gstreamer/gst/gstghostpad.c
Sebastian Dröge 63c1945695 ghostpad: Deprecate gst_ghost_pad_construct()
Instead do everything it did as part of GObject::constructed() and
change the function to always return TRUE.

gst_ghost_pad_construct() was meant to be called by subclasses right
after construction of the object to finish construction as it can fail
in theory. In practice it's impossible for it to fail, even more so if
called directly from GObject::constructed(): The only failure condition
is if the newly created proxy pad already has a parent, which is
impossible at this point as nothing else can have a reference to it.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/540>
2020-06-22 12:30:48 +03:00

865 lines
26 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>
* 2006 Edward Hervey <bilboed@bilboed.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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstghostpad
* @title: 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 any
* other #GstElement. 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 associated 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
* association later on.
*
* Note that GhostPads add overhead to the data processing of a pipeline.
*/
#include "gst_private.h"
#include "gstinfo.h"
#include "gstghostpad.h"
#include "gst.h"
#define GST_CAT_DEFAULT GST_CAT_PADS
#define GST_PROXY_PAD_CAST(obj) ((GstProxyPad *)obj)
#define GST_PROXY_PAD_PRIVATE(obj) (GST_PROXY_PAD_CAST (obj)->priv)
#define GST_PROXY_PAD_TARGET(pad) (GST_PAD_PEER (GST_PROXY_PAD_INTERNAL (pad)))
#define GST_PROXY_PAD_INTERNAL(pad) (GST_PROXY_PAD_PRIVATE (pad)->internal)
#define GST_PROXY_PAD_ACQUIRE_INTERNAL(pad, internal, retval) \
internal = \
GST_PAD_CAST (gst_proxy_pad_get_internal (GST_PROXY_PAD_CAST (pad))); \
if (internal == NULL) \
return retval;
#define GST_PROXY_PAD_RELEASE_INTERNAL(internal) gst_object_unref (internal);
struct _GstProxyPadPrivate
{
GstPad *internal;
};
G_DEFINE_TYPE_WITH_PRIVATE (GstProxyPad, gst_proxy_pad, GST_TYPE_PAD);
static GstPad *gst_proxy_pad_get_target (GstPad * pad);
/**
* gst_proxy_pad_iterate_internal_links_default:
* @pad: the #GstPad to get the internal links of.
* @parent: (allow-none): the parent of @pad or %NULL
*
* Invoke the default iterate internal links function of the proxy pad.
*
* Returns: (nullable): a #GstIterator of #GstPad, or %NULL if @pad
* has no parent. Unref each returned pad with gst_object_unref().
*/
GstIterator *
gst_proxy_pad_iterate_internal_links_default (GstPad * pad, GstObject * parent)
{
GstIterator *res = NULL;
GstPad *internal;
GValue v = { 0, };
g_return_val_if_fail (GST_IS_PROXY_PAD (pad), NULL);
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, NULL);
g_value_init (&v, GST_TYPE_PAD);
g_value_take_object (&v, internal);
res = gst_iterator_new_single (GST_TYPE_PAD, &v);
g_value_unset (&v);
return res;
}
/**
* gst_proxy_pad_chain_default:
* @pad: a sink #GstPad, returns GST_FLOW_ERROR if not.
* @parent: (allow-none): the parent of @pad or %NULL
* @buffer: (transfer full): the #GstBuffer to send, return GST_FLOW_ERROR
* if not.
*
* Invoke the default chain function of the proxy pad.
*
* Returns: a #GstFlowReturn from the pad.
*/
GstFlowReturn
gst_proxy_pad_chain_default (GstPad * pad, GstObject * parent,
GstBuffer * buffer)
{
GstFlowReturn res;
GstPad *internal;
g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
g_return_val_if_fail (GST_IS_BUFFER (buffer), GST_FLOW_ERROR);
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, GST_FLOW_NOT_LINKED);
res = gst_pad_push (internal, buffer);
GST_PROXY_PAD_RELEASE_INTERNAL (internal);
return res;
}
/**
* gst_proxy_pad_chain_list_default:
* @pad: a sink #GstPad, returns GST_FLOW_ERROR if not.
* @parent: (allow-none): the parent of @pad or %NULL
* @list: (transfer full): the #GstBufferList to send, return GST_FLOW_ERROR
* if not.
*
* Invoke the default chain list function of the proxy pad.
*
* Returns: a #GstFlowReturn from the pad.
*/
GstFlowReturn
gst_proxy_pad_chain_list_default (GstPad * pad, GstObject * parent,
GstBufferList * list)
{
GstFlowReturn res;
GstPad *internal;
g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
g_return_val_if_fail (GST_IS_BUFFER_LIST (list), GST_FLOW_ERROR);
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, GST_FLOW_NOT_LINKED);
res = gst_pad_push_list (internal, list);
GST_PROXY_PAD_RELEASE_INTERNAL (internal);
return res;
}
/**
* gst_proxy_pad_getrange_default:
* @pad: a src #GstPad, returns #GST_FLOW_ERROR if not.
* @parent: the parent of @pad
* @offset: The start offset of the buffer
* @size: The length of the buffer
* @buffer: (out callee-allocates): a pointer to hold the #GstBuffer,
* returns #GST_FLOW_ERROR if %NULL.
*
* Invoke the default getrange function of the proxy pad.
*
* Returns: a #GstFlowReturn from the pad.
*/
GstFlowReturn
gst_proxy_pad_getrange_default (GstPad * pad, GstObject * parent,
guint64 offset, guint size, GstBuffer ** buffer)
{
GstFlowReturn res;
GstPad *internal;
g_return_val_if_fail (GST_IS_PROXY_PAD (pad), GST_FLOW_ERROR);
g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, internal, GST_FLOW_NOT_LINKED);
res = gst_pad_pull_range (internal, offset, size, buffer);
GST_PROXY_PAD_RELEASE_INTERNAL (internal);
return res;
}
static GstPad *
gst_proxy_pad_get_target (GstPad * pad)
{
GstPad *target;
GST_OBJECT_LOCK (pad);
target = gst_pad_get_peer (GST_PROXY_PAD_INTERNAL (pad));
GST_OBJECT_UNLOCK (pad);
return target;
}
/**
* gst_proxy_pad_get_internal:
* @pad: the #GstProxyPad
*
* Get the internal pad of @pad. Unref target pad after usage.
*
* The internal pad of a #GstGhostPad is the internally used
* pad of opposite direction, which is used to link to the target.
*
* Returns: (transfer full) (nullable): the target #GstProxyPad, can
* be %NULL. Unref target pad after usage.
*/
GstProxyPad *
gst_proxy_pad_get_internal (GstProxyPad * pad)
{
GstPad *internal;
g_return_val_if_fail (GST_IS_PROXY_PAD (pad), NULL);
GST_OBJECT_LOCK (pad);
internal = GST_PROXY_PAD_INTERNAL (pad);
if (internal)
gst_object_ref (internal);
GST_OBJECT_UNLOCK (pad);
return GST_PROXY_PAD_CAST (internal);
}
static void
gst_proxy_pad_class_init (GstProxyPadClass * klass)
{
/* Register common function pointer descriptions */
GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_iterate_internal_links_default);
GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_chain_default);
GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_chain_list_default);
GST_DEBUG_REGISTER_FUNCPTR (gst_proxy_pad_getrange_default);
}
static void
gst_proxy_pad_init (GstProxyPad * ppad)
{
GstPad *pad = (GstPad *) ppad;
GST_PROXY_PAD_PRIVATE (ppad) = gst_proxy_pad_get_instance_private (ppad);
gst_pad_set_iterate_internal_links_function (pad,
gst_proxy_pad_iterate_internal_links_default);
GST_PAD_SET_PROXY_CAPS (pad);
GST_PAD_SET_PROXY_SCHEDULING (pad);
GST_PAD_SET_PROXY_ALLOCATION (pad);
}
/***********************************************************************
* Ghost pads, implemented as a pair of proxy pads (sort of)
*/
G_DEFINE_TYPE (GstGhostPad, gst_ghost_pad, GST_TYPE_PROXY_PAD);
static void gst_ghost_pad_dispose (GObject * object);
static void gst_ghost_pad_constructed (GObject * object);
static gboolean
gst_ghost_pad_internal_activate_push_default (GstPad * pad, GstObject * parent,
gboolean active)
{
gboolean ret;
GstPad *other;
GST_LOG_OBJECT (pad, "%sactivate push on %s:%s, we're ok",
(active ? "" : "de"), GST_DEBUG_PAD_NAME (pad));
/* in both cases (SRC and SINK) we activate just the internal pad. The targets
* will be activated later (or already in case of a ghost sinkpad). */
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
ret = gst_pad_activate_mode (other, GST_PAD_MODE_PUSH, active);
GST_PROXY_PAD_RELEASE_INTERNAL (other);
return ret;
}
static gboolean
gst_ghost_pad_internal_activate_pull_default (GstPad * pad, GstObject * parent,
gboolean active)
{
gboolean ret;
GstPad *other;
GST_LOG_OBJECT (pad, "%sactivate pull on %s:%s", (active ? "" : "de"),
GST_DEBUG_PAD_NAME (pad));
if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
/* we are activated in pull mode by our peer element, which is a sinkpad
* that wants to operate in pull mode. This activation has to propagate
* upstream through the pipeline. We call the internal activation function,
* which will trigger gst_ghost_pad_activate_pull_default, which propagates even
* further upstream */
GST_LOG_OBJECT (pad, "pad is src, activate internal");
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
GST_PROXY_PAD_RELEASE_INTERNAL (other);
} else if (G_LIKELY ((other = gst_pad_get_peer (pad)))) {
/* We are SINK, the ghostpad is SRC, we propagate the activation upstream
* since we hold a pointer to the upstream peer. */
GST_LOG_OBJECT (pad, "activating peer");
ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
gst_object_unref (other);
} else if (active) {
/* this is failure, we can't activate pull if there is no peer */
GST_LOG_OBJECT (pad, "not src and no peer, failing");
ret = FALSE;
} else {
GST_LOG_OBJECT (pad, "deactivating pull, with no peer - allowing");
ret = TRUE;
}
return ret;
}
/**
* gst_ghost_pad_internal_activate_mode_default:
* @pad: the #GstPad to activate or deactivate.
* @parent: (allow-none): the parent of @pad or %NULL
* @mode: the requested activation mode
* @active: whether the pad should be active or not.
*
* Invoke the default activate mode function of a proxy pad that is
* owned by a ghost pad.
*
* Returns: %TRUE if the operation was successful.
*/
gboolean
gst_ghost_pad_internal_activate_mode_default (GstPad * pad, GstObject * parent,
GstPadMode mode, gboolean active)
{
gboolean res;
g_return_val_if_fail (GST_IS_PROXY_PAD (pad), FALSE);
switch (mode) {
case GST_PAD_MODE_PULL:
res = gst_ghost_pad_internal_activate_pull_default (pad, parent, active);
break;
case GST_PAD_MODE_PUSH:
res = gst_ghost_pad_internal_activate_push_default (pad, parent, active);
break;
default:
GST_LOG_OBJECT (pad, "unknown activation mode %d", mode);
res = FALSE;
break;
}
return res;
}
static gboolean
gst_ghost_pad_activate_push_default (GstPad * pad, GstObject * parent,
gboolean active)
{
gboolean ret;
GstPad *other;
g_return_val_if_fail (GST_IS_GHOST_PAD (pad), FALSE);
GST_LOG_OBJECT (pad, "%sactivate push on %s:%s, proxy internal",
(active ? "" : "de"), GST_DEBUG_PAD_NAME (pad));
/* just activate the internal pad */
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
ret = gst_pad_activate_mode (other, GST_PAD_MODE_PUSH, active);
GST_PROXY_PAD_RELEASE_INTERNAL (other);
return ret;
}
static gboolean
gst_ghost_pad_activate_pull_default (GstPad * pad, GstObject * parent,
gboolean active)
{
gboolean ret;
GstPad *other;
GST_LOG_OBJECT (pad, "%sactivate pull on %s:%s", (active ? "" : "de"),
GST_DEBUG_PAD_NAME (pad));
if (GST_PAD_DIRECTION (pad) == GST_PAD_SRC) {
/* the ghostpad is SRC and activated in pull mode by its peer, call the
* activation function of the internal pad to propagate the activation
* upstream */
GST_LOG_OBJECT (pad, "pad is src, activate internal");
GST_PROXY_PAD_ACQUIRE_INTERNAL (pad, other, FALSE);
ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
GST_PROXY_PAD_RELEASE_INTERNAL (other);
} else if (G_LIKELY ((other = gst_pad_get_peer (pad)))) {
/* We are SINK and activated by the internal pad, propagate activation
* upstream because we hold a ref to the upstream peer */
GST_LOG_OBJECT (pad, "activating peer");
ret = gst_pad_activate_mode (other, GST_PAD_MODE_PULL, active);
gst_object_unref (other);
} else if (active) {
/* this is failure, we can't activate pull if there is no peer */
GST_LOG_OBJECT (pad, "not src and no peer, failing");
ret = FALSE;
} else {
GST_LOG_OBJECT (pad, "deactivating pull, with no peer - allowing");
ret = TRUE;
}
return ret;
}
/**
* gst_ghost_pad_activate_mode_default:
* @pad: the #GstPad to activate or deactivate.
* @parent: (allow-none): the parent of @pad or %NULL
* @mode: the requested activation mode
* @active: whether the pad should be active or not.
*
* Invoke the default activate mode function of a ghost pad.
*
* Returns: %TRUE if the operation was successful.
*/
gboolean
gst_ghost_pad_activate_mode_default (GstPad * pad, GstObject * parent,
GstPadMode mode, gboolean active)
{
gboolean res;
g_return_val_if_fail (GST_IS_GHOST_PAD (pad), FALSE);
switch (mode) {
case GST_PAD_MODE_PULL:
res = gst_ghost_pad_activate_pull_default (pad, parent, active);
break;
case GST_PAD_MODE_PUSH:
res = gst_ghost_pad_activate_push_default (pad, parent, active);
break;
default:
GST_LOG_OBJECT (pad, "unknown activation mode %d", mode);
res = FALSE;
break;
}
return res;
}
static void
gst_ghost_pad_class_init (GstGhostPadClass * klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
gobject_class->dispose = gst_ghost_pad_dispose;
gobject_class->constructed = gst_ghost_pad_constructed;
GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_activate_pull_default);
GST_DEBUG_REGISTER_FUNCPTR (gst_ghost_pad_activate_push_default);
}
static void
gst_ghost_pad_init (GstGhostPad * pad)
{
gst_pad_set_activatemode_function (GST_PAD_CAST (pad),
gst_ghost_pad_activate_mode_default);
}
static void
gst_ghost_pad_dispose (GObject * object)
{
GstPad *pad;
GstPad *internal;
GstPad *peer;
pad = GST_PAD (object);
GST_DEBUG_OBJECT (pad, "dispose");
gst_ghost_pad_set_target (GST_GHOST_PAD (pad), NULL);
/* Unlink here so that gst_pad_dispose doesn't. That would lead to a call to
* gst_ghost_pad_unlink_default when the ghost pad is in an inconsistent state */
peer = gst_pad_get_peer (pad);
if (peer) {
if (GST_PAD_IS_SRC (pad))
gst_pad_unlink (pad, peer);
else
gst_pad_unlink (peer, pad);
gst_object_unref (peer);
}
GST_OBJECT_LOCK (pad);
internal = GST_PROXY_PAD_INTERNAL (pad);
if (internal) {
gst_pad_set_activatemode_function (internal, NULL);
GST_PROXY_PAD_INTERNAL (pad) = NULL;
GST_PROXY_PAD_INTERNAL (internal) = NULL;
/* disposes of the internal pad, since the ghostpad is the only possible object
* that has a refcount on the internal pad. */
gst_object_unparent (GST_OBJECT_CAST (internal));
}
GST_OBJECT_UNLOCK (pad);
G_OBJECT_CLASS (gst_ghost_pad_parent_class)->dispose (object);
}
static void
gst_ghost_pad_constructed (GObject * object)
{
GstGhostPad *gpad = GST_GHOST_PAD (object);
GstPadDirection dir, otherdir;
GstPadTemplate *templ;
GstPad *pad, *internal;
G_OBJECT_CLASS (gst_ghost_pad_parent_class)->constructed (object);
g_object_get (gpad, "direction", &dir, "template", &templ, NULL);
g_return_if_fail (dir != GST_PAD_UNKNOWN);
pad = GST_PAD (gpad);
/* Set directional padfunctions for ghostpad */
if (dir == GST_PAD_SINK) {
gst_pad_set_chain_function (pad, gst_proxy_pad_chain_default);
gst_pad_set_chain_list_function (pad, gst_proxy_pad_chain_list_default);
} else {
gst_pad_set_getrange_function (pad, gst_proxy_pad_getrange_default);
}
/* INTERNAL PAD, it always exists and is child of the ghostpad */
otherdir = (dir == GST_PAD_SRC) ? GST_PAD_SINK : GST_PAD_SRC;
if (templ) {
internal =
g_object_new (GST_TYPE_PROXY_PAD, "name", NULL,
"direction", otherdir, "template", templ, NULL);
/* release ref obtained via g_object_get */
gst_object_unref (templ);
} else {
internal =
g_object_new (GST_TYPE_PROXY_PAD, "name", NULL,
"direction", otherdir, NULL);
}
GST_PAD_UNSET_FLUSHING (internal);
/* Set directional padfunctions for internal pad */
if (dir == GST_PAD_SRC) {
gst_pad_set_chain_function (internal, gst_proxy_pad_chain_default);
gst_pad_set_chain_list_function (internal,
gst_proxy_pad_chain_list_default);
} else {
gst_pad_set_getrange_function (internal, gst_proxy_pad_getrange_default);
}
/* now make the ghostpad a parent of the internal pad */
gst_object_set_parent (GST_OBJECT_CAST (internal), GST_OBJECT_CAST (pad));
/* The ghostpad is the parent of the internal pad and is the only object that
* can have a refcount on the internal pad.
* At this point, the GstGhostPad has a refcount of 1, and the internal pad has
* a refcount of 1.
* When the refcount of the GstGhostPad drops to 0, the ghostpad will dispose
* its refcount on the internal pad in the dispose method by un-parenting it.
* This is why we don't take extra refcounts in the assignments below
*/
GST_PROXY_PAD_INTERNAL (pad) = internal;
GST_PROXY_PAD_INTERNAL (internal) = pad;
/* special activation functions for the internal pad */
gst_pad_set_activatemode_function (internal,
gst_ghost_pad_internal_activate_mode_default);
}
#ifndef GST_REMOVE_DEPRECATED
/**
* gst_ghost_pad_construct:
* @gpad: the newly allocated ghost pad
*
* Finish initialization of a newly allocated ghost pad.
*
* This function is most useful in language bindings and when subclassing
* #GstGhostPad; plugin and application developers normally will not call this
* function. Call this function directly after a call to g_object_new
* (GST_TYPE_GHOST_PAD, "direction", @dir, ..., NULL).
*
* Deprecated: This function is deprecated since 1.18 and does nothing
* anymore.
*
* Returns: %TRUE if the construction succeeds, %FALSE otherwise.
*/
gboolean
gst_ghost_pad_construct (GstGhostPad * gpad)
{
return TRUE;
}
#endif
static GstPad *
gst_ghost_pad_new_full (const gchar * name, GstPadDirection dir,
GstPadTemplate * templ)
{
GstGhostPad *ret;
g_return_val_if_fail (dir != GST_PAD_UNKNOWN, NULL);
/* OBJECT CREATION */
if (templ) {
GType pad_type =
GST_PAD_TEMPLATE_GTYPE (templ) ==
G_TYPE_NONE ? GST_TYPE_GHOST_PAD : GST_PAD_TEMPLATE_GTYPE (templ);
g_return_val_if_fail (g_type_is_a (pad_type, GST_TYPE_GHOST_PAD), NULL);
ret = g_object_new (pad_type, "name", name,
"direction", dir, "template", templ, NULL);
} else {
ret = g_object_new (GST_TYPE_GHOST_PAD, "name", name,
"direction", dir, NULL);
}
return GST_PAD_CAST (ret);
}
/**
* gst_ghost_pad_new_no_target:
* @name: (allow-none): 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: (transfer floating) (nullable): a new #GstPad, or %NULL in
* case of an error.
*/
GstPad *
gst_ghost_pad_new_no_target (const gchar * name, GstPadDirection dir)
{
GstPad *ret;
g_return_val_if_fail (dir != GST_PAD_UNKNOWN, NULL);
GST_LOG ("name:%s, direction:%d", GST_STR_NULL (name), dir);
ret = gst_ghost_pad_new_full (name, dir, NULL);
return ret;
}
/**
* gst_ghost_pad_new:
* @name: (allow-none): the name of the new pad, or %NULL to assign a default name
* @target: (transfer none): the pad to ghost.
*
* Create a new ghostpad with @target as the target. The direction will be taken
* from the target pad. @target must be unlinked.
*
* Will ref the target.
*
* Returns: (transfer floating) (nullable): 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);
GST_LOG ("name:%s, target:%s:%s", GST_STR_NULL (name),
GST_DEBUG_PAD_NAME (target));
if ((ret = gst_ghost_pad_new_no_target (name, GST_PAD_DIRECTION (target))))
if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (ret), target))
goto set_target_failed;
return ret;
/* ERRORS */
set_target_failed:
{
GST_WARNING_OBJECT (ret, "failed to set target %s:%s",
GST_DEBUG_PAD_NAME (target));
gst_object_unref (ret);
return NULL;
}
}
/**
* gst_ghost_pad_new_from_template:
* @name: (allow-none): the name of the new pad, or %NULL to assign a default name.
* @target: (transfer none): the pad to ghost.
* @templ: (transfer none): the #GstPadTemplate to use on the ghostpad.
*
* Create a new ghostpad with @target as the target. The direction will be taken
* from the target pad. The template used on the ghostpad will be @template.
*
* Will ref the target.
*
* Returns: (transfer floating) (nullable): a new #GstPad, or %NULL in
* case of an error.
*/
GstPad *
gst_ghost_pad_new_from_template (const gchar * name, GstPad * target,
GstPadTemplate * templ)
{
GstPad *ret;
g_return_val_if_fail (GST_IS_PAD (target), NULL);
g_return_val_if_fail (!gst_pad_is_linked (target), NULL);
g_return_val_if_fail (templ != NULL, NULL);
g_return_val_if_fail (GST_PAD_TEMPLATE_DIRECTION (templ) ==
GST_PAD_DIRECTION (target), NULL);
GST_LOG ("name:%s, target:%s:%s, templ:%p", GST_STR_NULL (name),
GST_DEBUG_PAD_NAME (target), templ);
if ((ret = gst_ghost_pad_new_full (name, GST_PAD_DIRECTION (target), templ)))
if (!gst_ghost_pad_set_target (GST_GHOST_PAD_CAST (ret), target))
goto set_target_failed;
return ret;
/* ERRORS */
set_target_failed:
{
GST_WARNING_OBJECT (ret, "failed to set target %s:%s",
GST_DEBUG_PAD_NAME (target));
gst_object_unref (ret);
return NULL;
}
}
/**
* gst_ghost_pad_new_no_target_from_template:
* @name: (allow-none): the name of the new pad, or %NULL to assign a default name
* @templ: (transfer none): the #GstPadTemplate to create the ghostpad from.
*
* Create a new ghostpad based on @templ, without setting a target. The
* direction will be taken from the @templ.
*
* Returns: (transfer floating) (nullable): a new #GstPad, or %NULL in
* case of an error.
*/
GstPad *
gst_ghost_pad_new_no_target_from_template (const gchar * name,
GstPadTemplate * templ)
{
GstPad *ret;
g_return_val_if_fail (templ != NULL, NULL);
ret =
gst_ghost_pad_new_full (name, GST_PAD_TEMPLATE_DIRECTION (templ), templ);
return ret;
}
/**
* gst_ghost_pad_get_target:
* @gpad: the #GstGhostPad
*
* Get the target pad of @gpad. Unref target pad after usage.
*
* Returns: (transfer full) (nullable): 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)
{
GstPad *ret;
g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), NULL);
ret = gst_proxy_pad_get_target (GST_PAD_CAST (gpad));
GST_DEBUG_OBJECT (gpad, "get target %s:%s", GST_DEBUG_PAD_NAME (ret));
return ret;
}
/**
* gst_ghost_pad_set_target:
* @gpad: the #GstGhostPad
* @newtarget: (transfer none) (allow-none): 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. if @newtarget is
* %NULL the target will be cleared.
*
* Returns: %TRUE if the new target could be set. This function
* can return %FALSE when the internal pads could not be linked.
*/
gboolean
gst_ghost_pad_set_target (GstGhostPad * gpad, GstPad * newtarget)
{
GstPad *internal;
GstPad *oldtarget;
GstPadLinkReturn lret;
g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);
g_return_val_if_fail (GST_PAD_CAST (gpad) != newtarget, FALSE);
GST_OBJECT_LOCK (gpad);
internal = GST_PROXY_PAD_INTERNAL (gpad);
if (newtarget == internal) {
GST_OBJECT_UNLOCK (gpad);
GST_WARNING_OBJECT (gpad, "Target has already been set to %s:%s",
GST_DEBUG_PAD_NAME (newtarget));
return TRUE;
}
if (newtarget)
GST_DEBUG_OBJECT (gpad, "set target %s:%s", GST_DEBUG_PAD_NAME (newtarget));
else
GST_DEBUG_OBJECT (gpad, "clearing target");
/* clear old target */
if ((oldtarget = gst_pad_get_peer (internal))) {
GST_OBJECT_UNLOCK (gpad);
/* unlink internal pad */
if (GST_PAD_IS_SRC (internal))
gst_pad_unlink (internal, oldtarget);
else
gst_pad_unlink (oldtarget, internal);
gst_object_unref (oldtarget);
} else {
GST_OBJECT_UNLOCK (gpad);
}
if (newtarget) {
/* and link to internal pad without any checks */
GST_DEBUG_OBJECT (gpad, "connecting internal pad to target %"
GST_PTR_FORMAT, newtarget);
if (GST_PAD_IS_SRC (internal))
lret =
gst_pad_link_full (internal, newtarget, GST_PAD_LINK_CHECK_NOTHING);
else
lret =
gst_pad_link_full (newtarget, internal, GST_PAD_LINK_CHECK_NOTHING);
if (lret != GST_PAD_LINK_OK)
goto link_failed;
}
return TRUE;
/* ERRORS */
link_failed:
{
GST_WARNING_OBJECT (gpad, "could not link internal and target, reason:%s",
gst_pad_link_get_name (lret));
return FALSE;
}
}