/*

 * 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.attribute.*;

import java.io.IOException;

import sun.misc.Unsafe;

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

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

/**

 * Linux implementation of DosFileAttributeView for use on file systems such

 * as ext3 that have extended attributes enabled and SAMBA configured to store

 * DOS attributes.

 */

class LinuxDosFileAttributeView

    extends UnixFileAttributeViews.Basic implements DosFileAttributeView

{

    private static final Unsafe unsafe = Unsafe.getUnsafe();

    private static final String READONLY_NAME = "readonly";

    private static final String ARCHIVE_NAME = "archive";

    private static final String SYSTEM_NAME = "system";

    private static final String HIDDEN_NAME = "hidden";

    private static final String DOS_XATTR_NAME = "user.DOSATTRIB";

    private static final byte[] DOS_XATTR_NAME_AS_BYTES = DOS_XATTR_NAME.getBytes();

    private static final int DOS_XATTR_READONLY = 0x01;

    private static final int DOS_XATTR_HIDDEN   = 0x02;

    private static final int DOS_XATTR_SYSTEM   = 0x04;

    private static final int DOS_XATTR_ARCHIVE  = 0x20;

    LinuxDosFileAttributeView(UnixPath file, boolean followLinks) {

        super(file, followLinks);

    }

    @Override

    public String name() {

        return "dos";

    }

    @Override

    public Object getAttribute(String attribute) throws IOException {

        if (attribute.equals(READONLY_NAME))

            return readAttributes().isReadOnly();

        if (attribute.equals(ARCHIVE_NAME))

            return readAttributes().isArchive();

        if (attribute.equals(SYSTEM_NAME))

            return readAttributes().isSystem();

        if (attribute.equals(HIDDEN_NAME))

            return readAttributes().isHidden();

        return super.getAttribute(attribute);

    }

    @Override

    public void setAttribute(String attribute, Object value)

        throws IOException

    {

        if (attribute.equals(READONLY_NAME)) {

            setReadOnly((Boolean)value);

            return;

        }

        if (attribute.equals(ARCHIVE_NAME)) {

            setArchive((Boolean)value);

            return;

        }

        if (attribute.equals(SYSTEM_NAME)) {

            setSystem((Boolean)value);

            return;

        }

        if (attribute.equals(HIDDEN_NAME)) {

            setHidden((Boolean)value);

            return;

        }

        super.setAttribute(attribute, value);

    }

    @Override

        throws IOException

    {

        DosFileAttributes attrs = readAttributes();

        addBasicAttributesToBuilder(attrs, builder);

        if (builder.match(READONLY_NAME))

            builder.add(READONLY_NAME, attrs.isReadOnly());

        if (builder.match(ARCHIVE_NAME))

            builder.add(ARCHIVE_NAME, attrs.isArchive());

        if (builder.match(SYSTEM_NAME))

            builder.add(SYSTEM_NAME, attrs.isSystem());

        if (builder.match(HIDDEN_NAME))

            builder.add(HIDDEN_NAME, attrs.isHidden());

        return builder.unmodifiableMap();

    }

    @Override

    public DosFileAttributes readAttributes() throws IOException {

        file.checkRead();

        int fd = file.openForAttributeAccess(followLinks);

        try {

             final UnixFileAttributes attrs = UnixFileAttributes.get(fd);

             final int dosAttribute = getDosAttribute(fd);

             return new DosFileAttributes() {

                @Override

                    return attrs.lastModifiedTime();

                }

                @Override

                    return attrs.lastAccessTime();

                }

                @Override

                    return attrs.creationTime();

                }

                @Override

                public boolean isRegularFile() {

                    return attrs.isRegularFile();

                }

                @Override

                public boolean isDirectory() {

                    return attrs.isDirectory();

                }

                @Override

                public boolean isSymbolicLink() {

                    return attrs.isSymbolicLink();

                }

                @Override

                public boolean isOther() {

                    return attrs.isOther();

                }

                @Override

                public long size() {

                    return attrs.size();

                }

                @Override

                public Object fileKey() {

                    return attrs.fileKey();

                }

                @Override

                public boolean isReadOnly() {

                    return (dosAttribute & DOS_XATTR_READONLY) != 0;

                }

                @Override

                public boolean isHidden() {

                    return (dosAttribute & DOS_XATTR_HIDDEN) != 0;

                }

                @Override

                public boolean isArchive() {

                    return (dosAttribute & DOS_XATTR_ARCHIVE) != 0;

                }

                @Override

                public boolean isSystem() {

                    return (dosAttribute & DOS_XATTR_SYSTEM) != 0;

                }

             };

        } catch (UnixException x) {

            x.rethrowAsIOException(file);

            return null;    // keep compiler happy

        } finally {

            close(fd);

        }

    }

    @Override

    public void setReadOnly(boolean value) throws IOException {

        updateDosAttribute(DOS_XATTR_READONLY, value);

    }

    @Override

    public void setHidden(boolean value) throws IOException {

        updateDosAttribute(DOS_XATTR_HIDDEN, value);

    }

    @Override

    public void setArchive(boolean value) throws IOException {

        updateDosAttribute(DOS_XATTR_ARCHIVE, value);

    }

    @Override

    public void setSystem(boolean value) throws IOException {

        updateDosAttribute(DOS_XATTR_SYSTEM, value);

    }

    /**

     * Reads the value of the user.DOSATTRIB extended attribute

     */

    private int getDosAttribute(int fd) throws UnixException {

        final int size = 24;

        NativeBuffer buffer = NativeBuffers.getNativeBuffer(size);

        try {

            int len = LinuxNativeDispatcher

                .fgetxattr(fd, DOS_XATTR_NAME_AS_BYTES, buffer.address(), size);

            if (len > 0) {

                // ignore null terminator

                if (unsafe.getByte(buffer.address()+len-1) == 0)

                    len--;

                // convert to String and parse

                byte[] buf = new byte[len];

                unsafe.copyMemory(null, buffer.address(), buf,

                    Unsafe.ARRAY_BYTE_BASE_OFFSET, len);

                String value = new String(buf); // platform encoding

                // should be something like 0x20

                if (value.length() >= 3 && value.startsWith("0x")) {

                    try {

                        return Integer.parseInt(value.substring(2), 16);

                    } catch (NumberFormatException x) {

                        // ignore

                    }

                }

            }

            throw new UnixException("Value of " + DOS_XATTR_NAME + " attribute is invalid");

        } catch (UnixException x) {

            // default value when attribute does not exist

            if (x.errno() == ENODATA)

                return 0;

            throw x;

        } finally {

            buffer.release();

        }

    }

    /**

     * Updates the value of the user.DOSATTRIB extended attribute

     */

    private void updateDosAttribute(int flag, boolean enable) throws IOException {

        file.checkWrite();

        int fd = file.openForAttributeAccess(followLinks);

        try {

            int oldValue = getDosAttribute(fd);

            int newValue = oldValue;

            if (enable) {

                newValue |= flag;

            } else {

                newValue &= ~flag;

            }

            if (newValue != oldValue) {

                byte[] value = ("0x" + Integer.toHexString(newValue)).getBytes();

                NativeBuffer buffer = NativeBuffers.asNativeBuffer(value);

                try {

                    LinuxNativeDispatcher.fsetxattr(fd, DOS_XATTR_NAME_AS_BYTES,

                        buffer.address(), value.length+1);

                } finally {

                    buffer.release();

                }

            }

        } catch (UnixException x) {

            x.rethrowAsIOException(file);

        } finally {

            close(fd);

        }

    }

}