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 gboolean gst_element_set_clock_func (GstElement * element,
131 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
133 static gboolean gst_element_default_send_event (GstElement * element,
135 static gboolean gst_element_default_query (GstElement * element,
138 static GstPadTemplate
139 * gst_element_class_get_request_pad_template (GstElementClass *
140 element_class, const gchar * name);
142 static GstObjectClass *parent_class = NULL;
143 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
145 /* this is used in gstelementfactory.c:gst_element_register() */
146 GQuark __gst_elementclass_factory = 0;
149 gst_element_get_type (void)
151 static volatile gsize gst_element_type = 0;
153 if (g_once_init_enter (&gst_element_type)) {
155 static const GTypeInfo element_info = {
156 sizeof (GstElementClass),
157 gst_element_base_class_init,
158 gst_element_base_class_finalize,
159 (GClassInitFunc) gst_element_class_init,
164 (GInstanceInitFunc) gst_element_init,
168 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
169 &element_info, G_TYPE_FLAG_ABSTRACT);
171 __gst_elementclass_factory =
172 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
173 g_once_init_leave (&gst_element_type, _type);
175 return gst_element_type;
179 gst_element_class_init (GstElementClass * klass)
181 GObjectClass *gobject_class;
183 gobject_class = (GObjectClass *) klass;
185 parent_class = g_type_class_peek_parent (klass);
188 * GstElement::pad-added:
189 * @gstelement: the object which received the signal
190 * @new_pad: the pad that has been added
192 * a new #GstPad has been added to the element. Note that this signal will
193 * usually be emitted from the context of the streaming thread. Also keep in
194 * mind that if you add new elements to the pipeline in the signal handler
195 * you will need to set them to the desired target state with
196 * gst_element_set_state() or gst_element_sync_state_with_parent().
198 gst_element_signals[PAD_ADDED] =
199 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
200 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
201 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
203 * GstElement::pad-removed:
204 * @gstelement: the object which received the signal
205 * @old_pad: the pad that has been removed
207 * a #GstPad has been removed from the element
209 gst_element_signals[PAD_REMOVED] =
210 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
211 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
212 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
214 * GstElement::no-more-pads:
215 * @gstelement: the object which received the signal
217 * This signals that the element will not generate more dynamic pads.
218 * Note that this signal will usually be emitted from the context of
219 * the streaming thread.
221 gst_element_signals[NO_MORE_PADS] =
222 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
223 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
224 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
226 gobject_class->dispose = gst_element_dispose;
227 gobject_class->finalize = gst_element_finalize;
229 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
230 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
231 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
232 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
233 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
234 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
235 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
236 klass->numpadtemplates = 0;
238 klass->elementfactory = NULL;
242 gst_element_base_class_init (gpointer g_class)
244 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
245 GList *node, *padtemplates;
247 /* Copy the element details here so elements can inherit the
248 * details from their base class and classes only need to set
249 * the details in class_init instead of base_init */
250 element_class->metadata =
251 element_class->metadata ? gst_structure_copy (element_class->metadata) :
252 gst_structure_new_empty ("metadata");
254 /* Copy the pad templates so elements inherit them
255 * from their base class but elements can add pad templates in class_init
256 * instead of base_init.
258 padtemplates = g_list_copy (element_class->padtemplates);
259 for (node = padtemplates; node != NULL; node = node->next) {
260 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
261 gst_object_ref (tmpl);
263 element_class->padtemplates = padtemplates;
265 /* set the factory, see gst_element_register() */
266 element_class->elementfactory =
267 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
268 __gst_elementclass_factory);
269 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
270 element_class->elementfactory);
274 gst_element_base_class_finalize (gpointer g_class)
276 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
278 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
279 g_list_free (klass->padtemplates);
281 gst_structure_free (klass->metadata);
285 gst_element_init (GstElement * element)
287 GST_STATE (element) = GST_STATE_NULL;
288 GST_STATE_TARGET (element) = GST_STATE_NULL;
289 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
290 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
291 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
293 g_static_rec_mutex_init (&element->state_lock);
294 element->state_cond = g_cond_new ();
298 * gst_element_release_request_pad:
299 * @element: a #GstElement to release the request pad of.
300 * @pad: the #GstPad to release.
302 * Makes the element free the previously requested pad as obtained
303 * with gst_element_get_request_pad().
305 * This does not unref the pad. If the pad was created by using
306 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
307 * followed by gst_object_unref() to free the @pad.
312 gst_element_release_request_pad (GstElement * element, GstPad * pad)
314 GstElementClass *oclass;
316 g_return_if_fail (GST_IS_ELEMENT (element));
317 g_return_if_fail (GST_IS_PAD (pad));
319 oclass = GST_ELEMENT_GET_CLASS (element);
321 /* if the element implements a custom release function we call that, else we
322 * simply remove the pad from the element */
323 if (oclass->release_pad)
324 (oclass->release_pad) (element, pad);
326 gst_element_remove_pad (element, pad);
330 * gst_element_requires_clock:
331 * @element: a #GstElement to query
333 * Query if the element requires a clock.
335 * Returns: %TRUE if the element requires a clock
340 gst_element_requires_clock (GstElement * element)
344 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
346 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
352 * gst_element_provides_clock:
353 * @element: a #GstElement to query
355 * Query if the element provides a clock. A #GstClock provided by an
356 * element can be used as the global #GstClock for the pipeline.
357 * An element that can provide a clock is only required to do so in the PAUSED
358 * state, this means when it is fully negotiated and has allocated the resources
359 * to operate the clock.
361 * Returns: %TRUE if the element provides a clock
366 gst_element_provides_clock (GstElement * element)
370 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
372 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
378 * gst_element_provide_clock:
379 * @element: a #GstElement to query
381 * Get the clock provided by the given element.
382 * <note>An element is only required to provide a clock in the PAUSED
383 * state. Some elements can provide a clock in other states.</note>
385 * Returns: (transfer full): the GstClock provided by the element or %NULL
386 * if no clock could be provided. Unref after usage.
391 gst_element_provide_clock (GstElement * element)
393 GstClock *result = NULL;
394 GstElementClass *oclass;
396 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
398 oclass = GST_ELEMENT_GET_CLASS (element);
400 if (oclass->provide_clock)
401 result = oclass->provide_clock (element);
407 gst_element_set_clock_func (GstElement * element, GstClock * clock)
411 GST_OBJECT_LOCK (element);
412 clock_p = &element->clock;
413 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
414 GST_OBJECT_UNLOCK (element);
420 * gst_element_set_clock:
421 * @element: a #GstElement to set the clock for.
422 * @clock: the #GstClock to set for the element.
424 * Sets the clock for the element. This function increases the
425 * refcount on the clock. Any previously set clock on the object
428 * Returns: %TRUE if the element accepted the clock. An element can refuse a
429 * clock when it, for example, is not able to slave its internal clock to the
430 * @clock or when it requires a specific clock to operate.
435 gst_element_set_clock (GstElement * element, GstClock * clock)
437 GstElementClass *oclass;
438 gboolean res = FALSE;
440 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
441 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
443 oclass = GST_ELEMENT_GET_CLASS (element);
445 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
447 if (oclass->set_clock)
448 res = oclass->set_clock (element, clock);
454 * gst_element_get_clock:
455 * @element: a #GstElement to get the clock of.
457 * Gets the currently configured clock of the element. This is the clock as was
458 * last set with gst_element_set_clock().
460 * Returns: (transfer full): the #GstClock of the element. unref after usage.
465 gst_element_get_clock (GstElement * element)
469 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
471 GST_OBJECT_LOCK (element);
472 if ((result = element->clock))
473 gst_object_ref (result);
474 GST_OBJECT_UNLOCK (element);
480 * gst_element_set_base_time:
481 * @element: a #GstElement.
482 * @time: the base time to set.
484 * Set the base time of an element. See gst_element_get_base_time().
489 gst_element_set_base_time (GstElement * element, GstClockTime time)
493 g_return_if_fail (GST_IS_ELEMENT (element));
495 GST_OBJECT_LOCK (element);
496 old = element->base_time;
497 element->base_time = time;
498 GST_OBJECT_UNLOCK (element);
500 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
501 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
502 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
506 * gst_element_get_base_time:
507 * @element: a #GstElement.
509 * Returns the base time of the element. The base time is the
510 * absolute time of the clock when this element was last put to
511 * PLAYING. Subtracting the base time from the clock time gives
512 * the running time of the element.
514 * Returns: the base time of the element.
519 gst_element_get_base_time (GstElement * element)
523 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
525 GST_OBJECT_LOCK (element);
526 result = element->base_time;
527 GST_OBJECT_UNLOCK (element);
533 * gst_element_set_start_time:
534 * @element: a #GstElement.
535 * @time: the base time to set.
537 * Set the start time of an element. The start time of the element is the
538 * running time of the element when it last went to the PAUSED state. In READY
539 * or after a flushing seek, it is set to 0.
541 * Toplevel elements like #GstPipeline will manage the start_time and
542 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
543 * on such a toplevel element will disable the distribution of the base_time to
544 * the children and can be useful if the application manages the base_time
545 * itself, for example if you want to synchronize capture from multiple
546 * pipelines, and you can also ensure that the pipelines have the same clock.
553 gst_element_set_start_time (GstElement * element, GstClockTime time)
557 g_return_if_fail (GST_IS_ELEMENT (element));
559 GST_OBJECT_LOCK (element);
560 old = GST_ELEMENT_START_TIME (element);
561 GST_ELEMENT_START_TIME (element) = time;
562 GST_OBJECT_UNLOCK (element);
564 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
565 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
566 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
570 * gst_element_get_start_time:
571 * @element: a #GstElement.
573 * Returns the start time of the element. The start time is the
574 * running time of the clock when this element was last put to PAUSED.
576 * Usually the start_time is managed by a toplevel element such as
581 * Returns: the start time of the element.
586 gst_element_get_start_time (GstElement * element)
590 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
592 GST_OBJECT_LOCK (element);
593 result = GST_ELEMENT_START_TIME (element);
594 GST_OBJECT_UNLOCK (element);
600 * gst_element_is_indexable:
601 * @element: a #GstElement.
603 * Queries if the element can be indexed.
605 * Returns: TRUE if the element can be indexed.
610 gst_element_is_indexable (GstElement * element)
614 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
616 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
622 * gst_element_set_index:
623 * @element: a #GstElement.
624 * @index: (transfer none): a #GstIndex.
626 * Set @index on the element. The refcount of the index
627 * will be increased, any previously set index is unreffed.
632 gst_element_set_index (GstElement * element, GstIndex * index)
634 GstElementClass *oclass;
636 g_return_if_fail (GST_IS_ELEMENT (element));
637 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
639 oclass = GST_ELEMENT_GET_CLASS (element);
641 if (oclass->set_index)
642 oclass->set_index (element, index);
646 * gst_element_get_index:
647 * @element: a #GstElement.
649 * Gets the index from the element.
651 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
652 * element. unref after usage.
657 gst_element_get_index (GstElement * element)
659 GstElementClass *oclass;
660 GstIndex *result = NULL;
662 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
664 oclass = GST_ELEMENT_GET_CLASS (element);
666 if (oclass->get_index)
667 result = oclass->get_index (element);
673 * gst_element_add_pad:
674 * @element: a #GstElement to add the pad to.
675 * @pad: (transfer full): the #GstPad to add to the element.
677 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
678 * see gst_object_set_parent() for refcounting information.
680 * Pads are not automatically activated so elements should perform the needed
681 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
682 * state. See gst_pad_set_active() for more information about activating pads.
684 * The pad and the element should be unlocked when calling this function.
686 * This function will emit the #GstElement::pad-added signal on the element.
688 * Returns: %TRUE if the pad could be added. This function can fail when
689 * a pad with the same name already existed or the pad already had another
695 gst_element_add_pad (GstElement * element, GstPad * pad)
700 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
701 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
703 /* locking pad to look at the name */
704 GST_OBJECT_LOCK (pad);
705 pad_name = g_strdup (GST_PAD_NAME (pad));
706 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
707 GST_STR_NULL (pad_name));
708 flushing = GST_PAD_IS_FLUSHING (pad);
709 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
710 GST_OBJECT_UNLOCK (pad);
712 /* then check to see if there's already a pad by that name here */
713 GST_OBJECT_LOCK (element);
714 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
717 /* try to set the pad's parent */
718 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
719 GST_OBJECT_CAST (element))))
722 /* check for flushing pads */
723 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
724 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
725 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
726 "use gst_pad_set_active(pad,TRUE) before adding it.",
727 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
729 GST_OBJECT_LOCK (pad);
730 GST_PAD_UNSET_FLUSHING (pad);
731 GST_OBJECT_UNLOCK (pad);
736 /* add it to the list */
737 switch (gst_pad_get_direction (pad)) {
739 element->srcpads = g_list_prepend (element->srcpads, pad);
740 element->numsrcpads++;
743 element->sinkpads = g_list_prepend (element->sinkpads, pad);
744 element->numsinkpads++;
749 element->pads = g_list_prepend (element->pads, pad);
751 element->pads_cookie++;
752 GST_OBJECT_UNLOCK (element);
754 /* emit the PAD_ADDED signal */
755 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
762 g_critical ("Padname %s is not unique in element %s, not adding",
763 pad_name, GST_ELEMENT_NAME (element));
764 GST_OBJECT_UNLOCK (element);
771 ("Pad %s already has parent when trying to add to element %s",
772 pad_name, GST_ELEMENT_NAME (element));
773 GST_OBJECT_UNLOCK (element);
779 GST_OBJECT_LOCK (pad);
781 ("Trying to add pad %s to element %s, but it has no direction",
782 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
783 GST_OBJECT_UNLOCK (pad);
784 GST_OBJECT_UNLOCK (element);
790 * gst_element_remove_pad:
791 * @element: a #GstElement to remove pad from.
792 * @pad: (transfer none): the #GstPad to remove from the element.
794 * Removes @pad from @element. @pad will be destroyed if it has not been
795 * referenced elsewhere using gst_object_unparent().
797 * This function is used by plugin developers and should not be used
798 * by applications. Pads that were dynamically requested from elements
799 * with gst_element_get_request_pad() should be released with the
800 * gst_element_release_request_pad() function instead.
802 * Pads are not automatically deactivated so elements should perform the needed
803 * steps to deactivate the pad in case this pad is removed in the PAUSED or
804 * PLAYING state. See gst_pad_set_active() for more information about
807 * The pad and the element should be unlocked when calling this function.
809 * This function will emit the #GstElement::pad-removed signal on the element.
811 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
812 * pad does not belong to the provided element.
817 gst_element_remove_pad (GstElement * element, GstPad * pad)
821 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
822 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
824 /* locking pad to look at the name and parent */
825 GST_OBJECT_LOCK (pad);
826 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
827 GST_STR_NULL (GST_PAD_NAME (pad)));
829 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
831 GST_OBJECT_UNLOCK (pad);
834 if ((peer = gst_pad_get_peer (pad))) {
835 /* window for MT unsafeness, someone else could unlink here
836 * and then we call unlink with wrong pads. The unlink
837 * function would catch this and safely return failed. */
838 if (GST_PAD_IS_SRC (pad))
839 gst_pad_unlink (pad, peer);
841 gst_pad_unlink (peer, pad);
843 gst_object_unref (peer);
846 GST_OBJECT_LOCK (element);
847 /* remove it from the list */
848 switch (gst_pad_get_direction (pad)) {
850 element->srcpads = g_list_remove (element->srcpads, pad);
851 element->numsrcpads--;
854 element->sinkpads = g_list_remove (element->sinkpads, pad);
855 element->numsinkpads--;
858 g_critical ("Removing pad without direction???");
861 element->pads = g_list_remove (element->pads, pad);
863 element->pads_cookie++;
864 GST_OBJECT_UNLOCK (element);
866 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
867 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
869 gst_object_unparent (GST_OBJECT_CAST (pad));
876 /* locking order is element > pad */
877 GST_OBJECT_UNLOCK (pad);
879 GST_OBJECT_LOCK (element);
880 GST_OBJECT_LOCK (pad);
881 g_critical ("Padname %s:%s does not belong to element %s when removing",
882 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
883 GST_OBJECT_UNLOCK (pad);
884 GST_OBJECT_UNLOCK (element);
890 * gst_element_no_more_pads:
891 * @element: a #GstElement
893 * Use this function to signal that the element does not expect any more pads
894 * to show up in the current pipeline. This function should be called whenever
895 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
896 * pad templates use this in combination with autopluggers to figure out that
897 * the element is done initializing its pads.
899 * This function emits the #GstElement::no-more-pads signal.
904 gst_element_no_more_pads (GstElement * element)
906 g_return_if_fail (GST_IS_ELEMENT (element));
908 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
912 pad_compare_name (GstPad * pad1, const gchar * name)
916 GST_OBJECT_LOCK (pad1);
917 result = strcmp (GST_PAD_NAME (pad1), name);
918 GST_OBJECT_UNLOCK (pad1);
924 * gst_element_get_static_pad:
925 * @element: a #GstElement to find a static pad of.
926 * @name: the name of the static #GstPad to retrieve.
928 * Retrieves a pad from @element by name. This version only retrieves
929 * already-existing (i.e. 'static') pads.
931 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
937 gst_element_get_static_pad (GstElement * element, const gchar * name)
940 GstPad *result = NULL;
942 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
943 g_return_val_if_fail (name != NULL, NULL);
945 GST_OBJECT_LOCK (element);
947 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
949 result = GST_PAD_CAST (find->data);
950 gst_object_ref (result);
953 if (result == NULL) {
954 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
955 name, GST_ELEMENT_NAME (element));
957 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
958 GST_ELEMENT_NAME (element), name);
960 GST_OBJECT_UNLOCK (element);
966 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
967 const gchar * name, const GstCaps * caps)
969 GstPad *newpad = NULL;
970 GstElementClass *oclass;
972 oclass = GST_ELEMENT_GET_CLASS (element);
974 #ifndef G_DISABLE_CHECKS
975 /* Some sanity checking here */
979 /* Is this the template name? */
980 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
981 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
983 const gchar *str, *data;
986 /* Otherwise check if it's a valid name for the name template */
987 str = strchr (templ->name_template, '%');
988 g_return_val_if_fail (str != NULL, NULL);
989 g_return_val_if_fail (strncmp (templ->name_template, name,
990 str - templ->name_template) == 0, NULL);
991 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
993 data = name + (str - templ->name_template);
995 /* Can either be %s or %d or %u, do sanity checking for %d */
996 if (*(str + 1) == 'd') {
1000 tmp = g_ascii_strtoll (data, &endptr, 10);
1001 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
1002 && *endptr == '\0', NULL);
1003 } else if (*(str + 1) == 'u') {
1007 tmp = g_ascii_strtoull (data, &endptr, 10);
1008 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
1012 pad = gst_element_get_static_pad (element, name);
1014 gst_object_unref (pad);
1015 /* FIXME 0.11: Change this to g_return_val_if_fail() */
1016 g_critical ("Element %s already has a pad named %s, the behaviour of "
1017 " gst_element_get_request_pad() for existing pads is undefined!",
1018 GST_ELEMENT_NAME (element), name);
1023 if (oclass->request_new_pad)
1024 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1027 gst_object_ref (newpad);
1033 * gst_element_get_request_pad:
1034 * @element: a #GstElement to find a request pad of.
1035 * @name: the name of the request #GstPad to retrieve.
1037 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1038 * retrieves request pads. The pad should be released with
1039 * gst_element_release_request_pad().
1041 * This method is slow and will be deprecated in the future. New code should
1042 * use gst_element_request_pad() with the requested template.
1044 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1045 * Release after usage.
1048 gst_element_get_request_pad (GstElement * element, const gchar * name)
1050 GstPadTemplate *templ = NULL;
1052 const gchar *req_name = NULL;
1053 gboolean templ_found = FALSE;
1056 gchar *str, *endptr = NULL;
1057 GstElementClass *class;
1059 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1060 g_return_val_if_fail (name != NULL, NULL);
1062 class = GST_ELEMENT_GET_CLASS (element);
1064 /* if the name contains a %, we assume it's the complete template name. Get
1065 * the template and try to get a pad */
1066 if (strstr (name, "%")) {
1067 templ = gst_element_class_get_request_pad_template (class, name);
1072 /* there is no % in the name, try to find a matching template */
1073 list = class->padtemplates;
1074 while (!templ_found && list) {
1075 templ = (GstPadTemplate *) list->data;
1076 if (templ->presence == GST_PAD_REQUEST) {
1077 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1078 templ->name_template);
1079 /* see if we find an exact match */
1080 if (strcmp (name, templ->name_template) == 0) {
1085 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1086 and %d and %u, occurring at the end of the name_template, are the only
1088 else if ((str = strchr (templ->name_template, '%'))
1089 && strncmp (templ->name_template, name,
1090 str - templ->name_template) == 0
1091 && strlen (name) > str - templ->name_template) {
1092 data = name + (str - templ->name_template);
1093 if (*(str + 1) == 'd') {
1097 tmp = strtol (data, &endptr, 10);
1098 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1104 } else if (*(str + 1) == 'u') {
1108 tmp = strtoul (data, &endptr, 10);
1109 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1129 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1135 * gst_element_request_pad:
1136 * @element: a #GstElement to find a request pad of.
1137 * @templ: a #GstPadTemplate of which we want a pad of.
1138 * @name: (transfer none) (allow-none): the name of the request #GstPad
1139 * to retrieve. Can be %NULL.
1140 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1141 * request. Can be %NULL.
1143 * Retrieves a request pad from the element according to the provided template.
1144 * Pad templates can be looked up using
1145 * gst_element_factory_get_static_pad_templates().
1147 * The pad should be released with gst_element_release_request_pad().
1149 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1150 * Release after usage.
1155 gst_element_request_pad (GstElement * element,
1156 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1158 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1159 g_return_val_if_fail (templ != NULL, NULL);
1161 return _gst_element_request_pad (element, templ, name, caps);
1164 static GstIterator *
1165 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1167 GstIterator *result;
1169 GST_OBJECT_LOCK (element);
1170 result = gst_iterator_new_list (GST_TYPE_PAD,
1171 GST_OBJECT_GET_LOCK (element),
1172 &element->pads_cookie, padlist, (GObject *) element, NULL);
1173 GST_OBJECT_UNLOCK (element);
1179 * gst_element_iterate_pads:
1180 * @element: a #GstElement to iterate pads of.
1182 * Retrieves an iterator of @element's pads. The iterator should
1183 * be freed after usage. Also more specialized iterators exists such as
1184 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1186 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1192 gst_element_iterate_pads (GstElement * element)
1194 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1196 return gst_element_iterate_pad_list (element, &element->pads);
1200 * gst_element_iterate_src_pads:
1201 * @element: a #GstElement.
1203 * Retrieves an iterator of @element's source pads.
1205 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1211 gst_element_iterate_src_pads (GstElement * element)
1213 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1215 return gst_element_iterate_pad_list (element, &element->srcpads);
1219 * gst_element_iterate_sink_pads:
1220 * @element: a #GstElement.
1222 * Retrieves an iterator of @element's sink pads.
1224 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1230 gst_element_iterate_sink_pads (GstElement * element)
1232 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1234 return gst_element_iterate_pad_list (element, &element->sinkpads);
1238 * gst_element_class_add_pad_template:
1239 * @klass: the #GstElementClass to add the pad template to.
1240 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1242 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1243 * functions of classes. If a pad template with the same name as an already
1244 * existing one is added the old one is replaced by the new one.
1248 gst_element_class_add_pad_template (GstElementClass * klass,
1249 GstPadTemplate * templ)
1251 GList *template_list = klass->padtemplates;
1253 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1254 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1256 /* If we already have a pad template with the same name replace the
1258 while (template_list) {
1259 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1261 /* Found pad with the same name, replace and return */
1262 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1263 gst_object_unref (padtempl);
1264 template_list->data = templ;
1267 template_list = g_list_next (template_list);
1270 /* Take ownership of the floating ref */
1271 gst_object_ref_sink (templ);
1273 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1274 klass->numpadtemplates++;
1278 * gst_element_class_add_metadata:
1279 * @klass: class to set metadata for
1280 * @key: the key to set
1281 * @value: the value to set
1283 * Set @key with @value as metadata in @klass.
1286 gst_element_class_add_metadata (GstElementClass * klass,
1287 const gchar * key, const gchar * value)
1289 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1290 g_return_if_fail (key != NULL);
1291 g_return_if_fail (value != NULL);
1293 gst_structure_set ((GstStructure *) klass->metadata,
1294 key, G_TYPE_STRING, value, NULL);
1298 * gst_element_class_set_metadata:
1299 * @klass: class to set metadata for
1300 * @longname: The long English name of the element. E.g. "File Sink"
1301 * @classification: String describing the type of element, as an unordered list
1302 * separated with slashes ('/'). See draft-klass.txt of the design docs
1303 * for more details and common types. E.g: "Sink/File"
1304 * @description: Sentence describing the purpose of the element.
1305 * E.g: "Write stream to a file"
1306 * @author: Name and contact details of the author(s). Use \n to separate
1307 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1309 * Sets the detailed information for a #GstElementClass.
1310 * <note>This function is for use in _class_init functions only.</note>
1313 gst_element_class_set_metadata (GstElementClass * klass,
1314 const gchar * longname, const gchar * classification,
1315 const gchar * description, const gchar * author)
1317 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1319 gst_structure_set ((GstStructure *) klass->metadata,
1320 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1321 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1322 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1323 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1327 * gst_element_class_get_metadata:
1328 * @klass: class to get metadata for
1329 * @key: the key to get
1331 * Get metadata with @key in @klass.
1333 * Returns: the metadata for @key.
1336 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1338 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1339 g_return_val_if_fail (key != NULL, NULL);
1341 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1345 * gst_element_class_get_pad_template_list:
1346 * @element_class: a #GstElementClass to get pad templates of.
1348 * Retrieves a list of the pad templates associated with @element_class. The
1349 * list must not be modified by the calling code.
1350 * <note>If you use this function in the #GInstanceInitFunc of an object class
1351 * that has subclasses, make sure to pass the g_class parameter of the
1352 * #GInstanceInitFunc here.</note>
1354 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1358 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1360 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1362 return element_class->padtemplates;
1366 * gst_element_class_get_pad_template:
1367 * @element_class: a #GstElementClass to get the pad template of.
1368 * @name: the name of the #GstPadTemplate to get.
1370 * Retrieves a padtemplate from @element_class with the given name.
1371 * <note>If you use this function in the #GInstanceInitFunc of an object class
1372 * that has subclasses, make sure to pass the g_class parameter of the
1373 * #GInstanceInitFunc here.</note>
1375 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1376 * if none was found. No unreferencing is necessary.
1379 gst_element_class_get_pad_template (GstElementClass *
1380 element_class, const gchar * name)
1384 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1385 g_return_val_if_fail (name != NULL, NULL);
1387 padlist = element_class->padtemplates;
1390 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1392 if (strcmp (padtempl->name_template, name) == 0)
1395 padlist = g_list_next (padlist);
1401 static GstPadTemplate *
1402 gst_element_class_get_request_pad_template (GstElementClass *
1403 element_class, const gchar * name)
1405 GstPadTemplate *tmpl;
1407 tmpl = gst_element_class_get_pad_template (element_class, name);
1408 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1414 /* get a random pad on element of the given direction.
1415 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1418 gst_element_get_random_pad (GstElement * element,
1419 gboolean need_linked, GstPadDirection dir)
1421 GstPad *result = NULL;
1424 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1428 GST_OBJECT_LOCK (element);
1429 pads = element->srcpads;
1432 GST_OBJECT_LOCK (element);
1433 pads = element->sinkpads;
1436 goto wrong_direction;
1438 for (; pads; pads = g_list_next (pads)) {
1439 GstPad *pad = GST_PAD_CAST (pads->data);
1441 GST_OBJECT_LOCK (pad);
1442 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1443 GST_DEBUG_PAD_NAME (pad));
1445 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1446 /* if we require a linked pad, and it is not linked, continue the
1448 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1449 GST_DEBUG_PAD_NAME (pad));
1450 GST_OBJECT_UNLOCK (pad);
1453 /* found a pad, stop search */
1454 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1455 GST_DEBUG_PAD_NAME (pad));
1456 GST_OBJECT_UNLOCK (pad);
1462 gst_object_ref (result);
1464 GST_OBJECT_UNLOCK (element);
1468 /* ERROR handling */
1471 g_warning ("unknown pad direction %d", dir);
1477 gst_element_default_send_event (GstElement * element, GstEvent * event)
1479 gboolean result = FALSE;
1482 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1483 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1484 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1487 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1488 "pushing %s event to random %s pad %s:%s",
1489 GST_EVENT_TYPE_NAME (event),
1490 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1491 GST_DEBUG_PAD_NAME (pad));
1493 result = gst_pad_push_event (pad, event);
1494 gst_object_unref (pad);
1496 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1497 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1498 gst_event_unref (event);
1504 * gst_element_send_event:
1505 * @element: a #GstElement to send the event to.
1506 * @event: (transfer full): the #GstEvent to send to the element.
1508 * Sends an event to an element. If the element doesn't implement an
1509 * event handler, the event will be pushed on a random linked sink pad for
1510 * upstream events or a random linked source pad for downstream events.
1512 * This function takes owership of the provided event so you should
1513 * gst_event_ref() it if you want to reuse the event after this call.
1515 * Returns: %TRUE if the event was handled.
1520 gst_element_send_event (GstElement * element, GstEvent * event)
1522 GstElementClass *oclass;
1523 gboolean result = FALSE;
1525 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1526 g_return_val_if_fail (event != NULL, FALSE);
1528 oclass = GST_ELEMENT_GET_CLASS (element);
1530 GST_STATE_LOCK (element);
1531 if (oclass->send_event) {
1532 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1533 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1534 result = oclass->send_event (element, event);
1536 GST_STATE_UNLOCK (element);
1543 * @element: a #GstElement to send the event to.
1544 * @rate: The new playback rate
1545 * @format: The format of the seek values
1546 * @flags: The optional seek flags.
1547 * @cur_type: The type and flags for the new current position
1548 * @cur: The value of the new current position
1549 * @stop_type: The type and flags for the new stop position
1550 * @stop: The value of the new stop position
1552 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1553 * the parameters. The seek event is sent to the element using
1554 * gst_element_send_event().
1556 * Returns: %TRUE if the event was handled.
1561 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1562 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1563 GstSeekType stop_type, gint64 stop)
1568 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1571 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1572 result = gst_element_send_event (element, event);
1578 gst_element_default_query (GstElement * element, GstQuery * query)
1580 gboolean result = FALSE;
1583 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1585 result = gst_pad_query (pad, query);
1587 gst_object_unref (pad);
1589 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1591 GstPad *peer = gst_pad_get_peer (pad);
1594 result = gst_pad_query (peer, query);
1596 gst_object_unref (peer);
1598 gst_object_unref (pad);
1605 * gst_element_query:
1606 * @element: a #GstElement to perform the query on.
1607 * @query: (transfer none): the #GstQuery.
1609 * Performs a query on the given element.
1611 * For elements that don't implement a query handler, this function
1612 * forwards the query to a random srcpad or to the peer of a
1613 * random linked sinkpad of this element.
1615 * Please note that some queries might need a running pipeline to work.
1617 * Returns: TRUE if the query could be performed.
1622 gst_element_query (GstElement * element, GstQuery * query)
1624 GstElementClass *oclass;
1625 gboolean result = FALSE;
1627 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1628 g_return_val_if_fail (query != NULL, FALSE);
1630 oclass = GST_ELEMENT_GET_CLASS (element);
1632 if (oclass->query) {
1633 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1634 GST_ELEMENT_NAME (element));
1635 result = oclass->query (element, query);
1641 * gst_element_post_message:
1642 * @element: a #GstElement posting the message
1643 * @message: (transfer full): a #GstMessage to post
1645 * Post a message on the element's #GstBus. This function takes ownership of the
1646 * message; if you want to access the message after this call, you should add an
1647 * additional reference before calling.
1649 * Returns: %TRUE if the message was successfully posted. The function returns
1650 * %FALSE if the element did not have a bus.
1655 gst_element_post_message (GstElement * element, GstMessage * message)
1658 gboolean result = FALSE;
1660 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1661 g_return_val_if_fail (message != NULL, FALSE);
1663 GST_OBJECT_LOCK (element);
1666 if (G_UNLIKELY (bus == NULL))
1669 gst_object_ref (bus);
1670 GST_OBJECT_UNLOCK (element);
1672 /* we release the element lock when posting the message so that any
1673 * (synchronous) message handlers can operate on the element */
1674 result = gst_bus_post (bus, message);
1675 gst_object_unref (bus);
1682 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1683 "not posting message %p: no bus", message);
1684 GST_OBJECT_UNLOCK (element);
1685 gst_message_unref (message);
1691 * _gst_element_error_printf:
1692 * @format: the printf-like format to use, or %NULL
1694 * This function is only used internally by the gst_element_error() macro.
1696 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1702 _gst_element_error_printf (const gchar * format, ...)
1712 va_start (args, format);
1713 buffer = g_strdup_vprintf (format, args);
1719 * gst_element_message_full:
1720 * @element: a #GstElement to send message from
1721 * @type: the #GstMessageType
1722 * @domain: the GStreamer GError domain this message belongs to
1723 * @code: the GError code belonging to the domain
1724 * @text: (allow-none) (transfer full): an allocated text string to be used
1725 * as a replacement for the default message connected to code,
1727 * @debug: (allow-none) (transfer full): an allocated debug message to be
1728 * used as a replacement for the default debugging information,
1730 * @file: the source code file where the error was generated
1731 * @function: the source code function where the error was generated
1732 * @line: the source code line where the error was generated
1734 * Post an error, warning or info message on the bus from inside an element.
1736 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1737 * #GST_MESSAGE_INFO.
1741 void gst_element_message_full
1742 (GstElement * element, GstMessageType type,
1743 GQuark domain, gint code, gchar * text,
1744 gchar * debug, const gchar * file, const gchar * function, gint line)
1746 GError *gerror = NULL;
1750 gboolean has_debug = TRUE;
1751 GstMessage *message = NULL;
1754 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1755 g_return_if_fail (GST_IS_ELEMENT (element));
1756 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1757 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1759 /* check if we send the given text or the default error text */
1760 if ((text == NULL) || (text[0] == 0)) {
1761 /* text could have come from g_strdup_printf (""); */
1763 sent_text = gst_error_get_message (domain, code);
1767 /* construct a sent_debug with extra information from source */
1768 if ((debug == NULL) || (debug[0] == 0)) {
1769 /* debug could have come from g_strdup_printf (""); */
1773 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1775 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1776 file, line, function, name, debug);
1778 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1779 file, line, function, name);
1783 /* create gerror and post message */
1784 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1786 gerror = g_error_new_literal (domain, code, sent_text);
1789 case GST_MESSAGE_ERROR:
1791 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1793 case GST_MESSAGE_WARNING:
1794 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1797 case GST_MESSAGE_INFO:
1798 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1802 g_assert_not_reached ();
1805 gst_element_post_message (element, message);
1807 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1808 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1811 g_error_free (gerror);
1812 g_free (sent_debug);
1817 * gst_element_is_locked_state:
1818 * @element: a #GstElement.
1820 * Checks if the state of an element is locked.
1821 * If the state of an element is locked, state changes of the parent don't
1822 * affect the element.
1823 * This way you can leave currently unused elements inside bins. Just lock their
1824 * state before changing the state from #GST_STATE_NULL.
1828 * Returns: TRUE, if the element's state is locked.
1831 gst_element_is_locked_state (GstElement * element)
1835 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1837 GST_OBJECT_LOCK (element);
1838 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1839 GST_OBJECT_UNLOCK (element);
1845 * gst_element_set_locked_state:
1846 * @element: a #GstElement
1847 * @locked_state: TRUE to lock the element's state
1849 * Locks the state of an element, so state changes of the parent don't affect
1850 * this element anymore.
1854 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1855 * or the elements state-locking needed no change.
1858 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1862 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1864 GST_OBJECT_LOCK (element);
1865 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1867 if (G_UNLIKELY (old == locked_state))
1871 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1872 GST_ELEMENT_NAME (element));
1873 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1875 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1876 GST_ELEMENT_NAME (element));
1877 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1879 GST_OBJECT_UNLOCK (element);
1885 GST_CAT_DEBUG (GST_CAT_STATES,
1886 "elements %s was already in locked state %d",
1887 GST_ELEMENT_NAME (element), old);
1888 GST_OBJECT_UNLOCK (element);
1895 * gst_element_sync_state_with_parent:
1896 * @element: a #GstElement.
1898 * Tries to change the state of the element to the same as its parent.
1899 * If this function returns FALSE, the state of element is undefined.
1901 * Returns: TRUE, if the element's state could be synced to the parent's state.
1906 gst_element_sync_state_with_parent (GstElement * element)
1910 GstStateChangeReturn ret;
1912 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1914 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1915 GstState parent_current, parent_pending;
1917 GST_OBJECT_LOCK (parent);
1918 parent_current = GST_STATE (parent);
1919 parent_pending = GST_STATE_PENDING (parent);
1920 GST_OBJECT_UNLOCK (parent);
1922 /* set to pending if there is one, else we set it to the current state of
1924 if (parent_pending != GST_STATE_VOID_PENDING)
1925 target = parent_pending;
1927 target = parent_current;
1929 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1930 "syncing state (%s) to parent %s %s (%s, %s)",
1931 gst_element_state_get_name (GST_STATE (element)),
1932 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1933 gst_element_state_get_name (parent_current),
1934 gst_element_state_get_name (parent_pending));
1936 ret = gst_element_set_state (element, target);
1937 if (ret == GST_STATE_CHANGE_FAILURE)
1940 gst_object_unref (parent);
1944 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1951 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1952 "syncing state failed (%s)",
1953 gst_element_state_change_return_get_name (ret));
1954 gst_object_unref (parent);
1960 static GstStateChangeReturn
1961 gst_element_get_state_func (GstElement * element,
1962 GstState * state, GstState * pending, GstClockTime timeout)
1964 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1965 GstState old_pending;
1967 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1968 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1970 GST_OBJECT_LOCK (element);
1971 ret = GST_STATE_RETURN (element);
1972 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1973 gst_element_state_change_return_get_name (ret));
1975 /* we got an error, report immediately */
1976 if (ret == GST_STATE_CHANGE_FAILURE)
1979 /* we got no_preroll, report immediately */
1980 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1983 /* no need to wait async if we are not async */
1984 if (ret != GST_STATE_CHANGE_ASYNC)
1987 old_pending = GST_STATE_PENDING (element);
1988 if (old_pending != GST_STATE_VOID_PENDING) {
1989 GTimeVal *timeval, abstimeout;
1992 if (timeout != GST_CLOCK_TIME_NONE) {
1993 glong add = timeout / 1000;
1998 /* make timeout absolute */
1999 g_get_current_time (&abstimeout);
2000 g_time_val_add (&abstimeout, add);
2001 timeval = &abstimeout;
2005 /* get cookie to detect state changes during waiting */
2006 cookie = element->state_cookie;
2008 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2009 "waiting for element to commit state");
2011 /* we have a pending state change, wait for it to complete */
2012 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2013 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2014 /* timeout triggered */
2015 ret = GST_STATE_CHANGE_ASYNC;
2017 if (cookie != element->state_cookie)
2020 /* could be success or failure */
2021 if (old_pending == GST_STATE (element)) {
2022 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2023 ret = GST_STATE_CHANGE_SUCCESS;
2025 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2026 ret = GST_STATE_CHANGE_FAILURE;
2029 /* if nothing is pending anymore we can return SUCCESS */
2030 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2031 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2032 ret = GST_STATE_CHANGE_SUCCESS;
2038 *state = GST_STATE (element);
2040 *pending = GST_STATE_PENDING (element);
2042 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2043 "state current: %s, pending: %s, result: %s",
2044 gst_element_state_get_name (GST_STATE (element)),
2045 gst_element_state_get_name (GST_STATE_PENDING (element)),
2046 gst_element_state_change_return_get_name (ret));
2047 GST_OBJECT_UNLOCK (element);
2054 *state = GST_STATE_VOID_PENDING;
2056 *pending = GST_STATE_VOID_PENDING;
2058 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2060 GST_OBJECT_UNLOCK (element);
2062 return GST_STATE_CHANGE_FAILURE;
2067 * gst_element_get_state:
2068 * @element: a #GstElement to get the state of.
2069 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2071 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2072 * state. Can be %NULL.
2073 * @timeout: a #GstClockTime to specify the timeout for an async
2074 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2076 * Gets the state of the element.
2078 * For elements that performed an ASYNC state change, as reported by
2079 * gst_element_set_state(), this function will block up to the
2080 * specified timeout value for the state change to complete.
2081 * If the element completes the state change or goes into
2082 * an error, this function returns immediately with a return value of
2083 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2085 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2086 * returns the current and pending state immediately.
2088 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2089 * successfully changed its state but is not able to provide data yet.
2090 * This mostly happens for live sources that only produce data in
2091 * %GST_STATE_PLAYING. While the state change return is equivalent to
2092 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2093 * some sink elements might not be able to complete their state change because
2094 * an element is not producing data to complete the preroll. When setting the
2095 * element to playing, the preroll will complete and playback will start.
2097 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2098 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2099 * element is still performing a state change or
2100 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2104 GstStateChangeReturn
2105 gst_element_get_state (GstElement * element,
2106 GstState * state, GstState * pending, GstClockTime timeout)
2108 GstElementClass *oclass;
2109 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2111 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2113 oclass = GST_ELEMENT_GET_CLASS (element);
2115 if (oclass->get_state)
2116 result = (oclass->get_state) (element, state, pending, timeout);
2122 * gst_element_abort_state:
2123 * @element: a #GstElement to abort the state of.
2125 * Abort the state change of the element. This function is used
2126 * by elements that do asynchronous state changes and find out
2127 * something is wrong.
2129 * This function should be called with the STATE_LOCK held.
2134 gst_element_abort_state (GstElement * element)
2138 #ifndef GST_DISABLE_GST_DEBUG
2142 g_return_if_fail (GST_IS_ELEMENT (element));
2144 GST_OBJECT_LOCK (element);
2145 pending = GST_STATE_PENDING (element);
2147 if (pending == GST_STATE_VOID_PENDING ||
2148 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2149 goto nothing_aborted;
2151 #ifndef GST_DISABLE_GST_DEBUG
2152 old_state = GST_STATE (element);
2154 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2155 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2156 gst_element_state_get_name (pending));
2160 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2162 GST_STATE_BROADCAST (element);
2163 GST_OBJECT_UNLOCK (element);
2169 GST_OBJECT_UNLOCK (element);
2174 /* Not static because GstBin has manual state handling too */
2176 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2177 GstState newstate, GstState pending)
2179 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2180 GstMessage *message;
2182 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2183 "notifying about state-changed %s to %s (%s pending)",
2184 gst_element_state_get_name (oldstate),
2185 gst_element_state_get_name (newstate),
2186 gst_element_state_get_name (pending));
2188 if (klass->state_changed)
2189 klass->state_changed (element, oldstate, newstate, pending);
2191 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2192 oldstate, newstate, pending);
2193 gst_element_post_message (element, message);
2197 * gst_element_continue_state:
2198 * @element: a #GstElement to continue the state change of.
2199 * @ret: The previous state return value
2201 * Commit the state change of the element and proceed to the next
2202 * pending state if any. This function is used
2203 * by elements that do asynchronous state changes.
2204 * The core will normally call this method automatically when an
2205 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2207 * If after calling this method the element still has not reached
2208 * the pending state, the next state change is performed.
2210 * This method is used internally and should normally not be called by plugins
2213 * Returns: The result of the commit state change.
2217 GstStateChangeReturn
2218 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2220 GstStateChangeReturn old_ret;
2221 GstState old_state, old_next;
2222 GstState current, next, pending;
2223 GstStateChange transition;
2225 GST_OBJECT_LOCK (element);
2226 old_ret = GST_STATE_RETURN (element);
2227 GST_STATE_RETURN (element) = ret;
2228 pending = GST_STATE_PENDING (element);
2230 /* check if there is something to commit */
2231 if (pending == GST_STATE_VOID_PENDING)
2232 goto nothing_pending;
2234 old_state = GST_STATE (element);
2235 /* this is the state we should go to next */
2236 old_next = GST_STATE_NEXT (element);
2237 /* update current state */
2238 current = GST_STATE (element) = old_next;
2240 /* see if we reached the final state */
2241 if (pending == current)
2244 next = GST_STATE_GET_NEXT (current, pending);
2245 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2247 GST_STATE_NEXT (element) = next;
2249 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2250 GST_OBJECT_UNLOCK (element);
2252 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2253 "committing state from %s to %s, pending %s, next %s",
2254 gst_element_state_get_name (old_state),
2255 gst_element_state_get_name (old_next),
2256 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2258 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2260 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2261 "continue state change %s to %s, final %s",
2262 gst_element_state_get_name (current),
2263 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2265 ret = gst_element_change_state (element, transition);
2271 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2272 GST_OBJECT_UNLOCK (element);
2277 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2278 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2280 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2281 "completed state change to %s", gst_element_state_get_name (pending));
2282 GST_OBJECT_UNLOCK (element);
2284 /* don't post silly messages with the same state. This can happen
2285 * when an element state is changed to what it already was. For bins
2286 * this can be the result of a lost state, which we check with the
2287 * previous return value.
2288 * We do signal the cond though as a _get_state() might be blocking
2290 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2291 _priv_gst_element_state_changed (element, old_state, old_next,
2292 GST_STATE_VOID_PENDING);
2294 GST_STATE_BROADCAST (element);
2301 * gst_element_lost_state:
2302 * @element: a #GstElement the state is lost of
2304 * Brings the element to the lost state. The current state of the
2305 * element is copied to the pending state so that any call to
2306 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2308 * An ASYNC_START message is posted. If the element was PLAYING, it will
2309 * go to PAUSED. The element will be restored to its PLAYING state by
2310 * the parent pipeline when it prerolls again.
2312 * This is mostly used for elements that lost their preroll buffer
2313 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2314 * they will go to their pending state again when a new preroll buffer is
2315 * queued. This function can only be called when the element is currently
2316 * not in error or an async state change.
2318 * This function is used internally and should normally not be called from
2319 * plugins or applications.
2322 gst_element_lost_state (GstElement * element)
2324 GstState old_state, new_state;
2325 GstMessage *message;
2327 g_return_if_fail (GST_IS_ELEMENT (element));
2329 GST_OBJECT_LOCK (element);
2330 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2333 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2334 goto only_async_start;
2336 old_state = GST_STATE (element);
2338 /* when we were PLAYING, the new state is PAUSED. We will also not
2339 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2340 * when we preroll. */
2341 if (old_state > GST_STATE_PAUSED)
2342 new_state = GST_STATE_PAUSED;
2344 new_state = old_state;
2346 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2347 "lost state of %s to %s", gst_element_state_get_name (old_state),
2348 gst_element_state_get_name (new_state));
2350 GST_STATE (element) = new_state;
2351 GST_STATE_NEXT (element) = new_state;
2352 GST_STATE_PENDING (element) = new_state;
2353 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2354 GST_OBJECT_UNLOCK (element);
2356 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2358 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2359 gst_element_post_message (element, message);
2365 GST_OBJECT_UNLOCK (element);
2370 GST_OBJECT_UNLOCK (element);
2372 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2373 gst_element_post_message (element, message);
2379 * gst_element_set_state:
2380 * @element: a #GstElement to change state of.
2381 * @state: the element's new #GstState.
2383 * Sets the state of the element. This function will try to set the
2384 * requested state by going through all the intermediary states and calling
2385 * the class's state change function for each.
2387 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2388 * element will perform the remainder of the state change asynchronously in
2390 * An application can use gst_element_get_state() to wait for the completion
2391 * of the state change or it can wait for a state change message on the bus.
2393 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2394 * #GST_STATE_CHANGE_ASYNC.
2396 * Returns: Result of the state change using #GstStateChangeReturn.
2400 GstStateChangeReturn
2401 gst_element_set_state (GstElement * element, GstState state)
2403 GstElementClass *oclass;
2404 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2406 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2408 oclass = GST_ELEMENT_GET_CLASS (element);
2410 if (oclass->set_state)
2411 result = (oclass->set_state) (element, state);
2417 * default set state function, calculates the next state based
2418 * on current state and calls the change_state function
2420 static GstStateChangeReturn
2421 gst_element_set_state_func (GstElement * element, GstState state)
2423 GstState current, next, old_pending;
2424 GstStateChangeReturn ret;
2425 GstStateChange transition;
2426 GstStateChangeReturn old_ret;
2428 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2430 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2431 gst_element_state_get_name (state));
2433 /* state lock is taken to protect the set_state() and get_state()
2434 * procedures, it does not lock any variables. */
2435 GST_STATE_LOCK (element);
2437 /* now calculate how to get to the new state */
2438 GST_OBJECT_LOCK (element);
2439 old_ret = GST_STATE_RETURN (element);
2440 /* previous state change returned an error, remove all pending
2441 * and next states */
2442 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2443 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2444 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2445 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2448 current = GST_STATE (element);
2449 next = GST_STATE_NEXT (element);
2450 old_pending = GST_STATE_PENDING (element);
2452 /* this is the (new) state we should go to. TARGET is the last state we set on
2454 if (state != GST_STATE_TARGET (element)) {
2455 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2456 "setting target state to %s", gst_element_state_get_name (state));
2457 GST_STATE_TARGET (element) = state;
2458 /* increment state cookie so that we can track each state change. We only do
2459 * this if this is actually a new state change. */
2460 element->state_cookie++;
2462 GST_STATE_PENDING (element) = state;
2464 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2465 "current %s, old_pending %s, next %s, old return %s",
2466 gst_element_state_get_name (current),
2467 gst_element_state_get_name (old_pending),
2468 gst_element_state_get_name (next),
2469 gst_element_state_change_return_get_name (old_ret));
2471 /* if the element was busy doing a state change, we just update the
2472 * target state, it'll get to it async then. */
2473 if (old_pending != GST_STATE_VOID_PENDING) {
2474 /* upwards state change will happen ASYNC */
2475 if (old_pending <= state)
2477 /* element is going to this state already */
2478 else if (next == state)
2480 /* element was performing an ASYNC upward state change and
2481 * we request to go downward again. Start from the next pending
2483 else if (next > state
2484 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2488 next = GST_STATE_GET_NEXT (current, state);
2489 /* now we store the next state */
2490 GST_STATE_NEXT (element) = next;
2491 /* mark busy, we need to check that there is actually a state change
2492 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2493 * the default element change_state function has no way to know what the
2494 * old value was... could consider this a FIXME...*/
2495 if (current != next)
2496 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2498 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2500 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2501 "%s: setting state from %s to %s",
2502 (next != state ? "intermediate" : "final"),
2503 gst_element_state_get_name (current), gst_element_state_get_name (next));
2505 /* now signal any waiters, they will error since the cookie was incremented */
2506 GST_STATE_BROADCAST (element);
2508 GST_OBJECT_UNLOCK (element);
2510 ret = gst_element_change_state (element, transition);
2512 GST_STATE_UNLOCK (element);
2514 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2515 gst_element_state_change_return_get_name (ret));
2521 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2522 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2523 "element was busy with async state change");
2524 GST_OBJECT_UNLOCK (element);
2526 GST_STATE_UNLOCK (element);
2528 return GST_STATE_CHANGE_ASYNC;
2533 * gst_element_change_state:
2534 * @element: a #GstElement
2535 * @transition: the requested transition
2537 * Perform @transition on @element.
2539 * This function must be called with STATE_LOCK held and is mainly used
2542 * Returns: the #GstStateChangeReturn of the state transition.
2544 GstStateChangeReturn
2545 gst_element_change_state (GstElement * element, GstStateChange transition)
2547 GstElementClass *oclass;
2548 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2550 oclass = GST_ELEMENT_GET_CLASS (element);
2552 /* call the state change function so it can set the state */
2553 if (oclass->change_state)
2554 ret = (oclass->change_state) (element, transition);
2556 ret = GST_STATE_CHANGE_FAILURE;
2559 case GST_STATE_CHANGE_FAILURE:
2560 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2561 "have FAILURE change_state return");
2562 /* state change failure */
2563 gst_element_abort_state (element);
2565 case GST_STATE_CHANGE_ASYNC:
2569 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2570 "element will change state ASYNC");
2572 target = GST_STATE_TARGET (element);
2574 if (target > GST_STATE_READY)
2577 /* else we just continue the state change downwards */
2578 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2579 "forcing commit state %s <= %s",
2580 gst_element_state_get_name (target),
2581 gst_element_state_get_name (GST_STATE_READY));
2583 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2586 case GST_STATE_CHANGE_SUCCESS:
2587 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2588 "element changed state SUCCESS");
2589 /* we can commit the state now which will proceeed to
2591 ret = gst_element_continue_state (element, ret);
2593 case GST_STATE_CHANGE_NO_PREROLL:
2594 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2595 "element changed state NO_PREROLL");
2596 /* we can commit the state now which will proceeed to
2598 ret = gst_element_continue_state (element, ret);
2601 goto invalid_return;
2604 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2609 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2617 GST_OBJECT_LOCK (element);
2618 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2619 g_critical ("%s: unknown return value %d from a state change function",
2620 GST_ELEMENT_NAME (element), ret);
2622 /* we are in error now */
2623 ret = GST_STATE_CHANGE_FAILURE;
2624 GST_STATE_RETURN (element) = ret;
2625 GST_OBJECT_UNLOCK (element);
2631 /* gst_iterator_fold functions for pads_activate
2632 * Stop the iterator if activating one pad failed. */
2634 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2636 GstPad *pad = g_value_get_object (vpad);
2637 gboolean cont = TRUE;
2639 if (!(cont = gst_pad_set_active (pad, *active)))
2640 g_value_set_boolean (ret, FALSE);
2645 /* returns false on error or early cutout of the fold, true if all
2646 * pads in @iter were (de)activated successfully. */
2648 iterator_activate_fold_with_resync (GstIterator * iter,
2649 GstIteratorFoldFunction func, gpointer user_data)
2651 GstIteratorResult ires;
2654 /* no need to unset this later, it's just a boolean */
2655 g_value_init (&ret, G_TYPE_BOOLEAN);
2656 g_value_set_boolean (&ret, TRUE);
2659 ires = gst_iterator_fold (iter, func, &ret, user_data);
2661 case GST_ITERATOR_RESYNC:
2662 /* need to reset the result again */
2663 g_value_set_boolean (&ret, TRUE);
2664 gst_iterator_resync (iter);
2666 case GST_ITERATOR_DONE:
2667 /* all pads iterated, return collected value */
2670 /* iterator returned _ERROR or premature end with _OK,
2671 * mark an error and exit */
2672 g_value_set_boolean (&ret, FALSE);
2677 /* return collected value */
2678 return g_value_get_boolean (&ret);
2681 /* is called with STATE_LOCK
2683 * Pads are activated from source pads to sinkpads.
2686 gst_element_pads_activate (GstElement * element, gboolean active)
2691 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2692 "pads_activate with active %d", active);
2694 iter = gst_element_iterate_src_pads (element);
2696 iterator_activate_fold_with_resync (iter,
2697 (GstIteratorFoldFunction) activate_pads, &active);
2698 gst_iterator_free (iter);
2699 if (G_UNLIKELY (!res))
2702 iter = gst_element_iterate_sink_pads (element);
2704 iterator_activate_fold_with_resync (iter,
2705 (GstIteratorFoldFunction) activate_pads, &active);
2706 gst_iterator_free (iter);
2707 if (G_UNLIKELY (!res))
2710 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2711 "pads_activate successful");
2718 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2719 "source pads_activate failed");
2724 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2725 "sink pads_activate failed");
2730 /* is called with STATE_LOCK */
2731 static GstStateChangeReturn
2732 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2734 GstState state, next;
2735 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2737 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2739 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2740 next = GST_STATE_TRANSITION_NEXT (transition);
2742 /* if the element already is in the given state, we just return success */
2743 if (next == GST_STATE_VOID_PENDING || state == next)
2746 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2747 "default handler tries setting state from %s to %s (%04x)",
2748 gst_element_state_get_name (state),
2749 gst_element_state_get_name (next), transition);
2751 switch (transition) {
2752 case GST_STATE_CHANGE_NULL_TO_READY:
2754 case GST_STATE_CHANGE_READY_TO_PAUSED:
2755 if (!gst_element_pads_activate (element, TRUE)) {
2756 result = GST_STATE_CHANGE_FAILURE;
2759 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2761 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2763 case GST_STATE_CHANGE_PAUSED_TO_READY:
2764 case GST_STATE_CHANGE_READY_TO_NULL:
2765 /* deactivate pads in both cases, since they are activated on
2766 ready->paused but the element might not have made it to paused */
2767 if (!gst_element_pads_activate (element, FALSE)) {
2768 result = GST_STATE_CHANGE_FAILURE;
2772 /* this will catch real but unhandled state changes;
2773 * can only be caused by:
2774 * - a new state was added
2775 * - somehow the element was asked to jump across an intermediate state
2777 g_warning ("Unhandled state change from %s to %s",
2778 gst_element_state_get_name (state),
2779 gst_element_state_get_name (next));
2786 GST_OBJECT_LOCK (element);
2787 result = GST_STATE_RETURN (element);
2788 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2789 "element is already in the %s state",
2790 gst_element_state_get_name (state));
2791 GST_OBJECT_UNLOCK (element);
2798 * gst_element_get_factory:
2799 * @element: a #GstElement to request the element factory of.
2801 * Retrieves the factory that was used to create this element.
2803 * Returns: (transfer none): the #GstElementFactory used for creating this
2804 * element. no refcounting is needed.
2807 gst_element_get_factory (GstElement * element)
2809 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2811 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2815 gst_element_dispose (GObject * object)
2817 GstElement *element = GST_ELEMENT_CAST (object);
2821 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2823 if (GST_STATE (element) != GST_STATE_NULL)
2826 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2827 "removing %d pads", g_list_length (element->pads));
2828 /* first we break all our links with the outside */
2829 while (element->pads && element->pads->data) {
2830 /* don't call _remove_pad with NULL */
2831 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2833 if (G_UNLIKELY (element->pads != NULL)) {
2834 g_critical ("could not remove pads from element %s",
2835 GST_STR_NULL (GST_OBJECT_NAME (object)));
2838 GST_OBJECT_LOCK (element);
2839 clock_p = &element->clock;
2840 bus_p = &element->bus;
2841 gst_object_replace ((GstObject **) clock_p, NULL);
2842 gst_object_replace ((GstObject **) bus_p, NULL);
2843 GST_OBJECT_UNLOCK (element);
2845 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2847 G_OBJECT_CLASS (parent_class)->dispose (object);
2856 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2858 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2860 "You need to explicitly set elements to the NULL state before\n"
2861 "dropping the final reference, to allow them to clean up.\n"
2862 "This problem may also be caused by a refcounting bug in the\n"
2863 "application or some element.\n",
2864 GST_OBJECT_NAME (element),
2865 gst_element_state_get_name (GST_STATE (element)),
2866 is_locked ? " (locked)" : "");
2872 gst_element_finalize (GObject * object)
2874 GstElement *element = GST_ELEMENT_CAST (object);
2876 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2878 g_cond_free (element->state_cond);
2879 g_static_rec_mutex_free (&element->state_lock);
2881 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2883 G_OBJECT_CLASS (parent_class)->finalize (object);
2887 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2891 g_return_if_fail (GST_IS_ELEMENT (element));
2893 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2895 GST_OBJECT_LOCK (element);
2896 bus_p = &GST_ELEMENT_BUS (element);
2897 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2898 GST_OBJECT_UNLOCK (element);
2902 * gst_element_set_bus:
2903 * @element: a #GstElement to set the bus of.
2904 * @bus: (transfer none): the #GstBus to set.
2906 * Sets the bus of the element. Increases the refcount on the bus.
2907 * For internal use only, unless you're testing elements.
2912 gst_element_set_bus (GstElement * element, GstBus * bus)
2914 GstElementClass *oclass;
2916 g_return_if_fail (GST_IS_ELEMENT (element));
2918 oclass = GST_ELEMENT_GET_CLASS (element);
2920 if (oclass->set_bus)
2921 oclass->set_bus (element, bus);
2925 * gst_element_get_bus:
2926 * @element: a #GstElement to get the bus of.
2928 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2929 * bus for the application.
2931 * Returns: (transfer full): the element's #GstBus. unref after usage.
2936 gst_element_get_bus (GstElement * element)
2938 GstBus *result = NULL;
2940 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2942 GST_OBJECT_LOCK (element);
2943 if ((result = GST_ELEMENT_BUS (element)))
2944 gst_object_ref (result);
2945 GST_OBJECT_UNLOCK (element);
2947 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,