pair<vector<BSONObj>, vector<BSONObj>> IndexAccessMethod::setDifference(const BSONObjSet& left,
const BSONObjSet& right) {
// Two iterators to traverse the two sets in sorted order.
auto leftIt = left.begin();
auto rightIt = right.begin();
vector<BSONObj> onlyLeft;
vector<BSONObj> onlyRight;
while (leftIt != left.end() && rightIt != right.end()) {
const int cmp = leftIt->woCompare(*rightIt);
if (cmp == 0) {
// 'leftIt' and 'rightIt' compare equal using woCompare(), but may not be identical,
// which should result in an index change.
if (!leftIt->binaryEqual(*rightIt)) {
onlyLeft.push_back(*leftIt);
onlyRight.push_back(*rightIt);
}
++leftIt;
++rightIt;
continue;
} else if (cmp > 0) {
onlyRight.push_back(*rightIt);
++rightIt;
} else {
onlyLeft.push_back(*leftIt);
++leftIt;
}
}
// Add the rest of 'left' to 'onlyLeft', and the rest of 'right' to 'onlyRight', if any.
onlyLeft.insert(onlyLeft.end(), leftIt, left.end());
onlyRight.insert(onlyRight.end(), rightIt, right.end());
return {std::move(onlyLeft), std::move(onlyRight)};
}
bool InMatchExpression::equivalent(const MatchExpression* other) const {
if (matchType() != other->matchType()) {
return false;
}
const InMatchExpression* realOther = static_cast<const InMatchExpression*>(other);
if (path() != realOther->path()) {
return false;
}
if (_hasNull != realOther->_hasNull) {
return false;
}
if (_regexes.size() != realOther->_regexes.size()) {
return false;
}
for (size_t i = 0; i < _regexes.size(); ++i) {
if (!_regexes[i]->equivalent(realOther->_regexes[i].get())) {
return false;
}
}
if (!CollatorInterface::collatorsMatch(_collator, realOther->_collator)) {
return false;
}
// We use an element-wise comparison to check equivalence of '_equalitySet'. Unfortunately, we
// can't use BSONElementSet::operator==(), as it does not use the comparator object the set is
// initialized with (and as such, it is not collation-aware).
if (_equalitySet.size() != realOther->_equalitySet.size()) {
return false;
}
auto thisEqIt = _equalitySet.begin();
auto otherEqIt = realOther->_equalitySet.begin();
for (; thisEqIt != _equalitySet.end(); ++thisEqIt, ++otherEqIt) {
const bool considerFieldName = false;
if (thisEqIt->woCompare(*otherEqIt, considerFieldName, _collator)) {
return false;
}
}
invariant(otherEqIt == realOther->_equalitySet.end());
return true;
}
