Support EDI TCP server pre-roll on client connect

Includes common code changes: socket changes for keepalive and preroll

3 files changed, 14 insertions, 6 deletions

diff --git a/lib/edioutput/EDIConfig.h b/lib/edioutput/EDIConfig.h
index d57e9ce..a7225a7 100644
--- a/lib/edioutput/EDIConfig.h
+++ b/lib/edioutput/EDIConfig.h
@@ -74,6 +74,9 @@ struct configuration_t {
     // Spread transmission of fragments in time. 1.0 = 100% means spreading over the whole duration of a frame (24ms)
     // Above 100% means that the fragments are spread over several 24ms periods, interleaving the AF packets.
 
+    // TCP Server output can preroll a fixed number of previous buffers each time a new client connects.
+    size_t tcp_server_preroll_buffers = 0;
+
     bool enabled() const { return destinations.size() > 0; }
 
     void print() const;
diff --git a/lib/edioutput/Transport.cpp b/lib/edioutput/Transport.cpp
index 5d34814..a870aa0 100644
--- a/lib/edioutput/Transport.cpp
+++ b/lib/edioutput/Transport.cpp
@@ -1,5 +1,5 @@
 /*
-   Copyright (C) 2020
+   Copyright (C) 2022
    Matthias P. Braendli, matthias.braendli@mpb.li
 
     http://www.opendigitalradio.org
@@ -66,7 +66,7 @@ Sender::Sender(const configuration_t& conf) :
     edi_pft(m_conf)
 {
     if (m_conf.verbose) {
-        etiLog.log(info, "Setup EDI Output");
+        etiLog.level(info) << "Setup EDI Output, TCP output preroll " << m_conf.tcp_server_preroll_buffers;
     }
 
     for (const auto& edi_dest : m_conf.destinations) {
@@ -81,7 +81,9 @@ Sender::Sender(const configuration_t& conf) :
             udp_sockets.emplace(udp_dest.get(), udp_socket);
         }
         else if (auto tcp_dest = dynamic_pointer_cast<edi::tcp_server_t>(edi_dest)) {
-            auto dispatcher = make_shared<Socket::TCPDataDispatcher>(tcp_dest->max_frames_queued);
+            auto dispatcher = make_shared<Socket::TCPDataDispatcher>(
+                    tcp_dest->max_frames_queued, m_conf.tcp_server_preroll_buffers);
+
             dispatcher->start(tcp_dest->listen_port, "0.0.0.0");
             tcp_dispatchers.emplace(tcp_dest.get(), dispatcher);
         }
@@ -135,9 +137,10 @@ void Sender::write(const AFPacket& af_packet)
         // Apply PFT layer to AF Packet (Reed Solomon FEC and Fragmentation)
         vector<edi::PFTFragment> edi_fragments = edi_pft.Assemble(af_packet);
 
-        if (m_conf.verbose) {
-            fprintf(stderr, "EDI Output: Number of PFT fragments %zu\n",
+        if (m_conf.verbose and m_last_num_pft_fragments != edi_fragments.size()) {
+            etiLog.log(debug, "EDI Output: Number of PFT fragments %zu\n",
                     edi_fragments.size());
+            m_last_num_pft_fragments = edi_fragments.size();
         }
 
         /* Spread out the transmission of all fragments over part of the 24ms AF packet duration
diff --git a/lib/edioutput/Transport.h b/lib/edioutput/Transport.h
index be93297..6a3f229 100644
--- a/lib/edioutput/Transport.h
+++ b/lib/edioutput/Transport.h
@@ -1,5 +1,5 @@
 /*
-   Copyright (C) 2020
+   Copyright (C) 2022
    Matthias P. Braendli, matthias.braendli@mpb.li
 
     http://www.opendigitalradio.org
@@ -90,6 +90,8 @@ class Sender {
         std::mutex m_mutex;
         bool m_running = false;
         std::map<std::chrono::steady_clock::time_point, edi::PFTFragment> m_pending_frames;
+
+        size_t m_last_num_pft_fragments = 0;
 };
 
 }