gstreamer/gst/switch/gstswitch.c

/* GStreamer
 * Copyright (C) 2003 Julien Moutte <julien@moutte.net>
 *
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/* Object header */
#include "gstswitch.h"

enum
{
  ARG_0,
  ARG_NB_SOURCES,
  ARG_ACTIVE_SOURCE
};

GST_DEBUG_CATEGORY_STATIC (switch_debug);

/* ElementFactory information */
static const GstElementDetails gst_switch_details =
GST_ELEMENT_DETAILS ("Switch",
    "Generic",
    "N-to-1 input switching",
    "Julien Moutte <julien@moutte.net>");

static GstStaticPadTemplate gst_switch_sink_factory =
GST_STATIC_PAD_TEMPLATE ("sink%d",
    GST_PAD_SINK,
    GST_PAD_REQUEST,
    GST_STATIC_CAPS_ANY);

static GstElementClass *parent_class = NULL;

/* ============================================================= */
/*                                                               */
/*                       Private Methods                         */
/*                                                               */
/* ============================================================= */

static void
gst_switch_release_pad (GstElement * element, GstPad * pad)
{
  GList *sinkpads = NULL;
  GstSwitch *gstswitch = NULL;
  GstSwitchPad *switchpad = NULL;

  g_return_if_fail (GST_IS_SWITCH (element));

  gstswitch = GST_SWITCH (element);

  GST_LOG_OBJECT (gstswitch, "releasing requested pad %p", pad);

  sinkpads = gstswitch->sinkpads;

  /* Walking through our pad list searching for the pad we want to release */
  while (sinkpads) {
    switchpad = sinkpads->data;

    if (switchpad && switchpad->sinkpad == pad)
      break;
    else
      switchpad = NULL;

    sinkpads = g_list_next (sinkpads);
  }

  /* Releasing the found pad */
  if (switchpad) {
    /* We unref the data of that pad to loose our reference */
    gst_data_unref (switchpad->data);
    /* If data has not been forwarded we have to destroy it */
    if (!switchpad->forwarded && switchpad->data) {
      gst_data_unref (switchpad->data);
    }
    gst_element_remove_pad (element, pad);
    gstswitch->sinkpads = g_list_remove (gstswitch->sinkpads, switchpad);
    gstswitch->nb_sinkpads--;
    if (gstswitch->active_sinkpad >= gstswitch->nb_sinkpads)
      gstswitch->active_sinkpad = 0;
    g_free (switchpad);
  }
}

static GstPad *
gst_switch_request_new_pad (GstElement * element,
    GstPadTemplate * templ, const gchar * unused)
{
  char *name = NULL;
  GstPad *sinkpad = NULL;
  GstSwitch *gstswitch = NULL;
  GstSwitchPad *switchpad = NULL;

  g_return_val_if_fail (GST_IS_SWITCH (element), NULL);

  gstswitch = GST_SWITCH (element);

  /* We only provide requested sink pads */
  if (templ->direction != GST_PAD_SINK) {
    GST_LOG_OBJECT (gstswitch, "requested a non sink pad");
    return NULL;
  }

  name = g_strdup_printf ("sink%d", gstswitch->nb_sinkpads);

  sinkpad = gst_pad_new_from_template (templ, name);

  if (name)
    g_free (name);

  /* That pad will proxy caps and link */
  gst_pad_set_link_function (sinkpad,
      GST_DEBUG_FUNCPTR (gst_pad_proxy_pad_link));
  gst_pad_set_getcaps_function (sinkpad,
      GST_DEBUG_FUNCPTR (gst_pad_proxy_getcaps));

  gst_element_add_pad (GST_ELEMENT (gstswitch), sinkpad);

  switchpad = g_new0 (GstSwitchPad, 1);
  if (!switchpad)
    return NULL;

  switchpad->sinkpad = sinkpad;
  switchpad->data = NULL;
  switchpad->forwarded = FALSE;
  switchpad->eos = FALSE;

  gstswitch->sinkpads = g_list_insert (gstswitch->sinkpads, switchpad,
      gstswitch->nb_sinkpads);
  gstswitch->nb_sinkpads++;

  if (GST_PAD_CAPS (gstswitch->srcpad)) {
    gst_pad_try_set_caps (sinkpad, GST_PAD_CAPS (gstswitch->srcpad));
  }

  return sinkpad;
}

static gboolean
gst_switch_poll_sinkpads (GstSwitch * gstswitch)
{
  GList *pads;

  g_return_val_if_fail (gstswitch != NULL, FALSE);
  g_return_val_if_fail (GST_IS_SWITCH (gstswitch), FALSE);

  pads = gstswitch->sinkpads;

  while (pads) {
    GstSwitchPad *switchpad = pads->data;

    /* We only pull from usable pads and non EOS pads */
    if (GST_PAD_IS_USABLE (switchpad->sinkpad) && !switchpad->eos) {

      GST_LOG_OBJECT (gstswitch, "polling pad %p", switchpad->sinkpad);

      /* We loose the reference to the data we stored */
      if (switchpad->data) {
        gst_data_unref (switchpad->data);
      }

      /* If that data was not forwarded we unref it another time to destroy it */
      if (!switchpad->forwarded && switchpad->data) {
        gst_data_unref (switchpad->data);
      }

      switchpad->data = NULL;
      switchpad->data = gst_pad_pull (switchpad->sinkpad);

      if (!switchpad->data) {
        GST_LOG_OBJECT (gstswitch,
            "received NULL data from pad %p", switchpad->sinkpad);
      } else {
        gst_data_ref (switchpad->data);
        switchpad->forwarded = FALSE;

        /* If the buffer is an EOS event we tag the pad as being in EOS. That 
           means we won't try to pull more data from that pad */
        if (GST_IS_EVENT (switchpad->data) &&
            (GST_EVENT_TYPE (GST_EVENT (switchpad->data)) == GST_EVENT_EOS)) {
          GST_LOG_OBJECT (gstswitch,
              "received EOS event on pad %p", switchpad->sinkpad);
          switchpad->eos = TRUE;
        }
      }
    } else {
      GST_LOG_OBJECT (gstswitch,
          "not pulling from pad %s (eos is %d)",
          gst_pad_get_name (switchpad->sinkpad), switchpad->eos);
    }
    pads = g_list_next (pads);
  }

  return TRUE;
}

static void
gst_switch_loop (GstElement * element)
{
  GstSwitch *gstswitch = NULL;
  GstSwitchPad *switchpad = NULL;

  g_return_if_fail (element != NULL);
  g_return_if_fail (GST_IS_SWITCH (element));

  gstswitch = GST_SWITCH (element);

  /* We poll all our sinkpads */
  gst_switch_poll_sinkpads (gstswitch);

  /* We get the active sinkpad */
  switchpad = g_list_nth_data (gstswitch->sinkpads, gstswitch->active_sinkpad);

  if (switchpad && switchpad->data) {
    GstData *data = switchpad->data;

    /* Loose our reference to that data */
    gst_data_unref (switchpad->data);
    switchpad->data = NULL;

    GST_LOG_OBJECT (gstswitch,
        "using data from active pad %p", switchpad->sinkpad);

    if (GST_IS_EVENT (data)) {
      GstEvent *event = GST_EVENT (data);

      GST_LOG_OBJECT (gstswitch,
          "handling event from active pad %p", switchpad->sinkpad);
      /* Handling event */
      gst_pad_event_default (switchpad->sinkpad, event);
    } else {
      /* Pushing active sinkpad data to srcpad */
      GST_LOG_OBJECT (gstswitch,
          "pushing data from active pad %p to %p",
          switchpad->sinkpad, gstswitch->srcpad);
      gst_pad_push (gstswitch->srcpad, data);
    }

    /* Mark this data as forwarded so that it won't get unrefed on next poll */
    switchpad->forwarded = TRUE;
  }
}

static GstStateChangeReturn
gst_switch_change_state (GstElement * element, GstStateChange transition)
{
  GstSwitch *gstswitch;

  gstswitch = GST_SWITCH (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
      break;
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
    {
      GList *sinkpads = NULL;

      sinkpads = gstswitch->sinkpads;

      while (sinkpads) {
        GstSwitchPad *switchpad = sinkpads->data;

        /* If a data is still stored in our structure we unref it */
        if (switchpad->data) {
          gst_data_unref (switchpad->data);
          switchpad->data = NULL;
        }

        switchpad->forwarded = FALSE;
        switchpad->eos = FALSE;

        sinkpads = g_list_next (sinkpads);
      }
    }
      break;
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      break;
  }

  if (GST_ELEMENT_CLASS (parent_class)->change_state)
    return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
  else
    return GST_STATE_CHANGE_SUCCESS;
}

/* =========================================== */
/*                                             */
/*                 Properties                  */
/*                                             */
/* =========================================== */

static void
gst_switch_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstSwitch *gstswitch = NULL;

  g_return_if_fail (GST_IS_SWITCH (object));

  gstswitch = GST_SWITCH (object);

  switch (prop_id) {
    case ARG_ACTIVE_SOURCE:
      gstswitch->active_sinkpad = g_value_get_int (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_switch_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstSwitch *gstswitch = NULL;

  g_return_if_fail (GST_IS_SWITCH (object));

  gstswitch = GST_SWITCH (object);

  switch (prop_id) {
    case ARG_ACTIVE_SOURCE:
      g_value_set_int (value, gstswitch->active_sinkpad);
      break;
    case ARG_NB_SOURCES:
      g_value_set_int (value, gstswitch->nb_sinkpads);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

/* =========================================== */
/*                                             */
/*              Init & Class init              */
/*                                             */
/* =========================================== */

static void
gst_switch_dispose (GObject * object)
{
  GstSwitch *gstswitch = NULL;
  GList *sinkpads = NULL;

  gstswitch = GST_SWITCH (object);

  sinkpads = gstswitch->sinkpads;

  while (sinkpads) {
    GstSwitchPad *switchpad = sinkpads->data;

    /* If a data is still stored in our structure we unref it */
    if (switchpad->data) {
      gst_data_unref (switchpad->data);
      switchpad->data = NULL;
    }

    /* Freeing our structure */
    g_free (switchpad);

    sinkpads = g_list_next (sinkpads);
  }

  /* Freeing the list correctly */
  if (gstswitch->sinkpads) {
    g_list_free (gstswitch->sinkpads);
    gstswitch->sinkpads = NULL;
  }

  G_OBJECT_CLASS (parent_class)->dispose (object);
}

static void
gst_switch_init (GstSwitch * gstswitch)
{
  gstswitch->srcpad = gst_pad_new ("src", GST_PAD_SRC);
  gst_element_add_pad (GST_ELEMENT (gstswitch), gstswitch->srcpad);
  gst_pad_set_link_function (gstswitch->srcpad,
      GST_DEBUG_FUNCPTR (gst_pad_proxy_pad_link));
  gst_pad_set_getcaps_function (gstswitch->srcpad,
      GST_DEBUG_FUNCPTR (gst_pad_proxy_getcaps));
  gst_element_set_loop_function (GST_ELEMENT (gstswitch), gst_switch_loop);

  gstswitch->sinkpads = NULL;
  gstswitch->active_sinkpad = 0;
  gstswitch->nb_sinkpads = 0;
}

static void
gst_switch_base_init (gpointer g_class)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_set_details (element_class, &gst_switch_details);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_switch_sink_factory));
}

static void
gst_switch_class_init (GstSwitchClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_peek_parent (klass);

  g_object_class_install_property (gobject_class,
      ARG_NB_SOURCES,
      g_param_spec_int ("nb_sources",
          "number of sources",
          "number of sources", G_MININT, G_MAXINT, 0, G_PARAM_READABLE));
  g_object_class_install_property (gobject_class,
      ARG_ACTIVE_SOURCE,
      g_param_spec_int ("active_source",
          "active source",
          "active source", G_MININT, G_MAXINT, 0, G_PARAM_READWRITE));

  gobject_class->dispose = gst_switch_dispose;
  gobject_class->set_property = gst_switch_set_property;
  gobject_class->get_property = gst_switch_get_property;

  gstelement_class->change_state = gst_switch_change_state;
  gstelement_class->request_new_pad = gst_switch_request_new_pad;
  gstelement_class->release_pad = gst_switch_release_pad;
}

/* ============================================================= */
/*                                                               */
/*                       Public Methods                          */
/*                                                               */
/* ============================================================= */

GType
gst_switch_get_type (void)
{
  static GType switch_type = 0;

  if (!switch_type) {
    static const GTypeInfo switch_info = {
      sizeof (GstSwitchClass),
      gst_switch_base_init,
      NULL,
      (GClassInitFunc) gst_switch_class_init,
      NULL,
      NULL,
      sizeof (GstSwitch),
      0,
      (GInstanceInitFunc) gst_switch_init,
    };

    switch_type = g_type_register_static (GST_TYPE_ELEMENT,
        "GstSwitch", &switch_info, 0);

    GST_DEBUG_CATEGORY_INIT (switch_debug, "switch", 0, "the switch element");
  }

  return switch_type;
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  return gst_element_register (plugin, "switch", GST_RANK_NONE,
      GST_TYPE_SWITCH);
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "switch",
    "N-to-1 input switching",
    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)