// static
void ProjectionStage::getSimpleInclusionFields(const BSONObj& projObj,
FieldSet* includedFields) {
// The _id is included by default.
bool includeId = true;
// Figure out what fields are in the projection. TODO: we can get this from the
// ParsedProjection...modify that to have this type instead of a vector.
BSONObjIterator projObjIt(projObj);
while (projObjIt.more()) {
BSONElement elt = projObjIt.next();
// Must deal with the _id case separately as there is an implicit _id: 1 in the
// projection.
if (mongoutils::str::equals(elt.fieldName(), kIdField)
&& !elt.trueValue()) {
includeId = false;
continue;
}
includedFields->insert(elt.fieldNameStringData());
}
if (includeId) {
includedFields->insert(kIdField);
}
}
ProjectionStage::ProjectionStage(const ProjectionStageParams& params,
WorkingSet* ws,
PlanStage* child)
: _ws(ws),
_child(child),
_projImpl(params.projImpl) {
if (ProjectionStageParams::NO_FAST_PATH == _projImpl) {
_exec.reset(new ProjectionExec(params.projObj, params.fullExpression));
}
else {
// We shouldn't need the full expression if we're fast-pathing.
invariant(NULL == params.fullExpression);
_projObj = params.projObj;
// Sanity-check the input.
invariant(_projObj.isOwned());
invariant(!_projObj.isEmpty());
// The _id is included by default.
bool includeId = true;
// Figure out what fields are in the projection. TODO: we can get this from the
// ParsedProjection...modify that to have this type instead of a vector.
BSONObjIterator projObjIt(_projObj);
while (projObjIt.more()) {
BSONElement elt = projObjIt.next();
// Must deal with the _id case separately as there is an implicit _id: 1 in the
// projection.
if (mongoutils::str::equals(elt.fieldName(), kIdField)
&& !elt.trueValue()) {
includeId = false;
continue;
}
_includedFields.insert(elt.fieldNameStringData());
}
if (includeId) {
_includedFields.insert(kIdField);
}
// If we're pulling data out of one index we can pre-compute the indices of the fields
// in the key that we pull data from and avoid looking up the field name each time.
if (ProjectionStageParams::COVERED_ONE_INDEX == params.projImpl) {
// Sanity-check.
_coveredKeyObj = params.coveredKeyObj;
invariant(_coveredKeyObj.isOwned());
BSONObjIterator kpIt(_coveredKeyObj);
while (kpIt.more()) {
BSONElement elt = kpIt.next();
unordered_set<StringData, StringData::Hasher>::iterator fieldIt;
fieldIt = _includedFields.find(elt.fieldNameStringData());
if (_includedFields.end() == fieldIt) {
// Push an unused value on the back to keep _includeKey and _keyFieldNames
// in sync.
_keyFieldNames.push_back(StringData());
_includeKey.push_back(false);
}
else {
// If we are including this key field store its field name.
_keyFieldNames.push_back(*fieldIt);
_includeKey.push_back(true);
}
}
}
else {
invariant(ProjectionStageParams::SIMPLE_DOC == params.projImpl);
}
}
}
