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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 *

 * 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.

 *

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 */

/* @test

 * @bug 6934977

 * @summary Test MappedByteBuffer operations after mapped bye buffer becomes

 *   inaccessible

 * @run main/othervm Truncate

 */

import java.io.*;

import java.nio.*;

import java.nio.channels.*;

import java.util.concurrent.Callable;

public class Truncate {

    static final long INITIAL_FILE_SIZE   = 32000L;

    static final long TRUNCATED_FILE_SIZE =   512L;

    public static void main(String[] args) throws Exception {

        File blah = File.createTempFile("blah", null);

        blah.deleteOnExit();

        final FileChannel fc = new RandomAccessFile(blah, "rw").getChannel();

        fc.position(INITIAL_FILE_SIZE).write(ByteBuffer.wrap("THE END".getBytes()));

        final MappedByteBuffer mbb =

            fc.map(FileChannel.MapMode.READ_WRITE, 0, fc.size());

        boolean truncated;

        try {

            fc.truncate(TRUNCATED_FILE_SIZE);

            truncated = true;

        } catch (IOException ioe) {

            // probably on Windows where a file cannot be truncated when

            // there is a file mapping.

            truncated = false;

        }

        if (truncated) {

            // Test 1: access region that is no longer accessible

            execute(new Callable<Void>() {

                public Void call() {

                    mbb.get((int)TRUNCATED_FILE_SIZE + 1);

                    mbb.put((int)TRUNCATED_FILE_SIZE + 2, (byte)123);

                    return null;

                }

            });

            // Test 2: load buffer into memory

            execute(new Callable<Void>() {

                public Void call() throws IOException {

                    mbb.load();

                    return null;

                }

            });

        }

        fc.close();

    }

    // Runs the given task in its own thread. If operating correcting the

    // the thread will terminate with an InternalError as the mapped buffer

    // is inaccessible.

    static void execute(final Callable<?> c) {

        Runnable r = new Runnable() {

            public void run() {

                try {

                    Object ignore = c.call();

                } catch (Exception ignore) {

                }

            }

        };

        Thread t = new Thread(r);

        t.start();

        try { t.join(); } catch (InterruptedException ignore) { }

    }

}