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      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 
     17 import java.util.Arrays;
     18 import java.util.HashSet;
     19 import java.util.Set;
     20 
     21 /**
     22  * Policy that governs which classes are preloaded.
     23  */
     24 public class Policy {
     25 
     26     /**
     27      * No constructor - use static methods only
     28      */
     29     private Policy() {}
     30 
     31     /**
     32      * This location (in the build system) of the preloaded-classes file.
     33      */
     34     static final String PRELOADED_CLASS_FILE
     35             = "frameworks/base/preloaded-classes";
     36 
     37     /**
     38      * Long running services. These are restricted in their contribution to the
     39      * preloader because their launch time is less critical.
     40      */
     41     // TODO: Generate this automatically from package manager.
     42     private static final Set<String> SERVICES = new HashSet<String>(Arrays.asList(
     43         "system_server",
     44         "com.google.process.content",
     45         "android.process.media",
     46         "com.android.bluetooth",
     47         "com.android.calendar",
     48         "com.android.inputmethod.latin",
     49         "com.android.phone",
     50         "com.google.android.apps.maps.FriendService", // pre froyo
     51         "com.google.android.apps.maps:FriendService", // froyo
     52         "com.google.android.apps.maps.LocationFriendService",
     53         "com.google.android.deskclock",
     54         "com.google.process.gapps",
     55         "android.tts"
     56     ));
     57 
     58     /**
     59      * Classes which we shouldn't load from the Zygote.
     60      */
     61     private static final Set<String> EXCLUDED_CLASSES
     62             = new HashSet<String>(Arrays.asList(
     63         // Binders
     64         "android.app.AlarmManager",
     65         "android.app.SearchManager",
     66         "android.os.FileObserver",
     67         "com.android.server.PackageManagerService$AppDirObserver",
     68 
     69         // Threads
     70         "android.os.AsyncTask",
     71         "android.pim.ContactsAsyncHelper",
     72         "android.webkit.WebViewClassic$1",
     73         "java.lang.ProcessManager"
     74     ));
     75 
     76     /**
     77      * Returns true if the given process name is a "long running" process or
     78      * service.
     79      */
     80     public static boolean isService(String processName) {
     81         return SERVICES.contains(processName);
     82     }
     83 
     84     /** Reports if the given class should be preloaded. */
     85     public static boolean isPreloadable(LoadedClass clazz) {
     86         return clazz.systemClass && !EXCLUDED_CLASSES.contains(clazz.name)
     87                 && !clazz.name.endsWith("$NoPreloadHolder");
     88     }
     89 }
     90