Unbox the filename inside the Node_Impl objects.

node.hpp

@@ -164,7 +164,7 @@ namespace Sass {
     bool is_unquoted() const;
     bool is_numeric() const;
 
-    string file_name() const;
+    string& file_name() const;
     size_t line_number() const;
     size_t size() const;
 
@@ -199,7 +199,7 @@ namespace Sass {
     // TO DO: look into using a custom allocator in the Node_Factory class
     vector<Node> children; // Can't be in the union because it has non-trivial constructors!
 
-    string* file_name;
+    string file_name;
     size_t line_number;
 
     Node::Type type;
@@ -275,7 +275,7 @@ namespace Sass {
   inline bool Node::is_unquoted() const    { return ip_->is_unquoted; }
   inline bool Node::is_numeric() const     { return ip_->is_numeric(); }
   
-  inline string Node::file_name() const   { return *(ip_->file_name); }
+  inline string& Node::file_name() const   { return ip_->file_name; }
   inline size_t  Node::line_number() const { return ip_->line_number; }
   inline size_t  Node::size() const        { return ip_->size(); }