100 lines
2.3 KiB
Go
100 lines
2.3 KiB
Go
package pubshards
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import (
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"context"
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"fmt"
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"reflect"
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"gorm.io/gorm/schema"
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)
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// 必须给结构体（而不是指针）实现此接口。FromString实现为静态方法
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type StringDBValuer interface {
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ToString() (string, error)
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FromString(str string) (any, error)
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}
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type StringSerializer struct {
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}
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func (StringSerializer) Scan(ctx context.Context, field *schema.Field, dst reflect.Value, dbValue interface{}) error {
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if dbValue == nil {
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fieldValue := reflect.New(field.FieldType)
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field.ReflectValueOf(ctx, dst).Set(fieldValue.Elem())
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return nil
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}
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str := ""
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switch v := dbValue.(type) {
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case []byte:
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str = string(v)
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case string:
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str = v
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default:
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return fmt.Errorf("expected []byte or string, got: %T", dbValue)
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}
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if field.FieldType.Kind() == reflect.Struct {
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val := reflect.Zero(field.FieldType)
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sv, ok := val.Interface().(StringDBValuer)
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if !ok {
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return fmt.Errorf("ref of field type %v is not StringDBValuer", field.FieldType)
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}
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v2, err := sv.FromString(str)
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if err != nil {
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return err
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}
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field.ReflectValueOf(ctx, dst).Set(reflect.ValueOf(v2))
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return nil
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}
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if field.FieldType.Kind() == reflect.Ptr {
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val := reflect.Zero(field.FieldType.Elem())
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sv, ok := val.Interface().(StringDBValuer)
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if !ok {
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return fmt.Errorf("field type %v is not StringDBValuer", field.FieldType)
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}
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v2, err := sv.FromString(str)
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if err != nil {
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return err
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}
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field.ReflectValueOf(ctx, dst).Set(reflect.ValueOf(v2))
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return nil
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}
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return fmt.Errorf("unsupported field type: %v", field.FieldType)
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}
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func (StringSerializer) Value(ctx context.Context, field *schema.Field, dst reflect.Value, fieldValue interface{}) (interface{}, error) {
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val := reflect.ValueOf(fieldValue)
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if val.Kind() == reflect.Struct {
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sv, ok := val.Interface().(StringDBValuer)
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if !ok {
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return nil, fmt.Errorf("ref of field type %v is not StringDBValuer", field.FieldType)
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}
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return sv.ToString()
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}
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if val.Kind() == reflect.Ptr {
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sv, ok := val.Elem().Interface().(StringDBValuer)
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if !ok {
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return nil, fmt.Errorf("field type %v is not StringDBValuer", field.FieldType)
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}
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return sv.ToString()
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}
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return nil, fmt.Errorf("unsupported field type: %v", field.FieldType)
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}
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func init() {
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schema.RegisterSerializer("string", StringSerializer{})
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}
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