1 /*
2  * Copyright (C) 2019 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 dalvik.system.PathClassLoader;
18 import dalvik.system.VMRuntime;
19 
20 import java.lang.ref.WeakReference;
21 import java.lang.reflect.Constructor;
22 import java.util.concurrent.atomic.AtomicBoolean;
23 
24 public class Main {
25     static final String DEX_FILE = System.getenv("DEX_LOCATION") + "/1002-notify-startup.jar";
26     static final String LIBRARY_SEARCH_PATH = System.getProperty("java.library.path");
27     static AtomicBoolean completed = new AtomicBoolean(false);
28 
main(String[] args)29     public static void main(String[] args) {
30         System.loadLibrary(args[0]);
31         System.out.println("Startup completed: " + hasStartupCompleted());
32         Thread workerThread = new WorkerThread();
33         workerThread.start();
34         do {
35             resetStartupCompleted();
36             VMRuntime.getRuntime().notifyStartupCompleted();
37             Thread.yield();
38         } while (!completed.get());
39         try {
40             workerThread.join();
41         } catch (Throwable e) {
42             System.err.println(e);
43         }
44         System.out.println("Startup completed: " + hasStartupCompleted());
45     }
46 
47     private static class WorkerThread extends Thread {
48         static final int NUM_ITERATIONS = 100;
49 
$noinline$loadClassInLoader()50         private WeakReference<Class<?>> $noinline$loadClassInLoader() throws Exception {
51             ClassLoader loader = new PathClassLoader(
52                     DEX_FILE, LIBRARY_SEARCH_PATH, ClassLoader.getSystemClassLoader());
53             Class ret = loader.loadClass("Main");
54             return new WeakReference(ret);
55         }
56 
run()57         public void run() {
58             for (int i = 0; i < NUM_ITERATIONS; ++i) {
59                 try {
60                     WeakReference<Class<?>> ref = $noinline$loadClassInLoader();
61                     Runtime.getRuntime().gc();
62                     Thread.yield();
63                     // Don't validate the unloading since app images will keep classes live (for now).
64                 } catch (Throwable e) {
65                     System.err.println(e);
66                     break;
67                 }
68             }
69             completed.set(true);
70         }
71     }
72 
hasStartupCompleted()73     private static native boolean hasStartupCompleted();
resetStartupCompleted()74     private static native void resetStartupCompleted();
75 }
76