2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2004 Wim Taymans <wim@fluendo.com>
5 * gstelement.c: The base element, all elements derive from this
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Abstract base class for all pipeline elements
26 * @see_also: #GstElementFactory, #GstPad
28 * GstElement is the abstract base class needed to construct an element that
29 * can be used in a GStreamer pipeline. Please refer to the plugin writers
30 * guide for more information on creating #GstElement subclasses.
32 * The name of a #GstElement can be get with gst_element_get_name() and set with
33 * gst_element_set_name(). For speed, GST_ELEMENT_NAME() can be used in the
34 * core when using the appropriate locking. Do not use this in plug-ins or
35 * applications in order to retain ABI compatibility.
37 * All elements have pads (of the type #GstPad). These pads link to pads on
38 * other elements. #GstBuffer flow between these linked pads.
39 * A #GstElement has a #GList of #GstPad structures for all their input (or sink)
40 * and output (or source) pads.
41 * Core and plug-in writers can add and remove pads with gst_element_add_pad()
42 * and gst_element_remove_pad().
44 * An existing pad of an element can be retrieved by name with
45 * gst_element_get_static_pad(). A new dynamic pad can be created using
46 * gst_element_request_pad() with a #GstPadTemplate or
47 * gst_element_get_request_pad() with the template name such as "src_\%d".
48 * An iterator of all pads can be retrieved with gst_element_iterate_pads().
50 * Elements can be linked through their pads.
51 * If the link is straightforward, use the gst_element_link()
52 * convenience function to link two elements, or gst_element_link_many()
53 * for more elements in a row.
54 * Use gst_element_link_filtered() to link two elements constrained by
55 * a specified set of #GstCaps.
56 * For finer control, use gst_element_link_pads() and
57 * gst_element_link_pads_filtered() to specify the pads to link on
58 * each element by name.
60 * Each element has a state (see #GstState). You can get and set the state
61 * of an element with gst_element_get_state() and gst_element_set_state().
62 * Setting a state triggers a #GstStateChange. To get a string representation
63 * of a #GstState, use gst_element_state_get_name().
65 * You can get and set a #GstClock on an element using gst_element_get_clock()
66 * and gst_element_set_clock().
67 * Some elements can provide a clock for the pipeline if
68 * gst_element_provides_clock() returns %TRUE. With the
69 * gst_element_provide_clock() method one can retrieve the clock provided by
71 * Not all elements require a clock to operate correctly. If
72 * gst_element_requires_clock() returns %TRUE, a clock should be set on the
73 * element with gst_element_set_clock().
75 * Note that clock slection and distribution is normally handled by the
76 * toplevel #GstPipeline so the clock functions are only to be used in very
77 * specific situations.
79 * Last reviewed on 2009-05-29 (0.10.24)
82 /* FIXME 0.11: suppress warnings for deprecated API such as GStaticRecMutex
83 * with newer GLib versions (>= 2.31.0) */
84 #define GLIB_DISABLE_DEPRECATION_WARNINGS
85 #include "gst_private.h"
88 #include <gobject/gvaluecollector.h>
90 #include "gstelement.h"
91 #include "gstelementmetadata.h"
92 #include "gstenumtypes.h"
94 #include "gstmarshal.h"
100 #include "gst-i18n-lib.h"
101 #include "glib-compat-private.h"
103 /* Element signals and args */
119 static void gst_element_class_init (GstElementClass * klass);
120 static void gst_element_init (GstElement * element);
121 static void gst_element_base_class_init (gpointer g_class);
122 static void gst_element_base_class_finalize (gpointer g_class);
124 static void gst_element_dispose (GObject * object);
125 static void gst_element_finalize (GObject * object);
127 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
128 GstStateChange transition);
129 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
130 GstState * state, GstState * pending, GstClockTime timeout);
131 static GstStateChangeReturn gst_element_set_state_func (GstElement * element,
133 static gboolean gst_element_set_clock_func (GstElement * element,
135 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
137 static gboolean gst_element_default_send_event (GstElement * element,
139 static gboolean gst_element_default_query (GstElement * element,
142 static GstPadTemplate
143 * gst_element_class_get_request_pad_template (GstElementClass *
144 element_class, const gchar * name);
146 static GstObjectClass *parent_class = NULL;
147 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
149 /* this is used in gstelementfactory.c:gst_element_register() */
150 GQuark __gst_elementclass_factory = 0;
153 gst_element_get_type (void)
155 static volatile gsize gst_element_type = 0;
157 if (g_once_init_enter (&gst_element_type)) {
159 static const GTypeInfo element_info = {
160 sizeof (GstElementClass),
161 gst_element_base_class_init,
162 gst_element_base_class_finalize,
163 (GClassInitFunc) gst_element_class_init,
168 (GInstanceInitFunc) gst_element_init,
172 _type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
173 &element_info, G_TYPE_FLAG_ABSTRACT);
175 __gst_elementclass_factory =
176 g_quark_from_static_string ("GST_ELEMENTCLASS_FACTORY");
177 g_once_init_leave (&gst_element_type, _type);
179 return gst_element_type;
183 gst_element_class_init (GstElementClass * klass)
185 GObjectClass *gobject_class;
187 gobject_class = (GObjectClass *) klass;
189 parent_class = g_type_class_peek_parent (klass);
192 * GstElement::pad-added:
193 * @gstelement: the object which received the signal
194 * @new_pad: the pad that has been added
196 * a new #GstPad has been added to the element. Note that this signal will
197 * usually be emitted from the context of the streaming thread. Also keep in
198 * mind that if you add new elements to the pipeline in the signal handler
199 * you will need to set them to the desired target state with
200 * gst_element_set_state() or gst_element_sync_state_with_parent().
202 gst_element_signals[PAD_ADDED] =
203 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
204 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
205 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
207 * GstElement::pad-removed:
208 * @gstelement: the object which received the signal
209 * @old_pad: the pad that has been removed
211 * a #GstPad has been removed from the element
213 gst_element_signals[PAD_REMOVED] =
214 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
215 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
216 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
218 * GstElement::no-more-pads:
219 * @gstelement: the object which received the signal
221 * This signals that the element will not generate more dynamic pads.
222 * Note that this signal will usually be emitted from the context of
223 * the streaming thread.
225 gst_element_signals[NO_MORE_PADS] =
226 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
227 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
228 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
230 gobject_class->dispose = gst_element_dispose;
231 gobject_class->finalize = gst_element_finalize;
233 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
234 klass->set_state = GST_DEBUG_FUNCPTR (gst_element_set_state_func);
235 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
236 klass->set_clock = GST_DEBUG_FUNCPTR (gst_element_set_clock_func);
237 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
238 klass->query = GST_DEBUG_FUNCPTR (gst_element_default_query);
239 klass->send_event = GST_DEBUG_FUNCPTR (gst_element_default_send_event);
240 klass->numpadtemplates = 0;
242 klass->elementfactory = NULL;
246 gst_element_base_class_init (gpointer g_class)
248 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
249 GList *node, *padtemplates;
251 /* Copy the element details here so elements can inherit the
252 * details from their base class and classes only need to set
253 * the details in class_init instead of base_init */
254 element_class->metadata =
255 element_class->metadata ? gst_structure_copy (element_class->metadata) :
256 gst_structure_new_empty ("metadata");
258 /* Copy the pad templates so elements inherit them
259 * from their base class but elements can add pad templates in class_init
260 * instead of base_init.
262 padtemplates = g_list_copy (element_class->padtemplates);
263 for (node = padtemplates; node != NULL; node = node->next) {
264 GstPadTemplate *tmpl = (GstPadTemplate *) node->data;
265 gst_object_ref (tmpl);
267 element_class->padtemplates = padtemplates;
269 /* set the factory, see gst_element_register() */
270 element_class->elementfactory =
271 g_type_get_qdata (G_TYPE_FROM_CLASS (element_class),
272 __gst_elementclass_factory);
273 GST_DEBUG ("type %s : factory %p", G_OBJECT_CLASS_NAME (element_class),
274 element_class->elementfactory);
278 gst_element_base_class_finalize (gpointer g_class)
280 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
282 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
283 g_list_free (klass->padtemplates);
285 gst_structure_free (klass->metadata);
289 gst_element_init (GstElement * element)
291 GST_STATE (element) = GST_STATE_NULL;
292 GST_STATE_TARGET (element) = GST_STATE_NULL;
293 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
294 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
295 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
297 g_static_rec_mutex_init (&element->state_lock);
298 element->state_cond = g_cond_new ();
302 * gst_element_release_request_pad:
303 * @element: a #GstElement to release the request pad of.
304 * @pad: the #GstPad to release.
306 * Makes the element free the previously requested pad as obtained
307 * with gst_element_get_request_pad().
309 * This does not unref the pad. If the pad was created by using
310 * gst_element_get_request_pad(), gst_element_release_request_pad() needs to be
311 * followed by gst_object_unref() to free the @pad.
316 gst_element_release_request_pad (GstElement * element, GstPad * pad)
318 GstElementClass *oclass;
320 g_return_if_fail (GST_IS_ELEMENT (element));
321 g_return_if_fail (GST_IS_PAD (pad));
323 oclass = GST_ELEMENT_GET_CLASS (element);
325 /* if the element implements a custom release function we call that, else we
326 * simply remove the pad from the element */
327 if (oclass->release_pad)
328 (oclass->release_pad) (element, pad);
330 gst_element_remove_pad (element, pad);
334 * gst_element_provide_clock:
335 * @element: a #GstElement to query
337 * Get the clock provided by the given element.
338 * <note>An element is only required to provide a clock in the PAUSED
339 * state. Some elements can provide a clock in other states.</note>
341 * Returns: (transfer full): the GstClock provided by the element or %NULL
342 * if no clock could be provided. Unref after usage.
347 gst_element_provide_clock (GstElement * element)
349 GstClock *result = NULL;
350 GstElementClass *oclass;
352 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
354 oclass = GST_ELEMENT_GET_CLASS (element);
356 if (oclass->provide_clock)
357 result = oclass->provide_clock (element);
363 gst_element_set_clock_func (GstElement * element, GstClock * clock)
367 GST_OBJECT_LOCK (element);
368 clock_p = &element->clock;
369 gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);
370 GST_OBJECT_UNLOCK (element);
376 * gst_element_set_clock:
377 * @element: a #GstElement to set the clock for.
378 * @clock: the #GstClock to set for the element.
380 * Sets the clock for the element. This function increases the
381 * refcount on the clock. Any previously set clock on the object
384 * Returns: %TRUE if the element accepted the clock. An element can refuse a
385 * clock when it, for example, is not able to slave its internal clock to the
386 * @clock or when it requires a specific clock to operate.
391 gst_element_set_clock (GstElement * element, GstClock * clock)
393 GstElementClass *oclass;
394 gboolean res = FALSE;
396 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
397 g_return_val_if_fail (clock == NULL || GST_IS_CLOCK (clock), FALSE);
399 oclass = GST_ELEMENT_GET_CLASS (element);
401 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element, "setting clock %p", clock);
403 if (oclass->set_clock)
404 res = oclass->set_clock (element, clock);
410 * gst_element_get_clock:
411 * @element: a #GstElement to get the clock of.
413 * Gets the currently configured clock of the element. This is the clock as was
414 * last set with gst_element_set_clock().
416 * Returns: (transfer full): the #GstClock of the element. unref after usage.
421 gst_element_get_clock (GstElement * element)
425 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
427 GST_OBJECT_LOCK (element);
428 if ((result = element->clock))
429 gst_object_ref (result);
430 GST_OBJECT_UNLOCK (element);
436 * gst_element_set_base_time:
437 * @element: a #GstElement.
438 * @time: the base time to set.
440 * Set the base time of an element. See gst_element_get_base_time().
445 gst_element_set_base_time (GstElement * element, GstClockTime time)
449 g_return_if_fail (GST_IS_ELEMENT (element));
451 GST_OBJECT_LOCK (element);
452 old = element->base_time;
453 element->base_time = time;
454 GST_OBJECT_UNLOCK (element);
456 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
457 "set base_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
458 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
462 * gst_element_get_base_time:
463 * @element: a #GstElement.
465 * Returns the base time of the element. The base time is the
466 * absolute time of the clock when this element was last put to
467 * PLAYING. Subtracting the base time from the clock time gives
468 * the running time of the element.
470 * Returns: the base time of the element.
475 gst_element_get_base_time (GstElement * element)
479 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
481 GST_OBJECT_LOCK (element);
482 result = element->base_time;
483 GST_OBJECT_UNLOCK (element);
489 * gst_element_set_start_time:
490 * @element: a #GstElement.
491 * @time: the base time to set.
493 * Set the start time of an element. The start time of the element is the
494 * running time of the element when it last went to the PAUSED state. In READY
495 * or after a flushing seek, it is set to 0.
497 * Toplevel elements like #GstPipeline will manage the start_time and
498 * base_time on its children. Setting the start_time to #GST_CLOCK_TIME_NONE
499 * on such a toplevel element will disable the distribution of the base_time to
500 * the children and can be useful if the application manages the base_time
501 * itself, for example if you want to synchronize capture from multiple
502 * pipelines, and you can also ensure that the pipelines have the same clock.
509 gst_element_set_start_time (GstElement * element, GstClockTime time)
513 g_return_if_fail (GST_IS_ELEMENT (element));
515 GST_OBJECT_LOCK (element);
516 old = GST_ELEMENT_START_TIME (element);
517 GST_ELEMENT_START_TIME (element) = time;
518 GST_OBJECT_UNLOCK (element);
520 GST_CAT_DEBUG_OBJECT (GST_CAT_CLOCK, element,
521 "set start_time=%" GST_TIME_FORMAT ", old %" GST_TIME_FORMAT,
522 GST_TIME_ARGS (time), GST_TIME_ARGS (old));
526 * gst_element_get_start_time:
527 * @element: a #GstElement.
529 * Returns the start time of the element. The start time is the
530 * running time of the clock when this element was last put to PAUSED.
532 * Usually the start_time is managed by a toplevel element such as
537 * Returns: the start time of the element.
542 gst_element_get_start_time (GstElement * element)
546 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
548 GST_OBJECT_LOCK (element);
549 result = GST_ELEMENT_START_TIME (element);
550 GST_OBJECT_UNLOCK (element);
557 * gst_element_set_index:
558 * @element: a #GstElement.
559 * @index: (transfer none): a #GstIndex.
561 * Set @index on the element. The refcount of the index
562 * will be increased, any previously set index is unreffed.
567 gst_element_set_index (GstElement * element, GstIndex * index)
569 GstElementClass *oclass;
571 g_return_if_fail (GST_IS_ELEMENT (element));
572 g_return_if_fail (index == NULL || GST_IS_INDEX (index));
574 oclass = GST_ELEMENT_GET_CLASS (element);
576 if (oclass->set_index)
577 oclass->set_index (element, index);
581 * gst_element_get_index:
582 * @element: a #GstElement.
584 * Gets the index from the element.
586 * Returns: (transfer full): a #GstIndex or %NULL when no index was set on the
587 * element. unref after usage.
592 gst_element_get_index (GstElement * element)
594 GstElementClass *oclass;
595 GstIndex *result = NULL;
597 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
599 oclass = GST_ELEMENT_GET_CLASS (element);
601 if (oclass->get_index)
602 result = oclass->get_index (element);
609 * gst_element_add_pad:
610 * @element: a #GstElement to add the pad to.
611 * @pad: (transfer full): the #GstPad to add to the element.
613 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
614 * see gst_object_set_parent() for refcounting information.
616 * Pads are not automatically activated so elements should perform the needed
617 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
618 * state. See gst_pad_set_active() for more information about activating pads.
620 * The pad and the element should be unlocked when calling this function.
622 * This function will emit the #GstElement::pad-added signal on the element.
624 * Returns: %TRUE if the pad could be added. This function can fail when
625 * a pad with the same name already existed or the pad already had another
631 gst_element_add_pad (GstElement * element, GstPad * pad)
636 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
637 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
639 /* locking pad to look at the name */
640 GST_OBJECT_LOCK (pad);
641 pad_name = g_strdup (GST_PAD_NAME (pad));
642 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
643 GST_STR_NULL (pad_name));
644 flushing = GST_PAD_IS_FLUSHING (pad);
645 GST_OBJECT_FLAG_SET (pad, GST_PAD_FLAG_NEED_PARENT);
646 GST_OBJECT_UNLOCK (pad);
648 /* then check to see if there's already a pad by that name here */
649 GST_OBJECT_LOCK (element);
650 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
653 /* try to set the pad's parent */
654 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
655 GST_OBJECT_CAST (element))))
658 /* check for flushing pads */
659 if (flushing && (GST_STATE (element) > GST_STATE_READY ||
660 GST_STATE_NEXT (element) == GST_STATE_PAUSED)) {
661 g_warning ("adding flushing pad '%s' to running element '%s', you need to "
662 "use gst_pad_set_active(pad,TRUE) before adding it.",
663 GST_STR_NULL (pad_name), GST_ELEMENT_NAME (element));
665 GST_OBJECT_LOCK (pad);
666 GST_PAD_UNSET_FLUSHING (pad);
667 GST_OBJECT_UNLOCK (pad);
672 /* add it to the list */
673 switch (gst_pad_get_direction (pad)) {
675 element->srcpads = g_list_prepend (element->srcpads, pad);
676 element->numsrcpads++;
679 element->sinkpads = g_list_prepend (element->sinkpads, pad);
680 element->numsinkpads++;
685 element->pads = g_list_prepend (element->pads, pad);
687 element->pads_cookie++;
688 GST_OBJECT_UNLOCK (element);
690 /* emit the PAD_ADDED signal */
691 g_signal_emit (element, gst_element_signals[PAD_ADDED], 0, pad);
698 g_critical ("Padname %s is not unique in element %s, not adding",
699 pad_name, GST_ELEMENT_NAME (element));
700 GST_OBJECT_UNLOCK (element);
707 ("Pad %s already has parent when trying to add to element %s",
708 pad_name, GST_ELEMENT_NAME (element));
709 GST_OBJECT_UNLOCK (element);
715 GST_OBJECT_LOCK (pad);
717 ("Trying to add pad %s to element %s, but it has no direction",
718 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
719 GST_OBJECT_UNLOCK (pad);
720 GST_OBJECT_UNLOCK (element);
726 * gst_element_remove_pad:
727 * @element: a #GstElement to remove pad from.
728 * @pad: (transfer none): the #GstPad to remove from the element.
730 * Removes @pad from @element. @pad will be destroyed if it has not been
731 * referenced elsewhere using gst_object_unparent().
733 * This function is used by plugin developers and should not be used
734 * by applications. Pads that were dynamically requested from elements
735 * with gst_element_get_request_pad() should be released with the
736 * gst_element_release_request_pad() function instead.
738 * Pads are not automatically deactivated so elements should perform the needed
739 * steps to deactivate the pad in case this pad is removed in the PAUSED or
740 * PLAYING state. See gst_pad_set_active() for more information about
743 * The pad and the element should be unlocked when calling this function.
745 * This function will emit the #GstElement::pad-removed signal on the element.
747 * Returns: %TRUE if the pad could be removed. Can return %FALSE if the
748 * pad does not belong to the provided element.
753 gst_element_remove_pad (GstElement * element, GstPad * pad)
757 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
758 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
760 /* locking pad to look at the name and parent */
761 GST_OBJECT_LOCK (pad);
762 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
763 GST_STR_NULL (GST_PAD_NAME (pad)));
765 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
767 GST_OBJECT_UNLOCK (pad);
770 if ((peer = gst_pad_get_peer (pad))) {
771 /* window for MT unsafeness, someone else could unlink here
772 * and then we call unlink with wrong pads. The unlink
773 * function would catch this and safely return failed. */
774 if (GST_PAD_IS_SRC (pad))
775 gst_pad_unlink (pad, peer);
777 gst_pad_unlink (peer, pad);
779 gst_object_unref (peer);
782 GST_OBJECT_LOCK (element);
783 /* remove it from the list */
784 switch (gst_pad_get_direction (pad)) {
786 element->srcpads = g_list_remove (element->srcpads, pad);
787 element->numsrcpads--;
790 element->sinkpads = g_list_remove (element->sinkpads, pad);
791 element->numsinkpads--;
794 g_critical ("Removing pad without direction???");
797 element->pads = g_list_remove (element->pads, pad);
799 element->pads_cookie++;
800 GST_OBJECT_UNLOCK (element);
802 /* emit the PAD_REMOVED signal before unparenting and losing the last ref. */
803 g_signal_emit (element, gst_element_signals[PAD_REMOVED], 0, pad);
805 gst_object_unparent (GST_OBJECT_CAST (pad));
812 /* locking order is element > pad */
813 GST_OBJECT_UNLOCK (pad);
815 GST_OBJECT_LOCK (element);
816 GST_OBJECT_LOCK (pad);
817 g_critical ("Padname %s:%s does not belong to element %s when removing",
818 GST_DEBUG_PAD_NAME (pad), GST_ELEMENT_NAME (element));
819 GST_OBJECT_UNLOCK (pad);
820 GST_OBJECT_UNLOCK (element);
826 * gst_element_no_more_pads:
827 * @element: a #GstElement
829 * Use this function to signal that the element does not expect any more pads
830 * to show up in the current pipeline. This function should be called whenever
831 * pads have been added by the element itself. Elements with #GST_PAD_SOMETIMES
832 * pad templates use this in combination with autopluggers to figure out that
833 * the element is done initializing its pads.
835 * This function emits the #GstElement::no-more-pads signal.
840 gst_element_no_more_pads (GstElement * element)
842 g_return_if_fail (GST_IS_ELEMENT (element));
844 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
848 pad_compare_name (GstPad * pad1, const gchar * name)
852 GST_OBJECT_LOCK (pad1);
853 result = strcmp (GST_PAD_NAME (pad1), name);
854 GST_OBJECT_UNLOCK (pad1);
860 * gst_element_get_static_pad:
861 * @element: a #GstElement to find a static pad of.
862 * @name: the name of the static #GstPad to retrieve.
864 * Retrieves a pad from @element by name. This version only retrieves
865 * already-existing (i.e. 'static') pads.
867 * Returns: (transfer full): the requested #GstPad if found, otherwise %NULL.
873 gst_element_get_static_pad (GstElement * element, const gchar * name)
876 GstPad *result = NULL;
878 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
879 g_return_val_if_fail (name != NULL, NULL);
881 GST_OBJECT_LOCK (element);
883 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
885 result = GST_PAD_CAST (find->data);
886 gst_object_ref (result);
889 if (result == NULL) {
890 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
891 name, GST_ELEMENT_NAME (element));
893 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
894 GST_ELEMENT_NAME (element), name);
896 GST_OBJECT_UNLOCK (element);
902 _gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
903 const gchar * name, const GstCaps * caps)
905 GstPad *newpad = NULL;
906 GstElementClass *oclass;
908 oclass = GST_ELEMENT_GET_CLASS (element);
910 #ifndef G_DISABLE_CHECKS
911 /* Some sanity checking here */
915 /* Is this the template name? */
916 if (strstr (name, "%") || !strchr (templ->name_template, '%')) {
917 g_return_val_if_fail (strcmp (name, templ->name_template) == 0, NULL);
919 const gchar *str, *data;
922 /* Otherwise check if it's a valid name for the name template */
923 str = strchr (templ->name_template, '%');
924 g_return_val_if_fail (str != NULL, NULL);
925 g_return_val_if_fail (strncmp (templ->name_template, name,
926 str - templ->name_template) == 0, NULL);
927 g_return_val_if_fail (strlen (name) > str - templ->name_template, NULL);
929 data = name + (str - templ->name_template);
931 /* Can either be %s or %d or %u, do sanity checking for %d */
932 if (*(str + 1) == 'd') {
936 tmp = g_ascii_strtoll (data, &endptr, 10);
937 g_return_val_if_fail (tmp >= G_MININT && tmp <= G_MAXINT
938 && *endptr == '\0', NULL);
939 } else if (*(str + 1) == 'u') {
943 tmp = g_ascii_strtoull (data, &endptr, 10);
944 g_return_val_if_fail (tmp <= G_MAXUINT && *endptr == '\0', NULL);
948 pad = gst_element_get_static_pad (element, name);
950 gst_object_unref (pad);
951 /* FIXME 0.11: Change this to g_return_val_if_fail() */
952 g_critical ("Element %s already has a pad named %s, the behaviour of "
953 " gst_element_get_request_pad() for existing pads is undefined!",
954 GST_ELEMENT_NAME (element), name);
959 if (oclass->request_new_pad)
960 newpad = (oclass->request_new_pad) (element, templ, name, caps);
963 gst_object_ref (newpad);
969 * gst_element_get_request_pad:
970 * @element: a #GstElement to find a request pad of.
971 * @name: the name of the request #GstPad to retrieve.
973 * Retrieves a pad from the element by name (e.g. "src_\%d"). This version only
974 * retrieves request pads. The pad should be released with
975 * gst_element_release_request_pad().
977 * This method is slow and will be deprecated in the future. New code should
978 * use gst_element_request_pad() with the requested template.
980 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
981 * Release after usage.
984 gst_element_get_request_pad (GstElement * element, const gchar * name)
986 GstPadTemplate *templ = NULL;
988 const gchar *req_name = NULL;
989 gboolean templ_found = FALSE;
992 gchar *str, *endptr = NULL;
993 GstElementClass *class;
995 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
996 g_return_val_if_fail (name != NULL, NULL);
998 class = GST_ELEMENT_GET_CLASS (element);
1000 /* if the name contains a %, we assume it's the complete template name. Get
1001 * the template and try to get a pad */
1002 if (strstr (name, "%")) {
1003 templ = gst_element_class_get_request_pad_template (class, name);
1008 /* there is no % in the name, try to find a matching template */
1009 list = class->padtemplates;
1010 while (!templ_found && list) {
1011 templ = (GstPadTemplate *) list->data;
1012 if (templ->presence == GST_PAD_REQUEST) {
1013 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
1014 templ->name_template);
1015 /* see if we find an exact match */
1016 if (strcmp (name, templ->name_template) == 0) {
1021 /* Because of sanity checks in gst_pad_template_new(), we know that %s
1022 and %d and %u, occurring at the end of the name_template, are the only
1024 else if ((str = strchr (templ->name_template, '%'))
1025 && strncmp (templ->name_template, name,
1026 str - templ->name_template) == 0
1027 && strlen (name) > str - templ->name_template) {
1028 data = name + (str - templ->name_template);
1029 if (*(str + 1) == 'd') {
1033 tmp = strtol (data, &endptr, 10);
1034 if (tmp != G_MINLONG && tmp != G_MAXLONG && endptr &&
1040 } else if (*(str + 1) == 'u') {
1044 tmp = strtoul (data, &endptr, 10);
1045 if (tmp != G_MAXULONG && endptr && *endptr == '\0') {
1065 pad = _gst_element_request_pad (element, templ, req_name, NULL);
1071 * gst_element_request_pad:
1072 * @element: a #GstElement to find a request pad of.
1073 * @templ: a #GstPadTemplate of which we want a pad of.
1074 * @name: (transfer none) (allow-none): the name of the request #GstPad
1075 * to retrieve. Can be %NULL.
1076 * @caps: (transfer none) (allow-none): the caps of the pad we want to
1077 * request. Can be %NULL.
1079 * Retrieves a request pad from the element according to the provided template.
1080 * Pad templates can be looked up using
1081 * gst_element_factory_get_static_pad_templates().
1083 * The pad should be released with gst_element_release_request_pad().
1085 * Returns: (transfer full): requested #GstPad if found, otherwise %NULL.
1086 * Release after usage.
1091 gst_element_request_pad (GstElement * element,
1092 GstPadTemplate * templ, const gchar * name, const GstCaps * caps)
1094 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1095 g_return_val_if_fail (templ != NULL, NULL);
1097 return _gst_element_request_pad (element, templ, name, caps);
1100 static GstIterator *
1101 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
1103 GstIterator *result;
1105 GST_OBJECT_LOCK (element);
1106 result = gst_iterator_new_list (GST_TYPE_PAD,
1107 GST_OBJECT_GET_LOCK (element),
1108 &element->pads_cookie, padlist, (GObject *) element, NULL);
1109 GST_OBJECT_UNLOCK (element);
1115 * gst_element_iterate_pads:
1116 * @element: a #GstElement to iterate pads of.
1118 * Retrieves an iterator of @element's pads. The iterator should
1119 * be freed after usage. Also more specialized iterators exists such as
1120 * gst_element_iterate_src_pads() or gst_element_iterate_sink_pads().
1122 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1128 gst_element_iterate_pads (GstElement * element)
1130 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1132 return gst_element_iterate_pad_list (element, &element->pads);
1136 * gst_element_iterate_src_pads:
1137 * @element: a #GstElement.
1139 * Retrieves an iterator of @element's source pads.
1141 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1147 gst_element_iterate_src_pads (GstElement * element)
1149 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1151 return gst_element_iterate_pad_list (element, &element->srcpads);
1155 * gst_element_iterate_sink_pads:
1156 * @element: a #GstElement.
1158 * Retrieves an iterator of @element's sink pads.
1160 * Returns: (transfer full): the #GstIterator of #GstPad. Unref each pad
1166 gst_element_iterate_sink_pads (GstElement * element)
1168 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1170 return gst_element_iterate_pad_list (element, &element->sinkpads);
1174 * gst_element_class_add_pad_template:
1175 * @klass: the #GstElementClass to add the pad template to.
1176 * @templ: (transfer full): a #GstPadTemplate to add to the element class.
1178 * Adds a padtemplate to an element class. This is mainly used in the _class_init
1179 * functions of classes. If a pad template with the same name as an already
1180 * existing one is added the old one is replaced by the new one.
1184 gst_element_class_add_pad_template (GstElementClass * klass,
1185 GstPadTemplate * templ)
1187 GList *template_list = klass->padtemplates;
1189 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1190 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1192 /* If we already have a pad template with the same name replace the
1194 while (template_list) {
1195 GstPadTemplate *padtempl = (GstPadTemplate *) template_list->data;
1197 /* Found pad with the same name, replace and return */
1198 if (strcmp (templ->name_template, padtempl->name_template) == 0) {
1199 gst_object_unref (padtempl);
1200 template_list->data = templ;
1203 template_list = g_list_next (template_list);
1206 /* Take ownership of the floating ref */
1207 gst_object_ref_sink (templ);
1209 klass->padtemplates = g_list_append (klass->padtemplates, templ);
1210 klass->numpadtemplates++;
1214 * gst_element_class_add_metadata:
1215 * @klass: class to set metadata for
1216 * @key: the key to set
1217 * @value: the value to set
1219 * Set @key with @value as metadata in @klass.
1222 gst_element_class_add_metadata (GstElementClass * klass,
1223 const gchar * key, const gchar * value)
1225 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1226 g_return_if_fail (key != NULL);
1227 g_return_if_fail (value != NULL);
1229 gst_structure_set ((GstStructure *) klass->metadata,
1230 key, G_TYPE_STRING, value, NULL);
1234 * gst_element_class_set_metadata:
1235 * @klass: class to set metadata for
1236 * @longname: The long English name of the element. E.g. "File Sink"
1237 * @classification: String describing the type of element, as an unordered list
1238 * separated with slashes ('/'). See draft-klass.txt of the design docs
1239 * for more details and common types. E.g: "Sink/File"
1240 * @description: Sentence describing the purpose of the element.
1241 * E.g: "Write stream to a file"
1242 * @author: Name and contact details of the author(s). Use \n to separate
1243 * multiple author metadata. E.g: "Joe Bloggs <joe.blogs at foo.com>"
1245 * Sets the detailed information for a #GstElementClass.
1246 * <note>This function is for use in _class_init functions only.</note>
1249 gst_element_class_set_metadata (GstElementClass * klass,
1250 const gchar * longname, const gchar * classification,
1251 const gchar * description, const gchar * author)
1253 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1255 gst_structure_set ((GstStructure *) klass->metadata,
1256 GST_ELEMENT_METADATA_LONGNAME, G_TYPE_STRING, longname,
1257 GST_ELEMENT_METADATA_KLASS, G_TYPE_STRING, classification,
1258 GST_ELEMENT_METADATA_DESCRIPTION, G_TYPE_STRING, description,
1259 GST_ELEMENT_METADATA_AUTHOR, G_TYPE_STRING, author, NULL);
1263 * gst_element_class_get_metadata:
1264 * @klass: class to get metadata for
1265 * @key: the key to get
1267 * Get metadata with @key in @klass.
1269 * Returns: the metadata for @key.
1272 gst_element_class_get_metadata (GstElementClass * klass, const gchar * key)
1274 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (klass), NULL);
1275 g_return_val_if_fail (key != NULL, NULL);
1277 return gst_structure_get_string ((GstStructure *) klass->metadata, key);
1281 * gst_element_class_get_pad_template_list:
1282 * @element_class: a #GstElementClass to get pad templates of.
1284 * Retrieves a list of the pad templates associated with @element_class. The
1285 * list must not be modified by the calling code.
1286 * <note>If you use this function in the #GInstanceInitFunc of an object class
1287 * that has subclasses, make sure to pass the g_class parameter of the
1288 * #GInstanceInitFunc here.</note>
1290 * Returns: (transfer none) (element-type Gst.PadTemplate): the #GList of
1294 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1296 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1298 return element_class->padtemplates;
1302 * gst_element_class_get_pad_template:
1303 * @element_class: a #GstElementClass to get the pad template of.
1304 * @name: the name of the #GstPadTemplate to get.
1306 * Retrieves a padtemplate from @element_class with the given name.
1307 * <note>If you use this function in the #GInstanceInitFunc of an object class
1308 * that has subclasses, make sure to pass the g_class parameter of the
1309 * #GInstanceInitFunc here.</note>
1311 * Returns: (transfer none): the #GstPadTemplate with the given name, or %NULL
1312 * if none was found. No unreferencing is necessary.
1315 gst_element_class_get_pad_template (GstElementClass *
1316 element_class, const gchar * name)
1320 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1321 g_return_val_if_fail (name != NULL, NULL);
1323 padlist = element_class->padtemplates;
1326 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1328 if (strcmp (padtempl->name_template, name) == 0)
1331 padlist = g_list_next (padlist);
1337 static GstPadTemplate *
1338 gst_element_class_get_request_pad_template (GstElementClass *
1339 element_class, const gchar * name)
1341 GstPadTemplate *tmpl;
1343 tmpl = gst_element_class_get_pad_template (element_class, name);
1344 if (tmpl != NULL && tmpl->presence == GST_PAD_REQUEST)
1350 /* get a random pad on element of the given direction.
1351 * The pad is random in a sense that it is the first pad that is (optionaly) linked.
1354 gst_element_get_random_pad (GstElement * element,
1355 gboolean need_linked, GstPadDirection dir)
1357 GstPad *result = NULL;
1360 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1364 GST_OBJECT_LOCK (element);
1365 pads = element->srcpads;
1368 GST_OBJECT_LOCK (element);
1369 pads = element->sinkpads;
1372 goto wrong_direction;
1374 for (; pads; pads = g_list_next (pads)) {
1375 GstPad *pad = GST_PAD_CAST (pads->data);
1377 GST_OBJECT_LOCK (pad);
1378 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1379 GST_DEBUG_PAD_NAME (pad));
1381 if (need_linked && !GST_PAD_IS_LINKED (pad)) {
1382 /* if we require a linked pad, and it is not linked, continue the
1384 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1385 GST_DEBUG_PAD_NAME (pad));
1386 GST_OBJECT_UNLOCK (pad);
1389 /* found a pad, stop search */
1390 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
1391 GST_DEBUG_PAD_NAME (pad));
1392 GST_OBJECT_UNLOCK (pad);
1398 gst_object_ref (result);
1400 GST_OBJECT_UNLOCK (element);
1404 /* ERROR handling */
1407 g_warning ("unknown pad direction %d", dir);
1413 gst_element_default_send_event (GstElement * element, GstEvent * event)
1415 gboolean result = FALSE;
1418 pad = GST_EVENT_IS_DOWNSTREAM (event) ?
1419 gst_element_get_random_pad (element, TRUE, GST_PAD_SRC) :
1420 gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1423 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1424 "pushing %s event to random %s pad %s:%s",
1425 GST_EVENT_TYPE_NAME (event),
1426 (GST_PAD_DIRECTION (pad) == GST_PAD_SRC ? "src" : "sink"),
1427 GST_DEBUG_PAD_NAME (pad));
1429 result = gst_pad_push_event (pad, event);
1430 gst_object_unref (pad);
1432 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "can't send %s event on element %s",
1433 GST_EVENT_TYPE_NAME (event), GST_ELEMENT_NAME (element));
1434 gst_event_unref (event);
1440 * gst_element_send_event:
1441 * @element: a #GstElement to send the event to.
1442 * @event: (transfer full): 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 GST_STATE_UNLOCK (element);
1479 * @element: a #GstElement to send the event to.
1480 * @rate: The new playback rate
1481 * @format: The format of the seek values
1482 * @flags: The optional seek flags.
1483 * @cur_type: The type and flags for the new current position
1484 * @cur: The value of the new current position
1485 * @stop_type: The type and flags for the new stop position
1486 * @stop: The value of the new stop position
1488 * Sends a seek event to an element. See gst_event_new_seek() for the details of
1489 * the parameters. The seek event is sent to the element using
1490 * gst_element_send_event().
1492 * Returns: %TRUE if the event was handled.
1497 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1498 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1499 GstSeekType stop_type, gint64 stop)
1504 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1507 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1508 result = gst_element_send_event (element, event);
1514 gst_element_default_query (GstElement * element, GstQuery * query)
1516 gboolean result = FALSE;
1519 pad = gst_element_get_random_pad (element, FALSE, GST_PAD_SRC);
1521 result = gst_pad_query (pad, query);
1523 gst_object_unref (pad);
1525 pad = gst_element_get_random_pad (element, TRUE, GST_PAD_SINK);
1527 GstPad *peer = gst_pad_get_peer (pad);
1530 result = gst_pad_query (peer, query);
1532 gst_object_unref (peer);
1534 gst_object_unref (pad);
1541 * gst_element_query:
1542 * @element: a #GstElement to perform the query on.
1543 * @query: (transfer none): the #GstQuery.
1545 * Performs a query on the given element.
1547 * For elements that don't implement a query handler, this function
1548 * forwards the query to a random srcpad or to the peer of a
1549 * random linked sinkpad of this element.
1551 * Please note that some queries might need a running pipeline to work.
1553 * Returns: TRUE if the query could be performed.
1558 gst_element_query (GstElement * element, GstQuery * query)
1560 GstElementClass *oclass;
1561 gboolean result = FALSE;
1563 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1564 g_return_val_if_fail (query != NULL, FALSE);
1566 oclass = GST_ELEMENT_GET_CLASS (element);
1568 if (oclass->query) {
1569 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "send query on element %s",
1570 GST_ELEMENT_NAME (element));
1571 result = oclass->query (element, query);
1577 * gst_element_post_message:
1578 * @element: a #GstElement posting the message
1579 * @message: (transfer full): a #GstMessage to post
1581 * Post a message on the element's #GstBus. This function takes ownership of the
1582 * message; if you want to access the message after this call, you should add an
1583 * additional reference before calling.
1585 * Returns: %TRUE if the message was successfully posted. The function returns
1586 * %FALSE if the element did not have a bus.
1591 gst_element_post_message (GstElement * element, GstMessage * message)
1594 gboolean result = FALSE;
1596 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1597 g_return_val_if_fail (message != NULL, FALSE);
1599 GST_OBJECT_LOCK (element);
1602 if (G_UNLIKELY (bus == NULL))
1605 gst_object_ref (bus);
1606 GST_OBJECT_UNLOCK (element);
1608 /* we release the element lock when posting the message so that any
1609 * (synchronous) message handlers can operate on the element */
1610 result = gst_bus_post (bus, message);
1611 gst_object_unref (bus);
1618 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element,
1619 "not posting message %p: no bus", message);
1620 GST_OBJECT_UNLOCK (element);
1621 gst_message_unref (message);
1627 * _gst_element_error_printf:
1628 * @format: the printf-like format to use, or %NULL
1630 * This function is only used internally by the gst_element_error() macro.
1632 * Returns: (transfer full): a newly allocated string, or %NULL if the format
1638 _gst_element_error_printf (const gchar * format, ...)
1648 va_start (args, format);
1649 buffer = g_strdup_vprintf (format, args);
1655 * gst_element_message_full:
1656 * @element: a #GstElement to send message from
1657 * @type: the #GstMessageType
1658 * @domain: the GStreamer GError domain this message belongs to
1659 * @code: the GError code belonging to the domain
1660 * @text: (allow-none) (transfer full): an allocated text string to be used
1661 * as a replacement for the default message connected to code,
1663 * @debug: (allow-none) (transfer full): an allocated debug message to be
1664 * used as a replacement for the default debugging information,
1666 * @file: the source code file where the error was generated
1667 * @function: the source code function where the error was generated
1668 * @line: the source code line where the error was generated
1670 * Post an error, warning or info message on the bus from inside an element.
1672 * @type must be of #GST_MESSAGE_ERROR, #GST_MESSAGE_WARNING or
1673 * #GST_MESSAGE_INFO.
1677 void gst_element_message_full
1678 (GstElement * element, GstMessageType type,
1679 GQuark domain, gint code, gchar * text,
1680 gchar * debug, const gchar * file, const gchar * function, gint line)
1682 GError *gerror = NULL;
1686 gboolean has_debug = TRUE;
1687 GstMessage *message = NULL;
1690 GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, element, "start");
1691 g_return_if_fail (GST_IS_ELEMENT (element));
1692 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1693 (type == GST_MESSAGE_WARNING) || (type == GST_MESSAGE_INFO));
1695 /* check if we send the given text or the default error text */
1696 if ((text == NULL) || (text[0] == 0)) {
1697 /* text could have come from g_strdup_printf (""); */
1699 sent_text = gst_error_get_message (domain, code);
1703 /* construct a sent_debug with extra information from source */
1704 if ((debug == NULL) || (debug[0] == 0)) {
1705 /* debug could have come from g_strdup_printf (""); */
1709 name = gst_object_get_path_string (GST_OBJECT_CAST (element));
1711 sent_debug = g_strdup_printf ("%s(%d): %s (): %s:\n%s",
1712 file, line, function, name, debug);
1714 sent_debug = g_strdup_printf ("%s(%d): %s (): %s",
1715 file, line, function, name);
1719 /* create gerror and post message */
1720 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1722 gerror = g_error_new_literal (domain, code, sent_text);
1725 case GST_MESSAGE_ERROR:
1727 gst_message_new_error (GST_OBJECT_CAST (element), gerror, sent_debug);
1729 case GST_MESSAGE_WARNING:
1730 message = gst_message_new_warning (GST_OBJECT_CAST (element), gerror,
1733 case GST_MESSAGE_INFO:
1734 message = gst_message_new_info (GST_OBJECT_CAST (element), gerror,
1738 g_assert_not_reached ();
1741 gst_element_post_message (element, message);
1743 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted %s message: %s",
1744 (type == GST_MESSAGE_ERROR ? "error" : "warning"), sent_text);
1747 g_error_free (gerror);
1748 g_free (sent_debug);
1753 * gst_element_is_locked_state:
1754 * @element: a #GstElement.
1756 * Checks if the state of an element is locked.
1757 * If the state of an element is locked, state changes of the parent don't
1758 * affect the element.
1759 * This way you can leave currently unused elements inside bins. Just lock their
1760 * state before changing the state from #GST_STATE_NULL.
1764 * Returns: TRUE, if the element's state is locked.
1767 gst_element_is_locked_state (GstElement * element)
1771 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1773 GST_OBJECT_LOCK (element);
1774 result = GST_ELEMENT_IS_LOCKED_STATE (element);
1775 GST_OBJECT_UNLOCK (element);
1781 * gst_element_set_locked_state:
1782 * @element: a #GstElement
1783 * @locked_state: TRUE to lock the element's state
1785 * Locks the state of an element, so state changes of the parent don't affect
1786 * this element anymore.
1790 * Returns: TRUE if the state was changed, FALSE if bad parameters were given
1791 * or the elements state-locking needed no change.
1794 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1798 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1800 GST_OBJECT_LOCK (element);
1801 old = GST_ELEMENT_IS_LOCKED_STATE (element);
1803 if (G_UNLIKELY (old == locked_state))
1807 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1808 GST_ELEMENT_NAME (element));
1809 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1811 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1812 GST_ELEMENT_NAME (element));
1813 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_FLAG_LOCKED_STATE);
1815 GST_OBJECT_UNLOCK (element);
1821 GST_CAT_DEBUG (GST_CAT_STATES,
1822 "elements %s was already in locked state %d",
1823 GST_ELEMENT_NAME (element), old);
1824 GST_OBJECT_UNLOCK (element);
1831 * gst_element_sync_state_with_parent:
1832 * @element: a #GstElement.
1834 * Tries to change the state of the element to the same as its parent.
1835 * If this function returns FALSE, the state of element is undefined.
1837 * Returns: TRUE, if the element's state could be synced to the parent's state.
1842 gst_element_sync_state_with_parent (GstElement * element)
1846 GstStateChangeReturn ret;
1848 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1850 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1851 GstState parent_current, parent_pending;
1853 GST_OBJECT_LOCK (parent);
1854 parent_current = GST_STATE (parent);
1855 parent_pending = GST_STATE_PENDING (parent);
1856 GST_OBJECT_UNLOCK (parent);
1858 /* set to pending if there is one, else we set it to the current state of
1860 if (parent_pending != GST_STATE_VOID_PENDING)
1861 target = parent_pending;
1863 target = parent_current;
1865 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1866 "syncing state (%s) to parent %s %s (%s, %s)",
1867 gst_element_state_get_name (GST_STATE (element)),
1868 GST_ELEMENT_NAME (parent), gst_element_state_get_name (target),
1869 gst_element_state_get_name (parent_current),
1870 gst_element_state_get_name (parent_pending));
1872 ret = gst_element_set_state (element, target);
1873 if (ret == GST_STATE_CHANGE_FAILURE)
1876 gst_object_unref (parent);
1880 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "element has no parent");
1887 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1888 "syncing state failed (%s)",
1889 gst_element_state_change_return_get_name (ret));
1890 gst_object_unref (parent);
1896 static GstStateChangeReturn
1897 gst_element_get_state_func (GstElement * element,
1898 GstState * state, GstState * pending, GstClockTime timeout)
1900 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1901 GstState old_pending;
1903 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state, timeout %"
1904 GST_TIME_FORMAT, GST_TIME_ARGS (timeout));
1906 GST_OBJECT_LOCK (element);
1907 ret = GST_STATE_RETURN (element);
1908 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "RETURN is %s",
1909 gst_element_state_change_return_get_name (ret));
1911 /* we got an error, report immediately */
1912 if (ret == GST_STATE_CHANGE_FAILURE)
1915 /* we got no_preroll, report immediately */
1916 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1919 /* no need to wait async if we are not async */
1920 if (ret != GST_STATE_CHANGE_ASYNC)
1923 old_pending = GST_STATE_PENDING (element);
1924 if (old_pending != GST_STATE_VOID_PENDING) {
1925 GTimeVal *timeval, abstimeout;
1928 if (timeout != GST_CLOCK_TIME_NONE) {
1929 glong add = timeout / 1000;
1934 /* make timeout absolute */
1935 g_get_current_time (&abstimeout);
1936 g_time_val_add (&abstimeout, add);
1937 timeval = &abstimeout;
1941 /* get cookie to detect state changes during waiting */
1942 cookie = element->state_cookie;
1944 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1945 "waiting for element to commit state");
1947 /* we have a pending state change, wait for it to complete */
1948 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1949 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1950 /* timeout triggered */
1951 ret = GST_STATE_CHANGE_ASYNC;
1953 if (cookie != element->state_cookie)
1956 /* could be success or failure */
1957 if (old_pending == GST_STATE (element)) {
1958 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1959 ret = GST_STATE_CHANGE_SUCCESS;
1961 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1962 ret = GST_STATE_CHANGE_FAILURE;
1965 /* if nothing is pending anymore we can return SUCCESS */
1966 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1967 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1968 ret = GST_STATE_CHANGE_SUCCESS;
1974 *state = GST_STATE (element);
1976 *pending = GST_STATE_PENDING (element);
1978 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1979 "state current: %s, pending: %s, result: %s",
1980 gst_element_state_get_name (GST_STATE (element)),
1981 gst_element_state_get_name (GST_STATE_PENDING (element)),
1982 gst_element_state_change_return_get_name (ret));
1983 GST_OBJECT_UNLOCK (element);
1990 *state = GST_STATE_VOID_PENDING;
1992 *pending = GST_STATE_VOID_PENDING;
1994 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "interruped");
1996 GST_OBJECT_UNLOCK (element);
1998 return GST_STATE_CHANGE_FAILURE;
2003 * gst_element_get_state:
2004 * @element: a #GstElement to get the state of.
2005 * @state: (out) (allow-none): a pointer to #GstState to hold the state.
2007 * @pending: (out) (allow-none): a pointer to #GstState to hold the pending
2008 * state. Can be %NULL.
2009 * @timeout: a #GstClockTime to specify the timeout for an async
2010 * state change or %GST_CLOCK_TIME_NONE for infinite timeout.
2012 * Gets the state of the element.
2014 * For elements that performed an ASYNC state change, as reported by
2015 * gst_element_set_state(), this function will block up to the
2016 * specified timeout value for the state change to complete.
2017 * If the element completes the state change or goes into
2018 * an error, this function returns immediately with a return value of
2019 * %GST_STATE_CHANGE_SUCCESS or %GST_STATE_CHANGE_FAILURE respectively.
2021 * For elements that did not return %GST_STATE_CHANGE_ASYNC, this function
2022 * returns the current and pending state immediately.
2024 * This function returns %GST_STATE_CHANGE_NO_PREROLL if the element
2025 * successfully changed its state but is not able to provide data yet.
2026 * This mostly happens for live sources that only produce data in
2027 * %GST_STATE_PLAYING. While the state change return is equivalent to
2028 * %GST_STATE_CHANGE_SUCCESS, it is returned to the application to signal that
2029 * some sink elements might not be able to complete their state change because
2030 * an element is not producing data to complete the preroll. When setting the
2031 * element to playing, the preroll will complete and playback will start.
2033 * Returns: %GST_STATE_CHANGE_SUCCESS if the element has no more pending state
2034 * and the last state change succeeded, %GST_STATE_CHANGE_ASYNC if the
2035 * element is still performing a state change or
2036 * %GST_STATE_CHANGE_FAILURE if the last state change failed.
2040 GstStateChangeReturn
2041 gst_element_get_state (GstElement * element,
2042 GstState * state, GstState * pending, GstClockTime timeout)
2044 GstElementClass *oclass;
2045 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2047 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2049 oclass = GST_ELEMENT_GET_CLASS (element);
2051 if (oclass->get_state)
2052 result = (oclass->get_state) (element, state, pending, timeout);
2058 * gst_element_abort_state:
2059 * @element: a #GstElement to abort the state of.
2061 * Abort the state change of the element. This function is used
2062 * by elements that do asynchronous state changes and find out
2063 * something is wrong.
2065 * This function should be called with the STATE_LOCK held.
2070 gst_element_abort_state (GstElement * element)
2074 #ifndef GST_DISABLE_GST_DEBUG
2078 g_return_if_fail (GST_IS_ELEMENT (element));
2080 GST_OBJECT_LOCK (element);
2081 pending = GST_STATE_PENDING (element);
2083 if (pending == GST_STATE_VOID_PENDING ||
2084 GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2085 goto nothing_aborted;
2087 #ifndef GST_DISABLE_GST_DEBUG
2088 old_state = GST_STATE (element);
2090 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2091 "aborting state from %s to %s", gst_element_state_get_name (old_state),
2092 gst_element_state_get_name (pending));
2096 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
2098 GST_STATE_BROADCAST (element);
2099 GST_OBJECT_UNLOCK (element);
2105 GST_OBJECT_UNLOCK (element);
2110 /* Not static because GstBin has manual state handling too */
2112 _priv_gst_element_state_changed (GstElement * element, GstState oldstate,
2113 GstState newstate, GstState pending)
2115 GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);
2116 GstMessage *message;
2118 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2119 "notifying about state-changed %s to %s (%s pending)",
2120 gst_element_state_get_name (oldstate),
2121 gst_element_state_get_name (newstate),
2122 gst_element_state_get_name (pending));
2124 if (klass->state_changed)
2125 klass->state_changed (element, oldstate, newstate, pending);
2127 message = gst_message_new_state_changed (GST_OBJECT_CAST (element),
2128 oldstate, newstate, pending);
2129 gst_element_post_message (element, message);
2133 * gst_element_continue_state:
2134 * @element: a #GstElement to continue the state change of.
2135 * @ret: The previous state return value
2137 * Commit the state change of the element and proceed to the next
2138 * pending state if any. This function is used
2139 * by elements that do asynchronous state changes.
2140 * The core will normally call this method automatically when an
2141 * element returned %GST_STATE_CHANGE_SUCCESS from the state change function.
2143 * If after calling this method the element still has not reached
2144 * the pending state, the next state change is performed.
2146 * This method is used internally and should normally not be called by plugins
2149 * Returns: The result of the commit state change.
2153 GstStateChangeReturn
2154 gst_element_continue_state (GstElement * element, GstStateChangeReturn ret)
2156 GstStateChangeReturn old_ret;
2157 GstState old_state, old_next;
2158 GstState current, next, pending;
2159 GstStateChange transition;
2161 GST_OBJECT_LOCK (element);
2162 old_ret = GST_STATE_RETURN (element);
2163 GST_STATE_RETURN (element) = ret;
2164 pending = GST_STATE_PENDING (element);
2166 /* check if there is something to commit */
2167 if (pending == GST_STATE_VOID_PENDING)
2168 goto nothing_pending;
2170 old_state = GST_STATE (element);
2171 /* this is the state we should go to next */
2172 old_next = GST_STATE_NEXT (element);
2173 /* update current state */
2174 current = GST_STATE (element) = old_next;
2176 /* see if we reached the final state */
2177 if (pending == current)
2180 next = GST_STATE_GET_NEXT (current, pending);
2181 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2183 GST_STATE_NEXT (element) = next;
2185 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2186 GST_OBJECT_UNLOCK (element);
2188 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2189 "committing state from %s to %s, pending %s, next %s",
2190 gst_element_state_get_name (old_state),
2191 gst_element_state_get_name (old_next),
2192 gst_element_state_get_name (pending), gst_element_state_get_name (next));
2194 _priv_gst_element_state_changed (element, old_state, old_next, pending);
2196 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2197 "continue state change %s to %s, final %s",
2198 gst_element_state_get_name (current),
2199 gst_element_state_get_name (next), gst_element_state_get_name (pending));
2201 ret = gst_element_change_state (element, transition);
2207 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "nothing pending");
2208 GST_OBJECT_UNLOCK (element);
2213 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2214 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2216 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2217 "completed state change to %s", gst_element_state_get_name (pending));
2218 GST_OBJECT_UNLOCK (element);
2220 /* don't post silly messages with the same state. This can happen
2221 * when an element state is changed to what it already was. For bins
2222 * this can be the result of a lost state, which we check with the
2223 * previous return value.
2224 * We do signal the cond though as a _get_state() might be blocking
2226 if (old_state != old_next || old_ret == GST_STATE_CHANGE_ASYNC)
2227 _priv_gst_element_state_changed (element, old_state, old_next,
2228 GST_STATE_VOID_PENDING);
2230 GST_STATE_BROADCAST (element);
2237 * gst_element_lost_state:
2238 * @element: a #GstElement the state is lost of
2240 * Brings the element to the lost state. The current state of the
2241 * element is copied to the pending state so that any call to
2242 * gst_element_get_state() will return %GST_STATE_CHANGE_ASYNC.
2244 * An ASYNC_START message is posted. If the element was PLAYING, it will
2245 * go to PAUSED. The element will be restored to its PLAYING state by
2246 * the parent pipeline when it prerolls again.
2248 * This is mostly used for elements that lost their preroll buffer
2249 * in the %GST_STATE_PAUSED or %GST_STATE_PLAYING state after a flush,
2250 * they will go to their pending state again when a new preroll buffer is
2251 * queued. This function can only be called when the element is currently
2252 * not in error or an async state change.
2254 * This function is used internally and should normally not be called from
2255 * plugins or applications.
2258 gst_element_lost_state (GstElement * element)
2260 GstState old_state, new_state;
2261 GstMessage *message;
2263 g_return_if_fail (GST_IS_ELEMENT (element));
2265 GST_OBJECT_LOCK (element);
2266 if (GST_STATE_RETURN (element) == GST_STATE_CHANGE_FAILURE)
2269 if (GST_STATE_PENDING (element) != GST_STATE_VOID_PENDING)
2270 goto only_async_start;
2272 old_state = GST_STATE (element);
2274 /* when we were PLAYING, the new state is PAUSED. We will also not
2275 * automatically go to PLAYING but let the parent bin(s) set us to PLAYING
2276 * when we preroll. */
2277 if (old_state > GST_STATE_PAUSED)
2278 new_state = GST_STATE_PAUSED;
2280 new_state = old_state;
2282 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2283 "lost state of %s to %s", gst_element_state_get_name (old_state),
2284 gst_element_state_get_name (new_state));
2286 GST_STATE (element) = new_state;
2287 GST_STATE_NEXT (element) = new_state;
2288 GST_STATE_PENDING (element) = new_state;
2289 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2290 GST_OBJECT_UNLOCK (element);
2292 _priv_gst_element_state_changed (element, new_state, new_state, new_state);
2294 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2295 gst_element_post_message (element, message);
2301 GST_OBJECT_UNLOCK (element);
2306 GST_OBJECT_UNLOCK (element);
2308 message = gst_message_new_async_start (GST_OBJECT_CAST (element));
2309 gst_element_post_message (element, message);
2315 * gst_element_set_state:
2316 * @element: a #GstElement to change state of.
2317 * @state: the element's new #GstState.
2319 * Sets the state of the element. This function will try to set the
2320 * requested state by going through all the intermediary states and calling
2321 * the class's state change function for each.
2323 * This function can return #GST_STATE_CHANGE_ASYNC, in which case the
2324 * element will perform the remainder of the state change asynchronously in
2326 * An application can use gst_element_get_state() to wait for the completion
2327 * of the state change or it can wait for a state change message on the bus.
2329 * State changes to %GST_STATE_READY or %GST_STATE_NULL never return
2330 * #GST_STATE_CHANGE_ASYNC.
2332 * Returns: Result of the state change using #GstStateChangeReturn.
2336 GstStateChangeReturn
2337 gst_element_set_state (GstElement * element, GstState state)
2339 GstElementClass *oclass;
2340 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
2342 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2344 oclass = GST_ELEMENT_GET_CLASS (element);
2346 if (oclass->set_state)
2347 result = (oclass->set_state) (element, state);
2353 * default set state function, calculates the next state based
2354 * on current state and calls the change_state function
2356 static GstStateChangeReturn
2357 gst_element_set_state_func (GstElement * element, GstState state)
2359 GstState current, next, old_pending;
2360 GstStateChangeReturn ret;
2361 GstStateChange transition;
2362 GstStateChangeReturn old_ret;
2364 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2366 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
2367 gst_element_state_get_name (state));
2369 /* state lock is taken to protect the set_state() and get_state()
2370 * procedures, it does not lock any variables. */
2371 GST_STATE_LOCK (element);
2373 /* now calculate how to get to the new state */
2374 GST_OBJECT_LOCK (element);
2375 old_ret = GST_STATE_RETURN (element);
2376 /* previous state change returned an error, remove all pending
2377 * and next states */
2378 if (old_ret == GST_STATE_CHANGE_FAILURE) {
2379 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
2380 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
2381 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2384 current = GST_STATE (element);
2385 next = GST_STATE_NEXT (element);
2386 old_pending = GST_STATE_PENDING (element);
2388 /* this is the (new) state we should go to. TARGET is the last state we set on
2390 if (state != GST_STATE_TARGET (element)) {
2391 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2392 "setting target state to %s", gst_element_state_get_name (state));
2393 GST_STATE_TARGET (element) = state;
2394 /* increment state cookie so that we can track each state change. We only do
2395 * this if this is actually a new state change. */
2396 element->state_cookie++;
2398 GST_STATE_PENDING (element) = state;
2400 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2401 "current %s, old_pending %s, next %s, old return %s",
2402 gst_element_state_get_name (current),
2403 gst_element_state_get_name (old_pending),
2404 gst_element_state_get_name (next),
2405 gst_element_state_change_return_get_name (old_ret));
2407 /* if the element was busy doing a state change, we just update the
2408 * target state, it'll get to it async then. */
2409 if (old_pending != GST_STATE_VOID_PENDING) {
2410 /* upwards state change will happen ASYNC */
2411 if (old_pending <= state)
2413 /* element is going to this state already */
2414 else if (next == state)
2416 /* element was performing an ASYNC upward state change and
2417 * we request to go downward again. Start from the next pending
2419 else if (next > state
2420 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
2424 next = GST_STATE_GET_NEXT (current, state);
2425 /* now we store the next state */
2426 GST_STATE_NEXT (element) = next;
2427 /* mark busy, we need to check that there is actually a state change
2428 * to be done else we could accidentally override SUCCESS/NO_PREROLL and
2429 * the default element change_state function has no way to know what the
2430 * old value was... could consider this a FIXME...*/
2431 if (current != next)
2432 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2434 transition = (GstStateChange) GST_STATE_TRANSITION (current, next);
2436 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2437 "%s: setting state from %s to %s",
2438 (next != state ? "intermediate" : "final"),
2439 gst_element_state_get_name (current), gst_element_state_get_name (next));
2441 /* now signal any waiters, they will error since the cookie was incremented */
2442 GST_STATE_BROADCAST (element);
2444 GST_OBJECT_UNLOCK (element);
2446 ret = gst_element_change_state (element, transition);
2448 GST_STATE_UNLOCK (element);
2450 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "returned %s",
2451 gst_element_state_change_return_get_name (ret));
2457 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2458 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2459 "element was busy with async state change");
2460 GST_OBJECT_UNLOCK (element);
2462 GST_STATE_UNLOCK (element);
2464 return GST_STATE_CHANGE_ASYNC;
2469 * gst_element_change_state:
2470 * @element: a #GstElement
2471 * @transition: the requested transition
2473 * Perform @transition on @element.
2475 * This function must be called with STATE_LOCK held and is mainly used
2478 * Returns: the #GstStateChangeReturn of the state transition.
2480 GstStateChangeReturn
2481 gst_element_change_state (GstElement * element, GstStateChange transition)
2483 GstElementClass *oclass;
2484 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2486 oclass = GST_ELEMENT_GET_CLASS (element);
2488 /* call the state change function so it can set the state */
2489 if (oclass->change_state)
2490 ret = (oclass->change_state) (element, transition);
2492 ret = GST_STATE_CHANGE_FAILURE;
2495 case GST_STATE_CHANGE_FAILURE:
2496 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2497 "have FAILURE change_state return");
2498 /* state change failure */
2499 gst_element_abort_state (element);
2501 case GST_STATE_CHANGE_ASYNC:
2505 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2506 "element will change state ASYNC");
2508 target = GST_STATE_TARGET (element);
2510 if (target > GST_STATE_READY)
2513 /* else we just continue the state change downwards */
2514 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2515 "forcing commit state %s <= %s",
2516 gst_element_state_get_name (target),
2517 gst_element_state_get_name (GST_STATE_READY));
2519 ret = gst_element_continue_state (element, GST_STATE_CHANGE_SUCCESS);
2522 case GST_STATE_CHANGE_SUCCESS:
2523 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2524 "element changed state SUCCESS");
2525 /* we can commit the state now which will proceeed to
2527 ret = gst_element_continue_state (element, ret);
2529 case GST_STATE_CHANGE_NO_PREROLL:
2530 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2531 "element changed state NO_PREROLL");
2532 /* we can commit the state now which will proceeed to
2534 ret = gst_element_continue_state (element, ret);
2537 goto invalid_return;
2540 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2545 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit async state change %d",
2553 GST_OBJECT_LOCK (element);
2554 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2555 g_critical ("%s: unknown return value %d from a state change function",
2556 GST_ELEMENT_NAME (element), ret);
2558 /* we are in error now */
2559 ret = GST_STATE_CHANGE_FAILURE;
2560 GST_STATE_RETURN (element) = ret;
2561 GST_OBJECT_UNLOCK (element);
2567 /* gst_iterator_fold functions for pads_activate
2568 * Stop the iterator if activating one pad failed. */
2570 activate_pads (const GValue * vpad, GValue * ret, gboolean * active)
2572 GstPad *pad = g_value_get_object (vpad);
2573 gboolean cont = TRUE;
2575 if (!(cont = gst_pad_set_active (pad, *active)))
2576 g_value_set_boolean (ret, FALSE);
2581 /* returns false on error or early cutout of the fold, true if all
2582 * pads in @iter were (de)activated successfully. */
2584 iterator_activate_fold_with_resync (GstIterator * iter,
2585 GstIteratorFoldFunction func, gpointer user_data)
2587 GstIteratorResult ires;
2590 /* no need to unset this later, it's just a boolean */
2591 g_value_init (&ret, G_TYPE_BOOLEAN);
2592 g_value_set_boolean (&ret, TRUE);
2595 ires = gst_iterator_fold (iter, func, &ret, user_data);
2597 case GST_ITERATOR_RESYNC:
2598 /* need to reset the result again */
2599 g_value_set_boolean (&ret, TRUE);
2600 gst_iterator_resync (iter);
2602 case GST_ITERATOR_DONE:
2603 /* all pads iterated, return collected value */
2606 /* iterator returned _ERROR or premature end with _OK,
2607 * mark an error and exit */
2608 g_value_set_boolean (&ret, FALSE);
2613 /* return collected value */
2614 return g_value_get_boolean (&ret);
2617 /* is called with STATE_LOCK
2619 * Pads are activated from source pads to sinkpads.
2622 gst_element_pads_activate (GstElement * element, gboolean active)
2627 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2628 "pads_activate with active %d", active);
2630 iter = gst_element_iterate_src_pads (element);
2632 iterator_activate_fold_with_resync (iter,
2633 (GstIteratorFoldFunction) activate_pads, &active);
2634 gst_iterator_free (iter);
2635 if (G_UNLIKELY (!res))
2638 iter = gst_element_iterate_sink_pads (element);
2640 iterator_activate_fold_with_resync (iter,
2641 (GstIteratorFoldFunction) activate_pads, &active);
2642 gst_iterator_free (iter);
2643 if (G_UNLIKELY (!res))
2646 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2647 "pads_activate successful");
2654 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2655 "source pads_activate failed");
2660 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2661 "sink pads_activate failed");
2666 /* is called with STATE_LOCK */
2667 static GstStateChangeReturn
2668 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2670 GstState state, next;
2671 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2673 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2675 state = (GstState) GST_STATE_TRANSITION_CURRENT (transition);
2676 next = GST_STATE_TRANSITION_NEXT (transition);
2678 /* if the element already is in the given state, we just return success */
2679 if (next == GST_STATE_VOID_PENDING || state == next)
2682 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2683 "default handler tries setting state from %s to %s (%04x)",
2684 gst_element_state_get_name (state),
2685 gst_element_state_get_name (next), transition);
2687 switch (transition) {
2688 case GST_STATE_CHANGE_NULL_TO_READY:
2690 case GST_STATE_CHANGE_READY_TO_PAUSED:
2691 if (!gst_element_pads_activate (element, TRUE)) {
2692 result = GST_STATE_CHANGE_FAILURE;
2695 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2697 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2699 case GST_STATE_CHANGE_PAUSED_TO_READY:
2700 case GST_STATE_CHANGE_READY_TO_NULL:
2701 /* deactivate pads in both cases, since they are activated on
2702 ready->paused but the element might not have made it to paused */
2703 if (!gst_element_pads_activate (element, FALSE)) {
2704 result = GST_STATE_CHANGE_FAILURE;
2708 /* this will catch real but unhandled state changes;
2709 * can only be caused by:
2710 * - a new state was added
2711 * - somehow the element was asked to jump across an intermediate state
2713 g_warning ("Unhandled state change from %s to %s",
2714 gst_element_state_get_name (state),
2715 gst_element_state_get_name (next));
2722 GST_OBJECT_LOCK (element);
2723 result = GST_STATE_RETURN (element);
2724 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2725 "element is already in the %s state",
2726 gst_element_state_get_name (state));
2727 GST_OBJECT_UNLOCK (element);
2734 * gst_element_get_factory:
2735 * @element: a #GstElement to request the element factory of.
2737 * Retrieves the factory that was used to create this element.
2739 * Returns: (transfer none): the #GstElementFactory used for creating this
2740 * element. no refcounting is needed.
2743 gst_element_get_factory (GstElement * element)
2745 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2747 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2751 gst_element_dispose (GObject * object)
2753 GstElement *element = GST_ELEMENT_CAST (object);
2757 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2759 if (GST_STATE (element) != GST_STATE_NULL)
2762 GST_CAT_DEBUG_OBJECT (GST_CAT_ELEMENT_PADS, element,
2763 "removing %d pads", g_list_length (element->pads));
2764 /* first we break all our links with the outside */
2765 while (element->pads && element->pads->data) {
2766 /* don't call _remove_pad with NULL */
2767 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2769 if (G_UNLIKELY (element->pads != NULL)) {
2770 g_critical ("could not remove pads from element %s",
2771 GST_STR_NULL (GST_OBJECT_NAME (object)));
2774 GST_OBJECT_LOCK (element);
2775 clock_p = &element->clock;
2776 bus_p = &element->bus;
2777 gst_object_replace ((GstObject **) clock_p, NULL);
2778 gst_object_replace ((GstObject **) bus_p, NULL);
2779 GST_OBJECT_UNLOCK (element);
2781 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2783 G_OBJECT_CLASS (parent_class)->dispose (object);
2792 is_locked = GST_ELEMENT_IS_LOCKED_STATE (element);
2794 ("\nTrying to dispose element %s, but it is in %s%s instead of the NULL"
2796 "You need to explicitly set elements to the NULL state before\n"
2797 "dropping the final reference, to allow them to clean up.\n"
2798 "This problem may also be caused by a refcounting bug in the\n"
2799 "application or some element.\n",
2800 GST_OBJECT_NAME (element),
2801 gst_element_state_get_name (GST_STATE (element)),
2802 is_locked ? " (locked)" : "");
2808 gst_element_finalize (GObject * object)
2810 GstElement *element = GST_ELEMENT_CAST (object);
2812 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2814 g_cond_free (element->state_cond);
2815 g_static_rec_mutex_free (&element->state_lock);
2817 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2819 G_OBJECT_CLASS (parent_class)->finalize (object);
2823 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2827 g_return_if_fail (GST_IS_ELEMENT (element));
2829 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2831 GST_OBJECT_LOCK (element);
2832 bus_p = &GST_ELEMENT_BUS (element);
2833 gst_object_replace ((GstObject **) bus_p, GST_OBJECT_CAST (bus));
2834 GST_OBJECT_UNLOCK (element);
2838 * gst_element_set_bus:
2839 * @element: a #GstElement to set the bus of.
2840 * @bus: (transfer none): the #GstBus to set.
2842 * Sets the bus of the element. Increases the refcount on the bus.
2843 * For internal use only, unless you're testing elements.
2848 gst_element_set_bus (GstElement * element, GstBus * bus)
2850 GstElementClass *oclass;
2852 g_return_if_fail (GST_IS_ELEMENT (element));
2854 oclass = GST_ELEMENT_GET_CLASS (element);
2856 if (oclass->set_bus)
2857 oclass->set_bus (element, bus);
2861 * gst_element_get_bus:
2862 * @element: a #GstElement to get the bus of.
2864 * Returns the bus of the element. Note that only a #GstPipeline will provide a
2865 * bus for the application.
2867 * Returns: (transfer full): the element's #GstBus. unref after usage.
2872 gst_element_get_bus (GstElement * element)
2874 GstBus *result = NULL;
2876 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2878 GST_OBJECT_LOCK (element);
2879 if ((result = GST_ELEMENT_BUS (element)))
2880 gst_object_ref (result);
2881 GST_OBJECT_UNLOCK (element);
2883 GST_CAT_DEBUG_OBJECT (GST_CAT_BUS, element, "got bus %" GST_PTR_FORMAT,