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., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, 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 * All elements 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_\%d".
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 * gst_element_provides_clock() returns %TRUE. 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
72 * gst_element_requires_clock() returns %TRUE, 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 2009-05-29 (0.10.24)
82 /* FIXME 0.11: suppress warnings for deprecated API such as GStaticRecMutex
83 * with newer GLib versions (>= 2.31.0) */
84 #define GLIB_DISABLE_DEPRECATION_WARNINGS
85 #include "gst_private.h"
88 #include <gobject/gvaluecollector.h>
90 #include "gstelement.h"
91 #include "gstelementmetadata.h"
92 #include "gstenumtypes.h"
94 #include "gstmarshal.h"
100 #include "gst-i18n-lib.h"
101 #include "glib-compat-private.h"
103 /* Element signals and args */
119 static void gst_element_class_init (GstElementClass * klass);
120 static void gst_element_init (GstElement * element);
121 static void gst_element_base_class_init (gpointer g_class);
122 static void gst_element_base_class_finalize (gpointer g_class);
124 static void gst_element_dispose (GObject * object);
125 static void gst_element_finalize (GObject * object);
127 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
128 GstStateChange transition);
129 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
130 GstState * state, GstState * pending, GstClockTime timeout);
131 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
133 static gboolean gst_element_set_clock_func (GstElement * element,
135 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
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 gst_marshal_VOID__OBJECT, 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 gst_marshal_VOID__OBJECT, 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, gst_marshal_VOID__VOID, 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;
242 klass->elementfactory = NULL;
246 gst_element_base_class_init (gpointer g_class)
248 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
249 GList *node, *padtemplates;
251 /* Copy the element details here so elements can inherit the
252 * details from their base class and classes only need to set
253 * the details in class_init instead of base_init */
254 element_class->metadata =
255 element_class->metadata ? gst_structure_copy (element_class->metadata) :
256 gst_structure_new_empty ("metadata");
258 /* Copy the pad templates so elements inherit them
259 * from their base class but elements can add pad templates in class_init
260 * instead of base_init.
262 padtemplates = g_list_copy (element_class->padtemplates);
263 for (node = padtemplates; node != NULL; node = node->next) {
264 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
265 gst_object_ref (tmpl);
267 element_class->padtemplates = padtemplates;
269 /* set the factory, see gst_element_register() */
270 element_class->elementfactory =
271 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
272 __gst_elementclass_factory);
273 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
274 element_class->elementfactory);
278 gst_element_base_class_finalize (gpointer g_class)
280 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
282 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
283 g_list_free (klass->padtemplates);
285 gst_structure_free (klass->metadata);
289 gst_element_init (GstElement * element)
291 GST_STATE (element) = GST_STATE_NULL;
292 GST_STATE_TARGET (element) = GST_STATE_NULL;
293 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
294 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
295 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
297 g_static_rec_mutex_init (&element->state_lock);
298 element->state_cond = g_cond_new ();
302 * gst_element_release_request_pad:
303 * @element: a #GstElement to release the request pad of.
304 * @pad: the #GstPad to release.
306 * Makes the element free the previously requested pad as obtained
307 * with gst_element_get_request_pad().
309 * This does not unref the pad. If the pad was created by using
310 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
311 * followed by gst_object_unref() to free the @pad.
316 gst_element_release_request_pad (GstElement * element, GstPad * pad)
318 GstElementClass *oclass;
320 g_return_if_fail (GST_IS_ELEMENT (element));
321 g_return_if_fail (GST_IS_PAD (pad));
323 oclass = GST_ELEMENT_GET_CLASS (element);
325 /* if the element implements a custom release function we call that, else we
326 * simply remove the pad from the element */
327 if (oclass->release_pad)
328 (oclass->release_pad) (element, pad);
330 gst_element_remove_pad (element, pad);
334 * gst_element_provide_clock:
335 * @element: a #GstElement to query
337 * Get the clock provided by the given element.
338 * <note>An element is only required to provide a clock in the PAUSED
339 * state. Some elements can provide a clock in other states.</note>
341 * Returns: (transfer full): the GstClock provided by the element or %NULL
342 * if no clock could be provided. Unref after usage.
347 gst_element_provide_clock (GstElement * element)
349 GstClock *result = NULL;
350 GstElementClass *oclass;
352 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
354 oclass = GST_ELEMENT_GET_CLASS (element);
356 if (oclass->provide_clock)
357 result = oclass->provide_clock (element);
363 gst_element_set_clock_func (GstElement * element, GstClock * clock)
367 GST_OBJECT_LOCK (element);
368 clock_p = &element->clock;
369 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
370 GST_OBJECT_UNLOCK (element);
376 * gst_element_set_clock:
377 * @element: a #GstElement to set the clock for.
378 * @clock: the #GstClock to set for the element.
380 * Sets the clock for the element. This function increases the
381 * refcount on the clock. Any previously set clock on the object
384 * Returns: %TRUE if the element accepted the clock. An element can refuse a
385 * clock when it, for example, is not able to slave its internal clock to the
386 * @clock or when it requires a specific clock to operate.
391 gst_element_set_clock (GstElement * element, GstClock * clock)
393 GstElementClass *oclass;
394 gboolean res = FALSE;
396 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
397 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
399 oclass = GST_ELEMENT_GET_CLASS (element);
401 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
403 if (oclass->set_clock)
404 res = oclass->set_clock (element, clock);
410 * gst_element_get_clock:
411 * @element: a #GstElement to get the clock of.
413 * Gets the currently configured clock of the element. This is the clock as was
414 * last set with gst_element_set_clock().
416 * Returns: (transfer full): the #GstClock of the element. unref after usage.
421 gst_element_get_clock (GstElement * element)
425 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
427 GST_OBJECT_LOCK (element);
428 if ((result = element->clock))
429 gst_object_ref (result);
430 GST_OBJECT_UNLOCK (element);
436 * gst_element_set_base_time:
437 * @element: a #GstElement.
438 * @time: the base time to set.
440 * Set the base time of an element. See gst_element_get_base_time().
445 gst_element_set_base_time (GstElement * element, GstClockTime time)
449 g_return_if_fail (GST_IS_ELEMENT (element));
451 GST_OBJECT_LOCK (element);
452 old = element->base_time;
453 element->base_time = time;
454 GST_OBJECT_UNLOCK (element);
456 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
457 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
458 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
462 * gst_element_get_base_time:
463 * @element: a #GstElement.
465 * Returns the base time of the element. The base time is the
466 * absolute time of the clock when this element was last put to
467 * PLAYING. Subtracting the base time from the clock time gives
468 * the running time of the element.
470 * Returns: the base time of the element.
475 gst_element_get_base_time (GstElement * element)
479 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
481 GST_OBJECT_LOCK (element);
482 result = element->base_time;
483 GST_OBJECT_UNLOCK (element);
489 * gst_element_set_start_time:
490 * @element: a #GstElement.
491 * @time: the base time to set.
493 * Set the start time of an element. The start time of the element is the
494 * running time of the element when it last went to the PAUSED state. In READY
495 * or after a flushing seek, it is set to 0.
497 * Toplevel elements like #GstPipeline will manage the start_time and
498 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
499 * on such a toplevel element will disable the distribution of the base_time to
500 * the children and can be useful if the application manages the base_time
501 * itself, for example if you want to synchronize capture from multiple
502 * pipelines, and you can also ensure that the pipelines have the same clock.
509 gst_element_set_start_time (GstElement * element, GstClockTime time)
513 g_return_if_fail (GST_IS_ELEMENT (element));
515 GST_OBJECT_LOCK (element);
516 old = GST_ELEMENT_START_TIME (element);
517 GST_ELEMENT_START_TIME (element) = time;
518 GST_OBJECT_UNLOCK (element);
520 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
521 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
522 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
526 * gst_element_get_start_time:
527 * @element: a #GstElement.
529 * Returns the start time of the element. The start time is the
530 * running time of the clock when this element was last put to PAUSED.
532 * Usually the start_time is managed by a toplevel element such as
537 * 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);
556 * gst_element_set_index:
557 * @element: a #GstElement.
558 * @index: (transfer none): a #GstIndex.
560 * Set @index on the element. The refcount of the index
561 * will be increased, any previously set index is unreffed.
566 gst_element_set_index (GstElement * element, GstIndex * index)
568 GstElementClass *oclass;
570 g_return_if_fail (GST_IS_ELEMENT (element));
571 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
573 oclass = GST_ELEMENT_GET_CLASS (element);
575 if (oclass->set_index)
576 oclass->set_index (element, index);
580 * gst_element_get_index:
581 * @element: a #GstElement.
583 * Gets the index from the element.
585 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
586 * element. unref after usage.
591 gst_element_get_index (GstElement * element)
593 GstElementClass *oclass;
594 GstIndex *result = NULL;
596 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
598 oclass = GST_ELEMENT_GET_CLASS (element);
600 if (oclass->get_index)
601 result = oclass->get_index (element);
607 * gst_element_add_pad:
608 * @element: a #GstElement to add the pad to.
609 * @pad: (transfer full): the #GstPad to add to the element.
611 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
612 * see gst_object_set_parent() for refcounting information.
614 * Pads are not automatically activated so elements should perform the needed
615 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
616 * state. See gst_pad_set_active() for more information about activating pads.
618 * The pad and the element should be unlocked when calling this function.
620 * This function will emit the #GstElement::pad-added signal on the element.
622 * Returns: %TRUE if the pad could be added. This function can fail when
623 * a pad with the same name already existed or the pad already had another
629 gst_element_add_pad (GstElement * element, GstPad * pad)
634 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
635 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
637 /* locking pad to look at the name */
638 GST_OBJECT_LOCK (pad);
639 pad_name = g_strdup (GST_PAD_NAME (pad));
640 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
641 GST_STR_NULL (pad_name));
642 flushing = GST_PAD_IS_FLUSHING (pad);
643 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
644 GST_OBJECT_UNLOCK (pad);
646 /* then check to see if there's already a pad by that name here */
647 GST_OBJECT_LOCK (element);
648 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
651 /* try to set the pad's parent */
652 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
653 GST_OBJECT_CAST (element))))
656 /* check for flushing pads */
657 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
658 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
659 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
660 "use gst_pad_set_active(pad,TRUE) before adding it.",
661 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
663 GST_OBJECT_LOCK (pad);
664 GST_PAD_UNSET_FLUSHING (pad);
665 GST_OBJECT_UNLOCK (pad);
670 /* add it to the list */
671 switch (gst_pad_get_direction (pad)) {
673 element->srcpads = g_list_prepend (element->srcpads, pad);
674 element->numsrcpads++;
677 element->sinkpads = g_list_prepend (element->sinkpads, pad);
678 element->numsinkpads++;
683 element->pads = g_list_prepend (element->pads, pad);
685 element->pads_cookie++;
686 GST_OBJECT_UNLOCK (element);
688 /* emit the PAD_ADDED signal */
689 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
696 g_critical ("Padname %s is not unique in element %s, not adding",
697 pad_name, GST_ELEMENT_NAME (element));
698 GST_OBJECT_UNLOCK (element);
705 ("Pad %s already has parent when trying to add to element %s",
706 pad_name, GST_ELEMENT_NAME (element));
707 GST_OBJECT_UNLOCK (element);
713 GST_OBJECT_LOCK (pad);
715 ("Trying to add pad %s to element %s, but it has no direction",
716 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
717 GST_OBJECT_UNLOCK (pad);
718 GST_OBJECT_UNLOCK (element);
724 * gst_element_remove_pad:
725 * @element: a #GstElement to remove pad from.
726 * @pad: (transfer none): the #GstPad to remove from the element.
728 * Removes @pad from @element. @pad will be destroyed if it has not been
729 * referenced elsewhere using gst_object_unparent().
731 * This function is used by plugin developers and should not be used
732 * by applications. Pads that were dynamically requested from elements
733 * with gst_element_get_request_pad() should be released with the
734 * gst_element_release_request_pad() function instead.
736 * Pads are not automatically deactivated so elements should perform the needed
737 * steps to deactivate the pad in case this pad is removed in the PAUSED or
738 * PLAYING state. See gst_pad_set_active() for more information about
741 * The pad and the element should be unlocked when calling this function.
743 * This function will emit the #GstElement::pad-removed signal on the element.
745 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
746 * pad does not belong to the provided element.
751 gst_element_remove_pad (GstElement * element, GstPad * pad)
755 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
756 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
758 /* locking pad to look at the name and parent */
759 GST_OBJECT_LOCK (pad);
760 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
761 GST_STR_NULL (GST_PAD_NAME (pad)));
763 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
765 GST_OBJECT_UNLOCK (pad);
768 if ((peer = gst_pad_get_peer (pad))) {
769 /* window for MT unsafeness, someone else could unlink here
770 * and then we call unlink with wrong pads. The unlink
771 * function would catch this and safely return failed. */
772 if (GST_PAD_IS_SRC (pad))
773 gst_pad_unlink (pad, peer);
775 gst_pad_unlink (peer, pad);
777 gst_object_unref (peer);
780 GST_OBJECT_LOCK (element);
781 /* remove it from the list */
782 switch (gst_pad_get_direction (pad)) {
784 element->srcpads = g_list_remove (element->srcpads, pad);
785 element->numsrcpads--;
788 element->sinkpads = g_list_remove (element->sinkpads, pad);
789 element->numsinkpads--;
792 g_critical ("Removing pad without direction???");
795 element->pads = g_list_remove (element->pads, pad);
797 element->pads_cookie++;
798 GST_OBJECT_UNLOCK (element);
800 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
801 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
803 gst_object_unparent (GST_OBJECT_CAST (pad));
810 /* locking order is element > pad */
811 GST_OBJECT_UNLOCK (pad);
813 GST_OBJECT_LOCK (element);
814 GST_OBJECT_LOCK (pad);
815 g_critical ("Padname %s:%s does not belong to element %s when removing",
816 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
817 GST_OBJECT_UNLOCK (pad);
818 GST_OBJECT_UNLOCK (element);
824 * gst_element_no_more_pads:
825 * @element: a #GstElement
827 * Use this function to signal that the element does not expect any more pads
828 * to show up in the current pipeline. This function should be called whenever
829 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
830 * pad templates use this in combination with autopluggers to figure out that
831 * the element is done initializing its pads.
833 * This function emits the #GstElement::no-more-pads signal.
838 gst_element_no_more_pads (GstElement * element)
840 g_return_if_fail (GST_IS_ELEMENT (element));
842 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
846 pad_compare_name (GstPad * pad1, const gchar * name)
850 GST_OBJECT_LOCK (pad1);
851 result = strcmp (GST_PAD_NAME (pad1), name);
852 GST_OBJECT_UNLOCK (pad1);
858 * gst_element_get_static_pad:
859 * @element: a #GstElement to find a static pad of.
860 * @name: the name of the static #GstPad to retrieve.
862 * Retrieves a pad from @element by name. This version only retrieves
863 * already-existing (i.e. 'static') pads.
865 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
871 gst_element_get_static_pad (GstElement * element, const gchar * name)
874 GstPad *result = NULL;
876 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
877 g_return_val_if_fail (name != NULL, NULL);
879 GST_OBJECT_LOCK (element);
881 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
883 result = GST_PAD_CAST (find->data);
884 gst_object_ref (result);
887 if (result == NULL) {
888 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
889 name, GST_ELEMENT_NAME (element));
891 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
892 GST_ELEMENT_NAME (element), name);
894 GST_OBJECT_UNLOCK (element);
900 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
901 const gchar * name, const GstCaps * caps)
903 GstPad *newpad = NULL;
904 GstElementClass *oclass;
906 oclass = GST_ELEMENT_GET_CLASS (element);
908 #ifndef G_DISABLE_CHECKS
909 /* Some sanity checking here */
913 /* Is this the template name? */
914 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
915 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
917 const gchar *str, *data;
920 /* Otherwise check if it's a valid name for the name template */
921 str = strchr (templ->name_template, '%');
922 g_return_val_if_fail (str != NULL, NULL);
923 g_return_val_if_fail (strncmp (templ->name_template, name,
924 str - templ->name_template) == 0, NULL);
925 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
927 data = name + (str - templ->name_template);
929 /* Can either be %s or %d or %u, do sanity checking for %d */
930 if (*(str + 1) == 'd') {
934 tmp = g_ascii_strtoll (data, &endptr, 10);
935 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
936 && *endptr == '\0', NULL);
937 } else if (*(str + 1) == 'u') {
941 tmp = g_ascii_strtoull (data, &endptr, 10);
942 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
946 pad = gst_element_get_static_pad (element, name);
948 gst_object_unref (pad);
949 /* FIXME 0.11: Change this to g_return_val_if_fail() */
950 g_critical ("Element %s already has a pad named %s, the behaviour of "
951 " gst_element_get_request_pad() for existing pads is undefined!",
952 GST_ELEMENT_NAME (element), name);
957 if (oclass->request_new_pad)
958 newpad = (oclass->request_new_pad) (element, templ, name, caps);
961 gst_object_ref (newpad);
967 * gst_element_get_request_pad:
968 * @element: a #GstElement to find a request pad of.
969 * @name: the name of the request #GstPad to retrieve.
971 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
972 * retrieves request pads. The pad should be released with
973 * gst_element_release_request_pad().
975 * This method is slow and will be deprecated in the future. New code should
976 * use gst_element_request_pad() with the requested template.
978 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
979 * Release after usage.
982 gst_element_get_request_pad (GstElement * element, const gchar * name)
984 GstPadTemplate *templ = NULL;
986 const gchar *req_name = NULL;
987 gboolean templ_found = FALSE;
990 gchar *str, *endptr = NULL;
991 GstElementClass *class;
993 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
994 g_return_val_if_fail (name != NULL, NULL);
996 class = GST_ELEMENT_GET_CLASS (element);
998 /* if the name contains a %, we assume it's the complete template name. Get
999 * the template and try to get a pad */
1000 if (strstr (name, "%")) {
1001 templ = gst_element_class_get_request_pad_template (class, name);
1006 /* there is no % in the name, try to find a matching template */
1007 list = class->padtemplates;
1008 while (!templ_found && list) {
1009 templ = (GstPadTemplate *) list->data;
1010 if (templ->presence == GST_PAD_REQUEST) {
1011 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1012 templ->name_template);
1013 /* see if we find an exact match */
1014 if (strcmp (name, templ->name_template) == 0) {
1019 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1020 and %d and %u, occurring at the end of the name_template, are the only
1022 else if ((str = strchr (templ->name_template, '%'))
1023 && strncmp (templ->name_template, name,
1024 str - templ->name_template) == 0
1025 && strlen (name) > str - templ->name_template) {
1026 data = name + (str - templ->name_template);
1027 if (*(str + 1) == 'd') {
1031 tmp = strtol (data, &endptr, 10);
1032 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1038 } else if (*(str + 1) == 'u') {
1042 tmp = strtoul (data, &endptr, 10);
1043 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1063 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1069 * gst_element_request_pad:
1070 * @element: a #GstElement to find a request pad of.
1071 * @templ: a #GstPadTemplate of which we want a pad of.
1072 * @name: (transfer none) (allow-none): the name of the request #GstPad
1073 * to retrieve. Can be %NULL.
1074 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1075 * request. Can be %NULL.
1077 * Retrieves a request pad from the element according to the provided template.
1078 * Pad templates can be looked up using
1079 * gst_element_factory_get_static_pad_templates().
1081 * The pad should be released with gst_element_release_request_pad().
1083 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1084 * Release after usage.
1089 gst_element_request_pad (GstElement * element,
1090 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1092 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1093 g_return_val_if_fail (templ != NULL, NULL);
1095 return _gst_element_request_pad (element, templ, name, caps);
1098 static GstIterator *
1099 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1101 GstIterator *result;
1103 GST_OBJECT_LOCK (element);
1104 result = gst_iterator_new_list (GST_TYPE_PAD,
1105 GST_OBJECT_GET_LOCK (element),
1106 &element->pads_cookie, padlist, (GObject *) element, NULL);
1107 GST_OBJECT_UNLOCK (element);
1113 * gst_element_iterate_pads:
1114 * @element: a #GstElement to iterate pads of.
1116 * Retrieves an iterator of @element's pads. The iterator should
1117 * be freed after usage. Also more specialized iterators exists such as
1118 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1120 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1126 gst_element_iterate_pads (GstElement * element)
1128 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1130 return gst_element_iterate_pad_list (element, &element->pads);
1134 * gst_element_iterate_src_pads:
1135 * @element: a #GstElement.
1137 * Retrieves an iterator of @element's source pads.
1139 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1145 gst_element_iterate_src_pads (GstElement * element)
1147 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1149 return gst_element_iterate_pad_list (element, &element->srcpads);
1153 * gst_element_iterate_sink_pads:
1154 * @element: a #GstElement.
1156 * Retrieves an iterator of @element's sink pads.
1158 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1164 gst_element_iterate_sink_pads (GstElement * element)
1166 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1168 return gst_element_iterate_pad_list (element, &element->sinkpads);
1172 * gst_element_class_add_pad_template:
1173 * @klass: the #GstElementClass to add the pad template to.
1174 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1176 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1177 * functions of classes. If a pad template with the same name as an already
1178 * existing one is added the old one is replaced by the new one.
1182 gst_element_class_add_pad_template (GstElementClass * klass,
1183 GstPadTemplate * templ)
1185 GList *template_list = klass->padtemplates;
1187 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1188 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1190 /* If we already have a pad template with the same name replace the
1192 while (template_list) {
1193 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1195 /* Found pad with the same name, replace and return */
1196 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1197 gst_object_unref (padtempl);
1198 template_list->data = templ;
1201 template_list = g_list_next (template_list);
1204 /* Take ownership of the floating ref */
1205 gst_object_ref_sink (templ);
1207 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1208 klass->numpadtemplates++;
1212 * gst_element_class_add_metadata:
1213 * @klass: class to set metadata for
1214 * @key: the key to set
1215 * @value: the value to set
1217 * Set @key with @value as metadata in @klass.
1220 gst_element_class_add_metadata (GstElementClass * klass,
1221 const gchar * key, const gchar * value)
1223 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1224 g_return_if_fail (key != NULL);
1225 g_return_if_fail (value != NULL);
1227 gst_structure_set ((GstStructure *) klass->metadata,
1228 key, G_TYPE_STRING, value, NULL);
1232 * gst_element_class_set_metadata:
1233 * @klass: class to set metadata for
1234 * @longname: The long English name of the element. E.g. "File Sink"
1235 * @classification: String describing the type of element, as an unordered list
1236 * separated with slashes ('/'). See draft-klass.txt of the design docs
1237 * for more details and common types. E.g: "Sink/File"
1238 * @description: Sentence describing the purpose of the element.
1239 * E.g: "Write stream to a file"
1240 * @author: Name and contact details of the author(s). Use \n to separate
1241 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1243 * Sets the detailed information for a #GstElementClass.
1244 * <note>This function is for use in _class_init functions only.</note>
1247 gst_element_class_set_metadata (GstElementClass * klass,
1248 const gchar * longname, const gchar * classification,
1249 const gchar * description, const gchar * author)
1251 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1253 gst_structure_set ((GstStructure *) klass->metadata,
1254 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1255 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1256 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1257 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1261 * gst_element_class_get_metadata:
1262 * @klass: class to get metadata for
1263 * @key: the key to get
1265 * Get metadata with @key in @klass.
1267 * Returns: the metadata for @key.
1270 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1272 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1273 g_return_val_if_fail (key != NULL, NULL);
1275 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1279 * gst_element_class_get_pad_template_list:
1280 * @element_class: a #GstElementClass to get pad templates of.
1282 * Retrieves a list of the pad templates associated with @element_class. The
1283 * list must not be modified by the calling code.
1284 * <note>If you use this function in the #GInstanceInitFunc of an object class
1285 * that has subclasses, make sure to pass the g_class parameter of the
1286 * #GInstanceInitFunc here.</note>
1288 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1292 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1294 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1296 return element_class->padtemplates;
1300 * gst_element_class_get_pad_template:
1301 * @element_class: a #GstElementClass to get the pad template of.
1302 * @name: the name of the #GstPadTemplate to get.
1304 * Retrieves a padtemplate from @element_class with the given name.
1305 * <note>If you use this function in the #GInstanceInitFunc of an object class
1306 * that has subclasses, make sure to pass the g_class parameter of the
1307 * #GInstanceInitFunc here.</note>
1309 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1310 * if none was found. No unreferencing is necessary.
1313 gst_element_class_get_pad_template (GstElementClass *
1314 element_class, const gchar * name)
1318 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1319 g_return_val_if_fail (name != NULL, NULL);
1321 padlist = element_class->padtemplates;
1324 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1326 if (strcmp (padtempl->name_template, name) == 0)
1329 padlist = g_list_next (padlist);
1335 static GstPadTemplate *
1336 gst_element_class_get_request_pad_template (GstElementClass *
1337 element_class, const gchar * name)
1339 GstPadTemplate *tmpl;
1341 tmpl = gst_element_class_get_pad_template (element_class, name);
1342 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1348 /* get a random pad on element of the given direction.
1349 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1352 gst_element_get_random_pad (GstElement * element,
1353 gboolean need_linked, GstPadDirection dir)
1355 GstPad *result = NULL;
1358 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1362 GST_OBJECT_LOCK (element);
1363 pads = element->srcpads;
1366 GST_OBJECT_LOCK (element);
1367 pads = element->sinkpads;
1370 goto wrong_direction;
1372 for (; pads; pads = g_list_next (pads)) {
1373 GstPad *pad = GST_PAD_CAST (pads->data);
1375 GST_OBJECT_LOCK (pad);
1376 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1377 GST_DEBUG_PAD_NAME (pad));
1379 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1380 /* if we require a linked pad, and it is not linked, continue the
1382 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1383 GST_DEBUG_PAD_NAME (pad));
1384 GST_OBJECT_UNLOCK (pad);
1387 /* found a pad, stop search */
1388 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1389 GST_DEBUG_PAD_NAME (pad));
1390 GST_OBJECT_UNLOCK (pad);
1396 gst_object_ref (result);
1398 GST_OBJECT_UNLOCK (element);
1402 /* ERROR handling */
1405 g_warning ("unknown pad direction %d", dir);
1411 gst_element_default_send_event (GstElement * element, GstEvent * event)
1413 gboolean result = FALSE;
1416 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1417 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1418 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1421 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1422 "pushing %s event to random %s pad %s:%s",
1423 GST_EVENT_TYPE_NAME (event),
1424 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1425 GST_DEBUG_PAD_NAME (pad));
1427 result = gst_pad_push_event (pad, event);
1428 gst_object_unref (pad);
1430 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1431 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1432 gst_event_unref (event);
1438 * gst_element_send_event:
1439 * @element: a #GstElement to send the event to.
1440 * @event: (transfer full): the #GstEvent to send to the element.
1442 * Sends an event to an element. If the element doesn't implement an
1443 * event handler, the event will be pushed on a random linked sink pad for
1444 * upstream events or a random linked source pad for downstream events.
1446 * This function takes owership of the provided event so you should
1447 * gst_event_ref() it if you want to reuse the event after this call.
1449 * Returns: %TRUE if the event was handled.
1454 gst_element_send_event (GstElement * element, GstEvent * event)
1456 GstElementClass *oclass;
1457 gboolean result = FALSE;
1459 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1460 g_return_val_if_fail (event != NULL, FALSE);
1462 oclass = GST_ELEMENT_GET_CLASS (element);
1464 GST_STATE_LOCK (element);
1465 if (oclass->send_event) {
1466 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1467 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1468 result = oclass->send_event (element, event);
1470 GST_STATE_UNLOCK (element);
1477 * @element: a #GstElement to send the event to.
1478 * @rate: The new playback rate
1479 * @format: The format of the seek values
1480 * @flags: The optional seek flags.
1481 * @cur_type: The type and flags for the new current position
1482 * @cur: The value of the new current position
1483 * @stop_type: The type and flags for the new stop position
1484 * @stop: The value of the new stop position
1486 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1487 * the parameters. The seek event is sent to the element using
1488 * gst_element_send_event().
1490 * Returns: %TRUE if the event was handled.
1495 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1496 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1497 GstSeekType stop_type, gint64 stop)
1502 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1505 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1506 result = gst_element_send_event (element, event);
1512 gst_element_default_query (GstElement * element, GstQuery * query)
1514 gboolean result = FALSE;
1517 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1519 result = gst_pad_query (pad, query);
1521 gst_object_unref (pad);
1523 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1525 GstPad *peer = gst_pad_get_peer (pad);
1528 result = gst_pad_query (peer, query);
1530 gst_object_unref (peer);
1532 gst_object_unref (pad);
1539 * gst_element_query:
1540 * @element: a #GstElement to perform the query on.
1541 * @query: (transfer none): the #GstQuery.
1543 * Performs a query on the given element.
1545 * For elements that don't implement a query handler, this function
1546 * forwards the query to a random srcpad or to the peer of a
1547 * random linked sinkpad of this element.
1549 * Please note that some queries might need a running pipeline to work.
1551 * Returns: TRUE if the query could be performed.
1556 gst_element_query (GstElement * element, GstQuery * query)
1558 GstElementClass *oclass;
1559 gboolean result = FALSE;
1561 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1562 g_return_val_if_fail (query != NULL, FALSE);
1564 oclass = GST_ELEMENT_GET_CLASS (element);
1566 if (oclass->query) {
1567 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1568 GST_ELEMENT_NAME (element));
1569 result = oclass->query (element, query);
1575 * gst_element_post_message:
1576 * @element: a #GstElement posting the message
1577 * @message: (transfer full): a #GstMessage to post
1579 * Post a message on the element's #GstBus. This function takes ownership of the
1580 * message; if you want to access the message after this call, you should add an
1581 * additional reference before calling.
1583 * Returns: %TRUE if the message was successfully posted. The function returns
1584 * %FALSE if the element did not have a bus.
1589 gst_element_post_message (GstElement * element, GstMessage * message)
1592 gboolean result = FALSE;
1594 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1595 g_return_val_if_fail (message != NULL, FALSE);
1597 GST_OBJECT_LOCK (element);
1600 if (G_UNLIKELY (bus == NULL))
1603 gst_object_ref (bus);
1604 GST_OBJECT_UNLOCK (element);
1606 /* we release the element lock when posting the message so that any
1607 * (synchronous) message handlers can operate on the element */
1608 result = gst_bus_post (bus, message);
1609 gst_object_unref (bus);
1616 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1617 "not posting message %p: no bus", message);
1618 GST_OBJECT_UNLOCK (element);
1619 gst_message_unref (message);
1625 * _gst_element_error_printf:
1626 * @format: the printf-like format to use, or %NULL
1628 * This function is only used internally by the gst_element_error() macro.
1630 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1636 _gst_element_error_printf (const gchar * format, ...)
1646 va_start (args, format);
1647 buffer = g_strdup_vprintf (format, args);
1653 * gst_element_message_full:
1654 * @element: a #GstElement to send message from
1655 * @type: the #GstMessageType
1656 * @domain: the GStreamer GError domain this message belongs to
1657 * @code: the GError code belonging to the domain
1658 * @text: (allow-none) (transfer full): an allocated text string to be used
1659 * as a replacement for the default message connected to code,
1661 * @debug: (allow-none) (transfer full): an allocated debug message to be
1662 * used as a replacement for the default debugging information,
1664 * @file: the source code file where the error was generated
1665 * @function: the source code function where the error was generated
1666 * @line: the source code line where the error was generated
1668 * Post an error, warning or info message on the bus from inside an element.
1670 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1671 * #GST_MESSAGE_INFO.
1675 void gst_element_message_full
1676 (GstElement * element, GstMessageType type,
1677 GQuark domain, gint code, gchar * text,
1678 gchar * debug, const gchar * file, const gchar * function, gint line)
1680 GError *gerror = NULL;
1684 gboolean has_debug = TRUE;
1685 GstMessage *message = NULL;
1688 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1689 g_return_if_fail (GST_IS_ELEMENT (element));
1690 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1691 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1693 /* check if we send the given text or the default error text */
1694 if ((text == NULL) || (text[0] == 0)) {
1695 /* text could have come from g_strdup_printf (""); */
1697 sent_text = gst_error_get_message (domain, code);
1701 /* construct a sent_debug with extra information from source */
1702 if ((debug == NULL) || (debug[0] == 0)) {
1703 /* debug could have come from g_strdup_printf (""); */
1707 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1709 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1710 file, line, function, name, debug);
1712 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1713 file, line, function, name);
1717 /* create gerror and post message */
1718 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1720 gerror = g_error_new_literal (domain, code, sent_text);
1723 case GST_MESSAGE_ERROR:
1725 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1727 case GST_MESSAGE_WARNING:
1728 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1731 case GST_MESSAGE_INFO:
1732 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1736 g_assert_not_reached ();
1739 gst_element_post_message (element, message);
1741 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1742 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1745 g_error_free (gerror);
1746 g_free (sent_debug);
1751 * gst_element_is_locked_state:
1752 * @element: a #GstElement.
1754 * Checks if the state of an element is locked.
1755 * If the state of an element is locked, state changes of the parent don't
1756 * affect the element.
1757 * This way you can leave currently unused elements inside bins. Just lock their
1758 * state before changing the state from #GST_STATE_NULL.
1762 * Returns: TRUE, if the element's state is locked.
1765 gst_element_is_locked_state (GstElement * element)
1769 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1771 GST_OBJECT_LOCK (element);
1772 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1773 GST_OBJECT_UNLOCK (element);
1779 * gst_element_set_locked_state:
1780 * @element: a #GstElement
1781 * @locked_state: TRUE to lock the element's state
1783 * Locks the state of an element, so state changes of the parent don't affect
1784 * this element anymore.
1788 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1789 * or the elements state-locking needed no change.
1792 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1796 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1798 GST_OBJECT_LOCK (element);
1799 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1801 if (G_UNLIKELY (old == locked_state))
1805 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1806 GST_ELEMENT_NAME (element));
1807 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1809 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1810 GST_ELEMENT_NAME (element));
1811 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1813 GST_OBJECT_UNLOCK (element);
1819 GST_CAT_DEBUG (GST_CAT_STATES,
1820 "elements %s was already in locked state %d",
1821 GST_ELEMENT_NAME (element), old);
1822 GST_OBJECT_UNLOCK (element);
1829 * gst_element_sync_state_with_parent:
1830 * @element: a #GstElement.
1832 * Tries to change the state of the element to the same as its parent.
1833 * If this function returns FALSE, the state of element is undefined.
1835 * Returns: TRUE, if the element's state could be synced to the parent's state.
1840 gst_element_sync_state_with_parent (GstElement * element)
1844 GstStateChangeReturn ret;
1846 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1848 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1849 GstState parent_current, parent_pending;
1851 GST_OBJECT_LOCK (parent);
1852 parent_current = GST_STATE (parent);
1853 parent_pending = GST_STATE_PENDING (parent);
1854 GST_OBJECT_UNLOCK (parent);
1856 /* set to pending if there is one, else we set it to the current state of
1858 if (parent_pending != GST_STATE_VOID_PENDING)
1859 target = parent_pending;
1861 target = parent_current;
1863 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1864 "syncing state (%s) to parent %s %s (%s, %s)",
1865 gst_element_state_get_name (GST_STATE (element)),
1866 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1867 gst_element_state_get_name (parent_current),
1868 gst_element_state_get_name (parent_pending));
1870 ret = gst_element_set_state (element, target);
1871 if (ret == GST_STATE_CHANGE_FAILURE)
1874 gst_object_unref (parent);
1878 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1885 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1886 "syncing state failed (%s)",
1887 gst_element_state_change_return_get_name (ret));
1888 gst_object_unref (parent);
1894 static GstStateChangeReturn
1895 gst_element_get_state_func (GstElement * element,
1896 GstState * state, GstState * pending, GstClockTime timeout)
1898 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1899 GstState old_pending;
1901 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1902 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1904 GST_OBJECT_LOCK (element);
1905 ret = GST_STATE_RETURN (element);
1906 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1907 gst_element_state_change_return_get_name (ret));
1909 /* we got an error, report immediately */
1910 if (ret == GST_STATE_CHANGE_FAILURE)
1913 /* we got no_preroll, report immediately */
1914 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1917 /* no need to wait async if we are not async */
1918 if (ret != GST_STATE_CHANGE_ASYNC)
1921 old_pending = GST_STATE_PENDING (element);
1922 if (old_pending != GST_STATE_VOID_PENDING) {
1923 GTimeVal *timeval, abstimeout;
1926 if (timeout != GST_CLOCK_TIME_NONE) {
1927 glong add = timeout / 1000;
1932 /* make timeout absolute */
1933 g_get_current_time (&abstimeout);
1934 g_time_val_add (&abstimeout, add);
1935 timeval = &abstimeout;
1939 /* get cookie to detect state changes during waiting */
1940 cookie = element->state_cookie;
1942 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1943 "waiting for element to commit state");
1945 /* we have a pending state change, wait for it to complete */
1946 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1947 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1948 /* timeout triggered */
1949 ret = GST_STATE_CHANGE_ASYNC;
1951 if (cookie != element->state_cookie)
1954 /* could be success or failure */
1955 if (old_pending == GST_STATE (element)) {
1956 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1957 ret = GST_STATE_CHANGE_SUCCESS;
1959 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1960 ret = GST_STATE_CHANGE_FAILURE;
1963 /* if nothing is pending anymore we can return SUCCESS */
1964 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1965 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1966 ret = GST_STATE_CHANGE_SUCCESS;
1972 *state = GST_STATE (element);
1974 *pending = GST_STATE_PENDING (element);
1976 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1977 "state current: %s, pending: %s, result: %s",
1978 gst_element_state_get_name (GST_STATE (element)),
1979 gst_element_state_get_name (GST_STATE_PENDING (element)),
1980 gst_element_state_change_return_get_name (ret));
1981 GST_OBJECT_UNLOCK (element);
1988 *state = GST_STATE_VOID_PENDING;
1990 *pending = GST_STATE_VOID_PENDING;
1992 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
1994 GST_OBJECT_UNLOCK (element);
1996 return GST_STATE_CHANGE_FAILURE;
2001 * gst_element_get_state:
2002 * @element: a #GstElement to get the state of.
2003 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2005 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2006 * state. Can be %NULL.
2007 * @timeout: a #GstClockTime to specify the timeout for an async
2008 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2010 * Gets the state of the element.
2012 * For elements that performed an ASYNC state change, as reported by
2013 * gst_element_set_state(), this function will block up to the
2014 * specified timeout value for the state change to complete.
2015 * If the element completes the state change or goes into
2016 * an error, this function returns immediately with a return value of
2017 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2019 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2020 * returns the current and pending state immediately.
2022 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2023 * successfully changed its state but is not able to provide data yet.
2024 * This mostly happens for live sources that only produce data in
2025 * %GST_STATE_PLAYING. While the state change return is equivalent to
2026 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2027 * some sink elements might not be able to complete their state change because
2028 * an element is not producing data to complete the preroll. When setting the
2029 * element to playing, the preroll will complete and playback will start.
2031 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2032 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2033 * element is still performing a state change or
2034 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2038 GstStateChangeReturn
2039 gst_element_get_state (GstElement * element,
2040 GstState * state, GstState * pending, GstClockTime timeout)
2042 GstElementClass *oclass;
2043 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2045 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2047 oclass = GST_ELEMENT_GET_CLASS (element);
2049 if (oclass->get_state)
2050 result = (oclass->get_state) (element, state, pending, timeout);
2056 * gst_element_abort_state:
2057 * @element: a #GstElement to abort the state of.
2059 * Abort the state change of the element. This function is used
2060 * by elements that do asynchronous state changes and find out
2061 * something is wrong.
2063 * This function should be called with the STATE_LOCK held.
2068 gst_element_abort_state (GstElement * element)
2072 #ifndef GST_DISABLE_GST_DEBUG
2076 g_return_if_fail (GST_IS_ELEMENT (element));
2078 GST_OBJECT_LOCK (element);
2079 pending = GST_STATE_PENDING (element);
2081 if (pending == GST_STATE_VOID_PENDING ||
2082 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2083 goto nothing_aborted;
2085 #ifndef GST_DISABLE_GST_DEBUG
2086 old_state = GST_STATE (element);
2088 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2089 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2090 gst_element_state_get_name (pending));
2094 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2096 GST_STATE_BROADCAST (element);
2097 GST_OBJECT_UNLOCK (element);
2103 GST_OBJECT_UNLOCK (element);
2108 /* Not static because GstBin has manual state handling too */
2110 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2111 GstState newstate, GstState pending)
2113 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2114 GstMessage *message;
2116 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2117 "notifying about state-changed %s to %s (%s pending)",
2118 gst_element_state_get_name (oldstate),
2119 gst_element_state_get_name (newstate),
2120 gst_element_state_get_name (pending));
2122 if (klass->state_changed)
2123 klass->state_changed (element, oldstate, newstate, pending);
2125 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2126 oldstate, newstate, pending);
2127 gst_element_post_message (element, message);
2131 * gst_element_continue_state:
2132 * @element: a #GstElement to continue the state change of.
2133 * @ret: The previous state return value
2135 * Commit the state change of the element and proceed to the next
2136 * pending state if any. This function is used
2137 * by elements that do asynchronous state changes.
2138 * The core will normally call this method automatically when an
2139 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2141 * If after calling this method the element still has not reached
2142 * the pending state, the next state change is performed.
2144 * This method is used internally and should normally not be called by plugins
2147 * Returns: The result of the commit state change.
2151 GstStateChangeReturn
2152 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2154 GstStateChangeReturn old_ret;
2155 GstState old_state, old_next;
2156 GstState current, next, pending;
2157 GstStateChange transition;
2159 GST_OBJECT_LOCK (element);
2160 old_ret = GST_STATE_RETURN (element);
2161 GST_STATE_RETURN (element) = ret;
2162 pending = GST_STATE_PENDING (element);
2164 /* check if there is something to commit */
2165 if (pending == GST_STATE_VOID_PENDING)
2166 goto nothing_pending;
2168 old_state = GST_STATE (element);
2169 /* this is the state we should go to next */
2170 old_next = GST_STATE_NEXT (element);
2171 /* update current state */
2172 current = GST_STATE (element) = old_next;
2174 /* see if we reached the final state */
2175 if (pending == current)
2178 next = GST_STATE_GET_NEXT (current, pending);
2179 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2181 GST_STATE_NEXT (element) = next;
2183 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2184 GST_OBJECT_UNLOCK (element);
2186 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2187 "committing state from %s to %s, pending %s, next %s",
2188 gst_element_state_get_name (old_state),
2189 gst_element_state_get_name (old_next),
2190 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2192 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2194 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2195 "continue state change %s to %s, final %s",
2196 gst_element_state_get_name (current),
2197 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2199 ret = gst_element_change_state (element, transition);
2205 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2206 GST_OBJECT_UNLOCK (element);
2211 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2212 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2214 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2215 "completed state change to %s", gst_element_state_get_name (pending));
2216 GST_OBJECT_UNLOCK (element);
2218 /* don't post silly messages with the same state. This can happen
2219 * when an element state is changed to what it already was. For bins
2220 * this can be the result of a lost state, which we check with the
2221 * previous return value.
2222 * We do signal the cond though as a _get_state() might be blocking
2224 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2225 _priv_gst_element_state_changed (element, old_state, old_next,
2226 GST_STATE_VOID_PENDING);
2228 GST_STATE_BROADCAST (element);
2235 * gst_element_lost_state:
2236 * @element: a #GstElement the state is lost of
2238 * Brings the element to the lost state. The current state of the
2239 * element is copied to the pending state so that any call to
2240 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2242 * An ASYNC_START message is posted. If the element was PLAYING, it will
2243 * go to PAUSED. The element will be restored to its PLAYING state by
2244 * the parent pipeline when it prerolls again.
2246 * This is mostly used for elements that lost their preroll buffer
2247 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2248 * they will go to their pending state again when a new preroll buffer is
2249 * queued. This function can only be called when the element is currently
2250 * not in error or an async state change.
2252 * This function is used internally and should normally not be called from
2253 * plugins or applications.
2256 gst_element_lost_state (GstElement * element)
2258 GstState old_state, new_state;
2259 GstMessage *message;
2261 g_return_if_fail (GST_IS_ELEMENT (element));
2263 GST_OBJECT_LOCK (element);
2264 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2267 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2268 goto only_async_start;
2270 old_state = GST_STATE (element);
2272 /* when we were PLAYING, the new state is PAUSED. We will also not
2273 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2274 * when we preroll. */
2275 if (old_state > GST_STATE_PAUSED)
2276 new_state = GST_STATE_PAUSED;
2278 new_state = old_state;
2280 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2281 "lost state of %s to %s", gst_element_state_get_name (old_state),
2282 gst_element_state_get_name (new_state));
2284 GST_STATE (element) = new_state;
2285 GST_STATE_NEXT (element) = new_state;
2286 GST_STATE_PENDING (element) = new_state;
2287 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2288 GST_OBJECT_UNLOCK (element);
2290 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2292 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2293 gst_element_post_message (element, message);
2299 GST_OBJECT_UNLOCK (element);
2304 GST_OBJECT_UNLOCK (element);
2306 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2307 gst_element_post_message (element, message);
2313 * gst_element_set_state:
2314 * @element: a #GstElement to change state of.
2315 * @state: the element's new #GstState.
2317 * Sets the state of the element. This function will try to set the
2318 * requested state by going through all the intermediary states and calling
2319 * the class's state change function for each.
2321 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2322 * element will perform the remainder of the state change asynchronously in
2324 * An application can use gst_element_get_state() to wait for the completion
2325 * of the state change or it can wait for a state change message on the bus.
2327 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2328 * #GST_STATE_CHANGE_ASYNC.
2330 * Returns: Result of the state change using #GstStateChangeReturn.
2334 GstStateChangeReturn
2335 gst_element_set_state (GstElement * element, GstState state)
2337 GstElementClass *oclass;
2338 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2340 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2342 oclass = GST_ELEMENT_GET_CLASS (element);
2344 if (oclass->set_state)
2345 result = (oclass->set_state) (element, state);
2351 * default set state function, calculates the next state based
2352 * on current state and calls the change_state function
2354 static GstStateChangeReturn
2355 gst_element_set_state_func (GstElement * element, GstState state)
2357 GstState current, next, old_pending;
2358 GstStateChangeReturn ret;
2359 GstStateChange transition;
2360 GstStateChangeReturn old_ret;
2362 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2364 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2365 gst_element_state_get_name (state));
2367 /* state lock is taken to protect the set_state() and get_state()
2368 * procedures, it does not lock any variables. */
2369 GST_STATE_LOCK (element);
2371 /* now calculate how to get to the new state */
2372 GST_OBJECT_LOCK (element);
2373 old_ret = GST_STATE_RETURN (element);
2374 /* previous state change returned an error, remove all pending
2375 * and next states */
2376 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2377 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2378 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2379 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2382 current = GST_STATE (element);
2383 next = GST_STATE_NEXT (element);
2384 old_pending = GST_STATE_PENDING (element);
2386 /* this is the (new) state we should go to. TARGET is the last state we set on
2388 if (state != GST_STATE_TARGET (element)) {
2389 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2390 "setting target state to %s", gst_element_state_get_name (state));
2391 GST_STATE_TARGET (element) = state;
2392 /* increment state cookie so that we can track each state change. We only do
2393 * this if this is actually a new state change. */
2394 element->state_cookie++;
2396 GST_STATE_PENDING (element) = state;
2398 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2399 "current %s, old_pending %s, next %s, old return %s",
2400 gst_element_state_get_name (current),
2401 gst_element_state_get_name (old_pending),
2402 gst_element_state_get_name (next),
2403 gst_element_state_change_return_get_name (old_ret));
2405 /* if the element was busy doing a state change, we just update the
2406 * target state, it'll get to it async then. */
2407 if (old_pending != GST_STATE_VOID_PENDING) {
2408 /* upwards state change will happen ASYNC */
2409 if (old_pending <= state)
2411 /* element is going to this state already */
2412 else if (next == state)
2414 /* element was performing an ASYNC upward state change and
2415 * we request to go downward again. Start from the next pending
2417 else if (next > state
2418 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2422 next = GST_STATE_GET_NEXT (current, state);
2423 /* now we store the next state */
2424 GST_STATE_NEXT (element) = next;
2425 /* mark busy, we need to check that there is actually a state change
2426 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2427 * the default element change_state function has no way to know what the
2428 * old value was... could consider this a FIXME...*/
2429 if (current != next)
2430 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2432 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2434 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2435 "%s: setting state from %s to %s",
2436 (next != state ? "intermediate" : "final"),
2437 gst_element_state_get_name (current), gst_element_state_get_name (next));
2439 /* now signal any waiters, they will error since the cookie was incremented */
2440 GST_STATE_BROADCAST (element);
2442 GST_OBJECT_UNLOCK (element);
2444 ret = gst_element_change_state (element, transition);
2446 GST_STATE_UNLOCK (element);
2448 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2449 gst_element_state_change_return_get_name (ret));
2455 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2456 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2457 "element was busy with async state change");
2458 GST_OBJECT_UNLOCK (element);
2460 GST_STATE_UNLOCK (element);
2462 return GST_STATE_CHANGE_ASYNC;
2467 * gst_element_change_state:
2468 * @element: a #GstElement
2469 * @transition: the requested transition
2471 * Perform @transition on @element.
2473 * This function must be called with STATE_LOCK held and is mainly used
2476 * Returns: the #GstStateChangeReturn of the state transition.
2478 GstStateChangeReturn
2479 gst_element_change_state (GstElement * element, GstStateChange transition)
2481 GstElementClass *oclass;
2482 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2484 oclass = GST_ELEMENT_GET_CLASS (element);
2486 /* call the state change function so it can set the state */
2487 if (oclass->change_state)
2488 ret = (oclass->change_state) (element, transition);
2490 ret = GST_STATE_CHANGE_FAILURE;
2493 case GST_STATE_CHANGE_FAILURE:
2494 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2495 "have FAILURE change_state return");
2496 /* state change failure */
2497 gst_element_abort_state (element);
2499 case GST_STATE_CHANGE_ASYNC:
2503 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2504 "element will change state ASYNC");
2506 target = GST_STATE_TARGET (element);
2508 if (target > GST_STATE_READY)
2511 /* else we just continue the state change downwards */
2512 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2513 "forcing commit state %s <= %s",
2514 gst_element_state_get_name (target),
2515 gst_element_state_get_name (GST_STATE_READY));
2517 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2520 case GST_STATE_CHANGE_SUCCESS:
2521 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2522 "element changed state SUCCESS");
2523 /* we can commit the state now which will proceeed to
2525 ret = gst_element_continue_state (element, ret);
2527 case GST_STATE_CHANGE_NO_PREROLL:
2528 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2529 "element changed state NO_PREROLL");
2530 /* we can commit the state now which will proceeed to
2532 ret = gst_element_continue_state (element, ret);
2535 goto invalid_return;
2538 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2543 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2551 GST_OBJECT_LOCK (element);
2552 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2553 g_critical ("%s: unknown return value %d from a state change function",
2554 GST_ELEMENT_NAME (element), ret);
2556 /* we are in error now */
2557 ret = GST_STATE_CHANGE_FAILURE;
2558 GST_STATE_RETURN (element) = ret;
2559 GST_OBJECT_UNLOCK (element);
2565 /* gst_iterator_fold functions for pads_activate
2566 * Stop the iterator if activating one pad failed. */
2568 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2570 GstPad *pad = g_value_get_object (vpad);
2571 gboolean cont = TRUE;
2573 if (!(cont = gst_pad_set_active (pad, *active)))
2574 g_value_set_boolean (ret, FALSE);
2579 /* returns false on error or early cutout of the fold, true if all
2580 * pads in @iter were (de)activated successfully. */
2582 iterator_activate_fold_with_resync (GstIterator * iter,
2583 GstIteratorFoldFunction func, gpointer user_data)
2585 GstIteratorResult ires;
2588 /* no need to unset this later, it's just a boolean */
2589 g_value_init (&ret, G_TYPE_BOOLEAN);
2590 g_value_set_boolean (&ret, TRUE);
2593 ires = gst_iterator_fold (iter, func, &ret, user_data);
2595 case GST_ITERATOR_RESYNC:
2596 /* need to reset the result again */
2597 g_value_set_boolean (&ret, TRUE);
2598 gst_iterator_resync (iter);
2600 case GST_ITERATOR_DONE:
2601 /* all pads iterated, return collected value */
2604 /* iterator returned _ERROR or premature end with _OK,
2605 * mark an error and exit */
2606 g_value_set_boolean (&ret, FALSE);
2611 /* return collected value */
2612 return g_value_get_boolean (&ret);
2615 /* is called with STATE_LOCK
2617 * Pads are activated from source pads to sinkpads.
2620 gst_element_pads_activate (GstElement * element, gboolean active)
2625 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2626 "pads_activate with active %d", active);
2628 iter = gst_element_iterate_src_pads (element);
2630 iterator_activate_fold_with_resync (iter,
2631 (GstIteratorFoldFunction) activate_pads, &active);
2632 gst_iterator_free (iter);
2633 if (G_UNLIKELY (!res))
2636 iter = gst_element_iterate_sink_pads (element);
2638 iterator_activate_fold_with_resync (iter,
2639 (GstIteratorFoldFunction) activate_pads, &active);
2640 gst_iterator_free (iter);
2641 if (G_UNLIKELY (!res))
2644 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2645 "pads_activate successful");
2652 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2653 "source pads_activate failed");
2658 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2659 "sink pads_activate failed");
2664 /* is called with STATE_LOCK */
2665 static GstStateChangeReturn
2666 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2668 GstState state, next;
2669 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2671 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2673 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2674 next = GST_STATE_TRANSITION_NEXT (transition);
2676 /* if the element already is in the given state, we just return success */
2677 if (next == GST_STATE_VOID_PENDING || state == next)
2680 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2681 "default handler tries setting state from %s to %s (%04x)",
2682 gst_element_state_get_name (state),
2683 gst_element_state_get_name (next), transition);
2685 switch (transition) {
2686 case GST_STATE_CHANGE_NULL_TO_READY:
2688 case GST_STATE_CHANGE_READY_TO_PAUSED:
2689 if (!gst_element_pads_activate (element, TRUE)) {
2690 result = GST_STATE_CHANGE_FAILURE;
2693 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2695 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2697 case GST_STATE_CHANGE_PAUSED_TO_READY:
2698 case GST_STATE_CHANGE_READY_TO_NULL:
2699 /* deactivate pads in both cases, since they are activated on
2700 ready->paused but the element might not have made it to paused */
2701 if (!gst_element_pads_activate (element, FALSE)) {
2702 result = GST_STATE_CHANGE_FAILURE;
2706 /* this will catch real but unhandled state changes;
2707 * can only be caused by:
2708 * - a new state was added
2709 * - somehow the element was asked to jump across an intermediate state
2711 g_warning ("Unhandled state change from %s to %s",
2712 gst_element_state_get_name (state),
2713 gst_element_state_get_name (next));
2720 GST_OBJECT_LOCK (element);
2721 result = GST_STATE_RETURN (element);
2722 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2723 "element is already in the %s state",
2724 gst_element_state_get_name (state));
2725 GST_OBJECT_UNLOCK (element);
2732 * gst_element_get_factory:
2733 * @element: a #GstElement to request the element factory of.
2735 * Retrieves the factory that was used to create this element.
2737 * Returns: (transfer none): the #GstElementFactory used for creating this
2738 * element. no refcounting is needed.
2741 gst_element_get_factory (GstElement * element)
2743 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2745 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2749 gst_element_dispose (GObject * object)
2751 GstElement *element = GST_ELEMENT_CAST (object);
2755 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2757 if (GST_STATE (element) != GST_STATE_NULL)
2760 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2761 "removing %d pads", g_list_length (element->pads));
2762 /* first we break all our links with the outside */
2763 while (element->pads && element->pads->data) {
2764 /* don't call _remove_pad with NULL */
2765 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2767 if (G_UNLIKELY (element->pads != NULL)) {
2768 g_critical ("could not remove pads from element %s",
2769 GST_STR_NULL (GST_OBJECT_NAME (object)));
2772 GST_OBJECT_LOCK (element);
2773 clock_p = &element->clock;
2774 bus_p = &element->bus;
2775 gst_object_replace ((GstObject **) clock_p, NULL);
2776 gst_object_replace ((GstObject **) bus_p, NULL);
2777 GST_OBJECT_UNLOCK (element);
2779 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2781 G_OBJECT_CLASS (parent_class)->dispose (object);
2790 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2792 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2794 "You need to explicitly set elements to the NULL state before\n"
2795 "dropping the final reference, to allow them to clean up.\n"
2796 "This problem may also be caused by a refcounting bug in the\n"
2797 "application or some element.\n",
2798 GST_OBJECT_NAME (element),
2799 gst_element_state_get_name (GST_STATE (element)),
2800 is_locked ? " (locked)" : "");
2806 gst_element_finalize (GObject * object)
2808 GstElement *element = GST_ELEMENT_CAST (object);
2810 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2812 g_cond_free (element->state_cond);
2813 g_static_rec_mutex_free (&element->state_lock);
2815 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2817 G_OBJECT_CLASS (parent_class)->finalize (object);
2821 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2825 g_return_if_fail (GST_IS_ELEMENT (element));
2827 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2829 GST_OBJECT_LOCK (element);
2830 bus_p = &GST_ELEMENT_BUS (element);
2831 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2832 GST_OBJECT_UNLOCK (element);
2836 * gst_element_set_bus:
2837 * @element: a #GstElement to set the bus of.
2838 * @bus: (transfer none): the #GstBus to set.
2840 * Sets the bus of the element. Increases the refcount on the bus.
2841 * For internal use only, unless you're testing elements.
2846 gst_element_set_bus (GstElement * element, GstBus * bus)
2848 GstElementClass *oclass;
2850 g_return_if_fail (GST_IS_ELEMENT (element));
2852 oclass = GST_ELEMENT_GET_CLASS (element);
2854 if (oclass->set_bus)
2855 oclass->set_bus (element, bus);
2859 * gst_element_get_bus:
2860 * @element: a #GstElement to get the bus of.
2862 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2863 * bus for the application.
2865 * Returns: (transfer full): the element's #GstBus. unref after usage.
2870 gst_element_get_bus (GstElement * element)
2872 GstBus *result = NULL;
2874 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2876 GST_OBJECT_LOCK (element);
2877 if ((result = GST_ELEMENT_BUS (element)))
2878 gst_object_ref (result);
2879 GST_OBJECT_UNLOCK (element);
2881 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,