[Server] Implement remove Characteristics/Descriptors. (#264)

This allows for adding and removing of characteristics and descriptors after initial setup of the server.
When used it will send a service changed notification to all clients.
The changes will not take effect until all clients have disconnected and advertising restarted.

Author: h2zero

src/NimBLECharacteristic.cpp

@@ -45,14 +45,15 @@ NimBLECharacteristic::NimBLECharacteristic(const char* uuid, uint16_t properties
  * @param [in] pService - pointer to the service instance this characteristic belongs to.
  */
 NimBLECharacteristic::NimBLECharacteristic(const NimBLEUUID &uuid, uint16_t properties, NimBLEService* pService) {
-    m_uuid       = uuid;
-    m_handle     = NULL_HANDLE;
-    m_properties = properties;
-    m_pCallbacks = &defaultCallback;
-    m_pService   = pService;
-    m_value      = "";
-    m_valMux     = portMUX_INITIALIZER_UNLOCKED;
-    m_timestamp  = 0;
+    m_uuid        = uuid;
+    m_handle      = NULL_HANDLE;
+    m_properties  = properties;
+    m_pCallbacks  = &defaultCallback;
+    m_pService    = pService;
+    m_value       = "";
+    m_valMux      = portMUX_INITIALIZER_UNLOCKED;
+    m_timestamp   = 0;
+    m_removed     = 0;
 } // NimBLECharacteristic
 
 /**
@@ -95,21 +96,63 @@ NimBLEDescriptor* NimBLECharacteristic::createDescriptor(const NimBLEUUID &uuid,
     }
 
     addDescriptor(pDescriptor);
-
     return pDescriptor;
 } // createDescriptor
 
 
 /**
  * @brief Add a descriptor to the characteristic.
- * @param [in] A pointer to the descriptor to add.
+ * @param [in] pDescriptor A pointer to the descriptor to add.
  */
 void NimBLECharacteristic::addDescriptor(NimBLEDescriptor *pDescriptor) {
+    bool foundRemoved = false;
+
+    if(pDescriptor->m_removed > 0) {
+        for(auto& it : m_dscVec) {
+            if(it == pDescriptor) {
+                foundRemoved = true;
+                pDescriptor->m_removed = 0;
+            }
+        }
+    }
+
+    if(!foundRemoved) {
+        m_dscVec.push_back(pDescriptor);
+    }
+
     pDescriptor->setCharacteristic(this);
-    m_dscVec.push_back(pDescriptor);
+    NimBLEDevice::getServer()->serviceChanged();
 }
 
 
+/**
+ * @brief Remove a descriptor from the characterisitc.
+ * @param[in] pDescriptor A pointer to the descriptor instance to remove from the characterisitc.
+ * @param[in] deleteDsc If true it will delete the descriptor instance and free it's resources.
+ */
+void NimBLECharacteristic::removeDescriptor(NimBLEDescriptor *pDescriptor, bool deleteDsc) {
+    // Check if the descriptor was already removed and if so, check if this
+    // is being called to delete the object and do so if requested.
+    // Otherwise, ignore the call and return.
+    if(pDescriptor->m_removed > 0) {
+        if(deleteDsc) {
+            for(auto it = m_dscVec.begin(); it != m_dscVec.end(); ++it) {
+                if ((*it) == pDescriptor) {
+                    delete *it;
+                    m_dscVec.erase(it);
+                    break;
+                }
+            }
+        }
+
+        return;
+    }
+
+    pDescriptor->m_removed = deleteDsc ? NIMBLE_ATT_REMOVE_DELETE : NIMBLE_ATT_REMOVE_HIDE;
+    NimBLEDevice::getServer()->serviceChanged();
+} // removeDescriptor
+
+
 /**
  * @brief Return the BLE Descriptor for the given UUID.
  * @param [in] uuid The UUID of the descriptor.

src/NimBLECharacteristic.h

@@ -99,6 +99,7 @@ class NimBLECharacteristic {
     NimBLEDescriptor* getDescriptorByUUID(const char* uuid);
     NimBLEDescriptor* getDescriptorByUUID(const NimBLEUUID &uuid);
     NimBLEDescriptor* getDescriptorByHandle(uint16_t handle);
+    void              removeDescriptor(NimBLEDescriptor *pDescriptor, bool deleteDsc = false);
 
     std::string       getValue(time_t *timestamp = nullptr);
     size_t            getDataLength();
@@ -152,6 +153,7 @@ class NimBLECharacteristic {
     std::vector<NimBLEDescriptor*> m_dscVec;
     portMUX_TYPE                   m_valMux;
     time_t                         m_timestamp;
+    uint8_t                        m_removed;
 
     std::vector<std::pair<uint16_t, uint16_t>>  m_subscribedVec;
 }; // NimBLECharacteristic

src/NimBLEDescriptor.cpp

@@ -53,6 +53,7 @@ NimBLEDescriptor::NimBLEDescriptor(NimBLEUUID uuid, uint16_t properties, uint16_
     m_value.attr_value   = (uint8_t*) calloc(max_len,1);  // Allocate storage for the value.
     m_valMux             = portMUX_INITIALIZER_UNLOCKED;
     m_properties         = 0;
+    m_removed            = 0;
 
     if (properties & BLE_GATT_CHR_F_READ) {             // convert uint16_t properties to uint8_t
         m_properties |= BLE_ATT_F_READ;

src/NimBLEDescriptor.h

@@ -93,6 +93,7 @@ class NimBLEDescriptor {
     uint8_t                    m_properties;
     attr_value_t               m_value;
     portMUX_TYPE               m_valMux;
+    uint8_t                    m_removed;
 }; // NimBLEDescriptor
 
 

src/NimBLEServer.cpp

@@ -91,12 +91,7 @@ NimBLEService* NimBLEServer::createService(const NimBLEUUID &uuid, uint32_t numH
 
     NimBLEService* pService = new NimBLEService(uuid, numHandles, this);
     m_svcVec.push_back(pService); // Save a reference to this service being on this server.
-
-    if(m_gattsStarted) {
-        ble_svc_gatt_changed(0x0001, 0xffff);
-        m_svcChanged = true;
-        resetGATT();
-    }
+    serviceChanged();
 
     NIMBLE_LOGD(LOG_TAG, "<< createService");
     return pService;
@@ -157,6 +152,18 @@ NimBLEAdvertising* NimBLEServer::getAdvertising() {
 } // getAdvertising
 
 
+/**
+ * @brief Sends a service changed notification and resets the GATT server.
+ */
+void NimBLEServer::serviceChanged() {
+    if(m_gattsStarted) {
+        m_svcChanged = true;
+        ble_svc_gatt_changed(0x0001, 0xffff);
+        resetGATT();
+    }
+}
+
+
 /**
  * @brief Start the GATT server. Required to be called after setup of all
  * services and characteristics / descriptors for the NimBLE host to register them.
@@ -630,7 +637,7 @@ void NimBLEServer::removeService(NimBLEService* service, bool deleteSvc) {
     if(service->m_removed > 0) {
         if(deleteSvc) {
             for(auto it = m_svcVec.begin(); it != m_svcVec.end(); ++it) {
-                if ((*it)->getUUID() == service->getUUID()) {
+                if ((*it) == service) {
                     delete *it;
                     m_svcVec.erase(it);
                     break;
@@ -646,11 +653,8 @@ void NimBLEServer::removeService(NimBLEService* service, bool deleteSvc) {
         return;
     }
 
-    service->m_removed = deleteSvc ? 2 : 1;
-    m_svcChanged = true;
-
-    ble_svc_gatt_changed(0x0001, 0xffff);
-    resetGATT();
+    service->m_removed = deleteSvc ? NIMBLE_ATT_REMOVE_DELETE : NIMBLE_ATT_REMOVE_HIDE;
+    serviceChanged();
     NimBLEDevice::getAdvertising()->removeServiceUUID(service->getUUID());
 }
 
@@ -677,10 +681,7 @@ void NimBLEServer::addService(NimBLEService* service) {
     }
 
     service->m_removed = 0;
-    m_svcChanged = true;
-
-    ble_svc_gatt_changed(0x0001, 0xffff);
-    resetGATT();
+    serviceChanged();
 }
 
 
@@ -699,7 +700,7 @@ void NimBLEServer::resetGATT() {
 
     for(auto it = m_svcVec.begin(); it != m_svcVec.end(); ) {
         if ((*it)->m_removed > 0) {
-            if ((*it)->m_removed == 2) {
+            if ((*it)->m_removed == NIMBLE_ATT_REMOVE_DELETE) {
                 delete *it;
                 it = m_svcVec.erase(it);
             } else {

src/NimBLEServer.h

@@ -20,6 +20,9 @@
 #include "nimconfig.h"
 #if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
 
+#define NIMBLE_ATT_REMOVE_HIDE 1
+#define NIMBLE_ATT_REMOVE_DELETE 2
+
 #include "NimBLEUtils.h"
 #include "NimBLEAddress.h"
 #include "NimBLEAdvertising.h"
@@ -69,6 +72,7 @@ class NimBLEServer {
     NimBLEServer();
     ~NimBLEServer();
     friend class           NimBLECharacteristic;
+    friend class           NimBLEService;
     friend class           NimBLEDevice;
     friend class           NimBLEAdvertising;
 
@@ -86,6 +90,7 @@ class NimBLEServer {
     std::vector<NimBLECharacteristic*> m_notifyChrVec;
 
     static int             handleGapEvent(struct ble_gap_event *event, void *arg);
+    void                   serviceChanged();
     void                   resetGATT();
     bool                   setIndicateWait(uint16_t conn_handle);
     void                   clearIndicateWait(uint16_t conn_handle);