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 

    26 package jdk.internal.jrtfs;

    27 

    28 import java.nio.file.DirectoryStream;

    29 import java.nio.file.ClosedDirectoryStreamException;

    30 import java.nio.file.DirectoryIteratorException;

    31 import java.nio.file.NotDirectoryException;

    32 import java.nio.file.Path;

    33 import java.util.Iterator;

    34 import java.util.NoSuchElementException;

    35 import java.io.IOException;

    36 

    37 final class JrtDirectoryStream implements DirectoryStream<Path> {

    38     private final JrtFileSystem jrtfs;

    39     private final byte[] path;

    40     // prefix to be used for children of this directory

    41     // so that child path are reported relatively (if needed)

    42     private final String childPrefix;

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

    44     private volatile boolean isClosed;

    45     private volatile Iterator<Path> itr;

    46 

    47     JrtDirectoryStream(JrtPath jrtPath,

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

    49         throws IOException

    50     {

    51         this.jrtfs = jrtPath.getFileSystem();

    52         this.path = jrtPath.getResolvedPath();

    53         // sanity check

    54         if (!jrtfs.isDirectory(path))

    55             throw new NotDirectoryException(jrtPath.toString());

    56 

    57         // absolute path and does not have funky chars in front like /./java.base

    58         if (jrtPath.isAbsolute() && (path.length == jrtPath.getPathLength())) {

    59             childPrefix = null;

    60         } else {

    61             // cases where directory content needs to modified with prefix

    62             // like ./java.base, /./java.base, java.base and so on.

    63             String dirName = jrtPath.toString();

    64             int idx = dirName.indexOf(JrtFileSystem.getString(path).substring(1));

    65             childPrefix = dirName.substring(0, idx);

    66         }

    67         this.filter = filter;

    68     }

    69 

    70     @Override

    71     public synchronized Iterator<Path> iterator() {

    72         if (isClosed)

    73             throw new ClosedDirectoryStreamException();

    74         if (itr != null)

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

    76 

    77         try {

    78             itr = jrtfs.iteratorOf(path, childPrefix);

    79         } catch (IOException e) {

    80             throw new IllegalStateException(e);

    81         }

    82         return new Iterator<Path>() {

    83             /*

    84              * next Path value to return from this iterator.

    85              * null value means hasNext() not called yet

    86              * or last hasNext() returned false or resulted

    87              * in exception. If last hasNext() returned true,

    88              * then this field has non-null value.

    89              */

    90             private Path next;

    91 

    92             // get-and-clear and set-next by these methods

    93             private Path getAndClearNext() {

    94                 assert next != null;

    95                 Path result = this.next;

    96                 this.next = null;

    97                 return result;

    98             }

    99 

   100             private void setNext(Path path) {

   101                 assert path != null;

   102                 this.next = path;

   103             }

   104 

   105             // if hasNext() returns true, 'next' field has non-null Path

   106             @Override

   107             public synchronized boolean hasNext() {

   108                 if (next != null) {

   109                     return true;

   110                 }

   111 

   112                 if (isClosed) {

   113                     return false;

   114                 }

   115 

   116                 if (filter == null) {

   117                     if (itr.hasNext()) {

   118                         setNext(itr.next());

   119                         return true;

   120                     } else {

   121                         return false;

   122                     }

   123                 } else {

   124                     while (itr.hasNext()) {

   125                         Path tmpPath = itr.next();

   126                         try {

   127                             if (filter.accept(tmpPath)) {

   128                                 setNext(tmpPath);

   129                                 return true;

   130                             }

   131                         } catch (IOException ioe) {

   132                             throw new DirectoryIteratorException(ioe);

   133                         }

   134                     }

   135 

   136                     return false;

   137                 }

   138             }

   139 

   140             @Override

   141             public synchronized Path next() {

   142                 if (next != null) {

   143                     return getAndClearNext();

   144                 }

   145 

   146                 if (isClosed) {

   147                     throw new NoSuchElementException();

   148                 }

   149 

   150                 if (next == null && itr.hasNext()) {

   151                     // missing hasNext() between next() calls.

   152                     if (hasNext()) {

   153                         return getAndClearNext();

   154                     }

   155                 }

   156 

   157                 throw new NoSuchElementException();

   158             }

   159 

   160             @Override

   161             public void remove() {

   162                 throw new UnsupportedOperationException();

   163             }

   164         };

   165     }

   166 

   167     @Override

   168     public synchronized void close() throws IOException {

   169         isClosed = true;

   170     }

   171 }