AP_AIS: add dummy methods

libraries/AP_AIS/AP_AIS.cpp

@@ -21,6 +21,12 @@
 
 #if AP_AIS_ENABLED
 
+#include <AP_Vehicle/AP_Vehicle_Type.h>
+
+#define AP_AIS_DUMMY_METHODS_ENABLED ((AP_AIS_ENABLED == 2) && !APM_BUILD_TYPE(APM_BUILD_Rover))
+
+#if !AP_AIS_DUMMY_METHODS_ENABLED
+
 #include <AP_Logger/AP_Logger.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
 #include <GCS_MAVLink/GCS.h>
@@ -71,6 +77,12 @@ AP_AIS::AP_AIS()
     AP_Param::setup_object_defaults(this, var_info);
 }
 
+// return true if AIS is enabled
+bool AP_AIS::enabled() const
+{ 
+    return AISType(_type.get()) != AISType::NONE;
+}
+
 // Initialize the AIS object and prepare it for use
 void AP_AIS::init()
 {
@@ -809,6 +821,30 @@ bool AP_AIS::decode_latest_term()
     return false;
 }
 
+// get singleton instance
+AP_AIS *AP_AIS::get_singleton() {
+    return _singleton;
+}
+
+#else
+// Dummy methods are required to allow functionality to be enabled for Rover.
+// It is not posible to compile in or out the full code based on vehicle type due to limitations
+// of the handling of `APM_BUILD_TYPE` define.
+// These dummy methods minimise flash cost in that case.
+
+const AP_Param::GroupInfo AP_AIS::var_info[] = { AP_GROUPEND };
+AP_AIS::AP_AIS() {};
+
+bool AP_AIS::enabled() const { return false; }
+
+void AP_AIS::init() {};
+void AP_AIS::update() {};
+void AP_AIS::send(mavlink_channel_t chan) {};
+
+AP_AIS *AP_AIS::get_singleton() { return nullptr; }
+
+#endif // AP_AIS_DUMMY_METHODS_ENABLED
+
 AP_AIS *AP_AIS::_singleton;
 
 #endif  // AP_AIS_ENABLED

libraries/AP_AIS/AP_AIS.h

@@ -17,10 +17,17 @@
 #include <AP_HAL/AP_HAL_Boards.h>
 
 #ifndef AP_AIS_ENABLED
-#define AP_AIS_ENABLED !HAL_MINIMIZE_FEATURES
+#if BOARD_FLASH_SIZE <= 1024
+    #define AP_AIS_ENABLED 0
+#else
+    #define AP_AIS_ENABLED 2
+#endif
 #endif
 
 #if AP_AIS_ENABLED
+// 0 fully disabled and compiled out
+// 1 compiled in and enabled
+// 2 compiled in with dummy methods, none functional, except rover which never uses dummy methods functionality
 
 #include <AP_Param/AP_Param.h>
 #include <AP_SerialManager/AP_SerialManager.h>
@@ -34,17 +41,13 @@ class AP_AIS
 public:
     AP_AIS();
 
-    /* Do not allow copies */
-    AP_AIS(const AP_AIS &other) = delete;
-    AP_AIS &operator=(const AP_AIS&) = delete;
+    CLASS_NO_COPY(AP_AIS);
 
     // get singleton instance
-    static AP_AIS *get_singleton() {
-        return _singleton;
-    }
+    static AP_AIS *get_singleton();
 
     // return true if AIS is enabled
-    bool enabled() const { return AISType(_type.get()) != AISType::NONE; }
+    bool enabled() const;
 
     // Initialize the AIS object and prepare it for use
     void init();