Added the XGen::Mongo::Driver::Undefined data type (yuck)

lib/mongo.rb

@@ -2,6 +2,7 @@ require 'mongo/mongo'
 require 'mongo/objectid'
 require 'mongo/dbref'
 require 'mongo/binary'
+require 'mongo/undefined'
 require 'mongo/message'
 require 'mongo/db'
 require 'mongo/cursor'

lib/mongo/undefined.rb

@@ -0,0 +1,31 @@
+# --
+# Copyright (C) 2008-2009 10gen Inc.
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License, version 3, as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License
+# for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+# ++
+
+module XGen
+  module Mongo
+    module Driver
+
+      # A special "undefined" type to match Mongo's storage of UNKNOWN values.
+      # "UNKNOWN" comes from JavaScript.
+      #
+      # NOTE: this class does not attempt to provide ANY of the semantics an
+      # "unknown" object might need. It isn't nil, it isn't special in any
+      # way, and there isn't any singleton value.
+      class Undefined < Object; end
+
+    end
+  end
+end

lib/mongo/util/bson.rb

@@ -91,8 +91,9 @@ class BSON
         serialize_symbol_element(@buf, k, v)
       when BINARY
         serialize_binary_element(@buf, k, v)
-      when UNDEFINED, CODE_W_SCOPE
-        # UNDEFINED should never happen because Ruby has no UNDEFINED type
+      when UNDEFINED
+        serialize_undefined_element(@buf, k)
+      when CODE_W_SCOPE
         # TODO
         raise "unimplemented type #{type}"
       else
@@ -141,9 +142,12 @@ class BSON
       when DATE
         key = deserialize_cstr(@buf)
         doc[key] = deserialize_date_data(@buf)
-      when NULL, UNDEFINED
+      when NULL
         key = deserialize_cstr(@buf)
         doc[key] = nil
+      when UNDEFINED
+        key = deserialize_cstr(@buf)
+        doc[key] = XGen::Mongo::Driver::Undefined.new
       when REF
         key = deserialize_cstr(@buf)
         doc[key] = deserialize_dbref_data(@buf, key, parent)
@@ -284,6 +288,11 @@ class BSON
     buf.put_array(bytes)
   end
 
+  def serialize_undefined_element(buf, key)
+    buf.put(UNDEFINED)
+    self.class.serialize_cstr(buf, key)
+  end
+
   def serialize_boolean_element(buf, key, val)
     buf.put(BOOLEAN)
     self.class.serialize_cstr(buf, key)
@@ -402,6 +411,8 @@ class BSON
       OBJECT
     when Symbol
       SYMBOL
+    when XGen::Mongo::Driver::Undefined
+      UNDEFINED
     else
       raise "Unknown type of object: #{o.class.name}"
     end

lib/mongo/util/xml_to_ruby.rb

@@ -56,8 +56,10 @@ class XMLToRuby
       Time.at(e.text.to_f / 1000.0)
     when 'regex'
       regex_to_ruby(e.elements)
-    when 'null', 'undefined'
+    when 'null'
       nil
+    when 'undefined'
+      Undefined.new
     when 'doc'
       doc_to_ruby(e)
     else

tests/test_bson.rb

@@ -107,4 +107,11 @@ class BSONTest < Test::Unit::TestCase
     assert_equal 'binstring', doc2['bin']
   end
 
+  def test_undefined
+    doc = {'undef' => Undefined.new}
+    @b.serialize(doc)
+    doc2 = @b.deserialize
+    assert_kind_of Undefined, doc2['undef']
+  end
+
 end

tests/test_round_trip.rb

@@ -105,7 +105,7 @@ EOS
         assert_equal bson.length, bson_from_ruby.length
         assert_equal bson, bson_from_ruby
       rescue => ex
-#         File.open(File.join(dir, "#{name}_out_b.bson"), 'wb') { |f| DEBUG
+#         File.open(File.join(dir, "#{name}_out_b.bson"), 'wb') { |f| # DEBUG
 #           bson_from_ruby.each { |b| f.putc(b) }
 #         }
         raise ex