mox!

dns/ipdomain.go

@@ -0,0 +1,42 @@
+package dns
+
+import (
+	"net"
+)
+
+// IPDomain is an ip address, a domain, or empty.
+type IPDomain struct {
+	IP     net.IP
+	Domain Domain
+}
+
+// IsZero returns if both IP and Domain are zero.
+func (d IPDomain) IsZero() bool {
+	return d.IP == nil && d.Domain == Domain{}
+}
+
+// String returns a string representation of either the IP or domain (with
+// UTF-8).
+func (d IPDomain) String() string {
+	if len(d.IP) > 0 {
+		return d.IP.String()
+	}
+	return d.Domain.Name()
+}
+
+// XString is like String, but only returns UTF-8 domains if utf8 is true.
+func (d IPDomain) XString(utf8 bool) string {
+	if d.IsIP() {
+		// todo: check callers if this is valid syntax for them. should we add [] for ipv6? perhaps also ipv4? probably depends on context. in smtp, the syntax is [<ipv4>] and [IPv6:<ipv6>].
+		return d.IP.String()
+	}
+	return d.Domain.XName(utf8)
+}
+
+func (d IPDomain) IsIP() bool {
+	return len(d.IP) > 0
+}
+
+func (d IPDomain) IsDomain() bool {
+	return !d.Domain.IsZero()
+}