content: /*
   * Copyright (c) 2022, 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 javac.internal.jrtfs;
  
  import java.nio.file.DirectoryStream;
  import java.nio.file.ClosedDirectoryStreamException;
  import java.nio.file.NotDirectoryException;
  import java.nio.file.Path;
  import java.util.Iterator;
  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;
      }
  }
  