2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * Elements can have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate.
47 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
49 * Elements can be linked through their pads.
50 * If the link is straightforward, use the gst_element_link()
51 * convenience function to link two elements, or gst_element_link_many()
52 * for more elements in a row.
53 * Use gst_element_link_filtered() to link two elements constrained by
54 * a specified set of #GstCaps.
55 * For finer control, use gst_element_link_pads() and
56 * gst_element_link_pads_filtered() to specify the pads to link on
57 * each element by name.
59 * Each element has a state (see #GstState). You can get and set the state
60 * of an element with gst_element_get_state() and gst_element_set_state().
61 * Setting a state triggers a #GstStateChange. To get a string representation
62 * of a #GstState, use gst_element_state_get_name().
64 * You can get and set a #GstClock on an element using gst_element_get_clock()
65 * and gst_element_set_clock().
66 * Some elements can provide a clock for the pipeline if
67 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the
68 * gst_element_provide_clock() method one can retrieve the clock provided by
70 * Not all elements require a clock to operate correctly. If the
71 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
72 * element with gst_element_set_clock().
74 * Note that clock selection and distribution is normally handled by the
75 * toplevel #GstPipeline so the clock functions are only to be used in very
76 * specific situations.
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstelementmetadata.h"
86 #include "gstenumtypes.h"
93 #include "gsttracerutils.h"
95 #include "gst-i18n-lib.h"
96 #include "glib-compat-private.h"
98 #ifndef GST_DISABLE_GST_DEBUG
99 #include "printf/printf.h"
102 /* Element signals and args */
118 static void gst_element_class_init (GstElementClass * klass);
119 static void gst_element_init (GstElement * element);
120 static void gst_element_base_class_init (gpointer g_class);
122 static void gst_element_constructed (GObject * object);
123 static void gst_element_dispose (GObject * object);
124 static void gst_element_finalize (GObject * object);
126 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
127 GstStateChange transition);
128 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
129 GstState * state, GstState * pending, GstClockTime timeout);
130 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
132 static gboolean gst_element_set_clock_func (GstElement * element,
134 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
135 static gboolean gst_element_post_message_default (GstElement * element,
136 GstMessage * message);
137 static void gst_element_set_context_default (GstElement * element,
138 GstContext * context);
140 static gboolean gst_element_default_send_event (GstElement * element,
142 static gboolean gst_element_default_query (GstElement * element,
145 static GstPadTemplate
146 * gst_element_class_get_request_pad_template (GstElementClass *
147 element_class, const gchar * name);
149 static void gst_element_call_async_func (gpointer data, gpointer user_data);
151 static GstObjectClass *parent_class = NULL;
152 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
154 static GThreadPool *gst_element_pool = NULL;
156 /* this is used in gstelementfactory.c:gst_element_register() */
157 GQuark __gst_elementclass_factory = 0;
160 gst_element_get_type (void)
162 static volatile gsize gst_element_type = 0;
164 if (g_once_init_enter (&gst_element_type)) {
166 static const GTypeInfo element_info = {
167 sizeof (GstElementClass),
168 gst_element_base_class_init,
169 NULL, /* base_class_finalize */
170 (GClassInitFunc) gst_element_class_init,
175 (GInstanceInitFunc) gst_element_init,
179 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
180 &element_info, G_TYPE_FLAG_ABSTRACT);
182 __gst_elementclass_factory =
183 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
184 g_once_init_leave (&gst_element_type, _type);
186 return gst_element_type;
190 gst_element_setup_thread_pool (void)
194 GST_DEBUG ("creating element thread pool");
196 g_thread_pool_new ((GFunc) gst_element_call_async_func, NULL, -1, FALSE,
199 g_critical ("could not alloc threadpool %s", err->message);
200 g_clear_error (&err);
205 gst_element_class_init (GstElementClass * klass)
207 GObjectClass *gobject_class;
209 gobject_class = (GObjectClass *) klass;
211 parent_class = g_type_class_peek_parent (klass);
214 * GstElement::pad-added:
215 * @gstelement: the object which received the signal
216 * @new_pad: the pad that has been added
218 * a new #GstPad has been added to the element. Note that this signal will
219 * usually be emitted from the context of the streaming thread. Also keep in
220 * mind that if you add new elements to the pipeline in the signal handler
221 * you will need to set them to the desired target state with
222 * gst_element_set_state() or gst_element_sync_state_with_parent().
224 gst_element_signals[PAD_ADDED] =
225 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
226 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
227 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
229 * GstElement::pad-removed:
230 * @gstelement: the object which received the signal
231 * @old_pad: the pad that has been removed
233 * a #GstPad has been removed from the element
235 gst_element_signals[PAD_REMOVED] =
236 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
237 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
238 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
240 * GstElement::no-more-pads:
241 * @gstelement: the object which received the signal
243 * This signals that the element will not generate more dynamic pads.
244 * Note that this signal will usually be emitted from the context of
245 * the streaming thread.
247 gst_element_signals[NO_MORE_PADS] =
248 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
249 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
250 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
252 gobject_class->dispose = gst_element_dispose;
253 gobject_class->finalize = gst_element_finalize;
254 gobject_class->constructed = gst_element_constructed;
256 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
257 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
258 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
259 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
260 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
261 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
262 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
263 klass->numpadtemplates = 0;
264 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
265 klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_default);
267 klass->elementfactory = NULL;
269 gst_element_setup_thread_pool ();
273 gst_element_base_class_init (gpointer g_class)
275 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
276 GList *node, *padtemplates;
278 /* Copy the element details here so elements can inherit the
279 * details from their base class and classes only need to set
280 * the details in class_init instead of base_init */
281 element_class->metadata =
282 element_class->metadata ? gst_structure_copy (element_class->metadata) :
283 gst_structure_new_empty ("metadata");
285 /* Copy the pad templates so elements inherit them
286 * from their base class but elements can add pad templates in class_init
287 * instead of base_init.
289 padtemplates = g_list_copy (element_class->padtemplates);
290 for (node = padtemplates; node != NULL; node = node->next) {
291 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
292 gst_object_ref (tmpl);
294 element_class->padtemplates = padtemplates;
296 /* set the factory, see gst_element_register() */
297 element_class->elementfactory =
298 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
299 __gst_elementclass_factory);
300 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
301 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
305 gst_element_init (GstElement * element)
307 GST_STATE (element) = GST_STATE_NULL;
308 GST_STATE_TARGET (element) = GST_STATE_NULL;
309 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
310 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
311 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
313 g_rec_mutex_init (&element->state_lock);
314 g_cond_init (&element->state_cond);
318 gst_element_constructed (GObject * object)
320 GST_TRACER_ELEMENT_NEW (GST_ELEMENT_CAST (object));
321 G_OBJECT_CLASS (parent_class)->constructed (object);
325 * gst_element_release_request_pad:
326 * @element: a #GstElement to release the request pad of.
327 * @pad: the #GstPad to release.
329 * Makes the element free the previously requested pad as obtained
330 * with gst_element_request_pad().
332 * This does not unref the pad. If the pad was created by using
333 * gst_element_request_pad(), gst_element_release_request_pad() needs to be
334 * followed by gst_object_unref() to free the @pad.
339 gst_element_release_request_pad (GstElement * element, GstPad * pad)
341 GstElementClass *oclass;
343 g_return_if_fail (GST_IS_ELEMENT (element));
344 g_return_if_fail (GST_IS_PAD (pad));
345 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
346 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
349 oclass = GST_ELEMENT_GET_CLASS (element);
351 /* if the element implements a custom release function we call that, else we
352 * simply remove the pad from the element */
353 if (oclass->release_pad)
354 oclass->release_pad (element, pad);
356 gst_element_remove_pad (element, pad);
360 * gst_element_provide_clock:
361 * @element: a #GstElement to query
363 * Get the clock provided by the given element.
364 * <note>An element is only required to provide a clock in the PAUSED
365 * state. Some elements can provide a clock in other states.</note>
367 * Returns: (transfer full) (nullable): the GstClock provided by the
368 * element or %NULL if no clock could be provided. Unref after usage.
373 gst_element_provide_clock (GstElement * element)
375 GstClock *result = NULL;
376 GstElementClass *oclass;
378 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
380 oclass = GST_ELEMENT_GET_CLASS (element);
382 if (oclass->provide_clock)
383 result = oclass->provide_clock (element);
389 gst_element_set_clock_func (GstElement * element, GstClock * clock)
393 GST_OBJECT_LOCK (element);
394 clock_p = &element->clock;
395 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
396 GST_OBJECT_UNLOCK (element);
402 * gst_element_set_clock:
403 * @element: a #GstElement to set the clock for.
404 * @clock: the #GstClock to set for the element.
406 * Sets the clock for the element. This function increases the
407 * refcount on the clock. Any previously set clock on the object
410 * Returns: %TRUE if the element accepted the clock. An element can refuse a
411 * clock when it, for example, is not able to slave its internal clock to the
412 * @clock or when it requires a specific clock to operate.
417 gst_element_set_clock (GstElement * element, GstClock * clock)
419 GstElementClass *oclass;
420 gboolean res = FALSE;
422 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
423 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
425 oclass = GST_ELEMENT_GET_CLASS (element);
427 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
429 if (oclass->set_clock)
430 res = oclass->set_clock (element, clock);
436 * gst_element_get_clock:
437 * @element: a #GstElement to get the clock of.
439 * Gets the currently configured clock of the element. This is the clock as was
440 * last set with gst_element_set_clock().
442 * Elements in a pipeline will only have their clock set when the
443 * pipeline is in the PLAYING state.
445 * Returns: (transfer full): the #GstClock of the element. unref after usage.
450 gst_element_get_clock (GstElement * element)
454 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
456 GST_OBJECT_LOCK (element);
457 if ((result = element->clock))
458 gst_object_ref (result);
459 GST_OBJECT_UNLOCK (element);
465 * gst_element_set_base_time:
466 * @element: a #GstElement.
467 * @time: the base time to set.
469 * Set the base time of an element. See gst_element_get_base_time().
474 gst_element_set_base_time (GstElement * element, GstClockTime time)
478 g_return_if_fail (GST_IS_ELEMENT (element));
480 GST_OBJECT_LOCK (element);
481 old = element->base_time;
482 element->base_time = time;
483 GST_OBJECT_UNLOCK (element);
485 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
486 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
487 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
491 * gst_element_get_base_time:
492 * @element: a #GstElement.
494 * Returns the base time of the element. The base time is the
495 * absolute time of the clock when this element was last put to
496 * PLAYING. Subtracting the base time from the clock time gives
497 * the running time of the element.
499 * Returns: the base time of the element.
504 gst_element_get_base_time (GstElement * element)
508 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
510 GST_OBJECT_LOCK (element);
511 result = element->base_time;
512 GST_OBJECT_UNLOCK (element);
518 * gst_element_set_start_time:
519 * @element: a #GstElement.
520 * @time: the base time to set.
522 * Set the start time of an element. The start time of the element is the
523 * running time of the element when it last went to the PAUSED state. In READY
524 * or after a flushing seek, it is set to 0.
526 * Toplevel elements like #GstPipeline will manage the start_time and
527 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
528 * on such a toplevel element will disable the distribution of the base_time to
529 * the children and can be useful if the application manages the base_time
530 * itself, for example if you want to synchronize capture from multiple
531 * pipelines, and you can also ensure that the pipelines have the same clock.
536 gst_element_set_start_time (GstElement * element, GstClockTime time)
540 g_return_if_fail (GST_IS_ELEMENT (element));
542 GST_OBJECT_LOCK (element);
543 old = GST_ELEMENT_START_TIME (element);
544 GST_ELEMENT_START_TIME (element) = time;
545 GST_OBJECT_UNLOCK (element);
547 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
548 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
549 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
553 * gst_element_get_start_time:
554 * @element: a #GstElement.
556 * Returns the start time of the element. The start time is the
557 * running time of the clock when this element was last put to PAUSED.
559 * Usually the start_time is managed by a toplevel element such as
564 * Returns: the start time of the element.
567 gst_element_get_start_time (GstElement * element)
571 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
573 GST_OBJECT_LOCK (element);
574 result = GST_ELEMENT_START_TIME (element);
575 GST_OBJECT_UNLOCK (element);
582 * gst_element_set_index:
583 * @element: a #GstElement.
584 * @index: (transfer none): a #GstIndex.
586 * Set @index on the element. The refcount of the index
587 * will be increased, any previously set index is unreffed.
592 gst_element_set_index (GstElement * element, GstIndex * index)
594 GstElementClass *oclass;
596 g_return_if_fail (GST_IS_ELEMENT (element));
597 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
599 oclass = GST_ELEMENT_GET_CLASS (element);
601 if (oclass->set_index)
602 oclass->set_index (element, index);
606 * gst_element_get_index:
607 * @element: a #GstElement.
609 * Gets the index from the element.
611 * Returns: (transfer full) (nullable): a #GstIndex or %NULL when no
612 * index was set on the element. unref after usage.
617 gst_element_get_index (GstElement * element)
619 GstElementClass *oclass;
620 GstIndex *result = NULL;
622 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
624 oclass = GST_ELEMENT_GET_CLASS (element);
626 if (oclass->get_index)
627 result = oclass->get_index (element);
634 * gst_element_add_pad:
635 * @element: a #GstElement to add the pad to.
636 * @pad: (transfer full): the #GstPad to add to the element.
638 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
639 * see gst_object_set_parent() for refcounting information.
641 * Pads are not automatically activated so elements should perform the needed
642 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
643 * state. See gst_pad_set_active() for more information about activating pads.
645 * The pad and the element should be unlocked when calling this function.
647 * This function will emit the #GstElement::pad-added signal on the element.
649 * Returns: %TRUE if the pad could be added. This function can fail when
650 * a pad with the same name already existed or the pad already had another
656 gst_element_add_pad (GstElement * element, GstPad * pad)
661 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
662 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
664 /* locking pad to look at the name */
665 GST_OBJECT_LOCK (pad);
666 pad_name = g_strdup (GST_PAD_NAME (pad));
667 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
668 GST_STR_NULL (pad_name));
669 active = GST_PAD_IS_ACTIVE (pad);
670 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
671 GST_OBJECT_UNLOCK (pad);
673 /* then check to see if there's already a pad by that name here */
674 GST_OBJECT_LOCK (element);
675 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
678 /* try to set the pad's parent */
679 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
680 GST_OBJECT_CAST (element))))
683 /* check for active pads */
684 if (!active && (GST_STATE (element) > GST_STATE_READY ||
685 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
686 g_warning ("adding inactive pad '%s' to running element '%s', you need to "
687 "use gst_pad_set_active(pad,TRUE) before adding it.",
688 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
689 gst_pad_set_active (pad, TRUE);
694 /* add it to the list */
695 switch (gst_pad_get_direction (pad)) {
697 element->srcpads = g_list_append (element->srcpads, pad);
698 element->numsrcpads++;
701 element->sinkpads = g_list_append (element->sinkpads, pad);
702 element->numsinkpads++;
707 element->pads = g_list_append (element->pads, pad);
709 element->pads_cookie++;
710 GST_OBJECT_UNLOCK (element);
712 /* emit the PAD_ADDED signal */
713 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
714 GST_TRACER_ELEMENT_ADD_PAD (element, pad);
720 g_critical ("Padname %s is not unique in element %s, not adding",
721 pad_name, GST_ELEMENT_NAME (element));
722 GST_OBJECT_UNLOCK (element);
729 ("Pad %s already has parent when trying to add to element %s",
730 pad_name, GST_ELEMENT_NAME (element));
731 GST_OBJECT_UNLOCK (element);
737 GST_OBJECT_LOCK (pad);
739 ("Trying to add pad %s to element %s, but it has no direction",
740 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
741 GST_OBJECT_UNLOCK (pad);
742 GST_OBJECT_UNLOCK (element);
748 * gst_element_remove_pad:
749 * @element: a #GstElement to remove pad from.
750 * @pad: (transfer full): the #GstPad to remove from the element.
752 * Removes @pad from @element. @pad will be destroyed if it has not been
753 * referenced elsewhere using gst_object_unparent().
755 * This function is used by plugin developers and should not be used
756 * by applications. Pads that were dynamically requested from elements
757 * with gst_element_request_pad() should be released with the
758 * gst_element_release_request_pad() function instead.
760 * Pads are not automatically deactivated so elements should perform the needed
761 * steps to deactivate the pad in case this pad is removed in the PAUSED or
762 * PLAYING state. See gst_pad_set_active() for more information about
765 * The pad and the element should be unlocked when calling this function.
767 * This function will emit the #GstElement::pad-removed signal on the element.
769 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
770 * pad does not belong to the provided element.
775 gst_element_remove_pad (GstElement * element, GstPad * pad)
779 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
780 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
782 /* locking pad to look at the name and parent */
783 GST_OBJECT_LOCK (pad);
784 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
785 GST_STR_NULL (GST_PAD_NAME (pad)));
787 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
789 GST_OBJECT_UNLOCK (pad);
792 if ((peer = gst_pad_get_peer (pad))) {
793 /* window for MT unsafeness, someone else could unlink here
794 * and then we call unlink with wrong pads. The unlink
795 * function would catch this and safely return failed. */
796 if (GST_PAD_IS_SRC (pad))
797 gst_pad_unlink (pad, peer);
799 gst_pad_unlink (peer, pad);
801 gst_object_unref (peer);
804 GST_OBJECT_LOCK (element);
805 /* remove it from the list */
806 switch (gst_pad_get_direction (pad)) {
808 element->srcpads = g_list_remove (element->srcpads, pad);
809 element->numsrcpads--;
812 element->sinkpads = g_list_remove (element->sinkpads, pad);
813 element->numsinkpads--;
816 g_critical ("Removing pad without direction???");
819 element->pads = g_list_remove (element->pads, pad);
821 element->pads_cookie++;
822 GST_OBJECT_UNLOCK (element);
824 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
825 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
826 GST_TRACER_ELEMENT_REMOVE_PAD (element, pad);
827 gst_object_unparent (GST_OBJECT_CAST (pad));
834 /* locking order is element > pad */
835 GST_OBJECT_UNLOCK (pad);
837 GST_OBJECT_LOCK (element);
838 GST_OBJECT_LOCK (pad);
839 g_critical ("Padname %s:%s does not belong to element %s when removing",
840 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
841 GST_OBJECT_UNLOCK (pad);
842 GST_OBJECT_UNLOCK (element);
848 * gst_element_no_more_pads:
849 * @element: a #GstElement
851 * Use this function to signal that the element does not expect any more pads
852 * to show up in the current pipeline. This function should be called whenever
853 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
854 * pad templates use this in combination with autopluggers to figure out that
855 * the element is done initializing its pads.
857 * This function emits the #GstElement::no-more-pads signal.
862 gst_element_no_more_pads (GstElement * element)
864 g_return_if_fail (GST_IS_ELEMENT (element));
866 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
870 pad_compare_name (GstPad * pad1, const gchar * name)
874 GST_OBJECT_LOCK (pad1);
875 result = strcmp (GST_PAD_NAME (pad1), name);
876 GST_OBJECT_UNLOCK (pad1);
882 * gst_element_get_static_pad:
883 * @element: a #GstElement to find a static pad of.
884 * @name: the name of the static #GstPad to retrieve.
886 * Retrieves a pad from @element by name. This version only retrieves
887 * already-existing (i.e. 'static') pads.
889 * Returns: (transfer full) (nullable): the requested #GstPad if
890 * found, otherwise %NULL. unref after usage.
895 gst_element_get_static_pad (GstElement * element, const gchar * name)
898 GstPad *result = NULL;
900 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
901 g_return_val_if_fail (name != NULL, NULL);
903 GST_OBJECT_LOCK (element);
905 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
907 result = GST_PAD_CAST (find->data);
908 gst_object_ref (result);
911 if (result == NULL) {
912 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
913 name, GST_ELEMENT_NAME (element));
915 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
916 GST_ELEMENT_NAME (element), name);
918 GST_OBJECT_UNLOCK (element);
924 gst_element_is_valid_request_template_name (const gchar * templ_name,
928 const gchar *templ_name_ptr, *name_ptr;
929 gboolean next_specifier;
930 guint templ_postfix_len = 0, name_postfix_len = 0;
932 g_return_val_if_fail (templ_name != NULL, FALSE);
933 g_return_val_if_fail (name != NULL, FALSE);
935 /* Is this the template name? */
936 if (strcmp (templ_name, name) == 0)
939 /* otherwise check all the specifiers */
941 /* Because of sanity checks in gst_pad_template_new(), we know that %s
942 * and %d and %u, occurring at the template_name */
943 templ_name_ptr = strchr (templ_name, '%');
945 /* check characters ahead of the specifier */
946 if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
947 || strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
951 /* %s is not allowed for multiple specifiers, just a single specifier can be
952 * accepted in gst_pad_template_new() and can not be mixed with other
953 * specifier '%u' and '%d' */
954 if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
958 name_ptr = name + (templ_name_ptr - templ_name);
960 /* search next specifier, each of specifier should be separated by '_' */
961 templ_name = strchr (templ_name_ptr, '_');
962 name = strchr (name_ptr, '_');
964 /* don't match the number of specifiers */
965 if ((templ_name && !name) || (!templ_name && name))
968 if (templ_name && name)
969 next_specifier = TRUE;
971 next_specifier = FALSE;
973 /* check characters followed by the specifier */
974 if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
975 if (next_specifier) {
976 templ_postfix_len = templ_name - (templ_name_ptr + 2);
977 name_postfix_len = name - name_ptr;
979 templ_postfix_len = strlen (templ_name_ptr + 2);
980 name_postfix_len = strlen (name_ptr);
983 if (strncmp (templ_name_ptr + 2,
984 name_ptr + name_postfix_len - templ_postfix_len,
985 templ_postfix_len) != 0) {
990 /* verify the specifier */
991 if (*(name_ptr) == '%') {
994 len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
996 if (strncmp (name_ptr, templ_name_ptr, len) != 0)
1000 const gchar *specifier;
1001 gchar *target = NULL;
1003 /* extract specifier when it has postfix characters */
1004 if (name_postfix_len > templ_postfix_len) {
1005 target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
1007 specifier = target ? target : name_ptr;
1009 if (*(templ_name_ptr + 1) == 'd') {
1013 tmp = g_ascii_strtoll (specifier, &endptr, 10);
1014 if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
1017 } else if (*(templ_name_ptr + 1) == 'u') {
1021 tmp = g_ascii_strtoull (specifier, &endptr, 10);
1022 if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
1029 /* otherwise we increment these from NULL to 1 */
1030 if (next_specifier) {
1034 } while (next_specifier);
1040 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
1041 const gchar * name, const GstCaps * caps)
1043 GstPad *newpad = NULL;
1044 GstElementClass *oclass;
1046 oclass = GST_ELEMENT_GET_CLASS (element);
1048 #ifndef G_DISABLE_CHECKS
1049 /* Some sanity checking here */
1053 g_return_val_if_fail (gst_element_is_valid_request_template_name
1054 (templ->name_template, name), NULL);
1056 pad = gst_element_get_static_pad (element, name);
1058 gst_object_unref (pad);
1059 /* FIXME 2.0: Change this to g_return_val_if_fail() */
1060 g_critical ("Element %s already has a pad named %s, the behaviour of "
1061 " gst_element_get_request_pad() for existing pads is undefined!",
1062 GST_ELEMENT_NAME (element), name);
1067 if (oclass->request_new_pad)
1068 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1071 gst_object_ref (newpad);
1077 * gst_element_get_request_pad:
1078 * @element: a #GstElement to find a request pad of.
1079 * @name: the name of the request #GstPad to retrieve.
1081 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1082 * retrieves request pads. The pad should be released with
1083 * gst_element_release_request_pad().
1085 * This method is slower than manually getting the pad template and calling
1086 * gst_element_request_pad() if the pads should have a specific name (e.g.
1087 * @name is "src_1" instead of "src_\%u").
1089 * Returns: (transfer full) (nullable): requested #GstPad if found,
1090 * otherwise %NULL. Release after usage.
1093 gst_element_get_request_pad (GstElement * element, const gchar * name)
1095 GstPadTemplate *templ = NULL;
1097 const gchar *req_name = NULL;
1098 gboolean templ_found = FALSE;
1100 GstElementClass *class;
1102 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1103 g_return_val_if_fail (name != NULL, NULL);
1105 class = GST_ELEMENT_GET_CLASS (element);
1107 templ = gst_element_class_get_request_pad_template (class, name);
1109 req_name = strstr (name, "%") ? NULL : name;
1112 /* there is no % in the name, try to find a matching template */
1113 list = class->padtemplates;
1114 while (!templ_found && list) {
1115 templ = (GstPadTemplate *) list->data;
1116 if (templ->presence == GST_PAD_REQUEST) {
1117 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1118 templ->name_template);
1119 if (gst_element_is_valid_request_template_name (templ->name_template,
1133 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1139 * gst_element_request_pad: (virtual request_new_pad)
1140 * @element: a #GstElement to find a request pad of.
1141 * @templ: a #GstPadTemplate of which we want a pad of.
1142 * @name: (transfer none) (allow-none): the name of the request #GstPad
1143 * to retrieve. Can be %NULL.
1144 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1145 * request. Can be %NULL.
1147 * Retrieves a request pad from the element according to the provided template.
1148 * Pad templates can be looked up using
1149 * gst_element_factory_get_static_pad_templates().
1151 * The pad should be released with gst_element_release_request_pad().
1153 * Returns: (transfer full) (nullable): requested #GstPad if found,
1154 * otherwise %NULL. Release after usage.
1157 gst_element_request_pad (GstElement * element,
1158 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1160 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1161 g_return_val_if_fail (templ != NULL, NULL);
1162 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1164 return _gst_element_request_pad (element, templ, name, caps);
1167 static GstIterator *
1168 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1170 GstIterator *result;
1172 GST_OBJECT_LOCK (element);
1173 result = gst_iterator_new_list (GST_TYPE_PAD,
1174 GST_OBJECT_GET_LOCK (element),
1175 &element->pads_cookie, padlist, (GObject *) element, NULL);
1176 GST_OBJECT_UNLOCK (element);
1182 * gst_element_iterate_pads:
1183 * @element: a #GstElement to iterate pads of.
1185 * Retrieves an iterator of @element's pads. The iterator should
1186 * be freed after usage. Also more specialized iterators exists such as
1187 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1189 * The order of pads returned by the iterator will be the order in which
1190 * the pads were added to the element.
1192 * Returns: (transfer full): the #GstIterator of #GstPad.
1197 gst_element_iterate_pads (GstElement * element)
1199 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1201 return gst_element_iterate_pad_list (element, &element->pads);
1205 * gst_element_iterate_src_pads:
1206 * @element: a #GstElement.
1208 * Retrieves an iterator of @element's source pads.
1210 * The order of pads returned by the iterator will be the order in which
1211 * the pads were added to the element.
1213 * Returns: (transfer full): the #GstIterator of #GstPad.
1218 gst_element_iterate_src_pads (GstElement * element)
1220 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1222 return gst_element_iterate_pad_list (element, &element->srcpads);
1226 * gst_element_iterate_sink_pads:
1227 * @element: a #GstElement.
1229 * Retrieves an iterator of @element's sink pads.
1231 * The order of pads returned by the iterator will be the order in which
1232 * the pads were added to the element.
1234 * Returns: (transfer full): the #GstIterator of #GstPad.
1239 gst_element_iterate_sink_pads (GstElement * element)
1241 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1243 return gst_element_iterate_pad_list (element, &element->sinkpads);
1247 * gst_element_class_add_pad_template:
1248 * @klass: the #GstElementClass to add the pad template to.
1249 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1251 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1252 * functions of classes. If a pad template with the same name as an already
1253 * existing one is added the old one is replaced by the new one.
1257 gst_element_class_add_pad_template (GstElementClass * klass,
1258 GstPadTemplate * templ)
1260 GList *template_list = klass->padtemplates;
1262 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1263 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1265 /* If we already have a pad template with the same name replace the
1267 while (template_list) {
1268 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1270 /* Found pad with the same name, replace and return */
1271 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1272 gst_object_unref (padtempl);
1273 template_list->data = templ;
1276 template_list = g_list_next (template_list);
1279 /* Take ownership of the floating ref */
1280 gst_object_ref_sink (templ);
1282 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1283 klass->numpadtemplates++;
1287 * gst_element_class_add_static_pad_template:
1288 * @klass: the #GstElementClass to add the pad template to.
1289 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1291 * Adds a pad template to an element class based on the static pad template
1292 * @templ. This is mainly used in the _class_init functions of element
1293 * implementations. If a pad template with the same name already exists,
1294 * the old one is replaced by the new one.
1299 gst_element_class_add_static_pad_template (GstElementClass * klass,
1300 GstStaticPadTemplate * static_templ)
1302 gst_element_class_add_pad_template (klass,
1303 gst_static_pad_template_get (static_templ));
1307 * gst_element_class_add_metadata:
1308 * @klass: class to set metadata for
1309 * @key: the key to set
1310 * @value: the value to set
1312 * Set @key with @value as metadata in @klass.
1315 gst_element_class_add_metadata (GstElementClass * klass,
1316 const gchar * key, const gchar * value)
1318 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1319 g_return_if_fail (key != NULL);
1320 g_return_if_fail (value != NULL);
1322 gst_structure_set ((GstStructure *) klass->metadata,
1323 key, G_TYPE_STRING, value, NULL);
1327 * gst_element_class_add_static_metadata:
1328 * @klass: class to set metadata for
1329 * @key: the key to set
1330 * @value: the value to set
1332 * Set @key with @value as metadata in @klass.
1334 * Same as gst_element_class_add_metadata(), but @value must be a static string
1335 * or an inlined string, as it will not be copied. (GStreamer plugins will
1336 * be made resident once loaded, so this function can be used even from
1337 * dynamically loaded plugins.)
1340 gst_element_class_add_static_metadata (GstElementClass * klass,
1341 const gchar * key, const gchar * value)
1343 GValue val = G_VALUE_INIT;
1345 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1346 g_return_if_fail (key != NULL);
1347 g_return_if_fail (value != NULL);
1349 g_value_init (&val, G_TYPE_STRING);
1350 g_value_set_static_string (&val, value);
1351 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1355 * gst_element_class_set_metadata:
1356 * @klass: class to set metadata for
1357 * @longname: The long English name of the element. E.g. "File Sink"
1358 * @classification: String describing the type of element, as an unordered list
1359 * separated with slashes ('/'). See draft-klass.txt of the design docs
1360 * for more details and common types. E.g: "Sink/File"
1361 * @description: Sentence describing the purpose of the element.
1362 * E.g: "Write stream to a file"
1363 * @author: Name and contact details of the author(s). Use \n to separate
1364 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1366 * Sets the detailed information for a #GstElementClass.
1367 * <note>This function is for use in _class_init functions only.</note>
1370 gst_element_class_set_metadata (GstElementClass * klass,
1371 const gchar * longname, const gchar * classification,
1372 const gchar * description, const gchar * author)
1374 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1375 g_return_if_fail (longname != NULL && *longname != '\0');
1376 g_return_if_fail (classification != NULL && *classification != '\0');
1377 g_return_if_fail (description != NULL && *description != '\0');
1378 g_return_if_fail (author != NULL && *author != '\0');
1380 gst_structure_id_set ((GstStructure *) klass->metadata,
1381 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1382 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1383 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1384 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1388 * gst_element_class_set_static_metadata:
1389 * @klass: class to set metadata for
1390 * @longname: The long English name of the element. E.g. "File Sink"
1391 * @classification: String describing the type of element, as an unordered list
1392 * separated with slashes ('/'). See draft-klass.txt of the design docs
1393 * for more details and common types. E.g: "Sink/File"
1394 * @description: Sentence describing the purpose of the element.
1395 * E.g: "Write stream to a file"
1396 * @author: Name and contact details of the author(s). Use \n to separate
1397 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1399 * Sets the detailed information for a #GstElementClass.
1400 * <note>This function is for use in _class_init functions only.</note>
1402 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1403 * @description, and @author must be static strings or inlined strings, as
1404 * they will not be copied. (GStreamer plugins will be made resident once
1405 * loaded, so this function can be used even from dynamically loaded plugins.)
1408 gst_element_class_set_static_metadata (GstElementClass * klass,
1409 const gchar * longname, const gchar * classification,
1410 const gchar * description, const gchar * author)
1412 GstStructure *s = (GstStructure *) klass->metadata;
1413 GValue val = G_VALUE_INIT;
1415 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1416 g_return_if_fail (longname != NULL && *longname != '\0');
1417 g_return_if_fail (classification != NULL && *classification != '\0');
1418 g_return_if_fail (description != NULL && *description != '\0');
1419 g_return_if_fail (author != NULL && *author != '\0');
1421 g_value_init (&val, G_TYPE_STRING);
1423 g_value_set_static_string (&val, longname);
1424 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1426 g_value_set_static_string (&val, classification);
1427 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1429 g_value_set_static_string (&val, description);
1430 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1433 g_value_set_static_string (&val, author);
1434 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1438 * gst_element_class_get_metadata:
1439 * @klass: class to get metadata for
1440 * @key: the key to get
1442 * Get metadata with @key in @klass.
1444 * Returns: the metadata for @key.
1447 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1449 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1450 g_return_val_if_fail (key != NULL, NULL);
1452 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1456 * gst_element_class_get_pad_template_list:
1457 * @element_class: a #GstElementClass to get pad templates of.
1459 * Retrieves a list of the pad templates associated with @element_class. The
1460 * list must not be modified by the calling code.
1461 * <note>If you use this function in the #GInstanceInitFunc of an object class
1462 * that has subclasses, make sure to pass the g_class parameter of the
1463 * #GInstanceInitFunc here.</note>
1465 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1469 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1471 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1473 return element_class->padtemplates;
1477 * gst_element_class_get_pad_template:
1478 * @element_class: a #GstElementClass to get the pad template of.
1479 * @name: the name of the #GstPadTemplate to get.
1481 * Retrieves a padtemplate from @element_class with the given name.
1482 * <note>If you use this function in the #GInstanceInitFunc of an object class
1483 * that has subclasses, make sure to pass the g_class parameter of the
1484 * #GInstanceInitFunc here.</note>
1486 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1487 * given name, or %NULL if none was found. No unreferencing is
1491 gst_element_class_get_pad_template (GstElementClass *
1492 element_class, const gchar * name)
1496 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1497 g_return_val_if_fail (name != NULL, NULL);
1499 padlist = element_class->padtemplates;
1502 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1504 if (strcmp (padtempl->name_template, name) == 0)
1507 padlist = g_list_next (padlist);
1513 static GstPadTemplate *
1514 gst_element_class_get_request_pad_template (GstElementClass *
1515 element_class, const gchar * name)
1517 GstPadTemplate *tmpl;
1519 tmpl = gst_element_class_get_pad_template (element_class, name);
1520 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1526 /* get a random pad on element of the given direction.
1527 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1530 gst_element_get_random_pad (GstElement * element,
1531 gboolean need_linked, GstPadDirection dir)
1533 GstPad *result = NULL;
1536 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1540 GST_OBJECT_LOCK (element);
1541 pads = element->srcpads;
1544 GST_OBJECT_LOCK (element);
1545 pads = element->sinkpads;
1548 goto wrong_direction;
1550 for (; pads; pads = g_list_next (pads)) {
1551 GstPad *pad = GST_PAD_CAST (pads->data);
1553 GST_OBJECT_LOCK (pad);
1554 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1555 GST_DEBUG_PAD_NAME (pad));
1557 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1558 /* if we require a linked pad, and it is not linked, continue the
1560 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1561 GST_DEBUG_PAD_NAME (pad));
1562 GST_OBJECT_UNLOCK (pad);
1565 /* found a pad, stop search */
1566 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1567 GST_DEBUG_PAD_NAME (pad));
1568 GST_OBJECT_UNLOCK (pad);
1574 gst_object_ref (result);
1576 GST_OBJECT_UNLOCK (element);
1580 /* ERROR handling */
1583 g_warning ("unknown pad direction %d", dir);
1589 gst_element_default_send_event (GstElement * element, GstEvent * event)
1591 gboolean result = FALSE;
1594 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1595 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1596 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1599 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1600 "pushing %s event to random %s pad %s:%s",
1601 GST_EVENT_TYPE_NAME (event),
1602 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1603 GST_DEBUG_PAD_NAME (pad));
1605 result = gst_pad_send_event (pad, event);
1606 gst_object_unref (pad);
1608 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1609 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1610 gst_event_unref (event);
1616 * gst_element_send_event:
1617 * @element: a #GstElement to send the event to.
1618 * @event: (transfer full): the #GstEvent to send to the element.
1620 * Sends an event to an element. If the element doesn't implement an
1621 * event handler, the event will be pushed on a random linked sink pad for
1622 * downstream events or a random linked source pad for upstream events.
1624 * This function takes ownership of the provided event so you should
1625 * gst_event_ref() it if you want to reuse the event after this call.
1629 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1630 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1633 gst_element_send_event (GstElement * element, GstEvent * event)
1635 GstElementClass *oclass;
1636 gboolean result = FALSE;
1638 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1639 g_return_val_if_fail (event != NULL, FALSE);
1641 oclass = GST_ELEMENT_GET_CLASS (element);
1643 GST_STATE_LOCK (element);
1644 if (oclass->send_event) {
1645 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1646 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1647 result = oclass->send_event (element, event);
1649 gst_event_unref (event);
1651 GST_STATE_UNLOCK (element);
1658 * @element: a #GstElement to send the event to.
1659 * @rate: The new playback rate
1660 * @format: The format of the seek values
1661 * @flags: The optional seek flags.
1662 * @start_type: The type and flags for the new start position
1663 * @start: The value of the new start position
1664 * @stop_type: The type and flags for the new stop position
1665 * @stop: The value of the new stop position
1667 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1668 * the parameters. The seek event is sent to the element using
1669 * gst_element_send_event().
1673 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1674 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1677 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1678 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1679 GstSeekType stop_type, gint64 stop)
1684 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1687 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1689 result = gst_element_send_event (element, event);
1695 gst_element_default_query (GstElement * element, GstQuery * query)
1697 gboolean result = FALSE;
1700 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1702 result = gst_pad_query (pad, query);
1704 gst_object_unref (pad);
1706 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1708 GstPad *peer = gst_pad_get_peer (pad);
1711 result = gst_pad_query (peer, query);
1713 gst_object_unref (peer);
1715 gst_object_unref (pad);
1722 * gst_element_query:
1723 * @element: a #GstElement to perform the query on.
1724 * @query: (transfer none): the #GstQuery.
1726 * Performs a query on the given element.
1728 * For elements that don't implement a query handler, this function
1729 * forwards the query to a random srcpad or to the peer of a
1730 * random linked sinkpad of this element.
1732 * Please note that some queries might need a running pipeline to work.
1734 * Returns: %TRUE if the query could be performed.
1739 gst_element_query (GstElement * element, GstQuery * query)
1741 GstElementClass *klass;
1742 gboolean res = FALSE;
1744 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1745 g_return_val_if_fail (query != NULL, FALSE);
1747 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1749 klass = GST_ELEMENT_GET_CLASS (element);
1751 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1752 GST_ELEMENT_NAME (element));
1753 res = klass->query (element, query);
1756 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1761 gst_element_post_message_default (GstElement * element, GstMessage * message)
1764 gboolean result = FALSE;
1766 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1767 g_return_val_if_fail (message != NULL, FALSE);
1769 GST_OBJECT_LOCK (element);
1772 if (G_UNLIKELY (bus == NULL))
1775 gst_object_ref (bus);
1776 GST_OBJECT_UNLOCK (element);
1778 /* we release the element lock when posting the message so that any
1779 * (synchronous) message handlers can operate on the element */
1780 result = gst_bus_post (bus, message);
1781 gst_object_unref (bus);
1788 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1789 "not posting message %p: no bus", message);
1790 GST_OBJECT_UNLOCK (element);
1791 gst_message_unref (message);
1797 * gst_element_post_message:
1798 * @element: a #GstElement posting the message
1799 * @message: (transfer full): a #GstMessage to post
1801 * Post a message on the element's #GstBus. This function takes ownership of the
1802 * message; if you want to access the message after this call, you should add an
1803 * additional reference before calling.
1805 * Returns: %TRUE if the message was successfully posted. The function returns
1806 * %FALSE if the element did not have a bus.
1811 gst_element_post_message (GstElement * element, GstMessage * message)
1813 GstElementClass *klass;
1814 gboolean res = FALSE;
1816 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1817 g_return_val_if_fail (message != NULL, FALSE);
1819 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1821 klass = GST_ELEMENT_GET_CLASS (element);
1822 if (klass->post_message)
1823 res = klass->post_message (element, message);
1825 gst_message_unref (message);
1827 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1832 * _gst_element_error_printf:
1833 * @format: (allow-none): the printf-like format to use, or %NULL
1835 * This function is only used internally by the gst_element_error() macro.
1837 * Returns: (transfer full) (nullable): a newly allocated string, or
1838 * %NULL if the format was %NULL or ""
1843 _gst_element_error_printf (const gchar * format, ...)
1854 va_start (args, format);
1856 len = __gst_vasprintf (&buffer, format, args);
1867 * gst_element_message_full_with_details:
1868 * @element: a #GstElement to send message from
1869 * @type: the #GstMessageType
1870 * @domain: the GStreamer GError domain this message belongs to
1871 * @code: the GError code belonging to the domain
1872 * @text: (allow-none) (transfer full): an allocated text string to be used
1873 * as a replacement for the default message connected to code,
1875 * @debug: (allow-none) (transfer full): an allocated debug message to be
1876 * used as a replacement for the default debugging information,
1878 * @file: the source code file where the error was generated
1879 * @function: the source code function where the error was generated
1880 * @line: the source code line where the error was generated
1881 * @structure:(transfer full): optional details structure
1883 * Post an error, warning or info message on the bus from inside an element.
1885 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1886 * #GST_MESSAGE_INFO.
1890 void gst_element_message_full_with_details
1891 (GstElement * element, GstMessageType type,
1892 GQuark domain, gint code, gchar * text,
1893 gchar * debug, const gchar * file, const gchar * function, gint line,
1894 GstStructure * structure)
1896 GError *gerror = NULL;
1900 gboolean has_debug = TRUE;
1901 GstMessage *message = NULL;
1904 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1905 g_return_if_fail (GST_IS_ELEMENT (element));
1906 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1907 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1909 /* check if we send the given text or the default error text */
1910 if ((text == NULL) || (text[0] == 0)) {
1911 /* text could have come from g_strdup_printf (""); */
1913 sent_text = gst_error_get_message (domain, code);
1917 /* construct a sent_debug with extra information from source */
1918 if ((debug == NULL) || (debug[0] == 0)) {
1919 /* debug could have come from g_strdup_printf (""); */
1923 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1925 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1926 file, line, function, name, debug);
1928 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1929 file, line, function, name);
1933 /* create gerror and post message */
1934 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1936 gerror = g_error_new_literal (domain, code, sent_text);
1939 case GST_MESSAGE_ERROR:
1941 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1942 sent_debug, structure);
1944 case GST_MESSAGE_WARNING:
1946 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1947 gerror, sent_debug, structure);
1949 case GST_MESSAGE_INFO:
1951 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1952 sent_debug, structure);
1955 g_assert_not_reached ();
1959 gst_element_post_message (element, message);
1961 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1962 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1965 g_error_free (gerror);
1966 g_free (sent_debug);
1971 * gst_element_message_full:
1972 * @element: a #GstElement to send message from
1973 * @type: the #GstMessageType
1974 * @domain: the GStreamer GError domain this message belongs to
1975 * @code: the GError code belonging to the domain
1976 * @text: (allow-none) (transfer full): an allocated text string to be used
1977 * as a replacement for the default message connected to code,
1979 * @debug: (allow-none) (transfer full): an allocated debug message to be
1980 * used as a replacement for the default debugging information,
1982 * @file: the source code file where the error was generated
1983 * @function: the source code function where the error was generated
1984 * @line: the source code line where the error was generated
1986 * Post an error, warning or info message on the bus from inside an element.
1988 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1989 * #GST_MESSAGE_INFO.
1993 void gst_element_message_full
1994 (GstElement * element, GstMessageType type,
1995 GQuark domain, gint code, gchar * text,
1996 gchar * debug, const gchar * file, const gchar * function, gint line)
1998 gst_element_message_full_with_details (element, type, domain, code, text,
1999 debug, file, function, line, NULL);
2003 * gst_element_is_locked_state:
2004 * @element: a #GstElement.
2006 * Checks if the state of an element is locked.
2007 * If the state of an element is locked, state changes of the parent don't
2008 * affect the element.
2009 * This way you can leave currently unused elements inside bins. Just lock their
2010 * state before changing the state from #GST_STATE_NULL.
2014 * Returns: %TRUE, if the element's state is locked.
2017 gst_element_is_locked_state (GstElement * element)
2021 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2023 GST_OBJECT_LOCK (element);
2024 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2025 GST_OBJECT_UNLOCK (element);
2031 * gst_element_set_locked_state:
2032 * @element: a #GstElement
2033 * @locked_state: %TRUE to lock the element's state
2035 * Locks the state of an element, so state changes of the parent don't affect
2036 * this element anymore.
2040 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2041 * or the elements state-locking needed no change.
2044 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2048 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2050 GST_OBJECT_LOCK (element);
2051 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2053 if (G_UNLIKELY (old == locked_state))
2057 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2058 GST_ELEMENT_NAME (element));
2059 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2061 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2062 GST_ELEMENT_NAME (element));
2063 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2065 GST_OBJECT_UNLOCK (element);
2071 GST_CAT_DEBUG (GST_CAT_STATES,
2072 "elements %s was already in locked state %d",
2073 GST_ELEMENT_NAME (element), old);
2074 GST_OBJECT_UNLOCK (element);
2081 * gst_element_sync_state_with_parent:
2082 * @element: a #GstElement.
2084 * Tries to change the state of the element to the same as its parent.
2085 * If this function returns %FALSE, the state of element is undefined.
2087 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2092 gst_element_sync_state_with_parent (GstElement * element)
2096 GstStateChangeReturn ret;
2098 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2100 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2101 GstState parent_current, parent_pending;
2103 GST_OBJECT_LOCK (parent);
2104 parent_current = GST_STATE (parent);
2105 parent_pending = GST_STATE_PENDING (parent);
2106 GST_OBJECT_UNLOCK (parent);
2108 /* set to pending if there is one, else we set it to the current state of
2110 if (parent_pending != GST_STATE_VOID_PENDING)
2111 target = parent_pending;
2113 target = parent_current;
2115 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2116 "syncing state (%s) to parent %s %s (%s, %s)",
2117 gst_element_state_get_name (GST_STATE (element)),
2118 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2119 gst_element_state_get_name (parent_current),
2120 gst_element_state_get_name (parent_pending));
2122 ret = gst_element_set_state (element, target);
2123 if (ret == GST_STATE_CHANGE_FAILURE)
2126 gst_object_unref (parent);
2130 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2137 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2138 "syncing state failed (%s)",
2139 gst_element_state_change_return_get_name (ret));
2140 gst_object_unref (parent);
2146 static GstStateChangeReturn
2147 gst_element_get_state_func (GstElement * element,
2148 GstState * state, GstState * pending, GstClockTime timeout)
2150 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2151 GstState old_pending;
2153 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2154 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2156 GST_OBJECT_LOCK (element);
2157 ret = GST_STATE_RETURN (element);
2158 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2159 gst_element_state_change_return_get_name (ret));
2161 /* we got an error, report immediately */
2162 if (ret == GST_STATE_CHANGE_FAILURE)
2165 /* we got no_preroll, report immediately */
2166 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2169 /* no need to wait async if we are not async */
2170 if (ret != GST_STATE_CHANGE_ASYNC)
2173 old_pending = GST_STATE_PENDING (element);
2174 if (old_pending != GST_STATE_VOID_PENDING) {
2178 /* get cookie to detect state changes during waiting */
2179 cookie = element->state_cookie;
2181 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2182 "waiting for element to commit state");
2184 /* we have a pending state change, wait for it to complete */
2185 if (timeout != GST_CLOCK_TIME_NONE) {
2187 /* make timeout absolute */
2188 end_time = g_get_monotonic_time () + (timeout / 1000);
2189 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2191 GST_STATE_WAIT (element);
2196 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2197 /* timeout triggered */
2198 ret = GST_STATE_CHANGE_ASYNC;
2200 if (cookie != element->state_cookie)
2203 /* could be success or failure */
2204 if (old_pending == GST_STATE (element)) {
2205 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2206 ret = GST_STATE_CHANGE_SUCCESS;
2208 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2209 ret = GST_STATE_CHANGE_FAILURE;
2212 /* if nothing is pending anymore we can return SUCCESS */
2213 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2214 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2215 ret = GST_STATE_CHANGE_SUCCESS;
2221 *state = GST_STATE (element);
2223 *pending = GST_STATE_PENDING (element);
2225 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2226 "state current: %s, pending: %s, result: %s",
2227 gst_element_state_get_name (GST_STATE (element)),
2228 gst_element_state_get_name (GST_STATE_PENDING (element)),
2229 gst_element_state_change_return_get_name (ret));
2230 GST_OBJECT_UNLOCK (element);
2237 *state = GST_STATE_VOID_PENDING;
2239 *pending = GST_STATE_VOID_PENDING;
2241 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2243 GST_OBJECT_UNLOCK (element);
2245 return GST_STATE_CHANGE_FAILURE;
2250 * gst_element_get_state:
2251 * @element: a #GstElement to get the state of.
2252 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2254 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2255 * state. Can be %NULL.
2256 * @timeout: a #GstClockTime to specify the timeout for an async
2257 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2259 * Gets the state of the element.
2261 * For elements that performed an ASYNC state change, as reported by
2262 * gst_element_set_state(), this function will block up to the
2263 * specified timeout value for the state change to complete.
2264 * If the element completes the state change or goes into
2265 * an error, this function returns immediately with a return value of
2266 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2268 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2269 * returns the current and pending state immediately.
2271 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2272 * successfully changed its state but is not able to provide data yet.
2273 * This mostly happens for live sources that only produce data in
2274 * %GST_STATE_PLAYING. While the state change return is equivalent to
2275 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2276 * some sink elements might not be able to complete their state change because
2277 * an element is not producing data to complete the preroll. When setting the
2278 * element to playing, the preroll will complete and playback will start.
2280 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2281 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2282 * element is still performing a state change or
2283 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2287 GstStateChangeReturn
2288 gst_element_get_state (GstElement * element,
2289 GstState * state, GstState * pending, GstClockTime timeout)
2291 GstElementClass *oclass;
2292 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2294 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2296 oclass = GST_ELEMENT_GET_CLASS (element);
2298 if (oclass->get_state)
2299 result = (oclass->get_state) (element, state, pending, timeout);
2305 * gst_element_abort_state:
2306 * @element: a #GstElement to abort the state of.
2308 * Abort the state change of the element. This function is used
2309 * by elements that do asynchronous state changes and find out
2310 * something is wrong.
2312 * This function should be called with the STATE_LOCK held.
2317 gst_element_abort_state (GstElement * element)
2321 #ifndef GST_DISABLE_GST_DEBUG
2325 g_return_if_fail (GST_IS_ELEMENT (element));
2327 GST_OBJECT_LOCK (element);
2328 pending = GST_STATE_PENDING (element);
2330 if (pending == GST_STATE_VOID_PENDING ||
2331 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2332 goto nothing_aborted;
2334 #ifndef GST_DISABLE_GST_DEBUG
2335 old_state = GST_STATE (element);
2337 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2338 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2339 gst_element_state_get_name (pending));
2343 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2345 GST_STATE_BROADCAST (element);
2346 GST_OBJECT_UNLOCK (element);
2352 GST_OBJECT_UNLOCK (element);
2357 /* Not static because GstBin has manual state handling too */
2359 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2360 GstState newstate, GstState pending)
2362 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2363 GstMessage *message;
2365 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2366 "notifying about state-changed %s to %s (%s pending)",
2367 gst_element_state_get_name (oldstate),
2368 gst_element_state_get_name (newstate),
2369 gst_element_state_get_name (pending));
2371 if (klass->state_changed)
2372 klass->state_changed (element, oldstate, newstate, pending);
2374 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2375 oldstate, newstate, pending);
2376 gst_element_post_message (element, message);
2380 * gst_element_continue_state:
2381 * @element: a #GstElement to continue the state change of.
2382 * @ret: The previous state return value
2384 * Commit the state change of the element and proceed to the next
2385 * pending state if any. This function is used
2386 * by elements that do asynchronous state changes.
2387 * The core will normally call this method automatically when an
2388 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2390 * If after calling this method the element still has not reached
2391 * the pending state, the next state change is performed.
2393 * This method is used internally and should normally not be called by plugins
2396 * Returns: The result of the commit state change.
2400 GstStateChangeReturn
2401 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2403 GstStateChangeReturn old_ret;
2404 GstState old_state, old_next;
2405 GstState current, next, pending;
2406 GstStateChange transition;
2408 GST_OBJECT_LOCK (element);
2409 old_ret = GST_STATE_RETURN (element);
2410 GST_STATE_RETURN (element) = ret;
2411 pending = GST_STATE_PENDING (element);
2413 /* check if there is something to commit */
2414 if (pending == GST_STATE_VOID_PENDING)
2415 goto nothing_pending;
2417 old_state = GST_STATE (element);
2418 /* this is the state we should go to next */
2419 old_next = GST_STATE_NEXT (element);
2420 /* update current state */
2421 current = GST_STATE (element) = old_next;
2423 /* see if we reached the final state */
2424 if (pending == current)
2427 next = GST_STATE_GET_NEXT (current, pending);
2428 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2430 GST_STATE_NEXT (element) = next;
2432 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2433 GST_OBJECT_UNLOCK (element);
2435 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2436 "committing state from %s to %s, pending %s, next %s",
2437 gst_element_state_get_name (old_state),
2438 gst_element_state_get_name (old_next),
2439 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2441 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2443 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2444 "continue state change %s to %s, final %s",
2445 gst_element_state_get_name (current),
2446 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2448 ret = gst_element_change_state (element, transition);
2454 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2455 GST_OBJECT_UNLOCK (element);
2460 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2461 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2463 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2464 "completed state change to %s", gst_element_state_get_name (pending));
2465 GST_OBJECT_UNLOCK (element);
2467 /* don't post silly messages with the same state. This can happen
2468 * when an element state is changed to what it already was. For bins
2469 * this can be the result of a lost state, which we check with the
2470 * previous return value.
2471 * We do signal the cond though as a _get_state() might be blocking
2473 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2474 _priv_gst_element_state_changed (element, old_state, old_next,
2475 GST_STATE_VOID_PENDING);
2477 GST_STATE_BROADCAST (element);
2484 * gst_element_lost_state:
2485 * @element: a #GstElement the state is lost of
2487 * Brings the element to the lost state. The current state of the
2488 * element is copied to the pending state so that any call to
2489 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2491 * An ASYNC_START message is posted. If the element was PLAYING, it will
2492 * go to PAUSED. The element will be restored to its PLAYING state by
2493 * the parent pipeline when it prerolls again.
2495 * This is mostly used for elements that lost their preroll buffer
2496 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2497 * they will go to their pending state again when a new preroll buffer is
2498 * queued. This function can only be called when the element is currently
2499 * not in error or an async state change.
2501 * This function is used internally and should normally not be called from
2502 * plugins or applications.
2505 gst_element_lost_state (GstElement * element)
2507 GstState old_state, new_state;
2508 GstMessage *message;
2510 g_return_if_fail (GST_IS_ELEMENT (element));
2512 GST_OBJECT_LOCK (element);
2513 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2516 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2517 goto only_async_start;
2519 old_state = GST_STATE (element);
2521 /* when we were PLAYING, the new state is PAUSED. We will also not
2522 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2523 * when we preroll. */
2524 if (old_state > GST_STATE_PAUSED)
2525 new_state = GST_STATE_PAUSED;
2527 new_state = old_state;
2529 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2530 "lost state of %s to %s", gst_element_state_get_name (old_state),
2531 gst_element_state_get_name (new_state));
2533 GST_STATE (element) = new_state;
2534 GST_STATE_NEXT (element) = new_state;
2535 GST_STATE_PENDING (element) = new_state;
2536 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2537 GST_OBJECT_UNLOCK (element);
2539 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2541 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2542 gst_element_post_message (element, message);
2548 GST_OBJECT_UNLOCK (element);
2553 GST_OBJECT_UNLOCK (element);
2555 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2556 gst_element_post_message (element, message);
2562 * gst_element_set_state:
2563 * @element: a #GstElement to change state of.
2564 * @state: the element's new #GstState.
2566 * Sets the state of the element. This function will try to set the
2567 * requested state by going through all the intermediary states and calling
2568 * the class's state change function for each.
2570 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2571 * element will perform the remainder of the state change asynchronously in
2573 * An application can use gst_element_get_state() to wait for the completion
2574 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2575 * %GST_MESSAGE_STATE_CHANGED on the bus.
2577 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2578 * #GST_STATE_CHANGE_ASYNC.
2580 * Returns: Result of the state change using #GstStateChangeReturn.
2584 GstStateChangeReturn
2585 gst_element_set_state (GstElement * element, GstState state)
2587 GstElementClass *oclass;
2588 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2590 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2592 oclass = GST_ELEMENT_GET_CLASS (element);
2594 if (oclass->set_state)
2595 result = (oclass->set_state) (element, state);
2601 * default set state function, calculates the next state based
2602 * on current state and calls the change_state function
2604 static GstStateChangeReturn
2605 gst_element_set_state_func (GstElement * element, GstState state)
2607 GstState current, next, old_pending;
2608 GstStateChangeReturn ret;
2609 GstStateChange transition;
2610 GstStateChangeReturn old_ret;
2612 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2614 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2615 gst_element_state_get_name (state));
2617 /* state lock is taken to protect the set_state() and get_state()
2618 * procedures, it does not lock any variables. */
2619 GST_STATE_LOCK (element);
2621 /* now calculate how to get to the new state */
2622 GST_OBJECT_LOCK (element);
2623 old_ret = GST_STATE_RETURN (element);
2624 /* previous state change returned an error, remove all pending
2625 * and next states */
2626 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2627 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2628 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2629 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2632 current = GST_STATE (element);
2633 next = GST_STATE_NEXT (element);
2634 old_pending = GST_STATE_PENDING (element);
2636 /* this is the (new) state we should go to. TARGET is the last state we set on
2638 if (state != GST_STATE_TARGET (element)) {
2639 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2640 "setting target state to %s", gst_element_state_get_name (state));
2641 GST_STATE_TARGET (element) = state;
2642 /* increment state cookie so that we can track each state change. We only do
2643 * this if this is actually a new state change. */
2644 element->state_cookie++;
2646 GST_STATE_PENDING (element) = state;
2648 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2649 "current %s, old_pending %s, next %s, old return %s",
2650 gst_element_state_get_name (current),
2651 gst_element_state_get_name (old_pending),
2652 gst_element_state_get_name (next),
2653 gst_element_state_change_return_get_name (old_ret));
2655 /* if the element was busy doing a state change, we just update the
2656 * target state, it'll get to it async then. */
2657 if (old_pending != GST_STATE_VOID_PENDING) {
2658 /* upwards state change will happen ASYNC */
2659 if (old_pending <= state)
2661 /* element is going to this state already */
2662 else if (next == state)
2664 /* element was performing an ASYNC upward state change and
2665 * we request to go downward again. Start from the next pending
2667 else if (next > state
2668 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2672 next = GST_STATE_GET_NEXT (current, state);
2673 /* now we store the next state */
2674 GST_STATE_NEXT (element) = next;
2675 /* mark busy, we need to check that there is actually a state change
2676 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2677 * the default element change_state function has no way to know what the
2678 * old value was... could consider this a FIXME...*/
2679 if (current != next)
2680 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2682 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2684 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2685 "%s: setting state from %s to %s",
2686 (next != state ? "intermediate" : "final"),
2687 gst_element_state_get_name (current), gst_element_state_get_name (next));
2689 /* now signal any waiters, they will error since the cookie was incremented */
2690 GST_STATE_BROADCAST (element);
2692 GST_OBJECT_UNLOCK (element);
2694 ret = gst_element_change_state (element, transition);
2696 GST_STATE_UNLOCK (element);
2698 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2699 gst_element_state_change_return_get_name (ret));
2705 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2706 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2707 "element was busy with async state change");
2708 GST_OBJECT_UNLOCK (element);
2710 GST_STATE_UNLOCK (element);
2712 return GST_STATE_CHANGE_ASYNC;
2717 * gst_element_change_state:
2718 * @element: a #GstElement
2719 * @transition: the requested transition
2721 * Perform @transition on @element.
2723 * This function must be called with STATE_LOCK held and is mainly used
2726 * Returns: the #GstStateChangeReturn of the state transition.
2728 GstStateChangeReturn
2729 gst_element_change_state (GstElement * element, GstStateChange transition)
2731 GstElementClass *oclass;
2732 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2734 oclass = GST_ELEMENT_GET_CLASS (element);
2736 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2738 /* call the state change function so it can set the state */
2739 if (oclass->change_state)
2740 ret = (oclass->change_state) (element, transition);
2742 ret = GST_STATE_CHANGE_FAILURE;
2744 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2747 case GST_STATE_CHANGE_FAILURE:
2748 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2749 "have FAILURE change_state return");
2750 /* state change failure */
2751 gst_element_abort_state (element);
2753 case GST_STATE_CHANGE_ASYNC:
2757 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2758 "element will change state ASYNC");
2760 target = GST_STATE_TARGET (element);
2762 if (target > GST_STATE_READY)
2765 /* else we just continue the state change downwards */
2766 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2767 "forcing commit state %s <= %s",
2768 gst_element_state_get_name (target),
2769 gst_element_state_get_name (GST_STATE_READY));
2771 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2774 case GST_STATE_CHANGE_SUCCESS:
2775 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2776 "element changed state SUCCESS");
2777 /* we can commit the state now which will proceeed to
2779 ret = gst_element_continue_state (element, ret);
2781 case GST_STATE_CHANGE_NO_PREROLL:
2782 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2783 "element changed state NO_PREROLL");
2784 /* we can commit the state now which will proceeed to
2786 ret = gst_element_continue_state (element, ret);
2789 goto invalid_return;
2792 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2797 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2805 GST_OBJECT_LOCK (element);
2806 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2807 g_critical ("%s: unknown return value %d from a state change function",
2808 GST_ELEMENT_NAME (element), ret);
2810 /* we are in error now */
2811 ret = GST_STATE_CHANGE_FAILURE;
2812 GST_STATE_RETURN (element) = ret;
2813 GST_OBJECT_UNLOCK (element);
2819 /* gst_iterator_fold functions for pads_activate
2820 * Stop the iterator if activating one pad failed, but only if that pad
2821 * has not been removed from the element. */
2823 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2825 GstPad *pad = g_value_get_object (vpad);
2826 gboolean cont = TRUE;
2828 if (!gst_pad_set_active (pad, *active)) {
2829 if (GST_PAD_PARENT (pad) != NULL) {
2831 g_value_set_boolean (ret, FALSE);
2838 /* returns false on error or early cutout of the fold, true if all
2839 * pads in @iter were (de)activated successfully. */
2841 iterator_activate_fold_with_resync (GstIterator * iter,
2842 GstIteratorFoldFunction func, gpointer user_data)
2844 GstIteratorResult ires;
2847 /* no need to unset this later, it's just a boolean */
2848 g_value_init (&ret, G_TYPE_BOOLEAN);
2849 g_value_set_boolean (&ret, TRUE);
2852 ires = gst_iterator_fold (iter, func, &ret, user_data);
2854 case GST_ITERATOR_RESYNC:
2855 /* need to reset the result again */
2856 g_value_set_boolean (&ret, TRUE);
2857 gst_iterator_resync (iter);
2859 case GST_ITERATOR_DONE:
2860 /* all pads iterated, return collected value */
2863 /* iterator returned _ERROR or premature end with _OK,
2864 * mark an error and exit */
2865 g_value_set_boolean (&ret, FALSE);
2870 /* return collected value */
2871 return g_value_get_boolean (&ret);
2874 /* is called with STATE_LOCK
2876 * Pads are activated from source pads to sinkpads.
2879 gst_element_pads_activate (GstElement * element, gboolean active)
2884 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2885 "%s pads", active ? "activate" : "deactivate");
2887 iter = gst_element_iterate_src_pads (element);
2889 iterator_activate_fold_with_resync (iter,
2890 (GstIteratorFoldFunction) activate_pads, &active);
2891 gst_iterator_free (iter);
2892 if (G_UNLIKELY (!res))
2895 iter = gst_element_iterate_sink_pads (element);
2897 iterator_activate_fold_with_resync (iter,
2898 (GstIteratorFoldFunction) activate_pads, &active);
2899 gst_iterator_free (iter);
2900 if (G_UNLIKELY (!res))
2903 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2904 "pad %sactivation successful", active ? "" : "de");
2911 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2912 "pad %sactivation failed", active ? "" : "de");
2917 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2918 "sink pads_activate failed");
2923 /* is called with STATE_LOCK */
2924 static GstStateChangeReturn
2925 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2927 GstState state, next;
2928 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2930 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2932 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2933 next = GST_STATE_TRANSITION_NEXT (transition);
2935 /* if the element already is in the given state, we just return success */
2936 if (next == GST_STATE_VOID_PENDING || state == next)
2939 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2940 "default handler tries setting state from %s to %s (%04x)",
2941 gst_element_state_get_name (state),
2942 gst_element_state_get_name (next), transition);
2944 switch (transition) {
2945 case GST_STATE_CHANGE_NULL_TO_READY:
2947 case GST_STATE_CHANGE_READY_TO_PAUSED:
2948 if (!gst_element_pads_activate (element, TRUE)) {
2949 result = GST_STATE_CHANGE_FAILURE;
2952 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2954 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2956 case GST_STATE_CHANGE_PAUSED_TO_READY:
2957 case GST_STATE_CHANGE_READY_TO_NULL:{
2960 /* deactivate pads in both cases, since they are activated on
2961 ready->paused but the element might not have made it to paused */
2962 if (!gst_element_pads_activate (element, FALSE)) {
2963 result = GST_STATE_CHANGE_FAILURE;
2966 /* Remove all non-persistent contexts */
2967 GST_OBJECT_LOCK (element);
2968 for (l = element->contexts; l;) {
2969 GstContext *context = l->data;
2971 if (!gst_context_is_persistent (context)) {
2974 gst_context_unref (context);
2976 element->contexts = g_list_delete_link (element->contexts, l);
2982 GST_OBJECT_UNLOCK (element);
2986 /* this will catch real but unhandled state changes;
2987 * can only be caused by:
2988 * - a new state was added
2989 * - somehow the element was asked to jump across an intermediate state
2991 g_warning ("Unhandled state change from %s to %s",
2992 gst_element_state_get_name (state),
2993 gst_element_state_get_name (next));
3000 GST_OBJECT_LOCK (element);
3001 result = GST_STATE_RETURN (element);
3002 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3003 "element is already in the %s state",
3004 gst_element_state_get_name (state));
3005 GST_OBJECT_UNLOCK (element);
3012 * gst_element_get_factory:
3013 * @element: a #GstElement to request the element factory of.
3015 * Retrieves the factory that was used to create this element.
3017 * Returns: (transfer none): the #GstElementFactory used for creating this
3018 * element. no refcounting is needed.
3021 gst_element_get_factory (GstElement * element)
3023 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3025 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3029 gst_element_dispose (GObject * object)
3031 GstElement *element = GST_ELEMENT_CAST (object);
3034 GstElementClass *oclass;
3037 oclass = GST_ELEMENT_GET_CLASS (element);
3039 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3041 if (GST_STATE (element) != GST_STATE_NULL)
3044 /* start by releasing all request pads, this might also remove some dynamic
3046 walk = element->pads;
3048 GstPad *pad = GST_PAD_CAST (walk->data);
3052 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3053 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3054 == GST_PAD_REQUEST) {
3055 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3056 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3057 oclass->release_pad (element, pad);
3059 /* in case the release_pad function removed the next pad too */
3060 if (walk && g_list_position (element->pads, walk) == -1)
3061 walk = element->pads;
3064 /* remove the remaining pads */
3065 while (element->pads) {
3066 GstPad *pad = GST_PAD_CAST (element->pads->data);
3067 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3068 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3069 if (!gst_element_remove_pad (element, pad)) {
3070 /* only happens when someone unparented our pad.. */
3071 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3076 GST_OBJECT_LOCK (element);
3077 clock_p = &element->clock;
3078 bus_p = &element->bus;
3079 gst_object_replace ((GstObject **) clock_p, NULL);
3080 gst_object_replace ((GstObject **) bus_p, NULL);
3081 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3082 GST_OBJECT_UNLOCK (element);
3084 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3087 G_OBJECT_CLASS (parent_class)->dispose (object);
3096 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3098 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3100 "You need to explicitly set elements to the NULL state before\n"
3101 "dropping the final reference, to allow them to clean up.\n"
3102 "This problem may also be caused by a refcounting bug in the\n"
3103 "application or some element.\n",
3104 GST_OBJECT_NAME (element),
3105 gst_element_state_get_name (GST_STATE (element)),
3106 is_locked ? " (locked)" : "");
3112 gst_element_finalize (GObject * object)
3114 GstElement *element = GST_ELEMENT_CAST (object);
3116 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3118 g_cond_clear (&element->state_cond);
3119 g_rec_mutex_clear (&element->state_lock);
3121 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3124 G_OBJECT_CLASS (parent_class)->finalize (object);
3128 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3132 g_return_if_fail (GST_IS_ELEMENT (element));
3134 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3136 GST_OBJECT_LOCK (element);
3137 bus_p = &GST_ELEMENT_BUS (element);
3138 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3139 GST_OBJECT_UNLOCK (element);
3143 * gst_element_set_bus:
3144 * @element: a #GstElement to set the bus of.
3145 * @bus: (transfer none): the #GstBus to set.
3147 * Sets the bus of the element. Increases the refcount on the bus.
3148 * For internal use only, unless you're testing elements.
3153 gst_element_set_bus (GstElement * element, GstBus * bus)
3155 GstElementClass *oclass;
3157 g_return_if_fail (GST_IS_ELEMENT (element));
3159 oclass = GST_ELEMENT_GET_CLASS (element);
3161 if (oclass->set_bus)
3162 oclass->set_bus (element, bus);
3166 * gst_element_get_bus:
3167 * @element: a #GstElement to get the bus of.
3169 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3170 * bus for the application.
3172 * Returns: (transfer full): the element's #GstBus. unref after usage.
3177 gst_element_get_bus (GstElement * element)
3179 GstBus *result = NULL;
3181 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3183 GST_OBJECT_LOCK (element);
3184 if ((result = GST_ELEMENT_BUS (element)))
3185 gst_object_ref (result);
3186 GST_OBJECT_UNLOCK (element);
3188 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3195 gst_element_set_context_default (GstElement * element, GstContext * context)
3197 const gchar *context_type;
3200 g_return_if_fail (GST_IS_CONTEXT (context));
3201 context_type = gst_context_get_context_type (context);
3202 g_return_if_fail (context_type != NULL);
3204 GST_OBJECT_LOCK (element);
3205 for (l = element->contexts; l; l = l->next) {
3206 GstContext *tmp = l->data;
3207 const gchar *tmp_type = gst_context_get_context_type (tmp);
3209 /* Always store newest context but never replace
3210 * a persistent one by a non-persistent one */
3211 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3212 (gst_context_is_persistent (context) ||
3213 !gst_context_is_persistent (tmp))) {
3214 gst_context_replace ((GstContext **) & l->data, context);
3218 /* Not found? Add */
3221 g_list_prepend (element->contexts, gst_context_ref (context));
3223 GST_OBJECT_UNLOCK (element);
3227 * gst_element_set_context:
3228 * @element: a #GstElement to set the context of.
3229 * @context: (transfer none): the #GstContext to set.
3231 * Sets the context of the element. Increases the refcount of the context.
3236 gst_element_set_context (GstElement * element, GstContext * context)
3238 GstElementClass *oclass;
3240 g_return_if_fail (GST_IS_ELEMENT (element));
3241 g_return_if_fail (GST_IS_CONTEXT (context));
3243 oclass = GST_ELEMENT_GET_CLASS (element);
3245 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3246 "set context %p %" GST_PTR_FORMAT, context,
3247 gst_context_get_structure (context));
3249 if (oclass->set_context)
3250 oclass->set_context (element, context);
3254 * gst_element_get_contexts:
3255 * @element: a #GstElement to set the context of.
3257 * Gets the contexts set on the element.
3261 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3266 gst_element_get_contexts (GstElement * element)
3270 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3272 GST_OBJECT_LOCK (element);
3273 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3274 GST_OBJECT_UNLOCK (element);
3280 _match_context_type (GstContext * c1, const gchar * context_type)
3282 const gchar *c1_type;
3284 c1_type = gst_context_get_context_type (c1);
3286 return g_strcmp0 (c1_type, context_type);
3290 * gst_element_get_context_unlocked:
3291 * @element: a #GstElement to get the context of.
3292 * @context_type: a name of a context to retrieve
3294 * Gets the context with @context_type set on the element or NULL.
3296 * Returns: (transfer full): A #GstContext or NULL
3301 gst_element_get_context_unlocked (GstElement * element,
3302 const gchar * context_type)
3304 GstContext *ret = NULL;
3307 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3310 g_list_find_custom (element->contexts, context_type,
3311 (GCompareFunc) _match_context_type);
3312 if (node && node->data)
3313 ret = gst_context_ref (node->data);
3319 * gst_element_get_context:
3320 * @element: a #GstElement to get the context of.
3321 * @context_type: a name of a context to retrieve
3323 * Gets the context with @context_type set on the element or NULL.
3327 * Returns: (transfer full): A #GstContext or NULL
3332 gst_element_get_context (GstElement * element, const gchar * context_type)
3334 GstContext *ret = NULL;
3336 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3338 GST_OBJECT_LOCK (element);
3339 ret = gst_element_get_context_unlocked (element, context_type);
3340 GST_OBJECT_UNLOCK (element);
3346 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3347 GParamSpec * pspec, gboolean include_value)
3349 GValue val = G_VALUE_INIT;
3352 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3353 "changed, posting message with%s value", pspec->name, obj,
3354 include_value ? "" : "out");
3356 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3357 g_value_init (&val, pspec->value_type);
3358 g_object_get_property (obj, pspec->name, &val);
3363 gst_element_post_message (element,
3364 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3368 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3369 GParamSpec * pspec, gpointer user_data)
3371 gboolean include_value = GPOINTER_TO_INT (user_data);
3373 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3378 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3381 gboolean include_value = GPOINTER_TO_INT (user_data);
3383 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3388 * gst_element_add_property_notify_watch:
3389 * @element: a #GstElement to watch for property changes
3390 * @property_name: (allow-none): name of property to watch for changes, or
3391 * NULL to watch all properties
3392 * @include_value: whether to include the new property value in the message
3394 * Returns: a watch id, which can be used in connection with
3395 * gst_element_remove_property_notify_watch() to remove the watch again.
3400 gst_element_add_property_notify_watch (GstElement * element,
3401 const gchar * property_name, gboolean include_value)
3407 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3409 sep = (property_name != NULL) ? "::" : NULL;
3410 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3411 id = g_signal_connect (element, signal_name,
3412 G_CALLBACK (gst_element_property_notify_cb),
3413 GINT_TO_POINTER (include_value));
3414 g_free (signal_name);
3420 * gst_element_add_property_deep_notify_watch:
3421 * @element: a #GstElement to watch (recursively) for property changes
3422 * @property_name: (allow-none): name of property to watch for changes, or
3423 * NULL to watch all properties
3424 * @include_value: whether to include the new property value in the message
3426 * Returns: a watch id, which can be used in connection with
3427 * gst_element_remove_property_notify_watch() to remove the watch again.
3432 gst_element_add_property_deep_notify_watch (GstElement * element,
3433 const gchar * property_name, gboolean include_value)
3439 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3441 sep = (property_name != NULL) ? "::" : NULL;
3442 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3443 id = g_signal_connect (element, signal_name,
3444 G_CALLBACK (gst_element_property_deep_notify_cb),
3445 GINT_TO_POINTER (include_value));
3446 g_free (signal_name);
3452 * gst_element_remove_property_notify_watch:
3453 * @element: a #GstElement being watched for property changes
3454 * @watch_id: watch id to remove
3459 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3461 g_signal_handler_disconnect (element, watch_id);
3466 GstElement *element;
3467 GstElementCallAsyncFunc func;
3469 GDestroyNotify destroy_notify;
3470 } GstElementCallAsyncData;
3473 gst_element_call_async_func (gpointer data, gpointer user_data)
3475 GstElementCallAsyncData *async_data = data;
3477 async_data->func (async_data->element, async_data->user_data);
3478 if (async_data->destroy_notify)
3479 async_data->destroy_notify (async_data->user_data);
3480 gst_object_unref (async_data->element);
3481 g_free (async_data);
3485 * gst_element_call_async:
3486 * @element: a #GstElement
3487 * @func: Function to call asynchronously from another thread
3488 * @user_data: Data to pass to @func
3489 * @destroy_notify: GDestroyNotify for @user_data
3491 * Calls @func from another thread and passes @user_data to it. This is to be
3492 * used for cases when a state change has to be performed from a streaming
3493 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3496 * Calling those functions directly from the streaming thread will cause
3497 * deadlocks in many situations, as they might involve waiting for the
3498 * streaming thread to shut down from this very streaming thread.
3505 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3506 gpointer user_data, GDestroyNotify destroy_notify)
3508 GstElementCallAsyncData *async_data;
3510 g_return_if_fail (GST_IS_ELEMENT (element));
3512 async_data = g_new0 (GstElementCallAsyncData, 1);
3513 async_data->element = gst_object_ref (element);
3514 async_data->func = func;
3515 async_data->user_data = user_data;
3516 async_data->destroy_notify = destroy_notify;
3518 g_thread_pool_push (gst_element_pool, async_data, NULL);
3522 _priv_gst_element_cleanup (void)
3524 if (gst_element_pool) {
3525 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3526 gst_element_setup_thread_pool ();
3531 gst_make_element_message_details (const char *name, ...)
3533 GstStructure *structure;
3539 va_start (varargs, name);
3540 structure = gst_structure_new_valist ("details", name, varargs);