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 base class needed to construct an element that can be
29 * used in a GStreamer pipeline. As such, it is not a functional entity, and
30 * cannot do anything when placed in a pipeline.
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. Buffers 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 gst_element_provide_clock()
66 * method one can retrieve the clock provided by such an element.
67 * Not all elements require a clock to operate correctly. If
68 * gst_element_requires_clock() returns TRUE, a clock should be set on the
69 * element with gst_element_set_clock().
71 * Note that clock slection and distribution is normally handled by the
72 * toplevel #GstPipeline so the clock functions are only to be used in very
73 * specific situations.
76 #include "gst_private.h"
79 #include <gobject/gvaluecollector.h>
81 #include "gstelement.h"
83 #include "gstmarshal.h"
88 #include "gst-i18n-lib.h"
90 /* Element signals and args */
106 extern void __gst_element_details_clear (GstElementDetails * dp);
107 extern void __gst_element_details_copy (GstElementDetails * dest,
108 const GstElementDetails * src);
110 static void gst_element_class_init (GstElementClass * klass);
111 static void gst_element_init (GstElement * element);
112 static void gst_element_base_class_init (gpointer g_class);
113 static void gst_element_base_class_finalize (gpointer g_class);
115 static void gst_element_dispose (GObject * object);
116 static void gst_element_finalize (GObject * object);
118 static GstStateChangeReturn gst_element_change_state (GstElement * element,
119 GstStateChange transition);
120 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
121 GstStateChange transition);
122 static GstStateChangeReturn gst_element_change_state_func (GstElement * element,
123 GstStateChange transition);
124 static GstStateChangeReturn gst_element_get_state_func (GstElement * element,
125 GstState * state, GstState * pending, GstClockTime timeout);
126 static void gst_element_set_bus_func (GstElement * element, GstBus * bus);
128 #ifndef GST_DISABLE_LOADSAVE
129 static xmlNodePtr gst_element_save_thyself (GstObject * object,
131 static void gst_element_restore_thyself (GstObject * parent, xmlNodePtr self);
134 static GstObjectClass *parent_class = NULL;
135 static guint gst_element_signals[LAST_SIGNAL] = { 0 };
138 gst_element_get_type (void)
140 static GType gst_element_type = 0;
142 if (!gst_element_type) {
143 static const GTypeInfo element_info = {
144 sizeof (GstElementClass),
145 gst_element_base_class_init,
146 gst_element_base_class_finalize,
147 (GClassInitFunc) gst_element_class_init,
152 (GInstanceInitFunc) gst_element_init,
156 gst_element_type = g_type_register_static (GST_TYPE_OBJECT, "GstElement",
157 &element_info, G_TYPE_FLAG_ABSTRACT);
159 return gst_element_type;
163 gst_element_class_init (GstElementClass * klass)
165 GObjectClass *gobject_class;
166 GstObjectClass *gstobject_class;
168 gobject_class = (GObjectClass *) klass;
169 gstobject_class = (GstObjectClass *) klass;
171 parent_class = g_type_class_ref (GST_TYPE_OBJECT);
174 * GstElement::pad-added:
175 * @gstelement: the object which received the signal
176 * @new_pad: the pad that has been added
178 * a new #GstPad has been added to the element.
180 gst_element_signals[NEW_PAD] =
181 g_signal_new ("pad-added", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
182 G_STRUCT_OFFSET (GstElementClass, pad_added), NULL, NULL,
183 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, G_TYPE_OBJECT);
185 * GstElement::pad-removed:
186 * @gstelement: the object which received the signal
187 * @old_pad: the pad that has been removed
189 * a #GstPad has been removed from the element
191 gst_element_signals[PAD_REMOVED] =
192 g_signal_new ("pad-removed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
193 G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
194 gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, G_TYPE_OBJECT);
196 * GstElement::no-more-pads:
197 * @gstelement: the object which received the signal
199 * This signals that the element will not generate more dynamic pads.
201 gst_element_signals[NO_MORE_PADS] =
202 g_signal_new ("no-more-pads", G_TYPE_FROM_CLASS (klass),
203 G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstElementClass, no_more_pads), NULL,
204 NULL, gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
206 gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_element_dispose);
207 gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_element_finalize);
209 #ifndef GST_DISABLE_LOADSAVE
210 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
211 gstobject_class->restore_thyself =
212 GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
215 klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state_func);
216 klass->get_state = GST_DEBUG_FUNCPTR (gst_element_get_state_func);
217 klass->set_bus = GST_DEBUG_FUNCPTR (gst_element_set_bus_func);
218 klass->numpadtemplates = 0;
220 klass->elementfactory = NULL;
224 gst_element_base_class_init (gpointer g_class)
226 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
228 memset (&element_class->details, 0, sizeof (GstElementDetails));
229 element_class->padtemplates = NULL;
233 gst_element_base_class_finalize (gpointer g_class)
235 GstElementClass *klass = GST_ELEMENT_CLASS (g_class);
237 g_list_foreach (klass->padtemplates, (GFunc) gst_object_unref, NULL);
238 g_list_free (klass->padtemplates);
239 __gst_element_details_clear (&klass->details);
243 gst_element_init (GstElement * element)
245 GST_STATE (element) = GST_STATE_NULL;
246 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
247 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
248 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
250 element->state_lock = g_new0 (GStaticRecMutex, 1);
251 g_static_rec_mutex_init (element->state_lock);
252 element->state_cond = g_cond_new ();
256 * gst_element_default_error:
257 * @object: a #GObject that signalled the error.
258 * @orig: the #GstObject that initiated the error.
259 * @error: the GError.
260 * @debug: an additional debug information string, or NULL.
262 * A default error signal callback to attach to an element.
263 * The user data passed to the g_signal_connect is ignored.
265 * The default handler will simply print the error string using g_print.
270 gst_element_default_error (GObject * object, GstObject * source, GError * error,
273 gchar *name = gst_object_get_path_string (source);
275 g_print (_("ERROR: from element %s: %s\n"), name, error->message);
277 g_print (_("Additional debug info:\n%s\n"), debug);
283 * gst_element_release_request_pad:
284 * @element: a #GstElement to release the request pad of.
285 * @pad: the #GstPad to release.
287 * Makes the element free the previously requested pad as obtained
288 * with gst_element_get_request_pad().
293 gst_element_release_request_pad (GstElement * element, GstPad * pad)
295 GstElementClass *oclass;
297 g_return_if_fail (GST_IS_ELEMENT (element));
298 g_return_if_fail (GST_IS_PAD (pad));
300 oclass = GST_ELEMENT_GET_CLASS (element);
302 if (oclass->release_pad)
303 (oclass->release_pad) (element, pad);
305 gst_element_remove_pad (element, pad);
309 * gst_element_requires_clock:
310 * @element: a #GstElement to query
312 * Query if the element requires a clock.
314 * Returns: TRUE if the element requires a clock
319 gst_element_requires_clock (GstElement * element)
323 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
325 result = (GST_ELEMENT_GET_CLASS (element)->set_clock != NULL);
331 * gst_element_provides_clock:
332 * @element: a #GstElement to query
334 * Query if the element provides a clock.
336 * Returns: TRUE if the element provides a clock
341 gst_element_provides_clock (GstElement * element)
345 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
347 result = (GST_ELEMENT_GET_CLASS (element)->provide_clock != NULL);
353 * gst_element_provide_clock:
354 * @element: a #GstElement to query
356 * Get the clock provided by the given element.
358 * Returns: the GstClock provided by the element or NULL
359 * if no clock could be provided. Unref after usage.
364 gst_element_provide_clock (GstElement * element)
366 GstClock *result = NULL;
367 GstElementClass *oclass;
369 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
371 oclass = GST_ELEMENT_GET_CLASS (element);
373 if (oclass->provide_clock)
374 result = oclass->provide_clock (element);
380 * gst_element_set_clock:
381 * @element: a #GstElement to set the clock for.
382 * @clock: the #GstClock to set for the element.
384 * Sets the clock for the element. This function increases the
385 * refcount on the clock. Any previously set clock on the object
391 gst_element_set_clock (GstElement * element, GstClock * clock)
393 GstElementClass *oclass;
395 g_return_if_fail (GST_IS_ELEMENT (element));
397 oclass = GST_ELEMENT_GET_CLASS (element);
399 if (oclass->set_clock)
400 oclass->set_clock (element, clock);
403 gst_object_replace ((GstObject **) & element->clock, (GstObject *) clock);
404 GST_UNLOCK (element);
408 * gst_element_get_clock:
409 * @element: a #GstElement to get the clock of.
411 * Gets the currently configured clock of the element.
413 * Returns: the #GstClock of the element. unref after usage.
418 gst_element_get_clock (GstElement * element)
422 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
425 if ((result = element->clock))
426 gst_object_ref (result);
427 GST_UNLOCK (element);
433 * gst_element_set_base_time:
434 * @element: a #GstElement.
435 * @time: the base time to set.
437 * Set the base time of an element. See @gst_element_get_base_time().
442 gst_element_set_base_time (GstElement * element, GstClockTime time)
444 g_return_if_fail (GST_IS_ELEMENT (element));
447 element->base_time = time;
448 GST_UNLOCK (element);
452 * gst_element_get_base_time:
453 * @element: a #GstElement.
455 * Returns the base time of the element. The base time is the
456 * absolute time of the clock when this element was last put to
457 * PLAYING. Substracting the base time from the clock time gives
458 * the stream time of the element.
460 * Returns: the base time of the element.
465 gst_element_get_base_time (GstElement * element)
469 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_CLOCK_TIME_NONE);
472 result = element->base_time;
473 GST_UNLOCK (element);
478 #ifndef GST_DISABLE_INDEX
480 * gst_element_is_indexable:
481 * @element: a #GstElement.
483 * Queries if the element can be indexed.
485 * Returns: TRUE if the element can be indexed.
490 gst_element_is_indexable (GstElement * element)
494 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
496 result = (GST_ELEMENT_GET_CLASS (element)->set_index != NULL);
502 * gst_element_set_index:
503 * @element: a #GstElement.
504 * @index: a #GstIndex.
506 * Set the specified GstIndex on the element. The refcount of the index
507 * will be increased, any previously set index is unreffed.
512 gst_element_set_index (GstElement * element, GstIndex * index)
514 GstElementClass *oclass;
516 g_return_if_fail (GST_IS_ELEMENT (element));
517 g_return_if_fail (GST_IS_INDEX (index));
519 oclass = GST_ELEMENT_GET_CLASS (element);
521 if (oclass->set_index)
522 oclass->set_index (element, index);
526 * gst_element_get_index:
527 * @element: a #GstElement.
529 * Gets the index from the element.
531 * Returns: a #GstIndex or NULL when no index was set on the
532 * element. unref after usage.
537 gst_element_get_index (GstElement * element)
539 GstElementClass *oclass;
541 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
543 oclass = GST_ELEMENT_GET_CLASS (element);
545 if (oclass->get_index)
546 return oclass->get_index (element);
553 * gst_element_add_pad:
554 * @element: a #GstElement to add the pad to.
555 * @pad: the #GstPad to add to the element.
557 * Adds a pad (link point) to @element. @pad's parent will be set to @element;
558 * see gst_object_set_parent() for refcounting information.
560 * Pads are not automatically activated so elements should perform the needed
561 * steps to activate the pad in case this pad is added in the PAUSED or PLAYING
564 * The pad and the element should be unlocked when calling this function.
566 * Returns: TRUE if the pad could be added. This function can fail when
567 * passing bad arguments or when a pad with the same name already existed.
572 gst_element_add_pad (GstElement * element, GstPad * pad)
576 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
577 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
579 /* locking pad to look at the name */
581 pad_name = g_strdup (GST_PAD_NAME (pad));
582 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "adding pad '%s'",
583 GST_STR_NULL (pad_name));
586 /* then check to see if there's already a pad by that name here */
588 if (G_UNLIKELY (!gst_object_check_uniqueness (element->pads, pad_name)))
591 /* try to set the pad's parent */
592 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (pad),
593 GST_OBJECT_CAST (element))))
598 /* add it to the list */
599 switch (gst_pad_get_direction (pad)) {
601 element->srcpads = g_list_prepend (element->srcpads, pad);
602 element->numsrcpads++;
605 element->sinkpads = g_list_prepend (element->sinkpads, pad);
606 element->numsinkpads++;
611 element->pads = g_list_prepend (element->pads, pad);
613 element->pads_cookie++;
614 GST_UNLOCK (element);
616 /* emit the NEW_PAD signal */
617 g_signal_emit (G_OBJECT (element), gst_element_signals[NEW_PAD], 0, pad);
624 g_critical ("Padname %s is not unique in element %s, not adding",
625 pad_name, GST_ELEMENT_NAME (element));
626 GST_UNLOCK (element);
633 ("Pad %s already has parent when trying to add to element %s",
634 pad_name, GST_ELEMENT_NAME (element));
635 GST_UNLOCK (element);
643 ("Trying to add pad %s to element %s, but it has no direction",
644 GST_OBJECT_NAME (pad), GST_ELEMENT_NAME (element));
646 GST_UNLOCK (element);
652 * gst_element_remove_pad:
653 * @element: a #GstElement to remove pad from.
654 * @pad: the #GstPad to remove from the element.
656 * Removes @pad from @element. @pad will be destroyed if it has not been
657 * referenced elsewhere.
659 * Returns: TRUE if the pad could be removed. Can return FALSE if the
660 * pad is not belonging to the provided element or when wrong parameters
661 * are passed to this function.
666 gst_element_remove_pad (GstElement * element, GstPad * pad)
670 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
671 g_return_val_if_fail (GST_IS_PAD (pad), FALSE);
673 /* locking pad to look at the name and parent */
675 GST_CAT_INFO_OBJECT (GST_CAT_ELEMENT_PADS, element, "removing pad '%s'",
676 GST_STR_NULL (GST_PAD_NAME (pad)));
678 if (G_UNLIKELY (GST_PAD_PARENT (pad) != element))
683 if ((peer = gst_pad_get_peer (pad))) {
684 /* window for MT unsafeness, someone else could unlink here
685 * and then we call unlink with wrong pads. The unlink
686 * function would catch this and safely return failed. */
687 if (GST_PAD_IS_SRC (pad))
688 gst_pad_unlink (pad, peer);
690 gst_pad_unlink (peer, pad);
692 gst_object_unref (peer);
696 /* remove it from the list */
697 switch (gst_pad_get_direction (pad)) {
699 element->srcpads = g_list_remove (element->srcpads, pad);
700 element->numsrcpads--;
703 element->sinkpads = g_list_remove (element->sinkpads, pad);
704 element->numsinkpads--;
707 g_critical ("Removing pad without direction???");
710 element->pads = g_list_remove (element->pads, pad);
712 element->pads_cookie++;
713 GST_UNLOCK (element);
715 g_signal_emit (G_OBJECT (element), gst_element_signals[PAD_REMOVED], 0, pad);
717 gst_object_unparent (GST_OBJECT (pad));
723 /* FIXME, locking order? */
725 g_critical ("Padname %s:%s does not belong to element %s when removing",
726 GST_ELEMENT_NAME (GST_PAD_PARENT (pad)), GST_PAD_NAME (pad),
727 GST_ELEMENT_NAME (element));
728 GST_UNLOCK (element);
735 * gst_element_no_more_pads:
736 * @element: a #GstElement
738 * Use this function to signal that the element does not expect any more pads
739 * to show up in the current pipeline. This function should be called whenever
740 * pads have been added by the element itself. Elements with GST_PAD_SOMETIMES
741 * pad templates use this in combination with autopluggers to figure out that
742 * the element is done initializing its pads.
747 gst_element_no_more_pads (GstElement * element)
749 g_return_if_fail (GST_IS_ELEMENT (element));
751 g_signal_emit (element, gst_element_signals[NO_MORE_PADS], 0);
755 pad_compare_name (GstPad * pad1, const gchar * name)
760 result = strcmp (GST_PAD_NAME (pad1), name);
767 * gst_element_get_static_pad:
768 * @element: a #GstElement to find a static pad of.
769 * @name: the name of the static #GstPad to retrieve.
771 * Retrieves a pad from @element by name. This version only retrieves
772 * already-existing (i.e. 'static') pads.
774 * Returns: the requested #GstPad if found, otherwise NULL. unref after
780 gst_element_get_static_pad (GstElement * element, const gchar * name)
783 GstPad *result = NULL;
785 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
786 g_return_val_if_fail (name != NULL, NULL);
790 g_list_find_custom (element->pads, name, (GCompareFunc) pad_compare_name);
792 result = GST_PAD_CAST (find->data);
793 gst_object_ref (result);
796 if (result == NULL) {
797 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "no such pad '%s' in element \"%s\"",
798 name, GST_ELEMENT_NAME (element));
800 GST_CAT_INFO (GST_CAT_ELEMENT_PADS, "found pad %s:%s",
801 GST_ELEMENT_NAME (element), name);
803 GST_UNLOCK (element);
809 gst_element_request_pad (GstElement * element, GstPadTemplate * templ,
812 GstPad *newpad = NULL;
813 GstElementClass *oclass;
815 oclass = GST_ELEMENT_GET_CLASS (element);
817 if (oclass->request_new_pad)
818 newpad = (oclass->request_new_pad) (element, templ, name);
821 gst_object_ref (newpad);
827 * gst_element_get_request_pad:
828 * @element: a #GstElement to find a request pad of.
829 * @name: the name of the request #GstPad to retrieve.
831 * Retrieves a pad from the element by name. This version only retrieves
834 * Returns: requested #GstPad if found, otherwise NULL. Unref after usage.
837 gst_element_get_request_pad (GstElement * element, const gchar * name)
839 GstPadTemplate *templ = NULL;
841 const gchar *req_name = NULL;
842 gboolean templ_found = FALSE;
846 gchar *str, *endptr = NULL;
847 GstElementClass *class;
849 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
850 g_return_val_if_fail (name != NULL, NULL);
852 class = GST_ELEMENT_GET_CLASS (element);
854 if (strstr (name, "%")) {
855 templ = gst_element_class_get_pad_template (class, name);
860 list = gst_element_class_get_pad_template_list (class);
861 while (!templ_found && list) {
862 templ = (GstPadTemplate *) list->data;
863 if (templ->presence == GST_PAD_REQUEST) {
864 /* Because of sanity checks in gst_pad_template_new(), we know that %s
865 and %d, occurring at the end of the name_template, are the only
867 GST_CAT_DEBUG (GST_CAT_PADS, "comparing %s to %s", name,
868 templ->name_template);
869 if ((str = strchr (templ->name_template, '%'))
870 && strncmp (templ->name_template, name,
871 str - templ->name_template) == 0
872 && strlen (name) > str - templ->name_template) {
873 data = name + (str - templ->name_template);
874 if (*(str + 1) == 'd') {
876 n = (gint) strtol (data, &endptr, 10);
877 if (endptr && *endptr == '\0') {
897 pad = gst_element_request_pad (element, templ, req_name);
903 * gst_element_get_pad:
904 * @element: a #GstElement.
905 * @name: the name of the pad to retrieve.
907 * Retrieves a pad from @element by name. Tries gst_element_get_static_pad()
908 * first, then gst_element_get_request_pad().
910 * Returns: the #GstPad if found, otherwise %NULL. Unref after usage.
913 gst_element_get_pad (GstElement * element, const gchar * name)
917 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
918 g_return_val_if_fail (name != NULL, NULL);
920 pad = gst_element_get_static_pad (element, name);
922 pad = gst_element_get_request_pad (element, name);
927 static GstIteratorItem
928 iterate_pad (GstIterator * it, GstPad * pad)
930 gst_object_ref (pad);
931 return GST_ITERATOR_ITEM_PASS;
935 gst_element_iterate_pad_list (GstElement * element, GList ** padlist)
940 gst_object_ref (element);
941 result = gst_iterator_new_list (GST_TYPE_PAD,
942 GST_GET_LOCK (element),
943 &element->pads_cookie,
946 (GstIteratorItemFunction) iterate_pad,
947 (GstIteratorDisposeFunction) gst_object_unref);
948 GST_UNLOCK (element);
954 * gst_element_iterate_pads:
955 * @element: a #GstElement to iterate pads of.
957 * Retrieves an iterattor of @element's pads. The iterator should
958 * be freed after usage.
960 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
965 gst_element_iterate_pads (GstElement * element)
967 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
969 return gst_element_iterate_pad_list (element, &element->pads);
973 * gst_element_iterate_src_pads:
974 * @element: a #GstElement.
976 * Retrieves an iterator of @element's source pads.
978 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
983 gst_element_iterate_src_pads (GstElement * element)
985 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
987 return gst_element_iterate_pad_list (element, &element->srcpads);
991 * gst_element_iterate_sink_pads:
992 * @element: a #GstElement.
994 * Retrieves an iterator of @element's sink pads.
996 * Returns: the #GstIterator of #GstPad. Unref each pad after use.
1001 gst_element_iterate_sink_pads (GstElement * element)
1003 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1005 return gst_element_iterate_pad_list (element, &element->sinkpads);
1009 * gst_element_class_add_pad_template:
1010 * @klass: the #GstElementClass to add the pad template to.
1011 * @templ: a #GstPadTemplate to add to the element class.
1013 * Adds a padtemplate to an element class. This is mainly used in the _base_init
1014 * functions of classes.
1017 gst_element_class_add_pad_template (GstElementClass * klass,
1018 GstPadTemplate * templ)
1020 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1021 g_return_if_fail (GST_IS_PAD_TEMPLATE (templ));
1023 /* avoid registering pad templates with the same name */
1024 g_return_if_fail (gst_element_class_get_pad_template (klass,
1025 templ->name_template) == NULL);
1027 klass->padtemplates = g_list_append (klass->padtemplates,
1028 gst_object_ref (templ));
1029 klass->numpadtemplates++;
1033 * gst_element_class_set_details:
1034 * @klass: class to set details for
1035 * @details: details to set
1037 * Sets the detailed information for a #GstElementClass.
1038 * <note>This function is for use in _base_init functions only.</note>
1041 gst_element_class_set_details (GstElementClass * klass,
1042 const GstElementDetails * details)
1044 g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
1045 g_return_if_fail (GST_IS_ELEMENT_DETAILS (details));
1047 __gst_element_details_copy (&klass->details, details);
1051 * gst_element_class_get_pad_template_list:
1052 * @element_class: a #GstElementClass to get pad templates of.
1054 * Retrieves a list of the pad templates associated with @element_class. The
1055 * list must not be modified by the calling code.
1056 * <note>If you use this function in the #GInstanceInitFunc of an object class
1057 * that has subclasses, make sure to pass the g_class parameter of the
1058 * #GInstanceInitFunc here.</note>
1060 * Returns: the #GList of padtemplates.
1063 gst_element_class_get_pad_template_list (GstElementClass * element_class)
1065 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1067 return element_class->padtemplates;
1071 * gst_element_class_get_pad_template:
1072 * @element_class: a #GstElementClass to get the pad template of.
1073 * @name: the name of the #GstPadTemplate to get.
1075 * Retrieves a padtemplate from @element_class with the given name.
1076 * <note>If you use this function in the #GInstanceInitFunc of an object class
1077 * that has subclasses, make sure to pass the g_class parameter of the
1078 * #GInstanceInitFunc here.</note>
1080 * Returns: the #GstPadTemplate with the given name, or NULL if none was found.
1081 * No unreferencing is necessary.
1084 gst_element_class_get_pad_template (GstElementClass * element_class,
1089 g_return_val_if_fail (GST_IS_ELEMENT_CLASS (element_class), NULL);
1090 g_return_val_if_fail (name != NULL, NULL);
1092 padlist = gst_element_class_get_pad_template_list (element_class);
1095 GstPadTemplate *padtempl = (GstPadTemplate *) padlist->data;
1097 if (strcmp (padtempl->name_template, name) == 0)
1100 padlist = g_list_next (padlist);
1107 gst_element_get_random_pad (GstElement * element, GstPadDirection dir)
1109 GstPad *result = NULL;
1112 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "getting a random pad");
1117 pads = element->srcpads;
1121 pads = element->sinkpads;
1124 goto wrong_direction;
1126 for (; pads; pads = g_list_next (pads)) {
1127 GstPad *pad = GST_PAD (pads->data);
1130 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "checking pad %s:%s",
1131 GST_DEBUG_PAD_NAME (pad));
1133 if (GST_PAD_IS_LINKED (pad)) {
1138 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "pad %s:%s is not linked",
1139 GST_DEBUG_PAD_NAME (pad));
1144 gst_object_ref (result);
1146 GST_UNLOCK (element);
1150 /* ERROR handling */
1153 g_warning ("unknown pad direction %d", dir);
1159 * gst_element_send_event:
1160 * @element: a #GstElement to send the event to.
1161 * @event: the #GstEvent to send to the element.
1163 * Sends an event to an element. If the element doesn't
1164 * implement an event handler, the event will be forwarded
1165 * to a random sink pad. This function takes owership of the
1166 * provided event so you should _ref it if you want to reuse
1167 * the event after this call.
1169 * Returns: TRUE if the event was handled.
1174 gst_element_send_event (GstElement * element, GstEvent * event)
1176 GstElementClass *oclass;
1177 gboolean result = FALSE;
1179 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1180 g_return_val_if_fail (event != NULL, FALSE);
1182 oclass = GST_ELEMENT_GET_CLASS (element);
1184 if (oclass->send_event) {
1185 result = oclass->send_event (element, event);
1187 GstPad *pad = gst_element_get_random_pad (element, GST_PAD_SINK);
1190 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS,
1191 "pushing event to random pad %s:%s", GST_DEBUG_PAD_NAME (pad));
1193 result = gst_pad_push_event (pad, event);
1194 gst_object_unref (pad);
1196 GST_CAT_DEBUG (GST_CAT_ELEMENT_PADS, "can't send event on element %s",
1197 GST_ELEMENT_NAME (element));
1205 * @element: a #GstElement to send the event to.
1206 * @rate: The new playback rate
1207 * @format: The format of the seek values
1208 * @flags: The optional seek flags.
1209 * @cur_type: The type and flags for the new current position
1210 * @cur: The value of the new current position
1211 * @stop_type: The type and flags for the new stop position
1212 * @stop: The value of the new stop position
1214 * Sends a seek event to an element.
1216 * Returns: %TRUE if the event was handled.
1221 gst_element_seek (GstElement * element, gdouble rate, GstFormat format,
1222 GstSeekFlags flags, GstSeekType cur_type, gint64 cur,
1223 GstSeekType stop_type, gint64 stop)
1228 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1231 gst_event_new_seek (rate, format, flags, cur_type, cur, stop_type, stop);
1232 result = gst_element_send_event (element, event);
1238 * gst_element_get_query_types:
1239 * @element: a #GstElement to query
1241 * Get an array of query types from the element.
1242 * If the element doesn't implement a query types function,
1243 * the query will be forwarded to a random sink pad.
1245 * Returns: An array of #GstQueryType elements that should not
1246 * be freed or modified.
1250 const GstQueryType *
1251 gst_element_get_query_types (GstElement * element)
1253 GstElementClass *oclass;
1254 const GstQueryType *result = NULL;
1256 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
1258 oclass = GST_ELEMENT_GET_CLASS (element);
1260 if (oclass->get_query_types) {
1261 result = oclass->get_query_types (element);
1263 GstPad *pad = gst_element_get_random_pad (element, GST_PAD_SINK);
1266 GstPad *peer = gst_pad_get_peer (pad);
1269 result = gst_pad_get_query_types (peer);
1271 gst_object_unref (peer);
1273 gst_object_unref (pad);
1280 * gst_element_query:
1281 * @element: a #GstElement to perform the query on.
1282 * @query: the #GstQuery.
1284 * Performs a query on the given element. If the format is set
1285 * to GST_FORMAT_DEFAULT and this function returns TRUE, the
1286 * format pointer will hold the default format.
1287 * For element that don't implement a query handler, this function
1288 * forwards the query to a random usable sinkpad of this element.
1290 * Returns: TRUE if the query could be performed.
1295 gst_element_query (GstElement * element, GstQuery * query)
1297 GstElementClass *oclass;
1298 gboolean result = FALSE;
1300 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1301 g_return_val_if_fail (query != NULL, FALSE);
1303 oclass = GST_ELEMENT_GET_CLASS (element);
1305 if (oclass->query) {
1306 result = oclass->query (element, query);
1308 GstPad *pad = gst_element_get_random_pad (element, GST_PAD_SRC);
1311 result = gst_pad_query (pad, query);
1313 gst_object_unref (pad);
1315 pad = gst_element_get_random_pad (element, GST_PAD_SINK);
1317 GstPad *peer = gst_pad_get_peer (pad);
1320 result = gst_pad_query (peer, query);
1322 gst_object_unref (peer);
1324 gst_object_unref (pad);
1332 * gst_element_post_message:
1333 * @element: a #GstElement posting the message
1334 * @message: a #GstMessage to post
1336 * Post a message on the element's #GstBus. This function takes ownership of the
1337 * message; if you want to access the message after this call, you should add an
1338 * additional reference before calling.
1340 * Returns: TRUE if the message was successfully posted.
1345 gst_element_post_message (GstElement * element, GstMessage * message)
1348 gboolean result = FALSE;
1350 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1351 g_return_val_if_fail (message != NULL, FALSE);
1356 if (G_UNLIKELY (bus == NULL))
1359 gst_object_ref (bus);
1360 GST_UNLOCK (element);
1362 result = gst_bus_post (bus, message);
1363 gst_object_unref (bus);
1369 GST_DEBUG ("not posting message %p: no bus", message);
1370 GST_UNLOCK (element);
1371 gst_message_unref (message);
1377 * _gst_element_error_printf:
1378 * @format: the printf-like format to use, or NULL
1380 * This function is only used internally by the #gst_element_error macro.
1382 * Returns: a newly allocated string, or NULL if the format was NULL or ""
1387 _gst_element_error_printf (const gchar * format, ...)
1397 va_start (args, format);
1398 buffer = g_strdup_vprintf (format, args);
1404 * gst_element_message_full:
1405 * @element: a #GstElement to send message from
1406 * @type: the #GstMessageType
1407 * @domain: the GStreamer GError domain this message belongs to
1408 * @code: the GError code belonging to the domain
1409 * @text: an allocated text string to be used as a replacement for the
1410 * default message connected to code, or NULL
1411 * @debug: an allocated debug message to be used as a replacement for the
1412 * default debugging information, or NULL
1413 * @file: the source code file where the error was generated
1414 * @function: the source code function where the error was generated
1415 * @line: the source code line where the error was generated
1417 * Post an error or warning message on the bus from inside an element.
1421 void gst_element_message_full
1422 (GstElement * element, GstMessageType type,
1423 GQuark domain, gint code, gchar * text,
1424 gchar * debug, const gchar * file, const gchar * function, gint line)
1426 GError *gerror = NULL;
1430 GstMessage *message = NULL;
1433 GST_DEBUG ("start");
1434 g_return_if_fail (GST_IS_ELEMENT (element));
1435 g_return_if_fail ((type == GST_MESSAGE_ERROR) ||
1436 (type == GST_MESSAGE_WARNING));
1438 /* check if we send the given text or the default error text */
1439 if ((text == NULL) || (text[0] == 0)) {
1440 /* text could have come from g_strdup_printf (""); */
1442 sent_text = gst_error_get_message (domain, code);
1446 /* construct a sent_debug with extra information from source */
1447 if ((debug == NULL) || (debug[0] == 0)) {
1448 /* debug could have come from g_strdup_printf (""); */
1451 name = gst_object_get_path_string (GST_OBJECT (element));
1452 sent_debug = g_strdup_printf ("%s(%d): %s: %s:\n%s",
1453 file, line, function, name, debug ? debug : "");
1458 /* create gerror and post message */
1459 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posting message: %s",
1461 gerror = g_error_new_literal (domain, code, sent_text);
1463 if (type == GST_MESSAGE_ERROR) {
1464 message = gst_message_new_error (GST_OBJECT (element), gerror, sent_debug);
1465 } else if (type == GST_MESSAGE_WARNING) {
1466 message = gst_message_new_warning (GST_OBJECT (element), gerror,
1469 g_assert_not_reached ();
1471 gst_element_post_message (element, message);
1473 GST_CAT_INFO_OBJECT (GST_CAT_ERROR_SYSTEM, element, "posted message: %s",
1477 g_error_free (gerror);
1478 g_free (sent_debug);
1483 * gst_element_is_locked_state:
1484 * @element: a #GstElement.
1486 * Checks if the state of an element is locked.
1487 * If the state of an element is locked, state changes of the parent don't
1488 * affect the element.
1489 * This way you can leave currently unused elements inside bins. Just lock their
1490 * state before changing the state from #GST_STATE_NULL.
1492 * Returns: TRUE, if the element's state is locked.
1497 gst_element_is_locked_state (GstElement * element)
1501 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1504 result = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1505 GST_UNLOCK (element);
1511 * gst_element_set_locked_state:
1512 * @element: a #GstElement
1513 * @locked_state: TRUE to lock the element's state
1515 * Locks the state of an element, so state changes of the parent don't affect
1516 * this element anymore.
1518 * Returns: TRUE if the state was changed, FALSE if bad params were given or
1519 * the element was already in the correct state.
1524 gst_element_set_locked_state (GstElement * element, gboolean locked_state)
1528 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1531 old = GST_OBJECT_FLAG_IS_SET (element, GST_ELEMENT_LOCKED_STATE);
1533 if (G_UNLIKELY (old == locked_state))
1537 GST_CAT_DEBUG (GST_CAT_STATES, "locking state of element %s",
1538 GST_ELEMENT_NAME (element));
1539 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_LOCKED_STATE);
1541 GST_CAT_DEBUG (GST_CAT_STATES, "unlocking state of element %s",
1542 GST_ELEMENT_NAME (element));
1543 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_LOCKED_STATE);
1545 GST_UNLOCK (element);
1550 GST_UNLOCK (element);
1556 * gst_element_sync_state_with_parent:
1557 * @element: a #GstElement.
1559 * Tries to change the state of the element to the same as its parent.
1560 * If this function returns FALSE, the state of element is undefined.
1562 * Returns: TRUE, if the element's state could be synced to the parent's state.
1567 gst_element_sync_state_with_parent (GstElement * element)
1571 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
1573 if ((parent = GST_ELEMENT_CAST (gst_element_get_parent (element)))) {
1574 GstState parent_current, parent_pending;
1575 GstStateChangeReturn ret;
1577 GST_STATE_LOCK (parent);
1578 parent_current = GST_STATE (parent);
1579 parent_pending = GST_STATE_PENDING (parent);
1580 GST_STATE_UNLOCK (parent);
1582 GST_CAT_DEBUG (GST_CAT_STATES,
1583 "syncing state of element %s (%s) to %s (%s, %s)",
1584 GST_ELEMENT_NAME (element),
1585 gst_element_state_get_name (GST_STATE (element)),
1586 GST_ELEMENT_NAME (parent), gst_element_state_get_name (parent_current),
1587 gst_element_state_get_name (parent_pending));
1589 ret = gst_element_set_state (element, parent_current);
1590 if (ret == GST_STATE_CHANGE_FAILURE)
1593 gst_object_unref (parent);
1607 static GstStateChangeReturn
1608 gst_element_get_state_func (GstElement * element,
1609 GstState * state, GstState * pending, GstClockTime timeout)
1611 GstStateChangeReturn ret = GST_STATE_CHANGE_FAILURE;
1612 GstState old_pending;
1614 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "getting state");
1616 GST_STATE_LOCK (element);
1617 ret = GST_STATE_RETURN (element);
1619 /* we got an error, report immediatly */
1620 if (ret == GST_STATE_CHANGE_FAILURE)
1623 /* we got no_preroll, report immediatly */
1624 if (ret == GST_STATE_CHANGE_NO_PREROLL)
1627 /* no need to wait async if we are not async */
1628 if (ret != GST_STATE_CHANGE_ASYNC)
1631 old_pending = GST_STATE_PENDING (element);
1632 if (old_pending != GST_STATE_VOID_PENDING) {
1633 GTimeVal *timeval, abstimeout;
1635 if (timeout != GST_CLOCK_TIME_NONE) {
1636 glong add = timeout / 1000;
1641 /* make timeout absolute */
1642 g_get_current_time (&abstimeout);
1643 g_time_val_add (&abstimeout, add);
1644 timeval = &abstimeout;
1648 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1649 "waiting for element to commit state");
1650 /* we have a pending state change, wait for it to complete */
1651 if (!GST_STATE_TIMED_WAIT (element, timeval)) {
1652 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "timed out");
1653 /* timeout triggered */
1654 ret = GST_STATE_CHANGE_ASYNC;
1656 /* could be success or failure */
1657 if (old_pending == GST_STATE (element)) {
1658 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got success");
1659 ret = GST_STATE_CHANGE_SUCCESS;
1661 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "got failure");
1662 ret = GST_STATE_CHANGE_FAILURE;
1666 /* if nothing is pending anymore we can return SUCCESS */
1667 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING) {
1668 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "nothing pending");
1669 ret = GST_STATE_CHANGE_SUCCESS;
1674 *state = GST_STATE (element);
1676 *pending = GST_STATE_PENDING (element);
1678 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1679 "state current: %s, pending: %s, result: %d",
1680 gst_element_state_get_name (GST_STATE (element)),
1681 gst_element_state_get_name (GST_STATE_PENDING (element)), ret);
1683 GST_STATE_UNLOCK (element);
1689 * gst_element_get_state:
1690 * @element: a #GstElement to get the state of.
1691 * @state: a pointer to #GstState to hold the state. Can be NULL.
1692 * @pending: a pointer to #GstState to hold the pending state.
1694 * @timeout: a #GstClockTime to specify the timeout for an async
1695 * state change or GST_CLOCK_TIME_NONE for infinite timeout.
1697 * Gets the state of the element.
1699 * For elements that performed an ASYNC state change, as reported by
1700 * #gst_element_set_state(), this function will block up to the
1701 * specified timeout value for the state change to complete.
1702 * If the element completes the state change or goes into
1703 * an error, this function returns immediatly with a return value of
1704 * GST_STATE_CHANGE_SUCCESS or GST_STATE_CHANGE_FAILURE respectively.
1706 * For elements that did not return ASYNC, this function returns the
1707 * current and pending state immediatly.
1709 * Returns: GST_STATE_CHANGE_SUCCESS if the element has no more pending state and
1710 * the last state change succeeded, GST_STATE_CHANGE_ASYNC
1711 * if the element is still performing a state change or
1712 * GST_STATE_CHANGE_FAILURE if the last state change failed.
1716 GstStateChangeReturn
1717 gst_element_get_state (GstElement * element,
1718 GstState * state, GstState * pending, GstClockTime timeout)
1720 GstElementClass *oclass;
1721 GstStateChangeReturn result = GST_STATE_CHANGE_FAILURE;
1723 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
1725 oclass = GST_ELEMENT_GET_CLASS (element);
1727 if (oclass->get_state)
1728 result = (oclass->get_state) (element, state, pending, timeout);
1734 * gst_element_abort_state:
1735 * @element: a #GstElement to abort the state of.
1737 * Abort the state change of the element. This function is used
1738 * by elements that do asynchronous state changes and find out
1739 * something is wrong.
1741 * This function should be called with the STATE_LOCK held.
1746 gst_element_abort_state (GstElement * element)
1750 g_return_if_fail (GST_IS_ELEMENT (element));
1752 pending = GST_STATE_PENDING (element);
1754 if (pending != GST_STATE_VOID_PENDING &&
1755 GST_STATE_RETURN (element) != GST_STATE_CHANGE_FAILURE) {
1756 #ifndef GST_DISABLE_GST_DEBUG
1757 GstState old_state = GST_STATE (element);
1759 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1760 "aborting state from %s to %s", gst_element_state_get_name (old_state),
1761 gst_element_state_get_name (pending));
1764 GST_STATE_RETURN (element) = GST_STATE_CHANGE_FAILURE;
1766 GST_STATE_BROADCAST (element);
1771 * gst_element_commit_state:
1772 * @element: a #GstElement to commit the state of.
1774 * Commit the state change of the element. This function is used
1775 * by elements that do asynchronous state changes.
1776 * The core will normally call this method automatically when an
1777 * element returned SUCCESS from the state change function.
1778 * Elements that return ASYNC from the change_state function should
1779 * eventually call this method from the streaming thread to signal
1780 * successfull state change completion.
1782 * If after calling this method the element still has not reached
1783 * the pending state, the next state change is performed.
1785 * This function can only be called with the STATE_LOCK held.
1787 * Returns: The result of the commit state change.
1791 GstStateChangeReturn
1792 gst_element_commit_state (GstElement * element)
1795 GstStateChangeReturn ret;
1797 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
1799 ret = GST_STATE_CHANGE_SUCCESS;
1801 pending = GST_STATE_PENDING (element);
1803 /* check if there is something to commit */
1804 if (pending != GST_STATE_VOID_PENDING) {
1806 GstState current, next;
1807 GstMessage *message;
1810 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_CHANGING_STATE);
1811 GST_UNLOCK (element);
1813 old_state = GST_STATE (element);
1814 /* this is the state we should go to next */
1815 next = GST_STATE_NEXT (element);
1816 /* update current state */
1817 current = GST_STATE (element) = next;
1819 /* see if we reached the final state */
1820 if (pending == next) {
1821 pending = GST_STATE_VOID_PENDING;
1822 GST_STATE_PENDING (element) = pending;
1823 GST_STATE_NEXT (element) = pending;
1824 ret = GST_STATE_CHANGE_SUCCESS;
1826 /* not there yet, will get there ASYNC */
1827 ret = GST_STATE_CHANGE_ASYNC;
1830 GST_STATE_RETURN (element) = ret;
1832 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1833 "committing state from %s to %s, pending %s",
1834 gst_element_state_get_name (old_state),
1835 gst_element_state_get_name (next),
1836 gst_element_state_get_name (pending));
1838 message = gst_message_new_state_changed (GST_OBJECT (element),
1839 FALSE, old_state, next, pending);
1840 gst_element_post_message (element, message);
1842 if (pending != GST_STATE_VOID_PENDING) {
1843 GstStateChange transition;
1845 /* calc new next state */
1846 next = GST_STATE_GET_NEXT (current, pending);
1848 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1849 "continue state change %s to %s, final %s",
1850 gst_element_state_get_name (current),
1851 gst_element_state_get_name (next),
1852 gst_element_state_get_name (pending));
1854 /* create transition */
1855 transition = GST_STATE_TRANSITION (current, next);
1857 /* perform next transition */
1858 ret = gst_element_change_state (element, transition);
1860 GST_STATE_BROADCAST (element);
1863 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_CHANGING_STATE);
1864 GST_UNLOCK (element);
1870 * gst_element_lost_state:
1871 * @element: a #GstElement the state is lost of
1873 * Brings the element to the lost state. The current state of the
1874 * element is copied to the pending state so that any call to
1875 * #gst_element_get_state() will return ASYNC.
1877 * This is mostly used for elements that lost their preroll buffer
1878 * in the PAUSED state after a flush, they become PAUSED again
1879 * if a new preroll buffer is queued.
1880 * This function can only be called when the element is currently
1881 * not in error or an async state change.
1883 * This function can only be called with the STATE_LOCK held.
1888 gst_element_lost_state (GstElement * element)
1890 g_return_if_fail (GST_IS_ELEMENT (element));
1892 if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING &&
1893 GST_STATE_RETURN (element) != GST_STATE_CHANGE_FAILURE) {
1894 GstState current_state;
1895 GstMessage *message;
1897 current_state = GST_STATE (element);
1899 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1900 "lost state of %s", gst_element_state_get_name (current_state));
1902 GST_STATE_NEXT (element) = current_state;
1903 GST_STATE_PENDING (element) = current_state;
1904 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
1906 message = gst_message_new_state_changed (GST_OBJECT (element),
1907 FALSE, current_state, current_state, current_state);
1908 gst_element_post_message (element, message);
1913 * gst_element_set_state:
1914 * @element: a #GstElement to change state of.
1915 * @state: the element's new #GstState.
1917 * Sets the state of the element. This function will try to set the
1918 * requested state by going through all the intermediary states and calling
1919 * the class's state change function for each.
1921 * This function can return GST_STATE_CHANGE_ASYNC, in which case the
1922 * element will perform the remainder of the state change asynchronously.
1923 * An application can use gst_element_get_state() to wait for the completion
1924 * of the state change or it can wait for a state change message on the bus.
1926 * Returns: Result of the state change using #GstStateChangeReturn.
1930 GstStateChangeReturn
1931 gst_element_set_state (GstElement * element, GstState state)
1933 GstState current, next, old_pending;
1934 GstStateChangeReturn ret;
1935 GstStateChange transition;
1936 GstStateChangeReturn old_ret;
1938 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
1940 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element, "set_state to %s",
1941 gst_element_state_get_name (state));
1943 GST_STATE_LOCK (element);
1946 GST_OBJECT_FLAG_SET (element, GST_ELEMENT_CHANGING_STATE);
1947 GST_UNLOCK (element);
1949 old_ret = GST_STATE_RETURN (element);
1950 /* previous state change returned an error, remove all pending
1951 * and next states */
1952 if (old_ret == GST_STATE_CHANGE_FAILURE) {
1953 GST_STATE_NEXT (element) = GST_STATE_VOID_PENDING;
1954 GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
1955 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
1958 current = GST_STATE (element);
1959 next = GST_STATE_NEXT (element);
1960 old_pending = GST_STATE_PENDING (element);
1962 /* this is the (new) state we should go to */
1963 GST_STATE_PENDING (element) = state;
1965 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1966 "current %s, old_pending %s, next %s, old return %d",
1967 gst_element_state_get_name (current),
1968 gst_element_state_get_name (old_pending),
1969 gst_element_state_get_name (next), old_ret);
1971 /* if the element was busy doing a state change, we just update the
1972 * target state, it'll get to it async then. */
1973 if (old_pending != GST_STATE_VOID_PENDING) {
1974 /* upwards state change will happen ASYNC */
1975 if (old_pending <= state)
1977 /* element is going to this state already */
1978 else if (next == state)
1980 /* element was performing an ASYNC upward state change and
1981 * we request to go downward again. Start from the next pending
1983 else if (next > state
1984 && GST_STATE_RETURN (element) == GST_STATE_CHANGE_ASYNC) {
1988 next = GST_STATE_GET_NEXT (current, state);
1990 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1991 "%s: setting state from %s to %s",
1992 (next != state ? "intermediate" : "final"),
1993 gst_element_state_get_name (current), gst_element_state_get_name (next));
1995 transition = GST_STATE_TRANSITION (current, next);
1997 ret = gst_element_change_state (element, transition);
2000 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_CHANGING_STATE);
2001 GST_UNLOCK (element);
2002 GST_STATE_UNLOCK (element);
2004 GST_DEBUG_OBJECT (element, "returned %d", ret);
2010 GST_STATE_RETURN (element) = GST_STATE_CHANGE_ASYNC;
2012 GST_OBJECT_FLAG_UNSET (element, GST_ELEMENT_CHANGING_STATE);
2013 GST_UNLOCK (element);
2014 GST_STATE_UNLOCK (element);
2016 GST_DEBUG_OBJECT (element, "element was busy with async state change");
2018 return GST_STATE_CHANGE_ASYNC;
2023 /* with STATE_LOCK */
2024 static GstStateChangeReturn
2025 gst_element_change_state (GstElement * element, GstStateChange transition)
2027 GstElementClass *oclass;
2028 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
2032 oclass = GST_ELEMENT_GET_CLASS (element);
2034 /* start with the current state. */
2035 current = GST_STATE_TRANSITION_CURRENT (transition);
2036 next = GST_STATE_TRANSITION_NEXT (transition);
2038 /* now we store the next state */
2039 GST_STATE_NEXT (element) = next;
2041 /* call the state change function so it can set the state */
2042 if (oclass->change_state)
2043 ret = (oclass->change_state) (element, transition);
2045 ret = GST_STATE_CHANGE_FAILURE;
2048 case GST_STATE_CHANGE_FAILURE:
2049 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2050 "have FAILURE change_state return");
2051 /* state change failure */
2052 gst_element_abort_state (element);
2054 case GST_STATE_CHANGE_ASYNC:
2055 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2056 "element will change state ASYNC");
2058 /* if we go upwards, we give the app a change to wait for
2063 /* else we just continue the state change downwards */
2064 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
2065 "forcing commit state %s < %s",
2066 gst_element_state_get_name (current),
2067 gst_element_state_get_name (next));
2069 GST_STATE_RETURN (element) = GST_STATE_CHANGE_SUCCESS;
2071 ret = gst_element_commit_state (element);
2073 case GST_STATE_CHANGE_SUCCESS:
2074 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2075 "element changed state SUCCESS");
2076 /* we can commit the state now which will proceeed to
2078 ret = gst_element_commit_state (element);
2080 case GST_STATE_CHANGE_NO_PREROLL:
2081 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2082 "element changed state NO_PREROLL");
2083 /* we can commit the state now which will proceeed to
2085 gst_element_commit_state (element);
2086 ret = GST_STATE_CHANGE_NO_PREROLL;
2089 ret = GST_STATE_CHANGE_FAILURE;
2090 goto invalid_return;
2094 GST_STATE_RETURN (element) = ret;
2096 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element, "exit state change %d", ret);
2103 GST_STATE_RETURN (element) = ret;
2104 /* somebody added a GST_STATE_ and forgot to do stuff here ! */
2105 g_critical ("unknown return value %d from a state change function", ret);
2110 /* gst_iterator_fold functions for pads_activate */
2113 activate_pads (GstPad * pad, GValue * ret, gboolean * active)
2115 if (!gst_pad_set_active (pad, *active))
2116 g_value_set_boolean (ret, FALSE);
2118 gst_pad_set_caps (pad, NULL);
2120 gst_object_unref (pad);
2124 /* returns false on error or early cutout of the fold, true otherwise */
2126 iterator_fold_with_resync (GstIterator * iter, GstIteratorFoldFunction func,
2127 GValue * ret, gpointer user_data)
2129 GstIteratorResult ires;
2130 gboolean res = TRUE;
2133 ires = gst_iterator_fold (iter, func, ret, user_data);
2136 case GST_ITERATOR_RESYNC:
2137 gst_iterator_resync (iter);
2139 case GST_ITERATOR_DONE:
2152 /* is called with STATE_LOCK
2155 gst_element_pads_activate (GstElement * element, gboolean active)
2157 GValue ret = { 0, };
2161 GST_DEBUG_OBJECT (element, "pads_activate with active %d", active);
2162 /* no need to unset this later, it's just a boolean */
2163 g_value_init (&ret, G_TYPE_BOOLEAN);
2164 g_value_set_boolean (&ret, TRUE);
2166 iter = gst_element_iterate_src_pads (element);
2167 fold_ok = iterator_fold_with_resync
2168 (iter, (GstIteratorFoldFunction) activate_pads, &ret, &active);
2169 gst_iterator_free (iter);
2170 if (!fold_ok || !g_value_get_boolean (&ret)) {
2171 GST_DEBUG_OBJECT (element, "pads_activate failed");
2175 iter = gst_element_iterate_sink_pads (element);
2176 fold_ok = iterator_fold_with_resync
2177 (iter, (GstIteratorFoldFunction) activate_pads, &ret, &active);
2178 gst_iterator_free (iter);
2179 if (!fold_ok || !g_value_get_boolean (&ret)) {
2180 GST_DEBUG_OBJECT (element, "pads_activate failed");
2184 GST_DEBUG_OBJECT (element, "pads_activate successful");
2188 /* is called with STATE_LOCK */
2189 static GstStateChangeReturn
2190 gst_element_change_state_func (GstElement * element, GstStateChange transition)
2192 GstState state, next;
2193 GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;
2195 g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_CHANGE_FAILURE);
2197 state = GST_STATE_TRANSITION_CURRENT (transition);
2198 next = GST_STATE_TRANSITION_NEXT (transition);
2200 /* if the element already is in the given state, we just return success */
2201 if (next == GST_STATE_VOID_PENDING || state == next)
2204 GST_CAT_LOG_OBJECT (GST_CAT_STATES, element,
2205 "default handler tries setting state from %s to %s (%04x)",
2206 gst_element_state_get_name (state),
2207 gst_element_state_get_name (next), transition);
2209 switch (transition) {
2210 case GST_STATE_CHANGE_NULL_TO_READY:
2212 case GST_STATE_CHANGE_READY_TO_PAUSED:
2213 if (!gst_element_pads_activate (element, TRUE)) {
2214 result = GST_STATE_CHANGE_FAILURE;
2217 case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
2219 case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
2221 case GST_STATE_CHANGE_PAUSED_TO_READY:
2222 case GST_STATE_CHANGE_READY_TO_NULL:
2223 /* deactivate pads in both cases, since they are activated on
2224 ready->paused but the element might not have made it to paused */
2225 if (!gst_element_pads_activate (element, FALSE)) {
2226 result = GST_STATE_CHANGE_FAILURE;
2228 gst_element_set_base_time (element, 0);
2232 /* this will catch real but unhandled state changes;
2233 * can only be caused by:
2234 * - a new state was added
2235 * - somehow the element was asked to jump across an intermediate state
2237 g_warning ("Unhandled state change from %s to %s",
2238 gst_element_state_get_name (state),
2239 gst_element_state_get_name (next));
2246 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
2247 "element is already in the %s state",
2248 gst_element_state_get_name (state));
2249 return GST_STATE_RETURN (element);
2254 * gst_element_get_factory:
2255 * @element: a #GstElement to request the element factory of.
2257 * Retrieves the factory that was used to create this element.
2259 * Returns: the #GstElementFactory used for creating this element.
2260 * no refcounting is needed.
2263 gst_element_get_factory (GstElement * element)
2265 g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
2267 return GST_ELEMENT_GET_CLASS (element)->elementfactory;
2271 gst_element_dispose (GObject * object)
2273 GstElement *element = GST_ELEMENT (object);
2275 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "dispose");
2277 if (GST_STATE (element) != GST_STATE_NULL) {
2279 ("\nTrying to dispose element %s, but it is not in the NULL state.\n"
2280 "You need to explicitly set elements to the NULL state before\n"
2281 "dropping the final reference, to allow them to clean up.\n",
2282 GST_OBJECT_NAME (element));
2285 g_return_if_fail (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING);
2287 /* first we break all our links with the outside */
2288 while (element->pads) {
2289 gst_element_remove_pad (element, GST_PAD_CAST (element->pads->data));
2291 if (G_UNLIKELY (element->pads != 0)) {
2292 g_critical ("could not remove pads from element %s",
2293 GST_STR_NULL (GST_OBJECT_NAME (object)));
2297 gst_object_replace ((GstObject **) & element->clock, NULL);
2298 gst_object_replace ((GstObject **) & element->bus, NULL);
2299 GST_UNLOCK (element);
2301 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "parent class dispose");
2303 G_OBJECT_CLASS (parent_class)->dispose (object);
2307 gst_element_finalize (GObject * object)
2309 GstElement *element = GST_ELEMENT (object);
2311 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize");
2313 GST_STATE_LOCK (element);
2314 if (element->state_cond)
2315 g_cond_free (element->state_cond);
2316 element->state_cond = NULL;
2317 GST_STATE_UNLOCK (element);
2318 g_static_rec_mutex_free (element->state_lock);
2319 g_free (element->state_lock);
2320 element->state_lock = NULL;
2322 GST_CAT_INFO_OBJECT (GST_CAT_REFCOUNTING, element, "finalize parent");
2324 G_OBJECT_CLASS (parent_class)->finalize (object);
2327 #ifndef GST_DISABLE_LOADSAVE
2329 * gst_element_save_thyself:
2330 * @element: a #GstElement to save.
2331 * @parent: the xml parent node.
2333 * Saves the element as part of the given XML structure.
2335 * Returns: the new #xmlNodePtr.
2338 gst_element_save_thyself (GstObject * object, xmlNodePtr parent)
2341 GstElementClass *oclass;
2342 GParamSpec **specs, *spec;
2345 GValue value = { 0, };
2346 GstElement *element;
2348 g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
2350 element = GST_ELEMENT (object);
2352 oclass = GST_ELEMENT_GET_CLASS (element);
2354 xmlNewChild (parent, NULL, (xmlChar *) "name",
2355 (xmlChar *) GST_ELEMENT_NAME (element));
2357 if (oclass->elementfactory != NULL) {
2358 GstElementFactory *factory = (GstElementFactory *) oclass->elementfactory;
2360 xmlNewChild (parent, NULL, (xmlChar *) "type",
2361 (xmlChar *) GST_PLUGIN_FEATURE (factory)->name);
2365 specs = g_object_class_list_properties (G_OBJECT_GET_CLASS (object), &nspecs);
2367 for (i = 0; i < nspecs; i++) {
2369 if (spec->flags & G_PARAM_READABLE) {
2373 g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (spec));
2375 g_object_get_property (G_OBJECT (element), spec->name, &value);
2376 param = xmlNewChild (parent, NULL, (xmlChar *) "param", NULL);
2377 xmlNewChild (param, NULL, (xmlChar *) "name", (xmlChar *) spec->name);
2379 if (G_IS_PARAM_SPEC_STRING (spec))
2380 contents = g_value_dup_string (&value);
2381 else if (G_IS_PARAM_SPEC_ENUM (spec))
2382 contents = g_strdup_printf ("%d", g_value_get_enum (&value));
2383 else if (G_IS_PARAM_SPEC_INT64 (spec))
2384 contents = g_strdup_printf ("%" G_GINT64_FORMAT,
2385 g_value_get_int64 (&value));
2387 contents = g_strdup_value_contents (&value);
2389 xmlNewChild (param, NULL, (xmlChar *) "value", (xmlChar *) contents);
2392 g_value_unset (&value);
2398 pads = GST_ELEMENT_PADS (element);
2401 GstPad *pad = GST_PAD (pads->data);
2403 /* figure out if it's a direct pad or a ghostpad */
2404 if (GST_ELEMENT (GST_OBJECT_PARENT (pad)) == element) {
2405 xmlNodePtr padtag = xmlNewChild (parent, NULL, (xmlChar *) "pad", NULL);
2407 gst_object_save_thyself (GST_OBJECT (pad), padtag);
2409 pads = g_list_next (pads);
2416 gst_element_restore_thyself (GstObject * object, xmlNodePtr self)
2418 xmlNodePtr children;
2419 GstElement *element;
2421 gchar *value = NULL;
2423 element = GST_ELEMENT (object);
2424 g_return_if_fail (element != NULL);
2427 children = self->xmlChildrenNode;
2429 if (!strcmp ((char *) children->name, "param")) {
2430 xmlNodePtr child = children->xmlChildrenNode;
2433 if (!strcmp ((char *) child->name, "name")) {
2434 name = (gchar *) xmlNodeGetContent (child);
2435 } else if (!strcmp ((char *) child->name, "value")) {
2436 value = (gchar *) xmlNodeGetContent (child);
2438 child = child->next;
2440 /* FIXME: can this just be g_object_set ? */
2441 gst_util_set_object_arg (G_OBJECT (element), name, value);
2442 /* g_object_set (G_OBJECT (element), name, value, NULL); */
2446 children = children->next;
2450 children = self->xmlChildrenNode;
2452 if (!strcmp ((char *) children->name, "pad")) {
2453 gst_pad_load_and_link (children, GST_OBJECT (element));
2455 children = children->next;
2458 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
2459 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
2461 #endif /* GST_DISABLE_LOADSAVE */
2464 gst_element_set_bus_func (GstElement * element, GstBus * bus)
2466 g_return_if_fail (GST_IS_ELEMENT (element));
2468 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, element, "setting bus to %p", bus);
2471 gst_object_replace ((GstObject **) & GST_ELEMENT_BUS (element),
2472 GST_OBJECT_CAST (bus));
2473 GST_UNLOCK (element);
2477 * gst_element_set_bus:
2478 * @element: a #GstElement to set the bus of.
2479 * @bus: the #GstBus to set.
2481 * Sets the bus of the element. For internal use only, unless you're
2487 gst_element_set_bus (GstElement * element, GstBus * bus)
2489 GstElementClass *oclass;
2491 g_return_if_fail (GST_IS_ELEMENT (element));
2493 oclass = GST_ELEMENT_GET_CLASS (element);
2495 if (oclass->set_bus)
2496 oclass->set_bus (element, bus);
2500 * gst_element_get_bus:
2501 * @element: a #GstElement to get the bus of.
2503 * Returns the bus of the element.
2505 * Returns: the element's #GstBus. unref after usage.
2510 gst_element_get_bus (GstElement * element)
2512 GstBus *result = NULL;
2514 g_return_val_if_fail (GST_IS_ELEMENT (element), result);
2517 result = GST_ELEMENT_BUS (element);
2518 gst_object_ref (result);
2519 GST_UNLOCK (element);
2521 GST_DEBUG_OBJECT (element, "got bus %" GST_PTR_FORMAT, result);