v0.0.147

reflectext/primitiveStringSerializer.go

@@ -0,0 +1,88 @@
+package reflectext
+
+import (
+	"errors"
+	"fmt"
+	"gogs.mikescher.com/BlackForestBytes/goext/langext"
+	"reflect"
+)
+
+// PrimitiveStringSerializer is used to serialize primitive types (and a few more) from and to string
+// This is not really intended to be user facing, and more as a simple building block for other mechanisms
+// supports:
+//   - golang primitives (ints, uints, floats, bool, string)
+//   - type aliases
+//   - time.Time
+//   - primitive.ObjectID
+type PrimitiveStringSerializer struct{}
+
+func (pss PrimitiveStringSerializer) ValueToString(v any) (string, error) {
+
+	inType := reflect.TypeOf(v)
+
+	if inType.Kind() == reflect.Ptr && langext.IsNil(v) {
+		return "", nil
+	}
+
+	if inType.Kind() == reflect.Ptr {
+		rval1 := reflect.ValueOf(v)
+		rval2 := rval1.Elem()
+		rval3 := rval2.Interface()
+		return pss.ValueToString(rval3)
+	}
+
+	if conv, ok := primitiveSerializer[inType]; ok {
+		return conv.ToString(v)
+	}
+
+	for convType, conv := range primitiveSerializer {
+		if castV, ok := TryCastType(v, convType); ok {
+			return conv.ToString(castV)
+		}
+	}
+
+	return "", errors.New(fmt.Sprintf("failed to find a matching generic <toString> conversion fo type %T", v))
+}
+
+func (pss PrimitiveStringSerializer) ValueFromString(str string, outType reflect.Type) (any, error) {
+
+	if outType.Kind() == reflect.Ptr && str == "" {
+		return reflect.Zero(outType).Interface(), nil // = nil.(outType), nil
+	}
+
+	if outType.Kind() == reflect.Ptr {
+
+		innerValue, err := pss.ValueFromString(str, outType.Elem())
+		if err != nil {
+			return nil, err
+		}
+
+		// this weird piece of shit converts innerValue to &innerValue  (while keeping types)
+
+		rval1 := reflect.ValueOf(innerValue)
+		rval2 := rval1.Convert(outType.Elem())
+		rval3 := reflect.New(outType.Elem())
+		rval3.Elem().Set(rval2)
+		rval4 := rval3.Interface()
+
+		return rval4, nil
+	}
+
+	if conv, ok := primitiveSerializer[outType]; ok {
+		return conv.FromString(str)
+	}
+
+	emptyResultVal := reflect.Zero(outType).Interface()
+
+	for convType, conv := range primitiveSerializer {
+		if _, ok := TryCastType(emptyResultVal, convType); ok {
+			if convVal, err := conv.FromString(str); err == nil {
+				if resVal, ok := TryCastType(convVal, outType); ok {
+					return resVal, nil
+				}
+			}
+		}
+	}
+
+	return "", errors.New(fmt.Sprintf("failed to find a matching generic <toString> conversion fo type %s", outType.String()))
+}