/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.openejb.util.proxy;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
import org.apache.xbean.asm.ClassWriter;
import org.apache.xbean.asm.FieldVisitor;
import org.apache.xbean.asm.Label;
import org.apache.xbean.asm.MethodVisitor;
import org.apache.xbean.asm.Opcodes;
import org.apache.xbean.asm.Type;
public class LocalBeanProxyGeneratorImpl implements LocalBeanProxyGenerator, Opcodes {
private static final sun.misc.Unsafe unsafe;
static {
unsafe = (sun.misc.Unsafe) AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
try {
Field field = sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
field.setAccessible(true);
return field.get(null);
} catch (Exception e) {
throw new IllegalStateException("Cannot get sun.misc.Unsafe", e);
}
}
});
}
public Class createProxy(Class<?> clsToProxy, ClassLoader cl) {
String proxyName = generateProxyName(clsToProxy.getName());
return createProxy(clsToProxy, proxyName, cl);
}
private String generateProxyName(String clsName) {
return clsName + "$LocalBeanProxy";
}
private Class createProxy(Class<?> clsToProxy, String proxyName, ClassLoader cl) {
String clsName = proxyName.replaceAll("\\.", "/");
try {
return cl.loadClass(proxyName);
} catch (Exception e) {
}
try {
byte[] proxyBytes = generateProxy(clsToProxy, clsName);
return (Class<?>) unsafe.defineClass(proxyName, proxyBytes, 0, proxyBytes.length, clsToProxy.getClassLoader(), clsToProxy.getProtectionDomain());
} catch (ProxyGenerationException e) {
throw new InternalError(e.toString());
}
}
private byte[] generateProxy(Class<?> clsToProxy, String proxyName) throws ProxyGenerationException {
ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
FieldVisitor fv;
MethodVisitor mv;
String clsToOverride = clsToProxy.getName().replaceAll("\\.", "/");
String proxyClassName = proxyName.replaceAll("\\.", "/");
// push class signature
cw.visit(V1_5, ACC_PUBLIC + ACC_SUPER, proxyClassName, null, clsToOverride, null);
cw.visitSource(clsToOverride + ".java", null);
// push InvocationHandler field
fv = cw.visitField(ACC_FINAL + ACC_PRIVATE, "invocationHandler", "Ljava/lang/reflect/InvocationHandler;", null, null);
fv.visitEnd();
// push constructor
mv = cw.visitMethod(ACC_PUBLIC, "<init>", "(Ljava/lang/reflect/InvocationHandler;)V", null, null);
mv.visitCode();
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, clsToOverride, "<init>", "()V");
mv.visitVarInsn(ALOAD, 0);
mv.visitVarInsn(ALOAD, 1);
mv.visitFieldInsn(PUTFIELD, proxyName, "invocationHandler", "Ljava/lang/reflect/InvocationHandler;");
mv.visitInsn(RETURN);
mv.visitMaxs(0, 0);
mv.visitEnd();
// loop through public methods, and push something to the class
Method[] methods = clsToProxy.getDeclaredMethods();
for (Method method : methods) {
processMethod(cw, method, proxyClassName, clsToOverride);
}
byte[] clsBytes = cw.toByteArray();
return clsBytes;
}
private void processMethod(ClassWriter cw, Method method, String proxyName, String clsToOverride) throws ProxyGenerationException {
if ("<init>".equals(method.getName())) {
return;
}
Class<?> returnType = method.getReturnType();
Class<?>[] parameterTypes = method.getParameterTypes();
Class<?>[] exceptionTypes = method.getExceptionTypes();
// push the method definition
MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, method.getName(), getMethodSignatureAsString(returnType, parameterTypes), null, null);
mv.visitCode();
// push try/catch block, to catch declared exceptions, and to catch java.lang.Throwable
Label l0 = new Label();
Label l1 = new Label();
Label l2 = new Label();
Label l3 = new Label();
if (exceptionTypes.length > 0) {
mv.visitTryCatchBlock(l0, l1, l2, "java/lang/reflect/InvocationTargetException");
}
// mv.visitTryCatchBlock(l0, l1, l3, "java/lang/Throwable");
// push try code
mv.visitLabel(l0);
mv.visitLdcInsn(Type.getType("L" + clsToOverride + ";"));
// the following code generates the bytecode for this line of Java:
// Method method = <proxy>.class.getMethod("add", new Class[] { <array of function argument classes> });
// get the method name to invoke, and push to stack
mv.visitLdcInsn(method.getName());
// create the Class[]
createArrayDefinition(mv, parameterTypes.length, Class.class);
int length = 1;
// push parameters into array
for (int i = 0; i < parameterTypes.length; i++) {
// keep copy of array on stack
mv.visitInsn(DUP);
Class<?> parameterType = parameterTypes[i];
// push number onto stack
pushIntOntoStack(mv, i);
if (parameterType.isPrimitive()) {
String wrapperType = getWrapperType(parameterType);
mv.visitFieldInsn(GETSTATIC, wrapperType, "TYPE", "Ljava/lang/Class;");
} else {
mv.visitLdcInsn(Type.getType(getAsmTypeAsString(parameterType, true)));
}
mv.visitInsn(AASTORE);
if (Long.TYPE.equals(parameterType) || Double.TYPE.equals(parameterType)) {
length += 2;
} else {
length++;
}
}
// invoke getMethod() with the method name and the array of types
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Class", "getMethod", "(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Method;");
// store the returned method for later
mv.visitVarInsn(ASTORE, length);
// the following code generates bytecode equivalent to:
// return ((<returntype>) invocationHandler.invoke(this, method, new Object[] { <function arguments }))[.<primitive>Value()];
Label l4 = new Label();
mv.visitLabel(l4);
mv.visitVarInsn(ALOAD, 0);
// get the invocationHandler field from this class
mv.visitFieldInsn(GETFIELD, proxyName, "invocationHandler", "Ljava/lang/reflect/InvocationHandler;");
// we want to pass "this" in as the first parameter
mv.visitVarInsn(ALOAD, 0);
// and the method we fetched earlier
mv.visitVarInsn(ALOAD, length);
// need to construct the array of objects passed in
// create the Object[]
createArrayDefinition(mv, parameterTypes.length, Object.class);
int index = 1;
// push parameters into array
for (int i = 0; i < parameterTypes.length; i++) {
// keep copy of array on stack
mv.visitInsn(DUP);
Class<?> parameterType = parameterTypes[i];
// push number onto stack
pushIntOntoStack(mv, i);
if (parameterType.isPrimitive()) {
String wrapperType = getWrapperType(parameterType);
mv.visitVarInsn(getVarInsn(parameterType), index);
mv.visitMethodInsn(INVOKESTATIC, wrapperType, "valueOf", "(" + getPrimitiveLetter(parameterType) + ")L" + wrapperType + ";");
mv.visitInsn(AASTORE);
if (Long.TYPE.equals(parameterType) || Double.TYPE.equals(parameterType)) {
index += 2;
} else {
index++;
}
} else {
mv.visitVarInsn(ALOAD, index);
mv.visitInsn(AASTORE);
index++;
}
}
// invoke the invocationHandler
mv.visitMethodInsn(INVOKEINTERFACE, "java/lang/reflect/InvocationHandler", "invoke", "(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;");
// cast the result
mv.visitTypeInsn(CHECKCAST, getCastType(returnType));
if (returnType.isPrimitive() && (!Void.TYPE.equals(returnType))) {
// get the primitive value
mv.visitMethodInsn(INVOKEVIRTUAL, getWrapperType(returnType), getPrimitiveMethod(returnType), "()" + getPrimitiveLetter(returnType));
}
// push return
mv.visitLabel(l1);
if (! Void.TYPE.equals(returnType)) {
mv.visitInsn(getReturnInsn(returnType));
} else {
mv.visitInsn(POP);
mv.visitInsn(RETURN);
}
// catch InvocationTargetException
if (exceptionTypes.length > 0) {
mv.visitLabel(l2);
mv.visitVarInsn(ASTORE, length);
Label l5 = new Label();
mv.visitLabel(l5);
for (int i = 0; i < exceptionTypes.length; i++) {
Class<?> exceptionType = exceptionTypes[i];
mv.visitLdcInsn(Type.getType("L" + exceptionType.getCanonicalName().replaceAll("\\.", "/") + ";"));
mv.visitVarInsn(ALOAD, length);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/reflect/InvocationTargetException", "getCause", "()Ljava/lang/Throwable;");
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;");
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z");
Label l6 = new Label();
mv.visitJumpInsn(IFEQ, l6);
Label l7 = new Label();
mv.visitLabel(l7);
mv.visitVarInsn(ALOAD, length);
mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/reflect/InvocationTargetException", "getCause", "()Ljava/lang/Throwable;");
mv.visitTypeInsn(CHECKCAST, exceptionType.getCanonicalName().replaceAll("\\.", "/"));
mv.visitInsn(ATHROW);
mv.visitLabel(l6);
if (i == (exceptionTypes.length - 1)) {
mv.visitTypeInsn(NEW, "java/lang/reflect/UndeclaredThrowableException");
mv.visitInsn(DUP);
mv.visitVarInsn(ALOAD, length);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/reflect/UndeclaredThrowableException", "<init>", "(Ljava/lang/Throwable;)V");
mv.visitInsn(ATHROW);
}
}
}
// finish this method
mv.visitMaxs(0, 0);
mv.visitEnd();
}
/**
* Gets the appropriate bytecode instruction for RETURN, according to what type we need to return
* @param type Type the needs to be returned
* @return The matching bytecode instruction
*/
private int getReturnInsn(Class<?> type) {
if (type.isPrimitive()) {
if (Integer.TYPE.equals(type)) {
return IRETURN;
} else if (Boolean.TYPE.equals(type)) {
return IRETURN;
} else if (Character.TYPE.equals(type)) {
return IRETURN;
} else if (Byte.TYPE.equals(type)) {
return IRETURN;
} else if (Short.TYPE.equals(type)) {
return IRETURN;
} else if (Float.TYPE.equals(type)) {
return FRETURN;
} else if (Long.TYPE.equals(type)) {
return LRETURN;
} else if (Double.TYPE.equals(type)) {
return DRETURN;
}
}
return ARETURN;
}
/**
* Returns the appropriate bytecode instruction to load a value from a variable to the stack
* @param type Type to load
* @return Bytecode instruction to use
*/
private int getVarInsn(Class<?> type) {
if (type.isPrimitive()) {
if (Integer.TYPE.equals(type)) {
return ILOAD;
} else if (Boolean.TYPE.equals(type)) {
return ILOAD;
} else if (Character.TYPE.equals(type)) {
return ILOAD;
} else if (Byte.TYPE.equals(type)) {
return ILOAD;
} else if (Short.TYPE.equals(type)) {
return ILOAD;
} else if (Float.TYPE.equals(type)) {
return FLOAD;
} else if (Long.TYPE.equals(type)) {
return LLOAD;
} else if (Double.TYPE.equals(type)) {
return DLOAD;
}
}
throw new IllegalStateException("Type: " + type.getCanonicalName() + " is not a primitive type");
}
/**
* Returns the name of the Java method to call to get the primitive value from an Object - e.g. intValue for java.lang.Integer
* @param type Type whose primitive method we want to lookup
* @return The name of the method to use
*/
private String getPrimitiveMethod(Class<?> type) {
if (Integer.TYPE.equals(type)) {
return "intValue";
} else if (Boolean.TYPE.equals(type)) {
return "booleanValue";
} else if (Character.TYPE.equals(type)) {
return "charValue";
} else if (Byte.TYPE.equals(type)) {
return "byteValue";
} else if (Short.TYPE.equals(type)) {
return "shortValue";
} else if (Float.TYPE.equals(type)) {
return "floatValue";
} else if (Long.TYPE.equals(type)) {
return "longValue";
} else if (Double.TYPE.equals(type)) {
return "doubleValue";
}
throw new IllegalStateException("Type: " + type.getCanonicalName() + " is not a primitive type");
}
/**
* Gets the string to use for CHECKCAST instruction, returning the correct value for any type, including primitives and arrays
* @param returnType The type to cast to with CHECKCAST
* @return CHECKCAST parameter
*/
String getCastType(Class<?> returnType) {
if (returnType.isPrimitive()) {
return getWrapperType(returnType);
} else {
return getAsmTypeAsString(returnType, false);
}
}
/**
* Returns the wrapper type for a primitive, e.g. java.lang.Integer for int
* @param type
* @return
*/
private String getWrapperType(Class<?> type) {
if (Integer.TYPE.equals(type)) {
return Integer.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Boolean.TYPE.equals(type)) {
return Boolean.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Character.TYPE.equals(type)) {
return Character.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Byte.TYPE.equals(type)) {
return Byte.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Short.TYPE.equals(type)) {
return Short.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Float.TYPE.equals(type)) {
return Float.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Long.TYPE.equals(type)) {
return Long.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Double.TYPE.equals(type)) {
return Double.class.getCanonicalName().replaceAll("\\.", "/");
} else if (Void.TYPE.equals(type)) {
return Void.class.getCanonicalName().replaceAll("\\.", "/");
}
throw new IllegalStateException("Type: " + type.getCanonicalName() + " is not a primitive type");
}
/**
* Invokes the most appropriate bytecode instruction to put a number on the stack
* @param mv
* @param i
*/
private void pushIntOntoStack(MethodVisitor mv, int i) {
if (i == 0) {
mv.visitInsn(ICONST_0);
} else if (i == 1) {
mv.visitInsn(ICONST_1);
} else if (i == 2) {
mv.visitInsn(ICONST_2);
} else if (i == 3) {
mv.visitInsn(ICONST_3);
} else if (i == 4) {
mv.visitInsn(ICONST_4);
} else if (i == 5) {
mv.visitInsn(ICONST_5);
} else if (i > 5 && i <= 255) {
mv.visitIntInsn(BIPUSH, i);
} else {
mv.visitIntInsn(SIPUSH, i);
}
}
/**
* pushes an array of the specified size to the method visitor. The generated bytecode will leave
* the new array at the top of the stack.
*
* @param mv MethodVisitor to use
* @param size Size of the array to create
* @param type Type of array to create
* @throws ProxyGenerationException
*/
private void createArrayDefinition(MethodVisitor mv, int size, Class<?> type) throws ProxyGenerationException {
// create a new array of java.lang.class (2)
if (size < 0) {
throw new ProxyGenerationException("Array size cannot be less than zero");
}
pushIntOntoStack(mv, size);
mv.visitTypeInsn(ANEWARRAY, type.getCanonicalName().replaceAll("\\.", "/"));
}
String getMethodSignatureAsString(Class<?> returnType, Class<?>[] parameterTypes) {
StringBuilder builder = new StringBuilder();
builder.append("(");
for (Class<?> parameterType : parameterTypes) {
builder.append(getAsmTypeAsString(parameterType, true));
}
builder.append(")");
builder.append(getAsmTypeAsString(returnType, true));
return builder.toString();
}
/**
* Returns the single letter that matches the given primitive in bytecode instructions
* @param type
* @return
*/
private String getPrimitiveLetter(Class<?> type) {
if (Integer.TYPE.equals(type)) {
return "I";
} else if (Void.TYPE.equals(type)) {
return "V";
} else if (Boolean.TYPE.equals(type)) {
return "Z";
} else if (Character.TYPE.equals(type)) {
return "C";
} else if (Byte.TYPE.equals(type)) {
return "B";
} else if (Short.TYPE.equals(type)) {
return "S";
} else if (Float.TYPE.equals(type)) {
return "F";
} else if (Long.TYPE.equals(type)) {
return "J";
} else if (Double.TYPE.equals(type)) {
return "D";
}
throw new IllegalStateException("Type: " + type.getCanonicalName() + " is not a primitive type");
}
/**
* Converts a class to a String suitable for ASM.
* @param parameterType Class to convert
* @param wrap True if a non-array object should be wrapped with L and ; - e.g. Ljava/lang/Integer;
* @return String to use for ASM
*/
public String getAsmTypeAsString(Class<?> parameterType, boolean wrap) {
if (parameterType.isArray()) {
if (parameterType.getComponentType().isPrimitive()) {
Class<?> componentType = parameterType.getComponentType();
return "[" + getPrimitiveLetter(componentType);
} else {
return "[" + getAsmTypeAsString(parameterType.getComponentType(), true);
}
} else {
if (! parameterType.isPrimitive()) {
String clsName = parameterType.getCanonicalName();
if (parameterType.isMemberClass()) {
int lastDot = clsName.lastIndexOf(".");
clsName = clsName.substring(0, lastDot) + "$" + clsName.substring(lastDot + 1);
}
if (wrap) {
return "L" + clsName.replaceAll("\\.", "/") + ";";
} else {
return clsName.replaceAll("\\.", "/");
}
} else {
return getPrimitiveLetter(parameterType);
}
}
}
}