IndexCursor::IndexCursor( Collection *cl, const IndexDetails &idx,
const BSONObj &startKey, const BSONObj &endKey,
bool endKeyInclusive, int direction, int numWanted ) :
_cl(cl),
_idx(idx),
_ordering(Ordering::make(_idx.keyPattern())),
_startKey(startKey),
_endKey(endKey),
_endKeyInclusive(endKeyInclusive),
_multiKey(_cl->isMultikey(_cl->idxNo(_idx))),
_direction(direction),
_bounds(),
_boundsMustMatch(true),
_nscanned(0),
_nscannedObjects(0),
_prelock(!cc().opSettings().getJustOne() && numWanted == 0),
_cursor(_idx, cursor_flags()),
_tailable(false),
_ok(false),
_getf_iteration(0)
{
verify( _cl != NULL );
TOKULOG(3) << toString() << ": constructor: bounds " << prettyIndexBounds() << endl;
DBC* cursor = _cursor.dbc();
cursor->c_set_check_interrupt_callback(cursor, cursor_check_interrupt, &_interrupt_extra);
initializeDBC();
}
IndexCursor::IndexCursor( Collection *cl, const IndexDetails &idx,
const shared_ptr< FieldRangeVector > &bounds,
int singleIntervalLimit, int direction, int numWanted ) :
_cl(cl),
_idx(idx),
_ordering(Ordering::make(_idx.keyPattern())),
_startKey(),
_endKey(),
_endKeyInclusive(true),
_multiKey(_cl->isMultikey(_cl->idxNo(_idx))),
_direction(direction),
_bounds(bounds),
_boundsMustMatch(true),
_nscanned(0),
_nscannedObjects(0),
_prelock(!cc().opSettings().getJustOne() && numWanted == 0),
_cursor(_idx, cursor_flags()),
_tailable(false),
_ok(false),
_getf_iteration(0)
{
verify( _cl != NULL );
_boundsIterator.reset( new FieldRangeVectorIterator( *_bounds , singleIntervalLimit ) );
_boundsIterator->prepDive();
_startKey = _bounds->startKey();
_endKey = _bounds->endKey();
_endKeyInclusive = _bounds->endKeyInclusive();
TOKULOG(3) << toString() << ": constructor: bounds " << prettyIndexBounds() << endl;
DBC* cursor = _cursor.dbc();
cursor->c_set_check_interrupt_callback(cursor, cursor_check_interrupt, &_interrupt_extra);
initializeDBC();
// Fairly bad hack:
//
// Primary keys are not skipped properly when a non-inclusive start bound is specified.
// See IndexCursor::skipToNextKey()
//
// Do a single advance here - the PK is unique so the next key is guaranteed to be
// strictly greater than the start key. We have to play games with _nscanned because
// advance()'s checkCurrentAgainstBounds() is going to increment it by 1 (we don't want that).
if (ok() && _cl->isPKIndex(_idx) && !_bounds->startKeyInclusive() && _currKey == _startKey) {
const long long oldNScanned = _nscanned;
advance();
verify(oldNScanned <= _nscanned);
_nscanned = oldNScanned;
}
DEV {
// At this point, the current key should be consistent with
// _startKey and _bounds->startKeyInclusive()
if (ok() && !_bounds->startKeyInclusive()) {
if (forward()) {
verify(_currKey.woCompare(_startKey, _ordering) > 0);
} else {
verify(_currKey.woCompare(_startKey, _ordering) < 0);
}
}
}
}