[core] Replace MapChange enum with MapObserver

4 files changed, 23 insertions, 39 deletions

diff --git a/src/mbgl/map/backend.cpp b/src/mbgl/map/backend.cpp
index 8a06fe2d91..2a171cdb76 100644
--- a/src/mbgl/map/backend.cpp
+++ b/src/mbgl/map/backend.cpp
@@ -14,9 +14,4 @@ gl::Context& Backend::getContext() {
 
 Backend::~Backend() = default;
 
-void Backend::notifyMapChange(MapChange) {
-    // no-op
-}
-
-
 } // namespace mbgl
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index f4e994c931..a006571892 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -70,6 +70,7 @@ public:
     void loadStyleJSON(const std::string&);
 
     Map& map;
+    MapObserver& observer;
     Backend& backend;
     FileSource& fileSource;
     Scheduler& scheduler;
@@ -134,10 +135,11 @@ 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 +266,10 @@ 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 +284,16 @@ 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 +341,7 @@ void Map::setStyleURL(const std::string& url) {
 
     impl->loading = true;
 
-    impl->backend.notifyMapChange(MapChangeWillStartLoadingMap);
+    impl->observer.onWillStartLoadingMap();
 
     impl->styleRequest = nullptr;
     impl->styleURL = url;
@@ -385,7 +385,7 @@ void Map::setStyleJSON(const std::string& json) {
 
     impl->loading = true;
 
-    impl->backend.notifyMapChange(MapChangeWillStartLoadingMap);
+    impl->observer.onWillStartLoadingMap();
 
     impl->styleURL.clear();
     impl->styleJSON.clear();
@@ -1086,7 +1086,7 @@ void Map::onLowMemory() {
 }
 
 void Map::Impl::onSourceAttributionChanged(style::Source&, const std::string&) {
-    backend.notifyMapChange(MapChangeSourceDidChange);
+    observer.onSourceDidChange();
 }
 
 void Map::Impl::onUpdate(Update flags) {
@@ -1095,11 +1095,11 @@ void Map::Impl::onUpdate(Update flags) {
 }
 
 void Map::Impl::onStyleLoaded() {
-    backend.notifyMapChange(MapChangeDidFinishLoadingStyle);
+    observer.onDidFinishLoadingStyle();
 }
 
 void Map::Impl::onStyleError() {
-    backend.notifyMapChange(MapChangeDidFailLoadingMap);
+    observer.onDidFailLoadingMap();
 }
 
 void Map::Impl::onResourceError(std::exception_ptr error) {
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index eab9e97bc0..d325271388 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -37,10 +37,10 @@ static double _normalizeAngle(double angle, double anchorAngle)
     return angle;
 }
 
-Transform::Transform(std::function<void(MapChange)> callback_,
+Transform::Transform(MapObserver& observer_,
                      ConstrainMode constrainMode,
                      ViewportMode viewportMode)
-    : callback(std::move(callback_)), state(constrainMode, viewportMode) {
+    : observer(observer_), state(constrainMode, viewportMode) {
 }
 
 #pragma mark - Map View
@@ -50,16 +50,12 @@ bool Transform::resize(const Size size) {
         return false;
     }
 
-    if (callback) {
-        callback(MapChangeRegionWillChange);
-    }
+    observer.onCameraWillChange(MapObserver::CameraChangeMode::Immediate);
 
     state.size = size;
     state.constrain(state.scale, state.x, state.y);
 
-    if (callback) {
-        callback(MapChangeRegionDidChange);
-    }
+    observer.onCameraDidChange(MapObserver::CameraChangeMode::Immediate);
 
     return true;
 }
@@ -556,9 +552,7 @@ void Transform::startTransition(const CameraOptions& camera,
     }
 
     bool isAnimated = duration != Duration::zero();
-    if (callback) {
-        callback(isAnimated ? MapChangeRegionWillChangeAnimated : MapChangeRegionWillChange);
-    }
+    observer.onCameraWillChange(isAnimated ? MapObserver::CameraChangeMode::Animated : MapObserver::CameraChangeMode::Immediate);
 
     // Associate the anchor, if given, with a coordinate.
     optional<ScreenCoordinate> anchor = camera.anchor;
@@ -588,9 +582,7 @@ void Transform::startTransition(const CameraOptions& camera,
             if (animation.transitionFrameFn) {
                 animation.transitionFrameFn(t);
             }
-            if (callback) {
-                callback(MapChangeRegionIsChanging);
-            }
+            observer.onCameraIsChanging();
         } else {
             transitionFinishFn();
             transitionFinishFn = nullptr;
@@ -609,9 +601,7 @@ void Transform::startTransition(const CameraOptions& camera,
         if (animation.transitionFinishFn) {
             animation.transitionFinishFn();
         }
-        if (callback) {
-            callback(isAnimated ? MapChangeRegionDidChangeAnimated : MapChangeRegionDidChange);
-        }
+        observer.onCameraDidChange(isAnimated ? MapObserver::CameraChangeMode::Animated : MapObserver::CameraChangeMode::Immediate);
     };
 
     if (!isAnimated) {
diff --git a/src/mbgl/map/transform.hpp b/src/mbgl/map/transform.hpp
index 66c9915715..087ae8e690 100644
--- a/src/mbgl/map/transform.hpp
+++ b/src/mbgl/map/transform.hpp
@@ -1,8 +1,8 @@
 #pragma once
 
 #include <mbgl/map/camera.hpp>
+#include <mbgl/map/map_observer.hpp>
 #include <mbgl/map/mode.hpp>
-#include <mbgl/map/change.hpp>
 #include <mbgl/map/transform_state.hpp>
 #include <mbgl/map/update.hpp>
 #include <mbgl/util/chrono.hpp>
@@ -18,7 +18,7 @@ namespace mbgl {
 
 class Transform : private util::noncopyable {
 public:
-    Transform(std::function<void(MapChange)> = nullptr,
+    Transform(MapObserver& = MapObserver::nullObserver(),
               ConstrainMode = ConstrainMode::HeightOnly,
               ViewportMode = ViewportMode::Default);
 
@@ -163,8 +163,7 @@ public:
     LatLng screenCoordinateToLatLng(const ScreenCoordinate&) const;
 
 private:
-    std::function<void(MapChange)> callback;
-
+    MapObserver& observer;
     TransformState state;
 
     void startTransition(const CameraOptions&,