Remove SocketData and now only pass the dart port to epoll.

runtime/bin/eventhandler_linux.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_LINUX)
 
 #include "bin/eventhandler.h"
 
 #include <errno.h>  // NOLINT
 #include <pthread.h>  // NOLINT
 #include <stdio.h>  // NOLINT
 #include <string.h>  // NOLINT
 #include <sys/epoll.h>  // NOLINT
 #include <sys/stat.h>  // NOLINT
 #include <sys/timerfd.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 "bin/socket.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 kTimerId = -1;
-static const int kShutdownId = -2;
 
 
-// Unregister the file descriptor for a SocketData structure with epoll.
-static void RemoveFromEpollInstance(intptr_t epoll_fd_, SocketData* sd) {
-  if (!sd->tracked_by_epoll()) return;
-  int status = TEMP_FAILURE_RETRY(epoll_ctl(epoll_fd_,
-                                            EPOLL_CTL_DEL,
-                                            sd->fd(),
-                                            NULL));
-  if (status == -1) {
-    FATAL("Failed unregistering events for file descriptor");
-  }
-  sd->set_tracked_by_epoll(false);
-}
-
-
-static void AddToEpollInstance(intptr_t epoll_fd_, SocketData* sd, int mask) {
-  ASSERT(!sd->tracked_by_epoll());
+static void AddToEpollInstance(intptr_t epoll_fd_,
+                               int fd, Dart_Port port,
+                               int mask) {
   struct epoll_event event;
   event.events = EPOLLET | EPOLLRDHUP;
   if ((mask & (1 << kInEvent)) != 0) event.events |= EPOLLIN;
   if ((mask & (1 << kOutEvent)) != 0) event.events |= EPOLLOUT;
-  event.data.ptr = sd;
+  // Be sure we don't collide with the TIMER_BIT.
+  if (port == ILLEGAL_PORT) {
+    FATAL("Illigal port sent to event handler");
+  }
+  event.data.u64 = port;
   int status = TEMP_FAILURE_RETRY(epoll_ctl(epoll_fd_,
                                             EPOLL_CTL_ADD,
-                                            sd->fd(),
+                                            fd,
                                             &event));
   if (status == -1) {
     // Epoll 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.
-    DartUtils::PostInt32(sd->port(), 1 << kCloseEvent);
-  } else {
-    sd->set_tracked_by_epoll(true);
+    DartUtils::PostInt32(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;
+EventHandlerImplementation::EventHandlerImplementation() : shutdown_(false) {
   // The initial size passed to epoll_create is ignore on newer (>=
   // 2.6.8) Linux versions
   static const int kEpollInitialSize = 64;
   epoll_fd_ = TEMP_FAILURE_RETRY(epoll_create(kEpollInitialSize));
   if (epoll_fd_ == -1) {
     FATAL("Failed creating epoll file descriptor");
   }
   FDUtils::SetCloseOnExec(epoll_fd_);
-  // Register the interrupt_fd with the epoll instance.
-  struct epoll_event event;
-  event.events = EPOLLIN;
-  event.data.ptr = NULL;
-  int status = TEMP_FAILURE_RETRY(epoll_ctl(epoll_fd_,
-                                            EPOLL_CTL_ADD,
-                                            interrupt_fds_[0],
-                                            &event));
-  if (status == -1) {
-    FATAL("Failed adding interrupt fd to epoll instance");
-  }
   timer_fd_ = TEMP_FAILURE_RETRY(timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC));
   if (epoll_fd_ == -1) {
     FATAL("Failed creating timerfd file descriptor");
   }
   // Register the timer_fd_ with the epoll instance.
+  struct epoll_event event;
   event.events = EPOLLIN;
-  event.data.fd = timer_fd_;
-  status = TEMP_FAILURE_RETRY(epoll_ctl(epoll_fd_,
-                                        EPOLL_CTL_ADD,
-                                        timer_fd_,
-                                        &event));
+  event.data.u64 = ILLEGAL_PORT;  // Use ILLEGAL_PORT to identify timer-fd.
+  int status = TEMP_FAILURE_RETRY(epoll_ctl(epoll_fd_,
+                                            EPOLL_CTL_ADD,
+                                            timer_fd_,
+                                            &event));
   if (status == -1) {
     FATAL2(
         "Failed adding timerfd fd(%i) to epoll instance: %i", timer_fd_, errno);
   }
 }
 
 
 EventHandlerImplementation::~EventHandlerImplementation() {
   TEMP_FAILURE_RETRY(close(epoll_fd_));
   TEMP_FAILURE_RETRY(close(timer_fd_));
-  TEMP_FAILURE_RETRY(close(interrupt_fds_[0]));
-  TEMP_FAILURE_RETRY(close(interrupt_fds_[1]));
-}
-
-
-SocketData* EventHandlerImplementation::GetSocketData(intptr_t fd,
-                                                      bool* is_new) {
-  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;
-    *is_new = true;
-  }
-  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.
-  // See: http://linux.die.net/man/7/pipe, section 'Pipe_buf'.
-  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);
-  }
-}
-
-
-void EventHandlerImplementation::HandleInterruptFd() {
-  const intptr_t MAX_MESSAGES = kInterruptMessageSize;
-  InterruptMessage msg[MAX_MESSAGES];
-  ssize_t bytes = TEMP_FAILURE_RETRY(
-      read(interrupt_fds_[0], msg, MAX_MESSAGES * kInterruptMessageSize));
-  for (ssize_t i = 0; i < bytes / kInterruptMessageSize; i++) {
-    if (msg[i].id == kTimerId) {
-      timeout_queue_.UpdateTimeout(msg[i].dart_port, msg[i].data);
-      struct itimerspec it;
-      memset(&it, 0, sizeof(it));
-      if (timeout_queue_.HasTimeout()) {
-        int64_t millis = timeout_queue_.CurrentTimeout();
-        it.it_value.tv_sec = millis / 1000;
-        it.it_value.tv_nsec = (millis % 1000) * 1000000;
-      }
-      timerfd_settime(timer_fd_, TFD_TIMER_ABSTIME, &it, NULL);
-    } else if (msg[i].id == kShutdownId) {
-      shutdown_ = true;
-    } else {
-      bool is_new = false;
-      SocketData* sd = GetSocketData(msg[i].id, &is_new);
-      if (is_new) {
-        sd->SetPort(msg[i].dart_port);
-        AddToEpollInstance(epoll_fd_, sd, msg[i].data);
-      }
-      if ((msg[i].data & (1 << kShutdownReadCommand)) != 0) {
-        ASSERT(msg[i].data == (1 << kShutdownReadCommand));
-        // Close the socket for reading.
-        sd->ShutdownRead();
-      } else if ((msg[i].data & (1 << kShutdownWriteCommand)) != 0) {
-        ASSERT(msg[i].data == (1 << kShutdownWriteCommand));
-        // Close the socket for writing.
-        sd->ShutdownWrite();
-      } else if ((msg[i].data & (1 << kCloseCommand)) != 0) {
-        ASSERT(msg[i].data == (1 << kCloseCommand));
-        // Close the socket and free system resources and move on to
-        // next message.
-        RemoveFromEpollInstance(epoll_fd_, sd);
-        intptr_t fd = sd->fd();
-        sd->Close();
-        socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
-        delete sd;
-        DartUtils::PostInt32(msg[i].dart_port, 1 << kDestroyedEvent);
-      }
-    }
-  }
 }
 
 #ifdef DEBUG_POLL
-static void PrintEventMask(intptr_t fd, intptr_t events) {
-  Log::Print("%d ", fd);
+static void PrintEventMask(intptr_t events) {
+  // TODO(ajohnsen): When DEBUG_POLL is enabled, we could add the fd to the
+  // epoll-data as well.
   if ((events & EPOLLIN) != 0) Log::Print("EPOLLIN ");
   if ((events & EPOLLPRI) != 0) Log::Print("EPOLLPRI ");
   if ((events & EPOLLOUT) != 0) Log::Print("EPOLLOUT ");
   if ((events & EPOLLERR) != 0) Log::Print("EPOLLERR ");
   if ((events & EPOLLHUP) != 0) Log::Print("EPOLLHUP ");
   if ((events & EPOLLRDHUP) != 0) Log::Print("EPOLLRDHUP ");
   int all_events = EPOLLIN | EPOLLPRI | EPOLLOUT |
       EPOLLERR | EPOLLHUP | EPOLLRDHUP;
   if ((events & ~all_events) != 0) {
     Log::Print("(and %08x) ", events & ~all_events);
   }
-  Log::Print("(available %d) ", FDUtils::AvailableBytes(fd));
 
   Log::Print("\n");
 }
 #endif
 
-intptr_t EventHandlerImplementation::GetPollEvents(intptr_t events,
-                                                   SocketData* sd) {
+intptr_t EventHandlerImplementation::GetPollEvents(intptr_t events) {
 #ifdef DEBUG_POLL
-  PrintEventMask(sd->fd(), events);
+  PrintEventMask(events);
 #endif
   if (events & EPOLLERR) {
     // Return only error if EPOLLIN is present.
     return (events & EPOLLIN) ? (1 << kErrorEvent) : 0;
   }
   intptr_t event_mask = 0;
   if (events & EPOLLIN) event_mask |= (1 << kInEvent);
   if (events & EPOLLOUT) event_mask |= (1 << kOutEvent);
   if (events & (EPOLLHUP | EPOLLRDHUP)) event_mask |= (1 << kCloseEvent);
   return event_mask;
 }
 
 
 void EventHandlerImplementation::HandleEvents(struct epoll_event* events,
                                               int size) {
-  bool interrupt_seen = false;
   for (int i = 0; i < size; i++) {
-    if (events[i].data.ptr == NULL) {
-      interrupt_seen = true;
-    } else if (events[i].data.fd == timer_fd_) {
+    uint64_t data = events[i].data.u64;
+    if (data == ILLEGAL_PORT) {
       int64_t val;
       VOID_TEMP_FAILURE_RETRY(read(timer_fd_, &val, sizeof(val)));
       if (timeout_queue_.HasTimeout()) {
         DartUtils::PostNull(timeout_queue_.CurrentPort());
         timeout_queue_.RemoveCurrent();
       }
     } else {
-      SocketData* sd = reinterpret_cast<SocketData*>(events[i].data.ptr);
-      int32_t event_mask = GetPollEvents(events[i].events, sd);
+      int32_t event_mask = GetPollEvents(events[i].events);
       if (event_mask != 0) {
-        Dart_Port port = sd->port();
+        Dart_Port port = data;
         ASSERT(port != 0);
         DartUtils::PostInt32(port, event_mask);
       }
     }
   }
-  if (interrupt_seen) {
-    // Handle after socket events, so we avoid closing a socket before we handle
-    // the current events.
-    HandleInterruptFd();
-  }
 }
 
 
 void EventHandlerImplementation::Poll(uword args) {
+  // Main event-handler thread loop.
   static const intptr_t kMaxEvents = 16;
   struct epoll_event events[kMaxEvents];
   EventHandler* handler = reinterpret_cast<EventHandler*>(args);
   EventHandlerImplementation* handler_impl = &handler->delegate_;
   ASSERT(handler_impl != NULL);
   while (!handler_impl->shutdown_) {
     intptr_t result = TEMP_FAILURE_RETRY(epoll_wait(handler_impl->epoll_fd_,
                                                     events,
                                                     kMaxEvents,
                                                     -1));
@@ skipping 13 matching lines @@
 void EventHandlerImplementation::Start(EventHandler* handler) {
   int result = dart::Thread::Start(&EventHandlerImplementation::Poll,
                                    reinterpret_cast<uword>(handler));
   if (result != 0) {
     FATAL1("Failed to start event handler thread %d", result);
   }
 }
 
 
 void EventHandlerImplementation::Shutdown() {
-  SendData(kShutdownId, 0, 0);
+  shutdown_ = true;
 }
 
 
-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);
+void EventHandlerImplementation::Notify(intptr_t id,
+                                        Dart_Port dart_port,
+                                        int64_t data) {
+  // This method is called by isolates, that is, not in the event-handler
+  // thread.
+  if (id == kTimerId) {
+    // Lock this region, as multiple isolates may attempt to update
+    // timeout_queue_.
+    // TODO(ajohnsen): Consider using a timer-fd per isolate to avoid the lock.
+    timer_mutex_.Lock();
+    timeout_queue_.UpdateTimeout(dart_port, data);
+    struct itimerspec it;
+    memset(&it, 0, sizeof(it));
+    if (timeout_queue_.HasTimeout()) {
+      int64_t millis = timeout_queue_.CurrentTimeout();
+      it.it_value.tv_sec = millis / 1000;
+      it.it_value.tv_nsec = (millis % 1000) * 1000000;
+    }
+    timerfd_settime(timer_fd_, TFD_TIMER_ABSTIME, &it, NULL);
+    timer_mutex_.Unlock();
+  } else {
+    if ((data & (1 << kShutdownReadCommand)) != 0) {
+      ASSERT(data == (1 << kShutdownReadCommand));
+      // Close the socket for reading.
+      shutdown(id, SHUT_RD);
+    } else if ((data & (1 << kShutdownWriteCommand)) != 0) {
+      ASSERT(data == (1 << kShutdownWriteCommand));
+      // Close the socket for writing.
+      shutdown(id, SHUT_WR);
+    } else if ((data & (1 << kCloseCommand)) != 0) {
+      ASSERT(data == (1 << kCloseCommand));
+      // Close the socket and free system resources and move on to
+      // next message.
+      // This will also remove the file descriptor from epoll.
+      Socket::Close(id);
+      DartUtils::PostInt32(dart_port, 1 << kDestroyedEvent);
+    } else {
+      // Add to epoll - this is the first time we see it.
+      AddToEpollInstance(epoll_fd_, id, dart_port, data);
+    }
+  }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)