OtaErr_t requestFileBlock_Mqtt()

in source/ota_mqtt.c [1074:1174]

• 77 lines of code
• 4 McCabe index (conditional complexity)

OtaErr_t requestFileBlock_Mqtt( OtaAgentContext_t * pAgentCtx )
{
    OtaErr_t result = OtaErrRequestFileBlockFailed;
    OtaMqttStatus_t mqttStatus = OtaMqttSuccess;
    size_t msgSizeFromStream = 0;
    uint32_t blockSize = OTA_FILE_BLOCK_SIZE;
    uint32_t numBlocks = 0;
    uint32_t bitmapLen = 0;
    uint32_t msgSizeToPublish = 0;
    uint32_t topicLen = 0;
    bool cborEncodeRet = false;
    char pMsg[ OTA_REQUEST_MSG_MAX_SIZE ];

    /* This buffer is used to store the generated MQTT topic. The static size
     * is calculated from the template and the corresponding parameters. */
    char pTopicBuffer[ TOPIC_GET_STREAM_BUFFER_SIZE ];
    const OtaFileContext_t * pFileContext = NULL;

    /* NULL-terminated list of topic string parts. */
    const char * pTopicParts[] =
    {
        MQTT_API_THINGS,
        NULL, /* Thing Name not available at compile time, initialized below. */
        MQTT_API_STREAMS,
        NULL, /* Stream Name not available at compile time, initialized below. */
        MQTT_API_GET_CBOR,
        NULL
    };

    assert( pAgentCtx != NULL );

    /* Suppress warnings about unused variables. */
    ( void ) pOtaGetStreamTopicTemplate;

    /* Get the current file context. */
    pFileContext = &( pAgentCtx->fileContext );

    pTopicParts[ 1 ] = ( const char * ) pAgentCtx->pThingName;
    pTopicParts[ 3 ] = ( const char * ) pFileContext->pStreamName;

    /* Reset number of blocks requested. */
    pAgentCtx->numOfBlocksToReceive = otaconfigMAX_NUM_BLOCKS_REQUEST;

    numBlocks = ( pFileContext->fileSize + ( OTA_FILE_BLOCK_SIZE - 1U ) ) >> otaconfigLOG2_FILE_BLOCK_SIZE;
    bitmapLen = ( numBlocks + ( BITS_PER_BYTE - 1U ) ) >> LOG2_BITS_PER_BYTE;

    cborEncodeRet = OTA_CBOR_Encode_GetStreamRequestMessage( ( uint8_t * ) pMsg,
                                                             sizeof( pMsg ),
                                                             &msgSizeFromStream,
                                                             OTA_CLIENT_TOKEN,
                                                             ( int32_t ) pFileContext->serverFileID,
                                                             ( int32_t ) blockSize,
                                                             0,
                                                             pFileContext->pRxBlockBitmap,
                                                             bitmapLen,
                                                             ( int32_t ) otaconfigMAX_NUM_BLOCKS_REQUEST );

    if( cborEncodeRet == true )
    {
        msgSizeToPublish = ( uint32_t ) msgSizeFromStream;

        /* Try to build the dynamic data REQUEST topic to publish to. */

        topicLen = ( uint32_t ) stringBuilder(
            pTopicBuffer,
            sizeof( pTopicBuffer ),
            pTopicParts );

        /* The buffer is static and the size is calculated to fit. */
        assert( ( topicLen > 0U ) && ( topicLen < sizeof( pTopicBuffer ) ) );

        mqttStatus = pAgentCtx->pOtaInterface->mqtt.publish( pTopicBuffer,
                                                             ( uint16_t ) topicLen,
                                                             &pMsg[ 0 ],
                                                             msgSizeToPublish,
                                                             0 );

        if( mqttStatus == OtaMqttSuccess )
        {
            LogInfo( ( "Published to MQTT topic to request the next block: "
                       "topic=%s",
                       pTopicBuffer ) );
            result = OtaErrNone;
        }
        else
        {
            LogError( ( "Failed to publish MQTT message: "
                        "publish returned error: "
                        "OtaMqttStatus_t=%s",
                        OTA_MQTT_strerror( mqttStatus ) ) );
        }
    }
    else
    {
        result = OtaErrFailedToEncodeCbor;
        LogError( ( "Failed to CBOR encode stream request message: "
                    "OTA_CBOR_Encode_GetStreamRequestMessage returned error." ) );
    }

    return result;
}