69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
package options
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import (
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"fmt"
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"reflect"
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"strconv"
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)
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func defaultStruct(s interface{}) error {
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val := reflect.ValueOf(s)
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var typ reflect.Type
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if val.Kind() == reflect.Ptr {
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typ = val.Elem().Type()
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} else {
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typ = val.Type()
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}
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for i := 0; i < typ.NumField(); i++ {
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field := typ.Field(i)
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fieldV := reflect.Indirect(val).Field(i)
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// If the field is a ptr, recurse
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if field.Type.Kind() == reflect.Ptr {
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if fieldV.IsNil() {
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fieldV.Set(reflect.New(fieldV.Type().Elem()))
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}
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err := defaultStruct(fieldV.Interface())
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if err != nil {
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return fmt.Errorf("error defaulting %s: %v", field.Name, err)
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}
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continue
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}
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// If the field is a ptr, recurse
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if field.Type.Kind() == reflect.Struct {
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newField := reflect.New(reflect.TypeOf(fieldV.Interface()))
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err := defaultStruct(newField.Interface())
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if err != nil {
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return fmt.Errorf("error defaulting %s: %v", field.Name, err)
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}
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fieldV.Set(newField.Elem())
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continue
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}
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defaultVal := field.Tag.Get("default")
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if defaultVal != "" {
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switch fieldV.Kind() {
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case reflect.String:
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fieldV.Set(reflect.ValueOf(defaultVal).Convert(field.Type))
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case reflect.Bool:
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boolVal, err := strconv.ParseBool(defaultVal)
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if err != nil {
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return fmt.Errorf("expected default value (%s) to be bool: %v", defaultVal, err)
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}
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fieldV.Set(reflect.ValueOf(boolVal).Convert(field.Type))
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case reflect.Int64:
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intVal, err := strconv.ParseInt(defaultVal, 10, 64)
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if err != nil {
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return fmt.Errorf("expected default value (%s) to be int: %v", defaultVal, err)
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}
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fieldV.Set(reflect.ValueOf(intVal).Convert(field.Type))
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}
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}
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}
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return nil
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}
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