From 5c763a0a7c5d15a46574efd664431db67750e5c2 Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Sun, 14 Jan 2018 01:03:05 +0100
Subject: Add timeout to zmq2farsync

---
 src/zmq2farsync/zmq2farsync.cpp | 84 ++++++++++++++++++++++++-----------------
 1 file changed, 49 insertions(+), 35 deletions(-)

diff --git a/src/zmq2farsync/zmq2farsync.cpp b/src/zmq2farsync/zmq2farsync.cpp
index 72f4cc3..16830a2 100644
--- a/src/zmq2farsync/zmq2farsync.cpp
+++ b/src/zmq2farsync/zmq2farsync.cpp
@@ -3,7 +3,7 @@
    2011, 2012 Her Majesty the Queen in Right of Canada (Communications
    Research Center Canada)
 
-   Copyright (C) 2015
+   Copyright (C) 2018
    Matthias P. Braendli, matthias.braendli@mpb.li
 
     http://www.opendigitalradio.org
@@ -31,6 +31,9 @@
 #include <iostream>
 #include <vector>
 
+constexpr size_t MAX_ERROR_COUNT = 10;
+constexpr long ZMQ_TIMEOUT_MS = 1000;
+
 void usage(void)
 {
     using namespace std;
@@ -41,7 +44,11 @@ void usage(void)
     cerr << "Where" << endl;
     cerr << " <source> is a ZMQ URL that points to a ODR-DabMux ZMQ output." << endl;
     cerr << " <destination> is the device information for the FarSync card." << endl << endl;
-    cerr << " The syntax is the same as for ODR-DabMux" << endl;
+    cerr << " The syntax is the same as for ODR-DabMux" << endl << endl;
+
+    cerr << "odr-zmq2edi will quit if it does not receive data for " <<
+        (int)(MAX_ERROR_COUNT * ZMQ_TIMEOUT_MS / 1000.0) << " seconds." << endl;
+    cerr << "It is best practice to run this tool under a process supervisor that will restart it automatically." << endl;
 }
 
 int main(int argc, char **argv)
@@ -82,53 +89,60 @@ int main(int argc, char **argv)
     size_t frame_count = 0;
     size_t loop_counter = 0;
     size_t error_count = 0;
-    while (error_count < 10)
+    while (error_count < MAX_ERROR_COUNT)
     {
         zmq::message_t incoming;
-        zmq_sock.recv(&incoming);
-
-        zmq_dab_message_t* dab_msg = (zmq_dab_message_t*)incoming.data();
-
-        if (dab_msg->version != 1) {
-            etiLog.level(error) << "ZeroMQ wrong packet version " << dab_msg->version;
+        zmq::pollitem_t items[1];
+        items[0].socket = zmq_sock;
+        items[0].events = ZMQ_POLLIN;
+        const int num_events = zmq::poll(items, 1, ZMQ_TIMEOUT_MS);
+        if (num_events == 0) { // timeout
             error_count++;
         }
+        else {
+            // Event received: recv will not block
+            zmq_sock.recv(&incoming);
+            zmq_dab_message_t* dab_msg = (zmq_dab_message_t*)incoming.data();
 
-        int offset = sizeof(dab_msg->version) +
-            NUM_FRAMES_PER_ZMQ_MESSAGE * sizeof(*dab_msg->buflen);
-
-        for (int i = 0; i < NUM_FRAMES_PER_ZMQ_MESSAGE; i++) {
-            if (dab_msg->buflen[i] <= 0 ||
-                dab_msg->buflen[i] > 6144)
-            {
-                etiLog.level(error) << "ZeroMQ buffer " << i << " has invalid length " <<
-                    dab_msg->buflen[i];
+            if (dab_msg->version != 1) {
+                etiLog.level(error) << "ZeroMQ wrong packet version " << dab_msg->version;
                 error_count++;
             }
-            else {
-                std::vector<uint8_t> buf(6144, 0x55);
-
-                const int framesize = dab_msg->buflen[i];
-
-                memcpy(&buf.front(),
-                        ((uint8_t*)incoming.data()) + offset,
-                        framesize);
 
-                offset += framesize;
+            int offset = sizeof(dab_msg->version) +
+                NUM_FRAMES_PER_ZMQ_MESSAGE * sizeof(*dab_msg->buflen);
 
-                if (output.Write(&buf.front(), buf.size()) == -1) {
-                    etiLog.level(error) << "Cannot write to output!";
+            for (int i = 0; i < NUM_FRAMES_PER_ZMQ_MESSAGE; i++) {
+                if (dab_msg->buflen[i] <= 0 or dab_msg->buflen[i] > 6144) {
+                    etiLog.level(error) << "ZeroMQ buffer " << i << " has invalid length " <<
+                        dab_msg->buflen[i];
                     error_count++;
                 }
+                else {
+                    std::vector<uint8_t> buf(6144, 0x55);
 
-                frame_count++;
+                    const int framesize = dab_msg->buflen[i];
+
+                    memcpy(&buf.front(),
+                            ((uint8_t*)incoming.data()) + offset,
+                            framesize);
+
+                    offset += framesize;
+
+                    if (output.Write(&buf.front(), buf.size()) == -1) {
+                        etiLog.level(error) << "Cannot write to output!";
+                        error_count++;
+                    }
+
+                    frame_count++;
+                }
             }
-        }
 
-        loop_counter++;
-        if (loop_counter > 250) {
-            etiLog.level(info) << "Transmitted " << frame_count << " ETI frames";
-            loop_counter = 0;
+            loop_counter++;
+            if (loop_counter > 250) {
+                etiLog.level(info) << "Transmitted " << frame_count << " ETI frames";
+                loop_counter = 0;
+            }
         }
     }
 
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