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., 59 Temple Place - Suite 330,
22 * Boston, MA 02111-1307, 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.
44 * Last reviewed on 2005-11-18 (0.9.5)
47 #include "gst_private.h"
50 #include "gstghostpad.h"
53 #define GST_CAT_DEFAULT GST_CAT_PADS
55 #define GST_PROXY_PAD_CAST(obj) ((GstProxyPad *)obj)
56 #define GST_PROXY_PAD_PRIVATE(obj) (GST_PROXY_PAD_CAST (obj)->priv)
57 #define GST_PROXY_PAD_TARGET(pad) (GST_PAD_PEER (GST_PROXY_PAD_INTERNAL (pad)))
58 #define GST_PROXY_PAD_INTERNAL(pad) (GST_PROXY_PAD_PRIVATE (pad)->internal)
60 struct _GstProxyPadPrivate
65 G_DEFINE_TYPE (GstProxyPad, gst_proxy_pad, GST_TYPE_PAD);
67 static GstPad *gst_proxy_pad_get_target (GstPad * pad);
70 * gst_proxy_pad_event_default:
71 * @pad: a #GstPad to push the event to.
72 * @parent: the parent of @pad or NULL
73 * @event: (transfer full): the #GstEvent to send to the pad.
75 * Invoke the default event of the proxy pad.
77 * Returns: TRUE if the event was handled.
82 gst_proxy_pad_event_default (GstPad * pad, GstObject * parent, GstEvent * event)
87 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
88 g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
90 internal = GST_PROXY_PAD_INTERNAL (pad);
91 res = gst_pad_push_event (internal, event);
97 gst_proxy_pad_query_caps (GstPad * pad, GstQuery * query)
102 GstPadTemplate *templ;
104 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
106 templ = GST_PAD_PAD_TEMPLATE (pad);
107 target = gst_proxy_pad_get_target (pad);
109 /* if we have a real target, proxy the call */
110 res = gst_pad_query (target, query);
112 GST_DEBUG_OBJECT (pad, "get caps of target %s:%s : %" GST_PTR_FORMAT,
113 GST_DEBUG_PAD_NAME (target), query);
115 gst_object_unref (target);
117 /* filter against the template */
121 filt = GST_PAD_TEMPLATE_CAPS (templ);
123 gst_query_parse_caps_result (query, &result);
124 tmp = gst_caps_intersect_full (result, filt, GST_CAPS_INTERSECT_FIRST);
125 gst_query_set_caps_result (query, tmp);
126 GST_DEBUG_OBJECT (pad,
127 "filtered against template gives %" GST_PTR_FORMAT, tmp);
128 gst_caps_unref (tmp);
136 gst_query_parse_caps (query, &filter);
138 /* else, if we have a template, use its caps. */
140 result = GST_PAD_TEMPLATE_CAPS (templ);
141 GST_DEBUG_OBJECT (pad,
142 "using pad template %p with caps %p %" GST_PTR_FORMAT, templ, result,
146 GstCaps *intersection;
148 GST_DEBUG_OBJECT (pad, "intersect with filter");
150 gst_caps_intersect_full (filter, result, GST_CAPS_INTERSECT_FIRST);
151 gst_query_set_caps_result (query, intersection);
152 gst_caps_unref (intersection);
154 gst_query_set_caps_result (query, result);
159 /* If there's a filter, return that */
160 if (filter != NULL) {
161 GST_DEBUG_OBJECT (pad, "return filter");
162 gst_query_set_caps_result (query, filter);
166 /* last resort, any caps */
167 GST_DEBUG_OBJECT (pad, "pad has no template, returning ANY");
168 result = gst_caps_new_any ();
169 gst_query_set_caps_result (query, result);
170 gst_caps_unref (result);
178 * gst_proxy_pad_query_default:
179 * @pad: a #GstPad to invoke the default query on.
180 * @parent: the parent of @pad or NULL
181 * @query: (transfer none): the #GstQuery to perform.
183 * Invoke the default query function of the proxy pad.
185 * Returns: TRUE if the query could be performed.
190 gst_proxy_pad_query_default (GstPad * pad, GstObject * parent, GstQuery * query)
195 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
196 g_return_val_if_fail (GST_IS_QUERY (query), FALSE);
199 switch (GST_QUERY_TYPE (query)) {
200 case GST_QUERY_ACCEPT_CAPS:
202 target = gst_proxy_pad_get_target (pad);
204 res = gst_pad_query (target, query);
205 gst_object_unref (target);
207 GST_DEBUG_OBJECT (pad, "no target");
208 /* We don't have a target, we return TRUE and we assume that any future
209 * target will be able to deal with any configured caps. */
216 res = gst_proxy_pad_query_caps (pad, query);
221 target = gst_proxy_pad_get_target (pad);
223 res = gst_pad_query (target, query);
224 gst_object_unref (target);
226 GST_DEBUG_OBJECT (pad, "no target pad");
236 * gst_proyx_pad_iterate_internal_links_default:
237 * @pad: the #GstPad to get the internal links of.
238 * @parent: the parent of @pad or NULL
240 * Invoke the default iterate internal links function of the proxy pad.
242 * Returns: a #GstIterator of #GstPad, or NULL if @pad has no parent. Unref each
243 * returned pad with gst_object_unref().
248 gst_proxy_pad_iterate_internal_links_default (GstPad * pad, GstObject * parent)
250 GstIterator *res = NULL;
254 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), NULL);
256 internal = GST_PROXY_PAD_INTERNAL (pad);
257 g_value_init (&v, GST_TYPE_PAD);
258 g_value_set_object (&v, internal);
259 res = gst_iterator_new_single (GST_TYPE_PAD, &v);
266 * gst_proxy_pad_chain_default:
267 * @pad: a sink #GstPad, returns GST_FLOW_ERROR if not.
268 * @parent: the parent of @pad or NULL
269 * @buffer: (transfer full): the #GstBuffer to send, return GST_FLOW_ERROR
272 * Invoke the default chain function of the proxy pad.
274 * Returns: a #GstFlowReturn from the pad.
279 gst_proxy_pad_chain_default (GstPad * pad, GstObject * parent,
285 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
286 g_return_val_if_fail (GST_IS_BUFFER (buffer), GST_FLOW_ERROR);
288 internal = GST_PROXY_PAD_INTERNAL (pad);
289 res = gst_pad_push (internal, buffer);
295 * gst_proxy_pad_chain_list_default:
296 * @pad: a sink #GstPad, returns GST_FLOW_ERROR if not.
297 * @parent: the parent of @pad or NULL
298 * @list: (transfer full): the #GstBufferList to send, return GST_FLOW_ERROR
301 * Invoke the default chain list function of the proxy pad.
303 * Returns: a #GstFlowReturn from the pad.
308 gst_proxy_pad_chain_list_default (GstPad * pad, GstObject * parent,
309 GstBufferList * list)
314 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
315 g_return_val_if_fail (GST_IS_BUFFER_LIST (list), GST_FLOW_ERROR);
317 internal = GST_PROXY_PAD_INTERNAL (pad);
318 res = gst_pad_push_list (internal, list);
324 * gst_proxy_pad_get_range_default:
325 * @pad: a src #GstPad, returns #GST_FLOW_ERROR if not.
326 * @offset: The start offset of the buffer
327 * @size: The length of the buffer
328 * @buffer: (out callee-allocates): a pointer to hold the #GstBuffer,
329 * returns #GST_FLOW_ERROR if %NULL.
331 * Invoke the default getrange function of the proxy pad.
333 * Returns: a #GstFlowReturn from the pad.
338 gst_proxy_pad_getrange_default (GstPad * pad, GstObject * parent,
339 guint64 offset, guint size, GstBuffer ** buffer)
344 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
345 g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
347 internal = GST_PROXY_PAD_INTERNAL (pad);
348 res = gst_pad_pull_range (internal, offset, size, buffer);
354 gst_proxy_pad_get_target (GstPad * pad)
358 GST_OBJECT_LOCK (pad);
359 target = GST_PROXY_PAD_TARGET (pad);
361 gst_object_ref (target);
362 GST_OBJECT_UNLOCK (pad);
368 * gst_proxy_pad_get_internal:
369 * @pad: the #GstProxyPad
371 * Get the internal pad of @pad. Unref target pad after usage.
373 * The internal pad of a #GstGhostPad is the internally used
374 * pad of opposite direction, which is used to link to the target.
376 * Returns: (transfer full): the target #GstProxyPad, can be NULL.
377 * Unref target pad after usage.
382 gst_proxy_pad_get_internal (GstProxyPad * pad)
386 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), NULL);
388 GST_OBJECT_LOCK (pad);
389 internal = GST_PROXY_PAD_INTERNAL (pad);
391 gst_object_ref (internal);
392 GST_OBJECT_UNLOCK (pad);
394 return GST_PROXY_PAD_CAST (internal);
398 * gst_proxy_pad_unlink_default:
399 * @pad: a #GstPad to unlink
401 * Invoke the default unlink function of the proxy pad.
406 gst_proxy_pad_unlink_default (GstPad * pad)
408 /* nothing to do anymore */
409 GST_DEBUG_OBJECT (pad, "pad is unlinked");
413 gst_proxy_pad_class_init (GstProxyPadClass * klass)
415 g_type_class_add_private (klass, sizeof (GstProxyPadPrivate));
417 /* Register common function pointer descriptions */
418 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_event_default);
419 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_query_default);
420 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_iterate_internal_links_default);
421 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_unlink_default);
422 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_chain_default);
423 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_chain_list_default);
424 GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_getrange_default);
428 gst_proxy_pad_init (GstProxyPad * ppad)
430 GstPad *pad = (GstPad *) ppad;
432 GST_PROXY_PAD_PRIVATE (ppad) = G_TYPE_INSTANCE_GET_PRIVATE (ppad,
433 GST_TYPE_PROXY_PAD, GstProxyPadPrivate);
435 gst_pad_set_event_function (pad, gst_proxy_pad_event_default);
436 gst_pad_set_query_function (pad, gst_proxy_pad_query_default);
437 gst_pad_set_iterate_internal_links_function (pad,
438 gst_proxy_pad_iterate_internal_links_default);
440 gst_pad_set_unlink_function (pad, gst_proxy_pad_unlink_default);
444 /***********************************************************************
445 * Ghost pads, implemented as a pair of proxy pads (sort of)
449 #define GST_GHOST_PAD_PRIVATE(obj) (GST_GHOST_PAD_CAST (obj)->priv)
451 struct _GstGhostPadPrivate
453 /* with PROXY_LOCK */
454 gboolean constructed;
457 G_DEFINE_TYPE (GstGhostPad, gst_ghost_pad, GST_TYPE_PROXY_PAD);
459 static void gst_ghost_pad_dispose (GObject * object);
462 * gst_ghost_pad_internal_activate_push_default:
463 * @pad: the #GstPad to activate or deactivate.
464 * @active: whether the pad should be active or not.
466 * Invoke the default activate push function of a proxy pad that is
467 * owned by a ghost pad.
469 * Returns: %TRUE if the operation was successful.
474 gst_ghost_pad_internal_activate_push_default (GstPad * pad, gboolean active)
479 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
481 GST_LOG_OBJECT (pad, "%sactivate push on %s:%s, we're ok",
482 (active ? "" : "de"), GST_DEBUG_PAD_NAME (pad));
484 /* in both cases (SRC and SINK) we activate just the internal pad. The targets
485 * will be activated later (or already in case of a ghost sinkpad). */
486 other = GST_PROXY_PAD_INTERNAL (pad);
487 ret = gst_pad_activate_push (other, active);
493 * gst_ghost_pad_internal_activate_pull_default:
494 * @pad: the #GstPad to activate or deactivate.
495 * @active: whether the pad should be active or not.
497 * Invoke the default activate pull function of a proxy pad that is
498 * owned by a ghost pad.
500 * Returns: %TRUE if the operation was successful.
505 gst_ghost_pad_internal_activate_pull_default (GstPad * pad, gboolean active)
510 g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
512 GST_LOG_OBJECT (pad, "%sactivate pull on %s:%s", (active ? "" : "de"),
513 GST_DEBUG_PAD_NAME (pad));
515 if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
516 /* we are activated in pull mode by our peer element, which is a sinkpad
517 * that wants to operate in pull mode. This activation has to propagate
518 * upstream through the pipeline. We call the internal activation function,
519 * which will trigger gst_ghost_pad_activate_pull_default, which propagates even
520 * further upstream */
521 GST_LOG_OBJECT (pad, "pad is src, activate internal");
522 other = GST_PROXY_PAD_INTERNAL (pad);
523 ret = gst_pad_activate_pull (other, active);
524 } else if (G_LIKELY ((other = gst_pad_get_peer (pad)))) {
525 /* We are SINK, the ghostpad is SRC, we propagate the activation upstream
526 * since we hold a pointer to the upstream peer. */
527 GST_LOG_OBJECT (pad, "activating peer");
528 ret = gst_pad_activate_pull (other, active);
529 gst_object_unref (other);
531 /* this is failure, we can't activate pull if there is no peer */
532 GST_LOG_OBJECT (pad, "not src and no peer, failing");
540 * gst_ghost_pad_activate_push_default:
541 * @pad: the #GstPad to activate or deactivate.
542 * @active: whether the pad should be active or not.
544 * Invoke the default activate push function of a ghost pad.
546 * Returns: %TRUE if the operation was successful.
551 gst_ghost_pad_activate_push_default (GstPad * pad, gboolean active)
556 g_return_val_if_fail (GST_IS_GHOST_PAD (pad), FALSE);
558 GST_LOG_OBJECT (pad, "%sactivate push on %s:%s, proxy internal",
559 (active ? "" : "de"), GST_DEBUG_PAD_NAME (pad));
561 /* just activate the internal pad */
562 other = GST_PROXY_PAD_INTERNAL (pad);
563 ret = gst_pad_activate_push (other, active);
569 * gst_ghost_pad_activate_pull_default:
570 * @pad: the #GstPad to activate or deactivate.
571 * @active: whether the pad should be active or not.
573 * Invoke the default activate pull function of a ghost pad.
575 * Returns: %TRUE if the operation was successful.
580 gst_ghost_pad_activate_pull_default (GstPad * pad, gboolean active)
585 g_return_val_if_fail (GST_IS_GHOST_PAD (pad), FALSE);
587 GST_LOG_OBJECT (pad, "%sactivate pull on %s:%s", (active ? "" : "de"),
588 GST_DEBUG_PAD_NAME (pad));
590 if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
591 /* the ghostpad is SRC and activated in pull mode by its peer, call the
592 * activation function of the internal pad to propagate the activation
594 GST_LOG_OBJECT (pad, "pad is src, activate internal");
595 other = GST_PROXY_PAD_INTERNAL (pad);
596 ret = gst_pad_activate_pull (other, active);
597 } else if (G_LIKELY ((other = gst_pad_get_peer (pad)))) {
598 /* We are SINK and activated by the internal pad, propagate activation
599 * upstream because we hold a ref to the upstream peer */
600 GST_LOG_OBJECT (pad, "activating peer");
601 ret = gst_pad_activate_pull (other, active);
602 gst_object_unref (other);
604 /* no peer, we fail */
605 GST_LOG_OBJECT (pad, "pad not src and no peer, failing");
613 * gst_ghost_pad_link_default:
614 * @pad: the #GstPad to link.
615 * @peer: the #GstPad peer
617 * Invoke the default link function of a ghost pad.
619 * Returns: #GstPadLinkReturn of the operation
624 gst_ghost_pad_link_default (GstPad * pad, GstPad * peer)
626 GstPadLinkReturn ret;
628 g_return_val_if_fail (GST_IS_GHOST_PAD (pad), GST_PAD_LINK_REFUSED);
629 g_return_val_if_fail (GST_IS_PAD (peer), GST_PAD_LINK_REFUSED);
631 GST_DEBUG_OBJECT (pad, "linking ghostpad");
633 ret = GST_PAD_LINK_OK;
634 /* if we are a source pad, we should call the peer link function
635 * if the peer has one, see design docs. */
636 if (GST_PAD_IS_SRC (pad)) {
637 if (GST_PAD_LINKFUNC (peer)) {
638 ret = GST_PAD_LINKFUNC (peer) (peer, pad);
639 if (ret != GST_PAD_LINK_OK)
640 GST_DEBUG_OBJECT (pad, "linking failed");
647 * gst_ghost_pad_unlink_default:
648 * @pad: the #GstPad to link.
650 * Invoke the default unlink function of a ghost pad.
655 gst_ghost_pad_unlink_default (GstPad * pad)
657 g_return_if_fail (GST_IS_GHOST_PAD (pad));
659 GST_DEBUG_OBJECT (pad, "unlinking ghostpad");
663 gst_ghost_pad_class_init (GstGhostPadClass * klass)
665 GObjectClass *gobject_class = (GObjectClass *) klass;
667 g_type_class_add_private (klass, sizeof (GstGhostPadPrivate));
669 gobject_class->dispose = gst_ghost_pad_dispose;
671 GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_activate_pull_default);
672 GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_activate_push_default);
673 GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_link_default);
677 gst_ghost_pad_init (GstGhostPad * pad)
679 GST_GHOST_PAD_PRIVATE (pad) = G_TYPE_INSTANCE_GET_PRIVATE (pad,
680 GST_TYPE_GHOST_PAD, GstGhostPadPrivate);
682 gst_pad_set_activatepull_function (GST_PAD_CAST (pad),
683 gst_ghost_pad_activate_pull_default);
684 gst_pad_set_activatepush_function (GST_PAD_CAST (pad),
685 gst_ghost_pad_activate_push_default);
689 gst_ghost_pad_dispose (GObject * object)
695 pad = GST_PAD (object);
697 GST_DEBUG_OBJECT (pad, "dispose");
699 gst_ghost_pad_set_target (GST_GHOST_PAD (pad), NULL);
701 /* Unlink here so that gst_pad_dispose doesn't. That would lead to a call to
702 * gst_ghost_pad_unlink_default when the ghost pad is in an inconsistent state */
703 peer = gst_pad_get_peer (pad);
705 if (GST_PAD_IS_SRC (pad))
706 gst_pad_unlink (pad, peer);
708 gst_pad_unlink (peer, pad);
710 gst_object_unref (peer);
713 GST_OBJECT_LOCK (pad);
714 internal = GST_PROXY_PAD_INTERNAL (pad);
716 gst_pad_set_activatepull_function (internal, NULL);
717 gst_pad_set_activatepush_function (internal, NULL);
719 /* disposes of the internal pad, since the ghostpad is the only possible object
720 * that has a refcount on the internal pad. */
721 gst_object_unparent (GST_OBJECT_CAST (internal));
722 GST_PROXY_PAD_INTERNAL (pad) = NULL;
724 GST_OBJECT_UNLOCK (pad);
726 G_OBJECT_CLASS (gst_ghost_pad_parent_class)->dispose (object);
730 * gst_ghost_pad_construct:
731 * @gpad: the newly allocated ghost pad
733 * Finish initialization of a newly allocated ghost pad.
735 * This function is most useful in language bindings and when subclassing
736 * #GstGhostPad; plugin and application developers normally will not call this
737 * function. Call this function directly after a call to g_object_new
738 * (GST_TYPE_GHOST_PAD, "direction", @dir, ..., NULL).
740 * Returns: %TRUE if the construction succeeds, %FALSE otherwise.
745 gst_ghost_pad_construct (GstGhostPad * gpad)
747 GstPadDirection dir, otherdir;
748 GstPadTemplate *templ;
749 GstPad *pad, *internal;
751 g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);
752 g_return_val_if_fail (GST_GHOST_PAD_PRIVATE (gpad)->constructed == FALSE,
755 g_object_get (gpad, "direction", &dir, "template", &templ, NULL);
757 g_return_val_if_fail (dir != GST_PAD_UNKNOWN, FALSE);
759 pad = GST_PAD (gpad);
761 /* Set directional padfunctions for ghostpad */
762 if (dir == GST_PAD_SINK) {
763 gst_pad_set_chain_function (pad, gst_proxy_pad_chain_default);
764 gst_pad_set_chain_list_function (pad, gst_proxy_pad_chain_list_default);
766 gst_pad_set_getrange_function (pad, gst_proxy_pad_getrange_default);
769 /* link/unlink functions */
770 gst_pad_set_link_function (pad, gst_ghost_pad_link_default);
771 gst_pad_set_unlink_function (pad, gst_ghost_pad_unlink_default);
773 /* INTERNAL PAD, it always exists and is child of the ghostpad */
774 otherdir = (dir == GST_PAD_SRC) ? GST_PAD_SINK : GST_PAD_SRC;
777 g_object_new (GST_TYPE_PROXY_PAD, "name", NULL,
778 "direction", otherdir, "template", templ, NULL);
779 /* release ref obtained via g_object_get */
780 gst_object_unref (templ);
783 g_object_new (GST_TYPE_PROXY_PAD, "name", NULL,
784 "direction", otherdir, NULL);
786 GST_PAD_UNSET_FLUSHING (internal);
788 /* Set directional padfunctions for internal pad */
789 if (dir == GST_PAD_SRC) {
790 gst_pad_set_chain_function (internal, gst_proxy_pad_chain_default);
791 gst_pad_set_chain_list_function (internal,
792 gst_proxy_pad_chain_list_default);
794 gst_pad_set_getrange_function (internal, gst_proxy_pad_getrange_default);
797 GST_OBJECT_LOCK (pad);
799 /* now make the ghostpad a parent of the internal pad */
800 if (!gst_object_set_parent (GST_OBJECT_CAST (internal),
801 GST_OBJECT_CAST (pad)))
804 /* The ghostpad is the parent of the internal pad and is the only object that
805 * can have a refcount on the internal pad.
806 * At this point, the GstGhostPad has a refcount of 1, and the internal pad has
808 * When the refcount of the GstGhostPad drops to 0, the ghostpad will dispose
809 * its refcount on the internal pad in the dispose method by un-parenting it.
810 * This is why we don't take extra refcounts in the assignments below
812 GST_PROXY_PAD_INTERNAL (pad) = internal;
813 GST_PROXY_PAD_INTERNAL (internal) = pad;
815 /* special activation functions for the internal pad */
816 gst_pad_set_activatepull_function (internal,
817 gst_ghost_pad_internal_activate_pull_default);
818 gst_pad_set_activatepush_function (internal,
819 gst_ghost_pad_internal_activate_push_default);
821 GST_OBJECT_UNLOCK (pad);
823 GST_GHOST_PAD_PRIVATE (gpad)->constructed = TRUE;
829 GST_WARNING_OBJECT (gpad, "Could not set internal pad %s:%s",
830 GST_DEBUG_PAD_NAME (internal));
831 g_critical ("Could not set internal pad %s:%s",
832 GST_DEBUG_PAD_NAME (internal));
833 GST_OBJECT_UNLOCK (pad);
834 gst_object_unref (internal);
840 gst_ghost_pad_new_full (const gchar * name, GstPadDirection dir,
841 GstPadTemplate * templ)
845 g_return_val_if_fail (dir != GST_PAD_UNKNOWN, NULL);
847 /* OBJECT CREATION */
849 ret = g_object_new (GST_TYPE_GHOST_PAD, "name", name,
850 "direction", dir, "template", templ, NULL);
852 ret = g_object_new (GST_TYPE_GHOST_PAD, "name", name,
853 "direction", dir, NULL);
856 if (!gst_ghost_pad_construct (ret))
857 goto construct_failed;
859 return GST_PAD_CAST (ret);
863 gst_object_unref (ret);
868 * gst_ghost_pad_new_no_target:
869 * @name: (allow-none): the name of the new pad, or NULL to assign a default name.
870 * @dir: the direction of the ghostpad
872 * Create a new ghostpad without a target with the given direction.
873 * A target can be set on the ghostpad later with the
874 * gst_ghost_pad_set_target() function.
876 * The created ghostpad will not have a padtemplate.
878 * Returns: (transfer full): a new #GstPad, or NULL in case of an error.
881 gst_ghost_pad_new_no_target (const gchar * name, GstPadDirection dir)
885 g_return_val_if_fail (dir != GST_PAD_UNKNOWN, NULL);
887 GST_LOG ("name:%s, direction:%d", GST_STR_NULL (name), dir);
889 ret = gst_ghost_pad_new_full (name, dir, NULL);
896 * @name: (allow-none): the name of the new pad, or NULL to assign a default name
897 * @target: (transfer none): the pad to ghost.
899 * Create a new ghostpad with @target as the target. The direction will be taken
900 * from the target pad. @target must be unlinked.
902 * Will ref the target.
904 * Returns: (transfer full): a new #GstPad, or NULL in case of an error.
907 gst_ghost_pad_new (const gchar * name, GstPad * target)
911 g_return_val_if_fail (GST_IS_PAD (target), NULL);
912 g_return_val_if_fail (!gst_pad_is_linked (target), NULL);
914 GST_LOG ("name:%s, target:%s:%s", GST_STR_NULL (name),
915 GST_DEBUG_PAD_NAME (target));
917 if ((ret = gst_ghost_pad_new_no_target (name, GST_PAD_DIRECTION (target))))
918 if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (ret), target))
919 goto set_target_failed;
926 GST_WARNING_OBJECT (ret, "failed to set target %s:%s",
927 GST_DEBUG_PAD_NAME (target));
928 gst_object_unref (ret);
934 * gst_ghost_pad_new_from_template:
935 * @name: (allow-none): the name of the new pad, or NULL to assign a default name.
936 * @target: (transfer none): the pad to ghost.
937 * @templ: (transfer none): the #GstPadTemplate to use on the ghostpad.
939 * Create a new ghostpad with @target as the target. The direction will be taken
940 * from the target pad. The template used on the ghostpad will be @template.
942 * Will ref the target.
944 * Returns: (transfer full): a new #GstPad, or NULL in case of an error.
950 gst_ghost_pad_new_from_template (const gchar * name, GstPad * target,
951 GstPadTemplate * templ)
955 g_return_val_if_fail (GST_IS_PAD (target), NULL);
956 g_return_val_if_fail (!gst_pad_is_linked (target), NULL);
957 g_return_val_if_fail (templ != NULL, NULL);
958 g_return_val_if_fail (GST_PAD_TEMPLATE_DIRECTION (templ) ==
959 GST_PAD_DIRECTION (target), NULL);
961 GST_LOG ("name:%s, target:%s:%s, templ:%p", GST_STR_NULL (name),
962 GST_DEBUG_PAD_NAME (target), templ);
964 if ((ret = gst_ghost_pad_new_full (name, GST_PAD_DIRECTION (target), templ)))
965 if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (ret), target))
966 goto set_target_failed;
973 GST_WARNING_OBJECT (ret, "failed to set target %s:%s",
974 GST_DEBUG_PAD_NAME (target));
975 gst_object_unref (ret);
981 * gst_ghost_pad_new_no_target_from_template:
982 * @name: (allow-none): the name of the new pad, or NULL to assign a default name
983 * @templ: (transfer none): the #GstPadTemplate to create the ghostpad from.
985 * Create a new ghostpad based on @templ, without setting a target. The
986 * direction will be taken from the @templ.
988 * Returns: (transfer full): a new #GstPad, or NULL in case of an error.
993 gst_ghost_pad_new_no_target_from_template (const gchar * name,
994 GstPadTemplate * templ)
998 g_return_val_if_fail (templ != NULL, NULL);
1001 gst_ghost_pad_new_full (name, GST_PAD_TEMPLATE_DIRECTION (templ), templ);
1007 * gst_ghost_pad_get_target:
1008 * @gpad: the #GstGhostPad
1010 * Get the target pad of @gpad. Unref target pad after usage.
1012 * Returns: (transfer full): the target #GstPad, can be NULL if the ghostpad
1013 * has no target set. Unref target pad after usage.
1016 gst_ghost_pad_get_target (GstGhostPad * gpad)
1020 g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), NULL);
1022 ret = gst_proxy_pad_get_target (GST_PAD_CAST (gpad));
1024 GST_DEBUG_OBJECT (gpad, "get target %s:%s", GST_DEBUG_PAD_NAME (ret));
1030 * gst_ghost_pad_set_target:
1031 * @gpad: the #GstGhostPad
1032 * @newtarget: (transfer none) (allow-none): the new pad target
1034 * Set the new target of the ghostpad @gpad. Any existing target
1035 * is unlinked and links to the new target are established. if @newtarget is
1036 * NULL the target will be cleared.
1038 * Returns: (transfer full): TRUE if the new target could be set. This function
1039 * can return FALSE when the internal pads could not be linked.
1042 gst_ghost_pad_set_target (GstGhostPad * gpad, GstPad * newtarget)
1046 GstPadLinkReturn lret;
1048 g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);
1049 g_return_val_if_fail (GST_PAD_CAST (gpad) != newtarget, FALSE);
1050 g_return_val_if_fail (newtarget != GST_PROXY_PAD_INTERNAL (gpad), FALSE);
1052 /* no need for locking, the internal pad's lifecycle is directly linked to the
1054 internal = GST_PROXY_PAD_INTERNAL (gpad);
1057 GST_DEBUG_OBJECT (gpad, "set target %s:%s", GST_DEBUG_PAD_NAME (newtarget));
1059 GST_DEBUG_OBJECT (gpad, "clearing target");
1061 /* clear old target */
1062 GST_OBJECT_LOCK (gpad);
1063 if ((oldtarget = GST_PROXY_PAD_TARGET (gpad))) {
1064 GST_OBJECT_UNLOCK (gpad);
1066 /* unlink internal pad */
1067 if (GST_PAD_IS_SRC (internal))
1068 gst_pad_unlink (internal, oldtarget);
1070 gst_pad_unlink (oldtarget, internal);
1072 GST_OBJECT_UNLOCK (gpad);
1076 /* and link to internal pad without any checks */
1077 GST_DEBUG_OBJECT (gpad, "connecting internal pad to target");
1079 if (GST_PAD_IS_SRC (internal))
1081 gst_pad_link_full (internal, newtarget, GST_PAD_LINK_CHECK_NOTHING);
1084 gst_pad_link_full (newtarget, internal, GST_PAD_LINK_CHECK_NOTHING);
1086 if (lret != GST_PAD_LINK_OK)
1095 GST_WARNING_OBJECT (gpad, "could not link internal and target, reason:%d",