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);
}
}
}
DiskLoc ExtentManager::getPrevRecord( const DiskLoc& loc ) const {
DiskLoc prev = getPrevRecordInExtent( loc );
if ( !prev.isNull() )
return prev;
// now traverse extents
Extent *e = extentFor(loc);
while ( 1 ) {
if ( e->xprev.isNull() )
return DiskLoc(); // end of collection
e = e->xprev.ext();
if ( !e->firstRecord.isNull() )
break;
// entire extent could be empty, keep looking
}
return e->firstRecord;
}
DiskLoc RecordStoreV1Base::getPrevRecord( const DiskLoc& loc ) const {
DiskLoc prev = getPrevRecordInExtent( loc );
if ( !prev.isNull() )
return prev;
// now traverse extents
Extent *e = _getExtent(_getExtentLocForRecord(loc));
while ( 1 ) {
if ( e->xprev.isNull() )
return DiskLoc(); // end of collection
e = _getExtent( e->xprev );
if ( !e->firstRecord.isNull() )
break;
// entire extent could be empty, keep looking
}
return e->lastRecord;
}
void RecordStoreV1Base::deleteRecord( OperationContext* txn, const DiskLoc& dl ) {
Record* todelete = recordFor( dl );
invariant( todelete->netLength() >= 4 ); // this is required for defensive code
/* remove ourself from the record next/prev chain */
{
if ( todelete->prevOfs() != DiskLoc::NullOfs ) {
DiskLoc prev = getPrevRecordInExtent( txn, dl );
Record* prevRecord = recordFor( prev );
txn->recoveryUnit()->writingInt( prevRecord->nextOfs() ) = todelete->nextOfs();
}
if ( todelete->nextOfs() != DiskLoc::NullOfs ) {
DiskLoc next = getNextRecord( txn, dl );
Record* nextRecord = recordFor( next );
txn->recoveryUnit()->writingInt( nextRecord->prevOfs() ) = todelete->prevOfs();
}
}
/* remove ourself from extent pointers */
{
DiskLoc extentLoc = todelete->myExtentLoc(dl);
Extent *e = _getExtent( txn, extentLoc );
if ( e->firstRecord == dl ) {
txn->recoveryUnit()->writing(&e->firstRecord);
if ( todelete->nextOfs() == DiskLoc::NullOfs )
e->firstRecord.Null();
else
e->firstRecord.set(dl.a(), todelete->nextOfs() );
}
if ( e->lastRecord == dl ) {
txn->recoveryUnit()->writing(&e->lastRecord);
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->recoveryUnit()->writingPtr(todelete, todelete->lengthWithHeaders() ),
0, todelete->lengthWithHeaders() );
}
else {
// this is defensive so we can detect if we are still using a location
// that was deleted
memset(txn->recoveryUnit()->writingPtr(todelete->data(), 4), 0xee, 4);
addDeletedRec(txn, dl);
}
}
}
