support case-insensitive copy

copier.go

@@ -37,9 +37,10 @@ const (
 type Option struct {
 	// setting this value to true will ignore copying zero values of all the fields, including bools, as well as a
 	// struct having all it's fields set to their zero values respectively (see IsZero() in reflect/value.go)
-	IgnoreEmpty bool
-	DeepCopy    bool
-	Converters  []TypeConverter
+	IgnoreEmpty   bool
+	CaseSensitive bool
+	DeepCopy      bool
+	Converters    []TypeConverter
 }
 
 func (opt Option) converters() map[converterPair]TypeConverter {
@@ -300,7 +301,7 @@ func copier(toValue interface{}, fromValue interface{}, opt Option) (err error)
 						break
 					}
 
-					toField := dest.FieldByName(destFieldName)
+					toField := fieldByName(dest, destFieldName, opt.CaseSensitive)
 					if toField.IsValid() {
 						if toField.CanSet() {
 							isSet, err := set(toField, fromField, opt.DeepCopy, converters)
@@ -346,7 +347,7 @@ func copier(toValue interface{}, fromValue interface{}, opt Option) (err error)
 				}
 
 				if fromMethod.IsValid() && fromMethod.Type().NumIn() == 0 && fromMethod.Type().NumOut() == 1 && !shouldIgnore(fromMethod, opt.IgnoreEmpty) {
-					if toField := dest.FieldByName(destFieldName); toField.IsValid() && toField.CanSet() {
+					if toField := fieldByName(dest, destFieldName, opt.CaseSensitive); toField.IsValid() && toField.CanSet() {
 						values := fromMethod.Call([]reflect.Value{})
 						if len(values) >= 1 {
 							set(toField, values[0], opt.DeepCopy, converters)
@@ -741,3 +742,11 @@ func driverValuer(v reflect.Value) (i driver.Valuer, ok bool) {
 	i, ok = v.Addr().Interface().(driver.Valuer)
 	return
 }
+
+func fieldByName(v reflect.Value, name string, caseSensitive bool) reflect.Value {
+	if caseSensitive {
+		return v.FieldByName(name)
+	}
+
+	return v.FieldByNameFunc(func(n string) bool { return strings.EqualFold(n, name) })
+}

copier_benchmark_test.go

@@ -29,7 +29,7 @@ func BenchmarkNamaCopy(b *testing.B) {
 	for x := 0; x < b.N; x++ {
 		employee := &Employee{
 			Name:      user.Name,
-			Nickname:  &user.Nickname,
+			NickName:  &user.Nickname,
 			Age:       int64(user.Age),
 			FakeAge:   int(*user.FakeAge),
 			DoubleAge: user.DoubleAge(),

copier_test.go

@@ -30,7 +30,7 @@ type Employee struct {
 	_User     *User
 	Name      string
 	Birthday  *time.Time
-	Nickname  *string
+	NickName  *string
 	Age       int64
 	FakeAge   int
 	EmployeID int64
@@ -48,7 +48,7 @@ func checkEmployee(employee Employee, user User, t *testing.T, testCase string)
 	if employee.Name != user.Name {
 		t.Errorf("%v: Name haven't been copied correctly.", testCase)
 	}
-	if employee.Nickname == nil || *employee.Nickname != user.Nickname {
+	if employee.NickName == nil || *employee.NickName != user.Nickname {
 		t.Errorf("%v: NickName haven't been copied correctly.", testCase)
 	}
 	if employee.Birthday == nil && user.Birthday != nil {
@@ -102,7 +102,7 @@ func TestCopySameStructWithPointerField(t *testing.T) {
 
 func checkEmployee2(employee Employee, user *User, t *testing.T, testCase string) {
 	if user == nil {
-		if employee.Name != "" || employee.Nickname != nil || employee.Birthday != nil || employee.Age != 0 ||
+		if employee.Name != "" || employee.NickName != nil || employee.Birthday != nil || employee.Age != 0 ||
 			employee.DoubleAge != 0 || employee.FakeAge != 0 || employee.SuperRule != "" || employee.Notes != nil {
 			t.Errorf("%v : employee should be empty", testCase)
 		}