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"
99 /* Element signals and args */
115 static void gst_element_class_init (GstElementClass * klass);
116 static void gst_element_init (GstElement * element);
117 static void gst_element_base_class_init (gpointer g_class);
118 static void gst_element_base_class_finalize (gpointer g_class);
120 static void gst_element_dispose (GObject * object);
121 static void gst_element_finalize (GObject * object);
123 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
124 GstStateChange transition);
125 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
126 GstState * state, GstState * pending, GstClockTime timeout);
127 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
129 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
131 static gboolean gst_element_default_send_event (GstElement * element,
133 static gboolean gst_element_default_query (GstElement * element,
136 static GstPadTemplate
137 * gst_element_class_get_request_pad_template (GstElementClass *
138 element_class, const gchar * name);
140 static GstObjectClass *parent_class = NULL;
141 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
143 /* this is used in gstelementfactory.c:gst_element_register() */
144 GQuark __gst_elementclass_factory = 0;
147 gst_element_get_type (void)
149 static volatile gsize gst_element_type = 0;
151 if (g_once_init_enter (&gst_element_type)) {
153 static const GTypeInfo element_info = {
154 sizeof (GstElementClass),
155 gst_element_base_class_init,
156 gst_element_base_class_finalize,
157 (GClassInitFunc) gst_element_class_init,
162 (GInstanceInitFunc) gst_element_init,
166 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
167 &element_info, G_TYPE_FLAG_ABSTRACT);
169 __gst_elementclass_factory =
170 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
171 g_once_init_leave (&gst_element_type, _type);
173 return gst_element_type;
177 gst_element_class_init (GstElementClass * klass)
179 GObjectClass *gobject_class;
181 gobject_class = (GObjectClass *) klass;
183 parent_class = g_type_class_peek_parent (klass);
186 * GstElement::pad-added:
187 * @gstelement: the object which received the signal
188 * @new_pad: the pad that has been added
190 * a new #GstPad has been added to the element. Note that this signal will
191 * usually be emitted from the context of the streaming thread. Also keep in
192 * mind that if you add new elements to the pipeline in the signal handler
193 * you will need to set them to the desired target state with
194 * gst_element_set_state() or gst_element_sync_state_with_parent().
196 gst_element_signals[PAD_ADDED] =
197 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
198 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
199 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
201 * GstElement::pad-removed:
202 * @gstelement: the object which received the signal
203 * @old_pad: the pad that has been removed
205 * a #GstPad has been removed from the element
207 gst_element_signals[PAD_REMOVED] =
208 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
209 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
210 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
212 * GstElement::no-more-pads:
213 * @gstelement: the object which received the signal
215 * This signals that the element will not generate more dynamic pads.
216 * Note that this signal will usually be emitted from the context of
217 * the streaming thread.
219 gst_element_signals[NO_MORE_PADS] =
220 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
221 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
222 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
224 gobject_class->dispose = gst_element_dispose;
225 gobject_class->finalize = gst_element_finalize;
227 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
228 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
229 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
230 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
231 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
232 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
233 klass->numpadtemplates = 0;
235 klass->elementfactory = NULL;
239 gst_element_base_class_init (gpointer g_class)
241 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
242 GList *node, *padtemplates;
244 /* Copy the element details here so elements can inherit the
245 * details from their base class and classes only need to set
246 * the details in class_init instead of base_init */
247 element_class->metadata =
248 element_class->metadata ? gst_structure_copy (element_class->metadata) :
249 gst_structure_new_empty ("metadata");
251 /* Copy the pad templates so elements inherit them
252 * from their base class but elements can add pad templates in class_init
253 * instead of base_init.
255 padtemplates = g_list_copy (element_class->padtemplates);
256 for (node = padtemplates; node != NULL; node = node->next) {
257 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
258 gst_object_ref (tmpl);
260 element_class->padtemplates = padtemplates;
262 /* set the factory, see gst_element_register() */
263 element_class->elementfactory =
264 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
265 __gst_elementclass_factory);
266 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
267 element_class->elementfactory);
271 gst_element_base_class_finalize (gpointer g_class)
273 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
275 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
276 g_list_free (klass->padtemplates);
278 gst_structure_free (klass->metadata);
282 gst_element_init (GstElement * element)
284 GST_STATE (element) = GST_STATE_NULL;
285 GST_STATE_TARGET (element) = GST_STATE_NULL;
286 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
287 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
288 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
290 g_static_rec_mutex_init (&element->state_lock);
291 element->state_cond = g_cond_new ();
295 * gst_element_release_request_pad:
296 * @element: a #GstElement to release the request pad of.
297 * @pad: the #GstPad to release.
299 * Makes the element free the previously requested pad as obtained
300 * with gst_element_get_request_pad().
302 * This does not unref the pad. If the pad was created by using
303 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
304 * followed by gst_object_unref() to free the @pad.
309 gst_element_release_request_pad (GstElement * element, GstPad * pad)
311 GstElementClass *oclass;
313 g_return_if_fail (GST_IS_ELEMENT (element));
314 g_return_if_fail (GST_IS_PAD (pad));
316 oclass = GST_ELEMENT_GET_CLASS (element);
318 /* if the element implements a custom release function we call that, else we
319 * simply remove the pad from the element */
320 if (oclass->release_pad)
321 (oclass->release_pad) (element, pad);
323 gst_element_remove_pad (element, pad);
327 * gst_element_requires_clock:
328 * @element: a #GstElement to query
330 * Query if the element requires a clock.
332 * Returns: %TRUE if the element requires a clock
337 gst_element_requires_clock (GstElement * element)
341 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
343 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
349 * gst_element_provides_clock:
350 * @element: a #GstElement to query
352 * Query if the element provides a clock. A #GstClock provided by an
353 * element can be used as the global #GstClock for the pipeline.
354 * An element that can provide a clock is only required to do so in the PAUSED
355 * state, this means when it is fully negotiated and has allocated the resources
356 * to operate the clock.
358 * Returns: %TRUE if the element provides a clock
363 gst_element_provides_clock (GstElement * element)
367 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
369 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
375 * gst_element_provide_clock:
376 * @element: a #GstElement to query
378 * Get the clock provided by the given element.
379 * <note>An element is only required to provide a clock in the PAUSED
380 * state. Some elements can provide a clock in other states.</note>
382 * Returns: (transfer full): the GstClock provided by the element or %NULL
383 * if no clock could be provided. Unref after usage.
388 gst_element_provide_clock (GstElement * element)
390 GstClock *result = NULL;
391 GstElementClass *oclass;
393 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
395 oclass = GST_ELEMENT_GET_CLASS (element);
397 if (oclass->provide_clock)
398 result = oclass->provide_clock (element);
404 * gst_element_set_clock:
405 * @element: a #GstElement to set the clock for.
406 * @clock: the #GstClock to set for the element.
408 * Sets the clock for the element. This function increases the
409 * refcount on the clock. Any previously set clock on the object
412 * Returns: %TRUE if the element accepted the clock. An element can refuse a
413 * clock when it, for example, is not able to slave its internal clock to the
414 * @clock or when it requires a specific clock to operate.
419 gst_element_set_clock (GstElement * element, GstClock * clock)
421 GstElementClass *oclass;
425 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
426 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
428 oclass = GST_ELEMENT_GET_CLASS (element);
430 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
432 if (oclass->set_clock)
433 res = oclass->set_clock (element, clock);
436 /* only update the clock pointer if the element accepted the clock */
437 GST_OBJECT_LOCK (element);
438 clock_p = &element->clock;
439 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
440 GST_OBJECT_UNLOCK (element);
446 * gst_element_get_clock:
447 * @element: a #GstElement to get the clock of.
449 * Gets the currently configured clock of the element. This is the clock as was
450 * last set with gst_element_set_clock().
452 * Returns: (transfer full): the #GstClock of the element. unref after usage.
457 gst_element_get_clock (GstElement * element)
461 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
463 GST_OBJECT_LOCK (element);
464 if ((result = element->clock))
465 gst_object_ref (result);
466 GST_OBJECT_UNLOCK (element);
472 * gst_element_set_base_time:
473 * @element: a #GstElement.
474 * @time: the base time to set.
476 * Set the base time of an element. See gst_element_get_base_time().
481 gst_element_set_base_time (GstElement * element, GstClockTime time)
485 g_return_if_fail (GST_IS_ELEMENT (element));
487 GST_OBJECT_LOCK (element);
488 old = element->base_time;
489 element->base_time = time;
490 GST_OBJECT_UNLOCK (element);
492 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
493 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
494 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
498 * gst_element_get_base_time:
499 * @element: a #GstElement.
501 * Returns the base time of the element. The base time is the
502 * absolute time of the clock when this element was last put to
503 * PLAYING. Subtracting the base time from the clock time gives
504 * the running time of the element.
506 * Returns: the base time of the element.
511 gst_element_get_base_time (GstElement * element)
515 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
517 GST_OBJECT_LOCK (element);
518 result = element->base_time;
519 GST_OBJECT_UNLOCK (element);
525 * gst_element_set_start_time:
526 * @element: a #GstElement.
527 * @time: the base time to set.
529 * Set the start time of an element. The start time of the element is the
530 * running time of the element when it last went to the PAUSED state. In READY
531 * or after a flushing seek, it is set to 0.
533 * Toplevel elements like #GstPipeline will manage the start_time and
534 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
535 * on such a toplevel element will disable the distribution of the base_time to
536 * the children and can be useful if the application manages the base_time
537 * itself, for example if you want to synchronize capture from multiple
538 * pipelines, and you can also ensure that the pipelines have the same clock.
545 gst_element_set_start_time (GstElement * element, GstClockTime time)
549 g_return_if_fail (GST_IS_ELEMENT (element));
551 GST_OBJECT_LOCK (element);
552 old = GST_ELEMENT_START_TIME (element);
553 GST_ELEMENT_START_TIME (element) = time;
554 GST_OBJECT_UNLOCK (element);
556 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
557 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
558 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
562 * gst_element_get_start_time:
563 * @element: a #GstElement.
565 * Returns the start time of the element. The start time is the
566 * running time of the clock when this element was last put to PAUSED.
568 * Usually the start_time is managed by a toplevel element such as
573 * Returns: the start time of the element.
578 gst_element_get_start_time (GstElement * element)
582 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
584 GST_OBJECT_LOCK (element);
585 result = GST_ELEMENT_START_TIME (element);
586 GST_OBJECT_UNLOCK (element);
592 * gst_element_is_indexable:
593 * @element: a #GstElement.
595 * Queries if the element can be indexed.
597 * Returns: TRUE if the element can be indexed.
602 gst_element_is_indexable (GstElement * element)
606 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
608 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
614 * gst_element_set_index:
615 * @element: a #GstElement.
616 * @index: (transfer none): a #GstIndex.
618 * Set @index on the element. The refcount of the index
619 * will be increased, any previously set index is unreffed.
624 gst_element_set_index (GstElement * element, GstIndex * index)
626 GstElementClass *oclass;
628 g_return_if_fail (GST_IS_ELEMENT (element));
629 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
631 oclass = GST_ELEMENT_GET_CLASS (element);
633 if (oclass->set_index)
634 oclass->set_index (element, index);
638 * gst_element_get_index:
639 * @element: a #GstElement.
641 * Gets the index from the element.
643 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
644 * element. unref after usage.
649 gst_element_get_index (GstElement * element)
651 GstElementClass *oclass;
652 GstIndex *result = NULL;
654 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
656 oclass = GST_ELEMENT_GET_CLASS (element);
658 if (oclass->get_index)
659 result = oclass->get_index (element);
665 * gst_element_add_pad:
666 * @element: a #GstElement to add the pad to.
667 * @pad: (transfer full): the #GstPad to add to the element.
669 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
670 * see gst_object_set_parent() for refcounting information.
672 * Pads are not automatically activated so elements should perform the needed
673 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
674 * state. See gst_pad_set_active() for more information about activating pads.
676 * The pad and the element should be unlocked when calling this function.
678 * This function will emit the #GstElement::pad-added signal on the element.
680 * Returns: %TRUE if the pad could be added. This function can fail when
681 * a pad with the same name already existed or the pad already had another
687 gst_element_add_pad (GstElement * element, GstPad * pad)
692 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
693 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
695 /* locking pad to look at the name */
696 GST_OBJECT_LOCK (pad);
697 pad_name = g_strdup (GST_PAD_NAME (pad));
698 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
699 GST_STR_NULL (pad_name));
700 flushing = GST_PAD_IS_FLUSHING (pad);
701 GST_OBJECT_UNLOCK (pad);
703 /* then check to see if there's already a pad by that name here */
704 GST_OBJECT_LOCK (element);
705 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
708 /* try to set the pad's parent */
709 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
710 GST_OBJECT_CAST (element))))
713 /* check for flushing pads */
714 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
715 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
716 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
717 "use gst_pad_set_active(pad,TRUE) before adding it.",
718 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
720 GST_OBJECT_LOCK (pad);
721 GST_PAD_UNSET_FLUSHING (pad);
722 GST_OBJECT_UNLOCK (pad);
727 /* add it to the list */
728 switch (gst_pad_get_direction (pad)) {
730 element->srcpads = g_list_prepend (element->srcpads, pad);
731 element->numsrcpads++;
734 element->sinkpads = g_list_prepend (element->sinkpads, pad);
735 element->numsinkpads++;
740 element->pads = g_list_prepend (element->pads, pad);
742 element->pads_cookie++;
743 GST_OBJECT_UNLOCK (element);
745 /* emit the PAD_ADDED signal */
746 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
753 g_critical ("Padname %s is not unique in element %s, not adding",
754 pad_name, GST_ELEMENT_NAME (element));
755 GST_OBJECT_UNLOCK (element);
762 ("Pad %s already has parent when trying to add to element %s",
763 pad_name, GST_ELEMENT_NAME (element));
764 GST_OBJECT_UNLOCK (element);
770 GST_OBJECT_LOCK (pad);
772 ("Trying to add pad %s to element %s, but it has no direction",
773 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
774 GST_OBJECT_UNLOCK (pad);
775 GST_OBJECT_UNLOCK (element);
781 * gst_element_remove_pad:
782 * @element: a #GstElement to remove pad from.
783 * @pad: (transfer none): the #GstPad to remove from the element.
785 * Removes @pad from @element. @pad will be destroyed if it has not been
786 * referenced elsewhere using gst_object_unparent().
788 * This function is used by plugin developers and should not be used
789 * by applications. Pads that were dynamically requested from elements
790 * with gst_element_get_request_pad() should be released with the
791 * gst_element_release_request_pad() function instead.
793 * Pads are not automatically deactivated so elements should perform the needed
794 * steps to deactivate the pad in case this pad is removed in the PAUSED or
795 * PLAYING state. See gst_pad_set_active() for more information about
798 * The pad and the element should be unlocked when calling this function.
800 * This function will emit the #GstElement::pad-removed signal on the element.
802 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
803 * pad does not belong to the provided element.
808 gst_element_remove_pad (GstElement * element, GstPad * pad)
812 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
813 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
815 /* locking pad to look at the name and parent */
816 GST_OBJECT_LOCK (pad);
817 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
818 GST_STR_NULL (GST_PAD_NAME (pad)));
820 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
822 GST_OBJECT_UNLOCK (pad);
825 if ((peer = gst_pad_get_peer (pad))) {
826 /* window for MT unsafeness, someone else could unlink here
827 * and then we call unlink with wrong pads. The unlink
828 * function would catch this and safely return failed. */
829 if (GST_PAD_IS_SRC (pad))
830 gst_pad_unlink (pad, peer);
832 gst_pad_unlink (peer, pad);
834 gst_object_unref (peer);
837 GST_OBJECT_LOCK (element);
838 /* remove it from the list */
839 switch (gst_pad_get_direction (pad)) {
841 element->srcpads = g_list_remove (element->srcpads, pad);
842 element->numsrcpads--;
845 element->sinkpads = g_list_remove (element->sinkpads, pad);
846 element->numsinkpads--;
849 g_critical ("Removing pad without direction???");
852 element->pads = g_list_remove (element->pads, pad);
854 element->pads_cookie++;
855 GST_OBJECT_UNLOCK (element);
857 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
858 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
860 gst_object_unparent (GST_OBJECT_CAST (pad));
867 /* locking order is element > pad */
868 GST_OBJECT_UNLOCK (pad);
870 GST_OBJECT_LOCK (element);
871 GST_OBJECT_LOCK (pad);
872 g_critical ("Padname %s:%s does not belong to element %s when removing",
873 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
874 GST_OBJECT_UNLOCK (pad);
875 GST_OBJECT_UNLOCK (element);
881 * gst_element_no_more_pads:
882 * @element: a #GstElement
884 * Use this function to signal that the element does not expect any more pads
885 * to show up in the current pipeline. This function should be called whenever
886 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
887 * pad templates use this in combination with autopluggers to figure out that
888 * the element is done initializing its pads.
890 * This function emits the #GstElement::no-more-pads signal.
895 gst_element_no_more_pads (GstElement * element)
897 g_return_if_fail (GST_IS_ELEMENT (element));
899 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
903 pad_compare_name (GstPad * pad1, const gchar * name)
907 GST_OBJECT_LOCK (pad1);
908 result = strcmp (GST_PAD_NAME (pad1), name);
909 GST_OBJECT_UNLOCK (pad1);
915 * gst_element_get_static_pad:
916 * @element: a #GstElement to find a static pad of.
917 * @name: the name of the static #GstPad to retrieve.
919 * Retrieves a pad from @element by name. This version only retrieves
920 * already-existing (i.e. 'static') pads.
922 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
928 gst_element_get_static_pad (GstElement * element, const gchar * name)
931 GstPad *result = NULL;
933 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
934 g_return_val_if_fail (name != NULL, NULL);
936 GST_OBJECT_LOCK (element);
938 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
940 result = GST_PAD_CAST (find->data);
941 gst_object_ref (result);
944 if (result == NULL) {
945 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
946 name, GST_ELEMENT_NAME (element));
948 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
949 GST_ELEMENT_NAME (element), name);
951 GST_OBJECT_UNLOCK (element);
957 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
958 const gchar * name, const GstCaps * caps)
960 GstPad *newpad = NULL;
961 GstElementClass *oclass;
963 oclass = GST_ELEMENT_GET_CLASS (element);
965 #ifndef G_DISABLE_CHECKS
966 /* Some sanity checking here */
970 /* Is this the template name? */
971 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
972 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
974 const gchar *str, *data;
977 /* Otherwise check if it's a valid name for the name template */
978 str = strchr (templ->name_template, '%');
979 g_return_val_if_fail (str != NULL, NULL);
980 g_return_val_if_fail (strncmp (templ->name_template, name,
981 str - templ->name_template) == 0, NULL);
982 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
984 data = name + (str - templ->name_template);
986 /* Can either be %s or %d or %u, do sanity checking for %d */
987 if (*(str + 1) == 'd') {
991 tmp = g_ascii_strtoll (data, &endptr, 10);
992 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
993 && *endptr == '\0', NULL);
994 } else if (*(str + 1) == 'u') {
998 tmp = g_ascii_strtoull (data, &endptr, 10);
999 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
1003 pad = gst_element_get_static_pad (element, name);
1005 gst_object_unref (pad);
1006 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1007 g_critical ("Element %s already has a pad named %s, the behaviour of "
1008 " gst_element_get_request_pad() for existing pads is undefined!",
1009 GST_ELEMENT_NAME (element), name);
1014 if (oclass->request_new_pad)
1015 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1018 gst_object_ref (newpad);
1024 * gst_element_get_request_pad:
1025 * @element: a #GstElement to find a request pad of.
1026 * @name: the name of the request #GstPad to retrieve.
1028 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1029 * retrieves request pads. The pad should be released with
1030 * gst_element_release_request_pad().
1032 * This method is slow and will be deprecated in the future. New code should
1033 * use gst_element_request_pad() with the requested template.
1035 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1036 * Release after usage.
1039 gst_element_get_request_pad (GstElement * element, const gchar * name)
1041 GstPadTemplate *templ = NULL;
1043 const gchar *req_name = NULL;
1044 gboolean templ_found = FALSE;
1047 gchar *str, *endptr = NULL;
1048 GstElementClass *class;
1050 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1051 g_return_val_if_fail (name != NULL, NULL);
1053 class = GST_ELEMENT_GET_CLASS (element);
1055 /* if the name contains a %, we assume it's the complete template name. Get
1056 * the template and try to get a pad */
1057 if (strstr (name, "%")) {
1058 templ = gst_element_class_get_request_pad_template (class, name);
1063 /* there is no % in the name, try to find a matching template */
1064 list = class->padtemplates;
1065 while (!templ_found && list) {
1066 templ = (GstPadTemplate *) list->data;
1067 if (templ->presence == GST_PAD_REQUEST) {
1068 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1069 templ->name_template);
1070 /* see if we find an exact match */
1071 if (strcmp (name, templ->name_template) == 0) {
1076 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1077 and %d and %u, occurring at the end of the name_template, are the only
1079 else if ((str = strchr (templ->name_template, '%'))
1080 && strncmp (templ->name_template, name,
1081 str - templ->name_template) == 0
1082 && strlen (name) > str - templ->name_template) {
1083 data = name + (str - templ->name_template);
1084 if (*(str + 1) == 'd') {
1088 tmp = strtol (data, &endptr, 10);
1089 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1095 } else if (*(str + 1) == 'u') {
1099 tmp = strtoul (data, &endptr, 10);
1100 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1120 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1126 * gst_element_request_pad:
1127 * @element: a #GstElement to find a request pad of.
1128 * @templ: a #GstPadTemplate of which we want a pad of.
1129 * @name: (transfer none) (allow-none): the name of the request #GstPad
1130 * to retrieve. Can be %NULL.
1131 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1132 * request. Can be %NULL.
1134 * Retrieves a request pad from the element according to the provided template.
1135 * Pad templates can be looked up using
1136 * gst_element_factory_get_static_pad_templates().
1138 * The pad should be released with gst_element_release_request_pad().
1140 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1141 * Release after usage.
1146 gst_element_request_pad (GstElement * element,
1147 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1149 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1150 g_return_val_if_fail (templ != NULL, NULL);
1152 return _gst_element_request_pad (element, templ, name, caps);
1155 static GstIterator *
1156 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1158 GstIterator *result;
1160 GST_OBJECT_LOCK (element);
1161 result = gst_iterator_new_list (GST_TYPE_PAD,
1162 GST_OBJECT_GET_LOCK (element),
1163 &element->pads_cookie, padlist, (GObject *) element, NULL);
1164 GST_OBJECT_UNLOCK (element);
1170 * gst_element_iterate_pads:
1171 * @element: a #GstElement to iterate pads of.
1173 * Retrieves an iterator of @element's pads. The iterator should
1174 * be freed after usage. Also more specialized iterators exists such as
1175 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1177 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1183 gst_element_iterate_pads (GstElement * element)
1185 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1187 return gst_element_iterate_pad_list (element, &element->pads);
1191 * gst_element_iterate_src_pads:
1192 * @element: a #GstElement.
1194 * Retrieves an iterator of @element's source pads.
1196 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1202 gst_element_iterate_src_pads (GstElement * element)
1204 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1206 return gst_element_iterate_pad_list (element, &element->srcpads);
1210 * gst_element_iterate_sink_pads:
1211 * @element: a #GstElement.
1213 * Retrieves an iterator of @element's sink pads.
1215 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1221 gst_element_iterate_sink_pads (GstElement * element)
1223 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1225 return gst_element_iterate_pad_list (element, &element->sinkpads);
1229 * gst_element_class_add_pad_template:
1230 * @klass: the #GstElementClass to add the pad template to.
1231 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1233 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1234 * functions of classes. If a pad template with the same name as an already
1235 * existing one is added the old one is replaced by the new one.
1239 gst_element_class_add_pad_template (GstElementClass * klass,
1240 GstPadTemplate * templ)
1242 GList *template_list = klass->padtemplates;
1244 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1245 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1247 /* If we already have a pad template with the same name replace the
1249 while (template_list) {
1250 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1252 /* Found pad with the same name, replace and return */
1253 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1254 gst_object_unref (padtempl);
1255 template_list->data = templ;
1258 template_list = g_list_next (template_list);
1261 /* Take ownership of the floating ref */
1262 g_object_ref_sink (templ);
1264 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1265 klass->numpadtemplates++;
1269 * gst_element_class_add_metadata:
1270 * @klass: class to set metadata for
1271 * @key: the key to set
1272 * @value: the value to set
1274 * Set @key with @value as metadata in @klass.
1277 gst_element_class_add_metadata (GstElementClass * klass,
1278 const gchar * key, const gchar * value)
1280 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1281 g_return_if_fail (key != NULL);
1282 g_return_if_fail (value != NULL);
1284 gst_structure_set ((GstStructure *) klass->metadata,
1285 key, G_TYPE_STRING, value, NULL);
1289 * gst_element_class_set_metadata:
1290 * @klass: class to set metadata for
1291 * @longname: The long English name of the element. E.g. "File Sink"
1292 * @classification: String describing the type of element, as an unordered list
1293 * separated with slashes ('/'). See draft-klass.txt of the design docs
1294 * for more details and common types. E.g: "Sink/File"
1295 * @description: Sentence describing the purpose of the element.
1296 * E.g: "Write stream to a file"
1297 * @author: Name and contact details of the author(s). Use \n to separate
1298 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1300 * Sets the detailed information for a #GstElementClass.
1301 * <note>This function is for use in _class_init functions only.</note>
1304 gst_element_class_set_metadata (GstElementClass * klass,
1305 const gchar * longname, const gchar * classification,
1306 const gchar * description, const gchar * author)
1308 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1310 gst_structure_set ((GstStructure *) klass->metadata,
1311 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1312 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1313 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1314 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1318 * gst_element_class_get_metadata:
1319 * @klass: class to get metadata for
1320 * @key: the key to get
1322 * Get metadata with @key in @klass.
1324 * Returns: the metadata for @key.
1327 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1329 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1330 g_return_val_if_fail (key != NULL, NULL);
1332 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1336 * gst_element_class_get_pad_template_list:
1337 * @element_class: a #GstElementClass to get pad templates of.
1339 * Retrieves a list of the pad templates associated with @element_class. The
1340 * list must not be modified by the calling code.
1341 * <note>If you use this function in the #GInstanceInitFunc of an object class
1342 * that has subclasses, make sure to pass the g_class parameter of the
1343 * #GInstanceInitFunc here.</note>
1345 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1349 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1351 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1353 return element_class->padtemplates;
1357 * gst_element_class_get_pad_template:
1358 * @element_class: a #GstElementClass to get the pad template of.
1359 * @name: the name of the #GstPadTemplate to get.
1361 * Retrieves a padtemplate from @element_class with the given name.
1362 * <note>If you use this function in the #GInstanceInitFunc of an object class
1363 * that has subclasses, make sure to pass the g_class parameter of the
1364 * #GInstanceInitFunc here.</note>
1366 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1367 * if none was found. No unreferencing is necessary.
1370 gst_element_class_get_pad_template (GstElementClass *
1371 element_class, const gchar * name)
1375 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1376 g_return_val_if_fail (name != NULL, NULL);
1378 padlist = element_class->padtemplates;
1381 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1383 if (strcmp (padtempl->name_template, name) == 0)
1386 padlist = g_list_next (padlist);
1392 static GstPadTemplate *
1393 gst_element_class_get_request_pad_template (GstElementClass *
1394 element_class, const gchar * name)
1396 GstPadTemplate *tmpl;
1398 tmpl = gst_element_class_get_pad_template (element_class, name);
1399 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1405 /* get a random pad on element of the given direction.
1406 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1409 gst_element_get_random_pad (GstElement * element,
1410 gboolean need_linked, GstPadDirection dir)
1412 GstPad *result = NULL;
1415 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1419 GST_OBJECT_LOCK (element);
1420 pads = element->srcpads;
1423 GST_OBJECT_LOCK (element);
1424 pads = element->sinkpads;
1427 goto wrong_direction;
1429 for (; pads; pads = g_list_next (pads)) {
1430 GstPad *pad = GST_PAD_CAST (pads->data);
1432 GST_OBJECT_LOCK (pad);
1433 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1434 GST_DEBUG_PAD_NAME (pad));
1436 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1437 /* if we require a linked pad, and it is not linked, continue the
1439 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1440 GST_DEBUG_PAD_NAME (pad));
1441 GST_OBJECT_UNLOCK (pad);
1444 /* found a pad, stop search */
1445 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1446 GST_DEBUG_PAD_NAME (pad));
1447 GST_OBJECT_UNLOCK (pad);
1453 gst_object_ref (result);
1455 GST_OBJECT_UNLOCK (element);
1459 /* ERROR handling */
1462 g_warning ("unknown pad direction %d", dir);
1468 gst_element_default_send_event (GstElement * element, GstEvent * event)
1470 gboolean result = FALSE;
1473 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1474 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1475 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1478 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1479 "pushing %s event to random %s pad %s:%s",
1480 GST_EVENT_TYPE_NAME (event),
1481 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1482 GST_DEBUG_PAD_NAME (pad));
1484 result = gst_pad_push_event (pad, event);
1485 gst_object_unref (pad);
1487 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1488 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1489 gst_event_unref (event);
1495 * gst_element_send_event:
1496 * @element: a #GstElement to send the event to.
1497 * @event: (transfer full): the #GstEvent to send to the element.
1499 * Sends an event to an element. If the element doesn't implement an
1500 * event handler, the event will be pushed on a random linked sink pad for
1501 * upstream events or a random linked source pad for downstream events.
1503 * This function takes owership of the provided event so you should
1504 * gst_event_ref() it if you want to reuse the event after this call.
1506 * Returns: %TRUE if the event was handled.
1511 gst_element_send_event (GstElement * element, GstEvent * event)
1513 GstElementClass *oclass;
1514 gboolean result = FALSE;
1516 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1517 g_return_val_if_fail (event != NULL, FALSE);
1519 oclass = GST_ELEMENT_GET_CLASS (element);
1521 GST_STATE_LOCK (element);
1522 if (oclass->send_event) {
1523 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1524 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1525 result = oclass->send_event (element, event);
1527 result = gst_element_default_send_event (element, event);
1529 GST_STATE_UNLOCK (element);
1536 * @element: a #GstElement to send the event to.
1537 * @rate: The new playback rate
1538 * @format: The format of the seek values
1539 * @flags: The optional seek flags.
1540 * @cur_type: The type and flags for the new current position
1541 * @cur: The value of the new current position
1542 * @stop_type: The type and flags for the new stop position
1543 * @stop: The value of the new stop position
1545 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1546 * the parameters. The seek event is sent to the element using
1547 * gst_element_send_event().
1549 * Returns: %TRUE if the event was handled.
1554 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1555 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1556 GstSeekType stop_type, gint64 stop)
1561 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1564 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1565 result = gst_element_send_event (element, event);
1571 gst_element_default_query (GstElement * element, GstQuery * query)
1573 gboolean result = FALSE;
1576 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1578 result = gst_pad_query (pad, query);
1580 gst_object_unref (pad);
1582 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1584 GstPad *peer = gst_pad_get_peer (pad);
1587 result = gst_pad_query (peer, query);
1589 gst_object_unref (peer);
1591 gst_object_unref (pad);
1598 * gst_element_query:
1599 * @element: a #GstElement to perform the query on.
1600 * @query: (transfer none): the #GstQuery.
1602 * Performs a query on the given element.
1604 * For elements that don't implement a query handler, this function
1605 * forwards the query to a random srcpad or to the peer of a
1606 * random linked sinkpad of this element.
1608 * Please note that some queries might need a running pipeline to work.
1610 * Returns: TRUE if the query could be performed.
1615 gst_element_query (GstElement * element, GstQuery * query)
1617 GstElementClass *oclass;
1618 gboolean result = FALSE;
1620 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1621 g_return_val_if_fail (query != NULL, FALSE);
1623 oclass = GST_ELEMENT_GET_CLASS (element);
1625 if (oclass->query) {
1626 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1627 GST_ELEMENT_NAME (element));
1628 result = oclass->query (element, query);
1630 result = gst_element_default_query (element, query);
1636 * gst_element_post_message:
1637 * @element: a #GstElement posting the message
1638 * @message: (transfer full): a #GstMessage to post
1640 * Post a message on the element's #GstBus. This function takes ownership of the
1641 * message; if you want to access the message after this call, you should add an
1642 * additional reference before calling.
1644 * Returns: %TRUE if the message was successfully posted. The function returns
1645 * %FALSE if the element did not have a bus.
1650 gst_element_post_message (GstElement * element, GstMessage * message)
1653 gboolean result = FALSE;
1655 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1656 g_return_val_if_fail (message != NULL, FALSE);
1658 GST_OBJECT_LOCK (element);
1661 if (G_UNLIKELY (bus == NULL))
1664 gst_object_ref (bus);
1665 GST_OBJECT_UNLOCK (element);
1667 /* we release the element lock when posting the message so that any
1668 * (synchronous) message handlers can operate on the element */
1669 result = gst_bus_post (bus, message);
1670 gst_object_unref (bus);
1677 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1678 "not posting message %p: no bus", message);
1679 GST_OBJECT_UNLOCK (element);
1680 gst_message_unref (message);
1686 * _gst_element_error_printf:
1687 * @format: the printf-like format to use, or %NULL
1689 * This function is only used internally by the gst_element_error() macro.
1691 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1697 _gst_element_error_printf (const gchar * format, ...)
1707 va_start (args, format);
1708 buffer = g_strdup_vprintf (format, args);
1714 * gst_element_message_full:
1715 * @element: a #GstElement to send message from
1716 * @type: the #GstMessageType
1717 * @domain: the GStreamer GError domain this message belongs to
1718 * @code: the GError code belonging to the domain
1719 * @text: (allow-none) (transfer full): an allocated text string to be used
1720 * as a replacement for the default message connected to code,
1722 * @debug: (allow-none) (transfer full): an allocated debug message to be
1723 * used as a replacement for the default debugging information,
1725 * @file: the source code file where the error was generated
1726 * @function: the source code function where the error was generated
1727 * @line: the source code line where the error was generated
1729 * Post an error, warning or info message on the bus from inside an element.
1731 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1732 * #GST_MESSAGE_INFO.
1736 void gst_element_message_full
1737 (GstElement * element, GstMessageType type,
1738 GQuark domain, gint code, gchar * text,
1739 gchar * debug, const gchar * file, const gchar * function, gint line)
1741 GError *gerror = NULL;
1745 gboolean has_debug = TRUE;
1746 GstMessage *message = NULL;
1749 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1750 g_return_if_fail (GST_IS_ELEMENT (element));
1751 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1752 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1754 /* check if we send the given text or the default error text */
1755 if ((text == NULL) || (text[0] == 0)) {
1756 /* text could have come from g_strdup_printf (""); */
1758 sent_text = gst_error_get_message (domain, code);
1762 /* construct a sent_debug with extra information from source */
1763 if ((debug == NULL) || (debug[0] == 0)) {
1764 /* debug could have come from g_strdup_printf (""); */
1768 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1770 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1771 file, line, function, name, debug);
1773 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1774 file, line, function, name);
1778 /* create gerror and post message */
1779 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1781 gerror = g_error_new_literal (domain, code, sent_text);
1784 case GST_MESSAGE_ERROR:
1786 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1788 case GST_MESSAGE_WARNING:
1789 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1792 case GST_MESSAGE_INFO:
1793 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1797 g_assert_not_reached ();
1800 gst_element_post_message (element, message);
1802 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1803 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1806 g_error_free (gerror);
1807 g_free (sent_debug);
1812 * gst_element_is_locked_state:
1813 * @element: a #GstElement.
1815 * Checks if the state of an element is locked.
1816 * If the state of an element is locked, state changes of the parent don't
1817 * affect the element.
1818 * This way you can leave currently unused elements inside bins. Just lock their
1819 * state before changing the state from #GST_STATE_NULL.
1823 * Returns: TRUE, if the element's state is locked.
1826 gst_element_is_locked_state (GstElement * element)
1830 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1832 GST_OBJECT_LOCK (element);
1833 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1834 GST_OBJECT_UNLOCK (element);
1840 * gst_element_set_locked_state:
1841 * @element: a #GstElement
1842 * @locked_state: TRUE to lock the element's state
1844 * Locks the state of an element, so state changes of the parent don't affect
1845 * this element anymore.
1849 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1850 * or the elements state-locking needed no change.
1853 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1857 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1859 GST_OBJECT_LOCK (element);
1860 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1862 if (G_UNLIKELY (old == locked_state))
1866 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1867 GST_ELEMENT_NAME (element));
1868 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1870 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1871 GST_ELEMENT_NAME (element));
1872 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1874 GST_OBJECT_UNLOCK (element);
1880 GST_CAT_DEBUG (GST_CAT_STATES,
1881 "elements %s was already in locked state %d",
1882 GST_ELEMENT_NAME (element), old);
1883 GST_OBJECT_UNLOCK (element);
1890 * gst_element_sync_state_with_parent:
1891 * @element: a #GstElement.
1893 * Tries to change the state of the element to the same as its parent.
1894 * If this function returns FALSE, the state of element is undefined.
1896 * Returns: TRUE, if the element's state could be synced to the parent's state.
1901 gst_element_sync_state_with_parent (GstElement * element)
1905 GstStateChangeReturn ret;
1907 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1909 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1910 GstState parent_current, parent_pending;
1912 GST_OBJECT_LOCK (parent);
1913 parent_current = GST_STATE (parent);
1914 parent_pending = GST_STATE_PENDING (parent);
1915 GST_OBJECT_UNLOCK (parent);
1917 /* set to pending if there is one, else we set it to the current state of
1919 if (parent_pending != GST_STATE_VOID_PENDING)
1920 target = parent_pending;
1922 target = parent_current;
1924 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1925 "syncing state (%s) to parent %s %s (%s, %s)",
1926 gst_element_state_get_name (GST_STATE (element)),
1927 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1928 gst_element_state_get_name (parent_current),
1929 gst_element_state_get_name (parent_pending));
1931 ret = gst_element_set_state (element, target);
1932 if (ret == GST_STATE_CHANGE_FAILURE)
1935 gst_object_unref (parent);
1939 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1946 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1947 "syncing state failed (%s)",
1948 gst_element_state_change_return_get_name (ret));
1949 gst_object_unref (parent);
1955 static GstStateChangeReturn
1956 gst_element_get_state_func (GstElement * element,
1957 GstState * state, GstState * pending, GstClockTime timeout)
1959 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1960 GstState old_pending;
1962 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1963 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1965 GST_OBJECT_LOCK (element);
1966 ret = GST_STATE_RETURN (element);
1967 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1968 gst_element_state_change_return_get_name (ret));
1970 /* we got an error, report immediately */
1971 if (ret == GST_STATE_CHANGE_FAILURE)
1974 /* we got no_preroll, report immediately */
1975 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1978 /* no need to wait async if we are not async */
1979 if (ret != GST_STATE_CHANGE_ASYNC)
1982 old_pending = GST_STATE_PENDING (element);
1983 if (old_pending != GST_STATE_VOID_PENDING) {
1984 GTimeVal *timeval, abstimeout;
1987 if (timeout != GST_CLOCK_TIME_NONE) {
1988 glong add = timeout / 1000;
1993 /* make timeout absolute */
1994 g_get_current_time (&abstimeout);
1995 g_time_val_add (&abstimeout, add);
1996 timeval = &abstimeout;
2000 /* get cookie to detect state changes during waiting */
2001 cookie = element->state_cookie;
2003 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2004 "waiting for element to commit state");
2006 /* we have a pending state change, wait for it to complete */
2007 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2008 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2009 /* timeout triggered */
2010 ret = GST_STATE_CHANGE_ASYNC;
2012 if (cookie != element->state_cookie)
2015 /* could be success or failure */
2016 if (old_pending == GST_STATE (element)) {
2017 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2018 ret = GST_STATE_CHANGE_SUCCESS;
2020 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2021 ret = GST_STATE_CHANGE_FAILURE;
2024 /* if nothing is pending anymore we can return SUCCESS */
2025 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2026 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2027 ret = GST_STATE_CHANGE_SUCCESS;
2033 *state = GST_STATE (element);
2035 *pending = GST_STATE_PENDING (element);
2037 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2038 "state current: %s, pending: %s, result: %s",
2039 gst_element_state_get_name (GST_STATE (element)),
2040 gst_element_state_get_name (GST_STATE_PENDING (element)),
2041 gst_element_state_change_return_get_name (ret));
2042 GST_OBJECT_UNLOCK (element);
2049 *state = GST_STATE_VOID_PENDING;
2051 *pending = GST_STATE_VOID_PENDING;
2053 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2055 GST_OBJECT_UNLOCK (element);
2057 return GST_STATE_CHANGE_FAILURE;
2062 * gst_element_get_state:
2063 * @element: a #GstElement to get the state of.
2064 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2066 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2067 * state. Can be %NULL.
2068 * @timeout: a #GstClockTime to specify the timeout for an async
2069 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2071 * Gets the state of the element.
2073 * For elements that performed an ASYNC state change, as reported by
2074 * gst_element_set_state(), this function will block up to the
2075 * specified timeout value for the state change to complete.
2076 * If the element completes the state change or goes into
2077 * an error, this function returns immediately with a return value of
2078 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2080 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2081 * returns the current and pending state immediately.
2083 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2084 * successfully changed its state but is not able to provide data yet.
2085 * This mostly happens for live sources that only produce data in
2086 * %GST_STATE_PLAYING. While the state change return is equivalent to
2087 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2088 * some sink elements might not be able to complete their state change because
2089 * an element is not producing data to complete the preroll. When setting the
2090 * element to playing, the preroll will complete and playback will start.
2092 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2093 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2094 * element is still performing a state change or
2095 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2099 GstStateChangeReturn
2100 gst_element_get_state (GstElement * element,
2101 GstState * state, GstState * pending, GstClockTime timeout)
2103 GstElementClass *oclass;
2104 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2106 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2108 oclass = GST_ELEMENT_GET_CLASS (element);
2110 if (oclass->get_state)
2111 result = (oclass->get_state) (element, state, pending, timeout);
2117 * gst_element_abort_state:
2118 * @element: a #GstElement to abort the state of.
2120 * Abort the state change of the element. This function is used
2121 * by elements that do asynchronous state changes and find out
2122 * something is wrong.
2124 * This function should be called with the STATE_LOCK held.
2129 gst_element_abort_state (GstElement * element)
2133 #ifndef GST_DISABLE_GST_DEBUG
2137 g_return_if_fail (GST_IS_ELEMENT (element));
2139 GST_OBJECT_LOCK (element);
2140 pending = GST_STATE_PENDING (element);
2142 if (pending == GST_STATE_VOID_PENDING ||
2143 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2144 goto nothing_aborted;
2146 #ifndef GST_DISABLE_GST_DEBUG
2147 old_state = GST_STATE (element);
2149 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2150 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2151 gst_element_state_get_name (pending));
2155 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2157 GST_STATE_BROADCAST (element);
2158 GST_OBJECT_UNLOCK (element);
2164 GST_OBJECT_UNLOCK (element);
2169 /* Not static because GstBin has manual state handling too */
2171 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2172 GstState newstate, GstState pending)
2174 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2175 GstMessage *message;
2177 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2178 "notifying about state-changed %s to %s (%s pending)",
2179 gst_element_state_get_name (oldstate),
2180 gst_element_state_get_name (newstate),
2181 gst_element_state_get_name (pending));
2183 if (klass->state_changed)
2184 klass->state_changed (element, oldstate, newstate, pending);
2186 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2187 oldstate, newstate, pending);
2188 gst_element_post_message (element, message);
2192 * gst_element_continue_state:
2193 * @element: a #GstElement to continue the state change of.
2194 * @ret: The previous state return value
2196 * Commit the state change of the element and proceed to the next
2197 * pending state if any. This function is used
2198 * by elements that do asynchronous state changes.
2199 * The core will normally call this method automatically when an
2200 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2202 * If after calling this method the element still has not reached
2203 * the pending state, the next state change is performed.
2205 * This method is used internally and should normally not be called by plugins
2208 * Returns: The result of the commit state change.
2212 GstStateChangeReturn
2213 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2215 GstStateChangeReturn old_ret;
2216 GstState old_state, old_next;
2217 GstState current, next, pending;
2218 GstStateChange transition;
2220 GST_OBJECT_LOCK (element);
2221 old_ret = GST_STATE_RETURN (element);
2222 GST_STATE_RETURN (element) = ret;
2223 pending = GST_STATE_PENDING (element);
2225 /* check if there is something to commit */
2226 if (pending == GST_STATE_VOID_PENDING)
2227 goto nothing_pending;
2229 old_state = GST_STATE (element);
2230 /* this is the state we should go to next */
2231 old_next = GST_STATE_NEXT (element);
2232 /* update current state */
2233 current = GST_STATE (element) = old_next;
2235 /* see if we reached the final state */
2236 if (pending == current)
2239 next = GST_STATE_GET_NEXT (current, pending);
2240 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2242 GST_STATE_NEXT (element) = next;
2244 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2245 GST_OBJECT_UNLOCK (element);
2247 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2248 "committing state from %s to %s, pending %s, next %s",
2249 gst_element_state_get_name (old_state),
2250 gst_element_state_get_name (old_next),
2251 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2253 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2255 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2256 "continue state change %s to %s, final %s",
2257 gst_element_state_get_name (current),
2258 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2260 ret = gst_element_change_state (element, transition);
2266 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2267 GST_OBJECT_UNLOCK (element);
2272 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2273 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2275 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2276 "completed state change to %s", gst_element_state_get_name (pending));
2277 GST_OBJECT_UNLOCK (element);
2279 /* don't post silly messages with the same state. This can happen
2280 * when an element state is changed to what it already was. For bins
2281 * this can be the result of a lost state, which we check with the
2282 * previous return value.
2283 * We do signal the cond though as a _get_state() might be blocking
2285 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2286 _priv_gst_element_state_changed (element, old_state, old_next,
2287 GST_STATE_VOID_PENDING);
2289 GST_STATE_BROADCAST (element);
2296 * gst_element_lost_state:
2297 * @element: a #GstElement the state is lost of
2299 * Brings the element to the lost state. The current state of the
2300 * element is copied to the pending state so that any call to
2301 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2303 * An ASYNC_START message is posted. If the element was PLAYING, it will
2304 * go to PAUSED. The element will be restored to its PLAYING state by
2305 * the parent pipeline when it prerolls again.
2307 * This is mostly used for elements that lost their preroll buffer
2308 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2309 * they will go to their pending state again when a new preroll buffer is
2310 * queued. This function can only be called when the element is currently
2311 * not in error or an async state change.
2313 * This function is used internally and should normally not be called from
2314 * plugins or applications.
2317 gst_element_lost_state (GstElement * element)
2319 GstState old_state, new_state;
2320 GstMessage *message;
2322 g_return_if_fail (GST_IS_ELEMENT (element));
2324 GST_OBJECT_LOCK (element);
2325 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2328 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2329 goto only_async_start;
2331 old_state = GST_STATE (element);
2333 /* when we were PLAYING, the new state is PAUSED. We will also not
2334 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2335 * when we preroll. */
2336 if (old_state > GST_STATE_PAUSED)
2337 new_state = GST_STATE_PAUSED;
2339 new_state = old_state;
2341 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2342 "lost state of %s to %s", gst_element_state_get_name (old_state),
2343 gst_element_state_get_name (new_state));
2345 GST_STATE (element) = new_state;
2346 GST_STATE_NEXT (element) = new_state;
2347 GST_STATE_PENDING (element) = new_state;
2348 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2349 GST_OBJECT_UNLOCK (element);
2351 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2353 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2354 gst_element_post_message (element, message);
2360 GST_OBJECT_UNLOCK (element);
2365 GST_OBJECT_UNLOCK (element);
2367 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2368 gst_element_post_message (element, message);
2374 * gst_element_set_state:
2375 * @element: a #GstElement to change state of.
2376 * @state: the element's new #GstState.
2378 * Sets the state of the element. This function will try to set the
2379 * requested state by going through all the intermediary states and calling
2380 * the class's state change function for each.
2382 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2383 * element will perform the remainder of the state change asynchronously in
2385 * An application can use gst_element_get_state() to wait for the completion
2386 * of the state change or it can wait for a state change message on the bus.
2388 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2389 * #GST_STATE_CHANGE_ASYNC.
2391 * Returns: Result of the state change using #GstStateChangeReturn.
2395 GstStateChangeReturn
2396 gst_element_set_state (GstElement * element, GstState state)
2398 GstElementClass *oclass;
2399 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2401 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2403 oclass = GST_ELEMENT_GET_CLASS (element);
2405 if (oclass->set_state)
2406 result = (oclass->set_state) (element, state);
2412 * default set state function, calculates the next state based
2413 * on current state and calls the change_state function
2415 static GstStateChangeReturn
2416 gst_element_set_state_func (GstElement * element, GstState state)
2418 GstState current, next, old_pending;
2419 GstStateChangeReturn ret;
2420 GstStateChange transition;
2421 GstStateChangeReturn old_ret;
2423 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2425 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2426 gst_element_state_get_name (state));
2428 /* state lock is taken to protect the set_state() and get_state()
2429 * procedures, it does not lock any variables. */
2430 GST_STATE_LOCK (element);
2432 /* now calculate how to get to the new state */
2433 GST_OBJECT_LOCK (element);
2434 old_ret = GST_STATE_RETURN (element);
2435 /* previous state change returned an error, remove all pending
2436 * and next states */
2437 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2438 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2439 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2440 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2443 current = GST_STATE (element);
2444 next = GST_STATE_NEXT (element);
2445 old_pending = GST_STATE_PENDING (element);
2447 /* this is the (new) state we should go to. TARGET is the last state we set on
2449 if (state != GST_STATE_TARGET (element)) {
2450 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2451 "setting target state to %s", gst_element_state_get_name (state));
2452 GST_STATE_TARGET (element) = state;
2453 /* increment state cookie so that we can track each state change. We only do
2454 * this if this is actually a new state change. */
2455 element->state_cookie++;
2457 GST_STATE_PENDING (element) = state;
2459 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2460 "current %s, old_pending %s, next %s, old return %s",
2461 gst_element_state_get_name (current),
2462 gst_element_state_get_name (old_pending),
2463 gst_element_state_get_name (next),
2464 gst_element_state_change_return_get_name (old_ret));
2466 /* if the element was busy doing a state change, we just update the
2467 * target state, it'll get to it async then. */
2468 if (old_pending != GST_STATE_VOID_PENDING) {
2469 /* upwards state change will happen ASYNC */
2470 if (old_pending <= state)
2472 /* element is going to this state already */
2473 else if (next == state)
2475 /* element was performing an ASYNC upward state change and
2476 * we request to go downward again. Start from the next pending
2478 else if (next > state
2479 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2483 next = GST_STATE_GET_NEXT (current, state);
2484 /* now we store the next state */
2485 GST_STATE_NEXT (element) = next;
2486 /* mark busy, we need to check that there is actually a state change
2487 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2488 * the default element change_state function has no way to know what the
2489 * old value was... could consider this a FIXME...*/
2490 if (current != next)
2491 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2493 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2495 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2496 "%s: setting state from %s to %s",
2497 (next != state ? "intermediate" : "final"),
2498 gst_element_state_get_name (current), gst_element_state_get_name (next));
2500 /* now signal any waiters, they will error since the cookie was incremented */
2501 GST_STATE_BROADCAST (element);
2503 GST_OBJECT_UNLOCK (element);
2505 ret = gst_element_change_state (element, transition);
2507 GST_STATE_UNLOCK (element);
2509 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2510 gst_element_state_change_return_get_name (ret));
2516 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2517 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2518 "element was busy with async state change");
2519 GST_OBJECT_UNLOCK (element);
2521 GST_STATE_UNLOCK (element);
2523 return GST_STATE_CHANGE_ASYNC;
2528 * gst_element_change_state:
2529 * @element: a #GstElement
2530 * @transition: the requested transition
2532 * Perform @transition on @element.
2534 * This function must be called with STATE_LOCK held and is mainly used
2537 * Returns: the #GstStateChangeReturn of the state transition.
2539 GstStateChangeReturn
2540 gst_element_change_state (GstElement * element, GstStateChange transition)
2542 GstElementClass *oclass;
2543 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2545 oclass = GST_ELEMENT_GET_CLASS (element);
2547 /* call the state change function so it can set the state */
2548 if (oclass->change_state)
2549 ret = (oclass->change_state) (element, transition);
2551 ret = GST_STATE_CHANGE_FAILURE;
2554 case GST_STATE_CHANGE_FAILURE:
2555 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2556 "have FAILURE change_state return");
2557 /* state change failure */
2558 gst_element_abort_state (element);
2560 case GST_STATE_CHANGE_ASYNC:
2564 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2565 "element will change state ASYNC");
2567 target = GST_STATE_TARGET (element);
2569 if (target > GST_STATE_READY)
2572 /* else we just continue the state change downwards */
2573 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2574 "forcing commit state %s <= %s",
2575 gst_element_state_get_name (target),
2576 gst_element_state_get_name (GST_STATE_READY));
2578 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2581 case GST_STATE_CHANGE_SUCCESS:
2582 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2583 "element changed state SUCCESS");
2584 /* we can commit the state now which will proceeed to
2586 ret = gst_element_continue_state (element, ret);
2588 case GST_STATE_CHANGE_NO_PREROLL:
2589 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2590 "element changed state NO_PREROLL");
2591 /* we can commit the state now which will proceeed to
2593 ret = gst_element_continue_state (element, ret);
2596 goto invalid_return;
2599 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2604 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2612 GST_OBJECT_LOCK (element);
2613 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2614 g_critical ("%s: unknown return value %d from a state change function",
2615 GST_ELEMENT_NAME (element), ret);
2617 /* we are in error now */
2618 ret = GST_STATE_CHANGE_FAILURE;
2619 GST_STATE_RETURN (element) = ret;
2620 GST_OBJECT_UNLOCK (element);
2626 /* gst_iterator_fold functions for pads_activate
2627 * Stop the iterator if activating one pad failed. */
2629 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2631 GstPad *pad = g_value_get_object (vpad);
2632 gboolean cont = TRUE;
2634 if (!(cont = gst_pad_set_active (pad, *active)))
2635 g_value_set_boolean (ret, FALSE);
2640 /* returns false on error or early cutout of the fold, true if all
2641 * pads in @iter were (de)activated successfully. */
2643 iterator_activate_fold_with_resync (GstIterator * iter,
2644 GstIteratorFoldFunction func, gpointer user_data)
2646 GstIteratorResult ires;
2649 /* no need to unset this later, it's just a boolean */
2650 g_value_init (&ret, G_TYPE_BOOLEAN);
2651 g_value_set_boolean (&ret, TRUE);
2654 ires = gst_iterator_fold (iter, func, &ret, user_data);
2656 case GST_ITERATOR_RESYNC:
2657 /* need to reset the result again */
2658 g_value_set_boolean (&ret, TRUE);
2659 gst_iterator_resync (iter);
2661 case GST_ITERATOR_DONE:
2662 /* all pads iterated, return collected value */
2665 /* iterator returned _ERROR or premature end with _OK,
2666 * mark an error and exit */
2667 g_value_set_boolean (&ret, FALSE);
2672 /* return collected value */
2673 return g_value_get_boolean (&ret);
2676 /* is called with STATE_LOCK
2678 * Pads are activated from source pads to sinkpads.
2681 gst_element_pads_activate (GstElement * element, gboolean active)
2686 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2687 "pads_activate with active %d", active);
2689 iter = gst_element_iterate_src_pads (element);
2691 iterator_activate_fold_with_resync (iter,
2692 (GstIteratorFoldFunction) activate_pads, &active);
2693 gst_iterator_free (iter);
2694 if (G_UNLIKELY (!res))
2697 iter = gst_element_iterate_sink_pads (element);
2699 iterator_activate_fold_with_resync (iter,
2700 (GstIteratorFoldFunction) activate_pads, &active);
2701 gst_iterator_free (iter);
2702 if (G_UNLIKELY (!res))
2705 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2706 "pads_activate successful");
2713 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2714 "source pads_activate failed");
2719 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2720 "sink pads_activate failed");
2725 /* is called with STATE_LOCK */
2726 static GstStateChangeReturn
2727 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2729 GstState state, next;
2730 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2732 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2734 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2735 next = GST_STATE_TRANSITION_NEXT (transition);
2737 /* if the element already is in the given state, we just return success */
2738 if (next == GST_STATE_VOID_PENDING || state == next)
2741 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2742 "default handler tries setting state from %s to %s (%04x)",
2743 gst_element_state_get_name (state),
2744 gst_element_state_get_name (next), transition);
2746 switch (transition) {
2747 case GST_STATE_CHANGE_NULL_TO_READY:
2749 case GST_STATE_CHANGE_READY_TO_PAUSED:
2750 if (!gst_element_pads_activate (element, TRUE)) {
2751 result = GST_STATE_CHANGE_FAILURE;
2754 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2756 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2758 case GST_STATE_CHANGE_PAUSED_TO_READY:
2759 case GST_STATE_CHANGE_READY_TO_NULL:
2760 /* deactivate pads in both cases, since they are activated on
2761 ready->paused but the element might not have made it to paused */
2762 if (!gst_element_pads_activate (element, FALSE)) {
2763 result = GST_STATE_CHANGE_FAILURE;
2767 /* this will catch real but unhandled state changes;
2768 * can only be caused by:
2769 * - a new state was added
2770 * - somehow the element was asked to jump across an intermediate state
2772 g_warning ("Unhandled state change from %s to %s",
2773 gst_element_state_get_name (state),
2774 gst_element_state_get_name (next));
2781 GST_OBJECT_LOCK (element);
2782 result = GST_STATE_RETURN (element);
2783 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2784 "element is already in the %s state",
2785 gst_element_state_get_name (state));
2786 GST_OBJECT_UNLOCK (element);
2793 * gst_element_get_factory:
2794 * @element: a #GstElement to request the element factory of.
2796 * Retrieves the factory that was used to create this element.
2798 * Returns: (transfer none): the #GstElementFactory used for creating this
2799 * element. no refcounting is needed.
2802 gst_element_get_factory (GstElement * element)
2804 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2806 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2810 gst_element_dispose (GObject * object)
2812 GstElement *element = GST_ELEMENT_CAST (object);
2816 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2818 if (GST_STATE (element) != GST_STATE_NULL)
2821 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2822 "removing %d pads", g_list_length (element->pads));
2823 /* first we break all our links with the outside */
2824 while (element->pads && element->pads->data) {
2825 /* don't call _remove_pad with NULL */
2826 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2828 if (G_UNLIKELY (element->pads != NULL)) {
2829 g_critical ("could not remove pads from element %s",
2830 GST_STR_NULL (GST_OBJECT_NAME (object)));
2833 GST_OBJECT_LOCK (element);
2834 clock_p = &element->clock;
2835 bus_p = &element->bus;
2836 gst_object_replace ((GstObject **) clock_p, NULL);
2837 gst_object_replace ((GstObject **) bus_p, NULL);
2838 GST_OBJECT_UNLOCK (element);
2840 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2842 G_OBJECT_CLASS (parent_class)->dispose (object);
2851 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2853 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2855 "You need to explicitly set elements to the NULL state before\n"
2856 "dropping the final reference, to allow them to clean up.\n"
2857 "This problem may also be caused by a refcounting bug in the\n"
2858 "application or some element.\n",
2859 GST_OBJECT_NAME (element),
2860 gst_element_state_get_name (GST_STATE (element)),
2861 is_locked ? " (locked)" : "");
2867 gst_element_finalize (GObject * object)
2869 GstElement *element = GST_ELEMENT_CAST (object);
2871 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2873 g_cond_free (element->state_cond);
2874 g_static_rec_mutex_free (&element->state_lock);
2876 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2878 G_OBJECT_CLASS (parent_class)->finalize (object);
2882 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2886 g_return_if_fail (GST_IS_ELEMENT (element));
2888 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2890 GST_OBJECT_LOCK (element);
2891 bus_p = &GST_ELEMENT_BUS (element);
2892 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2893 GST_OBJECT_UNLOCK (element);
2897 * gst_element_set_bus:
2898 * @element: a #GstElement to set the bus of.
2899 * @bus: (transfer none): the #GstBus to set.
2901 * Sets the bus of the element. Increases the refcount on the bus.
2902 * For internal use only, unless you're testing elements.
2907 gst_element_set_bus (GstElement * element, GstBus * bus)
2909 GstElementClass *oclass;
2911 g_return_if_fail (GST_IS_ELEMENT (element));
2913 oclass = GST_ELEMENT_GET_CLASS (element);
2915 if (oclass->set_bus)
2916 oclass->set_bus (element, bus);
2920 * gst_element_get_bus:
2921 * @element: a #GstElement to get the bus of.
2923 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2924 * bus for the application.
2926 * Returns: (transfer full): the element's #GstBus. unref after usage.
2931 gst_element_get_bus (GstElement * element)
2933 GstBus *result = NULL;
2935 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2937 GST_OBJECT_LOCK (element);
2938 if ((result = GST_ELEMENT_BUS (element)))
2939 gst_object_ref (result);
2940 GST_OBJECT_UNLOCK (element);
2942 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,