ensure that no command gets lost

Author: mkalkbrenner

src/ZeDMDComm.cpp

@@ -132,7 +132,18 @@ void ZeDMDComm::QueueCommand(char command, uint8_t* data, int size)
     return;
   }
 
-  if (FillDelayed())
+  // It must be ensured that no command is lost.
+  // Losing frames is ok.
+  if (ZEDMD_COMM_COMMAND::ClearScreen != command)
+  {
+    uint8_t timeout = 0;
+    while (!IsQueueEmpty() && timeout < 10)
+    {
+      std::this_thread::sleep_for(std::chrono::milliseconds(200));
+      timeout++;
+    }
+  }
+  else if (FillDelayed())
   {
     ClearFrames();
   }
@@ -278,6 +289,14 @@ bool ZeDMDComm::FillDelayed()
   return delayed;
 }
 
+bool ZeDMDComm::IsQueueEmpty()
+{
+  m_frameQueueMutex.lock();
+  bool empty = m_frames.empty();
+  m_frameQueueMutex.unlock();
+  return empty;
+}
+
 void ZeDMDComm::IgnoreDevice(const char* ignore_device)
 {
   if (sizeof(ignore_device) < 32 && m_ignoredDevicesCounter < 10)

src/ZeDMDComm.h

@@ -237,6 +237,7 @@ class ZeDMDComm
   virtual void Reset();
   void Log(const char* format, ...);
   void ClearFrames();
+  bool IsQueueEmpty();
 
   char m_firmwareVersion[12] = "0.0.0";
   uint16_t m_width = 128;