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 2006-03-12 (0.10.5)
79 #include "gst_private.h"
82 #include <gobject/gvaluecollector.h>
84 #include "gstelement.h"
86 #include "gstmarshal.h"
91 #include "gst-i18n-lib.h"
93 /* Element signals and args */
109 extern void __gst_element_details_clear (GstElementDetails * dp);
110 extern void __gst_element_details_copy (GstElementDetails * dest,
111 const GstElementDetails * src);
113 static void gst_element_class_init (GstElementClass * klass);
114 static void gst_element_init (GstElement * element);
115 static void gst_element_base_class_init (gpointer g_class);
116 static void gst_element_base_class_finalize (gpointer g_class);
118 static void gst_element_dispose (GObject * object);
119 static void gst_element_finalize (GObject * object);
121 static GstStateChangeReturn gst_element_change_state (GstElement * element,
122 GstStateChange transition);
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 #ifndef GST_DISABLE_LOADSAVE
137 static xmlNodePtr gst_element_save_thyself (GstObject * object,
139 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
142 static GstObjectClass *parent_class = NULL;
143 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
146 gst_element_get_type (void)
148 static GType gst_element_type = 0;
150 if (G_UNLIKELY (gst_element_type == 0)) {
151 static const GTypeInfo element_info = {
152 sizeof (GstElementClass),
153 gst_element_base_class_init,
154 gst_element_base_class_finalize,
155 (GClassInitFunc) gst_element_class_init,
160 (GInstanceInitFunc) gst_element_init,
164 gst_element_type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
165 &element_info, G_TYPE_FLAG_ABSTRACT);
167 return gst_element_type;
171 gst_element_class_init (GstElementClass * klass)
173 GObjectClass *gobject_class;
174 GstObjectClass *gstobject_class;
176 gobject_class = (GObjectClass *) klass;
177 gstobject_class = (GstObjectClass *) klass;
179 parent_class = g_type_class_peek_parent (klass);
182 * GstElement::pad-added:
183 * @gstelement: the object which received the signal
184 * @new_pad: the pad that has been added
186 * a new #GstPad has been added to the element.
188 gst_element_signals[PAD_ADDED] =
189 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
190 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
191 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, G_TYPE_OBJECT);
193 * GstElement::pad-removed:
194 * @gstelement: the object which received the signal
195 * @old_pad: the pad that has been removed
197 * a #GstPad has been removed from the element
199 gst_element_signals[PAD_REMOVED] =
200 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
201 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
202 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, G_TYPE_OBJECT);
204 * GstElement::no-more-pads:
205 * @gstelement: the object which received the signal
207 * This signals that the element will not generate more dynamic pads.
209 gst_element_signals[NO_MORE_PADS] =
210 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
211 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
212 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
214 gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_element_dispose);
215 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_finalize);
217 #ifndef GST_DISABLE_LOADSAVE
218 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
219 gstobject_class->restore_thyself =
220 GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
223 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
224 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
225 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
226 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
227 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
228 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
229 klass->numpadtemplates = 0;
231 klass->elementfactory = NULL;
235 gst_element_base_class_init (gpointer g_class)
237 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
239 memset (&element_class->details, 0, sizeof (GstElementDetails));
240 element_class->padtemplates = NULL;
244 gst_element_base_class_finalize (gpointer g_class)
246 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
248 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
249 g_list_free (klass->padtemplates);
250 __gst_element_details_clear (&klass->details);
254 gst_element_init (GstElement * element)
256 GST_STATE (element) = GST_STATE_NULL;
257 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
258 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
259 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
261 element->state_lock = g_new0 (GStaticRecMutex, 1);
262 g_static_rec_mutex_init (element->state_lock);
263 element->state_cond = g_cond_new ();
267 * gst_element_default_error:
268 * @object: a #GObject that signalled the error.
269 * @orig: the #GstObject that initiated the error.
270 * @error: the GError.
271 * @debug: an additional debug information string, or %NULL.
273 * A default error signal callback to attach to an element.
274 * The user data passed to the g_signal_connect is ignored.
276 * The default handler will simply print the error string using g_print.
281 gst_element_default_error (GObject * object, GstObject * source, GError * error,
284 gchar *name = gst_object_get_path_string (source);
286 g_print (_("ERROR: from element %s: %s\n"), name, error->message);
288 g_print (_("Additional debug info:\n%s\n"), debug);
294 * gst_element_release_request_pad:
295 * @element: a #GstElement to release the request pad of.
296 * @pad: the #GstPad to release.
298 * Makes the element free the previously requested pad as obtained
299 * with gst_element_get_request_pad().
304 gst_element_release_request_pad (GstElement * element, GstPad * pad)
306 GstElementClass *oclass;
308 g_return_if_fail (GST_IS_ELEMENT (element));
309 g_return_if_fail (GST_IS_PAD (pad));
311 oclass = GST_ELEMENT_GET_CLASS (element);
313 /* if the element implements a custom release function we call that, else we
314 * simply remove the pad from the element */
315 if (oclass->release_pad)
316 (oclass->release_pad) (element, pad);
318 gst_element_remove_pad (element, pad);
322 * gst_element_requires_clock:
323 * @element: a #GstElement to query
325 * Query if the element requires a clock.
327 * Returns: %TRUE if the element requires a clock
332 gst_element_requires_clock (GstElement * element)
336 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
338 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
344 * gst_element_provides_clock:
345 * @element: a #GstElement to query
347 * Query if the element provides a clock. A #GstClock provided by an
348 * element can be used as the global #GstClock for the pipeline.
349 * An element that can provide a clock is only required to do so in the PAUSED
350 * state, this means when it is fully negotiated and has allocated the resources
351 * to operate the clock.
353 * Returns: %TRUE if the element provides a clock
358 gst_element_provides_clock (GstElement * element)
362 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
364 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
370 * gst_element_provide_clock:
371 * @element: a #GstElement to query
373 * Get the clock provided by the given element.
374 * <note>An element is only required to provide a clock in the PAUSED
375 * state. Some elements can provide a clock in other states.</note>
377 * Returns: the GstClock provided by the element or %NULL
378 * if no clock could be provided. Unref after usage.
383 gst_element_provide_clock (GstElement * element)
385 GstClock *result = NULL;
386 GstElementClass *oclass;
388 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
390 oclass = GST_ELEMENT_GET_CLASS (element);
392 if (oclass->provide_clock)
393 result = oclass->provide_clock (element);
399 * gst_element_set_clock:
400 * @element: a #GstElement to set the clock for.
401 * @clock: the #GstClock to set for the element.
403 * Sets the clock for the element. This function increases the
404 * refcount on the clock. Any previously set clock on the object
407 * Returns: %TRUE if the element accepted the clock. An element can refuse a
408 * clock when it, for example, is not able to slave its internal clock to the
409 * @clock or when it requires a specific clock to operate.
414 gst_element_set_clock (GstElement * element, GstClock * clock)
416 GstElementClass *oclass;
420 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
422 oclass = GST_ELEMENT_GET_CLASS (element);
424 GST_DEBUG_OBJECT (element, "setting clock %p", clock);
426 if (oclass->set_clock)
427 res = oclass->set_clock (element, clock);
430 /* only update the clock pointer if the element accepted the clock */
431 GST_OBJECT_LOCK (element);
432 clock_p = &element->clock;
433 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
434 GST_OBJECT_UNLOCK (element);
440 * gst_element_get_clock:
441 * @element: a #GstElement to get the clock of.
443 * Gets the currently configured clock of the element. This is the clock as was
444 * last set with gst_element_set_clock().
446 * Returns: the #GstClock of the element. unref after usage.
451 gst_element_get_clock (GstElement * element)
455 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
457 GST_OBJECT_LOCK (element);
458 if ((result = element->clock))
459 gst_object_ref (result);
460 GST_OBJECT_UNLOCK (element);
466 * gst_element_set_base_time:
467 * @element: a #GstElement.
468 * @time: the base time to set.
470 * Set the base time of an element. See gst_element_get_base_time().
475 gst_element_set_base_time (GstElement * element, GstClockTime time)
477 g_return_if_fail (GST_IS_ELEMENT (element));
479 GST_OBJECT_LOCK (element);
480 element->base_time = time;
481 GST_OBJECT_UNLOCK (element);
483 GST_DEBUG_OBJECT (element, "set base_time=%" GST_TIME_FORMAT,
484 GST_TIME_ARGS (time));
488 * gst_element_get_base_time:
489 * @element: a #GstElement.
491 * Returns the base time of the element. The base time is the
492 * absolute time of the clock when this element was last put to
493 * PLAYING. Subtracting the base time from the clock time gives
494 * the stream time of the element.
496 * Returns: the base time of the element.
501 gst_element_get_base_time (GstElement * element)
505 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
507 GST_OBJECT_LOCK (element);
508 result = element->base_time;
509 GST_OBJECT_UNLOCK (element);
514 #ifndef GST_DISABLE_INDEX
516 * gst_element_is_indexable:
517 * @element: a #GstElement.
519 * Queries if the element can be indexed.
521 * Returns: TRUE if the element can be indexed.
526 gst_element_is_indexable (GstElement * element)
530 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
532 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
538 * gst_element_set_index:
539 * @element: a #GstElement.
540 * @index: a #GstIndex.
542 * Set @index on the element. The refcount of the index
543 * will be increased, any previously set index is unreffed.
548 gst_element_set_index (GstElement * element, GstIndex * index)
550 GstElementClass *oclass;
552 g_return_if_fail (GST_IS_ELEMENT (element));
553 g_return_if_fail (GST_IS_INDEX (index));
555 oclass = GST_ELEMENT_GET_CLASS (element);
557 if (oclass->set_index)
558 oclass->set_index (element, index);
562 * gst_element_get_index:
563 * @element: a #GstElement.
565 * Gets the index from the element.
567 * Returns: a #GstIndex or %NULL when no index was set on the
568 * element. unref after usage.
573 gst_element_get_index (GstElement * element)
575 GstElementClass *oclass;
576 GstIndex *result = NULL;
578 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
580 oclass = GST_ELEMENT_GET_CLASS (element);
582 if (oclass->get_index)
583 result = oclass->get_index (element);
590 * gst_element_add_pad:
591 * @element: a #GstElement to add the pad to.
592 * @pad: the #GstPad to add to the element.
594 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
595 * see gst_object_set_parent() for refcounting information.
597 * Pads are not automatically activated so elements should perform the needed
598 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
599 * state. See gst_pad_set_active() for more information about activating pads.
601 * The pad and the element should be unlocked when calling this function.
603 * This function will emit the #GstElement::pad-added signal on the element.
605 * Returns: %TRUE if the pad could be added. This function can fail when
606 * a pad with the same name already existed or the pad already had another
612 gst_element_add_pad (GstElement * element, GstPad * pad)
616 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
617 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
619 /* locking pad to look at the name */
620 GST_OBJECT_LOCK (pad);
621 pad_name = g_strdup (GST_PAD_NAME (pad));
622 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
623 GST_STR_NULL (pad_name));
624 GST_OBJECT_UNLOCK (pad);
626 /* then check to see if there's already a pad by that name here */
627 GST_OBJECT_LOCK (element);
628 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
631 /* try to set the pad's parent */
632 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
633 GST_OBJECT_CAST (element))))
638 /* add it to the list */
639 switch (gst_pad_get_direction (pad)) {
641 element->srcpads = g_list_prepend (element->srcpads, pad);
642 element->numsrcpads++;
645 element->sinkpads = g_list_prepend (element->sinkpads, pad);
646 element->numsinkpads++;
651 element->pads = g_list_prepend (element->pads, pad);
653 element->pads_cookie++;
654 GST_OBJECT_UNLOCK (element);
656 /* emit the PAD_ADDED signal */
657 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
664 g_critical ("Padname %s is not unique in element %s, not adding",
665 pad_name, GST_ELEMENT_NAME (element));
666 GST_OBJECT_UNLOCK (element);
673 ("Pad %s already has parent when trying to add to element %s",
674 pad_name, GST_ELEMENT_NAME (element));
675 GST_OBJECT_UNLOCK (element);
681 GST_OBJECT_LOCK (pad);
683 ("Trying to add pad %s to element %s, but it has no direction",
684 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
685 GST_OBJECT_UNLOCK (pad);
686 GST_OBJECT_UNLOCK (element);
692 * gst_element_remove_pad:
693 * @element: a #GstElement to remove pad from.
694 * @pad: the #GstPad to remove from the element.
696 * Removes @pad from @element. @pad will be destroyed if it has not been
697 * referenced elsewhere using gst_object_unparent().
699 * This function is used by plugin developers and should not be used
700 * by applications. Pads that were dynamically requested from elements
701 * with gst_element_get_request_pad() should be released with the
702 * gst_element_release_request_pad() function instead.
704 * Pads are not automatically deactivated so elements should perform the needed
705 * steps to deactivate the pad in case this pad is removed in the PAUSED or
706 * PLAYING state. See gst_pad_set_active() for more information about
709 * The pad and the element should be unlocked when calling this function.
711 * This function will emit the #GstElement::pad-removed signal on the element.
713 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
714 * pad does not belong to the provided element.
719 gst_element_remove_pad (GstElement * element, GstPad * pad)
723 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
724 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
726 /* locking pad to look at the name and parent */
727 GST_OBJECT_LOCK (pad);
728 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
729 GST_STR_NULL (GST_PAD_NAME (pad)));
731 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
733 GST_OBJECT_UNLOCK (pad);
736 if ((peer = gst_pad_get_peer (pad))) {
737 /* window for MT unsafeness, someone else could unlink here
738 * and then we call unlink with wrong pads. The unlink
739 * function would catch this and safely return failed. */
740 if (GST_PAD_IS_SRC (pad))
741 gst_pad_unlink (pad, peer);
743 gst_pad_unlink (peer, pad);
745 gst_object_unref (peer);
748 GST_OBJECT_LOCK (element);
749 /* remove it from the list */
750 switch (gst_pad_get_direction (pad)) {
752 element->srcpads = g_list_remove (element->srcpads, pad);
753 element->numsrcpads--;
756 element->sinkpads = g_list_remove (element->sinkpads, pad);
757 element->numsinkpads--;
760 g_critical ("Removing pad without direction???");
763 element->pads = g_list_remove (element->pads, pad);
765 element->pads_cookie++;
766 GST_OBJECT_UNLOCK (element);
768 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
769 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
771 gst_object_unparent (GST_OBJECT_CAST (pad));
778 /* FIXME, locking order? */
779 GST_OBJECT_LOCK (element);
780 g_critical ("Padname %s:%s does not belong to element %s when removing",
781 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
782 GST_OBJECT_UNLOCK (element);
783 GST_OBJECT_UNLOCK (pad);
789 * gst_element_no_more_pads:
790 * @element: a #GstElement
792 * Use this function to signal that the element does not expect any more pads
793 * to show up in the current pipeline. This function should be called whenever
794 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
795 * pad templates use this in combination with autopluggers to figure out that
796 * the element is done initializing its pads.
798 * This function emits the #GstElement::no-more-pads signal.
803 gst_element_no_more_pads (GstElement * element)
805 g_return_if_fail (GST_IS_ELEMENT (element));
807 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
811 pad_compare_name (GstPad * pad1, const gchar * name)
815 GST_OBJECT_LOCK (pad1);
816 result = strcmp (GST_PAD_NAME (pad1), name);
817 GST_OBJECT_UNLOCK (pad1);
823 * gst_element_get_static_pad:
824 * @element: a #GstElement to find a static pad of.
825 * @name: the name of the static #GstPad to retrieve.
827 * Retrieves a pad from @element by name. This version only retrieves
828 * already-existing (i.e. 'static') pads.
830 * Returns: the requested #GstPad if found, otherwise %NULL. unref after
836 gst_element_get_static_pad (GstElement * element, const gchar * name)
839 GstPad *result = NULL;
841 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
842 g_return_val_if_fail (name != NULL, NULL);
844 GST_OBJECT_LOCK (element);
846 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
848 result = GST_PAD_CAST (find->data);
849 gst_object_ref (result);
852 if (result == NULL) {
853 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
854 name, GST_ELEMENT_NAME (element));
856 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
857 GST_ELEMENT_NAME (element), name);
859 GST_OBJECT_UNLOCK (element);
865 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
868 GstPad *newpad = NULL;
869 GstElementClass *oclass;
871 oclass = GST_ELEMENT_GET_CLASS (element);
873 if (oclass->request_new_pad)
874 newpad = (oclass->request_new_pad) (element, templ, name);
877 gst_object_ref (newpad);
883 * gst_element_get_request_pad:
884 * @element: a #GstElement to find a request pad of.
885 * @name: the name of the request #GstPad to retrieve.
887 * Retrieves a pad from the element by name. This version only retrieves
888 * request pads. The pad should be released with
889 * gst_element_release_request_pad().
891 * Returns: requested #GstPad if found, otherwise %NULL. Release after usage.
894 gst_element_get_request_pad (GstElement * element, const gchar * name)
896 GstPadTemplate *templ = NULL;
898 const gchar *req_name = NULL;
899 gboolean templ_found = FALSE;
903 gchar *str, *endptr = NULL;
904 GstElementClass *class;
906 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
907 g_return_val_if_fail (name != NULL, NULL);
909 class = GST_ELEMENT_GET_CLASS (element);
911 if (strstr (name, "%")) {
912 templ = gst_element_class_get_pad_template (class, name);
917 list = gst_element_class_get_pad_template_list (class);
918 while (!templ_found && list) {
919 templ = (GstPadTemplate *) list->data;
920 if (templ->presence == GST_PAD_REQUEST) {
921 /* Because of sanity checks in gst_pad_template_new(), we know that %s
922 and %d, occurring at the end of the name_template, are the only
924 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
925 templ->name_template);
926 if ((str = strchr (templ->name_template, '%'))
927 && strncmp (templ->name_template, name,
928 str - templ->name_template) == 0
929 && strlen (name) > str - templ->name_template) {
930 data = name + (str - templ->name_template);
931 if (*(str + 1) == 'd') {
933 n = (gint) strtol (data, &endptr, 10);
934 if (endptr && *endptr == '\0') {
954 pad = gst_element_request_pad (element, templ, req_name);
960 * gst_element_get_pad:
961 * @element: a #GstElement.
962 * @name: the name of the pad to retrieve.
964 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
965 * first, then gst_element_get_request_pad().
967 * <note>Usage of this function is not recommended as it is unclear if the reference
968 * to the result pad should be released with gst_object_unref() in case of a static pad
969 * or gst_element_release_request_pad() in case of a request pad.</note>
971 * Returns: the #GstPad if found, otherwise %NULL. Unref or Release after usage,
972 * depending on the type of the pad.
975 gst_element_get_pad (GstElement * element, const gchar * name)
979 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
980 g_return_val_if_fail (name != NULL, NULL);
982 pad = gst_element_get_static_pad (element, name);
984 pad = gst_element_get_request_pad (element, name);
989 static GstIteratorItem
990 iterate_pad (GstIterator * it, GstPad * pad)
992 gst_object_ref (pad);
993 return GST_ITERATOR_ITEM_PASS;
997 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1001 GST_OBJECT_LOCK (element);
1002 gst_object_ref (element);
1003 result = gst_iterator_new_list (GST_TYPE_PAD,
1004 GST_OBJECT_GET_LOCK (element),
1005 &element->pads_cookie,
1008 (GstIteratorItemFunction) iterate_pad,
1009 (GstIteratorDisposeFunction) gst_object_unref);
1010 GST_OBJECT_UNLOCK (element);
1016 * gst_element_iterate_pads:
1017 * @element: a #GstElement to iterate pads of.
1019 * Retrieves an iterattor of @element's pads. The iterator should
1020 * be freed after usage.
1022 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1027 gst_element_iterate_pads (GstElement * element)
1029 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1031 return gst_element_iterate_pad_list (element, &element->pads);
1035 * gst_element_iterate_src_pads:
1036 * @element: a #GstElement.
1038 * Retrieves an iterator of @element's source pads.
1040 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1045 gst_element_iterate_src_pads (GstElement * element)
1047 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1049 return gst_element_iterate_pad_list (element, &element->srcpads);
1053 * gst_element_iterate_sink_pads:
1054 * @element: a #GstElement.
1056 * Retrieves an iterator of @element's sink pads.
1058 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1063 gst_element_iterate_sink_pads (GstElement * element)
1065 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1067 return gst_element_iterate_pad_list (element, &element->sinkpads);
1071 * gst_element_class_add_pad_template:
1072 * @klass: the #GstElementClass to add the pad template to.
1073 * @templ: a #GstPadTemplate to add to the element class.
1075 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1076 * functions of classes.
1079 gst_element_class_add_pad_template (GstElementClass * klass,
1080 GstPadTemplate * templ)
1082 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1083 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1085 /* avoid registering pad templates with the same name */
1086 g_return_if_fail (gst_element_class_get_pad_template (klass,
1087 templ->name_template) == NULL);
1089 klass->padtemplates = g_list_append (klass->padtemplates,
1090 gst_object_ref (templ));
1091 klass->numpadtemplates++;
1095 * gst_element_class_set_details:
1096 * @klass: class to set details for
1097 * @details: details to set
1099 * Sets the detailed information for a #GstElementClass.
1100 * <note>This function is for use in _base_init functions only.</note>
1102 * The @details are copied.
1105 gst_element_class_set_details (GstElementClass * klass,
1106 const GstElementDetails * details)
1108 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1109 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1111 __gst_element_details_copy (&klass->details, details);
1115 * gst_element_class_get_pad_template_list:
1116 * @element_class: a #GstElementClass to get pad templates of.
1118 * Retrieves a list of the pad templates associated with @element_class. The
1119 * list must not be modified by the calling code.
1120 * <note>If you use this function in the #GInstanceInitFunc of an object class
1121 * that has subclasses, make sure to pass the g_class parameter of the
1122 * #GInstanceInitFunc here.</note>
1124 * Returns: the #GList of padtemplates.
1127 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1129 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1131 return element_class->padtemplates;
1135 * gst_element_class_get_pad_template:
1136 * @element_class: a #GstElementClass to get the pad template of.
1137 * @name: the name of the #GstPadTemplate to get.
1139 * Retrieves a padtemplate from @element_class with the given name.
1140 * <note>If you use this function in the #GInstanceInitFunc of an object class
1141 * that has subclasses, make sure to pass the g_class parameter of the
1142 * #GInstanceInitFunc here.</note>
1144 * Returns: the #GstPadTemplate with the given name, or %NULL if none was found.
1145 * No unreferencing is necessary.
1148 gst_element_class_get_pad_template (GstElementClass * element_class,
1153 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1154 g_return_val_if_fail (name != NULL, NULL);
1156 padlist = gst_element_class_get_pad_template_list (element_class);
1159 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1161 if (strcmp (padtempl->name_template, name) == 0)
1164 padlist = g_list_next (padlist);
1170 /* get a random pad on element of the given direction.
1171 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1174 gst_element_get_random_pad (GstElement * element, gboolean need_linked,
1175 GstPadDirection dir)
1177 GstPad *result = NULL;
1180 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1184 GST_OBJECT_LOCK (element);
1185 pads = element->srcpads;
1188 GST_OBJECT_LOCK (element);
1189 pads = element->sinkpads;
1192 goto wrong_direction;
1194 for (; pads; pads = g_list_next (pads)) {
1195 GstPad *pad = GST_PAD_CAST (pads->data);
1197 GST_OBJECT_LOCK (pad);
1198 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1199 GST_DEBUG_PAD_NAME (pad));
1201 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1202 /* if we require a linked pad, and it is not linked, continue the
1204 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1205 GST_DEBUG_PAD_NAME (pad));
1206 GST_OBJECT_UNLOCK (pad);
1209 /* found a pad, stop search */
1210 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1211 GST_DEBUG_PAD_NAME (pad));
1212 GST_OBJECT_UNLOCK (pad);
1218 gst_object_ref (result);
1220 GST_OBJECT_UNLOCK (element);
1224 /* ERROR handling */
1227 g_warning ("unknown pad direction %d", dir);
1233 gst_element_default_send_event (GstElement * element, GstEvent * event)
1235 gboolean result = FALSE;
1238 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1239 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1240 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1243 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1244 "pushing %s event to random %s pad %s:%s",
1245 GST_EVENT_TYPE_NAME (event),
1246 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1247 GST_DEBUG_PAD_NAME (pad));
1249 result = gst_pad_push_event (pad, event);
1250 gst_object_unref (pad);
1252 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1253 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1259 * gst_element_send_event:
1260 * @element: a #GstElement to send the event to.
1261 * @event: the #GstEvent to send to the element.
1263 * Sends an event to an element. If the element doesn't implement an
1264 * event handler, the event will be pushed on a random linked sink pad for
1265 * upstream events or a random linked source pad for downstream events.
1267 * This function takes owership of the provided event so you should
1268 * gst_event_ref() it if you want to reuse the event after this call.
1270 * Returns: %TRUE if the event was handled.
1275 gst_element_send_event (GstElement * element, GstEvent * event)
1277 GstElementClass *oclass;
1278 gboolean result = FALSE;
1280 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1281 g_return_val_if_fail (event != NULL, FALSE);
1283 oclass = GST_ELEMENT_GET_CLASS (element);
1285 if (oclass->send_event) {
1286 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send %s event on element %s",
1287 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1288 result = oclass->send_event (element, event);
1290 result = gst_element_default_send_event (element, event);
1297 * @element: a #GstElement to send the event to.
1298 * @rate: The new playback rate
1299 * @format: The format of the seek values
1300 * @flags: The optional seek flags.
1301 * @cur_type: The type and flags for the new current position
1302 * @cur: The value of the new current position
1303 * @stop_type: The type and flags for the new stop position
1304 * @stop: The value of the new stop position
1306 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1307 * the parameters. The seek event is sent to the element using
1308 * gst_element_send_event().
1310 * Returns: %TRUE if the event was handled.
1315 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1316 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1317 GstSeekType stop_type, gint64 stop)
1322 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1325 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1326 result = gst_element_send_event (element, event);
1332 * gst_element_get_query_types:
1333 * @element: a #GstElement to query
1335 * Get an array of query types from the element.
1336 * If the element doesn't implement a query types function,
1337 * the query will be forwarded to the peer of a random linked sink pad.
1339 * Returns: An array of #GstQueryType elements that should not
1340 * be freed or modified.
1344 const GstQueryType *
1345 gst_element_get_query_types (GstElement * element)
1347 GstElementClass *oclass;
1348 const GstQueryType *result = NULL;
1350 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1352 oclass = GST_ELEMENT_GET_CLASS (element);
1354 if (oclass->get_query_types) {
1355 result = oclass->get_query_types (element);
1357 GstPad *pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1360 GstPad *peer = gst_pad_get_peer (pad);
1363 result = gst_pad_get_query_types (peer);
1365 gst_object_unref (peer);
1367 gst_object_unref (pad);
1374 gst_element_default_query (GstElement * element, GstQuery * query)
1376 gboolean result = FALSE;
1379 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1381 result = gst_pad_query (pad, query);
1383 gst_object_unref (pad);
1385 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1387 GstPad *peer = gst_pad_get_peer (pad);
1390 result = gst_pad_query (peer, query);
1392 gst_object_unref (peer);
1394 gst_object_unref (pad);
1401 * gst_element_query:
1402 * @element: a #GstElement to perform the query on.
1403 * @query: the #GstQuery.
1405 * Performs a query on the given element.
1407 * For elements that don't implement a query handler, this function
1408 * forwards the query to a random srcpad or to the peer of a
1409 * random linked sinkpad of this element.
1411 * Returns: TRUE if the query could be performed.
1416 gst_element_query (GstElement * element, GstQuery * query)
1418 GstElementClass *oclass;
1419 gboolean result = FALSE;
1421 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1422 g_return_val_if_fail (query != NULL, FALSE);
1424 oclass = GST_ELEMENT_GET_CLASS (element);
1426 if (oclass->query) {
1427 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1428 GST_ELEMENT_NAME (element));
1429 result = oclass->query (element, query);
1431 result = gst_element_default_query (element, query);
1437 * gst_element_post_message:
1438 * @element: a #GstElement posting the message
1439 * @message: a #GstMessage to post
1441 * Post a message on the element's #GstBus. This function takes ownership of the
1442 * message; if you want to access the message after this call, you should add an
1443 * additional reference before calling.
1445 * Returns: %TRUE if the message was successfully posted. The function returns
1446 * %FALSE if the element did not have a bus.
1451 gst_element_post_message (GstElement * element, GstMessage * message)
1454 gboolean result = FALSE;
1456 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1457 g_return_val_if_fail (message != NULL, FALSE);
1459 GST_OBJECT_LOCK (element);
1462 if (G_UNLIKELY (bus == NULL))
1465 gst_object_ref (bus);
1466 GST_OBJECT_UNLOCK (element);
1468 /* we release the element lock when posting the message so that any
1469 * (synchronous) message handlers can operate on the element */
1470 result = gst_bus_post (bus, message);
1471 gst_object_unref (bus);
1478 GST_DEBUG_OBJECT (element, "not posting message %p: no bus", message);
1479 GST_OBJECT_UNLOCK (element);
1480 gst_message_unref (message);
1486 * _gst_element_error_printf:
1487 * @format: the printf-like format to use, or %NULL
1489 * This function is only used internally by the gst_element_error() macro.
1491 * Returns: a newly allocated string, or %NULL if the format was %NULL or ""
1496 _gst_element_error_printf (const gchar * format, ...)
1506 va_start (args, format);
1507 buffer = g_strdup_vprintf (format, args);
1513 * gst_element_message_full:
1514 * @element: a #GstElement to send message from
1515 * @type: the #GstMessageType
1516 * @domain: the GStreamer GError domain this message belongs to
1517 * @code: the GError code belonging to the domain
1518 * @text: an allocated text string to be used as a replacement for the
1519 * default message connected to code, or %NULL
1520 * @debug: an allocated debug message to be used as a replacement for the
1521 * default debugging information, or %NULL
1522 * @file: the source code file where the error was generated
1523 * @function: the source code function where the error was generated
1524 * @line: the source code line where the error was generated
1526 * Post an error or warning message on the bus from inside an element.
1530 void gst_element_message_full
1531 (GstElement * element, GstMessageType type,
1532 GQuark domain, gint code, gchar * text,
1533 gchar * debug, const gchar * file, const gchar * function, gint line)
1535 GError *gerror = NULL;
1539 gboolean has_debug = TRUE;
1540 GstMessage *message = NULL;
1543 GST_DEBUG_OBJECT (element, "start");
1544 g_return_if_fail (GST_IS_ELEMENT (element));
1545 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1546 (type == GST_MESSAGE_WARNING));
1548 /* check if we send the given text or the default error text */
1549 if ((text == NULL) || (text[0] == 0)) {
1550 /* text could have come from g_strdup_printf (""); */
1552 sent_text = gst_error_get_message (domain, code);
1556 /* construct a sent_debug with extra information from source */
1557 if ((debug == NULL) || (debug[0] == 0)) {
1558 /* debug could have come from g_strdup_printf (""); */
1562 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1564 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1565 file, line, function, name, debug);
1567 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1568 file, line, function, name);
1572 /* create gerror and post message */
1573 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1575 gerror = g_error_new_literal (domain, code, sent_text);
1577 if (type == GST_MESSAGE_ERROR) {
1579 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1580 } else if (type == GST_MESSAGE_WARNING) {
1581 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1584 g_assert_not_reached ();
1586 gst_element_post_message (element, message);
1588 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1589 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1592 g_error_free (gerror);
1593 g_free (sent_debug);
1598 * gst_element_is_locked_state:
1599 * @element: a #GstElement.
1601 * Checks if the state of an element is locked.
1602 * If the state of an element is locked, state changes of the parent don't
1603 * affect the element.
1604 * This way you can leave currently unused elements inside bins. Just lock their
1605 * state before changing the state from #GST_STATE_NULL.
1609 * Returns: TRUE, if the element's state is locked.
1612 gst_element_is_locked_state (GstElement * element)
1616 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1618 GST_OBJECT_LOCK (element);
1619 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1620 GST_OBJECT_UNLOCK (element);
1626 * gst_element_set_locked_state:
1627 * @element: a #GstElement
1628 * @locked_state: TRUE to lock the element's state
1630 * Locks the state of an element, so state changes of the parent don't affect
1631 * this element anymore.
1635 * Returns: TRUE if the state was changed, FALSE if bad parameterss were given
1636 * or the elements state-locking needed no change.
1639 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1643 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1645 GST_OBJECT_LOCK (element);
1646 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1648 if (G_UNLIKELY (old == locked_state))
1652 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1653 GST_ELEMENT_NAME (element));
1654 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1656 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1657 GST_ELEMENT_NAME (element));
1658 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1660 GST_OBJECT_UNLOCK (element);
1665 GST_CAT_DEBUG (GST_CAT_STATES, "elements %s was in locked state %d",
1666 GST_ELEMENT_NAME (element), old);
1667 GST_OBJECT_UNLOCK (element);
1673 * gst_element_sync_state_with_parent:
1674 * @element: a #GstElement.
1676 * Tries to change the state of the element to the same as its parent.
1677 * If this function returns FALSE, the state of element is undefined.
1679 * Returns: TRUE, if the element's state could be synced to the parent's state.
1684 gst_element_sync_state_with_parent (GstElement * element)
1688 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1690 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1691 GstState parent_current, parent_pending;
1692 GstStateChangeReturn ret;
1694 GST_OBJECT_LOCK (parent);
1695 parent_current = GST_STATE (parent);
1696 parent_pending = GST_STATE_PENDING (parent);
1697 GST_OBJECT_UNLOCK (parent);
1699 GST_CAT_DEBUG (GST_CAT_STATES,
1700 "syncing state of element %s (%s) to %s (%s, %s)",
1701 GST_ELEMENT_NAME (element),
1702 gst_element_state_get_name (GST_STATE (element)),
1703 GST_ELEMENT_NAME (parent), gst_element_state_get_name (parent_current),
1704 gst_element_state_get_name (parent_pending));
1706 ret = gst_element_set_state (element, parent_current);
1707 if (ret == GST_STATE_CHANGE_FAILURE)
1710 gst_object_unref (parent);
1724 static GstStateChangeReturn
1725 gst_element_get_state_func (GstElement * element,
1726 GstState * state, GstState * pending, GstClockTime timeout)
1728 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1729 GstState old_pending;
1731 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state");
1733 GST_OBJECT_LOCK (element);
1734 ret = GST_STATE_RETURN (element);
1736 /* we got an error, report immediatly */
1737 if (ret == GST_STATE_CHANGE_FAILURE)
1740 /* we got no_preroll, report immediatly */
1741 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1744 /* no need to wait async if we are not async */
1745 if (ret != GST_STATE_CHANGE_ASYNC)
1748 old_pending = GST_STATE_PENDING (element);
1749 if (old_pending != GST_STATE_VOID_PENDING) {
1750 GTimeVal *timeval, abstimeout;
1753 if (timeout != GST_CLOCK_TIME_NONE) {
1754 glong add = timeout / 1000;
1759 /* make timeout absolute */
1760 g_get_current_time (&abstimeout);
1761 g_time_val_add (&abstimeout, add);
1762 timeval = &abstimeout;
1766 /* get cookie to dected state change during waiting */
1767 cookie = element->state_cookie;
1769 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1770 "waiting for element to commit state");
1772 /* we have a pending state change, wait for it to complete */
1773 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1774 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1775 /* timeout triggered */
1776 ret = GST_STATE_CHANGE_ASYNC;
1778 if (cookie != element->state_cookie)
1781 /* could be success or failure */
1782 if (old_pending == GST_STATE (element)) {
1783 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1784 ret = GST_STATE_CHANGE_SUCCESS;
1786 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1787 ret = GST_STATE_CHANGE_FAILURE;
1791 /* if nothing is pending anymore we can return SUCCESS */
1792 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1793 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1794 ret = GST_STATE_CHANGE_SUCCESS;
1799 *state = GST_STATE (element);
1801 *pending = GST_STATE_PENDING (element);
1803 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1804 "state current: %s, pending: %s, result: %s",
1805 gst_element_state_get_name (GST_STATE (element)),
1806 gst_element_state_get_name (GST_STATE_PENDING (element)),
1807 gst_element_state_change_return_get_name (ret));
1808 GST_OBJECT_UNLOCK (element);
1815 *state = GST_STATE_VOID_PENDING;
1817 *pending = GST_STATE_VOID_PENDING;
1819 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "get_state() interruped");
1821 GST_OBJECT_UNLOCK (element);
1823 return GST_STATE_CHANGE_FAILURE;
1828 * gst_element_get_state:
1829 * @element: a #GstElement to get the state of.
1830 * @state: a pointer to #GstState to hold the state. Can be %NULL.
1831 * @pending: a pointer to #GstState to hold the pending state.
1833 * @timeout: a #GstClockTime to specify the timeout for an async
1834 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
1836 * Gets the state of the element.
1838 * For elements that performed an ASYNC state change, as reported by
1839 * gst_element_set_state(), this function will block up to the
1840 * specified timeout value for the state change to complete.
1841 * If the element completes the state change or goes into
1842 * an error, this function returns immediately with a return value of
1843 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
1845 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
1846 * returns the current and pending state immediately.
1848 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
1849 * successfully changed its state but is not able to provide data yet.
1851 * happens for live sources that only produce data in the PLAYING state.
1852 * While the state change return is equivalent to %GST_STATE_CHANGE_SUCCESS, it
1853 * is returned to the application to signal that some sink elements might not
1854 * be able to complete their state change because an element is not producing
1855 * data to complete the preroll. When setting the element to playing,
1856 * the preroll will complete and playback will start.
1858 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
1859 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
1860 * element is still performing a state change or
1861 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
1865 GstStateChangeReturn
1866 gst_element_get_state (GstElement * element,
1867 GstState * state, GstState * pending, GstClockTime timeout)
1869 GstElementClass *oclass;
1870 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
1872 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
1874 oclass = GST_ELEMENT_GET_CLASS (element);
1876 if (oclass->get_state)
1877 result = (oclass->get_state) (element, state, pending, timeout);
1883 * gst_element_abort_state:
1884 * @element: a #GstElement to abort the state of.
1886 * Abort the state change of the element. This function is used
1887 * by elements that do asynchronous state changes and find out
1888 * something is wrong.
1890 * This function should be called with the STATE_LOCK held.
1895 gst_element_abort_state (GstElement * element)
1899 #ifndef GST_DISABLE_GST_DEBUG
1903 g_return_if_fail (GST_IS_ELEMENT (element));
1905 GST_OBJECT_LOCK (element);
1906 pending = GST_STATE_PENDING (element);
1908 if (pending == GST_STATE_VOID_PENDING ||
1909 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
1910 goto nothing_aborted;
1912 #ifndef GST_DISABLE_GST_DEBUG
1913 old_state = GST_STATE (element);
1915 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1916 "aborting state from %s to %s", gst_element_state_get_name (old_state),
1917 gst_element_state_get_name (pending));
1921 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
1923 GST_STATE_BROADCAST (element);
1924 GST_OBJECT_UNLOCK (element);
1930 GST_OBJECT_UNLOCK (element);
1936 * gst_element_continue_state:
1937 * @element: a #GstElement to continue the state change of.
1938 * @ret: The previous state return value
1940 * Commit the state change of the element and proceed to the next
1941 * pending state if any. This function is used
1942 * by elements that do asynchronous state changes.
1943 * The core will normally call this method automatically when an
1944 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
1945 * Elements that return %GST_STATE_CHANGE_ASYNC from the change_state function
1946 * should eventually call this method from the streaming thread to signal
1947 * successfull state change completion.
1949 * If after calling this method the element still has not reached
1950 * the pending state, the next state change is performed.
1952 * Returns: The result of the commit state change.
1956 GstStateChangeReturn
1957 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
1960 GstState old_ret, old_state, old_next;
1961 GstState current, next;
1962 GstMessage *message;
1963 GstStateChange transition;
1965 GST_OBJECT_LOCK (element);
1966 old_ret = (GstState) GST_STATE_RETURN (element);
1967 GST_STATE_RETURN (element) = ret;
1968 pending = GST_STATE_PENDING (element);
1970 /* check if there is something to commit */
1971 if (pending == GST_STATE_VOID_PENDING)
1972 goto nothing_pending;
1974 old_state = GST_STATE (element);
1975 /* this is the state we should go to next */
1976 old_next = GST_STATE_NEXT (element);
1977 /* update current state */
1978 current = GST_STATE (element) = old_next;
1980 /* see if we reached the final state */
1981 if (pending == current)
1984 next = GST_STATE_GET_NEXT (current, pending);
1985 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
1987 GST_STATE_NEXT (element) = next;
1989 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
1990 GST_OBJECT_UNLOCK (element);
1992 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1993 "committing state from %s to %s, pending %s",
1994 gst_element_state_get_name (old_state),
1995 gst_element_state_get_name (old_next),
1996 gst_element_state_get_name (pending));
1998 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
1999 old_state, old_next, pending);
2000 gst_element_post_message (element, message);
2002 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2003 "continue state change %s to %s, final %s",
2004 gst_element_state_get_name (current),
2005 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2007 ret = gst_element_change_state (element, transition);
2013 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2014 GST_OBJECT_UNLOCK (element);
2019 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2020 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2022 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "completed state change");
2023 GST_OBJECT_UNLOCK (element);
2025 /* don't post silly messages with the same state. This can happen
2026 * when an element state is changed to what it already was. For bins
2027 * this can be the result of a lost state, which we check with the
2028 * previous return value.
2029 * We do signal the cond though as a _get_state() might be blocking
2031 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC) {
2032 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2033 old_state, old_next, GST_STATE_VOID_PENDING);
2034 gst_element_post_message (element, message);
2037 GST_STATE_BROADCAST (element);
2044 * gst_element_lost_state:
2045 * @element: a #GstElement the state is lost of
2047 * Brings the element to the lost state. The current state of the
2048 * element is copied to the pending state so that any call to
2049 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2051 * This is mostly used for elements that lost their preroll buffer
2052 * in the %GST_STATE_PAUSED state after a flush, they become %GST_STATE_PAUSED
2053 * again if a new preroll buffer is queued.
2054 * This function can only be called when the element is currently
2055 * not in error or an async state change.
2057 * This function can only be called with the STATE_LOCK held.
2062 gst_element_lost_state (GstElement * element)
2064 GstState current_state;
2065 GstMessage *message;
2067 g_return_if_fail (GST_IS_ELEMENT (element));
2069 GST_OBJECT_LOCK (element);
2070 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING ||
2071 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2074 current_state = GST_STATE (element);
2076 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2077 "lost state of %s", gst_element_state_get_name (current_state));
2079 GST_STATE_NEXT (element) = current_state;
2080 GST_STATE_PENDING (element) = current_state;
2081 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2082 GST_OBJECT_UNLOCK (element);
2084 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2085 current_state, current_state, current_state);
2086 gst_element_post_message (element, message);
2088 /* and mark us dirty */
2089 message = gst_message_new_state_dirty (GST_OBJECT_CAST (element));
2090 gst_element_post_message (element, message);
2096 GST_OBJECT_UNLOCK (element);
2102 * gst_element_set_state:
2103 * @element: a #GstElement to change state of.
2104 * @state: the element's new #GstState.
2106 * Sets the state of the element. This function will try to set the
2107 * requested state by going through all the intermediary states and calling
2108 * the class's state change function for each.
2110 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2111 * element will perform the remainder of the state change asynchronously in
2113 * An application can use gst_element_get_state() to wait for the completion
2114 * of the state change or it can wait for a state change message on the bus.
2116 * Returns: Result of the state change using #GstStateChangeReturn.
2120 GstStateChangeReturn
2121 gst_element_set_state (GstElement * element, GstState state)
2123 GstElementClass *oclass;
2124 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2126 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2128 oclass = GST_ELEMENT_GET_CLASS (element);
2130 if (oclass->set_state)
2131 result = (oclass->set_state) (element, state);
2137 * default set state function, calculates the next state based
2138 * on current state and calls the change_state function
2140 static GstStateChangeReturn
2141 gst_element_set_state_func (GstElement * element, GstState state)
2143 GstState current, next, old_pending;
2144 GstStateChangeReturn ret;
2145 GstStateChange transition;
2146 GstStateChangeReturn old_ret;
2148 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2150 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2151 gst_element_state_get_name (state));
2153 /* state lock is taken to protect the set_state() and get_state()
2154 * procedures, it does not lock any variables. */
2155 GST_STATE_LOCK (element);
2157 /* now calculate how to get to the new state */
2158 GST_OBJECT_LOCK (element);
2159 old_ret = GST_STATE_RETURN (element);
2160 /* previous state change returned an error, remove all pending
2161 * and next states */
2162 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2163 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2164 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2165 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2168 current = GST_STATE (element);
2169 next = GST_STATE_NEXT (element);
2170 old_pending = GST_STATE_PENDING (element);
2171 /* increment state cookie so that we can track each state change */
2172 element->state_cookie++;
2174 /* this is the (new) state we should go to */
2175 GST_STATE_PENDING (element) = state;
2177 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2178 "current %s, old_pending %s, next %s, old return %s",
2179 gst_element_state_get_name (current),
2180 gst_element_state_get_name (old_pending),
2181 gst_element_state_get_name (next),
2182 gst_element_state_change_return_get_name (old_ret));
2184 /* if the element was busy doing a state change, we just update the
2185 * target state, it'll get to it async then. */
2186 if (old_pending != GST_STATE_VOID_PENDING) {
2187 /* upwards state change will happen ASYNC */
2188 if (old_pending <= state)
2190 /* element is going to this state already */
2191 else if (next == state)
2193 /* element was performing an ASYNC upward state change and
2194 * we request to go downward again. Start from the next pending
2196 else if (next > state
2197 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2201 next = GST_STATE_GET_NEXT (current, state);
2202 /* now we store the next state */
2203 GST_STATE_NEXT (element) = next;
2204 /* mark busy, we need to check that there is actually a state change
2205 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2206 * the default element change_state function has no way to know what the
2207 * old value was... could consider this a FIXME...*/
2208 if (current != next)
2209 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2211 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2213 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2214 "%s: setting state from %s to %s",
2215 (next != state ? "intermediate" : "final"),
2216 gst_element_state_get_name (current), gst_element_state_get_name (next));
2218 /* now signal any waiters, they will error since the cookie was increased */
2219 GST_STATE_BROADCAST (element);
2221 GST_OBJECT_UNLOCK (element);
2223 ret = gst_element_change_state (element, transition);
2225 GST_STATE_UNLOCK (element);
2227 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2228 gst_element_state_change_return_get_name (ret));
2234 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2235 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2236 "element was busy with async state change");
2237 GST_OBJECT_UNLOCK (element);
2239 GST_STATE_UNLOCK (element);
2241 return GST_STATE_CHANGE_ASYNC;
2245 /* with STATE_LOCK */
2246 static GstStateChangeReturn
2247 gst_element_change_state (GstElement * element, GstStateChange transition)
2249 GstElementClass *oclass;
2250 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2254 oclass = GST_ELEMENT_GET_CLASS (element);
2256 /* start with the current state. */
2257 current = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2258 next = GST_STATE_TRANSITION_NEXT (transition);
2260 /* call the state change function so it can set the state */
2261 if (oclass->change_state)
2262 ret = (oclass->change_state) (element, transition);
2264 ret = GST_STATE_CHANGE_FAILURE;
2267 case GST_STATE_CHANGE_FAILURE:
2268 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2269 "have FAILURE change_state return");
2270 /* state change failure */
2271 gst_element_abort_state (element);
2273 case GST_STATE_CHANGE_ASYNC:
2274 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2275 "element will change state ASYNC");
2277 /* if we go upwards, we give the app a change to wait for
2282 /* else we just continue the state change downwards */
2283 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2284 "forcing commit state %s < %s",
2285 gst_element_state_get_name (current),
2286 gst_element_state_get_name (next));
2288 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2290 case GST_STATE_CHANGE_SUCCESS:
2291 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2292 "element changed state SUCCESS");
2293 /* we can commit the state now which will proceeed to
2295 ret = gst_element_continue_state (element, ret);
2297 case GST_STATE_CHANGE_NO_PREROLL:
2298 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2299 "element changed state NO_PREROLL");
2300 /* we can commit the state now which will proceeed to
2302 ret = gst_element_continue_state (element, ret);
2305 goto invalid_return;
2308 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2313 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2321 GST_OBJECT_LOCK (element);
2322 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2323 g_critical ("%s: unknown return value %d from a state change function",
2324 GST_ELEMENT_NAME (element), ret);
2326 ret = GST_STATE_CHANGE_FAILURE;
2327 GST_STATE_RETURN (element) = ret;
2328 GST_OBJECT_UNLOCK (element);
2334 /* gst_iterator_fold functions for pads_activate
2335 * Note how we don't stop the iterator when we fail an activation. This is
2336 * probably a FIXME since when one pad activation fails, we don't want to
2337 * continue our state change. */
2339 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2341 if (!gst_pad_set_active (pad, *active))
2342 g_value_set_boolean (ret, FALSE);
2344 /* unref the object that was reffed for us by _fold */
2345 gst_object_unref (pad);
2349 /* set the caps on the pad to NULL */
2351 clear_caps (GstPad * pad, GValue * ret, gboolean * active)
2353 gst_pad_set_caps (pad, NULL);
2354 gst_object_unref (pad);
2358 /* returns false on error or early cutout (will never happen because the fold
2359 * function always returns TRUE, see FIXME above) of the fold, true if all
2360 * pads in @iter were (de)activated successfully. */
2362 iterator_activate_fold_with_resync (GstIterator * iter,
2363 GstIteratorFoldFunction func, gpointer user_data)
2365 GstIteratorResult ires;
2368 /* no need to unset this later, it's just a boolean */
2369 g_value_init (&ret, G_TYPE_BOOLEAN);
2370 g_value_set_boolean (&ret, TRUE);
2373 ires = gst_iterator_fold (iter, func, &ret, user_data);
2375 case GST_ITERATOR_RESYNC:
2376 /* need to reset the result again */
2377 g_value_set_boolean (&ret, TRUE);
2378 gst_iterator_resync (iter);
2380 case GST_ITERATOR_DONE:
2381 /* all pads iterated, return collected value */
2384 /* iterator returned _ERROR or premature end with _OK,
2385 * mark an error and exit */
2386 g_value_set_boolean (&ret, FALSE);
2391 /* return collected value */
2392 return g_value_get_boolean (&ret);
2395 /* is called with STATE_LOCK
2397 * Pads are activated from source pads to sinkpads.
2400 gst_element_pads_activate (GstElement * element, gboolean active)
2405 GST_DEBUG_OBJECT (element, "pads_activate with active %d", active);
2407 iter = gst_element_iterate_src_pads (element);
2409 iterator_activate_fold_with_resync (iter,
2410 (GstIteratorFoldFunction) activate_pads, &active);
2411 gst_iterator_free (iter);
2412 if (G_UNLIKELY (!res))
2415 iter = gst_element_iterate_sink_pads (element);
2417 iterator_activate_fold_with_resync (iter,
2418 (GstIteratorFoldFunction) activate_pads, &active);
2419 gst_iterator_free (iter);
2420 if (G_UNLIKELY (!res))
2424 /* clear the caps on all pads, this should never fail */
2425 iter = gst_element_iterate_pads (element);
2427 iterator_activate_fold_with_resync (iter,
2428 (GstIteratorFoldFunction) clear_caps, &active);
2429 gst_iterator_free (iter);
2430 if (G_UNLIKELY (!res))
2434 GST_DEBUG_OBJECT (element, "pads_activate successful");
2441 GST_DEBUG_OBJECT (element, "source pads_activate failed");
2446 GST_DEBUG_OBJECT (element, "sink pads_activate failed");
2451 GST_DEBUG_OBJECT (element, "failed to clear caps on pads");
2456 /* is called with STATE_LOCK */
2457 static GstStateChangeReturn
2458 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2460 GstState state, next;
2461 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2463 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2465 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2466 next = GST_STATE_TRANSITION_NEXT (transition);
2468 /* if the element already is in the given state, we just return success */
2469 if (next == GST_STATE_VOID_PENDING || state == next)
2472 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2473 "default handler tries setting state from %s to %s (%04x)",
2474 gst_element_state_get_name (state),
2475 gst_element_state_get_name (next), transition);
2477 switch (transition) {
2478 case GST_STATE_CHANGE_NULL_TO_READY:
2480 case GST_STATE_CHANGE_READY_TO_PAUSED:
2481 if (!gst_element_pads_activate (element, TRUE)) {
2482 result = GST_STATE_CHANGE_FAILURE;
2485 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2487 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2489 case GST_STATE_CHANGE_PAUSED_TO_READY:
2490 case GST_STATE_CHANGE_READY_TO_NULL:
2491 /* deactivate pads in both cases, since they are activated on
2492 ready->paused but the element might not have made it to paused */
2493 if (!gst_element_pads_activate (element, FALSE)) {
2494 result = GST_STATE_CHANGE_FAILURE;
2496 gst_element_set_base_time (element, 0);
2500 /* this will catch real but unhandled state changes;
2501 * can only be caused by:
2502 * - a new state was added
2503 * - somehow the element was asked to jump across an intermediate state
2505 g_warning ("Unhandled state change from %s to %s",
2506 gst_element_state_get_name (state),
2507 gst_element_state_get_name (next));
2514 GST_OBJECT_LOCK (element);
2515 result = GST_STATE_RETURN (element);
2516 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2517 "element is already in the %s state",
2518 gst_element_state_get_name (state));
2519 GST_OBJECT_UNLOCK (element);
2526 * gst_element_get_factory:
2527 * @element: a #GstElement to request the element factory of.
2529 * Retrieves the factory that was used to create this element.
2531 * Returns: the #GstElementFactory used for creating this element.
2532 * no refcounting is needed.
2535 gst_element_get_factory (GstElement * element)
2537 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2539 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2543 gst_element_dispose (GObject * object)
2545 GstElement *element = GST_ELEMENT (object);
2549 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2551 if (GST_STATE (element) != GST_STATE_NULL)
2554 g_return_if_fail (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING);
2556 GST_DEBUG_OBJECT (element, "removing %d pads", g_list_length (element->pads));
2557 /* first we break all our links with the outside */
2558 while (element->pads && element->pads->data) {
2559 /* don't call _remove_pad with NULL */
2560 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2562 if (G_UNLIKELY (element->pads != 0)) {
2563 g_critical ("could not remove pads from element %s",
2564 GST_STR_NULL (GST_OBJECT_NAME (object)));
2567 GST_OBJECT_LOCK (element);
2568 clock_p = &element->clock;
2569 bus_p = &element->bus;
2570 gst_object_replace ((GstObject **) clock_p, NULL);
2571 gst_object_replace ((GstObject **) bus_p, NULL);
2572 GST_OBJECT_UNLOCK (element);
2574 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2576 G_OBJECT_CLASS (parent_class)->dispose (object);
2584 ("\nTrying to dispose element %s, but it is not in the NULL state.\n"
2585 "You need to explicitly set elements to the NULL state before\n"
2586 "dropping the final reference, to allow them to clean up.\n",
2587 GST_OBJECT_NAME (element));
2593 gst_element_finalize (GObject * object)
2595 GstElement *element = GST_ELEMENT (object);
2597 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2599 GST_STATE_LOCK (element);
2600 if (element->state_cond)
2601 g_cond_free (element->state_cond);
2602 element->state_cond = NULL;
2603 GST_STATE_UNLOCK (element);
2604 g_static_rec_mutex_free (element->state_lock);
2605 g_free (element->state_lock);
2606 element->state_lock = NULL;
2608 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2610 G_OBJECT_CLASS (parent_class)->finalize (object);
2613 #ifndef GST_DISABLE_LOADSAVE
2615 * gst_element_save_thyself:
2616 * @element: a #GstElement to save.
2617 * @parent: the xml parent node.
2619 * Saves the element as part of the given XML structure.
2621 * Returns: the new #xmlNodePtr.
2624 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2627 GstElementClass *oclass;
2628 GParamSpec **specs, *spec;
2631 GValue value = { 0, };
2632 GstElement *element;
2634 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2636 element = GST_ELEMENT (object);
2638 oclass = GST_ELEMENT_GET_CLASS (element);
2640 xmlNewChild (parent, NULL, (xmlChar *) "name",
2641 (xmlChar *) GST_ELEMENT_NAME (element));
2643 if (oclass->elementfactory != NULL) {
2644 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2646 xmlNewChild (parent, NULL, (xmlChar *) "type",
2647 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2651 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2653 for (i = 0; i < nspecs; i++) {
2655 if (spec->flags & G_PARAM_READABLE) {
2659 g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (spec));
2661 g_object_get_property (G_OBJECT (element), spec->name, &value);
2662 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2663 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2665 if (G_IS_PARAM_SPEC_STRING (spec))
2666 contents = g_value_dup_string (&value);
2667 else if (G_IS_PARAM_SPEC_ENUM (spec))
2668 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2669 else if (G_IS_PARAM_SPEC_INT64 (spec))
2670 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2671 g_value_get_int64 (&value));
2673 contents = g_strdup_value_contents (&value);
2675 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2678 g_value_unset (&value);
2684 pads = GST_ELEMENT_PADS (element);
2687 GstPad *pad = GST_PAD_CAST (pads->data);
2689 /* figure out if it's a direct pad or a ghostpad */
2690 if (GST_ELEMENT (GST_OBJECT_PARENT (pad)) == element) {
2691 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
2693 gst_object_save_thyself (GST_OBJECT_CAST (pad), padtag);
2695 pads = g_list_next (pads);
2702 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
2704 xmlNodePtr children;
2705 GstElement *element;
2707 gchar *value = NULL;
2709 element = GST_ELEMENT (object);
2710 g_return_if_fail (element != NULL);
2713 children = self->xmlChildrenNode;
2715 if (!strcmp ((char *) children->name, "param")) {
2716 xmlNodePtr child = children->xmlChildrenNode;
2719 if (!strcmp ((char *) child->name, "name")) {
2720 name = (gchar *) xmlNodeGetContent (child);
2721 } else if (!strcmp ((char *) child->name, "value")) {
2722 value = (gchar *) xmlNodeGetContent (child);
2724 child = child->next;
2726 /* FIXME: can this just be g_object_set ? */
2727 gst_util_set_object_arg (G_OBJECT (element), name, value);
2728 /* g_object_set (G_OBJECT (element), name, value, NULL); */
2732 children = children->next;
2736 children = self->xmlChildrenNode;
2738 if (!strcmp ((char *) children->name, "pad")) {
2739 gst_pad_load_and_link (children, GST_OBJECT_CAST (element));
2741 children = children->next;
2744 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
2745 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
2747 #endif /* GST_DISABLE_LOADSAVE */
2750 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2754 g_return_if_fail (GST_IS_ELEMENT (element));
2756 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2758 GST_OBJECT_LOCK (element);
2759 bus_p = &GST_ELEMENT_BUS (element);
2760 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2761 GST_OBJECT_UNLOCK (element);
2765 * gst_element_set_bus:
2766 * @element: a #GstElement to set the bus of.
2767 * @bus: the #GstBus to set.
2769 * Sets the bus of the element. Increases the refcount on the bus.
2770 * For internal use only, unless you're testing elements.
2775 gst_element_set_bus (GstElement * element, GstBus * bus)
2777 GstElementClass *oclass;
2779 g_return_if_fail (GST_IS_ELEMENT (element));
2781 oclass = GST_ELEMENT_GET_CLASS (element);
2783 if (oclass->set_bus)
2784 oclass->set_bus (element, bus);
2788 * gst_element_get_bus:
2789 * @element: a #GstElement to get the bus of.
2791 * Returns the bus of the element.
2793 * Returns: the element's #GstBus. unref after usage.
2798 gst_element_get_bus (GstElement * element)
2800 GstBus *result = NULL;
2802 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2804 GST_OBJECT_LOCK (element);
2805 if ((result = GST_ELEMENT_BUS (element)))
2806 gst_object_ref (result);
2807 GST_OBJECT_UNLOCK (element);
2809 GST_DEBUG_OBJECT (element, "got bus %" GST_PTR_FORMAT, result);