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.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * Elements can have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate or
47 * gst_element_get_request_pad() with the template name such as "src_\%u".
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 slection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
79 * Last reviewed on 2012-03-28 (0.11.3)
82 #include "gst_private.h"
85 #include <gobject/gvaluecollector.h>
87 #include "gstelement.h"
88 #include "gstelementmetadata.h"
89 #include "gstenumtypes.h"
97 #include "gst-i18n-lib.h"
98 #include "glib-compat-private.h"
100 #ifndef GST_DISABLE_GST_DEBUG
101 #include "printf/printf.h"
104 /* Element signals and args */
120 static void gst_element_class_init (GstElementClass * klass);
121 static void gst_element_init (GstElement * element);
122 static void gst_element_base_class_init (gpointer g_class);
123 static void gst_element_base_class_finalize (gpointer g_class);
125 static void gst_element_dispose (GObject * object);
126 static void gst_element_finalize (GObject * object);
128 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
129 GstStateChange transition);
130 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
131 GstState * state, GstState * pending, GstClockTime timeout);
132 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
134 static gboolean gst_element_set_clock_func (GstElement * element,
136 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
137 static gboolean gst_element_post_message_default (GstElement * element,
138 GstMessage * message);
139 static void gst_element_set_context_func (GstElement * element,
140 GstContext * context);
142 static gboolean gst_element_default_send_event (GstElement * element,
144 static gboolean gst_element_default_query (GstElement * element,
147 static GstPadTemplate
148 * gst_element_class_get_request_pad_template (GstElementClass *
149 element_class, const gchar * name);
151 static GstObjectClass *parent_class = NULL;
152 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
154 /* this is used in gstelementfactory.c:gst_element_register() */
155 GQuark __gst_elementclass_factory = 0;
158 gst_element_get_type (void)
160 static volatile gsize gst_element_type = 0;
162 if (g_once_init_enter (&gst_element_type)) {
164 static const GTypeInfo element_info = {
165 sizeof (GstElementClass),
166 gst_element_base_class_init,
167 gst_element_base_class_finalize,
168 (GClassInitFunc) gst_element_class_init,
173 (GInstanceInitFunc) gst_element_init,
177 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
178 &element_info, G_TYPE_FLAG_ABSTRACT);
180 __gst_elementclass_factory =
181 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
182 g_once_init_leave (&gst_element_type, _type);
184 return gst_element_type;
188 gst_element_class_init (GstElementClass * klass)
190 GObjectClass *gobject_class;
192 gobject_class = (GObjectClass *) klass;
194 parent_class = g_type_class_peek_parent (klass);
197 * GstElement::pad-added:
198 * @gstelement: the object which received the signal
199 * @new_pad: the pad that has been added
201 * a new #GstPad has been added to the element. Note that this signal will
202 * usually be emitted from the context of the streaming thread. Also keep in
203 * mind that if you add new elements to the pipeline in the signal handler
204 * you will need to set them to the desired target state with
205 * gst_element_set_state() or gst_element_sync_state_with_parent().
207 gst_element_signals[PAD_ADDED] =
208 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
209 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
210 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
212 * GstElement::pad-removed:
213 * @gstelement: the object which received the signal
214 * @old_pad: the pad that has been removed
216 * a #GstPad has been removed from the element
218 gst_element_signals[PAD_REMOVED] =
219 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
220 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
221 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
223 * GstElement::no-more-pads:
224 * @gstelement: the object which received the signal
226 * This signals that the element will not generate more dynamic pads.
227 * Note that this signal will usually be emitted from the context of
228 * the streaming thread.
230 gst_element_signals[NO_MORE_PADS] =
231 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
232 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
233 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
235 gobject_class->dispose = gst_element_dispose;
236 gobject_class->finalize = gst_element_finalize;
238 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
239 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
240 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
241 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
242 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
243 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
244 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
245 klass->numpadtemplates = 0;
246 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
247 klass->set_context = GST_DEBUG_FUNCPTR (gst_element_set_context_func);
249 klass->elementfactory = NULL;
253 gst_element_base_class_init (gpointer g_class)
255 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
256 GList *node, *padtemplates;
258 /* Copy the element details here so elements can inherit the
259 * details from their base class and classes only need to set
260 * the details in class_init instead of base_init */
261 element_class->metadata =
262 element_class->metadata ? gst_structure_copy (element_class->metadata) :
263 gst_structure_new_empty ("metadata");
265 /* Copy the pad templates so elements inherit them
266 * from their base class but elements can add pad templates in class_init
267 * instead of base_init.
269 padtemplates = g_list_copy (element_class->padtemplates);
270 for (node = padtemplates; node != NULL; node = node->next) {
271 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
272 gst_object_ref (tmpl);
274 element_class->padtemplates = padtemplates;
276 /* set the factory, see gst_element_register() */
277 element_class->elementfactory =
278 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
279 __gst_elementclass_factory);
280 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
281 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
285 gst_element_base_class_finalize (gpointer g_class)
287 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
289 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
290 g_list_free (klass->padtemplates);
292 gst_structure_free (klass->metadata);
296 gst_element_init (GstElement * element)
298 GST_STATE (element) = GST_STATE_NULL;
299 GST_STATE_TARGET (element) = GST_STATE_NULL;
300 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
301 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
302 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
304 g_rec_mutex_init (&element->state_lock);
305 g_cond_init (&element->state_cond);
309 * gst_element_release_request_pad:
310 * @element: a #GstElement to release the request pad of.
311 * @pad: the #GstPad to release.
313 * Makes the element free the previously requested pad as obtained
314 * with gst_element_get_request_pad().
316 * This does not unref the pad. If the pad was created by using
317 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
318 * followed by gst_object_unref() to free the @pad.
323 gst_element_release_request_pad (GstElement * element, GstPad * pad)
325 GstElementClass *oclass;
327 g_return_if_fail (GST_IS_ELEMENT (element));
328 g_return_if_fail (GST_IS_PAD (pad));
329 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
330 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
333 oclass = GST_ELEMENT_GET_CLASS (element);
335 /* if the element implements a custom release function we call that, else we
336 * simply remove the pad from the element */
337 if (oclass->release_pad)
338 oclass->release_pad (element, pad);
340 gst_element_remove_pad (element, pad);
344 * gst_element_provide_clock:
345 * @element: a #GstElement to query
347 * Get the clock provided by the given element.
348 * <note>An element is only required to provide a clock in the PAUSED
349 * state. Some elements can provide a clock in other states.</note>
351 * Returns: (transfer full): the GstClock provided by the element or %NULL
352 * if no clock could be provided. Unref after usage.
357 gst_element_provide_clock (GstElement * element)
359 GstClock *result = NULL;
360 GstElementClass *oclass;
362 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
364 oclass = GST_ELEMENT_GET_CLASS (element);
366 if (oclass->provide_clock)
367 result = oclass->provide_clock (element);
373 gst_element_set_clock_func (GstElement * element, GstClock * clock)
377 GST_OBJECT_LOCK (element);
378 clock_p = &element->clock;
379 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
380 GST_OBJECT_UNLOCK (element);
386 * gst_element_set_clock:
387 * @element: a #GstElement to set the clock for.
388 * @clock: the #GstClock to set for the element.
390 * Sets the clock for the element. This function increases the
391 * refcount on the clock. Any previously set clock on the object
394 * Returns: %TRUE if the element accepted the clock. An element can refuse a
395 * clock when it, for example, is not able to slave its internal clock to the
396 * @clock or when it requires a specific clock to operate.
401 gst_element_set_clock (GstElement * element, GstClock * clock)
403 GstElementClass *oclass;
404 gboolean res = FALSE;
406 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
407 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
409 oclass = GST_ELEMENT_GET_CLASS (element);
411 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
413 if (oclass->set_clock)
414 res = oclass->set_clock (element, clock);
420 * gst_element_get_clock:
421 * @element: a #GstElement to get the clock of.
423 * Gets the currently configured clock of the element. This is the clock as was
424 * last set with gst_element_set_clock().
426 * Returns: (transfer full): the #GstClock of the element. unref after usage.
431 gst_element_get_clock (GstElement * element)
435 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
437 GST_OBJECT_LOCK (element);
438 if ((result = element->clock))
439 gst_object_ref (result);
440 GST_OBJECT_UNLOCK (element);
446 * gst_element_set_base_time:
447 * @element: a #GstElement.
448 * @time: the base time to set.
450 * Set the base time of an element. See gst_element_get_base_time().
455 gst_element_set_base_time (GstElement * element, GstClockTime time)
459 g_return_if_fail (GST_IS_ELEMENT (element));
461 GST_OBJECT_LOCK (element);
462 old = element->base_time;
463 element->base_time = time;
464 GST_OBJECT_UNLOCK (element);
466 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
467 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
468 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
472 * gst_element_get_base_time:
473 * @element: a #GstElement.
475 * Returns the base time of the element. The base time is the
476 * absolute time of the clock when this element was last put to
477 * PLAYING. Subtracting the base time from the clock time gives
478 * the running time of the element.
480 * Returns: the base time of the element.
485 gst_element_get_base_time (GstElement * element)
489 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
491 GST_OBJECT_LOCK (element);
492 result = element->base_time;
493 GST_OBJECT_UNLOCK (element);
499 * gst_element_set_start_time:
500 * @element: a #GstElement.
501 * @time: the base time to set.
503 * Set the start time of an element. The start time of the element is the
504 * running time of the element when it last went to the PAUSED state. In READY
505 * or after a flushing seek, it is set to 0.
507 * Toplevel elements like #GstPipeline will manage the start_time and
508 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
509 * on such a toplevel element will disable the distribution of the base_time to
510 * the children and can be useful if the application manages the base_time
511 * itself, for example if you want to synchronize capture from multiple
512 * pipelines, and you can also ensure that the pipelines have the same clock.
517 gst_element_set_start_time (GstElement * element, GstClockTime time)
521 g_return_if_fail (GST_IS_ELEMENT (element));
523 GST_OBJECT_LOCK (element);
524 old = GST_ELEMENT_START_TIME (element);
525 GST_ELEMENT_START_TIME (element) = time;
526 GST_OBJECT_UNLOCK (element);
528 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
529 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
530 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
534 * gst_element_get_start_time:
535 * @element: a #GstElement.
537 * Returns the start time of the element. The start time is the
538 * running time of the clock when this element was last put to PAUSED.
540 * Usually the start_time is managed by a toplevel element such as
545 * Returns: the start time of the element.
548 gst_element_get_start_time (GstElement * element)
552 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
554 GST_OBJECT_LOCK (element);
555 result = GST_ELEMENT_START_TIME (element);
556 GST_OBJECT_UNLOCK (element);
563 * gst_element_set_index:
564 * @element: a #GstElement.
565 * @index: (transfer none): a #GstIndex.
567 * Set @index on the element. The refcount of the index
568 * will be increased, any previously set index is unreffed.
573 gst_element_set_index (GstElement * element, GstIndex * index)
575 GstElementClass *oclass;
577 g_return_if_fail (GST_IS_ELEMENT (element));
578 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
580 oclass = GST_ELEMENT_GET_CLASS (element);
582 if (oclass->set_index)
583 oclass->set_index (element, index);
587 * gst_element_get_index:
588 * @element: a #GstElement.
590 * Gets the index from the element.
592 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
593 * element. unref after usage.
598 gst_element_get_index (GstElement * element)
600 GstElementClass *oclass;
601 GstIndex *result = NULL;
603 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
605 oclass = GST_ELEMENT_GET_CLASS (element);
607 if (oclass->get_index)
608 result = oclass->get_index (element);
615 * gst_element_add_pad:
616 * @element: a #GstElement to add the pad to.
617 * @pad: (transfer full): the #GstPad to add to the element.
619 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
620 * see gst_object_set_parent() for refcounting information.
622 * Pads are not automatically activated so elements should perform the needed
623 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
624 * state. See gst_pad_set_active() for more information about activating pads.
626 * The pad and the element should be unlocked when calling this function.
628 * This function will emit the #GstElement::pad-added signal on the element.
630 * Returns: %TRUE if the pad could be added. This function can fail when
631 * a pad with the same name already existed or the pad already had another
637 gst_element_add_pad (GstElement * element, GstPad * pad)
642 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
643 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
645 /* locking pad to look at the name */
646 GST_OBJECT_LOCK (pad);
647 pad_name = g_strdup (GST_PAD_NAME (pad));
648 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
649 GST_STR_NULL (pad_name));
650 flushing = GST_PAD_IS_FLUSHING (pad);
651 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
652 GST_OBJECT_UNLOCK (pad);
654 /* then check to see if there's already a pad by that name here */
655 GST_OBJECT_LOCK (element);
656 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
659 /* try to set the pad's parent */
660 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
661 GST_OBJECT_CAST (element))))
664 /* check for flushing pads */
665 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
666 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
667 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
668 "use gst_pad_set_active(pad,TRUE) before adding it.",
669 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
671 GST_OBJECT_LOCK (pad);
672 GST_PAD_UNSET_FLUSHING (pad);
673 GST_OBJECT_UNLOCK (pad);
678 /* add it to the list */
679 switch (gst_pad_get_direction (pad)) {
681 element->srcpads = g_list_append (element->srcpads, pad);
682 element->numsrcpads++;
685 element->sinkpads = g_list_append (element->sinkpads, pad);
686 element->numsinkpads++;
691 element->pads = g_list_append (element->pads, pad);
693 element->pads_cookie++;
694 GST_OBJECT_UNLOCK (element);
696 /* emit the PAD_ADDED signal */
697 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
704 g_critical ("Padname %s is not unique in element %s, not adding",
705 pad_name, GST_ELEMENT_NAME (element));
706 GST_OBJECT_UNLOCK (element);
713 ("Pad %s already has parent when trying to add to element %s",
714 pad_name, GST_ELEMENT_NAME (element));
715 GST_OBJECT_UNLOCK (element);
721 GST_OBJECT_LOCK (pad);
723 ("Trying to add pad %s to element %s, but it has no direction",
724 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
725 GST_OBJECT_UNLOCK (pad);
726 GST_OBJECT_UNLOCK (element);
732 * gst_element_remove_pad:
733 * @element: a #GstElement to remove pad from.
734 * @pad: (transfer full): the #GstPad to remove from the element.
736 * Removes @pad from @element. @pad will be destroyed if it has not been
737 * referenced elsewhere using gst_object_unparent().
739 * This function is used by plugin developers and should not be used
740 * by applications. Pads that were dynamically requested from elements
741 * with gst_element_get_request_pad() should be released with the
742 * gst_element_release_request_pad() function instead.
744 * Pads are not automatically deactivated so elements should perform the needed
745 * steps to deactivate the pad in case this pad is removed in the PAUSED or
746 * PLAYING state. See gst_pad_set_active() for more information about
749 * The pad and the element should be unlocked when calling this function.
751 * This function will emit the #GstElement::pad-removed signal on the element.
753 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
754 * pad does not belong to the provided element.
759 gst_element_remove_pad (GstElement * element, GstPad * pad)
763 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
764 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
766 /* locking pad to look at the name and parent */
767 GST_OBJECT_LOCK (pad);
768 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
769 GST_STR_NULL (GST_PAD_NAME (pad)));
771 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
773 GST_OBJECT_UNLOCK (pad);
776 if ((peer = gst_pad_get_peer (pad))) {
777 /* window for MT unsafeness, someone else could unlink here
778 * and then we call unlink with wrong pads. The unlink
779 * function would catch this and safely return failed. */
780 if (GST_PAD_IS_SRC (pad))
781 gst_pad_unlink (pad, peer);
783 gst_pad_unlink (peer, pad);
785 gst_object_unref (peer);
788 GST_OBJECT_LOCK (element);
789 /* remove it from the list */
790 switch (gst_pad_get_direction (pad)) {
792 element->srcpads = g_list_remove (element->srcpads, pad);
793 element->numsrcpads--;
796 element->sinkpads = g_list_remove (element->sinkpads, pad);
797 element->numsinkpads--;
800 g_critical ("Removing pad without direction???");
803 element->pads = g_list_remove (element->pads, pad);
805 element->pads_cookie++;
806 GST_OBJECT_UNLOCK (element);
808 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
809 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
811 gst_object_unparent (GST_OBJECT_CAST (pad));
818 /* locking order is element > pad */
819 GST_OBJECT_UNLOCK (pad);
821 GST_OBJECT_LOCK (element);
822 GST_OBJECT_LOCK (pad);
823 g_critical ("Padname %s:%s does not belong to element %s when removing",
824 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
825 GST_OBJECT_UNLOCK (pad);
826 GST_OBJECT_UNLOCK (element);
832 * gst_element_no_more_pads:
833 * @element: a #GstElement
835 * Use this function to signal that the element does not expect any more pads
836 * to show up in the current pipeline. This function should be called whenever
837 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
838 * pad templates use this in combination with autopluggers to figure out that
839 * the element is done initializing its pads.
841 * This function emits the #GstElement::no-more-pads signal.
846 gst_element_no_more_pads (GstElement * element)
848 g_return_if_fail (GST_IS_ELEMENT (element));
850 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
854 pad_compare_name (GstPad * pad1, const gchar * name)
858 GST_OBJECT_LOCK (pad1);
859 result = strcmp (GST_PAD_NAME (pad1), name);
860 GST_OBJECT_UNLOCK (pad1);
866 * gst_element_get_static_pad:
867 * @element: a #GstElement to find a static pad of.
868 * @name: the name of the static #GstPad to retrieve.
870 * Retrieves a pad from @element by name. This version only retrieves
871 * already-existing (i.e. 'static') pads.
873 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
879 gst_element_get_static_pad (GstElement * element, const gchar * name)
882 GstPad *result = NULL;
884 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
885 g_return_val_if_fail (name != NULL, NULL);
887 GST_OBJECT_LOCK (element);
889 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
891 result = GST_PAD_CAST (find->data);
892 gst_object_ref (result);
895 if (result == NULL) {
896 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
897 name, GST_ELEMENT_NAME (element));
899 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
900 GST_ELEMENT_NAME (element), name);
902 GST_OBJECT_UNLOCK (element);
908 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
909 const gchar * name, const GstCaps * caps)
911 GstPad *newpad = NULL;
912 GstElementClass *oclass;
914 oclass = GST_ELEMENT_GET_CLASS (element);
916 #ifndef G_DISABLE_CHECKS
917 /* Some sanity checking here */
921 /* Is this the template name? */
922 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
923 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
925 const gchar *str, *data;
928 /* Otherwise check if it's a valid name for the name template */
929 str = strchr (templ->name_template, '%');
930 g_return_val_if_fail (str != NULL, NULL);
931 g_return_val_if_fail (strncmp (templ->name_template, name,
932 str - templ->name_template) == 0, NULL);
933 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
935 data = name + (str - templ->name_template);
937 /* Can either be %s or %d or %u, do sanity checking for %d */
938 if (*(str + 1) == 'd') {
942 tmp = g_ascii_strtoll (data, &endptr, 10);
943 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
944 && *endptr == '\0', NULL);
945 } else if (*(str + 1) == 'u') {
949 tmp = g_ascii_strtoull (data, &endptr, 10);
950 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
954 pad = gst_element_get_static_pad (element, name);
956 gst_object_unref (pad);
957 /* FIXME 0.11: Change this to g_return_val_if_fail() */
958 g_critical ("Element %s already has a pad named %s, the behaviour of "
959 " gst_element_get_request_pad() for existing pads is undefined!",
960 GST_ELEMENT_NAME (element), name);
965 if (oclass->request_new_pad)
966 newpad = (oclass->request_new_pad) (element, templ, name, caps);
969 gst_object_ref (newpad);
975 * gst_element_get_request_pad:
976 * @element: a #GstElement to find a request pad of.
977 * @name: the name of the request #GstPad to retrieve.
979 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
980 * retrieves request pads. The pad should be released with
981 * gst_element_release_request_pad().
983 * This method is slow and will be deprecated in the future. New code should
984 * use gst_element_request_pad() with the requested template.
986 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
987 * Release after usage.
990 gst_element_get_request_pad (GstElement * element, const gchar * name)
992 GstPadTemplate *templ = NULL;
994 const gchar *req_name = NULL;
995 gboolean templ_found = FALSE;
998 gchar *str, *endptr = NULL;
999 GstElementClass *class;
1001 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1002 g_return_val_if_fail (name != NULL, NULL);
1004 class = GST_ELEMENT_GET_CLASS (element);
1006 /* if the name contains a %, we assume it's the complete template name. Get
1007 * the template and try to get a pad */
1008 if (strstr (name, "%")) {
1009 templ = gst_element_class_get_request_pad_template (class, name);
1014 /* there is no % in the name, try to find a matching template */
1015 list = class->padtemplates;
1016 while (!templ_found && list) {
1017 templ = (GstPadTemplate *) list->data;
1018 if (templ->presence == GST_PAD_REQUEST) {
1019 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1020 templ->name_template);
1021 /* see if we find an exact match */
1022 if (strcmp (name, templ->name_template) == 0) {
1027 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1028 and %d and %u, occurring at the end of the name_template, are the only
1030 else if ((str = strchr (templ->name_template, '%'))
1031 && strncmp (templ->name_template, name,
1032 str - templ->name_template) == 0
1033 && strlen (name) > str - templ->name_template) {
1034 data = name + (str - templ->name_template);
1035 if (*(str + 1) == 'd') {
1039 tmp = strtol (data, &endptr, 10);
1040 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1046 } else if (*(str + 1) == 'u') {
1050 tmp = strtoul (data, &endptr, 10);
1051 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1071 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1077 * gst_element_request_pad:
1078 * @element: a #GstElement to find a request pad of.
1079 * @templ: a #GstPadTemplate of which we want a pad of.
1080 * @name: (transfer none) (allow-none): the name of the request #GstPad
1081 * to retrieve. Can be %NULL.
1082 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1083 * request. Can be %NULL.
1085 * Retrieves a request pad from the element according to the provided template.
1086 * Pad templates can be looked up using
1087 * gst_element_factory_get_static_pad_templates().
1089 * The pad should be released with gst_element_release_request_pad().
1091 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1092 * Release after usage.
1095 gst_element_request_pad (GstElement * element,
1096 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1098 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1099 g_return_val_if_fail (templ != NULL, NULL);
1100 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1102 return _gst_element_request_pad (element, templ, name, caps);
1105 static GstIterator *
1106 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1108 GstIterator *result;
1110 GST_OBJECT_LOCK (element);
1111 result = gst_iterator_new_list (GST_TYPE_PAD,
1112 GST_OBJECT_GET_LOCK (element),
1113 &element->pads_cookie, padlist, (GObject *) element, NULL);
1114 GST_OBJECT_UNLOCK (element);
1120 * gst_element_iterate_pads:
1121 * @element: a #GstElement to iterate pads of.
1123 * Retrieves an iterator of @element's pads. The iterator should
1124 * be freed after usage. Also more specialized iterators exists such as
1125 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1127 * The order of pads returned by the iterator will be the order in which
1128 * the pads were added to the element.
1130 * Returns: (transfer full): the #GstIterator of #GstPad.
1135 gst_element_iterate_pads (GstElement * element)
1137 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1139 return gst_element_iterate_pad_list (element, &element->pads);
1143 * gst_element_iterate_src_pads:
1144 * @element: a #GstElement.
1146 * Retrieves an iterator of @element's source pads.
1148 * The order of pads returned by the iterator will be the order in which
1149 * the pads were added to the element.
1151 * Returns: (transfer full): the #GstIterator of #GstPad.
1156 gst_element_iterate_src_pads (GstElement * element)
1158 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1160 return gst_element_iterate_pad_list (element, &element->srcpads);
1164 * gst_element_iterate_sink_pads:
1165 * @element: a #GstElement.
1167 * Retrieves an iterator of @element's sink pads.
1169 * The order of pads returned by the iterator will be the order in which
1170 * the pads were added to the element.
1172 * Returns: (transfer full): the #GstIterator of #GstPad.
1177 gst_element_iterate_sink_pads (GstElement * element)
1179 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1181 return gst_element_iterate_pad_list (element, &element->sinkpads);
1185 * gst_element_class_add_pad_template:
1186 * @klass: the #GstElementClass to add the pad template to.
1187 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1189 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1190 * functions of classes. If a pad template with the same name as an already
1191 * existing one is added the old one is replaced by the new one.
1195 gst_element_class_add_pad_template (GstElementClass * klass,
1196 GstPadTemplate * templ)
1198 GList *template_list = klass->padtemplates;
1200 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1201 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1203 /* If we already have a pad template with the same name replace the
1205 while (template_list) {
1206 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1208 /* Found pad with the same name, replace and return */
1209 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1210 gst_object_unref (padtempl);
1211 template_list->data = templ;
1214 template_list = g_list_next (template_list);
1217 /* Take ownership of the floating ref */
1218 gst_object_ref_sink (templ);
1220 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1221 klass->numpadtemplates++;
1225 * gst_element_class_add_metadata:
1226 * @klass: class to set metadata for
1227 * @key: the key to set
1228 * @value: the value to set
1230 * Set @key with @value as metadata in @klass.
1233 gst_element_class_add_metadata (GstElementClass * klass,
1234 const gchar * key, const gchar * value)
1236 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1237 g_return_if_fail (key != NULL);
1238 g_return_if_fail (value != NULL);
1240 gst_structure_set ((GstStructure *) klass->metadata,
1241 key, G_TYPE_STRING, value, NULL);
1245 * gst_element_class_add_static_metadata:
1246 * @klass: class to set metadata for
1247 * @key: the key to set
1248 * @value: the value to set
1250 * Set @key with @value as metadata in @klass.
1252 * Same as gst_element_class_add_metadata(), but @value must be a static string
1253 * or an inlined string, as it will not be copied. (GStreamer plugins will
1254 * be made resident once loaded, so this function can be used even from
1255 * dynamically loaded plugins.)
1258 gst_element_class_add_static_metadata (GstElementClass * klass,
1259 const gchar * key, const gchar * value)
1261 GValue val = G_VALUE_INIT;
1263 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1264 g_return_if_fail (key != NULL);
1265 g_return_if_fail (value != NULL);
1267 g_value_init (&val, G_TYPE_STRING);
1268 g_value_set_static_string (&val, value);
1269 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1273 * gst_element_class_set_metadata:
1274 * @klass: class to set metadata for
1275 * @longname: The long English name of the element. E.g. "File Sink"
1276 * @classification: String describing the type of element, as an unordered list
1277 * separated with slashes ('/'). See draft-klass.txt of the design docs
1278 * for more details and common types. E.g: "Sink/File"
1279 * @description: Sentence describing the purpose of the element.
1280 * E.g: "Write stream to a file"
1281 * @author: Name and contact details of the author(s). Use \n to separate
1282 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1284 * Sets the detailed information for a #GstElementClass.
1285 * <note>This function is for use in _class_init functions only.</note>
1288 gst_element_class_set_metadata (GstElementClass * klass,
1289 const gchar * longname, const gchar * classification,
1290 const gchar * description, const gchar * author)
1292 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1293 g_return_if_fail (longname != NULL && *longname != '\0');
1294 g_return_if_fail (classification != NULL && *classification != '\0');
1295 g_return_if_fail (description != NULL && *description != '\0');
1296 g_return_if_fail (author != NULL && *author != '\0');
1298 gst_structure_id_set ((GstStructure *) klass->metadata,
1299 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1300 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1301 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1302 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1306 * gst_element_class_set_static_metadata:
1307 * @klass: class to set metadata for
1308 * @longname: The long English name of the element. E.g. "File Sink"
1309 * @classification: String describing the type of element, as an unordered list
1310 * separated with slashes ('/'). See draft-klass.txt of the design docs
1311 * for more details and common types. E.g: "Sink/File"
1312 * @description: Sentence describing the purpose of the element.
1313 * E.g: "Write stream to a file"
1314 * @author: Name and contact details of the author(s). Use \n to separate
1315 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1317 * Sets the detailed information for a #GstElementClass.
1318 * <note>This function is for use in _class_init functions only.</note>
1320 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1321 * @description, and @author must be static strings or inlined strings, as
1322 * they will not be copied. (GStreamer plugins will be made resident once
1323 * loaded, so this function can be used even from dynamically loaded plugins.)
1326 gst_element_class_set_static_metadata (GstElementClass * klass,
1327 const gchar * longname, const gchar * classification,
1328 const gchar * description, const gchar * author)
1330 GstStructure *s = (GstStructure *) klass->metadata;
1331 GValue val = G_VALUE_INIT;
1333 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1334 g_return_if_fail (longname != NULL && *longname != '\0');
1335 g_return_if_fail (classification != NULL && *classification != '\0');
1336 g_return_if_fail (description != NULL && *description != '\0');
1337 g_return_if_fail (author != NULL && *author != '\0');
1339 g_value_init (&val, G_TYPE_STRING);
1341 g_value_set_static_string (&val, longname);
1342 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1344 g_value_set_static_string (&val, classification);
1345 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1347 g_value_set_static_string (&val, description);
1348 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1351 g_value_set_static_string (&val, author);
1352 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1356 * gst_element_class_get_metadata:
1357 * @klass: class to get metadata for
1358 * @key: the key to get
1360 * Get metadata with @key in @klass.
1362 * Returns: the metadata for @key.
1365 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1367 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1368 g_return_val_if_fail (key != NULL, NULL);
1370 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1374 * gst_element_class_get_pad_template_list:
1375 * @element_class: a #GstElementClass to get pad templates of.
1377 * Retrieves a list of the pad templates associated with @element_class. The
1378 * list must not be modified by the calling code.
1379 * <note>If you use this function in the #GInstanceInitFunc of an object class
1380 * that has subclasses, make sure to pass the g_class parameter of the
1381 * #GInstanceInitFunc here.</note>
1383 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1387 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1389 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1391 return element_class->padtemplates;
1395 * gst_element_class_get_pad_template:
1396 * @element_class: a #GstElementClass to get the pad template of.
1397 * @name: the name of the #GstPadTemplate to get.
1399 * Retrieves a padtemplate from @element_class with the given name.
1400 * <note>If you use this function in the #GInstanceInitFunc of an object class
1401 * that has subclasses, make sure to pass the g_class parameter of the
1402 * #GInstanceInitFunc here.</note>
1404 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1405 * if none was found. No unreferencing is necessary.
1408 gst_element_class_get_pad_template (GstElementClass *
1409 element_class, const gchar * name)
1413 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1414 g_return_val_if_fail (name != NULL, NULL);
1416 padlist = element_class->padtemplates;
1419 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1421 if (strcmp (padtempl->name_template, name) == 0)
1424 padlist = g_list_next (padlist);
1430 static GstPadTemplate *
1431 gst_element_class_get_request_pad_template (GstElementClass *
1432 element_class, const gchar * name)
1434 GstPadTemplate *tmpl;
1436 tmpl = gst_element_class_get_pad_template (element_class, name);
1437 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1443 /* get a random pad on element of the given direction.
1444 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1447 gst_element_get_random_pad (GstElement * element,
1448 gboolean need_linked, GstPadDirection dir)
1450 GstPad *result = NULL;
1453 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1457 GST_OBJECT_LOCK (element);
1458 pads = element->srcpads;
1461 GST_OBJECT_LOCK (element);
1462 pads = element->sinkpads;
1465 goto wrong_direction;
1467 for (; pads; pads = g_list_next (pads)) {
1468 GstPad *pad = GST_PAD_CAST (pads->data);
1470 GST_OBJECT_LOCK (pad);
1471 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1472 GST_DEBUG_PAD_NAME (pad));
1474 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1475 /* if we require a linked pad, and it is not linked, continue the
1477 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1478 GST_DEBUG_PAD_NAME (pad));
1479 GST_OBJECT_UNLOCK (pad);
1482 /* found a pad, stop search */
1483 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1484 GST_DEBUG_PAD_NAME (pad));
1485 GST_OBJECT_UNLOCK (pad);
1491 gst_object_ref (result);
1493 GST_OBJECT_UNLOCK (element);
1497 /* ERROR handling */
1500 g_warning ("unknown pad direction %d", dir);
1506 gst_element_default_send_event (GstElement * element, GstEvent * event)
1508 gboolean result = FALSE;
1511 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1512 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1513 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1516 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1517 "pushing %s event to random %s pad %s:%s",
1518 GST_EVENT_TYPE_NAME (event),
1519 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1520 GST_DEBUG_PAD_NAME (pad));
1522 result = gst_pad_push_event (pad, event);
1523 gst_object_unref (pad);
1525 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1526 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1527 gst_event_unref (event);
1533 * gst_element_send_event:
1534 * @element: a #GstElement to send the event to.
1535 * @event: (transfer full): the #GstEvent to send to the element.
1537 * Sends an event to an element. If the element doesn't implement an
1538 * event handler, the event will be pushed on a random linked sink pad for
1539 * upstream events or a random linked source pad for downstream events.
1541 * This function takes owership of the provided event so you should
1542 * gst_event_ref() it if you want to reuse the event after this call.
1546 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1547 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1550 gst_element_send_event (GstElement * element, GstEvent * event)
1552 GstElementClass *oclass;
1553 gboolean result = FALSE;
1555 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1556 g_return_val_if_fail (event != NULL, FALSE);
1558 oclass = GST_ELEMENT_GET_CLASS (element);
1560 GST_STATE_LOCK (element);
1561 if (oclass->send_event) {
1562 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1563 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1564 result = oclass->send_event (element, event);
1566 GST_STATE_UNLOCK (element);
1573 * @element: a #GstElement to send the event to.
1574 * @rate: The new playback rate
1575 * @format: The format of the seek values
1576 * @flags: The optional seek flags.
1577 * @start_type: The type and flags for the new start position
1578 * @start: The value of the new start position
1579 * @stop_type: The type and flags for the new stop position
1580 * @stop: The value of the new stop position
1582 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1583 * the parameters. The seek event is sent to the element using
1584 * gst_element_send_event().
1588 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1589 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1592 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1593 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1594 GstSeekType stop_type, gint64 stop)
1599 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1602 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1604 result = gst_element_send_event (element, event);
1610 gst_element_default_query (GstElement * element, GstQuery * query)
1612 gboolean result = FALSE;
1615 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1617 result = gst_pad_query (pad, query);
1619 gst_object_unref (pad);
1621 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1623 GstPad *peer = gst_pad_get_peer (pad);
1626 result = gst_pad_query (peer, query);
1628 gst_object_unref (peer);
1630 gst_object_unref (pad);
1637 * gst_element_query:
1638 * @element: a #GstElement to perform the query on.
1639 * @query: (transfer none): the #GstQuery.
1641 * Performs a query on the given element.
1643 * For elements that don't implement a query handler, this function
1644 * forwards the query to a random srcpad or to the peer of a
1645 * random linked sinkpad of this element.
1647 * Please note that some queries might need a running pipeline to work.
1649 * Returns: TRUE if the query could be performed.
1654 gst_element_query (GstElement * element, GstQuery * query)
1656 GstElementClass *klass;
1658 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1659 g_return_val_if_fail (query != NULL, FALSE);
1661 klass = GST_ELEMENT_GET_CLASS (element);
1663 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1664 GST_ELEMENT_NAME (element));
1665 return klass->query (element, query);
1672 gst_element_post_message_default (GstElement * element, GstMessage * message)
1675 gboolean result = FALSE;
1677 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1678 g_return_val_if_fail (message != NULL, FALSE);
1680 GST_OBJECT_LOCK (element);
1683 if (G_UNLIKELY (bus == NULL))
1686 gst_object_ref (bus);
1687 GST_OBJECT_UNLOCK (element);
1689 /* we release the element lock when posting the message so that any
1690 * (synchronous) message handlers can operate on the element */
1691 result = gst_bus_post (bus, message);
1692 gst_object_unref (bus);
1699 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1700 "not posting message %p: no bus", message);
1701 GST_OBJECT_UNLOCK (element);
1702 gst_message_unref (message);
1708 * gst_element_post_message:
1709 * @element: a #GstElement posting the message
1710 * @message: (transfer full): a #GstMessage to post
1712 * Post a message on the element's #GstBus. This function takes ownership of the
1713 * message; if you want to access the message after this call, you should add an
1714 * additional reference before calling.
1716 * Returns: %TRUE if the message was successfully posted. The function returns
1717 * %FALSE if the element did not have a bus.
1722 gst_element_post_message (GstElement * element, GstMessage * message)
1724 GstElementClass *klass;
1726 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1727 g_return_val_if_fail (message != NULL, FALSE);
1729 klass = GST_ELEMENT_GET_CLASS (element);
1730 if (klass->post_message)
1731 return klass->post_message (element, message);
1737 * _gst_element_error_printf:
1738 * @format: the printf-like format to use, or %NULL
1740 * This function is only used internally by the gst_element_error() macro.
1742 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1748 _gst_element_error_printf (const gchar * format, ...)
1759 va_start (args, format);
1761 len = __gst_vasprintf (&buffer, format, args);
1772 * gst_element_message_full:
1773 * @element: a #GstElement to send message from
1774 * @type: the #GstMessageType
1775 * @domain: the GStreamer GError domain this message belongs to
1776 * @code: the GError code belonging to the domain
1777 * @text: (allow-none) (transfer full): an allocated text string to be used
1778 * as a replacement for the default message connected to code,
1780 * @debug: (allow-none) (transfer full): an allocated debug message to be
1781 * used as a replacement for the default debugging information,
1783 * @file: the source code file where the error was generated
1784 * @function: the source code function where the error was generated
1785 * @line: the source code line where the error was generated
1787 * Post an error, warning or info message on the bus from inside an element.
1789 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1790 * #GST_MESSAGE_INFO.
1794 void gst_element_message_full
1795 (GstElement * element, GstMessageType type,
1796 GQuark domain, gint code, gchar * text,
1797 gchar * debug, const gchar * file, const gchar * function, gint line)
1799 GError *gerror = NULL;
1803 gboolean has_debug = TRUE;
1804 GstMessage *message = NULL;
1807 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1808 g_return_if_fail (GST_IS_ELEMENT (element));
1809 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1810 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1812 /* check if we send the given text or the default error text */
1813 if ((text == NULL) || (text[0] == 0)) {
1814 /* text could have come from g_strdup_printf (""); */
1816 sent_text = gst_error_get_message (domain, code);
1820 /* construct a sent_debug with extra information from source */
1821 if ((debug == NULL) || (debug[0] == 0)) {
1822 /* debug could have come from g_strdup_printf (""); */
1826 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1828 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1829 file, line, function, name, debug);
1831 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1832 file, line, function, name);
1836 /* create gerror and post message */
1837 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1839 gerror = g_error_new_literal (domain, code, sent_text);
1842 case GST_MESSAGE_ERROR:
1844 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1846 case GST_MESSAGE_WARNING:
1847 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1850 case GST_MESSAGE_INFO:
1851 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1855 g_assert_not_reached ();
1858 gst_element_post_message (element, message);
1860 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1861 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1864 g_error_free (gerror);
1865 g_free (sent_debug);
1870 * gst_element_is_locked_state:
1871 * @element: a #GstElement.
1873 * Checks if the state of an element is locked.
1874 * If the state of an element is locked, state changes of the parent don't
1875 * affect the element.
1876 * This way you can leave currently unused elements inside bins. Just lock their
1877 * state before changing the state from #GST_STATE_NULL.
1881 * Returns: TRUE, if the element's state is locked.
1884 gst_element_is_locked_state (GstElement * element)
1888 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1890 GST_OBJECT_LOCK (element);
1891 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1892 GST_OBJECT_UNLOCK (element);
1898 * gst_element_set_locked_state:
1899 * @element: a #GstElement
1900 * @locked_state: TRUE to lock the element's state
1902 * Locks the state of an element, so state changes of the parent don't affect
1903 * this element anymore.
1907 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1908 * or the elements state-locking needed no change.
1911 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1915 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1917 GST_OBJECT_LOCK (element);
1918 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1920 if (G_UNLIKELY (old == locked_state))
1924 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1925 GST_ELEMENT_NAME (element));
1926 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1928 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1929 GST_ELEMENT_NAME (element));
1930 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1932 GST_OBJECT_UNLOCK (element);
1938 GST_CAT_DEBUG (GST_CAT_STATES,
1939 "elements %s was already in locked state %d",
1940 GST_ELEMENT_NAME (element), old);
1941 GST_OBJECT_UNLOCK (element);
1948 * gst_element_sync_state_with_parent:
1949 * @element: a #GstElement.
1951 * Tries to change the state of the element to the same as its parent.
1952 * If this function returns FALSE, the state of element is undefined.
1954 * Returns: TRUE, if the element's state could be synced to the parent's state.
1959 gst_element_sync_state_with_parent (GstElement * element)
1963 GstStateChangeReturn ret;
1965 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1967 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1968 GstState parent_current, parent_pending;
1970 GST_OBJECT_LOCK (parent);
1971 parent_current = GST_STATE (parent);
1972 parent_pending = GST_STATE_PENDING (parent);
1973 GST_OBJECT_UNLOCK (parent);
1975 /* set to pending if there is one, else we set it to the current state of
1977 if (parent_pending != GST_STATE_VOID_PENDING)
1978 target = parent_pending;
1980 target = parent_current;
1982 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1983 "syncing state (%s) to parent %s %s (%s, %s)",
1984 gst_element_state_get_name (GST_STATE (element)),
1985 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1986 gst_element_state_get_name (parent_current),
1987 gst_element_state_get_name (parent_pending));
1989 ret = gst_element_set_state (element, target);
1990 if (ret == GST_STATE_CHANGE_FAILURE)
1993 gst_object_unref (parent);
1997 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
2004 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2005 "syncing state failed (%s)",
2006 gst_element_state_change_return_get_name (ret));
2007 gst_object_unref (parent);
2013 static GstStateChangeReturn
2014 gst_element_get_state_func (GstElement * element,
2015 GstState * state, GstState * pending, GstClockTime timeout)
2017 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2018 GstState old_pending;
2020 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2021 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2023 GST_OBJECT_LOCK (element);
2024 ret = GST_STATE_RETURN (element);
2025 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2026 gst_element_state_change_return_get_name (ret));
2028 /* we got an error, report immediately */
2029 if (ret == GST_STATE_CHANGE_FAILURE)
2032 /* we got no_preroll, report immediately */
2033 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2036 /* no need to wait async if we are not async */
2037 if (ret != GST_STATE_CHANGE_ASYNC)
2040 old_pending = GST_STATE_PENDING (element);
2041 if (old_pending != GST_STATE_VOID_PENDING) {
2045 /* get cookie to detect state changes during waiting */
2046 cookie = element->state_cookie;
2048 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2049 "waiting for element to commit state");
2051 /* we have a pending state change, wait for it to complete */
2052 if (timeout != GST_CLOCK_TIME_NONE) {
2054 /* make timeout absolute */
2055 end_time = g_get_monotonic_time () + (timeout / 1000);
2056 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2058 GST_STATE_WAIT (element);
2063 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2064 /* timeout triggered */
2065 ret = GST_STATE_CHANGE_ASYNC;
2067 if (cookie != element->state_cookie)
2070 /* could be success or failure */
2071 if (old_pending == GST_STATE (element)) {
2072 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2073 ret = GST_STATE_CHANGE_SUCCESS;
2075 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2076 ret = GST_STATE_CHANGE_FAILURE;
2079 /* if nothing is pending anymore we can return SUCCESS */
2080 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2081 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2082 ret = GST_STATE_CHANGE_SUCCESS;
2088 *state = GST_STATE (element);
2090 *pending = GST_STATE_PENDING (element);
2092 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2093 "state current: %s, pending: %s, result: %s",
2094 gst_element_state_get_name (GST_STATE (element)),
2095 gst_element_state_get_name (GST_STATE_PENDING (element)),
2096 gst_element_state_change_return_get_name (ret));
2097 GST_OBJECT_UNLOCK (element);
2104 *state = GST_STATE_VOID_PENDING;
2106 *pending = GST_STATE_VOID_PENDING;
2108 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2110 GST_OBJECT_UNLOCK (element);
2112 return GST_STATE_CHANGE_FAILURE;
2117 * gst_element_get_state:
2118 * @element: a #GstElement to get the state of.
2119 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2121 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2122 * state. Can be %NULL.
2123 * @timeout: a #GstClockTime to specify the timeout for an async
2124 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2126 * Gets the state of the element.
2128 * For elements that performed an ASYNC state change, as reported by
2129 * gst_element_set_state(), this function will block up to the
2130 * specified timeout value for the state change to complete.
2131 * If the element completes the state change or goes into
2132 * an error, this function returns immediately with a return value of
2133 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2135 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2136 * returns the current and pending state immediately.
2138 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2139 * successfully changed its state but is not able to provide data yet.
2140 * This mostly happens for live sources that only produce data in
2141 * %GST_STATE_PLAYING. While the state change return is equivalent to
2142 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2143 * some sink elements might not be able to complete their state change because
2144 * an element is not producing data to complete the preroll. When setting the
2145 * element to playing, the preroll will complete and playback will start.
2147 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2148 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2149 * element is still performing a state change or
2150 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2154 GstStateChangeReturn
2155 gst_element_get_state (GstElement * element,
2156 GstState * state, GstState * pending, GstClockTime timeout)
2158 GstElementClass *oclass;
2159 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2161 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2163 oclass = GST_ELEMENT_GET_CLASS (element);
2165 if (oclass->get_state)
2166 result = (oclass->get_state) (element, state, pending, timeout);
2172 * gst_element_abort_state:
2173 * @element: a #GstElement to abort the state of.
2175 * Abort the state change of the element. This function is used
2176 * by elements that do asynchronous state changes and find out
2177 * something is wrong.
2179 * This function should be called with the STATE_LOCK held.
2184 gst_element_abort_state (GstElement * element)
2188 #ifndef GST_DISABLE_GST_DEBUG
2192 g_return_if_fail (GST_IS_ELEMENT (element));
2194 GST_OBJECT_LOCK (element);
2195 pending = GST_STATE_PENDING (element);
2197 if (pending == GST_STATE_VOID_PENDING ||
2198 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2199 goto nothing_aborted;
2201 #ifndef GST_DISABLE_GST_DEBUG
2202 old_state = GST_STATE (element);
2204 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2205 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2206 gst_element_state_get_name (pending));
2210 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2212 GST_STATE_BROADCAST (element);
2213 GST_OBJECT_UNLOCK (element);
2219 GST_OBJECT_UNLOCK (element);
2224 /* Not static because GstBin has manual state handling too */
2226 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2227 GstState newstate, GstState pending)
2229 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2230 GstMessage *message;
2232 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2233 "notifying about state-changed %s to %s (%s pending)",
2234 gst_element_state_get_name (oldstate),
2235 gst_element_state_get_name (newstate),
2236 gst_element_state_get_name (pending));
2238 if (klass->state_changed)
2239 klass->state_changed (element, oldstate, newstate, pending);
2241 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2242 oldstate, newstate, pending);
2243 gst_element_post_message (element, message);
2247 * gst_element_continue_state:
2248 * @element: a #GstElement to continue the state change of.
2249 * @ret: The previous state return value
2251 * Commit the state change of the element and proceed to the next
2252 * pending state if any. This function is used
2253 * by elements that do asynchronous state changes.
2254 * The core will normally call this method automatically when an
2255 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2257 * If after calling this method the element still has not reached
2258 * the pending state, the next state change is performed.
2260 * This method is used internally and should normally not be called by plugins
2263 * Returns: The result of the commit state change.
2267 GstStateChangeReturn
2268 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2270 GstStateChangeReturn old_ret;
2271 GstState old_state, old_next;
2272 GstState current, next, pending;
2273 GstStateChange transition;
2275 GST_OBJECT_LOCK (element);
2276 old_ret = GST_STATE_RETURN (element);
2277 GST_STATE_RETURN (element) = ret;
2278 pending = GST_STATE_PENDING (element);
2280 /* check if there is something to commit */
2281 if (pending == GST_STATE_VOID_PENDING)
2282 goto nothing_pending;
2284 old_state = GST_STATE (element);
2285 /* this is the state we should go to next */
2286 old_next = GST_STATE_NEXT (element);
2287 /* update current state */
2288 current = GST_STATE (element) = old_next;
2290 /* see if we reached the final state */
2291 if (pending == current)
2294 next = GST_STATE_GET_NEXT (current, pending);
2295 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2297 GST_STATE_NEXT (element) = next;
2299 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2300 GST_OBJECT_UNLOCK (element);
2302 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2303 "committing state from %s to %s, pending %s, next %s",
2304 gst_element_state_get_name (old_state),
2305 gst_element_state_get_name (old_next),
2306 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2308 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2310 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2311 "continue state change %s to %s, final %s",
2312 gst_element_state_get_name (current),
2313 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2315 ret = gst_element_change_state (element, transition);
2321 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2322 GST_OBJECT_UNLOCK (element);
2327 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2328 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2330 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2331 "completed state change to %s", gst_element_state_get_name (pending));
2332 GST_OBJECT_UNLOCK (element);
2334 /* don't post silly messages with the same state. This can happen
2335 * when an element state is changed to what it already was. For bins
2336 * this can be the result of a lost state, which we check with the
2337 * previous return value.
2338 * We do signal the cond though as a _get_state() might be blocking
2340 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2341 _priv_gst_element_state_changed (element, old_state, old_next,
2342 GST_STATE_VOID_PENDING);
2344 GST_STATE_BROADCAST (element);
2351 * gst_element_lost_state:
2352 * @element: a #GstElement the state is lost of
2354 * Brings the element to the lost state. The current state of the
2355 * element is copied to the pending state so that any call to
2356 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2358 * An ASYNC_START message is posted. If the element was PLAYING, it will
2359 * go to PAUSED. The element will be restored to its PLAYING state by
2360 * the parent pipeline when it prerolls again.
2362 * This is mostly used for elements that lost their preroll buffer
2363 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2364 * they will go to their pending state again when a new preroll buffer is
2365 * queued. This function can only be called when the element is currently
2366 * not in error or an async state change.
2368 * This function is used internally and should normally not be called from
2369 * plugins or applications.
2372 gst_element_lost_state (GstElement * element)
2374 GstState old_state, new_state;
2375 GstMessage *message;
2377 g_return_if_fail (GST_IS_ELEMENT (element));
2379 GST_OBJECT_LOCK (element);
2380 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2383 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2384 goto only_async_start;
2386 old_state = GST_STATE (element);
2388 /* when we were PLAYING, the new state is PAUSED. We will also not
2389 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2390 * when we preroll. */
2391 if (old_state > GST_STATE_PAUSED)
2392 new_state = GST_STATE_PAUSED;
2394 new_state = old_state;
2396 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2397 "lost state of %s to %s", gst_element_state_get_name (old_state),
2398 gst_element_state_get_name (new_state));
2400 GST_STATE (element) = new_state;
2401 GST_STATE_NEXT (element) = new_state;
2402 GST_STATE_PENDING (element) = new_state;
2403 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2404 GST_OBJECT_UNLOCK (element);
2406 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2408 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2409 gst_element_post_message (element, message);
2415 GST_OBJECT_UNLOCK (element);
2420 GST_OBJECT_UNLOCK (element);
2422 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2423 gst_element_post_message (element, message);
2429 * gst_element_set_state:
2430 * @element: a #GstElement to change state of.
2431 * @state: the element's new #GstState.
2433 * Sets the state of the element. This function will try to set the
2434 * requested state by going through all the intermediary states and calling
2435 * the class's state change function for each.
2437 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2438 * element will perform the remainder of the state change asynchronously in
2440 * An application can use gst_element_get_state() to wait for the completion
2441 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2442 * %GST_MESSAGE_STATE_CHANGED on the bus.
2444 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2445 * #GST_STATE_CHANGE_ASYNC.
2447 * Returns: Result of the state change using #GstStateChangeReturn.
2451 GstStateChangeReturn
2452 gst_element_set_state (GstElement * element, GstState state)
2454 GstElementClass *oclass;
2455 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2457 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2459 oclass = GST_ELEMENT_GET_CLASS (element);
2461 if (oclass->set_state)
2462 result = (oclass->set_state) (element, state);
2468 * default set state function, calculates the next state based
2469 * on current state and calls the change_state function
2471 static GstStateChangeReturn
2472 gst_element_set_state_func (GstElement * element, GstState state)
2474 GstState current, next, old_pending;
2475 GstStateChangeReturn ret;
2476 GstStateChange transition;
2477 GstStateChangeReturn old_ret;
2479 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2481 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2482 gst_element_state_get_name (state));
2484 /* state lock is taken to protect the set_state() and get_state()
2485 * procedures, it does not lock any variables. */
2486 GST_STATE_LOCK (element);
2488 /* now calculate how to get to the new state */
2489 GST_OBJECT_LOCK (element);
2490 old_ret = GST_STATE_RETURN (element);
2491 /* previous state change returned an error, remove all pending
2492 * and next states */
2493 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2494 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2495 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2496 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2499 current = GST_STATE (element);
2500 next = GST_STATE_NEXT (element);
2501 old_pending = GST_STATE_PENDING (element);
2503 /* this is the (new) state we should go to. TARGET is the last state we set on
2505 if (state != GST_STATE_TARGET (element)) {
2506 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2507 "setting target state to %s", gst_element_state_get_name (state));
2508 GST_STATE_TARGET (element) = state;
2509 /* increment state cookie so that we can track each state change. We only do
2510 * this if this is actually a new state change. */
2511 element->state_cookie++;
2513 GST_STATE_PENDING (element) = state;
2515 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2516 "current %s, old_pending %s, next %s, old return %s",
2517 gst_element_state_get_name (current),
2518 gst_element_state_get_name (old_pending),
2519 gst_element_state_get_name (next),
2520 gst_element_state_change_return_get_name (old_ret));
2522 /* if the element was busy doing a state change, we just update the
2523 * target state, it'll get to it async then. */
2524 if (old_pending != GST_STATE_VOID_PENDING) {
2525 /* upwards state change will happen ASYNC */
2526 if (old_pending <= state)
2528 /* element is going to this state already */
2529 else if (next == state)
2531 /* element was performing an ASYNC upward state change and
2532 * we request to go downward again. Start from the next pending
2534 else if (next > state
2535 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2539 next = GST_STATE_GET_NEXT (current, state);
2540 /* now we store the next state */
2541 GST_STATE_NEXT (element) = next;
2542 /* mark busy, we need to check that there is actually a state change
2543 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2544 * the default element change_state function has no way to know what the
2545 * old value was... could consider this a FIXME...*/
2546 if (current != next)
2547 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2549 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2551 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2552 "%s: setting state from %s to %s",
2553 (next != state ? "intermediate" : "final"),
2554 gst_element_state_get_name (current), gst_element_state_get_name (next));
2556 /* now signal any waiters, they will error since the cookie was incremented */
2557 GST_STATE_BROADCAST (element);
2559 GST_OBJECT_UNLOCK (element);
2561 ret = gst_element_change_state (element, transition);
2563 GST_STATE_UNLOCK (element);
2565 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2566 gst_element_state_change_return_get_name (ret));
2572 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2573 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2574 "element was busy with async state change");
2575 GST_OBJECT_UNLOCK (element);
2577 GST_STATE_UNLOCK (element);
2579 return GST_STATE_CHANGE_ASYNC;
2584 * gst_element_change_state:
2585 * @element: a #GstElement
2586 * @transition: the requested transition
2588 * Perform @transition on @element.
2590 * This function must be called with STATE_LOCK held and is mainly used
2593 * Returns: the #GstStateChangeReturn of the state transition.
2595 GstStateChangeReturn
2596 gst_element_change_state (GstElement * element, GstStateChange transition)
2598 GstElementClass *oclass;
2599 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2601 oclass = GST_ELEMENT_GET_CLASS (element);
2603 /* call the state change function so it can set the state */
2604 if (oclass->change_state)
2605 ret = (oclass->change_state) (element, transition);
2607 ret = GST_STATE_CHANGE_FAILURE;
2610 case GST_STATE_CHANGE_FAILURE:
2611 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2612 "have FAILURE change_state return");
2613 /* state change failure */
2614 gst_element_abort_state (element);
2616 case GST_STATE_CHANGE_ASYNC:
2620 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2621 "element will change state ASYNC");
2623 target = GST_STATE_TARGET (element);
2625 if (target > GST_STATE_READY)
2628 /* else we just continue the state change downwards */
2629 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2630 "forcing commit state %s <= %s",
2631 gst_element_state_get_name (target),
2632 gst_element_state_get_name (GST_STATE_READY));
2634 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2637 case GST_STATE_CHANGE_SUCCESS:
2638 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2639 "element changed state SUCCESS");
2640 /* we can commit the state now which will proceeed to
2642 ret = gst_element_continue_state (element, ret);
2644 case GST_STATE_CHANGE_NO_PREROLL:
2645 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2646 "element changed state NO_PREROLL");
2647 /* we can commit the state now which will proceeed to
2649 ret = gst_element_continue_state (element, ret);
2652 goto invalid_return;
2655 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2660 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2668 GST_OBJECT_LOCK (element);
2669 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2670 g_critical ("%s: unknown return value %d from a state change function",
2671 GST_ELEMENT_NAME (element), ret);
2673 /* we are in error now */
2674 ret = GST_STATE_CHANGE_FAILURE;
2675 GST_STATE_RETURN (element) = ret;
2676 GST_OBJECT_UNLOCK (element);
2682 /* gst_iterator_fold functions for pads_activate
2683 * Stop the iterator if activating one pad failed. */
2685 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2687 GstPad *pad = g_value_get_object (vpad);
2688 gboolean cont = TRUE;
2690 if (!(cont = gst_pad_set_active (pad, *active)))
2691 g_value_set_boolean (ret, FALSE);
2696 /* returns false on error or early cutout of the fold, true if all
2697 * pads in @iter were (de)activated successfully. */
2699 iterator_activate_fold_with_resync (GstIterator * iter,
2700 GstIteratorFoldFunction func, gpointer user_data)
2702 GstIteratorResult ires;
2705 /* no need to unset this later, it's just a boolean */
2706 g_value_init (&ret, G_TYPE_BOOLEAN);
2707 g_value_set_boolean (&ret, TRUE);
2710 ires = gst_iterator_fold (iter, func, &ret, user_data);
2712 case GST_ITERATOR_RESYNC:
2713 /* need to reset the result again */
2714 g_value_set_boolean (&ret, TRUE);
2715 gst_iterator_resync (iter);
2717 case GST_ITERATOR_DONE:
2718 /* all pads iterated, return collected value */
2721 /* iterator returned _ERROR or premature end with _OK,
2722 * mark an error and exit */
2723 g_value_set_boolean (&ret, FALSE);
2728 /* return collected value */
2729 return g_value_get_boolean (&ret);
2732 /* is called with STATE_LOCK
2734 * Pads are activated from source pads to sinkpads.
2737 gst_element_pads_activate (GstElement * element, gboolean active)
2742 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2743 "%s pads", active ? "activate" : "deactivate");
2745 iter = gst_element_iterate_src_pads (element);
2747 iterator_activate_fold_with_resync (iter,
2748 (GstIteratorFoldFunction) activate_pads, &active);
2749 gst_iterator_free (iter);
2750 if (G_UNLIKELY (!res))
2753 iter = gst_element_iterate_sink_pads (element);
2755 iterator_activate_fold_with_resync (iter,
2756 (GstIteratorFoldFunction) activate_pads, &active);
2757 gst_iterator_free (iter);
2758 if (G_UNLIKELY (!res))
2761 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2762 "pad %sactivation successful", active ? "" : "de");
2769 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2770 "pad %sactivation failed", active ? "" : "de");
2775 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2776 "sink pads_activate failed");
2781 /* is called with STATE_LOCK */
2782 static GstStateChangeReturn
2783 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2785 GstState state, next;
2786 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2788 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2790 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2791 next = GST_STATE_TRANSITION_NEXT (transition);
2793 /* if the element already is in the given state, we just return success */
2794 if (next == GST_STATE_VOID_PENDING || state == next)
2797 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2798 "default handler tries setting state from %s to %s (%04x)",
2799 gst_element_state_get_name (state),
2800 gst_element_state_get_name (next), transition);
2802 switch (transition) {
2803 case GST_STATE_CHANGE_NULL_TO_READY:
2805 case GST_STATE_CHANGE_READY_TO_PAUSED:
2806 if (!gst_element_pads_activate (element, TRUE)) {
2807 result = GST_STATE_CHANGE_FAILURE;
2810 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2812 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2814 case GST_STATE_CHANGE_PAUSED_TO_READY:
2815 case GST_STATE_CHANGE_READY_TO_NULL:
2816 /* deactivate pads in both cases, since they are activated on
2817 ready->paused but the element might not have made it to paused */
2818 if (!gst_element_pads_activate (element, FALSE)) {
2819 result = GST_STATE_CHANGE_FAILURE;
2823 /* this will catch real but unhandled state changes;
2824 * can only be caused by:
2825 * - a new state was added
2826 * - somehow the element was asked to jump across an intermediate state
2828 g_warning ("Unhandled state change from %s to %s",
2829 gst_element_state_get_name (state),
2830 gst_element_state_get_name (next));
2837 GST_OBJECT_LOCK (element);
2838 result = GST_STATE_RETURN (element);
2839 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2840 "element is already in the %s state",
2841 gst_element_state_get_name (state));
2842 GST_OBJECT_UNLOCK (element);
2849 * gst_element_get_factory:
2850 * @element: a #GstElement to request the element factory of.
2852 * Retrieves the factory that was used to create this element.
2854 * Returns: (transfer none): the #GstElementFactory used for creating this
2855 * element. no refcounting is needed.
2858 gst_element_get_factory (GstElement * element)
2860 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2862 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2866 gst_element_dispose (GObject * object)
2868 GstElement *element = GST_ELEMENT_CAST (object);
2871 GstElementClass *oclass;
2874 oclass = GST_ELEMENT_GET_CLASS (element);
2876 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2878 if (GST_STATE (element) != GST_STATE_NULL)
2881 /* start by releasing all request pads, this might also remove some dynamic
2883 walk = element->pads;
2885 GstPad *pad = GST_PAD_CAST (walk->data);
2889 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
2890 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
2891 == GST_PAD_REQUEST) {
2892 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2893 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2894 oclass->release_pad (element, pad);
2896 /* in case the release_pad function removed the next pad too */
2897 if (walk && g_list_position (element->pads, walk) == -1)
2898 walk = element->pads;
2901 /* remove the remaining pads */
2902 while (element->pads) {
2903 GstPad *pad = GST_PAD_CAST (element->pads->data);
2904 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2905 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2906 if (!gst_element_remove_pad (element, pad)) {
2907 /* only happens when someone unparented our pad.. */
2908 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2913 GST_OBJECT_LOCK (element);
2914 clock_p = &element->clock;
2915 bus_p = &element->bus;
2916 gst_object_replace ((GstObject **) clock_p, NULL);
2917 gst_object_replace ((GstObject **) bus_p, NULL);
2918 gst_context_replace (&element->context, NULL);
2919 GST_OBJECT_UNLOCK (element);
2921 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2923 G_OBJECT_CLASS (parent_class)->dispose (object);
2932 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2934 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2936 "You need to explicitly set elements to the NULL state before\n"
2937 "dropping the final reference, to allow them to clean up.\n"
2938 "This problem may also be caused by a refcounting bug in the\n"
2939 "application or some element.\n",
2940 GST_OBJECT_NAME (element),
2941 gst_element_state_get_name (GST_STATE (element)),
2942 is_locked ? " (locked)" : "");
2948 gst_element_finalize (GObject * object)
2950 GstElement *element = GST_ELEMENT_CAST (object);
2952 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2954 g_cond_clear (&element->state_cond);
2955 g_rec_mutex_clear (&element->state_lock);
2957 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2959 G_OBJECT_CLASS (parent_class)->finalize (object);
2963 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2967 g_return_if_fail (GST_IS_ELEMENT (element));
2969 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2971 GST_OBJECT_LOCK (element);
2972 bus_p = &GST_ELEMENT_BUS (element);
2973 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2974 GST_OBJECT_UNLOCK (element);
2978 * gst_element_set_bus:
2979 * @element: a #GstElement to set the bus of.
2980 * @bus: (transfer none): the #GstBus to set.
2982 * Sets the bus of the element. Increases the refcount on the bus.
2983 * For internal use only, unless you're testing elements.
2988 gst_element_set_bus (GstElement * element, GstBus * bus)
2990 GstElementClass *oclass;
2992 g_return_if_fail (GST_IS_ELEMENT (element));
2994 oclass = GST_ELEMENT_GET_CLASS (element);
2996 if (oclass->set_bus)
2997 oclass->set_bus (element, bus);
3001 * gst_element_get_bus:
3002 * @element: a #GstElement to get the bus of.
3004 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3005 * bus for the application.
3007 * Returns: (transfer full): the element's #GstBus. unref after usage.
3012 gst_element_get_bus (GstElement * element)
3014 GstBus *result = NULL;
3016 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3018 GST_OBJECT_LOCK (element);
3019 if ((result = GST_ELEMENT_BUS (element)))
3020 gst_object_ref (result);
3021 GST_OBJECT_UNLOCK (element);
3023 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3030 gst_element_set_context_func (GstElement * element, GstContext * context)
3032 GST_OBJECT_LOCK (element);
3033 gst_context_replace (&element->context, context);
3034 GST_OBJECT_UNLOCK (element);
3038 * gst_element_set_context:
3039 * @element: a #GstElement to set the context of.
3040 * @context: (transfer none): the #GstContext to set.
3042 * Sets the context of the element. Increases the refcount of the context.
3047 gst_element_set_context (GstElement * element, GstContext * context)
3049 GstElementClass *oclass;
3051 g_return_if_fail (GST_IS_ELEMENT (element));
3053 oclass = GST_ELEMENT_GET_CLASS (element);
3055 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3056 "set context %p %" GST_PTR_FORMAT, context,
3057 gst_context_get_structure (context));
3059 if (oclass->set_context)
3060 oclass->set_context (element, context);
3064 * gst_element_get_context:
3065 * @element: a #GstElement to get the context from.
3067 * Gets the current context of the element.
3071 * Returns: (transfer full): The current context of the element
3074 gst_element_get_context (GstElement * element)
3076 GstContext *context = NULL;
3078 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
3080 GST_OBJECT_LOCK (element);
3081 if (element->context)
3082 context = gst_context_ref (element->context);
3083 GST_OBJECT_UNLOCK (element);
3085 return context ? context : gst_context_new ();