/*

 * 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

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 */

package jdk.internal.jrtfs;

import java.nio.file.DirectoryStream;

import java.nio.file.ClosedDirectoryStreamException;

import java.nio.file.DirectoryIteratorException;

import java.nio.file.NotDirectoryException;

import java.nio.file.Path;

import java.util.Iterator;

import java.util.Objects;

import java.util.NoSuchElementException;

import java.io.IOException;

/**

 * DirectoryStream implementation for jrt file system implementations.

 *

 * @implNote This class needs to maintain JDK 8 source compatibility.

 *

 * It is used internally in the JDK to implement jimage/jrtfs access,

 * but also compiled and delivered as part of the jrtfs.jar to support access

 * to the jimage file provided by the shipped JDK by tools running on JDK 8.

 */

final class JrtDirectoryStream implements DirectoryStream<Path> {

    private final JrtPath dir;

    private final DirectoryStream.Filter<? super Path> filter;

    private boolean isClosed;

    private Iterator<Path> itr;

    JrtDirectoryStream(JrtPath dir,

            DirectoryStream.Filter<? super java.nio.file.Path> filter)

            throws IOException

    {

        this.dir = dir;

        if (!dir.jrtfs.isDirectory(dir, true)) {  // sanity check

            throw new NotDirectoryException(dir.toString());

        }

        this.filter = filter;

    }

    @Override

    public synchronized Iterator<Path> iterator() {

        if (isClosed)

            throw new ClosedDirectoryStreamException();

        if (itr != null)

            throw new IllegalStateException("Iterator has already been returned");

        try {

            itr = dir.jrtfs.iteratorOf(dir, filter);

        } catch (IOException e) {

            throw new IllegalStateException(e);

        }

        return new Iterator<Path>() {

            @Override

            public boolean hasNext() {

                synchronized (JrtDirectoryStream.this) {

                    if (isClosed)

                        return false;

                    return itr.hasNext();

                }

            }

            @Override

            public Path next() {

                synchronized (JrtDirectoryStream.this) {

                    if (isClosed)

                        throw new NoSuchElementException();

                    return itr.next();

                }

            }

        };

    }

    @Override

    public synchronized void close() throws IOException {

        isClosed = true;

    }

}