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 = false; 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 // http://b/22388012 60 public static final String WALLPAPER_IMAGE = 61 new File(Environment.getUserSystemDirectory(UserHandle.USER_SYSTEM), 62 "wallpaper").getAbsolutePath(); 63 public static final String WALLPAPER_ORIG_IMAGE = 64 new File(Environment.getUserSystemDirectory(UserHandle.USER_SYSTEM), 65 "wallpaper_orig").getAbsolutePath(); 66 public static final String WALLPAPER_INFO = 67 new File(Environment.getUserSystemDirectory(UserHandle.USER_SYSTEM), 68 "wallpaper_info.xml").getAbsolutePath(); 69 // Use old keys to keep legacy data compatibility and avoid writing two wallpapers 70 public static final String WALLPAPER_IMAGE_KEY = 71 "/data/data/com.android.settings/files/wallpaper"; 72 public static final String WALLPAPER_INFO_KEY = "/data/system/wallpaper_info.xml"; 73 74 // Stage file - should be adjacent to the WALLPAPER_IMAGE location. The wallpapers 75 // will be saved to this file from the restore stream, then renamed to the proper 76 // location if it's deemed suitable. 77 // TODO: Will need to change if backing up non-primary user's wallpaper 78 // http://b/22388012 79 private static final String STAGE_FILE = 80 new File(Environment.getUserSystemDirectory(UserHandle.USER_SYSTEM), 81 "wallpaper-tmp").getAbsolutePath(); 82 83 Context mContext; 84 String[] mFiles; 85 String[] mKeys; 86 double mDesiredMinWidth; 87 double mDesiredMinHeight; 88 89 /** 90 * Construct a helper for backing up / restoring the files at the given absolute locations 91 * within the file system. 92 * 93 * @param context 94 * @param files 95 */ 96 public WallpaperBackupHelper(Context context, String[] files, String[] keys) { 97 super(context); 98 99 mContext = context; 100 mFiles = files; 101 mKeys = keys; 102 103 final WindowManager wm = 104 (WindowManager) context.getSystemService(Context.WINDOW_SERVICE); 105 final WallpaperManager wpm = 106 (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE); 107 final Display d = wm.getDefaultDisplay(); 108 final Point size = new Point(); 109 d.getSize(size); 110 mDesiredMinWidth = Math.min(size.x, size.y); 111 mDesiredMinHeight = (double) wpm.getDesiredMinimumHeight(); 112 if (mDesiredMinHeight <= 0) { 113 mDesiredMinHeight = size.y; 114 } 115 116 if (DEBUG) { 117 Slog.d(TAG, "dmW=" + mDesiredMinWidth + " dmH=" + mDesiredMinHeight); 118 } 119 } 120 121 /** 122 * Based on oldState, determine which of the files from the application's data directory 123 * need to be backed up, write them to the data stream, and fill in newState with the 124 * state as it exists now. 125 */ 126 @Override 127 public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 128 ParcelFileDescriptor newState) { 129 performBackup_checked(oldState, data, newState, mFiles, mKeys); 130 } 131 132 /** 133 * Restore one absolute file entity from the restore stream. If we're restoring the 134 * magic wallpaper file, take specific action to determine whether it is suitable for 135 * the current device. 136 */ 137 @Override 138 public void restoreEntity(BackupDataInputStream data) { 139 final String key = data.getKey(); 140 if (isKeyInList(key, mKeys)) { 141 if (key.equals(WALLPAPER_IMAGE_KEY)) { 142 // restore the file to the stage for inspection 143 File f = new File(STAGE_FILE); 144 if (writeFile(f, data)) { 145 146 // Preflight the restored image's dimensions without loading it 147 BitmapFactory.Options options = new BitmapFactory.Options(); 148 options.inJustDecodeBounds = true; 149 BitmapFactory.decodeFile(STAGE_FILE, options); 150 151 if (DEBUG) Slog.d(TAG, "Restoring wallpaper image w=" + options.outWidth 152 + " h=" + options.outHeight); 153 154 if (REJECT_OUTSIZED_RESTORE) { 155 // We accept any wallpaper that is at least as wide as our preference 156 // (i.e. wide enough to fill the screen), and is within a comfortable 157 // factor of the target height, to avoid significant clipping/scaling/ 158 // letterboxing. At this point we know that mDesiredMinWidth is the 159 // smallest dimension, regardless of current orientation, so we can 160 // safely require that the candidate's width and height both exceed 161 // that hard minimum. 162 final double heightRatio = mDesiredMinHeight / options.outHeight; 163 if (options.outWidth < mDesiredMinWidth 164 || options.outHeight < mDesiredMinWidth 165 || heightRatio >= MAX_HEIGHT_RATIO 166 || heightRatio <= MIN_HEIGHT_RATIO) { 167 // Not wide enough for the screen, or too short/tall to be a good fit 168 // for the height of the screen, broken image file, or the system's 169 // desires for wallpaper size are in a bad state. Probably one of the 170 // first two. 171 Slog.i(TAG, "Restored image dimensions (w=" 172 + options.outWidth + ", h=" + options.outHeight 173 + ") too far off target (tw=" 174 + mDesiredMinWidth + ", th=" + mDesiredMinHeight 175 + "); falling back to default wallpaper."); 176 f.delete(); 177 return; 178 } 179 } 180 181 // We passed the acceptable-dimensions test (if any), so we're going to 182 // use the restored image. That comes last, when we are done restoring 183 // both the pixels and the metadata. 184 } 185 } else if (key.equals(WALLPAPER_INFO_KEY)) { 186 // XML file containing wallpaper info 187 File f = new File(WALLPAPER_INFO); 188 writeFile(f, data); 189 } 190 } 191 } 192 193 /** 194 * Hook for the agent to call this helper upon completion of the restore. We do this 195 * upon completion so that we know both the imagery and the wallpaper info have 196 * been emplaced without requiring either or relying on ordering. 197 */ 198 public void onRestoreFinished() { 199 final File f = new File(STAGE_FILE); 200 if (f.exists()) { 201 // TODO: spin a service to copy the restored image to sd/usb storage, 202 // since it does not exist anywhere other than the private wallpaper 203 // file. 204 Slog.d(TAG, "Applying restored wallpaper image."); 205 f.renameTo(new File(WALLPAPER_ORIG_IMAGE)); 206 } 207 } 208 } 209
