Merge "Fix concurrency issue with BatteryUsageStats"

core/java/com/android/internal/os/BatteryUsageStatsProvider.java

@@ -21,11 +21,13 @@ import android.hardware.SensorManager;
 import android.os.BatteryStats;
 import android.os.BatteryUsageStats;
 import android.os.BatteryUsageStatsQuery;
+import android.os.Parcel;
 import android.os.SystemClock;
 import android.os.UidBatteryConsumer;
 import android.util.Log;
 import android.util.SparseArray;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 
 import java.util.ArrayList;
@@ -133,9 +135,12 @@ public class BatteryUsageStatsProvider {
      */
     @VisibleForTesting
     public BatteryUsageStats getBatteryUsageStats(BatteryUsageStatsQuery query) {
-        return getBatteryUsageStats(query, currentTimeMillis());
+        synchronized (mStats) {
+            return getBatteryUsageStats(query, currentTimeMillis());
+        }
     }
 
+    @GuardedBy("mStats")
     private BatteryUsageStats getBatteryUsageStats(BatteryUsageStatsQuery query,
             long currentTimeMs) {
         if (query.getToTimestamp() == 0) {
@@ -145,6 +150,7 @@ public class BatteryUsageStatsProvider {
         }
     }
 
+    @GuardedBy("mStats")
     private BatteryUsageStats getCurrentBatteryUsageStats(BatteryUsageStatsQuery query,
             long currentTimeMs) {
         final long realtimeUs = elapsedRealtime() * 1000;
@@ -189,7 +195,12 @@ public class BatteryUsageStatsProvider {
             }
 
             BatteryStatsImpl batteryStatsImpl = (BatteryStatsImpl) mStats;
-            batteryUsageStatsBuilder.setBatteryHistory(batteryStatsImpl.mHistoryBuffer);
+
+            // Make a copy of battery history to avoid concurrent modification.
+            Parcel historyBuffer = Parcel.obtain();
+            historyBuffer.appendFrom(batteryStatsImpl.mHistoryBuffer, 0,
+                    batteryStatsImpl.mHistoryBuffer.dataSize());
+            batteryUsageStatsBuilder.setBatteryHistory(historyBuffer);
         }
 
         return batteryUsageStatsBuilder.build();