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Groovy: A powerful multi-faceted language for the JVM
/*
* 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.codehaus.groovy.classgen.asm;
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.codehaus.groovy.ast.tools.ParameterUtils;
import org.objectweb.asm.MethodVisitor;
import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;
import static org.objectweb.asm.Opcodes.ACC_ABSTRACT;
import static org.objectweb.asm.Opcodes.ACC_BRIDGE;
import static org.objectweb.asm.Opcodes.ACC_PUBLIC;
import static org.objectweb.asm.Opcodes.ACC_SYNTHETIC;
import static org.objectweb.asm.Opcodes.ALOAD;
import static org.objectweb.asm.Opcodes.INVOKEINTERFACE;
import static org.objectweb.asm.Opcodes.INVOKESPECIAL;
public class MopWriter {
@FunctionalInterface
public interface Factory {
MopWriter create(WriterController controller);
}
public static final Factory FACTORY = MopWriter::new;
private static class MopKey {
final int hash;
final String name;
final 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) {
if (!(obj instanceof MopKey)) {
return false;
}
MopKey other = (MopKey) obj;
return other.name.equals(name) && ParameterUtils.parametersEqual(other.params, params);
}
}
//--------------------------------------------------------------------------
private final WriterController controller;
public MopWriter(WriterController controller) {
this.controller = Objects.requireNonNull(controller);
}
public void createMopMethods() {
ClassNode classNode = controller.getClassNode();
if (ClassHelper.isGeneratedFunction(classNode)) {
return;
}
Set currentClassSignatures = classNode.getMethods().stream()
.map(mn -> new MopKey(mn.getName(), mn.getParameters())).collect(Collectors.toSet());
visitMopMethodList(classNode.getMethods(), true, Collections.emptySet(), Collections.emptyList());
visitMopMethodList(classNode.getSuperClass().getAllDeclaredMethods(), false, currentClassSignatures, controller.getSuperMethodNames());
}
/**
* 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, Set useOnlyIfDeclaredHereToo, List orNameMentionedHere) {
Map mops = new HashMap<>();
LinkedList mopCalls = new LinkedList<>();
for (MethodNode mn : methods) {
// mop methods are helper for this and super calls and do direct calls
// to the target methods. Such a method cannot be abstract or a bridge
if ((mn.getModifiers() & (ACC_ABSTRACT | ACC_BRIDGE)) != 0) continue;
if (mn.isStatic()) continue;
// no this$ methods for non-private isThis=true
// super$ method for non-private isThis=false
// --> results in XOR
boolean isPrivate = Modifier.isPrivate(mn.getModifiers());
if (isThis ^ isPrivate) continue;
String methodName = mn.getName();
if (isMopMethod(methodName)) {
mops.put(new MopKey(methodName, mn.getParameters()), mn);
continue;
}
if (methodName.startsWith("<")) continue;
if (!useOnlyIfDeclaredHereToo.contains(new MopKey(methodName, mn.getParameters())) &&
!orNameMentionedHere.contains(methodName)) {
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 += 1;
}
return (useThis ? "this" : "super") + "$" + distance + "$" + method.getName();
}
/**
* Determines 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
*/
protected void generateMopCalls(LinkedList 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);
newRegister += 1; // increment to next register; double/long are using two places
if (type == ClassHelper.double_TYPE || type == ClassHelper.long_TYPE) newRegister += 1;
}
operandStack.remove(parameters.length);
ClassNode declaringClass = method.getDeclaringClass();
// JDK 8 support for default methods in interfaces
// TODO: this should probably be strengthened when we support the A.super.foo() syntax
int opcode = declaringClass.isInterface() ? INVOKEINTERFACE : INVOKESPECIAL;
mv.visitMethodInsn(opcode, BytecodeHelper.getClassInternalName(declaringClass), method.getName(), methodDescriptor, declaringClass.isInterface());
BytecodeHelper.doReturn(mv, method.getReturnType());
mv.visitMaxs(0, 0);
mv.visitEnd();
controller.getClassNode().addMethod(name, ACC_PUBLIC | ACC_SYNTHETIC, method.getReturnType(), parameters, null, null);
}
}
@Deprecated
public static boolean equalParameterTypes(Parameter[] p1, Parameter[] p2) {
return ParameterUtils.parametersEqual(p1, p2);
}
}