encoding/xml: handle anonymous pointer fields
This CL makes
type T struct { *U }
behave in a similar way to:
type T struct { U }
Fixes #3108.
R=golang-dev, rsc, gustavo
CC=golang-dev
https://golang.org/cl/5694044
diff --git a/src/pkg/encoding/xml/marshal.go b/src/pkg/encoding/xml/marshal.go
index 6c3170b..51e1dc8 100644
--- a/src/pkg/encoding/xml/marshal.go
+++ b/src/pkg/encoding/xml/marshal.go
@@ -57,8 +57,8 @@
// 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.
-// - a non-pointer anonymous struct field is handled as if the
-// fields of its value were part of the outer struct.
+// - an anonymous struct field is handled as if the fields of its
+// value were part of the outer struct.
//
// 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
@@ -164,7 +164,7 @@
xmlname := tinfo.xmlname
if xmlname.name != "" {
xmlns, name = xmlname.xmlns, xmlname.name
- } else if v, ok := val.FieldByIndex(xmlname.idx).Interface().(Name); ok && v.Local != "" {
+ } else if v, ok := xmlname.value(val).Interface().(Name); ok && v.Local != "" {
xmlns, name = v.Space, v.Local
}
}
@@ -195,7 +195,7 @@
if finfo.flags&fAttr == 0 {
continue
}
- fv := val.FieldByIndex(finfo.idx)
+ fv := finfo.value(val)
if finfo.flags&fOmitEmpty != 0 && isEmptyValue(fv) {
continue
}
@@ -276,7 +276,7 @@
if finfo.flags&(fAttr|fAny) != 0 {
continue
}
- vf := val.FieldByIndex(finfo.idx)
+ vf := finfo.value(val)
switch finfo.flags & fMode {
case fCharData:
switch vf.Kind() {
diff --git a/src/pkg/encoding/xml/marshal_test.go b/src/pkg/encoding/xml/marshal_test.go
index b6978a1..90b4925 100644
--- a/src/pkg/encoding/xml/marshal_test.go
+++ b/src/pkg/encoding/xml/marshal_test.go
@@ -108,7 +108,7 @@
type EmbedB struct {
FieldB string
- EmbedC
+ *EmbedC
}
type EmbedC struct {
@@ -493,7 +493,7 @@
},
EmbedB: EmbedB{
FieldB: "A.B.B",
- EmbedC: EmbedC{
+ EmbedC: &EmbedC{
FieldA1: "A.B.C.A1",
FieldA2: "A.B.C.A2",
FieldB: "", // Shadowed by A.B.B
diff --git a/src/pkg/encoding/xml/read.go b/src/pkg/encoding/xml/read.go
index c216824..0e6761d 100644
--- a/src/pkg/encoding/xml/read.go
+++ b/src/pkg/encoding/xml/read.go
@@ -81,8 +81,8 @@
// of the above rules and the struct has a field with tag ",any",
// unmarshal maps the sub-element to that struct field.
//
-// * A non-pointer anonymous struct field is handled as if the
-// fields of its value were part of the outer struct.
+// * An anonymous struct field is handled as if the fields of its
+// value were part of the outer struct.
//
// * A struct field with tag "-" is never unmarshalled into.
//
@@ -248,7 +248,7 @@
}
return UnmarshalError(e)
}
- fv := sv.FieldByIndex(finfo.idx)
+ fv := finfo.value(sv)
if _, ok := fv.Interface().(Name); ok {
fv.Set(reflect.ValueOf(start.Name))
}
@@ -260,7 +260,7 @@
finfo := &tinfo.fields[i]
switch finfo.flags & fMode {
case fAttr:
- strv := sv.FieldByIndex(finfo.idx)
+ strv := finfo.value(sv)
// Look for attribute.
for _, a := range start.Attr {
if a.Name.Local == finfo.name {
@@ -271,22 +271,22 @@
case fCharData:
if !saveData.IsValid() {
- saveData = sv.FieldByIndex(finfo.idx)
+ saveData = finfo.value(sv)
}
case fComment:
if !saveComment.IsValid() {
- saveComment = sv.FieldByIndex(finfo.idx)
+ saveComment = finfo.value(sv)
}
case fAny:
if !saveAny.IsValid() {
- saveAny = sv.FieldByIndex(finfo.idx)
+ saveAny = finfo.value(sv)
}
case fInnerXml:
if !saveXML.IsValid() {
- saveXML = sv.FieldByIndex(finfo.idx)
+ saveXML = finfo.value(sv)
if p.saved == nil {
saveXMLIndex = 0
p.saved = new(bytes.Buffer)
@@ -461,7 +461,7 @@
}
if len(finfo.parents) == len(parents) && finfo.name == start.Name.Local {
// It's a perfect match, unmarshal the field.
- return true, p.unmarshal(sv.FieldByIndex(finfo.idx), start)
+ return true, p.unmarshal(finfo.value(sv), start)
}
if len(finfo.parents) > len(parents) && finfo.parents[len(parents)] == start.Name.Local {
// It's a prefix for the field. Break and recurse
diff --git a/src/pkg/encoding/xml/typeinfo.go b/src/pkg/encoding/xml/typeinfo.go
index 8e2e450..970d170 100644
--- a/src/pkg/encoding/xml/typeinfo.go
+++ b/src/pkg/encoding/xml/typeinfo.go
@@ -66,10 +66,14 @@
// For embedded structs, embed its fields.
if f.Anonymous {
- if f.Type.Kind() != reflect.Struct {
+ t := f.Type
+ if t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ if t.Kind() != reflect.Struct {
continue
}
- inner, err := getTypeInfo(f.Type)
+ inner, err := getTypeInfo(t)
if err != nil {
return nil, err
}
@@ -327,3 +331,22 @@
func (e *TagPathError) Error() string {
return fmt.Sprintf("%s field %q with tag %q conflicts with field %q with tag %q", e.Struct, e.Field1, e.Tag1, e.Field2, e.Tag2)
}
+
+// value returns v's field value corresponding to finfo.
+// It's equivalent to v.FieldByIndex(finfo.idx), but initializes
+// and dereferences pointers as necessary.
+func (finfo *fieldInfo) value(v reflect.Value) reflect.Value {
+ for i, x := range finfo.idx {
+ if i > 0 {
+ t := v.Type()
+ if t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Struct {
+ if v.IsNil() {
+ v.Set(reflect.New(v.Type().Elem()))
+ }
+ v = v.Elem()
+ }
+ }
+ v = v.Field(x)
+ }
+ return v
+}
