Method createAttrPrefix

opensca/sca/java/xml/marshal.go:337–394

createAttrPrefix finds the name space prefix attribute to use for the given name space, defining a new prefix if necessary. It returns the prefix.

(url string)

// createAttrPrefix finds the name space prefix attribute to use for the given name space,
// defining a new prefix if necessary. It returns the prefix.
func (p *printer) createAttrPrefix(url string) string {
	if prefix := p.attrPrefix[url]; prefix != "" {
		return prefix
	}

	// The "http://www.w3.org/XML/1998/namespace" name space is predefined as "xml"
	// and must be referred to that way.
	// (The "http://www.w3.org/2000/xmlns/" name space is also predefined as "xmlns",
	// but users should not be trying to use that one directly - that's our job.)
	if url == xmlURL {
		return xmlPrefix
	}

	// Need to define a new name space.
	if p.attrPrefix == nil {
		p.attrPrefix = make(map[string]string)
		p.attrNS = make(map[string]string)
	}

	// Pick a name. We try to use the final element of the path
	// but fall back to _.
	prefix := strings.TrimRight(url, "/")
	if i := strings.LastIndex(prefix, "/"); i >= 0 {
		prefix = prefix[i+1:]
	}
	if prefix == "" || !isName([]byte(prefix)) || strings.Contains(prefix, ":") {
		prefix = "_"
	}
	// xmlanything is reserved and any variant of it regardless of
	// case should be matched, so:
	//    (('X'|'x') ('M'|'m') ('L'|'l'))
	// See Section 2.3 of https://www.w3.org/TR/REC-xml/
	if len(prefix) >= 3 && strings.EqualFold(prefix[:3], "xml") {
		prefix = "_" + prefix
	}
	if p.attrNS[prefix] != "" {
		// Name is taken. Find a better one.
		for p.seq++; ; p.seq++ {
			if id := prefix + "_" + strconv.Itoa(p.seq); p.attrNS[id] == "" {
				prefix = id
				break
			}
		}
	}

	p.attrPrefix[url] = prefix
	p.attrNS[prefix] = url

	p.WriteString(`xmlns:`)
	p.WriteString(prefix)
	p.WriteString(`="`)
	EscapeText(p, []byte(url))
	p.WriteString(`" `)

	p.prefixes = append(p.prefixes, prefix)

	return prefix
}