[core] Eliminate use of ClassProperties for layout

1 files changed, 38 insertions, 0 deletions

diff --git a/src/mbgl/style/layout_property.hpp b/src/mbgl/style/layout_property.hpp
new file mode 100644
index 0000000000..5f24e5b133
--- /dev/null
+++ b/src/mbgl/style/layout_property.hpp
@@ -0,0 +1,38 @@
+#ifndef MBGL_LAYOUT_PROPERTY
+#define MBGL_LAYOUT_PROPERTY
+
+#include <mbgl/style/property_parsing.hpp>
+#include <mbgl/style/function.hpp>
+
+#include <rapidjson/document.h>
+
+namespace mbgl {
+
+using JSVal = rapidjson::Value;
+
+template <typename T>
+class LayoutProperty {
+public:
+    LayoutProperty(T v) : value(v) {}
+
+    void parse(const char * name, const JSVal& layout) {
+        if (layout.HasMember(name)) {
+            parsedValue = detail::parseProperty<Function<T>>(name, layout[name]);
+        }
+    }
+
+    void calculate(const StyleCalculationParameters& parameters) {
+        if (parsedValue) {
+            value = (*parsedValue).evaluate(parameters);
+        }
+    }
+
+    operator T() const { return value; }
+
+    mapbox::util::optional<Function<T>> parsedValue;
+    T value;
+};
+
+}
+
+#endif