From e8c274301aca0bca1b7d1e6086cf29af4645732e Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Fri, 21 Feb 2014 10:49:42 +0100
Subject: zmq input improvements

---
 src/InputReader.h         |  5 ++---
 src/InputZeroMQReader.cpp | 27 +++++++++++++++++++++++----
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/src/InputReader.h b/src/InputReader.h
index ae36899..de8fb78 100644
--- a/src/InputReader.h
+++ b/src/InputReader.h
@@ -143,15 +143,14 @@ class InputZeroMQWorker
 {
     public:
         InputZeroMQWorker() :
-            zmqcontext(1), subscriber(zmqcontext, ZMQ_SUB) {}
+            zmqcontext(1)  {}
 
         void Start(struct InputZeroMQThreadData* workerdata);
         void Stop();
     private:
         void RecvProcess(struct InputZeroMQThreadData* workerdata);
         bool running;
-        zmq::context_t zmqcontext;
-        zmq::socket_t subscriber;
+        zmq::context_t zmqcontext; // is thread-safe
         boost::thread recv_thread;
 };
 
diff --git a/src/InputZeroMQReader.cpp b/src/InputZeroMQReader.cpp
index 6b81ec2..4b55434 100644
--- a/src/InputZeroMQReader.cpp
+++ b/src/InputZeroMQReader.cpp
@@ -88,6 +88,12 @@ void InputZeroMQWorker::RecvProcess(struct InputZeroMQThreadData* workerdata)
 {
     size_t queue_size = 0;
 
+    bool buffer_full = false;
+
+    zmq::socket_t subscriber(zmqcontext, ZMQ_SUB);
+    // zmq sockets are not thread safe. That's why
+    // we create it here, and not at object creation.
+
     try {
         subscriber.connect(workerdata->uri.c_str());
 
@@ -99,24 +105,37 @@ void InputZeroMQWorker::RecvProcess(struct InputZeroMQThreadData* workerdata)
             subscriber.recv(&incoming);
 
             if (queue_size < MAX_QUEUE_SIZE) {
+                if (buffer_full) {
+                    fprintf(stderr, "ZeroMQ buffer recovered: %zu elements\n",
+                            queue_size);
+                    buffer_full = false;
+                }
+
                 zmq::message_t* holder = new zmq::message_t();
                 holder->move(&incoming); // move the message into the holder
                 queue_size = workerdata->in_messages->push(holder);
             }
             else
             {
-                workerdata->in_messages->notify();
-                fprintf(stderr, "ZeroMQ message overfull: %zu elements !\n", queue_size);
+                if (!buffer_full) {
+                    workerdata->in_messages->notify();
+                    fprintf(stderr, "ZeroMQ buffer overfull !\n");
+
+                    buffer_full = true;
+                }
             }
 
             if (queue_size < 5) {
-                fprintf(stderr, "ZeroMQ message underfull: %zu elements !\n", queue_size);
+                fprintf(stderr, "ZeroMQ buffer underfull: %zu elements !\n",
+                        queue_size);
             }
         }
     }
     catch (zmq::error_t& err) {
         printf("ZeroMQ error in RecvProcess: '%s'\n", err.what());
     }
+
+    subscriber.close();
 }
 
 void InputZeroMQWorker::Start(struct InputZeroMQThreadData* workerdata)
@@ -127,8 +146,8 @@ void InputZeroMQWorker::Start(struct InputZeroMQThreadData* workerdata)
 
 void InputZeroMQWorker::Stop()
 {
-    subscriber.close();
     running = false;
+    recv_thread.join();
 }
 
 #endif
-- 
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