Make server-sockets level triggered.

runtime/bin/eventhandler_macos.cc

 // Copyright (c) 2012, 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_MACOS)
 
 #include "bin/eventhandler.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 45 matching lines @@
 }
 
 
 // Update the kqueue registration for SocketData structure to reflect
 // the events currently of interest.
 static void AddToKqueue(intptr_t kqueue_fd_, SocketData* sd) {
   ASSERT(!sd->tracked_by_kqueue());
   static const intptr_t kMaxChanges = 2;
   intptr_t changes = 0;
   struct kevent events[kMaxChanges];
+  int flags = EV_ADD;
+  if (!sd->IsListeningSocket()) {
+    flags |= EV_CLEAR;
+  }
   // Register or unregister READ filter if needed.
   if (sd->HasReadEvent()) {
     EV_SET(events + changes,
            sd->fd(),
            EVFILT_READ,
-           EV_ADD | EV_CLEAR,
+           flags,
            0,
            0,
            sd);
     ++changes;
   }
   // Register or unregister WRITE filter if needed.
   if (sd->HasWriteEvent()) {
     EV_SET(events + changes,
            sd->fd(),
            EVFILT_WRITE,
-           EV_ADD | EV_CLEAR,
+           flags,
            0,
            0,
            sd);
     ++changes;
   }
   ASSERT(changes > 0);
   ASSERT(changes <= kMaxChanges);
   int status =
       NO_RETRY_EXPECTED(kevent(kqueue_fd_, events, changes, NULL, 0, NULL));
   if (status == -1) {
@@ skipping 210 matching lines @@
       char error_message[kBufferSize];
       strerror_r(events[i].data, error_message, kBufferSize);
       FATAL1("kevent failed %s\n", error_message);
     }
     if (events[i].udata == NULL) {
       interrupt_seen = true;
     } else {
       SocketData* sd = reinterpret_cast<SocketData*>(events[i].udata);
       intptr_t event_mask = GetEvents(events + i, sd);
       if (event_mask != 0) {
-        if (!sd->IsListeningSocket() && sd->TakeToken()) {
+        if (sd->TakeToken()) {
           // Took last token, remove from epoll.
           RemoveFromKqueue(kqueue_fd_, sd);
         }
         Dart_Port port = sd->port();
         ASSERT(port != 0);
         DartUtils::PostInt32(port, event_mask);
       }
     }
   }
   if (interrupt_seen) {
@@ skipping 95 matching lines @@
 
 uint32_t EventHandlerImplementation::GetHashmapHashFromFd(intptr_t fd) {
   // The hashmap does not support keys with value 0.
   return dart::Utils::WordHash(fd + 1);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)