/*

 * Copyright (c) 1995, 2021, 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.net;

import java.io.FileDescriptor;

import java.io.FileOutputStream;

import java.io.IOException;

import java.nio.channels.FileChannel;

/**

 * This stream extends FileOutputStream to implement a

 * SocketOutputStream. Note that this class should <b>NOT</b> be

 * public.

 *

 * @author      Jonathan Payne

 * @author      Arthur van Hoff

 */

class SocketOutputStream extends FileOutputStream {

    static {

        init();

    }

    private AbstractPlainSocketImpl impl = null;

    private byte temp[] = new byte[1];

    /**

     * Creates a new SocketOutputStream. Can only be called

     * by a Socket. This method needs to hang on to the owner Socket so

     * that the fd will not be closed.

     * @param impl the socket output stream implemented

     */

    SocketOutputStream(AbstractPlainSocketImpl impl) throws IOException {

        super(impl.getFileDescriptor());

        this.impl = impl;

    }

    /**

     * Returns the unique {@link java.nio.channels.FileChannel FileChannel}

     * object associated with this file output stream. </p>

     *

     * The {@code getChannel} method of {@code SocketOutputStream}

     * returns {@code null} since it is a socket based stream.</p>

     *

     * @return  the file channel associated with this file output stream

     *

     * @since 1.4

     */

    public final FileChannel getChannel() {

        return null;

    }

    /**

     * Writes to the socket.

     * @param fd the FileDescriptor

     * @param b the data to be written

     * @param off the start offset in the data

     * @param len the number of bytes that are written

     * @throws    IOException If an I/O error has occurred.

     */

    private native void socketWrite0(FileDescriptor fd, byte[] b, int off,

                                     int len) throws IOException;

    /**

     * Writes to the socket with appropriate locking of the

     * FileDescriptor.

     * @param b the data to be written

     * @param off the start offset in the data

     * @param len the number of bytes that are written

     * @throws    IOException If an I/O error has occurred.

     */

    private void socketWrite(byte b[], int off, int len) throws IOException {

        if (len <= 0 || off < 0 || len > b.length - off) {

            if (len == 0) {

                return;

            }

            throw new ArrayIndexOutOfBoundsException("len == " + len

                    + " off == " + off + " buffer length == " + b.length);

        }

        FileDescriptor fd = impl.acquireFD();

        try {

            socketWrite0(fd, b, off, len);

        } catch (SocketException se) {

            if (impl.isClosedOrPending()) {

                throw new SocketException("Socket closed");

            } else {

                throw se;

            }

        } finally {

            impl.releaseFD();

        }

    }

    /**

     * Writes a byte to the socket.

     * @param b the data to be written

     * @throws    IOException If an I/O error has occurred.

     */

    public void write(int b) throws IOException {

        temp[0] = (byte)b;

        socketWrite(temp, 0, 1);

    }

    /**

     * Writes the contents of the buffer <i>b</i> to the socket.

     * @param b the data to be written

     * @throws    SocketException If an I/O error has occurred.

     */

    public void write(byte b[]) throws IOException {

        socketWrite(b, 0, b.length);

    }

    /**

     * Writes <i>length</i> bytes from buffer <i>b</i> starting at

     * offset <i>len</i>.

     * @param b the data to be written

     * @param off the start offset in the data

     * @param len the number of bytes that are written

     * @throws    SocketException If an I/O error has occurred.

     */

    public void write(byte b[], int off, int len) throws IOException {

        socketWrite(b, off, len);

    }

    public void close() throws IOException {

        // No longer used. Socket.getOutputStream returns an

        // OutputStream which calls Socket.close directly

        assert false;

    }

    /**

     * Perform class load-time initializations.

     */

    private static native void init();

}