Improve resource record implementation in the mdns package.

pkg/mdns/test/decode_test.dart

Index: pkg/mdns/test/decode_test.dart
diff --git a/pkg/mdns/test/decode_test.dart b/pkg/mdns/test/decode_test.dart
index b17fddcfeb87b9a309f80ba47002137af052c4f0..1f7a913d074260c565b0fb4561c2757bf571bd0e 100644
--- a/pkg/mdns/test/decode_test.dart
+++ b/pkg/mdns/test/decode_test.dart
@@ -25,9 +25,29 @@ testValidPackages() {
   Expect.equals('raspberrypi.local', result[1].name);
   Expect.equals('169.254.95.83', result[1].address.address);
 
-  // This packet has no IPv4 address.
   result = decodeMDnsResponse(package3);
-  Expect.equals(0, result.length);
+  Expect.equals(8, result.length);
+  Expect.equals("""
+RR 16 [0]
+RR 12 raspberrypi._udisks-ssh._tcp.local
+RR 33 raspberrypi.local
+RR 16 [0]
+RR 12 _udisks-ssh._tcp.local
+RR 12 raspberrypi [b8:27:eb:03:92:4b]._workstation._tcp.local
+RR 33 raspberrypi.local
+RR 12 _workstation._tcp.local""",
+      result.join('\n'));
+
+  result = decodeMDnsResponse(packagePtrResponse);
+  Expect.equals(6, result.length);
+  Expect.equals("""
+RR 12 fletch-agent on raspberrypi._fletch_agent._tcp.local
+RR 16 [0]
+RR 33 raspberrypi.local
+RR 28 [254, 128, 0, 0, 0, 0, 0, 0, 186, 39, 235, 255, 254, 105, 110, 58]
+RR 1 InternetAddress('192.168.1.1', IP_V4)
+RR 1 InternetAddress('169.254.167.172', IP_V4)""",
+      result.join('\n'));
 }
 
 testBadPackages() {
@@ -40,6 +60,7 @@ testBadPackages() {
 
 testHexDumpList() {
   // Call hexDumpList to get rid of hint.
+  formatHexStream("");
   hexDumpList([]);
 }
 
@@ -63,7 +84,7 @@ var package2 = [
     0x01, 0x80, 0x01, 0x00, 0x00, 0x00, 0x78, 0x00,
     0x04, 0xa9, 0xfe, 0x5f, 0x53];
 
-// Seven mixed answers.
+// Eight mixed answers.
 var package3 = [
     0x00, 0x00, 0x84, 0x00, 0x00, 0x00, 0x00, 0x08,
     0x00, 0x00, 0x00, 0x00, 0x1f, 0x72, 0x61, 0x73,
@@ -97,6 +118,50 @@ var package3 = [
     0xc0, 0x88, 0xc0, 0xa3, 0x00, 0x0c, 0x00, 0x01,
     0x00, 0x00, 0x11, 0x94, 0x00, 0x02, 0xc0, 0x2c];
 
+var packagePtrResponse = <int>[
+  0x00, 0x00, 0x84, 0x00, 0x00, 0x00, 0x00, 0x06,
+  0x00, 0x00, 0x00, 0x00, 0x0d, 0x5f, 0x66, 0x6c,
+  0x65, 0x74, 0x63, 0x68, 0x5f, 0x61, 0x67, 0x65,
+  0x6e, 0x74, 0x04, 0x5f, 0x74, 0x63, 0x70, 0x05,
+  0x6c, 0x6f, 0x63, 0x61, 0x6c, 0x00, 0x00, 0x0c,
+  0x00, 0x01, 0x00, 0x00, 0x11, 0x94, 0x00, 0x1e,
+  0x1b, 0x66, 0x6c, 0x65, 0x74, 0x63, 0x68, 0x2d,
+  0x61, 0x67, 0x65, 0x6e, 0x74, 0x20, 0x6f, 0x6e,
+  0x20, 0x72, 0x61, 0x73, 0x70, 0x62, 0x65, 0x72,
+  0x72, 0x79, 0x70, 0x69, 0xc0, 0x0c, 0xc0, 0x30,
+  0x00, 0x10, 0x80, 0x01, 0x00, 0x00, 0x11, 0x94,
+  0x00, 0x01, 0x00, 0xc0, 0x30, 0x00, 0x21, 0x80,
+  0x01, 0x00, 0x00, 0x00, 0x78, 0x00, 0x14, 0x00,
+  0x00, 0x00, 0x00, 0x2f, 0x59, 0x0b, 0x72, 0x61,
+  0x73, 0x70, 0x62, 0x65, 0x72, 0x72, 0x79, 0x70,
+  0x69, 0xc0, 0x1f, 0xc0, 0x6d, 0x00, 0x1c, 0x80,
+  0x01, 0x00, 0x00, 0x00, 0x78, 0x00, 0x10, 0xfe,
+  0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xba,
+  0x27, 0xeb, 0xff, 0xfe, 0x69, 0x6e, 0x3a, 0xc0,
+  0x6d, 0x00, 0x01, 0x80, 0x01, 0x00, 0x00, 0x00,
+  0x78, 0x00, 0x04, 0xc0, 0xa8, 0x01, 0x01, 0xc0,
+  0x6d, 0x00, 0x01, 0x80, 0x01, 0x00, 0x00, 0x00,
+  0x78, 0x00, 0x04, 0xa9, 0xfe, 0xa7, 0xac
+];
+
+// Support code to generate the hex-lists above from
+// a hex-stream.
+void formatHexStream(String hexStream) {
+  var s = '';
+  for (int i = 0; i < hexStream.length / 2; i++) {
+    if (s.length != 0) s += ', ';
+    s += '0x';
+    var x = hexStream.substring(i * 2, i * 2 + 2);
+    s += x;
+    if (((i + 1) % 8) == 0) {
+      s += ',';
+      print(s);
+      s = '';
+    }
+  }
+  if (s.length != 0) print(s);
+}
+
 // Support code for generating the hex-lists above.
 void hexDumpList(List package) {
   var s = '';