com.google.dexmaker.ProxyBuilder.java Source code

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/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.dexmaker;

import static java.lang.reflect.Modifier.PRIVATE;
import static java.lang.reflect.Modifier.PUBLIC;
import static java.lang.reflect.Modifier.STATIC;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.UndeclaredThrowableException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

import android.app.Application;
import android.content.Context;

/**
 * Creates dynamic proxies of concrete classes.
 * <p>
 * This is similar to the {@code java.lang.reflect.Proxy} class, but works for classes instead of interfaces.
 * <h3>Example</h3>
 * The following example demonstrates the creation of a dynamic proxy for {@code java.util.Random} which will always return 4 when asked for integers, and which logs method calls to every method.
 * 
 * <pre>
 * InvocationHandler handler = new InvocationHandler() {
 *    &#064;Override
 *    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 *       if (method.getName().equals(&quot;nextInt&quot;)) {
 *          // Chosen by fair dice roll, guaranteed to be random.
 *          return 4;
 *       }
 *       Object result = ProxyBuilder.callSuper(proxy, method, args);
 *       System.out.println(&quot;Method: &quot; + method.getName() + &quot; args: &quot; + Arrays.toString(args) + &quot; result: &quot; + result);
 *       return result;
 *    }
 * };
 * Random debugRandom = ProxyBuilder.forClass(Random.class).dexCache(getInstrumentation().getTargetContext().getDir(&quot;dx&quot;, Context.MODE_PRIVATE)).handler(handler).build();
 * assertEquals(4, debugRandom.nextInt());
 * debugRandom.setSeed(0);
 * assertTrue(debugRandom.nextBoolean());
 * </pre>
 * 
 * <h3>Usage</h3>
 * Call {@link #forClass(Class)} for the Class you wish to proxy. Call {@link #handler(InvocationHandler)} passing in an {@link InvocationHandler}, and then call {@link #build()}. The returned instance will be a dynamically generated subclass where all method calls will be delegated to the invocation handler, except as noted below.
 * <p>
 * The static method {@link #callSuper(Object, Method, Object...)} allows you to access the original super method for a given proxy. This allows the invocation handler to selectively override some methods but not others.
 * <p>
 * By default, the {@link #build()} method will call the no-arg constructor belonging to the class being proxied. If you wish to call a different constructor, you must provide arguments for both {@link #constructorArgTypes(Class[])} and {@link #constructorArgValues(Object[])}.
 * <p>
 * This process works only for classes with public and protected level of visibility.
 * <p>
 * You may proxy abstract classes. You may not proxy final classes.
 * <p>
 * Only non-private, non-final, non-static methods will be dispatched to the invocation handler. Private, static or final methods will always call through to the superclass as normal.
 * <p>
 * The {@link #finalize()} method on {@code Object} will not be proxied.
 * <p>
 * You must provide a dex cache directory via the {@link #dexCache(File)} method. You should take care not to make this a world-writable directory, so that third parties cannot inject code into your application. A suitable parameter for these output directories would be something like this:
 * 
 * <pre>
 * {@code
 *     getApplicationContext().getDir("dx", Context.MODE_PRIVATE);
 * }
 * </pre>
 * <p>
 * If the base class to be proxied leaks the {@code this} pointer in the constructor (bad practice), that is to say calls a non-private non-final method from the constructor, the invocation handler will not be invoked. As a simple concrete example, when proxying Random we discover that it inernally calls setSeed during the constructor. The proxy will not intercept this call during proxy construction, but will intercept as normal afterwards. This behaviour may be subject to change in future releases.
 * <p>
 * This class is <b>not thread safe</b>.
 */
public final class ProxyBuilder<T> {
    private static final String FIELD_NAME_HANDLER = "$__handler";
    private static final String FIELD_NAME_METHODS = "$__methodArray";

    /**
     * A cache of all proxy classes ever generated. At the time of writing, Android's runtime doesn't support class unloading so there's little value in using weak references.
     */
    private static final Map<Class<?>, Class<?>> generatedProxyClasses = Collections
            .synchronizedMap(new HashMap<Class<?>, Class<?>>());

    private static final Map<String, ArrayList<MethodEntity>> proxy = new HashMap<String, ArrayList<MethodEntity>>();

    private final Class<T> baseClass;
    private ClassLoader parentClassLoader = ProxyBuilder.class.getClassLoader();
    private InvocationHandler handler;
    private File dexCache;
    private Class<?>[] constructorArgTypes = new Class[0];
    private Object[] constructorArgValues = new Object[0];
    private Set<Class<?>> interfaces = new HashSet<Class<?>>();
    private ArrayList<MethodEntity> methods = new ArrayList<MethodEntity>();
    private Application application;
    private static Class fragment;
    private static Class fragmentV4;

    private ProxyBuilder(Class<T> clazz) {
        baseClass = clazz;
        if (fragment == null) {
            try {
                fragment = ProcessBuilder.class.getClassLoader().loadClass("android.support.v4.app.Fragment");
            } catch (Exception e) {
            }
        }
        if (fragmentV4 == null) {
            try {
                fragmentV4 = ProcessBuilder.class.getClassLoader().loadClass("android.app.Fragment");
            } catch (Exception e) {
            }
        }
    }

    public static <T> ProxyBuilder<T> forClass(Class<T> clazz) {
        return new ProxyBuilder<T>(clazz);
    }

    /**
     * Specifies the parent ClassLoader to use when creating the proxy.
     * 
     * <p>
     * If null, {@code ProxyBuilder.class.getClassLoader()} will be used.
     */
    public ProxyBuilder<T> parentClassLoader(ClassLoader parent) {
        parentClassLoader = parent;
        return this;
    }

    public ProxyBuilder<T> handler(InvocationHandler handler) {
        this.handler = handler;
        return this;
    }

    /**
     * Sets the directory where executable code is stored. See {@link DexMaker#generateAndLoad DexMaker.generateAndLoad()} for guidance on choosing a secure location for the dex cache.
     */
    public ProxyBuilder<T> dexCache(File dexCache) {
        this.dexCache = dexCache;
        return this;
    }

    public ProxyBuilder<T> implementing(Class<?>... interfaces) {
        if (interfaces == null || interfaces.length == 0) {
            return this;
        }

        Class[] face = baseClass.getInterfaces();
        List<Class> classes = Arrays.asList(face);
        for (Class<?> i : interfaces) {
            if (i == null || classes.contains(i)) {
                continue;
            }
            if (!i.isInterface()) {
                throw new IllegalArgumentException("Not an interface: " + i.getName());
            }
            this.interfaces.add(i);
        }
        return this;
    }

    public ProxyBuilder<T> constructorArgValues(Object... constructorArgValues) {
        this.constructorArgValues = constructorArgValues;
        return this;
    }

    public ProxyBuilder<T> constructorArgTypes(Class<?>... constructorArgTypes) {
        this.constructorArgTypes = constructorArgTypes;
        return this;
    }

    /**
     * Create a new instance of the class to proxy.
     * 
     * @throws UnsupportedOperationException
     *             if the class we are trying to create a proxy for is not accessible.
     * @throws IOException
     *             if an exception occurred writing to the {@code dexCache} directory.
     * @throws UndeclaredThrowableException
     *             if the constructor for the base class to proxy throws a declared exception during construction.
     * @throws IllegalArgumentException
     *             if the handler is null, if the constructor argument types do not match the constructor argument values, or if no such constructor exists.
     */
    public T build(Application application) throws IOException {
        this.application = application;

        if (handler == null) {
            throw new IllegalArgumentException("handler == null");
        }
        if (constructorArgTypes.length != constructorArgValues.length) {
            throw new IllegalArgumentException("constructorArgValues.length != constructorArgTypes.length");
        }
        Class<? extends T> proxyClass = buildProxyClass();
        if (proxyClass == null) {
            return null;
        }
        Constructor<? extends T> constructor = null;
        try {
            constructor = proxyClass.getConstructor(constructorArgTypes);
        } catch (NoSuchMethodException e) {
            Constructor[] constructors = proxyClass.getConstructors();
            for (Constructor constructor2 : constructors) {
                if (constructor2.getGenericParameterTypes().length == constructorArgTypes.length) {
                    constructor = constructor2;
                    break;
                }
            }
        }
        T result;
        try {
            result = constructor.newInstance(constructorArgValues);
        } catch (InstantiationException e) {
            // Should not be thrown, generated class is not abstract.
            throw new AssertionError(e);
        } catch (IllegalAccessException e) {
            // Should not be thrown, the generated constructor is accessible.
            throw new AssertionError(e);
        } catch (InvocationTargetException e) {
            // Thrown when the base class constructor throws an exception.
            throw launderCause(e);
        }
        setHandlerInstanceField(result, handler);
        return result;
    }

    public Class<? extends T> buildProxyClass(Application application) throws IOException {
        this.application = application;
        return buildProxyClass();
    }

    // TODO: test coverage for this
    // TODO: documentation for this
    public Class<? extends T> buildProxyClass() throws IOException {
        Class<? extends T> proxyClass = null;
        synchronized (baseClass) {
            // we only populate the map with matching types
            proxyClass = (Class) generatedProxyClasses.get(baseClass);
            if (proxyClass != null && proxyClass.getClassLoader().getParent() == parentClassLoader
                    && interfaces.equals(asSet(proxyClass.getInterfaces()))) {
                return proxyClass; // cache hit!
            }
            // ---------------------------------------------------------------------------------------
            // ??class??class
            DexMaker dexMaker = new DexMaker(application);
            String generatedName = getMethodNameForProxyOf(baseClass);

            ClassLoader classLoader = dexMaker.getJarClassLoader(parentClassLoader, dexCache, generatedName);
            ArrayList<MethodEntity> entities = null;
            if (proxy.containsKey(generatedName)) {
                entities = proxy.get(generatedName);
            } else {
                entities = getObject(generatedName);
                if (null != entities) {
                    proxy.put(generatedName, methods);
                }
            }
            Method[] methodsToProxy = null;
            if (classLoader == null || entities == null) {
                // the cache missed; generate the class
                TypeId<? extends T> generatedType = TypeId.get("L" + generatedName + ";");
                TypeId<T> superType = TypeId.get(baseClass);
                generateConstructorsAndFields(dexMaker, generatedType, superType, baseClass);
                methodsToProxy = getMethodsToProxyRecursive();

                generateCodeForAllMethods(dexMaker, generatedType, methodsToProxy, superType);
                dexMaker.declare(generatedType, generatedName + ".generated", PUBLIC, superType,
                        getInterfacesAsTypeIds());

                classLoader = dexMaker.generateAndLoad(parentClassLoader, dexCache, generatedName);

                setObject(generatedName, methods);
                proxy.put(generatedName, methods);
            } else {
                methodsToProxy = new Method[entities.size()];
                int i = 0;
                for (MethodEntity entity : entities) {
                    Method method = null;
                    try {
                        method = entity.clazz.getDeclaredMethod(entity.name, entity.params);
                    } catch (NoSuchMethodException e) {
                        e.printStackTrace();
                    }
                    methodsToProxy[i++] = method;
                }
            }
            try {
                proxyClass = loadClass(classLoader, generatedName);
            } catch (IllegalAccessError e) {
                throw new UnsupportedOperationException("cannot proxy inaccessible class " + baseClass, e);
            } catch (ClassNotFoundException e) {
                throw new AssertionError(e);
            } catch (Exception e) {
                e.printStackTrace();
            }
            setMethodsStaticField(proxyClass, methodsToProxy);
            generatedProxyClasses.put(baseClass, proxyClass);
        }
        return proxyClass;
    }

    // The type cast is safe: the generated type will extend the base class type.
    @SuppressWarnings("unchecked")
    private Class<? extends T> loadClass(ClassLoader classLoader, String generatedName)
            throws ClassNotFoundException {
        return (Class<? extends T>) classLoader.loadClass(generatedName);
    }

    private static RuntimeException launderCause(InvocationTargetException e) {
        Throwable cause = e.getCause();
        // Errors should be thrown as they are.
        if (cause instanceof Error) {
            throw (Error) cause;
        }
        // RuntimeException can be thrown as-is.
        if (cause instanceof RuntimeException) {
            throw (RuntimeException) cause;
        }
        // Declared exceptions will have to be wrapped.
        throw new UndeclaredThrowableException(cause);
    }

    private static void setHandlerInstanceField(Object instance, InvocationHandler handler) {
        try {
            Field handlerField = instance.getClass().getDeclaredField(FIELD_NAME_HANDLER);
            handlerField.setAccessible(true);
            handlerField.set(instance, handler);
        } catch (NoSuchFieldException e) {
            // Should not be thrown, generated proxy class has been generated with this field.
            throw new AssertionError(e);
        } catch (IllegalAccessException e) {
            // Should not be thrown, we just set the field to accessible.
            throw new AssertionError(e);
        }
    }

    private static void setMethodsStaticField(Class<?> proxyClass, Method[] methodsToProxy) {
        try {
            Field methodArrayField = proxyClass.getDeclaredField(FIELD_NAME_METHODS);
            methodArrayField.setAccessible(true);
            methodArrayField.set(null, methodsToProxy);
        } catch (NoSuchFieldException e) {
            // Should not be thrown, generated proxy class has been generated with this field.
            throw new AssertionError(e);
        } catch (IllegalAccessException e) {
            // Should not be thrown, we just set the field to accessible.
            throw new AssertionError(e);
        }
    }

    /**
     * Returns the proxy's {@link InvocationHandler}.
     * 
     * @throws IllegalArgumentException
     *             if the object supplied is not a proxy created by this class.
     */
    public static InvocationHandler getInvocationHandler(Object instance) {
        try {
            Field field = instance.getClass().getDeclaredField(FIELD_NAME_HANDLER);
            field.setAccessible(true);
            return (InvocationHandler) field.get(instance);
        } catch (NoSuchFieldException e) {
            throw new IllegalArgumentException("Not a valid proxy instance", e);
        } catch (IllegalAccessException e) {
            // Should not be thrown, we just set the field to accessible.
            throw new AssertionError(e);
        }
    }

    // TODO: test coverage for isProxyClass

    /**
     * Returns true if {@code c} is a proxy class created by this builder.
     */
    public static boolean isProxyClass(Class<?> c) {
        // TODO: use a marker interface instead?
        try {
            c.getDeclaredField(FIELD_NAME_HANDLER);
            return true;
        } catch (NoSuchFieldException e) {
            return false;
        }
    }

    private static <T, G extends T> void generateCodeForAllMethods(DexMaker dexMaker, TypeId<G> generatedType,
            Method[] methodsToProxy, TypeId<T> superclassType) {
        TypeId<InvocationHandler> handlerType = TypeId.get(InvocationHandler.class);
        TypeId<Method[]> methodArrayType = TypeId.get(Method[].class);
        FieldId<G, InvocationHandler> handlerField = generatedType.getField(handlerType, FIELD_NAME_HANDLER);
        FieldId<G, Method[]> allMethods = generatedType.getField(methodArrayType, FIELD_NAME_METHODS);
        TypeId<Method> methodType = TypeId.get(Method.class);
        TypeId<Object[]> objectArrayType = TypeId.get(Object[].class);
        MethodId<InvocationHandler, Object> methodInvoke = handlerType.getMethod(TypeId.OBJECT, "invoke",
                TypeId.OBJECT, methodType, objectArrayType);
        for (int m = 0; m < methodsToProxy.length; ++m) {
            /*
             * If the 5th method on the superclass Example that can be overridden were to look like this:
             * 
             * public int doSomething(Bar param0, int param1) { ... }
             * 
             * Then the following code will generate a method on the proxy that looks something like this:
             * 
             * public int doSomething(Bar param0, int param1) { int methodIndex = 4; Method[] allMethods = Example_Proxy.$__methodArray; Method thisMethod = allMethods[methodIndex]; int argsLength = 2; Object[] args = new Object[argsLength]; InvocationHandler localHandler = this.$__handler; // for-loop begins int p = 0; Bar parameter0 = param0; args[p] = parameter0; p = 1; int parameter1 = param1; Integer boxed1 = Integer.valueOf(parameter1); args[p] = boxed1; // for-loop ends Object result = localHandler.invoke(this, thisMethod, args); Integer castResult = (Integer) result; int unboxedResult = castResult.intValue(); return unboxedResult; }
             * 
             * Or, in more idiomatic Java:
             * 
             * public int doSomething(Bar param0, int param1) { if ($__handler == null) { return super.doSomething(param0, param1); } return __handler.invoke(this, __methodArray[4], new Object[] { param0, Integer.valueOf(param1) }); }
             */
            Method method = methodsToProxy[m];
            String name = method.getName();
            Class<?>[] argClasses = method.getParameterTypes();
            TypeId<?>[] argTypes = new TypeId<?>[argClasses.length];
            for (int i = 0; i < argTypes.length; ++i) {
                argTypes[i] = TypeId.get(argClasses[i]);
            }
            Class<?> returnType = method.getReturnType();
            TypeId<?> resultType = TypeId.get(returnType);
            MethodId<T, ?> superMethod = superclassType.getMethod(resultType, name, argTypes);
            MethodId<?, ?> methodId = generatedType.getMethod(resultType, name, argTypes);
            Code code = dexMaker.declare(methodId, PUBLIC);
            Local<G> localThis = code.getThis(generatedType);
            Local<InvocationHandler> localHandler = code.newLocal(handlerType);
            Local<Object> invokeResult = code.newLocal(TypeId.OBJECT);
            Local<Integer> intValue = code.newLocal(TypeId.INT);
            Local<Object[]> args = code.newLocal(objectArrayType);
            Local<Integer> argsLength = code.newLocal(TypeId.INT);
            Local<Object> temp = code.newLocal(TypeId.OBJECT);
            Local<?> resultHolder = code.newLocal(resultType);
            Local<Method[]> methodArray = code.newLocal(methodArrayType);
            Local<Method> thisMethod = code.newLocal(methodType);
            Local<Integer> methodIndex = code.newLocal(TypeId.INT);
            Class<?> aBoxedClass = PRIMITIVE_TO_BOXED.get(returnType);
            Local<?> aBoxedResult = null;
            if (aBoxedClass != null) {
                aBoxedResult = code.newLocal(TypeId.get(aBoxedClass));
            }
            Local<?>[] superArgs2 = new Local<?>[argClasses.length];
            Local<?> superResult2 = code.newLocal(resultType);
            Local<InvocationHandler> nullHandler = code.newLocal(handlerType);

            code.loadConstant(methodIndex, m);
            code.sget(allMethods, methodArray);
            code.aget(thisMethod, methodArray, methodIndex);
            code.loadConstant(argsLength, argTypes.length);
            code.newArray(args, argsLength);
            code.iget(handlerField, localHandler, localThis);

            // if (proxy == null)
            code.loadConstant(nullHandler, null);
            Label handlerNullCase = new Label();
            code.compare(Comparison.EQ, handlerNullCase, nullHandler, localHandler);

            // This code is what we execute when we have a valid proxy: delegate to invocation
            // handler.
            for (int p = 0; p < argTypes.length; ++p) {
                code.loadConstant(intValue, p);
                Local<?> parameter = code.getParameter(p, argTypes[p]);
                Local<?> unboxedIfNecessary = boxIfRequired(code, parameter, temp);
                code.aput(args, intValue, unboxedIfNecessary);
            }
            code.invokeInterface(methodInvoke, invokeResult, localHandler, localThis, thisMethod, args);
            generateCodeForReturnStatement(code, returnType, invokeResult, resultHolder, aBoxedResult);

            // This code is executed if proxy is null: call the original super method.
            // This is required to handle the case of construction of an object which leaks the
            // "this" pointer.
            code.mark(handlerNullCase);
            for (int i = 0; i < superArgs2.length; ++i) {
                superArgs2[i] = code.getParameter(i, argTypes[i]);
            }
            if (void.class.equals(returnType)) {
                code.invokeSuper(superMethod, null, localThis, superArgs2);
                code.returnVoid();
            } else {
                invokeSuper(superMethod, code, localThis, superArgs2, superResult2);
                code.returnValue(superResult2);
            }

            /*
             * And to allow calling the original super method, the following is also generated:
             * 
             * public String super$doSomething$java_lang_String(Bar param0, int param1) { int result = super.doSomething(param0, param1); return result; }
             */
            // TODO: don't include a super_ method if the target is abstract!
            MethodId<G, ?> callsSuperMethod = generatedType.getMethod(resultType, superMethodName(method),
                    argTypes);
            Code superCode = dexMaker.declare(callsSuperMethod, PUBLIC);
            Local<G> superThis = superCode.getThis(generatedType);
            Local<?>[] superArgs = new Local<?>[argClasses.length];
            for (int i = 0; i < superArgs.length; ++i) {
                superArgs[i] = superCode.getParameter(i, argTypes[i]);
            }
            if (void.class.equals(returnType)) {
                superCode.invokeSuper(superMethod, null, superThis, superArgs);
                superCode.returnVoid();
            } else {
                Local<?> superResult = superCode.newLocal(resultType);
                invokeSuper(superMethod, superCode, superThis, superArgs, superResult);
                superCode.returnValue(superResult);
            }
        }
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    private static void invokeSuper(MethodId superMethod, Code superCode, Local superThis, Local[] superArgs,
            Local superResult) {
        superCode.invokeSuper(superMethod, superResult, superThis, superArgs);
    }

    private static Local<?> boxIfRequired(Code code, Local<?> parameter, Local<Object> temp) {
        MethodId<?, ?> unboxMethod = PRIMITIVE_TYPE_TO_UNBOX_METHOD.get(parameter.getType());
        if (unboxMethod == null) {
            return parameter;
        }
        code.invokeStatic(unboxMethod, temp, parameter);
        return temp;
    }

    public static Object callSuper(Object proxy, Method method, Object... args) throws Throwable {
        try {
            return proxy.getClass().getMethod(superMethodName(method), method.getParameterTypes()).invoke(proxy,
                    args);
        } catch (InvocationTargetException e) {
            throw e.getCause();
        }
    }

    public static Method getSuper(Object proxy, Method method, Object... args) throws Throwable {
        return proxy.getClass().getMethod(superMethodName(method), method.getParameterTypes());
    }

    /**
     * The super method must include the return type, otherwise its ambiguous for methods with covariant return types.
     */
    private static String superMethodName(Method method) {
        String returnType = method.getReturnType().getName();
        return "super$" + method.getName() + "$" + returnType.replace('.', '_').replace('[', '_').replace(';', '_');
    }

    private static void check(boolean condition, String message) {
        if (!condition) {
            throw new IllegalArgumentException(message);
        }
    }

    private static <T, G extends T> void generateConstructorsAndFields(DexMaker dexMaker, TypeId<G> generatedType,
            TypeId<T> superType, Class<T> superClass) {
        TypeId<InvocationHandler> handlerType = TypeId.get(InvocationHandler.class);
        TypeId<Method[]> methodArrayType = TypeId.get(Method[].class);
        FieldId<G, InvocationHandler> handlerField = generatedType.getField(handlerType, FIELD_NAME_HANDLER);
        dexMaker.declare(handlerField, PRIVATE, null);
        FieldId<G, Method[]> allMethods = generatedType.getField(methodArrayType, FIELD_NAME_METHODS);
        dexMaker.declare(allMethods, PRIVATE | STATIC, null);
        for (Constructor<T> constructor : getConstructorsToOverwrite(superClass)) {
            if (constructor.getModifiers() == Modifier.FINAL) {
                continue;
            }
            TypeId<?>[] types = classArrayToTypeArray(constructor.getParameterTypes());
            MethodId<?, ?> method = generatedType.getConstructor(types);
            Code constructorCode = dexMaker.declare(method, PUBLIC);
            Local<G> thisRef = constructorCode.getThis(generatedType);
            Local<?>[] params = new Local[types.length];
            for (int i = 0; i < params.length; ++i) {
                params[i] = constructorCode.getParameter(i, types[i]);
            }
            MethodId<T, ?> superConstructor = superType.getConstructor(types);
            constructorCode.invokeDirect(superConstructor, null, thisRef, params);
            constructorCode.returnVoid();
        }
    }

    // The type parameter on Constructor is the class in which the constructor is declared.
    // The getDeclaredConstructors() method gets constructors declared only in the given class,
    // hence this cast is safe.
    @SuppressWarnings("unchecked")
    private static <T> Constructor<T>[] getConstructorsToOverwrite(Class<T> clazz) {
        return (Constructor<T>[]) clazz.getDeclaredConstructors();
    }

    private TypeId<?>[] getInterfacesAsTypeIds() {
        TypeId<?>[] result = new TypeId<?>[interfaces.size()];
        int i = 0;
        for (Class<?> implemented : interfaces) {
            result[i++] = TypeId.get(implemented);
        }
        return result;
    }

    /**
     * Gets all {@link Method} objects we can proxy in the hierarchy of the supplied class.
     */
    private Method[] getMethodsToProxyRecursive() {
        methods.clear();
        Set<MethodSetEntry> methodsToProxy = new HashSet<MethodSetEntry>();
        Set<MethodSetEntry> seenFinalMethods = new HashSet<MethodSetEntry>();
        for (Class<?> c = baseClass; c != null && c != Object.class && c != fragment
                && c != fragmentV4; c = c.getSuperclass()) {
            getMethodsToProxy(methodsToProxy, seenFinalMethods, c);
        }
        for (Class<?> c : interfaces) {
            getMethodsToProxy(methodsToProxy, seenFinalMethods, c);
        }

        Method[] results = new Method[methodsToProxy.size()];
        int i = 0;
        for (MethodEntity entry : methods) {
            results[i++] = entry.method;
        }
        return results;
    }

    private void getMethodsToProxy(Set<MethodSetEntry> sink, Set<MethodSetEntry> seenFinalMethods, Class<?> c) {
        for (Method method : c.getDeclaredMethods()) {
            for (Class<? extends Annotation> annotation : Constants.annotation) {
                if (method.getAnnotation(annotation) != null) {
                    MethodSetEntry entry = new MethodSetEntry(method);
                    if (seenFinalMethods.contains(entry)) {
                        continue;
                    }
                    if (sink.add(entry)) {
                        MethodEntity entity = new MethodEntity();
                        entity.clazz = c;
                        entity.name = method.getName();
                        entity.params = method.getParameterTypes();
                        entity.method = method;
                        methods.add(entity);
                    }
                }
            }

            if (!Constants.method.contains(method.getName())) {
                // ??
                continue;
            }
            if ((method.getModifiers() & Modifier.FINAL) != 0) {
                // Skip final methods, we can't override them. We
                // also need to remember them, in case the same
                // method exists in a parent class.
                seenFinalMethods.add(new MethodSetEntry(method));
                continue;
            }

            if ((method.getModifiers() & STATIC) != 0) {
                // Skip static methods, overriding them has no effect.
                continue;
            }
            if ((method.getModifiers() & PRIVATE) != 0) {
                // Skip static methods, overriding them has no effect.
                continue;
            }
            //         if ((method.getModifiers() & Modifier.PROTECTED) != 0) {
            //            // Skip static methods, overriding them has no effect.
            //            continue;
            //         }
            if (method.getName().equals("finalize") && method.getParameterTypes().length == 0) {
                // Skip finalize method, it's likely important that it execute as normal.
                continue;
            }
            MethodSetEntry entry = new MethodSetEntry(method);
            if (seenFinalMethods.contains(entry)) {
                // This method is final in a child class.
                // We can't override it.
                continue;
            }
            if (sink.add(entry)) {
                MethodEntity entity = new MethodEntity();
                entity.clazz = c;
                entity.name = method.getName();
                entity.params = method.getParameterTypes();
                entity.method = method;
                methods.add(entity);
            }
        }

        for (Class<?> i : c.getInterfaces()) {
            getMethodsToProxy(sink, seenFinalMethods, i);
        }
    }

    private static <T> String getMethodNameForProxyOf(Class<T> clazz) {
        return clazz.getSimpleName() + "_Proxy";
    }

    private static TypeId<?>[] classArrayToTypeArray(Class<?>[] input) {
        TypeId<?>[] result = new TypeId[input.length];
        for (int i = 0; i < input.length; ++i) {
            result[i] = TypeId.get(input[i]);
        }
        return result;
    }

    /**
     * Calculates the correct return statement code for a method.
     * <p>
     * A void method will not return anything. A method that returns a primitive will need to unbox the boxed result. Otherwise we will cast the result.
     */
    // This one is tricky to fix, I gave up.
    @SuppressWarnings({ "rawtypes", "unchecked" })
    private static void generateCodeForReturnStatement(Code code, Class methodReturnType,
            Local localForResultOfInvoke, Local localOfMethodReturnType, Local aBoxedResult) {
        if (PRIMITIVE_TO_UNBOX_METHOD.containsKey(methodReturnType)) {
            code.cast(aBoxedResult, localForResultOfInvoke);
            MethodId unboxingMethodFor = getUnboxMethodForPrimitive(methodReturnType);
            code.invokeVirtual(unboxingMethodFor, localOfMethodReturnType, aBoxedResult);
            code.returnValue(localOfMethodReturnType);
        } else if (void.class.equals(methodReturnType)) {
            code.returnVoid();
        } else {
            code.cast(localOfMethodReturnType, localForResultOfInvoke);
            code.returnValue(localOfMethodReturnType);
        }
    }

    private static <T> Set<T> asSet(T... array) {
        return new CopyOnWriteArraySet<T>(Arrays.asList(array));
    }

    private static MethodId<?, ?> getUnboxMethodForPrimitive(Class<?> methodReturnType) {
        return PRIMITIVE_TO_UNBOX_METHOD.get(methodReturnType);
    }

    private static final Map<Class<?>, Class<?>> PRIMITIVE_TO_BOXED;
    static {
        PRIMITIVE_TO_BOXED = new HashMap<Class<?>, Class<?>>();
        PRIMITIVE_TO_BOXED.put(boolean.class, Boolean.class);
        PRIMITIVE_TO_BOXED.put(int.class, Integer.class);
        PRIMITIVE_TO_BOXED.put(byte.class, Byte.class);
        PRIMITIVE_TO_BOXED.put(long.class, Long.class);
        PRIMITIVE_TO_BOXED.put(short.class, Short.class);
        PRIMITIVE_TO_BOXED.put(float.class, Float.class);
        PRIMITIVE_TO_BOXED.put(double.class, Double.class);
        PRIMITIVE_TO_BOXED.put(char.class, Character.class);
    }

    private static final Map<TypeId<?>, MethodId<?, ?>> PRIMITIVE_TYPE_TO_UNBOX_METHOD;
    static {
        PRIMITIVE_TYPE_TO_UNBOX_METHOD = new HashMap<TypeId<?>, MethodId<?, ?>>();
        for (Map.Entry<Class<?>, Class<?>> entry : PRIMITIVE_TO_BOXED.entrySet()) {
            TypeId<?> primitiveType = TypeId.get(entry.getKey());
            TypeId<?> boxedType = TypeId.get(entry.getValue());
            MethodId<?, ?> valueOfMethod = boxedType.getMethod(boxedType, "valueOf", primitiveType);
            PRIMITIVE_TYPE_TO_UNBOX_METHOD.put(primitiveType, valueOfMethod);
        }
    }

    /**
     * Map from primitive type to method used to unbox a boxed version of the primitive.
     * <p>
     * This is required for methods whose return type is primitive, since the {@link InvocationHandler} will return us a boxed result, and we'll need to convert it back to primitive value.
     */
    private static final Map<Class<?>, MethodId<?, ?>> PRIMITIVE_TO_UNBOX_METHOD;
    static {
        Map<Class<?>, MethodId<?, ?>> map = new HashMap<Class<?>, MethodId<?, ?>>();
        map.put(boolean.class, TypeId.get(Boolean.class).getMethod(TypeId.BOOLEAN, "booleanValue"));
        map.put(int.class, TypeId.get(Integer.class).getMethod(TypeId.INT, "intValue"));
        map.put(byte.class, TypeId.get(Byte.class).getMethod(TypeId.BYTE, "byteValue"));
        map.put(long.class, TypeId.get(Long.class).getMethod(TypeId.LONG, "longValue"));
        map.put(short.class, TypeId.get(Short.class).getMethod(TypeId.SHORT, "shortValue"));
        map.put(float.class, TypeId.get(Float.class).getMethod(TypeId.FLOAT, "floatValue"));
        map.put(double.class, TypeId.get(Double.class).getMethod(TypeId.DOUBLE, "doubleValue"));
        map.put(char.class, TypeId.get(Character.class).getMethod(TypeId.CHAR, "charValue"));
        PRIMITIVE_TO_UNBOX_METHOD = map;
    }

    /**
     * Wrapper class to let us disambiguate {@link Method} objects.
     * <p>
     * The purpose of this class is to override the {@link #equals(Object)} and {@link #hashCode()} methods so we can use a {@link Set} to remove duplicate methods that are overrides of one another. For these purposes, we consider two methods to be equal if they have the same name, return type, and parameter types.
     */
    private static class MethodSetEntry {
        private final String name;
        private final Class<?>[] paramTypes;
        private final Class<?> returnType;
        private final Method originalMethod;

        public MethodSetEntry(Method method) {
            originalMethod = method;
            name = method.getName();
            paramTypes = method.getParameterTypes();
            returnType = method.getReturnType();
        }

        @Override
        public boolean equals(Object o) {
            if (o instanceof MethodSetEntry) {
                MethodSetEntry other = (MethodSetEntry) o;
                return name.equals(other.name) && returnType.equals(other.returnType)
                        && Arrays.equals(paramTypes, other.paramTypes);
            }
            return false;
        }

        @Override
        public int hashCode() {
            int result = 17;
            result += 31 * result + name.hashCode();
            result += 31 * result + returnType.hashCode();
            result += 31 * result + Arrays.hashCode(paramTypes);
            return result;
        }
    }

    public void setObject(String fileName, Serializable object) {
        long time = System.currentTimeMillis();
        FileOutputStream fos = null;
        ObjectOutputStream oos = null;
        try {
            fos = application.openFileOutput(fileName, Context.MODE_PRIVATE);
            oos = new ObjectOutputStream(fos);
            oos.writeObject(object);// 
        } catch (Exception e) {
            e.printStackTrace();
            ;
        } finally {
            try {
                if (fos != null) {
                    fos.close();
                }
                if (oos != null) {
                    oos.close();
                }
            } catch (IOException e) {
            }
        }
    }

    public <T> T getObject(String fileName) {
        long time = System.currentTimeMillis();
        FileInputStream fis = null;
        ObjectInputStream ois = null;
        try {
            if (!new File(fileName).exists()) {
                return null;
            }
            fis = application.openFileInput(fileName); // ?
            ois = new ObjectInputStream(fis);
            return (T) ois.readObject();
        } catch (Exception e) {
        } finally {
            try {
                if (fis != null) {
                    fis.close();
                }
                if (ois != null) {
                    ois.close();
                }
            } catch (IOException e) {
            }
        }
        return null;
    }
}