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/*
* 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 sun.misc.Unsafe;
import sun.misc.Cleaner;
/**
* 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 Cleaner cleaner;
// 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.cleaner = Cleaner.create(this, new Deallocator(address));
}
// Android-note: releaseNativeBuffer() ensures that its argument is strongly reachable.
void release() {
NativeBuffers.releaseNativeBuffer(this);
}
// BEGIN Android-note: Lifecycle contract of NativeBuffer.address() relative to release().
// We require that:
// 1) NativeBuffer is ALWAYS explicitly release()ed before being dropped, and
// 2) The result of address() is only used before release() is called.
// END Android-note: Lifecycle contract of NativeBuffer.address() relative to release().
long address() {
return address;
}
int size() {
return size;
}
Cleaner cleaner() {
return cleaner;
}
// 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;
}
}
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