- thread pool can be paused now

src/engine/helper/HL_ThreadPool.h

@@ -11,13 +11,15 @@
 #include <functional>
 #include <stdexcept>
 
-class ThreadPool {
+class ThreadPool
+{
 public:
     ThreadPool(size_t);
     template<class F, class... Args>
     auto enqueue(F&& f, Args&&... args)
         -> std::future<typename std::result_of<F(Args...)>::type>;
     ~ThreadPool();
+    void setPause(bool v) { this->pause = v;}
 private:
     // need to keep track of threads so we can join them
     std::vector< std::thread > workers;
@@ -27,12 +29,12 @@ private:
     // synchronization
     std::mutex queue_mutex;
     std::condition_variable condition;
-    bool stop;
+    bool stop, pause;
 };
  
 // the constructor just launches some amount of workers
 inline ThreadPool::ThreadPool(size_t threads)
-    :   stop(false)
+    :   stop(false), pause(false)
 {
     for(size_t i = 0;i<threads;++i)
         workers.emplace_back(
@@ -45,9 +47,13 @@ inline ThreadPool::ThreadPool(size_t threads)
                     {
                         std::unique_lock<std::mutex> lock(this->queue_mutex);
                         this->condition.wait(lock,
-                            [this]{ return this->stop || !this->tasks.empty(); });
+                            [this]{ return this->stop || !this->pause || !this->tasks.empty(); });
+                        if (this->tasks.empty())
+                            std::this_thread::sleep_for(std::chrono::milliseconds(10));
                         if(this->stop && this->tasks.empty())
                             return;
+                        if(this->pause)
+                            continue;
                         task = std::move(this->tasks.front());
                         this->tasks.pop();
                     }