custom swap

include/mapnik/feature_type_style.hpp

@@ -63,9 +63,11 @@ private:
     boost::optional<composite_mode_e> comp_op_;
     float opacity_;
     bool image_filters_inflate_;
+    friend void swap(feature_type_style& lhs, feature_type_style & rhs);
 public:
     feature_type_style();
     feature_type_style(feature_type_style const& rhs);
+    feature_type_style(feature_type_style &&) = default;
     feature_type_style& operator=(feature_type_style rhs);
 
     void add_rule(rule && rule);

src/feature_type_style.cpp

@@ -62,10 +62,22 @@ feature_type_style::feature_type_style(feature_type_style const& rhs)
 
 feature_type_style& feature_type_style::operator=(feature_type_style rhs)
 {
-    std::swap(*this, rhs);
+    swap(*this, rhs);
     return *this;
 }
 
+void swap( feature_type_style & lhs, feature_type_style & rhs)
+{
+    using std::swap;
+    std::swap(lhs.rules_, rhs.rules_);
+    std::swap(lhs.filter_mode_, rhs.filter_mode_);
+    std::swap(lhs.filters_, rhs.filters_);
+    std::swap(lhs.direct_filters_, rhs.direct_filters_);
+    std::swap(lhs.comp_op_, rhs.comp_op_);
+    std::swap(lhs.opacity_, rhs.opacity_);
+    std::swap(lhs.image_filters_inflate_, rhs.image_filters_inflate_);
+}
+
 void feature_type_style::add_rule(rule && rule)
 {
     rules_.push_back(std::move(rule));