1 /*
   2  * Copyright (c) 2001, 2019, 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.jfr.internal;
  27 
  28 import java.io.BufferedInputStream;
  29 import java.io.IOException;
  30 import java.io.InputStream;
  31 import java.util.ArrayList;
  32 import java.util.Iterator;
  33 import java.util.List;
  34 
  35 final class ChunkInputStream extends InputStream {
  36     private final Iterator<RepositoryChunk> chunks;
  37     private RepositoryChunk currentChunk;
  38     private InputStream stream;
  39 
  40     ChunkInputStream(List<RepositoryChunk> chunks) throws IOException {
  41         List<RepositoryChunk> l = new ArrayList<>(chunks.size());
  42         for (RepositoryChunk c : chunks) {
  43             c.use(); // keep alive while we're reading.
  44             l.add(c);
  45         }
  46 
  47         this.chunks = l.iterator();
  48         nextStream();
  49     }
  50 
  51     @Override
  52     public int available() throws IOException {
  53         if (stream != null) {
  54             return stream.available();
  55         }
  56         return 0;
  57     }
  58 
  59     private boolean nextStream() throws IOException {
  60         if (!nextChunk()) {
  61             return false;
  62         }
  63 
  64         stream = new BufferedInputStream(SecuritySupport.newFileInputStream(currentChunk.getFile()));
  65         return true;
  66     }
  67 
  68     private boolean nextChunk() {
  69         if (!chunks.hasNext()) {
  70             return false;
  71         }
  72         currentChunk = chunks.next();
  73         return true;
  74     }
  75 
  76     @Override
  77     public int read() throws IOException {
  78         while (true) {
  79             if (stream != null) {
  80                 int r = stream.read();
  81                 if (r != -1) {
  82                     return r;
  83                 }
  84                 stream.close();
  85                 currentChunk.release();
  86                 stream = null;
  87                 currentChunk = null;
  88             }
  89             if (!nextStream()) {
  90                 return -1;
  91             }
  92         }
  93     }
  94 
  95     @Override
  96     public void close() throws IOException {
  97         if (stream != null) {
  98             stream.close();
  99             stream = null;
 100         }
 101         while (currentChunk != null) {
 102             currentChunk.release();
 103             currentChunk = null;
 104             if (!nextChunk()) {
 105                 return;
 106             }
 107         }
 108     }
 109 
 110     @Override
 111     @SuppressWarnings("deprecation")
 112     protected void finalize() throws Throwable {
 113         super.finalize();
 114         close();
 115     }
 116 }