1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.os; 18 import java.io.Closeable; 19 import java.io.File; 20 import java.io.FileDescriptor; 21 import java.io.FileInputStream; 22 import java.io.FileNotFoundException; 23 import java.io.FileOutputStream; 24 import java.io.IOException; 25 import java.net.DatagramSocket; 26 import java.net.Socket; 27 28 /** 29 * The FileDescriptor returned by {@link Parcel#readFileDescriptor}, allowing 30 * you to close it when done with it. 31 */ 32 public class ParcelFileDescriptor implements Parcelable, Closeable { 33 private final FileDescriptor mFileDescriptor; 34 private boolean mClosed; 35 //this field is to create wrapper for ParcelFileDescriptor using another 36 //PartialFileDescriptor but avoid invoking close twice 37 //consider ParcelFileDescriptor A(fileDescriptor fd), ParcelFileDescriptor B(A) 38 //in this particular case fd.close might be invoked twice. 39 private final ParcelFileDescriptor mParcelDescriptor; 40 41 /** 42 * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied 43 * and this file doesn't already exist, then create the file with 44 * permissions such that any application can read it. 45 */ 46 public static final int MODE_WORLD_READABLE = 0x00000001; 47 48 /** 49 * For use with {@link #open}: if {@link #MODE_CREATE} has been supplied 50 * and this file doesn't already exist, then create the file with 51 * permissions such that any application can write it. 52 */ 53 public static final int MODE_WORLD_WRITEABLE = 0x00000002; 54 55 /** 56 * For use with {@link #open}: open the file with read-only access. 57 */ 58 public static final int MODE_READ_ONLY = 0x10000000; 59 60 /** 61 * For use with {@link #open}: open the file with write-only access. 62 */ 63 public static final int MODE_WRITE_ONLY = 0x20000000; 64 65 /** 66 * For use with {@link #open}: open the file with read and write access. 67 */ 68 public static final int MODE_READ_WRITE = 0x30000000; 69 70 /** 71 * For use with {@link #open}: create the file if it doesn't already exist. 72 */ 73 public static final int MODE_CREATE = 0x08000000; 74 75 /** 76 * For use with {@link #open}: erase contents of file when opening. 77 */ 78 public static final int MODE_TRUNCATE = 0x04000000; 79 80 /** 81 * For use with {@link #open}: append to end of file while writing. 82 */ 83 public static final int MODE_APPEND = 0x02000000; 84 85 /** 86 * Create a new ParcelFileDescriptor accessing a given file. 87 * 88 * @param file The file to be opened. 89 * @param mode The desired access mode, must be one of 90 * {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or 91 * {@link #MODE_READ_WRITE}; may also be any combination of 92 * {@link #MODE_CREATE}, {@link #MODE_TRUNCATE}, 93 * {@link #MODE_WORLD_READABLE}, and {@link #MODE_WORLD_WRITEABLE}. 94 * 95 * @return Returns a new ParcelFileDescriptor pointing to the given 96 * file. 97 * 98 * @throws FileNotFoundException Throws FileNotFoundException if the given 99 * file does not exist or can not be opened with the requested mode. 100 */ open(File file, int mode)101 public static ParcelFileDescriptor open(File file, int mode) 102 throws FileNotFoundException { 103 String path = file.getPath(); 104 SecurityManager security = System.getSecurityManager(); 105 if (security != null) { 106 security.checkRead(path); 107 if ((mode&MODE_WRITE_ONLY) != 0) { 108 security.checkWrite(path); 109 } 110 } 111 112 if ((mode&MODE_READ_WRITE) == 0) { 113 throw new IllegalArgumentException( 114 "Must specify MODE_READ_ONLY, MODE_WRITE_ONLY, or MODE_READ_WRITE"); 115 } 116 117 FileDescriptor fd = Parcel.openFileDescriptor(path, mode); 118 return fd != null ? new ParcelFileDescriptor(fd) : null; 119 } 120 121 /** 122 * Create a new ParcelFileDescriptor that is a dup of an existing 123 * FileDescriptor. This obeys standard POSIX semantics, where the 124 * new file descriptor shared state such as file position with the 125 * original file descriptor. 126 */ dup(FileDescriptor orig)127 public static ParcelFileDescriptor dup(FileDescriptor orig) throws IOException { 128 FileDescriptor fd = Parcel.dupFileDescriptor(orig); 129 return fd != null ? new ParcelFileDescriptor(fd) : null; 130 } 131 132 /** 133 * Create a new ParcelFileDescriptor that is a dup of the existing 134 * FileDescriptor. This obeys standard POSIX semantics, where the 135 * new file descriptor shared state such as file position with the 136 * original file descriptor. 137 */ dup()138 public ParcelFileDescriptor dup() throws IOException { 139 return dup(getFileDescriptor()); 140 } 141 142 /** 143 * Create a new ParcelFileDescriptor from a raw native fd. The new 144 * ParcelFileDescriptor holds a dup of the original fd passed in here, 145 * so you must still close that fd as well as the new ParcelFileDescriptor. 146 * 147 * @param fd The native fd that the ParcelFileDescriptor should dup. 148 * 149 * @return Returns a new ParcelFileDescriptor holding a FileDescriptor 150 * for a dup of the given fd. 151 */ fromFd(int fd)152 public static ParcelFileDescriptor fromFd(int fd) throws IOException { 153 FileDescriptor fdesc = getFileDescriptorFromFd(fd); 154 return new ParcelFileDescriptor(fdesc); 155 } 156 157 // Extracts the file descriptor from the specified socket and returns it untouched getFileDescriptorFromFd(int fd)158 private static native FileDescriptor getFileDescriptorFromFd(int fd) throws IOException; 159 160 /** 161 * Take ownership of a raw native fd in to a new ParcelFileDescriptor. 162 * The returned ParcelFileDescriptor now owns the given fd, and will be 163 * responsible for closing it. You must not close the fd yourself. 164 * 165 * @param fd The native fd that the ParcelFileDescriptor should adopt. 166 * 167 * @return Returns a new ParcelFileDescriptor holding a FileDescriptor 168 * for the given fd. 169 */ adoptFd(int fd)170 public static ParcelFileDescriptor adoptFd(int fd) { 171 FileDescriptor fdesc = getFileDescriptorFromFdNoDup(fd); 172 return new ParcelFileDescriptor(fdesc); 173 } 174 175 // Extracts the file descriptor from the specified socket and returns it untouched getFileDescriptorFromFdNoDup(int fd)176 private static native FileDescriptor getFileDescriptorFromFdNoDup(int fd); 177 178 /** 179 * Create a new ParcelFileDescriptor from the specified Socket. The new 180 * ParcelFileDescriptor holds a dup of the original FileDescriptor in 181 * the Socket, so you must still close the Socket as well as the new 182 * ParcelFileDescriptor. 183 * 184 * @param socket The Socket whose FileDescriptor is used to create 185 * a new ParcelFileDescriptor. 186 * 187 * @return A new ParcelFileDescriptor with the FileDescriptor of the 188 * specified Socket. 189 */ fromSocket(Socket socket)190 public static ParcelFileDescriptor fromSocket(Socket socket) { 191 FileDescriptor fd = socket.getFileDescriptor$(); 192 return fd != null ? new ParcelFileDescriptor(fd) : null; 193 } 194 195 /** 196 * Create a new ParcelFileDescriptor from the specified DatagramSocket. 197 * 198 * @param datagramSocket The DatagramSocket whose FileDescriptor is used 199 * to create a new ParcelFileDescriptor. 200 * 201 * @return A new ParcelFileDescriptor with the FileDescriptor of the 202 * specified DatagramSocket. 203 */ fromDatagramSocket(DatagramSocket datagramSocket)204 public static ParcelFileDescriptor fromDatagramSocket(DatagramSocket datagramSocket) { 205 FileDescriptor fd = datagramSocket.getFileDescriptor$(); 206 return fd != null ? new ParcelFileDescriptor(fd) : null; 207 } 208 209 /** 210 * Create two ParcelFileDescriptors structured as a data pipe. The first 211 * ParcelFileDescriptor in the returned array is the read side; the second 212 * is the write side. 213 */ createPipe()214 public static ParcelFileDescriptor[] createPipe() throws IOException { 215 FileDescriptor[] fds = new FileDescriptor[2]; 216 createPipeNative(fds); 217 ParcelFileDescriptor[] pfds = new ParcelFileDescriptor[2]; 218 pfds[0] = new ParcelFileDescriptor(fds[0]); 219 pfds[1] = new ParcelFileDescriptor(fds[1]); 220 return pfds; 221 } 222 createPipeNative(FileDescriptor[] outFds)223 private static native void createPipeNative(FileDescriptor[] outFds) throws IOException; 224 225 /** 226 * @hide Please use createPipe() or ContentProvider.openPipeHelper(). 227 * Gets a file descriptor for a read-only copy of the given data. 228 * 229 * @param data Data to copy. 230 * @param name Name for the shared memory area that may back the file descriptor. 231 * This is purely informative and may be {@code null}. 232 * @return A ParcelFileDescriptor. 233 * @throws IOException if there is an error while creating the shared memory area. 234 */ 235 @Deprecated fromData(byte[] data, String name)236 public static ParcelFileDescriptor fromData(byte[] data, String name) throws IOException { 237 if (data == null) return null; 238 MemoryFile file = new MemoryFile(name, data.length); 239 if (data.length > 0) { 240 file.writeBytes(data, 0, 0, data.length); 241 } 242 file.deactivate(); 243 FileDescriptor fd = file.getFileDescriptor(); 244 return fd != null ? new ParcelFileDescriptor(fd) : null; 245 } 246 247 /** 248 * Retrieve the actual FileDescriptor associated with this object. 249 * 250 * @return Returns the FileDescriptor associated with this object. 251 */ getFileDescriptor()252 public FileDescriptor getFileDescriptor() { 253 return mFileDescriptor; 254 } 255 256 /** 257 * Return the total size of the file representing this fd, as determined 258 * by stat(). Returns -1 if the fd is not a file. 259 */ getStatSize()260 public native long getStatSize(); 261 262 /** 263 * This is needed for implementing AssetFileDescriptor.AutoCloseOutputStream, 264 * and I really don't think we want it to be public. 265 * @hide 266 */ seekTo(long pos)267 public native long seekTo(long pos); 268 269 /** 270 * Return the native fd int for this ParcelFileDescriptor. The 271 * ParcelFileDescriptor still owns the fd, and it still must be closed 272 * through this API. 273 */ getFd()274 public int getFd() { 275 if (mClosed) { 276 throw new IllegalStateException("Already closed"); 277 } 278 return getFdNative(); 279 } 280 getFdNative()281 private native int getFdNative(); 282 283 /** 284 * Return the native fd int for this ParcelFileDescriptor and detach it 285 * from the object here. You are now responsible for closing the fd in 286 * native code. 287 */ detachFd()288 public int detachFd() { 289 if (mClosed) { 290 throw new IllegalStateException("Already closed"); 291 } 292 if (mParcelDescriptor != null) { 293 int fd = mParcelDescriptor.detachFd(); 294 mClosed = true; 295 return fd; 296 } 297 int fd = getFd(); 298 mClosed = true; 299 Parcel.clearFileDescriptor(mFileDescriptor); 300 return fd; 301 } 302 303 /** 304 * Close the ParcelFileDescriptor. This implementation closes the underlying 305 * OS resources allocated to represent this stream. 306 * 307 * @throws IOException 308 * If an error occurs attempting to close this ParcelFileDescriptor. 309 */ close()310 public void close() throws IOException { 311 synchronized (this) { 312 if (mClosed) return; 313 mClosed = true; 314 } 315 if (mParcelDescriptor != null) { 316 // If this is a proxy to another file descriptor, just call through to its 317 // close method. 318 mParcelDescriptor.close(); 319 } else { 320 Parcel.closeFileDescriptor(mFileDescriptor); 321 } 322 } 323 324 /** 325 * An InputStream you can create on a ParcelFileDescriptor, which will 326 * take care of calling {@link ParcelFileDescriptor#close 327 * ParcelFileDescriptor.close()} for you when the stream is closed. 328 */ 329 public static class AutoCloseInputStream extends FileInputStream { 330 private final ParcelFileDescriptor mFd; 331 AutoCloseInputStream(ParcelFileDescriptor fd)332 public AutoCloseInputStream(ParcelFileDescriptor fd) { 333 super(fd.getFileDescriptor()); 334 mFd = fd; 335 } 336 337 @Override close()338 public void close() throws IOException { 339 try { 340 mFd.close(); 341 } finally { 342 super.close(); 343 } 344 } 345 } 346 347 /** 348 * An OutputStream you can create on a ParcelFileDescriptor, which will 349 * take care of calling {@link ParcelFileDescriptor#close 350 * ParcelFileDescriptor.close()} for you when the stream is closed. 351 */ 352 public static class AutoCloseOutputStream extends FileOutputStream { 353 private final ParcelFileDescriptor mFd; 354 AutoCloseOutputStream(ParcelFileDescriptor fd)355 public AutoCloseOutputStream(ParcelFileDescriptor fd) { 356 super(fd.getFileDescriptor()); 357 mFd = fd; 358 } 359 360 @Override close()361 public void close() throws IOException { 362 try { 363 mFd.close(); 364 } finally { 365 super.close(); 366 } 367 } 368 } 369 370 @Override toString()371 public String toString() { 372 return "{ParcelFileDescriptor: " + mFileDescriptor + "}"; 373 } 374 375 @Override finalize()376 protected void finalize() throws Throwable { 377 try { 378 if (!mClosed) { 379 close(); 380 } 381 } finally { 382 super.finalize(); 383 } 384 } 385 ParcelFileDescriptor(ParcelFileDescriptor descriptor)386 public ParcelFileDescriptor(ParcelFileDescriptor descriptor) { 387 super(); 388 mParcelDescriptor = descriptor; 389 mFileDescriptor = mParcelDescriptor.mFileDescriptor; 390 } 391 ParcelFileDescriptor(FileDescriptor descriptor)392 /*package */ParcelFileDescriptor(FileDescriptor descriptor) { 393 super(); 394 if (descriptor == null) { 395 throw new NullPointerException("descriptor must not be null"); 396 } 397 mFileDescriptor = descriptor; 398 mParcelDescriptor = null; 399 } 400 401 /* Parcelable interface */ describeContents()402 public int describeContents() { 403 return Parcelable.CONTENTS_FILE_DESCRIPTOR; 404 } 405 406 /** 407 * {@inheritDoc} 408 * If {@link Parcelable#PARCELABLE_WRITE_RETURN_VALUE} is set in flags, 409 * the file descriptor will be closed after a copy is written to the Parcel. 410 */ writeToParcel(Parcel out, int flags)411 public void writeToParcel(Parcel out, int flags) { 412 out.writeFileDescriptor(mFileDescriptor); 413 if ((flags&PARCELABLE_WRITE_RETURN_VALUE) != 0 && !mClosed) { 414 try { 415 close(); 416 } catch (IOException e) { 417 // Empty 418 } 419 } 420 } 421 422 public static final Parcelable.Creator<ParcelFileDescriptor> CREATOR 423 = new Parcelable.Creator<ParcelFileDescriptor>() { 424 public ParcelFileDescriptor createFromParcel(Parcel in) { 425 return in.readFileDescriptor(); 426 } 427 public ParcelFileDescriptor[] newArray(int size) { 428 return new ParcelFileDescriptor[size]; 429 } 430 }; 431 432 } 433