Extract common Mask/Dart_Port settings of linux event handler implementation to eventhandler.h

dart/runtime/bin/eventhandler_linux.cc

Index: dart/runtime/bin/eventhandler_linux.cc
diff --git a/dart/runtime/bin/eventhandler_linux.cc b/dart/runtime/bin/eventhandler_linux.cc
index 475b39dd378ab307aba9c356315cb9e328f13439..e758b9c11b842c30dd09a36ddd6caa12952eb102 100644
--- a/dart/runtime/bin/eventhandler_linux.cc
+++ b/dart/runtime/bin/eventhandler_linux.cc
@@ -6,6 +6,7 @@
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/eventhandler.h"
+#include "bin/eventhandler_linux.h"
 
 #include <errno.h>  // NOLINT
 #include <pthread.h>  // NOLINT
@@ -20,6 +21,7 @@
 #include "bin/dartutils.h"
 #include "bin/fdutils.h"
 #include "bin/log.h"
+#include "bin/lockers.h"
 #include "bin/socket.h"
 #include "bin/thread.h"
 #include "platform/utils.h"
@@ -29,46 +31,50 @@ namespace dart {
 namespace bin {
 
 
-intptr_t SocketData::GetPollEvents() {
+intptr_t DescriptorInfo::GetPollEvents() {
   // Do not ask for EPOLLERR and EPOLLHUP explicitly as they are
   // triggered anyway.
   intptr_t events = 0;
-  if ((mask_ & (1 << kInEvent)) != 0) {
+  if ((Mask() & (1 << kInEvent)) != 0) {
     events |= EPOLLIN;
   }
-  if ((mask_ & (1 << kOutEvent)) != 0) {
+  if ((Mask() & (1 << kOutEvent)) != 0) {
     events |= EPOLLOUT;
   }
   return events;
 }
 
 
-// Unregister the file descriptor for a SocketData structure with epoll.
-static void RemoveFromEpollInstance(intptr_t epoll_fd_, SocketData* sd) {
+// Unregister the file descriptor for a DescriptorInfo structure with
+// epoll.
+static void RemoveFromEpollInstance(intptr_t epoll_fd_,
+                                    DescriptorInfo* di) {
   VOID_NO_RETRY_EXPECTED(epoll_ctl(epoll_fd_,
                                    EPOLL_CTL_DEL,
-                                   sd->fd(),
+                                   di->fd(),
                                    NULL));
 }
 
 
-static void AddToEpollInstance(intptr_t epoll_fd_, SocketData* sd) {
+static void AddToEpollInstance(intptr_t epoll_fd_, DescriptorInfo* di) {
   struct epoll_event event;
-  event.events = EPOLLRDHUP | sd->GetPollEvents();
-  if (!sd->IsListeningSocket()) {
+  event.events = EPOLLRDHUP | di->GetPollEvents();
+  if (!di->IsListeningSocket()) {
     event.events |= EPOLLET;
   }
-  event.data.ptr = sd;
+  event.data.ptr = di;
   int status = NO_RETRY_EXPECTED(epoll_ctl(epoll_fd_,
                                            EPOLL_CTL_ADD,
-                                           sd->fd(),
+                                           di->fd(),
                                            &event));
   if (status == -1) {
+    // TODO(dart:io): Verify that the dart end is handling this correctly.
+
     // 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);
+    di->NotifyAllDartPorts(1 << kCloseEvent);
   }
 }
 
@@ -129,25 +135,44 @@ EventHandlerImplementation::~EventHandlerImplementation() {
 }
 
 
-SocketData* EventHandlerImplementation::GetSocketData(intptr_t fd,
-                                                      bool is_listening) {
+void EventHandlerImplementation::UpdateEpollInstance(intptr_t old_mask,
+                                                     DescriptorInfo *di) {
+  intptr_t new_mask = di->Mask();
+  if (old_mask != 0 && new_mask == 0) {
+    RemoveFromEpollInstance(epoll_fd_, di);
+  } else if (old_mask == 0 && new_mask != 0) {
+    AddToEpollInstance(epoll_fd_, di);
+  } else if (old_mask != 0 && new_mask != 0) {
+    if (di->IsListeningSocket()) {
+      ASSERT(old_mask == new_mask);
+    } else {

[Søren Gjesse, 2015/02/06 14:42:18]

Use UpdateEpollInstance here. Maybe also on Android.

[kustermann, 2015/02/09 08:50:22]

That would be an infinite recursive call, this function is UpdateEpollInstance!

We could add an optimization to selectively modify the epoll fd and try not to
remove+add it, but I think this is not a very common thing to go from
  kReadEvent -> kWriteEvent
  kWriteEvent -> kReadEvent
  kReadEvent|kWriteEvent -> kReadEvent
  kReadEvent|kWriteEvent -> kWriteEvent
  ...

[Søren Gjesse, 2015/02/09 09:09:21]

It probably isn't. We should still consider using EPOLL_CTL_MOD (I thought we
already had a method for that).

+      RemoveFromEpollInstance(epoll_fd_, di);
+      AddToEpollInstance(epoll_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.
+    // new DescriptorInfo for the file descriptor is inserted.
     if (is_listening) {
-      sd = new ListeningSocketData(fd);
+      di = new DescriptorInfoMultiple(fd);
     } else {
-      sd = new SocketData(fd);
+      di = new DescriptorInfoSingle(fd);
     }
-    entry->value = sd;
+    entry->value = di;
   }
-  ASSERT(fd == sd->fd());
-  return sd;
+  ASSERT(fd == di->fd());
+  return di;
 }
 
 
@@ -195,42 +220,61 @@ 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(!sd->IsListeningSocket());
+        ASSERT(!di->IsListeningSocket());
         // Close the socket for reading.
-        VOID_NO_RETRY_EXPECTED(shutdown(sd->fd(), SHUT_RD));
+        VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_RD));
       } else if (IS_COMMAND(msg[i].data, kShutdownWriteCommand)) {
-        ASSERT(!sd->IsListeningSocket());
+        ASSERT(!di->IsListeningSocket());
         // Close the socket for writing.
-        VOID_NO_RETRY_EXPECTED(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 and move on to next
         // message.
-        if (sd->RemovePort(msg[i].dart_port)) {
-          RemoveFromEpollInstance(epoll_fd_, sd);
-          intptr_t fd = sd->fd();
-          sd->Close();
-          socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
-          delete sd;
+        intptr_t old_mask = di->Mask();
+        Dart_Port port = msg[i].dart_port;
+        di->RemovePort(port);
+        intptr_t new_mask = di->Mask();
+        UpdateEpollInstance(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: 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(msg[i].dart_port, 1 << kDestroyedEvent);
+
+        DartUtils::PostInt32(port, 1 << kDestroyedEvent);
       } else if (IS_COMMAND(msg[i].data, kReturnTokenCommand)) {
         int count = TOKEN_COUNT(msg[i].data);
-        if (sd->ReturnToken(msg[i].dart_port, count)) {
-          AddToEpollInstance(epoll_fd_, sd);
-        }
+        intptr_t old_mask = di->Mask();
+        di->ReturnTokens(msg[i].dart_port, count);
+        UpdateEpollInstance(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.
-        if (sd->AddPort(msg[i].dart_port)) {
-          sd->SetMask(events);
-          AddToEpollInstance(epoll_fd_, sd);
-        }
+        intptr_t old_mask = di->Mask();
+        di->SetPortAndMask(msg[i].dart_port, msg[i].data & EVENT_MASK);
+        UpdateEpollInstance(old_mask, di);
       } else {
         UNREACHABLE();
       }
@@ -259,9 +303,9 @@ static void PrintEventMask(intptr_t fd, intptr_t events) {
 #endif
 
 intptr_t EventHandlerImplementation::GetPollEvents(intptr_t events,
-                                                   SocketData* sd) {
+                                                   DescriptorInfo* di) {
 #ifdef DEBUG_POLL
-  PrintEventMask(sd->fd(), events);
+  PrintEventMask(di->fd(), events);
 #endif
   if (events & EPOLLERR) {
     // Return error only if EPOLLIN is present.
@@ -290,15 +334,20 @@ void EventHandlerImplementation::HandleEvents(struct epoll_event* events,
         timeout_queue_.RemoveCurrent();
       }
     } else {
-      SocketData* sd = reinterpret_cast<SocketData*>(events[i].data.ptr);
-      intptr_t event_mask = GetPollEvents(events[i].events, sd);
+      DescriptorInfo* di =
+          reinterpret_cast<DescriptorInfo*>(events[i].data.ptr);
+      intptr_t event_mask = GetPollEvents(events[i].events, di);
+
+      if ((event_mask & (1 << kErrorEvent)) != 0) {
+        di->NotifyAllDartPorts(event_mask);
+      }
+      event_mask &= ~(1 << kErrorEvent);
+
       if (event_mask != 0) {
-        Dart_Port port = sd->port();
-        if (sd->TakeToken()) {
-          // Took last token, remove from epoll.
-          RemoveFromEpollInstance(epoll_fd_, sd);
-        }
+        intptr_t old_mask = di->Mask();
+        Dart_Port port = di->NextNotifyDartPort(event_mask);
         ASSERT(port != 0);
+        UpdateEpollInstance(old_mask, di);
         DartUtils::PostInt32(port, event_mask);
       }
     }