NTS pause capability

src/utils/nts.cpp

@@ -10,6 +10,7 @@
 #include "common.hpp"
 
 #define WAIT_TIME_IF_NO_TIMER 500
+#define PAUSE_POLLING_PERIOD 150
 
 static NtsMessage *TimerExpiredMessage(TimerInfo *timerInfo)
 {
@@ -204,7 +205,17 @@ void NtsTask::start()
             {
                 if (this->isQuiting)
                     break;
-                this->onLoop();
+
+                if (pauseReqCount > 0)
+                {
+                    utils::Sleep(PAUSE_POLLING_PERIOD);
+                    pauseConfirmed = true;
+                }
+                else
+                {
+                    pauseConfirmed = false;
+                    this->onLoop();
+                }
             }
         }};
     }
@@ -233,3 +244,20 @@ void NtsTask::quit()
 
     onQuit();
 }
+
+void NtsTask::requestPause()
+{
+    if (++pauseReqCount < 0)
+        throw std::runtime_error("NTS pause overflow");
+}
+
+void NtsTask::requestUnpause()
+{
+    if (--pauseReqCount < 0)
+        throw std::runtime_error("NTS un-pause underflow");
+}
+
+bool NtsTask::isPauseConfirmed()
+{
+    return pauseConfirmed;
+}

src/utils/nts.hpp

@@ -112,7 +112,9 @@ class NtsTask
     TimerBase timerBase{};
     std::mutex mutex{};
     std::condition_variable cv{};
-    std::atomic<bool> isQuiting{};
+    std::atomic_bool isQuiting{};
+    std::atomic_int pauseReqCount{};
+    std::atomic_bool pauseConfirmed{};
     std::thread thread;
 
   public:
@@ -163,4 +165,16 @@ class NtsTask
     // - Always call this function before destroying the task.
     // - Calling quit() before calling start() is undefined behaviour.
     void quit();
+
+    // - NTS task begin to be paused. The pause request is confirmed after the next loop() call.
+    // - If the task quits immediately and loop() never called again, this pause request will never be confirmed.
+    // - This should not be used if the task is quiting or quited.
+    void requestPause();
+
+    // - NTS task begin to be un-paused. The un-pause request is confirmed after the next loop() call.
+    // - This should not be used if the task is quiting or quited.
+    void requestUnpause();
+
+    // - Returns true iff pause was requested and now is confirmed.
+    bool isPauseConfirmed();
 };
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