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August 10, 2018 13:17
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Go, inteface type validation (channel and pointer of empty struct)
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| package fetcher | |
| import ( | |
| "errors" | |
| "fmt" | |
| "reflect" | |
| ) | |
| func validateEmptyStructValue(v reflect.Value) error { | |
| if !v.IsValid() || v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct { | |
| return errors.New("must pass a empty struct pointer") | |
| } | |
| if !isZero(v) { | |
| return errors.New("must pass a empty struct pointer, you passed containing values") | |
| } | |
| return nil | |
| } | |
| func validateSendChannel(chrv reflect.Value) error { | |
| if !chrv.IsValid() || chrv.Kind() != reflect.Chan { | |
| typ := "nil" | |
| if chrv.IsValid() { | |
| typ = chrv.Type().String() | |
| } | |
| return fmt.Errorf(`must pass a channel which is send direction (got "%s")`, typ) | |
| } | |
| if (chrv.Type().ChanDir() & reflect.SendDir) == 0 { | |
| return errors.New(`must pass a channel which is send direction`) | |
| } | |
| return nil | |
| } | |
| func isZero(v reflect.Value) bool { | |
| switch v.Kind() { | |
| case reflect.Bool: | |
| return v.Bool() == false | |
| case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: | |
| return v.Int() == 0 | |
| case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, | |
| reflect.Uint64, reflect.Uintptr: | |
| return v.Uint() == 0 | |
| case reflect.Float32, reflect.Float64: | |
| return v.Float() == 0 | |
| case reflect.Complex64, reflect.Complex128: | |
| return v.Complex() == 0 | |
| case reflect.Ptr, reflect.Interface: | |
| return !v.IsNil() | |
| case reflect.Array: | |
| for i := 0; i < v.Len(); i++ { | |
| if !isZero(v.Index(i)) { | |
| return false | |
| } | |
| } | |
| return true | |
| case reflect.Slice, reflect.String, reflect.Map: | |
| return v.Len() == 0 | |
| case reflect.Struct: | |
| for i, n := 0, v.NumField(); i < n; i++ { | |
| if !isZero(v.Field(i)) { | |
| return false | |
| } | |
| } | |
| return true | |
| } | |
| return false | |
| } |
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