fix: allow StackSamplerLoopManager to be started after it is stopped

Author: korniltsev

profiler/src/ProfilerEngine/Datadog.Profiler.Native/CorProfilerCallback.cpp

@@ -2075,7 +2075,7 @@ void CorProfilerCallback::SetStackSamplerEnabled(bool enabled)
     }
     else
     {
-        _pStackSamplerLoopManager->Stop();
+        _pStackSamplerLoopManager->Stop2(ServiceBase::State::Init);
     }
 }
 

profiler/src/ProfilerEngine/Datadog.Profiler.Native/ServiceBase.cpp

@@ -44,6 +44,7 @@ bool ServiceBase::Start()
     if (result)
     {
         _currentState = State::Started;
+        Log::Debug("Service '", GetName(), "' started successfully.");
     }
     else
     {
@@ -56,6 +57,16 @@ bool ServiceBase::Start()
 
 bool ServiceBase::Stop()
 {
+    return Stop2(State::Stopped);
+}
+
+bool ServiceBase::Stop2(State stoppedState)
+{
+    if (stoppedState != State::Stopped && stoppedState != State::Init)
+    {
+        Log::Debug("Invalid final state to stop the service '", GetName(), "'. Expected State::Stopped or State::Init. Current state : ", to_string(_currentState.load()));
+        return false;
+    }
     auto expected = State::Started;
     auto exchange = _currentState.compare_exchange_strong(expected, State::Stopping);
 
@@ -68,7 +79,8 @@ bool ServiceBase::Stop()
     auto result = StopImpl();
     if (result)
     {
-        _currentState = State::Stopped;
+        _currentState = stoppedState;
+        Log::Debug("Service '", GetName(), "' stopped successfully. Current state : ", to_string(stoppedState));
     }
     else
     {
@@ -79,6 +91,7 @@ bool ServiceBase::Stop()
     return result;
 }
 
+
 ServiceBase::State ServiceBase::GetState() const
 {
     return _currentState;

profiler/src/ProfilerEngine/Datadog.Profiler.Native/ServiceBase.h

@@ -10,23 +10,27 @@
 class ServiceBase : public IService
 {
 public:
+    enum class State
+    {
+        Init,
+        Starting,
+        Started,
+        Stopping,
+        Stopped
+    };
     ServiceBase();
 
     bool Start() final override;
     bool Stop() final override;
 
+    // Like Stop, but allows to specify stopped state - either Stopped or Init. Init allows the service to be restarted.
+    bool Stop2(State stoppedState); // todo better name
+
 protected:
     virtual bool StartImpl() = 0;
     virtual bool StopImpl() = 0;
 
-    enum class State
-    {
-        Init,
-        Starting,
-        Started,
-        Stopping,
-        Stopped
-    };
+
 
     State GetState() const;