82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
package query
|
|
|
|
import (
|
|
"github.com/influxdata/influxdb/v2/models"
|
|
)
|
|
|
|
// Emitter reads from a cursor into rows.
|
|
type Emitter struct {
|
|
cur Cursor
|
|
chunkSize int
|
|
|
|
series Series
|
|
row *models.Row
|
|
columns []string
|
|
}
|
|
|
|
// NewEmitter returns a new instance of Emitter that pulls from itrs.
|
|
func NewEmitter(cur Cursor, chunkSize int) *Emitter {
|
|
columns := make([]string, len(cur.Columns()))
|
|
for i, col := range cur.Columns() {
|
|
columns[i] = col.Val
|
|
}
|
|
return &Emitter{
|
|
cur: cur,
|
|
chunkSize: chunkSize,
|
|
columns: columns,
|
|
}
|
|
}
|
|
|
|
// Close closes the underlying iterators.
|
|
func (e *Emitter) Close() error {
|
|
return e.cur.Close()
|
|
}
|
|
|
|
// Emit returns the next row from the iterators.
|
|
func (e *Emitter) Emit() (*models.Row, bool, error) {
|
|
// Continually read from the cursor until it is exhausted.
|
|
for {
|
|
// Scan the next row. If there are no rows left, return the current row.
|
|
var row Row
|
|
if !e.cur.Scan(&row) {
|
|
if err := e.cur.Err(); err != nil {
|
|
return nil, false, err
|
|
}
|
|
r := e.row
|
|
e.row = nil
|
|
return r, false, nil
|
|
}
|
|
|
|
// If there's no row yet then create one.
|
|
// If the name and tags match the existing row, append to that row if
|
|
// the number of values doesn't exceed the chunk size.
|
|
// Otherwise return existing row and add values to next emitted row.
|
|
if e.row == nil {
|
|
e.createRow(row.Series, row.Values)
|
|
} else if e.series.SameSeries(row.Series) {
|
|
if e.chunkSize > 0 && len(e.row.Values) >= e.chunkSize {
|
|
r := e.row
|
|
r.Partial = true
|
|
e.createRow(row.Series, row.Values)
|
|
return r, true, nil
|
|
}
|
|
e.row.Values = append(e.row.Values, row.Values)
|
|
} else {
|
|
r := e.row
|
|
e.createRow(row.Series, row.Values)
|
|
return r, true, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
// createRow creates a new row attached to the emitter.
|
|
func (e *Emitter) createRow(series Series, values []interface{}) {
|
|
e.series = series
|
|
e.row = &models.Row{
|
|
Name: series.Name,
|
|
Tags: series.Tags.KeyValues(),
|
|
Columns: e.columns,
|
|
Values: [][]interface{}{values},
|
|
}
|
|
}
|