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 * Elements can 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_\%u".
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 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. 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 the
72 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, 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 2012-03-28 (0.11.3)
82 #include "gst_private.h"
85 #include <gobject/gvaluecollector.h>
87 #include "gstelement.h"
88 #include "gstelementmetadata.h"
89 #include "gstenumtypes.h"
97 #include "gst-i18n-lib.h"
98 #include "glib-compat-private.h"
100 /* Element signals and args */
116 static void gst_element_class_init (GstElementClass * klass);
117 static void gst_element_init (GstElement * element);
118 static void gst_element_base_class_init (gpointer g_class);
119 static void gst_element_base_class_finalize (gpointer g_class);
121 static void gst_element_dispose (GObject * object);
122 static void gst_element_finalize (GObject * object);
124 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
125 GstStateChange transition);
126 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
127 GstState * state, GstState * pending, GstClockTime timeout);
128 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
130 static gboolean gst_element_set_clock_func (GstElement * element,
132 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
134 static gboolean gst_element_default_send_event (GstElement * element,
136 static gboolean gst_element_default_query (GstElement * element,
139 static GstPadTemplate
140 * gst_element_class_get_request_pad_template (GstElementClass *
141 element_class, const gchar * name);
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;
184 gobject_class = (GObjectClass *) klass;
186 parent_class = g_type_class_peek_parent (klass);
189 * GstElement::pad-added:
190 * @gstelement: the object which received the signal
191 * @new_pad: the pad that has been added
193 * a new #GstPad has been added to the element. Note that this signal will
194 * usually be emitted from the context of the streaming thread. Also keep in
195 * mind that if you add new elements to the pipeline in the signal handler
196 * you will need to set them to the desired target state with
197 * gst_element_set_state() or gst_element_sync_state_with_parent().
199 gst_element_signals[PAD_ADDED] =
200 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
201 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
202 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
204 * GstElement::pad-removed:
205 * @gstelement: the object which received the signal
206 * @old_pad: the pad that has been removed
208 * a #GstPad has been removed from the element
210 gst_element_signals[PAD_REMOVED] =
211 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
212 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
213 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
215 * GstElement::no-more-pads:
216 * @gstelement: the object which received the signal
218 * This signals that the element will not generate more dynamic pads.
219 * Note that this signal will usually be emitted from the context of
220 * the streaming thread.
222 gst_element_signals[NO_MORE_PADS] =
223 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
224 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
225 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
227 gobject_class->dispose = gst_element_dispose;
228 gobject_class->finalize = gst_element_finalize;
230 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
231 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
232 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
233 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
234 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
235 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
236 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
237 klass->numpadtemplates = 0;
239 klass->elementfactory = NULL;
243 gst_element_base_class_init (gpointer g_class)
245 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
246 GList *node, *padtemplates;
248 /* Copy the element details here so elements can inherit the
249 * details from their base class and classes only need to set
250 * the details in class_init instead of base_init */
251 element_class->metadata =
252 element_class->metadata ? gst_structure_copy (element_class->metadata) :
253 gst_structure_new_empty ("metadata");
255 /* Copy the pad templates so elements inherit them
256 * from their base class but elements can add pad templates in class_init
257 * instead of base_init.
259 padtemplates = g_list_copy (element_class->padtemplates);
260 for (node = padtemplates; node != NULL; node = node->next) {
261 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
262 gst_object_ref (tmpl);
264 element_class->padtemplates = padtemplates;
266 /* set the factory, see gst_element_register() */
267 element_class->elementfactory =
268 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
269 __gst_elementclass_factory);
270 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
271 element_class->elementfactory);
275 gst_element_base_class_finalize (gpointer g_class)
277 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
279 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
280 g_list_free (klass->padtemplates);
282 gst_structure_free (klass->metadata);
286 gst_element_init (GstElement * element)
288 GST_STATE (element) = GST_STATE_NULL;
289 GST_STATE_TARGET (element) = GST_STATE_NULL;
290 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
291 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
292 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
294 g_rec_mutex_init (&element->state_lock);
295 g_cond_init (&element->state_cond);
299 * gst_element_release_request_pad:
300 * @element: a #GstElement to release the request pad of.
301 * @pad: the #GstPad to release.
303 * Makes the element free the previously requested pad as obtained
304 * with gst_element_get_request_pad().
306 * This does not unref the pad. If the pad was created by using
307 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
308 * followed by gst_object_unref() to free the @pad.
313 gst_element_release_request_pad (GstElement * element, GstPad * pad)
315 GstElementClass *oclass;
317 g_return_if_fail (GST_IS_ELEMENT (element));
318 g_return_if_fail (GST_IS_PAD (pad));
319 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
320 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
323 oclass = GST_ELEMENT_GET_CLASS (element);
325 /* if the element implements a custom release function we call that, else we
326 * simply remove the pad from the element */
327 if (oclass->release_pad)
328 oclass->release_pad (element, pad);
330 gst_element_remove_pad (element, pad);
334 * gst_element_provide_clock:
335 * @element: a #GstElement to query
337 * Get the clock provided by the given element.
338 * <note>An element is only required to provide a clock in the PAUSED
339 * state. Some elements can provide a clock in other states.</note>
341 * Returns: (transfer full): the GstClock provided by the element or %NULL
342 * if no clock could be provided. Unref after usage.
347 gst_element_provide_clock (GstElement * element)
349 GstClock *result = NULL;
350 GstElementClass *oclass;
352 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
354 oclass = GST_ELEMENT_GET_CLASS (element);
356 if (oclass->provide_clock)
357 result = oclass->provide_clock (element);
363 gst_element_set_clock_func (GstElement * element, GstClock * clock)
367 GST_OBJECT_LOCK (element);
368 clock_p = &element->clock;
369 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
370 GST_OBJECT_UNLOCK (element);
376 * gst_element_set_clock:
377 * @element: a #GstElement to set the clock for.
378 * @clock: the #GstClock to set for the element.
380 * Sets the clock for the element. This function increases the
381 * refcount on the clock. Any previously set clock on the object
384 * Returns: %TRUE if the element accepted the clock. An element can refuse a
385 * clock when it, for example, is not able to slave its internal clock to the
386 * @clock or when it requires a specific clock to operate.
391 gst_element_set_clock (GstElement * element, GstClock * clock)
393 GstElementClass *oclass;
394 gboolean res = FALSE;
396 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
397 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
399 oclass = GST_ELEMENT_GET_CLASS (element);
401 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
403 if (oclass->set_clock)
404 res = oclass->set_clock (element, clock);
410 * gst_element_get_clock:
411 * @element: a #GstElement to get the clock of.
413 * Gets the currently configured clock of the element. This is the clock as was
414 * last set with gst_element_set_clock().
416 * Returns: (transfer full): the #GstClock of the element. unref after usage.
421 gst_element_get_clock (GstElement * element)
425 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
427 GST_OBJECT_LOCK (element);
428 if ((result = element->clock))
429 gst_object_ref (result);
430 GST_OBJECT_UNLOCK (element);
436 * gst_element_set_base_time:
437 * @element: a #GstElement.
438 * @time: the base time to set.
440 * Set the base time of an element. See gst_element_get_base_time().
445 gst_element_set_base_time (GstElement * element, GstClockTime time)
449 g_return_if_fail (GST_IS_ELEMENT (element));
451 GST_OBJECT_LOCK (element);
452 old = element->base_time;
453 element->base_time = time;
454 GST_OBJECT_UNLOCK (element);
456 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
457 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
458 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
462 * gst_element_get_base_time:
463 * @element: a #GstElement.
465 * Returns the base time of the element. The base time is the
466 * absolute time of the clock when this element was last put to
467 * PLAYING. Subtracting the base time from the clock time gives
468 * the running time of the element.
470 * Returns: the base time of the element.
475 gst_element_get_base_time (GstElement * element)
479 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
481 GST_OBJECT_LOCK (element);
482 result = element->base_time;
483 GST_OBJECT_UNLOCK (element);
489 * gst_element_set_start_time:
490 * @element: a #GstElement.
491 * @time: the base time to set.
493 * Set the start time of an element. The start time of the element is the
494 * running time of the element when it last went to the PAUSED state. In READY
495 * or after a flushing seek, it is set to 0.
497 * Toplevel elements like #GstPipeline will manage the start_time and
498 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
499 * on such a toplevel element will disable the distribution of the base_time to
500 * the children and can be useful if the application manages the base_time
501 * itself, for example if you want to synchronize capture from multiple
502 * pipelines, and you can also ensure that the pipelines have the same clock.
507 gst_element_set_start_time (GstElement * element, GstClockTime time)
511 g_return_if_fail (GST_IS_ELEMENT (element));
513 GST_OBJECT_LOCK (element);
514 old = GST_ELEMENT_START_TIME (element);
515 GST_ELEMENT_START_TIME (element) = time;
516 GST_OBJECT_UNLOCK (element);
518 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
519 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
520 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
524 * gst_element_get_start_time:
525 * @element: a #GstElement.
527 * Returns the start time of the element. The start time is the
528 * running time of the clock when this element was last put to PAUSED.
530 * Usually the start_time is managed by a toplevel element such as
535 * 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);
553 * gst_element_set_index:
554 * @element: a #GstElement.
555 * @index: (transfer none): a #GstIndex.
557 * Set @index on the element. The refcount of the index
558 * will be increased, any previously set index is unreffed.
563 gst_element_set_index (GstElement * element, GstIndex * index)
565 GstElementClass *oclass;
567 g_return_if_fail (GST_IS_ELEMENT (element));
568 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
570 oclass = GST_ELEMENT_GET_CLASS (element);
572 if (oclass->set_index)
573 oclass->set_index (element, index);
577 * gst_element_get_index:
578 * @element: a #GstElement.
580 * Gets the index from the element.
582 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
583 * element. unref after usage.
588 gst_element_get_index (GstElement * element)
590 GstElementClass *oclass;
591 GstIndex *result = NULL;
593 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
595 oclass = GST_ELEMENT_GET_CLASS (element);
597 if (oclass->get_index)
598 result = oclass->get_index (element);
605 * gst_element_add_pad:
606 * @element: a #GstElement to add the pad to.
607 * @pad: (transfer full): the #GstPad to add to the element.
609 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
610 * see gst_object_set_parent() for refcounting information.
612 * Pads are not automatically activated so elements should perform the needed
613 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
614 * state. See gst_pad_set_active() for more information about activating pads.
616 * The pad and the element should be unlocked when calling this function.
618 * This function will emit the #GstElement::pad-added signal on the element.
620 * Returns: %TRUE if the pad could be added. This function can fail when
621 * a pad with the same name already existed or the pad already had another
627 gst_element_add_pad (GstElement * element, GstPad * pad)
632 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
633 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
635 /* locking pad to look at the name */
636 GST_OBJECT_LOCK (pad);
637 pad_name = g_strdup (GST_PAD_NAME (pad));
638 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
639 GST_STR_NULL (pad_name));
640 flushing = GST_PAD_IS_FLUSHING (pad);
641 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
642 GST_OBJECT_UNLOCK (pad);
644 /* then check to see if there's already a pad by that name here */
645 GST_OBJECT_LOCK (element);
646 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
649 /* try to set the pad's parent */
650 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
651 GST_OBJECT_CAST (element))))
654 /* check for flushing pads */
655 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
656 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
657 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
658 "use gst_pad_set_active(pad,TRUE) before adding it.",
659 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
661 GST_OBJECT_LOCK (pad);
662 GST_PAD_UNSET_FLUSHING (pad);
663 GST_OBJECT_UNLOCK (pad);
668 /* add it to the list */
669 switch (gst_pad_get_direction (pad)) {
671 element->srcpads = g_list_prepend (element->srcpads, pad);
672 element->numsrcpads++;
675 element->sinkpads = g_list_prepend (element->sinkpads, pad);
676 element->numsinkpads++;
681 element->pads = g_list_prepend (element->pads, pad);
683 element->pads_cookie++;
684 GST_OBJECT_UNLOCK (element);
686 /* emit the PAD_ADDED signal */
687 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
694 g_critical ("Padname %s is not unique in element %s, not adding",
695 pad_name, GST_ELEMENT_NAME (element));
696 GST_OBJECT_UNLOCK (element);
703 ("Pad %s already has parent when trying to add to element %s",
704 pad_name, GST_ELEMENT_NAME (element));
705 GST_OBJECT_UNLOCK (element);
711 GST_OBJECT_LOCK (pad);
713 ("Trying to add pad %s to element %s, but it has no direction",
714 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
715 GST_OBJECT_UNLOCK (pad);
716 GST_OBJECT_UNLOCK (element);
722 * gst_element_remove_pad:
723 * @element: a #GstElement to remove pad from.
724 * @pad: (transfer full): the #GstPad to remove from the element.
726 * Removes @pad from @element. @pad will be destroyed if it has not been
727 * referenced elsewhere using gst_object_unparent().
729 * This function is used by plugin developers and should not be used
730 * by applications. Pads that were dynamically requested from elements
731 * with gst_element_get_request_pad() should be released with the
732 * gst_element_release_request_pad() function instead.
734 * Pads are not automatically deactivated so elements should perform the needed
735 * steps to deactivate the pad in case this pad is removed in the PAUSED or
736 * PLAYING state. See gst_pad_set_active() for more information about
739 * The pad and the element should be unlocked when calling this function.
741 * This function will emit the #GstElement::pad-removed signal on the element.
743 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
744 * pad does not belong to the provided element.
749 gst_element_remove_pad (GstElement * element, GstPad * pad)
753 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
754 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
756 /* locking pad to look at the name and parent */
757 GST_OBJECT_LOCK (pad);
758 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
759 GST_STR_NULL (GST_PAD_NAME (pad)));
761 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
763 GST_OBJECT_UNLOCK (pad);
766 if ((peer = gst_pad_get_peer (pad))) {
767 /* window for MT unsafeness, someone else could unlink here
768 * and then we call unlink with wrong pads. The unlink
769 * function would catch this and safely return failed. */
770 if (GST_PAD_IS_SRC (pad))
771 gst_pad_unlink (pad, peer);
773 gst_pad_unlink (peer, pad);
775 gst_object_unref (peer);
778 GST_OBJECT_LOCK (element);
779 /* remove it from the list */
780 switch (gst_pad_get_direction (pad)) {
782 element->srcpads = g_list_remove (element->srcpads, pad);
783 element->numsrcpads--;
786 element->sinkpads = g_list_remove (element->sinkpads, pad);
787 element->numsinkpads--;
790 g_critical ("Removing pad without direction???");
793 element->pads = g_list_remove (element->pads, pad);
795 element->pads_cookie++;
796 GST_OBJECT_UNLOCK (element);
798 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
799 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
801 gst_object_unparent (GST_OBJECT_CAST (pad));
808 /* locking order is element > pad */
809 GST_OBJECT_UNLOCK (pad);
811 GST_OBJECT_LOCK (element);
812 GST_OBJECT_LOCK (pad);
813 g_critical ("Padname %s:%s does not belong to element %s when removing",
814 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
815 GST_OBJECT_UNLOCK (pad);
816 GST_OBJECT_UNLOCK (element);
822 * gst_element_no_more_pads:
823 * @element: a #GstElement
825 * Use this function to signal that the element does not expect any more pads
826 * to show up in the current pipeline. This function should be called whenever
827 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
828 * pad templates use this in combination with autopluggers to figure out that
829 * the element is done initializing its pads.
831 * This function emits the #GstElement::no-more-pads signal.
836 gst_element_no_more_pads (GstElement * element)
838 g_return_if_fail (GST_IS_ELEMENT (element));
840 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
844 pad_compare_name (GstPad * pad1, const gchar * name)
848 GST_OBJECT_LOCK (pad1);
849 result = strcmp (GST_PAD_NAME (pad1), name);
850 GST_OBJECT_UNLOCK (pad1);
856 * gst_element_get_static_pad:
857 * @element: a #GstElement to find a static pad of.
858 * @name: the name of the static #GstPad to retrieve.
860 * Retrieves a pad from @element by name. This version only retrieves
861 * already-existing (i.e. 'static') pads.
863 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
869 gst_element_get_static_pad (GstElement * element, const gchar * name)
872 GstPad *result = NULL;
874 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
875 g_return_val_if_fail (name != NULL, NULL);
877 GST_OBJECT_LOCK (element);
879 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
881 result = GST_PAD_CAST (find->data);
882 gst_object_ref (result);
885 if (result == NULL) {
886 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
887 name, GST_ELEMENT_NAME (element));
889 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
890 GST_ELEMENT_NAME (element), name);
892 GST_OBJECT_UNLOCK (element);
898 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
899 const gchar * name, const GstCaps * caps)
901 GstPad *newpad = NULL;
902 GstElementClass *oclass;
904 oclass = GST_ELEMENT_GET_CLASS (element);
906 #ifndef G_DISABLE_CHECKS
907 /* Some sanity checking here */
911 /* Is this the template name? */
912 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
913 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
915 const gchar *str, *data;
918 /* Otherwise check if it's a valid name for the name template */
919 str = strchr (templ->name_template, '%');
920 g_return_val_if_fail (str != NULL, NULL);
921 g_return_val_if_fail (strncmp (templ->name_template, name,
922 str - templ->name_template) == 0, NULL);
923 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
925 data = name + (str - templ->name_template);
927 /* Can either be %s or %d or %u, do sanity checking for %d */
928 if (*(str + 1) == 'd') {
932 tmp = g_ascii_strtoll (data, &endptr, 10);
933 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
934 && *endptr == '\0', NULL);
935 } else if (*(str + 1) == 'u') {
939 tmp = g_ascii_strtoull (data, &endptr, 10);
940 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
944 pad = gst_element_get_static_pad (element, name);
946 gst_object_unref (pad);
947 /* FIXME 0.11: Change this to g_return_val_if_fail() */
948 g_critical ("Element %s already has a pad named %s, the behaviour of "
949 " gst_element_get_request_pad() for existing pads is undefined!",
950 GST_ELEMENT_NAME (element), name);
955 if (oclass->request_new_pad)
956 newpad = (oclass->request_new_pad) (element, templ, name, caps);
959 gst_object_ref (newpad);
965 * gst_element_get_request_pad:
966 * @element: a #GstElement to find a request pad of.
967 * @name: the name of the request #GstPad to retrieve.
969 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
970 * retrieves request pads. The pad should be released with
971 * gst_element_release_request_pad().
973 * This method is slow and will be deprecated in the future. New code should
974 * use gst_element_request_pad() with the requested template.
976 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
977 * Release after usage.
980 gst_element_get_request_pad (GstElement * element, const gchar * name)
982 GstPadTemplate *templ = NULL;
984 const gchar *req_name = NULL;
985 gboolean templ_found = FALSE;
988 gchar *str, *endptr = NULL;
989 GstElementClass *class;
991 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
992 g_return_val_if_fail (name != NULL, NULL);
994 class = GST_ELEMENT_GET_CLASS (element);
996 /* if the name contains a %, we assume it's the complete template name. Get
997 * the template and try to get a pad */
998 if (strstr (name, "%")) {
999 templ = gst_element_class_get_request_pad_template (class, name);
1004 /* there is no % in the name, try to find a matching template */
1005 list = class->padtemplates;
1006 while (!templ_found && list) {
1007 templ = (GstPadTemplate *) list->data;
1008 if (templ->presence == GST_PAD_REQUEST) {
1009 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1010 templ->name_template);
1011 /* see if we find an exact match */
1012 if (strcmp (name, templ->name_template) == 0) {
1017 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1018 and %d and %u, occurring at the end of the name_template, are the only
1020 else if ((str = strchr (templ->name_template, '%'))
1021 && strncmp (templ->name_template, name,
1022 str - templ->name_template) == 0
1023 && strlen (name) > str - templ->name_template) {
1024 data = name + (str - templ->name_template);
1025 if (*(str + 1) == 'd') {
1029 tmp = strtol (data, &endptr, 10);
1030 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1036 } else if (*(str + 1) == 'u') {
1040 tmp = strtoul (data, &endptr, 10);
1041 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1061 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1067 * gst_element_request_pad:
1068 * @element: a #GstElement to find a request pad of.
1069 * @templ: a #GstPadTemplate of which we want a pad of.
1070 * @name: (transfer none) (allow-none): the name of the request #GstPad
1071 * to retrieve. Can be %NULL.
1072 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1073 * request. Can be %NULL.
1075 * Retrieves a request pad from the element according to the provided template.
1076 * Pad templates can be looked up using
1077 * gst_element_factory_get_static_pad_templates().
1079 * The pad should be released with gst_element_release_request_pad().
1081 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1082 * 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);
1090 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1092 return _gst_element_request_pad (element, templ, name, caps);
1095 static GstIterator *
1096 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1098 GstIterator *result;
1100 GST_OBJECT_LOCK (element);
1101 result = gst_iterator_new_list (GST_TYPE_PAD,
1102 GST_OBJECT_GET_LOCK (element),
1103 &element->pads_cookie, padlist, (GObject *) element, NULL);
1104 GST_OBJECT_UNLOCK (element);
1110 * gst_element_iterate_pads:
1111 * @element: a #GstElement to iterate pads of.
1113 * Retrieves an iterator of @element's pads. The iterator should
1114 * be freed after usage. Also more specialized iterators exists such as
1115 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1117 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1123 gst_element_iterate_pads (GstElement * element)
1125 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1127 return gst_element_iterate_pad_list (element, &element->pads);
1131 * gst_element_iterate_src_pads:
1132 * @element: a #GstElement.
1134 * Retrieves an iterator of @element's source pads.
1136 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1142 gst_element_iterate_src_pads (GstElement * element)
1144 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1146 return gst_element_iterate_pad_list (element, &element->srcpads);
1150 * gst_element_iterate_sink_pads:
1151 * @element: a #GstElement.
1153 * Retrieves an iterator of @element's sink pads.
1155 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1161 gst_element_iterate_sink_pads (GstElement * element)
1163 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1165 return gst_element_iterate_pad_list (element, &element->sinkpads);
1169 * gst_element_class_add_pad_template:
1170 * @klass: the #GstElementClass to add the pad template to.
1171 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1173 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1174 * functions of classes. If a pad template with the same name as an already
1175 * existing one is added the old one is replaced by the new one.
1179 gst_element_class_add_pad_template (GstElementClass * klass,
1180 GstPadTemplate * templ)
1182 GList *template_list = klass->padtemplates;
1184 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1185 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1187 /* If we already have a pad template with the same name replace the
1189 while (template_list) {
1190 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1192 /* Found pad with the same name, replace and return */
1193 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1194 gst_object_unref (padtempl);
1195 template_list->data = templ;
1198 template_list = g_list_next (template_list);
1201 /* Take ownership of the floating ref */
1202 gst_object_ref_sink (templ);
1204 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1205 klass->numpadtemplates++;
1209 * gst_element_class_add_metadata:
1210 * @klass: class to set metadata for
1211 * @key: the key to set
1212 * @value: the value to set
1214 * Set @key with @value as metadata in @klass.
1217 gst_element_class_add_metadata (GstElementClass * klass,
1218 const gchar * key, const gchar * value)
1220 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1221 g_return_if_fail (key != NULL);
1222 g_return_if_fail (value != NULL);
1224 gst_structure_set ((GstStructure *) klass->metadata,
1225 key, G_TYPE_STRING, value, NULL);
1229 * gst_element_class_add_static_metadata:
1230 * @klass: class to set metadata for
1231 * @key: the key to set
1232 * @value: the value to set
1234 * Set @key with @value as metadata in @klass.
1236 * Same as gst_element_class_add_metadata(), but @value must be a static string
1237 * or an inlined string, as it will not be copied. (GStreamer plugins will
1238 * be made resident once loaded, so this function can be used even from
1239 * dynamically loaded plugins.)
1242 gst_element_class_add_static_metadata (GstElementClass * klass,
1243 const gchar * key, const gchar * value)
1245 GValue val = G_VALUE_INIT;
1247 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1248 g_return_if_fail (key != NULL);
1249 g_return_if_fail (value != NULL);
1251 g_value_init (&val, G_TYPE_STRING);
1252 g_value_set_static_string (&val, value);
1253 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1257 * gst_element_class_set_metadata:
1258 * @klass: class to set metadata for
1259 * @longname: The long English name of the element. E.g. "File Sink"
1260 * @classification: String describing the type of element, as an unordered list
1261 * separated with slashes ('/'). See draft-klass.txt of the design docs
1262 * for more details and common types. E.g: "Sink/File"
1263 * @description: Sentence describing the purpose of the element.
1264 * E.g: "Write stream to a file"
1265 * @author: Name and contact details of the author(s). Use \n to separate
1266 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1268 * Sets the detailed information for a #GstElementClass.
1269 * <note>This function is for use in _class_init functions only.</note>
1272 gst_element_class_set_metadata (GstElementClass * klass,
1273 const gchar * longname, const gchar * classification,
1274 const gchar * description, const gchar * author)
1276 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1278 gst_structure_id_set ((GstStructure *) klass->metadata,
1279 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1280 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1281 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1282 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1286 * gst_element_class_set_static_metadata:
1287 * @klass: class to set metadata for
1288 * @longname: The long English name of the element. E.g. "File Sink"
1289 * @classification: String describing the type of element, as an unordered list
1290 * separated with slashes ('/'). See draft-klass.txt of the design docs
1291 * for more details and common types. E.g: "Sink/File"
1292 * @description: Sentence describing the purpose of the element.
1293 * E.g: "Write stream to a file"
1294 * @author: Name and contact details of the author(s). Use \n to separate
1295 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1297 * Sets the detailed information for a #GstElementClass.
1298 * <note>This function is for use in _class_init functions only.</note>
1300 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1301 * @description, and @author must be static strings or inlined strings, as
1302 * they will not be copied. (GStreamer plugins will be made resident once
1303 * loaded, so this function can be used even from dynamically loaded plugins.)
1306 gst_element_class_set_static_metadata (GstElementClass * klass,
1307 const gchar * longname, const gchar * classification,
1308 const gchar * description, const gchar * author)
1310 GstStructure *s = (GstStructure *) klass->metadata;
1311 GValue val = G_VALUE_INIT;
1313 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1315 g_value_init (&val, G_TYPE_STRING);
1317 g_value_set_static_string (&val, longname);
1318 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1320 g_value_set_static_string (&val, classification);
1321 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1323 g_value_set_static_string (&val, description);
1324 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1327 g_value_set_static_string (&val, author);
1328 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1332 * gst_element_class_get_metadata:
1333 * @klass: class to get metadata for
1334 * @key: the key to get
1336 * Get metadata with @key in @klass.
1338 * Returns: the metadata for @key.
1341 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1343 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1344 g_return_val_if_fail (key != NULL, NULL);
1346 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1350 * gst_element_class_get_pad_template_list:
1351 * @element_class: a #GstElementClass to get pad templates of.
1353 * Retrieves a list of the pad templates associated with @element_class. The
1354 * list must not be modified by the calling code.
1355 * <note>If you use this function in the #GInstanceInitFunc of an object class
1356 * that has subclasses, make sure to pass the g_class parameter of the
1357 * #GInstanceInitFunc here.</note>
1359 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1363 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1365 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1367 return element_class->padtemplates;
1371 * gst_element_class_get_pad_template:
1372 * @element_class: a #GstElementClass to get the pad template of.
1373 * @name: the name of the #GstPadTemplate to get.
1375 * Retrieves a padtemplate from @element_class with the given name.
1376 * <note>If you use this function in the #GInstanceInitFunc of an object class
1377 * that has subclasses, make sure to pass the g_class parameter of the
1378 * #GInstanceInitFunc here.</note>
1380 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1381 * if none was found. No unreferencing is necessary.
1384 gst_element_class_get_pad_template (GstElementClass *
1385 element_class, const gchar * name)
1389 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1390 g_return_val_if_fail (name != NULL, NULL);
1392 padlist = element_class->padtemplates;
1395 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1397 if (strcmp (padtempl->name_template, name) == 0)
1400 padlist = g_list_next (padlist);
1406 static GstPadTemplate *
1407 gst_element_class_get_request_pad_template (GstElementClass *
1408 element_class, const gchar * name)
1410 GstPadTemplate *tmpl;
1412 tmpl = gst_element_class_get_pad_template (element_class, name);
1413 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1419 /* get a random pad on element of the given direction.
1420 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1423 gst_element_get_random_pad (GstElement * element,
1424 gboolean need_linked, GstPadDirection dir)
1426 GstPad *result = NULL;
1429 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1433 GST_OBJECT_LOCK (element);
1434 pads = element->srcpads;
1437 GST_OBJECT_LOCK (element);
1438 pads = element->sinkpads;
1441 goto wrong_direction;
1443 for (; pads; pads = g_list_next (pads)) {
1444 GstPad *pad = GST_PAD_CAST (pads->data);
1446 GST_OBJECT_LOCK (pad);
1447 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1448 GST_DEBUG_PAD_NAME (pad));
1450 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1451 /* if we require a linked pad, and it is not linked, continue the
1453 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1454 GST_DEBUG_PAD_NAME (pad));
1455 GST_OBJECT_UNLOCK (pad);
1458 /* found a pad, stop search */
1459 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1460 GST_DEBUG_PAD_NAME (pad));
1461 GST_OBJECT_UNLOCK (pad);
1467 gst_object_ref (result);
1469 GST_OBJECT_UNLOCK (element);
1473 /* ERROR handling */
1476 g_warning ("unknown pad direction %d", dir);
1482 gst_element_default_send_event (GstElement * element, GstEvent * event)
1484 gboolean result = FALSE;
1487 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1488 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1489 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1492 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1493 "pushing %s event to random %s pad %s:%s",
1494 GST_EVENT_TYPE_NAME (event),
1495 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1496 GST_DEBUG_PAD_NAME (pad));
1498 result = gst_pad_push_event (pad, event);
1499 gst_object_unref (pad);
1501 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1502 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1503 gst_event_unref (event);
1509 * gst_element_send_event:
1510 * @element: a #GstElement to send the event to.
1511 * @event: (transfer full): the #GstEvent to send to the element.
1513 * Sends an event to an element. If the element doesn't implement an
1514 * event handler, the event will be pushed on a random linked sink pad for
1515 * upstream events or a random linked source pad for downstream events.
1517 * This function takes owership of the provided event so you should
1518 * gst_event_ref() it if you want to reuse the event after this call.
1522 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1523 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1526 gst_element_send_event (GstElement * element, GstEvent * event)
1528 GstElementClass *oclass;
1529 gboolean result = FALSE;
1531 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1532 g_return_val_if_fail (event != NULL, FALSE);
1534 oclass = GST_ELEMENT_GET_CLASS (element);
1536 GST_STATE_LOCK (element);
1537 if (oclass->send_event) {
1538 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1539 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1540 result = oclass->send_event (element, event);
1542 GST_STATE_UNLOCK (element);
1549 * @element: a #GstElement to send the event to.
1550 * @rate: The new playback rate
1551 * @format: The format of the seek values
1552 * @flags: The optional seek flags.
1553 * @cur_type: The type and flags for the new current position
1554 * @cur: The value of the new current position
1555 * @stop_type: The type and flags for the new stop position
1556 * @stop: The value of the new stop position
1558 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1559 * the parameters. The seek event is sent to the element using
1560 * gst_element_send_event().
1564 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1565 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1568 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1569 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1570 GstSeekType stop_type, gint64 stop)
1575 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1578 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1579 result = gst_element_send_event (element, event);
1585 gst_element_default_query (GstElement * element, GstQuery * query)
1587 gboolean result = FALSE;
1590 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1592 result = gst_pad_query (pad, query);
1594 gst_object_unref (pad);
1596 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1598 GstPad *peer = gst_pad_get_peer (pad);
1601 result = gst_pad_query (peer, query);
1603 gst_object_unref (peer);
1605 gst_object_unref (pad);
1612 * gst_element_query:
1613 * @element: a #GstElement to perform the query on.
1614 * @query: (transfer none): the #GstQuery.
1616 * Performs a query on the given element.
1618 * For elements that don't implement a query handler, this function
1619 * forwards the query to a random srcpad or to the peer of a
1620 * random linked sinkpad of this element.
1622 * Please note that some queries might need a running pipeline to work.
1624 * Returns: TRUE if the query could be performed.
1629 gst_element_query (GstElement * element, GstQuery * query)
1631 GstElementClass *oclass;
1632 gboolean result = FALSE;
1634 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1635 g_return_val_if_fail (query != NULL, FALSE);
1637 oclass = GST_ELEMENT_GET_CLASS (element);
1639 if (oclass->query) {
1640 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1641 GST_ELEMENT_NAME (element));
1642 result = oclass->query (element, query);
1648 * gst_element_post_message:
1649 * @element: a #GstElement posting the message
1650 * @message: (transfer full): a #GstMessage to post
1652 * Post a message on the element's #GstBus. This function takes ownership of the
1653 * message; if you want to access the message after this call, you should add an
1654 * additional reference before calling.
1656 * Returns: %TRUE if the message was successfully posted. The function returns
1657 * %FALSE if the element did not have a bus.
1662 gst_element_post_message (GstElement * element, GstMessage * message)
1665 gboolean result = FALSE;
1667 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1668 g_return_val_if_fail (message != NULL, FALSE);
1670 GST_OBJECT_LOCK (element);
1673 if (G_UNLIKELY (bus == NULL))
1676 gst_object_ref (bus);
1677 GST_OBJECT_UNLOCK (element);
1679 /* we release the element lock when posting the message so that any
1680 * (synchronous) message handlers can operate on the element */
1681 result = gst_bus_post (bus, message);
1682 gst_object_unref (bus);
1689 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1690 "not posting message %p: no bus", message);
1691 GST_OBJECT_UNLOCK (element);
1692 gst_message_unref (message);
1698 * _gst_element_error_printf:
1699 * @format: the printf-like format to use, or %NULL
1701 * This function is only used internally by the gst_element_error() macro.
1703 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1709 _gst_element_error_printf (const gchar * format, ...)
1719 va_start (args, format);
1720 buffer = g_strdup_vprintf (format, args);
1726 * gst_element_message_full:
1727 * @element: a #GstElement to send message from
1728 * @type: the #GstMessageType
1729 * @domain: the GStreamer GError domain this message belongs to
1730 * @code: the GError code belonging to the domain
1731 * @text: (allow-none) (transfer full): an allocated text string to be used
1732 * as a replacement for the default message connected to code,
1734 * @debug: (allow-none) (transfer full): an allocated debug message to be
1735 * used as a replacement for the default debugging information,
1737 * @file: the source code file where the error was generated
1738 * @function: the source code function where the error was generated
1739 * @line: the source code line where the error was generated
1741 * Post an error, warning or info message on the bus from inside an element.
1743 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1744 * #GST_MESSAGE_INFO.
1748 void gst_element_message_full
1749 (GstElement * element, GstMessageType type,
1750 GQuark domain, gint code, gchar * text,
1751 gchar * debug, const gchar * file, const gchar * function, gint line)
1753 GError *gerror = NULL;
1757 gboolean has_debug = TRUE;
1758 GstMessage *message = NULL;
1761 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1762 g_return_if_fail (GST_IS_ELEMENT (element));
1763 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1764 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1766 /* check if we send the given text or the default error text */
1767 if ((text == NULL) || (text[0] == 0)) {
1768 /* text could have come from g_strdup_printf (""); */
1770 sent_text = gst_error_get_message (domain, code);
1774 /* construct a sent_debug with extra information from source */
1775 if ((debug == NULL) || (debug[0] == 0)) {
1776 /* debug could have come from g_strdup_printf (""); */
1780 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1782 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1783 file, line, function, name, debug);
1785 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1786 file, line, function, name);
1790 /* create gerror and post message */
1791 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1793 gerror = g_error_new_literal (domain, code, sent_text);
1796 case GST_MESSAGE_ERROR:
1798 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1800 case GST_MESSAGE_WARNING:
1801 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1804 case GST_MESSAGE_INFO:
1805 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1809 g_assert_not_reached ();
1812 gst_element_post_message (element, message);
1814 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1815 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1818 g_error_free (gerror);
1819 g_free (sent_debug);
1824 * gst_element_is_locked_state:
1825 * @element: a #GstElement.
1827 * Checks if the state of an element is locked.
1828 * If the state of an element is locked, state changes of the parent don't
1829 * affect the element.
1830 * This way you can leave currently unused elements inside bins. Just lock their
1831 * state before changing the state from #GST_STATE_NULL.
1835 * Returns: TRUE, if the element's state is locked.
1838 gst_element_is_locked_state (GstElement * element)
1842 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1844 GST_OBJECT_LOCK (element);
1845 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1846 GST_OBJECT_UNLOCK (element);
1852 * gst_element_set_locked_state:
1853 * @element: a #GstElement
1854 * @locked_state: TRUE to lock the element's state
1856 * Locks the state of an element, so state changes of the parent don't affect
1857 * this element anymore.
1861 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1862 * or the elements state-locking needed no change.
1865 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1869 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1871 GST_OBJECT_LOCK (element);
1872 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1874 if (G_UNLIKELY (old == locked_state))
1878 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1879 GST_ELEMENT_NAME (element));
1880 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1882 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1883 GST_ELEMENT_NAME (element));
1884 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1886 GST_OBJECT_UNLOCK (element);
1892 GST_CAT_DEBUG (GST_CAT_STATES,
1893 "elements %s was already in locked state %d",
1894 GST_ELEMENT_NAME (element), old);
1895 GST_OBJECT_UNLOCK (element);
1902 * gst_element_sync_state_with_parent:
1903 * @element: a #GstElement.
1905 * Tries to change the state of the element to the same as its parent.
1906 * If this function returns FALSE, the state of element is undefined.
1908 * Returns: TRUE, if the element's state could be synced to the parent's state.
1913 gst_element_sync_state_with_parent (GstElement * element)
1917 GstStateChangeReturn ret;
1919 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1921 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1922 GstState parent_current, parent_pending;
1924 GST_OBJECT_LOCK (parent);
1925 parent_current = GST_STATE (parent);
1926 parent_pending = GST_STATE_PENDING (parent);
1927 GST_OBJECT_UNLOCK (parent);
1929 /* set to pending if there is one, else we set it to the current state of
1931 if (parent_pending != GST_STATE_VOID_PENDING)
1932 target = parent_pending;
1934 target = parent_current;
1936 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1937 "syncing state (%s) to parent %s %s (%s, %s)",
1938 gst_element_state_get_name (GST_STATE (element)),
1939 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1940 gst_element_state_get_name (parent_current),
1941 gst_element_state_get_name (parent_pending));
1943 ret = gst_element_set_state (element, target);
1944 if (ret == GST_STATE_CHANGE_FAILURE)
1947 gst_object_unref (parent);
1951 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1958 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1959 "syncing state failed (%s)",
1960 gst_element_state_change_return_get_name (ret));
1961 gst_object_unref (parent);
1967 static GstStateChangeReturn
1968 gst_element_get_state_func (GstElement * element,
1969 GstState * state, GstState * pending, GstClockTime timeout)
1971 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1972 GstState old_pending;
1974 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1975 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1977 GST_OBJECT_LOCK (element);
1978 ret = GST_STATE_RETURN (element);
1979 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1980 gst_element_state_change_return_get_name (ret));
1982 /* we got an error, report immediately */
1983 if (ret == GST_STATE_CHANGE_FAILURE)
1986 /* we got no_preroll, report immediately */
1987 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1990 /* no need to wait async if we are not async */
1991 if (ret != GST_STATE_CHANGE_ASYNC)
1994 old_pending = GST_STATE_PENDING (element);
1995 if (old_pending != GST_STATE_VOID_PENDING) {
1999 /* get cookie to detect state changes during waiting */
2000 cookie = element->state_cookie;
2002 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2003 "waiting for element to commit state");
2005 /* we have a pending state change, wait for it to complete */
2006 if (timeout != GST_CLOCK_TIME_NONE) {
2008 /* make timeout absolute */
2009 end_time = g_get_monotonic_time () + (timeout / 1000);
2010 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2012 GST_STATE_WAIT (element);
2017 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2018 /* timeout triggered */
2019 ret = GST_STATE_CHANGE_ASYNC;
2021 if (cookie != element->state_cookie)
2024 /* could be success or failure */
2025 if (old_pending == GST_STATE (element)) {
2026 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2027 ret = GST_STATE_CHANGE_SUCCESS;
2029 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2030 ret = GST_STATE_CHANGE_FAILURE;
2033 /* if nothing is pending anymore we can return SUCCESS */
2034 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2035 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2036 ret = GST_STATE_CHANGE_SUCCESS;
2042 *state = GST_STATE (element);
2044 *pending = GST_STATE_PENDING (element);
2046 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2047 "state current: %s, pending: %s, result: %s",
2048 gst_element_state_get_name (GST_STATE (element)),
2049 gst_element_state_get_name (GST_STATE_PENDING (element)),
2050 gst_element_state_change_return_get_name (ret));
2051 GST_OBJECT_UNLOCK (element);
2058 *state = GST_STATE_VOID_PENDING;
2060 *pending = GST_STATE_VOID_PENDING;
2062 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2064 GST_OBJECT_UNLOCK (element);
2066 return GST_STATE_CHANGE_FAILURE;
2071 * gst_element_get_state:
2072 * @element: a #GstElement to get the state of.
2073 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2075 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2076 * state. Can be %NULL.
2077 * @timeout: a #GstClockTime to specify the timeout for an async
2078 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2080 * Gets the state of the element.
2082 * For elements that performed an ASYNC state change, as reported by
2083 * gst_element_set_state(), this function will block up to the
2084 * specified timeout value for the state change to complete.
2085 * If the element completes the state change or goes into
2086 * an error, this function returns immediately with a return value of
2087 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2089 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2090 * returns the current and pending state immediately.
2092 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2093 * successfully changed its state but is not able to provide data yet.
2094 * This mostly happens for live sources that only produce data in
2095 * %GST_STATE_PLAYING. While the state change return is equivalent to
2096 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2097 * some sink elements might not be able to complete their state change because
2098 * an element is not producing data to complete the preroll. When setting the
2099 * element to playing, the preroll will complete and playback will start.
2101 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2102 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2103 * element is still performing a state change or
2104 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2108 GstStateChangeReturn
2109 gst_element_get_state (GstElement * element,
2110 GstState * state, GstState * pending, GstClockTime timeout)
2112 GstElementClass *oclass;
2113 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2115 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2117 oclass = GST_ELEMENT_GET_CLASS (element);
2119 if (oclass->get_state)
2120 result = (oclass->get_state) (element, state, pending, timeout);
2126 * gst_element_abort_state:
2127 * @element: a #GstElement to abort the state of.
2129 * Abort the state change of the element. This function is used
2130 * by elements that do asynchronous state changes and find out
2131 * something is wrong.
2133 * This function should be called with the STATE_LOCK held.
2138 gst_element_abort_state (GstElement * element)
2142 #ifndef GST_DISABLE_GST_DEBUG
2146 g_return_if_fail (GST_IS_ELEMENT (element));
2148 GST_OBJECT_LOCK (element);
2149 pending = GST_STATE_PENDING (element);
2151 if (pending == GST_STATE_VOID_PENDING ||
2152 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2153 goto nothing_aborted;
2155 #ifndef GST_DISABLE_GST_DEBUG
2156 old_state = GST_STATE (element);
2158 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2159 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2160 gst_element_state_get_name (pending));
2164 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2166 GST_STATE_BROADCAST (element);
2167 GST_OBJECT_UNLOCK (element);
2173 GST_OBJECT_UNLOCK (element);
2178 /* Not static because GstBin has manual state handling too */
2180 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2181 GstState newstate, GstState pending)
2183 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2184 GstMessage *message;
2186 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2187 "notifying about state-changed %s to %s (%s pending)",
2188 gst_element_state_get_name (oldstate),
2189 gst_element_state_get_name (newstate),
2190 gst_element_state_get_name (pending));
2192 if (klass->state_changed)
2193 klass->state_changed (element, oldstate, newstate, pending);
2195 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2196 oldstate, newstate, pending);
2197 gst_element_post_message (element, message);
2201 * gst_element_continue_state:
2202 * @element: a #GstElement to continue the state change of.
2203 * @ret: The previous state return value
2205 * Commit the state change of the element and proceed to the next
2206 * pending state if any. This function is used
2207 * by elements that do asynchronous state changes.
2208 * The core will normally call this method automatically when an
2209 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2211 * If after calling this method the element still has not reached
2212 * the pending state, the next state change is performed.
2214 * This method is used internally and should normally not be called by plugins
2217 * Returns: The result of the commit state change.
2221 GstStateChangeReturn
2222 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2224 GstStateChangeReturn old_ret;
2225 GstState old_state, old_next;
2226 GstState current, next, pending;
2227 GstStateChange transition;
2229 GST_OBJECT_LOCK (element);
2230 old_ret = GST_STATE_RETURN (element);
2231 GST_STATE_RETURN (element) = ret;
2232 pending = GST_STATE_PENDING (element);
2234 /* check if there is something to commit */
2235 if (pending == GST_STATE_VOID_PENDING)
2236 goto nothing_pending;
2238 old_state = GST_STATE (element);
2239 /* this is the state we should go to next */
2240 old_next = GST_STATE_NEXT (element);
2241 /* update current state */
2242 current = GST_STATE (element) = old_next;
2244 /* see if we reached the final state */
2245 if (pending == current)
2248 next = GST_STATE_GET_NEXT (current, pending);
2249 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2251 GST_STATE_NEXT (element) = next;
2253 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2254 GST_OBJECT_UNLOCK (element);
2256 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2257 "committing state from %s to %s, pending %s, next %s",
2258 gst_element_state_get_name (old_state),
2259 gst_element_state_get_name (old_next),
2260 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2262 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2264 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2265 "continue state change %s to %s, final %s",
2266 gst_element_state_get_name (current),
2267 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2269 ret = gst_element_change_state (element, transition);
2275 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2276 GST_OBJECT_UNLOCK (element);
2281 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2282 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2284 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2285 "completed state change to %s", gst_element_state_get_name (pending));
2286 GST_OBJECT_UNLOCK (element);
2288 /* don't post silly messages with the same state. This can happen
2289 * when an element state is changed to what it already was. For bins
2290 * this can be the result of a lost state, which we check with the
2291 * previous return value.
2292 * We do signal the cond though as a _get_state() might be blocking
2294 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2295 _priv_gst_element_state_changed (element, old_state, old_next,
2296 GST_STATE_VOID_PENDING);
2298 GST_STATE_BROADCAST (element);
2305 * gst_element_lost_state:
2306 * @element: a #GstElement the state is lost of
2308 * Brings the element to the lost state. The current state of the
2309 * element is copied to the pending state so that any call to
2310 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2312 * An ASYNC_START message is posted. If the element was PLAYING, it will
2313 * go to PAUSED. The element will be restored to its PLAYING state by
2314 * the parent pipeline when it prerolls again.
2316 * This is mostly used for elements that lost their preroll buffer
2317 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2318 * they will go to their pending state again when a new preroll buffer is
2319 * queued. This function can only be called when the element is currently
2320 * not in error or an async state change.
2322 * This function is used internally and should normally not be called from
2323 * plugins or applications.
2326 gst_element_lost_state (GstElement * element)
2328 GstState old_state, new_state;
2329 GstMessage *message;
2331 g_return_if_fail (GST_IS_ELEMENT (element));
2333 GST_OBJECT_LOCK (element);
2334 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2337 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2338 goto only_async_start;
2340 old_state = GST_STATE (element);
2342 /* when we were PLAYING, the new state is PAUSED. We will also not
2343 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2344 * when we preroll. */
2345 if (old_state > GST_STATE_PAUSED)
2346 new_state = GST_STATE_PAUSED;
2348 new_state = old_state;
2350 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2351 "lost state of %s to %s", gst_element_state_get_name (old_state),
2352 gst_element_state_get_name (new_state));
2354 GST_STATE (element) = new_state;
2355 GST_STATE_NEXT (element) = new_state;
2356 GST_STATE_PENDING (element) = new_state;
2357 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2358 GST_OBJECT_UNLOCK (element);
2360 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2362 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2363 gst_element_post_message (element, message);
2369 GST_OBJECT_UNLOCK (element);
2374 GST_OBJECT_UNLOCK (element);
2376 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2377 gst_element_post_message (element, message);
2383 * gst_element_set_state:
2384 * @element: a #GstElement to change state of.
2385 * @state: the element's new #GstState.
2387 * Sets the state of the element. This function will try to set the
2388 * requested state by going through all the intermediary states and calling
2389 * the class's state change function for each.
2391 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2392 * element will perform the remainder of the state change asynchronously in
2394 * An application can use gst_element_get_state() to wait for the completion
2395 * of the state change or it can wait for a state change message on the bus.
2397 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2398 * #GST_STATE_CHANGE_ASYNC.
2400 * Returns: Result of the state change using #GstStateChangeReturn.
2404 GstStateChangeReturn
2405 gst_element_set_state (GstElement * element, GstState state)
2407 GstElementClass *oclass;
2408 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2410 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2412 oclass = GST_ELEMENT_GET_CLASS (element);
2414 if (oclass->set_state)
2415 result = (oclass->set_state) (element, state);
2421 * default set state function, calculates the next state based
2422 * on current state and calls the change_state function
2424 static GstStateChangeReturn
2425 gst_element_set_state_func (GstElement * element, GstState state)
2427 GstState current, next, old_pending;
2428 GstStateChangeReturn ret;
2429 GstStateChange transition;
2430 GstStateChangeReturn old_ret;
2432 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2434 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2435 gst_element_state_get_name (state));
2437 /* state lock is taken to protect the set_state() and get_state()
2438 * procedures, it does not lock any variables. */
2439 GST_STATE_LOCK (element);
2441 /* now calculate how to get to the new state */
2442 GST_OBJECT_LOCK (element);
2443 old_ret = GST_STATE_RETURN (element);
2444 /* previous state change returned an error, remove all pending
2445 * and next states */
2446 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2447 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2448 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2449 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2452 current = GST_STATE (element);
2453 next = GST_STATE_NEXT (element);
2454 old_pending = GST_STATE_PENDING (element);
2456 /* this is the (new) state we should go to. TARGET is the last state we set on
2458 if (state != GST_STATE_TARGET (element)) {
2459 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2460 "setting target state to %s", gst_element_state_get_name (state));
2461 GST_STATE_TARGET (element) = state;
2462 /* increment state cookie so that we can track each state change. We only do
2463 * this if this is actually a new state change. */
2464 element->state_cookie++;
2466 GST_STATE_PENDING (element) = state;
2468 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2469 "current %s, old_pending %s, next %s, old return %s",
2470 gst_element_state_get_name (current),
2471 gst_element_state_get_name (old_pending),
2472 gst_element_state_get_name (next),
2473 gst_element_state_change_return_get_name (old_ret));
2475 /* if the element was busy doing a state change, we just update the
2476 * target state, it'll get to it async then. */
2477 if (old_pending != GST_STATE_VOID_PENDING) {
2478 /* upwards state change will happen ASYNC */
2479 if (old_pending <= state)
2481 /* element is going to this state already */
2482 else if (next == state)
2484 /* element was performing an ASYNC upward state change and
2485 * we request to go downward again. Start from the next pending
2487 else if (next > state
2488 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2492 next = GST_STATE_GET_NEXT (current, state);
2493 /* now we store the next state */
2494 GST_STATE_NEXT (element) = next;
2495 /* mark busy, we need to check that there is actually a state change
2496 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2497 * the default element change_state function has no way to know what the
2498 * old value was... could consider this a FIXME...*/
2499 if (current != next)
2500 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2502 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2504 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2505 "%s: setting state from %s to %s",
2506 (next != state ? "intermediate" : "final"),
2507 gst_element_state_get_name (current), gst_element_state_get_name (next));
2509 /* now signal any waiters, they will error since the cookie was incremented */
2510 GST_STATE_BROADCAST (element);
2512 GST_OBJECT_UNLOCK (element);
2514 ret = gst_element_change_state (element, transition);
2516 GST_STATE_UNLOCK (element);
2518 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2519 gst_element_state_change_return_get_name (ret));
2525 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2526 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2527 "element was busy with async state change");
2528 GST_OBJECT_UNLOCK (element);
2530 GST_STATE_UNLOCK (element);
2532 return GST_STATE_CHANGE_ASYNC;
2537 * gst_element_change_state:
2538 * @element: a #GstElement
2539 * @transition: the requested transition
2541 * Perform @transition on @element.
2543 * This function must be called with STATE_LOCK held and is mainly used
2546 * Returns: the #GstStateChangeReturn of the state transition.
2548 GstStateChangeReturn
2549 gst_element_change_state (GstElement * element, GstStateChange transition)
2551 GstElementClass *oclass;
2552 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2554 oclass = GST_ELEMENT_GET_CLASS (element);
2556 /* call the state change function so it can set the state */
2557 if (oclass->change_state)
2558 ret = (oclass->change_state) (element, transition);
2560 ret = GST_STATE_CHANGE_FAILURE;
2563 case GST_STATE_CHANGE_FAILURE:
2564 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2565 "have FAILURE change_state return");
2566 /* state change failure */
2567 gst_element_abort_state (element);
2569 case GST_STATE_CHANGE_ASYNC:
2573 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2574 "element will change state ASYNC");
2576 target = GST_STATE_TARGET (element);
2578 if (target > GST_STATE_READY)
2581 /* else we just continue the state change downwards */
2582 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2583 "forcing commit state %s <= %s",
2584 gst_element_state_get_name (target),
2585 gst_element_state_get_name (GST_STATE_READY));
2587 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2590 case GST_STATE_CHANGE_SUCCESS:
2591 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2592 "element changed state SUCCESS");
2593 /* we can commit the state now which will proceeed to
2595 ret = gst_element_continue_state (element, ret);
2597 case GST_STATE_CHANGE_NO_PREROLL:
2598 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2599 "element changed state NO_PREROLL");
2600 /* we can commit the state now which will proceeed to
2602 ret = gst_element_continue_state (element, ret);
2605 goto invalid_return;
2608 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2613 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2621 GST_OBJECT_LOCK (element);
2622 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2623 g_critical ("%s: unknown return value %d from a state change function",
2624 GST_ELEMENT_NAME (element), ret);
2626 /* we are in error now */
2627 ret = GST_STATE_CHANGE_FAILURE;
2628 GST_STATE_RETURN (element) = ret;
2629 GST_OBJECT_UNLOCK (element);
2635 /* gst_iterator_fold functions for pads_activate
2636 * Stop the iterator if activating one pad failed. */
2638 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2640 GstPad *pad = g_value_get_object (vpad);
2641 gboolean cont = TRUE;
2643 if (!(cont = gst_pad_set_active (pad, *active)))
2644 g_value_set_boolean (ret, FALSE);
2649 /* returns false on error or early cutout of the fold, true if all
2650 * pads in @iter were (de)activated successfully. */
2652 iterator_activate_fold_with_resync (GstIterator * iter,
2653 GstIteratorFoldFunction func, gpointer user_data)
2655 GstIteratorResult ires;
2658 /* no need to unset this later, it's just a boolean */
2659 g_value_init (&ret, G_TYPE_BOOLEAN);
2660 g_value_set_boolean (&ret, TRUE);
2663 ires = gst_iterator_fold (iter, func, &ret, user_data);
2665 case GST_ITERATOR_RESYNC:
2666 /* need to reset the result again */
2667 g_value_set_boolean (&ret, TRUE);
2668 gst_iterator_resync (iter);
2670 case GST_ITERATOR_DONE:
2671 /* all pads iterated, return collected value */
2674 /* iterator returned _ERROR or premature end with _OK,
2675 * mark an error and exit */
2676 g_value_set_boolean (&ret, FALSE);
2681 /* return collected value */
2682 return g_value_get_boolean (&ret);
2685 /* is called with STATE_LOCK
2687 * Pads are activated from source pads to sinkpads.
2690 gst_element_pads_activate (GstElement * element, gboolean active)
2695 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2696 "%s pads", active ? "activate" : "deactivate");
2698 iter = gst_element_iterate_src_pads (element);
2700 iterator_activate_fold_with_resync (iter,
2701 (GstIteratorFoldFunction) activate_pads, &active);
2702 gst_iterator_free (iter);
2703 if (G_UNLIKELY (!res))
2706 iter = gst_element_iterate_sink_pads (element);
2708 iterator_activate_fold_with_resync (iter,
2709 (GstIteratorFoldFunction) activate_pads, &active);
2710 gst_iterator_free (iter);
2711 if (G_UNLIKELY (!res))
2714 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2715 "pad %sactivation successful", active ? "" : "de");
2722 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2723 "pad %sactivation failed", active ? "" : "de");
2728 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2729 "sink pads_activate failed");
2734 /* is called with STATE_LOCK */
2735 static GstStateChangeReturn
2736 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2738 GstState state, next;
2739 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2741 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2743 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2744 next = GST_STATE_TRANSITION_NEXT (transition);
2746 /* if the element already is in the given state, we just return success */
2747 if (next == GST_STATE_VOID_PENDING || state == next)
2750 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2751 "default handler tries setting state from %s to %s (%04x)",
2752 gst_element_state_get_name (state),
2753 gst_element_state_get_name (next), transition);
2755 switch (transition) {
2756 case GST_STATE_CHANGE_NULL_TO_READY:
2758 case GST_STATE_CHANGE_READY_TO_PAUSED:
2759 if (!gst_element_pads_activate (element, TRUE)) {
2760 result = GST_STATE_CHANGE_FAILURE;
2763 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2765 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2767 case GST_STATE_CHANGE_PAUSED_TO_READY:
2768 case GST_STATE_CHANGE_READY_TO_NULL:
2769 /* deactivate pads in both cases, since they are activated on
2770 ready->paused but the element might not have made it to paused */
2771 if (!gst_element_pads_activate (element, FALSE)) {
2772 result = GST_STATE_CHANGE_FAILURE;
2776 /* this will catch real but unhandled state changes;
2777 * can only be caused by:
2778 * - a new state was added
2779 * - somehow the element was asked to jump across an intermediate state
2781 g_warning ("Unhandled state change from %s to %s",
2782 gst_element_state_get_name (state),
2783 gst_element_state_get_name (next));
2790 GST_OBJECT_LOCK (element);
2791 result = GST_STATE_RETURN (element);
2792 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2793 "element is already in the %s state",
2794 gst_element_state_get_name (state));
2795 GST_OBJECT_UNLOCK (element);
2802 * gst_element_get_factory:
2803 * @element: a #GstElement to request the element factory of.
2805 * Retrieves the factory that was used to create this element.
2807 * Returns: (transfer none): the #GstElementFactory used for creating this
2808 * element. no refcounting is needed.
2811 gst_element_get_factory (GstElement * element)
2813 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2815 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2819 gst_element_dispose (GObject * object)
2821 GstElement *element = GST_ELEMENT_CAST (object);
2824 GstElementClass *oclass;
2827 oclass = GST_ELEMENT_GET_CLASS (element);
2829 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2831 if (GST_STATE (element) != GST_STATE_NULL)
2834 /* start by releasing all request pads, this might also remove some dynamic
2836 walk = element->pads;
2838 GstPad *pad = GST_PAD_CAST (walk->data);
2842 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
2843 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
2844 == GST_PAD_REQUEST) {
2845 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2846 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2847 oclass->release_pad (element, pad);
2849 /* in case the release_pad function removed the next pad too */
2850 if (walk && g_list_position (element->pads, walk) == -1)
2851 walk = element->pads;
2854 /* remove the remaining pads */
2855 while (element->pads) {
2856 GstPad *pad = GST_PAD_CAST (element->pads->data);
2857 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2858 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2859 if (!gst_element_remove_pad (element, pad)) {
2860 /* only happens when someone unparented our pad.. */
2861 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2866 GST_OBJECT_LOCK (element);
2867 clock_p = &element->clock;
2868 bus_p = &element->bus;
2869 gst_object_replace ((GstObject **) clock_p, NULL);
2870 gst_object_replace ((GstObject **) bus_p, NULL);
2871 GST_OBJECT_UNLOCK (element);
2873 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2875 G_OBJECT_CLASS (parent_class)->dispose (object);
2884 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2886 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2888 "You need to explicitly set elements to the NULL state before\n"
2889 "dropping the final reference, to allow them to clean up.\n"
2890 "This problem may also be caused by a refcounting bug in the\n"
2891 "application or some element.\n",
2892 GST_OBJECT_NAME (element),
2893 gst_element_state_get_name (GST_STATE (element)),
2894 is_locked ? " (locked)" : "");
2900 gst_element_finalize (GObject * object)
2902 GstElement *element = GST_ELEMENT_CAST (object);
2904 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2906 g_cond_clear (&element->state_cond);
2907 g_rec_mutex_clear (&element->state_lock);
2909 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2911 G_OBJECT_CLASS (parent_class)->finalize (object);
2915 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2919 g_return_if_fail (GST_IS_ELEMENT (element));
2921 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2923 GST_OBJECT_LOCK (element);
2924 bus_p = &GST_ELEMENT_BUS (element);
2925 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2926 GST_OBJECT_UNLOCK (element);
2930 * gst_element_set_bus:
2931 * @element: a #GstElement to set the bus of.
2932 * @bus: (transfer none): the #GstBus to set.
2934 * Sets the bus of the element. Increases the refcount on the bus.
2935 * For internal use only, unless you're testing elements.
2940 gst_element_set_bus (GstElement * element, GstBus * bus)
2942 GstElementClass *oclass;
2944 g_return_if_fail (GST_IS_ELEMENT (element));
2946 oclass = GST_ELEMENT_GET_CLASS (element);
2948 if (oclass->set_bus)
2949 oclass->set_bus (element, bus);
2953 * gst_element_get_bus:
2954 * @element: a #GstElement to get the bus of.
2956 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2957 * bus for the application.
2959 * Returns: (transfer full): the element's #GstBus. unref after usage.
2964 gst_element_get_bus (GstElement * element)
2966 GstBus *result = NULL;
2968 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2970 GST_OBJECT_LOCK (element);
2971 if ((result = GST_ELEMENT_BUS (element)))
2972 gst_object_ref (result);
2973 GST_OBJECT_UNLOCK (element);
2975 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,