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 * A pad of an element can be retrieved by name with gst_element_get_pad().
45 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
47 * Elements can be linked through their pads.
48 * If the link is straightforward, use the gst_element_link()
49 * convenience function to link two elements, or gst_element_link_many()
50 * for more elements in a row.
51 * Use gst_element_link_filtered() to link two elements constrained by
52 * a specified set of #GstCaps.
53 * For finer control, use gst_element_link_pads() and
54 * gst_element_link_pads_filtered() to specify the pads to link on
55 * each element by name.
57 * Each element has a state (see #GstState). You can get and set the state
58 * of an element with gst_element_get_state() and gst_element_set_state().
59 * To get a string representation of a #GstState, use
60 * gst_element_state_get_name().
62 * You can get and set a #GstClock on an element using gst_element_get_clock()
63 * and gst_element_set_clock().
64 * Some elements can provide a clock for the pipeline if
65 * gst_element_provides_clock() returns %TRUE. With the
66 * gst_element_provide_clock() method one can retrieve the clock provided by
68 * Not all elements require a clock to operate correctly. If
69 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
70 * element with gst_element_set_clock().
72 * Note that clock slection and distribution is normally handled by the
73 * toplevel #GstPipeline so the clock functions are only to be used in very
74 * specific situations.
76 * Last reviewed on 2009-05-29 (0.10.24)
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
85 #include "gstenumtypes.h"
87 #include "gstmarshal.h"
93 #include "gst-i18n-lib.h"
95 /* Element signals and args */
111 extern void __gst_element_details_clear (GstElementDetails * dp);
112 extern void __gst_element_details_copy (GstElementDetails * dest,
113 const GstElementDetails * src);
115 static void gst_element_class_init (GstElementClass * klass);
116 static void gst_element_init (GstElement * element);
117 static void gst_element_base_class_init (gpointer g_class);
118 static void gst_element_base_class_finalize (gpointer g_class);
120 static void gst_element_dispose (GObject * object);
121 static void gst_element_finalize (GObject * object);
123 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
124 GstStateChange transition);
125 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
126 GstState * state, GstState * pending, GstClockTime timeout);
127 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
129 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
131 static gboolean gst_element_default_send_event (GstElement * element,
133 static gboolean gst_element_default_query (GstElement * element,
136 static GstPadTemplate
137 * gst_element_class_get_request_pad_template (GstElementClass *
138 element_class, const gchar * name);
140 #ifndef GST_DISABLE_LOADSAVE
141 static xmlNodePtr gst_element_save_thyself (GstObject * object,
143 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
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;
186 GstObjectClass *gstobject_class;
188 gobject_class = (GObjectClass *) klass;
189 gstobject_class = (GstObjectClass *) klass;
191 parent_class = g_type_class_peek_parent (klass);
194 * GstElement::pad-added:
195 * @gstelement: the object which received the signal
196 * @new_pad: the pad that has been added
198 * a new #GstPad has been added to the element.
200 gst_element_signals[PAD_ADDED] =
201 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
202 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
203 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
205 * GstElement::pad-removed:
206 * @gstelement: the object which received the signal
207 * @old_pad: the pad that has been removed
209 * a #GstPad has been removed from the element
211 gst_element_signals[PAD_REMOVED] =
212 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
213 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
214 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
216 * GstElement::no-more-pads:
217 * @gstelement: the object which received the signal
219 * This signals that the element will not generate more dynamic pads.
221 gst_element_signals[NO_MORE_PADS] =
222 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
223 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
224 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
226 gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_element_dispose);
227 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_finalize);
229 #ifndef GST_DISABLE_LOADSAVE
230 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
231 gstobject_class->restore_thyself =
232 GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
235 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
236 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
237 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
238 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
239 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
240 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
241 klass->numpadtemplates = 0;
243 klass->elementfactory = NULL;
247 gst_element_base_class_init (gpointer g_class)
249 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
251 /* FIXME 0.11: Copy the element details and instead of clearing the
252 * pad template list copy the list and increase the refcount of
253 * the pad templates by one.
255 * This will make it possible to add pad templates and set element
256 * details in the class_init functions and is the real GObject way
258 * See http://bugzilla.gnome.org/show_bug.cgi?id=491501
260 memset (&element_class->details, 0, sizeof (GstElementDetails));
261 element_class->padtemplates = NULL;
263 /* set the factory, see gst_element_register() */
264 element_class->elementfactory =
265 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
266 _gst_elementclass_factory);
267 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
268 element_class->elementfactory);
272 gst_element_base_class_finalize (gpointer g_class)
274 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
276 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
277 g_list_free (klass->padtemplates);
278 __gst_element_details_clear (&klass->details);
282 gst_element_init (GstElement * element)
284 GST_STATE (element) = GST_STATE_NULL;
285 GST_STATE_TARGET (element) = GST_STATE_NULL;
286 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
287 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
288 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
290 element->state_lock = g_new0 (GStaticRecMutex, 1);
291 g_static_rec_mutex_init (element->state_lock);
292 element->state_cond = g_cond_new ();
296 * gst_element_default_error:
297 * @object: a #GObject that signalled the error.
298 * @orig: the #GstObject that initiated the error.
299 * @error: the GError.
300 * @debug: an additional debug information string, or %NULL.
302 * A default error signal callback to attach to an element.
303 * The user data passed to the g_signal_connect is ignored.
305 * The default handler will simply print the error string using g_print.
310 gst_element_default_error (GObject * object, GstObject * source, GError * error,
313 gchar *name = gst_object_get_path_string (source);
315 g_print (_("ERROR: from element %s: %s\n"), name, error->message);
317 g_print (_("Additional debug info:\n%s\n"), debug);
323 * gst_element_release_request_pad:
324 * @element: a #GstElement to release the request pad of.
325 * @pad: the #GstPad to release.
327 * Makes the element free the previously requested pad as obtained
328 * with gst_element_get_request_pad().
330 * This does not unref the pad. If the pad was created by using
331 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
332 * followed by gst_object_unref() to free the @pad.
337 gst_element_release_request_pad (GstElement * element, GstPad * pad)
339 GstElementClass *oclass;
341 g_return_if_fail (GST_IS_ELEMENT (element));
342 g_return_if_fail (GST_IS_PAD (pad));
344 oclass = GST_ELEMENT_GET_CLASS (element);
346 /* if the element implements a custom release function we call that, else we
347 * simply remove the pad from the element */
348 if (oclass->release_pad)
349 (oclass->release_pad) (element, pad);
351 gst_element_remove_pad (element, pad);
355 * gst_element_requires_clock:
356 * @element: a #GstElement to query
358 * Query if the element requires a clock.
360 * Returns: %TRUE if the element requires a clock
365 gst_element_requires_clock (GstElement * element)
369 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
371 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
377 * gst_element_provides_clock:
378 * @element: a #GstElement to query
380 * Query if the element provides a clock. A #GstClock provided by an
381 * element can be used as the global #GstClock for the pipeline.
382 * An element that can provide a clock is only required to do so in the PAUSED
383 * state, this means when it is fully negotiated and has allocated the resources
384 * to operate the clock.
386 * Returns: %TRUE if the element provides a clock
391 gst_element_provides_clock (GstElement * element)
395 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
397 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
403 * gst_element_provide_clock:
404 * @element: a #GstElement to query
406 * Get the clock provided by the given element.
407 * <note>An element is only required to provide a clock in the PAUSED
408 * state. Some elements can provide a clock in other states.</note>
410 * Returns: the GstClock provided by the element or %NULL
411 * if no clock could be provided. Unref after usage.
416 gst_element_provide_clock (GstElement * element)
418 GstClock *result = NULL;
419 GstElementClass *oclass;
421 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
423 oclass = GST_ELEMENT_GET_CLASS (element);
425 if (oclass->provide_clock)
426 result = oclass->provide_clock (element);
432 * gst_element_set_clock:
433 * @element: a #GstElement to set the clock for.
434 * @clock: the #GstClock to set for the element.
436 * Sets the clock for the element. This function increases the
437 * refcount on the clock. Any previously set clock on the object
440 * Returns: %TRUE if the element accepted the clock. An element can refuse a
441 * clock when it, for example, is not able to slave its internal clock to the
442 * @clock or when it requires a specific clock to operate.
447 gst_element_set_clock (GstElement * element, GstClock * clock)
449 GstElementClass *oclass;
453 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
455 oclass = GST_ELEMENT_GET_CLASS (element);
457 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
459 if (oclass->set_clock)
460 res = oclass->set_clock (element, clock);
463 /* only update the clock pointer if the element accepted the clock */
464 GST_OBJECT_LOCK (element);
465 clock_p = &element->clock;
466 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
467 GST_OBJECT_UNLOCK (element);
473 * gst_element_get_clock:
474 * @element: a #GstElement to get the clock of.
476 * Gets the currently configured clock of the element. This is the clock as was
477 * last set with gst_element_set_clock().
479 * Returns: the #GstClock of the element. unref after usage.
484 gst_element_get_clock (GstElement * element)
488 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
490 GST_OBJECT_LOCK (element);
491 if ((result = element->clock))
492 gst_object_ref (result);
493 GST_OBJECT_UNLOCK (element);
499 * gst_element_set_base_time:
500 * @element: a #GstElement.
501 * @time: the base time to set.
503 * Set the base time of an element. See gst_element_get_base_time().
508 gst_element_set_base_time (GstElement * element, GstClockTime time)
512 g_return_if_fail (GST_IS_ELEMENT (element));
514 GST_OBJECT_LOCK (element);
515 old = element->base_time;
516 element->base_time = time;
517 GST_OBJECT_UNLOCK (element);
519 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
520 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
521 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
525 * gst_element_get_base_time:
526 * @element: a #GstElement.
528 * Returns the base time of the element. The base time is the
529 * absolute time of the clock when this element was last put to
530 * PLAYING. Subtracting the base time from the clock time gives
531 * the running time of the element.
533 * Returns: the base time of the element.
538 gst_element_get_base_time (GstElement * element)
542 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
544 GST_OBJECT_LOCK (element);
545 result = element->base_time;
546 GST_OBJECT_UNLOCK (element);
552 * gst_element_set_start_time:
553 * @element: a #GstElement.
554 * @time: the base time to set.
556 * Set the start time of an element. The start time of the element is the
557 * running time of the element when it last went to the PAUSED state. In READY
558 * or after a flushing seek, it is set to 0.
560 * Toplevel elements like #GstPipeline will manage the start_time and
561 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
562 * on such a toplevel element will disable the distribution of the base_time to
563 * the children and can be useful if the application manages the base_time
564 * itself, for example if you want to synchronize capture from multiple
565 * pipelines, and you can also ensure that the pipelines have the same clock.
572 gst_element_set_start_time (GstElement * element, GstClockTime time)
576 g_return_if_fail (GST_IS_ELEMENT (element));
578 GST_OBJECT_LOCK (element);
579 old = GST_ELEMENT_START_TIME (element);
580 GST_ELEMENT_START_TIME (element) = time;
581 GST_OBJECT_UNLOCK (element);
583 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
584 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
585 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
589 * gst_element_get_start_time:
590 * @element: a #GstElement.
592 * Returns the start time of the element. The start time is the
593 * running time of the clock when this element was last put to PAUSED.
595 * Usually the start_time is managed by a toplevel element such as
600 * Returns: the start time of the element.
605 gst_element_get_start_time (GstElement * element)
609 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
611 GST_OBJECT_LOCK (element);
612 result = GST_ELEMENT_START_TIME (element);
613 GST_OBJECT_UNLOCK (element);
619 * gst_element_is_indexable:
620 * @element: a #GstElement.
622 * Queries if the element can be indexed.
624 * Returns: TRUE if the element can be indexed.
629 gst_element_is_indexable (GstElement * element)
633 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
635 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
641 * gst_element_set_index:
642 * @element: a #GstElement.
643 * @index: a #GstIndex.
645 * Set @index on the element. The refcount of the index
646 * will be increased, any previously set index is unreffed.
651 gst_element_set_index (GstElement * element, GstIndex * index)
653 GstElementClass *oclass;
655 g_return_if_fail (GST_IS_ELEMENT (element));
656 g_return_if_fail (GST_IS_INDEX (index));
658 oclass = GST_ELEMENT_GET_CLASS (element);
660 if (oclass->set_index)
661 oclass->set_index (element, index);
665 * gst_element_get_index:
666 * @element: a #GstElement.
668 * Gets the index from the element.
670 * Returns: a #GstIndex or %NULL when no index was set on the
671 * element. unref after usage.
676 gst_element_get_index (GstElement * element)
678 GstElementClass *oclass;
679 GstIndex *result = NULL;
681 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
683 oclass = GST_ELEMENT_GET_CLASS (element);
685 if (oclass->get_index)
686 result = oclass->get_index (element);
692 * gst_element_add_pad:
693 * @element: a #GstElement to add the pad to.
694 * @pad: the #GstPad to add to the element.
696 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
697 * see gst_object_set_parent() for refcounting information.
699 * Pads are not automatically activated so elements should perform the needed
700 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
701 * state. See gst_pad_set_active() for more information about activating pads.
703 * The pad and the element should be unlocked when calling this function.
705 * This function will emit the #GstElement::pad-added signal on the element.
707 * Returns: %TRUE if the pad could be added. This function can fail when
708 * a pad with the same name already existed or the pad already had another
714 gst_element_add_pad (GstElement * element, GstPad * pad)
719 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
720 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
722 /* locking pad to look at the name */
723 GST_OBJECT_LOCK (pad);
724 pad_name = g_strdup (GST_PAD_NAME (pad));
725 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
726 GST_STR_NULL (pad_name));
727 flushing = GST_PAD_IS_FLUSHING (pad);
728 GST_OBJECT_UNLOCK (pad);
730 /* then check to see if there's already a pad by that name here */
731 GST_OBJECT_LOCK (element);
732 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
735 /* try to set the pad's parent */
736 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
737 GST_OBJECT_CAST (element))))
740 /* check for flushing pads */
741 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
742 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
743 g_warning ("adding flushing pad '%s' to running element '%s'",
744 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
746 GST_OBJECT_LOCK (pad);
747 GST_PAD_UNSET_FLUSHING (pad);
748 GST_OBJECT_UNLOCK (pad);
753 /* add it to the list */
754 switch (gst_pad_get_direction (pad)) {
756 element->srcpads = g_list_prepend (element->srcpads, pad);
757 element->numsrcpads++;
760 element->sinkpads = g_list_prepend (element->sinkpads, pad);
761 element->numsinkpads++;
766 element->pads = g_list_prepend (element->pads, pad);
768 element->pads_cookie++;
769 GST_OBJECT_UNLOCK (element);
771 /* emit the PAD_ADDED signal */
772 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
779 g_critical ("Padname %s is not unique in element %s, not adding",
780 pad_name, GST_ELEMENT_NAME (element));
781 GST_OBJECT_UNLOCK (element);
788 ("Pad %s already has parent when trying to add to element %s",
789 pad_name, GST_ELEMENT_NAME (element));
790 GST_OBJECT_UNLOCK (element);
796 GST_OBJECT_LOCK (pad);
798 ("Trying to add pad %s to element %s, but it has no direction",
799 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
800 GST_OBJECT_UNLOCK (pad);
801 GST_OBJECT_UNLOCK (element);
807 * gst_element_remove_pad:
808 * @element: a #GstElement to remove pad from.
809 * @pad: the #GstPad to remove from the element.
811 * Removes @pad from @element. @pad will be destroyed if it has not been
812 * referenced elsewhere using gst_object_unparent().
814 * This function is used by plugin developers and should not be used
815 * by applications. Pads that were dynamically requested from elements
816 * with gst_element_get_request_pad() should be released with the
817 * gst_element_release_request_pad() function instead.
819 * Pads are not automatically deactivated so elements should perform the needed
820 * steps to deactivate the pad in case this pad is removed in the PAUSED or
821 * PLAYING state. See gst_pad_set_active() for more information about
824 * The pad and the element should be unlocked when calling this function.
826 * This function will emit the #GstElement::pad-removed signal on the element.
828 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
829 * pad does not belong to the provided element.
834 gst_element_remove_pad (GstElement * element, GstPad * pad)
838 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
839 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
841 /* locking pad to look at the name and parent */
842 GST_OBJECT_LOCK (pad);
843 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
844 GST_STR_NULL (GST_PAD_NAME (pad)));
846 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
848 GST_OBJECT_UNLOCK (pad);
851 if ((peer = gst_pad_get_peer (pad))) {
852 /* window for MT unsafeness, someone else could unlink here
853 * and then we call unlink with wrong pads. The unlink
854 * function would catch this and safely return failed. */
855 if (GST_PAD_IS_SRC (pad))
856 gst_pad_unlink (pad, peer);
858 gst_pad_unlink (peer, pad);
860 gst_object_unref (peer);
863 GST_OBJECT_LOCK (element);
864 /* remove it from the list */
865 switch (gst_pad_get_direction (pad)) {
867 element->srcpads = g_list_remove (element->srcpads, pad);
868 element->numsrcpads--;
871 element->sinkpads = g_list_remove (element->sinkpads, pad);
872 element->numsinkpads--;
875 g_critical ("Removing pad without direction???");
878 element->pads = g_list_remove (element->pads, pad);
880 element->pads_cookie++;
881 GST_OBJECT_UNLOCK (element);
883 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
884 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
886 gst_object_unparent (GST_OBJECT_CAST (pad));
893 /* FIXME, locking order? */
894 GST_OBJECT_LOCK (element);
895 g_critical ("Padname %s:%s does not belong to element %s when removing",
896 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
897 GST_OBJECT_UNLOCK (element);
898 GST_OBJECT_UNLOCK (pad);
904 * gst_element_no_more_pads:
905 * @element: a #GstElement
907 * Use this function to signal that the element does not expect any more pads
908 * to show up in the current pipeline. This function should be called whenever
909 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
910 * pad templates use this in combination with autopluggers to figure out that
911 * the element is done initializing its pads.
913 * This function emits the #GstElement::no-more-pads signal.
918 gst_element_no_more_pads (GstElement * element)
920 g_return_if_fail (GST_IS_ELEMENT (element));
922 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
926 pad_compare_name (GstPad * pad1, const gchar * name)
930 GST_OBJECT_LOCK (pad1);
931 result = strcmp (GST_PAD_NAME (pad1), name);
932 GST_OBJECT_UNLOCK (pad1);
938 * gst_element_get_static_pad:
939 * @element: a #GstElement to find a static pad of.
940 * @name: the name of the static #GstPad to retrieve.
942 * Retrieves a pad from @element by name. This version only retrieves
943 * already-existing (i.e. 'static') pads.
945 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
951 gst_element_get_static_pad (GstElement * element, const gchar * name)
954 GstPad *result = NULL;
956 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
957 g_return_val_if_fail (name != NULL, NULL);
959 GST_OBJECT_LOCK (element);
961 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
963 result = GST_PAD_CAST (find->data);
964 gst_object_ref (result);
967 if (result == NULL) {
968 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
969 name, GST_ELEMENT_NAME (element));
971 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
972 GST_ELEMENT_NAME (element), name);
974 GST_OBJECT_UNLOCK (element);
980 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
983 GstPad *newpad = NULL;
984 GstElementClass *oclass;
986 oclass = GST_ELEMENT_GET_CLASS (element);
988 if (oclass->request_new_pad)
989 newpad = (oclass->request_new_pad) (element, templ, name);
992 gst_object_ref (newpad);
998 * gst_element_get_request_pad:
999 * @element: a #GstElement to find a request pad of.
1000 * @name: the name of the request #GstPad to retrieve.
1002 * Retrieves a pad from the element by name. This version only retrieves
1003 * request pads. The pad should be released with
1004 * gst_element_release_request_pad().
1006 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
1009 gst_element_get_request_pad (GstElement * element, const gchar * name)
1011 GstPadTemplate *templ = NULL;
1013 const gchar *req_name = NULL;
1014 gboolean templ_found = FALSE;
1018 gchar *str, *endptr = NULL;
1019 GstElementClass *class;
1021 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1022 g_return_val_if_fail (name != NULL, NULL);
1024 class = GST_ELEMENT_GET_CLASS (element);
1026 /* if the name contains a %, we assume it's the complete template name. Get
1027 * the template and try to get a pad */
1028 if (strstr (name, "%")) {
1029 templ = gst_element_class_get_request_pad_template (class, name);
1034 /* there is no % in the name, try to find a matching template */
1035 list = gst_element_class_get_pad_template_list (class);
1036 while (!templ_found && list) {
1037 templ = (GstPadTemplate *) list->data;
1038 if (templ->presence == GST_PAD_REQUEST) {
1039 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1040 templ->name_template);
1041 /* see if we find an exact match */
1042 if (strcmp (name, templ->name_template) == 0) {
1047 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1048 and %d, occurring at the end of the name_template, are the only
1050 else if ((str = strchr (templ->name_template, '%'))
1051 && strncmp (templ->name_template, name,
1052 str - templ->name_template) == 0
1053 && strlen (name) > str - templ->name_template) {
1054 data = name + (str - templ->name_template);
1055 if (*(str + 1) == 'd') {
1057 n = (gint) strtol (data, &endptr, 10);
1058 if (endptr && *endptr == '\0') {
1078 pad = gst_element_request_pad (element, templ, req_name);
1084 * gst_element_get_pad:
1085 * @element: a #GstElement.
1086 * @name: the name of the pad to retrieve.
1088 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
1089 * first, then gst_element_get_request_pad().
1091 * Deprecated: This function is deprecated as it's unclear if the reference
1092 * to the result pad should be released with gst_object_unref() in case of a static pad
1093 * or gst_element_release_request_pad() in case of a request pad.
1094 * Use gst_element_get_static_pad() or gst_element_get_request_pad() instead.
1096 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
1097 * depending on the type of the pad.
1099 #ifndef GST_REMOVE_DEPRECATED
1101 gst_element_get_pad (GstElement * element, const gchar * name)
1105 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1106 g_return_val_if_fail (name != NULL, NULL);
1108 pad = gst_element_get_static_pad (element, name);
1110 pad = gst_element_get_request_pad (element, name);
1114 #endif /* GST_REMOVE_DEPRECATED */
1116 static GstIteratorItem
1117 iterate_pad (GstIterator * it, GstPad * pad)
1119 gst_object_ref (pad);
1120 return GST_ITERATOR_ITEM_PASS;
1123 static GstIterator *
1124 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1126 GstIterator *result;
1128 GST_OBJECT_LOCK (element);
1129 gst_object_ref (element);
1130 result = gst_iterator_new_list (GST_TYPE_PAD,
1131 GST_OBJECT_GET_LOCK (element),
1132 &element->pads_cookie,
1135 (GstIteratorItemFunction) iterate_pad,
1136 (GstIteratorDisposeFunction) gst_object_unref);
1137 GST_OBJECT_UNLOCK (element);
1143 * gst_element_iterate_pads:
1144 * @element: a #GstElement to iterate pads of.
1146 * Retrieves an iterattor of @element's pads. The iterator should
1147 * be freed after usage.
1149 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1154 gst_element_iterate_pads (GstElement * element)
1156 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1158 return gst_element_iterate_pad_list (element, &element->pads);
1162 * gst_element_iterate_src_pads:
1163 * @element: a #GstElement.
1165 * Retrieves an iterator of @element's source pads.
1167 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1172 gst_element_iterate_src_pads (GstElement * element)
1174 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1176 return gst_element_iterate_pad_list (element, &element->srcpads);
1180 * gst_element_iterate_sink_pads:
1181 * @element: a #GstElement.
1183 * Retrieves an iterator of @element's sink pads.
1185 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1190 gst_element_iterate_sink_pads (GstElement * element)
1192 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1194 return gst_element_iterate_pad_list (element, &element->sinkpads);
1198 * gst_element_class_add_pad_template:
1199 * @klass: the #GstElementClass to add the pad template to.
1200 * @templ: a #GstPadTemplate to add to the element class.
1202 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1203 * functions of classes.
1206 gst_element_class_add_pad_template (GstElementClass * klass,
1207 GstPadTemplate * templ)
1209 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1210 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1212 /* FIXME 0.11: allow replacing the pad templates by
1213 * calling this with the same name as an already existing pad
1214 * template. For this we _must_ _not_ ref the added pad template
1215 * a second time and _must_ document that this function takes
1216 * ownership of the pad template. Otherwise we will leak pad templates
1217 * or the caller unref's the pad template and it disappears */
1218 /* avoid registering pad templates with the same name */
1219 g_return_if_fail (gst_element_class_get_pad_template (klass,
1220 templ->name_template) == NULL);
1222 klass->padtemplates = g_list_append (klass->padtemplates,
1223 gst_object_ref (templ));
1224 klass->numpadtemplates++;
1228 * gst_element_class_set_details:
1229 * @klass: class to set details for
1230 * @details: details to set
1232 * Sets the detailed information for a #GstElementClass.
1233 * <note>This function is for use in _base_init functions only.</note>
1235 * The @details are copied.
1238 gst_element_class_set_details (GstElementClass * klass,
1239 const GstElementDetails * details)
1241 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1242 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1244 __gst_element_details_copy (&klass->details, details);
1248 * gst_element_class_set_details_simple:
1249 * @klass: class to set details for
1250 * @longname: The long English name of the element. E.g. "File Sink"
1251 * @classification: String describing the type of element, as an unordered list
1252 * separated with slashes ('/'). See draft-klass.txt of the design docs
1253 * for more details and common types. E.g: "Sink/File"
1254 * @description: Sentence describing the purpose of the element.
1255 * E.g: "Write stream to a file"
1256 * @author: Name and contact details of the author(s). Use \n to separate
1257 * multiple author details. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1259 * Sets the detailed information for a #GstElementClass. Simpler version of
1260 * gst_element_class_set_details() that generates less linker overhead.
1261 * <note>This function is for use in _base_init functions only.</note>
1263 * The detail parameter strings are copied into the #GstElementDetails for
1264 * the element class.
1269 gst_element_class_set_details_simple (GstElementClass * klass,
1270 const gchar * longname, const gchar * classification,
1271 const gchar * description, const gchar * author)
1273 const GstElementDetails details =
1274 GST_ELEMENT_DETAILS ((gchar *) longname, (gchar *) classification,
1275 (gchar *) description, (gchar *) author);
1277 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1279 __gst_element_details_copy (&klass->details, &details);
1283 * gst_element_class_get_pad_template_list:
1284 * @element_class: a #GstElementClass to get pad templates of.
1286 * Retrieves a list of the pad templates associated with @element_class. The
1287 * list must not be modified by the calling code.
1288 * <note>If you use this function in the #GInstanceInitFunc of an object class
1289 * that has subclasses, make sure to pass the g_class parameter of the
1290 * #GInstanceInitFunc here.</note>
1292 * Returns: the #GList of padtemplates.
1295 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1297 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1299 return element_class->padtemplates;
1303 * gst_element_class_get_pad_template:
1304 * @element_class: a #GstElementClass to get the pad template of.
1305 * @name: the name of the #GstPadTemplate to get.
1307 * Retrieves a padtemplate from @element_class with the given name.
1308 * <note>If you use this function in the #GInstanceInitFunc of an object class
1309 * that has subclasses, make sure to pass the g_class parameter of the
1310 * #GInstanceInitFunc here.</note>
1312 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1313 * No unreferencing is necessary.
1316 gst_element_class_get_pad_template (GstElementClass * element_class,
1321 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1322 g_return_val_if_fail (name != NULL, NULL);
1324 padlist = gst_element_class_get_pad_template_list (element_class);
1327 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1329 if (strcmp (padtempl->name_template, name) == 0)
1332 padlist = g_list_next (padlist);
1338 static GstPadTemplate *
1339 gst_element_class_get_request_pad_template (GstElementClass * element_class,
1342 GstPadTemplate *tmpl;
1344 tmpl = gst_element_class_get_pad_template (element_class, name);
1345 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1351 /* get a random pad on element of the given direction.
1352 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1355 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1356 GstPadDirection dir)
1358 GstPad *result = NULL;
1361 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1365 GST_OBJECT_LOCK (element);
1366 pads = element->srcpads;
1369 GST_OBJECT_LOCK (element);
1370 pads = element->sinkpads;
1373 goto wrong_direction;
1375 for (; pads; pads = g_list_next (pads)) {
1376 GstPad *pad = GST_PAD_CAST (pads->data);
1378 GST_OBJECT_LOCK (pad);
1379 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1380 GST_DEBUG_PAD_NAME (pad));
1382 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1383 /* if we require a linked pad, and it is not linked, continue the
1385 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1386 GST_DEBUG_PAD_NAME (pad));
1387 GST_OBJECT_UNLOCK (pad);
1390 /* found a pad, stop search */
1391 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1392 GST_DEBUG_PAD_NAME (pad));
1393 GST_OBJECT_UNLOCK (pad);
1399 gst_object_ref (result);
1401 GST_OBJECT_UNLOCK (element);
1405 /* ERROR handling */
1408 g_warning ("unknown pad direction %d", dir);
1414 gst_element_default_send_event (GstElement * element, GstEvent * event)
1416 gboolean result = FALSE;
1419 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1420 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1421 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1424 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1425 "pushing %s event to random %s pad %s:%s",
1426 GST_EVENT_TYPE_NAME (event),
1427 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1428 GST_DEBUG_PAD_NAME (pad));
1430 result = gst_pad_push_event (pad, event);
1431 gst_object_unref (pad);
1433 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1434 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1440 * gst_element_send_event:
1441 * @element: a #GstElement to send the event to.
1442 * @event: the #GstEvent to send to the element.
1444 * Sends an event to an element. If the element doesn't implement an
1445 * event handler, the event will be pushed on a random linked sink pad for
1446 * upstream events or a random linked source pad for downstream events.
1448 * This function takes owership of the provided event so you should
1449 * gst_event_ref() it if you want to reuse the event after this call.
1451 * Returns: %TRUE if the event was handled.
1456 gst_element_send_event (GstElement * element, GstEvent * event)
1458 GstElementClass *oclass;
1459 gboolean result = FALSE;
1461 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1462 g_return_val_if_fail (event != NULL, FALSE);
1464 oclass = GST_ELEMENT_GET_CLASS (element);
1466 GST_STATE_LOCK (element);
1467 if (oclass->send_event) {
1468 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1469 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1470 result = oclass->send_event (element, event);
1472 result = gst_element_default_send_event (element, event);
1474 GST_STATE_UNLOCK (element);
1481 * @element: a #GstElement to send the event to.
1482 * @rate: The new playback rate
1483 * @format: The format of the seek values
1484 * @flags: The optional seek flags.
1485 * @cur_type: The type and flags for the new current position
1486 * @cur: The value of the new current position
1487 * @stop_type: The type and flags for the new stop position
1488 * @stop: The value of the new stop position
1490 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1491 * the parameters. The seek event is sent to the element using
1492 * gst_element_send_event().
1494 * Returns: %TRUE if the event was handled.
1499 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1500 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1501 GstSeekType stop_type, gint64 stop)
1506 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1509 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1510 result = gst_element_send_event (element, event);
1516 * gst_element_get_query_types:
1517 * @element: a #GstElement to query
1519 * Get an array of query types from the element.
1520 * If the element doesn't implement a query types function,
1521 * the query will be forwarded to the peer of a random linked sink pad.
1523 * Returns: An array of #GstQueryType elements that should not
1524 * be freed or modified.
1528 const GstQueryType *
1529 gst_element_get_query_types (GstElement * element)
1531 GstElementClass *oclass;
1532 const GstQueryType *result = NULL;
1534 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1536 oclass = GST_ELEMENT_GET_CLASS (element);
1538 if (oclass->get_query_types) {
1539 result = oclass->get_query_types (element);
1541 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1544 GstPad *peer = gst_pad_get_peer (pad);
1547 result = gst_pad_get_query_types (peer);
1549 gst_object_unref (peer);
1551 gst_object_unref (pad);
1558 gst_element_default_query (GstElement * element, GstQuery * query)
1560 gboolean result = FALSE;
1563 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1565 result = gst_pad_query (pad, query);
1567 gst_object_unref (pad);
1569 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1571 GstPad *peer = gst_pad_get_peer (pad);
1574 result = gst_pad_query (peer, query);
1576 gst_object_unref (peer);
1578 gst_object_unref (pad);
1585 * gst_element_query:
1586 * @element: a #GstElement to perform the query on.
1587 * @query: the #GstQuery.
1589 * Performs a query on the given element.
1591 * For elements that don't implement a query handler, this function
1592 * forwards the query to a random srcpad or to the peer of a
1593 * random linked sinkpad of this element.
1595 * Returns: TRUE if the query could be performed.
1600 gst_element_query (GstElement * element, GstQuery * query)
1602 GstElementClass *oclass;
1603 gboolean result = FALSE;
1605 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1606 g_return_val_if_fail (query != NULL, FALSE);
1608 oclass = GST_ELEMENT_GET_CLASS (element);
1610 if (oclass->query) {
1611 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1612 GST_ELEMENT_NAME (element));
1613 result = oclass->query (element, query);
1615 result = gst_element_default_query (element, query);
1621 * gst_element_post_message:
1622 * @element: a #GstElement posting the message
1623 * @message: a #GstMessage to post
1625 * Post a message on the element's #GstBus. This function takes ownership of the
1626 * message; if you want to access the message after this call, you should add an
1627 * additional reference before calling.
1629 * Returns: %TRUE if the message was successfully posted. The function returns
1630 * %FALSE if the element did not have a bus.
1635 gst_element_post_message (GstElement * element, GstMessage * message)
1638 gboolean result = FALSE;
1640 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1641 g_return_val_if_fail (message != NULL, FALSE);
1643 GST_OBJECT_LOCK (element);
1646 if (G_UNLIKELY (bus == NULL))
1649 gst_object_ref (bus);
1650 GST_OBJECT_UNLOCK (element);
1652 /* we release the element lock when posting the message so that any
1653 * (synchronous) message handlers can operate on the element */
1654 result = gst_bus_post (bus, message);
1655 gst_object_unref (bus);
1662 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1663 "not posting message %p: no bus", message);
1664 GST_OBJECT_UNLOCK (element);
1665 gst_message_unref (message);
1671 * _gst_element_error_printf:
1672 * @format: the printf-like format to use, or %NULL
1674 * This function is only used internally by the gst_element_error() macro.
1676 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1681 _gst_element_error_printf (const gchar * format, ...)
1691 va_start (args, format);
1692 buffer = g_strdup_vprintf (format, args);
1698 * gst_element_message_full:
1699 * @element: a #GstElement to send message from
1700 * @type: the #GstMessageType
1701 * @domain: the GStreamer GError domain this message belongs to
1702 * @code: the GError code belonging to the domain
1703 * @text: an allocated text string to be used as a replacement for the
1704 * default message connected to code, or %NULL
1705 * @debug: an allocated debug message to be used as a replacement for the
1706 * default debugging information, or %NULL
1707 * @file: the source code file where the error was generated
1708 * @function: the source code function where the error was generated
1709 * @line: the source code line where the error was generated
1711 * Post an error, warning or info message on the bus from inside an element.
1713 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1714 * #GST_MESSAGE_INFO.
1718 void gst_element_message_full
1719 (GstElement * element, GstMessageType type,
1720 GQuark domain, gint code, gchar * text,
1721 gchar * debug, const gchar * file, const gchar * function, gint line)
1723 GError *gerror = NULL;
1727 gboolean has_debug = TRUE;
1728 GstMessage *message = NULL;
1731 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1732 g_return_if_fail (GST_IS_ELEMENT (element));
1733 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1734 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1736 /* check if we send the given text or the default error text */
1737 if ((text == NULL) || (text[0] == 0)) {
1738 /* text could have come from g_strdup_printf (""); */
1740 sent_text = gst_error_get_message (domain, code);
1744 /* construct a sent_debug with extra information from source */
1745 if ((debug == NULL) || (debug[0] == 0)) {
1746 /* debug could have come from g_strdup_printf (""); */
1750 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1752 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1753 file, line, function, name, debug);
1755 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1756 file, line, function, name);
1760 /* create gerror and post message */
1761 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1763 gerror = g_error_new_literal (domain, code, sent_text);
1766 case GST_MESSAGE_ERROR:
1768 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1770 case GST_MESSAGE_WARNING:
1771 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1774 case GST_MESSAGE_INFO:
1775 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1779 g_assert_not_reached ();
1782 gst_element_post_message (element, message);
1784 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1785 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1788 g_error_free (gerror);
1789 g_free (sent_debug);
1794 * gst_element_is_locked_state:
1795 * @element: a #GstElement.
1797 * Checks if the state of an element is locked.
1798 * If the state of an element is locked, state changes of the parent don't
1799 * affect the element.
1800 * This way you can leave currently unused elements inside bins. Just lock their
1801 * state before changing the state from #GST_STATE_NULL.
1805 * Returns: TRUE, if the element's state is locked.
1808 gst_element_is_locked_state (GstElement * element)
1812 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1814 GST_OBJECT_LOCK (element);
1815 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1816 GST_OBJECT_UNLOCK (element);
1822 * gst_element_set_locked_state:
1823 * @element: a #GstElement
1824 * @locked_state: TRUE to lock the element's state
1826 * Locks the state of an element, so state changes of the parent don't affect
1827 * this element anymore.
1831 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1832 * or the elements state-locking needed no change.
1835 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1839 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1841 GST_OBJECT_LOCK (element);
1842 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1844 if (G_UNLIKELY (old == locked_state))
1848 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1849 GST_ELEMENT_NAME (element));
1850 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1852 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1853 GST_ELEMENT_NAME (element));
1854 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1856 GST_OBJECT_UNLOCK (element);
1862 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was already in locked state %d",
1863 GST_ELEMENT_NAME (element), old);
1864 GST_OBJECT_UNLOCK (element);
1871 * gst_element_sync_state_with_parent:
1872 * @element: a #GstElement.
1874 * Tries to change the state of the element to the same as its parent.
1875 * If this function returns FALSE, the state of element is undefined.
1877 * Returns: TRUE, if the element's state could be synced to the parent's state.
1882 gst_element_sync_state_with_parent (GstElement * element)
1886 GstStateChangeReturn ret;
1888 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1890 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1891 GstState parent_current, parent_pending;
1893 GST_OBJECT_LOCK (parent);
1894 parent_current = GST_STATE (parent);
1895 parent_pending = GST_STATE_PENDING (parent);
1896 GST_OBJECT_UNLOCK (parent);
1898 /* set to pending if there is one, else we set it to the current state of
1900 if (parent_pending != GST_STATE_VOID_PENDING)
1901 target = parent_pending;
1903 target = parent_current;
1905 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1906 "syncing state (%s) to parent %s %s (%s, %s)",
1907 gst_element_state_get_name (GST_STATE (element)),
1908 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1909 gst_element_state_get_name (parent_current),
1910 gst_element_state_get_name (parent_pending));
1912 ret = gst_element_set_state (element, target);
1913 if (ret == GST_STATE_CHANGE_FAILURE)
1916 gst_object_unref (parent);
1920 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1927 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1928 "syncing state failed (%s)",
1929 gst_element_state_change_return_get_name (ret));
1930 gst_object_unref (parent);
1936 static GstStateChangeReturn
1937 gst_element_get_state_func (GstElement * element,
1938 GstState * state, GstState * pending, GstClockTime timeout)
1940 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1941 GstState old_pending;
1943 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1944 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1946 GST_OBJECT_LOCK (element);
1947 ret = GST_STATE_RETURN (element);
1948 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1949 gst_element_state_change_return_get_name (ret));
1951 /* we got an error, report immediatly */
1952 if (ret == GST_STATE_CHANGE_FAILURE)
1955 /* we got no_preroll, report immediatly */
1956 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1959 /* no need to wait async if we are not async */
1960 if (ret != GST_STATE_CHANGE_ASYNC)
1963 old_pending = GST_STATE_PENDING (element);
1964 if (old_pending != GST_STATE_VOID_PENDING) {
1965 GTimeVal *timeval, abstimeout;
1968 if (timeout != GST_CLOCK_TIME_NONE) {
1969 glong add = timeout / 1000;
1974 /* make timeout absolute */
1975 g_get_current_time (&abstimeout);
1976 g_time_val_add (&abstimeout, add);
1977 timeval = &abstimeout;
1981 /* get cookie to detect state changes during waiting */
1982 cookie = element->state_cookie;
1984 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1985 "waiting for element to commit state");
1987 /* we have a pending state change, wait for it to complete */
1988 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1989 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1990 /* timeout triggered */
1991 ret = GST_STATE_CHANGE_ASYNC;
1993 if (cookie != element->state_cookie)
1996 /* could be success or failure */
1997 if (old_pending == GST_STATE (element)) {
1998 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1999 ret = GST_STATE_CHANGE_SUCCESS;
2001 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
2002 ret = GST_STATE_CHANGE_FAILURE;
2005 /* if nothing is pending anymore we can return SUCCESS */
2006 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
2007 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
2008 ret = GST_STATE_CHANGE_SUCCESS;
2014 *state = GST_STATE (element);
2016 *pending = GST_STATE_PENDING (element);
2018 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2019 "state current: %s, pending: %s, result: %s",
2020 gst_element_state_get_name (GST_STATE (element)),
2021 gst_element_state_get_name (GST_STATE_PENDING (element)),
2022 gst_element_state_change_return_get_name (ret));
2023 GST_OBJECT_UNLOCK (element);
2030 *state = GST_STATE_VOID_PENDING;
2032 *pending = GST_STATE_VOID_PENDING;
2034 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
2036 GST_OBJECT_UNLOCK (element);
2038 return GST_STATE_CHANGE_FAILURE;
2043 * gst_element_get_state:
2044 * @element: a #GstElement to get the state of.
2045 * @state: a pointer to #GstState to hold the state. Can be %NULL.
2046 * @pending: a pointer to #GstState to hold the pending state.
2048 * @timeout: a #GstClockTime to specify the timeout for an async
2049 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2051 * Gets the state of the element.
2053 * For elements that performed an ASYNC state change, as reported by
2054 * gst_element_set_state(), this function will block up to the
2055 * specified timeout value for the state change to complete.
2056 * If the element completes the state change or goes into
2057 * an error, this function returns immediately with a return value of
2058 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2060 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2061 * returns the current and pending state immediately.
2063 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2064 * successfully changed its state but is not able to provide data yet.
2065 * This mostly happens for live sources that only produce data in the PLAYING
2066 * state. While the state change return is equivalent to
2067 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2068 * some sink elements might not be able to complete their state change because
2069 * an element is not producing data to complete the preroll. When setting the
2070 * element to playing, the preroll will complete and playback will start.
2072 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2073 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2074 * element is still performing a state change or
2075 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2079 GstStateChangeReturn
2080 gst_element_get_state (GstElement * element,
2081 GstState * state, GstState * pending, GstClockTime timeout)
2083 GstElementClass *oclass;
2084 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2086 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2088 oclass = GST_ELEMENT_GET_CLASS (element);
2090 if (oclass->get_state)
2091 result = (oclass->get_state) (element, state, pending, timeout);
2097 * gst_element_abort_state:
2098 * @element: a #GstElement to abort the state of.
2100 * Abort the state change of the element. This function is used
2101 * by elements that do asynchronous state changes and find out
2102 * something is wrong.
2104 * This function should be called with the STATE_LOCK held.
2109 gst_element_abort_state (GstElement * element)
2113 #ifndef GST_DISABLE_GST_DEBUG
2117 g_return_if_fail (GST_IS_ELEMENT (element));
2119 GST_OBJECT_LOCK (element);
2120 pending = GST_STATE_PENDING (element);
2122 if (pending == GST_STATE_VOID_PENDING ||
2123 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2124 goto nothing_aborted;
2126 #ifndef GST_DISABLE_GST_DEBUG
2127 old_state = GST_STATE (element);
2129 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2130 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2131 gst_element_state_get_name (pending));
2135 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2137 GST_STATE_BROADCAST (element);
2138 GST_OBJECT_UNLOCK (element);
2144 GST_OBJECT_UNLOCK (element);
2150 * gst_element_continue_state:
2151 * @element: a #GstElement to continue the state change of.
2152 * @ret: The previous state return value
2154 * Commit the state change of the element and proceed to the next
2155 * pending state if any. This function is used
2156 * by elements that do asynchronous state changes.
2157 * The core will normally call this method automatically when an
2158 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2160 * If after calling this method the element still has not reached
2161 * the pending state, the next state change is performed.
2163 * This method is used internally and should normally not be called by plugins
2166 * Returns: The result of the commit state change.
2170 GstStateChangeReturn
2171 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2173 GstStateChangeReturn old_ret;
2174 GstState old_state, old_next;
2175 GstState current, next, pending;
2176 GstMessage *message;
2177 GstStateChange transition;
2179 GST_OBJECT_LOCK (element);
2180 old_ret = GST_STATE_RETURN (element);
2181 GST_STATE_RETURN (element) = ret;
2182 pending = GST_STATE_PENDING (element);
2184 /* check if there is something to commit */
2185 if (pending == GST_STATE_VOID_PENDING)
2186 goto nothing_pending;
2188 old_state = GST_STATE (element);
2189 /* this is the state we should go to next */
2190 old_next = GST_STATE_NEXT (element);
2191 /* update current state */
2192 current = GST_STATE (element) = old_next;
2194 /* see if we reached the final state */
2195 if (pending == current)
2198 next = GST_STATE_GET_NEXT (current, pending);
2199 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2201 GST_STATE_NEXT (element) = next;
2203 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2204 GST_OBJECT_UNLOCK (element);
2206 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2207 "committing state from %s to %s, pending %s, next %s",
2208 gst_element_state_get_name (old_state),
2209 gst_element_state_get_name (old_next),
2210 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2212 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2213 old_state, old_next, pending);
2214 gst_element_post_message (element, message);
2216 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2217 "continue state change %s to %s, final %s",
2218 gst_element_state_get_name (current),
2219 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2221 ret = gst_element_change_state (element, transition);
2227 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2228 GST_OBJECT_UNLOCK (element);
2233 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2234 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2236 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2237 "completed state change to %s", gst_element_state_get_name (pending));
2238 GST_OBJECT_UNLOCK (element);
2240 /* don't post silly messages with the same state. This can happen
2241 * when an element state is changed to what it already was. For bins
2242 * this can be the result of a lost state, which we check with the
2243 * previous return value.
2244 * We do signal the cond though as a _get_state() might be blocking
2246 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2247 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2248 "posting state-changed %s to %s",
2249 gst_element_state_get_name (old_state),
2250 gst_element_state_get_name (old_next));
2252 gst_message_new_state_changed (GST_OBJECT_CAST (element), old_state,
2253 old_next, GST_STATE_VOID_PENDING);
2254 gst_element_post_message (element, message);
2257 GST_STATE_BROADCAST (element);
2264 * gst_element_lost_state_full:
2265 * @element: a #GstElement the state is lost of
2266 * @new_base_time: if a new base time should be distributed
2268 * Brings the element to the lost state. The current state of the
2269 * element is copied to the pending state so that any call to
2270 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2272 * An ASYNC_START message is posted with indication to distribute a new
2273 * base_time to the element when @new_base_time is %TRUE.
2274 * If the element was PLAYING, it will go to PAUSED. The element
2275 * will be restored to its PLAYING state by the parent pipeline when it
2278 * This is mostly used for elements that lost their preroll buffer
2279 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2280 * they will go to their pending state again when a new preroll buffer is
2281 * queued. This function can only be called when the element is currently
2282 * not in error or an async state change.
2284 * This function is used internally and should normally not be called from
2285 * plugins or applications.
2292 gst_element_lost_state_full (GstElement * element, gboolean new_base_time)
2294 GstState old_state, new_state;
2295 GstMessage *message;
2297 g_return_if_fail (GST_IS_ELEMENT (element));
2299 GST_OBJECT_LOCK (element);
2300 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2303 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2304 goto only_async_start;
2306 old_state = GST_STATE (element);
2308 /* when we were PLAYING, the new state is PAUSED. We will also not
2309 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2310 * when we preroll. */
2311 if (old_state > GST_STATE_PAUSED)
2312 new_state = GST_STATE_PAUSED;
2314 new_state = old_state;
2316 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2317 "lost state of %s to %s", gst_element_state_get_name (old_state),
2318 gst_element_state_get_name (new_state));
2320 GST_STATE (element) = new_state;
2321 GST_STATE_NEXT (element) = new_state;
2322 GST_STATE_PENDING (element) = new_state;
2323 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2325 GST_ELEMENT_START_TIME (element) = 0;
2326 GST_OBJECT_UNLOCK (element);
2328 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2329 new_state, new_state, new_state);
2330 gst_element_post_message (element, message);
2333 gst_message_new_async_start (GST_OBJECT_CAST (element), new_base_time);
2334 gst_element_post_message (element, message);
2340 GST_OBJECT_UNLOCK (element);
2345 GST_OBJECT_UNLOCK (element);
2347 message = gst_message_new_async_start (GST_OBJECT_CAST (element), TRUE);
2348 gst_element_post_message (element, message);
2354 * gst_element_lost_state:
2355 * @element: a #GstElement the state is lost of
2357 * Brings the element to the lost state. This function calls
2358 * gst_element_lost_state_full() with the new_base_time set to %TRUE.
2360 * This function is used internally and should normally not be called from
2361 * plugins or applications.
2366 gst_element_lost_state (GstElement * element)
2368 gst_element_lost_state_full (element, TRUE);
2372 * gst_element_set_state:
2373 * @element: a #GstElement to change state of.
2374 * @state: the element's new #GstState.
2376 * Sets the state of the element. This function will try to set the
2377 * requested state by going through all the intermediary states and calling
2378 * the class's state change function for each.
2380 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2381 * element will perform the remainder of the state change asynchronously in
2383 * An application can use gst_element_get_state() to wait for the completion
2384 * of the state change or it can wait for a state change message on the bus.
2386 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2387 * #GST_STATE_CHANGE_ASYNC.
2389 * Returns: Result of the state change using #GstStateChangeReturn.
2393 GstStateChangeReturn
2394 gst_element_set_state (GstElement * element, GstState state)
2396 GstElementClass *oclass;
2397 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2399 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2401 oclass = GST_ELEMENT_GET_CLASS (element);
2403 if (oclass->set_state)
2404 result = (oclass->set_state) (element, state);
2410 * default set state function, calculates the next state based
2411 * on current state and calls the change_state function
2413 static GstStateChangeReturn
2414 gst_element_set_state_func (GstElement * element, GstState state)
2416 GstState current, next, old_pending;
2417 GstStateChangeReturn ret;
2418 GstStateChange transition;
2419 GstStateChangeReturn old_ret;
2421 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2423 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2424 gst_element_state_get_name (state));
2426 /* state lock is taken to protect the set_state() and get_state()
2427 * procedures, it does not lock any variables. */
2428 GST_STATE_LOCK (element);
2430 /* now calculate how to get to the new state */
2431 GST_OBJECT_LOCK (element);
2432 old_ret = GST_STATE_RETURN (element);
2433 /* previous state change returned an error, remove all pending
2434 * and next states */
2435 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2436 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2437 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2438 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2441 current = GST_STATE (element);
2442 next = GST_STATE_NEXT (element);
2443 old_pending = GST_STATE_PENDING (element);
2445 /* this is the (new) state we should go to. TARGET is the last state we set on
2447 if (state != GST_STATE_TARGET (element)) {
2448 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2449 "setting target state to %s", gst_element_state_get_name (state));
2450 GST_STATE_TARGET (element) = state;
2451 /* increment state cookie so that we can track each state change. We only do
2452 * this if this is actually a new state change. */
2453 element->state_cookie++;
2455 GST_STATE_PENDING (element) = state;
2457 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2458 "current %s, old_pending %s, next %s, old return %s",
2459 gst_element_state_get_name (current),
2460 gst_element_state_get_name (old_pending),
2461 gst_element_state_get_name (next),
2462 gst_element_state_change_return_get_name (old_ret));
2464 /* if the element was busy doing a state change, we just update the
2465 * target state, it'll get to it async then. */
2466 if (old_pending != GST_STATE_VOID_PENDING) {
2467 /* upwards state change will happen ASYNC */
2468 if (old_pending <= state)
2470 /* element is going to this state already */
2471 else if (next == state)
2473 /* element was performing an ASYNC upward state change and
2474 * we request to go downward again. Start from the next pending
2476 else if (next > state
2477 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2481 next = GST_STATE_GET_NEXT (current, state);
2482 /* now we store the next state */
2483 GST_STATE_NEXT (element) = next;
2484 /* mark busy, we need to check that there is actually a state change
2485 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2486 * the default element change_state function has no way to know what the
2487 * old value was... could consider this a FIXME...*/
2488 if (current != next)
2489 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2491 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2493 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2494 "%s: setting state from %s to %s",
2495 (next != state ? "intermediate" : "final"),
2496 gst_element_state_get_name (current), gst_element_state_get_name (next));
2498 /* now signal any waiters, they will error since the cookie was incremented */
2499 GST_STATE_BROADCAST (element);
2501 GST_OBJECT_UNLOCK (element);
2503 ret = gst_element_change_state (element, transition);
2505 GST_STATE_UNLOCK (element);
2507 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2508 gst_element_state_change_return_get_name (ret));
2514 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2515 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2516 "element was busy with async state change");
2517 GST_OBJECT_UNLOCK (element);
2519 GST_STATE_UNLOCK (element);
2521 return GST_STATE_CHANGE_ASYNC;
2526 * gst_element_change_state:
2527 * @element: a #GstElement
2528 * @transition: the requested transition
2530 * Perform @transition on @element.
2532 * This function must be called with STATE_LOCK held and is mainly used
2535 * Returns: the #GstStateChangeReturn of the state transition.
2537 GstStateChangeReturn
2538 gst_element_change_state (GstElement * element, GstStateChange transition)
2540 GstElementClass *oclass;
2541 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2543 oclass = GST_ELEMENT_GET_CLASS (element);
2545 /* call the state change function so it can set the state */
2546 if (oclass->change_state)
2547 ret = (oclass->change_state) (element, transition);
2549 ret = GST_STATE_CHANGE_FAILURE;
2552 case GST_STATE_CHANGE_FAILURE:
2553 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2554 "have FAILURE change_state return");
2555 /* state change failure */
2556 gst_element_abort_state (element);
2558 case GST_STATE_CHANGE_ASYNC:
2562 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2563 "element will change state ASYNC");
2565 target = GST_STATE_TARGET (element);
2567 if (target > GST_STATE_READY)
2570 /* else we just continue the state change downwards */
2571 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2572 "forcing commit state %s <= %s",
2573 gst_element_state_get_name (target),
2574 gst_element_state_get_name (GST_STATE_READY));
2576 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2579 case GST_STATE_CHANGE_SUCCESS:
2580 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2581 "element changed state SUCCESS");
2582 /* we can commit the state now which will proceeed to
2584 ret = gst_element_continue_state (element, ret);
2586 case GST_STATE_CHANGE_NO_PREROLL:
2587 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2588 "element changed state NO_PREROLL");
2589 /* we can commit the state now which will proceeed to
2591 ret = gst_element_continue_state (element, ret);
2594 goto invalid_return;
2597 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2602 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2610 GST_OBJECT_LOCK (element);
2611 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2612 g_critical ("%s: unknown return value %d from a state change function",
2613 GST_ELEMENT_NAME (element), ret);
2615 /* we are in error now */
2616 ret = GST_STATE_CHANGE_FAILURE;
2617 GST_STATE_RETURN (element) = ret;
2618 GST_OBJECT_UNLOCK (element);
2624 /* gst_iterator_fold functions for pads_activate
2625 * Note how we don't stop the iterator when we fail an activation. This is
2626 * probably a FIXME since when one pad activation fails, we don't want to
2627 * continue our state change. */
2629 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2631 if (!gst_pad_set_active (pad, *active))
2632 g_value_set_boolean (ret, FALSE);
2634 /* unref the object that was reffed for us by _fold */
2635 gst_object_unref (pad);
2639 /* set the caps on the pad to NULL */
2641 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2643 gst_pad_set_caps (pad, NULL);
2644 gst_object_unref (pad);
2648 /* returns false on error or early cutout (will never happen because the fold
2649 * function always returns TRUE, see FIXME above) of the fold, true if all
2650 * pads in @iter were (de)activated successfully. */
2652 iterator_activate_fold_with_resync (GstIterator * iter,
2653 GstIteratorFoldFunction func, gpointer user_data)
2655 GstIteratorResult ires;
2658 /* no need to unset this later, it's just a boolean */
2659 g_value_init (&ret, G_TYPE_BOOLEAN);
2660 g_value_set_boolean (&ret, TRUE);
2663 ires = gst_iterator_fold (iter, func, &ret, user_data);
2665 case GST_ITERATOR_RESYNC:
2666 /* need to reset the result again */
2667 g_value_set_boolean (&ret, TRUE);
2668 gst_iterator_resync (iter);
2670 case GST_ITERATOR_DONE:
2671 /* all pads iterated, return collected value */
2674 /* iterator returned _ERROR or premature end with _OK,
2675 * mark an error and exit */
2676 g_value_set_boolean (&ret, FALSE);
2681 /* return collected value */
2682 return g_value_get_boolean (&ret);
2685 /* is called with STATE_LOCK
2687 * Pads are activated from source pads to sinkpads.
2690 gst_element_pads_activate (GstElement * element, gboolean active)
2695 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2696 "pads_activate with active %d", active);
2698 iter = gst_element_iterate_src_pads (element);
2700 iterator_activate_fold_with_resync (iter,
2701 (GstIteratorFoldFunction) activate_pads, &active);
2702 gst_iterator_free (iter);
2703 if (G_UNLIKELY (!res))
2706 iter = gst_element_iterate_sink_pads (element);
2708 iterator_activate_fold_with_resync (iter,
2709 (GstIteratorFoldFunction) activate_pads, &active);
2710 gst_iterator_free (iter);
2711 if (G_UNLIKELY (!res))
2715 /* clear the caps on all pads, this should never fail */
2716 iter = gst_element_iterate_pads (element);
2718 iterator_activate_fold_with_resync (iter,
2719 (GstIteratorFoldFunction) clear_caps, &active);
2720 gst_iterator_free (iter);
2721 if (G_UNLIKELY (!res))
2725 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2726 "pads_activate successful");
2733 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2734 "source pads_activate failed");
2739 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2740 "sink pads_activate failed");
2745 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2746 "failed to clear caps on pads");
2751 /* is called with STATE_LOCK */
2752 static GstStateChangeReturn
2753 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2755 GstState state, next;
2756 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2759 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2761 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2762 next = GST_STATE_TRANSITION_NEXT (transition);
2764 /* if the element already is in the given state, we just return success */
2765 if (next == GST_STATE_VOID_PENDING || state == next)
2768 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2769 "default handler tries setting state from %s to %s (%04x)",
2770 gst_element_state_get_name (state),
2771 gst_element_state_get_name (next), transition);
2773 switch (transition) {
2774 case GST_STATE_CHANGE_NULL_TO_READY:
2776 case GST_STATE_CHANGE_READY_TO_PAUSED:
2777 if (!gst_element_pads_activate (element, TRUE)) {
2778 result = GST_STATE_CHANGE_FAILURE;
2781 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2783 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2785 case GST_STATE_CHANGE_PAUSED_TO_READY:
2786 case GST_STATE_CHANGE_READY_TO_NULL:
2787 /* deactivate pads in both cases, since they are activated on
2788 ready->paused but the element might not have made it to paused */
2789 if (!gst_element_pads_activate (element, FALSE)) {
2790 result = GST_STATE_CHANGE_FAILURE;
2792 gst_element_set_base_time (element, 0);
2795 /* In null state release the reference to the clock */
2796 GST_OBJECT_LOCK (element);
2797 clock_p = &element->clock;
2798 gst_object_replace ((GstObject **) clock_p, NULL);
2799 GST_OBJECT_UNLOCK (element);
2802 /* this will catch real but unhandled state changes;
2803 * can only be caused by:
2804 * - a new state was added
2805 * - somehow the element was asked to jump across an intermediate state
2807 g_warning ("Unhandled state change from %s to %s",
2808 gst_element_state_get_name (state),
2809 gst_element_state_get_name (next));
2816 GST_OBJECT_LOCK (element);
2817 result = GST_STATE_RETURN (element);
2818 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2819 "element is already in the %s state",
2820 gst_element_state_get_name (state));
2821 GST_OBJECT_UNLOCK (element);
2828 * gst_element_get_factory:
2829 * @element: a #GstElement to request the element factory of.
2831 * Retrieves the factory that was used to create this element.
2833 * Returns: the #GstElementFactory used for creating this element.
2834 * no refcounting is needed.
2837 gst_element_get_factory (GstElement * element)
2839 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2841 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2845 gst_element_dispose (GObject * object)
2847 GstElement *element = GST_ELEMENT (object);
2851 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2853 if (GST_STATE (element) != GST_STATE_NULL)
2856 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2857 "removing %d pads", g_list_length (element->pads));
2858 /* first we break all our links with the outside */
2859 while (element->pads && element->pads->data) {
2860 /* don't call _remove_pad with NULL */
2861 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2863 if (G_UNLIKELY (element->pads != 0)) {
2864 g_critical ("could not remove pads from element %s",
2865 GST_STR_NULL (GST_OBJECT_NAME (object)));
2868 GST_OBJECT_LOCK (element);
2869 clock_p = &element->clock;
2870 bus_p = &element->bus;
2871 gst_object_replace ((GstObject **) clock_p, NULL);
2872 gst_object_replace ((GstObject **) bus_p, NULL);
2873 GST_OBJECT_UNLOCK (element);
2875 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2877 G_OBJECT_CLASS (parent_class)->dispose (object);
2885 ("\nTrying to dispose element %s, but it is not in the NULL state.\n"
2886 "You need to explicitly set elements to the NULL state before\n"
2887 "dropping the final reference, to allow them to clean up.\n",
2888 GST_OBJECT_NAME (element));
2894 gst_element_finalize (GObject * object)
2896 GstElement *element = GST_ELEMENT (object);
2898 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2900 GST_STATE_LOCK (element);
2901 if (element->state_cond)
2902 g_cond_free (element->state_cond);
2903 element->state_cond = NULL;
2904 GST_STATE_UNLOCK (element);
2905 g_static_rec_mutex_free (element->state_lock);
2906 g_free (element->state_lock);
2907 element->state_lock = NULL;
2909 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2911 G_OBJECT_CLASS (parent_class)->finalize (object);
2914 #ifndef GST_DISABLE_LOADSAVE
2916 * gst_element_save_thyself:
2917 * @element: a #GstElement to save.
2918 * @parent: the xml parent node.
2920 * Saves the element as part of the given XML structure.
2922 * Returns: the new #xmlNodePtr.
2925 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2928 GstElementClass *oclass;
2929 GParamSpec **specs, *spec;
2932 GValue value = { 0, };
2933 GstElement *element;
2935 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2937 element = GST_ELEMENT (object);
2939 oclass = GST_ELEMENT_GET_CLASS (element);
2941 xmlNewChild (parent, NULL, (xmlChar *) "name",
2942 (xmlChar *) GST_ELEMENT_NAME (element));
2944 if (oclass->elementfactory != NULL) {
2945 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2947 xmlNewChild (parent, NULL, (xmlChar *) "type",
2948 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2952 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2954 for (i = 0; i < nspecs; i++) {
2956 if (spec->flags & G_PARAM_READABLE) {
2960 g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (spec));
2962 g_object_get_property (G_OBJECT (element), spec->name, &value);
2963 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2964 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2966 if (G_IS_PARAM_SPEC_STRING (spec))
2967 contents = g_value_dup_string (&value);
2968 else if (G_IS_PARAM_SPEC_ENUM (spec))
2969 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2970 else if (G_IS_PARAM_SPEC_INT64 (spec))
2971 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2972 g_value_get_int64 (&value));
2973 else if (GST_VALUE_HOLDS_STRUCTURE (&value)) {
2974 if (g_value_get_boxed (&value) != NULL) {
2975 contents = g_strdup_value_contents (&value);
2977 contents = g_strdup ("NULL");
2980 contents = g_strdup_value_contents (&value);
2982 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2985 g_value_unset (&value);
2991 pads = g_list_last (GST_ELEMENT_PADS (element));
2994 GstPad *pad = GST_PAD_CAST (pads->data);
2996 /* figure out if it's a direct pad or a ghostpad */
2997 if (GST_ELEMENT (GST_OBJECT_PARENT (pad)) == element) {
2998 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
3000 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
3002 pads = g_list_previous (pads);
3009 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
3011 xmlNodePtr children;
3012 GstElement *element;
3014 gchar *value = NULL;
3016 element = GST_ELEMENT (object);
3017 g_return_if_fail (element != NULL);
3020 children = self->xmlChildrenNode;
3022 if (!strcmp ((char *) children->name, "param")) {
3023 xmlNodePtr child = children->xmlChildrenNode;
3026 if (!strcmp ((char *) child->name, "name")) {
3027 name = (gchar *) xmlNodeGetContent (child);
3028 } else if (!strcmp ((char *) child->name, "value")) {
3029 value = (gchar *) xmlNodeGetContent (child);
3031 child = child->next;
3033 /* FIXME: can this just be g_object_set ? */
3034 gst_util_set_object_arg (G_OBJECT (element), name, value);
3035 /* g_object_set (G_OBJECT (element), name, value, NULL); */
3039 children = children->next;
3043 children = self->xmlChildrenNode;
3045 if (!strcmp ((char *) children->name, "pad")) {
3046 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
3048 children = children->next;
3051 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
3052 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
3054 #endif /* GST_DISABLE_LOADSAVE */
3057 gst_element_set_bus_func (GstElement * element, GstBus * bus)
3061 g_return_if_fail (GST_IS_ELEMENT (element));
3063 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
3065 GST_OBJECT_LOCK (element);
3066 bus_p = &GST_ELEMENT_BUS (element);
3067 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
3068 GST_OBJECT_UNLOCK (element);
3072 * gst_element_set_bus:
3073 * @element: a #GstElement to set the bus of.
3074 * @bus: the #GstBus to set.
3076 * Sets the bus of the element. Increases the refcount on the bus.
3077 * For internal use only, unless you're testing elements.
3082 gst_element_set_bus (GstElement * element, GstBus * bus)
3084 GstElementClass *oclass;
3086 g_return_if_fail (GST_IS_ELEMENT (element));
3088 oclass = GST_ELEMENT_GET_CLASS (element);
3090 if (oclass->set_bus)
3091 oclass->set_bus (element, bus);
3095 * gst_element_get_bus:
3096 * @element: a #GstElement to get the bus of.
3098 * Returns the bus of the element. Note that only a #GstPipeline will provide a
3099 * bus for the application.
3101 * Returns: the element's #GstBus. unref after usage.
3106 gst_element_get_bus (GstElement * element)
3108 GstBus *result = NULL;
3110 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
3112 GST_OBJECT_LOCK (element);
3113 if ((result = GST_ELEMENT_BUS (element)))
3114 gst_object_ref (result);
3115 GST_OBJECT_UNLOCK (element);
3117 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,