532 lines
15 KiB
Go
532 lines
15 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package xml
|
|
|
|
import (
|
|
"bytes"
|
|
"errors"
|
|
"reflect"
|
|
"strconv"
|
|
"strings"
|
|
"time"
|
|
)
|
|
|
|
// BUG(rsc): Mapping between XML elements and data structures is inherently flawed:
|
|
// an XML element is an order-dependent collection of anonymous
|
|
// values, while a data structure is an order-independent collection
|
|
// of named values.
|
|
// See package json for a textual representation more suitable
|
|
// to data structures.
|
|
|
|
// Unmarshal parses the XML-encoded data and stores the result in
|
|
// the value pointed to by v, which must be an arbitrary struct,
|
|
// slice, or string. Well-formed data that does not fit into v is
|
|
// discarded.
|
|
//
|
|
// Because Unmarshal uses the reflect package, it can only assign
|
|
// to exported (upper case) fields. Unmarshal uses a case-sensitive
|
|
// comparison to match XML element names to tag values and struct
|
|
// field names.
|
|
//
|
|
// Unmarshal maps an XML element to a struct using the following rules.
|
|
// In the rules, the tag of a field refers to the value associated with the
|
|
// key 'xml' in the struct field's tag (see the example above).
|
|
//
|
|
// * If the struct has a field of type []byte or string with tag
|
|
// ",innerxml", Unmarshal accumulates the raw XML nested inside the
|
|
// element in that field. The rest of the rules still apply.
|
|
//
|
|
// * If the struct has a field named XMLName of type xml.Name,
|
|
// Unmarshal records the element name in that field.
|
|
//
|
|
// * If the XMLName field has an associated tag of the form
|
|
// "name" or "namespace-URL name", the XML element must have
|
|
// the given name (and, optionally, name space) or else Unmarshal
|
|
// returns an error.
|
|
//
|
|
// * If the XML element has an attribute whose name matches a
|
|
// struct field name with an associated tag containing ",attr" or
|
|
// the explicit name in a struct field tag of the form "name,attr",
|
|
// Unmarshal records the attribute value in that field.
|
|
//
|
|
// * If the XML element contains character data, that data is
|
|
// accumulated in the first struct field that has tag "chardata".
|
|
// The struct field may have type []byte or string.
|
|
// If there is no such field, the character data is discarded.
|
|
//
|
|
// * If the XML element contains comments, they are accumulated in
|
|
// the first struct field that has tag ",comments". The struct
|
|
// field may have type []byte or string. If there is no such
|
|
// field, the comments are discarded.
|
|
//
|
|
// * If the XML element contains a sub-element whose name matches
|
|
// the prefix of a tag formatted as "a" or "a>b>c", unmarshal
|
|
// will descend into the XML structure looking for elements with the
|
|
// given names, and will map the innermost elements to that struct
|
|
// field. A tag starting with ">" is equivalent to one starting
|
|
// with the field name followed by ">".
|
|
//
|
|
// * If the XML element contains a sub-element whose name matches
|
|
// a struct field's XMLName tag and the struct field has no
|
|
// explicit name tag as per the previous rule, unmarshal maps
|
|
// the sub-element to that struct field.
|
|
//
|
|
// * If the XML element contains a sub-element whose name matches a
|
|
// field without any mode flags (",attr", ",chardata", etc), Unmarshal
|
|
// maps the sub-element to that struct field.
|
|
//
|
|
// * If the XML element contains a sub-element that hasn't matched any
|
|
// 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.
|
|
//
|
|
// * A struct field with tag "-" is never unmarshalled into.
|
|
//
|
|
// Unmarshal maps an XML element to a string or []byte by saving the
|
|
// concatenation of that element's character data in the string or
|
|
// []byte. The saved []byte is never nil.
|
|
//
|
|
// Unmarshal maps an attribute value to a string or []byte by saving
|
|
// the value in the string or slice.
|
|
//
|
|
// Unmarshal maps an XML element to a slice by extending the length of
|
|
// the slice and mapping the element to the newly created value.
|
|
//
|
|
// Unmarshal maps an XML element or attribute value to a bool by
|
|
// setting it to the boolean value represented by the string.
|
|
//
|
|
// Unmarshal maps an XML element or attribute value to an integer or
|
|
// floating-point field by setting the field to the result of
|
|
// interpreting the string value in decimal. There is no check for
|
|
// overflow.
|
|
//
|
|
// Unmarshal maps an XML element to an xml.Name by recording the
|
|
// element name.
|
|
//
|
|
// Unmarshal maps an XML element to a pointer by setting the pointer
|
|
// to a freshly allocated value and then mapping the element to that value.
|
|
//
|
|
func Unmarshal(data []byte, v interface{}) error {
|
|
return NewDecoder(bytes.NewBuffer(data)).Decode(v)
|
|
}
|
|
|
|
// Decode works like xml.Unmarshal, except it reads the decoder
|
|
// stream to find the start element.
|
|
func (d *Decoder) Decode(v interface{}) error {
|
|
return d.DecodeElement(v, nil)
|
|
}
|
|
|
|
// DecodeElement works like xml.Unmarshal except that it takes
|
|
// a pointer to the start XML element to decode into v.
|
|
// It is useful when a client reads some raw XML tokens itself
|
|
// but also wants to defer to Unmarshal for some elements.
|
|
func (d *Decoder) DecodeElement(v interface{}, start *StartElement) error {
|
|
val := reflect.ValueOf(v)
|
|
if val.Kind() != reflect.Ptr {
|
|
return errors.New("non-pointer passed to Unmarshal")
|
|
}
|
|
return d.unmarshal(val.Elem(), start)
|
|
}
|
|
|
|
// An UnmarshalError represents an error in the unmarshalling process.
|
|
type UnmarshalError string
|
|
|
|
func (e UnmarshalError) Error() string { return string(e) }
|
|
|
|
// Unmarshal a single XML element into val.
|
|
func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
|
|
// Find start element if we need it.
|
|
if start == nil {
|
|
for {
|
|
tok, err := p.Token()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if t, ok := tok.(StartElement); ok {
|
|
start = &t
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
if pv := val; pv.Kind() == reflect.Ptr {
|
|
if pv.IsNil() {
|
|
pv.Set(reflect.New(pv.Type().Elem()))
|
|
}
|
|
val = pv.Elem()
|
|
}
|
|
|
|
var (
|
|
data []byte
|
|
saveData reflect.Value
|
|
comment []byte
|
|
saveComment reflect.Value
|
|
saveXML reflect.Value
|
|
saveXMLIndex int
|
|
saveXMLData []byte
|
|
saveAny reflect.Value
|
|
sv reflect.Value
|
|
tinfo *typeInfo
|
|
err error
|
|
)
|
|
|
|
switch v := val; v.Kind() {
|
|
default:
|
|
return errors.New("unknown type " + v.Type().String())
|
|
|
|
case reflect.Interface:
|
|
// TODO: For now, simply ignore the field. In the near
|
|
// future we may choose to unmarshal the start
|
|
// element on it, if not nil.
|
|
return p.Skip()
|
|
|
|
case reflect.Slice:
|
|
typ := v.Type()
|
|
if typ.Elem().Kind() == reflect.Uint8 {
|
|
// []byte
|
|
saveData = v
|
|
break
|
|
}
|
|
|
|
// Slice of element values.
|
|
// Grow slice.
|
|
n := v.Len()
|
|
if n >= v.Cap() {
|
|
ncap := 2 * n
|
|
if ncap < 4 {
|
|
ncap = 4
|
|
}
|
|
new := reflect.MakeSlice(typ, n, ncap)
|
|
reflect.Copy(new, v)
|
|
v.Set(new)
|
|
}
|
|
v.SetLen(n + 1)
|
|
|
|
// Recur to read element into slice.
|
|
if err := p.unmarshal(v.Index(n), start); err != nil {
|
|
v.SetLen(n)
|
|
return err
|
|
}
|
|
return nil
|
|
|
|
case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr, reflect.String:
|
|
saveData = v
|
|
|
|
case reflect.Struct:
|
|
typ := v.Type()
|
|
if typ == nameType {
|
|
v.Set(reflect.ValueOf(start.Name))
|
|
break
|
|
}
|
|
if typ == timeType {
|
|
saveData = v
|
|
break
|
|
}
|
|
|
|
sv = v
|
|
tinfo, err = getTypeInfo(typ)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Validate and assign element name.
|
|
if tinfo.xmlname != nil {
|
|
finfo := tinfo.xmlname
|
|
if finfo.name != "" && finfo.name != start.Name.Local {
|
|
return UnmarshalError("expected element type <" + finfo.name + "> but have <" + start.Name.Local + ">")
|
|
}
|
|
if finfo.xmlns != "" && finfo.xmlns != start.Name.Space {
|
|
e := "expected element <" + finfo.name + "> in name space " + finfo.xmlns + " but have "
|
|
if start.Name.Space == "" {
|
|
e += "no name space"
|
|
} else {
|
|
e += start.Name.Space
|
|
}
|
|
return UnmarshalError(e)
|
|
}
|
|
fv := sv.FieldByIndex(finfo.idx)
|
|
if _, ok := fv.Interface().(Name); ok {
|
|
fv.Set(reflect.ValueOf(start.Name))
|
|
}
|
|
}
|
|
|
|
// Assign attributes.
|
|
// Also, determine whether we need to save character data or comments.
|
|
for i := range tinfo.fields {
|
|
finfo := &tinfo.fields[i]
|
|
switch finfo.flags & fMode {
|
|
case fAttr:
|
|
strv := sv.FieldByIndex(finfo.idx)
|
|
// Look for attribute.
|
|
for _, a := range start.Attr {
|
|
if a.Name.Local == finfo.name {
|
|
copyValue(strv, []byte(a.Value))
|
|
break
|
|
}
|
|
}
|
|
|
|
case fCharData:
|
|
if !saveData.IsValid() {
|
|
saveData = sv.FieldByIndex(finfo.idx)
|
|
}
|
|
|
|
case fComment:
|
|
if !saveComment.IsValid() {
|
|
saveComment = sv.FieldByIndex(finfo.idx)
|
|
}
|
|
|
|
case fAny:
|
|
if !saveAny.IsValid() {
|
|
saveAny = sv.FieldByIndex(finfo.idx)
|
|
}
|
|
|
|
case fInnerXml:
|
|
if !saveXML.IsValid() {
|
|
saveXML = sv.FieldByIndex(finfo.idx)
|
|
if p.saved == nil {
|
|
saveXMLIndex = 0
|
|
p.saved = new(bytes.Buffer)
|
|
} else {
|
|
saveXMLIndex = p.savedOffset()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Find end element.
|
|
// Process sub-elements along the way.
|
|
Loop:
|
|
for {
|
|
var savedOffset int
|
|
if saveXML.IsValid() {
|
|
savedOffset = p.savedOffset()
|
|
}
|
|
tok, err := p.Token()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
switch t := tok.(type) {
|
|
case StartElement:
|
|
consumed := false
|
|
if sv.IsValid() {
|
|
consumed, err = p.unmarshalPath(tinfo, sv, nil, &t)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if !consumed && saveAny.IsValid() {
|
|
consumed = true
|
|
if err := p.unmarshal(saveAny, &t); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
}
|
|
if !consumed {
|
|
if err := p.Skip(); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
case EndElement:
|
|
if saveXML.IsValid() {
|
|
saveXMLData = p.saved.Bytes()[saveXMLIndex:savedOffset]
|
|
if saveXMLIndex == 0 {
|
|
p.saved = nil
|
|
}
|
|
}
|
|
break Loop
|
|
|
|
case CharData:
|
|
if saveData.IsValid() {
|
|
data = append(data, t...)
|
|
}
|
|
|
|
case Comment:
|
|
if saveComment.IsValid() {
|
|
comment = append(comment, t...)
|
|
}
|
|
}
|
|
}
|
|
|
|
if err := copyValue(saveData, data); err != nil {
|
|
return err
|
|
}
|
|
|
|
switch t := saveComment; t.Kind() {
|
|
case reflect.String:
|
|
t.SetString(string(comment))
|
|
case reflect.Slice:
|
|
t.Set(reflect.ValueOf(comment))
|
|
}
|
|
|
|
switch t := saveXML; t.Kind() {
|
|
case reflect.String:
|
|
t.SetString(string(saveXMLData))
|
|
case reflect.Slice:
|
|
t.Set(reflect.ValueOf(saveXMLData))
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func copyValue(dst reflect.Value, src []byte) (err error) {
|
|
// Helper functions for integer and unsigned integer conversions
|
|
var itmp int64
|
|
getInt64 := func() bool {
|
|
itmp, err = strconv.ParseInt(string(src), 10, 64)
|
|
// TODO: should check sizes
|
|
return err == nil
|
|
}
|
|
var utmp uint64
|
|
getUint64 := func() bool {
|
|
utmp, err = strconv.ParseUint(string(src), 10, 64)
|
|
// TODO: check for overflow?
|
|
return err == nil
|
|
}
|
|
var ftmp float64
|
|
getFloat64 := func() bool {
|
|
ftmp, err = strconv.ParseFloat(string(src), 64)
|
|
// TODO: check for overflow?
|
|
return err == nil
|
|
}
|
|
|
|
// Save accumulated data.
|
|
switch t := dst; t.Kind() {
|
|
case reflect.Invalid:
|
|
// Probably a comment.
|
|
default:
|
|
return errors.New("cannot happen: unknown type " + t.Type().String())
|
|
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
|
|
if !getInt64() {
|
|
return err
|
|
}
|
|
t.SetInt(itmp)
|
|
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
|
|
if !getUint64() {
|
|
return err
|
|
}
|
|
t.SetUint(utmp)
|
|
case reflect.Float32, reflect.Float64:
|
|
if !getFloat64() {
|
|
return err
|
|
}
|
|
t.SetFloat(ftmp)
|
|
case reflect.Bool:
|
|
value, err := strconv.ParseBool(strings.TrimSpace(string(src)))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
t.SetBool(value)
|
|
case reflect.String:
|
|
t.SetString(string(src))
|
|
case reflect.Slice:
|
|
if len(src) == 0 {
|
|
// non-nil to flag presence
|
|
src = []byte{}
|
|
}
|
|
t.SetBytes(src)
|
|
case reflect.Struct:
|
|
if t.Type() == timeType {
|
|
tv, err := time.Parse(time.RFC3339, string(src))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
t.Set(reflect.ValueOf(tv))
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// unmarshalPath walks down an XML structure looking for wanted
|
|
// paths, and calls unmarshal on them.
|
|
// The consumed result tells whether XML elements have been consumed
|
|
// from the Decoder until start's matching end element, or if it's
|
|
// still untouched because start is uninteresting for sv's fields.
|
|
func (p *Decoder) unmarshalPath(tinfo *typeInfo, sv reflect.Value, parents []string, start *StartElement) (consumed bool, err error) {
|
|
recurse := false
|
|
Loop:
|
|
for i := range tinfo.fields {
|
|
finfo := &tinfo.fields[i]
|
|
if finfo.flags&fElement == 0 || len(finfo.parents) < len(parents) {
|
|
continue
|
|
}
|
|
for j := range parents {
|
|
if parents[j] != finfo.parents[j] {
|
|
continue Loop
|
|
}
|
|
}
|
|
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)
|
|
}
|
|
if len(finfo.parents) > len(parents) && finfo.parents[len(parents)] == start.Name.Local {
|
|
// It's a prefix for the field. Break and recurse
|
|
// since it's not ok for one field path to be itself
|
|
// the prefix for another field path.
|
|
recurse = true
|
|
|
|
// We can reuse the same slice as long as we
|
|
// don't try to append to it.
|
|
parents = finfo.parents[:len(parents)+1]
|
|
break
|
|
}
|
|
}
|
|
if !recurse {
|
|
// We have no business with this element.
|
|
return false, nil
|
|
}
|
|
// The element is not a perfect match for any field, but one
|
|
// or more fields have the path to this element as a parent
|
|
// prefix. Recurse and attempt to match these.
|
|
for {
|
|
var tok Token
|
|
tok, err = p.Token()
|
|
if err != nil {
|
|
return true, err
|
|
}
|
|
switch t := tok.(type) {
|
|
case StartElement:
|
|
consumed2, err := p.unmarshalPath(tinfo, sv, parents, &t)
|
|
if err != nil {
|
|
return true, err
|
|
}
|
|
if !consumed2 {
|
|
if err := p.Skip(); err != nil {
|
|
return true, err
|
|
}
|
|
}
|
|
case EndElement:
|
|
return true, nil
|
|
}
|
|
}
|
|
panic("unreachable")
|
|
}
|
|
|
|
// Skip reads tokens until it has consumed the end element
|
|
// matching the most recent start element already consumed.
|
|
// It recurs if it encounters a start element, so it can be used to
|
|
// skip nested structures.
|
|
// It returns nil if it finds an end element matching the start
|
|
// element; otherwise it returns an error describing the problem.
|
|
func (d *Decoder) Skip() error {
|
|
for {
|
|
tok, err := d.Token()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
switch tok.(type) {
|
|
case StartElement:
|
|
if err := d.Skip(); err != nil {
|
|
return err
|
|
}
|
|
case EndElement:
|
|
return nil
|
|
}
|
|
}
|
|
panic("unreachable")
|
|
}
|