Fix for issue 3974 m_connectedCount incorrectly decremented when no connection exists

There is no need to decrement if nothing was removed from removePeerDevice

Reference issue:
#3974

libraries/BLE/src/BLEServer.cpp

@@ -202,13 +202,19 @@ void BLEServer::handleGATTServerEvent(esp_gatts_cb_event_t event, esp_gatt_if_t
 		// If we receive a disconnect event then invoke the callback for disconnects (if one is present).
 		// we also want to start advertising again.
 		case ESP_GATTS_DISCONNECT_EVT: {
-			m_connectedCount--;                          // Decrement the number of connected devices count.
 			if (m_pServerCallbacks != nullptr) {         // If we have callbacks, call now.
 				m_pServerCallbacks->onDisconnect(this);
 			}
-			startAdvertising(); //- do this with some delay from the loop()
-			removePeerDevice(param->disconnect.conn_id, false);
-			break;
+            if(m_connId == ESP_GATT_IF_NONE) {
+                return;
+            }
+
+            // only decrement if connection is found in map and removed
+            // sometimes this event triggers w/o a valid connection
+			if(removePeerDevice(param->disconnect.conn_id, false)) {
+                m_connectedCount--;                          // Decrement the number of connected devices count.
+            }
+            break;
 		} // ESP_GATTS_DISCONNECT_EVT
 
 
@@ -395,8 +401,8 @@ void BLEServer::addPeerDevice(void* peer, bool _client, uint16_t conn_id) {
 	m_connectedServersMap.insert(std::pair<uint16_t, conn_status_t>(conn_id, status));	
 }
 
-void BLEServer::removePeerDevice(uint16_t conn_id, bool _client) {
-	m_connectedServersMap.erase(conn_id);
+bool BLEServer::removePeerDevice(uint16_t conn_id, bool _client) {
+	return m_connectedServersMap.erase(conn_id) > 0;
 }
 /* multi connect support */
 

libraries/BLE/src/BLEServer.h

@@ -79,7 +79,7 @@ public:
 	/* multi connection support */
 	std::map<uint16_t, conn_status_t> getPeerDevices(bool client);
 	void addPeerDevice(void* peer, bool is_client, uint16_t conn_id);
-	void removePeerDevice(uint16_t conn_id, bool client);
+	bool removePeerDevice(uint16_t conn_id, bool client);
 	BLEServer* getServerByConnId(uint16_t conn_id);
 	void updatePeerMTU(uint16_t connId, uint16_t mtu);
 	uint16_t getPeerMTU(uint16_t conn_id);