GODRIVER-1590 Use MarshalValue in transformValue helper (#386)

Author: Divjot Arora

mongo/errors.go

@@ -26,6 +26,9 @@ var ErrClientDisconnected = errors.New("client is disconnected")
 // ErrNilDocument is returned when a nil document is passed to a CRUD method.
 var ErrNilDocument = errors.New("document is nil")
 
+// ErrNilValue is returned when a nil value is passed to a CRUD method.
+var ErrNilValue = errors.New("value is nil")
+
 // ErrEmptySlice is returned when an empty slice is passed to a CRUD method that requires a non-empty slice.
 var ErrEmptySlice = errors.New("must provide at least one element in input slice")
 

mongo/mongo.go

@@ -430,17 +430,20 @@ func transformUpdateValue(registry *bsoncodec.Registry, update interface{}, chec
 }
 
 func transformValue(registry *bsoncodec.Registry, val interface{}) (bsoncore.Value, error) {
-	switch conv := val.(type) {
-	case string:
-		return bsoncore.Value{Type: bsontype.String, Data: bsoncore.AppendString(nil, conv)}, nil
-	default:
-		doc, err := transformBsoncoreDocument(registry, val)
-		if err != nil {
-			return bsoncore.Value{}, err
-		}
+	if registry == nil {
+		registry = bson.DefaultRegistry
+	}
+	if val == nil {
+		return bsoncore.Value{}, ErrNilValue
+	}
 
-		return bsoncore.Value{Type: bsontype.EmbeddedDocument, Data: doc}, nil
+	buf := make([]byte, 0, 256)
+	bsonType, bsonValue, err := bson.MarshalValueAppendWithRegistry(registry, buf[:0], val)
+	if err != nil {
+		return bsoncore.Value{}, MarshalError{Value: val, Err: err}
 	}
+
+	return bsoncore.Value{Type: bsonType, Data: bsonValue}, nil
 }
 
 // Build the aggregation pipeline for the CountDocument command.

mongo/mongo_test.go

@@ -274,6 +274,38 @@ func TestMongoHelpers(t *testing.T) {
 			})
 		}
 	})
+	t.Run("transform value", func(t *testing.T) {
+		valueMarshaler := bvMarsh{
+			t:    bsontype.String,
+			data: bsoncore.AppendString(nil, "foo"),
+		}
+		doc := bson.D{{"x", 1}}
+		docBytes, _ := bson.Marshal(doc)
+
+		testCases := []struct {
+			name      string
+			value     interface{}
+			err       error
+			bsonType  bsontype.Type
+			bsonValue []byte
+		}{
+			{"nil document", nil, ErrNilValue, 0, nil},
+			{"value marshaler", valueMarshaler, nil, valueMarshaler.t, valueMarshaler.data},
+			{"document", doc, nil, bsontype.EmbeddedDocument, docBytes},
+		}
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				res, err := transformValue(nil, tc.value)
+				if tc.err != nil {
+					assert.Equal(t, tc.err, err, "expected error %v, got %v", tc.err, err)
+					return
+				}
+
+				assert.Equal(t, tc.bsonType, res.Type, "expected BSON type %s, got %s", tc.bsonType, res.Type)
+				assert.Equal(t, tc.bsonValue, res.Data, "expected BSON data %v, got %v", tc.bsonValue, res.Data)
+			})
+		}
+	})
 }
 
 var _ bson.Marshaler = bMarsh{}