AP_Logger: rearrange PrepForArming stuff

libraries/AP_Logger/AP_Logger_Backend.cpp

@@ -459,25 +459,16 @@ bool AP_Logger_Backend::ShouldLog(bool is_critical)
     return true;
 }
 
-// check if we should rotate when arming
-void AP_Logger_Backend::arming_rotate_check(void)
+void AP_Logger_Backend::PrepForArming()
 {
     if (_rotate_pending) {
         _rotate_pending = false;
         stop_logging();
     }
-}
-
-/*
-  setup for armed state, starting logging
-  This function is replaced in the File backend
- */
-void AP_Logger_Backend::PrepForArming()
-{
-    arming_rotate_check();
-    if (!logging_started()) {
-        start_new_log();
+    if (logging_started()) {
+        return;
     }
+    PrepForArming_start_logging();
 }
 
 bool AP_Logger_Backend::Write_MessageF(const char *fmt, ...)

libraries/AP_Logger/AP_Logger_Backend.h

@@ -144,8 +144,10 @@ protected:
     virtual bool WritesOK() const = 0;
     virtual bool StartNewLogOK() const;
 
-    // check if we should rotate when arming
-    void arming_rotate_check(void);
+    // called by PrepForArming to actually start logging
+    virtual void PrepForArming_start_logging(void) {
+        start_new_log();
+    }
 
     /*
       read a block

libraries/AP_Logger/AP_Logger_File.cpp

@@ -710,17 +710,14 @@ void AP_Logger_File::stop_logging(void)
 }
 
 /*
-  wrapper for PrepForArming to move start_new_log to the logger thread
+  does start_new_log in the logger thread
  */
-void AP_Logger_File::PrepForArming()
+void AP_Logger_File::PrepForArming_start_logging()
 {
-#if APM_BUILD_TYPE(APM_BUILD_Replay)
-    AP_Logger_Backend::PrepForArming();
-#else
-    arming_rotate_check();
     if (logging_started()) {
         return;
     }
+
     uint32_t start_ms = AP_HAL::millis();
     const uint32_t open_limit_ms = 250;
 
@@ -736,7 +733,6 @@ void AP_Logger_File::PrepForArming()
         }
         hal.scheduler->delay(1);
     }
-#endif
 }
 
 /*

libraries/AP_Logger/AP_Logger_File.h

@@ -61,7 +61,7 @@ protected:
 
     bool WritesOK() const override;
     bool StartNewLogOK() const override;
-    void PrepForArming() override;
+    void PrepForArming_start_logging() override;
 
 private:
     int _write_fd = -1;