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 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate or
47 * gst_element_get_request_pad() with the template name such as "src_\%d".
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * gst_element_provides_clock() returns %TRUE. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If
72 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock slection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
79 * Last reviewed on 2009-05-29 (0.10.24)
82 #include "gst_private.h"
85 #include <gobject/gvaluecollector.h>
87 #include "gstelement.h"
88 #include "gstelementmetadata.h"
89 #include "gstenumtypes.h"
91 #include "gstmarshal.h"
97 #include "gst-i18n-lib.h"
99 /* Element signals and args */
115 static void gst_element_class_init (GstElementClass * klass);
116 static void gst_element_init (GstElement * element);
117 static void gst_element_base_class_init (gpointer g_class);
118 static void gst_element_base_class_finalize (gpointer g_class);
120 static void gst_element_dispose (GObject * object);
121 static void gst_element_finalize (GObject * object);
123 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
124 GstStateChange transition);
125 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
126 GstState * state, GstState * pending, GstClockTime timeout);
127 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
129 static gboolean gst_element_set_clock_func (GstElement * element,
131 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
133 static gboolean gst_element_default_send_event (GstElement * element,
135 static gboolean gst_element_default_query (GstElement * element,
138 static GstPadTemplate
139 * gst_element_class_get_request_pad_template (GstElementClass *
140 element_class, const gchar * name);
142 static GstObjectClass *parent_class = NULL;
143 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
145 /* this is used in gstelementfactory.c:gst_element_register() */
146 GQuark __gst_elementclass_factory = 0;
149 gst_element_get_type (void)
151 static volatile gsize gst_element_type = 0;
153 if (g_once_init_enter (&gst_element_type)) {
155 static const GTypeInfo element_info = {
156 sizeof (GstElementClass),
157 gst_element_base_class_init,
158 gst_element_base_class_finalize,
159 (GClassInitFunc) gst_element_class_init,
164 (GInstanceInitFunc) gst_element_init,
168 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
169 &element_info, G_TYPE_FLAG_ABSTRACT);
171 __gst_elementclass_factory =
172 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
173 g_once_init_leave (&gst_element_type, _type);
175 return gst_element_type;
179 gst_element_class_init (GstElementClass * klass)
181 GObjectClass *gobject_class;
183 gobject_class = (GObjectClass *) klass;
185 parent_class = g_type_class_peek_parent (klass);
188 * GstElement::pad-added:
189 * @gstelement: the object which received the signal
190 * @new_pad: the pad that has been added
192 * a new #GstPad has been added to the element. Note that this signal will
193 * usually be emitted from the context of the streaming thread. Also keep in
194 * mind that if you add new elements to the pipeline in the signal handler
195 * you will need to set them to the desired target state with
196 * gst_element_set_state() or gst_element_sync_state_with_parent().
198 gst_element_signals[PAD_ADDED] =
199 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
200 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
201 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
203 * GstElement::pad-removed:
204 * @gstelement: the object which received the signal
205 * @old_pad: the pad that has been removed
207 * a #GstPad has been removed from the element
209 gst_element_signals[PAD_REMOVED] =
210 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
211 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
212 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
214 * GstElement::no-more-pads:
215 * @gstelement: the object which received the signal
217 * This signals that the element will not generate more dynamic pads.
218 * Note that this signal will usually be emitted from the context of
219 * the streaming thread.
221 gst_element_signals[NO_MORE_PADS] =
222 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
223 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
224 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
226 gobject_class->dispose = gst_element_dispose;
227 gobject_class->finalize = gst_element_finalize;
229 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
230 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
231 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
232 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
233 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
234 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
235 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
236 klass->numpadtemplates = 0;
238 klass->elementfactory = NULL;
242 gst_element_base_class_init (gpointer g_class)
244 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
245 GList *node, *padtemplates;
247 /* Copy the element details here so elements can inherit the
248 * details from their base class and classes only need to set
249 * the details in class_init instead of base_init */
250 element_class->metadata =
251 element_class->metadata ? gst_structure_copy (element_class->metadata) :
252 gst_structure_new_empty ("metadata");
254 /* Copy the pad templates so elements inherit them
255 * from their base class but elements can add pad templates in class_init
256 * instead of base_init.
258 padtemplates = g_list_copy (element_class->padtemplates);
259 for (node = padtemplates; node != NULL; node = node->next) {
260 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
261 gst_object_ref (tmpl);
263 element_class->padtemplates = padtemplates;
265 /* set the factory, see gst_element_register() */
266 element_class->elementfactory =
267 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
268 __gst_elementclass_factory);
269 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
270 element_class->elementfactory);
274 gst_element_base_class_finalize (gpointer g_class)
276 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
278 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
279 g_list_free (klass->padtemplates);
281 gst_structure_free (klass->metadata);
285 gst_element_init (GstElement * element)
287 GST_STATE (element) = GST_STATE_NULL;
288 GST_STATE_TARGET (element) = GST_STATE_NULL;
289 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
290 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
291 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
293 g_static_rec_mutex_init (&element->state_lock);
294 element->state_cond = g_cond_new ();
298 * gst_element_release_request_pad:
299 * @element: a #GstElement to release the request pad of.
300 * @pad: the #GstPad to release.
302 * Makes the element free the previously requested pad as obtained
303 * with gst_element_get_request_pad().
305 * This does not unref the pad. If the pad was created by using
306 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
307 * followed by gst_object_unref() to free the @pad.
312 gst_element_release_request_pad (GstElement * element, GstPad * pad)
314 GstElementClass *oclass;
316 g_return_if_fail (GST_IS_ELEMENT (element));
317 g_return_if_fail (GST_IS_PAD (pad));
319 oclass = GST_ELEMENT_GET_CLASS (element);
321 /* if the element implements a custom release function we call that, else we
322 * simply remove the pad from the element */
323 if (oclass->release_pad)
324 (oclass->release_pad) (element, pad);
326 gst_element_remove_pad (element, pad);
330 * gst_element_provide_clock:
331 * @element: a #GstElement to query
333 * Get the clock provided by the given element.
334 * <note>An element is only required to provide a clock in the PAUSED
335 * state. Some elements can provide a clock in other states.</note>
337 * Returns: (transfer full): the GstClock provided by the element or %NULL
338 * if no clock could be provided. Unref after usage.
343 gst_element_provide_clock (GstElement * element)
345 GstClock *result = NULL;
346 GstElementClass *oclass;
348 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
350 oclass = GST_ELEMENT_GET_CLASS (element);
352 if (oclass->provide_clock)
353 result = oclass->provide_clock (element);
359 gst_element_set_clock_func (GstElement * element, GstClock * clock)
363 GST_OBJECT_LOCK (element);
364 clock_p = &element->clock;
365 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
366 GST_OBJECT_UNLOCK (element);
372 * gst_element_set_clock:
373 * @element: a #GstElement to set the clock for.
374 * @clock: the #GstClock to set for the element.
376 * Sets the clock for the element. This function increases the
377 * refcount on the clock. Any previously set clock on the object
380 * Returns: %TRUE if the element accepted the clock. An element can refuse a
381 * clock when it, for example, is not able to slave its internal clock to the
382 * @clock or when it requires a specific clock to operate.
387 gst_element_set_clock (GstElement * element, GstClock * clock)
389 GstElementClass *oclass;
390 gboolean res = FALSE;
392 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
393 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
395 oclass = GST_ELEMENT_GET_CLASS (element);
397 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
399 if (oclass->set_clock)
400 res = oclass->set_clock (element, clock);
406 * gst_element_get_clock:
407 * @element: a #GstElement to get the clock of.
409 * Gets the currently configured clock of the element. This is the clock as was
410 * last set with gst_element_set_clock().
412 * Returns: (transfer full): the #GstClock of the element. unref after usage.
417 gst_element_get_clock (GstElement * element)
421 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
423 GST_OBJECT_LOCK (element);
424 if ((result = element->clock))
425 gst_object_ref (result);
426 GST_OBJECT_UNLOCK (element);
432 * gst_element_set_base_time:
433 * @element: a #GstElement.
434 * @time: the base time to set.
436 * Set the base time of an element. See gst_element_get_base_time().
441 gst_element_set_base_time (GstElement * element, GstClockTime time)
445 g_return_if_fail (GST_IS_ELEMENT (element));
447 GST_OBJECT_LOCK (element);
448 old = element->base_time;
449 element->base_time = time;
450 GST_OBJECT_UNLOCK (element);
452 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
453 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
454 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
458 * gst_element_get_base_time:
459 * @element: a #GstElement.
461 * Returns the base time of the element. The base time is the
462 * absolute time of the clock when this element was last put to
463 * PLAYING. Subtracting the base time from the clock time gives
464 * the running time of the element.
466 * Returns: the base time of the element.
471 gst_element_get_base_time (GstElement * element)
475 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
477 GST_OBJECT_LOCK (element);
478 result = element->base_time;
479 GST_OBJECT_UNLOCK (element);
485 * gst_element_set_start_time:
486 * @element: a #GstElement.
487 * @time: the base time to set.
489 * Set the start time of an element. The start time of the element is the
490 * running time of the element when it last went to the PAUSED state. In READY
491 * or after a flushing seek, it is set to 0.
493 * Toplevel elements like #GstPipeline will manage the start_time and
494 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
495 * on such a toplevel element will disable the distribution of the base_time to
496 * the children and can be useful if the application manages the base_time
497 * itself, for example if you want to synchronize capture from multiple
498 * pipelines, and you can also ensure that the pipelines have the same clock.
505 gst_element_set_start_time (GstElement * element, GstClockTime time)
509 g_return_if_fail (GST_IS_ELEMENT (element));
511 GST_OBJECT_LOCK (element);
512 old = GST_ELEMENT_START_TIME (element);
513 GST_ELEMENT_START_TIME (element) = time;
514 GST_OBJECT_UNLOCK (element);
516 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
517 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
518 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
522 * gst_element_get_start_time:
523 * @element: a #GstElement.
525 * Returns the start time of the element. The start time is the
526 * running time of the clock when this element was last put to PAUSED.
528 * Usually the start_time is managed by a toplevel element such as
533 * Returns: the start time of the element.
538 gst_element_get_start_time (GstElement * element)
542 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
544 GST_OBJECT_LOCK (element);
545 result = GST_ELEMENT_START_TIME (element);
546 GST_OBJECT_UNLOCK (element);
552 * gst_element_set_index:
553 * @element: a #GstElement.
554 * @index: (transfer none): a #GstIndex.
556 * Set @index on the element. The refcount of the index
557 * will be increased, any previously set index is unreffed.
562 gst_element_set_index (GstElement * element, GstIndex * index)
564 GstElementClass *oclass;
566 g_return_if_fail (GST_IS_ELEMENT (element));
567 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
569 oclass = GST_ELEMENT_GET_CLASS (element);
571 if (oclass->set_index)
572 oclass->set_index (element, index);
576 * gst_element_get_index:
577 * @element: a #GstElement.
579 * Gets the index from the element.
581 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
582 * element. unref after usage.
587 gst_element_get_index (GstElement * element)
589 GstElementClass *oclass;
590 GstIndex *result = NULL;
592 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
594 oclass = GST_ELEMENT_GET_CLASS (element);
596 if (oclass->get_index)
597 result = oclass->get_index (element);
603 * gst_element_add_pad:
604 * @element: a #GstElement to add the pad to.
605 * @pad: (transfer full): the #GstPad to add to the element.
607 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
608 * see gst_object_set_parent() for refcounting information.
610 * Pads are not automatically activated so elements should perform the needed
611 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
612 * state. See gst_pad_set_active() for more information about activating pads.
614 * The pad and the element should be unlocked when calling this function.
616 * This function will emit the #GstElement::pad-added signal on the element.
618 * Returns: %TRUE if the pad could be added. This function can fail when
619 * a pad with the same name already existed or the pad already had another
625 gst_element_add_pad (GstElement * element, GstPad * pad)
630 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
631 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
633 /* locking pad to look at the name */
634 GST_OBJECT_LOCK (pad);
635 pad_name = g_strdup (GST_PAD_NAME (pad));
636 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
637 GST_STR_NULL (pad_name));
638 flushing = GST_PAD_IS_FLUSHING (pad);
639 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
640 GST_OBJECT_UNLOCK (pad);
642 /* then check to see if there's already a pad by that name here */
643 GST_OBJECT_LOCK (element);
644 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
647 /* try to set the pad's parent */
648 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
649 GST_OBJECT_CAST (element))))
652 /* check for flushing pads */
653 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
654 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
655 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
656 "use gst_pad_set_active(pad,TRUE) before adding it.",
657 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
659 GST_OBJECT_LOCK (pad);
660 GST_PAD_UNSET_FLUSHING (pad);
661 GST_OBJECT_UNLOCK (pad);
666 /* add it to the list */
667 switch (gst_pad_get_direction (pad)) {
669 element->srcpads = g_list_prepend (element->srcpads, pad);
670 element->numsrcpads++;
673 element->sinkpads = g_list_prepend (element->sinkpads, pad);
674 element->numsinkpads++;
679 element->pads = g_list_prepend (element->pads, pad);
681 element->pads_cookie++;
682 GST_OBJECT_UNLOCK (element);
684 /* emit the PAD_ADDED signal */
685 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
692 g_critical ("Padname %s is not unique in element %s, not adding",
693 pad_name, GST_ELEMENT_NAME (element));
694 GST_OBJECT_UNLOCK (element);
701 ("Pad %s already has parent when trying to add to element %s",
702 pad_name, GST_ELEMENT_NAME (element));
703 GST_OBJECT_UNLOCK (element);
709 GST_OBJECT_LOCK (pad);
711 ("Trying to add pad %s to element %s, but it has no direction",
712 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
713 GST_OBJECT_UNLOCK (pad);
714 GST_OBJECT_UNLOCK (element);
720 * gst_element_remove_pad:
721 * @element: a #GstElement to remove pad from.
722 * @pad: (transfer none): the #GstPad to remove from the element.
724 * Removes @pad from @element. @pad will be destroyed if it has not been
725 * referenced elsewhere using gst_object_unparent().
727 * This function is used by plugin developers and should not be used
728 * by applications. Pads that were dynamically requested from elements
729 * with gst_element_get_request_pad() should be released with the
730 * gst_element_release_request_pad() function instead.
732 * Pads are not automatically deactivated so elements should perform the needed
733 * steps to deactivate the pad in case this pad is removed in the PAUSED or
734 * PLAYING state. See gst_pad_set_active() for more information about
737 * The pad and the element should be unlocked when calling this function.
739 * This function will emit the #GstElement::pad-removed signal on the element.
741 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
742 * pad does not belong to the provided element.
747 gst_element_remove_pad (GstElement * element, GstPad * pad)
751 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
752 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
754 /* locking pad to look at the name and parent */
755 GST_OBJECT_LOCK (pad);
756 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
757 GST_STR_NULL (GST_PAD_NAME (pad)));
759 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
761 GST_OBJECT_UNLOCK (pad);
764 if ((peer = gst_pad_get_peer (pad))) {
765 /* window for MT unsafeness, someone else could unlink here
766 * and then we call unlink with wrong pads. The unlink
767 * function would catch this and safely return failed. */
768 if (GST_PAD_IS_SRC (pad))
769 gst_pad_unlink (pad, peer);
771 gst_pad_unlink (peer, pad);
773 gst_object_unref (peer);
776 GST_OBJECT_LOCK (element);
777 /* remove it from the list */
778 switch (gst_pad_get_direction (pad)) {
780 element->srcpads = g_list_remove (element->srcpads, pad);
781 element->numsrcpads--;
784 element->sinkpads = g_list_remove (element->sinkpads, pad);
785 element->numsinkpads--;
788 g_critical ("Removing pad without direction???");
791 element->pads = g_list_remove (element->pads, pad);
793 element->pads_cookie++;
794 GST_OBJECT_UNLOCK (element);
796 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
797 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
799 gst_object_unparent (GST_OBJECT_CAST (pad));
806 /* locking order is element > pad */
807 GST_OBJECT_UNLOCK (pad);
809 GST_OBJECT_LOCK (element);
810 GST_OBJECT_LOCK (pad);
811 g_critical ("Padname %s:%s does not belong to element %s when removing",
812 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
813 GST_OBJECT_UNLOCK (pad);
814 GST_OBJECT_UNLOCK (element);
820 * gst_element_no_more_pads:
821 * @element: a #GstElement
823 * Use this function to signal that the element does not expect any more pads
824 * to show up in the current pipeline. This function should be called whenever
825 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
826 * pad templates use this in combination with autopluggers to figure out that
827 * the element is done initializing its pads.
829 * This function emits the #GstElement::no-more-pads signal.
834 gst_element_no_more_pads (GstElement * element)
836 g_return_if_fail (GST_IS_ELEMENT (element));
838 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
842 pad_compare_name (GstPad * pad1, const gchar * name)
846 GST_OBJECT_LOCK (pad1);
847 result = strcmp (GST_PAD_NAME (pad1), name);
848 GST_OBJECT_UNLOCK (pad1);
854 * gst_element_get_static_pad:
855 * @element: a #GstElement to find a static pad of.
856 * @name: the name of the static #GstPad to retrieve.
858 * Retrieves a pad from @element by name. This version only retrieves
859 * already-existing (i.e. 'static') pads.
861 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
867 gst_element_get_static_pad (GstElement * element, const gchar * name)
870 GstPad *result = NULL;
872 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
873 g_return_val_if_fail (name != NULL, NULL);
875 GST_OBJECT_LOCK (element);
877 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
879 result = GST_PAD_CAST (find->data);
880 gst_object_ref (result);
883 if (result == NULL) {
884 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
885 name, GST_ELEMENT_NAME (element));
887 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
888 GST_ELEMENT_NAME (element), name);
890 GST_OBJECT_UNLOCK (element);
896 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
897 const gchar * name, const GstCaps * caps)
899 GstPad *newpad = NULL;
900 GstElementClass *oclass;
902 oclass = GST_ELEMENT_GET_CLASS (element);
904 #ifndef G_DISABLE_CHECKS
905 /* Some sanity checking here */
909 /* Is this the template name? */
910 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
911 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
913 const gchar *str, *data;
916 /* Otherwise check if it's a valid name for the name template */
917 str = strchr (templ->name_template, '%');
918 g_return_val_if_fail (str != NULL, NULL);
919 g_return_val_if_fail (strncmp (templ->name_template, name,
920 str - templ->name_template) == 0, NULL);
921 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
923 data = name + (str - templ->name_template);
925 /* Can either be %s or %d or %u, do sanity checking for %d */
926 if (*(str + 1) == 'd') {
930 tmp = g_ascii_strtoll (data, &endptr, 10);
931 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
932 && *endptr == '\0', NULL);
933 } else if (*(str + 1) == 'u') {
937 tmp = g_ascii_strtoull (data, &endptr, 10);
938 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
942 pad = gst_element_get_static_pad (element, name);
944 gst_object_unref (pad);
945 /* FIXME 0.11: Change this to g_return_val_if_fail() */
946 g_critical ("Element %s already has a pad named %s, the behaviour of "
947 " gst_element_get_request_pad() for existing pads is undefined!",
948 GST_ELEMENT_NAME (element), name);
953 if (oclass->request_new_pad)
954 newpad = (oclass->request_new_pad) (element, templ, name, caps);
957 gst_object_ref (newpad);
963 * gst_element_get_request_pad:
964 * @element: a #GstElement to find a request pad of.
965 * @name: the name of the request #GstPad to retrieve.
967 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
968 * retrieves request pads. The pad should be released with
969 * gst_element_release_request_pad().
971 * This method is slow and will be deprecated in the future. New code should
972 * use gst_element_request_pad() with the requested template.
974 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
975 * Release after usage.
978 gst_element_get_request_pad (GstElement * element, const gchar * name)
980 GstPadTemplate *templ = NULL;
982 const gchar *req_name = NULL;
983 gboolean templ_found = FALSE;
986 gchar *str, *endptr = NULL;
987 GstElementClass *class;
989 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
990 g_return_val_if_fail (name != NULL, NULL);
992 class = GST_ELEMENT_GET_CLASS (element);
994 /* if the name contains a %, we assume it's the complete template name. Get
995 * the template and try to get a pad */
996 if (strstr (name, "%")) {
997 templ = gst_element_class_get_request_pad_template (class, name);
1002 /* there is no % in the name, try to find a matching template */
1003 list = class->padtemplates;
1004 while (!templ_found && list) {
1005 templ = (GstPadTemplate *) list->data;
1006 if (templ->presence == GST_PAD_REQUEST) {
1007 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1008 templ->name_template);
1009 /* see if we find an exact match */
1010 if (strcmp (name, templ->name_template) == 0) {
1015 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1016 and %d and %u, occurring at the end of the name_template, are the only
1018 else if ((str = strchr (templ->name_template, '%'))
1019 && strncmp (templ->name_template, name,
1020 str - templ->name_template) == 0
1021 && strlen (name) > str - templ->name_template) {
1022 data = name + (str - templ->name_template);
1023 if (*(str + 1) == 'd') {
1027 tmp = strtol (data, &endptr, 10);
1028 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1034 } else if (*(str + 1) == 'u') {
1038 tmp = strtoul (data, &endptr, 10);
1039 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1059 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1065 * gst_element_request_pad:
1066 * @element: a #GstElement to find a request pad of.
1067 * @templ: a #GstPadTemplate of which we want a pad of.
1068 * @name: (transfer none) (allow-none): the name of the request #GstPad
1069 * to retrieve. Can be %NULL.
1070 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1071 * request. Can be %NULL.
1073 * Retrieves a request pad from the element according to the provided template.
1074 * Pad templates can be looked up using
1075 * gst_element_factory_get_static_pad_templates().
1077 * The pad should be released with gst_element_release_request_pad().
1079 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1080 * Release after usage.
1085 gst_element_request_pad (GstElement * element,
1086 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1088 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1089 g_return_val_if_fail (templ != NULL, NULL);
1091 return _gst_element_request_pad (element, templ, name, caps);
1094 static GstIterator *
1095 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1097 GstIterator *result;
1099 GST_OBJECT_LOCK (element);
1100 result = gst_iterator_new_list (GST_TYPE_PAD,
1101 GST_OBJECT_GET_LOCK (element),
1102 &element->pads_cookie, padlist, (GObject *) element, NULL);
1103 GST_OBJECT_UNLOCK (element);
1109 * gst_element_iterate_pads:
1110 * @element: a #GstElement to iterate pads of.
1112 * Retrieves an iterator of @element's pads. The iterator should
1113 * be freed after usage. Also more specialized iterators exists such as
1114 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1116 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1122 gst_element_iterate_pads (GstElement * element)
1124 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1126 return gst_element_iterate_pad_list (element, &element->pads);
1130 * gst_element_iterate_src_pads:
1131 * @element: a #GstElement.
1133 * Retrieves an iterator of @element's source pads.
1135 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1141 gst_element_iterate_src_pads (GstElement * element)
1143 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1145 return gst_element_iterate_pad_list (element, &element->srcpads);
1149 * gst_element_iterate_sink_pads:
1150 * @element: a #GstElement.
1152 * Retrieves an iterator of @element's sink pads.
1154 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1160 gst_element_iterate_sink_pads (GstElement * element)
1162 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1164 return gst_element_iterate_pad_list (element, &element->sinkpads);
1168 * gst_element_class_add_pad_template:
1169 * @klass: the #GstElementClass to add the pad template to.
1170 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1172 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1173 * functions of classes. If a pad template with the same name as an already
1174 * existing one is added the old one is replaced by the new one.
1178 gst_element_class_add_pad_template (GstElementClass * klass,
1179 GstPadTemplate * templ)
1181 GList *template_list = klass->padtemplates;
1183 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1184 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1186 /* If we already have a pad template with the same name replace the
1188 while (template_list) {
1189 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1191 /* Found pad with the same name, replace and return */
1192 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1193 gst_object_unref (padtempl);
1194 template_list->data = templ;
1197 template_list = g_list_next (template_list);
1200 /* Take ownership of the floating ref */
1201 gst_object_ref_sink (templ);
1203 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1204 klass->numpadtemplates++;
1208 * gst_element_class_add_metadata:
1209 * @klass: class to set metadata for
1210 * @key: the key to set
1211 * @value: the value to set
1213 * Set @key with @value as metadata in @klass.
1216 gst_element_class_add_metadata (GstElementClass * klass,
1217 const gchar * key, const gchar * value)
1219 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1220 g_return_if_fail (key != NULL);
1221 g_return_if_fail (value != NULL);
1223 gst_structure_set ((GstStructure *) klass->metadata,
1224 key, G_TYPE_STRING, value, NULL);
1228 * gst_element_class_set_metadata:
1229 * @klass: class to set metadata for
1230 * @longname: The long English name of the element. E.g. "File Sink"
1231 * @classification: String describing the type of element, as an unordered list
1232 * separated with slashes ('/'). See draft-klass.txt of the design docs
1233 * for more details and common types. E.g: "Sink/File"
1234 * @description: Sentence describing the purpose of the element.
1235 * E.g: "Write stream to a file"
1236 * @author: Name and contact details of the author(s). Use \n to separate
1237 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1239 * Sets the detailed information for a #GstElementClass.
1240 * <note>This function is for use in _class_init functions only.</note>
1243 gst_element_class_set_metadata (GstElementClass * klass,
1244 const gchar * longname, const gchar * classification,
1245 const gchar * description, const gchar * author)
1247 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1249 gst_structure_set ((GstStructure *) klass->metadata,
1250 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1251 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1252 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1253 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1257 * gst_element_class_get_metadata:
1258 * @klass: class to get metadata for
1259 * @key: the key to get
1261 * Get metadata with @key in @klass.
1263 * Returns: the metadata for @key.
1266 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1268 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1269 g_return_val_if_fail (key != NULL, NULL);
1271 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1275 * gst_element_class_get_pad_template_list:
1276 * @element_class: a #GstElementClass to get pad templates of.
1278 * Retrieves a list of the pad templates associated with @element_class. The
1279 * list must not be modified by the calling code.
1280 * <note>If you use this function in the #GInstanceInitFunc of an object class
1281 * that has subclasses, make sure to pass the g_class parameter of the
1282 * #GInstanceInitFunc here.</note>
1284 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1288 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1290 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1292 return element_class->padtemplates;
1296 * gst_element_class_get_pad_template:
1297 * @element_class: a #GstElementClass to get the pad template of.
1298 * @name: the name of the #GstPadTemplate to get.
1300 * Retrieves a padtemplate from @element_class with the given name.
1301 * <note>If you use this function in the #GInstanceInitFunc of an object class
1302 * that has subclasses, make sure to pass the g_class parameter of the
1303 * #GInstanceInitFunc here.</note>
1305 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1306 * if none was found. No unreferencing is necessary.
1309 gst_element_class_get_pad_template (GstElementClass *
1310 element_class, const gchar * name)
1314 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1315 g_return_val_if_fail (name != NULL, NULL);
1317 padlist = element_class->padtemplates;
1320 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1322 if (strcmp (padtempl->name_template, name) == 0)
1325 padlist = g_list_next (padlist);
1331 static GstPadTemplate *
1332 gst_element_class_get_request_pad_template (GstElementClass *
1333 element_class, const gchar * name)
1335 GstPadTemplate *tmpl;
1337 tmpl = gst_element_class_get_pad_template (element_class, name);
1338 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1344 /* get a random pad on element of the given direction.
1345 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1348 gst_element_get_random_pad (GstElement * element,
1349 gboolean need_linked, GstPadDirection dir)
1351 GstPad *result = NULL;
1354 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1358 GST_OBJECT_LOCK (element);
1359 pads = element->srcpads;
1362 GST_OBJECT_LOCK (element);
1363 pads = element->sinkpads;
1366 goto wrong_direction;
1368 for (; pads; pads = g_list_next (pads)) {
1369 GstPad *pad = GST_PAD_CAST (pads->data);
1371 GST_OBJECT_LOCK (pad);
1372 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1373 GST_DEBUG_PAD_NAME (pad));
1375 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1376 /* if we require a linked pad, and it is not linked, continue the
1378 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1379 GST_DEBUG_PAD_NAME (pad));
1380 GST_OBJECT_UNLOCK (pad);
1383 /* found a pad, stop search */
1384 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1385 GST_DEBUG_PAD_NAME (pad));
1386 GST_OBJECT_UNLOCK (pad);
1392 gst_object_ref (result);
1394 GST_OBJECT_UNLOCK (element);
1398 /* ERROR handling */
1401 g_warning ("unknown pad direction %d", dir);
1407 gst_element_default_send_event (GstElement * element, GstEvent * event)
1409 gboolean result = FALSE;
1412 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1413 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1414 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1417 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1418 "pushing %s event to random %s pad %s:%s",
1419 GST_EVENT_TYPE_NAME (event),
1420 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1421 GST_DEBUG_PAD_NAME (pad));
1423 result = gst_pad_push_event (pad, event);
1424 gst_object_unref (pad);
1426 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1427 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1428 gst_event_unref (event);
1434 * gst_element_send_event:
1435 * @element: a #GstElement to send the event to.
1436 * @event: (transfer full): the #GstEvent to send to the element.
1438 * Sends an event to an element. If the element doesn't implement an
1439 * event handler, the event will be pushed on a random linked sink pad for
1440 * upstream events or a random linked source pad for downstream events.
1442 * This function takes owership of the provided event so you should
1443 * gst_event_ref() it if you want to reuse the event after this call.
1445 * Returns: %TRUE if the event was handled.
1450 gst_element_send_event (GstElement * element, GstEvent * event)
1452 GstElementClass *oclass;
1453 gboolean result = FALSE;
1455 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1456 g_return_val_if_fail (event != NULL, FALSE);
1458 oclass = GST_ELEMENT_GET_CLASS (element);
1460 GST_STATE_LOCK (element);
1461 if (oclass->send_event) {
1462 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1463 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1464 result = oclass->send_event (element, event);
1466 GST_STATE_UNLOCK (element);
1473 * @element: a #GstElement to send the event to.
1474 * @rate: The new playback rate
1475 * @format: The format of the seek values
1476 * @flags: The optional seek flags.
1477 * @cur_type: The type and flags for the new current position
1478 * @cur: The value of the new current position
1479 * @stop_type: The type and flags for the new stop position
1480 * @stop: The value of the new stop position
1482 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1483 * the parameters. The seek event is sent to the element using
1484 * gst_element_send_event().
1486 * Returns: %TRUE if the event was handled.
1491 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1492 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1493 GstSeekType stop_type, gint64 stop)
1498 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1501 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1502 result = gst_element_send_event (element, event);
1508 gst_element_default_query (GstElement * element, GstQuery * query)
1510 gboolean result = FALSE;
1513 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1515 result = gst_pad_query (pad, query);
1517 gst_object_unref (pad);
1519 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1521 GstPad *peer = gst_pad_get_peer (pad);
1524 result = gst_pad_query (peer, query);
1526 gst_object_unref (peer);
1528 gst_object_unref (pad);
1535 * gst_element_query:
1536 * @element: a #GstElement to perform the query on.
1537 * @query: (transfer none): the #GstQuery.
1539 * Performs a query on the given element.
1541 * For elements that don't implement a query handler, this function
1542 * forwards the query to a random srcpad or to the peer of a
1543 * random linked sinkpad of this element.
1545 * Please note that some queries might need a running pipeline to work.
1547 * Returns: TRUE if the query could be performed.
1552 gst_element_query (GstElement * element, GstQuery * query)
1554 GstElementClass *oclass;
1555 gboolean result = FALSE;
1557 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1558 g_return_val_if_fail (query != NULL, FALSE);
1560 oclass = GST_ELEMENT_GET_CLASS (element);
1562 if (oclass->query) {
1563 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1564 GST_ELEMENT_NAME (element));
1565 result = oclass->query (element, query);
1571 * gst_element_post_message:
1572 * @element: a #GstElement posting the message
1573 * @message: (transfer full): a #GstMessage to post
1575 * Post a message on the element's #GstBus. This function takes ownership of the
1576 * message; if you want to access the message after this call, you should add an
1577 * additional reference before calling.
1579 * Returns: %TRUE if the message was successfully posted. The function returns
1580 * %FALSE if the element did not have a bus.
1585 gst_element_post_message (GstElement * element, GstMessage * message)
1588 gboolean result = FALSE;
1590 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1591 g_return_val_if_fail (message != NULL, FALSE);
1593 GST_OBJECT_LOCK (element);
1596 if (G_UNLIKELY (bus == NULL))
1599 gst_object_ref (bus);
1600 GST_OBJECT_UNLOCK (element);
1602 /* we release the element lock when posting the message so that any
1603 * (synchronous) message handlers can operate on the element */
1604 result = gst_bus_post (bus, message);
1605 gst_object_unref (bus);
1612 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1613 "not posting message %p: no bus", message);
1614 GST_OBJECT_UNLOCK (element);
1615 gst_message_unref (message);
1621 * _gst_element_error_printf:
1622 * @format: the printf-like format to use, or %NULL
1624 * This function is only used internally by the gst_element_error() macro.
1626 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1632 _gst_element_error_printf (const gchar * format, ...)
1642 va_start (args, format);
1643 buffer = g_strdup_vprintf (format, args);
1649 * gst_element_message_full:
1650 * @element: a #GstElement to send message from
1651 * @type: the #GstMessageType
1652 * @domain: the GStreamer GError domain this message belongs to
1653 * @code: the GError code belonging to the domain
1654 * @text: (allow-none) (transfer full): an allocated text string to be used
1655 * as a replacement for the default message connected to code,
1657 * @debug: (allow-none) (transfer full): an allocated debug message to be
1658 * used as a replacement for the default debugging information,
1660 * @file: the source code file where the error was generated
1661 * @function: the source code function where the error was generated
1662 * @line: the source code line where the error was generated
1664 * Post an error, warning or info message on the bus from inside an element.
1666 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1667 * #GST_MESSAGE_INFO.
1671 void gst_element_message_full
1672 (GstElement * element, GstMessageType type,
1673 GQuark domain, gint code, gchar * text,
1674 gchar * debug, const gchar * file, const gchar * function, gint line)
1676 GError *gerror = NULL;
1680 gboolean has_debug = TRUE;
1681 GstMessage *message = NULL;
1684 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1685 g_return_if_fail (GST_IS_ELEMENT (element));
1686 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1687 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1689 /* check if we send the given text or the default error text */
1690 if ((text == NULL) || (text[0] == 0)) {
1691 /* text could have come from g_strdup_printf (""); */
1693 sent_text = gst_error_get_message (domain, code);
1697 /* construct a sent_debug with extra information from source */
1698 if ((debug == NULL) || (debug[0] == 0)) {
1699 /* debug could have come from g_strdup_printf (""); */
1703 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1705 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1706 file, line, function, name, debug);
1708 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1709 file, line, function, name);
1713 /* create gerror and post message */
1714 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1716 gerror = g_error_new_literal (domain, code, sent_text);
1719 case GST_MESSAGE_ERROR:
1721 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1723 case GST_MESSAGE_WARNING:
1724 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1727 case GST_MESSAGE_INFO:
1728 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1732 g_assert_not_reached ();
1735 gst_element_post_message (element, message);
1737 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1738 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1741 g_error_free (gerror);
1742 g_free (sent_debug);
1747 * gst_element_is_locked_state:
1748 * @element: a #GstElement.
1750 * Checks if the state of an element is locked.
1751 * If the state of an element is locked, state changes of the parent don't
1752 * affect the element.
1753 * This way you can leave currently unused elements inside bins. Just lock their
1754 * state before changing the state from #GST_STATE_NULL.
1758 * Returns: TRUE, if the element's state is locked.
1761 gst_element_is_locked_state (GstElement * element)
1765 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1767 GST_OBJECT_LOCK (element);
1768 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1769 GST_OBJECT_UNLOCK (element);
1775 * gst_element_set_locked_state:
1776 * @element: a #GstElement
1777 * @locked_state: TRUE to lock the element's state
1779 * Locks the state of an element, so state changes of the parent don't affect
1780 * this element anymore.
1784 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1785 * or the elements state-locking needed no change.
1788 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1792 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1794 GST_OBJECT_LOCK (element);
1795 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1797 if (G_UNLIKELY (old == locked_state))
1801 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1802 GST_ELEMENT_NAME (element));
1803 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1805 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1806 GST_ELEMENT_NAME (element));
1807 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1809 GST_OBJECT_UNLOCK (element);
1815 GST_CAT_DEBUG (GST_CAT_STATES,
1816 "elements %s was already in locked state %d",
1817 GST_ELEMENT_NAME (element), old);
1818 GST_OBJECT_UNLOCK (element);
1825 * gst_element_sync_state_with_parent:
1826 * @element: a #GstElement.
1828 * Tries to change the state of the element to the same as its parent.
1829 * If this function returns FALSE, the state of element is undefined.
1831 * Returns: TRUE, if the element's state could be synced to the parent's state.
1836 gst_element_sync_state_with_parent (GstElement * element)
1840 GstStateChangeReturn ret;
1842 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1844 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1845 GstState parent_current, parent_pending;
1847 GST_OBJECT_LOCK (parent);
1848 parent_current = GST_STATE (parent);
1849 parent_pending = GST_STATE_PENDING (parent);
1850 GST_OBJECT_UNLOCK (parent);
1852 /* set to pending if there is one, else we set it to the current state of
1854 if (parent_pending != GST_STATE_VOID_PENDING)
1855 target = parent_pending;
1857 target = parent_current;
1859 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1860 "syncing state (%s) to parent %s %s (%s, %s)",
1861 gst_element_state_get_name (GST_STATE (element)),
1862 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1863 gst_element_state_get_name (parent_current),
1864 gst_element_state_get_name (parent_pending));
1866 ret = gst_element_set_state (element, target);
1867 if (ret == GST_STATE_CHANGE_FAILURE)
1870 gst_object_unref (parent);
1874 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1881 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1882 "syncing state failed (%s)",
1883 gst_element_state_change_return_get_name (ret));
1884 gst_object_unref (parent);
1890 static GstStateChangeReturn
1891 gst_element_get_state_func (GstElement * element,
1892 GstState * state, GstState * pending, GstClockTime timeout)
1894 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1895 GstState old_pending;
1897 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1898 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1900 GST_OBJECT_LOCK (element);
1901 ret = GST_STATE_RETURN (element);
1902 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1903 gst_element_state_change_return_get_name (ret));
1905 /* we got an error, report immediately */
1906 if (ret == GST_STATE_CHANGE_FAILURE)
1909 /* we got no_preroll, report immediately */
1910 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1913 /* no need to wait async if we are not async */
1914 if (ret != GST_STATE_CHANGE_ASYNC)
1917 old_pending = GST_STATE_PENDING (element);
1918 if (old_pending != GST_STATE_VOID_PENDING) {
1919 GTimeVal *timeval, abstimeout;
1922 if (timeout != GST_CLOCK_TIME_NONE) {
1923 glong add = timeout / 1000;
1928 /* make timeout absolute */
1929 g_get_current_time (&abstimeout);
1930 g_time_val_add (&abstimeout, add);
1931 timeval = &abstimeout;
1935 /* get cookie to detect state changes during waiting */
1936 cookie = element->state_cookie;
1938 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1939 "waiting for element to commit state");
1941 /* we have a pending state change, wait for it to complete */
1942 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1943 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1944 /* timeout triggered */
1945 ret = GST_STATE_CHANGE_ASYNC;
1947 if (cookie != element->state_cookie)
1950 /* could be success or failure */
1951 if (old_pending == GST_STATE (element)) {
1952 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1953 ret = GST_STATE_CHANGE_SUCCESS;
1955 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1956 ret = GST_STATE_CHANGE_FAILURE;
1959 /* if nothing is pending anymore we can return SUCCESS */
1960 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1961 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1962 ret = GST_STATE_CHANGE_SUCCESS;
1968 *state = GST_STATE (element);
1970 *pending = GST_STATE_PENDING (element);
1972 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1973 "state current: %s, pending: %s, result: %s",
1974 gst_element_state_get_name (GST_STATE (element)),
1975 gst_element_state_get_name (GST_STATE_PENDING (element)),
1976 gst_element_state_change_return_get_name (ret));
1977 GST_OBJECT_UNLOCK (element);
1984 *state = GST_STATE_VOID_PENDING;
1986 *pending = GST_STATE_VOID_PENDING;
1988 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
1990 GST_OBJECT_UNLOCK (element);
1992 return GST_STATE_CHANGE_FAILURE;
1997 * gst_element_get_state:
1998 * @element: a #GstElement to get the state of.
1999 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2001 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2002 * state. Can be %NULL.
2003 * @timeout: a #GstClockTime to specify the timeout for an async
2004 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2006 * Gets the state of the element.
2008 * For elements that performed an ASYNC state change, as reported by
2009 * gst_element_set_state(), this function will block up to the
2010 * specified timeout value for the state change to complete.
2011 * If the element completes the state change or goes into
2012 * an error, this function returns immediately with a return value of
2013 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2015 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2016 * returns the current and pending state immediately.
2018 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2019 * successfully changed its state but is not able to provide data yet.
2020 * This mostly happens for live sources that only produce data in
2021 * %GST_STATE_PLAYING. While the state change return is equivalent to
2022 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2023 * some sink elements might not be able to complete their state change because
2024 * an element is not producing data to complete the preroll. When setting the
2025 * element to playing, the preroll will complete and playback will start.
2027 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2028 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2029 * element is still performing a state change or
2030 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2034 GstStateChangeReturn
2035 gst_element_get_state (GstElement * element,
2036 GstState * state, GstState * pending, GstClockTime timeout)
2038 GstElementClass *oclass;
2039 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2041 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2043 oclass = GST_ELEMENT_GET_CLASS (element);
2045 if (oclass->get_state)
2046 result = (oclass->get_state) (element, state, pending, timeout);
2052 * gst_element_abort_state:
2053 * @element: a #GstElement to abort the state of.
2055 * Abort the state change of the element. This function is used
2056 * by elements that do asynchronous state changes and find out
2057 * something is wrong.
2059 * This function should be called with the STATE_LOCK held.
2064 gst_element_abort_state (GstElement * element)
2068 #ifndef GST_DISABLE_GST_DEBUG
2072 g_return_if_fail (GST_IS_ELEMENT (element));
2074 GST_OBJECT_LOCK (element);
2075 pending = GST_STATE_PENDING (element);
2077 if (pending == GST_STATE_VOID_PENDING ||
2078 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2079 goto nothing_aborted;
2081 #ifndef GST_DISABLE_GST_DEBUG
2082 old_state = GST_STATE (element);
2084 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2085 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2086 gst_element_state_get_name (pending));
2090 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2092 GST_STATE_BROADCAST (element);
2093 GST_OBJECT_UNLOCK (element);
2099 GST_OBJECT_UNLOCK (element);
2104 /* Not static because GstBin has manual state handling too */
2106 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2107 GstState newstate, GstState pending)
2109 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2110 GstMessage *message;
2112 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2113 "notifying about state-changed %s to %s (%s pending)",
2114 gst_element_state_get_name (oldstate),
2115 gst_element_state_get_name (newstate),
2116 gst_element_state_get_name (pending));
2118 if (klass->state_changed)
2119 klass->state_changed (element, oldstate, newstate, pending);
2121 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2122 oldstate, newstate, pending);
2123 gst_element_post_message (element, message);
2127 * gst_element_continue_state:
2128 * @element: a #GstElement to continue the state change of.
2129 * @ret: The previous state return value
2131 * Commit the state change of the element and proceed to the next
2132 * pending state if any. This function is used
2133 * by elements that do asynchronous state changes.
2134 * The core will normally call this method automatically when an
2135 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2137 * If after calling this method the element still has not reached
2138 * the pending state, the next state change is performed.
2140 * This method is used internally and should normally not be called by plugins
2143 * Returns: The result of the commit state change.
2147 GstStateChangeReturn
2148 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2150 GstStateChangeReturn old_ret;
2151 GstState old_state, old_next;
2152 GstState current, next, pending;
2153 GstStateChange transition;
2155 GST_OBJECT_LOCK (element);
2156 old_ret = GST_STATE_RETURN (element);
2157 GST_STATE_RETURN (element) = ret;
2158 pending = GST_STATE_PENDING (element);
2160 /* check if there is something to commit */
2161 if (pending == GST_STATE_VOID_PENDING)
2162 goto nothing_pending;
2164 old_state = GST_STATE (element);
2165 /* this is the state we should go to next */
2166 old_next = GST_STATE_NEXT (element);
2167 /* update current state */
2168 current = GST_STATE (element) = old_next;
2170 /* see if we reached the final state */
2171 if (pending == current)
2174 next = GST_STATE_GET_NEXT (current, pending);
2175 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2177 GST_STATE_NEXT (element) = next;
2179 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2180 GST_OBJECT_UNLOCK (element);
2182 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2183 "committing state from %s to %s, pending %s, next %s",
2184 gst_element_state_get_name (old_state),
2185 gst_element_state_get_name (old_next),
2186 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2188 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2190 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2191 "continue state change %s to %s, final %s",
2192 gst_element_state_get_name (current),
2193 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2195 ret = gst_element_change_state (element, transition);
2201 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2202 GST_OBJECT_UNLOCK (element);
2207 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2208 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2210 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2211 "completed state change to %s", gst_element_state_get_name (pending));
2212 GST_OBJECT_UNLOCK (element);
2214 /* don't post silly messages with the same state. This can happen
2215 * when an element state is changed to what it already was. For bins
2216 * this can be the result of a lost state, which we check with the
2217 * previous return value.
2218 * We do signal the cond though as a _get_state() might be blocking
2220 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2221 _priv_gst_element_state_changed (element, old_state, old_next,
2222 GST_STATE_VOID_PENDING);
2224 GST_STATE_BROADCAST (element);
2231 * gst_element_lost_state:
2232 * @element: a #GstElement the state is lost of
2234 * Brings the element to the lost state. The current state of the
2235 * element is copied to the pending state so that any call to
2236 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2238 * An ASYNC_START message is posted. If the element was PLAYING, it will
2239 * go to PAUSED. The element will be restored to its PLAYING state by
2240 * the parent pipeline when it prerolls again.
2242 * This is mostly used for elements that lost their preroll buffer
2243 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2244 * they will go to their pending state again when a new preroll buffer is
2245 * queued. This function can only be called when the element is currently
2246 * not in error or an async state change.
2248 * This function is used internally and should normally not be called from
2249 * plugins or applications.
2252 gst_element_lost_state (GstElement * element)
2254 GstState old_state, new_state;
2255 GstMessage *message;
2257 g_return_if_fail (GST_IS_ELEMENT (element));
2259 GST_OBJECT_LOCK (element);
2260 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2263 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2264 goto only_async_start;
2266 old_state = GST_STATE (element);
2268 /* when we were PLAYING, the new state is PAUSED. We will also not
2269 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2270 * when we preroll. */
2271 if (old_state > GST_STATE_PAUSED)
2272 new_state = GST_STATE_PAUSED;
2274 new_state = old_state;
2276 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2277 "lost state of %s to %s", gst_element_state_get_name (old_state),
2278 gst_element_state_get_name (new_state));
2280 GST_STATE (element) = new_state;
2281 GST_STATE_NEXT (element) = new_state;
2282 GST_STATE_PENDING (element) = new_state;
2283 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2284 GST_OBJECT_UNLOCK (element);
2286 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2288 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2289 gst_element_post_message (element, message);
2295 GST_OBJECT_UNLOCK (element);
2300 GST_OBJECT_UNLOCK (element);
2302 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2303 gst_element_post_message (element, message);
2309 * gst_element_set_state:
2310 * @element: a #GstElement to change state of.
2311 * @state: the element's new #GstState.
2313 * Sets the state of the element. This function will try to set the
2314 * requested state by going through all the intermediary states and calling
2315 * the class's state change function for each.
2317 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2318 * element will perform the remainder of the state change asynchronously in
2320 * An application can use gst_element_get_state() to wait for the completion
2321 * of the state change or it can wait for a state change message on the bus.
2323 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2324 * #GST_STATE_CHANGE_ASYNC.
2326 * Returns: Result of the state change using #GstStateChangeReturn.
2330 GstStateChangeReturn
2331 gst_element_set_state (GstElement * element, GstState state)
2333 GstElementClass *oclass;
2334 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2336 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2338 oclass = GST_ELEMENT_GET_CLASS (element);
2340 if (oclass->set_state)
2341 result = (oclass->set_state) (element, state);
2347 * default set state function, calculates the next state based
2348 * on current state and calls the change_state function
2350 static GstStateChangeReturn
2351 gst_element_set_state_func (GstElement * element, GstState state)
2353 GstState current, next, old_pending;
2354 GstStateChangeReturn ret;
2355 GstStateChange transition;
2356 GstStateChangeReturn old_ret;
2358 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2360 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2361 gst_element_state_get_name (state));
2363 /* state lock is taken to protect the set_state() and get_state()
2364 * procedures, it does not lock any variables. */
2365 GST_STATE_LOCK (element);
2367 /* now calculate how to get to the new state */
2368 GST_OBJECT_LOCK (element);
2369 old_ret = GST_STATE_RETURN (element);
2370 /* previous state change returned an error, remove all pending
2371 * and next states */
2372 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2373 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2374 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2375 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2378 current = GST_STATE (element);
2379 next = GST_STATE_NEXT (element);
2380 old_pending = GST_STATE_PENDING (element);
2382 /* this is the (new) state we should go to. TARGET is the last state we set on
2384 if (state != GST_STATE_TARGET (element)) {
2385 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2386 "setting target state to %s", gst_element_state_get_name (state));
2387 GST_STATE_TARGET (element) = state;
2388 /* increment state cookie so that we can track each state change. We only do
2389 * this if this is actually a new state change. */
2390 element->state_cookie++;
2392 GST_STATE_PENDING (element) = state;
2394 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2395 "current %s, old_pending %s, next %s, old return %s",
2396 gst_element_state_get_name (current),
2397 gst_element_state_get_name (old_pending),
2398 gst_element_state_get_name (next),
2399 gst_element_state_change_return_get_name (old_ret));
2401 /* if the element was busy doing a state change, we just update the
2402 * target state, it'll get to it async then. */
2403 if (old_pending != GST_STATE_VOID_PENDING) {
2404 /* upwards state change will happen ASYNC */
2405 if (old_pending <= state)
2407 /* element is going to this state already */
2408 else if (next == state)
2410 /* element was performing an ASYNC upward state change and
2411 * we request to go downward again. Start from the next pending
2413 else if (next > state
2414 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2418 next = GST_STATE_GET_NEXT (current, state);
2419 /* now we store the next state */
2420 GST_STATE_NEXT (element) = next;
2421 /* mark busy, we need to check that there is actually a state change
2422 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2423 * the default element change_state function has no way to know what the
2424 * old value was... could consider this a FIXME...*/
2425 if (current != next)
2426 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2428 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2430 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2431 "%s: setting state from %s to %s",
2432 (next != state ? "intermediate" : "final"),
2433 gst_element_state_get_name (current), gst_element_state_get_name (next));
2435 /* now signal any waiters, they will error since the cookie was incremented */
2436 GST_STATE_BROADCAST (element);
2438 GST_OBJECT_UNLOCK (element);
2440 ret = gst_element_change_state (element, transition);
2442 GST_STATE_UNLOCK (element);
2444 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2445 gst_element_state_change_return_get_name (ret));
2451 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2452 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2453 "element was busy with async state change");
2454 GST_OBJECT_UNLOCK (element);
2456 GST_STATE_UNLOCK (element);
2458 return GST_STATE_CHANGE_ASYNC;
2463 * gst_element_change_state:
2464 * @element: a #GstElement
2465 * @transition: the requested transition
2467 * Perform @transition on @element.
2469 * This function must be called with STATE_LOCK held and is mainly used
2472 * Returns: the #GstStateChangeReturn of the state transition.
2474 GstStateChangeReturn
2475 gst_element_change_state (GstElement * element, GstStateChange transition)
2477 GstElementClass *oclass;
2478 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2480 oclass = GST_ELEMENT_GET_CLASS (element);
2482 /* call the state change function so it can set the state */
2483 if (oclass->change_state)
2484 ret = (oclass->change_state) (element, transition);
2486 ret = GST_STATE_CHANGE_FAILURE;
2489 case GST_STATE_CHANGE_FAILURE:
2490 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2491 "have FAILURE change_state return");
2492 /* state change failure */
2493 gst_element_abort_state (element);
2495 case GST_STATE_CHANGE_ASYNC:
2499 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2500 "element will change state ASYNC");
2502 target = GST_STATE_TARGET (element);
2504 if (target > GST_STATE_READY)
2507 /* else we just continue the state change downwards */
2508 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2509 "forcing commit state %s <= %s",
2510 gst_element_state_get_name (target),
2511 gst_element_state_get_name (GST_STATE_READY));
2513 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2516 case GST_STATE_CHANGE_SUCCESS:
2517 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2518 "element changed state SUCCESS");
2519 /* we can commit the state now which will proceeed to
2521 ret = gst_element_continue_state (element, ret);
2523 case GST_STATE_CHANGE_NO_PREROLL:
2524 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2525 "element changed state NO_PREROLL");
2526 /* we can commit the state now which will proceeed to
2528 ret = gst_element_continue_state (element, ret);
2531 goto invalid_return;
2534 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2539 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2547 GST_OBJECT_LOCK (element);
2548 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2549 g_critical ("%s: unknown return value %d from a state change function",
2550 GST_ELEMENT_NAME (element), ret);
2552 /* we are in error now */
2553 ret = GST_STATE_CHANGE_FAILURE;
2554 GST_STATE_RETURN (element) = ret;
2555 GST_OBJECT_UNLOCK (element);
2561 /* gst_iterator_fold functions for pads_activate
2562 * Stop the iterator if activating one pad failed. */
2564 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2566 GstPad *pad = g_value_get_object (vpad);
2567 gboolean cont = TRUE;
2569 if (!(cont = gst_pad_set_active (pad, *active)))
2570 g_value_set_boolean (ret, FALSE);
2575 /* returns false on error or early cutout of the fold, true if all
2576 * pads in @iter were (de)activated successfully. */
2578 iterator_activate_fold_with_resync (GstIterator * iter,
2579 GstIteratorFoldFunction func, gpointer user_data)
2581 GstIteratorResult ires;
2584 /* no need to unset this later, it's just a boolean */
2585 g_value_init (&ret, G_TYPE_BOOLEAN);
2586 g_value_set_boolean (&ret, TRUE);
2589 ires = gst_iterator_fold (iter, func, &ret, user_data);
2591 case GST_ITERATOR_RESYNC:
2592 /* need to reset the result again */
2593 g_value_set_boolean (&ret, TRUE);
2594 gst_iterator_resync (iter);
2596 case GST_ITERATOR_DONE:
2597 /* all pads iterated, return collected value */
2600 /* iterator returned _ERROR or premature end with _OK,
2601 * mark an error and exit */
2602 g_value_set_boolean (&ret, FALSE);
2607 /* return collected value */
2608 return g_value_get_boolean (&ret);
2611 /* is called with STATE_LOCK
2613 * Pads are activated from source pads to sinkpads.
2616 gst_element_pads_activate (GstElement * element, gboolean active)
2621 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2622 "pads_activate with active %d", active);
2624 iter = gst_element_iterate_src_pads (element);
2626 iterator_activate_fold_with_resync (iter,
2627 (GstIteratorFoldFunction) activate_pads, &active);
2628 gst_iterator_free (iter);
2629 if (G_UNLIKELY (!res))
2632 iter = gst_element_iterate_sink_pads (element);
2634 iterator_activate_fold_with_resync (iter,
2635 (GstIteratorFoldFunction) activate_pads, &active);
2636 gst_iterator_free (iter);
2637 if (G_UNLIKELY (!res))
2640 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2641 "pads_activate successful");
2648 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2649 "source pads_activate failed");
2654 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2655 "sink pads_activate failed");
2660 /* is called with STATE_LOCK */
2661 static GstStateChangeReturn
2662 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2664 GstState state, next;
2665 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2667 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2669 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2670 next = GST_STATE_TRANSITION_NEXT (transition);
2672 /* if the element already is in the given state, we just return success */
2673 if (next == GST_STATE_VOID_PENDING || state == next)
2676 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2677 "default handler tries setting state from %s to %s (%04x)",
2678 gst_element_state_get_name (state),
2679 gst_element_state_get_name (next), transition);
2681 switch (transition) {
2682 case GST_STATE_CHANGE_NULL_TO_READY:
2684 case GST_STATE_CHANGE_READY_TO_PAUSED:
2685 if (!gst_element_pads_activate (element, TRUE)) {
2686 result = GST_STATE_CHANGE_FAILURE;
2689 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2691 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2693 case GST_STATE_CHANGE_PAUSED_TO_READY:
2694 case GST_STATE_CHANGE_READY_TO_NULL:
2695 /* deactivate pads in both cases, since they are activated on
2696 ready->paused but the element might not have made it to paused */
2697 if (!gst_element_pads_activate (element, FALSE)) {
2698 result = GST_STATE_CHANGE_FAILURE;
2702 /* this will catch real but unhandled state changes;
2703 * can only be caused by:
2704 * - a new state was added
2705 * - somehow the element was asked to jump across an intermediate state
2707 g_warning ("Unhandled state change from %s to %s",
2708 gst_element_state_get_name (state),
2709 gst_element_state_get_name (next));
2716 GST_OBJECT_LOCK (element);
2717 result = GST_STATE_RETURN (element);
2718 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2719 "element is already in the %s state",
2720 gst_element_state_get_name (state));
2721 GST_OBJECT_UNLOCK (element);
2728 * gst_element_get_factory:
2729 * @element: a #GstElement to request the element factory of.
2731 * Retrieves the factory that was used to create this element.
2733 * Returns: (transfer none): the #GstElementFactory used for creating this
2734 * element. no refcounting is needed.
2737 gst_element_get_factory (GstElement * element)
2739 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2741 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2745 gst_element_dispose (GObject * object)
2747 GstElement *element = GST_ELEMENT_CAST (object);
2751 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2753 if (GST_STATE (element) != GST_STATE_NULL)
2756 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2757 "removing %d pads", g_list_length (element->pads));
2758 /* first we break all our links with the outside */
2759 while (element->pads && element->pads->data) {
2760 /* don't call _remove_pad with NULL */
2761 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2763 if (G_UNLIKELY (element->pads != NULL)) {
2764 g_critical ("could not remove pads from element %s",
2765 GST_STR_NULL (GST_OBJECT_NAME (object)));
2768 GST_OBJECT_LOCK (element);
2769 clock_p = &element->clock;
2770 bus_p = &element->bus;
2771 gst_object_replace ((GstObject **) clock_p, NULL);
2772 gst_object_replace ((GstObject **) bus_p, NULL);
2773 GST_OBJECT_UNLOCK (element);
2775 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2777 G_OBJECT_CLASS (parent_class)->dispose (object);
2786 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2788 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2790 "You need to explicitly set elements to the NULL state before\n"
2791 "dropping the final reference, to allow them to clean up.\n"
2792 "This problem may also be caused by a refcounting bug in the\n"
2793 "application or some element.\n",
2794 GST_OBJECT_NAME (element),
2795 gst_element_state_get_name (GST_STATE (element)),
2796 is_locked ? " (locked)" : "");
2802 gst_element_finalize (GObject * object)
2804 GstElement *element = GST_ELEMENT_CAST (object);
2806 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2808 g_cond_free (element->state_cond);
2809 g_static_rec_mutex_free (&element->state_lock);
2811 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2813 G_OBJECT_CLASS (parent_class)->finalize (object);
2817 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2821 g_return_if_fail (GST_IS_ELEMENT (element));
2823 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2825 GST_OBJECT_LOCK (element);
2826 bus_p = &GST_ELEMENT_BUS (element);
2827 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2828 GST_OBJECT_UNLOCK (element);
2832 * gst_element_set_bus:
2833 * @element: a #GstElement to set the bus of.
2834 * @bus: (transfer none): the #GstBus to set.
2836 * Sets the bus of the element. Increases the refcount on the bus.
2837 * For internal use only, unless you're testing elements.
2842 gst_element_set_bus (GstElement * element, GstBus * bus)
2844 GstElementClass *oclass;
2846 g_return_if_fail (GST_IS_ELEMENT (element));
2848 oclass = GST_ELEMENT_GET_CLASS (element);
2850 if (oclass->set_bus)
2851 oclass->set_bus (element, bus);
2855 * gst_element_get_bus:
2856 * @element: a #GstElement to get the bus of.
2858 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2859 * bus for the application.
2861 * Returns: (transfer full): the element's #GstBus. unref after usage.
2866 gst_element_get_bus (GstElement * element)
2868 GstBus *result = NULL;
2870 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2872 GST_OBJECT_LOCK (element);
2873 if ((result = GST_ELEMENT_BUS (element)))
2874 gst_object_ref (result);
2875 GST_OBJECT_UNLOCK (element);
2877 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,