gstreamer/gst/gstghostpad.c
Tim-Philipp Müller 696cf53af5 gst/gstghostpad.c: Don't ref NULL target pad (#322751). Improve docs.
Original commit message from CVS:
* gst/gstghostpad.c: (gst_proxy_pad_get_target):
Don't ref NULL target pad (#322751). Improve docs.
2005-11-29 13:10:38 +00:00

880 lines
21 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
* 2005 Andy Wingo <wingo@pobox.com>
*
* gstghostpad.c: Proxy pads
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstghostpad
* @short_description: Pseudo link pads
* @see_also: #GstPad
*
* GhostPads are useful when organizing pipelines with #GstBin like elements.
* The idea here is to create hierarchical element graphs. The bin element
* contains a sub-graph. Now one would like to treat the bin-element like other
* #GstElements. This is where GhostPads come into play. A GhostPad acts as a
* proxy for another pad. Thus the bin can have sink and source ghost-pads that
* are accociated with sink and source pads of the child elements.
*
* If the target pad is known at creation time, gst_ghost_pad_new() is the
* function to use to get a ghost-pad. Otherwise one can use gst_ghost_pad_new_no_target()
* to create the ghost-pad and use gst_ghost_pad_set_target() to establish the
* accociation later on.
*
* Last reviewed on 2005-11-18 (0.9.5)
*/
#include "gst_private.h"
#include "gstghostpad.h"
#define GST_TYPE_PROXY_PAD (gst_proxy_pad_get_type ())
#define GST_IS_PROXY_PAD(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_PROXY_PAD))
#define GST_IS_PROXY_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_PROXY_PAD))
#define GST_PROXY_PAD(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_PROXY_PAD, GstProxyPad))
#define GST_PROXY_PAD_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_PROXY_PAD, GstProxyPadClass))
#define GST_PROXY_PAD_TARGET(pad) (GST_PROXY_PAD (pad)->target)
typedef struct _GstProxyPad GstProxyPad;
typedef struct _GstProxyPadClass GstProxyPadClass;
#define GST_PROXY_GET_LOCK(pad) (GST_PROXY_PAD (pad)->proxy_lock)
#define GST_PROXY_LOCK(pad) (g_mutex_lock (GST_PROXY_GET_LOCK (pad)))
#define GST_PROXY_UNLOCK(pad) (g_mutex_unlock (GST_PROXY_GET_LOCK (pad)))
struct _GstProxyPad
{
GstPad pad;
/* with PROXY_LOCK */
GMutex *proxy_lock;
GstPad *target;
/*< private > */
gpointer _gst_reserved[1];
};
struct _GstProxyPadClass
{
GstPadClass parent_class;
/*< private > */
gpointer _gst_reserved[1];
};
G_DEFINE_TYPE (GstProxyPad, gst_proxy_pad, GST_TYPE_PAD);
static GstPad *gst_proxy_pad_get_target (GstPad * pad);
static void gst_proxy_pad_dispose (GObject * object);
static void gst_proxy_pad_finalize (GObject * object);
#ifndef GST_DISABLE_LOADSAVE
static xmlNodePtr gst_proxy_pad_save_thyself (GstObject * object,
xmlNodePtr parent);
#endif
static void
gst_proxy_pad_class_init (GstProxyPadClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_proxy_pad_dispose);
gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_proxy_pad_finalize);
#ifndef GST_DISABLE_LOADSAVE
{
GstObjectClass *gstobject_class = (GstObjectClass *) klass;
gstobject_class->save_thyself =
GST_DEBUG_FUNCPTR (gst_proxy_pad_save_thyself);
}
#endif
}
const GstQueryType *
gst_proxy_pad_do_query_type (GstPad * pad)
{
GstPad *target = gst_proxy_pad_get_target (pad);
const GstQueryType *res;
g_return_val_if_fail (target != NULL, NULL);
res = gst_pad_get_query_types (target);
gst_object_unref (target);
return res;
}
static gboolean
gst_proxy_pad_do_event (GstPad * pad, GstEvent * event)
{
gboolean res;
GstPad *target = gst_proxy_pad_get_target (pad);
g_return_val_if_fail (target != NULL, FALSE);
res = gst_pad_send_event (target, event);
gst_object_unref (target);
return res;
}
static gboolean
gst_proxy_pad_do_query (GstPad * pad, GstQuery * query)
{
gboolean res;
GstPad *target = gst_proxy_pad_get_target (pad);
g_return_val_if_fail (target != NULL, FALSE);
res = gst_pad_query (target, query);
gst_object_unref (target);
return res;
}
static GList *
gst_proxy_pad_do_internal_link (GstPad * pad)
{
GstPad *target = gst_proxy_pad_get_target (pad);
GList *res;
g_return_val_if_fail (target != NULL, NULL);
res = gst_pad_get_internal_links (target);
gst_object_unref (target);
return res;
}
static GstFlowReturn
gst_proxy_pad_do_bufferalloc (GstPad * pad, guint64 offset, guint size,
GstCaps * caps, GstBuffer ** buf)
{
GstFlowReturn result;
GstPad *target = gst_proxy_pad_get_target (pad);
GstPad *peer;
g_return_val_if_fail (target != NULL, GST_FLOW_NOT_LINKED);
peer = gst_pad_get_peer (target);
if (peer) {
GST_DEBUG ("buffer alloc on %s:%s", GST_DEBUG_PAD_NAME (target));
result = gst_pad_alloc_buffer (peer, offset, size, caps, buf);
gst_object_unref (peer);
} else {
result = GST_FLOW_NOT_LINKED;
}
gst_object_unref (target);
return result;
}
static GstFlowReturn
gst_proxy_pad_do_chain (GstPad * pad, GstBuffer * buffer)
{
GstPad *target = gst_proxy_pad_get_target (pad);
GstFlowReturn res;
g_return_val_if_fail (target != NULL, GST_FLOW_NOT_LINKED);
res = gst_pad_chain (target, buffer);
gst_object_unref (target);
return res;
}
static GstFlowReturn
gst_proxy_pad_do_getrange (GstPad * pad, guint64 offset, guint size,
GstBuffer ** buffer)
{
GstPad *target = gst_proxy_pad_get_target (pad);
GstFlowReturn res;
g_return_val_if_fail (target != NULL, GST_FLOW_NOT_LINKED);
res = gst_pad_get_range (target, offset, size, buffer);
gst_object_unref (target);
return res;
}
static gboolean
gst_proxy_pad_do_checkgetrange (GstPad * pad)
{
gboolean result;
GstPad *target = gst_proxy_pad_get_target (pad);
GstPad *peer;
g_return_val_if_fail (target != NULL, FALSE);
peer = gst_pad_get_peer (target);
if (peer) {
result = gst_pad_check_pull_range (peer);
gst_object_unref (peer);
} else {
result = FALSE;
}
gst_object_unref (target);
return result;
}
static GstCaps *
gst_proxy_pad_do_getcaps (GstPad * pad)
{
GstPad *target = gst_proxy_pad_get_target (pad);
GstCaps *res;
g_return_val_if_fail (target != NULL, NULL);
res = gst_pad_get_caps (target);
gst_object_unref (target);
return res;
}
static gboolean
gst_proxy_pad_do_acceptcaps (GstPad * pad, GstCaps * caps)
{
GstPad *target = gst_proxy_pad_get_target (pad);
gboolean res;
g_return_val_if_fail (target != NULL, FALSE);
res = gst_pad_accept_caps (target, caps);
gst_object_unref (target);
return res;
}
static void
gst_proxy_pad_do_fixatecaps (GstPad * pad, GstCaps * caps)
{
GstPad *target = gst_proxy_pad_get_target (pad);
g_return_if_fail (target != NULL);
gst_pad_fixate_caps (target, caps);
gst_object_unref (target);
}
static gboolean
gst_proxy_pad_do_setcaps (GstPad * pad, GstCaps * caps)
{
GstPad *target = gst_proxy_pad_get_target (pad);
gboolean res;
g_return_val_if_fail (target != NULL, FALSE);
res = gst_pad_set_caps (target, caps);
gst_object_unref (target);
return res;
}
#define SETFUNC(member, kind) \
if (target->member) \
gst_pad_set_##kind##_function (pad, gst_proxy_pad_do_##kind)
static gboolean
gst_proxy_pad_set_target_unlocked (GstPad * pad, GstPad * target)
{
GstPad *oldtarget;
GST_DEBUG ("set target %s:%s on %s:%s",
GST_DEBUG_PAD_NAME (target), GST_DEBUG_PAD_NAME (pad));
/* clear old target */
if ((oldtarget = GST_PROXY_PAD_TARGET (pad))) {
gst_object_unref (oldtarget);
GST_PROXY_PAD_TARGET (pad) = NULL;
}
if (target) {
/* set and ref new target if any */
GST_PROXY_PAD_TARGET (pad) = gst_object_ref (target);
/* really, all these should have default implementations so I can set them
* in the _init() instead of here */
SETFUNC (querytypefunc, query_type);
SETFUNC (eventfunc, event);
SETFUNC (queryfunc, query);
SETFUNC (intlinkfunc, internal_link);
SETFUNC (getcapsfunc, getcaps);
SETFUNC (acceptcapsfunc, acceptcaps);
SETFUNC (fixatecapsfunc, fixatecaps);
SETFUNC (setcapsfunc, setcaps);
if (GST_PAD_DIRECTION (pad) == GST_PAD_SINK) {
SETFUNC (bufferallocfunc, bufferalloc);
SETFUNC (chainfunc, chain);
} else {
SETFUNC (getrangefunc, getrange);
SETFUNC (checkgetrangefunc, checkgetrange);
}
}
return TRUE;
}
static gboolean
gst_proxy_pad_set_target (GstPad * pad, GstPad * target)
{
gboolean result;
GST_PROXY_LOCK (pad);
result = gst_proxy_pad_set_target_unlocked (pad, target);
GST_PROXY_UNLOCK (pad);
return result;
}
static GstPad *
gst_proxy_pad_get_target (GstPad * pad)
{
GstPad *target;
GST_PROXY_LOCK (pad);
target = GST_PROXY_PAD_TARGET (pad);
if (target)
gst_object_ref (target);
GST_PROXY_UNLOCK (pad);
return target;
}
static void
gst_proxy_pad_init (GstProxyPad * pad)
{
pad->proxy_lock = g_mutex_new ();
}
static void
gst_proxy_pad_dispose (GObject * object)
{
GstPad *pad = GST_PAD (object);
GST_PROXY_LOCK (pad);
gst_object_replace ((GstObject **) & GST_PROXY_PAD_TARGET (pad), NULL);
GST_PROXY_UNLOCK (pad);
G_OBJECT_CLASS (gst_proxy_pad_parent_class)->dispose (object);
}
static void
gst_proxy_pad_finalize (GObject * object)
{
GstProxyPad *pad = GST_PROXY_PAD (object);
g_mutex_free (pad->proxy_lock);
pad->proxy_lock = NULL;
G_OBJECT_CLASS (gst_proxy_pad_parent_class)->finalize (object);
}
#ifndef GST_DISABLE_LOADSAVE
/**
* gst_proxy_pad_save_thyself:
* @pad: a ghost #GstPad to save.
* @parent: the parent #xmlNodePtr to save the description in.
*
* Saves the ghost pad into an xml representation.
*
* Returns: the #xmlNodePtr representation of the pad.
*/
static xmlNodePtr
gst_proxy_pad_save_thyself (GstObject * object, xmlNodePtr parent)
{
xmlNodePtr self;
g_return_val_if_fail (GST_IS_PROXY_PAD (object), NULL);
self = xmlNewChild (parent, NULL, (xmlChar *) "ghostpad", NULL);
xmlNewChild (self, NULL, (xmlChar *) "name",
(xmlChar *) GST_OBJECT_NAME (object));
xmlNewChild (self, NULL, (xmlChar *) "parent",
(xmlChar *) GST_OBJECT_NAME (GST_OBJECT_PARENT (object)));
/* FIXME FIXME FIXME! */
return self;
}
#endif /* GST_DISABLE_LOADSAVE */
/***********************************************************************
* Ghost pads, implemented as a pair of proxy pads (sort of)
*/
struct _GstGhostPad
{
GstProxyPad pad;
/* with PROXY_LOCK */
GstPad *internal;
gulong notify_id;
/*< private > */
gpointer _gst_reserved[GST_PADDING];
};
struct _GstGhostPadClass
{
GstProxyPadClass parent_class;
/*< private > */
gpointer _gst_reserved[GST_PADDING];
};
G_DEFINE_TYPE (GstGhostPad, gst_ghost_pad, GST_TYPE_PROXY_PAD);
static gboolean gst_ghost_pad_set_internal (GstGhostPad * pad,
GstPad * internal);
static void gst_ghost_pad_dispose (GObject * object);
/* Work around g_logv's use of G_GNUC_PRINTF because gcc chokes on %P, which we
* use for GST_PTR_FORMAT. */
static void
gst_critical (const gchar * format, ...)
{
va_list args;
va_start (args, format);
g_logv (G_LOG_DOMAIN, G_LOG_LEVEL_CRITICAL, format, args);
va_end (args);
}
static GstPad *
gst_ghost_pad_get_internal (GstPad * pad)
{
GstPad *internal;
GST_PROXY_LOCK (pad);
internal = GST_GHOST_PAD (pad)->internal;
if (internal)
gst_object_ref (internal);
GST_PROXY_UNLOCK (pad);
return internal;
}
static void
gst_ghost_pad_class_init (GstGhostPadClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_ghost_pad_dispose);
}
/* see gstghostpad design docs */
static gboolean
gst_ghost_pad_internal_do_activate_push (GstPad * pad, gboolean active)
{
gboolean ret;
if (GST_PAD_DIRECTION (pad) == GST_PAD_SINK) {
GstPad *parent = GST_PAD (gst_object_get_parent (GST_OBJECT (pad)));
if (parent) {
g_return_val_if_fail (GST_IS_GHOST_PAD (parent), FALSE);
ret = gst_pad_activate_push (parent, active);
gst_object_unref (parent);
} else {
ret = FALSE;
}
} else {
GstPad *peer = gst_pad_get_peer (pad);
if (peer) {
ret = gst_pad_activate_push (peer, active);
gst_object_unref (peer);
} else {
ret = FALSE;
}
}
return ret;
}
static gboolean
gst_ghost_pad_internal_do_activate_pull (GstPad * pad, gboolean active)
{
gboolean ret;
if (GST_PAD_DIRECTION (pad) == GST_PAD_SINK) {
GstPad *peer = gst_pad_get_peer (pad);
if (peer) {
ret = gst_pad_activate_pull (peer, active);
gst_object_unref (peer);
} else {
ret = FALSE;
}
} else {
GstPad *parent = GST_PAD (gst_object_get_parent (GST_OBJECT (pad)));
if (parent) {
g_return_val_if_fail (GST_IS_GHOST_PAD (parent), FALSE);
ret = gst_pad_activate_pull (parent, active);
gst_object_unref (parent);
} else {
ret = FALSE;
}
}
return ret;
}
static gboolean
gst_ghost_pad_do_activate_push (GstPad * pad, gboolean active)
{
gboolean ret;
if (GST_PAD_DIRECTION (pad) == GST_PAD_SINK) {
GstPad *internal = gst_ghost_pad_get_internal (pad);
if (internal) {
ret = gst_pad_activate_push (internal, active);
gst_object_unref (internal);
} else {
ret = TRUE;
}
} else {
ret = TRUE;
}
return ret;
}
static gboolean
gst_ghost_pad_do_activate_pull (GstPad * pad, gboolean active)
{
gboolean ret;
if (GST_PAD_DIRECTION (pad) == GST_PAD_SINK) {
GstPad *peer = gst_pad_get_peer (pad);
if (peer) {
ret = gst_pad_activate_pull (peer, active);
gst_object_unref (peer);
} else {
ret = FALSE;
}
} else {
GstPad *internal = gst_ghost_pad_get_internal (pad);
if (internal) {
ret = gst_pad_activate_pull (internal, active);
gst_object_unref (internal);
} else {
ret = FALSE;
}
}
return ret;
}
static GstPadLinkReturn
gst_ghost_pad_do_link (GstPad * pad, GstPad * peer)
{
GstPad *internal, *target;
GstPadLinkReturn ret;
target = gst_proxy_pad_get_target (pad);
g_return_val_if_fail (target != NULL, GST_PAD_LINK_NOSCHED);
/* proxy the peer into the bin */
internal = g_object_new (GST_TYPE_PROXY_PAD,
"name", NULL,
"direction", GST_PAD_DIRECTION (peer),
"template", GST_PAD_PAD_TEMPLATE (peer), NULL);
gst_proxy_pad_set_target (internal, peer);
gst_ghost_pad_set_internal (GST_GHOST_PAD (pad), internal);
if (GST_PAD_IS_SRC (internal))
ret = gst_pad_link (internal, target);
else
ret = gst_pad_link (target, internal);
/* if we are a source pad, we should call the peer link function
* if the peer has one */
if (GST_PAD_IS_SRC (pad)) {
if (GST_PAD_LINKFUNC (peer) && ret == GST_PAD_LINK_OK)
ret = GST_PAD_LINKFUNC (peer) (peer, pad);
}
gst_object_unref (target);
if (ret == GST_PAD_LINK_OK)
gst_pad_set_active (internal, GST_PAD_ACTIVATE_MODE (pad));
else
gst_ghost_pad_set_internal (GST_GHOST_PAD (pad), NULL);
return ret;
}
static void
gst_ghost_pad_do_unlink (GstPad * pad)
{
GstPad *target = gst_proxy_pad_get_target (pad);
g_return_if_fail (target != NULL);
GST_DEBUG_OBJECT (pad, "unlinking ghostpad");
if (target->unlinkfunc)
target->unlinkfunc (target);
gst_ghost_pad_set_internal (GST_GHOST_PAD (pad), NULL);
gst_object_unref (target);
}
static void
on_int_notify (GstPad * internal, GParamSpec * unused, GstGhostPad * pad)
{
GstCaps *caps;
g_object_get (internal, "caps", &caps, NULL);
GST_OBJECT_LOCK (pad);
gst_caps_replace (&(GST_PAD_CAPS (pad)), caps);
GST_OBJECT_UNLOCK (pad);
g_object_notify (G_OBJECT (pad), "caps");
if (caps)
gst_caps_unref (caps);
}
static gboolean
gst_ghost_pad_set_internal (GstGhostPad * pad, GstPad * internal)
{
GST_PROXY_LOCK (pad);
/* first remove old internal pad */
if (pad->internal) {
GstPad *intpeer;
gst_pad_set_activatepull_function (pad->internal, NULL);
gst_pad_set_activatepush_function (pad->internal, NULL);
g_signal_handler_disconnect (pad->internal, pad->notify_id);
intpeer = gst_pad_get_peer (pad->internal);
if (intpeer) {
if (GST_PAD_IS_SRC (pad->internal))
gst_pad_unlink (pad->internal, intpeer);
else
gst_pad_unlink (intpeer, pad->internal);
gst_object_unref (intpeer);
}
/* should dispose it */
gst_object_unparent (GST_OBJECT_CAST (pad->internal));
}
/* then set new internal pad */
if (internal) {
if (!gst_object_set_parent (GST_OBJECT_CAST (internal),
GST_OBJECT_CAST (pad)))
goto could_not_set;
/* could be more general here, iterating over all writable properties...
* taking the short road for now tho */
pad->notify_id = g_signal_connect (internal, "notify::caps",
G_CALLBACK (on_int_notify), pad);
on_int_notify (internal, NULL, pad);
gst_pad_set_activatepull_function (GST_PAD (internal),
GST_DEBUG_FUNCPTR (gst_ghost_pad_internal_do_activate_pull));
gst_pad_set_activatepush_function (GST_PAD (internal),
GST_DEBUG_FUNCPTR (gst_ghost_pad_internal_do_activate_push));
/* a ref was taken by set_parent */
}
pad->internal = internal;
GST_PROXY_UNLOCK (pad);
return TRUE;
/* ERRORS */
could_not_set:
{
gst_critical ("Could not set internal pad %" GST_PTR_FORMAT, internal);
GST_PROXY_UNLOCK (pad);
return FALSE;
}
}
static void
gst_ghost_pad_init (GstGhostPad * pad)
{
gst_pad_set_activatepull_function (GST_PAD (pad),
GST_DEBUG_FUNCPTR (gst_ghost_pad_do_activate_pull));
gst_pad_set_activatepush_function (GST_PAD (pad),
GST_DEBUG_FUNCPTR (gst_ghost_pad_do_activate_push));
}
static void
gst_ghost_pad_dispose (GObject * object)
{
gst_ghost_pad_set_internal (GST_GHOST_PAD (object), NULL);
G_OBJECT_CLASS (gst_ghost_pad_parent_class)->dispose (object);
}
/**
* gst_ghost_pad_new_no_target:
* @name: the name of the new pad, or NULL to assign a default name.
* @dir: the direction of the ghostpad
*
* Create a new ghostpad without a target with the given direction.
* A target can be set on the ghostpad later with the
* gst_ghost_pad_set_target() function.
*
* The created ghostpad will not have a padtemplate.
*
* Returns: a new #GstPad, or NULL in case of an error.
*/
GstPad *
gst_ghost_pad_new_no_target (const gchar * name, GstPadDirection dir)
{
GstPad *ret;
ret = g_object_new (GST_TYPE_GHOST_PAD, "name", name, "direction", dir, NULL);
gst_pad_set_activatepush_function (ret,
GST_DEBUG_FUNCPTR (gst_ghost_pad_do_activate_push));
gst_pad_set_link_function (ret, GST_DEBUG_FUNCPTR (gst_ghost_pad_do_link));
gst_pad_set_unlink_function (ret,
GST_DEBUG_FUNCPTR (gst_ghost_pad_do_unlink));
return ret;
}
/**
* gst_ghost_pad_new:
* @name: the name of the new pad, or NULL to assign a default name.
* @target: the pad to ghost.
*
* Create a new ghostpad with @target as the target. The direction and
* padtemplate will be taken from the target pad.
*
* Will ref the target.
*
* Returns: a new #GstPad, or NULL in case of an error.
*/
GstPad *
gst_ghost_pad_new (const gchar * name, GstPad * target)
{
GstPad *ret;
g_return_val_if_fail (GST_IS_PAD (target), NULL);
g_return_val_if_fail (!gst_pad_is_linked (target), NULL);
if ((ret = gst_ghost_pad_new_no_target (name, GST_PAD_DIRECTION (target)))) {
g_object_set (G_OBJECT (ret),
"template", GST_PAD_PAD_TEMPLATE (target), NULL);
gst_ghost_pad_set_target (GST_GHOST_PAD (ret), target);
}
return ret;
}
/**
* gst_ghost_pad_get_target:
* @gpad: the #GstGhostpad
*
* Get the target pad of #gpad. Unref target pad after usage.
*
* Returns: the target #GstPad, can be NULL if the ghostpad
* has no target set. Unref target pad after usage.
*/
GstPad *
gst_ghost_pad_get_target (GstGhostPad * gpad)
{
g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), NULL);
return gst_proxy_pad_get_target (GST_PAD_CAST (gpad));
}
/**
* gst_ghost_pad_set_target:
* @gpad: the #GstGhostpad
* @newtarget: the new pad target
*
* Set the new target of the ghostpad @gpad. Any existing target
* is unlinked and links to the new target are established.
*
* Returns: TRUE if the new target could be set, FALSE otherwise.
*/
gboolean
gst_ghost_pad_set_target (GstGhostPad * gpad, GstPad * newtarget)
{
GstPad *internal;
GstPad *oldtarget;
gboolean result;
g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);
GST_PROXY_LOCK (gpad);
internal = gpad->internal;
GST_DEBUG ("set target %s:%s on %s:%s",
GST_DEBUG_PAD_NAME (newtarget), GST_DEBUG_PAD_NAME (gpad));
/* clear old target */
if ((oldtarget = GST_PROXY_PAD_TARGET (gpad))) {
/* if we have an internal pad, unlink */
if (internal) {
if (GST_PAD_IS_SRC (internal))
gst_pad_unlink (internal, oldtarget);
else
gst_pad_unlink (oldtarget, internal);
}
}
result = gst_proxy_pad_set_target_unlocked (GST_PAD_CAST (gpad), newtarget);
if (result && newtarget) {
/* and link to internal pad if we have one */
if (internal) {
if (GST_PAD_IS_SRC (internal))
result = gst_pad_link (internal, newtarget);
else
result = gst_pad_link (newtarget, internal);
}
}
GST_PROXY_UNLOCK (gpad);
return result;
}