MQTTStatus_t MQTT_Connect()

in source/core_mqtt.c [1759:1852]

• 80 lines of code
• 11 McCabe index (conditional complexity)

MQTTStatus_t MQTT_Connect( MQTTContext_t * pContext,
                           const MQTTConnectInfo_t * pConnectInfo,
                           const MQTTPublishInfo_t * pWillInfo,
                           uint32_t timeoutMs,
                           bool * pSessionPresent )
{
    size_t remainingLength = 0UL, packetSize = 0UL;
    int32_t bytesSent;
    MQTTStatus_t status = MQTTSuccess;
    MQTTPacketInfo_t incomingPacket = { 0 };

    incomingPacket.type = ( uint8_t ) 0;

    if( ( pContext == NULL ) || ( pConnectInfo == NULL ) || ( pSessionPresent == NULL ) )
    {
        LogError( ( "Argument cannot be NULL: pContext=%p, "
                    "pConnectInfo=%p, pSessionPresent=%p.",
                    ( void * ) pContext,
                    ( void * ) pConnectInfo,
                    ( void * ) pSessionPresent ) );
        status = MQTTBadParameter;
    }

    if( status == MQTTSuccess )
    {
        /* Get MQTT connect packet size and remaining length. */
        status = MQTT_GetConnectPacketSize( pConnectInfo,
                                            pWillInfo,
                                            &remainingLength,
                                            &packetSize );
        LogDebug( ( "CONNECT packet size is %lu and remaining length is %lu.",
                    ( unsigned long ) packetSize,
                    ( unsigned long ) remainingLength ) );
    }

    if( status == MQTTSuccess )
    {
        status = MQTT_SerializeConnect( pConnectInfo,
                                        pWillInfo,
                                        remainingLength,
                                        &( pContext->networkBuffer ) );
    }

    if( status == MQTTSuccess )
    {
        bytesSent = sendPacket( pContext,
                                pContext->networkBuffer.pBuffer,
                                packetSize );

        if( bytesSent < ( int32_t ) packetSize )
        {
            LogError( ( "Transport send failed for CONNECT packet." ) );
            status = MQTTSendFailed;
        }
        else
        {
            LogDebug( ( "Sent %ld bytes of CONNECT packet.",
                        ( long int ) bytesSent ) );
        }
    }

    /* Read CONNACK from transport layer. */
    if( status == MQTTSuccess )
    {
        status = receiveConnack( pContext,
                                 timeoutMs,
                                 pConnectInfo->cleanSession,
                                 &incomingPacket,
                                 pSessionPresent );
    }

    if( status == MQTTSuccess )
    {
        /* Resend PUBRELs when reestablishing a session, or clear records for new sessions. */
        status = handleSessionResumption( pContext, *pSessionPresent );
    }

    if( status == MQTTSuccess )
    {
        LogInfo( ( "MQTT connection established with the broker." ) );
        pContext->connectStatus = MQTTConnected;
        /* Initialize keep-alive fields after a successful connection. */
        pContext->keepAliveIntervalSec = pConnectInfo->keepAliveSeconds;
        pContext->waitingForPingResp = false;
        pContext->pingReqSendTimeMs = 0U;
    }
    else
    {
        LogError( ( "MQTT connection failed with status = %s.",
                    MQTT_Status_strerror( status ) ) );
    }

    return status;
}