func processTransform(transform *etree.Element,
docIn *etree.Document) (docOut *etree.Document, err error) {
transformAlgoURI := transform.SelectAttrValue("Algorithm", "")
if transformAlgoURI == "" {
return nil, errors.New("signedxml: unable to find Algorithm in Transform")
}
transformAlgo, ok := CanonicalizationAlgorithms[transformAlgoURI]
if !ok {
return nil, fmt.Errorf("signedxml: unable to find matching transform"+
"algorithm for %s in CanonicalizationAlgorithms", transformAlgoURI)
}
var transformContent string
if transform.ChildElements() != nil {
tDoc := etree.NewDocument()
tDoc.SetRoot(transform.Copy())
transformContent, err = tDoc.WriteToString()
if err != nil {
return nil, err
}
}
docString, err := docIn.WriteToString()
if err != nil {
return nil, err
}
docString, err = transformAlgo.Process(docString, transformContent)
if err != nil {
return nil, err
}
docOut = etree.NewDocument()
docOut.ReadFromString(docString)
return docOut, nil
}
