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dex/vendor/github.com/russellhaering/goxmldsig/canonicalize.go

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package dsig
import (
"sort"
"github.com/beevik/etree"
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"github.com/russellhaering/goxmldsig/etreeutils"
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)
// Canonicalizer is an implementation of a canonicalization algorithm.
type Canonicalizer interface {
Canonicalize(el *etree.Element) ([]byte, error)
Algorithm() AlgorithmID
}
type c14N10ExclusiveCanonicalizer struct {
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prefixList string
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}
// MakeC14N10ExclusiveCanonicalizerWithPrefixList constructs an exclusive Canonicalizer
// from a PrefixList in NMTOKENS format (a white space separated list).
func MakeC14N10ExclusiveCanonicalizerWithPrefixList(prefixList string) Canonicalizer {
return &c14N10ExclusiveCanonicalizer{
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prefixList: prefixList,
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}
}
// Canonicalize transforms the input Element into a serialized XML document in canonical form.
func (c *c14N10ExclusiveCanonicalizer) Canonicalize(el *etree.Element) ([]byte, error) {
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err := etreeutils.TransformExcC14n(el, c.prefixList)
if err != nil {
return nil, err
}
return canonicalSerialize(el)
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}
func (c *c14N10ExclusiveCanonicalizer) Algorithm() AlgorithmID {
return CanonicalXML10ExclusiveAlgorithmId
}
type c14N11Canonicalizer struct{}
// MakeC14N11Canonicalizer constructs an inclusive canonicalizer.
func MakeC14N11Canonicalizer() Canonicalizer {
return &c14N11Canonicalizer{}
}
// Canonicalize transforms the input Element into a serialized XML document in canonical form.
func (c *c14N11Canonicalizer) Canonicalize(el *etree.Element) ([]byte, error) {
scope := make(map[string]struct{})
return canonicalSerialize(canonicalPrep(el, scope))
}
func (c *c14N11Canonicalizer) Algorithm() AlgorithmID {
return CanonicalXML11AlgorithmId
}
func composeAttr(space, key string) string {
if space != "" {
return space + ":" + key
}
return key
}
type c14nSpace struct {
a etree.Attr
used bool
}
const nsSpace = "xmlns"
// canonicalPrep accepts an *etree.Element and transforms it into one which is ready
// for serialization into inclusive canonical form. Specifically this
// entails:
//
// 1. Stripping re-declarations of namespaces
// 2. Sorting attributes into canonical order
//
// Inclusive canonicalization does not strip unused namespaces.
//
// TODO(russell_h): This is very similar to excCanonicalPrep - perhaps they should
// be unified into one parameterized function?
func canonicalPrep(el *etree.Element, seenSoFar map[string]struct{}) *etree.Element {
_seenSoFar := make(map[string]struct{})
for k, v := range seenSoFar {
_seenSoFar[k] = v
}
ne := el.Copy()
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sort.Sort(etreeutils.SortedAttrs(ne.Attr))
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if len(ne.Attr) != 0 {
for _, attr := range ne.Attr {
if attr.Space != nsSpace {
continue
}
key := attr.Space + ":" + attr.Key
if _, seen := _seenSoFar[key]; seen {
ne.RemoveAttr(attr.Space + ":" + attr.Key)
} else {
_seenSoFar[key] = struct{}{}
}
}
}
for i, token := range ne.Child {
childElement, ok := token.(*etree.Element)
if ok {
ne.Child[i] = canonicalPrep(childElement, _seenSoFar)
}
}
return ne
}
func canonicalSerialize(el *etree.Element) ([]byte, error) {
doc := etree.NewDocument()
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doc.SetRoot(el.Copy())
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doc.WriteSettings = etree.WriteSettings{
CanonicalAttrVal: true,
CanonicalEndTags: true,
CanonicalText: true,
}
return doc.WriteToBytes()
}