1 /*
   2  * Copyright (c) 2008, 2009, 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 
  26 package sun.nio.fs;
  27 
  28 import jdk.internal.misc.Unsafe;
  29 import jdk.internal.ref.CleanerFactory;
  30 
  31 import java.lang.ref.Cleaner;
  32 
  33 /**
  34  * A light-weight buffer in native memory.
  35  */
  36 
  37 class NativeBuffer {
  38     private static final Unsafe unsafe = Unsafe.getUnsafe();
  39 
  40     private final long address;
  41     private final int size;
  42     private final Cleaner.Cleanable cleanable;
  43 
  44     // optional "owner" to avoid copying
  45     // (only safe for use by thread-local caches)
  46     private Object owner;
  47 
  48     private static class Deallocator implements Runnable {
  49         private final long address;
  50         Deallocator(long address) {
  51             this.address = address;
  52         }
  53         public void run() {
  54             unsafe.freeMemory(address);
  55         }
  56     }
  57 
  58     NativeBuffer(int size) {
  59         this.address = unsafe.allocateMemory(size);
  60         this.size = size;
  61         this.cleanable = CleanerFactory.cleaner().register(this, new Deallocator(address));
  62     }
  63 
  64     void release() {
  65         NativeBuffers.releaseNativeBuffer(this);
  66     }
  67 
  68     long address() {
  69         return address;
  70     }
  71 
  72     int size() {
  73         return size;
  74     }
  75 
  76     Cleaner.Cleanable cleanable() {
  77         return cleanable;
  78     }
  79 
  80     // not synchronized; only safe for use by thread-local caches
  81     void setOwner(Object owner) {
  82         this.owner = owner;
  83     }
  84 
  85     // not synchronized; only safe for use by thread-local caches
  86     Object owner() {
  87         return owner;
  88     }
  89 }