DO NOT MERGE ANYWHERE: UsageStats: Fix issue where initializing data for first time would cause crash

With the updated rolling window of stats for app idleness, we need to make sure
it is populated before we initialize some defaults.

Now that we look at older entries to figure out idleness, if those
entries are in the future (due to time change), set them to the current
screen on time.
Bug:26504153

Change-Id: Ia22add0e8eaf0f137002bbe3e91d747fef5b7d69
(cherry picked from commit 2bd90c6abce3e43af6db4eaa7a34459e8341b3a0)

2 files changed, 41 insertions, 35 deletions

diff --git a/services/usage/java/com/android/server/usage/UsageStatsService.java b/services/usage/java/com/android/server/usage/UsageStatsService.java
index 2b8afba57a32..4c1db8cf59a9 100644
--- a/services/usage/java/com/android/server/usage/UsageStatsService.java
+++ b/services/usage/java/com/android/server/usage/UsageStatsService.java
@@ -547,7 +547,8 @@ public class UsageStatsService extends SystemService implements
             final int userCount = mUserState.size();
             for (int i = 0; i < userCount; i++) {
                 final UserUsageStatsService service = mUserState.valueAt(i);
-                service.onTimeChanged(expectedSystemTime, actualSystemTime, resetBeginIdleTime);
+                service.onTimeChanged(expectedSystemTime, actualSystemTime, mScreenOnTime,
+                        resetBeginIdleTime);
             }
             mRealTimeSnapshot = actualRealtime;
             mSystemTimeSnapshot = actualSystemTime;
diff --git a/services/usage/java/com/android/server/usage/UserUsageStatsService.java b/services/usage/java/com/android/server/usage/UserUsageStatsService.java
index d8f26edaf85e..addb1a1737d4 100644
--- a/services/usage/java/com/android/server/usage/UserUsageStatsService.java
+++ b/services/usage/java/com/android/server/usage/UserUsageStatsService.java
@@ -135,12 +135,12 @@ class UserUsageStatsService {
             stat.updateConfigurationStats(null, stat.lastTimeSaved);
         }
 
+        refreshAppIdleRollingWindow(currentTimeMillis, deviceUsageTime);
+
         if (mDatabase.isNewUpdate()) {
             initializeDefaultsForApps(currentTimeMillis, deviceUsageTime,
                     mDatabase.isFirstUpdate());
         }
-
-        refreshAppIdleRollingWindow(currentTimeMillis);
     }
 
     /**
@@ -162,19 +162,23 @@ class UserUsageStatsService {
                 for (IntervalStats stats : mCurrentStats) {
                     stats.update(packageName, currentTimeMillis, Event.SYSTEM_INTERACTION);
                     stats.updateBeginIdleTime(packageName, deviceUsageTime);
-                    mStatsChanged = true;
                 }
+                mAppIdleRollingWindow.update(packageName, currentTimeMillis,
+                        Event.SYSTEM_INTERACTION);
+                mAppIdleRollingWindow.updateBeginIdleTime(packageName, deviceUsageTime);
+                mStatsChanged = true;
             }
         }
         // Persist the new OTA-related access stats.
         persistActiveStats();
     }
 
-    void onTimeChanged(long oldTime, long newTime, boolean resetBeginIdleTime) {
+    void onTimeChanged(long oldTime, long newTime, long deviceUsageTime,
+                       boolean resetBeginIdleTime) {
         persistActiveStats();
         mDatabase.onTimeChanged(newTime - oldTime);
         loadActiveStats(newTime, /* force= */ true, resetBeginIdleTime);
-        refreshAppIdleRollingWindow(newTime);
+        refreshAppIdleRollingWindow(newTime, deviceUsageTime);
     }
 
     void reportEvent(UsageEvents.Event event, long deviceUsageTime) {
@@ -186,7 +190,7 @@ class UserUsageStatsService {
 
         if (event.mTimeStamp >= mDailyExpiryDate.getTimeInMillis()) {
             // Need to rollover
-            rolloverStats(event.mTimeStamp);
+            rolloverStats(event.mTimeStamp, deviceUsageTime);
         }
 
         final IntervalStats currentDailyStats = mCurrentStats[UsageStatsManager.INTERVAL_DAILY];
@@ -430,7 +434,7 @@ class UserUsageStatsService {
         }
     }
 
-    private void rolloverStats(final long currentTimeMillis) {
+    private void rolloverStats(final long currentTimeMillis, final long deviceUsageTime) {
         final long startTime = SystemClock.elapsedRealtime();
         Slog.i(TAG, mLogPrefix + "Rolling over usage stats");
 
@@ -471,7 +475,7 @@ class UserUsageStatsService {
         }
         persistActiveStats();
 
-        refreshAppIdleRollingWindow(currentTimeMillis);
+        refreshAppIdleRollingWindow(currentTimeMillis, deviceUsageTime);
 
         final long totalTime = SystemClock.elapsedRealtime() - startTime;
         Slog.i(TAG, mLogPrefix + "Rolling over usage stats complete. Took " + totalTime
@@ -542,42 +546,28 @@ class UserUsageStatsService {
                 tempCal.getTimeInMillis() + ")");
     }
 
-    private static void mergePackageStats(IntervalStats dst, IntervalStats src) {
+    private static void mergePackageStats(IntervalStats dst, IntervalStats src,
+                                          final long deviceUsageTime) {
         dst.endTime = Math.max(dst.endTime, src.endTime);
 
         final int srcPackageCount = src.packageStats.size();
         for (int i = 0; i < srcPackageCount; i++) {
             final String packageName = src.packageStats.keyAt(i);
             final UsageStats srcStats = src.packageStats.valueAt(i);
-            final UsageStats dstStats = dst.packageStats.get(packageName);
+            UsageStats dstStats = dst.packageStats.get(packageName);
             if (dstStats == null) {
-                dst.packageStats.put(packageName, new UsageStats(srcStats));
+                dstStats = new UsageStats(srcStats);
+                dst.packageStats.put(packageName, dstStats);
             } else {
                 dstStats.add(src.packageStats.valueAt(i));
             }
-        }
-    }
 
-    /**
-     * Merges all the stats into the first element of the resulting list.
-     */
-    private static final StatCombiner<IntervalStats> sPackageStatsMerger =
-            new StatCombiner<IntervalStats>() {
-        @Override
-        public void combine(IntervalStats stats, boolean mutable,
-                            List<IntervalStats> accumulatedResult) {
-            IntervalStats accum;
-            if (accumulatedResult.isEmpty()) {
-                accum = new IntervalStats();
-                accum.beginTime = stats.beginTime;
-                accumulatedResult.add(accum);
-            } else {
-                accum = accumulatedResult.get(0);
+            // App idle times can not begin in the future. This happens if we had a time change.
+            if (dstStats.mBeginIdleTime > deviceUsageTime) {
+                dstStats.mBeginIdleTime = deviceUsageTime;
             }
-
-            mergePackageStats(accum, stats);
         }
-    };
+    }
 
     /**
      * App idle operates on a rolling window of time. When we roll over time, we end up with a
@@ -589,16 +579,31 @@ class UserUsageStatsService {
      *
      * @param currentTimeMillis
      */
-    void refreshAppIdleRollingWindow(long currentTimeMillis) {
+    void refreshAppIdleRollingWindow(final long currentTimeMillis, final long deviceUsageTime) {
         // Start the rolling window for AppIdle requests.
         List<IntervalStats> stats = mDatabase.queryUsageStats(UsageStatsManager.INTERVAL_DAILY,
                 currentTimeMillis - (1000 * 60 * 60 * 24 * 2), currentTimeMillis,
-                sPackageStatsMerger);
+                new StatCombiner<IntervalStats>() {
+                    @Override
+                    public void combine(IntervalStats stats, boolean mutable,
+                                        List<IntervalStats> accumulatedResult) {
+                        IntervalStats accum;
+                        if (accumulatedResult.isEmpty()) {
+                            accum = new IntervalStats();
+                            accum.beginTime = stats.beginTime;
+                            accumulatedResult.add(accum);
+                        } else {
+                            accum = accumulatedResult.get(0);
+                        }
+
+                        mergePackageStats(accum, stats, deviceUsageTime);
+                    }
+                });
 
         if (stats == null || stats.isEmpty()) {
             mAppIdleRollingWindow = new IntervalStats();
             mergePackageStats(mAppIdleRollingWindow,
-                    mCurrentStats[UsageStatsManager.INTERVAL_YEARLY]);
+                    mCurrentStats[UsageStatsManager.INTERVAL_YEARLY], deviceUsageTime);
         } else {
             mAppIdleRollingWindow = stats.get(0);
         }