/*

 * Copyright (c) 1998, 2012, 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.

 *

 * 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.

 */

/**

 *

 */

import java.io.*;

/**

 * Pipe output of one stream into input of another.

 */

public class StreamPipe extends Thread {

    private InputStream in;

    private OutputStream out;

    private String preamble;

    private JavaVM javaVM;

    private static Object lock = new Object();

    private static int count = 0;

    /* StreamPipe constructor : should only be called by plugTogether() method !!

     * If passed vm is not null :

     * -  This is StreamPipe usage when streams to pipe come from a given

     *    vm (JavaVM) process (the vm process must be started with a prefixed

     *    "-showversion" option to be able to determine as soon as possible when

     *    the vm process is started through the redirection of the streams).

     *    There must be a close connection between the StreamPipe instance and

     *    the JavaVM object on which a start() call has been done.

     *    run() method will flag distant JavaVM as started.

     * If passed vm is null :

     * -  We don't have control on the process which we want to redirect the passed

     *    streams.

     *    run() method will ignore distant process.

     */

    private StreamPipe(JavaVM vm, InputStream in, OutputStream out, String name) {

        super(name);

        this.in  = in;

        this.out = out;

        this.preamble = "# ";

        this.javaVM = vm;

    }

    // Install redirection of passed InputStream and OutputStream from passed JavaVM

    // to this vm standard output and input streams.

    public static void plugTogether(JavaVM vm, InputStream in, OutputStream out) {

        String name = null;

        synchronized (lock) {

            name = "TestLibrary: StreamPipe-" + (count ++ );

        }

        Thread pipe = new StreamPipe(vm, in, out, name);

        pipe.setDaemon(true);

        pipe.start();

    }

    /* Redirects the InputStream and OutputStream passed by caller to this

     * vm standard output and input streams.

     * (we just have to use fully parametered plugTogether() call with a null

     *  JavaVM input to do this).

     */

    public static void plugTogether(InputStream in, OutputStream out) {

        plugTogether(null, in, out);

    }

    // Starts redirection of streams.

    public void run() {

        BufferedReader r = new BufferedReader(new InputStreamReader(in), 1);

        BufferedWriter w = new BufferedWriter(new OutputStreamWriter(out));

        byte[] buf = new byte[256];

        try {

            String line;

            /* This is to check that the distant vm has started,

             * if such a vm has been provided at construction :

             * - As soon as we can read something from r BufferedReader,

             *   that means the distant vm is already started.

             * Thus we signal associated JavaVM object that it is now started.

             */

            if (((line = r.readLine()) != null) &&

                (javaVM != null)) {

                javaVM.setStarted();

            }

            // Redirects r on w.

            while (line != null) {

                w.write(preamble);

                w.write(line);

                w.newLine();

                w.flush();

                line = r.readLine();

            }

        } catch (InterruptedIOException iioe) {

            // Thread interrupted during IO operation. Terminate StreamPipe.

            return;

        } catch (IOException e) {

            System.err.println("*** IOException in StreamPipe.run:");

            e.printStackTrace();

        }

    }

}