func scanETag()

in internal/vfs/serving/serving.go [83:106]

• 21 lines of code
• 9 McCabe index (conditional complexity)

func scanETag(s string) (etag string, remain string) {
	s = textproto.TrimString(s)
	start := 0
	if strings.HasPrefix(s, "W/") {
		start = 2
	}
	if len(s[start:]) < 2 || s[start] != '"' {
		return "", ""
	}
	// ETag is either W/"text" or "text".
	// See RFC 7232 2.3.
	for i := start + 1; i < len(s); i++ {
		c := s[i]
		switch {
		// Character values allowed in ETags.
		case c == 0x21 || c >= 0x23 && c <= 0x7E || c >= 0x80:
		case c == '"':
			return s[:i+1], s[i+1:]
		default:
			return "", ""
		}
	}
	return "", ""
}