// fillArchive() is a private function that fills data points from srcWSP
// into dstWsp. Used by FIll()
// * srcWsp and dstWsp are *whisper.Whisper open files
// * start and stop define an inclusive time window to fill
// On error an error value is returned.
//
// This code heavily inspired by https://github.com/jssjr/carbonate
func fillArchive(srcWsp, dstWsp *whisper.Whisper, start, stop int) error {
// Fetch the range defined by start and stop always taking the values
// from the highest precision archive, which man require multiple
// fetch/merge updates.
srcRetentions := whisper.RetentionsByPrecision{srcWsp.Retentions()}
sort.Sort(srcRetentions)
if start < srcWsp.StartTime() && stop < srcWsp.StartTime() {
// Nothing to fill/merge
return nil
}
// Begin our backwards walk in time
for _, v := range srcRetentions.Iterator() {
points := make([]*whisper.TimeSeriesPoint, 0)
rTime := int(time.Now().Unix()) - v.MaxRetention()
if stop <= rTime {
// This archive contains no data points in the window
continue
}
// Start and the start time or the beginning of this archive
fromTime := start
if rTime > start {
fromTime = rTime
}
ts, err := srcWsp.Fetch(fromTime, stop)
if err != nil {
return err
}
// Build a list of points to merge
tsStart := ts.FromTime()
for _, dp := range ts.Values() {
if !math.IsNaN(dp) {
points = append(points, &whisper.TimeSeriesPoint{tsStart, dp})
}
tsStart += ts.Step()
}
dstWsp.UpdateMany(points)
stop = fromTime
if start >= stop {
// Nothing more to fetch
break
}
}
return nil
}
