void restore() override {
// Always do a full seek on restore. We cannot use our last position since index
// entries may have been inserted closer to our endpoint and we would need to move
// over them.
seekEndCursor();
if (_savedAtEnd) {
_isEOF = true;
return;
}
// Need to find our position from the root.
locate(_savedKey, _savedLoc);
_lastMoveWasRestore = _isEOF; // We weren't EOF but now are.
if (!_lastMoveWasRestore) {
// For standard (non-unique) indices, restoring to either a new key or a new record
// id means that the next key should be the one we just restored to.
//
// Cursors for unique indices should never return the same key twice, so we don't
// consider the restore as having moved the cursor position if the record id
// changes. In this case we use a null record id so that only the keys are compared.
auto savedLocToUse = _isUnique ? RecordId() : _savedLoc;
_lastMoveWasRestore =
(_data.value_comp().compare(*_it, {_savedKey, savedLocToUse}) != 0);
}
}
void setEndPosition(const BSONObj& key, bool inclusive) override {
if (key.isEmpty()) {
// This means scan to end of index.
_endState = boost::none;
return;
}
// NOTE: this uses the opposite min/max rules as a normal seek because a forward
// scan should land after the key if inclusive and before if exclusive.
_endState = EndState(stripFieldNames(key),
_forward == inclusive ? RecordId::max() : RecordId::min());
seekEndCursor();
}
void restore() override {
// Always do a full seek on restore. We cannot use our last position since index
// entries may have been inserted closer to our endpoint and we would need to move
// over them.
seekEndCursor();
if (_savedAtEnd) {
_isEOF = true;
return;
}
// Need to find our position from the root.
locate(_savedKey, _savedLoc);
_lastMoveWasRestore = _isEOF // We weren't EOF but now are.
|| _data.value_comp().compare(*_it, {_savedKey, _savedLoc}) != 0;
}