2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
26 * @short_description: Abstract base class for all pipeline elements
27 * @see_also: #GstElementFactory, #GstPad
29 * GstElement is the abstract base class needed to construct an element that
30 * can be used in a GStreamer pipeline. Please refer to the plugin writers
31 * guide for more information on creating #GstElement subclasses.
33 * The name of a #GstElement can be get with gst_element_get_name() and set with
34 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
35 * core when using the appropriate locking. Do not use this in plug-ins or
36 * applications in order to retain ABI compatibility.
38 * Elements can have pads (of the type #GstPad). These pads link to pads on
39 * other elements. #GstBuffer flow between these linked pads.
40 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
41 * and output (or source) pads.
42 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
43 * and gst_element_remove_pad().
45 * An existing pad of an element can be retrieved by name with
46 * gst_element_get_static_pad(). A new dynamic pad can be created using
47 * gst_element_request_pad() with a #GstPadTemplate.
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If the
72 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock selection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
80 #include "gst_private.h"
83 #include <gobject/gvaluecollector.h>
85 #include "gstelement.h"
86 #include "gstelementmetadata.h"
87 #include "gstenumtypes.h"
94 #include "gsttracerutils.h"
96 #include "gst-i18n-lib.h"
97 #include "glib-compat-private.h"
99 #ifndef GST_DISABLE_GST_DEBUG
100 #include "printf/printf.h"
103 /* Element signals and args */
119 static void gst_element_class_init (GstElementClass * klass);
120 static void gst_element_init (GstElement * element);
121 static void gst_element_base_class_init (gpointer g_class);
123 static void gst_element_constructed (GObject * object);
124 static void gst_element_dispose (GObject * object);
125 static void gst_element_finalize (GObject * object);
127 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
128 GstStateChange transition);
129 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
130 GstState * state, GstState * pending, GstClockTime timeout);
131 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
133 static gboolean gst_element_set_clock_func (GstElement * element,
135 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
136 static gboolean gst_element_post_message_default (GstElement * element,
137 GstMessage * message);
138 static void gst_element_set_context_default (GstElement * element,
139 GstContext * context);
141 static gboolean gst_element_default_send_event (GstElement * element,
143 static gboolean gst_element_default_query (GstElement * element,
146 static GstPadTemplate
147 * gst_element_class_get_request_pad_template (GstElementClass *
148 element_class, const gchar * name);
150 static void gst_element_call_async_func (gpointer data, gpointer user_data);
152 static GstObjectClass *parent_class = NULL;
153 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
155 static GThreadPool *gst_element_pool = NULL;
157 /* this is used in gstelementfactory.c:gst_element_register() */
158 GQuark __gst_elementclass_factory = 0;
161 gst_element_get_type (void)
163 static volatile gsize gst_element_type = 0;
165 if (g_once_init_enter (&gst_element_type)) {
167 static const GTypeInfo element_info = {
168 sizeof (GstElementClass),
169 gst_element_base_class_init,
170 NULL, /* base_class_finalize */
171 (GClassInitFunc) gst_element_class_init,
176 (GInstanceInitFunc) gst_element_init,
180 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
181 &element_info, G_TYPE_FLAG_ABSTRACT);
183 __gst_elementclass_factory =
184 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
185 g_once_init_leave (&gst_element_type, _type);
187 return gst_element_type;
191 gst_element_setup_thread_pool (void)
195 GST_DEBUG ("creating element thread pool");
197 g_thread_pool_new ((GFunc) gst_element_call_async_func, NULL, -1, FALSE,
200 g_critical ("could not alloc threadpool %s", err->message);
201 g_clear_error (&err);
206 gst_element_class_init (GstElementClass * klass)
208 GObjectClass *gobject_class;
210 gobject_class = (GObjectClass *) klass;
212 parent_class = g_type_class_peek_parent (klass);
215 * GstElement::pad-added:
216 * @gstelement: the object which received the signal
217 * @new_pad: the pad that has been added
219 * a new #GstPad has been added to the element. Note that this signal will
220 * usually be emitted from the context of the streaming thread. Also keep in
221 * mind that if you add new elements to the pipeline in the signal handler
222 * you will need to set them to the desired target state with
223 * gst_element_set_state() or gst_element_sync_state_with_parent().
225 gst_element_signals[PAD_ADDED] =
226 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
227 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
228 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
230 * GstElement::pad-removed:
231 * @gstelement: the object which received the signal
232 * @old_pad: the pad that has been removed
234 * a #GstPad has been removed from the element
236 gst_element_signals[PAD_REMOVED] =
237 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
238 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
239 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
241 * GstElement::no-more-pads:
242 * @gstelement: the object which received the signal
244 * This signals that the element will not generate more dynamic pads.
245 * Note that this signal will usually be emitted from the context of
246 * the streaming thread.
248 gst_element_signals[NO_MORE_PADS] =
249 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
250 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
251 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
253 gobject_class->dispose = gst_element_dispose;
254 gobject_class->finalize = gst_element_finalize;
255 gobject_class->constructed = gst_element_constructed;
257 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
258 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
259 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
260 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
261 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
262 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
263 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
264 klass->numpadtemplates = 0;
265 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
266 klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_default);
268 klass->elementfactory = NULL;
270 gst_element_setup_thread_pool ();
274 gst_element_base_class_init (gpointer g_class)
276 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
277 GList *node, *padtemplates;
279 /* Copy the element details here so elements can inherit the
280 * details from their base class and classes only need to set
281 * the details in class_init instead of base_init */
282 element_class->metadata =
283 element_class->metadata ? gst_structure_copy (element_class->metadata) :
284 gst_structure_new_empty ("metadata");
286 /* Copy the pad templates so elements inherit them
287 * from their base class but elements can add pad templates in class_init
288 * instead of base_init.
290 padtemplates = g_list_copy (element_class->padtemplates);
291 for (node = padtemplates; node != NULL; node = node->next) {
292 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
293 gst_object_ref (tmpl);
295 element_class->padtemplates = padtemplates;
297 /* set the factory, see gst_element_register() */
298 element_class->elementfactory =
299 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
300 __gst_elementclass_factory);
301 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
302 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
306 gst_element_init (GstElement * element)
308 GST_STATE (element) = GST_STATE_NULL;
309 GST_STATE_TARGET (element) = GST_STATE_NULL;
310 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
311 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
312 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
314 g_rec_mutex_init (&element->state_lock);
315 g_cond_init (&element->state_cond);
319 gst_element_constructed (GObject * object)
321 GST_TRACER_ELEMENT_NEW (GST_ELEMENT_CAST (object));
322 G_OBJECT_CLASS (parent_class)->constructed (object);
326 * gst_element_release_request_pad:
327 * @element: a #GstElement to release the request pad of.
328 * @pad: the #GstPad to release.
330 * Makes the element free the previously requested pad as obtained
331 * with gst_element_request_pad().
333 * This does not unref the pad. If the pad was created by using
334 * gst_element_request_pad(), gst_element_release_request_pad() needs to be
335 * followed by gst_object_unref() to free the @pad.
340 gst_element_release_request_pad (GstElement * element, GstPad * pad)
342 GstElementClass *oclass;
344 g_return_if_fail (GST_IS_ELEMENT (element));
345 g_return_if_fail (GST_IS_PAD (pad));
346 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
347 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
349 g_return_if_fail (GST_PAD_PARENT (pad) == element);
351 oclass = GST_ELEMENT_GET_CLASS (element);
353 /* if the element implements a custom release function we call that, else we
354 * simply remove the pad from the element */
355 if (oclass->release_pad)
356 oclass->release_pad (element, pad);
358 gst_element_remove_pad (element, pad);
362 * gst_element_provide_clock:
363 * @element: a #GstElement to query
365 * Get the clock provided by the given element.
366 * > An element is only required to provide a clock in the PAUSED
367 * > state. Some elements can provide a clock in other states.
369 * Returns: (transfer full) (nullable): the GstClock provided by the
370 * element or %NULL if no clock could be provided. Unref after usage.
375 gst_element_provide_clock (GstElement * element)
377 GstClock *result = NULL;
378 GstElementClass *oclass;
380 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
382 oclass = GST_ELEMENT_GET_CLASS (element);
384 if (oclass->provide_clock)
385 result = oclass->provide_clock (element);
391 gst_element_set_clock_func (GstElement * element, GstClock * clock)
395 GST_OBJECT_LOCK (element);
396 clock_p = &element->clock;
397 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
398 GST_OBJECT_UNLOCK (element);
404 * gst_element_set_clock:
405 * @element: a #GstElement to set the clock for.
406 * @clock: the #GstClock to set for the element.
408 * Sets the clock for the element. This function increases the
409 * refcount on the clock. Any previously set clock on the object
412 * Returns: %TRUE if the element accepted the clock. An element can refuse a
413 * clock when it, for example, is not able to slave its internal clock to the
414 * @clock or when it requires a specific clock to operate.
419 gst_element_set_clock (GstElement * element, GstClock * clock)
421 GstElementClass *oclass;
422 gboolean res = FALSE;
424 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
425 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
427 oclass = GST_ELEMENT_GET_CLASS (element);
429 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
431 if (oclass->set_clock)
432 res = oclass->set_clock (element, clock);
438 * gst_element_get_clock:
439 * @element: a #GstElement to get the clock of.
441 * Gets the currently configured clock of the element. This is the clock as was
442 * last set with gst_element_set_clock().
444 * Elements in a pipeline will only have their clock set when the
445 * pipeline is in the PLAYING state.
447 * Returns: (transfer full): the #GstClock of the element. unref after usage.
452 gst_element_get_clock (GstElement * element)
456 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
458 GST_OBJECT_LOCK (element);
459 if ((result = element->clock))
460 gst_object_ref (result);
461 GST_OBJECT_UNLOCK (element);
467 * gst_element_set_base_time:
468 * @element: a #GstElement.
469 * @time: the base time to set.
471 * Set the base time of an element. See gst_element_get_base_time().
476 gst_element_set_base_time (GstElement * element, GstClockTime time)
480 g_return_if_fail (GST_IS_ELEMENT (element));
482 GST_OBJECT_LOCK (element);
483 old = element->base_time;
484 element->base_time = time;
485 GST_OBJECT_UNLOCK (element);
487 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
488 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
489 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
493 * gst_element_get_base_time:
494 * @element: a #GstElement.
496 * Returns the base time of the element. The base time is the
497 * absolute time of the clock when this element was last put to
498 * PLAYING. Subtracting the base time from the clock time gives
499 * the running time of the element.
501 * Returns: the base time of the element.
506 gst_element_get_base_time (GstElement * element)
510 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
512 GST_OBJECT_LOCK (element);
513 result = element->base_time;
514 GST_OBJECT_UNLOCK (element);
520 * gst_element_set_start_time:
521 * @element: a #GstElement.
522 * @time: the base time to set.
524 * Set the start time of an element. The start time of the element is the
525 * running time of the element when it last went to the PAUSED state. In READY
526 * or after a flushing seek, it is set to 0.
528 * Toplevel elements like #GstPipeline will manage the start_time and
529 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
530 * on such a toplevel element will disable the distribution of the base_time to
531 * the children and can be useful if the application manages the base_time
532 * itself, for example if you want to synchronize capture from multiple
533 * pipelines, and you can also ensure that the pipelines have the same clock.
538 gst_element_set_start_time (GstElement * element, GstClockTime time)
542 g_return_if_fail (GST_IS_ELEMENT (element));
544 GST_OBJECT_LOCK (element);
545 old = GST_ELEMENT_START_TIME (element);
546 GST_ELEMENT_START_TIME (element) = time;
547 GST_OBJECT_UNLOCK (element);
549 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
550 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
551 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
555 * gst_element_get_start_time:
556 * @element: a #GstElement.
558 * Returns the start time of the element. The start time is the
559 * running time of the clock when this element was last put to PAUSED.
561 * Usually the start_time is managed by a toplevel element such as
566 * Returns: the start time of the element.
569 gst_element_get_start_time (GstElement * element)
573 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
575 GST_OBJECT_LOCK (element);
576 result = GST_ELEMENT_START_TIME (element);
577 GST_OBJECT_UNLOCK (element);
584 * gst_element_set_index:
585 * @element: a #GstElement.
586 * @index: (transfer none): a #GstIndex.
588 * Set @index on the element. The refcount of the index
589 * will be increased, any previously set index is unreffed.
594 gst_element_set_index (GstElement * element, GstIndex * index)
596 GstElementClass *oclass;
598 g_return_if_fail (GST_IS_ELEMENT (element));
599 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
601 oclass = GST_ELEMENT_GET_CLASS (element);
603 if (oclass->set_index)
604 oclass->set_index (element, index);
608 * gst_element_get_index:
609 * @element: a #GstElement.
611 * Gets the index from the element.
613 * Returns: (transfer full) (nullable): a #GstIndex or %NULL when no
614 * index was set on the element. unref after usage.
619 gst_element_get_index (GstElement * element)
621 GstElementClass *oclass;
622 GstIndex *result = NULL;
624 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
626 oclass = GST_ELEMENT_GET_CLASS (element);
628 if (oclass->get_index)
629 result = oclass->get_index (element);
636 * gst_element_add_pad:
637 * @element: a #GstElement to add the pad to.
638 * @pad: (transfer full): the #GstPad to add to the element.
640 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
641 * see gst_object_set_parent() for refcounting information.
643 * Pads are not automatically activated so elements should perform the needed
644 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
645 * state. See gst_pad_set_active() for more information about activating pads.
647 * The pad and the element should be unlocked when calling this function.
649 * This function will emit the #GstElement::pad-added signal on the element.
651 * Returns: %TRUE if the pad could be added. This function can fail when
652 * a pad with the same name already existed or the pad already had another
658 gst_element_add_pad (GstElement * element, GstPad * pad)
663 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
664 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
666 /* locking pad to look at the name */
667 GST_OBJECT_LOCK (pad);
668 pad_name = g_strdup (GST_PAD_NAME (pad));
669 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
670 GST_STR_NULL (pad_name));
671 active = GST_PAD_IS_ACTIVE (pad);
672 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
673 GST_OBJECT_UNLOCK (pad);
675 /* then check to see if there's already a pad by that name here */
676 GST_OBJECT_LOCK (element);
677 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
680 /* try to set the pad's parent */
681 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
682 GST_OBJECT_CAST (element))))
685 /* check for active pads */
686 if (!active && (GST_STATE (element) > GST_STATE_READY ||
687 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
688 g_warning ("adding inactive pad '%s' to running element '%s', you need to "
689 "use gst_pad_set_active(pad,TRUE) before adding it.",
690 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
691 gst_pad_set_active (pad, TRUE);
696 /* add it to the list */
697 switch (gst_pad_get_direction (pad)) {
699 element->srcpads = g_list_append (element->srcpads, pad);
700 element->numsrcpads++;
703 element->sinkpads = g_list_append (element->sinkpads, pad);
704 element->numsinkpads++;
709 element->pads = g_list_append (element->pads, pad);
711 element->pads_cookie++;
712 GST_OBJECT_UNLOCK (element);
714 /* emit the PAD_ADDED signal */
715 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
716 GST_TRACER_ELEMENT_ADD_PAD (element, pad);
722 g_critical ("Padname %s is not unique in element %s, not adding",
723 pad_name, GST_ELEMENT_NAME (element));
724 GST_OBJECT_UNLOCK (element);
726 gst_object_ref_sink (pad);
727 gst_object_unref (pad);
733 ("Pad %s already has parent when trying to add to element %s",
734 pad_name, GST_ELEMENT_NAME (element));
735 GST_OBJECT_UNLOCK (element);
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 full): 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.
1261 gst_element_class_add_pad_template (GstElementClass * klass,
1262 GstPadTemplate * templ)
1264 GList *template_list = klass->padtemplates;
1266 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1267 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1269 /* If we already have a pad template with the same name replace the
1271 while (template_list) {
1272 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1274 /* Found pad with the same name, replace and return */
1275 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1276 gst_object_ref_sink (padtempl);
1277 gst_object_unref (padtempl);
1278 template_list->data = templ;
1281 template_list = g_list_next (template_list);
1284 /* Take ownership of the floating ref */
1285 gst_object_ref_sink (templ);
1287 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1288 klass->numpadtemplates++;
1292 * gst_element_class_add_static_pad_template:
1293 * @klass: the #GstElementClass to add the pad template to.
1294 * @static_templ: #GstStaticPadTemplate to add as pad template to the element class.
1296 * Adds a pad template to an element class based on the static pad template
1297 * @templ. This is mainly used in the _class_init functions of element
1298 * implementations. If a pad template with the same name already exists,
1299 * the old one is replaced by the new one.
1304 gst_element_class_add_static_pad_template (GstElementClass * klass,
1305 GstStaticPadTemplate * static_templ)
1307 gst_element_class_add_pad_template (klass,
1308 gst_static_pad_template_get (static_templ));
1312 * gst_element_class_add_metadata:
1313 * @klass: class to set metadata for
1314 * @key: the key to set
1315 * @value: the value to set
1317 * Set @key with @value as metadata in @klass.
1320 gst_element_class_add_metadata (GstElementClass * klass,
1321 const gchar * key, const gchar * value)
1323 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1324 g_return_if_fail (key != NULL);
1325 g_return_if_fail (value != NULL);
1327 gst_structure_set ((GstStructure *) klass->metadata,
1328 key, G_TYPE_STRING, value, NULL);
1332 * gst_element_class_add_static_metadata:
1333 * @klass: class to set metadata for
1334 * @key: the key to set
1335 * @value: the value to set
1337 * Set @key with @value as metadata in @klass.
1339 * Same as gst_element_class_add_metadata(), but @value must be a static string
1340 * or an inlined string, as it will not be copied. (GStreamer plugins will
1341 * be made resident once loaded, so this function can be used even from
1342 * dynamically loaded plugins.)
1345 gst_element_class_add_static_metadata (GstElementClass * klass,
1346 const gchar * key, const gchar * value)
1348 GValue val = G_VALUE_INIT;
1350 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1351 g_return_if_fail (key != NULL);
1352 g_return_if_fail (value != NULL);
1354 g_value_init (&val, G_TYPE_STRING);
1355 g_value_set_static_string (&val, value);
1356 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1360 * gst_element_class_set_metadata:
1361 * @klass: class to set metadata for
1362 * @longname: The long English name of the element. E.g. "File Sink"
1363 * @classification: String describing the type of element, as an unordered list
1364 * separated with slashes ('/'). See draft-klass.txt of the design docs
1365 * for more details and common types. E.g: "Sink/File"
1366 * @description: Sentence describing the purpose of the element.
1367 * E.g: "Write stream to a file"
1368 * @author: Name and contact details of the author(s). Use \n to separate
1369 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1371 * Sets the detailed information for a #GstElementClass.
1372 * > This function is for use in _class_init functions only.
1375 gst_element_class_set_metadata (GstElementClass * klass,
1376 const gchar * longname, const gchar * classification,
1377 const gchar * description, const gchar * author)
1379 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1380 g_return_if_fail (longname != NULL && *longname != '\0');
1381 g_return_if_fail (classification != NULL && *classification != '\0');
1382 g_return_if_fail (description != NULL && *description != '\0');
1383 g_return_if_fail (author != NULL && *author != '\0');
1385 gst_structure_id_set ((GstStructure *) klass->metadata,
1386 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1387 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1388 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1389 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1393 * gst_element_class_set_static_metadata:
1394 * @klass: class to set metadata for
1395 * @longname: The long English name of the element. E.g. "File Sink"
1396 * @classification: String describing the type of element, as an unordered list
1397 * separated with slashes ('/'). See draft-klass.txt of the design docs
1398 * for more details and common types. E.g: "Sink/File"
1399 * @description: Sentence describing the purpose of the element.
1400 * E.g: "Write stream to a file"
1401 * @author: Name and contact details of the author(s). Use \n to separate
1402 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1404 * Sets the detailed information for a #GstElementClass.
1406 * > This function is for use in _class_init functions only.
1408 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1409 * @description, and @author must be static strings or inlined strings, as
1410 * they will not be copied. (GStreamer plugins will be made resident once
1411 * loaded, so this function can be used even from dynamically loaded plugins.)
1414 gst_element_class_set_static_metadata (GstElementClass * klass,
1415 const gchar * longname, const gchar * classification,
1416 const gchar * description, const gchar * author)
1418 GstStructure *s = (GstStructure *) klass->metadata;
1419 GValue val = G_VALUE_INIT;
1421 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1422 g_return_if_fail (longname != NULL && *longname != '\0');
1423 g_return_if_fail (classification != NULL && *classification != '\0');
1424 g_return_if_fail (description != NULL && *description != '\0');
1425 g_return_if_fail (author != NULL && *author != '\0');
1427 g_value_init (&val, G_TYPE_STRING);
1429 g_value_set_static_string (&val, longname);
1430 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1432 g_value_set_static_string (&val, classification);
1433 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1435 g_value_set_static_string (&val, description);
1436 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1439 g_value_set_static_string (&val, author);
1440 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1444 * gst_element_class_get_metadata:
1445 * @klass: class to get metadata for
1446 * @key: the key to get
1448 * Get metadata with @key in @klass.
1450 * Returns: the metadata for @key.
1453 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1455 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1456 g_return_val_if_fail (key != NULL, NULL);
1458 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1462 * gst_element_class_get_pad_template_list:
1463 * @element_class: a #GstElementClass to get pad templates of.
1465 * Retrieves a list of the pad templates associated with @element_class. The
1466 * list must not be modified by the calling code.
1467 * > If you use this function in the #GInstanceInitFunc of an object class
1468 * > that has subclasses, make sure to pass the g_class parameter of the
1469 * > #GInstanceInitFunc here.
1471 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1475 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1477 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1479 return element_class->padtemplates;
1483 * gst_element_class_get_pad_template:
1484 * @element_class: a #GstElementClass to get the pad template of.
1485 * @name: the name of the #GstPadTemplate to get.
1487 * Retrieves a padtemplate from @element_class with the given name.
1488 * > If you use this function in the #GInstanceInitFunc of an object class
1489 * > that has subclasses, make sure to pass the g_class parameter of the
1490 * > #GInstanceInitFunc here.
1492 * Returns: (transfer none) (nullable): the #GstPadTemplate with the
1493 * given name, or %NULL if none was found. No unreferencing is
1497 gst_element_class_get_pad_template (GstElementClass *
1498 element_class, const gchar * name)
1502 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1503 g_return_val_if_fail (name != NULL, NULL);
1505 padlist = element_class->padtemplates;
1508 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1510 if (strcmp (padtempl->name_template, name) == 0)
1513 padlist = g_list_next (padlist);
1519 static GstPadTemplate *
1520 gst_element_class_get_request_pad_template (GstElementClass *
1521 element_class, const gchar * name)
1523 GstPadTemplate *tmpl;
1525 tmpl = gst_element_class_get_pad_template (element_class, name);
1526 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1532 /* get a random pad on element of the given direction.
1533 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1536 gst_element_get_random_pad (GstElement * element,
1537 gboolean need_linked, GstPadDirection dir)
1539 GstPad *result = NULL;
1542 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1546 GST_OBJECT_LOCK (element);
1547 pads = element->srcpads;
1550 GST_OBJECT_LOCK (element);
1551 pads = element->sinkpads;
1554 goto wrong_direction;
1556 for (; pads; pads = g_list_next (pads)) {
1557 GstPad *pad = GST_PAD_CAST (pads->data);
1559 GST_OBJECT_LOCK (pad);
1560 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1561 GST_DEBUG_PAD_NAME (pad));
1563 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1564 /* if we require a linked pad, and it is not linked, continue the
1566 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1567 GST_DEBUG_PAD_NAME (pad));
1568 GST_OBJECT_UNLOCK (pad);
1571 /* found a pad, stop search */
1572 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1573 GST_DEBUG_PAD_NAME (pad));
1574 GST_OBJECT_UNLOCK (pad);
1580 gst_object_ref (result);
1582 GST_OBJECT_UNLOCK (element);
1586 /* ERROR handling */
1589 g_warning ("unknown pad direction %d", dir);
1595 gst_element_default_send_event (GstElement * element, GstEvent * event)
1597 gboolean result = FALSE;
1600 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1601 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK) :
1602 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC);
1605 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1606 "pushing %s event to random %s pad %s:%s",
1607 GST_EVENT_TYPE_NAME (event),
1608 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1609 GST_DEBUG_PAD_NAME (pad));
1611 result = gst_pad_send_event (pad, event);
1612 gst_object_unref (pad);
1614 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1615 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1616 gst_event_unref (event);
1622 * gst_element_send_event:
1623 * @element: a #GstElement to send the event to.
1624 * @event: (transfer full): the #GstEvent to send to the element.
1626 * Sends an event to an element. If the element doesn't implement an
1627 * event handler, the event will be pushed on a random linked sink pad for
1628 * downstream events or a random linked source pad for upstream events.
1630 * This function takes ownership of the provided event so you should
1631 * gst_event_ref() it if you want to reuse the event after this call.
1635 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1636 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1639 gst_element_send_event (GstElement * element, GstEvent * event)
1641 GstElementClass *oclass;
1642 gboolean result = FALSE;
1644 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1645 g_return_val_if_fail (event != NULL, FALSE);
1647 oclass = GST_ELEMENT_GET_CLASS (element);
1649 GST_STATE_LOCK (element);
1650 if (oclass->send_event) {
1651 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1652 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1653 result = oclass->send_event (element, event);
1655 gst_event_unref (event);
1657 GST_STATE_UNLOCK (element);
1664 * @element: a #GstElement to send the event to.
1665 * @rate: The new playback rate
1666 * @format: The format of the seek values
1667 * @flags: The optional seek flags.
1668 * @start_type: The type and flags for the new start position
1669 * @start: The value of the new start position
1670 * @stop_type: The type and flags for the new stop position
1671 * @stop: The value of the new stop position
1673 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1674 * the parameters. The seek event is sent to the element using
1675 * gst_element_send_event().
1679 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1680 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1683 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1684 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1685 GstSeekType stop_type, gint64 stop)
1690 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1693 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1695 result = gst_element_send_event (element, event);
1701 gst_element_default_query (GstElement * element, GstQuery * query)
1703 gboolean result = FALSE;
1706 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1708 result = gst_pad_query (pad, query);
1710 gst_object_unref (pad);
1712 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1714 GstPad *peer = gst_pad_get_peer (pad);
1717 result = gst_pad_query (peer, query);
1719 gst_object_unref (peer);
1721 gst_object_unref (pad);
1728 * gst_element_query:
1729 * @element: a #GstElement to perform the query on.
1730 * @query: (transfer none): the #GstQuery.
1732 * Performs a query on the given element.
1734 * For elements that don't implement a query handler, this function
1735 * forwards the query to a random srcpad or to the peer of a
1736 * random linked sinkpad of this element.
1738 * Please note that some queries might need a running pipeline to work.
1740 * Returns: %TRUE if the query could be performed.
1745 gst_element_query (GstElement * element, GstQuery * query)
1747 GstElementClass *klass;
1748 gboolean res = FALSE;
1750 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1751 g_return_val_if_fail (query != NULL, FALSE);
1753 GST_TRACER_ELEMENT_QUERY_PRE (element, query);
1755 klass = GST_ELEMENT_GET_CLASS (element);
1757 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1758 GST_ELEMENT_NAME (element));
1759 res = klass->query (element, query);
1762 GST_TRACER_ELEMENT_QUERY_POST (element, query, res);
1767 gst_element_post_message_default (GstElement * element, GstMessage * message)
1770 gboolean result = FALSE;
1772 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1773 g_return_val_if_fail (message != NULL, FALSE);
1775 GST_OBJECT_LOCK (element);
1778 if (G_UNLIKELY (bus == NULL))
1781 gst_object_ref (bus);
1782 GST_OBJECT_UNLOCK (element);
1784 /* we release the element lock when posting the message so that any
1785 * (synchronous) message handlers can operate on the element */
1786 result = gst_bus_post (bus, message);
1787 gst_object_unref (bus);
1794 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1795 "not posting message %p: no bus", message);
1796 GST_OBJECT_UNLOCK (element);
1797 gst_message_unref (message);
1803 * gst_element_post_message:
1804 * @element: a #GstElement posting the message
1805 * @message: (transfer full): a #GstMessage to post
1807 * Post a message on the element's #GstBus. This function takes ownership of the
1808 * message; if you want to access the message after this call, you should add an
1809 * additional reference before calling.
1811 * Returns: %TRUE if the message was successfully posted. The function returns
1812 * %FALSE if the element did not have a bus.
1817 gst_element_post_message (GstElement * element, GstMessage * message)
1819 GstElementClass *klass;
1820 gboolean res = FALSE;
1822 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1823 g_return_val_if_fail (message != NULL, FALSE);
1825 GST_TRACER_ELEMENT_POST_MESSAGE_PRE (element, message);
1827 klass = GST_ELEMENT_GET_CLASS (element);
1828 if (klass->post_message)
1829 res = klass->post_message (element, message);
1831 gst_message_unref (message);
1833 GST_TRACER_ELEMENT_POST_MESSAGE_POST (element, res);
1838 * _gst_element_error_printf:
1839 * @format: (allow-none): the printf-like format to use, or %NULL
1841 * This function is only used internally by the gst_element_error() macro.
1843 * Returns: (transfer full) (nullable): a newly allocated string, or
1844 * %NULL if the format was %NULL or ""
1849 _gst_element_error_printf (const gchar * format, ...)
1860 va_start (args, format);
1862 len = __gst_vasprintf (&buffer, format, args);
1873 * gst_element_message_full_with_details:
1874 * @element: a #GstElement to send message from
1875 * @type: the #GstMessageType
1876 * @domain: the GStreamer GError domain this message belongs to
1877 * @code: the GError code belonging to the domain
1878 * @text: (allow-none) (transfer full): an allocated text string to be used
1879 * as a replacement for the default message connected to code,
1881 * @debug: (allow-none) (transfer full): an allocated debug message to be
1882 * used as a replacement for the default debugging information,
1884 * @file: the source code file where the error was generated
1885 * @function: the source code function where the error was generated
1886 * @line: the source code line where the error was generated
1887 * @structure:(transfer full): optional details structure
1889 * Post an error, warning or info message on the bus from inside an element.
1891 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1892 * #GST_MESSAGE_INFO.
1896 void gst_element_message_full_with_details
1897 (GstElement * element, GstMessageType type,
1898 GQuark domain, gint code, gchar * text,
1899 gchar * debug, const gchar * file, const gchar * function, gint line,
1900 GstStructure * structure)
1902 GError *gerror = NULL;
1906 gboolean has_debug = TRUE;
1907 GstMessage *message = NULL;
1910 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1911 g_return_if_fail (GST_IS_ELEMENT (element));
1912 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1913 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1915 /* check if we send the given text or the default error text */
1916 if ((text == NULL) || (text[0] == 0)) {
1917 /* text could have come from g_strdup_printf (""); */
1919 sent_text = gst_error_get_message (domain, code);
1923 /* construct a sent_debug with extra information from source */
1924 if ((debug == NULL) || (debug[0] == 0)) {
1925 /* debug could have come from g_strdup_printf (""); */
1929 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1931 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1932 file, line, function, name, debug);
1934 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1935 file, line, function, name);
1939 /* create gerror and post message */
1940 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1942 gerror = g_error_new_literal (domain, code, sent_text);
1945 case GST_MESSAGE_ERROR:
1947 gst_message_new_error_with_details (GST_OBJECT_CAST (element), gerror,
1948 sent_debug, structure);
1950 case GST_MESSAGE_WARNING:
1952 gst_message_new_warning_with_details (GST_OBJECT_CAST (element),
1953 gerror, sent_debug, structure);
1955 case GST_MESSAGE_INFO:
1957 gst_message_new_info_with_details (GST_OBJECT_CAST (element), gerror,
1958 sent_debug, structure);
1961 g_assert_not_reached ();
1965 gst_element_post_message (element, message);
1967 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1968 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1971 g_error_free (gerror);
1972 g_free (sent_debug);
1977 * gst_element_message_full:
1978 * @element: a #GstElement to send message from
1979 * @type: the #GstMessageType
1980 * @domain: the GStreamer GError domain this message belongs to
1981 * @code: the GError code belonging to the domain
1982 * @text: (allow-none) (transfer full): an allocated text string to be used
1983 * as a replacement for the default message connected to code,
1985 * @debug: (allow-none) (transfer full): an allocated debug message to be
1986 * used as a replacement for the default debugging information,
1988 * @file: the source code file where the error was generated
1989 * @function: the source code function where the error was generated
1990 * @line: the source code line where the error was generated
1992 * Post an error, warning or info message on the bus from inside an element.
1994 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1995 * #GST_MESSAGE_INFO.
1999 void gst_element_message_full
2000 (GstElement * element, GstMessageType type,
2001 GQuark domain, gint code, gchar * text,
2002 gchar * debug, const gchar * file, const gchar * function, gint line)
2004 gst_element_message_full_with_details (element, type, domain, code, text,
2005 debug, file, function, line, NULL);
2009 * gst_element_is_locked_state:
2010 * @element: a #GstElement.
2012 * Checks if the state of an element is locked.
2013 * If the state of an element is locked, state changes of the parent don't
2014 * affect the element.
2015 * This way you can leave currently unused elements inside bins. Just lock their
2016 * state before changing the state from #GST_STATE_NULL.
2020 * Returns: %TRUE, if the element's state is locked.
2023 gst_element_is_locked_state (GstElement * element)
2027 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2029 GST_OBJECT_LOCK (element);
2030 result = GST_ELEMENT_IS_LOCKED_STATE (element);
2031 GST_OBJECT_UNLOCK (element);
2037 * gst_element_set_locked_state:
2038 * @element: a #GstElement
2039 * @locked_state: %TRUE to lock the element's state
2041 * Locks the state of an element, so state changes of the parent don't affect
2042 * this element anymore.
2046 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
2047 * or the elements state-locking needed no change.
2050 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
2054 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2056 GST_OBJECT_LOCK (element);
2057 old = GST_ELEMENT_IS_LOCKED_STATE (element);
2059 if (G_UNLIKELY (old == locked_state))
2063 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
2064 GST_ELEMENT_NAME (element));
2065 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2067 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
2068 GST_ELEMENT_NAME (element));
2069 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
2071 GST_OBJECT_UNLOCK (element);
2077 GST_CAT_DEBUG (GST_CAT_STATES,
2078 "elements %s was already in locked state %d",
2079 GST_ELEMENT_NAME (element), old);
2080 GST_OBJECT_UNLOCK (element);
2087 * gst_element_sync_state_with_parent:
2088 * @element: a #GstElement.
2090 * Tries to change the state of the element to the same as its parent.
2091 * If this function returns %FALSE, the state of element is undefined.
2093 * Returns: %TRUE, if the element's state could be synced to the parent's state.
2098 gst_element_sync_state_with_parent (GstElement * element)
2102 GstStateChangeReturn ret;
2104 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
2106 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
2107 GstState parent_current, parent_pending;
2109 GST_OBJECT_LOCK (parent);
2110 parent_current = GST_STATE (parent);
2111 parent_pending = GST_STATE_PENDING (parent);
2112 GST_OBJECT_UNLOCK (parent);
2114 /* set to pending if there is one, else we set it to the current state of
2116 if (parent_pending != GST_STATE_VOID_PENDING)
2117 target = parent_pending;
2119 target = parent_current;
2121 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2122 "syncing state (%s) to parent %s %s (%s, %s)",
2123 gst_element_state_get_name (GST_STATE (element)),
2124 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
2125 gst_element_state_get_name (parent_current),
2126 gst_element_state_get_name (parent_pending));
2128 ret = gst_element_set_state (element, target);
2129 if (ret == GST_STATE_CHANGE_FAILURE)
2132 gst_object_unref (parent);
2136 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2143 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2144 "syncing state failed (%s)",
2145 gst_element_state_change_return_get_name (ret));
2146 gst_object_unref (parent);
2152 static GstStateChangeReturn
2153 gst_element_get_state_func (GstElement * element,
2154 GstState * state, GstState * pending, GstClockTime timeout)
2156 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2157 GstState old_pending;
2159 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2160 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2162 GST_OBJECT_LOCK (element);
2163 ret = GST_STATE_RETURN (element);
2164 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2165 gst_element_state_change_return_get_name (ret));
2167 /* we got an error, report immediately */
2168 if (ret == GST_STATE_CHANGE_FAILURE)
2171 /* we got no_preroll, report immediately */
2172 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2175 /* no need to wait async if we are not async */
2176 if (ret != GST_STATE_CHANGE_ASYNC)
2179 old_pending = GST_STATE_PENDING (element);
2180 if (old_pending != GST_STATE_VOID_PENDING) {
2184 /* get cookie to detect state changes during waiting */
2185 cookie = element->state_cookie;
2187 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2188 "waiting for element to commit state");
2190 /* we have a pending state change, wait for it to complete */
2191 if (timeout != GST_CLOCK_TIME_NONE) {
2193 /* make timeout absolute */
2194 end_time = g_get_monotonic_time () + (timeout / 1000);
2195 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2197 GST_STATE_WAIT (element);
2202 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2203 /* timeout triggered */
2204 ret = GST_STATE_CHANGE_ASYNC;
2206 if (cookie != element->state_cookie)
2209 /* could be success or failure */
2210 if (old_pending == GST_STATE (element)) {
2211 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2212 ret = GST_STATE_CHANGE_SUCCESS;
2214 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2215 ret = GST_STATE_CHANGE_FAILURE;
2218 /* if nothing is pending anymore we can return SUCCESS */
2219 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2220 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2221 ret = GST_STATE_CHANGE_SUCCESS;
2227 *state = GST_STATE (element);
2229 *pending = GST_STATE_PENDING (element);
2231 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2232 "state current: %s, pending: %s, result: %s",
2233 gst_element_state_get_name (GST_STATE (element)),
2234 gst_element_state_get_name (GST_STATE_PENDING (element)),
2235 gst_element_state_change_return_get_name (ret));
2236 GST_OBJECT_UNLOCK (element);
2243 *state = GST_STATE_VOID_PENDING;
2245 *pending = GST_STATE_VOID_PENDING;
2247 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2249 GST_OBJECT_UNLOCK (element);
2251 return GST_STATE_CHANGE_FAILURE;
2256 * gst_element_get_state:
2257 * @element: a #GstElement to get the state of.
2258 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2260 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2261 * state. Can be %NULL.
2262 * @timeout: a #GstClockTime to specify the timeout for an async
2263 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2265 * Gets the state of the element.
2267 * For elements that performed an ASYNC state change, as reported by
2268 * gst_element_set_state(), this function will block up to the
2269 * specified timeout value for the state change to complete.
2270 * If the element completes the state change or goes into
2271 * an error, this function returns immediately with a return value of
2272 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2274 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2275 * returns the current and pending state immediately.
2277 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2278 * successfully changed its state but is not able to provide data yet.
2279 * This mostly happens for live sources that only produce data in
2280 * %GST_STATE_PLAYING. While the state change return is equivalent to
2281 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2282 * some sink elements might not be able to complete their state change because
2283 * an element is not producing data to complete the preroll. When setting the
2284 * element to playing, the preroll will complete and playback will start.
2286 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2287 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2288 * element is still performing a state change or
2289 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2293 GstStateChangeReturn
2294 gst_element_get_state (GstElement * element,
2295 GstState * state, GstState * pending, GstClockTime timeout)
2297 GstElementClass *oclass;
2298 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2300 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2302 oclass = GST_ELEMENT_GET_CLASS (element);
2304 if (oclass->get_state)
2305 result = (oclass->get_state) (element, state, pending, timeout);
2311 * gst_element_abort_state:
2312 * @element: a #GstElement to abort the state of.
2314 * Abort the state change of the element. This function is used
2315 * by elements that do asynchronous state changes and find out
2316 * something is wrong.
2318 * This function should be called with the STATE_LOCK held.
2323 gst_element_abort_state (GstElement * element)
2327 #ifndef GST_DISABLE_GST_DEBUG
2331 g_return_if_fail (GST_IS_ELEMENT (element));
2333 GST_OBJECT_LOCK (element);
2334 pending = GST_STATE_PENDING (element);
2336 if (pending == GST_STATE_VOID_PENDING ||
2337 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2338 goto nothing_aborted;
2340 #ifndef GST_DISABLE_GST_DEBUG
2341 old_state = GST_STATE (element);
2343 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2344 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2345 gst_element_state_get_name (pending));
2349 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2351 GST_STATE_BROADCAST (element);
2352 GST_OBJECT_UNLOCK (element);
2358 GST_OBJECT_UNLOCK (element);
2363 /* Not static because GstBin has manual state handling too */
2365 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2366 GstState newstate, GstState pending)
2368 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2369 GstMessage *message;
2371 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2372 "notifying about state-changed %s to %s (%s pending)",
2373 gst_element_state_get_name (oldstate),
2374 gst_element_state_get_name (newstate),
2375 gst_element_state_get_name (pending));
2377 if (klass->state_changed)
2378 klass->state_changed (element, oldstate, newstate, pending);
2380 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2381 oldstate, newstate, pending);
2382 gst_element_post_message (element, message);
2386 * gst_element_continue_state:
2387 * @element: a #GstElement to continue the state change of.
2388 * @ret: The previous state return value
2390 * Commit the state change of the element and proceed to the next
2391 * pending state if any. This function is used
2392 * by elements that do asynchronous state changes.
2393 * The core will normally call this method automatically when an
2394 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2396 * If after calling this method the element still has not reached
2397 * the pending state, the next state change is performed.
2399 * This method is used internally and should normally not be called by plugins
2402 * Returns: The result of the commit state change.
2406 GstStateChangeReturn
2407 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2409 GstStateChangeReturn old_ret;
2410 GstState old_state, old_next;
2411 GstState current, next, pending;
2412 GstStateChange transition;
2414 GST_OBJECT_LOCK (element);
2415 old_ret = GST_STATE_RETURN (element);
2416 GST_STATE_RETURN (element) = ret;
2417 pending = GST_STATE_PENDING (element);
2419 /* check if there is something to commit */
2420 if (pending == GST_STATE_VOID_PENDING)
2421 goto nothing_pending;
2423 old_state = GST_STATE (element);
2424 /* this is the state we should go to next */
2425 old_next = GST_STATE_NEXT (element);
2426 /* update current state */
2427 current = GST_STATE (element) = old_next;
2429 /* see if we reached the final state */
2430 if (pending == current)
2433 next = GST_STATE_GET_NEXT (current, pending);
2434 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2436 GST_STATE_NEXT (element) = next;
2438 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2439 GST_OBJECT_UNLOCK (element);
2441 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2442 "committing state from %s to %s, pending %s, next %s",
2443 gst_element_state_get_name (old_state),
2444 gst_element_state_get_name (old_next),
2445 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2447 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2449 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2450 "continue state change %s to %s, final %s",
2451 gst_element_state_get_name (current),
2452 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2454 ret = gst_element_change_state (element, transition);
2460 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2461 GST_OBJECT_UNLOCK (element);
2466 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2467 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2469 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2470 "completed state change to %s", gst_element_state_get_name (pending));
2471 GST_OBJECT_UNLOCK (element);
2473 /* don't post silly messages with the same state. This can happen
2474 * when an element state is changed to what it already was. For bins
2475 * this can be the result of a lost state, which we check with the
2476 * previous return value.
2477 * We do signal the cond though as a _get_state() might be blocking
2479 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2480 _priv_gst_element_state_changed (element, old_state, old_next,
2481 GST_STATE_VOID_PENDING);
2483 GST_STATE_BROADCAST (element);
2490 * gst_element_lost_state:
2491 * @element: a #GstElement the state is lost of
2493 * Brings the element to the lost state. The current state of the
2494 * element is copied to the pending state so that any call to
2495 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2497 * An ASYNC_START message is posted. If the element was PLAYING, it will
2498 * go to PAUSED. The element will be restored to its PLAYING state by
2499 * the parent pipeline when it prerolls again.
2501 * This is mostly used for elements that lost their preroll buffer
2502 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2503 * they will go to their pending state again when a new preroll buffer is
2504 * queued. This function can only be called when the element is currently
2505 * not in error or an async state change.
2507 * This function is used internally and should normally not be called from
2508 * plugins or applications.
2511 gst_element_lost_state (GstElement * element)
2513 GstState old_state, new_state;
2514 GstMessage *message;
2516 g_return_if_fail (GST_IS_ELEMENT (element));
2518 GST_OBJECT_LOCK (element);
2519 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2522 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2523 goto only_async_start;
2525 old_state = GST_STATE (element);
2527 /* when we were PLAYING, the new state is PAUSED. We will also not
2528 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2529 * when we preroll. */
2530 if (old_state > GST_STATE_PAUSED)
2531 new_state = GST_STATE_PAUSED;
2533 new_state = old_state;
2535 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2536 "lost state of %s to %s", gst_element_state_get_name (old_state),
2537 gst_element_state_get_name (new_state));
2539 GST_STATE (element) = new_state;
2540 GST_STATE_NEXT (element) = new_state;
2541 GST_STATE_PENDING (element) = new_state;
2542 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2543 GST_OBJECT_UNLOCK (element);
2545 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2547 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2548 gst_element_post_message (element, message);
2554 GST_OBJECT_UNLOCK (element);
2559 GST_OBJECT_UNLOCK (element);
2561 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2562 gst_element_post_message (element, message);
2568 * gst_element_set_state:
2569 * @element: a #GstElement to change state of.
2570 * @state: the element's new #GstState.
2572 * Sets the state of the element. This function will try to set the
2573 * requested state by going through all the intermediary states and calling
2574 * the class's state change function for each.
2576 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2577 * element will perform the remainder of the state change asynchronously in
2579 * An application can use gst_element_get_state() to wait for the completion
2580 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2581 * %GST_MESSAGE_STATE_CHANGED on the bus.
2583 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2584 * #GST_STATE_CHANGE_ASYNC.
2586 * Returns: Result of the state change using #GstStateChangeReturn.
2590 GstStateChangeReturn
2591 gst_element_set_state (GstElement * element, GstState state)
2593 GstElementClass *oclass;
2594 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2596 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2598 oclass = GST_ELEMENT_GET_CLASS (element);
2600 if (oclass->set_state)
2601 result = (oclass->set_state) (element, state);
2607 * default set state function, calculates the next state based
2608 * on current state and calls the change_state function
2610 static GstStateChangeReturn
2611 gst_element_set_state_func (GstElement * element, GstState state)
2613 GstState current, next, old_pending;
2614 GstStateChangeReturn ret;
2615 GstStateChange transition;
2616 GstStateChangeReturn old_ret;
2618 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2620 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2621 gst_element_state_get_name (state));
2623 /* state lock is taken to protect the set_state() and get_state()
2624 * procedures, it does not lock any variables. */
2625 GST_STATE_LOCK (element);
2627 /* now calculate how to get to the new state */
2628 GST_OBJECT_LOCK (element);
2629 old_ret = GST_STATE_RETURN (element);
2630 /* previous state change returned an error, remove all pending
2631 * and next states */
2632 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2633 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2634 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2635 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2638 current = GST_STATE (element);
2639 next = GST_STATE_NEXT (element);
2640 old_pending = GST_STATE_PENDING (element);
2642 /* this is the (new) state we should go to. TARGET is the last state we set on
2644 if (state != GST_STATE_TARGET (element)) {
2645 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2646 "setting target state to %s", gst_element_state_get_name (state));
2647 GST_STATE_TARGET (element) = state;
2648 /* increment state cookie so that we can track each state change. We only do
2649 * this if this is actually a new state change. */
2650 element->state_cookie++;
2652 GST_STATE_PENDING (element) = state;
2654 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2655 "current %s, old_pending %s, next %s, old return %s",
2656 gst_element_state_get_name (current),
2657 gst_element_state_get_name (old_pending),
2658 gst_element_state_get_name (next),
2659 gst_element_state_change_return_get_name (old_ret));
2661 /* if the element was busy doing a state change, we just update the
2662 * target state, it'll get to it async then. */
2663 if (old_pending != GST_STATE_VOID_PENDING) {
2664 /* upwards state change will happen ASYNC */
2665 if (old_pending <= state)
2667 /* element is going to this state already */
2668 else if (next == state)
2670 /* element was performing an ASYNC upward state change and
2671 * we request to go downward again. Start from the next pending
2673 else if (next > state
2674 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2678 next = GST_STATE_GET_NEXT (current, state);
2679 /* now we store the next state */
2680 GST_STATE_NEXT (element) = next;
2681 /* mark busy, we need to check that there is actually a state change
2682 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2683 * the default element change_state function has no way to know what the
2684 * old value was... could consider this a FIXME...*/
2685 if (current != next)
2686 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2688 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2690 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2691 "%s: setting state from %s to %s",
2692 (next != state ? "intermediate" : "final"),
2693 gst_element_state_get_name (current), gst_element_state_get_name (next));
2695 /* now signal any waiters, they will error since the cookie was incremented */
2696 GST_STATE_BROADCAST (element);
2698 GST_OBJECT_UNLOCK (element);
2700 ret = gst_element_change_state (element, transition);
2702 GST_STATE_UNLOCK (element);
2704 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2705 gst_element_state_change_return_get_name (ret));
2711 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2712 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2713 "element was busy with async state change");
2714 GST_OBJECT_UNLOCK (element);
2716 GST_STATE_UNLOCK (element);
2718 return GST_STATE_CHANGE_ASYNC;
2723 * gst_element_change_state:
2724 * @element: a #GstElement
2725 * @transition: the requested transition
2727 * Perform @transition on @element.
2729 * This function must be called with STATE_LOCK held and is mainly used
2732 * Returns: the #GstStateChangeReturn of the state transition.
2734 GstStateChangeReturn
2735 gst_element_change_state (GstElement * element, GstStateChange transition)
2737 GstElementClass *oclass;
2738 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2740 oclass = GST_ELEMENT_GET_CLASS (element);
2742 GST_TRACER_ELEMENT_CHANGE_STATE_PRE (element, transition);
2744 /* call the state change function so it can set the state */
2745 if (oclass->change_state)
2746 ret = (oclass->change_state) (element, transition);
2748 ret = GST_STATE_CHANGE_FAILURE;
2750 GST_TRACER_ELEMENT_CHANGE_STATE_POST (element, transition, ret);
2753 case GST_STATE_CHANGE_FAILURE:
2754 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2755 "have FAILURE change_state return");
2756 /* state change failure */
2757 gst_element_abort_state (element);
2759 case GST_STATE_CHANGE_ASYNC:
2763 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2764 "element will change state ASYNC");
2766 target = GST_STATE_TARGET (element);
2768 if (target > GST_STATE_READY)
2771 /* else we just continue the state change downwards */
2772 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2773 "forcing commit state %s <= %s",
2774 gst_element_state_get_name (target),
2775 gst_element_state_get_name (GST_STATE_READY));
2777 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2780 case GST_STATE_CHANGE_SUCCESS:
2781 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2782 "element changed state SUCCESS");
2783 /* we can commit the state now which will proceeed to
2785 ret = gst_element_continue_state (element, ret);
2787 case GST_STATE_CHANGE_NO_PREROLL:
2788 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2789 "element changed state NO_PREROLL");
2790 /* we can commit the state now which will proceeed to
2792 ret = gst_element_continue_state (element, ret);
2795 goto invalid_return;
2798 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2803 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2811 GST_OBJECT_LOCK (element);
2812 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2813 g_critical ("%s: unknown return value %d from a state change function",
2814 GST_ELEMENT_NAME (element), ret);
2816 /* we are in error now */
2817 ret = GST_STATE_CHANGE_FAILURE;
2818 GST_STATE_RETURN (element) = ret;
2819 GST_OBJECT_UNLOCK (element);
2825 /* gst_iterator_fold functions for pads_activate
2826 * Stop the iterator if activating one pad failed, but only if that pad
2827 * has not been removed from the element. */
2829 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2831 GstPad *pad = g_value_get_object (vpad);
2832 gboolean cont = TRUE;
2834 if (!gst_pad_set_active (pad, *active)) {
2835 if (GST_PAD_PARENT (pad) != NULL) {
2837 g_value_set_boolean (ret, FALSE);
2844 /* returns false on error or early cutout of the fold, true if all
2845 * pads in @iter were (de)activated successfully. */
2847 iterator_activate_fold_with_resync (GstIterator * iter,
2848 GstIteratorFoldFunction func, gpointer user_data)
2850 GstIteratorResult ires;
2853 /* no need to unset this later, it's just a boolean */
2854 g_value_init (&ret, G_TYPE_BOOLEAN);
2855 g_value_set_boolean (&ret, TRUE);
2858 ires = gst_iterator_fold (iter, func, &ret, user_data);
2860 case GST_ITERATOR_RESYNC:
2861 /* need to reset the result again */
2862 g_value_set_boolean (&ret, TRUE);
2863 gst_iterator_resync (iter);
2865 case GST_ITERATOR_DONE:
2866 /* all pads iterated, return collected value */
2869 /* iterator returned _ERROR or premature end with _OK,
2870 * mark an error and exit */
2871 g_value_set_boolean (&ret, FALSE);
2876 /* return collected value */
2877 return g_value_get_boolean (&ret);
2880 /* is called with STATE_LOCK
2882 * Pads are activated from source pads to sinkpads.
2885 gst_element_pads_activate (GstElement * element, gboolean active)
2890 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2891 "%s pads", active ? "activate" : "deactivate");
2893 iter = gst_element_iterate_src_pads (element);
2895 iterator_activate_fold_with_resync (iter,
2896 (GstIteratorFoldFunction) activate_pads, &active);
2897 gst_iterator_free (iter);
2898 if (G_UNLIKELY (!res))
2901 iter = gst_element_iterate_sink_pads (element);
2903 iterator_activate_fold_with_resync (iter,
2904 (GstIteratorFoldFunction) activate_pads, &active);
2905 gst_iterator_free (iter);
2906 if (G_UNLIKELY (!res))
2909 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2910 "pad %sactivation successful", active ? "" : "de");
2917 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2918 "pad %sactivation failed", active ? "" : "de");
2923 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2924 "sink pads_activate failed");
2929 /* is called with STATE_LOCK */
2930 static GstStateChangeReturn
2931 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2933 GstState state, next;
2934 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2936 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2938 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2939 next = GST_STATE_TRANSITION_NEXT (transition);
2941 /* if the element already is in the given state, we just return success */
2942 if (next == GST_STATE_VOID_PENDING || state == next)
2945 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2946 "default handler tries setting state from %s to %s (%04x)",
2947 gst_element_state_get_name (state),
2948 gst_element_state_get_name (next), transition);
2950 switch (transition) {
2951 case GST_STATE_CHANGE_NULL_TO_READY:
2953 case GST_STATE_CHANGE_READY_TO_PAUSED:
2954 if (!gst_element_pads_activate (element, TRUE)) {
2955 result = GST_STATE_CHANGE_FAILURE;
2958 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2960 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2962 case GST_STATE_CHANGE_PAUSED_TO_READY:
2963 case GST_STATE_CHANGE_READY_TO_NULL:{
2966 /* deactivate pads in both cases, since they are activated on
2967 ready->paused but the element might not have made it to paused */
2968 if (!gst_element_pads_activate (element, FALSE)) {
2969 result = GST_STATE_CHANGE_FAILURE;
2972 /* Remove all non-persistent contexts */
2973 GST_OBJECT_LOCK (element);
2974 for (l = element->contexts; l;) {
2975 GstContext *context = l->data;
2977 if (!gst_context_is_persistent (context)) {
2980 gst_context_unref (context);
2982 element->contexts = g_list_delete_link (element->contexts, l);
2988 GST_OBJECT_UNLOCK (element);
2992 /* this will catch real but unhandled state changes;
2993 * can only be caused by:
2994 * - a new state was added
2995 * - somehow the element was asked to jump across an intermediate state
2997 g_warning ("Unhandled state change from %s to %s",
2998 gst_element_state_get_name (state),
2999 gst_element_state_get_name (next));
3006 GST_OBJECT_LOCK (element);
3007 result = GST_STATE_RETURN (element);
3008 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
3009 "element is already in the %s state",
3010 gst_element_state_get_name (state));
3011 GST_OBJECT_UNLOCK (element);
3018 * gst_element_get_factory:
3019 * @element: a #GstElement to request the element factory of.
3021 * Retrieves the factory that was used to create this element.
3023 * Returns: (transfer none): the #GstElementFactory used for creating this
3024 * element. no refcounting is needed.
3027 gst_element_get_factory (GstElement * element)
3029 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3031 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
3035 gst_element_dispose (GObject * object)
3037 GstElement *element = GST_ELEMENT_CAST (object);
3040 GstElementClass *oclass;
3043 oclass = GST_ELEMENT_GET_CLASS (element);
3045 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p dispose", element);
3047 if (GST_STATE (element) != GST_STATE_NULL)
3050 /* start by releasing all request pads, this might also remove some dynamic
3052 walk = element->pads;
3054 GstPad *pad = GST_PAD_CAST (walk->data);
3058 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
3059 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
3060 == GST_PAD_REQUEST) {
3061 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3062 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3063 oclass->release_pad (element, pad);
3065 /* in case the release_pad function removed the next pad too */
3066 if (walk && g_list_position (element->pads, walk) == -1)
3067 walk = element->pads;
3070 /* remove the remaining pads */
3071 while (element->pads) {
3072 GstPad *pad = GST_PAD_CAST (element->pads->data);
3073 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
3074 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3075 if (!gst_element_remove_pad (element, pad)) {
3076 /* only happens when someone unparented our pad.. */
3077 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
3082 GST_OBJECT_LOCK (element);
3083 clock_p = &element->clock;
3084 bus_p = &element->bus;
3085 gst_object_replace ((GstObject **) clock_p, NULL);
3086 gst_object_replace ((GstObject **) bus_p, NULL);
3087 g_list_free_full (element->contexts, (GDestroyNotify) gst_context_unref);
3088 GST_OBJECT_UNLOCK (element);
3090 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p parent class dispose",
3093 G_OBJECT_CLASS (parent_class)->dispose (object);
3102 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
3104 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
3106 "You need to explicitly set elements to the NULL state before\n"
3107 "dropping the final reference, to allow them to clean up.\n"
3108 "This problem may also be caused by a refcounting bug in the\n"
3109 "application or some element.\n",
3110 GST_OBJECT_NAME (element),
3111 gst_element_state_get_name (GST_STATE (element)),
3112 is_locked ? " (locked)" : "");
3118 gst_element_finalize (GObject * object)
3120 GstElement *element = GST_ELEMENT_CAST (object);
3122 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize", element);
3124 g_cond_clear (&element->state_cond);
3125 g_rec_mutex_clear (&element->state_lock);
3127 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "%p finalize parent",
3130 G_OBJECT_CLASS (parent_class)->finalize (object);
3134 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3138 g_return_if_fail (GST_IS_ELEMENT (element));
3140 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3142 GST_OBJECT_LOCK (element);
3143 bus_p = &GST_ELEMENT_BUS (element);
3144 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3145 GST_OBJECT_UNLOCK (element);
3149 * gst_element_set_bus:
3150 * @element: a #GstElement to set the bus of.
3151 * @bus: (transfer none): the #GstBus to set.
3153 * Sets the bus of the element. Increases the refcount on the bus.
3154 * For internal use only, unless you're testing elements.
3159 gst_element_set_bus (GstElement * element, GstBus * bus)
3161 GstElementClass *oclass;
3163 g_return_if_fail (GST_IS_ELEMENT (element));
3165 oclass = GST_ELEMENT_GET_CLASS (element);
3167 if (oclass->set_bus)
3168 oclass->set_bus (element, bus);
3172 * gst_element_get_bus:
3173 * @element: a #GstElement to get the bus of.
3175 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3176 * bus for the application.
3178 * Returns: (transfer full): the element's #GstBus. unref after usage.
3183 gst_element_get_bus (GstElement * element)
3185 GstBus *result = NULL;
3187 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3189 GST_OBJECT_LOCK (element);
3190 if ((result = GST_ELEMENT_BUS (element)))
3191 gst_object_ref (result);
3192 GST_OBJECT_UNLOCK (element);
3194 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3201 gst_element_set_context_default (GstElement * element, GstContext * context)
3203 const gchar *context_type;
3206 g_return_if_fail (GST_IS_CONTEXT (context));
3207 context_type = gst_context_get_context_type (context);
3208 g_return_if_fail (context_type != NULL);
3210 GST_OBJECT_LOCK (element);
3211 for (l = element->contexts; l; l = l->next) {
3212 GstContext *tmp = l->data;
3213 const gchar *tmp_type = gst_context_get_context_type (tmp);
3215 /* Always store newest context but never replace
3216 * a persistent one by a non-persistent one */
3217 if (g_strcmp0 (context_type, tmp_type) == 0 &&
3218 (gst_context_is_persistent (context) ||
3219 !gst_context_is_persistent (tmp))) {
3220 gst_context_replace ((GstContext **) & l->data, context);
3224 /* Not found? Add */
3227 g_list_prepend (element->contexts, gst_context_ref (context));
3229 GST_OBJECT_UNLOCK (element);
3233 * gst_element_set_context:
3234 * @element: a #GstElement to set the context of.
3235 * @context: (transfer none): the #GstContext to set.
3237 * Sets the context of the element. Increases the refcount of the context.
3242 gst_element_set_context (GstElement * element, GstContext * context)
3244 GstElementClass *oclass;
3246 g_return_if_fail (GST_IS_ELEMENT (element));
3247 g_return_if_fail (GST_IS_CONTEXT (context));
3249 oclass = GST_ELEMENT_GET_CLASS (element);
3251 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3252 "set context %p %" GST_PTR_FORMAT, context,
3253 gst_context_get_structure (context));
3255 if (oclass->set_context)
3256 oclass->set_context (element, context);
3260 * gst_element_get_contexts:
3261 * @element: a #GstElement to set the context of.
3263 * Gets the contexts set on the element.
3267 * Returns: (element-type Gst.Context) (transfer full): List of #GstContext
3272 gst_element_get_contexts (GstElement * element)
3276 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3278 GST_OBJECT_LOCK (element);
3279 ret = g_list_copy_deep (element->contexts, (GCopyFunc) gst_context_ref, NULL);
3280 GST_OBJECT_UNLOCK (element);
3286 _match_context_type (GstContext * c1, const gchar * context_type)
3288 const gchar *c1_type;
3290 c1_type = gst_context_get_context_type (c1);
3292 return g_strcmp0 (c1_type, context_type);
3296 * gst_element_get_context_unlocked:
3297 * @element: a #GstElement to get the context of.
3298 * @context_type: a name of a context to retrieve
3300 * Gets the context with @context_type set on the element or NULL.
3302 * Returns: (transfer full): A #GstContext or NULL
3307 gst_element_get_context_unlocked (GstElement * element,
3308 const gchar * context_type)
3310 GstContext *ret = NULL;
3313 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3316 g_list_find_custom (element->contexts, context_type,
3317 (GCompareFunc) _match_context_type);
3318 if (node && node->data)
3319 ret = gst_context_ref (node->data);
3325 * gst_element_get_context:
3326 * @element: a #GstElement to get the context of.
3327 * @context_type: a name of a context to retrieve
3329 * Gets the context with @context_type set on the element or NULL.
3333 * Returns: (transfer full): A #GstContext or NULL
3338 gst_element_get_context (GstElement * element, const gchar * context_type)
3340 GstContext *ret = NULL;
3342 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3344 GST_OBJECT_LOCK (element);
3345 ret = gst_element_get_context_unlocked (element, context_type);
3346 GST_OBJECT_UNLOCK (element);
3352 gst_element_property_post_notify_msg (GstElement * element, GObject * obj,
3353 GParamSpec * pspec, gboolean include_value)
3355 GValue val = G_VALUE_INIT;
3358 GST_LOG_OBJECT (element, "property '%s' of object %" GST_PTR_FORMAT " has "
3359 "changed, posting message with%s value", pspec->name, obj,
3360 include_value ? "" : "out");
3362 if (include_value && (pspec->flags & G_PARAM_READABLE) != 0) {
3363 g_value_init (&val, pspec->value_type);
3364 g_object_get_property (obj, pspec->name, &val);
3369 gst_element_post_message (element,
3370 gst_message_new_property_notify (GST_OBJECT_CAST (obj), pspec->name, v));
3374 gst_element_property_deep_notify_cb (GstElement * element, GObject * prop_obj,
3375 GParamSpec * pspec, gpointer user_data)
3377 gboolean include_value = GPOINTER_TO_INT (user_data);
3379 gst_element_property_post_notify_msg (element, prop_obj, pspec,
3384 gst_element_property_notify_cb (GObject * obj, GParamSpec * pspec,
3387 gboolean include_value = GPOINTER_TO_INT (user_data);
3389 gst_element_property_post_notify_msg (GST_ELEMENT_CAST (obj), obj, pspec,
3394 * gst_element_add_property_notify_watch:
3395 * @element: a #GstElement to watch for property changes
3396 * @property_name: (allow-none): name of property to watch for changes, or
3397 * NULL to watch all properties
3398 * @include_value: whether to include the new property value in the message
3400 * Returns: a watch id, which can be used in connection with
3401 * gst_element_remove_property_notify_watch() to remove the watch again.
3406 gst_element_add_property_notify_watch (GstElement * element,
3407 const gchar * property_name, gboolean include_value)
3413 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3415 sep = (property_name != NULL) ? "::" : NULL;
3416 signal_name = g_strconcat ("notify", sep, property_name, NULL);
3417 id = g_signal_connect (element, signal_name,
3418 G_CALLBACK (gst_element_property_notify_cb),
3419 GINT_TO_POINTER (include_value));
3420 g_free (signal_name);
3426 * gst_element_add_property_deep_notify_watch:
3427 * @element: a #GstElement to watch (recursively) for property changes
3428 * @property_name: (allow-none): name of property to watch for changes, or
3429 * NULL to watch all properties
3430 * @include_value: whether to include the new property value in the message
3432 * Returns: a watch id, which can be used in connection with
3433 * gst_element_remove_property_notify_watch() to remove the watch again.
3438 gst_element_add_property_deep_notify_watch (GstElement * element,
3439 const gchar * property_name, gboolean include_value)
3445 g_return_val_if_fail (GST_IS_ELEMENT (element), 0);
3447 sep = (property_name != NULL) ? "::" : NULL;
3448 signal_name = g_strconcat ("deep-notify", sep, property_name, NULL);
3449 id = g_signal_connect (element, signal_name,
3450 G_CALLBACK (gst_element_property_deep_notify_cb),
3451 GINT_TO_POINTER (include_value));
3452 g_free (signal_name);
3458 * gst_element_remove_property_notify_watch:
3459 * @element: a #GstElement being watched for property changes
3460 * @watch_id: watch id to remove
3465 gst_element_remove_property_notify_watch (GstElement * element, gulong watch_id)
3467 g_signal_handler_disconnect (element, watch_id);
3472 GstElement *element;
3473 GstElementCallAsyncFunc func;
3475 GDestroyNotify destroy_notify;
3476 } GstElementCallAsyncData;
3479 gst_element_call_async_func (gpointer data, gpointer user_data)
3481 GstElementCallAsyncData *async_data = data;
3483 async_data->func (async_data->element, async_data->user_data);
3484 if (async_data->destroy_notify)
3485 async_data->destroy_notify (async_data->user_data);
3486 gst_object_unref (async_data->element);
3487 g_free (async_data);
3491 * gst_element_call_async:
3492 * @element: a #GstElement
3493 * @func: Function to call asynchronously from another thread
3494 * @user_data: Data to pass to @func
3495 * @destroy_notify: GDestroyNotify for @user_data
3497 * Calls @func from another thread and passes @user_data to it. This is to be
3498 * used for cases when a state change has to be performed from a streaming
3499 * thread, directly via gst_element_set_state() or indirectly e.g. via SEEK
3502 * Calling those functions directly from the streaming thread will cause
3503 * deadlocks in many situations, as they might involve waiting for the
3504 * streaming thread to shut down from this very streaming thread.
3511 gst_element_call_async (GstElement * element, GstElementCallAsyncFunc func,
3512 gpointer user_data, GDestroyNotify destroy_notify)
3514 GstElementCallAsyncData *async_data;
3516 g_return_if_fail (GST_IS_ELEMENT (element));
3518 async_data = g_new0 (GstElementCallAsyncData, 1);
3519 async_data->element = gst_object_ref (element);
3520 async_data->func = func;
3521 async_data->user_data = user_data;
3522 async_data->destroy_notify = destroy_notify;
3524 g_thread_pool_push (gst_element_pool, async_data, NULL);
3528 _priv_gst_element_cleanup (void)
3530 if (gst_element_pool) {
3531 g_thread_pool_free (gst_element_pool, FALSE, TRUE);
3532 gst_element_setup_thread_pool ();
3537 gst_make_element_message_details (const char *name, ...)
3539 GstStructure *structure;
3545 va_start (varargs, name);
3546 structure = gst_structure_new_valist ("details", name, varargs);