From fc2ddf3bbdd097dbb5228c35f9c91c57348094d7 Mon Sep 17 00:00:00 2001
From: Kyle Banker <kylebanker@gmail.com>
Date: Mon, 15 Feb 2010 09:47:53 -0500
Subject: [PATCH] deserialize to RegexpOfHolding only when necessary

---
 ext/cbson/cbson.c           | 11 +++++++++--
 lib/mongo/util/bson_ruby.rb |  7 ++++++-
 test/test_bson.rb           |  5 ++---
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/ext/cbson/cbson.c b/ext/cbson/cbson.c
index 8a1de48..05048eb 100644
--- a/ext/cbson/cbson.c
+++ b/ext/cbson/cbson.c
@@ -62,6 +62,7 @@ static VALUE DBRef;
 static VALUE Code;
 static VALUE MinKey;
 static VALUE MaxKey;
+static VALUE Regexp;
 static VALUE RegexpOfHolding;
 static VALUE OrderedHash;
 static VALUE InvalidName;
@@ -693,8 +694,13 @@ static VALUE get_value(const char* buffer, int* position, int type) {
             }
             argv[0] = pattern;
             argv[1] = INT2FIX(flags);
-            argv[2] = rb_str_new2(extra);
-            value = rb_class_new_instance(3, argv, RegexpOfHolding);
+            if(extra[0] == 0) {
+                value = rb_class_new_instance(2, argv, Regexp);
+            }
+            else { // Deserializing a RegexpOfHolding
+                argv[2] = rb_str_new2(extra);
+                value = rb_class_new_instance(3, argv, RegexpOfHolding);
+            }
             *position += flags_length + 1;
             break;
         }
@@ -877,6 +883,7 @@ void Init_cbson() {
     MinKey = rb_const_get(mongo, rb_intern("MinKey"));
     MaxKey = rb_const_get(mongo, rb_intern("MaxKey"));
     rb_require("mongo/types/regexp_of_holding");
+    Regexp = rb_const_get(rb_cObject, rb_intern("Regexp"));
     RegexpOfHolding = rb_const_get(mongo, rb_intern("RegexpOfHolding"));
     rb_require("mongo/exceptions");
     InvalidName = rb_const_get(mongo, rb_intern("InvalidName"));
diff --git a/lib/mongo/util/bson_ruby.rb b/lib/mongo/util/bson_ruby.rb
index f6a85f5..a28bf29 100644
--- a/lib/mongo/util/bson_ruby.rb
+++ b/lib/mongo/util/bson_ruby.rb
@@ -329,7 +329,12 @@ class BSON_RUBY
     options |= Regexp::MULTILINE if options_str.include?('m')
     options |= Regexp::EXTENDED if options_str.include?('x')
     options_str.gsub!(/[imx]/, '') # Now remove the three we understand
-    RegexpOfHolding.new(str, options, options_str)
+    if options_str == ''
+      Regexp.new(str, options)
+    else
+      warn("Use deprecated Regexp options #{options_str}; future versions of this MongoDB driver will support only i, m, and x. See deprecated class RegexpOfHolding for more info.")
+      RegexpOfHolding.new(str, options, options_str)
+    end
   end
 
   def deserialize_string_data(buf)
diff --git a/test/test_bson.rb b/test/test_bson.rb
index a0d5f4d..9413565 100644
--- a/test/test_bson.rb
+++ b/test/test_bson.rb
@@ -138,10 +138,9 @@ class BSONTest < Test::Unit::TestCase
     assert_equal doc, doc2
 
     r = doc2['doc']
-    assert_kind_of RegexpOfHolding, r
-    assert_equal '', r.extra_options_str
+    assert_kind_of Regexp, r
 
-    r.extra_options_str << 'zywcab'
+    r = RegexpOfHolding.new('st', 0, 'zywcab')
     assert_equal 'zywcab', r.extra_options_str
 
     doc = {'doc' => r}