/*

 * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.nio.fs;

import java.lang.ref.Cleaner.Cleanable;

import jdk.internal.misc.Unsafe;

import jdk.internal.ref.CleanerFactory;

/**

 * A light-weight buffer in native memory.

 */

class NativeBuffer {

    private static final Unsafe unsafe = Unsafe.getUnsafe();

    private final long address;

    private final int size;

    private final Cleanable cleanable;

    // optional "owner" to avoid copying

    // (only safe for use by thread-local caches)

    private Object owner;

    private static class Deallocator implements Runnable {

        private final long address;

        Deallocator(long address) {

            this.address = address;

        }

        public void run() {

            unsafe.freeMemory(address);

        }

    }

    NativeBuffer(int size) {

        this.address = unsafe.allocateMemory(size);

        this.size = size;

        this.cleanable = CleanerFactory.cleaner()

                                       .register(this, new Deallocator(address));

    }

    void release() {

        NativeBuffers.releaseNativeBuffer(this);

    }

    long address() {

        return address;

    }

    int size() {

        return size;

    }

    void free() {

        cleanable.clean();

    }

    // not synchronized; only safe for use by thread-local caches

    void setOwner(Object owner) {

        this.owner = owner;

    }

    // not synchronized; only safe for use by thread-local caches

    Object owner() {

        return owner;

    }

}