rev 51958 : 8211122: Reduce the number of internal classes made accessible to jdk.unsupported
Reviewed-by: alanb, dfuchs, kvn

   1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package java.net;
  26 
  27 import jdk.internal.access.JavaIOFileDescriptorAccess;
  28 import jdk.internal.access.SharedSecrets;
  29 import jdk.internal.ref.CleanerFactory;
  30 import jdk.internal.ref.PhantomCleanable;
  31 
  32 import java.io.FileDescriptor;
  33 import java.io.IOException;
  34 import java.io.UncheckedIOException;
  35 import java.lang.ref.Cleaner;
  36 
  37 
  38 /**
  39  * Cleanable for a socket/datagramsocket FileDescriptor when it becomes phantom reachable.
  40  * Create a cleanup if the raw fd != -1. Windows closes sockets using the fd.
  41  * Subclassed from {@code PhantomCleanable} so that {@code clear} can be
  42  * called to disable the cleanup when the socket fd is closed by any means
  43  * other than calling {@link FileDescriptor#close}.
  44  * Otherwise, it might incorrectly close the handle or fd after it has been reused.
  45  */
  46 final class SocketCleanable extends PhantomCleanable<FileDescriptor> {
  47 
  48     // Access to FileDescriptor private fields
  49     private static final JavaIOFileDescriptorAccess fdAccess =
  50             SharedSecrets.getJavaIOFileDescriptorAccess();
  51 
  52     // Native function to call NET_SocketClose(fd)
  53     // Used only for last chance cleanup.
  54     private static native void cleanupClose0(int fd) throws IOException;
  55 
  56     // The raw fd to close
  57     private final int fd;
  58 
  59     /**
  60      * Register a socket specific Cleanable with the FileDescriptor
  61      * if the FileDescriptor is non-null and the raw fd is != -1.
  62      *
  63      * @param fdo the FileDescriptor; may be null
  64      */
  65     static void register(FileDescriptor fdo) {
  66         if (fdo != null && fdo.valid()) {
  67             int fd = fdAccess.get(fdo);
  68             fdAccess.registerCleanup(fdo,
  69                     new SocketCleanable(fdo, CleanerFactory.cleaner(), fd));
  70         }
  71     }
  72 
  73     /**
  74      * Unregister a Cleanable from the FileDescriptor.
  75      * @param fdo the FileDescriptor; may be null
  76      */
  77     static void unregister(FileDescriptor fdo) {
  78         if (fdo != null) {
  79             fdAccess.unregisterCleanup(fdo);
  80         }
  81     }
  82 
  83     /**
  84      * Constructor for a phantom cleanable reference.
  85      *
  86      * @param obj     the object to monitor
  87      * @param cleaner the cleaner
  88      * @param fd      file descriptor to close
  89      */
  90     private SocketCleanable(FileDescriptor obj, Cleaner cleaner, int fd) {
  91         super(obj, cleaner);
  92         this.fd = fd;
  93     }
  94 
  95     /**
  96      * Close the native handle or fd.
  97      */
  98     @Override
  99     protected void performCleanup() {
 100         try {
 101             cleanupClose0(fd);
 102         } catch (IOException ioe) {
 103             throw new UncheckedIOException("close", ioe);
 104         }
 105     }
 106 }
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