1 /*
   2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package jdk.internal.jrtfs;
  26 
  27 import java.nio.file.DirectoryStream;
  28 import java.nio.file.ClosedDirectoryStreamException;
  29 import java.nio.file.DirectoryIteratorException;
  30 import java.nio.file.NotDirectoryException;
  31 import java.nio.file.Path;
  32 import java.util.Iterator;
  33 import java.util.Objects;
  34 import java.util.NoSuchElementException;
  35 import java.io.IOException;
  36 
  37 /**
  38  * DirectoryStream implementation for jrt file system implementations.
  39  *
  40  * @implNote This class needs to maintain JDK 8 source compatibility.
  41  *
  42  * It is used internally in the JDK to implement jimage/jrtfs access,
  43  * but also compiled and delivered as part of the jrtfs.jar to support access
  44  * to the jimage file provided by the shipped JDK by tools running on JDK 8.
  45  */
  46 final class JrtDirectoryStream implements DirectoryStream<Path> {
  47 
  48     private final JrtPath dir;
  49     private final DirectoryStream.Filter<? super Path> filter;
  50     private volatile boolean isClosed;
  51     private volatile Iterator<Path> itr;
  52 
  53     JrtDirectoryStream(JrtPath dir,
  54             DirectoryStream.Filter<? super java.nio.file.Path> filter)
  55             throws IOException
  56     {
  57         this.dir = dir;
  58         if (!dir.jrtfs.isDirectory(dir, true)) {  // sanity check
  59             throw new NotDirectoryException(dir.toString());
  60         }
  61         this.filter = filter;
  62     }
  63 
  64     @Override
  65     public synchronized Iterator<Path> iterator() {
  66         if (isClosed)
  67             throw new ClosedDirectoryStreamException();
  68         if (itr != null)
  69             throw new IllegalStateException("Iterator has already been returned");
  70         try {
  71             itr = dir.jrtfs.iteratorOf(dir, filter);
  72         } catch (IOException e) {
  73             throw new IllegalStateException(e);
  74         }
  75         return new Iterator<Path>() {
  76             private Path next;
  77             @Override
  78             public synchronized boolean hasNext() {
  79                 if (isClosed)
  80                     return false;
  81                 return itr.hasNext();
  82             }
  83 
  84             @Override
  85             public synchronized Path next() {
  86                 if (isClosed)
  87                     throw new NoSuchElementException();
  88                 return itr.next();
  89             }
  90 
  91             @Override
  92             public void remove() {
  93                 throw new UnsupportedOperationException();
  94             }
  95         };
  96     }
  97 
  98     @Override
  99     public synchronized void close() throws IOException {
 100         isClosed = true;
 101     }
 102 }