1 //
2 // ========================================================================
3 // Copyright (c) 1995-2014 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.client;
20
21 import java.io.Closeable;
22 import java.nio.ByteBuffer;
23 import java.util.Collections;
24 import java.util.Iterator;
25
26 import org.eclipse.jetty.client.api.ContentProvider;
27 import org.eclipse.jetty.client.util.DeferredContentProvider;
28 import org.eclipse.jetty.util.BufferUtil;
29 import org.eclipse.jetty.util.Callback;
30 import org.eclipse.jetty.util.log.Log;
31 import org.eclipse.jetty.util.log.Logger;
32
33 /**
34 * {@link HttpContent} is a stateful, linear representation of the request content provided
35 * by a {@link ContentProvider} that can be traversed one-way to obtain content buffers to
36 * send to a HTTP server.
37 * <p />
38 * {@link HttpContent} offers the notion of a one-way cursor to traverse the content.
39 * The cursor starts in a virtual "before" position and can be advanced using {@link #advance()}
40 * until it reaches a virtual "after" position where the content is fully consumed.
41 * <pre>
42 * +---+ +---+ +---+ +---+ +---+
43 * | | | | | | | | | |
44 * +---+ +---+ +---+ +---+ +---+
45 * ^ ^ ^ ^
46 * | | --> advance() | |
47 * | | last |
48 * | | |
49 * before | after
50 * |
51 * current
52 * </pre>
53 * At each valid (non-before and non-after) cursor position, {@link HttpContent} provides the following state:
54 * <ul>
55 * <li>the buffer containing the content to send, via {@link #getByteBuffer()}</li>
56 * <li>a copy of the content buffer that can be used for notifications, via {@link #getContent()}</li>
57 * <li>whether the buffer to write is the last one, via {@link #isLast()}</li>
58 * </ul>
59 * {@link HttpContent} may not have content, if the related {@link ContentProvider} is {@code null}, and this
60 * is reflected by {@link #hasContent()}.
61 * <p />
62 * {@link HttpContent} may have {@link DeferredContentProvider deferred content}, in which case {@link #advance()}
63 * moves the cursor to a position that provides {@code null} {@link #getByteBuffer() buffer} and
64 * {@link #getContent() content}. When the deferred content is available, a further call to {@link #advance()}
65 * will move the cursor to a position that provides non {@code null} buffer and content.
66 */
67 public class HttpContent implements Callback, Closeable
68 {
69 private static final Logger LOG = Log.getLogger(HttpContent.class);
70 private static final ByteBuffer AFTER = ByteBuffer.allocate(0);
71
72 private final ContentProvider provider;
73 private final Iterator<ByteBuffer> iterator;
74 private ByteBuffer buffer;
75 private volatile ByteBuffer content;
76
77 public HttpContent(ContentProvider provider)
78 {
79 this.provider = provider;
80 this.iterator = provider == null ? Collections.<ByteBuffer>emptyIterator() : provider.iterator();
81 }
82
83 /**
84 * @return whether there is any content at all
85 */
86 public boolean hasContent()
87 {
88 return provider != null;
89 }
90
91 /**
92 * @return whether the cursor points to the last content
93 */
94 public boolean isLast()
95 {
96 return !iterator.hasNext();
97 }
98
99 /**
100 * @return the {@link ByteBuffer} containing the content at the cursor's position
101 */
102 public ByteBuffer getByteBuffer()
103 {
104 return buffer;
105 }
106
107 /**
108 * @return a {@link ByteBuffer#slice()} of {@link #getByteBuffer()} at the cursor's position
109 */
110 public ByteBuffer getContent()
111 {
112 return content;
113 }
114
115 /**
116 * Advances the cursor to the next block of content.
117 * <p />
118 * The next block of content may be valid (which yields a non-null buffer
119 * returned by {@link #getByteBuffer()}), but may also be deferred
120 * (which yields a null buffer returned by {@link #getByteBuffer()}).
121 * <p />
122 * If the block of content pointed by the new cursor position is valid, this method returns true.
123 *
124 * @return true if there is content at the new cursor's position, false otherwise.
125 */
126 public boolean advance()
127 {
128 if (isLast())
129 {
130 if (content != AFTER)
131 {
132 content = buffer = AFTER;
133 LOG.debug("Advanced content past last chunk");
134 }
135 return false;
136 }
137 else
138 {
139 ByteBuffer buffer = this.buffer = iterator.next();
140 if (LOG.isDebugEnabled())
141 LOG.debug("Advanced content to {} chunk {}", isLast() ? "last" : "next", buffer);
142 content = buffer == null ? null : buffer.slice();
143 return buffer != null;
144 }
145 }
146
147 /**
148 * @return whether the cursor has been advanced past the {@link #isLast() last} position.
149 */
150 public boolean isConsumed()
151 {
152 return content == AFTER;
153 }
154
155 @Override
156 public void succeeded()
157 {
158 if (iterator instanceof Callback)
159 ((Callback)iterator).succeeded();
160 }
161
162 @Override
163 public void failed(Throwable x)
164 {
165 if (iterator instanceof Callback)
166 ((Callback)iterator).failed(x);
167 }
168
169 @Override
170 public void close()
171 {
172 try
173 {
174 if (iterator instanceof Closeable)
175 ((Closeable)iterator).close();
176 }
177 catch (Exception x)
178 {
179 LOG.ignore(x);
180 }
181 }
182
183 @Override
184 public String toString()
185 {
186 return String.format("%s@%x - has=%b,last=%b,consumed=%b,buffer=%s",
187 getClass().getSimpleName(),
188 hashCode(),
189 hasContent(),
190 isLast(),
191 isConsumed(),
192 BufferUtil.toDetailString(getContent()));
193 }
194 }