systemclock: Add a test for sync/async clockid interactions

This test randomly hangs if there are problems with the reliability of
unscheduling sync and async clockID's on the system clock.

tests/check/gst/gstsystemclock.c

@@ -279,6 +279,117 @@ GST_START_TEST (test_async_order)
 
 GST_END_TEST;
 
+struct test_async_sync_interaction_data
+{
+  GMutex *lock;
+
+  GstClockID sync_id;
+  GstClockID sync_id2;
+
+  GstClockID async_id;
+  GstClockID async_id2;
+  GstClockID async_id3;
+};
+
+static gboolean
+test_async_sync_interaction_cb (GstClock * clock, GstClockTime time,
+    GstClockID id, gpointer user_data)
+{
+  struct test_async_sync_interaction_data *td =
+      (struct test_async_sync_interaction_data *) (user_data);
+
+  g_mutex_lock (td->lock);
+  /* The first async callback is ignored */
+  if (id == td->async_id)
+    goto out;
+
+  if (id != td->async_id2 && id != td->async_id3)
+    goto out;
+
+  /* Unschedule the sync callback */
+  if (id == td->async_id3) {
+    gst_clock_id_unschedule (td->sync_id);
+    gst_clock_id_unschedule (td->async_id2);
+  }
+out:
+  g_mutex_unlock (td->lock);
+  return FALSE;
+}
+
+GST_START_TEST (test_async_sync_interaction)
+{
+  /* This test schedules an async callback, then before it completes, schedules
+   * an earlier async callback, and quickly unschedules the first, and inserts
+   * a THIRD even earlier async callback. It then attempts to wait on a
+   * sync clock ID. While that's sleeping, the 3rd async callback should fire
+   * and unschedule it. This tests for problems with unscheduling async and
+   * sync callbacks on the system clock. */
+  GstClock *clock;
+  GstClockReturn result;
+  GstClockTime base;
+  GstClockTimeDiff jitter;
+  struct test_async_sync_interaction_data td;
+  int i;
+
+  clock = gst_system_clock_obtain ();
+  fail_unless (clock != NULL, "Could not create instance of GstSystemClock");
+
+  td.lock = g_mutex_new ();
+
+  for (i = 0; i < 50; i++) {
+    gst_clock_debug (clock);
+    base = gst_clock_get_time (clock);
+    g_mutex_lock (td.lock);
+    td.async_id = gst_clock_new_single_shot_id (clock, base + 40 * GST_MSECOND);
+    td.async_id2 =
+        gst_clock_new_single_shot_id (clock, base + 30 * GST_MSECOND);
+    td.async_id3 =
+        gst_clock_new_single_shot_id (clock, base + 20 * GST_MSECOND);
+    td.sync_id2 = gst_clock_new_single_shot_id (clock, base + 10 * GST_MSECOND);
+    td.sync_id = gst_clock_new_single_shot_id (clock, base + 50 * GST_MSECOND);
+    g_mutex_unlock (td.lock);
+
+    result = gst_clock_id_wait_async (td.async_id,
+        test_async_sync_interaction_cb, &td);
+    fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
+
+    /* Wait 10ms, then unschedule async_id and schedule async_id2 */
+    result = gst_clock_id_wait (td.sync_id2, &jitter);
+    fail_unless (result == GST_CLOCK_OK || result == GST_CLOCK_EARLY,
+        "Waiting did not return OK or EARLY");
+    /* async_id2 is earlier than async_id - should become head of the queue */
+    result = gst_clock_id_wait_async (td.async_id2,
+        test_async_sync_interaction_cb, &td);
+    fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
+    gst_clock_id_unschedule (td.async_id);
+
+    /* async_id3 is earlier than async_id2 - should become head of the queue */
+    result = gst_clock_id_wait_async (td.async_id3,
+        test_async_sync_interaction_cb, &td);
+    fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
+
+    /* While this is sleeping, the async3 id should fire and unschedule it */
+    result = gst_clock_id_wait (td.sync_id, &jitter);
+    fail_unless (result == GST_CLOCK_UNSCHEDULED || result == GST_CLOCK_EARLY,
+        "Waiting did not return UNSCHEDULED");
+
+    gst_clock_id_unschedule (td.async_id3);
+    g_mutex_lock (td.lock);
+
+    gst_clock_id_unref (td.sync_id);
+    gst_clock_id_unref (td.sync_id2);
+    gst_clock_id_unref (td.async_id);
+    gst_clock_id_unref (td.async_id2);
+    gst_clock_id_unref (td.async_id3);
+    g_mutex_unlock (td.lock);
+  }
+
+  g_mutex_free (td.lock);
+  gst_object_unref (clock);
+}
+
+GST_END_TEST;
+
 GST_START_TEST (test_periodic_multi)
 {
   GstClock *clock;
@@ -422,6 +533,7 @@ gst_systemclock_suite (void)
   tcase_add_test (tc_chain, test_periodic_shot);
   tcase_add_test (tc_chain, test_periodic_multi);
   tcase_add_test (tc_chain, test_async_order);
+  tcase_add_test (tc_chain, test_async_sync_interaction);
   tcase_add_test (tc_chain, test_diff);
   tcase_add_test (tc_chain, test_mixed);