fix(control): Honor SIGINT and SIGTERM in more places

* Queue next transition for long-running states (fix #421)
* Add *OrCustom/Push/Locked family of functions to StateQueue to enable
  composition with custom signals

fairmq/StateQueue.h

@@ -1,5 +1,5 @@
 /********************************************************************************
- *    Copyright (C) 2019 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ * Copyright (C) 2019-2022 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH  *
  *                                                                              *
  *              This software is distributed under the terms of the             *
  *              GNU Lesser General Public Licence (LGPL) version 3,             *
@@ -9,16 +9,14 @@
 #ifndef FAIRMQSTATEQUEUE_H_
 #define FAIRMQSTATEQUEUE_H_
 
-#include <fairmq/States.h>
-
-#include <queue>
-#include <mutex>
 #include <chrono>
-#include <utility> // pair
 #include <condition_variable>
+#include <fairmq/States.h>
+#include <mutex>
+#include <queue>
+#include <utility>   // pair
 
-namespace fair::mq
-{
+namespace fair::mq {
 
 class StateQueue
 {
@@ -33,41 +31,47 @@ class StateQueue
     fair::mq::State WaitForNext()
     {
         std::unique_lock<std::mutex> lock(fMtx);
-        while (fStates.empty()) {
-            fCV.wait_for(lock, std::chrono::milliseconds(50));
-        }
-
-        fair::mq::State state = fStates.front();
-
-        if (state == fair::mq::State::Error) {
-            throw DeviceErrorState("Controlled device transitioned to error state.");
-        }
-
-        fStates.pop();
-        return state;
+        fCV.wait(lock, [this] { return Predicate(); });
+        return PopFrontUnsafe();
     }
 
-    template<typename Rep, typename Period>
-    std::pair<bool, fair::mq::State> WaitForNext(std::chrono::duration<Rep, Period> const& duration)
+    template<typename Timeout>
+    std::pair<bool, fair::mq::State> WaitForNext(Timeout&& duration)
     {
         std::unique_lock<std::mutex> lock(fMtx);
-        fCV.wait_for(lock, duration);
-
-        if (fStates.empty()) {
-            return { false, fair::mq::State::Ok };
-        }
-
-        fair::mq::State state = fStates.front();
-
-        if (state == fair::mq::State::Error) {
-            throw DeviceErrorState("Controlled device transitioned to error state.");
-        }
-
-        fStates.pop();
-        return { true, state };
+        fCV.wait_for(lock, std::forward<Timeout>(duration), [this] { return Predicate(); });
+        return ReturnPairUnsafe();
     }
 
-    void WaitForState(fair::mq::State state) { while (WaitForNext() != state) {} }
+    template<typename CustomPredicate>
+    std::pair<bool, fair::mq::State> WaitForNextOrCustom(CustomPredicate&& customPredicate)
+    {
+        std::unique_lock<std::mutex> lock(fMtx);
+        fCV.wait(lock, [this, cp = std::move(customPredicate)] { return Predicate() || cp(); });
+        return ReturnPairUnsafe();
+    }
+
+    template<typename CustomPredicate>
+    std::pair<bool, fair::mq::State> WaitForCustom(CustomPredicate&& customPredicate)
+    {
+        std::unique_lock<std::mutex> lock(fMtx);
+        fCV.wait(lock, [cp = std::move(customPredicate)] { return cp(); });
+        return ReturnPairUnsafe();
+    }
+
+    void WaitForState(fair::mq::State state)
+    {
+        while (WaitForNext() != state) {}
+    }
+
+    template<typename CustomPredicate>
+    void WaitForStateOrCustom(fair::mq::State state, CustomPredicate customPredicate)
+    {
+        auto next = WaitForNextOrCustom(customPredicate);
+        while (!customPredicate() && (next.first && next.second != state)) {
+            next = WaitForNextOrCustom(customPredicate);
+        }
+    }
 
     void Push(fair::mq::State state)
     {
@@ -75,7 +79,35 @@ class StateQueue
             std::lock_guard<std::mutex> lock(fMtx);
             fStates.push(state);
         }
-        fCV.notify_all();
+        fCV.notify_one();
+    }
+
+    template<typename CustomSignal>
+    void Push(fair::mq::State state, CustomSignal&& signal)
+    {
+        {
+            std::lock_guard<std::mutex> lock(fMtx);
+            fStates.push(state);
+            signal();
+        }
+        fCV.notify_one();
+    }
+
+    template<typename CustomSignal>
+    void Notify(CustomSignal&& signal)
+    {
+        {
+            std::lock_guard<std::mutex> lock(fMtx);
+            signal();
+        }
+        fCV.notify_one();
+    }
+
+    template<typename CustomSignal>
+    void Locked(CustomSignal&& signal)
+    {
+        std::lock_guard<std::mutex> lock(fMtx);
+        signal();
     }
 
     void Clear()
@@ -88,8 +120,29 @@ class StateQueue
     std::queue<fair::mq::State> fStates;
     std::mutex fMtx;
     std::condition_variable fCV;
+
+    // must be called under locked fMtx
+    fair::mq::State PopFrontUnsafe()
+    {
+        fair::mq::State state = fStates.front();
+        if (state == fair::mq::State::Error) {
+            throw DeviceErrorState("Controlled device transitioned to error state.");
+        }
+        fStates.pop();
+        return state;
+    }
+
+    // must be called under locked fMtx
+    std::pair<bool, fair::mq::State> ReturnPairUnsafe()
+    {
+        auto const pred = Predicate();
+        return {pred, pred ? PopFrontUnsafe() : fair::mq::State::Ok};
+    }
+
+    // must be called under locked fMtx
+    bool Predicate() { return !fStates.empty(); }
 };
 
-} // namespace fair::mq
+}   // namespace fair::mq
 
 #endif /* FAIRMQSTATEQUEUE_H_ */