Several bugfixes in dart:io's handing of sockets

dart/runtime/bin/eventhandler_linux.h

 // 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.
 
 #ifndef BIN_EVENTHANDLER_LINUX_H_
 #define BIN_EVENTHANDLER_LINUX_H_
 
 #if !defined(BIN_EVENTHANDLER_H_)
 #error Do not include eventhandler_linux.h directly; use eventhandler.h instead.
 #endif
@@ skipping 169 matching lines @@
   bool AddPort(Dart_Port port) {
     HashMap::Entry* entry = tokens_map_.Lookup(
         GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port), true);
     entry->value = reinterpret_cast<void*>(kTokenCount);
     return live_ports_.Add(port);
   }
 
   virtual bool RemovePort(Dart_Port port) {
     HashMap::Entry* entry = tokens_map_.Lookup(
         GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port), false);
-    ASSERT(entry != NULL);
-    intptr_t tokens = reinterpret_cast<intptr_t>(entry->value);
-    if (tokens == 0) {
-      while (idle_ports_.head() != port) {
-        idle_ports_.Rotate();
+    if (entry != NULL) {
+      intptr_t tokens = reinterpret_cast<intptr_t>(entry->value);
+      if (tokens == 0) {
+        while (idle_ports_.head() != port) {
+          idle_ports_.Rotate();
+        }
+        idle_ports_.RemoveHead();
+      } else {
+        while (live_ports_.head() != port) {
+          live_ports_.Rotate();
+        }
+        live_ports_.RemoveHead();
       }
-      idle_ports_.RemoveHead();
+      tokens_map_.Remove(
+          GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port));
     } else {
-      while (live_ports_.head() != port) {
-        live_ports_.Rotate();
-      }
-      live_ports_.RemoveHead();
+      // NOTE: This is a listening socket which has been immediately closed.
+      //
+      // If a listening socket is not listened on, the event handler does not
+      // know about it beforehand. So the first time the event handler knows
+      // about it, is when it is supposed to be closed. We therefore do nothing
+      // here.
+      //
+      // But whether to close it, depends on whether other isolates have it open
+      // as well or not.
     }
-    tokens_map_.Remove(
-        GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port));
     return !live_ports_.HasHead();
   }
 
   bool TakeToken() {
     ASSERT(live_ports_.HasHead());
     Dart_Port port = live_ports_.head();
     HashMap::Entry* entry = tokens_map_.Lookup(
         GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port), false);
     ASSERT(entry != NULL);
     intptr_t tokens = reinterpret_cast<intptr_t>(entry->value);
@@ skipping 67 matching lines @@
   bool shutdown_;
   int interrupt_fds_[2];
   int epoll_fd_;
   int timer_fd_;
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_EVENTHANDLER_LINUX_H_