// Scan retrieves the values specified in families from the given range.
func (c *Client) Scan(s *hrpc.Scan) ([]*hrpc.Result, error) {
var results []*pb.Result
var scanres *pb.ScanResponse
var rpc *hrpc.Scan
ctx := s.GetContext()
table := s.Table()
families := s.GetFamilies()
filters := s.GetFilter()
startRow := s.GetStartRow()
stopRow := s.GetStopRow()
for {
// Make a new Scan RPC for this region
if rpc != nil {
// If it's not the first region, we want to start at whatever the
// last region's StopKey was
startRow = rpc.GetRegionStop()
}
rpc, err := hrpc.NewScanRange(ctx, table, startRow, stopRow,
hrpc.Families(families), hrpc.Filters(filters))
if err != nil {
return nil, err
}
res, err := c.sendRPC(rpc)
if err != nil {
return nil, err
}
scanres = res.(*pb.ScanResponse)
results = append(results, scanres.Results...)
// TODO: The more_results field of the ScanResponse object was always
// true, so we should figure out if there's a better way to know when
// to move on to the next region than making an extra request and
// seeing if there were no results
for len(scanres.Results) != 0 {
rpc = hrpc.NewScanFromID(ctx, table, *scanres.ScannerId, rpc.Key())
res, err = c.sendRPC(rpc)
if err != nil {
return nil, err
}
scanres = res.(*pb.ScanResponse)
results = append(results, scanres.Results...)
}
rpc = hrpc.NewCloseFromID(ctx, table, *scanres.ScannerId, rpc.Key())
if err != nil {
return nil, err
}
res, err = c.sendRPC(rpc)
// Check to see if this region is the last we should scan (either
// because (1) it's the last region or (3) because its stop_key is
// greater than or equal to the stop_key of this scanner provided
// that (2) we're not trying to scan until the end of the table).
// (1)
if len(rpc.GetRegionStop()) == 0 ||
// (2) (3)
len(stopRow) != 0 && bytes.Compare(stopRow, rpc.GetRegionStop()) <= 0 {
// Do we want to be returning a slice of Result objects or should we just
// put all the Cells into the same Result object?
localResults := make([]*hrpc.Result, len(results))
for idx, result := range results {
localResults[idx] = hrpc.ToLocalResult(result)
}
return localResults, nil
}
}
}
func confirmScanAttributes(s *hrpc.Scan, ctx context.Context, table, start, stop []byte,
fam map[string][]string, filter1 filter.Filter) bool {
if s.Context() != ctx ||
!bytes.Equal(s.Table(), table) ||
!bytes.Equal(s.StartRow(), start) ||
!bytes.Equal(s.StopRow(), stop) ||
!reflect.DeepEqual(s.Families(), fam) ||
reflect.TypeOf(s.Filter()) != reflect.TypeOf(filter1) {
return false
}
return true
}