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 17 package com.android.printspooler; 18 19 import android.content.ComponentName; 20 import android.content.Context; 21 import android.content.Loader; 22 import android.content.pm.ServiceInfo; 23 import android.os.AsyncTask; 24 import android.print.PrintManager; 25 import android.print.PrinterDiscoverySession; 26 import android.print.PrinterDiscoverySession.OnPrintersChangeListener; 27 import android.print.PrinterId; 28 import android.print.PrinterInfo; 29 import android.printservice.PrintServiceInfo; 30 import android.util.ArrayMap; 31 import android.util.ArraySet; 32 import android.util.AtomicFile; 33 import android.util.Log; 34 import android.util.Slog; 35 import android.util.Xml; 36 37 import com.android.internal.util.FastXmlSerializer; 38 39 import org.xmlpull.v1.XmlPullParser; 40 import org.xmlpull.v1.XmlPullParserException; 41 import org.xmlpull.v1.XmlSerializer; 42 43 import java.io.File; 44 import java.io.FileInputStream; 45 import java.io.FileNotFoundException; 46 import java.io.FileOutputStream; 47 import java.io.IOException; 48 import java.util.ArrayList; 49 import java.util.Collections; 50 import java.util.List; 51 import java.util.Map; 52 import java.util.Set; 53 54 import 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 */ 60 public 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.startPrinterDisovery(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 mDiscoverySession.startPrinterStateTracking(printerId); 285 } 286 } 287 288 public boolean isFavoritePrinter(PrinterId printerId) { 289 final int printerCount = mFavoritePrinters.size(); 290 for (int i = 0; i < printerCount; i++) { 291 PrinterInfo favoritePritner = mFavoritePrinters.get(i); 292 if (favoritePritner.getId().equals(printerId)) { 293 return true; 294 } 295 } 296 return false; 297 } 298 299 public void forgetFavoritePrinter(PrinterId printerId) { 300 List<PrinterInfo> newFavoritePrinters = null; 301 302 // Remove the printer from the favorites. 303 final int favoritePrinterCount = mFavoritePrinters.size(); 304 for (int i = 0; i < favoritePrinterCount; i++) { 305 PrinterInfo favoritePrinter = mFavoritePrinters.get(i); 306 if (favoritePrinter.getId().equals(printerId)) { 307 newFavoritePrinters = new ArrayList<PrinterInfo>(); 308 newFavoritePrinters.addAll(mPrinters); 309 newFavoritePrinters.remove(i); 310 break; 311 } 312 } 313 314 // If we removed a favorite printer, we have work to do. 315 if (newFavoritePrinters != null) { 316 // Remove the printer from history and persist the latter. 317 mPersistenceManager.removeHistoricalPrinterAndWritePrinterHistory(printerId); 318 319 // Recompute and deliver the printers. 320 updatePrinters(mDiscoverySession.getPrinters(), newFavoritePrinters); 321 } 322 } 323 324 private final class PersistenceManager { 325 private static final String PERSIST_FILE_NAME = "printer_history.xml"; 326 327 private static final String TAG_PRINTERS = "printers"; 328 329 private static final String TAG_PRINTER = "printer"; 330 private static final String TAG_PRINTER_ID = "printerId"; 331 332 private static final String ATTR_LOCAL_ID = "localId"; 333 private static final String ATTR_SERVICE_NAME = "serviceName"; 334 335 private static final String ATTR_NAME = "name"; 336 private static final String ATTR_DESCRIPTION = "description"; 337 private static final String ATTR_STATUS = "status"; 338 339 private final AtomicFile mStatePersistFile; 340 341 private List<PrinterInfo> mHistoricalPrinters = new ArrayList<PrinterInfo>(); 342 343 private boolean mReadHistoryCompleted; 344 private boolean mReadHistoryInProgress; 345 346 private ReadTask mReadTask; 347 348 private volatile long mLastReadHistoryTimestamp; 349 350 private PersistenceManager(Context context) { 351 mStatePersistFile = new AtomicFile(new File(context.getFilesDir(), 352 PERSIST_FILE_NAME)); 353 } 354 355 public boolean isReadHistoryInProgress() { 356 return mReadHistoryInProgress; 357 } 358 359 public boolean isReadHistoryCompleted() { 360 return mReadHistoryCompleted; 361 } 362 363 public boolean stopReadPrinterHistory() { 364 final boolean cancelled = mReadTask.cancel(true); 365 mReadTask = null; 366 return cancelled; 367 } 368 369 public void readPrinterHistory() { 370 if (DEBUG) { 371 Log.i(LOG_TAG, "read history started " 372 + FusedPrintersProvider.this.hashCode()); 373 } 374 mReadHistoryInProgress = true; 375 mReadTask = new ReadTask(); 376 mReadTask.executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, (Void[]) null); 377 } 378 379 @SuppressWarnings("unchecked") 380 public void addPrinterAndWritePrinterHistory(PrinterInfo printer) { 381 if (mHistoricalPrinters.size() >= MAX_HISTORY_LENGTH) { 382 mHistoricalPrinters.remove(0); 383 } 384 mHistoricalPrinters.add(printer); 385 new WriteTask().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, 386 new ArrayList<PrinterInfo>(mHistoricalPrinters)); 387 } 388 389 @SuppressWarnings("unchecked") 390 public void removeHistoricalPrinterAndWritePrinterHistory(PrinterId printerId) { 391 boolean writeHistory = false; 392 final int printerCount = mHistoricalPrinters.size(); 393 for (int i = printerCount - 1; i >= 0; i--) { 394 PrinterInfo historicalPrinter = mHistoricalPrinters.get(i); 395 if (historicalPrinter.getId().equals(printerId)) { 396 mHistoricalPrinters.remove(i); 397 writeHistory = true; 398 } 399 } 400 if (writeHistory) { 401 new WriteTask().executeOnExecutor(AsyncTask.SERIAL_EXECUTOR, 402 new ArrayList<PrinterInfo>(mHistoricalPrinters)); 403 } 404 } 405 406 public boolean isHistoryChanged() { 407 return mLastReadHistoryTimestamp != mStatePersistFile.getBaseFile().lastModified(); 408 } 409 410 private List<PrinterInfo> computeFavoritePrinters(List<PrinterInfo> printers) { 411 Map<PrinterId, PrinterRecord> recordMap = 412 new ArrayMap<PrinterId, PrinterRecord>(); 413 414 // Recompute the weights. 415 float currentWeight = 1.0f; 416 final int printerCount = printers.size(); 417 for (int i = printerCount - 1; i >= 0; i--) { 418 PrinterInfo printer = printers.get(i); 419 // Aggregate weight for the same printer 420 PrinterRecord record = recordMap.get(printer.getId()); 421 if (record == null) { 422 record = new PrinterRecord(printer); 423 recordMap.put(printer.getId(), record); 424 } 425 record.weight += currentWeight; 426 currentWeight *= WEIGHT_DECAY_COEFFICIENT; 427 } 428 429 // Soft the favorite printers. 430 List<PrinterRecord> favoriteRecords = new ArrayList<PrinterRecord>( 431 recordMap.values()); 432 Collections.sort(favoriteRecords); 433 434 // Write the favorites to the output. 435 final int favoriteCount = Math.min(favoriteRecords.size(), 436 MAX_FAVORITE_PRINTER_COUNT); 437 List<PrinterInfo> favoritePrinters = new ArrayList<PrinterInfo>(favoriteCount); 438 for (int i = 0; i < favoriteCount; i++) { 439 PrinterInfo printer = favoriteRecords.get(i).printer; 440 favoritePrinters.add(printer); 441 } 442 443 return favoritePrinters; 444 } 445 446 private final class PrinterRecord implements Comparable<PrinterRecord> { 447 public final PrinterInfo printer; 448 public float weight; 449 450 public PrinterRecord(PrinterInfo printer) { 451 this.printer = printer; 452 } 453 454 @Override 455 public int compareTo(PrinterRecord another) { 456 return Float.floatToIntBits(another.weight) - Float.floatToIntBits(weight); 457 } 458 } 459 460 private final class ReadTask extends AsyncTask<Void, Void, List<PrinterInfo>> { 461 @Override 462 protected List<PrinterInfo> doInBackground(Void... args) { 463 return doReadPrinterHistory(); 464 } 465 466 @Override 467 protected void onPostExecute(List<PrinterInfo> printers) { 468 if (DEBUG) { 469 Log.i(LOG_TAG, "read history completed " 470 + FusedPrintersProvider.this.hashCode()); 471 } 472 473 // Ignore printer records whose target services are not enabled. 474 PrintManager printManager = (PrintManager) getContext() 475 .getSystemService(Context.PRINT_SERVICE); 476 List<PrintServiceInfo> services = printManager 477 .getEnabledPrintServices(); 478 479 Set<ComponentName> enabledComponents = new ArraySet<ComponentName>(); 480 final int installedServiceCount = services.size(); 481 for (int i = 0; i < installedServiceCount; i++) { 482 ServiceInfo serviceInfo = services.get(i).getResolveInfo().serviceInfo; 483 ComponentName componentName = new ComponentName( 484 serviceInfo.packageName, serviceInfo.name); 485 enabledComponents.add(componentName); 486 } 487 488 final int printerCount = printers.size(); 489 for (int i = printerCount - 1; i >= 0; i--) { 490 ComponentName printerServiceName = printers.get(i).getId().getServiceName(); 491 if (!enabledComponents.contains(printerServiceName)) { 492 printers.remove(i); 493 } 494 } 495 496 // Store the filtered list. 497 mHistoricalPrinters = printers; 498 499 // Compute the favorite printers. 500 mFavoritePrinters.clear(); 501 mFavoritePrinters.addAll(computeFavoritePrinters(mHistoricalPrinters)); 502 503 mReadHistoryInProgress = false; 504 mReadHistoryCompleted = true; 505 506 // Deliver the printers. 507 updatePrinters(mDiscoverySession.getPrinters(), mHistoricalPrinters); 508 509 // Loading the available printers if needed. 510 loadInternal(); 511 512 // We are done. 513 mReadTask = null; 514 } 515 516 private List<PrinterInfo> doReadPrinterHistory() { 517 FileInputStream in = null; 518 try { 519 in = mStatePersistFile.openRead(); 520 } catch (FileNotFoundException fnfe) { 521 if (DEBUG) { 522 Log.i(LOG_TAG, "No existing printer history " 523 + FusedPrintersProvider.this.hashCode()); 524 } 525 return new ArrayList<PrinterInfo>(); 526 } 527 try { 528 List<PrinterInfo> printers = new ArrayList<PrinterInfo>(); 529 XmlPullParser parser = Xml.newPullParser(); 530 parser.setInput(in, null); 531 parseState(parser, printers); 532 // Take a note which version of the history was read. 533 mLastReadHistoryTimestamp = mStatePersistFile.getBaseFile().lastModified(); 534 return printers; 535 } catch (IllegalStateException ise) { 536 Slog.w(LOG_TAG, "Failed parsing ", ise); 537 } catch (NullPointerException npe) { 538 Slog.w(LOG_TAG, "Failed parsing ", npe); 539 } catch (NumberFormatException nfe) { 540 Slog.w(LOG_TAG, "Failed parsing ", nfe); 541 } catch (XmlPullParserException xppe) { 542 Slog.w(LOG_TAG, "Failed parsing ", xppe); 543 } catch (IOException ioe) { 544 Slog.w(LOG_TAG, "Failed parsing ", ioe); 545 } catch (IndexOutOfBoundsException iobe) { 546 Slog.w(LOG_TAG, "Failed parsing ", iobe); 547 } finally { 548 IoUtils.closeQuietly(in); 549 } 550 551 return Collections.emptyList(); 552 } 553 554 private void parseState(XmlPullParser parser, List<PrinterInfo> outPrinters) 555 throws IOException, XmlPullParserException { 556 parser.next(); 557 skipEmptyTextTags(parser); 558 expect(parser, XmlPullParser.START_TAG, TAG_PRINTERS); 559 parser.next(); 560 561 while (parsePrinter(parser, outPrinters)) { 562 // Be nice and respond to cancellation 563 if (isCancelled()) { 564 return; 565 } 566 parser.next(); 567 } 568 569 skipEmptyTextTags(parser); 570 expect(parser, XmlPullParser.END_TAG, TAG_PRINTERS); 571 } 572 573 private boolean parsePrinter(XmlPullParser parser, List<PrinterInfo> outPrinters) 574 throws IOException, XmlPullParserException { 575 skipEmptyTextTags(parser); 576 if (!accept(parser, XmlPullParser.START_TAG, TAG_PRINTER)) { 577 return false; 578 } 579 580 String name = parser.getAttributeValue(null, ATTR_NAME); 581 String description = parser.getAttributeValue(null, ATTR_DESCRIPTION); 582 final int status = Integer.parseInt(parser.getAttributeValue(null, ATTR_STATUS)); 583 584 parser.next(); 585 586 skipEmptyTextTags(parser); 587 expect(parser, XmlPullParser.START_TAG, TAG_PRINTER_ID); 588 String localId = parser.getAttributeValue(null, ATTR_LOCAL_ID); 589 ComponentName service = ComponentName.unflattenFromString(parser.getAttributeValue( 590 null, ATTR_SERVICE_NAME)); 591 PrinterId printerId = new PrinterId(service, localId); 592 parser.next(); 593 skipEmptyTextTags(parser); 594 expect(parser, XmlPullParser.END_TAG, TAG_PRINTER_ID); 595 parser.next(); 596 597 PrinterInfo.Builder builder = new PrinterInfo.Builder(printerId, name, status); 598 builder.setDescription(description); 599 PrinterInfo printer = builder.build(); 600 601 outPrinters.add(printer); 602 603 if (DEBUG) { 604 Log.i(LOG_TAG, "[RESTORED] " + printer); 605 } 606 607 skipEmptyTextTags(parser); 608 expect(parser, XmlPullParser.END_TAG, TAG_PRINTER); 609 610 return true; 611 } 612 613 private void expect(XmlPullParser parser, int type, String tag) 614 throws IOException, XmlPullParserException { 615 if (!accept(parser, type, tag)) { 616 throw new XmlPullParserException("Exepected event: " + type 617 + " and tag: " + tag + " but got event: " + parser.getEventType() 618 + " and tag:" + parser.getName()); 619 } 620 } 621 622 private void skipEmptyTextTags(XmlPullParser parser) 623 throws IOException, XmlPullParserException { 624 while (accept(parser, XmlPullParser.TEXT, null) 625 && "\n".equals(parser.getText())) { 626 parser.next(); 627 } 628 } 629 630 private boolean accept(XmlPullParser parser, int type, String tag) 631 throws IOException, XmlPullParserException { 632 if (parser.getEventType() != type) { 633 return false; 634 } 635 if (tag != null) { 636 if (!tag.equals(parser.getName())) { 637 return false; 638 } 639 } else if (parser.getName() != null) { 640 return false; 641 } 642 return true; 643 } 644 }; 645 646 private final class WriteTask extends AsyncTask<List<PrinterInfo>, Void, Void> { 647 @Override 648 protected Void doInBackground(List<PrinterInfo>... printers) { 649 doWritePrinterHistory(printers[0]); 650 return null; 651 } 652 653 private void doWritePrinterHistory(List<PrinterInfo> printers) { 654 FileOutputStream out = null; 655 try { 656 out = mStatePersistFile.startWrite(); 657 658 XmlSerializer serializer = new FastXmlSerializer(); 659 serializer.setOutput(out, "utf-8"); 660 serializer.startDocument(null, true); 661 serializer.startTag(null, TAG_PRINTERS); 662 663 final int printerCount = printers.size(); 664 for (int i = 0; i < printerCount; i++) { 665 PrinterInfo printer = printers.get(i); 666 667 serializer.startTag(null, TAG_PRINTER); 668 669 serializer.attribute(null, ATTR_NAME, printer.getName()); 670 // Historical printers are always stored as unavailable. 671 serializer.attribute(null, ATTR_STATUS, String.valueOf( 672 PrinterInfo.STATUS_UNAVAILABLE)); 673 String description = printer.getDescription(); 674 if (description != null) { 675 serializer.attribute(null, ATTR_DESCRIPTION, description); 676 } 677 678 PrinterId printerId = printer.getId(); 679 serializer.startTag(null, TAG_PRINTER_ID); 680 serializer.attribute(null, ATTR_LOCAL_ID, printerId.getLocalId()); 681 serializer.attribute(null, ATTR_SERVICE_NAME, printerId.getServiceName() 682 .flattenToString()); 683 serializer.endTag(null, TAG_PRINTER_ID); 684 685 serializer.endTag(null, TAG_PRINTER); 686 687 if (DEBUG) { 688 Log.i(LOG_TAG, "[PERSISTED] " + printer); 689 } 690 } 691 692 serializer.endTag(null, TAG_PRINTERS); 693 serializer.endDocument(); 694 mStatePersistFile.finishWrite(out); 695 696 if (DEBUG) { 697 Log.i(LOG_TAG, "[PERSIST END]"); 698 } 699 } catch (IOException ioe) { 700 Slog.w(LOG_TAG, "Failed to write printer history, restoring backup.", ioe); 701 mStatePersistFile.failWrite(out); 702 } finally { 703 IoUtils.closeQuietly(out); 704 } 705 } 706 }; 707 } 708 } 709
