94 lines
3.0 KiB
Java
94 lines
3.0 KiB
Java
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/*
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* Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.nio.fs;
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import sun.misc.Unsafe;
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import sun.misc.Cleaner;
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/**
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* A light-weight buffer in native memory.
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*/
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class NativeBuffer {
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private static final Unsafe unsafe = Unsafe.getUnsafe();
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private final long address;
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private final int size;
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private final Cleaner cleaner;
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// optional "owner" to avoid copying
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// (only safe for use by thread-local caches)
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private Object owner;
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private static class Deallocator implements Runnable {
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private final long address;
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Deallocator(long address) {
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this.address = address;
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}
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public void run() {
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unsafe.freeMemory(address);
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}
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}
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NativeBuffer(int size) {
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this.address = unsafe.allocateMemory(size);
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this.size = size;
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this.cleaner = Cleaner.create(this, new Deallocator(address));
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}
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// Android-note: releaseNativeBuffer() ensures that its argument is strongly reachable.
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void release() {
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NativeBuffers.releaseNativeBuffer(this);
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}
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// BEGIN Android-note: Lifecycle contract of NativeBuffer.address() relative to release().
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// We require that:
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// 1) NativeBuffer is ALWAYS explicitly release()ed before being dropped, and
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// 2) The result of address() is only used before release() is called.
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// END Android-note: Lifecycle contract of NativeBuffer.address() relative to release().
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long address() {
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return address;
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}
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int size() {
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return size;
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}
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Cleaner cleaner() {
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return cleaner;
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}
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// not synchronized; only safe for use by thread-local caches
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void setOwner(Object owner) {
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this.owner = owner;
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}
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// not synchronized; only safe for use by thread-local caches
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Object owner() {
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return owner;
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}
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}
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