1 //
2 // ========================================================================
3 // Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.spdy.api;
20
21 import java.nio.ByteBuffer;
22 import java.nio.charset.Charset;
23 import java.util.concurrent.atomic.AtomicInteger;
24
25 /**
26 * <p>A container for DATA frames metadata and content bytes.</p>
27 * <p>Specialized subclasses (like {@link StringDataInfo}) may be used by applications
28 * to send specific types of content.</p>
29 * <p>Applications may send multiple instances of {@link DataInfo}, usually of the same
30 * type, via {@link Stream#data(DataInfo)}. The last instance must have the
31 * {@link #isClose() close flag} set, so that the client knows that no more content is
32 * expected.</p>
33 * <p>Receivers of {@link DataInfo} via {@link StreamFrameListener#onData(Stream, DataInfo)}
34 * have two different APIs to read the data content bytes: a {@link #readInto(ByteBuffer) read}
35 * API that does not interact with flow control, and a {@link #consumeInto(ByteBuffer) drain}
36 * API that interacts with flow control.</p>
37 * <p>Flow control is defined so that when the sender wants to sends a number of bytes larger
38 * than the {@link Settings.ID#INITIAL_WINDOW_SIZE} value, it will stop sending as soon as it
39 * has sent a number of bytes equal to the window size. The receiver has to <em>consume</em>
40 * the data bytes that it received in order to tell the sender to send more bytes.</p>
41 * <p>Consuming the data bytes can be done only via {@link #consumeInto(ByteBuffer)} or by a combination
42 * of {@link #readInto(ByteBuffer)} and {@link #consume(int)} (possibly at different times).</p>
43 */
44 public abstract class DataInfo
45 {
46 /**
47 * <p>Flag that indicates that this {@link DataInfo} is the last frame in the stream.</p>
48 *
49 * @see #isClose()
50 * @see #getFlags()
51 */
52 public final static byte FLAG_CLOSE = 1;
53 /**
54 * <p>Flag that indicates that this {@link DataInfo}'s data is compressed.</p>
55 *
56 * @see #isCompress()
57 * @see #getFlags()
58 */
59 public final static byte FLAG_COMPRESS = 2;
60
61 private final AtomicInteger consumed = new AtomicInteger();
62 private boolean close;
63 private boolean compress;
64
65 /**
66 * <p>Creates a new {@link DataInfo} with the given close flag and no compression flag.</p>
67 *
68 * @param close the value of the close flag
69 */
70 public DataInfo(boolean close)
71 {
72 setClose(close);
73 }
74
75 /**
76 * <p>Creates a new {@link DataInfo} with the given close flag and given compression flag.</p>
77 *
78 * @param close the close flag
79 * @param compress the compress flag
80 */
81 public DataInfo(boolean close, boolean compress)
82 {
83 setClose(close);
84 setCompress(compress);
85 }
86
87 /**
88 * @return the value of the compress flag
89 * @see #setCompress(boolean)
90 */
91 public boolean isCompress()
92 {
93 return compress;
94 }
95
96 /**
97 * @param compress the value of the compress flag
98 * @see #isCompress()
99 */
100 public void setCompress(boolean compress)
101 {
102 this.compress = compress;
103 }
104
105 /**
106 * @return the value of the close flag
107 * @see #setClose(boolean)
108 */
109 public boolean isClose()
110 {
111 return close;
112 }
113
114 /**
115 * @param close the value of the close flag
116 * @see #isClose()
117 */
118 public void setClose(boolean close)
119 {
120 this.close = close;
121 }
122
123 /**
124 * @return the close and compress flags as integer
125 * @see #FLAG_CLOSE
126 * @see #FLAG_COMPRESS
127 */
128 public byte getFlags()
129 {
130 byte flags = isClose() ? FLAG_CLOSE : 0;
131 flags |= isCompress() ? FLAG_COMPRESS : 0;
132 return flags;
133 }
134
135 /**
136 * @return the total number of content bytes
137 * @see #available()
138 */
139 public abstract int length();
140
141 /**
142 * <p>Returns the available content bytes that can be read via {@link #readInto(ByteBuffer)}.</p>
143 * <p>Each invocation to {@link #readInto(ByteBuffer)} modifies the value returned by this method,
144 * until no more content bytes are available.</p>
145 *
146 * @return the available content bytes
147 * @see #readInto(ByteBuffer)
148 */
149 public abstract int available();
150
151 /**
152 * <p>Copies the content bytes of this {@link DataInfo} into the given {@link ByteBuffer}.</p>
153 * <p>If the given {@link ByteBuffer} cannot contain the whole content of this {@link DataInfo}
154 * then after the read {@link #available()} will return a positive value, and further content
155 * may be retrieved by invoking again this method with a new output buffer.</p>
156 *
157 * @param output the {@link ByteBuffer} to copy to bytes into
158 * @return the number of bytes copied
159 * @see #available()
160 * @see #consumeInto(ByteBuffer)
161 */
162 public abstract int readInto(ByteBuffer output);
163
164 /**
165 * <p>Reads and consumes the content bytes of this {@link DataInfo} into the given {@link ByteBuffer}.</p>
166 *
167 * @param output the {@link ByteBuffer} to copy the bytes into
168 * @return the number of bytes copied
169 * @see #consume(int)
170 */
171 public int consumeInto(ByteBuffer output)
172 {
173 int read = readInto(output);
174 consume(read);
175 return read;
176 }
177
178 /**
179 * <p>Consumes the given number of bytes from this {@link DataInfo}.</p>
180 *
181 * @param delta the number of bytes consumed
182 */
183 public void consume(int delta)
184 {
185 if (delta < 0)
186 throw new IllegalArgumentException();
187 int read = length() - available();
188 int newConsumed = consumed() + delta;
189 // if (newConsumed > read)
190 // throw new IllegalStateException("Consuming without reading: consumed " + newConsumed + " but only read " + read);
191 consumed.addAndGet(delta);
192 }
193
194 /**
195 * @return the number of bytes consumed
196 */
197 public int consumed()
198 {
199 return consumed.get();
200 }
201
202 /**
203 *
204 * @param charset the charset used to convert the bytes
205 * @param consume whether to consume the content
206 * @return a String with the content of this {@link DataInfo}
207 */
208 public String asString(String charset, boolean consume)
209 {
210 ByteBuffer buffer = asByteBuffer(consume);
211 return Charset.forName(charset).decode(buffer).toString();
212 }
213
214 /**
215 * @return a byte array with the content of this {@link DataInfo}
216 * @param consume whether to consume the content
217 */
218 public byte[] asBytes(boolean consume)
219 {
220 ByteBuffer buffer = asByteBuffer(consume);
221 byte[] result = new byte[buffer.remaining()];
222 buffer.get(result);
223 return result;
224 }
225
226 /**
227 * @return a {@link ByteBuffer} with the content of this {@link DataInfo}
228 * @param consume whether to consume the content
229 */
230 public ByteBuffer asByteBuffer(boolean consume)
231 {
232 ByteBuffer buffer = allocate(available());
233 if (consume)
234 consumeInto(buffer);
235 else
236 readInto(buffer);
237 buffer.flip();
238 return buffer;
239 }
240
241 protected ByteBuffer allocate(int size)
242 {
243 return ByteBuffer.allocate(size);
244 }
245
246 @Override
247 public String toString()
248 {
249 return String.format("DATA @%x available=%d consumed=%d close=%b compress=%b", hashCode(), available(), consumed(), isClose(), isCompress());
250 }
251 }