2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
4 * 2005 Andy Wingo <wingo@pobox.com>
5 * 2006 Edward Hervey <bilboed@bilboed.com>
7 * gstghostpad.c: Proxy pads
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Library General Public
11 * License as published by the Free Software Foundation; either
12 * version 2 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Library General Public License for more details.
19 * You should have received a copy of the GNU Library General Public
20 * License along with this library; if not, write to the
21 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
22 * Boston, MA 02110-1301, USA.
27 * @short_description: Pseudo link pads
30 * GhostPads are useful when organizing pipelines with #GstBin like elements.
31 * The idea here is to create hierarchical element graphs. The bin element
32 * contains a sub-graph. Now one would like to treat the bin-element like any
33 * other #GstElement. This is where GhostPads come into play. A GhostPad acts as
34 * a proxy for another pad. Thus the bin can have sink and source ghost-pads
35 * that are associated with sink and source pads of the child elements.
37 * If the target pad is known at creation time, gst_ghost_pad_new() is the
38 * function to use to get a ghost-pad. Otherwise one can use gst_ghost_pad_new_no_target()
39 * to create the ghost-pad and use gst_ghost_pad_set_target() to establish the
40 * association later on.
42 * Note that GhostPads add overhead to the data processing of a pipeline.
45 #include "gst_private.h"
48 #include "gstghostpad.h"
51 #define GST_CAT_DEFAULT GST_CAT_PADS
53 #define GST_PROXY_PAD_CAST(obj) ((GstProxyPad *)obj)
54 #define GST_PROXY_PAD_PRIVATE(obj) (GST_PROXY_PAD_CAST (obj)->priv)
55 #define GST_PROXY_PAD_TARGET(pad) (GST_PAD_PEER (GST_PROXY_PAD_INTERNAL (pad)))
56 #define GST_PROXY_PAD_INTERNAL(pad) (GST_PROXY_PAD_PRIVATE (pad)->internal)
58 #define GST_PROXY_PAD_ACQUIRE_INTERNAL(pad, internal, retval) \
60 GST_PAD_CAST (gst_proxy_pad_get_internal (GST_PROXY_PAD_CAST (pad))); \
61 if (internal == NULL) \
64 #define GST_PROXY_PAD_RELEASE_INTERNAL(internal) gst_object_unref (internal);
66 struct _GstProxyPadPrivate
71 G_DEFINE_TYPE (GstProxyPad, gst_proxy_pad, GST_TYPE_PAD);
73 static GstPad *gst_proxy_pad_get_target (GstPad * pad);
76 * gst_proxy_pad_iterate_internal_links_default:
77 * @pad: the #GstPad to get the internal links of.
78 * @parent: (allow-none): the parent of @pad or %NULL
80 * Invoke the default iterate internal links function of the proxy pad.
82 * Returns: (nullable): a #GstIterator of #GstPad, or %NULL if @pad
83 * has no parent. Unref each returned pad with gst_object_unref().
86 gst_proxy_pad_iterate_internal_links_default (GstPad * pad, GstObject * parent)
88 GstIterator *res = NULL;
92 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), NULL);
94 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, NULL);
96 g_value_init (&v, GST_TYPE_PAD);
97 g_value_take_object (&v, internal);
98 res = gst_iterator_new_single (GST_TYPE_PAD, &v);
105 * gst_proxy_pad_chain_default:
106 * @pad: a sink #GstPad, returns GST_FLOW_ERROR if not.
107 * @parent: (allow-none): the parent of @pad or %NULL
108 * @buffer: (transfer full): the #GstBuffer to send, return GST_FLOW_ERROR
111 * Invoke the default chain function of the proxy pad.
113 * Returns: a #GstFlowReturn from the pad.
116 gst_proxy_pad_chain_default (GstPad * pad, GstObject * parent,
122 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
123 g_return_val_if_fail (GST_IS_BUFFER (buffer), GST_FLOW_ERROR);
125 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, GST_FLOW_NOT_LINKED);
126 res = gst_pad_push (internal, buffer);
127 GST_PROXY_PAD_RELEASE_INTERNAL (internal);
133 * gst_proxy_pad_chain_list_default:
134 * @pad: a sink #GstPad, returns GST_FLOW_ERROR if not.
135 * @parent: (allow-none): the parent of @pad or %NULL
136 * @list: (transfer full): the #GstBufferList to send, return GST_FLOW_ERROR
139 * Invoke the default chain list function of the proxy pad.
141 * Returns: a #GstFlowReturn from the pad.
144 gst_proxy_pad_chain_list_default (GstPad * pad, GstObject * parent,
145 GstBufferList * list)
150 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
151 g_return_val_if_fail (GST_IS_BUFFER_LIST (list), GST_FLOW_ERROR);
153 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, GST_FLOW_NOT_LINKED);
154 res = gst_pad_push_list (internal, list);
155 GST_PROXY_PAD_RELEASE_INTERNAL (internal);
161 * gst_proxy_pad_getrange_default:
162 * @pad: a src #GstPad, returns #GST_FLOW_ERROR if not.
163 * @parent: the parent of @pad
164 * @offset: The start offset of the buffer
165 * @size: The length of the buffer
166 * @buffer: (out callee-allocates): a pointer to hold the #GstBuffer,
167 * returns #GST_FLOW_ERROR if %NULL.
169 * Invoke the default getrange function of the proxy pad.
171 * Returns: a #GstFlowReturn from the pad.
174 gst_proxy_pad_getrange_default (GstPad * pad, GstObject * parent,
175 guint64 offset, guint size, GstBuffer ** buffer)
180 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
181 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
183 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, GST_FLOW_NOT_LINKED);
184 res = gst_pad_pull_range (internal, offset, size, buffer);
185 GST_PROXY_PAD_RELEASE_INTERNAL (internal);
191 gst_proxy_pad_get_target (GstPad * pad)
195 GST_OBJECT_LOCK (pad);
196 target = gst_pad_get_peer (GST_PROXY_PAD_INTERNAL (pad));
197 GST_OBJECT_UNLOCK (pad);
203 * gst_proxy_pad_get_internal:
204 * @pad: the #GstProxyPad
206 * Get the internal pad of @pad. Unref target pad after usage.
208 * The internal pad of a #GstGhostPad is the internally used
209 * pad of opposite direction, which is used to link to the target.
211 * Returns: (transfer full) (nullable): the target #GstProxyPad, can
212 * be %NULL. Unref target pad after usage.
215 gst_proxy_pad_get_internal (GstProxyPad * pad)
219 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), NULL);
221 GST_OBJECT_LOCK (pad);
222 internal = GST_PROXY_PAD_INTERNAL (pad);
224 gst_object_ref (internal);
225 GST_OBJECT_UNLOCK (pad);
227 return GST_PROXY_PAD_CAST (internal);
231 gst_proxy_pad_class_init (GstProxyPadClass * klass)
233 g_type_class_add_private (klass, sizeof (GstProxyPadPrivate));
235 /* Register common function pointer descriptions */
236 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_iterate_internal_links_default);
237 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_chain_default);
238 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_chain_list_default);
239 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_getrange_default);
243 gst_proxy_pad_init (GstProxyPad * ppad)
245 GstPad *pad = (GstPad *) ppad;
247 GST_PROXY_PAD_PRIVATE (ppad) = G_TYPE_INSTANCE_GET_PRIVATE (ppad,
248 GST_TYPE_PROXY_PAD, GstProxyPadPrivate);
250 gst_pad_set_iterate_internal_links_function (pad,
251 gst_proxy_pad_iterate_internal_links_default);
253 GST_PAD_SET_PROXY_CAPS (pad);
254 GST_PAD_SET_PROXY_SCHEDULING (pad);
255 GST_PAD_SET_PROXY_ALLOCATION (pad);
259 /***********************************************************************
260 * Ghost pads, implemented as a pair of proxy pads (sort of)
264 #define GST_GHOST_PAD_PRIVATE(obj) (GST_GHOST_PAD_CAST (obj)->priv)
266 struct _GstGhostPadPrivate
268 /* with PROXY_LOCK */
269 gboolean constructed;
272 G_DEFINE_TYPE (GstGhostPad, gst_ghost_pad, GST_TYPE_PROXY_PAD);
274 static void gst_ghost_pad_dispose (GObject * object);
277 gst_ghost_pad_internal_activate_push_default (GstPad * pad, GstObject * parent,
284 gst_ghost_pad_internal_activate_pull_default (GstPad * pad, GstObject * parent,
290 GST_LOG_OBJECT (pad, "%sactivate pull on %s:%s", (active ? "" : "de"),
291 GST_DEBUG_PAD_NAME (pad));
293 if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
294 /* we are activated in pull mode by our peer element, which is a sinkpad
295 * that wants to operate in pull mode. This activation has to propagate
296 * upstream through the pipeline. We call the internal activation function,
297 * which will trigger gst_ghost_pad_activate_pull_default, which propagates even
298 * further upstream */
299 GST_LOG_OBJECT (pad, "pad is src, activate internal");
300 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
301 ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
302 GST_PROXY_PAD_RELEASE_INTERNAL (other);
303 } else if (G_LIKELY ((other = gst_pad_get_peer (pad)))) {
304 /* We are SINK, the ghostpad is SRC, we propagate the activation upstream
305 * since we hold a pointer to the upstream peer. */
306 GST_LOG_OBJECT (pad, "activating peer");
307 ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
308 gst_object_unref (other);
310 /* this is failure, we can't activate pull if there is no peer */
311 GST_LOG_OBJECT (pad, "not src and no peer, failing");
314 GST_LOG_OBJECT (pad, "deactivating pull, with no peer - allowing");
322 * gst_ghost_pad_internal_activate_mode_default:
323 * @pad: the #GstPad to activate or deactivate.
324 * @parent: (allow-none): the parent of @pad or %NULL
325 * @mode: the requested activation mode
326 * @active: whether the pad should be active or not.
328 * Invoke the default activate mode function of a proxy pad that is
329 * owned by a ghost pad.
331 * Returns: %TRUE if the operation was successful.
334 gst_ghost_pad_internal_activate_mode_default (GstPad * pad, GstObject * parent,
335 GstPadMode mode, gboolean active)
339 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
342 case GST_PAD_MODE_PULL:
343 res = gst_ghost_pad_internal_activate_pull_default (pad, parent, active);
345 case GST_PAD_MODE_PUSH:
346 res = gst_ghost_pad_internal_activate_push_default (pad, parent, active);
349 GST_LOG_OBJECT (pad, "unknown activation mode %d", mode);
357 gst_ghost_pad_activate_push_default (GstPad * pad, GstObject * parent,
363 g_return_val_if_fail (GST_IS_GHOST_PAD (pad), FALSE);
365 GST_LOG_OBJECT (pad, "%sactivate push on %s:%s, proxy internal",
366 (active ? "" : "de"), GST_DEBUG_PAD_NAME (pad));
368 /* just activate the internal pad */
369 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
370 ret = gst_pad_activate_mode (other, GST_PAD_MODE_PUSH, active);
371 GST_PROXY_PAD_RELEASE_INTERNAL (other);
377 gst_ghost_pad_activate_pull_default (GstPad * pad, GstObject * parent,
383 GST_LOG_OBJECT (pad, "%sactivate pull on %s:%s", (active ? "" : "de"),
384 GST_DEBUG_PAD_NAME (pad));
386 if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
387 /* the ghostpad is SRC and activated in pull mode by its peer, call the
388 * activation function of the internal pad to propagate the activation
390 GST_LOG_OBJECT (pad, "pad is src, activate internal");
391 GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
392 ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
393 GST_PROXY_PAD_RELEASE_INTERNAL (other);
394 } else if (G_LIKELY ((other = gst_pad_get_peer (pad)))) {
395 /* We are SINK and activated by the internal pad, propagate activation
396 * upstream because we hold a ref to the upstream peer */
397 GST_LOG_OBJECT (pad, "activating peer");
398 ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
399 gst_object_unref (other);
401 /* this is failure, we can't activate pull if there is no peer */
402 GST_LOG_OBJECT (pad, "not src and no peer, failing");
405 GST_LOG_OBJECT (pad, "deactivating pull, with no peer - allowing");
413 * gst_ghost_pad_activate_mode_default:
414 * @pad: the #GstPad to activate or deactivate.
415 * @parent: (allow-none): the parent of @pad or %NULL
416 * @mode: the requested activation mode
417 * @active: whether the pad should be active or not.
419 * Invoke the default activate mode function of a ghost pad.
421 * Returns: %TRUE if the operation was successful.
424 gst_ghost_pad_activate_mode_default (GstPad * pad, GstObject * parent,
425 GstPadMode mode, gboolean active)
429 g_return_val_if_fail (GST_IS_GHOST_PAD (pad), FALSE);
432 case GST_PAD_MODE_PULL:
433 res = gst_ghost_pad_activate_pull_default (pad, parent, active);
435 case GST_PAD_MODE_PUSH:
436 res = gst_ghost_pad_activate_push_default (pad, parent, active);
439 GST_LOG_OBJECT (pad, "unknown activation mode %d", mode);
447 gst_ghost_pad_class_init (GstGhostPadClass * klass)
449 GObjectClass *gobject_class = (GObjectClass *) klass;
451 g_type_class_add_private (klass, sizeof (GstGhostPadPrivate));
453 gobject_class->dispose = gst_ghost_pad_dispose;
455 GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_activate_pull_default);
456 GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_activate_push_default);
460 gst_ghost_pad_init (GstGhostPad * pad)
462 GST_GHOST_PAD_PRIVATE (pad) = G_TYPE_INSTANCE_GET_PRIVATE (pad,
463 GST_TYPE_GHOST_PAD, GstGhostPadPrivate);
465 gst_pad_set_activatemode_function (GST_PAD_CAST (pad),
466 gst_ghost_pad_activate_mode_default);
470 gst_ghost_pad_dispose (GObject * object)
476 pad = GST_PAD (object);
478 GST_DEBUG_OBJECT (pad, "dispose");
480 gst_ghost_pad_set_target (GST_GHOST_PAD (pad), NULL);
482 /* Unlink here so that gst_pad_dispose doesn't. That would lead to a call to
483 * gst_ghost_pad_unlink_default when the ghost pad is in an inconsistent state */
484 peer = gst_pad_get_peer (pad);
486 if (GST_PAD_IS_SRC (pad))
487 gst_pad_unlink (pad, peer);
489 gst_pad_unlink (peer, pad);
491 gst_object_unref (peer);
494 GST_OBJECT_LOCK (pad);
495 internal = GST_PROXY_PAD_INTERNAL (pad);
497 gst_pad_set_activatemode_function (internal, NULL);
499 /* disposes of the internal pad, since the ghostpad is the only possible object
500 * that has a refcount on the internal pad. */
501 gst_object_unparent (GST_OBJECT_CAST (internal));
502 GST_PROXY_PAD_INTERNAL (pad) = NULL;
504 GST_OBJECT_UNLOCK (pad);
506 G_OBJECT_CLASS (gst_ghost_pad_parent_class)->dispose (object);
510 * gst_ghost_pad_construct:
511 * @gpad: the newly allocated ghost pad
513 * Finish initialization of a newly allocated ghost pad.
515 * This function is most useful in language bindings and when subclassing
516 * #GstGhostPad; plugin and application developers normally will not call this
517 * function. Call this function directly after a call to g_object_new
518 * (GST_TYPE_GHOST_PAD, "direction", @dir, ..., NULL).
520 * Returns: %TRUE if the construction succeeds, %FALSE otherwise.
523 gst_ghost_pad_construct (GstGhostPad * gpad)
525 GstPadDirection dir, otherdir;
526 GstPadTemplate *templ;
527 GstPad *pad, *internal;
529 g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);
530 g_return_val_if_fail (!GST_GHOST_PAD_PRIVATE (gpad)->constructed, FALSE);
532 g_object_get (gpad, "direction", &dir, "template", &templ, NULL);
534 g_return_val_if_fail (dir != GST_PAD_UNKNOWN, FALSE);
536 pad = GST_PAD (gpad);
538 /* Set directional padfunctions for ghostpad */
539 if (dir == GST_PAD_SINK) {
540 gst_pad_set_chain_function (pad, gst_proxy_pad_chain_default);
541 gst_pad_set_chain_list_function (pad, gst_proxy_pad_chain_list_default);
543 gst_pad_set_getrange_function (pad, gst_proxy_pad_getrange_default);
546 /* INTERNAL PAD, it always exists and is child of the ghostpad */
547 otherdir = (dir == GST_PAD_SRC) ? GST_PAD_SINK : GST_PAD_SRC;
550 g_object_new (GST_TYPE_PROXY_PAD, "name", NULL,
551 "direction", otherdir, "template", templ, NULL);
552 /* release ref obtained via g_object_get */
553 gst_object_unref (templ);
556 g_object_new (GST_TYPE_PROXY_PAD, "name", NULL,
557 "direction", otherdir, NULL);
559 GST_PAD_UNSET_FLUSHING (internal);
561 /* Set directional padfunctions for internal pad */
562 if (dir == GST_PAD_SRC) {
563 gst_pad_set_chain_function (internal, gst_proxy_pad_chain_default);
564 gst_pad_set_chain_list_function (internal,
565 gst_proxy_pad_chain_list_default);
567 gst_pad_set_getrange_function (internal, gst_proxy_pad_getrange_default);
570 GST_OBJECT_LOCK (pad);
572 /* now make the ghostpad a parent of the internal pad */
573 if (!gst_object_set_parent (GST_OBJECT_CAST (internal),
574 GST_OBJECT_CAST (pad)))
577 /* The ghostpad is the parent of the internal pad and is the only object that
578 * can have a refcount on the internal pad.
579 * At this point, the GstGhostPad has a refcount of 1, and the internal pad has
581 * When the refcount of the GstGhostPad drops to 0, the ghostpad will dispose
582 * its refcount on the internal pad in the dispose method by un-parenting it.
583 * This is why we don't take extra refcounts in the assignments below
585 GST_PROXY_PAD_INTERNAL (pad) = internal;
586 GST_PROXY_PAD_INTERNAL (internal) = pad;
588 /* special activation functions for the internal pad */
589 gst_pad_set_activatemode_function (internal,
590 gst_ghost_pad_internal_activate_mode_default);
592 GST_OBJECT_UNLOCK (pad);
594 GST_GHOST_PAD_PRIVATE (gpad)->constructed = TRUE;
600 GST_WARNING_OBJECT (gpad, "Could not set internal pad %s:%s",
601 GST_DEBUG_PAD_NAME (internal));
602 g_critical ("Could not set internal pad %s:%s",
603 GST_DEBUG_PAD_NAME (internal));
604 GST_OBJECT_UNLOCK (pad);
605 gst_object_unref (internal);
611 gst_ghost_pad_new_full (const gchar * name, GstPadDirection dir,
612 GstPadTemplate * templ)
616 g_return_val_if_fail (dir != GST_PAD_UNKNOWN, NULL);
618 /* OBJECT CREATION */
620 ret = g_object_new (GST_TYPE_GHOST_PAD, "name", name,
621 "direction", dir, "template", templ, NULL);
623 ret = g_object_new (GST_TYPE_GHOST_PAD, "name", name,
624 "direction", dir, NULL);
627 if (!gst_ghost_pad_construct (ret))
628 goto construct_failed;
630 return GST_PAD_CAST (ret);
634 gst_object_unref (ret);
639 * gst_ghost_pad_new_no_target:
640 * @name: (allow-none): the name of the new pad, or %NULL to assign a default name.
641 * @dir: the direction of the ghostpad
643 * Create a new ghostpad without a target with the given direction.
644 * A target can be set on the ghostpad later with the
645 * gst_ghost_pad_set_target() function.
647 * The created ghostpad will not have a padtemplate.
649 * Returns: (transfer full) (nullable): a new #GstPad, or %NULL in
653 gst_ghost_pad_new_no_target (const gchar * name, GstPadDirection dir)
657 g_return_val_if_fail (dir != GST_PAD_UNKNOWN, NULL);
659 GST_LOG ("name:%s, direction:%d", GST_STR_NULL (name), dir);
661 ret = gst_ghost_pad_new_full (name, dir, NULL);
668 * @name: (allow-none): the name of the new pad, or %NULL to assign a default name
669 * @target: (transfer none): the pad to ghost.
671 * Create a new ghostpad with @target as the target. The direction will be taken
672 * from the target pad. @target must be unlinked.
674 * Will ref the target.
676 * Returns: (transfer floating) (nullable): a new #GstPad, or %NULL in
680 gst_ghost_pad_new (const gchar * name, GstPad * target)
684 g_return_val_if_fail (GST_IS_PAD (target), NULL);
685 g_return_val_if_fail (!gst_pad_is_linked (target), NULL);
687 GST_LOG ("name:%s, target:%s:%s", GST_STR_NULL (name),
688 GST_DEBUG_PAD_NAME (target));
690 if ((ret = gst_ghost_pad_new_no_target (name, GST_PAD_DIRECTION (target))))
691 if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (ret), target))
692 goto set_target_failed;
699 GST_WARNING_OBJECT (ret, "failed to set target %s:%s",
700 GST_DEBUG_PAD_NAME (target));
701 gst_object_unref (ret);
707 * gst_ghost_pad_new_from_template:
708 * @name: (allow-none): the name of the new pad, or %NULL to assign a default name.
709 * @target: (transfer none): the pad to ghost.
710 * @templ: (transfer none): the #GstPadTemplate to use on the ghostpad.
712 * Create a new ghostpad with @target as the target. The direction will be taken
713 * from the target pad. The template used on the ghostpad will be @template.
715 * Will ref the target.
717 * Returns: (transfer full) (nullable): a new #GstPad, or %NULL in
722 gst_ghost_pad_new_from_template (const gchar * name, GstPad * target,
723 GstPadTemplate * templ)
727 g_return_val_if_fail (GST_IS_PAD (target), NULL);
728 g_return_val_if_fail (!gst_pad_is_linked (target), NULL);
729 g_return_val_if_fail (templ != NULL, NULL);
730 g_return_val_if_fail (GST_PAD_TEMPLATE_DIRECTION (templ) ==
731 GST_PAD_DIRECTION (target), NULL);
733 GST_LOG ("name:%s, target:%s:%s, templ:%p", GST_STR_NULL (name),
734 GST_DEBUG_PAD_NAME (target), templ);
736 if ((ret = gst_ghost_pad_new_full (name, GST_PAD_DIRECTION (target), templ)))
737 if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (ret), target))
738 goto set_target_failed;
745 GST_WARNING_OBJECT (ret, "failed to set target %s:%s",
746 GST_DEBUG_PAD_NAME (target));
747 gst_object_unref (ret);
753 * gst_ghost_pad_new_no_target_from_template:
754 * @name: (allow-none): the name of the new pad, or %NULL to assign a default name
755 * @templ: (transfer none): the #GstPadTemplate to create the ghostpad from.
757 * Create a new ghostpad based on @templ, without setting a target. The
758 * direction will be taken from the @templ.
760 * Returns: (transfer full) (nullable): a new #GstPad, or %NULL in
764 gst_ghost_pad_new_no_target_from_template (const gchar * name,
765 GstPadTemplate * templ)
769 g_return_val_if_fail (templ != NULL, NULL);
772 gst_ghost_pad_new_full (name, GST_PAD_TEMPLATE_DIRECTION (templ), templ);
778 * gst_ghost_pad_get_target:
779 * @gpad: the #GstGhostPad
781 * Get the target pad of @gpad. Unref target pad after usage.
783 * Returns: (transfer full) (nullable): the target #GstPad, can be
784 * %NULL if the ghostpad has no target set. Unref target pad after
788 gst_ghost_pad_get_target (GstGhostPad * gpad)
792 g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), NULL);
794 ret = gst_proxy_pad_get_target (GST_PAD_CAST (gpad));
796 GST_DEBUG_OBJECT (gpad, "get target %s:%s", GST_DEBUG_PAD_NAME (ret));
802 * gst_ghost_pad_set_target:
803 * @gpad: the #GstGhostPad
804 * @newtarget: (transfer none) (allow-none): the new pad target
806 * Set the new target of the ghostpad @gpad. Any existing target
807 * is unlinked and links to the new target are established. if @newtarget is
808 * %NULL the target will be cleared.
810 * Returns: (transfer full): %TRUE if the new target could be set. This function
811 * can return %FALSE when the internal pads could not be linked.
814 gst_ghost_pad_set_target (GstGhostPad * gpad, GstPad * newtarget)
818 GstPadLinkReturn lret;
820 g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);
821 g_return_val_if_fail (GST_PAD_CAST (gpad) != newtarget, FALSE);
822 g_return_val_if_fail (newtarget != GST_PROXY_PAD_INTERNAL (gpad), FALSE);
824 GST_OBJECT_LOCK (gpad);
825 internal = GST_PROXY_PAD_INTERNAL (gpad);
828 GST_DEBUG_OBJECT (gpad, "set target %s:%s", GST_DEBUG_PAD_NAME (newtarget));
830 GST_DEBUG_OBJECT (gpad, "clearing target");
832 /* clear old target */
833 if ((oldtarget = gst_pad_get_peer (internal))) {
834 GST_OBJECT_UNLOCK (gpad);
836 /* unlink internal pad */
837 if (GST_PAD_IS_SRC (internal))
838 gst_pad_unlink (internal, oldtarget);
840 gst_pad_unlink (oldtarget, internal);
842 gst_object_unref (oldtarget);
844 GST_OBJECT_UNLOCK (gpad);
848 /* and link to internal pad without any checks */
849 GST_DEBUG_OBJECT (gpad, "connecting internal pad to target %"
850 GST_PTR_FORMAT, newtarget);
852 if (GST_PAD_IS_SRC (internal))
854 gst_pad_link_full (internal, newtarget, GST_PAD_LINK_CHECK_NOTHING);
857 gst_pad_link_full (newtarget, internal, GST_PAD_LINK_CHECK_NOTHING);
859 if (lret != GST_PAD_LINK_OK)
868 GST_WARNING_OBJECT (gpad, "could not link internal and target, reason:%s",
869 gst_pad_link_get_name (lret));