Specialize scheduler pointer to allow devirtualization of method calls (#9225)

arangod/Scheduler/SchedulerFeature.cpp

@@ -65,7 +65,7 @@ size_t defaultNumberOfThreads() {
 
 namespace arangodb {
 
-Scheduler* SchedulerFeature::SCHEDULER = nullptr;
+SupervisedScheduler* SchedulerFeature::SCHEDULER = nullptr;
 
 SchedulerFeature::SchedulerFeature(application_features::ApplicationServer& server)
     : ApplicationFeature(server, "Scheduler"), 
@@ -162,19 +162,21 @@ void SchedulerFeature::validateOptions(std::shared_ptr<options::ProgramOptions>)
 void SchedulerFeature::prepare() {
   TRI_ASSERT(2 <= _nrMinimalThreads);
   TRI_ASSERT(_nrMinimalThreads <= _nrMaximalThreads);
-
-//wait for windows fix or implement operator new
+// wait for windows fix or implement operator new
 #if (_MSC_VER >= 1)
 #pragma warning(push)
 #pragma warning(disable : 4316)  // Object allocated on the heap may not be aligned for this type
 #endif
-  _scheduler =
+  auto sched =
       std::make_unique<SupervisedScheduler>(_nrMinimalThreads, _nrMaximalThreads,
                                             _queueSize, _fifo1Size, _fifo2Size);
 #if (_MSC_VER >= 1)
 #pragma warning(pop)
 #endif
-  SCHEDULER = _scheduler.get();
+
+  SCHEDULER = sched.get();
+
+  _scheduler = std::move(sched);
 }
 
 void SchedulerFeature::start() {

arangod/Scheduler/SchedulerFeature.h

@@ -27,12 +27,13 @@
 #include "ApplicationFeatures/ApplicationFeature.h"
 #include "GeneralServer/Socket.h"  // This is required for asio_ns::signal_set
 #include "Scheduler/Scheduler.h"
+#include "Scheduler/SupervisedScheduler.h"
 
 namespace arangodb {
 
 class SchedulerFeature final : public application_features::ApplicationFeature {
  public:
-  static Scheduler* SCHEDULER;
+  static SupervisedScheduler* SCHEDULER;
 
   explicit SchedulerFeature(application_features::ApplicationServer& server);
   ~SchedulerFeature();

tests/Cluster/ClusterCommTest.cpp

@@ -78,7 +78,7 @@ class ClusterCommTester : public ClusterComm {
     somethingReceived.broadcast();
   }  // signalResponse
 
-  Scheduler* _oldSched;
+  decltype(SchedulerFeature::SCHEDULER) _oldSched;
   SupervisedScheduler _testerSched;
 
 };  // class ClusterCommTester