SML power meter: improve message output

* when printing a message, tell the name of the derived class.
* print total power only when state SML_FINAL reached.
* tell if a checksum verification error occurred.

include/PowerMeterHttpSml.h

@@ -14,7 +14,8 @@
 class PowerMeterHttpSml : public PowerMeterSml {
 public:
     explicit PowerMeterHttpSml(PowerMeterHttpSmlConfig const& cfg)
-        : _cfg(cfg) { }
+        : PowerMeterSml("PowerMeterHttpSml")
+        , _cfg(cfg) { }
 
     ~PowerMeterHttpSml();
 

include/PowerMeterSerialSml.h

@@ -6,6 +6,9 @@
 
 class PowerMeterSerialSml : public PowerMeterSml {
 public:
+    PowerMeterSerialSml()
+        : PowerMeterSml("PowerMeterSerialSml") { }
+
     ~PowerMeterSerialSml();
 
     bool init() final;

include/PowerMeterSml.h

@@ -16,9 +16,13 @@ public:
     void doMqttPublish() const final;
 
 protected:
+    explicit PowerMeterSml(char const* user)
+        : _user(user) { }
+
     void processSmlByte(uint8_t byte);
 
 private:
+    std::string _user;
     mutable std::mutex _mutex;
 
     float _activePowerTotal = 0.0;

src/PowerMeterSerialSml.cpp

@@ -39,5 +39,4 @@ void PowerMeterSerialSml::loop()
         processSmlByte(_upSmlSerial->read());
     }
 
-    MessageOutput.printf("[PowerMeterSerialSml]: TotalPower: %5.2f\r\n", getPowerTotal());
 }

src/PowerMeterSml.cpp

@@ -37,11 +37,19 @@ void PowerMeterSml::processSmlByte(uint8_t byte)
                 handler.decoder(*handler.target);
 
                 if (_verboseLogging) {
-                    MessageOutput.printf("[PowerMeterSml] decoded %s to %.2f\r\n",
-                            handler.name, *handler.target);
+                    MessageOutput.printf("[%s] decoded %s to %.2f\r\n",
+                            _user.c_str(), handler.name, *handler.target);
                 }
             }
             break;
+        case SML_FINAL:
+            MessageOutput.printf("[%s] TotalPower: %5.2f\r\n",
+                    _user.c_str(), getPowerTotal());
+            break;
+        case SML_CHECKSUM_ERROR:
+            MessageOutput.printf("[%s] checksum verification failed\r\n",
+                    _user.c_str());
+            break;
         default:
             break;
     }