Add a waitFinished method to thread pool

Author: Oscar Franco

cpp/ThreadPool.cpp

@@ -85,7 +85,13 @@ void ThreadPool::doWork()
       task = workQueue.front();
       workQueue.pop();
     }
-
+    ++busy;
     task();
+    --busy;
   }
 }
+
+void ThreadPool::waitFinished() {
+  std::unique_lock<std::mutex> g(workQueueMutex);
+  workQueueConditionVariable.wait(g, [&]{ return workQueue.empty() && (busy == 0); });
+}

cpp/ThreadPool.h

@@ -8,22 +8,23 @@
 #ifndef ThreadPool_hpp
 #define ThreadPool_hpp
 
-#include <stdio.h>
-#include <thread>
-#include <mutex>
 #include <condition_variable>
 #include <exception>
-#include <vector>
+#include <mutex>
 #include <queue>
+#include <stdio.h>
+#include <thread>
+#include <vector>
 
-class ThreadPool
-{
+class ThreadPool {
 public:
   ThreadPool();
   ~ThreadPool();
   void queueWork(std::function<void(void)> task);
-  
+  void waitFinished();
+
 private:
+  unsigned int busy;
   // This condition variable is used for the threads to wait until there is work
   // to do
   std::condition_variable_any workQueueConditionVariable;
@@ -40,7 +41,7 @@ class ThreadPool
   // This will be set to true when the thread pool is shutting down. This tells
   // the threads to stop looping and finish
   bool done;
-  
+
   // Function used by the threads to grab work from the queue
   void doWork();
 };