1 /*
2  * Copyright (C) 2017 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 art;
18 
19 import java.lang.reflect.Method;
20 import java.util.HashMap;
21 
22 public class Test986 {
23   private static final HashMap<Method, String> SymbolMap = new HashMap<>();
24 
25   // A class with a native method we can play with.
26   static class Transform {
sayHi()27     private static native void sayHi();
sayHi2()28     private static native void sayHi2();
29   }
30 
run()31   public static void run() throws Exception {
32     setupNativeBindNotify();
33     setNativeBindNotify(true);
34     doTest();
35   }
36 
setNativeTransform(Method method, String dest)37   private static void setNativeTransform(Method method, String dest) {
38     SymbolMap.put(method, dest);
39   }
40 
removeNativeTransform(Method method)41   private static void removeNativeTransform(Method method) {
42     SymbolMap.remove(method);
43   }
44 
45   /**
46    * Notifies java that a native method bind has occurred and requests the new symbol to bind to.
47    */
doNativeMethodBind(Method method, String nativeSym)48   public static String doNativeMethodBind(Method method, String nativeSym) {
49     // Disable native bind notify for now to avoid infinite loops.
50     setNativeBindNotify(false);
51     String transSym = SymbolMap.getOrDefault(method, nativeSym);
52     System.out.println(method + " = " + nativeSym + " -> " + transSym);
53     setNativeBindNotify(true);
54     return transSym;
55   }
56 
doTest()57   public static void doTest() throws Exception {
58     Method say_hi_method = Transform.class.getDeclaredMethod("sayHi");
59 
60     // Test we will bind fine if we make no changes.
61     Transform.sayHi2();
62 
63     // Test we can get in the middle of autobind
64     setNativeTransform(say_hi_method, "NoReallySayGoodbye");
65     Transform.sayHi();
66 
67     // Test we can get in between manual bind.
68     setNativeTransform(say_hi_method, "Java_art_Test986_00024Transform_sayHi2");
69     rebindTransformClass();
70     Transform.sayHi();
71 
72     // Test we can get rid of transform
73     removeNativeTransform(say_hi_method);
74     rebindTransformClass();
75     Transform.sayHi();
76   }
77 
78   // Functions called from native code.
doSayHi()79   public static void doSayHi() {
80     System.out.println("Hello");
81   }
82 
doSayHi2()83   public static void doSayHi2() {
84     System.out.println("Hello - 2");
85   }
86 
doSayBye()87   public static void doSayBye() {
88     System.out.println("Bye");
89   }
90 
setNativeBindNotify(boolean enable)91   private static native void setNativeBindNotify(boolean enable);
setupNativeBindNotify()92   private static native void setupNativeBindNotify();
rebindTransformClass()93   private static void rebindTransformClass() {
94     rebindTransformClass(Transform.class);
95   }
rebindTransformClass(Class<?> trans)96   private static native void rebindTransformClass(Class<?> trans);
97 }
98