AP_ServoRelayEvents: add singleton

libraries/AP_ServoRelayEvents/AP_ServoRelayEvents.cpp

@@ -133,3 +133,15 @@ void AP_ServoRelayEvents::update_events(void)
         repeat ^= 1;
     }
 }
+
+// singleton instance
+AP_ServoRelayEvents *AP_ServoRelayEvents::_singleton;
+
+namespace AP {
+
+AP_ServoRelayEvents *servorelayevents()
+{
+    return AP_ServoRelayEvents::get_singleton();
+}
+
+}

libraries/AP_ServoRelayEvents/AP_ServoRelayEvents.h

@@ -13,20 +13,20 @@ class AP_ServoRelayEvents {
 public:
     AP_ServoRelayEvents(AP_Relay &_relay)
         : relay(_relay)
-        , mask(0)
         , type(EVENT_TYPE_RELAY)
-        , start_time_ms(0)
-        , delay_ms(0)
-        , repeat(0)
-        , channel(0)
-        , servo_value(0)
     {
+        _singleton = this;
     }
 
     /* Do not allow copies */
     AP_ServoRelayEvents(const AP_ServoRelayEvents &other) = delete;
     AP_ServoRelayEvents &operator=(const AP_ServoRelayEvents&) = delete;
 
+    // get singleton instance
+    static AP_ServoRelayEvents *get_singleton() {
+        return _singleton;
+    }
+
     // set allowed servo channel mask
     void set_channel_mask(uint16_t _mask) { mask = _mask; }
 
@@ -37,6 +37,9 @@ public:
     void update_events(void);
 
 private:
+
+    static AP_ServoRelayEvents *_singleton;
+
     AP_Relay &relay;
     uint16_t mask;
 
@@ -63,3 +66,7 @@ private:
 	// PWM for servos
 	uint16_t servo_value;
 };
+
+namespace AP {
+    AP_ServoRelayEvents *servorelayevents();
+};