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;
991 gchar *str, *endptr = NULL;
992 GstElementClass *class;
994 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
995 g_return_val_if_fail (name != NULL, NULL);
997 class = GST_ELEMENT_GET_CLASS (element);
999 /* if the name contains a %, we assume it's the complete template name. Get
1000 * the template and try to get a pad */
1001 if (strstr (name, "%")) {
1002 templ = gst_element_class_get_request_pad_template (class, name);
1007 /* there is no % in the name, try to find a matching template */
1008 list = class->padtemplates;
1009 while (!templ_found && list) {
1010 templ = (GstPadTemplate *) list->data;
1011 if (templ->presence == GST_PAD_REQUEST) {
1012 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1013 templ->name_template);
1014 /* see if we find an exact match */
1015 if (strcmp (name, templ->name_template) == 0) {
1020 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1021 and %d, occurring at the end of the name_template, are the only
1023 else if ((str = strchr (templ->name_template, '%'))
1024 && strncmp (templ->name_template, name,
1025 str - templ->name_template) == 0
1026 && strlen (name) > str - templ->name_template) {
1027 data = name + (str - templ->name_template);
1028 if (*(str + 1) == 'd') {
1030 n = (gint) strtol (data, &endptr, 10);
1031 if (endptr && *endptr == '\0') {
1051 pad = gst_element_request_pad (element, templ, req_name);
1057 * gst_element_get_pad:
1058 * @element: a #GstElement.
1059 * @name: the name of the pad to retrieve.
1061 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1062 * first, then gst_element_get_request_pad().
1064 * Deprecated: This function is deprecated as it's unclear if the reference
1065 * to the result pad should be released with gst_object_unref() in case of a static pad
1066 * or gst_element_release_request_pad() in case of a request pad.
1067 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1069 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1070 * depending on the type of the pad.
1072 #ifndef GST_REMOVE_DEPRECATED
1073 #ifdef GST_DISABLE_DEPRECATED
1074 GstPad *gst_element_get_pad (GstElement * element, const gchar * name);
1077 gst_element_get_pad (GstElement * element, const gchar * name)
1081 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1082 g_return_val_if_fail (name != NULL, NULL);
1084 pad = gst_element_get_static_pad (element, name);
1086 pad = gst_element_get_request_pad (element, name);
1090 #endif /* GST_REMOVE_DEPRECATED */
1092 static GstIteratorItem
1093 iterate_pad (GstIterator * it, GstPad * pad)
1095 gst_object_ref (pad);
1096 return GST_ITERATOR_ITEM_PASS;
1099 static GstIterator *
1100 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1102 GstIterator *result;
1104 GST_OBJECT_LOCK (element);
1105 gst_object_ref (element);
1106 result = gst_iterator_new_list (GST_TYPE_PAD,
1107 GST_OBJECT_GET_LOCK (element),
1108 &element->pads_cookie,
1111 (GstIteratorItemFunction) iterate_pad,
1112 (GstIteratorDisposeFunction) gst_object_unref);
1113 GST_OBJECT_UNLOCK (element);
1119 * gst_element_iterate_pads:
1120 * @element: a #GstElement to iterate pads of.
1122 * Retrieves an iterattor of @element's pads. The iterator should
1123 * be freed after usage.
1125 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1130 gst_element_iterate_pads (GstElement * element)
1132 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1134 return gst_element_iterate_pad_list (element, &element->pads);
1138 * gst_element_iterate_src_pads:
1139 * @element: a #GstElement.
1141 * Retrieves an iterator of @element's source pads.
1143 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1148 gst_element_iterate_src_pads (GstElement * element)
1150 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1152 return gst_element_iterate_pad_list (element, &element->srcpads);
1156 * gst_element_iterate_sink_pads:
1157 * @element: a #GstElement.
1159 * Retrieves an iterator of @element's sink pads.
1161 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1166 gst_element_iterate_sink_pads (GstElement * element)
1168 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1170 return gst_element_iterate_pad_list (element, &element->sinkpads);
1174 * gst_element_class_add_pad_template:
1175 * @klass: the #GstElementClass to add the pad template to.
1176 * @templ: a #GstPadTemplate to add to the element class.
1178 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1179 * functions of classes.
1182 gst_element_class_add_pad_template (GstElementClass * klass,
1183 GstPadTemplate * templ)
1185 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1186 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1188 /* FIXME 0.11: allow replacing the pad templates by
1189 * calling this with the same name as an already existing pad
1190 * template. For this we _must_ _not_ ref the added pad template
1191 * a second time and _must_ document that this function takes
1192 * ownership of the pad template. Otherwise we will leak pad templates
1193 * or the caller unref's the pad template and it disappears */
1194 /* avoid registering pad templates with the same name */
1195 g_return_if_fail (gst_element_class_get_pad_template (klass,
1196 templ->name_template) == NULL);
1198 klass->padtemplates = g_list_append (klass->padtemplates,
1199 gst_object_ref (templ));
1200 klass->numpadtemplates++;
1204 * gst_element_class_set_details:
1205 * @klass: class to set details for
1206 * @details: details to set
1208 * Sets the detailed information for a #GstElementClass.
1209 * <note>This function is for use in _base_init functions only.</note>
1211 * The @details are copied.
1213 * Deprecated: Use gst_element_class_set_details_simple() instead.
1215 #ifndef GST_REMOVE_DEPRECATED
1216 #ifdef GST_DISABLE_DEPRECATED
1218 gst_element_class_set_details (GstElementClass * klass,
1219 const GstElementDetails * details);
1222 gst_element_class_set_details (GstElementClass * klass,
1223 const GstElementDetails * details)
1225 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1226 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1228 __gst_element_details_copy (&klass->details, details);
1233 * gst_element_class_set_details_simple:
1234 * @klass: class to set details for
1235 * @longname: The long English name of the element. E.g. "File Sink"
1236 * @classification: String describing the type of element, as an unordered list
1237 * separated with slashes ('/'). See draft-klass.txt of the design docs
1238 * for more details and common types. E.g: "Sink/File"
1239 * @description: Sentence describing the purpose of the element.
1240 * E.g: "Write stream to a file"
1241 * @author: Name and contact details of the author(s). Use \n to separate
1242 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1244 * Sets the detailed information for a #GstElementClass. Simpler version of
1245 * gst_element_class_set_details() that generates less linker overhead.
1246 * <note>This function is for use in _base_init functions only.</note>
1248 * The detail parameter strings are copied into the #GstElementDetails for
1249 * the element class.
1254 gst_element_class_set_details_simple (GstElementClass * klass,
1255 const gchar * longname, const gchar * classification,
1256 const gchar * description, const gchar * author)
1258 const GstElementDetails details =
1259 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1260 (gchar *) description, (gchar *) author);
1262 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1264 __gst_element_details_copy (&klass->details, &details);
1268 * gst_element_class_get_pad_template_list:
1269 * @element_class: a #GstElementClass to get pad templates of.
1271 * Retrieves a list of the pad templates associated with @element_class. The
1272 * list must not be modified by the calling code.
1273 * <note>If you use this function in the #GInstanceInitFunc of an object class
1274 * that has subclasses, make sure to pass the g_class parameter of the
1275 * #GInstanceInitFunc here.</note>
1277 * Returns: the #GList of padtemplates.
1280 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1282 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1284 return element_class->padtemplates;
1288 * gst_element_class_get_pad_template:
1289 * @element_class: a #GstElementClass to get the pad template of.
1290 * @name: the name of the #GstPadTemplate to get.
1292 * Retrieves a padtemplate from @element_class with the given name.
1293 * <note>If you use this function in the #GInstanceInitFunc of an object class
1294 * that has subclasses, make sure to pass the g_class parameter of the
1295 * #GInstanceInitFunc here.</note>
1297 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1298 * No unreferencing is necessary.
1301 gst_element_class_get_pad_template (GstElementClass * element_class,
1306 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1307 g_return_val_if_fail (name != NULL, NULL);
1309 padlist = element_class->padtemplates;
1312 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1314 if (strcmp (padtempl->name_template, name) == 0)
1317 padlist = g_list_next (padlist);
1323 static GstPadTemplate *
1324 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1327 GstPadTemplate *tmpl;
1329 tmpl = gst_element_class_get_pad_template (element_class, name);
1330 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1336 /* get a random pad on element of the given direction.
1337 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1340 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1341 GstPadDirection dir)
1343 GstPad *result = NULL;
1346 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1350 GST_OBJECT_LOCK (element);
1351 pads = element->srcpads;
1354 GST_OBJECT_LOCK (element);
1355 pads = element->sinkpads;
1358 goto wrong_direction;
1360 for (; pads; pads = g_list_next (pads)) {
1361 GstPad *pad = GST_PAD_CAST (pads->data);
1363 GST_OBJECT_LOCK (pad);
1364 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1365 GST_DEBUG_PAD_NAME (pad));
1367 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1368 /* if we require a linked pad, and it is not linked, continue the
1370 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1371 GST_DEBUG_PAD_NAME (pad));
1372 GST_OBJECT_UNLOCK (pad);
1375 /* found a pad, stop search */
1376 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1377 GST_DEBUG_PAD_NAME (pad));
1378 GST_OBJECT_UNLOCK (pad);
1384 gst_object_ref (result);
1386 GST_OBJECT_UNLOCK (element);
1390 /* ERROR handling */
1393 g_warning ("unknown pad direction %d", dir);
1399 gst_element_default_send_event (GstElement * element, GstEvent * event)
1401 gboolean result = FALSE;
1404 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1405 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1406 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1409 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1410 "pushing %s event to random %s pad %s:%s",
1411 GST_EVENT_TYPE_NAME (event),
1412 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1413 GST_DEBUG_PAD_NAME (pad));
1415 result = gst_pad_push_event (pad, event);
1416 gst_object_unref (pad);
1418 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1419 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1425 * gst_element_send_event:
1426 * @element: a #GstElement to send the event to.
1427 * @event: the #GstEvent to send to the element.
1429 * Sends an event to an element. If the element doesn't implement an
1430 * event handler, the event will be pushed on a random linked sink pad for
1431 * upstream events or a random linked source pad for downstream events.
1433 * This function takes owership of the provided event so you should
1434 * gst_event_ref() it if you want to reuse the event after this call.
1436 * Returns: %TRUE if the event was handled.
1441 gst_element_send_event (GstElement * element, GstEvent * event)
1443 GstElementClass *oclass;
1444 gboolean result = FALSE;
1446 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1447 g_return_val_if_fail (event != NULL, FALSE);
1449 oclass = GST_ELEMENT_GET_CLASS (element);
1451 GST_STATE_LOCK (element);
1452 if (oclass->send_event) {
1453 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1454 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1455 result = oclass->send_event (element, event);
1457 result = gst_element_default_send_event (element, event);
1459 GST_STATE_UNLOCK (element);
1466 * @element: a #GstElement to send the event to.
1467 * @rate: The new playback rate
1468 * @format: The format of the seek values
1469 * @flags: The optional seek flags.
1470 * @cur_type: The type and flags for the new current position
1471 * @cur: The value of the new current position
1472 * @stop_type: The type and flags for the new stop position
1473 * @stop: The value of the new stop position
1475 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1476 * the parameters. The seek event is sent to the element using
1477 * gst_element_send_event().
1479 * Returns: %TRUE if the event was handled.
1484 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1485 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1486 GstSeekType stop_type, gint64 stop)
1491 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1494 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1495 result = gst_element_send_event (element, event);
1501 * gst_element_get_query_types:
1502 * @element: a #GstElement to query
1504 * Get an array of query types from the element.
1505 * If the element doesn't implement a query types function,
1506 * the query will be forwarded to the peer of a random linked sink pad.
1508 * Returns: An array of #GstQueryType elements that should not
1509 * be freed or modified.
1513 const GstQueryType *
1514 gst_element_get_query_types (GstElement * element)
1516 GstElementClass *oclass;
1517 const GstQueryType *result = NULL;
1519 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1521 oclass = GST_ELEMENT_GET_CLASS (element);
1523 if (oclass->get_query_types) {
1524 result = oclass->get_query_types (element);
1526 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1529 GstPad *peer = gst_pad_get_peer (pad);
1532 result = gst_pad_get_query_types (peer);
1534 gst_object_unref (peer);
1536 gst_object_unref (pad);
1543 gst_element_default_query (GstElement * element, GstQuery * query)
1545 gboolean result = FALSE;
1548 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1550 result = gst_pad_query (pad, query);
1552 gst_object_unref (pad);
1554 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1556 GstPad *peer = gst_pad_get_peer (pad);
1559 result = gst_pad_query (peer, query);
1561 gst_object_unref (peer);
1563 gst_object_unref (pad);
1570 * gst_element_query:
1571 * @element: a #GstElement to perform the query on.
1572 * @query: the #GstQuery.
1574 * Performs a query on the given element.
1576 * For elements that don't implement a query handler, this function
1577 * forwards the query to a random srcpad or to the peer of a
1578 * random linked sinkpad of this element.
1580 * Returns: TRUE if the query could be performed.
1585 gst_element_query (GstElement * element, GstQuery * query)
1587 GstElementClass *oclass;
1588 gboolean result = FALSE;
1590 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1591 g_return_val_if_fail (query != NULL, FALSE);
1593 oclass = GST_ELEMENT_GET_CLASS (element);
1595 if (oclass->query) {
1596 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1597 GST_ELEMENT_NAME (element));
1598 result = oclass->query (element, query);
1600 result = gst_element_default_query (element, query);
1606 * gst_element_post_message:
1607 * @element: a #GstElement posting the message
1608 * @message: a #GstMessage to post
1610 * Post a message on the element's #GstBus. This function takes ownership of the
1611 * message; if you want to access the message after this call, you should add an
1612 * additional reference before calling.
1614 * Returns: %TRUE if the message was successfully posted. The function returns
1615 * %FALSE if the element did not have a bus.
1620 gst_element_post_message (GstElement * element, GstMessage * message)
1623 gboolean result = FALSE;
1625 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1626 g_return_val_if_fail (message != NULL, FALSE);
1628 GST_OBJECT_LOCK (element);
1631 if (G_UNLIKELY (bus == NULL))
1634 gst_object_ref (bus);
1635 GST_OBJECT_UNLOCK (element);
1637 /* we release the element lock when posting the message so that any
1638 * (synchronous) message handlers can operate on the element */
1639 result = gst_bus_post (bus, message);
1640 gst_object_unref (bus);
1647 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1648 "not posting message %p: no bus", message);
1649 GST_OBJECT_UNLOCK (element);
1650 gst_message_unref (message);
1656 * _gst_element_error_printf:
1657 * @format: the printf-like format to use, or %NULL
1659 * This function is only used internally by the gst_element_error() macro.
1661 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1666 _gst_element_error_printf (const gchar * format, ...)
1676 va_start (args, format);
1677 buffer = g_strdup_vprintf (format, args);
1683 * gst_element_message_full:
1684 * @element: a #GstElement to send message from
1685 * @type: the #GstMessageType
1686 * @domain: the GStreamer GError domain this message belongs to
1687 * @code: the GError code belonging to the domain
1688 * @text: an allocated text string to be used as a replacement for the
1689 * default message connected to code, or %NULL
1690 * @debug: an allocated debug message to be used as a replacement for the
1691 * default debugging information, or %NULL
1692 * @file: the source code file where the error was generated
1693 * @function: the source code function where the error was generated
1694 * @line: the source code line where the error was generated
1696 * Post an error, warning or info message on the bus from inside an element.
1698 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1699 * #GST_MESSAGE_INFO.
1703 void gst_element_message_full
1704 (GstElement * element, GstMessageType type,
1705 GQuark domain, gint code, gchar * text,
1706 gchar * debug, const gchar * file, const gchar * function, gint line)
1708 GError *gerror = NULL;
1712 gboolean has_debug = TRUE;
1713 GstMessage *message = NULL;
1716 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1717 g_return_if_fail (GST_IS_ELEMENT (element));
1718 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1719 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1721 /* check if we send the given text or the default error text */
1722 if ((text == NULL) || (text[0] == 0)) {
1723 /* text could have come from g_strdup_printf (""); */
1725 sent_text = gst_error_get_message (domain, code);
1729 /* construct a sent_debug with extra information from source */
1730 if ((debug == NULL) || (debug[0] == 0)) {
1731 /* debug could have come from g_strdup_printf (""); */
1735 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1737 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1738 file, line, function, name, debug);
1740 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1741 file, line, function, name);
1745 /* create gerror and post message */
1746 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1748 gerror = g_error_new_literal (domain, code, sent_text);
1751 case GST_MESSAGE_ERROR:
1753 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1755 case GST_MESSAGE_WARNING:
1756 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1759 case GST_MESSAGE_INFO:
1760 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1764 g_assert_not_reached ();
1767 gst_element_post_message (element, message);
1769 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1770 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1773 g_error_free (gerror);
1774 g_free (sent_debug);
1779 * gst_element_is_locked_state:
1780 * @element: a #GstElement.
1782 * Checks if the state of an element is locked.
1783 * If the state of an element is locked, state changes of the parent don't
1784 * affect the element.
1785 * This way you can leave currently unused elements inside bins. Just lock their
1786 * state before changing the state from #GST_STATE_NULL.
1790 * Returns: TRUE, if the element's state is locked.
1793 gst_element_is_locked_state (GstElement * element)
1797 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1799 GST_OBJECT_LOCK (element);
1800 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1801 GST_OBJECT_UNLOCK (element);
1807 * gst_element_set_locked_state:
1808 * @element: a #GstElement
1809 * @locked_state: TRUE to lock the element's state
1811 * Locks the state of an element, so state changes of the parent don't affect
1812 * this element anymore.
1816 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1817 * or the elements state-locking needed no change.
1820 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1824 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1826 GST_OBJECT_LOCK (element);
1827 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1829 if (G_UNLIKELY (old == locked_state))
1833 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1834 GST_ELEMENT_NAME (element));
1835 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1837 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1838 GST_ELEMENT_NAME (element));
1839 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1841 GST_OBJECT_UNLOCK (element);
1847 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1848 GST_ELEMENT_NAME (element), old);
1849 GST_OBJECT_UNLOCK (element);
1856 * gst_element_sync_state_with_parent:
1857 * @element: a #GstElement.
1859 * Tries to change the state of the element to the same as its parent.
1860 * If this function returns FALSE, the state of element is undefined.
1862 * Returns: TRUE, if the element's state could be synced to the parent's state.
1867 gst_element_sync_state_with_parent (GstElement * element)
1871 GstStateChangeReturn ret;
1873 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1875 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1876 GstState parent_current, parent_pending;
1878 GST_OBJECT_LOCK (parent);
1879 parent_current = GST_STATE (parent);
1880 parent_pending = GST_STATE_PENDING (parent);
1881 GST_OBJECT_UNLOCK (parent);
1883 /* set to pending if there is one, else we set it to the current state of
1885 if (parent_pending != GST_STATE_VOID_PENDING)
1886 target = parent_pending;
1888 target = parent_current;
1890 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1891 "syncing state (%s) to parent %s %s (%s, %s)",
1892 gst_element_state_get_name (GST_STATE (element)),
1893 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1894 gst_element_state_get_name (parent_current),
1895 gst_element_state_get_name (parent_pending));
1897 ret = gst_element_set_state (element, target);
1898 if (ret == GST_STATE_CHANGE_FAILURE)
1901 gst_object_unref (parent);
1905 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1912 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1913 "syncing state failed (%s)",
1914 gst_element_state_change_return_get_name (ret));
1915 gst_object_unref (parent);
1921 static GstStateChangeReturn
1922 gst_element_get_state_func (GstElement * element,
1923 GstState * state, GstState * pending, GstClockTime timeout)
1925 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1926 GstState old_pending;
1928 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1929 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1931 GST_OBJECT_LOCK (element);
1932 ret = GST_STATE_RETURN (element);
1933 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1934 gst_element_state_change_return_get_name (ret));
1936 /* we got an error, report immediately */
1937 if (ret == GST_STATE_CHANGE_FAILURE)
1940 /* we got no_preroll, report immediatly */
1941 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1944 /* no need to wait async if we are not async */
1945 if (ret != GST_STATE_CHANGE_ASYNC)
1948 old_pending = GST_STATE_PENDING (element);
1949 if (old_pending != GST_STATE_VOID_PENDING) {
1950 GTimeVal *timeval, abstimeout;
1953 if (timeout != GST_CLOCK_TIME_NONE) {
1954 glong add = timeout / 1000;
1959 /* make timeout absolute */
1960 g_get_current_time (&abstimeout);
1961 g_time_val_add (&abstimeout, add);
1962 timeval = &abstimeout;
1966 /* get cookie to detect state changes during waiting */
1967 cookie = element->state_cookie;
1969 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1970 "waiting for element to commit state");
1972 /* we have a pending state change, wait for it to complete */
1973 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1974 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1975 /* timeout triggered */
1976 ret = GST_STATE_CHANGE_ASYNC;
1978 if (cookie != element->state_cookie)
1981 /* could be success or failure */
1982 if (old_pending == GST_STATE (element)) {
1983 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1984 ret = GST_STATE_CHANGE_SUCCESS;
1986 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1987 ret = GST_STATE_CHANGE_FAILURE;
1990 /* if nothing is pending anymore we can return SUCCESS */
1991 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1992 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1993 ret = GST_STATE_CHANGE_SUCCESS;
1999 *state = GST_STATE (element);
2001 *pending = GST_STATE_PENDING (element);
2003 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2004 "state current: %s, pending: %s, result: %s",
2005 gst_element_state_get_name (GST_STATE (element)),
2006 gst_element_state_get_name (GST_STATE_PENDING (element)),
2007 gst_element_state_change_return_get_name (ret));
2008 GST_OBJECT_UNLOCK (element);
2015 *state = GST_STATE_VOID_PENDING;
2017 *pending = GST_STATE_VOID_PENDING;
2019 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2021 GST_OBJECT_UNLOCK (element);
2023 return GST_STATE_CHANGE_FAILURE;
2028 * gst_element_get_state:
2029 * @element: a #GstElement to get the state of.
2030 * @state: (out): a pointer to #GstState to hold the state. Can be %NULL.
2031 * @pending: (out): a pointer to #GstState to hold the pending state.
2033 * @timeout: a #GstClockTime to specify the timeout for an async
2034 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2036 * Gets the state of the element.
2038 * For elements that performed an ASYNC state change, as reported by
2039 * gst_element_set_state(), this function will block up to the
2040 * specified timeout value for the state change to complete.
2041 * If the element completes the state change or goes into
2042 * an error, this function returns immediately with a return value of
2043 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2045 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2046 * returns the current and pending state immediately.
2048 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2049 * successfully changed its state but is not able to provide data yet.
2050 * This mostly happens for live sources that only produce data in
2051 * %GST_STATE_PLAYING. While the state change return is equivalent to
2052 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2053 * some sink elements might not be able to complete their state change because
2054 * an element is not producing data to complete the preroll. When setting the
2055 * element to playing, the preroll will complete and playback will start.
2057 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2058 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2059 * element is still performing a state change or
2060 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2064 GstStateChangeReturn
2065 gst_element_get_state (GstElement * element,
2066 GstState * state, GstState * pending, GstClockTime timeout)
2068 GstElementClass *oclass;
2069 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2071 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2073 oclass = GST_ELEMENT_GET_CLASS (element);
2075 if (oclass->get_state)
2076 result = (oclass->get_state) (element, state, pending, timeout);
2082 * gst_element_abort_state:
2083 * @element: a #GstElement to abort the state of.
2085 * Abort the state change of the element. This function is used
2086 * by elements that do asynchronous state changes and find out
2087 * something is wrong.
2089 * This function should be called with the STATE_LOCK held.
2094 gst_element_abort_state (GstElement * element)
2098 #ifndef GST_DISABLE_GST_DEBUG
2102 g_return_if_fail (GST_IS_ELEMENT (element));
2104 GST_OBJECT_LOCK (element);
2105 pending = GST_STATE_PENDING (element);
2107 if (pending == GST_STATE_VOID_PENDING ||
2108 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2109 goto nothing_aborted;
2111 #ifndef GST_DISABLE_GST_DEBUG
2112 old_state = GST_STATE (element);
2114 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2115 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2116 gst_element_state_get_name (pending));
2120 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2122 GST_STATE_BROADCAST (element);
2123 GST_OBJECT_UNLOCK (element);
2129 GST_OBJECT_UNLOCK (element);
2135 * gst_element_continue_state:
2136 * @element: a #GstElement to continue the state change of.
2137 * @ret: The previous state return value
2139 * Commit the state change of the element and proceed to the next
2140 * pending state if any. This function is used
2141 * by elements that do asynchronous state changes.
2142 * The core will normally call this method automatically when an
2143 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2145 * If after calling this method the element still has not reached
2146 * the pending state, the next state change is performed.
2148 * This method is used internally and should normally not be called by plugins
2151 * Returns: The result of the commit state change.
2155 GstStateChangeReturn
2156 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2158 GstStateChangeReturn old_ret;
2159 GstState old_state, old_next;
2160 GstState current, next, pending;
2161 GstMessage *message;
2162 GstStateChange transition;
2164 GST_OBJECT_LOCK (element);
2165 old_ret = GST_STATE_RETURN (element);
2166 GST_STATE_RETURN (element) = ret;
2167 pending = GST_STATE_PENDING (element);
2169 /* check if there is something to commit */
2170 if (pending == GST_STATE_VOID_PENDING)
2171 goto nothing_pending;
2173 old_state = GST_STATE (element);
2174 /* this is the state we should go to next */
2175 old_next = GST_STATE_NEXT (element);
2176 /* update current state */
2177 current = GST_STATE (element) = old_next;
2179 /* see if we reached the final state */
2180 if (pending == current)
2183 next = GST_STATE_GET_NEXT (current, pending);
2184 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2186 GST_STATE_NEXT (element) = next;
2188 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2189 GST_OBJECT_UNLOCK (element);
2191 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2192 "committing state from %s to %s, pending %s, next %s",
2193 gst_element_state_get_name (old_state),
2194 gst_element_state_get_name (old_next),
2195 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2197 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2198 old_state, old_next, pending);
2199 gst_element_post_message (element, message);
2201 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2202 "continue state change %s to %s, final %s",
2203 gst_element_state_get_name (current),
2204 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2206 ret = gst_element_change_state (element, transition);
2212 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2213 GST_OBJECT_UNLOCK (element);
2218 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2219 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2221 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2222 "completed state change to %s", gst_element_state_get_name (pending));
2223 GST_OBJECT_UNLOCK (element);
2225 /* don't post silly messages with the same state. This can happen
2226 * when an element state is changed to what it already was. For bins
2227 * this can be the result of a lost state, which we check with the
2228 * previous return value.
2229 * We do signal the cond though as a _get_state() might be blocking
2231 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2232 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2233 "posting state-changed %s to %s",
2234 gst_element_state_get_name (old_state),
2235 gst_element_state_get_name (old_next));
2237 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2238 old_next, GST_STATE_VOID_PENDING);
2239 gst_element_post_message (element, message);
2242 GST_STATE_BROADCAST (element);
2249 * gst_element_lost_state_full:
2250 * @element: a #GstElement the state is lost of
2251 * @new_base_time: if a new base time should be distributed
2253 * Brings the element to the lost state. The current state of the
2254 * element is copied to the pending state so that any call to
2255 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2257 * An ASYNC_START message is posted with indication to distribute a new
2258 * base_time to the element when @new_base_time is %TRUE.
2259 * If the element was PLAYING, it will go to PAUSED. The element
2260 * will be restored to its PLAYING state by the parent pipeline when it
2263 * This is mostly used for elements that lost their preroll buffer
2264 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2265 * they will go to their pending state again when a new preroll buffer is
2266 * queued. This function can only be called when the element is currently
2267 * not in error or an async state change.
2269 * This function is used internally and should normally not be called from
2270 * plugins or applications.
2277 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2279 GstState old_state, new_state;
2280 GstMessage *message;
2282 g_return_if_fail (GST_IS_ELEMENT (element));
2284 GST_OBJECT_LOCK (element);
2285 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2288 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2289 goto only_async_start;
2291 old_state = GST_STATE (element);
2293 /* when we were PLAYING, the new state is PAUSED. We will also not
2294 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2295 * when we preroll. */
2296 if (old_state > GST_STATE_PAUSED)
2297 new_state = GST_STATE_PAUSED;
2299 new_state = old_state;
2301 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2302 "lost state of %s to %s", gst_element_state_get_name (old_state),
2303 gst_element_state_get_name (new_state));
2305 GST_STATE (element) = new_state;
2306 GST_STATE_NEXT (element) = new_state;
2307 GST_STATE_PENDING (element) = new_state;
2308 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2310 GST_ELEMENT_START_TIME (element) = 0;
2311 GST_OBJECT_UNLOCK (element);
2313 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2314 new_state, new_state, new_state);
2315 gst_element_post_message (element, message);
2318 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2319 gst_element_post_message (element, message);
2325 GST_OBJECT_UNLOCK (element);
2330 GST_OBJECT_UNLOCK (element);
2332 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2333 gst_element_post_message (element, message);
2339 * gst_element_lost_state:
2340 * @element: a #GstElement the state is lost of
2342 * Brings the element to the lost state. This function calls
2343 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2345 * This function is used internally and should normally not be called from
2346 * plugins or applications.
2351 gst_element_lost_state (GstElement * element)
2353 gst_element_lost_state_full (element, TRUE);
2357 * gst_element_set_state:
2358 * @element: a #GstElement to change state of.
2359 * @state: the element's new #GstState.
2361 * Sets the state of the element. This function will try to set the
2362 * requested state by going through all the intermediary states and calling
2363 * the class's state change function for each.
2365 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2366 * element will perform the remainder of the state change asynchronously in
2368 * An application can use gst_element_get_state() to wait for the completion
2369 * of the state change or it can wait for a state change message on the bus.
2371 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2372 * #GST_STATE_CHANGE_ASYNC.
2374 * Returns: Result of the state change using #GstStateChangeReturn.
2378 GstStateChangeReturn
2379 gst_element_set_state (GstElement * element, GstState state)
2381 GstElementClass *oclass;
2382 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2384 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2386 oclass = GST_ELEMENT_GET_CLASS (element);
2388 if (oclass->set_state)
2389 result = (oclass->set_state) (element, state);
2395 * default set state function, calculates the next state based
2396 * on current state and calls the change_state function
2398 static GstStateChangeReturn
2399 gst_element_set_state_func (GstElement * element, GstState state)
2401 GstState current, next, old_pending;
2402 GstStateChangeReturn ret;
2403 GstStateChange transition;
2404 GstStateChangeReturn old_ret;
2406 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2408 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2409 gst_element_state_get_name (state));
2411 /* state lock is taken to protect the set_state() and get_state()
2412 * procedures, it does not lock any variables. */
2413 GST_STATE_LOCK (element);
2415 /* now calculate how to get to the new state */
2416 GST_OBJECT_LOCK (element);
2417 old_ret = GST_STATE_RETURN (element);
2418 /* previous state change returned an error, remove all pending
2419 * and next states */
2420 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2421 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2422 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2423 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2426 current = GST_STATE (element);
2427 next = GST_STATE_NEXT (element);
2428 old_pending = GST_STATE_PENDING (element);
2430 /* this is the (new) state we should go to. TARGET is the last state we set on
2432 if (state != GST_STATE_TARGET (element)) {
2433 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2434 "setting target state to %s", gst_element_state_get_name (state));
2435 GST_STATE_TARGET (element) = state;
2436 /* increment state cookie so that we can track each state change. We only do
2437 * this if this is actually a new state change. */
2438 element->state_cookie++;
2440 GST_STATE_PENDING (element) = state;
2442 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2443 "current %s, old_pending %s, next %s, old return %s",
2444 gst_element_state_get_name (current),
2445 gst_element_state_get_name (old_pending),
2446 gst_element_state_get_name (next),
2447 gst_element_state_change_return_get_name (old_ret));
2449 /* if the element was busy doing a state change, we just update the
2450 * target state, it'll get to it async then. */
2451 if (old_pending != GST_STATE_VOID_PENDING) {
2452 /* upwards state change will happen ASYNC */
2453 if (old_pending <= state)
2455 /* element is going to this state already */
2456 else if (next == state)
2458 /* element was performing an ASYNC upward state change and
2459 * we request to go downward again. Start from the next pending
2461 else if (next > state
2462 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2466 next = GST_STATE_GET_NEXT (current, state);
2467 /* now we store the next state */
2468 GST_STATE_NEXT (element) = next;
2469 /* mark busy, we need to check that there is actually a state change
2470 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2471 * the default element change_state function has no way to know what the
2472 * old value was... could consider this a FIXME...*/
2473 if (current != next)
2474 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2476 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2478 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2479 "%s: setting state from %s to %s",
2480 (next != state ? "intermediate" : "final"),
2481 gst_element_state_get_name (current), gst_element_state_get_name (next));
2483 /* now signal any waiters, they will error since the cookie was incremented */
2484 GST_STATE_BROADCAST (element);
2486 GST_OBJECT_UNLOCK (element);
2488 ret = gst_element_change_state (element, transition);
2490 GST_STATE_UNLOCK (element);
2492 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2493 gst_element_state_change_return_get_name (ret));
2499 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2500 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2501 "element was busy with async state change");
2502 GST_OBJECT_UNLOCK (element);
2504 GST_STATE_UNLOCK (element);
2506 return GST_STATE_CHANGE_ASYNC;
2511 * gst_element_change_state:
2512 * @element: a #GstElement
2513 * @transition: the requested transition
2515 * Perform @transition on @element.
2517 * This function must be called with STATE_LOCK held and is mainly used
2520 * Returns: the #GstStateChangeReturn of the state transition.
2522 GstStateChangeReturn
2523 gst_element_change_state (GstElement * element, GstStateChange transition)
2525 GstElementClass *oclass;
2526 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2528 oclass = GST_ELEMENT_GET_CLASS (element);
2530 /* call the state change function so it can set the state */
2531 if (oclass->change_state)
2532 ret = (oclass->change_state) (element, transition);
2534 ret = GST_STATE_CHANGE_FAILURE;
2537 case GST_STATE_CHANGE_FAILURE:
2538 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2539 "have FAILURE change_state return");
2540 /* state change failure */
2541 gst_element_abort_state (element);
2543 case GST_STATE_CHANGE_ASYNC:
2547 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2548 "element will change state ASYNC");
2550 target = GST_STATE_TARGET (element);
2552 if (target > GST_STATE_READY)
2555 /* else we just continue the state change downwards */
2556 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2557 "forcing commit state %s <= %s",
2558 gst_element_state_get_name (target),
2559 gst_element_state_get_name (GST_STATE_READY));
2561 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2564 case GST_STATE_CHANGE_SUCCESS:
2565 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2566 "element changed state SUCCESS");
2567 /* we can commit the state now which will proceeed to
2569 ret = gst_element_continue_state (element, ret);
2571 case GST_STATE_CHANGE_NO_PREROLL:
2572 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2573 "element changed state NO_PREROLL");
2574 /* we can commit the state now which will proceeed to
2576 ret = gst_element_continue_state (element, ret);
2579 goto invalid_return;
2582 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2587 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2595 GST_OBJECT_LOCK (element);
2596 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2597 g_critical ("%s: unknown return value %d from a state change function",
2598 GST_ELEMENT_NAME (element), ret);
2600 /* we are in error now */
2601 ret = GST_STATE_CHANGE_FAILURE;
2602 GST_STATE_RETURN (element) = ret;
2603 GST_OBJECT_UNLOCK (element);
2609 /* gst_iterator_fold functions for pads_activate
2610 * Note how we don't stop the iterator when we fail an activation. This is
2611 * probably a FIXME since when one pad activation fails, we don't want to
2612 * continue our state change. */
2614 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2616 if (!gst_pad_set_active (pad, *active))
2617 g_value_set_boolean (ret, FALSE);
2619 /* unref the object that was reffed for us by _fold */
2620 gst_object_unref (pad);
2624 /* set the caps on the pad to NULL */
2626 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2628 gst_pad_set_caps (pad, NULL);
2629 gst_object_unref (pad);
2633 /* returns false on error or early cutout (will never happen because the fold
2634 * function always returns TRUE, see FIXME above) of the fold, true if all
2635 * pads in @iter were (de)activated successfully. */
2637 iterator_activate_fold_with_resync (GstIterator * iter,
2638 GstIteratorFoldFunction func, gpointer user_data)
2640 GstIteratorResult ires;
2643 /* no need to unset this later, it's just a boolean */
2644 g_value_init (&ret, G_TYPE_BOOLEAN);
2645 g_value_set_boolean (&ret, TRUE);
2648 ires = gst_iterator_fold (iter, func, &ret, user_data);
2650 case GST_ITERATOR_RESYNC:
2651 /* need to reset the result again */
2652 g_value_set_boolean (&ret, TRUE);
2653 gst_iterator_resync (iter);
2655 case GST_ITERATOR_DONE:
2656 /* all pads iterated, return collected value */
2659 /* iterator returned _ERROR or premature end with _OK,
2660 * mark an error and exit */
2661 g_value_set_boolean (&ret, FALSE);
2666 /* return collected value */
2667 return g_value_get_boolean (&ret);
2670 /* is called with STATE_LOCK
2672 * Pads are activated from source pads to sinkpads.
2675 gst_element_pads_activate (GstElement * element, gboolean active)
2680 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2681 "pads_activate with active %d", active);
2683 iter = gst_element_iterate_src_pads (element);
2685 iterator_activate_fold_with_resync (iter,
2686 (GstIteratorFoldFunction) activate_pads, &active);
2687 gst_iterator_free (iter);
2688 if (G_UNLIKELY (!res))
2691 iter = gst_element_iterate_sink_pads (element);
2693 iterator_activate_fold_with_resync (iter,
2694 (GstIteratorFoldFunction) activate_pads, &active);
2695 gst_iterator_free (iter);
2696 if (G_UNLIKELY (!res))
2700 /* clear the caps on all pads, this should never fail */
2701 iter = gst_element_iterate_pads (element);
2703 iterator_activate_fold_with_resync (iter,
2704 (GstIteratorFoldFunction) clear_caps, &active);
2705 gst_iterator_free (iter);
2706 if (G_UNLIKELY (!res))
2710 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2711 "pads_activate successful");
2718 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2719 "source pads_activate failed");
2724 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2725 "sink pads_activate failed");
2730 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2731 "failed to clear caps on pads");
2736 /* is called with STATE_LOCK */
2737 static GstStateChangeReturn
2738 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2740 GstState state, next;
2741 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2744 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2746 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2747 next = GST_STATE_TRANSITION_NEXT (transition);
2749 /* if the element already is in the given state, we just return success */
2750 if (next == GST_STATE_VOID_PENDING || state == next)
2753 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2754 "default handler tries setting state from %s to %s (%04x)",
2755 gst_element_state_get_name (state),
2756 gst_element_state_get_name (next), transition);
2758 switch (transition) {
2759 case GST_STATE_CHANGE_NULL_TO_READY:
2761 case GST_STATE_CHANGE_READY_TO_PAUSED:
2762 if (!gst_element_pads_activate (element, TRUE)) {
2763 result = GST_STATE_CHANGE_FAILURE;
2766 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2768 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2770 case GST_STATE_CHANGE_PAUSED_TO_READY:
2771 case GST_STATE_CHANGE_READY_TO_NULL:
2772 /* deactivate pads in both cases, since they are activated on
2773 ready->paused but the element might not have made it to paused */
2774 if (!gst_element_pads_activate (element, FALSE)) {
2775 result = GST_STATE_CHANGE_FAILURE;
2777 gst_element_set_base_time (element, 0);
2780 /* In null state release the reference to the clock */
2781 GST_OBJECT_LOCK (element);
2782 clock_p = &element->clock;
2783 gst_object_replace ((GstObject **) clock_p, NULL);
2784 GST_OBJECT_UNLOCK (element);
2787 /* this will catch real but unhandled state changes;
2788 * can only be caused by:
2789 * - a new state was added
2790 * - somehow the element was asked to jump across an intermediate state
2792 g_warning ("Unhandled state change from %s to %s",
2793 gst_element_state_get_name (state),
2794 gst_element_state_get_name (next));
2801 GST_OBJECT_LOCK (element);
2802 result = GST_STATE_RETURN (element);
2803 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2804 "element is already in the %s state",
2805 gst_element_state_get_name (state));
2806 GST_OBJECT_UNLOCK (element);
2813 * gst_element_get_factory:
2814 * @element: a #GstElement to request the element factory of.
2816 * Retrieves the factory that was used to create this element.
2818 * Returns: the #GstElementFactory used for creating this element.
2819 * no refcounting is needed.
2822 gst_element_get_factory (GstElement * element)
2824 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2826 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2830 gst_element_dispose (GObject * object)
2832 GstElement *element = GST_ELEMENT_CAST (object);
2836 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2838 if (GST_STATE (element) != GST_STATE_NULL)
2841 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2842 "removing %d pads", g_list_length (element->pads));
2843 /* first we break all our links with the outside */
2844 while (element->pads && element->pads->data) {
2845 /* don't call _remove_pad with NULL */
2846 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2848 if (G_UNLIKELY (element->pads != NULL)) {
2849 g_critical ("could not remove pads from element %s",
2850 GST_STR_NULL (GST_OBJECT_NAME (object)));
2853 GST_OBJECT_LOCK (element);
2854 clock_p = &element->clock;
2855 bus_p = &element->bus;
2856 gst_object_replace ((GstObject **) clock_p, NULL);
2857 gst_object_replace ((GstObject **) bus_p, NULL);
2858 GST_OBJECT_UNLOCK (element);
2860 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2862 G_OBJECT_CLASS (parent_class)->dispose (object);
2871 is_locked = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
2873 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2875 "You need to explicitly set elements to the NULL state before\n"
2876 "dropping the final reference, to allow them to clean up.\n"
2877 "This problem may also be caused by a refcounting bug in the\n"
2878 "application or some element.\n",
2879 GST_OBJECT_NAME (element),
2880 gst_element_state_get_name (GST_STATE (element)),
2881 is_locked ? " (locked)" : "");
2887 gst_element_finalize (GObject * object)
2889 GstElement *element = GST_ELEMENT_CAST (object);
2891 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2893 GST_STATE_LOCK (element);
2894 if (element->state_cond)
2895 g_cond_free (element->state_cond);
2896 element->state_cond = NULL;
2897 GST_STATE_UNLOCK (element);
2898 g_static_rec_mutex_free (element->state_lock);
2899 g_slice_free (GStaticRecMutex, element->state_lock);
2900 element->state_lock = NULL;
2902 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2904 G_OBJECT_CLASS (parent_class)->finalize (object);
2907 #ifndef GST_DISABLE_LOADSAVE
2909 * gst_element_save_thyself:
2910 * @element: a #GstElement to save.
2911 * @parent: the xml parent node.
2913 * Saves the element as part of the given XML structure.
2915 * Returns: the new #xmlNodePtr.
2918 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2921 GstElementClass *oclass;
2922 GParamSpec **specs, *spec;
2925 GValue value = { 0, };
2926 GstElement *element;
2928 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2930 element = GST_ELEMENT_CAST (object);
2932 oclass = GST_ELEMENT_GET_CLASS (element);
2934 xmlNewChild (parent, NULL, (xmlChar *) "name",
2935 (xmlChar *) GST_ELEMENT_NAME (element));
2937 if (oclass->elementfactory != NULL) {
2938 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2940 xmlNewChild (parent, NULL, (xmlChar *) "type",
2941 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2945 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2947 for (i = 0; i < nspecs; i++) {
2949 if (spec->flags & G_PARAM_READABLE) {
2953 g_value_init (&value, spec->value_type);
2955 g_object_get_property (G_OBJECT (element), spec->name, &value);
2956 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2957 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2959 if (G_IS_PARAM_SPEC_STRING (spec))
2960 contents = g_value_dup_string (&value);
2961 else if (G_IS_PARAM_SPEC_ENUM (spec))
2962 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2963 else if (G_IS_PARAM_SPEC_INT64 (spec))
2964 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2965 g_value_get_int64 (&value));
2966 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
2967 if (g_value_get_boxed (&value) != NULL) {
2968 contents = g_strdup_value_contents (&value);
2970 contents = g_strdup ("NULL");
2973 contents = g_strdup_value_contents (&value);
2975 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2978 g_value_unset (&value);
2984 pads = g_list_last (GST_ELEMENT_PADS (element));
2987 GstPad *pad = GST_PAD_CAST (pads->data);
2989 /* figure out if it's a direct pad or a ghostpad */
2990 if (GST_ELEMENT_CAST (GST_OBJECT_PARENT (pad)) == element) {
2991 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
2993 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
2995 pads = g_list_previous (pads);
3002 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3004 xmlNodePtr children;
3005 GstElement *element;
3007 gchar *value = NULL;
3009 element = GST_ELEMENT_CAST (object);
3010 g_return_if_fail (element != NULL);
3013 children = self->xmlChildrenNode;
3015 if (!strcmp ((char *) children->name, "param")) {
3016 xmlNodePtr child = children->xmlChildrenNode;
3019 if (!strcmp ((char *) child->name, "name")) {
3020 name = (gchar *) xmlNodeGetContent (child);
3021 } else if (!strcmp ((char *) child->name, "value")) {
3022 value = (gchar *) xmlNodeGetContent (child);
3024 child = child->next;
3026 /* FIXME: can this just be g_object_set ? */
3027 gst_util_set_object_arg (G_OBJECT (element), name, value);
3028 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3032 children = children->next;
3036 children = self->xmlChildrenNode;
3038 if (!strcmp ((char *) children->name, "pad")) {
3039 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3041 children = children->next;
3044 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3045 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3047 #endif /* GST_DISABLE_LOADSAVE */
3050 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3054 g_return_if_fail (GST_IS_ELEMENT (element));
3056 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3058 GST_OBJECT_LOCK (element);
3059 bus_p = &GST_ELEMENT_BUS (element);
3060 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3061 GST_OBJECT_UNLOCK (element);
3065 * gst_element_set_bus:
3066 * @element: a #GstElement to set the bus of.
3067 * @bus: the #GstBus to set.
3069 * Sets the bus of the element. Increases the refcount on the bus.
3070 * For internal use only, unless you're testing elements.
3075 gst_element_set_bus (GstElement * element, GstBus * bus)
3077 GstElementClass *oclass;
3079 g_return_if_fail (GST_IS_ELEMENT (element));
3081 oclass = GST_ELEMENT_GET_CLASS (element);
3083 if (oclass->set_bus)
3084 oclass->set_bus (element, bus);
3088 * gst_element_get_bus:
3089 * @element: a #GstElement to get the bus of.
3091 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3092 * bus for the application.
3094 * Returns: the element's #GstBus. unref after usage.
3099 gst_element_get_bus (GstElement * element)
3101 GstBus *result = NULL;
3103 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3105 GST_OBJECT_LOCK (element);
3106 if ((result = GST_ELEMENT_BUS (element)))
3107 gst_object_ref (result);
3108 GST_OBJECT_UNLOCK (element);
3110 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,