clockselect: Add TAI clock support

Via new value for property clock-id, "tai", it's possible to use
GST_CLOCK_TYPE_TAI as pipeline clock.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1009>

gst/debugutils/gstclockselect.c

@@ -56,6 +56,7 @@ gst_clock_select_clock_id_get_type (void)
         "monotonic"},
     {GST_CLOCK_SELECT_CLOCK_ID_REALTIME, "System realtime clock", "realtime"},
     {GST_CLOCK_SELECT_CLOCK_ID_PTP, "PTP clock", "ptp"},
+    {GST_CLOCK_SELECT_CLOCK_ID_TAI, "System TAI clock", "tai"},
     {0, NULL, NULL},
   };
 
@@ -195,6 +196,13 @@ gst_clock_select_provide_clock (GstElement * element)
             "Failed to get PTP clock, falling back to pipeline default clock");
       }
       break;
+    case GST_CLOCK_SELECT_CLOCK_ID_TAI:
+      clock =
+          g_object_new (GST_TYPE_SYSTEM_CLOCK, "name", "DebugGstSystemClock",
+          NULL);
+      gst_object_ref_sink (clock);
+      gst_util_set_object_arg (G_OBJECT (clock), "clock-type", "tai");
+      break;
     case GST_CLOCK_SELECT_CLOCK_ID_DEFAULT:
     default:
       clock = NULL;

gst/debugutils/gstclockselect.h

@@ -39,6 +39,7 @@ enum _GstClockSelectClockId {
   GST_CLOCK_SELECT_CLOCK_ID_MONOTONIC,
   GST_CLOCK_SELECT_CLOCK_ID_REALTIME,
   GST_CLOCK_SELECT_CLOCK_ID_PTP,
+  GST_CLOCK_SELECT_CLOCK_ID_TAI,
 };
 
 struct _GstClockSelect

tests/check/elements/clockselect.c

@@ -22,6 +22,30 @@
 #include <gst/check/gstcheck.h>
 #include <gst/check/gstharness.h>
 
+GST_START_TEST (test_clock_select_tai_clock)
+{
+  GstHarness *h;
+  GstElement *element;
+  GstClock *clock;
+  guint clock_type;
+
+  h = gst_harness_new_parse ("clockselect clock-id=tai");
+
+  /* Check if element provides right clock */
+  element = gst_harness_find_element (h, "clockselect");
+  clock = gst_element_provide_clock (element);
+
+  fail_unless (GST_IS_SYSTEM_CLOCK (clock));
+  g_object_get (G_OBJECT (clock), "clock-type", &clock_type, NULL);
+  fail_unless_equals_uint64 (clock_type, GST_CLOCK_TYPE_TAI);
+
+  gst_object_unref (element);
+  gst_object_unref (clock);
+  gst_harness_teardown (h);
+}
+
+GST_END_TEST;
+
 GST_START_TEST (test_clock_select_realtime_clock)
 {
   GstHarness *h;
@@ -102,6 +126,7 @@ clock_select_suite (void)
   tcase_add_test (tc_chain, test_clock_select_properties);
   tcase_add_test (tc_chain, test_clock_select_monotonic_clock);
   tcase_add_test (tc_chain, test_clock_select_realtime_clock);
+  tcase_add_test (tc_chain, test_clock_select_tai_clock);
 
   return s;
 }