Replace compile-time polymorphism with runtime polymorphism in the conversion system

cmake/benchmark.cmake

@@ -19,6 +19,7 @@ target_link_libraries(mbgl-benchmark
 
 target_add_mason_package(mbgl-benchmark PRIVATE boost)
 target_add_mason_package(mbgl-benchmark PRIVATE benchmark)
+target_add_mason_package(mbgl-benchmark PRIVATE geojson)
 target_add_mason_package(mbgl-benchmark PRIVATE rapidjson)
 target_add_mason_package(mbgl-benchmark PRIVATE protozero)
 target_add_mason_package(mbgl-benchmark PRIVATE vector-tile)

cmake/core-files.cmake

@@ -370,16 +370,26 @@ set(MBGL_CORE_FILES
     include/mbgl/style/conversion/geojson_options.hpp
     include/mbgl/style/conversion/layer.hpp
     include/mbgl/style/conversion/light.hpp
-    include/mbgl/style/conversion/make_property_setters.hpp
     include/mbgl/style/conversion/position.hpp
-    include/mbgl/style/conversion/property_setter.hpp
     include/mbgl/style/conversion/property_value.hpp
     include/mbgl/style/conversion/source.hpp
     include/mbgl/style/conversion/tileset.hpp
     include/mbgl/style/conversion/transition_options.hpp
+    src/mbgl/style/conversion/constant.cpp
+    src/mbgl/style/conversion/coordinate.cpp
+    src/mbgl/style/conversion/filter.cpp
     src/mbgl/style/conversion/geojson.cpp
+    src/mbgl/style/conversion/geojson_options.cpp
     src/mbgl/style/conversion/json.hpp
+    src/mbgl/style/conversion/layer.cpp
+    src/mbgl/style/conversion/light.cpp
+    src/mbgl/style/conversion/make_property_setters.hpp
+    src/mbgl/style/conversion/position.cpp
+    src/mbgl/style/conversion/property_setter.hpp
+    src/mbgl/style/conversion/source.cpp
     src/mbgl/style/conversion/stringify.hpp
+    src/mbgl/style/conversion/tileset.cpp
+    src/mbgl/style/conversion/transition_options.cpp
 
     # style/function
     include/mbgl/style/function/camera_function.hpp

cmake/node.cmake

@@ -13,6 +13,7 @@ set_target_properties("mbgl-node" PROPERTIES CXX_STANDARD 14)
 target_sources(mbgl-node
     PRIVATE platform/node/src/node_logging.hpp
     PRIVATE platform/node/src/node_logging.cpp
+    PRIVATE platform/node/src/node_conversion.hpp
     PRIVATE platform/node/src/node_map.hpp
     PRIVATE platform/node/src/node_map.cpp
     PRIVATE platform/node/src/node_request.hpp

cmake/test-files.cmake

@@ -51,7 +51,6 @@ set(MBGL_TEST_FILES
     test/sprite/sprite_parser.test.cpp
 
     # src/mbgl/test
-    test/src/mbgl/test/conversion_stubs.hpp
     test/src/mbgl/test/fake_file_source.hpp
     test/src/mbgl/test/fixture_log_observer.cpp
     test/src/mbgl/test/fixture_log_observer.hpp

include/mbgl/style/conversion.hpp

@@ -1,6 +1,8 @@
 #pragma once
 
 #include <mbgl/util/optional.hpp>
+#include <mbgl/util/feature.hpp>
+#include <mbgl/util/geojson.hpp>
 
 #include <string>
 
@@ -9,9 +11,8 @@ namespace style {
 namespace conversion {
 
 /*
-   The `conversion` namespace defines conversions from a templated type `V` representing a JSON
-   object conforming to the schema defined by the Mapbox Style Specification, to the various C++
-   types that form the C++ model of that domain:
+   The `conversion` namespace defines conversions from JSON structures conforming to the schema defined by
+   the Mapbox Style Specification, to the various C++ types that form the C++ model of that domain:
 
        * `std::unique_ptr<Source>`
        * `std::unique_ptr<Layer>`
@@ -20,15 +21,31 @@ namespace conversion {
 
    A single template function serves as the public interface:
 
-       template <class T, class V>
-       optional<T> convert(const V& value, Error& error);
+       template <class T>
+       optional<T> convert(const Convertible& input, Error& error);
 
    Where `T` is one of the above types. If the conversion fails, the result is empty, and the
    error parameter includes diagnostic text suitable for presentation to a library user. Otherwise,
    a filled optional is returned.
 
-   The implementation of `convert` requires that the following are legal expressions for a value `v`
-   of type `const V&`:
+   `Convertible` is a type that encapsulates a special form of polymorphism over various underlying types that
+   can serve as input to the conversion algorithm. For instance, on macOS, we need to support
+   conversion from both RapidJSON types, and a JSON structure represented with `NSArray`/`NSDictionary`/etc.
+   On Qt, we need to support conversion from RapidJSON types and QVariant.
+
+   We don't want to use traditional forms of polymorphism to accomplish this:
+
+     * Compile time polymorphism using a template parameter for the actual value type leads to
+       excessive code bloat and long compile times.
+     * Runtime polymorphism using virtual methods requires extra heap allocation and ubiquitous
+       use of std::unique_ptr, unsuitable for this performance-sensitive code.
+
+   Therefore, we're using a custom implementation of runtime polymorphism where we manually create and
+   dispatch through a table of function pointers (vtable), while keeping the storage for any of the possible
+   underlying types inline on the stack, using `std::aligned_storage`.
+
+   For a given underlying type T, an explicit specialization of `ConversionTraits<T>` must be provided. This
+   specialization must provide the following static methods:
 
       * `isUndefined(v)` -- returns a boolean indication whether `v` is undefined or a JSON null
 
@@ -48,21 +65,234 @@ namespace conversion {
       * `toNumber(v)` -- returns `optional<float>`, absence indicating `v` is not a JSON number
       * `toDouble(v)` -- returns `optional<double>`, absence indicating `v` is not a JSON number
       * `toString(v)` -- returns `optional<std::string>`, absence indicating `v` is not a JSON string
-      * `toValue(v)` -- returns `optional<mbgl::Value>`, a variant type, for generic conversion,
+      * `toValue(v)` -- returns `optional<Value>`, a variant type, for generic conversion,
         absence indicating `v` is not a boolean, number, or string. Numbers should be converted to
         unsigned integer, signed integer, or floating point, in descending preference.
 
-   The mbgl core implements these requirements for RapidJSON types, and the node bindings implement
-   them for v8 types.
+   In addition, the type T must be move-constructable. And finally, `Convertible::Storage`, a typedef for
+   `std::aligned_storage_t`, must be large enough to satisfy the memory requirements for any of the
+   possible underlying types. (A static assert will fail if this is not the case.)
+
+   `Convertible` itself is movable, but not copyable. A moved-from `Convertible` is in an invalid state;
+   you must not do anything with it except let it go out of scope.
 */
 
 struct Error { std::string message; };
 
+template <typename T>
+class ConversionTraits;
+
+class Convertible {
+public:
+    template <typename T>
+    Convertible(T&& value) : vtable(vtableForType<std::decay_t<T>>()) {
+        static_assert(sizeof(Storage) >= sizeof(std::decay_t<T>), "Storage must be large enough to hold value type");
+        new (static_cast<void*>(&storage)) std::decay_t<T>(std::forward<T>(value));
+    }
+
+    Convertible(Convertible&& v)
+        : vtable(v.vtable)
+    {
+        if (vtable) {
+            vtable->move(std::move(v.storage), this->storage);
+        }
+    }
+
+    ~Convertible() {
+        if (vtable) {
+            vtable->destroy(storage);
+        }
+    }
+
+    Convertible& operator=(Convertible&& v) {
+        if (vtable) {
+            vtable->destroy(storage);
+        }
+        vtable = v.vtable;
+        if (vtable) {
+            vtable->move(std::move(v.storage), this->storage);
+        }
+        v.vtable = nullptr;
+        return *this;
+    }
+
+    Convertible()                              = delete;
+    Convertible(const Convertible&)            = delete;
+    Convertible& operator=(const Convertible&) = delete;
+
+    friend inline bool isUndefined(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->isUndefined(v.storage);
+    }
+
+    friend inline bool isArray(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->isArray(v.storage);
+    }
+
+    friend inline std::size_t arrayLength(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->arrayLength(v.storage);
+    }
+
+    friend inline Convertible arrayMember(const Convertible& v, std::size_t i) {
+        assert(v.vtable);
+        return v.vtable->arrayMember(v.storage, i);
+    }
+
+    friend inline bool isObject(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->isObject(v.storage);
+    }
+
+    friend inline optional<Convertible> objectMember(const Convertible& v, const char * name) {
+        assert(v.vtable);
+        return v.vtable->objectMember(v.storage, name);
+    }
+
+    friend inline optional<Error> eachMember(const Convertible& v, const std::function<optional<Error> (const std::string&, const Convertible&)>& fn) {
+        assert(v.vtable);
+        return v.vtable->eachMember(v.storage, fn);
+    }
+
+    friend inline optional<bool> toBool(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->toBool(v.storage);
+    }
+
+    friend inline optional<float> toNumber(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->toNumber(v.storage);
+    }
+
+    friend inline optional<double> toDouble(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->toDouble(v.storage);
+    }
+
+    friend inline optional<std::string> toString(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->toString(v.storage);
+    }
+
+    friend inline optional<Value> toValue(const Convertible& v) {
+        assert(v.vtable);
+        return v.vtable->toValue(v.storage);
+    }
+
+    friend inline optional<GeoJSON> toGeoJSON(const Convertible& v, Error& error) {
+        assert(v.vtable);
+        return v.vtable->toGeoJSON(v.storage, error);
+    }
+
+private:
+#if __ANDROID__
+    // Android:     JSValue* or mbgl::android::Value
+    using Storage = std::aligned_storage_t<32, 8>;
+#elif __QT__
+    // Qt:          JSValue* or QVariant
+    using Storage = std::aligned_storage_t<32, 8>;
+#else
+    // Node:        JSValue* or v8::Local<v8::Value>
+    // iOS/macOS:   JSValue* or id
+    using Storage = std::aligned_storage_t<8, 8>;
+#endif
+
+    struct VTable {
+        void (*move) (Storage&& src, Storage& dest);
+        void (*destroy) (Storage&);
+
+        bool (*isUndefined) (const Storage&);
+
+        bool        (*isArray)     (const Storage&);
+        std::size_t (*arrayLength) (const Storage&);
+        Convertible (*arrayMember) (const Storage&, std::size_t);
+
+        bool                  (*isObject)     (const Storage&);
+        optional<Convertible> (*objectMember) (const Storage&, const char *);
+        optional<Error>       (*eachMember)   (const Storage&, const std::function<optional<Error> (const std::string&, const Convertible&)>&);
+
+        optional<bool>        (*toBool)   (const Storage&);
+        optional<float>       (*toNumber) (const Storage&);
+        optional<double>      (*toDouble) (const Storage&);
+        optional<std::string> (*toString) (const Storage&);
+        optional<Value>       (*toValue)  (const Storage&);
+
+        // https://github.com/mapbox/mapbox-gl-native/issues/5623
+        optional<GeoJSON> (*toGeoJSON) (const Storage&, Error&);
+    };
+
+    template <typename T>
+    static VTable* vtableForType() {
+        using Traits = ConversionTraits<T>;
+        static VTable vtable = {
+            [] (Storage&& src, Storage& dest) {
+                auto srcValue = reinterpret_cast<T&&>(src);
+                new (static_cast<void*>(&dest)) T(std::move(srcValue));
+                srcValue.~T();
+            },
+            [] (Storage& s) {
+                reinterpret_cast<T&>(s).~T();
+            },
+            [] (const Storage& s) {
+                return Traits::isUndefined(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s) {
+                return Traits::isArray(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s) {
+                return Traits::arrayLength(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s, std::size_t i) {
+                return Convertible(Traits::arrayMember(reinterpret_cast<const T&>(s), i));
+            },
+            [] (const Storage& s) {
+                return Traits::isObject(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s, const char * key) {
+                optional<T> member = Traits::objectMember(reinterpret_cast<const T&>(s), key);
+                if (member) {
+                    return optional<Convertible>(Convertible(std::move(*member)));
+                } else {
+                    return optional<Convertible>();
+                }
+            },
+            [] (const Storage& s, const std::function<optional<Error> (const std::string&, const Convertible&)>& fn) {
+                return Traits::eachMember(reinterpret_cast<const T&>(s), [&](const std::string& k, T&& v) {
+                    return fn(k, Convertible(std::move(v)));
+                });
+            },
+            [] (const Storage& s) {
+                return Traits::toBool(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s) {
+                return Traits::toNumber(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s) {
+                return Traits::toDouble(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s) {
+                return Traits::toString(reinterpret_cast<const T&>(s));
+            },
+            []  (const Storage& s) {
+                return Traits::toValue(reinterpret_cast<const T&>(s));
+            },
+            [] (const Storage& s, Error& err) {
+                return Traits::toGeoJSON(reinterpret_cast<const T&>(s), err);
+            }
+        };
+        return &vtable;
+    }
+
+    VTable* vtable;
+    Storage storage;
+};
+
 template <class T, class Enable = void>
 struct Converter;
 
-template <class T, class V, class...Args>
-optional<T> convert(const V& value, Error& error, Args&&...args) {
+template <class T, class...Args>
+optional<T> convert(const Convertible& value, Error& error, Args&&...args) {
     return Converter<T>()(value, error, std::forward<Args>(args)...);
 }
 

include/mbgl/style/conversion/constant.hpp

@@ -1,7 +1,6 @@
 #pragma once
 
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/util/optional.hpp>
 #include <mbgl/util/color.hpp>
 #include <mbgl/util/enum.hpp>
 #include <mbgl/util/string.hpp>
@@ -16,47 +15,22 @@ namespace conversion {
 
 template <>
 struct Converter<bool> {
-    template <class V>
-    optional<bool> operator()(const V& value, Error& error) const {
-        optional<bool> converted = toBool(value);
-        if (!converted) {
-            error = { "value must be a boolean" };
-            return {};
-        }
-        return *converted;
-    }
+    optional<bool> operator()(const Convertible& value, Error& error) const;
 };
 
 template <>
 struct Converter<float> {
-    template <class V>
-    optional<float> operator()(const V& value, Error& error) const {
-        optional<float> converted = toNumber(value);
-        if (!converted) {
-            error = { "value must be a number" };
-            return {};
-        }
-        return *converted;
-    }
+    optional<float> operator()(const Convertible& value, Error& error) const;
 };
 
 template <>
 struct Converter<std::string> {
-    template <class V>
-    optional<std::string> operator()(const V& value, Error& error) const {
-        optional<std::string> converted = toString(value);
-        if (!converted) {
-            error = { "value must be a string" };
-            return {};
-        }
-        return *converted;
-    }
+    optional<std::string> operator()(const Convertible& value, Error& error) const;
 };
 
 template <class T>
 struct Converter<T, typename std::enable_if_t<std::is_enum<T>::value>> {
-    template <class V>
-    optional<T> operator()(const V& value, Error& error) const {
+    optional<T> operator()(const Convertible& value, Error& error) const {
         optional<std::string> string = toString(value);
         if (!string) {
             error = { "value must be a string" };
@@ -75,28 +49,12 @@ struct Converter<T, typename std::enable_if_t<std::is_enum<T>::value>> {
 
 template <>
 struct Converter<Color> {
-    template <class V>
-    optional<Color> operator()(const V& value, Error& error) const {
-        optional<std::string> string = toString(value);
-        if (!string) {
-            error = { "value must be a string" };
-            return {};
-        }
-
-        optional<Color> color = Color::parse(*string);
-        if (!color) {
-            error = { "value must be a valid color" };
-            return {};
-        }
-
-        return *color;
-    }
+    optional<Color> operator()(const Convertible& value, Error& error) const;
 };
 
 template <size_t N>
 struct Converter<std::array<float, N>> {
-    template <class V>
-    optional<std::array<float, N>> operator()(const V& value, Error& error) const {
+    optional<std::array<float, N>> operator()(const Convertible& value, Error& error) const {
         if (!isArray(value) || arrayLength(value) != N) {
             error = { "value must be an array of " + util::toString(N) + " numbers" };
             return {};
@@ -117,52 +75,12 @@ struct Converter<std::array<float, N>> {
 
 template <>
 struct Converter<std::vector<float>> {
-    template <class V>
-    optional<std::vector<float>> operator()(const V& value, Error& error) const {
-        if (!isArray(value)) {
-            error = { "value must be an array" };
-            return {};
-        }
-
-        std::vector<float> result;
-        result.reserve(arrayLength(value));
-
-        for (std::size_t i = 0; i < arrayLength(value); ++i) {
-            optional<float> number = toNumber(arrayMember(value, i));
-            if (!number) {
-                error = { "value must be an array of numbers" };
-                return {};
-            }
-            result.push_back(*number);
-        }
-
-        return result;
-    }
+    optional<std::vector<float>> operator()(const Convertible& value, Error& error) const;
 };
 
 template <>
 struct Converter<std::vector<std::string>> {
-    template <class V>
-    optional<std::vector<std::string>> operator()(const V& value, Error& error) const {
-        if (!isArray(value)) {
-            error = { "value must be an array" };
-            return {};
-        }
-
-        std::vector<std::string> result;
-        result.reserve(arrayLength(value));
-
-        for (std::size_t i = 0; i < arrayLength(value); ++i) {
-            optional<std::string> string = toString(arrayMember(value, i));
-            if (!string) {
-                error = { "value must be an array of strings" };
-                return {};
-            }
-            result.push_back(*string);
-        }
-
-        return result;
-    }
+    optional<std::vector<std::string>> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/coordinate.hpp

@@ -10,26 +10,7 @@ namespace conversion {
 template<>
 struct Converter<LatLng> {
 public:
-    template <class V>
-    optional<LatLng> operator() (const V& value, Error& error) const {
-        if (!isArray(value) || arrayLength(value) < 2 ) {
-            error = { "coordinate array must contain numeric longitude and latitude values" };
-            return {};
-        }
-        //Style spec uses GeoJSON convention for specifying coordinates
-        optional<double> latitude = toDouble(arrayMember(value, 1));
-        optional<double> longitude = toDouble(arrayMember(value, 0));
-    
-        if (!latitude || !longitude) {
-            error = { "coordinate array must contain numeric longitude and latitude values" };
-            return {};
-        }
-        if (*latitude < -90 || *latitude > 90 ){
-            error = { "coordinate latitude must be between -90 and 90" };
-            return {};
-        }
-        return LatLng(*latitude, *longitude);
-    }
+    optional<LatLng> operator() (const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/data_driven_property_value.hpp

@@ -11,8 +11,7 @@ namespace conversion {
 
 template <class T>
 struct Converter<DataDrivenPropertyValue<T>> {
-    template <class V>
-    optional<DataDrivenPropertyValue<T>> operator()(const V& value, Error& error) const {
+    optional<DataDrivenPropertyValue<T>> operator()(const Convertible& value, Error& error) const {
         if (isUndefined(value)) {
             return DataDrivenPropertyValue<T>();
         } else if (!isObject(value)) {

include/mbgl/style/conversion/filter.hpp

@@ -2,7 +2,6 @@
 
 #include <mbgl/style/filter.hpp>
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/util/geometry.hpp>
 
 namespace mbgl {
 namespace style {
@@ -11,247 +10,7 @@ namespace conversion {
 template <>
 struct Converter<Filter> {
 public:
-    template <class V>
-    optional<Filter> operator()(const V& value, Error& error) const {
-        if (!isArray(value)) {
-            error = { "filter expression must be an array" };
-            return {};
-        }
-
-        if (arrayLength(value) < 1) {
-            error = { "filter expression must have at least 1 element" };
-            return {};
-        }
-
-        optional<std::string> op = toString(arrayMember(value, 0));
-        if (!op) {
-            error = { "filter operator must be a string" };
-            return {};
-        }
-
-        if (*op == "==") {
-            return convertEqualityFilter<EqualsFilter, TypeEqualsFilter, IdentifierEqualsFilter>(value, error);
-        } else if (*op == "!=") {
-            return convertEqualityFilter<NotEqualsFilter, TypeNotEqualsFilter, IdentifierNotEqualsFilter>(value, error);
-        } else if (*op == ">") {
-            return convertBinaryFilter<GreaterThanFilter>(value, error);
-        } else if (*op == ">=") {
-            return convertBinaryFilter<GreaterThanEqualsFilter>(value, error);
-        } else if (*op == "<") {
-            return convertBinaryFilter<LessThanFilter>(value, error);
-        } else if (*op == "<=") {
-            return convertBinaryFilter<LessThanEqualsFilter>(value, error);
-        } else if (*op == "in") {
-            return convertSetFilter<InFilter, TypeInFilter, IdentifierInFilter>(value, error);
-        } else if (*op == "!in") {
-            return convertSetFilter<NotInFilter, TypeNotInFilter, IdentifierNotInFilter>(value, error);
-        } else if (*op == "all") {
-            return convertCompoundFilter<AllFilter>(value, error);
-        } else if (*op == "any") {
-            return convertCompoundFilter<AnyFilter>(value, error);
-        } else if (*op == "none") {
-            return convertCompoundFilter<NoneFilter>(value, error);
-        } else if (*op == "has") {
-            return convertUnaryFilter<HasFilter, HasIdentifierFilter>(value, error);
-        } else if (*op == "!has") {
-           return convertUnaryFilter<NotHasFilter, NotHasIdentifierFilter>(value, error);
-        }
-
-        error = { R"(filter operator must be one of "==", "!=", ">", ">=", "<", "<=", "in", "!in", "all", "any", "none", "has", or "!has")" };
-        return {};
-    }
-
-private:
-    optional<Value> normalizeValue(const optional<Value>& value, Error& error) const {
-        if (!value) {
-            error = { "filter expression value must be a boolean, number, or string" };
-            return {};
-        } else {
-            return *value;
-        }
-    }
-
-    template <class V>
-    optional<FeatureType> toFeatureType(const V& value, Error& error) const {
-        optional<std::string> type = toString(value);
-        if (!type) {
-            error = { "value for $type filter must be a string" };
-            return {};
-        } else if (*type == "Point") {
-            return FeatureType::Point;
-        } else if (*type == "LineString") {
-            return FeatureType::LineString;
-        } else if (*type == "Polygon") {
-            return FeatureType::Polygon;
-        } else {
-            error = { "value for $type filter must be Point, LineString, or Polygon" };
-            return {};
-        }
-    }
-
-    template <class V>
-    optional<FeatureIdentifier> toFeatureIdentifier(const V& value, Error& error) const {
-        optional<Value> identifier = toValue(value);
-        if (!identifier) {
-            error = { "filter expression value must be a boolean, number, or string" };
-            return {};
-        } else {
-            return (*identifier).match(
-                [] (uint64_t t) -> optional<FeatureIdentifier> { return { t }; },
-                [] ( int64_t t) -> optional<FeatureIdentifier> { return { t }; },
-                [] (  double t) -> optional<FeatureIdentifier> { return { t }; },
-                [] (const std::string& t) -> optional<FeatureIdentifier> { return { t }; },
-                [&] (const auto&) -> optional<FeatureIdentifier> {
-                    error = { "filter expression value must be a boolean, number, or string" };
-                    return {};
-                });
-        }
-    }
-
-    template <class FilterType, class IdentifierFilterType, class V>
-    optional<Filter> convertUnaryFilter(const V& value, Error& error) const {
-        if (arrayLength(value) < 2) {
-            error = { "filter expression must have 2 elements" };
-            return {};
-        }
-
-        optional<std::string> key = toString(arrayMember(value, 1));
-        if (!key) {
-            error = { "filter expression key must be a string" };
-            return {};
-        }
-
-        if (*key == "$id") {
-            return { IdentifierFilterType {} };
-        } else {
-            return { FilterType { *key } };
-        }
-    }
-
-    template <class FilterType, class TypeFilterType, class IdentifierFilterType, class V>
-    optional<Filter> convertEqualityFilter(const V& value, Error& error) const {
-        if (arrayLength(value) < 3) {
-            error = { "filter expression must have 3 elements" };
-            return {};
-        }
-
-        optional<std::string> key = toString(arrayMember(value, 1));
-        if (!key) {
-            error = { "filter expression key must be a string" };
-            return {};
-        }
-
-        if (*key == "$type") {
-            optional<FeatureType> filterValue = toFeatureType(arrayMember(value, 2), error);
-            if (!filterValue) {
-                return {};
-            }
-
-            return { TypeFilterType { *filterValue } };
-
-        } else if (*key == "$id") {
-            optional<FeatureIdentifier> filterValue = toFeatureIdentifier(arrayMember(value, 2), error);
-            if (!filterValue) {
-                return {};
-            }
-
-            return { IdentifierFilterType { *filterValue } };
-
-        } else {
-            optional<Value> filterValue = normalizeValue(toValue(arrayMember(value, 2)), error);
-            if (!filterValue) {
-                return {};
-            }
-
-            return { FilterType { *key, *filterValue } };
-        }
-    }
-
-    template <class FilterType, class V>
-    optional<Filter> convertBinaryFilter(const V& value, Error& error) const {
-        if (arrayLength(value) < 3) {
-            error = { "filter expression must have 3 elements" };
-            return {};
-        }
-
-        optional<std::string> key = toString(arrayMember(value, 1));
-        if (!key) {
-            error = { "filter expression key must be a string" };
-            return {};
-        }
-
-        optional<Value> filterValue = normalizeValue(toValue(arrayMember(value, 2)), error);
-        if (!filterValue) {
-            return {};
-        }
-
-        return { FilterType { *key, *filterValue } };
-    }
-
-    template <class FilterType, class TypeFilterType, class IdentifierFilterType, class V>
-    optional<Filter> convertSetFilter(const V& value, Error& error) const {
-        if (arrayLength(value) < 2) {
-            error = { "filter expression must at least 2 elements" };
-            return {};
-        }
-
-        optional<std::string> key = toString(arrayMember(value, 1));
-        if (!key) {
-            error = { "filter expression key must be a string" };
-            return {};
-        }
-
-        if (*key == "$type") {
-            std::vector<FeatureType> values;
-            for (std::size_t i = 2; i < arrayLength(value); ++i) {
-                optional<FeatureType> filterValue = toFeatureType(arrayMember(value, i), error);
-                if (!filterValue) {
-                    return {};
-                }
-                values.push_back(*filterValue);
-            }
-
-            return { TypeFilterType { std::move(values) } };
-
-        } else if (*key == "$id") {
-            std::vector<FeatureIdentifier> values;
-            for (std::size_t i = 2; i < arrayLength(value); ++i) {
-                optional<FeatureIdentifier> filterValue = toFeatureIdentifier(arrayMember(value, i), error);
-                if (!filterValue) {
-                    return {};
-                }
-                values.push_back(*filterValue);
-            }
-
-            return { IdentifierFilterType { std::move(values) } };
-
-        } else {
-            std::vector<Value> values;
-            for (std::size_t i = 2; i < arrayLength(value); ++i) {
-                optional<Value> filterValue = normalizeValue(toValue(arrayMember(value, i)), error);
-                if (!filterValue) {
-                    return {};
-                }
-                values.push_back(*filterValue);
-            }
-
-            return { FilterType { *key, std::move(values) } };
-        }
-    }
-
-    template <class FilterType, class V>
-    optional<Filter> convertCompoundFilter(const V& value, Error& error) const {
-        std::vector<Filter> filters;
-        for (std::size_t i = 1; i < arrayLength(value); ++i) {
-            optional<Filter> element = operator()(arrayMember(value, i), error);
-            if (!element) {
-                return {};
-            }
-            filters.push_back(*element);
-        }
-
-        return { FilterType { std::move(filters) } };
-    }
+    optional<Filter> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/function.hpp

@@ -11,8 +11,8 @@ namespace mbgl {
 namespace style {
 namespace conversion {
 
-template <class D, class R, class V>
-optional<std::map<D, R>> convertStops(const V& value, Error& error) {
+template <class D, class R>
+optional<std::map<D, R>> convertStops(const Convertible& value, Error& error) {
     auto stopsValue = objectMember(value, "stops");
     if (!stopsValue) {
         error = { "function value must specify stops" };
@@ -63,8 +63,7 @@ template <class T>
 struct Converter<ExponentialStops<T>> {
     static constexpr const char * type = "exponential";
 
-    template <class V>
-    optional<ExponentialStops<T>> operator()(const V& value, Error& error) const {
+    optional<ExponentialStops<T>> operator()(const Convertible& value, Error& error) const {
         auto stops = convertStops<float, T>(value, error);
         if (!stops) {
             return {};
@@ -89,8 +88,7 @@ template <class T>
 struct Converter<IntervalStops<T>> {
     static constexpr const char * type = "interval";
 
-    template <class V>
-    optional<IntervalStops<T>> operator()(const V& value, Error& error) const {
+    optional<IntervalStops<T>> operator()(const Convertible& value, Error& error) const {
         auto stops = convertStops<float, T>(value, error);
         if (!stops) {
             return {};
@@ -101,8 +99,7 @@ struct Converter<IntervalStops<T>> {
 
 template <>
 struct Converter<CategoricalValue> {
-    template <class V>
-    optional<CategoricalValue> operator()(const V& value, Error& error) const {
+    optional<CategoricalValue> operator()(const Convertible& value, Error& error) const {
         auto b = toBool(value);
         if (b) {
             return { *b };
@@ -127,8 +124,7 @@ template <class T>
 struct Converter<CategoricalStops<T>> {
     static constexpr const char * type = "categorical";
 
-    template <class V>
-    optional<CategoricalStops<T>> operator()(const V& value, Error& error) const {
+    optional<CategoricalStops<T>> operator()(const Convertible& value, Error& error) const {
         auto stops = convertStops<CategoricalValue, T>(value, error);
         if (!stops) {
             return {};
@@ -142,8 +138,7 @@ template <class T>
 struct Converter<IdentityStops<T>> {
     static constexpr const char * type = "identity";
 
-    template <class V>
-    optional<IdentityStops<T>> operator()(const V&, Error&) const {
+    optional<IdentityStops<T>> operator()(const Convertible&, Error&) const {
         return IdentityStops<T>();
     }
 };
@@ -154,8 +149,7 @@ struct StopsConverter;
 template <class T, class... Ts>
 struct StopsConverter<T, variant<Ts...>> {
 public:
-    template <class V>
-    optional<variant<Ts...>> operator()(const V& value, Error& error) const {
+    optional<variant<Ts...>> operator()(const Convertible& value, Error& error) const {
         std::string type = util::Interpolatable<T>::value ? "exponential" : "interval";
 
         auto typeValue = objectMember(value, "type");
@@ -193,8 +187,7 @@ public:
 
 template <class T>
 struct Converter<CameraFunction<T>> {
-    template <class V>
-    optional<CameraFunction<T>> operator()(const V& value, Error& error) const {
+    optional<CameraFunction<T>> operator()(const Convertible& value, Error& error) const {
         if (!isObject(value)) {
             error = { "function must be an object" };
             return {};
@@ -209,8 +202,8 @@ struct Converter<CameraFunction<T>> {
     }
 };
 
-template <class T, class V>
-optional<optional<T>> convertDefaultValue(const V& value, Error& error) {
+template <class T>
+optional<optional<T>> convertDefaultValue(const Convertible& value, Error& error) {
     auto defaultValueValue = objectMember(value, "default");
     if (!defaultValueValue) {
         return optional<T>();
@@ -227,8 +220,7 @@ optional<optional<T>> convertDefaultValue(const V& value, Error& error) {
 
 template <class T>
 struct Converter<SourceFunction<T>> {
-    template <class V>
-    optional<SourceFunction<T>> operator()(const V& value, Error& error) const {
+    optional<SourceFunction<T>> operator()(const Convertible& value, Error& error) const {
         if (!isObject(value)) {
             error = { "function must be an object" };
             return {};
@@ -267,8 +259,7 @@ struct CompositeValue : std::pair<float, S> {
 
 template <class S>
 struct Converter<CompositeValue<S>> {
-    template <class V>
-    optional<CompositeValue<S>> operator()(const V& value, Error& error) const {
+    optional<CompositeValue<S>> operator()(const Convertible& value, Error& error) const {
         if (!isObject(value)) {
             error = { "stop must be an object" };
             return {};
@@ -304,8 +295,7 @@ template <class T>
 struct Converter<CompositeExponentialStops<T>> {
     static constexpr const char * type = "exponential";
 
-    template <class V>
-    optional<CompositeExponentialStops<T>> operator()(const V& value, Error& error) const {
+    optional<CompositeExponentialStops<T>> operator()(const Convertible& value, Error& error) const {
         auto stops = convertStops<CompositeValue<float>, T>(value, error);
         if (!stops) {
             return {};
@@ -330,8 +320,7 @@ template <class T>
 struct Converter<CompositeIntervalStops<T>> {
     static constexpr const char * type = "interval";
 
-    template <class V>
-    optional<CompositeIntervalStops<T>> operator()(const V& value, Error& error) const {
+    optional<CompositeIntervalStops<T>> operator()(const Convertible& value, Error& error) const {
         auto stops = convertStops<CompositeValue<float>, T>(value, error);
         if (!stops) {
             return {};
@@ -350,8 +339,7 @@ template <class T>
 struct Converter<CompositeCategoricalStops<T>> {
     static constexpr const char * type = "categorical";
 
-    template <class V>
-    optional<CompositeCategoricalStops<T>> operator()(const V& value, Error& error) const {
+    optional<CompositeCategoricalStops<T>> operator()(const Convertible& value, Error& error) const {
         auto stops = convertStops<CompositeValue<CategoricalValue>, T>(value, error);
         if (!stops) {
             return {};
@@ -368,8 +356,7 @@ struct Converter<CompositeCategoricalStops<T>> {
 
 template <class T>
 struct Converter<CompositeFunction<T>> {
-    template <class V>
-    optional<CompositeFunction<T>> operator()(const V& value, Error& error) const {
+    optional<CompositeFunction<T>> operator()(const Convertible& value, Error& error) const {
         if (!isObject(value)) {
             error = { "function must be an object" };
             return {};

include/mbgl/style/conversion/geojson.hpp

@@ -7,15 +7,13 @@ namespace mbgl {
 namespace style {
 namespace conversion {
 
+// Workaround until https://github.com/mapbox/mapbox-gl-native/issues/5623 is done.
+optional<GeoJSON> parseGeoJSON(const std::string&, Error&);
+
 template <>
 struct Converter<GeoJSON> {
 public:
-    optional<GeoJSON> operator()(const std::string&, Error&) const;
-
-    // This is explicitly specialized in the .cpp file for JSValue. It may also be explicitly
-    // specialized for SDK-specific types (e.g. mbgl::android::Value).
-    template <class V>
-    optional<GeoJSON> operator()(const V&, Error&) const;
+    optional<GeoJSON> operator()(const Convertible&, Error&) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/geojson_options.hpp

@@ -9,84 +9,7 @@ namespace conversion {
 
 template <>
 struct Converter<GeoJSONOptions> {
-
-    template <class V>
-    optional<GeoJSONOptions> operator()(const V& value, Error& error) const {
-        GeoJSONOptions options;
-
-        const auto minzoomValue = objectMember(value, "minzoom");
-        if (minzoomValue) {
-            if (toNumber(*minzoomValue)) {
-                options.minzoom = static_cast<uint8_t>(*toNumber(*minzoomValue));
-            } else {
-                error = { "GeoJSON source minzoom value must be a number" };
-                return {};
-            }
-        }
-
-        const auto maxzoomValue = objectMember(value, "maxzoom");
-        if (maxzoomValue) {
-            if (toNumber(*maxzoomValue)) {
-                options.maxzoom = static_cast<uint8_t>(*toNumber(*maxzoomValue));
-            } else {
-                error = { "GeoJSON source maxzoom value must be a number" };
-                return {};
-            }
-        }
-
-        const auto bufferValue = objectMember(value, "buffer");
-        if (bufferValue) {
-            if (toNumber(*bufferValue)) {
-                options.buffer = static_cast<uint16_t>(*toNumber(*bufferValue));
-            } else {
-                error = { "GeoJSON source buffer value must be a number" };
-                return {};
-            }
-        }
-
-        const auto toleranceValue = objectMember(value, "tolerance");
-        if (toleranceValue) {
-            if (toNumber(*toleranceValue)) {
-                options.tolerance = static_cast<double>(*toNumber(*toleranceValue));
-            } else {
-                error = { "GeoJSON source tolerance value must be a number" };
-                return {};
-            }
-        }
-
-        const auto clusterValue = objectMember(value, "cluster");
-        if (clusterValue) {
-            if (toBool(*clusterValue)) {
-                options.cluster = *toBool(*clusterValue);
-            } else {
-                error = { "GeoJSON source cluster value must be a boolean" };
-                return {};
-            }
-        }
-
-        const auto clusterMaxZoomValue = objectMember(value, "clusterMaxZoom");
-        if (clusterMaxZoomValue) {
-            if (toNumber(*clusterMaxZoomValue)) {
-                options.clusterMaxZoom = static_cast<uint8_t>(*toNumber(*clusterMaxZoomValue));
-            } else {
-                error = { "GeoJSON source clusterMaxZoom value must be a number" };
-                return {};
-            }
-        }
-
-        const auto clusterRadiusValue = objectMember(value, "clusterRadius");
-        if (clusterRadiusValue) {
-            if (toNumber(*clusterRadiusValue)) {
-                options.clusterRadius = static_cast<double>(*toNumber(*clusterRadiusValue));
-            } else {
-                error = { "GeoJSON source clusterRadius value must be a number" };
-                return {};
-            }
-        }
-
-        return { options };
-    }
-
+    optional<GeoJSONOptions> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/layer.hpp

@@ -1,220 +1,24 @@
 #pragma once
 
 #include <mbgl/style/layer.hpp>
-#include <mbgl/style/layers/background_layer.hpp>
-#include <mbgl/style/layers/circle_layer.hpp>
-#include <mbgl/style/layers/fill_layer.hpp>
-#include <mbgl/style/layers/fill_extrusion_layer.hpp>
-#include <mbgl/style/layers/line_layer.hpp>
-#include <mbgl/style/layers/raster_layer.hpp>
-#include <mbgl/style/layers/symbol_layer.hpp>
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/style/conversion/constant.hpp>
-#include <mbgl/style/conversion/filter.hpp>
-#include <mbgl/style/conversion/make_property_setters.hpp>
+
+#include <memory>
 
 namespace mbgl {
 namespace style {
 namespace conversion {
 
-template <class V>
-optional<Error> setLayoutProperty(Layer& layer, const std::string& name, const V& value) {
-    static const auto setters = makeLayoutPropertySetters<V>();
-    auto it = setters.find(name);
-    if (it == setters.end()) {
-        return Error { "property not found" };
-    }
-    return it->second(layer, value);
-}
-
-template <class V>
-optional<Error> setPaintProperty(Layer& layer, const std::string& name, const V& value) {
-    static const auto setters = makePaintPropertySetters<V>();
-    auto it = setters.find(name);
-    if (it == setters.end()) {
-        return Error { "property not found" };
-    }
-    return it->second(layer, value);
-}
-
-template <class V>
-optional<Error> setPaintProperties(Layer& layer, const V& value) {
-    auto paintValue = objectMember(value, "paint");
-    if (!paintValue) {
-        return {};
-    }
-    return eachMember(*paintValue, [&] (const std::string& k, const V& v) {
-        return setPaintProperty(layer, k, v);
-    });
-}
-
 template <>
 struct Converter<std::unique_ptr<Layer>> {
 public:
-    template <class V>
-    optional<std::unique_ptr<Layer>> operator()(const V& value, Error& error) const {
-        if (!isObject(value)) {
-            error = { "layer must be an object" };
-            return {};
-        }
-
-        auto idValue = objectMember(value, "id");
-        if (!idValue) {
-            error = { "layer must have an id" };
-            return {};
-        }
-
-        optional<std::string> id = toString(*idValue);
-        if (!id) {
-            error = { "layer id must be a string" };
-            return {};
-        }
-
-        auto typeValue = objectMember(value, "type");
-        if (!typeValue) {
-            error = { "layer must have a type" };
-            return {};
-        }
-
-        optional<std::string> type = toString(*typeValue);
-        if (!type) {
-            error = { "layer type must be a string" };
-            return {};
-        }
-
-        optional<std::unique_ptr<Layer>> converted;
-
-        if (*type == "fill") {
-            converted = convertVectorLayer<FillLayer>(*id, value, error);
-        } else if (*type == "fill-extrusion") {
-            converted = convertVectorLayer<FillExtrusionLayer>(*id, value, error);
-        } else if (*type == "line") {
-            converted = convertVectorLayer<LineLayer>(*id, value, error);
-        } else if (*type == "circle") {
-            converted = convertVectorLayer<CircleLayer>(*id, value, error);
-        } else if (*type == "symbol") {
-            converted = convertVectorLayer<SymbolLayer>(*id, value, error);
-        } else if (*type == "raster") {
-            converted = convertRasterLayer(*id, value, error);
-        } else if (*type == "background") {
-            converted = convertBackgroundLayer(*id, value, error);
-        } else {
-            error = { "invalid layer type" };
-            return {};
-        }
-
-        if (!converted) {
-            return converted;
-        }
-
-        std::unique_ptr<Layer> layer = std::move(*converted);
-
-        auto minzoomValue = objectMember(value, "minzoom");
-        if (minzoomValue) {
-            optional<float> minzoom = toNumber(*minzoomValue);
-            if (!minzoom) {
-                error = { "minzoom must be numeric" };
-                return {};
-            }
-            layer->setMinZoom(*minzoom);
-        }
-
-        auto maxzoomValue = objectMember(value, "maxzoom");
-        if (maxzoomValue) {
-            optional<float> maxzoom = toNumber(*maxzoomValue);
-            if (!maxzoom) {
-                error = { "maxzoom must be numeric" };
-                return {};
-            }
-            layer->setMaxZoom(*maxzoom);
-        }
-
-        auto layoutValue = objectMember(value, "layout");
-        if (layoutValue) {
-            if (!isObject(*layoutValue)) {
-                error = { "layout must be an object" };
-                return {};
-            }
-            optional<Error> error_ = eachMember(*layoutValue, [&] (const std::string& k, const V& v) {
-                return setLayoutProperty(*layer, k, v);
-            });
-            if (error_) {
-                error = *error_;
-                return {};
-            }
-        }
-
-        optional<Error> error_ = setPaintProperties(*layer, value);
-        if (error_) {
-            error = *error_;
-            return {};
-        }
-
-        return std::move(layer);
-    }
-
-private:
-    template <class LayerType, class V>
-    optional<std::unique_ptr<Layer>> convertVectorLayer(const std::string& id, const V& value, Error& error) const {
-        auto sourceValue = objectMember(value, "source");
-        if (!sourceValue) {
-            error = { "layer must have a source" };
-            return {};
-        }
-
-        optional<std::string> source = toString(*sourceValue);
-        if (!source) {
-            error = { "layer source must be a string" };
-            return {};
-        }
-
-        std::unique_ptr<LayerType> layer = std::make_unique<LayerType>(id, *source);
-
-        auto sourceLayerValue = objectMember(value, "source-layer");
-        if (sourceLayerValue) {
-            optional<std::string> sourceLayer = toString(*sourceLayerValue);
-            if (!sourceLayer) {
-                error = { "layer source-layer must be a string" };
-                return {};
-            }
-            layer->setSourceLayer(*sourceLayer);
-        }
-
-        auto filterValue = objectMember(value, "filter");
-        if (filterValue) {
-            optional<Filter> filter = convert<Filter>(*filterValue, error);
-            if (!filter) {
-                return {};
-            }
-            layer->setFilter(*filter);
-        }
-
-        return { std::move(layer) };
-    }
-
-    template <class V>
-    optional<std::unique_ptr<Layer>> convertRasterLayer(const std::string& id, const V& value, Error& error) const {
-        auto sourceValue = objectMember(value, "source");
-        if (!sourceValue) {
-            error = { "layer must have a source" };
-            return {};
-        }
-
-        optional<std::string> source = toString(*sourceValue);
-        if (!source) {
-            error = { "layer source must be a string" };
-            return {};
-        }
-
-        return { std::make_unique<RasterLayer>(id, *source) };
-    }
-
-    template <class V>
-    optional<std::unique_ptr<Layer>> convertBackgroundLayer(const std::string& id, const V&, Error&) const {
-        return { std::make_unique<BackgroundLayer>(id) };
-    }
+    optional<std::unique_ptr<Layer>> operator()(const Convertible& value, Error& error) const;
 };
 
+optional<Error> setLayoutProperty(Layer& layer, const std::string& name, const Convertible& value);
+optional<Error> setPaintProperty(Layer& layer, const std::string& name, const Convertible& value);
+optional<Error> setPaintProperties(Layer& layer, const Convertible& value);
+
 } // namespace conversion
 } // namespace style
 } // namespace mbgl

include/mbgl/style/conversion/light.hpp

@@ -2,9 +2,6 @@
 
 #include <mbgl/style/light.hpp>
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/style/conversion/position.hpp>
-#include <mbgl/style/conversion/property_value.hpp>
-#include <mbgl/style/conversion/transition_options.hpp>
 
 namespace mbgl {
 namespace style {
@@ -13,108 +10,7 @@ namespace conversion {
 template <>
 struct Converter<Light> {
 public:
-    template <class V>
-    optional<Light> operator()(const V& value, Error& error) const {
-        if (!isObject(value)) {
-            error = { "light must be an object" };
-            return {};
-        }
-
-        Light light;
-
-        const auto anchor = objectMember(value, "anchor");
-        if (anchor) {
-            optional<PropertyValue<LightAnchorType>> convertedAnchor =
-                convert<PropertyValue<LightAnchorType>>(*anchor, error);
-
-            if (convertedAnchor) {
-                light.setAnchor(*convertedAnchor);
-            } else {
-                return {};
-            }
-        }
-
-        const auto anchorTransition = objectMember(value, "anchor-transition");
-        if (anchorTransition) {
-            optional<TransitionOptions> transition =
-                convert<TransitionOptions>(*anchorTransition, error);
-            if (transition) {
-                light.setAnchorTransition(*transition);
-            } else {
-                return {};
-            }
-        }
-
-        const auto color = objectMember(value, "color");
-        if (color) {
-            optional<PropertyValue<Color>> convertedColor =
-                convert<PropertyValue<Color>>(*color, error);
-
-            if (convertedColor) {
-                light.setColor(*convertedColor);
-            } else {
-                return {};
-            }
-        }
-
-        const auto colorTransition = objectMember(value, "color-transition");
-        if (colorTransition) {
-            optional<TransitionOptions> transition =
-                convert<TransitionOptions>(*colorTransition, error);
-            if (transition) {
-                light.setColorTransition(*transition);
-            } else {
-                return {};
-            }
-        }
-
-        const auto position = objectMember(value, "position");
-        if (position) {
-            optional<PropertyValue<Position>> convertedPosition =
-                convert<PropertyValue<Position>>(*position, error);
-
-            if (convertedPosition) {
-                light.setPosition(*convertedPosition);
-            } else {
-                return {};
-            }
-        }
-
-        const auto positionTransition = objectMember(value, "position-transition");
-        if (positionTransition) {
-            optional<TransitionOptions> transition =
-                convert<TransitionOptions>(*positionTransition, error);
-            if (transition) {
-                light.setPositionTransition(*transition);
-            } else {
-                return {};
-            }
-        }
-
-        const auto intensity = objectMember(value, "intensity");
-        if (intensity) {
-            optional<PropertyValue<float>> convertedIntensity =
-                convert<PropertyValue<float>>(*intensity, error);
-
-            if (convertedIntensity) {
-                light.setIntensity(*convertedIntensity);
-            } else {
-                return {};
-            }
-        }
-
-        const auto intensityTransition = objectMember(value, "intensity-transition");
-        if (intensityTransition) {
-            optional<TransitionOptions> transition =
-                convert<TransitionOptions>(*intensityTransition, error);
-            if (transition) {
-                light.setIntensityTransition(*transition);
-            } else {
-                return {};
-            }
-        }
-        return { std::move(light) };
-    };
+    optional<Light> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/make_property_setters.hpp

@@ -1,211 +0,0 @@
-#pragma once
-
-// This file is generated. Edit make_property_setters.hpp.ejs, then run `make style-code`.
-
-#include <mbgl/style/conversion/property_setter.hpp>
-
-#include <mbgl/style/layers/fill_layer.hpp>
-#include <mbgl/style/layers/line_layer.hpp>
-#include <mbgl/style/layers/symbol_layer.hpp>
-#include <mbgl/style/layers/circle_layer.hpp>
-#include <mbgl/style/layers/fill_extrusion_layer.hpp>
-#include <mbgl/style/layers/raster_layer.hpp>
-#include <mbgl/style/layers/background_layer.hpp>
-
-#include <unordered_map>
-
-namespace mbgl {
-namespace style {
-namespace conversion {
-
-template <class V>
-auto makeLayoutPropertySetters() {
-    std::unordered_map<std::string, PropertySetter<V>> result;
-
-    result["visibility"] = &setVisibility<V>;
-
-
-    result["line-cap"] = &setProperty<V, LineLayer, PropertyValue<LineCapType>, &LineLayer::setLineCap>;
-    result["line-join"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<LineJoinType>, &LineLayer::setLineJoin>;
-    result["line-miter-limit"] = &setProperty<V, LineLayer, PropertyValue<float>, &LineLayer::setLineMiterLimit>;
-    result["line-round-limit"] = &setProperty<V, LineLayer, PropertyValue<float>, &LineLayer::setLineRoundLimit>;
-
-    result["symbol-placement"] = &setProperty<V, SymbolLayer, PropertyValue<SymbolPlacementType>, &SymbolLayer::setSymbolPlacement>;
-    result["symbol-spacing"] = &setProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setSymbolSpacing>;
-    result["symbol-avoid-edges"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setSymbolAvoidEdges>;
-    result["icon-allow-overlap"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconAllowOverlap>;
-    result["icon-ignore-placement"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconIgnorePlacement>;
-    result["icon-optional"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconOptional>;
-    result["icon-rotation-alignment"] = &setProperty<V, SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setIconRotationAlignment>;
-    result["icon-size"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconSize>;
-    result["icon-text-fit"] = &setProperty<V, SymbolLayer, PropertyValue<IconTextFitType>, &SymbolLayer::setIconTextFit>;
-    result["icon-text-fit-padding"] = &setProperty<V, SymbolLayer, PropertyValue<std::array<float, 4>>, &SymbolLayer::setIconTextFitPadding>;
-    result["icon-image"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<std::string>, &SymbolLayer::setIconImage>;
-    result["icon-rotate"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconRotate>;
-    result["icon-padding"] = &setProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setIconPadding>;
-    result["icon-keep-upright"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconKeepUpright>;
-    result["icon-offset"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<std::array<float, 2>>, &SymbolLayer::setIconOffset>;
-    result["icon-anchor"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<SymbolAnchorType>, &SymbolLayer::setIconAnchor>;
-    result["icon-pitch-alignment"] = &setProperty<V, SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setIconPitchAlignment>;
-    result["text-pitch-alignment"] = &setProperty<V, SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setTextPitchAlignment>;
-    result["text-rotation-alignment"] = &setProperty<V, SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setTextRotationAlignment>;
-    result["text-field"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<std::string>, &SymbolLayer::setTextField>;
-    result["text-font"] = &setProperty<V, SymbolLayer, PropertyValue<std::vector<std::string>>, &SymbolLayer::setTextFont>;
-    result["text-size"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextSize>;
-    result["text-max-width"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextMaxWidth>;
-    result["text-line-height"] = &setProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextLineHeight>;
-    result["text-letter-spacing"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextLetterSpacing>;
-    result["text-justify"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<TextJustifyType>, &SymbolLayer::setTextJustify>;
-    result["text-anchor"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<SymbolAnchorType>, &SymbolLayer::setTextAnchor>;
-    result["text-max-angle"] = &setProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextMaxAngle>;
-    result["text-rotate"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextRotate>;
-    result["text-padding"] = &setProperty<V, SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextPadding>;
-    result["text-keep-upright"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextKeepUpright>;
-    result["text-transform"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<TextTransformType>, &SymbolLayer::setTextTransform>;
-    result["text-offset"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<std::array<float, 2>>, &SymbolLayer::setTextOffset>;
-    result["text-allow-overlap"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextAllowOverlap>;
-    result["text-ignore-placement"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextIgnorePlacement>;
-    result["text-optional"] = &setProperty<V, SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextOptional>;
-
-
-
-
-
-    return result;
-}
-
-template <class V>
-auto makePaintPropertySetters() {
-    std::unordered_map<std::string, PropertySetter<V>> result;
-
-    result["fill-antialias"] = &setProperty<V, FillLayer, PropertyValue<bool>, &FillLayer::setFillAntialias>;
-    result["fill-antialias-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillAntialiasTransition>;
-    result["fill-opacity"] = &setProperty<V, FillLayer, DataDrivenPropertyValue<float>, &FillLayer::setFillOpacity>;
-    result["fill-opacity-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillOpacityTransition>;
-    result["fill-color"] = &setProperty<V, FillLayer, DataDrivenPropertyValue<Color>, &FillLayer::setFillColor>;
-    result["fill-color-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillColorTransition>;
-    result["fill-outline-color"] = &setProperty<V, FillLayer, DataDrivenPropertyValue<Color>, &FillLayer::setFillOutlineColor>;
-    result["fill-outline-color-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillOutlineColorTransition>;
-    result["fill-translate"] = &setProperty<V, FillLayer, PropertyValue<std::array<float, 2>>, &FillLayer::setFillTranslate>;
-    result["fill-translate-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillTranslateTransition>;
-    result["fill-translate-anchor"] = &setProperty<V, FillLayer, PropertyValue<TranslateAnchorType>, &FillLayer::setFillTranslateAnchor>;
-    result["fill-translate-anchor-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillTranslateAnchorTransition>;
-    result["fill-pattern"] = &setProperty<V, FillLayer, PropertyValue<std::string>, &FillLayer::setFillPattern>;
-    result["fill-pattern-transition"] = &setTransition<V, FillLayer, &FillLayer::setFillPatternTransition>;
-
-    result["line-opacity"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineOpacity>;
-    result["line-opacity-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineOpacityTransition>;
-    result["line-color"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<Color>, &LineLayer::setLineColor>;
-    result["line-color-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineColorTransition>;
-    result["line-translate"] = &setProperty<V, LineLayer, PropertyValue<std::array<float, 2>>, &LineLayer::setLineTranslate>;
-    result["line-translate-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineTranslateTransition>;
-    result["line-translate-anchor"] = &setProperty<V, LineLayer, PropertyValue<TranslateAnchorType>, &LineLayer::setLineTranslateAnchor>;
-    result["line-translate-anchor-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineTranslateAnchorTransition>;
-    result["line-width"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineWidth>;
-    result["line-width-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineWidthTransition>;
-    result["line-gap-width"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineGapWidth>;
-    result["line-gap-width-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineGapWidthTransition>;
-    result["line-offset"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineOffset>;
-    result["line-offset-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineOffsetTransition>;
-    result["line-blur"] = &setProperty<V, LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineBlur>;
-    result["line-blur-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineBlurTransition>;
-    result["line-dasharray"] = &setProperty<V, LineLayer, PropertyValue<std::vector<float>>, &LineLayer::setLineDasharray>;
-    result["line-dasharray-transition"] = &setTransition<V, LineLayer, &LineLayer::setLineDasharrayTransition>;
-    result["line-pattern"] = &setProperty<V, LineLayer, PropertyValue<std::string>, &LineLayer::setLinePattern>;
-    result["line-pattern-transition"] = &setTransition<V, LineLayer, &LineLayer::setLinePatternTransition>;
-
-    result["icon-opacity"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconOpacity>;
-    result["icon-opacity-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconOpacityTransition>;
-    result["icon-color"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setIconColor>;
-    result["icon-color-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconColorTransition>;
-    result["icon-halo-color"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setIconHaloColor>;
-    result["icon-halo-color-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconHaloColorTransition>;
-    result["icon-halo-width"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconHaloWidth>;
-    result["icon-halo-width-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconHaloWidthTransition>;
-    result["icon-halo-blur"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconHaloBlur>;
-    result["icon-halo-blur-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconHaloBlurTransition>;
-    result["icon-translate"] = &setProperty<V, SymbolLayer, PropertyValue<std::array<float, 2>>, &SymbolLayer::setIconTranslate>;
-    result["icon-translate-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconTranslateTransition>;
-    result["icon-translate-anchor"] = &setProperty<V, SymbolLayer, PropertyValue<TranslateAnchorType>, &SymbolLayer::setIconTranslateAnchor>;
-    result["icon-translate-anchor-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setIconTranslateAnchorTransition>;
-    result["text-opacity"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextOpacity>;
-    result["text-opacity-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextOpacityTransition>;
-    result["text-color"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setTextColor>;
-    result["text-color-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextColorTransition>;
-    result["text-halo-color"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setTextHaloColor>;
-    result["text-halo-color-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextHaloColorTransition>;
-    result["text-halo-width"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextHaloWidth>;
-    result["text-halo-width-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextHaloWidthTransition>;
-    result["text-halo-blur"] = &setProperty<V, SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextHaloBlur>;
-    result["text-halo-blur-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextHaloBlurTransition>;
-    result["text-translate"] = &setProperty<V, SymbolLayer, PropertyValue<std::array<float, 2>>, &SymbolLayer::setTextTranslate>;
-    result["text-translate-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextTranslateTransition>;
-    result["text-translate-anchor"] = &setProperty<V, SymbolLayer, PropertyValue<TranslateAnchorType>, &SymbolLayer::setTextTranslateAnchor>;
-    result["text-translate-anchor-transition"] = &setTransition<V, SymbolLayer, &SymbolLayer::setTextTranslateAnchorTransition>;
-
-    result["circle-radius"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleRadius>;
-    result["circle-radius-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleRadiusTransition>;
-    result["circle-color"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<Color>, &CircleLayer::setCircleColor>;
-    result["circle-color-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleColorTransition>;
-    result["circle-blur"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleBlur>;
-    result["circle-blur-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleBlurTransition>;
-    result["circle-opacity"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleOpacity>;
-    result["circle-opacity-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleOpacityTransition>;
-    result["circle-translate"] = &setProperty<V, CircleLayer, PropertyValue<std::array<float, 2>>, &CircleLayer::setCircleTranslate>;
-    result["circle-translate-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleTranslateTransition>;
-    result["circle-translate-anchor"] = &setProperty<V, CircleLayer, PropertyValue<TranslateAnchorType>, &CircleLayer::setCircleTranslateAnchor>;
-    result["circle-translate-anchor-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleTranslateAnchorTransition>;
-    result["circle-pitch-scale"] = &setProperty<V, CircleLayer, PropertyValue<CirclePitchScaleType>, &CircleLayer::setCirclePitchScale>;
-    result["circle-pitch-scale-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCirclePitchScaleTransition>;
-    result["circle-pitch-alignment"] = &setProperty<V, CircleLayer, PropertyValue<AlignmentType>, &CircleLayer::setCirclePitchAlignment>;
-    result["circle-pitch-alignment-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCirclePitchAlignmentTransition>;
-    result["circle-stroke-width"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleStrokeWidth>;
-    result["circle-stroke-width-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleStrokeWidthTransition>;
-    result["circle-stroke-color"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<Color>, &CircleLayer::setCircleStrokeColor>;
-    result["circle-stroke-color-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleStrokeColorTransition>;
-    result["circle-stroke-opacity"] = &setProperty<V, CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleStrokeOpacity>;
-    result["circle-stroke-opacity-transition"] = &setTransition<V, CircleLayer, &CircleLayer::setCircleStrokeOpacityTransition>;
-
-    result["fill-extrusion-opacity"] = &setProperty<V, FillExtrusionLayer, PropertyValue<float>, &FillExtrusionLayer::setFillExtrusionOpacity>;
-    result["fill-extrusion-opacity-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionOpacityTransition>;
-    result["fill-extrusion-color"] = &setProperty<V, FillExtrusionLayer, DataDrivenPropertyValue<Color>, &FillExtrusionLayer::setFillExtrusionColor>;
-    result["fill-extrusion-color-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionColorTransition>;
-    result["fill-extrusion-translate"] = &setProperty<V, FillExtrusionLayer, PropertyValue<std::array<float, 2>>, &FillExtrusionLayer::setFillExtrusionTranslate>;
-    result["fill-extrusion-translate-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionTranslateTransition>;
-    result["fill-extrusion-translate-anchor"] = &setProperty<V, FillExtrusionLayer, PropertyValue<TranslateAnchorType>, &FillExtrusionLayer::setFillExtrusionTranslateAnchor>;
-    result["fill-extrusion-translate-anchor-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionTranslateAnchorTransition>;
-    result["fill-extrusion-pattern"] = &setProperty<V, FillExtrusionLayer, PropertyValue<std::string>, &FillExtrusionLayer::setFillExtrusionPattern>;
-    result["fill-extrusion-pattern-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionPatternTransition>;
-    result["fill-extrusion-height"] = &setProperty<V, FillExtrusionLayer, DataDrivenPropertyValue<float>, &FillExtrusionLayer::setFillExtrusionHeight>;
-    result["fill-extrusion-height-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionHeightTransition>;
-    result["fill-extrusion-base"] = &setProperty<V, FillExtrusionLayer, DataDrivenPropertyValue<float>, &FillExtrusionLayer::setFillExtrusionBase>;
-    result["fill-extrusion-base-transition"] = &setTransition<V, FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionBaseTransition>;
-
-    result["raster-opacity"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterOpacity>;
-    result["raster-opacity-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterOpacityTransition>;
-    result["raster-hue-rotate"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterHueRotate>;
-    result["raster-hue-rotate-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterHueRotateTransition>;
-    result["raster-brightness-min"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterBrightnessMin>;
-    result["raster-brightness-min-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterBrightnessMinTransition>;
-    result["raster-brightness-max"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterBrightnessMax>;
-    result["raster-brightness-max-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterBrightnessMaxTransition>;
-    result["raster-saturation"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterSaturation>;
-    result["raster-saturation-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterSaturationTransition>;
-    result["raster-contrast"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterContrast>;
-    result["raster-contrast-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterContrastTransition>;
-    result["raster-fade-duration"] = &setProperty<V, RasterLayer, PropertyValue<float>, &RasterLayer::setRasterFadeDuration>;
-    result["raster-fade-duration-transition"] = &setTransition<V, RasterLayer, &RasterLayer::setRasterFadeDurationTransition>;
-
-    result["background-color"] = &setProperty<V, BackgroundLayer, PropertyValue<Color>, &BackgroundLayer::setBackgroundColor>;
-    result["background-color-transition"] = &setTransition<V, BackgroundLayer, &BackgroundLayer::setBackgroundColorTransition>;
-    result["background-pattern"] = &setProperty<V, BackgroundLayer, PropertyValue<std::string>, &BackgroundLayer::setBackgroundPattern>;
-    result["background-pattern-transition"] = &setTransition<V, BackgroundLayer, &BackgroundLayer::setBackgroundPatternTransition>;
-    result["background-opacity"] = &setProperty<V, BackgroundLayer, PropertyValue<float>, &BackgroundLayer::setBackgroundOpacity>;
-    result["background-opacity-transition"] = &setTransition<V, BackgroundLayer, &BackgroundLayer::setBackgroundOpacityTransition>;
-
-    return result;
-}
-
-} // namespace conversion
-} // namespace style
-} // namespace mbgl

include/mbgl/style/conversion/make_property_setters.hpp.ejs

@@ -1,48 +0,0 @@
-#pragma once
-
-// This file is generated. Edit make_property_setters.hpp.ejs, then run `make style-code`.
-
-#include <mbgl/style/conversion/property_setter.hpp>
-
-<% for (const layer of locals.layers) { -%>
-#include <mbgl/style/layers/<%- layer.type.replace('-', '_') %>_layer.hpp>
-<% } -%>
-
-#include <unordered_map>
-
-namespace mbgl {
-namespace style {
-namespace conversion {
-
-template <class V>
-auto makeLayoutPropertySetters() {
-    std::unordered_map<std::string, PropertySetter<V>> result;
-
-    result["visibility"] = &setVisibility<V>;
-
-<% for (const layer of locals.layers) { -%>
-<% for (const property of layer.layoutProperties) { -%>
-    result["<%- property.name %>"] = &setProperty<V, <%- camelize(layer.type) %>Layer, <%- propertyValueType(property) %>, &<%- camelize(layer.type) %>Layer::set<%- camelize(property.name) %>>;
-<% } -%>
-
-<% } -%>
-    return result;
-}
-
-template <class V>
-auto makePaintPropertySetters() {
-    std::unordered_map<std::string, PropertySetter<V>> result;
-
-<% for (const layer of locals.layers) { -%>
-<% for (const property of layer.paintProperties) { -%>
-    result["<%- property.name %>"] = &setProperty<V, <%- camelize(layer.type) %>Layer, <%- propertyValueType(property) %>, &<%- camelize(layer.type) %>Layer::set<%- camelize(property.name) %>>;
-    result["<%- property.name %>-transition"] = &setTransition<V, <%- camelize(layer.type) %>Layer, &<%- camelize(layer.type) %>Layer::set<%- camelize(property.name) %>Transition>;
-<% } -%>
-
-<% } -%>
-    return result;
-}
-
-} // namespace conversion
-} // namespace style
-} // namespace mbgl

include/mbgl/style/conversion/position.hpp

@@ -2,9 +2,6 @@
 
 #include <mbgl/style/conversion.hpp>
 #include <mbgl/style/position.hpp>
-#include <mbgl/util/optional.hpp>
-
-#include <array>
 
 namespace mbgl {
 namespace style {
@@ -12,16 +9,7 @@ namespace conversion {
 
 template <>
 struct Converter<Position> {
-    template <class V>
-    optional<Position> operator()(const V& value, Error& error) const {
-        optional<std::array<float, 3>> spherical = convert<std::array<float, 3>>(value, error);
-
-        if (!spherical) {
-            return {};
-        }
-
-        return Position(*spherical);
-    }
+    optional<Position> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/property_value.hpp

@@ -11,8 +11,7 @@ namespace conversion {
 
 template <class T>
 struct Converter<PropertyValue<T>> {
-    template <class V>
-    optional<PropertyValue<T>> operator()(const V& value, Error& error) const {
+    optional<PropertyValue<T>> operator()(const Convertible& value, Error& error) const {
         if (isUndefined(value)) {
             return PropertyValue<T>();
         } else if (isObject(value)) {

include/mbgl/style/conversion/source.hpp

@@ -1,16 +1,9 @@
 #pragma once
 
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/style/conversion/coordinate.hpp>
-#include <mbgl/style/conversion/geojson.hpp>
-#include <mbgl/style/conversion/geojson_options.hpp>
-#include <mbgl/style/conversion/tileset.hpp>
 #include <mbgl/style/source.hpp>
-#include <mbgl/style/sources/geojson_source.hpp>
-#include <mbgl/style/sources/raster_source.hpp>
-#include <mbgl/style/sources/vector_source.hpp>
-#include <mbgl/style/sources/image_source.hpp>
-#include <mbgl/util/geo.hpp>
+
+#include <memory>
 
 namespace mbgl {
 namespace style {
@@ -19,170 +12,7 @@ namespace conversion {
 template <>
 struct Converter<std::unique_ptr<Source>> {
 public:
-    
-    template <class V>
-    optional<std::unique_ptr<Source>> operator()(const V& value, Error& error, const std::string& id) const {
-        if (!isObject(value)) {
-            error = { "source must be an object" };
-            return {};
-        }
-
-        auto typeValue = objectMember(value, "type");
-        if (!typeValue) {
-            error = { "source must have a type" };
-            return {};
-        }
-
-        optional<std::string> type = toString(*typeValue);
-        if (!type) {
-            error = { "source type must be a string" };
-            return {};
-        }
-
-        if (*type == "raster") {
-            return convertRasterSource(id, value, error);
-        } else if (*type == "vector") {
-            return convertVectorSource(id, value, error);
-        } else if (*type == "geojson") {
-            return convertGeoJSONSource(id, value, error);
-        } else if (*type == "image") {
-            return convertImageSource(id, value, error);
-        } else {
-            error = { "invalid source type" };
-            return {};
-        }
-    }
-
-private:
-    // A tile source can either specify a URL to TileJSON, or inline TileJSON.
-    template <class V>
-    optional<variant<std::string, Tileset>> convertURLOrTileset(const V& value, Error& error) const {
-        auto urlVal = objectMember(value, "url");
-        if (!urlVal) {
-            optional<Tileset> tileset = convert<Tileset>(value, error);
-            if (!tileset) {
-                return {};
-            }
-            return { *tileset };
-        }
-
-        optional<std::string> url = toString(*urlVal);
-        if (!url) {
-            error = { "source url must be a string" };
-            return {};
-        }
-
-        return { *url };
-    }
-
-    template <class V>
-    optional<std::unique_ptr<Source>> convertRasterSource(const std::string& id,
-                                                          const V& value,
-                                                          Error& error) const {
-        optional<variant<std::string, Tileset>> urlOrTileset = convertURLOrTileset(value, error);
-        if (!urlOrTileset) {
-            return {};
-        }
-
-        uint16_t tileSize = util::tileSize;
-        auto tileSizeValue = objectMember(value, "tileSize");
-        if (tileSizeValue) {
-            optional<float> size = toNumber(*tileSizeValue);
-            if (!size || *size < 0 || *size > std::numeric_limits<uint16_t>::max()) {
-                error = { "invalid tileSize" };
-                return {};
-            }
-            tileSize = *size;
-        }
-
-        return { std::make_unique<RasterSource>(id, std::move(*urlOrTileset), tileSize) };
-    }
-
-    template <class V>
-    optional<std::unique_ptr<Source>> convertVectorSource(const std::string& id,
-                                                          const V& value,
-                                                          Error& error) const {
-        optional<variant<std::string, Tileset>> urlOrTileset = convertURLOrTileset(value, error);
-        if (!urlOrTileset) {
-            return {};
-        }
-
-        return { std::make_unique<VectorSource>(id, std::move(*urlOrTileset)) };
-    }
-
-    template <class V>
-    optional<std::unique_ptr<Source>> convertGeoJSONSource(const std::string& id,
-                                                           const V& value,
-                                                           Error& error) const {
-        auto dataValue = objectMember(value, "data");
-        if (!dataValue) {
-            error = { "GeoJSON source must have a data value" };
-            return {};
-        }
-
-        optional<GeoJSONOptions> options = convert<GeoJSONOptions>(value, error);
-        if (!options) {
-            return {};
-        }
-
-        auto result = std::make_unique<GeoJSONSource>(id, *options);
-
-        if (isObject(*dataValue)) {
-            optional<GeoJSON> geoJSON = convert<GeoJSON>(*dataValue, error);
-            if (!geoJSON) {
-                return {};
-            }
-            result->setGeoJSON(std::move(*geoJSON));
-        } else if (toString(*dataValue)) {
-            result->setURL(*toString(*dataValue));
-        } else {
-            error = { "GeoJSON data must be a URL or an object" };
-            return {};
-        }
-
-        return { std::move(result) };
-    }
-    
-    template <class V>
-    optional<std::unique_ptr<Source>> convertImageSource(const std::string& id,
-                                                        const V& value,
-                                                        Error& error) const {
-        auto urlValue = objectMember(value, "url");
-        if (!urlValue) {
-            error = { "Image source must have a url value" };
-            return {};
-        }
-        
-        auto urlString = toString(*urlValue);
-        if (!urlString) {
-            error = { "Image url must be a URL string" };
-            return {};
-        }
-        
-        auto coordinatesValue = objectMember(value, "coordinates");
-        if (!coordinatesValue) {
-            error = { "Image source must have a coordinates values" };
-            return {};
-        }
-        
-        if (!isArray(*coordinatesValue) || arrayLength(*coordinatesValue) != 4) {
-            error = { "Image coordinates must be an array of four longitude latitude pairs" };
-            return {};
-        }
-        
-        std::array<LatLng, 4> coordinates;
-        for (std::size_t i=0; i < 4; i++) {
-            auto latLng = conversion::convert<LatLng>(arrayMember(*coordinatesValue,i), error);
-            if (!latLng) {
-                return {};
-            }
-            coordinates[i] = *latLng;
-        }
-        auto result = std::make_unique<ImageSource>(id, coordinates);
-        result->setURL(*urlString);
-
-        return { std::move(result) };
-    }
+    optional<std::unique_ptr<Source>> operator()(const Convertible& value, Error& error, const std::string& id) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/tileset.hpp

@@ -10,70 +10,7 @@ namespace conversion {
 template <>
 struct Converter<Tileset> {
 public:
-    template <class V>
-    optional<Tileset> operator()(const V& value, Error& error) const {
-        Tileset result;
-
-        auto tiles = objectMember(value, "tiles");
-        if (!tiles) {
-            error = { "source must have tiles" };
-            return {};
-        }
-
-        if (!isArray(*tiles)) {
-            error = { "source tiles must be an array" };
-            return {};
-        }
-
-        for (std::size_t i = 0; i < arrayLength(*tiles); i++) {
-            optional<std::string> urlTemplate = toString(arrayMember(*tiles, i));
-            if (!urlTemplate) {
-                error = { "source tiles member must be a string" };
-                return {};
-            }
-            result.tiles.push_back(std::move(*urlTemplate));
-        }
-
-        auto schemeValue = objectMember(value, "scheme");
-        if (schemeValue) {
-            optional<std::string> scheme = toString(*schemeValue);
-            if (scheme && *scheme == "tms") {
-                result.scheme = Tileset::Scheme::TMS;
-            }
-        }
-
-        auto minzoomValue = objectMember(value, "minzoom");
-        if (minzoomValue) {
-            optional<float> minzoom = toNumber(*minzoomValue);
-            if (!minzoom || *minzoom < 0 || *minzoom > std::numeric_limits<uint8_t>::max()) {
-                error = { "invalid minzoom" };
-                return {};
-            }
-            result.zoomRange.min = *minzoom;
-        }
-
-        auto maxzoomValue = objectMember(value, "maxzoom");
-        if (maxzoomValue) {
-            optional<float> maxzoom = toNumber(*maxzoomValue);
-            if (!maxzoom || *maxzoom < 0 || *maxzoom > std::numeric_limits<uint8_t>::max()) {
-                error = { "invalid maxzoom" };
-                return {};
-            }
-            result.zoomRange.max = *maxzoom;
-        }
-
-        auto attributionValue = objectMember(value, "attribution");
-        if (attributionValue) {
-            optional<std::string> attribution = toString(*attributionValue);
-            if (!attribution) {
-                error = { "source attribution must be a string" };
-                return {};
-            }
-            result.attribution = std::move(*attribution);
-        }
-
-        return result;
-    }
+    optional<Tileset> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/style/conversion/transition_options.hpp

@@ -10,37 +10,7 @@ namespace conversion {
 template <>
 struct Converter<TransitionOptions> {
 public:
-    template <class V>
-    optional<TransitionOptions> operator()(const V& value, Error& error) const {
-        if (!isObject(value)) {
-            error = { "transition must be an object" };
-            return {};
-        }
-
-        TransitionOptions result;
-
-        auto duration = objectMember(value, "duration");
-        if (duration) {
-            auto number = toNumber(*duration);
-            if (!number) {
-                error = { "duration must be a number" };
-                return {};
-            }
-            result.duration = { std::chrono::milliseconds(int64_t(*number)) };
-        }
-
-        auto delay = objectMember(value, "delay");
-        if (delay) {
-            auto number = toNumber(*delay);
-            if (!number) {
-                error = { "delay must be a number" };
-                return {};
-            }
-            result.delay = { std::chrono::milliseconds(int64_t(*number)) };
-        }
-
-        return result;
-    }
+    optional<TransitionOptions> operator()(const Convertible& value, Error& error) const;
 };
 
 } // namespace conversion

include/mbgl/util/tileset.hpp

@@ -3,6 +3,7 @@
 #include <mbgl/util/range.hpp>
 #include <mbgl/util/constants.hpp>
 
+#include <tuple>
 #include <vector>
 #include <string>
 #include <cstdint>

platform/android/config.cmake

@@ -146,7 +146,6 @@ add_library(mbgl-android STATIC
 
     # Style conversion Java -> C++
     platform/android/src/style/android_conversion.hpp
-    platform/android/src/style/conversion/geojson.hpp
     platform/android/src/style/value.cpp
     platform/android/src/style/value.hpp
     platform/android/src/style/conversion/url_or_tileset.hpp

platform/android/src/style/android_conversion.hpp

@@ -4,8 +4,9 @@
 
 #include <mbgl/util/feature.hpp>
 #include <mbgl/util/logging.hpp>
-#include <mbgl/style/conversion.hpp>
 #include <mbgl/util/optional.hpp>
+#include <mbgl/style/conversion.hpp>
+#include <mbgl/style/conversion/geojson.hpp>
 
 #include <jni/jni.hpp>
 
@@ -13,89 +14,105 @@ namespace mbgl {
 namespace style {
 namespace conversion {
 
-inline bool isUndefined(const mbgl::android::Value& value) {
-    return value.isNull();
-}
+template <>
+class ConversionTraits<mbgl::android::Value> {
+public:
+    static bool isUndefined(const mbgl::android::Value& value) {
+        return value.isNull();
+    }
 
-inline bool isArray(const mbgl::android::Value& value) {
-    return value.isArray();
-}
+    static bool isArray(const mbgl::android::Value& value) {
+        return value.isArray();
+    }
 
-inline bool isObject(const mbgl::android::Value& value) {
-    return value.isObject();
-}
+    static bool isObject(const mbgl::android::Value& value) {
+        return value.isObject();
+    }
 
-inline std::size_t arrayLength(const mbgl::android::Value& value) {
-    return value.getLength();;
-}
+    static std::size_t arrayLength(const mbgl::android::Value& value) {
+        return value.getLength();;
+    }
 
-inline mbgl::android::Value arrayMember(const mbgl::android::Value& value, std::size_t i) {
-    return value.get(i);
-}
+    static mbgl::android::Value arrayMember(const mbgl::android::Value& value, std::size_t i) {
+        return value.get(i);
+    }
 
-inline optional<mbgl::android::Value> objectMember(const mbgl::android::Value& value, const char* key) {
-    mbgl::android::Value member = value.get(key);
+    static optional<mbgl::android::Value> objectMember(const mbgl::android::Value& value, const char* key) {
+        mbgl::android::Value member = value.get(key);
+        if (!member.isNull()) {
+            return member;
+        } else {
+            return {};
+        }
+    }
 
-    if (!member.isNull()) {
-        return member;
-    } else {
+    template <class Fn>
+    static optional<Error> eachMember(const mbgl::android::Value&, Fn&&) {
+        // TODO
+        mbgl::Log::Warning(mbgl::Event::Android, "eachMember not implemented");
         return {};
     }
-}
 
-template <class Fn>
-optional<Error> eachMember(const mbgl::android::Value&, Fn&&) {
-    // TODO
-    mbgl::Log::Warning(mbgl::Event::Android, "eachMember not implemented");
-    return {};
-}
-
-inline optional<bool> toBool(const mbgl::android::Value& value) {
-    if (value.isBool()) {
-        return value.toBool();
-    } else {
-        return {};
+    static optional<bool> toBool(const mbgl::android::Value& value) {
+        if (value.isBool()) {
+            return value.toBool();
+        } else {
+            return {};
+        }
     }
-}
 
-inline optional<float> toNumber(const mbgl::android::Value& value) {
-    if (value.isNumber()) {
-        auto num = value.toFloat();
-        return num;
-    } else {
-        return {};
+    static optional<float> toNumber(const mbgl::android::Value& value) {
+        if (value.isNumber()) {
+            auto num = value.toFloat();
+            return num;
+        } else {
+            return {};
+        }
     }
-}
 
-inline optional<double> toDouble(const mbgl::android::Value& value) {
-    if (value.isNumber()) {
-        return value.toDouble();
-    } else {
-        return {};
+    static optional<double> toDouble(const mbgl::android::Value& value) {
+        if (value.isNumber()) {
+            return value.toDouble();
+        } else {
+            return {};
+        }
     }
-}
 
-inline optional<std::string> toString(const mbgl::android::Value& value) {
-    if (value.isString()) {
-        return value.toString();
-    } else {
-        return {};
+    static optional<std::string> toString(const mbgl::android::Value& value) {
+        if (value.isString()) {
+            return value.toString();
+        } else {
+            return {};
+        }
     }
-}
 
-inline optional<Value> toValue(const mbgl::android::Value& value) {
-    if (value.isNull()) {
-        return {};
-    } else if (value.isBool()) {
-        return { value.toBool() };
-    } else if (value.isString()) {
-        return { value.toString() };
-    } else if (value.isNumber()) {
-        auto doubleVal = value.toDouble();
-        return { doubleVal - (int) doubleVal > 0.0 ? doubleVal : value.toLong() };
-    } else {
-        return {};
+    static optional<Value> toValue(const mbgl::android::Value& value) {
+        if (value.isNull()) {
+            return {};
+        } else if (value.isBool()) {
+            return { value.toBool() };
+        } else if (value.isString()) {
+            return { value.toString() };
+        } else if (value.isNumber()) {
+            auto doubleVal = value.toDouble();
+            return { doubleVal - (int) doubleVal > 0.0 ? doubleVal : value.toLong() };
+        } else {
+            return {};
+        }
     }
+
+    static optional<GeoJSON> toGeoJSON(const mbgl::android::Value &value, Error &error) {
+        if (value.isNull() || !value.isString()) {
+            error = { "no json data found" };
+            return {};
+        }
+        return parseGeoJSON(value.toString(), error);
+    }
+};
+
+template <class T, class...Args>
+optional<T> convert(mbgl::android::Value&& value, Error& error, Args&&...args) {
+    return convert<T>(Convertible(std::move(value)), error, std::forward<Args>(args)...);
 }
 
 } // namespace conversion

platform/android/src/style/conversion/filter.hpp

@@ -16,9 +16,8 @@ namespace conversion {
 inline optional<mbgl::style::Filter> toFilter(jni::JNIEnv& env, jni::Array<jni::Object<>> jfilter) {
     mbgl::optional<mbgl::style::Filter> filter;
     if (jfilter) {
-      Value filterValue(env, jfilter);
       mbgl::style::conversion::Error error;
-      auto converted = mbgl::style::conversion::convert<mbgl::style::Filter>(filterValue, error);
+      auto converted = mbgl::style::conversion::convert<mbgl::style::Filter>(Value(env, jfilter), error);
       if (!converted) {
           mbgl::Log::Error(mbgl::Event::JNI, "Error converting filter: " + error.message);
       }

platform/android/src/style/conversion/geojson.hpp

@@ -1,24 +0,0 @@
-#pragma once
-
-#include <mapbox/geojson.hpp>
-#include <mbgl/style/conversion.hpp>
-#include <mbgl/style/conversion/geojson.hpp>
-#include <jni/jni.hpp>
-
-namespace mbgl {
-namespace style {
-namespace conversion {
-
-template <>
-optional<GeoJSON> Converter<GeoJSON>::operator()(const mbgl::android::Value& value, Error& error) const {
-    if(value.isNull() || !value.isString()) {
-        error = { "no json data found" };
-        return {};
-    }
-
-    return convert<GeoJSON>(value.toString(), error);
-}
-
-} // namespace conversion
-} // namespace style
-} // namespace mbgl

platform/android/src/style/conversion/url_or_tileset.hpp

@@ -17,18 +17,19 @@ namespace android {
 // This conversion is expected not to fail because it's used only in contexts where
 // the value was originally a String or TileSet object on the Java side. If it fails
 // to convert, it's a bug in our serialization or Java-side static typing.
-inline variant<std::string, Tileset> convertURLOrTileset(const Value& value) {
+inline variant<std::string, Tileset> convertURLOrTileset(mbgl::android::Value&& value) {
     using namespace mbgl::style::conversion;
 
-    if (isObject(value)) {
+    const Convertible convertible(std::move(value));
+    if (isObject(convertible)) {
         Error error;
-        optional<Tileset> tileset = convert<Tileset>(value, error);
+        optional<Tileset> tileset = convert<Tileset>(convertible, error);
         if (!tileset) {
             throw std::logic_error(error.message);
         }
         return { *tileset };
     } else {
-        return { *toString(value) };
+        return { *toString(convertible) };
     }
 }
 

platform/android/src/style/layers/layer.cpp

@@ -4,11 +4,20 @@
 #include <jni/jni.hpp>
 
 #include <mbgl/style/style.hpp>
+#include <mbgl/style/filter.hpp>
 #include <mbgl/style/transition_options.hpp>
+#include <mbgl/style/layers/background_layer.hpp>
+#include <mbgl/style/layers/circle_layer.hpp>
+#include <mbgl/style/layers/fill_layer.hpp>
+#include <mbgl/style/layers/fill_extrusion_layer.hpp>
+#include <mbgl/style/layers/line_layer.hpp>
+#include <mbgl/style/layers/raster_layer.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
 #include <mbgl/util/logging.hpp>
 
 // Java -> C++ conversion
 #include <mbgl/style/conversion.hpp>
+#include <mbgl/style/conversion/filter.hpp>
 #include <mbgl/style/conversion/layer.hpp>
 #include <mbgl/style/conversion/source.hpp>
 
@@ -78,10 +87,8 @@ namespace android {
     }
 
     void Layer::setLayoutProperty(jni::JNIEnv& env, jni::String jname, jni::Object<> jvalue) {
-        Value value(env, jvalue);
-
         // Convert and set property
-        optional<mbgl::style::conversion::Error> error = mbgl::style::conversion::setLayoutProperty(layer, jni::Make<std::string>(env, jname), value);
+        optional<mbgl::style::conversion::Error> error = mbgl::style::conversion::setLayoutProperty(layer, jni::Make<std::string>(env, jname), Value(env, jvalue));
         if (error) {
             mbgl::Log::Error(mbgl::Event::JNI, "Error setting property: " + jni::Make<std::string>(env, jname) + " " + error->message);
             return;
@@ -89,10 +96,8 @@ namespace android {
     }
 
     void Layer::setPaintProperty(jni::JNIEnv& env, jni::String jname, jni::Object<> jvalue) {
-        Value value(env, jvalue);
-
         // Convert and set property
-        optional<mbgl::style::conversion::Error> error = mbgl::style::conversion::setPaintProperty(layer, jni::Make<std::string>(env, jname), value);
+        optional<mbgl::style::conversion::Error> error = mbgl::style::conversion::setPaintProperty(layer, jni::Make<std::string>(env, jname), Value(env, jvalue));
         if (error) {
             mbgl::Log::Error(mbgl::Event::JNI, "Error setting property: " + jni::Make<std::string>(env, jname) + " " + error->message);
             return;
@@ -116,10 +121,8 @@ namespace android {
         using namespace mbgl::style;
         using namespace mbgl::style::conversion;
 
-        Value wrapped(env, jfilter);
-
         Error error;
-        optional<Filter> converted = convert<Filter>(wrapped, error);
+        optional<Filter> converted = convert<Filter>(Value(env, jfilter), error);
         if (!converted) {
             mbgl::Log::Error(mbgl::Event::JNI, "Error setting filter: " + error.message);
             return;

platform/android/src/style/sources/geojson_source.cpp

@@ -5,15 +5,15 @@
 // Java -> C++ conversion
 #include "../android_conversion.hpp"
 #include "../conversion/filter.hpp"
-#include "../conversion/geojson.hpp"
+#include <mbgl/style/conversion.hpp>
+#include <mbgl/style/conversion/geojson.hpp>
+#include <mbgl/style/conversion/geojson_options.hpp>
 
 // C++ -> Java conversion
 #include "../../conversion/conversion.hpp"
 #include "../../conversion/collection.hpp"
 #include "../../geojson/conversion/feature.hpp"
 #include "../conversion/url_or_tileset.hpp"
-#include <mbgl/style/conversion.hpp>
-#include <mbgl/style/conversion/geojson_options.hpp>
 
 #include <string>
 
@@ -29,7 +29,7 @@ namespace android {
             return style::GeoJSONOptions();
         }
         Error error;
-        optional<style::GeoJSONOptions> result = convert<style::GeoJSONOptions>(Value(env, options), error);
+        optional<style::GeoJSONOptions> result = convert<style::GeoJSONOptions>(mbgl::android::Value(env, options), error);
         if (!result) {
             throw std::logic_error(error.message);
         }
@@ -54,7 +54,7 @@ namespace android {
 
         // Convert the jni object
         Error error;
-        optional<GeoJSON> converted = convert<GeoJSON>(Value(env, json), error);
+        optional<GeoJSON> converted = convert<GeoJSON>(mbgl::android::Value(env, json), error);
         if(!converted) {
             mbgl::Log::Error(mbgl::Event::JNI, "Error setting geo json: " + error.message);
             return;

platform/android/src/style/value.cpp

@@ -24,8 +24,6 @@ namespace android {
 
     Value::Value(jni::JNIEnv& _env, jni::jobject* _value) : env(_env), value(_value, ObjectDeleter(env)) {}
 
-    Value::~Value() = default;
-
     bool Value::isNull() const {
         return value == nullptr;
     }

platform/android/src/style/value.hpp

@@ -9,9 +9,13 @@ namespace android {
 
 class Value {
 public:
-
     Value(jni::JNIEnv&, jni::jobject*);
-    virtual ~Value();
+
+    Value(Value&&)                 = default;
+    Value& operator=(Value&&)      = default;
+
+    Value(const Value&)            = delete;
+    Value& operator=(const Value&) = delete;
 
     bool isNull() const;
     bool isArray() const;

platform/darwin/src/MGLConversion.h

@@ -1,9 +1,4 @@
-#import <Foundation/Foundation.h>
-
-#include <mbgl/util/logging.hpp>
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/util/feature.hpp>
-#include <mbgl/util/optional.hpp>
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -11,128 +6,147 @@ namespace mbgl {
 namespace style {
 namespace conversion {
 
-/**
- A minimal wrapper class conforming to the requirements for `objectMember(v, name)` (see mbgl/style/conversion.hpp)
- This is necessary because using `NSObject*` as the value type in `optional<NSObject*>` causes problems for the ARC,
- due to things like `optional(const value_type& __v)`
- */
-class OptionalNSObjectValue {
+// A wrapper class for `id`, so as not to confuse ARC.
+class Holder {
 public:
-    OptionalNSObjectValue(NSObject * _Nullable _value) : value(_value) {}
-    
-    explicit operator bool() const {
-        return value;
-    }
-    
-    NSObject * _Nullable operator*() {
-        NSCAssert(this, @"Expected non-null value.");
-        return value;
-    }
-private:
-    NSObject * _Nullable value;
+    Holder(const id v) : value(v) {}
+    const id value;
 };
 
-inline bool isUndefined(const id value) {
-    return !value || value == [NSNull null];
-}
-
-inline bool isArray(const id value) {
-    return [value isKindOfClass:[NSArray class]];
-}
-
-inline bool isObject(const id value) {
-    return [value isKindOfClass:[NSDictionary class]];
-}
-
-inline std::size_t arrayLength(const id value) {
-    NSCAssert([value isKindOfClass:[NSArray class]], @"Value must be an NSArray for getLength().");
-    NSArray *array = value;
-    auto length = [array count];
-    NSCAssert(length <= std::numeric_limits<size_t>::max(), @"Array length out of bounds.");
-    return length;
-}
-
-inline NSObject *arrayMember(const id value, std::size_t i) {
-    NSCAssert([value isKindOfClass:[NSArray class]], @"Value must be an NSArray for get(int).");
-    NSCAssert(i < NSUIntegerMax, @"Index must be less than NSUIntegerMax");
-    return [value objectAtIndex: i];
-}
-
-inline OptionalNSObjectValue objectMember(const id value, const char *key) {
-    NSCAssert([value isKindOfClass:[NSDictionary class]], @"Value must be an NSDictionary for get(string).");
-    NSObject *member = [value objectForKey: @(key)];
-    if (member && member != [NSNull null]) {
-        return { member };
-    } else {
-        return { nullptr };
+template <>
+class ConversionTraits<Holder> {
+public:
+    static bool isUndefined(const Holder& holder) {
+        const id value = holder.value;
+        return !value || value == [NSNull null];
     }
-}
 
-// Not implemented (unneeded for MGLStyleFunction conversion):
-// optional<Error> eachMember(const NSObject*, Fn&&)
+    static bool isArray(const Holder& holder) {
+        const id value = holder.value;
+        return [value isKindOfClass:[NSArray class]];
+    }
 
-inline bool _isBool(const id value) {
-    if (![value isKindOfClass:[NSNumber class]]) return false;
-    // char: 32-bit boolean
-    // BOOL: 64-bit boolean
-    NSNumber *number = value;
-    return ((strcmp([number objCType], @encode(char)) == 0) ||
-            (strcmp([number objCType], @encode(BOOL)) == 0));
-}
-    
-inline bool _isNumber(const id value) {
-    return [value isKindOfClass:[NSNumber class]] && !_isBool(value);
-}
-    
-inline bool _isString(const id value) {
-    return [value isKindOfClass:[NSString class]];
-}
+    static bool isObject(const Holder& holder) {
+        const id value = holder.value;
+        return [value isKindOfClass:[NSDictionary class]];
+    }
 
-inline optional<bool> toBool(const id value) {
-    if (_isBool(value)) {
-        return ((NSNumber *)value).boolValue;
-    } else {
+    static std::size_t arrayLength(const Holder& holder) {
+        const id value = holder.value;
+        NSCAssert([value isKindOfClass:[NSArray class]], @"Value must be an NSArray for getLength().");
+        NSArray *array = value;
+        auto length = [array count];
+        NSCAssert(length <= std::numeric_limits<size_t>::max(), @"Array length out of bounds.");
+        return length;
+    }
+
+    static Holder arrayMember(const Holder& holder, std::size_t i) {
+        const id value = holder.value;
+        NSCAssert([value isKindOfClass:[NSArray class]], @"Value must be an NSArray for get(int).");
+        NSCAssert(i < NSUIntegerMax, @"Index must be less than NSUIntegerMax");
+        return {[value objectAtIndex: i]};
+    }
+
+    static optional<Holder> objectMember(const Holder& holder, const char *key) {
+        const id value = holder.value;
+        NSCAssert([value isKindOfClass:[NSDictionary class]], @"Value must be an NSDictionary for get(string).");
+        NSObject *member = [value objectForKey: @(key)];
+        if (member && member != [NSNull null]) {
+            return {member};
+        } else {
+            return {};
+        }
+    }
+
+// Compiler is wrong about `Fn` parameter missing a nullability specifier.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnullability-completeness"
+    template <class Fn>
+    static optional<Error> eachMember(const Holder&, Fn&&) {
+#pragma clang diagnostic pop
+        // Not implemented (unneeded for MGLStyleFunction conversion).
+        NSCAssert(NO, @"eachMember not implemented");
         return {};
     }
-}
 
-inline optional<float> toNumber(const id value) {
-    if (_isNumber(value)) {
-        return ((NSNumber *)value).floatValue;
-    } else {
+    static optional<bool> toBool(const Holder& holder) {
+        const id value = holder.value;
+        if (_isBool(value)) {
+            return ((NSNumber *)value).boolValue;
+        } else {
+            return {};
+        }
+    }
+
+    static optional<float> toNumber(const Holder& holder) {
+        const id value = holder.value;
+        if (_isNumber(value)) {
+            return ((NSNumber *)value).floatValue;
+        } else {
+            return {};
+        }
+    }
+
+    static optional<double> toDouble(const Holder& holder) {
+        const id value = holder.value;
+        if (_isNumber(value)) {
+            return ((NSNumber *)value).doubleValue;
+        } else {
+            return {};
+        }
+    }
+
+    static optional<std::string> toString(const Holder& holder) {
+        const id value = holder.value;
+        if (_isString(value)) {
+            return std::string(static_cast<const char *>([value UTF8String]));
+        } else {
+            return {};
+        }
+    }
+
+    static optional<mbgl::Value> toValue(const Holder& holder) {
+        const id value = holder.value;
+        if (isUndefined(value)) {
+            return {};
+        } else if (_isBool(value)) {
+            return { *toBool(holder) };
+        } else if ( _isString(value)) {
+            return { *toString(holder) };
+        } else if (_isNumber(value)) {
+            // Need to cast to a double here as the float is otherwise considered a bool...
+           return { static_cast<double>(*toNumber(holder)) };
+        } else {
+            return {};
+        }
+    }
+
+    static optional<GeoJSON> toGeoJSON(const Holder& holder, Error& error) {
+        error = { "toGeoJSON not implemented" };
         return {};
     }
-}
 
-inline optional<double> toDouble(const id value) {
-    if (_isNumber(value)) {
-        return ((NSNumber *)value).doubleValue;
-    } else {
-        return {};
+private:
+    static bool _isBool(const id value) {
+        if (![value isKindOfClass:[NSNumber class]]) return false;
+        // char: 32-bit boolean
+        // BOOL: 64-bit boolean
+        NSNumber *number = value;
+        return ((strcmp([number objCType], @encode(char)) == 0) ||
+                (strcmp([number objCType], @encode(BOOL)) == 0));
     }
-}
 
-inline optional<std::string> toString(const id value) {
-    if (_isString(value)) {
-        return std::string(static_cast<const char *>([value UTF8String]));
-    } else {
-        return {};
+    static bool _isNumber(const id value) {
+        return [value isKindOfClass:[NSNumber class]] && !_isBool(value);
     }
-}
 
-inline optional<mbgl::Value> toValue(const id value) {
-    if (isUndefined(value)) {
-        return {};
-    } else if (_isBool(value)) {
-        return { *toBool(value) };
-    } else if ( _isString(value)) {
-        return { *toString(value) };
-    } else if (_isNumber(value)) {
-        // Need to cast to a double here as the float is otherwise considered a bool...
-       return { static_cast<double>(*toNumber(value)) };
-    } else {
-        return {};
+    static bool _isString(const id value) {
+        return [value isKindOfClass:[NSString class]];
     }
+};
+
+inline Convertible makeConvertible(const id value) {
+    return Convertible(Holder(value));
 }
 
 } // namespace conversion
@@ -140,4 +154,3 @@ inline optional<mbgl::Value> toValue(const id value) {
 } // namespace mbgl
 
 NS_ASSUME_NONNULL_END
-

platform/darwin/src/MGLStyleValue_Private.h

@@ -124,9 +124,9 @@ public:
         if ([value isKindOfClass:[MGLConstantStyleValue class]]) {
             return toMBGLConstantValue((MGLConstantStyleValue<ObjCType> *)value);
         } else if ([value isKindOfClass:[MGLStyleFunction class]]) {
-            auto rawValue = toRawStyleSpecValue((MGLStyleFunction<ObjCType> *) value);
             mbgl::style::conversion::Error error;
-            auto result = mbgl::style::conversion::convert<mbgl::style::DataDrivenPropertyValue<MBGLType>>(rawValue, error);
+            auto result = mbgl::style::conversion::convert<mbgl::style::DataDrivenPropertyValue<MBGLType>>(
+                mbgl::style::conversion::makeConvertible(toRawStyleSpecValue((MGLStyleFunction<ObjCType> *) value)), error);
             NSCAssert(result, @(error.message.c_str()));
             return *result;
         } else {

platform/node/src/node_conversion.hpp

@@ -9,111 +9,136 @@
 #include <mbgl/util/optional.hpp>
 #include <mbgl/util/feature.hpp>
 #include <mbgl/style/conversion.hpp>
+#include <mbgl/style/conversion/geojson.hpp>
 
 namespace mbgl {
 namespace style {
 namespace conversion {
 
-inline bool isUndefined(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    return value->IsUndefined() || value->IsNull();
-}
+template <>
+class ConversionTraits<v8::Local<v8::Value>> {
+public:
+    static bool isUndefined(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        return value->IsUndefined() || value->IsNull();
+    }
 
-inline bool isArray(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    return value->IsArray();
-}
+    static bool isArray(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        return value->IsArray();
+    }
 
-inline std::size_t arrayLength(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    return value.As<v8::Array>()->Length();
-}
+    static std::size_t arrayLength(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        // const_cast because v8::Local<T>::As is not marked const until node v8.0
+        v8::Local<v8::Array> array = const_cast<v8::Local<v8::Value>&>(value).As<v8::Array>();
+        return array->Length();
+    }
 
-inline v8::Local<v8::Value> arrayMember(v8::Local<v8::Value> value, std::size_t i) {
-    Nan::EscapableHandleScope scope;
-    return scope.Escape(Nan::Get(value.As<v8::Array>(), i).ToLocalChecked());
-}
+    static v8::Local<v8::Value> arrayMember(const v8::Local<v8::Value>& value, std::size_t i) {
+        Nan::EscapableHandleScope scope;
+        // const_cast because v8::Local<T>::As is not marked const until node v8.0
+        v8::Local<v8::Array> array = const_cast<v8::Local<v8::Value>&>(value).As<v8::Array>();
+        return scope.Escape(Nan::Get(array, i).ToLocalChecked());
+    }
 
-inline bool isObject(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    return value->IsObject() && !value->IsArray();
-}
+    static bool isObject(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        return value->IsObject() && !value->IsArray();
+    }
 
-inline optional<v8::Local<v8::Value>> objectMember(v8::Local<v8::Value> value, const char * name) {
-    Nan::EscapableHandleScope scope;
-    if (!Nan::Has(Nan::To<v8::Object>(value).ToLocalChecked(), Nan::New(name).ToLocalChecked()).FromJust()) {
+    static optional<v8::Local<v8::Value>> objectMember(const v8::Local<v8::Value>& value, const char * name) {
+        Nan::EscapableHandleScope scope;
+        if (!Nan::Has(Nan::To<v8::Object>(value).ToLocalChecked(), Nan::New(name).ToLocalChecked()).FromJust()) {
+            return {};
+        }
+        Nan::MaybeLocal<v8::Value> result = Nan::Get(Nan::To<v8::Object>(value).ToLocalChecked(), Nan::New(name).ToLocalChecked());
+        if (result.IsEmpty()) {
+            return {};
+        }
+        return {scope.Escape(result.ToLocalChecked())};
+    }
+
+    template <class Fn>
+    static optional<Error> eachMember(const v8::Local<v8::Value>& value, Fn&& fn) {
+        Nan::HandleScope scope;
+        v8::Local<v8::Array> names = Nan::GetOwnPropertyNames(Nan::To<v8::Object>(value).ToLocalChecked()).ToLocalChecked();
+        for (uint32_t i = 0; i < names->Length(); ++i) {
+            v8::Local<v8::Value> k = Nan::Get(names, i).ToLocalChecked();
+            v8::Local<v8::Value> v = Nan::Get(Nan::To<v8::Object>(value).ToLocalChecked(), k).ToLocalChecked();
+            optional<Error> result = fn(*Nan::Utf8String(k), std::move(v));
+            if (result) {
+                return result;
+            }
+        }
         return {};
     }
-    Nan::MaybeLocal<v8::Value> result = Nan::Get(Nan::To<v8::Object>(value).ToLocalChecked(), Nan::New(name).ToLocalChecked());
-    if (result.IsEmpty()) {
-        return {};
-    }
-    return scope.Escape(result.ToLocalChecked());
-}
 
-template <class Fn>
-optional<Error> eachMember(v8::Local<v8::Value> value, Fn&& fn) {
-    Nan::HandleScope scope;
-    v8::Local<v8::Array> names = Nan::GetOwnPropertyNames(Nan::To<v8::Object>(value).ToLocalChecked()).ToLocalChecked();
-    for (uint32_t i = 0; i < names->Length(); ++i) {
-        v8::Local<v8::Value> k = Nan::Get(names, i).ToLocalChecked();
-        v8::Local<v8::Value> v = Nan::Get(Nan::To<v8::Object>(value).ToLocalChecked(), k).ToLocalChecked();
-        optional<Error> result = fn(*Nan::Utf8String(k), v);
-        if (result) {
-            return result;
+    static optional<bool> toBool(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        if (!value->IsBoolean()) {
+            return {};
+        }
+        return value->BooleanValue();
+    }
+
+    static optional<float> toNumber(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        if (!value->IsNumber()) {
+            return {};
+        }
+        return value->NumberValue();
+    }
+
+    static optional<double> toDouble(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        if (!value->IsNumber()) {
+            return {};
+        }
+        return value->NumberValue();
+    }
+
+    static optional<std::string> toString(const v8::Local<v8::Value>& value) {
+        Nan::HandleScope scope;
+        if (!value->IsString()) {
+            return {};
+        }
+        return std::string(*Nan::Utf8String(value));
+    }
+
+    static optional<Value> toValue(const v8::Local<v8::Value>& value) {
+        if (value->IsFalse()) {
+            return { false };
+        } else if (value->IsTrue()) {
+            return { true };
+        } else if (value->IsString()) {
+            return { std::string(*Nan::Utf8String(value)) };
+        } else if (value->IsUint32()) {
+            return { std::uint64_t(value->Uint32Value()) };
+        } else if (value->IsInt32()) {
+            return { std::int64_t(value->Int32Value()) };
+        } else if (value->IsNumber()) {
+            return { value->NumberValue() };
+        } else {
+            return {};
         }
     }
-    return {};
-}
 
-inline optional<bool> toBool(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    if (!value->IsBoolean()) {
-        return {};
+    static optional<GeoJSON> toGeoJSON(const v8::Local<v8::Value>& value, Error& error) {
+        try {
+            Nan::JSON JSON;
+            std::string string = *Nan::Utf8String(JSON.Stringify(value->ToObject()).ToLocalChecked());
+            return parseGeoJSON(string, error);
+        } catch (const std::exception& ex) {
+            error = { ex.what() };
+            return {};
+        }
     }
-    return value->BooleanValue();
-}
+};
 
-inline optional<float> toNumber(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    if (!value->IsNumber()) {
-        return {};
-    }
-    return value->NumberValue();
-}
-
-inline optional<double> toDouble(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    if (!value->IsNumber()) {
-        return {};
-    }
-    return value->NumberValue();
-}
-
-inline optional<std::string> toString(v8::Local<v8::Value> value) {
-    Nan::HandleScope scope;
-    if (!value->IsString()) {
-        return {};
-    }
-    return std::string(*Nan::Utf8String(value));
-}
-
-inline optional<Value> toValue(v8::Local<v8::Value> value) {
-    if (value->IsFalse()) {
-        return { false };
-    } else if (value->IsTrue()) {
-        return { true };
-    } else if (value->IsString()) {
-        return { std::string(*Nan::Utf8String(value)) };
-    } else if (value->IsUint32()) {
-        return { std::uint64_t(value->Uint32Value()) };
-    } else if (value->IsInt32()) {
-        return { std::int64_t(value->Int32Value()) };
-    } else if (value->IsNumber()) {
-        return { value->NumberValue() };
-    } else {
-        return {};
-    }
+template <class T, class...Args>
+optional<T> convert(const v8::Local<v8::Value>& value, Error& error, Args&&...args) {
+    return convert<T>(Convertible(value), error, std::forward<Args>(args)...);
 }
 
 } // namespace conversion

platform/node/src/node_geojson.hpp

@@ -1,17 +0,0 @@
-#include <mbgl/style/conversion/geojson.hpp>
-
-#include <string>
-namespace mbgl {
-namespace style {
-namespace conversion {
-
-template <>
-optional<GeoJSON> Converter<GeoJSON>::operator()(const v8::Local<v8::Value>& value, Error& error) const {
-    Nan::JSON JSON;
-    std::string string = *Nan::Utf8String(JSON.Stringify(value->ToObject()).ToLocalChecked());
-    return convert<GeoJSON>(string, error);
-}
-
-} // namespace conversion
-} // namespace style
-} // namespace mbgl

platform/node/src/node_map.cpp

@@ -2,7 +2,6 @@
 #include "node_request.hpp"
 #include "node_feature.hpp"
 #include "node_conversion.hpp"
-#include "node_geojson.hpp"
 
 #include <mbgl/util/exception.hpp>
 #include <mbgl/renderer/renderer.hpp>
@@ -10,6 +9,15 @@
 #include <mbgl/style/conversion/source.hpp>
 #include <mbgl/style/conversion/layer.hpp>
 #include <mbgl/style/conversion/filter.hpp>
+
+#include <mbgl/style/layers/background_layer.hpp>
+#include <mbgl/style/layers/circle_layer.hpp>
+#include <mbgl/style/layers/fill_layer.hpp>
+#include <mbgl/style/layers/fill_extrusion_layer.hpp>
+#include <mbgl/style/layers/line_layer.hpp>
+#include <mbgl/style/layers/raster_layer.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
+
 #include <mbgl/style/style.hpp>
 #include <mbgl/style/image.hpp>
 #include <mbgl/map/map_observer.hpp>
@@ -741,7 +749,7 @@ void NodeMap::SetLayoutProperty(const Nan::FunctionCallbackInfo<v8::Value>& info
         return Nan::ThrowTypeError("Second argument must be a string");
     }
 
-    mbgl::optional<Error> error = setLayoutProperty(*layer, *Nan::Utf8String(info[1]), info[2]);
+    mbgl::optional<Error> error = setLayoutProperty(*layer, *Nan::Utf8String(info[1]), Convertible(info[2]));
     if (error) {
         return Nan::ThrowTypeError(error->message.c_str());
     }
@@ -773,7 +781,7 @@ void NodeMap::SetPaintProperty(const Nan::FunctionCallbackInfo<v8::Value>& info)
         return Nan::ThrowTypeError("Second argument must be a string");
     }
 
-    mbgl::optional<Error> error = setPaintProperty(*layer, *Nan::Utf8String(info[1]), info[2]);
+    mbgl::optional<Error> error = setPaintProperty(*layer, *Nan::Utf8String(info[1]), Convertible(info[2]));
     if (error) {
         return Nan::ThrowTypeError(error->message.c_str());
     }

platform/qt/qt.cmake

@@ -60,6 +60,9 @@ set(MBGL_QT_FILESOURCE_FILES
 add_library(qmapboxgl SHARED
     platform/qt/include/qmapbox.hpp
     platform/qt/include/qmapboxgl.hpp
+    platform/qt/src/qt_conversion.hpp
+    platform/qt/src/qt_geojson.cpp
+    platform/qt/src/qt_geojson.hpp
     platform/qt/src/qmapbox.cpp
     platform/qt/src/qmapboxgl.cpp
     platform/qt/src/qmapboxgl_p.hpp

platform/qt/src/qmapboxgl.cpp

@@ -14,7 +14,17 @@
 #include <mbgl/style/conversion.hpp>
 #include <mbgl/style/conversion/layer.hpp>
 #include <mbgl/style/conversion/source.hpp>
+#include <mbgl/style/conversion/filter.hpp>
+#include <mbgl/style/conversion/geojson.hpp>
+#include <mbgl/style/filter.hpp>
 #include <mbgl/style/layers/custom_layer.hpp>
+#include <mbgl/style/layers/background_layer.hpp>
+#include <mbgl/style/layers/circle_layer.hpp>
+#include <mbgl/style/layers/fill_layer.hpp>
+#include <mbgl/style/layers/fill_extrusion_layer.hpp>
+#include <mbgl/style/layers/line_layer.hpp>
+#include <mbgl/style/layers/raster_layer.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
 #include <mbgl/style/sources/geojson_source.hpp>
 #include <mbgl/style/transition_options.hpp>
 #include <mbgl/style/image.hpp>

platform/qt/src/qt_conversion.hpp

@@ -1,120 +1,145 @@
 #pragma once
 
 #include <mbgl/style/conversion.hpp>
-#include <mbgl/util/feature.hpp>
+#include <mbgl/style/conversion/geojson.hpp>
 #include <mbgl/util/optional.hpp>
 
-#include <QMapbox>
-
-#include <QColor>
 #include <QVariant>
+#include <QColor>
+#include <QMapbox>
+#include "qt_geojson.hpp"
 
 namespace mbgl {
 namespace style {
 namespace conversion {
 
-inline bool isUndefined(const QVariant& value) {
-    return value.isNull() || !value.isValid();
-}
-
-inline bool isArray(const QVariant& value) {
-    return value.canConvert(QVariant::List);
-}
-
-inline std::size_t arrayLength(const QVariant& value) {
-    return value.toList().size();
-}
-
-inline QVariant arrayMember(const QVariant& value, std::size_t i) {
-    return value.toList()[i];
-}
-
-inline bool isObject(const QVariant& value) {
-    return value.canConvert(QVariant::Map)
-        || value.type() == QVariant::ByteArray
-#if QT_VERSION >= 0x050000
-        || QString(value.typeName()) == QStringLiteral("QMapbox::Feature");
-#else
-        || QString(value.typeName()) == QString("QMapbox::Feature");
-#endif
-}
-
-inline optional<QVariant> objectMember(const QVariant& value, const char* key) {
-    auto map = value.toMap();
-    auto iter = map.constFind(key);
-
-    if (iter != map.constEnd()) {
-        return iter.value();
-    } else {
-        return {};
+template <>
+class ConversionTraits<QVariant> {
+public:
+    static bool isUndefined(const QVariant& value) {
+        return value.isNull() || !value.isValid();
     }
-}
 
-using EachMemberFn = std::function<optional<Error>(const std::string&, const QVariant&)>;
+    static bool isArray(const QVariant& value) {
+        return value.canConvert(QVariant::List);
+    }
 
-optional<Error> eachMember(const QVariant& value, EachMemberFn&& fn) {
-    auto map = value.toMap();
-    auto iter = map.constBegin();
+    static std::size_t arrayLength(const QVariant& value) {
+        return value.toList().size();
+    }
 
-    while (iter != map.constEnd()) {
-        optional<Error> result = fn(iter.key().toStdString(), iter.value());
-        if (result) {
-            return result;
+    static QVariant arrayMember(const QVariant& value, std::size_t i) {
+        return value.toList()[i];
+    }
+
+    static bool isObject(const QVariant& value) {
+        return value.canConvert(QVariant::Map)
+            || value.type() == QVariant::ByteArray
+    #if QT_VERSION >= 0x050000
+            || QString(value.typeName()) == QStringLiteral("QMapbox::Feature");
+    #else
+            || QString(value.typeName()) == QString("QMapbox::Feature");
+    #endif
+    }
+
+    static optional<QVariant> objectMember(const QVariant& value, const char* key) {
+        auto map = value.toMap();
+        auto iter = map.constFind(key);
+
+        if (iter != map.constEnd()) {
+            return iter.value();
+        } else {
+            return {};
+        }
+    }
+
+    template <class Fn>
+    static optional<Error> eachMember(const QVariant& value, Fn&& fn) {
+        auto map = value.toMap();
+        auto iter = map.constBegin();
+
+        while (iter != map.constEnd()) {
+            optional<Error> result = fn(iter.key().toStdString(), QVariant(iter.value()));
+            if (result) {
+                return result;
+            }
+
+            ++iter;
         }
 
-        ++iter;
-    }
-
-    return {};
-}
-
-inline optional<bool> toBool(const QVariant& value) {
-    if (value.type() == QVariant::Bool) {
-        return value.toBool();
-    } else {
         return {};
     }
-}
 
-inline optional<float> toNumber(const QVariant& value) {
-    if (value.type() == QVariant::Int || value.type() == QVariant::Double) {
-        return value.toFloat();
-    } else {
-        return {};
+    static optional<bool> toBool(const QVariant& value) {
+        if (value.type() == QVariant::Bool) {
+            return value.toBool();
+        } else {
+            return {};
+        }
     }
-}
-inline optional<double> toDouble(const QVariant& value) {
-    if (value.type() == QVariant::Int || value.type() == QVariant::Double) {
-        return value.toDouble();
-    } else {
-        return {};
-    }
-}
 
-inline optional<std::string> toString(const QVariant& value) {
-    if (value.type() == QVariant::String) {
-        return value.toString().toStdString();
-    } else if (value.type() == QVariant::Color) {
-        return value.value<QColor>().name().toStdString();
-    } else {
-        return {};
+    static optional<float> toNumber(const QVariant& value) {
+        if (value.type() == QVariant::Int || value.type() == QVariant::Double) {
+            return value.toFloat();
+        } else {
+            return {};
+        }
     }
-}
 
-inline optional<Value> toValue(const QVariant& value) {
-    if (value.type() == QVariant::Bool) {
-        return { value.toBool() };
-    } else if (value.type() == QVariant::String) {
-        return { value.toString().toStdString() };
-    } else if (value.type() == QVariant::Color) {
-        return { value.value<QColor>().name().toStdString() };
-    } else if (value.type() == QVariant::Int) {
-        return { int64_t(value.toInt()) };
-    } else if (value.canConvert(QVariant::Double)) {
-        return { value.toDouble() };
-    } else {
-        return {};
+    static optional<double> toDouble(const QVariant& value) {
+        if (value.type() == QVariant::Int || value.type() == QVariant::Double) {
+            return value.toDouble();
+        } else {
+            return {};
+        }
     }
+
+    static optional<std::string> toString(const QVariant& value) {
+        if (value.type() == QVariant::String) {
+            return value.toString().toStdString();
+        } else if (value.type() == QVariant::Color) {
+            return value.value<QColor>().name().toStdString();
+        } else {
+            return {};
+        }
+    }
+
+    static optional<Value> toValue(const QVariant& value) {
+        if (value.type() == QVariant::Bool) {
+            return { value.toBool() };
+        } else if (value.type() == QVariant::String) {
+            return { value.toString().toStdString() };
+        } else if (value.type() == QVariant::Color) {
+            return { value.value<QColor>().name().toStdString() };
+        } else if (value.type() == QVariant::Int) {
+            return { int64_t(value.toInt()) };
+        } else if (value.canConvert(QVariant::Double)) {
+            return { value.toDouble() };
+        } else {
+            return {};
+        }
+    }
+
+    static optional<GeoJSON> toGeoJSON(const QVariant& value, Error& error) {
+    #if QT_VERSION >= 0x050000
+        if (value.typeName() == QStringLiteral("QMapbox::Feature")) {
+    #else
+        if (value.typeName() == QString("QMapbox::Feature")) {
+    #endif
+            return GeoJSON { asMapboxGLFeature(value.value<QMapbox::Feature>()) };
+        } else if (value.type() != QVariant::ByteArray) {
+            error = { "JSON data must be in QByteArray" };
+            return {};
+        }
+
+        QByteArray data = value.toByteArray();
+        return parseGeoJSON(std::string(data.constData(), data.size()), error);
+    }
+};
+
+template <class T, class...Args>
+optional<T> convert(const QVariant& value, Error& error, Args&&...args) {
+    return convert<T>(Convertible(value), error, std::forward<Args>(args)...);
 }
 
 } // namespace conversion

platform/qt/src/qt_geojson.cpp

@@ -0,0 +1,166 @@
+#include "qt_geojson.hpp"
+#include <mapbox/geojson.hpp>
+#include <mbgl/util/geometry.hpp>
+#include <mbgl/util/feature.hpp>
+
+namespace QMapbox {
+
+mbgl::Point<double> asMapboxGLPoint(const QMapbox::Coordinate &coordinate) {
+    return mbgl::Point<double> { coordinate.second, coordinate.first };
+}
+
+mbgl::MultiPoint<double> asMapboxGLMultiPoint(const QMapbox::Coordinates &multiPoint) {
+    mbgl::MultiPoint<double> mbglMultiPoint;
+    mbglMultiPoint.reserve(multiPoint.size());
+    for (const auto &point: multiPoint) {
+        mbglMultiPoint.emplace_back(asMapboxGLPoint(point));
+    }
+    return mbglMultiPoint;
+};
+
+mbgl::LineString<double> asMapboxGLLineString(const QMapbox::Coordinates &lineString) {
+    mbgl::LineString<double> mbglLineString;
+    mbglLineString.reserve(lineString.size());
+    for (const auto &coordinate : lineString) {
+        mbglLineString.emplace_back(asMapboxGLPoint(coordinate));
+    }
+    return mbglLineString;
+};
+
+mbgl::MultiLineString<double> asMapboxGLMultiLineString(const QMapbox::CoordinatesCollection &multiLineString) {
+    mbgl::MultiLineString<double> mbglMultiLineString;
+    mbglMultiLineString.reserve(multiLineString.size());
+    for (const auto &lineString : multiLineString) {
+        mbglMultiLineString.emplace_back(std::forward<mbgl::LineString<double>>(asMapboxGLLineString(lineString)));
+    }
+    return mbglMultiLineString;
+};
+
+mbgl::Polygon<double> asMapboxGLPolygon(const QMapbox::CoordinatesCollection &polygon) {
+    mbgl::Polygon<double> mbglPolygon;
+    mbglPolygon.reserve(polygon.size());
+    for (const auto &linearRing : polygon) {
+        mbgl::LinearRing<double> mbglLinearRing;
+        mbglLinearRing.reserve(linearRing.size());
+        for (const auto &coordinate: linearRing) {
+            mbglLinearRing.emplace_back(asMapboxGLPoint(coordinate));
+        }
+        mbglPolygon.emplace_back(std::move(mbglLinearRing));
+    }
+    return mbglPolygon;
+};
+
+mbgl::MultiPolygon<double> asMapboxGLMultiPolygon(const QMapbox::CoordinatesCollections &multiPolygon) {
+    mbgl::MultiPolygon<double> mbglMultiPolygon;
+    mbglMultiPolygon.reserve(multiPolygon.size());
+    for (const auto &polygon : multiPolygon) {
+        mbglMultiPolygon.emplace_back(std::forward<mbgl::Polygon<double>>(asMapboxGLPolygon(polygon)));
+    }
+    return mbglMultiPolygon;
+};
+
+mbgl::Value asMapboxGLPropertyValue(const QVariant &value) {
+    auto valueList = [](const QVariantList &list) {
+        std::vector<mbgl::Value> mbglList;
+        mbglList.reserve(list.size());
+        for (const auto& listValue : list) {
+            mbglList.emplace_back(asMapboxGLPropertyValue(listValue));
+        }
+        return mbglList;
+    };
+
+    auto valueMap = [](const QVariantMap &map) {
+        std::unordered_map<std::string, mbgl::Value> mbglMap;
+        mbglMap.reserve(map.size());
+        auto it = map.constBegin();
+        while (it != map.constEnd()) {
+            mbglMap.emplace(std::make_pair(it.key().toStdString(), asMapboxGLPropertyValue(it.value())));
+            ++it;
+        }
+        return mbglMap;
+    };
+
+    switch (value.type()) {
+#if QT_VERSION >= 0x050000
+    case QMetaType::UnknownType:
+#else
+    case QVariant::Invalid:
+#endif
+        return mbgl::NullValue {};
+    case QMetaType::Bool:
+        return { value.toBool() };
+    case QMetaType::ULongLong:
+        return { uint64_t(value.toULongLong()) };
+    case QMetaType::LongLong:
+        return { int64_t(value.toLongLong()) };
+    case QMetaType::Double:
+        return { value.toDouble() };
+    case QMetaType::QString:
+        return { value.toString().toStdString() };
+    case QMetaType::QVariantList:
+        return valueList(value.toList());
+    case QMetaType::QVariantMap:
+        return valueMap(value.toMap());
+    default:
+        qWarning() << "Unsupported feature property value:" << value;
+        return {};
+    }
+}
+
+mbgl::FeatureIdentifier asMapboxGLFeatureIdentifier(const QVariant &id) {
+    switch (id.type()) {
+#if QT_VERSION >= 0x050000
+    case QMetaType::UnknownType:
+#else
+    case QVariant::Invalid:
+#endif
+        return {};
+    case QMetaType::ULongLong:
+        return { uint64_t(id.toULongLong()) };
+    case QMetaType::LongLong:
+        return { int64_t(id.toLongLong()) };
+    case QMetaType::Double:
+        return { id.toDouble() };
+    case QMetaType::QString:
+        return { id.toString().toStdString() };
+    default:
+        qWarning() << "Unsupported feature identifier:" << id;
+        return {};
+    }
+}
+
+mbgl::Feature asMapboxGLFeature(const QMapbox::Feature &feature) {
+    mbgl::PropertyMap properties;
+    properties.reserve(feature.properties.size());
+    auto it = feature.properties.constBegin();
+    while (it != feature.properties.constEnd()) {
+        properties.emplace(std::make_pair(it.key().toStdString(), asMapboxGLPropertyValue(it.value())));
+    }
+
+    mbgl::FeatureIdentifier id = asMapboxGLFeatureIdentifier(feature.id);
+
+    if (feature.type == QMapbox::Feature::PointType) {
+        const QMapbox::Coordinates &points = feature.geometry.first().first();
+        if (points.size() == 1) {
+            return { asMapboxGLPoint(points.first()), std::move(properties), std::move(id) };
+        } else {
+            return { asMapboxGLMultiPoint(points), std::move(properties), std::move(id) };
+        }
+    } else if (feature.type == QMapbox::Feature::LineStringType) {
+        const QMapbox::CoordinatesCollection &lineStrings = feature.geometry.first();
+        if (lineStrings.size() == 1) {
+            return { asMapboxGLLineString(lineStrings.first()), std::move(properties), std::move(id) };
+        } else {
+            return { asMapboxGLMultiLineString(lineStrings), std::move(properties), std::move(id) };
+        }
+    } else { // PolygonType
+        const QMapbox::CoordinatesCollections &polygons = feature.geometry;
+        if (polygons.size() == 1) {
+            return { asMapboxGLPolygon(polygons.first()), std::move(properties), std::move(id) };
+        } else {
+            return { asMapboxGLMultiPolygon(polygons), std::move(properties), std::move(id) };
+        }
+    }
+};
+
+} // namespace QMapbox

platform/qt/src/qt_geojson.hpp

@@ -1,7 +1,8 @@
 #pragma once
 
 #include <mapbox/geojson.hpp>
-#include <mbgl/style/conversion/geojson.hpp>
+#include <mbgl/util/geometry.hpp>
+#include <mbgl/util/feature.hpp>
 
 #include <QMapbox>
 
@@ -13,187 +14,14 @@
 
 namespace QMapbox {
 
-mbgl::Point<double> asMapboxGLPoint(const QMapbox::Coordinate &coordinate) {
-    return mbgl::Point<double> { coordinate.second, coordinate.first };
-}
-
-mbgl::MultiPoint<double> asMapboxGLMultiPoint(const QMapbox::Coordinates &multiPoint) {
-    mbgl::MultiPoint<double> mbglMultiPoint;
-    mbglMultiPoint.reserve(multiPoint.size());
-    for (const auto &point: multiPoint) {
-        mbglMultiPoint.emplace_back(asMapboxGLPoint(point));
-    }
-    return mbglMultiPoint;
-};
-
-mbgl::LineString<double> asMapboxGLLineString(const QMapbox::Coordinates &lineString) {
-    mbgl::LineString<double> mbglLineString;
-    mbglLineString.reserve(lineString.size());
-    for (const auto &coordinate : lineString) {
-        mbglLineString.emplace_back(asMapboxGLPoint(coordinate));
-    }
-    return mbglLineString;
-};
-
-mbgl::MultiLineString<double> asMapboxGLMultiLineString(const QMapbox::CoordinatesCollection &multiLineString) {
-    mbgl::MultiLineString<double> mbglMultiLineString;
-    mbglMultiLineString.reserve(multiLineString.size());
-    for (const auto &lineString : multiLineString) {
-        mbglMultiLineString.emplace_back(std::forward<mbgl::LineString<double>>(asMapboxGLLineString(lineString)));
-    }
-    return mbglMultiLineString;
-};
-
-mbgl::Polygon<double> asMapboxGLPolygon(const QMapbox::CoordinatesCollection &polygon) {
-    mbgl::Polygon<double> mbglPolygon;
-    mbglPolygon.reserve(polygon.size());
-    for (const auto &linearRing : polygon) {
-        mbgl::LinearRing<double> mbglLinearRing;
-        mbglLinearRing.reserve(linearRing.size());
-        for (const auto &coordinate: linearRing) {
-            mbglLinearRing.emplace_back(asMapboxGLPoint(coordinate));
-        }
-        mbglPolygon.emplace_back(std::move(mbglLinearRing));
-    }
-    return mbglPolygon;
-};
-
-mbgl::MultiPolygon<double> asMapboxGLMultiPolygon(const QMapbox::CoordinatesCollections &multiPolygon) {
-    mbgl::MultiPolygon<double> mbglMultiPolygon;
-    mbglMultiPolygon.reserve(multiPolygon.size());
-    for (const auto &polygon : multiPolygon) {
-        mbglMultiPolygon.emplace_back(std::forward<mbgl::Polygon<double>>(asMapboxGLPolygon(polygon)));
-    }
-    return mbglMultiPolygon;
-};
-
-mbgl::Value asMapboxGLPropertyValue(const QVariant &value) {
-    auto valueList = [](const QVariantList &list) {
-        std::vector<mbgl::Value> mbglList;
-        mbglList.reserve(list.size());
-        for (const auto& listValue : list) {
-            mbglList.emplace_back(asMapboxGLPropertyValue(listValue));
-        }
-        return mbglList;
-    };
-
-    auto valueMap = [](const QVariantMap &map) {
-        std::unordered_map<std::string, mbgl::Value> mbglMap;
-        mbglMap.reserve(map.size());
-        auto it = map.constBegin();
-        while (it != map.constEnd()) {
-            mbglMap.emplace(std::make_pair(it.key().toStdString(), asMapboxGLPropertyValue(it.value())));
-            ++it;
-        }
-        return mbglMap;
-    };
-
-    switch (value.type()) {
-#if QT_VERSION >= 0x050000
-    case QMetaType::UnknownType:
-#else
-    case QVariant::Invalid:
-#endif
-        return mbgl::NullValue {};
-    case QMetaType::Bool:
-        return { value.toBool() };
-    case QMetaType::ULongLong:
-        return { uint64_t(value.toULongLong()) };
-    case QMetaType::LongLong:
-        return { int64_t(value.toLongLong()) };
-    case QMetaType::Double:
-        return { value.toDouble() };
-    case QMetaType::QString:
-        return { value.toString().toStdString() };
-    case QMetaType::QVariantList:
-        return valueList(value.toList());
-    case QMetaType::QVariantMap:
-        return valueMap(value.toMap());
-    default:
-        qWarning() << "Unsupported feature property value:" << value;
-        return {};
-    }
-}
-
-mbgl::FeatureIdentifier asMapboxGLFeatureIdentifier(const QVariant &id) {
-    switch (id.type()) {
-#if QT_VERSION >= 0x050000
-    case QMetaType::UnknownType:
-#else
-    case QVariant::Invalid:
-#endif
-        return {};
-    case QMetaType::ULongLong:
-        return { uint64_t(id.toULongLong()) };
-    case QMetaType::LongLong:
-        return { int64_t(id.toLongLong()) };
-    case QMetaType::Double:
-        return { id.toDouble() };
-    case QMetaType::QString:
-        return { id.toString().toStdString() };
-    default:
-        qWarning() << "Unsupported feature identifier:" << id;
-        return {};
-    }
-}
-
-mbgl::Feature asMapboxGLFeature(const QMapbox::Feature &feature) {
-    mbgl::PropertyMap properties;
-    properties.reserve(feature.properties.size());
-    auto it = feature.properties.constBegin();
-    while (it != feature.properties.constEnd()) {
-        properties.emplace(std::make_pair(it.key().toStdString(), asMapboxGLPropertyValue(it.value())));
-    }
-
-    mbgl::FeatureIdentifier id = asMapboxGLFeatureIdentifier(feature.id);
-
-    if (feature.type == QMapbox::Feature::PointType) {
-        const QMapbox::Coordinates &points = feature.geometry.first().first();
-        if (points.size() == 1) {
-            return { asMapboxGLPoint(points.first()), std::move(properties), std::move(id) };
-        } else {
-            return { asMapboxGLMultiPoint(points), std::move(properties), std::move(id) };
-        }
-    } else if (feature.type == QMapbox::Feature::LineStringType) {
-        const QMapbox::CoordinatesCollection &lineStrings = feature.geometry.first();
-        if (lineStrings.size() == 1) {
-            return { asMapboxGLLineString(lineStrings.first()), std::move(properties), std::move(id) };
-        } else {
-            return { asMapboxGLMultiLineString(lineStrings), std::move(properties), std::move(id) };
-        }
-    } else { // PolygonType
-        const QMapbox::CoordinatesCollections &polygons = feature.geometry;
-        if (polygons.size() == 1) {
-            return { asMapboxGLPolygon(polygons.first()), std::move(properties), std::move(id) };
-        } else {
-            return { asMapboxGLMultiPolygon(polygons), std::move(properties), std::move(id) };
-        }
-    }
-};
+mbgl::Point<double> asMapboxGLPoint(const QMapbox::Coordinate &coordinate);
+mbgl::MultiPoint<double> asMapboxGLMultiPoint(const QMapbox::Coordinates &multiPoint);
+mbgl::LineString<double> asMapboxGLLineString(const QMapbox::Coordinates &lineString);
+mbgl::MultiLineString<double> asMapboxGLMultiLineString(const QMapbox::CoordinatesCollection &multiLineString);
+mbgl::Polygon<double> asMapboxGLPolygon(const QMapbox::CoordinatesCollection &polygon);
+mbgl::MultiPolygon<double> asMapboxGLMultiPolygon(const QMapbox::CoordinatesCollections &multiPolygon);
+mbgl::Value asMapboxGLPropertyValue(const QVariant &value);
+mbgl::FeatureIdentifier asMapboxGLFeatureIdentifier(const QVariant &id);
+mbgl::Feature asMapboxGLFeature(const QMapbox::Feature &feature);
 
 } // namespace QMapbox
-
-namespace mbgl {
-namespace style {
-namespace conversion {
-
-template <>
-optional<GeoJSON> Converter<GeoJSON>::operator()(const QVariant& value, Error& error) const {
-#if QT_VERSION >= 0x050000
-    if (value.typeName() == QStringLiteral("QMapbox::Feature")) {
-#else
-    if (value.typeName() == QString("QMapbox::Feature")) {
-#endif
-        return GeoJSON { asMapboxGLFeature(value.value<QMapbox::Feature>()) };
-    } else if (value.type() != QVariant::ByteArray) {
-        error = { "JSON data must be in QByteArray" };
-        return {};
-    }
-
-    QByteArray data = value.toByteArray();
-    return convert<GeoJSON>(std::string(data.constData(), data.size()), error);
-}
-
-} // namespace conversion
-} // namespace style
-} // namespace mbgl

scripts/generate-style-code.js

@@ -186,8 +186,8 @@ for (const layer of layers) {
   writeIfModified(`src/mbgl/style/layers/${layerFileName}_layer_properties.cpp`, propertiesCpp(layer));
 }
 
-const propertySettersHpp = ejs.compile(fs.readFileSync('include/mbgl/style/conversion/make_property_setters.hpp.ejs', 'utf8'), {strict: true});
-writeIfModified('include/mbgl/style/conversion/make_property_setters.hpp', propertySettersHpp({layers: layers}));
+const propertySettersHpp = ejs.compile(fs.readFileSync('src/mbgl/style/conversion/make_property_setters.hpp.ejs', 'utf8'), {strict: true});
+writeIfModified('src/mbgl/style/conversion/make_property_setters.hpp', propertySettersHpp({layers: layers}));
 
 // Light
 const lightProperties = Object.keys(spec[`light`]).reduce((memo, name) => {

src/mbgl/style/conversion/constant.cpp

@@ -0,0 +1,94 @@
+#include <mbgl/style/conversion/constant.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<bool> Converter<bool>::operator()(const Convertible& value, Error& error) const {
+    optional<bool> converted = toBool(value);
+    if (!converted) {
+        error = { "value must be a boolean" };
+        return {};
+    }
+    return *converted;
+}
+
+optional<float> Converter<float>::operator()(const Convertible& value, Error& error) const {
+    optional<float> converted = toNumber(value);
+    if (!converted) {
+        error = { "value must be a number" };
+        return {};
+    }
+    return *converted;
+}
+
+optional<std::string> Converter<std::string>::operator()(const Convertible& value, Error& error) const {
+    optional<std::string> converted = toString(value);
+    if (!converted) {
+        error = { "value must be a string" };
+        return {};
+    }
+    return *converted;
+}
+
+optional<Color> Converter<Color>::operator()(const Convertible& value, Error& error) const {
+    optional<std::string> string = toString(value);
+    if (!string) {
+        error = { "value must be a string" };
+        return {};
+    }
+
+    optional<Color> color = Color::parse(*string);
+    if (!color) {
+        error = { "value must be a valid color" };
+        return {};
+    }
+
+    return *color;
+}
+
+optional<std::vector<float>> Converter<std::vector<float>>::operator()(const Convertible& value, Error& error) const {
+    if (!isArray(value)) {
+        error = { "value must be an array" };
+        return {};
+    }
+
+    std::vector<float> result;
+    result.reserve(arrayLength(value));
+
+    for (std::size_t i = 0; i < arrayLength(value); ++i) {
+        optional<float> number = toNumber(arrayMember(value, i));
+        if (!number) {
+            error = { "value must be an array of numbers" };
+            return {};
+        }
+        result.push_back(*number);
+    }
+
+    return result;
+}
+
+optional<std::vector<std::string>> Converter<std::vector<std::string>>::operator()(const Convertible& value, Error& error) const {
+    if (!isArray(value)) {
+        error = { "value must be an array" };
+        return {};
+    }
+
+    std::vector<std::string> result;
+    result.reserve(arrayLength(value));
+
+    for (std::size_t i = 0; i < arrayLength(value); ++i) {
+        optional<std::string> string = toString(arrayMember(value, i));
+        if (!string) {
+            error = { "value must be an array of strings" };
+            return {};
+        }
+        result.push_back(*string);
+    }
+
+    return result;
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/coordinate.cpp

@@ -0,0 +1,29 @@
+#include <mbgl/style/conversion/coordinate.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<LatLng> Converter<LatLng>::operator() (const Convertible& value, Error& error) const {
+    if (!isArray(value) || arrayLength(value) < 2 ) {
+        error = { "coordinate array must contain numeric longitude and latitude values" };
+        return {};
+    }
+    //Style spec uses GeoJSON convention for specifying coordinates
+    optional<double> latitude = toDouble(arrayMember(value, 1));
+    optional<double> longitude = toDouble(arrayMember(value, 0));
+
+    if (!latitude || !longitude) {
+        error = { "coordinate array must contain numeric longitude and latitude values" };
+        return {};
+    }
+    if (*latitude < -90 || *latitude > 90 ){
+        error = { "coordinate latitude must be between -90 and 90" };
+        return {};
+    }
+    return LatLng(*latitude, *longitude);
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/filter.cpp

@@ -0,0 +1,248 @@
+#include <mbgl/style/conversion/filter.hpp>
+#include <mbgl/util/geometry.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+static optional<Value> normalizeValue(const optional<Value>& value, Error& error) {
+    if (!value) {
+        error = { "filter expression value must be a boolean, number, or string" };
+        return {};
+    } else {
+        return *value;
+    }
+}
+
+static optional<FeatureType> toFeatureType(const Convertible& value, Error& error) {
+    optional<std::string> type = toString(value);
+    if (!type) {
+        error = { "value for $type filter must be a string" };
+        return {};
+    } else if (*type == "Point") {
+        return FeatureType::Point;
+    } else if (*type == "LineString") {
+        return FeatureType::LineString;
+    } else if (*type == "Polygon") {
+        return FeatureType::Polygon;
+    } else {
+        error = { "value for $type filter must be Point, LineString, or Polygon" };
+        return {};
+    }
+}
+
+static optional<FeatureIdentifier> toFeatureIdentifier(const Convertible& value, Error& error) {
+    optional<Value> identifier = toValue(value);
+    if (!identifier) {
+        error = { "filter expression value must be a boolean, number, or string" };
+        return {};
+    } else {
+        return (*identifier).match(
+            [] (uint64_t t) -> optional<FeatureIdentifier> { return { t }; },
+            [] ( int64_t t) -> optional<FeatureIdentifier> { return { t }; },
+            [] (  double t) -> optional<FeatureIdentifier> { return { t }; },
+            [] (const std::string& t) -> optional<FeatureIdentifier> { return { t }; },
+            [&] (const auto&) -> optional<FeatureIdentifier> {
+                error = { "filter expression value must be a boolean, number, or string" };
+                return {};
+            });
+    }
+}
+
+template <class FilterType, class IdentifierFilterType>
+optional<Filter> convertUnaryFilter(const Convertible& value, Error& error) {
+    if (arrayLength(value) < 2) {
+        error = { "filter expression must have 2 elements" };
+        return {};
+    }
+
+    optional<std::string> key = toString(arrayMember(value, 1));
+    if (!key) {
+        error = { "filter expression key must be a string" };
+        return {};
+    }
+
+    if (*key == "$id") {
+        return { IdentifierFilterType {} };
+    } else {
+        return { FilterType { *key } };
+    }
+}
+
+template <class FilterType, class TypeFilterType, class IdentifierFilterType>
+optional<Filter> convertEqualityFilter(const Convertible& value, Error& error) {
+    if (arrayLength(value) < 3) {
+        error = { "filter expression must have 3 elements" };
+        return {};
+    }
+
+    optional<std::string> key = toString(arrayMember(value, 1));
+    if (!key) {
+        error = { "filter expression key must be a string" };
+        return {};
+    }
+
+    if (*key == "$type") {
+        optional<FeatureType> filterValue = toFeatureType(arrayMember(value, 2), error);
+        if (!filterValue) {
+            return {};
+        }
+
+        return { TypeFilterType { *filterValue } };
+
+    } else if (*key == "$id") {
+        optional<FeatureIdentifier> filterValue = toFeatureIdentifier(arrayMember(value, 2), error);
+        if (!filterValue) {
+            return {};
+        }
+
+        return { IdentifierFilterType { *filterValue } };
+
+    } else {
+        optional<Value> filterValue = normalizeValue(toValue(arrayMember(value, 2)), error);
+        if (!filterValue) {
+            return {};
+        }
+
+        return { FilterType { *key, *filterValue } };
+    }
+}
+
+template <class FilterType>
+optional<Filter> convertBinaryFilter(const Convertible& value, Error& error) {
+    if (arrayLength(value) < 3) {
+        error = { "filter expression must have 3 elements" };
+        return {};
+    }
+
+    optional<std::string> key = toString(arrayMember(value, 1));
+    if (!key) {
+        error = { "filter expression key must be a string" };
+        return {};
+    }
+
+    optional<Value> filterValue = normalizeValue(toValue(arrayMember(value, 2)), error);
+    if (!filterValue) {
+        return {};
+    }
+
+    return { FilterType { *key, *filterValue } };
+}
+
+template <class FilterType, class TypeFilterType, class IdentifierFilterType>
+optional<Filter> convertSetFilter(const Convertible& value, Error& error) {
+    if (arrayLength(value) < 2) {
+        error = { "filter expression must at least 2 elements" };
+        return {};
+    }
+
+    optional<std::string> key = toString(arrayMember(value, 1));
+    if (!key) {
+        error = { "filter expression key must be a string" };
+        return {};
+    }
+
+    if (*key == "$type") {
+        std::vector<FeatureType> values;
+        for (std::size_t i = 2; i < arrayLength(value); ++i) {
+            optional<FeatureType> filterValue = toFeatureType(arrayMember(value, i), error);
+            if (!filterValue) {
+                return {};
+            }
+            values.push_back(*filterValue);
+        }
+
+        return { TypeFilterType { std::move(values) } };
+
+    } else if (*key == "$id") {
+        std::vector<FeatureIdentifier> values;
+        for (std::size_t i = 2; i < arrayLength(value); ++i) {
+            optional<FeatureIdentifier> filterValue = toFeatureIdentifier(arrayMember(value, i), error);
+            if (!filterValue) {
+                return {};
+            }
+            values.push_back(*filterValue);
+        }
+
+        return { IdentifierFilterType { std::move(values) } };
+
+    } else {
+        std::vector<Value> values;
+        for (std::size_t i = 2; i < arrayLength(value); ++i) {
+            optional<Value> filterValue = normalizeValue(toValue(arrayMember(value, i)), error);
+            if (!filterValue) {
+                return {};
+            }
+            values.push_back(*filterValue);
+        }
+
+        return { FilterType { *key, std::move(values) } };
+    }
+}
+
+template <class FilterType>
+optional<Filter> convertCompoundFilter(const Convertible& value, Error& error) {
+    std::vector<Filter> filters;
+    for (std::size_t i = 1; i < arrayLength(value); ++i) {
+        optional<Filter> element = convert<Filter>(arrayMember(value, i), error);
+        if (!element) {
+            return {};
+        }
+        filters.push_back(*element);
+    }
+
+    return { FilterType { std::move(filters) } };
+}
+
+optional<Filter> Converter<Filter>::operator()(const Convertible& value, Error& error) const {
+    if (!isArray(value)) {
+        error = { "filter expression must be an array" };
+        return {};
+    }
+
+    if (arrayLength(value) < 1) {
+        error = { "filter expression must have at least 1 element" };
+        return {};
+    }
+
+    optional<std::string> op = toString(arrayMember(value, 0));
+    if (!op) {
+        error = { "filter operator must be a string" };
+        return {};
+    }
+
+    if (*op == "==") {
+        return convertEqualityFilter<EqualsFilter, TypeEqualsFilter, IdentifierEqualsFilter>(value, error);
+    } else if (*op == "!=") {
+        return convertEqualityFilter<NotEqualsFilter, TypeNotEqualsFilter, IdentifierNotEqualsFilter>(value, error);
+    } else if (*op == ">") {
+        return convertBinaryFilter<GreaterThanFilter>(value, error);
+    } else if (*op == ">=") {
+        return convertBinaryFilter<GreaterThanEqualsFilter>(value, error);
+    } else if (*op == "<") {
+        return convertBinaryFilter<LessThanFilter>(value, error);
+    } else if (*op == "<=") {
+        return convertBinaryFilter<LessThanEqualsFilter>(value, error);
+    } else if (*op == "in") {
+        return convertSetFilter<InFilter, TypeInFilter, IdentifierInFilter>(value, error);
+    } else if (*op == "!in") {
+        return convertSetFilter<NotInFilter, TypeNotInFilter, IdentifierNotInFilter>(value, error);
+    } else if (*op == "all") {
+        return convertCompoundFilter<AllFilter>(value, error);
+    } else if (*op == "any") {
+        return convertCompoundFilter<AnyFilter>(value, error);
+    } else if (*op == "none") {
+        return convertCompoundFilter<NoneFilter>(value, error);
+    } else if (*op == "has") {
+        return convertUnaryFilter<HasFilter, HasIdentifierFilter>(value, error);
+    } else if (*op == "!has") {
+       return convertUnaryFilter<NotHasFilter, NotHasIdentifierFilter>(value, error);
+    }
+
+    error = { R"(filter operator must be one of "==", "!=", ">", ">=", "<", "<=", "in", "!in", "all", "any", "none", "has", or "!has")" };
+    return {};
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/geojson.cpp

@@ -1,26 +1,16 @@
 #include <mbgl/style/conversion/geojson.hpp>
 #include <mbgl/style/conversion/json.hpp>
-#include <mbgl/util/rapidjson.hpp>
-
-#include <mapbox/geojson.hpp>
-#include <mapbox/geojson/rapidjson.hpp>
 
 namespace mbgl {
 namespace style {
 namespace conversion {
 
-optional<GeoJSON> Converter<GeoJSON>::operator()(const std::string& value, Error& error) const {
-    return convertJSON<GeoJSON>(value, error);
+optional<GeoJSON> Converter<GeoJSON>::operator()(const Convertible& value, Error& error) const {
+    return toGeoJSON(value, error);
 }
 
-template <>
-optional<GeoJSON> Converter<GeoJSON>::operator()(const JSValue& value, Error& error) const {
-    try {
-        return mapbox::geojson::convert(value);
-    } catch (const std::exception& ex) {
-        error = { ex.what() };
-        return {};
-    }
+optional<GeoJSON> parseGeoJSON(const std::string& value, Error& error) {
+    return convertJSON<GeoJSON>(value, error);
 }
 
 } // namespace conversion

src/mbgl/style/conversion/geojson_options.cpp

@@ -0,0 +1,85 @@
+#include <mbgl/style/conversion/geojson_options.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<GeoJSONOptions> Converter<GeoJSONOptions>::operator()(const Convertible& value, Error& error) const {
+    GeoJSONOptions options;
+
+    const auto minzoomValue = objectMember(value, "minzoom");
+    if (minzoomValue) {
+        if (toNumber(*minzoomValue)) {
+            options.minzoom = static_cast<uint8_t>(*toNumber(*minzoomValue));
+        } else {
+            error = { "GeoJSON source minzoom value must be a number" };
+            return {};
+        }
+    }
+
+    const auto maxzoomValue = objectMember(value, "maxzoom");
+    if (maxzoomValue) {
+        if (toNumber(*maxzoomValue)) {
+            options.maxzoom = static_cast<uint8_t>(*toNumber(*maxzoomValue));
+        } else {
+            error = { "GeoJSON source maxzoom value must be a number" };
+            return {};
+        }
+    }
+
+    const auto bufferValue = objectMember(value, "buffer");
+    if (bufferValue) {
+        if (toNumber(*bufferValue)) {
+            options.buffer = static_cast<uint16_t>(*toNumber(*bufferValue));
+        } else {
+            error = { "GeoJSON source buffer value must be a number" };
+            return {};
+        }
+    }
+
+    const auto toleranceValue = objectMember(value, "tolerance");
+    if (toleranceValue) {
+        if (toNumber(*toleranceValue)) {
+            options.tolerance = static_cast<double>(*toNumber(*toleranceValue));
+        } else {
+            error = { "GeoJSON source tolerance value must be a number" };
+            return {};
+        }
+    }
+
+    const auto clusterValue = objectMember(value, "cluster");
+    if (clusterValue) {
+        if (toBool(*clusterValue)) {
+            options.cluster = *toBool(*clusterValue);
+        } else {
+            error = { "GeoJSON source cluster value must be a boolean" };
+            return {};
+        }
+    }
+
+    const auto clusterMaxZoomValue = objectMember(value, "clusterMaxZoom");
+    if (clusterMaxZoomValue) {
+        if (toNumber(*clusterMaxZoomValue)) {
+            options.clusterMaxZoom = static_cast<uint8_t>(*toNumber(*clusterMaxZoomValue));
+        } else {
+            error = { "GeoJSON source clusterMaxZoom value must be a number" };
+            return {};
+        }
+    }
+
+    const auto clusterRadiusValue = objectMember(value, "clusterRadius");
+    if (clusterRadiusValue) {
+        if (toNumber(*clusterRadiusValue)) {
+            options.clusterRadius = static_cast<double>(*toNumber(*clusterRadiusValue));
+        } else {
+            error = { "GeoJSON source clusterRadius value must be a number" };
+            return {};
+        }
+    }
+
+    return { options };
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/json.hpp

@@ -20,7 +20,7 @@ optional<T> convertJSON(const std::string& json, Error& error, Args&&...args) {
         return {};
     }
 
-    return convert<T, JSValue>(document, error, std::forward<Args>(args)...);
+    return convert<T>(document, error, std::forward<Args>(args)...);
 }
 
 } // namespace conversion

src/mbgl/style/conversion/layer.cpp

@@ -0,0 +1,206 @@
+#include <mbgl/style/conversion/layer.hpp>
+#include <mbgl/style/conversion/constant.hpp>
+#include <mbgl/style/conversion/filter.hpp>
+#include <mbgl/style/conversion/make_property_setters.hpp>
+#include <mbgl/style/layers/background_layer.hpp>
+#include <mbgl/style/layers/circle_layer.hpp>
+#include <mbgl/style/layers/fill_layer.hpp>
+#include <mbgl/style/layers/fill_extrusion_layer.hpp>
+#include <mbgl/style/layers/line_layer.hpp>
+#include <mbgl/style/layers/raster_layer.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<Error> setLayoutProperty(Layer& layer, const std::string& name, const Convertible& value) {
+    static const auto setters = makeLayoutPropertySetters();
+    auto it = setters.find(name);
+    if (it == setters.end()) {
+        return Error { "property not found" };
+    }
+    return it->second(layer, value);
+}
+
+optional<Error> setPaintProperty(Layer& layer, const std::string& name, const Convertible& value) {
+    static const auto setters = makePaintPropertySetters();
+    auto it = setters.find(name);
+    if (it == setters.end()) {
+        return Error { "property not found" };
+    }
+    return it->second(layer, value);
+}
+
+optional<Error> setPaintProperties(Layer& layer, const Convertible& value) {
+    auto paintValue = objectMember(value, "paint");
+    if (!paintValue) {
+        return {};
+    }
+    return eachMember(*paintValue, [&] (const std::string& k, const Convertible& v) {
+        return setPaintProperty(layer, k, v);
+    });
+}
+
+template <class LayerType>
+optional<std::unique_ptr<Layer>> convertVectorLayer(const std::string& id, const Convertible& value, Error& error) {
+    auto sourceValue = objectMember(value, "source");
+    if (!sourceValue) {
+        error = { "layer must have a source" };
+        return {};
+    }
+
+    optional<std::string> source = toString(*sourceValue);
+    if (!source) {
+        error = { "layer source must be a string" };
+        return {};
+    }
+
+    std::unique_ptr<LayerType> layer = std::make_unique<LayerType>(id, *source);
+
+    auto sourceLayerValue = objectMember(value, "source-layer");
+    if (sourceLayerValue) {
+        optional<std::string> sourceLayer = toString(*sourceLayerValue);
+        if (!sourceLayer) {
+            error = { "layer source-layer must be a string" };
+            return {};
+        }
+        layer->setSourceLayer(*sourceLayer);
+    }
+
+    auto filterValue = objectMember(value, "filter");
+    if (filterValue) {
+        optional<Filter> filter = convert<Filter>(*filterValue, error);
+        if (!filter) {
+            return {};
+        }
+        layer->setFilter(*filter);
+    }
+
+    return { std::move(layer) };
+}
+
+static optional<std::unique_ptr<Layer>> convertRasterLayer(const std::string& id, const Convertible& value, Error& error) {
+    auto sourceValue = objectMember(value, "source");
+    if (!sourceValue) {
+        error = { "layer must have a source" };
+        return {};
+    }
+
+    optional<std::string> source = toString(*sourceValue);
+    if (!source) {
+        error = { "layer source must be a string" };
+        return {};
+    }
+
+    return { std::make_unique<RasterLayer>(id, *source) };
+}
+
+static optional<std::unique_ptr<Layer>> convertBackgroundLayer(const std::string& id, const Convertible&, Error&) {
+    return { std::make_unique<BackgroundLayer>(id) };
+}
+
+optional<std::unique_ptr<Layer>> Converter<std::unique_ptr<Layer>>::operator()(const Convertible& value, Error& error) const {
+    if (!isObject(value)) {
+        error = { "layer must be an object" };
+        return {};
+    }
+
+    auto idValue = objectMember(value, "id");
+    if (!idValue) {
+        error = { "layer must have an id" };
+        return {};
+    }
+
+    optional<std::string> id = toString(*idValue);
+    if (!id) {
+        error = { "layer id must be a string" };
+        return {};
+    }
+
+    auto typeValue = objectMember(value, "type");
+    if (!typeValue) {
+        error = { "layer must have a type" };
+        return {};
+    }
+
+    optional<std::string> type = toString(*typeValue);
+    if (!type) {
+        error = { "layer type must be a string" };
+        return {};
+    }
+
+    optional<std::unique_ptr<Layer>> converted;
+
+    if (*type == "fill") {
+        converted = convertVectorLayer<FillLayer>(*id, value, error);
+    } else if (*type == "fill-extrusion") {
+        converted = convertVectorLayer<FillExtrusionLayer>(*id, value, error);
+    } else if (*type == "line") {
+        converted = convertVectorLayer<LineLayer>(*id, value, error);
+    } else if (*type == "circle") {
+        converted = convertVectorLayer<CircleLayer>(*id, value, error);
+    } else if (*type == "symbol") {
+        converted = convertVectorLayer<SymbolLayer>(*id, value, error);
+    } else if (*type == "raster") {
+        converted = convertRasterLayer(*id, value, error);
+    } else if (*type == "background") {
+        converted = convertBackgroundLayer(*id, value, error);
+    } else {
+        error = { "invalid layer type" };
+        return {};
+    }
+
+    if (!converted) {
+        return converted;
+    }
+
+    std::unique_ptr<Layer> layer = std::move(*converted);
+
+    auto minzoomValue = objectMember(value, "minzoom");
+    if (minzoomValue) {
+        optional<float> minzoom = toNumber(*minzoomValue);
+        if (!minzoom) {
+            error = { "minzoom must be numeric" };
+            return {};
+        }
+        layer->setMinZoom(*minzoom);
+    }
+
+    auto maxzoomValue = objectMember(value, "maxzoom");
+    if (maxzoomValue) {
+        optional<float> maxzoom = toNumber(*maxzoomValue);
+        if (!maxzoom) {
+            error = { "maxzoom must be numeric" };
+            return {};
+        }
+        layer->setMaxZoom(*maxzoom);
+    }
+
+    auto layoutValue = objectMember(value, "layout");
+    if (layoutValue) {
+        if (!isObject(*layoutValue)) {
+            error = { "layout must be an object" };
+            return {};
+        }
+        optional<Error> error_ = eachMember(*layoutValue, [&] (const std::string& k, const Convertible& v) {
+            return setLayoutProperty(*layer, k, v);
+        });
+        if (error_) {
+            error = *error_;
+            return {};
+        }
+    }
+
+    optional<Error> error_ = setPaintProperties(*layer, value);
+    if (error_) {
+        error = *error_;
+        return {};
+    }
+
+    return std::move(layer);
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/light.cpp

@@ -0,0 +1,115 @@
+#include <mbgl/style/conversion/light.hpp>
+#include <mbgl/style/conversion/position.hpp>
+#include <mbgl/style/conversion/property_value.hpp>
+#include <mbgl/style/conversion/transition_options.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<Light> Converter<Light>::operator()(const Convertible& value, Error& error) const {
+    if (!isObject(value)) {
+        error = { "light must be an object" };
+        return {};
+    }
+
+    Light light;
+
+    const auto anchor = objectMember(value, "anchor");
+    if (anchor) {
+        optional<PropertyValue<LightAnchorType>> convertedAnchor =
+            convert<PropertyValue<LightAnchorType>>(*anchor, error);
+
+        if (convertedAnchor) {
+            light.setAnchor(*convertedAnchor);
+        } else {
+            return {};
+        }
+    }
+
+    const auto anchorTransition = objectMember(value, "anchor-transition");
+    if (anchorTransition) {
+        optional<TransitionOptions> transition =
+            convert<TransitionOptions>(*anchorTransition, error);
+        if (transition) {
+            light.setAnchorTransition(*transition);
+        } else {
+            return {};
+        }
+    }
+
+    const auto color = objectMember(value, "color");
+    if (color) {
+        optional<PropertyValue<Color>> convertedColor =
+            convert<PropertyValue<Color>>(*color, error);
+
+        if (convertedColor) {
+            light.setColor(*convertedColor);
+        } else {
+            return {};
+        }
+    }
+
+    const auto colorTransition = objectMember(value, "color-transition");
+    if (colorTransition) {
+        optional<TransitionOptions> transition =
+            convert<TransitionOptions>(*colorTransition, error);
+        if (transition) {
+            light.setColorTransition(*transition);
+        } else {
+            return {};
+        }
+    }
+
+    const auto position = objectMember(value, "position");
+    if (position) {
+        optional<PropertyValue<Position>> convertedPosition =
+            convert<PropertyValue<Position>>(*position, error);
+
+        if (convertedPosition) {
+            light.setPosition(*convertedPosition);
+        } else {
+            return {};
+        }
+    }
+
+    const auto positionTransition = objectMember(value, "position-transition");
+    if (positionTransition) {
+        optional<TransitionOptions> transition =
+            convert<TransitionOptions>(*positionTransition, error);
+        if (transition) {
+            light.setPositionTransition(*transition);
+        } else {
+            return {};
+        }
+    }
+
+    const auto intensity = objectMember(value, "intensity");
+    if (intensity) {
+        optional<PropertyValue<float>> convertedIntensity =
+            convert<PropertyValue<float>>(*intensity, error);
+
+        if (convertedIntensity) {
+            light.setIntensity(*convertedIntensity);
+        } else {
+            return {};
+        }
+    }
+
+    const auto intensityTransition = objectMember(value, "intensity-transition");
+    if (intensityTransition) {
+        optional<TransitionOptions> transition =
+            convert<TransitionOptions>(*intensityTransition, error);
+        if (transition) {
+            light.setIntensityTransition(*transition);
+        } else {
+            return {};
+        }
+    }
+
+    return { std::move(light) };
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/make_property_setters.hpp

@@ -0,0 +1,209 @@
+#pragma once
+
+// This file is generated. Edit make_property_setters.hpp.ejs, then run `make style-code`.
+
+#include <mbgl/style/conversion/property_setter.hpp>
+
+#include <mbgl/style/layers/fill_layer.hpp>
+#include <mbgl/style/layers/line_layer.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
+#include <mbgl/style/layers/circle_layer.hpp>
+#include <mbgl/style/layers/fill_extrusion_layer.hpp>
+#include <mbgl/style/layers/raster_layer.hpp>
+#include <mbgl/style/layers/background_layer.hpp>
+
+#include <unordered_map>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+inline auto makeLayoutPropertySetters() {
+    std::unordered_map<std::string, PropertySetter> result;
+
+    result["visibility"] = &setVisibility;
+
+
+    result["line-cap"] = &setProperty<LineLayer, PropertyValue<LineCapType>, &LineLayer::setLineCap>;
+    result["line-join"] = &setProperty<LineLayer, DataDrivenPropertyValue<LineJoinType>, &LineLayer::setLineJoin>;
+    result["line-miter-limit"] = &setProperty<LineLayer, PropertyValue<float>, &LineLayer::setLineMiterLimit>;
+    result["line-round-limit"] = &setProperty<LineLayer, PropertyValue<float>, &LineLayer::setLineRoundLimit>;
+
+    result["symbol-placement"] = &setProperty<SymbolLayer, PropertyValue<SymbolPlacementType>, &SymbolLayer::setSymbolPlacement>;
+    result["symbol-spacing"] = &setProperty<SymbolLayer, PropertyValue<float>, &SymbolLayer::setSymbolSpacing>;
+    result["symbol-avoid-edges"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setSymbolAvoidEdges>;
+    result["icon-allow-overlap"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconAllowOverlap>;
+    result["icon-ignore-placement"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconIgnorePlacement>;
+    result["icon-optional"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconOptional>;
+    result["icon-rotation-alignment"] = &setProperty<SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setIconRotationAlignment>;
+    result["icon-size"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconSize>;
+    result["icon-text-fit"] = &setProperty<SymbolLayer, PropertyValue<IconTextFitType>, &SymbolLayer::setIconTextFit>;
+    result["icon-text-fit-padding"] = &setProperty<SymbolLayer, PropertyValue<std::array<float, 4>>, &SymbolLayer::setIconTextFitPadding>;
+    result["icon-image"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<std::string>, &SymbolLayer::setIconImage>;
+    result["icon-rotate"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconRotate>;
+    result["icon-padding"] = &setProperty<SymbolLayer, PropertyValue<float>, &SymbolLayer::setIconPadding>;
+    result["icon-keep-upright"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setIconKeepUpright>;
+    result["icon-offset"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<std::array<float, 2>>, &SymbolLayer::setIconOffset>;
+    result["icon-anchor"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<SymbolAnchorType>, &SymbolLayer::setIconAnchor>;
+    result["icon-pitch-alignment"] = &setProperty<SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setIconPitchAlignment>;
+    result["text-pitch-alignment"] = &setProperty<SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setTextPitchAlignment>;
+    result["text-rotation-alignment"] = &setProperty<SymbolLayer, PropertyValue<AlignmentType>, &SymbolLayer::setTextRotationAlignment>;
+    result["text-field"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<std::string>, &SymbolLayer::setTextField>;
+    result["text-font"] = &setProperty<SymbolLayer, PropertyValue<std::vector<std::string>>, &SymbolLayer::setTextFont>;
+    result["text-size"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextSize>;
+    result["text-max-width"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextMaxWidth>;
+    result["text-line-height"] = &setProperty<SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextLineHeight>;
+    result["text-letter-spacing"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextLetterSpacing>;
+    result["text-justify"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<TextJustifyType>, &SymbolLayer::setTextJustify>;
+    result["text-anchor"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<SymbolAnchorType>, &SymbolLayer::setTextAnchor>;
+    result["text-max-angle"] = &setProperty<SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextMaxAngle>;
+    result["text-rotate"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextRotate>;
+    result["text-padding"] = &setProperty<SymbolLayer, PropertyValue<float>, &SymbolLayer::setTextPadding>;
+    result["text-keep-upright"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextKeepUpright>;
+    result["text-transform"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<TextTransformType>, &SymbolLayer::setTextTransform>;
+    result["text-offset"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<std::array<float, 2>>, &SymbolLayer::setTextOffset>;
+    result["text-allow-overlap"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextAllowOverlap>;
+    result["text-ignore-placement"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextIgnorePlacement>;
+    result["text-optional"] = &setProperty<SymbolLayer, PropertyValue<bool>, &SymbolLayer::setTextOptional>;
+
+
+
+
+
+    return result;
+}
+
+inline auto makePaintPropertySetters() {
+    std::unordered_map<std::string, PropertySetter> result;
+
+    result["fill-antialias"] = &setProperty<FillLayer, PropertyValue<bool>, &FillLayer::setFillAntialias>;
+    result["fill-antialias-transition"] = &setTransition<FillLayer, &FillLayer::setFillAntialiasTransition>;
+    result["fill-opacity"] = &setProperty<FillLayer, DataDrivenPropertyValue<float>, &FillLayer::setFillOpacity>;
+    result["fill-opacity-transition"] = &setTransition<FillLayer, &FillLayer::setFillOpacityTransition>;
+    result["fill-color"] = &setProperty<FillLayer, DataDrivenPropertyValue<Color>, &FillLayer::setFillColor>;
+    result["fill-color-transition"] = &setTransition<FillLayer, &FillLayer::setFillColorTransition>;
+    result["fill-outline-color"] = &setProperty<FillLayer, DataDrivenPropertyValue<Color>, &FillLayer::setFillOutlineColor>;
+    result["fill-outline-color-transition"] = &setTransition<FillLayer, &FillLayer::setFillOutlineColorTransition>;
+    result["fill-translate"] = &setProperty<FillLayer, PropertyValue<std::array<float, 2>>, &FillLayer::setFillTranslate>;
+    result["fill-translate-transition"] = &setTransition<FillLayer, &FillLayer::setFillTranslateTransition>;
+    result["fill-translate-anchor"] = &setProperty<FillLayer, PropertyValue<TranslateAnchorType>, &FillLayer::setFillTranslateAnchor>;
+    result["fill-translate-anchor-transition"] = &setTransition<FillLayer, &FillLayer::setFillTranslateAnchorTransition>;
+    result["fill-pattern"] = &setProperty<FillLayer, PropertyValue<std::string>, &FillLayer::setFillPattern>;
+    result["fill-pattern-transition"] = &setTransition<FillLayer, &FillLayer::setFillPatternTransition>;
+
+    result["line-opacity"] = &setProperty<LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineOpacity>;
+    result["line-opacity-transition"] = &setTransition<LineLayer, &LineLayer::setLineOpacityTransition>;
+    result["line-color"] = &setProperty<LineLayer, DataDrivenPropertyValue<Color>, &LineLayer::setLineColor>;
+    result["line-color-transition"] = &setTransition<LineLayer, &LineLayer::setLineColorTransition>;
+    result["line-translate"] = &setProperty<LineLayer, PropertyValue<std::array<float, 2>>, &LineLayer::setLineTranslate>;
+    result["line-translate-transition"] = &setTransition<LineLayer, &LineLayer::setLineTranslateTransition>;
+    result["line-translate-anchor"] = &setProperty<LineLayer, PropertyValue<TranslateAnchorType>, &LineLayer::setLineTranslateAnchor>;
+    result["line-translate-anchor-transition"] = &setTransition<LineLayer, &LineLayer::setLineTranslateAnchorTransition>;
+    result["line-width"] = &setProperty<LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineWidth>;
+    result["line-width-transition"] = &setTransition<LineLayer, &LineLayer::setLineWidthTransition>;
+    result["line-gap-width"] = &setProperty<LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineGapWidth>;
+    result["line-gap-width-transition"] = &setTransition<LineLayer, &LineLayer::setLineGapWidthTransition>;
+    result["line-offset"] = &setProperty<LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineOffset>;
+    result["line-offset-transition"] = &setTransition<LineLayer, &LineLayer::setLineOffsetTransition>;
+    result["line-blur"] = &setProperty<LineLayer, DataDrivenPropertyValue<float>, &LineLayer::setLineBlur>;
+    result["line-blur-transition"] = &setTransition<LineLayer, &LineLayer::setLineBlurTransition>;
+    result["line-dasharray"] = &setProperty<LineLayer, PropertyValue<std::vector<float>>, &LineLayer::setLineDasharray>;
+    result["line-dasharray-transition"] = &setTransition<LineLayer, &LineLayer::setLineDasharrayTransition>;
+    result["line-pattern"] = &setProperty<LineLayer, PropertyValue<std::string>, &LineLayer::setLinePattern>;
+    result["line-pattern-transition"] = &setTransition<LineLayer, &LineLayer::setLinePatternTransition>;
+
+    result["icon-opacity"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconOpacity>;
+    result["icon-opacity-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconOpacityTransition>;
+    result["icon-color"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setIconColor>;
+    result["icon-color-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconColorTransition>;
+    result["icon-halo-color"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setIconHaloColor>;
+    result["icon-halo-color-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconHaloColorTransition>;
+    result["icon-halo-width"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconHaloWidth>;
+    result["icon-halo-width-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconHaloWidthTransition>;
+    result["icon-halo-blur"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setIconHaloBlur>;
+    result["icon-halo-blur-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconHaloBlurTransition>;
+    result["icon-translate"] = &setProperty<SymbolLayer, PropertyValue<std::array<float, 2>>, &SymbolLayer::setIconTranslate>;
+    result["icon-translate-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconTranslateTransition>;
+    result["icon-translate-anchor"] = &setProperty<SymbolLayer, PropertyValue<TranslateAnchorType>, &SymbolLayer::setIconTranslateAnchor>;
+    result["icon-translate-anchor-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setIconTranslateAnchorTransition>;
+    result["text-opacity"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextOpacity>;
+    result["text-opacity-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextOpacityTransition>;
+    result["text-color"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setTextColor>;
+    result["text-color-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextColorTransition>;
+    result["text-halo-color"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<Color>, &SymbolLayer::setTextHaloColor>;
+    result["text-halo-color-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextHaloColorTransition>;
+    result["text-halo-width"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextHaloWidth>;
+    result["text-halo-width-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextHaloWidthTransition>;
+    result["text-halo-blur"] = &setProperty<SymbolLayer, DataDrivenPropertyValue<float>, &SymbolLayer::setTextHaloBlur>;
+    result["text-halo-blur-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextHaloBlurTransition>;
+    result["text-translate"] = &setProperty<SymbolLayer, PropertyValue<std::array<float, 2>>, &SymbolLayer::setTextTranslate>;
+    result["text-translate-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextTranslateTransition>;
+    result["text-translate-anchor"] = &setProperty<SymbolLayer, PropertyValue<TranslateAnchorType>, &SymbolLayer::setTextTranslateAnchor>;
+    result["text-translate-anchor-transition"] = &setTransition<SymbolLayer, &SymbolLayer::setTextTranslateAnchorTransition>;
+
+    result["circle-radius"] = &setProperty<CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleRadius>;
+    result["circle-radius-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleRadiusTransition>;
+    result["circle-color"] = &setProperty<CircleLayer, DataDrivenPropertyValue<Color>, &CircleLayer::setCircleColor>;
+    result["circle-color-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleColorTransition>;
+    result["circle-blur"] = &setProperty<CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleBlur>;
+    result["circle-blur-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleBlurTransition>;
+    result["circle-opacity"] = &setProperty<CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleOpacity>;
+    result["circle-opacity-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleOpacityTransition>;
+    result["circle-translate"] = &setProperty<CircleLayer, PropertyValue<std::array<float, 2>>, &CircleLayer::setCircleTranslate>;
+    result["circle-translate-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleTranslateTransition>;
+    result["circle-translate-anchor"] = &setProperty<CircleLayer, PropertyValue<TranslateAnchorType>, &CircleLayer::setCircleTranslateAnchor>;
+    result["circle-translate-anchor-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleTranslateAnchorTransition>;
+    result["circle-pitch-scale"] = &setProperty<CircleLayer, PropertyValue<CirclePitchScaleType>, &CircleLayer::setCirclePitchScale>;
+    result["circle-pitch-scale-transition"] = &setTransition<CircleLayer, &CircleLayer::setCirclePitchScaleTransition>;
+    result["circle-pitch-alignment"] = &setProperty<CircleLayer, PropertyValue<AlignmentType>, &CircleLayer::setCirclePitchAlignment>;
+    result["circle-pitch-alignment-transition"] = &setTransition<CircleLayer, &CircleLayer::setCirclePitchAlignmentTransition>;
+    result["circle-stroke-width"] = &setProperty<CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleStrokeWidth>;
+    result["circle-stroke-width-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleStrokeWidthTransition>;
+    result["circle-stroke-color"] = &setProperty<CircleLayer, DataDrivenPropertyValue<Color>, &CircleLayer::setCircleStrokeColor>;
+    result["circle-stroke-color-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleStrokeColorTransition>;
+    result["circle-stroke-opacity"] = &setProperty<CircleLayer, DataDrivenPropertyValue<float>, &CircleLayer::setCircleStrokeOpacity>;
+    result["circle-stroke-opacity-transition"] = &setTransition<CircleLayer, &CircleLayer::setCircleStrokeOpacityTransition>;
+
+    result["fill-extrusion-opacity"] = &setProperty<FillExtrusionLayer, PropertyValue<float>, &FillExtrusionLayer::setFillExtrusionOpacity>;
+    result["fill-extrusion-opacity-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionOpacityTransition>;
+    result["fill-extrusion-color"] = &setProperty<FillExtrusionLayer, DataDrivenPropertyValue<Color>, &FillExtrusionLayer::setFillExtrusionColor>;
+    result["fill-extrusion-color-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionColorTransition>;
+    result["fill-extrusion-translate"] = &setProperty<FillExtrusionLayer, PropertyValue<std::array<float, 2>>, &FillExtrusionLayer::setFillExtrusionTranslate>;
+    result["fill-extrusion-translate-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionTranslateTransition>;
+    result["fill-extrusion-translate-anchor"] = &setProperty<FillExtrusionLayer, PropertyValue<TranslateAnchorType>, &FillExtrusionLayer::setFillExtrusionTranslateAnchor>;
+    result["fill-extrusion-translate-anchor-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionTranslateAnchorTransition>;
+    result["fill-extrusion-pattern"] = &setProperty<FillExtrusionLayer, PropertyValue<std::string>, &FillExtrusionLayer::setFillExtrusionPattern>;
+    result["fill-extrusion-pattern-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionPatternTransition>;
+    result["fill-extrusion-height"] = &setProperty<FillExtrusionLayer, DataDrivenPropertyValue<float>, &FillExtrusionLayer::setFillExtrusionHeight>;
+    result["fill-extrusion-height-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionHeightTransition>;
+    result["fill-extrusion-base"] = &setProperty<FillExtrusionLayer, DataDrivenPropertyValue<float>, &FillExtrusionLayer::setFillExtrusionBase>;
+    result["fill-extrusion-base-transition"] = &setTransition<FillExtrusionLayer, &FillExtrusionLayer::setFillExtrusionBaseTransition>;
+
+    result["raster-opacity"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterOpacity>;
+    result["raster-opacity-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterOpacityTransition>;
+    result["raster-hue-rotate"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterHueRotate>;
+    result["raster-hue-rotate-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterHueRotateTransition>;
+    result["raster-brightness-min"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterBrightnessMin>;
+    result["raster-brightness-min-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterBrightnessMinTransition>;
+    result["raster-brightness-max"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterBrightnessMax>;
+    result["raster-brightness-max-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterBrightnessMaxTransition>;
+    result["raster-saturation"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterSaturation>;
+    result["raster-saturation-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterSaturationTransition>;
+    result["raster-contrast"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterContrast>;
+    result["raster-contrast-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterContrastTransition>;
+    result["raster-fade-duration"] = &setProperty<RasterLayer, PropertyValue<float>, &RasterLayer::setRasterFadeDuration>;
+    result["raster-fade-duration-transition"] = &setTransition<RasterLayer, &RasterLayer::setRasterFadeDurationTransition>;
+
+    result["background-color"] = &setProperty<BackgroundLayer, PropertyValue<Color>, &BackgroundLayer::setBackgroundColor>;
+    result["background-color-transition"] = &setTransition<BackgroundLayer, &BackgroundLayer::setBackgroundColorTransition>;
+    result["background-pattern"] = &setProperty<BackgroundLayer, PropertyValue<std::string>, &BackgroundLayer::setBackgroundPattern>;
+    result["background-pattern-transition"] = &setTransition<BackgroundLayer, &BackgroundLayer::setBackgroundPatternTransition>;
+    result["background-opacity"] = &setProperty<BackgroundLayer, PropertyValue<float>, &BackgroundLayer::setBackgroundOpacity>;
+    result["background-opacity-transition"] = &setTransition<BackgroundLayer, &BackgroundLayer::setBackgroundOpacityTransition>;
+
+    return result;
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/make_property_setters.hpp.ejs

@@ -0,0 +1,46 @@
+#pragma once
+
+// This file is generated. Edit make_property_setters.hpp.ejs, then run `make style-code`.
+
+#include <mbgl/style/conversion/property_setter.hpp>
+
+<% for (const layer of locals.layers) { -%>
+#include <mbgl/style/layers/<%- layer.type.replace('-', '_') %>_layer.hpp>
+<% } -%>
+
+#include <unordered_map>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+inline auto makeLayoutPropertySetters() {
+    std::unordered_map<std::string, PropertySetter> result;
+
+    result["visibility"] = &setVisibility;
+
+<% for (const layer of locals.layers) { -%>
+<% for (const property of layer.layoutProperties) { -%>
+    result["<%- property.name %>"] = &setProperty<<%- camelize(layer.type) %>Layer, <%- propertyValueType(property) %>, &<%- camelize(layer.type) %>Layer::set<%- camelize(property.name) %>>;
+<% } -%>
+
+<% } -%>
+    return result;
+}
+
+inline auto makePaintPropertySetters() {
+    std::unordered_map<std::string, PropertySetter> result;
+
+<% for (const layer of locals.layers) { -%>
+<% for (const property of layer.paintProperties) { -%>
+    result["<%- property.name %>"] = &setProperty<<%- camelize(layer.type) %>Layer, <%- propertyValueType(property) %>, &<%- camelize(layer.type) %>Layer::set<%- camelize(property.name) %>>;
+    result["<%- property.name %>-transition"] = &setTransition<<%- camelize(layer.type) %>Layer, &<%- camelize(layer.type) %>Layer::set<%- camelize(property.name) %>Transition>;
+<% } -%>
+
+<% } -%>
+    return result;
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/position.cpp

@@ -0,0 +1,22 @@
+#include <mbgl/style/conversion/position.hpp>
+#include <mbgl/style/conversion/constant.hpp>
+
+#include <array>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<Position> Converter<Position>::operator()(const Convertible& value, Error& error) const {
+    optional<std::array<float, 3>> spherical = convert<std::array<float, 3>>(value, error);
+
+    if (!spherical) {
+        return {};
+    }
+
+    return Position(*spherical);
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/property_setter.hpp

@@ -13,11 +13,10 @@ namespace mbgl {
 namespace style {
 namespace conversion {
 
-template <class V>
-using PropertySetter = optional<Error> (*) (Layer&, const V&);
+using PropertySetter = optional<Error> (*) (Layer&, const Convertible&);
 
-template <class V, class L, class PropertyValue, void (L::*setter)(PropertyValue)>
-optional<Error> setProperty(Layer& layer, const V& value) {
+template <class L, class PropertyValue, void (L::*setter)(PropertyValue)>
+optional<Error> setProperty(Layer& layer, const Convertible& value) {
     auto* typedLayer = layer.as<L>();
     if (!typedLayer) {
         return Error { "layer doesn't support this property" };
@@ -33,8 +32,8 @@ optional<Error> setProperty(Layer& layer, const V& value) {
     return {};
 }
 
-template <class V, class L, void (L::*setter)(const TransitionOptions&)>
-optional<Error> setTransition(Layer& layer, const V& value) {
+template <class L, void (L::*setter)(const TransitionOptions&)>
+optional<Error> setTransition(Layer& layer, const Convertible& value) {
     auto* typedLayer = layer.as<L>();
     if (!typedLayer) {
         return Error { "layer doesn't support this property" };
@@ -50,8 +49,7 @@ optional<Error> setTransition(Layer& layer, const V& value) {
     return {};
 }
 
-template <class V>
-optional<Error> setVisibility(Layer& layer, const V& value) {
+inline optional<Error> setVisibility(Layer& layer, const Convertible& value) {
     if (isUndefined(value)) {
         layer.setVisibility(VisibilityType::Visible);
         return {};

src/mbgl/style/conversion/source.cpp

@@ -0,0 +1,175 @@
+#include <mbgl/style/conversion/source.hpp>
+#include <mbgl/style/conversion/coordinate.hpp>
+#include <mbgl/style/conversion/geojson.hpp>
+#include <mbgl/style/conversion/geojson_options.hpp>
+#include <mbgl/style/conversion/tileset.hpp>
+#include <mbgl/style/sources/geojson_source.hpp>
+#include <mbgl/style/sources/raster_source.hpp>
+#include <mbgl/style/sources/vector_source.hpp>
+#include <mbgl/style/sources/image_source.hpp>
+#include <mbgl/util/geo.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+// A tile source can either specify a URL to TileJSON, or inline TileJSON.
+static optional<variant<std::string, Tileset>> convertURLOrTileset(const Convertible& value, Error& error) {
+    auto urlVal = objectMember(value, "url");
+    if (!urlVal) {
+        optional<Tileset> tileset = convert<Tileset>(value, error);
+        if (!tileset) {
+            return {};
+        }
+        return { *tileset };
+    }
+
+    optional<std::string> url = toString(*urlVal);
+    if (!url) {
+        error = { "source url must be a string" };
+        return {};
+    }
+
+    return { *url };
+}
+
+static optional<std::unique_ptr<Source>> convertRasterSource(const std::string& id,
+                                                             const Convertible& value,
+                                                             Error& error) {
+    optional<variant<std::string, Tileset>> urlOrTileset = convertURLOrTileset(value, error);
+    if (!urlOrTileset) {
+        return {};
+    }
+
+    uint16_t tileSize = util::tileSize;
+    auto tileSizeValue = objectMember(value, "tileSize");
+    if (tileSizeValue) {
+        optional<float> size = toNumber(*tileSizeValue);
+        if (!size || *size < 0 || *size > std::numeric_limits<uint16_t>::max()) {
+            error = { "invalid tileSize" };
+            return {};
+        }
+        tileSize = *size;
+    }
+
+    return { std::make_unique<RasterSource>(id, std::move(*urlOrTileset), tileSize) };
+}
+
+static optional<std::unique_ptr<Source>> convertVectorSource(const std::string& id,
+                                                             const Convertible& value,
+                                                             Error& error) {
+    optional<variant<std::string, Tileset>> urlOrTileset = convertURLOrTileset(value, error);
+    if (!urlOrTileset) {
+        return {};
+    }
+
+    return { std::make_unique<VectorSource>(id, std::move(*urlOrTileset)) };
+}
+
+static optional<std::unique_ptr<Source>> convertGeoJSONSource(const std::string& id,
+                                                              const Convertible& value,
+                                                              Error& error) {
+    auto dataValue = objectMember(value, "data");
+    if (!dataValue) {
+        error = { "GeoJSON source must have a data value" };
+        return {};
+    }
+
+    optional<GeoJSONOptions> options = convert<GeoJSONOptions>(value, error);
+    if (!options) {
+        return {};
+    }
+
+    auto result = std::make_unique<GeoJSONSource>(id, *options);
+
+    if (isObject(*dataValue)) {
+        optional<GeoJSON> geoJSON = convert<GeoJSON>(*dataValue, error);
+        if (!geoJSON) {
+            return {};
+        }
+        result->setGeoJSON(std::move(*geoJSON));
+    } else if (toString(*dataValue)) {
+        result->setURL(*toString(*dataValue));
+    } else {
+        error = { "GeoJSON data must be a URL or an object" };
+        return {};
+    }
+
+    return { std::move(result) };
+}
+
+static optional<std::unique_ptr<Source>> convertImageSource(const std::string& id,
+                                                            const Convertible& value,
+                                                            Error& error) {
+    auto urlValue = objectMember(value, "url");
+    if (!urlValue) {
+        error = { "Image source must have a url value" };
+        return {};
+    }
+    
+    auto urlString = toString(*urlValue);
+    if (!urlString) {
+        error = { "Image url must be a URL string" };
+        return {};
+    }
+    
+    auto coordinatesValue = objectMember(value, "coordinates");
+    if (!coordinatesValue) {
+        error = { "Image source must have a coordinates values" };
+        return {};
+    }
+    
+    if (!isArray(*coordinatesValue) || arrayLength(*coordinatesValue) != 4) {
+        error = { "Image coordinates must be an array of four longitude latitude pairs" };
+        return {};
+    }
+    
+    std::array<LatLng, 4> coordinates;
+    for (std::size_t i=0; i < 4; i++) {
+        auto latLng = conversion::convert<LatLng>(arrayMember(*coordinatesValue,i), error);
+        if (!latLng) {
+            return {};
+        }
+        coordinates[i] = *latLng;
+    }
+    auto result = std::make_unique<ImageSource>(id, coordinates);
+    result->setURL(*urlString);
+
+    return { std::move(result) };
+}
+
+optional<std::unique_ptr<Source>> Converter<std::unique_ptr<Source>>::operator()(const Convertible& value, Error& error, const std::string& id) const {
+    if (!isObject(value)) {
+        error = { "source must be an object" };
+        return {};
+    }
+
+    auto typeValue = objectMember(value, "type");
+    if (!typeValue) {
+        error = { "source must have a type" };
+        return {};
+    }
+
+    optional<std::string> type = toString(*typeValue);
+    if (!type) {
+        error = { "source type must be a string" };
+        return {};
+    }
+
+    if (*type == "raster") {
+        return convertRasterSource(id, value, error);
+    } else if (*type == "vector") {
+        return convertVectorSource(id, value, error);
+    } else if (*type == "geojson") {
+        return convertGeoJSONSource(id, value, error);
+    } else if (*type == "image") {
+        return convertImageSource(id, value, error);
+    } else {
+        error = { "invalid source type" };
+        return {};
+    }
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/tileset.cpp

@@ -0,0 +1,73 @@
+#include <mbgl/style/conversion/tileset.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<Tileset> Converter<Tileset>::operator()(const Convertible& value, Error& error) const {
+    Tileset result;
+
+    auto tiles = objectMember(value, "tiles");
+    if (!tiles) {
+        error = { "source must have tiles" };
+        return {};
+    }
+
+    if (!isArray(*tiles)) {
+        error = { "source tiles must be an array" };
+        return {};
+    }
+
+    for (std::size_t i = 0; i < arrayLength(*tiles); i++) {
+        optional<std::string> urlTemplate = toString(arrayMember(*tiles, i));
+        if (!urlTemplate) {
+            error = { "source tiles member must be a string" };
+            return {};
+        }
+        result.tiles.push_back(std::move(*urlTemplate));
+    }
+
+    auto schemeValue = objectMember(value, "scheme");
+    if (schemeValue) {
+        optional<std::string> scheme = toString(*schemeValue);
+        if (scheme && *scheme == "tms") {
+            result.scheme = Tileset::Scheme::TMS;
+        }
+    }
+
+    auto minzoomValue = objectMember(value, "minzoom");
+    if (minzoomValue) {
+        optional<float> minzoom = toNumber(*minzoomValue);
+        if (!minzoom || *minzoom < 0 || *minzoom > std::numeric_limits<uint8_t>::max()) {
+            error = { "invalid minzoom" };
+            return {};
+        }
+        result.zoomRange.min = *minzoom;
+    }
+
+    auto maxzoomValue = objectMember(value, "maxzoom");
+    if (maxzoomValue) {
+        optional<float> maxzoom = toNumber(*maxzoomValue);
+        if (!maxzoom || *maxzoom < 0 || *maxzoom > std::numeric_limits<uint8_t>::max()) {
+            error = { "invalid maxzoom" };
+            return {};
+        }
+        result.zoomRange.max = *maxzoom;
+    }
+
+    auto attributionValue = objectMember(value, "attribution");
+    if (attributionValue) {
+        optional<std::string> attribution = toString(*attributionValue);
+        if (!attribution) {
+            error = { "source attribution must be a string" };
+            return {};
+        }
+        result.attribution = std::move(*attribution);
+    }
+
+    return result;
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/conversion/transition_options.cpp

@@ -0,0 +1,40 @@
+#include <mbgl/style/conversion/transition_options.hpp>
+
+namespace mbgl {
+namespace style {
+namespace conversion {
+
+optional<TransitionOptions> Converter<TransitionOptions>::operator()(const Convertible& value, Error& error) const {
+    if (!isObject(value)) {
+        error = { "transition must be an object" };
+        return {};
+    }
+
+    TransitionOptions result;
+
+    auto duration = objectMember(value, "duration");
+    if (duration) {
+        auto number = toNumber(*duration);
+        if (!number) {
+            error = { "duration must be a number" };
+            return {};
+        }
+        result.duration = { std::chrono::milliseconds(int64_t(*number)) };
+    }
+
+    auto delay = objectMember(value, "delay");
+    if (delay) {
+        auto number = toNumber(*delay);
+        if (!number) {
+            error = { "delay must be a number" };
+            return {};
+        }
+        result.delay = { std::chrono::milliseconds(int64_t(*number)) };
+    }
+
+    return result;
+}
+
+} // namespace conversion
+} // namespace style
+} // namespace mbgl

src/mbgl/style/parser.cpp

@@ -1,11 +1,13 @@
 #include <mbgl/style/parser.hpp>
 #include <mbgl/style/layer_impl.hpp>
+#include <mbgl/style/layers/symbol_layer.hpp>
 #include <mbgl/style/rapidjson_conversion.hpp>
 #include <mbgl/style/conversion.hpp>
 #include <mbgl/style/conversion/coordinate.hpp>
 #include <mbgl/style/conversion/source.hpp>
 #include <mbgl/style/conversion/layer.hpp>
 #include <mbgl/style/conversion/light.hpp>
+#include <mbgl/style/conversion/transition_options.hpp>
 
 #include <mbgl/util/logging.hpp>
 #include <mbgl/util/string.hpp>
@@ -149,7 +151,7 @@ void Parser::parseSources(const JSValue& value) {
     }
 
     for (const auto& property : value.GetObject()) {
-        std::string id = *conversion::toString(property.name);
+        std::string id { property.name.GetString(), property.name.GetStringLength() };
 
         conversion::Error error;
         optional<std::unique_ptr<Source>> source =
@@ -256,7 +258,7 @@ void Parser::parseLayer(const std::string& id, const JSValue& value, std::unique
         }
 
         layer = reference->cloneRef(id);
-        conversion::setPaintProperties(*layer, value);
+        conversion::setPaintProperties(*layer, conversion::Convertible(&value));
     } else {
         conversion::Error error;
         optional<std::unique_ptr<Layer>> converted = conversion::convert<std::unique_ptr<Layer>>(value, error);

src/mbgl/style/rapidjson_conversion.hpp

@@ -1,103 +1,125 @@
 #pragma once
 
 #include <mbgl/util/rapidjson.hpp>
-#include <mbgl/util/feature.hpp>
 #include <mbgl/style/conversion.hpp>
 
+#include <mapbox/geojson.hpp>
+#include <mapbox/geojson/rapidjson.hpp>
+
 namespace mbgl {
 namespace style {
 namespace conversion {
 
-inline bool isUndefined(const JSValue& value) {
-    return value.IsNull();
-}
-
-inline bool isArray(const JSValue& value) {
-    return value.IsArray();
-}
-
-inline std::size_t arrayLength(const JSValue& value) {
-    return value.Size();
-}
-
-inline const JSValue& arrayMember(const JSValue& value, std::size_t i) {
-    return value[rapidjson::SizeType(i)];
-}
-
-inline bool isObject(const JSValue& value) {
-    return value.IsObject();
-}
-
-inline const JSValue* objectMember(const JSValue& value, const char * name) {
-    if (!value.HasMember(name)) {
-        return nullptr;
+template <>
+class ConversionTraits<const JSValue*> {
+public:
+    static bool isUndefined(const JSValue* value) {
+        return value->IsNull();
     }
-    return &value[name];
-}
 
-template <class Fn>
-optional<Error> eachMember(const JSValue& value, Fn&& fn) {
-    assert(value.IsObject());
-    for (const auto& property : value.GetObject()) {
-        optional<Error> result =
-            fn({ property.name.GetString(), property.name.GetStringLength() }, property.value);
-        if (result) {
-            return result;
+    static bool isArray(const JSValue* value) {
+        return value->IsArray();
+    }
+
+    static std::size_t arrayLength(const JSValue* value) {
+        return value->Size();
+    }
+
+    static const JSValue* arrayMember(const JSValue* value, std::size_t i) {
+        return &(*value)[rapidjson::SizeType(i)];
+    }
+
+    static bool isObject(const JSValue* value) {
+        return value->IsObject();
+    }
+
+    static optional<const JSValue*> objectMember(const JSValue* value, const char * name) {
+        if (!value->HasMember(name)) {
+            return optional<const JSValue*>();
+        }
+        const JSValue* const& member = &(*value)[name];
+        return {member};
+    }
+
+    template <class Fn>
+    static optional<Error> eachMember(const JSValue* value, Fn&& fn) {
+        assert(value->IsObject());
+        for (const auto& property : value->GetObject()) {
+            optional<Error> result =
+                fn({ property.name.GetString(), property.name.GetStringLength() }, &property.value);
+            if (result) {
+                return result;
+            }
+        }
+        return {};
+    }
+
+    static optional<bool> toBool(const JSValue* value) {
+        if (!value->IsBool()) {
+            return {};
+        }
+        return value->GetBool();
+    }
+
+    static optional<float> toNumber(const JSValue* value) {
+        if (!value->IsNumber()) {
+            return {};
+        }
+        return value->GetDouble();
+    }
+
+    static optional<double> toDouble(const JSValue* value) {
+        if (!value->IsNumber()) {
+            return {};
+        }
+        return value->GetDouble();
+    }
+
+    static optional<std::string> toString(const JSValue* value) {
+        if (!value->IsString()) {
+            return {};
+        }
+        return {{ value->GetString(), value->GetStringLength() }};
+    }
+
+    static optional<Value> toValue(const JSValue* value) {
+        switch (value->GetType()) {
+            case rapidjson::kNullType:
+            case rapidjson::kFalseType:
+                return { false };
+
+            case rapidjson::kTrueType:
+                return { true };
+
+            case rapidjson::kStringType:
+                return { std::string { value->GetString(), value->GetStringLength() } };
+
+            case rapidjson::kNumberType:
+                if (value->IsUint64()) return { value->GetUint64() };
+                if (value->IsInt64()) return { value->GetInt64() };
+                return { value->GetDouble() };
+
+            default:
+                return {};
         }
     }
-    return {};
-}
 
-inline optional<bool> toBool(const JSValue& value) {
-    if (!value.IsBool()) {
-        return {};
-    }
-    return value.GetBool();
-}
-
-inline optional<float> toNumber(const JSValue& value) {
-    if (!value.IsNumber()) {
-        return {};
-    }
-    return value.GetDouble();
-}
-
-inline optional<double> toDouble(const JSValue& value) {
-    if (!value.IsNumber()) {
-        return {};
-    }
-    return value.GetDouble();
-}
-
-inline optional<std::string> toString(const JSValue& value) {
-    if (!value.IsString()) {
-        return {};
-    }
-    return {{ value.GetString(), value.GetStringLength() }};
-}
-
-inline optional<Value> toValue(const JSValue& value) {
-    switch (value.GetType()) {
-        case rapidjson::kNullType:
-        case rapidjson::kFalseType:
-            return { false };
-
-        case rapidjson::kTrueType:
-            return { true };
-
-        case rapidjson::kStringType:
-            return { std::string { value.GetString(), value.GetStringLength() } };
-
-        case rapidjson::kNumberType:
-            if (value.IsUint64()) return { value.GetUint64() };
-            if (value.IsInt64()) return { value.GetInt64() };
-            return { value.GetDouble() };
-
-        default:
+    static optional<GeoJSON> toGeoJSON(const JSValue* value, Error& error) {
+        try {
+            return mapbox::geojson::convert(*value);
+        } catch (const std::exception& ex) {
+            error = { ex.what() };
             return {};
+        }
     }
+};
+
+template <class T, class...Args>
+optional<T> convert(const JSValue& value, Error& error, Args&&...args) {
+    return convert<T>(Convertible(&value), error, std::forward<Args>(args)...);
 }
 
 } // namespace conversion
 } // namespace style
 } // namespace mbgl
+

test/src/mbgl/test/conversion_stubs.hpp

@@ -1,124 +0,0 @@
-#pragma once
-
-#include <mbgl/style/conversion.hpp>
-#include <mbgl/util/feature.hpp>
-#include <mbgl/util/optional.hpp>
-#include <mbgl/util/variant.hpp>
-
-#include <string>
-#include <unordered_map>
-
-namespace mbgl {
-namespace style {
-namespace conversion {
-
-class Value;
-using ValueMap = std::unordered_map<std::string, Value>;
-using ValueVector = std::vector<Value>;
-class Value : public mbgl::variant<std::string,
-                                   float,
-                                   double,
-                                   bool,
-                                   mapbox::util::recursive_wrapper<ValueMap>,
-                                   mapbox::util::recursive_wrapper<ValueVector>> {
-    using variant::variant;
-};
-
-inline bool isUndefined(const Value&) {
-    // Variant is always intialized
-    return false;
-}
-
-inline bool isArray(const Value& value) {
-    return value.is<mapbox::util::recursive_wrapper<ValueVector>>();
-}
-
-inline std::size_t arrayLength(const Value& value) {
-    return value.get<mapbox::util::recursive_wrapper<ValueVector>>().get().size();
-}
-
-inline Value arrayMember(const Value& value, std::size_t i) {
-    return value.get<mapbox::util::recursive_wrapper<ValueVector>>().get()[i];
-}
-
-inline bool isObject(const Value& value) {
-    return value.is<mapbox::util::recursive_wrapper<ValueMap>>();
-}
-
-inline optional<Value> objectMember(const Value& value, const char* key) {
-    auto map = value.get<ValueMap>();
-    auto iter = map.find(key);
-
-    if (iter != map.end()) {
-        return iter->second;
-    } else {
-        return {};
-    }
-}
-
-using EachMemberFn = std::function<optional<Error>(const std::string&, const Value&)>;
-
-optional<Error> eachMember(const Value& value, EachMemberFn&& fn) {
-    auto map = value.get<ValueMap>();
-    auto iter = map.begin();
-
-    while (iter != map.end()) {
-        optional<Error> result = fn(iter->first, iter->second);
-        if (result) {
-            return result;
-        }
-
-        ++iter;
-    }
-
-    return {};
-}
-
-inline optional<bool> toBool(const Value& value) {
-    if (value.is<bool>()) {
-        return value.get<bool>();
-    } else {
-        return {};
-    }
-}
-
-inline optional<float> toNumber(const Value& value) {
-    if (value.is<float>()) {
-        return value.get<float>();
-    } else {
-        return {};
-    }
-    return {};
-}
-
-
-inline optional<double> toDouble(const Value& value) {
-    if (value.is<double>()) {
-        return value.get<double>();
-    }
-    return {};
-}
-
-inline optional<std::string> toString(const Value& value) {
-    if (value.is<std::string>()) {
-        return value.get<std::string>();
-    } else {
-        return {};
-    }
-}
-
-inline optional<mbgl::Value> toValue(const Value& value) {
-    if (value.is<bool>()) {
-        return { value.get<bool>() };
-    } else if (value.is<std::string>()) {
-        return { value.get<std::string>() };
-    } else if (value.is<float>()) {
-        return { double(value.get<float>()) };
-    } else {
-        return {};
-    }
-}
-
-} // namespace conversion
-} // namespace style
-} // namespace mbgl