srtpenc: remove get-rollover-counter signal and add stats property

We remove get-rollover-counter signal in favor of the "stats"
property. The "stats" property is a GstStructure with caps
application/x-srtp-encoder-stats that contains an array of
structures with caps application/x-srtp-stream.
Each stream structure contains "ssrc" and "roc" fields.

https://bugzilla.gnome.org/show_bug.cgi?id=733265

ext/srtp/gstsrtpenc.c

@@ -159,7 +159,8 @@ enum
   PROP_RTCP_AUTH,
   PROP_RANDOM_KEY,
   PROP_REPLAY_WINDOW_SIZE,
-  PROP_ALLOW_REPEAT_TX
+  PROP_ALLOW_REPEAT_TX,
+  PROP_STATS
 };
 
 typedef struct ProcessBufferItData
@@ -246,27 +247,6 @@ static GstPad *gst_srtp_enc_request_new_pad (GstElement * element,
 static void gst_srtp_enc_release_pad (GstElement * element, GstPad * pad);
 
 
-static guint32
-gst_srtp_enc_get_rollover_counter (GstSrtpEnc * filter, guint32 ssrc)
-{
-  guint32 roc = 0;
-  srtp_stream_t stream;
-
-  GST_OBJECT_LOCK (filter);
-
-  GST_DEBUG_OBJECT (filter, "retrieving SRTP Rollover Counter, ssrc: %u", ssrc);
-
-  if (filter->session) {
-    stream = srtp_get_stream (filter->session, htonl (ssrc));
-    if (stream)
-      roc = stream->rtp_rdbx.index >> 16;
-  }
-
-  GST_OBJECT_UNLOCK (filter);
-
-  return roc;
-}
-
 /* initialize the srtpenc's class
  */
 static void
@@ -342,6 +322,9 @@ gst_srtp_enc_class_init (GstSrtpEncClass * klass)
           "(Note that such repeated transmissions must have the same RTP payload, "
           "or a severe security weakness is introduced!)",
           DEFAULT_ALLOW_REPEAT_TX, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class, PROP_STATS,
+      g_param_spec_boxed ("stats", "Statistics", "Various statistics",
+          GST_TYPE_STRUCTURE, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 
   /**
    * GstSrtpEnc::soft-limit:
@@ -354,22 +337,6 @@ gst_srtp_enc_class_init (GstSrtpEncClass * klass)
   gst_srtp_enc_signals[SIGNAL_SOFT_LIMIT] =
       g_signal_new ("soft-limit", G_TYPE_FROM_CLASS (klass),
       G_SIGNAL_RUN_LAST, 0, NULL, NULL, NULL, G_TYPE_NONE, 0);
-
-  /**
-   * GstSrtpEnc::get-rollover-counter:
-   * @gstsrtpenc: the element on which the signal is emitted
-   * @ssrc: The unique SSRC of the stream
-   *
-   * Request the SRTP rollover counter for the stream with @ssrc.
-   */
-  gst_srtp_enc_signals[SIGNAL_GET_ROLLOVER_COUNTER] =
-      g_signal_new ("get-rollover-counter", G_TYPE_FROM_CLASS (klass),
-      G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstSrtpEncClass,
-          get_rollover_counter), NULL, NULL, g_cclosure_marshal_generic,
-      G_TYPE_UINT, 1, G_TYPE_UINT);
-
-  klass->get_rollover_counter =
-      GST_DEBUG_FUNCPTR (gst_srtp_enc_get_rollover_counter);
 }
 
 
@@ -633,6 +600,41 @@ gst_srtp_enc_dispose (GObject * object)
   G_OBJECT_CLASS (gst_srtp_enc_parent_class)->dispose (object);
 }
 
+static GstStructure *
+gst_srtp_enc_create_stats (GstSrtpEnc * filter)
+{
+  GstStructure *s;
+  GValue va = G_VALUE_INIT;
+  GValue v = G_VALUE_INIT;
+
+  s = gst_structure_new_empty ("application/x-srtp-encoder-stats");
+
+  g_value_init (&va, GST_TYPE_ARRAY);
+  g_value_init (&v, GST_TYPE_STRUCTURE);
+
+  if (filter->session) {
+    srtp_stream_t stream = filter->session->stream_list;
+    while (stream) {
+      GstStructure *ss;
+      guint32 ssrc = GUINT32_FROM_BE (stream->ssrc);
+      guint32 roc = stream->rtp_rdbx.index >> 16;
+
+      ss = gst_structure_new ("application/x-srtp-stream",
+          "ssrc", G_TYPE_UINT, ssrc, "roc", G_TYPE_UINT, roc, NULL);
+
+      g_value_take_boxed (&v, ss);
+      gst_value_array_append_value (&va, &v);
+
+      stream = stream->next;
+    }
+  }
+
+  gst_structure_take_value (s, "streams", &va);
+  g_value_unset (&v);
+
+  return s;
+}
+
 static void
 gst_srtp_enc_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
@@ -724,6 +726,9 @@ gst_srtp_enc_get_property (GObject * object, guint prop_id,
     case PROP_ALLOW_REPEAT_TX:
       g_value_set_boolean (value, filter->allow_repeat_tx);
       break;
+    case PROP_STATS:
+      g_value_take_boxed (value, gst_srtp_enc_create_stats (filter));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;

ext/srtp/gstsrtpenc.h

@@ -89,9 +89,6 @@ struct _GstSrtpEnc
 struct _GstSrtpEncClass
 {
   GstElementClass parent_class;
-
-  /* action signals */
-  guint32 (*get_rollover_counter) (GstSrtpEnc *encoder, guint32 ssrc);
 };
 
 GType gst_srtp_enc_get_type (void);