Make BatteryDatabaseManager singleton

In BatteryTipLoader, two threads may access BatteryDatabaseManager
simultaneously. In this case thread A may close the database thread B
holds, then settings will crash.

In this cl, we make the BatteryDatabaseManager as singleton and
synchronize all the database related method. Then it shouldn't have
the crash anymore.

Bug: 73346734
Test: RunSettingsRoboTests
Change-Id: Ib53b2894b25155cca0c6ec60d1a816663d27a578

src/com/android/settings/fuelgauge/batterytip/BatteryDatabaseManager.java

@@ -38,14 +38,26 @@ import java.util.List;
 
 /**
  * Database manager for battery data. Now it only contains anomaly data stored in {@link AppInfo}.
+ *
+ * This manager may be accessed by multi-threads. All the database related methods are synchronized
+ * so each operation won't be interfered by other threads.
  */
 public class BatteryDatabaseManager {
-    private final AnomalyDatabaseHelper mDatabaseHelper;
+    private static BatteryDatabaseManager sSingleton;
 
-    public BatteryDatabaseManager(Context context) {
+    private AnomalyDatabaseHelper mDatabaseHelper;
+
+    private BatteryDatabaseManager(Context context) {
         mDatabaseHelper = AnomalyDatabaseHelper.getInstance(context);
     }
 
+    public static BatteryDatabaseManager getInstance(Context context) {
+        if (sSingleton == null) {
+            sSingleton = new BatteryDatabaseManager(context);
+        }
+        return sSingleton;
+    }
+
     /**
      * Insert an anomaly log to database.
      *
@@ -53,7 +65,7 @@ public class BatteryDatabaseManager {
      * @param type        the type of the anomaly
      * @param timestampMs the time when it is happened
      */
-    public void insertAnomaly(String packageName, int type, long timestampMs) {
+    public synchronized void insertAnomaly(String packageName, int type, long timestampMs) {
         try (SQLiteDatabase db = mDatabaseHelper.getWritableDatabase()) {
             ContentValues values = new ContentValues();
             values.put(PACKAGE_NAME, packageName);
@@ -67,7 +79,7 @@ public class BatteryDatabaseManager {
     /**
      * Query all the anomalies that happened after {@code timestampMsAfter} and with {@code state}.
      */
-    public List<AppInfo> queryAllAnomalies(long timestampMsAfter, int state) {
+    public synchronized List<AppInfo> queryAllAnomalies(long timestampMsAfter, int state) {
         final List<AppInfo> appInfos = new ArrayList<>();
         try (SQLiteDatabase db = mDatabaseHelper.getReadableDatabase()) {
             final String[] projection = {PACKAGE_NAME, ANOMALY_TYPE};
@@ -90,7 +102,7 @@ public class BatteryDatabaseManager {
         return appInfos;
     }
 
-    public void deleteAllAnomaliesBeforeTimeStamp(long timestampMs) {
+    public synchronized void deleteAllAnomaliesBeforeTimeStamp(long timestampMs) {
         try (SQLiteDatabase db = mDatabaseHelper.getWritableDatabase()) {
             db.delete(TABLE_ANOMALY, TIME_STAMP_MS + " < ?",
                     new String[]{String.valueOf(timestampMs)});
@@ -103,7 +115,7 @@ public class BatteryDatabaseManager {
      * @param appInfos represents the anomalies
      * @param state    which state to update to
      */
-    public void updateAnomalies(List<AppInfo> appInfos, int state) {
+    public synchronized void updateAnomalies(List<AppInfo> appInfos, int state) {
         if (!appInfos.isEmpty()) {
             final int size = appInfos.size();
             final String[] whereArgs = new String[size];

src/com/android/settings/fuelgauge/batterytip/actions/RestrictAppAction.java

@@ -42,7 +42,7 @@ public class RestrictAppAction extends BatteryTipAction {
         super(context);
         mRestrictAppTip = tip;
         mBatteryUtils = BatteryUtils.getInstance(context);
-        mBatteryDatabaseManager = new BatteryDatabaseManager(context);
+        mBatteryDatabaseManager = BatteryDatabaseManager.getInstance(context);
     }
 
     /**

src/com/android/settings/fuelgauge/batterytip/detectors/RestrictAppDetector.java

@@ -43,7 +43,7 @@ public class RestrictAppDetector implements BatteryTipDetector {
 
     public RestrictAppDetector(Context context, BatteryTipPolicy policy) {
         mPolicy = policy;
-        mBatteryDatabaseManager = new BatteryDatabaseManager(context);
+        mBatteryDatabaseManager = BatteryDatabaseManager.getInstance(context);
     }
 
     @Override

tests/robotests/src/com/android/settings/fuelgauge/BatteryDatabaseManagerTest.java

@@ -59,7 +59,7 @@ public class BatteryDatabaseManagerTest {
         MockitoAnnotations.initMocks(this);
 
         mContext = RuntimeEnvironment.application;
-        mBatteryDatabaseManager = spy(new BatteryDatabaseManager(mContext));
+        mBatteryDatabaseManager = spy(BatteryDatabaseManager.getInstance(mContext));
     }
 
     @After

tests/robotests/src/com/android/settings/testutils/DatabaseTestUtils.java

@@ -19,6 +19,7 @@ package com.android.settings.testutils;
 import android.content.Context;
 
 import com.android.settings.fuelgauge.batterytip.AnomalyDatabaseHelper;
+import com.android.settings.fuelgauge.batterytip.BatteryDatabaseManager;
 import com.android.settings.search.IndexDatabaseHelper;
 import com.android.settings.slices.SlicesDatabaseHelper;
 
@@ -30,6 +31,7 @@ public class DatabaseTestUtils {
         clearSearchDb(context);
         clearSlicesDb(context);
         clearAnomalyDb(context);
+        clearAnomalyDbManager();
     }
 
     private static void clearSlicesDb(Context context) {
@@ -76,4 +78,16 @@ public class DatabaseTestUtils {
             throw new RuntimeException();
         }
     }
+
+    private static void clearAnomalyDbManager() {
+        Field instance;
+        Class clazz = BatteryDatabaseManager.class;
+        try {
+            instance = clazz.getDeclaredField("sSingleton");
+            instance.setAccessible(true);
+            instance.set(null, null);
+        } catch (Exception e) {
+            throw new RuntimeException();
+        }
+    }
 }