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., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, 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.
47 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
49 * Elements can be linked through their pads.
50 * If the link is straightforward, use the gst_element_link()
51 * convenience function to link two elements, or gst_element_link_many()
52 * for more elements in a row.
53 * Use gst_element_link_filtered() to link two elements constrained by
54 * a specified set of #GstCaps.
55 * For finer control, use gst_element_link_pads() and
56 * gst_element_link_pads_filtered() to specify the pads to link on
57 * each element by name.
59 * Each element has a state (see #GstState). You can get and set the state
60 * of an element with gst_element_get_state() and gst_element_set_state().
61 * Setting a state triggers a #GstStateChange. To get a string representation
62 * of a #GstState, use gst_element_state_get_name().
64 * You can get and set a #GstClock on an element using gst_element_get_clock()
65 * and gst_element_set_clock().
66 * Some elements can provide a clock for the pipeline if
67 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the
68 * gst_element_provide_clock() method one can retrieve the clock provided by
70 * Not all elements require a clock to operate correctly. If the
71 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
72 * element with gst_element_set_clock().
74 * Note that clock selection and distribution is normally handled by the
75 * toplevel #GstPipeline so the clock functions are only to be used in very
76 * specific situations.
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstelementmetadata.h"
86 #include "gstenumtypes.h"
93 #include "gsttracerutils.h"
95 #include "gst-i18n-lib.h"
96 #include "glib-compat-private.h"
98 #ifndef GST_DISABLE_GST_DEBUG
99 #include "printf/printf.h"
102 /* Element signals and args */
118 static void gst_element_class_init (GstElementClass * klass);
119 static void gst_element_init (GstElement * element);
120 static void gst_element_base_class_init (gpointer g_class);
122 static void gst_element_constructed (GObject * object);
123 static void gst_element_dispose (GObject * object);
124 static void gst_element_finalize (GObject * object);
126 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
127 GstStateChange transition);
128 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
129 GstState * state, GstState * pending, GstClockTime timeout);
130 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
132 static gboolean gst_element_set_clock_func (GstElement * element,
134 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
135 static gboolean gst_element_post_message_default (GstElement * element,
136 GstMessage * message);
137 static void gst_element_set_context_default (GstElement * element,
138 GstContext * context);
140 static gboolean gst_element_default_send_event (GstElement * element,
142 static gboolean gst_element_default_query (GstElement * element,
145 static GstPadTemplate
146 * gst_element_class_get_request_pad_template (GstElementClass *
147 element_class, const gchar * name);
149 static void gst_element_call_async_func (gpointer data, gpointer user_data);
151 static GstObjectClass *parent_class = NULL;
152 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
154 static GThreadPool *gst_element_pool = NULL;
156 /* this is used in gstelementfactory.c:gst_element_register() */
157 GQuark __gst_elementclass_factory = 0;
160 gst_element_get_type (void)
162 static volatile gsize gst_element_type = 0;
164 if (g_once_init_enter (&gst_element_type)) {
166 static const GTypeInfo element_info = {
167 sizeof (GstElementClass),
168 gst_element_base_class_init,
169 NULL, /* base_class_finalize */
170 (GClassInitFunc) gst_element_class_init,
175 (GInstanceInitFunc) gst_element_init,
179 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
180 &element_info, G_TYPE_FLAG_ABSTRACT);
182 __gst_elementclass_factory =
183 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
184 g_once_init_leave (&gst_element_type, _type);
186 return gst_element_type;
190 gst_element_setup_thread_pool (void)
194 GST_DEBUG ("creating element thread pool");
196 g_thread_pool_new ((GFunc) gst_element_call_async_func, NULL, -1, FALSE,
199 g_critical ("could not alloc threadpool %s", err->message);
200 g_clear_error (&err);
205 gst_element_class_init (GstElementClass * klass)
207 GObjectClass *gobject_class;
209 gobject_class = (GObjectClass *) klass;
211 parent_class = g_type_class_peek_parent (klass);
214 * GstElement::pad-added:
215 * @gstelement: the object which received the signal
216 * @new_pad: the pad that has been added
218 * a new #GstPad has been added to the element. Note that this signal will
219 * usually be emitted from the context of the streaming thread. Also keep in
220 * mind that if you add new elements to the pipeline in the signal handler
221 * you will need to set them to the desired target state with
222 * gst_element_set_state() or gst_element_sync_state_with_parent().
224 gst_element_signals[PAD_ADDED] =
225 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
226 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
227 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
229 * GstElement::pad-removed:
230 * @gstelement: the object which received the signal
231 * @old_pad: the pad that has been removed
233 * a #GstPad has been removed from the element
235 gst_element_signals[PAD_REMOVED] =
236 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
237 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
238 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
240 * GstElement::no-more-pads:
241 * @gstelement: the object which received the signal
243 * This signals that the element will not generate more dynamic pads.
244 * Note that this signal will usually be emitted from the context of
245 * the streaming thread.
247 gst_element_signals[NO_MORE_PADS] =
248 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
249 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
250 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
252 gobject_class->dispose = gst_element_dispose;
253 gobject_class->finalize = gst_element_finalize;
254 gobject_class->constructed = gst_element_constructed;
256 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
257 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
258 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
259 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
260 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
261 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
262 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
263 klass->numpadtemplates = 0;
264 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
265 klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_default);
267 klass->elementfactory = NULL;
269 gst_element_setup_thread_pool ();
273 gst_element_base_class_init (gpointer g_class)
275 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
276 GList *node, *padtemplates;
278 /* Copy the element details here so elements can inherit the
279 * details from their base class and classes only need to set
280 * the details in class_init instead of base_init */
281 element_class->metadata =
282 element_class->metadata ? gst_structure_copy (element_class->metadata) :
283 gst_structure_new_empty ("metadata");
285 /* Copy the pad templates so elements inherit them
286 * from their base class but elements can add pad templates in class_init
287 * instead of base_init.
289 padtemplates = g_list_copy (element_class->padtemplates);
290 for (node = padtemplates; node != NULL; node = node->next) {
291 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
292 gst_object_ref (tmpl);
294 element_class->padtemplates = padtemplates;
296 /* set the factory, see gst_element_register() */
297 element_class->elementfactory =
298 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
299 __gst_elementclass_factory);
300 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
301 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
305 gst_element_init (GstElement * element)
307 GST_STATE (element) = GST_STATE_NULL;
308 GST_STATE_TARGET (element) = GST_STATE_NULL;
309 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
310 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
311 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
313 g_rec_mutex_init (&element->state_lock);
314 g_cond_init (&element->state_cond);
318 gst_element_constructed (GObject * object)
320 GST_TRACER_ELEMENT_NEW (GST_ELEMENT_CAST (object));
321 G_OBJECT_CLASS (parent_class)->constructed (object);
325 * gst_element_release_request_pad:
326 * @element: a #GstElement to release the request pad of.
327 * @pad: the #GstPad to release.
329 * Makes the element free the previously requested pad as obtained
330 * with gst_element_request_pad().
332 * This does not unref the pad. If the pad was created by using
333 * gst_element_request_pad(), gst_element_release_request_pad() needs to be
334 * followed by gst_object_unref() to free the @pad.
339 gst_element_release_request_pad (GstElement * element, GstPad * pad)
341 GstElementClass *oclass;
343 g_return_if_fail (GST_IS_ELEMENT (element));
344 g_return_if_fail (GST_IS_PAD (pad));
345 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
346 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
349 oclass = GST_ELEMENT_GET_CLASS (element);
351 /* if the element implements a custom release function we call that, else we
352 * simply remove the pad from the element */
353 if (oclass->release_pad)
354 oclass->release_pad (element, pad);
356 gst_element_remove_pad (element, pad);
360 * gst_element_provide_clock:
361 * @element: a #GstElement to query
363 * Get the clock provided by the given element.
364 * <note>An element is only required to provide a clock in the PAUSED
365 * state. Some elements can provide a clock in other states.</note>
367 * Returns: (transfer full) (nullable): the GstClock provided by the
368 * element or %NULL if no clock could be provided. Unref after usage.
373 gst_element_provide_clock (GstElement * element)
375 GstClock *result = NULL;
376 GstElementClass *oclass;
378 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
380 oclass = GST_ELEMENT_GET_CLASS (element);
382 if (oclass->provide_clock)
383 result = oclass->provide_clock (element);
389 gst_element_set_clock_func (GstElement * element, GstClock * clock)
393 GST_OBJECT_LOCK (element);
394 clock_p = &element->clock;
395 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
396 GST_OBJECT_UNLOCK (element);
402 * gst_element_set_clock:
403 * @element: a #GstElement to set the clock for.
404 * @clock: the #GstClock to set for the element.
406 * Sets the clock for the element. This function increases the
407 * refcount on the clock. Any previously set clock on the object
410 * Returns: %TRUE if the element accepted the clock. An element can refuse a
411 * clock when it, for example, is not able to slave its internal clock to the
412 * @clock or when it requires a specific clock to operate.
417 gst_element_set_clock (GstElement * element, GstClock * clock)
419 GstElementClass *oclass;
420 gboolean res = FALSE;
422 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
423 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
425 oclass = GST_ELEMENT_GET_CLASS (element);
427 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
429 if (oclass->set_clock)
430 res = oclass->set_clock (element, clock);
436 * gst_element_get_clock:
437 * @element: a #GstElement to get the clock of.
439 * Gets the currently configured clock of the element. This is the clock as was
440 * last set with gst_element_set_clock().
442 * Elements in a pipeline will only have their clock set when the
443 * pipeline is in the PLAYING state.
445 * Returns: (transfer full): the #GstClock of the element. unref after usage.
450 gst_element_get_clock (GstElement * element)
454 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
456 GST_OBJECT_LOCK (element);
457 if ((result = element->clock))
458 gst_object_ref (result);
459 GST_OBJECT_UNLOCK (element);
465 * gst_element_set_base_time:
466 * @element: a #GstElement.
467 * @time: the base time to set.
469 * Set the base time of an element. See gst_element_get_base_time().
474 gst_element_set_base_time (GstElement * element, GstClockTime time)
478 g_return_if_fail (GST_IS_ELEMENT (element));
480 GST_OBJECT_LOCK (element);
481 old = element->base_time;
482 element->base_time = time;
483 GST_OBJECT_UNLOCK (element);
485 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
486 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
487 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
491 * gst_element_get_base_time:
492 * @element: a #GstElement.
494 * Returns the base time of the element. The base time is the
495 * absolute time of the clock when this element was last put to
496 * PLAYING. Subtracting the base time from the clock time gives
497 * the running time of the element.
499 * Returns: the base time of the element.
504 gst_element_get_base_time (GstElement * element)
508 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
510 GST_OBJECT_LOCK (element);
511 result = element->base_time;
512 GST_OBJECT_UNLOCK (element);
518 * gst_element_set_start_time:
519 * @element: a #GstElement.
520 * @time: the base time to set.
522 * Set the start time of an element. The start time of the element is the
523 * running time of the element when it last went to the PAUSED state. In READY
524 * or after a flushing seek, it is set to 0.
526 * Toplevel elements like #GstPipeline will manage the start_time and
527 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
528 * on such a toplevel element will disable the distribution of the base_time to
529 * the children and can be useful if the application manages the base_time
530 * itself, for example if you want to synchronize capture from multiple
531 * pipelines, and you can also ensure that the pipelines have the same clock.
536 gst_element_set_start_time (GstElement * element, GstClockTime time)
540 g_return_if_fail (GST_IS_ELEMENT (element));
542 GST_OBJECT_LOCK (element);
543 old = GST_ELEMENT_START_TIME (element);
544 GST_ELEMENT_START_TIME (element) = time;
545 GST_OBJECT_UNLOCK (element);
547 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
548 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
549 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
553 * gst_element_get_start_time:
554 * @element: a #GstElement.
556 * Returns the start time of the element. The start time is the
557 * running time of the clock when this element was last put to PAUSED.
559 * Usually the start_time is managed by a toplevel element such as
564 * Returns: the start time of the element.
567 gst_element_get_start_time (GstElement * element)
571 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
573 GST_OBJECT_LOCK (element);
574 result = GST_ELEMENT_START_TIME (element);
575 GST_OBJECT_UNLOCK (element);
582 * gst_element_set_index:
583 * @element: a #GstElement.
584 * @index: (transfer none): a #GstIndex.
586 * Set @index on the element. The refcount of the index
587 * will be increased, any previously set index is unreffed.
592 gst_element_set_index (GstElement * element, GstIndex * index)
594 GstElementClass *oclass;
596 g_return_if_fail (GST_IS_ELEMENT (element));
597 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
599 oclass = GST_ELEMENT_GET_CLASS (element);
601 if (oclass->set_index)
602 oclass->set_index (element, index);
606 * gst_element_get_index:
607 * @element: a #GstElement.
609 * Gets the index from the element.
611 * Returns: (transfer full) (nullable): a #GstIndex or %NULL when no
612 * index was set on the element. unref after usage.
617 gst_element_get_index (GstElement * element)
619 GstElementClass *oclass;
620 GstIndex *result = NULL;
622 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
624 oclass = GST_ELEMENT_GET_CLASS (element);
626 if (oclass->get_index)
627 result = oclass->get_index (element);
634 * gst_element_add_pad:
635 * @element: a #GstElement to add the pad to.
636 * @pad: (transfer full): the #GstPad to add to the element.
638 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
639 * see gst_object_set_parent() for refcounting information.
641 * Pads are not automatically activated so elements should perform the needed
642 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
643 * state. See gst_pad_set_active() for more information about activating pads.
645 * The pad and the element should be unlocked when calling this function.
647 * This function will emit the #GstElement::pad-added signal on the element.
649 * Returns: %TRUE if the pad could be added. This function can fail when
650 * a pad with the same name already existed or the pad already had another
656 gst_element_add_pad (GstElement * element, GstPad * pad)
661 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
662 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
664 /* locking pad to look at the name */
665 GST_OBJECT_LOCK (pad);
666 pad_name = g_strdup (GST_PAD_NAME (pad));
667 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
668 GST_STR_NULL (pad_name));
669 active = GST_PAD_IS_ACTIVE (pad);
670 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
671 GST_OBJECT_UNLOCK (pad);
673 /* then check to see if there's already a pad by that name here */
674 GST_OBJECT_LOCK (element);
675 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
678 /* try to set the pad's parent */
679 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
680 GST_OBJECT_CAST (element))))
683 /* check for active pads */
684 if (!active && (GST_STATE (element) > GST_STATE_READY ||
685 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
686 g_warning ("adding inactive pad '%s' to running element '%s', you need to "
687 "use gst_pad_set_active(pad,TRUE) before adding it.",
688 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
689 gst_pad_set_active (pad, TRUE);
694 /* add it to the list */
695 switch (gst_pad_get_direction (pad)) {
697 element->srcpads = g_list_append (element->srcpads, pad);
698 element->numsrcpads++;
701 element->sinkpads = g_list_append (element->sinkpads, pad);
702 element->numsinkpads++;
707 element->pads = g_list_append (element->pads, pad);
709 element->pads_cookie++;
710 GST_OBJECT_UNLOCK (element);
712 /* emit the PAD_ADDED signal */
713 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
714 GST_TRACER_ELEMENT_ADD_PAD (element, pad);
720 g_critical ("Padname %s is not unique in element %s, not adding",
721 pad_name, GST_ELEMENT_NAME (element));
722 GST_OBJECT_UNLOCK (element);
729 ("Pad %s already has parent when trying to add to element %s",
730 pad_name, GST_ELEMENT_NAME (element));
731 GST_OBJECT_UNLOCK (element);
737 GST_OBJECT_LOCK (pad);
739 ("Trying to add pad %s to element %s, but it has no direction",
740 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
741 GST_OBJECT_UNLOCK (pad);
742 GST_OBJECT_UNLOCK (element);
748 * gst_element_remove_pad:
749 * @element: a #GstElement to remove pad from.
750 * @pad: (transfer full): the #GstPad to remove from the element.
752 * Removes @pad from @element. @pad will be destroyed if it has not been
753 * referenced elsewhere using gst_object_unparent().
755 * This function is used by plugin developers and should not be used
756 * by applications. Pads that were dynamically requested from elements
757 * with gst_element_request_pad() should be released with the
758 * gst_element_release_request_pad() function instead.
760 * Pads are not automatically deactivated so elements should perform the needed
761 * steps to deactivate the pad in case this pad is removed in the PAUSED or
762 * PLAYING state. See gst_pad_set_active() for more information about
765 * The pad and the element should be unlocked when calling this function.
767 * This function will emit the #GstElement::pad-removed signal on the element.
769 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
770 * pad does not belong to the provided element.
775 gst_element_remove_pad (GstElement * element, GstPad * pad)
779 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
780 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
782 /* locking pad to look at the name and parent */
783 GST_OBJECT_LOCK (pad);
784 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
785 GST_STR_NULL (GST_PAD_NAME (pad)));
787 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
789 GST_OBJECT_UNLOCK (pad);
792 if ((peer = gst_pad_get_peer (pad))) {
793 /* window for MT unsafeness, someone else could unlink here
794 * and then we call unlink with wrong pads. The unlink
795 * function would catch this and safely return failed. */
796 if (GST_PAD_IS_SRC (pad))
797 gst_pad_unlink (pad, peer);
799 gst_pad_unlink (peer, pad);
801 gst_object_unref (peer);
804 GST_OBJECT_LOCK (element);
805 /* remove it from the list */
806 switch (gst_pad_get_direction (pad)) {
808 element->srcpads = g_list_remove (element->srcpads, pad);
809 element->numsrcpads--;
812 element->sinkpads = g_list_remove (element->sinkpads, pad);
813 element->numsinkpads--;
816 g_critical ("Removing pad without direction???");
819 element->pads = g_list_remove (element->pads, pad);
821 element->pads_cookie++;
822 GST_OBJECT_UNLOCK (element);
824 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
825 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
826 GST_TRACER_ELEMENT_REMOVE_PAD (element, pad);
827 gst_object_unparent (GST_OBJECT_CAST (pad));
834 /* locking order is element > pad */
835 GST_OBJECT_UNLOCK (pad);
837 GST_OBJECT_LOCK (element);
838 GST_OBJECT_LOCK (pad);
839 g_critical ("Padname %s:%s does not belong to element %s when removing",
840 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
841 GST_OBJECT_UNLOCK (pad);
842 GST_OBJECT_UNLOCK (element);
848 * gst_element_no_more_pads:
849 * @element: a #GstElement
851 * Use this function to signal that the element does not expect any more pads
852 * to show up in the current pipeline. This function should be called whenever
853 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
854 * pad templates use this in combination with autopluggers to figure out that
855 * the element is done initializing its pads.
857 * This function emits the #GstElement::no-more-pads signal.
862 gst_element_no_more_pads (GstElement * element)
864 g_return_if_fail (GST_IS_ELEMENT (element));
866 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
870 pad_compare_name (GstPad * pad1, const gchar * name)
874 GST_OBJECT_LOCK (pad1);
875 result = strcmp (GST_PAD_NAME (pad1), name);
876 GST_OBJECT_UNLOCK (pad1);
882 * gst_element_get_static_pad:
883 * @element: a #GstElement to find a static pad of.
884 * @name: the name of the static #GstPad to retrieve.
886 * Retrieves a pad from @element by name. This version only retrieves
887 * already-existing (i.e. 'static') pads.
889 * Returns: (transfer full) (nullable): the requested #GstPad if
890 * found, otherwise %NULL. unref after usage.
895 gst_element_get_static_pad (GstElement * element, const gchar * name)
898 GstPad *result = NULL;
900 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
901 g_return_val_if_fail (name != NULL, NULL);
903 GST_OBJECT_LOCK (element);
905 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
907 result = GST_PAD_CAST (find->data);
908 gst_object_ref (result);
911 if (result == NULL) {
912 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
913 name, GST_ELEMENT_NAME (element));
915 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
916 GST_ELEMENT_NAME (element), name);
918 GST_OBJECT_UNLOCK (element);
924 gst_element_is_valid_request_template_name (const gchar * templ_name,
928 const gchar *templ_name_ptr, *name_ptr;
929 gboolean next_specifier;
930 guint templ_postfix_len = 0, name_postfix_len = 0;
932 g_return_val_if_fail (templ_name != NULL, FALSE);
933 g_return_val_if_fail (name != NULL, FALSE);
935 /* Is this the template name? */
936 if (strcmp (templ_name, name) == 0)
939 /* otherwise check all the specifiers */
941 /* Because of sanity checks in gst_pad_template_new(), we know that %s
942 * and %d and %u, occurring at the template_name */
943 templ_name_ptr = strchr (templ_name, '%');
945 /* check characters ahead of the specifier */
946 if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
947 || strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
951 /* %s is not allowed for multiple specifiers, just a single specifier can be
952 * accepted in gst_pad_template_new() and can not be mixed with other
953 * specifier '%u' and '%d' */
954 if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
958 name_ptr = name + (templ_name_ptr - templ_name);
960 /* search next specifier, each of specifier should be separated by '_' */
961 templ_name = strchr (templ_name_ptr, '_');
962 name = strchr (name_ptr, '_');
964 /* don't match the number of specifiers */
965 if ((templ_name && !name) || (!templ_name && name))
968 if (templ_name && name)
969 next_specifier = TRUE;
971 next_specifier = FALSE;
973 /* check characters followed by the specifier */
974 if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
975 if (next_specifier) {
976 templ_postfix_len = templ_name - (templ_name_ptr + 2);
977 name_postfix_len = name - name_ptr;
979 templ_postfix_len = strlen (templ_name_ptr + 2);
980 name_postfix_len = strlen (name_ptr);
983 if (strncmp (templ_name_ptr + 2,
984 name_ptr + name_postfix_len - templ_postfix_len,
985 templ_postfix_len) != 0) {
990 /* verify the specifier */
991 if (*(name_ptr) == '%') {
994 len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
996 if (strncmp (name_ptr, templ_name_ptr, len) != 0)
1000 const gchar *specifier;
1001 gchar *target = NULL;
1003 /* extract specifier when it has postfix characters */
1004 if (name_postfix_len > templ_postfix_len) {
1005 target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
1007 specifier = target ? target : name_ptr;
1009 if (*(templ_name_ptr + 1) == 'd') {
1013 tmp = g_ascii_strtoll (specifier, &endptr, 10);
1014 if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
1017 } else if (*(templ_name_ptr + 1) == 'u') {
1021 tmp = g_ascii_strtoull (specifier, &endptr, 10);
1022 if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
1031 } while (next_specifier);
1037 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
1038 const gchar * name, const GstCaps * caps)
1040 GstPad *newpad = NULL;
1041 GstElementClass *oclass;
1043 oclass = GST_ELEMENT_GET_CLASS (element);
1045 #ifndef G_DISABLE_CHECKS
1046 /* Some sanity checking here */
1050 g_return_val_if_fail (gst_element_is_valid_request_template_name
1051 (templ->name_template, name), NULL);
1053 pad = gst_element_get_static_pad (element, name);
1055 gst_object_unref (pad);
1056 /* FIXME 2.0: Change this to g_return_val_if_fail() */
1057 g_critical ("Element %s already has a pad named %s, the behaviour of "
1058 " gst_element_get_request_pad() for existing pads is undefined!",
1059 GST_ELEMENT_NAME (element), name);
1064 if (oclass->request_new_pad)
1065 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1068 gst_object_ref (newpad);
1074 * gst_element_get_request_pad:
1075 * @element: a #GstElement to find a request pad of.
1076 * @name: the name of the request #GstPad to retrieve.
1078 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1079 * retrieves request pads. The pad should be released with
1080 * gst_element_release_request_pad().
1082 * This method is slower than manually getting the pad template and calling
1083 * gst_element_request_pad() if the pads should have a specific name (e.g.
1084 * @name is "src_1" instead of "src_\%u").
1086 * Returns: (transfer full) (nullable): requested #GstPad if found,
1087 * otherwise %NULL. Release after usage.
1090 gst_element_get_request_pad (GstElement * element, const gchar * name)
1092 GstPadTemplate *templ = NULL;
1094 const gchar *req_name = NULL;
1095 gboolean templ_found = FALSE;
1097 GstElementClass *class;
1099 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1100 g_return_val_if_fail (name != NULL, NULL);
1102 class = GST_ELEMENT_GET_CLASS (element);
1104 templ = gst_element_class_get_request_pad_template (class, name);
1106 req_name = strstr (name, "%") ? NULL : name;
1109 /* there is no % in the name, try to find a matching template */
1110 list = class->padtemplates;
1111 while (!templ_found && list) {
1112 templ = (GstPadTemplate *) list->data;
1113 if (templ->presence == GST_PAD_REQUEST) {
1114 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1115 templ->name_template);
1116 if (gst_element_is_valid_request_template_name (templ->name_template,
1130 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1136 * gst_element_request_pad: (virtual request_new_pad)
1137 * @element: a #GstElement to find a request pad of.
1138 * @templ: a #GstPadTemplate of which we want a pad of.
1139 * @name: (transfer none) (allow-none): the name of the request #GstPad
1140 * to retrieve. Can be %NULL.
1141 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1142 * request. Can be %NULL.
1144 * Retrieves a request pad from the element according to the provided template.
1145 * Pad templates can be looked up using
1146 * gst_element_factory_get_static_pad_templates().
1148 * The pad should be released with gst_element_release_request_pad().
1150 * Returns: (transfer full) (nullable): requested #GstPad if found,
1151 * otherwise %NULL. Release after usage.
1154 gst_element_request_pad (GstElement * element,
1155 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1157 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1158 g_return_val_if_fail (templ != NULL, NULL);
1159 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1161 return _gst_element_request_pad (element, templ, name, caps);
1164 static GstIterator *
1165 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1167 GstIterator *result;
1169 GST_OBJECT_LOCK (element);
1170 result = gst_iterator_new_list (GST_TYPE_PAD,
1171 GST_OBJECT_GET_LOCK (element),
1172 &element->pads_cookie, padlist, (GObject *) element, NULL);
1173 GST_OBJECT_UNLOCK (element);
1179 * gst_element_iterate_pads:
1180 * @element: a #GstElement to iterate pads of.
1182 * Retrieves an iterator of @element's pads. The iterator should
1183 * be freed after usage. Also more specialized iterators exists such as
1184 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1186 * The order of pads returned by the iterator will be the order in which
1187 * the pads were added to the element.
1189 * Returns: (transfer full): the #GstIterator of #GstPad.
1194 gst_element_iterate_pads (GstElement * element)
1196 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1198 return gst_element_iterate_pad_list (element, &element->pads);
1202 * gst_element_iterate_src_pads:
1203 * @element: a #GstElement.
1205 * Retrieves an iterator of @element's source pads.
1207 * The order of pads returned by the iterator will be the order in which
1208 * the pads were added to the element.
1210 * Returns: (transfer full): the #GstIterator of #GstPad.
1215 gst_element_iterate_src_pads (GstElement * element)
1217 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1219 return gst_element_iterate_pad_list (element, &element->srcpads);
1223 * gst_element_iterate_sink_pads:
1224 * @element: a #GstElement.
1226 * Retrieves an iterator of @element's sink pads.
1228 * The order of pads returned by the iterator will be the order in which
1229 * the pads were added to the element.
1231 * Returns: (transfer full): the #GstIterator of #GstPad.
1236 gst_element_iterate_sink_pads (GstElement * element)
1238 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1240 return gst_element_iterate_pad_list (element, &element->sinkpads);
1244 * gst_element_class_add_pad_template:
1245 * @klass: the #GstElementClass to add the pad template to.
1246 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1248 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1249 * functions of classes. If a pad template with the same name as an already
1250 * existing one is added the old one is replaced by the new one.
1254 gst_element_class_add_pad_template (GstElementClass * klass,
1255 GstPadTemplate * templ)
1257 GList *template_list = klass->padtemplates;
1259 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1260 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1262 /* If we already have a pad template with the same name replace the
1264 while (template_list) {
1265 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1267 /* Found pad with the same name, replace and return */
1268 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1269 gst_object_unref (padtempl);
1270 template_list->data = templ;
1273 template_list = g_list_next (template_list);
1276 /* Take ownership of the floating ref */
1277 gst_object_ref_sink (templ);
1279 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1280 klass->numpadtemplates++;
1284 * gst_element_class_add_static_pad_template:
1285 * @klass: the #GstElementClass to add the pad template to.
1286 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1288 * Adds a pad template to an element class based on the static pad template
1289 * @templ. This is mainly used in the _class_init functions of element
1290 * implementations. If a pad template with the same name already exists,
1291 * the old one is replaced by the new one.
1296 gst_element_class_add_static_pad_template (GstElementClass * klass,
1297 GstStaticPadTemplate * static_templ)
1299 gst_element_class_add_pad_template (klass,
1300 gst_static_pad_template_get (static_templ));
1304 * gst_element_class_add_metadata:
1305 * @klass: class to set metadata for
1306 * @key: the key to set
1307 * @value: the value to set
1309 * Set @key with @value as metadata in @klass.
1312 gst_element_class_add_metadata (GstElementClass * klass,
1313 const gchar * key, const gchar * value)
1315 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1316 g_return_if_fail (key != NULL);
1317 g_return_if_fail (value != NULL);
1319 gst_structure_set ((GstStructure *) klass->metadata,
1320 key, G_TYPE_STRING, value, NULL);
1324 * gst_element_class_add_static_metadata:
1325 * @klass: class to set metadata for
1326 * @key: the key to set
1327 * @value: the value to set
1329 * Set @key with @value as metadata in @klass.
1331 * Same as gst_element_class_add_metadata(), but @value must be a static string
1332 * or an inlined string, as it will not be copied. (GStreamer plugins will
1333 * be made resident once loaded, so this function can be used even from
1334 * dynamically loaded plugins.)
1337 gst_element_class_add_static_metadata (GstElementClass * klass,
1338 const gchar * key, const gchar * value)
1340 GValue val = G_VALUE_INIT;
1342 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1343 g_return_if_fail (key != NULL);
1344 g_return_if_fail (value != NULL);
1346 g_value_init (&val, G_TYPE_STRING);
1347 g_value_set_static_string (&val, value);
1348 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1352 * gst_element_class_set_metadata:
1353 * @klass: class to set metadata for
1354 * @longname: The long English name of the element. E.g. "File Sink"
1355 * @classification: String describing the type of element, as an unordered list
1356 * separated with slashes ('/'). See draft-klass.txt of the design docs
1357 * for more details and common types. E.g: "Sink/File"
1358 * @description: Sentence describing the purpose of the element.
1359 * E.g: "Write stream to a file"
1360 * @author: Name and contact details of the author(s). Use \n to separate
1361 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1363 * Sets the detailed information for a #GstElementClass.
1364 * <note>This function is for use in _class_init functions only.</note>
1367 gst_element_class_set_metadata (GstElementClass * klass,
1368 const gchar * longname, const gchar * classification,
1369 const gchar * description, const gchar * author)
1371 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1372 g_return_if_fail (longname != NULL && *longname != '\0');
1373 g_return_if_fail (classification != NULL && *classification != '\0');
1374 g_return_if_fail (description != NULL && *description != '\0');
1375 g_return_if_fail (author != NULL && *author != '\0');
1377 gst_structure_id_set ((GstStructure *) klass->metadata,
1378 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1379 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1380 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1381 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1385 * gst_element_class_set_static_metadata:
1386 * @klass: class to set metadata for
1387 * @longname: The long English name of the element. E.g. "File Sink"
1388 * @classification: String describing the type of element, as an unordered list
1389 * separated with slashes ('/'). See draft-klass.txt of the design docs
1390 * for more details and common types. E.g: "Sink/File"
1391 * @description: Sentence describing the purpose of the element.
1392 * E.g: "Write stream to a file"
1393 * @author: Name and contact details of the author(s). Use \n to separate
1394 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1396 * Sets the detailed information for a #GstElementClass.
1397 * <note>This function is for use in _class_init functions only.</note>
1399 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1400 * @description, and @author must be static strings or inlined strings, as
1401 * they will not be copied. (GStreamer plugins will be made resident once
1402 * loaded, so this function can be used even from dynamically loaded plugins.)
1405 gst_element_class_set_static_metadata (GstElementClass * klass,
1406 const gchar * longname, const gchar * classification,
1407 const gchar * description, const gchar * author)
1409 GstStructure *s = (GstStructure *) klass->metadata;
1410 GValue val = G_VALUE_INIT;
1412 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1413 g_return_if_fail (longname != NULL && *longname != '\0');
1414 g_return_if_fail (classification != NULL && *classification != '\0');
1415 g_return_if_fail (description != NULL && *description != '\0');
1416 g_return_if_fail (author != NULL && *author != '\0');
1418 g_value_init (&val, G_TYPE_STRING);
1420 g_value_set_static_string (&val, longname);
1421 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1423 g_value_set_static_string (&val, classification);
1424 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1426 g_value_set_static_string (&val, description);
1427 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1430 g_value_set_static_string (&val, author);
1431 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1435 * gst_element_class_get_metadata:
1436 * @klass: class to get metadata for
1437 * @key: the key to get
1439 * Get metadata with @key in @klass.
1441 * Returns: the metadata for @key.
1444 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1446 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1447 g_return_val_if_fail (key != NULL, NULL);
1449 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1453 * gst_element_class_get_pad_template_list:
1454 * @element_class: a #GstElementClass to get pad templates of.
1456 * Retrieves a list of the pad templates associated with @element_class. The
1457 * list must not be modified by the calling code.
1458 * <note>If you use this function in the #GInstanceInitFunc of an object class
1459 * that has subclasses, make sure to pass the g_class parameter of the
1460 * #GInstanceInitFunc here.</note>
1462 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1466 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1468 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1470 return element_class->padtemplates;
1474 * gst_element_class_get_pad_template:
1475 * @element_class: a #GstElementClass to get the pad template of.
1476 * @name: the name of the #GstPadTemplate to get.
1478 * Retrieves a padtemplate from @element_class with the given name.
1479 * <note>If you use this function in the #GInstanceInitFunc of an object class
1480 * that has subclasses, make sure to pass the g_class parameter of the
1481 * #GInstanceInitFunc here.</note>
1483 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1484 * given name, or %NULL if none was found. No unreferencing is
1488 gst_element_class_get_pad_template (GstElementClass *
1489 element_class, const gchar * name)
1493 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1494 g_return_val_if_fail (name != NULL, NULL);
1496 padlist = element_class->padtemplates;
1499 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1501 if (strcmp (padtempl->name_template, name) == 0)
1504 padlist = g_list_next (padlist);
1510 static GstPadTemplate *
1511 gst_element_class_get_request_pad_template (GstElementClass *
1512 element_class, const gchar * name)
1514 GstPadTemplate *tmpl;
1516 tmpl = gst_element_class_get_pad_template (element_class, name);
1517 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1523 /* get a random pad on element of the given direction.
1524 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1527 gst_element_get_random_pad (GstElement * element,
1528 gboolean need_linked, GstPadDirection dir)
1530 GstPad *result = NULL;
1533 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1537 GST_OBJECT_LOCK (element);
1538 pads = element->srcpads;
1541 GST_OBJECT_LOCK (element);
1542 pads = element->sinkpads;
1545 goto wrong_direction;
1547 for (; pads; pads = g_list_next (pads)) {
1548 GstPad *pad = GST_PAD_CAST (pads->data);
1550 GST_OBJECT_LOCK (pad);
1551 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1552 GST_DEBUG_PAD_NAME (pad));
1554 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1555 /* if we require a linked pad, and it is not linked, continue the
1557 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1558 GST_DEBUG_PAD_NAME (pad));
1559 GST_OBJECT_UNLOCK (pad);
1562 /* found a pad, stop search */
1563 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1564 GST_DEBUG_PAD_NAME (pad));
1565 GST_OBJECT_UNLOCK (pad);
1571 gst_object_ref (result);
1573 GST_OBJECT_UNLOCK (element);
1577 /* ERROR handling */
1580 g_warning ("unknown pad direction %d", dir);
1586 gst_element_default_send_event (GstElement * element, GstEvent * event)
1588 gboolean result = FALSE;
1591 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1592 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1593 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1596 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1597 "pushing %s event to random %s pad %s:%s",
1598 GST_EVENT_TYPE_NAME (event),
1599 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1600 GST_DEBUG_PAD_NAME (pad));
1602 result = gst_pad_send_event (pad, event);
1603 gst_object_unref (pad);
1605 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1606 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1607 gst_event_unref (event);
1613 * gst_element_send_event:
1614 * @element: a #GstElement to send the event to.
1615 * @event: (transfer full): the #GstEvent to send to the element.
1617 * Sends an event to an element. If the element doesn't implement an
1618 * event handler, the event will be pushed on a random linked sink pad for
1619 * downstream events or a random linked source pad for upstream events.
1621 * This function takes ownership of the provided event so you should
1622 * gst_event_ref() it if you want to reuse the event after this call.
1626 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1627 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1630 gst_element_send_event (GstElement * element, GstEvent * event)
1632 GstElementClass *oclass;
1633 gboolean result = FALSE;
1635 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1636 g_return_val_if_fail (event != NULL, FALSE);
1638 oclass = GST_ELEMENT_GET_CLASS (element);
1640 GST_STATE_LOCK (element);
1641 if (oclass->send_event) {
1642 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1643 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1644 result = oclass->send_event (element, event);
1646 gst_event_unref (event);
1648 GST_STATE_UNLOCK (element);
1655 * @element: a #GstElement to send the event to.
1656 * @rate: The new playback rate
1657 * @format: The format of the seek values
1658 * @flags: The optional seek flags.
1659 * @start_type: The type and flags for the new start position
1660 * @start: The value of the new start position
1661 * @stop_type: The type and flags for the new stop position
1662 * @stop: The value of the new stop position
1664 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1665 * the parameters. The seek event is sent to the element using
1666 * gst_element_send_event().
1670 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1671 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1674 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1675 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1676 GstSeekType stop_type, gint64 stop)
1681 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1684 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1686 result = gst_element_send_event (element, event);
1692 gst_element_default_query (GstElement * element, GstQuery * query)
1694 gboolean result = FALSE;
1697 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1699 result = gst_pad_query (pad, query);
1701 gst_object_unref (pad);
1703 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1705 GstPad *peer = gst_pad_get_peer (pad);
1708 result = gst_pad_query (peer, query);
1710 gst_object_unref (peer);
1712 gst_object_unref (pad);
1719 * gst_element_query:
1720 * @element: a #GstElement to perform the query on.
1721 * @query: (transfer none): the #GstQuery.
1723 * Performs a query on the given element.
1725 * For elements that don't implement a query handler, this function
1726 * forwards the query to a random srcpad or to the peer of a
1727 * random linked sinkpad of this element.
1729 * Please note that some queries might need a running pipeline to work.
1731 * Returns: %TRUE if the query could be performed.
1736 gst_element_query (GstElement * element, GstQuery * query)
1738 GstElementClass *klass;
1739 gboolean res = FALSE;
1741 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1742 g_return_val_if_fail (query != NULL, FALSE);
1744 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1746 klass = GST_ELEMENT_GET_CLASS (element);
1748 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1749 GST_ELEMENT_NAME (element));
1750 res = klass->query (element, query);
1753 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1758 gst_element_post_message_default (GstElement * element, GstMessage * message)
1761 gboolean result = FALSE;
1763 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1764 g_return_val_if_fail (message != NULL, FALSE);
1766 GST_OBJECT_LOCK (element);
1769 if (G_UNLIKELY (bus == NULL))
1772 gst_object_ref (bus);
1773 GST_OBJECT_UNLOCK (element);
1775 /* we release the element lock when posting the message so that any
1776 * (synchronous) message handlers can operate on the element */
1777 result = gst_bus_post (bus, message);
1778 gst_object_unref (bus);
1785 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1786 "not posting message %p: no bus", message);
1787 GST_OBJECT_UNLOCK (element);
1788 gst_message_unref (message);
1794 * gst_element_post_message:
1795 * @element: a #GstElement posting the message
1796 * @message: (transfer full): a #GstMessage to post
1798 * Post a message on the element's #GstBus. This function takes ownership of the
1799 * message; if you want to access the message after this call, you should add an
1800 * additional reference before calling.
1802 * Returns: %TRUE if the message was successfully posted. The function returns
1803 * %FALSE if the element did not have a bus.
1808 gst_element_post_message (GstElement * element, GstMessage * message)
1810 GstElementClass *klass;
1811 gboolean res = FALSE;
1813 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1814 g_return_val_if_fail (message != NULL, FALSE);
1816 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1818 klass = GST_ELEMENT_GET_CLASS (element);
1819 if (klass->post_message)
1820 res = klass->post_message (element, message);
1822 gst_message_unref (message);
1824 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1829 * _gst_element_error_printf:
1830 * @format: (allow-none): the printf-like format to use, or %NULL
1832 * This function is only used internally by the gst_element_error() macro.
1834 * Returns: (transfer full) (nullable): a newly allocated string, or
1835 * %NULL if the format was %NULL or ""
1840 _gst_element_error_printf (const gchar * format, ...)
1851 va_start (args, format);
1853 len = __gst_vasprintf (&buffer, format, args);
1864 * gst_element_message_full_with_details:
1865 * @element: a #GstElement to send message from
1866 * @type: the #GstMessageType
1867 * @domain: the GStreamer GError domain this message belongs to
1868 * @code: the GError code belonging to the domain
1869 * @text: (allow-none) (transfer full): an allocated text string to be used
1870 * as a replacement for the default message connected to code,
1872 * @debug: (allow-none) (transfer full): an allocated debug message to be
1873 * used as a replacement for the default debugging information,
1875 * @file: the source code file where the error was generated
1876 * @function: the source code function where the error was generated
1877 * @line: the source code line where the error was generated
1878 * @structure:(transfer full): optional details structure
1880 * Post an error, warning or info message on the bus from inside an element.
1882 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1883 * #GST_MESSAGE_INFO.
1887 void gst_element_message_full_with_details
1888 (GstElement * element, GstMessageType type,
1889 GQuark domain, gint code, gchar * text,
1890 gchar * debug, const gchar * file, const gchar * function, gint line,
1891 GstStructure * structure)
1893 GError *gerror = NULL;
1897 gboolean has_debug = TRUE;
1898 GstMessage *message = NULL;
1901 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1902 g_return_if_fail (GST_IS_ELEMENT (element));
1903 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1904 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1906 /* check if we send the given text or the default error text */
1907 if ((text == NULL) || (text[0] == 0)) {
1908 /* text could have come from g_strdup_printf (""); */
1910 sent_text = gst_error_get_message (domain, code);
1914 /* construct a sent_debug with extra information from source */
1915 if ((debug == NULL) || (debug[0] == 0)) {
1916 /* debug could have come from g_strdup_printf (""); */
1920 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1922 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1923 file, line, function, name, debug);
1925 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1926 file, line, function, name);
1930 /* create gerror and post message */
1931 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1933 gerror = g_error_new_literal (domain, code, sent_text);
1936 case GST_MESSAGE_ERROR:
1938 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1939 sent_debug, structure);
1941 case GST_MESSAGE_WARNING:
1943 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1944 gerror, sent_debug, structure);
1946 case GST_MESSAGE_INFO:
1948 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1949 sent_debug, structure);
1952 g_assert_not_reached ();
1956 gst_element_post_message (element, message);
1958 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1959 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1962 g_error_free (gerror);
1963 g_free (sent_debug);
1968 * gst_element_message_full:
1969 * @element: a #GstElement to send message from
1970 * @type: the #GstMessageType
1971 * @domain: the GStreamer GError domain this message belongs to
1972 * @code: the GError code belonging to the domain
1973 * @text: (allow-none) (transfer full): an allocated text string to be used
1974 * as a replacement for the default message connected to code,
1976 * @debug: (allow-none) (transfer full): an allocated debug message to be
1977 * used as a replacement for the default debugging information,
1979 * @file: the source code file where the error was generated
1980 * @function: the source code function where the error was generated
1981 * @line: the source code line where the error was generated
1983 * Post an error, warning or info message on the bus from inside an element.
1985 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1986 * #GST_MESSAGE_INFO.
1990 void gst_element_message_full
1991 (GstElement * element, GstMessageType type,
1992 GQuark domain, gint code, gchar * text,
1993 gchar * debug, const gchar * file, const gchar * function, gint line)
1995 gst_element_message_full_with_details (element, type, domain, code, text,
1996 debug, file, function, line, NULL);
2000 * gst_element_is_locked_state:
2001 * @element: a #GstElement.
2003 * Checks if the state of an element is locked.
2004 * If the state of an element is locked, state changes of the parent don't
2005 * affect the element.
2006 * This way you can leave currently unused elements inside bins. Just lock their
2007 * state before changing the state from #GST_STATE_NULL.
2011 * Returns: %TRUE, if the element's state is locked.
2014 gst_element_is_locked_state (GstElement * element)
2018 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2020 GST_OBJECT_LOCK (element);
2021 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2022 GST_OBJECT_UNLOCK (element);
2028 * gst_element_set_locked_state:
2029 * @element: a #GstElement
2030 * @locked_state: %TRUE to lock the element's state
2032 * Locks the state of an element, so state changes of the parent don't affect
2033 * this element anymore.
2037 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2038 * or the elements state-locking needed no change.
2041 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2045 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2047 GST_OBJECT_LOCK (element);
2048 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2050 if (G_UNLIKELY (old == locked_state))
2054 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2055 GST_ELEMENT_NAME (element));
2056 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2058 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2059 GST_ELEMENT_NAME (element));
2060 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2062 GST_OBJECT_UNLOCK (element);
2068 GST_CAT_DEBUG (GST_CAT_STATES,
2069 "elements %s was already in locked state %d",
2070 GST_ELEMENT_NAME (element), old);
2071 GST_OBJECT_UNLOCK (element);
2078 * gst_element_sync_state_with_parent:
2079 * @element: a #GstElement.
2081 * Tries to change the state of the element to the same as its parent.
2082 * If this function returns %FALSE, the state of element is undefined.
2084 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2089 gst_element_sync_state_with_parent (GstElement * element)
2093 GstStateChangeReturn ret;
2095 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2097 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2098 GstState parent_current, parent_pending;
2100 GST_OBJECT_LOCK (parent);
2101 parent_current = GST_STATE (parent);
2102 parent_pending = GST_STATE_PENDING (parent);
2103 GST_OBJECT_UNLOCK (parent);
2105 /* set to pending if there is one, else we set it to the current state of
2107 if (parent_pending != GST_STATE_VOID_PENDING)
2108 target = parent_pending;
2110 target = parent_current;
2112 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2113 "syncing state (%s) to parent %s %s (%s, %s)",
2114 gst_element_state_get_name (GST_STATE (element)),
2115 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2116 gst_element_state_get_name (parent_current),
2117 gst_element_state_get_name (parent_pending));
2119 ret = gst_element_set_state (element, target);
2120 if (ret == GST_STATE_CHANGE_FAILURE)
2123 gst_object_unref (parent);
2127 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2134 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2135 "syncing state failed (%s)",
2136 gst_element_state_change_return_get_name (ret));
2137 gst_object_unref (parent);
2143 static GstStateChangeReturn
2144 gst_element_get_state_func (GstElement * element,
2145 GstState * state, GstState * pending, GstClockTime timeout)
2147 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2148 GstState old_pending;
2150 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2151 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2153 GST_OBJECT_LOCK (element);
2154 ret = GST_STATE_RETURN (element);
2155 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2156 gst_element_state_change_return_get_name (ret));
2158 /* we got an error, report immediately */
2159 if (ret == GST_STATE_CHANGE_FAILURE)
2162 /* we got no_preroll, report immediately */
2163 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2166 /* no need to wait async if we are not async */
2167 if (ret != GST_STATE_CHANGE_ASYNC)
2170 old_pending = GST_STATE_PENDING (element);
2171 if (old_pending != GST_STATE_VOID_PENDING) {
2175 /* get cookie to detect state changes during waiting */
2176 cookie = element->state_cookie;
2178 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2179 "waiting for element to commit state");
2181 /* we have a pending state change, wait for it to complete */
2182 if (timeout != GST_CLOCK_TIME_NONE) {
2184 /* make timeout absolute */
2185 end_time = g_get_monotonic_time () + (timeout / 1000);
2186 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2188 GST_STATE_WAIT (element);
2193 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2194 /* timeout triggered */
2195 ret = GST_STATE_CHANGE_ASYNC;
2197 if (cookie != element->state_cookie)
2200 /* could be success or failure */
2201 if (old_pending == GST_STATE (element)) {
2202 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2203 ret = GST_STATE_CHANGE_SUCCESS;
2205 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2206 ret = GST_STATE_CHANGE_FAILURE;
2209 /* if nothing is pending anymore we can return SUCCESS */
2210 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2211 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2212 ret = GST_STATE_CHANGE_SUCCESS;
2218 *state = GST_STATE (element);
2220 *pending = GST_STATE_PENDING (element);
2222 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2223 "state current: %s, pending: %s, result: %s",
2224 gst_element_state_get_name (GST_STATE (element)),
2225 gst_element_state_get_name (GST_STATE_PENDING (element)),
2226 gst_element_state_change_return_get_name (ret));
2227 GST_OBJECT_UNLOCK (element);
2234 *state = GST_STATE_VOID_PENDING;
2236 *pending = GST_STATE_VOID_PENDING;
2238 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2240 GST_OBJECT_UNLOCK (element);
2242 return GST_STATE_CHANGE_FAILURE;
2247 * gst_element_get_state:
2248 * @element: a #GstElement to get the state of.
2249 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2251 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2252 * state. Can be %NULL.
2253 * @timeout: a #GstClockTime to specify the timeout for an async
2254 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2256 * Gets the state of the element.
2258 * For elements that performed an ASYNC state change, as reported by
2259 * gst_element_set_state(), this function will block up to the
2260 * specified timeout value for the state change to complete.
2261 * If the element completes the state change or goes into
2262 * an error, this function returns immediately with a return value of
2263 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2265 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2266 * returns the current and pending state immediately.
2268 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2269 * successfully changed its state but is not able to provide data yet.
2270 * This mostly happens for live sources that only produce data in
2271 * %GST_STATE_PLAYING. While the state change return is equivalent to
2272 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2273 * some sink elements might not be able to complete their state change because
2274 * an element is not producing data to complete the preroll. When setting the
2275 * element to playing, the preroll will complete and playback will start.
2277 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2278 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2279 * element is still performing a state change or
2280 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2284 GstStateChangeReturn
2285 gst_element_get_state (GstElement * element,
2286 GstState * state, GstState * pending, GstClockTime timeout)
2288 GstElementClass *oclass;
2289 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2291 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2293 oclass = GST_ELEMENT_GET_CLASS (element);
2295 if (oclass->get_state)
2296 result = (oclass->get_state) (element, state, pending, timeout);
2302 * gst_element_abort_state:
2303 * @element: a #GstElement to abort the state of.
2305 * Abort the state change of the element. This function is used
2306 * by elements that do asynchronous state changes and find out
2307 * something is wrong.
2309 * This function should be called with the STATE_LOCK held.
2314 gst_element_abort_state (GstElement * element)
2318 #ifndef GST_DISABLE_GST_DEBUG
2322 g_return_if_fail (GST_IS_ELEMENT (element));
2324 GST_OBJECT_LOCK (element);
2325 pending = GST_STATE_PENDING (element);
2327 if (pending == GST_STATE_VOID_PENDING ||
2328 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2329 goto nothing_aborted;
2331 #ifndef GST_DISABLE_GST_DEBUG
2332 old_state = GST_STATE (element);
2334 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2335 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2336 gst_element_state_get_name (pending));
2340 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2342 GST_STATE_BROADCAST (element);
2343 GST_OBJECT_UNLOCK (element);
2349 GST_OBJECT_UNLOCK (element);
2354 /* Not static because GstBin has manual state handling too */
2356 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2357 GstState newstate, GstState pending)
2359 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2360 GstMessage *message;
2362 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2363 "notifying about state-changed %s to %s (%s pending)",
2364 gst_element_state_get_name (oldstate),
2365 gst_element_state_get_name (newstate),
2366 gst_element_state_get_name (pending));
2368 if (klass->state_changed)
2369 klass->state_changed (element, oldstate, newstate, pending);
2371 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2372 oldstate, newstate, pending);
2373 gst_element_post_message (element, message);
2377 * gst_element_continue_state:
2378 * @element: a #GstElement to continue the state change of.
2379 * @ret: The previous state return value
2381 * Commit the state change of the element and proceed to the next
2382 * pending state if any. This function is used
2383 * by elements that do asynchronous state changes.
2384 * The core will normally call this method automatically when an
2385 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2387 * If after calling this method the element still has not reached
2388 * the pending state, the next state change is performed.
2390 * This method is used internally and should normally not be called by plugins
2393 * Returns: The result of the commit state change.
2397 GstStateChangeReturn
2398 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2400 GstStateChangeReturn old_ret;
2401 GstState old_state, old_next;
2402 GstState current, next, pending;
2403 GstStateChange transition;
2405 GST_OBJECT_LOCK (element);
2406 old_ret = GST_STATE_RETURN (element);
2407 GST_STATE_RETURN (element) = ret;
2408 pending = GST_STATE_PENDING (element);
2410 /* check if there is something to commit */
2411 if (pending == GST_STATE_VOID_PENDING)
2412 goto nothing_pending;
2414 old_state = GST_STATE (element);
2415 /* this is the state we should go to next */
2416 old_next = GST_STATE_NEXT (element);
2417 /* update current state */
2418 current = GST_STATE (element) = old_next;
2420 /* see if we reached the final state */
2421 if (pending == current)
2424 next = GST_STATE_GET_NEXT (current, pending);
2425 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2427 GST_STATE_NEXT (element) = next;
2429 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2430 GST_OBJECT_UNLOCK (element);
2432 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2433 "committing state from %s to %s, pending %s, next %s",
2434 gst_element_state_get_name (old_state),
2435 gst_element_state_get_name (old_next),
2436 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2438 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2440 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2441 "continue state change %s to %s, final %s",
2442 gst_element_state_get_name (current),
2443 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2445 ret = gst_element_change_state (element, transition);
2451 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2452 GST_OBJECT_UNLOCK (element);
2457 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2458 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2460 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2461 "completed state change to %s", gst_element_state_get_name (pending));
2462 GST_OBJECT_UNLOCK (element);
2464 /* don't post silly messages with the same state. This can happen
2465 * when an element state is changed to what it already was. For bins
2466 * this can be the result of a lost state, which we check with the
2467 * previous return value.
2468 * We do signal the cond though as a _get_state() might be blocking
2470 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2471 _priv_gst_element_state_changed (element, old_state, old_next,
2472 GST_STATE_VOID_PENDING);
2474 GST_STATE_BROADCAST (element);
2481 * gst_element_lost_state:
2482 * @element: a #GstElement the state is lost of
2484 * Brings the element to the lost state. The current state of the
2485 * element is copied to the pending state so that any call to
2486 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2488 * An ASYNC_START message is posted. If the element was PLAYING, it will
2489 * go to PAUSED. The element will be restored to its PLAYING state by
2490 * the parent pipeline when it prerolls again.
2492 * This is mostly used for elements that lost their preroll buffer
2493 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2494 * they will go to their pending state again when a new preroll buffer is
2495 * queued. This function can only be called when the element is currently
2496 * not in error or an async state change.
2498 * This function is used internally and should normally not be called from
2499 * plugins or applications.
2502 gst_element_lost_state (GstElement * element)
2504 GstState old_state, new_state;
2505 GstMessage *message;
2507 g_return_if_fail (GST_IS_ELEMENT (element));
2509 GST_OBJECT_LOCK (element);
2510 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2513 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2514 goto only_async_start;
2516 old_state = GST_STATE (element);
2518 /* when we were PLAYING, the new state is PAUSED. We will also not
2519 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2520 * when we preroll. */
2521 if (old_state > GST_STATE_PAUSED)
2522 new_state = GST_STATE_PAUSED;
2524 new_state = old_state;
2526 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2527 "lost state of %s to %s", gst_element_state_get_name (old_state),
2528 gst_element_state_get_name (new_state));
2530 GST_STATE (element) = new_state;
2531 GST_STATE_NEXT (element) = new_state;
2532 GST_STATE_PENDING (element) = new_state;
2533 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2534 GST_OBJECT_UNLOCK (element);
2536 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2538 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2539 gst_element_post_message (element, message);
2545 GST_OBJECT_UNLOCK (element);
2550 GST_OBJECT_UNLOCK (element);
2552 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2553 gst_element_post_message (element, message);
2559 * gst_element_set_state:
2560 * @element: a #GstElement to change state of.
2561 * @state: the element's new #GstState.
2563 * Sets the state of the element. This function will try to set the
2564 * requested state by going through all the intermediary states and calling
2565 * the class's state change function for each.
2567 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2568 * element will perform the remainder of the state change asynchronously in
2570 * An application can use gst_element_get_state() to wait for the completion
2571 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2572 * %GST_MESSAGE_STATE_CHANGED on the bus.
2574 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2575 * #GST_STATE_CHANGE_ASYNC.
2577 * Returns: Result of the state change using #GstStateChangeReturn.
2581 GstStateChangeReturn
2582 gst_element_set_state (GstElement * element, GstState state)
2584 GstElementClass *oclass;
2585 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2587 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2589 oclass = GST_ELEMENT_GET_CLASS (element);
2591 if (oclass->set_state)
2592 result = (oclass->set_state) (element, state);
2598 * default set state function, calculates the next state based
2599 * on current state and calls the change_state function
2601 static GstStateChangeReturn
2602 gst_element_set_state_func (GstElement * element, GstState state)
2604 GstState current, next, old_pending;
2605 GstStateChangeReturn ret;
2606 GstStateChange transition;
2607 GstStateChangeReturn old_ret;
2609 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2611 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2612 gst_element_state_get_name (state));
2614 /* state lock is taken to protect the set_state() and get_state()
2615 * procedures, it does not lock any variables. */
2616 GST_STATE_LOCK (element);
2618 /* now calculate how to get to the new state */
2619 GST_OBJECT_LOCK (element);
2620 old_ret = GST_STATE_RETURN (element);
2621 /* previous state change returned an error, remove all pending
2622 * and next states */
2623 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2624 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2625 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2626 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2629 current = GST_STATE (element);
2630 next = GST_STATE_NEXT (element);
2631 old_pending = GST_STATE_PENDING (element);
2633 /* this is the (new) state we should go to. TARGET is the last state we set on
2635 if (state != GST_STATE_TARGET (element)) {
2636 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2637 "setting target state to %s", gst_element_state_get_name (state));
2638 GST_STATE_TARGET (element) = state;
2639 /* increment state cookie so that we can track each state change. We only do
2640 * this if this is actually a new state change. */
2641 element->state_cookie++;
2643 GST_STATE_PENDING (element) = state;
2645 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2646 "current %s, old_pending %s, next %s, old return %s",
2647 gst_element_state_get_name (current),
2648 gst_element_state_get_name (old_pending),
2649 gst_element_state_get_name (next),
2650 gst_element_state_change_return_get_name (old_ret));
2652 /* if the element was busy doing a state change, we just update the
2653 * target state, it'll get to it async then. */
2654 if (old_pending != GST_STATE_VOID_PENDING) {
2655 /* upwards state change will happen ASYNC */
2656 if (old_pending <= state)
2658 /* element is going to this state already */
2659 else if (next == state)
2661 /* element was performing an ASYNC upward state change and
2662 * we request to go downward again. Start from the next pending
2664 else if (next > state
2665 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2669 next = GST_STATE_GET_NEXT (current, state);
2670 /* now we store the next state */
2671 GST_STATE_NEXT (element) = next;
2672 /* mark busy, we need to check that there is actually a state change
2673 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2674 * the default element change_state function has no way to know what the
2675 * old value was... could consider this a FIXME...*/
2676 if (current != next)
2677 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2679 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2681 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2682 "%s: setting state from %s to %s",
2683 (next != state ? "intermediate" : "final"),
2684 gst_element_state_get_name (current), gst_element_state_get_name (next));
2686 /* now signal any waiters, they will error since the cookie was incremented */
2687 GST_STATE_BROADCAST (element);
2689 GST_OBJECT_UNLOCK (element);
2691 ret = gst_element_change_state (element, transition);
2693 GST_STATE_UNLOCK (element);
2695 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2696 gst_element_state_change_return_get_name (ret));
2702 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2703 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2704 "element was busy with async state change");
2705 GST_OBJECT_UNLOCK (element);
2707 GST_STATE_UNLOCK (element);
2709 return GST_STATE_CHANGE_ASYNC;
2714 * gst_element_change_state:
2715 * @element: a #GstElement
2716 * @transition: the requested transition
2718 * Perform @transition on @element.
2720 * This function must be called with STATE_LOCK held and is mainly used
2723 * Returns: the #GstStateChangeReturn of the state transition.
2725 GstStateChangeReturn
2726 gst_element_change_state (GstElement * element, GstStateChange transition)
2728 GstElementClass *oclass;
2729 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2731 oclass = GST_ELEMENT_GET_CLASS (element);
2733 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2735 /* call the state change function so it can set the state */
2736 if (oclass->change_state)
2737 ret = (oclass->change_state) (element, transition);
2739 ret = GST_STATE_CHANGE_FAILURE;
2741 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2744 case GST_STATE_CHANGE_FAILURE:
2745 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2746 "have FAILURE change_state return");
2747 /* state change failure */
2748 gst_element_abort_state (element);
2750 case GST_STATE_CHANGE_ASYNC:
2754 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2755 "element will change state ASYNC");
2757 target = GST_STATE_TARGET (element);
2759 if (target > GST_STATE_READY)
2762 /* else we just continue the state change downwards */
2763 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2764 "forcing commit state %s <= %s",
2765 gst_element_state_get_name (target),
2766 gst_element_state_get_name (GST_STATE_READY));
2768 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2771 case GST_STATE_CHANGE_SUCCESS:
2772 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2773 "element changed state SUCCESS");
2774 /* we can commit the state now which will proceeed to
2776 ret = gst_element_continue_state (element, ret);
2778 case GST_STATE_CHANGE_NO_PREROLL:
2779 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2780 "element changed state NO_PREROLL");
2781 /* we can commit the state now which will proceeed to
2783 ret = gst_element_continue_state (element, ret);
2786 goto invalid_return;
2789 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2794 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2802 GST_OBJECT_LOCK (element);
2803 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2804 g_critical ("%s: unknown return value %d from a state change function",
2805 GST_ELEMENT_NAME (element), ret);
2807 /* we are in error now */
2808 ret = GST_STATE_CHANGE_FAILURE;
2809 GST_STATE_RETURN (element) = ret;
2810 GST_OBJECT_UNLOCK (element);
2816 /* gst_iterator_fold functions for pads_activate
2817 * Stop the iterator if activating one pad failed, but only if that pad
2818 * has not been removed from the element. */
2820 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2822 GstPad *pad = g_value_get_object (vpad);
2823 gboolean cont = TRUE;
2825 if (!gst_pad_set_active (pad, *active)) {
2826 if (GST_PAD_PARENT (pad) != NULL) {
2828 g_value_set_boolean (ret, FALSE);
2835 /* returns false on error or early cutout of the fold, true if all
2836 * pads in @iter were (de)activated successfully. */
2838 iterator_activate_fold_with_resync (GstIterator * iter,
2839 GstIteratorFoldFunction func, gpointer user_data)
2841 GstIteratorResult ires;
2844 /* no need to unset this later, it's just a boolean */
2845 g_value_init (&ret, G_TYPE_BOOLEAN);
2846 g_value_set_boolean (&ret, TRUE);
2849 ires = gst_iterator_fold (iter, func, &ret, user_data);
2851 case GST_ITERATOR_RESYNC:
2852 /* need to reset the result again */
2853 g_value_set_boolean (&ret, TRUE);
2854 gst_iterator_resync (iter);
2856 case GST_ITERATOR_DONE:
2857 /* all pads iterated, return collected value */
2860 /* iterator returned _ERROR or premature end with _OK,
2861 * mark an error and exit */
2862 g_value_set_boolean (&ret, FALSE);
2867 /* return collected value */
2868 return g_value_get_boolean (&ret);
2871 /* is called with STATE_LOCK
2873 * Pads are activated from source pads to sinkpads.
2876 gst_element_pads_activate (GstElement * element, gboolean active)
2881 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2882 "%s pads", active ? "activate" : "deactivate");
2884 iter = gst_element_iterate_src_pads (element);
2886 iterator_activate_fold_with_resync (iter,
2887 (GstIteratorFoldFunction) activate_pads, &active);
2888 gst_iterator_free (iter);
2889 if (G_UNLIKELY (!res))
2892 iter = gst_element_iterate_sink_pads (element);
2894 iterator_activate_fold_with_resync (iter,
2895 (GstIteratorFoldFunction) activate_pads, &active);
2896 gst_iterator_free (iter);
2897 if (G_UNLIKELY (!res))
2900 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2901 "pad %sactivation successful", active ? "" : "de");
2908 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2909 "pad %sactivation failed", active ? "" : "de");
2914 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2915 "sink pads_activate failed");
2920 /* is called with STATE_LOCK */
2921 static GstStateChangeReturn
2922 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2924 GstState state, next;
2925 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2927 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2929 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2930 next = GST_STATE_TRANSITION_NEXT (transition);
2932 /* if the element already is in the given state, we just return success */
2933 if (next == GST_STATE_VOID_PENDING || state == next)
2936 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2937 "default handler tries setting state from %s to %s (%04x)",
2938 gst_element_state_get_name (state),
2939 gst_element_state_get_name (next), transition);
2941 switch (transition) {
2942 case GST_STATE_CHANGE_NULL_TO_READY:
2944 case GST_STATE_CHANGE_READY_TO_PAUSED:
2945 if (!gst_element_pads_activate (element, TRUE)) {
2946 result = GST_STATE_CHANGE_FAILURE;
2949 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2951 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2953 case GST_STATE_CHANGE_PAUSED_TO_READY:
2954 case GST_STATE_CHANGE_READY_TO_NULL:{
2957 /* deactivate pads in both cases, since they are activated on
2958 ready->paused but the element might not have made it to paused */
2959 if (!gst_element_pads_activate (element, FALSE)) {
2960 result = GST_STATE_CHANGE_FAILURE;
2963 /* Remove all non-persistent contexts */
2964 GST_OBJECT_LOCK (element);
2965 for (l = element->contexts; l;) {
2966 GstContext *context = l->data;
2968 if (!gst_context_is_persistent (context)) {
2971 gst_context_unref (context);
2973 element->contexts = g_list_delete_link (element->contexts, l);
2979 GST_OBJECT_UNLOCK (element);
2983 /* this will catch real but unhandled state changes;
2984 * can only be caused by:
2985 * - a new state was added
2986 * - somehow the element was asked to jump across an intermediate state
2988 g_warning ("Unhandled state change from %s to %s",
2989 gst_element_state_get_name (state),
2990 gst_element_state_get_name (next));
2997 GST_OBJECT_LOCK (element);
2998 result = GST_STATE_RETURN (element);
2999 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3000 "element is already in the %s state",
3001 gst_element_state_get_name (state));
3002 GST_OBJECT_UNLOCK (element);
3009 * gst_element_get_factory:
3010 * @element: a #GstElement to request the element factory of.
3012 * Retrieves the factory that was used to create this element.
3014 * Returns: (transfer none): the #GstElementFactory used for creating this
3015 * element. no refcounting is needed.
3018 gst_element_get_factory (GstElement * element)
3020 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3022 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3026 gst_element_dispose (GObject * object)
3028 GstElement *element = GST_ELEMENT_CAST (object);
3031 GstElementClass *oclass;
3034 oclass = GST_ELEMENT_GET_CLASS (element);
3036 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3038 if (GST_STATE (element) != GST_STATE_NULL)
3041 /* start by releasing all request pads, this might also remove some dynamic
3043 walk = element->pads;
3045 GstPad *pad = GST_PAD_CAST (walk->data);
3049 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3050 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3051 == GST_PAD_REQUEST) {
3052 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3053 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3054 oclass->release_pad (element, pad);
3056 /* in case the release_pad function removed the next pad too */
3057 if (walk && g_list_position (element->pads, walk) == -1)
3058 walk = element->pads;
3061 /* remove the remaining pads */
3062 while (element->pads) {
3063 GstPad *pad = GST_PAD_CAST (element->pads->data);
3064 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3065 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3066 if (!gst_element_remove_pad (element, pad)) {
3067 /* only happens when someone unparented our pad.. */
3068 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3073 GST_OBJECT_LOCK (element);
3074 clock_p = &element->clock;
3075 bus_p = &element->bus;
3076 gst_object_replace ((GstObject **) clock_p, NULL);
3077 gst_object_replace ((GstObject **) bus_p, NULL);
3078 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3079 GST_OBJECT_UNLOCK (element);
3081 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3084 G_OBJECT_CLASS (parent_class)->dispose (object);
3093 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3095 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3097 "You need to explicitly set elements to the NULL state before\n"
3098 "dropping the final reference, to allow them to clean up.\n"
3099 "This problem may also be caused by a refcounting bug in the\n"
3100 "application or some element.\n",
3101 GST_OBJECT_NAME (element),
3102 gst_element_state_get_name (GST_STATE (element)),
3103 is_locked ? " (locked)" : "");
3109 gst_element_finalize (GObject * object)
3111 GstElement *element = GST_ELEMENT_CAST (object);
3113 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3115 g_cond_clear (&element->state_cond);
3116 g_rec_mutex_clear (&element->state_lock);
3118 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3121 G_OBJECT_CLASS (parent_class)->finalize (object);
3125 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3129 g_return_if_fail (GST_IS_ELEMENT (element));
3131 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3133 GST_OBJECT_LOCK (element);
3134 bus_p = &GST_ELEMENT_BUS (element);
3135 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3136 GST_OBJECT_UNLOCK (element);
3140 * gst_element_set_bus:
3141 * @element: a #GstElement to set the bus of.
3142 * @bus: (transfer none): the #GstBus to set.
3144 * Sets the bus of the element. Increases the refcount on the bus.
3145 * For internal use only, unless you're testing elements.
3150 gst_element_set_bus (GstElement * element, GstBus * bus)
3152 GstElementClass *oclass;
3154 g_return_if_fail (GST_IS_ELEMENT (element));
3156 oclass = GST_ELEMENT_GET_CLASS (element);
3158 if (oclass->set_bus)
3159 oclass->set_bus (element, bus);
3163 * gst_element_get_bus:
3164 * @element: a #GstElement to get the bus of.
3166 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3167 * bus for the application.
3169 * Returns: (transfer full): the element's #GstBus. unref after usage.
3174 gst_element_get_bus (GstElement * element)
3176 GstBus *result = NULL;
3178 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3180 GST_OBJECT_LOCK (element);
3181 if ((result = GST_ELEMENT_BUS (element)))
3182 gst_object_ref (result);
3183 GST_OBJECT_UNLOCK (element);
3185 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3192 gst_element_set_context_default (GstElement * element, GstContext * context)
3194 const gchar *context_type;
3197 g_return_if_fail (GST_IS_CONTEXT (context));
3198 context_type = gst_context_get_context_type (context);
3199 g_return_if_fail (context_type != NULL);
3201 GST_OBJECT_LOCK (element);
3202 for (l = element->contexts; l; l = l->next) {
3203 GstContext *tmp = l->data;
3204 const gchar *tmp_type = gst_context_get_context_type (tmp);
3206 /* Always store newest context but never replace
3207 * a persistent one by a non-persistent one */
3208 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3209 (gst_context_is_persistent (context) ||
3210 !gst_context_is_persistent (tmp))) {
3211 gst_context_replace ((GstContext **) & l->data, context);
3215 /* Not found? Add */
3218 g_list_prepend (element->contexts, gst_context_ref (context));
3220 GST_OBJECT_UNLOCK (element);
3224 * gst_element_set_context:
3225 * @element: a #GstElement to set the context of.
3226 * @context: (transfer none): the #GstContext to set.
3228 * Sets the context of the element. Increases the refcount of the context.
3233 gst_element_set_context (GstElement * element, GstContext * context)
3235 GstElementClass *oclass;
3237 g_return_if_fail (GST_IS_ELEMENT (element));
3238 g_return_if_fail (GST_IS_CONTEXT (context));
3240 oclass = GST_ELEMENT_GET_CLASS (element);
3242 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3243 "set context %p %" GST_PTR_FORMAT, context,
3244 gst_context_get_structure (context));
3246 if (oclass->set_context)
3247 oclass->set_context (element, context);
3251 * gst_element_get_contexts:
3252 * @element: a #GstElement to set the context of.
3254 * Gets the contexts set on the element.
3258 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3263 gst_element_get_contexts (GstElement * element)
3267 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3269 GST_OBJECT_LOCK (element);
3270 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3271 GST_OBJECT_UNLOCK (element);
3277 _match_context_type (GstContext * c1, const gchar * context_type)
3279 const gchar *c1_type;
3281 c1_type = gst_context_get_context_type (c1);
3283 return g_strcmp0 (c1_type, context_type);
3287 * gst_element_get_context_unlocked:
3288 * @element: a #GstElement to get the context of.
3289 * @context_type: a name of a context to retrieve
3291 * Gets the context with @context_type set on the element or NULL.
3293 * Returns: (transfer full): A #GstContext or NULL
3298 gst_element_get_context_unlocked (GstElement * element,
3299 const gchar * context_type)
3301 GstContext *ret = NULL;
3304 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3307 g_list_find_custom (element->contexts, context_type,
3308 (GCompareFunc) _match_context_type);
3309 if (node && node->data)
3310 ret = gst_context_ref (node->data);
3316 * gst_element_get_context:
3317 * @element: a #GstElement to get the context of.
3318 * @context_type: a name of a context to retrieve
3320 * Gets the context with @context_type set on the element or NULL.
3324 * Returns: (transfer full): A #GstContext or NULL
3329 gst_element_get_context (GstElement * element, const gchar * context_type)
3331 GstContext *ret = NULL;
3333 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3335 GST_OBJECT_LOCK (element);
3336 ret = gst_element_get_context_unlocked (element, context_type);
3337 GST_OBJECT_UNLOCK (element);
3343 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3344 GParamSpec * pspec, gboolean include_value)
3346 GValue val = G_VALUE_INIT;
3349 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3350 "changed, posting message with%s value", pspec->name, obj,
3351 include_value ? "" : "out");
3353 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3354 g_value_init (&val, pspec->value_type);
3355 g_object_get_property (obj, pspec->name, &val);
3360 gst_element_post_message (element,
3361 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3365 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3366 GParamSpec * pspec, gpointer user_data)
3368 gboolean include_value = GPOINTER_TO_INT (user_data);
3370 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3375 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3378 gboolean include_value = GPOINTER_TO_INT (user_data);
3380 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3385 * gst_element_add_property_notify_watch:
3386 * @element: a #GstElement to watch for property changes
3387 * @property_name: (allow-none): name of property to watch for changes, or
3388 * NULL to watch all properties
3389 * @include_value: whether to include the new property value in the message
3391 * Returns: a watch id, which can be used in connection with
3392 * gst_element_remove_property_notify_watch() to remove the watch again.
3397 gst_element_add_property_notify_watch (GstElement * element,
3398 const gchar * property_name, gboolean include_value)
3404 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3406 sep = (property_name != NULL) ? "::" : NULL;
3407 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3408 id = g_signal_connect (element, signal_name,
3409 G_CALLBACK (gst_element_property_notify_cb),
3410 GINT_TO_POINTER (include_value));
3411 g_free (signal_name);
3417 * gst_element_add_property_deep_notify_watch:
3418 * @element: a #GstElement to watch (recursively) for property changes
3419 * @property_name: (allow-none): name of property to watch for changes, or
3420 * NULL to watch all properties
3421 * @include_value: whether to include the new property value in the message
3423 * Returns: a watch id, which can be used in connection with
3424 * gst_element_remove_property_notify_watch() to remove the watch again.
3429 gst_element_add_property_deep_notify_watch (GstElement * element,
3430 const gchar * property_name, gboolean include_value)
3436 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3438 sep = (property_name != NULL) ? "::" : NULL;
3439 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3440 id = g_signal_connect (element, signal_name,
3441 G_CALLBACK (gst_element_property_deep_notify_cb),
3442 GINT_TO_POINTER (include_value));
3443 g_free (signal_name);
3449 * gst_element_remove_property_notify_watch:
3450 * @element: a #GstElement being watched for property changes
3451 * @watch_id: watch id to remove
3456 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3458 g_signal_handler_disconnect (element, watch_id);
3463 GstElement *element;
3464 GstElementCallAsyncFunc func;
3466 GDestroyNotify destroy_notify;
3467 } GstElementCallAsyncData;
3470 gst_element_call_async_func (gpointer data, gpointer user_data)
3472 GstElementCallAsyncData *async_data = data;
3474 async_data->func (async_data->element, async_data->user_data);
3475 if (async_data->destroy_notify)
3476 async_data->destroy_notify (async_data->user_data);
3477 gst_object_unref (async_data->element);
3478 g_free (async_data);
3482 * gst_element_call_async:
3483 * @element: a #GstElement
3484 * @func: Function to call asynchronously from another thread
3485 * @user_data: Data to pass to @func
3486 * @destroy_notify: GDestroyNotify for @user_data
3488 * Calls @func from another thread and passes @user_data to it. This is to be
3489 * used for cases when a state change has to be performed from a streaming
3490 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3493 * Calling those functions directly from the streaming thread will cause
3494 * deadlocks in many situations, as they might involve waiting for the
3495 * streaming thread to shut down from this very streaming thread.
3502 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3503 gpointer user_data, GDestroyNotify destroy_notify)
3505 GstElementCallAsyncData *async_data;
3507 g_return_if_fail (GST_IS_ELEMENT (element));
3509 async_data = g_new0 (GstElementCallAsyncData, 1);
3510 async_data->element = gst_object_ref (element);
3511 async_data->func = func;
3512 async_data->user_data = user_data;
3513 async_data->destroy_notify = destroy_notify;
3515 g_thread_pool_push (gst_element_pool, async_data, NULL);
3519 _priv_gst_element_cleanup (void)
3521 if (gst_element_pool) {
3522 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3523 gst_element_setup_thread_pool ();
3528 gst_make_element_message_details (const char *name, ...)
3530 GstStructure *structure;
3536 va_start (varargs, name);
3537 structure = gst_structure_new_valist ("details", name, varargs);