Golang Value.String方法代碼示例

func indexBytes(typ reflect.Type, value reflect.Value) (b []byte, err error) {
	switch typ.Kind() {
	case reflect.String:
		b = []byte(value.String())
	case reflect.Int:
		buf := new(bytes.Buffer)
		if err = binary.Write(buf, binary.BigEndian, value.Int()); err != nil {
			return
		}
		b = buf.Bytes()
	case reflect.Slice:
		switch typ.Elem().Kind() {
		case reflect.Uint8:
			b = value.Bytes()
		default:
			err = fmt.Errorf("%v is not an indexable type", typ)
		}
	case reflect.Bool:
		if value.Bool() {
			b = []byte{1}
		} else {
			b = []byte{0}
		}
	default:
		err = fmt.Errorf("%v is not an indexable type", typ)
		return
	}
	if len(b) == 0 {
		b = []byte{0}
	}
	return
}

// IsBytesValidation will return if a field is a parseable bytes value.
func IsBytesValidation(v *validator.Validate, topStruct reflect.Value, currentStructOrField reflect.Value, field reflect.Value, fieldType reflect.Type, fieldKind reflect.Kind, param string) bool {
	if fieldKind != reflect.String {
		// this is an issue with the code and really should be a panic
		return true
	}

	if field.String() == "" {
		return true
	}

	if hasReplTemplate(field) {
		// all bets are off
		return true
	}

	parts := bytesRe.FindStringSubmatch(strings.TrimSpace(field.String()))
	if len(parts) < 3 {
		return false
	}

	value, err := strconv.ParseUint(parts[1], 10, 0)
	if err != nil || value < 1 {
		return false
	}

	return true
}

func ClusterInstanceFalse(v *validator.Validate, topStruct reflect.Value, currentStructOrField reflect.Value, field reflect.Value, fieldType reflect.Type, fieldKind reflect.Kind, param string) bool {
	if fieldKind != reflect.String {
		return true
	}

	valueStr := field.String()
	if valueStr == "" {
		return true
	}

	if hasReplTemplate(field) {
		// all bets are off
		return true
	}

	currentContainer := getCurrentContainer(currentStructOrField)
	if currentContainer == nil {
		// this is an issue with the code and really should be a panic
		return true
	}

	cluster, err := currentContainer.Cluster.ParseBool()
	if err != nil {
		// don't worry about this here. cluster should have the "bool" validator.
		return true
	}

	if cluster {
		return false
	}

	return true
}

// for insert and update
// If already assigned, then just ignore tag
func GetValQuoteStr(val reflect.Value) (string, error) {
	switch val.Kind() {
	case reflect.Bool:
		boolStr := "N"
		if val.Bool() {
			boolStr = "Y"
		}
		return boolStr, nil
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return strconv.FormatInt(val.Int(), 10), nil
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		return strconv.FormatUint(val.Uint(), 10), nil
	case reflect.Float32, reflect.Float64:
		return strconv.FormatFloat(val.Float(), 'f', -1, 64), nil
	case reflect.String:
		return QuoteStr(val.String()), nil
	case reflect.Slice: //[]byte
		if val.Type().Elem().Name() != "uint8" {
			return "", fmt.Errorf("GetValQuoteStr> slicetype is not []byte: %v", val.Interface())
		}
		return QuoteStr(string(val.Interface().([]byte))), nil
	default:
		return "", fmt.Errorf("GetValQuoteStr> reflect.Value is not a string/int/uint/float/bool/[]byte!\nval: %v", val)
	}
	return "", nil
}

// ConfigItemWhenValidation will validate that the when element of a config item is in a valid format and references other valid, created objects.
func ConfigItemWhenValidation(v *validator.Validate, topStruct reflect.Value, currentStructOrField reflect.Value, field reflect.Value, fieldType reflect.Type, fieldKind reflect.Kind, param string) bool {
	root, ok := topStruct.Interface().(*RootConfig)
	if !ok {
		// this is an issue with the code and really should be a panic
		return true
	}

	if fieldKind != reflect.String {
		// this is an issue with the code and really should be a panic
		return true
	}

	var whenValue string

	whenValue = field.String()
	if whenValue == "" {
		return true
	}

	splitString := "="
	if strings.Contains(whenValue, "!=") {
		splitString = "!="
	}

	parts := strings.SplitN(whenValue, splitString, 2)
	if len(parts) >= 2 {
		whenValue = parts[0]
	}

	return configItemExists(whenValue, root)
}

func (this *databaseImplement) value2Interface(fieldValue reflect.Value) (interface{}, error) {
	fieldType := fieldValue.Type()
	fieldTypeKind := fieldType.Kind()
	switch fieldTypeKind {
	case reflect.Bool:
		return fieldValue.Bool(), nil
	case reflect.String:
		return fieldValue.String(), nil
	case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int:
		return fieldValue.Int(), nil
	case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint:
		return fieldValue.Uint(), nil
	case reflect.Float32, reflect.Float64:
		return fieldValue.Float(), nil
	case reflect.Struct:
		if fieldType == reflect.TypeOf(time.Time{}) {
			t := fieldValue.Interface().(time.Time)
			tf := t.Format("2006-01-02 15:04:05")
			return tf, nil
		} else {
			return nil, fmt.Errorf("Unsupported type %v", fieldType)
		}
	default:
		return nil, fmt.Errorf("Unsupported type %v", fieldType)
	}
}

func (p *printer) marshalSimple(typ reflect.Type, val reflect.Value) (string, []byte, error) {
	switch val.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return strconv.FormatInt(val.Int(), 10), nil, nil
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		return strconv.FormatUint(val.Uint(), 10), nil, nil
	case reflect.Float32, reflect.Float64:
		return strconv.FormatFloat(val.Float(), 'g', -1, val.Type().Bits()), nil, nil
	case reflect.String:
		return val.String(), nil, nil
	case reflect.Bool:
		return strconv.FormatBool(val.Bool()), nil, nil
	case reflect.Array:
		if typ.Elem().Kind() != reflect.Uint8 {
			break
		}
		// [...]byte
		var bytes []byte
		if val.CanAddr() {
			bytes = val.Slice(0, val.Len()).Bytes()
		} else {
			bytes = make([]byte, val.Len())
			reflect.Copy(reflect.ValueOf(bytes), val)
		}
		return "", bytes, nil
	case reflect.Slice:
		if typ.Elem().Kind() != reflect.Uint8 {
			break
		}
		// []byte
		return "", val.Bytes(), nil
	}
	return "", nil, &UnsupportedTypeError{typ}
}

// Validate checks whether the given value is writeable to this schema.
func (*NullSchema) Validate(v reflect.Value) bool {
	// Check if the value is something that can be null
	switch v.Kind() {
	case reflect.Interface:
		return v.IsNil()
	case reflect.Array:
		return v.Cap() == 0
	case reflect.Slice:
		return v.IsNil() || v.Cap() == 0
	case reflect.Map:
		return len(v.MapKeys()) == 0
	case reflect.String:
		return len(v.String()) == 0
	case reflect.Float32:
		// Should NaN floats be treated as null?
		return math.IsNaN(v.Float())
	case reflect.Float64:
		// Should NaN floats be treated as null?
		return math.IsNaN(v.Float())
	case reflect.Ptr:
		return v.IsNil()
	case reflect.Invalid:
		return true
	}

	// Nothing else in particular, so this should not validate?
	return false
}

// Returns the string representation of the field value
func (enc *encoder) encodeCol(fv reflect.Value, st reflect.StructTag) string {
	switch fv.Kind() {
	case reflect.String:
		return fv.String()
	case reflect.Int, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int8:
		return fmt.Sprintf("%v", fv.Int())
	case reflect.Float32:
		return encodeFloat(32, fv)
	case reflect.Float64:
		return encodeFloat(64, fv)
	case reflect.Bool:
		return encodeBool(fv.Bool(), st)
	case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint8:
		return fmt.Sprintf("%v", fv.Uint())
	case reflect.Complex64, reflect.Complex128:
		return fmt.Sprintf("%+.3g", fv.Complex())
	case reflect.Interface:
		return encodeInterface(fv, st)
	case reflect.Struct:
		return encodeInterface(fv, st)
	default:
		panic(fmt.Sprintf("Unsupported type %s", fv.Kind()))
	}

	return ""
}

func (e *Encoder) encodeScalar(av *dynamodb.AttributeValue, v reflect.Value, fieldTag tag) error {
	if v.Type() == numberType {
		s := v.String()
		if fieldTag.AsString {
			av.S = &s
		} else {
			av.N = &s
		}
		return nil
	}

	switch v.Kind() {
	case reflect.Bool:
		av.BOOL = new(bool)
		*av.BOOL = v.Bool()
	case reflect.String:
		if err := e.encodeString(av, v); err != nil {
			return err
		}
	default:
		// Fallback to encoding numbers, will return invalid type if not supported
		if err := e.encodeNumber(av, v); err != nil {
			return err
		}
		if fieldTag.AsString && av.NULL == nil && av.N != nil {
			av.S = av.N
			av.N = nil
		}
	}

	return nil
}

func encode(b []byte, rv reflect.Value) ([]byte, error) {

	switch rk := rv.Kind(); rk {

	case reflect.Bool:
		b = encodeBool(b, rv.Bool())
	case reflect.Int, reflect.Int8, reflect.Int64, reflect.Int32, reflect.Int16:
		b = encodeInt(b, rv.Int())
	case reflect.Uint8, reflect.Uint64, reflect.Uint, reflect.Uint32, reflect.Uint16:
		b = encodeInt(b, int64(rv.Uint()))
	case reflect.String:
		b = encodeString(b, rv.String())
	case reflect.Array, reflect.Slice:
		if rv.Len() == 0 && rv.Type().Elem().Kind() == reflect.Uint8 {
			b = encodeBytes(b, rv.Bytes())
		} else if rv.Index(0).Kind() == reflect.Uint8 {
			b = encodeBytes(b, rv.Bytes())
		} else {
			b = encodeArray(b, rv)
		}

	case reflect.Map:
		b = encodeMap(b, rv)

	case reflect.Struct:
		b = encodeStruct(b, rv)

	default:
		panic("no support for type")
	}

	return b, nil
}

func (w *interpolationWalker) MapElem(m, k, v reflect.Value) error {
	w.csData = k
	w.csKey = append(w.csKey, k)
	w.key = append(w.key, k.String())
	w.lastValue = v
	return nil
}

func refToVal(ref reflect.Value) Value {
	switch ref.Kind() {
	case reflect.Bool:
		return boolValue(ref.Bool())
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return intValue(ref.Int())
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
		reflect.Uint64, reflect.Uintptr:
		return intValue(ref.Uint())
	case reflect.Float32, reflect.Float64:
		return floatValue(ref.Float())
	case reflect.Complex64, reflect.Complex128:
		return complexValue(ref.Complex())
	case reflect.Array, reflect.Slice:
		return arrayValue{reflectValue(ref)}
	case reflect.Chan:
		return chanValue{reflectValue(ref)}
	case reflect.Map:
		return mapValue{reflectValue(ref)}
	case reflect.Ptr:
		return pointerValue{reflectValue(ref)}
	case reflect.String:
		return stringValue(ref.String())
	case reflect.Struct:
		return structValue{reflectValue(ref)}
	}
	return nilValue(0)
}

func plain_extract_value(name string, field reflect.Value) url.Values {
	values := make(url.Values)
	switch field.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		values.Add(name, strconv.FormatInt(field.Int(), 10))
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		values.Add(name, strconv.FormatUint(field.Uint(), 10))
	case reflect.Bool:
		values.Add(name, strconv.FormatBool(field.Bool()))
	case reflect.Struct:
		values = merge(values, plain_extract_struct(field))
	case reflect.Slice:
		for i := 0; i < field.Len(); i++ {
			sv := field.Index(i)
			values = merge(values, plain_extract_value(name, sv))
		}
	case reflect.String:
		values.Add(name, field.String())
	case reflect.Float32, reflect.Float64:
		values.Add(name, strconv.FormatFloat(field.Float(), 'f', -1, 64))
	case reflect.Ptr, reflect.Interface:
		values = merge(values, plain_extract_pointer(field))
	}
	return values
}

// toFloat64 convert all reflect.Value-s into float64.
func ToFloat64(v reflect.Value) float64 {
	if v.Kind() == reflect.Interface {
		v = v.Elem()
	}
	switch v.Kind() {
	case reflect.Float32, reflect.Float64:
		return v.Float()
	case reflect.Int16, reflect.Int8, reflect.Int, reflect.Int32, reflect.Int64:
		return float64(v.Int())
	case reflect.String:
		s := v.String()
		var f float64
		var err error
		if strings.HasPrefix(s, "0x") {
			f, err = strconv.ParseFloat(s, 64)
		} else {
			f, err = strconv.ParseFloat(s, 64)
		}
		if err == nil {
			return float64(f)
		}
	case reflect.Slice:
		// Should we grab first one?
		item1 := v.Index(0)
		u.Infof("is slice of strings?: %T", v, item1)
	default:
		u.Warnf("Cannot convert type?  %v", v.Kind())
	}
	return math.NaN()
}