[core][Android][Darwin] LayerManager creates RenderLayer instances

`LayerManager` is now responsible for `RenderLayer` instances creation,
so that there is a single entry point for creating of objects, which
correspond to a certain layer type.

The `LayerType type` field is dropped from `Layer::Impl`.

12 files changed, 84 insertions, 98 deletions

diff --git a/include/mbgl/style/layer.hpp b/include/mbgl/style/layer.hpp
index 5c1b361419..9e73e994e6 100644
--- a/include/mbgl/style/layer.hpp
+++ b/include/mbgl/style/layer.hpp
@@ -74,8 +74,7 @@ public:
     Layer& operator=(const Layer&) = delete;
 
     virtual ~Layer();
-    // Note: LayerType is deprecated, do not use it.
-    LayerType getType() const;
+
     std::string getID() const;
     // Source
     std::string getSourceID() const;
@@ -126,6 +125,10 @@ protected:
     LayerObserver* observer;
 };
 
+} // namespace style
+
+class RenderLayer;
+// TODO: The following classes shall not be here. Move layer factories and manager to a dedicated folder.
 
 /**
  * @brief The LayerFactory abstract class
@@ -136,17 +139,19 @@ class LayerFactory {
 public:
     virtual ~LayerFactory() = default;
     /// Returns the layer type data.
-    virtual const LayerTypeInfo* getTypeInfo() const noexcept = 0;
+    virtual const style::LayerTypeInfo* getTypeInfo() const noexcept = 0;
     /// Returns a new Layer instance on success call; returns `nulltptr` otherwise. 
-    virtual std::unique_ptr<Layer> createLayer(const std::string& id, const conversion::Convertible& value) = 0;
+    virtual std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept = 0;
+    /// Returns a new RenderLayer instance on success call; returns `nulltptr` otherwise.
+    virtual std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept = 0;
 
 protected:
-    optional<std::string> getSource(const conversion::Convertible& value) const noexcept;
-    bool initSourceLayerAndFilter(Layer*, const conversion::Convertible& value) const noexcept;
+    optional<std::string> getSource(const style::conversion::Convertible& value) const noexcept;
+    bool initSourceLayerAndFilter(style::Layer*, const style::conversion::Convertible& value) const noexcept;
 };
 
 /**
- * @brief A singleton class forwarding calls to the corresponding  \c LayerFactory instance.
+ * @brief A singleton class responsible for creating layer instances.
  */
 class LayerManager {
 public:
@@ -157,13 +162,16 @@ public:
      */
     static LayerManager* get() noexcept;
 
-    virtual ~LayerManager() = default;
     /// Returns a new Layer instance on success call; returns `nulltptr` otherwise.
-    virtual std::unique_ptr<Layer> createLayer(const std::string& type, const std::string& id, const conversion::Convertible& value, conversion::Error& error) noexcept = 0;
+    std::unique_ptr<style::Layer> createLayer(const std::string& type, const std::string& id,
+                                              const style::conversion::Convertible& value, style::conversion::Error& error) noexcept;
+    /// Returns a new RenderLayer instance on success call; returns `nulltptr` otherwise.
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept;
 
 protected:
-    LayerManager() = default;
+    virtual ~LayerManager() = default;
+    virtual LayerFactory* getFactory(const std::string& type) noexcept = 0;
+    virtual LayerFactory* getFactory(const style::LayerTypeInfo*) noexcept = 0;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/background_layer.hpp b/include/mbgl/style/layers/background_layer.hpp
index e188a9ba2c..b471d8613e 100644
--- a/include/mbgl/style/layers/background_layer.hpp
+++ b/include/mbgl/style/layers/background_layer.hpp
@@ -56,15 +56,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class BackgroundLayerFactory : public LayerFactory {
-public:
-    BackgroundLayerFactory();
-    ~BackgroundLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class BackgroundLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/circle_layer.hpp b/include/mbgl/style/layers/circle_layer.hpp
index 4dacb905df..46951653b7 100644
--- a/include/mbgl/style/layers/circle_layer.hpp
+++ b/include/mbgl/style/layers/circle_layer.hpp
@@ -104,15 +104,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class CircleLayerFactory : public LayerFactory {
-public:
-    CircleLayerFactory();
-    ~CircleLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class CircleLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/custom_layer.hpp b/include/mbgl/style/layers/custom_layer.hpp
index 5021df6a60..d204a782f2 100644
--- a/include/mbgl/style/layers/custom_layer.hpp
+++ b/include/mbgl/style/layers/custom_layer.hpp
@@ -85,15 +85,13 @@ public:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
+} // namespace style
+
 class CustomLayerFactory : public LayerFactory {
-public:
-    CustomLayerFactory();
     // LayerFactory overrides.
-    ~CustomLayerFactory() override;
-
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/fill_extrusion_layer.hpp b/include/mbgl/style/layers/fill_extrusion_layer.hpp
index 0092e61f3b..059b8f8996 100644
--- a/include/mbgl/style/layers/fill_extrusion_layer.hpp
+++ b/include/mbgl/style/layers/fill_extrusion_layer.hpp
@@ -80,15 +80,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class FillExtrusionLayerFactory : public LayerFactory {
-public:
-    FillExtrusionLayerFactory();
-    ~FillExtrusionLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class FillExtrusionLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/fill_layer.hpp b/include/mbgl/style/layers/fill_layer.hpp
index 52bbd054ae..222142daf3 100644
--- a/include/mbgl/style/layers/fill_layer.hpp
+++ b/include/mbgl/style/layers/fill_layer.hpp
@@ -80,15 +80,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class FillLayerFactory : public LayerFactory {
-public:
-    FillLayerFactory();
-    ~FillLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class FillLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/heatmap_layer.hpp b/include/mbgl/style/layers/heatmap_layer.hpp
index d1760100ad..004d77c487 100644
--- a/include/mbgl/style/layers/heatmap_layer.hpp
+++ b/include/mbgl/style/layers/heatmap_layer.hpp
@@ -69,15 +69,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class HeatmapLayerFactory : public LayerFactory {
-public:
-    HeatmapLayerFactory();
-    ~HeatmapLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class HeatmapLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/hillshade_layer.hpp b/include/mbgl/style/layers/hillshade_layer.hpp
index 978670f8a9..f840386907 100644
--- a/include/mbgl/style/layers/hillshade_layer.hpp
+++ b/include/mbgl/style/layers/hillshade_layer.hpp
@@ -74,15 +74,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class HillshadeLayerFactory : public LayerFactory {
-public:
-    HillshadeLayerFactory();
-    ~HillshadeLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class HillshadeLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/layer.hpp.ejs b/include/mbgl/style/layers/layer.hpp.ejs
index 11d45b4b0c..84a8edd9de 100644
--- a/include/mbgl/style/layers/layer.hpp.ejs
+++ b/include/mbgl/style/layers/layer.hpp.ejs
@@ -72,15 +72,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class <%- camelize(type) %>LayerFactory : public LayerFactory {
-public:
-    <%- camelize(type) %>LayerFactory();
-    ~<%- camelize(type) %>LayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class <%- camelize(type) %>LayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/line_layer.hpp b/include/mbgl/style/layers/line_layer.hpp
index 0f5e2bb347..bbc0213c53 100644
--- a/include/mbgl/style/layers/line_layer.hpp
+++ b/include/mbgl/style/layers/line_layer.hpp
@@ -125,15 +125,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class LineLayerFactory : public LayerFactory {
-public:
-    LineLayerFactory();
-    ~LineLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class LineLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/raster_layer.hpp b/include/mbgl/style/layers/raster_layer.hpp
index 4b63570590..0def2faacd 100644
--- a/include/mbgl/style/layers/raster_layer.hpp
+++ b/include/mbgl/style/layers/raster_layer.hpp
@@ -86,15 +86,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class RasterLayerFactory : public LayerFactory {
-public:
-    RasterLayerFactory();
-    ~RasterLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class RasterLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl
diff --git a/include/mbgl/style/layers/symbol_layer.hpp b/include/mbgl/style/layers/symbol_layer.hpp
index 62ea393b33..e17df295f3 100644
--- a/include/mbgl/style/layers/symbol_layer.hpp
+++ b/include/mbgl/style/layers/symbol_layer.hpp
@@ -274,15 +274,13 @@ protected:
     Mutable<Layer::Impl> mutableBaseImpl() const final;
 };
 
-class SymbolLayerFactory : public LayerFactory {
-public:
-    SymbolLayerFactory();
-    ~SymbolLayerFactory() override;
+} // namespace style
 
-    // LayerFactory overrides.
-    const LayerTypeInfo* getTypeInfo() const noexcept final;
-    std::unique_ptr<style::Layer> createLayer(const std::string& id, const conversion::Convertible& value) final;
+class SymbolLayerFactory : public LayerFactory {
+protected:
+    const style::LayerTypeInfo* getTypeInfo() const noexcept final;
+    std::unique_ptr<style::Layer> createLayer(const std::string& id, const style::conversion::Convertible& value) noexcept final;
+    std::unique_ptr<RenderLayer> createRenderLayer(Immutable<style::Layer::Impl>) noexcept final;
 };
 
-} // namespace style
 } // namespace mbgl