1 /* 2 * Copyright (c) 2012, 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.FileNotFoundException; 29 import java.io.IOException; 30 import java.nio.ByteBuffer; 31 import java.nio.channels.FileChannel; 32 import java.nio.channels.ReadableByteChannel; 33 import java.util.ArrayList; 34 import java.util.Iterator; 35 import java.util.List; 36 37 final class ChunksChannel implements ReadableByteChannel { 38 private final Iterator<RepositoryChunk> chunks; 39 private RepositoryChunk current; 40 private ReadableByteChannel channel; 41 42 public ChunksChannel(List<RepositoryChunk> chunks) throws IOException { 43 if (chunks.isEmpty()) { 44 throw new FileNotFoundException("No chunks"); 45 } 46 List<RepositoryChunk> l = new ArrayList<>(chunks.size()); 47 for (RepositoryChunk c : chunks) { 48 c.use(); // keep alive while we're reading. 49 l.add(c); 50 } 51 this.chunks = l.iterator(); 52 nextChannel(); 53 } 54 55 private boolean nextChunk() { 56 if (!chunks.hasNext()) { 57 return false; 58 } 59 current = chunks.next(); 60 return true; 61 } 62 63 private boolean nextChannel() throws IOException { 64 if (!nextChunk()) { 65 return false; 66 } 67 68 channel = current.newChannel(); 69 return true; 70 } 71 72 @Override 73 public int read(ByteBuffer dst) throws IOException { 74 for (;;) { 75 if (channel != null) { 76 assert current != null; 77 int r = channel.read(dst); 78 if (r != -1) { 79 return r; 80 } 81 channel.close(); 82 current.release(); 83 channel = null; 84 current = null; 85 } 86 if (!nextChannel()) { 87 return -1; 88 } 89 } 90 } 91 92 public long transferTo(FileChannel out) throws IOException { 93 long pos = 0; 94 for (;;) { 95 if (channel != null) { 96 assert current != null; 97 98 long rem = current.getSize(); 99 100 while (rem > 0) { 101 long n = Math.min(rem, 1024 * 1024); 102 long w = out.transferFrom(channel, pos, n); 103 pos += w; 104 rem -= w; 105 } 106 107 channel.close(); 108 current.release(); 109 110 channel = null; 111 current = null; 112 } 113 if (!nextChannel()) { 114 return pos; 115 } 116 } 117 } 118 119 @Override 120 public void close() throws IOException { 121 if (channel != null) { 122 channel.close(); 123 channel = null; 124 } 125 while (current != null) { 126 current.release(); 127 current = null; 128 if (!nextChunk()) { 129 return; 130 } 131 } 132 } 133 134 @Override 135 public boolean isOpen() { 136 return channel != null; 137 } 138 139 @Override 140 @SuppressWarnings("deprecation") 141 protected void finalize() throws Throwable { 142 super.finalize(); 143 close(); 144 } 145 }