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)
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 GST_OBJECT_UNLOCK (pad);
702 /* then check to see if there's already a pad by that name here */
703 GST_OBJECT_LOCK (element);
704 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
707 /* try to set the pad's parent */
708 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
709 GST_OBJECT_CAST (element))))
712 /* check for flushing pads */
713 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
714 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
715 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
716 "use gst_pad_set_active(pad,TRUE) before adding it.",
717 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
719 GST_OBJECT_LOCK (pad);
720 GST_PAD_UNSET_FLUSHING (pad);
721 GST_OBJECT_UNLOCK (pad);
726 /* add it to the list */
727 switch (gst_pad_get_direction (pad)) {
729 element->srcpads = g_list_prepend (element->srcpads, pad);
730 element->numsrcpads++;
733 element->sinkpads = g_list_prepend (element->sinkpads, pad);
734 element->numsinkpads++;
739 element->pads = g_list_prepend (element->pads, pad);
741 element->pads_cookie++;
742 GST_OBJECT_UNLOCK (element);
744 /* emit the PAD_ADDED signal */
745 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
752 g_critical ("Padname %s is not unique in element %s, not adding",
753 pad_name, GST_ELEMENT_NAME (element));
754 GST_OBJECT_UNLOCK (element);
761 ("Pad %s already has parent when trying to add to element %s",
762 pad_name, GST_ELEMENT_NAME (element));
763 GST_OBJECT_UNLOCK (element);
769 GST_OBJECT_LOCK (pad);
771 ("Trying to add pad %s to element %s, but it has no direction",
772 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
773 GST_OBJECT_UNLOCK (pad);
774 GST_OBJECT_UNLOCK (element);
780 * gst_element_remove_pad:
781 * @element: a #GstElement to remove pad from.
782 * @pad: the #GstPad to remove from the element.
784 * Removes @pad from @element. @pad will be destroyed if it has not been
785 * referenced elsewhere using gst_object_unparent().
787 * This function is used by plugin developers and should not be used
788 * by applications. Pads that were dynamically requested from elements
789 * with gst_element_get_request_pad() should be released with the
790 * gst_element_release_request_pad() function instead.
792 * Pads are not automatically deactivated so elements should perform the needed
793 * steps to deactivate the pad in case this pad is removed in the PAUSED or
794 * PLAYING state. See gst_pad_set_active() for more information about
797 * The pad and the element should be unlocked when calling this function.
799 * This function will emit the #GstElement::pad-removed signal on the element.
801 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
802 * pad does not belong to the provided element.
807 gst_element_remove_pad (GstElement * element, GstPad * pad)
811 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
812 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
814 /* locking pad to look at the name and parent */
815 GST_OBJECT_LOCK (pad);
816 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
817 GST_STR_NULL (GST_PAD_NAME (pad)));
819 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
821 GST_OBJECT_UNLOCK (pad);
824 if ((peer = gst_pad_get_peer (pad))) {
825 /* window for MT unsafeness, someone else could unlink here
826 * and then we call unlink with wrong pads. The unlink
827 * function would catch this and safely return failed. */
828 if (GST_PAD_IS_SRC (pad))
829 gst_pad_unlink (pad, peer);
831 gst_pad_unlink (peer, pad);
833 gst_object_unref (peer);
836 GST_OBJECT_LOCK (element);
837 /* remove it from the list */
838 switch (gst_pad_get_direction (pad)) {
840 element->srcpads = g_list_remove (element->srcpads, pad);
841 element->numsrcpads--;
844 element->sinkpads = g_list_remove (element->sinkpads, pad);
845 element->numsinkpads--;
848 g_critical ("Removing pad without direction???");
851 element->pads = g_list_remove (element->pads, pad);
853 element->pads_cookie++;
854 GST_OBJECT_UNLOCK (element);
856 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
857 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
859 gst_object_unparent (GST_OBJECT_CAST (pad));
866 /* FIXME, locking order? */
867 GST_OBJECT_LOCK (element);
868 g_critical ("Padname %s:%s does not belong to element %s when removing",
869 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
870 GST_OBJECT_UNLOCK (element);
871 GST_OBJECT_UNLOCK (pad);
877 * gst_element_no_more_pads:
878 * @element: a #GstElement
880 * Use this function to signal that the element does not expect any more pads
881 * to show up in the current pipeline. This function should be called whenever
882 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
883 * pad templates use this in combination with autopluggers to figure out that
884 * the element is done initializing its pads.
886 * This function emits the #GstElement::no-more-pads signal.
891 gst_element_no_more_pads (GstElement * element)
893 g_return_if_fail (GST_IS_ELEMENT (element));
895 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
899 pad_compare_name (GstPad * pad1, const gchar * name)
903 GST_OBJECT_LOCK (pad1);
904 result = strcmp (GST_PAD_NAME (pad1), name);
905 GST_OBJECT_UNLOCK (pad1);
911 * gst_element_get_static_pad:
912 * @element: a #GstElement to find a static pad of.
913 * @name: the name of the static #GstPad to retrieve.
915 * Retrieves a pad from @element by name. This version only retrieves
916 * already-existing (i.e. 'static') pads.
918 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
924 gst_element_get_static_pad (GstElement * element, const gchar * name)
927 GstPad *result = NULL;
929 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
930 g_return_val_if_fail (name != NULL, NULL);
932 GST_OBJECT_LOCK (element);
934 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
936 result = GST_PAD_CAST (find->data);
937 gst_object_ref (result);
940 if (result == NULL) {
941 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
942 name, GST_ELEMENT_NAME (element));
944 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
945 GST_ELEMENT_NAME (element), name);
947 GST_OBJECT_UNLOCK (element);
953 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
956 GstPad *newpad = NULL;
957 GstElementClass *oclass;
959 oclass = GST_ELEMENT_GET_CLASS (element);
961 if (oclass->request_new_pad)
962 newpad = (oclass->request_new_pad) (element, templ, name);
965 gst_object_ref (newpad);
971 * gst_element_get_request_pad:
972 * @element: a #GstElement to find a request pad of.
973 * @name: the name of the request #GstPad to retrieve.
975 * Retrieves a pad from the element by name. This version only retrieves
976 * request pads. The pad should be released with
977 * gst_element_release_request_pad().
979 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
982 gst_element_get_request_pad (GstElement * element, const gchar * name)
984 GstPadTemplate *templ = NULL;
986 const gchar *req_name = NULL;
987 gboolean templ_found = FALSE;
990 gchar *str, *endptr = NULL;
991 GstElementClass *class;
993 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
994 g_return_val_if_fail (name != NULL, NULL);
996 class = GST_ELEMENT_GET_CLASS (element);
998 /* if the name contains a %, we assume it's the complete template name. Get
999 * the template and try to get a pad */
1000 if (strstr (name, "%")) {
1001 templ = gst_element_class_get_request_pad_template (class, name);
1006 /* there is no % in the name, try to find a matching template */
1007 list = class->padtemplates;
1008 while (!templ_found && list) {
1009 templ = (GstPadTemplate *) list->data;
1010 if (templ->presence == GST_PAD_REQUEST) {
1011 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1012 templ->name_template);
1013 /* see if we find an exact match */
1014 if (strcmp (name, templ->name_template) == 0) {
1019 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1020 and %d, occurring at the end of the name_template, are the only
1022 else if ((str = strchr (templ->name_template, '%'))
1023 && strncmp (templ->name_template, name,
1024 str - templ->name_template) == 0
1025 && strlen (name) > str - templ->name_template) {
1026 data = name + (str - templ->name_template);
1027 if (*(str + 1) == 'd') {
1029 (void) strtol (data, &endptr, 10);
1030 if (endptr && *endptr == '\0') {
1050 pad = gst_element_request_pad (element, templ, req_name);
1056 * gst_element_get_pad:
1057 * @element: a #GstElement.
1058 * @name: the name of the pad to retrieve.
1060 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1061 * first, then gst_element_get_request_pad().
1063 * Deprecated: This function is deprecated as it's unclear if the reference
1064 * to the result pad should be released with gst_object_unref() in case of a static pad
1065 * or gst_element_release_request_pad() in case of a request pad.
1066 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1068 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1069 * depending on the type of the pad.
1071 #ifndef GST_REMOVE_DEPRECATED
1072 #ifdef GST_DISABLE_DEPRECATED
1073 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1076 gst_element_get_pad (GstElement * element, const gchar * name)
1080 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1081 g_return_val_if_fail (name != NULL, NULL);
1083 pad = gst_element_get_static_pad (element, name);
1085 pad = gst_element_get_request_pad (element, name);
1089 #endif /* GST_REMOVE_DEPRECATED */
1091 static GstIteratorItem
1092 iterate_pad (GstIterator * it, GstPad * pad)
1094 gst_object_ref (pad);
1095 return GST_ITERATOR_ITEM_PASS;
1098 static GstIterator *
1099 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1101 GstIterator *result;
1103 GST_OBJECT_LOCK (element);
1104 gst_object_ref (element);
1105 result = gst_iterator_new_list (GST_TYPE_PAD,
1106 GST_OBJECT_GET_LOCK (element),
1107 &element->pads_cookie,
1110 (GstIteratorItemFunction) iterate_pad,
1111 (GstIteratorDisposeFunction) gst_object_unref);
1112 GST_OBJECT_UNLOCK (element);
1118 * gst_element_iterate_pads:
1119 * @element: a #GstElement to iterate pads of.
1121 * Retrieves an iterattor of @element's pads. The iterator should
1122 * be freed after usage.
1124 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1129 gst_element_iterate_pads (GstElement * element)
1131 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1133 return gst_element_iterate_pad_list (element, &element->pads);
1137 * gst_element_iterate_src_pads:
1138 * @element: a #GstElement.
1140 * Retrieves an iterator of @element's source pads.
1142 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1147 gst_element_iterate_src_pads (GstElement * element)
1149 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1151 return gst_element_iterate_pad_list (element, &element->srcpads);
1155 * gst_element_iterate_sink_pads:
1156 * @element: a #GstElement.
1158 * Retrieves an iterator of @element's sink pads.
1160 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1165 gst_element_iterate_sink_pads (GstElement * element)
1167 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1169 return gst_element_iterate_pad_list (element, &element->sinkpads);
1173 * gst_element_class_add_pad_template:
1174 * @klass: the #GstElementClass to add the pad template to.
1175 * @templ: a #GstPadTemplate to add to the element class.
1177 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1178 * functions of classes.
1181 gst_element_class_add_pad_template (GstElementClass * klass,
1182 GstPadTemplate * templ)
1184 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1185 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1187 /* FIXME 0.11: allow replacing the pad templates by
1188 * calling this with the same name as an already existing pad
1189 * template. For this we _must_ _not_ ref the added pad template
1190 * a second time and _must_ document that this function takes
1191 * ownership of the pad template. Otherwise we will leak pad templates
1192 * or the caller unref's the pad template and it disappears */
1193 /* avoid registering pad templates with the same name */
1194 g_return_if_fail (gst_element_class_get_pad_template (klass,
1195 templ->name_template) == NULL);
1197 klass->padtemplates = g_list_append (klass->padtemplates,
1198 gst_object_ref (templ));
1199 klass->numpadtemplates++;
1203 * gst_element_class_set_details:
1204 * @klass: class to set details for
1205 * @details: details to set
1207 * Sets the detailed information for a #GstElementClass.
1208 * <note>This function is for use in _base_init functions only.</note>
1210 * The @details are copied.
1212 * Deprecated: Use gst_element_class_set_details_simple() instead.
1214 #ifndef GST_REMOVE_DEPRECATED
1215 #ifdef GST_DISABLE_DEPRECATED
1217 gst_element_class_set_details (GstElementClass * klass,
1218 const GstElementDetails * details);
1221 gst_element_class_set_details (GstElementClass * klass,
1222 const GstElementDetails * details)
1224 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1225 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1227 __gst_element_details_copy (&klass->details, details);
1232 * gst_element_class_set_details_simple:
1233 * @klass: class to set details for
1234 * @longname: The long English name of the element. E.g. "File Sink"
1235 * @classification: String describing the type of element, as an unordered list
1236 * separated with slashes ('/'). See draft-klass.txt of the design docs
1237 * for more details and common types. E.g: "Sink/File"
1238 * @description: Sentence describing the purpose of the element.
1239 * E.g: "Write stream to a file"
1240 * @author: Name and contact details of the author(s). Use \n to separate
1241 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1243 * Sets the detailed information for a #GstElementClass. Simpler version of
1244 * gst_element_class_set_details() that generates less linker overhead.
1245 * <note>This function is for use in _base_init functions only.</note>
1247 * The detail parameter strings are copied into the #GstElementDetails for
1248 * the element class.
1253 gst_element_class_set_details_simple (GstElementClass * klass,
1254 const gchar * longname, const gchar * classification,
1255 const gchar * description, const gchar * author)
1257 const GstElementDetails details =
1258 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1259 (gchar *) description, (gchar *) author);
1261 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1263 __gst_element_details_copy (&klass->details, &details);
1267 * gst_element_class_get_pad_template_list:
1268 * @element_class: a #GstElementClass to get pad templates of.
1270 * Retrieves a list of the pad templates associated with @element_class. The
1271 * list must not be modified by the calling code.
1272 * <note>If you use this function in the #GInstanceInitFunc of an object class
1273 * that has subclasses, make sure to pass the g_class parameter of the
1274 * #GInstanceInitFunc here.</note>
1276 * Returns: the #GList of padtemplates.
1279 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1281 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1283 return element_class->padtemplates;
1287 * gst_element_class_get_pad_template:
1288 * @element_class: a #GstElementClass to get the pad template of.
1289 * @name: the name of the #GstPadTemplate to get.
1291 * Retrieves a padtemplate from @element_class with the given name.
1292 * <note>If you use this function in the #GInstanceInitFunc of an object class
1293 * that has subclasses, make sure to pass the g_class parameter of the
1294 * #GInstanceInitFunc here.</note>
1296 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1297 * No unreferencing is necessary.
1300 gst_element_class_get_pad_template (GstElementClass * element_class,
1305 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1306 g_return_val_if_fail (name != NULL, NULL);
1308 padlist = element_class->padtemplates;
1311 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1313 if (strcmp (padtempl->name_template, name) == 0)
1316 padlist = g_list_next (padlist);
1322 static GstPadTemplate *
1323 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1326 GstPadTemplate *tmpl;
1328 tmpl = gst_element_class_get_pad_template (element_class, name);
1329 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1335 /* get a random pad on element of the given direction.
1336 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1339 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1340 GstPadDirection dir)
1342 GstPad *result = NULL;
1345 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1349 GST_OBJECT_LOCK (element);
1350 pads = element->srcpads;
1353 GST_OBJECT_LOCK (element);
1354 pads = element->sinkpads;
1357 goto wrong_direction;
1359 for (; pads; pads = g_list_next (pads)) {
1360 GstPad *pad = GST_PAD_CAST (pads->data);
1362 GST_OBJECT_LOCK (pad);
1363 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1364 GST_DEBUG_PAD_NAME (pad));
1366 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1367 /* if we require a linked pad, and it is not linked, continue the
1369 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1370 GST_DEBUG_PAD_NAME (pad));
1371 GST_OBJECT_UNLOCK (pad);
1374 /* found a pad, stop search */
1375 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1376 GST_DEBUG_PAD_NAME (pad));
1377 GST_OBJECT_UNLOCK (pad);
1383 gst_object_ref (result);
1385 GST_OBJECT_UNLOCK (element);
1389 /* ERROR handling */
1392 g_warning ("unknown pad direction %d", dir);
1398 gst_element_default_send_event (GstElement * element, GstEvent * event)
1400 gboolean result = FALSE;
1403 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1404 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1405 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1408 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1409 "pushing %s event to random %s pad %s:%s",
1410 GST_EVENT_TYPE_NAME (event),
1411 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1412 GST_DEBUG_PAD_NAME (pad));
1414 result = gst_pad_push_event (pad, event);
1415 gst_object_unref (pad);
1417 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1418 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1424 * gst_element_send_event:
1425 * @element: a #GstElement to send the event to.
1426 * @event: the #GstEvent to send to the element.
1428 * Sends an event to an element. If the element doesn't implement an
1429 * event handler, the event will be pushed on a random linked sink pad for
1430 * upstream events or a random linked source pad for downstream events.
1432 * This function takes owership of the provided event so you should
1433 * gst_event_ref() it if you want to reuse the event after this call.
1435 * Returns: %TRUE if the event was handled.
1440 gst_element_send_event (GstElement * element, GstEvent * event)
1442 GstElementClass *oclass;
1443 gboolean result = FALSE;
1445 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1446 g_return_val_if_fail (event != NULL, FALSE);
1448 oclass = GST_ELEMENT_GET_CLASS (element);
1450 GST_STATE_LOCK (element);
1451 if (oclass->send_event) {
1452 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1453 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1454 result = oclass->send_event (element, event);
1456 result = gst_element_default_send_event (element, event);
1458 GST_STATE_UNLOCK (element);
1465 * @element: a #GstElement to send the event to.
1466 * @rate: The new playback rate
1467 * @format: The format of the seek values
1468 * @flags: The optional seek flags.
1469 * @cur_type: The type and flags for the new current position
1470 * @cur: The value of the new current position
1471 * @stop_type: The type and flags for the new stop position
1472 * @stop: The value of the new stop position
1474 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1475 * the parameters. The seek event is sent to the element using
1476 * gst_element_send_event().
1478 * Returns: %TRUE if the event was handled.
1483 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1484 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1485 GstSeekType stop_type, gint64 stop)
1490 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1493 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1494 result = gst_element_send_event (element, event);
1500 * gst_element_get_query_types:
1501 * @element: a #GstElement to query
1503 * Get an array of query types from the element.
1504 * If the element doesn't implement a query types function,
1505 * the query will be forwarded to the peer of a random linked sink pad.
1507 * Returns: An array of #GstQueryType elements that should not
1508 * be freed or modified.
1512 const GstQueryType *
1513 gst_element_get_query_types (GstElement * element)
1515 GstElementClass *oclass;
1516 const GstQueryType *result = NULL;
1518 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1520 oclass = GST_ELEMENT_GET_CLASS (element);
1522 if (oclass->get_query_types) {
1523 result = oclass->get_query_types (element);
1525 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1528 GstPad *peer = gst_pad_get_peer (pad);
1531 result = gst_pad_get_query_types (peer);
1533 gst_object_unref (peer);
1535 gst_object_unref (pad);
1542 gst_element_default_query (GstElement * element, GstQuery * query)
1544 gboolean result = FALSE;
1547 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1549 result = gst_pad_query (pad, query);
1551 gst_object_unref (pad);
1553 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1555 GstPad *peer = gst_pad_get_peer (pad);
1558 result = gst_pad_query (peer, query);
1560 gst_object_unref (peer);
1562 gst_object_unref (pad);
1569 * gst_element_query:
1570 * @element: a #GstElement to perform the query on.
1571 * @query: the #GstQuery.
1573 * Performs a query on the given element.
1575 * For elements that don't implement a query handler, this function
1576 * forwards the query to a random srcpad or to the peer of a
1577 * random linked sinkpad of this element.
1579 * Returns: TRUE if the query could be performed.
1584 gst_element_query (GstElement * element, GstQuery * query)
1586 GstElementClass *oclass;
1587 gboolean result = FALSE;
1589 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1590 g_return_val_if_fail (query != NULL, FALSE);
1592 oclass = GST_ELEMENT_GET_CLASS (element);
1594 if (oclass->query) {
1595 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1596 GST_ELEMENT_NAME (element));
1597 result = oclass->query (element, query);
1599 result = gst_element_default_query (element, query);
1605 * gst_element_post_message:
1606 * @element: a #GstElement posting the message
1607 * @message: a #GstMessage to post
1609 * Post a message on the element's #GstBus. This function takes ownership of the
1610 * message; if you want to access the message after this call, you should add an
1611 * additional reference before calling.
1613 * Returns: %TRUE if the message was successfully posted. The function returns
1614 * %FALSE if the element did not have a bus.
1619 gst_element_post_message (GstElement * element, GstMessage * message)
1622 gboolean result = FALSE;
1624 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1625 g_return_val_if_fail (message != NULL, FALSE);
1627 GST_OBJECT_LOCK (element);
1630 if (G_UNLIKELY (bus == NULL))
1633 gst_object_ref (bus);
1634 GST_OBJECT_UNLOCK (element);
1636 /* we release the element lock when posting the message so that any
1637 * (synchronous) message handlers can operate on the element */
1638 result = gst_bus_post (bus, message);
1639 gst_object_unref (bus);
1646 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1647 "not posting message %p: no bus", message);
1648 GST_OBJECT_UNLOCK (element);
1649 gst_message_unref (message);
1655 * _gst_element_error_printf:
1656 * @format: the printf-like format to use, or %NULL
1658 * This function is only used internally by the gst_element_error() macro.
1660 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1665 _gst_element_error_printf (const gchar * format, ...)
1675 va_start (args, format);
1676 buffer = g_strdup_vprintf (format, args);
1682 * gst_element_message_full:
1683 * @element: a #GstElement to send message from
1684 * @type: the #GstMessageType
1685 * @domain: the GStreamer GError domain this message belongs to
1686 * @code: the GError code belonging to the domain
1687 * @text: an allocated text string to be used as a replacement for the
1688 * default message connected to code, or %NULL
1689 * @debug: an allocated debug message to be used as a replacement for the
1690 * default debugging information, or %NULL
1691 * @file: the source code file where the error was generated
1692 * @function: the source code function where the error was generated
1693 * @line: the source code line where the error was generated
1695 * Post an error, warning or info message on the bus from inside an element.
1697 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1698 * #GST_MESSAGE_INFO.
1702 void gst_element_message_full
1703 (GstElement * element, GstMessageType type,
1704 GQuark domain, gint code, gchar * text,
1705 gchar * debug, const gchar * file, const gchar * function, gint line)
1707 GError *gerror = NULL;
1711 gboolean has_debug = TRUE;
1712 GstMessage *message = NULL;
1715 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1716 g_return_if_fail (GST_IS_ELEMENT (element));
1717 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1718 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1720 /* check if we send the given text or the default error text */
1721 if ((text == NULL) || (text[0] == 0)) {
1722 /* text could have come from g_strdup_printf (""); */
1724 sent_text = gst_error_get_message (domain, code);
1728 /* construct a sent_debug with extra information from source */
1729 if ((debug == NULL) || (debug[0] == 0)) {
1730 /* debug could have come from g_strdup_printf (""); */
1734 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1736 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1737 file, line, function, name, debug);
1739 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1740 file, line, function, name);
1744 /* create gerror and post message */
1745 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1747 gerror = g_error_new_literal (domain, code, sent_text);
1750 case GST_MESSAGE_ERROR:
1752 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1754 case GST_MESSAGE_WARNING:
1755 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1758 case GST_MESSAGE_INFO:
1759 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1763 g_assert_not_reached ();
1766 gst_element_post_message (element, message);
1768 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1769 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1772 g_error_free (gerror);
1773 g_free (sent_debug);
1778 * gst_element_is_locked_state:
1779 * @element: a #GstElement.
1781 * Checks if the state of an element is locked.
1782 * If the state of an element is locked, state changes of the parent don't
1783 * affect the element.
1784 * This way you can leave currently unused elements inside bins. Just lock their
1785 * state before changing the state from #GST_STATE_NULL.
1789 * Returns: TRUE, if the element's state is locked.
1792 gst_element_is_locked_state (GstElement * element)
1796 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1798 GST_OBJECT_LOCK (element);
1799 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1800 GST_OBJECT_UNLOCK (element);
1806 * gst_element_set_locked_state:
1807 * @element: a #GstElement
1808 * @locked_state: TRUE to lock the element's state
1810 * Locks the state of an element, so state changes of the parent don't affect
1811 * this element anymore.
1815 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1816 * or the elements state-locking needed no change.
1819 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1823 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1825 GST_OBJECT_LOCK (element);
1826 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1828 if (G_UNLIKELY (old == locked_state))
1832 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1833 GST_ELEMENT_NAME (element));
1834 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1836 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1837 GST_ELEMENT_NAME (element));
1838 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1840 GST_OBJECT_UNLOCK (element);
1846 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1847 GST_ELEMENT_NAME (element), old);
1848 GST_OBJECT_UNLOCK (element);
1855 * gst_element_sync_state_with_parent:
1856 * @element: a #GstElement.
1858 * Tries to change the state of the element to the same as its parent.
1859 * If this function returns FALSE, the state of element is undefined.
1861 * Returns: TRUE, if the element's state could be synced to the parent's state.
1866 gst_element_sync_state_with_parent (GstElement * element)
1870 GstStateChangeReturn ret;
1872 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1874 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1875 GstState parent_current, parent_pending;
1877 GST_OBJECT_LOCK (parent);
1878 parent_current = GST_STATE (parent);
1879 parent_pending = GST_STATE_PENDING (parent);
1880 GST_OBJECT_UNLOCK (parent);
1882 /* set to pending if there is one, else we set it to the current state of
1884 if (parent_pending != GST_STATE_VOID_PENDING)
1885 target = parent_pending;
1887 target = parent_current;
1889 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1890 "syncing state (%s) to parent %s %s (%s, %s)",
1891 gst_element_state_get_name (GST_STATE (element)),
1892 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1893 gst_element_state_get_name (parent_current),
1894 gst_element_state_get_name (parent_pending));
1896 ret = gst_element_set_state (element, target);
1897 if (ret == GST_STATE_CHANGE_FAILURE)
1900 gst_object_unref (parent);
1904 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1911 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1912 "syncing state failed (%s)",
1913 gst_element_state_change_return_get_name (ret));
1914 gst_object_unref (parent);
1920 static GstStateChangeReturn
1921 gst_element_get_state_func (GstElement * element,
1922 GstState * state, GstState * pending, GstClockTime timeout)
1924 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1925 GstState old_pending;
1927 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1928 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1930 GST_OBJECT_LOCK (element);
1931 ret = GST_STATE_RETURN (element);
1932 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1933 gst_element_state_change_return_get_name (ret));
1935 /* we got an error, report immediately */
1936 if (ret == GST_STATE_CHANGE_FAILURE)
1939 /* we got no_preroll, report immediatly */
1940 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1943 /* no need to wait async if we are not async */
1944 if (ret != GST_STATE_CHANGE_ASYNC)
1947 old_pending = GST_STATE_PENDING (element);
1948 if (old_pending != GST_STATE_VOID_PENDING) {
1949 GTimeVal *timeval, abstimeout;
1952 if (timeout != GST_CLOCK_TIME_NONE) {
1953 glong add = timeout / 1000;
1958 /* make timeout absolute */
1959 g_get_current_time (&abstimeout);
1960 g_time_val_add (&abstimeout, add);
1961 timeval = &abstimeout;
1965 /* get cookie to detect state changes during waiting */
1966 cookie = element->state_cookie;
1968 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1969 "waiting for element to commit state");
1971 /* we have a pending state change, wait for it to complete */
1972 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1973 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1974 /* timeout triggered */
1975 ret = GST_STATE_CHANGE_ASYNC;
1977 if (cookie != element->state_cookie)
1980 /* could be success or failure */
1981 if (old_pending == GST_STATE (element)) {
1982 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1983 ret = GST_STATE_CHANGE_SUCCESS;
1985 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1986 ret = GST_STATE_CHANGE_FAILURE;
1989 /* if nothing is pending anymore we can return SUCCESS */
1990 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1991 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1992 ret = GST_STATE_CHANGE_SUCCESS;
1998 *state = GST_STATE (element);
2000 *pending = GST_STATE_PENDING (element);
2002 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2003 "state current: %s, pending: %s, result: %s",
2004 gst_element_state_get_name (GST_STATE (element)),
2005 gst_element_state_get_name (GST_STATE_PENDING (element)),
2006 gst_element_state_change_return_get_name (ret));
2007 GST_OBJECT_UNLOCK (element);
2014 *state = GST_STATE_VOID_PENDING;
2016 *pending = GST_STATE_VOID_PENDING;
2018 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2020 GST_OBJECT_UNLOCK (element);
2022 return GST_STATE_CHANGE_FAILURE;
2027 * gst_element_get_state:
2028 * @element: a #GstElement to get the state of.
2029 * @state: (out): a pointer to #GstState to hold the state. Can be %NULL.
2030 * @pending: (out): a pointer to #GstState to hold the pending state.
2032 * @timeout: a #GstClockTime to specify the timeout for an async
2033 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2035 * Gets the state of the element.
2037 * For elements that performed an ASYNC state change, as reported by
2038 * gst_element_set_state(), this function will block up to the
2039 * specified timeout value for the state change to complete.
2040 * If the element completes the state change or goes into
2041 * an error, this function returns immediately with a return value of
2042 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2044 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2045 * returns the current and pending state immediately.
2047 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2048 * successfully changed its state but is not able to provide data yet.
2049 * This mostly happens for live sources that only produce data in
2050 * %GST_STATE_PLAYING. While the state change return is equivalent to
2051 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2052 * some sink elements might not be able to complete their state change because
2053 * an element is not producing data to complete the preroll. When setting the
2054 * element to playing, the preroll will complete and playback will start.
2056 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2057 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2058 * element is still performing a state change or
2059 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2063 GstStateChangeReturn
2064 gst_element_get_state (GstElement * element,
2065 GstState * state, GstState * pending, GstClockTime timeout)
2067 GstElementClass *oclass;
2068 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2070 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2072 oclass = GST_ELEMENT_GET_CLASS (element);
2074 if (oclass->get_state)
2075 result = (oclass->get_state) (element, state, pending, timeout);
2081 * gst_element_abort_state:
2082 * @element: a #GstElement to abort the state of.
2084 * Abort the state change of the element. This function is used
2085 * by elements that do asynchronous state changes and find out
2086 * something is wrong.
2088 * This function should be called with the STATE_LOCK held.
2093 gst_element_abort_state (GstElement * element)
2097 #ifndef GST_DISABLE_GST_DEBUG
2101 g_return_if_fail (GST_IS_ELEMENT (element));
2103 GST_OBJECT_LOCK (element);
2104 pending = GST_STATE_PENDING (element);
2106 if (pending == GST_STATE_VOID_PENDING ||
2107 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2108 goto nothing_aborted;
2110 #ifndef GST_DISABLE_GST_DEBUG
2111 old_state = GST_STATE (element);
2113 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2114 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2115 gst_element_state_get_name (pending));
2119 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2121 GST_STATE_BROADCAST (element);
2122 GST_OBJECT_UNLOCK (element);
2128 GST_OBJECT_UNLOCK (element);
2134 * gst_element_continue_state:
2135 * @element: a #GstElement to continue the state change of.
2136 * @ret: The previous state return value
2138 * Commit the state change of the element and proceed to the next
2139 * pending state if any. This function is used
2140 * by elements that do asynchronous state changes.
2141 * The core will normally call this method automatically when an
2142 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2144 * If after calling this method the element still has not reached
2145 * the pending state, the next state change is performed.
2147 * This method is used internally and should normally not be called by plugins
2150 * Returns: The result of the commit state change.
2154 GstStateChangeReturn
2155 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2157 GstStateChangeReturn old_ret;
2158 GstState old_state, old_next;
2159 GstState current, next, pending;
2160 GstMessage *message;
2161 GstStateChange transition;
2163 GST_OBJECT_LOCK (element);
2164 old_ret = GST_STATE_RETURN (element);
2165 GST_STATE_RETURN (element) = ret;
2166 pending = GST_STATE_PENDING (element);
2168 /* check if there is something to commit */
2169 if (pending == GST_STATE_VOID_PENDING)
2170 goto nothing_pending;
2172 old_state = GST_STATE (element);
2173 /* this is the state we should go to next */
2174 old_next = GST_STATE_NEXT (element);
2175 /* update current state */
2176 current = GST_STATE (element) = old_next;
2178 /* see if we reached the final state */
2179 if (pending == current)
2182 next = GST_STATE_GET_NEXT (current, pending);
2183 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2185 GST_STATE_NEXT (element) = next;
2187 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2188 GST_OBJECT_UNLOCK (element);
2190 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2191 "committing state from %s to %s, pending %s, next %s",
2192 gst_element_state_get_name (old_state),
2193 gst_element_state_get_name (old_next),
2194 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2196 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2197 old_state, old_next, pending);
2198 gst_element_post_message (element, message);
2200 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2201 "continue state change %s to %s, final %s",
2202 gst_element_state_get_name (current),
2203 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2205 ret = gst_element_change_state (element, transition);
2211 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2212 GST_OBJECT_UNLOCK (element);
2217 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2218 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2220 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2221 "completed state change to %s", gst_element_state_get_name (pending));
2222 GST_OBJECT_UNLOCK (element);
2224 /* don't post silly messages with the same state. This can happen
2225 * when an element state is changed to what it already was. For bins
2226 * this can be the result of a lost state, which we check with the
2227 * previous return value.
2228 * We do signal the cond though as a _get_state() might be blocking
2230 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2231 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2232 "posting state-changed %s to %s",
2233 gst_element_state_get_name (old_state),
2234 gst_element_state_get_name (old_next));
2236 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2237 old_next, GST_STATE_VOID_PENDING);
2238 gst_element_post_message (element, message);
2241 GST_STATE_BROADCAST (element);
2248 * gst_element_lost_state_full:
2249 * @element: a #GstElement the state is lost of
2250 * @new_base_time: if a new base time should be distributed
2252 * Brings the element to the lost state. The current state of the
2253 * element is copied to the pending state so that any call to
2254 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2256 * An ASYNC_START message is posted with indication to distribute a new
2257 * base_time to the element when @new_base_time is %TRUE.
2258 * If the element was PLAYING, it will go to PAUSED. The element
2259 * will be restored to its PLAYING state by the parent pipeline when it
2262 * This is mostly used for elements that lost their preroll buffer
2263 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2264 * they will go to their pending state again when a new preroll buffer is
2265 * queued. This function can only be called when the element is currently
2266 * not in error or an async state change.
2268 * This function is used internally and should normally not be called from
2269 * plugins or applications.
2276 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2278 GstState old_state, new_state;
2279 GstMessage *message;
2281 g_return_if_fail (GST_IS_ELEMENT (element));
2283 GST_OBJECT_LOCK (element);
2284 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2287 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2288 goto only_async_start;
2290 old_state = GST_STATE (element);
2292 /* when we were PLAYING, the new state is PAUSED. We will also not
2293 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2294 * when we preroll. */
2295 if (old_state > GST_STATE_PAUSED)
2296 new_state = GST_STATE_PAUSED;
2298 new_state = old_state;
2300 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2301 "lost state of %s to %s", gst_element_state_get_name (old_state),
2302 gst_element_state_get_name (new_state));
2304 GST_STATE (element) = new_state;
2305 GST_STATE_NEXT (element) = new_state;
2306 GST_STATE_PENDING (element) = new_state;
2307 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2309 GST_ELEMENT_START_TIME (element) = 0;
2310 GST_OBJECT_UNLOCK (element);
2312 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2313 new_state, new_state, new_state);
2314 gst_element_post_message (element, message);
2317 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2318 gst_element_post_message (element, message);
2324 GST_OBJECT_UNLOCK (element);
2329 GST_OBJECT_UNLOCK (element);
2331 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2332 gst_element_post_message (element, message);
2338 * gst_element_lost_state:
2339 * @element: a #GstElement the state is lost of
2341 * Brings the element to the lost state. This function calls
2342 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2344 * This function is used internally and should normally not be called from
2345 * plugins or applications.
2350 gst_element_lost_state (GstElement * element)
2352 gst_element_lost_state_full (element, TRUE);
2356 * gst_element_set_state:
2357 * @element: a #GstElement to change state of.
2358 * @state: the element's new #GstState.
2360 * Sets the state of the element. This function will try to set the
2361 * requested state by going through all the intermediary states and calling
2362 * the class's state change function for each.
2364 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2365 * element will perform the remainder of the state change asynchronously in
2367 * An application can use gst_element_get_state() to wait for the completion
2368 * of the state change or it can wait for a state change message on the bus.
2370 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2371 * #GST_STATE_CHANGE_ASYNC.
2373 * Returns: Result of the state change using #GstStateChangeReturn.
2377 GstStateChangeReturn
2378 gst_element_set_state (GstElement * element, GstState state)
2380 GstElementClass *oclass;
2381 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2383 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2385 oclass = GST_ELEMENT_GET_CLASS (element);
2387 if (oclass->set_state)
2388 result = (oclass->set_state) (element, state);
2394 * default set state function, calculates the next state based
2395 * on current state and calls the change_state function
2397 static GstStateChangeReturn
2398 gst_element_set_state_func (GstElement * element, GstState state)
2400 GstState current, next, old_pending;
2401 GstStateChangeReturn ret;
2402 GstStateChange transition;
2403 GstStateChangeReturn old_ret;
2405 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2407 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2408 gst_element_state_get_name (state));
2410 /* state lock is taken to protect the set_state() and get_state()
2411 * procedures, it does not lock any variables. */
2412 GST_STATE_LOCK (element);
2414 /* now calculate how to get to the new state */
2415 GST_OBJECT_LOCK (element);
2416 old_ret = GST_STATE_RETURN (element);
2417 /* previous state change returned an error, remove all pending
2418 * and next states */
2419 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2420 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2421 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2422 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2425 current = GST_STATE (element);
2426 next = GST_STATE_NEXT (element);
2427 old_pending = GST_STATE_PENDING (element);
2429 /* this is the (new) state we should go to. TARGET is the last state we set on
2431 if (state != GST_STATE_TARGET (element)) {
2432 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2433 "setting target state to %s", gst_element_state_get_name (state));
2434 GST_STATE_TARGET (element) = state;
2435 /* increment state cookie so that we can track each state change. We only do
2436 * this if this is actually a new state change. */
2437 element->state_cookie++;
2439 GST_STATE_PENDING (element) = state;
2441 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2442 "current %s, old_pending %s, next %s, old return %s",
2443 gst_element_state_get_name (current),
2444 gst_element_state_get_name (old_pending),
2445 gst_element_state_get_name (next),
2446 gst_element_state_change_return_get_name (old_ret));
2448 /* if the element was busy doing a state change, we just update the
2449 * target state, it'll get to it async then. */
2450 if (old_pending != GST_STATE_VOID_PENDING) {
2451 /* upwards state change will happen ASYNC */
2452 if (old_pending <= state)
2454 /* element is going to this state already */
2455 else if (next == state)
2457 /* element was performing an ASYNC upward state change and
2458 * we request to go downward again. Start from the next pending
2460 else if (next > state
2461 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2465 next = GST_STATE_GET_NEXT (current, state);
2466 /* now we store the next state */
2467 GST_STATE_NEXT (element) = next;
2468 /* mark busy, we need to check that there is actually a state change
2469 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2470 * the default element change_state function has no way to know what the
2471 * old value was... could consider this a FIXME...*/
2472 if (current != next)
2473 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2475 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2477 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2478 "%s: setting state from %s to %s",
2479 (next != state ? "intermediate" : "final"),
2480 gst_element_state_get_name (current), gst_element_state_get_name (next));
2482 /* now signal any waiters, they will error since the cookie was incremented */
2483 GST_STATE_BROADCAST (element);
2485 GST_OBJECT_UNLOCK (element);
2487 ret = gst_element_change_state (element, transition);
2489 GST_STATE_UNLOCK (element);
2491 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2492 gst_element_state_change_return_get_name (ret));
2498 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2499 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2500 "element was busy with async state change");
2501 GST_OBJECT_UNLOCK (element);
2503 GST_STATE_UNLOCK (element);
2505 return GST_STATE_CHANGE_ASYNC;
2510 * gst_element_change_state:
2511 * @element: a #GstElement
2512 * @transition: the requested transition
2514 * Perform @transition on @element.
2516 * This function must be called with STATE_LOCK held and is mainly used
2519 * Returns: the #GstStateChangeReturn of the state transition.
2521 GstStateChangeReturn
2522 gst_element_change_state (GstElement * element, GstStateChange transition)
2524 GstElementClass *oclass;
2525 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2527 oclass = GST_ELEMENT_GET_CLASS (element);
2529 /* call the state change function so it can set the state */
2530 if (oclass->change_state)
2531 ret = (oclass->change_state) (element, transition);
2533 ret = GST_STATE_CHANGE_FAILURE;
2536 case GST_STATE_CHANGE_FAILURE:
2537 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2538 "have FAILURE change_state return");
2539 /* state change failure */
2540 gst_element_abort_state (element);
2542 case GST_STATE_CHANGE_ASYNC:
2546 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2547 "element will change state ASYNC");
2549 target = GST_STATE_TARGET (element);
2551 if (target > GST_STATE_READY)
2554 /* else we just continue the state change downwards */
2555 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2556 "forcing commit state %s <= %s",
2557 gst_element_state_get_name (target),
2558 gst_element_state_get_name (GST_STATE_READY));
2560 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2563 case GST_STATE_CHANGE_SUCCESS:
2564 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2565 "element changed state SUCCESS");
2566 /* we can commit the state now which will proceeed to
2568 ret = gst_element_continue_state (element, ret);
2570 case GST_STATE_CHANGE_NO_PREROLL:
2571 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2572 "element changed state NO_PREROLL");
2573 /* we can commit the state now which will proceeed to
2575 ret = gst_element_continue_state (element, ret);
2578 goto invalid_return;
2581 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2586 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2594 GST_OBJECT_LOCK (element);
2595 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2596 g_critical ("%s: unknown return value %d from a state change function",
2597 GST_ELEMENT_NAME (element), ret);
2599 /* we are in error now */
2600 ret = GST_STATE_CHANGE_FAILURE;
2601 GST_STATE_RETURN (element) = ret;
2602 GST_OBJECT_UNLOCK (element);
2608 /* gst_iterator_fold functions for pads_activate
2609 * Note how we don't stop the iterator when we fail an activation. This is
2610 * probably a FIXME since when one pad activation fails, we don't want to
2611 * continue our state change. */
2613 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2615 if (!gst_pad_set_active (pad, *active))
2616 g_value_set_boolean (ret, FALSE);
2618 /* unref the object that was reffed for us by _fold */
2619 gst_object_unref (pad);
2623 /* set the caps on the pad to NULL */
2625 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2627 gst_pad_set_caps (pad, NULL);
2628 gst_object_unref (pad);
2632 /* returns false on error or early cutout (will never happen because the fold
2633 * function always returns TRUE, see FIXME above) of the fold, true if all
2634 * pads in @iter were (de)activated successfully. */
2636 iterator_activate_fold_with_resync (GstIterator * iter,
2637 GstIteratorFoldFunction func, gpointer user_data)
2639 GstIteratorResult ires;
2642 /* no need to unset this later, it's just a boolean */
2643 g_value_init (&ret, G_TYPE_BOOLEAN);
2644 g_value_set_boolean (&ret, TRUE);
2647 ires = gst_iterator_fold (iter, func, &ret, user_data);
2649 case GST_ITERATOR_RESYNC:
2650 /* need to reset the result again */
2651 g_value_set_boolean (&ret, TRUE);
2652 gst_iterator_resync (iter);
2654 case GST_ITERATOR_DONE:
2655 /* all pads iterated, return collected value */
2658 /* iterator returned _ERROR or premature end with _OK,
2659 * mark an error and exit */
2660 g_value_set_boolean (&ret, FALSE);
2665 /* return collected value */
2666 return g_value_get_boolean (&ret);
2669 /* is called with STATE_LOCK
2671 * Pads are activated from source pads to sinkpads.
2674 gst_element_pads_activate (GstElement * element, gboolean active)
2679 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2680 "pads_activate with active %d", active);
2682 iter = gst_element_iterate_src_pads (element);
2684 iterator_activate_fold_with_resync (iter,
2685 (GstIteratorFoldFunction) activate_pads, &active);
2686 gst_iterator_free (iter);
2687 if (G_UNLIKELY (!res))
2690 iter = gst_element_iterate_sink_pads (element);
2692 iterator_activate_fold_with_resync (iter,
2693 (GstIteratorFoldFunction) activate_pads, &active);
2694 gst_iterator_free (iter);
2695 if (G_UNLIKELY (!res))
2699 /* clear the caps on all pads, this should never fail */
2700 iter = gst_element_iterate_pads (element);
2702 iterator_activate_fold_with_resync (iter,
2703 (GstIteratorFoldFunction) clear_caps, &active);
2704 gst_iterator_free (iter);
2705 if (G_UNLIKELY (!res))
2709 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2710 "pads_activate successful");
2717 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2718 "source pads_activate failed");
2723 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2724 "sink pads_activate failed");
2729 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2730 "failed to clear caps on pads");
2735 /* is called with STATE_LOCK */
2736 static GstStateChangeReturn
2737 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2739 GstState state, next;
2740 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2743 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2745 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2746 next = GST_STATE_TRANSITION_NEXT (transition);
2748 /* if the element already is in the given state, we just return success */
2749 if (next == GST_STATE_VOID_PENDING || state == next)
2752 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2753 "default handler tries setting state from %s to %s (%04x)",
2754 gst_element_state_get_name (state),
2755 gst_element_state_get_name (next), transition);
2757 switch (transition) {
2758 case GST_STATE_CHANGE_NULL_TO_READY:
2760 case GST_STATE_CHANGE_READY_TO_PAUSED:
2761 if (!gst_element_pads_activate (element, TRUE)) {
2762 result = GST_STATE_CHANGE_FAILURE;
2765 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2767 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2769 case GST_STATE_CHANGE_PAUSED_TO_READY:
2770 case GST_STATE_CHANGE_READY_TO_NULL:
2771 /* deactivate pads in both cases, since they are activated on
2772 ready->paused but the element might not have made it to paused */
2773 if (!gst_element_pads_activate (element, FALSE)) {
2774 result = GST_STATE_CHANGE_FAILURE;
2776 gst_element_set_base_time (element, 0);
2779 /* In null state release the reference to the clock */
2780 GST_OBJECT_LOCK (element);
2781 clock_p = &element->clock;
2782 gst_object_replace ((GstObject **) clock_p, NULL);
2783 GST_OBJECT_UNLOCK (element);
2786 /* this will catch real but unhandled state changes;
2787 * can only be caused by:
2788 * - a new state was added
2789 * - somehow the element was asked to jump across an intermediate state
2791 g_warning ("Unhandled state change from %s to %s",
2792 gst_element_state_get_name (state),
2793 gst_element_state_get_name (next));
2800 GST_OBJECT_LOCK (element);
2801 result = GST_STATE_RETURN (element);
2802 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2803 "element is already in the %s state",
2804 gst_element_state_get_name (state));
2805 GST_OBJECT_UNLOCK (element);
2812 * gst_element_get_factory:
2813 * @element: a #GstElement to request the element factory of.
2815 * Retrieves the factory that was used to create this element.
2817 * Returns: the #GstElementFactory used for creating this element.
2818 * no refcounting is needed.
2821 gst_element_get_factory (GstElement * element)
2823 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2825 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2829 gst_element_dispose (GObject * object)
2831 GstElement *element = GST_ELEMENT_CAST (object);
2835 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2837 if (GST_STATE (element) != GST_STATE_NULL)
2840 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2841 "removing %d pads", g_list_length (element->pads));
2842 /* first we break all our links with the outside */
2843 while (element->pads && element->pads->data) {
2844 /* don't call _remove_pad with NULL */
2845 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2847 if (G_UNLIKELY (element->pads != NULL)) {
2848 g_critical ("could not remove pads from element %s",
2849 GST_STR_NULL (GST_OBJECT_NAME (object)));
2852 GST_OBJECT_LOCK (element);
2853 clock_p = &element->clock;
2854 bus_p = &element->bus;
2855 gst_object_replace ((GstObject **) clock_p, NULL);
2856 gst_object_replace ((GstObject **) bus_p, NULL);
2857 GST_OBJECT_UNLOCK (element);
2859 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2861 G_OBJECT_CLASS (parent_class)->dispose (object);
2870 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2872 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2874 "You need to explicitly set elements to the NULL state before\n"
2875 "dropping the final reference, to allow them to clean up.\n"
2876 "This problem may also be caused by a refcounting bug in the\n"
2877 "application or some element.\n",
2878 GST_OBJECT_NAME (element),
2879 gst_element_state_get_name (GST_STATE (element)),
2880 is_locked ? " (locked)" : "");
2886 gst_element_finalize (GObject * object)
2888 GstElement *element = GST_ELEMENT_CAST (object);
2890 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2892 GST_STATE_LOCK (element);
2893 if (element->state_cond)
2894 g_cond_free (element->state_cond);
2895 element->state_cond = NULL;
2896 GST_STATE_UNLOCK (element);
2897 g_static_rec_mutex_free (element->state_lock);
2898 g_slice_free (GStaticRecMutex, element->state_lock);
2899 element->state_lock = NULL;
2901 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2903 G_OBJECT_CLASS (parent_class)->finalize (object);
2906 #ifndef GST_DISABLE_LOADSAVE
2908 * gst_element_save_thyself:
2909 * @element: a #GstElement to save.
2910 * @parent: the xml parent node.
2912 * Saves the element as part of the given XML structure.
2914 * Returns: the new #xmlNodePtr.
2917 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2920 GstElementClass *oclass;
2921 GParamSpec **specs, *spec;
2924 GValue value = { 0, };
2925 GstElement *element;
2927 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2929 element = GST_ELEMENT_CAST (object);
2931 oclass = GST_ELEMENT_GET_CLASS (element);
2933 xmlNewChild (parent, NULL, (xmlChar *) "name",
2934 (xmlChar *) GST_ELEMENT_NAME (element));
2936 if (oclass->elementfactory != NULL) {
2937 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2939 xmlNewChild (parent, NULL, (xmlChar *) "type",
2940 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2944 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2946 for (i = 0; i < nspecs; i++) {
2948 if (spec->flags & G_PARAM_READABLE) {
2952 g_value_init (&value, spec->value_type);
2954 g_object_get_property (G_OBJECT (element), spec->name, &value);
2955 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2956 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2958 if (G_IS_PARAM_SPEC_STRING (spec))
2959 contents = g_value_dup_string (&value);
2960 else if (G_IS_PARAM_SPEC_ENUM (spec))
2961 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2962 else if (G_IS_PARAM_SPEC_INT64 (spec))
2963 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2964 g_value_get_int64 (&value));
2965 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
2966 if (g_value_get_boxed (&value) != NULL) {
2967 contents = g_strdup_value_contents (&value);
2969 contents = g_strdup ("NULL");
2972 contents = g_strdup_value_contents (&value);
2974 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2977 g_value_unset (&value);
2983 pads = g_list_last (GST_ELEMENT_PADS (element));
2986 GstPad *pad = GST_PAD_CAST (pads->data);
2988 /* figure out if it's a direct pad or a ghostpad */
2989 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
2990 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
2992 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
2994 pads = g_list_previous (pads);
3001 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3003 xmlNodePtr children;
3004 GstElement *element;
3006 gchar *value = NULL;
3008 element = GST_ELEMENT_CAST (object);
3009 g_return_if_fail (element != NULL);
3012 children = self->xmlChildrenNode;
3014 if (!strcmp ((char *) children->name, "param")) {
3015 xmlNodePtr child = children->xmlChildrenNode;
3018 if (!strcmp ((char *) child->name, "name")) {
3019 name = (gchar *) xmlNodeGetContent (child);
3020 } else if (!strcmp ((char *) child->name, "value")) {
3021 value = (gchar *) xmlNodeGetContent (child);
3023 child = child->next;
3025 /* FIXME: can this just be g_object_set ? */
3026 gst_util_set_object_arg (G_OBJECT (element), name, value);
3027 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3031 children = children->next;
3035 children = self->xmlChildrenNode;
3037 if (!strcmp ((char *) children->name, "pad")) {
3038 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3040 children = children->next;
3043 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3044 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3046 #endif /* GST_DISABLE_LOADSAVE */
3049 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3053 g_return_if_fail (GST_IS_ELEMENT (element));
3055 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3057 GST_OBJECT_LOCK (element);
3058 bus_p = &GST_ELEMENT_BUS (element);
3059 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3060 GST_OBJECT_UNLOCK (element);
3064 * gst_element_set_bus:
3065 * @element: a #GstElement to set the bus of.
3066 * @bus: the #GstBus to set.
3068 * Sets the bus of the element. Increases the refcount on the bus.
3069 * For internal use only, unless you're testing elements.
3074 gst_element_set_bus (GstElement * element, GstBus * bus)
3076 GstElementClass *oclass;
3078 g_return_if_fail (GST_IS_ELEMENT (element));
3080 oclass = GST_ELEMENT_GET_CLASS (element);
3082 if (oclass->set_bus)
3083 oclass->set_bus (element, bus);
3087 * gst_element_get_bus:
3088 * @element: a #GstElement to get the bus of.
3090 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3091 * bus for the application.
3093 * Returns: the element's #GstBus. unref after usage.
3098 gst_element_get_bus (GstElement * element)
3100 GstBus *result = NULL;
3102 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3104 GST_OBJECT_LOCK (element);
3105 if ((result = GST_ELEMENT_BUS (element)))
3106 gst_object_ref (result);
3107 GST_OBJECT_UNLOCK (element);
3109 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,