Add reusePort argument to ServerSocket.

runtime/bin/socket_win.cc

 // Copyright (c) 2013, the Dart 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 file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/builtin.h"
 #include "bin/eventhandler.h"
 #include "bin/file.h"
@@ skipping 319 matching lines @@
     }
   }
   free(addrs);
   return addresses;
 }
 
 
 intptr_t ServerSocket::CreateBindListen(RawAddr addr,
                                         intptr_t port,
                                         intptr_t backlog,
-                                        bool v6_only) {
+                                        bool v6_only,
+                                        bool reuse_port) {
   SOCKET s = socket(addr.ss.ss_family, SOCK_STREAM, IPPROTO_TCP);
   if (s == INVALID_SOCKET) {
     return -1;
   }
 
   BOOL optval = true;
-  int status = setsockopt(s,
-                          SOL_SOCKET,
-                          SO_EXCLUSIVEADDRUSE,
-                          reinterpret_cast<const char*>(&optval),
-                          sizeof(optval));
+  int status;
+  if (reuse_port) {
+    status = setsockopt(s,
+                        SOL_SOCKET,
+                        SO_REUSEADDR,
+                        reinterpret_cast<const char*>(&optval),
+                        sizeof(optval));
+  } else {
+    status = setsockopt(s,
+                        SOL_SOCKET,
+                        SO_EXCLUSIVEADDRUSE,
+                        reinterpret_cast<const char*>(&optval),
+                        sizeof(optval));
+  }
   if (status == SOCKET_ERROR) {
     DWORD rc = WSAGetLastError();
     closesocket(s);
     SetLastError(rc);
     return -1;
   }
 
   if (addr.ss.ss_family == AF_INET6) {
     optval = v6_only;
     setsockopt(s,
@@ skipping 77 matching lines @@
                     IPPROTO_TCP,
                     TCP_NODELAY,
                     reinterpret_cast<char *>(&on),
                     sizeof(on)) == 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)