2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
26 * @short_description: Abstract base class for all pipeline elements
27 * @see_also: #GstElementFactory, #GstPad
29 * GstElement is the abstract base class needed to construct an element that
30 * can be used in a GStreamer pipeline. Please refer to the plugin writers
31 * guide for more information on creating #GstElement subclasses.
33 * The name of a #GstElement can be get with gst_element_get_name() and set with
34 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
35 * core when using the appropriate locking. Do not use this in plug-ins or
36 * applications in order to retain ABI compatibility.
38 * Elements can have pads (of the type #GstPad). These pads link to pads on
39 * other elements. #GstBuffer flow between these linked pads.
40 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
41 * and output (or source) pads.
42 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
43 * and gst_element_remove_pad().
45 * An existing pad of an element can be retrieved by name with
46 * gst_element_get_static_pad(). A new dynamic pad can be created using
47 * gst_element_request_pad() with a #GstPadTemplate.
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If the
72 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock selection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
80 #include "gst_private.h"
83 #include <gobject/gvaluecollector.h>
85 #include "gstelement.h"
86 #include "gstelementmetadata.h"
87 #include "gstenumtypes.h"
94 #include "gsttracerutils.h"
96 #include "gst-i18n-lib.h"
97 #include "glib-compat-private.h"
99 #ifndef GST_DISABLE_GST_DEBUG
100 #include "printf/printf.h"
103 /* Element signals and args */
119 static void gst_element_class_init (GstElementClass * klass);
120 static void gst_element_init (GstElement * element);
121 static void gst_element_base_class_init (gpointer g_class);
123 static void gst_element_constructed (GObject * object);
124 static void gst_element_dispose (GObject * object);
125 static void gst_element_finalize (GObject * object);
127 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
128 GstStateChange transition);
129 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
130 GstState * state, GstState * pending, GstClockTime timeout);
131 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
133 static gboolean gst_element_set_clock_func (GstElement * element,
135 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
136 static gboolean gst_element_post_message_default (GstElement * element,
137 GstMessage * message);
138 static void gst_element_set_context_default (GstElement * element,
139 GstContext * context);
141 static gboolean gst_element_default_send_event (GstElement * element,
143 static gboolean gst_element_default_query (GstElement * element,
146 static GstPadTemplate
147 * gst_element_class_get_request_pad_template (GstElementClass *
148 element_class, const gchar * name);
150 static void gst_element_call_async_func (gpointer data, gpointer user_data);
152 static GstObjectClass *parent_class = NULL;
153 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
155 static GThreadPool *gst_element_pool = NULL;
157 /* this is used in gstelementfactory.c:gst_element_register() */
158 GQuark __gst_elementclass_factory = 0;
161 gst_element_get_type (void)
163 static volatile gsize gst_element_type = 0;
165 if (g_once_init_enter (&gst_element_type)) {
167 static const GTypeInfo element_info = {
168 sizeof (GstElementClass),
169 gst_element_base_class_init,
170 NULL, /* base_class_finalize */
171 (GClassInitFunc) gst_element_class_init,
176 (GInstanceInitFunc) gst_element_init,
180 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
181 &element_info, G_TYPE_FLAG_ABSTRACT);
183 __gst_elementclass_factory =
184 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
185 g_once_init_leave (&gst_element_type, _type);
187 return gst_element_type;
191 gst_element_setup_thread_pool (void)
195 GST_DEBUG ("creating element thread pool");
197 g_thread_pool_new ((GFunc) gst_element_call_async_func, NULL, -1, FALSE,
200 g_critical ("could not alloc threadpool %s", err->message);
201 g_clear_error (&err);
206 gst_element_class_init (GstElementClass * klass)
208 GObjectClass *gobject_class;
210 gobject_class = (GObjectClass *) klass;
212 parent_class = g_type_class_peek_parent (klass);
215 * GstElement::pad-added:
216 * @gstelement: the object which received the signal
217 * @new_pad: the pad that has been added
219 * a new #GstPad has been added to the element. Note that this signal will
220 * usually be emitted from the context of the streaming thread. Also keep in
221 * mind that if you add new elements to the pipeline in the signal handler
222 * you will need to set them to the desired target state with
223 * gst_element_set_state() or gst_element_sync_state_with_parent().
225 gst_element_signals[PAD_ADDED] =
226 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
227 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
228 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
230 * GstElement::pad-removed:
231 * @gstelement: the object which received the signal
232 * @old_pad: the pad that has been removed
234 * a #GstPad has been removed from the element
236 gst_element_signals[PAD_REMOVED] =
237 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
238 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
239 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
241 * GstElement::no-more-pads:
242 * @gstelement: the object which received the signal
244 * This signals that the element will not generate more dynamic pads.
245 * Note that this signal will usually be emitted from the context of
246 * the streaming thread.
248 gst_element_signals[NO_MORE_PADS] =
249 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
250 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
251 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
253 gobject_class->dispose = gst_element_dispose;
254 gobject_class->finalize = gst_element_finalize;
255 gobject_class->constructed = gst_element_constructed;
257 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
258 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
259 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
260 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
261 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
262 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
263 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
264 klass->numpadtemplates = 0;
265 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
266 klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_default);
268 klass->elementfactory = NULL;
270 gst_element_setup_thread_pool ();
274 gst_element_base_class_init (gpointer g_class)
276 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
277 GList *node, *padtemplates;
279 /* Copy the element details here so elements can inherit the
280 * details from their base class and classes only need to set
281 * the details in class_init instead of base_init */
282 element_class->metadata =
283 element_class->metadata ? gst_structure_copy (element_class->metadata) :
284 gst_structure_new_empty ("metadata");
286 /* Copy the pad templates so elements inherit them
287 * from their base class but elements can add pad templates in class_init
288 * instead of base_init.
290 padtemplates = g_list_copy (element_class->padtemplates);
291 for (node = padtemplates; node != NULL; node = node->next) {
292 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
293 gst_object_ref (tmpl);
295 element_class->padtemplates = padtemplates;
297 /* set the factory, see gst_element_register() */
298 element_class->elementfactory =
299 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
300 __gst_elementclass_factory);
301 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
302 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
306 gst_element_init (GstElement * element)
308 GST_STATE (element) = GST_STATE_NULL;
309 GST_STATE_TARGET (element) = GST_STATE_NULL;
310 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
311 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
312 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
314 g_rec_mutex_init (&element->state_lock);
315 g_cond_init (&element->state_cond);
319 gst_element_constructed (GObject * object)
321 GST_TRACER_ELEMENT_NEW (GST_ELEMENT_CAST (object));
322 G_OBJECT_CLASS (parent_class)->constructed (object);
326 * gst_element_release_request_pad:
327 * @element: a #GstElement to release the request pad of.
328 * @pad: the #GstPad to release.
330 * Makes the element free the previously requested pad as obtained
331 * with gst_element_request_pad().
333 * This does not unref the pad. If the pad was created by using
334 * gst_element_request_pad(), gst_element_release_request_pad() needs to be
335 * followed by gst_object_unref() to free the @pad.
340 gst_element_release_request_pad (GstElement * element, GstPad * pad)
342 GstElementClass *oclass;
344 g_return_if_fail (GST_IS_ELEMENT (element));
345 g_return_if_fail (GST_IS_PAD (pad));
346 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
347 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
349 g_return_if_fail (GST_PAD_PARENT (pad) == element);
351 oclass = GST_ELEMENT_GET_CLASS (element);
353 /* if the element implements a custom release function we call that, else we
354 * simply remove the pad from the element */
355 if (oclass->release_pad)
356 oclass->release_pad (element, pad);
358 gst_element_remove_pad (element, pad);
362 * gst_element_provide_clock:
363 * @element: a #GstElement to query
365 * Get the clock provided by the given element.
366 * > An element is only required to provide a clock in the PAUSED
367 * > state. Some elements can provide a clock in other states.
369 * Returns: (transfer full) (nullable): the GstClock provided by the
370 * element or %NULL if no clock could be provided. Unref after usage.
375 gst_element_provide_clock (GstElement * element)
377 GstClock *result = NULL;
378 GstElementClass *oclass;
380 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
382 oclass = GST_ELEMENT_GET_CLASS (element);
384 if (oclass->provide_clock)
385 result = oclass->provide_clock (element);
391 gst_element_set_clock_func (GstElement * element, GstClock * clock)
395 GST_OBJECT_LOCK (element);
396 clock_p = &element->clock;
397 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
398 GST_OBJECT_UNLOCK (element);
404 * gst_element_set_clock:
405 * @element: a #GstElement to set the clock for.
406 * @clock: the #GstClock to set for the element.
408 * Sets the clock for the element. This function increases the
409 * refcount on the clock. Any previously set clock on the object
412 * Returns: %TRUE if the element accepted the clock. An element can refuse a
413 * clock when it, for example, is not able to slave its internal clock to the
414 * @clock or when it requires a specific clock to operate.
419 gst_element_set_clock (GstElement * element, GstClock * clock)
421 GstElementClass *oclass;
422 gboolean res = FALSE;
424 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
425 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
427 oclass = GST_ELEMENT_GET_CLASS (element);
429 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
431 if (oclass->set_clock)
432 res = oclass->set_clock (element, clock);
438 * gst_element_get_clock:
439 * @element: a #GstElement to get the clock of.
441 * Gets the currently configured clock of the element. This is the clock as was
442 * last set with gst_element_set_clock().
444 * Elements in a pipeline will only have their clock set when the
445 * pipeline is in the PLAYING state.
447 * Returns: (transfer full): the #GstClock of the element. unref after usage.
452 gst_element_get_clock (GstElement * element)
456 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
458 GST_OBJECT_LOCK (element);
459 if ((result = element->clock))
460 gst_object_ref (result);
461 GST_OBJECT_UNLOCK (element);
467 * gst_element_set_base_time:
468 * @element: a #GstElement.
469 * @time: the base time to set.
471 * Set the base time of an element. See gst_element_get_base_time().
476 gst_element_set_base_time (GstElement * element, GstClockTime time)
480 g_return_if_fail (GST_IS_ELEMENT (element));
482 GST_OBJECT_LOCK (element);
483 old = element->base_time;
484 element->base_time = time;
485 GST_OBJECT_UNLOCK (element);
487 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
488 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
489 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
493 * gst_element_get_base_time:
494 * @element: a #GstElement.
496 * Returns the base time of the element. The base time is the
497 * absolute time of the clock when this element was last put to
498 * PLAYING. Subtracting the base time from the clock time gives
499 * the running time of the element.
501 * Returns: the base time of the element.
506 gst_element_get_base_time (GstElement * element)
510 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
512 GST_OBJECT_LOCK (element);
513 result = element->base_time;
514 GST_OBJECT_UNLOCK (element);
520 * gst_element_set_start_time:
521 * @element: a #GstElement.
522 * @time: the base time to set.
524 * Set the start time of an element. The start time of the element is the
525 * running time of the element when it last went to the PAUSED state. In READY
526 * or after a flushing seek, it is set to 0.
528 * Toplevel elements like #GstPipeline will manage the start_time and
529 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
530 * on such a toplevel element will disable the distribution of the base_time to
531 * the children and can be useful if the application manages the base_time
532 * itself, for example if you want to synchronize capture from multiple
533 * pipelines, and you can also ensure that the pipelines have the same clock.
538 gst_element_set_start_time (GstElement * element, GstClockTime time)
542 g_return_if_fail (GST_IS_ELEMENT (element));
544 GST_OBJECT_LOCK (element);
545 old = GST_ELEMENT_START_TIME (element);
546 GST_ELEMENT_START_TIME (element) = time;
547 GST_OBJECT_UNLOCK (element);
549 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
550 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
551 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
555 * gst_element_get_start_time:
556 * @element: a #GstElement.
558 * Returns the start time of the element. The start time is the
559 * running time of the clock when this element was last put to PAUSED.
561 * Usually the start_time is managed by a toplevel element such as
566 * Returns: the start time of the element.
569 gst_element_get_start_time (GstElement * element)
573 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
575 GST_OBJECT_LOCK (element);
576 result = GST_ELEMENT_START_TIME (element);
577 GST_OBJECT_UNLOCK (element);
584 * gst_element_set_index:
585 * @element: a #GstElement.
586 * @index: (transfer none): a #GstIndex.
588 * Set @index on the element. The refcount of the index
589 * will be increased, any previously set index is unreffed.
594 gst_element_set_index (GstElement * element, GstIndex * index)
596 GstElementClass *oclass;
598 g_return_if_fail (GST_IS_ELEMENT (element));
599 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
601 oclass = GST_ELEMENT_GET_CLASS (element);
603 if (oclass->set_index)
604 oclass->set_index (element, index);
608 * gst_element_get_index:
609 * @element: a #GstElement.
611 * Gets the index from the element.
613 * Returns: (transfer full) (nullable): a #GstIndex or %NULL when no
614 * index was set on the element. unref after usage.
619 gst_element_get_index (GstElement * element)
621 GstElementClass *oclass;
622 GstIndex *result = NULL;
624 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
626 oclass = GST_ELEMENT_GET_CLASS (element);
628 if (oclass->get_index)
629 result = oclass->get_index (element);
636 * gst_element_add_pad:
637 * @element: a #GstElement to add the pad to.
638 * @pad: (transfer floating): the #GstPad to add to the element.
640 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
641 * see gst_object_set_parent() for refcounting information.
643 * Pads are not automatically activated so elements should perform the needed
644 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
645 * state. See gst_pad_set_active() for more information about activating pads.
647 * The pad and the element should be unlocked when calling this function.
649 * This function will emit the #GstElement::pad-added signal on the element.
651 * Returns: %TRUE if the pad could be added. This function can fail when
652 * a pad with the same name already existed or the pad already had another
658 gst_element_add_pad (GstElement * element, GstPad * pad)
663 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
664 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
666 /* locking pad to look at the name */
667 GST_OBJECT_LOCK (pad);
668 pad_name = g_strdup (GST_PAD_NAME (pad));
669 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
670 GST_STR_NULL (pad_name));
671 active = GST_PAD_IS_ACTIVE (pad);
672 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
673 GST_OBJECT_UNLOCK (pad);
675 /* then check to see if there's already a pad by that name here */
676 GST_OBJECT_LOCK (element);
677 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
680 /* try to set the pad's parent */
681 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
682 GST_OBJECT_CAST (element))))
685 /* check for active pads */
686 if (!active && (GST_STATE (element) > GST_STATE_READY ||
687 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
688 g_warning ("adding inactive pad '%s' to running element '%s', you need to "
689 "use gst_pad_set_active(pad,TRUE) before adding it.",
690 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
691 gst_pad_set_active (pad, TRUE);
696 /* add it to the list */
697 switch (gst_pad_get_direction (pad)) {
699 element->srcpads = g_list_append (element->srcpads, pad);
700 element->numsrcpads++;
703 element->sinkpads = g_list_append (element->sinkpads, pad);
704 element->numsinkpads++;
709 element->pads = g_list_append (element->pads, pad);
711 element->pads_cookie++;
712 GST_OBJECT_UNLOCK (element);
714 /* emit the PAD_ADDED signal */
715 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
716 GST_TRACER_ELEMENT_ADD_PAD (element, pad);
722 g_critical ("Padname %s is not unique in element %s, not adding",
723 pad_name, GST_ELEMENT_NAME (element));
724 GST_OBJECT_UNLOCK (element);
726 gst_object_ref_sink (pad);
727 gst_object_unref (pad);
733 ("Pad %s already has parent when trying to add to element %s",
734 pad_name, GST_ELEMENT_NAME (element));
735 GST_OBJECT_UNLOCK (element);
741 GST_OBJECT_LOCK (pad);
743 ("Trying to add pad %s to element %s, but it has no direction",
744 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
745 GST_OBJECT_UNLOCK (pad);
746 GST_OBJECT_UNLOCK (element);
752 * gst_element_remove_pad:
753 * @element: a #GstElement to remove pad from.
754 * @pad: (transfer full): the #GstPad to remove from the element.
756 * Removes @pad from @element. @pad will be destroyed if it has not been
757 * referenced elsewhere using gst_object_unparent().
759 * This function is used by plugin developers and should not be used
760 * by applications. Pads that were dynamically requested from elements
761 * with gst_element_request_pad() should be released with the
762 * gst_element_release_request_pad() function instead.
764 * Pads are not automatically deactivated so elements should perform the needed
765 * steps to deactivate the pad in case this pad is removed in the PAUSED or
766 * PLAYING state. See gst_pad_set_active() for more information about
769 * The pad and the element should be unlocked when calling this function.
771 * This function will emit the #GstElement::pad-removed signal on the element.
773 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
774 * pad does not belong to the provided element.
779 gst_element_remove_pad (GstElement * element, GstPad * pad)
783 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
784 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
786 /* locking pad to look at the name and parent */
787 GST_OBJECT_LOCK (pad);
788 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
789 GST_STR_NULL (GST_PAD_NAME (pad)));
791 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
793 GST_OBJECT_UNLOCK (pad);
796 if ((peer = gst_pad_get_peer (pad))) {
797 /* window for MT unsafeness, someone else could unlink here
798 * and then we call unlink with wrong pads. The unlink
799 * function would catch this and safely return failed. */
800 if (GST_PAD_IS_SRC (pad))
801 gst_pad_unlink (pad, peer);
803 gst_pad_unlink (peer, pad);
805 gst_object_unref (peer);
808 GST_OBJECT_LOCK (element);
809 /* remove it from the list */
810 switch (gst_pad_get_direction (pad)) {
812 element->srcpads = g_list_remove (element->srcpads, pad);
813 element->numsrcpads--;
816 element->sinkpads = g_list_remove (element->sinkpads, pad);
817 element->numsinkpads--;
820 g_critical ("Removing pad without direction???");
823 element->pads = g_list_remove (element->pads, pad);
825 element->pads_cookie++;
826 GST_OBJECT_UNLOCK (element);
828 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
829 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
830 GST_TRACER_ELEMENT_REMOVE_PAD (element, pad);
831 gst_object_unparent (GST_OBJECT_CAST (pad));
838 /* locking order is element > pad */
839 GST_OBJECT_UNLOCK (pad);
841 GST_OBJECT_LOCK (element);
842 GST_OBJECT_LOCK (pad);
843 g_critical ("Padname %s:%s does not belong to element %s when removing",
844 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
845 GST_OBJECT_UNLOCK (pad);
846 GST_OBJECT_UNLOCK (element);
852 * gst_element_no_more_pads:
853 * @element: a #GstElement
855 * Use this function to signal that the element does not expect any more pads
856 * to show up in the current pipeline. This function should be called whenever
857 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
858 * pad templates use this in combination with autopluggers to figure out that
859 * the element is done initializing its pads.
861 * This function emits the #GstElement::no-more-pads signal.
866 gst_element_no_more_pads (GstElement * element)
868 g_return_if_fail (GST_IS_ELEMENT (element));
870 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
874 pad_compare_name (GstPad * pad1, const gchar * name)
878 GST_OBJECT_LOCK (pad1);
879 result = strcmp (GST_PAD_NAME (pad1), name);
880 GST_OBJECT_UNLOCK (pad1);
886 * gst_element_get_static_pad:
887 * @element: a #GstElement to find a static pad of.
888 * @name: the name of the static #GstPad to retrieve.
890 * Retrieves a pad from @element by name. This version only retrieves
891 * already-existing (i.e. 'static') pads.
893 * Returns: (transfer full) (nullable): the requested #GstPad if
894 * found, otherwise %NULL. unref after usage.
899 gst_element_get_static_pad (GstElement * element, const gchar * name)
902 GstPad *result = NULL;
904 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
905 g_return_val_if_fail (name != NULL, NULL);
907 GST_OBJECT_LOCK (element);
909 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
911 result = GST_PAD_CAST (find->data);
912 gst_object_ref (result);
915 if (result == NULL) {
916 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
917 name, GST_ELEMENT_NAME (element));
919 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
920 GST_ELEMENT_NAME (element), name);
922 GST_OBJECT_UNLOCK (element);
928 gst_element_is_valid_request_template_name (const gchar * templ_name,
932 const gchar *templ_name_ptr, *name_ptr;
933 gboolean next_specifier;
934 guint templ_postfix_len = 0, name_postfix_len = 0;
936 g_return_val_if_fail (templ_name != NULL, FALSE);
937 g_return_val_if_fail (name != NULL, FALSE);
939 /* Is this the template name? */
940 if (strcmp (templ_name, name) == 0)
943 /* otherwise check all the specifiers */
945 /* Because of sanity checks in gst_pad_template_new(), we know that %s
946 * and %d and %u, occurring at the template_name */
947 templ_name_ptr = strchr (templ_name, '%');
949 /* check characters ahead of the specifier */
950 if (!templ_name_ptr || strlen (name) <= templ_name_ptr - templ_name
951 || strncmp (templ_name, name, templ_name_ptr - templ_name) != 0) {
955 /* %s is not allowed for multiple specifiers, just a single specifier can be
956 * accepted in gst_pad_template_new() and can not be mixed with other
957 * specifier '%u' and '%d' */
958 if (*(templ_name_ptr + 1) == 's' && g_strcmp0 (templ_name, name) == 0) {
962 name_ptr = name + (templ_name_ptr - templ_name);
964 /* search next specifier, each of specifier should be separated by '_' */
965 templ_name = strchr (templ_name_ptr, '_');
966 name = strchr (name_ptr, '_');
968 /* don't match the number of specifiers */
969 if ((templ_name && !name) || (!templ_name && name))
972 if (templ_name && name)
973 next_specifier = TRUE;
975 next_specifier = FALSE;
977 /* check characters followed by the specifier */
978 if (*(templ_name_ptr + 2) != '\0' && *(templ_name_ptr + 2) != '_') {
979 if (next_specifier) {
980 templ_postfix_len = templ_name - (templ_name_ptr + 2);
981 name_postfix_len = name - name_ptr;
983 templ_postfix_len = strlen (templ_name_ptr + 2);
984 name_postfix_len = strlen (name_ptr);
987 if (strncmp (templ_name_ptr + 2,
988 name_ptr + name_postfix_len - templ_postfix_len,
989 templ_postfix_len) != 0) {
994 /* verify the specifier */
995 if (*(name_ptr) == '%') {
998 len = (next_specifier) ? name - name_ptr : strlen (name_ptr);
1000 if (strncmp (name_ptr, templ_name_ptr, len) != 0)
1004 const gchar *specifier;
1005 gchar *target = NULL;
1007 /* extract specifier when it has postfix characters */
1008 if (name_postfix_len > templ_postfix_len) {
1009 target = g_strndup (name_ptr, name_postfix_len - templ_postfix_len);
1011 specifier = target ? target : name_ptr;
1013 if (*(templ_name_ptr + 1) == 'd') {
1017 tmp = g_ascii_strtoll (specifier, &endptr, 10);
1018 if (tmp < G_MININT || tmp > G_MAXINT || (*endptr != '\0'
1021 } else if (*(templ_name_ptr + 1) == 'u') {
1025 tmp = g_ascii_strtoull (specifier, &endptr, 10);
1026 if (tmp > G_MAXUINT || (*endptr != '\0' && *endptr != '_'))
1033 /* otherwise we increment these from NULL to 1 */
1034 if (next_specifier) {
1038 } while (next_specifier);
1044 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
1045 const gchar * name, const GstCaps * caps)
1047 GstPad *newpad = NULL;
1048 GstElementClass *oclass;
1050 oclass = GST_ELEMENT_GET_CLASS (element);
1052 #ifndef G_DISABLE_CHECKS
1053 /* Some sanity checking here */
1057 g_return_val_if_fail (gst_element_is_valid_request_template_name
1058 (templ->name_template, name), NULL);
1060 pad = gst_element_get_static_pad (element, name);
1062 gst_object_unref (pad);
1063 /* FIXME 2.0: Change this to g_return_val_if_fail() */
1064 g_critical ("Element %s already has a pad named %s, the behaviour of "
1065 " gst_element_get_request_pad() for existing pads is undefined!",
1066 GST_ELEMENT_NAME (element), name);
1071 if (oclass->request_new_pad)
1072 newpad = (oclass->request_new_pad) (element, templ, name, caps);
1075 gst_object_ref (newpad);
1081 * gst_element_get_request_pad:
1082 * @element: a #GstElement to find a request pad of.
1083 * @name: the name of the request #GstPad to retrieve.
1085 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
1086 * retrieves request pads. The pad should be released with
1087 * gst_element_release_request_pad().
1089 * This method is slower than manually getting the pad template and calling
1090 * gst_element_request_pad() if the pads should have a specific name (e.g.
1091 * @name is "src_1" instead of "src_\%u").
1093 * Returns: (transfer full) (nullable): requested #GstPad if found,
1094 * otherwise %NULL. Release after usage.
1097 gst_element_get_request_pad (GstElement * element, const gchar * name)
1099 GstPadTemplate *templ = NULL;
1101 const gchar *req_name = NULL;
1102 gboolean templ_found = FALSE;
1104 GstElementClass *class;
1106 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1107 g_return_val_if_fail (name != NULL, NULL);
1109 class = GST_ELEMENT_GET_CLASS (element);
1111 templ = gst_element_class_get_request_pad_template (class, name);
1113 req_name = strstr (name, "%") ? NULL : name;
1116 /* there is no % in the name, try to find a matching template */
1117 list = class->padtemplates;
1118 while (!templ_found && list) {
1119 templ = (GstPadTemplate *) list->data;
1120 if (templ->presence == GST_PAD_REQUEST) {
1121 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1122 templ->name_template);
1123 if (gst_element_is_valid_request_template_name (templ->name_template,
1137 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1143 * gst_element_request_pad: (virtual request_new_pad)
1144 * @element: a #GstElement to find a request pad of.
1145 * @templ: a #GstPadTemplate of which we want a pad of.
1146 * @name: (transfer none) (allow-none): the name of the request #GstPad
1147 * to retrieve. Can be %NULL.
1148 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1149 * request. Can be %NULL.
1151 * Retrieves a request pad from the element according to the provided template.
1152 * Pad templates can be looked up using
1153 * gst_element_factory_get_static_pad_templates().
1155 * The pad should be released with gst_element_release_request_pad().
1157 * Returns: (transfer full) (nullable): requested #GstPad if found,
1158 * otherwise %NULL. Release after usage.
1161 gst_element_request_pad (GstElement * element,
1162 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1164 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1165 g_return_val_if_fail (templ != NULL, NULL);
1166 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1168 return _gst_element_request_pad (element, templ, name, caps);
1171 static GstIterator *
1172 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1174 GstIterator *result;
1176 GST_OBJECT_LOCK (element);
1177 result = gst_iterator_new_list (GST_TYPE_PAD,
1178 GST_OBJECT_GET_LOCK (element),
1179 &element->pads_cookie, padlist, (GObject *) element, NULL);
1180 GST_OBJECT_UNLOCK (element);
1186 * gst_element_iterate_pads:
1187 * @element: a #GstElement to iterate pads of.
1189 * Retrieves an iterator of @element's pads. The iterator should
1190 * be freed after usage. Also more specialized iterators exists such as
1191 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1193 * The order of pads returned by the iterator will be the order in which
1194 * the pads were added to the element.
1196 * Returns: (transfer full): the #GstIterator of #GstPad.
1201 gst_element_iterate_pads (GstElement * element)
1203 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1205 return gst_element_iterate_pad_list (element, &element->pads);
1209 * gst_element_iterate_src_pads:
1210 * @element: a #GstElement.
1212 * Retrieves an iterator of @element's source pads.
1214 * The order of pads returned by the iterator will be the order in which
1215 * the pads were added to the element.
1217 * Returns: (transfer full): the #GstIterator of #GstPad.
1222 gst_element_iterate_src_pads (GstElement * element)
1224 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1226 return gst_element_iterate_pad_list (element, &element->srcpads);
1230 * gst_element_iterate_sink_pads:
1231 * @element: a #GstElement.
1233 * Retrieves an iterator of @element's sink pads.
1235 * The order of pads returned by the iterator will be the order in which
1236 * the pads were added to the element.
1238 * Returns: (transfer full): the #GstIterator of #GstPad.
1243 gst_element_iterate_sink_pads (GstElement * element)
1245 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1247 return gst_element_iterate_pad_list (element, &element->sinkpads);
1251 * gst_element_class_add_pad_template:
1252 * @klass: the #GstElementClass to add the pad template to.
1253 * @templ: (transfer floating): a #GstPadTemplate to add to the element class.
1255 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1256 * functions of classes. If a pad template with the same name as an already
1257 * existing one is added the old one is replaced by the new one.
1259 * @templ's reference count will be incremented, and any floating
1260 * reference will be removed (see gst_object_ref_sink())
1264 gst_element_class_add_pad_template (GstElementClass * klass,
1265 GstPadTemplate * templ)
1267 GList *template_list = klass->padtemplates;
1269 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1270 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1272 /* If we already have a pad template with the same name replace the
1274 while (template_list) {
1275 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1277 /* Found pad with the same name, replace and return */
1278 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1279 gst_object_ref_sink (padtempl);
1280 gst_object_unref (padtempl);
1281 template_list->data = templ;
1284 template_list = g_list_next (template_list);
1287 /* Take ownership of the floating ref */
1288 gst_object_ref_sink (templ);
1290 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1291 klass->numpadtemplates++;
1295 * gst_element_class_add_static_pad_template:
1296 * @klass: the #GstElementClass to add the pad template to.
1297 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1299 * Adds a pad template to an element class based on the static pad template
1300 * @templ. This is mainly used in the _class_init functions of element
1301 * implementations. If a pad template with the same name already exists,
1302 * the old one is replaced by the new one.
1307 gst_element_class_add_static_pad_template (GstElementClass * klass,
1308 GstStaticPadTemplate * static_templ)
1310 gst_element_class_add_pad_template (klass,
1311 gst_static_pad_template_get (static_templ));
1315 * gst_element_class_add_metadata:
1316 * @klass: class to set metadata for
1317 * @key: the key to set
1318 * @value: the value to set
1320 * Set @key with @value as metadata in @klass.
1323 gst_element_class_add_metadata (GstElementClass * klass,
1324 const gchar * key, const gchar * value)
1326 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1327 g_return_if_fail (key != NULL);
1328 g_return_if_fail (value != NULL);
1330 gst_structure_set ((GstStructure *) klass->metadata,
1331 key, G_TYPE_STRING, value, NULL);
1335 * gst_element_class_add_static_metadata:
1336 * @klass: class to set metadata for
1337 * @key: the key to set
1338 * @value: the value to set
1340 * Set @key with @value as metadata in @klass.
1342 * Same as gst_element_class_add_metadata(), but @value must be a static string
1343 * or an inlined string, as it will not be copied. (GStreamer plugins will
1344 * be made resident once loaded, so this function can be used even from
1345 * dynamically loaded plugins.)
1348 gst_element_class_add_static_metadata (GstElementClass * klass,
1349 const gchar * key, const gchar * value)
1351 GValue val = G_VALUE_INIT;
1353 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1354 g_return_if_fail (key != NULL);
1355 g_return_if_fail (value != NULL);
1357 g_value_init (&val, G_TYPE_STRING);
1358 g_value_set_static_string (&val, value);
1359 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1363 * gst_element_class_set_metadata:
1364 * @klass: class to set metadata for
1365 * @longname: The long English name of the element. E.g. "File Sink"
1366 * @classification: String describing the type of element, as an unordered list
1367 * separated with slashes ('/'). See draft-klass.txt of the design docs
1368 * for more details and common types. E.g: "Sink/File"
1369 * @description: Sentence describing the purpose of the element.
1370 * E.g: "Write stream to a file"
1371 * @author: Name and contact details of the author(s). Use \n to separate
1372 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1374 * Sets the detailed information for a #GstElementClass.
1375 * > This function is for use in _class_init functions only.
1378 gst_element_class_set_metadata (GstElementClass * klass,
1379 const gchar * longname, const gchar * classification,
1380 const gchar * description, const gchar * author)
1382 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1383 g_return_if_fail (longname != NULL && *longname != '\0');
1384 g_return_if_fail (classification != NULL && *classification != '\0');
1385 g_return_if_fail (description != NULL && *description != '\0');
1386 g_return_if_fail (author != NULL && *author != '\0');
1388 gst_structure_id_set ((GstStructure *) klass->metadata,
1389 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1390 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1391 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1392 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1396 * gst_element_class_set_static_metadata:
1397 * @klass: class to set metadata for
1398 * @longname: The long English name of the element. E.g. "File Sink"
1399 * @classification: String describing the type of element, as an unordered list
1400 * separated with slashes ('/'). See draft-klass.txt of the design docs
1401 * for more details and common types. E.g: "Sink/File"
1402 * @description: Sentence describing the purpose of the element.
1403 * E.g: "Write stream to a file"
1404 * @author: Name and contact details of the author(s). Use \n to separate
1405 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1407 * Sets the detailed information for a #GstElementClass.
1409 * > This function is for use in _class_init functions only.
1411 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1412 * @description, and @author must be static strings or inlined strings, as
1413 * they will not be copied. (GStreamer plugins will be made resident once
1414 * loaded, so this function can be used even from dynamically loaded plugins.)
1417 gst_element_class_set_static_metadata (GstElementClass * klass,
1418 const gchar * longname, const gchar * classification,
1419 const gchar * description, const gchar * author)
1421 GstStructure *s = (GstStructure *) klass->metadata;
1422 GValue val = G_VALUE_INIT;
1424 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1425 g_return_if_fail (longname != NULL && *longname != '\0');
1426 g_return_if_fail (classification != NULL && *classification != '\0');
1427 g_return_if_fail (description != NULL && *description != '\0');
1428 g_return_if_fail (author != NULL && *author != '\0');
1430 g_value_init (&val, G_TYPE_STRING);
1432 g_value_set_static_string (&val, longname);
1433 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1435 g_value_set_static_string (&val, classification);
1436 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1438 g_value_set_static_string (&val, description);
1439 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1442 g_value_set_static_string (&val, author);
1443 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1447 * gst_element_class_get_metadata:
1448 * @klass: class to get metadata for
1449 * @key: the key to get
1451 * Get metadata with @key in @klass.
1453 * Returns: the metadata for @key.
1456 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1458 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1459 g_return_val_if_fail (key != NULL, NULL);
1461 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1465 * gst_element_class_get_pad_template_list:
1466 * @element_class: a #GstElementClass to get pad templates of.
1468 * Retrieves a list of the pad templates associated with @element_class. The
1469 * list must not be modified by the calling code.
1470 * > If you use this function in the #GInstanceInitFunc of an object class
1471 * > that has subclasses, make sure to pass the g_class parameter of the
1472 * > #GInstanceInitFunc here.
1474 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1478 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1480 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1482 return element_class->padtemplates;
1486 * gst_element_class_get_pad_template:
1487 * @element_class: a #GstElementClass to get the pad template of.
1488 * @name: the name of the #GstPadTemplate to get.
1490 * Retrieves a padtemplate from @element_class with the given name.
1491 * > If you use this function in the #GInstanceInitFunc of an object class
1492 * > that has subclasses, make sure to pass the g_class parameter of the
1493 * > #GInstanceInitFunc here.
1495 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1496 * given name, or %NULL if none was found. No unreferencing is
1500 gst_element_class_get_pad_template (GstElementClass *
1501 element_class, const gchar * name)
1505 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1506 g_return_val_if_fail (name != NULL, NULL);
1508 padlist = element_class->padtemplates;
1511 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1513 if (strcmp (padtempl->name_template, name) == 0)
1516 padlist = g_list_next (padlist);
1522 static GstPadTemplate *
1523 gst_element_class_get_request_pad_template (GstElementClass *
1524 element_class, const gchar * name)
1526 GstPadTemplate *tmpl;
1528 tmpl = gst_element_class_get_pad_template (element_class, name);
1529 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1535 /* get a random pad on element of the given direction.
1536 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1539 gst_element_get_random_pad (GstElement * element,
1540 gboolean need_linked, GstPadDirection dir)
1542 GstPad *result = NULL;
1545 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1549 GST_OBJECT_LOCK (element);
1550 pads = element->srcpads;
1553 GST_OBJECT_LOCK (element);
1554 pads = element->sinkpads;
1557 goto wrong_direction;
1559 for (; pads; pads = g_list_next (pads)) {
1560 GstPad *pad = GST_PAD_CAST (pads->data);
1562 GST_OBJECT_LOCK (pad);
1563 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1564 GST_DEBUG_PAD_NAME (pad));
1566 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1567 /* if we require a linked pad, and it is not linked, continue the
1569 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1570 GST_DEBUG_PAD_NAME (pad));
1571 GST_OBJECT_UNLOCK (pad);
1574 /* found a pad, stop search */
1575 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1576 GST_DEBUG_PAD_NAME (pad));
1577 GST_OBJECT_UNLOCK (pad);
1583 gst_object_ref (result);
1585 GST_OBJECT_UNLOCK (element);
1589 /* ERROR handling */
1592 g_warning ("unknown pad direction %d", dir);
1598 gst_element_default_send_event (GstElement * element, GstEvent * event)
1600 gboolean result = FALSE;
1603 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1604 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1605 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1608 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1609 "pushing %s event to random %s pad %s:%s",
1610 GST_EVENT_TYPE_NAME (event),
1611 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1612 GST_DEBUG_PAD_NAME (pad));
1614 result = gst_pad_send_event (pad, event);
1615 gst_object_unref (pad);
1617 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1618 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1619 gst_event_unref (event);
1625 * gst_element_send_event:
1626 * @element: a #GstElement to send the event to.
1627 * @event: (transfer full): the #GstEvent to send to the element.
1629 * Sends an event to an element. If the element doesn't implement an
1630 * event handler, the event will be pushed on a random linked sink pad for
1631 * downstream events or a random linked source pad for upstream events.
1633 * This function takes ownership of the provided event so you should
1634 * gst_event_ref() it if you want to reuse the event after this call.
1638 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1639 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1642 gst_element_send_event (GstElement * element, GstEvent * event)
1644 GstElementClass *oclass;
1645 gboolean result = FALSE;
1647 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1648 g_return_val_if_fail (event != NULL, FALSE);
1650 oclass = GST_ELEMENT_GET_CLASS (element);
1652 GST_STATE_LOCK (element);
1653 if (oclass->send_event) {
1654 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1655 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1656 result = oclass->send_event (element, event);
1658 gst_event_unref (event);
1660 GST_STATE_UNLOCK (element);
1667 * @element: a #GstElement to send the event to.
1668 * @rate: The new playback rate
1669 * @format: The format of the seek values
1670 * @flags: The optional seek flags.
1671 * @start_type: The type and flags for the new start position
1672 * @start: The value of the new start position
1673 * @stop_type: The type and flags for the new stop position
1674 * @stop: The value of the new stop position
1676 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1677 * the parameters. The seek event is sent to the element using
1678 * gst_element_send_event().
1682 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1683 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1686 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1687 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1688 GstSeekType stop_type, gint64 stop)
1693 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1696 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1698 result = gst_element_send_event (element, event);
1704 gst_element_default_query (GstElement * element, GstQuery * query)
1706 gboolean result = FALSE;
1709 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1711 result = gst_pad_query (pad, query);
1713 gst_object_unref (pad);
1715 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1717 GstPad *peer = gst_pad_get_peer (pad);
1720 result = gst_pad_query (peer, query);
1722 gst_object_unref (peer);
1724 gst_object_unref (pad);
1731 * gst_element_query:
1732 * @element: a #GstElement to perform the query on.
1733 * @query: (transfer none): the #GstQuery.
1735 * Performs a query on the given element.
1737 * For elements that don't implement a query handler, this function
1738 * forwards the query to a random srcpad or to the peer of a
1739 * random linked sinkpad of this element.
1741 * Please note that some queries might need a running pipeline to work.
1743 * Returns: %TRUE if the query could be performed.
1748 gst_element_query (GstElement * element, GstQuery * query)
1750 GstElementClass *klass;
1751 gboolean res = FALSE;
1753 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1754 g_return_val_if_fail (query != NULL, FALSE);
1756 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1758 klass = GST_ELEMENT_GET_CLASS (element);
1760 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1761 GST_ELEMENT_NAME (element));
1762 res = klass->query (element, query);
1765 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1770 gst_element_post_message_default (GstElement * element, GstMessage * message)
1773 gboolean result = FALSE;
1775 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1776 g_return_val_if_fail (message != NULL, FALSE);
1778 GST_OBJECT_LOCK (element);
1781 if (G_UNLIKELY (bus == NULL))
1784 gst_object_ref (bus);
1785 GST_OBJECT_UNLOCK (element);
1787 /* we release the element lock when posting the message so that any
1788 * (synchronous) message handlers can operate on the element */
1789 result = gst_bus_post (bus, message);
1790 gst_object_unref (bus);
1797 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1798 "not posting message %p: no bus", message);
1799 GST_OBJECT_UNLOCK (element);
1800 gst_message_unref (message);
1806 * gst_element_post_message:
1807 * @element: a #GstElement posting the message
1808 * @message: (transfer full): a #GstMessage to post
1810 * Post a message on the element's #GstBus. This function takes ownership of the
1811 * message; if you want to access the message after this call, you should add an
1812 * additional reference before calling.
1814 * Returns: %TRUE if the message was successfully posted. The function returns
1815 * %FALSE if the element did not have a bus.
1820 gst_element_post_message (GstElement * element, GstMessage * message)
1822 GstElementClass *klass;
1823 gboolean res = FALSE;
1825 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1826 g_return_val_if_fail (message != NULL, FALSE);
1828 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1830 klass = GST_ELEMENT_GET_CLASS (element);
1831 if (klass->post_message)
1832 res = klass->post_message (element, message);
1834 gst_message_unref (message);
1836 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1841 * _gst_element_error_printf:
1842 * @format: (allow-none): the printf-like format to use, or %NULL
1844 * This function is only used internally by the gst_element_error() macro.
1846 * Returns: (transfer full) (nullable): a newly allocated string, or
1847 * %NULL if the format was %NULL or ""
1852 _gst_element_error_printf (const gchar * format, ...)
1863 va_start (args, format);
1865 len = __gst_vasprintf (&buffer, format, args);
1876 * gst_element_message_full_with_details:
1877 * @element: a #GstElement to send message from
1878 * @type: the #GstMessageType
1879 * @domain: the GStreamer GError domain this message belongs to
1880 * @code: the GError code belonging to the domain
1881 * @text: (allow-none) (transfer full): an allocated text string to be used
1882 * as a replacement for the default message connected to code,
1884 * @debug: (allow-none) (transfer full): an allocated debug message to be
1885 * used as a replacement for the default debugging information,
1887 * @file: the source code file where the error was generated
1888 * @function: the source code function where the error was generated
1889 * @line: the source code line where the error was generated
1890 * @structure:(transfer full): optional details structure
1892 * Post an error, warning or info message on the bus from inside an element.
1894 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1895 * #GST_MESSAGE_INFO.
1899 void gst_element_message_full_with_details
1900 (GstElement * element, GstMessageType type,
1901 GQuark domain, gint code, gchar * text,
1902 gchar * debug, const gchar * file, const gchar * function, gint line,
1903 GstStructure * structure)
1905 GError *gerror = NULL;
1909 gboolean has_debug = TRUE;
1910 GstMessage *message = NULL;
1913 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1914 g_return_if_fail (GST_IS_ELEMENT (element));
1915 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1916 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1918 /* check if we send the given text or the default error text */
1919 if ((text == NULL) || (text[0] == 0)) {
1920 /* text could have come from g_strdup_printf (""); */
1922 sent_text = gst_error_get_message (domain, code);
1926 /* construct a sent_debug with extra information from source */
1927 if ((debug == NULL) || (debug[0] == 0)) {
1928 /* debug could have come from g_strdup_printf (""); */
1932 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1934 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1935 file, line, function, name, debug);
1937 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1938 file, line, function, name);
1942 /* create gerror and post message */
1943 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1945 gerror = g_error_new_literal (domain, code, sent_text);
1948 case GST_MESSAGE_ERROR:
1950 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1951 sent_debug, structure);
1953 case GST_MESSAGE_WARNING:
1955 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1956 gerror, sent_debug, structure);
1958 case GST_MESSAGE_INFO:
1960 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1961 sent_debug, structure);
1964 g_assert_not_reached ();
1968 gst_element_post_message (element, message);
1970 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1971 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1974 g_error_free (gerror);
1975 g_free (sent_debug);
1980 * gst_element_message_full:
1981 * @element: a #GstElement to send message from
1982 * @type: the #GstMessageType
1983 * @domain: the GStreamer GError domain this message belongs to
1984 * @code: the GError code belonging to the domain
1985 * @text: (allow-none) (transfer full): an allocated text string to be used
1986 * as a replacement for the default message connected to code,
1988 * @debug: (allow-none) (transfer full): an allocated debug message to be
1989 * used as a replacement for the default debugging information,
1991 * @file: the source code file where the error was generated
1992 * @function: the source code function where the error was generated
1993 * @line: the source code line where the error was generated
1995 * Post an error, warning or info message on the bus from inside an element.
1997 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1998 * #GST_MESSAGE_INFO.
2002 void gst_element_message_full
2003 (GstElement * element, GstMessageType type,
2004 GQuark domain, gint code, gchar * text,
2005 gchar * debug, const gchar * file, const gchar * function, gint line)
2007 gst_element_message_full_with_details (element, type, domain, code, text,
2008 debug, file, function, line, NULL);
2012 * gst_element_is_locked_state:
2013 * @element: a #GstElement.
2015 * Checks if the state of an element is locked.
2016 * If the state of an element is locked, state changes of the parent don't
2017 * affect the element.
2018 * This way you can leave currently unused elements inside bins. Just lock their
2019 * state before changing the state from #GST_STATE_NULL.
2023 * Returns: %TRUE, if the element's state is locked.
2026 gst_element_is_locked_state (GstElement * element)
2030 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2032 GST_OBJECT_LOCK (element);
2033 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2034 GST_OBJECT_UNLOCK (element);
2040 * gst_element_set_locked_state:
2041 * @element: a #GstElement
2042 * @locked_state: %TRUE to lock the element's state
2044 * Locks the state of an element, so state changes of the parent don't affect
2045 * this element anymore.
2049 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2050 * or the elements state-locking needed no change.
2053 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2057 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2059 GST_OBJECT_LOCK (element);
2060 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2062 if (G_UNLIKELY (old == locked_state))
2066 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2067 GST_ELEMENT_NAME (element));
2068 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2070 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2071 GST_ELEMENT_NAME (element));
2072 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2074 GST_OBJECT_UNLOCK (element);
2080 GST_CAT_DEBUG (GST_CAT_STATES,
2081 "elements %s was already in locked state %d",
2082 GST_ELEMENT_NAME (element), old);
2083 GST_OBJECT_UNLOCK (element);
2090 * gst_element_sync_state_with_parent:
2091 * @element: a #GstElement.
2093 * Tries to change the state of the element to the same as its parent.
2094 * If this function returns %FALSE, the state of element is undefined.
2096 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2101 gst_element_sync_state_with_parent (GstElement * element)
2105 GstStateChangeReturn ret;
2107 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2109 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2110 GstState parent_current, parent_pending;
2112 GST_OBJECT_LOCK (parent);
2113 parent_current = GST_STATE (parent);
2114 parent_pending = GST_STATE_PENDING (parent);
2115 GST_OBJECT_UNLOCK (parent);
2117 /* set to pending if there is one, else we set it to the current state of
2119 if (parent_pending != GST_STATE_VOID_PENDING)
2120 target = parent_pending;
2122 target = parent_current;
2124 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2125 "syncing state (%s) to parent %s %s (%s, %s)",
2126 gst_element_state_get_name (GST_STATE (element)),
2127 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2128 gst_element_state_get_name (parent_current),
2129 gst_element_state_get_name (parent_pending));
2131 ret = gst_element_set_state (element, target);
2132 if (ret == GST_STATE_CHANGE_FAILURE)
2135 gst_object_unref (parent);
2139 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2146 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2147 "syncing state failed (%s)",
2148 gst_element_state_change_return_get_name (ret));
2149 gst_object_unref (parent);
2155 static GstStateChangeReturn
2156 gst_element_get_state_func (GstElement * element,
2157 GstState * state, GstState * pending, GstClockTime timeout)
2159 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2160 GstState old_pending;
2162 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2163 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2165 GST_OBJECT_LOCK (element);
2166 ret = GST_STATE_RETURN (element);
2167 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2168 gst_element_state_change_return_get_name (ret));
2170 /* we got an error, report immediately */
2171 if (ret == GST_STATE_CHANGE_FAILURE)
2174 /* we got no_preroll, report immediately */
2175 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2178 /* no need to wait async if we are not async */
2179 if (ret != GST_STATE_CHANGE_ASYNC)
2182 old_pending = GST_STATE_PENDING (element);
2183 if (old_pending != GST_STATE_VOID_PENDING) {
2187 /* get cookie to detect state changes during waiting */
2188 cookie = element->state_cookie;
2190 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2191 "waiting for element to commit state");
2193 /* we have a pending state change, wait for it to complete */
2194 if (timeout != GST_CLOCK_TIME_NONE) {
2196 /* make timeout absolute */
2197 end_time = g_get_monotonic_time () + (timeout / 1000);
2198 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2200 GST_STATE_WAIT (element);
2205 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2206 /* timeout triggered */
2207 ret = GST_STATE_CHANGE_ASYNC;
2209 if (cookie != element->state_cookie)
2212 /* could be success or failure */
2213 if (old_pending == GST_STATE (element)) {
2214 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2215 ret = GST_STATE_CHANGE_SUCCESS;
2217 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2218 ret = GST_STATE_CHANGE_FAILURE;
2221 /* if nothing is pending anymore we can return SUCCESS */
2222 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2223 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2224 ret = GST_STATE_CHANGE_SUCCESS;
2230 *state = GST_STATE (element);
2232 *pending = GST_STATE_PENDING (element);
2234 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2235 "state current: %s, pending: %s, result: %s",
2236 gst_element_state_get_name (GST_STATE (element)),
2237 gst_element_state_get_name (GST_STATE_PENDING (element)),
2238 gst_element_state_change_return_get_name (ret));
2239 GST_OBJECT_UNLOCK (element);
2246 *state = GST_STATE_VOID_PENDING;
2248 *pending = GST_STATE_VOID_PENDING;
2250 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2252 GST_OBJECT_UNLOCK (element);
2254 return GST_STATE_CHANGE_FAILURE;
2259 * gst_element_get_state:
2260 * @element: a #GstElement to get the state of.
2261 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2263 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2264 * state. Can be %NULL.
2265 * @timeout: a #GstClockTime to specify the timeout for an async
2266 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2268 * Gets the state of the element.
2270 * For elements that performed an ASYNC state change, as reported by
2271 * gst_element_set_state(), this function will block up to the
2272 * specified timeout value for the state change to complete.
2273 * If the element completes the state change or goes into
2274 * an error, this function returns immediately with a return value of
2275 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2277 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2278 * returns the current and pending state immediately.
2280 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2281 * successfully changed its state but is not able to provide data yet.
2282 * This mostly happens for live sources that only produce data in
2283 * %GST_STATE_PLAYING. While the state change return is equivalent to
2284 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2285 * some sink elements might not be able to complete their state change because
2286 * an element is not producing data to complete the preroll. When setting the
2287 * element to playing, the preroll will complete and playback will start.
2289 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2290 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2291 * element is still performing a state change or
2292 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2296 GstStateChangeReturn
2297 gst_element_get_state (GstElement * element,
2298 GstState * state, GstState * pending, GstClockTime timeout)
2300 GstElementClass *oclass;
2301 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2303 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2305 oclass = GST_ELEMENT_GET_CLASS (element);
2307 if (oclass->get_state)
2308 result = (oclass->get_state) (element, state, pending, timeout);
2314 * gst_element_abort_state:
2315 * @element: a #GstElement to abort the state of.
2317 * Abort the state change of the element. This function is used
2318 * by elements that do asynchronous state changes and find out
2319 * something is wrong.
2321 * This function should be called with the STATE_LOCK held.
2326 gst_element_abort_state (GstElement * element)
2330 #ifndef GST_DISABLE_GST_DEBUG
2334 g_return_if_fail (GST_IS_ELEMENT (element));
2336 GST_OBJECT_LOCK (element);
2337 pending = GST_STATE_PENDING (element);
2339 if (pending == GST_STATE_VOID_PENDING ||
2340 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2341 goto nothing_aborted;
2343 #ifndef GST_DISABLE_GST_DEBUG
2344 old_state = GST_STATE (element);
2346 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2347 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2348 gst_element_state_get_name (pending));
2352 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2354 GST_STATE_BROADCAST (element);
2355 GST_OBJECT_UNLOCK (element);
2361 GST_OBJECT_UNLOCK (element);
2366 /* Not static because GstBin has manual state handling too */
2368 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2369 GstState newstate, GstState pending)
2371 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2372 GstMessage *message;
2374 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2375 "notifying about state-changed %s to %s (%s pending)",
2376 gst_element_state_get_name (oldstate),
2377 gst_element_state_get_name (newstate),
2378 gst_element_state_get_name (pending));
2380 if (klass->state_changed)
2381 klass->state_changed (element, oldstate, newstate, pending);
2383 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2384 oldstate, newstate, pending);
2385 gst_element_post_message (element, message);
2389 * gst_element_continue_state:
2390 * @element: a #GstElement to continue the state change of.
2391 * @ret: The previous state return value
2393 * Commit the state change of the element and proceed to the next
2394 * pending state if any. This function is used
2395 * by elements that do asynchronous state changes.
2396 * The core will normally call this method automatically when an
2397 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2399 * If after calling this method the element still has not reached
2400 * the pending state, the next state change is performed.
2402 * This method is used internally and should normally not be called by plugins
2405 * This function must be called with STATE_LOCK held.
2407 * Returns: The result of the commit state change.
2411 GstStateChangeReturn
2412 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2414 GstStateChangeReturn old_ret;
2415 GstState old_state, old_next;
2416 GstState current, next, pending;
2417 GstStateChange transition;
2419 GST_OBJECT_LOCK (element);
2420 old_ret = GST_STATE_RETURN (element);
2421 GST_STATE_RETURN (element) = ret;
2422 pending = GST_STATE_PENDING (element);
2424 /* check if there is something to commit */
2425 if (pending == GST_STATE_VOID_PENDING)
2426 goto nothing_pending;
2428 old_state = GST_STATE (element);
2429 /* this is the state we should go to next */
2430 old_next = GST_STATE_NEXT (element);
2431 /* update current state */
2432 current = GST_STATE (element) = old_next;
2434 /* see if we reached the final state */
2435 if (pending == current)
2438 next = GST_STATE_GET_NEXT (current, pending);
2439 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2441 GST_STATE_NEXT (element) = next;
2443 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2444 GST_OBJECT_UNLOCK (element);
2446 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2447 "committing state from %s to %s, pending %s, next %s",
2448 gst_element_state_get_name (old_state),
2449 gst_element_state_get_name (old_next),
2450 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2452 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2454 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2455 "continue state change %s to %s, final %s",
2456 gst_element_state_get_name (current),
2457 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2459 ret = gst_element_change_state (element, transition);
2465 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2466 GST_OBJECT_UNLOCK (element);
2471 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2472 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2474 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2475 "completed state change to %s", gst_element_state_get_name (pending));
2476 GST_OBJECT_UNLOCK (element);
2478 /* don't post silly messages with the same state. This can happen
2479 * when an element state is changed to what it already was. For bins
2480 * this can be the result of a lost state, which we check with the
2481 * previous return value.
2482 * We do signal the cond though as a _get_state() might be blocking
2484 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2485 _priv_gst_element_state_changed (element, old_state, old_next,
2486 GST_STATE_VOID_PENDING);
2488 GST_STATE_BROADCAST (element);
2495 * gst_element_lost_state:
2496 * @element: a #GstElement the state is lost of
2498 * Brings the element to the lost state. The current state of the
2499 * element is copied to the pending state so that any call to
2500 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2502 * An ASYNC_START message is posted. If the element was PLAYING, it will
2503 * go to PAUSED. The element will be restored to its PLAYING state by
2504 * the parent pipeline when it prerolls again.
2506 * This is mostly used for elements that lost their preroll buffer
2507 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2508 * they will go to their pending state again when a new preroll buffer is
2509 * queued. This function can only be called when the element is currently
2510 * not in error or an async state change.
2512 * This function is used internally and should normally not be called from
2513 * plugins or applications.
2516 gst_element_lost_state (GstElement * element)
2518 GstState old_state, new_state;
2519 GstMessage *message;
2521 g_return_if_fail (GST_IS_ELEMENT (element));
2523 GST_OBJECT_LOCK (element);
2524 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2527 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2528 goto only_async_start;
2530 old_state = GST_STATE (element);
2532 /* when we were PLAYING, the new state is PAUSED. We will also not
2533 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2534 * when we preroll. */
2535 if (old_state > GST_STATE_PAUSED)
2536 new_state = GST_STATE_PAUSED;
2538 new_state = old_state;
2540 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2541 "lost state of %s to %s", gst_element_state_get_name (old_state),
2542 gst_element_state_get_name (new_state));
2544 GST_STATE (element) = new_state;
2545 GST_STATE_NEXT (element) = new_state;
2546 GST_STATE_PENDING (element) = new_state;
2547 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2548 GST_OBJECT_UNLOCK (element);
2550 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2552 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2553 gst_element_post_message (element, message);
2559 GST_OBJECT_UNLOCK (element);
2564 GST_OBJECT_UNLOCK (element);
2566 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2567 gst_element_post_message (element, message);
2573 * gst_element_set_state:
2574 * @element: a #GstElement to change state of.
2575 * @state: the element's new #GstState.
2577 * Sets the state of the element. This function will try to set the
2578 * requested state by going through all the intermediary states and calling
2579 * the class's state change function for each.
2581 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2582 * element will perform the remainder of the state change asynchronously in
2584 * An application can use gst_element_get_state() to wait for the completion
2585 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2586 * %GST_MESSAGE_STATE_CHANGED on the bus.
2588 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2589 * #GST_STATE_CHANGE_ASYNC.
2591 * Returns: Result of the state change using #GstStateChangeReturn.
2595 GstStateChangeReturn
2596 gst_element_set_state (GstElement * element, GstState state)
2598 GstElementClass *oclass;
2599 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2601 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2603 oclass = GST_ELEMENT_GET_CLASS (element);
2605 if (oclass->set_state)
2606 result = (oclass->set_state) (element, state);
2612 * default set state function, calculates the next state based
2613 * on current state and calls the change_state function
2615 static GstStateChangeReturn
2616 gst_element_set_state_func (GstElement * element, GstState state)
2618 GstState current, next, old_pending;
2619 GstStateChangeReturn ret;
2620 GstStateChange transition;
2621 GstStateChangeReturn old_ret;
2623 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2625 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2626 gst_element_state_get_name (state));
2628 /* state lock is taken to protect the set_state() and get_state()
2629 * procedures, it does not lock any variables. */
2630 GST_STATE_LOCK (element);
2632 /* now calculate how to get to the new state */
2633 GST_OBJECT_LOCK (element);
2634 old_ret = GST_STATE_RETURN (element);
2635 /* previous state change returned an error, remove all pending
2636 * and next states */
2637 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2638 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2639 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2640 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2643 current = GST_STATE (element);
2644 next = GST_STATE_NEXT (element);
2645 old_pending = GST_STATE_PENDING (element);
2647 /* this is the (new) state we should go to. TARGET is the last state we set on
2649 if (state != GST_STATE_TARGET (element)) {
2650 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2651 "setting target state to %s", gst_element_state_get_name (state));
2652 GST_STATE_TARGET (element) = state;
2653 /* increment state cookie so that we can track each state change. We only do
2654 * this if this is actually a new state change. */
2655 element->state_cookie++;
2657 GST_STATE_PENDING (element) = state;
2659 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2660 "current %s, old_pending %s, next %s, old return %s",
2661 gst_element_state_get_name (current),
2662 gst_element_state_get_name (old_pending),
2663 gst_element_state_get_name (next),
2664 gst_element_state_change_return_get_name (old_ret));
2666 /* if the element was busy doing a state change, we just update the
2667 * target state, it'll get to it async then. */
2668 if (old_pending != GST_STATE_VOID_PENDING) {
2669 /* upwards state change will happen ASYNC */
2670 if (old_pending <= state)
2672 /* element is going to this state already */
2673 else if (next == state)
2675 /* element was performing an ASYNC upward state change and
2676 * we request to go downward again. Start from the next pending
2678 else if (next > state
2679 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2683 next = GST_STATE_GET_NEXT (current, state);
2684 /* now we store the next state */
2685 GST_STATE_NEXT (element) = next;
2686 /* mark busy, we need to check that there is actually a state change
2687 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2688 * the default element change_state function has no way to know what the
2689 * old value was... could consider this a FIXME...*/
2690 if (current != next)
2691 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2693 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2695 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2696 "%s: setting state from %s to %s",
2697 (next != state ? "intermediate" : "final"),
2698 gst_element_state_get_name (current), gst_element_state_get_name (next));
2700 /* now signal any waiters, they will error since the cookie was incremented */
2701 GST_STATE_BROADCAST (element);
2703 GST_OBJECT_UNLOCK (element);
2705 ret = gst_element_change_state (element, transition);
2707 GST_STATE_UNLOCK (element);
2709 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2710 gst_element_state_change_return_get_name (ret));
2716 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2717 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2718 "element was busy with async state change");
2719 GST_OBJECT_UNLOCK (element);
2721 GST_STATE_UNLOCK (element);
2723 return GST_STATE_CHANGE_ASYNC;
2728 * gst_element_change_state:
2729 * @element: a #GstElement
2730 * @transition: the requested transition
2732 * Perform @transition on @element.
2734 * This function must be called with STATE_LOCK held and is mainly used
2737 * Returns: the #GstStateChangeReturn of the state transition.
2739 GstStateChangeReturn
2740 gst_element_change_state (GstElement * element, GstStateChange transition)
2742 GstElementClass *oclass;
2743 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2745 oclass = GST_ELEMENT_GET_CLASS (element);
2747 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2749 /* call the state change function so it can set the state */
2750 if (oclass->change_state)
2751 ret = (oclass->change_state) (element, transition);
2753 ret = GST_STATE_CHANGE_FAILURE;
2755 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2758 case GST_STATE_CHANGE_FAILURE:
2759 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2760 "have FAILURE change_state return");
2761 /* state change failure */
2762 gst_element_abort_state (element);
2764 case GST_STATE_CHANGE_ASYNC:
2768 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2769 "element will change state ASYNC");
2771 target = GST_STATE_TARGET (element);
2773 if (target > GST_STATE_READY)
2776 /* else we just continue the state change downwards */
2777 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2778 "forcing commit state %s <= %s",
2779 gst_element_state_get_name (target),
2780 gst_element_state_get_name (GST_STATE_READY));
2782 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2785 case GST_STATE_CHANGE_SUCCESS:
2786 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2787 "element changed state SUCCESS");
2788 /* we can commit the state now which will proceeed to
2790 ret = gst_element_continue_state (element, ret);
2792 case GST_STATE_CHANGE_NO_PREROLL:
2793 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2794 "element changed state NO_PREROLL");
2795 /* we can commit the state now which will proceeed to
2797 ret = gst_element_continue_state (element, ret);
2800 goto invalid_return;
2803 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2808 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2816 GST_OBJECT_LOCK (element);
2817 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2818 g_critical ("%s: unknown return value %d from a state change function",
2819 GST_ELEMENT_NAME (element), ret);
2821 /* we are in error now */
2822 ret = GST_STATE_CHANGE_FAILURE;
2823 GST_STATE_RETURN (element) = ret;
2824 GST_OBJECT_UNLOCK (element);
2830 /* gst_iterator_fold functions for pads_activate
2831 * Stop the iterator if activating one pad failed, but only if that pad
2832 * has not been removed from the element. */
2834 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2836 GstPad *pad = g_value_get_object (vpad);
2837 gboolean cont = TRUE;
2839 if (!gst_pad_set_active (pad, *active)) {
2840 if (GST_PAD_PARENT (pad) != NULL) {
2842 g_value_set_boolean (ret, FALSE);
2849 /* returns false on error or early cutout of the fold, true if all
2850 * pads in @iter were (de)activated successfully. */
2852 iterator_activate_fold_with_resync (GstIterator * iter,
2853 GstIteratorFoldFunction func, gpointer user_data)
2855 GstIteratorResult ires;
2858 /* no need to unset this later, it's just a boolean */
2859 g_value_init (&ret, G_TYPE_BOOLEAN);
2860 g_value_set_boolean (&ret, TRUE);
2863 ires = gst_iterator_fold (iter, func, &ret, user_data);
2865 case GST_ITERATOR_RESYNC:
2866 /* need to reset the result again */
2867 g_value_set_boolean (&ret, TRUE);
2868 gst_iterator_resync (iter);
2870 case GST_ITERATOR_DONE:
2871 /* all pads iterated, return collected value */
2874 /* iterator returned _ERROR or premature end with _OK,
2875 * mark an error and exit */
2876 g_value_set_boolean (&ret, FALSE);
2881 /* return collected value */
2882 return g_value_get_boolean (&ret);
2885 /* is called with STATE_LOCK
2887 * Pads are activated from source pads to sinkpads.
2890 gst_element_pads_activate (GstElement * element, gboolean active)
2895 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2896 "%s pads", active ? "activate" : "deactivate");
2898 iter = gst_element_iterate_src_pads (element);
2900 iterator_activate_fold_with_resync (iter,
2901 (GstIteratorFoldFunction) activate_pads, &active);
2902 gst_iterator_free (iter);
2903 if (G_UNLIKELY (!res))
2906 iter = gst_element_iterate_sink_pads (element);
2908 iterator_activate_fold_with_resync (iter,
2909 (GstIteratorFoldFunction) activate_pads, &active);
2910 gst_iterator_free (iter);
2911 if (G_UNLIKELY (!res))
2914 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2915 "pad %sactivation successful", active ? "" : "de");
2922 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2923 "pad %sactivation failed", active ? "" : "de");
2928 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2929 "sink pads_activate failed");
2934 /* is called with STATE_LOCK */
2935 static GstStateChangeReturn
2936 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2938 GstState state, next;
2939 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2941 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2943 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2944 next = GST_STATE_TRANSITION_NEXT (transition);
2946 /* if the element already is in the given state, we just return success */
2947 if (next == GST_STATE_VOID_PENDING || state == next)
2950 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2951 "default handler tries setting state from %s to %s (%04x)",
2952 gst_element_state_get_name (state),
2953 gst_element_state_get_name (next), transition);
2955 switch (transition) {
2956 case GST_STATE_CHANGE_NULL_TO_READY:
2958 case GST_STATE_CHANGE_READY_TO_PAUSED:
2959 if (!gst_element_pads_activate (element, TRUE)) {
2960 result = GST_STATE_CHANGE_FAILURE;
2963 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2965 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2967 case GST_STATE_CHANGE_PAUSED_TO_READY:
2968 case GST_STATE_CHANGE_READY_TO_NULL:{
2971 /* deactivate pads in both cases, since they are activated on
2972 ready->paused but the element might not have made it to paused */
2973 if (!gst_element_pads_activate (element, FALSE)) {
2974 result = GST_STATE_CHANGE_FAILURE;
2977 /* Remove all non-persistent contexts */
2978 GST_OBJECT_LOCK (element);
2979 for (l = element->contexts; l;) {
2980 GstContext *context = l->data;
2982 if (!gst_context_is_persistent (context)) {
2985 gst_context_unref (context);
2987 element->contexts = g_list_delete_link (element->contexts, l);
2993 GST_OBJECT_UNLOCK (element);
2997 /* this will catch real but unhandled state changes;
2998 * can only be caused by:
2999 * - a new state was added
3000 * - somehow the element was asked to jump across an intermediate state
3002 g_warning ("Unhandled state change from %s to %s",
3003 gst_element_state_get_name (state),
3004 gst_element_state_get_name (next));
3011 GST_OBJECT_LOCK (element);
3012 result = GST_STATE_RETURN (element);
3013 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3014 "element is already in the %s state",
3015 gst_element_state_get_name (state));
3016 GST_OBJECT_UNLOCK (element);
3023 * gst_element_get_factory:
3024 * @element: a #GstElement to request the element factory of.
3026 * Retrieves the factory that was used to create this element.
3028 * Returns: (transfer none): the #GstElementFactory used for creating this
3029 * element. no refcounting is needed.
3032 gst_element_get_factory (GstElement * element)
3034 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3036 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3040 gst_element_dispose (GObject * object)
3042 GstElement *element = GST_ELEMENT_CAST (object);
3045 GstElementClass *oclass;
3048 oclass = GST_ELEMENT_GET_CLASS (element);
3050 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3052 if (GST_STATE (element) != GST_STATE_NULL)
3055 /* start by releasing all request pads, this might also remove some dynamic
3057 walk = element->pads;
3059 GstPad *pad = GST_PAD_CAST (walk->data);
3063 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3064 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3065 == GST_PAD_REQUEST) {
3066 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3067 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3068 oclass->release_pad (element, pad);
3070 /* in case the release_pad function removed the next pad too */
3071 if (walk && g_list_position (element->pads, walk) == -1)
3072 walk = element->pads;
3075 /* remove the remaining pads */
3076 while (element->pads) {
3077 GstPad *pad = GST_PAD_CAST (element->pads->data);
3078 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3079 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3080 if (!gst_element_remove_pad (element, pad)) {
3081 /* only happens when someone unparented our pad.. */
3082 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3087 GST_OBJECT_LOCK (element);
3088 clock_p = &element->clock;
3089 bus_p = &element->bus;
3090 gst_object_replace ((GstObject **) clock_p, NULL);
3091 gst_object_replace ((GstObject **) bus_p, NULL);
3092 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3093 GST_OBJECT_UNLOCK (element);
3095 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3098 G_OBJECT_CLASS (parent_class)->dispose (object);
3107 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3109 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3111 "You need to explicitly set elements to the NULL state before\n"
3112 "dropping the final reference, to allow them to clean up.\n"
3113 "This problem may also be caused by a refcounting bug in the\n"
3114 "application or some element.\n",
3115 GST_OBJECT_NAME (element),
3116 gst_element_state_get_name (GST_STATE (element)),
3117 is_locked ? " (locked)" : "");
3123 gst_element_finalize (GObject * object)
3125 GstElement *element = GST_ELEMENT_CAST (object);
3127 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3129 g_cond_clear (&element->state_cond);
3130 g_rec_mutex_clear (&element->state_lock);
3132 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3135 G_OBJECT_CLASS (parent_class)->finalize (object);
3139 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3143 g_return_if_fail (GST_IS_ELEMENT (element));
3145 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3147 GST_OBJECT_LOCK (element);
3148 bus_p = &GST_ELEMENT_BUS (element);
3149 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3150 GST_OBJECT_UNLOCK (element);
3154 * gst_element_set_bus:
3155 * @element: a #GstElement to set the bus of.
3156 * @bus: (transfer none): the #GstBus to set.
3158 * Sets the bus of the element. Increases the refcount on the bus.
3159 * For internal use only, unless you're testing elements.
3164 gst_element_set_bus (GstElement * element, GstBus * bus)
3166 GstElementClass *oclass;
3168 g_return_if_fail (GST_IS_ELEMENT (element));
3170 oclass = GST_ELEMENT_GET_CLASS (element);
3172 if (oclass->set_bus)
3173 oclass->set_bus (element, bus);
3177 * gst_element_get_bus:
3178 * @element: a #GstElement to get the bus of.
3180 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3181 * bus for the application.
3183 * Returns: (transfer full): the element's #GstBus. unref after usage.
3188 gst_element_get_bus (GstElement * element)
3190 GstBus *result = NULL;
3192 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3194 GST_OBJECT_LOCK (element);
3195 if ((result = GST_ELEMENT_BUS (element)))
3196 gst_object_ref (result);
3197 GST_OBJECT_UNLOCK (element);
3199 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3206 gst_element_set_context_default (GstElement * element, GstContext * context)
3208 const gchar *context_type;
3211 g_return_if_fail (GST_IS_CONTEXT (context));
3212 context_type = gst_context_get_context_type (context);
3213 g_return_if_fail (context_type != NULL);
3215 GST_OBJECT_LOCK (element);
3216 for (l = element->contexts; l; l = l->next) {
3217 GstContext *tmp = l->data;
3218 const gchar *tmp_type = gst_context_get_context_type (tmp);
3220 /* Always store newest context but never replace
3221 * a persistent one by a non-persistent one */
3222 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3223 (gst_context_is_persistent (context) ||
3224 !gst_context_is_persistent (tmp))) {
3225 gst_context_replace ((GstContext **) & l->data, context);
3229 /* Not found? Add */
3232 g_list_prepend (element->contexts, gst_context_ref (context));
3234 GST_OBJECT_UNLOCK (element);
3238 * gst_element_set_context:
3239 * @element: a #GstElement to set the context of.
3240 * @context: (transfer none): the #GstContext to set.
3242 * Sets the context of the element. Increases the refcount of the context.
3247 gst_element_set_context (GstElement * element, GstContext * context)
3249 GstElementClass *oclass;
3251 g_return_if_fail (GST_IS_ELEMENT (element));
3252 g_return_if_fail (GST_IS_CONTEXT (context));
3254 oclass = GST_ELEMENT_GET_CLASS (element);
3256 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3257 "set context %p %" GST_PTR_FORMAT, context,
3258 gst_context_get_structure (context));
3260 if (oclass->set_context)
3261 oclass->set_context (element, context);
3265 * gst_element_get_contexts:
3266 * @element: a #GstElement to set the context of.
3268 * Gets the contexts set on the element.
3272 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3277 gst_element_get_contexts (GstElement * element)
3281 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3283 GST_OBJECT_LOCK (element);
3284 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3285 GST_OBJECT_UNLOCK (element);
3291 _match_context_type (GstContext * c1, const gchar * context_type)
3293 const gchar *c1_type;
3295 c1_type = gst_context_get_context_type (c1);
3297 return g_strcmp0 (c1_type, context_type);
3301 * gst_element_get_context_unlocked:
3302 * @element: a #GstElement to get the context of.
3303 * @context_type: a name of a context to retrieve
3305 * Gets the context with @context_type set on the element or NULL.
3307 * Returns: (transfer full): A #GstContext or NULL
3312 gst_element_get_context_unlocked (GstElement * element,
3313 const gchar * context_type)
3315 GstContext *ret = NULL;
3318 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3321 g_list_find_custom (element->contexts, context_type,
3322 (GCompareFunc) _match_context_type);
3323 if (node && node->data)
3324 ret = gst_context_ref (node->data);
3330 * gst_element_get_context:
3331 * @element: a #GstElement to get the context of.
3332 * @context_type: a name of a context to retrieve
3334 * Gets the context with @context_type set on the element or NULL.
3338 * Returns: (transfer full): A #GstContext or NULL
3343 gst_element_get_context (GstElement * element, const gchar * context_type)
3345 GstContext *ret = NULL;
3347 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3349 GST_OBJECT_LOCK (element);
3350 ret = gst_element_get_context_unlocked (element, context_type);
3351 GST_OBJECT_UNLOCK (element);
3357 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3358 GParamSpec * pspec, gboolean include_value)
3360 GValue val = G_VALUE_INIT;
3363 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3364 "changed, posting message with%s value", pspec->name, obj,
3365 include_value ? "" : "out");
3367 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3368 g_value_init (&val, pspec->value_type);
3369 g_object_get_property (obj, pspec->name, &val);
3374 gst_element_post_message (element,
3375 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3379 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3380 GParamSpec * pspec, gpointer user_data)
3382 gboolean include_value = GPOINTER_TO_INT (user_data);
3384 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3389 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3392 gboolean include_value = GPOINTER_TO_INT (user_data);
3394 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3399 * gst_element_add_property_notify_watch:
3400 * @element: a #GstElement to watch for property changes
3401 * @property_name: (allow-none): name of property to watch for changes, or
3402 * NULL to watch all properties
3403 * @include_value: whether to include the new property value in the message
3405 * Returns: a watch id, which can be used in connection with
3406 * gst_element_remove_property_notify_watch() to remove the watch again.
3411 gst_element_add_property_notify_watch (GstElement * element,
3412 const gchar * property_name, gboolean include_value)
3418 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3420 sep = (property_name != NULL) ? "::" : NULL;
3421 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3422 id = g_signal_connect (element, signal_name,
3423 G_CALLBACK (gst_element_property_notify_cb),
3424 GINT_TO_POINTER (include_value));
3425 g_free (signal_name);
3431 * gst_element_add_property_deep_notify_watch:
3432 * @element: a #GstElement to watch (recursively) for property changes
3433 * @property_name: (allow-none): name of property to watch for changes, or
3434 * NULL to watch all properties
3435 * @include_value: whether to include the new property value in the message
3437 * Returns: a watch id, which can be used in connection with
3438 * gst_element_remove_property_notify_watch() to remove the watch again.
3443 gst_element_add_property_deep_notify_watch (GstElement * element,
3444 const gchar * property_name, gboolean include_value)
3450 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3452 sep = (property_name != NULL) ? "::" : NULL;
3453 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3454 id = g_signal_connect (element, signal_name,
3455 G_CALLBACK (gst_element_property_deep_notify_cb),
3456 GINT_TO_POINTER (include_value));
3457 g_free (signal_name);
3463 * gst_element_remove_property_notify_watch:
3464 * @element: a #GstElement being watched for property changes
3465 * @watch_id: watch id to remove
3470 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3472 g_signal_handler_disconnect (element, watch_id);
3477 GstElement *element;
3478 GstElementCallAsyncFunc func;
3480 GDestroyNotify destroy_notify;
3481 } GstElementCallAsyncData;
3484 gst_element_call_async_func (gpointer data, gpointer user_data)
3486 GstElementCallAsyncData *async_data = data;
3488 async_data->func (async_data->element, async_data->user_data);
3489 if (async_data->destroy_notify)
3490 async_data->destroy_notify (async_data->user_data);
3491 gst_object_unref (async_data->element);
3492 g_free (async_data);
3496 * gst_element_call_async:
3497 * @element: a #GstElement
3498 * @func: Function to call asynchronously from another thread
3499 * @user_data: Data to pass to @func
3500 * @destroy_notify: GDestroyNotify for @user_data
3502 * Calls @func from another thread and passes @user_data to it. This is to be
3503 * used for cases when a state change has to be performed from a streaming
3504 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3507 * Calling those functions directly from the streaming thread will cause
3508 * deadlocks in many situations, as they might involve waiting for the
3509 * streaming thread to shut down from this very streaming thread.
3516 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3517 gpointer user_data, GDestroyNotify destroy_notify)
3519 GstElementCallAsyncData *async_data;
3521 g_return_if_fail (GST_IS_ELEMENT (element));
3523 async_data = g_new0 (GstElementCallAsyncData, 1);
3524 async_data->element = gst_object_ref (element);
3525 async_data->func = func;
3526 async_data->user_data = user_data;
3527 async_data->destroy_notify = destroy_notify;
3529 g_thread_pool_push (gst_element_pool, async_data, NULL);
3533 _priv_gst_element_cleanup (void)
3535 if (gst_element_pool) {
3536 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3537 gst_element_setup_thread_pool ();
3542 gst_make_element_message_details (const char *name, ...)
3544 GstStructure *structure;
3550 va_start (varargs, name);
3551 structure = gst_structure_new_valist ("details", name, varargs);