Add support for cloning server-sockets.

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..f771a63ed4f7f5760f3164092e42601e42bee177 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -838,8 +838,8 @@ class _NativeSocket extends NativeFieldWrapperClass1 {
 
   void returnTokens() {
     if (eventPort != null && !isClosing && !isClosed) {
-      if (tokens == 8) {
-        // Return in batches of 8.
+      if (tokens == 2) {

[Søren Gjesse, 2014/04/25 12:24:44]

Please add a constant for this.

[Anders Johnsen, 2014/05/01 11:34:50]

Done.

+        // Return in batches of 2.
         assert(tokens < (1 << FIRST_COMMAND));
         sendToEventHandler((1 << RETURN_TOKEN_COMMAND) | tokens);
         tokens = 0;
@@ -1053,6 +1053,7 @@ class _NativeSocket extends NativeFieldWrapperClass1 {
   nativeAccept(_NativeSocket socket) native "ServerSocket_Accept";
   int nativeGetPort() native "Socket_GetPort";
   List nativeGetRemotePeer() native "Socket_GetRemotePeer";
+  int nativeGetSocketId() native "Socket_GetSocketId";
   OSError nativeGetError() native "Socket_GetError";
   nativeGetOption(int option, int protocol) native "Socket_GetOption";
   bool nativeSetOption(int option, int protocol, value)
@@ -1147,6 +1148,38 @@ class _RawServerSocket extends Stream<RawSocket>
       _resume();
     }
   }
+
+  RawServerSocketHandle clone() {
+    var port = new ReceivePort();
+    port.first.then((sendPort) {
+      sendPort.send(
+        [_socket.nativeGetSocketId(),
+         _socket.address,
+         _socket.localPort]);
+      port.close();
+    });
+    return new _RawServerSocketHandle(port.sendPort);
+  }
+}
+
+
+class _RawServerSocketHandle implements RawServerSocketHandle {
+  final SendPort _sendPort;
+
+  _RawServerSocketHandle(this._sendPort);
+
+  Future<RawServerSocket> acquire() {
+    var port = new ReceivePort();
+    _sendPort.send(port.sendPort);
+    return port.first.then((args) {
+      port.close();
+      var native = new _NativeSocket.listen();
+      native.nativeSetSocketId(args[0]);
+      native.address = args[1];
+      native.localPort = args[2];
+      return new _RawServerSocket(native);
+    });
+  }
 }
 
 
@@ -1307,6 +1340,18 @@ patch class ServerSocket {
   }
 }
 
+
+class _ServerSocketHandle implements ServerSocketHandle {
+  final RawServerSocketHandle _rawHandle;
+
+  _ServerSocketHandle(this._rawHandle);
+
+  Future<ServerSocket> acquire() {
+    return _rawHandle.acquire().then((raw) => new _ServerSocket(raw));
+  }
+}
+
+
 class _ServerSocket extends Stream<Socket>
                     implements ServerSocket {
   final _socket;
@@ -1337,6 +1382,10 @@ class _ServerSocket extends Stream<Socket>
   InternetAddress get address => _socket.address;
 
   Future close() => _socket.close().then((_) => this);
+
+  ServerSocketHandle clone() {
+    return new _ServerSocketHandle(_socket.clone());
+  }
 }