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);
}
}
}
void RecordStoreV1Base::_addRecordToRecListInExtent(OperationContext* txn,
Record *r,
DiskLoc loc) {
dassert( recordFor(loc) == r );
Extent *e = _getExtent( _getExtentLocForRecord( loc ) );
if ( e->lastRecord.isNull() ) {
*txn->recoveryUnit()->writing(&e->firstRecord) = loc;
*txn->recoveryUnit()->writing(&e->lastRecord) = loc;
r->prevOfs() = r->nextOfs() = DiskLoc::NullOfs;
}
else {
Record *oldlast = recordFor(e->lastRecord);
r->prevOfs() = e->lastRecord.getOfs();
r->nextOfs() = DiskLoc::NullOfs;
txn->recoveryUnit()->writingInt(oldlast->nextOfs()) = loc.getOfs();
*txn->recoveryUnit()->writing(&e->lastRecord) = loc;
}
}
DiskLoc RecordStoreV1Base::getNextRecord( const DiskLoc& loc ) const {
DiskLoc next = getNextRecordInExtent( loc );
if ( !next.isNull() )
return next;
// now traverse extents
Extent* e = _getExtent( _getExtentLocForRecord(loc) );
while ( 1 ) {
if ( e->xnext.isNull() )
return DiskLoc(); // end of collection
e = _getExtent( e->xnext );
if ( !e->firstRecord.isNull() )
break;
// entire extent could be empty, keep looking
}
return e->firstRecord;
}
DiskLoc RecordStoreV1Base::getPrevRecord(OperationContext* txn, const DiskLoc& loc) const {
DiskLoc prev = getPrevRecordInExtent(txn, loc);
if (!prev.isNull()) {
return prev;
}
// now traverse extents
Extent* e = _getExtent(txn, _getExtentLocForRecord(txn, loc));
while (1) {
if (e->xprev.isNull())
return DiskLoc(); // end of collection
e = _getExtent(txn, e->xprev);
if (!e->firstRecord.isNull())
break;
// entire extent could be empty, keep looking
}
return e->lastRecord;
}