content: package com.android.launcher3.util;
  
  import android.content.ContentValues;
  import android.content.Context;
  import android.database.Cursor;
  import android.database.sqlite.SQLiteDatabase;
  import android.database.sqlite.SQLiteException;
  import android.database.sqlite.SQLiteFullException;
  import android.database.sqlite.SQLiteOpenHelper;
  import android.util.Log;
  
  import com.android.launcher3.Utilities;
  import com.android.launcher3.config.FeatureFlags;
  
  /**
   * An extension of {@link SQLiteOpenHelper} with utility methods for a single table cache DB.
   * Any exception during write operations are ignored, and any version change causes a DB reset.
   */
  public abstract class SQLiteCacheHelper {
      private static final String TAG = "SQLiteCacheHelper";
  
      private static final boolean NO_ICON_CACHE = FeatureFlags.IS_DOGFOOD_BUILD &&
              Utilities.isPropertyEnabled(LogConfig.MEMORY_ONLY_ICON_CACHE);
  
      private final String mTableName;
      private final MySQLiteOpenHelper mOpenHelper;
  
      private boolean mIgnoreWrites;
  
      public SQLiteCacheHelper(Context context, String name, int version, String tableName) {
          if (NO_ICON_CACHE) {
              name = null;
          }
          mTableName = tableName;
          mOpenHelper = new MySQLiteOpenHelper(context, name, version);
  
          mIgnoreWrites = false;
      }
  
      /**
       * @see SQLiteDatabase#delete(String, String, String[])
       */
      public void delete(String whereClause, String[] whereArgs) {
          if (mIgnoreWrites) {
              return;
          }
          try {
              mOpenHelper.getWritableDatabase().delete(mTableName, whereClause, whereArgs);
          } catch (SQLiteFullException e) {
              onDiskFull(e);
          } catch (SQLiteException e) {
              Log.d(TAG, "Ignoring sqlite exception", e);
          }
      }
  
      /**
       * @see SQLiteDatabase#insertWithOnConflict(String, String, ContentValues, int)
       */
      public void insertOrReplace(ContentValues values) {
          if (mIgnoreWrites) {
              return;
          }
          try {
              mOpenHelper.getWritableDatabase().insertWithOnConflict(
                      mTableName, null, values, SQLiteDatabase.CONFLICT_REPLACE);
          } catch (SQLiteFullException e) {
              onDiskFull(e);
          } catch (SQLiteException e) {
              Log.d(TAG, "Ignoring sqlite exception", e);
          }
      }
  
      private void onDiskFull(SQLiteFullException e) {
          Log.e(TAG, "Disk full, all write operations will be ignored", e);
          mIgnoreWrites = true;
      }
  
      /**
       * @see SQLiteDatabase#query(String, String[], String, String[], String, String, String)
       */
      public Cursor query(String[] columns, String selection, String[] selectionArgs) {
          return mOpenHelper.getReadableDatabase().query(
                  mTableName, columns, selection, selectionArgs, null, null, null);
      }
  
      public void clear() {
          mOpenHelper.clearDB(mOpenHelper.getWritableDatabase());
      }
  
      protected abstract void onCreateTable(SQLiteDatabase db);
  
      /**
       * A private inner class to prevent direct DB access.
       */
      private class MySQLiteOpenHelper extends SQLiteOpenHelper {
  
          public MySQLiteOpenHelper(Context context, String name, int version) {
              super(new NoLocaleSqliteContext(context), name, null, version);
          }
  
          @Override
          public void onCreate(SQLiteDatabase db) {
              onCreateTable(db);
          }
  
          @Override
          public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
              if (oldVersion != newVersion) {
                  clearDB(db);
              }
          }
  
          @Override
          public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
              if (oldVersion != newVersion) {
                  clearDB(db);
              }
          }
  
          private void clearDB(SQLiteDatabase db) {
              db.execSQL("DROP TABLE IF EXISTS " + mTableName);
              onCreate(db);
          }
      }
  }
  