Golang Value.Interface方法代码示例

// scan the value by fields, and set to v
func rawScanStruct(v reflect.Value, fields []string, scanner rowScaner) (err error) {
	if v.IsNil() {
		e := fmt.Sprintf("struct can not be nil, but got %#v", v.Interface())
		return errors.New(e)
	}
	dest := make([]interface{}, len(fields))
	for v.Kind() == reflect.Ptr {
		v = v.Elem()
	}

	// Loop over column names and find field in s to bind to
	// based on column name. all returned columns must match
	// a field in the s struct
	for x, fieldName := range fields {
		f := v.FieldByName(fieldName)
		if f == zeroVal {
			e := fmt.Sprintf("Scanner: No field %s in type %s",
				fieldName, v.Type())
			return errors.New(e)
		} else {
			dest[x] = f.Addr().Interface()
		}
	}

	err = scanner.Scan(dest...)
	return
}

// 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 ContainerNameUnique(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
	}

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

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

	root, ok := topStruct.Interface().(*RootConfig)
	if !ok {
		// this is an issue with the code and really should be a panic
		return true
	}

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

	container := getContainerFromName(containerName, currentContainer, root)
	if container != nil {
		return false
	}
	return true
}

func (d *commonDialect) SqlTag(value reflect.Value, size int) string {
	switch value.Kind() {
	case reflect.Bool:
		return "BOOLEAN"
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
		return "INTEGER"
	case reflect.Int64, reflect.Uint64:
		return "BIGINT"
	case reflect.Float32, reflect.Float64:
		return "FLOAT"
	case reflect.String:
		if size > 0 && size < 65532 {
			return fmt.Sprintf("VARCHAR(%d)", size)
		} else {
			return "VARCHAR(65532)"
		}
	case reflect.Struct:
		if value.Type() == timeType {
			return "TIMESTAMP"
		}
	default:
		if _, ok := value.Interface().([]byte); ok {
			if size > 0 && size < 65532 {
				return fmt.Sprintf("BINARY(%d)", size)
			} else {
				return "BINARY(65532)"
			}
		}
	}
	panic(fmt.Sprintf("invalid sql type %s (%s) for commonDialect", value.Type().Name(), value.Kind().String()))
}

func (par *parserParser) ParseValue(ctx *parseContext, valueOf reflect.Value, location int, err *Error) int {
	var v Parser
	if par.ptr {
		v = valueOf.Addr().Interface().(Parser)
	} else {
		if valueOf.Kind() == reflect.Ptr {
			valueOf = reflect.New(valueOf.Type().Elem())
		}
		v = valueOf.Interface().(Parser)
	}

	l, e := v.ParseValue(ctx.str, location)
	if e != nil {
		switch ev := e.(type) {
		case Error:
			err.Location = ev.Location
			err.Message = ev.Message
			err.Str = ev.Str
			return -1
		}
		err.Location = location
		err.Message = e.Error()
		return -1
	}

	location = l
	if location > len(ctx.str) {
		panic("Invalid parser")
	}

	return location
}

func (mssql) SqlTag(value reflect.Value, size int, autoIncrease bool) string {
	switch value.Kind() {
	case reflect.Bool:
		return "bit"
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
		if autoIncrease {
			return "int IDENTITY(1,1)"
		}
		return "int"
	case reflect.Int64, reflect.Uint64:
		if autoIncrease {
			return "bigint IDENTITY(1,1)"
		}
		return "bigint"
	case reflect.Float32, reflect.Float64:
		return "float"
	case reflect.String:
		if size > 0 && size < 65532 {
			return fmt.Sprintf("nvarchar(%d)", size)
		}
		return "text"
	case reflect.Struct:
		if _, ok := value.Interface().(time.Time); ok {
			return "datetime2"
		}
	default:
		if _, ok := value.Interface().([]byte); ok {
			if size > 0 && size < 65532 {
				return fmt.Sprintf("varchar(%d)", size)
			}
			return "text"
		}
	}
	panic(fmt.Sprintf("invalid sql type %s (%s) for mssql", value.Type().Name(), value.Kind().String()))
}

// IsZero returns true when the value is a zero for the type
func isZero(data reflect.Value) bool {
	if !data.CanInterface() {
		return true
	}
	tpe := data.Type()
	return reflect.DeepEqual(data.Interface(), reflect.Zero(tpe).Interface())
}

func (d base) setModelValue(driverValue, fieldValue reflect.Value) error {
	switch fieldValue.Type().Kind() {
	case reflect.Bool:
		fieldValue.SetBool(d.dialect.parseBool(driverValue.Elem()))
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		fieldValue.SetInt(driverValue.Elem().Int())
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		// reading uint from int value causes panic
		switch driverValue.Elem().Kind() {
		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
			fieldValue.SetUint(uint64(driverValue.Elem().Int()))
		default:
			fieldValue.SetUint(driverValue.Elem().Uint())
		}
	case reflect.Float32, reflect.Float64:
		fieldValue.SetFloat(driverValue.Elem().Float())
	case reflect.String:
		fieldValue.SetString(string(driverValue.Elem().Bytes()))
	case reflect.Slice:
		if reflect.TypeOf(driverValue.Interface()).Elem().Kind() == reflect.Uint8 {
			fieldValue.SetBytes(driverValue.Elem().Bytes())
		}
	case reflect.Struct:
		switch fieldValue.Interface().(type) {
		case time.Time:
			fieldValue.Set(driverValue.Elem())
		default:
			if scanner, ok := fieldValue.Addr().Interface().(sql.Scanner); ok {
				return scanner.Scan(driverValue.Interface())
			}
		}

	}
	return nil
}

func (t *SpecTest) haveError(fn interface{}) (bool, error) {
	t.doDebug(func() { t.Logf("Function %#v has an error", fn) })

	var errval reflect.Value
	switch fn.(type) {
	case FnCall:
		fncall := fn.(FnCall)
		fntyp := fncall.fn.Type()
		if !reflect.TypeOf(errors.New("error")).AssignableTo(fntyp.Out(fntyp.NumOut() - 1)) {
			return false, errors.New("HaveError function call's last Value must be os.Error")
		}
		errval = fncall.out[len(fncall.out)-1]
	default:
		return false, errors.New("HaveError needs a function call Value")
	}

	var fnerr error
	switch v := errval.Interface(); v.(type) {
	case nil:
		fnerr = nil
	case error:
		fnerr = v.(error)
	default:
		return false, errors.New("Function call can not have error")
	}
	return fnerr != nil, nil
}

func (d *decoder) parse_unmarshaler(v reflect.Value) bool {
	m, ok := v.Interface().(Unmarshaler)
	if !ok {
		// T doesn't work, try *T
		if v.Kind() != reflect.Ptr && v.CanAddr() {
			m, ok = v.Addr().Interface().(Unmarshaler)
			if ok {
				v = v.Addr()
			}
		}
	}
	if ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
		if d.read_one_value() {
			err := m.UnmarshalBencode(d.buf.Bytes())
			d.buf.Reset()
			if err != nil {
				panic(&UnmarshalerError{v.Type(), err})
			}
			return true
		}
		d.buf.Reset()
	}

	return false
}

// callSliceRequired returns true if CallSlice is required instead of Call.
func callSliceRequired(param reflect.Type, val reflect.Value) bool {
	vt := val.Type()
	for param.Kind() == reflect.Slice {
		if val.Kind() == reflect.Interface {
			val = reflect.ValueOf(val.Interface())
			vt = val.Type()
		}

		if vt.Kind() != reflect.Slice {
			return false
		}

		vt = vt.Elem()
		if val.Kind() != reflect.Invalid {
			if val.Len() > 0 {
				val = val.Index(0)
			} else {
				val = reflect.Value{}
			}
		}
		param = param.Elem()
	}

	return true
}

func (scope *Scope) getColumnsAsScope(column string) *Scope {
	values := scope.IndirectValue()
	switch values.Kind() {
	case reflect.Slice:
		modelType := values.Type().Elem()
		if modelType.Kind() == reflect.Ptr {
			modelType = modelType.Elem()
		}
		fieldStruct, _ := modelType.FieldByName(column)
		var columns reflect.Value
		if fieldStruct.Type.Kind() == reflect.Slice || fieldStruct.Type.Kind() == reflect.Ptr {
			columns = reflect.New(reflect.SliceOf(reflect.PtrTo(fieldStruct.Type.Elem()))).Elem()
		} else {
			columns = reflect.New(reflect.SliceOf(reflect.PtrTo(fieldStruct.Type))).Elem()
		}
		for i := 0; i < values.Len(); i++ {
			column := reflect.Indirect(values.Index(i)).FieldByName(column)
			if column.Kind() == reflect.Ptr {
				column = column.Elem()
			}
			if column.Kind() == reflect.Slice {
				for i := 0; i < column.Len(); i++ {
					columns = reflect.Append(columns, column.Index(i).Addr())
				}
			} else {
				columns = reflect.Append(columns, column.Addr())
			}
		}
		return scope.New(columns.Interface())
	case reflect.Struct:
		return scope.New(values.FieldByName(column).Addr().Interface())
	}
	return nil
}

func (f encFnInfo) getValueForMarshalInterface(rv reflect.Value, indir int8) (v interface{}, proceed bool) {
	if indir == 0 {
		v = rv.Interface()
	} else if indir == -1 {
		// If a non-pointer was passed to Encode(), then that value is not addressable.
		// Take addr if addresable, else copy value to an addressable value.
		if rv.CanAddr() {
			v = rv.Addr().Interface()
		} else {
			rv2 := reflect.New(rv.Type())
			rv2.Elem().Set(rv)
			v = rv2.Interface()
			// fmt.Printf("rv.Type: %v, rv2.Type: %v, v: %v\n", rv.Type(), rv2.Type(), v)
		}
	} else {
		for j := int8(0); j < indir; j++ {
			if rv.IsNil() {
				f.ee.EncodeNil()
				return
			}
			rv = rv.Elem()
		}
		v = rv.Interface()
	}
	return v, true
}

func (f encFnInfo) ext(rv reflect.Value) {
	// if this is a struct|array and it was addressable, then pass the address directly (not the value)
	if k := rv.Kind(); (k == reflect.Struct || k == reflect.Array) && rv.CanAddr() {
		rv = rv.Addr()
	}
	f.ee.EncodeExt(rv.Interface(), f.xfTag, f.xfFn, f.e)
}

func isZero(v reflect.Value) bool {
	switch v.Kind() {
	case reflect.Func, reflect.Map, reflect.Slice:
		return v.IsNil()
	case reflect.Array:
		z := true
		for i := 0; i < v.Len(); i++ {
			z = z && isZero(v.Index(i))
		}
		return z
	case reflect.Struct:
		if v.Type() == reflect.TypeOf(t) {
			if v.Interface().(time.Time).IsZero() {
				return true
			}
			return false
		}
		z := true
		for i := 0; i < v.NumField(); i++ {
			z = z && isZero(v.Field(i))
		}
		return z
	}
	// Compare other types directly:
	z := reflect.Zero(v.Type())
	return v.Interface() == z.Interface()
}