Home | History | Annotate | Download | only in provider 
      1 /*
      2  * Copyright (C) 2016 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.launcher3.provider;
     18 
     19 import android.content.ContentValues;
     20 import android.content.Context;
     21 import android.database.Cursor;
     22 import android.database.DatabaseUtils;
     23 import android.database.sqlite.SQLiteDatabase;
     24 import android.util.Log;
     25 
     26 import com.android.launcher3.LauncherAppState;
     27 import com.android.launcher3.LauncherSettings.Favorites;
     28 import com.android.launcher3.LauncherSettings.WorkspaceScreens;
     29 
     30 import java.util.ArrayList;
     31 import java.util.Collection;
     32 
     33 /**
     34  * A set of utility methods for Launcher DB used for DB updates and migration.
     35  */
     36 public class LauncherDbUtils {
     37 
     38     private static final String TAG = "LauncherDbUtils";
     39 
     40     /**
     41      * Makes the first screen as screen 0 (if screen 0 already exists,
     42      * renames it to some other number).
     43      * If the first row of screen 0 is non empty, runs a 'lossy' GridMigrationTask to clear
     44      * the first row. The items in the first screen are moved and resized but the carry-forward
     45      * items are simply deleted.
     46      */
     47     public static boolean prepareScreenZeroToHostQsb(Context context, SQLiteDatabase db) {
     48         try (SQLiteTransaction t = new SQLiteTransaction(db)) {
     49             // Get the existing screens
     50             ArrayList<Long> screenIds = getScreenIdsFromCursor(db.query(WorkspaceScreens.TABLE_NAME,
     51                     null, null, null, null, null, WorkspaceScreens.SCREEN_RANK));
     52 
     53             if (screenIds.isEmpty()) {
     54                 // No update needed
     55                 t.commit();
     56                 return true;
     57             }
     58             if (screenIds.get(0) != 0) {
     59                 // First screen is not 0, we need to rename screens
     60                 if (screenIds.indexOf(0L) > -1) {
     61                     // There is already a screen 0. First rename it to a different screen.
     62                     long newScreenId = 1;
     63                     while (screenIds.indexOf(newScreenId) > -1) newScreenId++;
     64                     renameScreen(db, 0, newScreenId);
     65                 }
     66 
     67                 // Rename the first screen to 0.
     68                 renameScreen(db, screenIds.get(0), 0);
     69             }
     70 
     71             // Check if the first row is empty
     72             if (DatabaseUtils.queryNumEntries(db, Favorites.TABLE_NAME,
     73                     "container = -100 and screen = 0 and cellY = 0") == 0) {
     74                 // First row is empty, no need to migrate.
     75                 t.commit();
     76                 return true;
     77             }
     78 
     79             new LossyScreenMigrationTask(context, LauncherAppState.getIDP(context), db)
     80                     .migrateScreen0();
     81             t.commit();
     82             return true;
     83         } catch (Exception e) {
     84             Log.e(TAG, "Failed to update workspace size", e);
     85             return false;
     86         }
     87     }
     88 
     89     private static void renameScreen(SQLiteDatabase db, long oldScreen, long newScreen) {
     90         String[] whereParams = new String[] { Long.toString(oldScreen) };
     91 
     92         ContentValues values = new ContentValues();
     93         values.put(WorkspaceScreens._ID, newScreen);
     94         db.update(WorkspaceScreens.TABLE_NAME, values, "_id = ?", whereParams);
     95 
     96         values.clear();
     97         values.put(Favorites.SCREEN, newScreen);
     98         db.update(Favorites.TABLE_NAME, values, "container = -100 and screen = ?", whereParams);
     99     }
    100 
    101     /**
    102      * Parses the cursor containing workspace screens table and returns the list of screen IDs
    103      */
    104     public static ArrayList<Long> getScreenIdsFromCursor(Cursor sc) {
    105         try {
    106             return iterateCursor(sc,
    107                     sc.getColumnIndexOrThrow(WorkspaceScreens._ID),
    108                     new ArrayList<Long>());
    109         } finally {
    110             sc.close();
    111         }
    112     }
    113 
    114     public static <T extends Collection<Long>> T iterateCursor(Cursor c, int columnIndex, T out) {
    115         while (c.moveToNext()) {
    116             out.add(c.getLong(columnIndex));
    117         }
    118         return out;
    119     }
    120 
    121     /**
    122      * Utility class to simplify managing sqlite transactions
    123      */
    124     public static class SQLiteTransaction implements AutoCloseable {
    125         private final SQLiteDatabase mDb;
    126 
    127         public SQLiteTransaction(SQLiteDatabase db) {
    128             mDb = db;
    129             db.beginTransaction();
    130         }
    131 
    132         public void commit() {
    133             mDb.setTransactionSuccessful();
    134         }
    135 
    136         @Override
    137         public void close() {
    138             mDb.endTransaction();
    139         }
    140     }
    141 }
    142