545 lines
13 KiB
Java
545 lines
13 KiB
Java
/* FileChannelImpl.java --
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Copyright (C) 2002, 2004, 2005, 2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.java.nio.channels;
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import gnu.classpath.Configuration;
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import gnu.java.nio.FileLockImpl;
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.nio.MappedByteBuffer;
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import java.nio.channels.ClosedChannelException;
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import java.nio.channels.FileChannel;
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import java.nio.channels.FileLock;
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import java.nio.channels.NonReadableChannelException;
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import java.nio.channels.NonWritableChannelException;
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import java.nio.channels.ReadableByteChannel;
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import java.nio.channels.WritableByteChannel;
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/**
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* This file is not user visible !
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* But alas, Java does not have a concept of friendly packages
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* so this class is public.
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* Instances of this class are created by invoking getChannel
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* Upon a Input/Output/RandomAccessFile object.
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*/
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public final class FileChannelImpl extends FileChannel
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{
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// These are mode values for open().
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public static final int READ = 1;
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public static final int WRITE = 2;
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public static final int APPEND = 4;
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// EXCL is used only when making a temp file.
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public static final int EXCL = 8;
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public static final int SYNC = 16;
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public static final int DSYNC = 32;
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private static native void init();
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static
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{
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if (Configuration.INIT_LOAD_LIBRARY)
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{
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System.loadLibrary("javanio");
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}
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init();
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}
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/**
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* This is the actual native file descriptor value
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*/
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// System's notion of file descriptor. It might seem redundant to
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// initialize this given that it is reassigned in the constructors.
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// However, this is necessary because if open() throws an exception
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// we want to make sure this has the value -1. This is the most
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// efficient way to accomplish that.
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private int fd = -1;
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private long pos;
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private int mode;
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public FileChannelImpl ()
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{
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}
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/* Open a file. MODE is a combination of the above mode flags. */
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/* This is a static factory method, so that VM implementors can decide
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* substitute subclasses of FileChannelImpl. */
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public static FileChannelImpl create(File file, int mode)
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throws FileNotFoundException
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{
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return new FileChannelImpl(file, mode);
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}
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/* Open a file. MODE is a combination of the above mode flags. */
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private FileChannelImpl (File file, int mode) throws FileNotFoundException
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{
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final String path = file.getPath();
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fd = open (path, mode);
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this.mode = mode;
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// First open the file and then check if it is a a directory
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// to avoid race condition.
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if (file.isDirectory())
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{
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try
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{
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close();
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}
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catch (IOException e)
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{
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/* ignore it */
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}
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throw new FileNotFoundException(path + " is a directory");
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}
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}
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/* Used by init() (native code) */
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FileChannelImpl (int fd, int mode)
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{
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this.fd = fd;
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this.mode = mode;
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}
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public static FileChannelImpl in;
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public static FileChannelImpl out;
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public static FileChannelImpl err;
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private native int open (String path, int mode) throws FileNotFoundException;
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public native int available () throws IOException;
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private native long implPosition () throws IOException;
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private native void seek (long newPosition) throws IOException;
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private native void implTruncate (long size) throws IOException;
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public native void unlock (long pos, long len) throws IOException;
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public native long size () throws IOException;
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protected native void implCloseChannel() throws IOException;
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/**
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* Makes sure the Channel is properly closed.
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*/
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protected void finalize() throws IOException
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{
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this.close();
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}
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public int read (ByteBuffer dst) throws IOException
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{
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int result;
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byte[] buffer = new byte [dst.remaining ()];
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result = read (buffer, 0, buffer.length);
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if (result > 0)
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dst.put (buffer, 0, result);
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return result;
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}
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public int read (ByteBuffer dst, long position)
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throws IOException
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{
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if (position < 0)
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throw new IllegalArgumentException ();
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long oldPosition = implPosition ();
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position (position);
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int result = read(dst);
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position (oldPosition);
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return result;
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}
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public native int read ()
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throws IOException;
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public native int read (byte[] buffer, int offset, int length)
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throws IOException;
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public long read (ByteBuffer[] dsts, int offset, int length)
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throws IOException
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{
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long result = 0;
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for (int i = offset; i < offset + length; i++)
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{
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result += read (dsts [i]);
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}
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return result;
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}
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public int write (ByteBuffer src) throws IOException
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{
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int len = src.remaining ();
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if (src.hasArray())
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{
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byte[] buffer = src.array();
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write(buffer, src.arrayOffset() + src.position(), len);
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src.position(src.position() + len);
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}
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else
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{
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// Use a more efficient native method! FIXME!
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byte[] buffer = new byte [len];
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src.get (buffer, 0, len);
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write (buffer, 0, len);
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}
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return len;
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}
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public int write (ByteBuffer src, long position)
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throws IOException
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{
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if (position < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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if ((mode & WRITE) == 0)
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throw new NonWritableChannelException ();
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int result;
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long oldPosition;
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oldPosition = implPosition ();
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seek (position);
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result = write(src);
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seek (oldPosition);
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return result;
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}
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public native void write (byte[] buffer, int offset, int length)
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throws IOException;
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public native void write (int b) throws IOException;
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public long write(ByteBuffer[] srcs, int offset, int length)
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throws IOException
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{
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long result = 0;
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for (int i = offset;i < offset + length;i++)
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{
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result += write (srcs[i]);
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}
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return result;
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}
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public native MappedByteBuffer mapImpl (char mode, long position, int size)
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throws IOException;
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public MappedByteBuffer map (FileChannel.MapMode mode,
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long position, long size)
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throws IOException
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{
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char nmode = 0;
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if (mode == MapMode.READ_ONLY)
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{
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nmode = 'r';
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if ((this.mode & READ) == 0)
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throw new NonReadableChannelException();
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}
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else if (mode == MapMode.READ_WRITE || mode == MapMode.PRIVATE)
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{
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nmode = mode == MapMode.READ_WRITE ? '+' : 'c';
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if ((this.mode & (READ|WRITE)) != (READ|WRITE))
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throw new NonWritableChannelException();
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}
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else
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throw new IllegalArgumentException ();
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if (position < 0 || size < 0 || size > Integer.MAX_VALUE)
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throw new IllegalArgumentException ();
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return mapImpl(nmode, position, (int) size);
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}
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/**
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* msync with the disk
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*/
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public void force (boolean metaData) throws IOException
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{
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if (!isOpen ())
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throw new ClosedChannelException ();
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}
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// like transferTo, but with a count of less than 2Gbytes
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private int smallTransferTo (long position, int count,
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WritableByteChannel target)
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throws IOException
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{
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ByteBuffer buffer;
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try
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{
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// Try to use a mapped buffer if we can. If this fails for
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// any reason we'll fall back to using a ByteBuffer.
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buffer = map (MapMode.READ_ONLY, position, count);
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}
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catch (IOException e)
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{
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buffer = ByteBuffer.allocate (count);
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read (buffer, position);
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buffer.flip();
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}
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return target.write (buffer);
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}
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public long transferTo (long position, long count,
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WritableByteChannel target)
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throws IOException
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{
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if (position < 0
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|| count < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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if ((mode & READ) == 0)
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throw new NonReadableChannelException ();
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final int pageSize = 65536;
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long total = 0;
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while (count > 0)
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{
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int transferred
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= smallTransferTo (position, (int)Math.min (count, pageSize),
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target);
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if (transferred < 0)
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break;
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total += transferred;
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position += transferred;
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count -= transferred;
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}
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return total;
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}
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// like transferFrom, but with a count of less than 2Gbytes
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private int smallTransferFrom (ReadableByteChannel src, long position,
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int count)
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throws IOException
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{
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ByteBuffer buffer = null;
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if (src instanceof FileChannel)
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{
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try
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{
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// Try to use a mapped buffer if we can. If this fails
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// for any reason we'll fall back to using a ByteBuffer.
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buffer = ((FileChannel)src).map (MapMode.READ_ONLY, position,
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count);
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}
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catch (IOException e)
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{
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}
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}
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if (buffer == null)
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{
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buffer = ByteBuffer.allocate ((int) count);
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src.read (buffer);
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buffer.flip();
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}
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return write (buffer, position);
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}
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public long transferFrom (ReadableByteChannel src, long position,
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long count)
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throws IOException
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{
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if (position < 0
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|| count < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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if ((mode & WRITE) == 0)
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throw new NonWritableChannelException ();
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final int pageSize = 65536;
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long total = 0;
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while (count > 0)
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{
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int transferred = smallTransferFrom (src, position,
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(int)Math.min (count, pageSize));
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if (transferred < 0)
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break;
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total += transferred;
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position += transferred;
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count -= transferred;
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}
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return total;
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}
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public FileLock tryLock (long position, long size, boolean shared)
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throws IOException
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{
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if (position < 0
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|| size < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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if (shared && (mode & READ) == 0)
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throw new NonReadableChannelException ();
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if (!shared && (mode & WRITE) == 0)
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throw new NonWritableChannelException ();
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boolean completed = false;
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try
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{
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begin();
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boolean lockable = lock(position, size, shared, false);
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completed = true;
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return (lockable
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? new FileLockImpl(this, position, size, shared)
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: null);
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}
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finally
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{
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end(completed);
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}
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}
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/** Try to acquire a lock at the given position and size.
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* On success return true.
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* If wait as specified, block until we can get it.
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* Otherwise return false.
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*/
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private native boolean lock(long position, long size,
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boolean shared, boolean wait) throws IOException;
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public FileLock lock (long position, long size, boolean shared)
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throws IOException
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{
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if (position < 0
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|| size < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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boolean completed = false;
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try
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{
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boolean lockable = lock(position, size, shared, true);
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completed = true;
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return (lockable
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? new FileLockImpl(this, position, size, shared)
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: null);
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}
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finally
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{
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end(completed);
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}
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}
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public long position ()
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throws IOException
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{
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if (!isOpen ())
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throw new ClosedChannelException ();
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return implPosition ();
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}
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public FileChannel position (long newPosition)
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throws IOException
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{
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if (newPosition < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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// FIXME note semantics if seeking beyond eof.
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// We should seek lazily - only on a write.
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seek (newPosition);
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return this;
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}
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public FileChannel truncate (long size)
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throws IOException
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{
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if (size < 0)
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throw new IllegalArgumentException ();
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if (!isOpen ())
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throw new ClosedChannelException ();
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if ((mode & WRITE) == 0)
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throw new NonWritableChannelException ();
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if (size < size ())
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implTruncate (size);
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return this;
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}
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/**
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* @return The native file descriptor.
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*/
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public int getNativeFD()
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{
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return fd;
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}
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}
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