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.sqlite.SQLiteDatabase;
23 import android.util.Log;
24 
25 import com.android.launcher3.LauncherAppState;
26 import com.android.launcher3.LauncherSettings.Favorites;
27 import com.android.launcher3.LauncherSettings.WorkspaceScreens;
28 import com.android.launcher3.logging.FileLog;
29 
30 import java.util.ArrayList;
31 
32 /**
33  * A set of utility methods for Launcher DB used for DB updates and migration.
34  */
35 public class LauncherDbUtils {
36 
37     private static final String TAG = "LauncherDbUtils";
38 
39     /**
40      * Makes the first screen as screen 0 (if screen 0 already exists,
41      * renames it to some other number).
42      * If the first row of screen 0 is non empty, runs a 'lossy' GridMigrationTask to clear
43      * the first row. The items in the first screen are moved and resized but the carry-forward
44      * items are simply deleted.
45      */
prepareScreenZeroToHostQsb(Context context, SQLiteDatabase db)46     public static boolean prepareScreenZeroToHostQsb(Context context, SQLiteDatabase db) {
47         db.beginTransaction();
48         try {
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                 return true;
56             }
57             if (screenIds.get(0) != 0) {
58                 // First screen is not 0, we need to rename screens
59                 if (screenIds.indexOf(0L) > -1) {
60                     // There is already a screen 0. First rename it to a different screen.
61                     long newScreenId = 1;
62                     while (screenIds.indexOf(newScreenId) > -1) newScreenId++;
63                     renameScreen(db, 0, newScreenId);
64                 }
65 
66                 // Rename the first screen to 0.
67                 renameScreen(db, screenIds.get(0), 0);
68             }
69 
70             // Check if the first row is empty
71             try (Cursor c = db.query(Favorites.TABLE_NAME, null,
72                     "container = -100 and screen = 0 and cellY = 0", null, null, null, null)) {
73                 if (c.getCount() == 0) {
74                     // First row is empty, no need to migrate.
75                     return true;
76                 }
77             }
78 
79             new LossyScreenMigrationTask(context, LauncherAppState.getIDP(context), db)
80                     .migrateScreen0();
81             db.setTransactionSuccessful();
82             return true;
83         } catch (Exception e) {
84             Log.e(TAG, "Failed to update workspace size", e);
85             return false;
86         } finally {
87             db.endTransaction();
88         }
89     }
90 
renameScreen(SQLiteDatabase db, long oldScreen, long newScreen)91     private static void renameScreen(SQLiteDatabase db, long oldScreen, long newScreen) {
92         String[] whereParams = new String[] { Long.toString(oldScreen) };
93 
94         ContentValues values = new ContentValues();
95         values.put(WorkspaceScreens._ID, newScreen);
96         db.update(WorkspaceScreens.TABLE_NAME, values, "_id = ?", whereParams);
97 
98         values.clear();
99         values.put(Favorites.SCREEN, newScreen);
100         db.update(Favorites.TABLE_NAME, values, "container = -100 and screen = ?", whereParams);
101     }
102 
103     /**
104      * Parses the cursor containing workspace screens table and returns the list of screen IDs
105      */
getScreenIdsFromCursor(Cursor sc)106     public static ArrayList<Long> getScreenIdsFromCursor(Cursor sc) {
107         ArrayList<Long> screenIds = new ArrayList<Long>();
108         try {
109             final int idIndex = sc.getColumnIndexOrThrow(WorkspaceScreens._ID);
110             while (sc.moveToNext()) {
111                 try {
112                     screenIds.add(sc.getLong(idIndex));
113                 } catch (Exception e) {
114                     FileLog.d(TAG, "Invalid screen id", e);
115                 }
116             }
117         } finally {
118             sc.close();
119         }
120         return screenIds;
121     }
122 }
123