MotionService : fix typo and characteristic array size + send notification only if the host subscribed to them.

Author: JF002

src/components/ble/HeartRateService.cpp

@@ -8,7 +8,7 @@ constexpr ble_uuid16_t HeartRateService::heartRateServiceUuid;
 constexpr ble_uuid16_t HeartRateService::heartRateMeasurementUuid;
 
 namespace {
-  int HeartRateServiceServiceCallback(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg) {
+  int HeartRateServiceCallback(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg) {
     auto* heartRateService = static_cast<HeartRateService*>(arg);
     return heartRateService->OnHeartRateRequested(conn_handle, attr_handle, ctxt);
   }
@@ -19,7 +19,7 @@ HeartRateService::HeartRateService(Pinetime::System::SystemTask& system, Control
   : system {system},
     heartRateController {heartRateController},
     characteristicDefinition {{.uuid = &heartRateMeasurementUuid.u,
-                               .access_cb = HeartRateServiceServiceCallback,
+                               .access_cb = HeartRateServiceCallback,
                                .arg = this,
                                .flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_NOTIFY,
                                .val_handle = &heartRateMeasurementHandle},
@@ -56,6 +56,8 @@ int HeartRateService::OnHeartRateRequested(uint16_t connectionHandle, uint16_t a
 }
 
 void HeartRateService::OnNewHeartRateValue(uint8_t heartRateValue) {
+  if(!heartRateMeasurementNotificationEnable) return;
+
   uint8_t buffer[2] = {0, heartRateController.HeartRate()}; // [0] = flags, [1] = hr value
   auto* om = ble_hs_mbuf_from_flat(buffer, 2);
 
@@ -67,3 +69,13 @@ void HeartRateService::OnNewHeartRateValue(uint8_t heartRateValue) {
 
   ble_gattc_notify_custom(connectionHandle, heartRateMeasurementHandle, om);
 }
+
+void HeartRateService::SubscribeNotification(uint16_t connectionHandle, uint16_t attributeHandle) {
+  if(attributeHandle == heartRateMeasurementHandle)
+    heartRateMeasurementNotificationEnable = true;
+}
+
+void HeartRateService::UnsubscribeNotification(uint16_t connectionHandle, uint16_t attributeHandle) {
+  if(attributeHandle == heartRateMeasurementHandle)
+    heartRateMeasurementNotificationEnable = false;
+}

src/components/ble/HeartRateService.h

@@ -2,6 +2,7 @@
 #define min // workaround: nimble's min/max macros conflict with libstdc++
 #define max
 #include <host/ble_gap.h>
+#include <atomic>
 #undef max
 #undef min
 
@@ -18,6 +19,9 @@ namespace Pinetime {
       int OnHeartRateRequested(uint16_t connectionHandle, uint16_t attributeHandle, ble_gatt_access_ctxt* context);
       void OnNewHeartRateValue(uint8_t hearRateValue);
 
+      void SubscribeNotification(uint16_t connectionHandle, uint16_t attributeHandle);
+      void UnsubscribeNotification(uint16_t connectionHandle, uint16_t attributeHandle);
+
     private:
       Pinetime::System::SystemTask& system;
       Controllers::HeartRateController& heartRateController;
@@ -28,10 +32,11 @@ namespace Pinetime {
 
       static constexpr ble_uuid16_t heartRateMeasurementUuid {.u {.type = BLE_UUID_TYPE_16}, .value = heartRateMeasurementId};
 
-      struct ble_gatt_chr_def characteristicDefinition[3];
+      struct ble_gatt_chr_def characteristicDefinition[2];
       struct ble_gatt_svc_def serviceDefinition[2];
 
       uint16_t heartRateMeasurementHandle;
+      std::atomic_bool heartRateMeasurementNotificationEnable {false};
     };
   }
 }

src/components/ble/NimbleController.cpp

@@ -215,6 +215,16 @@ int NimbleController::OnGAPEvent(ble_gap_event* event) {
                    event->subscribe.prev_notify,
                    event->subscribe.cur_notify,
                    event->subscribe.prev_indicate);
+
+      if(event->subscribe.reason == BLE_GAP_SUBSCRIBE_REASON_TERM) {
+        heartRateService.UnsubscribeNotification(event->subscribe.conn_handle, event->subscribe.attr_handle);
+      }
+      else if(event->subscribe.prev_notify == 0 && event->subscribe.cur_notify == 1) {
+        heartRateService.SubscribeNotification(event->subscribe.conn_handle, event->subscribe.attr_handle);
+      }
+      else if(event->subscribe.prev_notify == 1 && event->subscribe.cur_notify == 0) {
+        heartRateService.UnsubscribeNotification(event->subscribe.conn_handle, event->subscribe.attr_handle);
+      }
       break;
 
     case BLE_GAP_EVENT_MTU: