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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package com.feilong.lib.javassist.util.proxy;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.reflect.Method;
import java.security.ProtectionDomain;
import java.util.List;
import com.feilong.lib.javassist.CannotCompileException;
import com.feilong.lib.javassist.bytecode.ClassFile;
/**
* Helper class for invoking {@link ClassLoader#defineClass(String,byte[],int,int)}.
*
* @since 3.22
*/
public class DefineClassHelper{
private static abstract class Helper{
abstract Class defineClass(
String name,
byte[] b,
int off,
int len,
Class neighbor,
ClassLoader loader,
ProtectionDomain protectionDomain) throws ClassFormatError,CannotCompileException;
}
private static class Java9 extends Helper{
final class ReferencedUnsafe{
private final SecurityActions.TheUnsafe sunMiscUnsafeTheUnsafe;
private final MethodHandle defineClass;
ReferencedUnsafe(SecurityActions.TheUnsafe usf, MethodHandle meth){
this.sunMiscUnsafeTheUnsafe = usf;
this.defineClass = meth;
}
Class defineClass(String name,byte[] b,int off,int len,ClassLoader loader,ProtectionDomain protectionDomain)
throws ClassFormatError{
try{
if (getCallerClass.invoke(stack) != Java9.class){
throw new IllegalAccessError("Access denied for caller.");
}
}catch (Exception e){
throw new RuntimeException("cannot initialize", e);
}
try{
return (Class) defineClass
.invokeWithArguments(sunMiscUnsafeTheUnsafe.theUnsafe, name, b, off, len, loader, protectionDomain);
}catch (Throwable e){
if (e instanceof RuntimeException){
throw (RuntimeException) e;
}
if (e instanceof ClassFormatError){
throw (ClassFormatError) e;
}
throw new ClassFormatError(e.getMessage());
}
}
}
private final Object stack;
private final Method getCallerClass;
private final ReferencedUnsafe sunMiscUnsafe = getReferencedUnsafe();
Java9(){
Class stackWalkerClass = null;
try{
stackWalkerClass = Class.forName("java.lang.StackWalker");
}catch (ClassNotFoundException e){
// Skip initialization when the class doesn't exist i.e. we are on JDK < 9
}
if (stackWalkerClass != null){
try{
Class optionClass = Class.forName("java.lang.StackWalker$Option");
stack = stackWalkerClass.getMethod("getInstance", optionClass)
// The first one is RETAIN_CLASS_REFERENCE
.invoke(null, optionClass.getEnumConstants()[0]);
getCallerClass = stackWalkerClass.getMethod("getCallerClass");
}catch (Throwable e){
throw new RuntimeException("cannot initialize", e);
}
}else{
stack = null;
getCallerClass = null;
}
}
private final ReferencedUnsafe getReferencedUnsafe(){
try{
if (privileged != null && getCallerClass.invoke(stack) != this.getClass()){
throw new IllegalAccessError("Access denied for caller.");
}
}catch (Exception e){
throw new RuntimeException("cannot initialize", e);
}
try{
SecurityActions.TheUnsafe usf = SecurityActions.getSunMiscUnsafeAnonymously();
List defineClassMethod = usf.methods.get("defineClass");
// On Java 11+ the defineClass method does not exist anymore
if (null == defineClassMethod){
return null;
}
MethodHandle meth = MethodHandles.lookup().unreflect(defineClassMethod.get(0));
return new ReferencedUnsafe(usf, meth);
}catch (Throwable e){
throw new RuntimeException("cannot initialize", e);
}
}
@Override
Class defineClass(String name,byte[] b,int off,int len,Class neighbor,ClassLoader loader,ProtectionDomain protectionDomain)
throws ClassFormatError{
try{
if (getCallerClass.invoke(stack) != DefineClassHelper.class){
throw new IllegalAccessError("Access denied for caller.");
}
}catch (Exception e){
throw new RuntimeException("cannot initialize", e);
}
return sunMiscUnsafe.defineClass(name, b, off, len, loader, protectionDomain);
}
}
private static class Java7 extends Helper{
private final SecurityActions stack = SecurityActions.stack;
private final MethodHandle defineClass = getDefineClassMethodHandle();
private final MethodHandle getDefineClassMethodHandle(){
if (privileged != null && stack.getCallerClass() != this.getClass()){
throw new IllegalAccessError("Access denied for caller.");
}
try{
return SecurityActions.getMethodHandle(
ClassLoader.class,
"defineClass",
new Class[] { String.class, byte[].class, int.class, int.class, ProtectionDomain.class });
}catch (NoSuchMethodException e){
throw new RuntimeException("cannot initialize", e);
}
}
@Override
Class defineClass(String name,byte[] b,int off,int len,Class neighbor,ClassLoader loader,ProtectionDomain protectionDomain)
throws ClassFormatError{
if (stack.getCallerClass() != DefineClassHelper.class){
throw new IllegalAccessError("Access denied for caller.");
}
try{
return (Class) defineClass.invokeWithArguments(loader, name, b, off, len, protectionDomain);
}catch (Throwable e){
if (e instanceof RuntimeException){
throw (RuntimeException) e;
}
if (e instanceof ClassFormatError){
throw (ClassFormatError) e;
}
throw new ClassFormatError(e.getMessage());
}
}
}
private static class JavaOther extends Helper{
private final Method defineClass = getDefineClassMethod();
private final SecurityActions stack = SecurityActions.stack;
private final Method getDefineClassMethod(){
if (privileged != null && stack.getCallerClass() != this.getClass()){
throw new IllegalAccessError("Access denied for caller.");
}
try{
return SecurityActions.getDeclaredMethod(
ClassLoader.class,
"defineClass",
new Class[] { String.class, byte[].class, int.class, int.class, ProtectionDomain.class });
}catch (NoSuchMethodException e){
throw new RuntimeException("cannot initialize", e);
}
}
@Override
Class defineClass(String name,byte[] b,int off,int len,Class neighbor,ClassLoader loader,ProtectionDomain protectionDomain)
throws ClassFormatError,CannotCompileException{
Class klass = stack.getCallerClass();
if (klass != DefineClassHelper.class && klass != this.getClass()){
throw new IllegalAccessError("Access denied for caller.");
}
try{
SecurityActions.setAccessible(defineClass, true);
return (Class) defineClass.invoke(loader, new Object[] { name, b, off, len, protectionDomain });
}catch (Throwable e){
if (e instanceof ClassFormatError){
throw (ClassFormatError) e;
}
if (e instanceof RuntimeException){
throw (RuntimeException) e;
}
throw new CannotCompileException(e);
}finally{
SecurityActions.setAccessible(defineClass, false);
}
}
}
// Java 11+ removed sun.misc.Unsafe.defineClass, so we fallback to invoking defineClass on
// ClassLoader until we have an implementation that uses MethodHandles.Lookup.defineClass
private static final Helper privileged = ClassFile.MAJOR_VERSION >= ClassFile.JAVA_9 ? new Java9()
: ClassFile.MAJOR_VERSION >= ClassFile.JAVA_7 ? new Java7() : new JavaOther();
/**
* Loads a class file by a given class loader.
*
*
* This first tries to use {@code java.lang.invoke.MethodHandle} to load a class.
* Otherwise, or if {@code neighbor} is null,
* this tries to use {@code sun.misc.Unsafe} to load a class.
* Then it tries to use a {@code protected} method in {@code java.lang.ClassLoader}
* via {@code PrivilegedAction}. Since the latter approach is not available
* any longer by default in Java 9 or later, the JVM argument
* {@code --add-opens java.base/java.lang=ALL-UNNAMED} must be given to the JVM.
* If this JVM argument cannot be given, {@link #toPublicClass(String,byte[])}
* should be used instead.
*
*
* @param className
* the name of the loaded class.
* @param neighbor
* the class contained in the same package as the loaded class.
* @param loader
* the class loader. It can be null if {@code neighbor} is not null
* and the JVM is Java 11 or later.
* @param domain
* if it is null, a default domain is used.
* @param bcode
* the bytecode for the loaded class.
* @since 3.22
*/
public static Class toClass(String className,Class neighbor,ClassLoader loader,ProtectionDomain domain,byte[] bcode)
throws CannotCompileException{
try{
return privileged.defineClass(className, bcode, 0, bcode.length, neighbor, loader, domain);
}catch (RuntimeException e){
throw e;
}catch (CannotCompileException e){
throw e;
}catch (ClassFormatError e){
Throwable t = e.getCause();
throw new CannotCompileException(t == null ? e : t);
}catch (Exception e){
throw new CannotCompileException(e);
}
}
private DefineClassHelper(){
}
}
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