2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * All elements have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * A pad of an element can be retrieved by name with gst_element_get_pad().
45 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
47 * Elements can be linked through their pads.
48 * If the link is straightforward, use the gst_element_link()
49 * convenience function to link two elements, or gst_element_link_many()
50 * for more elements in a row.
51 * Use gst_element_link_filtered() to link two elements constrained by
52 * a specified set of #GstCaps.
53 * For finer control, use gst_element_link_pads() and
54 * gst_element_link_pads_filtered() to specify the pads to link on
55 * each element by name.
57 * Each element has a state (see #GstState). You can get and set the state
58 * of an element with gst_element_get_state() and gst_element_set_state().
59 * Setting a state triggers a #GstStateChange. To get a string representation
60 * of a #GstState, use gst_element_state_get_name().
62 * You can get and set a #GstClock on an element using gst_element_get_clock()
63 * and gst_element_set_clock().
64 * Some elements can provide a clock for the pipeline if
65 * gst_element_provides_clock() returns %TRUE. With the
66 * gst_element_provide_clock() method one can retrieve the clock provided by
68 * Not all elements require a clock to operate correctly. If
69 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
70 * element with gst_element_set_clock().
72 * Note that clock slection and distribution is normally handled by the
73 * toplevel #GstPipeline so the clock functions are only to be used in very
74 * specific situations.
76 * Last reviewed on 2009-05-29 (0.10.24)
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstelementdetails.h"
86 #include "gstenumtypes.h"
88 #include "gstmarshal.h"
94 #include "gst-i18n-lib.h"
96 /* Element signals and args */
112 #ifdef GST_DISABLE_DEPRECATED
113 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
114 #include <libxml/parser.h>
115 xmlNodePtr gst_object_save_thyself (const GstObject * object,
117 GstObject *gst_object_load_thyself (xmlNodePtr parent);
118 void gst_pad_load_and_link (xmlNodePtr self, GstObject * parent);
122 static void gst_element_class_init (GstElementClass * klass);
123 static void gst_element_init (GstElement * element);
124 static void gst_element_base_class_init (gpointer g_class);
125 static void gst_element_base_class_finalize (gpointer g_class);
127 static void gst_element_dispose (GObject * object);
128 static void gst_element_finalize (GObject * object);
130 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
131 GstStateChange transition);
132 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
133 GstState * state, GstState * pending, GstClockTime timeout);
134 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
136 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
138 static gboolean gst_element_default_send_event (GstElement * element,
140 static gboolean gst_element_default_query (GstElement * element,
143 static GstPadTemplate
144 * gst_element_class_get_request_pad_template (GstElementClass *
145 element_class, const gchar * name);
147 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
148 static xmlNodePtr gst_element_save_thyself (GstObject * object,
150 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
153 static GstObjectClass *parent_class = NULL;
154 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
156 /* this is used in gstelementfactory.c:gst_element_register() */
157 GQuark _gst_elementclass_factory = 0;
160 gst_element_get_type (void)
162 static volatile gsize gst_element_type = 0;
164 if (g_once_init_enter (&gst_element_type)) {
166 static const GTypeInfo element_info = {
167 sizeof (GstElementClass),
168 gst_element_base_class_init,
169 gst_element_base_class_finalize,
170 (GClassInitFunc) gst_element_class_init,
175 (GInstanceInitFunc) gst_element_init,
179 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
180 &element_info, G_TYPE_FLAG_ABSTRACT);
182 _gst_elementclass_factory =
183 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
184 g_once_init_leave (&gst_element_type, _type);
186 return gst_element_type;
190 gst_element_class_init (GstElementClass * klass)
192 GObjectClass *gobject_class;
193 GstObjectClass *gstobject_class;
195 gobject_class = (GObjectClass *) klass;
196 gstobject_class = (GstObjectClass *) klass;
198 parent_class = g_type_class_peek_parent (klass);
201 * GstElement::pad-added:
202 * @gstelement: the object which received the signal
203 * @new_pad: the pad that has been added
205 * a new #GstPad has been added to the element.
207 gst_element_signals[PAD_ADDED] =
208 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
209 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
210 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
212 * GstElement::pad-removed:
213 * @gstelement: the object which received the signal
214 * @old_pad: the pad that has been removed
216 * a #GstPad has been removed from the element
218 gst_element_signals[PAD_REMOVED] =
219 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
220 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
221 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
223 * GstElement::no-more-pads:
224 * @gstelement: the object which received the signal
226 * This signals that the element will not generate more dynamic pads.
228 gst_element_signals[NO_MORE_PADS] =
229 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
230 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
231 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
233 gobject_class->dispose = gst_element_dispose;
234 gobject_class->finalize = gst_element_finalize;
236 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
237 gstobject_class->save_thyself =
238 ((gpointer (*)(GstObject * object,
239 gpointer self)) * GST_DEBUG_FUNCPTR (gst_element_save_thyself));
240 gstobject_class->restore_thyself =
241 ((void (*)(GstObject * object,
242 gpointer self)) *GST_DEBUG_FUNCPTR (gst_element_restore_thyself));
245 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
246 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
247 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
248 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
249 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
250 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
251 klass->numpadtemplates = 0;
253 klass->elementfactory = NULL;
257 gst_element_base_class_init (gpointer g_class)
259 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
261 /* FIXME 0.11: Copy the element details and instead of clearing the
262 * pad template list copy the list and increase the refcount of
263 * the pad templates by one.
265 * This will make it possible to add pad templates and set element
266 * details in the class_init functions and is the real GObject way
268 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
270 memset (&element_class->details, 0, sizeof (GstElementDetails));
271 element_class->meta_data = NULL;
272 element_class->padtemplates = NULL;
274 /* set the factory, see gst_element_register() */
275 element_class->elementfactory =
276 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
277 _gst_elementclass_factory);
278 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
279 element_class->elementfactory);
283 gst_element_base_class_finalize (gpointer g_class)
285 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
287 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
288 g_list_free (klass->padtemplates);
289 __gst_element_details_clear (&klass->details);
290 if (klass->meta_data) {
291 gst_structure_free (klass->meta_data);
292 klass->meta_data = NULL;
297 gst_element_init (GstElement * element)
299 GST_STATE (element) = GST_STATE_NULL;
300 GST_STATE_TARGET (element) = GST_STATE_NULL;
301 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
302 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
303 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
305 /* FIXME 0.11: Store this directly in the instance struct */
306 element->state_lock = g_slice_new (GStaticRecMutex);
307 g_static_rec_mutex_init (element->state_lock);
308 element->state_cond = g_cond_new ();
312 * gst_element_release_request_pad:
313 * @element: a #GstElement to release the request pad of.
314 * @pad: the #GstPad to release.
316 * Makes the element free the previously requested pad as obtained
317 * with gst_element_get_request_pad().
319 * This does not unref the pad. If the pad was created by using
320 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
321 * followed by gst_object_unref() to free the @pad.
326 gst_element_release_request_pad (GstElement * element, GstPad * pad)
328 GstElementClass *oclass;
330 g_return_if_fail (GST_IS_ELEMENT (element));
331 g_return_if_fail (GST_IS_PAD (pad));
333 oclass = GST_ELEMENT_GET_CLASS (element);
335 /* if the element implements a custom release function we call that, else we
336 * simply remove the pad from the element */
337 if (oclass->release_pad)
338 (oclass->release_pad) (element, pad);
340 gst_element_remove_pad (element, pad);
344 * gst_element_requires_clock:
345 * @element: a #GstElement to query
347 * Query if the element requires a clock.
349 * Returns: %TRUE if the element requires a clock
354 gst_element_requires_clock (GstElement * element)
358 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
360 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
366 * gst_element_provides_clock:
367 * @element: a #GstElement to query
369 * Query if the element provides a clock. A #GstClock provided by an
370 * element can be used as the global #GstClock for the pipeline.
371 * An element that can provide a clock is only required to do so in the PAUSED
372 * state, this means when it is fully negotiated and has allocated the resources
373 * to operate the clock.
375 * Returns: %TRUE if the element provides a clock
380 gst_element_provides_clock (GstElement * element)
384 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
386 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
392 * gst_element_provide_clock:
393 * @element: a #GstElement to query
395 * Get the clock provided by the given element.
396 * <note>An element is only required to provide a clock in the PAUSED
397 * state. Some elements can provide a clock in other states.</note>
399 * Returns: the GstClock provided by the element or %NULL
400 * if no clock could be provided. Unref after usage.
405 gst_element_provide_clock (GstElement * element)
407 GstClock *result = NULL;
408 GstElementClass *oclass;
410 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
412 oclass = GST_ELEMENT_GET_CLASS (element);
414 if (oclass->provide_clock)
415 result = oclass->provide_clock (element);
421 * gst_element_set_clock:
422 * @element: a #GstElement to set the clock for.
423 * @clock: the #GstClock to set for the element.
425 * Sets the clock for the element. This function increases the
426 * refcount on the clock. Any previously set clock on the object
429 * Returns: %TRUE if the element accepted the clock. An element can refuse a
430 * clock when it, for example, is not able to slave its internal clock to the
431 * @clock or when it requires a specific clock to operate.
436 gst_element_set_clock (GstElement * element, GstClock * clock)
438 GstElementClass *oclass;
442 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
443 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
445 oclass = GST_ELEMENT_GET_CLASS (element);
447 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
449 if (oclass->set_clock)
450 res = oclass->set_clock (element, clock);
453 /* only update the clock pointer if the element accepted the clock */
454 GST_OBJECT_LOCK (element);
455 clock_p = &element->clock;
456 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
457 GST_OBJECT_UNLOCK (element);
463 * gst_element_get_clock:
464 * @element: a #GstElement to get the clock of.
466 * Gets the currently configured clock of the element. This is the clock as was
467 * last set with gst_element_set_clock().
469 * Returns: the #GstClock of the element. unref after usage.
474 gst_element_get_clock (GstElement * element)
478 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
480 GST_OBJECT_LOCK (element);
481 if ((result = element->clock))
482 gst_object_ref (result);
483 GST_OBJECT_UNLOCK (element);
489 * gst_element_set_base_time:
490 * @element: a #GstElement.
491 * @time: the base time to set.
493 * Set the base time of an element. See gst_element_get_base_time().
498 gst_element_set_base_time (GstElement * element, GstClockTime time)
502 g_return_if_fail (GST_IS_ELEMENT (element));
504 GST_OBJECT_LOCK (element);
505 old = element->base_time;
506 element->base_time = time;
507 GST_OBJECT_UNLOCK (element);
509 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
510 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
511 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
515 * gst_element_get_base_time:
516 * @element: a #GstElement.
518 * Returns the base time of the element. The base time is the
519 * absolute time of the clock when this element was last put to
520 * PLAYING. Subtracting the base time from the clock time gives
521 * the running time of the element.
523 * Returns: the base time of the element.
528 gst_element_get_base_time (GstElement * element)
532 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
534 GST_OBJECT_LOCK (element);
535 result = element->base_time;
536 GST_OBJECT_UNLOCK (element);
542 * gst_element_set_start_time:
543 * @element: a #GstElement.
544 * @time: the base time to set.
546 * Set the start time of an element. The start time of the element is the
547 * running time of the element when it last went to the PAUSED state. In READY
548 * or after a flushing seek, it is set to 0.
550 * Toplevel elements like #GstPipeline will manage the start_time and
551 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
552 * on such a toplevel element will disable the distribution of the base_time to
553 * the children and can be useful if the application manages the base_time
554 * itself, for example if you want to synchronize capture from multiple
555 * pipelines, and you can also ensure that the pipelines have the same clock.
562 gst_element_set_start_time (GstElement * element, GstClockTime time)
566 g_return_if_fail (GST_IS_ELEMENT (element));
568 GST_OBJECT_LOCK (element);
569 old = GST_ELEMENT_START_TIME (element);
570 GST_ELEMENT_START_TIME (element) = time;
571 GST_OBJECT_UNLOCK (element);
573 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
574 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
575 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
579 * gst_element_get_start_time:
580 * @element: a #GstElement.
582 * Returns the start time of the element. The start time is the
583 * running time of the clock when this element was last put to PAUSED.
585 * Usually the start_time is managed by a toplevel element such as
590 * Returns: the start time of the element.
595 gst_element_get_start_time (GstElement * element)
599 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
601 GST_OBJECT_LOCK (element);
602 result = GST_ELEMENT_START_TIME (element);
603 GST_OBJECT_UNLOCK (element);
609 * gst_element_is_indexable:
610 * @element: a #GstElement.
612 * Queries if the element can be indexed.
614 * Returns: TRUE if the element can be indexed.
619 gst_element_is_indexable (GstElement * element)
623 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
625 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
631 * gst_element_set_index:
632 * @element: a #GstElement.
633 * @index: a #GstIndex.
635 * Set @index on the element. The refcount of the index
636 * will be increased, any previously set index is unreffed.
641 gst_element_set_index (GstElement * element, GstIndex * index)
643 GstElementClass *oclass;
645 g_return_if_fail (GST_IS_ELEMENT (element));
646 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
648 oclass = GST_ELEMENT_GET_CLASS (element);
650 if (oclass->set_index)
651 oclass->set_index (element, index);
655 * gst_element_get_index:
656 * @element: a #GstElement.
658 * Gets the index from the element.
660 * Returns: a #GstIndex or %NULL when no index was set on the
661 * element. unref after usage.
666 gst_element_get_index (GstElement * element)
668 GstElementClass *oclass;
669 GstIndex *result = NULL;
671 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
673 oclass = GST_ELEMENT_GET_CLASS (element);
675 if (oclass->get_index)
676 result = oclass->get_index (element);
682 * gst_element_add_pad:
683 * @element: a #GstElement to add the pad to.
684 * @pad: the #GstPad to add to the element.
686 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
687 * see gst_object_set_parent() for refcounting information.
689 * Pads are not automatically activated so elements should perform the needed
690 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
691 * state. See gst_pad_set_active() for more information about activating pads.
693 * The pad and the element should be unlocked when calling this function.
695 * This function will emit the #GstElement::pad-added signal on the element.
697 * Returns: %TRUE if the pad could be added. This function can fail when
698 * a pad with the same name already existed or the pad already had another
704 gst_element_add_pad (GstElement * element, GstPad * pad)
709 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
710 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
712 /* locking pad to look at the name */
713 GST_OBJECT_LOCK (pad);
714 pad_name = g_strdup (GST_PAD_NAME (pad));
715 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
716 GST_STR_NULL (pad_name));
717 flushing = GST_PAD_IS_FLUSHING (pad);
718 GST_OBJECT_UNLOCK (pad);
720 /* then check to see if there's already a pad by that name here */
721 GST_OBJECT_LOCK (element);
722 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
725 /* try to set the pad's parent */
726 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
727 GST_OBJECT_CAST (element))))
730 /* check for flushing pads */
731 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
732 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
733 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
734 "use gst_pad_set_active(pad,TRUE) before adding it.",
735 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
737 GST_OBJECT_LOCK (pad);
738 GST_PAD_UNSET_FLUSHING (pad);
739 GST_OBJECT_UNLOCK (pad);
744 /* add it to the list */
745 switch (gst_pad_get_direction (pad)) {
747 element->srcpads = g_list_prepend (element->srcpads, pad);
748 element->numsrcpads++;
751 element->sinkpads = g_list_prepend (element->sinkpads, pad);
752 element->numsinkpads++;
757 element->pads = g_list_prepend (element->pads, pad);
759 element->pads_cookie++;
760 GST_OBJECT_UNLOCK (element);
762 /* emit the PAD_ADDED signal */
763 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
770 g_critical ("Padname %s is not unique in element %s, not adding",
771 pad_name, GST_ELEMENT_NAME (element));
772 GST_OBJECT_UNLOCK (element);
779 ("Pad %s already has parent when trying to add to element %s",
780 pad_name, GST_ELEMENT_NAME (element));
781 GST_OBJECT_UNLOCK (element);
787 GST_OBJECT_LOCK (pad);
789 ("Trying to add pad %s to element %s, but it has no direction",
790 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
791 GST_OBJECT_UNLOCK (pad);
792 GST_OBJECT_UNLOCK (element);
798 * gst_element_remove_pad:
799 * @element: a #GstElement to remove pad from.
800 * @pad: the #GstPad to remove from the element.
802 * Removes @pad from @element. @pad will be destroyed if it has not been
803 * referenced elsewhere using gst_object_unparent().
805 * This function is used by plugin developers and should not be used
806 * by applications. Pads that were dynamically requested from elements
807 * with gst_element_get_request_pad() should be released with the
808 * gst_element_release_request_pad() function instead.
810 * Pads are not automatically deactivated so elements should perform the needed
811 * steps to deactivate the pad in case this pad is removed in the PAUSED or
812 * PLAYING state. See gst_pad_set_active() for more information about
815 * The pad and the element should be unlocked when calling this function.
817 * This function will emit the #GstElement::pad-removed signal on the element.
819 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
820 * pad does not belong to the provided element.
825 gst_element_remove_pad (GstElement * element, GstPad * pad)
829 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
830 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
832 /* locking pad to look at the name and parent */
833 GST_OBJECT_LOCK (pad);
834 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
835 GST_STR_NULL (GST_PAD_NAME (pad)));
837 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
839 GST_OBJECT_UNLOCK (pad);
842 if ((peer = gst_pad_get_peer (pad))) {
843 /* window for MT unsafeness, someone else could unlink here
844 * and then we call unlink with wrong pads. The unlink
845 * function would catch this and safely return failed. */
846 if (GST_PAD_IS_SRC (pad))
847 gst_pad_unlink (pad, peer);
849 gst_pad_unlink (peer, pad);
851 gst_object_unref (peer);
854 GST_OBJECT_LOCK (element);
855 /* remove it from the list */
856 switch (gst_pad_get_direction (pad)) {
858 element->srcpads = g_list_remove (element->srcpads, pad);
859 element->numsrcpads--;
862 element->sinkpads = g_list_remove (element->sinkpads, pad);
863 element->numsinkpads--;
866 g_critical ("Removing pad without direction???");
869 element->pads = g_list_remove (element->pads, pad);
871 element->pads_cookie++;
872 GST_OBJECT_UNLOCK (element);
874 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
875 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
877 gst_object_unparent (GST_OBJECT_CAST (pad));
884 /* FIXME, locking order? */
885 GST_OBJECT_LOCK (element);
886 g_critical ("Padname %s:%s does not belong to element %s when removing",
887 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
888 GST_OBJECT_UNLOCK (element);
889 GST_OBJECT_UNLOCK (pad);
895 * gst_element_no_more_pads:
896 * @element: a #GstElement
898 * Use this function to signal that the element does not expect any more pads
899 * to show up in the current pipeline. This function should be called whenever
900 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
901 * pad templates use this in combination with autopluggers to figure out that
902 * the element is done initializing its pads.
904 * This function emits the #GstElement::no-more-pads signal.
909 gst_element_no_more_pads (GstElement * element)
911 g_return_if_fail (GST_IS_ELEMENT (element));
913 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
917 pad_compare_name (GstPad * pad1, const gchar * name)
921 GST_OBJECT_LOCK (pad1);
922 result = strcmp (GST_PAD_NAME (pad1), name);
923 GST_OBJECT_UNLOCK (pad1);
929 * gst_element_get_static_pad:
930 * @element: a #GstElement to find a static pad of.
931 * @name: the name of the static #GstPad to retrieve.
933 * Retrieves a pad from @element by name. This version only retrieves
934 * already-existing (i.e. 'static') pads.
936 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
942 gst_element_get_static_pad (GstElement * element, const gchar * name)
945 GstPad *result = NULL;
947 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
948 g_return_val_if_fail (name != NULL, NULL);
950 GST_OBJECT_LOCK (element);
952 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
954 result = GST_PAD_CAST (find->data);
955 gst_object_ref (result);
958 if (result == NULL) {
959 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
960 name, GST_ELEMENT_NAME (element));
962 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
963 GST_ELEMENT_NAME (element), name);
965 GST_OBJECT_UNLOCK (element);
971 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
974 GstPad *newpad = NULL;
975 GstElementClass *oclass;
977 oclass = GST_ELEMENT_GET_CLASS (element);
979 if (oclass->request_new_pad)
980 newpad = (oclass->request_new_pad) (element, templ, name);
983 gst_object_ref (newpad);
989 * gst_element_get_request_pad:
990 * @element: a #GstElement to find a request pad of.
991 * @name: the name of the request #GstPad to retrieve.
993 * Retrieves a pad from the element by name. This version only retrieves
994 * request pads. The pad should be released with
995 * gst_element_release_request_pad().
997 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
1000 gst_element_get_request_pad (GstElement * element, const gchar * name)
1002 GstPadTemplate *templ = NULL;
1004 const gchar *req_name = NULL;
1005 gboolean templ_found = FALSE;
1008 gchar *str, *endptr = NULL;
1009 GstElementClass *class;
1011 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1012 g_return_val_if_fail (name != NULL, NULL);
1014 class = GST_ELEMENT_GET_CLASS (element);
1016 /* if the name contains a %, we assume it's the complete template name. Get
1017 * the template and try to get a pad */
1018 if (strstr (name, "%")) {
1019 templ = gst_element_class_get_request_pad_template (class, name);
1024 /* there is no % in the name, try to find a matching template */
1025 list = class->padtemplates;
1026 while (!templ_found && list) {
1027 templ = (GstPadTemplate *) list->data;
1028 if (templ->presence == GST_PAD_REQUEST) {
1029 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1030 templ->name_template);
1031 /* see if we find an exact match */
1032 if (strcmp (name, templ->name_template) == 0) {
1037 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1038 and %d, occurring at the end of the name_template, are the only
1040 else if ((str = strchr (templ->name_template, '%'))
1041 && strncmp (templ->name_template, name,
1042 str - templ->name_template) == 0
1043 && strlen (name) > str - templ->name_template) {
1044 data = name + (str - templ->name_template);
1045 if (*(str + 1) == 'd') {
1049 tmp = strtol (data, &endptr, 10);
1050 if (endptr && *endptr == '\0') {
1070 pad = gst_element_request_pad (element, templ, req_name);
1076 * gst_element_get_pad:
1077 * @element: a #GstElement.
1078 * @name: the name of the pad to retrieve.
1080 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1081 * first, then gst_element_get_request_pad().
1083 * Deprecated: This function is deprecated as it's unclear if the reference
1084 * to the result pad should be released with gst_object_unref() in case of a static pad
1085 * or gst_element_release_request_pad() in case of a request pad.
1086 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1088 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1089 * depending on the type of the pad.
1091 #ifndef GST_REMOVE_DEPRECATED
1092 #ifdef GST_DISABLE_DEPRECATED
1093 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1096 gst_element_get_pad (GstElement * element, const gchar * name)
1100 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1101 g_return_val_if_fail (name != NULL, NULL);
1103 pad = gst_element_get_static_pad (element, name);
1105 pad = gst_element_get_request_pad (element, name);
1109 #endif /* GST_REMOVE_DEPRECATED */
1111 static GstIteratorItem
1112 iterate_pad (GstIterator * it, GstPad * pad)
1114 gst_object_ref (pad);
1115 return GST_ITERATOR_ITEM_PASS;
1118 static GstIterator *
1119 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1121 GstIterator *result;
1123 GST_OBJECT_LOCK (element);
1124 gst_object_ref (element);
1125 result = gst_iterator_new_list (GST_TYPE_PAD,
1126 GST_OBJECT_GET_LOCK (element),
1127 &element->pads_cookie,
1130 (GstIteratorItemFunction) iterate_pad,
1131 (GstIteratorDisposeFunction) gst_object_unref);
1132 GST_OBJECT_UNLOCK (element);
1138 * gst_element_iterate_pads:
1139 * @element: a #GstElement to iterate pads of.
1141 * Retrieves an iterattor of @element's pads. The iterator should
1142 * be freed after usage.
1144 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1149 gst_element_iterate_pads (GstElement * element)
1151 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1153 return gst_element_iterate_pad_list (element, &element->pads);
1157 * gst_element_iterate_src_pads:
1158 * @element: a #GstElement.
1160 * Retrieves an iterator of @element's source pads.
1162 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1167 gst_element_iterate_src_pads (GstElement * element)
1169 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1171 return gst_element_iterate_pad_list (element, &element->srcpads);
1175 * gst_element_iterate_sink_pads:
1176 * @element: a #GstElement.
1178 * Retrieves an iterator of @element's sink pads.
1180 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1185 gst_element_iterate_sink_pads (GstElement * element)
1187 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1189 return gst_element_iterate_pad_list (element, &element->sinkpads);
1193 * gst_element_class_add_pad_template:
1194 * @klass: the #GstElementClass to add the pad template to.
1195 * @templ: a #GstPadTemplate to add to the element class.
1197 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1198 * functions of classes.
1201 gst_element_class_add_pad_template (GstElementClass * klass,
1202 GstPadTemplate * templ)
1204 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1205 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1207 /* FIXME 0.11: allow replacing the pad templates by
1208 * calling this with the same name as an already existing pad
1209 * template. For this we _must_ _not_ ref the added pad template
1210 * a second time and _must_ document that this function takes
1211 * ownership of the pad template. Otherwise we will leak pad templates
1212 * or the caller unref's the pad template and it disappears */
1213 /* avoid registering pad templates with the same name */
1214 g_return_if_fail (gst_element_class_get_pad_template (klass,
1215 templ->name_template) == NULL);
1217 klass->padtemplates = g_list_append (klass->padtemplates,
1218 gst_object_ref (templ));
1219 klass->numpadtemplates++;
1223 gst_element_class_add_meta_data (GstElementClass * klass,
1224 const gchar * key, const gchar * value)
1226 if (!klass->meta_data) {
1227 /* FIXME: use a quark for "metadata" */
1228 klass->meta_data = gst_structure_empty_new ("metadata");
1231 gst_structure_set ((GstStructure *) klass->meta_data,
1232 key, G_TYPE_STRING, value, NULL);
1236 * gst_element_class_set_documentation_uri:
1237 * @klass: class to set details for
1238 * @uri: uri of element documentation
1240 * Set uri pointing to user documentation. Applications can use this to show
1241 * help for e.g. effects to users.
1246 gst_element_class_set_documentation_uri (GstElementClass * klass,
1249 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1251 gst_element_class_add_meta_data (klass, "doc-uri", uri);
1255 * gst_element_class_set_icon_name:
1256 * @klass: class to set details for
1257 * @name: name of an icon
1259 * Elements that bridge to certain other products can include an icon of that
1260 * used product. Application can show the icon in menus/selectors to help
1261 * identifying specific elements.
1266 gst_element_class_set_icon_name (GstElementClass * klass, const gchar * name)
1268 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1270 gst_element_class_add_meta_data (klass, "icon-name", name);
1273 /* FIXME-0.11: deprecate and remove gst_element_class_set_details*() */
1275 * gst_element_class_set_details:
1276 * @klass: class to set details for
1277 * @details: details to set
1279 * Sets the detailed information for a #GstElementClass.
1280 * <note>This function is for use in _base_init functions only.</note>
1282 * The @details are copied.
1284 * Deprecated: Use gst_element_class_set_details_simple() instead.
1286 #ifndef GST_REMOVE_DEPRECATED
1287 #ifdef GST_DISABLE_DEPRECATED
1289 gst_element_class_set_details (GstElementClass * klass,
1290 const GstElementDetails * details);
1293 gst_element_class_set_details (GstElementClass * klass,
1294 const GstElementDetails * details)
1296 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1297 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1299 __gst_element_details_copy (&klass->details, details);
1304 * gst_element_class_set_details_simple:
1305 * @klass: class to set details for
1306 * @longname: The long English name of the element. E.g. "File Sink"
1307 * @classification: String describing the type of element, as an unordered list
1308 * separated with slashes ('/'). See draft-klass.txt of the design docs
1309 * for more details and common types. E.g: "Sink/File"
1310 * @description: Sentence describing the purpose of the element.
1311 * E.g: "Write stream to a file"
1312 * @author: Name and contact details of the author(s). Use \n to separate
1313 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1315 * Sets the detailed information for a #GstElementClass. Simpler version of
1316 * gst_element_class_set_details() that generates less linker overhead.
1317 * <note>This function is for use in _base_init functions only.</note>
1319 * The detail parameter strings are copied into the #GstElementDetails for
1320 * the element class.
1325 gst_element_class_set_details_simple (GstElementClass * klass,
1326 const gchar * longname, const gchar * classification,
1327 const gchar * description, const gchar * author)
1329 const GstElementDetails details =
1330 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1331 (gchar *) description, (gchar *) author);
1333 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1335 __gst_element_details_copy (&klass->details, &details);
1339 * gst_element_class_get_pad_template_list:
1340 * @element_class: a #GstElementClass to get pad templates of.
1342 * Retrieves a list of the pad templates associated with @element_class. The
1343 * list must not be modified by the calling code.
1344 * <note>If you use this function in the #GInstanceInitFunc of an object class
1345 * that has subclasses, make sure to pass the g_class parameter of the
1346 * #GInstanceInitFunc here.</note>
1348 * Returns: the #GList of padtemplates.
1351 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1353 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1355 return element_class->padtemplates;
1359 * gst_element_class_get_pad_template:
1360 * @element_class: a #GstElementClass to get the pad template of.
1361 * @name: the name of the #GstPadTemplate to get.
1363 * Retrieves a padtemplate from @element_class with the given name.
1364 * <note>If you use this function in the #GInstanceInitFunc of an object class
1365 * that has subclasses, make sure to pass the g_class parameter of the
1366 * #GInstanceInitFunc here.</note>
1368 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1369 * No unreferencing is necessary.
1372 gst_element_class_get_pad_template (GstElementClass * element_class,
1377 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1378 g_return_val_if_fail (name != NULL, NULL);
1380 padlist = element_class->padtemplates;
1383 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1385 if (strcmp (padtempl->name_template, name) == 0)
1388 padlist = g_list_next (padlist);
1394 static GstPadTemplate *
1395 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1398 GstPadTemplate *tmpl;
1400 tmpl = gst_element_class_get_pad_template (element_class, name);
1401 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1407 /* get a random pad on element of the given direction.
1408 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1411 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1412 GstPadDirection dir)
1414 GstPad *result = NULL;
1417 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1421 GST_OBJECT_LOCK (element);
1422 pads = element->srcpads;
1425 GST_OBJECT_LOCK (element);
1426 pads = element->sinkpads;
1429 goto wrong_direction;
1431 for (; pads; pads = g_list_next (pads)) {
1432 GstPad *pad = GST_PAD_CAST (pads->data);
1434 GST_OBJECT_LOCK (pad);
1435 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1436 GST_DEBUG_PAD_NAME (pad));
1438 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1439 /* if we require a linked pad, and it is not linked, continue the
1441 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1442 GST_DEBUG_PAD_NAME (pad));
1443 GST_OBJECT_UNLOCK (pad);
1446 /* found a pad, stop search */
1447 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1448 GST_DEBUG_PAD_NAME (pad));
1449 GST_OBJECT_UNLOCK (pad);
1455 gst_object_ref (result);
1457 GST_OBJECT_UNLOCK (element);
1461 /* ERROR handling */
1464 g_warning ("unknown pad direction %d", dir);
1470 gst_element_default_send_event (GstElement * element, GstEvent * event)
1472 gboolean result = FALSE;
1475 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1476 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1477 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1480 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1481 "pushing %s event to random %s pad %s:%s",
1482 GST_EVENT_TYPE_NAME (event),
1483 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1484 GST_DEBUG_PAD_NAME (pad));
1486 result = gst_pad_push_event (pad, event);
1487 gst_object_unref (pad);
1489 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1490 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1496 * gst_element_send_event:
1497 * @element: a #GstElement to send the event to.
1498 * @event: the #GstEvent to send to the element.
1500 * Sends an event to an element. If the element doesn't implement an
1501 * event handler, the event will be pushed on a random linked sink pad for
1502 * upstream events or a random linked source pad for downstream events.
1504 * This function takes owership of the provided event so you should
1505 * gst_event_ref() it if you want to reuse the event after this call.
1507 * Returns: %TRUE if the event was handled.
1512 gst_element_send_event (GstElement * element, GstEvent * event)
1514 GstElementClass *oclass;
1515 gboolean result = FALSE;
1517 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1518 g_return_val_if_fail (event != NULL, FALSE);
1520 oclass = GST_ELEMENT_GET_CLASS (element);
1522 GST_STATE_LOCK (element);
1523 if (oclass->send_event) {
1524 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1525 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1526 result = oclass->send_event (element, event);
1528 result = gst_element_default_send_event (element, event);
1530 GST_STATE_UNLOCK (element);
1537 * @element: a #GstElement to send the event to.
1538 * @rate: The new playback rate
1539 * @format: The format of the seek values
1540 * @flags: The optional seek flags.
1541 * @cur_type: The type and flags for the new current position
1542 * @cur: The value of the new current position
1543 * @stop_type: The type and flags for the new stop position
1544 * @stop: The value of the new stop position
1546 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1547 * the parameters. The seek event is sent to the element using
1548 * gst_element_send_event().
1550 * Returns: %TRUE if the event was handled.
1555 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1556 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1557 GstSeekType stop_type, gint64 stop)
1562 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1565 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1566 result = gst_element_send_event (element, event);
1572 * gst_element_get_query_types:
1573 * @element: a #GstElement to query
1575 * Get an array of query types from the element.
1576 * If the element doesn't implement a query types function,
1577 * the query will be forwarded to the peer of a random linked sink pad.
1579 * Returns: An array of #GstQueryType elements that should not
1580 * be freed or modified.
1584 const GstQueryType *
1585 gst_element_get_query_types (GstElement * element)
1587 GstElementClass *oclass;
1588 const GstQueryType *result = NULL;
1590 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1592 oclass = GST_ELEMENT_GET_CLASS (element);
1594 if (oclass->get_query_types) {
1595 result = oclass->get_query_types (element);
1597 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1600 GstPad *peer = gst_pad_get_peer (pad);
1603 result = gst_pad_get_query_types (peer);
1605 gst_object_unref (peer);
1607 gst_object_unref (pad);
1614 gst_element_default_query (GstElement * element, GstQuery * query)
1616 gboolean result = FALSE;
1619 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1621 result = gst_pad_query (pad, query);
1623 gst_object_unref (pad);
1625 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1627 GstPad *peer = gst_pad_get_peer (pad);
1630 result = gst_pad_query (peer, query);
1632 gst_object_unref (peer);
1634 gst_object_unref (pad);
1641 * gst_element_query:
1642 * @element: a #GstElement to perform the query on.
1643 * @query: the #GstQuery.
1645 * Performs a query on the given element.
1647 * For elements that don't implement a query handler, this function
1648 * forwards the query to a random srcpad or to the peer of a
1649 * random linked sinkpad of this element.
1651 * Please note that some queries might need a running pipeline to work.
1653 * Returns: TRUE if the query could be performed.
1658 gst_element_query (GstElement * element, GstQuery * query)
1660 GstElementClass *oclass;
1661 gboolean result = FALSE;
1663 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1664 g_return_val_if_fail (query != NULL, FALSE);
1666 oclass = GST_ELEMENT_GET_CLASS (element);
1668 if (oclass->query) {
1669 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1670 GST_ELEMENT_NAME (element));
1671 result = oclass->query (element, query);
1673 result = gst_element_default_query (element, query);
1679 * gst_element_post_message:
1680 * @element: a #GstElement posting the message
1681 * @message: a #GstMessage to post
1683 * Post a message on the element's #GstBus. This function takes ownership of the
1684 * message; if you want to access the message after this call, you should add an
1685 * additional reference before calling.
1687 * Returns: %TRUE if the message was successfully posted. The function returns
1688 * %FALSE if the element did not have a bus.
1693 gst_element_post_message (GstElement * element, GstMessage * message)
1696 gboolean result = FALSE;
1698 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1699 g_return_val_if_fail (message != NULL, FALSE);
1701 GST_OBJECT_LOCK (element);
1704 if (G_UNLIKELY (bus == NULL))
1707 gst_object_ref (bus);
1708 GST_OBJECT_UNLOCK (element);
1710 /* we release the element lock when posting the message so that any
1711 * (synchronous) message handlers can operate on the element */
1712 result = gst_bus_post (bus, message);
1713 gst_object_unref (bus);
1720 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1721 "not posting message %p: no bus", message);
1722 GST_OBJECT_UNLOCK (element);
1723 gst_message_unref (message);
1729 * _gst_element_error_printf:
1730 * @format: the printf-like format to use, or %NULL
1732 * This function is only used internally by the gst_element_error() macro.
1734 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1739 _gst_element_error_printf (const gchar * format, ...)
1749 va_start (args, format);
1750 buffer = g_strdup_vprintf (format, args);
1756 * gst_element_message_full:
1757 * @element: a #GstElement to send message from
1758 * @type: the #GstMessageType
1759 * @domain: the GStreamer GError domain this message belongs to
1760 * @code: the GError code belonging to the domain
1761 * @text: an allocated text string to be used as a replacement for the
1762 * default message connected to code, or %NULL
1763 * @debug: an allocated debug message to be used as a replacement for the
1764 * default debugging information, or %NULL
1765 * @file: the source code file where the error was generated
1766 * @function: the source code function where the error was generated
1767 * @line: the source code line where the error was generated
1769 * Post an error, warning or info message on the bus from inside an element.
1771 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1772 * #GST_MESSAGE_INFO.
1776 void gst_element_message_full
1777 (GstElement * element, GstMessageType type,
1778 GQuark domain, gint code, gchar * text,
1779 gchar * debug, const gchar * file, const gchar * function, gint line)
1781 GError *gerror = NULL;
1785 gboolean has_debug = TRUE;
1786 GstMessage *message = NULL;
1789 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1790 g_return_if_fail (GST_IS_ELEMENT (element));
1791 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1792 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1794 /* check if we send the given text or the default error text */
1795 if ((text == NULL) || (text[0] == 0)) {
1796 /* text could have come from g_strdup_printf (""); */
1798 sent_text = gst_error_get_message (domain, code);
1802 /* construct a sent_debug with extra information from source */
1803 if ((debug == NULL) || (debug[0] == 0)) {
1804 /* debug could have come from g_strdup_printf (""); */
1808 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1810 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1811 file, line, function, name, debug);
1813 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1814 file, line, function, name);
1818 /* create gerror and post message */
1819 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1821 gerror = g_error_new_literal (domain, code, sent_text);
1824 case GST_MESSAGE_ERROR:
1826 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1828 case GST_MESSAGE_WARNING:
1829 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1832 case GST_MESSAGE_INFO:
1833 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1837 g_assert_not_reached ();
1840 gst_element_post_message (element, message);
1842 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1843 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1846 g_error_free (gerror);
1847 g_free (sent_debug);
1852 * gst_element_is_locked_state:
1853 * @element: a #GstElement.
1855 * Checks if the state of an element is locked.
1856 * If the state of an element is locked, state changes of the parent don't
1857 * affect the element.
1858 * This way you can leave currently unused elements inside bins. Just lock their
1859 * state before changing the state from #GST_STATE_NULL.
1863 * Returns: TRUE, if the element's state is locked.
1866 gst_element_is_locked_state (GstElement * element)
1870 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1872 GST_OBJECT_LOCK (element);
1873 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1874 GST_OBJECT_UNLOCK (element);
1880 * gst_element_set_locked_state:
1881 * @element: a #GstElement
1882 * @locked_state: TRUE to lock the element's state
1884 * Locks the state of an element, so state changes of the parent don't affect
1885 * this element anymore.
1889 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1890 * or the elements state-locking needed no change.
1893 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1897 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1899 GST_OBJECT_LOCK (element);
1900 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1902 if (G_UNLIKELY (old == locked_state))
1906 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1907 GST_ELEMENT_NAME (element));
1908 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1910 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1911 GST_ELEMENT_NAME (element));
1912 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1914 GST_OBJECT_UNLOCK (element);
1920 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1921 GST_ELEMENT_NAME (element), old);
1922 GST_OBJECT_UNLOCK (element);
1929 * gst_element_sync_state_with_parent:
1930 * @element: a #GstElement.
1932 * Tries to change the state of the element to the same as its parent.
1933 * If this function returns FALSE, the state of element is undefined.
1935 * Returns: TRUE, if the element's state could be synced to the parent's state.
1940 gst_element_sync_state_with_parent (GstElement * element)
1944 GstStateChangeReturn ret;
1946 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1948 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1949 GstState parent_current, parent_pending;
1951 GST_OBJECT_LOCK (parent);
1952 parent_current = GST_STATE (parent);
1953 parent_pending = GST_STATE_PENDING (parent);
1954 GST_OBJECT_UNLOCK (parent);
1956 /* set to pending if there is one, else we set it to the current state of
1958 if (parent_pending != GST_STATE_VOID_PENDING)
1959 target = parent_pending;
1961 target = parent_current;
1963 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1964 "syncing state (%s) to parent %s %s (%s, %s)",
1965 gst_element_state_get_name (GST_STATE (element)),
1966 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1967 gst_element_state_get_name (parent_current),
1968 gst_element_state_get_name (parent_pending));
1970 ret = gst_element_set_state (element, target);
1971 if (ret == GST_STATE_CHANGE_FAILURE)
1974 gst_object_unref (parent);
1978 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1985 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1986 "syncing state failed (%s)",
1987 gst_element_state_change_return_get_name (ret));
1988 gst_object_unref (parent);
1994 static GstStateChangeReturn
1995 gst_element_get_state_func (GstElement * element,
1996 GstState * state, GstState * pending, GstClockTime timeout)
1998 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1999 GstState old_pending;
2001 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2002 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2004 GST_OBJECT_LOCK (element);
2005 ret = GST_STATE_RETURN (element);
2006 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2007 gst_element_state_change_return_get_name (ret));
2009 /* we got an error, report immediately */
2010 if (ret == GST_STATE_CHANGE_FAILURE)
2013 /* we got no_preroll, report immediatly */
2014 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2017 /* no need to wait async if we are not async */
2018 if (ret != GST_STATE_CHANGE_ASYNC)
2021 old_pending = GST_STATE_PENDING (element);
2022 if (old_pending != GST_STATE_VOID_PENDING) {
2023 GTimeVal *timeval, abstimeout;
2026 if (timeout != GST_CLOCK_TIME_NONE) {
2027 glong add = timeout / 1000;
2032 /* make timeout absolute */
2033 g_get_current_time (&abstimeout);
2034 g_time_val_add (&abstimeout, add);
2035 timeval = &abstimeout;
2039 /* get cookie to detect state changes during waiting */
2040 cookie = element->state_cookie;
2042 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2043 "waiting for element to commit state");
2045 /* we have a pending state change, wait for it to complete */
2046 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
2047 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2048 /* timeout triggered */
2049 ret = GST_STATE_CHANGE_ASYNC;
2051 if (cookie != element->state_cookie)
2054 /* could be success or failure */
2055 if (old_pending == GST_STATE (element)) {
2056 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2057 ret = GST_STATE_CHANGE_SUCCESS;
2059 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2060 ret = GST_STATE_CHANGE_FAILURE;
2063 /* if nothing is pending anymore we can return SUCCESS */
2064 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2065 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2066 ret = GST_STATE_CHANGE_SUCCESS;
2072 *state = GST_STATE (element);
2074 *pending = GST_STATE_PENDING (element);
2076 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2077 "state current: %s, pending: %s, result: %s",
2078 gst_element_state_get_name (GST_STATE (element)),
2079 gst_element_state_get_name (GST_STATE_PENDING (element)),
2080 gst_element_state_change_return_get_name (ret));
2081 GST_OBJECT_UNLOCK (element);
2088 *state = GST_STATE_VOID_PENDING;
2090 *pending = GST_STATE_VOID_PENDING;
2092 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2094 GST_OBJECT_UNLOCK (element);
2096 return GST_STATE_CHANGE_FAILURE;
2101 * gst_element_get_state:
2102 * @element: a #GstElement to get the state of.
2103 * @state: (out): a pointer to #GstState to hold the state. Can be %NULL.
2104 * @pending: (out): a pointer to #GstState to hold the pending state.
2106 * @timeout: a #GstClockTime to specify the timeout for an async
2107 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2109 * Gets the state of the element.
2111 * For elements that performed an ASYNC state change, as reported by
2112 * gst_element_set_state(), this function will block up to the
2113 * specified timeout value for the state change to complete.
2114 * If the element completes the state change or goes into
2115 * an error, this function returns immediately with a return value of
2116 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2118 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2119 * returns the current and pending state immediately.
2121 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2122 * successfully changed its state but is not able to provide data yet.
2123 * This mostly happens for live sources that only produce data in
2124 * %GST_STATE_PLAYING. While the state change return is equivalent to
2125 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2126 * some sink elements might not be able to complete their state change because
2127 * an element is not producing data to complete the preroll. When setting the
2128 * element to playing, the preroll will complete and playback will start.
2130 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2131 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2132 * element is still performing a state change or
2133 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2137 GstStateChangeReturn
2138 gst_element_get_state (GstElement * element,
2139 GstState * state, GstState * pending, GstClockTime timeout)
2141 GstElementClass *oclass;
2142 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2144 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2146 oclass = GST_ELEMENT_GET_CLASS (element);
2148 if (oclass->get_state)
2149 result = (oclass->get_state) (element, state, pending, timeout);
2155 * gst_element_abort_state:
2156 * @element: a #GstElement to abort the state of.
2158 * Abort the state change of the element. This function is used
2159 * by elements that do asynchronous state changes and find out
2160 * something is wrong.
2162 * This function should be called with the STATE_LOCK held.
2167 gst_element_abort_state (GstElement * element)
2171 #ifndef GST_DISABLE_GST_DEBUG
2175 g_return_if_fail (GST_IS_ELEMENT (element));
2177 GST_OBJECT_LOCK (element);
2178 pending = GST_STATE_PENDING (element);
2180 if (pending == GST_STATE_VOID_PENDING ||
2181 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2182 goto nothing_aborted;
2184 #ifndef GST_DISABLE_GST_DEBUG
2185 old_state = GST_STATE (element);
2187 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2188 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2189 gst_element_state_get_name (pending));
2193 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2195 GST_STATE_BROADCAST (element);
2196 GST_OBJECT_UNLOCK (element);
2202 GST_OBJECT_UNLOCK (element);
2208 * gst_element_continue_state:
2209 * @element: a #GstElement to continue the state change of.
2210 * @ret: The previous state return value
2212 * Commit the state change of the element and proceed to the next
2213 * pending state if any. This function is used
2214 * by elements that do asynchronous state changes.
2215 * The core will normally call this method automatically when an
2216 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2218 * If after calling this method the element still has not reached
2219 * the pending state, the next state change is performed.
2221 * This method is used internally and should normally not be called by plugins
2224 * Returns: The result of the commit state change.
2228 GstStateChangeReturn
2229 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2231 GstStateChangeReturn old_ret;
2232 GstState old_state, old_next;
2233 GstState current, next, pending;
2234 GstMessage *message;
2235 GstStateChange transition;
2237 GST_OBJECT_LOCK (element);
2238 old_ret = GST_STATE_RETURN (element);
2239 GST_STATE_RETURN (element) = ret;
2240 pending = GST_STATE_PENDING (element);
2242 /* check if there is something to commit */
2243 if (pending == GST_STATE_VOID_PENDING)
2244 goto nothing_pending;
2246 old_state = GST_STATE (element);
2247 /* this is the state we should go to next */
2248 old_next = GST_STATE_NEXT (element);
2249 /* update current state */
2250 current = GST_STATE (element) = old_next;
2252 /* see if we reached the final state */
2253 if (pending == current)
2256 next = GST_STATE_GET_NEXT (current, pending);
2257 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2259 GST_STATE_NEXT (element) = next;
2261 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2262 GST_OBJECT_UNLOCK (element);
2264 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2265 "committing state from %s to %s, pending %s, next %s",
2266 gst_element_state_get_name (old_state),
2267 gst_element_state_get_name (old_next),
2268 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2270 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2271 old_state, old_next, pending);
2272 gst_element_post_message (element, message);
2274 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2275 "continue state change %s to %s, final %s",
2276 gst_element_state_get_name (current),
2277 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2279 ret = gst_element_change_state (element, transition);
2285 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2286 GST_OBJECT_UNLOCK (element);
2291 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2292 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2294 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2295 "completed state change to %s", gst_element_state_get_name (pending));
2296 GST_OBJECT_UNLOCK (element);
2298 /* don't post silly messages with the same state. This can happen
2299 * when an element state is changed to what it already was. For bins
2300 * this can be the result of a lost state, which we check with the
2301 * previous return value.
2302 * We do signal the cond though as a _get_state() might be blocking
2304 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2305 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2306 "posting state-changed %s to %s",
2307 gst_element_state_get_name (old_state),
2308 gst_element_state_get_name (old_next));
2310 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2311 old_next, GST_STATE_VOID_PENDING);
2312 gst_element_post_message (element, message);
2315 GST_STATE_BROADCAST (element);
2322 * gst_element_lost_state_full:
2323 * @element: a #GstElement the state is lost of
2324 * @new_base_time: if a new base time should be distributed
2326 * Brings the element to the lost state. The current state of the
2327 * element is copied to the pending state so that any call to
2328 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2330 * An ASYNC_START message is posted with indication to distribute a new
2331 * base_time to the element when @new_base_time is %TRUE.
2332 * If the element was PLAYING, it will go to PAUSED. The element
2333 * will be restored to its PLAYING state by the parent pipeline when it
2336 * This is mostly used for elements that lost their preroll buffer
2337 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2338 * they will go to their pending state again when a new preroll buffer is
2339 * queued. This function can only be called when the element is currently
2340 * not in error or an async state change.
2342 * This function is used internally and should normally not be called from
2343 * plugins or applications.
2350 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2352 GstState old_state, new_state;
2353 GstMessage *message;
2355 g_return_if_fail (GST_IS_ELEMENT (element));
2357 GST_OBJECT_LOCK (element);
2358 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2361 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2362 goto only_async_start;
2364 old_state = GST_STATE (element);
2366 /* when we were PLAYING, the new state is PAUSED. We will also not
2367 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2368 * when we preroll. */
2369 if (old_state > GST_STATE_PAUSED)
2370 new_state = GST_STATE_PAUSED;
2372 new_state = old_state;
2374 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2375 "lost state of %s to %s", gst_element_state_get_name (old_state),
2376 gst_element_state_get_name (new_state));
2378 GST_STATE (element) = new_state;
2379 GST_STATE_NEXT (element) = new_state;
2380 GST_STATE_PENDING (element) = new_state;
2381 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2383 GST_ELEMENT_START_TIME (element) = 0;
2384 GST_OBJECT_UNLOCK (element);
2386 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2387 new_state, new_state, new_state);
2388 gst_element_post_message (element, message);
2391 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2392 gst_element_post_message (element, message);
2398 GST_OBJECT_UNLOCK (element);
2403 GST_OBJECT_UNLOCK (element);
2405 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2406 gst_element_post_message (element, message);
2412 * gst_element_lost_state:
2413 * @element: a #GstElement the state is lost of
2415 * Brings the element to the lost state. This function calls
2416 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2418 * This function is used internally and should normally not be called from
2419 * plugins or applications.
2424 gst_element_lost_state (GstElement * element)
2426 gst_element_lost_state_full (element, TRUE);
2430 * gst_element_set_state:
2431 * @element: a #GstElement to change state of.
2432 * @state: the element's new #GstState.
2434 * Sets the state of the element. This function will try to set the
2435 * requested state by going through all the intermediary states and calling
2436 * the class's state change function for each.
2438 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2439 * element will perform the remainder of the state change asynchronously in
2441 * An application can use gst_element_get_state() to wait for the completion
2442 * of the state change or it can wait for a state change message on the bus.
2444 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2445 * #GST_STATE_CHANGE_ASYNC.
2447 * Returns: Result of the state change using #GstStateChangeReturn.
2451 GstStateChangeReturn
2452 gst_element_set_state (GstElement * element, GstState state)
2454 GstElementClass *oclass;
2455 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2457 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2459 oclass = GST_ELEMENT_GET_CLASS (element);
2461 if (oclass->set_state)
2462 result = (oclass->set_state) (element, state);
2468 * default set state function, calculates the next state based
2469 * on current state and calls the change_state function
2471 static GstStateChangeReturn
2472 gst_element_set_state_func (GstElement * element, GstState state)
2474 GstState current, next, old_pending;
2475 GstStateChangeReturn ret;
2476 GstStateChange transition;
2477 GstStateChangeReturn old_ret;
2479 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2481 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2482 gst_element_state_get_name (state));
2484 /* state lock is taken to protect the set_state() and get_state()
2485 * procedures, it does not lock any variables. */
2486 GST_STATE_LOCK (element);
2488 /* now calculate how to get to the new state */
2489 GST_OBJECT_LOCK (element);
2490 old_ret = GST_STATE_RETURN (element);
2491 /* previous state change returned an error, remove all pending
2492 * and next states */
2493 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2494 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2495 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2496 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2499 current = GST_STATE (element);
2500 next = GST_STATE_NEXT (element);
2501 old_pending = GST_STATE_PENDING (element);
2503 /* this is the (new) state we should go to. TARGET is the last state we set on
2505 if (state != GST_STATE_TARGET (element)) {
2506 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2507 "setting target state to %s", gst_element_state_get_name (state));
2508 GST_STATE_TARGET (element) = state;
2509 /* increment state cookie so that we can track each state change. We only do
2510 * this if this is actually a new state change. */
2511 element->state_cookie++;
2513 GST_STATE_PENDING (element) = state;
2515 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2516 "current %s, old_pending %s, next %s, old return %s",
2517 gst_element_state_get_name (current),
2518 gst_element_state_get_name (old_pending),
2519 gst_element_state_get_name (next),
2520 gst_element_state_change_return_get_name (old_ret));
2522 /* if the element was busy doing a state change, we just update the
2523 * target state, it'll get to it async then. */
2524 if (old_pending != GST_STATE_VOID_PENDING) {
2525 /* upwards state change will happen ASYNC */
2526 if (old_pending <= state)
2528 /* element is going to this state already */
2529 else if (next == state)
2531 /* element was performing an ASYNC upward state change and
2532 * we request to go downward again. Start from the next pending
2534 else if (next > state
2535 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2539 next = GST_STATE_GET_NEXT (current, state);
2540 /* now we store the next state */
2541 GST_STATE_NEXT (element) = next;
2542 /* mark busy, we need to check that there is actually a state change
2543 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2544 * the default element change_state function has no way to know what the
2545 * old value was... could consider this a FIXME...*/
2546 if (current != next)
2547 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2549 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2551 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2552 "%s: setting state from %s to %s",
2553 (next != state ? "intermediate" : "final"),
2554 gst_element_state_get_name (current), gst_element_state_get_name (next));
2556 /* now signal any waiters, they will error since the cookie was incremented */
2557 GST_STATE_BROADCAST (element);
2559 GST_OBJECT_UNLOCK (element);
2561 ret = gst_element_change_state (element, transition);
2563 GST_STATE_UNLOCK (element);
2565 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2566 gst_element_state_change_return_get_name (ret));
2572 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2573 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2574 "element was busy with async state change");
2575 GST_OBJECT_UNLOCK (element);
2577 GST_STATE_UNLOCK (element);
2579 return GST_STATE_CHANGE_ASYNC;
2584 * gst_element_change_state:
2585 * @element: a #GstElement
2586 * @transition: the requested transition
2588 * Perform @transition on @element.
2590 * This function must be called with STATE_LOCK held and is mainly used
2593 * Returns: the #GstStateChangeReturn of the state transition.
2595 GstStateChangeReturn
2596 gst_element_change_state (GstElement * element, GstStateChange transition)
2598 GstElementClass *oclass;
2599 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2601 oclass = GST_ELEMENT_GET_CLASS (element);
2603 /* call the state change function so it can set the state */
2604 if (oclass->change_state)
2605 ret = (oclass->change_state) (element, transition);
2607 ret = GST_STATE_CHANGE_FAILURE;
2610 case GST_STATE_CHANGE_FAILURE:
2611 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2612 "have FAILURE change_state return");
2613 /* state change failure */
2614 gst_element_abort_state (element);
2616 case GST_STATE_CHANGE_ASYNC:
2620 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2621 "element will change state ASYNC");
2623 target = GST_STATE_TARGET (element);
2625 if (target > GST_STATE_READY)
2628 /* else we just continue the state change downwards */
2629 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2630 "forcing commit state %s <= %s",
2631 gst_element_state_get_name (target),
2632 gst_element_state_get_name (GST_STATE_READY));
2634 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2637 case GST_STATE_CHANGE_SUCCESS:
2638 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2639 "element changed state SUCCESS");
2640 /* we can commit the state now which will proceeed to
2642 ret = gst_element_continue_state (element, ret);
2644 case GST_STATE_CHANGE_NO_PREROLL:
2645 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2646 "element changed state NO_PREROLL");
2647 /* we can commit the state now which will proceeed to
2649 ret = gst_element_continue_state (element, ret);
2652 goto invalid_return;
2655 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2660 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2668 GST_OBJECT_LOCK (element);
2669 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2670 g_critical ("%s: unknown return value %d from a state change function",
2671 GST_ELEMENT_NAME (element), ret);
2673 /* we are in error now */
2674 ret = GST_STATE_CHANGE_FAILURE;
2675 GST_STATE_RETURN (element) = ret;
2676 GST_OBJECT_UNLOCK (element);
2682 /* gst_iterator_fold functions for pads_activate
2683 * Note how we don't stop the iterator when we fail an activation. This is
2684 * probably a FIXME since when one pad activation fails, we don't want to
2685 * continue our state change. */
2687 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2689 if (!gst_pad_set_active (pad, *active))
2690 g_value_set_boolean (ret, FALSE);
2692 /* unref the object that was reffed for us by _fold */
2693 gst_object_unref (pad);
2697 /* set the caps on the pad to NULL */
2699 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2701 gst_pad_set_caps (pad, NULL);
2702 gst_object_unref (pad);
2706 /* returns false on error or early cutout (will never happen because the fold
2707 * function always returns TRUE, see FIXME above) of the fold, true if all
2708 * pads in @iter were (de)activated successfully. */
2710 iterator_activate_fold_with_resync (GstIterator * iter,
2711 GstIteratorFoldFunction func, gpointer user_data)
2713 GstIteratorResult ires;
2716 /* no need to unset this later, it's just a boolean */
2717 g_value_init (&ret, G_TYPE_BOOLEAN);
2718 g_value_set_boolean (&ret, TRUE);
2721 ires = gst_iterator_fold (iter, func, &ret, user_data);
2723 case GST_ITERATOR_RESYNC:
2724 /* need to reset the result again */
2725 g_value_set_boolean (&ret, TRUE);
2726 gst_iterator_resync (iter);
2728 case GST_ITERATOR_DONE:
2729 /* all pads iterated, return collected value */
2732 /* iterator returned _ERROR or premature end with _OK,
2733 * mark an error and exit */
2734 g_value_set_boolean (&ret, FALSE);
2739 /* return collected value */
2740 return g_value_get_boolean (&ret);
2743 /* is called with STATE_LOCK
2745 * Pads are activated from source pads to sinkpads.
2748 gst_element_pads_activate (GstElement * element, gboolean active)
2753 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2754 "pads_activate with active %d", active);
2756 iter = gst_element_iterate_src_pads (element);
2758 iterator_activate_fold_with_resync (iter,
2759 (GstIteratorFoldFunction) activate_pads, &active);
2760 gst_iterator_free (iter);
2761 if (G_UNLIKELY (!res))
2764 iter = gst_element_iterate_sink_pads (element);
2766 iterator_activate_fold_with_resync (iter,
2767 (GstIteratorFoldFunction) activate_pads, &active);
2768 gst_iterator_free (iter);
2769 if (G_UNLIKELY (!res))
2773 /* clear the caps on all pads, this should never fail */
2774 iter = gst_element_iterate_pads (element);
2776 iterator_activate_fold_with_resync (iter,
2777 (GstIteratorFoldFunction) clear_caps, &active);
2778 gst_iterator_free (iter);
2779 if (G_UNLIKELY (!res))
2783 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2784 "pads_activate successful");
2791 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2792 "source pads_activate failed");
2797 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2798 "sink pads_activate failed");
2803 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2804 "failed to clear caps on pads");
2809 /* is called with STATE_LOCK */
2810 static GstStateChangeReturn
2811 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2813 GstState state, next;
2814 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2817 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2819 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2820 next = GST_STATE_TRANSITION_NEXT (transition);
2822 /* if the element already is in the given state, we just return success */
2823 if (next == GST_STATE_VOID_PENDING || state == next)
2826 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2827 "default handler tries setting state from %s to %s (%04x)",
2828 gst_element_state_get_name (state),
2829 gst_element_state_get_name (next), transition);
2831 switch (transition) {
2832 case GST_STATE_CHANGE_NULL_TO_READY:
2834 case GST_STATE_CHANGE_READY_TO_PAUSED:
2835 if (!gst_element_pads_activate (element, TRUE)) {
2836 result = GST_STATE_CHANGE_FAILURE;
2839 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2841 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2843 case GST_STATE_CHANGE_PAUSED_TO_READY:
2844 case GST_STATE_CHANGE_READY_TO_NULL:
2845 /* deactivate pads in both cases, since they are activated on
2846 ready->paused but the element might not have made it to paused */
2847 if (!gst_element_pads_activate (element, FALSE)) {
2848 result = GST_STATE_CHANGE_FAILURE;
2850 gst_element_set_base_time (element, 0);
2853 /* In null state release the reference to the clock */
2854 GST_OBJECT_LOCK (element);
2855 clock_p = &element->clock;
2856 gst_object_replace ((GstObject **) clock_p, NULL);
2857 GST_OBJECT_UNLOCK (element);
2860 /* this will catch real but unhandled state changes;
2861 * can only be caused by:
2862 * - a new state was added
2863 * - somehow the element was asked to jump across an intermediate state
2865 g_warning ("Unhandled state change from %s to %s",
2866 gst_element_state_get_name (state),
2867 gst_element_state_get_name (next));
2874 GST_OBJECT_LOCK (element);
2875 result = GST_STATE_RETURN (element);
2876 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2877 "element is already in the %s state",
2878 gst_element_state_get_name (state));
2879 GST_OBJECT_UNLOCK (element);
2886 * gst_element_get_factory:
2887 * @element: a #GstElement to request the element factory of.
2889 * Retrieves the factory that was used to create this element.
2891 * Returns: the #GstElementFactory used for creating this element.
2892 * no refcounting is needed.
2895 gst_element_get_factory (GstElement * element)
2897 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2899 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2903 gst_element_dispose (GObject * object)
2905 GstElement *element = GST_ELEMENT_CAST (object);
2909 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2911 if (GST_STATE (element) != GST_STATE_NULL)
2914 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2915 "removing %d pads", g_list_length (element->pads));
2916 /* first we break all our links with the outside */
2917 while (element->pads && element->pads->data) {
2918 /* don't call _remove_pad with NULL */
2919 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2921 if (G_UNLIKELY (element->pads != NULL)) {
2922 g_critical ("could not remove pads from element %s",
2923 GST_STR_NULL (GST_OBJECT_NAME (object)));
2926 GST_OBJECT_LOCK (element);
2927 clock_p = &element->clock;
2928 bus_p = &element->bus;
2929 gst_object_replace ((GstObject **) clock_p, NULL);
2930 gst_object_replace ((GstObject **) bus_p, NULL);
2931 GST_OBJECT_UNLOCK (element);
2933 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2935 G_OBJECT_CLASS (parent_class)->dispose (object);
2944 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2946 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2948 "You need to explicitly set elements to the NULL state before\n"
2949 "dropping the final reference, to allow them to clean up.\n"
2950 "This problem may also be caused by a refcounting bug in the\n"
2951 "application or some element.\n",
2952 GST_OBJECT_NAME (element),
2953 gst_element_state_get_name (GST_STATE (element)),
2954 is_locked ? " (locked)" : "");
2960 gst_element_finalize (GObject * object)
2962 GstElement *element = GST_ELEMENT_CAST (object);
2964 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2966 GST_STATE_LOCK (element);
2967 if (element->state_cond)
2968 g_cond_free (element->state_cond);
2969 element->state_cond = NULL;
2970 GST_STATE_UNLOCK (element);
2971 g_static_rec_mutex_free (element->state_lock);
2972 g_slice_free (GStaticRecMutex, element->state_lock);
2973 element->state_lock = NULL;
2975 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2977 G_OBJECT_CLASS (parent_class)->finalize (object);
2980 #if !defined(GST_DISABLE_LOADSAVE) && !defined(GST_REMOVE_DEPRECATED)
2982 * gst_element_save_thyself:
2983 * @element: a #GstElement to save.
2984 * @parent: the xml parent node.
2986 * Saves the element as part of the given XML structure.
2988 * Returns: the new #xmlNodePtr.
2991 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2994 GstElementClass *oclass;
2995 GParamSpec **specs, *spec;
2998 GValue value = { 0, };
2999 GstElement *element;
3001 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
3003 element = GST_ELEMENT_CAST (object);
3005 oclass = GST_ELEMENT_GET_CLASS (element);
3007 xmlNewChild (parent, NULL, (xmlChar *) "name",
3008 (xmlChar *) GST_ELEMENT_NAME (element));
3010 if (oclass->elementfactory != NULL) {
3011 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
3013 xmlNewChild (parent, NULL, (xmlChar *) "type",
3014 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
3018 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
3020 for (i = 0; i < nspecs; i++) {
3022 if (spec->flags & G_PARAM_READABLE) {
3026 g_value_init (&value, spec->value_type);
3028 g_object_get_property (G_OBJECT (element), spec->name, &value);
3029 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
3030 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
3032 if (G_IS_PARAM_SPEC_STRING (spec))
3033 contents = g_value_dup_string (&value);
3034 else if (G_IS_PARAM_SPEC_ENUM (spec))
3035 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
3036 else if (G_IS_PARAM_SPEC_INT64 (spec))
3037 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
3038 g_value_get_int64 (&value));
3039 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
3040 if (g_value_get_boxed (&value) != NULL) {
3041 contents = g_strdup_value_contents (&value);
3043 contents = g_strdup ("NULL");
3046 contents = g_strdup_value_contents (&value);
3048 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
3051 g_value_unset (&value);
3057 pads = g_list_last (GST_ELEMENT_PADS (element));
3060 GstPad *pad = GST_PAD_CAST (pads->data);
3062 /* figure out if it's a direct pad or a ghostpad */
3063 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
3064 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
3066 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
3068 pads = g_list_previous (pads);
3075 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3077 xmlNodePtr children;
3078 GstElement *element;
3080 gchar *value = NULL;
3082 element = GST_ELEMENT_CAST (object);
3083 g_return_if_fail (element != NULL);
3086 children = self->xmlChildrenNode;
3088 if (!strcmp ((char *) children->name, "param")) {
3089 xmlNodePtr child = children->xmlChildrenNode;
3092 if (!strcmp ((char *) child->name, "name")) {
3093 name = (gchar *) xmlNodeGetContent (child);
3094 } else if (!strcmp ((char *) child->name, "value")) {
3095 value = (gchar *) xmlNodeGetContent (child);
3097 child = child->next;
3099 /* FIXME: can this just be g_object_set ? */
3100 gst_util_set_object_arg (G_OBJECT (element), name, value);
3101 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3105 children = children->next;
3109 children = self->xmlChildrenNode;
3111 if (!strcmp ((char *) children->name, "pad")) {
3112 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3114 children = children->next;
3117 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3118 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3120 #endif /* GST_DISABLE_LOADSAVE */
3123 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3127 g_return_if_fail (GST_IS_ELEMENT (element));
3129 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3131 GST_OBJECT_LOCK (element);
3132 bus_p = &GST_ELEMENT_BUS (element);
3133 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3134 GST_OBJECT_UNLOCK (element);
3138 * gst_element_set_bus:
3139 * @element: a #GstElement to set the bus of.
3140 * @bus: the #GstBus to set.
3142 * Sets the bus of the element. Increases the refcount on the bus.
3143 * For internal use only, unless you're testing elements.
3148 gst_element_set_bus (GstElement * element, GstBus * bus)
3150 GstElementClass *oclass;
3152 g_return_if_fail (GST_IS_ELEMENT (element));
3154 oclass = GST_ELEMENT_GET_CLASS (element);
3156 if (oclass->set_bus)
3157 oclass->set_bus (element, bus);
3161 * gst_element_get_bus:
3162 * @element: a #GstElement to get the bus of.
3164 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3165 * bus for the application.
3167 * Returns: the element's #GstBus. unref after usage.
3172 gst_element_get_bus (GstElement * element)
3174 GstBus *result = NULL;
3176 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3178 GST_OBJECT_LOCK (element);
3179 if ((result = GST_ELEMENT_BUS (element)))
3180 gst_object_ref (result);
3181 GST_OBJECT_UNLOCK (element);
3183 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,