1 files changed, 48 insertions, 0 deletions
diff --git a/src/mbgl/renderer/style_diff.hpp b/src/mbgl/renderer/style_diff.hpp
new file mode 100644
index 0000000000..a5b42fc662
--- /dev/null
+++ b/src/mbgl/renderer/style_diff.hpp
@@ -0,0 +1,48 @@
+#pragma once
+
+#include <mbgl/style/image_impl.hpp>
+#include <mbgl/style/source_impl.hpp>
+#include <mbgl/style/layer_impl.hpp>
+#include <mbgl/util/immutable.hpp>
+#include <mbgl/util/variant.hpp>
+
+#include <unordered_map>
+
+namespace mbgl {
+
+template <class T>
+class StyleChange {
+public:
+    T before;
+    T after;
+};
+
+template <class T>
+class StyleDifference {
+public:
+    std::unordered_map<std::string, T> added;
+    std::unordered_map<std::string, T> removed;
+    std::unordered_map<std::string, StyleChange<T>> changed;
+};
+
+using ImmutableImage = Immutable<style::Image::Impl>;
+using ImageDifference = StyleDifference<ImmutableImage>;
+
+ImageDifference diffImages(const Immutable<std::vector<ImmutableImage>>&,
+                           const Immutable<std::vector<ImmutableImage>>&);
+
+using ImmutableSource = Immutable<style::Source::Impl>;
+using SourceDifference = StyleDifference<ImmutableSource>;
+
+SourceDifference diffSources(const Immutable<std::vector<ImmutableSource>>&,
+                             const Immutable<std::vector<ImmutableSource>>&);
+
+using ImmutableLayer = Immutable<style::Layer::Impl>;
+using LayerDifference = StyleDifference<ImmutableLayer>;
+
+LayerDifference diffLayers(const Immutable<std::vector<ImmutableLayer>>&,
+                           const Immutable<std::vector<ImmutableLayer>>&);
+
+bool hasLayoutDifference(const LayerDifference&, const std::string& layerID);
+
+} // namespace mbgl