c57d5eca8427d82472040bc1ddf3a62f6fe6fa8b
1 /* GStreamer
2 *
3 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
4 * 2004 Wim Taymans <wim@fluendo.com>
5 *
6 * gstbin.c: GstBin container object and support code
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
17 *
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
22 *
23 * MT safe.
24 */
25 /**
26 * SECTION:gstbin
27 * @short_description: Base class for elements that contain other elements
28 *
29 * GstBin is the simplest of the container elements, allowing elements to
30 * become children of itself. Pads from the child elements can be ghosted to
31 * the bin, making the bin itself look transparently like any other element,
32 * allowing for deep nesting of predefined sub-pipelines.
33 *
34 * A new GstBin is created with gst_bin_new(). Use a #GstPipeline instead if you
35 * want to create a toplevel bin because a normal bin doesn't have a bus or
36 * handle clock distribution of its own.
37 *
38 * After the bin has been created you will typically add elements to it with
39 * gst_bin_add(). You can remove elements with gst_bin_remove().
40 *
41 * An element can be retrieved from a bin with gst_bin_get_by_name(), using the
42 * elements name. gst_bin_get_by_name_recurse_up() is mainly used for internal
43 * purposes and will query the parent bins when the element is not found in the
44 * current bin.
45 *
46 * An iterator of elements in a bin can be retrieved with
47 * gst_bin_iterate_elements(). Various other iterators exist to retrieve the
48 * elements in a bin.
49 *
50 * The "element_added" signal is fired whenever a new element is added to the
51 * bin. Likewise the "element_removed" signal is fired whenever an element is
52 * removed from the bin.
53 *
54 * gst_bin_unref() is used to destroy the bin.
55 */
57 #include "gst_private.h"
59 #include "gstevent.h"
60 #include "gstbin.h"
61 #include "gstmarshal.h"
62 #include "gstxml.h"
63 #include "gstinfo.h"
64 #include "gsterror.h"
66 #include "gstindex.h"
67 #include "gstindexfactory.h"
68 #include "gstutils.h"
69 #include "gstchildproxy.h"
71 GST_DEBUG_CATEGORY_STATIC (bin_debug);
72 #define GST_CAT_DEFAULT bin_debug
73 #define GST_LOG_BIN_CONTENTS(bin, text) GST_LOG_OBJECT ((bin), \
74 text ": %d elements: %u PLAYING, %u PAUSED, %u READY, %u NULL, own state: %s", \
75 (bin)->numchildren, (guint) (bin)->child_states[3], \
76 (guint) (bin)->child_states[2], (bin)->child_states[1], \
77 (bin)->child_states[0], gst_element_state_get_name (GST_STATE (bin)))
80 static GstElementDetails gst_bin_details = GST_ELEMENT_DETAILS ("Generic bin",
81 "Generic/Bin",
82 "Simple container object",
83 "Erik Walthinsen <omega@cse.ogi.edu>," "Wim Taymans <wim@fluendo.com>");
85 GType _gst_bin_type = 0;
87 static void gst_bin_dispose (GObject * object);
89 static GstStateChangeReturn gst_bin_change_state (GstElement * element,
90 GstStateChange transition);
91 static GstStateChangeReturn gst_bin_get_state (GstElement * element,
92 GstState * state, GstState * pending, GTimeVal * timeout);
94 static gboolean gst_bin_add_func (GstBin * bin, GstElement * element);
95 static gboolean gst_bin_remove_func (GstBin * bin, GstElement * element);
97 #ifndef GST_DISABLE_INDEX
98 static void gst_bin_set_index_func (GstElement * element, GstIndex * index);
99 #endif
100 static GstClock *gst_bin_get_clock_func (GstElement * element);
101 static void gst_bin_set_clock_func (GstElement * element, GstClock * clock);
103 static gboolean gst_bin_send_event (GstElement * element, GstEvent * event);
104 static GstBusSyncReply bin_bus_handler (GstBus * bus,
105 GstMessage * message, GstBin * bin);
106 static gboolean gst_bin_query (GstElement * element, GstQuery * query);
108 #ifndef GST_DISABLE_LOADSAVE
109 static xmlNodePtr gst_bin_save_thyself (GstObject * object, xmlNodePtr parent);
110 static void gst_bin_restore_thyself (GstObject * object, xmlNodePtr self);
111 #endif
113 static gint bin_element_is_sink (GstElement * child, GstBin * bin);
115 /* Bin signals and args */
116 enum
117 {
118 ELEMENT_ADDED,
119 ELEMENT_REMOVED,
120 LAST_SIGNAL
121 };
123 enum
124 {
125 ARG_0
126 /* FILL ME */
127 };
129 static void gst_bin_base_init (gpointer g_class);
130 static void gst_bin_class_init (GstBinClass * klass);
131 static void gst_bin_init (GstBin * bin);
132 static void gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data);
134 static GstElementClass *parent_class = NULL;
135 static guint gst_bin_signals[LAST_SIGNAL] = { 0 };
137 /**
138 * gst_bin_get_type:
139 *
140 * Returns: the type of #GstBin
141 */
142 GType
143 gst_bin_get_type (void)
144 {
145 if (!_gst_bin_type) {
146 static const GTypeInfo bin_info = {
147 sizeof (GstBinClass),
148 gst_bin_base_init,
149 NULL,
150 (GClassInitFunc) gst_bin_class_init,
151 NULL,
152 NULL,
153 sizeof (GstBin),
154 0,
155 (GInstanceInitFunc) gst_bin_init,
156 NULL
157 };
158 static const GInterfaceInfo child_proxy_info = {
159 gst_bin_child_proxy_init,
160 NULL,
161 NULL
162 };
164 _gst_bin_type =
165 g_type_register_static (GST_TYPE_ELEMENT, "GstBin", &bin_info, 0);
167 g_type_add_interface_static (_gst_bin_type, GST_TYPE_CHILD_PROXY,
168 &child_proxy_info);
170 GST_DEBUG_CATEGORY_INIT (bin_debug, "bin", GST_DEBUG_BOLD,
171 "debugging info for the 'bin' container element");
172 }
173 return _gst_bin_type;
174 }
176 static void
177 gst_bin_base_init (gpointer g_class)
178 {
179 GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
181 gst_element_class_set_details (gstelement_class, &gst_bin_details);
182 }
184 static GstObject *
185 gst_bin_child_proxy_get_child_by_index (GstChildProxy * child_proxy,
186 guint index)
187 {
188 return g_list_nth_data (GST_BIN (child_proxy)->children, index);
189 }
191 guint
192 gst_bin_child_proxy_get_children_count (GstChildProxy * child_proxy)
193 {
194 return GST_BIN (child_proxy)->numchildren;
195 }
197 static void
198 gst_bin_child_proxy_init (gpointer g_iface, gpointer iface_data)
199 {
200 GstChildProxyInterface *iface = g_iface;
202 iface->get_children_count = gst_bin_child_proxy_get_children_count;
203 iface->get_child_by_index = gst_bin_child_proxy_get_child_by_index;
204 }
206 static void
207 gst_bin_class_init (GstBinClass * klass)
208 {
209 GObjectClass *gobject_class;
210 GstObjectClass *gstobject_class;
211 GstElementClass *gstelement_class;
213 gobject_class = (GObjectClass *) klass;
214 gstobject_class = (GstObjectClass *) klass;
215 gstelement_class = (GstElementClass *) klass;
217 parent_class = g_type_class_peek_parent (klass);
219 /**
220 * GstBin::element-added:
221 * @bin: the object which emitted the signal.
222 * @element: the element that was added to the bin
223 *
224 * Will be emitted if a new element was removed/added to this bin.
225 */
226 gst_bin_signals[ELEMENT_ADDED] =
227 g_signal_new ("element-added", G_TYPE_FROM_CLASS (klass),
228 G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_added), NULL,
229 NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
230 /**
231 * GstBin::element-removed:
232 * @bin: the object which emitted the signal.
233 * @element: the element that was removed from the bin
234 *
235 * Will be emitted if an element was removed from this bin.
236 */
237 gst_bin_signals[ELEMENT_REMOVED] =
238 g_signal_new ("element-removed", G_TYPE_FROM_CLASS (klass),
239 G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstBinClass, element_removed), NULL,
240 NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_ELEMENT);
242 gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_bin_dispose);
244 #ifndef GST_DISABLE_LOADSAVE
245 gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_bin_save_thyself);
246 gstobject_class->restore_thyself =
247 GST_DEBUG_FUNCPTR (gst_bin_restore_thyself);
248 #endif
250 gstelement_class->change_state = GST_DEBUG_FUNCPTR (gst_bin_change_state);
251 gstelement_class->get_state = GST_DEBUG_FUNCPTR (gst_bin_get_state);
252 #ifndef GST_DISABLE_INDEX
253 gstelement_class->set_index = GST_DEBUG_FUNCPTR (gst_bin_set_index_func);
254 #endif
255 gstelement_class->get_clock = GST_DEBUG_FUNCPTR (gst_bin_get_clock_func);
256 gstelement_class->set_clock = GST_DEBUG_FUNCPTR (gst_bin_set_clock_func);
258 gstelement_class->send_event = GST_DEBUG_FUNCPTR (gst_bin_send_event);
259 gstelement_class->query = GST_DEBUG_FUNCPTR (gst_bin_query);
261 klass->add_element = GST_DEBUG_FUNCPTR (gst_bin_add_func);
262 klass->remove_element = GST_DEBUG_FUNCPTR (gst_bin_remove_func);
263 }
265 static void
266 gst_bin_init (GstBin * bin)
267 {
268 GstBus *bus;
270 bin->numchildren = 0;
271 bin->children = NULL;
272 bin->children_cookie = 0;
273 bin->eosed = NULL;
275 /* Set up a bus for listening to child elements,
276 * and one for sending messages up the hierarchy */
277 bus = g_object_new (gst_bus_get_type (), NULL);
278 bin->child_bus = bus;
279 gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bin_bus_handler, bin);
281 bus = g_object_new (gst_bus_get_type (), NULL);
282 gst_element_set_bus (GST_ELEMENT (bin), bus);
283 /* set_bus refs the bus via gst_object_replace, we drop our ref */
284 gst_object_unref (bus);
285 }
287 /**
288 * gst_bin_new:
289 * @name: name of new bin
290 *
291 * Create a new bin with given name.
292 *
293 * Returns: new bin
294 */
295 GstElement *
296 gst_bin_new (const gchar * name)
297 {
298 return gst_element_factory_make ("bin", name);
299 }
301 /* set the index on all elements in this bin
302 *
303 * MT safe
304 */
305 #ifndef GST_DISABLE_INDEX
306 static void
307 gst_bin_set_index_func (GstElement * element, GstIndex * index)
308 {
309 GstBin *bin;
310 GList *children;
312 bin = GST_BIN (element);
314 GST_LOCK (bin);
315 for (children = bin->children; children; children = g_list_next (children)) {
316 GstElement *child = GST_ELEMENT (children->data);
318 gst_element_set_index (child, index);
319 }
320 GST_UNLOCK (bin);
321 }
322 #endif
324 /* set the clock on all elements in this bin
325 *
326 * MT safe
327 */
328 static void
329 gst_bin_set_clock_func (GstElement * element, GstClock * clock)
330 {
331 GList *children;
332 GstBin *bin;
334 bin = GST_BIN (element);
336 GST_LOCK (bin);
337 for (children = bin->children; children; children = g_list_next (children)) {
338 GstElement *child = GST_ELEMENT (children->data);
340 gst_element_set_clock (child, clock);
341 }
342 GST_UNLOCK (bin);
343 }
345 /* get the clock for this bin by asking all of the children in this bin
346 *
347 * MT safe
348 */
349 static GstClock *
350 gst_bin_get_clock_func (GstElement * element)
351 {
352 GstClock *result = NULL;
353 GstBin *bin;
354 GList *children;
356 bin = GST_BIN (element);
358 GST_LOCK (bin);
359 for (children = bin->children; children; children = g_list_next (children)) {
360 GstElement *child = GST_ELEMENT (children->data);
362 result = gst_element_get_clock (child);
363 if (result)
364 break;
365 }
366 GST_UNLOCK (bin);
368 return result;
369 }
371 static gboolean
372 is_eos (GstBin * bin)
373 {
374 GstIterator *sinks;
375 gboolean result = TRUE;
376 gboolean done = FALSE;
378 sinks = gst_bin_iterate_sinks (bin);
379 while (!done) {
380 gpointer data;
382 switch (gst_iterator_next (sinks, &data)) {
383 case GST_ITERATOR_OK:
384 {
385 GstElement *element = GST_ELEMENT (data);
386 GList *eosed;
387 gchar *name;
389 name = gst_element_get_name (element);
390 eosed = g_list_find (bin->eosed, element);
391 if (!eosed) {
392 GST_DEBUG ("element %s did not post EOS yet", name);
393 result = FALSE;
394 done = TRUE;
395 } else {
396 GST_DEBUG ("element %s posted EOS", name);
397 }
398 g_free (name);
399 gst_object_unref (element);
400 break;
401 }
402 case GST_ITERATOR_RESYNC:
403 result = TRUE;
404 gst_iterator_resync (sinks);
405 break;
406 case GST_ITERATOR_DONE:
407 done = TRUE;
408 break;
409 default:
410 g_assert_not_reached ();
411 break;
412 }
413 }
414 gst_iterator_free (sinks);
415 return result;
416 }
418 static void
419 unlink_pads (GstPad * pad)
420 {
421 GstPad *peer;
423 if ((peer = gst_pad_get_peer (pad))) {
424 if (gst_pad_get_direction (pad) == GST_PAD_SRC)
425 gst_pad_unlink (pad, peer);
426 else
427 gst_pad_unlink (peer, pad);
428 gst_object_unref (peer);
429 }
430 gst_object_unref (pad);
431 }
433 /* add an element to this bin
434 *
435 * MT safe
436 */
437 static gboolean
438 gst_bin_add_func (GstBin * bin, GstElement * element)
439 {
440 gchar *elem_name;
441 GstIterator *it;
443 /* we obviously can't add ourself to ourself */
444 if (G_UNLIKELY (GST_ELEMENT_CAST (element) == GST_ELEMENT_CAST (bin)))
445 goto adding_itself;
447 /* get the element name to make sure it is unique in this bin. */
448 GST_LOCK (element);
449 elem_name = g_strdup (GST_ELEMENT_NAME (element));
450 GST_UNLOCK (element);
452 GST_LOCK (bin);
454 /* then check to see if the element's name is already taken in the bin,
455 * we can safely take the lock here. This check is probably bogus because
456 * you can safely change the element name after this check and before setting
457 * the object parent. The window is very small though... */
458 if (G_UNLIKELY (!gst_object_check_uniqueness (bin->children, elem_name)))
459 goto duplicate_name;
461 /* set the element's parent and add the element to the bin's list of children */
462 if (G_UNLIKELY (!gst_object_set_parent (GST_OBJECT_CAST (element),
463 GST_OBJECT_CAST (bin))))
464 goto had_parent;
466 /* if we add a sink we become a sink */
467 if (GST_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK)) {
468 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "element \"%s\" was sink",
469 elem_name);
470 GST_FLAG_SET (bin, GST_ELEMENT_IS_SINK);
471 }
473 bin->children = g_list_prepend (bin->children, element);
474 bin->numchildren++;
475 bin->children_cookie++;
477 /* distribute the bus */
478 gst_element_set_bus (element, bin->child_bus);
480 /* propagate the current base time and clock */
481 gst_element_set_base_time (element, GST_ELEMENT (bin)->base_time);
482 gst_element_set_clock (element, GST_ELEMENT_CLOCK (bin));
484 GST_UNLOCK (bin);
486 /* unlink all linked pads */
487 it = gst_element_iterate_pads (element);
488 gst_iterator_foreach (it, (GFunc) unlink_pads, element);
489 gst_iterator_free (it);
491 GST_CAT_DEBUG_OBJECT (GST_CAT_PARENTAGE, bin, "added element \"%s\"",
492 elem_name);
493 g_free (elem_name);
495 g_signal_emit (G_OBJECT (bin), gst_bin_signals[ELEMENT_ADDED], 0, element);
497 return TRUE;
499 /* ERROR handling here */
500 adding_itself:
501 {
502 GST_LOCK (bin);
503 g_warning ("Cannot add bin %s to itself", GST_ELEMENT_NAME (bin));
504 GST_UNLOCK (bin);
505 return FALSE;
506 }
507 duplicate_name:
508 {
509 g_warning ("Name %s is not unique in bin %s, not adding",
510 elem_name, GST_ELEMENT_NAME (bin));
511 GST_UNLOCK (bin);
512 g_free (elem_name);
513 return FALSE;
514 }
515 had_parent:
516 {
517 g_warning ("Element %s already has parent", elem_name);
518 GST_UNLOCK (bin);
519 g_free (elem_name);
520 return FALSE;
521 }
522 }
525 /**
526 * gst_bin_add:
527 * @bin: #GstBin to add element to
528 * @element: #GstElement to add to bin
529 *
530 * Adds the given element to the bin. Sets the element's parent, and thus
531 * takes ownership of the element. An element can only be added to one bin.
532 *
533 * If the element's pads are linked to other pads, the pads will be unlinked
534 * before the element is added to the bin.
535 *
536 * MT safe.
537 *
538 * Returns: TRUE if the element could be added, FALSE on wrong parameters or
539 * the bin does not want to accept the element.
540 */
541 gboolean
542 gst_bin_add (GstBin * bin, GstElement * element)
543 {
544 GstBinClass *bclass;
545 gboolean result;
547 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
548 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
550 bclass = GST_BIN_GET_CLASS (bin);
552 if (G_UNLIKELY (bclass->add_element == NULL))
553 goto no_function;
555 GST_CAT_DEBUG (GST_CAT_PARENTAGE, "adding element %s to bin %s",
556 GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
558 result = bclass->add_element (bin, element);
560 return result;
562 /* ERROR handling */
563 no_function:
564 {
565 g_warning ("adding elements to bin %s is not supported",
566 GST_ELEMENT_NAME (bin));
567 return FALSE;
568 }
569 }
571 /* remove an element from the bin
572 *
573 * MT safe
574 */
575 static gboolean
576 gst_bin_remove_func (GstBin * bin, GstElement * element)
577 {
578 gchar *elem_name;
579 GstIterator *it;
581 GST_LOCK (element);
582 /* Check if the element is already being removed and immediately
583 * return */
584 if (G_UNLIKELY (GST_FLAG_IS_SET (element, GST_ELEMENT_UNPARENTING)))
585 goto already_removing;
587 GST_FLAG_SET (element, GST_ELEMENT_UNPARENTING);
588 /* grab element name so we can print it */
589 elem_name = g_strdup (GST_ELEMENT_NAME (element));
590 GST_UNLOCK (element);
592 /* unlink all linked pads */
593 it = gst_element_iterate_pads (element);
594 gst_iterator_foreach (it, (GFunc) unlink_pads, element);
595 gst_iterator_free (it);
597 GST_LOCK (bin);
598 /* the element must be in the bin's list of children */
599 if (G_UNLIKELY (g_list_find (bin->children, element) == NULL))
600 goto not_in_bin;
602 /* now remove the element from the list of elements */
603 bin->children = g_list_remove (bin->children, element);
604 bin->numchildren--;
605 bin->children_cookie++;
607 /* check if we removed a sink */
608 if (GST_FLAG_IS_SET (element, GST_ELEMENT_IS_SINK)) {
609 GList *other_sink;
611 /* check if we removed the last sink */
612 other_sink = g_list_find_custom (bin->children,
613 bin, (GCompareFunc) bin_element_is_sink);
614 if (!other_sink) {
615 /* yups, we're not a sink anymore */
616 GST_FLAG_UNSET (bin, GST_ELEMENT_IS_SINK);
617 }
618 }
619 GST_UNLOCK (bin);
621 GST_CAT_INFO_OBJECT (GST_CAT_PARENTAGE, bin, "removed child \"%s\"",
622 elem_name);
623 g_free (elem_name);
625 gst_element_set_bus (element, NULL);
627 /* unlock any waiters for the state change. It is possible that
628 * we are waiting for an ASYNC state change on this element. The
629 * element cannot be added to another bin yet as it is not yet
630 * unparented. */
631 GST_STATE_LOCK (element);
632 GST_STATE_BROADCAST (element);
633 GST_STATE_UNLOCK (element);
635 /* we ref here because after the _unparent() the element can be disposed
636 * and we still need it to reset the UNPARENTING flag and fire a signal. */
637 gst_object_ref (element);
638 gst_object_unparent (GST_OBJECT_CAST (element));
640 GST_LOCK (element);
641 GST_FLAG_UNSET (element, GST_ELEMENT_UNPARENTING);
642 GST_UNLOCK (element);
644 g_signal_emit (G_OBJECT (bin), gst_bin_signals[ELEMENT_REMOVED], 0, element);
646 /* element is really out of our control now */
647 gst_object_unref (element);
649 return TRUE;
651 /* ERROR handling */
652 not_in_bin:
653 {
654 g_warning ("Element %s is not in bin %s", elem_name,
655 GST_ELEMENT_NAME (bin));
656 GST_UNLOCK (bin);
657 g_free (elem_name);
658 return FALSE;
659 }
660 already_removing:
661 {
662 GST_UNLOCK (element);
663 return FALSE;
664 }
665 }
667 /**
668 * gst_bin_remove:
669 * @bin: #GstBin to remove element from
670 * @element: #GstElement to remove
671 *
672 * Remove the element from its associated bin, unparenting it as well.
673 * Unparenting the element means that the element will be dereferenced,
674 * so if the bin holds the only reference to the element, the element
675 * will be freed in the process of removing it from the bin. If you
676 * want the element to still exist after removing, you need to call
677 * gst_object_ref() before removing it from the bin.
678 *
679 * If the element's pads are linked to other pads, the pads will be unlinked
680 * before the element is removed from the bin.
681 *
682 * MT safe.
683 *
684 * Returns: TRUE if the element could be removed, FALSE on wrong parameters or
685 * the bin does not want to remove the element.
686 */
687 gboolean
688 gst_bin_remove (GstBin * bin, GstElement * element)
689 {
690 GstBinClass *bclass;
691 gboolean result;
693 g_return_val_if_fail (GST_IS_BIN (bin), FALSE);
694 g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
696 bclass = GST_BIN_GET_CLASS (bin);
698 if (G_UNLIKELY (bclass->remove_element == NULL))
699 goto no_function;
701 GST_CAT_DEBUG (GST_CAT_PARENTAGE, "removing element %s from bin %s",
702 GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin));
704 result = bclass->remove_element (bin, element);
706 return result;
708 /* ERROR handling */
709 no_function:
710 {
711 g_warning ("removing elements from bin %s is not supported",
712 GST_ELEMENT_NAME (bin));
713 return FALSE;
714 }
715 }
717 static GstIteratorItem
718 iterate_child (GstIterator * it, GstElement * child)
719 {
720 gst_object_ref (child);
721 return GST_ITERATOR_ITEM_PASS;
722 }
724 /**
725 * gst_bin_iterate_elements:
726 * @bin: #Gstbin to iterate the elements of
727 *
728 * Get an iterator for the elements in this bin.
729 * Each element will have its refcount increased, so unref
730 * after use.
731 *
732 * MT safe.
733 *
734 * Returns: a #GstIterator of #GstElements. gst_iterator_free after
735 * use. returns NULL when passing bad parameters.
736 */
737 GstIterator *
738 gst_bin_iterate_elements (GstBin * bin)
739 {
740 GstIterator *result;
742 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
744 GST_LOCK (bin);
745 /* add ref because the iterator refs the bin. When the iterator
746 * is freed it will unref the bin again using the provided dispose
747 * function. */
748 gst_object_ref (bin);
749 result = gst_iterator_new_list (GST_GET_LOCK (bin),
750 &bin->children_cookie,
751 &bin->children,
752 bin,
753 (GstIteratorItemFunction) iterate_child,
754 (GstIteratorDisposeFunction) gst_object_unref);
755 GST_UNLOCK (bin);
757 return result;
758 }
760 static GstIteratorItem
761 iterate_child_recurse (GstIterator * it, GstElement * child)
762 {
763 gst_object_ref (child);
764 if (GST_IS_BIN (child)) {
765 GstIterator *other = gst_bin_iterate_recurse (GST_BIN (child));
767 gst_iterator_push (it, other);
768 }
769 return GST_ITERATOR_ITEM_PASS;
770 }
772 /**
773 * gst_bin_iterate_recurse:
774 * @bin: #Gstbin to iterate the elements of
775 *
776 * Get an iterator for the elements in this bin.
777 * Each element will have its refcount increased, so unref
778 * after use. This iterator recurses into GstBin children.
779 *
780 * MT safe.
781 *
782 * Returns: a #GstIterator of #GstElements. gst_iterator_free after
783 * use. returns NULL when passing bad parameters.
784 */
785 GstIterator *
786 gst_bin_iterate_recurse (GstBin * bin)
787 {
788 GstIterator *result;
790 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
792 GST_LOCK (bin);
793 /* add ref because the iterator refs the bin. When the iterator
794 * is freed it will unref the bin again using the provided dispose
795 * function. */
796 gst_object_ref (bin);
797 result = gst_iterator_new_list (GST_GET_LOCK (bin),
798 &bin->children_cookie,
799 &bin->children,
800 bin,
801 (GstIteratorItemFunction) iterate_child_recurse,
802 (GstIteratorDisposeFunction) gst_object_unref);
803 GST_UNLOCK (bin);
805 return result;
806 }
808 /* returns 0 when TRUE because this is a GCompareFunc */
809 /* MT safe */
810 static gint
811 bin_element_is_sink (GstElement * child, GstBin * bin)
812 {
813 gboolean is_sink;
815 /* we lock the child here for the remainder of the function to
816 * get its name safely. */
817 GST_LOCK (child);
818 is_sink = GST_FLAG_IS_SET (child, GST_ELEMENT_IS_SINK);
820 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
821 "child %s %s sink", GST_OBJECT_NAME (child), is_sink ? "is" : "is not");
823 GST_UNLOCK (child);
824 return is_sink ? 0 : 1;
825 }
827 /* returns 0 when TRUE because this is a GCompareFunc.
828 * This function returns elements that have no connected srcpads and
829 * are therefore not reachable from a real sink. */
830 /* MT safe */
831 static gint
832 bin_element_is_semi_sink (GstElement * child, GstBin * bin)
833 {
834 int ret = 1;
836 /* we lock the child here for the remainder of the function to
837 * get its pads and name safely. */
838 GST_LOCK (child);
840 /* check if this is a sink element, these are the elements
841 * without (linked) source pads. */
842 if (child->numsrcpads == 0) {
843 /* shortcut */
844 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
845 "adding child %s as sink", GST_OBJECT_NAME (child));
846 ret = 0;
847 } else {
848 /* loop over all pads, try to figure out if this element
849 * is a semi sink because it has no linked source pads */
850 GList *pads;
851 gboolean connected_src = FALSE;
853 for (pads = child->srcpads; pads; pads = g_list_next (pads)) {
854 GstPad *peer;
856 GST_DEBUG ("looking at pad %p", pads->data);
857 if ((peer = gst_pad_get_peer (GST_PAD_CAST (pads->data)))) {
858 connected_src =
859 gst_object_has_ancestor (GST_OBJECT_CAST (peer),
860 GST_OBJECT_CAST (bin));
861 gst_object_unref (peer);
862 if (connected_src) {
863 break;
864 }
865 }
866 }
867 if (connected_src) {
868 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
869 "not adding child %s as sink: linked source pads",
870 GST_OBJECT_NAME (child));
871 } else {
872 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, bin,
873 "adding child %s as sink since it has unlinked source pads in this bin",
874 GST_OBJECT_NAME (child));
875 ret = 0;
876 }
877 }
878 GST_UNLOCK (child);
880 return ret;
881 }
883 static gint
884 sink_iterator_filter (GstElement * child, GstBin * bin)
885 {
886 if (bin_element_is_sink (child, bin) == 0) {
887 /* returns 0 because this is a GCompareFunc */
888 return 0;
889 } else {
890 /* child carries a ref from gst_bin_iterate_elements -- drop if not passing
891 through */
892 gst_object_unref ((GstObject *) child);
893 return 1;
894 }
895 }
897 /**
898 * gst_bin_iterate_sinks:
899 * @bin: #Gstbin to iterate on
900 *
901 * Get an iterator for the sink elements in this bin.
902 * Each element will have its refcount increased, so unref
903 * after use.
904 *
905 * The sink elements are those without any linked srcpads.
906 *
907 * MT safe.
908 *
909 * Returns: a #GstIterator of #GstElements. gst_iterator_free after use.
910 */
911 GstIterator *
912 gst_bin_iterate_sinks (GstBin * bin)
913 {
914 GstIterator *children;
915 GstIterator *result;
917 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
919 children = gst_bin_iterate_elements (bin);
920 result = gst_iterator_filter (children,
921 (GCompareFunc) sink_iterator_filter, bin);
923 return result;
924 }
926 /* 2 phases:
927 * 1) check state of all children with 0 timeout to find ERROR and
928 * NO_PREROLL elements. return if found.
929 * 2) perform full blocking wait with requested timeout.
930 *
931 * 2) cannot be performed when 1) returns results as the sinks might
932 * not be able to complete the state change making 2) block forever.
933 *
934 * MT safe
935 */
936 static GstStateChangeReturn
937 gst_bin_get_state (GstElement * element, GstState * state,
938 GstState * pending, GTimeVal * timeout)
939 {
940 GstBin *bin = GST_BIN (element);
941 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
942 GList *children;
943 guint32 children_cookie;
944 gboolean have_no_preroll;
946 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "getting state");
948 /* lock bin, no element can be added or removed between going into
949 * the quick scan and the blocking wait. */
950 GST_LOCK (bin);
952 restart:
953 have_no_preroll = FALSE;
955 /* first we need to poll with a non zero timeout to make sure we don't block
956 * on the sinks when we have NO_PREROLL elements. This is why we do
957 * a quick check if there are still NO_PREROLL elements. We also
958 * catch the error elements this way. */
959 {
960 GTimeVal tv;
961 gboolean have_async = FALSE;
963 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "checking for NO_PREROLL");
964 /* use 0 timeout so we don't block on the sinks */
965 GST_TIME_TO_TIMEVAL (0, tv);
966 children = bin->children;
967 children_cookie = bin->children_cookie;
968 while (children) {
969 GstElement *child = GST_ELEMENT_CAST (children->data);
971 gst_object_ref (child);
972 /* now we release the lock to enter a non blocking wait. We
973 * release the lock anyway since we can. */
974 GST_UNLOCK (bin);
976 ret = gst_element_get_state (child, NULL, NULL, &tv);
978 gst_object_unref (child);
980 /* now grab the lock to iterate to the next child */
981 GST_LOCK (bin);
982 if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
983 /* child added/removed during state change, restart. We need
984 * to restart with the quick check as a no-preroll element could
985 * have been added here and we don't want to block on sinks then.*/
986 goto restart;
987 }
989 switch (ret) {
990 /* report FAILURE immediatly */
991 case GST_STATE_CHANGE_FAILURE:
992 goto done;
993 case GST_STATE_CHANGE_NO_PREROLL:
994 /* we have to continue scanning as there might be
995 * ERRORS too */
996 have_no_preroll = TRUE;
997 break;
998 case GST_STATE_CHANGE_ASYNC:
999 have_async = TRUE;
1000 break;
1001 default:
1002 break;
1003 }
1004 children = g_list_next (children);
1005 }
1006 /* if we get here, we have no FAILURES, check for any NO_PREROLL
1007 * elements then. */
1008 if (have_no_preroll) {
1009 ret = GST_STATE_CHANGE_NO_PREROLL;
1010 goto done;
1011 }
1013 /* if we get here, no NO_PREROLL elements are in the pipeline */
1014 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element, "no NO_PREROLL elements");
1016 /* if no ASYNC elements exist we don't even have to poll with a
1017 * timeout again */
1018 if (!have_async) {
1019 ret = GST_STATE_CHANGE_SUCCESS;
1020 goto done;
1021 }
1022 }
1024 /* next we poll all children for their state to see if one of them
1025 * is still busy with its state change. We did not release the bin lock
1026 * yet so the elements are the same as the ones from the quick scan. */
1027 children = bin->children;
1028 children_cookie = bin->children_cookie;
1029 while (children) {
1030 GstElement *child = GST_ELEMENT_CAST (children->data);
1032 gst_object_ref (child);
1033 /* now we release the lock to enter the potentialy blocking wait */
1034 GST_UNLOCK (bin);
1036 /* ret is ASYNC if some child is still performing the state change
1037 * ater the timeout. */
1038 ret = gst_element_get_state (child, NULL, NULL, timeout);
1040 gst_object_unref (child);
1042 /* now grab the lock to iterate to the next child */
1043 GST_LOCK (bin);
1044 if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
1045 /* child added/removed during state change, restart. We need
1046 * to restart with the quick check as a no-preroll element could
1047 * have been added here and we don't want to block on sinks then.*/
1048 goto restart;
1049 }
1051 switch (ret) {
1052 case GST_STATE_CHANGE_SUCCESS:
1053 break;
1054 case GST_STATE_CHANGE_FAILURE:
1055 case GST_STATE_CHANGE_NO_PREROLL:
1056 /* report FAILURE and NO_PREROLL immediatly */
1057 goto done;
1058 case GST_STATE_CHANGE_ASYNC:
1059 goto done;
1060 default:
1061 g_assert_not_reached ();
1062 }
1063 children = g_list_next (children);
1064 }
1065 /* if we got here, all elements can do preroll */
1066 have_no_preroll = FALSE;
1068 done:
1069 GST_UNLOCK (bin);
1071 /* now we can take the state lock, it is possible that new elements
1072 * are added now and we still report the old state. No problem though as
1073 * the return is still consistent, the effect is as if the element was
1074 * added after this function completed. */
1075 GST_STATE_LOCK (bin);
1076 switch (ret) {
1077 case GST_STATE_CHANGE_SUCCESS:
1078 /* we can commit the state */
1079 gst_element_commit_state (element);
1080 break;
1081 case GST_STATE_CHANGE_FAILURE:
1082 /* some element failed, abort the state change */
1083 gst_element_abort_state (element);
1084 break;
1085 default:
1086 /* other cases are just passed along */
1087 break;
1088 }
1090 /* and report the state if needed */
1091 if (state)
1092 *state = GST_STATE (element);
1093 if (pending)
1094 *pending = GST_STATE_PENDING (element);
1096 GST_STATE_NO_PREROLL (element) = have_no_preroll;
1098 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1099 "state current: %s, pending: %s, error: %d, no_preroll: %d, result: %d",
1100 gst_element_state_get_name (GST_STATE (element)),
1101 gst_element_state_get_name (GST_STATE_PENDING (element)),
1102 GST_STATE_ERROR (element), GST_STATE_NO_PREROLL (element), ret);
1104 GST_STATE_UNLOCK (bin);
1106 return ret;
1107 }
1109 /**
1110 * gst_bin_iterate_state_order:
1111 * @bin: #Gstbin to iterate on
1112 *
1113 * Get an iterator for the elements in this bin in the order
1114 * in which a state change should be performed on them. This
1115 * means that first the sinks and then the other elements will
1116 * be returned.
1117 * Each element will have its refcount increased, so unref
1118 * after use.
1119 *
1120 * Not implemented yet.
1121 *
1122 * MT safe.
1123 *
1124 * Returns: a #GstIterator of #GstElements. gst_iterator_free after use.
1125 */
1126 GstIterator *
1127 gst_bin_iterate_state_order (GstBin * bin)
1128 {
1129 GstIterator *result;
1131 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1133 result = NULL;
1135 return result;
1136 }
1138 static void
1139 clear_queue (GQueue * queue, gboolean unref)
1140 {
1141 gpointer p;
1143 while ((p = g_queue_pop_head (queue)))
1144 if (unref)
1145 gst_object_unref (p);
1146 }
1148 static void
1149 remove_all_from_queue (GQueue * queue, gpointer elem, gboolean unref)
1150 {
1151 gpointer p;
1153 while ((p = g_queue_find (queue, elem))) {
1154 if (unref)
1155 gst_object_unref (elem);
1156 g_queue_delete_link (queue, p);
1157 }
1158 }
1160 /* this function is called with the STATE_LOCK held. It works
1161 * as follows:
1162 *
1163 * 1) put all sink elements on the queue.
1164 * 2) put all semisink elements on the queue.
1165 * 3) change state of elements in queue, put linked elements to queue.
1166 * 4) while queue not empty goto 3)
1167 *
1168 * This will effectively change the state of all elements in the bin
1169 * from the sinks to the sources. We have to change the states this
1170 * way so that when a source element pushes data, the downstream element
1171 * is in the right state to receive the data.
1172 *
1173 * MT safe.
1174 */
1175 /* FIXME, make me more elegant, want to use a topological sort algorithm
1176 * based on indegrees (or outdegrees in our case) */
1177 static GstStateChangeReturn
1178 gst_bin_change_state (GstElement * element, GstStateChange transition)
1179 {
1180 GstBin *bin;
1181 GstStateChangeReturn ret;
1182 GstState old_state, pending;
1183 gboolean have_async = FALSE;
1184 gboolean have_no_preroll = FALSE;
1185 GList *children;
1186 guint32 children_cookie;
1187 GQueue *elem_queue; /* list of elements waiting for a state change */
1188 GQueue *semi_queue; /* list of elements with no connected srcpads */
1189 GQueue *temp; /* queue of leftovers */
1190 GstClockTime base_time;
1192 bin = GST_BIN (element);
1194 /* we don't need to take the STATE_LOCK, it is already taken */
1195 old_state = GST_STATE (element);
1196 pending = GST_STATE_PENDING (element);
1198 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1199 "changing state of children from %s to %s",
1200 gst_element_state_get_name (old_state),
1201 gst_element_state_get_name (pending));
1203 if (pending == GST_STATE_VOID_PENDING)
1204 return GST_STATE_CHANGE_SUCCESS;
1206 /* Clear eosed element list on READY-> PAUSED */
1207 if (transition == GST_STATE_CHANGE_READY_TO_PAUSED) {
1208 g_list_free (bin->eosed);
1209 bin->eosed = NULL;
1210 }
1212 /* all elements added to these queues should have their refcount
1213 * incremented */
1214 elem_queue = g_queue_new ();
1215 semi_queue = g_queue_new ();
1216 temp = g_queue_new ();
1218 /* first step, find all sink elements, these are the elements
1219 * without (linked) source pads. */
1220 GST_LOCK (bin);
1222 restart:
1223 /* take base time */
1224 base_time = element->base_time;
1226 /* make sure queues are empty, they could be filled when
1227 * restarting. */
1228 clear_queue (elem_queue, TRUE);
1229 clear_queue (semi_queue, TRUE);
1230 clear_queue (temp, TRUE);
1232 children = bin->children;
1233 children_cookie = bin->children_cookie;
1234 GST_DEBUG_OBJECT (bin, "reffing and examining children");
1235 while (children) {
1236 GstElement *child = GST_ELEMENT_CAST (children->data);
1238 gst_object_ref (child);
1239 GST_UNLOCK (bin);
1241 if (bin_element_is_sink (child, bin) == 0) {
1242 g_queue_push_tail (elem_queue, child);
1243 } else if (bin_element_is_semi_sink (child, bin) == 0) {
1244 g_queue_push_tail (semi_queue, child);
1245 } else {
1246 g_queue_push_tail (temp, child);
1247 }
1249 GST_LOCK (bin);
1250 if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
1251 GST_INFO_OBJECT (bin, "bin->children_cookie changed, restarting");
1252 /* restart will unref the children in the queues so that we don't
1253 * leak refcounts. */
1254 goto restart;
1255 }
1256 children = g_list_next (children);
1257 }
1258 GST_DEBUG_OBJECT (bin, "reffed and examined children");
1259 GST_UNLOCK (bin);
1261 /* after this point new elements can be added/removed from the
1262 * bin. We operate on the snapshot taken above. Applications
1263 * should serialize their add/remove and set_state. */
1265 /* if we don't have real sinks, we continue with the other elements, there
1266 * has to be at least one element in the semi queue. */
1267 if (g_queue_is_empty (elem_queue) && !g_queue_is_empty (semi_queue)) {
1268 GQueue *q = elem_queue;
1270 /* we swap the queues as oposed to copy them over */
1271 elem_queue = semi_queue;
1272 semi_queue = q;
1273 }
1275 /* second step, change state of elements in the queue */
1276 GST_DEBUG_OBJECT (bin, "change state of elements in the queue");
1277 while (!g_queue_is_empty (elem_queue)) {
1278 GstElement *qelement;
1279 GList *pads;
1280 gboolean locked;
1282 /* take element */
1283 qelement = g_queue_pop_head (elem_queue);
1284 /* we don't need any duplicates in the other queue anymore */
1285 remove_all_from_queue (semi_queue, qelement, TRUE);
1286 remove_all_from_queue (temp, qelement, TRUE);
1288 /* queue all elements connected to the sinkpads of this element */
1289 GST_LOCK (qelement);
1290 pads = qelement->sinkpads;
1291 while (pads) {
1292 GstPad *pad = GST_PAD_CAST (pads->data);
1293 GstPad *peer;
1295 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1296 "found sinkpad %s:%s", GST_DEBUG_PAD_NAME (pad));
1298 peer = gst_pad_get_peer (pad);
1299 if (peer) {
1300 GstObject *peer_parent;
1302 /* get parent */
1303 peer_parent = gst_object_get_parent (GST_OBJECT (peer));
1305 /* if we have an element parent, follow it */
1306 if (peer_parent && GST_IS_ELEMENT (peer_parent)) {
1307 GstObject *parent;
1309 /* see if this element is in the bin we are currently handling */
1310 parent = gst_object_get_parent (peer_parent);
1311 if (parent) {
1312 if (parent == GST_OBJECT_CAST (bin)) {
1313 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1314 "adding element %s to queue", GST_ELEMENT_NAME (peer_parent));
1316 /* make sure we don't have duplicates */
1317 remove_all_from_queue (semi_queue, peer_parent, TRUE);
1318 remove_all_from_queue (elem_queue, peer_parent, TRUE);
1319 remove_all_from_queue (temp, peer_parent, TRUE);
1321 /* was reffed before pushing on the queue by the
1322 * gst_object_get_parent() call we used to get the element. */
1323 g_queue_push_tail (elem_queue, peer_parent);
1324 /* so that we don't unref it */
1325 peer_parent = NULL;
1326 } else {
1327 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1328 "not adding element %s to queue, it is in another bin",
1329 GST_ELEMENT_NAME (peer_parent));
1330 }
1331 gst_object_unref (parent);
1332 }
1333 }
1334 if (peer_parent)
1335 gst_object_unref (peer_parent);
1337 gst_object_unref (peer);
1338 } else {
1339 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1340 "pad %s:%s does not have a peer", GST_DEBUG_PAD_NAME (pad));
1341 }
1342 pads = g_list_next (pads);
1343 }
1344 /* peel off the locked flag and release the element lock */
1345 locked = GST_FLAG_IS_SET (qelement, GST_ELEMENT_LOCKED_STATE);
1346 GST_UNLOCK (qelement);
1348 /* skip locked elements */
1349 if (G_UNLIKELY (locked))
1350 goto next_element;
1352 /* set base time on element */
1353 gst_element_set_base_time (qelement, base_time);
1355 /* then change state */
1356 ret = gst_element_set_state (qelement, pending);
1358 /* the set state could have cause elements to be added/removed,
1359 * we support that. */
1360 GST_LOCK (bin);
1361 if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
1362 gst_object_unref (qelement);
1363 goto restart;
1364 }
1365 GST_UNLOCK (bin);
1367 switch (ret) {
1368 case GST_STATE_CHANGE_SUCCESS:
1369 GST_CAT_DEBUG (GST_CAT_STATES,
1370 "child '%s' changed state to %d(%s) successfully",
1371 GST_ELEMENT_NAME (qelement), pending,
1372 gst_element_state_get_name (pending));
1373 break;
1374 case GST_STATE_CHANGE_ASYNC:
1375 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1376 "child '%s' is changing state asynchronously",
1377 GST_ELEMENT_NAME (qelement));
1378 have_async = TRUE;
1379 break;
1380 case GST_STATE_CHANGE_FAILURE:
1381 GST_CAT_INFO_OBJECT (GST_CAT_STATES, element,
1382 "child '%s' failed to go to state %d(%s)",
1383 GST_ELEMENT_NAME (qelement),
1384 pending, gst_element_state_get_name (pending));
1385 ret = GST_STATE_CHANGE_FAILURE;
1386 /* release refcount of element we popped off the queue */
1387 gst_object_unref (qelement);
1388 goto exit;
1389 case GST_STATE_CHANGE_NO_PREROLL:
1390 GST_CAT_DEBUG (GST_CAT_STATES,
1391 "child '%s' changed state to %d(%s) successfully without preroll",
1392 GST_ELEMENT_NAME (qelement), pending,
1393 gst_element_state_get_name (pending));
1394 have_no_preroll = TRUE;
1395 break;
1396 default:
1397 g_assert_not_reached ();
1398 break;
1399 }
1400 next_element:
1401 gst_object_unref (qelement);
1403 /* if queue is empty now, continue with a non-sink */
1404 if (g_queue_is_empty (elem_queue)) {
1405 GstElement *non_sink;
1407 GST_DEBUG ("sinks and upstream elements exhausted");
1408 non_sink = g_queue_pop_head (semi_queue);
1409 if (non_sink) {
1410 GST_DEBUG ("found lefover semi-sink %s", GST_OBJECT_NAME (non_sink));
1411 g_queue_push_tail (elem_queue, non_sink);
1412 } else {
1413 non_sink = g_queue_pop_head (temp);
1414 if (non_sink) {
1415 GST_DEBUG ("found lefover non-sink %s", GST_OBJECT_NAME (non_sink));
1416 g_queue_push_tail (elem_queue, non_sink);
1417 }
1418 }
1419 }
1420 }
1422 if (have_no_preroll) {
1423 ret = GST_STATE_CHANGE_NO_PREROLL;
1424 } else if (have_async) {
1425 ret = GST_STATE_CHANGE_ASYNC;
1426 } else {
1427 ret = parent_class->change_state (element, transition);
1428 }
1430 GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
1431 "done changing bin's state from %s to %s, now in %s, ret %d",
1432 gst_element_state_get_name (old_state),
1433 gst_element_state_get_name (pending),
1434 gst_element_state_get_name (GST_STATE (element)), ret);
1436 exit:
1437 /* release refcounts in queue, should normally be empty unless we
1438 * had an error. */
1439 clear_queue (elem_queue, TRUE);
1440 clear_queue (semi_queue, TRUE);
1441 clear_queue (temp, TRUE);
1442 g_queue_free (elem_queue);
1443 g_queue_free (semi_queue);
1444 g_queue_free (temp);
1446 return ret;
1447 }
1449 static void
1450 gst_bin_dispose (GObject * object)
1451 {
1452 GstBin *bin = GST_BIN (object);
1454 GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
1456 /* ref to not hit 0 again */
1457 gst_object_ref (object);
1459 g_list_free (bin->eosed);
1460 bin->eosed = NULL;
1461 gst_object_unref (bin->child_bus);
1462 bin->child_bus = NULL;
1463 gst_element_set_bus (GST_ELEMENT (bin), NULL);
1465 while (bin->children) {
1466 gst_bin_remove (bin, GST_ELEMENT (bin->children->data));
1467 }
1468 GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose no children");
1469 g_assert (bin->children == NULL);
1470 g_assert (bin->numchildren == 0);
1472 G_OBJECT_CLASS (parent_class)->dispose (object);
1473 }
1475 /*
1476 * This function is a utility event handler for seek events.
1477 * It will send the event to all sinks.
1478 * Applications are free to override this behaviour and
1479 * implement their own seek handler, but this will work for
1480 * pretty much all cases in practice.
1481 */
1482 static gboolean
1483 gst_bin_send_event (GstElement * element, GstEvent * event)
1484 {
1485 GstBin *bin = GST_BIN (element);
1486 GstIterator *iter;
1487 gboolean res = TRUE;
1488 gboolean done = FALSE;
1490 iter = gst_bin_iterate_sinks (bin);
1491 GST_DEBUG_OBJECT (bin, "Sending event to sink children");
1493 while (!done) {
1494 gpointer data;
1496 switch (gst_iterator_next (iter, &data)) {
1497 case GST_ITERATOR_OK:
1498 {
1499 GstElement *sink;
1501 gst_event_ref (event);
1502 sink = GST_ELEMENT_CAST (data);
1503 res &= gst_element_send_event (sink, event);
1504 gst_object_unref (sink);
1505 break;
1506 }
1507 case GST_ITERATOR_RESYNC:
1508 gst_iterator_resync (iter);
1509 res = TRUE;
1510 break;
1511 default:
1512 case GST_ITERATOR_DONE:
1513 done = TRUE;
1514 break;
1515 }
1516 }
1517 gst_iterator_free (iter);
1518 gst_event_unref (event);
1520 return res;
1521 }
1523 static GstBusSyncReply
1524 bin_bus_handler (GstBus * bus, GstMessage * message, GstBin * bin)
1525 {
1526 GST_DEBUG_OBJECT (bin, "[msg %p] handling child message of type %d",
1527 message, GST_MESSAGE_TYPE (message));
1529 switch (GST_MESSAGE_TYPE (message)) {
1530 case GST_MESSAGE_EOS:{
1531 GstObject *src = GST_MESSAGE_SRC (message);
1533 if (src) {
1534 gchar *name;
1536 name = gst_object_get_name (src);
1537 GST_DEBUG_OBJECT (bin, "got EOS message from %s", name);
1538 g_free (name);
1540 /* collect all eos messages from the children */
1541 GST_LOCK (bin->child_bus);
1542 bin->eosed = g_list_prepend (bin->eosed, src);
1543 GST_UNLOCK (bin->child_bus);
1545 /* if we are completely EOS, we forward an EOS message */
1546 if (is_eos (bin)) {
1547 GST_DEBUG_OBJECT (bin, "all sinks posted EOS");
1548 gst_element_post_message (GST_ELEMENT (bin),
1549 gst_message_new_eos (GST_OBJECT (bin)));
1550 }
1551 } else {
1552 GST_DEBUG_OBJECT (bin, "got EOS message from (NULL), not processing");
1553 }
1555 /* we drop all EOS messages */
1556 gst_message_unref (message);
1557 break;
1558 }
1559 default:
1560 /* Send all other messages upward */
1561 GST_DEBUG_OBJECT (bin, "posting message upward");
1562 gst_element_post_message (GST_ELEMENT (bin), message);
1563 break;
1564 }
1566 return GST_BUS_DROP;
1567 }
1569 static gboolean
1570 gst_bin_query (GstElement * element, GstQuery * query)
1571 {
1572 GstBin *bin = GST_BIN (element);
1573 GstIterator *iter;
1574 gboolean res = FALSE, done = FALSE;
1576 iter = gst_bin_iterate_sinks (bin);
1577 GST_DEBUG_OBJECT (bin, "Sending event to sink children");
1579 while (!(res || done)) {
1580 gpointer data;
1582 switch (gst_iterator_next (iter, &data)) {
1583 case GST_ITERATOR_OK:
1584 {
1585 GstElement *sink;
1587 sink = GST_ELEMENT_CAST (data);
1588 res = gst_element_query (sink, query);
1589 gst_object_unref (sink);
1590 break;
1591 }
1592 case GST_ITERATOR_RESYNC:
1593 gst_iterator_resync (iter);
1594 break;
1595 default:
1596 case GST_ITERATOR_DONE:
1597 done = TRUE;
1598 break;
1599 }
1600 }
1601 gst_iterator_free (iter);
1603 return res;
1604 }
1606 static gint
1607 compare_name (GstElement * element, const gchar * name)
1608 {
1609 gint eq;
1611 GST_LOCK (element);
1612 eq = strcmp (GST_ELEMENT_NAME (element), name);
1613 GST_UNLOCK (element);
1615 if (eq != 0) {
1616 gst_object_unref (element);
1617 }
1618 return eq;
1619 }
1621 /**
1622 * gst_bin_get_by_name:
1623 * @bin: #Gstbin to search
1624 * @name: the element name to search for
1625 *
1626 * Get the element with the given name from this bin. This
1627 * function recurses into subbins.
1628 *
1629 * MT safe.
1630 *
1631 * Returns: the element with the given name. Returns NULL if the
1632 * element is not found or when bad parameters were given. Unref after
1633 * use.
1634 */
1635 GstElement *
1636 gst_bin_get_by_name (GstBin * bin, const gchar * name)
1637 {
1638 GstIterator *children;
1639 GstIterator *result;
1641 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1643 GST_CAT_INFO (GST_CAT_PARENTAGE, "[%s]: looking up child element %s",
1644 GST_ELEMENT_NAME (bin), name);
1646 children = gst_bin_iterate_recurse (bin);
1647 result = gst_iterator_find_custom (children,
1648 (GCompareFunc) compare_name, (gpointer) name);
1649 gst_iterator_free (children);
1651 return GST_ELEMENT_CAST (result);
1652 }
1654 /**
1655 * gst_bin_get_by_name_recurse_up:
1656 * @bin: #Gstbin to search
1657 * @name: the element name to search for
1658 *
1659 * MT safe.
1660 *
1661 * Get the element with the given name from this bin. If the
1662 * element is not found, a recursion is performed on the parent bin.
1663 *
1664 * Returns: the element with the given name or NULL when the element
1665 * was not found or bad parameters were given. Unref after use.
1666 */
1667 GstElement *
1668 gst_bin_get_by_name_recurse_up (GstBin * bin, const gchar * name)
1669 {
1670 GstElement *result;
1672 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1673 g_return_val_if_fail (name != NULL, NULL);
1675 result = gst_bin_get_by_name (bin, name);
1677 if (!result) {
1678 GstObject *parent;
1680 parent = gst_object_get_parent (GST_OBJECT_CAST (bin));
1681 if (parent) {
1682 if (GST_IS_BIN (parent)) {
1683 result = gst_bin_get_by_name_recurse_up (GST_BIN_CAST (parent), name);
1684 }
1685 gst_object_unref (parent);
1686 }
1687 }
1689 return result;
1690 }
1692 static gint
1693 compare_interface (GstElement * element, gpointer interface)
1694 {
1695 gint ret;
1697 if (G_TYPE_CHECK_INSTANCE_TYPE (element, GPOINTER_TO_INT (interface))) {
1698 ret = 0;
1699 } else {
1700 /* we did not find the element, need to release the ref
1701 * added by the iterator */
1702 gst_object_unref (element);
1703 ret = 1;
1704 }
1705 return ret;
1706 }
1708 /**
1709 * gst_bin_get_by_interface:
1710 * @bin: bin to find element in
1711 * @interface: interface to be implemented by interface
1712 *
1713 * Looks for the first element inside the bin that implements the given
1714 * interface. If such an element is found, it returns the element. You can
1715 * cast this element to the given interface afterwards.
1716 * If you want all elements that implement the interface, use
1717 * gst_bin_iterate_all_by_interface(). The function recurses inside bins.
1718 *
1719 * MT safe.
1720 *
1721 * Returns: An #GstElement inside the bin implementing the interface.
1722 * Unref after use.
1723 */
1724 GstElement *
1725 gst_bin_get_by_interface (GstBin * bin, GType interface)
1726 {
1727 GstIterator *children;
1728 GstIterator *result;
1730 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1732 children = gst_bin_iterate_recurse (bin);
1733 result = gst_iterator_find_custom (children, (GCompareFunc) compare_interface,
1734 GINT_TO_POINTER (interface));
1735 gst_iterator_free (children);
1737 return GST_ELEMENT_CAST (result);
1738 }
1740 /**
1741 * gst_bin_iterate_all_by_interface:
1742 * @bin: bin to find elements in
1743 * @interface: interface to be implemented by interface
1744 *
1745 * Looks for all elements inside the bin that implements the given
1746 * interface. You can safely cast all returned elements to the given interface.
1747 * The function recurses bins inside bins. The iterator will return a series
1748 * of #GstElement that should be unreffed after use.
1749 *
1750 * MT safe.
1751 *
1752 * Returns: A #GstIterator for the elements inside the bin implementing the
1753 * given interface.
1754 */
1755 GstIterator *
1756 gst_bin_iterate_all_by_interface (GstBin * bin, GType interface)
1757 {
1758 GstIterator *children;
1759 GstIterator *result;
1761 g_return_val_if_fail (GST_IS_BIN (bin), NULL);
1763 children = gst_bin_iterate_recurse (bin);
1764 result = gst_iterator_filter (children, (GCompareFunc) compare_interface,
1765 GINT_TO_POINTER (interface));
1767 return result;
1768 }
1770 #ifndef GST_DISABLE_LOADSAVE
1771 static xmlNodePtr
1772 gst_bin_save_thyself (GstObject * object, xmlNodePtr parent)
1773 {
1774 GstBin *bin = GST_BIN (object);
1775 xmlNodePtr childlist, elementnode;
1776 GList *children;
1777 GstElement *child;
1779 if (GST_OBJECT_CLASS (parent_class)->save_thyself)
1780 GST_OBJECT_CLASS (parent_class)->save_thyself (GST_OBJECT (bin), parent);
1782 childlist = xmlNewChild (parent, NULL, (xmlChar *) "children", NULL);
1784 GST_CAT_INFO (GST_CAT_XML, "[%s]: saving %d children",
1785 GST_ELEMENT_NAME (bin), bin->numchildren);
1787 children = bin->children;
1788 while (children) {
1789 child = GST_ELEMENT (children->data);
1790 elementnode = xmlNewChild (childlist, NULL, (xmlChar *) "element", NULL);
1791 gst_object_save_thyself (GST_OBJECT (child), elementnode);
1792 children = g_list_next (children);
1793 }
1794 return childlist;
1795 }
1797 static void
1798 gst_bin_restore_thyself (GstObject * object, xmlNodePtr self)
1799 {
1800 GstBin *bin = GST_BIN (object);
1801 xmlNodePtr field = self->xmlChildrenNode;
1802 xmlNodePtr childlist;
1804 while (field) {
1805 if (!strcmp ((char *) field->name, "children")) {
1806 GST_CAT_INFO (GST_CAT_XML, "[%s]: loading children",
1807 GST_ELEMENT_NAME (object));
1808 childlist = field->xmlChildrenNode;
1809 while (childlist) {
1810 if (!strcmp ((char *) childlist->name, "element")) {
1811 GstElement *element =
1812 gst_xml_make_element (childlist, GST_OBJECT (bin));
1814 /* it had to be parented to find the pads, now we ref and unparent so
1815 * we can add it to the bin */
1816 gst_object_ref (element);
1817 gst_object_unparent (GST_OBJECT (element));
1819 gst_bin_add (bin, element);
1820 }
1821 childlist = childlist->next;
1822 }
1823 }
1825 field = field->next;
1826 }
1827 if (GST_OBJECT_CLASS (parent_class)->restore_thyself)
1828 (GST_OBJECT_CLASS (parent_class)->restore_thyself) (object, self);
1829 }
1830 #endif /* GST_DISABLE_LOADSAVE */