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| 1 | /* | ||
| 2 | * Copyright (c) 1994, 2011, 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 | |||
| 26 | package java.io; | ||
| 27 | |||
| 28 | import java.nio.channels.FileChannel; | ||
| 29 | import sun.nio.ch.FileChannelImpl; | ||
| 30 | |||
| 31 | |||
| 32 | /** | ||
| 33 | * A <code>FileInputStream</code> obtains input bytes | ||
| 34 | * from a file in a file system. What files | ||
| 35 | * are available depends on the host environment. | ||
| 36 | * | ||
| 37 | * <p><code>FileInputStream</code> is meant for reading streams of raw bytes | ||
| 38 | * such as image data. For reading streams of characters, consider using | ||
| 39 | * <code>FileReader</code>. | ||
| 40 | * | ||
| 41 | * @author Arthur van Hoff | ||
| 42 | * @see java.io.File | ||
| 43 | * @see java.io.FileDescriptor | ||
| 44 | * @see java.io.FileOutputStream | ||
| 45 | * @see java.nio.file.Files#newInputStream | ||
| 46 | * @since JDK1.0 | ||
| 47 | */ | ||
| 48 | public | ||
| 49 | class FileInputStream extends InputStream | ||
| 50 | { | ||
| 51 | /* File Descriptor - handle to the open file */ | ||
| 52 | private final FileDescriptor fd; | ||
| 53 | |||
| 54 | private FileChannel channel = null; | ||
| 55 | |||
| 56 | private final Object closeLock = new Object(); | ||
| 57 | private volatile boolean closed = false; | ||
| 58 | |||
| 59 | private static final ThreadLocal<Boolean> runningFinalize = | ||
| 60 | new ThreadLocal<>(); | ||
| 61 | |||
| 62 | private static boolean isRunningFinalize() { | ||
| 63 | Boolean val; | ||
| 64 | if ((val = runningFinalize.get()) != null) | ||
| 65 | return val.booleanValue(); | ||
| 66 | return false; | ||
| 67 | } | ||
| 68 | |||
| 69 | /** | ||
| 70 | * Creates a <code>FileInputStream</code> by | ||
| 71 | * opening a connection to an actual file, | ||
| 72 | * the file named by the path name <code>name</code> | ||
| 73 | * in the file system. A new <code>FileDescriptor</code> | ||
| 74 | * object is created to represent this file | ||
| 75 | * connection. | ||
| 76 | * <p> | ||
| 77 | * First, if there is a security | ||
| 78 | * manager, its <code>checkRead</code> method | ||
| 79 | * is called with the <code>name</code> argument | ||
| 80 | * as its argument. | ||
| 81 | * <p> | ||
| 82 | * If the named file does not exist, is a directory rather than a regular | ||
| 83 | * file, or for some other reason cannot be opened for reading then a | ||
| 84 | * <code>FileNotFoundException</code> is thrown. | ||
| 85 | * | ||
| 86 | * @param name the system-dependent file name. | ||
| 87 | * @exception FileNotFoundException if the file does not exist, | ||
| 88 | * is a directory rather than a regular file, | ||
| 89 | * or for some other reason cannot be opened for | ||
| 90 | * reading. | ||
| 91 | * @exception SecurityException if a security manager exists and its | ||
| 92 | * <code>checkRead</code> method denies read access | ||
| 93 | * to the file. | ||
| 94 | * @see java.lang.SecurityManager#checkRead(java.lang.String) | ||
| 95 | */ | ||
| 96 | public FileInputStream(String name) throws FileNotFoundException { | ||
| 97 | this(name != null ? new File(name) : null); | ||
| 98 | } | ||
| 99 | |||
| 100 | /** | ||
| 101 | * Creates a <code>FileInputStream</code> by | ||
| 102 | * opening a connection to an actual file, | ||
| 103 | * the file named by the <code>File</code> | ||
| 104 | * object <code>file</code> in the file system. | ||
| 105 | * A new <code>FileDescriptor</code> object | ||
| 106 | * is created to represent this file connection. | ||
| 107 | * <p> | ||
| 108 | * First, if there is a security manager, | ||
| 109 | * its <code>checkRead</code> method is called | ||
| 110 | * with the path represented by the <code>file</code> | ||
| 111 | * argument as its argument. | ||
| 112 | * <p> | ||
| 113 | * If the named file does not exist, is a directory rather than a regular | ||
| 114 | * file, or for some other reason cannot be opened for reading then a | ||
| 115 | * <code>FileNotFoundException</code> is thrown. | ||
| 116 | * | ||
| 117 | * @param file the file to be opened for reading. | ||
| 118 | * @exception FileNotFoundException if the file does not exist, | ||
| 119 | * is a directory rather than a regular file, | ||
| 120 | * or for some other reason cannot be opened for | ||
| 121 | * reading. | ||
| 122 | * @exception SecurityException if a security manager exists and its | ||
| 123 | * <code>checkRead</code> method denies read access to the file. | ||
| 124 | * @see java.io.File#getPath() | ||
| 125 | * @see java.lang.SecurityManager#checkRead(java.lang.String) | ||
| 126 | */ | ||
| 127 | public FileInputStream(File file) throws FileNotFoundException { | ||
| 128 | String name = (file != null ? file.getPath() : null); | ||
| 129 | SecurityManager security = System.getSecurityManager(); | ||
| 130 | if (security != null) { | ||
| 131 | security.checkRead(name); | ||
| 132 | } | ||
| 133 | if (name == null) { | ||
| 134 | throw new NullPointerException(); | ||
| 135 | } | ||
| 136 | fd = new FileDescriptor(); | ||
| 137 | fd.incrementAndGetUseCount(); | ||
| 138 | open(name); | ||
| 139 | } | ||
| 140 | |||
| 141 | /** | ||
| 142 | * Creates a <code>FileInputStream</code> by using the file descriptor | ||
| 143 | * <code>fdObj</code>, which represents an existing connection to an | ||
| 144 | * actual file in the file system. | ||
| 145 | * <p> | ||
| 146 | * If there is a security manager, its <code>checkRead</code> method is | ||
| 147 | * called with the file descriptor <code>fdObj</code> as its argument to | ||
| 148 | * see if it's ok to read the file descriptor. If read access is denied | ||
| 149 | * to the file descriptor a <code>SecurityException</code> is thrown. | ||
| 150 | * <p> | ||
| 151 | * If <code>fdObj</code> is null then a <code>NullPointerException</code> | ||
| 152 | * is thrown. | ||
| 153 | * <p> | ||
| 154 | * This constructor does not throw an exception if <code>fdObj</code> | ||
| 155 | * is {@link java.io.FileDescriptor#valid() invalid}. | ||
| 156 | * However, if the methods are invoked on the resulting stream to attempt | ||
| 157 | * I/O on the stream, an <code>IOException</code> is thrown. | ||
| 158 | * | ||
| 159 | * @param fdObj the file descriptor to be opened for reading. | ||
| 160 | * @throws SecurityException if a security manager exists and its | ||
| 161 | * <code>checkRead</code> method denies read access to the | ||
| 162 | * file descriptor. | ||
| 163 | * @see SecurityManager#checkRead(java.io.FileDescriptor) | ||
| 164 | */ | ||
| 165 | public FileInputStream(FileDescriptor fdObj) { | ||
| 166 | SecurityManager security = System.getSecurityManager(); | ||
| 167 | if (fdObj == null) { | ||
| 168 | throw new NullPointerException(); | ||
| 169 | } | ||
| 170 | if (security != null) { | ||
| 171 | security.checkRead(fdObj); | ||
| 172 | } | ||
| 173 | fd = fdObj; | ||
| 174 | |||
| 175 | /* | ||
| 176 | * FileDescriptor is being shared by streams. | ||
| 177 | * Ensure that it's GC'ed only when all the streams/channels are done | ||
| 178 | * using it. | ||
| 179 | */ | ||
| 180 | fd.incrementAndGetUseCount(); | ||
| 181 | } | ||
| 182 | |||
| 183 | /** | ||
| 184 | * Opens the specified file for reading. | ||
| 185 | * @param name the name of the file | ||
| 186 | */ | ||
| 187 | private native void open(String name) throws FileNotFoundException; | ||
| 188 | |||
| 189 | /** | ||
| 190 | * Reads a byte of data from this input stream. This method blocks | ||
| 191 | * if no input is yet available. | ||
| 192 | * | ||
| 193 | * @return the next byte of data, or <code>-1</code> if the end of the | ||
| 194 | * file is reached. | ||
| 195 | * @exception IOException if an I/O error occurs. | ||
| 196 | */ | ||
| 197 | public native int read() throws IOException; | ||
| 198 | |||
| 199 | /** | ||
| 200 | * Reads a subarray as a sequence of bytes. | ||
| 201 | * @param b the data to be written | ||
| 202 | * @param off the start offset in the data | ||
| 203 | * @param len the number of bytes that are written | ||
| 204 | * @exception IOException If an I/O error has occurred. | ||
| 205 | */ | ||
| 206 | private native int readBytes(byte b[], int off, int len) throws IOException; | ||
| 207 | |||
| 208 | /** | ||
| 209 | * Reads up to <code>b.length</code> bytes of data from this input | ||
| 210 | * stream into an array of bytes. This method blocks until some input | ||
| 211 | * is available. | ||
| 212 | * | ||
| 213 | * @param b the buffer into which the data is read. | ||
| 214 | * @return the total number of bytes read into the buffer, or | ||
| 215 | * <code>-1</code> if there is no more data because the end of | ||
| 216 | * the file has been reached. | ||
| 217 | * @exception IOException if an I/O error occurs. | ||
| 218 | */ | ||
| 219 | public int read(byte b[]) throws IOException { | ||
| 220 | return readBytes(b, 0, b.length); | ||
| 221 | } | ||
| 222 | |||
| 223 | /** | ||
| 224 | * Reads up to <code>len</code> bytes of data from this input stream | ||
| 225 | * into an array of bytes. If <code>len</code> is not zero, the method | ||
| 226 | * blocks until some input is available; otherwise, no | ||
| 227 | * bytes are read and <code>0</code> is returned. | ||
| 228 | * | ||
| 229 | * @param b the buffer into which the data is read. | ||
| 230 | * @param off the start offset in the destination array <code>b</code> | ||
| 231 | * @param len the maximum number of bytes read. | ||
| 232 | * @return the total number of bytes read into the buffer, or | ||
| 233 | * <code>-1</code> if there is no more data because the end of | ||
| 234 | * the file has been reached. | ||
| 235 | * @exception NullPointerException If <code>b</code> is <code>null</code>. | ||
| 236 | * @exception IndexOutOfBoundsException If <code>off</code> is negative, | ||
| 237 | * <code>len</code> is negative, or <code>len</code> is greater than | ||
| 238 | * <code>b.length - off</code> | ||
| 239 | * @exception IOException if an I/O error occurs. | ||
| 240 | */ | ||
| 241 | public int read(byte b[], int off, int len) throws IOException { | ||
| 242 | return readBytes(b, off, len); | ||
| 243 | } | ||
| 244 | |||
| 245 | /** | ||
| 246 | * Skips over and discards <code>n</code> bytes of data from the | ||
| 247 | * input stream. | ||
| 248 | * | ||
| 249 | * <p>The <code>skip</code> method may, for a variety of | ||
| 250 | * reasons, end up skipping over some smaller number of bytes, | ||
| 251 | * possibly <code>0</code>. If <code>n</code> is negative, an | ||
| 252 | * <code>IOException</code> is thrown, even though the <code>skip</code> | ||
| 253 | * method of the {@link InputStream} superclass does nothing in this case. | ||
| 254 | * The actual number of bytes skipped is returned. | ||
| 255 | * | ||
| 256 | * <p>This method may skip more bytes than are remaining in the backing | ||
| 257 | * file. This produces no exception and the number of bytes skipped | ||
| 258 | * may include some number of bytes that were beyond the EOF of the | ||
| 259 | * backing file. Attempting to read from the stream after skipping past | ||
| 260 | * the end will result in -1 indicating the end of the file. | ||
| 261 | * | ||
| 262 | * @param n the number of bytes to be skipped. | ||
| 263 | * @return the actual number of bytes skipped. | ||
| 264 | * @exception IOException if n is negative, if the stream does not | ||
| 265 | * support seek, or if an I/O error occurs. | ||
| 266 | */ | ||
| 267 | public native long skip(long n) throws IOException; | ||
| 268 | |||
| 269 | /** | ||
| 270 | * Returns an estimate of the number of remaining bytes that can be read (or | ||
| 271 | * skipped over) from this input stream without blocking by the next | ||
| 272 | * invocation of a method for this input stream. The next invocation might be | ||
| 273 | * the same thread or another thread. A single read or skip of this | ||
| 274 | * many bytes will not block, but may read or skip fewer bytes. | ||
| 275 | * | ||
| 276 | * <p> In some cases, a non-blocking read (or skip) may appear to be | ||
| 277 | * blocked when it is merely slow, for example when reading large | ||
| 278 | * files over slow networks. | ||
| 279 | * | ||
| 280 | * @return an estimate of the number of remaining bytes that can be read | ||
| 281 | * (or skipped over) from this input stream without blocking. | ||
| 282 | * @exception IOException if this file input stream has been closed by calling | ||
| 283 | * {@code close} or an I/O error occurs. | ||
| 284 | */ | ||
| 285 | public native int available() throws IOException; | ||
| 286 | |||
| 287 | /** | ||
| 288 | * Closes this file input stream and releases any system resources | ||
| 289 | * associated with the stream. | ||
| 290 | * | ||
| 291 | * <p> If this stream has an associated channel then the channel is closed | ||
| 292 | * as well. | ||
| 293 | * | ||
| 294 | * @exception IOException if an I/O error occurs. | ||
| 295 | * | ||
| 296 | * @revised 1.4 | ||
| 297 | * @spec JSR-51 | ||
| 298 | */ | ||
| 299 | public void close() throws IOException { | ||
| 300 | synchronized (closeLock) { | ||
| 301 | if (closed) { | ||
| 302 | return; | ||
| 303 | } | ||
| 304 | closed = true; | ||
| 305 | } | ||
| 306 | if (channel != null) { | ||
| 307 | /* | ||
| 308 | * Decrement the FD use count associated with the channel | ||
| 309 | * The use count is incremented whenever a new channel | ||
| 310 | * is obtained from this stream. | ||
| 311 | */ | ||
| 312 | fd.decrementAndGetUseCount(); | ||
| 313 | channel.close(); | ||
| 314 | } | ||
| 315 | |||
| 316 | /* | ||
| 317 | * Decrement the FD use count associated with this stream | ||
| 318 | */ | ||
| 319 | int useCount = fd.decrementAndGetUseCount(); | ||
| 320 | |||
| 321 | /* | ||
| 322 | * If FileDescriptor is still in use by another stream, the finalizer | ||
| 323 | * will not close it. | ||
| 324 | */ | ||
| 325 | if ((useCount <= 0) || !isRunningFinalize()) { | ||
| 326 | close0(); | ||
| 327 | } | ||
| 328 | } | ||
| 329 | |||
| 330 | /** | ||
| 331 | * Returns the <code>FileDescriptor</code> | ||
| 332 | * object that represents the connection to | ||
| 333 | * the actual file in the file system being | ||
| 334 | * used by this <code>FileInputStream</code>. | ||
| 335 | * | ||
| 336 | * @return the file descriptor object associated with this stream. | ||
| 337 | * @exception IOException if an I/O error occurs. | ||
| 338 | * @see java.io.FileDescriptor | ||
| 339 | */ | ||
| 340 | public final FileDescriptor getFD() throws IOException { | ||
| 341 | if (fd != null) return fd; | ||
| 342 | throw new IOException(); | ||
| 343 | } | ||
| 344 | |||
| 345 | /** | ||
| 346 | * Returns the unique {@link java.nio.channels.FileChannel FileChannel} | ||
| 347 | * object associated with this file input stream. | ||
| 348 | * | ||
| 349 | * <p> The initial {@link java.nio.channels.FileChannel#position() | ||
| 350 | * </code>position<code>} of the returned channel will be equal to the | ||
| 351 | * number of bytes read from the file so far. Reading bytes from this | ||
| 352 | * stream will increment the channel's position. Changing the channel's | ||
| 353 | * position, either explicitly or by reading, will change this stream's | ||
| 354 | * file position. | ||
| 355 | * | ||
| 356 | * @return the file channel associated with this file input stream | ||
| 357 | * | ||
| 358 | * @since 1.4 | ||
| 359 | * @spec JSR-51 | ||
| 360 | */ | ||
| 361 | public FileChannel getChannel() { | ||
| 362 | synchronized (this) { | ||
| 363 | if (channel == null) { | ||
| 364 | channel = FileChannelImpl.open(fd, true, false, this); | ||
| 365 | |||
| 366 | /* | ||
| 367 | * Increment fd's use count. Invoking the channel's close() | ||
| 368 | * method will result in decrementing the use count set for | ||
| 369 | * the channel. | ||
| 370 | */ | ||
| 371 | fd.incrementAndGetUseCount(); | ||
| 372 | } | ||
| 373 | return channel; | ||
| 374 | } | ||
| 375 | } | ||
| 376 | |||
| 377 | private static native void initIDs(); | ||
| 378 | |||
| 379 | private native void close0() throws IOException; | ||
| 380 | |||
| 381 | static { | ||
| 382 | initIDs(); | ||
| 383 | } | ||
| 384 | |||
| 385 | /** | ||
| 386 | * Ensures that the <code>close</code> method of this file input stream is | ||
| 387 | * called when there are no more references to it. | ||
| 388 | * | ||
| 389 | * @exception IOException if an I/O error occurs. | ||
| 390 | * @see java.io.FileInputStream#close() | ||
| 391 | */ | ||
| 392 | protected void finalize() throws IOException { | ||
| 393 | if ((fd != null) && (fd != FileDescriptor.in)) { | ||
| 394 | |||
| 395 | /* | ||
| 396 | * Finalizer should not release the FileDescriptor if another | ||
| 397 | * stream is still using it. If the user directly invokes | ||
| 398 | * close() then the FileDescriptor is also released. | ||
| 399 | */ | ||
| 400 | runningFinalize.set(Boolean.TRUE); | ||
| 401 | try { | ||
| 402 | close(); | ||
| 403 | } finally { | ||
| 404 | runningFinalize.set(Boolean.FALSE); | ||
| 405 | } | ||
| 406 | } | ||
| 407 | } | ||
| 408 | } | ||