C++ DiskLoc::a方法代码示例

    void RecordStoreV1Base::deleteRecord( TransactionExperiment* txn, const DiskLoc& dl ) {

        Record* todelete = recordFor( dl );

        /* remove ourself from the record next/prev chain */
        {
            if ( todelete->prevOfs() != DiskLoc::NullOfs ) {
                DiskLoc prev = getPrevRecordInExtent( dl );
                Record* prevRecord = recordFor( prev );
                txn->writingInt( prevRecord->nextOfs() ) = todelete->nextOfs();
            }

            if ( todelete->nextOfs() != DiskLoc::NullOfs ) {
                DiskLoc next = getNextRecord( dl );
                Record* nextRecord = recordFor( next );
                txn->writingInt( nextRecord->prevOfs() ) = todelete->prevOfs();
            }
        }

        /* remove ourself from extent pointers */
        {
            Extent *e = txn->writing( _getExtent( _getExtentLocForRecord( dl ) ) );
            if ( e->firstRecord == dl ) {
                if ( todelete->nextOfs() == DiskLoc::NullOfs )
                    e->firstRecord.Null();
                else
                    e->firstRecord.set(dl.a(), todelete->nextOfs() );
            }
            if ( e->lastRecord == dl ) {
                if ( todelete->prevOfs() == DiskLoc::NullOfs )
                    e->lastRecord.Null();
                else
                    e->lastRecord.set(dl.a(), todelete->prevOfs() );
            }
        }

        /* add to the free list */
        {
            _details->incrementStats( txn, -1 * todelete->netLength(), -1 );

            if ( _isSystemIndexes ) {
                /* temp: if in system.indexes, don't reuse, and zero out: we want to be
                   careful until validated more, as IndexDetails has pointers
                   to this disk location.  so an incorrectly done remove would cause
                   a lot of problems.
                */
                memset( txn->writingPtr(todelete, todelete->lengthWithHeaders() ),
                        0, todelete->lengthWithHeaders() );
            }
            else {
                DEV {
                    unsigned long long *p = reinterpret_cast<unsigned long long *>( todelete->data() );
                    *txn->writing(p) = 0;
                }
                addDeletedRec(txn, dl);
            }
        }

    }

    /* deletes a record, just the pdfile portion -- no index cleanup, no cursor cleanup, etc.
       caller must check if capped
    */
    void DataFileMgr::_deleteRecord(NamespaceDetails *d, const StringData& ns, Record *todelete, const DiskLoc& dl) {
        /* remove ourself from the record next/prev chain */
        {
            if ( todelete->prevOfs() != DiskLoc::NullOfs )
                getDur().writingInt( todelete->getPrev(dl).rec()->nextOfs() ) = todelete->nextOfs();
            if ( todelete->nextOfs() != DiskLoc::NullOfs )
                getDur().writingInt( todelete->getNext(dl).rec()->prevOfs() ) = todelete->prevOfs();
        }

        /* remove ourself from extent pointers */
        {
            Extent *e = getDur().writing( todelete->myExtent(dl) );
            if ( e->firstRecord == dl ) {
                if ( todelete->nextOfs() == DiskLoc::NullOfs )
                    e->firstRecord.Null();
                else
                    e->firstRecord.set(dl.a(), todelete->nextOfs() );
            }
            if ( e->lastRecord == dl ) {
                if ( todelete->prevOfs() == DiskLoc::NullOfs )
                    e->lastRecord.Null();
                else
                    e->lastRecord.set(dl.a(), todelete->prevOfs() );
            }
        }

        /* add to the free list */
        {
            d->incrementStats( -1 * todelete->netLength(), -1 );

            if ( nsToCollectionSubstring(ns) == "system.indexes") {
                /* temp: if in system.indexes, don't reuse, and zero out: we want to be
                   careful until validated more, as IndexDetails has pointers
                   to this disk location.  so an incorrectly done remove would cause
                   a lot of problems.
                */
                memset(getDur().writingPtr(todelete, todelete->lengthWithHeaders() ), 0, todelete->lengthWithHeaders() );
            }
            else {
                DEV {
                    unsigned long long *p = reinterpret_cast<unsigned long long *>( todelete->data() );
                    *getDur().writing(p) = 0;
                    //DEV memset(todelete->data, 0, todelete->netLength()); // attempt to notice invalid reuse.
                }
                d->addDeletedRec((DeletedRecord*)todelete, dl);
            }
        }
    }

    /**
     * analyzeDiskStorage helper which processes a single record.
     */
    void processDeletedRecord(const DiskLoc& dl, const DeletedRecord* dr, const Extent* ex,
                              const AnalyzeParams& params, int bucketNum,
                              vector<DiskStorageData>& sliceData,
                              BSONArrayBuilder* deletedRecordsArrayBuilder) {

        killCurrentOp.checkForInterrupt();

        int extentOfs = ex->myLoc.getOfs();

        if (! (dl.a() == ex->myLoc.a() &&
               dl.getOfs() + dr->lengthWithHeaders() > extentOfs &&
               dl.getOfs() < extentOfs + ex->length) ) {

            return;
        }

        RecPos pos = RecPos::from(dl.getOfs(), dr->lengthWithHeaders(), extentOfs, params);
        bool spansRequestedArea = false;
        for (RecPos::SliceIterator it = pos.iterateSlices(); !it.end(); ++it) {

            DiskStorageData& slice = sliceData[it->sliceNum];
            slice.freeRecords[bucketNum] += it->ratioHere;
            spansRequestedArea = true;
        }

        if (deletedRecordsArrayBuilder != NULL && spansRequestedArea) {
            BSONObjBuilder(deletedRecordsArrayBuilder->subobjStart())
                .append("ofs", dl.getOfs() - extentOfs)
                .append("recBytes", dr->lengthWithHeaders());
        }
    }

    DiskLoc _repairExtent( Database* db , string ns, bool forward , DiskLoc eLoc ){
        LogIndentLevel lil;
        
        if ( eLoc.getOfs() <= 0 ){
            error() << "invalid extent ofs: " << eLoc.getOfs() << endl;
            return DiskLoc();
        }
        

        MongoDataFile * mdf = db->getFile( eLoc.a() );

        Extent * e = mdf->debug_getExtent( eLoc );
        if ( ! e->isOk() ){
            warning() << "Extent not ok magic: " << e->magic << " going to try to continue" << endl;
        }
        
        log() << "length:" << e->length << endl;
        
        LogIndentLevel lil2;
        
        DiskLoc loc = forward ? e->firstRecord : e->lastRecord;
        while ( ! loc.isNull() ){
            if ( loc.getOfs() <= 0 ){
                error() << "offset is 0 for record which should be impossible" << endl;
                break;
            }
            log() << loc << endl;
            Record* rec = loc.rec();
            log() << loc.obj() << endl;
            loc = forward ? rec->getNext( loc ) : rec->getPrev( loc );
        }
        return forward ? e->xnext : e->xprev;
        
    }

 // bypass standard alloc/insert routines to use the extent we want.
 static DiskLoc insert( DiskLoc ext, int i ) {
     BSONObjBuilder b;
     b.append( "a", i );
     BSONObj o = b.done();
     int len = o.objsize();
     Extent *e = ext.ext();
     int ofs;
     if ( e->lastRecord.isNull() )
         ofs = ext.getOfs() + ( e->extentData - (char *)e );
     else
         ofs = e->lastRecord.getOfs() + e->lastRecord.rec()->lengthWithHeaders;
     DiskLoc dl( ext.a(), ofs );
     Record *r = dl.rec();
     r->lengthWithHeaders = Record::HeaderSize + len;
     r->extentOfs = e->myLoc.getOfs();
     r->nextOfs = DiskLoc::NullOfs;
     r->prevOfs = e->lastRecord.isNull() ? DiskLoc::NullOfs : e->lastRecord.getOfs();
     memcpy( r->data, o.objdata(), len );
     if ( e->firstRecord.isNull() )
         e->firstRecord = dl;
     else
         e->lastRecord.rec()->nextOfs = ofs;
     e->lastRecord = dl;
     return dl;
 }

    void touchNs( const std::string& ns ) { 
        std::vector< touch_location > ranges;
        Client::ReadContext ctx(ns);
        {

            NamespaceDetails *nsd = nsdetails(ns.c_str());
            uassert( 16154, "namespace does not exist", nsd );
            
            for( DiskLoc L = nsd->firstExtent; !L.isNull(); L = L.ext()->xnext )  {
                MongoDataFile* mdf = cc().database()->getFile( L.a() );
                massert( 16238, "can't fetch extent file structure", mdf );
                touch_location tl;
                tl.fd = mdf->getFd();
                tl.offset = L.getOfs();
                tl.ext = L.ext();
                tl.length = tl.ext->length;
                
                ranges.push_back(tl);                
            }

        }
        LockMongoFilesShared lk;
        Lock::TempRelease tr;
        std::string progress_msg = "touch " + ns + " extents";
        ProgressMeterHolder pm( cc().curop()->setMessage( progress_msg.c_str() , ranges.size() ) );
        for ( std::vector< touch_location >::iterator it = ranges.begin(); it != ranges.end(); ++it ) {
            touch_pages( it->fd, it->offset, it->length, it->ext );
            pm.hit();
            killCurrentOp.checkForInterrupt(false);
        }
        pm.finished();
    }

    /**
     * analyzeDiskStorage helper which processes a single record.
     */
    void processRecord(const DiskLoc& dl, const DiskLoc& prevDl, const Record* r, int extentOfs,
                       const AnalyzeParams& params, vector<DiskStorageData>& sliceData,
                       BSONArrayBuilder* recordsArrayBuilder) {
        killCurrentOp.checkForInterrupt();

        BSONObj obj = dl.obj();
        int recBytes = r->lengthWithHeaders();
        double characteristicFieldValue = 0;
        bool hasCharacteristicField = extractCharacteristicFieldValue(obj, params,
                                                                      characteristicFieldValue);
        bool isLocatedBeforePrevious = dl.a() < prevDl.a();

        RecPos pos = RecPos::from(dl.getOfs(), recBytes, extentOfs, params);
        bool spansRequestedArea = false;
        for (RecPos::SliceIterator it = pos.iterateSlices(); !it.end(); ++it) {
            spansRequestedArea = true;
            DiskStorageData& slice = sliceData[it->sliceNum];
            slice.numEntries += it->ratioHere;
            slice.recBytes += it->sizeHere;
            slice.bsonBytes += static_cast<long long>(it->ratioHere * obj.objsize());
            if (hasCharacteristicField) {
                slice.characteristicCount += it->ratioHere;
                slice.characteristicSum += it->ratioHere * characteristicFieldValue;
            }
            if (isLocatedBeforePrevious) {
                slice.outOfOrderRecs += it->ratioHere;
            }
        }

        if (recordsArrayBuilder != NULL && spansRequestedArea) {
            DEV {
                int startsAt = dl.getOfs() - extentOfs;
                int endsAt = startsAt + recBytes;
                verify((startsAt < params.startOfs && endsAt > params.startOfs) ||
                       (startsAt < params.endOfs && endsAt >= params.endOfs) ||
                       (startsAt >= params.startOfs && endsAt < params.endOfs));
            }
            BSONObjBuilder recordBuilder(recordsArrayBuilder->subobjStart());
            recordBuilder.append("ofs", dl.getOfs() - extentOfs);
            recordBuilder.append("recBytes", recBytes);
            recordBuilder.append("bsonBytes", obj.objsize());
            recordBuilder.append("_id", obj["_id"]);
            if (hasCharacteristicField) {
                recordBuilder.append("characteristic", characteristicFieldValue);
            }
            recordBuilder.doneFast();
        }

    /* combine adjacent deleted records *for the current extent* of the capped collection

       this is O(n^2) but we call it for capped tables where typically n==1 or 2!
       (or 3...there will be a little unused sliver at the end of the extent.)
    */
    void NamespaceDetails::compact() {
        DDD( "NamespaceDetails::compact enter" );
        verify( isCapped() );
        
        vector<DiskLoc> drecs;
        
        // Pull out capExtent's DRs from deletedList
        DiskLoc i = cappedFirstDeletedInCurExtent();
        for (; !i.isNull() && inCapExtent( i ); i = i.drec()->nextDeleted() ) {
            DDD( "\t" << i );
            drecs.push_back( i );
        }

        getDur().writingDiskLoc( cappedFirstDeletedInCurExtent() ) = i;
        
        std::sort( drecs.begin(), drecs.end() );
        DDD( "\t drecs.size(): " << drecs.size() );

        vector<DiskLoc>::const_iterator j = drecs.begin();
        verify( j != drecs.end() );
        DiskLoc a = *j;
        while ( 1 ) {
            j++;
            if ( j == drecs.end() ) {
                DDD( "\t compact adddelrec" );
                addDeletedRec(a.drec(), a);
                break;
            }
            DiskLoc b = *j;
            while ( a.a() == b.a() && a.getOfs() + a.drec()->lengthWithHeaders() == b.getOfs() ) {
                // a & b are adjacent.  merge.
                getDur().writingInt( a.drec()->lengthWithHeaders() ) += b.drec()->lengthWithHeaders();
                j++;
                if ( j == drecs.end() ) {
                    DDD( "\t compact adddelrec2" );
                    addDeletedRec(a.drec(), a);
                    return;
                }
                b = *j;
            }
            DDD( "\t compact adddelrec3" );
            addDeletedRec(a.drec(), a);
            a = b;
        }

    }

    DiskLoc ExtentManager::getNextRecordInExtent( const DiskLoc& loc ) const {
        int nextOffset = recordFor( loc )->nextOfs();

        if ( nextOffset == DiskLoc::NullOfs )
            return DiskLoc();

        fassert( 16967, abs(nextOffset) >= 8 ); // defensive
        return DiskLoc( loc.a(), nextOffset );
    }

    DiskLoc RecordStoreV1Base::getNextRecordInExtent( const DiskLoc& loc ) const {
        int nextOffset = recordFor( loc )->nextOfs();

        if ( nextOffset == DiskLoc::NullOfs )
            return DiskLoc();

        fassert( 17441, abs(nextOffset) >= 8 ); // defensive
        return DiskLoc( loc.a(), nextOffset );
    }

    DiskLoc ExtentManager::getPrevRecordInExtent( const DiskLoc& loc ) const {
        int prevOffset = recordFor( loc )->prevOfs();

        if ( prevOffset == DiskLoc::NullOfs )
            return DiskLoc();

        fassert( 16968, abs(prevOffset) >= 8 ); // defensive
        return DiskLoc( loc.a(), prevOffset );
    }

    DiskLoc RecordStoreV1Base::getPrevRecordInExtent( OperationContext* txn, const DiskLoc& loc ) const {
        int prevOffset = recordFor( loc )->prevOfs();

        if ( prevOffset == DiskLoc::NullOfs )
            return DiskLoc();

        fassert( 17442, abs(prevOffset) >= 8 ); // defensive
        DiskLoc result( loc.a(), prevOffset );
        return result;
    }

    /* combine adjacent deleted records *for the current extent* of the capped collection
     
       this is O(n^2) but we call it for capped tables where typically n==1 or 2!
       (or 3...there will be a little unused sliver at the end of the extent.)
    */
    void NamespaceDetails::compact() {
        assert(capped);

        list<DiskLoc> drecs;

        // Pull out capExtent's DRs from deletedList
        DiskLoc i = cappedFirstDeletedInCurExtent();
        for (; !i.isNull() && inCapExtent( i ); i = i.drec()->nextDeleted )
            drecs.push_back( i );

        getDur().writingDiskLoc( cappedFirstDeletedInCurExtent() ) = i;

        // This is the O(n^2) part.
        drecs.sort();

        list<DiskLoc>::iterator j = drecs.begin();
        assert( j != drecs.end() );
        DiskLoc a = *j;
        while ( 1 ) {
            j++;
            if ( j == drecs.end() ) {
                DEBUGGING out() << "TEMP: compact adddelrec\n";
                addDeletedRec(a.drec(), a);
                break;
            }
            DiskLoc b = *j;
            while ( a.a() == b.a() && a.getOfs() + a.drec()->lengthWithHeaders == b.getOfs() ) {
                // a & b are adjacent.  merge.
                getDur().writingInt( a.drec()->lengthWithHeaders ) += b.drec()->lengthWithHeaders;
                j++;
                if ( j == drecs.end() ) {
                    DEBUGGING out() << "temp: compact adddelrec2\n";
                    addDeletedRec(a.drec(), a);
                    return;
                }
                b = *j;
            }
            DEBUGGING out() << "temp: compact adddelrec3\n";
            addDeletedRec(a.drec(), a);
            a = b;
        }
    }

    bool NamespaceDetails::inCapExtent( const DiskLoc &dl ) const {
        invariant( !dl.isNull() );

        if ( dl.a() != _capExtent.a() )
            return false;

        if ( dl.getOfs() < _capExtent.getOfs() )
            return false;

        const Extent* e = theCapExtent();
        int end = _capExtent.getOfs() + e->length;
        return dl.getOfs() <= end;
    }

 void DiskLoc56Bit::operator=(const DiskLoc& loc) {
     ofs = loc.getOfs();
     int la = loc.a();
     invariant( la <= 0xffffff ); // must fit in 3 bytes
     if( la < 0 ) {
         if ( la != -1 ) {
             log() << "btree diskloc isn't negative 1: " << la << std::endl;
             invariant ( la == -1 );
         }
         la = 0;
         ofs = OurNullOfs;
     }
     memcpy(_a, &la, 3); // endian
 }