[core] Added RendererState::has{Image,Layer,Source}

include/mbgl/renderer/renderer_state.hpp

@@ -8,7 +8,7 @@ namespace mbgl {
 class UpdateParameters;
 
 /**
- * RendererState acts as a Memento-like object that is able to extract data out of UpdateParameters (an opaque object
+ * RendererState acts as a Memento object that is able to extract data out of UpdateParameters (an opaque object
  * from the public API perspective).
  */
 class RendererState {
@@ -17,6 +17,14 @@ public:
     // Obtains a CameraOptions out of a given UpdateParameters object.
     static CameraOptions getCameraOptions(UpdateParameters&, const EdgeInsets& = {});
 
+    // Returns whether an image with the given ID exists from a given UpdateParamters object.
+    static bool hasImage(UpdateParameters&, const std::string& id);
+
+    // Returns whether a layer with the given ID exists from a given UpdateParamters object.
+    static bool hasLayer(UpdateParameters&, const std::string& id);
+
+    // Returns whether a source with the given ID exists from a given UpdateParamters object.
+    static bool hasSource(UpdateParameters&, const std::string& id);
 };
 
 } // namespace mbgl

platform/default/mbgl/gl/headless_frontend.cpp

@@ -64,6 +64,30 @@ CameraOptions HeadlessFrontend::getCameraOptions() {
     return nullCamera;
 }
 
+bool HeadlessFrontend::hasImage(const std::string& id) {
+    if (updateParameters) {
+        return RendererState::hasImage(*updateParameters, id);
+    }
+
+    return false;
+}
+
+bool HeadlessFrontend::hasLayer(const std::string& id) {
+    if (updateParameters) {
+        return RendererState::hasLayer(*updateParameters, id);
+    }
+
+    return false;
+}
+
+bool HeadlessFrontend::hasSource(const std::string& id) {
+    if (updateParameters) {
+        return RendererState::hasSource(*updateParameters, id);
+    }
+
+    return false;
+}
+
 void HeadlessFrontend::setSize(Size size_) {
     if (size != size_) {
         size = size_;

platform/default/mbgl/gl/headless_frontend.hpp

@@ -35,6 +35,10 @@ public:
     RendererBackend* getBackend();
     CameraOptions getCameraOptions();
 
+    bool hasImage(const std::string&);
+    bool hasLayer(const std::string&);
+    bool hasSource(const std::string&);
+
     PremultipliedImage readStillImage();
     PremultipliedImage render(Map&);
 

src/mbgl/renderer/renderer_state.cpp

@@ -1,10 +1,42 @@
 #include <mbgl/renderer/renderer_state.hpp>
 #include <mbgl/renderer/update_parameters.hpp>
 
+#include <mbgl/style/image_impl.hpp>
+#include <mbgl/style/layer_impl.hpp>
+#include <mbgl/style/source_impl.hpp>
+
 namespace mbgl {
 
 CameraOptions RendererState::getCameraOptions(UpdateParameters& updateParameters, const EdgeInsets& padding) {
     return updateParameters.transformState.getCameraOptions(padding);
 }
 
+bool RendererState::hasImage(UpdateParameters& updateParameters, const std::string& id) {
+    for (const auto& image : *updateParameters.images) {
+        if (image.get()->id == id) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool RendererState::hasLayer(UpdateParameters& updateParameters, const std::string& id) {
+    for (const auto& layer : *updateParameters.layers) {
+        if (layer.get()->id == id) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool RendererState::hasSource(UpdateParameters& updateParameters, const std::string& id) {
+    for (const auto& source : *updateParameters.sources) {
+        if (source.get()->id == id) {
+            return true;
+        }
+    }
+    return false;
+}
+
+
 } // namespace mbgl

test/map/map.test.cpp

@@ -18,6 +18,8 @@
 #include <mbgl/style/style.hpp>
 #include <mbgl/style/image.hpp>
 #include <mbgl/style/layers/background_layer.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
+#include <mbgl/style/sources/geojson_source.hpp>
 #include <mbgl/util/color.hpp>
 
 using namespace mbgl;
@@ -69,12 +71,48 @@ TEST(Map, RendererState) {
     test.runLoop.runOnce();
     test.frontend.render(test.map);
 
+    // RendererState::getCameraOptions
     const CameraOptions& options = test.frontend.getCameraOptions();
     EXPECT_NEAR(options.center->latitude(), coordinate.latitude(), 1e-7);
     EXPECT_NEAR(options.center->longitude(), coordinate.longitude(), 1e-7);
     ASSERT_DOUBLE_EQ(*options.zoom, zoom);
     ASSERT_DOUBLE_EQ(*options.pitch, pitchInDegrees);
     EXPECT_NEAR(*options.angle, bearingInDegrees, 1e-7);
+
+    // RendererState::hasImage
+    test.map.getStyle().addImage(std::make_unique<style::Image>("default_marker", decodeImage(util::read_file("test/fixtures/sprites/default_marker.png")), 1.0));
+
+    // The frontend has not yet been notified about the newly-added image.
+    EXPECT_FALSE(test.frontend.hasImage("default_marker"));
+
+    test.runLoop.runOnce();
+    test.frontend.render(test.map);
+
+    EXPECT_TRUE(test.frontend.hasImage("default_marker"));
+
+    // RendererState::hasSource
+    auto source = std::make_unique<GeoJSONSource>("GeoJSONSource");
+    source->setGeoJSON( Geometry<double>{ Point<double>{ 0, 0 } } );
+    test.map.getStyle().addSource(std::move(source));
+
+    // The frontend has not yet been notified about the newly-added source.
+    EXPECT_FALSE(test.frontend.hasSource("GeoJSONSource"));
+
+    test.runLoop.runOnce();
+    test.frontend.render(test.map);
+
+    EXPECT_TRUE(test.frontend.hasSource("GeoJSONSource"));
+
+    // RendererState::hasLayer
+    test.map.getStyle().addLayer(std::make_unique<SymbolLayer>("SymbolLayer", "GeoJSONSource"));
+
+    // The frontend has not yet been notified about the newly-added source.
+    EXPECT_FALSE(test.frontend.hasLayer("SymbolLayer"));
+
+    test.runLoop.runOnce();
+    test.frontend.render(test.map);
+
+    EXPECT_TRUE(test.frontend.hasLayer("SymbolLayer"));
 }
 
 TEST(Map, LatLngBehavior) {