Home | History | Annotate | Download | only in tv 
      1 /*
      2  * Copyright (C) 2017 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.providers.tv;
     18 
     19 import android.content.Context;
     20 import android.content.SharedPreferences;
     21 import android.database.sqlite.SQLiteDatabase;
     22 import android.media.tv.TvContract.Channels;
     23 import android.media.tv.TvContract.PreviewPrograms;
     24 import android.media.tv.TvContract.WatchNextPrograms;
     25 import android.preference.PreferenceManager;
     26 import android.provider.Settings;
     27 
     28 import com.android.internal.annotations.VisibleForTesting;
     29 import com.android.providers.tv.TvProvider.DatabaseHelper;
     30 
     31 /**
     32  * Convenient class for deleting transient rows. This ensures that the clean up job is done only
     33  * once after boot.
     34  */
     35 public class TransientRowHelper {
     36     private static final String PREF_KEY_LAST_DELETION_BOOT_COUNT =
     37             "pref_key_last_deletion_boot_count";
     38     private static TransientRowHelper sInstance;
     39 
     40     private Context mContext;
     41     private DatabaseHelper mDatabaseHelper;
     42     @VisibleForTesting
     43     protected boolean mTransientRowsDeleted;
     44 
     45     /**
     46      * Returns the singleton TransientRowHelper instance.
     47      *
     48      * @param context The application context.
     49      */
     50     public static TransientRowHelper getInstance(Context context) {
     51         synchronized (TransientRowHelper.class) {
     52             if (sInstance == null) {
     53                 sInstance = new TransientRowHelper(context);
     54             }
     55         }
     56         return sInstance;
     57     }
     58 
     59     @VisibleForTesting
     60     TransientRowHelper(Context context) {
     61         mContext = context;
     62         mDatabaseHelper = DatabaseHelper.getInstance(context);
     63     }
     64 
     65     /**
     66      * Ensures that transient rows, inserted previously before current boot, are deleted.
     67      */
     68     public synchronized void ensureOldTransientRowsDeleted() {
     69         if (mTransientRowsDeleted) {
     70             return;
     71         }
     72         mTransientRowsDeleted = true;
     73         if (getLastDeletionBootCount() >= getBootCount()) {
     74             // This can be the second execution of TvProvider after boot since system kills
     75             // TvProvider in low memory conditions. If this is the case, we shouldn't delete
     76             // transient rows.
     77             return;
     78         }
     79         SQLiteDatabase db = mDatabaseHelper.getWritableDatabase();
     80         // Delete all the transient programs and channels.
     81         db.delete(TvProvider.PREVIEW_PROGRAMS_TABLE, PreviewPrograms.COLUMN_TRANSIENT + "=1", null);
     82         db.delete(TvProvider.CHANNELS_TABLE, Channels.COLUMN_TRANSIENT + "=1", null);
     83         db.delete(TvProvider.WATCH_NEXT_PROGRAMS_TABLE, WatchNextPrograms.COLUMN_TRANSIENT + "=1",
     84                 null);
     85         setLastDeletionBootCount();
     86     }
     87 
     88     @VisibleForTesting
     89     protected int getBootCount() {
     90         return Settings.Global.getInt(mContext.getContentResolver(), Settings.Global.BOOT_COUNT,
     91                 -1);
     92     }
     93 
     94     @VisibleForTesting
     95     protected int getLastDeletionBootCount() {
     96         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
     97         return prefs.getInt(PREF_KEY_LAST_DELETION_BOOT_COUNT, -1);
     98     }
     99 
    100     @VisibleForTesting
    101     protected void setLastDeletionBootCount() {
    102         SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(mContext)
    103                 .edit();
    104         editor.putInt(PREF_KEY_LAST_DELETION_BOOT_COUNT, getBootCount());
    105         editor.apply();
    106     }
    107 }
    108