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
17package android.app.backup;
18
19import android.app.WallpaperManager;
20import android.content.Context;
21import android.graphics.BitmapFactory;
22import android.graphics.Point;
23import android.os.Environment;
24import android.os.ParcelFileDescriptor;
25import android.os.UserHandle;
26import android.util.Slog;
27import android.view.Display;
28import android.view.WindowManager;
29
30import 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 */
38public 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