Both the MQTT client (MqttClient) and the BearSSL client (BearSSLClient) are allocated on the stack instead of the heap.

This means that the memory consumption of those two rather large classes are directly visibale in the compilation output since ArduinoIoTCloud is instantiated as a global variable. The heap allocation is not directly visible to the user of the library and so gives the wrong impression that there is a lot of free space left.

Author: aentinger

src/ArduinoIoTCloudTCP.cpp

@@ -64,11 +64,13 @@ ArduinoIoTCloudTCP::ArduinoIoTCloudTCP()
 , _mqtt_data_buf{0}
 , _mqtt_data_len{0}
 , _mqtt_data_request_retransmit{false}
-, _sslClient(NULL)
+#ifdef BOARD_HAS_ECCX08
+, _sslClient(nullptr, ArduinoIoTCloudTrustAnchor, ArduinoIoTCloudTrustAnchor_NUM)
+#endif
   #ifdef BOARD_ESP
 , _password("")
   #endif
-, _mqttClient(NULL)
+, _mqttClient{nullptr}
 , _syncStatus{ArduinoIoTSynchronizationStatus::SYNC_STATUS_SYNCHRONIZED}
 , _stdinTopic("")
 , _stdoutTopic("")
@@ -85,12 +87,6 @@ ArduinoIoTCloudTCP::ArduinoIoTCloudTCP()
 
 }
 
-ArduinoIoTCloudTCP::~ArduinoIoTCloudTCP()
-{
-  delete _mqttClient; _mqttClient = NULL;
-  delete _sslClient;  _sslClient = NULL;
-}
-
 /******************************************************************************
  * PUBLIC MEMBER FUNCTIONS
  ******************************************************************************/
@@ -115,21 +111,20 @@ int ArduinoIoTCloudTCP::begin(String brokerAddress, uint16_t brokerPort)
   if (!CryptoUtil::readDeviceId(ECCX08, getDeviceId(), ECCX08Slot::DeviceId))                                                                                                  { Debug.print(DBG_ERROR, "Cryptography processor read failure."); return 0; }
   if (!CryptoUtil::reconstructCertificate(_eccx08_cert, getDeviceId(), ECCX08Slot::Key, ECCX08Slot::CompressedCertificate, ECCX08Slot::SerialNumberAndAuthorityKeyIdentifier)) { Debug.print(DBG_ERROR, "Cryptography certificate reconstruction failure."); return 0; }
   ArduinoBearSSL.onGetTime(getTime);
-  _sslClient = new BearSSLClient(_connection->getClient(), ArduinoIoTCloudTrustAnchor, ArduinoIoTCloudTrustAnchor_NUM);
-  _sslClient->setEccSlot(static_cast<int>(ECCX08Slot::Key), _eccx08_cert.bytes(), _eccx08_cert.length());
+  _sslClient.setClient(_connection->getClient());
+  _sslClient.setEccSlot(static_cast<int>(ECCX08Slot::Key), _eccx08_cert.bytes(), _eccx08_cert.length());
   #elif defined(BOARD_ESP)
-  _sslClient = new WiFiClientSecure();
-  _sslClient->setInsecure();
+  _sslClient.setInsecure();
   #endif
 
-  _mqttClient = new MqttClient(*_sslClient);
+  _mqttClient.setClient(_sslClient);
   #ifdef BOARD_ESP
-  _mqttClient->setUsernamePassword(getDeviceId(), _password);
+  _mqttClient.setUsernamePassword(getDeviceId(), _password);
   #endif
-  _mqttClient->onMessage(ArduinoIoTCloudTCP::onMessage);
-  _mqttClient->setKeepAliveInterval(30 * 1000);
-  _mqttClient->setConnectionTimeout(1500);
-  _mqttClient->setId(getDeviceId().c_str());
+  _mqttClient.onMessage(ArduinoIoTCloudTCP::onMessage);
+  _mqttClient.setKeepAliveInterval(30 * 1000);
+  _mqttClient.setConnectionTimeout(1500);
+  _mqttClient.setId(getDeviceId().c_str());
 
   _stdinTopic     = getTopic_stdin();
   _stdoutTopic    = getTopic_stdout();
@@ -170,7 +165,7 @@ void ArduinoIoTCloudTCP::update()
   }
 
   // MTTQClient connected!, poll() used to retrieve data from MQTT broker
-  _mqttClient->poll();
+  _mqttClient.poll();
 
   switch (_syncStatus)
   {
@@ -197,7 +192,7 @@ void ArduinoIoTCloudTCP::update()
 
 int ArduinoIoTCloudTCP::connected()
 {
-  return _mqttClient->connected();
+  return _mqttClient.connected();
 }
 
 void ArduinoIoTCloudTCP::printDebugInfo()
@@ -220,8 +215,8 @@ void ArduinoIoTCloudTCP::setOTAStorage(OTAStorage & ota_storage)
 
 int ArduinoIoTCloudTCP::reconnect()
 {
-  if (_mqttClient->connected()) {
-    _mqttClient->stop();
+  if (_mqttClient.connected()) {
+    _mqttClient.stop();
   }
   return connect();
 }
@@ -232,14 +227,14 @@ int ArduinoIoTCloudTCP::reconnect()
 
 int ArduinoIoTCloudTCP::connect()
 {
-  if (!_mqttClient->connect(_brokerAddress.c_str(), _brokerPort)) return CONNECT_FAILURE;
-  if (_mqttClient->subscribe(_stdinTopic) == 0)                   return CONNECT_FAILURE_SUBSCRIBE;
-  if (_mqttClient->subscribe(_dataTopicIn) == 0)                  return CONNECT_FAILURE_SUBSCRIBE;
-  if (_mqttClient->subscribe(_ota_topic_in) == 0)                 return CONNECT_FAILURE_SUBSCRIBE;
+  if (!_mqttClient.connect(_brokerAddress.c_str(), _brokerPort)) return CONNECT_FAILURE;
+  if (_mqttClient.subscribe(_stdinTopic) == 0)                   return CONNECT_FAILURE_SUBSCRIBE;
+  if (_mqttClient.subscribe(_dataTopicIn) == 0)                  return CONNECT_FAILURE_SUBSCRIBE;
+  if (_mqttClient.subscribe(_ota_topic_in) == 0)                 return CONNECT_FAILURE_SUBSCRIBE;
 
   if (_shadowTopicIn != "")
   {
-    if (_mqttClient->subscribe(_shadowTopicIn) == 0)              return CONNECT_FAILURE_SUBSCRIBE;
+    if (_mqttClient.subscribe(_shadowTopicIn) == 0)              return CONNECT_FAILURE_SUBSCRIBE;
     _syncStatus = ArduinoIoTSynchronizationStatus::SYNC_STATUS_WAIT_FOR_CLOUD_VALUES;
     _lastSyncRequestTickTime = 0;
   }
@@ -249,7 +244,7 @@ int ArduinoIoTCloudTCP::connect()
 
 void ArduinoIoTCloudTCP::disconnect()
 {
-  _mqttClient->stop();
+  _mqttClient.stop();
 }
 
 /******************************************************************************
@@ -263,12 +258,12 @@ void ArduinoIoTCloudTCP::onMessage(int length)
 
 void ArduinoIoTCloudTCP::handleMessage(int length)
 {
-  String topic = _mqttClient->messageTopic();
+  String topic = _mqttClient.messageTopic();
 
   byte bytes[length];
 
   for (int i = 0; i < length; i++) {
-    bytes[i] = _mqttClient->read();
+    bytes[i] = _mqttClient.read();
   }
 
   if (_stdinTopic == topic) {
@@ -354,7 +349,7 @@ ArduinoIoTConnectionStatus ArduinoIoTCloudTCP::checkCloudConnection()
 
     case ArduinoIoTConnectionStatus::CONNECTED:
     {
-      if (!_mqttClient->connected())
+      if (!_mqttClient.connected())
       {
         next_iot_status = ArduinoIoTConnectionStatus::DISCONNECTED;
         _mqtt_data_request_retransmit = true;
@@ -376,9 +371,9 @@ ArduinoIoTConnectionStatus ArduinoIoTCloudTCP::checkCloudConnection()
 
 int ArduinoIoTCloudTCP::write(String const topic, byte const data[], int const length)
 {
-  if (_mqttClient->beginMessage(topic, length, false, 0)) {
-    if (_mqttClient->write(data, length)) {
-      if (_mqttClient->endMessage()) {
+  if (_mqttClient.beginMessage(topic, length, false, 0)) {
+    if (_mqttClient.write(data, length)) {
+      if (_mqttClient.endMessage()) {
         return 1;
       }
     }

src/ArduinoIoTCloudTCP.h

@@ -58,7 +58,7 @@ class ArduinoIoTCloudTCP: public ArduinoIoTCloudClass
   public:
 
              ArduinoIoTCloudTCP();
-    virtual ~ArduinoIoTCloudTCP();
+    virtual ~ArduinoIoTCloudTCP() { }
 
 
     virtual void update        () override;
@@ -108,13 +108,13 @@ class ArduinoIoTCloudTCP: public ArduinoIoTCloudClass
 
     #ifdef BOARD_HAS_ECCX08
     ECCX08CertClass _eccx08_cert;
-    BearSSLClient* _sslClient;
+    BearSSLClient _sslClient;
     #elif defined(BOARD_ESP)
-    WiFiClientSecure* _sslClient;
+    WiFiClientSecure _sslClient;
     String _password;
     #endif
 
-    MqttClient* _mqttClient;
+    MqttClient _mqttClient;
 
     ArduinoIoTSynchronizationStatus _syncStatus;