private static CtMethod delegator0(CtMethod delegate, CtClass declaring)
throws CannotCompileException, NotFoundException {
MethodInfo deleInfo = delegate.getMethodInfo2();
String methodName = deleInfo.getName();
String desc = deleInfo.getDescriptor();
ConstPool cp = declaring.getClassFile2().getConstPool();
MethodInfo minfo = new MethodInfo(cp, methodName, desc);
minfo.setAccessFlags(deleInfo.getAccessFlags());
ExceptionsAttribute eattr = deleInfo.getExceptionsAttribute();
if (eattr != null) minfo.setExceptionsAttribute((ExceptionsAttribute) eattr.copy(cp, null));
Bytecode code = new Bytecode(cp, 0, 0);
boolean isStatic = Modifier.isStatic(delegate.getModifiers());
CtClass deleClass = delegate.getDeclaringClass();
CtClass[] params = delegate.getParameterTypes();
int s;
if (isStatic) {
s = code.addLoadParameters(params, 0);
code.addInvokestatic(deleClass, methodName, desc);
} else {
code.addLoad(0, deleClass);
s = code.addLoadParameters(params, 1);
code.addInvokespecial(deleClass, methodName, desc);
}
code.addReturn(delegate.getReturnType());
code.setMaxLocals(++s);
code.setMaxStack(s < 2 ? 2 : s); // for a 2-word return value
minfo.setCodeAttribute(code.toCodeAttribute());
return new CtMethod(minfo, declaring);
}
/**
* add a bogus constructor call to a bytecode sequence so a constructor can pass bytecode
* validation
*
* @param bytecode
*/
public static boolean addBogusConstructorCall(ClassFile file, Bytecode code) {
MethodInfo constructorToCall = null;
for (Object meth : file.getMethods()) {
MethodInfo m = (MethodInfo) meth;
if (m.getName().equals("<init>")) {
constructorToCall = m;
break;
}
}
if (constructorToCall == null) {
return false;
}
// push this onto the stack
code.add(Bytecode.ALOAD_0);
String[] params =
DescriptorUtils.descriptorStringToParameterArray(constructorToCall.getDescriptor());
for (String p : params) {
// int char short boolean byte
if (p.equals("I") || p.equals("C") || p.equals("S") || p.equals("Z") || p.equals("B")) {
// push integer 0
code.add(Opcode.ICONST_0);
}
// long
else if (p.equals("J")) {
code.add(Opcode.LCONST_0);
}
// double
else if (p.equals("D")) {
code.add(Opcode.DCONST_0);
}
// float
else if (p.equals("F")) {
code.add(Opcode.FCONST_0);
}
// arrays and reference types
else {
code.add(Opcode.ACONST_NULL);
}
}
// all our args should be pushed onto the stack, call the constructor
code.addInvokespecial(file.getName(), "<init>", constructorToCall.getDescriptor());
code.add(Opcode.RETURN);
return true;
}
/**
* When creates the delegate initializer code when the delegate is injected into a method.
*
* <p>super initializer method is called first, and then _initMH is called
*
* @param file
* @param intializerMethodInfo
* @param delegateParameterPosition
* @return
*/
private Bytecode createDelegateInitializerCode(
ClassFile file, MethodInformation intializerMethodInfo, int delegateParameterPosition) {
Bytecode b = new Bytecode(file.getConstPool());
// we need to push all the pareters on the stack to call the corresponding
// superclass arguments
b.addAload(0); // load this
int localVariables = 1;
int actualDelegateParamterPosition = 0;
for (int i = 0; i < intializerMethodInfo.getMethod().getParameterTypes().length; ++i) {
if (i == delegateParameterPosition) {
// figure out the actual position of the delegate in the local
// variables
actualDelegateParamterPosition = localVariables;
}
Class<?> type = intializerMethodInfo.getMethod().getParameterTypes()[i];
BytecodeUtils.addLoadInstruction(
b, DescriptorUtils.classToStringRepresentation(type), localVariables);
if (type == long.class || type == double.class) {
localVariables = localVariables + 2;
} else {
localVariables++;
}
}
b.addInvokespecial(
file.getSuperclass(), intializerMethodInfo.getName(), intializerMethodInfo.getDescriptor());
// if this method returns a value it is now sitting on top of the stack
// we will leave it there are return it later
// now we need to call _initMH
b.addAload(0); // load this
b.addAload(actualDelegateParamterPosition); // load the delegate
b.addInvokevirtual(file.getName(), "_initMH", "(Ljava/lang/Object;)V");
// return the object from the top of the stack that we got from calling
// the superclass method earlier
BytecodeUtils.addReturnInstruction(b, intializerMethodInfo.getReturnType());
b.setMaxLocals(localVariables);
return b;
}
/** Add a method to a class that simply delegates to the parent implementation of the method */
public static void addDelegatingMethod(ClassFile file, MethodData mData)
throws BadBytecode, DuplicateMemberException {
MethodInfo m =
new MethodInfo(file.getConstPool(), mData.getMethodName(), mData.getDescriptor());
m.setAccessFlags(mData.getAccessFlags());
Bytecode code = new Bytecode(file.getConstPool());
String[] params = DescriptorUtils.descriptorStringToParameterArray(mData.getDescriptor());
code.add(Opcode.ALOAD_0); // push this
int count = 1; // zero is the this pointer
int maxLocals = 1;
for (String p : params) {
// int char short boolean byte
if (p.equals("I") || p.equals("C") || p.equals("S") || p.equals("Z") || p.equals("B")) {
// push integer 0
code.addIload(count);
maxLocals++;
}
// long
else if (p.equals("J")) {
code.addLload(count);
maxLocals += 2;
count++;
}
// double
else if (p.equals("D")) {
code.addDload(count);
maxLocals += 2;
count++;
}
// float
else if (p.equals("F")) {
code.addFload(count);
maxLocals++;
}
// arrays and reference types
else {
code.addAload(count);
maxLocals++;
}
count++;
}
code.addInvokespecial(file.getSuperclass(), mData.getMethodName(), mData.getDescriptor());
String p = DescriptorUtils.getReturnTypeInJvmFormat(mData.getDescriptor());
// int char short boolean byte
if (p.equals("I") || p.equals("C") || p.equals("S") || p.equals("Z") || p.equals("B")) {
code.add(Opcode.IRETURN);
}
// long
else if (p.equals("J")) {
code.add(Opcode.LRETURN);
}
// double
else if (p.equals("D")) {
code.add(Opcode.DRETURN);
}
// float
else if (p.equals("F")) {
code.add(Opcode.FRETURN);
}
// void
else if (p.equals("V")) {
code.add(Opcode.RETURN);
}
// arrays and reference types
else {
code.add(Opcode.ARETURN);
}
CodeAttribute ca = code.toCodeAttribute();
ca.computeMaxStack();
ca.setMaxLocals(maxLocals);
m.setCodeAttribute(ca);
file.addMethod(m);
}