Add support for IPv6 in System.Uri.DnsSafeHost

* System/Uri.cs: Fix DnsSafeHost for IPv6 addresses, removing the []
brackets and adding, when available, the scope id

* Test/System/UriTest2.cs: Add DnsSafeHost test cases for IPv6 address,
one without scope id, another with a scope id

mcs/class/System/System/Uri.cs

@@ -81,6 +81,7 @@ public class Uri : ISerializable {
 		private bool isUnc;
 		private bool isOpaquePart;
 		private bool isAbsoluteUri = true;
+		private long scope_id;
 
 		private List<string> segments;
 
@@ -676,11 +677,16 @@ private bool IsLocalIdenticalToAbsolutePath ()
 			}
 		}
 
-		[MonoTODO ("add support for IPv6 address")]
 		public string DnsSafeHost {
 			get {
 				EnsureAbsoluteUri ();
-				return Unescape (Host);
+				string host = Host;
+				if (HostNameType == UriHostNameType.IPv6) {
+					host = Host.Substring (1, Host.Length - 2);
+					if (scope_id != 0)
+						host += "%" + scope_id.ToString ();
+				}
+				return Unescape (host);
 			}
 		}
 
@@ -1568,9 +1574,10 @@ private string ParseNoExceptions (UriKind kind, string uriString)
 			if (!badhost && (host.Length > 1) && (host[0] == '[') && (host[host.Length - 1] == ']')) {
 				IPv6Address ipv6addr;
 
-				if (IPv6Address.TryParse (host, out ipv6addr))
+				if (IPv6Address.TryParse (host, out ipv6addr)) {
 					host = "[" + ipv6addr.ToString (true) + "]";
-				else
+					scope_id = ipv6addr.ScopeId;
+				} else
 					badhost = true;
 			}
 			if (badhost && (Parser is DefaultUriParser || Parser == null))

mcs/class/System/Test/System/UriTest2.cs

@@ -895,5 +895,21 @@ public void ColonButNoPort ()
 			Assert.AreEqual (21, uri.Port, "2.Port");
 			Assert.IsTrue (uri.IsDefaultPort, "2.IsDefaultPort");
 		}
+
+		[Test]
+		public void IPv6SafeDnsName ()
+		{
+			Uri uri = new Uri ("http://[1:2:3:4:5:6:7:8]");
+			Assert.AreEqual (UriHostNameType.IPv6, uri.HostNameType, "1.HostNameType");
+			Assert.AreEqual ("[0001:0002:0003:0004:0005:0006:0007:0008]", uri.Authority, "1.Authority");
+			Assert.AreEqual ("0001:0002:0003:0004:0005:0006:0007:0008", uri.DnsSafeHost, "1.DnsSafeHost");
+			Assert.AreEqual ("[0001:0002:0003:0004:0005:0006:0007:0008]", uri.Host, "1.Host");
+
+			uri = new Uri ("http://[fe80::200:39ff:fe36:1a2d%4]/temp/example.htm");
+			Assert.AreEqual (UriHostNameType.IPv6, uri.HostNameType, "1.HostNameType");
+			Assert.AreEqual ("[FE80:0000:0000:0000:0200:39FF:FE36:1A2D]", uri.Authority, "2.Authority");
+			Assert.AreEqual ("FE80:0000:0000:0000:0200:39FF:FE36:1A2D%4", uri.DnsSafeHost, "2.DnsSafeHost");
+			Assert.AreEqual ("[FE80:0000:0000:0000:0200:39FF:FE36:1A2D]", uri.Host, "2.Host");
+		}
 	}
 }