TaskPersister.java revision 63f10904a17db79cc8da08ff904d45d6d1cf0862
1/* 2 * Copyright (C) 2014 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 17package com.android.server.am; 18 19import android.graphics.Bitmap; 20import android.graphics.BitmapFactory; 21import android.os.Debug; 22import android.os.SystemClock; 23import android.util.ArraySet; 24import android.util.AtomicFile; 25import android.util.Slog; 26import android.util.Xml; 27import com.android.internal.util.FastXmlSerializer; 28import com.android.internal.util.XmlUtils; 29import org.xmlpull.v1.XmlPullParser; 30import org.xmlpull.v1.XmlPullParserException; 31import org.xmlpull.v1.XmlSerializer; 32 33import java.io.BufferedReader; 34import java.io.File; 35import java.io.FileOutputStream; 36import java.io.FileReader; 37import java.io.IOException; 38import java.io.StringWriter; 39import java.util.ArrayList; 40import java.util.Arrays; 41import java.util.Comparator; 42 43public class TaskPersister { 44 static final String TAG = "TaskPersister"; 45 static final boolean DEBUG = false; 46 47 /** When not flushing don't write out files faster than this */ 48 private static final long INTER_WRITE_DELAY_MS = 500; 49 50 /** When not flushing delay this long before writing the first file out. This gives the next 51 * task being launched a chance to load its resources without this occupying IO bandwidth. */ 52 private static final long PRE_TASK_DELAY_MS = 3000; 53 54 /** The maximum number of entries to keep in the queue before draining it automatically. */ 55 private static final int MAX_WRITE_QUEUE_LENGTH = 6; 56 57 /** Special value for mWriteTime to mean don't wait, just write */ 58 private static final long FLUSH_QUEUE = -1; 59 60 private static final String RECENTS_FILENAME = "_task"; 61 private static final String TASKS_DIRNAME = "recent_tasks"; 62 private static final String TASK_EXTENSION = ".xml"; 63 private static final String IMAGES_DIRNAME = "recent_images"; 64 static final String IMAGE_EXTENSION = ".png"; 65 66 private static final String TAG_TASK = "task"; 67 68 static File sImagesDir; 69 static File sTasksDir; 70 71 private final ActivityManagerService mService; 72 private final ActivityStackSupervisor mStackSupervisor; 73 74 /** Value determines write delay mode as follows: 75 * < 0 We are Flushing. No delays between writes until the image queue is drained and all 76 * tasks needing persisting are written to disk. There is no delay between writes. 77 * == 0 We are Idle. Next writes will be delayed by #PRE_TASK_DELAY_MS. 78 * > 0 We are Actively writing. Next write will be at this time. Subsequent writes will be 79 * delayed by #INTER_WRITE_DELAY_MS. */ 80 private long mNextWriteTime = 0; 81 82 private final LazyTaskWriterThread mLazyTaskWriterThread; 83 84 private static class WriteQueueItem {} 85 private static class TaskWriteQueueItem extends WriteQueueItem { 86 final TaskRecord mTask; 87 TaskWriteQueueItem(TaskRecord task) { 88 mTask = task; 89 } 90 } 91 private static class ImageWriteQueueItem extends WriteQueueItem { 92 final String mFilename; 93 Bitmap mImage; 94 ImageWriteQueueItem(String filename, Bitmap image) { 95 mFilename = filename; 96 mImage = image; 97 } 98 } 99 100 ArrayList<WriteQueueItem> mWriteQueue = new ArrayList<WriteQueueItem>(); 101 102 TaskPersister(File systemDir, ActivityStackSupervisor stackSupervisor) { 103 sTasksDir = new File(systemDir, TASKS_DIRNAME); 104 if (!sTasksDir.exists()) { 105 if (DEBUG) Slog.d(TAG, "Creating tasks directory " + sTasksDir); 106 if (!sTasksDir.mkdir()) { 107 Slog.e(TAG, "Failure creating tasks directory " + sTasksDir); 108 } 109 } 110 111 sImagesDir = new File(systemDir, IMAGES_DIRNAME); 112 if (!sImagesDir.exists()) { 113 if (DEBUG) Slog.d(TAG, "Creating images directory " + sTasksDir); 114 if (!sImagesDir.mkdir()) { 115 Slog.e(TAG, "Failure creating images directory " + sImagesDir); 116 } 117 } 118 119 mStackSupervisor = stackSupervisor; 120 mService = stackSupervisor.mService; 121 122 mLazyTaskWriterThread = new LazyTaskWriterThread("LazyTaskWriterThread"); 123 } 124 125 void startPersisting() { 126 mLazyTaskWriterThread.start(); 127 } 128 129 private void removeThumbnails(TaskRecord task) { 130 final String taskString = Integer.toString(task.taskId); 131 for (int queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) { 132 final WriteQueueItem item = mWriteQueue.get(queueNdx); 133 if (item instanceof ImageWriteQueueItem && 134 ((ImageWriteQueueItem) item).mFilename.startsWith(taskString)) { 135 if (DEBUG) Slog.d(TAG, "Removing " + ((ImageWriteQueueItem) item).mFilename + 136 " from write queue"); 137 mWriteQueue.remove(queueNdx); 138 } 139 } 140 } 141 142 private void yieldIfQueueTooDeep() { 143 boolean stall = false; 144 synchronized (this) { 145 if (mNextWriteTime == FLUSH_QUEUE) { 146 stall = true; 147 } 148 } 149 if (stall) { 150 Thread.yield(); 151 } 152 } 153 154 void wakeup(TaskRecord task, boolean flush) { 155 synchronized (this) { 156 if (task != null) { 157 int queueNdx; 158 for (queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) { 159 final WriteQueueItem item = mWriteQueue.get(queueNdx); 160 if (item instanceof TaskWriteQueueItem && 161 ((TaskWriteQueueItem) item).mTask == task) { 162 if (!task.inRecents) { 163 // This task is being removed. 164 removeThumbnails(task); 165 } 166 break; 167 } 168 } 169 if (queueNdx < 0) { 170 mWriteQueue.add(new TaskWriteQueueItem(task)); 171 } 172 } else { 173 // Dummy. 174 mWriteQueue.add(new WriteQueueItem()); 175 } 176 if (flush || mWriteQueue.size() > MAX_WRITE_QUEUE_LENGTH) { 177 mNextWriteTime = FLUSH_QUEUE; 178 } else if (mNextWriteTime == 0) { 179 mNextWriteTime = SystemClock.uptimeMillis() + PRE_TASK_DELAY_MS; 180 } 181 if (DEBUG) Slog.d(TAG, "wakeup: task=" + task + " flush=" + flush + " mNextWriteTime=" 182 + mNextWriteTime + " mWriteQueue.size=" + mWriteQueue.size() 183 + " Callers=" + Debug.getCallers(4)); 184 notifyAll(); 185 } 186 187 yieldIfQueueTooDeep(); 188 } 189 190 void saveImage(Bitmap image, String filename) { 191 synchronized (this) { 192 int queueNdx; 193 for (queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) { 194 final WriteQueueItem item = mWriteQueue.get(queueNdx); 195 if (item instanceof ImageWriteQueueItem) { 196 ImageWriteQueueItem imageWriteQueueItem = (ImageWriteQueueItem) item; 197 if (imageWriteQueueItem.mFilename.equals(filename)) { 198 // replace the Bitmap with the new one. 199 imageWriteQueueItem.mImage = image; 200 break; 201 } 202 } 203 } 204 if (queueNdx < 0) { 205 mWriteQueue.add(new ImageWriteQueueItem(filename, image)); 206 } 207 if (mWriteQueue.size() > MAX_WRITE_QUEUE_LENGTH) { 208 mNextWriteTime = FLUSH_QUEUE; 209 } else if (mNextWriteTime == 0) { 210 mNextWriteTime = SystemClock.uptimeMillis() + PRE_TASK_DELAY_MS; 211 } 212 if (DEBUG) Slog.d(TAG, "saveImage: filename=" + filename + " now=" + 213 SystemClock.uptimeMillis() + " mNextWriteTime=" + 214 mNextWriteTime + " Callers=" + Debug.getCallers(4)); 215 notifyAll(); 216 } 217 218 yieldIfQueueTooDeep(); 219 } 220 221 Bitmap getThumbnail(String filename) { 222 synchronized (this) { 223 for (int queueNdx = mWriteQueue.size() - 1; queueNdx >= 0; --queueNdx) { 224 final WriteQueueItem item = mWriteQueue.get(queueNdx); 225 if (item instanceof ImageWriteQueueItem) { 226 ImageWriteQueueItem imageWriteQueueItem = (ImageWriteQueueItem) item; 227 if (imageWriteQueueItem.mFilename.equals(filename)) { 228 return imageWriteQueueItem.mImage; 229 } 230 } 231 } 232 return null; 233 } 234 } 235 236 private StringWriter saveToXml(TaskRecord task) throws IOException, XmlPullParserException { 237 if (DEBUG) Slog.d(TAG, "saveToXml: task=" + task); 238 final XmlSerializer xmlSerializer = new FastXmlSerializer(); 239 StringWriter stringWriter = new StringWriter(); 240 xmlSerializer.setOutput(stringWriter); 241 242 if (DEBUG) xmlSerializer.setFeature( 243 "http://xmlpull.org/v1/doc/features.html#indent-output", true); 244 245 // save task 246 xmlSerializer.startDocument(null, true); 247 248 xmlSerializer.startTag(null, TAG_TASK); 249 task.saveToXml(xmlSerializer); 250 xmlSerializer.endTag(null, TAG_TASK); 251 252 xmlSerializer.endDocument(); 253 xmlSerializer.flush(); 254 255 return stringWriter; 256 } 257 258 private String fileToString(File file) { 259 final String newline = System.lineSeparator(); 260 try { 261 BufferedReader reader = new BufferedReader(new FileReader(file)); 262 StringBuffer sb = new StringBuffer((int) file.length() * 2); 263 String line; 264 while ((line = reader.readLine()) != null) { 265 sb.append(line + newline); 266 } 267 reader.close(); 268 return sb.toString(); 269 } catch (IOException ioe) { 270 Slog.e(TAG, "Couldn't read file " + file.getName()); 271 return null; 272 } 273 } 274 275 private TaskRecord taskIdToTask(int taskId, ArrayList<TaskRecord> tasks) { 276 if (taskId < 0) { 277 return null; 278 } 279 for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) { 280 final TaskRecord task = tasks.get(taskNdx); 281 if (task.taskId == taskId) { 282 return task; 283 } 284 } 285 Slog.e(TAG, "Restore affiliation error looking for taskId=" + taskId); 286 return null; 287 } 288 289 ArrayList<TaskRecord> restoreTasksLocked() { 290 final ArrayList<TaskRecord> tasks = new ArrayList<TaskRecord>(); 291 ArraySet<Integer> recoveredTaskIds = new ArraySet<Integer>(); 292 293 File[] recentFiles = sTasksDir.listFiles(); 294 if (recentFiles == null) { 295 Slog.e(TAG, "Unable to list files from " + sTasksDir); 296 return tasks; 297 } 298 299 for (int taskNdx = 0; taskNdx < recentFiles.length; ++taskNdx) { 300 File taskFile = recentFiles[taskNdx]; 301 if (DEBUG) Slog.d(TAG, "restoreTasksLocked: taskFile=" + taskFile.getName()); 302 BufferedReader reader = null; 303 boolean deleteFile = false; 304 try { 305 reader = new BufferedReader(new FileReader(taskFile)); 306 final XmlPullParser in = Xml.newPullParser(); 307 in.setInput(reader); 308 309 int event; 310 while (((event = in.next()) != XmlPullParser.END_DOCUMENT) && 311 event != XmlPullParser.END_TAG) { 312 final String name = in.getName(); 313 if (event == XmlPullParser.START_TAG) { 314 if (DEBUG) Slog.d(TAG, "restoreTasksLocked: START_TAG name=" + name); 315 if (TAG_TASK.equals(name)) { 316 final TaskRecord task = 317 TaskRecord.restoreFromXml(in, mStackSupervisor); 318 if (DEBUG) Slog.d(TAG, "restoreTasksLocked: restored task=" + 319 task); 320 if (task != null) { 321 task.isPersistable = true; 322 // XXX Don't add to write queue... there is no reason to write 323 // out the stuff we just read, if we don't write it we will 324 // read the same thing again. 325 //mWriteQueue.add(new TaskWriteQueueItem(task)); 326 tasks.add(task); 327 final int taskId = task.taskId; 328 recoveredTaskIds.add(taskId); 329 mStackSupervisor.setNextTaskId(taskId); 330 } else { 331 Slog.e(TAG, "Unable to restore taskFile=" + taskFile + ": " + 332 fileToString(taskFile)); 333 } 334 } else { 335 Slog.wtf(TAG, "restoreTasksLocked Unknown xml event=" + event + 336 " name=" + name); 337 } 338 } 339 XmlUtils.skipCurrentTag(in); 340 } 341 } catch (Exception e) { 342 Slog.wtf(TAG, "Unable to parse " + taskFile + ". Error ", e); 343 Slog.e(TAG, "Failing file: " + fileToString(taskFile)); 344 deleteFile = true; 345 } finally { 346 if (reader != null) { 347 try { 348 reader.close(); 349 } catch (IOException e) { 350 } 351 } 352 if (!DEBUG && deleteFile) { 353 if (true || DEBUG) Slog.d(TAG, "Deleting file=" + taskFile.getName()); 354 taskFile.delete(); 355 } 356 } 357 } 358 359 if (!DEBUG) { 360 removeObsoleteFiles(recoveredTaskIds); 361 } 362 363 // Fixup task affiliation from taskIds 364 for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) { 365 final TaskRecord task = tasks.get(taskNdx); 366 task.setPrevAffiliate(taskIdToTask(task.mPrevAffiliateTaskId, tasks)); 367 task.setNextAffiliate(taskIdToTask(task.mNextAffiliateTaskId, tasks)); 368 } 369 370 TaskRecord[] tasksArray = new TaskRecord[tasks.size()]; 371 tasks.toArray(tasksArray); 372 Arrays.sort(tasksArray, new Comparator<TaskRecord>() { 373 @Override 374 public int compare(TaskRecord lhs, TaskRecord rhs) { 375 final long diff = rhs.mLastTimeMoved - lhs.mLastTimeMoved; 376 if (diff < 0) { 377 return -1; 378 } else if (diff > 0) { 379 return +1; 380 } else { 381 return 0; 382 } 383 } 384 }); 385 386 return new ArrayList<TaskRecord>(Arrays.asList(tasksArray)); 387 } 388 389 private static void removeObsoleteFiles(ArraySet<Integer> persistentTaskIds, File[] files) { 390 if (DEBUG) Slog.d(TAG, "removeObsoleteFile: persistentTaskIds=" + persistentTaskIds + 391 " files=" + files); 392 if (files == null) { 393 Slog.e(TAG, "File error accessing recents directory (too many files open?)."); 394 return; 395 } 396 for (int fileNdx = 0; fileNdx < files.length; ++fileNdx) { 397 File file = files[fileNdx]; 398 String filename = file.getName(); 399 final int taskIdEnd = filename.indexOf('_'); 400 if (taskIdEnd > 0) { 401 final int taskId; 402 try { 403 taskId = Integer.valueOf(filename.substring(0, taskIdEnd)); 404 if (DEBUG) Slog.d(TAG, "removeObsoleteFile: Found taskId=" + taskId); 405 } catch (Exception e) { 406 Slog.wtf(TAG, "removeObsoleteFile: Can't parse file=" + file.getName()); 407 file.delete(); 408 continue; 409 } 410 if (!persistentTaskIds.contains(taskId)) { 411 if (true || DEBUG) Slog.d(TAG, "removeObsoleteFile: deleting file=" + 412 file.getName()); 413 file.delete(); 414 } 415 } 416 } 417 } 418 419 private void removeObsoleteFiles(ArraySet<Integer> persistentTaskIds) { 420 removeObsoleteFiles(persistentTaskIds, sTasksDir.listFiles()); 421 removeObsoleteFiles(persistentTaskIds, sImagesDir.listFiles()); 422 } 423 424 static Bitmap restoreImage(String filename) { 425 if (DEBUG) Slog.d(TAG, "restoreImage: restoring " + filename); 426 return BitmapFactory.decodeFile(sImagesDir + File.separator + filename); 427 } 428 429 private class LazyTaskWriterThread extends Thread { 430 431 LazyTaskWriterThread(String name) { 432 super(name); 433 } 434 435 @Override 436 public void run() { 437 ArraySet<Integer> persistentTaskIds = new ArraySet<Integer>(); 438 while (true) { 439 // We can't lock mService while holding TaskPersister.this, but we don't want to 440 // call removeObsoleteFiles every time through the loop, only the last time before 441 // going to sleep. The risk is that we call removeObsoleteFiles() successively. 442 final boolean probablyDone; 443 synchronized (TaskPersister.this) { 444 probablyDone = mWriteQueue.isEmpty(); 445 } 446 if (probablyDone) { 447 if (DEBUG) Slog.d(TAG, "Looking for obsolete files."); 448 persistentTaskIds.clear(); 449 synchronized (mService) { 450 final ArrayList<TaskRecord> tasks = mService.mRecentTasks; 451 if (DEBUG) Slog.d(TAG, "mRecents=" + tasks); 452 for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) { 453 final TaskRecord task = tasks.get(taskNdx); 454 if (DEBUG) Slog.d(TAG, "LazyTaskWriter: task=" + task + " persistable=" + 455 task.isPersistable); 456 if (task.isPersistable && !task.stack.isHomeStack()) { 457 if (DEBUG) Slog.d(TAG, "adding to persistentTaskIds task=" + task); 458 persistentTaskIds.add(task.taskId); 459 } else { 460 if (DEBUG) Slog.d(TAG, "omitting from persistentTaskIds task=" + task); 461 } 462 } 463 } 464 removeObsoleteFiles(persistentTaskIds); 465 } 466 467 // If mNextWriteTime, then don't delay between each call to saveToXml(). 468 final WriteQueueItem item; 469 synchronized (TaskPersister.this) { 470 if (mNextWriteTime != FLUSH_QUEUE) { 471 // The next write we don't have to wait so long. 472 mNextWriteTime = SystemClock.uptimeMillis() + INTER_WRITE_DELAY_MS; 473 if (DEBUG) Slog.d(TAG, "Next write time may be in " + 474 INTER_WRITE_DELAY_MS + " msec. (" + mNextWriteTime + ")"); 475 } 476 477 while (mWriteQueue.isEmpty()) { 478 mNextWriteTime = 0; // idle. 479 try { 480 if (DEBUG) Slog.d(TAG, "LazyTaskWriter: waiting indefinitely."); 481 TaskPersister.this.wait(); 482 } catch (InterruptedException e) { 483 } 484 // Invariant: mNextWriteTime is either FLUSH_QUEUE or PRE_WRITE_DELAY_MS 485 // from now. 486 } 487 item = mWriteQueue.remove(0); 488 489 long now = SystemClock.uptimeMillis(); 490 if (DEBUG) Slog.d(TAG, "LazyTaskWriter: now=" + now + " mNextWriteTime=" + 491 mNextWriteTime + " mWriteQueue.size=" + mWriteQueue.size()); 492 while (now < mNextWriteTime) { 493 try { 494 if (DEBUG) Slog.d(TAG, "LazyTaskWriter: waiting " + 495 (mNextWriteTime - now)); 496 TaskPersister.this.wait(mNextWriteTime - now); 497 } catch (InterruptedException e) { 498 } 499 now = SystemClock.uptimeMillis(); 500 } 501 502 // Got something to do. 503 } 504 505 if (item instanceof ImageWriteQueueItem) { 506 ImageWriteQueueItem imageWriteQueueItem = (ImageWriteQueueItem) item; 507 final String filename = imageWriteQueueItem.mFilename; 508 final Bitmap bitmap = imageWriteQueueItem.mImage; 509 if (DEBUG) Slog.d(TAG, "writing bitmap: filename=" + filename); 510 FileOutputStream imageFile = null; 511 try { 512 imageFile = new FileOutputStream(new File(sImagesDir, filename)); 513 bitmap.compress(Bitmap.CompressFormat.PNG, 100, imageFile); 514 } catch (Exception e) { 515 Slog.e(TAG, "saveImage: unable to save " + filename, e); 516 } finally { 517 if (imageFile != null) { 518 try { 519 imageFile.close(); 520 } catch (IOException e) { 521 } 522 } 523 } 524 } else if (item instanceof TaskWriteQueueItem) { 525 // Write out one task. 526 StringWriter stringWriter = null; 527 TaskRecord task = ((TaskWriteQueueItem) item).mTask; 528 if (DEBUG) Slog.d(TAG, "Writing task=" + task); 529 synchronized (mService) { 530 if (task.inRecents) { 531 // Still there. 532 try { 533 if (DEBUG) Slog.d(TAG, "Saving task=" + task); 534 stringWriter = saveToXml(task); 535 } catch (IOException e) { 536 } catch (XmlPullParserException e) { 537 } 538 } 539 } 540 if (stringWriter != null) { 541 // Write out xml file while not holding mService lock. 542 FileOutputStream file = null; 543 AtomicFile atomicFile = null; 544 try { 545 atomicFile = new AtomicFile(new File(sTasksDir, String.valueOf( 546 task.taskId) + RECENTS_FILENAME + TASK_EXTENSION)); 547 file = atomicFile.startWrite(); 548 file.write(stringWriter.toString().getBytes()); 549 file.write('\n'); 550 atomicFile.finishWrite(file); 551 } catch (IOException e) { 552 if (file != null) { 553 atomicFile.failWrite(file); 554 } 555 Slog.e(TAG, "Unable to open " + atomicFile + " for persisting. " + 556 e); 557 } 558 } 559 } 560 } 561 } 562 } 563} 564