Merge branch 'release-boba' into masterupstream/fabian-merge-v4.0.0

# Conflicts:
#	circle.yml
#	include/mbgl/style/expression/let.hpp
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/geometry/LatLngBounds.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapKeyListener.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Projection.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Transform.java
#	platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/geometry/LatLngBoundsTest.java
#	platform/android/MapboxGLAndroidSDKTestApp/src/main/AndroidManifest.xml
#	platform/android/gradle/dependencies.gradle
#	platform/android/src/example_custom_layer.cpp
#	platform/android/src/geojson/point.cpp
#	platform/darwin/src/NSPredicate+MGLAdditions.mm
#	platform/darwin/test/MGLExpressionTests.mm
#	platform/ios/Mapbox-iOS-SDK-nightly-dynamic.podspec
#	platform/ios/Mapbox-iOS-SDK-symbols.podspec
#	platform/ios/Mapbox-iOS-SDK.podspec
#	platform/ios/app/MBXViewController.m
#	src/mbgl/renderer/layers/render_custom_layer.cpp
#	src/mbgl/style/conversion/filter.cpp
#	src/mbgl/style/expression/interpolate.cpp
#	src/mbgl/style/expression/value.cpp
#	test/style/filter.test.cpp

1 files changed, 34 insertions, 0 deletions

diff --git a/platform/android/src/style/layers/layer.cpp b/platform/android/src/style/layers/layer.cpp
index 29530879a5..6fe6e3cb29 100644
--- a/platform/android/src/style/layers/layer.cpp
+++ b/platform/android/src/style/layers/layer.cpp
@@ -25,6 +25,7 @@
 
 // C++ -> Java conversion
 #include "../conversion/property_value.hpp"
+#include <mbgl/style/filter.hpp>
 
 #include <string>
 
@@ -134,6 +135,38 @@ namespace android {
         layer.accept(SetFilterEvaluator {std::move(*converted)});
     }
 
+    struct GetFilterEvaluator {
+        mbgl::style::Filter noop(std::string layerType) {
+            Log::Warning(mbgl::Event::JNI, "%s doesn't support filter", layerType.c_str());
+            return {};
+        }
+
+        mbgl::style::Filter operator()(style::BackgroundLayer&) { return noop("BackgroundLayer"); }
+        mbgl::style::Filter operator()(style::CustomLayer&) { return noop("CustomLayer"); }
+        mbgl::style::Filter operator()(style::RasterLayer&) { return noop("RasterLayer"); }
+        mbgl::style::Filter operator()(style::HillshadeLayer&) { return noop("HillshadeLayer"); }
+
+        template <class LayerType>
+            mbgl::style::Filter operator()(LayerType& layer) {
+            return layer.getFilter();
+        }
+    };
+
+    jni::Object<gson::JsonElement> Layer::getFilter(jni::JNIEnv& env) {
+        using namespace mbgl::style;
+        using namespace mbgl::style::conversion;
+
+        Filter filter = layer.accept(GetFilterEvaluator());
+
+        jni::Object<gson::JsonElement> converted;
+        if (filter.is<ExpressionFilter>()) {
+            ExpressionFilter filterExpression = filter.get<ExpressionFilter>();
+            mbgl::Value expressionValue = filterExpression.expression.get()->serialize();
+            converted = gson::JsonElement::New(env, expressionValue);
+        }
+        return converted;
+    }
+
     struct SetSourceLayerEvaluator {
         std::string sourceLayer;
 
@@ -208,6 +241,7 @@ namespace android {
             METHOD(&Layer::setLayoutProperty, "nativeSetLayoutProperty"),
             METHOD(&Layer::setPaintProperty, "nativeSetPaintProperty"),
             METHOD(&Layer::setFilter, "nativeSetFilter"),
+            METHOD(&Layer::getFilter, "nativeGetFilter"),
             METHOD(&Layer::setSourceLayer, "nativeSetSourceLayer"),
             METHOD(&Layer::getSourceLayer, "nativeGetSourceLayer"),
             METHOD(&Layer::getMinZoom, "nativeGetMinZoom"),