Implement mac support for having multiple Dart_Port's registered on one OS socket

runtime/bin/eventhandler_macos.cc

Index: runtime/bin/eventhandler_macos.cc
diff --git a/runtime/bin/eventhandler_macos.cc b/runtime/bin/eventhandler_macos.cc
index 911cbada65b87ca8d8051f577ea61b846843f012..6caadc09622776e84c070dfddb4a2a5f7ef2e33d 100644
--- a/runtime/bin/eventhandler_macos.cc
+++ b/runtime/bin/eventhandler_macos.cc
@@ -6,6 +6,7 @@
 #if defined(TARGET_OS_MACOS)
 
 #include "bin/eventhandler.h"
+#include "bin/eventhandler_macos.h"
 
 #include <errno.h>  // NOLINT
 #include <pthread.h>  // NOLINT
@@ -17,7 +18,9 @@
 
 #include "bin/dartutils.h"
 #include "bin/fdutils.h"
+#include "bin/lockers.h"
 #include "bin/log.h"
+#include "bin/socket.h"
 #include "bin/thread.h"
 #include "bin/utils.h"
 #include "platform/hashmap.h"
@@ -27,60 +30,64 @@
 namespace dart {
 namespace bin {
 
-bool SocketData::HasReadEvent() {
-  return (mask_ & (1 << kInEvent)) != 0;
+
+bool DescriptorInfo::HasReadEvent() {
+  return (Mask() & (1 << kInEvent)) != 0;
 }
 
 
-bool SocketData::HasWriteEvent() {
-  return (mask_ & (1 << kOutEvent)) != 0;
+bool DescriptorInfo::HasWriteEvent() {
+  return (Mask() & (1 << kOutEvent)) != 0;
 }
 
 
 // Unregister the file descriptor for a SocketData structure with kqueue.
-static void RemoveFromKqueue(intptr_t kqueue_fd_, SocketData* sd) {
-  if (!sd->tracked_by_kqueue()) return;
+static void RemoveFromKqueue(intptr_t kqueue_fd_, DescriptorInfo* di) {
+  if (!di->tracked_by_kqueue()) return;
   static const intptr_t kMaxChanges = 2;
   struct kevent events[kMaxChanges];
-  EV_SET(events, sd->fd(), EVFILT_READ, EV_DELETE, 0, 0, NULL);
+  EV_SET(events, di->fd(), EVFILT_READ, EV_DELETE, 0, 0, NULL);
   VOID_NO_RETRY_EXPECTED(kevent(kqueue_fd_, events, 1, NULL, 0, NULL));
-  EV_SET(events, sd->fd(), EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
+  EV_SET(events, di->fd(), EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
   VOID_NO_RETRY_EXPECTED(kevent(kqueue_fd_, events, 1, NULL, 0, NULL));
-  sd->set_tracked_by_kqueue(false);
+  di->set_tracked_by_kqueue(false);
 }
 
 
 // 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 void AddToKqueue(intptr_t kqueue_fd_, DescriptorInfo* di) {
+  ASSERT(!di->tracked_by_kqueue());
   static const intptr_t kMaxChanges = 2;
   intptr_t changes = 0;
   struct kevent events[kMaxChanges];
   int flags = EV_ADD;
-  if (!sd->IsListeningSocket()) {
+  if (!di->IsListeningSocket()) {
     flags |= EV_CLEAR;
   }
+
+  ASSERT(di->HasReadEvent() || di->HasWriteEvent());
+
   // Register or unregister READ filter if needed.
-  if (sd->HasReadEvent()) {
+  if (di->HasReadEvent()) {
     EV_SET(events + changes,
-           sd->fd(),
+           di->fd(),
            EVFILT_READ,
            flags,
            0,
            0,
-           sd);
+           di);
     ++changes;
   }
   // Register or unregister WRITE filter if needed.
-  if (sd->HasWriteEvent()) {
+  if (di->HasWriteEvent()) {
     EV_SET(events + changes,
-           sd->fd(),
+           di->fd(),
            EVFILT_WRITE,
            flags,
            0,
            0,
-           sd);
+           di);
     ++changes;
   }
   ASSERT(changes > 0);
@@ -88,13 +95,15 @@ static void AddToKqueue(intptr_t kqueue_fd_, SocketData* sd) {
   int status =
       NO_RETRY_EXPECTED(kevent(kqueue_fd_, events, changes, NULL, 0, NULL));
   if (status == -1) {
+    // TODO(dart:io): Verify that the dart end is handling this correctly.
+
     // 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.
-    DartUtils::PostInt32(sd->port(), 1 << kCloseEvent);
+    di->NotifyAllDartPorts(1 << kCloseEvent);
   } else {
-    sd->set_tracked_by_kqueue(true);
+    di->set_tracked_by_kqueue(true);
   }
 }
 
@@ -136,21 +145,41 @@ EventHandlerImplementation::~EventHandlerImplementation() {
 }
 
 
-SocketData* EventHandlerImplementation::GetSocketData(intptr_t fd,
-                                                      bool is_listening) {
+void EventHandlerImplementation::UpdateKQueueInstance(intptr_t old_mask,
+                                                      DescriptorInfo *di) {
+  intptr_t new_mask = di->Mask();
+  if (old_mask != 0 && new_mask == 0) {
+    RemoveFromKqueue(kqueue_fd_, di);
+  } else if (old_mask == 0 && new_mask != 0) {
+    AddToKqueue(kqueue_fd_, di);
+  } else if (old_mask != 0 && new_mask != 0 && old_mask != new_mask) {
+    ASSERT(!di->IsListeningSocket());
+    RemoveFromKqueue(kqueue_fd_, di);
+    AddToKqueue(kqueue_fd_, di);
+  }
+}
+
+
+DescriptorInfo* EventHandlerImplementation::GetDescriptorInfo(
+    intptr_t fd, bool is_listening) {
   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) {
+  DescriptorInfo* di =
+      reinterpret_cast<DescriptorInfo*>(entry->value);
+  if (di == 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, is_listening);
-    entry->value = sd;
+    // new DescriptorInfo for the file descriptor is inserted.
+    if (is_listening) {
+      di = new DescriptorInfoMultiple(fd);
+    } else {
+      di = new DescriptorInfoSingle(fd);
+    }
+    entry->value = di;
   }
-  ASSERT(fd == sd->fd());
-  return sd;
+  ASSERT(fd == di->fd());
+  return di;
 }
 
 
@@ -188,38 +217,63 @@ void EventHandlerImplementation::HandleInterruptFd() {
     } else {
       ASSERT((msg[i].data & COMMAND_MASK) != 0);
 
-      SocketData* sd = GetSocketData(
+      DescriptorInfo* di = GetDescriptorInfo(
           msg[i].id, IS_LISTENING_SOCKET(msg[i].data));
       if (IS_COMMAND(msg[i].data, kShutdownReadCommand)) {
+        ASSERT(!di->IsListeningSocket());
         // Close the socket for reading.
-        shutdown(sd->fd(), SHUT_RD);
+        VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_RD));
       } else if (IS_COMMAND(msg[i].data, kShutdownWriteCommand)) {
+        ASSERT(!di->IsListeningSocket());
         // Close the socket for writing.
-        shutdown(sd->fd(), SHUT_WR);
+        VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_WR));
       } else if (IS_COMMAND(msg[i].data, kCloseCommand)) {
-        // Close the socket and free system resources.
-        RemoveFromKqueue(kqueue_fd_, sd);
-        intptr_t fd = sd->fd();
-        VOID_TEMP_FAILURE_RETRY(close(fd));
-        socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
-        delete sd;
-        DartUtils::PostInt32(msg[i].dart_port, 1 << kDestroyedEvent);
-      } else if (IS_COMMAND(msg[i].data, kReturnTokenCommand)) {
-        int count = TOKEN_COUNT(msg[i].data);
-        for (int i = 0; i < count; i++) {
-          if (sd->ReturnToken()) {
-            AddToKqueue(kqueue_fd_, sd);
+        // Close the socket and free system resources and move on to next
+        // message.
+        intptr_t old_mask = di->Mask();
+        Dart_Port port = msg[i].dart_port;
+        di->RemovePort(port);
+        intptr_t new_mask = di->Mask();
+        UpdateKQueueInstance(old_mask, di);
+
+        intptr_t fd = di->fd();
+        if (di->IsListeningSocket()) {
+          // We only close the socket file descriptor from the operating
+          // system if there are no other dart socket objects which
+          // are listening on the same (address, port) combination.
+
+          // TODO(dart:io): This assumes that all sockets listen before we
+          // close.
+          // This needs to be synchronized with a global datastructure.
+          if (new_mask == 0) {
+            socket_map_.Remove(
+                GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
+            di->Close();
+            delete di;
           }
+
+
+        } else {
+          ASSERT(new_mask == 0);
+          socket_map_.Remove(
+              GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
+          di->Close();
+          delete di;
         }
+
+        DartUtils::PostInt32(port, 1 << kDestroyedEvent);
+      } else if (IS_COMMAND(msg[i].data, kReturnTokenCommand)) {
+        intptr_t old_mask = di->Mask();
+        di->ReturnTokens(msg[i].dart_port, TOKEN_COUNT(msg[i].data));
+        UpdateKQueueInstance(old_mask, di);
       } else if (IS_COMMAND(msg[i].data, kSetEventMaskCommand)) {
         // `events` can only have kInEvent/kOutEvent flags set.
         intptr_t events = msg[i].data & EVENT_MASK;
         ASSERT(0 == (events & ~(1 << kInEvent | 1 << kOutEvent)));
 
-        // Setup events to wait for.
-        ASSERT(sd->port() == 0);
-        sd->SetPortAndMask(msg[i].dart_port, events);
-        AddToKqueue(kqueue_fd_, sd);
+        intptr_t old_mask = di->Mask();
+        di->SetPortAndMask(msg[i].dart_port, msg[i].data & EVENT_MASK);
+        UpdateKQueueInstance(old_mask, di);
       } else {
         UNREACHABLE();
       }
@@ -249,12 +303,12 @@ static void PrintEventMask(intptr_t fd, struct kevent* event) {
 
 
 intptr_t EventHandlerImplementation::GetEvents(struct kevent* event,
-                                               SocketData* sd) {
+                                               DescriptorInfo* di) {
 #ifdef DEBUG_KQUEUE
-  PrintEventMask(sd->fd(), event);
+  PrintEventMask(di->fd(), event);
 #endif
   intptr_t event_mask = 0;
-  if (sd->IsListeningSocket()) {
+  if (di->IsListeningSocket()) {
     // On a listening socket the READ event means that there are
     // connections ready to be accepted.
     if (event->filter == EVFILT_READ) {
@@ -310,15 +364,19 @@ void EventHandlerImplementation::HandleEvents(struct kevent* events,
     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);
+      DescriptorInfo* di =
+          reinterpret_cast<DescriptorInfo*>(events[i].udata);
+      intptr_t event_mask = GetEvents(events + i, di);
+      if ((event_mask & (1 << kErrorEvent)) != 0) {
+        di->NotifyAllDartPorts(event_mask);
+      }
+      event_mask &= ~(1 << kErrorEvent);
+
       if (event_mask != 0) {
-        if (sd->TakeToken()) {
-          // Took last token, remove from epoll.
-          RemoveFromKqueue(kqueue_fd_, sd);
-        }
-        Dart_Port port = sd->port();
+        intptr_t old_mask = di->Mask();
+        Dart_Port port = di->NextNotifyDartPort(event_mask);
         ASSERT(port != 0);
+        UpdateKQueueInstance(old_mask, di);
         DartUtils::PostInt32(port, event_mask);
       }
     }