--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/io/FileDescriptor.java Fri Feb 23 14:26:29 2018 -0500
@@ -0,0 +1,369 @@
+/*
+ * Copyright (c) 2003, 2018, 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 java.io;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import jdk.internal.misc.JavaIOFileDescriptorAccess;
+import jdk.internal.misc.SharedSecrets;
+import jdk.internal.ref.PhantomCleanable;
+
+/**
+ * Instances of the file descriptor class serve as an opaque handle
+ * to the underlying machine-specific structure representing an open
+ * file, an open socket, or another source or sink of bytes.
+ * The main practical use for a file descriptor is to create a
+ * {@link FileInputStream} or {@link FileOutputStream} to contain it.
+ * <p>
+ * Applications should not create their own file descriptors.
+ *
+ * @author Pavani Diwanji
+ * @since 1.0
+ */
+public final class FileDescriptor {
+
+ private int fd;
+
+ private long handle;
+
+ private Closeable parent;
+ private List<Closeable> otherParents;
+ private boolean closed;
+
+ /**
+ * true, if file is opened for appending.
+ */
+ private boolean append;
+
+ static {
+ initIDs();
+ }
+
+ // Set up JavaIOFileDescriptorAccess in SharedSecrets
+ static {
+ SharedSecrets.setJavaIOFileDescriptorAccess(
+ new JavaIOFileDescriptorAccess() {
+ public void set(FileDescriptor fdo, int fd) {
+ fdo.set(fd);
+ }
+
+ public int get(FileDescriptor fdo) {
+ return fdo.fd;
+ }
+
+ public void setAppend(FileDescriptor fdo, boolean append) {
+ fdo.append = append;
+ }
+
+ public boolean getAppend(FileDescriptor fdo) {
+ return fdo.append;
+ }
+
+ public void close(FileDescriptor fdo) throws IOException {
+ fdo.close();
+ }
+
+ /* Register for a normal FileCleanable fd/handle cleanup. */
+ public void registerCleanup(FileDescriptor fdo) {
+ FileCleanable.register(fdo);
+ }
+
+ /* Register a custom PhantomCleanup. */
+ public void registerCleanup(FileDescriptor fdo,
+ PhantomCleanable<FileDescriptor> cleanup) {
+ fdo.registerCleanup(cleanup);
+ }
+
+ public void unregisterCleanup(FileDescriptor fdo) {
+ fdo.unregisterCleanup();
+ }
+
+ public void setHandle(FileDescriptor fdo, long handle) {
+ fdo.setHandle(handle);
+ }
+
+ public long getHandle(FileDescriptor fdo) {
+ return fdo.handle;
+ }
+ }
+ );
+ }
+
+ /**
+ * Cleanup in case FileDescriptor is not explicitly closed.
+ */
+ private PhantomCleanable<FileDescriptor> cleanup;
+
+ /**
+ * Constructs an (invalid) FileDescriptor object.
+ * The fd or handle is set later.
+ */
+ public FileDescriptor() {
+ fd = -1;
+ handle = -1;
+ }
+
+ /**
+ * Used for standard input, output, and error only.
+ * For Windows the corresponding handle is initialized.
+ * For Unix the append mode is cached.
+ * @param fd the raw fd number (0, 1, 2)
+ */
+ private FileDescriptor(int fd) {
+ this.fd = fd;
+ this.handle = getHandle(fd);
+ this.append = getAppend(fd);
+ }
+
+ /**
+ * A handle to the standard input stream. Usually, this file
+ * descriptor is not used directly, but rather via the input stream
+ * known as {@code System.in}.
+ *
+ * @see java.lang.System#in
+ */
+ public static final FileDescriptor in = new FileDescriptor(0);
+
+ /**
+ * A handle to the standard output stream. Usually, this file
+ * descriptor is not used directly, but rather via the output stream
+ * known as {@code System.out}.
+ * @see java.lang.System#out
+ */
+ public static final FileDescriptor out = new FileDescriptor(1);
+
+ /**
+ * A handle to the standard error stream. Usually, this file
+ * descriptor is not used directly, but rather via the output stream
+ * known as {@code System.err}.
+ *
+ * @see java.lang.System#err
+ */
+ public static final FileDescriptor err = new FileDescriptor(2);
+
+ /**
+ * Tests if this file descriptor object is valid.
+ *
+ * @return {@code true} if the file descriptor object represents a
+ * valid, open file, socket, or other active I/O connection;
+ * {@code false} otherwise.
+ */
+ public boolean valid() {
+ return (handle != -1) || (fd != -1);
+ }
+
+ /**
+ * Force all system buffers to synchronize with the underlying
+ * device. This method returns after all modified data and
+ * attributes of this FileDescriptor have been written to the
+ * relevant device(s). In particular, if this FileDescriptor
+ * refers to a physical storage medium, such as a file in a file
+ * system, sync will not return until all in-memory modified copies
+ * of buffers associated with this FileDescriptor have been
+ * written to the physical medium.
+ *
+ * sync is meant to be used by code that requires physical
+ * storage (such as a file) to be in a known state For
+ * example, a class that provided a simple transaction facility
+ * might use sync to ensure that all changes to a file caused
+ * by a given transaction were recorded on a storage medium.
+ *
+ * sync only affects buffers downstream of this FileDescriptor. If
+ * any in-memory buffering is being done by the application (for
+ * example, by a BufferedOutputStream object), those buffers must
+ * be flushed into the FileDescriptor (for example, by invoking
+ * OutputStream.flush) before that data will be affected by sync.
+ *
+ * @exception SyncFailedException
+ * Thrown when the buffers cannot be flushed,
+ * or because the system cannot guarantee that all the
+ * buffers have been synchronized with physical media.
+ * @since 1.1
+ */
+ public native void sync() throws SyncFailedException;
+
+ /* This routine initializes JNI field offsets for the class */
+ private static native void initIDs();
+
+ /*
+ * On Windows return the handle for the standard streams.
+ */
+ private static native long getHandle(int d);
+
+ /**
+ * Returns true, if the file was opened for appending.
+ */
+ private static native boolean getAppend(int fd);
+
+ /**
+ * Set the fd.
+ * Used on Unix and for sockets on Windows and Unix.
+ * If setting to -1, clear the cleaner.
+ * The {@link #registerCleanup} method should be called for new fds.
+ * @param fd the raw fd or -1 to indicate closed
+ */
+ @SuppressWarnings("unchecked")
+ synchronized void set(int fd) {
+ if (fd == -1 && cleanup != null) {
+ cleanup.clear();
+ cleanup = null;
+ }
+ this.fd = fd;
+ }
+
+ /**
+ * Set the handle.
+ * Used on Windows for regular files.
+ * If setting to -1, clear the cleaner.
+ * The {@link #registerCleanup} method should be called for new handles.
+ * @param handle the handle or -1 to indicate closed
+ */
+ @SuppressWarnings("unchecked")
+ void setHandle(long handle) {
+ if (handle == -1 && cleanup != null) {
+ cleanup.clear();
+ cleanup = null;
+ }
+ this.handle = handle;
+ }
+
+ /**
+ * Register a cleanup for the current handle.
+ * Used directly in java.io and indirectly via fdAccess.
+ * The cleanup should be registered after the handle is set in the FileDescriptor.
+ * @param cleanable a PhantomCleanable to register
+ */
+ @SuppressWarnings("unchecked")
+ synchronized void registerCleanup(PhantomCleanable<FileDescriptor> cleanable) {
+ Objects.requireNonNull(cleanable, "cleanable");
+ if (cleanup != null) {
+ cleanup.clear();
+ }
+ cleanup = cleanable;
+ }
+
+ /**
+ * Unregister a cleanup for the current raw fd or handle.
+ * Used directly in java.io and indirectly via fdAccess.
+ * Normally {@link #close()} should be used except in cases where
+ * it is certain the caller will close the raw fd and the cleanup
+ * must not close the raw fd. {@link #unregisterCleanup()} must be
+ * called before the raw fd is closed to prevent a race that makes
+ * it possible for the fd to be reallocated to another use and later
+ * the cleanup might be invoked.
+ */
+ synchronized void unregisterCleanup() {
+ if (cleanup != null) {
+ cleanup.clear();
+ }
+ cleanup = null;
+ }
+
+ /**
+ * Close the raw file descriptor or handle, if it has not already been closed.
+ * The native code sets the fd and handle to -1.
+ * Clear the cleaner so the close does not happen twice.
+ * Package private to allow it to be used in java.io.
+ * @throws IOException if close fails
+ */
+ @SuppressWarnings("unchecked")
+ synchronized void close() throws IOException {
+ unregisterCleanup();
+ close0();
+ }
+
+ /*
+ * Close the raw file descriptor or handle, if it has not already been closed
+ * and set the fd and handle to -1.
+ */
+ private native void close0() throws IOException;
+
+ /*
+ * Package private methods to track referents.
+ * If multiple streams point to the same FileDescriptor, we cycle
+ * through the list of all referents and call close()
+ */
+
+ /**
+ * Attach a Closeable to this FD for tracking.
+ * parent reference is added to otherParents when
+ * needed to make closeAll simpler.
+ */
+ synchronized void attach(Closeable c) {
+ if (parent == null) {
+ // first caller gets to do this
+ parent = c;
+ } else if (otherParents == null) {
+ otherParents = new ArrayList<>();
+ otherParents.add(parent);
+ otherParents.add(c);
+ } else {
+ otherParents.add(c);
+ }
+ }
+
+ /**
+ * Cycle through all Closeables sharing this FD and call
+ * close() on each one.
+ *
+ * The caller closeable gets to call close0().
+ */
+ @SuppressWarnings("try")
+ synchronized void closeAll(Closeable releaser) throws IOException {
+ if (!closed) {
+ closed = true;
+ IOException ioe = null;
+ try (releaser) {
+ if (otherParents != null) {
+ for (Closeable referent : otherParents) {
+ try {
+ referent.close();
+ } catch(IOException x) {
+ if (ioe == null) {
+ ioe = x;
+ } else {
+ ioe.addSuppressed(x);
+ }
+ }
+ }
+ }
+ } catch(IOException ex) {
+ /*
+ * If releaser close() throws IOException
+ * add other exceptions as suppressed.
+ */
+ if (ioe != null)
+ ex.addSuppressed(ioe);
+ ioe = ex;
+ } finally {
+ if (ioe != null)
+ throw ioe;
+ }
+ }
+ }
+}