The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 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.content.res; |
| 18 | |
| 19 | import android.os.Parcel; |
| 20 | import android.os.ParcelFileDescriptor; |
| 21 | import android.os.Parcelable; |
| 22 | |
| 23 | import java.io.FileDescriptor; |
| 24 | import java.io.FileInputStream; |
| 25 | import java.io.FileOutputStream; |
| 26 | import java.io.IOException; |
| 27 | |
| 28 | /** |
| 29 | * File descriptor of an entry in the AssetManager. This provides your own |
| 30 | * opened FileDescriptor that can be used to read the data, as well as the |
| 31 | * offset and length of that entry's data in the file. |
| 32 | */ |
| 33 | public class AssetFileDescriptor implements Parcelable { |
| 34 | /** |
| 35 | * Length used with {@link #AssetFileDescriptor(ParcelFileDescriptor, long, long)} |
| 36 | * and {@link #getDeclaredLength} when a length has not been declared. This means |
| 37 | * the data extends to the end of the file. |
| 38 | */ |
| 39 | public static final long UNKNOWN_LENGTH = -1; |
| 40 | |
| 41 | private final ParcelFileDescriptor mFd; |
| 42 | private final long mStartOffset; |
| 43 | private final long mLength; |
| 44 | |
| 45 | /** |
| 46 | * Create a new AssetFileDescriptor from the given values. |
| 47 | * @param fd The underlying file descriptor. |
| 48 | * @param startOffset The location within the file that the asset starts. |
| 49 | * This must be 0 if length is UNKNOWN_LENGTH. |
| 50 | * @param length The number of bytes of the asset, or |
Bjorn Bringert | a006b472 | 2010-04-14 14:43:26 +0100 | [diff] [blame] | 51 | * {@link #UNKNOWN_LENGTH} if it extends to the end of the file. |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 52 | */ |
| 53 | public AssetFileDescriptor(ParcelFileDescriptor fd, long startOffset, |
| 54 | long length) { |
Jeff Brown | af67fc6 | 2012-05-08 14:29:09 -0700 | [diff] [blame] | 55 | if (fd == null) { |
| 56 | throw new IllegalArgumentException("fd must not be null"); |
| 57 | } |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 58 | if (length < 0 && startOffset != 0) { |
| 59 | throw new IllegalArgumentException( |
| 60 | "startOffset must be 0 when using UNKNOWN_LENGTH"); |
| 61 | } |
| 62 | mFd = fd; |
| 63 | mStartOffset = startOffset; |
| 64 | mLength = length; |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * The AssetFileDescriptor contains its own ParcelFileDescriptor, which |
| 69 | * in addition to the normal FileDescriptor object also allows you to close |
| 70 | * the descriptor when you are done with it. |
| 71 | */ |
| 72 | public ParcelFileDescriptor getParcelFileDescriptor() { |
| 73 | return mFd; |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * Returns the FileDescriptor that can be used to read the data in the |
| 78 | * file. |
| 79 | */ |
| 80 | public FileDescriptor getFileDescriptor() { |
| 81 | return mFd.getFileDescriptor(); |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * Returns the byte offset where this asset entry's data starts. |
| 86 | */ |
| 87 | public long getStartOffset() { |
| 88 | return mStartOffset; |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Returns the total number of bytes of this asset entry's data. May be |
| 93 | * {@link #UNKNOWN_LENGTH} if the asset extends to the end of the file. |
| 94 | * If the AssetFileDescriptor was constructed with {@link #UNKNOWN_LENGTH}, |
| 95 | * this will use {@link ParcelFileDescriptor#getStatSize() |
| 96 | * ParcelFileDescriptor.getStatSize()} to find the total size of the file, |
| 97 | * returning that number if found or {@link #UNKNOWN_LENGTH} if it could |
| 98 | * not be determined. |
| 99 | * |
| 100 | * @see #getDeclaredLength() |
| 101 | */ |
| 102 | public long getLength() { |
| 103 | if (mLength >= 0) { |
| 104 | return mLength; |
| 105 | } |
| 106 | long len = mFd.getStatSize(); |
| 107 | return len >= 0 ? len : UNKNOWN_LENGTH; |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Return the actual number of bytes that were declared when the |
| 112 | * AssetFileDescriptor was constructed. Will be |
| 113 | * {@link #UNKNOWN_LENGTH} if the length was not declared, meaning data |
| 114 | * should be read to the end of the file. |
| 115 | * |
| 116 | * @see #getDeclaredLength() |
| 117 | */ |
| 118 | public long getDeclaredLength() { |
| 119 | return mLength; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * Convenience for calling <code>getParcelFileDescriptor().close()</code>. |
| 124 | */ |
| 125 | public void close() throws IOException { |
| 126 | mFd.close(); |
| 127 | } |
Bjorn Bringert | 963cd006 | 2009-05-29 14:05:12 +0100 | [diff] [blame] | 128 | |
| 129 | /** |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 130 | * Create and return a new auto-close input stream for this asset. This |
| 131 | * will either return a full asset {@link AutoCloseInputStream}, or |
| 132 | * an underlying {@link ParcelFileDescriptor.AutoCloseInputStream |
| 133 | * ParcelFileDescriptor.AutoCloseInputStream} depending on whether the |
| 134 | * the object represents a complete file or sub-section of a file. You |
| 135 | * should only call this once for a particular asset. |
| 136 | */ |
| 137 | public FileInputStream createInputStream() throws IOException { |
| 138 | if (mLength < 0) { |
| 139 | return new ParcelFileDescriptor.AutoCloseInputStream(mFd); |
| 140 | } |
| 141 | return new AutoCloseInputStream(this); |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Create and return a new auto-close output stream for this asset. This |
| 146 | * will either return a full asset {@link AutoCloseOutputStream}, or |
| 147 | * an underlying {@link ParcelFileDescriptor.AutoCloseOutputStream |
| 148 | * ParcelFileDescriptor.AutoCloseOutputStream} depending on whether the |
| 149 | * the object represents a complete file or sub-section of a file. You |
| 150 | * should only call this once for a particular asset. |
| 151 | */ |
| 152 | public FileOutputStream createOutputStream() throws IOException { |
| 153 | if (mLength < 0) { |
| 154 | return new ParcelFileDescriptor.AutoCloseOutputStream(mFd); |
| 155 | } |
| 156 | return new AutoCloseOutputStream(this); |
| 157 | } |
| 158 | |
| 159 | @Override |
| 160 | public String toString() { |
| 161 | return "{AssetFileDescriptor: " + mFd |
| 162 | + " start=" + mStartOffset + " len=" + mLength + "}"; |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * An InputStream you can create on a ParcelFileDescriptor, which will |
| 167 | * take care of calling {@link ParcelFileDescriptor#close |
| 168 | * ParcelFileDescritor.close()} for you when the stream is closed. |
| 169 | */ |
| 170 | public static class AutoCloseInputStream |
| 171 | extends ParcelFileDescriptor.AutoCloseInputStream { |
| 172 | private long mRemaining; |
| 173 | |
| 174 | public AutoCloseInputStream(AssetFileDescriptor fd) throws IOException { |
| 175 | super(fd.getParcelFileDescriptor()); |
| 176 | super.skip(fd.getStartOffset()); |
| 177 | mRemaining = (int)fd.getLength(); |
| 178 | } |
| 179 | |
| 180 | @Override |
| 181 | public int available() throws IOException { |
| 182 | return mRemaining >= 0 |
| 183 | ? (mRemaining < 0x7fffffff ? (int)mRemaining : 0x7fffffff) |
| 184 | : super.available(); |
| 185 | } |
| 186 | |
| 187 | @Override |
| 188 | public int read() throws IOException { |
Bjorn Bringert | 2127993 | 2010-12-02 11:34:28 +0000 | [diff] [blame] | 189 | byte[] buffer = new byte[1]; |
| 190 | int result = read(buffer, 0, 1); |
| 191 | return result == -1 ? -1 : buffer[0] & 0xff; |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 192 | } |
| 193 | |
| 194 | @Override |
| 195 | public int read(byte[] buffer, int offset, int count) throws IOException { |
| 196 | if (mRemaining >= 0) { |
| 197 | if (mRemaining == 0) return -1; |
| 198 | if (count > mRemaining) count = (int)mRemaining; |
| 199 | int res = super.read(buffer, offset, count); |
| 200 | if (res >= 0) mRemaining -= res; |
| 201 | return res; |
| 202 | } |
| 203 | |
| 204 | return super.read(buffer, offset, count); |
| 205 | } |
| 206 | |
| 207 | @Override |
| 208 | public int read(byte[] buffer) throws IOException { |
Bjorn Bringert | 2127993 | 2010-12-02 11:34:28 +0000 | [diff] [blame] | 209 | return read(buffer, 0, buffer.length); |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 210 | } |
| 211 | |
| 212 | @Override |
| 213 | public long skip(long count) throws IOException { |
| 214 | if (mRemaining >= 0) { |
| 215 | if (mRemaining == 0) return -1; |
| 216 | if (count > mRemaining) count = mRemaining; |
| 217 | long res = super.skip(count); |
| 218 | if (res >= 0) mRemaining -= res; |
| 219 | return res; |
| 220 | } |
| 221 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 222 | return super.skip(count); |
| 223 | } |
| 224 | |
| 225 | @Override |
| 226 | public void mark(int readlimit) { |
| 227 | if (mRemaining >= 0) { |
| 228 | // Not supported. |
| 229 | return; |
| 230 | } |
| 231 | super.mark(readlimit); |
| 232 | } |
| 233 | |
| 234 | @Override |
| 235 | public boolean markSupported() { |
| 236 | if (mRemaining >= 0) { |
| 237 | return false; |
| 238 | } |
| 239 | return super.markSupported(); |
| 240 | } |
| 241 | |
| 242 | @Override |
| 243 | public synchronized void reset() throws IOException { |
| 244 | if (mRemaining >= 0) { |
| 245 | // Not supported. |
| 246 | return; |
| 247 | } |
| 248 | super.reset(); |
| 249 | } |
| 250 | } |
Bjorn Bringert | 963cd006 | 2009-05-29 14:05:12 +0100 | [diff] [blame] | 251 | |
| 252 | /** |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 253 | * An OutputStream you can create on a ParcelFileDescriptor, which will |
| 254 | * take care of calling {@link ParcelFileDescriptor#close |
| 255 | * ParcelFileDescritor.close()} for you when the stream is closed. |
| 256 | */ |
| 257 | public static class AutoCloseOutputStream |
| 258 | extends ParcelFileDescriptor.AutoCloseOutputStream { |
| 259 | private long mRemaining; |
| 260 | |
| 261 | public AutoCloseOutputStream(AssetFileDescriptor fd) throws IOException { |
| 262 | super(fd.getParcelFileDescriptor()); |
| 263 | if (fd.getParcelFileDescriptor().seekTo(fd.getStartOffset()) < 0) { |
| 264 | throw new IOException("Unable to seek"); |
| 265 | } |
| 266 | mRemaining = (int)fd.getLength(); |
| 267 | } |
| 268 | |
| 269 | @Override |
| 270 | public void write(byte[] buffer, int offset, int count) throws IOException { |
| 271 | if (mRemaining >= 0) { |
| 272 | if (mRemaining == 0) return; |
| 273 | if (count > mRemaining) count = (int)mRemaining; |
| 274 | super.write(buffer, offset, count); |
| 275 | mRemaining -= count; |
| 276 | return; |
| 277 | } |
| 278 | |
| 279 | super.write(buffer, offset, count); |
| 280 | } |
| 281 | |
| 282 | @Override |
| 283 | public void write(byte[] buffer) throws IOException { |
| 284 | if (mRemaining >= 0) { |
| 285 | if (mRemaining == 0) return; |
| 286 | int count = buffer.length; |
| 287 | if (count > mRemaining) count = (int)mRemaining; |
| 288 | super.write(buffer); |
| 289 | mRemaining -= count; |
| 290 | return; |
| 291 | } |
| 292 | |
| 293 | super.write(buffer); |
| 294 | } |
| 295 | |
| 296 | @Override |
| 297 | public void write(int oneByte) throws IOException { |
| 298 | if (mRemaining >= 0) { |
| 299 | if (mRemaining == 0) return; |
| 300 | super.write(oneByte); |
| 301 | mRemaining--; |
| 302 | return; |
| 303 | } |
| 304 | |
| 305 | super.write(oneByte); |
| 306 | } |
| 307 | } |
| 308 | |
| 309 | |
| 310 | /* Parcelable interface */ |
| 311 | public int describeContents() { |
| 312 | return mFd.describeContents(); |
| 313 | } |
| 314 | |
| 315 | public void writeToParcel(Parcel out, int flags) { |
| 316 | mFd.writeToParcel(out, flags); |
| 317 | out.writeLong(mStartOffset); |
| 318 | out.writeLong(mLength); |
| 319 | } |
| 320 | |
| 321 | AssetFileDescriptor(Parcel src) { |
| 322 | mFd = ParcelFileDescriptor.CREATOR.createFromParcel(src); |
| 323 | mStartOffset = src.readLong(); |
| 324 | mLength = src.readLong(); |
| 325 | } |
| 326 | |
| 327 | public static final Parcelable.Creator<AssetFileDescriptor> CREATOR |
| 328 | = new Parcelable.Creator<AssetFileDescriptor>() { |
| 329 | public AssetFileDescriptor createFromParcel(Parcel in) { |
| 330 | return new AssetFileDescriptor(in); |
| 331 | } |
| 332 | public AssetFileDescriptor[] newArray(int size) { |
| 333 | return new AssetFileDescriptor[size]; |
| 334 | } |
| 335 | }; |
Bjorn Bringert | 963cd006 | 2009-05-29 14:05:12 +0100 | [diff] [blame] | 336 | |
The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 337 | } |