1 /* 2 * Copyright (C) 2010 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 android.app.backup; 18 19 import android.app.WallpaperManager; 20 import android.content.Context; 21 import android.graphics.BitmapFactory; 22 import android.graphics.Point; 23 import android.os.Environment; 24 import android.os.ParcelFileDescriptor; 25 import android.os.UserHandle; 26 import android.util.Slog; 27 import android.view.Display; 28 import android.view.WindowManager; 29 30 import java.io.File; 31 32 /** 33 * Helper for backing up / restoring wallpapers. Basically an AbsoluteFileBackupHelper, 34 * but with logic for deciding what to do with restored wallpaper images. 35 * 36 * @hide 37 */ 38 public class WallpaperBackupHelper extends FileBackupHelperBase implements BackupHelper { 39 private static final String TAG = "WallpaperBackupHelper"; 40 private static final boolean DEBUG = false; 41 42 // If 'true', then apply an acceptable-size heuristic at restore time, dropping back 43 // to the factory default wallpaper if the restored one differs "too much" from the 44 // device's preferred wallpaper image dimensions. 45 private static final boolean REJECT_OUTSIZED_RESTORE = true; 46 47 // When outsized restore rejection is enabled, this is the maximum ratio between the 48 // source and target image heights that will be permitted. The ratio is checked both 49 // ways (i.e. >= MAX, or <= 1/MAX) to validate restores from both largeer-than-target 50 // and smaller-than-target sources. 51 private static final double MAX_HEIGHT_RATIO = 1.35; 52 53 // The height ratio check when applying larger images on smaller screens is separate; 54 // in current policy we accept any such restore regardless of the relative dimensions. 55 private static final double MIN_HEIGHT_RATIO = 0; 56 57 // This path must match what the WallpaperManagerService uses 58 // TODO: Will need to change if backing up non-primary user's wallpaper 59 public static final String WALLPAPER_IMAGE = 60 new File(Environment.getUserSystemDirectory(UserHandle.USER_OWNER), 61 "wallpaper").getAbsolutePath(); 62 public static final String WALLPAPER_INFO = 63 new File(Environment.getUserSystemDirectory(UserHandle.USER_OWNER), 64 "wallpaper_info.xml").getAbsolutePath(); 65 // Use old keys to keep legacy data compatibility and avoid writing two wallpapers 66 public static final String WALLPAPER_IMAGE_KEY = 67 "/data/data/com.android.settings/files/wallpaper"; 68 public static final String WALLPAPER_INFO_KEY = "/data/system/wallpaper_info.xml"; 69 70 // Stage file - should be adjacent to the WALLPAPER_IMAGE location. The wallpapers 71 // will be saved to this file from the restore stream, then renamed to the proper 72 // location if it's deemed suitable. 73 // TODO: Will need to change if backing up non-primary user's wallpaper 74 private static final String STAGE_FILE = 75 new File(Environment.getUserSystemDirectory(UserHandle.USER_OWNER), 76 "wallpaper-tmp").getAbsolutePath(); 77 78 Context mContext; 79 String[] mFiles; 80 String[] mKeys; 81 double mDesiredMinWidth; 82 double mDesiredMinHeight; 83 84 /** 85 * Construct a helper for backing up / restoring the files at the given absolute locations 86 * within the file system. 87 * 88 * @param context 89 * @param files 90 */ 91 public WallpaperBackupHelper(Context context, String[] files, String[] keys) { 92 super(context); 93 94 mContext = context; 95 mFiles = files; 96 mKeys = keys; 97 98 final WindowManager wm = 99 (WindowManager) context.getSystemService(Context.WINDOW_SERVICE); 100 final WallpaperManager wpm = 101 (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE); 102 final Display d = wm.getDefaultDisplay(); 103 final Point size = new Point(); 104 d.getSize(size); 105 mDesiredMinWidth = size.x; 106 mDesiredMinHeight = (double) wpm.getDesiredMinimumHeight(); 107 108 if (mDesiredMinHeight <= 0) { 109 mDesiredMinHeight = size.y; 110 } 111 112 if (DEBUG) { 113 Slog.d(TAG, "dmW=" + mDesiredMinWidth + " dmH=" + mDesiredMinHeight); 114 } 115 } 116 117 /** 118 * Based on oldState, determine which of the files from the application's data directory 119 * need to be backed up, write them to the data stream, and fill in newState with the 120 * state as it exists now. 121 */ 122 public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 123 ParcelFileDescriptor newState) { 124 performBackup_checked(oldState, data, newState, mFiles, mKeys); 125 } 126 127 /** 128 * Restore one absolute file entity from the restore stream. If we're restoring the 129 * magic wallpaper file, take specific action to determine whether it is suitable for 130 * the current device. 131 */ 132 public void restoreEntity(BackupDataInputStream data) { 133 final String key = data.getKey(); 134 if (isKeyInList(key, mKeys)) { 135 if (key.equals(WALLPAPER_IMAGE_KEY)) { 136 // restore the file to the stage for inspection 137 File f = new File(STAGE_FILE); 138 if (writeFile(f, data)) { 139 140 // Preflight the restored image's dimensions without loading it 141 BitmapFactory.Options options = new BitmapFactory.Options(); 142 options.inJustDecodeBounds = true; 143 BitmapFactory.decodeFile(STAGE_FILE, options); 144 145 if (DEBUG) Slog.d(TAG, "Restoring wallpaper image w=" + options.outWidth 146 + " h=" + options.outHeight); 147 148 if (REJECT_OUTSIZED_RESTORE) { 149 // We accept any wallpaper that is at least as wide as our preference 150 // (i.e. wide enough to fill the screen), and is within a comfortable 151 // factor of the target height, to avoid significant clipping/scaling/ 152 // letterboxing. 153 final double heightRatio = mDesiredMinHeight / options.outHeight; 154 if (options.outWidth < mDesiredMinWidth 155 || heightRatio >= MAX_HEIGHT_RATIO 156 || heightRatio <= MIN_HEIGHT_RATIO) { 157 // Not wide enough for the screen, or too short/tall to be a good fit 158 // for the height of the screen, broken image file, or the system's 159 // desires for wallpaper size are in a bad state. Probably one of the 160 // first two. 161 Slog.i(TAG, "Restored image dimensions (w=" 162 + options.outWidth + ", h=" + options.outHeight 163 + ") too far off target (tw=" 164 + mDesiredMinWidth + ", th=" + mDesiredMinHeight 165 + "); falling back to default wallpaper."); 166 f.delete(); 167 return; 168 } 169 } 170 171 // We passed the acceptable-dimensions test (if any), so we're going to 172 // use the restored image. 173 // TODO: spin a service to copy the restored image to sd/usb storage, 174 // since it does not exist anywhere other than the private wallpaper 175 // file. 176 Slog.d(TAG, "Applying restored wallpaper image."); 177 f.renameTo(new File(WALLPAPER_IMAGE)); 178 } 179 } else if (key.equals(WALLPAPER_INFO_KEY)) { 180 // XML file containing wallpaper info 181 File f = new File(WALLPAPER_INFO); 182 writeFile(f, data); 183 } 184 } 185 } 186 } 187
