1 /*
2 * Copyright 1995-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.net;
27
28 import java.io.FileDescriptor;
29 import java.io.FileInputStream;
30 import java.io.IOException;
31 import java.nio.channels.FileChannel;
32
33 import sun.net.ConnectionResetException;
34
35 /**
36 * This stream extends FileInputStream to implement a
37 * SocketInputStream. Note that this class should <b>NOT</b> be
38 * public.
39 *
40 * @author Jonathan Payne
41 * @author Arthur van Hoff
42 */
43 class SocketInputStream extends FileInputStream
44 {
45 static {
46 init();
47 }
48
49 private boolean eof;
50 private AbstractPlainSocketImpl impl = null;
51 private byte temp[];
52 private Socket socket = null;
53
54 /**
55 * Creates a new SocketInputStream. Can only be called
56 * by a Socket. This method needs to hang on to the owner Socket so
57 * that the fd will not be closed.
58 * @param impl the implemented socket input stream
59 */
60 SocketInputStream(AbstractPlainSocketImpl impl) throws IOException {
61 super(impl.getFileDescriptor());
62 this.impl = impl;
63 socket = impl.getSocket();
64 }
65
66 /**
67 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
68 * object associated with this file input stream.</p>
69 *
70 * The <code>getChannel</code> method of <code>SocketInputStream</code>
71 * returns <code>null</code> since it is a socket based stream.</p>
72 *
73 * @return the file channel associated with this file input stream
74 *
75 * @since 1.4
76 * @spec JSR-51
77 */
78 public final FileChannel getChannel() {
79 return null;
80 }
81
82 /**
83 * Reads into an array of bytes at the specified offset using
84 * the received socket primitive.
85 * @param fd the FileDescriptor
86 * @param b the buffer into which the data is read
87 * @param off the start offset of the data
88 * @param len the maximum number of bytes read
89 * @param timeout the read timeout in ms
90 * @return the actual number of bytes read, -1 is
91 * returned when the end of the stream is reached.
92 * @exception IOException If an I/O error has occurred.
93 */
94 private native int socketRead0(FileDescriptor fd,
95 byte b[], int off, int len,
96 int timeout)
97 throws IOException;
98
99 /**
100 * Reads into a byte array data from the socket.
101 * @param b the buffer into which the data is read
102 * @return the actual number of bytes read, -1 is
103 * returned when the end of the stream is reached.
104 * @exception IOException If an I/O error has occurred.
105 */
106 public int read(byte b[]) throws IOException {
107 return read(b, 0, b.length);
108 }
109
110 /**
111 * Reads into a byte array <i>b</i> at offset <i>off</i>,
112 * <i>length</i> bytes of data.
113 * @param b the buffer into which the data is read
114 * @param off the start offset of the data
115 * @param len the maximum number of bytes read
116 * @return the actual number of bytes read, -1 is
117 * returned when the end of the stream is reached.
118 * @exception IOException If an I/O error has occurred.
119 */
120 public int read(byte b[], int off, int length) throws IOException {
121 int n;
122
123 // EOF already encountered
124 if (eof) {
125 return -1;
126 }
127
128 // connection reset
129 if (impl.isConnectionReset()) {
130 throw new SocketException("Connection reset");
131 }
132
133 // bounds check
134 if (length <= 0 || off < 0 || off + length > b.length) {
135 if (length == 0) {
136 return 0;
137 }
138 throw new ArrayIndexOutOfBoundsException();
139 }
140
141 boolean gotReset = false;
142
143 // acquire file descriptor and do the read
144 FileDescriptor fd = impl.acquireFD();
145 try {
146 n = socketRead0(fd, b, off, length, impl.getTimeout());
147 if (n > 0) {
148 return n;
149 }
150 } catch (ConnectionResetException rstExc) {
151 gotReset = true;
152 } finally {
153 impl.releaseFD();
154 }
155
156 /*
157 * We receive a "connection reset" but there may be bytes still
158 * buffered on the socket
159 */
160 if (gotReset) {
161 impl.setConnectionResetPending();
162 impl.acquireFD();
163 try {
164 n = socketRead0(fd, b, off, length, impl.getTimeout());
165 if (n > 0) {
166 return n;
167 }
168 } catch (ConnectionResetException rstExc) {
169 } finally {
170 impl.releaseFD();
171 }
172 }
173
174 /*
175 * If we get here we are at EOF, the socket has been closed,
176 * or the connection has been reset.
177 */
178 if (impl.isClosedOrPending()) {
179 throw new SocketException("Socket closed");
180 }
181 if (impl.isConnectionResetPending()) {
182 impl.setConnectionReset();
183 }
184 if (impl.isConnectionReset()) {
185 throw new SocketException("Connection reset");
186 }
187 eof = true;
188 return -1;
189 }
190
191 /**
192 * Reads a single byte from the socket.
193 */
194 public int read() throws IOException {
195 if (eof) {
196 return -1;
197 }
198 temp = new byte[1];
199 int n = read(temp, 0, 1);
200 if (n <= 0) {
201 return -1;
202 }
203 return temp[0] & 0xff;
204 }
205
206 /**
207 * Skips n bytes of input.
208 * @param n the number of bytes to skip
209 * @return the actual number of bytes skipped.
210 * @exception IOException If an I/O error has occurred.
211 */
212 public long skip(long numbytes) throws IOException {
213 if (numbytes <= 0) {
214 return 0;
215 }
216 long n = numbytes;
217 int buflen = (int) Math.min(1024, n);
218 byte data[] = new byte[buflen];
219 while (n > 0) {
220 int r = read(data, 0, (int) Math.min((long) buflen, n));
221 if (r < 0) {
222 break;
223 }
224 n -= r;
225 }
226 return numbytes - n;
227 }
228
229 /**
230 * Returns the number of bytes that can be read without blocking.
231 * @return the number of immediately available bytes
232 */
233 public int available() throws IOException {
234 return impl.available();
235 }
236
237 /**
238 * Closes the stream.
239 */
240 private boolean closing = false;
241 public void close() throws IOException {
242 // Prevent recursion. See BugId 4484411
243 if (closing)
244 return;
245 closing = true;
246 if (socket != null) {
247 if (!socket.isClosed())
248 socket.close();
249 } else
250 impl.close();
251 closing = false;
252 }
253
254 void setEOF(boolean eof) {
255 this.eof = eof;
256 }
257
258 /**
259 * Overrides finalize, the fd is closed by the Socket.
260 */
261 protected void finalize() {}
262
263 /**
264 * Perform class load-time initializations.
265 */
266 private native static void init();
267 }
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