/*

 * Copyright 2008-2009 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.nio.fs;

import java.nio.file.*;

import java.nio.file.attribute.*;

import java.io.IOException;

import java.util.*;

import java.security.AccessController;

import sun.security.action.GetPropertyAction;

import static sun.nio.fs.LinuxNativeDispatcher.*;

/**

 * Linux implementation of FileSystem

 */

class LinuxFileSystem extends UnixFileSystem {

    private final boolean hasInotify;

    private final boolean hasAtSysCalls;

    LinuxFileSystem(UnixFileSystemProvider provider, String dir) {

        super(provider, dir);

        // assume X.Y[-Z] format

        String osversion = AccessController

            .doPrivileged(new GetPropertyAction("os.version"));

        String[] vers = osversion.split("\\.", 0);

        assert vers.length >= 2;

        int majorVersion = Integer.parseInt(vers[0]);

        int minorVersion = Integer.parseInt(vers[1]);

        int microVersion = 0;

        if (vers.length > 2) {

            String[] microVers = vers[2].split("-", 0);

            microVersion = (microVers.length > 0) ?

                Integer.parseInt(microVers[0]) : 0;

        }

        // inotify available since 2.6.13

        this.hasInotify = ((majorVersion > 2) ||

            (majorVersion == 2 && minorVersion > 6) ||

            ((majorVersion == 2) && (minorVersion == 6) && (microVersion >= 13)));

        // openat etc. available since 2.6.16

        this.hasAtSysCalls = ((majorVersion > 2) ||

            (majorVersion == 2 && minorVersion > 6) ||

            ((majorVersion == 2) && (minorVersion == 6) && (microVersion >= 16)));

    }

    @Override

    public WatchService newWatchService()

        throws IOException

    {

        if (hasInotify) {

            return new LinuxWatchService(this);

        } else {

            // use polling implementation on older kernels

            return new PollingWatchService();

        }

    }

    @Override

    @SuppressWarnings("unchecked")

    public <V extends FileAttributeView> V newFileAttributeView(Class<V> view,

                                                                UnixPath file,

                                                                LinkOption... options)

    {

        if (view == DosFileAttributeView.class)

            return (V) new LinuxDosFileAttributeView(file, followLinks(options));

        if (view == UserDefinedFileAttributeView.class)

            return (V) new LinuxUserDefinedFileAttributeView(file, followLinks(options));

        return super.newFileAttributeView(view, file, options);

    }

    @Override

    @SuppressWarnings("unchecked")

    public FileAttributeView newFileAttributeView(String name,

                                                  UnixPath file,

                                                  LinkOption... options)

    {

        if (name.equals("dos"))

            return new LinuxDosFileAttributeView(file, followLinks(options));

        if (name.equals("xattr"))

            return new LinuxUserDefinedFileAttributeView(file, followLinks(options));

        return super.newFileAttributeView(name, file, options);

    }

    // lazy initialization of the list of supported attribute views

    private static class SupportedFileFileAttributeViewsHolder {

        static final Set<String> supportedFileAttributeViews =

            supportedFileAttributeViews();

        private static Set<String> supportedFileAttributeViews() {

            Set<String> result = new HashSet<String>();

            result.addAll(UnixFileSystem.standardFileAttributeViews());

            // additional Linux-specific views

            result.add("dos");

            result.add("xattr");

            return Collections.unmodifiableSet(result);

        }

    }

    @Override

    public Set<String> supportedFileAttributeViews() {

        return SupportedFileFileAttributeViewsHolder.supportedFileAttributeViews;

    }

    @Override

    void copyNonPosixAttributes(int ofd, int nfd) {

        LinuxUserDefinedFileAttributeView.copyExtendedAttributes(ofd, nfd);

    }

    @Override

    boolean supportsSecureDirectoryStreams() {

        return hasAtSysCalls;

    }

    /**

     * Returns object to iterate over entries in /etc/mtab

     */

    @Override

    Iterable<UnixMountEntry> getMountEntries() {

        ArrayList<UnixMountEntry> entries = new ArrayList<UnixMountEntry>();

        try {

            long fp = setmntent("/etc/mtab".getBytes(), "r".getBytes());

            try {

                for (;;) {

                    UnixMountEntry entry = new UnixMountEntry();

                    int res = getextmntent(fp, entry);

                    if (res < 0)

                        break;

                    entries.add(entry);

                }

            } finally {

                endmntent(fp);

            }

        } catch (UnixException x) {

            // nothing we can do

        }

        return entries;

    }

    @Override

    FileStore getFileStore(UnixPath path) throws IOException {

        return new LinuxFileStore(path);

    }

    @Override

    FileStore getFileStore(UnixMountEntry entry) throws IOException {

        return new LinuxFileStore(this, entry);

    }

}