add ServiceDiscovery::isActive()

btle/btle_discovery.cpp

@@ -61,6 +61,12 @@ ServiceDiscovery::terminate(void)
     sdSingleton.terminateServiceDiscovery();
 }
 
+bool
+ServiceDiscovery::isActive(void)
+{
+    return sdSingleton.isActive();
+}
+
 ble_error_t
 NordicServiceDiscovery::launchCharacteristicDiscovery(Gap::Handle_t connectionHandle,
                                                       Gap::Handle_t startHandle,

btle/btle_discovery.h

@@ -49,6 +49,10 @@ public:
         serviceIndex++; /* Progress service index to keep discovery alive. */
     }
 
+    bool isActive(void) const {
+        return (sDiscoveryActive || cDiscoveryActive);
+    }
+
 private:
     void resetDiscoveredServices(void) {
         numServices  = 0;