/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.lang.reflect.InvocationHandler;
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import java.lang.reflect.Method;
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import java.lang.reflect.Proxy;
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interface TestInterface {
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void method0();
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void method1(String arg);
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void method10(String arg1, String arg2, String arg3, String arg4, String arg5,
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String arg6, String arg7, String arg8, String arg9, String arg10);
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void method10Even(byte arg1, String arg2, short arg3, String arg4, int arg5,
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String arg6, long arg7, String arg8, double arg9, String arg10);
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}
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class TestInvocationHandler implements InvocationHandler {
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@Override
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public Object invoke(Object proxy, Method method, Object[] args) {
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// Force garbage collection to try to make `proxy` move in memory
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// (in the case of a moving garbage collector).
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System.gc();
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System.out.println("Proxy for " + TestInterface.class + "." + method.getName());
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if (method.getName().equals("method0")) {
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testMethod0(proxy, args);
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} else if (method.getName().equals("method1")) {
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testMethod1(proxy, args);
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} else if (method.getName().equals("method10")) {
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testMethod10(proxy, args);
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} else if (method.getName().equals("method10Even")) {
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testMethod10Even(proxy, args);
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}
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return null;
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}
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private void testMethod0(Object proxy, Object[] args) {
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// Get argument 0 (method target) from the proxy method frame ($Proxy0.method0 activation).
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Object arg0 = getProxyMethodArgument(0);
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System.out.println(" arg0: " + arg0.getClass().getName());
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Main.assertEquals(proxy, arg0);
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}
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private void testMethod1(Object proxy, Object[] args) {
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// Get argument 0 (method target) from the proxy method frame ($Proxy0.method0 activation).
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Object arg0 = getProxyMethodArgument(0);
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System.out.println(" arg0: " + arg0.getClass().getName());
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Main.assertEquals(proxy, arg0);
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// Get argument 1 from the proxy method frame ($Proxy0.method1 activation).
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String arg1 = (String) getProxyMethodArgument(1);
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System.out.println(" arg1: " + arg1.getClass().getName() + " \"" + arg1 + "\"");
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Main.assertEquals(args[0], arg1);
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}
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private void testMethod10(Object proxy, Object[] args) {
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// Get argument 0 (method target) from the proxy method frame ($Proxy0.method10 activation).
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Object arg0 = getProxyMethodArgument(0);
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System.out.println(" arg0: " + arg0.getClass().getName());
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Main.assertEquals(proxy, arg0);
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// Get argument `i` from the proxy method frame ($Proxy0.method10 activation).
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for (int i = 0; i < 10; ++i) {
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int arg_pos = i + 1;
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String arg = (String) getProxyMethodArgument(arg_pos);
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System.out.println(" arg" + arg_pos + ": " + arg.getClass().getName() + " \"" + arg + "\"");
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Main.assertEquals(args[i], arg);
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}
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}
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private void testMethod10Even(Object proxy, Object[] args) {
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// Get argument 0 (method target) from the proxy method frame ($Proxy0.method10Even
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// activation).
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Object arg0 = getProxyMethodArgument(0);
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System.out.println(" arg0: " + arg0.getClass().getName());
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Main.assertEquals(proxy, arg0);
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// Get argument `i` from the proxy method frame ($Proxy0.method10Even activation).
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for (int i = 1; i < 10; i += 2) {
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int arg_pos = i + 1;
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String arg = (String) getProxyMethodArgument(arg_pos);
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System.out.println(" arg" + arg_pos + ": " + arg.getClass().getName() + " \"" + arg + "\"");
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Main.assertEquals(args[i], arg);
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}
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}
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// Get reference argument at position `arg_pos` in proxy frame.
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// This method should only be called from one of the
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// `TestInvocationHandler.testMethod*` methods via `TestInvocationHandler.invoke`.
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private Object getProxyMethodArgument(int arg_pos) {
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// Find proxy frame in stack (from a testMethod* method).
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//
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// depth method
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// ----------------------------------------------------------------------
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// 0 TestInvocationHandler.getArgument (outermost frame)
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// 1 TestInvocationHandler.getProxyMethodArgument
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// 2 TestInvocationHandler.testMethod*
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// 3 TestInvocationHandler.invoke
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// 4 java.lang.reflect.Proxy.invoke
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// -> 5 TestInterface.method* (proxy method)
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// 6 Main.main (innermost frame)
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//
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int proxy_method_frame_depth = 5;
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return getArgument(arg_pos, proxy_method_frame_depth);
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}
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// Get reference argument at position `arg_pos` in frame at depth `frame_depth`.
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private native Object getArgument(int arg_pos, int frame_depth);
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}
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public class Main {
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public static void main(String[] args) {
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System.loadLibrary(args[0]);
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TestInvocationHandler invocationHandler = new TestInvocationHandler();
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TestInterface proxy = (TestInterface) Proxy.newProxyInstance(
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Main.class.getClassLoader(),
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new Class<?>[] { TestInterface.class },
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invocationHandler);
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System.out.println("proxy: " + proxy.getClass().getName());
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proxy.method0();
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proxy.method1("a");
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proxy.method10("one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten");
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proxy.method10Even((byte) 1, "two", (short) 3, "four", 5, "six", 7L, "eight", 9.0, "ten");
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}
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public static void assertEquals(Object expected, Object actual) {
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if (expected != actual) {
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throw new Error("Expected " + expected + ", got " + actual);
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}
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}
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public static void assertEquals(String expected, String actual) {
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if (expected != actual) {
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throw new Error("Expected \"" + expected + "\", got \"" + actual + "\"");
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}
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}
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}
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