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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.ParcelFileDescriptor;
     24 import android.util.Slog;
     25 import android.view.Display;
     26 import android.view.WindowManager;
     27 
     28 import java.io.File;
     29 
     30 /**
     31  * Helper for backing up / restoring wallpapers.  Basically an AbsoluteFileBackupHelper,
     32  * but with logic for deciding what to do with restored wallpaper images.
     33  *
     34  * @hide
     35  */
     36 public class WallpaperBackupHelper extends FileBackupHelperBase implements BackupHelper {
     37     private static final String TAG = "WallpaperBackupHelper";
     38     private static final boolean DEBUG = false;
     39 
     40     // This path must match what the WallpaperManagerService uses
     41     private static final String WALLPAPER_IMAGE = "/data/data/com.android.settings/files/wallpaper";
     42 
     43     // Stage file - should be adjacent to the WALLPAPER_IMAGE location.  The wallpapers
     44     // will be saved to this file from the restore stream, then renamed to the proper
     45     // location if it's deemed suitable.
     46     private static final String STAGE_FILE = "/data/data/com.android.settings/files/wallpaper-tmp";
     47 
     48     Context mContext;
     49     String[] mFiles;
     50     double mDesiredMinWidth;
     51     double mDesiredMinHeight;
     52 
     53     /**
     54      * Construct a helper for backing up / restoring the files at the given absolute locations
     55      * within the file system.
     56      *
     57      * @param context
     58      * @param files
     59      */
     60     public WallpaperBackupHelper(Context context, String... files) {
     61         super(context);
     62 
     63         mContext = context;
     64         mFiles = files;
     65 
     66         WallpaperManager wpm;
     67         wpm = (WallpaperManager) context.getSystemService(Context.WALLPAPER_SERVICE);
     68         mDesiredMinWidth = (double) wpm.getDesiredMinimumWidth();
     69         mDesiredMinHeight = (double) wpm.getDesiredMinimumHeight();
     70 
     71         if (mDesiredMinWidth <= 0 || mDesiredMinHeight <= 0) {
     72             WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
     73             Display d = wm.getDefaultDisplay();
     74             Point size = new Point();
     75             d.getSize(size);
     76             mDesiredMinWidth = size.x;
     77             mDesiredMinHeight = size.y;
     78         }
     79 
     80         if (DEBUG) {
     81             Slog.d(TAG, "dmW=" + mDesiredMinWidth + " dmH=" + mDesiredMinHeight);
     82         }
     83     }
     84 
     85     /**
     86      * Based on oldState, determine which of the files from the application's data directory
     87      * need to be backed up, write them to the data stream, and fill in newState with the
     88      * state as it exists now.
     89      */
     90     public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
     91             ParcelFileDescriptor newState) {
     92         performBackup_checked(oldState, data, newState, mFiles, mFiles);
     93     }
     94 
     95     /**
     96      * Restore one absolute file entity from the restore stream.  If we're restoring the
     97      * magic wallpaper file, take specific action to determine whether it is suitable for
     98      * the current device.
     99      */
    100     public void restoreEntity(BackupDataInputStream data) {
    101         final String key = data.getKey();
    102         if (isKeyInList(key, mFiles)) {
    103             if (key.equals(WALLPAPER_IMAGE)) {
    104                 // restore the file to the stage for inspection
    105                 File f = new File(STAGE_FILE);
    106                 if (writeFile(f, data)) {
    107 
    108                     // Preflight the restored image's dimensions without loading it
    109                     BitmapFactory.Options options = new BitmapFactory.Options();
    110                     options.inJustDecodeBounds = true;
    111                     BitmapFactory.decodeFile(STAGE_FILE, options);
    112 
    113                     if (DEBUG) Slog.d(TAG, "Restoring wallpaper image w=" + options.outWidth
    114                             + " h=" + options.outHeight);
    115 
    116                     // How much does the image differ from our preference?  The threshold
    117                     // here is set to accept any image larger than our target, because
    118                     // scaling down is acceptable; but to reject images that are deemed
    119                     // "too small" to scale up attractively.  The value 1.33 is just barely
    120                     // too low to pass Nexus 1 or Droid wallpapers for use on a Xoom, but
    121                     // will pass anything relatively larger.
    122                     double widthRatio = mDesiredMinWidth / options.outWidth;
    123                     double heightRatio = mDesiredMinHeight / options.outHeight;
    124                     if (widthRatio > 0 && widthRatio < 1.33
    125                             && heightRatio > 0 && heightRatio < 1.33) {
    126                         // sufficiently close to our resolution; go ahead and use it
    127                         if (DEBUG) Slog.d(TAG, "wallpaper dimension match; using");
    128                         f.renameTo(new File(WALLPAPER_IMAGE));
    129                         // TODO: spin a service to copy the restored image to sd/usb storage,
    130                         // since it does not exist anywhere other than the private wallpaper
    131                         // file.
    132                     } else {
    133                         if (DEBUG) Slog.d(TAG, "dimensions too far off: wr=" + widthRatio
    134                                 + " hr=" + heightRatio);
    135                         f.delete();
    136                     }
    137                 }
    138             } else {
    139                 // Some other normal file; just decode it to its destination
    140                 File f = new File(key);
    141                 writeFile(f, data);
    142             }
    143         }
    144     }
    145 }
    146