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_request_pad (GstElement * element, GstPadTemplate * templ,
925 const gchar * name, const GstCaps * caps)
927 GstPad *newpad = NULL;
928 GstElementClass *oclass;
930 oclass = GST_ELEMENT_GET_CLASS (element);
932 #ifndef G_DISABLE_CHECKS
933 /* Some sanity checking here */
937 /* Is this the template name? */
938 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
939 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
941 const gchar *str, *data;
944 /* Otherwise check if it's a valid name for the name template */
945 str = strchr (templ->name_template, '%');
946 g_return_val_if_fail (str != NULL, NULL);
947 g_return_val_if_fail (strncmp (templ->name_template, name,
948 str - templ->name_template) == 0, NULL);
949 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
951 data = name + (str - templ->name_template);
953 /* Can either be %s or %d or %u, do sanity checking for %d */
954 if (*(str + 1) == 'd') {
958 tmp = g_ascii_strtoll (data, &endptr, 10);
959 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
960 && *endptr == '\0', NULL);
961 } else if (*(str + 1) == 'u') {
965 tmp = g_ascii_strtoull (data, &endptr, 10);
966 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
970 pad = gst_element_get_static_pad (element, name);
972 gst_object_unref (pad);
973 /* FIXME 2.0: Change this to g_return_val_if_fail() */
974 g_critical ("Element %s already has a pad named %s, the behaviour of "
975 " gst_element_get_request_pad() for existing pads is undefined!",
976 GST_ELEMENT_NAME (element), name);
981 if (oclass->request_new_pad)
982 newpad = (oclass->request_new_pad) (element, templ, name, caps);
985 gst_object_ref (newpad);
991 * gst_element_get_request_pad:
992 * @element: a #GstElement to find a request pad of.
993 * @name: the name of the request #GstPad to retrieve.
995 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
996 * retrieves request pads. The pad should be released with
997 * gst_element_release_request_pad().
999 * This method is slower than manually getting the pad template and calling
1000 * gst_element_request_pad() if the pads should have a specific name (e.g.
1001 * @name is "src_1" instead of "src_\%u").
1003 * Returns: (transfer full) (nullable): requested #GstPad if found,
1004 * otherwise %NULL. Release after usage.
1007 gst_element_get_request_pad (GstElement * element, const gchar * name)
1009 GstPadTemplate *templ = NULL;
1011 const gchar *req_name = NULL;
1012 gboolean templ_found = FALSE;
1015 gchar *str, *endptr = NULL;
1016 GstElementClass *class;
1018 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1019 g_return_val_if_fail (name != NULL, NULL);
1021 class = GST_ELEMENT_GET_CLASS (element);
1023 /* if the name contains a %, we assume it's the complete template name. Get
1024 * the template and try to get a pad */
1025 if (strstr (name, "%")) {
1026 templ = gst_element_class_get_request_pad_template (class, name);
1031 /* there is no % in the name, try to find a matching template */
1032 list = class->padtemplates;
1033 while (!templ_found && list) {
1034 templ = (GstPadTemplate *) list->data;
1035 if (templ->presence == GST_PAD_REQUEST) {
1036 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1037 templ->name_template);
1038 /* see if we find an exact match */
1039 if (strcmp (name, templ->name_template) == 0) {
1044 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1045 and %d and %u, occurring at the end of the name_template, are the only
1047 else if ((str = strchr (templ->name_template, '%'))
1048 && strncmp (templ->name_template, name,
1049 str - templ->name_template) == 0
1050 && strlen (name) > str - templ->name_template) {
1051 data = name + (str - templ->name_template);
1052 if (*(str + 1) == 'd') {
1056 tmp = strtol (data, &endptr, 10);
1057 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1063 } else if (*(str + 1) == 'u') {
1067 tmp = strtoul (data, &endptr, 10);
1068 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1088 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1094 * gst_element_request_pad: (virtual request_new_pad)
1095 * @element: a #GstElement to find a request pad of.
1096 * @templ: a #GstPadTemplate of which we want a pad of.
1097 * @name: (transfer none) (allow-none): the name of the request #GstPad
1098 * to retrieve. Can be %NULL.
1099 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1100 * request. Can be %NULL.
1102 * Retrieves a request pad from the element according to the provided template.
1103 * Pad templates can be looked up using
1104 * gst_element_factory_get_static_pad_templates().
1106 * The pad should be released with gst_element_release_request_pad().
1108 * Returns: (transfer full) (nullable): requested #GstPad if found,
1109 * otherwise %NULL. Release after usage.
1112 gst_element_request_pad (GstElement * element,
1113 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1115 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1116 g_return_val_if_fail (templ != NULL, NULL);
1117 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1119 return _gst_element_request_pad (element, templ, name, caps);
1122 static GstIterator *
1123 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1125 GstIterator *result;
1127 GST_OBJECT_LOCK (element);
1128 result = gst_iterator_new_list (GST_TYPE_PAD,
1129 GST_OBJECT_GET_LOCK (element),
1130 &element->pads_cookie, padlist, (GObject *) element, NULL);
1131 GST_OBJECT_UNLOCK (element);
1137 * gst_element_iterate_pads:
1138 * @element: a #GstElement to iterate pads of.
1140 * Retrieves an iterator of @element's pads. The iterator should
1141 * be freed after usage. Also more specialized iterators exists such as
1142 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1144 * The order of pads returned by the iterator will be the order in which
1145 * the pads were added to the element.
1147 * Returns: (transfer full): the #GstIterator of #GstPad.
1152 gst_element_iterate_pads (GstElement * element)
1154 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1156 return gst_element_iterate_pad_list (element, &element->pads);
1160 * gst_element_iterate_src_pads:
1161 * @element: a #GstElement.
1163 * Retrieves an iterator of @element's source pads.
1165 * The order of pads returned by the iterator will be the order in which
1166 * the pads were added to the element.
1168 * Returns: (transfer full): the #GstIterator of #GstPad.
1173 gst_element_iterate_src_pads (GstElement * element)
1175 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1177 return gst_element_iterate_pad_list (element, &element->srcpads);
1181 * gst_element_iterate_sink_pads:
1182 * @element: a #GstElement.
1184 * Retrieves an iterator of @element's 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_sink_pads (GstElement * element)
1196 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1198 return gst_element_iterate_pad_list (element, &element->sinkpads);
1202 * gst_element_class_add_pad_template:
1203 * @klass: the #GstElementClass to add the pad template to.
1204 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1206 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1207 * functions of classes. If a pad template with the same name as an already
1208 * existing one is added the old one is replaced by the new one.
1212 gst_element_class_add_pad_template (GstElementClass * klass,
1213 GstPadTemplate * templ)
1215 GList *template_list = klass->padtemplates;
1217 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1218 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1220 /* If we already have a pad template with the same name replace the
1222 while (template_list) {
1223 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1225 /* Found pad with the same name, replace and return */
1226 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1227 gst_object_unref (padtempl);
1228 template_list->data = templ;
1231 template_list = g_list_next (template_list);
1234 /* Take ownership of the floating ref */
1235 gst_object_ref_sink (templ);
1237 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1238 klass->numpadtemplates++;
1242 * gst_element_class_add_static_pad_template:
1243 * @klass: the #GstElementClass to add the pad template to.
1244 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1246 * Adds a pad template to an element class based on the static pad template
1247 * @templ. This is mainly used in the _class_init functions of element
1248 * implementations. If a pad template with the same name already exists,
1249 * the old one is replaced by the new one.
1254 gst_element_class_add_static_pad_template (GstElementClass * klass,
1255 GstStaticPadTemplate * static_templ)
1257 gst_element_class_add_pad_template (klass,
1258 gst_static_pad_template_get (static_templ));
1262 * gst_element_class_add_metadata:
1263 * @klass: class to set metadata for
1264 * @key: the key to set
1265 * @value: the value to set
1267 * Set @key with @value as metadata in @klass.
1270 gst_element_class_add_metadata (GstElementClass * klass,
1271 const gchar * key, const gchar * value)
1273 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1274 g_return_if_fail (key != NULL);
1275 g_return_if_fail (value != NULL);
1277 gst_structure_set ((GstStructure *) klass->metadata,
1278 key, G_TYPE_STRING, value, NULL);
1282 * gst_element_class_add_static_metadata:
1283 * @klass: class to set metadata for
1284 * @key: the key to set
1285 * @value: the value to set
1287 * Set @key with @value as metadata in @klass.
1289 * Same as gst_element_class_add_metadata(), but @value must be a static string
1290 * or an inlined string, as it will not be copied. (GStreamer plugins will
1291 * be made resident once loaded, so this function can be used even from
1292 * dynamically loaded plugins.)
1295 gst_element_class_add_static_metadata (GstElementClass * klass,
1296 const gchar * key, const gchar * value)
1298 GValue val = G_VALUE_INIT;
1300 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1301 g_return_if_fail (key != NULL);
1302 g_return_if_fail (value != NULL);
1304 g_value_init (&val, G_TYPE_STRING);
1305 g_value_set_static_string (&val, value);
1306 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1310 * gst_element_class_set_metadata:
1311 * @klass: class to set metadata for
1312 * @longname: The long English name of the element. E.g. "File Sink"
1313 * @classification: String describing the type of element, as an unordered list
1314 * separated with slashes ('/'). See draft-klass.txt of the design docs
1315 * for more details and common types. E.g: "Sink/File"
1316 * @description: Sentence describing the purpose of the element.
1317 * E.g: "Write stream to a file"
1318 * @author: Name and contact details of the author(s). Use \n to separate
1319 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1321 * Sets the detailed information for a #GstElementClass.
1322 * <note>This function is for use in _class_init functions only.</note>
1325 gst_element_class_set_metadata (GstElementClass * klass,
1326 const gchar * longname, const gchar * classification,
1327 const gchar * description, const gchar * author)
1329 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1330 g_return_if_fail (longname != NULL && *longname != '\0');
1331 g_return_if_fail (classification != NULL && *classification != '\0');
1332 g_return_if_fail (description != NULL && *description != '\0');
1333 g_return_if_fail (author != NULL && *author != '\0');
1335 gst_structure_id_set ((GstStructure *) klass->metadata,
1336 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1337 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1338 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1339 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1343 * gst_element_class_set_static_metadata:
1344 * @klass: class to set metadata for
1345 * @longname: The long English name of the element. E.g. "File Sink"
1346 * @classification: String describing the type of element, as an unordered list
1347 * separated with slashes ('/'). See draft-klass.txt of the design docs
1348 * for more details and common types. E.g: "Sink/File"
1349 * @description: Sentence describing the purpose of the element.
1350 * E.g: "Write stream to a file"
1351 * @author: Name and contact details of the author(s). Use \n to separate
1352 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1354 * Sets the detailed information for a #GstElementClass.
1355 * <note>This function is for use in _class_init functions only.</note>
1357 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1358 * @description, and @author must be static strings or inlined strings, as
1359 * they will not be copied. (GStreamer plugins will be made resident once
1360 * loaded, so this function can be used even from dynamically loaded plugins.)
1363 gst_element_class_set_static_metadata (GstElementClass * klass,
1364 const gchar * longname, const gchar * classification,
1365 const gchar * description, const gchar * author)
1367 GstStructure *s = (GstStructure *) klass->metadata;
1368 GValue val = G_VALUE_INIT;
1370 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1371 g_return_if_fail (longname != NULL && *longname != '\0');
1372 g_return_if_fail (classification != NULL && *classification != '\0');
1373 g_return_if_fail (description != NULL && *description != '\0');
1374 g_return_if_fail (author != NULL && *author != '\0');
1376 g_value_init (&val, G_TYPE_STRING);
1378 g_value_set_static_string (&val, longname);
1379 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1381 g_value_set_static_string (&val, classification);
1382 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1384 g_value_set_static_string (&val, description);
1385 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1388 g_value_set_static_string (&val, author);
1389 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1393 * gst_element_class_get_metadata:
1394 * @klass: class to get metadata for
1395 * @key: the key to get
1397 * Get metadata with @key in @klass.
1399 * Returns: the metadata for @key.
1402 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1404 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1405 g_return_val_if_fail (key != NULL, NULL);
1407 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1411 * gst_element_class_get_pad_template_list:
1412 * @element_class: a #GstElementClass to get pad templates of.
1414 * Retrieves a list of the pad templates associated with @element_class. The
1415 * list must not be modified by the calling code.
1416 * <note>If you use this function in the #GInstanceInitFunc of an object class
1417 * that has subclasses, make sure to pass the g_class parameter of the
1418 * #GInstanceInitFunc here.</note>
1420 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1424 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1426 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1428 return element_class->padtemplates;
1432 * gst_element_class_get_pad_template:
1433 * @element_class: a #GstElementClass to get the pad template of.
1434 * @name: the name of the #GstPadTemplate to get.
1436 * Retrieves a padtemplate from @element_class with the given name.
1437 * <note>If you use this function in the #GInstanceInitFunc of an object class
1438 * that has subclasses, make sure to pass the g_class parameter of the
1439 * #GInstanceInitFunc here.</note>
1441 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1442 * given name, or %NULL if none was found. No unreferencing is
1446 gst_element_class_get_pad_template (GstElementClass *
1447 element_class, const gchar * name)
1451 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1452 g_return_val_if_fail (name != NULL, NULL);
1454 padlist = element_class->padtemplates;
1457 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1459 if (strcmp (padtempl->name_template, name) == 0)
1462 padlist = g_list_next (padlist);
1468 static GstPadTemplate *
1469 gst_element_class_get_request_pad_template (GstElementClass *
1470 element_class, const gchar * name)
1472 GstPadTemplate *tmpl;
1474 tmpl = gst_element_class_get_pad_template (element_class, name);
1475 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1481 /* get a random pad on element of the given direction.
1482 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1485 gst_element_get_random_pad (GstElement * element,
1486 gboolean need_linked, GstPadDirection dir)
1488 GstPad *result = NULL;
1491 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1495 GST_OBJECT_LOCK (element);
1496 pads = element->srcpads;
1499 GST_OBJECT_LOCK (element);
1500 pads = element->sinkpads;
1503 goto wrong_direction;
1505 for (; pads; pads = g_list_next (pads)) {
1506 GstPad *pad = GST_PAD_CAST (pads->data);
1508 GST_OBJECT_LOCK (pad);
1509 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1510 GST_DEBUG_PAD_NAME (pad));
1512 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1513 /* if we require a linked pad, and it is not linked, continue the
1515 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1516 GST_DEBUG_PAD_NAME (pad));
1517 GST_OBJECT_UNLOCK (pad);
1520 /* found a pad, stop search */
1521 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1522 GST_DEBUG_PAD_NAME (pad));
1523 GST_OBJECT_UNLOCK (pad);
1529 gst_object_ref (result);
1531 GST_OBJECT_UNLOCK (element);
1535 /* ERROR handling */
1538 g_warning ("unknown pad direction %d", dir);
1544 gst_element_default_send_event (GstElement * element, GstEvent * event)
1546 gboolean result = FALSE;
1549 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1550 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1551 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1554 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1555 "pushing %s event to random %s pad %s:%s",
1556 GST_EVENT_TYPE_NAME (event),
1557 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1558 GST_DEBUG_PAD_NAME (pad));
1560 result = gst_pad_send_event (pad, event);
1561 gst_object_unref (pad);
1563 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1564 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1565 gst_event_unref (event);
1571 * gst_element_send_event:
1572 * @element: a #GstElement to send the event to.
1573 * @event: (transfer full): the #GstEvent to send to the element.
1575 * Sends an event to an element. If the element doesn't implement an
1576 * event handler, the event will be pushed on a random linked sink pad for
1577 * downstream events or a random linked source pad for upstream events.
1579 * This function takes ownership of the provided event so you should
1580 * gst_event_ref() it if you want to reuse the event after this call.
1584 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1585 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1588 gst_element_send_event (GstElement * element, GstEvent * event)
1590 GstElementClass *oclass;
1591 gboolean result = FALSE;
1593 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1594 g_return_val_if_fail (event != NULL, FALSE);
1596 oclass = GST_ELEMENT_GET_CLASS (element);
1598 GST_STATE_LOCK (element);
1599 if (oclass->send_event) {
1600 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1601 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1602 result = oclass->send_event (element, event);
1604 gst_event_unref (event);
1606 GST_STATE_UNLOCK (element);
1613 * @element: a #GstElement to send the event to.
1614 * @rate: The new playback rate
1615 * @format: The format of the seek values
1616 * @flags: The optional seek flags.
1617 * @start_type: The type and flags for the new start position
1618 * @start: The value of the new start position
1619 * @stop_type: The type and flags for the new stop position
1620 * @stop: The value of the new stop position
1622 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1623 * the parameters. The seek event is sent to the element using
1624 * gst_element_send_event().
1628 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1629 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1632 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1633 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1634 GstSeekType stop_type, gint64 stop)
1639 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1642 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1644 result = gst_element_send_event (element, event);
1650 gst_element_default_query (GstElement * element, GstQuery * query)
1652 gboolean result = FALSE;
1655 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1657 result = gst_pad_query (pad, query);
1659 gst_object_unref (pad);
1661 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1663 GstPad *peer = gst_pad_get_peer (pad);
1666 result = gst_pad_query (peer, query);
1668 gst_object_unref (peer);
1670 gst_object_unref (pad);
1677 * gst_element_query:
1678 * @element: a #GstElement to perform the query on.
1679 * @query: (transfer none): the #GstQuery.
1681 * Performs a query on the given element.
1683 * For elements that don't implement a query handler, this function
1684 * forwards the query to a random srcpad or to the peer of a
1685 * random linked sinkpad of this element.
1687 * Please note that some queries might need a running pipeline to work.
1689 * Returns: %TRUE if the query could be performed.
1694 gst_element_query (GstElement * element, GstQuery * query)
1696 GstElementClass *klass;
1697 gboolean res = FALSE;
1699 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1700 g_return_val_if_fail (query != NULL, FALSE);
1702 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1704 klass = GST_ELEMENT_GET_CLASS (element);
1706 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1707 GST_ELEMENT_NAME (element));
1708 res = klass->query (element, query);
1711 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1716 gst_element_post_message_default (GstElement * element, GstMessage * message)
1719 gboolean result = FALSE;
1721 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1722 g_return_val_if_fail (message != NULL, FALSE);
1724 GST_OBJECT_LOCK (element);
1727 if (G_UNLIKELY (bus == NULL))
1730 gst_object_ref (bus);
1731 GST_OBJECT_UNLOCK (element);
1733 /* we release the element lock when posting the message so that any
1734 * (synchronous) message handlers can operate on the element */
1735 result = gst_bus_post (bus, message);
1736 gst_object_unref (bus);
1743 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1744 "not posting message %p: no bus", message);
1745 GST_OBJECT_UNLOCK (element);
1746 gst_message_unref (message);
1752 * gst_element_post_message:
1753 * @element: a #GstElement posting the message
1754 * @message: (transfer full): a #GstMessage to post
1756 * Post a message on the element's #GstBus. This function takes ownership of the
1757 * message; if you want to access the message after this call, you should add an
1758 * additional reference before calling.
1760 * Returns: %TRUE if the message was successfully posted. The function returns
1761 * %FALSE if the element did not have a bus.
1766 gst_element_post_message (GstElement * element, GstMessage * message)
1768 GstElementClass *klass;
1769 gboolean res = FALSE;
1771 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1772 g_return_val_if_fail (message != NULL, FALSE);
1774 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1776 klass = GST_ELEMENT_GET_CLASS (element);
1777 if (klass->post_message)
1778 res = klass->post_message (element, message);
1780 gst_message_unref (message);
1782 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1787 * _gst_element_error_printf:
1788 * @format: (allow-none): the printf-like format to use, or %NULL
1790 * This function is only used internally by the gst_element_error() macro.
1792 * Returns: (transfer full) (nullable): a newly allocated string, or
1793 * %NULL if the format was %NULL or ""
1798 _gst_element_error_printf (const gchar * format, ...)
1809 va_start (args, format);
1811 len = __gst_vasprintf (&buffer, format, args);
1822 * gst_element_message_full_with_details:
1823 * @element: a #GstElement to send message from
1824 * @type: the #GstMessageType
1825 * @domain: the GStreamer GError domain this message belongs to
1826 * @code: the GError code belonging to the domain
1827 * @text: (allow-none) (transfer full): an allocated text string to be used
1828 * as a replacement for the default message connected to code,
1830 * @debug: (allow-none) (transfer full): an allocated debug message to be
1831 * used as a replacement for the default debugging information,
1833 * @file: the source code file where the error was generated
1834 * @function: the source code function where the error was generated
1835 * @line: the source code line where the error was generated
1836 * @structure:(transfer full): optional details structure
1838 * Post an error, warning or info message on the bus from inside an element.
1840 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1841 * #GST_MESSAGE_INFO.
1847 void gst_element_message_full_with_details
1848 (GstElement * element, GstMessageType type,
1849 GQuark domain, gint code, gchar * text,
1850 gchar * debug, const gchar * file, const gchar * function, gint line,
1851 GstStructure * structure)
1853 GError *gerror = NULL;
1857 gboolean has_debug = TRUE;
1858 GstMessage *message = NULL;
1861 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1862 g_return_if_fail (GST_IS_ELEMENT (element));
1863 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1864 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1866 /* check if we send the given text or the default error text */
1867 if ((text == NULL) || (text[0] == 0)) {
1868 /* text could have come from g_strdup_printf (""); */
1870 sent_text = gst_error_get_message (domain, code);
1874 /* construct a sent_debug with extra information from source */
1875 if ((debug == NULL) || (debug[0] == 0)) {
1876 /* debug could have come from g_strdup_printf (""); */
1880 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1882 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1883 file, line, function, name, debug);
1885 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1886 file, line, function, name);
1890 /* create gerror and post message */
1891 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1893 gerror = g_error_new_literal (domain, code, sent_text);
1896 case GST_MESSAGE_ERROR:
1898 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1899 sent_debug, structure);
1901 case GST_MESSAGE_WARNING:
1903 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1904 gerror, sent_debug, structure);
1906 case GST_MESSAGE_INFO:
1908 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1909 sent_debug, structure);
1912 g_assert_not_reached ();
1916 gst_element_post_message (element, message);
1918 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1919 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1922 g_error_free (gerror);
1923 g_free (sent_debug);
1928 * gst_element_message_full:
1929 * @element: a #GstElement to send message from
1930 * @type: the #GstMessageType
1931 * @domain: the GStreamer GError domain this message belongs to
1932 * @code: the GError code belonging to the domain
1933 * @text: (allow-none) (transfer full): an allocated text string to be used
1934 * as a replacement for the default message connected to code,
1936 * @debug: (allow-none) (transfer full): an allocated debug message to be
1937 * used as a replacement for the default debugging information,
1939 * @file: the source code file where the error was generated
1940 * @function: the source code function where the error was generated
1941 * @line: the source code line where the error was generated
1943 * Post an error, warning or info message on the bus from inside an element.
1945 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1946 * #GST_MESSAGE_INFO.
1950 void gst_element_message_full
1951 (GstElement * element, GstMessageType type,
1952 GQuark domain, gint code, gchar * text,
1953 gchar * debug, const gchar * file, const gchar * function, gint line)
1955 gst_element_message_full_with_details (element, type, domain, code, text,
1956 debug, file, function, line, NULL);
1960 * gst_element_is_locked_state:
1961 * @element: a #GstElement.
1963 * Checks if the state of an element is locked.
1964 * If the state of an element is locked, state changes of the parent don't
1965 * affect the element.
1966 * This way you can leave currently unused elements inside bins. Just lock their
1967 * state before changing the state from #GST_STATE_NULL.
1971 * Returns: %TRUE, if the element's state is locked.
1974 gst_element_is_locked_state (GstElement * element)
1978 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1980 GST_OBJECT_LOCK (element);
1981 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1982 GST_OBJECT_UNLOCK (element);
1988 * gst_element_set_locked_state:
1989 * @element: a #GstElement
1990 * @locked_state: %TRUE to lock the element's state
1992 * Locks the state of an element, so state changes of the parent don't affect
1993 * this element anymore.
1997 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
1998 * or the elements state-locking needed no change.
2001 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2005 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2007 GST_OBJECT_LOCK (element);
2008 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2010 if (G_UNLIKELY (old == locked_state))
2014 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2015 GST_ELEMENT_NAME (element));
2016 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2018 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2019 GST_ELEMENT_NAME (element));
2020 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2022 GST_OBJECT_UNLOCK (element);
2028 GST_CAT_DEBUG (GST_CAT_STATES,
2029 "elements %s was already in locked state %d",
2030 GST_ELEMENT_NAME (element), old);
2031 GST_OBJECT_UNLOCK (element);
2038 * gst_element_sync_state_with_parent:
2039 * @element: a #GstElement.
2041 * Tries to change the state of the element to the same as its parent.
2042 * If this function returns %FALSE, the state of element is undefined.
2044 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2049 gst_element_sync_state_with_parent (GstElement * element)
2053 GstStateChangeReturn ret;
2055 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2057 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2058 GstState parent_current, parent_pending;
2060 GST_OBJECT_LOCK (parent);
2061 parent_current = GST_STATE (parent);
2062 parent_pending = GST_STATE_PENDING (parent);
2063 GST_OBJECT_UNLOCK (parent);
2065 /* set to pending if there is one, else we set it to the current state of
2067 if (parent_pending != GST_STATE_VOID_PENDING)
2068 target = parent_pending;
2070 target = parent_current;
2072 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2073 "syncing state (%s) to parent %s %s (%s, %s)",
2074 gst_element_state_get_name (GST_STATE (element)),
2075 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2076 gst_element_state_get_name (parent_current),
2077 gst_element_state_get_name (parent_pending));
2079 ret = gst_element_set_state (element, target);
2080 if (ret == GST_STATE_CHANGE_FAILURE)
2083 gst_object_unref (parent);
2087 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2094 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2095 "syncing state failed (%s)",
2096 gst_element_state_change_return_get_name (ret));
2097 gst_object_unref (parent);
2103 static GstStateChangeReturn
2104 gst_element_get_state_func (GstElement * element,
2105 GstState * state, GstState * pending, GstClockTime timeout)
2107 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2108 GstState old_pending;
2110 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2111 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2113 GST_OBJECT_LOCK (element);
2114 ret = GST_STATE_RETURN (element);
2115 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2116 gst_element_state_change_return_get_name (ret));
2118 /* we got an error, report immediately */
2119 if (ret == GST_STATE_CHANGE_FAILURE)
2122 /* we got no_preroll, report immediately */
2123 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2126 /* no need to wait async if we are not async */
2127 if (ret != GST_STATE_CHANGE_ASYNC)
2130 old_pending = GST_STATE_PENDING (element);
2131 if (old_pending != GST_STATE_VOID_PENDING) {
2135 /* get cookie to detect state changes during waiting */
2136 cookie = element->state_cookie;
2138 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2139 "waiting for element to commit state");
2141 /* we have a pending state change, wait for it to complete */
2142 if (timeout != GST_CLOCK_TIME_NONE) {
2144 /* make timeout absolute */
2145 end_time = g_get_monotonic_time () + (timeout / 1000);
2146 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2148 GST_STATE_WAIT (element);
2153 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2154 /* timeout triggered */
2155 ret = GST_STATE_CHANGE_ASYNC;
2157 if (cookie != element->state_cookie)
2160 /* could be success or failure */
2161 if (old_pending == GST_STATE (element)) {
2162 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2163 ret = GST_STATE_CHANGE_SUCCESS;
2165 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2166 ret = GST_STATE_CHANGE_FAILURE;
2169 /* if nothing is pending anymore we can return SUCCESS */
2170 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2171 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2172 ret = GST_STATE_CHANGE_SUCCESS;
2178 *state = GST_STATE (element);
2180 *pending = GST_STATE_PENDING (element);
2182 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2183 "state current: %s, pending: %s, result: %s",
2184 gst_element_state_get_name (GST_STATE (element)),
2185 gst_element_state_get_name (GST_STATE_PENDING (element)),
2186 gst_element_state_change_return_get_name (ret));
2187 GST_OBJECT_UNLOCK (element);
2194 *state = GST_STATE_VOID_PENDING;
2196 *pending = GST_STATE_VOID_PENDING;
2198 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2200 GST_OBJECT_UNLOCK (element);
2202 return GST_STATE_CHANGE_FAILURE;
2207 * gst_element_get_state:
2208 * @element: a #GstElement to get the state of.
2209 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2211 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2212 * state. Can be %NULL.
2213 * @timeout: a #GstClockTime to specify the timeout for an async
2214 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2216 * Gets the state of the element.
2218 * For elements that performed an ASYNC state change, as reported by
2219 * gst_element_set_state(), this function will block up to the
2220 * specified timeout value for the state change to complete.
2221 * If the element completes the state change or goes into
2222 * an error, this function returns immediately with a return value of
2223 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2225 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2226 * returns the current and pending state immediately.
2228 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2229 * successfully changed its state but is not able to provide data yet.
2230 * This mostly happens for live sources that only produce data in
2231 * %GST_STATE_PLAYING. While the state change return is equivalent to
2232 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2233 * some sink elements might not be able to complete their state change because
2234 * an element is not producing data to complete the preroll. When setting the
2235 * element to playing, the preroll will complete and playback will start.
2237 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2238 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2239 * element is still performing a state change or
2240 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2244 GstStateChangeReturn
2245 gst_element_get_state (GstElement * element,
2246 GstState * state, GstState * pending, GstClockTime timeout)
2248 GstElementClass *oclass;
2249 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2251 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2253 oclass = GST_ELEMENT_GET_CLASS (element);
2255 if (oclass->get_state)
2256 result = (oclass->get_state) (element, state, pending, timeout);
2262 * gst_element_abort_state:
2263 * @element: a #GstElement to abort the state of.
2265 * Abort the state change of the element. This function is used
2266 * by elements that do asynchronous state changes and find out
2267 * something is wrong.
2269 * This function should be called with the STATE_LOCK held.
2274 gst_element_abort_state (GstElement * element)
2278 #ifndef GST_DISABLE_GST_DEBUG
2282 g_return_if_fail (GST_IS_ELEMENT (element));
2284 GST_OBJECT_LOCK (element);
2285 pending = GST_STATE_PENDING (element);
2287 if (pending == GST_STATE_VOID_PENDING ||
2288 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2289 goto nothing_aborted;
2291 #ifndef GST_DISABLE_GST_DEBUG
2292 old_state = GST_STATE (element);
2294 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2295 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2296 gst_element_state_get_name (pending));
2300 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2302 GST_STATE_BROADCAST (element);
2303 GST_OBJECT_UNLOCK (element);
2309 GST_OBJECT_UNLOCK (element);
2314 /* Not static because GstBin has manual state handling too */
2316 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2317 GstState newstate, GstState pending)
2319 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2320 GstMessage *message;
2322 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2323 "notifying about state-changed %s to %s (%s pending)",
2324 gst_element_state_get_name (oldstate),
2325 gst_element_state_get_name (newstate),
2326 gst_element_state_get_name (pending));
2328 if (klass->state_changed)
2329 klass->state_changed (element, oldstate, newstate, pending);
2331 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2332 oldstate, newstate, pending);
2333 gst_element_post_message (element, message);
2337 * gst_element_continue_state:
2338 * @element: a #GstElement to continue the state change of.
2339 * @ret: The previous state return value
2341 * Commit the state change of the element and proceed to the next
2342 * pending state if any. This function is used
2343 * by elements that do asynchronous state changes.
2344 * The core will normally call this method automatically when an
2345 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2347 * If after calling this method the element still has not reached
2348 * the pending state, the next state change is performed.
2350 * This method is used internally and should normally not be called by plugins
2353 * Returns: The result of the commit state change.
2357 GstStateChangeReturn
2358 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2360 GstStateChangeReturn old_ret;
2361 GstState old_state, old_next;
2362 GstState current, next, pending;
2363 GstStateChange transition;
2365 GST_OBJECT_LOCK (element);
2366 old_ret = GST_STATE_RETURN (element);
2367 GST_STATE_RETURN (element) = ret;
2368 pending = GST_STATE_PENDING (element);
2370 /* check if there is something to commit */
2371 if (pending == GST_STATE_VOID_PENDING)
2372 goto nothing_pending;
2374 old_state = GST_STATE (element);
2375 /* this is the state we should go to next */
2376 old_next = GST_STATE_NEXT (element);
2377 /* update current state */
2378 current = GST_STATE (element) = old_next;
2380 /* see if we reached the final state */
2381 if (pending == current)
2384 next = GST_STATE_GET_NEXT (current, pending);
2385 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2387 GST_STATE_NEXT (element) = next;
2389 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2390 GST_OBJECT_UNLOCK (element);
2392 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2393 "committing state from %s to %s, pending %s, next %s",
2394 gst_element_state_get_name (old_state),
2395 gst_element_state_get_name (old_next),
2396 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2398 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2400 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2401 "continue state change %s to %s, final %s",
2402 gst_element_state_get_name (current),
2403 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2405 ret = gst_element_change_state (element, transition);
2411 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2412 GST_OBJECT_UNLOCK (element);
2417 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2418 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2420 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2421 "completed state change to %s", gst_element_state_get_name (pending));
2422 GST_OBJECT_UNLOCK (element);
2424 /* don't post silly messages with the same state. This can happen
2425 * when an element state is changed to what it already was. For bins
2426 * this can be the result of a lost state, which we check with the
2427 * previous return value.
2428 * We do signal the cond though as a _get_state() might be blocking
2430 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2431 _priv_gst_element_state_changed (element, old_state, old_next,
2432 GST_STATE_VOID_PENDING);
2434 GST_STATE_BROADCAST (element);
2441 * gst_element_lost_state:
2442 * @element: a #GstElement the state is lost of
2444 * Brings the element to the lost state. The current state of the
2445 * element is copied to the pending state so that any call to
2446 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2448 * An ASYNC_START message is posted. If the element was PLAYING, it will
2449 * go to PAUSED. The element will be restored to its PLAYING state by
2450 * the parent pipeline when it prerolls again.
2452 * This is mostly used for elements that lost their preroll buffer
2453 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2454 * they will go to their pending state again when a new preroll buffer is
2455 * queued. This function can only be called when the element is currently
2456 * not in error or an async state change.
2458 * This function is used internally and should normally not be called from
2459 * plugins or applications.
2462 gst_element_lost_state (GstElement * element)
2464 GstState old_state, new_state;
2465 GstMessage *message;
2467 g_return_if_fail (GST_IS_ELEMENT (element));
2469 GST_OBJECT_LOCK (element);
2470 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2473 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2474 goto only_async_start;
2476 old_state = GST_STATE (element);
2478 /* when we were PLAYING, the new state is PAUSED. We will also not
2479 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2480 * when we preroll. */
2481 if (old_state > GST_STATE_PAUSED)
2482 new_state = GST_STATE_PAUSED;
2484 new_state = old_state;
2486 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2487 "lost state of %s to %s", gst_element_state_get_name (old_state),
2488 gst_element_state_get_name (new_state));
2490 GST_STATE (element) = new_state;
2491 GST_STATE_NEXT (element) = new_state;
2492 GST_STATE_PENDING (element) = new_state;
2493 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2494 GST_OBJECT_UNLOCK (element);
2496 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2498 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2499 gst_element_post_message (element, message);
2505 GST_OBJECT_UNLOCK (element);
2510 GST_OBJECT_UNLOCK (element);
2512 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2513 gst_element_post_message (element, message);
2519 * gst_element_set_state:
2520 * @element: a #GstElement to change state of.
2521 * @state: the element's new #GstState.
2523 * Sets the state of the element. This function will try to set the
2524 * requested state by going through all the intermediary states and calling
2525 * the class's state change function for each.
2527 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2528 * element will perform the remainder of the state change asynchronously in
2530 * An application can use gst_element_get_state() to wait for the completion
2531 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2532 * %GST_MESSAGE_STATE_CHANGED on the bus.
2534 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2535 * #GST_STATE_CHANGE_ASYNC.
2537 * Returns: Result of the state change using #GstStateChangeReturn.
2541 GstStateChangeReturn
2542 gst_element_set_state (GstElement * element, GstState state)
2544 GstElementClass *oclass;
2545 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2547 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2549 oclass = GST_ELEMENT_GET_CLASS (element);
2551 if (oclass->set_state)
2552 result = (oclass->set_state) (element, state);
2558 * default set state function, calculates the next state based
2559 * on current state and calls the change_state function
2561 static GstStateChangeReturn
2562 gst_element_set_state_func (GstElement * element, GstState state)
2564 GstState current, next, old_pending;
2565 GstStateChangeReturn ret;
2566 GstStateChange transition;
2567 GstStateChangeReturn old_ret;
2569 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2571 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2572 gst_element_state_get_name (state));
2574 /* state lock is taken to protect the set_state() and get_state()
2575 * procedures, it does not lock any variables. */
2576 GST_STATE_LOCK (element);
2578 /* now calculate how to get to the new state */
2579 GST_OBJECT_LOCK (element);
2580 old_ret = GST_STATE_RETURN (element);
2581 /* previous state change returned an error, remove all pending
2582 * and next states */
2583 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2584 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2585 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2586 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2589 current = GST_STATE (element);
2590 next = GST_STATE_NEXT (element);
2591 old_pending = GST_STATE_PENDING (element);
2593 /* this is the (new) state we should go to. TARGET is the last state we set on
2595 if (state != GST_STATE_TARGET (element)) {
2596 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2597 "setting target state to %s", gst_element_state_get_name (state));
2598 GST_STATE_TARGET (element) = state;
2599 /* increment state cookie so that we can track each state change. We only do
2600 * this if this is actually a new state change. */
2601 element->state_cookie++;
2603 GST_STATE_PENDING (element) = state;
2605 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2606 "current %s, old_pending %s, next %s, old return %s",
2607 gst_element_state_get_name (current),
2608 gst_element_state_get_name (old_pending),
2609 gst_element_state_get_name (next),
2610 gst_element_state_change_return_get_name (old_ret));
2612 /* if the element was busy doing a state change, we just update the
2613 * target state, it'll get to it async then. */
2614 if (old_pending != GST_STATE_VOID_PENDING) {
2615 /* upwards state change will happen ASYNC */
2616 if (old_pending <= state)
2618 /* element is going to this state already */
2619 else if (next == state)
2621 /* element was performing an ASYNC upward state change and
2622 * we request to go downward again. Start from the next pending
2624 else if (next > state
2625 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2629 next = GST_STATE_GET_NEXT (current, state);
2630 /* now we store the next state */
2631 GST_STATE_NEXT (element) = next;
2632 /* mark busy, we need to check that there is actually a state change
2633 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2634 * the default element change_state function has no way to know what the
2635 * old value was... could consider this a FIXME...*/
2636 if (current != next)
2637 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2639 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2641 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2642 "%s: setting state from %s to %s",
2643 (next != state ? "intermediate" : "final"),
2644 gst_element_state_get_name (current), gst_element_state_get_name (next));
2646 /* now signal any waiters, they will error since the cookie was incremented */
2647 GST_STATE_BROADCAST (element);
2649 GST_OBJECT_UNLOCK (element);
2651 ret = gst_element_change_state (element, transition);
2653 GST_STATE_UNLOCK (element);
2655 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2656 gst_element_state_change_return_get_name (ret));
2662 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2663 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2664 "element was busy with async state change");
2665 GST_OBJECT_UNLOCK (element);
2667 GST_STATE_UNLOCK (element);
2669 return GST_STATE_CHANGE_ASYNC;
2674 * gst_element_change_state:
2675 * @element: a #GstElement
2676 * @transition: the requested transition
2678 * Perform @transition on @element.
2680 * This function must be called with STATE_LOCK held and is mainly used
2683 * Returns: the #GstStateChangeReturn of the state transition.
2685 GstStateChangeReturn
2686 gst_element_change_state (GstElement * element, GstStateChange transition)
2688 GstElementClass *oclass;
2689 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2691 oclass = GST_ELEMENT_GET_CLASS (element);
2693 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2695 /* call the state change function so it can set the state */
2696 if (oclass->change_state)
2697 ret = (oclass->change_state) (element, transition);
2699 ret = GST_STATE_CHANGE_FAILURE;
2701 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2704 case GST_STATE_CHANGE_FAILURE:
2705 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2706 "have FAILURE change_state return");
2707 /* state change failure */
2708 gst_element_abort_state (element);
2710 case GST_STATE_CHANGE_ASYNC:
2714 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2715 "element will change state ASYNC");
2717 target = GST_STATE_TARGET (element);
2719 if (target > GST_STATE_READY)
2722 /* else we just continue the state change downwards */
2723 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2724 "forcing commit state %s <= %s",
2725 gst_element_state_get_name (target),
2726 gst_element_state_get_name (GST_STATE_READY));
2728 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2731 case GST_STATE_CHANGE_SUCCESS:
2732 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2733 "element changed state SUCCESS");
2734 /* we can commit the state now which will proceeed to
2736 ret = gst_element_continue_state (element, ret);
2738 case GST_STATE_CHANGE_NO_PREROLL:
2739 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2740 "element changed state NO_PREROLL");
2741 /* we can commit the state now which will proceeed to
2743 ret = gst_element_continue_state (element, ret);
2746 goto invalid_return;
2749 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2754 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2762 GST_OBJECT_LOCK (element);
2763 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2764 g_critical ("%s: unknown return value %d from a state change function",
2765 GST_ELEMENT_NAME (element), ret);
2767 /* we are in error now */
2768 ret = GST_STATE_CHANGE_FAILURE;
2769 GST_STATE_RETURN (element) = ret;
2770 GST_OBJECT_UNLOCK (element);
2776 /* gst_iterator_fold functions for pads_activate
2777 * Stop the iterator if activating one pad failed, but only if that pad
2778 * has not been removed from the element. */
2780 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2782 GstPad *pad = g_value_get_object (vpad);
2783 gboolean cont = TRUE;
2785 if (!gst_pad_set_active (pad, *active)) {
2786 if (GST_PAD_PARENT (pad) != NULL) {
2788 g_value_set_boolean (ret, FALSE);
2795 /* returns false on error or early cutout of the fold, true if all
2796 * pads in @iter were (de)activated successfully. */
2798 iterator_activate_fold_with_resync (GstIterator * iter,
2799 GstIteratorFoldFunction func, gpointer user_data)
2801 GstIteratorResult ires;
2804 /* no need to unset this later, it's just a boolean */
2805 g_value_init (&ret, G_TYPE_BOOLEAN);
2806 g_value_set_boolean (&ret, TRUE);
2809 ires = gst_iterator_fold (iter, func, &ret, user_data);
2811 case GST_ITERATOR_RESYNC:
2812 /* need to reset the result again */
2813 g_value_set_boolean (&ret, TRUE);
2814 gst_iterator_resync (iter);
2816 case GST_ITERATOR_DONE:
2817 /* all pads iterated, return collected value */
2820 /* iterator returned _ERROR or premature end with _OK,
2821 * mark an error and exit */
2822 g_value_set_boolean (&ret, FALSE);
2827 /* return collected value */
2828 return g_value_get_boolean (&ret);
2831 /* is called with STATE_LOCK
2833 * Pads are activated from source pads to sinkpads.
2836 gst_element_pads_activate (GstElement * element, gboolean active)
2841 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2842 "%s pads", active ? "activate" : "deactivate");
2844 iter = gst_element_iterate_src_pads (element);
2846 iterator_activate_fold_with_resync (iter,
2847 (GstIteratorFoldFunction) activate_pads, &active);
2848 gst_iterator_free (iter);
2849 if (G_UNLIKELY (!res))
2852 iter = gst_element_iterate_sink_pads (element);
2854 iterator_activate_fold_with_resync (iter,
2855 (GstIteratorFoldFunction) activate_pads, &active);
2856 gst_iterator_free (iter);
2857 if (G_UNLIKELY (!res))
2860 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2861 "pad %sactivation successful", active ? "" : "de");
2868 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2869 "pad %sactivation failed", active ? "" : "de");
2874 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2875 "sink pads_activate failed");
2880 /* is called with STATE_LOCK */
2881 static GstStateChangeReturn
2882 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2884 GstState state, next;
2885 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2887 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2889 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2890 next = GST_STATE_TRANSITION_NEXT (transition);
2892 /* if the element already is in the given state, we just return success */
2893 if (next == GST_STATE_VOID_PENDING || state == next)
2896 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2897 "default handler tries setting state from %s to %s (%04x)",
2898 gst_element_state_get_name (state),
2899 gst_element_state_get_name (next), transition);
2901 switch (transition) {
2902 case GST_STATE_CHANGE_NULL_TO_READY:
2904 case GST_STATE_CHANGE_READY_TO_PAUSED:
2905 if (!gst_element_pads_activate (element, TRUE)) {
2906 result = GST_STATE_CHANGE_FAILURE;
2909 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2911 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2913 case GST_STATE_CHANGE_PAUSED_TO_READY:
2914 case GST_STATE_CHANGE_READY_TO_NULL:{
2917 /* deactivate pads in both cases, since they are activated on
2918 ready->paused but the element might not have made it to paused */
2919 if (!gst_element_pads_activate (element, FALSE)) {
2920 result = GST_STATE_CHANGE_FAILURE;
2923 /* Remove all non-persistent contexts */
2924 GST_OBJECT_LOCK (element);
2925 for (l = element->contexts; l;) {
2926 GstContext *context = l->data;
2928 if (!gst_context_is_persistent (context)) {
2931 gst_context_unref (context);
2933 element->contexts = g_list_delete_link (element->contexts, l);
2939 GST_OBJECT_UNLOCK (element);
2943 /* this will catch real but unhandled state changes;
2944 * can only be caused by:
2945 * - a new state was added
2946 * - somehow the element was asked to jump across an intermediate state
2948 g_warning ("Unhandled state change from %s to %s",
2949 gst_element_state_get_name (state),
2950 gst_element_state_get_name (next));
2957 GST_OBJECT_LOCK (element);
2958 result = GST_STATE_RETURN (element);
2959 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2960 "element is already in the %s state",
2961 gst_element_state_get_name (state));
2962 GST_OBJECT_UNLOCK (element);
2969 * gst_element_get_factory:
2970 * @element: a #GstElement to request the element factory of.
2972 * Retrieves the factory that was used to create this element.
2974 * Returns: (transfer none): the #GstElementFactory used for creating this
2975 * element. no refcounting is needed.
2978 gst_element_get_factory (GstElement * element)
2980 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2982 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2986 gst_element_dispose (GObject * object)
2988 GstElement *element = GST_ELEMENT_CAST (object);
2991 GstElementClass *oclass;
2994 oclass = GST_ELEMENT_GET_CLASS (element);
2996 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
2998 if (GST_STATE (element) != GST_STATE_NULL)
3001 /* start by releasing all request pads, this might also remove some dynamic
3003 walk = element->pads;
3005 GstPad *pad = GST_PAD_CAST (walk->data);
3009 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3010 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3011 == GST_PAD_REQUEST) {
3012 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3013 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3014 oclass->release_pad (element, pad);
3016 /* in case the release_pad function removed the next pad too */
3017 if (walk && g_list_position (element->pads, walk) == -1)
3018 walk = element->pads;
3021 /* remove the remaining pads */
3022 while (element->pads) {
3023 GstPad *pad = GST_PAD_CAST (element->pads->data);
3024 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3025 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3026 if (!gst_element_remove_pad (element, pad)) {
3027 /* only happens when someone unparented our pad.. */
3028 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3033 GST_OBJECT_LOCK (element);
3034 clock_p = &element->clock;
3035 bus_p = &element->bus;
3036 gst_object_replace ((GstObject **) clock_p, NULL);
3037 gst_object_replace ((GstObject **) bus_p, NULL);
3038 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3039 GST_OBJECT_UNLOCK (element);
3041 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3044 G_OBJECT_CLASS (parent_class)->dispose (object);
3053 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3055 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3057 "You need to explicitly set elements to the NULL state before\n"
3058 "dropping the final reference, to allow them to clean up.\n"
3059 "This problem may also be caused by a refcounting bug in the\n"
3060 "application or some element.\n",
3061 GST_OBJECT_NAME (element),
3062 gst_element_state_get_name (GST_STATE (element)),
3063 is_locked ? " (locked)" : "");
3069 gst_element_finalize (GObject * object)
3071 GstElement *element = GST_ELEMENT_CAST (object);
3073 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3075 g_cond_clear (&element->state_cond);
3076 g_rec_mutex_clear (&element->state_lock);
3078 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3081 G_OBJECT_CLASS (parent_class)->finalize (object);
3085 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3089 g_return_if_fail (GST_IS_ELEMENT (element));
3091 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3093 GST_OBJECT_LOCK (element);
3094 bus_p = &GST_ELEMENT_BUS (element);
3095 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3096 GST_OBJECT_UNLOCK (element);
3100 * gst_element_set_bus:
3101 * @element: a #GstElement to set the bus of.
3102 * @bus: (transfer none): the #GstBus to set.
3104 * Sets the bus of the element. Increases the refcount on the bus.
3105 * For internal use only, unless you're testing elements.
3110 gst_element_set_bus (GstElement * element, GstBus * bus)
3112 GstElementClass *oclass;
3114 g_return_if_fail (GST_IS_ELEMENT (element));
3116 oclass = GST_ELEMENT_GET_CLASS (element);
3118 if (oclass->set_bus)
3119 oclass->set_bus (element, bus);
3123 * gst_element_get_bus:
3124 * @element: a #GstElement to get the bus of.
3126 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3127 * bus for the application.
3129 * Returns: (transfer full): the element's #GstBus. unref after usage.
3134 gst_element_get_bus (GstElement * element)
3136 GstBus *result = NULL;
3138 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3140 GST_OBJECT_LOCK (element);
3141 if ((result = GST_ELEMENT_BUS (element)))
3142 gst_object_ref (result);
3143 GST_OBJECT_UNLOCK (element);
3145 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3152 gst_element_set_context_default (GstElement * element, GstContext * context)
3154 const gchar *context_type;
3157 GST_OBJECT_LOCK (element);
3158 context_type = gst_context_get_context_type (context);
3159 for (l = element->contexts; l; l = l->next) {
3160 GstContext *tmp = l->data;
3161 const gchar *tmp_type = gst_context_get_context_type (tmp);
3163 /* Always store newest context but never replace
3164 * a persistent one by a non-persistent one */
3165 if (strcmp (context_type, tmp_type) == 0 &&
3166 (gst_context_is_persistent (context) ||
3167 !gst_context_is_persistent (tmp))) {
3168 gst_context_replace ((GstContext **) & l->data, context);
3172 /* Not found? Add */
3175 g_list_prepend (element->contexts, gst_context_ref (context));
3177 GST_OBJECT_UNLOCK (element);
3181 * gst_element_set_context:
3182 * @element: a #GstElement to set the context of.
3183 * @context: (transfer none): the #GstContext to set.
3185 * Sets the context of the element. Increases the refcount of the context.
3190 gst_element_set_context (GstElement * element, GstContext * context)
3192 GstElementClass *oclass;
3194 g_return_if_fail (GST_IS_ELEMENT (element));
3196 oclass = GST_ELEMENT_GET_CLASS (element);
3198 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3199 "set context %p %" GST_PTR_FORMAT, context,
3200 gst_context_get_structure (context));
3202 if (oclass->set_context)
3203 oclass->set_context (element, context);
3207 * gst_element_get_contexts:
3208 * @element: a #GstElement to set the context of.
3210 * Gets the contexts set on the element.
3214 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3219 gst_element_get_contexts (GstElement * element)
3223 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3225 GST_OBJECT_LOCK (element);
3226 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3227 GST_OBJECT_UNLOCK (element);
3233 _match_context_type (GstContext * c1, const gchar * context_type)
3235 const gchar *c1_type;
3237 c1_type = gst_context_get_context_type (c1);
3239 return g_strcmp0 (c1_type, context_type);
3243 * gst_element_get_context_unlocked:
3244 * @element: a #GstElement to get the context of.
3245 * @context_type: a name of a context to retrieve
3247 * Gets the context with @context_type set on the element or NULL.
3249 * Returns: (transfer full): A #GstContext or NULL
3254 gst_element_get_context_unlocked (GstElement * element,
3255 const gchar * context_type)
3257 GstContext *ret = NULL;
3260 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3263 g_list_find_custom (element->contexts, context_type,
3264 (GCompareFunc) _match_context_type);
3265 if (node && node->data)
3266 ret = gst_context_ref (node->data);
3272 * gst_element_get_context:
3273 * @element: a #GstElement to get the context of.
3274 * @context_type: a name of a context to retrieve
3276 * Gets the context with @context_type set on the element or NULL.
3280 * Returns: (transfer full): A #GstContext or NULL
3285 gst_element_get_context (GstElement * element, const gchar * context_type)
3287 GstContext *ret = NULL;
3289 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3291 GST_OBJECT_LOCK (element);
3292 ret = gst_element_get_context_unlocked (element, context_type);
3293 GST_OBJECT_UNLOCK (element);
3299 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3300 GParamSpec * pspec, gboolean include_value)
3302 GValue val = G_VALUE_INIT;
3305 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3306 "changed, posting message with%s value", pspec->name, obj,
3307 include_value ? "" : "out");
3309 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3310 g_value_init (&val, pspec->value_type);
3311 g_object_get_property (obj, pspec->name, &val);
3316 gst_element_post_message (element,
3317 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3321 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3322 GParamSpec * pspec, gpointer user_data)
3324 gboolean include_value = GPOINTER_TO_INT (user_data);
3326 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3331 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3334 gboolean include_value = GPOINTER_TO_INT (user_data);
3336 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3341 * gst_element_add_property_notify_watch:
3342 * @element: a #GstElement to watch for property changes
3343 * @property_name: (allow-none): name of property to watch for changes, or
3344 * NULL to watch all properties
3345 * @include_value: whether to include the new property value in the message
3347 * Returns: a watch id, which can be used in connection with
3348 * gst_element_remove_property_notify_watch() to remove the watch again.
3353 gst_element_add_property_notify_watch (GstElement * element,
3354 const gchar * property_name, gboolean include_value)
3360 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3362 sep = (property_name != NULL) ? "::" : NULL;
3363 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3364 id = g_signal_connect (element, signal_name,
3365 G_CALLBACK (gst_element_property_notify_cb),
3366 GINT_TO_POINTER (include_value));
3367 g_free (signal_name);
3373 * gst_element_add_property_deep_notify_watch:
3374 * @element: a #GstElement to watch (recursively) for property changes
3375 * @property_name: (allow-none): name of property to watch for changes, or
3376 * NULL to watch all properties
3377 * @include_value: whether to include the new property value in the message
3379 * Returns: a watch id, which can be used in connection with
3380 * gst_element_remove_property_notify_watch() to remove the watch again.
3385 gst_element_add_property_deep_notify_watch (GstElement * element,
3386 const gchar * property_name, gboolean include_value)
3392 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3394 sep = (property_name != NULL) ? "::" : NULL;
3395 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3396 id = g_signal_connect (element, signal_name,
3397 G_CALLBACK (gst_element_property_deep_notify_cb),
3398 GINT_TO_POINTER (include_value));
3399 g_free (signal_name);
3405 * gst_element_remove_property_notify_watch:
3406 * @element: a #GstElement being watched for property changes
3407 * @watch_id: watch id to remove
3412 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3414 g_signal_handler_disconnect (element, watch_id);
3419 GstElement *element;
3420 GstElementCallAsyncFunc func;
3422 GDestroyNotify destroy_notify;
3423 } GstElementCallAsyncData;
3426 gst_element_call_async_func (gpointer data, gpointer user_data)
3428 GstElementCallAsyncData *async_data = data;
3430 async_data->func (async_data->element, async_data->user_data);
3431 if (async_data->destroy_notify)
3432 async_data->destroy_notify (async_data->user_data);
3433 gst_object_unref (async_data->element);
3434 g_free (async_data);
3438 * gst_element_call_async:
3439 * @element: a #GstElement
3440 * @func: Function to call asynchronously from another thread
3441 * @user_data: Data to pass to @func
3442 * @destroy_notify: GDestroyNotify for @user_data
3444 * Calls @func from another thread and passes @user_data to it. This is to be
3445 * used for cases when a state change has to be performed from a streaming
3446 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3449 * Calling those functions directly from the streaming thread will cause
3450 * deadlocks in many situations, as they might involve waiting for the
3451 * streaming thread to shut down from this very streaming thread.
3458 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3459 gpointer user_data, GDestroyNotify destroy_notify)
3461 GstElementCallAsyncData *async_data;
3463 g_return_if_fail (GST_IS_ELEMENT (element));
3465 async_data = g_new0 (GstElementCallAsyncData, 1);
3466 async_data->element = gst_object_ref (element);
3467 async_data->func = func;
3468 async_data->user_data = user_data;
3469 async_data->destroy_notify = destroy_notify;
3471 g_thread_pool_push (gst_element_pool, async_data, NULL);
3475 _priv_gst_element_cleanup (void)
3477 if (gst_element_pool) {
3478 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3479 gst_element_setup_thread_pool ();
3484 gst_element_message_details_new (const char *name, ...)
3486 GstStructure *structure;
3492 va_start (varargs, name);
3493 structure = gst_structure_new_valist ("details", name, varargs);