func (a *Airspace) thisIsNewContent(msg *adsb.CompositeMsg) (wasNew bool) {
// Lazy init
if a.RollAfter == time.Minute*0 {
a.RollAfter = DefaultRollAfter
}
if a.Aircraft == nil {
a.Aircraft = make(map[adsb.IcaoId]AircraftData)
}
sig := msg.GetSignature()
if _, existsCurr := a.CurrMsgs[sig]; !existsCurr {
// Add it into Curr in all cases
a.CurrMsgs[sig] = true
existsPrev := false
if a.PrevMsgs != nil {
_, existsPrev = a.PrevMsgs[sig]
}
// If the thing was already in prev, then it isn't new; else it is
return !existsPrev
}
return false
}
// If this message has new position info, *and* we have good backfill, then craft a CompositeMsg.
// Note, we don't wait for squawk info.
func (s *ADSBSender) maybeCreateComposite(m *adsb.Msg) *adsb.CompositeMsg {
if !m.HasPosition() {
return nil
}
//if s.LastGroundSpeed == 0 || s.LastTrack == 0 || s.LastCallsign == "" { return nil }
cm := adsb.CompositeMsg{Msg: *m} // Clone the input into the embedded struct
// Overwrite with cached info (from previous packets), if we don't have it in this packet
if cm.GroundSpeed == 0 {
cm.GroundSpeed = s.LastGroundSpeed
}
if cm.VerticalRate == 0 {
cm.VerticalRate = s.LastVerticalSpeed
}
if cm.Track == 0 {
cm.Track = s.LastTrack
}
if cm.Callsign == "" {
cm.Callsign = s.LastCallsign
}
if cm.Squawk == "" {
cm.Squawk = s.LastSquawk
}
return &cm
}
