[gst-devel] Possible bug with base sink and preroll length of > 0

[Will Newton]

Hi all,

I've been having a little trouble with a deadlock happening when I
change the state of a pipeline with a sink with a preroll queue length
of > 0.

I have attached a modified version of the stress.c test that seems to
show the problem at least for me. With my custom sink I have also had
it happening with a 0 preroll queue length but the debug looks
substantially similar in this case.

The "fix" I am using is to inspect the return code of
gst_base_sink_render_object() at line 1740 of gstbasesink.c and exit
if it's not GST_FLOW_OK. I'm not sure if that's a correct solution
though.
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/* GStreamer
 * Copyright (C) 2005 Andy Wingo <wingo at pobox.com>
 *
 * 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.
 */


#include <gst/check/gstcheck.h>

static GstElement *pipeline;
static int playing = 1;
static int quit = 0;

gboolean change_state_timeout(gpointer data)
{
  if (quit)
    return FALSE;

  if (playing) {
    playing = 0;
    gst_element_set_state (pipeline, GST_STATE_NULL);
  }
  else {    
    playing = 1;
    gst_element_set_state (pipeline, GST_STATE_PLAYING);
  }

  return TRUE;
}

gboolean quit_timeout(gpointer data)
{
  quit = 1;
  return FALSE;
}

GST_START_TEST (test_stress)
{
  GstElement *fakesrc, *fakesink;
  gint i;

  fakesrc = gst_element_factory_make ("fakesrc", NULL);
  fakesink = gst_element_factory_make ("fakesink", NULL);
  pipeline = gst_element_factory_make ("pipeline", NULL);

  g_return_if_fail (fakesrc && fakesink && pipeline);

  g_object_set(G_OBJECT(fakesink), "preroll-queue-len", 4, NULL);

  gst_bin_add_many (GST_BIN (pipeline), fakesrc, fakesink, NULL);
  gst_element_link (fakesrc, fakesink);

  gst_element_set_state (pipeline, GST_STATE_PLAYING);

  g_timeout_add(500, &change_state_timeout, NULL);
  g_timeout_add(10000, &quit_timeout, NULL);

  gst_debug_set_default_threshold(GST_LEVEL_DEBUG);

  while (!quit) {
    g_main_context_iteration(NULL, TRUE);
  }

  gst_object_unref (pipeline);
}

GST_END_TEST;


Suite *
stress_suite (void)
{
  Suite *s = suite_create ("stress");
  TCase *tc_chain = tcase_create ("linear");

  /* time out after 20s, not the default 3 */
  tcase_set_timeout (tc_chain, 0);

  suite_add_tcase (s, tc_chain);
  tcase_add_test (tc_chain, test_stress);
  return s;
}

GST_CHECK_MAIN (stress);