Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

encoding/xml: add support for the omitempty flag

Browse source 
This also changes the behavior of attribute marshalling so
that strings and byte slices are marshalled even if empty.
The omitempty flag may be used to obtain the previous behavior.

Fixes #2899.

R=rsc
CC=golang-dev
https://golang.org/cl/5645050
This commit is contained in:
Gustavo Niemeyer 2012-02-08 01:57:44 -02:00
parent 63975807c9
commit 0a7ad329e1
4 changed files with 124 additions and 19 deletions
Download patch file Download diff file Expand all files Collapse all files

36
src/pkg/encoding/xml/marshal.go
View file

@ -52,6 +52,10 @@ const (
// - a field with tag ",comment" is written as an XML comment, not
// subject to the usual marshalling procedure. It must not contain
// the "--" string within it.
// - a field with a tag including the "omitempty" option is omitted
// if the field value is empty. The empty values are false, 0, any
// nil pointer or interface value, and any array, slice, map, or
// string of length zero.
//
// If a field uses a tag "a>b>c", then the element c will be nested inside
// parent elements a and b. Fields that appear next to each other that name
@ -63,6 +67,8 @@ const (
// FirstName string `xml:"person>name>first"`
// LastName string `xml:"person>name>last"`
// Age int `xml:"person>age"`
// Height float `xml:"person>height,omitempty"`
// Married bool `xml:"person>married"`
// }
//
// xml.Marshal(&Result{Id: 13, FirstName: "John", LastName: "Doe", Age: 42})
@ -76,6 +82,7 @@ const (
// <last>Doe</last>
// </name>
// <age>42</age>
// <married>false</married>
// </person>
// </result>
//
@ -116,6 +123,9 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo) error {
if !val.IsValid() {
return nil
}
if finfo != nil && finfo.flags&fOmitEmpty != 0 && isEmptyValue(val) {
return nil
}
kind := val.Kind()
typ := val.Type()
@ -183,12 +193,8 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo) error {
continue
}
fv := val.FieldByIndex(finfo.idx)
switch fv.Kind() {
case reflect.String, reflect.Array, reflect.Slice:
// TODO: Should we really do this once ,omitempty is in?
if fv.Len() == 0 {
continue
}
if finfo.flags&fOmitEmpty != 0 && isEmptyValue(fv) {
continue
}
p.WriteByte(' ')
p.WriteString(finfo.name)
@ -378,3 +384,21 @@ type UnsupportedTypeError struct {
func (e *UnsupportedTypeError) Error() string {
return "xml: unsupported type: " + e.Type.String()
}
func isEmptyValue(v reflect.Value) bool {
switch v.Kind() {
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
return v.Len() == 0
case reflect.Bool:
return !v.Bool()
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.Interface, reflect.Ptr:
return v.IsNil()
}
return false
}