/*
* Copyright 2003-2009 the original author or authors.
*
* 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 org.codehaus.groovy.classgen.asm;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.objectweb.asm.MethodVisitor;
import static org.objectweb.asm.Opcodes.*;
public class MopWriter {
private static class MopKey {
int hash = 0;
String name;
Parameter[] params;
MopKey(String name, Parameter[] params) {
this.name = name;
this.params = params;
hash = name.hashCode() << 2 + params.length;
}
public int hashCode() {
return hash;
}
public boolean equals(Object obj) {
MopKey other = (MopKey) obj;
return other.name.equals(name) && equalParameterTypes(other.params,params);
}
}
private WriterController controller;
public MopWriter(WriterController wc) {
controller = wc;
}
public void createMopMethods() {
ClassNode classNode = controller.getClassNode();
if (classNode.declaresInterface(ClassHelper.GENERATED_CLOSURE_Type)) {
return;
}
visitMopMethodList(classNode.getMethods(), true);
visitMopMethodList(classNode.getSuperClass().getAllDeclaredMethods(), false);
}
/**
* filters a list of method for MOP methods. For all methods that are no
* MOP methods a MOP method is created if the method is not public and the
* call would be a call on "this" (isThis == true). If the call is not on
* "this", then the call is a call on "super" and all methods are used,
* unless they are already a MOP method
*
* @param methods unfiltered list of methods for MOP
* @param isThis if true, then we are creating a MOP method on "this", "super" else
* @see #generateMopCalls(LinkedList, boolean)
*/
private void visitMopMethodList(List methods, boolean isThis) {
HashMap<MopKey, MethodNode> mops = new HashMap<MopKey, MethodNode>();
LinkedList<MethodNode> mopCalls = new LinkedList<MethodNode>();
for (Object method : methods) {
MethodNode mn = (MethodNode) method;
if ((mn.getModifiers() & ACC_ABSTRACT) != 0) continue;
if (mn.isStatic()) continue;
// no this$ methods for protected/public isThis=true
// super$ method for protected/public isThis=false
// --> results in XOR
if (isThis ^ (mn.getModifiers() & (ACC_PUBLIC | ACC_PROTECTED)) == 0) continue;
String methodName = mn.getName();
if (isMopMethod(methodName)) {
mops.put(new MopKey(methodName, mn.getParameters()), mn);
continue;
}
if (methodName.startsWith("<")) continue;
String name = getMopMethodName(mn, isThis);
MopKey key = new MopKey(name, mn.getParameters());
if (mops.containsKey(key)) continue;
mops.put(key, mn);
mopCalls.add(mn);
}
generateMopCalls(mopCalls, isThis);
mopCalls.clear();
mops.clear();
}
/**
* creates a MOP method name from a method
*
* @param method the method to be called by the mop method
* @param useThis if true, then it is a call on "this", "super" else
* @return the mop method name
*/
public static String getMopMethodName(MethodNode method, boolean useThis) {
ClassNode declaringNode = method.getDeclaringClass();
int distance = 0;
for (; declaringNode != null; declaringNode = declaringNode.getSuperClass()) {
distance++;
}
return (useThis ? "this" : "super") + "$" + distance + "$" + method.getName();
}
/**
* method to determine if a method is a MOP method. This is done by the
* method name. If the name starts with "this$" or "super$" but does not
* contain "$dist$", then it is an MOP method
*
* @param methodName name of the method to test
* @return true if the method is a MOP method
*/
public static boolean isMopMethod(String methodName) {
return (methodName.startsWith("this$") ||
methodName.startsWith("super$")) && !methodName.contains("$dist$");
}
/**
* generates a Meta Object Protocol method, that is used to call a non public
* method, or to make a call to super.
*
* @param mopCalls list of methods a mop call method should be generated for
* @param useThis true if "this" should be used for the naming
*/
private void generateMopCalls(LinkedList<MethodNode> mopCalls, boolean useThis) {
for (MethodNode method : mopCalls) {
String name = getMopMethodName(method, useThis);
Parameter[] parameters = method.getParameters();
String methodDescriptor = BytecodeHelper.getMethodDescriptor(method.getReturnType(), method.getParameters());
MethodVisitor mv = controller.getClassVisitor().visitMethod(ACC_PUBLIC | ACC_SYNTHETIC, name, methodDescriptor, null, null);
controller.setMethodVisitor(mv);
mv.visitVarInsn(ALOAD, 0);
int newRegister = 1;
OperandStack operandStack = controller.getOperandStack();
for (Parameter parameter : parameters) {
ClassNode type = parameter.getType();
operandStack.load(parameter.getType(), newRegister);
// increment to next register, double/long are using two places
newRegister++;
if (type == ClassHelper.double_TYPE || type == ClassHelper.long_TYPE) newRegister++;
}
operandStack.remove(parameters.length);
mv.visitMethodInsn(INVOKESPECIAL, BytecodeHelper.getClassInternalName(method.getDeclaringClass()), method.getName(), methodDescriptor);
BytecodeHelper.doReturn(mv, method.getReturnType());
mv.visitMaxs(0, 0);
mv.visitEnd();
controller.getClassNode().addMethod(name, ACC_PUBLIC | ACC_SYNTHETIC, method.getReturnType(), parameters, null, null);
}
}
private static boolean equalParameterTypes(Parameter[] p1, Parameter[] p2) {
if (p1.length!=p2.length) return false;
for (int i=0; i<p1.length; i++) {
if (!p1[i].getType().equals(p2[i].getType())) return false;
}
return true;
}
}