1 files changed, 135 insertions, 0 deletions
diff --git a/src/com/android/launcher3/model/GridBackupTable.java b/src/com/android/launcher3/model/GridBackupTable.java
new file mode 100644
index 000000000..804a04019
--- /dev/null
+++ b/src/com/android/launcher3/model/GridBackupTable.java
@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.launcher3.model;
+
+import static com.android.launcher3.LauncherSettings.Favorites.BACKUP_TABLE_NAME;
+import static com.android.launcher3.provider.LauncherDbUtils.dropTable;
+import static com.android.launcher3.provider.LauncherDbUtils.tableExists;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.graphics.Point;
+import android.os.Process;
+import android.util.Log;
+
+import com.android.launcher3.LauncherSettings.Favorites;
+import com.android.launcher3.LauncherSettings.Settings;
+import com.android.launcher3.compat.UserManagerCompat;
+
+/**
+ * Helper class to backup and restore Favorites table into a separate table
+ * within the same data base.
+ */
+public class GridBackupTable {
+    private static final String TAG = "GridBackupTable";
+
+    private static final int ID_PROPERTY = -1;
+
+    private static final String KEY_HOTSEAT_SIZE = Favorites.SCREEN;
+    private static final String KEY_GRID_X_SIZE = Favorites.SPANX;
+    private static final String KEY_GRID_Y_SIZE = Favorites.SPANY;
+    private static final String KEY_DB_VERSION = Favorites.RANK;
+
+    private final Context mContext;
+    private final SQLiteDatabase mDb;
+
+    private final int mOldHotseatSize;
+    private final int mOldGridX;
+    private final int mOldGridY;
+
+    private int mRestoredHotseatSize;
+    private int mRestoredGridX;
+    private int mRestoredGridY;
+
+    public GridBackupTable(Context context, SQLiteDatabase db,
+            int hotseatSize, int gridX, int gridY) {
+        mContext = context;
+        mDb = db;
+
+        mOldHotseatSize = hotseatSize;
+        mOldGridX = gridX;
+        mOldGridY = gridY;
+    }
+
+    public boolean backupOrRestoreAsNeeded() {
+        // Check if backup table exists
+        if (!tableExists(mDb, BACKUP_TABLE_NAME)) {
+            if (Settings.call(mContext.getContentResolver(), Settings.METHOD_WAS_EMPTY_DB_CREATED)
+                    .getBoolean(Settings.EXTRA_VALUE, false)) {
+                // No need to copy if empty DB was created.
+                return false;
+            }
+
+            copyTable(Favorites.TABLE_NAME, BACKUP_TABLE_NAME);
+            encodeDBProperties();
+            return false;
+        }
+
+        if (!loadDbProperties()) {
+            return false;
+        }
+        copyTable(BACKUP_TABLE_NAME, Favorites.TABLE_NAME);
+        Log.d(TAG, "Backup table found");
+        return true;
+    }
+
+    public int getRestoreHotseatAndGridSize(Point outGridSize) {
+        outGridSize.set(mRestoredGridX, mRestoredGridY);
+        return mRestoredHotseatSize;
+    }
+
+    private void copyTable(String from, String to) {
+        long userSerial = UserManagerCompat.getInstance(mContext).getSerialNumberForUser(
+                Process.myUserHandle());
+        dropTable(mDb, to);
+        Favorites.addTableToDb(mDb, userSerial, false, to);
+        mDb.execSQL("INSERT INTO " + to + " SELECT * FROM " + from + " where _id > " + ID_PROPERTY);
+    }
+
+    private void encodeDBProperties() {
+        ContentValues values = new ContentValues();
+        values.put(Favorites._ID, ID_PROPERTY);
+        values.put(KEY_DB_VERSION, mDb.getVersion());
+        values.put(KEY_GRID_X_SIZE, mOldGridX);
+        values.put(KEY_GRID_Y_SIZE, mOldGridY);
+        values.put(KEY_HOTSEAT_SIZE, mOldHotseatSize);
+        mDb.insert(BACKUP_TABLE_NAME, null, values);
+    }
+
+    private boolean loadDbProperties() {
+        try (Cursor c = mDb.query(BACKUP_TABLE_NAME, new String[] {
+                        KEY_DB_VERSION,     // 0
+                        KEY_GRID_X_SIZE,    // 1
+                        KEY_GRID_Y_SIZE,    // 2
+                        KEY_HOTSEAT_SIZE},  // 3
+                "_id=" + ID_PROPERTY, null, null, null, null)) {
+            if (!c.moveToNext()) {
+                Log.e(TAG, "Meta data not found in backup table");
+                return false;
+            }
+            if (mDb.getVersion() != c.getInt(0)) {
+                return false;
+            }
+
+            mRestoredGridX = c.getInt(1);
+            mRestoredGridY = c.getInt(2);
+            mRestoredHotseatSize = c.getInt(3);
+            return true;
+        }
+    }
+}