AP_Baro: reduce header scope

We don't need to expose to other libraries how each backend is
implemented. AP_Baro.h is the main header, included by other libraries.

Instead of including each backend in the main header, move them to where
they are needed. Additionally standardize the order and how we include
the headers.

The advantages are:
	- Internals of each backend is not exposed outside of the
	  library
	- Faster incremental builds since we don't need to recompile
	  whoever includes AP_Baro.h because a backend changed

libraries/AP_Baro/AP_Baro.cpp

@@ -18,11 +18,16 @@
  *       APM_Baro.cpp - barometer driver
  *
  */
-
-#include <AP_Math/AP_Math.h>
-#include <AP_Common/AP_Common.h>
 #include "AP_Baro.h"
+
+#include <AP_Common/AP_Common.h>
 #include <AP_HAL/AP_HAL.h>
+#include <AP_Math/AP_Math.h>
+
+#include "AP_Baro_BMP085.h"
+#include "AP_Baro_HIL.h"
+#include "AP_Baro_MS5611.h"
+#include "AP_Baro_PX4.h"
 
 extern const AP_HAL::HAL& hal;
 

libraries/AP_Baro/AP_Baro.h

@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef __AP_BARO_H__
-#define __AP_BARO_H__
+#pragma once
 
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Param/AP_Param.h>
@@ -160,14 +158,6 @@ private:
 
     // when did we last notify the GCS of new pressure reference?
     uint32_t                            _last_notify_ms;
-    
+
     void SimpleAtmosphere(const float alt, float &sigma, float &delta, float &theta);
 };
-
-#include "AP_Baro_Backend.h"
-#include "AP_Baro_MS5611.h"
-#include "AP_Baro_BMP085.h"
-#include "AP_Baro_HIL.h"
-#include "AP_Baro_PX4.h"
-
-#endif // __AP_BARO_H__

libraries/AP_Baro/AP_Baro_BMP085.cpp

@@ -19,11 +19,10 @@
 
   Substantially modified by Andrew Tridgell
 */
+#include "AP_Baro_BMP085.h"
 
-#include <AP_HAL/AP_HAL.h>
 #include <AP_Common/AP_Common.h>
-
-#include "AP_Baro.h"
+#include <AP_HAL/AP_HAL.h>
 
 extern const AP_HAL::HAL& hal;
 

libraries/AP_Baro/AP_Baro_BMP085.h

@@ -1,8 +1,7 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-#ifndef __AP_BARO_BMP085_H__
-#define __AP_BARO_BMP085_H__
+#pragma once
 
-#include "AP_Baro.h"
+#include "AP_Baro_Backend.h"
 
 class AP_Baro_BMP085 : public AP_Baro_Backend
 {
@@ -23,7 +22,7 @@ private:
     // Flymaple has no EOC pin, so use times instead
     uint32_t        _last_press_read_command_time;
     uint32_t        _last_temp_read_command_time;
-    
+
     // State machine
     uint8_t                         BMP085_State;
 
@@ -41,5 +40,3 @@ private:
     void                            ReadTemp();
     void                            Calculate();
 };
-
-#endif // __AP_BARO_BMP085_H__

libraries/AP_Baro/AP_Baro_Backend.cpp

@@ -1,6 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#include "AP_Baro.h"
+#include "AP_Baro_Backend.h"
 
 extern const AP_HAL::HAL& hal;
 

libraries/AP_Baro/AP_Baro_Backend.h

@@ -1,7 +1,5 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#ifndef __AP_BARO_BACKEND_H__
-#define __AP_BARO_BACKEND_H__
+#pragma once
 
 #include "AP_Baro.h"
 
@@ -25,5 +23,3 @@ protected:
 
     void _copy_to_frontend(uint8_t instance, float pressure, float temperature);
 };
-
-#endif // __AP_BARO_BACKEND_H__

libraries/AP_Baro/AP_Baro_HIL.cpp

@@ -1,6 +1,6 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#include "AP_Baro_HIL.h"
 
-#include "AP_Baro.h"
 #include <AP_HAL/AP_HAL.h>
 
 extern const AP_HAL::HAL& hal;

libraries/AP_Baro/AP_Baro_HIL.h

@@ -3,11 +3,9 @@
   dummy backend for HIL (and SITL). This doesn't actually need to do
   any work, as setHIL() is in the frontend
  */
+#pragma once
 
-#ifndef __AP_BARO_HIL_H__
-#define __AP_BARO_HIL_H__
-
-#include "AP_Baro.h"
+#include "AP_Baro_Backend.h"
 
 class AP_Baro_HIL : public AP_Baro_Backend
 {
@@ -18,5 +16,3 @@ public:
 private:
     uint8_t _instance;
 };
-
-#endif //  __AP_BARO_HIL_H__

libraries/AP_Baro/AP_Baro_MS5611.cpp

@@ -19,9 +19,9 @@
 
   Heavily modified by Andrew Tridgell
 */
+#include "AP_Baro_MS5611.h"
 
 #include <AP_HAL/AP_HAL.h>
-#include "AP_Baro.h"
 
 extern const AP_HAL::HAL& hal;
 

libraries/AP_Baro/AP_Baro_MS5611.h

@@ -1,10 +1,9 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#pragma once
 
-#ifndef __AP_BARO_MS5611_H__
-#define __AP_BARO_MS5611_H__
+#include "AP_Baro_Backend.h"
 
 #include <AP_HAL/AP_HAL.h>
-#include "AP_Baro.h"
 
 /** Abstract serial bus device driver for I2C/SPI. */
 class AP_SerialBus
@@ -128,4 +127,3 @@ private:
     void _calculate();
     bool _read_prom(uint16_t prom[8]) override;
 };
-#endif //  __AP_BARO_MS5611_H__

libraries/AP_Baro/AP_Baro_PX4.cpp

@@ -1,11 +1,9 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#include "AP_Baro_PX4.h"
 
 #include <AP_HAL/AP_HAL.h>
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_PX4 || CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN
-#include "AP_Baro.h"
-#include "AP_Baro_PX4.h"
-
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>

libraries/AP_Baro/AP_Baro_PX4.h

@@ -1,9 +1,7 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#pragma once
 
-#ifndef __AP_BARO_PX4_H__
-#define __AP_BARO_PX4_H__
-
-#include "AP_Baro.h"
+#include "AP_Baro_Backend.h"
 
 class AP_Baro_PX4 : public AP_Baro_Backend
 {
@@ -23,5 +21,3 @@ private:
         uint64_t last_timestamp;
     } instances[BARO_MAX_INSTANCES];
 };
-
-#endif //  __AP_BARO_PX4_H__