Revert "Extend the mDNS package with a native extension used on Mac OS"

src/pkg/mdns/mdns_extension.cc

-// Copyright (c) 2015, the Fletch project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE.md file.
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "include/dart_api.h"
-#include "include/dart_native_api.h"
-
-#include "mdns_extension.h"
-
-// Handle request send on the service port.
-void HandleRequest(Dart_Port port_id, Dart_CObject* message) {
-  // Messages are expected to be three item lists:
-  //  [0]: reply port
-  //  [1]: request type
-  //  [2]: request argument
-  if (message->type == Dart_CObject_kArray &&
-      message->value.as_array.length == 3) {
-    Dart_CObject* reply_port = message->value.as_array.values[0];
-    Dart_CObject* request_type = message->value.as_array.values[1];
-    Dart_CObject* argument = message->value.as_array.values[2];
-    if (reply_port->type == Dart_CObject_kSendPort) {
-      if (request_type->type == Dart_CObject_kInt32) {
-        switch (request_type->value.as_int32) {
-          case kEchoRequest:
-            HandleEcho(reply_port->value.as_send_port.id, argument);
-            return;
-
-          case kLookupRequest:
-            HandleLookup(reply_port->value.as_send_port.id,
-                         argument->value.as_string);
-            return;
-
-          default:
-            break;
-            // Ignore invalid requests.
-        }
-      }
-      Dart_CObject result;
-      result.type = Dart_CObject_kNull;
-      Dart_PostCObject(reply_port->value.as_send_port.id, &result);
-    }
-  }
-}
-
-// Handler for the echo request. Used for testing that the native extension
-// can be loaded and called.
-void HandleEcho(Dart_Port reply_port, Dart_CObject* argument) {
-  Dart_PostCObject(reply_port, argument);
-}
-
-
-Dart_Handle HandleError(Dart_Handle handle) {
-  if (Dart_IsError(handle)) Dart_PropagateError(handle);
-  return handle;
-}
-
-
-// Initialize a native port with a request handler.
-void ServicePort(Dart_NativeArguments arguments) {
-  Dart_SetReturnValue(arguments, Dart_Null());
-  Dart_Port service_port =
-      Dart_NewNativePort("MDnsService", HandleRequest, true);
-  if (service_port != ILLEGAL_PORT) {
-    Dart_Handle send_port = Dart_NewSendPort(service_port);
-    Dart_SetReturnValue(arguments, send_port);
-  }
-}
-
-
-// Resolver for the extension library.
-Dart_NativeFunction ResolveName(Dart_Handle name,
-                                int argc,
-                                bool* auto_setup_scope) {
-  const char* c_name;
-  Dart_Handle check_error;
-
-  check_error = Dart_StringToCString(name, &c_name);
-  if (Dart_IsError(check_error)) {
-    Dart_PropagateError(check_error);
-  }
-  if ((strcmp("MDnsExtension_ServicePort", c_name) == 0) && (argc == 0)) {
-    return ServicePort;
-  }
-  return NULL;
-}
-
-
-// Entry point for the extension library.
-DART_EXPORT Dart_Handle mdns_extension_lib_Init(Dart_Handle parent_library) {
-  Dart_Handle result_code;
-  if (Dart_IsError(parent_library)) {
-    return parent_library;
-  }
-
-  result_code = Dart_SetNativeResolver(parent_library, ResolveName, NULL);
-  if (Dart_IsError(result_code)) {
-    return result_code;
-  }
-
-  return parent_library;
-}