/* 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 (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)

{

  g_type_class_add_private (klass, sizeof (GstProxyPadPrivate));

  /* 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) = G_TYPE_INSTANCE_GET_PRIVATE (ppad,

      GST_TYPE_PROXY_PAD, GstProxyPadPrivate);

  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)

 */

#define GST_GHOST_PAD_PRIVATE(obj)	(GST_GHOST_PAD_CAST (obj)->priv)

struct _GstGhostPadPrivate

{

  /* with PROXY_LOCK */

  gboolean constructed;

};

G_DEFINE_TYPE (GstGhostPad, gst_ghost_pad, GST_TYPE_PROXY_PAD);

static void gst_ghost_pad_dispose (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;

  g_type_class_add_private (klass, sizeof (GstGhostPadPrivate));

  gobject_class->dispose = gst_ghost_pad_dispose;

  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_GHOST_PAD_PRIVATE (pad) = G_TYPE_INSTANCE_GET_PRIVATE (pad,

      GST_TYPE_GHOST_PAD, GstGhostPadPrivate);

  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);

}

/**

 * 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).

 *

 * Returns: %TRUE if the construction succeeds, %FALSE otherwise.

 */

gboolean

gst_ghost_pad_construct (GstGhostPad * gpad)

{

  GstPadDirection dir, otherdir;

  GstPadTemplate *templ;

  GstPad *pad, *internal;

  g_return_val_if_fail (GST_IS_GHOST_PAD (gpad), FALSE);

  g_return_val_if_fail (!GST_GHOST_PAD_PRIVATE (gpad)->constructed, FALSE);

  g_object_get (gpad, "direction", &dir, "template", &templ, NULL);

  g_return_val_if_fail (dir != GST_PAD_UNKNOWN, FALSE);

  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);

  }

  GST_OBJECT_LOCK (pad);

  /* now make the ghostpad a parent of the internal pad */

  if (!gst_object_set_parent (GST_OBJECT_CAST (internal),

          GST_OBJECT_CAST (pad)))

    goto parent_failed;

  /* 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);

  GST_OBJECT_UNLOCK (pad);

  GST_GHOST_PAD_PRIVATE (gpad)->constructed = TRUE;

  return TRUE;

  /* ERRORS */

parent_failed:

  {

    GST_WARNING_OBJECT (gpad, "Could not set internal pad %s:%s",

        GST_DEBUG_PAD_NAME (internal));

    g_critical ("Could not set internal pad %s:%s",

        GST_DEBUG_PAD_NAME (internal));

    GST_OBJECT_UNLOCK (pad);

    return FALSE;

  }

}

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);

  }

  if (!gst_ghost_pad_construct (ret))

    goto construct_failed;

  return GST_PAD_CAST (ret);

construct_failed:

  /* already logged */

  gst_object_unref (ret);

  return NULL;

}

/**

 * 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);