influxdb/storage/reads/string_iterator_writer.go

76 lines
1.3 KiB
Go

package reads
import (
"github.com/influxdata/influxdb/storage/reads/datatypes"
"github.com/influxdata/influxdb/tsdb/cursors"
)
type StringIteratorStream interface {
Send(*datatypes.StringValuesResponse) error
}
type StringIteratorWriter struct {
stream StringIteratorStream
res *datatypes.StringValuesResponse
err error
sz int // estimated size in bytes for pending write
vc int // total value count
}
func NewStringIteratorWriter(stream StringIteratorStream) *StringIteratorWriter {
siw := &StringIteratorWriter{
stream: stream,
res: &datatypes.StringValuesResponse{
Values: nil,
},
}
return siw
}
func (w *StringIteratorWriter) Err() error {
return w.err
}
func (w *StringIteratorWriter) WrittenN() int {
return w.vc
}
func (w *StringIteratorWriter) WriteStringIterator(si cursors.StringIterator) error {
if si == nil {
return nil
}
for si.Next() {
v := si.Value()
if v == "" {
// no value, no biggie
continue
}
w.res.Values = append(w.res.Values, []byte(v))
w.sz += len(v)
w.vc++
}
return nil
}
func (w *StringIteratorWriter) Flush() {
if w.err != nil || w.sz == 0 {
return
}
w.sz, w.vc = 0, 0
if w.err = w.stream.Send(w.res); w.err != nil {
return
}
for i := range w.res.Values {
w.res.Values[i] = nil
}
w.res.Values = w.res.Values[:0]
}