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 full): 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);
731 ("Pad %s already has parent when trying to add to element %s",
732 pad_name, GST_ELEMENT_NAME (element));
733 GST_OBJECT_UNLOCK (element);
739 GST_OBJECT_LOCK (pad);
741 ("Trying to add pad %s to element %s, but it has no direction",
742 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
743 GST_OBJECT_UNLOCK (pad);
744 GST_OBJECT_UNLOCK (element);
750 * gst_element_remove_pad:
751 * @element: a #GstElement to remove pad from.
752 * @pad: (transfer full): the #GstPad to remove from the element.
754 * Removes @pad from @element. @pad will be destroyed if it has not been
755 * referenced elsewhere using gst_object_unparent().
757 * This function is used by plugin developers and should not be used
758 * by applications. Pads that were dynamically requested from elements
759 * with gst_element_request_pad() should be released with the
760 * gst_element_release_request_pad() function instead.
762 * Pads are not automatically deactivated so elements should perform the needed
763 * steps to deactivate the pad in case this pad is removed in the PAUSED or
764 * PLAYING state. See gst_pad_set_active() for more information about
767 * The pad and the element should be unlocked when calling this function.
769 * This function will emit the #GstElement::pad-removed signal on the element.
771 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
772 * pad does not belong to the provided element.
777 gst_element_remove_pad (GstElement * element, GstPad * pad)
781 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
782 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
784 /* locking pad to look at the name and parent */
785 GST_OBJECT_LOCK (pad);
786 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
787 GST_STR_NULL (GST_PAD_NAME (pad)));
789 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
791 GST_OBJECT_UNLOCK (pad);
794 if ((peer = gst_pad_get_peer (pad))) {
795 /* window for MT unsafeness, someone else could unlink here
796 * and then we call unlink with wrong pads. The unlink
797 * function would catch this and safely return failed. */
798 if (GST_PAD_IS_SRC (pad))
799 gst_pad_unlink (pad, peer);
801 gst_pad_unlink (peer, pad);
803 gst_object_unref (peer);
806 GST_OBJECT_LOCK (element);
807 /* remove it from the list */
808 switch (gst_pad_get_direction (pad)) {
810 element->srcpads = g_list_remove (element->srcpads, pad);
811 element->numsrcpads--;
814 element->sinkpads = g_list_remove (element->sinkpads, pad);
815 element->numsinkpads--;
818 g_critical ("Removing pad without direction???");
821 element->pads = g_list_remove (element->pads, pad);
823 element->pads_cookie++;
824 GST_OBJECT_UNLOCK (element);
826 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
827 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
828 GST_TRACER_ELEMENT_REMOVE_PAD (element, pad);
829 gst_object_unparent (GST_OBJECT_CAST (pad));
836 /* locking order is element > pad */
837 GST_OBJECT_UNLOCK (pad);
839 GST_OBJECT_LOCK (element);
840 GST_OBJECT_LOCK (pad);
841 g_critical ("Padname %s:%s does not belong to element %s when removing",
842 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
843 GST_OBJECT_UNLOCK (pad);
844 GST_OBJECT_UNLOCK (element);
850 * gst_element_no_more_pads:
851 * @element: a #GstElement
853 * Use this function to signal that the element does not expect any more pads
854 * to show up in the current pipeline. This function should be called whenever
855 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
856 * pad templates use this in combination with autopluggers to figure out that
857 * the element is done initializing its pads.
859 * This function emits the #GstElement::no-more-pads signal.
864 gst_element_no_more_pads (GstElement * element)
866 g_return_if_fail (GST_IS_ELEMENT (element));
868 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
872 pad_compare_name (GstPad * pad1, const gchar * name)
876 GST_OBJECT_LOCK (pad1);
877 result = strcmp (GST_PAD_NAME (pad1), name);
878 GST_OBJECT_UNLOCK (pad1);
884 * gst_element_get_static_pad:
885 * @element: a #GstElement to find a static pad of.
886 * @name: the name of the static #GstPad to retrieve.
888 * Retrieves a pad from @element by name. This version only retrieves
889 * already-existing (i.e. 'static') pads.
891 * Returns: (transfer full) (nullable): the requested #GstPad if
892 * found, otherwise %NULL. unref after usage.
897 gst_element_get_static_pad (GstElement * element, const gchar * name)
900 GstPad *result = NULL;
902 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
903 g_return_val_if_fail (name != NULL, NULL);
905 GST_OBJECT_LOCK (element);
907 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
909 result = GST_PAD_CAST (find->data);
910 gst_object_ref (result);
913 if (result == NULL) {
914 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
915 name, GST_ELEMENT_NAME (element));
917 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
918 GST_ELEMENT_NAME (element), name);
920 GST_OBJECT_UNLOCK (element);
926 gst_element_is_valid_request_template_name (const gchar * templ_name,
930 const gchar *templ_name_ptr, *name_ptr;
931 gboolean next_specifier;
932 guint templ_postfix_len = 0, name_postfix_len = 0;
934 g_return_val_if_fail (templ_name != NULL, FALSE);
935 g_return_val_if_fail (name != NULL, FALSE);
937 /* Is this the template name? */
938 if (strcmp (templ_name, name) == 0)
941 /* otherwise check all the specifiers */
943 /* Because of sanity checks in gst_pad_template_new(), we know that %s
944 * and %d and %u, occurring at the template_name */
945 templ_name_ptr = strchr (templ_name, '%');
947 /* check characters ahead of the specifier */
948 if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
949 || strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
953 /* %s is not allowed for multiple specifiers, just a single specifier can be
954 * accepted in gst_pad_template_new() and can not be mixed with other
955 * specifier '%u' and '%d' */
956 if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
960 name_ptr = name + (templ_name_ptr - templ_name);
962 /* search next specifier, each of specifier should be separated by '_' */
963 templ_name = strchr (templ_name_ptr, '_');
964 name = strchr (name_ptr, '_');
966 /* don't match the number of specifiers */
967 if ((templ_name && !name) || (!templ_name && name))
970 if (templ_name && name)
971 next_specifier = TRUE;
973 next_specifier = FALSE;
975 /* check characters followed by the specifier */
976 if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
977 if (next_specifier) {
978 templ_postfix_len = templ_name - (templ_name_ptr + 2);
979 name_postfix_len = name - name_ptr;
981 templ_postfix_len = strlen (templ_name_ptr + 2);
982 name_postfix_len = strlen (name_ptr);
985 if (strncmp (templ_name_ptr + 2,
986 name_ptr + name_postfix_len - templ_postfix_len,
987 templ_postfix_len) != 0) {
992 /* verify the specifier */
993 if (*(name_ptr) == '%') {
996 len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
998 if (strncmp (name_ptr, templ_name_ptr, len) != 0)
1002 const gchar *specifier;
1003 gchar *target = NULL;
1005 /* extract specifier when it has postfix characters */
1006 if (name_postfix_len > templ_postfix_len) {
1007 target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
1009 specifier = target ? target : name_ptr;
1011 if (*(templ_name_ptr + 1) == 'd') {
1015 tmp = g_ascii_strtoll (specifier, &endptr, 10);
1016 if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
1019 } else if (*(templ_name_ptr + 1) == 'u') {
1023 tmp = g_ascii_strtoull (specifier, &endptr, 10);
1024 if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
1031 /* otherwise we increment these from NULL to 1 */
1032 if (next_specifier) {
1036 } while (next_specifier);
1042 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
1043 const gchar * name, const GstCaps * caps)
1045 GstPad *newpad = NULL;
1046 GstElementClass *oclass;
1048 oclass = GST_ELEMENT_GET_CLASS (element);
1050 #ifndef G_DISABLE_CHECKS
1051 /* Some sanity checking here */
1055 g_return_val_if_fail (gst_element_is_valid_request_template_name
1056 (templ->name_template, name), NULL);
1058 pad = gst_element_get_static_pad (element, name);
1060 gst_object_unref (pad);
1061 /* FIXME 2.0: Change this to g_return_val_if_fail() */
1062 g_critical ("Element %s already has a pad named %s, the behaviour of "
1063 " gst_element_get_request_pad() for existing pads is undefined!",
1064 GST_ELEMENT_NAME (element), name);
1069 if (oclass->request_new_pad)
1070 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1073 gst_object_ref (newpad);
1079 * gst_element_get_request_pad:
1080 * @element: a #GstElement to find a request pad of.
1081 * @name: the name of the request #GstPad to retrieve.
1083 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1084 * retrieves request pads. The pad should be released with
1085 * gst_element_release_request_pad().
1087 * This method is slower than manually getting the pad template and calling
1088 * gst_element_request_pad() if the pads should have a specific name (e.g.
1089 * @name is "src_1" instead of "src_\%u").
1091 * Returns: (transfer full) (nullable): requested #GstPad if found,
1092 * otherwise %NULL. Release after usage.
1095 gst_element_get_request_pad (GstElement * element, const gchar * name)
1097 GstPadTemplate *templ = NULL;
1099 const gchar *req_name = NULL;
1100 gboolean templ_found = FALSE;
1102 GstElementClass *class;
1104 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1105 g_return_val_if_fail (name != NULL, NULL);
1107 class = GST_ELEMENT_GET_CLASS (element);
1109 templ = gst_element_class_get_request_pad_template (class, name);
1111 req_name = strstr (name, "%") ? NULL : name;
1114 /* there is no % in the name, try to find a matching template */
1115 list = class->padtemplates;
1116 while (!templ_found && list) {
1117 templ = (GstPadTemplate *) list->data;
1118 if (templ->presence == GST_PAD_REQUEST) {
1119 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1120 templ->name_template);
1121 if (gst_element_is_valid_request_template_name (templ->name_template,
1135 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1141 * gst_element_request_pad: (virtual request_new_pad)
1142 * @element: a #GstElement to find a request pad of.
1143 * @templ: a #GstPadTemplate of which we want a pad of.
1144 * @name: (transfer none) (allow-none): the name of the request #GstPad
1145 * to retrieve. Can be %NULL.
1146 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1147 * request. Can be %NULL.
1149 * Retrieves a request pad from the element according to the provided template.
1150 * Pad templates can be looked up using
1151 * gst_element_factory_get_static_pad_templates().
1153 * The pad should be released with gst_element_release_request_pad().
1155 * Returns: (transfer full) (nullable): requested #GstPad if found,
1156 * otherwise %NULL. Release after usage.
1159 gst_element_request_pad (GstElement * element,
1160 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1162 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1163 g_return_val_if_fail (templ != NULL, NULL);
1164 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1166 return _gst_element_request_pad (element, templ, name, caps);
1169 static GstIterator *
1170 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1172 GstIterator *result;
1174 GST_OBJECT_LOCK (element);
1175 result = gst_iterator_new_list (GST_TYPE_PAD,
1176 GST_OBJECT_GET_LOCK (element),
1177 &element->pads_cookie, padlist, (GObject *) element, NULL);
1178 GST_OBJECT_UNLOCK (element);
1184 * gst_element_iterate_pads:
1185 * @element: a #GstElement to iterate pads of.
1187 * Retrieves an iterator of @element's pads. The iterator should
1188 * be freed after usage. Also more specialized iterators exists such as
1189 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1191 * The order of pads returned by the iterator will be the order in which
1192 * the pads were added to the element.
1194 * Returns: (transfer full): the #GstIterator of #GstPad.
1199 gst_element_iterate_pads (GstElement * element)
1201 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1203 return gst_element_iterate_pad_list (element, &element->pads);
1207 * gst_element_iterate_src_pads:
1208 * @element: a #GstElement.
1210 * Retrieves an iterator of @element's source pads.
1212 * The order of pads returned by the iterator will be the order in which
1213 * the pads were added to the element.
1215 * Returns: (transfer full): the #GstIterator of #GstPad.
1220 gst_element_iterate_src_pads (GstElement * element)
1222 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1224 return gst_element_iterate_pad_list (element, &element->srcpads);
1228 * gst_element_iterate_sink_pads:
1229 * @element: a #GstElement.
1231 * Retrieves an iterator of @element's sink pads.
1233 * The order of pads returned by the iterator will be the order in which
1234 * the pads were added to the element.
1236 * Returns: (transfer full): the #GstIterator of #GstPad.
1241 gst_element_iterate_sink_pads (GstElement * element)
1243 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1245 return gst_element_iterate_pad_list (element, &element->sinkpads);
1249 * gst_element_class_add_pad_template:
1250 * @klass: the #GstElementClass to add the pad template to.
1251 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1253 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1254 * functions of classes. If a pad template with the same name as an already
1255 * existing one is added the old one is replaced by the new one.
1259 gst_element_class_add_pad_template (GstElementClass * klass,
1260 GstPadTemplate * templ)
1262 GList *template_list = klass->padtemplates;
1264 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1265 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1267 /* If we already have a pad template with the same name replace the
1269 while (template_list) {
1270 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1272 /* Found pad with the same name, replace and return */
1273 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1274 gst_object_unref (padtempl);
1275 template_list->data = templ;
1278 template_list = g_list_next (template_list);
1281 /* Take ownership of the floating ref */
1282 gst_object_ref_sink (templ);
1284 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1285 klass->numpadtemplates++;
1289 * gst_element_class_add_static_pad_template:
1290 * @klass: the #GstElementClass to add the pad template to.
1291 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1293 * Adds a pad template to an element class based on the static pad template
1294 * @templ. This is mainly used in the _class_init functions of element
1295 * implementations. If a pad template with the same name already exists,
1296 * the old one is replaced by the new one.
1301 gst_element_class_add_static_pad_template (GstElementClass * klass,
1302 GstStaticPadTemplate * static_templ)
1304 gst_element_class_add_pad_template (klass,
1305 gst_static_pad_template_get (static_templ));
1309 * gst_element_class_add_metadata:
1310 * @klass: class to set metadata for
1311 * @key: the key to set
1312 * @value: the value to set
1314 * Set @key with @value as metadata in @klass.
1317 gst_element_class_add_metadata (GstElementClass * klass,
1318 const gchar * key, const gchar * value)
1320 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1321 g_return_if_fail (key != NULL);
1322 g_return_if_fail (value != NULL);
1324 gst_structure_set ((GstStructure *) klass->metadata,
1325 key, G_TYPE_STRING, value, NULL);
1329 * gst_element_class_add_static_metadata:
1330 * @klass: class to set metadata for
1331 * @key: the key to set
1332 * @value: the value to set
1334 * Set @key with @value as metadata in @klass.
1336 * Same as gst_element_class_add_metadata(), but @value must be a static string
1337 * or an inlined string, as it will not be copied. (GStreamer plugins will
1338 * be made resident once loaded, so this function can be used even from
1339 * dynamically loaded plugins.)
1342 gst_element_class_add_static_metadata (GstElementClass * klass,
1343 const gchar * key, const gchar * value)
1345 GValue val = G_VALUE_INIT;
1347 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1348 g_return_if_fail (key != NULL);
1349 g_return_if_fail (value != NULL);
1351 g_value_init (&val, G_TYPE_STRING);
1352 g_value_set_static_string (&val, value);
1353 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1357 * gst_element_class_set_metadata:
1358 * @klass: class to set metadata for
1359 * @longname: The long English name of the element. E.g. "File Sink"
1360 * @classification: String describing the type of element, as an unordered list
1361 * separated with slashes ('/'). See draft-klass.txt of the design docs
1362 * for more details and common types. E.g: "Sink/File"
1363 * @description: Sentence describing the purpose of the element.
1364 * E.g: "Write stream to a file"
1365 * @author: Name and contact details of the author(s). Use \n to separate
1366 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1368 * Sets the detailed information for a #GstElementClass.
1369 * > This function is for use in _class_init functions only.
1372 gst_element_class_set_metadata (GstElementClass * klass,
1373 const gchar * longname, const gchar * classification,
1374 const gchar * description, const gchar * author)
1376 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1377 g_return_if_fail (longname != NULL && *longname != '\0');
1378 g_return_if_fail (classification != NULL && *classification != '\0');
1379 g_return_if_fail (description != NULL && *description != '\0');
1380 g_return_if_fail (author != NULL && *author != '\0');
1382 gst_structure_id_set ((GstStructure *) klass->metadata,
1383 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1384 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1385 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1386 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1390 * gst_element_class_set_static_metadata:
1391 * @klass: class to set metadata for
1392 * @longname: The long English name of the element. E.g. "File Sink"
1393 * @classification: String describing the type of element, as an unordered list
1394 * separated with slashes ('/'). See draft-klass.txt of the design docs
1395 * for more details and common types. E.g: "Sink/File"
1396 * @description: Sentence describing the purpose of the element.
1397 * E.g: "Write stream to a file"
1398 * @author: Name and contact details of the author(s). Use \n to separate
1399 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1401 * Sets the detailed information for a #GstElementClass.
1403 * > This function is for use in _class_init functions only.
1405 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1406 * @description, and @author must be static strings or inlined strings, as
1407 * they will not be copied. (GStreamer plugins will be made resident once
1408 * loaded, so this function can be used even from dynamically loaded plugins.)
1411 gst_element_class_set_static_metadata (GstElementClass * klass,
1412 const gchar * longname, const gchar * classification,
1413 const gchar * description, const gchar * author)
1415 GstStructure *s = (GstStructure *) klass->metadata;
1416 GValue val = G_VALUE_INIT;
1418 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1419 g_return_if_fail (longname != NULL && *longname != '\0');
1420 g_return_if_fail (classification != NULL && *classification != '\0');
1421 g_return_if_fail (description != NULL && *description != '\0');
1422 g_return_if_fail (author != NULL && *author != '\0');
1424 g_value_init (&val, G_TYPE_STRING);
1426 g_value_set_static_string (&val, longname);
1427 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1429 g_value_set_static_string (&val, classification);
1430 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1432 g_value_set_static_string (&val, description);
1433 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1436 g_value_set_static_string (&val, author);
1437 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1441 * gst_element_class_get_metadata:
1442 * @klass: class to get metadata for
1443 * @key: the key to get
1445 * Get metadata with @key in @klass.
1447 * Returns: the metadata for @key.
1450 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1452 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1453 g_return_val_if_fail (key != NULL, NULL);
1455 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1459 * gst_element_class_get_pad_template_list:
1460 * @element_class: a #GstElementClass to get pad templates of.
1462 * Retrieves a list of the pad templates associated with @element_class. The
1463 * list must not be modified by the calling code.
1464 * > If you use this function in the #GInstanceInitFunc of an object class
1465 * > that has subclasses, make sure to pass the g_class parameter of the
1466 * > #GInstanceInitFunc here.
1468 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1472 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1474 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1476 return element_class->padtemplates;
1480 * gst_element_class_get_pad_template:
1481 * @element_class: a #GstElementClass to get the pad template of.
1482 * @name: the name of the #GstPadTemplate to get.
1484 * Retrieves a padtemplate from @element_class with the given name.
1485 * > If you use this function in the #GInstanceInitFunc of an object class
1486 * > that has subclasses, make sure to pass the g_class parameter of the
1487 * > #GInstanceInitFunc here.
1489 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1490 * given name, or %NULL if none was found. No unreferencing is
1494 gst_element_class_get_pad_template (GstElementClass *
1495 element_class, const gchar * name)
1499 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1500 g_return_val_if_fail (name != NULL, NULL);
1502 padlist = element_class->padtemplates;
1505 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1507 if (strcmp (padtempl->name_template, name) == 0)
1510 padlist = g_list_next (padlist);
1516 static GstPadTemplate *
1517 gst_element_class_get_request_pad_template (GstElementClass *
1518 element_class, const gchar * name)
1520 GstPadTemplate *tmpl;
1522 tmpl = gst_element_class_get_pad_template (element_class, name);
1523 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1529 /* get a random pad on element of the given direction.
1530 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1533 gst_element_get_random_pad (GstElement * element,
1534 gboolean need_linked, GstPadDirection dir)
1536 GstPad *result = NULL;
1539 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1543 GST_OBJECT_LOCK (element);
1544 pads = element->srcpads;
1547 GST_OBJECT_LOCK (element);
1548 pads = element->sinkpads;
1551 goto wrong_direction;
1553 for (; pads; pads = g_list_next (pads)) {
1554 GstPad *pad = GST_PAD_CAST (pads->data);
1556 GST_OBJECT_LOCK (pad);
1557 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1558 GST_DEBUG_PAD_NAME (pad));
1560 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1561 /* if we require a linked pad, and it is not linked, continue the
1563 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1564 GST_DEBUG_PAD_NAME (pad));
1565 GST_OBJECT_UNLOCK (pad);
1568 /* found a pad, stop search */
1569 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1570 GST_DEBUG_PAD_NAME (pad));
1571 GST_OBJECT_UNLOCK (pad);
1577 gst_object_ref (result);
1579 GST_OBJECT_UNLOCK (element);
1583 /* ERROR handling */
1586 g_warning ("unknown pad direction %d", dir);
1592 gst_element_default_send_event (GstElement * element, GstEvent * event)
1594 gboolean result = FALSE;
1597 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1598 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1599 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1602 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1603 "pushing %s event to random %s pad %s:%s",
1604 GST_EVENT_TYPE_NAME (event),
1605 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1606 GST_DEBUG_PAD_NAME (pad));
1608 result = gst_pad_send_event (pad, event);
1609 gst_object_unref (pad);
1611 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1612 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1613 gst_event_unref (event);
1619 * gst_element_send_event:
1620 * @element: a #GstElement to send the event to.
1621 * @event: (transfer full): the #GstEvent to send to the element.
1623 * Sends an event to an element. If the element doesn't implement an
1624 * event handler, the event will be pushed on a random linked sink pad for
1625 * downstream events or a random linked source pad for upstream events.
1627 * This function takes ownership of the provided event so you should
1628 * gst_event_ref() it if you want to reuse the event after this call.
1632 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1633 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1636 gst_element_send_event (GstElement * element, GstEvent * event)
1638 GstElementClass *oclass;
1639 gboolean result = FALSE;
1641 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1642 g_return_val_if_fail (event != NULL, FALSE);
1644 oclass = GST_ELEMENT_GET_CLASS (element);
1646 GST_STATE_LOCK (element);
1647 if (oclass->send_event) {
1648 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1649 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1650 result = oclass->send_event (element, event);
1652 gst_event_unref (event);
1654 GST_STATE_UNLOCK (element);
1661 * @element: a #GstElement to send the event to.
1662 * @rate: The new playback rate
1663 * @format: The format of the seek values
1664 * @flags: The optional seek flags.
1665 * @start_type: The type and flags for the new start position
1666 * @start: The value of the new start position
1667 * @stop_type: The type and flags for the new stop position
1668 * @stop: The value of the new stop position
1670 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1671 * the parameters. The seek event is sent to the element using
1672 * gst_element_send_event().
1676 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1677 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1680 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1681 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1682 GstSeekType stop_type, gint64 stop)
1687 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1690 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1692 result = gst_element_send_event (element, event);
1698 gst_element_default_query (GstElement * element, GstQuery * query)
1700 gboolean result = FALSE;
1703 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1705 result = gst_pad_query (pad, query);
1707 gst_object_unref (pad);
1709 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1711 GstPad *peer = gst_pad_get_peer (pad);
1714 result = gst_pad_query (peer, query);
1716 gst_object_unref (peer);
1718 gst_object_unref (pad);
1725 * gst_element_query:
1726 * @element: a #GstElement to perform the query on.
1727 * @query: (transfer none): the #GstQuery.
1729 * Performs a query on the given element.
1731 * For elements that don't implement a query handler, this function
1732 * forwards the query to a random srcpad or to the peer of a
1733 * random linked sinkpad of this element.
1735 * Please note that some queries might need a running pipeline to work.
1737 * Returns: %TRUE if the query could be performed.
1742 gst_element_query (GstElement * element, GstQuery * query)
1744 GstElementClass *klass;
1745 gboolean res = FALSE;
1747 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1748 g_return_val_if_fail (query != NULL, FALSE);
1750 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1752 klass = GST_ELEMENT_GET_CLASS (element);
1754 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1755 GST_ELEMENT_NAME (element));
1756 res = klass->query (element, query);
1759 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1764 gst_element_post_message_default (GstElement * element, GstMessage * message)
1767 gboolean result = FALSE;
1769 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1770 g_return_val_if_fail (message != NULL, FALSE);
1772 GST_OBJECT_LOCK (element);
1775 if (G_UNLIKELY (bus == NULL))
1778 gst_object_ref (bus);
1779 GST_OBJECT_UNLOCK (element);
1781 /* we release the element lock when posting the message so that any
1782 * (synchronous) message handlers can operate on the element */
1783 result = gst_bus_post (bus, message);
1784 gst_object_unref (bus);
1791 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1792 "not posting message %p: no bus", message);
1793 GST_OBJECT_UNLOCK (element);
1794 gst_message_unref (message);
1800 * gst_element_post_message:
1801 * @element: a #GstElement posting the message
1802 * @message: (transfer full): a #GstMessage to post
1804 * Post a message on the element's #GstBus. This function takes ownership of the
1805 * message; if you want to access the message after this call, you should add an
1806 * additional reference before calling.
1808 * Returns: %TRUE if the message was successfully posted. The function returns
1809 * %FALSE if the element did not have a bus.
1814 gst_element_post_message (GstElement * element, GstMessage * message)
1816 GstElementClass *klass;
1817 gboolean res = FALSE;
1819 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1820 g_return_val_if_fail (message != NULL, FALSE);
1822 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1824 klass = GST_ELEMENT_GET_CLASS (element);
1825 if (klass->post_message)
1826 res = klass->post_message (element, message);
1828 gst_message_unref (message);
1830 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1835 * _gst_element_error_printf:
1836 * @format: (allow-none): the printf-like format to use, or %NULL
1838 * This function is only used internally by the gst_element_error() macro.
1840 * Returns: (transfer full) (nullable): a newly allocated string, or
1841 * %NULL if the format was %NULL or ""
1846 _gst_element_error_printf (const gchar * format, ...)
1857 va_start (args, format);
1859 len = __gst_vasprintf (&buffer, format, args);
1870 * gst_element_message_full_with_details:
1871 * @element: a #GstElement to send message from
1872 * @type: the #GstMessageType
1873 * @domain: the GStreamer GError domain this message belongs to
1874 * @code: the GError code belonging to the domain
1875 * @text: (allow-none) (transfer full): an allocated text string to be used
1876 * as a replacement for the default message connected to code,
1878 * @debug: (allow-none) (transfer full): an allocated debug message to be
1879 * used as a replacement for the default debugging information,
1881 * @file: the source code file where the error was generated
1882 * @function: the source code function where the error was generated
1883 * @line: the source code line where the error was generated
1884 * @structure:(transfer full): optional details structure
1886 * Post an error, warning or info message on the bus from inside an element.
1888 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1889 * #GST_MESSAGE_INFO.
1893 void gst_element_message_full_with_details
1894 (GstElement * element, GstMessageType type,
1895 GQuark domain, gint code, gchar * text,
1896 gchar * debug, const gchar * file, const gchar * function, gint line,
1897 GstStructure * structure)
1899 GError *gerror = NULL;
1903 gboolean has_debug = TRUE;
1904 GstMessage *message = NULL;
1907 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1908 g_return_if_fail (GST_IS_ELEMENT (element));
1909 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1910 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1912 /* check if we send the given text or the default error text */
1913 if ((text == NULL) || (text[0] == 0)) {
1914 /* text could have come from g_strdup_printf (""); */
1916 sent_text = gst_error_get_message (domain, code);
1920 /* construct a sent_debug with extra information from source */
1921 if ((debug == NULL) || (debug[0] == 0)) {
1922 /* debug could have come from g_strdup_printf (""); */
1926 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1928 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1929 file, line, function, name, debug);
1931 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1932 file, line, function, name);
1936 /* create gerror and post message */
1937 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1939 gerror = g_error_new_literal (domain, code, sent_text);
1942 case GST_MESSAGE_ERROR:
1944 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1945 sent_debug, structure);
1947 case GST_MESSAGE_WARNING:
1949 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1950 gerror, sent_debug, structure);
1952 case GST_MESSAGE_INFO:
1954 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1955 sent_debug, structure);
1958 g_assert_not_reached ();
1962 gst_element_post_message (element, message);
1964 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1965 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1968 g_error_free (gerror);
1969 g_free (sent_debug);
1974 * gst_element_message_full:
1975 * @element: a #GstElement to send message from
1976 * @type: the #GstMessageType
1977 * @domain: the GStreamer GError domain this message belongs to
1978 * @code: the GError code belonging to the domain
1979 * @text: (allow-none) (transfer full): an allocated text string to be used
1980 * as a replacement for the default message connected to code,
1982 * @debug: (allow-none) (transfer full): an allocated debug message to be
1983 * used as a replacement for the default debugging information,
1985 * @file: the source code file where the error was generated
1986 * @function: the source code function where the error was generated
1987 * @line: the source code line where the error was generated
1989 * Post an error, warning or info message on the bus from inside an element.
1991 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1992 * #GST_MESSAGE_INFO.
1996 void gst_element_message_full
1997 (GstElement * element, GstMessageType type,
1998 GQuark domain, gint code, gchar * text,
1999 gchar * debug, const gchar * file, const gchar * function, gint line)
2001 gst_element_message_full_with_details (element, type, domain, code, text,
2002 debug, file, function, line, NULL);
2006 * gst_element_is_locked_state:
2007 * @element: a #GstElement.
2009 * Checks if the state of an element is locked.
2010 * If the state of an element is locked, state changes of the parent don't
2011 * affect the element.
2012 * This way you can leave currently unused elements inside bins. Just lock their
2013 * state before changing the state from #GST_STATE_NULL.
2017 * Returns: %TRUE, if the element's state is locked.
2020 gst_element_is_locked_state (GstElement * element)
2024 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2026 GST_OBJECT_LOCK (element);
2027 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2028 GST_OBJECT_UNLOCK (element);
2034 * gst_element_set_locked_state:
2035 * @element: a #GstElement
2036 * @locked_state: %TRUE to lock the element's state
2038 * Locks the state of an element, so state changes of the parent don't affect
2039 * this element anymore.
2043 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2044 * or the elements state-locking needed no change.
2047 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2051 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2053 GST_OBJECT_LOCK (element);
2054 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2056 if (G_UNLIKELY (old == locked_state))
2060 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2061 GST_ELEMENT_NAME (element));
2062 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2064 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2065 GST_ELEMENT_NAME (element));
2066 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2068 GST_OBJECT_UNLOCK (element);
2074 GST_CAT_DEBUG (GST_CAT_STATES,
2075 "elements %s was already in locked state %d",
2076 GST_ELEMENT_NAME (element), old);
2077 GST_OBJECT_UNLOCK (element);
2084 * gst_element_sync_state_with_parent:
2085 * @element: a #GstElement.
2087 * Tries to change the state of the element to the same as its parent.
2088 * If this function returns %FALSE, the state of element is undefined.
2090 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2095 gst_element_sync_state_with_parent (GstElement * element)
2099 GstStateChangeReturn ret;
2101 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2103 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2104 GstState parent_current, parent_pending;
2106 GST_OBJECT_LOCK (parent);
2107 parent_current = GST_STATE (parent);
2108 parent_pending = GST_STATE_PENDING (parent);
2109 GST_OBJECT_UNLOCK (parent);
2111 /* set to pending if there is one, else we set it to the current state of
2113 if (parent_pending != GST_STATE_VOID_PENDING)
2114 target = parent_pending;
2116 target = parent_current;
2118 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2119 "syncing state (%s) to parent %s %s (%s, %s)",
2120 gst_element_state_get_name (GST_STATE (element)),
2121 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2122 gst_element_state_get_name (parent_current),
2123 gst_element_state_get_name (parent_pending));
2125 ret = gst_element_set_state (element, target);
2126 if (ret == GST_STATE_CHANGE_FAILURE)
2129 gst_object_unref (parent);
2133 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2140 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2141 "syncing state failed (%s)",
2142 gst_element_state_change_return_get_name (ret));
2143 gst_object_unref (parent);
2149 static GstStateChangeReturn
2150 gst_element_get_state_func (GstElement * element,
2151 GstState * state, GstState * pending, GstClockTime timeout)
2153 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2154 GstState old_pending;
2156 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2157 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2159 GST_OBJECT_LOCK (element);
2160 ret = GST_STATE_RETURN (element);
2161 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2162 gst_element_state_change_return_get_name (ret));
2164 /* we got an error, report immediately */
2165 if (ret == GST_STATE_CHANGE_FAILURE)
2168 /* we got no_preroll, report immediately */
2169 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2172 /* no need to wait async if we are not async */
2173 if (ret != GST_STATE_CHANGE_ASYNC)
2176 old_pending = GST_STATE_PENDING (element);
2177 if (old_pending != GST_STATE_VOID_PENDING) {
2181 /* get cookie to detect state changes during waiting */
2182 cookie = element->state_cookie;
2184 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2185 "waiting for element to commit state");
2187 /* we have a pending state change, wait for it to complete */
2188 if (timeout != GST_CLOCK_TIME_NONE) {
2190 /* make timeout absolute */
2191 end_time = g_get_monotonic_time () + (timeout / 1000);
2192 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2194 GST_STATE_WAIT (element);
2199 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2200 /* timeout triggered */
2201 ret = GST_STATE_CHANGE_ASYNC;
2203 if (cookie != element->state_cookie)
2206 /* could be success or failure */
2207 if (old_pending == GST_STATE (element)) {
2208 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2209 ret = GST_STATE_CHANGE_SUCCESS;
2211 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2212 ret = GST_STATE_CHANGE_FAILURE;
2215 /* if nothing is pending anymore we can return SUCCESS */
2216 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2217 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2218 ret = GST_STATE_CHANGE_SUCCESS;
2224 *state = GST_STATE (element);
2226 *pending = GST_STATE_PENDING (element);
2228 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2229 "state current: %s, pending: %s, result: %s",
2230 gst_element_state_get_name (GST_STATE (element)),
2231 gst_element_state_get_name (GST_STATE_PENDING (element)),
2232 gst_element_state_change_return_get_name (ret));
2233 GST_OBJECT_UNLOCK (element);
2240 *state = GST_STATE_VOID_PENDING;
2242 *pending = GST_STATE_VOID_PENDING;
2244 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2246 GST_OBJECT_UNLOCK (element);
2248 return GST_STATE_CHANGE_FAILURE;
2253 * gst_element_get_state:
2254 * @element: a #GstElement to get the state of.
2255 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2257 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2258 * state. Can be %NULL.
2259 * @timeout: a #GstClockTime to specify the timeout for an async
2260 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2262 * Gets the state of the element.
2264 * For elements that performed an ASYNC state change, as reported by
2265 * gst_element_set_state(), this function will block up to the
2266 * specified timeout value for the state change to complete.
2267 * If the element completes the state change or goes into
2268 * an error, this function returns immediately with a return value of
2269 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2271 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2272 * returns the current and pending state immediately.
2274 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2275 * successfully changed its state but is not able to provide data yet.
2276 * This mostly happens for live sources that only produce data in
2277 * %GST_STATE_PLAYING. While the state change return is equivalent to
2278 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2279 * some sink elements might not be able to complete their state change because
2280 * an element is not producing data to complete the preroll. When setting the
2281 * element to playing, the preroll will complete and playback will start.
2283 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2284 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2285 * element is still performing a state change or
2286 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2290 GstStateChangeReturn
2291 gst_element_get_state (GstElement * element,
2292 GstState * state, GstState * pending, GstClockTime timeout)
2294 GstElementClass *oclass;
2295 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2297 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2299 oclass = GST_ELEMENT_GET_CLASS (element);
2301 if (oclass->get_state)
2302 result = (oclass->get_state) (element, state, pending, timeout);
2308 * gst_element_abort_state:
2309 * @element: a #GstElement to abort the state of.
2311 * Abort the state change of the element. This function is used
2312 * by elements that do asynchronous state changes and find out
2313 * something is wrong.
2315 * This function should be called with the STATE_LOCK held.
2320 gst_element_abort_state (GstElement * element)
2324 #ifndef GST_DISABLE_GST_DEBUG
2328 g_return_if_fail (GST_IS_ELEMENT (element));
2330 GST_OBJECT_LOCK (element);
2331 pending = GST_STATE_PENDING (element);
2333 if (pending == GST_STATE_VOID_PENDING ||
2334 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2335 goto nothing_aborted;
2337 #ifndef GST_DISABLE_GST_DEBUG
2338 old_state = GST_STATE (element);
2340 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2341 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2342 gst_element_state_get_name (pending));
2346 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2348 GST_STATE_BROADCAST (element);
2349 GST_OBJECT_UNLOCK (element);
2355 GST_OBJECT_UNLOCK (element);
2360 /* Not static because GstBin has manual state handling too */
2362 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2363 GstState newstate, GstState pending)
2365 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2366 GstMessage *message;
2368 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2369 "notifying about state-changed %s to %s (%s pending)",
2370 gst_element_state_get_name (oldstate),
2371 gst_element_state_get_name (newstate),
2372 gst_element_state_get_name (pending));
2374 if (klass->state_changed)
2375 klass->state_changed (element, oldstate, newstate, pending);
2377 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2378 oldstate, newstate, pending);
2379 gst_element_post_message (element, message);
2383 * gst_element_continue_state:
2384 * @element: a #GstElement to continue the state change of.
2385 * @ret: The previous state return value
2387 * Commit the state change of the element and proceed to the next
2388 * pending state if any. This function is used
2389 * by elements that do asynchronous state changes.
2390 * The core will normally call this method automatically when an
2391 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2393 * If after calling this method the element still has not reached
2394 * the pending state, the next state change is performed.
2396 * This method is used internally and should normally not be called by plugins
2399 * Returns: The result of the commit state change.
2403 GstStateChangeReturn
2404 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2406 GstStateChangeReturn old_ret;
2407 GstState old_state, old_next;
2408 GstState current, next, pending;
2409 GstStateChange transition;
2411 GST_OBJECT_LOCK (element);
2412 old_ret = GST_STATE_RETURN (element);
2413 GST_STATE_RETURN (element) = ret;
2414 pending = GST_STATE_PENDING (element);
2416 /* check if there is something to commit */
2417 if (pending == GST_STATE_VOID_PENDING)
2418 goto nothing_pending;
2420 old_state = GST_STATE (element);
2421 /* this is the state we should go to next */
2422 old_next = GST_STATE_NEXT (element);
2423 /* update current state */
2424 current = GST_STATE (element) = old_next;
2426 /* see if we reached the final state */
2427 if (pending == current)
2430 next = GST_STATE_GET_NEXT (current, pending);
2431 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2433 GST_STATE_NEXT (element) = next;
2435 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2436 GST_OBJECT_UNLOCK (element);
2438 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2439 "committing state from %s to %s, pending %s, next %s",
2440 gst_element_state_get_name (old_state),
2441 gst_element_state_get_name (old_next),
2442 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2444 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2446 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2447 "continue state change %s to %s, final %s",
2448 gst_element_state_get_name (current),
2449 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2451 ret = gst_element_change_state (element, transition);
2457 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2458 GST_OBJECT_UNLOCK (element);
2463 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2464 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2466 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2467 "completed state change to %s", gst_element_state_get_name (pending));
2468 GST_OBJECT_UNLOCK (element);
2470 /* don't post silly messages with the same state. This can happen
2471 * when an element state is changed to what it already was. For bins
2472 * this can be the result of a lost state, which we check with the
2473 * previous return value.
2474 * We do signal the cond though as a _get_state() might be blocking
2476 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2477 _priv_gst_element_state_changed (element, old_state, old_next,
2478 GST_STATE_VOID_PENDING);
2480 GST_STATE_BROADCAST (element);
2487 * gst_element_lost_state:
2488 * @element: a #GstElement the state is lost of
2490 * Brings the element to the lost state. The current state of the
2491 * element is copied to the pending state so that any call to
2492 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2494 * An ASYNC_START message is posted. If the element was PLAYING, it will
2495 * go to PAUSED. The element will be restored to its PLAYING state by
2496 * the parent pipeline when it prerolls again.
2498 * This is mostly used for elements that lost their preroll buffer
2499 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2500 * they will go to their pending state again when a new preroll buffer is
2501 * queued. This function can only be called when the element is currently
2502 * not in error or an async state change.
2504 * This function is used internally and should normally not be called from
2505 * plugins or applications.
2508 gst_element_lost_state (GstElement * element)
2510 GstState old_state, new_state;
2511 GstMessage *message;
2513 g_return_if_fail (GST_IS_ELEMENT (element));
2515 GST_OBJECT_LOCK (element);
2516 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2519 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2520 goto only_async_start;
2522 old_state = GST_STATE (element);
2524 /* when we were PLAYING, the new state is PAUSED. We will also not
2525 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2526 * when we preroll. */
2527 if (old_state > GST_STATE_PAUSED)
2528 new_state = GST_STATE_PAUSED;
2530 new_state = old_state;
2532 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2533 "lost state of %s to %s", gst_element_state_get_name (old_state),
2534 gst_element_state_get_name (new_state));
2536 GST_STATE (element) = new_state;
2537 GST_STATE_NEXT (element) = new_state;
2538 GST_STATE_PENDING (element) = new_state;
2539 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2540 GST_OBJECT_UNLOCK (element);
2542 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2544 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2545 gst_element_post_message (element, message);
2551 GST_OBJECT_UNLOCK (element);
2556 GST_OBJECT_UNLOCK (element);
2558 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2559 gst_element_post_message (element, message);
2565 * gst_element_set_state:
2566 * @element: a #GstElement to change state of.
2567 * @state: the element's new #GstState.
2569 * Sets the state of the element. This function will try to set the
2570 * requested state by going through all the intermediary states and calling
2571 * the class's state change function for each.
2573 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2574 * element will perform the remainder of the state change asynchronously in
2576 * An application can use gst_element_get_state() to wait for the completion
2577 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2578 * %GST_MESSAGE_STATE_CHANGED on the bus.
2580 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2581 * #GST_STATE_CHANGE_ASYNC.
2583 * Returns: Result of the state change using #GstStateChangeReturn.
2587 GstStateChangeReturn
2588 gst_element_set_state (GstElement * element, GstState state)
2590 GstElementClass *oclass;
2591 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2593 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2595 oclass = GST_ELEMENT_GET_CLASS (element);
2597 if (oclass->set_state)
2598 result = (oclass->set_state) (element, state);
2604 * default set state function, calculates the next state based
2605 * on current state and calls the change_state function
2607 static GstStateChangeReturn
2608 gst_element_set_state_func (GstElement * element, GstState state)
2610 GstState current, next, old_pending;
2611 GstStateChangeReturn ret;
2612 GstStateChange transition;
2613 GstStateChangeReturn old_ret;
2615 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2617 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2618 gst_element_state_get_name (state));
2620 /* state lock is taken to protect the set_state() and get_state()
2621 * procedures, it does not lock any variables. */
2622 GST_STATE_LOCK (element);
2624 /* now calculate how to get to the new state */
2625 GST_OBJECT_LOCK (element);
2626 old_ret = GST_STATE_RETURN (element);
2627 /* previous state change returned an error, remove all pending
2628 * and next states */
2629 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2630 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2631 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2632 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2635 current = GST_STATE (element);
2636 next = GST_STATE_NEXT (element);
2637 old_pending = GST_STATE_PENDING (element);
2639 /* this is the (new) state we should go to. TARGET is the last state we set on
2641 if (state != GST_STATE_TARGET (element)) {
2642 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2643 "setting target state to %s", gst_element_state_get_name (state));
2644 GST_STATE_TARGET (element) = state;
2645 /* increment state cookie so that we can track each state change. We only do
2646 * this if this is actually a new state change. */
2647 element->state_cookie++;
2649 GST_STATE_PENDING (element) = state;
2651 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2652 "current %s, old_pending %s, next %s, old return %s",
2653 gst_element_state_get_name (current),
2654 gst_element_state_get_name (old_pending),
2655 gst_element_state_get_name (next),
2656 gst_element_state_change_return_get_name (old_ret));
2658 /* if the element was busy doing a state change, we just update the
2659 * target state, it'll get to it async then. */
2660 if (old_pending != GST_STATE_VOID_PENDING) {
2661 /* upwards state change will happen ASYNC */
2662 if (old_pending <= state)
2664 /* element is going to this state already */
2665 else if (next == state)
2667 /* element was performing an ASYNC upward state change and
2668 * we request to go downward again. Start from the next pending
2670 else if (next > state
2671 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2675 next = GST_STATE_GET_NEXT (current, state);
2676 /* now we store the next state */
2677 GST_STATE_NEXT (element) = next;
2678 /* mark busy, we need to check that there is actually a state change
2679 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2680 * the default element change_state function has no way to know what the
2681 * old value was... could consider this a FIXME...*/
2682 if (current != next)
2683 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2685 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2687 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2688 "%s: setting state from %s to %s",
2689 (next != state ? "intermediate" : "final"),
2690 gst_element_state_get_name (current), gst_element_state_get_name (next));
2692 /* now signal any waiters, they will error since the cookie was incremented */
2693 GST_STATE_BROADCAST (element);
2695 GST_OBJECT_UNLOCK (element);
2697 ret = gst_element_change_state (element, transition);
2699 GST_STATE_UNLOCK (element);
2701 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2702 gst_element_state_change_return_get_name (ret));
2708 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2709 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2710 "element was busy with async state change");
2711 GST_OBJECT_UNLOCK (element);
2713 GST_STATE_UNLOCK (element);
2715 return GST_STATE_CHANGE_ASYNC;
2720 * gst_element_change_state:
2721 * @element: a #GstElement
2722 * @transition: the requested transition
2724 * Perform @transition on @element.
2726 * This function must be called with STATE_LOCK held and is mainly used
2729 * Returns: the #GstStateChangeReturn of the state transition.
2731 GstStateChangeReturn
2732 gst_element_change_state (GstElement * element, GstStateChange transition)
2734 GstElementClass *oclass;
2735 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2737 oclass = GST_ELEMENT_GET_CLASS (element);
2739 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2741 /* call the state change function so it can set the state */
2742 if (oclass->change_state)
2743 ret = (oclass->change_state) (element, transition);
2745 ret = GST_STATE_CHANGE_FAILURE;
2747 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2750 case GST_STATE_CHANGE_FAILURE:
2751 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2752 "have FAILURE change_state return");
2753 /* state change failure */
2754 gst_element_abort_state (element);
2756 case GST_STATE_CHANGE_ASYNC:
2760 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2761 "element will change state ASYNC");
2763 target = GST_STATE_TARGET (element);
2765 if (target > GST_STATE_READY)
2768 /* else we just continue the state change downwards */
2769 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2770 "forcing commit state %s <= %s",
2771 gst_element_state_get_name (target),
2772 gst_element_state_get_name (GST_STATE_READY));
2774 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2777 case GST_STATE_CHANGE_SUCCESS:
2778 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2779 "element changed state SUCCESS");
2780 /* we can commit the state now which will proceeed to
2782 ret = gst_element_continue_state (element, ret);
2784 case GST_STATE_CHANGE_NO_PREROLL:
2785 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2786 "element changed state NO_PREROLL");
2787 /* we can commit the state now which will proceeed to
2789 ret = gst_element_continue_state (element, ret);
2792 goto invalid_return;
2795 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2800 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2808 GST_OBJECT_LOCK (element);
2809 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2810 g_critical ("%s: unknown return value %d from a state change function",
2811 GST_ELEMENT_NAME (element), ret);
2813 /* we are in error now */
2814 ret = GST_STATE_CHANGE_FAILURE;
2815 GST_STATE_RETURN (element) = ret;
2816 GST_OBJECT_UNLOCK (element);
2822 /* gst_iterator_fold functions for pads_activate
2823 * Stop the iterator if activating one pad failed, but only if that pad
2824 * has not been removed from the element. */
2826 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2828 GstPad *pad = g_value_get_object (vpad);
2829 gboolean cont = TRUE;
2831 if (!gst_pad_set_active (pad, *active)) {
2832 if (GST_PAD_PARENT (pad) != NULL) {
2834 g_value_set_boolean (ret, FALSE);
2841 /* returns false on error or early cutout of the fold, true if all
2842 * pads in @iter were (de)activated successfully. */
2844 iterator_activate_fold_with_resync (GstIterator * iter,
2845 GstIteratorFoldFunction func, gpointer user_data)
2847 GstIteratorResult ires;
2850 /* no need to unset this later, it's just a boolean */
2851 g_value_init (&ret, G_TYPE_BOOLEAN);
2852 g_value_set_boolean (&ret, TRUE);
2855 ires = gst_iterator_fold (iter, func, &ret, user_data);
2857 case GST_ITERATOR_RESYNC:
2858 /* need to reset the result again */
2859 g_value_set_boolean (&ret, TRUE);
2860 gst_iterator_resync (iter);
2862 case GST_ITERATOR_DONE:
2863 /* all pads iterated, return collected value */
2866 /* iterator returned _ERROR or premature end with _OK,
2867 * mark an error and exit */
2868 g_value_set_boolean (&ret, FALSE);
2873 /* return collected value */
2874 return g_value_get_boolean (&ret);
2877 /* is called with STATE_LOCK
2879 * Pads are activated from source pads to sinkpads.
2882 gst_element_pads_activate (GstElement * element, gboolean active)
2887 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2888 "%s pads", active ? "activate" : "deactivate");
2890 iter = gst_element_iterate_src_pads (element);
2892 iterator_activate_fold_with_resync (iter,
2893 (GstIteratorFoldFunction) activate_pads, &active);
2894 gst_iterator_free (iter);
2895 if (G_UNLIKELY (!res))
2898 iter = gst_element_iterate_sink_pads (element);
2900 iterator_activate_fold_with_resync (iter,
2901 (GstIteratorFoldFunction) activate_pads, &active);
2902 gst_iterator_free (iter);
2903 if (G_UNLIKELY (!res))
2906 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2907 "pad %sactivation successful", active ? "" : "de");
2914 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2915 "pad %sactivation failed", active ? "" : "de");
2920 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2921 "sink pads_activate failed");
2926 /* is called with STATE_LOCK */
2927 static GstStateChangeReturn
2928 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2930 GstState state, next;
2931 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2933 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2935 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2936 next = GST_STATE_TRANSITION_NEXT (transition);
2938 /* if the element already is in the given state, we just return success */
2939 if (next == GST_STATE_VOID_PENDING || state == next)
2942 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2943 "default handler tries setting state from %s to %s (%04x)",
2944 gst_element_state_get_name (state),
2945 gst_element_state_get_name (next), transition);
2947 switch (transition) {
2948 case GST_STATE_CHANGE_NULL_TO_READY:
2950 case GST_STATE_CHANGE_READY_TO_PAUSED:
2951 if (!gst_element_pads_activate (element, TRUE)) {
2952 result = GST_STATE_CHANGE_FAILURE;
2955 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2957 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2959 case GST_STATE_CHANGE_PAUSED_TO_READY:
2960 case GST_STATE_CHANGE_READY_TO_NULL:{
2963 /* deactivate pads in both cases, since they are activated on
2964 ready->paused but the element might not have made it to paused */
2965 if (!gst_element_pads_activate (element, FALSE)) {
2966 result = GST_STATE_CHANGE_FAILURE;
2969 /* Remove all non-persistent contexts */
2970 GST_OBJECT_LOCK (element);
2971 for (l = element->contexts; l;) {
2972 GstContext *context = l->data;
2974 if (!gst_context_is_persistent (context)) {
2977 gst_context_unref (context);
2979 element->contexts = g_list_delete_link (element->contexts, l);
2985 GST_OBJECT_UNLOCK (element);
2989 /* this will catch real but unhandled state changes;
2990 * can only be caused by:
2991 * - a new state was added
2992 * - somehow the element was asked to jump across an intermediate state
2994 g_warning ("Unhandled state change from %s to %s",
2995 gst_element_state_get_name (state),
2996 gst_element_state_get_name (next));
3003 GST_OBJECT_LOCK (element);
3004 result = GST_STATE_RETURN (element);
3005 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3006 "element is already in the %s state",
3007 gst_element_state_get_name (state));
3008 GST_OBJECT_UNLOCK (element);
3015 * gst_element_get_factory:
3016 * @element: a #GstElement to request the element factory of.
3018 * Retrieves the factory that was used to create this element.
3020 * Returns: (transfer none): the #GstElementFactory used for creating this
3021 * element. no refcounting is needed.
3024 gst_element_get_factory (GstElement * element)
3026 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3028 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3032 gst_element_dispose (GObject * object)
3034 GstElement *element = GST_ELEMENT_CAST (object);
3037 GstElementClass *oclass;
3040 oclass = GST_ELEMENT_GET_CLASS (element);
3042 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3044 if (GST_STATE (element) != GST_STATE_NULL)
3047 /* start by releasing all request pads, this might also remove some dynamic
3049 walk = element->pads;
3051 GstPad *pad = GST_PAD_CAST (walk->data);
3055 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3056 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3057 == GST_PAD_REQUEST) {
3058 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3059 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3060 oclass->release_pad (element, pad);
3062 /* in case the release_pad function removed the next pad too */
3063 if (walk && g_list_position (element->pads, walk) == -1)
3064 walk = element->pads;
3067 /* remove the remaining pads */
3068 while (element->pads) {
3069 GstPad *pad = GST_PAD_CAST (element->pads->data);
3070 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3071 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3072 if (!gst_element_remove_pad (element, pad)) {
3073 /* only happens when someone unparented our pad.. */
3074 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3079 GST_OBJECT_LOCK (element);
3080 clock_p = &element->clock;
3081 bus_p = &element->bus;
3082 gst_object_replace ((GstObject **) clock_p, NULL);
3083 gst_object_replace ((GstObject **) bus_p, NULL);
3084 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3085 GST_OBJECT_UNLOCK (element);
3087 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3090 G_OBJECT_CLASS (parent_class)->dispose (object);
3099 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3101 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3103 "You need to explicitly set elements to the NULL state before\n"
3104 "dropping the final reference, to allow them to clean up.\n"
3105 "This problem may also be caused by a refcounting bug in the\n"
3106 "application or some element.\n",
3107 GST_OBJECT_NAME (element),
3108 gst_element_state_get_name (GST_STATE (element)),
3109 is_locked ? " (locked)" : "");
3115 gst_element_finalize (GObject * object)
3117 GstElement *element = GST_ELEMENT_CAST (object);
3119 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3121 g_cond_clear (&element->state_cond);
3122 g_rec_mutex_clear (&element->state_lock);
3124 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3127 G_OBJECT_CLASS (parent_class)->finalize (object);
3131 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3135 g_return_if_fail (GST_IS_ELEMENT (element));
3137 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3139 GST_OBJECT_LOCK (element);
3140 bus_p = &GST_ELEMENT_BUS (element);
3141 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3142 GST_OBJECT_UNLOCK (element);
3146 * gst_element_set_bus:
3147 * @element: a #GstElement to set the bus of.
3148 * @bus: (transfer none): the #GstBus to set.
3150 * Sets the bus of the element. Increases the refcount on the bus.
3151 * For internal use only, unless you're testing elements.
3156 gst_element_set_bus (GstElement * element, GstBus * bus)
3158 GstElementClass *oclass;
3160 g_return_if_fail (GST_IS_ELEMENT (element));
3162 oclass = GST_ELEMENT_GET_CLASS (element);
3164 if (oclass->set_bus)
3165 oclass->set_bus (element, bus);
3169 * gst_element_get_bus:
3170 * @element: a #GstElement to get the bus of.
3172 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3173 * bus for the application.
3175 * Returns: (transfer full): the element's #GstBus. unref after usage.
3180 gst_element_get_bus (GstElement * element)
3182 GstBus *result = NULL;
3184 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3186 GST_OBJECT_LOCK (element);
3187 if ((result = GST_ELEMENT_BUS (element)))
3188 gst_object_ref (result);
3189 GST_OBJECT_UNLOCK (element);
3191 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3198 gst_element_set_context_default (GstElement * element, GstContext * context)
3200 const gchar *context_type;
3203 g_return_if_fail (GST_IS_CONTEXT (context));
3204 context_type = gst_context_get_context_type (context);
3205 g_return_if_fail (context_type != NULL);
3207 GST_OBJECT_LOCK (element);
3208 for (l = element->contexts; l; l = l->next) {
3209 GstContext *tmp = l->data;
3210 const gchar *tmp_type = gst_context_get_context_type (tmp);
3212 /* Always store newest context but never replace
3213 * a persistent one by a non-persistent one */
3214 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3215 (gst_context_is_persistent (context) ||
3216 !gst_context_is_persistent (tmp))) {
3217 gst_context_replace ((GstContext **) & l->data, context);
3221 /* Not found? Add */
3224 g_list_prepend (element->contexts, gst_context_ref (context));
3226 GST_OBJECT_UNLOCK (element);
3230 * gst_element_set_context:
3231 * @element: a #GstElement to set the context of.
3232 * @context: (transfer none): the #GstContext to set.
3234 * Sets the context of the element. Increases the refcount of the context.
3239 gst_element_set_context (GstElement * element, GstContext * context)
3241 GstElementClass *oclass;
3243 g_return_if_fail (GST_IS_ELEMENT (element));
3244 g_return_if_fail (GST_IS_CONTEXT (context));
3246 oclass = GST_ELEMENT_GET_CLASS (element);
3248 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3249 "set context %p %" GST_PTR_FORMAT, context,
3250 gst_context_get_structure (context));
3252 if (oclass->set_context)
3253 oclass->set_context (element, context);
3257 * gst_element_get_contexts:
3258 * @element: a #GstElement to set the context of.
3260 * Gets the contexts set on the element.
3264 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3269 gst_element_get_contexts (GstElement * element)
3273 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3275 GST_OBJECT_LOCK (element);
3276 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3277 GST_OBJECT_UNLOCK (element);
3283 _match_context_type (GstContext * c1, const gchar * context_type)
3285 const gchar *c1_type;
3287 c1_type = gst_context_get_context_type (c1);
3289 return g_strcmp0 (c1_type, context_type);
3293 * gst_element_get_context_unlocked:
3294 * @element: a #GstElement to get the context of.
3295 * @context_type: a name of a context to retrieve
3297 * Gets the context with @context_type set on the element or NULL.
3299 * Returns: (transfer full): A #GstContext or NULL
3304 gst_element_get_context_unlocked (GstElement * element,
3305 const gchar * context_type)
3307 GstContext *ret = NULL;
3310 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3313 g_list_find_custom (element->contexts, context_type,
3314 (GCompareFunc) _match_context_type);
3315 if (node && node->data)
3316 ret = gst_context_ref (node->data);
3322 * gst_element_get_context:
3323 * @element: a #GstElement to get the context of.
3324 * @context_type: a name of a context to retrieve
3326 * Gets the context with @context_type set on the element or NULL.
3330 * Returns: (transfer full): A #GstContext or NULL
3335 gst_element_get_context (GstElement * element, const gchar * context_type)
3337 GstContext *ret = NULL;
3339 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3341 GST_OBJECT_LOCK (element);
3342 ret = gst_element_get_context_unlocked (element, context_type);
3343 GST_OBJECT_UNLOCK (element);
3349 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3350 GParamSpec * pspec, gboolean include_value)
3352 GValue val = G_VALUE_INIT;
3355 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3356 "changed, posting message with%s value", pspec->name, obj,
3357 include_value ? "" : "out");
3359 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3360 g_value_init (&val, pspec->value_type);
3361 g_object_get_property (obj, pspec->name, &val);
3366 gst_element_post_message (element,
3367 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3371 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3372 GParamSpec * pspec, gpointer user_data)
3374 gboolean include_value = GPOINTER_TO_INT (user_data);
3376 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3381 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3384 gboolean include_value = GPOINTER_TO_INT (user_data);
3386 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3391 * gst_element_add_property_notify_watch:
3392 * @element: a #GstElement to watch for property changes
3393 * @property_name: (allow-none): name of property to watch for changes, or
3394 * NULL to watch all properties
3395 * @include_value: whether to include the new property value in the message
3397 * Returns: a watch id, which can be used in connection with
3398 * gst_element_remove_property_notify_watch() to remove the watch again.
3403 gst_element_add_property_notify_watch (GstElement * element,
3404 const gchar * property_name, gboolean include_value)
3410 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3412 sep = (property_name != NULL) ? "::" : NULL;
3413 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3414 id = g_signal_connect (element, signal_name,
3415 G_CALLBACK (gst_element_property_notify_cb),
3416 GINT_TO_POINTER (include_value));
3417 g_free (signal_name);
3423 * gst_element_add_property_deep_notify_watch:
3424 * @element: a #GstElement to watch (recursively) for property changes
3425 * @property_name: (allow-none): name of property to watch for changes, or
3426 * NULL to watch all properties
3427 * @include_value: whether to include the new property value in the message
3429 * Returns: a watch id, which can be used in connection with
3430 * gst_element_remove_property_notify_watch() to remove the watch again.
3435 gst_element_add_property_deep_notify_watch (GstElement * element,
3436 const gchar * property_name, gboolean include_value)
3442 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3444 sep = (property_name != NULL) ? "::" : NULL;
3445 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3446 id = g_signal_connect (element, signal_name,
3447 G_CALLBACK (gst_element_property_deep_notify_cb),
3448 GINT_TO_POINTER (include_value));
3449 g_free (signal_name);
3455 * gst_element_remove_property_notify_watch:
3456 * @element: a #GstElement being watched for property changes
3457 * @watch_id: watch id to remove
3462 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3464 g_signal_handler_disconnect (element, watch_id);
3469 GstElement *element;
3470 GstElementCallAsyncFunc func;
3472 GDestroyNotify destroy_notify;
3473 } GstElementCallAsyncData;
3476 gst_element_call_async_func (gpointer data, gpointer user_data)
3478 GstElementCallAsyncData *async_data = data;
3480 async_data->func (async_data->element, async_data->user_data);
3481 if (async_data->destroy_notify)
3482 async_data->destroy_notify (async_data->user_data);
3483 gst_object_unref (async_data->element);
3484 g_free (async_data);
3488 * gst_element_call_async:
3489 * @element: a #GstElement
3490 * @func: Function to call asynchronously from another thread
3491 * @user_data: Data to pass to @func
3492 * @destroy_notify: GDestroyNotify for @user_data
3494 * Calls @func from another thread and passes @user_data to it. This is to be
3495 * used for cases when a state change has to be performed from a streaming
3496 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3499 * Calling those functions directly from the streaming thread will cause
3500 * deadlocks in many situations, as they might involve waiting for the
3501 * streaming thread to shut down from this very streaming thread.
3508 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3509 gpointer user_data, GDestroyNotify destroy_notify)
3511 GstElementCallAsyncData *async_data;
3513 g_return_if_fail (GST_IS_ELEMENT (element));
3515 async_data = g_new0 (GstElementCallAsyncData, 1);
3516 async_data->element = gst_object_ref (element);
3517 async_data->func = func;
3518 async_data->user_data = user_data;
3519 async_data->destroy_notify = destroy_notify;
3521 g_thread_pool_push (gst_element_pool, async_data, NULL);
3525 _priv_gst_element_cleanup (void)
3527 if (gst_element_pool) {
3528 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3529 gst_element_setup_thread_pool ();
3534 gst_make_element_message_details (const char *name, ...)
3536 GstStructure *structure;
3542 va_start (varargs, name);
3543 structure = gst_structure_new_valist ("details", name, varargs);