| 1 | package be.nikiroo.utils; |
| 2 | |
| 3 | import java.io.File; |
| 4 | import java.io.FileInputStream; |
| 5 | import java.io.FileNotFoundException; |
| 6 | import java.io.IOException; |
| 7 | import java.io.InputStream; |
| 8 | import java.net.URL; |
| 9 | import java.util.Date; |
| 10 | |
| 11 | /** |
| 12 | * A generic cache system, with special support for {@link URL}s. |
| 13 | * <p> |
| 14 | * This cache also manages timeout information. |
| 15 | * |
| 16 | * @author niki |
| 17 | */ |
| 18 | public class Cache { |
| 19 | private File dir; |
| 20 | private long tooOldChanging; |
| 21 | private long tooOldStable; |
| 22 | private TraceHandler tracer = new TraceHandler(); |
| 23 | |
| 24 | /** |
| 25 | * Create a new {@link Cache} object. |
| 26 | * |
| 27 | * @param dir |
| 28 | * the directory to use as cache |
| 29 | * @param hoursChanging |
| 30 | * the number of hours after which a cached file that is thought |
| 31 | * to change ~often is considered too old (or -1 for |
| 32 | * "never too old") |
| 33 | * @param hoursStable |
| 34 | * the number of hours after which a cached file that is thought |
| 35 | * to change rarely is considered too old (or -1 for |
| 36 | * "never too old") |
| 37 | * |
| 38 | * @throws IOException |
| 39 | * in case of I/O error |
| 40 | */ |
| 41 | public Cache(File dir, int hoursChanging, int hoursStable) |
| 42 | throws IOException { |
| 43 | this.dir = dir; |
| 44 | this.tooOldChanging = 1000 * 60 * 60 * hoursChanging; |
| 45 | this.tooOldStable = 1000 * 60 * 60 * hoursStable; |
| 46 | |
| 47 | if (dir != null && !dir.exists()) { |
| 48 | dir.mkdirs(); |
| 49 | } |
| 50 | |
| 51 | if (dir == null || !dir.exists()) { |
| 52 | throw new IOException("Cannot create the cache directory: " |
| 53 | + (dir == null ? "null" : dir.getAbsolutePath())); |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | /** |
| 58 | * The traces handler for this {@link Cache}. |
| 59 | * |
| 60 | * @return the traces handler |
| 61 | */ |
| 62 | public TraceHandler getTraceHandler() { |
| 63 | return tracer; |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * The traces handler for this {@link Cache}. |
| 68 | * |
| 69 | * @param tracer |
| 70 | * the new traces handler |
| 71 | */ |
| 72 | public void setTraceHandler(TraceHandler tracer) { |
| 73 | if (tracer == null) { |
| 74 | tracer = new TraceHandler(false, false, false); |
| 75 | } |
| 76 | |
| 77 | this.tracer = tracer; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Check the resource to see if it is in the cache. |
| 82 | * |
| 83 | * @param url |
| 84 | * the resource to check |
| 85 | * @param allowTooOld |
| 86 | * allow files even if they are considered too old |
| 87 | * @param stable |
| 88 | * a stable file (that dones't change too often) -- parameter |
| 89 | * used to check if the file is too old to keep or not |
| 90 | * |
| 91 | * @return TRUE if it is |
| 92 | * |
| 93 | */ |
| 94 | public boolean check(URL url, boolean allowTooOld, boolean stable) { |
| 95 | File file = getCached(url); |
| 96 | if (file.exists() && file.isFile()) { |
| 97 | if (allowTooOld || !isOld(file, stable)) { |
| 98 | return true; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | return false; |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Clean the cache (delete the cached items). |
| 107 | * |
| 108 | * @param onlyOld |
| 109 | * only clean the files that are considered too old for a stable |
| 110 | * resource |
| 111 | * |
| 112 | * @return the number of cleaned items |
| 113 | */ |
| 114 | public int clean(boolean onlyOld) { |
| 115 | return clean(onlyOld, dir); |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Clean the cache (delete the cached items) in the given cache directory. |
| 120 | * |
| 121 | * @param onlyOld |
| 122 | * only clean the files that are considered too old for stable |
| 123 | * resources |
| 124 | * @param cacheDir |
| 125 | * the cache directory to clean |
| 126 | * |
| 127 | * @return the number of cleaned items |
| 128 | */ |
| 129 | private int clean(boolean onlyOld, File cacheDir) { |
| 130 | int num = 0; |
| 131 | for (File file : cacheDir.listFiles()) { |
| 132 | if (file.isDirectory()) { |
| 133 | num += clean(onlyOld, file); |
| 134 | } else { |
| 135 | if (!onlyOld || isOld(file, true)) { |
| 136 | if (file.delete()) { |
| 137 | num++; |
| 138 | } else { |
| 139 | tracer.error("Cannot delete temporary file: " |
| 140 | + file.getAbsolutePath()); |
| 141 | } |
| 142 | } |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | return num; |
| 147 | } |
| 148 | |
| 149 | /** |
| 150 | * Open a resource from the cache if it exists. |
| 151 | * |
| 152 | * @param uniqueID |
| 153 | * the unique ID |
| 154 | * @param allowTooOld |
| 155 | * allow files even if they are considered too old |
| 156 | * @param stable |
| 157 | * a stable file (that dones't change too often) -- parameter |
| 158 | * used to check if the file is too old to keep or not |
| 159 | * |
| 160 | * @return the opened resource if found, NULL if not |
| 161 | */ |
| 162 | public InputStream load(String uniqueID, boolean allowTooOld, boolean stable) { |
| 163 | return load(getCached(uniqueID), allowTooOld, stable); |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Open a resource from the cache if it exists. |
| 168 | * |
| 169 | * @param url |
| 170 | * the resource to open |
| 171 | * @param allowTooOld |
| 172 | * allow files even if they are considered too old |
| 173 | * @param stable |
| 174 | * a stable file (that dones't change too often) -- parameter |
| 175 | * used to check if the file is too old to keep or not |
| 176 | * |
| 177 | * @return the opened resource if found, NULL if not |
| 178 | */ |
| 179 | public InputStream load(URL url, boolean allowTooOld, boolean stable) { |
| 180 | return load(getCached(url), allowTooOld, stable); |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * Open a resource from the cache if it exists. |
| 185 | * |
| 186 | * @param cached |
| 187 | * the resource to open |
| 188 | * @param allowTooOld |
| 189 | * allow files even if they are considered too old |
| 190 | * @param stable |
| 191 | * a stable file (that dones't change too often) -- parameter |
| 192 | * used to check if the file is too old to keep or not |
| 193 | * |
| 194 | * @return the opened resource if found, NULL if not |
| 195 | */ |
| 196 | private InputStream load(File cached, boolean allowTooOld, boolean stable) { |
| 197 | if (cached.exists() && cached.isFile() |
| 198 | && (allowTooOld || !isOld(cached, stable))) { |
| 199 | try { |
| 200 | return new MarkableFileInputStream(new FileInputStream(cached)); |
| 201 | } catch (FileNotFoundException e) { |
| 202 | return null; |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | return null; |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Save the given resource to the cache. |
| 211 | * |
| 212 | * @param in |
| 213 | * the input data |
| 214 | * @param uniqueID |
| 215 | * a unique ID used to locate the cached resource |
| 216 | * |
| 217 | * @return the resulting {@link File} |
| 218 | * |
| 219 | * @throws IOException |
| 220 | * in case of I/O error |
| 221 | */ |
| 222 | public File save(InputStream in, String uniqueID) throws IOException { |
| 223 | File cached = getCached(uniqueID); |
| 224 | cached.getParentFile().mkdirs(); |
| 225 | return save(in, cached); |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * Save the given resource to the cache. |
| 230 | * |
| 231 | * @param in |
| 232 | * the input data |
| 233 | * @param url |
| 234 | * the {@link URL} used to locate the cached resource |
| 235 | * |
| 236 | * @return the actual cache file |
| 237 | * |
| 238 | * @throws IOException |
| 239 | * in case of I/O error |
| 240 | */ |
| 241 | public File save(InputStream in, URL url) throws IOException { |
| 242 | File cached = getCached(url); |
| 243 | return save(in, cached); |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * Save the given resource to the cache. |
| 248 | * |
| 249 | * @param in |
| 250 | * the input data |
| 251 | * @param cached |
| 252 | * the cached {@link File} to save to |
| 253 | * |
| 254 | * @return the actual cache file |
| 255 | * |
| 256 | * @throws IOException |
| 257 | * in case of I/O error |
| 258 | */ |
| 259 | private File save(InputStream in, File cached) throws IOException { |
| 260 | IOUtils.write(in, cached); |
| 261 | return cached; |
| 262 | } |
| 263 | |
| 264 | /** |
| 265 | * Remove the given resource from the cache. |
| 266 | * |
| 267 | * @param uniqueID |
| 268 | * a unique ID used to locate the cached resource |
| 269 | * |
| 270 | * @return TRUE if it was removed |
| 271 | */ |
| 272 | public boolean remove(String uniqueID) { |
| 273 | File cached = getCached(uniqueID); |
| 274 | return cached.delete(); |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Remove the given resource from the cache. |
| 279 | * |
| 280 | * @param url |
| 281 | * the {@link URL} used to locate the cached resource |
| 282 | * |
| 283 | * @return TRUE if it was removed |
| 284 | */ |
| 285 | public boolean remove(URL url) { |
| 286 | File cached = getCached(url); |
| 287 | return cached.delete(); |
| 288 | } |
| 289 | |
| 290 | /** |
| 291 | * Check if the {@link File} is too old according to |
| 292 | * {@link Cache#tooOldChanging}. |
| 293 | * |
| 294 | * @param file |
| 295 | * the file to check |
| 296 | * @param stable |
| 297 | * TRUE to denote stable files, that are not supposed to change |
| 298 | * too often |
| 299 | * |
| 300 | * @return TRUE if it is |
| 301 | */ |
| 302 | private boolean isOld(File file, boolean stable) { |
| 303 | long max = tooOldChanging; |
| 304 | if (stable) { |
| 305 | max = tooOldStable; |
| 306 | } |
| 307 | |
| 308 | if (max < 0) { |
| 309 | return false; |
| 310 | } |
| 311 | |
| 312 | long time = new Date().getTime() - file.lastModified(); |
| 313 | if (time < 0) { |
| 314 | tracer.error("Timestamp in the future for file: " |
| 315 | + file.getAbsolutePath()); |
| 316 | } |
| 317 | |
| 318 | return time < 0 || time > max; |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Return the associated cache {@link File} from this {@link URL}. |
| 323 | * |
| 324 | * @param url |
| 325 | * the {@link URL} |
| 326 | * |
| 327 | * @return the cached {@link File} version of this {@link URL} |
| 328 | */ |
| 329 | private File getCached(URL url) { |
| 330 | File subdir; |
| 331 | |
| 332 | String name = url.getHost(); |
| 333 | if (name == null || name.isEmpty()) { |
| 334 | // File |
| 335 | File file = new File(url.getFile()); |
| 336 | if (file.getParent() == null) { |
| 337 | subdir = new File("+"); |
| 338 | } else { |
| 339 | subdir = new File(file.getParent().replace("..", "__")); |
| 340 | } |
| 341 | subdir = new File(dir, allowedChars(subdir.getPath())); |
| 342 | name = allowedChars(url.getFile()); |
| 343 | } else { |
| 344 | // URL |
| 345 | File subsubDir = new File(dir, allowedChars(url.getHost())); |
| 346 | subdir = new File(subsubDir, "_" + allowedChars(url.getPath())); |
| 347 | name = allowedChars("_" + url.getQuery()); |
| 348 | } |
| 349 | |
| 350 | File cacheFile = new File(subdir, name); |
| 351 | subdir.mkdirs(); |
| 352 | |
| 353 | return cacheFile; |
| 354 | } |
| 355 | |
| 356 | /** |
| 357 | * Get the basic cache resource file corresponding to this unique ID. |
| 358 | * <p> |
| 359 | * Note that you may need to add a sub-directory in some cases. |
| 360 | * |
| 361 | * @param uniqueID |
| 362 | * the id |
| 363 | * |
| 364 | * @return the cached version if present, NULL if not |
| 365 | */ |
| 366 | private File getCached(String uniqueID) { |
| 367 | File file = new File(dir, allowedChars(uniqueID)); |
| 368 | File subdir = new File(file.getParentFile(), "_"); |
| 369 | return new File(subdir, file.getName()); |
| 370 | } |
| 371 | |
| 372 | /** |
| 373 | * Replace not allowed chars (in a {@link File}) by "_". |
| 374 | * |
| 375 | * @param raw |
| 376 | * the raw {@link String} |
| 377 | * |
| 378 | * @return the sanitised {@link String} |
| 379 | */ |
| 380 | private String allowedChars(String raw) { |
| 381 | return raw.replace('/', '_').replace(':', '_').replace("\\", "_"); |
| 382 | } |
| 383 | } |