Merge pull request #433 from mapbox/update-variant

Update variant implementation

include/mbgl/style/filter_expression.hpp

@@ -10,7 +10,7 @@ namespace mbgl {
 
 class FilterExpression {
 public:
-    typedef util::recursive_wrapper<FilterExpression> Wrapper;
+    typedef mapbox::util::recursive_wrapper<FilterExpression> Wrapper;
 
     enum class Operator : uint8_t {
         And,

include/mbgl/style/function_properties.hpp

@@ -27,7 +27,7 @@ private:
 };
 
 template <typename T>
-using Function = util::variant<
+using Function = mapbox::util::variant<
     std::false_type,
     ConstantFunction<T>,
     StopsFunction<T>

include/mbgl/style/property_value.hpp

@@ -7,7 +7,7 @@
 
 namespace mbgl {
 
-typedef util::variant<
+typedef mapbox::util::variant<
     std::string,
     TranslateAnchorType,
     RotateAnchorType,

include/mbgl/style/style_bucket.hpp

@@ -89,8 +89,8 @@ public:
     float buffer = 0.03125f;
 };
 
-typedef util::variant<StyleBucketFill, StyleBucketLine, StyleBucketSymbol,
-                      StyleBucketRaster, std::false_type> StyleBucketRender;
+typedef mapbox::util::variant<StyleBucketFill, StyleBucketLine, StyleBucketSymbol,
+                              StyleBucketRaster, std::false_type> StyleBucketRender;
 
 
 class StyleBucket {

include/mbgl/style/style_properties.hpp

@@ -95,7 +95,7 @@ struct BackgroundProperties {
     Color color = {{ 0, 0, 0, 1 }};
 };
 
-typedef util::variant<
+typedef mapbox::util::variant<
     FillProperties,
     LineProperties,
     SymbolProperties,

include/mbgl/style/value.hpp

@@ -9,7 +9,7 @@
 
 namespace mbgl {
 
-typedef util::variant<bool, int64_t, uint64_t, double, std::string> Value;
+typedef mapbox::util::variant<bool, int64_t, uint64_t, double, std::string> Value;
 
 std::string toString(const Value &value);
 

include/mbgl/util/recursive_wrapper.hpp

@@ -3,7 +3,7 @@
 
 #include <utility>
 
-namespace mbgl { namespace util {
+namespace mapbox { namespace util {
 
 template <typename T>
 class recursive_wrapper

include/mbgl/util/variant.hpp

@@ -35,7 +35,7 @@
 // translates to 100
 #define VARIANT_VERSION (VARIANT_MAJOR_VERSION*100000) + (VARIANT_MINOR_VERSION*100) + (VARIANT_PATCH_VERSION)
 
-namespace mbgl { namespace util { namespace detail {
+namespace mapbox { namespace util { namespace detail {
 
 static constexpr std::size_t invalid_value = std::size_t(-1);
 
@@ -487,6 +487,8 @@ private:
 
 } // namespace detail
 
+struct no_init {};
+
 template<typename... Types>
 class variant
 {
@@ -503,12 +505,16 @@ private:
 
 public:
 
+
     VARIANT_INLINE variant()
         : type_index(sizeof...(Types) - 1)
     {
         new (&data) typename detail::select_type<0, Types...>::type();
     }
 
+    VARIANT_INLINE variant(no_init)
+        : type_index(detail::invalid_value) {}
+
     template <typename T, class = typename std::enable_if<
                          detail::is_valid_type<T, Types...>::value>::type>
     VARIANT_INLINE explicit variant(T const& val) noexcept
@@ -715,11 +721,24 @@ auto VARIANT_INLINE static apply_visitor(F f, V & v0, V & v1) -> decltype(V::bin
     return V::binary_visit(v0, v1, f);
 }
 
+// getter interface
+template<typename ResultType, typename T>
+ResultType &  get(T & var)
+{
+    return var.template get<ResultType>();
+}
+
+template<typename ResultType, typename T>
+ResultType const&  get(T const& var)
+{
+    return var.template get<ResultType>();
+}
+
 
 // operator<<
-template <typename charT, typename traits, typename Variant>
+template <typename charT, typename traits, typename... Types>
 VARIANT_INLINE std::basic_ostream<charT, traits>&
-operator<< (std::basic_ostream<charT, traits>& out, Variant const& rhs)
+operator<< (std::basic_ostream<charT, traits>& out, variant<Types...> const& rhs)
 {
     detail::printer<std::basic_ostream<charT, traits>> visitor(out);
     apply_visitor(visitor, rhs);

src/style/style_layer.cpp

@@ -105,7 +105,7 @@ struct PropertyEvaluator {
     }
 
     T operator()(const Function<T> &value) const {
-        return util::apply_visitor(FunctionEvaluator<T>(z), value);
+        return mapbox::util::apply_visitor(FunctionEvaluator<T>(z), value);
     }
 
     template <typename P, typename std::enable_if<!std::is_convertible<P, T>::value, int>::type = 0>
@@ -146,11 +146,11 @@ void StyleLayer::applyStyleProperty(PropertyKey key, T &target, const float z, c
         for (AppliedClassProperty &property : applied.properties) {
             if (now >= property.end) {
                 // We overwrite the current property with the new value.
-                target = util::apply_visitor(evaluator, property.value);
+                target = mapbox::util::apply_visitor(evaluator, property.value);
             } else if (now >= property.begin) {
                 // We overwrite the current property partially with the new value.
                 float progress = float(now - property.begin) / float(property.end - property.begin);
-                target = interpolate(target, util::apply_visitor(evaluator, property.value), progress);
+                target = interpolate(target, mapbox::util::apply_visitor(evaluator, property.value), progress);
             } else {
                 // Do not apply this property because its transition hasn't begun yet.
             }