DataFlash: StartUnstartedLogging replaces logging_started/start_logging

libraries/DataFlash/DataFlash.cpp

@@ -278,6 +278,17 @@ void DataFlash_Class::backend_starting_new_log(const DataFlash_Backend *backend)
     }
 }
 
+// start any backend which hasn't started; this is only called from
+// the vehicle code
+void DataFlash_Class::StartUnstartedLogging(void)
+{
+    for (uint8_t i=0; i<_next_backend; i++) {
+        if (!backends[i]->logging_started()) {
+            backends[i]->start_new_log();
+        }
+    }
+}
+
 #define FOR_EACH_BACKEND(methodcall)              \
     do {                                          \
         for (uint8_t i=0; i<_next_backend; i++) { \

libraries/DataFlash/DataFlash.h

@@ -105,7 +105,9 @@ public:
 
     void setVehicle_Startup_Log_Writer(vehicle_startup_message_Log_Writer writer);
 
-    void StartNewLog(void);
+    /* poke backends to start if they're not already started */
+    void StartUnstartedLogging(void);
+
     void EnableWrites(bool enable);
 
     void StopLogging();

libraries/DataFlash/LogFile.cpp

@@ -582,18 +582,6 @@ void DataFlash_Block::ListAvailableLogs(AP_HAL::BetterStream *port)
     port->printf("\n");
 }
 
-// This function starts a new log file in the DataFlash, and writes
-// the format of supported messages in the log
-// This function is ONLY called from the vehicle code.
-// DataFlash_MAVLink, for example, will NOT call this function if the
-// remote end disconnects and reconnects!
-void DataFlash_Class::StartNewLog(void)
-{
-    for (uint8_t i=0; i<_next_backend; i++) {
-        backends[i]->start_new_log();
-    }
-}
-
 /*
   write a structure format to the log - should be in frontend
  */