1 files changed, 24 insertions, 20 deletions

diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index f4e994c931..24ae5643ee 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -16,6 +16,7 @@
 #include <mbgl/storage/file_source.hpp>
 #include <mbgl/storage/resource.hpp>
 #include <mbgl/storage/response.hpp>
+#include <mbgl/util/exception.hpp>
 #include <mbgl/util/projection.hpp>
 #include <mbgl/util/math.hpp>
 #include <mbgl/util/exception.hpp>
@@ -58,10 +59,10 @@ public:
          ConstrainMode,
          ViewportMode);
 
-    void onSourceAttributionChanged(style::Source&, const std::string&) override;
+    void onSourceChanged(style::Source&) override;
     void onUpdate(Update) override;
     void onStyleLoaded() override;
-    void onStyleError() override;
+    void onStyleError(std::exception_ptr) override;
     void onResourceError(std::exception_ptr) override;
 
     void render(View&);
@@ -70,6 +71,7 @@ public:
     void loadStyleJSON(const std::string&);
 
     Map& map;
+    MapObserver& observer;
     Backend& backend;
     FileSource& fileSource;
     Scheduler& scheduler;
@@ -134,10 +136,11 @@ Map::Impl::Impl(Map& map_,
                 ConstrainMode constrainMode_,
                 ViewportMode viewportMode_)
     : map(map_),
+      observer(backend_),
       backend(backend_),
       fileSource(fileSource_),
       scheduler(scheduler_),
-      transform([this](MapChange change) { backend.notifyMapChange(change); },
+      transform(observer,
                 constrainMode_,
                 viewportMode_),
       mode(mode_),
@@ -264,10 +267,10 @@ void Map::Impl::render(View& view) {
 
     if (mode == MapMode::Continuous) {
         if (renderState == RenderState::Never) {
-            backend.notifyMapChange(MapChangeWillStartRenderingMap);
+            observer.onWillStartRenderingMap();
         }
 
-        backend.notifyMapChange(MapChangeWillStartRenderingFrame);
+        observer.onWillStartRenderingFrame();
 
         FrameData frameData { timePoint,
                               pixelRatio,
@@ -282,18 +285,16 @@ void Map::Impl::render(View& view) {
 
         painter->cleanup();
 
-        backend.notifyMapChange(style->isLoaded() ?
-            MapChangeDidFinishRenderingFrameFullyRendered :
-            MapChangeDidFinishRenderingFrame);
+        observer.onDidFinishRenderingFrame(style->isLoaded() ? MapObserver::RenderMode::Full : MapObserver::RenderMode::Partial);
 
         if (!style->isLoaded()) {
             renderState = RenderState::Partial;
         } else if (renderState != RenderState::Fully) {
             renderState = RenderState::Fully;
-            backend.notifyMapChange(MapChangeDidFinishRenderingMapFullyRendered);
+            observer.onDidFinishRenderingMap(MapObserver::RenderMode::Full);
             if (loading) {
                 loading = false;
-                backend.notifyMapChange(MapChangeDidFinishLoadingMap);
+                observer.onDidFinishLoadingMap();
             }
         }
 
@@ -341,7 +342,7 @@ void Map::setStyleURL(const std::string& url) {
 
     impl->loading = true;
 
-    impl->backend.notifyMapChange(MapChangeWillStartLoadingMap);
+    impl->observer.onWillStartLoadingMap();
 
     impl->styleRequest = nullptr;
     impl->styleURL = url;
@@ -364,11 +365,14 @@ void Map::setStyleURL(const std::string& url) {
         if (res.error) {
             if (res.error->reason == Response::Error::Reason::NotFound &&
                 util::mapbox::isMapboxURL(impl->styleURL)) {
-                Log::Error(Event::Setup, "style %s could not be found or is an incompatible legacy map or style", impl->styleURL.c_str());
+                const std::string message = "style " + impl->styleURL + " could not be found or is an incompatible legacy map or style";
+                Log::Error(Event::Setup, message.c_str());
+                impl->onStyleError(std::make_exception_ptr(util::NotFoundException(message)));
             } else {
-                Log::Error(Event::Setup, "loading style failed: %s", res.error->message.c_str());
+                const std::string message = "loading style failed: " + res.error->message;
+                Log::Error(Event::Setup, message.c_str());
+                impl->onStyleError(std::make_exception_ptr(util::StyleLoadException(message)));
             }
-            impl->onStyleError();
             impl->onResourceError(std::make_exception_ptr(std::runtime_error(res.error->message)));
         } else if (res.notModified || res.noContent) {
             return;
@@ -385,7 +389,7 @@ void Map::setStyleJSON(const std::string& json) {
 
     impl->loading = true;
 
-    impl->backend.notifyMapChange(MapChangeWillStartLoadingMap);
+    impl->observer.onWillStartLoadingMap();
 
     impl->styleURL.clear();
     impl->styleJSON.clear();
@@ -1085,8 +1089,8 @@ void Map::onLowMemory() {
     }
 }
 
-void Map::Impl::onSourceAttributionChanged(style::Source&, const std::string&) {
-    backend.notifyMapChange(MapChangeSourceDidChange);
+void Map::Impl::onSourceChanged(style::Source& source) {
+    observer.onSourceChanged(source);
 }
 
 void Map::Impl::onUpdate(Update flags) {
@@ -1095,11 +1099,11 @@ void Map::Impl::onUpdate(Update flags) {
 }
 
 void Map::Impl::onStyleLoaded() {
-    backend.notifyMapChange(MapChangeDidFinishLoadingStyle);
+    observer.onDidFinishLoadingStyle();
 }
 
-void Map::Impl::onStyleError() {
-    backend.notifyMapChange(MapChangeDidFailLoadingMap);
+void Map::Impl::onStyleError(std::exception_ptr error) {
+    observer.onDidFailLoadingMap(error);
 }
 
 void Map::Impl::onResourceError(std::exception_ptr error) {