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/*
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* Copyright (c) 2018, 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 java.io;
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import jdk.internal.misc.JavaIOFileDescriptorAccess;
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import jdk.internal.misc.SharedSecrets;
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import jdk.internal.ref.CleanerFactory;
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import jdk.internal.ref.PhantomCleanable;
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import java.lang.ref.Cleaner;
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/**
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* Cleanable for a FileDescriptor when it becomes phantom reachable.
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* For regular fds on Unix and regular handles on Windows
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* register a cleanup if fd != -1 or handle != -1.
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* <p>
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* Subclassed from {@code PhantomCleanable} so that {@code clear} can be
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* called to disable the cleanup when the handle is closed by any means other
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* than calling {@link FileDescriptor#close}.
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* Otherwise, it might incorrectly close the handle after it has been reused.
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*/
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final class FileCleanable extends PhantomCleanable<FileDescriptor> {
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// Access to FileDescriptor private fields;
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// avoids making fd and handle package private
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private static final JavaIOFileDescriptorAccess fdAccess =
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SharedSecrets.getJavaIOFileDescriptorAccess();
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/*
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* Raw close of the file fd and/or handle.
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* Used only for last chance cleanup.
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*/
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private static native void cleanupClose0(int fd, long handle) throws IOException;
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// The raw fd to close
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private final int fd;
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// The handle to close
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private final long handle;
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/**
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* Register a Cleanable with the FileDescriptor
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* if the FileDescriptor is non-null and valid.
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* @implNote
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* A exception (OutOfMemoryException) will leave the FileDescriptor
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* having allocated resources and leak the fd/handle.
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*
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* @param fdo the FileDescriptor; may be null
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*/
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static void register(FileDescriptor fdo) {
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if (fdo != null && fdo.valid()) {
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int fd = fdAccess.get(fdo);
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long handle = fdAccess.getHandle(fdo);
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fdo.registerCleanup(new FileCleanable(fdo, CleanerFactory.cleaner(), fd, handle));
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}
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}
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/**
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* Unregister a Cleanable from the FileDescriptor.
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* @param fdo the FileDescriptor; may be null
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*/
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static void unregister(FileDescriptor fdo) {
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if (fdo != null) {
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fdo.unregisterCleanup();
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}
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}
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/**
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* Constructor for a phantom cleanable reference.
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*
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* @param obj the object to monitor
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* @param cleaner the cleaner
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* @param fd file descriptor to close
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* @param handle handle to close
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*/
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private FileCleanable(FileDescriptor obj, Cleaner cleaner, int fd, long handle) {
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super(obj, cleaner);
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this.fd = fd;
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this.handle = handle;
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}
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/**
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* Close the native handle or fd.
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*/
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@Override
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protected void performCleanup() {
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try {
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cleanupClose0(fd, handle);
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} catch (IOException ioe) {
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throw new UncheckedIOException("close", ioe);
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}
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}
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}
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