[core] More efficient layer cloning

1 files changed, 5 insertions, 11 deletions

diff --git a/src/mbgl/style/paint_property.hpp b/src/mbgl/style/paint_property.hpp
index 710ce34a4f..f6ab430ed9 100644
--- a/src/mbgl/style/paint_property.hpp
+++ b/src/mbgl/style/paint_property.hpp
@@ -8,6 +8,7 @@
 #include <mbgl/style/style_cascade_parameters.hpp>
 #include <mbgl/style/style_calculation_parameters.hpp>
 #include <mbgl/util/interpolate.hpp>
+#include <mbgl/util/std.hpp>
 
 #include <rapidjson/document.h>
 
@@ -23,9 +24,8 @@ class PaintProperty {
 public:
     using Fn = Function<Result>;
 
-    PaintProperty(T fallbackValue_)
-        : fallbackValue(fallbackValue_),
-          value(fallbackValue_) {
+    PaintProperty(T fallbackValue)
+        : value(fallbackValue) {
         values.emplace(ClassID::Fallback, Fn(fallbackValue));
     }
 
@@ -34,14 +34,8 @@ public:
           transitions(other.transitions) {
     }
 
-    void operator=(const PaintProperty& other) {
-        values = other.values;
-        transitions = other.transitions;
-    }
-
     void parse(const char* name, const JSVal& layer) {
-        values.clear();
-        values.emplace(ClassID::Fallback, Fn(fallbackValue));
+        mbgl::util::erase_if(values, [] (const auto& p) { return p.first != ClassID::Fallback; });
 
         std::string transitionName = { name };
         transitionName += "-transition";
@@ -104,9 +98,9 @@ public:
         return cascaded->prior.operator bool();
     }
 
+    void operator=(const T& v) { values.emplace(ClassID::Default, Fn(v)); }
     operator T() const { return value; }
 
-    T fallbackValue;
     std::map<ClassID, Fn> values;
     std::map<ClassID, PropertyTransition> transitions;