1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.handler.stream;
17
18 import static org.jboss.netty.buffer.ChannelBuffers.*;
19
20 import java.io.File;
21 import java.io.IOException;
22 import java.io.RandomAccessFile;
23
24 import org.jboss.netty.channel.FileRegion;
25
26 /**
27 * A {@link ChunkedInput} that fetches data from a file chunk by chunk.
28 * <p>
29 * If your operating system supports
30 * <a href="http://en.wikipedia.org/wiki/Zero-copy">zero-copy file transfer</a>
31 * such as {@code sendfile()}, you might want to use {@link FileRegion} instead.
32 *
33 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
34 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
35 * @version $Rev: 2243 $, $Date: 2010-04-16 14:01:55 +0900 (Fri, 16 Apr 2010) $
36 */
37 public class ChunkedFile implements ChunkedInput {
38
39 private final RandomAccessFile file;
40 private final long startOffset;
41 private final long endOffset;
42 private final int chunkSize;
43 private volatile long offset;
44
45 /**
46 * Creates a new instance that fetches data from the specified file.
47 */
48 public ChunkedFile(File file) throws IOException {
49 this(file, ChunkedStream.DEFAULT_CHUNK_SIZE);
50 }
51
52 /**
53 * Creates a new instance that fetches data from the specified file.
54 *
55 * @param chunkSize the number of bytes to fetch on each
56 * {@link #nextChunk()} call
57 */
58 public ChunkedFile(File file, int chunkSize) throws IOException {
59 this(new RandomAccessFile(file, "r"), chunkSize);
60 }
61
62 /**
63 * Creates a new instance that fetches data from the specified file.
64 */
65 public ChunkedFile(RandomAccessFile file) throws IOException {
66 this(file, ChunkedStream.DEFAULT_CHUNK_SIZE);
67 }
68
69 /**
70 * Creates a new instance that fetches data from the specified file.
71 *
72 * @param chunkSize the number of bytes to fetch on each
73 * {@link #nextChunk()} call
74 */
75 public ChunkedFile(RandomAccessFile file, int chunkSize) throws IOException {
76 this(file, 0, file.length(), chunkSize);
77 }
78
79 /**
80 * Creates a new instance that fetches data from the specified file.
81 *
82 * @param offset the offset of the file where the transfer begins
83 * @param length the number of bytes to transfer
84 * @param chunkSize the number of bytes to fetch on each
85 * {@link #nextChunk()} call
86 */
87 public ChunkedFile(RandomAccessFile file, long offset, long length, int chunkSize) throws IOException {
88 if (file == null) {
89 throw new NullPointerException("file");
90 }
91 if (offset < 0) {
92 throw new IllegalArgumentException(
93 "offset: " + offset + " (expected: 0 or greater)");
94 }
95 if (length < 0) {
96 throw new IllegalArgumentException(
97 "length: " + length + " (expected: 0 or greater)");
98 }
99 if (chunkSize <= 0) {
100 throw new IllegalArgumentException(
101 "chunkSize: " + chunkSize +
102 " (expected: a positive integer)");
103 }
104
105 this.file = file;
106 this.offset = startOffset = offset;
107 endOffset = offset + length;
108 this.chunkSize = chunkSize;
109
110 file.seek(offset);
111 }
112
113 /**
114 * Returns the offset in the file where the transfer began.
115 */
116 public long getStartOffset() {
117 return startOffset;
118 }
119
120 /**
121 * Returns the offset in the file where the transfer will end.
122 */
123 public long getEndOffset() {
124 return endOffset;
125 }
126
127 /**
128 * Returns the offset in the file where the transfer is happening currently.
129 */
130 public long getCurrentOffset() {
131 return offset;
132 }
133
134 public boolean hasNextChunk() throws Exception {
135 return offset < endOffset && file.getChannel().isOpen();
136 }
137
138 public boolean isEndOfInput() throws Exception {
139 return !hasNextChunk();
140 }
141
142 public void close() throws Exception {
143 file.close();
144 }
145
146 public Object nextChunk() throws Exception {
147 long offset = this.offset;
148 if (offset >= endOffset) {
149 return null;
150 }
151
152 int chunkSize = (int) Math.min(this.chunkSize, endOffset - offset);
153 byte[] chunk = new byte[chunkSize];
154 file.readFully(chunk);
155 this.offset = offset + chunkSize;
156 return wrappedBuffer(chunk);
157 }
158 }