Keep sources in memory

[tobrun]

When looking into mapbox/mapbox-gl-native#11843. I'm noticing the following in MapUtils:

  public static void updateMapSourceFromFeatureCollection(@NonNull MapboxMap mapboxMap,
                                                          @Nullable FeatureCollection collection,
                                                          @NonNull String sourceId) {
    if (collection == null) {
      collection = FeatureCollection.fromFeatures(new Feature[] {});
    }

    GeoJsonSource source = mapboxMap.getSourceAs(sourceId);
    if (source == null) {
      GeoJsonOptions routeGeoJsonOptions = new GeoJsonOptions().withMaxZoom(16);
      GeoJsonSource routeSource = new GeoJsonSource(sourceId, collection, routeGeoJsonOptions);
      mapboxMap.addSource(routeSource);
    } else {
      source.setGeoJson(collection);
    }
  }

With every update we are getting the source from MapboxMap, this is an expensive task which requires to go through JNI to C++ an back. Instead of creating new instances with getSourceAs we should cache the value of the source.

[danesfeder]

@Guardiola31337 maybe this can be part of refactoring NavigationMapRoute? The better approach @tobrun is explaining here is the same as the new LLP code that I was showing you.

[tobrun]

The idea here is to keep sources/layers in memory and reload them when a new style has been loaded (map change event).

[rishabhsri20]

Any solution for this freeze? Happens with me when starting a navigation.

[danesfeder]

Hey @rishabhsri20, this ticket is "next up" for our pipeline of work - stay tuned for updates as we update this ticket once work begins. Thank you for your patience!

[danesfeder]

@LukasPaczos I recall having a brief discussion about this during #1387 - we would get some performance wins by not using the MapUtil as Tobrun mentioned?

[tobrun]

@danesfeder since v7.0.0 this is optimised under the hood, if you can Style#getSource(id) it will return a cached source if available (same goes for layers).

  @Nullable
  public Source getSource(String id) {
    validateState("getSource");
    Source source = sources.get(id);
    if (source == null) {
      source = nativeMapView.getSource(id);
    }
    return source;
  }

Don't think this issue is actionable anymore.

[danesfeder]

Awesome thanks for the clarification here @tobrun, closing with #1615