RPRIVATE
RVOID
    dnsUmDiffThread
    (
        rEvent isTimeToStop
    )
{
    rSequence notif = NULL;
    rBlob snapCur = NULL;
    rBlob snapPrev = NULL;
    _dnsRecord rec = { 0 };
    _dnsRecord* pCurRec = NULL;
    RU32 i = 0;
    LibOsPerformanceProfile perfProfile = { 0 };
    
#ifdef RPAL_PLATFORM_WINDOWS
    PDNSCACHEENTRY pDnsEntry = NULL;
    PDNSCACHEENTRY pPrevDnsEntry = NULL;
#endif

    perfProfile.enforceOnceIn = 1;
    perfProfile.sanityCeiling = MSEC_FROM_SEC( 10 );
    perfProfile.lastTimeoutValue = 100;
    perfProfile.targetCpuPerformance = 0;
    perfProfile.globalTargetCpuPerformance = GLOBAL_CPU_USAGE_TARGET;
    perfProfile.timeoutIncrementPerSec = 1;

    while( !rEvent_wait( isTimeToStop, 0 ) )
    {
        if( kAcq_isAvailable() )
        {
            // If kernel acquisition becomes available, try kernel again.
            return;
        }

        libOs_timeoutWithProfile( &perfProfile, FALSE, isTimeToStop );

        if( NULL != ( snapCur = rpal_blob_create( 0, 10 * sizeof( rec ) ) ) )
        {
#ifdef RPAL_PLATFORM_WINDOWS
            if( TRUE == getCache( &pDnsEntry ) )
            {
                while( NULL != pDnsEntry )
                {
                    rec.flags = pDnsEntry->dwFlags;
                    rec.type = pDnsEntry->wType;
                    if( NULL != ( rec.name = rpal_string_strdup( pDnsEntry->pszName ) ) )
                    {
                        rpal_blob_add( snapCur, &rec, sizeof( rec ) );
                    }

                    pPrevDnsEntry = pDnsEntry;
                    pDnsEntry = pDnsEntry->pNext;

                    freeCacheEntry( pPrevDnsEntry->pszName, DnsFreeFlat );
                    freeCacheEntry( pPrevDnsEntry, DnsFreeFlat );
                }

                rpal_sort_array( rpal_blob_getBuffer( snapCur ), 
                                 rpal_blob_getSize( snapCur ) / sizeof( rec ), 
                                 sizeof( rec ), 
                                 _cmpDns );
            }
#elif defined( RPAL_PLATFORM_MACOSX )
            rpal_thread_sleep( MSEC_FROM_SEC( 2 ) );
#endif

            // Do a general diff of the snapshots to find new entries.
            if( NULL != snapPrev )
            {
                i = 0;
                while( !rEvent_wait( isTimeToStop, 0 ) &&
                       NULL != ( pCurRec = rpal_blob_arrElem( snapCur, sizeof( rec ), i++ ) ) )
                {
                    if( -1 == rpal_binsearch_array( rpal_blob_getBuffer( snapPrev ), 
                                                    rpal_blob_getSize( snapPrev ) / sizeof( rec ), 
                                                    sizeof( rec ), 
                                                    pCurRec,
                                                    (rpal_ordering_func)_cmpDns ) )
                    {
                        if( NULL != ( notif = rSequence_new() ) )
                        {
                            rSequence_addSTRINGN( notif, RP_TAGS_DOMAIN_NAME, pCurRec->name );
                            rSequence_addRU16( notif, RP_TAGS_DNS_TYPE, pCurRec->type );
                            rSequence_addRU32( notif, RP_TAGS_DNS_FLAGS, pCurRec->flags );
                            hbs_timestampEvent( notif, 0 );

                            hbs_publish( RP_TAGS_NOTIFICATION_DNS_REQUEST, notif );

                            rSequence_free( notif );
                        }
                    }
                }
            }
        }

        if( NULL != snapPrev )
        {
            _freeRecords( snapPrev );
            rpal_blob_free( snapPrev );
            snapPrev = NULL;
        }

        snapPrev = snapCur;
        snapCur = NULL;

        libOs_timeoutWithProfile( &perfProfile, TRUE, isTimeToStop );
    }

    if( NULL != snapPrev )
    {
        _freeRecords( snapPrev );
        rpal_blob_free( snapPrev );
        snapPrev = NULL;
    }
}
static 
RPVOID
    dnsDiffThread
    (
        rEvent isTimeToStop,
        RPVOID ctx
    )
{
    RU32 nThLoop = 0;
    RU32 currentTimeout = 0;
    rSequence notif = NULL;
    rBlob snapCur = NULL;
    rBlob snapPrev = NULL;
    _dnsRecord rec = { 0 };
    _dnsRecord* pCurRec = NULL;
    _dnsRecord* pPrevRec = NULL;
    RU32 i = 0;
    RU32 j = 0;
    RBOOL isNew = FALSE;
    
#ifdef RPAL_PLATFORM_WINDOWS
    PDNSCACHEENTRY pDnsEntry = NULL;
    PDNSCACHEENTRY pPrevDnsEntry = NULL;
#endif

    UNREFERENCED_PARAMETER( ctx );

    while( !rEvent_wait( isTimeToStop, currentTimeout ) )
    {
        if( NULL != ( snapCur = rpal_blob_create( 0, 10 * sizeof( rec ) ) ) )
        {
#ifdef RPAL_PLATFORM_WINDOWS
            if( TRUE == getCache( &pDnsEntry ) )
            {
                while( NULL != pDnsEntry )
                {
                    rec.flags = pDnsEntry->dwFlags;
                    rec.type = pDnsEntry->wType;
                    if( NULL != ( rec.name = rpal_string_strdupw( pDnsEntry->pszName ) ) )
                    {
                        rpal_blob_add( snapCur, &rec, sizeof( rec ) );
                    }

                    pPrevDnsEntry = pDnsEntry;
                    pDnsEntry = pDnsEntry->pNext;

                    freeCacheEntry( pPrevDnsEntry->pszName, DnsFreeFlat );
                    freeCacheEntry( pPrevDnsEntry, DnsFreeFlat );
                }
            }
#endif

            // Do a general diff of the snapshots to find new entries.
            if( NULL != snapPrev )
            {
                i = 0;
                while( NULL != ( pCurRec = rpal_blob_arrElem( snapCur, sizeof( rec ), i++ ) ) )
                {
                    isNew = TRUE;
                    j = 0;
                    while( NULL != ( pPrevRec = rpal_blob_arrElem( snapPrev, sizeof( rec ), j++ ) ) )
                    {
                        if( pCurRec->flags == pPrevRec->flags &&
                            pCurRec->type == pPrevRec->type &&
                            0 == rpal_string_strcmpw( pCurRec->name, pPrevRec->name ) )
                        {
                            isNew = FALSE;
                            break;
                        }
                    }

                    if( isNew &&
                        !rEvent_wait( isTimeToStop, 0 ) )
                    {
                        if( NULL != ( notif = rSequence_new() ) )
                        {
                            rSequence_addSTRINGW( notif, RP_TAGS_DOMAIN_NAME, pCurRec->name );
                            rSequence_addRU16( notif, RP_TAGS_DNS_TYPE, pCurRec->type );
                            rSequence_addRU32( notif, RP_TAGS_DNS_FLAGS, pCurRec->flags );
                            rSequence_addTIMESTAMP( notif, RP_TAGS_TIMESTAMP, rpal_time_getGlobal() );

                            notifications_publish( RP_TAGS_NOTIFICATION_DNS_REQUEST, notif );

                            rSequence_free( notif );
                        }
                    }
                }
            }
        }

        if( NULL != snapPrev )
        {
            _freeRecords( snapPrev );
            rpal_blob_free( snapPrev );
            snapPrev = NULL;
        }

        snapPrev = snapCur;
        snapCur = NULL;

        nThLoop++;
        if( 0 == nThLoop % 20 )
        {
            currentTimeout = libOs_getUsageProportionalTimeout( MSEC_FROM_SEC( 10 ) ) + MSEC_FROM_SEC( 5 );
        }

        rpal_thread_sleep( currentTimeout );
    }

    if( NULL != snapPrev )
    {
        _freeRecords( snapPrev );
        rpal_blob_free( snapPrev );
        snapPrev = NULL;
    }

    return NULL;
}