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Commit 05f30889 authored by Sunny Goyal's avatar Sunny Goyal
Browse files

Adding support for DB downgrade 

Adding a schema file for handling DB downgrade. This schema file is part of
the backup/restore set, and hence is available on a device with lower app version.

Bug: 37257575
Change-Id: I69c8ef5f28d5209be6e6679412c7459d4eeda5d0
parent 07557e81

res/raw/downgrade_schema.json

0 → 100644
+20 −0
Original line number Diff line number Diff line 
{

  // Note: Comments are not supported in JSON schema, but android parser is lenient.



  // Maximum DB version supported by this schema

  "version" : 27,



  // Downgrade from 27 to 26. Empty array indicates, the DB is compatible

  "downgrade_to_26" : [],

  "downgrade_to_25" : [],

  "downgrade_to_24" : [],

  "downgrade_to_23" : [],

  "downgrade_to_22" : [

    "ALTER TABLE favorites RENAME TO temp_favorites;",

    "CREATE TABLE favorites(_id INTEGER PRIMARY KEY, title TEXT, intent TEXT, container INTEGER, screen INTEGER, cellX INTEGER, cellY INTEGER, spanX INTEGER, spanY INTEGER, itemType INTEGER, appWidgetId INTEGER NOT NULL DEFAULT - 1, iconPackage TEXT, iconResource TEXT, icon BLOB, appWidgetProvider TEXT, modified INTEGER NOT NULL DEFAULT 0, restored INTEGER NOT NULL DEFAULT 0, profileId INTEGER DEFAULT 0, rank INTEGER NOT NULL DEFAULT 0);",

    "INSERT INTO favorites SELECT _id, title, intent, container, screen, cellX, cellY, spanX, spanY, itemType, appWidgetId, iconPackage, iconResource, icon, appWidgetProvider, modified, restored, profileId, rank FROM temp_favorites;",

    "DROP TABLE temp_favorites;"

  ]



  // Missing values indicate the DB is not compatible

}
 
 No newline at end of file

res/xml/backupscheme.xml

+1 −0
Original line number Diff line number Diff line
@@ -3,5 +3,6 @@ 


    <include domain="database" path="launcher.db" />

    <include domain="sharedpref" path="com.android.launcher3.prefs.xml" />

    <include domain="file" path="downgrade_schema.json" />



</full-backup-content>
 
 No newline at end of file

src/com/android/launcher3/LauncherProvider.java

+31 −53
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ import com.android.launcher3.config.FeatureFlags; 
import com.android.launcher3.dynamicui.ExtractionUtils;

import com.android.launcher3.graphics.IconShapeOverride;

import com.android.launcher3.logging.FileLog;

import com.android.launcher3.model.DbDowngradeHelper;

import com.android.launcher3.provider.LauncherDbUtils;

import com.android.launcher3.provider.LauncherDbUtils.SQLiteTransaction;

import com.android.launcher3.provider.RestoreDbTask;
@@ -64,6 +65,7 @@ import com.android.launcher3.util.NoLocaleSqliteContext; 
import com.android.launcher3.util.Preconditions;

import com.android.launcher3.util.Thunk;



import java.io.File;

import java.io.FileDescriptor;

import java.io.PrintWriter;

import java.lang.reflect.Method;
@@ -77,18 +79,12 @@ public class LauncherProvider extends ContentProvider { 
    private static final String TAG = "LauncherProvider";

    private static final boolean LOGD = false;



    private static final String DOWNGRADE_SCHEMA_FILE = "downgrade_schema.json";



    /**

     * Represents the schema of the database. Changes in scheme need not be backwards compatible.

     */

    private static final int SCHEMA_VERSION = 27;

    /**

     * Represents the actual data. It could include additional validations and normalizations added

     * overtime. These must be backwards compatible, else we risk breaking old devices during

     * restore or binary version downgrade.

     */

    private static final int DATA_VERSION = 3;



    private static final String PREF_KEY_DATA_VERISON = "provider_data_version";

    public static final int SCHEMA_VERSION = 27;



    public static final String AUTHORITY = (BuildConfig.APPLICATION_ID + ".settings").intern();
@@ -703,34 +699,23 @@ public class LauncherProvider extends ContentProvider { 
        @Override

        public void onOpen(SQLiteDatabase db) {

            super.onOpen(db);

            SharedPreferences prefs = mContext

                    .getSharedPreferences(LauncherFiles.DEVICE_PREFERENCES_KEY, 0);

            int oldVersion = prefs.getInt(PREF_KEY_DATA_VERISON, 0);

            if (oldVersion != DATA_VERSION) {

                // Only run the data upgrade path for an existing db.

                if (!Utilities.getPrefs(mContext).getBoolean(EMPTY_DATABASE_CREATED, false)) {

                    try (SQLiteTransaction t = new SQLiteTransaction(db)) {

                        onDataUpgrade(db, oldVersion);

                        t.commit();

                    } catch (Exception e) {

                        Log.d(TAG, "Error updating data version, ignoring", e);

                        return;

                    }

                }

                prefs.edit().putInt(PREF_KEY_DATA_VERISON, DATA_VERSION).apply();



            File schemaFile = mContext.getFileStreamPath(DOWNGRADE_SCHEMA_FILE);

            if (!schemaFile.exists()) {

                handleOneTimeDataUpgrade(db);

            }

            DbDowngradeHelper.updateSchemaFile(schemaFile, SCHEMA_VERSION, mContext,

                    R.raw.downgrade_schema);

        }



        /**

         * Called when the data is updated as part of app update. It can be called multiple times

         * with old version, even though it had been run before. The changes made here must be

         * backwards compatible, else we risk breaking old devices during restore or binary

         * version downgrade.

         * One-time data updated before support of onDowngrade was added. This update is backwards

         * compatible and can safely be run multiple times.

         * Note: No new logic should be added here after release, as the new logic might not get

         * executed on an existing device.

         * TODO: Move this to db upgrade path, once the downgrade path is released.

         */

        protected void onDataUpgrade(SQLiteDatabase db, int oldVersion) {

            switch (oldVersion) {

                case 0:

                case 1: {

        protected void handleOneTimeDataUpgrade(SQLiteDatabase db) {

            // Remove "profile extra"

            UserManagerCompat um = UserManagerCompat.getInstance(mContext);

            for (UserHandle user : um.getUserProfiles()) {
@@ -740,12 +725,6 @@ public class LauncherProvider extends ContentProvider { 
                db.execSQL(sql);

            }

        }

                case 2:

                case 3:

                    // data updated

                    return;

            }

        }



        @Override

        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
@@ -850,16 +829,15 @@ public class LauncherProvider extends ContentProvider { 


        @Override

        public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {

            if (oldVersion == 28 && newVersion == 27) {

                // TODO: remove this check. This is only applicable for internal development/testing

                // and for any released version of Launcher.

                return;

            }

            // This shouldn't happen -- throw our hands up in the air and start over.

            Log.w(TAG, "Database version downgrade from: " + oldVersion + " to " + newVersion +

                    ". Wiping databse.");

            try {

                DbDowngradeHelper.parse(mContext.getFileStreamPath(DOWNGRADE_SCHEMA_FILE))

                        .onDowngrade(db, oldVersion, newVersion);

            } catch (Exception e) {

                Log.d(TAG, "Unable to downgrade from: " + oldVersion + " to " + newVersion +

                        ". Wiping databse.", e);

                createEmptyDB(db);

            }

        }



        /**

         * Clears all the data for a fresh start.

src/com/android/launcher3/model/DbDowngradeHelper.java

0 → 100644
+108 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 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 android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteException;

import android.util.Log;

import android.util.SparseArray;



import com.android.launcher3.provider.LauncherDbUtils.SQLiteTransaction;

import com.android.launcher3.util.IOUtils;



import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;



import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.Collections;



/**

 * Utility class to handle DB downgrade

 */

public class DbDowngradeHelper {



    private static final String TAG = "DbDowngradeHelper";



    private static final String KEY_VERSION = "version";

    private static final String KEY_DOWNGRADE_TO = "downgrade_to_";



    private final SparseArray<String[]> mStatements = new SparseArray<>();

    public final int version;



    private DbDowngradeHelper(int version) {

        this.version = version;

    }



    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        ArrayList<String> allCommands = new ArrayList<>();



        for (int i = oldVersion - 1; i >= newVersion; i--) {

            String[] commands = mStatements.get(i);

            if (commands == null) {

                throw new SQLiteException("Downgrade path not supported to version " + i);

            }

            Collections.addAll(allCommands, commands);

        }



        try (SQLiteTransaction t = new SQLiteTransaction(db)) {

            for (String sql : allCommands) {

                db.execSQL(sql);

            }

            t.commit();

        }

    }



    public static DbDowngradeHelper parse(File file) throws JSONException, IOException {

        JSONObject obj = new JSONObject(new String(IOUtils.toByteArray(file)));

        DbDowngradeHelper helper = new DbDowngradeHelper(obj.getInt(KEY_VERSION));

        for (int version = helper.version - 1; version > 0; version--) {

            if (obj.has(KEY_DOWNGRADE_TO + version)) {

                JSONArray statements = obj.getJSONArray(KEY_DOWNGRADE_TO + version);

                String[] parsed = new String[statements.length()];

                for (int i = 0; i < parsed.length; i++) {

                    parsed[i] = statements.getString(i);

                }

                helper.mStatements.put(version, parsed);

            }

        }

        return helper;

    }



    public static void updateSchemaFile(File schemaFile, int expectedVersion,

            Context context, int schemaResId) {

        try {

            if (DbDowngradeHelper.parse(schemaFile).version >= expectedVersion) {

                return;

            }

        } catch (Exception e) {

            // Schema error

        }



        // Write the updated schema

        try (FileOutputStream fos = new FileOutputStream(schemaFile);

            InputStream in = context.getResources().openRawResource(schemaResId)) {

            IOUtils.copy(in, fos);

        } catch (IOException e) {

            Log.e(TAG, "Error writing schema file", e);

        }

    }

}

src/com/android/launcher3/provider/LauncherDbUtils.java

+2 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ public class LauncherDbUtils { 


            if (screenIds.isEmpty()) {

                // No update needed

                t.commit();

                return true;

            }

            if (screenIds.get(0) != 0) {
@@ -71,6 +72,7 @@ public class LauncherDbUtils { 
            if (DatabaseUtils.queryNumEntries(db, Favorites.TABLE_NAME,

                    "container = -100 and screen = 0 and cellY = 0") == 0) {

                // First row is empty, no need to migrate.

                t.commit();

                return true;

            }