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 static void gst_element_class_init (GstElementClass * klass);
113 static void gst_element_init (GstElement * element);
114 static void gst_element_base_class_init (gpointer g_class);
115 static void gst_element_base_class_finalize (gpointer g_class);
117 static void gst_element_dispose (GObject * object);
118 static void gst_element_finalize (GObject * object);
120 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
121 GstStateChange transition);
122 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
123 GstState * state, GstState * pending, GstClockTime timeout);
124 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
126 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
128 static gboolean gst_element_default_send_event (GstElement * element,
130 static gboolean gst_element_default_query (GstElement * element,
133 static GstPadTemplate
134 * gst_element_class_get_request_pad_template (GstElementClass *
135 element_class, const gchar * name);
137 #ifndef GST_DISABLE_LOADSAVE
138 static xmlNodePtr gst_element_save_thyself (GstObject * object,
140 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
143 static GstObjectClass *parent_class = NULL;
144 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
146 /* this is used in gstelementfactory.c:gst_element_register() */
147 GQuark _gst_elementclass_factory = 0;
150 gst_element_get_type (void)
152 static volatile gsize gst_element_type = 0;
154 if (g_once_init_enter (&gst_element_type)) {
156 static const GTypeInfo element_info = {
157 sizeof (GstElementClass),
158 gst_element_base_class_init,
159 gst_element_base_class_finalize,
160 (GClassInitFunc) gst_element_class_init,
165 (GInstanceInitFunc) gst_element_init,
169 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
170 &element_info, G_TYPE_FLAG_ABSTRACT);
172 _gst_elementclass_factory =
173 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
174 g_once_init_leave (&gst_element_type, _type);
176 return gst_element_type;
180 gst_element_class_init (GstElementClass * klass)
182 GObjectClass *gobject_class;
183 GstObjectClass *gstobject_class;
185 gobject_class = (GObjectClass *) klass;
186 gstobject_class = (GstObjectClass *) klass;
188 parent_class = g_type_class_peek_parent (klass);
191 * GstElement::pad-added:
192 * @gstelement: the object which received the signal
193 * @new_pad: the pad that has been added
195 * a new #GstPad has been added to the element.
197 gst_element_signals[PAD_ADDED] =
198 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
199 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
200 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
202 * GstElement::pad-removed:
203 * @gstelement: the object which received the signal
204 * @old_pad: the pad that has been removed
206 * a #GstPad has been removed from the element
208 gst_element_signals[PAD_REMOVED] =
209 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
210 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
211 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
213 * GstElement::no-more-pads:
214 * @gstelement: the object which received the signal
216 * This signals that the element will not generate more dynamic pads.
218 gst_element_signals[NO_MORE_PADS] =
219 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
220 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
221 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
223 gobject_class->dispose = gst_element_dispose;
224 gobject_class->finalize = gst_element_finalize;
226 #ifndef GST_DISABLE_LOADSAVE
227 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
228 gstobject_class->restore_thyself =
229 GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
232 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
233 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
234 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
235 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
236 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
237 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
238 klass->numpadtemplates = 0;
240 klass->elementfactory = NULL;
244 gst_element_base_class_init (gpointer g_class)
246 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
248 /* FIXME 0.11: Copy the element details and instead of clearing the
249 * pad template list copy the list and increase the refcount of
250 * the pad templates by one.
252 * This will make it possible to add pad templates and set element
253 * details in the class_init functions and is the real GObject way
255 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
257 memset (&element_class->details, 0, sizeof (GstElementDetails));
258 element_class->padtemplates = NULL;
260 /* set the factory, see gst_element_register() */
261 element_class->elementfactory =
262 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
263 _gst_elementclass_factory);
264 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
265 element_class->elementfactory);
269 gst_element_base_class_finalize (gpointer g_class)
271 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
273 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
274 g_list_free (klass->padtemplates);
275 __gst_element_details_clear (&klass->details);
279 gst_element_init (GstElement * element)
281 GST_STATE (element) = GST_STATE_NULL;
282 GST_STATE_TARGET (element) = GST_STATE_NULL;
283 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
284 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
285 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
287 /* FIXME 0.11: Store this directly in the instance struct */
288 element->state_lock = g_slice_new (GStaticRecMutex);
289 g_static_rec_mutex_init (element->state_lock);
290 element->state_cond = g_cond_new ();
294 * gst_element_release_request_pad:
295 * @element: a #GstElement to release the request pad of.
296 * @pad: the #GstPad to release.
298 * Makes the element free the previously requested pad as obtained
299 * with gst_element_get_request_pad().
301 * This does not unref the pad. If the pad was created by using
302 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
303 * followed by gst_object_unref() to free the @pad.
308 gst_element_release_request_pad (GstElement * element, GstPad * pad)
310 GstElementClass *oclass;
312 g_return_if_fail (GST_IS_ELEMENT (element));
313 g_return_if_fail (GST_IS_PAD (pad));
315 oclass = GST_ELEMENT_GET_CLASS (element);
317 /* if the element implements a custom release function we call that, else we
318 * simply remove the pad from the element */
319 if (oclass->release_pad)
320 (oclass->release_pad) (element, pad);
322 gst_element_remove_pad (element, pad);
326 * gst_element_requires_clock:
327 * @element: a #GstElement to query
329 * Query if the element requires a clock.
331 * Returns: %TRUE if the element requires a clock
336 gst_element_requires_clock (GstElement * element)
340 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
342 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
348 * gst_element_provides_clock:
349 * @element: a #GstElement to query
351 * Query if the element provides a clock. A #GstClock provided by an
352 * element can be used as the global #GstClock for the pipeline.
353 * An element that can provide a clock is only required to do so in the PAUSED
354 * state, this means when it is fully negotiated and has allocated the resources
355 * to operate the clock.
357 * Returns: %TRUE if the element provides a clock
362 gst_element_provides_clock (GstElement * element)
366 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
368 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
374 * gst_element_provide_clock:
375 * @element: a #GstElement to query
377 * Get the clock provided by the given element.
378 * <note>An element is only required to provide a clock in the PAUSED
379 * state. Some elements can provide a clock in other states.</note>
381 * Returns: the GstClock provided by the element or %NULL
382 * if no clock could be provided. Unref after usage.
387 gst_element_provide_clock (GstElement * element)
389 GstClock *result = NULL;
390 GstElementClass *oclass;
392 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
394 oclass = GST_ELEMENT_GET_CLASS (element);
396 if (oclass->provide_clock)
397 result = oclass->provide_clock (element);
403 * gst_element_set_clock:
404 * @element: a #GstElement to set the clock for.
405 * @clock: the #GstClock to set for the element.
407 * Sets the clock for the element. This function increases the
408 * refcount on the clock. Any previously set clock on the object
411 * Returns: %TRUE if the element accepted the clock. An element can refuse a
412 * clock when it, for example, is not able to slave its internal clock to the
413 * @clock or when it requires a specific clock to operate.
418 gst_element_set_clock (GstElement * element, GstClock * clock)
420 GstElementClass *oclass;
424 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
425 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
427 oclass = GST_ELEMENT_GET_CLASS (element);
429 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
431 if (oclass->set_clock)
432 res = oclass->set_clock (element, clock);
435 /* only update the clock pointer if the element accepted the clock */
436 GST_OBJECT_LOCK (element);
437 clock_p = &element->clock;
438 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
439 GST_OBJECT_UNLOCK (element);
445 * gst_element_get_clock:
446 * @element: a #GstElement to get the clock of.
448 * Gets the currently configured clock of the element. This is the clock as was
449 * last set with gst_element_set_clock().
451 * Returns: the #GstClock of the element. unref after usage.
456 gst_element_get_clock (GstElement * element)
460 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
462 GST_OBJECT_LOCK (element);
463 if ((result = element->clock))
464 gst_object_ref (result);
465 GST_OBJECT_UNLOCK (element);
471 * gst_element_set_base_time:
472 * @element: a #GstElement.
473 * @time: the base time to set.
475 * Set the base time of an element. See gst_element_get_base_time().
480 gst_element_set_base_time (GstElement * element, GstClockTime time)
484 g_return_if_fail (GST_IS_ELEMENT (element));
486 GST_OBJECT_LOCK (element);
487 old = element->base_time;
488 element->base_time = time;
489 GST_OBJECT_UNLOCK (element);
491 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
492 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
493 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
497 * gst_element_get_base_time:
498 * @element: a #GstElement.
500 * Returns the base time of the element. The base time is the
501 * absolute time of the clock when this element was last put to
502 * PLAYING. Subtracting the base time from the clock time gives
503 * the running time of the element.
505 * Returns: the base time of the element.
510 gst_element_get_base_time (GstElement * element)
514 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
516 GST_OBJECT_LOCK (element);
517 result = element->base_time;
518 GST_OBJECT_UNLOCK (element);
524 * gst_element_set_start_time:
525 * @element: a #GstElement.
526 * @time: the base time to set.
528 * Set the start time of an element. The start time of the element is the
529 * running time of the element when it last went to the PAUSED state. In READY
530 * or after a flushing seek, it is set to 0.
532 * Toplevel elements like #GstPipeline will manage the start_time and
533 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
534 * on such a toplevel element will disable the distribution of the base_time to
535 * the children and can be useful if the application manages the base_time
536 * itself, for example if you want to synchronize capture from multiple
537 * pipelines, and you can also ensure that the pipelines have the same clock.
544 gst_element_set_start_time (GstElement * element, GstClockTime time)
548 g_return_if_fail (GST_IS_ELEMENT (element));
550 GST_OBJECT_LOCK (element);
551 old = GST_ELEMENT_START_TIME (element);
552 GST_ELEMENT_START_TIME (element) = time;
553 GST_OBJECT_UNLOCK (element);
555 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
556 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
557 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
561 * gst_element_get_start_time:
562 * @element: a #GstElement.
564 * Returns the start time of the element. The start time is the
565 * running time of the clock when this element was last put to PAUSED.
567 * Usually the start_time is managed by a toplevel element such as
572 * Returns: the start time of the element.
577 gst_element_get_start_time (GstElement * element)
581 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
583 GST_OBJECT_LOCK (element);
584 result = GST_ELEMENT_START_TIME (element);
585 GST_OBJECT_UNLOCK (element);
591 * gst_element_is_indexable:
592 * @element: a #GstElement.
594 * Queries if the element can be indexed.
596 * Returns: TRUE if the element can be indexed.
601 gst_element_is_indexable (GstElement * element)
605 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
607 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
613 * gst_element_set_index:
614 * @element: a #GstElement.
615 * @index: a #GstIndex.
617 * Set @index on the element. The refcount of the index
618 * will be increased, any previously set index is unreffed.
623 gst_element_set_index (GstElement * element, GstIndex * index)
625 GstElementClass *oclass;
627 g_return_if_fail (GST_IS_ELEMENT (element));
628 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
630 oclass = GST_ELEMENT_GET_CLASS (element);
632 if (oclass->set_index)
633 oclass->set_index (element, index);
637 * gst_element_get_index:
638 * @element: a #GstElement.
640 * Gets the index from the element.
642 * Returns: a #GstIndex or %NULL when no index was set on the
643 * element. unref after usage.
648 gst_element_get_index (GstElement * element)
650 GstElementClass *oclass;
651 GstIndex *result = NULL;
653 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
655 oclass = GST_ELEMENT_GET_CLASS (element);
657 if (oclass->get_index)
658 result = oclass->get_index (element);
664 * gst_element_add_pad:
665 * @element: a #GstElement to add the pad to.
666 * @pad: the #GstPad to add to the element.
668 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
669 * see gst_object_set_parent() for refcounting information.
671 * Pads are not automatically activated so elements should perform the needed
672 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
673 * state. See gst_pad_set_active() for more information about activating pads.
675 * The pad and the element should be unlocked when calling this function.
677 * This function will emit the #GstElement::pad-added signal on the element.
679 * Returns: %TRUE if the pad could be added. This function can fail when
680 * a pad with the same name already existed or the pad already had another
686 gst_element_add_pad (GstElement * element, GstPad * pad)
689 gboolean flushing, negotiable;
691 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
692 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
694 /* locking pad to look at the name */
695 GST_OBJECT_LOCK (pad);
696 pad_name = g_strdup (GST_PAD_NAME (pad));
697 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
698 GST_STR_NULL (pad_name));
699 flushing = GST_PAD_IS_FLUSHING (pad);
700 negotiable = GST_PAD_IS_NEGOTIABLE (pad);
701 GST_OBJECT_UNLOCK (pad);
703 /* then check to see if there's already a pad by that name here */
704 GST_OBJECT_LOCK (element);
705 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
708 /* try to set the pad's parent */
709 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
710 GST_OBJECT_CAST (element))))
713 /* sync pad state with element */
714 if (!negotiable && (GST_STATE (element) > GST_STATE_NULL ||
715 GST_STATE_NEXT (element) == GST_STATE_READY)) {
716 GST_OBJECT_LOCK (pad);
717 GST_PAD_SET_NEGOTIABLE (pad);
718 GST_OBJECT_UNLOCK (pad);
721 /* check for flushing pads */
722 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
723 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
724 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
725 "use gst_pad_set_active(pad,TRUE) before adding it.",
726 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
728 GST_OBJECT_LOCK (pad);
729 GST_PAD_UNSET_FLUSHING (pad);
730 GST_OBJECT_UNLOCK (pad);
735 /* add it to the list */
736 switch (gst_pad_get_direction (pad)) {
738 element->srcpads = g_list_prepend (element->srcpads, pad);
739 element->numsrcpads++;
742 element->sinkpads = g_list_prepend (element->sinkpads, pad);
743 element->numsinkpads++;
748 element->pads = g_list_prepend (element->pads, pad);
750 element->pads_cookie++;
751 GST_OBJECT_UNLOCK (element);
753 /* emit the PAD_ADDED signal */
754 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
761 g_critical ("Padname %s is not unique in element %s, not adding",
762 pad_name, GST_ELEMENT_NAME (element));
763 GST_OBJECT_UNLOCK (element);
770 ("Pad %s already has parent when trying to add to element %s",
771 pad_name, GST_ELEMENT_NAME (element));
772 GST_OBJECT_UNLOCK (element);
778 GST_OBJECT_LOCK (pad);
780 ("Trying to add pad %s to element %s, but it has no direction",
781 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
782 GST_OBJECT_UNLOCK (pad);
783 GST_OBJECT_UNLOCK (element);
789 * gst_element_remove_pad:
790 * @element: a #GstElement to remove pad from.
791 * @pad: the #GstPad to remove from the element.
793 * Removes @pad from @element. @pad will be destroyed if it has not been
794 * referenced elsewhere using gst_object_unparent().
796 * This function is used by plugin developers and should not be used
797 * by applications. Pads that were dynamically requested from elements
798 * with gst_element_get_request_pad() should be released with the
799 * gst_element_release_request_pad() function instead.
801 * Pads are not automatically deactivated so elements should perform the needed
802 * steps to deactivate the pad in case this pad is removed in the PAUSED or
803 * PLAYING state. See gst_pad_set_active() for more information about
806 * The pad and the element should be unlocked when calling this function.
808 * This function will emit the #GstElement::pad-removed signal on the element.
810 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
811 * pad does not belong to the provided element.
816 gst_element_remove_pad (GstElement * element, GstPad * pad)
820 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
821 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
823 /* locking pad to look at the name and parent */
824 GST_OBJECT_LOCK (pad);
825 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
826 GST_STR_NULL (GST_PAD_NAME (pad)));
828 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
830 GST_OBJECT_UNLOCK (pad);
833 if ((peer = gst_pad_get_peer (pad))) {
834 /* window for MT unsafeness, someone else could unlink here
835 * and then we call unlink with wrong pads. The unlink
836 * function would catch this and safely return failed. */
837 if (GST_PAD_IS_SRC (pad))
838 gst_pad_unlink (pad, peer);
840 gst_pad_unlink (peer, pad);
842 gst_object_unref (peer);
845 GST_OBJECT_LOCK (element);
846 /* remove it from the list */
847 switch (gst_pad_get_direction (pad)) {
849 element->srcpads = g_list_remove (element->srcpads, pad);
850 element->numsrcpads--;
853 element->sinkpads = g_list_remove (element->sinkpads, pad);
854 element->numsinkpads--;
857 g_critical ("Removing pad without direction???");
860 element->pads = g_list_remove (element->pads, pad);
862 element->pads_cookie++;
863 GST_OBJECT_UNLOCK (element);
865 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
866 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
868 gst_object_unparent (GST_OBJECT_CAST (pad));
875 /* FIXME, locking order? */
876 GST_OBJECT_LOCK (element);
877 g_critical ("Padname %s:%s does not belong to element %s when removing",
878 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
879 GST_OBJECT_UNLOCK (element);
880 GST_OBJECT_UNLOCK (pad);
886 * gst_element_no_more_pads:
887 * @element: a #GstElement
889 * Use this function to signal that the element does not expect any more pads
890 * to show up in the current pipeline. This function should be called whenever
891 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
892 * pad templates use this in combination with autopluggers to figure out that
893 * the element is done initializing its pads.
895 * This function emits the #GstElement::no-more-pads signal.
900 gst_element_no_more_pads (GstElement * element)
902 g_return_if_fail (GST_IS_ELEMENT (element));
904 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
908 pad_compare_name (GstPad * pad1, const gchar * name)
912 GST_OBJECT_LOCK (pad1);
913 result = strcmp (GST_PAD_NAME (pad1), name);
914 GST_OBJECT_UNLOCK (pad1);
920 * gst_element_get_static_pad:
921 * @element: a #GstElement to find a static pad of.
922 * @name: the name of the static #GstPad to retrieve.
924 * Retrieves a pad from @element by name. This version only retrieves
925 * already-existing (i.e. 'static') pads.
927 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
933 gst_element_get_static_pad (GstElement * element, const gchar * name)
936 GstPad *result = NULL;
938 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
939 g_return_val_if_fail (name != NULL, NULL);
941 GST_OBJECT_LOCK (element);
943 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
945 result = GST_PAD_CAST (find->data);
946 gst_object_ref (result);
949 if (result == NULL) {
950 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
951 name, GST_ELEMENT_NAME (element));
953 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
954 GST_ELEMENT_NAME (element), name);
956 GST_OBJECT_UNLOCK (element);
962 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
965 GstPad *newpad = NULL;
966 GstElementClass *oclass;
968 oclass = GST_ELEMENT_GET_CLASS (element);
970 if (oclass->request_new_pad)
971 newpad = (oclass->request_new_pad) (element, templ, name);
974 gst_object_ref (newpad);
980 * gst_element_get_request_pad:
981 * @element: a #GstElement to find a request pad of.
982 * @name: the name of the request #GstPad to retrieve.
984 * Retrieves a pad from the element by name. This version only retrieves
985 * request pads. The pad should be released with
986 * gst_element_release_request_pad().
988 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
991 gst_element_get_request_pad (GstElement * element, const gchar * name)
993 GstPadTemplate *templ = NULL;
995 const gchar *req_name = NULL;
996 gboolean templ_found = FALSE;
999 gchar *str, *endptr = NULL;
1000 GstElementClass *class;
1002 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1003 g_return_val_if_fail (name != NULL, NULL);
1005 class = GST_ELEMENT_GET_CLASS (element);
1007 /* if the name contains a %, we assume it's the complete template name. Get
1008 * the template and try to get a pad */
1009 if (strstr (name, "%")) {
1010 templ = gst_element_class_get_request_pad_template (class, name);
1015 /* there is no % in the name, try to find a matching template */
1016 list = class->padtemplates;
1017 while (!templ_found && list) {
1018 templ = (GstPadTemplate *) list->data;
1019 if (templ->presence == GST_PAD_REQUEST) {
1020 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1021 templ->name_template);
1022 /* see if we find an exact match */
1023 if (strcmp (name, templ->name_template) == 0) {
1028 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1029 and %d, occurring at the end of the name_template, are the only
1031 else if ((str = strchr (templ->name_template, '%'))
1032 && strncmp (templ->name_template, name,
1033 str - templ->name_template) == 0
1034 && strlen (name) > str - templ->name_template) {
1035 data = name + (str - templ->name_template);
1036 if (*(str + 1) == 'd') {
1040 tmp = strtol (data, &endptr, 10);
1041 if (endptr && *endptr == '\0') {
1061 pad = gst_element_request_pad (element, templ, req_name);
1067 * gst_element_get_pad:
1068 * @element: a #GstElement.
1069 * @name: the name of the pad to retrieve.
1071 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1072 * first, then gst_element_get_request_pad().
1074 * Deprecated: This function is deprecated as it's unclear if the reference
1075 * to the result pad should be released with gst_object_unref() in case of a static pad
1076 * or gst_element_release_request_pad() in case of a request pad.
1077 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1079 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1080 * depending on the type of the pad.
1082 #ifndef GST_REMOVE_DEPRECATED
1083 #ifdef GST_DISABLE_DEPRECATED
1084 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1087 gst_element_get_pad (GstElement * element, const gchar * name)
1091 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1092 g_return_val_if_fail (name != NULL, NULL);
1094 pad = gst_element_get_static_pad (element, name);
1096 pad = gst_element_get_request_pad (element, name);
1100 #endif /* GST_REMOVE_DEPRECATED */
1102 static GstIteratorItem
1103 iterate_pad (GstIterator * it, GstPad * pad)
1105 gst_object_ref (pad);
1106 return GST_ITERATOR_ITEM_PASS;
1109 static GstIterator *
1110 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1112 GstIterator *result;
1114 GST_OBJECT_LOCK (element);
1115 gst_object_ref (element);
1116 result = gst_iterator_new_list (GST_TYPE_PAD,
1117 GST_OBJECT_GET_LOCK (element),
1118 &element->pads_cookie,
1121 (GstIteratorItemFunction) iterate_pad,
1122 (GstIteratorDisposeFunction) gst_object_unref);
1123 GST_OBJECT_UNLOCK (element);
1129 * gst_element_iterate_pads:
1130 * @element: a #GstElement to iterate pads of.
1132 * Retrieves an iterattor of @element's pads. The iterator should
1133 * be freed after usage.
1135 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1140 gst_element_iterate_pads (GstElement * element)
1142 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1144 return gst_element_iterate_pad_list (element, &element->pads);
1148 * gst_element_iterate_src_pads:
1149 * @element: a #GstElement.
1151 * Retrieves an iterator of @element's source pads.
1153 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1158 gst_element_iterate_src_pads (GstElement * element)
1160 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1162 return gst_element_iterate_pad_list (element, &element->srcpads);
1166 * gst_element_iterate_sink_pads:
1167 * @element: a #GstElement.
1169 * Retrieves an iterator of @element's sink pads.
1171 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1176 gst_element_iterate_sink_pads (GstElement * element)
1178 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1180 return gst_element_iterate_pad_list (element, &element->sinkpads);
1184 * gst_element_class_add_pad_template:
1185 * @klass: the #GstElementClass to add the pad template to.
1186 * @templ: a #GstPadTemplate to add to the element class.
1188 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1189 * functions of classes.
1192 gst_element_class_add_pad_template (GstElementClass * klass,
1193 GstPadTemplate * templ)
1195 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1196 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1198 /* FIXME 0.11: allow replacing the pad templates by
1199 * calling this with the same name as an already existing pad
1200 * template. For this we _must_ _not_ ref the added pad template
1201 * a second time and _must_ document that this function takes
1202 * ownership of the pad template. Otherwise we will leak pad templates
1203 * or the caller unref's the pad template and it disappears */
1204 /* avoid registering pad templates with the same name */
1205 g_return_if_fail (gst_element_class_get_pad_template (klass,
1206 templ->name_template) == NULL);
1208 klass->padtemplates = g_list_append (klass->padtemplates,
1209 gst_object_ref (templ));
1210 klass->numpadtemplates++;
1214 * gst_element_class_set_details:
1215 * @klass: class to set details for
1216 * @details: details to set
1218 * Sets the detailed information for a #GstElementClass.
1219 * <note>This function is for use in _base_init functions only.</note>
1221 * The @details are copied.
1223 * Deprecated: Use gst_element_class_set_details_simple() instead.
1225 #ifndef GST_REMOVE_DEPRECATED
1226 #ifdef GST_DISABLE_DEPRECATED
1228 gst_element_class_set_details (GstElementClass * klass,
1229 const GstElementDetails * details);
1232 gst_element_class_set_details (GstElementClass * klass,
1233 const GstElementDetails * details)
1235 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1236 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1238 __gst_element_details_copy (&klass->details, details);
1243 * gst_element_class_set_details_simple:
1244 * @klass: class to set details for
1245 * @longname: The long English name of the element. E.g. "File Sink"
1246 * @classification: String describing the type of element, as an unordered list
1247 * separated with slashes ('/'). See draft-klass.txt of the design docs
1248 * for more details and common types. E.g: "Sink/File"
1249 * @description: Sentence describing the purpose of the element.
1250 * E.g: "Write stream to a file"
1251 * @author: Name and contact details of the author(s). Use \n to separate
1252 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1254 * Sets the detailed information for a #GstElementClass. Simpler version of
1255 * gst_element_class_set_details() that generates less linker overhead.
1256 * <note>This function is for use in _base_init functions only.</note>
1258 * The detail parameter strings are copied into the #GstElementDetails for
1259 * the element class.
1264 gst_element_class_set_details_simple (GstElementClass * klass,
1265 const gchar * longname, const gchar * classification,
1266 const gchar * description, const gchar * author)
1268 const GstElementDetails details =
1269 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1270 (gchar *) description, (gchar *) author);
1272 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1274 __gst_element_details_copy (&klass->details, &details);
1278 * gst_element_class_get_pad_template_list:
1279 * @element_class: a #GstElementClass to get pad templates of.
1281 * Retrieves a list of the pad templates associated with @element_class. The
1282 * list must not be modified by the calling code.
1283 * <note>If you use this function in the #GInstanceInitFunc of an object class
1284 * that has subclasses, make sure to pass the g_class parameter of the
1285 * #GInstanceInitFunc here.</note>
1287 * Returns: the #GList of padtemplates.
1290 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1292 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1294 return element_class->padtemplates;
1298 * gst_element_class_get_pad_template:
1299 * @element_class: a #GstElementClass to get the pad template of.
1300 * @name: the name of the #GstPadTemplate to get.
1302 * Retrieves a padtemplate from @element_class with the given name.
1303 * <note>If you use this function in the #GInstanceInitFunc of an object class
1304 * that has subclasses, make sure to pass the g_class parameter of the
1305 * #GInstanceInitFunc here.</note>
1307 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1308 * No unreferencing is necessary.
1311 gst_element_class_get_pad_template (GstElementClass * element_class,
1316 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1317 g_return_val_if_fail (name != NULL, NULL);
1319 padlist = element_class->padtemplates;
1322 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1324 if (strcmp (padtempl->name_template, name) == 0)
1327 padlist = g_list_next (padlist);
1333 static GstPadTemplate *
1334 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1337 GstPadTemplate *tmpl;
1339 tmpl = gst_element_class_get_pad_template (element_class, name);
1340 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1346 /* get a random pad on element of the given direction.
1347 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1350 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1351 GstPadDirection dir)
1353 GstPad *result = NULL;
1356 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1360 GST_OBJECT_LOCK (element);
1361 pads = element->srcpads;
1364 GST_OBJECT_LOCK (element);
1365 pads = element->sinkpads;
1368 goto wrong_direction;
1370 for (; pads; pads = g_list_next (pads)) {
1371 GstPad *pad = GST_PAD_CAST (pads->data);
1373 GST_OBJECT_LOCK (pad);
1374 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1375 GST_DEBUG_PAD_NAME (pad));
1377 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1378 /* if we require a linked pad, and it is not linked, continue the
1380 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1381 GST_DEBUG_PAD_NAME (pad));
1382 GST_OBJECT_UNLOCK (pad);
1385 /* found a pad, stop search */
1386 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1387 GST_DEBUG_PAD_NAME (pad));
1388 GST_OBJECT_UNLOCK (pad);
1394 gst_object_ref (result);
1396 GST_OBJECT_UNLOCK (element);
1400 /* ERROR handling */
1403 g_warning ("unknown pad direction %d", dir);
1409 gst_element_default_send_event (GstElement * element, GstEvent * event)
1411 gboolean result = FALSE;
1414 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1415 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1416 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1419 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1420 "pushing %s event to random %s pad %s:%s",
1421 GST_EVENT_TYPE_NAME (event),
1422 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1423 GST_DEBUG_PAD_NAME (pad));
1425 result = gst_pad_push_event (pad, event);
1426 gst_object_unref (pad);
1428 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1429 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1435 * gst_element_send_event:
1436 * @element: a #GstElement to send the event to.
1437 * @event: the #GstEvent to send to the element.
1439 * Sends an event to an element. If the element doesn't implement an
1440 * event handler, the event will be pushed on a random linked sink pad for
1441 * upstream events or a random linked source pad for downstream events.
1443 * This function takes owership of the provided event so you should
1444 * gst_event_ref() it if you want to reuse the event after this call.
1446 * Returns: %TRUE if the event was handled.
1451 gst_element_send_event (GstElement * element, GstEvent * event)
1453 GstElementClass *oclass;
1454 gboolean result = FALSE;
1456 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1457 g_return_val_if_fail (event != NULL, FALSE);
1459 oclass = GST_ELEMENT_GET_CLASS (element);
1461 GST_STATE_LOCK (element);
1462 if (oclass->send_event) {
1463 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1464 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1465 result = oclass->send_event (element, event);
1467 result = gst_element_default_send_event (element, event);
1469 GST_STATE_UNLOCK (element);
1476 * @element: a #GstElement to send the event to.
1477 * @rate: The new playback rate
1478 * @format: The format of the seek values
1479 * @flags: The optional seek flags.
1480 * @cur_type: The type and flags for the new current position
1481 * @cur: The value of the new current position
1482 * @stop_type: The type and flags for the new stop position
1483 * @stop: The value of the new stop position
1485 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1486 * the parameters. The seek event is sent to the element using
1487 * gst_element_send_event().
1489 * Returns: %TRUE if the event was handled.
1494 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1495 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1496 GstSeekType stop_type, gint64 stop)
1501 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1504 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1505 result = gst_element_send_event (element, event);
1511 * gst_element_get_query_types:
1512 * @element: a #GstElement to query
1514 * Get an array of query types from the element.
1515 * If the element doesn't implement a query types function,
1516 * the query will be forwarded to the peer of a random linked sink pad.
1518 * Returns: An array of #GstQueryType elements that should not
1519 * be freed or modified.
1523 const GstQueryType *
1524 gst_element_get_query_types (GstElement * element)
1526 GstElementClass *oclass;
1527 const GstQueryType *result = NULL;
1529 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1531 oclass = GST_ELEMENT_GET_CLASS (element);
1533 if (oclass->get_query_types) {
1534 result = oclass->get_query_types (element);
1536 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1539 GstPad *peer = gst_pad_get_peer (pad);
1542 result = gst_pad_get_query_types (peer);
1544 gst_object_unref (peer);
1546 gst_object_unref (pad);
1553 gst_element_default_query (GstElement * element, GstQuery * query)
1555 gboolean result = FALSE;
1558 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1560 result = gst_pad_query (pad, query);
1562 gst_object_unref (pad);
1564 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1566 GstPad *peer = gst_pad_get_peer (pad);
1569 result = gst_pad_query (peer, query);
1571 gst_object_unref (peer);
1573 gst_object_unref (pad);
1580 * gst_element_query:
1581 * @element: a #GstElement to perform the query on.
1582 * @query: the #GstQuery.
1584 * Performs a query on the given element.
1586 * For elements that don't implement a query handler, this function
1587 * forwards the query to a random srcpad or to the peer of a
1588 * random linked sinkpad of this element.
1590 * Returns: TRUE if the query could be performed.
1595 gst_element_query (GstElement * element, GstQuery * query)
1597 GstElementClass *oclass;
1598 gboolean result = FALSE;
1600 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1601 g_return_val_if_fail (query != NULL, FALSE);
1603 oclass = GST_ELEMENT_GET_CLASS (element);
1605 if (oclass->query) {
1606 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1607 GST_ELEMENT_NAME (element));
1608 result = oclass->query (element, query);
1610 result = gst_element_default_query (element, query);
1616 * gst_element_post_message:
1617 * @element: a #GstElement posting the message
1618 * @message: a #GstMessage to post
1620 * Post a message on the element's #GstBus. This function takes ownership of the
1621 * message; if you want to access the message after this call, you should add an
1622 * additional reference before calling.
1624 * Returns: %TRUE if the message was successfully posted. The function returns
1625 * %FALSE if the element did not have a bus.
1630 gst_element_post_message (GstElement * element, GstMessage * message)
1633 gboolean result = FALSE;
1635 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1636 g_return_val_if_fail (message != NULL, FALSE);
1638 GST_OBJECT_LOCK (element);
1641 if (G_UNLIKELY (bus == NULL))
1644 gst_object_ref (bus);
1645 GST_OBJECT_UNLOCK (element);
1647 /* we release the element lock when posting the message so that any
1648 * (synchronous) message handlers can operate on the element */
1649 result = gst_bus_post (bus, message);
1650 gst_object_unref (bus);
1657 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1658 "not posting message %p: no bus", message);
1659 GST_OBJECT_UNLOCK (element);
1660 gst_message_unref (message);
1666 * _gst_element_error_printf:
1667 * @format: the printf-like format to use, or %NULL
1669 * This function is only used internally by the gst_element_error() macro.
1671 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1676 _gst_element_error_printf (const gchar * format, ...)
1686 va_start (args, format);
1687 buffer = g_strdup_vprintf (format, args);
1693 * gst_element_message_full:
1694 * @element: a #GstElement to send message from
1695 * @type: the #GstMessageType
1696 * @domain: the GStreamer GError domain this message belongs to
1697 * @code: the GError code belonging to the domain
1698 * @text: an allocated text string to be used as a replacement for the
1699 * default message connected to code, or %NULL
1700 * @debug: an allocated debug message to be used as a replacement for the
1701 * default debugging information, or %NULL
1702 * @file: the source code file where the error was generated
1703 * @function: the source code function where the error was generated
1704 * @line: the source code line where the error was generated
1706 * Post an error, warning or info message on the bus from inside an element.
1708 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1709 * #GST_MESSAGE_INFO.
1713 void gst_element_message_full
1714 (GstElement * element, GstMessageType type,
1715 GQuark domain, gint code, gchar * text,
1716 gchar * debug, const gchar * file, const gchar * function, gint line)
1718 GError *gerror = NULL;
1722 gboolean has_debug = TRUE;
1723 GstMessage *message = NULL;
1726 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1727 g_return_if_fail (GST_IS_ELEMENT (element));
1728 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1729 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1731 /* check if we send the given text or the default error text */
1732 if ((text == NULL) || (text[0] == 0)) {
1733 /* text could have come from g_strdup_printf (""); */
1735 sent_text = gst_error_get_message (domain, code);
1739 /* construct a sent_debug with extra information from source */
1740 if ((debug == NULL) || (debug[0] == 0)) {
1741 /* debug could have come from g_strdup_printf (""); */
1745 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1747 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1748 file, line, function, name, debug);
1750 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1751 file, line, function, name);
1755 /* create gerror and post message */
1756 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1758 gerror = g_error_new_literal (domain, code, sent_text);
1761 case GST_MESSAGE_ERROR:
1763 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1765 case GST_MESSAGE_WARNING:
1766 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1769 case GST_MESSAGE_INFO:
1770 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1774 g_assert_not_reached ();
1777 gst_element_post_message (element, message);
1779 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1780 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1783 g_error_free (gerror);
1784 g_free (sent_debug);
1789 * gst_element_is_locked_state:
1790 * @element: a #GstElement.
1792 * Checks if the state of an element is locked.
1793 * If the state of an element is locked, state changes of the parent don't
1794 * affect the element.
1795 * This way you can leave currently unused elements inside bins. Just lock their
1796 * state before changing the state from #GST_STATE_NULL.
1800 * Returns: TRUE, if the element's state is locked.
1803 gst_element_is_locked_state (GstElement * element)
1807 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1809 GST_OBJECT_LOCK (element);
1810 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1811 GST_OBJECT_UNLOCK (element);
1817 * gst_element_set_locked_state:
1818 * @element: a #GstElement
1819 * @locked_state: TRUE to lock the element's state
1821 * Locks the state of an element, so state changes of the parent don't affect
1822 * this element anymore.
1826 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1827 * or the elements state-locking needed no change.
1830 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1834 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1836 GST_OBJECT_LOCK (element);
1837 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1839 if (G_UNLIKELY (old == locked_state))
1843 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1844 GST_ELEMENT_NAME (element));
1845 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1847 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1848 GST_ELEMENT_NAME (element));
1849 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1851 GST_OBJECT_UNLOCK (element);
1857 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1858 GST_ELEMENT_NAME (element), old);
1859 GST_OBJECT_UNLOCK (element);
1866 * gst_element_sync_state_with_parent:
1867 * @element: a #GstElement.
1869 * Tries to change the state of the element to the same as its parent.
1870 * If this function returns FALSE, the state of element is undefined.
1872 * Returns: TRUE, if the element's state could be synced to the parent's state.
1877 gst_element_sync_state_with_parent (GstElement * element)
1881 GstStateChangeReturn ret;
1883 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1885 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1886 GstState parent_current, parent_pending;
1888 GST_OBJECT_LOCK (parent);
1889 parent_current = GST_STATE (parent);
1890 parent_pending = GST_STATE_PENDING (parent);
1891 GST_OBJECT_UNLOCK (parent);
1893 /* set to pending if there is one, else we set it to the current state of
1895 if (parent_pending != GST_STATE_VOID_PENDING)
1896 target = parent_pending;
1898 target = parent_current;
1900 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1901 "syncing state (%s) to parent %s %s (%s, %s)",
1902 gst_element_state_get_name (GST_STATE (element)),
1903 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1904 gst_element_state_get_name (parent_current),
1905 gst_element_state_get_name (parent_pending));
1907 ret = gst_element_set_state (element, target);
1908 if (ret == GST_STATE_CHANGE_FAILURE)
1911 gst_object_unref (parent);
1915 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1922 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1923 "syncing state failed (%s)",
1924 gst_element_state_change_return_get_name (ret));
1925 gst_object_unref (parent);
1931 static GstStateChangeReturn
1932 gst_element_get_state_func (GstElement * element,
1933 GstState * state, GstState * pending, GstClockTime timeout)
1935 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1936 GstState old_pending;
1938 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1939 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1941 GST_OBJECT_LOCK (element);
1942 ret = GST_STATE_RETURN (element);
1943 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1944 gst_element_state_change_return_get_name (ret));
1946 /* we got an error, report immediately */
1947 if (ret == GST_STATE_CHANGE_FAILURE)
1950 /* we got no_preroll, report immediatly */
1951 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1954 /* no need to wait async if we are not async */
1955 if (ret != GST_STATE_CHANGE_ASYNC)
1958 old_pending = GST_STATE_PENDING (element);
1959 if (old_pending != GST_STATE_VOID_PENDING) {
1960 GTimeVal *timeval, abstimeout;
1963 if (timeout != GST_CLOCK_TIME_NONE) {
1964 glong add = timeout / 1000;
1969 /* make timeout absolute */
1970 g_get_current_time (&abstimeout);
1971 g_time_val_add (&abstimeout, add);
1972 timeval = &abstimeout;
1976 /* get cookie to detect state changes during waiting */
1977 cookie = element->state_cookie;
1979 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1980 "waiting for element to commit state");
1982 /* we have a pending state change, wait for it to complete */
1983 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1984 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1985 /* timeout triggered */
1986 ret = GST_STATE_CHANGE_ASYNC;
1988 if (cookie != element->state_cookie)
1991 /* could be success or failure */
1992 if (old_pending == GST_STATE (element)) {
1993 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1994 ret = GST_STATE_CHANGE_SUCCESS;
1996 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1997 ret = GST_STATE_CHANGE_FAILURE;
2000 /* if nothing is pending anymore we can return SUCCESS */
2001 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2002 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2003 ret = GST_STATE_CHANGE_SUCCESS;
2009 *state = GST_STATE (element);
2011 *pending = GST_STATE_PENDING (element);
2013 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2014 "state current: %s, pending: %s, result: %s",
2015 gst_element_state_get_name (GST_STATE (element)),
2016 gst_element_state_get_name (GST_STATE_PENDING (element)),
2017 gst_element_state_change_return_get_name (ret));
2018 GST_OBJECT_UNLOCK (element);
2025 *state = GST_STATE_VOID_PENDING;
2027 *pending = GST_STATE_VOID_PENDING;
2029 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2031 GST_OBJECT_UNLOCK (element);
2033 return GST_STATE_CHANGE_FAILURE;
2038 * gst_element_get_state:
2039 * @element: a #GstElement to get the state of.
2040 * @state: (out): a pointer to #GstState to hold the state. Can be %NULL.
2041 * @pending: (out): a pointer to #GstState to hold the pending state.
2043 * @timeout: a #GstClockTime to specify the timeout for an async
2044 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2046 * Gets the state of the element.
2048 * For elements that performed an ASYNC state change, as reported by
2049 * gst_element_set_state(), this function will block up to the
2050 * specified timeout value for the state change to complete.
2051 * If the element completes the state change or goes into
2052 * an error, this function returns immediately with a return value of
2053 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2055 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2056 * returns the current and pending state immediately.
2058 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2059 * successfully changed its state but is not able to provide data yet.
2060 * This mostly happens for live sources that only produce data in
2061 * %GST_STATE_PLAYING. While the state change return is equivalent to
2062 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2063 * some sink elements might not be able to complete their state change because
2064 * an element is not producing data to complete the preroll. When setting the
2065 * element to playing, the preroll will complete and playback will start.
2067 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2068 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2069 * element is still performing a state change or
2070 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2074 GstStateChangeReturn
2075 gst_element_get_state (GstElement * element,
2076 GstState * state, GstState * pending, GstClockTime timeout)
2078 GstElementClass *oclass;
2079 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2081 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2083 oclass = GST_ELEMENT_GET_CLASS (element);
2085 if (oclass->get_state)
2086 result = (oclass->get_state) (element, state, pending, timeout);
2092 * gst_element_abort_state:
2093 * @element: a #GstElement to abort the state of.
2095 * Abort the state change of the element. This function is used
2096 * by elements that do asynchronous state changes and find out
2097 * something is wrong.
2099 * This function should be called with the STATE_LOCK held.
2104 gst_element_abort_state (GstElement * element)
2108 #ifndef GST_DISABLE_GST_DEBUG
2112 g_return_if_fail (GST_IS_ELEMENT (element));
2114 GST_OBJECT_LOCK (element);
2115 pending = GST_STATE_PENDING (element);
2117 if (pending == GST_STATE_VOID_PENDING ||
2118 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2119 goto nothing_aborted;
2121 #ifndef GST_DISABLE_GST_DEBUG
2122 old_state = GST_STATE (element);
2124 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2125 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2126 gst_element_state_get_name (pending));
2130 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2132 GST_STATE_BROADCAST (element);
2133 GST_OBJECT_UNLOCK (element);
2139 GST_OBJECT_UNLOCK (element);
2145 * gst_element_continue_state:
2146 * @element: a #GstElement to continue the state change of.
2147 * @ret: The previous state return value
2149 * Commit the state change of the element and proceed to the next
2150 * pending state if any. This function is used
2151 * by elements that do asynchronous state changes.
2152 * The core will normally call this method automatically when an
2153 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2155 * If after calling this method the element still has not reached
2156 * the pending state, the next state change is performed.
2158 * This method is used internally and should normally not be called by plugins
2161 * Returns: The result of the commit state change.
2165 GstStateChangeReturn
2166 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2168 GstStateChangeReturn old_ret;
2169 GstState old_state, old_next;
2170 GstState current, next, pending;
2171 GstMessage *message;
2172 GstStateChange transition;
2174 GST_OBJECT_LOCK (element);
2175 old_ret = GST_STATE_RETURN (element);
2176 GST_STATE_RETURN (element) = ret;
2177 pending = GST_STATE_PENDING (element);
2179 /* check if there is something to commit */
2180 if (pending == GST_STATE_VOID_PENDING)
2181 goto nothing_pending;
2183 old_state = GST_STATE (element);
2184 /* this is the state we should go to next */
2185 old_next = GST_STATE_NEXT (element);
2186 /* update current state */
2187 current = GST_STATE (element) = old_next;
2189 /* see if we reached the final state */
2190 if (pending == current)
2193 next = GST_STATE_GET_NEXT (current, pending);
2194 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2196 GST_STATE_NEXT (element) = next;
2198 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2199 GST_OBJECT_UNLOCK (element);
2201 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2202 "committing state from %s to %s, pending %s, next %s",
2203 gst_element_state_get_name (old_state),
2204 gst_element_state_get_name (old_next),
2205 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2207 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2208 old_state, old_next, pending);
2209 gst_element_post_message (element, message);
2211 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2212 "continue state change %s to %s, final %s",
2213 gst_element_state_get_name (current),
2214 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2216 ret = gst_element_change_state (element, transition);
2222 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2223 GST_OBJECT_UNLOCK (element);
2228 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2229 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2231 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2232 "completed state change to %s", gst_element_state_get_name (pending));
2233 GST_OBJECT_UNLOCK (element);
2235 /* don't post silly messages with the same state. This can happen
2236 * when an element state is changed to what it already was. For bins
2237 * this can be the result of a lost state, which we check with the
2238 * previous return value.
2239 * We do signal the cond though as a _get_state() might be blocking
2241 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2242 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2243 "posting state-changed %s to %s",
2244 gst_element_state_get_name (old_state),
2245 gst_element_state_get_name (old_next));
2247 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2248 old_next, GST_STATE_VOID_PENDING);
2249 gst_element_post_message (element, message);
2252 GST_STATE_BROADCAST (element);
2259 * gst_element_lost_state_full:
2260 * @element: a #GstElement the state is lost of
2261 * @new_base_time: if a new base time should be distributed
2263 * Brings the element to the lost state. The current state of the
2264 * element is copied to the pending state so that any call to
2265 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2267 * An ASYNC_START message is posted with indication to distribute a new
2268 * base_time to the element when @new_base_time is %TRUE.
2269 * If the element was PLAYING, it will go to PAUSED. The element
2270 * will be restored to its PLAYING state by the parent pipeline when it
2273 * This is mostly used for elements that lost their preroll buffer
2274 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2275 * they will go to their pending state again when a new preroll buffer is
2276 * queued. This function can only be called when the element is currently
2277 * not in error or an async state change.
2279 * This function is used internally and should normally not be called from
2280 * plugins or applications.
2287 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2289 GstState old_state, new_state;
2290 GstMessage *message;
2292 g_return_if_fail (GST_IS_ELEMENT (element));
2294 GST_OBJECT_LOCK (element);
2295 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2298 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2299 goto only_async_start;
2301 old_state = GST_STATE (element);
2303 /* when we were PLAYING, the new state is PAUSED. We will also not
2304 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2305 * when we preroll. */
2306 if (old_state > GST_STATE_PAUSED)
2307 new_state = GST_STATE_PAUSED;
2309 new_state = old_state;
2311 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2312 "lost state of %s to %s", gst_element_state_get_name (old_state),
2313 gst_element_state_get_name (new_state));
2315 GST_STATE (element) = new_state;
2316 GST_STATE_NEXT (element) = new_state;
2317 GST_STATE_PENDING (element) = new_state;
2318 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2320 GST_ELEMENT_START_TIME (element) = 0;
2321 GST_OBJECT_UNLOCK (element);
2323 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2324 new_state, new_state, new_state);
2325 gst_element_post_message (element, message);
2328 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2329 gst_element_post_message (element, message);
2335 GST_OBJECT_UNLOCK (element);
2340 GST_OBJECT_UNLOCK (element);
2342 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2343 gst_element_post_message (element, message);
2349 * gst_element_lost_state:
2350 * @element: a #GstElement the state is lost of
2352 * Brings the element to the lost state. This function calls
2353 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2355 * This function is used internally and should normally not be called from
2356 * plugins or applications.
2361 gst_element_lost_state (GstElement * element)
2363 gst_element_lost_state_full (element, TRUE);
2367 * gst_element_set_state:
2368 * @element: a #GstElement to change state of.
2369 * @state: the element's new #GstState.
2371 * Sets the state of the element. This function will try to set the
2372 * requested state by going through all the intermediary states and calling
2373 * the class's state change function for each.
2375 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2376 * element will perform the remainder of the state change asynchronously in
2378 * An application can use gst_element_get_state() to wait for the completion
2379 * of the state change or it can wait for a state change message on the bus.
2381 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2382 * #GST_STATE_CHANGE_ASYNC.
2384 * Returns: Result of the state change using #GstStateChangeReturn.
2388 GstStateChangeReturn
2389 gst_element_set_state (GstElement * element, GstState state)
2391 GstElementClass *oclass;
2392 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2394 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2396 oclass = GST_ELEMENT_GET_CLASS (element);
2398 if (oclass->set_state)
2399 result = (oclass->set_state) (element, state);
2405 * default set state function, calculates the next state based
2406 * on current state and calls the change_state function
2408 static GstStateChangeReturn
2409 gst_element_set_state_func (GstElement * element, GstState state)
2411 GstState current, next, old_pending;
2412 GstStateChangeReturn ret;
2413 GstStateChange transition;
2414 GstStateChangeReturn old_ret;
2416 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2418 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2419 gst_element_state_get_name (state));
2421 /* state lock is taken to protect the set_state() and get_state()
2422 * procedures, it does not lock any variables. */
2423 GST_STATE_LOCK (element);
2425 /* now calculate how to get to the new state */
2426 GST_OBJECT_LOCK (element);
2427 old_ret = GST_STATE_RETURN (element);
2428 /* previous state change returned an error, remove all pending
2429 * and next states */
2430 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2431 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2432 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2433 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2436 current = GST_STATE (element);
2437 next = GST_STATE_NEXT (element);
2438 old_pending = GST_STATE_PENDING (element);
2440 /* this is the (new) state we should go to. TARGET is the last state we set on
2442 if (state != GST_STATE_TARGET (element)) {
2443 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2444 "setting target state to %s", gst_element_state_get_name (state));
2445 GST_STATE_TARGET (element) = state;
2446 /* increment state cookie so that we can track each state change. We only do
2447 * this if this is actually a new state change. */
2448 element->state_cookie++;
2450 GST_STATE_PENDING (element) = state;
2452 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2453 "current %s, old_pending %s, next %s, old return %s",
2454 gst_element_state_get_name (current),
2455 gst_element_state_get_name (old_pending),
2456 gst_element_state_get_name (next),
2457 gst_element_state_change_return_get_name (old_ret));
2459 /* if the element was busy doing a state change, we just update the
2460 * target state, it'll get to it async then. */
2461 if (old_pending != GST_STATE_VOID_PENDING) {
2462 /* upwards state change will happen ASYNC */
2463 if (old_pending <= state)
2465 /* element is going to this state already */
2466 else if (next == state)
2468 /* element was performing an ASYNC upward state change and
2469 * we request to go downward again. Start from the next pending
2471 else if (next > state
2472 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2476 next = GST_STATE_GET_NEXT (current, state);
2477 /* now we store the next state */
2478 GST_STATE_NEXT (element) = next;
2479 /* mark busy, we need to check that there is actually a state change
2480 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2481 * the default element change_state function has no way to know what the
2482 * old value was... could consider this a FIXME...*/
2483 if (current != next)
2484 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2486 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2488 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2489 "%s: setting state from %s to %s",
2490 (next != state ? "intermediate" : "final"),
2491 gst_element_state_get_name (current), gst_element_state_get_name (next));
2493 /* now signal any waiters, they will error since the cookie was incremented */
2494 GST_STATE_BROADCAST (element);
2496 GST_OBJECT_UNLOCK (element);
2498 ret = gst_element_change_state (element, transition);
2500 GST_STATE_UNLOCK (element);
2502 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2503 gst_element_state_change_return_get_name (ret));
2509 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2510 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2511 "element was busy with async state change");
2512 GST_OBJECT_UNLOCK (element);
2514 GST_STATE_UNLOCK (element);
2516 return GST_STATE_CHANGE_ASYNC;
2521 * gst_element_change_state:
2522 * @element: a #GstElement
2523 * @transition: the requested transition
2525 * Perform @transition on @element.
2527 * This function must be called with STATE_LOCK held and is mainly used
2530 * Returns: the #GstStateChangeReturn of the state transition.
2532 GstStateChangeReturn
2533 gst_element_change_state (GstElement * element, GstStateChange transition)
2535 GstElementClass *oclass;
2536 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2538 oclass = GST_ELEMENT_GET_CLASS (element);
2540 /* call the state change function so it can set the state */
2541 if (oclass->change_state)
2542 ret = (oclass->change_state) (element, transition);
2544 ret = GST_STATE_CHANGE_FAILURE;
2547 case GST_STATE_CHANGE_FAILURE:
2548 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2549 "have FAILURE change_state return");
2550 /* state change failure */
2551 gst_element_abort_state (element);
2553 case GST_STATE_CHANGE_ASYNC:
2557 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2558 "element will change state ASYNC");
2560 target = GST_STATE_TARGET (element);
2562 if (target > GST_STATE_READY)
2565 /* else we just continue the state change downwards */
2566 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2567 "forcing commit state %s <= %s",
2568 gst_element_state_get_name (target),
2569 gst_element_state_get_name (GST_STATE_READY));
2571 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2574 case GST_STATE_CHANGE_SUCCESS:
2575 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2576 "element changed state SUCCESS");
2577 /* we can commit the state now which will proceeed to
2579 ret = gst_element_continue_state (element, ret);
2581 case GST_STATE_CHANGE_NO_PREROLL:
2582 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2583 "element changed state NO_PREROLL");
2584 /* we can commit the state now which will proceeed to
2586 ret = gst_element_continue_state (element, ret);
2589 goto invalid_return;
2592 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2597 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2605 GST_OBJECT_LOCK (element);
2606 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2607 g_critical ("%s: unknown return value %d from a state change function",
2608 GST_ELEMENT_NAME (element), ret);
2610 /* we are in error now */
2611 ret = GST_STATE_CHANGE_FAILURE;
2612 GST_STATE_RETURN (element) = ret;
2613 GST_OBJECT_UNLOCK (element);
2619 /* gst_iterator_fold functions for pads_activate
2620 * Note how we don't stop the iterator when we fail an activation. This is
2621 * probably a FIXME since when one pad activation fails, we don't want to
2622 * continue our state change. */
2624 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2626 if (!gst_pad_set_active (pad, *active))
2627 g_value_set_boolean (ret, FALSE);
2629 /* unref the object that was reffed for us by _fold */
2630 gst_object_unref (pad);
2634 /* set the caps on the pad to NULL */
2636 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2638 gst_pad_set_caps (pad, NULL);
2639 gst_object_unref (pad);
2643 /* returns false on error or early cutout (will never happen because the fold
2644 * function always returns TRUE, see FIXME above) of the fold, true if all
2645 * pads in @iter were (de)activated successfully. */
2647 iterator_activate_fold_with_resync (GstIterator * iter,
2648 GstIteratorFoldFunction func, gpointer user_data)
2650 GstIteratorResult ires;
2653 /* no need to unset this later, it's just a boolean */
2654 g_value_init (&ret, G_TYPE_BOOLEAN);
2655 g_value_set_boolean (&ret, TRUE);
2658 ires = gst_iterator_fold (iter, func, &ret, user_data);
2660 case GST_ITERATOR_RESYNC:
2661 /* need to reset the result again */
2662 g_value_set_boolean (&ret, TRUE);
2663 gst_iterator_resync (iter);
2665 case GST_ITERATOR_DONE:
2666 /* all pads iterated, return collected value */
2669 /* iterator returned _ERROR or premature end with _OK,
2670 * mark an error and exit */
2671 g_value_set_boolean (&ret, FALSE);
2676 /* return collected value */
2677 return g_value_get_boolean (&ret);
2681 negotiable_pads (GstPad * pad, GValue * ret, gboolean * active)
2683 if (!gst_pad_set_negotiable (pad, *active))
2684 g_value_set_boolean (ret, FALSE);
2686 /* unref the object that was reffed for us by _fold */
2687 gst_object_unref (pad);
2691 /* is called with STATE_LOCK */
2693 gst_element_pads_negotiable (GstElement * element, gboolean negotiable)
2698 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2699 "pads_negotiable with negotiable %d", negotiable);
2701 /* clear the caps on all pads, this should never fail */
2702 iter = gst_element_iterate_pads (element);
2704 iterator_activate_fold_with_resync (iter,
2705 (GstIteratorFoldFunction) negotiable_pads, &negotiable);
2706 gst_iterator_free (iter);
2707 if (G_UNLIKELY (!res))
2708 goto negotiable_failed;
2710 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2711 "pads_negotiable successful");
2718 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2719 "failed to set pads to 'negotiable'");
2725 /* is called with STATE_LOCK
2727 * Pads are activated from source pads to sinkpads.
2730 gst_element_pads_activate (GstElement * element, gboolean active)
2735 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2736 "pads_activate with active %d", active);
2738 iter = gst_element_iterate_src_pads (element);
2740 iterator_activate_fold_with_resync (iter,
2741 (GstIteratorFoldFunction) activate_pads, &active);
2742 gst_iterator_free (iter);
2743 if (G_UNLIKELY (!res))
2746 iter = gst_element_iterate_sink_pads (element);
2748 iterator_activate_fold_with_resync (iter,
2749 (GstIteratorFoldFunction) activate_pads, &active);
2750 gst_iterator_free (iter);
2751 if (G_UNLIKELY (!res))
2755 /* clear the caps on all pads, this should never fail */
2756 iter = gst_element_iterate_pads (element);
2758 iterator_activate_fold_with_resync (iter,
2759 (GstIteratorFoldFunction) clear_caps, &active);
2760 gst_iterator_free (iter);
2761 if (G_UNLIKELY (!res))
2765 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2766 "pads_activate successful");
2773 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2774 "source pads_activate failed");
2779 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2780 "sink pads_activate failed");
2785 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2786 "failed to clear caps on pads");
2791 /* is called with STATE_LOCK */
2792 static GstStateChangeReturn
2793 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2795 GstState state, next;
2796 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2799 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2801 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2802 next = GST_STATE_TRANSITION_NEXT (transition);
2804 /* if the element already is in the given state, we just return success */
2805 if (next == GST_STATE_VOID_PENDING || state == next)
2808 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2809 "default handler tries setting state from %s to %s (%04x)",
2810 gst_element_state_get_name (state),
2811 gst_element_state_get_name (next), transition);
2813 switch (transition) {
2814 case GST_STATE_CHANGE_NULL_TO_READY:
2815 if (!gst_element_pads_negotiable (element, TRUE)) {
2816 result = GST_STATE_CHANGE_FAILURE;
2819 case GST_STATE_CHANGE_READY_TO_PAUSED:
2820 if (!gst_element_pads_activate (element, TRUE)) {
2821 result = GST_STATE_CHANGE_FAILURE;
2824 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2826 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2828 case GST_STATE_CHANGE_PAUSED_TO_READY:
2829 case GST_STATE_CHANGE_READY_TO_NULL:
2830 /* deactivate pads in both cases, since they are activated on
2831 ready->paused but the element might not have made it to paused */
2832 if (!gst_element_pads_activate (element, FALSE)) {
2833 result = GST_STATE_CHANGE_FAILURE;
2835 gst_element_set_base_time (element, 0);
2837 gst_element_pads_negotiable (element, FALSE);
2839 /* In null state release the reference to the clock */
2840 GST_OBJECT_LOCK (element);
2841 clock_p = &element->clock;
2842 gst_object_replace ((GstObject **) clock_p, NULL);
2843 GST_OBJECT_UNLOCK (element);
2846 /* this will catch real but unhandled state changes;
2847 * can only be caused by:
2848 * - a new state was added
2849 * - somehow the element was asked to jump across an intermediate state
2851 g_warning ("Unhandled state change from %s to %s",
2852 gst_element_state_get_name (state),
2853 gst_element_state_get_name (next));
2860 GST_OBJECT_LOCK (element);
2861 result = GST_STATE_RETURN (element);
2862 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2863 "element is already in the %s state",
2864 gst_element_state_get_name (state));
2865 GST_OBJECT_UNLOCK (element);
2872 * gst_element_get_factory:
2873 * @element: a #GstElement to request the element factory of.
2875 * Retrieves the factory that was used to create this element.
2877 * Returns: the #GstElementFactory used for creating this element.
2878 * no refcounting is needed.
2881 gst_element_get_factory (GstElement * element)
2883 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2885 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2889 gst_element_dispose (GObject * object)
2891 GstElement *element = GST_ELEMENT_CAST (object);
2895 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2897 if (GST_STATE (element) != GST_STATE_NULL)
2900 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2901 "removing %d pads", g_list_length (element->pads));
2902 /* first we break all our links with the outside */
2903 while (element->pads && element->pads->data) {
2904 /* don't call _remove_pad with NULL */
2905 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2907 if (G_UNLIKELY (element->pads != NULL)) {
2908 g_critical ("could not remove pads from element %s",
2909 GST_STR_NULL (GST_OBJECT_NAME (object)));
2912 GST_OBJECT_LOCK (element);
2913 clock_p = &element->clock;
2914 bus_p = &element->bus;
2915 gst_object_replace ((GstObject **) clock_p, NULL);
2916 gst_object_replace ((GstObject **) bus_p, NULL);
2917 GST_OBJECT_UNLOCK (element);
2919 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2921 G_OBJECT_CLASS (parent_class)->dispose (object);
2930 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2932 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2934 "You need to explicitly set elements to the NULL state before\n"
2935 "dropping the final reference, to allow them to clean up.\n"
2936 "This problem may also be caused by a refcounting bug in the\n"
2937 "application or some element.\n",
2938 GST_OBJECT_NAME (element),
2939 gst_element_state_get_name (GST_STATE (element)),
2940 is_locked ? " (locked)" : "");
2946 gst_element_finalize (GObject * object)
2948 GstElement *element = GST_ELEMENT_CAST (object);
2950 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2952 GST_STATE_LOCK (element);
2953 if (element->state_cond)
2954 g_cond_free (element->state_cond);
2955 element->state_cond = NULL;
2956 GST_STATE_UNLOCK (element);
2957 g_static_rec_mutex_free (element->state_lock);
2958 g_slice_free (GStaticRecMutex, element->state_lock);
2959 element->state_lock = NULL;
2961 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2963 G_OBJECT_CLASS (parent_class)->finalize (object);
2966 #ifndef GST_DISABLE_LOADSAVE
2968 * gst_element_save_thyself:
2969 * @element: a #GstElement to save.
2970 * @parent: the xml parent node.
2972 * Saves the element as part of the given XML structure.
2974 * Returns: the new #xmlNodePtr.
2977 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2980 GstElementClass *oclass;
2981 GParamSpec **specs, *spec;
2984 GValue value = { 0, };
2985 GstElement *element;
2987 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2989 element = GST_ELEMENT_CAST (object);
2991 oclass = GST_ELEMENT_GET_CLASS (element);
2993 xmlNewChild (parent, NULL, (xmlChar *) "name",
2994 (xmlChar *) GST_ELEMENT_NAME (element));
2996 if (oclass->elementfactory != NULL) {
2997 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2999 xmlNewChild (parent, NULL, (xmlChar *) "type",
3000 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
3004 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
3006 for (i = 0; i < nspecs; i++) {
3008 if (spec->flags & G_PARAM_READABLE) {
3012 g_value_init (&value, spec->value_type);
3014 g_object_get_property (G_OBJECT (element), spec->name, &value);
3015 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
3016 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
3018 if (G_IS_PARAM_SPEC_STRING (spec))
3019 contents = g_value_dup_string (&value);
3020 else if (G_IS_PARAM_SPEC_ENUM (spec))
3021 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
3022 else if (G_IS_PARAM_SPEC_INT64 (spec))
3023 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
3024 g_value_get_int64 (&value));
3025 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
3026 if (g_value_get_boxed (&value) != NULL) {
3027 contents = g_strdup_value_contents (&value);
3029 contents = g_strdup ("NULL");
3032 contents = g_strdup_value_contents (&value);
3034 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
3037 g_value_unset (&value);
3043 pads = g_list_last (GST_ELEMENT_PADS (element));
3046 GstPad *pad = GST_PAD_CAST (pads->data);
3048 /* figure out if it's a direct pad or a ghostpad */
3049 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
3050 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
3052 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
3054 pads = g_list_previous (pads);
3061 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3063 xmlNodePtr children;
3064 GstElement *element;
3066 gchar *value = NULL;
3068 element = GST_ELEMENT_CAST (object);
3069 g_return_if_fail (element != NULL);
3072 children = self->xmlChildrenNode;
3074 if (!strcmp ((char *) children->name, "param")) {
3075 xmlNodePtr child = children->xmlChildrenNode;
3078 if (!strcmp ((char *) child->name, "name")) {
3079 name = (gchar *) xmlNodeGetContent (child);
3080 } else if (!strcmp ((char *) child->name, "value")) {
3081 value = (gchar *) xmlNodeGetContent (child);
3083 child = child->next;
3085 /* FIXME: can this just be g_object_set ? */
3086 gst_util_set_object_arg (G_OBJECT (element), name, value);
3087 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3091 children = children->next;
3095 children = self->xmlChildrenNode;
3097 if (!strcmp ((char *) children->name, "pad")) {
3098 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3100 children = children->next;
3103 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3104 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3106 #endif /* GST_DISABLE_LOADSAVE */
3109 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3113 g_return_if_fail (GST_IS_ELEMENT (element));
3115 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3117 GST_OBJECT_LOCK (element);
3118 bus_p = &GST_ELEMENT_BUS (element);
3119 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3120 GST_OBJECT_UNLOCK (element);
3124 * gst_element_set_bus:
3125 * @element: a #GstElement to set the bus of.
3126 * @bus: the #GstBus to set.
3128 * Sets the bus of the element. Increases the refcount on the bus.
3129 * For internal use only, unless you're testing elements.
3134 gst_element_set_bus (GstElement * element, GstBus * bus)
3136 GstElementClass *oclass;
3138 g_return_if_fail (GST_IS_ELEMENT (element));
3140 oclass = GST_ELEMENT_GET_CLASS (element);
3142 if (oclass->set_bus)
3143 oclass->set_bus (element, bus);
3147 * gst_element_get_bus:
3148 * @element: a #GstElement to get the bus of.
3150 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3151 * bus for the application.
3153 * Returns: the element's #GstBus. unref after usage.
3158 gst_element_get_bus (GstElement * element)
3160 GstBus *result = NULL;
3162 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3164 GST_OBJECT_LOCK (element);
3165 if ((result = GST_ELEMENT_BUS (element)))
3166 gst_object_ref (result);
3167 GST_OBJECT_UNLOCK (element);
3169 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,