Make Socket::connect try all addresses given.

runtime/bin/socket_patch.dart

Index: runtime/bin/socket_patch.dart
diff --git a/runtime/bin/socket_patch.dart b/runtime/bin/socket_patch.dart
index 59faecf0918c3ea10c5095c9c5acee4f079f2490..3d096dfd8feba6981ef24026093aedfbd5f76a6d 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -481,40 +481,51 @@ class _NativeSocket extends NativeFieldWrapperClass1 {
   static Future<_NativeSocket> connect(host, int port) {
     return new Future.value(host)
         .then((host) {
-          if (host is _InternetAddress) return host;
+          if (host is _InternetAddress) return [host];
           return lookup(host)
               .then((list) {
                 if (list.length == 0) {
                   throw createError(response, "Failed host lookup: '$host'");
                 }
-                return list[0];
+                return list;
               });
         })
-        .then((address) {
-          var socket = new _NativeSocket.normal();
-          socket.address = address;
-          var result = socket.nativeCreateConnect(
-              address._in_addr, port);
-          if (result is OSError) {
-            throw createError(result, "Connection failed", address, port);
-          } else {
-            socket.port;  // Query the local port, for error messages.
-            var completer = new Completer();
-            // Setup handlers for receiving the first write event which
-            // indicate that the socket is fully connected.
-            socket.setHandlers(
-                write: () {
-                  socket.setListening(read: false, write: false);
-                  completer.complete(socket);
-                },
-                error: (e) {
-                  socket.close();
-                  completer.completeError(e);
-                }
-            );
-            socket.setListening(read: false, write: true);
-            return completer.future;
+        .then((addresses) {
+          assert(addresses is List);
+          var completer = new Completer();
+          var it = addresses.iterator;
+          void run(error) {
+            if (!it.moveNext()) {
+              assert(error != null);
+              completer.completeError(error);
+              return;
+            }
+            var address = it.current;
+            var socket = new _NativeSocket.normal();
+            socket.address = address;
+            var result = socket.nativeCreateConnect(address._in_addr, port);
+            if (result is OSError) {
+              run(error != null ? error :
+                  createError(result, "Connection failed", address, port));
+            } else {
+              socket.port;  // Query the local port, for error messages.
+              // Setup handlers for receiving the first write event which
+              // indicate that the socket is fully connected.
+              socket.setHandlers(
+                  write: () {
+                    socket.setListening(read: false, write: false);
+                    completer.complete(socket);
+                  },
+                  error: (e) {
+                    socket.close();

[Søren Gjesse, 2014/05/01 07:23:34]

Add a comment that this keeps the first error.

[Anders Johnsen, 2014/05/01 08:42:38]

Done.

+                    run(error != null ? error : e);

[codefu, 2014/05/01 18:52:02]

If addresses.length > 1 and the first address connects... if later in time the
socket has an error won't this try to reconnect on later addresses (and possibly
throw an error since completer is already done)?

suggested: bool retry = true; before run(), then retry = false just before
comleter.complete(socket).  in error if(retry) run(...);

[Anders Johnsen, 2014/05/01 19:27:58]

No, this error handler is only called when connecting fails. As soon as the
connection is made, we disable listening (see above) and later register another
error handler.

+                  }
+              );
+              socket.setListening(read: false, write: true);
+            }
           }
+          run(null);
+          return completer.future;
         });
   }