Function scanStruct

dialect/sql/scan.go:195–276

scanStruct returns the configuration for scanning a sql.Row into a struct.

(typ reflect.Type, columns []string)

// scanStruct returns the configuration for scanning a sql.Row into a struct.
func scanStruct(typ reflect.Type, columns []string) (*rowScan, error) {
	var (
		scan  = &rowScan{}
		idxs  = make([][]int, 0, typ.NumField())
		names = make(map[string][]int, typ.NumField())
	)
	for i := 0; i < typ.NumField(); i++ {
		f := typ.Field(i)
		// Skip unexported fields.
		if f.PkgPath != "" {
			continue
		}
		// Support 1-level embedding to accept types as `type T struct {ent.T; V int}`.
		if typ := f.Type; f.Anonymous && typ.Kind() == reflect.Struct {
			for j := 0; j < typ.NumField(); j++ {
				names[columnName(typ.Field(j))] = []int{i, j}
			}
			continue
		}
		names[columnName(f)] = []int{i}
	}
	for _, c := range columns {
		var idx []int
		// Normalize columns if necessary,
		// for example: COUNT(*) => count.
		switch name := strings.Split(c, "(")[0]; {
		case names[name] != nil:
			idx = names[name]
		case names[strings.ToLower(name)] != nil:
			idx = names[strings.ToLower(name)]
		default:
			return nil, fmt.Errorf("sql/scan: missing struct field for column: %s (%s)", c, name)
		}
		idxs = append(idxs, idx)
		rtype := typ.Field(idx[0]).Type
		if len(idx) > 1 {
			rtype = rtype.Field(idx[1]).Type
		}
		switch {
		// If the field is not support by the standard
		// convertAssign, assume it is a JSON field.
		case !supportsScan(rtype):
			rtype = nullJSONType
		// Create a pointer to the actual reflect
		// types to accept optional struct fields.
		case !nillable(rtype):
			rtype = reflect.PtrTo(rtype)
		}
		scan.columns = append(scan.columns, rtype)
	}
	scan.value = func(vs ...any) (reflect.Value, error) {
		st := reflect.New(typ).Elem()
		for i, v := range vs {
			rv := reflect.Indirect(reflect.ValueOf(v))
			if rv.IsNil() {
				continue
			}
			idx := idxs[i]