Allow initializing MGLGeoJSONSource from a shape

platform/darwin/src/MGLFeature.mm

@@ -14,6 +14,7 @@
 #import "NSExpression+MGLAdditions.h"
 
 #import <mbgl/util/geometry.hpp>
+#import <mbgl/style/conversion/geojson.hpp>
 #import <mapbox/geometry/feature.hpp>
 
 @interface MGLPointFeature () <MGLFeaturePrivate>
@@ -33,7 +34,7 @@ - (NSDictionary *)geoJSONDictionary {
 }
 
 - (mbgl::Feature)mbglFeature {
-    return mbglFeature([self featureObject], identifier, self.attributes);
+    return mbglFeature({[self geometryObject]}, identifier, self.attributes);
 }
 
 @end
@@ -55,7 +56,7 @@ - (NSDictionary *)geoJSONDictionary {
 }
 
 - (mbgl::Feature)mbglFeature {
-    return mbglFeature([self featureObject], identifier, self.attributes);
+    return mbglFeature({[self geometryObject]}, identifier, self.attributes);
 }
 
 @end
@@ -77,7 +78,7 @@ - (NSDictionary *)geoJSONDictionary {
 }
 
 - (mbgl::Feature)mbglFeature {
-    return mbglFeature([self featureObject], identifier, self.attributes);
+    return mbglFeature({[self geometryObject]}, identifier, self.attributes);
 }
 
 @end
@@ -99,7 +100,7 @@ - (NSDictionary *)geoJSONDictionary {
 }
 
 - (mbgl::Feature)mbglFeature {
-    return mbglFeature([self featureObject], identifier, self.attributes);
+    return mbglFeature({[self geometryObject]}, identifier, self.attributes);
 }
 
 @end
@@ -121,7 +122,7 @@ - (NSDictionary *)geoJSONDictionary {
 }
 
 - (mbgl::Feature)mbglFeature {
-    return mbglFeature([self featureObject], identifier, self.attributes);
+    return mbglFeature({[self geometryObject]}, identifier, self.attributes);
 }
 
 @end
@@ -143,7 +144,7 @@ - (NSDictionary *)geoJSONDictionary {
 }
 
 - (mbgl::Feature)mbglFeature {
-    return mbglFeature([self featureObject], identifier, self.attributes);
+    return mbglFeature({[self geometryObject]}, identifier, self.attributes);
 }
 
 @end
@@ -266,27 +267,61 @@ static CLLocationCoordinate2D toLocationCoordinate2D(const mbgl::Point<T> &point
     }
 };
 
+template <typename T>
+class GeoJSONEvaluator {
+public:
+    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::Geometry<T> &geometry) const {
+        GeometryEvaluator<T> evaluator;
+        MGLShape <MGLFeaturePrivate> *shape = mapbox::geometry::geometry<T>::visit(geometry, evaluator);
+        return shape;
+    }
+
+    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::Feature &feature) const {
+        GeometryEvaluator<T> evaluator;
+        MGLShape <MGLFeaturePrivate> *shape = mapbox::geometry::geometry<T>::visit(feature.geometry, evaluator);
+        return shape;
+    }
+
+    MGLShape <MGLFeaturePrivate> * operator()(const mbgl::FeatureCollection &collection) const {
+        NSMutableArray *shapes = [NSMutableArray arrayWithCapacity:collection.size()];
+        for (const auto &feature : collection) {
+            [shapes addObject:MGLFeatureFromMBGLFeature(feature)];
+        }
+        return [MGLShapeCollection<MGLFeaturePrivate> shapeCollectionWithShapes:shapes];
+    }
+};
+
 NS_ARRAY_OF(MGLShape <MGLFeature> *) *MGLFeaturesFromMBGLFeatures(const std::vector<mbgl::Feature> &features) {
     NSMutableArray *shapes = [NSMutableArray arrayWithCapacity:features.size()];
     for (const auto &feature : features) {
-        NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:feature.properties.size()];
-        for (auto &pair : feature.properties) {
-            auto &value = pair.second;
-            ValueEvaluator evaluator;
-            attributes[@(pair.first.c_str())] = mbgl::Value::visit(value, evaluator);
-        }
-
-        GeometryEvaluator<double> evaluator;
-        MGLShape <MGLFeaturePrivate> *shape = mapbox::geometry::geometry<double>::visit(feature.geometry, evaluator);
-        if (feature.id) {
-            shape.identifier = mbgl::FeatureIdentifier::visit(*feature.id, ValueEvaluator());
-        }
-        shape.attributes = attributes;
-        [shapes addObject:shape];
+        [shapes addObject:MGLFeatureFromMBGLFeature(feature)];
     }
     return shapes;
 }
 
+id <MGLFeature> MGLFeatureFromMBGLFeature(const mbgl::Feature &feature) {
+    NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithCapacity:feature.properties.size()];
+    for (auto &pair : feature.properties) {
+        auto &value = pair.second;
+        ValueEvaluator evaluator;
+        attributes[@(pair.first.c_str())] = mbgl::Value::visit(value, evaluator);
+    }
+    GeometryEvaluator<double> evaluator;
+    MGLShape <MGLFeaturePrivate> *shape = mapbox::geometry::geometry<double>::visit(feature.geometry, evaluator);
+    if (feature.id) {
+        shape.identifier = mbgl::FeatureIdentifier::visit(*feature.id, ValueEvaluator());
+    }
+    shape.attributes = attributes;
+
+    return shape;
+}
+
+MGLShape* MGLShapeFromGeoJSON(const mapbox::geojson::geojson &geojson) {
+    GeoJSONEvaluator<double> evaluator;
+    MGLShape *shape = mapbox::geojson::geojson::visit(geojson, evaluator);
+    return shape;
+}
+
 mbgl::Feature mbglFeature(mbgl::Feature feature, id identifier, NSDictionary *attributes)
 {
     if (identifier) {

platform/darwin/src/MGLFeature_Private.h

@@ -3,6 +3,7 @@
 
 #import <mbgl/util/geo.hpp>
 #import <mbgl/util/feature.hpp>
+#import <mbgl/style/conversion/geojson.hpp>
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -12,6 +13,17 @@ NS_ASSUME_NONNULL_BEGIN
  */
 NS_ARRAY_OF(MGLShape <MGLFeature> *) *MGLFeaturesFromMBGLFeatures(const std::vector<mbgl::Feature> &features);
 
+/**
+ Returns an `MGLFeature` object converted from the given mbgl::Feature
+ */
+id <MGLFeature> MGLFeatureFromMBGLFeature(const mbgl::Feature &feature);
+
+/**
+ Returns an `MGLShape` representing the given geojson. The shape can be
+ a feature, a collection of features, or a geometry.
+ */
+MGLShape* MGLShapeFromGeoJSON(const mapbox::geojson::geojson &geojson);
+
 /**
  Takes an `mbgl::Feature` object, an identifer, and attributes dictionary and
  returns the feature object with converted `mbgl::FeatureIdentifier` and 

platform/darwin/src/MGLGeoJSONSource.h

@@ -1,6 +1,7 @@
 #import "MGLSource.h"
 
 #import "MGLTypes.h"
+#import "MGLShape.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -93,28 +94,29 @@ extern const MGLGeoJSONSourceOption MGLGeoJSONSourceOptionSimplificationToleranc
 - (instancetype)initWithIdentifier:(NSString *)identifier URL:(NSURL *)url options:(nullable NS_DICTIONARY_OF(MGLGeoJSONSourceOption, id) *)options NS_DESIGNATED_INITIALIZER;
 
 /**
- Returns a GeoJSON source with an identifier, features dictionary, and dictionary 
+ Returns a GeoJSON source with an identifier, features dictionary, and dictionary
  of options for the source according to the
  <a href="https://www.mapbox.com/mapbox-gl-style-spec/#sources-geojson">style
  specification</a>.
 
  @param identifier A string that uniquely identifies the source.
- @param features An array of features that conform to the `MGLFeature` protocol.
+ @param shape A concrete subclass of `MGLShape`
  @param options An `NSDictionary` of options for this source.
  @return An initialized GeoJSON source.
  */
-- (instancetype)initWithIdentifier:(NSString *)identifier features:(NSArray<id<MGLFeature>> *)features options:(nullable NS_DICTIONARY_OF(MGLGeoJSONSourceOption, id) *)options NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithIdentifier:(NSString *)identifier shape:(nullable MGLShape *)shape options:(nullable NS_DICTIONARY_OF(MGLGeoJSONSourceOption, id) *)options NS_DESIGNATED_INITIALIZER;
 
 #pragma mark Accessing a Source’s Content
 
 /**
- The contents of the source.
+ The contents of the source. A shape can represent a GeoJSON geometry, a feature, 
+ or a collection of features.
 
  If the receiver was initialized using `-initWithIdentifier:URL:options:`, this property
  is set to `nil`. This property is unavailable until the receiver is passed into
  `-[MGLStyle addSource]`.
  */
-@property (nonatomic, nullable) NS_ARRAY_OF(id <MGLFeature>) *features;
+@property (nonatomic, nullable) MGLShape *shape;
 
 /**
  A GeoJSON representation of the contents of the source.
@@ -138,7 +140,6 @@ extern const MGLGeoJSONSourceOption MGLGeoJSONSourceOptionSimplificationToleranc
  */
 @property (nonatomic, nullable) NSURL *URL;
 
-
 @end
 
 NS_ASSUME_NONNULL_END

platform/darwin/src/MGLGeoJSONSource.mm

@@ -3,6 +3,7 @@
 #import "MGLMapView_Private.h"
 #import "MGLSource_Private.h"
 #import "MGLFeature_Private.h"
+#import "MGLShape_Private.h"
 
 #import "NSURL+MGLAdditions.h"
 
@@ -49,13 +50,13 @@ - (instancetype)initWithIdentifier:(NSString *)identifier URL:(NSURL *)url optio
     return self;
 }
 
-- (instancetype)initWithIdentifier:(NSString *)identifier features:(NSArray<id<MGLFeature>> *)features options:(NS_DICTIONARY_OF(NSString *,id) *)options {
+- (instancetype)initWithIdentifier:(NSString *)identifier shape:(nullable MGLShape *)shape options:(NSDictionary<MGLGeoJSONSourceOption,id> *)options
+{
     if (self = [super initWithIdentifier:identifier]) {
-        _features = features;
+        _shape = shape;
         _options = options;
         [self commonInit];
     }
-
     return self;
 }
 
@@ -85,21 +86,15 @@ - (void)commonInit
     if (self.URL) {
         NSURL *url = self.URL.mgl_URLByStandardizingScheme;
         source->setURL(url.absoluteString.UTF8String);
-        _features = nil;
+        _shape = nil;
     } else if (self.geoJSONData) {
         NSString *string = [[NSString alloc] initWithData:self.geoJSONData encoding:NSUTF8StringEncoding];
-        const auto geojson = mapbox::geojson::parse(string.UTF8String).get<mapbox::geojson::feature_collection>();
+        const auto geojson = mapbox::geojson::parse(string.UTF8String);
         source->setGeoJSON(geojson);
-        _features = MGLFeaturesFromMBGLFeatures(geojson);
+        _shape = MGLShapeFromGeoJSON(geojson);
     } else {
-        mbgl::FeatureCollection featureCollection;
-        featureCollection.reserve(self.features.count);
-        for (id <MGLFeaturePrivate> feature in self.features) {
-            featureCollection.push_back([feature mbglFeature]);
-        }
-        const auto geojson = mbgl::GeoJSON{featureCollection};
+        const auto geojson = mbgl::GeoJSON{self.shape.geometryObject};
         source->setGeoJSON(geojson);
-        _features = MGLFeaturesFromMBGLFeatures(featureCollection);
     }
 
     _pendingSource = std::move(source);
@@ -161,10 +156,10 @@ - (void)setGeoJSONData:(NSData *)geoJSONData
     }
 
     NSString *string = [[NSString alloc] initWithData:_geoJSONData encoding:NSUTF8StringEncoding];
-    const auto geojson = mapbox::geojson::parse(string.UTF8String).get<mapbox::geojson::feature_collection>();
+    const auto geojson = mapbox::geojson::parse(string.UTF8String);
     self.rawSource->setGeoJSON(geojson);
 
-    _features = MGLFeaturesFromMBGLFeatures(geojson);
+    _shape = MGLShapeFromGeoJSON(geojson);
 }
 
 - (void)setURL:(NSURL *)URL
@@ -180,28 +175,24 @@ - (void)setURL:(NSURL *)URL
     self.rawSource->setURL(url.absoluteString.UTF8String);
 }
 
-- (void)setFeatures:(NSArray *)features
+
+- (void)setShape:(MGLShape *)shape
 {
     if (self.rawSource == NULL)
     {
         [self commonInit];
     }
-
-    mbgl::FeatureCollection featureCollection;
-    featureCollection.reserve(features.count);
-    for (id <MGLFeaturePrivate> feature in features) {
-        featureCollection.push_back([feature mbglFeature]);
-    }
-    const auto geojson = mbgl::GeoJSON{featureCollection};
+
+    const auto geojson = mbgl::GeoJSON{shape.geometryObject};
     self.rawSource->setGeoJSON(geojson);
 
-    _features = MGLFeaturesFromMBGLFeatures(featureCollection);
+    _shape = shape;
 }
 
 - (NSString *)description
 {
-    return [NSString stringWithFormat:@"<%@: %p; identifier = %@; URL = %@; geoJSONData = %@; features = %@>",
-            NSStringFromClass([self class]), (void *)self, self.identifier, self.URL, self.geoJSONData, self.features];
+    return [NSString stringWithFormat:@"<%@: %p; identifier = %@; URL = %@; geoJSONData = %@; shape = %@>",
+            NSStringFromClass([self class]), (void *)self, self.identifier, self.URL, self.geoJSONData, self.shape];
 }
 
 @end

platform/darwin/src/MGLPointAnnotation.mm

@@ -24,10 +24,10 @@ - (NSDictionary *)geoJSONDictionary
              @"coordinates": @[@(self.coordinate.longitude), @(self.coordinate.latitude)]};
 }
 
-- (mbgl::Feature)featureObject
+- (mbgl::Geometry<double>)geometryObject
 {
     mbgl::Point<double> point = { self.coordinate.longitude, self.coordinate.latitude };
-    return mbgl::Feature {point};
+    return point;
 }
 
 @end

platform/darwin/src/MGLPointCollection.mm

@@ -71,15 +71,15 @@ - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds
     return MGLLatLngBoundsFromCoordinateBounds(_bounds).intersects(MGLLatLngBoundsFromCoordinateBounds(overlayBounds));
 }
 
-- (mbgl::Feature)featureObject
+- (mbgl::Geometry<double>)geometryObject
 {
     mbgl::MultiPoint<double> multiPoint;
     multiPoint.reserve(self.pointCount);
     for (NSInteger i = 0; i< self.pointCount; i++)
     {
         multiPoint.push_back(mbgl::Point<double>(self.coordinates[i].longitude, self.coordinates[i].latitude));
     }
-    return mbgl::Feature {multiPoint};
+    return multiPoint;
 }
 
 - (NSDictionary *)geoJSONDictionary

platform/darwin/src/MGLPolygon.mm

@@ -38,23 +38,22 @@ - (instancetype)initWithCoordinates:(const CLLocationCoordinate2D *)coords count
     return result;
 }
 
-- (mbgl::Feature)featureObject {
+- (mbgl::Polygon<double>)polygon {
     mbgl::Polygon<double> geometry;
     geometry.push_back(self.ring);
     for (MGLPolygon *polygon in self.interiorPolygons) {
         geometry.push_back(polygon.ring);
     }
-    return mbgl::Feature{geometry};
+    return geometry;
 }
 
-- (mbgl::Annotation)annotationObjectWithDelegate:(id <MGLMultiPointDelegate>)delegate {
-    mbgl::Polygon<double> geometry;
-    geometry.push_back(self.ring);
-    for (MGLPolygon *polygon in self.interiorPolygons) {
-        geometry.push_back(polygon.ring);
-    }
+- (mbgl::Geometry<double>)geometryObject {
+    return [self polygon];
+}
 
-    mbgl::FillAnnotation annotation { geometry };
+- (mbgl::Annotation)annotationObjectWithDelegate:(id <MGLMultiPointDelegate>)delegate {
+
+    mbgl::FillAnnotation annotation { [self polygon] };
     annotation.opacity = { static_cast<float>([delegate alphaForShapeAnnotation:self]) };
     annotation.outlineColor = { [delegate strokeColorForShapeAnnotation:self] };
     annotation.color = { [delegate fillColorForPolygonAnnotation:self] };
@@ -103,7 +102,7 @@ - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds {
     return MGLLatLngBoundsFromCoordinateBounds(_overlayBounds).intersects(MGLLatLngBoundsFromCoordinateBounds(overlayBounds));
 }
 
-- (mbgl::Feature)featureObject {
+- (mbgl::Geometry<double>)geometryObject {
     mbgl::MultiPolygon<double> multiPolygon;
     multiPolygon.reserve(self.polygons.count);
     for (MGLPolygon *polygon in self.polygons) {
@@ -114,7 +113,7 @@ - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds {
         }
         multiPolygon.push_back(geometry);
     }
-    return mbgl::Feature {multiPolygon};
+    return multiPolygon;
 }
 
 - (NSDictionary *)geoJSONDictionary {