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 
17 package com.android.server.am;
18 
19 import static android.content.Intent.FLAG_ACTIVITY_MULTIPLE_TASK;
20 import static android.content.Intent.FLAG_ACTIVITY_NEW_DOCUMENT;
21 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
22 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_RECENTS;
23 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_TASKS;
24 import static com.android.server.am.ActivityManagerDebugConfig.POSTFIX_RECENTS;
25 import static com.android.server.am.ActivityManagerDebugConfig.POSTFIX_TASKS;
26 import static com.android.server.am.ActivityManagerDebugConfig.TAG_AM;
27 import static com.android.server.am.ActivityManagerDebugConfig.TAG_WITH_CLASS_NAME;
28 import static com.android.server.am.TaskRecord.INVALID_TASK_ID;
29 
30 import com.google.android.collect.Sets;
31 
32 import android.app.ActivityManager;
33 import android.app.AppGlobals;
34 import android.content.ComponentName;
35 import android.content.Intent;
36 import android.content.pm.ActivityInfo;
37 import android.content.pm.ApplicationInfo;
38 import android.content.pm.IPackageManager;
39 import android.content.pm.PackageManager;
40 import android.graphics.Bitmap;
41 import android.os.Environment;
42 import android.os.RemoteException;
43 import android.os.UserHandle;
44 import android.util.ArraySet;
45 import android.util.Slog;
46 import android.util.SparseArray;
47 import android.util.SparseBooleanArray;
48 
49 import java.io.File;
50 import java.util.ArrayList;
51 import java.util.Arrays;
52 import java.util.Collections;
53 import java.util.Comparator;
54 import java.util.HashMap;
55 import java.util.Set;
56 
57 /**
58  * Class for managing the recent tasks list.
59  */
60 class RecentTasks extends ArrayList<TaskRecord> {
61     private static final String TAG = TAG_WITH_CLASS_NAME ? "RecentTasks" : TAG_AM;
62     private static final String TAG_RECENTS = TAG + POSTFIX_RECENTS;
63     private static final String TAG_TASKS = TAG + POSTFIX_TASKS;
64 
65     // Maximum number recent bitmaps to keep in memory.
66     private static final int MAX_RECENT_BITMAPS = 3;
67     private static final int DEFAULT_INITIAL_CAPACITY = 5;
68 
69     // Whether or not to move all affiliated tasks to the front when one of the tasks is launched
70     private static final boolean MOVE_AFFILIATED_TASKS_TO_FRONT = false;
71 
72     /**
73      * Save recent tasks information across reboots.
74      */
75     private final TaskPersister mTaskPersister;
76     private final ActivityManagerService mService;
77     private final SparseBooleanArray mUsersWithRecentsLoaded = new SparseBooleanArray(
78             DEFAULT_INITIAL_CAPACITY);
79 
80     /**
81      * Stores for each user task ids that are taken by tasks residing in persistent storage. These
82      * tasks may or may not currently be in memory.
83      */
84     final SparseArray<SparseBooleanArray> mPersistedTaskIds = new SparseArray<>(
85             DEFAULT_INITIAL_CAPACITY);
86 
87     // Mainly to avoid object recreation on multiple calls.
88     private final ArrayList<TaskRecord> mTmpRecents = new ArrayList<TaskRecord>();
89     private final HashMap<ComponentName, ActivityInfo> mTmpAvailActCache = new HashMap<>();
90     private final HashMap<String, ApplicationInfo> mTmpAvailAppCache = new HashMap<>();
91     private final ActivityInfo mTmpActivityInfo = new ActivityInfo();
92     private final ApplicationInfo mTmpAppInfo = new ApplicationInfo();
93 
RecentTasks(ActivityManagerService service, ActivityStackSupervisor mStackSupervisor)94     RecentTasks(ActivityManagerService service, ActivityStackSupervisor mStackSupervisor) {
95         File systemDir = Environment.getDataSystemDirectory();
96         mService = service;
97         mTaskPersister = new TaskPersister(systemDir, mStackSupervisor, service, this);
98         mStackSupervisor.setRecentTasks(this);
99     }
100 
101     /**
102      * Loads the persistent recentTasks for {@code userId} into this list from persistent storage.
103      * Does nothing if they are already loaded.
104      *
105      * @param userId the user Id
106      */
loadUserRecentsLocked(int userId)107     void loadUserRecentsLocked(int userId) {
108         if (mUsersWithRecentsLoaded.get(userId)) {
109             return;
110         }
111 
112         // Load the task ids if not loaded.
113         loadPersistedTaskIdsForUserLocked(userId);
114 
115         // Check if any tasks are added before recents is loaded
116         final SparseBooleanArray preaddedTasks = new SparseBooleanArray();
117         for (final TaskRecord task : this) {
118             if (task.userId == userId && shouldPersistTaskLocked(task)) {
119                 preaddedTasks.put(task.taskId, true);
120             }
121         }
122 
123         Slog.i(TAG, "Loading recents for user " + userId + " into memory.");
124         addAll(mTaskPersister.restoreTasksForUserLocked(userId, preaddedTasks));
125         cleanupLocked(userId);
126         mUsersWithRecentsLoaded.put(userId, true);
127 
128         // If we have tasks added before loading recents, we need to update persistent task IDs.
129         if (preaddedTasks.size() > 0) {
130             syncPersistentTaskIdsLocked();
131         }
132     }
133 
loadPersistedTaskIdsForUserLocked(int userId)134     private void loadPersistedTaskIdsForUserLocked(int userId) {
135         // An empty instead of a null set here means that no persistent taskIds were present
136         // on file when we loaded them.
137         if (mPersistedTaskIds.get(userId) == null) {
138             mPersistedTaskIds.put(userId, mTaskPersister.loadPersistedTaskIdsForUser(userId));
139             Slog.i(TAG, "Loaded persisted task ids for user " + userId);
140         }
141     }
142 
taskIdTakenForUserLocked(int taskId, int userId)143     boolean taskIdTakenForUserLocked(int taskId, int userId) {
144         loadPersistedTaskIdsForUserLocked(userId);
145         return mPersistedTaskIds.get(userId).get(taskId);
146     }
147 
notifyTaskPersisterLocked(TaskRecord task, boolean flush)148     void notifyTaskPersisterLocked(TaskRecord task, boolean flush) {
149         final ActivityStack stack = task != null ? task.getStack() : null;
150         if (stack != null && stack.isHomeOrRecentsStack()) {
151             // Never persist the home or recents stack.
152             return;
153         }
154         syncPersistentTaskIdsLocked();
155         mTaskPersister.wakeup(task, flush);
156     }
157 
syncPersistentTaskIdsLocked()158     private void syncPersistentTaskIdsLocked() {
159         for (int i = mPersistedTaskIds.size() - 1; i >= 0; i--) {
160             int userId = mPersistedTaskIds.keyAt(i);
161             if (mUsersWithRecentsLoaded.get(userId)) {
162                 // Recents are loaded only after task ids are loaded. Therefore, the set of taskids
163                 // referenced here should not be null.
164                 mPersistedTaskIds.valueAt(i).clear();
165             }
166         }
167         for (int i = size() - 1; i >= 0; i--) {
168             final TaskRecord task = get(i);
169             if (shouldPersistTaskLocked(task)) {
170                 // Set of persisted taskIds for task.userId should not be null here
171                 // TODO Investigate why it can happen. For now initialize with an empty set
172                 if (mPersistedTaskIds.get(task.userId) == null) {
173                     Slog.wtf(TAG, "No task ids found for userId " + task.userId + ". task=" + task
174                             + " mPersistedTaskIds=" + mPersistedTaskIds);
175                     mPersistedTaskIds.put(task.userId, new SparseBooleanArray());
176                 }
177                 mPersistedTaskIds.get(task.userId).put(task.taskId, true);
178             }
179         }
180     }
181 
shouldPersistTaskLocked(TaskRecord task)182     private static boolean shouldPersistTaskLocked(TaskRecord task) {
183         final ActivityStack<?> stack = task.getStack();
184         return task.isPersistable && (stack == null || !stack.isHomeOrRecentsStack());
185     }
186 
onSystemReadyLocked()187     void onSystemReadyLocked() {
188         clear();
189         mTaskPersister.startPersisting();
190     }
191 
getTaskDescriptionIcon(String path)192     Bitmap getTaskDescriptionIcon(String path) {
193         return mTaskPersister.getTaskDescriptionIcon(path);
194     }
195 
getImageFromWriteQueue(String path)196     Bitmap getImageFromWriteQueue(String path) {
197         return mTaskPersister.getImageFromWriteQueue(path);
198     }
199 
saveImage(Bitmap image, String path)200     void saveImage(Bitmap image, String path) {
201         mTaskPersister.saveImage(image, path);
202     }
203 
flush()204     void flush() {
205         synchronized (mService) {
206             syncPersistentTaskIdsLocked();
207         }
208         mTaskPersister.flush();
209     }
210 
211     /**
212      * Returns all userIds for which recents from persistent storage are loaded into this list.
213      *
214      * @return an array of userIds.
215      */
usersWithRecentsLoadedLocked()216     int[] usersWithRecentsLoadedLocked() {
217         int[] usersWithRecentsLoaded = new int[mUsersWithRecentsLoaded.size()];
218         int len = 0;
219         for (int i = 0; i < usersWithRecentsLoaded.length; i++) {
220             int userId = mUsersWithRecentsLoaded.keyAt(i);
221             if (mUsersWithRecentsLoaded.valueAt(i)) {
222                 usersWithRecentsLoaded[len++] = userId;
223             }
224         }
225         if (len < usersWithRecentsLoaded.length) {
226             // should never happen.
227             return Arrays.copyOf(usersWithRecentsLoaded, len);
228         }
229         return usersWithRecentsLoaded;
230     }
231 
unloadUserRecentsLocked(int userId)232     private void unloadUserRecentsLocked(int userId) {
233         if (mUsersWithRecentsLoaded.get(userId)) {
234             Slog.i(TAG, "Unloading recents for user " + userId + " from memory.");
235             mUsersWithRecentsLoaded.delete(userId);
236             removeTasksForUserLocked(userId);
237         }
238     }
239 
240     /**
241      * Removes recent tasks and any other state kept in memory for the passed in user. Does not
242      * touch the information present on persistent storage.
243      *
244      * @param userId the id of the user
245      */
unloadUserDataFromMemoryLocked(int userId)246     void unloadUserDataFromMemoryLocked(int userId) {
247         unloadUserRecentsLocked(userId);
248         mPersistedTaskIds.delete(userId);
249         mTaskPersister.unloadUserDataFromMemory(userId);
250     }
251 
taskForIdLocked(int id)252     TaskRecord taskForIdLocked(int id) {
253         final int recentsCount = size();
254         for (int i = 0; i < recentsCount; i++) {
255             TaskRecord tr = get(i);
256             if (tr.taskId == id) {
257                 return tr;
258             }
259         }
260         return null;
261     }
262 
263     /** Remove recent tasks for a user. */
removeTasksForUserLocked(int userId)264     void removeTasksForUserLocked(int userId) {
265         if(userId <= 0) {
266             Slog.i(TAG, "Can't remove recent task on user " + userId);
267             return;
268         }
269 
270         for (int i = size() - 1; i >= 0; --i) {
271             TaskRecord tr = get(i);
272             if (tr.userId == userId) {
273                 if(DEBUG_TASKS) Slog.i(TAG_TASKS,
274                         "remove RecentTask " + tr + " when finishing user" + userId);
275                 remove(i);
276                 tr.removedFromRecents();
277             }
278         }
279     }
280 
onPackagesSuspendedChanged(String[] packages, boolean suspended, int userId)281     void onPackagesSuspendedChanged(String[] packages, boolean suspended, int userId) {
282         final Set<String> packageNames = Sets.newHashSet(packages);
283         for (int i = size() - 1; i >= 0; --i) {
284             final TaskRecord tr = get(i);
285             if (tr.realActivity != null
286                     && packageNames.contains(tr.realActivity.getPackageName())
287                     && tr.userId == userId
288                     && tr.realActivitySuspended != suspended) {
289                tr.realActivitySuspended = suspended;
290                notifyTaskPersisterLocked(tr, false);
291             }
292         }
293 
294     }
295 
296     /**
297      * Update the recent tasks lists: make sure tasks should still be here (their
298      * applications / activities still exist), update their availability, fix-up ordering
299      * of affiliations.
300      */
cleanupLocked(int userId)301     void cleanupLocked(int userId) {
302         int recentsCount = size();
303         if (recentsCount == 0) {
304             // Happens when called from the packagemanager broadcast before boot,
305             // or just any empty list.
306             return;
307         }
308 
309         final IPackageManager pm = AppGlobals.getPackageManager();
310         for (int i = recentsCount - 1; i >= 0; i--) {
311             final TaskRecord task = get(i);
312             if (userId != UserHandle.USER_ALL && task.userId != userId) {
313                 // Only look at tasks for the user ID of interest.
314                 continue;
315             }
316             if (task.autoRemoveRecents && task.getTopActivity() == null) {
317                 // This situation is broken, and we should just get rid of it now.
318                 remove(i);
319                 task.removedFromRecents();
320                 Slog.w(TAG, "Removing auto-remove without activity: " + task);
321                 continue;
322             }
323             // Check whether this activity is currently available.
324             if (task.realActivity != null) {
325                 ActivityInfo ai = mTmpAvailActCache.get(task.realActivity);
326                 if (ai == null) {
327                     try {
328                         // At this first cut, we're only interested in
329                         // activities that are fully runnable based on
330                         // current system state.
331                         ai = pm.getActivityInfo(task.realActivity,
332                                 PackageManager.MATCH_DEBUG_TRIAGED_MISSING, userId);
333                     } catch (RemoteException e) {
334                         // Will never happen.
335                         continue;
336                     }
337                     if (ai == null) {
338                         ai = mTmpActivityInfo;
339                     }
340                     mTmpAvailActCache.put(task.realActivity, ai);
341                 }
342                 if (ai == mTmpActivityInfo) {
343                     // This could be either because the activity no longer exists, or the
344                     // app is temporarily gone. For the former we want to remove the recents
345                     // entry; for the latter we want to mark it as unavailable.
346                     ApplicationInfo app = mTmpAvailAppCache
347                             .get(task.realActivity.getPackageName());
348                     if (app == null) {
349                         try {
350                             app = pm.getApplicationInfo(task.realActivity.getPackageName(),
351                                     PackageManager.MATCH_UNINSTALLED_PACKAGES, userId);
352                         } catch (RemoteException e) {
353                             // Will never happen.
354                             continue;
355                         }
356                         if (app == null) {
357                             app = mTmpAppInfo;
358                         }
359                         mTmpAvailAppCache.put(task.realActivity.getPackageName(), app);
360                     }
361                     if (app == mTmpAppInfo
362                             || (app.flags & ApplicationInfo.FLAG_INSTALLED) == 0) {
363                         // Doesn't exist any more! Good-bye.
364                         remove(i);
365                         task.removedFromRecents();
366                         Slog.w(TAG, "Removing no longer valid recent: " + task);
367                         continue;
368                     } else {
369                         // Otherwise just not available for now.
370                         if (DEBUG_RECENTS && task.isAvailable) Slog.d(TAG_RECENTS,
371                                 "Making recent unavailable: " + task);
372                         task.isAvailable = false;
373                     }
374                 } else {
375                     if (!ai.enabled || !ai.applicationInfo.enabled
376                             || (ai.applicationInfo.flags
377                                     & ApplicationInfo.FLAG_INSTALLED) == 0) {
378                         if (DEBUG_RECENTS && task.isAvailable) Slog.d(TAG_RECENTS,
379                                 "Making recent unavailable: " + task
380                                         + " (enabled=" + ai.enabled + "/"
381                                         + ai.applicationInfo.enabled
382                                         + " flags="
383                                         + Integer.toHexString(ai.applicationInfo.flags)
384                                         + ")");
385                         task.isAvailable = false;
386                     } else {
387                         if (DEBUG_RECENTS && !task.isAvailable) Slog.d(TAG_RECENTS,
388                                 "Making recent available: " + task);
389                         task.isAvailable = true;
390                     }
391                 }
392             }
393         }
394 
395         // Verify the affiliate chain for each task.
396         int i = 0;
397         recentsCount = size();
398         while (i < recentsCount) {
399             i = processNextAffiliateChainLocked(i);
400         }
401         // recent tasks are now in sorted, affiliated order.
402     }
403 
moveAffiliatedTasksToFront(TaskRecord task, int taskIndex)404     private final boolean moveAffiliatedTasksToFront(TaskRecord task, int taskIndex) {
405         int recentsCount = size();
406         TaskRecord top = task;
407         int topIndex = taskIndex;
408         while (top.mNextAffiliate != null && topIndex > 0) {
409             top = top.mNextAffiliate;
410             topIndex--;
411         }
412         if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: adding affilliates starting at "
413                 + topIndex + " from intial " + taskIndex);
414         // Find the end of the chain, doing a sanity check along the way.
415         boolean sane = top.mAffiliatedTaskId == task.mAffiliatedTaskId;
416         int endIndex = topIndex;
417         TaskRecord prev = top;
418         while (endIndex < recentsCount) {
419             TaskRecord cur = get(endIndex);
420             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: looking at next chain @"
421                     + endIndex + " " + cur);
422             if (cur == top) {
423                 // Verify start of the chain.
424                 if (cur.mNextAffiliate != null || cur.mNextAffiliateTaskId != INVALID_TASK_ID) {
425                     Slog.wtf(TAG, "Bad chain @" + endIndex
426                             + ": first task has next affiliate: " + prev);
427                     sane = false;
428                     break;
429                 }
430             } else {
431                 // Verify middle of the chain's next points back to the one before.
432                 if (cur.mNextAffiliate != prev
433                         || cur.mNextAffiliateTaskId != prev.taskId) {
434                     Slog.wtf(TAG, "Bad chain @" + endIndex
435                             + ": middle task " + cur + " @" + endIndex
436                             + " has bad next affiliate "
437                             + cur.mNextAffiliate + " id " + cur.mNextAffiliateTaskId
438                             + ", expected " + prev);
439                     sane = false;
440                     break;
441                 }
442             }
443             if (cur.mPrevAffiliateTaskId == INVALID_TASK_ID) {
444                 // Chain ends here.
445                 if (cur.mPrevAffiliate != null) {
446                     Slog.wtf(TAG, "Bad chain @" + endIndex
447                             + ": last task " + cur + " has previous affiliate "
448                             + cur.mPrevAffiliate);
449                     sane = false;
450                 }
451                 if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: end of chain @" + endIndex);
452                 break;
453             } else {
454                 // Verify middle of the chain's prev points to a valid item.
455                 if (cur.mPrevAffiliate == null) {
456                     Slog.wtf(TAG, "Bad chain @" + endIndex
457                             + ": task " + cur + " has previous affiliate "
458                             + cur.mPrevAffiliate + " but should be id "
459                             + cur.mPrevAffiliate);
460                     sane = false;
461                     break;
462                 }
463             }
464             if (cur.mAffiliatedTaskId != task.mAffiliatedTaskId) {
465                 Slog.wtf(TAG, "Bad chain @" + endIndex
466                         + ": task " + cur + " has affiliated id "
467                         + cur.mAffiliatedTaskId + " but should be "
468                         + task.mAffiliatedTaskId);
469                 sane = false;
470                 break;
471             }
472             prev = cur;
473             endIndex++;
474             if (endIndex >= recentsCount) {
475                 Slog.wtf(TAG, "Bad chain ran off index " + endIndex
476                         + ": last task " + prev);
477                 sane = false;
478                 break;
479             }
480         }
481         if (sane) {
482             if (endIndex < taskIndex) {
483                 Slog.wtf(TAG, "Bad chain @" + endIndex
484                         + ": did not extend to task " + task + " @" + taskIndex);
485                 sane = false;
486             }
487         }
488         if (sane) {
489             // All looks good, we can just move all of the affiliated tasks
490             // to the top.
491             for (int i=topIndex; i<=endIndex; i++) {
492                 if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: moving affiliated " + task
493                         + " from " + i + " to " + (i-topIndex));
494                 TaskRecord cur = remove(i);
495                 add(i - topIndex, cur);
496             }
497             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: done moving tasks  " +  topIndex
498                     + " to " + endIndex);
499             return true;
500         }
501 
502         // Whoops, couldn't do it.
503         return false;
504     }
505 
addLocked(TaskRecord task)506     final void addLocked(TaskRecord task) {
507         final boolean isAffiliated = task.mAffiliatedTaskId != task.taskId
508                 || task.mNextAffiliateTaskId != INVALID_TASK_ID
509                 || task.mPrevAffiliateTaskId != INVALID_TASK_ID;
510 
511         int recentsCount = size();
512         // Quick case: never add voice sessions.
513         // TODO: VI what about if it's just an activity?
514         // Probably nothing to do here
515         if (task.voiceSession != null) {
516             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS,
517                     "addRecent: not adding voice interaction " + task);
518             return;
519         }
520         // Another quick case: check if the top-most recent task is the same.
521         if (!isAffiliated && recentsCount > 0 && get(0) == task) {
522             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: already at top: " + task);
523             return;
524         }
525         // Another quick case: check if this is part of a set of affiliated
526         // tasks that are at the top.
527         if (isAffiliated && recentsCount > 0 && task.inRecents
528                 && task.mAffiliatedTaskId == get(0).mAffiliatedTaskId) {
529             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: affiliated " + get(0)
530                     + " at top when adding " + task);
531             return;
532         }
533 
534         boolean needAffiliationFix = false;
535 
536         // Slightly less quick case: the task is already in recents, so all we need
537         // to do is move it.
538         if (task.inRecents) {
539             int taskIndex = indexOf(task);
540             if (taskIndex >= 0) {
541                 if (!isAffiliated || MOVE_AFFILIATED_TASKS_TO_FRONT) {
542                     // Simple case: this is not an affiliated task, so we just move it to the front.
543                     remove(taskIndex);
544                     add(0, task);
545                     notifyTaskPersisterLocked(task, false);
546                     if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: moving to top " + task
547                             + " from " + taskIndex);
548                     return;
549                 } else {
550                     // More complicated: need to keep all affiliated tasks together.
551                     if (moveAffiliatedTasksToFront(task, taskIndex)) {
552                         // All went well.
553                         return;
554                     }
555 
556                     // Uh oh...  something bad in the affiliation chain, try to rebuild
557                     // everything and then go through our general path of adding a new task.
558                     needAffiliationFix = true;
559                 }
560             } else {
561                 Slog.wtf(TAG, "Task with inRecent not in recents: " + task);
562                 needAffiliationFix = true;
563             }
564         }
565 
566         if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: trimming tasks for " + task);
567         trimForTaskLocked(task, true);
568 
569         recentsCount = size();
570         final int maxRecents = ActivityManager.getMaxRecentTasksStatic();
571         while (recentsCount >= maxRecents) {
572             final TaskRecord tr = remove(recentsCount - 1);
573             tr.removedFromRecents();
574             recentsCount--;
575         }
576         task.inRecents = true;
577         if (!isAffiliated || needAffiliationFix) {
578             // If this is a simple non-affiliated task, or we had some failure trying to
579             // handle it as part of an affilated task, then just place it at the top.
580             add(0, task);
581             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: adding " + task);
582         } else if (isAffiliated) {
583             // If this is a new affiliated task, then move all of the affiliated tasks
584             // to the front and insert this new one.
585             TaskRecord other = task.mNextAffiliate;
586             if (other == null) {
587                 other = task.mPrevAffiliate;
588             }
589             if (other != null) {
590                 int otherIndex = indexOf(other);
591                 if (otherIndex >= 0) {
592                     // Insert new task at appropriate location.
593                     int taskIndex;
594                     if (other == task.mNextAffiliate) {
595                         // We found the index of our next affiliation, which is who is
596                         // before us in the list, so add after that point.
597                         taskIndex = otherIndex+1;
598                     } else {
599                         // We found the index of our previous affiliation, which is who is
600                         // after us in the list, so add at their position.
601                         taskIndex = otherIndex;
602                     }
603                     if (DEBUG_RECENTS) Slog.d(TAG_RECENTS,
604                             "addRecent: new affiliated task added at " + taskIndex + ": " + task);
605                     add(taskIndex, task);
606 
607                     // Now move everything to the front.
608                     if (moveAffiliatedTasksToFront(task, taskIndex)) {
609                         // All went well.
610                         return;
611                     }
612 
613                     // Uh oh...  something bad in the affiliation chain, try to rebuild
614                     // everything and then go through our general path of adding a new task.
615                     needAffiliationFix = true;
616                 } else {
617                     if (DEBUG_RECENTS) Slog.d(TAG_RECENTS,
618                             "addRecent: couldn't find other affiliation " + other);
619                     needAffiliationFix = true;
620                 }
621             } else {
622                 if (DEBUG_RECENTS) Slog.d(TAG_RECENTS,
623                         "addRecent: adding affiliated task without next/prev:" + task);
624                 needAffiliationFix = true;
625             }
626         }
627 
628         if (needAffiliationFix) {
629             if (DEBUG_RECENTS) Slog.d(TAG_RECENTS, "addRecent: regrouping affiliations");
630             cleanupLocked(task.userId);
631         }
632     }
633 
634     /**
635      * If needed, remove oldest existing entries in recents that are for the same kind
636      * of task as the given one.
637      */
trimForTaskLocked(TaskRecord task, boolean doTrim)638     int trimForTaskLocked(TaskRecord task, boolean doTrim) {
639         int recentsCount = size();
640         final Intent intent = task.intent;
641         final boolean document = intent != null && intent.isDocument();
642         int maxRecents = task.maxRecents - 1;
643         final ActivityStack stack = task.getStack();
644         for (int i = 0; i < recentsCount; i++) {
645             final TaskRecord tr = get(i);
646             final ActivityStack trStack = tr.getStack();
647             if (task != tr) {
648                 if (stack != null && trStack != null && stack != trStack) {
649                     continue;
650                 }
651                 if (task.userId != tr.userId) {
652                     continue;
653                 }
654                 if (i > MAX_RECENT_BITMAPS) {
655                     tr.freeLastThumbnail();
656                 }
657                 final Intent trIntent = tr.intent;
658                 final boolean sameAffinity =
659                         task.affinity != null && task.affinity.equals(tr.affinity);
660                 final boolean sameIntentFilter = intent != null && intent.filterEquals(trIntent);
661                 boolean multiTasksAllowed = false;
662                 final int flags = intent.getFlags();
663                 if ((flags & (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_NEW_DOCUMENT)) != 0
664                         && (flags & FLAG_ACTIVITY_MULTIPLE_TASK) != 0) {
665                     multiTasksAllowed = true;
666                 }
667                 final boolean trIsDocument = trIntent != null && trIntent.isDocument();
668                 final boolean bothDocuments = document && trIsDocument;
669                 if (!sameAffinity && !sameIntentFilter && !bothDocuments) {
670                     continue;
671                 }
672 
673                 if (bothDocuments) {
674                     // Do these documents belong to the same activity?
675                     final boolean sameActivity = task.realActivity != null
676                             && tr.realActivity != null
677                             && task.realActivity.equals(tr.realActivity);
678                     // If the document is open in another app or is not the same
679                     // document, we don't need to trim it.
680                     if (!sameActivity) {
681                         continue;
682                     // Otherwise only trim if we are over our max recents for this task
683                     } else if (maxRecents > 0) {
684                         --maxRecents;
685                         if (!doTrim || !sameIntentFilter || multiTasksAllowed) {
686                             // We don't want to trim if we are not over the max allowed entries and
687                             // the caller doesn't want us to trim, the tasks are not of the same
688                             // intent filter, or multiple entries fot the task is allowed.
689                             continue;
690                         }
691                     }
692                     // Hit the maximum number of documents for this task. Fall through
693                     // and remove this document from recents.
694                 } else if (document || trIsDocument) {
695                     // Only one of these is a document. Not the droid we're looking for.
696                     continue;
697                 }
698             }
699 
700             if (!doTrim) {
701                 // If the caller is not actually asking for a trim, just tell them we reached
702                 // a point where the trim would happen.
703                 return i;
704             }
705 
706             // Either task and tr are the same or, their affinities match or their intents match
707             // and neither of them is a document, or they are documents using the same activity
708             // and their maxRecents has been reached.
709             tr.disposeThumbnail();
710             remove(i);
711             if (task != tr) {
712                 tr.removedFromRecents();
713             }
714             i--;
715             recentsCount--;
716             if (task.intent == null) {
717                 // If the new recent task we are adding is not fully
718                 // specified, then replace it with the existing recent task.
719                 task = tr;
720             }
721             notifyTaskPersisterLocked(tr, false);
722         }
723 
724         return -1;
725     }
726 
727     // Sort by taskId
728     private static Comparator<TaskRecord> sTaskRecordComparator = new Comparator<TaskRecord>() {
729         @Override
730         public int compare(TaskRecord lhs, TaskRecord rhs) {
731             return rhs.taskId - lhs.taskId;
732         }
733     };
734 
735     // Extract the affiliates of the chain containing recent at index start.
processNextAffiliateChainLocked(int start)736     private int processNextAffiliateChainLocked(int start) {
737         final TaskRecord startTask = get(start);
738         final int affiliateId = startTask.mAffiliatedTaskId;
739 
740         // Quick identification of isolated tasks. I.e. those not launched behind.
741         if (startTask.taskId == affiliateId && startTask.mPrevAffiliate == null &&
742                 startTask.mNextAffiliate == null) {
743             // There is still a slim chance that there are other tasks that point to this task
744             // and that the chain is so messed up that this task no longer points to them but
745             // the gain of this optimization outweighs the risk.
746             startTask.inRecents = true;
747             return start + 1;
748         }
749 
750         // Remove all tasks that are affiliated to affiliateId and put them in mTmpRecents.
751         mTmpRecents.clear();
752         for (int i = size() - 1; i >= start; --i) {
753             final TaskRecord task = get(i);
754             if (task.mAffiliatedTaskId == affiliateId) {
755                 remove(i);
756                 mTmpRecents.add(task);
757             }
758         }
759 
760         // Sort them all by taskId. That is the order they were create in and that order will
761         // always be correct.
762         Collections.sort(mTmpRecents, sTaskRecordComparator);
763 
764         // Go through and fix up the linked list.
765         // The first one is the end of the chain and has no next.
766         final TaskRecord first = mTmpRecents.get(0);
767         first.inRecents = true;
768         if (first.mNextAffiliate != null) {
769             Slog.w(TAG, "Link error 1 first.next=" + first.mNextAffiliate);
770             first.setNextAffiliate(null);
771             notifyTaskPersisterLocked(first, false);
772         }
773         // Everything in the middle is doubly linked from next to prev.
774         final int tmpSize = mTmpRecents.size();
775         for (int i = 0; i < tmpSize - 1; ++i) {
776             final TaskRecord next = mTmpRecents.get(i);
777             final TaskRecord prev = mTmpRecents.get(i + 1);
778             if (next.mPrevAffiliate != prev) {
779                 Slog.w(TAG, "Link error 2 next=" + next + " prev=" + next.mPrevAffiliate +
780                         " setting prev=" + prev);
781                 next.setPrevAffiliate(prev);
782                 notifyTaskPersisterLocked(next, false);
783             }
784             if (prev.mNextAffiliate != next) {
785                 Slog.w(TAG, "Link error 3 prev=" + prev + " next=" + prev.mNextAffiliate +
786                         " setting next=" + next);
787                 prev.setNextAffiliate(next);
788                 notifyTaskPersisterLocked(prev, false);
789             }
790             prev.inRecents = true;
791         }
792         // The last one is the beginning of the list and has no prev.
793         final TaskRecord last = mTmpRecents.get(tmpSize - 1);
794         if (last.mPrevAffiliate != null) {
795             Slog.w(TAG, "Link error 4 last.prev=" + last.mPrevAffiliate);
796             last.setPrevAffiliate(null);
797             notifyTaskPersisterLocked(last, false);
798         }
799 
800         // Insert the group back into mRecentTasks at start.
801         addAll(start, mTmpRecents);
802         mTmpRecents.clear();
803 
804         // Let the caller know where we left off.
805         return start + tmpSize;
806     }
807 }
808