/*

 * Copyright (c) 2014, 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.  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 jdk.internal.jrtfs;

import java.io.*;

import java.nio.channels.*;

import java.nio.file.*;

import java.nio.file.DirectoryStream.Filter;

import java.nio.file.attribute.*;

import java.nio.file.spi.FileSystemProvider;

import java.net.URI;

import java.net.URISyntaxException;

import java.util.HashMap;

import java.util.Map;

import java.util.Set;

import java.util.concurrent.ExecutorService;

public final class JrtFileSystemProvider extends FileSystemProvider {

    private volatile FileSystem theFileSystem;

    public JrtFileSystemProvider() { }

    @Override

    public String getScheme() {

        return "jrt";

    }

    /**

     * Need FilePermission ${java.home}/-", "read" to create or get jrt:/

     */

    private void checkPermission() {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            String home = SystemImages.RUNTIME_HOME;

            FilePermission perm =

                new FilePermission(home + File.separator + "-", "read");

            sm.checkPermission(perm);

        }

    }

    private void checkUri(URI uri) {

        if (!uri.getScheme().equalsIgnoreCase(getScheme()))

            throw new IllegalArgumentException("URI does not match this provider");

        if (uri.getAuthority() != null)

            throw new IllegalArgumentException("Authority component present");

        if (uri.getPath() == null)

            throw new IllegalArgumentException("Path component is undefined");

        if (!uri.getPath().equals("/"))

            throw new IllegalArgumentException("Path component should be '/'");

        if (uri.getQuery() != null)

            throw new IllegalArgumentException("Query component present");

        if (uri.getFragment() != null)

            throw new IllegalArgumentException("Fragment component present");

    }

    @Override

    public FileSystem newFileSystem(URI uri, Map<String, ?> env)

        throws IOException

    {

        checkPermission();

        checkUri(uri);

        return new JrtFileSystem(this, env);

    }

    @Override

    public Path getPath(URI uri) {

        checkPermission();

        if (!uri.getScheme().equalsIgnoreCase(getScheme()))

            throw new IllegalArgumentException("URI does not match this provider");

        if (uri.getAuthority() != null)

            throw new IllegalArgumentException("Authority component present");

        if (uri.getQuery() != null)

            throw new IllegalArgumentException("Query component present");

        if (uri.getFragment() != null)

            throw new IllegalArgumentException("Fragment component present");

        String path = uri.getPath();

        if (path == null || path.charAt(0) != '/')

            throw new IllegalArgumentException("Invalid path component");

        return getTheFileSystem().getPath(path);

    }

    private FileSystem getTheFileSystem() {

        checkPermission();

        FileSystem fs = this.theFileSystem;

        if (fs == null) {

            synchronized (this) {

                fs = this.theFileSystem;

                if (fs == null) {

                    try {

                        this.theFileSystem = fs = new JrtFileSystem(this, null) {

                            @Override public void close() {

                                throw new UnsupportedOperationException();

                            }

                        };

                    } catch (IOException ioe) {

                        throw new InternalError(ioe);

                    }

                }

            }

        }

        return fs;

    }

    @Override

    public FileSystem getFileSystem(URI uri) {

        checkPermission();

        checkUri(uri);

        return getTheFileSystem();

    }

    // Checks that the given file is a JrtPath

    static final JrtPath toJrtPath(Path path) {

        if (path == null)

            throw new NullPointerException();

        if (!(path instanceof JrtPath))

            throw new ProviderMismatchException();

        return (JrtPath)path;

    }

    @Override

    public void checkAccess(Path path, AccessMode... modes) throws IOException {

        toJrtPath(path).checkAccess(modes);

    }

    @Override

    public void copy(Path src, Path target, CopyOption... options)

        throws IOException

    {

        toJrtPath(src).copy(toJrtPath(target), options);

    }

    @Override

    public void createDirectory(Path path, FileAttribute<?>... attrs)

        throws IOException

    {

        toJrtPath(path).createDirectory(attrs);

    }

    @Override

    public final void delete(Path path) throws IOException {

        toJrtPath(path).delete();

    }

    @Override

    @SuppressWarnings("unchecked")

    public <V extends FileAttributeView> V

        getFileAttributeView(Path path, Class<V> type, LinkOption... options)

    {

        return JrtFileAttributeView.get(toJrtPath(path), type);

    }

    @Override

    public FileStore getFileStore(Path path) throws IOException {

        return toJrtPath(path).getFileStore();

    }

    @Override

    public boolean isHidden(Path path) {

        return toJrtPath(path).isHidden();

    }

    @Override

    public boolean isSameFile(Path path, Path other) throws IOException {

        return toJrtPath(path).isSameFile(other);

    }

    @Override

    public void move(Path src, Path target, CopyOption... options)

        throws IOException

    {

        toJrtPath(src).move(toJrtPath(target), options);

    }

    @Override

    public AsynchronousFileChannel newAsynchronousFileChannel(Path path,

            Set<? extends OpenOption> options,

            ExecutorService exec,

            FileAttribute<?>... attrs)

            throws IOException

    {

        throw new UnsupportedOperationException();

    }

    @Override

    public SeekableByteChannel newByteChannel(Path path,

                                              Set<? extends OpenOption> options,

                                              FileAttribute<?>... attrs)

        throws IOException

    {

        return toJrtPath(path).newByteChannel(options, attrs);

    }

    @Override

    public DirectoryStream<Path> newDirectoryStream(

        Path path, Filter<? super Path> filter) throws IOException

    {

        return toJrtPath(path).newDirectoryStream(filter);

    }

    @Override

    public FileChannel newFileChannel(Path path,

                                      Set<? extends OpenOption> options,

                                      FileAttribute<?>... attrs)

        throws IOException

    {

        return toJrtPath(path).newFileChannel(options, attrs);

    }

    @Override

    public InputStream newInputStream(Path path, OpenOption... options)

        throws IOException

    {

        return toJrtPath(path).newInputStream(options);

    }

    @Override

    public OutputStream newOutputStream(Path path, OpenOption... options)

        throws IOException

    {

        return toJrtPath(path).newOutputStream(options);

    }

    @Override

    @SuppressWarnings("unchecked") // Cast to A

    public <A extends BasicFileAttributes> A

        readAttributes(Path path, Class<A> type, LinkOption... options)

        throws IOException

    {

        if (type == BasicFileAttributes.class || type == JrtFileAttributes.class)

            return (A)toJrtPath(path).getAttributes();

        return null;

    }

    @Override

    public Map<String, Object>

        readAttributes(Path path, String attribute, LinkOption... options)

        throws IOException

    {

        return toJrtPath(path).readAttributes(attribute, options);

    }

    @Override

    public void setAttribute(Path path, String attribute,

                             Object value, LinkOption... options)

        throws IOException

    {

        toJrtPath(path).setAttribute(attribute, value, options);

    }

}