AzureIoTResult_t AzureIoTHubClient_SubscribeCloudToDeviceMessage()

in source/azure_iot_hub_client.c [933:984]
47 lines of code
5 McCabe index (conditional complexity)

AzureIoTResult_t AzureIoTHubClient_SubscribeCloudToDeviceMessage( AzureIoTHubClient_t * pxAzureIoTHubClient,
                                                                  AzureIoTHubClientCloudToDeviceMessageCallback_t xCallback,
                                                                  void * prvCallbackContext,
                                                                  uint32_t ulTimeoutMilliseconds )
{
    AzureIoTMQTTSubscribeInfo_t xMqttSubscription = { 0 };
    AzureIoTMQTTResult_t xMQTTResult;
    AzureIoTResult_t xResult;
    uint16_t usSubscribePacketIdentifier;
    AzureIoTHubClientReceiveContext_t * pxContext;

    if( ( pxAzureIoTHubClient == NULL ) ||
        ( xCallback == NULL ) )
    {
        AZLogError( ( "AzureIoTHubClient_SubscribeCloudToDeviceMessage failed: invalid argument" ) );
        xResult = eAzureIoTErrorInvalidArgument;
    }
    else
    {
        pxContext = &pxAzureIoTHubClient->_internal.xReceiveContext[ azureiothubRECEIVE_CONTEXT_INDEX_C2D ];
        xMqttSubscription.xQoS = eAzureIoTMQTTQoS1;
        xMqttSubscription.pcTopicFilter = ( const uint8_t * ) AZ_IOT_HUB_CLIENT_C2D_SUBSCRIBE_TOPIC;
        xMqttSubscription.usTopicFilterLength = ( uint16_t ) sizeof( AZ_IOT_HUB_CLIENT_C2D_SUBSCRIBE_TOPIC ) - 1;
        usSubscribePacketIdentifier = AzureIoTMQTT_GetPacketId( &( pxAzureIoTHubClient->_internal.xMQTTContext ) );

        AZLogDebug( ( "Attempting to subscribe to the MQTT topic: %s", AZ_IOT_HUB_CLIENT_C2D_SUBSCRIBE_TOPIC ) );

        if( ( xMQTTResult = AzureIoTMQTT_Subscribe( &( pxAzureIoTHubClient->_internal.xMQTTContext ),
                                                    &xMqttSubscription, 1, usSubscribePacketIdentifier ) ) != eAzureIoTMQTTSuccess )
        {
            AZLogError( ( "Cloud to device subscribe failed: MQTT error=0x%08x", xMQTTResult ) );
            xResult = eAzureIoTErrorSubscribeFailed;
        }
        else
        {
            pxContext->_internal.usState = azureiothubTOPIC_SUBSCRIBE_STATE_SUB;
            pxContext->_internal.usMqttSubPacketID = usSubscribePacketIdentifier;
            pxContext->_internal.pxProcessFunction = prvAzureIoTHubClientC2DProcess;
            pxContext->_internal.callbacks.xCloudToDeviceMessageCallback = xCallback;
            pxContext->_internal.pvCallbackContext = prvCallbackContext;

            if( ( xResult = prvWaitForSubAck( pxAzureIoTHubClient, pxContext,
                                              ulTimeoutMilliseconds ) ) != eAzureIoTSuccess )
            {
                AZLogError( ( "Wait for cloud to device sub ack failed : error=0x%08x", xResult ) );
                memset( pxContext, 0, sizeof( AzureIoTHubClientReceiveContext_t ) );
            }
        }
    }

    return xResult;
}