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 io.netty.handler.stream;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.channel.ChannelHandlerContext;
20
21 import java.io.InputStream;
22 import java.io.PushbackInputStream;
23
24 /**
25 * A {@link ChunkedInput} that fetches data from an {@link InputStream} chunk by
26 * chunk.
27 * <p>
28 * Please note that the {@link InputStream} instance that feeds data into
29 * {@link ChunkedStream} must implement {@link InputStream#available()} as
30 * accurately as possible, rather than using the default implementation.
31 * Otherwise, {@link ChunkedStream} will generate many too small chunks or
32 * block unnecessarily often.
33 */
34 public class ChunkedStream implements ChunkedInput<ByteBuf> {
35
36 static final int DEFAULT_CHUNK_SIZE = 8192;
37
38 private final PushbackInputStream in;
39 private final int chunkSize;
40 private long offset;
41 private boolean closed;
42
43 /**
44 * Creates a new instance that fetches data from the specified stream.
45 */
46 public ChunkedStream(InputStream in) {
47 this(in, DEFAULT_CHUNK_SIZE);
48 }
49
50 /**
51 * Creates a new instance that fetches data from the specified stream.
52 *
53 * @param chunkSize the number of bytes to fetch on each
54 * {@link #readChunk(ChannelHandlerContext)} call
55 */
56 public ChunkedStream(InputStream in, int chunkSize) {
57 if (in == null) {
58 throw new NullPointerException("in");
59 }
60 if (chunkSize <= 0) {
61 throw new IllegalArgumentException(
62 "chunkSize: " + chunkSize +
63 " (expected: a positive integer)");
64 }
65
66 if (in instanceof PushbackInputStream) {
67 this.in = (PushbackInputStream) in;
68 } else {
69 this.in = new PushbackInputStream(in);
70 }
71 this.chunkSize = chunkSize;
72 }
73
74 /**
75 * Returns the number of transferred bytes.
76 */
77 public long transferredBytes() {
78 return offset;
79 }
80
81 @Override
82 public boolean isEndOfInput() throws Exception {
83 if (closed) {
84 return true;
85 }
86
87 int b = in.read();
88 if (b < 0) {
89 return true;
90 } else {
91 in.unread(b);
92 return false;
93 }
94 }
95
96 @Override
97 public void close() throws Exception {
98 closed = true;
99 in.close();
100 }
101
102 @Override
103 public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception {
104 if (isEndOfInput()) {
105 return null;
106 }
107
108 final int availableBytes = in.available();
109 final int chunkSize;
110 if (availableBytes <= 0) {
111 chunkSize = this.chunkSize;
112 } else {
113 chunkSize = Math.min(this.chunkSize, in.available());
114 }
115
116 boolean release = true;
117 ByteBuf buffer = ctx.alloc().buffer(chunkSize);
118 try {
119 // transfer to buffer
120 offset += buffer.writeBytes(in, chunkSize);
121 release = false;
122 return buffer;
123 } finally {
124 if (release) {
125 buffer.release();
126 }
127 }
128 }
129 }