/*

 * 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 com.sun.xml.internal.org.jvnet.mimepull;

import java.io.File;

import java.io.IOException;

import java.io.RandomAccessFile;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.List;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 * Removing files based on this

 * <a href="http://java.sun.com/developer/technicalArticles/javase/finalization/">article</a>

 *

 * @author Jitendra Kotamraju

 */

final class WeakDataFile extends WeakReference<DataFile> {

    private static final Logger LOGGER = Logger.getLogger(WeakDataFile.class.getName());

    //private static final int MAX_ITERATIONS = 2;

    private static ReferenceQueue<DataFile> refQueue = new ReferenceQueue<DataFile>();

    private static List<WeakDataFile> refList = new ArrayList<WeakDataFile>();

    private final File file;

    private final RandomAccessFile raf;

    private static boolean hasCleanUpExecutor = false;

    static {

        CleanUpExecutorFactory executorFactory = CleanUpExecutorFactory.newInstance();

        if (executorFactory!=null) {

            if (LOGGER.isLoggable(Level.FINE)) {

                LOGGER.log(Level.FINE, "Initializing clean up executor for MIMEPULL: {0}", executorFactory.getClass().getName());

            }

            hasCleanUpExecutor = true;

        }

    }

    WeakDataFile(DataFile df, File file) {

        super(df, refQueue);

        refList.add(this);

        this.file = file;

        try {

            raf = new RandomAccessFile(file, "rw");

        } catch(IOException ioe) {

            throw new MIMEParsingException(ioe);

        }

        if (!hasCleanUpExecutor) {

            drainRefQueueBounded();

        }

    }

    synchronized void read(long pointer, byte[] buf, int offset, int length ) {

        try {

            raf.seek(pointer);

            raf.readFully(buf, offset, length);

        } catch(IOException ioe) {

            throw new MIMEParsingException(ioe);

        }

    }

    synchronized long writeTo(long pointer, byte[] data, int offset, int length) {

        try {

            raf.seek(pointer);

            raf.write(data, offset, length);

            return raf.getFilePointer();    // Update pointer for next write

        } catch(IOException ioe) {

            throw new MIMEParsingException(ioe);

        }

    }

    void close() {

        if (LOGGER.isLoggable(Level.FINE)) {

            LOGGER.log(Level.FINE, "Deleting file = {0}", file.getName());

        }

        refList.remove(this);

        try {

            raf.close();

            boolean deleted = file.delete();

            if (!deleted) {

                if (LOGGER.isLoggable(Level.INFO)) {

                    LOGGER.log(Level.INFO, "File {0} was not deleted", file.getAbsolutePath());

                }

            }

        } catch(IOException ioe) {

            throw new MIMEParsingException(ioe);

        }

    }

    void renameTo(File f) {

        if (LOGGER.isLoggable(Level.FINE)) {

            LOGGER.log(Level.FINE, "Moving file={0} to={1}", new Object[]{file, f});

        }

        refList.remove(this);

        try {

            raf.close();

            boolean renamed = file.renameTo(f);

            if (!renamed) {

                if (LOGGER.isLoggable(Level.INFO)) {

                    LOGGER.log(Level.INFO, "File {0} was not moved to {1}", new Object[] {file.getAbsolutePath(), f.getAbsolutePath()});

                }

            }

        } catch(IOException ioe) {

            throw new MIMEParsingException(ioe);

        }

    }

    static void drainRefQueueBounded() {

        WeakDataFile weak;

        while (( weak = (WeakDataFile) refQueue.poll()) != null ) {

            if (LOGGER.isLoggable(Level.FINE)) {

                LOGGER.log(Level.FINE, "Cleaning file = {0} from reference queue.", weak.file);

            }

            weak.close();

        }

    }

}