Implement copy ctor/assignment for xpath_variable_set

xpath_variable_set is essentially an associative container; it's about time it
became copyable.

Implementation is slightly tricky due to out of memory handling. Both copy ctor
and assignment operator have strong exception guarantee (even if exceptions are
disabled! which translates to "roll back on allocation errors").

1 files changed, 9 insertions, 4 deletions

diff --git a/src/pugixml.hpp b/src/pugixml.hpp
index a7154f1..b8b8946 100644
--- a/src/pugixml.hpp
+++ b/src/pugixml.hpp
@@ -1075,17 +1075,22 @@ namespace pugi
 	private:
 		xpath_variable* _data[64];
 
-		// Non-copyable semantics
-		xpath_variable_set(const xpath_variable_set&);
-		xpath_variable_set& operator=(const xpath_variable_set&);
+		void _assign(const xpath_variable_set& rhs);
+		void _swap(xpath_variable_set& rhs);
+
+		xpath_variable* _find(const char_t* name) const;
 
-		xpath_variable* find(const char_t* name) const;
+		static bool _clone(xpath_variable* var, xpath_variable** out_result);
 
 	public:
 		// Default constructor/destructor
 		xpath_variable_set();
 		~xpath_variable_set();
 
+		// Copy constructor/assignment operator
+		xpath_variable_set(const xpath_variable_set& rhs);
+		xpath_variable_set& operator=(const xpath_variable_set& rhs);
+
 		// Add a new variable or get the existing one, if the types match
 		xpath_variable* add(const char_t* name, xpath_value_type type);