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.
47 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
49 * Elements can be linked through their pads.
50 * If the link is straightforward, use the gst_element_link()
51 * convenience function to link two elements, or gst_element_link_many()
52 * for more elements in a row.
53 * Use gst_element_link_filtered() to link two elements constrained by
54 * a specified set of #GstCaps.
55 * For finer control, use gst_element_link_pads() and
56 * gst_element_link_pads_filtered() to specify the pads to link on
57 * each element by name.
59 * Each element has a state (see #GstState). You can get and set the state
60 * of an element with gst_element_get_state() and gst_element_set_state().
61 * Setting a state triggers a #GstStateChange. To get a string representation
62 * of a #GstState, use gst_element_state_get_name().
64 * You can get and set a #GstClock on an element using gst_element_get_clock()
65 * and gst_element_set_clock().
66 * Some elements can provide a clock for the pipeline if
67 * the #GST_ELEMENT_FLAG_PROVIDE_CLOCK flag is set. With the
68 * gst_element_provide_clock() method one can retrieve the clock provided by
70 * Not all elements require a clock to operate correctly. If the
71 * #GST_ELEMENT_FLAG_REQUIRE_CLOCK() flag is set, a clock should be set on the
72 * element with gst_element_set_clock().
74 * Note that clock selection and distribution is normally handled by the
75 * toplevel #GstPipeline so the clock functions are only to be used in very
76 * specific situations.
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstelementmetadata.h"
86 #include "gstenumtypes.h"
94 #include "gst-i18n-lib.h"
95 #include "glib-compat-private.h"
97 #ifndef GST_DISABLE_GST_DEBUG
98 #include "printf/printf.h"
101 /* Element signals and args */
117 static void gst_element_class_init (GstElementClass * klass);
118 static void gst_element_init (GstElement * element);
119 static void gst_element_base_class_init (gpointer g_class);
120 static void gst_element_base_class_finalize (gpointer g_class);
122 static void gst_element_dispose (GObject * object);
123 static void gst_element_finalize (GObject * object);
125 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
126 GstStateChange transition);
127 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
128 GstState * state, GstState * pending, GstClockTime timeout);
129 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
131 static gboolean gst_element_set_clock_func (GstElement * element,
133 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
134 static gboolean gst_element_post_message_default (GstElement * element,
135 GstMessage * message);
137 static gboolean gst_element_default_send_event (GstElement * element,
139 static gboolean gst_element_default_query (GstElement * element,
142 static GstPadTemplate
143 * gst_element_class_get_request_pad_template (GstElementClass *
144 element_class, const gchar * name);
146 static GstObjectClass *parent_class = NULL;
147 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
149 /* this is used in gstelementfactory.c:gst_element_register() */
150 GQuark __gst_elementclass_factory = 0;
153 gst_element_get_type (void)
155 static volatile gsize gst_element_type = 0;
157 if (g_once_init_enter (&gst_element_type)) {
159 static const GTypeInfo element_info = {
160 sizeof (GstElementClass),
161 gst_element_base_class_init,
162 gst_element_base_class_finalize,
163 (GClassInitFunc) gst_element_class_init,
168 (GInstanceInitFunc) gst_element_init,
172 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
173 &element_info, G_TYPE_FLAG_ABSTRACT);
175 __gst_elementclass_factory =
176 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
177 g_once_init_leave (&gst_element_type, _type);
179 return gst_element_type;
183 gst_element_class_init (GstElementClass * klass)
185 GObjectClass *gobject_class;
187 gobject_class = (GObjectClass *) klass;
189 parent_class = g_type_class_peek_parent (klass);
192 * GstElement::pad-added:
193 * @gstelement: the object which received the signal
194 * @new_pad: the pad that has been added
196 * a new #GstPad has been added to the element. Note that this signal will
197 * usually be emitted from the context of the streaming thread. Also keep in
198 * mind that if you add new elements to the pipeline in the signal handler
199 * you will need to set them to the desired target state with
200 * gst_element_set_state() or gst_element_sync_state_with_parent().
202 gst_element_signals[PAD_ADDED] =
203 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
204 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
205 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
207 * GstElement::pad-removed:
208 * @gstelement: the object which received the signal
209 * @old_pad: the pad that has been removed
211 * a #GstPad has been removed from the element
213 gst_element_signals[PAD_REMOVED] =
214 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
215 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
216 g_cclosure_marshal_generic, G_TYPE_NONE, 1, GST_TYPE_PAD);
218 * GstElement::no-more-pads:
219 * @gstelement: the object which received the signal
221 * This signals that the element will not generate more dynamic pads.
222 * Note that this signal will usually be emitted from the context of
223 * the streaming thread.
225 gst_element_signals[NO_MORE_PADS] =
226 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
227 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
228 NULL, g_cclosure_marshal_generic, G_TYPE_NONE, 0);
230 gobject_class->dispose = gst_element_dispose;
231 gobject_class->finalize = gst_element_finalize;
233 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
234 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
235 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
236 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
237 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
238 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
239 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
240 klass->numpadtemplates = 0;
241 klass->post_message = GST_DEBUG_FUNCPTR (gst_element_post_message_default);
243 klass->elementfactory = NULL;
247 gst_element_base_class_init (gpointer g_class)
249 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
250 GList *node, *padtemplates;
252 /* Copy the element details here so elements can inherit the
253 * details from their base class and classes only need to set
254 * the details in class_init instead of base_init */
255 element_class->metadata =
256 element_class->metadata ? gst_structure_copy (element_class->metadata) :
257 gst_structure_new_empty ("metadata");
259 /* Copy the pad templates so elements inherit them
260 * from their base class but elements can add pad templates in class_init
261 * instead of base_init.
263 padtemplates = g_list_copy (element_class->padtemplates);
264 for (node = padtemplates; node != NULL; node = node->next) {
265 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
266 gst_object_ref (tmpl);
268 element_class->padtemplates = padtemplates;
270 /* set the factory, see gst_element_register() */
271 element_class->elementfactory =
272 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
273 __gst_elementclass_factory);
274 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "type %s : factory %p",
275 G_OBJECT_CLASS_NAME (element_class), element_class->elementfactory);
279 gst_element_base_class_finalize (gpointer g_class)
281 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
283 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
284 g_list_free (klass->padtemplates);
286 gst_structure_free (klass->metadata);
290 gst_element_init (GstElement * element)
292 GST_STATE (element) = GST_STATE_NULL;
293 GST_STATE_TARGET (element) = GST_STATE_NULL;
294 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
295 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
296 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
298 g_rec_mutex_init (&element->state_lock);
299 g_cond_init (&element->state_cond);
303 * gst_element_release_request_pad:
304 * @element: a #GstElement to release the request pad of.
305 * @pad: the #GstPad to release.
307 * Makes the element free the previously requested pad as obtained
308 * with gst_element_request_pad().
310 * This does not unref the pad. If the pad was created by using
311 * gst_element_request_pad(), gst_element_release_request_pad() needs to be
312 * followed by gst_object_unref() to free the @pad.
317 gst_element_release_request_pad (GstElement * element, GstPad * pad)
319 GstElementClass *oclass;
321 g_return_if_fail (GST_IS_ELEMENT (element));
322 g_return_if_fail (GST_IS_PAD (pad));
323 g_return_if_fail (GST_PAD_PAD_TEMPLATE (pad) == NULL ||
324 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad)) ==
327 oclass = GST_ELEMENT_GET_CLASS (element);
329 /* if the element implements a custom release function we call that, else we
330 * simply remove the pad from the element */
331 if (oclass->release_pad)
332 oclass->release_pad (element, pad);
334 gst_element_remove_pad (element, pad);
338 * gst_element_provide_clock:
339 * @element: a #GstElement to query
341 * Get the clock provided by the given element.
342 * <note>An element is only required to provide a clock in the PAUSED
343 * state. Some elements can provide a clock in other states.</note>
345 * Returns: (transfer full): the GstClock provided by the element or %NULL
346 * if no clock could be provided. Unref after usage.
351 gst_element_provide_clock (GstElement * element)
353 GstClock *result = NULL;
354 GstElementClass *oclass;
356 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
358 oclass = GST_ELEMENT_GET_CLASS (element);
360 if (oclass->provide_clock)
361 result = oclass->provide_clock (element);
367 gst_element_set_clock_func (GstElement * element, GstClock * clock)
371 GST_OBJECT_LOCK (element);
372 clock_p = &element->clock;
373 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
374 GST_OBJECT_UNLOCK (element);
380 * gst_element_set_clock:
381 * @element: a #GstElement to set the clock for.
382 * @clock: the #GstClock to set for the element.
384 * Sets the clock for the element. This function increases the
385 * refcount on the clock. Any previously set clock on the object
388 * Returns: %TRUE if the element accepted the clock. An element can refuse a
389 * clock when it, for example, is not able to slave its internal clock to the
390 * @clock or when it requires a specific clock to operate.
395 gst_element_set_clock (GstElement * element, GstClock * clock)
397 GstElementClass *oclass;
398 gboolean res = FALSE;
400 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
401 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
403 oclass = GST_ELEMENT_GET_CLASS (element);
405 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
407 if (oclass->set_clock)
408 res = oclass->set_clock (element, clock);
414 * gst_element_get_clock:
415 * @element: a #GstElement to get the clock of.
417 * Gets the currently configured clock of the element. This is the clock as was
418 * last set with gst_element_set_clock().
420 * Returns: (transfer full): the #GstClock of the element. unref after usage.
425 gst_element_get_clock (GstElement * element)
429 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
431 GST_OBJECT_LOCK (element);
432 if ((result = element->clock))
433 gst_object_ref (result);
434 GST_OBJECT_UNLOCK (element);
440 * gst_element_set_base_time:
441 * @element: a #GstElement.
442 * @time: the base time to set.
444 * Set the base time of an element. See gst_element_get_base_time().
449 gst_element_set_base_time (GstElement * element, GstClockTime time)
453 g_return_if_fail (GST_IS_ELEMENT (element));
455 GST_OBJECT_LOCK (element);
456 old = element->base_time;
457 element->base_time = time;
458 GST_OBJECT_UNLOCK (element);
460 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
461 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
462 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
466 * gst_element_get_base_time:
467 * @element: a #GstElement.
469 * Returns the base time of the element. The base time is the
470 * absolute time of the clock when this element was last put to
471 * PLAYING. Subtracting the base time from the clock time gives
472 * the running time of the element.
474 * Returns: the base time of the element.
479 gst_element_get_base_time (GstElement * element)
483 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
485 GST_OBJECT_LOCK (element);
486 result = element->base_time;
487 GST_OBJECT_UNLOCK (element);
493 * gst_element_set_start_time:
494 * @element: a #GstElement.
495 * @time: the base time to set.
497 * Set the start time of an element. The start time of the element is the
498 * running time of the element when it last went to the PAUSED state. In READY
499 * or after a flushing seek, it is set to 0.
501 * Toplevel elements like #GstPipeline will manage the start_time and
502 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
503 * on such a toplevel element will disable the distribution of the base_time to
504 * the children and can be useful if the application manages the base_time
505 * itself, for example if you want to synchronize capture from multiple
506 * pipelines, and you can also ensure that the pipelines have the same clock.
511 gst_element_set_start_time (GstElement * element, GstClockTime time)
515 g_return_if_fail (GST_IS_ELEMENT (element));
517 GST_OBJECT_LOCK (element);
518 old = GST_ELEMENT_START_TIME (element);
519 GST_ELEMENT_START_TIME (element) = time;
520 GST_OBJECT_UNLOCK (element);
522 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
523 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
524 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
528 * gst_element_get_start_time:
529 * @element: a #GstElement.
531 * Returns the start time of the element. The start time is the
532 * running time of the clock when this element was last put to PAUSED.
534 * Usually the start_time is managed by a toplevel element such as
539 * Returns: the start time of the element.
542 gst_element_get_start_time (GstElement * element)
546 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
548 GST_OBJECT_LOCK (element);
549 result = GST_ELEMENT_START_TIME (element);
550 GST_OBJECT_UNLOCK (element);
557 * gst_element_set_index:
558 * @element: a #GstElement.
559 * @index: (transfer none): a #GstIndex.
561 * Set @index on the element. The refcount of the index
562 * will be increased, any previously set index is unreffed.
567 gst_element_set_index (GstElement * element, GstIndex * index)
569 GstElementClass *oclass;
571 g_return_if_fail (GST_IS_ELEMENT (element));
572 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
574 oclass = GST_ELEMENT_GET_CLASS (element);
576 if (oclass->set_index)
577 oclass->set_index (element, index);
581 * gst_element_get_index:
582 * @element: a #GstElement.
584 * Gets the index from the element.
586 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
587 * element. unref after usage.
592 gst_element_get_index (GstElement * element)
594 GstElementClass *oclass;
595 GstIndex *result = NULL;
597 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
599 oclass = GST_ELEMENT_GET_CLASS (element);
601 if (oclass->get_index)
602 result = oclass->get_index (element);
609 * gst_element_add_pad:
610 * @element: a #GstElement to add the pad to.
611 * @pad: (transfer full): the #GstPad to add to the element.
613 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
614 * see gst_object_set_parent() for refcounting information.
616 * Pads are not automatically activated so elements should perform the needed
617 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
618 * state. See gst_pad_set_active() for more information about activating pads.
620 * The pad and the element should be unlocked when calling this function.
622 * This function will emit the #GstElement::pad-added signal on the element.
624 * Returns: %TRUE if the pad could be added. This function can fail when
625 * a pad with the same name already existed or the pad already had another
631 gst_element_add_pad (GstElement * element, GstPad * pad)
636 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
637 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
639 /* locking pad to look at the name */
640 GST_OBJECT_LOCK (pad);
641 pad_name = g_strdup (GST_PAD_NAME (pad));
642 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
643 GST_STR_NULL (pad_name));
644 flushing = GST_PAD_IS_FLUSHING (pad);
645 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
646 GST_OBJECT_UNLOCK (pad);
648 /* then check to see if there's already a pad by that name here */
649 GST_OBJECT_LOCK (element);
650 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
653 /* try to set the pad's parent */
654 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
655 GST_OBJECT_CAST (element))))
658 /* check for flushing pads */
659 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
660 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
661 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
662 "use gst_pad_set_active(pad,TRUE) before adding it.",
663 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
665 GST_OBJECT_LOCK (pad);
666 GST_PAD_UNSET_FLUSHING (pad);
667 GST_OBJECT_UNLOCK (pad);
672 /* add it to the list */
673 switch (gst_pad_get_direction (pad)) {
675 element->srcpads = g_list_append (element->srcpads, pad);
676 element->numsrcpads++;
679 element->sinkpads = g_list_append (element->sinkpads, pad);
680 element->numsinkpads++;
685 element->pads = g_list_append (element->pads, pad);
687 element->pads_cookie++;
688 GST_OBJECT_UNLOCK (element);
690 /* emit the PAD_ADDED signal */
691 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
698 g_critical ("Padname %s is not unique in element %s, not adding",
699 pad_name, GST_ELEMENT_NAME (element));
700 GST_OBJECT_UNLOCK (element);
707 ("Pad %s already has parent when trying to add to element %s",
708 pad_name, GST_ELEMENT_NAME (element));
709 GST_OBJECT_UNLOCK (element);
715 GST_OBJECT_LOCK (pad);
717 ("Trying to add pad %s to element %s, but it has no direction",
718 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
719 GST_OBJECT_UNLOCK (pad);
720 GST_OBJECT_UNLOCK (element);
726 * gst_element_remove_pad:
727 * @element: a #GstElement to remove pad from.
728 * @pad: (transfer full): the #GstPad to remove from the element.
730 * Removes @pad from @element. @pad will be destroyed if it has not been
731 * referenced elsewhere using gst_object_unparent().
733 * This function is used by plugin developers and should not be used
734 * by applications. Pads that were dynamically requested from elements
735 * with gst_element_request_pad() should be released with the
736 * gst_element_release_request_pad() function instead.
738 * Pads are not automatically deactivated so elements should perform the needed
739 * steps to deactivate the pad in case this pad is removed in the PAUSED or
740 * PLAYING state. See gst_pad_set_active() for more information about
743 * The pad and the element should be unlocked when calling this function.
745 * This function will emit the #GstElement::pad-removed signal on the element.
747 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
748 * pad does not belong to the provided element.
753 gst_element_remove_pad (GstElement * element, GstPad * pad)
757 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
758 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
760 /* locking pad to look at the name and parent */
761 GST_OBJECT_LOCK (pad);
762 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
763 GST_STR_NULL (GST_PAD_NAME (pad)));
765 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
767 GST_OBJECT_UNLOCK (pad);
770 if ((peer = gst_pad_get_peer (pad))) {
771 /* window for MT unsafeness, someone else could unlink here
772 * and then we call unlink with wrong pads. The unlink
773 * function would catch this and safely return failed. */
774 if (GST_PAD_IS_SRC (pad))
775 gst_pad_unlink (pad, peer);
777 gst_pad_unlink (peer, pad);
779 gst_object_unref (peer);
782 GST_OBJECT_LOCK (element);
783 /* remove it from the list */
784 switch (gst_pad_get_direction (pad)) {
786 element->srcpads = g_list_remove (element->srcpads, pad);
787 element->numsrcpads--;
790 element->sinkpads = g_list_remove (element->sinkpads, pad);
791 element->numsinkpads--;
794 g_critical ("Removing pad without direction???");
797 element->pads = g_list_remove (element->pads, pad);
798 GST_OBJECT_FLAG_UNSET (pad, GST_PAD_FLAG_NEED_PARENT);
800 element->pads_cookie++;
801 GST_OBJECT_UNLOCK (element);
803 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
804 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
806 gst_object_unparent (GST_OBJECT_CAST (pad));
813 /* locking order is element > pad */
814 GST_OBJECT_UNLOCK (pad);
816 GST_OBJECT_LOCK (element);
817 GST_OBJECT_LOCK (pad);
818 g_critical ("Padname %s:%s does not belong to element %s when removing",
819 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
820 GST_OBJECT_UNLOCK (pad);
821 GST_OBJECT_UNLOCK (element);
827 * gst_element_no_more_pads:
828 * @element: a #GstElement
830 * Use this function to signal that the element does not expect any more pads
831 * to show up in the current pipeline. This function should be called whenever
832 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
833 * pad templates use this in combination with autopluggers to figure out that
834 * the element is done initializing its pads.
836 * This function emits the #GstElement::no-more-pads signal.
841 gst_element_no_more_pads (GstElement * element)
843 g_return_if_fail (GST_IS_ELEMENT (element));
845 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
849 pad_compare_name (GstPad * pad1, const gchar * name)
853 GST_OBJECT_LOCK (pad1);
854 result = strcmp (GST_PAD_NAME (pad1), name);
855 GST_OBJECT_UNLOCK (pad1);
861 * gst_element_get_static_pad:
862 * @element: a #GstElement to find a static pad of.
863 * @name: the name of the static #GstPad to retrieve.
865 * Retrieves a pad from @element by name. This version only retrieves
866 * already-existing (i.e. 'static') pads.
868 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
874 gst_element_get_static_pad (GstElement * element, const gchar * name)
877 GstPad *result = NULL;
879 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
880 g_return_val_if_fail (name != NULL, NULL);
882 GST_OBJECT_LOCK (element);
884 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
886 result = GST_PAD_CAST (find->data);
887 gst_object_ref (result);
890 if (result == NULL) {
891 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
892 name, GST_ELEMENT_NAME (element));
894 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
895 GST_ELEMENT_NAME (element), name);
897 GST_OBJECT_UNLOCK (element);
903 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
904 const gchar * name, const GstCaps * caps)
906 GstPad *newpad = NULL;
907 GstElementClass *oclass;
909 oclass = GST_ELEMENT_GET_CLASS (element);
911 #ifndef G_DISABLE_CHECKS
912 /* Some sanity checking here */
916 /* Is this the template name? */
917 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
918 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
920 const gchar *str, *data;
923 /* Otherwise check if it's a valid name for the name template */
924 str = strchr (templ->name_template, '%');
925 g_return_val_if_fail (str != NULL, NULL);
926 g_return_val_if_fail (strncmp (templ->name_template, name,
927 str - templ->name_template) == 0, NULL);
928 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
930 data = name + (str - templ->name_template);
932 /* Can either be %s or %d or %u, do sanity checking for %d */
933 if (*(str + 1) == 'd') {
937 tmp = g_ascii_strtoll (data, &endptr, 10);
938 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
939 && *endptr == '\0', NULL);
940 } else if (*(str + 1) == 'u') {
944 tmp = g_ascii_strtoull (data, &endptr, 10);
945 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
949 pad = gst_element_get_static_pad (element, name);
951 gst_object_unref (pad);
952 /* FIXME 0.11: Change this to g_return_val_if_fail() */
953 g_critical ("Element %s already has a pad named %s, the behaviour of "
954 " gst_element_get_request_pad() for existing pads is undefined!",
955 GST_ELEMENT_NAME (element), name);
960 if (oclass->request_new_pad)
961 newpad = (oclass->request_new_pad) (element, templ, name, caps);
964 gst_object_ref (newpad);
970 * gst_element_get_request_pad:
971 * @element: a #GstElement to find a request pad of.
972 * @name: the name of the request #GstPad to retrieve.
974 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
975 * retrieves request pads. The pad should be released with
976 * gst_element_release_request_pad().
978 * This method is slow and will be deprecated in the future. New code should
979 * use gst_element_request_pad() with the requested template.
981 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
982 * Release after usage.
985 gst_element_get_request_pad (GstElement * element, const gchar * name)
987 GstPadTemplate *templ = NULL;
989 const gchar *req_name = NULL;
990 gboolean templ_found = FALSE;
993 gchar *str, *endptr = NULL;
994 GstElementClass *class;
996 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
997 g_return_val_if_fail (name != NULL, NULL);
999 class = GST_ELEMENT_GET_CLASS (element);
1001 /* if the name contains a %, we assume it's the complete template name. Get
1002 * the template and try to get a pad */
1003 if (strstr (name, "%")) {
1004 templ = gst_element_class_get_request_pad_template (class, name);
1009 /* there is no % in the name, try to find a matching template */
1010 list = class->padtemplates;
1011 while (!templ_found && list) {
1012 templ = (GstPadTemplate *) list->data;
1013 if (templ->presence == GST_PAD_REQUEST) {
1014 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1015 templ->name_template);
1016 /* see if we find an exact match */
1017 if (strcmp (name, templ->name_template) == 0) {
1022 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1023 and %d and %u, occurring at the end of the name_template, are the only
1025 else if ((str = strchr (templ->name_template, '%'))
1026 && strncmp (templ->name_template, name,
1027 str - templ->name_template) == 0
1028 && strlen (name) > str - templ->name_template) {
1029 data = name + (str - templ->name_template);
1030 if (*(str + 1) == 'd') {
1034 tmp = strtol (data, &endptr, 10);
1035 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1041 } else if (*(str + 1) == 'u') {
1045 tmp = strtoul (data, &endptr, 10);
1046 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1066 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1072 * gst_element_request_pad:
1073 * @element: a #GstElement to find a request pad of.
1074 * @templ: a #GstPadTemplate of which we want a pad of.
1075 * @name: (transfer none) (allow-none): the name of the request #GstPad
1076 * to retrieve. Can be %NULL.
1077 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1078 * request. Can be %NULL.
1080 * Retrieves a request pad from the element according to the provided template.
1081 * Pad templates can be looked up using
1082 * gst_element_factory_get_static_pad_templates().
1084 * The pad should be released with gst_element_release_request_pad().
1086 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1087 * Release after usage.
1090 gst_element_request_pad (GstElement * element,
1091 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1093 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1094 g_return_val_if_fail (templ != NULL, NULL);
1095 g_return_val_if_fail (templ->presence == GST_PAD_REQUEST, NULL);
1097 return _gst_element_request_pad (element, templ, name, caps);
1100 static GstIterator *
1101 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1103 GstIterator *result;
1105 GST_OBJECT_LOCK (element);
1106 result = gst_iterator_new_list (GST_TYPE_PAD,
1107 GST_OBJECT_GET_LOCK (element),
1108 &element->pads_cookie, padlist, (GObject *) element, NULL);
1109 GST_OBJECT_UNLOCK (element);
1115 * gst_element_iterate_pads:
1116 * @element: a #GstElement to iterate pads of.
1118 * Retrieves an iterator of @element's pads. The iterator should
1119 * be freed after usage. Also more specialized iterators exists such as
1120 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1122 * The order of pads returned by the iterator will be the order in which
1123 * the pads were added to the element.
1125 * Returns: (transfer full): the #GstIterator of #GstPad.
1130 gst_element_iterate_pads (GstElement * element)
1132 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1134 return gst_element_iterate_pad_list (element, &element->pads);
1138 * gst_element_iterate_src_pads:
1139 * @element: a #GstElement.
1141 * Retrieves an iterator of @element's source pads.
1143 * The order of pads returned by the iterator will be the order in which
1144 * the pads were added to the element.
1146 * Returns: (transfer full): the #GstIterator of #GstPad.
1151 gst_element_iterate_src_pads (GstElement * element)
1153 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1155 return gst_element_iterate_pad_list (element, &element->srcpads);
1159 * gst_element_iterate_sink_pads:
1160 * @element: a #GstElement.
1162 * Retrieves an iterator of @element's sink pads.
1164 * The order of pads returned by the iterator will be the order in which
1165 * the pads were added to the element.
1167 * Returns: (transfer full): the #GstIterator of #GstPad.
1172 gst_element_iterate_sink_pads (GstElement * element)
1174 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1176 return gst_element_iterate_pad_list (element, &element->sinkpads);
1180 * gst_element_class_add_pad_template:
1181 * @klass: the #GstElementClass to add the pad template to.
1182 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1184 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1185 * functions of classes. If a pad template with the same name as an already
1186 * existing one is added the old one is replaced by the new one.
1190 gst_element_class_add_pad_template (GstElementClass * klass,
1191 GstPadTemplate * templ)
1193 GList *template_list = klass->padtemplates;
1195 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1196 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1198 /* If we already have a pad template with the same name replace the
1200 while (template_list) {
1201 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1203 /* Found pad with the same name, replace and return */
1204 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1205 gst_object_unref (padtempl);
1206 template_list->data = templ;
1209 template_list = g_list_next (template_list);
1212 /* Take ownership of the floating ref */
1213 gst_object_ref_sink (templ);
1215 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1216 klass->numpadtemplates++;
1220 * gst_element_class_add_metadata:
1221 * @klass: class to set metadata for
1222 * @key: the key to set
1223 * @value: the value to set
1225 * Set @key with @value as metadata in @klass.
1228 gst_element_class_add_metadata (GstElementClass * klass,
1229 const gchar * key, const gchar * value)
1231 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1232 g_return_if_fail (key != NULL);
1233 g_return_if_fail (value != NULL);
1235 gst_structure_set ((GstStructure *) klass->metadata,
1236 key, G_TYPE_STRING, value, NULL);
1240 * gst_element_class_add_static_metadata:
1241 * @klass: class to set metadata for
1242 * @key: the key to set
1243 * @value: the value to set
1245 * Set @key with @value as metadata in @klass.
1247 * Same as gst_element_class_add_metadata(), but @value must be a static string
1248 * or an inlined string, as it will not be copied. (GStreamer plugins will
1249 * be made resident once loaded, so this function can be used even from
1250 * dynamically loaded plugins.)
1253 gst_element_class_add_static_metadata (GstElementClass * klass,
1254 const gchar * key, const gchar * value)
1256 GValue val = G_VALUE_INIT;
1258 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1259 g_return_if_fail (key != NULL);
1260 g_return_if_fail (value != NULL);
1262 g_value_init (&val, G_TYPE_STRING);
1263 g_value_set_static_string (&val, value);
1264 gst_structure_take_value ((GstStructure *) klass->metadata, key, &val);
1268 * gst_element_class_set_metadata:
1269 * @klass: class to set metadata for
1270 * @longname: The long English name of the element. E.g. "File Sink"
1271 * @classification: String describing the type of element, as an unordered list
1272 * separated with slashes ('/'). See draft-klass.txt of the design docs
1273 * for more details and common types. E.g: "Sink/File"
1274 * @description: Sentence describing the purpose of the element.
1275 * E.g: "Write stream to a file"
1276 * @author: Name and contact details of the author(s). Use \n to separate
1277 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1279 * Sets the detailed information for a #GstElementClass.
1280 * <note>This function is for use in _class_init functions only.</note>
1283 gst_element_class_set_metadata (GstElementClass * klass,
1284 const gchar * longname, const gchar * classification,
1285 const gchar * description, const gchar * author)
1287 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1288 g_return_if_fail (longname != NULL && *longname != '\0');
1289 g_return_if_fail (classification != NULL && *classification != '\0');
1290 g_return_if_fail (description != NULL && *description != '\0');
1291 g_return_if_fail (author != NULL && *author != '\0');
1293 gst_structure_id_set ((GstStructure *) klass->metadata,
1294 GST_QUARK (ELEMENT_METADATA_LONGNAME), G_TYPE_STRING, longname,
1295 GST_QUARK (ELEMENT_METADATA_KLASS), G_TYPE_STRING, classification,
1296 GST_QUARK (ELEMENT_METADATA_DESCRIPTION), G_TYPE_STRING, description,
1297 GST_QUARK (ELEMENT_METADATA_AUTHOR), G_TYPE_STRING, author, NULL);
1301 * gst_element_class_set_static_metadata:
1302 * @klass: class to set metadata for
1303 * @longname: The long English name of the element. E.g. "File Sink"
1304 * @classification: String describing the type of element, as an unordered list
1305 * separated with slashes ('/'). See draft-klass.txt of the design docs
1306 * for more details and common types. E.g: "Sink/File"
1307 * @description: Sentence describing the purpose of the element.
1308 * E.g: "Write stream to a file"
1309 * @author: Name and contact details of the author(s). Use \n to separate
1310 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1312 * Sets the detailed information for a #GstElementClass.
1313 * <note>This function is for use in _class_init functions only.</note>
1315 * Same as gst_element_class_set_metadata(), but @longname, @classification,
1316 * @description, and @author must be static strings or inlined strings, as
1317 * they will not be copied. (GStreamer plugins will be made resident once
1318 * loaded, so this function can be used even from dynamically loaded plugins.)
1321 gst_element_class_set_static_metadata (GstElementClass * klass,
1322 const gchar * longname, const gchar * classification,
1323 const gchar * description, const gchar * author)
1325 GstStructure *s = (GstStructure *) klass->metadata;
1326 GValue val = G_VALUE_INIT;
1328 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1329 g_return_if_fail (longname != NULL && *longname != '\0');
1330 g_return_if_fail (classification != NULL && *classification != '\0');
1331 g_return_if_fail (description != NULL && *description != '\0');
1332 g_return_if_fail (author != NULL && *author != '\0');
1334 g_value_init (&val, G_TYPE_STRING);
1336 g_value_set_static_string (&val, longname);
1337 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_LONGNAME), &val);
1339 g_value_set_static_string (&val, classification);
1340 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_KLASS), &val);
1342 g_value_set_static_string (&val, description);
1343 gst_structure_id_set_value (s, GST_QUARK (ELEMENT_METADATA_DESCRIPTION),
1346 g_value_set_static_string (&val, author);
1347 gst_structure_id_take_value (s, GST_QUARK (ELEMENT_METADATA_AUTHOR), &val);
1351 * gst_element_class_get_metadata:
1352 * @klass: class to get metadata for
1353 * @key: the key to get
1355 * Get metadata with @key in @klass.
1357 * Returns: the metadata for @key.
1360 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1362 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1363 g_return_val_if_fail (key != NULL, NULL);
1365 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1369 * gst_element_class_get_pad_template_list:
1370 * @element_class: a #GstElementClass to get pad templates of.
1372 * Retrieves a list of the pad templates associated with @element_class. The
1373 * list must not be modified by the calling code.
1374 * <note>If you use this function in the #GInstanceInitFunc of an object class
1375 * that has subclasses, make sure to pass the g_class parameter of the
1376 * #GInstanceInitFunc here.</note>
1378 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1382 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1384 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1386 return element_class->padtemplates;
1390 * gst_element_class_get_pad_template:
1391 * @element_class: a #GstElementClass to get the pad template of.
1392 * @name: the name of the #GstPadTemplate to get.
1394 * Retrieves a padtemplate from @element_class with the given name.
1395 * <note>If you use this function in the #GInstanceInitFunc of an object class
1396 * that has subclasses, make sure to pass the g_class parameter of the
1397 * #GInstanceInitFunc here.</note>
1399 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1400 * if none was found. No unreferencing is necessary.
1403 gst_element_class_get_pad_template (GstElementClass *
1404 element_class, const gchar * name)
1408 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1409 g_return_val_if_fail (name != NULL, NULL);
1411 padlist = element_class->padtemplates;
1414 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1416 if (strcmp (padtempl->name_template, name) == 0)
1419 padlist = g_list_next (padlist);
1425 static GstPadTemplate *
1426 gst_element_class_get_request_pad_template (GstElementClass *
1427 element_class, const gchar * name)
1429 GstPadTemplate *tmpl;
1431 tmpl = gst_element_class_get_pad_template (element_class, name);
1432 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1438 /* get a random pad on element of the given direction.
1439 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1442 gst_element_get_random_pad (GstElement * element,
1443 gboolean need_linked, GstPadDirection dir)
1445 GstPad *result = NULL;
1448 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1452 GST_OBJECT_LOCK (element);
1453 pads = element->srcpads;
1456 GST_OBJECT_LOCK (element);
1457 pads = element->sinkpads;
1460 goto wrong_direction;
1462 for (; pads; pads = g_list_next (pads)) {
1463 GstPad *pad = GST_PAD_CAST (pads->data);
1465 GST_OBJECT_LOCK (pad);
1466 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1467 GST_DEBUG_PAD_NAME (pad));
1469 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1470 /* if we require a linked pad, and it is not linked, continue the
1472 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1473 GST_DEBUG_PAD_NAME (pad));
1474 GST_OBJECT_UNLOCK (pad);
1477 /* found a pad, stop search */
1478 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1479 GST_DEBUG_PAD_NAME (pad));
1480 GST_OBJECT_UNLOCK (pad);
1486 gst_object_ref (result);
1488 GST_OBJECT_UNLOCK (element);
1492 /* ERROR handling */
1495 g_warning ("unknown pad direction %d", dir);
1501 gst_element_default_send_event (GstElement * element, GstEvent * event)
1503 gboolean result = FALSE;
1506 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1507 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1508 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1511 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1512 "pushing %s event to random %s pad %s:%s",
1513 GST_EVENT_TYPE_NAME (event),
1514 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1515 GST_DEBUG_PAD_NAME (pad));
1517 result = gst_pad_push_event (pad, event);
1518 gst_object_unref (pad);
1520 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1521 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1522 gst_event_unref (event);
1528 * gst_element_send_event:
1529 * @element: a #GstElement to send the event to.
1530 * @event: (transfer full): the #GstEvent to send to the element.
1532 * Sends an event to an element. If the element doesn't implement an
1533 * event handler, the event will be pushed on a random linked sink pad for
1534 * upstream events or a random linked source pad for downstream events.
1536 * This function takes ownership of the provided event so you should
1537 * gst_event_ref() it if you want to reuse the event after this call.
1541 * Returns: %TRUE if the event was handled. Events that trigger a preroll (such
1542 * as flushing seeks and steps) will emit %GST_MESSAGE_ASYNC_DONE.
1545 gst_element_send_event (GstElement * element, GstEvent * event)
1547 GstElementClass *oclass;
1548 gboolean result = FALSE;
1550 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1551 g_return_val_if_fail (event != NULL, FALSE);
1553 oclass = GST_ELEMENT_GET_CLASS (element);
1555 GST_STATE_LOCK (element);
1556 if (oclass->send_event) {
1557 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1558 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1559 result = oclass->send_event (element, event);
1561 GST_STATE_UNLOCK (element);
1568 * @element: a #GstElement to send the event to.
1569 * @rate: The new playback rate
1570 * @format: The format of the seek values
1571 * @flags: The optional seek flags.
1572 * @start_type: The type and flags for the new start position
1573 * @start: The value of the new start position
1574 * @stop_type: The type and flags for the new stop position
1575 * @stop: The value of the new stop position
1577 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1578 * the parameters. The seek event is sent to the element using
1579 * gst_element_send_event().
1583 * Returns: %TRUE if the event was handled. Flushing seeks will trigger a
1584 * preroll, which will emit %GST_MESSAGE_ASYNC_DONE.
1587 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1588 GstSeekFlags flags, GstSeekType start_type, gint64 start,
1589 GstSeekType stop_type, gint64 stop)
1594 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1597 gst_event_new_seek (rate, format, flags, start_type, start, stop_type,
1599 result = gst_element_send_event (element, event);
1605 gst_element_default_query (GstElement * element, GstQuery * query)
1607 gboolean result = FALSE;
1610 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1612 result = gst_pad_query (pad, query);
1614 gst_object_unref (pad);
1616 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1618 GstPad *peer = gst_pad_get_peer (pad);
1621 result = gst_pad_query (peer, query);
1623 gst_object_unref (peer);
1625 gst_object_unref (pad);
1632 * gst_element_query:
1633 * @element: a #GstElement to perform the query on.
1634 * @query: (transfer none): the #GstQuery.
1636 * Performs a query on the given element.
1638 * For elements that don't implement a query handler, this function
1639 * forwards the query to a random srcpad or to the peer of a
1640 * random linked sinkpad of this element.
1642 * Please note that some queries might need a running pipeline to work.
1644 * Returns: %TRUE if the query could be performed.
1649 gst_element_query (GstElement * element, GstQuery * query)
1651 GstElementClass *klass;
1653 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1654 g_return_val_if_fail (query != NULL, FALSE);
1656 klass = GST_ELEMENT_GET_CLASS (element);
1658 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1659 GST_ELEMENT_NAME (element));
1660 return klass->query (element, query);
1667 gst_element_post_message_default (GstElement * element, GstMessage * message)
1670 gboolean result = FALSE;
1672 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1673 g_return_val_if_fail (message != NULL, FALSE);
1675 GST_OBJECT_LOCK (element);
1678 if (G_UNLIKELY (bus == NULL))
1681 gst_object_ref (bus);
1682 GST_OBJECT_UNLOCK (element);
1684 /* we release the element lock when posting the message so that any
1685 * (synchronous) message handlers can operate on the element */
1686 result = gst_bus_post (bus, message);
1687 gst_object_unref (bus);
1694 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1695 "not posting message %p: no bus", message);
1696 GST_OBJECT_UNLOCK (element);
1697 gst_message_unref (message);
1703 * gst_element_post_message:
1704 * @element: a #GstElement posting the message
1705 * @message: (transfer full): a #GstMessage to post
1707 * Post a message on the element's #GstBus. This function takes ownership of the
1708 * message; if you want to access the message after this call, you should add an
1709 * additional reference before calling.
1711 * Returns: %TRUE if the message was successfully posted. The function returns
1712 * %FALSE if the element did not have a bus.
1717 gst_element_post_message (GstElement * element, GstMessage * message)
1719 GstElementClass *klass;
1721 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1722 g_return_val_if_fail (message != NULL, FALSE);
1724 klass = GST_ELEMENT_GET_CLASS (element);
1725 if (klass->post_message)
1726 return klass->post_message (element, message);
1732 * _gst_element_error_printf:
1733 * @format: the printf-like format to use, or %NULL
1735 * This function is only used internally by the gst_element_error() macro.
1737 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1743 _gst_element_error_printf (const gchar * format, ...)
1754 va_start (args, format);
1756 len = __gst_vasprintf (&buffer, format, args);
1767 * gst_element_message_full:
1768 * @element: a #GstElement to send message from
1769 * @type: the #GstMessageType
1770 * @domain: the GStreamer GError domain this message belongs to
1771 * @code: the GError code belonging to the domain
1772 * @text: (allow-none) (transfer full): an allocated text string to be used
1773 * as a replacement for the default message connected to code,
1775 * @debug: (allow-none) (transfer full): an allocated debug message to be
1776 * used as a replacement for the default debugging information,
1778 * @file: the source code file where the error was generated
1779 * @function: the source code function where the error was generated
1780 * @line: the source code line where the error was generated
1782 * Post an error, warning or info message on the bus from inside an element.
1784 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1785 * #GST_MESSAGE_INFO.
1789 void gst_element_message_full
1790 (GstElement * element, GstMessageType type,
1791 GQuark domain, gint code, gchar * text,
1792 gchar * debug, const gchar * file, const gchar * function, gint line)
1794 GError *gerror = NULL;
1798 gboolean has_debug = TRUE;
1799 GstMessage *message = NULL;
1802 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1803 g_return_if_fail (GST_IS_ELEMENT (element));
1804 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1805 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1807 /* check if we send the given text or the default error text */
1808 if ((text == NULL) || (text[0] == 0)) {
1809 /* text could have come from g_strdup_printf (""); */
1811 sent_text = gst_error_get_message (domain, code);
1815 /* construct a sent_debug with extra information from source */
1816 if ((debug == NULL) || (debug[0] == 0)) {
1817 /* debug could have come from g_strdup_printf (""); */
1821 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1823 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1824 file, line, function, name, debug);
1826 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1827 file, line, function, name);
1831 /* create gerror and post message */
1832 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1834 gerror = g_error_new_literal (domain, code, sent_text);
1837 case GST_MESSAGE_ERROR:
1839 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1841 case GST_MESSAGE_WARNING:
1842 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1845 case GST_MESSAGE_INFO:
1846 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1850 g_assert_not_reached ();
1853 gst_element_post_message (element, message);
1855 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1856 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1859 g_error_free (gerror);
1860 g_free (sent_debug);
1865 * gst_element_is_locked_state:
1866 * @element: a #GstElement.
1868 * Checks if the state of an element is locked.
1869 * If the state of an element is locked, state changes of the parent don't
1870 * affect the element.
1871 * This way you can leave currently unused elements inside bins. Just lock their
1872 * state before changing the state from #GST_STATE_NULL.
1876 * Returns: %TRUE, if the element's state is locked.
1879 gst_element_is_locked_state (GstElement * element)
1883 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1885 GST_OBJECT_LOCK (element);
1886 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1887 GST_OBJECT_UNLOCK (element);
1893 * gst_element_set_locked_state:
1894 * @element: a #GstElement
1895 * @locked_state: %TRUE to lock the element's state
1897 * Locks the state of an element, so state changes of the parent don't affect
1898 * this element anymore.
1902 * Returns: %TRUE if the state was changed, %FALSE if bad parameters were given
1903 * or the elements state-locking needed no change.
1906 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1910 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1912 GST_OBJECT_LOCK (element);
1913 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1915 if (G_UNLIKELY (old == locked_state))
1919 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1920 GST_ELEMENT_NAME (element));
1921 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1923 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1924 GST_ELEMENT_NAME (element));
1925 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1927 GST_OBJECT_UNLOCK (element);
1933 GST_CAT_DEBUG (GST_CAT_STATES,
1934 "elements %s was already in locked state %d",
1935 GST_ELEMENT_NAME (element), old);
1936 GST_OBJECT_UNLOCK (element);
1943 * gst_element_sync_state_with_parent:
1944 * @element: a #GstElement.
1946 * Tries to change the state of the element to the same as its parent.
1947 * If this function returns %FALSE, the state of element is undefined.
1949 * Returns: %TRUE, if the element's state could be synced to the parent's state.
1954 gst_element_sync_state_with_parent (GstElement * element)
1958 GstStateChangeReturn ret;
1960 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1962 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1963 GstState parent_current, parent_pending;
1965 GST_OBJECT_LOCK (parent);
1966 parent_current = GST_STATE (parent);
1967 parent_pending = GST_STATE_PENDING (parent);
1968 GST_OBJECT_UNLOCK (parent);
1970 /* set to pending if there is one, else we set it to the current state of
1972 if (parent_pending != GST_STATE_VOID_PENDING)
1973 target = parent_pending;
1975 target = parent_current;
1977 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1978 "syncing state (%s) to parent %s %s (%s, %s)",
1979 gst_element_state_get_name (GST_STATE (element)),
1980 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1981 gst_element_state_get_name (parent_current),
1982 gst_element_state_get_name (parent_pending));
1984 ret = gst_element_set_state (element, target);
1985 if (ret == GST_STATE_CHANGE_FAILURE)
1988 gst_object_unref (parent);
1992 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1999 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2000 "syncing state failed (%s)",
2001 gst_element_state_change_return_get_name (ret));
2002 gst_object_unref (parent);
2008 static GstStateChangeReturn
2009 gst_element_get_state_func (GstElement * element,
2010 GstState * state, GstState * pending, GstClockTime timeout)
2012 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
2013 GstState old_pending;
2015 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
2016 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
2018 GST_OBJECT_LOCK (element);
2019 ret = GST_STATE_RETURN (element);
2020 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
2021 gst_element_state_change_return_get_name (ret));
2023 /* we got an error, report immediately */
2024 if (ret == GST_STATE_CHANGE_FAILURE)
2027 /* we got no_preroll, report immediately */
2028 if (ret == GST_STATE_CHANGE_NO_PREROLL)
2031 /* no need to wait async if we are not async */
2032 if (ret != GST_STATE_CHANGE_ASYNC)
2035 old_pending = GST_STATE_PENDING (element);
2036 if (old_pending != GST_STATE_VOID_PENDING) {
2040 /* get cookie to detect state changes during waiting */
2041 cookie = element->state_cookie;
2043 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2044 "waiting for element to commit state");
2046 /* we have a pending state change, wait for it to complete */
2047 if (timeout != GST_CLOCK_TIME_NONE) {
2049 /* make timeout absolute */
2050 end_time = g_get_monotonic_time () + (timeout / 1000);
2051 signaled = GST_STATE_WAIT_UNTIL (element, end_time);
2053 GST_STATE_WAIT (element);
2058 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
2059 /* timeout triggered */
2060 ret = GST_STATE_CHANGE_ASYNC;
2062 if (cookie != element->state_cookie)
2065 /* could be success or failure */
2066 if (old_pending == GST_STATE (element)) {
2067 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
2068 ret = GST_STATE_CHANGE_SUCCESS;
2070 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2071 ret = GST_STATE_CHANGE_FAILURE;
2074 /* if nothing is pending anymore we can return SUCCESS */
2075 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2076 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2077 ret = GST_STATE_CHANGE_SUCCESS;
2083 *state = GST_STATE (element);
2085 *pending = GST_STATE_PENDING (element);
2087 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2088 "state current: %s, pending: %s, result: %s",
2089 gst_element_state_get_name (GST_STATE (element)),
2090 gst_element_state_get_name (GST_STATE_PENDING (element)),
2091 gst_element_state_change_return_get_name (ret));
2092 GST_OBJECT_UNLOCK (element);
2099 *state = GST_STATE_VOID_PENDING;
2101 *pending = GST_STATE_VOID_PENDING;
2103 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2105 GST_OBJECT_UNLOCK (element);
2107 return GST_STATE_CHANGE_FAILURE;
2112 * gst_element_get_state:
2113 * @element: a #GstElement to get the state of.
2114 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2116 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2117 * state. Can be %NULL.
2118 * @timeout: a #GstClockTime to specify the timeout for an async
2119 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2121 * Gets the state of the element.
2123 * For elements that performed an ASYNC state change, as reported by
2124 * gst_element_set_state(), this function will block up to the
2125 * specified timeout value for the state change to complete.
2126 * If the element completes the state change or goes into
2127 * an error, this function returns immediately with a return value of
2128 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2130 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2131 * returns the current and pending state immediately.
2133 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2134 * successfully changed its state but is not able to provide data yet.
2135 * This mostly happens for live sources that only produce data in
2136 * %GST_STATE_PLAYING. While the state change return is equivalent to
2137 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2138 * some sink elements might not be able to complete their state change because
2139 * an element is not producing data to complete the preroll. When setting the
2140 * element to playing, the preroll will complete and playback will start.
2142 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2143 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2144 * element is still performing a state change or
2145 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2149 GstStateChangeReturn
2150 gst_element_get_state (GstElement * element,
2151 GstState * state, GstState * pending, GstClockTime timeout)
2153 GstElementClass *oclass;
2154 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2156 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2158 oclass = GST_ELEMENT_GET_CLASS (element);
2160 if (oclass->get_state)
2161 result = (oclass->get_state) (element, state, pending, timeout);
2167 * gst_element_abort_state:
2168 * @element: a #GstElement to abort the state of.
2170 * Abort the state change of the element. This function is used
2171 * by elements that do asynchronous state changes and find out
2172 * something is wrong.
2174 * This function should be called with the STATE_LOCK held.
2179 gst_element_abort_state (GstElement * element)
2183 #ifndef GST_DISABLE_GST_DEBUG
2187 g_return_if_fail (GST_IS_ELEMENT (element));
2189 GST_OBJECT_LOCK (element);
2190 pending = GST_STATE_PENDING (element);
2192 if (pending == GST_STATE_VOID_PENDING ||
2193 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2194 goto nothing_aborted;
2196 #ifndef GST_DISABLE_GST_DEBUG
2197 old_state = GST_STATE (element);
2199 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2200 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2201 gst_element_state_get_name (pending));
2205 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2207 GST_STATE_BROADCAST (element);
2208 GST_OBJECT_UNLOCK (element);
2214 GST_OBJECT_UNLOCK (element);
2219 /* Not static because GstBin has manual state handling too */
2221 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2222 GstState newstate, GstState pending)
2224 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2225 GstMessage *message;
2227 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2228 "notifying about state-changed %s to %s (%s pending)",
2229 gst_element_state_get_name (oldstate),
2230 gst_element_state_get_name (newstate),
2231 gst_element_state_get_name (pending));
2233 if (klass->state_changed)
2234 klass->state_changed (element, oldstate, newstate, pending);
2236 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2237 oldstate, newstate, pending);
2238 gst_element_post_message (element, message);
2242 * gst_element_continue_state:
2243 * @element: a #GstElement to continue the state change of.
2244 * @ret: The previous state return value
2246 * Commit the state change of the element and proceed to the next
2247 * pending state if any. This function is used
2248 * by elements that do asynchronous state changes.
2249 * The core will normally call this method automatically when an
2250 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2252 * If after calling this method the element still has not reached
2253 * the pending state, the next state change is performed.
2255 * This method is used internally and should normally not be called by plugins
2258 * Returns: The result of the commit state change.
2262 GstStateChangeReturn
2263 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2265 GstStateChangeReturn old_ret;
2266 GstState old_state, old_next;
2267 GstState current, next, pending;
2268 GstStateChange transition;
2270 GST_OBJECT_LOCK (element);
2271 old_ret = GST_STATE_RETURN (element);
2272 GST_STATE_RETURN (element) = ret;
2273 pending = GST_STATE_PENDING (element);
2275 /* check if there is something to commit */
2276 if (pending == GST_STATE_VOID_PENDING)
2277 goto nothing_pending;
2279 old_state = GST_STATE (element);
2280 /* this is the state we should go to next */
2281 old_next = GST_STATE_NEXT (element);
2282 /* update current state */
2283 current = GST_STATE (element) = old_next;
2285 /* see if we reached the final state */
2286 if (pending == current)
2289 next = GST_STATE_GET_NEXT (current, pending);
2290 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2292 GST_STATE_NEXT (element) = next;
2294 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2295 GST_OBJECT_UNLOCK (element);
2297 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2298 "committing state from %s to %s, pending %s, next %s",
2299 gst_element_state_get_name (old_state),
2300 gst_element_state_get_name (old_next),
2301 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2303 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2305 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2306 "continue state change %s to %s, final %s",
2307 gst_element_state_get_name (current),
2308 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2310 ret = gst_element_change_state (element, transition);
2316 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2317 GST_OBJECT_UNLOCK (element);
2322 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2323 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2325 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2326 "completed state change to %s", gst_element_state_get_name (pending));
2327 GST_OBJECT_UNLOCK (element);
2329 /* don't post silly messages with the same state. This can happen
2330 * when an element state is changed to what it already was. For bins
2331 * this can be the result of a lost state, which we check with the
2332 * previous return value.
2333 * We do signal the cond though as a _get_state() might be blocking
2335 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2336 _priv_gst_element_state_changed (element, old_state, old_next,
2337 GST_STATE_VOID_PENDING);
2339 GST_STATE_BROADCAST (element);
2346 * gst_element_lost_state:
2347 * @element: a #GstElement the state is lost of
2349 * Brings the element to the lost state. The current state of the
2350 * element is copied to the pending state so that any call to
2351 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2353 * An ASYNC_START message is posted. If the element was PLAYING, it will
2354 * go to PAUSED. The element will be restored to its PLAYING state by
2355 * the parent pipeline when it prerolls again.
2357 * This is mostly used for elements that lost their preroll buffer
2358 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2359 * they will go to their pending state again when a new preroll buffer is
2360 * queued. This function can only be called when the element is currently
2361 * not in error or an async state change.
2363 * This function is used internally and should normally not be called from
2364 * plugins or applications.
2367 gst_element_lost_state (GstElement * element)
2369 GstState old_state, new_state;
2370 GstMessage *message;
2372 g_return_if_fail (GST_IS_ELEMENT (element));
2374 GST_OBJECT_LOCK (element);
2375 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2378 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2379 goto only_async_start;
2381 old_state = GST_STATE (element);
2383 /* when we were PLAYING, the new state is PAUSED. We will also not
2384 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2385 * when we preroll. */
2386 if (old_state > GST_STATE_PAUSED)
2387 new_state = GST_STATE_PAUSED;
2389 new_state = old_state;
2391 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2392 "lost state of %s to %s", gst_element_state_get_name (old_state),
2393 gst_element_state_get_name (new_state));
2395 GST_STATE (element) = new_state;
2396 GST_STATE_NEXT (element) = new_state;
2397 GST_STATE_PENDING (element) = new_state;
2398 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2399 GST_OBJECT_UNLOCK (element);
2401 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2403 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2404 gst_element_post_message (element, message);
2410 GST_OBJECT_UNLOCK (element);
2415 GST_OBJECT_UNLOCK (element);
2417 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2418 gst_element_post_message (element, message);
2424 * gst_element_set_state:
2425 * @element: a #GstElement to change state of.
2426 * @state: the element's new #GstState.
2428 * Sets the state of the element. This function will try to set the
2429 * requested state by going through all the intermediary states and calling
2430 * the class's state change function for each.
2432 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2433 * element will perform the remainder of the state change asynchronously in
2435 * An application can use gst_element_get_state() to wait for the completion
2436 * of the state change or it can wait for a %GST_MESSAGE_ASYNC_DONE or
2437 * %GST_MESSAGE_STATE_CHANGED on the bus.
2439 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2440 * #GST_STATE_CHANGE_ASYNC.
2442 * Returns: Result of the state change using #GstStateChangeReturn.
2446 GstStateChangeReturn
2447 gst_element_set_state (GstElement * element, GstState state)
2449 GstElementClass *oclass;
2450 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2452 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2454 oclass = GST_ELEMENT_GET_CLASS (element);
2456 if (oclass->set_state)
2457 result = (oclass->set_state) (element, state);
2463 * default set state function, calculates the next state based
2464 * on current state and calls the change_state function
2466 static GstStateChangeReturn
2467 gst_element_set_state_func (GstElement * element, GstState state)
2469 GstState current, next, old_pending;
2470 GstStateChangeReturn ret;
2471 GstStateChange transition;
2472 GstStateChangeReturn old_ret;
2474 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2476 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2477 gst_element_state_get_name (state));
2479 /* state lock is taken to protect the set_state() and get_state()
2480 * procedures, it does not lock any variables. */
2481 GST_STATE_LOCK (element);
2483 /* now calculate how to get to the new state */
2484 GST_OBJECT_LOCK (element);
2485 old_ret = GST_STATE_RETURN (element);
2486 /* previous state change returned an error, remove all pending
2487 * and next states */
2488 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2489 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2490 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2491 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2494 current = GST_STATE (element);
2495 next = GST_STATE_NEXT (element);
2496 old_pending = GST_STATE_PENDING (element);
2498 /* this is the (new) state we should go to. TARGET is the last state we set on
2500 if (state != GST_STATE_TARGET (element)) {
2501 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2502 "setting target state to %s", gst_element_state_get_name (state));
2503 GST_STATE_TARGET (element) = state;
2504 /* increment state cookie so that we can track each state change. We only do
2505 * this if this is actually a new state change. */
2506 element->state_cookie++;
2508 GST_STATE_PENDING (element) = state;
2510 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2511 "current %s, old_pending %s, next %s, old return %s",
2512 gst_element_state_get_name (current),
2513 gst_element_state_get_name (old_pending),
2514 gst_element_state_get_name (next),
2515 gst_element_state_change_return_get_name (old_ret));
2517 /* if the element was busy doing a state change, we just update the
2518 * target state, it'll get to it async then. */
2519 if (old_pending != GST_STATE_VOID_PENDING) {
2520 /* upwards state change will happen ASYNC */
2521 if (old_pending <= state)
2523 /* element is going to this state already */
2524 else if (next == state)
2526 /* element was performing an ASYNC upward state change and
2527 * we request to go downward again. Start from the next pending
2529 else if (next > state
2530 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2534 next = GST_STATE_GET_NEXT (current, state);
2535 /* now we store the next state */
2536 GST_STATE_NEXT (element) = next;
2537 /* mark busy, we need to check that there is actually a state change
2538 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2539 * the default element change_state function has no way to know what the
2540 * old value was... could consider this a FIXME...*/
2541 if (current != next)
2542 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2544 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2546 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2547 "%s: setting state from %s to %s",
2548 (next != state ? "intermediate" : "final"),
2549 gst_element_state_get_name (current), gst_element_state_get_name (next));
2551 /* now signal any waiters, they will error since the cookie was incremented */
2552 GST_STATE_BROADCAST (element);
2554 GST_OBJECT_UNLOCK (element);
2556 ret = gst_element_change_state (element, transition);
2558 GST_STATE_UNLOCK (element);
2560 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2561 gst_element_state_change_return_get_name (ret));
2567 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2568 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2569 "element was busy with async state change");
2570 GST_OBJECT_UNLOCK (element);
2572 GST_STATE_UNLOCK (element);
2574 return GST_STATE_CHANGE_ASYNC;
2579 * gst_element_change_state:
2580 * @element: a #GstElement
2581 * @transition: the requested transition
2583 * Perform @transition on @element.
2585 * This function must be called with STATE_LOCK held and is mainly used
2588 * Returns: the #GstStateChangeReturn of the state transition.
2590 GstStateChangeReturn
2591 gst_element_change_state (GstElement * element, GstStateChange transition)
2593 GstElementClass *oclass;
2594 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2596 oclass = GST_ELEMENT_GET_CLASS (element);
2598 /* call the state change function so it can set the state */
2599 if (oclass->change_state)
2600 ret = (oclass->change_state) (element, transition);
2602 ret = GST_STATE_CHANGE_FAILURE;
2605 case GST_STATE_CHANGE_FAILURE:
2606 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2607 "have FAILURE change_state return");
2608 /* state change failure */
2609 gst_element_abort_state (element);
2611 case GST_STATE_CHANGE_ASYNC:
2615 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2616 "element will change state ASYNC");
2618 target = GST_STATE_TARGET (element);
2620 if (target > GST_STATE_READY)
2623 /* else we just continue the state change downwards */
2624 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2625 "forcing commit state %s <= %s",
2626 gst_element_state_get_name (target),
2627 gst_element_state_get_name (GST_STATE_READY));
2629 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2632 case GST_STATE_CHANGE_SUCCESS:
2633 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2634 "element changed state SUCCESS");
2635 /* we can commit the state now which will proceeed to
2637 ret = gst_element_continue_state (element, ret);
2639 case GST_STATE_CHANGE_NO_PREROLL:
2640 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2641 "element changed state NO_PREROLL");
2642 /* we can commit the state now which will proceeed to
2644 ret = gst_element_continue_state (element, ret);
2647 goto invalid_return;
2650 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2655 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2663 GST_OBJECT_LOCK (element);
2664 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2665 g_critical ("%s: unknown return value %d from a state change function",
2666 GST_ELEMENT_NAME (element), ret);
2668 /* we are in error now */
2669 ret = GST_STATE_CHANGE_FAILURE;
2670 GST_STATE_RETURN (element) = ret;
2671 GST_OBJECT_UNLOCK (element);
2677 /* gst_iterator_fold functions for pads_activate
2678 * Stop the iterator if activating one pad failed. */
2680 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2682 GstPad *pad = g_value_get_object (vpad);
2683 gboolean cont = TRUE;
2685 if (!(cont = gst_pad_set_active (pad, *active)))
2686 g_value_set_boolean (ret, FALSE);
2691 /* returns false on error or early cutout of the fold, true if all
2692 * pads in @iter were (de)activated successfully. */
2694 iterator_activate_fold_with_resync (GstIterator * iter,
2695 GstIteratorFoldFunction func, gpointer user_data)
2697 GstIteratorResult ires;
2700 /* no need to unset this later, it's just a boolean */
2701 g_value_init (&ret, G_TYPE_BOOLEAN);
2702 g_value_set_boolean (&ret, TRUE);
2705 ires = gst_iterator_fold (iter, func, &ret, user_data);
2707 case GST_ITERATOR_RESYNC:
2708 /* need to reset the result again */
2709 g_value_set_boolean (&ret, TRUE);
2710 gst_iterator_resync (iter);
2712 case GST_ITERATOR_DONE:
2713 /* all pads iterated, return collected value */
2716 /* iterator returned _ERROR or premature end with _OK,
2717 * mark an error and exit */
2718 g_value_set_boolean (&ret, FALSE);
2723 /* return collected value */
2724 return g_value_get_boolean (&ret);
2727 /* is called with STATE_LOCK
2729 * Pads are activated from source pads to sinkpads.
2732 gst_element_pads_activate (GstElement * element, gboolean active)
2737 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2738 "%s pads", active ? "activate" : "deactivate");
2740 iter = gst_element_iterate_src_pads (element);
2742 iterator_activate_fold_with_resync (iter,
2743 (GstIteratorFoldFunction) activate_pads, &active);
2744 gst_iterator_free (iter);
2745 if (G_UNLIKELY (!res))
2748 iter = gst_element_iterate_sink_pads (element);
2750 iterator_activate_fold_with_resync (iter,
2751 (GstIteratorFoldFunction) activate_pads, &active);
2752 gst_iterator_free (iter);
2753 if (G_UNLIKELY (!res))
2756 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2757 "pad %sactivation successful", active ? "" : "de");
2764 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2765 "pad %sactivation failed", active ? "" : "de");
2770 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2771 "sink pads_activate failed");
2776 /* is called with STATE_LOCK */
2777 static GstStateChangeReturn
2778 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2780 GstState state, next;
2781 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2783 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2785 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2786 next = GST_STATE_TRANSITION_NEXT (transition);
2788 /* if the element already is in the given state, we just return success */
2789 if (next == GST_STATE_VOID_PENDING || state == next)
2792 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2793 "default handler tries setting state from %s to %s (%04x)",
2794 gst_element_state_get_name (state),
2795 gst_element_state_get_name (next), transition);
2797 switch (transition) {
2798 case GST_STATE_CHANGE_NULL_TO_READY:
2800 case GST_STATE_CHANGE_READY_TO_PAUSED:
2801 if (!gst_element_pads_activate (element, TRUE)) {
2802 result = GST_STATE_CHANGE_FAILURE;
2805 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2807 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2809 case GST_STATE_CHANGE_PAUSED_TO_READY:
2810 case GST_STATE_CHANGE_READY_TO_NULL:
2811 /* deactivate pads in both cases, since they are activated on
2812 ready->paused but the element might not have made it to paused */
2813 if (!gst_element_pads_activate (element, FALSE)) {
2814 result = GST_STATE_CHANGE_FAILURE;
2818 /* this will catch real but unhandled state changes;
2819 * can only be caused by:
2820 * - a new state was added
2821 * - somehow the element was asked to jump across an intermediate state
2823 g_warning ("Unhandled state change from %s to %s",
2824 gst_element_state_get_name (state),
2825 gst_element_state_get_name (next));
2832 GST_OBJECT_LOCK (element);
2833 result = GST_STATE_RETURN (element);
2834 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2835 "element is already in the %s state",
2836 gst_element_state_get_name (state));
2837 GST_OBJECT_UNLOCK (element);
2844 * gst_element_get_factory:
2845 * @element: a #GstElement to request the element factory of.
2847 * Retrieves the factory that was used to create this element.
2849 * Returns: (transfer none): the #GstElementFactory used for creating this
2850 * element. no refcounting is needed.
2853 gst_element_get_factory (GstElement * element)
2855 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2857 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2861 gst_element_dispose (GObject * object)
2863 GstElement *element = GST_ELEMENT_CAST (object);
2866 GstElementClass *oclass;
2869 oclass = GST_ELEMENT_GET_CLASS (element);
2871 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2873 if (GST_STATE (element) != GST_STATE_NULL)
2876 /* start by releasing all request pads, this might also remove some dynamic
2878 walk = element->pads;
2880 GstPad *pad = GST_PAD_CAST (walk->data);
2884 if (oclass->release_pad && GST_PAD_PAD_TEMPLATE (pad) &&
2885 GST_PAD_TEMPLATE_PRESENCE (GST_PAD_PAD_TEMPLATE (pad))
2886 == GST_PAD_REQUEST) {
2887 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2888 "removing request pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2889 oclass->release_pad (element, pad);
2891 /* in case the release_pad function removed the next pad too */
2892 if (walk && g_list_position (element->pads, walk) == -1)
2893 walk = element->pads;
2896 /* remove the remaining pads */
2897 while (element->pads) {
2898 GstPad *pad = GST_PAD_CAST (element->pads->data);
2899 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2900 "removing pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2901 if (!gst_element_remove_pad (element, pad)) {
2902 /* only happens when someone unparented our pad.. */
2903 g_critical ("failed to remove pad %s:%s", GST_DEBUG_PAD_NAME (pad));
2908 GST_OBJECT_LOCK (element);
2909 clock_p = &element->clock;
2910 bus_p = &element->bus;
2911 gst_object_replace ((GstObject **) clock_p, NULL);
2912 gst_object_replace ((GstObject **) bus_p, NULL);
2913 GST_OBJECT_UNLOCK (element);
2915 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2917 G_OBJECT_CLASS (parent_class)->dispose (object);
2926 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2928 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2930 "You need to explicitly set elements to the NULL state before\n"
2931 "dropping the final reference, to allow them to clean up.\n"
2932 "This problem may also be caused by a refcounting bug in the\n"
2933 "application or some element.\n",
2934 GST_OBJECT_NAME (element),
2935 gst_element_state_get_name (GST_STATE (element)),
2936 is_locked ? " (locked)" : "");
2942 gst_element_finalize (GObject * object)
2944 GstElement *element = GST_ELEMENT_CAST (object);
2946 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2948 g_cond_clear (&element->state_cond);
2949 g_rec_mutex_clear (&element->state_lock);
2951 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2953 G_OBJECT_CLASS (parent_class)->finalize (object);
2957 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2961 g_return_if_fail (GST_IS_ELEMENT (element));
2963 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2965 GST_OBJECT_LOCK (element);
2966 bus_p = &GST_ELEMENT_BUS (element);
2967 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2968 GST_OBJECT_UNLOCK (element);
2972 * gst_element_set_bus:
2973 * @element: a #GstElement to set the bus of.
2974 * @bus: (transfer none): the #GstBus to set.
2976 * Sets the bus of the element. Increases the refcount on the bus.
2977 * For internal use only, unless you're testing elements.
2982 gst_element_set_bus (GstElement * element, GstBus * bus)
2984 GstElementClass *oclass;
2986 g_return_if_fail (GST_IS_ELEMENT (element));
2988 oclass = GST_ELEMENT_GET_CLASS (element);
2990 if (oclass->set_bus)
2991 oclass->set_bus (element, bus);
2995 * gst_element_get_bus:
2996 * @element: a #GstElement to get the bus of.
2998 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2999 * bus for the application.
3001 * Returns: (transfer full): the element's #GstBus. unref after usage.
3006 gst_element_get_bus (GstElement * element)
3008 GstBus *result = NULL;
3010 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3012 GST_OBJECT_LOCK (element);
3013 if ((result = GST_ELEMENT_BUS (element)))
3014 gst_object_ref (result);
3015 GST_OBJECT_UNLOCK (element);
3017 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,
3024 * gst_element_set_context:
3025 * @element: a #GstElement to set the context of.
3026 * @context: (transfer none): the #GstContext to set.
3028 * Sets the context of the element. Increases the refcount of the context.
3033 gst_element_set_context (GstElement * element, GstContext * context)
3035 GstElementClass *oclass;
3037 g_return_if_fail (GST_IS_ELEMENT (element));
3039 oclass = GST_ELEMENT_GET_CLASS (element);
3041 GST_CAT_DEBUG_OBJECT (GST_CAT_CONTEXT, element,
3042 "set context %p %" GST_PTR_FORMAT, context,
3043 gst_context_get_structure (context));
3045 if (oclass->set_context)
3046 oclass->set_context (element, context);