[core] reload geojson source on url change

src/mbgl/style/source_observer.hpp

@@ -20,6 +20,9 @@ public:
     virtual void onSourceAttributionChanged(Source&, const std::string&) {}
     virtual void onSourceError(Source&, std::exception_ptr) {}
 
+    //Source description needs to be reloaded
+    virtual void onSourceDescriptionChanged(Source&) {}
+
     virtual void onTileChanged(Source&, const OverscaledTileID&) {}
     virtual void onTileError(Source&, const OverscaledTileID&, std::exception_ptr) {}
 };

src/mbgl/style/sources/geojson_source_impl.cpp

@@ -38,6 +38,12 @@ GeoJSONSource::Impl::~Impl() = default;
 
 void GeoJSONSource::Impl::setURL(std::string url_) {
     url = std::move(url_);
+
+    //Signal that the source description needs a reload
+    if (loaded) {
+        loaded = false;
+        observer->onSourceDescriptionChanged(base);
+    }
 }
 
 optional<std::string> GeoJSONSource::Impl::getURL() {
@@ -132,6 +138,7 @@ void GeoJSONSource::Impl::loadDescription(FileSource& fileSource) {
 
             loaded = true;
             observer->onSourceLoaded(base);
+            req.reset();
         }
     });
 }

src/mbgl/style/style.cpp

@@ -491,6 +491,13 @@ void Style::onSourceError(Source& source, std::exception_ptr error) {
     observer->onResourceError(error);
 }
 
+void Style::onSourceDescriptionChanged(Source& source) {
+    observer->onSourceDescriptionChanged(source);
+    if (!source.baseImpl->loaded) {
+	   source.baseImpl->loadDescription(fileSource);
+   } 
+}
+
 void Style::onTileChanged(Source& source, const OverscaledTileID& tileID) {
     observer->onTileChanged(source, tileID);
     observer->onUpdate(Update::Repaint);

src/mbgl/style/style.hpp

@@ -134,6 +134,7 @@ private:
     void onSourceLoaded(Source&) override;
     void onSourceAttributionChanged(Source&, const std::string&) override;
     void onSourceError(Source&, std::exception_ptr) override;
+    void onSourceDescriptionChanged(Source&) override;
     void onTileChanged(Source&, const OverscaledTileID&) override;
     void onTileError(Source&, const OverscaledTileID&, std::exception_ptr) override;
 

test/src/mbgl/test/stub_style_observer.hpp

@@ -38,6 +38,10 @@ public:
         if (sourceError) sourceError(source, error);
     }
 
+    void onSourceDescriptionChanged(Source& source) override {
+        if (sourceDescriptionChanged) sourceDescriptionChanged(source);
+    }
+
     void onTileChanged(Source& source, const OverscaledTileID& tileID) override {
         if (tileChanged) tileChanged(source, tileID);
     };
@@ -58,6 +62,7 @@ public:
     std::function<void (Source&)> sourceLoaded;
     std::function<void (Source&, std::string)> sourceAttributionChanged;
     std::function<void (Source&, std::exception_ptr)> sourceError;
+    std::function<void (Source&)> sourceDescriptionChanged;
     std::function<void (Source&, const OverscaledTileID&)> tileChanged;
     std::function<void (Source&, const OverscaledTileID&, std::exception_ptr)> tileError;
     std::function<void (std::exception_ptr)> resourceError;

test/style/source.test.cpp

@@ -381,3 +381,37 @@ TEST(Source, RasterTileAttribution) {
 
     test.run();
 }
+
+TEST(Source, GeoJSonSourceUrlUpdate) {
+    SourceTest test;
+    
+    test.fileSource.sourceResponse = [&] (const Resource& resource) {
+        EXPECT_EQ("url", resource.url);
+        Response response;
+        response.data = std::make_unique<std::string>("{\"geometry\": {\"type\": \"Point\", \"coordinates\": [1.1, 1.1]}, \"type\": \"Feature\", \"properties\": {}}");
+        return response;
+    };
+
+    test.observer.sourceDescriptionChanged = [&] (Source&) {
+        //Should be called (test will hang if it doesn't)
+		test.end();
+    };
+
+    test.observer.tileError = [&] (Source&, const OverscaledTileID&, std::exception_ptr) {
+        FAIL() << "Should never be called";
+    };
+
+    GeoJSONSource source("source");
+    source.baseImpl->setObserver(&test.observer);
+    
+	//Load initial, so the source state will be loaded=true
+	source.baseImpl->loadDescription(test.fileSource);
+	
+	//Schedule an update
+	test.loop.invoke([&] () {
+		//Update the url
+		source.setURL(std::string("http://source-url.ext"));	
+	});	
+
+    test.run();
+}