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
26package sun.nio.fs;
27
28import java.lang.ref.Cleaner.Cleanable;
29import jdk.internal.misc.Unsafe;
30import jdk.internal.ref.CleanerFactory;
31
32/**
33 * A light-weight buffer in native memory.
34 */
35
36class NativeBuffer {
37    private static final Unsafe unsafe = Unsafe.getUnsafe();
38
39    private final long address;
40    private final int size;
41    private final Cleanable cleanable;
42
43    // optional "owner" to avoid copying
44    // (only safe for use by thread-local caches)
45    private Object owner;
46
47    private static class Deallocator implements Runnable {
48        private final long address;
49        Deallocator(long address) {
50            this.address = address;
51        }
52        public void run() {
53            unsafe.freeMemory(address);
54        }
55    }
56
57    NativeBuffer(int size) {
58        this.address = unsafe.allocateMemory(size);
59        this.size = size;
60        this.cleanable = CleanerFactory.cleaner()
61                                       .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    void free() {
77        cleanable.clean();
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}
90