Add support and test for concurrent TransitionTo

fairmq/FairMQDevice.cxx

@@ -106,6 +106,11 @@ FairMQDevice::FairMQDevice(ProgOptions* config, const tools::Version version)
     , fMaxRunRuntimeInS(DefaultMaxRunTime)
     , fInitializationTimeoutInS(DefaultInitTimeout)
     , fRawCmdLineArgs()
+    , fStates()
+    , fStatesMtx()
+    , fStatesCV()
+    , fTransitionMtx()
+    , fTransitioning(false)
 {
     SubscribeToNewTransition("device", [&](Transition transition) {
         LOG(trace) << "device notified on new transition: " << transition;
@@ -187,6 +192,15 @@ void FairMQDevice::WaitForState(fair::mq::State state)
 
 void FairMQDevice::TransitionTo(const fair::mq::State s)
 {
+    {
+        lock_guard<mutex> lock(fTransitionMtx);
+        if (fTransitioning) {
+            LOG(debug) << "Attempting a transition with TransitionTo() while another one is already in progress";
+            throw OngoingTransition("Attempting a transition with TransitionTo() while another one is already in progress");
+        }
+        fTransitioning = true;
+    }
+
     using fair::mq::State;
     State currentState = GetCurrentState();
 
@@ -225,6 +239,11 @@ void FairMQDevice::TransitionTo(const fair::mq::State s)
 
         currentState = WaitForNextState();
     }
+
+    {
+        lock_guard<mutex> lock(fTransitionMtx);
+        fTransitioning = false;
+    }
 }
 
 bool FairMQDevice::ChangeState(const int transition)

fairmq/FairMQDevice.h

@@ -44,6 +44,14 @@ using FairMQChannelMap = std::unordered_map<std::string, std::vector<FairMQChann
 using InputMsgCallback = std::function<bool(FairMQMessagePtr&, int)>;
 using InputMultipartCallback = std::function<bool(FairMQParts&, int)>;
 
+namespace fair
+{
+namespace mq
+{
+struct OngoingTransition : std::runtime_error { using std::runtime_error::runtime_error; };
+}
+}
+
 class FairMQDevice
 {
     friend class FairMQChannel;
@@ -584,6 +592,9 @@ class FairMQDevice
     std::queue<fair::mq::State> fStates;
     std::mutex fStatesMtx;
     std::condition_variable fStatesCV;
+
+    std::mutex fTransitionMtx;
+    bool fTransitioning;
 };
 
 #endif /* FAIRMQDEVICE_H_ */