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') {
1031 tmp = strtol (data, &endptr, 10);
1032 if (endptr && *endptr == '\0') {
1052 pad = gst_element_request_pad (element, templ, req_name);
1058 * gst_element_get_pad:
1059 * @element: a #GstElement.
1060 * @name: the name of the pad to retrieve.
1062 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1063 * first, then gst_element_get_request_pad().
1065 * Deprecated: This function is deprecated as it's unclear if the reference
1066 * to the result pad should be released with gst_object_unref() in case of a static pad
1067 * or gst_element_release_request_pad() in case of a request pad.
1068 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1070 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1071 * depending on the type of the pad.
1073 #ifndef GST_REMOVE_DEPRECATED
1074 #ifdef GST_DISABLE_DEPRECATED
1075 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1078 gst_element_get_pad (GstElement * element, const gchar * name)
1082 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1083 g_return_val_if_fail (name != NULL, NULL);
1085 pad = gst_element_get_static_pad (element, name);
1087 pad = gst_element_get_request_pad (element, name);
1091 #endif /* GST_REMOVE_DEPRECATED */
1093 static GstIteratorItem
1094 iterate_pad (GstIterator * it, GstPad * pad)
1096 gst_object_ref (pad);
1097 return GST_ITERATOR_ITEM_PASS;
1100 static GstIterator *
1101 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1103 GstIterator *result;
1105 GST_OBJECT_LOCK (element);
1106 gst_object_ref (element);
1107 result = gst_iterator_new_list (GST_TYPE_PAD,
1108 GST_OBJECT_GET_LOCK (element),
1109 &element->pads_cookie,
1112 (GstIteratorItemFunction) iterate_pad,
1113 (GstIteratorDisposeFunction) gst_object_unref);
1114 GST_OBJECT_UNLOCK (element);
1120 * gst_element_iterate_pads:
1121 * @element: a #GstElement to iterate pads of.
1123 * Retrieves an iterattor of @element's pads. The iterator should
1124 * be freed after usage.
1126 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1131 gst_element_iterate_pads (GstElement * element)
1133 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1135 return gst_element_iterate_pad_list (element, &element->pads);
1139 * gst_element_iterate_src_pads:
1140 * @element: a #GstElement.
1142 * Retrieves an iterator of @element's source pads.
1144 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1149 gst_element_iterate_src_pads (GstElement * element)
1151 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1153 return gst_element_iterate_pad_list (element, &element->srcpads);
1157 * gst_element_iterate_sink_pads:
1158 * @element: a #GstElement.
1160 * Retrieves an iterator of @element's sink pads.
1162 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1167 gst_element_iterate_sink_pads (GstElement * element)
1169 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1171 return gst_element_iterate_pad_list (element, &element->sinkpads);
1175 * gst_element_class_add_pad_template:
1176 * @klass: the #GstElementClass to add the pad template to.
1177 * @templ: a #GstPadTemplate to add to the element class.
1179 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1180 * functions of classes.
1183 gst_element_class_add_pad_template (GstElementClass * klass,
1184 GstPadTemplate * templ)
1186 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1187 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1189 /* FIXME 0.11: allow replacing the pad templates by
1190 * calling this with the same name as an already existing pad
1191 * template. For this we _must_ _not_ ref the added pad template
1192 * a second time and _must_ document that this function takes
1193 * ownership of the pad template. Otherwise we will leak pad templates
1194 * or the caller unref's the pad template and it disappears */
1195 /* avoid registering pad templates with the same name */
1196 g_return_if_fail (gst_element_class_get_pad_template (klass,
1197 templ->name_template) == NULL);
1199 klass->padtemplates = g_list_append (klass->padtemplates,
1200 gst_object_ref (templ));
1201 klass->numpadtemplates++;
1205 * gst_element_class_set_details:
1206 * @klass: class to set details for
1207 * @details: details to set
1209 * Sets the detailed information for a #GstElementClass.
1210 * <note>This function is for use in _base_init functions only.</note>
1212 * The @details are copied.
1214 * Deprecated: Use gst_element_class_set_details_simple() instead.
1216 #ifndef GST_REMOVE_DEPRECATED
1217 #ifdef GST_DISABLE_DEPRECATED
1219 gst_element_class_set_details (GstElementClass * klass,
1220 const GstElementDetails * details);
1223 gst_element_class_set_details (GstElementClass * klass,
1224 const GstElementDetails * details)
1226 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1227 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1229 __gst_element_details_copy (&klass->details, details);
1234 * gst_element_class_set_details_simple:
1235 * @klass: class to set details for
1236 * @longname: The long English name of the element. E.g. "File Sink"
1237 * @classification: String describing the type of element, as an unordered list
1238 * separated with slashes ('/'). See draft-klass.txt of the design docs
1239 * for more details and common types. E.g: "Sink/File"
1240 * @description: Sentence describing the purpose of the element.
1241 * E.g: "Write stream to a file"
1242 * @author: Name and contact details of the author(s). Use \n to separate
1243 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1245 * Sets the detailed information for a #GstElementClass. Simpler version of
1246 * gst_element_class_set_details() that generates less linker overhead.
1247 * <note>This function is for use in _base_init functions only.</note>
1249 * The detail parameter strings are copied into the #GstElementDetails for
1250 * the element class.
1255 gst_element_class_set_details_simple (GstElementClass * klass,
1256 const gchar * longname, const gchar * classification,
1257 const gchar * description, const gchar * author)
1259 const GstElementDetails details =
1260 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1261 (gchar *) description, (gchar *) author);
1263 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1265 __gst_element_details_copy (&klass->details, &details);
1269 * gst_element_class_get_pad_template_list:
1270 * @element_class: a #GstElementClass to get pad templates of.
1272 * Retrieves a list of the pad templates associated with @element_class. The
1273 * list must not be modified by the calling code.
1274 * <note>If you use this function in the #GInstanceInitFunc of an object class
1275 * that has subclasses, make sure to pass the g_class parameter of the
1276 * #GInstanceInitFunc here.</note>
1278 * Returns: the #GList of padtemplates.
1281 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1283 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1285 return element_class->padtemplates;
1289 * gst_element_class_get_pad_template:
1290 * @element_class: a #GstElementClass to get the pad template of.
1291 * @name: the name of the #GstPadTemplate to get.
1293 * Retrieves a padtemplate from @element_class with the given name.
1294 * <note>If you use this function in the #GInstanceInitFunc of an object class
1295 * that has subclasses, make sure to pass the g_class parameter of the
1296 * #GInstanceInitFunc here.</note>
1298 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1299 * No unreferencing is necessary.
1302 gst_element_class_get_pad_template (GstElementClass * element_class,
1307 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1308 g_return_val_if_fail (name != NULL, NULL);
1310 padlist = element_class->padtemplates;
1313 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1315 if (strcmp (padtempl->name_template, name) == 0)
1318 padlist = g_list_next (padlist);
1324 static GstPadTemplate *
1325 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1328 GstPadTemplate *tmpl;
1330 tmpl = gst_element_class_get_pad_template (element_class, name);
1331 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1337 /* get a random pad on element of the given direction.
1338 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1341 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1342 GstPadDirection dir)
1344 GstPad *result = NULL;
1347 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1351 GST_OBJECT_LOCK (element);
1352 pads = element->srcpads;
1355 GST_OBJECT_LOCK (element);
1356 pads = element->sinkpads;
1359 goto wrong_direction;
1361 for (; pads; pads = g_list_next (pads)) {
1362 GstPad *pad = GST_PAD_CAST (pads->data);
1364 GST_OBJECT_LOCK (pad);
1365 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1366 GST_DEBUG_PAD_NAME (pad));
1368 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1369 /* if we require a linked pad, and it is not linked, continue the
1371 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1372 GST_DEBUG_PAD_NAME (pad));
1373 GST_OBJECT_UNLOCK (pad);
1376 /* found a pad, stop search */
1377 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1378 GST_DEBUG_PAD_NAME (pad));
1379 GST_OBJECT_UNLOCK (pad);
1385 gst_object_ref (result);
1387 GST_OBJECT_UNLOCK (element);
1391 /* ERROR handling */
1394 g_warning ("unknown pad direction %d", dir);
1400 gst_element_default_send_event (GstElement * element, GstEvent * event)
1402 gboolean result = FALSE;
1405 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1406 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1407 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1410 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1411 "pushing %s event to random %s pad %s:%s",
1412 GST_EVENT_TYPE_NAME (event),
1413 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1414 GST_DEBUG_PAD_NAME (pad));
1416 result = gst_pad_push_event (pad, event);
1417 gst_object_unref (pad);
1419 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1420 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1426 * gst_element_send_event:
1427 * @element: a #GstElement to send the event to.
1428 * @event: the #GstEvent to send to the element.
1430 * Sends an event to an element. If the element doesn't implement an
1431 * event handler, the event will be pushed on a random linked sink pad for
1432 * upstream events or a random linked source pad for downstream events.
1434 * This function takes owership of the provided event so you should
1435 * gst_event_ref() it if you want to reuse the event after this call.
1437 * Returns: %TRUE if the event was handled.
1442 gst_element_send_event (GstElement * element, GstEvent * event)
1444 GstElementClass *oclass;
1445 gboolean result = FALSE;
1447 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1448 g_return_val_if_fail (event != NULL, FALSE);
1450 oclass = GST_ELEMENT_GET_CLASS (element);
1452 GST_STATE_LOCK (element);
1453 if (oclass->send_event) {
1454 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1455 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1456 result = oclass->send_event (element, event);
1458 result = gst_element_default_send_event (element, event);
1460 GST_STATE_UNLOCK (element);
1467 * @element: a #GstElement to send the event to.
1468 * @rate: The new playback rate
1469 * @format: The format of the seek values
1470 * @flags: The optional seek flags.
1471 * @cur_type: The type and flags for the new current position
1472 * @cur: The value of the new current position
1473 * @stop_type: The type and flags for the new stop position
1474 * @stop: The value of the new stop position
1476 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1477 * the parameters. The seek event is sent to the element using
1478 * gst_element_send_event().
1480 * Returns: %TRUE if the event was handled.
1485 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1486 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1487 GstSeekType stop_type, gint64 stop)
1492 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1495 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1496 result = gst_element_send_event (element, event);
1502 * gst_element_get_query_types:
1503 * @element: a #GstElement to query
1505 * Get an array of query types from the element.
1506 * If the element doesn't implement a query types function,
1507 * the query will be forwarded to the peer of a random linked sink pad.
1509 * Returns: An array of #GstQueryType elements that should not
1510 * be freed or modified.
1514 const GstQueryType *
1515 gst_element_get_query_types (GstElement * element)
1517 GstElementClass *oclass;
1518 const GstQueryType *result = NULL;
1520 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1522 oclass = GST_ELEMENT_GET_CLASS (element);
1524 if (oclass->get_query_types) {
1525 result = oclass->get_query_types (element);
1527 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1530 GstPad *peer = gst_pad_get_peer (pad);
1533 result = gst_pad_get_query_types (peer);
1535 gst_object_unref (peer);
1537 gst_object_unref (pad);
1544 gst_element_default_query (GstElement * element, GstQuery * query)
1546 gboolean result = FALSE;
1549 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1551 result = gst_pad_query (pad, query);
1553 gst_object_unref (pad);
1555 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1557 GstPad *peer = gst_pad_get_peer (pad);
1560 result = gst_pad_query (peer, query);
1562 gst_object_unref (peer);
1564 gst_object_unref (pad);
1571 * gst_element_query:
1572 * @element: a #GstElement to perform the query on.
1573 * @query: the #GstQuery.
1575 * Performs a query on the given element.
1577 * For elements that don't implement a query handler, this function
1578 * forwards the query to a random srcpad or to the peer of a
1579 * random linked sinkpad of this element.
1581 * Returns: TRUE if the query could be performed.
1586 gst_element_query (GstElement * element, GstQuery * query)
1588 GstElementClass *oclass;
1589 gboolean result = FALSE;
1591 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1592 g_return_val_if_fail (query != NULL, FALSE);
1594 oclass = GST_ELEMENT_GET_CLASS (element);
1596 if (oclass->query) {
1597 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1598 GST_ELEMENT_NAME (element));
1599 result = oclass->query (element, query);
1601 result = gst_element_default_query (element, query);
1607 * gst_element_post_message:
1608 * @element: a #GstElement posting the message
1609 * @message: a #GstMessage to post
1611 * Post a message on the element's #GstBus. This function takes ownership of the
1612 * message; if you want to access the message after this call, you should add an
1613 * additional reference before calling.
1615 * Returns: %TRUE if the message was successfully posted. The function returns
1616 * %FALSE if the element did not have a bus.
1621 gst_element_post_message (GstElement * element, GstMessage * message)
1624 gboolean result = FALSE;
1626 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1627 g_return_val_if_fail (message != NULL, FALSE);
1629 GST_OBJECT_LOCK (element);
1632 if (G_UNLIKELY (bus == NULL))
1635 gst_object_ref (bus);
1636 GST_OBJECT_UNLOCK (element);
1638 /* we release the element lock when posting the message so that any
1639 * (synchronous) message handlers can operate on the element */
1640 result = gst_bus_post (bus, message);
1641 gst_object_unref (bus);
1648 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1649 "not posting message %p: no bus", message);
1650 GST_OBJECT_UNLOCK (element);
1651 gst_message_unref (message);
1657 * _gst_element_error_printf:
1658 * @format: the printf-like format to use, or %NULL
1660 * This function is only used internally by the gst_element_error() macro.
1662 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1667 _gst_element_error_printf (const gchar * format, ...)
1677 va_start (args, format);
1678 buffer = g_strdup_vprintf (format, args);
1684 * gst_element_message_full:
1685 * @element: a #GstElement to send message from
1686 * @type: the #GstMessageType
1687 * @domain: the GStreamer GError domain this message belongs to
1688 * @code: the GError code belonging to the domain
1689 * @text: an allocated text string to be used as a replacement for the
1690 * default message connected to code, or %NULL
1691 * @debug: an allocated debug message to be used as a replacement for the
1692 * default debugging information, or %NULL
1693 * @file: the source code file where the error was generated
1694 * @function: the source code function where the error was generated
1695 * @line: the source code line where the error was generated
1697 * Post an error, warning or info message on the bus from inside an element.
1699 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1700 * #GST_MESSAGE_INFO.
1704 void gst_element_message_full
1705 (GstElement * element, GstMessageType type,
1706 GQuark domain, gint code, gchar * text,
1707 gchar * debug, const gchar * file, const gchar * function, gint line)
1709 GError *gerror = NULL;
1713 gboolean has_debug = TRUE;
1714 GstMessage *message = NULL;
1717 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1718 g_return_if_fail (GST_IS_ELEMENT (element));
1719 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1720 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1722 /* check if we send the given text or the default error text */
1723 if ((text == NULL) || (text[0] == 0)) {
1724 /* text could have come from g_strdup_printf (""); */
1726 sent_text = gst_error_get_message (domain, code);
1730 /* construct a sent_debug with extra information from source */
1731 if ((debug == NULL) || (debug[0] == 0)) {
1732 /* debug could have come from g_strdup_printf (""); */
1736 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1738 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1739 file, line, function, name, debug);
1741 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1742 file, line, function, name);
1746 /* create gerror and post message */
1747 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1749 gerror = g_error_new_literal (domain, code, sent_text);
1752 case GST_MESSAGE_ERROR:
1754 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1756 case GST_MESSAGE_WARNING:
1757 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1760 case GST_MESSAGE_INFO:
1761 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1765 g_assert_not_reached ();
1768 gst_element_post_message (element, message);
1770 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1771 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1774 g_error_free (gerror);
1775 g_free (sent_debug);
1780 * gst_element_is_locked_state:
1781 * @element: a #GstElement.
1783 * Checks if the state of an element is locked.
1784 * If the state of an element is locked, state changes of the parent don't
1785 * affect the element.
1786 * This way you can leave currently unused elements inside bins. Just lock their
1787 * state before changing the state from #GST_STATE_NULL.
1791 * Returns: TRUE, if the element's state is locked.
1794 gst_element_is_locked_state (GstElement * element)
1798 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1800 GST_OBJECT_LOCK (element);
1801 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1802 GST_OBJECT_UNLOCK (element);
1808 * gst_element_set_locked_state:
1809 * @element: a #GstElement
1810 * @locked_state: TRUE to lock the element's state
1812 * Locks the state of an element, so state changes of the parent don't affect
1813 * this element anymore.
1817 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1818 * or the elements state-locking needed no change.
1821 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1825 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1827 GST_OBJECT_LOCK (element);
1828 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1830 if (G_UNLIKELY (old == locked_state))
1834 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1835 GST_ELEMENT_NAME (element));
1836 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1838 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1839 GST_ELEMENT_NAME (element));
1840 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1842 GST_OBJECT_UNLOCK (element);
1848 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1849 GST_ELEMENT_NAME (element), old);
1850 GST_OBJECT_UNLOCK (element);
1857 * gst_element_sync_state_with_parent:
1858 * @element: a #GstElement.
1860 * Tries to change the state of the element to the same as its parent.
1861 * If this function returns FALSE, the state of element is undefined.
1863 * Returns: TRUE, if the element's state could be synced to the parent's state.
1868 gst_element_sync_state_with_parent (GstElement * element)
1872 GstStateChangeReturn ret;
1874 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1876 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1877 GstState parent_current, parent_pending;
1879 GST_OBJECT_LOCK (parent);
1880 parent_current = GST_STATE (parent);
1881 parent_pending = GST_STATE_PENDING (parent);
1882 GST_OBJECT_UNLOCK (parent);
1884 /* set to pending if there is one, else we set it to the current state of
1886 if (parent_pending != GST_STATE_VOID_PENDING)
1887 target = parent_pending;
1889 target = parent_current;
1891 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1892 "syncing state (%s) to parent %s %s (%s, %s)",
1893 gst_element_state_get_name (GST_STATE (element)),
1894 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1895 gst_element_state_get_name (parent_current),
1896 gst_element_state_get_name (parent_pending));
1898 ret = gst_element_set_state (element, target);
1899 if (ret == GST_STATE_CHANGE_FAILURE)
1902 gst_object_unref (parent);
1906 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1913 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1914 "syncing state failed (%s)",
1915 gst_element_state_change_return_get_name (ret));
1916 gst_object_unref (parent);
1922 static GstStateChangeReturn
1923 gst_element_get_state_func (GstElement * element,
1924 GstState * state, GstState * pending, GstClockTime timeout)
1926 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1927 GstState old_pending;
1929 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1930 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1932 GST_OBJECT_LOCK (element);
1933 ret = GST_STATE_RETURN (element);
1934 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1935 gst_element_state_change_return_get_name (ret));
1937 /* we got an error, report immediately */
1938 if (ret == GST_STATE_CHANGE_FAILURE)
1941 /* we got no_preroll, report immediatly */
1942 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1945 /* no need to wait async if we are not async */
1946 if (ret != GST_STATE_CHANGE_ASYNC)
1949 old_pending = GST_STATE_PENDING (element);
1950 if (old_pending != GST_STATE_VOID_PENDING) {
1951 GTimeVal *timeval, abstimeout;
1954 if (timeout != GST_CLOCK_TIME_NONE) {
1955 glong add = timeout / 1000;
1960 /* make timeout absolute */
1961 g_get_current_time (&abstimeout);
1962 g_time_val_add (&abstimeout, add);
1963 timeval = &abstimeout;
1967 /* get cookie to detect state changes during waiting */
1968 cookie = element->state_cookie;
1970 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1971 "waiting for element to commit state");
1973 /* we have a pending state change, wait for it to complete */
1974 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1975 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1976 /* timeout triggered */
1977 ret = GST_STATE_CHANGE_ASYNC;
1979 if (cookie != element->state_cookie)
1982 /* could be success or failure */
1983 if (old_pending == GST_STATE (element)) {
1984 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1985 ret = GST_STATE_CHANGE_SUCCESS;
1987 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1988 ret = GST_STATE_CHANGE_FAILURE;
1991 /* if nothing is pending anymore we can return SUCCESS */
1992 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1993 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1994 ret = GST_STATE_CHANGE_SUCCESS;
2000 *state = GST_STATE (element);
2002 *pending = GST_STATE_PENDING (element);
2004 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2005 "state current: %s, pending: %s, result: %s",
2006 gst_element_state_get_name (GST_STATE (element)),
2007 gst_element_state_get_name (GST_STATE_PENDING (element)),
2008 gst_element_state_change_return_get_name (ret));
2009 GST_OBJECT_UNLOCK (element);
2016 *state = GST_STATE_VOID_PENDING;
2018 *pending = GST_STATE_VOID_PENDING;
2020 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2022 GST_OBJECT_UNLOCK (element);
2024 return GST_STATE_CHANGE_FAILURE;
2029 * gst_element_get_state:
2030 * @element: a #GstElement to get the state of.
2031 * @state: (out): a pointer to #GstState to hold the state. Can be %NULL.
2032 * @pending: (out): a pointer to #GstState to hold the pending state.
2034 * @timeout: a #GstClockTime to specify the timeout for an async
2035 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2037 * Gets the state of the element.
2039 * For elements that performed an ASYNC state change, as reported by
2040 * gst_element_set_state(), this function will block up to the
2041 * specified timeout value for the state change to complete.
2042 * If the element completes the state change or goes into
2043 * an error, this function returns immediately with a return value of
2044 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2046 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2047 * returns the current and pending state immediately.
2049 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2050 * successfully changed its state but is not able to provide data yet.
2051 * This mostly happens for live sources that only produce data in
2052 * %GST_STATE_PLAYING. While the state change return is equivalent to
2053 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2054 * some sink elements might not be able to complete their state change because
2055 * an element is not producing data to complete the preroll. When setting the
2056 * element to playing, the preroll will complete and playback will start.
2058 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2059 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2060 * element is still performing a state change or
2061 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2065 GstStateChangeReturn
2066 gst_element_get_state (GstElement * element,
2067 GstState * state, GstState * pending, GstClockTime timeout)
2069 GstElementClass *oclass;
2070 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2072 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2074 oclass = GST_ELEMENT_GET_CLASS (element);
2076 if (oclass->get_state)
2077 result = (oclass->get_state) (element, state, pending, timeout);
2083 * gst_element_abort_state:
2084 * @element: a #GstElement to abort the state of.
2086 * Abort the state change of the element. This function is used
2087 * by elements that do asynchronous state changes and find out
2088 * something is wrong.
2090 * This function should be called with the STATE_LOCK held.
2095 gst_element_abort_state (GstElement * element)
2099 #ifndef GST_DISABLE_GST_DEBUG
2103 g_return_if_fail (GST_IS_ELEMENT (element));
2105 GST_OBJECT_LOCK (element);
2106 pending = GST_STATE_PENDING (element);
2108 if (pending == GST_STATE_VOID_PENDING ||
2109 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2110 goto nothing_aborted;
2112 #ifndef GST_DISABLE_GST_DEBUG
2113 old_state = GST_STATE (element);
2115 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2116 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2117 gst_element_state_get_name (pending));
2121 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2123 GST_STATE_BROADCAST (element);
2124 GST_OBJECT_UNLOCK (element);
2130 GST_OBJECT_UNLOCK (element);
2136 * gst_element_continue_state:
2137 * @element: a #GstElement to continue the state change of.
2138 * @ret: The previous state return value
2140 * Commit the state change of the element and proceed to the next
2141 * pending state if any. This function is used
2142 * by elements that do asynchronous state changes.
2143 * The core will normally call this method automatically when an
2144 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2146 * If after calling this method the element still has not reached
2147 * the pending state, the next state change is performed.
2149 * This method is used internally and should normally not be called by plugins
2152 * Returns: The result of the commit state change.
2156 GstStateChangeReturn
2157 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2159 GstStateChangeReturn old_ret;
2160 GstState old_state, old_next;
2161 GstState current, next, pending;
2162 GstMessage *message;
2163 GstStateChange transition;
2165 GST_OBJECT_LOCK (element);
2166 old_ret = GST_STATE_RETURN (element);
2167 GST_STATE_RETURN (element) = ret;
2168 pending = GST_STATE_PENDING (element);
2170 /* check if there is something to commit */
2171 if (pending == GST_STATE_VOID_PENDING)
2172 goto nothing_pending;
2174 old_state = GST_STATE (element);
2175 /* this is the state we should go to next */
2176 old_next = GST_STATE_NEXT (element);
2177 /* update current state */
2178 current = GST_STATE (element) = old_next;
2180 /* see if we reached the final state */
2181 if (pending == current)
2184 next = GST_STATE_GET_NEXT (current, pending);
2185 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2187 GST_STATE_NEXT (element) = next;
2189 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2190 GST_OBJECT_UNLOCK (element);
2192 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2193 "committing state from %s to %s, pending %s, next %s",
2194 gst_element_state_get_name (old_state),
2195 gst_element_state_get_name (old_next),
2196 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2198 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2199 old_state, old_next, pending);
2200 gst_element_post_message (element, message);
2202 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2203 "continue state change %s to %s, final %s",
2204 gst_element_state_get_name (current),
2205 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2207 ret = gst_element_change_state (element, transition);
2213 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2214 GST_OBJECT_UNLOCK (element);
2219 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2220 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2222 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2223 "completed state change to %s", gst_element_state_get_name (pending));
2224 GST_OBJECT_UNLOCK (element);
2226 /* don't post silly messages with the same state. This can happen
2227 * when an element state is changed to what it already was. For bins
2228 * this can be the result of a lost state, which we check with the
2229 * previous return value.
2230 * We do signal the cond though as a _get_state() might be blocking
2232 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2233 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2234 "posting state-changed %s to %s",
2235 gst_element_state_get_name (old_state),
2236 gst_element_state_get_name (old_next));
2238 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2239 old_next, GST_STATE_VOID_PENDING);
2240 gst_element_post_message (element, message);
2243 GST_STATE_BROADCAST (element);
2250 * gst_element_lost_state_full:
2251 * @element: a #GstElement the state is lost of
2252 * @new_base_time: if a new base time should be distributed
2254 * Brings the element to the lost state. The current state of the
2255 * element is copied to the pending state so that any call to
2256 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2258 * An ASYNC_START message is posted with indication to distribute a new
2259 * base_time to the element when @new_base_time is %TRUE.
2260 * If the element was PLAYING, it will go to PAUSED. The element
2261 * will be restored to its PLAYING state by the parent pipeline when it
2264 * This is mostly used for elements that lost their preroll buffer
2265 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2266 * they will go to their pending state again when a new preroll buffer is
2267 * queued. This function can only be called when the element is currently
2268 * not in error or an async state change.
2270 * This function is used internally and should normally not be called from
2271 * plugins or applications.
2278 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2280 GstState old_state, new_state;
2281 GstMessage *message;
2283 g_return_if_fail (GST_IS_ELEMENT (element));
2285 GST_OBJECT_LOCK (element);
2286 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2289 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2290 goto only_async_start;
2292 old_state = GST_STATE (element);
2294 /* when we were PLAYING, the new state is PAUSED. We will also not
2295 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2296 * when we preroll. */
2297 if (old_state > GST_STATE_PAUSED)
2298 new_state = GST_STATE_PAUSED;
2300 new_state = old_state;
2302 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2303 "lost state of %s to %s", gst_element_state_get_name (old_state),
2304 gst_element_state_get_name (new_state));
2306 GST_STATE (element) = new_state;
2307 GST_STATE_NEXT (element) = new_state;
2308 GST_STATE_PENDING (element) = new_state;
2309 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2311 GST_ELEMENT_START_TIME (element) = 0;
2312 GST_OBJECT_UNLOCK (element);
2314 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2315 new_state, new_state, new_state);
2316 gst_element_post_message (element, message);
2319 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2320 gst_element_post_message (element, message);
2326 GST_OBJECT_UNLOCK (element);
2331 GST_OBJECT_UNLOCK (element);
2333 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2334 gst_element_post_message (element, message);
2340 * gst_element_lost_state:
2341 * @element: a #GstElement the state is lost of
2343 * Brings the element to the lost state. This function calls
2344 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2346 * This function is used internally and should normally not be called from
2347 * plugins or applications.
2352 gst_element_lost_state (GstElement * element)
2354 gst_element_lost_state_full (element, TRUE);
2358 * gst_element_set_state:
2359 * @element: a #GstElement to change state of.
2360 * @state: the element's new #GstState.
2362 * Sets the state of the element. This function will try to set the
2363 * requested state by going through all the intermediary states and calling
2364 * the class's state change function for each.
2366 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2367 * element will perform the remainder of the state change asynchronously in
2369 * An application can use gst_element_get_state() to wait for the completion
2370 * of the state change or it can wait for a state change message on the bus.
2372 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2373 * #GST_STATE_CHANGE_ASYNC.
2375 * Returns: Result of the state change using #GstStateChangeReturn.
2379 GstStateChangeReturn
2380 gst_element_set_state (GstElement * element, GstState state)
2382 GstElementClass *oclass;
2383 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2385 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2387 oclass = GST_ELEMENT_GET_CLASS (element);
2389 if (oclass->set_state)
2390 result = (oclass->set_state) (element, state);
2396 * default set state function, calculates the next state based
2397 * on current state and calls the change_state function
2399 static GstStateChangeReturn
2400 gst_element_set_state_func (GstElement * element, GstState state)
2402 GstState current, next, old_pending;
2403 GstStateChangeReturn ret;
2404 GstStateChange transition;
2405 GstStateChangeReturn old_ret;
2407 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2409 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2410 gst_element_state_get_name (state));
2412 /* state lock is taken to protect the set_state() and get_state()
2413 * procedures, it does not lock any variables. */
2414 GST_STATE_LOCK (element);
2416 /* now calculate how to get to the new state */
2417 GST_OBJECT_LOCK (element);
2418 old_ret = GST_STATE_RETURN (element);
2419 /* previous state change returned an error, remove all pending
2420 * and next states */
2421 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2422 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2423 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2424 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2427 current = GST_STATE (element);
2428 next = GST_STATE_NEXT (element);
2429 old_pending = GST_STATE_PENDING (element);
2431 /* this is the (new) state we should go to. TARGET is the last state we set on
2433 if (state != GST_STATE_TARGET (element)) {
2434 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2435 "setting target state to %s", gst_element_state_get_name (state));
2436 GST_STATE_TARGET (element) = state;
2437 /* increment state cookie so that we can track each state change. We only do
2438 * this if this is actually a new state change. */
2439 element->state_cookie++;
2441 GST_STATE_PENDING (element) = state;
2443 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2444 "current %s, old_pending %s, next %s, old return %s",
2445 gst_element_state_get_name (current),
2446 gst_element_state_get_name (old_pending),
2447 gst_element_state_get_name (next),
2448 gst_element_state_change_return_get_name (old_ret));
2450 /* if the element was busy doing a state change, we just update the
2451 * target state, it'll get to it async then. */
2452 if (old_pending != GST_STATE_VOID_PENDING) {
2453 /* upwards state change will happen ASYNC */
2454 if (old_pending <= state)
2456 /* element is going to this state already */
2457 else if (next == state)
2459 /* element was performing an ASYNC upward state change and
2460 * we request to go downward again. Start from the next pending
2462 else if (next > state
2463 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2467 next = GST_STATE_GET_NEXT (current, state);
2468 /* now we store the next state */
2469 GST_STATE_NEXT (element) = next;
2470 /* mark busy, we need to check that there is actually a state change
2471 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2472 * the default element change_state function has no way to know what the
2473 * old value was... could consider this a FIXME...*/
2474 if (current != next)
2475 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2477 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2479 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2480 "%s: setting state from %s to %s",
2481 (next != state ? "intermediate" : "final"),
2482 gst_element_state_get_name (current), gst_element_state_get_name (next));
2484 /* now signal any waiters, they will error since the cookie was incremented */
2485 GST_STATE_BROADCAST (element);
2487 GST_OBJECT_UNLOCK (element);
2489 ret = gst_element_change_state (element, transition);
2491 GST_STATE_UNLOCK (element);
2493 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2494 gst_element_state_change_return_get_name (ret));
2500 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2501 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2502 "element was busy with async state change");
2503 GST_OBJECT_UNLOCK (element);
2505 GST_STATE_UNLOCK (element);
2507 return GST_STATE_CHANGE_ASYNC;
2512 * gst_element_change_state:
2513 * @element: a #GstElement
2514 * @transition: the requested transition
2516 * Perform @transition on @element.
2518 * This function must be called with STATE_LOCK held and is mainly used
2521 * Returns: the #GstStateChangeReturn of the state transition.
2523 GstStateChangeReturn
2524 gst_element_change_state (GstElement * element, GstStateChange transition)
2526 GstElementClass *oclass;
2527 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2529 oclass = GST_ELEMENT_GET_CLASS (element);
2531 /* call the state change function so it can set the state */
2532 if (oclass->change_state)
2533 ret = (oclass->change_state) (element, transition);
2535 ret = GST_STATE_CHANGE_FAILURE;
2538 case GST_STATE_CHANGE_FAILURE:
2539 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2540 "have FAILURE change_state return");
2541 /* state change failure */
2542 gst_element_abort_state (element);
2544 case GST_STATE_CHANGE_ASYNC:
2548 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2549 "element will change state ASYNC");
2551 target = GST_STATE_TARGET (element);
2553 if (target > GST_STATE_READY)
2556 /* else we just continue the state change downwards */
2557 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2558 "forcing commit state %s <= %s",
2559 gst_element_state_get_name (target),
2560 gst_element_state_get_name (GST_STATE_READY));
2562 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2565 case GST_STATE_CHANGE_SUCCESS:
2566 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2567 "element changed state SUCCESS");
2568 /* we can commit the state now which will proceeed to
2570 ret = gst_element_continue_state (element, ret);
2572 case GST_STATE_CHANGE_NO_PREROLL:
2573 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2574 "element changed state NO_PREROLL");
2575 /* we can commit the state now which will proceeed to
2577 ret = gst_element_continue_state (element, ret);
2580 goto invalid_return;
2583 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2588 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2596 GST_OBJECT_LOCK (element);
2597 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2598 g_critical ("%s: unknown return value %d from a state change function",
2599 GST_ELEMENT_NAME (element), ret);
2601 /* we are in error now */
2602 ret = GST_STATE_CHANGE_FAILURE;
2603 GST_STATE_RETURN (element) = ret;
2604 GST_OBJECT_UNLOCK (element);
2610 /* gst_iterator_fold functions for pads_activate
2611 * Note how we don't stop the iterator when we fail an activation. This is
2612 * probably a FIXME since when one pad activation fails, we don't want to
2613 * continue our state change. */
2615 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2617 if (!gst_pad_set_active (pad, *active))
2618 g_value_set_boolean (ret, FALSE);
2620 /* unref the object that was reffed for us by _fold */
2621 gst_object_unref (pad);
2625 /* set the caps on the pad to NULL */
2627 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2629 gst_pad_set_caps (pad, NULL);
2630 gst_object_unref (pad);
2634 /* returns false on error or early cutout (will never happen because the fold
2635 * function always returns TRUE, see FIXME above) of the fold, true if all
2636 * pads in @iter were (de)activated successfully. */
2638 iterator_activate_fold_with_resync (GstIterator * iter,
2639 GstIteratorFoldFunction func, gpointer user_data)
2641 GstIteratorResult ires;
2644 /* no need to unset this later, it's just a boolean */
2645 g_value_init (&ret, G_TYPE_BOOLEAN);
2646 g_value_set_boolean (&ret, TRUE);
2649 ires = gst_iterator_fold (iter, func, &ret, user_data);
2651 case GST_ITERATOR_RESYNC:
2652 /* need to reset the result again */
2653 g_value_set_boolean (&ret, TRUE);
2654 gst_iterator_resync (iter);
2656 case GST_ITERATOR_DONE:
2657 /* all pads iterated, return collected value */
2660 /* iterator returned _ERROR or premature end with _OK,
2661 * mark an error and exit */
2662 g_value_set_boolean (&ret, FALSE);
2667 /* return collected value */
2668 return g_value_get_boolean (&ret);
2671 /* is called with STATE_LOCK
2673 * Pads are activated from source pads to sinkpads.
2676 gst_element_pads_activate (GstElement * element, gboolean active)
2681 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2682 "pads_activate with active %d", active);
2684 iter = gst_element_iterate_src_pads (element);
2686 iterator_activate_fold_with_resync (iter,
2687 (GstIteratorFoldFunction) activate_pads, &active);
2688 gst_iterator_free (iter);
2689 if (G_UNLIKELY (!res))
2692 iter = gst_element_iterate_sink_pads (element);
2694 iterator_activate_fold_with_resync (iter,
2695 (GstIteratorFoldFunction) activate_pads, &active);
2696 gst_iterator_free (iter);
2697 if (G_UNLIKELY (!res))
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) clear_caps, &active);
2706 gst_iterator_free (iter);
2707 if (G_UNLIKELY (!res))
2711 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2712 "pads_activate successful");
2719 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2720 "source pads_activate failed");
2725 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2726 "sink pads_activate failed");
2731 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2732 "failed to clear caps on pads");
2737 /* is called with STATE_LOCK */
2738 static GstStateChangeReturn
2739 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2741 GstState state, next;
2742 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2745 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2747 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2748 next = GST_STATE_TRANSITION_NEXT (transition);
2750 /* if the element already is in the given state, we just return success */
2751 if (next == GST_STATE_VOID_PENDING || state == next)
2754 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2755 "default handler tries setting state from %s to %s (%04x)",
2756 gst_element_state_get_name (state),
2757 gst_element_state_get_name (next), transition);
2759 switch (transition) {
2760 case GST_STATE_CHANGE_NULL_TO_READY:
2762 case GST_STATE_CHANGE_READY_TO_PAUSED:
2763 if (!gst_element_pads_activate (element, TRUE)) {
2764 result = GST_STATE_CHANGE_FAILURE;
2767 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2769 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2771 case GST_STATE_CHANGE_PAUSED_TO_READY:
2772 case GST_STATE_CHANGE_READY_TO_NULL:
2773 /* deactivate pads in both cases, since they are activated on
2774 ready->paused but the element might not have made it to paused */
2775 if (!gst_element_pads_activate (element, FALSE)) {
2776 result = GST_STATE_CHANGE_FAILURE;
2778 gst_element_set_base_time (element, 0);
2781 /* In null state release the reference to the clock */
2782 GST_OBJECT_LOCK (element);
2783 clock_p = &element->clock;
2784 gst_object_replace ((GstObject **) clock_p, NULL);
2785 GST_OBJECT_UNLOCK (element);
2788 /* this will catch real but unhandled state changes;
2789 * can only be caused by:
2790 * - a new state was added
2791 * - somehow the element was asked to jump across an intermediate state
2793 g_warning ("Unhandled state change from %s to %s",
2794 gst_element_state_get_name (state),
2795 gst_element_state_get_name (next));
2802 GST_OBJECT_LOCK (element);
2803 result = GST_STATE_RETURN (element);
2804 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2805 "element is already in the %s state",
2806 gst_element_state_get_name (state));
2807 GST_OBJECT_UNLOCK (element);
2814 * gst_element_get_factory:
2815 * @element: a #GstElement to request the element factory of.
2817 * Retrieves the factory that was used to create this element.
2819 * Returns: the #GstElementFactory used for creating this element.
2820 * no refcounting is needed.
2823 gst_element_get_factory (GstElement * element)
2825 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2827 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2831 gst_element_dispose (GObject * object)
2833 GstElement *element = GST_ELEMENT_CAST (object);
2837 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2839 if (GST_STATE (element) != GST_STATE_NULL)
2842 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2843 "removing %d pads", g_list_length (element->pads));
2844 /* first we break all our links with the outside */
2845 while (element->pads && element->pads->data) {
2846 /* don't call _remove_pad with NULL */
2847 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2849 if (G_UNLIKELY (element->pads != NULL)) {
2850 g_critical ("could not remove pads from element %s",
2851 GST_STR_NULL (GST_OBJECT_NAME (object)));
2854 GST_OBJECT_LOCK (element);
2855 clock_p = &element->clock;
2856 bus_p = &element->bus;
2857 gst_object_replace ((GstObject **) clock_p, NULL);
2858 gst_object_replace ((GstObject **) bus_p, NULL);
2859 GST_OBJECT_UNLOCK (element);
2861 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2863 G_OBJECT_CLASS (parent_class)->dispose (object);
2872 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2874 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2876 "You need to explicitly set elements to the NULL state before\n"
2877 "dropping the final reference, to allow them to clean up.\n"
2878 "This problem may also be caused by a refcounting bug in the\n"
2879 "application or some element.\n",
2880 GST_OBJECT_NAME (element),
2881 gst_element_state_get_name (GST_STATE (element)),
2882 is_locked ? " (locked)" : "");
2888 gst_element_finalize (GObject * object)
2890 GstElement *element = GST_ELEMENT_CAST (object);
2892 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2894 GST_STATE_LOCK (element);
2895 if (element->state_cond)
2896 g_cond_free (element->state_cond);
2897 element->state_cond = NULL;
2898 GST_STATE_UNLOCK (element);
2899 g_static_rec_mutex_free (element->state_lock);
2900 g_slice_free (GStaticRecMutex, element->state_lock);
2901 element->state_lock = NULL;
2903 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2905 G_OBJECT_CLASS (parent_class)->finalize (object);
2908 #ifndef GST_DISABLE_LOADSAVE
2910 * gst_element_save_thyself:
2911 * @element: a #GstElement to save.
2912 * @parent: the xml parent node.
2914 * Saves the element as part of the given XML structure.
2916 * Returns: the new #xmlNodePtr.
2919 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2922 GstElementClass *oclass;
2923 GParamSpec **specs, *spec;
2926 GValue value = { 0, };
2927 GstElement *element;
2929 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2931 element = GST_ELEMENT_CAST (object);
2933 oclass = GST_ELEMENT_GET_CLASS (element);
2935 xmlNewChild (parent, NULL, (xmlChar *) "name",
2936 (xmlChar *) GST_ELEMENT_NAME (element));
2938 if (oclass->elementfactory != NULL) {
2939 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2941 xmlNewChild (parent, NULL, (xmlChar *) "type",
2942 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2946 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2948 for (i = 0; i < nspecs; i++) {
2950 if (spec->flags & G_PARAM_READABLE) {
2954 g_value_init (&value, spec->value_type);
2956 g_object_get_property (G_OBJECT (element), spec->name, &value);
2957 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2958 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2960 if (G_IS_PARAM_SPEC_STRING (spec))
2961 contents = g_value_dup_string (&value);
2962 else if (G_IS_PARAM_SPEC_ENUM (spec))
2963 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2964 else if (G_IS_PARAM_SPEC_INT64 (spec))
2965 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2966 g_value_get_int64 (&value));
2967 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
2968 if (g_value_get_boxed (&value) != NULL) {
2969 contents = g_strdup_value_contents (&value);
2971 contents = g_strdup ("NULL");
2974 contents = g_strdup_value_contents (&value);
2976 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2979 g_value_unset (&value);
2985 pads = g_list_last (GST_ELEMENT_PADS (element));
2988 GstPad *pad = GST_PAD_CAST (pads->data);
2990 /* figure out if it's a direct pad or a ghostpad */
2991 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
2992 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
2994 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
2996 pads = g_list_previous (pads);
3003 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3005 xmlNodePtr children;
3006 GstElement *element;
3008 gchar *value = NULL;
3010 element = GST_ELEMENT_CAST (object);
3011 g_return_if_fail (element != NULL);
3014 children = self->xmlChildrenNode;
3016 if (!strcmp ((char *) children->name, "param")) {
3017 xmlNodePtr child = children->xmlChildrenNode;
3020 if (!strcmp ((char *) child->name, "name")) {
3021 name = (gchar *) xmlNodeGetContent (child);
3022 } else if (!strcmp ((char *) child->name, "value")) {
3023 value = (gchar *) xmlNodeGetContent (child);
3025 child = child->next;
3027 /* FIXME: can this just be g_object_set ? */
3028 gst_util_set_object_arg (G_OBJECT (element), name, value);
3029 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3033 children = children->next;
3037 children = self->xmlChildrenNode;
3039 if (!strcmp ((char *) children->name, "pad")) {
3040 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3042 children = children->next;
3045 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3046 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3048 #endif /* GST_DISABLE_LOADSAVE */
3051 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3055 g_return_if_fail (GST_IS_ELEMENT (element));
3057 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3059 GST_OBJECT_LOCK (element);
3060 bus_p = &GST_ELEMENT_BUS (element);
3061 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3062 GST_OBJECT_UNLOCK (element);
3066 * gst_element_set_bus:
3067 * @element: a #GstElement to set the bus of.
3068 * @bus: the #GstBus to set.
3070 * Sets the bus of the element. Increases the refcount on the bus.
3071 * For internal use only, unless you're testing elements.
3076 gst_element_set_bus (GstElement * element, GstBus * bus)
3078 GstElementClass *oclass;
3080 g_return_if_fail (GST_IS_ELEMENT (element));
3082 oclass = GST_ELEMENT_GET_CLASS (element);
3084 if (oclass->set_bus)
3085 oclass->set_bus (element, bus);
3089 * gst_element_get_bus:
3090 * @element: a #GstElement to get the bus of.
3092 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3093 * bus for the application.
3095 * Returns: the element's #GstBus. unref after usage.
3100 gst_element_get_bus (GstElement * element)
3102 GstBus *result = NULL;
3104 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3106 GST_OBJECT_LOCK (element);
3107 if ((result = GST_ELEMENT_BUS (element)))
3108 gst_object_ref (result);
3109 GST_OBJECT_UNLOCK (element);
3111 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,