runtime/bin/eventhandler_macos.cc - sdk.git - Git at Google

 // 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
 #include <pthread.h>  // NOLINT
 #include <stdio.h>  // NOLINT
 #include <string.h>  // NOLINT
 #include <sys/event.h>  // NOLINT
 #include <unistd.h>  // NOLINT
 #include <fcntl.h>  // NOLINT

 #include "bin/dartutils.h"
 #include "bin/fdutils.h"
 #include "bin/log.h"
 #include "bin/utils.h"
 #include "platform/hashmap.h"
 #include "platform/thread.h"
 #include "platform/utils.h"


 namespace dart {
 namespace bin {

 static const int kInterruptMessageSize = sizeof(InterruptMessage);
 static const int kInfinityTimeout = -1;
 static const int kTimerId = -1;
 static const int kShutdownId = -2;


 bool SocketData::HasReadEvent() {
   return !IsClosedRead() && ((mask_ & (1 << kInEvent)) != 0);
 }


 bool SocketData::HasWriteEvent() {
   return !IsClosedWrite() && ((mask_ & (1 << kOutEvent)) != 0);
 }


 // Unregister the file descriptor for a SocketData structure with kqueue.
 static void RemoveFromKqueue(intptr_t kqueue_fd_, SocketData* sd) {
   static const intptr_t kMaxChanges = 2;
   intptr_t changes = 0;
   struct kevent events[kMaxChanges];
   if (sd->read_tracked_by_kqueue()) {
     EV_SET(events + changes, sd->fd(), EVFILT_READ, EV_DELETE, 0, 0, NULL);
     ++changes;
     sd->set_read_tracked_by_kqueue(false);
   }
   if (sd->write_tracked_by_kqueue()) {
     EV_SET(events + changes, sd->fd(), EVFILT_WRITE, EV_DELETE, 0, 0, sd);
     ++changes;
     sd->set_write_tracked_by_kqueue(false);
   }
   if (changes > 0) {
     ASSERT(changes <= kMaxChanges);
     int status =
       TEMP_FAILURE_RETRY(kevent(kqueue_fd_, events, changes, NULL, 0, NULL));
     if (status == -1) {
       const int kBufferSize = 1024;
       char error_message[kBufferSize];
       strerror_r(errno, error_message, kBufferSize);
       FATAL1("Failed deleting events from kqueue: %s\n", error_message);
     }
   }
 }


 // Update the kqueue registration for SocketData structure to reflect
 // the events currently of interest.
 static void UpdateKqueue(intptr_t kqueue_fd_, SocketData* sd) {
   static const intptr_t kMaxChanges = 2;
   intptr_t changes = 0;
   struct kevent events[kMaxChanges];
   if (sd->port() != 0) {
     // Register or unregister READ filter if needed.
     if (sd->HasReadEvent()) {
       if (!sd->read_tracked_by_kqueue()) {
         EV_SET(events + changes, sd->fd(), EVFILT_READ, EV_ADD, 0, 0, sd);
         ++changes;
         sd->set_read_tracked_by_kqueue(true);
       }
     } else if (sd->read_tracked_by_kqueue()) {
       EV_SET(events + changes, sd->fd(), EVFILT_READ, EV_DELETE, 0, 0, NULL);
       ++changes;
       sd->set_read_tracked_by_kqueue(false);
     }
     // Register or unregister WRITE filter if needed.
     if (sd->HasWriteEvent()) {
       if (!sd->write_tracked_by_kqueue()) {
         EV_SET(events + changes, sd->fd(), EVFILT_WRITE, EV_ADD, 0, 0, sd);
         ++changes;
         sd->set_write_tracked_by_kqueue(true);
       }
     } else if (sd->write_tracked_by_kqueue()) {
       EV_SET(events + changes, sd->fd(), EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
       ++changes;
       sd->set_write_tracked_by_kqueue(false);
     }
   }
   if (changes > 0) {
     ASSERT(changes <= kMaxChanges);
     int status =
       TEMP_FAILURE_RETRY(kevent(kqueue_fd_, events, changes, NULL, 0, NULL));
     if (status == -1) {
       // kQueue does not accept the file descriptor. It could be due to
       // already closed file descriptor, or unuspported devices, such
       // as /dev/null. In such case, mark the file descriptor as closed,
       // so dart will handle it accordingly.
       sd->set_write_tracked_by_kqueue(false);
       sd->set_read_tracked_by_kqueue(false);
       sd->ShutdownRead();
       sd->ShutdownWrite();
       DartUtils::PostInt32(sd->port(), 1 << kCloseEvent);
     }
   }
 }


 EventHandlerImplementation::EventHandlerImplementation()
     : socket_map_(&HashMap::SamePointerValue, 16) {
   intptr_t result;
   result = TEMP_FAILURE_RETRY(pipe(interrupt_fds_));
   if (result != 0) {
     FATAL("Pipe creation failed");
   }
   FDUtils::SetNonBlocking(interrupt_fds_[0]);
   FDUtils::SetCloseOnExec(interrupt_fds_[0]);
   FDUtils::SetCloseOnExec(interrupt_fds_[1]);
   shutdown_ = false;

   kqueue_fd_ = TEMP_FAILURE_RETRY(kqueue());
   if (kqueue_fd_ == -1) {
     FATAL("Failed creating kqueue");
   }
   FDUtils::SetCloseOnExec(kqueue_fd_);
   // Register the interrupt_fd with the kqueue.
   struct kevent event;
   EV_SET(&event, interrupt_fds_[0], EVFILT_READ, EV_ADD, 0, 0, NULL);
   int status = TEMP_FAILURE_RETRY(kevent(kqueue_fd_, &event, 1, NULL, 0, NULL));
   if (status == -1) {
     const int kBufferSize = 1024;
     char error_message[kBufferSize];
     strerror_r(errno, error_message, kBufferSize);
     FATAL1("Failed adding interrupt fd to kqueue: %s\n", error_message);
   }
 }


 EventHandlerImplementation::~EventHandlerImplementation() {
   VOID_TEMP_FAILURE_RETRY(close(kqueue_fd_));
   VOID_TEMP_FAILURE_RETRY(close(interrupt_fds_[0]));
   VOID_TEMP_FAILURE_RETRY(close(interrupt_fds_[1]));
 }


 SocketData* EventHandlerImplementation::GetSocketData(intptr_t fd) {
   ASSERT(fd >= 0);
   HashMap::Entry* entry = socket_map_.Lookup(
       GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd), true);
   ASSERT(entry != NULL);
   SocketData* sd = reinterpret_cast<SocketData*>(entry->value);
   if (sd == NULL) {
     // If there is no data in the hash map for this file descriptor a
     // new SocketData for the file descriptor is inserted.
     sd = new SocketData(fd);
     entry->value = sd;
   }
   ASSERT(fd == sd->fd());
   return sd;
 }


 void EventHandlerImplementation::WakeupHandler(intptr_t id,
                                                Dart_Port dart_port,
                                                int64_t data) {
   InterruptMessage msg;
   msg.id = id;
   msg.dart_port = dart_port;
   msg.data = data;
   // WriteToBlocking will write up to 512 bytes atomically, and since our msg
   // is smaller than 512, we don't need a thread lock.
   ASSERT(kInterruptMessageSize < PIPE_BUF);
   intptr_t result =
       FDUtils::WriteToBlocking(interrupt_fds_[1], &msg, kInterruptMessageSize);
   if (result != kInterruptMessageSize) {
     if (result == -1) {
       perror("Interrupt message failure:");
     }
     FATAL1("Interrupt message failure. Wrote %" Pd " bytes.", result);
   }
 }


 bool EventHandlerImplementation::GetInterruptMessage(InterruptMessage* msg) {
   char* dst = reinterpret_cast<char*>(msg);
   int total_read = 0;
   int bytes_read =
       TEMP_FAILURE_RETRY(read(interrupt_fds_[0], dst, kInterruptMessageSize));
   if (bytes_read < 0) {
     return false;
   }
   total_read = bytes_read;
   while (total_read < kInterruptMessageSize) {
     bytes_read = TEMP_FAILURE_RETRY(read(interrupt_fds_[0],
                                          dst + total_read,
                                          kInterruptMessageSize - total_read));
     if (bytes_read > 0) {
       total_read = total_read + bytes_read;
     }
   }
   return (total_read == kInterruptMessageSize) ? true : false;
 }

 void EventHandlerImplementation::HandleInterruptFd() {
   InterruptMessage msg;
   while (GetInterruptMessage(&msg)) {
     if (msg.id == kTimerId) {
       timeout_queue_.UpdateTimeout(msg.dart_port, msg.data);
     } else if (msg.id == kShutdownId) {
       shutdown_ = true;
     } else {
       SocketData* sd = GetSocketData(msg.id);
       if ((msg.data & (1 << kShutdownReadCommand)) != 0) {
         ASSERT(msg.data == (1 << kShutdownReadCommand));
         // Close the socket for reading.
         sd->ShutdownRead();
         UpdateKqueue(kqueue_fd_, sd);
       } else if ((msg.data & (1 << kShutdownWriteCommand)) != 0) {
         ASSERT(msg.data == (1 << kShutdownWriteCommand));
         // Close the socket for writing.
         sd->ShutdownWrite();
         UpdateKqueue(kqueue_fd_, sd);
       } else if ((msg.data & (1 << kCloseCommand)) != 0) {
         ASSERT(msg.data == (1 << kCloseCommand));
         // Close the socket and free system resources.
         RemoveFromKqueue(kqueue_fd_, sd);
         intptr_t fd = sd->fd();
         if (fd == STDOUT_FILENO) {
           // If stdout, redirect fd to /dev/null.
           int null_fd = TEMP_FAILURE_RETRY(open("/dev/null", O_WRONLY));
           ASSERT(null_fd >= 0);
           VOID_TEMP_FAILURE_RETRY(dup2(null_fd, STDOUT_FILENO));
           VOID_TEMP_FAILURE_RETRY(close(null_fd));
         } else {
           sd->Close();
         }
         socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
         delete sd;
         DartUtils::PostInt32(msg.dart_port, 1 << kDestroyedEvent);
       } else {
         if ((msg.data & (1 << kInEvent)) != 0 && sd->IsClosedRead()) {
           DartUtils::PostInt32(msg.dart_port, 1 << kCloseEvent);
         } else {
           // Setup events to wait for.
           sd->SetPortAndMask(msg.dart_port, msg.data);
           UpdateKqueue(kqueue_fd_, sd);
         }
       }
     }
   }
 }

 #ifdef DEBUG_KQUEUE
 static void PrintEventMask(intptr_t fd, struct kevent* event) {
   Log::Print("%d ", static_cast<int>(fd));
   if (event->filter == EVFILT_READ) Log::Print("EVFILT_READ ");
   if (event->filter == EVFILT_WRITE) Log::Print("EVFILT_WRITE ");
   Log::Print("flags: %x: ", event->flags);
   if ((event->flags & EV_EOF) != 0) Log::Print("EV_EOF ");
   if ((event->flags & EV_ERROR) != 0) Log::Print("EV_ERROR ");
   Log::Print("- fflags: %d ", event->fflags);
   Log::Print("(available %d) ",
       static_cast<int>(FDUtils::AvailableBytes(fd)));
   Log::Print("\n");
 }
 #endif


 intptr_t EventHandlerImplementation::GetEvents(struct kevent* event,
                                                SocketData* sd) {
 #ifdef DEBUG_KQUEUE
   PrintEventMask(sd->fd(), event);
 #endif
   intptr_t event_mask = 0;
   if (sd->IsListeningSocket()) {
     // On a listening socket the READ event means that there are
     // connections ready to be accepted.
     if (event->filter == EVFILT_READ) {
       if ((event->flags & EV_EOF) != 0) {
         if (event->fflags != 0) {
           event_mask |= (1 << kErrorEvent);
         } else {
           event_mask |= (1 << kCloseEvent);
         }
       }
       if (event_mask == 0) event_mask |= (1 << kInEvent);
     } else {
       UNREACHABLE();
     }
   } else {
     // Prioritize data events over close and error events.
     if (event->filter == EVFILT_READ) {
       if (FDUtils::AvailableBytes(sd->fd()) != 0) {
          event_mask = (1 << kInEvent);
       } else if ((event->flags & EV_EOF) != 0) {
         if (event->fflags != 0) {
           event_mask |= (1 << kErrorEvent);
         } else {
           event_mask |= (1 << kCloseEvent);
         }
         sd->MarkClosedRead();
       }
     } else if (event->filter == EVFILT_WRITE) {
       if ((event->flags & EV_EOF) != 0) {
         if (event->fflags != 0) {
           event_mask |= (1 << kErrorEvent);
         } else {
           event_mask |= (1 << kCloseEvent);
         }
         // If the receiver closed for reading, close for writing,
         // update the registration with kqueue, and do not report a
         // write event.
         sd->MarkClosedWrite();
         UpdateKqueue(kqueue_fd_, sd);
       } else {
         event_mask |= (1 << kOutEvent);
       }
     } else {
       UNREACHABLE();
     }
   }

   return event_mask;
 }


 void EventHandlerImplementation::HandleEvents(struct kevent* events,
                                               int size) {
   for (int i = 0; i < size; i++) {
     // If flag EV_ERROR is set it indicates an error in kevent processing.
     if ((events[i].flags & EV_ERROR) != 0) {
       const int kBufferSize = 1024;
       char error_message[kBufferSize];
       strerror_r(events[i].data, error_message, kBufferSize);
       FATAL1("kevent failed %s\n", error_message);
     }
     if (events[i].udata != NULL) {
       SocketData* sd = reinterpret_cast<SocketData*>(events[i].udata);
       intptr_t event_mask = GetEvents(events + i, sd);
       if (event_mask != 0) {
         // Unregister events for the file descriptor. Events will be
         // registered again when the current event has been handled in
         // Dart code.
         RemoveFromKqueue(kqueue_fd_, sd);
         Dart_Port port = sd->port();
         ASSERT(port != 0);
         DartUtils::PostInt32(port, event_mask);
       }
     }
   }
   HandleInterruptFd();
 }


 int64_t EventHandlerImplementation::GetTimeout() {
   if (!timeout_queue_.HasTimeout()) {
     return kInfinityTimeout;
   }
   int64_t millis = timeout_queue_.CurrentTimeout() -
       TimerUtils::GetCurrentTimeMilliseconds();
   return (millis < 0) ? 0 : millis;
 }


 void EventHandlerImplementation::HandleTimeout() {
   if (timeout_queue_.HasTimeout()) {
     int64_t millis = timeout_queue_.CurrentTimeout() -
         TimerUtils::GetCurrentTimeMilliseconds();
     if (millis <= 0) {
       DartUtils::PostNull(timeout_queue_.CurrentPort());
       timeout_queue_.RemoveCurrent();
     }
   }
 }


 void EventHandlerImplementation::EventHandlerEntry(uword args) {
   static const intptr_t kMaxEvents = 16;
   struct kevent events[kMaxEvents];
   EventHandler* handler = reinterpret_cast<EventHandler*>(args);
   EventHandlerImplementation* handler_impl = &handler->delegate_;
   ASSERT(handler_impl != NULL);
   while (!handler_impl->shutdown_) {
     int64_t millis = handler_impl->GetTimeout();
     ASSERT(millis == kInfinityTimeout || millis >= 0);
     if (millis > kMaxInt32) millis = kMaxInt32;
     // NULL pointer timespec for infinite timeout.
     ASSERT(kInfinityTimeout < 0);
     struct timespec* timeout = NULL;
     struct timespec ts;
     if (millis >= 0) {
       ts.tv_sec = millis / 1000;
       ts.tv_nsec = (millis - (ts.tv_sec * 1000)) * 1000000;
       timeout = &ts;
     }
     intptr_t result = TEMP_FAILURE_RETRY(kevent(handler_impl->kqueue_fd_,
                                                 NULL,
                                                 0,
                                                 events,
                                                 kMaxEvents,
                                                 timeout));
     if (result == -1) {
       const int kBufferSize = 1024;
       char error_message[kBufferSize];
       strerror_r(errno, error_message, kBufferSize);
       FATAL1("kevent failed %s\n", error_message);
     } else {
       handler_impl->HandleTimeout();
       handler_impl->HandleEvents(events, result);
     }
   }
   delete handler;
 }


 void EventHandlerImplementation::Start(EventHandler* handler) {
   int result =
       dart::Thread::Start(&EventHandlerImplementation::EventHandlerEntry,
                           reinterpret_cast<uword>(handler));
   if (result != 0) {
     FATAL1("Failed to start event handler thread %d", result);
   }
 }


 void EventHandlerImplementation::Shutdown() {
   SendData(kShutdownId, 0, 0);
 }


 void EventHandlerImplementation::SendData(intptr_t id,
                                           Dart_Port dart_port,
                                           int64_t data) {
   WakeupHandler(id, dart_port, data);
 }


 void* EventHandlerImplementation::GetHashmapKeyFromFd(intptr_t fd) {
   // The hashmap does not support keys with value 0.
   return reinterpret_cast<void*>(fd + 1);
 }


 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)
	// 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
	#include <pthread.h> // NOLINT
	#include <stdio.h> // NOLINT
	#include <string.h> // NOLINT
	#include <sys/event.h> // NOLINT
	#include <unistd.h> // NOLINT
	#include <fcntl.h> // NOLINT

	#include "bin/dartutils.h"
	#include "bin/fdutils.h"
	#include "bin/log.h"
	#include "bin/utils.h"
	#include "platform/hashmap.h"
	#include "platform/thread.h"
	#include "platform/utils.h"


	namespace dart {
	namespace bin {

	static const int kInterruptMessageSize = sizeof(InterruptMessage);
	static const int kInfinityTimeout = -1;
	static const int kTimerId = -1;
	static const int kShutdownId = -2;


	bool SocketData::HasReadEvent() {
	return !IsClosedRead() && ((mask_ & (1 << kInEvent)) != 0);
	}


	bool SocketData::HasWriteEvent() {
	return !IsClosedWrite() && ((mask_ & (1 << kOutEvent)) != 0);
	}


	// Unregister the file descriptor for a SocketData structure with kqueue.
	static void RemoveFromKqueue(intptr_t kqueue_fd_, SocketData* sd) {
	static const intptr_t kMaxChanges = 2;
	intptr_t changes = 0;
	struct kevent events[kMaxChanges];
	if (sd->read_tracked_by_kqueue()) {
	EV_SET(events + changes, sd->fd(), EVFILT_READ, EV_DELETE, 0, 0, NULL);
	++changes;
	sd->set_read_tracked_by_kqueue(false);
	}
	if (sd->write_tracked_by_kqueue()) {
	EV_SET(events + changes, sd->fd(), EVFILT_WRITE, EV_DELETE, 0, 0, sd);
	++changes;
	sd->set_write_tracked_by_kqueue(false);
	}
	if (changes > 0) {
	ASSERT(changes <= kMaxChanges);
	int status =
	TEMP_FAILURE_RETRY(kevent(kqueue_fd_, events, changes, NULL, 0, NULL));
	if (status == -1) {
	const int kBufferSize = 1024;
	char error_message[kBufferSize];
	strerror_r(errno, error_message, kBufferSize);
	FATAL1("Failed deleting events from kqueue: %s\n", error_message);
	}
	}
	}


	// Update the kqueue registration for SocketData structure to reflect
	// the events currently of interest.
	static void UpdateKqueue(intptr_t kqueue_fd_, SocketData* sd) {
	static const intptr_t kMaxChanges = 2;
	intptr_t changes = 0;
	struct kevent events[kMaxChanges];
	if (sd->port() != 0) {
	// Register or unregister READ filter if needed.
	if (sd->HasReadEvent()) {
	if (!sd->read_tracked_by_kqueue()) {
	EV_SET(events + changes, sd->fd(), EVFILT_READ, EV_ADD, 0, 0, sd);
	++changes;
	sd->set_read_tracked_by_kqueue(true);
	}
	} else if (sd->read_tracked_by_kqueue()) {
	EV_SET(events + changes, sd->fd(), EVFILT_READ, EV_DELETE, 0, 0, NULL);
	++changes;
	sd->set_read_tracked_by_kqueue(false);
	}
	// Register or unregister WRITE filter if needed.
	if (sd->HasWriteEvent()) {
	if (!sd->write_tracked_by_kqueue()) {
	EV_SET(events + changes, sd->fd(), EVFILT_WRITE, EV_ADD, 0, 0, sd);
	++changes;
	sd->set_write_tracked_by_kqueue(true);
	}
	} else if (sd->write_tracked_by_kqueue()) {
	EV_SET(events + changes, sd->fd(), EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
	++changes;
	sd->set_write_tracked_by_kqueue(false);
	}
	}
	if (changes > 0) {
	ASSERT(changes <= kMaxChanges);
	int status =
	TEMP_FAILURE_RETRY(kevent(kqueue_fd_, events, changes, NULL, 0, NULL));
	if (status == -1) {
	// kQueue does not accept the file descriptor. It could be due to
	// already closed file descriptor, or unuspported devices, such
	// as /dev/null. In such case, mark the file descriptor as closed,
	// so dart will handle it accordingly.
	sd->set_write_tracked_by_kqueue(false);
	sd->set_read_tracked_by_kqueue(false);
	sd->ShutdownRead();
	sd->ShutdownWrite();
	DartUtils::PostInt32(sd->port(), 1 << kCloseEvent);
	}
	}
	}


	EventHandlerImplementation::EventHandlerImplementation()
	: socket_map_(&HashMap::SamePointerValue, 16) {
	intptr_t result;
	result = TEMP_FAILURE_RETRY(pipe(interrupt_fds_));
	if (result != 0) {
	FATAL("Pipe creation failed");
	}
	FDUtils::SetNonBlocking(interrupt_fds_[0]);
	FDUtils::SetCloseOnExec(interrupt_fds_[0]);
	FDUtils::SetCloseOnExec(interrupt_fds_[1]);
	shutdown_ = false;

	kqueue_fd_ = TEMP_FAILURE_RETRY(kqueue());
	if (kqueue_fd_ == -1) {
	FATAL("Failed creating kqueue");
	}
	FDUtils::SetCloseOnExec(kqueue_fd_);
	// Register the interrupt_fd with the kqueue.
	struct kevent event;
	EV_SET(&event, interrupt_fds_[0], EVFILT_READ, EV_ADD, 0, 0, NULL);
	int status = TEMP_FAILURE_RETRY(kevent(kqueue_fd_, &event, 1, NULL, 0, NULL));
	if (status == -1) {
	const int kBufferSize = 1024;
	char error_message[kBufferSize];
	strerror_r(errno, error_message, kBufferSize);
	FATAL1("Failed adding interrupt fd to kqueue: %s\n", error_message);
	}
	}


	EventHandlerImplementation::~EventHandlerImplementation() {
	VOID_TEMP_FAILURE_RETRY(close(kqueue_fd_));
	VOID_TEMP_FAILURE_RETRY(close(interrupt_fds_[0]));
	VOID_TEMP_FAILURE_RETRY(close(interrupt_fds_[1]));
	}


	SocketData* EventHandlerImplementation::GetSocketData(intptr_t fd) {
	ASSERT(fd >= 0);
	HashMap::Entry* entry = socket_map_.Lookup(
	GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd), true);
	ASSERT(entry != NULL);
	SocketData* sd = reinterpret_cast<SocketData*>(entry->value);
	if (sd == NULL) {
	// If there is no data in the hash map for this file descriptor a
	// new SocketData for the file descriptor is inserted.
	sd = new SocketData(fd);
	entry->value = sd;
	}
	ASSERT(fd == sd->fd());
	return sd;
	}


	void EventHandlerImplementation::WakeupHandler(intptr_t id,
	Dart_Port dart_port,
	int64_t data) {
	InterruptMessage msg;
	msg.id = id;
	msg.dart_port = dart_port;
	msg.data = data;
	// WriteToBlocking will write up to 512 bytes atomically, and since our msg
	// is smaller than 512, we don't need a thread lock.
	ASSERT(kInterruptMessageSize < PIPE_BUF);
	intptr_t result =
	FDUtils::WriteToBlocking(interrupt_fds_[1], &msg, kInterruptMessageSize);
	if (result != kInterruptMessageSize) {
	if (result == -1) {
	perror("Interrupt message failure:");
	}
	FATAL1("Interrupt message failure. Wrote %" Pd " bytes.", result);
	}
	}


	bool EventHandlerImplementation::GetInterruptMessage(InterruptMessage* msg) {
	char* dst = reinterpret_cast<char*>(msg);
	int total_read = 0;
	int bytes_read =
	TEMP_FAILURE_RETRY(read(interrupt_fds_[0], dst, kInterruptMessageSize));
	if (bytes_read < 0) {
	return false;
	}
	total_read = bytes_read;
	while (total_read < kInterruptMessageSize) {
	bytes_read = TEMP_FAILURE_RETRY(read(interrupt_fds_[0],
	dst + total_read,
	kInterruptMessageSize - total_read));
	if (bytes_read > 0) {
	total_read = total_read + bytes_read;
	}
	}
	return (total_read == kInterruptMessageSize) ? true : false;
	}

	void EventHandlerImplementation::HandleInterruptFd() {
	InterruptMessage msg;
	while (GetInterruptMessage(&msg)) {
	if (msg.id == kTimerId) {
	timeout_queue_.UpdateTimeout(msg.dart_port, msg.data);
	} else if (msg.id == kShutdownId) {
	shutdown_ = true;
	} else {
	SocketData* sd = GetSocketData(msg.id);
	if ((msg.data & (1 << kShutdownReadCommand)) != 0) {
	ASSERT(msg.data == (1 << kShutdownReadCommand));
	// Close the socket for reading.
	sd->ShutdownRead();
	UpdateKqueue(kqueue_fd_, sd);
	} else if ((msg.data & (1 << kShutdownWriteCommand)) != 0) {
	ASSERT(msg.data == (1 << kShutdownWriteCommand));
	// Close the socket for writing.
	sd->ShutdownWrite();
	UpdateKqueue(kqueue_fd_, sd);
	} else if ((msg.data & (1 << kCloseCommand)) != 0) {
	ASSERT(msg.data == (1 << kCloseCommand));
	// Close the socket and free system resources.
	RemoveFromKqueue(kqueue_fd_, sd);
	intptr_t fd = sd->fd();
	if (fd == STDOUT_FILENO) {
	// If stdout, redirect fd to /dev/null.
	int null_fd = TEMP_FAILURE_RETRY(open("/dev/null", O_WRONLY));
	ASSERT(null_fd >= 0);
	VOID_TEMP_FAILURE_RETRY(dup2(null_fd, STDOUT_FILENO));
	VOID_TEMP_FAILURE_RETRY(close(null_fd));
	} else {
	sd->Close();
	}
	socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
	delete sd;
	DartUtils::PostInt32(msg.dart_port, 1 << kDestroyedEvent);
	} else {
	if ((msg.data & (1 << kInEvent)) != 0 && sd->IsClosedRead()) {
	DartUtils::PostInt32(msg.dart_port, 1 << kCloseEvent);
	} else {
	// Setup events to wait for.
	sd->SetPortAndMask(msg.dart_port, msg.data);
	UpdateKqueue(kqueue_fd_, sd);
	}
	}
	}
	}
	}

	#ifdef DEBUG_KQUEUE
	static void PrintEventMask(intptr_t fd, struct kevent* event) {
	Log::Print("%d ", static_cast<int>(fd));
	if (event->filter == EVFILT_READ) Log::Print("EVFILT_READ ");
	if (event->filter == EVFILT_WRITE) Log::Print("EVFILT_WRITE ");
	Log::Print("flags: %x: ", event->flags);
	if ((event->flags & EV_EOF) != 0) Log::Print("EV_EOF ");
	if ((event->flags & EV_ERROR) != 0) Log::Print("EV_ERROR ");
	Log::Print("- fflags: %d ", event->fflags);
	Log::Print("(available %d) ",
	static_cast<int>(FDUtils::AvailableBytes(fd)));
	Log::Print("\n");
	}
	#endif


	intptr_t EventHandlerImplementation::GetEvents(struct kevent* event,
	SocketData* sd) {
	#ifdef DEBUG_KQUEUE
	PrintEventMask(sd->fd(), event);
	#endif
	intptr_t event_mask = 0;
	if (sd->IsListeningSocket()) {
	// On a listening socket the READ event means that there are
	// connections ready to be accepted.
	if (event->filter == EVFILT_READ) {
	if ((event->flags & EV_EOF) != 0) {
	if (event->fflags != 0) {
	event_mask \|= (1 << kErrorEvent);
	} else {
	event_mask \|= (1 << kCloseEvent);
	}
	}
	if (event_mask == 0) event_mask \|= (1 << kInEvent);
	} else {
	UNREACHABLE();
	}
	} else {
	// Prioritize data events over close and error events.
	if (event->filter == EVFILT_READ) {
	if (FDUtils::AvailableBytes(sd->fd()) != 0) {
	event_mask = (1 << kInEvent);
	} else if ((event->flags & EV_EOF) != 0) {
	if (event->fflags != 0) {
	event_mask \|= (1 << kErrorEvent);
	} else {
	event_mask \|= (1 << kCloseEvent);
	}
	sd->MarkClosedRead();
	}
	} else if (event->filter == EVFILT_WRITE) {
	if ((event->flags & EV_EOF) != 0) {
	if (event->fflags != 0) {
	event_mask \|= (1 << kErrorEvent);
	} else {
	event_mask \|= (1 << kCloseEvent);
	}
	// If the receiver closed for reading, close for writing,
	// update the registration with kqueue, and do not report a
	// write event.
	sd->MarkClosedWrite();
	UpdateKqueue(kqueue_fd_, sd);
	} else {
	event_mask \|= (1 << kOutEvent);
	}
	} else {
	UNREACHABLE();
	}
	}

	return event_mask;
	}


	void EventHandlerImplementation::HandleEvents(struct kevent* events,
	int size) {
	for (int i = 0; i < size; i++) {
	// If flag EV_ERROR is set it indicates an error in kevent processing.
	if ((events[i].flags & EV_ERROR) != 0) {
	const int kBufferSize = 1024;
	char error_message[kBufferSize];
	strerror_r(events[i].data, error_message, kBufferSize);
	FATAL1("kevent failed %s\n", error_message);
	}
	if (events[i].udata != NULL) {
	SocketData* sd = reinterpret_cast<SocketData*>(events[i].udata);
	intptr_t event_mask = GetEvents(events + i, sd);
	if (event_mask != 0) {
	// Unregister events for the file descriptor. Events will be
	// registered again when the current event has been handled in
	// Dart code.
	RemoveFromKqueue(kqueue_fd_, sd);
	Dart_Port port = sd->port();
	ASSERT(port != 0);
	DartUtils::PostInt32(port, event_mask);
	}
	}
	}
	HandleInterruptFd();
	}


	int64_t EventHandlerImplementation::GetTimeout() {
	if (!timeout_queue_.HasTimeout()) {
	return kInfinityTimeout;
	}
	int64_t millis = timeout_queue_.CurrentTimeout() -
	TimerUtils::GetCurrentTimeMilliseconds();
	return (millis < 0) ? 0 : millis;
	}


	void EventHandlerImplementation::HandleTimeout() {
	if (timeout_queue_.HasTimeout()) {
	int64_t millis = timeout_queue_.CurrentTimeout() -
	TimerUtils::GetCurrentTimeMilliseconds();
	if (millis <= 0) {
	DartUtils::PostNull(timeout_queue_.CurrentPort());
	timeout_queue_.RemoveCurrent();
	}
	}
	}


	void EventHandlerImplementation::EventHandlerEntry(uword args) {
	static const intptr_t kMaxEvents = 16;
	struct kevent events[kMaxEvents];
	EventHandler* handler = reinterpret_cast<EventHandler*>(args);
	EventHandlerImplementation* handler_impl = &handler->delegate_;
	ASSERT(handler_impl != NULL);
	while (!handler_impl->shutdown_) {
	int64_t millis = handler_impl->GetTimeout();
	ASSERT(millis == kInfinityTimeout \|\| millis >= 0);
	if (millis > kMaxInt32) millis = kMaxInt32;
	// NULL pointer timespec for infinite timeout.
	ASSERT(kInfinityTimeout < 0);
	struct timespec* timeout = NULL;
	struct timespec ts;
	if (millis >= 0) {
	ts.tv_sec = millis / 1000;
	ts.tv_nsec = (millis - (ts.tv_sec * 1000)) * 1000000;
	timeout = &ts;
	}
	intptr_t result = TEMP_FAILURE_RETRY(kevent(handler_impl->kqueue_fd_,
	NULL,
	0,
	events,
	kMaxEvents,
	timeout));
	if (result == -1) {
	const int kBufferSize = 1024;
	char error_message[kBufferSize];
	strerror_r(errno, error_message, kBufferSize);
	FATAL1("kevent failed %s\n", error_message);
	} else {
	handler_impl->HandleTimeout();
	handler_impl->HandleEvents(events, result);
	}
	}
	delete handler;
	}


	void EventHandlerImplementation::Start(EventHandler* handler) {
	int result =
	dart::Thread::Start(&EventHandlerImplementation::EventHandlerEntry,
	reinterpret_cast<uword>(handler));
	if (result != 0) {
	FATAL1("Failed to start event handler thread %d", result);
	}
	}


	void EventHandlerImplementation::Shutdown() {
	SendData(kShutdownId, 0, 0);
	}


	void EventHandlerImplementation::SendData(intptr_t id,
	Dart_Port dart_port,
	int64_t data) {
	WakeupHandler(id, dart_port, data);
	}


	void* EventHandlerImplementation::GetHashmapKeyFromFd(intptr_t fd) {
	// The hashmap does not support keys with value 0.
	return reinterpret_cast<void*>(fd + 1);
	}


	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)