Update Thread.cpp

Fixed a bug that caused a race between ~Thread and Thread::Runner receiving a new job from the threadpool

src/Thread.cpp

@@ -5,13 +5,19 @@
 using namespace MultiThreading;
 
 Thread::~Thread() {
-    if (current_task)
-        current_task->WaitComplete();
-    stop = true;
+    std::shared_ptr<TaskBase> task;
 
+    {
+        std::lock_guard<std::mutex> lock(mtx);
+        task = current_task;
+    }
+
+    if (task)
+        task->WaitComplete();
+
+    stop = true;
     cv.notify_one();
     Join();
-    // Thread exits gracefully.
 }
 
 bool Thread::SetTask(std::shared_ptr<TaskBase> task) {
@@ -43,9 +49,10 @@ void Thread::Runner() {
         if (stop)
             break;
 
+        auto task = current_task;
         lock.unlock();
 
-        current_task->Run();
+        task->Run();
 
         lock.lock();