NULL;
254 /* set the factory, see gst_element_register() */
255 element_class->elementfactory =
256 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
257 _gst_elementclass_factory);
258 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
259 element_class->elementfactory);
263 gst_element_base_class_finalize (gpointer g_class)
265 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
267 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
268 g_list_free (klass->padtemplates);
270 gst_structure_free (klass->metadata);
274 gst_element_init (GstElement * element)
276 GST_STATE (element) = GST_STATE_NULL;
277 GST_STATE_TARGET (element) = GST_STATE_NULL;
278 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
279 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
280 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
282 /* FIXME 0.11: Store this directly in the instance struct */
283 element->state_lock = g_slice_new (GStaticRecMutex);
284 g_static_rec_mutex_init (element->state_lock);
285 element->state_cond = g_cond_new ();
289 * gst_element_release_request_pad:
290 * @element: a #GstElement to release the request pad of.
291 * @pad: the #GstPad to release.
293 * Makes the element free the previously requested pad as obtained
294 * with gst_element_get_request_pad().
296 * This does not unref the pad. If the pad was created by using
297 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
298 * followed by gst_object_unref() to free the @pad.
303 gst_element_release_request_pad (GstElement * element, GstPad * pad)
305 GstElementClass *oclass;
307 g_return_if_fail (GST_IS_ELEMENT (element));
308 g_return_if_fail (GST_IS_PAD (pad));
310 oclass = GST_ELEMENT_GET_CLASS (element);
312 /* if the element implements a custom release function we call that, else we
313 * simply remove the pad from the element */
314 if (oclass->release_pad)
315 (oclass->release_pad) (element, pad);
317 gst_element_remove_pad (element, pad);
321 * gst_element_requires_clock:
322 * @element: a #GstElement to query
324 * Query if the element requires a clock.
326 * Returns: %TRUE if the element requires a clock
331 gst_element_requires_clock (GstElement * element)
335 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
337 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
343 * gst_element_provides_clock:
344 * @element: a #GstElement to query
346 * Query if the element provides a clock. A #GstClock provided by an
347 * element can be used as the global #GstClock for the pipeline.
348 * An element that can provide a clock is only required to do so in the PAUSED
349 * state, this means when it is fully negotiated and has allocated the resources
350 * to operate the clock.
352 * Returns: %TRUE if the element provides a clock
357 gst_element_provides_clock (GstElement * element)
361 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
363 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
369 * gst_element_provide_clock:
370 * @element: a #GstElement to query
372 * Get the clock provided by the given element.
373 * <note>An element is only required to provide a clock in the PAUSED
374 * state. Some elements can provide a clock in other states.</note>
376 * Returns: (transfer full): the GstClock provided by the element or %NULL
377 * if no clock could be provided. Unref after usage.
382 gst_element_provide_clock (GstElement * element)
384 GstClock *result = NULL;
385 GstElementClass *oclass;
387 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
389 oclass = GST_ELEMENT_GET_CLASS (element);
391 if (oclass->provide_clock)
392 result = oclass->provide_clock (element);
398 * gst_element_set_clock:
399 * @element: a #GstElement to set the clock for.
400 * @clock: the #GstClock to set for the element.
402 * Sets the clock for the element. This function increases the
403 * refcount on the clock. Any previously set clock on the object
406 * Returns: %TRUE if the element accepted the clock. An element can refuse a
407 * clock when it, for example, is not able to slave its internal clock to the
408 * @clock or when it requires a specific clock to operate.
413 gst_element_set_clock (GstElement * element, GstClock * clock)
415 GstElementClass *oclass;
419 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
420 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
422 oclass = GST_ELEMENT_GET_CLASS (element);
424 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
426 if (oclass->set_clock)
427 res = oclass->set_clock (element, clock);
430 /* only update the clock pointer if the element accepted the clock */
431 GST_OBJECT_LOCK (element);
432 clock_p = &element->clock;
433 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
434 GST_OBJECT_UNLOCK (element);
440 * gst_element_get_clock:
441 * @element: a #GstElement to get the clock of.
443 * Gets the currently configured clock of the element. This is the clock as was
444 * last set with gst_element_set_clock().
446 * Returns: (transfer full): the #GstClock of the element. unref after usage.
451 gst_element_get_clock (GstElement * element)
455 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
457 GST_OBJECT_LOCK (element);
458 if ((result = element->clock))
459 gst_object_ref (result);
460 GST_OBJECT_UNLOCK (element);
466 * gst_element_set_base_time:
467 * @element: a #GstElement.
468 * @time: the base time to set.
470 * Set the base time of an element. See gst_element_get_base_time().
475 gst_element_set_base_time (GstElement * element, GstClockTime time)
479 g_return_if_fail (GST_IS_ELEMENT (element));
481 GST_OBJECT_LOCK (element);
482 old = element->base_time;
483 element->base_time = time;
484 GST_OBJECT_UNLOCK (element);
486 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
487 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
488 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
492 * gst_element_get_base_time:
493 * @element: a #GstElement.
495 * Returns the base time of the element. The base time is the
496 * absolute time of the clock when this element was last put to
497 * PLAYING. Subtracting the base time from the clock time gives
498 * the running time of the element.
500 * Returns: the base time of the element.
505 gst_element_get_base_time (GstElement * element)
509 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
511 GST_OBJECT_LOCK (element);
512 result = element->base_time;
513 GST_OBJECT_UNLOCK (element);
519 * gst_element_set_start_time:
520 * @element: a #GstElement.
521 * @time: the base time to set.
523 * Set the start time of an element. The start time of the element is the
524 * running time of the element when it last went to the PAUSED state. In READY
525 * or after a flushing seek, it is set to 0.
527 * Toplevel elements like #GstPipeline will manage the start_time and
528 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
529 * on such a toplevel element will disable the distribution of the base_time to
530 * the children and can be useful if the application manages the base_time
531 * itself, for example if you want to synchronize capture from multiple
532 * pipelines, and you can also ensure that the pipelines have the same clock.
539 gst_element_set_start_time (GstElement * element, GstClockTime time)
543 g_return_if_fail (GST_IS_ELEMENT (element));
545 GST_OBJECT_LOCK (element);
546 old = GST_ELEMENT_START_TIME (element);
547 GST_ELEMENT_START_TIME (element) = time;
548 GST_OBJECT_UNLOCK (element);
550 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
551 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
552 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
556 * gst_element_get_start_time:
557 * @element: a #GstElement.
559 * Returns the start time of the element. The start time is the
560 * running time of the clock when this element was last put to PAUSED.
562 * Usually the start_time is managed by a toplevel element such as
567 * Returns: the start time of the element.
572 gst_element_get_start_time (GstElement * element)
576 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
578 GST_OBJECT_LOCK (element);
579 result = GST_ELEMENT_START_TIME (element);
580 GST_OBJECT_UNLOCK (element);
586 * gst_element_is_indexable:
587 * @element: a #GstElement.
589 * Queries if the element can be indexed.
591 * Returns: TRUE if the element can be indexed.
596 gst_element_is_indexable (GstElement * element)
600 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
602 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
608 * gst_element_set_index:
609 * @element: a #GstElement.
610 * @index: (transfer none): a #GstIndex.
612 * Set @index on the element. The refcount of the index
613 * will be increased, any previously set index is unreffed.
618 gst_element_set_index (GstElement * element, GstIndex * index)
620 GstElementClass *oclass;
622 g_return_if_fail (GST_IS_ELEMENT (element));
623 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
625 oclass = GST_ELEMENT_GET_CLASS (element);
627 if (oclass->set_index)
628 oclass->set_index (element, index);
632 * gst_element_get_index:
633 * @element: a #GstElement.
635 * Gets the index from the element.
637 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
638 * element. unref after usage.
643 gst_element_get_index (GstElement * element)
645 GstElementClass *oclass;
646 GstIndex *result = NULL;
648 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
650 oclass = GST_ELEMENT_GET_CLASS (element);
652 if (oclass->get_index)
653 result = oclass->get_index (element);
659 * gst_element_add_pad:
660 * @element: a #GstElement to add the pad to.
661 * @pad: (transfer full): the #GstPad to add to the element.
663 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
664 * see gst_object_set_parent() for refcounting information.
666 * Pads are not automatically activated so elements should perform the needed
667 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
668 * state. See gst_pad_set_active() for more information about activating pads.
670 * The pad and the element should be unlocked when calling this function.
672 * This function will emit the #GstElement::pad-added signal on the element.
674 * Returns: %TRUE if the pad could be added. This function can fail when
675 * a pad with the same name already existed or the pad already had another
681 gst_element_add_pad (GstElement * element, GstPad * pad)
686 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
687 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
689 /* locking pad to look at the name */
690 GST_OBJECT_LOCK (pad);
691 pad_name = g_strdup (GST_PAD_NAME (pad));
692 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
693 GST_STR_NULL (pad_name));
694 flushing = GST_PAD_IS_FLUSHING (pad);
695 GST_OBJECT_UNLOCK (pad);
697 /* then check to see if there's already a pad by that name here */
698 GST_OBJECT_LOCK (element);
699 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
702 /* try to set the pad's parent */
703 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
704 GST_OBJECT_CAST (element))))
707 /* check for flushing pads */
708 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
709 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
710 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
711 "use gst_pad_set_active(pad,TRUE) before adding it.",
712 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
714 GST_OBJECT_LOCK (pad);
715 GST_PAD_UNSET_FLUSHING (pad);
716 GST_OBJECT_UNLOCK (pad);
721 /* add it to the list */
722 switch (gst_pad_get_direction (pad)) {
724 element->srcpads = g_list_prepend (element->srcpads, pad);
725 element->numsrcpads++;
728 element->sinkpads = g_list_prepend (element->sinkpads, pad);
729 element->numsinkpads++;
734 element->pads = g_list_prepend (element->pads, pad);
736 element->pads_cookie++;
737 GST_OBJECT_UNLOCK (element);
739 /* emit the PAD_ADDED signal */
740 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
747 g_critical ("Padname %s is not unique in element %s, not adding",
748 pad_name, GST_ELEMENT_NAME (element));
749 GST_OBJECT_UNLOCK (element);
756 ("Pad %s already has parent when trying to add to element %s",
757 pad_name, GST_ELEMENT_NAME (element));
758 GST_OBJECT_UNLOCK (element);
764 GST_OBJECT_LOCK (pad);
766 ("Trying to add pad %s to element %s, but it has no direction",
767 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
768 GST_OBJECT_UNLOCK (pad);
769 GST_OBJECT_UNLOCK (element);
775 * gst_element_remove_pad:
776 * @element: a #GstElement to remove pad from.
777 * @pad: (transfer none): the #GstPad to remove from the element.
779 * Removes @pad from @element. @pad will be destroyed if it has not been
780 * referenced elsewhere using gst_object_unparent().
782 * This function is used by plugin developers and should not be used
783 * by applications. Pads that were dynamically requested from elements
784 * with gst_element_get_request_pad() should be released with the
785 * gst_element_release_request_pad() function instead.
787 * Pads are not automatically deactivated so elements should perform the needed
788 * steps to deactivate the pad in case this pad is removed in the PAUSED or
789 * PLAYING state. See gst_pad_set_active() for more information about
792 * The pad and the element should be unlocked when calling this function.
794 * This function will emit the #GstElement::pad-removed signal on the element.
796 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
797 * pad does not belong to the provided element.
802 gst_element_remove_pad (GstElement * element, GstPad * pad)
806 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
807 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
809 /* locking pad to look at the name and parent */
810 GST_OBJECT_LOCK (pad);
811 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
812 GST_STR_NULL (GST_PAD_NAME (pad)));
814 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
816 GST_OBJECT_UNLOCK (pad);
819 if ((peer = gst_pad_get_peer (pad))) {
820 /* window for MT unsafeness, someone else could unlink here
821 * and then we call unlink with wrong pads. The unlink
822 * function would catch this and safely return failed. */
823 if (GST_PAD_IS_SRC (pad))
824 gst_pad_unlink (pad, peer);
826 gst_pad_unlink (peer, pad);
828 gst_object_unref (peer);
831 GST_OBJECT_LOCK (element);
832 /* remove it from the list */
833 switch (gst_pad_get_direction (pad)) {
835 element->srcpads = g_list_remove (element->srcpads, pad);
836 element->numsrcpads--;
839 element->sinkpads = g_list_remove (element->sinkpads, pad);
840 element->numsinkpads--;
843 g_critical ("Removing pad without direction???");
846 element->pads = g_list_remove (element->pads, pad);
848 element->pads_cookie++;
849 GST_OBJECT_UNLOCK (element);
851 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
852 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
854 gst_object_unparent (GST_OBJECT_CAST (pad));
861 /* FIXME, locking order? */
862 GST_OBJECT_LOCK (element);
863 g_critical ("Padname %s:%s does not belong to element %s when removing",
864 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
865 GST_OBJECT_UNLOCK (element);
866 GST_OBJECT_UNLOCK (pad);
872 * gst_element_no_more_pads:
873 * @element: a #GstElement
875 * Use this function to signal that the element does not expect any more pads
876 * to show up in the current pipeline. This function should be called whenever
877 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
878 * pad templates use this in combination with autopluggers to figure out that
879 * the element is done initializing its pads.
881 * This function emits the #GstElement::no-more-pads signal.
886 gst_element_no_more_pads (GstElement * element)
888 g_return_if_fail (GST_IS_ELEMENT (element));
890 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
894 pad_compare_name (GstPad * pad1, const gchar * name)
898 GST_OBJECT_LOCK (pad1);
899 result = strcmp (GST_PAD_NAME (pad1), name);
900 GST_OBJECT_UNLOCK (pad1);
906 * gst_element_get_static_pad:
907 * @element: a #GstElement to find a static pad of.
908 * @name: the name of the static #GstPad to retrieve.
910 * Retrieves a pad from @element by name. This version only retrieves
911 * already-existing (i.e. 'static') pads.
913 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
919 gst_element_get_static_pad (GstElement * element, const gchar * name)
922 GstPad *result = NULL;
924 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
925 g_return_val_if_fail (name != NULL, NULL);
927 GST_OBJECT_LOCK (element);
929 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
931 result = GST_PAD_CAST (find->data);
932 gst_object_ref (result);
935 if (result == NULL) {
936 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
937 name, GST_ELEMENT_NAME (element));
939 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
940 GST_ELEMENT_NAME (element), name);
942 GST_OBJECT_UNLOCK (element);
948 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
949 const gchar * name, const GstCaps * caps)
951 GstPad *newpad = NULL;
952 GstElementClass *oclass;
954 oclass = GST_ELEMENT_GET_CLASS (element);
956 if (oclass->request_new_pad_full)
957 newpad = (oclass->request_new_pad_full) (element, templ, name, caps);
958 else if (oclass->request_new_pad)
959 newpad = (oclass->request_new_pad) (element, templ, name);
962 gst_object_ref (newpad);
968 * gst_element_get_request_pad:
969 * @element: a #GstElement to find a request pad of.
970 * @name: the name of the request #GstPad to retrieve.
972 * Retrieves a pad from the element by name. This version only retrieves
973 * request pads. The pad should be released with
974 * gst_element_release_request_pad().
976 * This method is slow and will be deprecated in the future. New code should
977 * use gst_element_request_pad() with the requested template.
979 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
980 * Release after usage.
983 gst_element_get_request_pad (GstElement * element, const gchar * name)
985 GstPadTemplate *templ = NULL;
987 const gchar *req_name = NULL;
988 gboolean templ_found = FALSE;
991 gchar *str, *endptr = NULL;
992 GstElementClass *class;
994 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
995 g_return_val_if_fail (name != NULL, NULL);
997 class = GST_ELEMENT_GET_CLASS (element);
999 /* if the name contains a %, we assume it's the complete template name. Get
1000 * the template and try to get a pad */
1001 if (strstr (name, "%")) {
1002 templ = gst_element_class_get_request_pad_template (class, name);
1007 /* there is no % in the name, try to find a matching template */
1008 list = class->padtemplates;
1009 while (!templ_found && list) {
1010 templ = (GstPadTemplate *) list->data;
1011 if (templ->presence == GST_PAD_REQUEST) {
1012 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1013 templ->name_template);
1014 /* see if we find an exact match */
1015 if (strcmp (name, templ->name_template) == 0) {
1020 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1021 and %d, occurring at the end of the name_template, are the only
1023 else if ((str = strchr (templ->name_template, '%'))
1024 && strncmp (templ->name_template, name,
1025 str - templ->name_template) == 0
1026 && strlen (name) > str - templ->name_template) {
1027 data = name + (str - templ->name_template);
1028 if (*(str + 1) == 'd') {
1032 tmp = strtol (data, &endptr, 10);
1033 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1054 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1060 * gst_element_request_pad:
1061 * @element: a #GstElement to find a request pad of.
1062 * @templ: a #GstPadTemplate of which we want a pad of.
1063 * @name: (transfer none) (allow-none): the name of the request #GstPad
1064 * to retrieve. Can be %NULL.
1065 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1066 * request. Can be %NULL.
1068 * Retrieves a request pad from the element according to the provided template.
1070 * If the @caps are specified and the element implements thew new
1071 * request_new_pad_full virtual method, the element will use them to select
1072 * which pad to create.
1074 * The pad should be released with gst_element_release_request_pad().
1076 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1077 * Release after usage.
1082 gst_element_request_pad (GstElement * element,
1083 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1085 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1086 g_return_val_if_fail (templ != NULL, NULL);
1088 return _gst_element_request_pad (element, templ, name, caps);
1092 * gst_element_get_pad:
1093 * @element: a #GstElement.
1094 * @name: the name of the pad to retrieve.
1096 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1097 * first, then gst_element_get_request_pad().
1099 * Deprecated: This function is deprecated as it's unclear if the reference
1100 * to the result pad should be released with gst_object_unref() in case of a static pad
1101 * or gst_element_release_request_pad() in case of a request pad.
1102 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1104 * Returns: (transfer full): the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1105 * depending on the type of the pad.
1107 #ifndef GST_REMOVE_DEPRECATED
1108 #ifdef GST_DISABLE_DEPRECATED
1109 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1112 gst_element_get_pad (GstElement * element, const gchar * name)
1116 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1117 g_return_val_if_fail (name != NULL, NULL);
1119 pad = gst_element_get_static_pad (element, name);
1121 pad = gst_element_get_request_pad (element, name);
1125 #endif /* GST_REMOVE_DEPRECATED */
1127 static GstIteratorItem
1128 iterate_pad (GstIterator * it, GstPad * pad)
1130 gst_object_ref (pad);
1131 return GST_ITERATOR_ITEM_PASS;
1134 static GstIterator *
1135 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1137 GstIterator *result;
1139 GST_OBJECT_LOCK (element);
1140 gst_object_ref (element);
1141 result = gst_iterator_new_list (GST_TYPE_PAD,
1142 GST_OBJECT_GET_LOCK (element),
1143 &element->pads_cookie,
1146 (GstIteratorItemFunction) iterate_pad,
1147 (GstIteratorDisposeFunction) gst_object_unref);
1148 GST_OBJECT_UNLOCK (element);
1154 * gst_element_iterate_pads:
1155 * @element: a #GstElement to iterate pads of.
1157 * Retrieves an iterattor of @element's pads. The iterator should
1158 * be freed after usage.
1160 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1166 gst_element_iterate_pads (GstElement * element)
1168 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1170 return gst_element_iterate_pad_list (element, &element->pads);
1174 * gst_element_iterate_src_pads:
1175 * @element: a #GstElement.
1177 * Retrieves an iterator of @element's source pads.
1179 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1185 gst_element_iterate_src_pads (GstElement * element)
1187 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1189 return gst_element_iterate_pad_list (element, &element->srcpads);
1193 * gst_element_iterate_sink_pads:
1194 * @element: a #GstElement.
1196 * Retrieves an iterator of @element's sink pads.
1198 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1204 gst_element_iterate_sink_pads (GstElement * element)
1206 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1208 return gst_element_iterate_pad_list (element, &element->sinkpads);
1212 * gst_element_class_add_pad_template:
1213 * @klass: the #GstElementClass to add the pad template to.
1214 * @templ: (transfer none): a #GstPadTemplate to add to the element class.
1216 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1217 * functions of classes.
1220 gst_element_class_add_pad_template (GstElementClass * klass,
1221 GstPadTemplate * templ)
1223 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1224 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1226 /* FIXME 0.11: allow replacing the pad templates by
1227 * calling this with the same name as an already existing pad
1228 * template. For this we _must_ _not_ ref the added pad template
1229 * a second time and _must_ document that this function takes
1230 * ownership of the pad template. Otherwise we will leak pad templates
1231 * or the caller unref's the pad template and it disappears */
1232 /* avoid registering pad templates with the same name */
1233 g_return_if_fail (gst_element_class_get_pad_template (klass,
1234 templ->name_template) == NULL);
1236 klass->padtemplates = g_list_append (klass->padtemplates,
1237 gst_object_ref (templ));
1238 klass->numpadtemplates++;
1242 * gst_element_class_add_metadata:
1243 * @klass: class to set metadata for
1244 * @key: the key to set
1245 * @value: the value to set
1247 * Set @key with @value as metadata in @klass.
1250 gst_element_class_add_metadata (GstElementClass * klass,
1251 const gchar * key, const gchar * value)
1253 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1254 g_return_if_fail (key != NULL);
1255 g_return_if_fail (value != NULL);
1257 gst_structure_set ((GstStructure *) klass->metadata,
1258 key, G_TYPE_STRING, value, NULL);
1262 * gst_element_class_set_metadata:
1263 * @klass: class to set metadata for
1264 * @longname: The long English name of the element. E.g. "File Sink"
1265 * @classification: String describing the type of element, as an unordered list
1266 * separated with slashes ('/'). See draft-klass.txt of the design docs
1267 * for more details and common types. E.g: "Sink/File"
1268 * @description: Sentence describing the purpose of the element.
1269 * E.g: "Write stream to a file"
1270 * @author: Name and contact details of the author(s). Use \n to separate
1271 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1273 * Sets the detailed information for a #GstElementClass.
1274 * <note>This function is for use in _base_init functions only.</note>
1277 gst_element_class_set_metadata (GstElementClass * klass,
1278 const gchar * longname, const gchar * classification,
1279 const gchar * description, const gchar * author)
1281 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1283 gst_structure_set ((GstStructure *) klass->metadata,
1284 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1285 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1286 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1287 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1291 * gst_element_class_get_pad_template_list:
1292 * @element_class: a #GstElementClass to get pad templates of.
1294 * Retrieves a list of the pad templates associated with @element_class. The
1295 * list must not be modified by the calling code.
1296 * <note>If you use this function in the #GInstanceInitFunc of an object class
1297 * that has subclasses, make sure to pass the g_class parameter of the
1298 * #GInstanceInitFunc here.</note>
1300 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1304 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1306 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1308 return element_class->padtemplates;
1312 * gst_element_class_get_pad_template:
1313 * @element_class: a #GstElementClass to get the pad template of.
1314 * @name: the name of the #GstPadTemplate to get.
1316 * Retrieves a padtemplate from @element_class with the given name.
1317 * <note>If you use this function in the #GInstanceInitFunc of an object class
1318 * that has subclasses, make sure to pass the g_class parameter of the
1319 * #GInstanceInitFunc here.</note>
1321 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1322 * if none was found. No unreferencing is necessary.
1325 gst_element_class_get_pad_template (GstElementClass * element_class,
1330 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1331 g_return_val_if_fail (name != NULL, NULL);
1333 padlist = element_class->padtemplates;
1336 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1338 if (strcmp (padtempl->name_template, name) == 0)
1341 padlist = g_list_next (padlist);
1347 static GstPadTemplate *
1348 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1351 GstPadTemplate *tmpl;
1353 tmpl = gst_element_class_get_pad_template (element_class, name);
1354 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1360 /* get a random pad on element of the given direction.
1361 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1364 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1365 GstPadDirection dir)
1367 GstPad *result = NULL;
1370 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1374 GST_OBJECT_LOCK (element);
1375 pads = element->srcpads;
1378 GST_OBJECT_LOCK (element);
1379 pads = element->sinkpads;
1382 goto wrong_direction;
1384 for (; pads; pads = g_list_next (pads)) {
1385 GstPad *pad = GST_PAD_CAST (pads->data);
1387 GST_OBJECT_LOCK (pad);
1388 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1389 GST_DEBUG_PAD_NAME (pad));
1391 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1392 /* if we require a linked pad, and it is not linked, continue the
1394 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1395 GST_DEBUG_PAD_NAME (pad));
1396 GST_OBJECT_UNLOCK (pad);
1399 /* found a pad, stop search */
1400 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1401 GST_DEBUG_PAD_NAME (pad));
1402 GST_OBJECT_UNLOCK (pad);
1408 gst_object_ref (result);
1410 GST_OBJECT_UNLOCK (element);
1414 /* ERROR handling */
1417 g_warning ("unknown pad direction %d", dir);
1423 gst_element_default_send_event (GstElement * element, GstEvent * event)
1425 gboolean result = FALSE;
1428 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1429 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1430 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1433 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1434 "pushing %s event to random %s pad %s:%s",
1435 GST_EVENT_TYPE_NAME (event),
1436 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1437 GST_DEBUG_PAD_NAME (pad));
1439 result = gst_pad_push_event (pad, event);
1440 gst_object_unref (pad);
1442 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1443 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1449 * gst_element_send_event:
1450 * @element: a #GstElement to send the event to.
1451 * @event: (transfer full): the #GstEvent to send to the element.
1453 * Sends an event to an element. If the element doesn't implement an
1454 * event handler, the event will be pushed on a random linked sink pad for
1455 * upstream events or a random linked source pad for downstream events.
1457 * This function takes owership of the provided event so you should
1458 * gst_event_ref() it if you want to reuse the event after this call.
1460 * Returns: %TRUE if the event was handled.
1465 gst_element_send_event (GstElement * element, GstEvent * event)
1467 GstElementClass *oclass;
1468 gboolean result = FALSE;
1470 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1471 g_return_val_if_fail (event != NULL, FALSE);
1473 oclass = GST_ELEMENT_GET_CLASS (element);
1475 GST_STATE_LOCK (element);
1476 if (oclass->send_event) {
1477 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1478 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1479 result = oclass->send_event (element, event);
1481 result = gst_element_default_send_event (element, event);
1483 GST_STATE_UNLOCK (element);
1490 * @element: a #GstElement to send the event to.
1491 * @rate: The new playback rate
1492 * @format: The format of the seek values
1493 * @flags: The optional seek flags.
1494 * @cur_type: The type and flags for the new current position
1495 * @cur: The value of the new current position
1496 * @stop_type: The type and flags for the new stop position
1497 * @stop: The value of the new stop position
1499 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1500 * the parameters. The seek event is sent to the element using
1501 * gst_element_send_event().
1503 * Returns: %TRUE if the event was handled.
1508 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1509 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1510 GstSeekType stop_type, gint64 stop)
1515 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1518 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1519 result = gst_element_send_event (element, event);
1525 * gst_element_get_query_types:
1526 * @element: a #GstElement to query
1528 * Get an array of query types from the element.
1529 * If the element doesn't implement a query types function,
1530 * the query will be forwarded to the peer of a random linked sink pad.
1532 * Returns: An array of #GstQueryType elements that should not
1533 * be freed or modified.
1537 const GstQueryType *
1538 gst_element_get_query_types (GstElement * element)
1540 GstElementClass *oclass;
1541 const GstQueryType *result = NULL;
1543 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1545 oclass = GST_ELEMENT_GET_CLASS (element);
1547 if (oclass->get_query_types) {
1548 result = oclass->get_query_types (element);
1550 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1553 GstPad *peer = gst_pad_get_peer (pad);
1556 result = gst_pad_get_query_types (peer);
1558 gst_object_unref (peer);
1560 gst_object_unref (pad);
1567 gst_element_default_query (GstElement * element, GstQuery * query)
1569 gboolean result = FALSE;
1572 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1574 result = gst_pad_query (pad, query);
1576 gst_object_unref (pad);
1578 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1580 GstPad *peer = gst_pad_get_peer (pad);
1583 result = gst_pad_query (peer, query);
1585 gst_object_unref (peer);
1587 gst_object_unref (pad);
1594 * gst_element_query:
1595 * @element: a #GstElement to perform the query on.
1596 * @query: (transfer none): the #GstQuery.
1598 * Performs a query on the given element.
1600 * For elements that don't implement a query handler, this function
1601 * forwards the query to a random srcpad or to the peer of a
1602 * random linked sinkpad of this element.
1604 * Please note that some queries might need a running pipeline to work.
1606 * Returns: TRUE if the query could be performed.
1611 gst_element_query (GstElement * element, GstQuery * query)
1613 GstElementClass *oclass;
1614 gboolean result = FALSE;
1616 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1617 g_return_val_if_fail (query != NULL, FALSE);
1619 oclass = GST_ELEMENT_GET_CLASS (element);
1621 if (oclass->query) {
1622 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1623 GST_ELEMENT_NAME (element));
1624 result = oclass->query (element, query);
1626 result = gst_element_default_query (element, query);
1632 * gst_element_post_message:
1633 * @element: a #GstElement posting the message
1634 * @message: (transfer full): a #GstMessage to post
1636 * Post a message on the element's #GstBus. This function takes ownership of the
1637 * message; if you want to access the message after this call, you should add an
1638 * additional reference before calling.
1640 * Returns: %TRUE if the message was successfully posted. The function returns
1641 * %FALSE if the element did not have a bus.
1646 gst_element_post_message (GstElement * element, GstMessage * message)
1649 gboolean result = FALSE;
1651 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1652 g_return_val_if_fail (message != NULL, FALSE);
1654 GST_OBJECT_LOCK (element);
1657 if (G_UNLIKELY (bus == NULL))
1660 gst_object_ref (bus);
1661 GST_OBJECT_UNLOCK (element);
1663 /* we release the element lock when posting the message so that any
1664 * (synchronous) message handlers can operate on the element */
1665 result = gst_bus_post (bus, message);
1666 gst_object_unref (bus);
1673 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1674 "not posting message %p: no bus", message);
1675 GST_OBJECT_UNLOCK (element);
1676 gst_message_unref (message);
1682 * _gst_element_error_printf:
1683 * @format: the printf-like format to use, or %NULL
1685 * This function is only used internally by the gst_element_error() macro.
1687 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1693 _gst_element_error_printf (const gchar * format, ...)
1703 va_start (args, format);
1704 buffer = g_strdup_vprintf (format, args);
1710 * gst_element_message_full:
1711 * @element: a #GstElement to send message from
1712 * @type: the #GstMessageType
1713 * @domain: the GStreamer GError domain this message belongs to
1714 * @code: the GError code belonging to the domain
1715 * @text: (allow-none) (transfer full): an allocated text string to be used
1716 * as a replacement for the default message connected to code,
1718 * @debug: (allow-none) (transfer full): an allocated debug message to be
1719 * used as a replacement for the default debugging information,
1721 * @file: the source code file where the error was generated
1722 * @function: the source code function where the error was generated
1723 * @line: the source code line where the error was generated
1725 * Post an error, warning or info message on the bus from inside an element.
1727 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1728 * #GST_MESSAGE_INFO.
1732 void gst_element_message_full
1733 (GstElement * element, GstMessageType type,
1734 GQuark domain, gint code, gchar * text,
1735 gchar * debug, const gchar * file, const gchar * function, gint line)
1737 GError *gerror = NULL;
1741 gboolean has_debug = TRUE;
1742 GstMessage *message = NULL;
1745 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1746 g_return_if_fail (GST_IS_ELEMENT (element));
1747 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1748 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1750 /* check if we send the given text or the default error text */
1751 if ((text == NULL) || (text[0] == 0)) {
1752 /* text could have come from g_strdup_printf (""); */
1754 sent_text = gst_error_get_message (domain, code);
1758 /* construct a sent_debug with extra information from source */
1759 if ((debug == NULL) || (debug[0] == 0)) {
1760 /* debug could have come from g_strdup_printf (""); */
1764 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1766 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1767 file, line, function, name, debug);
1769 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1770 file, line, function, name);
1774 /* create gerror and post message */
1775 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1777 gerror = g_error_new_literal (domain, code, sent_text);
1780 case GST_MESSAGE_ERROR:
1782 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1784 case GST_MESSAGE_WARNING:
1785 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1788 case GST_MESSAGE_INFO:
1789 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1793 g_assert_not_reached ();
1796 gst_element_post_message (element, message);
1798 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1799 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1802 g_error_free (gerror);
1803 g_free (sent_debug);
1808 * gst_element_is_locked_state:
1809 * @element: a #GstElement.
1811 * Checks if the state of an element is locked.
1812 * If the state of an element is locked, state changes of the parent don't
1813 * affect the element.
1814 * This way you can leave currently unused elements inside bins. Just lock their
1815 * state before changing the state from #GST_STATE_NULL.
1819 * Returns: TRUE, if the element's state is locked.
1822 gst_element_is_locked_state (GstElement * element)
1826 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1828 GST_OBJECT_LOCK (element);
1829 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1830 GST_OBJECT_UNLOCK (element);
1836 * gst_element_set_locked_state:
1837 * @element: a #GstElement
1838 * @locked_state: TRUE to lock the element's state
1840 * Locks the state of an element, so state changes of the parent don't affect
1841 * this element anymore.
1845 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1846 * or the elements state-locking needed no change.
1849 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1853 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1855 GST_OBJECT_LOCK (element);
1856 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1858 if (G_UNLIKELY (old == locked_state))
1862 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1863 GST_ELEMENT_NAME (element));
1864 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1866 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1867 GST_ELEMENT_NAME (element));
1868 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1870 GST_OBJECT_UNLOCK (element);
1876 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1877 GST_ELEMENT_NAME (element), old);
1878 GST_OBJECT_UNLOCK (element);
1885 * gst_element_sync_state_with_parent:
1886 * @element: a #GstElement.
1888 * Tries to change the state of the element to the same as its parent.
1889 * If this function returns FALSE, the state of element is undefined.
1891 * Returns: TRUE, if the element's state could be synced to the parent's state.
1896 gst_element_sync_state_with_parent (GstElement * element)
1900 GstStateChangeReturn ret;
1902 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1904 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1905 GstState parent_current, parent_pending;
1907 GST_OBJECT_LOCK (parent);
1908 parent_current = GST_STATE (parent);
1909 parent_pending = GST_STATE_PENDING (parent);
1910 GST_OBJECT_UNLOCK (parent);
1912 /* set to pending if there is one, else we set it to the current state of
1914 if (parent_pending != GST_STATE_VOID_PENDING)
1915 target = parent_pending;
1917 target = parent_current;
1919 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1920 "syncing state (%s) to parent %s %s (%s, %s)",
1921 gst_element_state_get_name (GST_STATE (element)),
1922 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1923 gst_element_state_get_name (parent_current),
1924 gst_element_state_get_name (parent_pending));
1926 ret = gst_element_set_state (element, target);
1927 if (ret == GST_STATE_CHANGE_FAILURE)
1930 gst_object_unref (parent);
1934 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1941 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1942 "syncing state failed (%s)",
1943 gst_element_state_change_return_get_name (ret));
1944 gst_object_unref (parent);
1950 static GstStateChangeReturn
1951 gst_element_get_state_func (GstElement * element,
1952 GstState * state, GstState * pending, GstClockTime timeout)
1954 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1955 GstState old_pending;
1957 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1958 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1960 GST_OBJECT_LOCK (element);
1961 ret = GST_STATE_RETURN (element);
1962 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1963 gst_element_state_change_return_get_name (ret));
1965 /* we got an error, report immediately */
1966 if (ret == GST_STATE_CHANGE_FAILURE)
1969 /* we got no_preroll, report immediatly */
1970 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1973 /* no need to wait async if we are not async */
1974 if (ret != GST_STATE_CHANGE_ASYNC)
1977 old_pending = GST_STATE_PENDING (element);
1978 if (old_pending != GST_STATE_VOID_PENDING) {
1979 GTimeVal *timeval, abstimeout;
1982 if (timeout != GST_CLOCK_TIME_NONE) {
1983 glong add = timeout / 1000;
1988 /* make timeout absolute */
1989 g_get_current_time (&abstimeout);
1990 g_time_val_add (&abstimeout, add);
1991 timeval = &abstimeout;
1995 /* get cookie to detect state changes during waiting */
1996 cookie = element->state_cookie;
1998 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1999 "waiting for element to commit state");
2001 /* we have a pending state change, wait for it to complete */
2002 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2003 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2004 /* timeout triggered */
2005 ret = GST_STATE_CHANGE_ASYNC;
2007 if (cookie != element->state_cookie)
2010 /* could be success or failure */
2011 if (old_pending == GST_STATE (element)) {
2012 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2013 ret = GST_STATE_CHANGE_SUCCESS;
2015 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2016 ret = GST_STATE_CHANGE_FAILURE;
2019 /* if nothing is pending anymore we can return SUCCESS */
2020 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2021 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2022 ret = GST_STATE_CHANGE_SUCCESS;
2028 *state = GST_STATE (element);
2030 *pending = GST_STATE_PENDING (element);
2032 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2033 "state current: %s, pending: %s, result: %s",
2034 gst_element_state_get_name (GST_STATE (element)),
2035 gst_element_state_get_name (GST_STATE_PENDING (element)),
2036 gst_element_state_change_return_get_name (ret));
2037 GST_OBJECT_UNLOCK (element);
2044 *state = GST_STATE_VOID_PENDING;
2046 *pending = GST_STATE_VOID_PENDING;
2048 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2050 GST_OBJECT_UNLOCK (element);
2052 return GST_STATE_CHANGE_FAILURE;
2057 * gst_element_get_state:
2058 * @element: a #GstElement to get the state of.
2059 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2061 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2062 * state. Can be %NULL.
2063 * @timeout: a #GstClockTime to specify the timeout for an async
2064 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2066 * Gets the state of the element.
2068 * For elements that performed an ASYNC state change, as reported by
2069 * gst_element_set_state(), this function will block up to the
2070 * specified timeout value for the state change to complete.
2071 * If the element completes the state change or goes into
2072 * an error, this function returns immediately with a return value of
2073 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2075 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2076 * returns the current and pending state immediately.
2078 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2079 * successfully changed its state but is not able to provide data yet.
2080 * This mostly happens for live sources that only produce data in
2081 * %GST_STATE_PLAYING. While the state change return is equivalent to
2082 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2083 * some sink elements might not be able to complete their state change because
2084 * an element is not producing data to complete the preroll. When setting the
2085 * element to playing, the preroll will complete and playback will start.
2087 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2088 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2089 * element is still performing a state change or
2090 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2094 GstStateChangeReturn
2095 gst_element_get_state (GstElement * element,
2096 GstState * state, GstState * pending, GstClockTime timeout)
2098 GstElementClass *oclass;
2099 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2101 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2103 oclass = GST_ELEMENT_GET_CLASS (element);
2105 if (oclass->get_state)
2106 result = (oclass->get_state) (element, state, pending, timeout);
2112 * gst_element_abort_state:
2113 * @element: a #GstElement to abort the state of.
2115 * Abort the state change of the element. This function is used
2116 * by elements that do asynchronous state changes and find out
2117 * something is wrong.
2119 * This function should be called with the STATE_LOCK held.
2124 gst_element_abort_state (GstElement * element)
2128 #ifndef GST_DISABLE_GST_DEBUG
2132 g_return_if_fail (GST_IS_ELEMENT (element));
2134 GST_OBJECT_LOCK (element);
2135 pending = GST_STATE_PENDING (element);
2137 if (pending == GST_STATE_VOID_PENDING ||
2138 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2139 goto nothing_aborted;
2141 #ifndef GST_DISABLE_GST_DEBUG
2142 old_state = GST_STATE (element);
2144 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2145 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2146 gst_element_state_get_name (pending));
2150 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2152 GST_STATE_BROADCAST (element);
2153 GST_OBJECT_UNLOCK (element);
2159 GST_OBJECT_UNLOCK (element);
2165 * gst_element_continue_state:
2166 * @element: a #GstElement to continue the state change of.
2167 * @ret: The previous state return value
2169 * Commit the state change of the element and proceed to the next
2170 * pending state if any. This function is used
2171 * by elements that do asynchronous state changes.
2172 * The core will normally call this method automatically when an
2173 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2175 * If after calling this method the element still has not reached
2176 * the pending state, the next state change is performed.
2178 * This method is used internally and should normally not be called by plugins
2181 * Returns: The result of the commit state change.
2185 GstStateChangeReturn
2186 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2188 GstStateChangeReturn old_ret;
2189 GstState old_state, old_next;
2190 GstState current, next, pending;
2191 GstMessage *message;
2192 GstStateChange transition;
2194 GST_OBJECT_LOCK (element);
2195 old_ret = GST_STATE_RETURN (element);
2196 GST_STATE_RETURN (element) = ret;
2197 pending = GST_STATE_PENDING (element);
2199 /* check if there is something to commit */
2200 if (pending == GST_STATE_VOID_PENDING)
2201 goto nothing_pending;
2203 old_state = GST_STATE (element);
2204 /* this is the state we should go to next */
2205 old_next = GST_STATE_NEXT (element);
2206 /* update current state */
2207 current = GST_STATE (element) = old_next;
2209 /* see if we reached the final state */
2210 if (pending == current)
2213 next = GST_STATE_GET_NEXT (current, pending);
2214 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2216 GST_STATE_NEXT (element) = next;
2218 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2219 GST_OBJECT_UNLOCK (element);
2221 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2222 "committing state from %s to %s, pending %s, next %s",
2223 gst_element_state_get_name (old_state),
2224 gst_element_state_get_name (old_next),
2225 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2227 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2228 old_state, old_next, pending);
2229 gst_element_post_message (element, message);
2231 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2232 "continue state change %s to %s, final %s",
2233 gst_element_state_get_name (current),
2234 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2236 ret = gst_element_change_state (element, transition);
2242 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2243 GST_OBJECT_UNLOCK (element);
2248 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2249 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2251 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2252 "completed state change to %s", gst_element_state_get_name (pending));
2253 GST_OBJECT_UNLOCK (element);
2255 /* don't post silly messages with the same state. This can happen
2256 * when an element state is changed to what it already was. For bins
2257 * this can be the result of a lost state, which we check with the
2258 * previous return value.
2259 * We do signal the cond though as a _get_state() might be blocking
2261 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2262 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2263 "posting state-changed %s to %s",
2264 gst_element_state_get_name (old_state),
2265 gst_element_state_get_name (old_next));
2267 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2268 old_next, GST_STATE_VOID_PENDING);
2269 gst_element_post_message (element, message);
2272 GST_STATE_BROADCAST (element);
2279 * gst_element_lost_state_full:
2280 * @element: a #GstElement the state is lost of
2281 * @new_base_time: if a new base time should be distributed
2283 * Brings the element to the lost state. The current state of the
2284 * element is copied to the pending state so that any call to
2285 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2287 * An ASYNC_START message is posted with indication to distribute a new
2288 * base_time to the element when @new_base_time is %TRUE.
2289 * If the element was PLAYING, it will go to PAUSED. The element
2290 * will be restored to its PLAYING state by the parent pipeline when it
2293 * This is mostly used for elements that lost their preroll buffer
2294 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2295 * they will go to their pending state again when a new preroll buffer is
2296 * queued. This function can only be called when the element is currently
2297 * not in error or an async state change.
2299 * This function is used internally and should normally not be called from
2300 * plugins or applications.
2307 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2309 GstState old_state, new_state;
2310 GstMessage *message;
2312 g_return_if_fail (GST_IS_ELEMENT (element));
2314 GST_OBJECT_LOCK (element);
2315 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2318 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2319 goto only_async_start;
2321 old_state = GST_STATE (element);
2323 /* when we were PLAYING, the new state is PAUSED. We will also not
2324 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2325 * when we preroll. */
2326 if (old_state > GST_STATE_PAUSED)
2327 new_state = GST_STATE_PAUSED;
2329 new_state = old_state;
2331 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2332 "lost state of %s to %s", gst_element_state_get_name (old_state),
2333 gst_element_state_get_name (new_state));
2335 GST_STATE (element) = new_state;
2336 GST_STATE_NEXT (element) = new_state;
2337 GST_STATE_PENDING (element) = new_state;
2338 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2340 GST_ELEMENT_START_TIME (element) = 0;
2341 GST_OBJECT_UNLOCK (element);
2343 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2344 new_state, new_state, new_state);
2345 gst_element_post_message (element, message);
2348 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2349 gst_element_post_message (element, message);
2355 GST_OBJECT_UNLOCK (element);
2360 GST_OBJECT_UNLOCK (element);
2362 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2363 gst_element_post_message (element, message);
2369 * gst_element_lost_state:
2370 * @element: a #GstElement the state is lost of
2372 * Brings the element to the lost state. This function calls
2373 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2375 * This function is used internally and should normally not be called from
2376 * plugins or applications.
2381 gst_element_lost_state (GstElement * element)
2383 gst_element_lost_state_full (element, TRUE);
2387 * gst_element_set_state:
2388 * @element: a #GstElement to change state of.
2389 * @state: the element's new #GstState.
2391 * Sets the state of the element. This function will try to set the
2392 * requested state by going through all the intermediary states and calling
2393 * the class's state change function for each.
2395 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2396 * element will perform the remainder of the state change asynchronously in
2398 * An application can use gst_element_get_state() to wait for the completion
2399 * of the state change or it can wait for a state change message on the bus.
2401 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2402 * #GST_STATE_CHANGE_ASYNC.
2404 * Returns: Result of the state change using #GstStateChangeReturn.
2408 GstStateChangeReturn
2409 gst_element_set_state (GstElement * element, GstState state)
2411 GstElementClass *oclass;
2412 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2414 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2416 oclass = GST_ELEMENT_GET_CLASS (element);
2418 if (oclass->set_state)
2419 result = (oclass->set_state) (element, state);
2425 * default set state function, calculates the next state based
2426 * on current state and calls the change_state function
2428 static GstStateChangeReturn
2429 gst_element_set_state_func (GstElement * element, GstState state)
2431 GstState current, next, old_pending;
2432 GstStateChangeReturn ret;
2433 GstStateChange transition;
2434 GstStateChangeReturn old_ret;
2436 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2438 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2439 gst_element_state_get_name (state));
2441 /* state lock is taken to protect the set_state() and get_state()
2442 * procedures, it does not lock any variables. */
2443 GST_STATE_LOCK (element);
2445 /* now calculate how to get to the new state */
2446 GST_OBJECT_LOCK (element);
2447 old_ret = GST_STATE_RETURN (element);
2448 /* previous state change returned an error, remove all pending
2449 * and next states */
2450 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2451 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2452 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2453 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2456 current = GST_STATE (element);
2457 next = GST_STATE_NEXT (element);
2458 old_pending = GST_STATE_PENDING (element);
2460 /* this is the (new) state we should go to. TARGET is the last state we set on
2462 if (state != GST_STATE_TARGET (element)) {
2463 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2464 "setting target state to %s", gst_element_state_get_name (state));
2465 GST_STATE_TARGET (element) = state;
2466 /* increment state cookie so that we can track each state change. We only do
2467 * this if this is actually a new state change. */
2468 element->state_cookie++;
2470 GST_STATE_PENDING (element) = state;
2472 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2473 "current %s, old_pending %s, next %s, old return %s",
2474 gst_element_state_get_name (current),
2475 gst_element_state_get_name (old_pending),
2476 gst_element_state_get_name (next),
2477 gst_element_state_change_return_get_name (old_ret));
2479 /* if the element was busy doing a state change, we just update the
2480 * target state, it'll get to it async then. */
2481 if (old_pending != GST_STATE_VOID_PENDING) {
2482 /* upwards state change will happen ASYNC */
2483 if (old_pending <= state)
2485 /* element is going to this state already */
2486 else if (next == state)
2488 /* element was performing an ASYNC upward state change and
2489 * we request to go downward again. Start from the next pending
2491 else if (next > state
2492 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2496 next = GST_STATE_GET_NEXT (current, state);
2497 /* now we store the next state */
2498 GST_STATE_NEXT (element) = next;
2499 /* mark busy, we need to check that there is actually a state change
2500 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2501 * the default element change_state function has no way to know what the
2502 * old value was... could consider this a FIXME...*/
2503 if (current != next)
2504 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2506 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2508 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2509 "%s: setting state from %s to %s",
2510 (next != state ? "intermediate" : "final"),
2511 gst_element_state_get_name (current), gst_element_state_get_name (next));
2513 /* now signal any waiters, they will error since the cookie was incremented */
2514 GST_STATE_BROADCAST (element);
2516 GST_OBJECT_UNLOCK (element);
2518 ret = gst_element_change_state (element, transition);
2520 GST_STATE_UNLOCK (element);
2522 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2523 gst_element_state_change_return_get_name (ret));
2529 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2530 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2531 "element was busy with async state change");
2532 GST_OBJECT_UNLOCK (element);
2534 GST_STATE_UNLOCK (element);
2536 return GST_STATE_CHANGE_ASYNC;
2541 * gst_element_change_state:
2542 * @element: a #GstElement
2543 * @transition: the requested transition
2545 * Perform @transition on @element.
2547 * This function must be called with STATE_LOCK held and is mainly used
2550 * Returns: the #GstStateChangeReturn of the state transition.
2552 GstStateChangeReturn
2553 gst_element_change_state (GstElement * element, GstStateChange transition)
2555 GstElementClass *oclass;
2556 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2558 oclass = GST_ELEMENT_GET_CLASS (element);
2560 /* call the state change function so it can set the state */
2561 if (oclass->change_state)
2562 ret = (oclass->change_state) (element, transition);
2564 ret = GST_STATE_CHANGE_FAILURE;
2567 case GST_STATE_CHANGE_FAILURE:
2568 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2569 "have FAILURE change_state return");
2570 /* state change failure */
2571 gst_element_abort_state (element);
2573 case GST_STATE_CHANGE_ASYNC:
2577 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2578 "element will change state ASYNC");
2580 target = GST_STATE_TARGET (element);
2582 if (target > GST_STATE_READY)
2585 /* else we just continue the state change downwards */
2586 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2587 "forcing commit state %s <= %s",
2588 gst_element_state_get_name (target),
2589 gst_element_state_get_name (GST_STATE_READY));
2591 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2594 case GST_STATE_CHANGE_SUCCESS:
2595 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2596 "element changed state SUCCESS");
2597 /* we can commit the state now which will proceeed to
2599 ret = gst_element_continue_state (element, ret);
2601 case GST_STATE_CHANGE_NO_PREROLL:
2602 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2603 "element changed state NO_PREROLL");
2604 /* we can commit the state now which will proceeed to
2606 ret = gst_element_continue_state (element, ret);
2609 goto invalid_return;
2612 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2617 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2625 GST_OBJECT_LOCK (element);
2626 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2627 g_critical ("%s: unknown return value %d from a state change function",
2628 GST_ELEMENT_NAME (element), ret);
2630 /* we are in error now */
2631 ret = GST_STATE_CHANGE_FAILURE;
2632 GST_STATE_RETURN (element) = ret;
2633 GST_OBJECT_UNLOCK (element);
2639 /* gst_iterator_fold functions for pads_activate
2640 * Note how we don't stop the iterator when we fail an activation. This is
2641 * probably a FIXME since when one pad activation fails, we don't want to
2642 * continue our state change. */
2644 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2646 if (!gst_pad_set_active (pad, *active))
2647 g_value_set_boolean (ret, FALSE);
2649 /* unref the object that was reffed for us by _fold */
2650 gst_object_unref (pad);
2654 /* set the caps on the pad to NULL */
2656 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2658 gst_pad_set_caps (pad, NULL);
2659 gst_object_unref (pad);
2663 /* returns false on error or early cutout (will never happen because the fold
2664 * function always returns TRUE, see FIXME above) of the fold, true if all
2665 * pads in @iter were (de)activated successfully. */
2667 iterator_activate_fold_with_resync (GstIterator * iter,
2668 GstIteratorFoldFunction func, gpointer user_data)
2670 GstIteratorResult ires;
2673 /* no need to unset this later, it's just a boolean */
2674 g_value_init (&ret, G_TYPE_BOOLEAN);
2675 g_value_set_boolean (&ret, TRUE);
2678 ires = gst_iterator_fold (iter, func, &ret, user_data);
2680 case GST_ITERATOR_RESYNC:
2681 /* need to reset the result again */
2682 g_value_set_boolean (&ret, TRUE);
2683 gst_iterator_resync (iter);
2685 case GST_ITERATOR_DONE:
2686 /* all pads iterated, return collected value */
2689 /* iterator returned _ERROR or premature end with _OK,
2690 * mark an error and exit */
2691 g_value_set_boolean (&ret, FALSE);
2696 /* return collected value */
2697 return g_value_get_boolean (&ret);
2700 /* is called with STATE_LOCK
2702 * Pads are activated from source pads to sinkpads.
2705 gst_element_pads_activate (GstElement * element, gboolean active)
2710 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2711 "pads_activate with active %d", active);
2713 iter = gst_element_iterate_src_pads (element);
2715 iterator_activate_fold_with_resync (iter,
2716 (GstIteratorFoldFunction) activate_pads, &active);
2717 gst_iterator_free (iter);
2718 if (G_UNLIKELY (!res))
2721 iter = gst_element_iterate_sink_pads (element);
2723 iterator_activate_fold_with_resync (iter,
2724 (GstIteratorFoldFunction) activate_pads, &active);
2725 gst_iterator_free (iter);
2726 if (G_UNLIKELY (!res))
2730 /* clear the caps on all pads, this should never fail */
2731 iter = gst_element_iterate_pads (element);
2733 iterator_activate_fold_with_resync (iter,
2734 (GstIteratorFoldFunction) clear_caps, &active);
2735 gst_iterator_free (iter);
2736 if (G_UNLIKELY (!res))
2740 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2741 "pads_activate successful");
2748 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2749 "source pads_activate failed");
2754 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2755 "sink pads_activate failed");
2760 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2761 "failed to clear caps on pads");
2766 /* is called with STATE_LOCK */
2767 static GstStateChangeReturn
2768 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2770 GstState state, next;
2771 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2774 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2776 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2777 next = GST_STATE_TRANSITION_NEXT (transition);
2779 /* if the element already is in the given state, we just return success */
2780 if (next == GST_STATE_VOID_PENDING || state == next)
2783 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2784 "default handler tries setting state from %s to %s (%04x)",
2785 gst_element_state_get_name (state),
2786 gst_element_state_get_name (next), transition);
2788 switch (transition) {
2789 case GST_STATE_CHANGE_NULL_TO_READY:
2791 case GST_STATE_CHANGE_READY_TO_PAUSED:
2792 if (!gst_element_pads_activate (element, TRUE)) {
2793 result = GST_STATE_CHANGE_FAILURE;
2796 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2798 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2800 case GST_STATE_CHANGE_PAUSED_TO_READY:
2801 case GST_STATE_CHANGE_READY_TO_NULL:
2802 /* deactivate pads in both cases, since they are activated on
2803 ready->paused but the element might not have made it to paused */
2804 if (!gst_element_pads_activate (element, FALSE)) {
2805 result = GST_STATE_CHANGE_FAILURE;
2807 gst_element_set_base_time (element, 0);
2810 /* In null state release the reference to the clock */
2811 GST_OBJECT_LOCK (element);
2812 clock_p = &element->clock;
2813 gst_object_replace ((GstObject **) clock_p, NULL);
2814 GST_OBJECT_UNLOCK (element);
2817 /* this will catch real but unhandled state changes;
2818 * can only be caused by:
2819 * - a new state was added
2820 * - somehow the element was asked to jump across an intermediate state
2822 g_warning ("Unhandled state change from %s to %s",
2823 gst_element_state_get_name (state),
2824 gst_element_state_get_name (next));
2831 GST_OBJECT_LOCK (element);
2832 result = GST_STATE_RETURN (element);
2833 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2834 "element is already in the %s state",
2835 gst_element_state_get_name (state));
2836 GST_OBJECT_UNLOCK (element);
2843 * gst_element_get_factory:
2844 * @element: a #GstElement to request the element factory of.
2846 * Retrieves the factory that was used to create this element.
2848 * Returns: (transfer none): the #GstElementFactory used for creating this
2849 * element. no refcounting is needed.
2852 gst_element_get_factory (GstElement * element)
2854 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2856 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2860 gst_element_dispose (GObject * object)
2862 GstElement *element = GST_ELEMENT_CAST (object);
2866 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2868 if (GST_STATE (element) != GST_STATE_NULL)
2871 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2872 "removing %d pads", g_list_length (element->pads));
2873 /* first we break all our links with the outside */
2874 while (element->pads && element->pads->data) {
2875 /* don't call _remove_pad with NULL */
2876 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2878 if (G_UNLIKELY (element->pads != NULL)) {
2879 g_critical ("could not remove pads from element %s",
2880 GST_STR_NULL (GST_OBJECT_NAME (object)));
2883 GST_OBJECT_LOCK (element);
2884 clock_p = &element->clock;
2885 bus_p = &element->bus;
2886 gst_object_replace ((GstObject **) clock_p, NULL);
2887 gst_object_replace ((GstObject **) bus_p, NULL);
2888 GST_OBJECT_UNLOCK (element);
2890 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2892 G_OBJECT_CLASS (parent_class)->dispose (object);
2901 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2903 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2905 "You need to explicitly set elements to the NULL state before\n"
2906 "dropping the final reference, to allow them to clean up.\n"
2907 "This problem may also be caused by a refcounting bug in the\n"
2908 "application or some element.\n",
2909 GST_OBJECT_NAME (element),
2910 gst_element_state_get_name (GST_STATE (element)),
2911 is_locked ? " (locked)" : "");
2917 gst_element_finalize (GObject * object)
2919 GstElement *element = GST_ELEMENT_CAST (object);
2921 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2923 GST_STATE_LOCK (element);
2924 if (element->state_cond)
2925 g_cond_free (element->state_cond);
2926 element->state_cond = NULL;
2927 GST_STATE_UNLOCK (element);
2928 g_static_rec_mutex_free (element->state_lock);
2929 g_slice_free (GStaticRecMutex, element->state_lock);
2930 element->state_lock = NULL;
2932 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2934 G_OBJECT_CLASS (parent_class)->finalize (object);
2938 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2942 g_return_if_fail (GST_IS_ELEMENT (element));
2944 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2946 GST_OBJECT_LOCK (element);
2947 bus_p = &GST_ELEMENT_BUS (element);
2948 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2949 GST_OBJECT_UNLOCK (element);
2953 * gst_element_set_bus:
2954 * @element: a #GstElement to set the bus of.
2955 * @bus: (transfer none): the #GstBus to set.
2957 * Sets the bus of the element. Increases the refcount on the bus.
2958 * For internal use only, unless you're testing elements.
2963 gst_element_set_bus (GstElement * element, GstBus * bus)
2965 GstElementClass *oclass;
2967 g_return_if_fail (GST_IS_ELEMENT (element));
2969 oclass = GST_ELEMENT_GET_CLASS (element);
2971 if (oclass->set_bus)
2972 oclass->set_bus (element, bus);
2976 * gst_element_get_bus:
2977 * @element: a #GstElement to get the bus of.
2979 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2980 * bus for the application.
2982 * Returns: (transfer full): the element's #GstBus. unref after usage.
2987 gst_element_get_bus (GstElement * element)
2989 GstBus *result = NULL;
2991 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2993 GST_OBJECT_LOCK (element);
2994 if ((result = GST_ELEMENT_BUS (element)))
2995 gst_object_ref (result);
2996 GST_OBJECT_UNLOCK (element);
2998 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,