/* GStreamer valve element

 *  Copyright 2007-2009 Collabora Ltd

 *   @author: Olivier Crete <olivier.crete@collabora.co.uk>

 *  Copyright 2007-2009 Nokia Corporation

 *

 * 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:element-valve

 * @title: valve

 *

 * The valve is a simple element that drops buffers when the #GstValve:drop

 * property is set to %TRUE and lets then through otherwise.

 *

 * Any downstream error received while the #GstValve:drop property is %TRUE

 * is ignored. So downstream element can be set to  %GST_STATE_NULL and removed,

 * without using pad blocking.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "gstvalve.h"

#include <string.h>

GST_DEBUG_CATEGORY_STATIC (valve_debug);

#define GST_CAT_DEFAULT (valve_debug)

static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",

    GST_PAD_SINK,

    GST_PAD_ALWAYS,

    GST_STATIC_CAPS_ANY);

static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",

    GST_PAD_SRC,

    GST_PAD_ALWAYS,

    GST_STATIC_CAPS_ANY);

enum

{

  PROP_0,

  PROP_DROP

};

#define DEFAULT_DROP FALSE

static void gst_valve_set_property (GObject * object,

    guint prop_id, const GValue * value, GParamSpec * pspec);

static void gst_valve_get_property (GObject * object,

    guint prop_id, GValue * value, GParamSpec * pspec);

static GstFlowReturn gst_valve_chain (GstPad * pad, GstObject * parent,

    GstBuffer * buffer);

static gboolean gst_valve_sink_event (GstPad * pad, GstObject * parent,

    GstEvent * event);

static gboolean gst_valve_query (GstPad * pad, GstObject * parent,

    GstQuery * query);

#define _do_init \

  GST_DEBUG_CATEGORY_INIT (valve_debug, "valve", 0, "Valve");

#define gst_valve_parent_class parent_class

G_DEFINE_TYPE_WITH_CODE (GstValve, gst_valve, GST_TYPE_ELEMENT, _do_init);

static void

gst_valve_class_init (GstValveClass * klass)

{

  GObjectClass *gobject_class;

  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;

  gstelement_class = (GstElementClass *) (klass);

  gobject_class->set_property = gst_valve_set_property;

  gobject_class->get_property = gst_valve_get_property;

  g_object_class_install_property (gobject_class, PROP_DROP,

      g_param_spec_boolean ("drop", "Drop buffers and events",

          "Whether to drop buffers and events or let them through",

          DEFAULT_DROP, G_PARAM_READWRITE | GST_PARAM_MUTABLE_PLAYING |

          G_PARAM_STATIC_STRINGS));

  gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);

  gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);

  gst_element_class_set_static_metadata (gstelement_class, "Valve element",

      "Filter", "Drops buffers and events or lets them through",

      "Olivier Crete <olivier.crete@collabora.co.uk>");

}

static void

gst_valve_init (GstValve * valve)

{

  valve->drop = FALSE;

  valve->discont = FALSE;

  valve->srcpad = gst_pad_new_from_static_template (&srctemplate, "src");

  gst_pad_set_query_function (valve->srcpad,

      GST_DEBUG_FUNCPTR (gst_valve_query));

  GST_PAD_SET_PROXY_CAPS (valve->srcpad);

  gst_element_add_pad (GST_ELEMENT (valve), valve->srcpad);

  valve->sinkpad = gst_pad_new_from_static_template (&sinktemplate, "sink");

  gst_pad_set_chain_function (valve->sinkpad,

      GST_DEBUG_FUNCPTR (gst_valve_chain));

  gst_pad_set_event_function (valve->sinkpad,

      GST_DEBUG_FUNCPTR (gst_valve_sink_event));

  gst_pad_set_query_function (valve->sinkpad,

      GST_DEBUG_FUNCPTR (gst_valve_query));

  GST_PAD_SET_PROXY_CAPS (valve->sinkpad);

  GST_PAD_SET_PROXY_ALLOCATION (valve->sinkpad);

  gst_element_add_pad (GST_ELEMENT (valve), valve->sinkpad);

}

static void

gst_valve_set_property (GObject * object,

    guint prop_id, const GValue * value, GParamSpec * pspec)

{

  GstValve *valve = GST_VALVE (object);

  switch (prop_id) {

    case PROP_DROP:

      g_atomic_int_set (&valve->drop, g_value_get_boolean (value));

      gst_pad_push_event (valve->sinkpad, gst_event_new_reconfigure ());

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

  }

}

static void

gst_valve_get_property (GObject * object,

    guint prop_id, GValue * value, GParamSpec * pspec)

{

  GstValve *valve = GST_VALVE (object);

  switch (prop_id) {

    case PROP_DROP:

      g_value_set_boolean (value, g_atomic_int_get (&valve->drop));

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

  }

}

static gboolean

forward_sticky_events (GstPad * pad, GstEvent ** event, gpointer user_data)

{

  GstValve *valve = user_data;

  if (!gst_pad_push_event (valve->srcpad, gst_event_ref (*event)))

    valve->need_repush_sticky = TRUE;

  return TRUE;

}

static void

gst_valve_repush_sticky (GstValve * valve)

{

  valve->need_repush_sticky = FALSE;

  gst_pad_sticky_events_foreach (valve->sinkpad, forward_sticky_events, valve);

}

static GstFlowReturn

gst_valve_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)

{

  GstValve *valve = GST_VALVE (parent);

  GstFlowReturn ret = GST_FLOW_OK;

  if (g_atomic_int_get (&valve->drop)) {

    gst_buffer_unref (buffer);

    valve->discont = TRUE;

  } else {

    if (valve->discont) {

      buffer = gst_buffer_make_writable (buffer);

      GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);

      valve->discont = FALSE;

    }

    if (valve->need_repush_sticky)

      gst_valve_repush_sticky (valve);

    ret = gst_pad_push (valve->srcpad, buffer);

  }

  /* Ignore errors if "drop" was changed while the thread was blocked

   * downwards

   */

  if (g_atomic_int_get (&valve->drop))

    ret = GST_FLOW_OK;

  return ret;

}

static gboolean

gst_valve_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)

{

  GstValve *valve;

  gboolean is_sticky = GST_EVENT_IS_STICKY (event);

  gboolean ret = TRUE;

  valve = GST_VALVE (parent);

  if (g_atomic_int_get (&valve->drop)) {

    valve->need_repush_sticky |= is_sticky;

    gst_event_unref (event);

  } else {

    if (valve->need_repush_sticky)

      gst_valve_repush_sticky (valve);

    ret = gst_pad_event_default (pad, parent, event);

  }

  /* Ignore errors if "drop" was changed while the thread was blocked

   * downwards.

   */

  if (g_atomic_int_get (&valve->drop)) {

    valve->need_repush_sticky |= is_sticky;

    ret = TRUE;

  }

  return ret;

}

static gboolean

gst_valve_query (GstPad * pad, GstObject * parent, GstQuery * query)

{

  GstValve *valve = GST_VALVE (parent);

  if (GST_QUERY_IS_SERIALIZED (query) && g_atomic_int_get (&valve->drop))

    return FALSE;

  return gst_pad_query_default (pad, parent, query);

}