messages that expect a reply may optionally block to wait for it.

protocol/enttec/dmx-usb-pro/widget.cpp

@@ -23,6 +23,8 @@
 */
 #include "widget.h"
 
+#include <chrono>
+
 namespace ENTTEC {
 
 Widget::Widget()
@@ -386,24 +388,55 @@ void Widget::rebootBootloader()
 
 /**
  * @brief Widget::getSerialNumber
- * @param timeout block for up to 'timeout' milliseconds waiting for a reply
+ * @param timeout Milliseconds to block while waiting for the device to reply.
+ * @return True if the serial number has been updated.
  */
-void Widget::getSerialNumber()
+bool Widget::getSerialNumber(int timeout)
 {
+  {
+    std::scoped_lock lock(mtx_metadata_);
+    reply_serialNumber_ = std::promise<bool>();     // expect a reply to this message
+  }
+  auto ftr = reply_serialNumber_.get_future();      // will be "true" when reply received
   auto msg = std::make_shared<Pro::MsgGetWidgetSerialRequest>();
   sendMessage(msg);
+  auto status = ftr.wait_for(std::chrono::milliseconds(timeout)); // wait for the reply
+  switch (status) {
+  case std::future_status::ready:
+    return true;
+  case std::future_status::timeout:
+    return false;
+  default:
+    return false;
+  }
 }
 
 
 /**
  * @brief Widget::getParameters
  * @param user_length
+ * @param timeout Milliseconds to block while waiting for the device to reply.
+ * @return True if the parameters has been updated.
  */
-void Widget::getParameters(size_t user_length)
+bool Widget::getParameters(size_t user_length, int timeout)
 {
+  {
+    std::scoped_lock lock(mtx_metadata_);
+    reply_parameters_ = std::promise<bool>();       // expect a reply to this message
+  }
+  auto ftr = reply_parameters_.get_future();        // will be "true" when reply received
   auto msg = std::make_shared<Pro::MsgGetWidgetParametersRequest>();
   msg->size = std::min(user_length, Pro::USER_CONFIGURATION_MAX);
   sendMessage(msg);
+  auto status = ftr.wait_for(std::chrono::milliseconds(timeout)); // wait for the reply
+  switch (status) {
+  case std::future_status::ready:
+    return true;
+  case std::future_status::timeout:
+    return false;
+  default:
+    return false;
+  }
 }
 
 

protocol/enttec/dmx-usb-pro/widget.h

@@ -26,6 +26,7 @@
 #include "pro.h"
 
 #include <cstring>
+#include <future>
 #include <mutex>
 #include <universe.h>
 #include <vector>
@@ -78,9 +79,9 @@ protected:
   // USB Host operations
   virtual void sendMessage(std::shared_ptr<Pro::MessageData>) const;
   void rebootBootloader();
-  void getParameters(size_t user_length = 0);
+  bool getParameters(size_t user_length = 0, int timeout = 0);
   void setParameters() const;
-  void getSerialNumber();
+  bool getSerialNumber(int timeout = 0);
   void sendDmx(bool trimmed = true) const;
 
   /**
@@ -123,6 +124,8 @@ private:
 
   mutable std::mutex mtx_metadata_;
   std::shared_ptr<void> token_data_changed_;
+  std::promise<bool> reply_parameters_;
+  std::promise<bool> reply_serialNumber_;
 };
 
 } // namespace ENTTEC