CXX-278 merge SERVER-14482 from upstream

SERVER-14482 Add ability to append RegEx into BSONArrayBuilder

Conflicts:
	src/mongo/dbtests/jsobjtests.cpp

Author: TylerBrock

src/mongo/bson/bsonobjbuilder.h

@@ -821,6 +821,11 @@ namespace mongo {
             return *this;
         }
 
+        BSONArrayBuilder& appendRegex(const StringData& regex, const StringData& options = "") {
+            _b.appendRegex(num(), regex, options);
+            return *this;
+        }
+
         BSONArrayBuilder& appendTimestamp(unsigned long long ts) {
             _b.appendTimestamp(num(), ts);
             return *this;

src/mongo/dbtests/jsobjtests.cpp

@@ -1716,17 +1716,25 @@ namespace JsobjTests {
             objb.appendUndefined(objb.numStr(i++));
             arrb.appendUndefined();
 
+            objb.appendRegex(objb.numStr(i++), "test", "imx");
+            arrb.appendRegex("test", "imx");
+
+            objb.append(objb.numStr(i++), BSONRegEx("test2", "s"));
+            arrb.append(BSONRegEx("test2", "s"));
+
             BSONObj obj = objb.obj();
             BSONArray arr = arrb.arr();
 
             ASSERT_EQUALS(obj, arr);
 
-            BSONObj o = BSON( "obj" << obj << "arr" << arr << "arr2" << BSONArray(obj) );
+            BSONObj o = BSON( "obj" << obj << "arr" << arr << "arr2" << BSONArray(obj)
+                    << "regex" << BSONRegEx("reg", "x"));
             //keyTest(o);
 
             ASSERT_EQUALS(o["obj"].type(), Object);
             ASSERT_EQUALS(o["arr"].type(), Array);
             ASSERT_EQUALS(o["arr2"].type(), Array);
+            ASSERT_EQUALS(o["regex"].type(), RegEx);
         }
     }; DBTEST_SHIM_TEST(BSONArrayBuilderTest);