Move simulate route line progress calculation to bg thread (#3442)

GitOrigin-RevId: 67087f5be23ff97589c9737e5af287fdddf8af0a

Author: jush

app/src/main/java/com/mapbox/maps/testapp/utils/SimulateRouteLocationProvider.kt

@@ -1,28 +1,38 @@
 package com.mapbox.maps.testapp.utils
 
-import android.os.Handler
-import android.os.Looper
 import com.mapbox.geojson.LineString
 import com.mapbox.geojson.Point
 import com.mapbox.maps.plugin.locationcomponent.LocationConsumer
 import com.mapbox.maps.plugin.locationcomponent.LocationProvider
 import com.mapbox.turf.TurfConstants
 import com.mapbox.turf.TurfMeasurement
 import com.mapbox.turf.TurfMisc
-import java.util.concurrent.*
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancelAndJoin
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.util.concurrent.CopyOnWriteArraySet
 
 /**
  * A location provider implementation that takes in a line string as route and animate the location
  * updates along the route.
  */
 class SimulateRouteLocationProvider(
   val route: LineString,
-  private val handler: Handler = Handler(Looper.getMainLooper())
 ) : LocationProvider {
-  private val totalRouteLength = TurfMeasurement.length(route, TurfConstants.UNIT_CENTIMETERS)
+  private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
+  private var emitLocationsJob: Job? = null
+  private val totalRouteLength by lazy { TurfMeasurement.length(route, TurfConstants.UNIT_CENTIMETERS) }
   private val routeStartPoint = route.coordinates().first()
   private val locationConsumers = CopyOnWriteArraySet<LocationConsumer>()
   private var isFakeLocationEmitting = false
+  private val iterator = route.coordinates().toMutableList().iterator()
+
   override fun registerLocationConsumer(locationConsumer: LocationConsumer) {
     locationConsumers.add(locationConsumer)
     if (!isFakeLocationEmitting) {
@@ -34,35 +44,34 @@ class SimulateRouteLocationProvider(
   override fun unRegisterLocationConsumer(locationConsumer: LocationConsumer) {
     locationConsumers.remove(locationConsumer)
     if (locationConsumers.isEmpty()) {
+      emitLocationsJob?.cancel()
       isFakeLocationEmitting = false
     }
   }
 
-  private val pointList = route.coordinates().toMutableList()
-  private val iterator = pointList.iterator()
-  private var lastLocation: Point =
-    if (iterator.hasNext()) iterator.next() else Point.fromLngLat(0.0, 0.0)
-  private var lastBearing = 0.0
-
   private fun emitFakeLocations() {
-    handler.postDelayed(
-      {
-        if (iterator.hasNext()) {
-          val point = iterator.next().insertProgressInfo()
-          val bearing = TurfMeasurement.bearing(lastLocation, point)
-          lastLocation = point
-          lastBearing = bearing
-          iterator.remove()
+    val previousEmitLocationsJob = emitLocationsJob
+    emitLocationsJob = scope.launch {
+      // Make sure previous job is cancelled before starting a new one
+      previousEmitLocationsJob?.cancelAndJoin()
+      var lastLocation: Point = if (iterator.hasNext()) {
+        iterator.next()
+      } else {
+        Point.fromLngLat(0.0, 0.0)
+      }
+      while (isActive && iterator.hasNext()) {
+        val point = iterator.next().insertProgressInfo()
+        val bearing = TurfMeasurement.bearing(lastLocation, point)
+        lastLocation = point
+        iterator.remove()
 
+        withContext(Dispatchers.Main) {
           locationConsumers.forEach { it.onLocationUpdated(point) }
           locationConsumers.forEach { it.onBearingUpdated(bearing) }
         }
-        if (iterator.hasNext() && isFakeLocationEmitting) {
-          emitFakeLocations()
-        }
-      },
-      LOCATION_UPDATE_INTERVAL_MS
-    )
+        delay(LOCATION_UPDATE_INTERVAL_MS)
+      }
+    }
   }
 
   // use altitude of Point to pass through progress data, and use internal animator to interpolate

compose-app/src/main/java/com/mapbox/maps/compose/testapp/examples/utils/SimulateRouteLocationProvider.kt

@@ -1,14 +1,21 @@
 package com.mapbox.maps.compose.testapp.examples.utils
 
-import android.os.Handler
-import android.os.Looper
 import com.mapbox.geojson.LineString
 import com.mapbox.geojson.Point
 import com.mapbox.maps.plugin.locationcomponent.LocationConsumer
 import com.mapbox.maps.plugin.locationcomponent.LocationProvider
 import com.mapbox.turf.TurfConstants
 import com.mapbox.turf.TurfMeasurement
 import com.mapbox.turf.TurfMisc
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancelAndJoin
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import java.util.concurrent.CopyOnWriteArraySet
 
 /**
@@ -17,12 +24,14 @@ import java.util.concurrent.CopyOnWriteArraySet
  */
 public class SimulateRouteLocationProvider(
   private val route: LineString,
-  private val handler: Handler = Handler(Looper.getMainLooper())
 ) : LocationProvider {
-  private val totalRouteLength = TurfMeasurement.length(route, TurfConstants.UNIT_CENTIMETERS)
+  private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
+  private var emitLocationsJob: Job? = null
+  private val totalRouteLength by lazy { TurfMeasurement.length(route, TurfConstants.UNIT_CENTIMETERS) }
   private val routeStartPoint = route.coordinates().first()
   private val locationConsumers = CopyOnWriteArraySet<LocationConsumer>()
   private var isFakeLocationEmitting = false
+  private val iterator = route.coordinates().toMutableList().iterator()
 
   override fun registerLocationConsumer(locationConsumer: LocationConsumer) {
     locationConsumers.add(locationConsumer)
@@ -35,35 +44,34 @@ public class SimulateRouteLocationProvider(
   override fun unRegisterLocationConsumer(locationConsumer: LocationConsumer) {
     locationConsumers.remove(locationConsumer)
     if (locationConsumers.isEmpty()) {
+      emitLocationsJob?.cancel()
       isFakeLocationEmitting = false
     }
   }
 
-  private val pointList = route.coordinates().toMutableList()
-  private val iterator = pointList.iterator()
-  private var lastLocation: Point =
-    if (iterator.hasNext()) iterator.next() else Point.fromLngLat(0.0, 0.0)
-  private var lastBearing = 0.0
-
   private fun emitFakeLocations() {
-    handler.postDelayed(
-      {
-        if (iterator.hasNext()) {
-          val point = iterator.next().insertProgressInfo()
-          val bearing = TurfMeasurement.bearing(lastLocation, point)
-          lastLocation = point
-          lastBearing = bearing
-          iterator.remove()
+    val previousEmitLocationsJob = emitLocationsJob
+    emitLocationsJob = scope.launch {
+      // Make sure previous job is cancelled before starting a new one
+      previousEmitLocationsJob?.cancelAndJoin()
+      var lastLocation: Point = if (iterator.hasNext()) {
+        iterator.next()
+      } else {
+        Point.fromLngLat(0.0, 0.0)
+      }
+      while (isActive && iterator.hasNext()) {
+        val point = iterator.next().insertProgressInfo()
+        val bearing = TurfMeasurement.bearing(lastLocation, point)
+        lastLocation = point
+        iterator.remove()
 
+        withContext(Dispatchers.Main) {
           locationConsumers.forEach { it.onLocationUpdated(point) }
           locationConsumers.forEach { it.onBearingUpdated(bearing) }
         }
-        if (iterator.hasNext() && isFakeLocationEmitting) {
-          emitFakeLocations()
-        }
-      },
-      LOCATION_UPDATE_INTERVAL_MS
-    )
+        delay(LOCATION_UPDATE_INTERVAL_MS)
+      }
+    }
   }
 
   // use altitude of Point to pass through progress data, and use internal animator to interpolate