lib/mongo/message/query_message.rb in mongo-0.0.4 vs lib/mongo/message/query_message.rb in mongo-0.1.0

@@ -16,24 +16,34 @@
           write_int(0)
           write_string("#{db_name}.#{collection_name}")
           write_int(query.number_to_skip)
           write_int(query.number_to_return)
           sel = query.selector
-          if query.order_by && query.order_by.length > 0
+          if query.contains_special_fields
             sel = OrderedHash.new
             sel['query'] = query.selector
-            sel['orderby'] = case query.order_by
-                             when String
-                               {query.order_by => 1}
-                             when Array
-                               h = OrderedHash.new
-                               query.order_by.each { |ob| h[ob] = 1 }
-                               h
-                             when Hash # Should be an ordered hash, but this message doesn't care
-                               query.order_by
-                             else
-                               raise "illegal order_by: is a #{query.order_by.class.name}, must be String, Array, Hash, or OrderedHash"
-                             end
+            if query.order_by && query.order_by.length > 0
+              sel['orderby'] = case query.order_by
+                               when String
+                                 {query.order_by => 1}
+                               when Array
+                                 h = OrderedHash.new
+                                 query.order_by.each { |ob| h[ob] = 1 }
+                                 h
+                               when Hash # Should be an ordered hash, but this message doesn't care
+                                 query.order_by
+                               else
+                                 raise "illegal order_by: is a #{query.order_by.class.name}, must be String, Array, Hash, or OrderedHash"
+                               end
+            end
+            if query.hint_fields && query.hint_fields.length > 0
+              hints = OrderedHash.new
+              query.hint_fields.each { |hf| hints[hf] = 1 }
+              sel['$hint'] = hints
+            end
+            if query.explain
+              sel['$explain'] = true
+            end
                                
           end
           write_doc(sel)
           write_doc(query.fields) if query.fields
         end