RTC: Refine static cast for RTC connection

trunk/src/app/srs_app_rtc_conn.hpp

@@ -415,8 +415,11 @@ public:
 };
 
 // A RTC Peer Connection, SDP level object.
-class SrsRtcConnection : virtual public ISrsHourGlass, virtual public ISrsResource
-    , virtual public ISrsDisposingHandler
+//
+// For performance, we use non-virtual public from resource,
+// see https://stackoverflow.com/questions/3747066/c-cannot-convert-from-base-a-to-derived-type-b-via-virtual-base-a
+class SrsRtcConnection : public ISrsResource
+    , virtual public ISrsHourGlass, virtual public ISrsDisposingHandler
 {
     friend class SrsSecurityTransport;
     friend class SrsRtcPlayStream;

trunk/src/app/srs_app_rtc_server.cpp

@@ -303,18 +303,12 @@ srs_error_t SrsRtcServer::on_udp_packet(SrsUdpMuxSocket* skt)
     string peer_id = skt->peer_id();
     char* data = skt->data(); int size = skt->size();
 
-    SrsRtcConnection* session = NULL;
-    if (true) {
-        ISrsResource* conn = _srs_rtc_manager->find_by_id(peer_id);
-        if (conn) {
+    SrsRtcConnection* session = (SrsRtcConnection*)_srs_rtc_manager->find_by_id(peer_id);
+    if (session) {
         // Switch to the session to write logs to the context.
-            session = dynamic_cast<SrsRtcConnection*>(conn);
         session->switch_to_context();
-        }
-    }
 
         // When got any packet, the session is alive now.
-    if (session) {
         session->alive();
     }