| /* |
| * Copyright (C) 2016 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.wallpaperbackup; |
| |
| import android.app.WallpaperManager; |
| import android.app.backup.BackupAgent; |
| import android.app.backup.BackupDataInput; |
| import android.app.backup.BackupDataOutput; |
| import android.app.backup.FullBackupDataOutput; |
| import android.content.Context; |
| import android.graphics.Rect; |
| import android.os.Environment; |
| import android.os.ParcelFileDescriptor; |
| import android.os.UserHandle; |
| import android.system.Os; |
| import android.util.Slog; |
| import android.util.Xml; |
| |
| import org.xmlpull.v1.XmlPullParser; |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| import java.nio.charset.StandardCharsets; |
| |
| public class WallpaperBackupAgent extends BackupAgent { |
| private static final String TAG = "WallpaperBackup"; |
| private static final boolean DEBUG = false; |
| |
| // NB: must be kept in sync with WallpaperManagerService but has no |
| // compile-time visibility. |
| |
| // Target filenames within the system's wallpaper directory |
| static final String WALLPAPER = "wallpaper_orig"; |
| static final String WALLPAPER_INFO = "wallpaper_info.xml"; |
| |
| // Names of our local-data stage files/links |
| static final String IMAGE_STAGE = "wallpaper-stage"; |
| static final String INFO_STAGE = "wallpaper-info-stage"; |
| static final String EMPTY_SENTINEL = "empty"; |
| |
| private File mWallpaperInfo; // wallpaper metadata file |
| private File mWallpaperFile; // primary wallpaper image file |
| |
| private WallpaperManager mWm; |
| |
| @Override |
| public void onCreate() { |
| if (DEBUG) { |
| Slog.v(TAG, "onCreate()"); |
| } |
| |
| File wallpaperDir = Environment.getUserSystemDirectory(UserHandle.USER_SYSTEM); |
| mWallpaperInfo = new File(wallpaperDir, WALLPAPER_INFO); |
| mWallpaperFile = new File(wallpaperDir, WALLPAPER); |
| mWm = (WallpaperManager) getSystemService(Context.WALLPAPER_SERVICE); |
| } |
| |
| @Override |
| public void onFullBackup(FullBackupDataOutput data) throws IOException { |
| // To avoid data duplication and disk churn, use links as the stage. |
| final File filesDir = getFilesDir(); |
| final File infoStage = new File(filesDir, INFO_STAGE); |
| final File imageStage = new File (filesDir, IMAGE_STAGE); |
| final File empty = new File (filesDir, EMPTY_SENTINEL); |
| |
| try { |
| // We always back up this 'empty' file to ensure that the absence of |
| // storable wallpaper imagery still produces a non-empty backup data |
| // stream, otherwise it'd simply be ignored in preflight. |
| FileOutputStream touch = new FileOutputStream(empty); |
| touch.close(); |
| fullBackupFile(empty, data); |
| |
| // only back up the wallpaper if we've been told it's allowed |
| if (mWm.isWallpaperBackupEligible()) { |
| if (DEBUG) { |
| Slog.v(TAG, "Wallpaper is backup-eligible; linking & writing"); |
| } |
| Os.link(mWallpaperInfo.getCanonicalPath(), infoStage.getCanonicalPath()); |
| fullBackupFile(infoStage, data); |
| Os.link(mWallpaperFile.getCanonicalPath(), imageStage.getCanonicalPath()); |
| fullBackupFile(imageStage, data); |
| } else { |
| if (DEBUG) { |
| Slog.v(TAG, "Wallpaper not backup-eligible; writing no data"); |
| } |
| } |
| } catch (Exception e) { |
| Slog.e(TAG, "Unable to back up wallpaper: " + e.getMessage()); |
| } finally { |
| if (DEBUG) { |
| Slog.v(TAG, "Removing backup stage links"); |
| } |
| infoStage.delete(); |
| imageStage.delete(); |
| } |
| } |
| |
| // We use the default onRestoreFile() implementation that will recreate our stage files, |
| // then post-process in onRestoreFinished() to apply the new wallpaper. |
| @Override |
| public void onRestoreFinished() { |
| if (DEBUG) { |
| Slog.v(TAG, "onRestoreFinished()"); |
| } |
| final File infoStage = new File(getFilesDir(), INFO_STAGE); |
| final File imageStage = new File (getFilesDir(), IMAGE_STAGE); |
| |
| try { |
| // It is valid for the imagery to be absent; it means that we were not permitted |
| // to back up the original image on the source device. |
| if (imageStage.exists()) { |
| if (DEBUG) { |
| Slog.v(TAG, "Got restored wallpaper; applying"); |
| } |
| |
| // Parse the restored info file to find the crop hint. Note that this currently |
| // relies on a priori knowledge of the wallpaper info file schema. |
| Rect cropHint = parseCropHint(infoStage); |
| if (cropHint != null) { |
| if (DEBUG) { |
| Slog.v(TAG, "Restored crop hint " + cropHint + "; now writing data"); |
| } |
| WallpaperManager wm = getSystemService(WallpaperManager.class); |
| try (FileInputStream in = new FileInputStream(imageStage)) { |
| wm.setStream(in, cropHint, true, WallpaperManager.FLAG_SYSTEM); |
| } finally {} // auto-closes 'in' |
| } |
| } |
| } catch (Exception e) { |
| Slog.e(TAG, "Unable to restore wallpaper: " + e.getMessage()); |
| } finally { |
| if (DEBUG) { |
| Slog.v(TAG, "Removing restore stage files"); |
| } |
| infoStage.delete(); |
| imageStage.delete(); |
| } |
| } |
| |
| private Rect parseCropHint(File wallpaperInfo) { |
| Rect cropHint = new Rect(); |
| try (FileInputStream stream = new FileInputStream(wallpaperInfo)) { |
| XmlPullParser parser = Xml.newPullParser(); |
| parser.setInput(stream, StandardCharsets.UTF_8.name()); |
| |
| int type; |
| do { |
| type = parser.next(); |
| if (type == XmlPullParser.START_TAG) { |
| String tag = parser.getName(); |
| if ("wp".equals(tag)) { |
| cropHint.left = getAttributeInt(parser, "cropLeft", 0); |
| cropHint.top = getAttributeInt(parser, "cropTop", 0); |
| cropHint.right = getAttributeInt(parser, "cropRight", 0); |
| cropHint.bottom = getAttributeInt(parser, "cropBottom", 0); |
| } |
| } |
| } while (type != XmlPullParser.END_DOCUMENT); |
| } catch (Exception e) { |
| // Whoops; can't process the info file at all. Report failure. |
| Slog.w(TAG, "Failed to parse restored metadata: " + e.getMessage()); |
| return null; |
| } |
| |
| return cropHint; |
| } |
| |
| private int getAttributeInt(XmlPullParser parser, String name, int defValue) { |
| final String value = parser.getAttributeValue(null, name); |
| return (value == null) ? defValue : Integer.parseInt(value); |
| } |
| |
| // |
| // Key/value API: abstract, therefore required; but not used |
| // |
| |
| @Override |
| public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data, |
| ParcelFileDescriptor newState) throws IOException { |
| // Intentionally blank |
| } |
| |
| @Override |
| public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState) |
| throws IOException { |
| // Intentionally blank |
| } |
| } |