static int UpdateMqttConnectionStateIfNeeded()

in iothub_client/src/iothubtransport_mqtt_common.c [2797:2919]
113 lines of code
26 McCabe index (conditional complexity)

static int UpdateMqttConnectionStateIfNeeded(PMQTTTRANSPORT_HANDLE_DATA transport_data)
{
    int result = 0;

    // Make sure we're not destroying the object
    if (!transport_data->isDestroyCalled)
    {
        RETRY_ACTION retry_action = RETRY_ACTION_RETRY_LATER;

        if (transport_data->mqttClientStatus == MQTT_CLIENT_STATUS_NOT_CONNECTED && transport_data->isRecoverableError)
        {
            // Note: in case retry_control_should_retry fails, the reconnection shall be attempted anyway (defaulting to policy IOTHUB_CLIENT_RETRY_IMMEDIATE).
            if (!transport_data->conn_attempted || retry_control_should_retry(transport_data->retry_control_handle, &retry_action) != 0 || retry_action == RETRY_ACTION_RETRY_NOW)
            {
                if (tickcounter_get_current_ms(transport_data->msgTickCounter, &transport_data->connectTick) != 0)
                {
                    transport_data->connectFailCount++;
                    result = MU_FAILURE;
                }
                else
                {
                    ResetConnectionIfNecessary(transport_data);

                    if (SendMqttConnectMsg(transport_data) != 0)
                    {
                        transport_data->connectFailCount++;
                        result = MU_FAILURE;
                    }
                    else
                    {
                        transport_data->mqttClientStatus = MQTT_CLIENT_STATUS_CONNECTING;
                        transport_data->connectFailCount = 0;
                        result = 0;
                    }
                }
            }
            else if (retry_action == RETRY_ACTION_STOP_RETRYING)
            {
                // send callback if retry expired
                if (!transport_data->isRetryExpiredCallbackCalled)
                {
                    transport_data->transport_callbacks.connection_status_cb(IOTHUB_CLIENT_CONNECTION_UNAUTHENTICATED, IOTHUB_CLIENT_CONNECTION_RETRY_EXPIRED, transport_data->transport_ctx);
                    transport_data->isRetryExpiredCallbackCalled = true;
                }
                result = MU_FAILURE;
            }
            else if (retry_action == RETRY_ACTION_RETRY_LATER)
            {
                result = MU_FAILURE;
            }
        }
        else if (transport_data->mqttClientStatus == MQTT_CLIENT_STATUS_EXECUTE_DISCONNECT)
        {
            // Need to disconnect from client
            DisconnectFromClient(transport_data);
            result = 0;
        }
        else if (transport_data->mqttClientStatus == MQTT_CLIENT_STATUS_CONNECTING)
        {
            tickcounter_ms_t current_time;
            if (tickcounter_get_current_ms(transport_data->msgTickCounter, &current_time) != 0)
            {
                LogError("failed verifying MQTT_CLIENT_STATUS_CONNECTING timeout");
                result = MU_FAILURE;
            }
            else if ((current_time - transport_data->mqtt_connect_time) / 1000 > transport_data->connect_timeout_in_sec)
            {
                LogError("mqtt_client timed out waiting for CONNACK: disconnecting MQTT connection");
                transport_data->currPacketState = PACKET_TYPE_ERROR;
                DisconnectFromClient(transport_data);
                result = MU_FAILURE;
            }
        }
        else if (transport_data->mqttClientStatus == MQTT_CLIENT_STATUS_CONNECTED)
        {
            // We are connected and not being closed, so does SAS need to reconnect?
            tickcounter_ms_t current_time;
            if (tickcounter_get_current_ms(transport_data->msgTickCounter, &current_time) != 0)
            {
                transport_data->connectFailCount++;
                result = MU_FAILURE;
            }
            else
            {
                IOTHUB_CREDENTIAL_TYPE cred_type = IoTHubClient_Auth_Get_Credential_Type(transport_data->authorization_module);
                // If the credential type is not an x509 certificate then we shall renew the Sas_Token
                if (cred_type != IOTHUB_CREDENTIAL_TYPE_X509 && cred_type != IOTHUB_CREDENTIAL_TYPE_X509_ECC)
                {
                    uint64_t sas_token_expiry = IoTHubClient_Auth_Get_SasToken_Expiry(transport_data->authorization_module);
                    if ((current_time - transport_data->mqtt_connect_time) / 1000 > (sas_token_expiry*SAS_REFRESH_MULTIPLIER))
                    {
                        LogInfo("Disconnecting MQTT connection because SAS token expired.");
                        DisconnectFromClient(transport_data);

                        transport_data->transport_callbacks.connection_status_cb(IOTHUB_CLIENT_CONNECTION_UNAUTHENTICATED, IOTHUB_CLIENT_CONNECTION_EXPIRED_SAS_TOKEN, transport_data->transport_ctx);
                        transport_data->currPacketState = UNKNOWN_TYPE;
                        if (transport_data->topic_MqttMessage != NULL)
                        {
                            transport_data->topics_ToSubscribe |= SUBSCRIBE_TELEMETRY_TOPIC;
                        }
                        if (transport_data->topic_GetState != NULL)
                        {
                            transport_data->topics_ToSubscribe |= SUBSCRIBE_GET_REPORTED_STATE_TOPIC;
                        }
                        if (transport_data->topic_NotifyState != NULL)
                        {
                            transport_data->topics_ToSubscribe |= SUBSCRIBE_NOTIFICATION_STATE_TOPIC;
                        }
                        if (transport_data->topic_DeviceMethods != NULL)
                        {
                            transport_data->topics_ToSubscribe |= SUBSCRIBE_DEVICE_METHOD_TOPIC;
                        }
                        if (transport_data->topic_InputQueue != NULL)
                        {
                            transport_data->topics_ToSubscribe |= SUBSCRIBE_INPUT_QUEUE_TOPIC;
                        }
                    }
                }
            }
        }
    }
    return result;
}