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.
26 * @short_description: Abstract base class for all pipeline elements
27 * @see_also: #GstElementFactory, #GstPad
29 * GstElement is the abstract base class needed to construct an element that
30 * can be used in a GStreamer pipeline. Please refer to the plugin writers
31 * guide for more information on creating #GstElement subclasses.
33 * The name of a #GstElement can be get with gst_element_get_name() and set with
34 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
35 * core when using the appropriate locking. Do not use this in plug-ins or
36 * applications in order to retain ABI compatibility.
38 * Elements can have pads (of the type #GstPad). These pads link to pads on
39 * other elements. #GstBuffer flow between these linked pads.
40 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
41 * and output (or source) pads.
42 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
43 * and gst_element_remove_pad().
45 * An existing pad of an element can be retrieved by name with
46 * gst_element_get_static_pad(). A new dynamic pad can be created using
47 * gst_element_request_pad() with a #GstPadTemplate.
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If the
72 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock selection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
80 #include "gst_private.h"
83 #include <gobject/gvaluecollector.h>
85 #include "gstelement.h"
86 #include "gstelementmetadata.h"
87 #include "gstenumtypes.h"
94 #include "gsttracerutils.h"
96 #include "gst-i18n-lib.h"
97 #include "glib-compat-private.h"
99 #ifndef GST_DISABLE_GST_DEBUG
100 #include "printf/printf.h"
103 /* Element signals and args */
119 static void gst_element_class_init (GstElementClass * klass);
120 static void gst_element_init (GstElement * element);
121 static void gst_element_base_class_init (gpointer g_class);
123 static void gst_element_constructed (GObject * object);
124 static void gst_element_dispose (GObject * object);
125 static void gst_element_finalize (GObject * object);
127 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
128 GstStateChange transition);
129 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
130 GstState * state, GstState * pending, GstClockTime timeout);
131 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
133 static gboolean gst_element_set_clock_func (GstElement * element,
135 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
136 static gboolean gst_element_post_message_default (GstElement * element,
137 GstMessage * message);
138 static void gst_element_set_context_default (GstElement * element,
139 GstContext * context);
141 static gboolean gst_element_default_send_event (GstElement * element,
143 static gboolean gst_element_default_query (GstElement * element,
146 static GstPadTemplate
147 * gst_element_class_get_request_pad_template (GstElementClass *
148 element_class, const gchar * name);
150 static void gst_element_call_async_func (gpointer data, gpointer user_data);
152 static GstObjectClass *parent_class = NULL;
153 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
155 static GThreadPool *gst_element_pool = NULL;
157 /* this is used in gstelementfactory.c:gst_element_register() */
158 GQuark __gst_elementclass_factory = 0;
161 gst_element_get_type (void)
163 static volatile gsize gst_element_type = 0;
165 if (g_once_init_enter (&gst_element_type)) {
167 static const GTypeInfo element_info = {
168 sizeof (GstElementClass),
169 gst_element_base_class_init,
170 NULL, /* base_class_finalize */
171 (GClassInitFunc) gst_element_class_init,
176 (GInstanceInitFunc) gst_element_init,
180 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
181 &element_info, G_TYPE_FLAG_ABSTRACT);
183 __gst_elementclass_factory =
184 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
185 g_once_init_leave (&gst_element_type, _type);
187 return gst_element_type;
191 gst_element_setup_thread_pool (void)
195 GST_DEBUG ("creating element thread pool");
197 g_thread_pool_new ((GFunc) gst_element_call_async_func, NULL, -1, FALSE,
200 g_critical ("could not alloc threadpool %s", err->message);
201 g_clear_error (&err);
206 gst_element_class_init (GstElementClass * klass)
208 GObjectClass *gobject_class;
210 gobject_class = (GObjectClass *) klass;
212 parent_class = g_type_class_peek_parent (klass);
215 * GstElement::pad-added:
216 * @gstelement: the object which received the signal
217 * @new_pad: the pad that has been added
219 * a new #GstPad has been added to the element. Note that this signal will
220 * usually be emitted from the context of the streaming thread. Also keep in
221 * mind that if you add new elements to the pipeline in the signal handler
222 * you will need to set them to the desired target state with
223 * gst_element_set_state() or gst_element_sync_state_with_parent().
225 gst_element_signals[PAD_ADDED] =
226 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
227 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
228 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
230 * GstElement::pad-removed:
231 * @gstelement: the object which received the signal
232 * @old_pad: the pad that has been removed
234 * a #GstPad has been removed from the element
236 gst_element_signals[PAD_REMOVED] =
237 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
238 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
239 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
241 * GstElement::no-more-pads:
242 * @gstelement: the object which received the signal
244 * This signals that the element will not generate more dynamic pads.
245 * Note that this signal will usually be emitted from the context of
246 * the streaming thread.
248 gst_element_signals[NO_MORE_PADS] =
249 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
250 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
251 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
253 gobject_class->dispose = gst_element_dispose;
254 gobject_class->finalize = gst_element_finalize;
255 gobject_class->constructed = gst_element_constructed;
257 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
258 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
259 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
260 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
261 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
262 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
263 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
264 klass->numpadtemplates = 0;
265 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
266 klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_default);
268 klass->elementfactory = NULL;
270 gst_element_setup_thread_pool ();
274 gst_element_base_class_init (gpointer g_class)
276 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
277 GList *node, *padtemplates;
279 /* Copy the element details here so elements can inherit the
280 * details from their base class and classes only need to set
281 * the details in class_init instead of base_init */
282 element_class->metadata =
283 element_class->metadata ? gst_structure_copy (element_class->metadata) :
284 gst_structure_new_empty ("metadata");
286 /* Copy the pad templates so elements inherit them
287 * from their base class but elements can add pad templates in class_init
288 * instead of base_init.
290 padtemplates = g_list_copy (element_class->padtemplates);
291 for (node = padtemplates; node != NULL; node = node->next) {
292 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
293 gst_object_ref (tmpl);
295 element_class->padtemplates = padtemplates;
297 /* set the factory, see gst_element_register() */
298 element_class->elementfactory =
299 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
300 __gst_elementclass_factory);
301 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
302 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
306 gst_element_init (GstElement * element)
308 GST_STATE (element) = GST_STATE_NULL;
309 GST_STATE_TARGET (element) = GST_STATE_NULL;
310 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
311 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
312 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
314 g_rec_mutex_init (&element->state_lock);
315 g_cond_init (&element->state_cond);
319 gst_element_constructed (GObject * object)
321 GST_TRACER_ELEMENT_NEW (GST_ELEMENT_CAST (object));
322 G_OBJECT_CLASS (parent_class)->constructed (object);
326 * gst_element_release_request_pad:
327 * @element: a #GstElement to release the request pad of.
328 * @pad: the #GstPad to release.
330 * Makes the element free the previously requested pad as obtained
331 * with gst_element_request_pad().
333 * This does not unref the pad. If the pad was created by using
334 * gst_element_request_pad(), gst_element_release_request_pad() needs to be
335 * followed by gst_object_unref() to free the @pad.
340 gst_element_release_request_pad (GstElement * element, GstPad * pad)
342 GstElementClass *oclass;
344 g_return_if_fail (GST_IS_ELEMENT (element));
345 g_return_if_fail (GST_IS_PAD (pad));
346 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
347 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
349 g_return_if_fail (GST_PAD_PARENT (pad) == element);
351 oclass = GST_ELEMENT_GET_CLASS (element);
353 /* if the element implements a custom release function we call that, else we
354 * simply remove the pad from the element */
355 if (oclass->release_pad)
356 oclass->release_pad (element, pad);
358 gst_element_remove_pad (element, pad);
362 * gst_element_provide_clock:
363 * @element: a #GstElement to query
365 * Get the clock provided by the given element.
366 * > An element is only required to provide a clock in the PAUSED
367 * > state. Some elements can provide a clock in other states.
369 * Returns: (transfer full) (nullable): the GstClock provided by the
370 * element or %NULL if no clock could be provided. Unref after usage.
375 gst_element_provide_clock (GstElement * element)
377 GstClock *result = NULL;
378 GstElementClass *oclass;
380 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
382 oclass = GST_ELEMENT_GET_CLASS (element);
384 if (oclass->provide_clock)
385 result = oclass->provide_clock (element);
391 gst_element_set_clock_func (GstElement * element, GstClock * clock)
395 GST_OBJECT_LOCK (element);
396 clock_p = &element->clock;
397 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
398 GST_OBJECT_UNLOCK (element);
404 * gst_element_set_clock:
405 * @element: a #GstElement to set the clock for.
406 * @clock: the #GstClock to set for the element.
408 * Sets the clock for the element. This function increases the
409 * refcount on the clock. Any previously set clock on the object
412 * Returns: %TRUE if the element accepted the clock. An element can refuse a
413 * clock when it, for example, is not able to slave its internal clock to the
414 * @clock or when it requires a specific clock to operate.
419 gst_element_set_clock (GstElement * element, GstClock * clock)
421 GstElementClass *oclass;
422 gboolean res = FALSE;
424 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
425 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
427 oclass = GST_ELEMENT_GET_CLASS (element);
429 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
431 if (oclass->set_clock)
432 res = oclass->set_clock (element, clock);
438 * gst_element_get_clock:
439 * @element: a #GstElement to get the clock of.
441 * Gets the currently configured clock of the element. This is the clock as was
442 * last set with gst_element_set_clock().
444 * Elements in a pipeline will only have their clock set when the
445 * pipeline is in the PLAYING state.
447 * Returns: (transfer full): the #GstClock of the element. unref after usage.
452 gst_element_get_clock (GstElement * element)
456 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
458 GST_OBJECT_LOCK (element);
459 if ((result = element->clock))
460 gst_object_ref (result);
461 GST_OBJECT_UNLOCK (element);
467 * gst_element_set_base_time:
468 * @element: a #GstElement.
469 * @time: the base time to set.
471 * Set the base time of an element. See gst_element_get_base_time().
476 gst_element_set_base_time (GstElement * element, GstClockTime time)
480 g_return_if_fail (GST_IS_ELEMENT (element));
482 GST_OBJECT_LOCK (element);
483 old = element->base_time;
484 element->base_time = time;
485 GST_OBJECT_UNLOCK (element);
487 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
488 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
489 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
493 * gst_element_get_base_time:
494 * @element: a #GstElement.
496 * Returns the base time of the element. The base time is the
497 * absolute time of the clock when this element was last put to
498 * PLAYING. Subtracting the base time from the clock time gives
499 * the running time of the element.
501 * Returns: the base time of the element.
506 gst_element_get_base_time (GstElement * element)
510 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
512 GST_OBJECT_LOCK (element);
513 result = element->base_time;
514 GST_OBJECT_UNLOCK (element);
520 * gst_element_set_start_time:
521 * @element: a #GstElement.
522 * @time: the base time to set.
524 * Set the start time of an element. The start time of the element is the
525 * running time of the element when it last went to the PAUSED state. In READY
526 * or after a flushing seek, it is set to 0.
528 * Toplevel elements like #GstPipeline will manage the start_time and
529 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
530 * on such a toplevel element will disable the distribution of the base_time to
531 * the children and can be useful if the application manages the base_time
532 * itself, for example if you want to synchronize capture from multiple
533 * pipelines, and you can also ensure that the pipelines have the same clock.
538 gst_element_set_start_time (GstElement * element, GstClockTime time)
542 g_return_if_fail (GST_IS_ELEMENT (element));
544 GST_OBJECT_LOCK (element);
545 old = GST_ELEMENT_START_TIME (element);
546 GST_ELEMENT_START_TIME (element) = time;
547 GST_OBJECT_UNLOCK (element);
549 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
550 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
551 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
555 * gst_element_get_start_time:
556 * @element: a #GstElement.
558 * Returns the start time of the element. The start time is the
559 * running time of the clock when this element was last put to PAUSED.
561 * Usually the start_time is managed by a toplevel element such as
566 * Returns: the start time of the element.
569 gst_element_get_start_time (GstElement * element)
573 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
575 GST_OBJECT_LOCK (element);
576 result = GST_ELEMENT_START_TIME (element);
577 GST_OBJECT_UNLOCK (element);
584 * gst_element_set_index:
585 * @element: a #GstElement.
586 * @index: (transfer none): a #GstIndex.
588 * Set @index on the element. The refcount of the index
589 * will be increased, any previously set index is unreffed.
594 gst_element_set_index (GstElement * element, GstIndex * index)
596 GstElementClass *oclass;
598 g_return_if_fail (GST_IS_ELEMENT (element));
599 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
601 oclass = GST_ELEMENT_GET_CLASS (element);
603 if (oclass->set_index)
604 oclass->set_index (element, index);
608 * gst_element_get_index:
609 * @element: a #GstElement.
611 * Gets the index from the element.
613 * Returns: (transfer full) (nullable): a #GstIndex or %NULL when no
614 * index was set on the element. unref after usage.
619 gst_element_get_index (GstElement * element)
621 GstElementClass *oclass;
622 GstIndex *result = NULL;
624 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
626 oclass = GST_ELEMENT_GET_CLASS (element);
628 if (oclass->get_index)
629 result = oclass->get_index (element);
636 * gst_element_add_pad:
637 * @element: a #GstElement to add the pad to.
638 * @pad: (transfer floating): the #GstPad to add to the element.
640 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
641 * see gst_object_set_parent() for refcounting information.
643 * Pads are not automatically activated so elements should perform the needed
644 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
645 * state. See gst_pad_set_active() for more information about activating pads.
647 * The pad and the element should be unlocked when calling this function.
649 * This function will emit the #GstElement::pad-added signal on the element.
651 * Returns: %TRUE if the pad could be added. This function can fail when
652 * a pad with the same name already existed or the pad already had another
658 gst_element_add_pad (GstElement * element, GstPad * pad)
663 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
664 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
666 /* locking pad to look at the name */
667 GST_OBJECT_LOCK (pad);
668 pad_name = g_strdup (GST_PAD_NAME (pad));
669 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
670 GST_STR_NULL (pad_name));
671 active = GST_PAD_IS_ACTIVE (pad);
672 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
673 GST_OBJECT_UNLOCK (pad);
675 /* then check to see if there's already a pad by that name here */
676 GST_OBJECT_LOCK (element);
677 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
680 /* try to set the pad's parent */
681 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
682 GST_OBJECT_CAST (element))))
685 /* check for active pads */
686 if (!active && (GST_STATE (element) > GST_STATE_READY ||
687 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
688 g_warning ("adding inactive pad '%s' to running element '%s', you need to "
689 "use gst_pad_set_active(pad,TRUE) before adding it.",
690 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
691 gst_pad_set_active (pad, TRUE);
696 /* add it to the list */
697 switch (gst_pad_get_direction (pad)) {
699 element->srcpads = g_list_append (element->srcpads, pad);
700 element->numsrcpads++;
703 element->sinkpads = g_list_append (element->sinkpads, pad);
704 element->numsinkpads++;
709 element->pads = g_list_append (element->pads, pad);
711 element->pads_cookie++;
712 GST_OBJECT_UNLOCK (element);
714 /* emit the PAD_ADDED signal */
715 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
716 GST_TRACER_ELEMENT_ADD_PAD (element, pad);
722 g_critical ("Padname %s is not unique in element %s, not adding",
723 pad_name, GST_ELEMENT_NAME (element));
724 GST_OBJECT_UNLOCK (element);
726 gst_object_ref_sink (pad);
727 gst_object_unref (pad);
733 ("Pad %s already has parent when trying to add to element %s",
734 pad_name, GST_ELEMENT_NAME (element));
735 GST_OBJECT_UNLOCK (element);
741 GST_OBJECT_LOCK (pad);
743 ("Trying to add pad %s to element %s, but it has no direction",
744 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
745 GST_OBJECT_UNLOCK (pad);
746 GST_OBJECT_UNLOCK (element);
752 * gst_element_remove_pad:
753 * @element: a #GstElement to remove pad from.
754 * @pad: (transfer full): the #GstPad to remove from the element.
756 * Removes @pad from @element. @pad will be destroyed if it has not been
757 * referenced elsewhere using gst_object_unparent().
759 * This function is used by plugin developers and should not be used
760 * by applications. Pads that were dynamically requested from elements
761 * with gst_element_request_pad() should be released with the
762 * gst_element_release_request_pad() function instead.
764 * Pads are not automatically deactivated so elements should perform the needed
765 * steps to deactivate the pad in case this pad is removed in the PAUSED or
766 * PLAYING state. See gst_pad_set_active() for more information about
769 * The pad and the element should be unlocked when calling this function.
771 * This function will emit the #GstElement::pad-removed signal on the element.
773 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
774 * pad does not belong to the provided element.
779 gst_element_remove_pad (GstElement * element, GstPad * pad)
783 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
784 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
786 /* locking pad to look at the name and parent */
787 GST_OBJECT_LOCK (pad);
788 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
789 GST_STR_NULL (GST_PAD_NAME (pad)));
791 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
793 GST_OBJECT_UNLOCK (pad);
796 if ((peer = gst_pad_get_peer (pad))) {
797 /* window for MT unsafeness, someone else could unlink here
798 * and then we call unlink with wrong pads. The unlink
799 * function would catch this and safely return failed. */
800 if (GST_PAD_IS_SRC (pad))
801 gst_pad_unlink (pad, peer);
803 gst_pad_unlink (peer, pad);
805 gst_object_unref (peer);
808 GST_OBJECT_LOCK (element);
809 /* remove it from the list */
810 switch (gst_pad_get_direction (pad)) {
812 element->srcpads = g_list_remove (element->srcpads, pad);
813 element->numsrcpads--;
816 element->sinkpads = g_list_remove (element->sinkpads, pad);
817 element->numsinkpads--;
820 g_critical ("Removing pad without direction???");
823 element->pads = g_list_remove (element->pads, pad);
825 element->pads_cookie++;
826 GST_OBJECT_UNLOCK (element);
828 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
829 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
830 GST_TRACER_ELEMENT_REMOVE_PAD (element, pad);
831 gst_object_unparent (GST_OBJECT_CAST (pad));
838 /* locking order is element > pad */
839 GST_OBJECT_UNLOCK (pad);
841 GST_OBJECT_LOCK (element);
842 GST_OBJECT_LOCK (pad);
843 g_critical ("Padname %s:%s does not belong to element %s when removing",
844 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
845 GST_OBJECT_UNLOCK (pad);
846 GST_OBJECT_UNLOCK (element);
852 * gst_element_no_more_pads:
853 * @element: a #GstElement
855 * Use this function to signal that the element does not expect any more pads
856 * to show up in the current pipeline. This function should be called whenever
857 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
858 * pad templates use this in combination with autopluggers to figure out that
859 * the element is done initializing its pads.
861 * This function emits the #GstElement::no-more-pads signal.
866 gst_element_no_more_pads (GstElement * element)
868 g_return_if_fail (GST_IS_ELEMENT (element));
870 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
874 pad_compare_name (GstPad * pad1, const gchar * name)
878 GST_OBJECT_LOCK (pad1);
879 result = strcmp (GST_PAD_NAME (pad1), name);
880 GST_OBJECT_UNLOCK (pad1);
886 * gst_element_get_static_pad:
887 * @element: a #GstElement to find a static pad of.
888 * @name: the name of the static #GstPad to retrieve.
890 * Retrieves a pad from @element by name. This version only retrieves
891 * already-existing (i.e. 'static') pads.
893 * Returns: (transfer full) (nullable): the requested #GstPad if
894 * found, otherwise %NULL. unref after usage.
899 gst_element_get_static_pad (GstElement * element, const gchar * name)
902 GstPad *result = NULL;
904 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
905 g_return_val_if_fail (name != NULL, NULL);
907 GST_OBJECT_LOCK (element);
909 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
911 result = GST_PAD_CAST (find->data);
912 gst_object_ref (result);
915 if (result == NULL) {
916 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
917 name, GST_ELEMENT_NAME (element));
919 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
920 GST_ELEMENT_NAME (element), name);
922 GST_OBJECT_UNLOCK (element);
928 gst_element_is_valid_request_template_name (const gchar * templ_name,
932 const gchar *templ_name_ptr, *name_ptr;
933 gboolean next_specifier;
934 guint templ_postfix_len = 0, name_postfix_len = 0;
936 g_return_val_if_fail (templ_name != NULL, FALSE);
937 g_return_val_if_fail (name != NULL, FALSE);
939 /* Is this the template name? */
940 if (strcmp (templ_name, name) == 0)
943 /* otherwise check all the specifiers */
945 /* Because of sanity checks in gst_pad_template_new(), we know that %s
946 * and %d and %u, occurring at the template_name */
947 templ_name_ptr = strchr (templ_name, '%');
949 /* check characters ahead of the specifier */
950 if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
951 || strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
955 /* %s is not allowed for multiple specifiers, just a single specifier can be
956 * accepted in gst_pad_template_new() and can not be mixed with other
957 * specifier '%u' and '%d' */
958 if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
962 name_ptr = name + (templ_name_ptr - templ_name);
964 /* search next specifier, each of specifier should be separated by '_' */
965 templ_name = strchr (templ_name_ptr, '_');
966 name = strchr (name_ptr, '_');
968 /* don't match the number of specifiers */
969 if ((templ_name && !name) || (!templ_name && name))
972 if (templ_name && name)
973 next_specifier = TRUE;
975 next_specifier = FALSE;
977 /* check characters followed by the specifier */
978 if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
979 if (next_specifier) {
980 templ_postfix_len = templ_name - (templ_name_ptr + 2);
981 name_postfix_len = name - name_ptr;
983 templ_postfix_len = strlen (templ_name_ptr + 2);
984 name_postfix_len = strlen (name_ptr);
987 if (strncmp (templ_name_ptr + 2,
988 name_ptr + name_postfix_len - templ_postfix_len,
989 templ_postfix_len) != 0) {
994 /* verify the specifier */
995 if (*(name_ptr) == '%') {
998 len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
1000 if (strncmp (name_ptr, templ_name_ptr, len) != 0)
1004 const gchar *specifier;
1005 gchar *target = NULL;
1007 /* extract specifier when it has postfix characters */
1008 if (name_postfix_len > templ_postfix_len) {
1009 target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
1011 specifier = target ? target : name_ptr;
1013 if (*(templ_name_ptr + 1) == 'd') {
1017 tmp = g_ascii_strtoll (specifier, &endptr, 10);
1018 if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
1021 } else if (*(templ_name_ptr + 1) == 'u') {
1025 tmp = g_ascii_strtoull (specifier, &endptr, 10);
1026 if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
1033 /* otherwise we increment these from NULL to 1 */
1034 if (next_specifier) {
1038 } while (next_specifier);
1044 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
1045 const gchar * name, const GstCaps * caps)
1047 GstPad *newpad = NULL;
1048 GstElementClass *oclass;
1050 oclass = GST_ELEMENT_GET_CLASS (element);
1052 #ifndef G_DISABLE_CHECKS
1053 /* Some sanity checking here */
1057 g_return_val_if_fail (gst_element_is_valid_request_template_name
1058 (templ->name_template, name), NULL);
1060 pad = gst_element_get_static_pad (element, name);
1062 gst_object_unref (pad);
1063 /* FIXME 2.0: Change this to g_return_val_if_fail() */
1064 g_critical ("Element %s already has a pad named %s, the behaviour of "
1065 " gst_element_get_request_pad() for existing pads is undefined!",
1066 GST_ELEMENT_NAME (element), name);
1071 if (oclass->request_new_pad)
1072 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1075 gst_object_ref (newpad);
1081 * gst_element_get_request_pad:
1082 * @element: a #GstElement to find a request pad of.
1083 * @name: the name of the request #GstPad to retrieve.
1085 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1086 * retrieves request pads. The pad should be released with
1087 * gst_element_release_request_pad().
1089 * This method is slower than manually getting the pad template and calling
1090 * gst_element_request_pad() if the pads should have a specific name (e.g.
1091 * @name is "src_1" instead of "src_\%u").
1093 * Returns: (transfer full) (nullable): requested #GstPad if found,
1094 * otherwise %NULL. Release after usage.
1097 gst_element_get_request_pad (GstElement * element, const gchar * name)
1099 GstPadTemplate *templ = NULL;
1101 const gchar *req_name = NULL;
1102 gboolean templ_found = FALSE;
1104 GstElementClass *class;
1106 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1107 g_return_val_if_fail (name != NULL, NULL);
1109 class = GST_ELEMENT_GET_CLASS (element);
1111 templ = gst_element_class_get_request_pad_template (class, name);
1113 req_name = strstr (name, "%") ? NULL : name;
1116 /* there is no % in the name, try to find a matching template */
1117 list = class->padtemplates;
1118 while (!templ_found && list) {
1119 templ = (GstPadTemplate *) list->data;
1120 if (templ->presence == GST_PAD_REQUEST) {
1121 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1122 templ->name_template);
1123 if (gst_element_is_valid_request_template_name (templ->name_template,
1137 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1143 * gst_element_request_pad: (virtual request_new_pad)
1144 * @element: a #GstElement to find a request pad of.
1145 * @templ: a #GstPadTemplate of which we want a pad of.
1146 * @name: (transfer none) (allow-none): the name of the request #GstPad
1147 * to retrieve. Can be %NULL.
1148 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1149 * request. Can be %NULL.
1151 * Retrieves a request pad from the element according to the provided template.
1152 * Pad templates can be looked up using
1153 * gst_element_factory_get_static_pad_templates().
1155 * The pad should be released with gst_element_release_request_pad().
1157 * Returns: (transfer full) (nullable): requested #GstPad if found,
1158 * otherwise %NULL. Release after usage.
1161 gst_element_request_pad (GstElement * element,
1162 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1164 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1165 g_return_val_if_fail (templ != NULL, NULL);
1166 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1168 return _gst_element_request_pad (element, templ, name, caps);
1171 static GstIterator *
1172 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1174 GstIterator *result;
1176 GST_OBJECT_LOCK (element);
1177 result = gst_iterator_new_list (GST_TYPE_PAD,
1178 GST_OBJECT_GET_LOCK (element),
1179 &element->pads_cookie, padlist, (GObject *) element, NULL);
1180 GST_OBJECT_UNLOCK (element);
1186 * gst_element_iterate_pads:
1187 * @element: a #GstElement to iterate pads of.
1189 * Retrieves an iterator of @element's pads. The iterator should
1190 * be freed after usage. Also more specialized iterators exists such as
1191 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1193 * The order of pads returned by the iterator will be the order in which
1194 * the pads were added to the element.
1196 * Returns: (transfer full): the #GstIterator of #GstPad.
1201 gst_element_iterate_pads (GstElement * element)
1203 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1205 return gst_element_iterate_pad_list (element, &element->pads);
1209 * gst_element_iterate_src_pads:
1210 * @element: a #GstElement.
1212 * Retrieves an iterator of @element's source pads.
1214 * The order of pads returned by the iterator will be the order in which
1215 * the pads were added to the element.
1217 * Returns: (transfer full): the #GstIterator of #GstPad.
1222 gst_element_iterate_src_pads (GstElement * element)
1224 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1226 return gst_element_iterate_pad_list (element, &element->srcpads);
1230 * gst_element_iterate_sink_pads:
1231 * @element: a #GstElement.
1233 * Retrieves an iterator of @element's sink pads.
1235 * The order of pads returned by the iterator will be the order in which
1236 * the pads were added to the element.
1238 * Returns: (transfer full): the #GstIterator of #GstPad.
1243 gst_element_iterate_sink_pads (GstElement * element)
1245 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1247 return gst_element_iterate_pad_list (element, &element->sinkpads);
1251 gst_element_do_foreach_pad (GstElement * element,
1252 GstElementForeachPadFunc func, gpointer user_data,
1253 GList ** p_pads, guint16 * p_npads)
1255 gboolean ret = TRUE;
1260 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1261 g_return_val_if_fail (func != NULL, FALSE);
1263 GST_OBJECT_LOCK (element);
1265 pads = g_newa (GstPad *, n_pads + 1);
1266 for (l = *p_pads, i = 0; l != NULL; l = l->next) {
1267 g_assert (i < n_pads);
1268 pads[i++] = gst_object_ref (l->data);
1270 GST_OBJECT_UNLOCK (element);
1275 for (i = 0; i < n_pads; ++i) {
1276 ret = func (element, pads[i], user_data);
1281 for (i = 0; i < n_pads; ++i)
1282 gst_object_unref (pads[i]);
1288 * gst_element_foreach_sink_pad:
1289 * @element: a #GstElement to iterate sink pads of
1290 * @func: (scope call): function to call for each sink pad
1291 * @user_data: (closure): user data passed to @func
1293 * Call @func with @user_data for each of @element's sink pads. @func will be
1294 * called exactly once for each sink pad that exists at the time of this call,
1295 * unless one of the calls to @func returns %FALSE in which case we will stop
1296 * iterating pads and return early. If new sink pads are added or sink pads
1297 * are removed while the sink pads are being iterated, this will not be taken
1298 * into account until next time this function is used.
1300 * Returns: %FALSE if @element had no sink pads or if one of the calls to @func
1306 gst_element_foreach_sink_pad (GstElement * element,
1307 GstElementForeachPadFunc func, gpointer user_data)
1309 return gst_element_do_foreach_pad (element, func, user_data,
1310 &element->sinkpads, &element->numsinkpads);
1314 * gst_element_foreach_src_pad:
1315 * @element: a #GstElement to iterate source pads of
1316 * @func: (scope call): function to call for each source pad
1317 * @user_data: (closure): user data passed to @func
1319 * Call @func with @user_data for each of @element's source pads. @func will be
1320 * called exactly once for each source pad that exists at the time of this call,
1321 * unless one of the calls to @func returns %FALSE in which case we will stop
1322 * iterating pads and return early. If new source pads are added or source pads
1323 * are removed while the source pads are being iterated, this will not be taken
1324 * into account until next time this function is used.
1326 * Returns: %FALSE if @element had no source pads or if one of the calls
1327 * to @func returned %FALSE.
1332 gst_element_foreach_src_pad (GstElement * element,
1333 GstElementForeachPadFunc func, gpointer user_data)
1335 return gst_element_do_foreach_pad (element, func, user_data,
1336 &element->srcpads, &element->numsrcpads);
1340 * gst_element_foreach_pad:
1341 * @element: a #GstElement to iterate pads of
1342 * @func: (scope call): function to call for each pad
1343 * @user_data: (closure): user data passed to @func
1345 * Call @func with @user_data for each of @element's pads. @func will be called
1346 * exactly once for each pad that exists at the time of this call, unless
1347 * one of the calls to @func returns %FALSE in which case we will stop
1348 * iterating pads and return early. If new pads are added or pads are removed
1349 * while pads are being iterated, this will not be taken into account until
1350 * next time this function is used.
1352 * Returns: %FALSE if @element had no pads or if one of the calls to @func
1358 gst_element_foreach_pad (GstElement * element, GstElementForeachPadFunc func,
1361 return gst_element_do_foreach_pad (element, func, user_data,
1362 &element->pads, &element->numpads);
1366 * gst_element_class_add_pad_template:
1367 * @klass: the #GstElementClass to add the pad template to.
1368 * @templ: (transfer floating): a #GstPadTemplate to add to the element class.
1370 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1371 * functions of classes. If a pad template with the same name as an already
1372 * existing one is added the old one is replaced by the new one.
1374 * @templ's reference count will be incremented, and any floating
1375 * reference will be removed (see gst_object_ref_sink())
1379 gst_element_class_add_pad_template (GstElementClass * klass,
1380 GstPadTemplate * templ)
1382 GList *template_list = klass->padtemplates;
1384 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1385 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1387 /* If we already have a pad template with the same name replace the
1389 while (template_list) {
1390 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1392 /* Found pad with the same name, replace and return */
1393 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1394 gst_object_ref_sink (padtempl);
1395 gst_object_unref (padtempl);
1396 template_list->data = templ;
1399 template_list = g_list_next (template_list);
1402 /* Take ownership of the floating ref */
1403 gst_object_ref_sink (templ);
1405 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1406 klass->numpadtemplates++;
1410 * gst_element_class_add_static_pad_template:
1411 * @klass: the #GstElementClass to add the pad template to.
1412 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1414 * Adds a pad template to an element class based on the static pad template
1415 * @templ. This is mainly used in the _class_init functions of element
1416 * implementations. If a pad template with the same name already exists,
1417 * the old one is replaced by the new one.
1422 gst_element_class_add_static_pad_template (GstElementClass * klass,
1423 GstStaticPadTemplate * static_templ)
1425 gst_element_class_add_pad_template (klass,
1426 gst_static_pad_template_get (static_templ));
1430 * gst_element_class_add_static_pad_template_with_gtype:
1431 * @klass: the #GstElementClass to add the pad template to.
1432 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1433 * @pad_type: The #GType of the pad to create
1435 * Adds a pad template to an element class based on the static pad template
1436 * @templ. This is mainly used in the _class_init functions of element
1437 * implementations. If a pad template with the same name already exists,
1438 * the old one is replaced by the new one.
1443 gst_element_class_add_static_pad_template_with_gtype (GstElementClass * klass,
1444 GstStaticPadTemplate * static_templ, GType pad_type)
1446 gst_element_class_add_pad_template (klass,
1447 gst_pad_template_new_from_static_pad_template_with_gtype (static_templ,
1452 * gst_element_class_add_metadata:
1453 * @klass: class to set metadata for
1454 * @key: the key to set
1455 * @value: the value to set
1457 * Set @key with @value as metadata in @klass.
1460 gst_element_class_add_metadata (GstElementClass * klass,
1461 const gchar * key, const gchar * value)
1463 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1464 g_return_if_fail (key != NULL);
1465 g_return_if_fail (value != NULL);
1467 gst_structure_set ((GstStructure *) klass->metadata,
1468 key, G_TYPE_STRING, value, NULL);
1472 * gst_element_class_add_static_metadata:
1473 * @klass: class to set metadata for
1474 * @key: the key to set
1475 * @value: the value to set
1477 * Set @key with @value as metadata in @klass.
1479 * Same as gst_element_class_add_metadata(), but @value must be a static string
1480 * or an inlined string, as it will not be copied. (GStreamer plugins will
1481 * be made resident once loaded, so this function can be used even from
1482 * dynamically loaded plugins.)
1485 gst_element_class_add_static_metadata (GstElementClass * klass,
1486 const gchar * key, const gchar * value)
1488 GValue val = G_VALUE_INIT;
1490 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1491 g_return_if_fail (key != NULL);
1492 g_return_if_fail (value != NULL);
1494 g_value_init (&val, G_TYPE_STRING);
1495 g_value_set_static_string (&val, value);
1496 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1500 * gst_element_class_set_metadata:
1501 * @klass: class to set metadata for
1502 * @longname: The long English name of the element. E.g. "File Sink"
1503 * @classification: String describing the type of element, as an unordered list
1504 * separated with slashes ('/'). See draft-klass.txt of the design docs
1505 * for more details and common types. E.g: "Sink/File"
1506 * @description: Sentence describing the purpose of the element.
1507 * E.g: "Write stream to a file"
1508 * @author: Name and contact details of the author(s). Use \n to separate
1509 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1511 * Sets the detailed information for a #GstElementClass.
1512 * > This function is for use in _class_init functions only.
1515 gst_element_class_set_metadata (GstElementClass * klass,
1516 const gchar * longname, const gchar * classification,
1517 const gchar * description, const gchar * author)
1519 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1520 g_return_if_fail (longname != NULL && *longname != '\0');
1521 g_return_if_fail (classification != NULL && *classification != '\0');
1522 g_return_if_fail (description != NULL && *description != '\0');
1523 g_return_if_fail (author != NULL && *author != '\0');
1525 gst_structure_id_set ((GstStructure *) klass->metadata,
1526 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1527 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1528 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1529 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1533 * gst_element_class_set_static_metadata:
1534 * @klass: class to set metadata for
1535 * @longname: The long English name of the element. E.g. "File Sink"
1536 * @classification: String describing the type of element, as an unordered list
1537 * separated with slashes ('/'). See draft-klass.txt of the design docs
1538 * for more details and common types. E.g: "Sink/File"
1539 * @description: Sentence describing the purpose of the element.
1540 * E.g: "Write stream to a file"
1541 * @author: Name and contact details of the author(s). Use \n to separate
1542 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1544 * Sets the detailed information for a #GstElementClass.
1546 * > This function is for use in _class_init functions only.
1548 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1549 * @description, and @author must be static strings or inlined strings, as
1550 * they will not be copied. (GStreamer plugins will be made resident once
1551 * loaded, so this function can be used even from dynamically loaded plugins.)
1554 gst_element_class_set_static_metadata (GstElementClass * klass,
1555 const gchar * longname, const gchar * classification,
1556 const gchar * description, const gchar * author)
1558 GstStructure *s = (GstStructure *) klass->metadata;
1559 GValue val = G_VALUE_INIT;
1561 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1562 g_return_if_fail (longname != NULL && *longname != '\0');
1563 g_return_if_fail (classification != NULL && *classification != '\0');
1564 g_return_if_fail (description != NULL && *description != '\0');
1565 g_return_if_fail (author != NULL && *author != '\0');
1567 g_value_init (&val, G_TYPE_STRING);
1569 g_value_set_static_string (&val, longname);
1570 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1572 g_value_set_static_string (&val, classification);
1573 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1575 g_value_set_static_string (&val, description);
1576 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1579 g_value_set_static_string (&val, author);
1580 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1584 * gst_element_class_get_metadata:
1585 * @klass: class to get metadata for
1586 * @key: the key to get
1588 * Get metadata with @key in @klass.
1590 * Returns: the metadata for @key.
1593 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1595 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1596 g_return_val_if_fail (key != NULL, NULL);
1598 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1602 * gst_element_get_metadata:
1603 * @element: class to get metadata for
1604 * @key: the key to get
1606 * Get metadata with @key in @klass.
1608 * Returns: the metadata for @key.
1613 gst_element_get_metadata (GstElement * element, const gchar * key)
1615 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1616 g_return_val_if_fail (key != NULL, NULL);
1618 return gst_element_class_get_metadata (GST_ELEMENT_GET_CLASS (element), key);
1622 * gst_element_class_get_pad_template_list:
1623 * @element_class: a #GstElementClass to get pad templates of.
1625 * Retrieves a list of the pad templates associated with @element_class. The
1626 * list must not be modified by the calling code.
1627 * > If you use this function in the #GInstanceInitFunc of an object class
1628 * > that has subclasses, make sure to pass the g_class parameter of the
1629 * > #GInstanceInitFunc here.
1631 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1635 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1637 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1639 return element_class->padtemplates;
1643 * gst_element_get_pad_template_list:
1644 * @element: a #GstElement to get pad templates of.
1646 * Retrieves a list of the pad templates associated with @element. The
1647 * list must not be modified by the calling code.
1649 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1655 gst_element_get_pad_template_list (GstElement * element)
1657 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1660 gst_element_class_get_pad_template_list (GST_ELEMENT_GET_CLASS (element));
1664 * gst_element_class_get_pad_template:
1665 * @element_class: a #GstElementClass to get the pad template of.
1666 * @name: the name of the #GstPadTemplate to get.
1668 * Retrieves a padtemplate from @element_class with the given name.
1669 * > If you use this function in the #GInstanceInitFunc of an object class
1670 * > that has subclasses, make sure to pass the g_class parameter of the
1671 * > #GInstanceInitFunc here.
1673 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1674 * given name, or %NULL if none was found. No unreferencing is
1678 gst_element_class_get_pad_template (GstElementClass *
1679 element_class, const gchar * name)
1683 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1684 g_return_val_if_fail (name != NULL, NULL);
1686 padlist = element_class->padtemplates;
1689 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1691 if (strcmp (padtempl->name_template, name) == 0)
1694 padlist = g_list_next (padlist);
1701 * gst_element_get_pad_template:
1702 * @element: a #GstElement to get the pad template of.
1703 * @name: the name of the #GstPadTemplate to get.
1705 * Retrieves a padtemplate from @element with the given name.
1707 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1708 * given name, or %NULL if none was found. No unreferencing is
1714 gst_element_get_pad_template (GstElement * element, const gchar * name)
1716 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1717 g_return_val_if_fail (name != NULL, NULL);
1719 return gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (element),
1723 static GstPadTemplate *
1724 gst_element_class_get_request_pad_template (GstElementClass *
1725 element_class, const gchar * name)
1727 GstPadTemplate *tmpl;
1729 tmpl = gst_element_class_get_pad_template (element_class, name);
1730 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1736 /* get a random pad on element of the given direction.
1737 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1740 gst_element_get_random_pad (GstElement * element,
1741 gboolean need_linked, GstPadDirection dir)
1743 GstPad *result = NULL;
1746 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1750 GST_OBJECT_LOCK (element);
1751 pads = element->srcpads;
1754 GST_OBJECT_LOCK (element);
1755 pads = element->sinkpads;
1758 goto wrong_direction;
1760 for (; pads; pads = g_list_next (pads)) {
1761 GstPad *pad = GST_PAD_CAST (pads->data);
1763 GST_OBJECT_LOCK (pad);
1764 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1765 GST_DEBUG_PAD_NAME (pad));
1767 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1768 /* if we require a linked pad, and it is not linked, continue the
1770 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1771 GST_DEBUG_PAD_NAME (pad));
1772 GST_OBJECT_UNLOCK (pad);
1775 /* found a pad, stop search */
1776 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1777 GST_DEBUG_PAD_NAME (pad));
1778 GST_OBJECT_UNLOCK (pad);
1784 gst_object_ref (result);
1786 GST_OBJECT_UNLOCK (element);
1790 /* ERROR handling */
1793 g_warning ("unknown pad direction %d", dir);
1799 gst_element_default_send_event (GstElement * element, GstEvent * event)
1801 gboolean result = FALSE;
1804 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1805 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1806 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1809 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1810 "pushing %s event to random %s pad %s:%s",
1811 GST_EVENT_TYPE_NAME (event),
1812 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1813 GST_DEBUG_PAD_NAME (pad));
1815 result = gst_pad_send_event (pad, event);
1816 gst_object_unref (pad);
1818 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1819 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1820 gst_event_unref (event);
1826 * gst_element_send_event:
1827 * @element: a #GstElement to send the event to.
1828 * @event: (transfer full): the #GstEvent to send to the element.
1830 * Sends an event to an element. If the element doesn't implement an
1831 * event handler, the event will be pushed on a random linked sink pad for
1832 * downstream events or a random linked source pad for upstream events.
1834 * This function takes ownership of the provided event so you should
1835 * gst_event_ref() it if you want to reuse the event after this call.
1839 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1840 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1843 gst_element_send_event (GstElement * element, GstEvent * event)
1845 GstElementClass *oclass;
1846 gboolean result = FALSE;
1848 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1849 g_return_val_if_fail (event != NULL, FALSE);
1851 oclass = GST_ELEMENT_GET_CLASS (element);
1853 GST_STATE_LOCK (element);
1854 if (oclass->send_event) {
1855 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1856 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1857 result = oclass->send_event (element, event);
1859 gst_event_unref (event);
1861 GST_STATE_UNLOCK (element);
1868 * @element: a #GstElement to send the event to.
1869 * @rate: The new playback rate
1870 * @format: The format of the seek values
1871 * @flags: The optional seek flags.
1872 * @start_type: The type and flags for the new start position
1873 * @start: The value of the new start position
1874 * @stop_type: The type and flags for the new stop position
1875 * @stop: The value of the new stop position
1877 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1878 * the parameters. The seek event is sent to the element using
1879 * gst_element_send_event().
1883 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1884 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1887 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1888 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1889 GstSeekType stop_type, gint64 stop)
1894 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1897 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1899 result = gst_element_send_event (element, event);
1905 gst_element_default_query (GstElement * element, GstQuery * query)
1907 gboolean result = FALSE;
1910 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1912 result = gst_pad_query (pad, query);
1914 gst_object_unref (pad);
1916 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1918 GstPad *peer = gst_pad_get_peer (pad);
1921 result = gst_pad_query (peer, query);
1923 gst_object_unref (peer);
1925 gst_object_unref (pad);
1932 * gst_element_query:
1933 * @element: a #GstElement to perform the query on.
1934 * @query: (transfer none): the #GstQuery.
1936 * Performs a query on the given element.
1938 * For elements that don't implement a query handler, this function
1939 * forwards the query to a random srcpad or to the peer of a
1940 * random linked sinkpad of this element.
1942 * Please note that some queries might need a running pipeline to work.
1944 * Returns: %TRUE if the query could be performed.
1949 gst_element_query (GstElement * element, GstQuery * query)
1951 GstElementClass *klass;
1952 gboolean res = FALSE;
1954 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1955 g_return_val_if_fail (query != NULL, FALSE);
1957 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1959 klass = GST_ELEMENT_GET_CLASS (element);
1961 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1962 GST_ELEMENT_NAME (element));
1963 res = klass->query (element, query);
1966 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1971 gst_element_post_message_default (GstElement * element, GstMessage * message)
1974 gboolean result = FALSE;
1976 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1977 g_return_val_if_fail (message != NULL, FALSE);
1979 GST_OBJECT_LOCK (element);
1982 if (G_UNLIKELY (bus == NULL))
1985 gst_object_ref (bus);
1986 GST_OBJECT_UNLOCK (element);
1988 /* we release the element lock when posting the message so that any
1989 * (synchronous) message handlers can operate on the element */
1990 result = gst_bus_post (bus, message);
1991 gst_object_unref (bus);
1998 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1999 "not posting message %p: no bus", message);
2000 GST_OBJECT_UNLOCK (element);
2001 gst_message_unref (message);
2007 * gst_element_post_message:
2008 * @element: a #GstElement posting the message
2009 * @message: (transfer full): a #GstMessage to post
2011 * Post a message on the element's #GstBus. This function takes ownership of the
2012 * message; if you want to access the message after this call, you should add an
2013 * additional reference before calling.
2015 * Returns: %TRUE if the message was successfully posted. The function returns
2016 * %FALSE if the element did not have a bus.
2021 gst_element_post_message (GstElement * element, GstMessage * message)
2023 GstElementClass *klass;
2024 gboolean res = FALSE;
2026 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2027 g_return_val_if_fail (message != NULL, FALSE);
2029 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
2031 klass = GST_ELEMENT_GET_CLASS (element);
2032 if (klass->post_message)
2033 res = klass->post_message (element, message);
2035 gst_message_unref (message);
2037 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
2042 * _gst_element_error_printf:
2043 * @format: (allow-none): the printf-like format to use, or %NULL
2045 * This function is only used internally by the gst_element_error() macro.
2047 * Returns: (transfer full) (nullable): a newly allocated string, or
2048 * %NULL if the format was %NULL or ""
2053 _gst_element_error_printf (const gchar * format, ...)
2064 va_start (args, format);
2066 len = __gst_vasprintf (&buffer, format, args);
2077 * gst_element_message_full_with_details:
2078 * @element: a #GstElement to send message from
2079 * @type: the #GstMessageType
2080 * @domain: the GStreamer GError domain this message belongs to
2081 * @code: the GError code belonging to the domain
2082 * @text: (allow-none) (transfer full): an allocated text string to be used
2083 * as a replacement for the default message connected to code,
2085 * @debug: (allow-none) (transfer full): an allocated debug message to be
2086 * used as a replacement for the default debugging information,
2088 * @file: the source code file where the error was generated
2089 * @function: the source code function where the error was generated
2090 * @line: the source code line where the error was generated
2091 * @structure:(transfer full): optional details structure
2093 * Post an error, warning or info message on the bus from inside an element.
2095 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
2096 * #GST_MESSAGE_INFO.
2100 void gst_element_message_full_with_details
2101 (GstElement * element, GstMessageType type,
2102 GQuark domain, gint code, gchar * text,
2103 gchar * debug, const gchar * file, const gchar * function, gint line,
2104 GstStructure * structure)
2106 GError *gerror = NULL;
2110 gboolean has_debug = TRUE;
2111 GstMessage *message = NULL;
2114 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
2115 g_return_if_fail (GST_IS_ELEMENT (element));
2116 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
2117 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
2119 /* check if we send the given text or the default error text */
2120 if ((text == NULL) || (text[0] == 0)) {
2121 /* text could have come from g_strdup_printf (""); */
2123 sent_text = gst_error_get_message (domain, code);
2127 /* construct a sent_debug with extra information from source */
2128 if ((debug == NULL) || (debug[0] == 0)) {
2129 /* debug could have come from g_strdup_printf (""); */
2133 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
2135 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
2136 file, line, function, name, debug);
2138 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
2139 file, line, function, name);
2143 /* create gerror and post message */
2144 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
2146 gerror = g_error_new_literal (domain, code, sent_text);
2149 case GST_MESSAGE_ERROR:
2151 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
2152 sent_debug, structure);
2154 case GST_MESSAGE_WARNING:
2156 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
2157 gerror, sent_debug, structure);
2159 case GST_MESSAGE_INFO:
2161 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
2162 sent_debug, structure);
2165 g_assert_not_reached ();
2169 gst_element_post_message (element, message);
2171 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
2172 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
2175 g_error_free (gerror);
2176 g_free (sent_debug);
2181 * gst_element_message_full:
2182 * @element: a #GstElement to send message from
2183 * @type: the #GstMessageType
2184 * @domain: the GStreamer GError domain this message belongs to
2185 * @code: the GError code belonging to the domain
2186 * @text: (allow-none) (transfer full): an allocated text string to be used
2187 * as a replacement for the default message connected to code,
2189 * @debug: (allow-none) (transfer full): an allocated debug message to be
2190 * used as a replacement for the default debugging information,
2192 * @file: the source code file where the error was generated
2193 * @function: the source code function where the error was generated
2194 * @line: the source code line where the error was generated
2196 * Post an error, warning or info message on the bus from inside an element.
2198 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
2199 * #GST_MESSAGE_INFO.
2203 void gst_element_message_full
2204 (GstElement * element, GstMessageType type,
2205 GQuark domain, gint code, gchar * text,
2206 gchar * debug, const gchar * file, const gchar * function, gint line)
2208 gst_element_message_full_with_details (element, type, domain, code, text,
2209 debug, file, function, line, NULL);
2213 * gst_element_is_locked_state:
2214 * @element: a #GstElement.
2216 * Checks if the state of an element is locked.
2217 * If the state of an element is locked, state changes of the parent don't
2218 * affect the element.
2219 * This way you can leave currently unused elements inside bins. Just lock their
2220 * state before changing the state from #GST_STATE_NULL.
2224 * Returns: %TRUE, if the element's state is locked.
2227 gst_element_is_locked_state (GstElement * element)
2231 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2233 GST_OBJECT_LOCK (element);
2234 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2235 GST_OBJECT_UNLOCK (element);
2241 * gst_element_set_locked_state:
2242 * @element: a #GstElement
2243 * @locked_state: %TRUE to lock the element's state
2245 * Locks the state of an element, so state changes of the parent don't affect
2246 * this element anymore.
2250 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2251 * or the elements state-locking needed no change.
2254 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2258 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2260 GST_OBJECT_LOCK (element);
2261 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2263 if (G_UNLIKELY (old == locked_state))
2267 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2268 GST_ELEMENT_NAME (element));
2269 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2271 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2272 GST_ELEMENT_NAME (element));
2273 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2275 GST_OBJECT_UNLOCK (element);
2281 GST_CAT_DEBUG (GST_CAT_STATES,
2282 "elements %s was already in locked state %d",
2283 GST_ELEMENT_NAME (element), old);
2284 GST_OBJECT_UNLOCK (element);
2291 * gst_element_sync_state_with_parent:
2292 * @element: a #GstElement.
2294 * Tries to change the state of the element to the same as its parent.
2295 * If this function returns %FALSE, the state of element is undefined.
2297 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2302 gst_element_sync_state_with_parent (GstElement * element)
2306 GstStateChangeReturn ret;
2308 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2310 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2311 GstState parent_current, parent_pending;
2313 GST_OBJECT_LOCK (parent);
2314 parent_current = GST_STATE (parent);
2315 parent_pending = GST_STATE_PENDING (parent);
2316 GST_OBJECT_UNLOCK (parent);
2318 /* set to pending if there is one, else we set it to the current state of
2320 if (parent_pending != GST_STATE_VOID_PENDING)
2321 target = parent_pending;
2323 target = parent_current;
2325 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2326 "syncing state (%s) to parent %s %s (%s, %s)",
2327 gst_element_state_get_name (GST_STATE (element)),
2328 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2329 gst_element_state_get_name (parent_current),
2330 gst_element_state_get_name (parent_pending));
2332 ret = gst_element_set_state (element, target);
2333 if (ret == GST_STATE_CHANGE_FAILURE)
2336 gst_object_unref (parent);
2340 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2347 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2348 "syncing state failed (%s)",
2349 gst_element_state_change_return_get_name (ret));
2350 gst_object_unref (parent);
2356 static GstStateChangeReturn
2357 gst_element_get_state_func (GstElement * element,
2358 GstState * state, GstState * pending, GstClockTime timeout)
2360 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2361 GstState old_pending;
2363 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2364 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2366 GST_OBJECT_LOCK (element);
2367 ret = GST_STATE_RETURN (element);
2368 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2369 gst_element_state_change_return_get_name (ret));
2371 /* we got an error, report immediately */
2372 if (ret == GST_STATE_CHANGE_FAILURE)
2375 /* we got no_preroll, report immediately */
2376 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2379 /* no need to wait async if we are not async */
2380 if (ret != GST_STATE_CHANGE_ASYNC)
2383 old_pending = GST_STATE_PENDING (element);
2384 if (old_pending != GST_STATE_VOID_PENDING) {
2388 /* get cookie to detect state changes during waiting */
2389 cookie = element->state_cookie;
2391 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2392 "waiting for element to commit state");
2394 /* we have a pending state change, wait for it to complete */
2395 if (timeout != GST_CLOCK_TIME_NONE) {
2397 /* make timeout absolute */
2398 end_time = g_get_monotonic_time () + (timeout / 1000);
2399 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2401 GST_STATE_WAIT (element);
2406 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2407 /* timeout triggered */
2408 ret = GST_STATE_CHANGE_ASYNC;
2410 if (cookie != element->state_cookie)
2413 /* could be success or failure */
2414 if (old_pending == GST_STATE (element)) {
2415 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2416 ret = GST_STATE_CHANGE_SUCCESS;
2418 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2419 ret = GST_STATE_CHANGE_FAILURE;
2422 /* if nothing is pending anymore we can return SUCCESS */
2423 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2424 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2425 ret = GST_STATE_CHANGE_SUCCESS;
2431 *state = GST_STATE (element);
2433 *pending = GST_STATE_PENDING (element);
2435 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2436 "state current: %s, pending: %s, result: %s",
2437 gst_element_state_get_name (GST_STATE (element)),
2438 gst_element_state_get_name (GST_STATE_PENDING (element)),
2439 gst_element_state_change_return_get_name (ret));
2440 GST_OBJECT_UNLOCK (element);
2447 *state = GST_STATE_VOID_PENDING;
2449 *pending = GST_STATE_VOID_PENDING;
2451 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2453 GST_OBJECT_UNLOCK (element);
2455 return GST_STATE_CHANGE_FAILURE;
2460 * gst_element_get_state:
2461 * @element: a #GstElement to get the state of.
2462 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2464 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2465 * state. Can be %NULL.
2466 * @timeout: a #GstClockTime to specify the timeout for an async
2467 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2469 * Gets the state of the element.
2471 * For elements that performed an ASYNC state change, as reported by
2472 * gst_element_set_state(), this function will block up to the
2473 * specified timeout value for the state change to complete.
2474 * If the element completes the state change or goes into
2475 * an error, this function returns immediately with a return value of
2476 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2478 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2479 * returns the current and pending state immediately.
2481 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2482 * successfully changed its state but is not able to provide data yet.
2483 * This mostly happens for live sources that only produce data in
2484 * %GST_STATE_PLAYING. While the state change return is equivalent to
2485 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2486 * some sink elements might not be able to complete their state change because
2487 * an element is not producing data to complete the preroll. When setting the
2488 * element to playing, the preroll will complete and playback will start.
2490 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2491 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2492 * element is still performing a state change or
2493 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2497 GstStateChangeReturn
2498 gst_element_get_state (GstElement * element,
2499 GstState * state, GstState * pending, GstClockTime timeout)
2501 GstElementClass *oclass;
2502 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2504 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2506 oclass = GST_ELEMENT_GET_CLASS (element);
2508 if (oclass->get_state)
2509 result = (oclass->get_state) (element, state, pending, timeout);
2515 * gst_element_abort_state:
2516 * @element: a #GstElement to abort the state of.
2518 * Abort the state change of the element. This function is used
2519 * by elements that do asynchronous state changes and find out
2520 * something is wrong.
2522 * This function should be called with the STATE_LOCK held.
2527 gst_element_abort_state (GstElement * element)
2531 #ifndef GST_DISABLE_GST_DEBUG
2535 g_return_if_fail (GST_IS_ELEMENT (element));
2537 GST_OBJECT_LOCK (element);
2538 pending = GST_STATE_PENDING (element);
2540 if (pending == GST_STATE_VOID_PENDING ||
2541 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2542 goto nothing_aborted;
2544 #ifndef GST_DISABLE_GST_DEBUG
2545 old_state = GST_STATE (element);
2547 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2548 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2549 gst_element_state_get_name (pending));
2553 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2555 GST_STATE_BROADCAST (element);
2556 GST_OBJECT_UNLOCK (element);
2562 GST_OBJECT_UNLOCK (element);
2567 /* Not static because GstBin has manual state handling too */
2569 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2570 GstState newstate, GstState pending)
2572 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2573 GstMessage *message;
2575 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2576 "notifying about state-changed %s to %s (%s pending)",
2577 gst_element_state_get_name (oldstate),
2578 gst_element_state_get_name (newstate),
2579 gst_element_state_get_name (pending));
2581 if (klass->state_changed)
2582 klass->state_changed (element, oldstate, newstate, pending);
2584 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2585 oldstate, newstate, pending);
2586 gst_element_post_message (element, message);
2590 * gst_element_continue_state:
2591 * @element: a #GstElement to continue the state change of.
2592 * @ret: The previous state return value
2594 * Commit the state change of the element and proceed to the next
2595 * pending state if any. This function is used
2596 * by elements that do asynchronous state changes.
2597 * The core will normally call this method automatically when an
2598 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2600 * If after calling this method the element still has not reached
2601 * the pending state, the next state change is performed.
2603 * This method is used internally and should normally not be called by plugins
2606 * This function must be called with STATE_LOCK held.
2608 * Returns: The result of the commit state change.
2612 GstStateChangeReturn
2613 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2615 GstStateChangeReturn old_ret;
2616 GstState old_state, old_next;
2617 GstState current, next, pending;
2618 GstStateChange transition;
2620 GST_OBJECT_LOCK (element);
2621 old_ret = GST_STATE_RETURN (element);
2622 GST_STATE_RETURN (element) = ret;
2623 pending = GST_STATE_PENDING (element);
2625 /* check if there is something to commit */
2626 if (pending == GST_STATE_VOID_PENDING)
2627 goto nothing_pending;
2629 old_state = GST_STATE (element);
2630 /* this is the state we should go to next */
2631 old_next = GST_STATE_NEXT (element);
2632 /* update current state */
2633 current = GST_STATE (element) = old_next;
2635 /* see if we reached the final state */
2636 if (pending == current)
2639 next = GST_STATE_GET_NEXT (current, pending);
2640 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2642 GST_STATE_NEXT (element) = next;
2644 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2645 GST_OBJECT_UNLOCK (element);
2647 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2648 "committing state from %s to %s, pending %s, next %s",
2649 gst_element_state_get_name (old_state),
2650 gst_element_state_get_name (old_next),
2651 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2653 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2655 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2656 "continue state change %s to %s, final %s",
2657 gst_element_state_get_name (current),
2658 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2660 ret = gst_element_change_state (element, transition);
2666 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2667 GST_OBJECT_UNLOCK (element);
2672 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2673 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2675 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2676 "completed state change to %s", gst_element_state_get_name (pending));
2677 GST_OBJECT_UNLOCK (element);
2679 /* don't post silly messages with the same state. This can happen
2680 * when an element state is changed to what it already was. For bins
2681 * this can be the result of a lost state, which we check with the
2682 * previous return value.
2683 * We do signal the cond though as a _get_state() might be blocking
2685 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2686 _priv_gst_element_state_changed (element, old_state, old_next,
2687 GST_STATE_VOID_PENDING);
2689 GST_STATE_BROADCAST (element);
2696 * gst_element_lost_state:
2697 * @element: a #GstElement the state is lost of
2699 * Brings the element to the lost state. The current state of the
2700 * element is copied to the pending state so that any call to
2701 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2703 * An ASYNC_START message is posted. If the element was PLAYING, it will
2704 * go to PAUSED. The element will be restored to its PLAYING state by
2705 * the parent pipeline when it prerolls again.
2707 * This is mostly used for elements that lost their preroll buffer
2708 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2709 * they will go to their pending state again when a new preroll buffer is
2710 * queued. This function can only be called when the element is currently
2711 * not in error or an async state change.
2713 * This function is used internally and should normally not be called from
2714 * plugins or applications.
2717 gst_element_lost_state (GstElement * element)
2719 GstState old_state, new_state;
2720 GstMessage *message;
2722 g_return_if_fail (GST_IS_ELEMENT (element));
2724 GST_OBJECT_LOCK (element);
2725 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2728 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2729 goto only_async_start;
2731 old_state = GST_STATE (element);
2733 /* when we were PLAYING, the new state is PAUSED. We will also not
2734 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2735 * when we preroll. */
2736 if (old_state > GST_STATE_PAUSED)
2737 new_state = GST_STATE_PAUSED;
2739 new_state = old_state;
2741 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2742 "lost state of %s to %s", gst_element_state_get_name (old_state),
2743 gst_element_state_get_name (new_state));
2745 GST_STATE (element) = new_state;
2746 GST_STATE_NEXT (element) = new_state;
2747 GST_STATE_PENDING (element) = new_state;
2748 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2749 GST_OBJECT_UNLOCK (element);
2751 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2753 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2754 gst_element_post_message (element, message);
2760 GST_OBJECT_UNLOCK (element);
2765 GST_OBJECT_UNLOCK (element);
2767 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2768 gst_element_post_message (element, message);
2774 * gst_element_set_state:
2775 * @element: a #GstElement to change state of.
2776 * @state: the element's new #GstState.
2778 * Sets the state of the element. This function will try to set the
2779 * requested state by going through all the intermediary states and calling
2780 * the class's state change function for each.
2782 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2783 * element will perform the remainder of the state change asynchronously in
2785 * An application can use gst_element_get_state() to wait for the completion
2786 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2787 * %GST_MESSAGE_STATE_CHANGED on the bus.
2789 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2790 * #GST_STATE_CHANGE_ASYNC.
2792 * Returns: Result of the state change using #GstStateChangeReturn.
2796 GstStateChangeReturn
2797 gst_element_set_state (GstElement * element, GstState state)
2799 GstElementClass *oclass;
2800 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2802 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2804 oclass = GST_ELEMENT_GET_CLASS (element);
2806 if (oclass->set_state)
2807 result = (oclass->set_state) (element, state);
2813 * default set state function, calculates the next state based
2814 * on current state and calls the change_state function
2816 static GstStateChangeReturn
2817 gst_element_set_state_func (GstElement * element, GstState state)
2819 GstState current, next, old_pending;
2820 GstStateChangeReturn ret;
2821 GstStateChange transition;
2822 GstStateChangeReturn old_ret;
2824 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2826 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2827 gst_element_state_get_name (state));
2829 /* state lock is taken to protect the set_state() and get_state()
2830 * procedures, it does not lock any variables. */
2831 GST_STATE_LOCK (element);
2833 /* now calculate how to get to the new state */
2834 GST_OBJECT_LOCK (element);
2835 old_ret = GST_STATE_RETURN (element);
2836 /* previous state change returned an error, remove all pending
2837 * and next states */
2838 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2839 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2840 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2841 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2844 current = GST_STATE (element);
2845 next = GST_STATE_NEXT (element);
2846 old_pending = GST_STATE_PENDING (element);
2848 /* this is the (new) state we should go to. TARGET is the last state we set on
2850 if (state != GST_STATE_TARGET (element)) {
2851 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2852 "setting target state to %s", gst_element_state_get_name (state));
2853 GST_STATE_TARGET (element) = state;
2854 /* increment state cookie so that we can track each state change. We only do
2855 * this if this is actually a new state change. */
2856 element->state_cookie++;
2858 GST_STATE_PENDING (element) = state;
2860 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2861 "current %s, old_pending %s, next %s, old return %s",
2862 gst_element_state_get_name (current),
2863 gst_element_state_get_name (old_pending),
2864 gst_element_state_get_name (next),
2865 gst_element_state_change_return_get_name (old_ret));
2867 /* if the element was busy doing a state change, we just update the
2868 * target state, it'll get to it async then. */
2869 if (old_pending != GST_STATE_VOID_PENDING) {
2870 /* upwards state change will happen ASYNC */
2871 if (old_pending <= state)
2873 /* element is going to this state already */
2874 else if (next == state)
2876 /* element was performing an ASYNC upward state change and
2877 * we request to go downward again. Start from the next pending
2879 else if (next > state
2880 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2884 next = GST_STATE_GET_NEXT (current, state);
2885 /* now we store the next state */
2886 GST_STATE_NEXT (element) = next;
2887 /* mark busy, we need to check that there is actually a state change
2888 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2889 * the default element change_state function has no way to know what the
2890 * old value was... could consider this a FIXME...*/
2891 if (current != next)
2892 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2894 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2896 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2897 "%s: setting state from %s to %s",
2898 (next != state ? "intermediate" : "final"),
2899 gst_element_state_get_name (current), gst_element_state_get_name (next));
2901 /* now signal any waiters, they will error since the cookie was incremented */
2902 GST_STATE_BROADCAST (element);
2904 GST_OBJECT_UNLOCK (element);
2906 ret = gst_element_change_state (element, transition);
2908 GST_STATE_UNLOCK (element);
2910 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2911 gst_element_state_change_return_get_name (ret));
2917 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2918 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2919 "element was busy with async state change");
2920 GST_OBJECT_UNLOCK (element);
2922 GST_STATE_UNLOCK (element);
2924 return GST_STATE_CHANGE_ASYNC;
2929 * gst_element_change_state:
2930 * @element: a #GstElement
2931 * @transition: the requested transition
2933 * Perform @transition on @element.
2935 * This function must be called with STATE_LOCK held and is mainly used
2938 * Returns: the #GstStateChangeReturn of the state transition.
2940 GstStateChangeReturn
2941 gst_element_change_state (GstElement * element, GstStateChange transition)
2943 GstElementClass *oclass;
2944 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2946 oclass = GST_ELEMENT_GET_CLASS (element);
2948 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2950 /* call the state change function so it can set the state */
2951 if (oclass->change_state)
2952 ret = (oclass->change_state) (element, transition);
2954 ret = GST_STATE_CHANGE_FAILURE;
2956 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2959 case GST_STATE_CHANGE_FAILURE:
2960 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2961 "have FAILURE change_state return");
2962 /* state change failure */
2963 gst_element_abort_state (element);
2965 case GST_STATE_CHANGE_ASYNC:
2969 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2970 "element will change state ASYNC");
2972 target = GST_STATE_TARGET (element);
2974 if (target > GST_STATE_READY)
2977 /* else we just continue the state change downwards */
2978 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2979 "forcing commit state %s <= %s",
2980 gst_element_state_get_name (target),
2981 gst_element_state_get_name (GST_STATE_READY));
2983 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2986 case GST_STATE_CHANGE_SUCCESS:
2987 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2988 "element changed state SUCCESS");
2989 /* we can commit the state now which will proceeed to
2991 ret = gst_element_continue_state (element, ret);
2993 case GST_STATE_CHANGE_NO_PREROLL:
2994 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2995 "element changed state NO_PREROLL");
2996 /* we can commit the state now which will proceeed to
2998 ret = gst_element_continue_state (element, ret);
3001 goto invalid_return;
3004 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
3009 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
3017 GST_OBJECT_LOCK (element);
3018 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
3019 g_critical ("%s: unknown return value %d from a state change function",
3020 GST_ELEMENT_NAME (element), ret);
3022 /* we are in error now */
3023 ret = GST_STATE_CHANGE_FAILURE;
3024 GST_STATE_RETURN (element) = ret;
3025 GST_OBJECT_UNLOCK (element);
3031 /* gst_iterator_fold functions for pads_activate
3032 * Stop the iterator if activating one pad failed, but only if that pad
3033 * has not been removed from the element. */
3035 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
3037 GstPad *pad = g_value_get_object (vpad);
3038 gboolean cont = TRUE;
3040 if (!gst_pad_set_active (pad, *active)) {
3041 if (GST_PAD_PARENT (pad) != NULL) {
3043 g_value_set_boolean (ret, FALSE);
3050 /* returns false on error or early cutout of the fold, true if all
3051 * pads in @iter were (de)activated successfully. */
3053 iterator_activate_fold_with_resync (GstIterator * iter,
3054 GstIteratorFoldFunction func, gpointer user_data)
3056 GstIteratorResult ires;
3059 /* no need to unset this later, it's just a boolean */
3060 g_value_init (&ret, G_TYPE_BOOLEAN);
3061 g_value_set_boolean (&ret, TRUE);
3064 ires = gst_iterator_fold (iter, func, &ret, user_data);
3066 case GST_ITERATOR_RESYNC:
3067 /* need to reset the result again */
3068 g_value_set_boolean (&ret, TRUE);
3069 gst_iterator_resync (iter);
3071 case GST_ITERATOR_DONE:
3072 /* all pads iterated, return collected value */
3075 /* iterator returned _ERROR or premature end with _OK,
3076 * mark an error and exit */
3077 g_value_set_boolean (&ret, FALSE);
3082 /* return collected value */
3083 return g_value_get_boolean (&ret);
3086 /* is called with STATE_LOCK
3088 * Pads are activated from source pads to sinkpads.
3091 gst_element_pads_activate (GstElement * element, gboolean active)
3096 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3097 "%s pads", active ? "activate" : "deactivate");
3099 iter = gst_element_iterate_src_pads (element);
3101 iterator_activate_fold_with_resync (iter,
3102 (GstIteratorFoldFunction) activate_pads, &active);
3103 gst_iterator_free (iter);
3104 if (G_UNLIKELY (!res))
3107 iter = gst_element_iterate_sink_pads (element);
3109 iterator_activate_fold_with_resync (iter,
3110 (GstIteratorFoldFunction) activate_pads, &active);
3111 gst_iterator_free (iter);
3112 if (G_UNLIKELY (!res))
3115 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3116 "pad %sactivation successful", active ? "" : "de");
3123 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3124 "pad %sactivation failed", active ? "" : "de");
3129 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3130 "sink pads_activate failed");
3135 /* is called with STATE_LOCK */
3136 static GstStateChangeReturn
3137 gst_element_change_state_func (GstElement * element, GstStateChange transition)
3139 GstState state, next;
3140 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
3142 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
3144 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
3145 next = GST_STATE_TRANSITION_NEXT (transition);
3147 /* if the element already is in the given state, we just return success */
3148 if (next == GST_STATE_VOID_PENDING || state == next)
3151 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
3152 "default handler tries setting state from %s to %s (%04x)",
3153 gst_element_state_get_name (state),
3154 gst_element_state_get_name (next), transition);
3156 switch (transition) {
3157 case GST_STATE_CHANGE_NULL_TO_READY:
3159 case GST_STATE_CHANGE_READY_TO_PAUSED:
3160 if (!gst_element_pads_activate (element, TRUE)) {
3161 result = GST_STATE_CHANGE_FAILURE;
3164 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
3166 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
3168 case GST_STATE_CHANGE_PAUSED_TO_READY:
3169 case GST_STATE_CHANGE_READY_TO_NULL:{
3172 /* deactivate pads in both cases, since they are activated on
3173 ready->paused but the element might not have made it to paused */
3174 if (!gst_element_pads_activate (element, FALSE)) {
3175 result = GST_STATE_CHANGE_FAILURE;
3178 /* Remove all non-persistent contexts */
3179 GST_OBJECT_LOCK (element);
3180 for (l = element->contexts; l;) {
3181 GstContext *context = l->data;
3183 if (!gst_context_is_persistent (context)) {
3186 gst_context_unref (context);
3188 element->contexts = g_list_delete_link (element->contexts, l);
3194 GST_OBJECT_UNLOCK (element);
3198 /* this will catch real but unhandled state changes;
3199 * can only be caused by:
3200 * - a new state was added
3201 * - somehow the element was asked to jump across an intermediate state
3203 g_warning ("Unhandled state change from %s to %s",
3204 gst_element_state_get_name (state),
3205 gst_element_state_get_name (next));
3212 GST_OBJECT_LOCK (element);
3213 result = GST_STATE_RETURN (element);
3214 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3215 "element is already in the %s state",
3216 gst_element_state_get_name (state));
3217 GST_OBJECT_UNLOCK (element);
3224 * gst_element_get_factory:
3225 * @element: a #GstElement to request the element factory of.
3227 * Retrieves the factory that was used to create this element.
3229 * Returns: (transfer none): the #GstElementFactory used for creating this
3230 * element. no refcounting is needed.
3233 gst_element_get_factory (GstElement * element)
3235 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3237 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3241 gst_element_dispose (GObject * object)
3243 GstElement *element = GST_ELEMENT_CAST (object);
3246 GstElementClass *oclass;
3249 oclass = GST_ELEMENT_GET_CLASS (element);
3251 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3253 if (GST_STATE (element) != GST_STATE_NULL)
3256 /* start by releasing all request pads, this might also remove some dynamic
3258 walk = element->pads;
3260 GstPad *pad = GST_PAD_CAST (walk->data);
3264 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3265 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3266 == GST_PAD_REQUEST) {
3267 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3268 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3269 oclass->release_pad (element, pad);
3271 /* in case the release_pad function removed the next pad too */
3272 if (walk && g_list_position (element->pads, walk) == -1)
3273 walk = element->pads;
3276 /* remove the remaining pads */
3277 while (element->pads) {
3278 GstPad *pad = GST_PAD_CAST (element->pads->data);
3279 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3280 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3281 if (!gst_element_remove_pad (element, pad)) {
3282 /* only happens when someone unparented our pad.. */
3283 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3288 GST_OBJECT_LOCK (element);
3289 clock_p = &element->clock;
3290 bus_p = &element->bus;
3291 gst_object_replace ((GstObject **) clock_p, NULL);
3292 gst_object_replace ((GstObject **) bus_p, NULL);
3293 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3294 GST_OBJECT_UNLOCK (element);
3296 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3299 G_OBJECT_CLASS (parent_class)->dispose (object);
3308 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3310 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3312 "You need to explicitly set elements to the NULL state before\n"
3313 "dropping the final reference, to allow them to clean up.\n"
3314 "This problem may also be caused by a refcounting bug in the\n"
3315 "application or some element.\n",
3316 GST_OBJECT_NAME (element),
3317 gst_element_state_get_name (GST_STATE (element)),
3318 is_locked ? " (locked)" : "");
3324 gst_element_finalize (GObject * object)
3326 GstElement *element = GST_ELEMENT_CAST (object);
3328 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3330 g_cond_clear (&element->state_cond);
3331 g_rec_mutex_clear (&element->state_lock);
3333 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3336 G_OBJECT_CLASS (parent_class)->finalize (object);
3340 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3344 g_return_if_fail (GST_IS_ELEMENT (element));
3346 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3348 GST_OBJECT_LOCK (element);
3349 bus_p = &GST_ELEMENT_BUS (element);
3350 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3351 GST_OBJECT_UNLOCK (element);
3355 * gst_element_set_bus:
3356 * @element: a #GstElement to set the bus of.
3357 * @bus: (transfer none): the #GstBus to set.
3359 * Sets the bus of the element. Increases the refcount on the bus.
3360 * For internal use only, unless you're testing elements.
3365 gst_element_set_bus (GstElement * element, GstBus * bus)
3367 GstElementClass *oclass;
3369 g_return_if_fail (GST_IS_ELEMENT (element));
3371 oclass = GST_ELEMENT_GET_CLASS (element);
3373 if (oclass->set_bus)
3374 oclass->set_bus (element, bus);
3378 * gst_element_get_bus:
3379 * @element: a #GstElement to get the bus of.
3381 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3382 * bus for the application.
3384 * Returns: (transfer full): the element's #GstBus. unref after usage.
3389 gst_element_get_bus (GstElement * element)
3391 GstBus *result = NULL;
3393 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3395 GST_OBJECT_LOCK (element);
3396 if ((result = GST_ELEMENT_BUS (element)))
3397 gst_object_ref (result);
3398 GST_OBJECT_UNLOCK (element);
3400 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3407 gst_element_set_context_default (GstElement * element, GstContext * context)
3409 const gchar *context_type;
3412 g_return_if_fail (GST_IS_CONTEXT (context));
3413 context_type = gst_context_get_context_type (context);
3414 g_return_if_fail (context_type != NULL);
3416 GST_OBJECT_LOCK (element);
3417 for (l = element->contexts; l; l = l->next) {
3418 GstContext *tmp = l->data;
3419 const gchar *tmp_type = gst_context_get_context_type (tmp);
3421 /* Always store newest context but never replace
3422 * a persistent one by a non-persistent one */
3423 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3424 (gst_context_is_persistent (context) ||
3425 !gst_context_is_persistent (tmp))) {
3426 gst_context_replace ((GstContext **) & l->data, context);
3430 /* Not found? Add */
3433 g_list_prepend (element->contexts, gst_context_ref (context));
3435 GST_OBJECT_UNLOCK (element);
3439 * gst_element_set_context:
3440 * @element: a #GstElement to set the context of.
3441 * @context: (transfer none): the #GstContext to set.
3443 * Sets the context of the element. Increases the refcount of the context.
3448 gst_element_set_context (GstElement * element, GstContext * context)
3450 GstElementClass *oclass;
3452 g_return_if_fail (GST_IS_ELEMENT (element));
3453 g_return_if_fail (GST_IS_CONTEXT (context));
3455 oclass = GST_ELEMENT_GET_CLASS (element);
3457 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3458 "set context %p %" GST_PTR_FORMAT, context,
3459 gst_context_get_structure (context));
3461 if (oclass->set_context)
3462 oclass->set_context (element, context);
3466 * gst_element_get_contexts:
3467 * @element: a #GstElement to set the context of.
3469 * Gets the contexts set on the element.
3473 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3478 gst_element_get_contexts (GstElement * element)
3482 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3484 GST_OBJECT_LOCK (element);
3485 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3486 GST_OBJECT_UNLOCK (element);
3492 _match_context_type (GstContext * c1, const gchar * context_type)
3494 const gchar *c1_type;
3496 c1_type = gst_context_get_context_type (c1);
3498 return g_strcmp0 (c1_type, context_type);
3502 * gst_element_get_context_unlocked:
3503 * @element: a #GstElement to get the context of.
3504 * @context_type: a name of a context to retrieve
3506 * Gets the context with @context_type set on the element or NULL.
3508 * Returns: (transfer full): A #GstContext or NULL
3513 gst_element_get_context_unlocked (GstElement * element,
3514 const gchar * context_type)
3516 GstContext *ret = NULL;
3519 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3522 g_list_find_custom (element->contexts, context_type,
3523 (GCompareFunc) _match_context_type);
3524 if (node && node->data)
3525 ret = gst_context_ref (node->data);
3531 * gst_element_get_context:
3532 * @element: a #GstElement to get the context of.
3533 * @context_type: a name of a context to retrieve
3535 * Gets the context with @context_type set on the element or NULL.
3539 * Returns: (transfer full): A #GstContext or NULL
3544 gst_element_get_context (GstElement * element, const gchar * context_type)
3546 GstContext *ret = NULL;
3548 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3550 GST_OBJECT_LOCK (element);
3551 ret = gst_element_get_context_unlocked (element, context_type);
3552 GST_OBJECT_UNLOCK (element);
3558 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3559 GParamSpec * pspec, gboolean include_value)
3561 GValue val = G_VALUE_INIT;
3564 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3565 "changed, posting message with%s value", pspec->name, obj,
3566 include_value ? "" : "out");
3568 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3569 g_value_init (&val, pspec->value_type);
3570 g_object_get_property (obj, pspec->name, &val);
3575 gst_element_post_message (element,
3576 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3580 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3581 GParamSpec * pspec, gpointer user_data)
3583 gboolean include_value = GPOINTER_TO_INT (user_data);
3585 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3590 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3593 gboolean include_value = GPOINTER_TO_INT (user_data);
3595 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3600 * gst_element_add_property_notify_watch:
3601 * @element: a #GstElement to watch for property changes
3602 * @property_name: (allow-none): name of property to watch for changes, or
3603 * NULL to watch all properties
3604 * @include_value: whether to include the new property value in the message
3606 * Returns: a watch id, which can be used in connection with
3607 * gst_element_remove_property_notify_watch() to remove the watch again.
3612 gst_element_add_property_notify_watch (GstElement * element,
3613 const gchar * property_name, gboolean include_value)
3619 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3621 sep = (property_name != NULL) ? "::" : NULL;
3622 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3623 id = g_signal_connect (element, signal_name,
3624 G_CALLBACK (gst_element_property_notify_cb),
3625 GINT_TO_POINTER (include_value));
3626 g_free (signal_name);
3632 * gst_element_add_property_deep_notify_watch:
3633 * @element: a #GstElement to watch (recursively) for property changes
3634 * @property_name: (allow-none): name of property to watch for changes, or
3635 * NULL to watch all properties
3636 * @include_value: whether to include the new property value in the message
3638 * Returns: a watch id, which can be used in connection with
3639 * gst_element_remove_property_notify_watch() to remove the watch again.
3644 gst_element_add_property_deep_notify_watch (GstElement * element,
3645 const gchar * property_name, gboolean include_value)
3651 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3653 sep = (property_name != NULL) ? "::" : NULL;
3654 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3655 id = g_signal_connect (element, signal_name,
3656 G_CALLBACK (gst_element_property_deep_notify_cb),
3657 GINT_TO_POINTER (include_value));
3658 g_free (signal_name);
3664 * gst_element_remove_property_notify_watch:
3665 * @element: a #GstElement being watched for property changes
3666 * @watch_id: watch id to remove
3671 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3673 g_signal_handler_disconnect (element, watch_id);
3678 GstElement *element;
3679 GstElementCallAsyncFunc func;
3681 GDestroyNotify destroy_notify;
3682 } GstElementCallAsyncData;
3685 gst_element_call_async_func (gpointer data, gpointer user_data)
3687 GstElementCallAsyncData *async_data = data;
3689 async_data->func (async_data->element, async_data->user_data);
3690 if (async_data->destroy_notify)
3691 async_data->destroy_notify (async_data->user_data);
3692 gst_object_unref (async_data->element);
3693 g_free (async_data);
3697 * gst_element_call_async:
3698 * @element: a #GstElement
3699 * @func: Function to call asynchronously from another thread
3700 * @user_data: Data to pass to @func
3701 * @destroy_notify: GDestroyNotify for @user_data
3703 * Calls @func from another thread and passes @user_data to it. This is to be
3704 * used for cases when a state change has to be performed from a streaming
3705 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3708 * Calling those functions directly from the streaming thread will cause
3709 * deadlocks in many situations, as they might involve waiting for the
3710 * streaming thread to shut down from this very streaming thread.
3717 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3718 gpointer user_data, GDestroyNotify destroy_notify)
3720 GstElementCallAsyncData *async_data;
3722 g_return_if_fail (GST_IS_ELEMENT (element));
3724 async_data = g_new0 (GstElementCallAsyncData, 1);
3725 async_data->element = gst_object_ref (element);
3726 async_data->func = func;
3727 async_data->user_data = user_data;
3728 async_data->destroy_notify = destroy_notify;
3730 g_thread_pool_push (gst_element_pool, async_data, NULL);
3734 _priv_gst_element_cleanup (void)
3736 if (gst_element_pool) {
3737 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3738 gst_element_setup_thread_pool ();
3743 gst_make_element_message_details (const char *name, ...)
3745 GstStructure *structure;
3751 va_start (varargs, name);
3752 structure = gst_structure_new_valist ("details", name, varargs);