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