path: root/ext/gconf/gstswitchsink.c

/* GStreamer
 * Copyright (c) 2005 Ronald S. Bultje <rbultje@ronald.bitfreak.net>
 * Copyright (c) 2006 Jürg Billeter <j@bitron.ch>
 * Copyright (c) 2007 Jan Schmidt <thaytan@noraisin.net>
 * Copyright (c) 2010 Sebastian Dröge <sebastian.droege@collabora.co.uk>
 *
 * 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

#include <string.h>

#include "gstswitchsink.h"

GST_DEBUG_CATEGORY_STATIC (switch_debug);
#define GST_CAT_DEFAULT switch_debug

static void gst_switch_sink_dispose (GObject * object);
static GstStateChangeReturn
gst_switch_sink_change_state (GstElement * element, GstStateChange transition);
static gboolean gst_switch_sink_commit_new_kid (GstSwitchSink * sink);

static gboolean gst_switch_sink_event (GstPad * pad, GstEvent * event);
static GstFlowReturn gst_switch_sink_bufferalloc (GstPad * pad, guint64 offset,
    guint size, GstCaps * caps, GstBuffer ** buf);

GST_BOILERPLATE (GstSwitchSink, gst_switch_sink, GstBin, GST_TYPE_BIN);

static void
gst_switch_sink_base_init (gpointer klass)
{
  GST_DEBUG_CATEGORY_INIT (switch_debug, "switchsink", 0, "switchsink element");
}

static void
gst_switch_sink_class_init (GstSwitchSinkClass * klass)
{
  GObjectClass *oklass = G_OBJECT_CLASS (klass);
  GstElementClass *eklass = GST_ELEMENT_CLASS (klass);
  static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
      GST_PAD_SINK,
      GST_PAD_ALWAYS,
      GST_STATIC_CAPS_ANY);
  GstPadTemplate *child_pad_templ;

  oklass->dispose = gst_switch_sink_dispose;
  eklass->change_state = gst_switch_sink_change_state;

  /* Provide a default pad template if the child didn't */
  child_pad_templ = gst_element_class_get_pad_template (eklass, "sink");
  if (child_pad_templ == NULL) {
    gst_element_class_add_pad_template (eklass,
        gst_static_pad_template_get (&sink_template));
  }
}

static gboolean
gst_switch_sink_reset (GstSwitchSink * sink)
{
  if (sink->blocking) {
    gst_pad_set_blocked (sink->pad, FALSE);
    sink->blocking = FALSE;
  }

  /* this will install fakesink if no other child has been set,
   * otherwise we rely on the subclass to know when to unset its
   * custom kid */
  if (sink->kid == NULL) {
    return gst_switch_sink_set_child (sink, NULL);
  }

  return TRUE;
}

static void
gst_switch_sink_init (GstSwitchSink * sink, GstSwitchSinkClass * g_class)
{
  GstElementClass *eklass = GST_ELEMENT_GET_CLASS (sink);
  GstPadTemplate *templ;

  templ = gst_element_class_get_pad_template (eklass, "sink");
  sink->pad = gst_ghost_pad_new_no_target_from_template ("sink", templ);
  sink->ghostpad_event_func = GST_PAD_EVENTFUNC (sink->pad);
  gst_pad_set_event_function (sink->pad,
      GST_DEBUG_FUNCPTR (gst_switch_sink_event));
  sink->ghostpad_bufferalloc_func = GST_PAD_BUFFERALLOCFUNC (sink->pad);
  gst_pad_set_bufferalloc_function (sink->pad,
      GST_DEBUG_FUNCPTR (gst_switch_sink_bufferalloc));
  gst_element_add_pad (GST_ELEMENT (sink), sink->pad);

  gst_switch_sink_reset (sink);

  GST_OBJECT_FLAG_SET (sink, GST_ELEMENT_IS_SINK);
}

static void
gst_switch_sink_dispose (GObject * object)
{
  GstSwitchSink *sink = GST_SWITCH_SINK (object);
  GstObject *new_kid, *kid;

  GST_OBJECT_LOCK (sink);
  new_kid = GST_OBJECT_CAST (sink->new_kid);
  sink->new_kid = NULL;

  kid = GST_OBJECT_CAST (sink->kid);
  sink->kid = NULL;
  GST_OBJECT_UNLOCK (sink);

  gst_object_replace (&new_kid, NULL);
  gst_object_replace (&kid, NULL);

  GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
}

static void
gst_switch_sink_reset_old_kids (GstElement * old_kid, GstSwitchSink * sink)
{
  GST_DEBUG_OBJECT (sink, "Resetting old kid: %s", GST_ELEMENT_NAME (old_kid));
  gst_element_set_state (old_kid, GST_STATE_NULL);
  gst_object_unref (old_kid);
}

static void
gst_switch_sink_pad_blocked (GstPad * pad, gboolean blocked,
    GstSwitchSink * sink)
{
  if (!blocked) {
    GST_DEBUG_OBJECT (sink, "Unblocked pad");
    sink->blocking = FALSE;
    return;
  }

  sink->blocking = TRUE;

  GST_DEBUG_OBJECT (sink, "Blocked pad");
  gst_switch_sink_commit_new_kid (sink);
}

static gboolean
gst_switch_sink_commit_new_kid (GstSwitchSink * sink)
{
  GstPad *targetpad;
  GstState kid_state;
  GstElement *new_kid, *old_kid;
  gboolean is_fakesink = FALSE;
  GstBus *bus;

  /* need locking around member accesses */
  GST_OBJECT_LOCK (sink);
  /* If we're currently changing state, set the child to the next state
   * we're transitioning too, rather than our current state which is 
   * about to change */
  if (GST_STATE_NEXT (sink) != GST_STATE_VOID_PENDING)
    kid_state = GST_STATE_NEXT (sink);
  else
    kid_state = GST_STATE (sink);

  new_kid = sink->new_kid ? gst_object_ref (sink->new_kid) : NULL;
  sink->new_kid = NULL;
  GST_OBJECT_UNLOCK (sink);

  /* Fakesink by default if NULL is passed as the new child */
  if (new_kid == NULL) {
    GST_DEBUG_OBJECT (sink, "Replacing kid with fakesink");
    new_kid = gst_element_factory_make ("fakesink", "testsink");
    if (new_kid == NULL) {
      GST_ERROR_OBJECT (sink, "Failed to create fakesink");
      return FALSE;
    }
    /* Add a reference, as it would if the element came from sink->new_kid */
    gst_object_ref (new_kid);
    g_object_set (new_kid, "sync", TRUE, NULL);
    is_fakesink = TRUE;
  } else {
    GST_DEBUG_OBJECT (sink, "Setting new kid");
  }

  /* set temporary bus of our own to catch error messages from the child
   * (could we just set our own bus on it, or would the state change messages
   * from the not-yet-added element confuse the state change algorithm? Let's
   * play it safe for now) */
  bus = gst_bus_new ();
  gst_element_set_bus (new_kid, bus);
  gst_object_unref (bus);

  if (gst_element_set_state (new_kid,
          GST_STATE_READY) == GST_STATE_CHANGE_FAILURE) {
    GstMessage *msg;

    /* check if child posted an error message and if so re-post it on our bus
     * so that the application gets to see a decent error and not our generic
     * fallback error message which is completely indecipherable to the user */
    msg = gst_bus_pop_filtered (GST_ELEMENT_BUS (new_kid), GST_MESSAGE_ERROR);
    if (msg) {
      GST_INFO_OBJECT (sink, "Forwarding kid error: %" GST_PTR_FORMAT, msg);
      gst_element_post_message (GST_ELEMENT (sink), msg);
    }
    GST_ELEMENT_ERROR (sink, CORE, STATE_CHANGE, (NULL),
        ("Failed to set state on new child."));
    gst_element_set_bus (new_kid, NULL);
    gst_object_unref (new_kid);
    return FALSE;
  }
  gst_element_set_bus (new_kid, NULL);
  gst_bin_add (GST_BIN (sink), new_kid);

  /* Now, replace the existing child */
  GST_OBJECT_LOCK (sink);
  old_kid = sink->kid;
  sink->kid = new_kid;
  /* Mark whether a custom kid or fakesink has been installed */
  sink->have_kid = !is_fakesink;
  GST_OBJECT_UNLOCK (sink);

  /* kill old element */
  if (old_kid) {
    GST_DEBUG_OBJECT (sink, "Removing old kid %" GST_PTR_FORMAT, old_kid);
    gst_bin_remove (GST_BIN (sink), old_kid);
    /* Don't lose the SINK flag */
    GST_OBJECT_FLAG_SET (sink, GST_ELEMENT_IS_SINK);

    if (!sink->blocking) {
      gst_element_set_state (old_kid, GST_STATE_NULL);
      gst_object_unref (old_kid);
    } else {
      g_thread_pool_push (sink->thread_pool, old_kid, NULL);
    }
  }

  /* re-attach ghostpad */
  GST_DEBUG_OBJECT (sink, "Creating new ghostpad");
  targetpad = gst_element_get_static_pad (sink->kid, "sink");
  gst_ghost_pad_set_target (GST_GHOST_PAD (sink->pad), targetpad);
  gst_object_unref (targetpad);
  GST_DEBUG_OBJECT (sink, "done changing child of switchsink");

  if (gst_element_set_state (new_kid, kid_state) == GST_STATE_CHANGE_FAILURE) {
    GST_ELEMENT_ERROR (sink, CORE, STATE_CHANGE, (NULL),
        ("Failed to set state on new child."));
    GST_OBJECT_LOCK (sink);
    gst_object_unref (sink->kid);
    sink->kid = NULL;
    GST_OBJECT_UNLOCK (sink);
    return FALSE;
  }

  if (sink->segment.format != GST_FORMAT_UNDEFINED) {
    GstEvent *event;
    GstSegment *segment = &sink->segment;

    event = gst_event_new_new_segment_full (FALSE, segment->rate,
        segment->applied_rate, segment->format, 0, segment->accum, 0);

    gst_pad_send_event (sink->pad, event);

    event = gst_event_new_new_segment_full (FALSE, segment->rate,
        segment->applied_rate, segment->format,
        segment->start, segment->stop, segment->time);

    gst_pad_send_event (sink->pad, event);
  }

  /* Unblock the target pad if necessary */
  if (sink->blocking) {
    gst_pad_set_blocked_async_full (sink->pad, FALSE,
        (GstPadBlockCallback) gst_switch_sink_pad_blocked,
        gst_object_ref (sink), (GDestroyNotify) gst_object_unref);
  }

  return TRUE;
}

gboolean
gst_switch_sink_set_child (GstSwitchSink * sink, GstElement * new_kid)
{
  GstState cur, next;
  GstElement **p_kid;

  /* Nothing to do if clearing the child and we've already installed fakesink */
  if (new_kid == NULL && sink->kid != NULL && sink->have_kid == FALSE)
    return TRUE;

  /* Store the new kid to be committed later */
  GST_OBJECT_LOCK (sink);
  cur = GST_STATE (sink);
  next = GST_STATE_NEXT (sink);
  p_kid = &sink->new_kid;
  gst_object_replace ((GstObject **) p_kid, (GstObject *) new_kid);
  GST_OBJECT_UNLOCK (sink);
  if (new_kid)
    gst_object_unref (new_kid);

  if (cur > GST_STATE_READY || next == GST_STATE_PAUSED) {
    GST_DEBUG_OBJECT (sink, "Already running, switching child after pad-block");
    if (!sink->blocking) {
      sink->blocking = TRUE;
      gst_pad_set_blocked_async_full (sink->pad, TRUE,
          (GstPadBlockCallback) gst_switch_sink_pad_blocked,
          gst_object_ref (sink), (GDestroyNotify) gst_object_unref);
    }
    return TRUE;
  }

  return gst_switch_sink_commit_new_kid (sink);
}

static GstStateChangeReturn
gst_switch_sink_change_state (GstElement * element, GstStateChange transition)
{
  GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
  GstSwitchSink *sink = GST_SWITCH_SINK (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      sink->thread_pool =
          g_thread_pool_new ((GFunc) gst_switch_sink_reset_old_kids, sink, 1,
          FALSE, NULL);
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      gst_segment_init (&sink->segment, GST_FORMAT_UNDEFINED);
      break;
    default:
      break;
  }

  ret = GST_CALL_PARENT_WITH_DEFAULT (GST_ELEMENT_CLASS, change_state,
      (element, transition), GST_STATE_CHANGE_SUCCESS);

  switch (transition) {
    case GST_STATE_CHANGE_READY_TO_NULL:
      if (!gst_switch_sink_reset (sink))
        ret = GST_STATE_CHANGE_FAILURE;

      if (sink->thread_pool) {
        g_thread_pool_free (sink->thread_pool, FALSE, TRUE);
        sink->thread_pool = NULL;
      }
      break;
    default:
      break;
  }

  return ret;
}

static gboolean
gst_switch_sink_event (GstPad * pad, GstEvent * event)
{
  GstSwitchSink *sink = GST_SWITCH_SINK (gst_pad_get_parent (pad));
  gboolean ret;

  if (GST_EVENT_TYPE (event) == GST_EVENT_FLUSH_STOP) {
    GST_DEBUG_OBJECT (sink, "Resetting segment because of flush-stop event");
    gst_segment_init (&sink->segment, GST_FORMAT_UNDEFINED);
  }

  ret = sink->ghostpad_event_func (pad, gst_event_ref (event));

  if (GST_EVENT_TYPE (event) == GST_EVENT_NEWSEGMENT) {
    gboolean update;
    gdouble rate, applied_rate;
    GstFormat format;
    gint64 start, stop, position;

    GST_DEBUG_OBJECT (sink, "Newsegment event: %" GST_PTR_FORMAT,
        event->structure);
    gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
        &format, &start, &stop, &position);

    if (sink->segment.format != GST_FORMAT_UNDEFINED
        && format != sink->segment.format) {
      GST_ERROR_OBJECT (sink,
          "Newsegment event in different format: %s (expected %s)",
          gst_format_get_name (format),
          gst_format_get_name (sink->segment.format));
      gst_object_unref (event);
      gst_object_unref (sink);
      return FALSE;
    }

    GST_DEBUG_OBJECT (pad, "Old segment: %" GST_SEGMENT_FORMAT, &sink->segment);
    gst_segment_set_newsegment_full (&sink->segment, update, rate,
        applied_rate, format, start, stop, position);
    GST_DEBUG_OBJECT (sink, "New video segment: %" GST_SEGMENT_FORMAT,
        &sink->segment);
  }

  gst_event_unref (event);
  gst_object_unref (sink);

  return ret;
}

static GstFlowReturn
gst_switch_sink_bufferalloc (GstPad * pad, guint64 offset, guint size,
    GstCaps * caps, GstBuffer ** buf)
{
  GstSwitchSink *sink = GST_SWITCH_SINK (gst_pad_get_parent (pad));
  GstFlowReturn ret;
  GstPad *target;

  target = gst_ghost_pad_get_target (GST_GHOST_PAD_CAST (pad));
  if (target) {
    if (GST_PAD_CAPS (target) != caps
        && !gst_caps_is_equal (caps, GST_PAD_CAPS (target))) {
      GST_DEBUG_OBJECT (sink,
          "Have new caps: %" GST_PTR_FORMAT " -> %" GST_PTR_FORMAT,
          GST_PAD_CAPS (target), caps);

      if (!gst_pad_accept_caps (target, caps)) {
        GST_DEBUG_OBJECT (sink,
            "New target did not accept caps, trying to get possible caps");
        caps = gst_pad_get_caps (target);

        if (caps) {
          GST_DEBUG_OBJECT (sink, "Sink has caps %" GST_PTR_FORMAT, caps);
          if (!gst_caps_is_fixed (caps)) {
            gst_caps_truncate (caps);
            gst_pad_fixate_caps (target, caps);

            if (!gst_caps_is_fixed (caps)) {
              GST_ERROR_OBJECT (sink, "Unable to fixate caps");
              gst_caps_unref (caps);
              ret = GST_FLOW_NOT_NEGOTIATED;
              *buf = NULL;
              goto done;
            }

            GST_DEBUG_OBJECT (sink, "Caps fixated to %" GST_PTR_FORMAT, caps);
          }

          ret = GST_FLOW_OK;
          *buf = gst_buffer_new ();
          gst_buffer_set_caps (*buf, caps);
          gst_caps_unref (caps);
        }

        if (!*buf)
          ret = GST_FLOW_NOT_NEGOTIATED;
        goto done;
      }
    }
    gst_object_unref (target);
  }

  ret = sink->ghostpad_bufferalloc_func (pad, offset, size, caps, buf);

done:
  gst_object_unref (sink);
  return ret;
}