partial subscriptions

not really partial. they just happen per peripheral now

providers/iracing/iracing.go

@@ -29,13 +29,14 @@ type IRacing struct {
 	mut      sync.Mutex
 	data     *telemetry.TelemetryData
 	updaters [telemetry.MaxFields]func(*telemetry.TelemetryField)
+	// Field Subscription management
+	boundFields map[telemetry.FieldID]bool
 
 	// Timing information
 	ticker *time.Ticker // ticker will keep polling intervals constant
 
 	// Stream
-	wg sync.WaitGroup
-	// streamCh     chan telemetry.TelemetryData
+	wg           sync.WaitGroup
 	streamCancel context.CancelFunc
 }
 
@@ -55,6 +56,8 @@ func NewIRacingProvider(
 		logger: logger,
 		SDK:    sdk,
 		data:   telemetry.NewTelemetryData(),
+		// Field subscription management
+		boundFields: make(map[telemetry.FieldID]bool, telemetry.MaxFields),
 		// TODO: make this configurable from the user side
 		ticker: time.NewTicker(time.Second / 60),
 	}
@@ -225,46 +228,67 @@ func (i *IRacing) StopStream() {
 	i.streamCancel = nil
 }
 
-func (i *IRacing) Subscribe(requestFields []telemetry.FieldID) {
-	i.logger.Debug(fmt.Sprintf("Len Req: %d\n", len(requestFields)))
+// TODO: this function is exactly the same in BeamNG drive now, and I reckon it will be the same
+// In plenty other things. I should make it TelemetryData method
+func (i *IRacing) subscribe(fields []telemetry.FieldID) []string {
+	newSubscriptions := make([]string, 0, telemetry.MaxFields)
 
-	i.data.ActiveBinds = make([]telemetry.BoundField, 0, len(requestFields))
+	i.mut.Lock()
+	defer i.mut.Unlock()
 
-	// First we must add the virtual fields
-	// we will add their dependencies and the primitives to a slice
-	pendingBinds := make([]telemetry.FieldID, 0, telemetry.MaxFields)
-
-	for _, id := range requestFields {
-		switch id {
-		case telemetry.RPMStateColour:
-			i.data.VirtualBinds = append(i.data.VirtualBinds, telemetry.NewRPMLights())
-		case telemetry.FCCurrentLap:
-			i.data.VirtualBinds = append(i.data.VirtualBinds,
-				telemetry.NewFuelCalculator(i.logger.WithGroup("FUEL CALC")))
-		default:
-			// primitive telemetry field
-			pendingBinds = append(pendingBinds, id)
-		}
-	}
-
-	boundCheck := make(map[telemetry.FieldID]bool)
-
-	// Now that we know all the fields we need to bind we follow the binding procedure
-	for _, id := range pendingBinds {
-		// Check if we already bound this FieldID
-		if boundCheck[id] {
+	for _, id := range fields {
+		if i.boundFields[id] {
 			continue
 		}
 
-		binding := telemetry.BoundField{
+		i.data.ActiveBinds[id] = telemetry.BoundField{
 			ID: id,
 		}
-
-		i.data.ActiveBinds = append(i.data.ActiveBinds, binding)
-		boundCheck[id] = true
+		i.boundFields[id] = true
+		newSubscriptions = append(newSubscriptions, telemetry.FieldNames[id])
 	}
 
+	// unsubscribe from fields we many not need anymore
+	for key, bound := range i.boundFields {
+		if _, ok := i.data.ActiveBinds[key]; bound && !ok {
+			delete(i.data.ActiveBinds, key)
+			i.boundFields[key] = false
+		}
+	}
+
+	return newSubscriptions
+}
+
+func (i *IRacing) Subscribe(requestFields []telemetry.FieldID) []string {
+	i.logger.Debug(fmt.Sprintf("Len Req: %d\n", len(requestFields)))
+
+	// First we must add the virtual fields
+	// we will add their dependencies and the primitives to a slice
+	toBind := make([]telemetry.FieldID, 0, telemetry.MaxFields)
+
+	i.mut.Lock()
+	for _, id := range requestFields {
+		switch id {
+		case telemetry.RPMStateColour:
+			rpmLights := telemetry.NewRPMLights()
+			i.data.VirtualBinds[rpmLights.Name()] = rpmLights
+			toBind = append(toBind, rpmLights.EnsureSubscribed()...)
+		case telemetry.FCCurrentLap:
+			fuelCalc := telemetry.NewFuelCalculator(i.logger.WithGroup("FUEL CALC"))
+			i.data.VirtualBinds[fuelCalc.Name()] = fuelCalc
+			toBind = append(toBind, fuelCalc.EnsureSubscribed()...)
+		default:
+			// primitive telemetry field
+			toBind = append(toBind, id)
+		}
+	}
+	i.mut.Unlock()
+
+	newSubs := i.subscribe(toBind)
+
 	i.logger.Debug(fmt.Sprintf("Subscribed: %+v\n", i.data.ActiveBinds))
+
+	return newSubs
 }
 
 func (i *IRacing) Name() string {