FusedPrintersProvider.java revision a798c0a984f29f7180883a61839f68d2cbf0c6ce
1/* 2 * Copyright (C) 2013 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.printspooler.ui; 18 19import android.content.ComponentName; 20import android.content.Context; 21import android.content.Loader; 22import android.content.pm.ServiceInfo; 23import android.os.AsyncTask; 24import android.print.PrintManager; 25import android.print.PrinterDiscoverySession; 26import android.print.PrinterDiscoverySession.OnPrintersChangeListener; 27import android.print.PrinterId; 28import android.print.PrinterInfo; 29import android.printservice.PrintServiceInfo; 30import android.util.ArrayMap; 31import android.util.ArraySet; 32import android.util.AtomicFile; 33import android.util.Log; 34import android.util.Slog; 35import android.util.Xml; 36 37import com.android.internal.util.FastXmlSerializer; 38 39import org.xmlpull.v1.XmlPullParser; 40import org.xmlpull.v1.XmlPullParserException; 41import org.xmlpull.v1.XmlSerializer; 42 43import java.io.File; 44import java.io.FileInputStream; 45import java.io.FileNotFoundException; 46import java.io.FileOutputStream; 47import java.io.IOException; 48import java.util.ArrayList; 49import java.util.Collections; 50import java.util.List; 51import java.util.Map; 52import java.util.Set; 53 54import libcore.io.IoUtils; 55 56/** 57 * This class is responsible for loading printers by doing discovery 58 * and merging the discovered printers with the previously used ones. 59 */ 60public final class FusedPrintersProvider extends Loader<List<PrinterInfo>> { 61 private static final String LOG_TAG = "FusedPrintersProvider"; 62 63 private static final boolean DEBUG = false; 64 65 private static final double WEIGHT_DECAY_COEFFICIENT = 0.95f; 66 private static final int MAX_HISTORY_LENGTH = 50; 67 68 private static final int MAX_FAVORITE_PRINTER_COUNT = 4; 69 70 private final List<PrinterInfo> mPrinters = 71 new ArrayList<PrinterInfo>(); 72 73 private final List<PrinterInfo> mFavoritePrinters = 74 new ArrayList<PrinterInfo>(); 75 76 private final PersistenceManager mPersistenceManager; 77 78 private PrinterDiscoverySession mDiscoverySession; 79 80 private PrinterId mTrackedPrinter; 81 82 private boolean mPrintersUpdatedBefore; 83 84 public FusedPrintersProvider(Context context) { 85 super(context); 86 mPersistenceManager = new PersistenceManager(context); 87 } 88 89 public void addHistoricalPrinter(PrinterInfo printer) { 90 mPersistenceManager.addPrinterAndWritePrinterHistory(printer); 91 } 92 93 private void computeAndDeliverResult(ArrayMap<PrinterId, PrinterInfo> discoveredPrinters, 94 ArrayMap<PrinterId, PrinterInfo> favoritePrinters) { 95 List<PrinterInfo> printers = new ArrayList<PrinterInfo>(); 96 97 // Add the updated favorite printers. 98 final int favoritePrinterCount = favoritePrinters.size(); 99 for (int i = 0; i < favoritePrinterCount; i++) { 100 PrinterInfo favoritePrinter = favoritePrinters.valueAt(i); 101 PrinterInfo updatedPrinter = discoveredPrinters.remove( 102 favoritePrinter.getId()); 103 if (updatedPrinter != null) { 104 printers.add(updatedPrinter); 105 } else { 106 printers.add(favoritePrinter); 107 } 108 } 109 110 // Add other updated printers. 111 final int printerCount = mPrinters.size(); 112 for (int i = 0; i < printerCount; i++) { 113 PrinterInfo printer = mPrinters.get(i); 114 PrinterInfo updatedPrinter = discoveredPrinters.remove( 115 printer.getId()); 116 if (updatedPrinter != null) { 117 printers.add(updatedPrinter); 118 } 119 } 120 121 // Add the new printers, i.e. what is left. 122 printers.addAll(discoveredPrinters.values()); 123 124 // Update the list of printers. 125 mPrinters.clear(); 126 mPrinters.addAll(printers); 127 128 if (isStarted()) { 129 // If stated deliver the new printers. 130 deliverResult(printers); 131 } else { 132 // Otherwise, take a note for the change. 133 onContentChanged(); 134 } 135 } 136 137 @Override 138 protected void onStartLoading() { 139 if (DEBUG) { 140 Log.i(LOG_TAG, "onStartLoading() " + FusedPrintersProvider.this.hashCode()); 141 } 142 // The contract is that if we already have a valid, 143 // result the we have to deliver it immediately. 144 if (!mPrinters.isEmpty()) { 145 deliverResult(new ArrayList<PrinterInfo>(mPrinters)); 146 } 147 // Always load the data to ensure discovery period is 148 // started and to make sure obsolete printers are updated. 149 onForceLoad(); 150 } 151 152 @Override 153 protected void onStopLoading() { 154 if (DEBUG) { 155 Log.i(LOG_TAG, "onStopLoading() " + FusedPrintersProvider.this.hashCode()); 156 } 157 onCancelLoad(); 158 } 159 160 @Override 161 protected void onForceLoad() { 162 if (DEBUG) { 163 Log.i(LOG_TAG, "onForceLoad() " + FusedPrintersProvider.this.hashCode()); 164 } 165 loadInternal(); 166 } 167 168 private void loadInternal() { 169 if (mDiscoverySession == null) { 170 PrintManager printManager = (PrintManager) getContext() 171 .getSystemService(Context.PRINT_SERVICE); 172 mDiscoverySession = printManager.createPrinterDiscoverySession(); 173 mPersistenceManager.readPrinterHistory(); 174 } else if (mPersistenceManager.isHistoryChanged()) { 175 mPersistenceManager.readPrinterHistory(); 176 } 177 if (mPersistenceManager.isReadHistoryCompleted() 178 && !mDiscoverySession.isPrinterDiscoveryStarted()) { 179 mDiscoverySession.setOnPrintersChangeListener(new OnPrintersChangeListener() { 180 @Override 181 public void onPrintersChanged() { 182 if (DEBUG) { 183 Log.i(LOG_TAG, "onPrintersChanged() count:" 184 + mDiscoverySession.getPrinters().size() 185 + " " + FusedPrintersProvider.this.hashCode()); 186 } 187 updatePrinters(mDiscoverySession.getPrinters(), mFavoritePrinters); 188 } 189 }); 190 final int favoriteCount = mFavoritePrinters.size(); 191 List<PrinterId> printerIds = new ArrayList<PrinterId>(favoriteCount); 192 for (int i = 0; i < favoriteCount; i++) { 193 printerIds.add(mFavoritePrinters.get(i).getId()); 194 } 195 mDiscoverySession.startPrinterDiscovery(printerIds); 196 List<PrinterInfo> printers = mDiscoverySession.getPrinters(); 197 if (!printers.isEmpty()) { 198 updatePrinters(printers, mFavoritePrinters); 199 } 200 } 201 } 202 203 private void updatePrinters(List<PrinterInfo> printers, List<PrinterInfo> favoritePrinters) { 204 if (mPrintersUpdatedBefore && mPrinters.equals(printers) 205 && mFavoritePrinters.equals(favoritePrinters)) { 206 return; 207 } 208 209 mPrintersUpdatedBefore = true; 210 211 ArrayMap<PrinterId, PrinterInfo> printersMap = 212 new ArrayMap<PrinterId, PrinterInfo>(); 213 final int printerCount = printers.size(); 214 for (int i = 0; i < printerCount; i++) { 215 PrinterInfo printer = printers.get(i); 216 printersMap.put(printer.getId(), printer); 217 } 218 219 ArrayMap<PrinterId, PrinterInfo> favoritePrintersMap = 220 new ArrayMap<PrinterId, PrinterInfo>(); 221 final int favoritePrinterCount = favoritePrinters.size(); 222 for (int i = 0; i < favoritePrinterCount; i++) { 223 PrinterInfo favoritePrinter = favoritePrinters.get(i); 224 favoritePrintersMap.put(favoritePrinter.getId(), favoritePrinter); 225 } 226 227 computeAndDeliverResult(printersMap, favoritePrintersMap); 228 } 229 230 @Override 231 protected boolean onCancelLoad() { 232 if (DEBUG) { 233 Log.i(LOG_TAG, "onCancelLoad() " + FusedPrintersProvider.this.hashCode()); 234 } 235 return cancelInternal(); 236 } 237 238 private boolean cancelInternal() { 239 if (mDiscoverySession != null 240 && mDiscoverySession.isPrinterDiscoveryStarted()) { 241 if (mTrackedPrinter != null) { 242 mDiscoverySession.stopPrinterStateTracking(mTrackedPrinter); 243 mTrackedPrinter = null; 244 } 245 mDiscoverySession.stopPrinterDiscovery(); 246 return true; 247 } else if (mPersistenceManager.isReadHistoryInProgress()) { 248 return mPersistenceManager.stopReadPrinterHistory(); 249 } 250 return false; 251 } 252 253 @Override 254 protected void onReset() { 255 if (DEBUG) { 256 Log.i(LOG_TAG, "onReset() " + FusedPrintersProvider.this.hashCode()); 257 } 258 onStopLoading(); 259 mPrinters.clear(); 260 if (mDiscoverySession != null) { 261 mDiscoverySession.destroy(); 262 mDiscoverySession = null; 263 } 264 } 265 266 @Override 267 protected void onAbandon() { 268 if (DEBUG) { 269 Log.i(LOG_TAG, "onAbandon() " + FusedPrintersProvider.this.hashCode()); 270 } 271 onStopLoading(); 272 } 273 274 public void setTrackedPrinter(PrinterId printerId) { 275 if (isStarted() && mDiscoverySession != null 276 && mDiscoverySession.isPrinterDiscoveryStarted()) { 277 if (mTrackedPrinter != null) { 278 if (mTrackedPrinter.equals(printerId)) { 279 return; 280 } 281 mDiscoverySession.stopPrinterStateTracking(mTrackedPrinter); 282 } 283 mTrackedPrinter = printerId; 284 if (printerId != null) { 285 mDiscoverySession.startPrinterStateTracking(printerId); 286 } 287 } 288 } 289 290 public boolean isFavoritePrinter(PrinterId printerId) { 291 final int printerCount = mFavoritePrinters.size(); 292 for (int i = 0; i < printerCount; i++) { 293 PrinterInfo favoritePritner = mFavoritePrinters.get(i); 294 if (favoritePritner.getId().equals(printerId)) { 295 return true; 296 } 297 } 298 return false; 299 } 300 301 public void forgetFavoritePrinter(PrinterId printerId) { 302 List<PrinterInfo> newFavoritePrinters = null; 303 304 // Remove the printer from the favorites. 305 final int favoritePrinterCount = mFavoritePrinters.size(); 306 for (int i = 0; i < favoritePrinterCount; i++) { 307 PrinterInfo favoritePrinter = mFavoritePrinters.get(i); 308 if (favoritePrinter.getId().equals(printerId)) { 309 newFavoritePrinters = new ArrayList<PrinterInfo>(); 310 newFavoritePrinters.addAll(mPrinters); 311 newFavoritePrinters.remove(i); 312 break; 313 } 314 } 315 316 // If we removed a favorite printer, we have work to do. 317 if (newFavoritePrinters != null) { 318 // Remove the printer from history and persist the latter. 319 mPersistenceManager.removeHistoricalPrinterAndWritePrinterHistory(printerId); 320 321 // Recompute and deliver the printers. 322 updatePrinters(mDiscoverySession.getPrinters(), newFavoritePrinters); 323 } 324 } 325 326 private final class PersistenceManager { 327 private static final String PERSIST_FILE_NAME = "printer_history.xml"; 328 329 private static final String TAG_PRINTERS = "printers"; 330 331 private static final String TAG_PRINTER = "printer"; 332 private static final String TAG_PRINTER_ID = "printerId"; 333 334 private static final String ATTR_LOCAL_ID = "localId"; 335 private static final String ATTR_SERVICE_NAME = "serviceName"; 336 337 private static final String ATTR_NAME = "name"; 338 private static final String ATTR_DESCRIPTION = "description"; 339 private static final String ATTR_STATUS = "status"; 340 341 private final AtomicFile mStatePersistFile; 342 343 private List<PrinterInfo> mHistoricalPrinters = new ArrayList<PrinterInfo>(); 344 345 private boolean mReadHistoryCompleted; 346 private boolean mReadHistoryInProgress; 347 348 private ReadTask mReadTask; 349 350 private volatile long mLastReadHistoryTimestamp; 351 352 private PersistenceManager(Context context) { 353 mStatePersistFile = new AtomicFile(new File(context.getFilesDir(), 354 PERSIST_FILE_NAME)); 355 } 356 357 public boolean isReadHistoryInProgress() { 358 return mReadHistoryInProgress; 359 } 360 361 public boolean isReadHistoryCompleted() { 362 return mReadHistoryCompleted; 363 } 364 365 public boolean stopReadPrinterHistory() { 366 final boolean cancelled = mReadTask.cancel(true); 367 mReadTask = null; 368 return cancelled; 369 } 370 371 public void readPrinterHistory() { 372 if (DEBUG) { 373 Log.i(LOG_TAG, "read history started " 374 + FusedPrintersProvider.this.hashCode()); 375 } 376 mReadHistoryInProgress = true; 377 mReadTask = new ReadTask(); 378 mReadTask.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, (Void[]) null); 379 } 380 381 @SuppressWarnings("unchecked") 382 public void addPrinterAndWritePrinterHistory(PrinterInfo printer) { 383 if (mHistoricalPrinters.size() >= MAX_HISTORY_LENGTH) { 384 mHistoricalPrinters.remove(0); 385 } 386 mHistoricalPrinters.add(printer); 387 new WriteTask().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, 388 new ArrayList<PrinterInfo>(mHistoricalPrinters)); 389 } 390 391 @SuppressWarnings("unchecked") 392 public void removeHistoricalPrinterAndWritePrinterHistory(PrinterId printerId) { 393 boolean writeHistory = false; 394 final int printerCount = mHistoricalPrinters.size(); 395 for (int i = printerCount - 1; i >= 0; i--) { 396 PrinterInfo historicalPrinter = mHistoricalPrinters.get(i); 397 if (historicalPrinter.getId().equals(printerId)) { 398 mHistoricalPrinters.remove(i); 399 writeHistory = true; 400 } 401 } 402 if (writeHistory) { 403 new WriteTask().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, 404 new ArrayList<PrinterInfo>(mHistoricalPrinters)); 405 } 406 } 407 408 public boolean isHistoryChanged() { 409 return mLastReadHistoryTimestamp != mStatePersistFile.getBaseFile().lastModified(); 410 } 411 412 private List<PrinterInfo> computeFavoritePrinters(List<PrinterInfo> printers) { 413 Map<PrinterId, PrinterRecord> recordMap = 414 new ArrayMap<PrinterId, PrinterRecord>(); 415 416 // Recompute the weights. 417 float currentWeight = 1.0f; 418 final int printerCount = printers.size(); 419 for (int i = printerCount - 1; i >= 0; i--) { 420 PrinterInfo printer = printers.get(i); 421 // Aggregate weight for the same printer 422 PrinterRecord record = recordMap.get(printer.getId()); 423 if (record == null) { 424 record = new PrinterRecord(printer); 425 recordMap.put(printer.getId(), record); 426 } 427 record.weight += currentWeight; 428 currentWeight *= WEIGHT_DECAY_COEFFICIENT; 429 } 430 431 // Soft the favorite printers. 432 List<PrinterRecord> favoriteRecords = new ArrayList<PrinterRecord>( 433 recordMap.values()); 434 Collections.sort(favoriteRecords); 435 436 // Write the favorites to the output. 437 final int favoriteCount = Math.min(favoriteRecords.size(), 438 MAX_FAVORITE_PRINTER_COUNT); 439 List<PrinterInfo> favoritePrinters = new ArrayList<PrinterInfo>(favoriteCount); 440 for (int i = 0; i < favoriteCount; i++) { 441 PrinterInfo printer = favoriteRecords.get(i).printer; 442 favoritePrinters.add(printer); 443 } 444 445 return favoritePrinters; 446 } 447 448 private final class PrinterRecord implements Comparable<PrinterRecord> { 449 public final PrinterInfo printer; 450 public float weight; 451 452 public PrinterRecord(PrinterInfo printer) { 453 this.printer = printer; 454 } 455 456 @Override 457 public int compareTo(PrinterRecord another) { 458 return Float.floatToIntBits(another.weight) - Float.floatToIntBits(weight); 459 } 460 } 461 462 private final class ReadTask extends AsyncTask<Void, Void, List<PrinterInfo>> { 463 @Override 464 protected List<PrinterInfo> doInBackground(Void... args) { 465 return doReadPrinterHistory(); 466 } 467 468 @Override 469 protected void onPostExecute(List<PrinterInfo> printers) { 470 if (DEBUG) { 471 Log.i(LOG_TAG, "read history completed " 472 + FusedPrintersProvider.this.hashCode()); 473 } 474 475 // Ignore printer records whose target services are not enabled. 476 PrintManager printManager = (PrintManager) getContext() 477 .getSystemService(Context.PRINT_SERVICE); 478 List<PrintServiceInfo> services = printManager 479 .getEnabledPrintServices(); 480 481 Set<ComponentName> enabledComponents = new ArraySet<ComponentName>(); 482 final int installedServiceCount = services.size(); 483 for (int i = 0; i < installedServiceCount; i++) { 484 ServiceInfo serviceInfo = services.get(i).getResolveInfo().serviceInfo; 485 ComponentName componentName = new ComponentName( 486 serviceInfo.packageName, serviceInfo.name); 487 enabledComponents.add(componentName); 488 } 489 490 final int printerCount = printers.size(); 491 for (int i = printerCount - 1; i >= 0; i--) { 492 ComponentName printerServiceName = printers.get(i).getId().getServiceName(); 493 if (!enabledComponents.contains(printerServiceName)) { 494 printers.remove(i); 495 } 496 } 497 498 // Store the filtered list. 499 mHistoricalPrinters = printers; 500 501 // Compute the favorite printers. 502 mFavoritePrinters.clear(); 503 mFavoritePrinters.addAll(computeFavoritePrinters(mHistoricalPrinters)); 504 505 mReadHistoryInProgress = false; 506 mReadHistoryCompleted = true; 507 508 // Deliver the printers. 509 updatePrinters(mDiscoverySession.getPrinters(), mHistoricalPrinters); 510 511 // Loading the available printers if needed. 512 loadInternal(); 513 514 // We are done. 515 mReadTask = null; 516 } 517 518 private List<PrinterInfo> doReadPrinterHistory() { 519 final FileInputStream in; 520 try { 521 in = mStatePersistFile.openRead(); 522 } catch (FileNotFoundException fnfe) { 523 if (DEBUG) { 524 Log.i(LOG_TAG, "No existing printer history " 525 + FusedPrintersProvider.this.hashCode()); 526 } 527 return new ArrayList<PrinterInfo>(); 528 } 529 try { 530 List<PrinterInfo> printers = new ArrayList<PrinterInfo>(); 531 XmlPullParser parser = Xml.newPullParser(); 532 parser.setInput(in, null); 533 parseState(parser, printers); 534 // Take a note which version of the history was read. 535 mLastReadHistoryTimestamp = mStatePersistFile.getBaseFile().lastModified(); 536 return printers; 537 } catch (IllegalStateException ise) { 538 Slog.w(LOG_TAG, "Failed parsing ", ise); 539 } catch (NullPointerException npe) { 540 Slog.w(LOG_TAG, "Failed parsing ", npe); 541 } catch (NumberFormatException nfe) { 542 Slog.w(LOG_TAG, "Failed parsing ", nfe); 543 } catch (XmlPullParserException xppe) { 544 Slog.w(LOG_TAG, "Failed parsing ", xppe); 545 } catch (IOException ioe) { 546 Slog.w(LOG_TAG, "Failed parsing ", ioe); 547 } catch (IndexOutOfBoundsException iobe) { 548 Slog.w(LOG_TAG, "Failed parsing ", iobe); 549 } finally { 550 IoUtils.closeQuietly(in); 551 } 552 553 return Collections.emptyList(); 554 } 555 556 private void parseState(XmlPullParser parser, List<PrinterInfo> outPrinters) 557 throws IOException, XmlPullParserException { 558 parser.next(); 559 skipEmptyTextTags(parser); 560 expect(parser, XmlPullParser.START_TAG, TAG_PRINTERS); 561 parser.next(); 562 563 while (parsePrinter(parser, outPrinters)) { 564 // Be nice and respond to cancellation 565 if (isCancelled()) { 566 return; 567 } 568 parser.next(); 569 } 570 571 skipEmptyTextTags(parser); 572 expect(parser, XmlPullParser.END_TAG, TAG_PRINTERS); 573 } 574 575 private boolean parsePrinter(XmlPullParser parser, List<PrinterInfo> outPrinters) 576 throws IOException, XmlPullParserException { 577 skipEmptyTextTags(parser); 578 if (!accept(parser, XmlPullParser.START_TAG, TAG_PRINTER)) { 579 return false; 580 } 581 582 String name = parser.getAttributeValue(null, ATTR_NAME); 583 String description = parser.getAttributeValue(null, ATTR_DESCRIPTION); 584 final int status = Integer.parseInt(parser.getAttributeValue(null, ATTR_STATUS)); 585 586 parser.next(); 587 588 skipEmptyTextTags(parser); 589 expect(parser, XmlPullParser.START_TAG, TAG_PRINTER_ID); 590 String localId = parser.getAttributeValue(null, ATTR_LOCAL_ID); 591 ComponentName service = ComponentName.unflattenFromString(parser.getAttributeValue( 592 null, ATTR_SERVICE_NAME)); 593 PrinterId printerId = new PrinterId(service, localId); 594 parser.next(); 595 skipEmptyTextTags(parser); 596 expect(parser, XmlPullParser.END_TAG, TAG_PRINTER_ID); 597 parser.next(); 598 599 PrinterInfo.Builder builder = new PrinterInfo.Builder(printerId, name, status); 600 builder.setDescription(description); 601 PrinterInfo printer = builder.build(); 602 603 outPrinters.add(printer); 604 605 if (DEBUG) { 606 Log.i(LOG_TAG, "[RESTORED] " + printer); 607 } 608 609 skipEmptyTextTags(parser); 610 expect(parser, XmlPullParser.END_TAG, TAG_PRINTER); 611 612 return true; 613 } 614 615 private void expect(XmlPullParser parser, int type, String tag) 616 throws IOException, XmlPullParserException { 617 if (!accept(parser, type, tag)) { 618 throw new XmlPullParserException("Exepected event: " + type 619 + " and tag: " + tag + " but got event: " + parser.getEventType() 620 + " and tag:" + parser.getName()); 621 } 622 } 623 624 private void skipEmptyTextTags(XmlPullParser parser) 625 throws IOException, XmlPullParserException { 626 while (accept(parser, XmlPullParser.TEXT, null) 627 && "\n".equals(parser.getText())) { 628 parser.next(); 629 } 630 } 631 632 private boolean accept(XmlPullParser parser, int type, String tag) 633 throws IOException, XmlPullParserException { 634 if (parser.getEventType() != type) { 635 return false; 636 } 637 if (tag != null) { 638 if (!tag.equals(parser.getName())) { 639 return false; 640 } 641 } else if (parser.getName() != null) { 642 return false; 643 } 644 return true; 645 } 646 } 647 648 private final class WriteTask extends AsyncTask<List<PrinterInfo>, Void, Void> { 649 @Override 650 protected Void doInBackground(List<PrinterInfo>... printers) { 651 doWritePrinterHistory(printers[0]); 652 return null; 653 } 654 655 private void doWritePrinterHistory(List<PrinterInfo> printers) { 656 FileOutputStream out = null; 657 try { 658 out = mStatePersistFile.startWrite(); 659 660 XmlSerializer serializer = new FastXmlSerializer(); 661 serializer.setOutput(out, "utf-8"); 662 serializer.startDocument(null, true); 663 serializer.startTag(null, TAG_PRINTERS); 664 665 final int printerCount = printers.size(); 666 for (int i = 0; i < printerCount; i++) { 667 PrinterInfo printer = printers.get(i); 668 669 serializer.startTag(null, TAG_PRINTER); 670 671 serializer.attribute(null, ATTR_NAME, printer.getName()); 672 // Historical printers are always stored as unavailable. 673 serializer.attribute(null, ATTR_STATUS, String.valueOf( 674 PrinterInfo.STATUS_UNAVAILABLE)); 675 String description = printer.getDescription(); 676 if (description != null) { 677 serializer.attribute(null, ATTR_DESCRIPTION, description); 678 } 679 680 PrinterId printerId = printer.getId(); 681 serializer.startTag(null, TAG_PRINTER_ID); 682 serializer.attribute(null, ATTR_LOCAL_ID, printerId.getLocalId()); 683 serializer.attribute(null, ATTR_SERVICE_NAME, printerId.getServiceName() 684 .flattenToString()); 685 serializer.endTag(null, TAG_PRINTER_ID); 686 687 serializer.endTag(null, TAG_PRINTER); 688 689 if (DEBUG) { 690 Log.i(LOG_TAG, "[PERSISTED] " + printer); 691 } 692 } 693 694 serializer.endTag(null, TAG_PRINTERS); 695 serializer.endDocument(); 696 mStatePersistFile.finishWrite(out); 697 698 if (DEBUG) { 699 Log.i(LOG_TAG, "[PERSIST END]"); 700 } 701 } catch (IOException ioe) { 702 Slog.w(LOG_TAG, "Failed to write printer history, restoring backup.", ioe); 703 mStatePersistFile.failWrite(out); 704 } finally { 705 IoUtils.closeQuietly(out); 706 } 707 } 708 } 709 } 710} 711