[core, ios, android, qt] Observe style layer mutations rather than requiring SDKs to use Map::update

This paves the way for updates to filter and layout properties to trigger a source reload, without each SDK having to participate in the implementation.

1 files changed, 28 insertions, 0 deletions

diff --git a/test/src/mbgl/test/stub_layer_observer.hpp b/test/src/mbgl/test/stub_layer_observer.hpp
new file mode 100644
index 0000000000..500103055d
--- /dev/null
+++ b/test/src/mbgl/test/stub_layer_observer.hpp
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <mbgl/style/layer_observer.hpp>
+
+using namespace mbgl;
+using namespace mbgl::style;
+
+/**
+ * An implementation of style::LayerObserver that forwards all methods to dynamically-settable lambas.
+ */
+class StubLayerObserver : public style::LayerObserver {
+public:
+    void onLayerFilterChanged(Layer& layer) override {
+        if (layerFilterChanged) layerFilterChanged(layer);
+    }
+
+    void onLayerPaintPropertyChanged(Layer& layer) override {
+        if (layerPaintPropertyChanged) layerPaintPropertyChanged(layer);
+    }
+
+    void onLayerLayoutPropertyChanged(Layer& layer) override {
+        if (layerLayoutPropertyChanged) layerLayoutPropertyChanged(layer);
+    }
+
+    std::function<void (Layer&)> layerFilterChanged;
+    std::function<void (Layer&)> layerPaintPropertyChanged;
+    std::function<void (Layer&)> layerLayoutPropertyChanged;
+};