Add register for notify without callback

* Add subscribe() and unsubscribe() methods to replace registerForNotify() in NimBLERemoteCharacteristic.

* registerForNotify() remains as a (depreciated) method.

src/NimBLERemoteCharacteristic.cpp

@@ -494,7 +494,58 @@ int NimBLERemoteCharacteristic::onReadCB(uint16_t conn_handle,
 
 
 /**
- * @brief Register for notifications.
+ * @brief Subscribe or unsubscribe for notifications or indications.
+ * @param [in] uint16_t val 0x00 to unsubscribe, 0x01 for notifications, 0x02 for indications.
+ * @param [in] notifyCallback A callback to be invoked for a notification.  If NULL is provided then no callback
+ * is performed for notifications.
+ * @return true if successful.
+ */
+bool NimBLERemoteCharacteristic::setNotify(uint16_t val, bool response, notify_callback notifyCallback) {
+    NIMBLE_LOGD(LOG_TAG, ">> setNotify(): %s, %02x", toString().c_str(), val);
+
+    NimBLERemoteDescriptor* desc = getDescriptor(NimBLEUUID((uint16_t)0x2902));
+    if(desc == nullptr) {
+        NIMBLE_LOGE(LOG_TAG, "<< setNotify(): Could not get descriptor");
+        return false;
+    }
+
+    m_notifyCallback = notifyCallback;   // Save the notification callback.
+
+    NIMBLE_LOGD(LOG_TAG, "<< setNotify()");
+
+    return desc->writeValue((uint8_t *)&val, 2, response);
+} // setNotify
+
+
+/**
+ * @brief Subscribe for notifications or indications.
+ * @param [in] bool if true, subscribe for notifications, false subscribe for indications.
+ * @param [in] bool if true, require a write response from the descriptor write operation.
+ * @param [in] notifyCallback A callback to be invoked for a notification.  If NULL is provided then no callback
+ * is performed for notifications.
+ * @return true if successful.
+ */
+bool NimBLERemoteCharacteristic::subscribe(bool notifications, bool response, notify_callback notifyCallback) {
+    if(notifications) {
+        return setNotify(0x01, response, notifyCallback);
+    } else {
+        return setNotify(0x02, response, notifyCallback);
+    }
+} // subscribe
+
+
+/**
+ * @brief Unsubscribe for notifications or indications.
+ * @param [in] bool if true, require a write response from the descriptor write operation.
+ * @return true if successful.
+ */
+bool NimBLERemoteCharacteristic::unsubscribe(bool response) {
+    return setNotify(0x00, response);
+} // unsubscribe
+
+
+ /**
+ * @brief backward-compatibility method for subscribe/unsubscribe notifications/indications
  * @param [in] notifyCallback A callback to be invoked for a notification.  If NULL is provided then we are
  * unregistering for notifications.
  * @param [in] bool if true, register for notifications, false register for indications.
@@ -502,29 +553,13 @@ int NimBLERemoteCharacteristic::onReadCB(uint16_t conn_handle,
  * @return true if successful.
  */
 bool NimBLERemoteCharacteristic::registerForNotify(notify_callback notifyCallback, bool notifications, bool response) {
-    NIMBLE_LOGD(LOG_TAG, ">> registerForNotify(): %s", toString().c_str());
+    bool success;
-
-    m_notifyCallback = notifyCallback;   // Save the notification callback.
-
-    uint8_t val[] = {0x01, 0x00};
-
-    NimBLERemoteDescriptor* desc = getDescriptor(NimBLEUUID((uint16_t)0x2902));
-    if(desc == nullptr)
-        return false;
-
     if(notifyCallback != nullptr) {
-        if(!notifications){
+        success = subscribe(notifications, response, notifyCallback);
-            val[0] = 0x02;
+    } else {
+        success = unsubscribe(response);
     }
-    }
+    return success;
-
-    else if (notifyCallback == nullptr){
-        val[0] = 0x00;
-    }
-
-    NIMBLE_LOGD(LOG_TAG, "<< registerForNotify()");
-
-    return desc->writeValue(val, 2, response);
 } // registerForNotify
 
 

src/NimBLERemoteCharacteristic.h

@@ -78,9 +78,13 @@ public:
         return *((T *)pData);
     }
 
-    bool                                           registerForNotify(notify_callback _callback,
+    bool                                           subscribe(bool notifications = true,
+                                                             bool response = true,
+                                                             notify_callback notifyCallback = nullptr);
+    bool                                           unsubscribe(bool response = true);
+    bool                                           registerForNotify(notify_callback notifyCallback,
                                                                      bool notifications = true,
-                                                                     bool response = true);
+                                                                     bool response = true) __attribute__ ((deprecated));
     bool                                           writeValue(const uint8_t* data,
                                                               size_t length,
                                                               bool response = false);
@@ -100,6 +104,7 @@ private:
     friend class      NimBLERemoteDescriptor;
 
     // Private member functions
+    bool              setNotify(uint16_t val, bool response = true, notify_callback notifyCallback = nullptr);
     bool              retrieveDescriptors(const NimBLEUUID *uuid_filter = nullptr);
     static int        onReadCB(uint16_t conn_handle, const struct ble_gatt_error *error,
                                struct ble_gatt_attr *attr, void *arg);