SocketInputStream.java revision 12745:f068a4ffddd2
1/* 2 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package java.net; 27 28import java.io.FileDescriptor; 29import java.io.FileInputStream; 30import java.io.IOException; 31import java.nio.channels.FileChannel; 32 33import 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 */ 43class 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} method of {@code SocketInputStream} 71 * returns {@code null} 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 // wrap native call to allow instrumentation 100 /** 101 * Reads into an array of bytes at the specified offset using 102 * the received socket primitive. 103 * @param fd the FileDescriptor 104 * @param b the buffer into which the data is read 105 * @param off the start offset of the data 106 * @param len the maximum number of bytes read 107 * @param timeout the read timeout in ms 108 * @return the actual number of bytes read, -1 is 109 * returned when the end of the stream is reached. 110 * @exception IOException If an I/O error has occurred. 111 */ 112 private int socketRead(FileDescriptor fd, 113 byte b[], int off, int len, 114 int timeout) 115 throws IOException { 116 return socketRead0(fd, b, off, len, timeout); 117 } 118 119 /** 120 * Reads into a byte array data from the socket. 121 * @param b the buffer into which the data is read 122 * @return the actual number of bytes read, -1 is 123 * returned when the end of the stream is reached. 124 * @exception IOException If an I/O error has occurred. 125 */ 126 public int read(byte b[]) throws IOException { 127 return read(b, 0, b.length); 128 } 129 130 /** 131 * Reads into a byte array <i>b</i> at offset <i>off</i>, 132 * <i>length</i> bytes of data. 133 * @param b the buffer into which the data is read 134 * @param off the start offset of the data 135 * @param length the maximum number of bytes read 136 * @return the actual number of bytes read, -1 is 137 * returned when the end of the stream is reached. 138 * @exception IOException If an I/O error has occurred. 139 */ 140 public int read(byte b[], int off, int length) throws IOException { 141 return read(b, off, length, impl.getTimeout()); 142 } 143 144 int read(byte b[], int off, int length, int timeout) throws IOException { 145 int n; 146 147 // EOF already encountered 148 if (eof) { 149 return -1; 150 } 151 152 // connection reset 153 if (impl.isConnectionReset()) { 154 throw new SocketException("Connection reset"); 155 } 156 157 // bounds check 158 if (length <= 0 || off < 0 || off + length > b.length) { 159 if (length == 0) { 160 return 0; 161 } 162 throw new ArrayIndexOutOfBoundsException(); 163 } 164 165 boolean gotReset = false; 166 167 // acquire file descriptor and do the read 168 FileDescriptor fd = impl.acquireFD(); 169 try { 170 n = socketRead(fd, b, off, length, timeout); 171 if (n > 0) { 172 return n; 173 } 174 } catch (ConnectionResetException rstExc) { 175 gotReset = true; 176 } finally { 177 impl.releaseFD(); 178 } 179 180 /* 181 * We receive a "connection reset" but there may be bytes still 182 * buffered on the socket 183 */ 184 if (gotReset) { 185 impl.setConnectionResetPending(); 186 impl.acquireFD(); 187 try { 188 n = socketRead(fd, b, off, length, timeout); 189 if (n > 0) { 190 return n; 191 } 192 } catch (ConnectionResetException rstExc) { 193 } finally { 194 impl.releaseFD(); 195 } 196 } 197 198 /* 199 * If we get here we are at EOF, the socket has been closed, 200 * or the connection has been reset. 201 */ 202 if (impl.isClosedOrPending()) { 203 throw new SocketException("Socket closed"); 204 } 205 if (impl.isConnectionResetPending()) { 206 impl.setConnectionReset(); 207 } 208 if (impl.isConnectionReset()) { 209 throw new SocketException("Connection reset"); 210 } 211 eof = true; 212 return -1; 213 } 214 215 /** 216 * Reads a single byte from the socket. 217 */ 218 public int read() throws IOException { 219 if (eof) { 220 return -1; 221 } 222 temp = new byte[1]; 223 int n = read(temp, 0, 1); 224 if (n <= 0) { 225 return -1; 226 } 227 return temp[0] & 0xff; 228 } 229 230 /** 231 * Skips n bytes of input. 232 * @param numbytes the number of bytes to skip 233 * @return the actual number of bytes skipped. 234 * @exception IOException If an I/O error has occurred. 235 */ 236 public long skip(long numbytes) throws IOException { 237 if (numbytes <= 0) { 238 return 0; 239 } 240 long n = numbytes; 241 int buflen = (int) Math.min(1024, n); 242 byte data[] = new byte[buflen]; 243 while (n > 0) { 244 int r = read(data, 0, (int) Math.min((long) buflen, n)); 245 if (r < 0) { 246 break; 247 } 248 n -= r; 249 } 250 return numbytes - n; 251 } 252 253 /** 254 * Returns the number of bytes that can be read without blocking. 255 * @return the number of immediately available bytes 256 */ 257 public int available() throws IOException { 258 return impl.available(); 259 } 260 261 /** 262 * Closes the stream. 263 */ 264 private boolean closing = false; 265 public void close() throws IOException { 266 // Prevent recursion. See BugId 4484411 267 if (closing) 268 return; 269 closing = true; 270 if (socket != null) { 271 if (!socket.isClosed()) 272 socket.close(); 273 } else 274 impl.close(); 275 closing = false; 276 } 277 278 void setEOF(boolean eof) { 279 this.eof = eof; 280 } 281 282 /** 283 * Overrides finalize, the fd is closed by the Socket. 284 */ 285 protected void finalize() {} 286 287 /** 288 * Perform class load-time initializations. 289 */ 290 private static native void init(); 291} 292