1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the 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 public class ChunkedFile implements ChunkedInput {
34
35 private final RandomAccessFile file;
36 private final long startOffset;
37 private final long endOffset;
38 private final int chunkSize;
39 private long offset;
40
41 /**
42 * Creates a new instance that fetches data from the specified file.
43 */
44 public ChunkedFile(File file) throws IOException {
45 this(file, ChunkedStream.DEFAULT_CHUNK_SIZE);
46 }
47
48 /**
49 * Creates a new instance that fetches data from the specified file.
50 *
51 * @param chunkSize the number of bytes to fetch on each
52 * {@link #nextChunk()} call
53 */
54 public ChunkedFile(File file, int chunkSize) throws IOException {
55 this(new RandomAccessFile(file, "r"), chunkSize);
56 }
57
58 /**
59 * Creates a new instance that fetches data from the specified file.
60 */
61 public ChunkedFile(RandomAccessFile file) throws IOException {
62 this(file, ChunkedStream.DEFAULT_CHUNK_SIZE);
63 }
64
65 /**
66 * Creates a new instance that fetches data from the specified file.
67 *
68 * @param chunkSize the number of bytes to fetch on each
69 * {@link #nextChunk()} call
70 */
71 public ChunkedFile(RandomAccessFile file, int chunkSize) throws IOException {
72 this(file, 0, file.length(), chunkSize);
73 }
74
75 /**
76 * Creates a new instance that fetches data from the specified file.
77 *
78 * @param offset the offset of the file where the transfer begins
79 * @param length the number of bytes to transfer
80 * @param chunkSize the number of bytes to fetch on each
81 * {@link #nextChunk()} call
82 */
83 public ChunkedFile(RandomAccessFile file, long offset, long length, int chunkSize) throws IOException {
84 if (file == null) {
85 throw new NullPointerException("file");
86 }
87 if (offset < 0) {
88 throw new IllegalArgumentException(
89 "offset: " + offset + " (expected: 0 or greater)");
90 }
91 if (length < 0) {
92 throw new IllegalArgumentException(
93 "length: " + length + " (expected: 0 or greater)");
94 }
95 if (chunkSize <= 0) {
96 throw new IllegalArgumentException(
97 "chunkSize: " + chunkSize +
98 " (expected: a positive integer)");
99 }
100
101 this.file = file;
102 this.offset = startOffset = offset;
103 endOffset = offset + length;
104 this.chunkSize = chunkSize;
105
106 file.seek(offset);
107 }
108
109 /**
110 * Returns the offset in the file where the transfer began.
111 */
112 public long getStartOffset() {
113 return startOffset;
114 }
115
116 /**
117 * Returns the offset in the file where the transfer will end.
118 */
119 public long getEndOffset() {
120 return endOffset;
121 }
122
123 /**
124 * Returns the offset in the file where the transfer is happening currently.
125 */
126 public long getCurrentOffset() {
127 return offset;
128 }
129
130 public boolean hasNextChunk() throws Exception {
131 return offset < endOffset && file.getChannel().isOpen();
132 }
133
134 public boolean isEndOfInput() throws Exception {
135 return !hasNextChunk();
136 }
137
138 public void close() throws Exception {
139 file.close();
140 }
141
142 public Object nextChunk() throws Exception {
143 long offset = this.offset;
144 if (offset >= endOffset) {
145 return null;
146 }
147
148 int chunkSize = (int) Math.min(this.chunkSize, endOffset - offset);
149 byte[] chunk = new byte[chunkSize];
150 file.readFully(chunk);
151 this.offset = offset + chunkSize;
152 return wrappedBuffer(chunk);
153 }
154 }