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      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     // This path must match what the WallpaperManagerService uses
     43     // TODO: Will need to change if backing up non-primary user's wallpaper
     44     public static final String WALLPAPER_IMAGE =
     45             new File(Environment.getUserSystemDirectory(UserHandle.USER_OWNER),
     46                     "wallpaper").getAbsolutePath();
     47     public static final String WALLPAPER_INFO =
     48             new File(Environment.getUserSystemDirectory(UserHandle.USER_OWNER),
     49                     "wallpaper_info.xml").getAbsolutePath();
     50     // Use old keys to keep legacy data compatibility and avoid writing two wallpapers
     51     public static final String WALLPAPER_IMAGE_KEY =
     52             "/data/data/com.android.settings/files/wallpaper";
     53     public static final String WALLPAPER_INFO_KEY = "/data/system/wallpaper_info.xml";
     54 
     55     // Stage file - should be adjacent to the WALLPAPER_IMAGE location.  The wallpapers
     56     // will be saved to this file from the restore stream, then renamed to the proper
     57     // location if it's deemed suitable.
     58     // TODO: Will need to change if backing up non-primary user's wallpaper
     59     private static final String STAGE_FILE =
     60             new File(Environment.getUserSystemDirectory(UserHandle.USER_OWNER),
     61                     "wallpaper-tmp").getAbsolutePath();
     62 
     63     Context mContext;
     64     String[] mFiles;
     65     String[] mKeys;
     66     double mDesiredMinWidth;
     67     double mDesiredMinHeight;
     68 
     69     /**
     70      * Construct a helper for backing up / restoring the files at the given absolute locations
     71      * within the file system.
     72      *
     73      * @param context
     74      * @param files
     75      */
     76     public WallpaperBackupHelper(Context context, String[] files, String[] keys) {
     77         super(context);
     78 
     79         mContext = context;
     80         mFiles = files;
     81         mKeys = keys;
     82 
     83         WallpaperManager wpm;
     84         wpm = (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE);
     85         mDesiredMinWidth = (double) wpm.getDesiredMinimumWidth();
     86         mDesiredMinHeight = (double) wpm.getDesiredMinimumHeight();
     87 
     88         if (mDesiredMinWidth <= 0 || mDesiredMinHeight <= 0) {
     89             WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
     90             Display d = wm.getDefaultDisplay();
     91             Point size = new Point();
     92             d.getSize(size);
     93             mDesiredMinWidth = size.x;
     94             mDesiredMinHeight = size.y;
     95         }
     96 
     97         if (DEBUG) {
     98             Slog.d(TAG, "dmW=" + mDesiredMinWidth + " dmH=" + mDesiredMinHeight);
     99         }
    100     }
    101 
    102     /**
    103      * Based on oldState, determine which of the files from the application's data directory
    104      * need to be backed up, write them to the data stream, and fill in newState with the
    105      * state as it exists now.
    106      */
    107     public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
    108             ParcelFileDescriptor newState) {
    109         performBackup_checked(oldState, data, newState, mFiles, mKeys);
    110     }
    111 
    112     /**
    113      * Restore one absolute file entity from the restore stream.  If we're restoring the
    114      * magic wallpaper file, take specific action to determine whether it is suitable for
    115      * the current device.
    116      */
    117     public void restoreEntity(BackupDataInputStream data) {
    118         final String key = data.getKey();
    119         if (isKeyInList(key, mKeys)) {
    120             if (key.equals(WALLPAPER_IMAGE_KEY)) {
    121                 // restore the file to the stage for inspection
    122                 File f = new File(STAGE_FILE);
    123                 if (writeFile(f, data)) {
    124 
    125                     // Preflight the restored image's dimensions without loading it
    126                     BitmapFactory.Options options = new BitmapFactory.Options();
    127                     options.inJustDecodeBounds = true;
    128                     BitmapFactory.decodeFile(STAGE_FILE, options);
    129 
    130                     if (DEBUG) Slog.d(TAG, "Restoring wallpaper image w=" + options.outWidth
    131                             + " h=" + options.outHeight);
    132 
    133                     // How much does the image differ from our preference?  The threshold
    134                     // here is set to accept any image larger than our target, because
    135                     // scaling down is acceptable; but to reject images that are deemed
    136                     // "too small" to scale up attractively.  The value 1.33 is just barely
    137                     // too low to pass Nexus 1 or Droid wallpapers for use on a Xoom, but
    138                     // will pass anything relatively larger.
    139                     double widthRatio = mDesiredMinWidth / options.outWidth;
    140                     double heightRatio = mDesiredMinHeight / options.outHeight;
    141                     if (widthRatio > 0 && widthRatio < 1.33
    142                             && heightRatio > 0 && heightRatio < 1.33) {
    143                         // sufficiently close to our resolution; go ahead and use it
    144                         if (DEBUG) Slog.d(TAG, "wallpaper dimension match; using");
    145                         f.renameTo(new File(WALLPAPER_IMAGE));
    146                         // TODO: spin a service to copy the restored image to sd/usb storage,
    147                         // since it does not exist anywhere other than the private wallpaper
    148                         // file.
    149                     } else {
    150                         if (DEBUG) Slog.d(TAG, "dimensions too far off: wr=" + widthRatio
    151                                 + " hr=" + heightRatio);
    152                         f.delete();
    153                     }
    154                 }
    155             } else if (key.equals(WALLPAPER_INFO_KEY)) {
    156                 // XML file containing wallpaper info
    157                 File f = new File(WALLPAPER_INFO);
    158                 writeFile(f, data);
    159             }
    160         }
    161     }
    162 }
    163