Scope the Func object and check for empty funcs_ queue (#112)

Author: jgilje

trantor/net/EventLoop.cc

@@ -285,10 +285,15 @@ void EventLoop::doRunInLoopFuncs()
 {
     callingFuncs_ = true;
     {
-        Func func;
-        while (funcs_.dequeue(func))
+        // the destructor for the Func may itself insert a new entry into the
+        // queue
+        while (!funcs_.empty())
         {
-            func();
+            Func func;
+            while (funcs_.dequeue(func))
+            {
+                func();
+            }
         }
     }
     callingFuncs_ = false;

trantor/utils/LockFreeQueue.h

@@ -86,6 +86,13 @@ class MpscQueue : public NonCopyable
         return true;
     }
 
+    bool empty()
+    {
+        BufferNode *tail = tail_.load(std::memory_order_relaxed);
+        BufferNode *next = tail->next_.load(std::memory_order_acquire);
+        return next == nullptr;
+    }
+
   private:
     struct BufferNode
     {