conditional_unit.go

package mpd

import (
	"encoding/xml"
	"fmt"
	"strconv"
)

// ConditionalUint (ConditionalUintType) defined in XSD as a union of unsignedInt and boolean.
type ConditionalUint struct {
	u *uint64
	b *bool
}

// MarshalXMLAttr encodes ConditionalUint.
func (c ConditionalUint) MarshalXMLAttr(name xml.Name) (xml.Attr, error) {
	if c.u != nil {
		return xml.Attr{Name: name, Value: strconv.FormatUint(*c.u, 10)}, nil
	}

	if c.b != nil {
		return xml.Attr{Name: name, Value: strconv.FormatBool(*c.b)}, nil
	}

	// both are nil - no attribute, client will threat it like "false"
	return xml.Attr{}, nil
}

// UnmarshalXMLAttr decodes ConditionalUint.
func (c *ConditionalUint) UnmarshalXMLAttr(attr xml.Attr) error {
	u, err := strconv.ParseUint(attr.Value, 10, 64)
	if err == nil {
		c.u = &u
		return nil
	}

	b, err := strconv.ParseBool(attr.Value)
	if err == nil {
		c.b = &b
		return nil
	}

	return fmt.Errorf("ConditionalUint: can't UnmarshalXMLAttr %#v", attr)
}

// check interfaces
var (
	_ xml.MarshalerAttr   = ConditionalUint{}
	_ xml.UnmarshalerAttr = &ConditionalUint{}
)