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);
726 gst_object_ref_sink (pad);
727 gst_object_unref (pad);
733 ("Pad %s already has parent when trying to add to element %s",
734 pad_name, GST_ELEMENT_NAME (element));
735 GST_OBJECT_UNLOCK (element);
737 gst_object_ref_sink (pad);
738 gst_object_unref (pad);
743 GST_OBJECT_LOCK (pad);
745 ("Trying to add pad %s to element %s, but it has no direction",
746 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
747 GST_OBJECT_UNLOCK (pad);
748 GST_OBJECT_UNLOCK (element);
754 * gst_element_remove_pad:
755 * @element: a #GstElement to remove pad from.
756 * @pad: (transfer full): the #GstPad to remove from the element.
758 * Removes @pad from @element. @pad will be destroyed if it has not been
759 * referenced elsewhere using gst_object_unparent().
761 * This function is used by plugin developers and should not be used
762 * by applications. Pads that were dynamically requested from elements
763 * with gst_element_request_pad() should be released with the
764 * gst_element_release_request_pad() function instead.
766 * Pads are not automatically deactivated so elements should perform the needed
767 * steps to deactivate the pad in case this pad is removed in the PAUSED or
768 * PLAYING state. See gst_pad_set_active() for more information about
771 * The pad and the element should be unlocked when calling this function.
773 * This function will emit the #GstElement::pad-removed signal on the element.
775 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
776 * pad does not belong to the provided element.
781 gst_element_remove_pad (GstElement * element, GstPad * pad)
785 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
786 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
788 /* locking pad to look at the name and parent */
789 GST_OBJECT_LOCK (pad);
790 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
791 GST_STR_NULL (GST_PAD_NAME (pad)));
793 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
795 GST_OBJECT_UNLOCK (pad);
798 if ((peer = gst_pad_get_peer (pad))) {
799 /* window for MT unsafeness, someone else could unlink here
800 * and then we call unlink with wrong pads. The unlink
801 * function would catch this and safely return failed. */
802 if (GST_PAD_IS_SRC (pad))
803 gst_pad_unlink (pad, peer);
805 gst_pad_unlink (peer, pad);
807 gst_object_unref (peer);
810 GST_OBJECT_LOCK (element);
811 /* remove it from the list */
812 switch (gst_pad_get_direction (pad)) {
814 element->srcpads = g_list_remove (element->srcpads, pad);
815 element->numsrcpads--;
818 element->sinkpads = g_list_remove (element->sinkpads, pad);
819 element->numsinkpads--;
822 g_critical ("Removing pad without direction???");
825 element->pads = g_list_remove (element->pads, pad);
827 element->pads_cookie++;
828 GST_OBJECT_UNLOCK (element);
830 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
831 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
832 GST_TRACER_ELEMENT_REMOVE_PAD (element, pad);
833 gst_object_unparent (GST_OBJECT_CAST (pad));
840 /* locking order is element > pad */
841 GST_OBJECT_UNLOCK (pad);
843 GST_OBJECT_LOCK (element);
844 GST_OBJECT_LOCK (pad);
845 g_critical ("Padname %s:%s does not belong to element %s when removing",
846 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
847 GST_OBJECT_UNLOCK (pad);
848 GST_OBJECT_UNLOCK (element);
854 * gst_element_no_more_pads:
855 * @element: a #GstElement
857 * Use this function to signal that the element does not expect any more pads
858 * to show up in the current pipeline. This function should be called whenever
859 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
860 * pad templates use this in combination with autopluggers to figure out that
861 * the element is done initializing its pads.
863 * This function emits the #GstElement::no-more-pads signal.
868 gst_element_no_more_pads (GstElement * element)
870 g_return_if_fail (GST_IS_ELEMENT (element));
872 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
876 pad_compare_name (GstPad * pad1, const gchar * name)
880 GST_OBJECT_LOCK (pad1);
881 result = strcmp (GST_PAD_NAME (pad1), name);
882 GST_OBJECT_UNLOCK (pad1);
888 * gst_element_get_static_pad:
889 * @element: a #GstElement to find a static pad of.
890 * @name: the name of the static #GstPad to retrieve.
892 * Retrieves a pad from @element by name. This version only retrieves
893 * already-existing (i.e. 'static') pads.
895 * Returns: (transfer full) (nullable): the requested #GstPad if
896 * found, otherwise %NULL. unref after usage.
901 gst_element_get_static_pad (GstElement * element, const gchar * name)
904 GstPad *result = NULL;
906 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
907 g_return_val_if_fail (name != NULL, NULL);
909 GST_OBJECT_LOCK (element);
911 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
913 result = GST_PAD_CAST (find->data);
914 gst_object_ref (result);
917 if (result == NULL) {
918 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
919 name, GST_ELEMENT_NAME (element));
921 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
922 GST_ELEMENT_NAME (element), name);
924 GST_OBJECT_UNLOCK (element);
930 gst_element_is_valid_request_template_name (const gchar * templ_name,
934 const gchar *templ_name_ptr, *name_ptr;
935 gboolean next_specifier;
936 guint templ_postfix_len = 0, name_postfix_len = 0;
938 g_return_val_if_fail (templ_name != NULL, FALSE);
939 g_return_val_if_fail (name != NULL, FALSE);
941 /* Is this the template name? */
942 if (strcmp (templ_name, name) == 0)
945 /* otherwise check all the specifiers */
947 /* Because of sanity checks in gst_pad_template_new(), we know that %s
948 * and %d and %u, occurring at the template_name */
949 templ_name_ptr = strchr (templ_name, '%');
951 /* check characters ahead of the specifier */
952 if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
953 || strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
957 /* %s is not allowed for multiple specifiers, just a single specifier can be
958 * accepted in gst_pad_template_new() and can not be mixed with other
959 * specifier '%u' and '%d' */
960 if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
964 name_ptr = name + (templ_name_ptr - templ_name);
966 /* search next specifier, each of specifier should be separated by '_' */
967 templ_name = strchr (templ_name_ptr, '_');
968 name = strchr (name_ptr, '_');
970 /* don't match the number of specifiers */
971 if ((templ_name && !name) || (!templ_name && name))
974 if (templ_name && name)
975 next_specifier = TRUE;
977 next_specifier = FALSE;
979 /* check characters followed by the specifier */
980 if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
981 if (next_specifier) {
982 templ_postfix_len = templ_name - (templ_name_ptr + 2);
983 name_postfix_len = name - name_ptr;
985 templ_postfix_len = strlen (templ_name_ptr + 2);
986 name_postfix_len = strlen (name_ptr);
989 if (strncmp (templ_name_ptr + 2,
990 name_ptr + name_postfix_len - templ_postfix_len,
991 templ_postfix_len) != 0) {
996 /* verify the specifier */
997 if (*(name_ptr) == '%') {
1000 len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
1002 if (strncmp (name_ptr, templ_name_ptr, len) != 0)
1006 const gchar *specifier;
1007 gchar *target = NULL;
1009 /* extract specifier when it has postfix characters */
1010 if (name_postfix_len > templ_postfix_len) {
1011 target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
1013 specifier = target ? target : name_ptr;
1015 if (*(templ_name_ptr + 1) == 'd') {
1019 tmp = g_ascii_strtoll (specifier, &endptr, 10);
1020 if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
1023 } else if (*(templ_name_ptr + 1) == 'u') {
1027 tmp = g_ascii_strtoull (specifier, &endptr, 10);
1028 if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
1035 /* otherwise we increment these from NULL to 1 */
1036 if (next_specifier) {
1040 } while (next_specifier);
1046 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
1047 const gchar * name, const GstCaps * caps)
1049 GstPad *newpad = NULL;
1050 GstElementClass *oclass;
1052 oclass = GST_ELEMENT_GET_CLASS (element);
1054 #ifndef G_DISABLE_CHECKS
1055 /* Some sanity checking here */
1059 g_return_val_if_fail (gst_element_is_valid_request_template_name
1060 (templ->name_template, name), NULL);
1062 pad = gst_element_get_static_pad (element, name);
1064 gst_object_unref (pad);
1065 /* FIXME 2.0: Change this to g_return_val_if_fail() */
1066 g_critical ("Element %s already has a pad named %s, the behaviour of "
1067 " gst_element_get_request_pad() for existing pads is undefined!",
1068 GST_ELEMENT_NAME (element), name);
1073 if (oclass->request_new_pad)
1074 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1077 gst_object_ref (newpad);
1083 * gst_element_get_request_pad:
1084 * @element: a #GstElement to find a request pad of.
1085 * @name: the name of the request #GstPad to retrieve.
1087 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1088 * retrieves request pads. The pad should be released with
1089 * gst_element_release_request_pad().
1091 * This method is slower than manually getting the pad template and calling
1092 * gst_element_request_pad() if the pads should have a specific name (e.g.
1093 * @name is "src_1" instead of "src_\%u").
1095 * Returns: (transfer full) (nullable): requested #GstPad if found,
1096 * otherwise %NULL. Release after usage.
1099 gst_element_get_request_pad (GstElement * element, const gchar * name)
1101 GstPadTemplate *templ = NULL;
1103 const gchar *req_name = NULL;
1104 gboolean templ_found = FALSE;
1106 GstElementClass *class;
1108 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1109 g_return_val_if_fail (name != NULL, NULL);
1111 class = GST_ELEMENT_GET_CLASS (element);
1113 templ = gst_element_class_get_request_pad_template (class, name);
1115 req_name = strstr (name, "%") ? NULL : name;
1118 /* there is no % in the name, try to find a matching template */
1119 list = class->padtemplates;
1120 while (!templ_found && list) {
1121 templ = (GstPadTemplate *) list->data;
1122 if (templ->presence == GST_PAD_REQUEST) {
1123 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1124 templ->name_template);
1125 if (gst_element_is_valid_request_template_name (templ->name_template,
1139 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1145 * gst_element_request_pad: (virtual request_new_pad)
1146 * @element: a #GstElement to find a request pad of.
1147 * @templ: a #GstPadTemplate of which we want a pad of.
1148 * @name: (transfer none) (allow-none): the name of the request #GstPad
1149 * to retrieve. Can be %NULL.
1150 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1151 * request. Can be %NULL.
1153 * Retrieves a request pad from the element according to the provided template.
1154 * Pad templates can be looked up using
1155 * gst_element_factory_get_static_pad_templates().
1157 * The pad should be released with gst_element_release_request_pad().
1159 * Returns: (transfer full) (nullable): requested #GstPad if found,
1160 * otherwise %NULL. Release after usage.
1163 gst_element_request_pad (GstElement * element,
1164 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1166 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1167 g_return_val_if_fail (templ != NULL, NULL);
1168 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1170 return _gst_element_request_pad (element, templ, name, caps);
1173 static GstIterator *
1174 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1176 GstIterator *result;
1178 GST_OBJECT_LOCK (element);
1179 result = gst_iterator_new_list (GST_TYPE_PAD,
1180 GST_OBJECT_GET_LOCK (element),
1181 &element->pads_cookie, padlist, (GObject *) element, NULL);
1182 GST_OBJECT_UNLOCK (element);
1188 * gst_element_iterate_pads:
1189 * @element: a #GstElement to iterate pads of.
1191 * Retrieves an iterator of @element's pads. The iterator should
1192 * be freed after usage. Also more specialized iterators exists such as
1193 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1195 * The order of pads returned by the iterator will be the order in which
1196 * the pads were added to the element.
1198 * Returns: (transfer full): the #GstIterator of #GstPad.
1203 gst_element_iterate_pads (GstElement * element)
1205 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1207 return gst_element_iterate_pad_list (element, &element->pads);
1211 * gst_element_iterate_src_pads:
1212 * @element: a #GstElement.
1214 * Retrieves an iterator of @element's source pads.
1216 * The order of pads returned by the iterator will be the order in which
1217 * the pads were added to the element.
1219 * Returns: (transfer full): the #GstIterator of #GstPad.
1224 gst_element_iterate_src_pads (GstElement * element)
1226 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1228 return gst_element_iterate_pad_list (element, &element->srcpads);
1232 * gst_element_iterate_sink_pads:
1233 * @element: a #GstElement.
1235 * Retrieves an iterator of @element's sink pads.
1237 * The order of pads returned by the iterator will be the order in which
1238 * the pads were added to the element.
1240 * Returns: (transfer full): the #GstIterator of #GstPad.
1245 gst_element_iterate_sink_pads (GstElement * element)
1247 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1249 return gst_element_iterate_pad_list (element, &element->sinkpads);
1253 * gst_element_class_add_pad_template:
1254 * @klass: the #GstElementClass to add the pad template to.
1255 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1257 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1258 * functions of classes. If a pad template with the same name as an already
1259 * existing one is added the old one is replaced by the new one.
1263 gst_element_class_add_pad_template (GstElementClass * klass,
1264 GstPadTemplate * templ)
1266 GList *template_list = klass->padtemplates;
1268 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1269 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1271 /* If we already have a pad template with the same name replace the
1273 while (template_list) {
1274 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1276 /* Found pad with the same name, replace and return */
1277 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1278 gst_object_unref (padtempl);
1279 template_list->data = templ;
1282 template_list = g_list_next (template_list);
1285 /* Take ownership of the floating ref */
1286 gst_object_ref_sink (templ);
1288 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1289 klass->numpadtemplates++;
1293 * gst_element_class_add_static_pad_template:
1294 * @klass: the #GstElementClass to add the pad template to.
1295 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1297 * Adds a pad template to an element class based on the static pad template
1298 * @templ. This is mainly used in the _class_init functions of element
1299 * implementations. If a pad template with the same name already exists,
1300 * the old one is replaced by the new one.
1305 gst_element_class_add_static_pad_template (GstElementClass * klass,
1306 GstStaticPadTemplate * static_templ)
1308 gst_element_class_add_pad_template (klass,
1309 gst_static_pad_template_get (static_templ));
1313 * gst_element_class_add_metadata:
1314 * @klass: class to set metadata for
1315 * @key: the key to set
1316 * @value: the value to set
1318 * Set @key with @value as metadata in @klass.
1321 gst_element_class_add_metadata (GstElementClass * klass,
1322 const gchar * key, const gchar * value)
1324 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1325 g_return_if_fail (key != NULL);
1326 g_return_if_fail (value != NULL);
1328 gst_structure_set ((GstStructure *) klass->metadata,
1329 key, G_TYPE_STRING, value, NULL);
1333 * gst_element_class_add_static_metadata:
1334 * @klass: class to set metadata for
1335 * @key: the key to set
1336 * @value: the value to set
1338 * Set @key with @value as metadata in @klass.
1340 * Same as gst_element_class_add_metadata(), but @value must be a static string
1341 * or an inlined string, as it will not be copied. (GStreamer plugins will
1342 * be made resident once loaded, so this function can be used even from
1343 * dynamically loaded plugins.)
1346 gst_element_class_add_static_metadata (GstElementClass * klass,
1347 const gchar * key, const gchar * value)
1349 GValue val = G_VALUE_INIT;
1351 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1352 g_return_if_fail (key != NULL);
1353 g_return_if_fail (value != NULL);
1355 g_value_init (&val, G_TYPE_STRING);
1356 g_value_set_static_string (&val, value);
1357 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1361 * gst_element_class_set_metadata:
1362 * @klass: class to set metadata for
1363 * @longname: The long English name of the element. E.g. "File Sink"
1364 * @classification: String describing the type of element, as an unordered list
1365 * separated with slashes ('/'). See draft-klass.txt of the design docs
1366 * for more details and common types. E.g: "Sink/File"
1367 * @description: Sentence describing the purpose of the element.
1368 * E.g: "Write stream to a file"
1369 * @author: Name and contact details of the author(s). Use \n to separate
1370 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1372 * Sets the detailed information for a #GstElementClass.
1373 * > This function is for use in _class_init functions only.
1376 gst_element_class_set_metadata (GstElementClass * klass,
1377 const gchar * longname, const gchar * classification,
1378 const gchar * description, const gchar * author)
1380 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1381 g_return_if_fail (longname != NULL && *longname != '\0');
1382 g_return_if_fail (classification != NULL && *classification != '\0');
1383 g_return_if_fail (description != NULL && *description != '\0');
1384 g_return_if_fail (author != NULL && *author != '\0');
1386 gst_structure_id_set ((GstStructure *) klass->metadata,
1387 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1388 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1389 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1390 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1394 * gst_element_class_set_static_metadata:
1395 * @klass: class to set metadata for
1396 * @longname: The long English name of the element. E.g. "File Sink"
1397 * @classification: String describing the type of element, as an unordered list
1398 * separated with slashes ('/'). See draft-klass.txt of the design docs
1399 * for more details and common types. E.g: "Sink/File"
1400 * @description: Sentence describing the purpose of the element.
1401 * E.g: "Write stream to a file"
1402 * @author: Name and contact details of the author(s). Use \n to separate
1403 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1405 * Sets the detailed information for a #GstElementClass.
1407 * > This function is for use in _class_init functions only.
1409 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1410 * @description, and @author must be static strings or inlined strings, as
1411 * they will not be copied. (GStreamer plugins will be made resident once
1412 * loaded, so this function can be used even from dynamically loaded plugins.)
1415 gst_element_class_set_static_metadata (GstElementClass * klass,
1416 const gchar * longname, const gchar * classification,
1417 const gchar * description, const gchar * author)
1419 GstStructure *s = (GstStructure *) klass->metadata;
1420 GValue val = G_VALUE_INIT;
1422 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1423 g_return_if_fail (longname != NULL && *longname != '\0');
1424 g_return_if_fail (classification != NULL && *classification != '\0');
1425 g_return_if_fail (description != NULL && *description != '\0');
1426 g_return_if_fail (author != NULL && *author != '\0');
1428 g_value_init (&val, G_TYPE_STRING);
1430 g_value_set_static_string (&val, longname);
1431 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1433 g_value_set_static_string (&val, classification);
1434 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1436 g_value_set_static_string (&val, description);
1437 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1440 g_value_set_static_string (&val, author);
1441 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1445 * gst_element_class_get_metadata:
1446 * @klass: class to get metadata for
1447 * @key: the key to get
1449 * Get metadata with @key in @klass.
1451 * Returns: the metadata for @key.
1454 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1456 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1457 g_return_val_if_fail (key != NULL, NULL);
1459 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1463 * gst_element_class_get_pad_template_list:
1464 * @element_class: a #GstElementClass to get pad templates of.
1466 * Retrieves a list of the pad templates associated with @element_class. The
1467 * list must not be modified by the calling code.
1468 * > If you use this function in the #GInstanceInitFunc of an object class
1469 * > that has subclasses, make sure to pass the g_class parameter of the
1470 * > #GInstanceInitFunc here.
1472 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1476 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1478 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1480 return element_class->padtemplates;
1484 * gst_element_class_get_pad_template:
1485 * @element_class: a #GstElementClass to get the pad template of.
1486 * @name: the name of the #GstPadTemplate to get.
1488 * Retrieves a padtemplate from @element_class with the given name.
1489 * > If you use this function in the #GInstanceInitFunc of an object class
1490 * > that has subclasses, make sure to pass the g_class parameter of the
1491 * > #GInstanceInitFunc here.
1493 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1494 * given name, or %NULL if none was found. No unreferencing is
1498 gst_element_class_get_pad_template (GstElementClass *
1499 element_class, const gchar * name)
1503 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1504 g_return_val_if_fail (name != NULL, NULL);
1506 padlist = element_class->padtemplates;
1509 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1511 if (strcmp (padtempl->name_template, name) == 0)
1514 padlist = g_list_next (padlist);
1520 static GstPadTemplate *
1521 gst_element_class_get_request_pad_template (GstElementClass *
1522 element_class, const gchar * name)
1524 GstPadTemplate *tmpl;
1526 tmpl = gst_element_class_get_pad_template (element_class, name);
1527 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1533 /* get a random pad on element of the given direction.
1534 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1537 gst_element_get_random_pad (GstElement * element,
1538 gboolean need_linked, GstPadDirection dir)
1540 GstPad *result = NULL;
1543 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1547 GST_OBJECT_LOCK (element);
1548 pads = element->srcpads;
1551 GST_OBJECT_LOCK (element);
1552 pads = element->sinkpads;
1555 goto wrong_direction;
1557 for (; pads; pads = g_list_next (pads)) {
1558 GstPad *pad = GST_PAD_CAST (pads->data);
1560 GST_OBJECT_LOCK (pad);
1561 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1562 GST_DEBUG_PAD_NAME (pad));
1564 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1565 /* if we require a linked pad, and it is not linked, continue the
1567 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1568 GST_DEBUG_PAD_NAME (pad));
1569 GST_OBJECT_UNLOCK (pad);
1572 /* found a pad, stop search */
1573 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1574 GST_DEBUG_PAD_NAME (pad));
1575 GST_OBJECT_UNLOCK (pad);
1581 gst_object_ref (result);
1583 GST_OBJECT_UNLOCK (element);
1587 /* ERROR handling */
1590 g_warning ("unknown pad direction %d", dir);
1596 gst_element_default_send_event (GstElement * element, GstEvent * event)
1598 gboolean result = FALSE;
1601 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1602 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1603 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1606 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1607 "pushing %s event to random %s pad %s:%s",
1608 GST_EVENT_TYPE_NAME (event),
1609 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1610 GST_DEBUG_PAD_NAME (pad));
1612 result = gst_pad_send_event (pad, event);
1613 gst_object_unref (pad);
1615 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1616 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1617 gst_event_unref (event);
1623 * gst_element_send_event:
1624 * @element: a #GstElement to send the event to.
1625 * @event: (transfer full): the #GstEvent to send to the element.
1627 * Sends an event to an element. If the element doesn't implement an
1628 * event handler, the event will be pushed on a random linked sink pad for
1629 * downstream events or a random linked source pad for upstream events.
1631 * This function takes ownership of the provided event so you should
1632 * gst_event_ref() it if you want to reuse the event after this call.
1636 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1637 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1640 gst_element_send_event (GstElement * element, GstEvent * event)
1642 GstElementClass *oclass;
1643 gboolean result = FALSE;
1645 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1646 g_return_val_if_fail (event != NULL, FALSE);
1648 oclass = GST_ELEMENT_GET_CLASS (element);
1650 GST_STATE_LOCK (element);
1651 if (oclass->send_event) {
1652 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1653 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1654 result = oclass->send_event (element, event);
1656 gst_event_unref (event);
1658 GST_STATE_UNLOCK (element);
1665 * @element: a #GstElement to send the event to.
1666 * @rate: The new playback rate
1667 * @format: The format of the seek values
1668 * @flags: The optional seek flags.
1669 * @start_type: The type and flags for the new start position
1670 * @start: The value of the new start position
1671 * @stop_type: The type and flags for the new stop position
1672 * @stop: The value of the new stop position
1674 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1675 * the parameters. The seek event is sent to the element using
1676 * gst_element_send_event().
1680 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1681 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1684 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1685 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1686 GstSeekType stop_type, gint64 stop)
1691 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1694 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1696 result = gst_element_send_event (element, event);
1702 gst_element_default_query (GstElement * element, GstQuery * query)
1704 gboolean result = FALSE;
1707 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1709 result = gst_pad_query (pad, query);
1711 gst_object_unref (pad);
1713 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1715 GstPad *peer = gst_pad_get_peer (pad);
1718 result = gst_pad_query (peer, query);
1720 gst_object_unref (peer);
1722 gst_object_unref (pad);
1729 * gst_element_query:
1730 * @element: a #GstElement to perform the query on.
1731 * @query: (transfer none): the #GstQuery.
1733 * Performs a query on the given element.
1735 * For elements that don't implement a query handler, this function
1736 * forwards the query to a random srcpad or to the peer of a
1737 * random linked sinkpad of this element.
1739 * Please note that some queries might need a running pipeline to work.
1741 * Returns: %TRUE if the query could be performed.
1746 gst_element_query (GstElement * element, GstQuery * query)
1748 GstElementClass *klass;
1749 gboolean res = FALSE;
1751 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1752 g_return_val_if_fail (query != NULL, FALSE);
1754 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1756 klass = GST_ELEMENT_GET_CLASS (element);
1758 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1759 GST_ELEMENT_NAME (element));
1760 res = klass->query (element, query);
1763 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1768 gst_element_post_message_default (GstElement * element, GstMessage * message)
1771 gboolean result = FALSE;
1773 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1774 g_return_val_if_fail (message != NULL, FALSE);
1776 GST_OBJECT_LOCK (element);
1779 if (G_UNLIKELY (bus == NULL))
1782 gst_object_ref (bus);
1783 GST_OBJECT_UNLOCK (element);
1785 /* we release the element lock when posting the message so that any
1786 * (synchronous) message handlers can operate on the element */
1787 result = gst_bus_post (bus, message);
1788 gst_object_unref (bus);
1795 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1796 "not posting message %p: no bus", message);
1797 GST_OBJECT_UNLOCK (element);
1798 gst_message_unref (message);
1804 * gst_element_post_message:
1805 * @element: a #GstElement posting the message
1806 * @message: (transfer full): a #GstMessage to post
1808 * Post a message on the element's #GstBus. This function takes ownership of the
1809 * message; if you want to access the message after this call, you should add an
1810 * additional reference before calling.
1812 * Returns: %TRUE if the message was successfully posted. The function returns
1813 * %FALSE if the element did not have a bus.
1818 gst_element_post_message (GstElement * element, GstMessage * message)
1820 GstElementClass *klass;
1821 gboolean res = FALSE;
1823 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1824 g_return_val_if_fail (message != NULL, FALSE);
1826 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1828 klass = GST_ELEMENT_GET_CLASS (element);
1829 if (klass->post_message)
1830 res = klass->post_message (element, message);
1832 gst_message_unref (message);
1834 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1839 * _gst_element_error_printf:
1840 * @format: (allow-none): the printf-like format to use, or %NULL
1842 * This function is only used internally by the gst_element_error() macro.
1844 * Returns: (transfer full) (nullable): a newly allocated string, or
1845 * %NULL if the format was %NULL or ""
1850 _gst_element_error_printf (const gchar * format, ...)
1861 va_start (args, format);
1863 len = __gst_vasprintf (&buffer, format, args);
1874 * gst_element_message_full_with_details:
1875 * @element: a #GstElement to send message from
1876 * @type: the #GstMessageType
1877 * @domain: the GStreamer GError domain this message belongs to
1878 * @code: the GError code belonging to the domain
1879 * @text: (allow-none) (transfer full): an allocated text string to be used
1880 * as a replacement for the default message connected to code,
1882 * @debug: (allow-none) (transfer full): an allocated debug message to be
1883 * used as a replacement for the default debugging information,
1885 * @file: the source code file where the error was generated
1886 * @function: the source code function where the error was generated
1887 * @line: the source code line where the error was generated
1888 * @structure:(transfer full): optional details structure
1890 * Post an error, warning or info message on the bus from inside an element.
1892 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1893 * #GST_MESSAGE_INFO.
1897 void gst_element_message_full_with_details
1898 (GstElement * element, GstMessageType type,
1899 GQuark domain, gint code, gchar * text,
1900 gchar * debug, const gchar * file, const gchar * function, gint line,
1901 GstStructure * structure)
1903 GError *gerror = NULL;
1907 gboolean has_debug = TRUE;
1908 GstMessage *message = NULL;
1911 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1912 g_return_if_fail (GST_IS_ELEMENT (element));
1913 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1914 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1916 /* check if we send the given text or the default error text */
1917 if ((text == NULL) || (text[0] == 0)) {
1918 /* text could have come from g_strdup_printf (""); */
1920 sent_text = gst_error_get_message (domain, code);
1924 /* construct a sent_debug with extra information from source */
1925 if ((debug == NULL) || (debug[0] == 0)) {
1926 /* debug could have come from g_strdup_printf (""); */
1930 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1932 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1933 file, line, function, name, debug);
1935 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1936 file, line, function, name);
1940 /* create gerror and post message */
1941 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1943 gerror = g_error_new_literal (domain, code, sent_text);
1946 case GST_MESSAGE_ERROR:
1948 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1949 sent_debug, structure);
1951 case GST_MESSAGE_WARNING:
1953 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1954 gerror, sent_debug, structure);
1956 case GST_MESSAGE_INFO:
1958 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1959 sent_debug, structure);
1962 g_assert_not_reached ();
1966 gst_element_post_message (element, message);
1968 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1969 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1972 g_error_free (gerror);
1973 g_free (sent_debug);
1978 * gst_element_message_full:
1979 * @element: a #GstElement to send message from
1980 * @type: the #GstMessageType
1981 * @domain: the GStreamer GError domain this message belongs to
1982 * @code: the GError code belonging to the domain
1983 * @text: (allow-none) (transfer full): an allocated text string to be used
1984 * as a replacement for the default message connected to code,
1986 * @debug: (allow-none) (transfer full): an allocated debug message to be
1987 * used as a replacement for the default debugging information,
1989 * @file: the source code file where the error was generated
1990 * @function: the source code function where the error was generated
1991 * @line: the source code line where the error was generated
1993 * Post an error, warning or info message on the bus from inside an element.
1995 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1996 * #GST_MESSAGE_INFO.
2000 void gst_element_message_full
2001 (GstElement * element, GstMessageType type,
2002 GQuark domain, gint code, gchar * text,
2003 gchar * debug, const gchar * file, const gchar * function, gint line)
2005 gst_element_message_full_with_details (element, type, domain, code, text,
2006 debug, file, function, line, NULL);
2010 * gst_element_is_locked_state:
2011 * @element: a #GstElement.
2013 * Checks if the state of an element is locked.
2014 * If the state of an element is locked, state changes of the parent don't
2015 * affect the element.
2016 * This way you can leave currently unused elements inside bins. Just lock their
2017 * state before changing the state from #GST_STATE_NULL.
2021 * Returns: %TRUE, if the element's state is locked.
2024 gst_element_is_locked_state (GstElement * element)
2028 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2030 GST_OBJECT_LOCK (element);
2031 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2032 GST_OBJECT_UNLOCK (element);
2038 * gst_element_set_locked_state:
2039 * @element: a #GstElement
2040 * @locked_state: %TRUE to lock the element's state
2042 * Locks the state of an element, so state changes of the parent don't affect
2043 * this element anymore.
2047 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2048 * or the elements state-locking needed no change.
2051 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2055 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2057 GST_OBJECT_LOCK (element);
2058 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2060 if (G_UNLIKELY (old == locked_state))
2064 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2065 GST_ELEMENT_NAME (element));
2066 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2068 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2069 GST_ELEMENT_NAME (element));
2070 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2072 GST_OBJECT_UNLOCK (element);
2078 GST_CAT_DEBUG (GST_CAT_STATES,
2079 "elements %s was already in locked state %d",
2080 GST_ELEMENT_NAME (element), old);
2081 GST_OBJECT_UNLOCK (element);
2088 * gst_element_sync_state_with_parent:
2089 * @element: a #GstElement.
2091 * Tries to change the state of the element to the same as its parent.
2092 * If this function returns %FALSE, the state of element is undefined.
2094 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2099 gst_element_sync_state_with_parent (GstElement * element)
2103 GstStateChangeReturn ret;
2105 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2107 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2108 GstState parent_current, parent_pending;
2110 GST_OBJECT_LOCK (parent);
2111 parent_current = GST_STATE (parent);
2112 parent_pending = GST_STATE_PENDING (parent);
2113 GST_OBJECT_UNLOCK (parent);
2115 /* set to pending if there is one, else we set it to the current state of
2117 if (parent_pending != GST_STATE_VOID_PENDING)
2118 target = parent_pending;
2120 target = parent_current;
2122 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2123 "syncing state (%s) to parent %s %s (%s, %s)",
2124 gst_element_state_get_name (GST_STATE (element)),
2125 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2126 gst_element_state_get_name (parent_current),
2127 gst_element_state_get_name (parent_pending));
2129 ret = gst_element_set_state (element, target);
2130 if (ret == GST_STATE_CHANGE_FAILURE)
2133 gst_object_unref (parent);
2137 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2144 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2145 "syncing state failed (%s)",
2146 gst_element_state_change_return_get_name (ret));
2147 gst_object_unref (parent);
2153 static GstStateChangeReturn
2154 gst_element_get_state_func (GstElement * element,
2155 GstState * state, GstState * pending, GstClockTime timeout)
2157 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2158 GstState old_pending;
2160 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2161 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2163 GST_OBJECT_LOCK (element);
2164 ret = GST_STATE_RETURN (element);
2165 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2166 gst_element_state_change_return_get_name (ret));
2168 /* we got an error, report immediately */
2169 if (ret == GST_STATE_CHANGE_FAILURE)
2172 /* we got no_preroll, report immediately */
2173 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2176 /* no need to wait async if we are not async */
2177 if (ret != GST_STATE_CHANGE_ASYNC)
2180 old_pending = GST_STATE_PENDING (element);
2181 if (old_pending != GST_STATE_VOID_PENDING) {
2185 /* get cookie to detect state changes during waiting */
2186 cookie = element->state_cookie;
2188 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2189 "waiting for element to commit state");
2191 /* we have a pending state change, wait for it to complete */
2192 if (timeout != GST_CLOCK_TIME_NONE) {
2194 /* make timeout absolute */
2195 end_time = g_get_monotonic_time () + (timeout / 1000);
2196 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2198 GST_STATE_WAIT (element);
2203 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2204 /* timeout triggered */
2205 ret = GST_STATE_CHANGE_ASYNC;
2207 if (cookie != element->state_cookie)
2210 /* could be success or failure */
2211 if (old_pending == GST_STATE (element)) {
2212 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2213 ret = GST_STATE_CHANGE_SUCCESS;
2215 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2216 ret = GST_STATE_CHANGE_FAILURE;
2219 /* if nothing is pending anymore we can return SUCCESS */
2220 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2221 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2222 ret = GST_STATE_CHANGE_SUCCESS;
2228 *state = GST_STATE (element);
2230 *pending = GST_STATE_PENDING (element);
2232 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2233 "state current: %s, pending: %s, result: %s",
2234 gst_element_state_get_name (GST_STATE (element)),
2235 gst_element_state_get_name (GST_STATE_PENDING (element)),
2236 gst_element_state_change_return_get_name (ret));
2237 GST_OBJECT_UNLOCK (element);
2244 *state = GST_STATE_VOID_PENDING;
2246 *pending = GST_STATE_VOID_PENDING;
2248 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2250 GST_OBJECT_UNLOCK (element);
2252 return GST_STATE_CHANGE_FAILURE;
2257 * gst_element_get_state:
2258 * @element: a #GstElement to get the state of.
2259 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2261 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2262 * state. Can be %NULL.
2263 * @timeout: a #GstClockTime to specify the timeout for an async
2264 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2266 * Gets the state of the element.
2268 * For elements that performed an ASYNC state change, as reported by
2269 * gst_element_set_state(), this function will block up to the
2270 * specified timeout value for the state change to complete.
2271 * If the element completes the state change or goes into
2272 * an error, this function returns immediately with a return value of
2273 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2275 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2276 * returns the current and pending state immediately.
2278 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2279 * successfully changed its state but is not able to provide data yet.
2280 * This mostly happens for live sources that only produce data in
2281 * %GST_STATE_PLAYING. While the state change return is equivalent to
2282 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2283 * some sink elements might not be able to complete their state change because
2284 * an element is not producing data to complete the preroll. When setting the
2285 * element to playing, the preroll will complete and playback will start.
2287 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2288 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2289 * element is still performing a state change or
2290 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2294 GstStateChangeReturn
2295 gst_element_get_state (GstElement * element,
2296 GstState * state, GstState * pending, GstClockTime timeout)
2298 GstElementClass *oclass;
2299 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2301 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2303 oclass = GST_ELEMENT_GET_CLASS (element);
2305 if (oclass->get_state)
2306 result = (oclass->get_state) (element, state, pending, timeout);
2312 * gst_element_abort_state:
2313 * @element: a #GstElement to abort the state of.
2315 * Abort the state change of the element. This function is used
2316 * by elements that do asynchronous state changes and find out
2317 * something is wrong.
2319 * This function should be called with the STATE_LOCK held.
2324 gst_element_abort_state (GstElement * element)
2328 #ifndef GST_DISABLE_GST_DEBUG
2332 g_return_if_fail (GST_IS_ELEMENT (element));
2334 GST_OBJECT_LOCK (element);
2335 pending = GST_STATE_PENDING (element);
2337 if (pending == GST_STATE_VOID_PENDING ||
2338 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2339 goto nothing_aborted;
2341 #ifndef GST_DISABLE_GST_DEBUG
2342 old_state = GST_STATE (element);
2344 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2345 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2346 gst_element_state_get_name (pending));
2350 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2352 GST_STATE_BROADCAST (element);
2353 GST_OBJECT_UNLOCK (element);
2359 GST_OBJECT_UNLOCK (element);
2364 /* Not static because GstBin has manual state handling too */
2366 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2367 GstState newstate, GstState pending)
2369 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2370 GstMessage *message;
2372 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2373 "notifying about state-changed %s to %s (%s pending)",
2374 gst_element_state_get_name (oldstate),
2375 gst_element_state_get_name (newstate),
2376 gst_element_state_get_name (pending));
2378 if (klass->state_changed)
2379 klass->state_changed (element, oldstate, newstate, pending);
2381 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2382 oldstate, newstate, pending);
2383 gst_element_post_message (element, message);
2387 * gst_element_continue_state:
2388 * @element: a #GstElement to continue the state change of.
2389 * @ret: The previous state return value
2391 * Commit the state change of the element and proceed to the next
2392 * pending state if any. This function is used
2393 * by elements that do asynchronous state changes.
2394 * The core will normally call this method automatically when an
2395 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2397 * If after calling this method the element still has not reached
2398 * the pending state, the next state change is performed.
2400 * This method is used internally and should normally not be called by plugins
2403 * Returns: The result of the commit state change.
2407 GstStateChangeReturn
2408 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2410 GstStateChangeReturn old_ret;
2411 GstState old_state, old_next;
2412 GstState current, next, pending;
2413 GstStateChange transition;
2415 GST_OBJECT_LOCK (element);
2416 old_ret = GST_STATE_RETURN (element);
2417 GST_STATE_RETURN (element) = ret;
2418 pending = GST_STATE_PENDING (element);
2420 /* check if there is something to commit */
2421 if (pending == GST_STATE_VOID_PENDING)
2422 goto nothing_pending;
2424 old_state = GST_STATE (element);
2425 /* this is the state we should go to next */
2426 old_next = GST_STATE_NEXT (element);
2427 /* update current state */
2428 current = GST_STATE (element) = old_next;
2430 /* see if we reached the final state */
2431 if (pending == current)
2434 next = GST_STATE_GET_NEXT (current, pending);
2435 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2437 GST_STATE_NEXT (element) = next;
2439 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2440 GST_OBJECT_UNLOCK (element);
2442 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2443 "committing state from %s to %s, pending %s, next %s",
2444 gst_element_state_get_name (old_state),
2445 gst_element_state_get_name (old_next),
2446 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2448 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2450 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2451 "continue state change %s to %s, final %s",
2452 gst_element_state_get_name (current),
2453 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2455 ret = gst_element_change_state (element, transition);
2461 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2462 GST_OBJECT_UNLOCK (element);
2467 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2468 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2470 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2471 "completed state change to %s", gst_element_state_get_name (pending));
2472 GST_OBJECT_UNLOCK (element);
2474 /* don't post silly messages with the same state. This can happen
2475 * when an element state is changed to what it already was. For bins
2476 * this can be the result of a lost state, which we check with the
2477 * previous return value.
2478 * We do signal the cond though as a _get_state() might be blocking
2480 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2481 _priv_gst_element_state_changed (element, old_state, old_next,
2482 GST_STATE_VOID_PENDING);
2484 GST_STATE_BROADCAST (element);
2491 * gst_element_lost_state:
2492 * @element: a #GstElement the state is lost of
2494 * Brings the element to the lost state. The current state of the
2495 * element is copied to the pending state so that any call to
2496 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2498 * An ASYNC_START message is posted. If the element was PLAYING, it will
2499 * go to PAUSED. The element will be restored to its PLAYING state by
2500 * the parent pipeline when it prerolls again.
2502 * This is mostly used for elements that lost their preroll buffer
2503 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2504 * they will go to their pending state again when a new preroll buffer is
2505 * queued. This function can only be called when the element is currently
2506 * not in error or an async state change.
2508 * This function is used internally and should normally not be called from
2509 * plugins or applications.
2512 gst_element_lost_state (GstElement * element)
2514 GstState old_state, new_state;
2515 GstMessage *message;
2517 g_return_if_fail (GST_IS_ELEMENT (element));
2519 GST_OBJECT_LOCK (element);
2520 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2523 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2524 goto only_async_start;
2526 old_state = GST_STATE (element);
2528 /* when we were PLAYING, the new state is PAUSED. We will also not
2529 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2530 * when we preroll. */
2531 if (old_state > GST_STATE_PAUSED)
2532 new_state = GST_STATE_PAUSED;
2534 new_state = old_state;
2536 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2537 "lost state of %s to %s", gst_element_state_get_name (old_state),
2538 gst_element_state_get_name (new_state));
2540 GST_STATE (element) = new_state;
2541 GST_STATE_NEXT (element) = new_state;
2542 GST_STATE_PENDING (element) = new_state;
2543 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2544 GST_OBJECT_UNLOCK (element);
2546 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2548 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2549 gst_element_post_message (element, message);
2555 GST_OBJECT_UNLOCK (element);
2560 GST_OBJECT_UNLOCK (element);
2562 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2563 gst_element_post_message (element, message);
2569 * gst_element_set_state:
2570 * @element: a #GstElement to change state of.
2571 * @state: the element's new #GstState.
2573 * Sets the state of the element. This function will try to set the
2574 * requested state by going through all the intermediary states and calling
2575 * the class's state change function for each.
2577 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2578 * element will perform the remainder of the state change asynchronously in
2580 * An application can use gst_element_get_state() to wait for the completion
2581 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2582 * %GST_MESSAGE_STATE_CHANGED on the bus.
2584 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2585 * #GST_STATE_CHANGE_ASYNC.
2587 * Returns: Result of the state change using #GstStateChangeReturn.
2591 GstStateChangeReturn
2592 gst_element_set_state (GstElement * element, GstState state)
2594 GstElementClass *oclass;
2595 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2597 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2599 oclass = GST_ELEMENT_GET_CLASS (element);
2601 if (oclass->set_state)
2602 result = (oclass->set_state) (element, state);
2608 * default set state function, calculates the next state based
2609 * on current state and calls the change_state function
2611 static GstStateChangeReturn
2612 gst_element_set_state_func (GstElement * element, GstState state)
2614 GstState current, next, old_pending;
2615 GstStateChangeReturn ret;
2616 GstStateChange transition;
2617 GstStateChangeReturn old_ret;
2619 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2621 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2622 gst_element_state_get_name (state));
2624 /* state lock is taken to protect the set_state() and get_state()
2625 * procedures, it does not lock any variables. */
2626 GST_STATE_LOCK (element);
2628 /* now calculate how to get to the new state */
2629 GST_OBJECT_LOCK (element);
2630 old_ret = GST_STATE_RETURN (element);
2631 /* previous state change returned an error, remove all pending
2632 * and next states */
2633 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2634 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2635 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2636 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2639 current = GST_STATE (element);
2640 next = GST_STATE_NEXT (element);
2641 old_pending = GST_STATE_PENDING (element);
2643 /* this is the (new) state we should go to. TARGET is the last state we set on
2645 if (state != GST_STATE_TARGET (element)) {
2646 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2647 "setting target state to %s", gst_element_state_get_name (state));
2648 GST_STATE_TARGET (element) = state;
2649 /* increment state cookie so that we can track each state change. We only do
2650 * this if this is actually a new state change. */
2651 element->state_cookie++;
2653 GST_STATE_PENDING (element) = state;
2655 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2656 "current %s, old_pending %s, next %s, old return %s",
2657 gst_element_state_get_name (current),
2658 gst_element_state_get_name (old_pending),
2659 gst_element_state_get_name (next),
2660 gst_element_state_change_return_get_name (old_ret));
2662 /* if the element was busy doing a state change, we just update the
2663 * target state, it'll get to it async then. */
2664 if (old_pending != GST_STATE_VOID_PENDING) {
2665 /* upwards state change will happen ASYNC */
2666 if (old_pending <= state)
2668 /* element is going to this state already */
2669 else if (next == state)
2671 /* element was performing an ASYNC upward state change and
2672 * we request to go downward again. Start from the next pending
2674 else if (next > state
2675 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2679 next = GST_STATE_GET_NEXT (current, state);
2680 /* now we store the next state */
2681 GST_STATE_NEXT (element) = next;
2682 /* mark busy, we need to check that there is actually a state change
2683 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2684 * the default element change_state function has no way to know what the
2685 * old value was... could consider this a FIXME...*/
2686 if (current != next)
2687 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2689 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2691 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2692 "%s: setting state from %s to %s",
2693 (next != state ? "intermediate" : "final"),
2694 gst_element_state_get_name (current), gst_element_state_get_name (next));
2696 /* now signal any waiters, they will error since the cookie was incremented */
2697 GST_STATE_BROADCAST (element);
2699 GST_OBJECT_UNLOCK (element);
2701 ret = gst_element_change_state (element, transition);
2703 GST_STATE_UNLOCK (element);
2705 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2706 gst_element_state_change_return_get_name (ret));
2712 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2713 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2714 "element was busy with async state change");
2715 GST_OBJECT_UNLOCK (element);
2717 GST_STATE_UNLOCK (element);
2719 return GST_STATE_CHANGE_ASYNC;
2724 * gst_element_change_state:
2725 * @element: a #GstElement
2726 * @transition: the requested transition
2728 * Perform @transition on @element.
2730 * This function must be called with STATE_LOCK held and is mainly used
2733 * Returns: the #GstStateChangeReturn of the state transition.
2735 GstStateChangeReturn
2736 gst_element_change_state (GstElement * element, GstStateChange transition)
2738 GstElementClass *oclass;
2739 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2741 oclass = GST_ELEMENT_GET_CLASS (element);
2743 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2745 /* call the state change function so it can set the state */
2746 if (oclass->change_state)
2747 ret = (oclass->change_state) (element, transition);
2749 ret = GST_STATE_CHANGE_FAILURE;
2751 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2754 case GST_STATE_CHANGE_FAILURE:
2755 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2756 "have FAILURE change_state return");
2757 /* state change failure */
2758 gst_element_abort_state (element);
2760 case GST_STATE_CHANGE_ASYNC:
2764 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2765 "element will change state ASYNC");
2767 target = GST_STATE_TARGET (element);
2769 if (target > GST_STATE_READY)
2772 /* else we just continue the state change downwards */
2773 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2774 "forcing commit state %s <= %s",
2775 gst_element_state_get_name (target),
2776 gst_element_state_get_name (GST_STATE_READY));
2778 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2781 case GST_STATE_CHANGE_SUCCESS:
2782 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2783 "element changed state SUCCESS");
2784 /* we can commit the state now which will proceeed to
2786 ret = gst_element_continue_state (element, ret);
2788 case GST_STATE_CHANGE_NO_PREROLL:
2789 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2790 "element changed state NO_PREROLL");
2791 /* we can commit the state now which will proceeed to
2793 ret = gst_element_continue_state (element, ret);
2796 goto invalid_return;
2799 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2804 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2812 GST_OBJECT_LOCK (element);
2813 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2814 g_critical ("%s: unknown return value %d from a state change function",
2815 GST_ELEMENT_NAME (element), ret);
2817 /* we are in error now */
2818 ret = GST_STATE_CHANGE_FAILURE;
2819 GST_STATE_RETURN (element) = ret;
2820 GST_OBJECT_UNLOCK (element);
2826 /* gst_iterator_fold functions for pads_activate
2827 * Stop the iterator if activating one pad failed, but only if that pad
2828 * has not been removed from the element. */
2830 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2832 GstPad *pad = g_value_get_object (vpad);
2833 gboolean cont = TRUE;
2835 if (!gst_pad_set_active (pad, *active)) {
2836 if (GST_PAD_PARENT (pad) != NULL) {
2838 g_value_set_boolean (ret, FALSE);
2845 /* returns false on error or early cutout of the fold, true if all
2846 * pads in @iter were (de)activated successfully. */
2848 iterator_activate_fold_with_resync (GstIterator * iter,
2849 GstIteratorFoldFunction func, gpointer user_data)
2851 GstIteratorResult ires;
2854 /* no need to unset this later, it's just a boolean */
2855 g_value_init (&ret, G_TYPE_BOOLEAN);
2856 g_value_set_boolean (&ret, TRUE);
2859 ires = gst_iterator_fold (iter, func, &ret, user_data);
2861 case GST_ITERATOR_RESYNC:
2862 /* need to reset the result again */
2863 g_value_set_boolean (&ret, TRUE);
2864 gst_iterator_resync (iter);
2866 case GST_ITERATOR_DONE:
2867 /* all pads iterated, return collected value */
2870 /* iterator returned _ERROR or premature end with _OK,
2871 * mark an error and exit */
2872 g_value_set_boolean (&ret, FALSE);
2877 /* return collected value */
2878 return g_value_get_boolean (&ret);
2881 /* is called with STATE_LOCK
2883 * Pads are activated from source pads to sinkpads.
2886 gst_element_pads_activate (GstElement * element, gboolean active)
2891 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2892 "%s pads", active ? "activate" : "deactivate");
2894 iter = gst_element_iterate_src_pads (element);
2896 iterator_activate_fold_with_resync (iter,
2897 (GstIteratorFoldFunction) activate_pads, &active);
2898 gst_iterator_free (iter);
2899 if (G_UNLIKELY (!res))
2902 iter = gst_element_iterate_sink_pads (element);
2904 iterator_activate_fold_with_resync (iter,
2905 (GstIteratorFoldFunction) activate_pads, &active);
2906 gst_iterator_free (iter);
2907 if (G_UNLIKELY (!res))
2910 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2911 "pad %sactivation successful", active ? "" : "de");
2918 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2919 "pad %sactivation failed", active ? "" : "de");
2924 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2925 "sink pads_activate failed");
2930 /* is called with STATE_LOCK */
2931 static GstStateChangeReturn
2932 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2934 GstState state, next;
2935 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2937 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2939 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2940 next = GST_STATE_TRANSITION_NEXT (transition);
2942 /* if the element already is in the given state, we just return success */
2943 if (next == GST_STATE_VOID_PENDING || state == next)
2946 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2947 "default handler tries setting state from %s to %s (%04x)",
2948 gst_element_state_get_name (state),
2949 gst_element_state_get_name (next), transition);
2951 switch (transition) {
2952 case GST_STATE_CHANGE_NULL_TO_READY:
2954 case GST_STATE_CHANGE_READY_TO_PAUSED:
2955 if (!gst_element_pads_activate (element, TRUE)) {
2956 result = GST_STATE_CHANGE_FAILURE;
2959 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2961 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2963 case GST_STATE_CHANGE_PAUSED_TO_READY:
2964 case GST_STATE_CHANGE_READY_TO_NULL:{
2967 /* deactivate pads in both cases, since they are activated on
2968 ready->paused but the element might not have made it to paused */
2969 if (!gst_element_pads_activate (element, FALSE)) {
2970 result = GST_STATE_CHANGE_FAILURE;
2973 /* Remove all non-persistent contexts */
2974 GST_OBJECT_LOCK (element);
2975 for (l = element->contexts; l;) {
2976 GstContext *context = l->data;
2978 if (!gst_context_is_persistent (context)) {
2981 gst_context_unref (context);
2983 element->contexts = g_list_delete_link (element->contexts, l);
2989 GST_OBJECT_UNLOCK (element);
2993 /* this will catch real but unhandled state changes;
2994 * can only be caused by:
2995 * - a new state was added
2996 * - somehow the element was asked to jump across an intermediate state
2998 g_warning ("Unhandled state change from %s to %s",
2999 gst_element_state_get_name (state),
3000 gst_element_state_get_name (next));
3007 GST_OBJECT_LOCK (element);
3008 result = GST_STATE_RETURN (element);
3009 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3010 "element is already in the %s state",
3011 gst_element_state_get_name (state));
3012 GST_OBJECT_UNLOCK (element);
3019 * gst_element_get_factory:
3020 * @element: a #GstElement to request the element factory of.
3022 * Retrieves the factory that was used to create this element.
3024 * Returns: (transfer none): the #GstElementFactory used for creating this
3025 * element. no refcounting is needed.
3028 gst_element_get_factory (GstElement * element)
3030 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3032 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3036 gst_element_dispose (GObject * object)
3038 GstElement *element = GST_ELEMENT_CAST (object);
3041 GstElementClass *oclass;
3044 oclass = GST_ELEMENT_GET_CLASS (element);
3046 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3048 if (GST_STATE (element) != GST_STATE_NULL)
3051 /* start by releasing all request pads, this might also remove some dynamic
3053 walk = element->pads;
3055 GstPad *pad = GST_PAD_CAST (walk->data);
3059 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3060 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3061 == GST_PAD_REQUEST) {
3062 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3063 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3064 oclass->release_pad (element, pad);
3066 /* in case the release_pad function removed the next pad too */
3067 if (walk && g_list_position (element->pads, walk) == -1)
3068 walk = element->pads;
3071 /* remove the remaining pads */
3072 while (element->pads) {
3073 GstPad *pad = GST_PAD_CAST (element->pads->data);
3074 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3075 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3076 if (!gst_element_remove_pad (element, pad)) {
3077 /* only happens when someone unparented our pad.. */
3078 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3083 GST_OBJECT_LOCK (element);
3084 clock_p = &element->clock;
3085 bus_p = &element->bus;
3086 gst_object_replace ((GstObject **) clock_p, NULL);
3087 gst_object_replace ((GstObject **) bus_p, NULL);
3088 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3089 GST_OBJECT_UNLOCK (element);
3091 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3094 G_OBJECT_CLASS (parent_class)->dispose (object);
3103 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3105 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3107 "You need to explicitly set elements to the NULL state before\n"
3108 "dropping the final reference, to allow them to clean up.\n"
3109 "This problem may also be caused by a refcounting bug in the\n"
3110 "application or some element.\n",
3111 GST_OBJECT_NAME (element),
3112 gst_element_state_get_name (GST_STATE (element)),
3113 is_locked ? " (locked)" : "");
3119 gst_element_finalize (GObject * object)
3121 GstElement *element = GST_ELEMENT_CAST (object);
3123 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3125 g_cond_clear (&element->state_cond);
3126 g_rec_mutex_clear (&element->state_lock);
3128 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3131 G_OBJECT_CLASS (parent_class)->finalize (object);
3135 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3139 g_return_if_fail (GST_IS_ELEMENT (element));
3141 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3143 GST_OBJECT_LOCK (element);
3144 bus_p = &GST_ELEMENT_BUS (element);
3145 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3146 GST_OBJECT_UNLOCK (element);
3150 * gst_element_set_bus:
3151 * @element: a #GstElement to set the bus of.
3152 * @bus: (transfer none): the #GstBus to set.
3154 * Sets the bus of the element. Increases the refcount on the bus.
3155 * For internal use only, unless you're testing elements.
3160 gst_element_set_bus (GstElement * element, GstBus * bus)
3162 GstElementClass *oclass;
3164 g_return_if_fail (GST_IS_ELEMENT (element));
3166 oclass = GST_ELEMENT_GET_CLASS (element);
3168 if (oclass->set_bus)
3169 oclass->set_bus (element, bus);
3173 * gst_element_get_bus:
3174 * @element: a #GstElement to get the bus of.
3176 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3177 * bus for the application.
3179 * Returns: (transfer full): the element's #GstBus. unref after usage.
3184 gst_element_get_bus (GstElement * element)
3186 GstBus *result = NULL;
3188 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3190 GST_OBJECT_LOCK (element);
3191 if ((result = GST_ELEMENT_BUS (element)))
3192 gst_object_ref (result);
3193 GST_OBJECT_UNLOCK (element);
3195 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3202 gst_element_set_context_default (GstElement * element, GstContext * context)
3204 const gchar *context_type;
3207 g_return_if_fail (GST_IS_CONTEXT (context));
3208 context_type = gst_context_get_context_type (context);
3209 g_return_if_fail (context_type != NULL);
3211 GST_OBJECT_LOCK (element);
3212 for (l = element->contexts; l; l = l->next) {
3213 GstContext *tmp = l->data;
3214 const gchar *tmp_type = gst_context_get_context_type (tmp);
3216 /* Always store newest context but never replace
3217 * a persistent one by a non-persistent one */
3218 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3219 (gst_context_is_persistent (context) ||
3220 !gst_context_is_persistent (tmp))) {
3221 gst_context_replace ((GstContext **) & l->data, context);
3225 /* Not found? Add */
3228 g_list_prepend (element->contexts, gst_context_ref (context));
3230 GST_OBJECT_UNLOCK (element);
3234 * gst_element_set_context:
3235 * @element: a #GstElement to set the context of.
3236 * @context: (transfer none): the #GstContext to set.
3238 * Sets the context of the element. Increases the refcount of the context.
3243 gst_element_set_context (GstElement * element, GstContext * context)
3245 GstElementClass *oclass;
3247 g_return_if_fail (GST_IS_ELEMENT (element));
3248 g_return_if_fail (GST_IS_CONTEXT (context));
3250 oclass = GST_ELEMENT_GET_CLASS (element);
3252 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3253 "set context %p %" GST_PTR_FORMAT, context,
3254 gst_context_get_structure (context));
3256 if (oclass->set_context)
3257 oclass->set_context (element, context);
3261 * gst_element_get_contexts:
3262 * @element: a #GstElement to set the context of.
3264 * Gets the contexts set on the element.
3268 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3273 gst_element_get_contexts (GstElement * element)
3277 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3279 GST_OBJECT_LOCK (element);
3280 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3281 GST_OBJECT_UNLOCK (element);
3287 _match_context_type (GstContext * c1, const gchar * context_type)
3289 const gchar *c1_type;
3291 c1_type = gst_context_get_context_type (c1);
3293 return g_strcmp0 (c1_type, context_type);
3297 * gst_element_get_context_unlocked:
3298 * @element: a #GstElement to get the context of.
3299 * @context_type: a name of a context to retrieve
3301 * Gets the context with @context_type set on the element or NULL.
3303 * Returns: (transfer full): A #GstContext or NULL
3308 gst_element_get_context_unlocked (GstElement * element,
3309 const gchar * context_type)
3311 GstContext *ret = NULL;
3314 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3317 g_list_find_custom (element->contexts, context_type,
3318 (GCompareFunc) _match_context_type);
3319 if (node && node->data)
3320 ret = gst_context_ref (node->data);
3326 * gst_element_get_context:
3327 * @element: a #GstElement to get the context of.
3328 * @context_type: a name of a context to retrieve
3330 * Gets the context with @context_type set on the element or NULL.
3334 * Returns: (transfer full): A #GstContext or NULL
3339 gst_element_get_context (GstElement * element, const gchar * context_type)
3341 GstContext *ret = NULL;
3343 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3345 GST_OBJECT_LOCK (element);
3346 ret = gst_element_get_context_unlocked (element, context_type);
3347 GST_OBJECT_UNLOCK (element);
3353 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3354 GParamSpec * pspec, gboolean include_value)
3356 GValue val = G_VALUE_INIT;
3359 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3360 "changed, posting message with%s value", pspec->name, obj,
3361 include_value ? "" : "out");
3363 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3364 g_value_init (&val, pspec->value_type);
3365 g_object_get_property (obj, pspec->name, &val);
3370 gst_element_post_message (element,
3371 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3375 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3376 GParamSpec * pspec, gpointer user_data)
3378 gboolean include_value = GPOINTER_TO_INT (user_data);
3380 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3385 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3388 gboolean include_value = GPOINTER_TO_INT (user_data);
3390 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3395 * gst_element_add_property_notify_watch:
3396 * @element: a #GstElement to watch for property changes
3397 * @property_name: (allow-none): name of property to watch for changes, or
3398 * NULL to watch all properties
3399 * @include_value: whether to include the new property value in the message
3401 * Returns: a watch id, which can be used in connection with
3402 * gst_element_remove_property_notify_watch() to remove the watch again.
3407 gst_element_add_property_notify_watch (GstElement * element,
3408 const gchar * property_name, gboolean include_value)
3414 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3416 sep = (property_name != NULL) ? "::" : NULL;
3417 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3418 id = g_signal_connect (element, signal_name,
3419 G_CALLBACK (gst_element_property_notify_cb),
3420 GINT_TO_POINTER (include_value));
3421 g_free (signal_name);
3427 * gst_element_add_property_deep_notify_watch:
3428 * @element: a #GstElement to watch (recursively) for property changes
3429 * @property_name: (allow-none): name of property to watch for changes, or
3430 * NULL to watch all properties
3431 * @include_value: whether to include the new property value in the message
3433 * Returns: a watch id, which can be used in connection with
3434 * gst_element_remove_property_notify_watch() to remove the watch again.
3439 gst_element_add_property_deep_notify_watch (GstElement * element,
3440 const gchar * property_name, gboolean include_value)
3446 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3448 sep = (property_name != NULL) ? "::" : NULL;
3449 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3450 id = g_signal_connect (element, signal_name,
3451 G_CALLBACK (gst_element_property_deep_notify_cb),
3452 GINT_TO_POINTER (include_value));
3453 g_free (signal_name);
3459 * gst_element_remove_property_notify_watch:
3460 * @element: a #GstElement being watched for property changes
3461 * @watch_id: watch id to remove
3466 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3468 g_signal_handler_disconnect (element, watch_id);
3473 GstElement *element;
3474 GstElementCallAsyncFunc func;
3476 GDestroyNotify destroy_notify;
3477 } GstElementCallAsyncData;
3480 gst_element_call_async_func (gpointer data, gpointer user_data)
3482 GstElementCallAsyncData *async_data = data;
3484 async_data->func (async_data->element, async_data->user_data);
3485 if (async_data->destroy_notify)
3486 async_data->destroy_notify (async_data->user_data);
3487 gst_object_unref (async_data->element);
3488 g_free (async_data);
3492 * gst_element_call_async:
3493 * @element: a #GstElement
3494 * @func: Function to call asynchronously from another thread
3495 * @user_data: Data to pass to @func
3496 * @destroy_notify: GDestroyNotify for @user_data
3498 * Calls @func from another thread and passes @user_data to it. This is to be
3499 * used for cases when a state change has to be performed from a streaming
3500 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3503 * Calling those functions directly from the streaming thread will cause
3504 * deadlocks in many situations, as they might involve waiting for the
3505 * streaming thread to shut down from this very streaming thread.
3512 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3513 gpointer user_data, GDestroyNotify destroy_notify)
3515 GstElementCallAsyncData *async_data;
3517 g_return_if_fail (GST_IS_ELEMENT (element));
3519 async_data = g_new0 (GstElementCallAsyncData, 1);
3520 async_data->element = gst_object_ref (element);
3521 async_data->func = func;
3522 async_data->user_data = user_data;
3523 async_data->destroy_notify = destroy_notify;
3525 g_thread_pool_push (gst_element_pool, async_data, NULL);
3529 _priv_gst_element_cleanup (void)
3531 if (gst_element_pool) {
3532 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3533 gst_element_setup_thread_pool ();
3538 gst_make_element_message_details (const char *name, ...)
3540 GstStructure *structure;
3546 va_start (varargs, name);
3547 structure = gst_structure_new_valist ("details", name, varargs);