Status HashIndexCursor::seek(const BSONObj& position) {
//Use FieldRangeSet to parse the query into a vector of intervals
//These should be point-intervals if this cursor is ever used
//So the FieldInterval vector will be, e.g. <[1,1], [3,3], [6,6]>
FieldRangeSet frs( "" , position, true, true );
const vector<FieldInterval>& intervals = frs.range( _hashedField.c_str() ).intervals();
//Construct a new query based on the hashes of the previous point-intervals
//e.g. {a : {$in : [ hash(1) , hash(3) , hash(6) ]}}
BSONObjBuilder newQueryBuilder;
BSONObjBuilder inObj( newQueryBuilder.subobjStart( _hashedField ) );
BSONArrayBuilder inArray( inObj.subarrayStart("$in") );
vector<FieldInterval>::const_iterator i;
for( i = intervals.begin(); i != intervals.end(); ++i ){
if ( ! i->equality() ){
_oldCursor.reset(
BtreeCursor::make( nsdetails( _descriptor->parentNS()),
_descriptor->getOnDisk(),
BSON( "" << MINKEY ) ,
BSON( "" << MAXKEY ) ,
true ,
1 ) );
return Status::OK();
}
inArray.append(HashAccessMethod::makeSingleKey(i->_lower._bound, _seed, _hashVersion));
}
inArray.done();
inObj.done();
BSONObj newQuery = newQueryBuilder.obj();
// FieldRangeVector needs an IndexSpec so we make it one.
BSONObjBuilder specBuilder;
BSONObjIterator it(_descriptor->keyPattern());
while (it.more()) {
BSONElement e = it.next();
specBuilder.append(e.fieldName(), 1);
}
BSONObj spec = specBuilder.obj();
IndexSpec specForFRV(spec);
//Use the point-intervals of the new query to create a Btree cursor
FieldRangeSet newfrs( "" , newQuery , true, true );
shared_ptr<FieldRangeVector> newVector(
new FieldRangeVector( newfrs , specForFRV, 1 ) );
_oldCursor.reset(
BtreeCursor::make(nsdetails(_descriptor->parentNS()),
_descriptor->getOnDisk(),
newVector,
0,
1));
return Status::OK();
}
void S2SimpleCursor::seek(const BSONObj& query, const vector<GeoQuery>& regions) {
_nscanned = 0;
_matchTested = 0;
_geoTested = 0;
_fields = regions;
_seen = unordered_set<DiskLoc, DiskLoc::Hasher>();
BSONObjBuilder geoFieldsToNuke;
for (size_t i = 0; i < _fields.size(); ++i) {
geoFieldsToNuke.append(_fields[i].getField(), "");
}
// false means we want to filter OUT geoFieldsToNuke, not filter to include only that.
_filteredQuery = query.filterFieldsUndotted(geoFieldsToNuke.obj(), false);
// FieldRangeVector needs an IndexSpec so we make it one.
BSONObjBuilder specBuilder;
BSONObjIterator i(_descriptor->keyPattern());
while (i.more()) {
BSONElement e = i.next();
specBuilder.append(e.fieldName(), 1);
}
BSONObj spec = specBuilder.obj();
IndexSpec specForFRV(spec);
BSONObj frsObj;
BSONObjBuilder frsObjBuilder;
frsObjBuilder.appendElements(_filteredQuery);
S2RegionCoverer coverer;
for (size_t i = 0; i < _fields.size(); ++i) {
vector<S2CellId> cover;
double area = _fields[i].getRegion().GetRectBound().Area();
S2SearchUtil::setCoverLimitsBasedOnArea(area, &coverer, _params.coarsestIndexedLevel);
coverer.GetCovering(_fields[i].getRegion(), &cover);
uassert(16759, "No cover ARGH?!", cover.size() > 0);
_cellsInCover = cover.size();
BSONObj fieldRange = S2SearchUtil::coverAsBSON(cover, _fields[i].getField(),
_params.coarsestIndexedLevel);
frsObjBuilder.appendElements(fieldRange);
}
frsObj = frsObjBuilder.obj();
FieldRangeSet frs(_descriptor->parentNS().c_str(), frsObj, false, false);
shared_ptr<FieldRangeVector> frv(new FieldRangeVector(frs, specForFRV, 1));
_btreeCursor.reset(BtreeCursor::make(nsdetails(_descriptor->parentNS()),
_descriptor->getOnDisk(), frv, 0, 1));
next();
}
bool S2Cursor::ok() {
if (NULL == _btreeCursor.get()) {
// FieldRangeVector needs an IndexSpec so we make it one.
BSONObjBuilder specBuilder;
BSONObjIterator i(_keyPattern);
while (i.more()) {
BSONElement e = i.next();
specBuilder.append(e.fieldName(), 1);
}
BSONObj spec = specBuilder.obj();
IndexSpec specForFRV(spec);
// All the magic is in makeUnifiedFRS. See below.
// A lot of these arguments are opaque.
BSONObj frsObj;
if (!makeFRSObject(&frsObj)) { return false; }
FieldRangeSet frs(_details->parentNS().c_str(), frsObj, false, false);
shared_ptr<FieldRangeVector> frv(new FieldRangeVector(frs, specForFRV, 1));
_btreeCursor.reset(BtreeCursor::make(nsdetails(_details->parentNS()),
*_details, frv, 0, 1));
return advance();
}
return _btreeCursor->ok();
}
