1/* 2 * Copyright (C) 2008 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 com.android.server; 18 19import static android.os.FileObserver.*; 20import static android.os.ParcelFileDescriptor.*; 21 22import android.app.IWallpaperService; 23import android.app.IWallpaperServiceCallback; 24import android.backup.BackupManager; 25import android.content.Context; 26import android.content.Intent; 27import android.content.SharedPreferences; 28import android.content.pm.PackageManager; 29import android.os.Binder; 30import android.os.RemoteException; 31import android.os.FileObserver; 32import android.os.ParcelFileDescriptor; 33import android.os.RemoteCallbackList; 34import android.util.Config; 35import android.util.Log; 36 37import java.io.File; 38import java.io.FileNotFoundException; 39 40class WallpaperService extends IWallpaperService.Stub { 41 private static final String TAG = WallpaperService.class.getSimpleName(); 42 43 private static final File WALLPAPER_DIR = new File( 44 "/data/data/com.android.settings/files"); 45 private static final String WALLPAPER = "wallpaper"; 46 private static final File WALLPAPER_FILE = new File(WALLPAPER_DIR, WALLPAPER); 47 48 private static final String PREFERENCES = "wallpaper-hints"; 49 50 private static final String HINT_WIDTH = "hintWidth"; 51 private static final String HINT_HEIGHT = "hintHeight"; 52 53 /** 54 * List of callbacks registered they should each be notified 55 * when the wallpaper is changed. 56 */ 57 private final RemoteCallbackList<IWallpaperServiceCallback> mCallbacks 58 = new RemoteCallbackList<IWallpaperServiceCallback>(); 59 60 /** 61 * Observes the wallpaper for changes and notifies all IWallpaperServiceCallbacks 62 * that the wallpaper has changed. The CREATE is triggered when there is no 63 * wallpaper set and is created for the first time. The CLOSE_WRITE is triggered 64 * everytime the wallpaper is changed. 65 */ 66 private final FileObserver mWallpaperObserver = new FileObserver( 67 WALLPAPER_DIR.getAbsolutePath(), CREATE | CLOSE_WRITE) { 68 @Override 69 public void onEvent(int event, String path) { 70 if (path == null) { 71 return; 72 } 73 74 File changedFile = new File(WALLPAPER_DIR, path); 75 if (WALLPAPER_FILE.equals(changedFile)) { 76 notifyCallbacks(); 77 } 78 } 79 }; 80 81 private final Context mContext; 82 83 private int mWidth = -1; 84 private int mHeight = -1; 85 86 public WallpaperService(Context context) { 87 if (Config.LOGD) Log.d(TAG, "WallpaperService startup"); 88 mContext = context; 89 createFilesDir(); 90 mWallpaperObserver.startWatching(); 91 92 SharedPreferences preferences = mContext.getSharedPreferences(PREFERENCES, 93 Context.MODE_PRIVATE); 94 mWidth = preferences.getInt(HINT_WIDTH, -1); 95 mHeight = preferences.getInt(HINT_HEIGHT, -1); 96 } 97 98 @Override 99 protected void finalize() throws Throwable { 100 super.finalize(); 101 mWallpaperObserver.stopWatching(); 102 } 103 104 public void clearWallpaper() { 105 File f = WALLPAPER_FILE; 106 if (f.exists()) { 107 f.delete(); 108 } 109 } 110 111 public void setDimensionHints(int width, int height) throws RemoteException { 112 checkPermission(android.Manifest.permission.SET_WALLPAPER_HINTS); 113 114 if (width <= 0 || height <= 0) { 115 throw new IllegalArgumentException("width and height must be > 0"); 116 } 117 118 if (width != mWidth || height != mHeight) { 119 mWidth = width; 120 mHeight = height; 121 122 SharedPreferences preferences = mContext.getSharedPreferences(PREFERENCES, 123 Context.MODE_PRIVATE); 124 125 final SharedPreferences.Editor editor = preferences.edit(); 126 editor.putInt(HINT_WIDTH, width); 127 editor.putInt(HINT_HEIGHT, height); 128 editor.commit(); 129 } 130 } 131 132 public int getWidthHint() throws RemoteException { 133 return mWidth; 134 } 135 136 public int getHeightHint() throws RemoteException { 137 return mHeight; 138 } 139 140 public ParcelFileDescriptor getWallpaper(IWallpaperServiceCallback cb) { 141 try { 142 mCallbacks.register(cb); 143 File f = WALLPAPER_FILE; 144 if (!f.exists()) { 145 return null; 146 } 147 return ParcelFileDescriptor.open(f, MODE_READ_ONLY); 148 } catch (FileNotFoundException e) { 149 150 /* Shouldn't happen as we check to see if the file exists */ 151 if (Config.LOGD) Log.d(TAG, "Error getting wallpaper", e); 152 } 153 return null; 154 } 155 156 public ParcelFileDescriptor setWallpaper() { 157 checkPermission(android.Manifest.permission.SET_WALLPAPER); 158 try { 159 ParcelFileDescriptor fd = ParcelFileDescriptor.open(WALLPAPER_FILE, 160 MODE_CREATE|MODE_READ_WRITE); 161 162 // changing the wallpaper means we'll need to back up the new one 163 long origId = Binder.clearCallingIdentity(); 164 BackupManager bm = new BackupManager(mContext); 165 bm.dataChanged(); 166 Binder.restoreCallingIdentity(origId); 167 168 return fd; 169 } catch (FileNotFoundException e) { 170 if (Config.LOGD) Log.d(TAG, "Error setting wallpaper", e); 171 } 172 return null; 173 } 174 175 private void createFilesDir() { 176 if (!WALLPAPER_DIR.exists()) { 177 WALLPAPER_DIR.mkdirs(); 178 } 179 } 180 181 private void notifyCallbacks() { 182 final int n = mCallbacks.beginBroadcast(); 183 for (int i = 0; i < n; i++) { 184 try { 185 mCallbacks.getBroadcastItem(i).onWallpaperChanged(); 186 } catch (RemoteException e) { 187 188 // The RemoteCallbackList will take care of removing 189 // the dead object for us. 190 } 191 } 192 mCallbacks.finishBroadcast(); 193 final Intent intent = new Intent(Intent.ACTION_WALLPAPER_CHANGED); 194 mContext.sendBroadcast(intent); 195 } 196 197 private void checkPermission(String permission) { 198 if (PackageManager.PERMISSION_GRANTED != mContext.checkCallingOrSelfPermission(permission)) { 199 throw new SecurityException("Access denied to process: " + Binder.getCallingPid() 200 + ", must have permission " + permission); 201 } 202 } 203} 204