[core] Add templated RTTI for RenderSource classes

7 files changed, 44 insertions, 4 deletions

diff --git a/src/mbgl/annotation/render_annotation_source.hpp b/src/mbgl/annotation/render_annotation_source.hpp
index 539e73b57e..980d9d27e9 100644
--- a/src/mbgl/annotation/render_annotation_source.hpp
+++ b/src/mbgl/annotation/render_annotation_source.hpp
@@ -52,4 +52,9 @@ private:
     TilePyramid tilePyramid;
 };
 
+template <>
+inline bool RenderSource::is<RenderAnnotationSource>() const {
+    return baseImpl->type == SourceType::Annotations;
+}
+
 } // namespace mbgl
diff --git a/src/mbgl/renderer/layers/render_raster_layer.cpp b/src/mbgl/renderer/layers/render_raster_layer.cpp
index 49983462a3..28cf722c14 100644
--- a/src/mbgl/renderer/layers/render_raster_layer.cpp
+++ b/src/mbgl/renderer/layers/render_raster_layer.cpp
@@ -38,8 +38,8 @@ bool RenderRasterLayer::hasTransition() const {
 
 void RenderRasterLayer::uploadBuckets(gl::Context& context, RenderSource* source) {
     RenderLayer::uploadBuckets(context, source);
-    if (renderTiles.size() == 0) {
-        RenderImageSource* imageSource = dynamic_cast<RenderImageSource*>(source);
+    if (renderTiles.empty()) {
+        RenderImageSource* imageSource = source->as<RenderImageSource>();
         if (imageSource) {
             imageSource->upload(context);
         }
@@ -48,8 +48,8 @@ void RenderRasterLayer::uploadBuckets(gl::Context& context, RenderSource* source
 
 void RenderRasterLayer::render(Painter& painter, PaintParameters& parameters, RenderSource* source) {
     RenderLayer::render(painter, parameters, source);
-    if (renderTiles.size() == 0) {
-        RenderImageSource* imageSource = dynamic_cast<RenderImageSource*>(source);
+    if (renderTiles.empty()) {
+        RenderImageSource* imageSource = source->as<RenderImageSource>();
         if (imageSource) {
             imageSource->render(painter, parameters, *this);
         }
diff --git a/src/mbgl/renderer/render_source.hpp b/src/mbgl/renderer/render_source.hpp
index 994d600613..dae0ea19b1 100644
--- a/src/mbgl/renderer/render_source.hpp
+++ b/src/mbgl/renderer/render_source.hpp
@@ -33,6 +33,21 @@ public:
 
     ~RenderSource() override = default;
 
+    // Check whether this source is of the given subtype.
+    template <class T>
+    bool is() const;
+
+    // Dynamically cast this source to the given subtype.
+    template <class T>
+    T* as() {
+        return is<T>() ? reinterpret_cast<T*>(this) : nullptr;
+    }
+
+    template <class T>
+    const T* as() const {
+        return is<T>() ? reinterpret_cast<const T*>(this) : nullptr;
+    }
+
     virtual bool isLoaded() const = 0;
 
     // Called when the camera has changed. May load new tiles, unload obsolete tiles, or
diff --git a/src/mbgl/renderer/sources/render_geojson_source.hpp b/src/mbgl/renderer/sources/render_geojson_source.hpp
index 0f9379b9b6..51caf43714 100644
--- a/src/mbgl/renderer/sources/render_geojson_source.hpp
+++ b/src/mbgl/renderer/sources/render_geojson_source.hpp
@@ -57,4 +57,9 @@ private:
     style::GeoJSONData* data;
 };
 
+template <>
+inline bool RenderSource::is<RenderGeoJSONSource>() const {
+    return baseImpl->type == SourceType::GeoJSON;
+}
+
 } // namespace mbgl
diff --git a/src/mbgl/renderer/sources/render_image_source.hpp b/src/mbgl/renderer/sources/render_image_source.hpp
index 86c17b10fd..54afca4bee 100644
--- a/src/mbgl/renderer/sources/render_image_source.hpp
+++ b/src/mbgl/renderer/sources/render_image_source.hpp
@@ -65,4 +65,9 @@ private:
     bool shouldRender;
 };
 
+template <>
+inline bool RenderSource::is<RenderImageSource>() const {
+    return baseImpl->type == SourceType::Image;
+}
+
 } // namespace mbgl
diff --git a/src/mbgl/renderer/sources/render_raster_source.hpp b/src/mbgl/renderer/sources/render_raster_source.hpp
index 9bf4436bc7..d0714aee06 100644
--- a/src/mbgl/renderer/sources/render_raster_source.hpp
+++ b/src/mbgl/renderer/sources/render_raster_source.hpp
@@ -53,4 +53,9 @@ private:
     optional<std::vector<std::string>> tileURLTemplates;
 };
 
+template <>
+inline bool RenderSource::is<RenderRasterSource>() const {
+    return baseImpl->type == SourceType::Raster;
+}
+
 } // namespace mbgl
diff --git a/src/mbgl/renderer/sources/render_vector_source.hpp b/src/mbgl/renderer/sources/render_vector_source.hpp
index b3704a1274..f3de27d78a 100644
--- a/src/mbgl/renderer/sources/render_vector_source.hpp
+++ b/src/mbgl/renderer/sources/render_vector_source.hpp
@@ -53,4 +53,9 @@ private:
     optional<std::vector<std::string>> tileURLTemplates;
 };
 
+template <>
+inline bool RenderSource::is<RenderVectorSource>() const {
+    return baseImpl->type == SourceType::Vector;
+}
+
 } // namespace mbgl