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 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate or
47 * gst_element_get_request_pad() with the template name such as "src_\%d".
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * gst_element_provides_clock() returns %TRUE. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If
72 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock slection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
79 * Last reviewed on 2009-05-29 (0.10.24)
82 #include "gst_private.h"
85 #include <gobject/gvaluecollector.h>
87 #include "gstelement.h"
88 #include "gstelementmetadata.h"
89 #include "gstenumtypes.h"
91 #include "gstmarshal.h"
97 #include "gst-i18n-lib.h"
98 #include "glib-compat-private.h"
100 /* Element signals and args */
116 static void gst_element_class_init (GstElementClass * klass);
117 static void gst_element_init (GstElement * element);
118 static void gst_element_base_class_init (gpointer g_class);
119 static void gst_element_base_class_finalize (gpointer g_class);
121 static void gst_element_dispose (GObject * object);
122 static void gst_element_finalize (GObject * object);
124 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
125 GstStateChange transition);
126 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
127 GstState * state, GstState * pending, GstClockTime timeout);
128 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
130 static gboolean gst_element_set_clock_func (GstElement * element,
132 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
134 static gboolean gst_element_default_send_event (GstElement * element,
136 static gboolean gst_element_default_query (GstElement * element,
139 static GstPadTemplate
140 * gst_element_class_get_request_pad_template (GstElementClass *
141 element_class, const gchar * name);
143 static GstObjectClass *parent_class = NULL;
144 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
146 /* this is used in gstelementfactory.c:gst_element_register() */
147 GQuark __gst_elementclass_factory = 0;
150 gst_element_get_type (void)
152 static volatile gsize gst_element_type = 0;
154 if (g_once_init_enter (&gst_element_type)) {
156 static const GTypeInfo element_info = {
157 sizeof (GstElementClass),
158 gst_element_base_class_init,
159 gst_element_base_class_finalize,
160 (GClassInitFunc) gst_element_class_init,
165 (GInstanceInitFunc) gst_element_init,
169 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
170 &element_info, G_TYPE_FLAG_ABSTRACT);
172 __gst_elementclass_factory =
173 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
174 g_once_init_leave (&gst_element_type, _type);
176 return gst_element_type;
180 gst_element_class_init (GstElementClass * klass)
182 GObjectClass *gobject_class;
184 gobject_class = (GObjectClass *) klass;
186 parent_class = g_type_class_peek_parent (klass);
189 * GstElement::pad-added:
190 * @gstelement: the object which received the signal
191 * @new_pad: the pad that has been added
193 * a new #GstPad has been added to the element. Note that this signal will
194 * usually be emitted from the context of the streaming thread. Also keep in
195 * mind that if you add new elements to the pipeline in the signal handler
196 * you will need to set them to the desired target state with
197 * gst_element_set_state() or gst_element_sync_state_with_parent().
199 gst_element_signals[PAD_ADDED] =
200 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
201 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
202 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
204 * GstElement::pad-removed:
205 * @gstelement: the object which received the signal
206 * @old_pad: the pad that has been removed
208 * a #GstPad has been removed from the element
210 gst_element_signals[PAD_REMOVED] =
211 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
212 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
213 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
215 * GstElement::no-more-pads:
216 * @gstelement: the object which received the signal
218 * This signals that the element will not generate more dynamic pads.
219 * Note that this signal will usually be emitted from the context of
220 * the streaming thread.
222 gst_element_signals[NO_MORE_PADS] =
223 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
224 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
225 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
227 gobject_class->dispose = gst_element_dispose;
228 gobject_class->finalize = gst_element_finalize;
230 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
231 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
232 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
233 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
234 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
235 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
236 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
237 klass->numpadtemplates = 0;
239 klass->elementfactory = NULL;
243 gst_element_base_class_init (gpointer g_class)
245 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
246 GList *node, *padtemplates;
248 /* Copy the element details here so elements can inherit the
249 * details from their base class and classes only need to set
250 * the details in class_init instead of base_init */
251 element_class->metadata =
252 element_class->metadata ? gst_structure_copy (element_class->metadata) :
253 gst_structure_new_empty ("metadata");
255 /* Copy the pad templates so elements inherit them
256 * from their base class but elements can add pad templates in class_init
257 * instead of base_init.
259 padtemplates = g_list_copy (element_class->padtemplates);
260 for (node = padtemplates; node != NULL; node = node->next) {
261 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
262 gst_object_ref (tmpl);
264 element_class->padtemplates = padtemplates;
266 /* set the factory, see gst_element_register() */
267 element_class->elementfactory =
268 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
269 __gst_elementclass_factory);
270 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
271 element_class->elementfactory);
275 gst_element_base_class_finalize (gpointer g_class)
277 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
279 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
280 g_list_free (klass->padtemplates);
282 gst_structure_free (klass->metadata);
286 gst_element_init (GstElement * element)
288 GST_STATE (element) = GST_STATE_NULL;
289 GST_STATE_TARGET (element) = GST_STATE_NULL;
290 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
291 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
292 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
294 g_rec_mutex_init (&element->state_lock);
295 g_cond_init (&element->state_cond);
299 * gst_element_release_request_pad:
300 * @element: a #GstElement to release the request pad of.
301 * @pad: the #GstPad to release.
303 * Makes the element free the previously requested pad as obtained
304 * with gst_element_get_request_pad().
306 * This does not unref the pad. If the pad was created by using
307 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
308 * followed by gst_object_unref() to free the @pad.
313 gst_element_release_request_pad (GstElement * element, GstPad * pad)
315 GstElementClass *oclass;
317 g_return_if_fail (GST_IS_ELEMENT (element));
318 g_return_if_fail (GST_IS_PAD (pad));
320 oclass = GST_ELEMENT_GET_CLASS (element);
322 /* if the element implements a custom release function we call that, else we
323 * simply remove the pad from the element */
324 if (oclass->release_pad)
325 (oclass->release_pad) (element, pad);
327 gst_element_remove_pad (element, pad);
331 * gst_element_provide_clock:
332 * @element: a #GstElement to query
334 * Get the clock provided by the given element.
335 * <note>An element is only required to provide a clock in the PAUSED
336 * state. Some elements can provide a clock in other states.</note>
338 * Returns: (transfer full): the GstClock provided by the element or %NULL
339 * if no clock could be provided. Unref after usage.
344 gst_element_provide_clock (GstElement * element)
346 GstClock *result = NULL;
347 GstElementClass *oclass;
349 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
351 oclass = GST_ELEMENT_GET_CLASS (element);
353 if (oclass->provide_clock)
354 result = oclass->provide_clock (element);
360 gst_element_set_clock_func (GstElement * element, GstClock * clock)
364 GST_OBJECT_LOCK (element);
365 clock_p = &element->clock;
366 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
367 GST_OBJECT_UNLOCK (element);
373 * gst_element_set_clock:
374 * @element: a #GstElement to set the clock for.
375 * @clock: the #GstClock to set for the element.
377 * Sets the clock for the element. This function increases the
378 * refcount on the clock. Any previously set clock on the object
381 * Returns: %TRUE if the element accepted the clock. An element can refuse a
382 * clock when it, for example, is not able to slave its internal clock to the
383 * @clock or when it requires a specific clock to operate.
388 gst_element_set_clock (GstElement * element, GstClock * clock)
390 GstElementClass *oclass;
391 gboolean res = FALSE;
393 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
394 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
396 oclass = GST_ELEMENT_GET_CLASS (element);
398 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
400 if (oclass->set_clock)
401 res = oclass->set_clock (element, clock);
407 * gst_element_get_clock:
408 * @element: a #GstElement to get the clock of.
410 * Gets the currently configured clock of the element. This is the clock as was
411 * last set with gst_element_set_clock().
413 * Returns: (transfer full): the #GstClock of the element. unref after usage.
418 gst_element_get_clock (GstElement * element)
422 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
424 GST_OBJECT_LOCK (element);
425 if ((result = element->clock))
426 gst_object_ref (result);
427 GST_OBJECT_UNLOCK (element);
433 * gst_element_set_base_time:
434 * @element: a #GstElement.
435 * @time: the base time to set.
437 * Set the base time of an element. See gst_element_get_base_time().
442 gst_element_set_base_time (GstElement * element, GstClockTime time)
446 g_return_if_fail (GST_IS_ELEMENT (element));
448 GST_OBJECT_LOCK (element);
449 old = element->base_time;
450 element->base_time = time;
451 GST_OBJECT_UNLOCK (element);
453 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
454 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
455 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
459 * gst_element_get_base_time:
460 * @element: a #GstElement.
462 * Returns the base time of the element. The base time is the
463 * absolute time of the clock when this element was last put to
464 * PLAYING. Subtracting the base time from the clock time gives
465 * the running time of the element.
467 * Returns: the base time of the element.
472 gst_element_get_base_time (GstElement * element)
476 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
478 GST_OBJECT_LOCK (element);
479 result = element->base_time;
480 GST_OBJECT_UNLOCK (element);
486 * gst_element_set_start_time:
487 * @element: a #GstElement.
488 * @time: the base time to set.
490 * Set the start time of an element. The start time of the element is the
491 * running time of the element when it last went to the PAUSED state. In READY
492 * or after a flushing seek, it is set to 0.
494 * Toplevel elements like #GstPipeline will manage the start_time and
495 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
496 * on such a toplevel element will disable the distribution of the base_time to
497 * the children and can be useful if the application manages the base_time
498 * itself, for example if you want to synchronize capture from multiple
499 * pipelines, and you can also ensure that the pipelines have the same clock.
506 gst_element_set_start_time (GstElement * element, GstClockTime time)
510 g_return_if_fail (GST_IS_ELEMENT (element));
512 GST_OBJECT_LOCK (element);
513 old = GST_ELEMENT_START_TIME (element);
514 GST_ELEMENT_START_TIME (element) = time;
515 GST_OBJECT_UNLOCK (element);
517 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
518 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
519 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
523 * gst_element_get_start_time:
524 * @element: a #GstElement.
526 * Returns the start time of the element. The start time is the
527 * running time of the clock when this element was last put to PAUSED.
529 * Usually the start_time is managed by a toplevel element such as
534 * Returns: the start time of the element.
539 gst_element_get_start_time (GstElement * element)
543 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
545 GST_OBJECT_LOCK (element);
546 result = GST_ELEMENT_START_TIME (element);
547 GST_OBJECT_UNLOCK (element);
554 * gst_element_set_index:
555 * @element: a #GstElement.
556 * @index: (transfer none): a #GstIndex.
558 * Set @index on the element. The refcount of the index
559 * will be increased, any previously set index is unreffed.
564 gst_element_set_index (GstElement * element, GstIndex * index)
566 GstElementClass *oclass;
568 g_return_if_fail (GST_IS_ELEMENT (element));
569 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
571 oclass = GST_ELEMENT_GET_CLASS (element);
573 if (oclass->set_index)
574 oclass->set_index (element, index);
578 * gst_element_get_index:
579 * @element: a #GstElement.
581 * Gets the index from the element.
583 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
584 * element. unref after usage.
589 gst_element_get_index (GstElement * element)
591 GstElementClass *oclass;
592 GstIndex *result = NULL;
594 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
596 oclass = GST_ELEMENT_GET_CLASS (element);
598 if (oclass->get_index)
599 result = oclass->get_index (element);
606 * gst_element_add_pad:
607 * @element: a #GstElement to add the pad to.
608 * @pad: (transfer full): the #GstPad to add to the element.
610 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
611 * see gst_object_set_parent() for refcounting information.
613 * Pads are not automatically activated so elements should perform the needed
614 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
615 * state. See gst_pad_set_active() for more information about activating pads.
617 * The pad and the element should be unlocked when calling this function.
619 * This function will emit the #GstElement::pad-added signal on the element.
621 * Returns: %TRUE if the pad could be added. This function can fail when
622 * a pad with the same name already existed or the pad already had another
628 gst_element_add_pad (GstElement * element, GstPad * pad)
633 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
634 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
636 /* locking pad to look at the name */
637 GST_OBJECT_LOCK (pad);
638 pad_name = g_strdup (GST_PAD_NAME (pad));
639 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
640 GST_STR_NULL (pad_name));
641 flushing = GST_PAD_IS_FLUSHING (pad);
642 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
643 GST_OBJECT_UNLOCK (pad);
645 /* then check to see if there's already a pad by that name here */
646 GST_OBJECT_LOCK (element);
647 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
650 /* try to set the pad's parent */
651 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
652 GST_OBJECT_CAST (element))))
655 /* check for flushing pads */
656 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
657 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
658 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
659 "use gst_pad_set_active(pad,TRUE) before adding it.",
660 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
662 GST_OBJECT_LOCK (pad);
663 GST_PAD_UNSET_FLUSHING (pad);
664 GST_OBJECT_UNLOCK (pad);
669 /* add it to the list */
670 switch (gst_pad_get_direction (pad)) {
672 element->srcpads = g_list_prepend (element->srcpads, pad);
673 element->numsrcpads++;
676 element->sinkpads = g_list_prepend (element->sinkpads, pad);
677 element->numsinkpads++;
682 element->pads = g_list_prepend (element->pads, pad);
684 element->pads_cookie++;
685 GST_OBJECT_UNLOCK (element);
687 /* emit the PAD_ADDED signal */
688 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
695 g_critical ("Padname %s is not unique in element %s, not adding",
696 pad_name, GST_ELEMENT_NAME (element));
697 GST_OBJECT_UNLOCK (element);
704 ("Pad %s already has parent when trying to add to element %s",
705 pad_name, GST_ELEMENT_NAME (element));
706 GST_OBJECT_UNLOCK (element);
712 GST_OBJECT_LOCK (pad);
714 ("Trying to add pad %s to element %s, but it has no direction",
715 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
716 GST_OBJECT_UNLOCK (pad);
717 GST_OBJECT_UNLOCK (element);
723 * gst_element_remove_pad:
724 * @element: a #GstElement to remove pad from.
725 * @pad: (transfer none): the #GstPad to remove from the element.
727 * Removes @pad from @element. @pad will be destroyed if it has not been
728 * referenced elsewhere using gst_object_unparent().
730 * This function is used by plugin developers and should not be used
731 * by applications. Pads that were dynamically requested from elements
732 * with gst_element_get_request_pad() should be released with the
733 * gst_element_release_request_pad() function instead.
735 * Pads are not automatically deactivated so elements should perform the needed
736 * steps to deactivate the pad in case this pad is removed in the PAUSED or
737 * PLAYING state. See gst_pad_set_active() for more information about
740 * The pad and the element should be unlocked when calling this function.
742 * This function will emit the #GstElement::pad-removed signal on the element.
744 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
745 * pad does not belong to the provided element.
750 gst_element_remove_pad (GstElement * element, GstPad * pad)
754 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
755 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
757 /* locking pad to look at the name and parent */
758 GST_OBJECT_LOCK (pad);
759 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
760 GST_STR_NULL (GST_PAD_NAME (pad)));
762 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
764 GST_OBJECT_UNLOCK (pad);
767 if ((peer = gst_pad_get_peer (pad))) {
768 /* window for MT unsafeness, someone else could unlink here
769 * and then we call unlink with wrong pads. The unlink
770 * function would catch this and safely return failed. */
771 if (GST_PAD_IS_SRC (pad))
772 gst_pad_unlink (pad, peer);
774 gst_pad_unlink (peer, pad);
776 gst_object_unref (peer);
779 GST_OBJECT_LOCK (element);
780 /* remove it from the list */
781 switch (gst_pad_get_direction (pad)) {
783 element->srcpads = g_list_remove (element->srcpads, pad);
784 element->numsrcpads--;
787 element->sinkpads = g_list_remove (element->sinkpads, pad);
788 element->numsinkpads--;
791 g_critical ("Removing pad without direction???");
794 element->pads = g_list_remove (element->pads, pad);
796 element->pads_cookie++;
797 GST_OBJECT_UNLOCK (element);
799 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
800 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
802 gst_object_unparent (GST_OBJECT_CAST (pad));
809 /* locking order is element > pad */
810 GST_OBJECT_UNLOCK (pad);
812 GST_OBJECT_LOCK (element);
813 GST_OBJECT_LOCK (pad);
814 g_critical ("Padname %s:%s does not belong to element %s when removing",
815 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
816 GST_OBJECT_UNLOCK (pad);
817 GST_OBJECT_UNLOCK (element);
823 * gst_element_no_more_pads:
824 * @element: a #GstElement
826 * Use this function to signal that the element does not expect any more pads
827 * to show up in the current pipeline. This function should be called whenever
828 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
829 * pad templates use this in combination with autopluggers to figure out that
830 * the element is done initializing its pads.
832 * This function emits the #GstElement::no-more-pads signal.
837 gst_element_no_more_pads (GstElement * element)
839 g_return_if_fail (GST_IS_ELEMENT (element));
841 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
845 pad_compare_name (GstPad * pad1, const gchar * name)
849 GST_OBJECT_LOCK (pad1);
850 result = strcmp (GST_PAD_NAME (pad1), name);
851 GST_OBJECT_UNLOCK (pad1);
857 * gst_element_get_static_pad:
858 * @element: a #GstElement to find a static pad of.
859 * @name: the name of the static #GstPad to retrieve.
861 * Retrieves a pad from @element by name. This version only retrieves
862 * already-existing (i.e. 'static') pads.
864 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
870 gst_element_get_static_pad (GstElement * element, const gchar * name)
873 GstPad *result = NULL;
875 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
876 g_return_val_if_fail (name != NULL, NULL);
878 GST_OBJECT_LOCK (element);
880 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
882 result = GST_PAD_CAST (find->data);
883 gst_object_ref (result);
886 if (result == NULL) {
887 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
888 name, GST_ELEMENT_NAME (element));
890 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
891 GST_ELEMENT_NAME (element), name);
893 GST_OBJECT_UNLOCK (element);
899 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
900 const gchar * name, const GstCaps * caps)
902 GstPad *newpad = NULL;
903 GstElementClass *oclass;
905 oclass = GST_ELEMENT_GET_CLASS (element);
907 #ifndef G_DISABLE_CHECKS
908 /* Some sanity checking here */
912 /* Is this the template name? */
913 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
914 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
916 const gchar *str, *data;
919 /* Otherwise check if it's a valid name for the name template */
920 str = strchr (templ->name_template, '%');
921 g_return_val_if_fail (str != NULL, NULL);
922 g_return_val_if_fail (strncmp (templ->name_template, name,
923 str - templ->name_template) == 0, NULL);
924 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
926 data = name + (str - templ->name_template);
928 /* Can either be %s or %d or %u, do sanity checking for %d */
929 if (*(str + 1) == 'd') {
933 tmp = g_ascii_strtoll (data, &endptr, 10);
934 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
935 && *endptr == '\0', NULL);
936 } else if (*(str + 1) == 'u') {
940 tmp = g_ascii_strtoull (data, &endptr, 10);
941 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
945 pad = gst_element_get_static_pad (element, name);
947 gst_object_unref (pad);
948 /* FIXME 0.11: Change this to g_return_val_if_fail() */
949 g_critical ("Element %s already has a pad named %s, the behaviour of "
950 " gst_element_get_request_pad() for existing pads is undefined!",
951 GST_ELEMENT_NAME (element), name);
956 if (oclass->request_new_pad)
957 newpad = (oclass->request_new_pad) (element, templ, name, caps);
960 gst_object_ref (newpad);
966 * gst_element_get_request_pad:
967 * @element: a #GstElement to find a request pad of.
968 * @name: the name of the request #GstPad to retrieve.
970 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
971 * retrieves request pads. The pad should be released with
972 * gst_element_release_request_pad().
974 * This method is slow and will be deprecated in the future. New code should
975 * use gst_element_request_pad() with the requested template.
977 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
978 * Release after usage.
981 gst_element_get_request_pad (GstElement * element, const gchar * name)
983 GstPadTemplate *templ = NULL;
985 const gchar *req_name = NULL;
986 gboolean templ_found = FALSE;
989 gchar *str, *endptr = NULL;
990 GstElementClass *class;
992 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
993 g_return_val_if_fail (name != NULL, NULL);
995 class = GST_ELEMENT_GET_CLASS (element);
997 /* if the name contains a %, we assume it's the complete template name. Get
998 * the template and try to get a pad */
999 if (strstr (name, "%")) {
1000 templ = gst_element_class_get_request_pad_template (class, name);
1005 /* there is no % in the name, try to find a matching template */
1006 list = class->padtemplates;
1007 while (!templ_found && list) {
1008 templ = (GstPadTemplate *) list->data;
1009 if (templ->presence == GST_PAD_REQUEST) {
1010 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1011 templ->name_template);
1012 /* see if we find an exact match */
1013 if (strcmp (name, templ->name_template) == 0) {
1018 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1019 and %d and %u, occurring at the end of the name_template, are the only
1021 else if ((str = strchr (templ->name_template, '%'))
1022 && strncmp (templ->name_template, name,
1023 str - templ->name_template) == 0
1024 && strlen (name) > str - templ->name_template) {
1025 data = name + (str - templ->name_template);
1026 if (*(str + 1) == 'd') {
1030 tmp = strtol (data, &endptr, 10);
1031 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1037 } else if (*(str + 1) == 'u') {
1041 tmp = strtoul (data, &endptr, 10);
1042 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1062 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1068 * gst_element_request_pad:
1069 * @element: a #GstElement to find a request pad of.
1070 * @templ: a #GstPadTemplate of which we want a pad of.
1071 * @name: (transfer none) (allow-none): the name of the request #GstPad
1072 * to retrieve. Can be %NULL.
1073 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1074 * request. Can be %NULL.
1076 * Retrieves a request pad from the element according to the provided template.
1077 * Pad templates can be looked up using
1078 * gst_element_factory_get_static_pad_templates().
1080 * The pad should be released with gst_element_release_request_pad().
1082 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1083 * Release after usage.
1088 gst_element_request_pad (GstElement * element,
1089 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1091 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1092 g_return_val_if_fail (templ != NULL, NULL);
1094 return _gst_element_request_pad (element, templ, name, caps);
1097 static GstIterator *
1098 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1100 GstIterator *result;
1102 GST_OBJECT_LOCK (element);
1103 result = gst_iterator_new_list (GST_TYPE_PAD,
1104 GST_OBJECT_GET_LOCK (element),
1105 &element->pads_cookie, padlist, (GObject *) element, NULL);
1106 GST_OBJECT_UNLOCK (element);
1112 * gst_element_iterate_pads:
1113 * @element: a #GstElement to iterate pads of.
1115 * Retrieves an iterator of @element's pads. The iterator should
1116 * be freed after usage. Also more specialized iterators exists such as
1117 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1119 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1125 gst_element_iterate_pads (GstElement * element)
1127 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1129 return gst_element_iterate_pad_list (element, &element->pads);
1133 * gst_element_iterate_src_pads:
1134 * @element: a #GstElement.
1136 * Retrieves an iterator of @element's source pads.
1138 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1144 gst_element_iterate_src_pads (GstElement * element)
1146 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1148 return gst_element_iterate_pad_list (element, &element->srcpads);
1152 * gst_element_iterate_sink_pads:
1153 * @element: a #GstElement.
1155 * Retrieves an iterator of @element's sink pads.
1157 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1163 gst_element_iterate_sink_pads (GstElement * element)
1165 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1167 return gst_element_iterate_pad_list (element, &element->sinkpads);
1171 * gst_element_class_add_pad_template:
1172 * @klass: the #GstElementClass to add the pad template to.
1173 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1175 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1176 * functions of classes. If a pad template with the same name as an already
1177 * existing one is added the old one is replaced by the new one.
1181 gst_element_class_add_pad_template (GstElementClass * klass,
1182 GstPadTemplate * templ)
1184 GList *template_list = klass->padtemplates;
1186 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1187 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1189 /* If we already have a pad template with the same name replace the
1191 while (template_list) {
1192 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1194 /* Found pad with the same name, replace and return */
1195 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1196 gst_object_unref (padtempl);
1197 template_list->data = templ;
1200 template_list = g_list_next (template_list);
1203 /* Take ownership of the floating ref */
1204 gst_object_ref_sink (templ);
1206 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1207 klass->numpadtemplates++;
1211 * gst_element_class_add_metadata:
1212 * @klass: class to set metadata for
1213 * @key: the key to set
1214 * @value: the value to set
1216 * Set @key with @value as metadata in @klass.
1219 gst_element_class_add_metadata (GstElementClass * klass,
1220 const gchar * key, const gchar * value)
1222 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1223 g_return_if_fail (key != NULL);
1224 g_return_if_fail (value != NULL);
1226 gst_structure_set ((GstStructure *) klass->metadata,
1227 key, G_TYPE_STRING, value, NULL);
1231 * gst_element_class_set_metadata:
1232 * @klass: class to set metadata for
1233 * @longname: The long English name of the element. E.g. "File Sink"
1234 * @classification: String describing the type of element, as an unordered list
1235 * separated with slashes ('/'). See draft-klass.txt of the design docs
1236 * for more details and common types. E.g: "Sink/File"
1237 * @description: Sentence describing the purpose of the element.
1238 * E.g: "Write stream to a file"
1239 * @author: Name and contact details of the author(s). Use \n to separate
1240 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1242 * Sets the detailed information for a #GstElementClass.
1243 * <note>This function is for use in _class_init functions only.</note>
1246 gst_element_class_set_metadata (GstElementClass * klass,
1247 const gchar * longname, const gchar * classification,
1248 const gchar * description, const gchar * author)
1250 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1252 gst_structure_set ((GstStructure *) klass->metadata,
1253 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1254 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1255 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1256 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1260 * gst_element_class_get_metadata:
1261 * @klass: class to get metadata for
1262 * @key: the key to get
1264 * Get metadata with @key in @klass.
1266 * Returns: the metadata for @key.
1269 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1271 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1272 g_return_val_if_fail (key != NULL, NULL);
1274 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1278 * gst_element_class_get_pad_template_list:
1279 * @element_class: a #GstElementClass to get pad templates of.
1281 * Retrieves a list of the pad templates associated with @element_class. The
1282 * list must not be modified by the calling code.
1283 * <note>If you use this function in the #GInstanceInitFunc of an object class
1284 * that has subclasses, make sure to pass the g_class parameter of the
1285 * #GInstanceInitFunc here.</note>
1287 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1291 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1293 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1295 return element_class->padtemplates;
1299 * gst_element_class_get_pad_template:
1300 * @element_class: a #GstElementClass to get the pad template of.
1301 * @name: the name of the #GstPadTemplate to get.
1303 * Retrieves a padtemplate from @element_class with the given name.
1304 * <note>If you use this function in the #GInstanceInitFunc of an object class
1305 * that has subclasses, make sure to pass the g_class parameter of the
1306 * #GInstanceInitFunc here.</note>
1308 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1309 * if none was found. No unreferencing is necessary.
1312 gst_element_class_get_pad_template (GstElementClass *
1313 element_class, const gchar * name)
1317 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1318 g_return_val_if_fail (name != NULL, NULL);
1320 padlist = element_class->padtemplates;
1323 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1325 if (strcmp (padtempl->name_template, name) == 0)
1328 padlist = g_list_next (padlist);
1334 static GstPadTemplate *
1335 gst_element_class_get_request_pad_template (GstElementClass *
1336 element_class, const gchar * name)
1338 GstPadTemplate *tmpl;
1340 tmpl = gst_element_class_get_pad_template (element_class, name);
1341 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1347 /* get a random pad on element of the given direction.
1348 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1351 gst_element_get_random_pad (GstElement * element,
1352 gboolean need_linked, GstPadDirection dir)
1354 GstPad *result = NULL;
1357 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1361 GST_OBJECT_LOCK (element);
1362 pads = element->srcpads;
1365 GST_OBJECT_LOCK (element);
1366 pads = element->sinkpads;
1369 goto wrong_direction;
1371 for (; pads; pads = g_list_next (pads)) {
1372 GstPad *pad = GST_PAD_CAST (pads->data);
1374 GST_OBJECT_LOCK (pad);
1375 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1376 GST_DEBUG_PAD_NAME (pad));
1378 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1379 /* if we require a linked pad, and it is not linked, continue the
1381 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1382 GST_DEBUG_PAD_NAME (pad));
1383 GST_OBJECT_UNLOCK (pad);
1386 /* found a pad, stop search */
1387 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1388 GST_DEBUG_PAD_NAME (pad));
1389 GST_OBJECT_UNLOCK (pad);
1395 gst_object_ref (result);
1397 GST_OBJECT_UNLOCK (element);
1401 /* ERROR handling */
1404 g_warning ("unknown pad direction %d", dir);
1410 gst_element_default_send_event (GstElement * element, GstEvent * event)
1412 gboolean result = FALSE;
1415 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1416 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1417 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1420 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1421 "pushing %s event to random %s pad %s:%s",
1422 GST_EVENT_TYPE_NAME (event),
1423 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1424 GST_DEBUG_PAD_NAME (pad));
1426 result = gst_pad_push_event (pad, event);
1427 gst_object_unref (pad);
1429 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1430 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1431 gst_event_unref (event);
1437 * gst_element_send_event:
1438 * @element: a #GstElement to send the event to.
1439 * @event: (transfer full): the #GstEvent to send to the element.
1441 * Sends an event to an element. If the element doesn't implement an
1442 * event handler, the event will be pushed on a random linked sink pad for
1443 * upstream events or a random linked source pad for downstream events.
1445 * This function takes owership of the provided event so you should
1446 * gst_event_ref() it if you want to reuse the event after this call.
1448 * Returns: %TRUE if the event was handled.
1453 gst_element_send_event (GstElement * element, GstEvent * event)
1455 GstElementClass *oclass;
1456 gboolean result = FALSE;
1458 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1459 g_return_val_if_fail (event != NULL, FALSE);
1461 oclass = GST_ELEMENT_GET_CLASS (element);
1463 GST_STATE_LOCK (element);
1464 if (oclass->send_event) {
1465 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1466 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1467 result = oclass->send_event (element, event);
1469 GST_STATE_UNLOCK (element);
1476 * @element: a #GstElement to send the event to.
1477 * @rate: The new playback rate
1478 * @format: The format of the seek values
1479 * @flags: The optional seek flags.
1480 * @cur_type: The type and flags for the new current position
1481 * @cur: The value of the new current position
1482 * @stop_type: The type and flags for the new stop position
1483 * @stop: The value of the new stop position
1485 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1486 * the parameters. The seek event is sent to the element using
1487 * gst_element_send_event().
1489 * Returns: %TRUE if the event was handled.
1494 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1495 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1496 GstSeekType stop_type, gint64 stop)
1501 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1504 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1505 result = gst_element_send_event (element, event);
1511 gst_element_default_query (GstElement * element, GstQuery * query)
1513 gboolean result = FALSE;
1516 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1518 result = gst_pad_query (pad, query);
1520 gst_object_unref (pad);
1522 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1524 GstPad *peer = gst_pad_get_peer (pad);
1527 result = gst_pad_query (peer, query);
1529 gst_object_unref (peer);
1531 gst_object_unref (pad);
1538 * gst_element_query:
1539 * @element: a #GstElement to perform the query on.
1540 * @query: (transfer none): the #GstQuery.
1542 * Performs a query on the given element.
1544 * For elements that don't implement a query handler, this function
1545 * forwards the query to a random srcpad or to the peer of a
1546 * random linked sinkpad of this element.
1548 * Please note that some queries might need a running pipeline to work.
1550 * Returns: TRUE if the query could be performed.
1555 gst_element_query (GstElement * element, GstQuery * query)
1557 GstElementClass *oclass;
1558 gboolean result = FALSE;
1560 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1561 g_return_val_if_fail (query != NULL, FALSE);
1563 oclass = GST_ELEMENT_GET_CLASS (element);
1565 if (oclass->query) {
1566 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1567 GST_ELEMENT_NAME (element));
1568 result = oclass->query (element, query);
1574 * gst_element_post_message:
1575 * @element: a #GstElement posting the message
1576 * @message: (transfer full): a #GstMessage to post
1578 * Post a message on the element's #GstBus. This function takes ownership of the
1579 * message; if you want to access the message after this call, you should add an
1580 * additional reference before calling.
1582 * Returns: %TRUE if the message was successfully posted. The function returns
1583 * %FALSE if the element did not have a bus.
1588 gst_element_post_message (GstElement * element, GstMessage * message)
1591 gboolean result = FALSE;
1593 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1594 g_return_val_if_fail (message != NULL, FALSE);
1596 GST_OBJECT_LOCK (element);
1599 if (G_UNLIKELY (bus == NULL))
1602 gst_object_ref (bus);
1603 GST_OBJECT_UNLOCK (element);
1605 /* we release the element lock when posting the message so that any
1606 * (synchronous) message handlers can operate on the element */
1607 result = gst_bus_post (bus, message);
1608 gst_object_unref (bus);
1615 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1616 "not posting message %p: no bus", message);
1617 GST_OBJECT_UNLOCK (element);
1618 gst_message_unref (message);
1624 * _gst_element_error_printf:
1625 * @format: the printf-like format to use, or %NULL
1627 * This function is only used internally by the gst_element_error() macro.
1629 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1635 _gst_element_error_printf (const gchar * format, ...)
1645 va_start (args, format);
1646 buffer = g_strdup_vprintf (format, args);
1652 * gst_element_message_full:
1653 * @element: a #GstElement to send message from
1654 * @type: the #GstMessageType
1655 * @domain: the GStreamer GError domain this message belongs to
1656 * @code: the GError code belonging to the domain
1657 * @text: (allow-none) (transfer full): an allocated text string to be used
1658 * as a replacement for the default message connected to code,
1660 * @debug: (allow-none) (transfer full): an allocated debug message to be
1661 * used as a replacement for the default debugging information,
1663 * @file: the source code file where the error was generated
1664 * @function: the source code function where the error was generated
1665 * @line: the source code line where the error was generated
1667 * Post an error, warning or info message on the bus from inside an element.
1669 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1670 * #GST_MESSAGE_INFO.
1674 void gst_element_message_full
1675 (GstElement * element, GstMessageType type,
1676 GQuark domain, gint code, gchar * text,
1677 gchar * debug, const gchar * file, const gchar * function, gint line)
1679 GError *gerror = NULL;
1683 gboolean has_debug = TRUE;
1684 GstMessage *message = NULL;
1687 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1688 g_return_if_fail (GST_IS_ELEMENT (element));
1689 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1690 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1692 /* check if we send the given text or the default error text */
1693 if ((text == NULL) || (text[0] == 0)) {
1694 /* text could have come from g_strdup_printf (""); */
1696 sent_text = gst_error_get_message (domain, code);
1700 /* construct a sent_debug with extra information from source */
1701 if ((debug == NULL) || (debug[0] == 0)) {
1702 /* debug could have come from g_strdup_printf (""); */
1706 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1708 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1709 file, line, function, name, debug);
1711 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1712 file, line, function, name);
1716 /* create gerror and post message */
1717 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1719 gerror = g_error_new_literal (domain, code, sent_text);
1722 case GST_MESSAGE_ERROR:
1724 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1726 case GST_MESSAGE_WARNING:
1727 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1730 case GST_MESSAGE_INFO:
1731 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1735 g_assert_not_reached ();
1738 gst_element_post_message (element, message);
1740 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1741 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1744 g_error_free (gerror);
1745 g_free (sent_debug);
1750 * gst_element_is_locked_state:
1751 * @element: a #GstElement.
1753 * Checks if the state of an element is locked.
1754 * If the state of an element is locked, state changes of the parent don't
1755 * affect the element.
1756 * This way you can leave currently unused elements inside bins. Just lock their
1757 * state before changing the state from #GST_STATE_NULL.
1761 * Returns: TRUE, if the element's state is locked.
1764 gst_element_is_locked_state (GstElement * element)
1768 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1770 GST_OBJECT_LOCK (element);
1771 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1772 GST_OBJECT_UNLOCK (element);
1778 * gst_element_set_locked_state:
1779 * @element: a #GstElement
1780 * @locked_state: TRUE to lock the element's state
1782 * Locks the state of an element, so state changes of the parent don't affect
1783 * this element anymore.
1787 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1788 * or the elements state-locking needed no change.
1791 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1795 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1797 GST_OBJECT_LOCK (element);
1798 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1800 if (G_UNLIKELY (old == locked_state))
1804 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1805 GST_ELEMENT_NAME (element));
1806 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1808 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1809 GST_ELEMENT_NAME (element));
1810 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1812 GST_OBJECT_UNLOCK (element);
1818 GST_CAT_DEBUG (GST_CAT_STATES,
1819 "elements %s was already in locked state %d",
1820 GST_ELEMENT_NAME (element), old);
1821 GST_OBJECT_UNLOCK (element);
1828 * gst_element_sync_state_with_parent:
1829 * @element: a #GstElement.
1831 * Tries to change the state of the element to the same as its parent.
1832 * If this function returns FALSE, the state of element is undefined.
1834 * Returns: TRUE, if the element's state could be synced to the parent's state.
1839 gst_element_sync_state_with_parent (GstElement * element)
1843 GstStateChangeReturn ret;
1845 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1847 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1848 GstState parent_current, parent_pending;
1850 GST_OBJECT_LOCK (parent);
1851 parent_current = GST_STATE (parent);
1852 parent_pending = GST_STATE_PENDING (parent);
1853 GST_OBJECT_UNLOCK (parent);
1855 /* set to pending if there is one, else we set it to the current state of
1857 if (parent_pending != GST_STATE_VOID_PENDING)
1858 target = parent_pending;
1860 target = parent_current;
1862 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1863 "syncing state (%s) to parent %s %s (%s, %s)",
1864 gst_element_state_get_name (GST_STATE (element)),
1865 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1866 gst_element_state_get_name (parent_current),
1867 gst_element_state_get_name (parent_pending));
1869 ret = gst_element_set_state (element, target);
1870 if (ret == GST_STATE_CHANGE_FAILURE)
1873 gst_object_unref (parent);
1877 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1884 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1885 "syncing state failed (%s)",
1886 gst_element_state_change_return_get_name (ret));
1887 gst_object_unref (parent);
1893 static GstStateChangeReturn
1894 gst_element_get_state_func (GstElement * element,
1895 GstState * state, GstState * pending, GstClockTime timeout)
1897 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1898 GstState old_pending;
1900 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1901 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1903 GST_OBJECT_LOCK (element);
1904 ret = GST_STATE_RETURN (element);
1905 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1906 gst_element_state_change_return_get_name (ret));
1908 /* we got an error, report immediately */
1909 if (ret == GST_STATE_CHANGE_FAILURE)
1912 /* we got no_preroll, report immediately */
1913 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1916 /* no need to wait async if we are not async */
1917 if (ret != GST_STATE_CHANGE_ASYNC)
1920 old_pending = GST_STATE_PENDING (element);
1921 if (old_pending != GST_STATE_VOID_PENDING) {
1925 /* get cookie to detect state changes during waiting */
1926 cookie = element->state_cookie;
1928 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1929 "waiting for element to commit state");
1931 /* we have a pending state change, wait for it to complete */
1932 if (timeout != GST_CLOCK_TIME_NONE) {
1934 /* make timeout absolute */
1935 end_time = g_get_monotonic_time () + (timeout / 1000);
1936 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
1938 GST_STATE_WAIT (element);
1943 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1944 /* timeout triggered */
1945 ret = GST_STATE_CHANGE_ASYNC;
1947 if (cookie != element->state_cookie)
1950 /* could be success or failure */
1951 if (old_pending == GST_STATE (element)) {
1952 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1953 ret = GST_STATE_CHANGE_SUCCESS;
1955 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1956 ret = GST_STATE_CHANGE_FAILURE;
1959 /* if nothing is pending anymore we can return SUCCESS */
1960 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1961 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1962 ret = GST_STATE_CHANGE_SUCCESS;
1968 *state = GST_STATE (element);
1970 *pending = GST_STATE_PENDING (element);
1972 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1973 "state current: %s, pending: %s, result: %s",
1974 gst_element_state_get_name (GST_STATE (element)),
1975 gst_element_state_get_name (GST_STATE_PENDING (element)),
1976 gst_element_state_change_return_get_name (ret));
1977 GST_OBJECT_UNLOCK (element);
1984 *state = GST_STATE_VOID_PENDING;
1986 *pending = GST_STATE_VOID_PENDING;
1988 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
1990 GST_OBJECT_UNLOCK (element);
1992 return GST_STATE_CHANGE_FAILURE;
1997 * gst_element_get_state:
1998 * @element: a #GstElement to get the state of.
1999 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2001 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2002 * state. Can be %NULL.
2003 * @timeout: a #GstClockTime to specify the timeout for an async
2004 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2006 * Gets the state of the element.
2008 * For elements that performed an ASYNC state change, as reported by
2009 * gst_element_set_state(), this function will block up to the
2010 * specified timeout value for the state change to complete.
2011 * If the element completes the state change or goes into
2012 * an error, this function returns immediately with a return value of
2013 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2015 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2016 * returns the current and pending state immediately.
2018 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2019 * successfully changed its state but is not able to provide data yet.
2020 * This mostly happens for live sources that only produce data in
2021 * %GST_STATE_PLAYING. While the state change return is equivalent to
2022 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2023 * some sink elements might not be able to complete their state change because
2024 * an element is not producing data to complete the preroll. When setting the
2025 * element to playing, the preroll will complete and playback will start.
2027 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2028 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2029 * element is still performing a state change or
2030 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2034 GstStateChangeReturn
2035 gst_element_get_state (GstElement * element,
2036 GstState * state, GstState * pending, GstClockTime timeout)
2038 GstElementClass *oclass;
2039 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2041 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2043 oclass = GST_ELEMENT_GET_CLASS (element);
2045 if (oclass->get_state)
2046 result = (oclass->get_state) (element, state, pending, timeout);
2052 * gst_element_abort_state:
2053 * @element: a #GstElement to abort the state of.
2055 * Abort the state change of the element. This function is used
2056 * by elements that do asynchronous state changes and find out
2057 * something is wrong.
2059 * This function should be called with the STATE_LOCK held.
2064 gst_element_abort_state (GstElement * element)
2068 #ifndef GST_DISABLE_GST_DEBUG
2072 g_return_if_fail (GST_IS_ELEMENT (element));
2074 GST_OBJECT_LOCK (element);
2075 pending = GST_STATE_PENDING (element);
2077 if (pending == GST_STATE_VOID_PENDING ||
2078 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2079 goto nothing_aborted;
2081 #ifndef GST_DISABLE_GST_DEBUG
2082 old_state = GST_STATE (element);
2084 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2085 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2086 gst_element_state_get_name (pending));
2090 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2092 GST_STATE_BROADCAST (element);
2093 GST_OBJECT_UNLOCK (element);
2099 GST_OBJECT_UNLOCK (element);
2104 /* Not static because GstBin has manual state handling too */
2106 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2107 GstState newstate, GstState pending)
2109 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2110 GstMessage *message;
2112 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2113 "notifying about state-changed %s to %s (%s pending)",
2114 gst_element_state_get_name (oldstate),
2115 gst_element_state_get_name (newstate),
2116 gst_element_state_get_name (pending));
2118 if (klass->state_changed)
2119 klass->state_changed (element, oldstate, newstate, pending);
2121 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2122 oldstate, newstate, pending);
2123 gst_element_post_message (element, message);
2127 * gst_element_continue_state:
2128 * @element: a #GstElement to continue the state change of.
2129 * @ret: The previous state return value
2131 * Commit the state change of the element and proceed to the next
2132 * pending state if any. This function is used
2133 * by elements that do asynchronous state changes.
2134 * The core will normally call this method automatically when an
2135 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2137 * If after calling this method the element still has not reached
2138 * the pending state, the next state change is performed.
2140 * This method is used internally and should normally not be called by plugins
2143 * Returns: The result of the commit state change.
2147 GstStateChangeReturn
2148 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2150 GstStateChangeReturn old_ret;
2151 GstState old_state, old_next;
2152 GstState current, next, pending;
2153 GstStateChange transition;
2155 GST_OBJECT_LOCK (element);
2156 old_ret = GST_STATE_RETURN (element);
2157 GST_STATE_RETURN (element) = ret;
2158 pending = GST_STATE_PENDING (element);
2160 /* check if there is something to commit */
2161 if (pending == GST_STATE_VOID_PENDING)
2162 goto nothing_pending;
2164 old_state = GST_STATE (element);
2165 /* this is the state we should go to next */
2166 old_next = GST_STATE_NEXT (element);
2167 /* update current state */
2168 current = GST_STATE (element) = old_next;
2170 /* see if we reached the final state */
2171 if (pending == current)
2174 next = GST_STATE_GET_NEXT (current, pending);
2175 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2177 GST_STATE_NEXT (element) = next;
2179 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2180 GST_OBJECT_UNLOCK (element);
2182 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2183 "committing state from %s to %s, pending %s, next %s",
2184 gst_element_state_get_name (old_state),
2185 gst_element_state_get_name (old_next),
2186 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2188 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2190 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2191 "continue state change %s to %s, final %s",
2192 gst_element_state_get_name (current),
2193 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2195 ret = gst_element_change_state (element, transition);
2201 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2202 GST_OBJECT_UNLOCK (element);
2207 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2208 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2210 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2211 "completed state change to %s", gst_element_state_get_name (pending));
2212 GST_OBJECT_UNLOCK (element);
2214 /* don't post silly messages with the same state. This can happen
2215 * when an element state is changed to what it already was. For bins
2216 * this can be the result of a lost state, which we check with the
2217 * previous return value.
2218 * We do signal the cond though as a _get_state() might be blocking
2220 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2221 _priv_gst_element_state_changed (element, old_state, old_next,
2222 GST_STATE_VOID_PENDING);
2224 GST_STATE_BROADCAST (element);
2231 * gst_element_lost_state:
2232 * @element: a #GstElement the state is lost of
2234 * Brings the element to the lost state. The current state of the
2235 * element is copied to the pending state so that any call to
2236 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2238 * An ASYNC_START message is posted. If the element was PLAYING, it will
2239 * go to PAUSED. The element will be restored to its PLAYING state by
2240 * the parent pipeline when it prerolls again.
2242 * This is mostly used for elements that lost their preroll buffer
2243 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2244 * they will go to their pending state again when a new preroll buffer is
2245 * queued. This function can only be called when the element is currently
2246 * not in error or an async state change.
2248 * This function is used internally and should normally not be called from
2249 * plugins or applications.
2252 gst_element_lost_state (GstElement * element)
2254 GstState old_state, new_state;
2255 GstMessage *message;
2257 g_return_if_fail (GST_IS_ELEMENT (element));
2259 GST_OBJECT_LOCK (element);
2260 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2263 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2264 goto only_async_start;
2266 old_state = GST_STATE (element);
2268 /* when we were PLAYING, the new state is PAUSED. We will also not
2269 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2270 * when we preroll. */
2271 if (old_state > GST_STATE_PAUSED)
2272 new_state = GST_STATE_PAUSED;
2274 new_state = old_state;
2276 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2277 "lost state of %s to %s", gst_element_state_get_name (old_state),
2278 gst_element_state_get_name (new_state));
2280 GST_STATE (element) = new_state;
2281 GST_STATE_NEXT (element) = new_state;
2282 GST_STATE_PENDING (element) = new_state;
2283 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2284 GST_OBJECT_UNLOCK (element);
2286 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2288 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2289 gst_element_post_message (element, message);
2295 GST_OBJECT_UNLOCK (element);
2300 GST_OBJECT_UNLOCK (element);
2302 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2303 gst_element_post_message (element, message);
2309 * gst_element_set_state:
2310 * @element: a #GstElement to change state of.
2311 * @state: the element's new #GstState.
2313 * Sets the state of the element. This function will try to set the
2314 * requested state by going through all the intermediary states and calling
2315 * the class's state change function for each.
2317 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2318 * element will perform the remainder of the state change asynchronously in
2320 * An application can use gst_element_get_state() to wait for the completion
2321 * of the state change or it can wait for a state change message on the bus.
2323 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2324 * #GST_STATE_CHANGE_ASYNC.
2326 * Returns: Result of the state change using #GstStateChangeReturn.
2330 GstStateChangeReturn
2331 gst_element_set_state (GstElement * element, GstState state)
2333 GstElementClass *oclass;
2334 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2336 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2338 oclass = GST_ELEMENT_GET_CLASS (element);
2340 if (oclass->set_state)
2341 result = (oclass->set_state) (element, state);
2347 * default set state function, calculates the next state based
2348 * on current state and calls the change_state function
2350 static GstStateChangeReturn
2351 gst_element_set_state_func (GstElement * element, GstState state)
2353 GstState current, next, old_pending;
2354 GstStateChangeReturn ret;
2355 GstStateChange transition;
2356 GstStateChangeReturn old_ret;
2358 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2360 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2361 gst_element_state_get_name (state));
2363 /* state lock is taken to protect the set_state() and get_state()
2364 * procedures, it does not lock any variables. */
2365 GST_STATE_LOCK (element);
2367 /* now calculate how to get to the new state */
2368 GST_OBJECT_LOCK (element);
2369 old_ret = GST_STATE_RETURN (element);
2370 /* previous state change returned an error, remove all pending
2371 * and next states */
2372 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2373 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2374 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2375 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2378 current = GST_STATE (element);
2379 next = GST_STATE_NEXT (element);
2380 old_pending = GST_STATE_PENDING (element);
2382 /* this is the (new) state we should go to. TARGET is the last state we set on
2384 if (state != GST_STATE_TARGET (element)) {
2385 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2386 "setting target state to %s", gst_element_state_get_name (state));
2387 GST_STATE_TARGET (element) = state;
2388 /* increment state cookie so that we can track each state change. We only do
2389 * this if this is actually a new state change. */
2390 element->state_cookie++;
2392 GST_STATE_PENDING (element) = state;
2394 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2395 "current %s, old_pending %s, next %s, old return %s",
2396 gst_element_state_get_name (current),
2397 gst_element_state_get_name (old_pending),
2398 gst_element_state_get_name (next),
2399 gst_element_state_change_return_get_name (old_ret));
2401 /* if the element was busy doing a state change, we just update the
2402 * target state, it'll get to it async then. */
2403 if (old_pending != GST_STATE_VOID_PENDING) {
2404 /* upwards state change will happen ASYNC */
2405 if (old_pending <= state)
2407 /* element is going to this state already */
2408 else if (next == state)
2410 /* element was performing an ASYNC upward state change and
2411 * we request to go downward again. Start from the next pending
2413 else if (next > state
2414 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2418 next = GST_STATE_GET_NEXT (current, state);
2419 /* now we store the next state */
2420 GST_STATE_NEXT (element) = next;
2421 /* mark busy, we need to check that there is actually a state change
2422 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2423 * the default element change_state function has no way to know what the
2424 * old value was... could consider this a FIXME...*/
2425 if (current != next)
2426 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2428 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2430 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2431 "%s: setting state from %s to %s",
2432 (next != state ? "intermediate" : "final"),
2433 gst_element_state_get_name (current), gst_element_state_get_name (next));
2435 /* now signal any waiters, they will error since the cookie was incremented */
2436 GST_STATE_BROADCAST (element);
2438 GST_OBJECT_UNLOCK (element);
2440 ret = gst_element_change_state (element, transition);
2442 GST_STATE_UNLOCK (element);
2444 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2445 gst_element_state_change_return_get_name (ret));
2451 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2452 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2453 "element was busy with async state change");
2454 GST_OBJECT_UNLOCK (element);
2456 GST_STATE_UNLOCK (element);
2458 return GST_STATE_CHANGE_ASYNC;
2463 * gst_element_change_state:
2464 * @element: a #GstElement
2465 * @transition: the requested transition
2467 * Perform @transition on @element.
2469 * This function must be called with STATE_LOCK held and is mainly used
2472 * Returns: the #GstStateChangeReturn of the state transition.
2474 GstStateChangeReturn
2475 gst_element_change_state (GstElement * element, GstStateChange transition)
2477 GstElementClass *oclass;
2478 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2480 oclass = GST_ELEMENT_GET_CLASS (element);
2482 /* call the state change function so it can set the state */
2483 if (oclass->change_state)
2484 ret = (oclass->change_state) (element, transition);
2486 ret = GST_STATE_CHANGE_FAILURE;
2489 case GST_STATE_CHANGE_FAILURE:
2490 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2491 "have FAILURE change_state return");
2492 /* state change failure */
2493 gst_element_abort_state (element);
2495 case GST_STATE_CHANGE_ASYNC:
2499 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2500 "element will change state ASYNC");
2502 target = GST_STATE_TARGET (element);
2504 if (target > GST_STATE_READY)
2507 /* else we just continue the state change downwards */
2508 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2509 "forcing commit state %s <= %s",
2510 gst_element_state_get_name (target),
2511 gst_element_state_get_name (GST_STATE_READY));
2513 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2516 case GST_STATE_CHANGE_SUCCESS:
2517 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2518 "element changed state SUCCESS");
2519 /* we can commit the state now which will proceeed to
2521 ret = gst_element_continue_state (element, ret);
2523 case GST_STATE_CHANGE_NO_PREROLL:
2524 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2525 "element changed state NO_PREROLL");
2526 /* we can commit the state now which will proceeed to
2528 ret = gst_element_continue_state (element, ret);
2531 goto invalid_return;
2534 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2539 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2547 GST_OBJECT_LOCK (element);
2548 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2549 g_critical ("%s: unknown return value %d from a state change function",
2550 GST_ELEMENT_NAME (element), ret);
2552 /* we are in error now */
2553 ret = GST_STATE_CHANGE_FAILURE;
2554 GST_STATE_RETURN (element) = ret;
2555 GST_OBJECT_UNLOCK (element);
2561 /* gst_iterator_fold functions for pads_activate
2562 * Stop the iterator if activating one pad failed. */
2564 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2566 GstPad *pad = g_value_get_object (vpad);
2567 gboolean cont = TRUE;
2569 if (!(cont = gst_pad_set_active (pad, *active)))
2570 g_value_set_boolean (ret, FALSE);
2575 /* returns false on error or early cutout of the fold, true if all
2576 * pads in @iter were (de)activated successfully. */
2578 iterator_activate_fold_with_resync (GstIterator * iter,
2579 GstIteratorFoldFunction func, gpointer user_data)
2581 GstIteratorResult ires;
2584 /* no need to unset this later, it's just a boolean */
2585 g_value_init (&ret, G_TYPE_BOOLEAN);
2586 g_value_set_boolean (&ret, TRUE);
2589 ires = gst_iterator_fold (iter, func, &ret, user_data);
2591 case GST_ITERATOR_RESYNC:
2592 /* need to reset the result again */
2593 g_value_set_boolean (&ret, TRUE);
2594 gst_iterator_resync (iter);
2596 case GST_ITERATOR_DONE:
2597 /* all pads iterated, return collected value */
2600 /* iterator returned _ERROR or premature end with _OK,
2601 * mark an error and exit */
2602 g_value_set_boolean (&ret, FALSE);
2607 /* return collected value */
2608 return g_value_get_boolean (&ret);
2611 /* is called with STATE_LOCK
2613 * Pads are activated from source pads to sinkpads.
2616 gst_element_pads_activate (GstElement * element, gboolean active)
2621 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2622 "pads_activate with active %d", active);
2624 iter = gst_element_iterate_src_pads (element);
2626 iterator_activate_fold_with_resync (iter,
2627 (GstIteratorFoldFunction) activate_pads, &active);
2628 gst_iterator_free (iter);
2629 if (G_UNLIKELY (!res))
2632 iter = gst_element_iterate_sink_pads (element);
2634 iterator_activate_fold_with_resync (iter,
2635 (GstIteratorFoldFunction) activate_pads, &active);
2636 gst_iterator_free (iter);
2637 if (G_UNLIKELY (!res))
2640 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2641 "pads_activate successful");
2648 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2649 "source pads_activate failed");
2654 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2655 "sink pads_activate failed");
2660 /* is called with STATE_LOCK */
2661 static GstStateChangeReturn
2662 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2664 GstState state, next;
2665 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2667 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2669 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2670 next = GST_STATE_TRANSITION_NEXT (transition);
2672 /* if the element already is in the given state, we just return success */
2673 if (next == GST_STATE_VOID_PENDING || state == next)
2676 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2677 "default handler tries setting state from %s to %s (%04x)",
2678 gst_element_state_get_name (state),
2679 gst_element_state_get_name (next), transition);
2681 switch (transition) {
2682 case GST_STATE_CHANGE_NULL_TO_READY:
2684 case GST_STATE_CHANGE_READY_TO_PAUSED:
2685 if (!gst_element_pads_activate (element, TRUE)) {
2686 result = GST_STATE_CHANGE_FAILURE;
2689 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2691 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2693 case GST_STATE_CHANGE_PAUSED_TO_READY:
2694 case GST_STATE_CHANGE_READY_TO_NULL:
2695 /* deactivate pads in both cases, since they are activated on
2696 ready->paused but the element might not have made it to paused */
2697 if (!gst_element_pads_activate (element, FALSE)) {
2698 result = GST_STATE_CHANGE_FAILURE;
2702 /* this will catch real but unhandled state changes;
2703 * can only be caused by:
2704 * - a new state was added
2705 * - somehow the element was asked to jump across an intermediate state
2707 g_warning ("Unhandled state change from %s to %s",
2708 gst_element_state_get_name (state),
2709 gst_element_state_get_name (next));
2716 GST_OBJECT_LOCK (element);
2717 result = GST_STATE_RETURN (element);
2718 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2719 "element is already in the %s state",
2720 gst_element_state_get_name (state));
2721 GST_OBJECT_UNLOCK (element);
2728 * gst_element_get_factory:
2729 * @element: a #GstElement to request the element factory of.
2731 * Retrieves the factory that was used to create this element.
2733 * Returns: (transfer none): the #GstElementFactory used for creating this
2734 * element. no refcounting is needed.
2737 gst_element_get_factory (GstElement * element)
2739 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2741 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2745 gst_element_dispose (GObject * object)
2747 GstElement *element = GST_ELEMENT_CAST (object);
2751 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2753 if (GST_STATE (element) != GST_STATE_NULL)
2756 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2757 "removing %d pads", g_list_length (element->pads));
2758 /* first we break all our links with the outside */
2759 while (element->pads && element->pads->data) {
2760 /* don't call _remove_pad with NULL */
2761 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2763 if (G_UNLIKELY (element->pads != NULL)) {
2764 g_critical ("could not remove pads from element %s",
2765 GST_STR_NULL (GST_OBJECT_NAME (object)));
2768 GST_OBJECT_LOCK (element);
2769 clock_p = &element->clock;
2770 bus_p = &element->bus;
2771 gst_object_replace ((GstObject **) clock_p, NULL);
2772 gst_object_replace ((GstObject **) bus_p, NULL);
2773 GST_OBJECT_UNLOCK (element);
2775 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2777 G_OBJECT_CLASS (parent_class)->dispose (object);
2786 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2788 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2790 "You need to explicitly set elements to the NULL state before\n"
2791 "dropping the final reference, to allow them to clean up.\n"
2792 "This problem may also be caused by a refcounting bug in the\n"
2793 "application or some element.\n",
2794 GST_OBJECT_NAME (element),
2795 gst_element_state_get_name (GST_STATE (element)),
2796 is_locked ? " (locked)" : "");
2802 gst_element_finalize (GObject * object)
2804 GstElement *element = GST_ELEMENT_CAST (object);
2806 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2808 g_cond_clear (&element->state_cond);
2809 g_rec_mutex_clear (&element->state_lock);
2811 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2813 G_OBJECT_CLASS (parent_class)->finalize (object);
2817 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2821 g_return_if_fail (GST_IS_ELEMENT (element));
2823 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2825 GST_OBJECT_LOCK (element);
2826 bus_p = &GST_ELEMENT_BUS (element);
2827 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2828 GST_OBJECT_UNLOCK (element);
2832 * gst_element_set_bus:
2833 * @element: a #GstElement to set the bus of.
2834 * @bus: (transfer none): the #GstBus to set.
2836 * Sets the bus of the element. Increases the refcount on the bus.
2837 * For internal use only, unless you're testing elements.
2842 gst_element_set_bus (GstElement * element, GstBus * bus)
2844 GstElementClass *oclass;
2846 g_return_if_fail (GST_IS_ELEMENT (element));
2848 oclass = GST_ELEMENT_GET_CLASS (element);
2850 if (oclass->set_bus)
2851 oclass->set_bus (element, bus);
2855 * gst_element_get_bus:
2856 * @element: a #GstElement to get the bus of.
2858 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2859 * bus for the application.
2861 * Returns: (transfer full): the element's #GstBus. unref after usage.
2866 gst_element_get_bus (GstElement * element)
2868 GstBus *result = NULL;
2870 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2872 GST_OBJECT_LOCK (element);
2873 if ((result = GST_ELEMENT_BUS (element)))
2874 gst_object_ref (result);
2875 GST_OBJECT_UNLOCK (element);
2877 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,